contrib/bind9/lib/dns/resolver.c

   1 /*
   2  * Copyright (C) 2004-2014  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id$ */
  19
  20 /*! \file */
  21
  22 #include <config.h>
  23
  24 #include <isc/log.h>
  25 #include <isc/platform.h>
  26 #include <isc/print.h>
  27 #include <isc/string.h>
  28 #include <isc/random.h>
  29 #include <isc/socket.h>
  30 #include <isc/stats.h>
  31 #include <isc/task.h>
  32 #include <isc/timer.h>
  33 #include <isc/util.h>
  34
  35 #include <dns/acl.h>
  36 #include <dns/adb.h>
  37 #include <dns/cache.h>
  38 #include <dns/db.h>
  39 #include <dns/dispatch.h>
  40 #include <dns/ds.h>
  41 #include <dns/events.h>
  42 #include <dns/forward.h>
  43 #include <dns/keytable.h>
  44 #include <dns/log.h>
  45 #include <dns/message.h>
  46 #include <dns/ncache.h>
  47 #include <dns/nsec.h>
  48 #include <dns/nsec3.h>
  49 #include <dns/opcode.h>
  50 #include <dns/peer.h>
  51 #include <dns/rbt.h>
  52 #include <dns/rcode.h>
  53 #include <dns/rdata.h>
  54 #include <dns/rdataclass.h>
  55 #include <dns/rdatalist.h>
  56 #include <dns/rdataset.h>
  57 #include <dns/rdatastruct.h>
  58 #include <dns/rdatatype.h>
  59 #include <dns/resolver.h>
  60 #include <dns/result.h>
  61 #include <dns/rootns.h>
  62 #include <dns/stats.h>
  63 #include <dns/tsig.h>
  64 #include <dns/validator.h>
  65
  66 #define DNS_RESOLVER_TRACE
  67 #ifdef DNS_RESOLVER_TRACE
  68 #define RTRACE(m)       isc_log_write(dns_lctx, \
  69                                       DNS_LOGCATEGORY_RESOLVER, \
  70                                       DNS_LOGMODULE_RESOLVER, \
  71                                       ISC_LOG_DEBUG(3), \
  72                                       "res %p: %s", res, (m))
  73 #define RRTRACE(r, m)   isc_log_write(dns_lctx, \
  74                                       DNS_LOGCATEGORY_RESOLVER, \
  75                                       DNS_LOGMODULE_RESOLVER, \
  76                                       ISC_LOG_DEBUG(3), \
  77                                       "res %p: %s", (r), (m))
  78 #define FCTXTRACE(m)    isc_log_write(dns_lctx, \
  79                                       DNS_LOGCATEGORY_RESOLVER, \
  80                                       DNS_LOGMODULE_RESOLVER, \
  81                                       ISC_LOG_DEBUG(3), \
  82                                       "fctx %p(%s): %s", fctx, fctx->info, (m))
  83 #define FCTXTRACE2(m1, m2) \
  84                         isc_log_write(dns_lctx, \
  85                                       DNS_LOGCATEGORY_RESOLVER, \
  86                                       DNS_LOGMODULE_RESOLVER, \
  87                                       ISC_LOG_DEBUG(3), \
  88                                       "fctx %p(%s): %s %s", \
  89                                       fctx, fctx->info, (m1), (m2))
  90 #define FTRACE(m)       isc_log_write(dns_lctx, \
  91                                       DNS_LOGCATEGORY_RESOLVER, \
  92                                       DNS_LOGMODULE_RESOLVER, \
  93                                       ISC_LOG_DEBUG(3), \
  94                                       "fetch %p (fctx %p(%s)): %s", \
  95                                       fetch, fetch->private, \
  96                                       fetch->private->info, (m))
  97 #define QTRACE(m)       isc_log_write(dns_lctx, \
  98                                       DNS_LOGCATEGORY_RESOLVER, \
  99                                       DNS_LOGMODULE_RESOLVER, \
 100                                       ISC_LOG_DEBUG(3), \
 101                                       "resquery %p (fctx %p(%s)): %s", \
 102                                       query, query->fctx, \
 103                                       query->fctx->info, (m))
 104 #else
 105 #define RTRACE(m)
 106 #define RRTRACE(r, m)
 107 #define FCTXTRACE(m)
 108 #define FCTXTRACE2(m1, m2)
 109 #define FTRACE(m)
 110 #define QTRACE(m)
 111 #endif
 112
 113 #define US_PER_SEC 1000000U
 114 /*
 115  * The maximum time we will wait for a single query.
 116  */
 117 #define MAX_SINGLE_QUERY_TIMEOUT 9U
 118 #define MAX_SINGLE_QUERY_TIMEOUT_US (MAX_SINGLE_QUERY_TIMEOUT*US_PER_SEC)
 119
 120 /*
 121  * We need to allow a individual query time to complete / timeout.
 122  */
 123 #define MINIMUM_QUERY_TIMEOUT (MAX_SINGLE_QUERY_TIMEOUT + 1U)
 124
 125 /* The default time in seconds for the whole query to live. */
 126 #ifndef DEFAULT_QUERY_TIMEOUT
 127 #define DEFAULT_QUERY_TIMEOUT MINIMUM_QUERY_TIMEOUT
 128 #endif
 129
 130 #ifndef MAXIMUM_QUERY_TIMEOUT
 131 #define MAXIMUM_QUERY_TIMEOUT 30 /* The maximum time in seconds for the whole query to live. */
 132 #endif
 133
 134 /* The default maximum number of recursions to follow before giving up. */
 135 #ifndef DEFAULT_RECURSION_DEPTH
 136 #define DEFAULT_RECURSION_DEPTH 7
 137 #endif
 138
 139 /* The default maximum number of iterative queries to allow before giving up. */
 140 #ifndef DEFAULT_MAX_QUERIES
 141 #define DEFAULT_MAX_QUERIES 50
 142 #endif
 143
 144 /*%
 145  * Maximum EDNS0 input packet size.
 146  */
 147 #define RECV_BUFFER_SIZE                4096            /* XXXRTH  Constant. */
 148 #define EDNSOPTS                        2
 149
 150 /*%
 151  * This defines the maximum number of timeouts we will permit before we
 152  * disable EDNS0 on the query.
 153  */
 154 #define MAX_EDNS0_TIMEOUTS      3
 155
 156 typedef struct fetchctx fetchctx_t;
 157
 158 typedef struct query {
 159         /* Locked by task event serialization. */
 160         unsigned int                    magic;
 161         fetchctx_t *                    fctx;
 162         isc_mem_t *                     mctx;
 163         dns_dispatchmgr_t *             dispatchmgr;
 164         dns_dispatch_t *                dispatch;
 165         isc_boolean_t                   exclusivesocket;
 166         dns_adbaddrinfo_t *             addrinfo;
 167         isc_socket_t *                  tcpsocket;
 168         isc_time_t                      start;
 169         dns_messageid_t                 id;
 170         dns_dispentry_t *               dispentry;
 171         ISC_LINK(struct query)          link;
 172         isc_buffer_t                    buffer;
 173         isc_buffer_t                    *tsig;
 174         dns_tsigkey_t                   *tsigkey;
 175         isc_socketevent_t               sendevent;
 176         unsigned int                    options;
 177         unsigned int                    attributes;
 178         unsigned int                    sends;
 179         unsigned int                    connects;
 180         unsigned char                   data[512];
 181 } resquery_t;
 182
 183 #define QUERY_MAGIC                     ISC_MAGIC('Q', '!', '!', '!')
 184 #define VALID_QUERY(query)              ISC_MAGIC_VALID(query, QUERY_MAGIC)
 185
 186 #define RESQUERY_ATTR_CANCELED          0x02
 187
 188 #define RESQUERY_CONNECTING(q)          ((q)->connects > 0)
 189 #define RESQUERY_CANCELED(q)            (((q)->attributes & \
 190                                           RESQUERY_ATTR_CANCELED) != 0)
 191 #define RESQUERY_SENDING(q)             ((q)->sends > 0)
 192
 193 typedef enum {
 194         fetchstate_init = 0,            /*%< Start event has not run yet. */
 195         fetchstate_active,
 196         fetchstate_done                 /*%< FETCHDONE events posted. */
 197 } fetchstate;
 198
 199 typedef enum {
 200         badns_unreachable = 0,
 201         badns_response,
 202         badns_validation
 203 } badnstype_t;
 204
 205 struct fetchctx {
 206         /*% Not locked. */
 207         unsigned int                    magic;
 208         dns_resolver_t *                res;
 209         dns_name_t                      name;
 210         dns_rdatatype_t                 type;
 211         unsigned int                    options;
 212         unsigned int                    bucketnum;
 213         char *                          info;
 214         isc_mem_t *                     mctx;
 215
 216         /*% Locked by appropriate bucket lock. */
 217         fetchstate                      state;
 218         isc_boolean_t                   want_shutdown;
 219         isc_boolean_t                   cloned;
 220         isc_boolean_t                   spilled;
 221         unsigned int                    references;
 222         isc_event_t                     control_event;
 223         ISC_LINK(struct fetchctx)       link;
 224         ISC_LIST(dns_fetchevent_t)      events;
 225         /*% Locked by task event serialization. */
 226         dns_name_t                      domain;
 227         dns_rdataset_t                  nameservers;
 228         unsigned int                    attributes;
 229         isc_timer_t *                   timer;
 230         isc_time_t                      expires;
 231         isc_interval_t                  interval;
 232         dns_message_t *                 qmessage;
 233         dns_message_t *                 rmessage;
 234         ISC_LIST(resquery_t)            queries;
 235         dns_adbfindlist_t               finds;
 236         dns_adbfind_t *                 find;
 237         dns_adbfindlist_t               altfinds;
 238         dns_adbfind_t *                 altfind;
 239         dns_adbaddrinfolist_t           forwaddrs;
 240         dns_adbaddrinfolist_t           altaddrs;
 241         isc_sockaddrlist_t              forwarders;
 242         dns_fwdpolicy_t                 fwdpolicy;
 243         isc_sockaddrlist_t              bad;
 244         isc_sockaddrlist_t              edns;
 245         isc_sockaddrlist_t              edns512;
 246         isc_sockaddrlist_t              bad_edns;
 247         dns_validator_t                 *validator;
 248         ISC_LIST(dns_validator_t)       validators;
 249         dns_db_t *                      cache;
 250         dns_adb_t *                     adb;
 251         isc_boolean_t                   ns_ttl_ok;
 252         isc_uint32_t                    ns_ttl;
 253
 254         /*%
 255          * The number of events we're waiting for.
 256          */
 257         unsigned int                    pending;
 258
 259         /*%
 260          * The number of times we've "restarted" the current
 261          * nameserver set.  This acts as a failsafe to prevent
 262          * us from pounding constantly on a particular set of
 263          * servers that, for whatever reason, are not giving
 264          * us useful responses, but are responding in such a
 265          * way that they are not marked "bad".
 266          */
 267         unsigned int                    restarts;
 268
 269         /*%
 270          * The number of timeouts that have occurred since we
 271          * last successfully received a response packet.  This
 272          * is used for EDNS0 black hole detection.
 273          */
 274         unsigned int                    timeouts;
 275
 276         /*%
 277          * Look aside state for DS lookups.
 278          */
 279         dns_name_t                      nsname;
 280         dns_fetch_t *                   nsfetch;
 281         dns_rdataset_t                  nsrrset;
 282
 283         /*%
 284          * Number of queries that reference this context.
 285          */
 286         unsigned int                    nqueries;
 287
 288         /*%
 289          * The reason to print when logging a successful
 290          * response to a query.
 291          */
 292         const char *                    reason;
 293
 294         /*%
 295          * Random numbers to use for mixing up server addresses.
 296          */
 297         isc_uint32_t                    rand_buf;
 298         isc_uint32_t                    rand_bits;
 299
 300         /*%
 301          * Fetch-local statistics for detailed logging.
 302          */
 303         isc_result_t                    result; /*%< fetch result  */
 304         isc_result_t                    vresult; /*%< validation result  */
 305         int                             exitline;
 306         isc_time_t                      start;
 307         isc_uint64_t                    duration;
 308         isc_boolean_t                   logged;
 309         unsigned int                    querysent;
 310         unsigned int                    totalqueries;
 311         unsigned int                    referrals;
 312         unsigned int                    lamecount;
 313         unsigned int                    neterr;
 314         unsigned int                    badresp;
 315         unsigned int                    adberr;
 316         unsigned int                    findfail;
 317         unsigned int                    valfail;
 318         isc_boolean_t                   timeout;
 319         dns_adbaddrinfo_t               *addrinfo;
 320         isc_sockaddr_t                  *client;
 321         unsigned int                    depth;
 322 };
 323
 324 #define FCTX_MAGIC                      ISC_MAGIC('F', '!', '!', '!')
 325 #define VALID_FCTX(fctx)                ISC_MAGIC_VALID(fctx, FCTX_MAGIC)
 326
 327 #define FCTX_ATTR_HAVEANSWER            0x0001
 328 #define FCTX_ATTR_GLUING                0x0002
 329 #define FCTX_ATTR_ADDRWAIT              0x0004
 330 #define FCTX_ATTR_SHUTTINGDOWN          0x0008
 331 #define FCTX_ATTR_WANTCACHE             0x0010
 332 #define FCTX_ATTR_WANTNCACHE            0x0020
 333 #define FCTX_ATTR_NEEDEDNS0             0x0040
 334 #define FCTX_ATTR_TRIEDFIND             0x0080
 335 #define FCTX_ATTR_TRIEDALT              0x0100
 336
 337 #define HAVE_ANSWER(f)          (((f)->attributes & FCTX_ATTR_HAVEANSWER) != \
 338                                  0)
 339 #define GLUING(f)               (((f)->attributes & FCTX_ATTR_GLUING) != \
 340                                  0)
 341 #define ADDRWAIT(f)             (((f)->attributes & FCTX_ATTR_ADDRWAIT) != \
 342                                  0)
 343 #define SHUTTINGDOWN(f)         (((f)->attributes & FCTX_ATTR_SHUTTINGDOWN) \
 344                                  != 0)
 345 #define WANTCACHE(f)            (((f)->attributes & FCTX_ATTR_WANTCACHE) != 0)
 346 #define WANTNCACHE(f)           (((f)->attributes & FCTX_ATTR_WANTNCACHE) != 0)
 347 #define NEEDEDNS0(f)            (((f)->attributes & FCTX_ATTR_NEEDEDNS0) != 0)
 348 #define TRIEDFIND(f)            (((f)->attributes & FCTX_ATTR_TRIEDFIND) != 0)
 349 #define TRIEDALT(f)             (((f)->attributes & FCTX_ATTR_TRIEDALT) != 0)
 350
 351 typedef struct {
 352         dns_adbaddrinfo_t *             addrinfo;
 353         fetchctx_t *                    fctx;
 354 } dns_valarg_t;
 355
 356 struct dns_fetch {
 357         unsigned int                    magic;
 358         fetchctx_t *                    private;
 359 };
 360
 361 #define DNS_FETCH_MAGIC                 ISC_MAGIC('F', 't', 'c', 'h')
 362 #define DNS_FETCH_VALID(fetch)          ISC_MAGIC_VALID(fetch, DNS_FETCH_MAGIC)
 363
 364 typedef struct fctxbucket {
 365         isc_task_t *                    task;
 366         isc_mutex_t                     lock;
 367         ISC_LIST(fetchctx_t)            fctxs;
 368         isc_boolean_t                   exiting;
 369         isc_mem_t *                     mctx;
 370 } fctxbucket_t;
 371
 372 typedef struct alternate {
 373         isc_boolean_t                   isaddress;
 374         union   {
 375                 isc_sockaddr_t          addr;
 376                 struct {
 377                         dns_name_t      name;
 378                         in_port_t       port;
 379                 } _n;
 380         } _u;
 381         ISC_LINK(struct alternate)      link;
 382 } alternate_t;
 383
 384 typedef struct dns_badcache dns_badcache_t;
 385 struct dns_badcache {
 386         dns_badcache_t *        next;
 387         dns_rdatatype_t         type;
 388         isc_time_t              expire;
 389         unsigned int            hashval;
 390         dns_name_t              name;
 391 };
 392 #define DNS_BADCACHE_SIZE 1021
 393 #define DNS_BADCACHE_TTL(fctx) \
 394         (((fctx)->res->lame_ttl > 30 ) ? (fctx)->res->lame_ttl : 30)
 395
 396 struct dns_resolver {
 397         /* Unlocked. */
 398         unsigned int                    magic;
 399         isc_mem_t *                     mctx;
 400         isc_mutex_t                     lock;
 401         isc_mutex_t                     nlock;
 402         isc_mutex_t                     primelock;
 403         dns_rdataclass_t                rdclass;
 404         isc_socketmgr_t *               socketmgr;
 405         isc_timermgr_t *                timermgr;
 406         isc_taskmgr_t *                 taskmgr;
 407         dns_view_t *                    view;
 408         isc_boolean_t                   frozen;
 409         unsigned int                    options;
 410         dns_dispatchmgr_t *             dispatchmgr;
 411         dns_dispatchset_t *             dispatches4;
 412         isc_boolean_t                   exclusivev4;
 413         dns_dispatchset_t *             dispatches6;
 414         isc_boolean_t                   exclusivev6;
 415         unsigned int                    nbuckets;
 416         fctxbucket_t *                  buckets;
 417         isc_uint32_t                    lame_ttl;
 418         ISC_LIST(alternate_t)           alternates;
 419         isc_uint16_t                    udpsize;
 420 #if USE_ALGLOCK
 421         isc_rwlock_t                    alglock;
 422 #endif
 423         dns_rbt_t *                     algorithms;
 424 #if USE_MBSLOCK
 425         isc_rwlock_t                    mbslock;
 426 #endif
 427         dns_rbt_t *                     mustbesecure;
 428         unsigned int                    spillatmax;
 429         unsigned int                    spillatmin;
 430         isc_timer_t *                   spillattimer;
 431         isc_boolean_t                   zero_no_soa_ttl;
 432         unsigned int                    query_timeout;
 433         unsigned int                    maxdepth;
 434
 435         /* Locked by lock. */
 436         unsigned int                    references;
 437         isc_boolean_t                   exiting;
 438         isc_eventlist_t                 whenshutdown;
 439         unsigned int                    activebuckets;
 440         isc_boolean_t                   priming;
 441         unsigned int                    spillat;        /* clients-per-query */
 442
 443         /* Bad cache. */
 444         dns_badcache_t  **              badcache;
 445         unsigned int                    badcount;
 446         unsigned int                    badhash;
 447         unsigned int                    badsweep;
 448
 449         /* Locked by primelock. */
 450         dns_fetch_t *                   primefetch;
 451         /* Locked by nlock. */
 452         unsigned int                    nfctx;
 453 };
 454
 455 #define RES_MAGIC                       ISC_MAGIC('R', 'e', 's', '!')
 456 #define VALID_RESOLVER(res)             ISC_MAGIC_VALID(res, RES_MAGIC)
 457
 458 /*%
 459  * Private addrinfo flags.  These must not conflict with DNS_FETCHOPT_NOEDNS0,
 460  * which we also use as an addrinfo flag.
 461  */
 462 #define FCTX_ADDRINFO_MARK              0x0001
 463 #define FCTX_ADDRINFO_FORWARDER         0x1000
 464 #define FCTX_ADDRINFO_TRIED             0x2000
 465 #define UNMARKED(a)                     (((a)->flags & FCTX_ADDRINFO_MARK) \
 466                                          == 0)
 467 #define ISFORWARDER(a)                  (((a)->flags & \
 468                                          FCTX_ADDRINFO_FORWARDER) != 0)
 469 #define TRIED(a)                        (((a)->flags & \
 470                                          FCTX_ADDRINFO_TRIED) != 0)
 471
 472 #define NXDOMAIN(r) (((r)->attributes & DNS_RDATASETATTR_NXDOMAIN) != 0)
 473 #define NEGATIVE(r) (((r)->attributes & DNS_RDATASETATTR_NEGATIVE) != 0)
 474
 475 static void destroy(dns_resolver_t *res);
 476 static void empty_bucket(dns_resolver_t *res);
 477 static isc_result_t resquery_send(resquery_t *query);
 478 static void resquery_response(isc_task_t *task, isc_event_t *event);
 479 static void resquery_connected(isc_task_t *task, isc_event_t *event);
 480 static void fctx_try(fetchctx_t *fctx, isc_boolean_t retrying,
 481                      isc_boolean_t badcache);
 482 static void fctx_destroy(fetchctx_t *fctx);
 483 static isc_boolean_t fctx_unlink(fetchctx_t *fctx);
 484 static isc_result_t ncache_adderesult(dns_message_t *message,
 485                                       dns_db_t *cache, dns_dbnode_t *node,
 486                                       dns_rdatatype_t covers,
 487                                       isc_stdtime_t now, dns_ttl_t maxttl,
 488                                       isc_boolean_t optout,
 489                                       isc_boolean_t secure,
 490                                       dns_rdataset_t *ardataset,
 491                                       isc_result_t *eresultp);
 492 static void validated(isc_task_t *task, isc_event_t *event);
 493 static isc_boolean_t maybe_destroy(fetchctx_t *fctx, isc_boolean_t locked);
 494 static void add_bad(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
 495                     isc_result_t reason, badnstype_t badtype);
 496 static inline isc_result_t findnoqname(fetchctx_t *fctx, dns_name_t *name,
 497                                        dns_rdatatype_t type,
 498                                        dns_name_t **noqname);
 499
 500 /*%
 501  * Increment resolver-related statistics counters.
 502  */
 503 static inline void
 504 inc_stats(dns_resolver_t *res, isc_statscounter_t counter) {
 505         if (res->view->resstats != NULL)
 506                 isc_stats_increment(res->view->resstats, counter);
 507 }
 508
 509 static isc_result_t
 510 valcreate(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo, dns_name_t *name,
 511           dns_rdatatype_t type, dns_rdataset_t *rdataset,
 512           dns_rdataset_t *sigrdataset, unsigned int valoptions,
 513           isc_task_t *task)
 514 {
 515         dns_validator_t *validator = NULL;
 516         dns_valarg_t *valarg;
 517         isc_result_t result;
 518
 519         valarg = isc_mem_get(fctx->mctx, sizeof(*valarg));
 520         if (valarg == NULL)
 521                 return (ISC_R_NOMEMORY);
 522
 523         valarg->fctx = fctx;
 524         valarg->addrinfo = addrinfo;
 525
 526         if (!ISC_LIST_EMPTY(fctx->validators))
 527                 INSIST((valoptions & DNS_VALIDATOR_DEFER) != 0);
 528
 529         result = dns_validator_create(fctx->res->view, name, type, rdataset,
 530                                       sigrdataset, fctx->rmessage,
 531                                       valoptions, task, validated, valarg,
 532                                       &validator);
 533         if (result == ISC_R_SUCCESS) {
 534                 inc_stats(fctx->res, dns_resstatscounter_val);
 535                 if ((valoptions & DNS_VALIDATOR_DEFER) == 0) {
 536                         INSIST(fctx->validator == NULL);
 537                         fctx->validator = validator;
 538                 }
 539                 ISC_LIST_APPEND(fctx->validators, validator, link);
 540         } else
 541                 isc_mem_put(fctx->mctx, valarg, sizeof(*valarg));
 542         return (result);
 543 }
 544
 545 static isc_boolean_t
 546 rrsig_fromchildzone(fetchctx_t *fctx, dns_rdataset_t *rdataset) {
 547         dns_namereln_t namereln;
 548         dns_rdata_rrsig_t rrsig;
 549         dns_rdata_t rdata = DNS_RDATA_INIT;
 550         int order;
 551         isc_result_t result;
 552         unsigned int labels;
 553
 554         for (result = dns_rdataset_first(rdataset);
 555              result == ISC_R_SUCCESS;
 556              result = dns_rdataset_next(rdataset)) {
 557                 dns_rdataset_current(rdataset, &rdata);
 558                 result = dns_rdata_tostruct(&rdata, &rrsig, NULL);
 559                 RUNTIME_CHECK(result == ISC_R_SUCCESS);
 560                 namereln = dns_name_fullcompare(&rrsig.signer, &fctx->domain,
 561                                                 &order, &labels);
 562                 if (namereln == dns_namereln_subdomain)
 563                         return (ISC_TRUE);
 564                 dns_rdata_reset(&rdata);
 565         }
 566         return (ISC_FALSE);
 567 }
 568
 569 static isc_boolean_t
 570 fix_mustbedelegationornxdomain(dns_message_t *message, fetchctx_t *fctx) {
 571         dns_name_t *name;
 572         dns_name_t *domain = &fctx->domain;
 573         dns_rdataset_t *rdataset;
 574         dns_rdatatype_t type;
 575         isc_result_t result;
 576         isc_boolean_t keep_auth = ISC_FALSE;
 577
 578         if (message->rcode == dns_rcode_nxdomain)
 579                 return (ISC_FALSE);
 580
 581         /*
 582          * A DS RRset can appear anywhere in a zone, even for a delegation-only
 583          * zone.  So a response to an explicit query for this type should be
 584          * excluded from delegation-only fixup.
 585          *
 586          * SOA, NS, and DNSKEY can only exist at a zone apex, so a postive
 587          * response to a query for these types can never violate the
 588          * delegation-only assumption: if the query name is below a
 589          * zone cut, the response should normally be a referral, which should
 590          * be accepted; if the query name is below a zone cut but the server
 591          * happens to have authority for the zone of the query name, the
 592          * response is a (non-referral) answer.  But this does not violate
 593          * delegation-only because the query name must be in a different zone
 594          * due to the "apex-only" nature of these types.  Note that if the
 595          * remote server happens to have authority for a child zone of a
 596          * delegation-only zone, we may still incorrectly "fix" the response
 597          * with NXDOMAIN for queries for other types.  Unfortunately it's
 598          * generally impossible to differentiate this case from violation of
 599          * the delegation-only assumption.  Once the resolver learns the
 600          * correct zone cut, possibly via a separate query for an "apex-only"
 601          * type, queries for other types will be resolved correctly.
 602          *
 603          * A query for type ANY will be accepted if it hits an exceptional
 604          * type above in the answer section as it should be from a child
 605          * zone.
 606          *
 607          * Also accept answers with RRSIG records from the child zone.
 608          * Direct queries for RRSIG records should not be answered from
 609          * the parent zone.
 610          */
 611
 612         if (message->counts[DNS_SECTION_ANSWER] != 0 &&
 613             (fctx->type == dns_rdatatype_ns ||
 614              fctx->type == dns_rdatatype_ds ||
 615              fctx->type == dns_rdatatype_soa ||
 616              fctx->type == dns_rdatatype_any ||
 617              fctx->type == dns_rdatatype_rrsig ||
 618              fctx->type == dns_rdatatype_dnskey)) {
 619                 result = dns_message_firstname(message, DNS_SECTION_ANSWER);
 620                 while (result == ISC_R_SUCCESS) {
 621                         name = NULL;
 622                         dns_message_currentname(message, DNS_SECTION_ANSWER,
 623                                                 &name);
 624                         for (rdataset = ISC_LIST_HEAD(name->list);
 625                              rdataset != NULL;
 626                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
 627                                 if (!dns_name_equal(name, &fctx->name))
 628                                         continue;
 629                                 type = rdataset->type;
 630                                 /*
 631                                  * RRsig from child?
 632                                  */
 633                                 if (type == dns_rdatatype_rrsig &&
 634                                     rrsig_fromchildzone(fctx, rdataset))
 635                                         return (ISC_FALSE);
 636                                 /*
 637                                  * Direct query for apex records or DS.
 638                                  */
 639                                 if (fctx->type == type &&
 640                                     (type == dns_rdatatype_ds ||
 641                                      type == dns_rdatatype_ns ||
 642                                      type == dns_rdatatype_soa ||
 643                                      type == dns_rdatatype_dnskey))
 644                                         return (ISC_FALSE);
 645                                 /*
 646                                  * Indirect query for apex records or DS.
 647                                  */
 648                                 if (fctx->type == dns_rdatatype_any &&
 649                                     (type == dns_rdatatype_ns ||
 650                                      type == dns_rdatatype_ds ||
 651                                      type == dns_rdatatype_soa ||
 652                                      type == dns_rdatatype_dnskey))
 653                                         return (ISC_FALSE);
 654                         }
 655                         result = dns_message_nextname(message,
 656                                                       DNS_SECTION_ANSWER);
 657                 }
 658         }
 659
 660         /*
 661          * A NODATA response to a DS query?
 662          */
 663         if (fctx->type == dns_rdatatype_ds &&
 664             message->counts[DNS_SECTION_ANSWER] == 0)
 665                 return (ISC_FALSE);
 666
 667         /* Look for referral or indication of answer from child zone? */
 668         if (message->counts[DNS_SECTION_AUTHORITY] == 0)
 669                 goto munge;
 670
 671         result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
 672         while (result == ISC_R_SUCCESS) {
 673                 name = NULL;
 674                 dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
 675                 for (rdataset = ISC_LIST_HEAD(name->list);
 676                      rdataset != NULL;
 677                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
 678                         type = rdataset->type;
 679                         if (type == dns_rdatatype_soa &&
 680                             dns_name_equal(name, domain))
 681                                 keep_auth = ISC_TRUE;
 682
 683                         if (type != dns_rdatatype_ns &&
 684                             type != dns_rdatatype_soa &&
 685                             type != dns_rdatatype_rrsig)
 686                                 continue;
 687
 688                         if (type == dns_rdatatype_rrsig) {
 689                                 if (rrsig_fromchildzone(fctx, rdataset))
 690                                         return (ISC_FALSE);
 691                                 else
 692                                         continue;
 693                         }
 694
 695                         /* NS or SOA records. */
 696                         if (dns_name_equal(name, domain)) {
 697                                 /*
 698                                  * If a query for ANY causes a negative
 699                                  * response, we can be sure that this is
 700                                  * an empty node.  For other type of queries
 701                                  * we cannot differentiate an empty node
 702                                  * from a node that just doesn't have that
 703                                  * type of record.  We only accept the former
 704                                  * case.
 705                                  */
 706                                 if (message->counts[DNS_SECTION_ANSWER] == 0 &&
 707                                     fctx->type == dns_rdatatype_any)
 708                                         return (ISC_FALSE);
 709                         } else if (dns_name_issubdomain(name, domain)) {
 710                                 /* Referral or answer from child zone. */
 711                                 return (ISC_FALSE);
 712                         }
 713                 }
 714                 result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
 715         }
 716
 717  munge:
 718         message->rcode = dns_rcode_nxdomain;
 719         message->counts[DNS_SECTION_ANSWER] = 0;
 720         if (!keep_auth)
 721                 message->counts[DNS_SECTION_AUTHORITY] = 0;
 722         message->counts[DNS_SECTION_ADDITIONAL] = 0;
 723         return (ISC_TRUE);
 724 }
 725
 726 static inline isc_result_t
 727 fctx_starttimer(fetchctx_t *fctx) {
 728         /*
 729          * Start the lifetime timer for fctx.
 730          *
 731          * This is also used for stopping the idle timer; in that
 732          * case we must purge events already posted to ensure that
 733          * no further idle events are delivered.
 734          */
 735         return (isc_timer_reset(fctx->timer, isc_timertype_once,
 736                                 &fctx->expires, NULL, ISC_TRUE));
 737 }
 738
 739 static inline void
 740 fctx_stoptimer(fetchctx_t *fctx) {
 741         isc_result_t result;
 742
 743         /*
 744          * We don't return a result if resetting the timer to inactive fails
 745          * since there's nothing to be done about it.  Resetting to inactive
 746          * should never fail anyway, since the code as currently written
 747          * cannot fail in that case.
 748          */
 749         result = isc_timer_reset(fctx->timer, isc_timertype_inactive,
 750                                   NULL, NULL, ISC_TRUE);
 751         if (result != ISC_R_SUCCESS) {
 752                 UNEXPECTED_ERROR(__FILE__, __LINE__,
 753                                  "isc_timer_reset(): %s",
 754                                  isc_result_totext(result));
 755         }
 756 }
 757
 758
 759 static inline isc_result_t
 760 fctx_startidletimer(fetchctx_t *fctx, isc_interval_t *interval) {
 761         /*
 762          * Start the idle timer for fctx.  The lifetime timer continues
 763          * to be in effect.
 764          */
 765         return (isc_timer_reset(fctx->timer, isc_timertype_once,
 766                                 &fctx->expires, interval, ISC_FALSE));
 767 }
 768
 769 /*
 770  * Stopping the idle timer is equivalent to calling fctx_starttimer(), but
 771  * we use fctx_stopidletimer for readability in the code below.
 772  */
 773 #define fctx_stopidletimer      fctx_starttimer
 774
 775
 776 static inline void
 777 resquery_destroy(resquery_t **queryp) {
 778         resquery_t *query;
 779
 780         REQUIRE(queryp != NULL);
 781         query = *queryp;
 782         REQUIRE(!ISC_LINK_LINKED(query, link));
 783
 784         INSIST(query->tcpsocket == NULL);
 785
 786         query->fctx->nqueries--;
 787         if (SHUTTINGDOWN(query->fctx)) {
 788                 dns_resolver_t *res = query->fctx->res;
 789                 if (maybe_destroy(query->fctx, ISC_FALSE))
 790                         empty_bucket(res);
 791         }
 792         query->magic = 0;
 793         isc_mem_put(query->mctx, query, sizeof(*query));
 794         *queryp = NULL;
 795 }
 796
 797 static void
 798 fctx_cancelquery(resquery_t **queryp, dns_dispatchevent_t **deventp,
 799                  isc_time_t *finish, isc_boolean_t no_response)
 800 {
 801         fetchctx_t *fctx;
 802         resquery_t *query;
 803         unsigned int rtt, rttms;
 804         unsigned int factor;
 805         dns_adbfind_t *find;
 806         dns_adbaddrinfo_t *addrinfo;
 807         isc_socket_t *socket;
 808
 809         query = *queryp;
 810         fctx = query->fctx;
 811
 812         FCTXTRACE("cancelquery");
 813
 814         REQUIRE(!RESQUERY_CANCELED(query));
 815
 816         query->attributes |= RESQUERY_ATTR_CANCELED;
 817
 818         /*
 819          * Should we update the RTT?
 820          */
 821         if (finish != NULL || no_response) {
 822                 if (finish != NULL) {
 823                         /*
 824                          * We have both the start and finish times for this
 825                          * packet, so we can compute a real RTT.
 826                          */
 827                         rtt = (unsigned int)isc_time_microdiff(finish,
 828                                                                &query->start);
 829                         factor = DNS_ADB_RTTADJDEFAULT;
 830
 831                         rttms = rtt / 1000;
 832                         if (rttms < DNS_RESOLVER_QRYRTTCLASS0) {
 833                                 inc_stats(fctx->res,
 834                                           dns_resstatscounter_queryrtt0);
 835                         } else if (rttms < DNS_RESOLVER_QRYRTTCLASS1) {
 836                                 inc_stats(fctx->res,
 837                                           dns_resstatscounter_queryrtt1);
 838                         } else if (rttms < DNS_RESOLVER_QRYRTTCLASS2) {
 839                                 inc_stats(fctx->res,
 840                                           dns_resstatscounter_queryrtt2);
 841                         } else if (rttms < DNS_RESOLVER_QRYRTTCLASS3) {
 842                                 inc_stats(fctx->res,
 843                                           dns_resstatscounter_queryrtt3);
 844                         } else if (rttms < DNS_RESOLVER_QRYRTTCLASS4) {
 845                                 inc_stats(fctx->res,
 846                                           dns_resstatscounter_queryrtt4);
 847                         } else {
 848                                 inc_stats(fctx->res,
 849                                           dns_resstatscounter_queryrtt5);
 850                         }
 851                 } else {
 852                         /*
 853                          * We don't have an RTT for this query.  Maybe the
 854                          * packet was lost, or maybe this server is very
 855                          * slow.  We don't know.  Increase the RTT.
 856                          */
 857                         INSIST(no_response);
 858                         rtt = query->addrinfo->srtt + 200000;
 859                         if (rtt > MAX_SINGLE_QUERY_TIMEOUT_US)
 860                                 rtt = MAX_SINGLE_QUERY_TIMEOUT_US;
 861                         /*
 862                          * Replace the current RTT with our value.
 863                          */
 864                         factor = DNS_ADB_RTTADJREPLACE;
 865                 }
 866                 dns_adb_adjustsrtt(fctx->adb, query->addrinfo, rtt, factor);
 867         }
 868
 869         /* Remember that the server has been tried. */
 870         if (!TRIED(query->addrinfo)) {
 871                 dns_adb_changeflags(fctx->adb, query->addrinfo,
 872                                     FCTX_ADDRINFO_TRIED, FCTX_ADDRINFO_TRIED);
 873         }
 874
 875         /*
 876          * Age RTTs of servers not tried.
 877          */
 878         factor = DNS_ADB_RTTADJAGE;
 879         if (finish != NULL)
 880                 for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
 881                      addrinfo != NULL;
 882                      addrinfo = ISC_LIST_NEXT(addrinfo, publink))
 883                         if (UNMARKED(addrinfo))
 884                                 dns_adb_adjustsrtt(fctx->adb, addrinfo,
 885                                                    0, factor);
 886
 887         if (finish != NULL && TRIEDFIND(fctx))
 888                 for (find = ISC_LIST_HEAD(fctx->finds);
 889                      find != NULL;
 890                      find = ISC_LIST_NEXT(find, publink))
 891                         for (addrinfo = ISC_LIST_HEAD(find->list);
 892                              addrinfo != NULL;
 893                              addrinfo = ISC_LIST_NEXT(addrinfo, publink))
 894                                 if (UNMARKED(addrinfo))
 895                                         dns_adb_adjustsrtt(fctx->adb, addrinfo,
 896                                                            0, factor);
 897
 898         if (finish != NULL && TRIEDALT(fctx)) {
 899                 for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs);
 900                      addrinfo != NULL;
 901                      addrinfo = ISC_LIST_NEXT(addrinfo, publink))
 902                         if (UNMARKED(addrinfo))
 903                                 dns_adb_adjustsrtt(fctx->adb, addrinfo,
 904                                                    0, factor);
 905                 for (find = ISC_LIST_HEAD(fctx->altfinds);
 906                      find != NULL;
 907                      find = ISC_LIST_NEXT(find, publink))
 908                         for (addrinfo = ISC_LIST_HEAD(find->list);
 909                              addrinfo != NULL;
 910                              addrinfo = ISC_LIST_NEXT(addrinfo, publink))
 911                                 if (UNMARKED(addrinfo))
 912                                         dns_adb_adjustsrtt(fctx->adb, addrinfo,
 913                                                            0, factor);
 914         }
 915
 916         /*
 917          * Check for any outstanding socket events.  If they exist, cancel
 918          * them and let the event handlers finish the cleanup.  The resolver
 919          * only needs to worry about managing the connect and send events;
 920          * the dispatcher manages the recv events.
 921          */
 922         if (RESQUERY_CONNECTING(query)) {
 923                 /*
 924                  * Cancel the connect.
 925                  */
 926                 if (query->tcpsocket != NULL) {
 927                         isc_socket_cancel(query->tcpsocket, NULL,
 928                                           ISC_SOCKCANCEL_CONNECT);
 929                 } else if (query->dispentry != NULL) {
 930                         INSIST(query->exclusivesocket);
 931                         socket = dns_dispatch_getentrysocket(query->dispentry);
 932                         if (socket != NULL)
 933                                 isc_socket_cancel(socket, NULL,
 934                                                   ISC_SOCKCANCEL_CONNECT);
 935                 }
 936         } else if (RESQUERY_SENDING(query)) {
 937                 /*
 938                  * Cancel the pending send.
 939                  */
 940                 if (query->exclusivesocket && query->dispentry != NULL)
 941                         socket = dns_dispatch_getentrysocket(query->dispentry);
 942                 else
 943                         socket = dns_dispatch_getsocket(query->dispatch);
 944                 if (socket != NULL)
 945                         isc_socket_cancel(socket, NULL, ISC_SOCKCANCEL_SEND);
 946         }
 947
 948         if (query->dispentry != NULL)
 949                 dns_dispatch_removeresponse(&query->dispentry, deventp);
 950
 951         ISC_LIST_UNLINK(fctx->queries, query, link);
 952
 953         if (query->tsig != NULL)
 954                 isc_buffer_free(&query->tsig);
 955
 956         if (query->tsigkey != NULL)
 957                 dns_tsigkey_detach(&query->tsigkey);
 958
 959         if (query->dispatch != NULL)
 960                 dns_dispatch_detach(&query->dispatch);
 961
 962         if (! (RESQUERY_CONNECTING(query) || RESQUERY_SENDING(query)))
 963                 /*
 964                  * It's safe to destroy the query now.
 965                  */
 966                 resquery_destroy(&query);
 967 }
 968
 969 static void
 970 fctx_cancelqueries(fetchctx_t *fctx, isc_boolean_t no_response) {
 971         resquery_t *query, *next_query;
 972
 973         FCTXTRACE("cancelqueries");
 974
 975         for (query = ISC_LIST_HEAD(fctx->queries);
 976              query != NULL;
 977              query = next_query) {
 978                 next_query = ISC_LIST_NEXT(query, link);
 979                 fctx_cancelquery(&query, NULL, NULL, no_response);
 980         }
 981 }
 982
 983 static void
 984 fctx_cleanupfinds(fetchctx_t *fctx) {
 985         dns_adbfind_t *find, *next_find;
 986
 987         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
 988
 989         for (find = ISC_LIST_HEAD(fctx->finds);
 990              find != NULL;
 991              find = next_find) {
 992                 next_find = ISC_LIST_NEXT(find, publink);
 993                 ISC_LIST_UNLINK(fctx->finds, find, publink);
 994                 dns_adb_destroyfind(&find);
 995         }
 996         fctx->find = NULL;
 997 }
 998
 999 static void
1000 fctx_cleanupaltfinds(fetchctx_t *fctx) {
1001         dns_adbfind_t *find, *next_find;
1002
1003         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
1004
1005         for (find = ISC_LIST_HEAD(fctx->altfinds);
1006              find != NULL;
1007              find = next_find) {
1008                 next_find = ISC_LIST_NEXT(find, publink);
1009                 ISC_LIST_UNLINK(fctx->altfinds, find, publink);
1010                 dns_adb_destroyfind(&find);
1011         }
1012         fctx->altfind = NULL;
1013 }
1014
1015 static void
1016 fctx_cleanupforwaddrs(fetchctx_t *fctx) {
1017         dns_adbaddrinfo_t *addr, *next_addr;
1018
1019         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
1020
1021         for (addr = ISC_LIST_HEAD(fctx->forwaddrs);
1022              addr != NULL;
1023              addr = next_addr) {
1024                 next_addr = ISC_LIST_NEXT(addr, publink);
1025                 ISC_LIST_UNLINK(fctx->forwaddrs, addr, publink);
1026                 dns_adb_freeaddrinfo(fctx->adb, &addr);
1027         }
1028 }
1029
1030 static void
1031 fctx_cleanupaltaddrs(fetchctx_t *fctx) {
1032         dns_adbaddrinfo_t *addr, *next_addr;
1033
1034         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
1035
1036         for (addr = ISC_LIST_HEAD(fctx->altaddrs);
1037              addr != NULL;
1038              addr = next_addr) {
1039                 next_addr = ISC_LIST_NEXT(addr, publink);
1040                 ISC_LIST_UNLINK(fctx->altaddrs, addr, publink);
1041                 dns_adb_freeaddrinfo(fctx->adb, &addr);
1042         }
1043 }
1044
1045 static inline void
1046 fctx_stopeverything(fetchctx_t *fctx, isc_boolean_t no_response) {
1047         FCTXTRACE("stopeverything");
1048         fctx_cancelqueries(fctx, no_response);
1049         fctx_cleanupfinds(fctx);
1050         fctx_cleanupaltfinds(fctx);
1051         fctx_cleanupforwaddrs(fctx);
1052         fctx_cleanupaltaddrs(fctx);
1053         fctx_stoptimer(fctx);
1054 }
1055
1056 static inline void
1057 fctx_sendevents(fetchctx_t *fctx, isc_result_t result, int line) {
1058         dns_fetchevent_t *event, *next_event;
1059         isc_task_t *task;
1060         unsigned int count = 0;
1061         isc_interval_t i;
1062         isc_boolean_t logit = ISC_FALSE;
1063         isc_time_t now;
1064         unsigned int old_spillat;
1065         unsigned int new_spillat = 0;   /* initialized to silence
1066                                            compiler warnings */
1067
1068         /*
1069          * Caller must be holding the appropriate bucket lock.
1070          */
1071         REQUIRE(fctx->state == fetchstate_done);
1072
1073         FCTXTRACE("sendevents");
1074
1075         /*
1076          * Keep some record of fetch result for logging later (if required).
1077          */
1078         fctx->result = result;
1079         fctx->exitline = line;
1080         TIME_NOW(&now);
1081         fctx->duration = isc_time_microdiff(&now, &fctx->start);
1082
1083         for (event = ISC_LIST_HEAD(fctx->events);
1084              event != NULL;
1085              event = next_event) {
1086                 next_event = ISC_LIST_NEXT(event, ev_link);
1087                 ISC_LIST_UNLINK(fctx->events, event, ev_link);
1088                 task = event->ev_sender;
1089                 event->ev_sender = fctx;
1090                 event->vresult = fctx->vresult;
1091                 if (!HAVE_ANSWER(fctx))
1092                         event->result = result;
1093
1094                 INSIST(result != ISC_R_SUCCESS ||
1095                        dns_rdataset_isassociated(event->rdataset) ||
1096                        fctx->type == dns_rdatatype_any ||
1097                        fctx->type == dns_rdatatype_rrsig ||
1098                        fctx->type == dns_rdatatype_sig);
1099
1100                 /*
1101                  * Negative results must be indicated in event->result.
1102                  */
1103                 if (dns_rdataset_isassociated(event->rdataset) &&
1104                     NEGATIVE(event->rdataset)) {
1105                         INSIST(event->result == DNS_R_NCACHENXDOMAIN ||
1106                                event->result == DNS_R_NCACHENXRRSET);
1107                 }
1108
1109                 event->qtotal = fctx->totalqueries;
1110                 isc_task_sendanddetach(&task, ISC_EVENT_PTR(&event));
1111                 count++;
1112         }
1113
1114         if ((fctx->attributes & FCTX_ATTR_HAVEANSWER) != 0 &&
1115             fctx->spilled &&
1116             (count < fctx->res->spillatmax || fctx->res->spillatmax == 0)) {
1117                 LOCK(&fctx->res->lock);
1118                 if (count == fctx->res->spillat && !fctx->res->exiting) {
1119                         old_spillat = fctx->res->spillat;
1120                         fctx->res->spillat += 5;
1121                         if (fctx->res->spillat > fctx->res->spillatmax &&
1122                             fctx->res->spillatmax != 0)
1123                                 fctx->res->spillat = fctx->res->spillatmax;
1124                         new_spillat = fctx->res->spillat;
1125                         if (new_spillat != old_spillat) {
1126                                 logit = ISC_TRUE;
1127                         }
1128                         isc_interval_set(&i, 20 * 60, 0);
1129                         result = isc_timer_reset(fctx->res->spillattimer,
1130                                                  isc_timertype_ticker, NULL,
1131                                                  &i, ISC_TRUE);
1132                         RUNTIME_CHECK(result == ISC_R_SUCCESS);
1133                 }
1134                 UNLOCK(&fctx->res->lock);
1135                 if (logit)
1136                         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
1137                                       DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
1138                                       "clients-per-query increased to %u",
1139                                       new_spillat);
1140         }
1141 }
1142
1143 static inline void
1144 log_edns(fetchctx_t *fctx) {
1145         char domainbuf[DNS_NAME_FORMATSIZE];
1146
1147         if (fctx->reason == NULL)
1148                 return;
1149
1150         /*
1151          * We do not know if fctx->domain is the actual domain the record
1152          * lives in or a parent domain so we have a '?' after it.
1153          */
1154         dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
1155         isc_log_write(dns_lctx, DNS_LOGCATEGORY_EDNS_DISABLED,
1156                       DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
1157                       "success resolving '%s' (in '%s'?) after %s",
1158                       fctx->info, domainbuf, fctx->reason);
1159
1160         fctx->reason = NULL;
1161 }
1162
1163 static void
1164 fctx_done(fetchctx_t *fctx, isc_result_t result, int line) {
1165         dns_resolver_t *res;
1166         isc_boolean_t no_response;
1167
1168         REQUIRE(line >= 0);
1169
1170         FCTXTRACE("done");
1171
1172         res = fctx->res;
1173
1174         if (result == ISC_R_SUCCESS) {
1175                 /*%
1176                  * Log any deferred EDNS timeout messages.
1177                  */
1178                 log_edns(fctx);
1179                 no_response = ISC_TRUE;
1180          } else
1181                 no_response = ISC_FALSE;
1182
1183         fctx->reason = NULL;
1184         fctx_stopeverything(fctx, no_response);
1185
1186         LOCK(&res->buckets[fctx->bucketnum].lock);
1187
1188         fctx->state = fetchstate_done;
1189         fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
1190         fctx_sendevents(fctx, result, line);
1191
1192         UNLOCK(&res->buckets[fctx->bucketnum].lock);
1193 }
1194
1195 static void
1196 process_sendevent(resquery_t *query, isc_event_t *event) {
1197         isc_socketevent_t *sevent = (isc_socketevent_t *)event;
1198         isc_boolean_t retry = ISC_FALSE;
1199         isc_result_t result;
1200         fetchctx_t *fctx;
1201
1202         fctx = query->fctx;
1203
1204         if (RESQUERY_CANCELED(query)) {
1205                 if (query->sends == 0 && query->connects == 0) {
1206                         /*
1207                          * This query was canceled while the
1208                          * isc_socket_sendto/connect() was in progress.
1209                          */
1210                         if (query->tcpsocket != NULL)
1211                                 isc_socket_detach(&query->tcpsocket);
1212                         resquery_destroy(&query);
1213                 }
1214         } else {
1215                 switch (sevent->result) {
1216                 case ISC_R_SUCCESS:
1217                         break;
1218
1219                 case ISC_R_HOSTUNREACH:
1220                 case ISC_R_NETUNREACH:
1221                 case ISC_R_NOPERM:
1222                 case ISC_R_ADDRNOTAVAIL:
1223                 case ISC_R_CONNREFUSED:
1224
1225                         /*
1226                          * No route to remote.
1227                          */
1228                         add_bad(fctx, query->addrinfo, sevent->result,
1229                                 badns_unreachable);
1230                         fctx_cancelquery(&query, NULL, NULL, ISC_TRUE);
1231                         retry = ISC_TRUE;
1232                         break;
1233
1234                 default:
1235                         fctx_cancelquery(&query, NULL, NULL, ISC_FALSE);
1236                         break;
1237                 }
1238         }
1239
1240         if (event->ev_type == ISC_SOCKEVENT_CONNECT)
1241                 isc_event_free(&event);
1242
1243         if (retry) {
1244                 /*
1245                  * Behave as if the idle timer has expired.  For TCP
1246                  * this may not actually reflect the latest timer.
1247                  */
1248                 fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
1249                 result = fctx_stopidletimer(fctx);
1250                 if (result != ISC_R_SUCCESS)
1251                         fctx_done(fctx, result, __LINE__);
1252                 else
1253                         fctx_try(fctx, ISC_TRUE, ISC_FALSE);
1254         }
1255 }
1256
1257 static void
1258 resquery_udpconnected(isc_task_t *task, isc_event_t *event) {
1259         resquery_t *query = event->ev_arg;
1260
1261         REQUIRE(event->ev_type == ISC_SOCKEVENT_CONNECT);
1262
1263         QTRACE("udpconnected");
1264
1265         UNUSED(task);
1266
1267         INSIST(RESQUERY_CONNECTING(query));
1268
1269         query->connects--;
1270
1271         process_sendevent(query, event);
1272 }
1273
1274 static void
1275 resquery_senddone(isc_task_t *task, isc_event_t *event) {
1276         resquery_t *query = event->ev_arg;
1277
1278         REQUIRE(event->ev_type == ISC_SOCKEVENT_SENDDONE);
1279
1280         QTRACE("senddone");
1281
1282         /*
1283          * XXXRTH
1284          *
1285          * Currently we don't wait for the senddone event before retrying
1286          * a query.  This means that if we get really behind, we may end
1287          * up doing extra work!
1288          */
1289
1290         UNUSED(task);
1291
1292         INSIST(RESQUERY_SENDING(query));
1293
1294         query->sends--;
1295
1296         process_sendevent(query, event);
1297 }
1298
1299 static inline isc_result_t
1300 fctx_addopt(dns_message_t *message, unsigned int version,
1301             isc_uint16_t udpsize, dns_ednsopt_t *ednsopts, size_t count)
1302 {
1303         dns_rdataset_t *rdataset = NULL;
1304         isc_result_t result;
1305
1306         result = dns_message_buildopt(message, &rdataset, version, udpsize,
1307                                       DNS_MESSAGEEXTFLAG_DO, ednsopts, count);
1308         if (result != ISC_R_SUCCESS)
1309                 return (result);
1310         return (dns_message_setopt(message, rdataset));
1311 }
1312
1313 static inline void
1314 fctx_setretryinterval(fetchctx_t *fctx, unsigned int rtt) {
1315         unsigned int seconds;
1316         unsigned int us;
1317
1318         /*
1319          * We retry every .8 seconds the first two times through the address
1320          * list, and then we do exponential back-off.
1321          */
1322         if (fctx->restarts < 3)
1323                 us = 800000;
1324         else
1325                 us = (800000 << (fctx->restarts - 2));
1326
1327         /*
1328          * Add a fudge factor to the expected rtt based on the current
1329          * estimate.
1330          */
1331         if (rtt < 50000)
1332                 rtt += 50000;
1333         else if (rtt < 100000)
1334                 rtt += 100000;
1335         else
1336                 rtt += 200000;
1337
1338         /*
1339          * Always wait for at least the expected rtt.
1340          */
1341         if (us < rtt)
1342                 us = rtt;
1343
1344         /*
1345          * But don't ever wait for more than 10 seconds.
1346          */
1347         if (us > MAX_SINGLE_QUERY_TIMEOUT_US)
1348                 us = MAX_SINGLE_QUERY_TIMEOUT_US;
1349
1350         seconds = us / US_PER_SEC;
1351         us -= seconds * US_PER_SEC;
1352         isc_interval_set(&fctx->interval, seconds, us * 1000);
1353 }
1354
1355 static isc_result_t
1356 fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
1357            unsigned int options)
1358 {
1359         dns_resolver_t *res;
1360         isc_task_t *task;
1361         isc_result_t result;
1362         resquery_t *query;
1363         isc_sockaddr_t addr;
1364         isc_boolean_t have_addr = ISC_FALSE;
1365         unsigned int srtt;
1366
1367         FCTXTRACE("query");
1368
1369         res = fctx->res;
1370         task = res->buckets[fctx->bucketnum].task;
1371
1372         srtt = addrinfo->srtt;
1373
1374         /*
1375          * A forwarder needs to make multiple queries. Give it at least
1376          * a second to do these in.
1377          */
1378         if (ISFORWARDER(addrinfo) && srtt < 1000000)
1379                 srtt = 1000000;
1380
1381         fctx_setretryinterval(fctx, srtt);
1382         result = fctx_startidletimer(fctx, &fctx->interval);
1383         if (result != ISC_R_SUCCESS)
1384                 return (result);
1385
1386         INSIST(ISC_LIST_EMPTY(fctx->validators));
1387
1388         dns_message_reset(fctx->rmessage, DNS_MESSAGE_INTENTPARSE);
1389
1390         query = isc_mem_get(fctx->mctx, sizeof(*query));
1391         if (query == NULL) {
1392                 result = ISC_R_NOMEMORY;
1393                 goto stop_idle_timer;
1394         }
1395         query->mctx = fctx->mctx;
1396         query->options = options;
1397         query->attributes = 0;
1398         query->sends = 0;
1399         query->connects = 0;
1400         /*
1401          * Note that the caller MUST guarantee that 'addrinfo' will remain
1402          * valid until this query is canceled.
1403          */
1404         query->addrinfo = addrinfo;
1405         TIME_NOW(&query->start);
1406
1407         /*
1408          * If this is a TCP query, then we need to make a socket and
1409          * a dispatch for it here.  Otherwise we use the resolver's
1410          * shared dispatch.
1411          */
1412         query->dispatchmgr = res->dispatchmgr;
1413         query->dispatch = NULL;
1414         query->exclusivesocket = ISC_FALSE;
1415         query->tcpsocket = NULL;
1416         if (res->view->peers != NULL) {
1417                 dns_peer_t *peer = NULL;
1418                 isc_netaddr_t dstip;
1419                 isc_netaddr_fromsockaddr(&dstip, &addrinfo->sockaddr);
1420                 result = dns_peerlist_peerbyaddr(res->view->peers,
1421                                                  &dstip, &peer);
1422                 if (result == ISC_R_SUCCESS) {
1423                         result = dns_peer_getquerysource(peer, &addr);
1424                         if (result == ISC_R_SUCCESS)
1425                                 have_addr = ISC_TRUE;
1426                 }
1427         }
1428
1429         if ((query->options & DNS_FETCHOPT_TCP) != 0) {
1430                 int pf;
1431
1432                 pf = isc_sockaddr_pf(&addrinfo->sockaddr);
1433                 if (!have_addr) {
1434                         switch (pf) {
1435                         case PF_INET:
1436                                 result = dns_dispatch_getlocaladdress(
1437                                               res->dispatches4->dispatches[0],
1438                                               &addr);
1439                                 break;
1440                         case PF_INET6:
1441                                 result = dns_dispatch_getlocaladdress(
1442                                               res->dispatches6->dispatches[0],
1443                                               &addr);
1444                                 break;
1445                         default:
1446                                 result = ISC_R_NOTIMPLEMENTED;
1447                                 break;
1448                         }
1449                         if (result != ISC_R_SUCCESS)
1450                                 goto cleanup_query;
1451                 }
1452                 isc_sockaddr_setport(&addr, 0);
1453
1454                 result = isc_socket_create(res->socketmgr, pf,
1455                                            isc_sockettype_tcp,
1456                                            &query->tcpsocket);
1457                 if (result != ISC_R_SUCCESS)
1458                         goto cleanup_query;
1459
1460 #ifndef BROKEN_TCP_BIND_BEFORE_CONNECT
1461                 result = isc_socket_bind(query->tcpsocket, &addr, 0);
1462                 if (result != ISC_R_SUCCESS)
1463                         goto cleanup_socket;
1464 #endif
1465
1466                 /*
1467                  * A dispatch will be created once the connect succeeds.
1468                  */
1469         } else {
1470                 if (have_addr) {
1471                         unsigned int attrs, attrmask;
1472                         attrs = DNS_DISPATCHATTR_UDP;
1473                         switch (isc_sockaddr_pf(&addr)) {
1474                         case AF_INET:
1475                                 attrs |= DNS_DISPATCHATTR_IPV4;
1476                                 break;
1477                         case AF_INET6:
1478                                 attrs |= DNS_DISPATCHATTR_IPV6;
1479                                 break;
1480                         default:
1481                                 result = ISC_R_NOTIMPLEMENTED;
1482                                 goto cleanup_query;
1483                         }
1484                         attrmask = DNS_DISPATCHATTR_UDP;
1485                         attrmask |= DNS_DISPATCHATTR_TCP;
1486                         attrmask |= DNS_DISPATCHATTR_IPV4;
1487                         attrmask |= DNS_DISPATCHATTR_IPV6;
1488                         result = dns_dispatch_getudp(res->dispatchmgr,
1489                                                      res->socketmgr,
1490                                                      res->taskmgr, &addr,
1491                                                      4096, 1000, 32768, 16411,
1492                                                      16433, attrs, attrmask,
1493                                                      &query->dispatch);
1494                         if (result != ISC_R_SUCCESS)
1495                                 goto cleanup_query;
1496                 } else {
1497                         switch (isc_sockaddr_pf(&addrinfo->sockaddr)) {
1498                         case PF_INET:
1499                                 dns_dispatch_attach(
1500                                     dns_resolver_dispatchv4(res),
1501                                     &query->dispatch);
1502                                 query->exclusivesocket = res->exclusivev4;
1503                                 break;
1504                         case PF_INET6:
1505                                 dns_dispatch_attach(
1506                                     dns_resolver_dispatchv6(res),
1507                                     &query->dispatch);
1508                                 query->exclusivesocket = res->exclusivev6;
1509                                 break;
1510                         default:
1511                                 result = ISC_R_NOTIMPLEMENTED;
1512                                 goto cleanup_query;
1513                         }
1514                 }
1515                 /*
1516                  * We should always have a valid dispatcher here.  If we
1517                  * don't support a protocol family, then its dispatcher
1518                  * will be NULL, but we shouldn't be finding addresses for
1519                  * protocol types we don't support, so the dispatcher
1520                  * we found should never be NULL.
1521                  */
1522                 INSIST(query->dispatch != NULL);
1523         }
1524
1525         query->dispentry = NULL;
1526         query->fctx = fctx;
1527         query->tsig = NULL;
1528         query->tsigkey = NULL;
1529         ISC_LINK_INIT(query, link);
1530         query->magic = QUERY_MAGIC;
1531
1532         if ((query->options & DNS_FETCHOPT_TCP) != 0) {
1533                 /*
1534                  * Connect to the remote server.
1535                  *
1536                  * XXXRTH  Should we attach to the socket?
1537                  */
1538                 result = isc_socket_connect(query->tcpsocket,
1539                                             &addrinfo->sockaddr, task,
1540                                             resquery_connected, query);
1541                 if (result != ISC_R_SUCCESS)
1542                         goto cleanup_socket;
1543                 query->connects++;
1544                 QTRACE("connecting via TCP");
1545         } else {
1546                 result = resquery_send(query);
1547                 if (result != ISC_R_SUCCESS)
1548                         goto cleanup_dispatch;
1549         }
1550
1551         fctx->querysent++;
1552         fctx->totalqueries++;
1553
1554         ISC_LIST_APPEND(fctx->queries, query, link);
1555         query->fctx->nqueries++;
1556         if (isc_sockaddr_pf(&addrinfo->sockaddr) == PF_INET)
1557                 inc_stats(res, dns_resstatscounter_queryv4);
1558         else
1559                 inc_stats(res, dns_resstatscounter_queryv6);
1560         if (res->view->resquerystats != NULL)
1561                 dns_rdatatypestats_increment(res->view->resquerystats,
1562                                              fctx->type);
1563
1564         return (ISC_R_SUCCESS);
1565
1566  cleanup_socket:
1567         isc_socket_detach(&query->tcpsocket);
1568
1569  cleanup_dispatch:
1570         if (query->dispatch != NULL)
1571                 dns_dispatch_detach(&query->dispatch);
1572
1573  cleanup_query:
1574         if (query->connects == 0) {
1575                 query->magic = 0;
1576                 isc_mem_put(fctx->mctx, query, sizeof(*query));
1577         }
1578
1579  stop_idle_timer:
1580         RUNTIME_CHECK(fctx_stopidletimer(fctx) == ISC_R_SUCCESS);
1581
1582         return (result);
1583 }
1584
1585 static isc_boolean_t
1586 bad_edns(fetchctx_t *fctx, isc_sockaddr_t *address) {
1587         isc_sockaddr_t *sa;
1588
1589         for (sa = ISC_LIST_HEAD(fctx->bad_edns);
1590              sa != NULL;
1591              sa = ISC_LIST_NEXT(sa, link)) {
1592                 if (isc_sockaddr_equal(sa, address))
1593                         return (ISC_TRUE);
1594         }
1595
1596         return (ISC_FALSE);
1597 }
1598
1599 static void
1600 add_bad_edns(fetchctx_t *fctx, isc_sockaddr_t *address) {
1601         isc_sockaddr_t *sa;
1602
1603         if (bad_edns(fctx, address))
1604                 return;
1605
1606         sa = isc_mem_get(fctx->mctx, sizeof(*sa));
1607         if (sa == NULL)
1608                 return;
1609
1610         *sa = *address;
1611         ISC_LIST_INITANDAPPEND(fctx->bad_edns, sa, link);
1612 }
1613
1614 static isc_boolean_t
1615 triededns(fetchctx_t *fctx, isc_sockaddr_t *address) {
1616         isc_sockaddr_t *sa;
1617
1618         for (sa = ISC_LIST_HEAD(fctx->edns);
1619              sa != NULL;
1620              sa = ISC_LIST_NEXT(sa, link)) {
1621                 if (isc_sockaddr_equal(sa, address))
1622                         return (ISC_TRUE);
1623         }
1624
1625         return (ISC_FALSE);
1626 }
1627
1628 static void
1629 add_triededns(fetchctx_t *fctx, isc_sockaddr_t *address) {
1630         isc_sockaddr_t *sa;
1631
1632         if (triededns(fctx, address))
1633                 return;
1634
1635         sa = isc_mem_get(fctx->mctx, sizeof(*sa));
1636         if (sa == NULL)
1637                 return;
1638
1639         *sa = *address;
1640         ISC_LIST_INITANDAPPEND(fctx->edns, sa, link);
1641 }
1642
1643 static isc_boolean_t
1644 triededns512(fetchctx_t *fctx, isc_sockaddr_t *address) {
1645         isc_sockaddr_t *sa;
1646
1647         for (sa = ISC_LIST_HEAD(fctx->edns512);
1648              sa != NULL;
1649              sa = ISC_LIST_NEXT(sa, link)) {
1650                 if (isc_sockaddr_equal(sa, address))
1651                         return (ISC_TRUE);
1652         }
1653
1654         return (ISC_FALSE);
1655 }
1656
1657 static void
1658 add_triededns512(fetchctx_t *fctx, isc_sockaddr_t *address) {
1659         isc_sockaddr_t *sa;
1660
1661         if (triededns512(fctx, address))
1662                 return;
1663
1664         sa = isc_mem_get(fctx->mctx, sizeof(*sa));
1665         if (sa == NULL)
1666                 return;
1667
1668         *sa = *address;
1669         ISC_LIST_INITANDAPPEND(fctx->edns512, sa, link);
1670 }
1671
1672 static isc_result_t
1673 resquery_send(resquery_t *query) {
1674         fetchctx_t *fctx;
1675         isc_result_t result;
1676         dns_name_t *qname = NULL;
1677         dns_rdataset_t *qrdataset = NULL;
1678         isc_region_t r;
1679         dns_resolver_t *res;
1680         isc_task_t *task;
1681         isc_socket_t *socket;
1682         isc_buffer_t tcpbuffer;
1683         isc_sockaddr_t *address;
1684         isc_buffer_t *buffer;
1685         isc_netaddr_t ipaddr;
1686         dns_tsigkey_t *tsigkey = NULL;
1687         dns_peer_t *peer = NULL;
1688         isc_boolean_t useedns;
1689         dns_compress_t cctx;
1690         isc_boolean_t cleanup_cctx = ISC_FALSE;
1691         isc_boolean_t secure_domain;
1692         isc_boolean_t connecting = ISC_FALSE;
1693         dns_ednsopt_t ednsopts[EDNSOPTS];
1694         unsigned ednsopt = 0;
1695
1696         fctx = query->fctx;
1697         QTRACE("send");
1698
1699         res = fctx->res;
1700         task = res->buckets[fctx->bucketnum].task;
1701         address = NULL;
1702
1703         if ((query->options & DNS_FETCHOPT_TCP) != 0) {
1704                 /*
1705                  * Reserve space for the TCP message length.
1706                  */
1707                 isc_buffer_init(&tcpbuffer, query->data, sizeof(query->data));
1708                 isc_buffer_init(&query->buffer, query->data + 2,
1709                                 sizeof(query->data) - 2);
1710                 buffer = &tcpbuffer;
1711         } else {
1712                 isc_buffer_init(&query->buffer, query->data,
1713                                 sizeof(query->data));
1714                 buffer = &query->buffer;
1715         }
1716
1717         result = dns_message_gettempname(fctx->qmessage, &qname);
1718         if (result != ISC_R_SUCCESS)
1719                 goto cleanup_temps;
1720         result = dns_message_gettemprdataset(fctx->qmessage, &qrdataset);
1721         if (result != ISC_R_SUCCESS)
1722                 goto cleanup_temps;
1723
1724         /*
1725          * Get a query id from the dispatch.
1726          */
1727         result = dns_dispatch_addresponse2(query->dispatch,
1728                                            &query->addrinfo->sockaddr,
1729                                            task,
1730                                            resquery_response,
1731                                            query,
1732                                            &query->id,
1733                                            &query->dispentry,
1734                                            res->socketmgr);
1735         if (result != ISC_R_SUCCESS)
1736                 goto cleanup_temps;
1737
1738         fctx->qmessage->opcode = dns_opcode_query;
1739
1740         /*
1741          * Set up question.
1742          */
1743         dns_name_init(qname, NULL);
1744         dns_name_clone(&fctx->name, qname);
1745         dns_rdataset_init(qrdataset);
1746         dns_rdataset_makequestion(qrdataset, res->rdclass, fctx->type);
1747         ISC_LIST_APPEND(qname->list, qrdataset, link);
1748         dns_message_addname(fctx->qmessage, qname, DNS_SECTION_QUESTION);
1749         qname = NULL;
1750         qrdataset = NULL;
1751
1752         /*
1753          * Set RD if the client has requested that we do a recursive query,
1754          * or if we're sending to a forwarder.
1755          */
1756         if ((query->options & DNS_FETCHOPT_RECURSIVE) != 0 ||
1757             ISFORWARDER(query->addrinfo))
1758                 fctx->qmessage->flags |= DNS_MESSAGEFLAG_RD;
1759
1760         /*
1761          * Set CD if the client says don't validate or the question is
1762          * under a secure entry point.
1763          */
1764         if ((query->options & DNS_FETCHOPT_NOVALIDATE) != 0) {
1765                 fctx->qmessage->flags |= DNS_MESSAGEFLAG_CD;
1766         } else if (res->view->enablevalidation) {
1767                 result = dns_view_issecuredomain(res->view, &fctx->name,
1768                                                  &secure_domain);
1769                 if (result != ISC_R_SUCCESS)
1770                         secure_domain = ISC_FALSE;
1771                 if (res->view->dlv != NULL)
1772                         secure_domain = ISC_TRUE;
1773                 if (secure_domain)
1774                         fctx->qmessage->flags |= DNS_MESSAGEFLAG_CD;
1775         }
1776
1777         /*
1778          * We don't have to set opcode because it defaults to query.
1779          */
1780         fctx->qmessage->id = query->id;
1781
1782         /*
1783          * Convert the question to wire format.
1784          */
1785         result = dns_compress_init(&cctx, -1, fctx->res->mctx);
1786         if (result != ISC_R_SUCCESS)
1787                 goto cleanup_message;
1788         cleanup_cctx = ISC_TRUE;
1789
1790         result = dns_message_renderbegin(fctx->qmessage, &cctx,
1791                                          &query->buffer);
1792         if (result != ISC_R_SUCCESS)
1793                 goto cleanup_message;
1794
1795         result = dns_message_rendersection(fctx->qmessage,
1796                                            DNS_SECTION_QUESTION, 0);
1797         if (result != ISC_R_SUCCESS)
1798                 goto cleanup_message;
1799
1800         peer = NULL;
1801         isc_netaddr_fromsockaddr(&ipaddr, &query->addrinfo->sockaddr);
1802         (void) dns_peerlist_peerbyaddr(fctx->res->view->peers, &ipaddr, &peer);
1803
1804         /*
1805          * The ADB does not know about servers with "edns no".  Check this,
1806          * and then inform the ADB for future use.
1807          */
1808         if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) == 0 &&
1809             peer != NULL &&
1810             dns_peer_getsupportedns(peer, &useedns) == ISC_R_SUCCESS &&
1811             !useedns)
1812         {
1813                 query->options |= DNS_FETCHOPT_NOEDNS0;
1814                 dns_adb_changeflags(fctx->adb, query->addrinfo,
1815                                     DNS_FETCHOPT_NOEDNS0,
1816                                     DNS_FETCHOPT_NOEDNS0);
1817         }
1818
1819         /* Sync NOEDNS0 flag in addrinfo->flags and options now. */
1820         if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) != 0)
1821                 query->options |= DNS_FETCHOPT_NOEDNS0;
1822
1823         /*
1824          * Handle timeouts by reducing the UDP response size to 512 bytes
1825          * then if that doesn't work disabling EDNS (includes DO) and CD.
1826          *
1827          * These timeout can be due to:
1828          *      * broken nameservers that don't respond to EDNS queries.
1829          *      * broken/misconfigured firewalls and NAT implementations
1830          *        that don't handle IP fragmentation.
1831          *      * broken/misconfigured firewalls that don't handle responses
1832          *        greater than 512 bytes.
1833          *      * broken/misconfigured firewalls that don't handle EDNS, DO
1834          *        or CD.
1835          *      * packet loss / link outage.
1836          */
1837         if (fctx->timeout) {
1838                 if ((triededns512(fctx, &query->addrinfo->sockaddr) ||
1839                      fctx->timeouts >= (MAX_EDNS0_TIMEOUTS * 2)) &&
1840                     (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
1841                         query->options |= DNS_FETCHOPT_NOEDNS0;
1842                         fctx->reason = "disabling EDNS";
1843                 } else if ((triededns(fctx, &query->addrinfo->sockaddr) ||
1844                             fctx->timeouts >= MAX_EDNS0_TIMEOUTS) &&
1845                            (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
1846                         query->options |= DNS_FETCHOPT_EDNS512;
1847                         fctx->reason = "reducing the advertised EDNS UDP "
1848                                        "packet size to 512 octets";
1849                 }
1850                 fctx->timeout = ISC_FALSE;
1851         }
1852
1853         /*
1854          * Use EDNS0, unless the caller doesn't want it, or we know that
1855          * the remote server doesn't like it.
1856          */
1857         if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
1858                 if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) == 0) {
1859                         unsigned int version = 0;       /* Default version. */
1860                         unsigned int flags;
1861                         isc_uint16_t udpsize = res->udpsize;
1862                         isc_boolean_t reqnsid = res->view->requestnsid;
1863
1864                         flags = query->addrinfo->flags;
1865                         if ((flags & DNS_FETCHOPT_EDNSVERSIONSET) != 0) {
1866                                 version = flags & DNS_FETCHOPT_EDNSVERSIONMASK;
1867                                 version >>= DNS_FETCHOPT_EDNSVERSIONSHIFT;
1868                         }
1869                         if ((query->options & DNS_FETCHOPT_EDNS512) != 0)
1870                                 udpsize = 512;
1871                         else if (peer != NULL)
1872                                 (void)dns_peer_getudpsize(peer, &udpsize);
1873
1874                         /* request NSID for current view or peer? */
1875                         if (peer != NULL)
1876                                 (void) dns_peer_getrequestnsid(peer, &reqnsid);
1877                         if (reqnsid) {
1878                                 INSIST(ednsopt < EDNSOPTS);
1879                                 ednsopts[ednsopt].code = DNS_OPT_NSID;
1880                                 ednsopts[ednsopt].length = 0;
1881                                 ednsopts[ednsopt].value = NULL;
1882                                 ednsopt++;
1883                         }
1884                         result = fctx_addopt(fctx->qmessage, version,
1885                                              udpsize, ednsopts, ednsopt);
1886                         if (reqnsid && result == ISC_R_SUCCESS) {
1887                                 query->options |= DNS_FETCHOPT_WANTNSID;
1888                         } else if (result != ISC_R_SUCCESS) {
1889                                 /*
1890                                  * We couldn't add the OPT, but we'll press on.
1891                                  * We're not using EDNS0, so set the NOEDNS0
1892                                  * bit.
1893                                  */
1894                                 query->options |= DNS_FETCHOPT_NOEDNS0;
1895                         }
1896                 } else {
1897                         /*
1898                          * We know this server doesn't like EDNS0, so we
1899                          * won't use it.  Set the NOEDNS0 bit since we're
1900                          * not using EDNS0.
1901                          */
1902                         query->options |= DNS_FETCHOPT_NOEDNS0;
1903                 }
1904         }
1905
1906         /*
1907          * If we need EDNS0 to do this query and aren't using it, we lose.
1908          */
1909         if (NEEDEDNS0(fctx) && (query->options & DNS_FETCHOPT_NOEDNS0) != 0) {
1910                 result = DNS_R_SERVFAIL;
1911                 goto cleanup_message;
1912         }
1913
1914         if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0)
1915                 add_triededns(fctx, &query->addrinfo->sockaddr);
1916
1917         if ((query->options & DNS_FETCHOPT_EDNS512) != 0)
1918                 add_triededns512(fctx, &query->addrinfo->sockaddr);
1919
1920         /*
1921          * Clear CD if EDNS is not in use.
1922          */
1923         if ((query->options & DNS_FETCHOPT_NOEDNS0) != 0)
1924                 fctx->qmessage->flags &= ~DNS_MESSAGEFLAG_CD;
1925
1926         /*
1927          * Add TSIG record tailored to the current recipient.
1928          */
1929         result = dns_view_getpeertsig(fctx->res->view, &ipaddr, &tsigkey);
1930         if (result != ISC_R_SUCCESS && result != ISC_R_NOTFOUND)
1931                 goto cleanup_message;
1932
1933         if (tsigkey != NULL) {
1934                 result = dns_message_settsigkey(fctx->qmessage, tsigkey);
1935                 dns_tsigkey_detach(&tsigkey);
1936                 if (result != ISC_R_SUCCESS)
1937                         goto cleanup_message;
1938         }
1939
1940         result = dns_message_rendersection(fctx->qmessage,
1941                                            DNS_SECTION_ADDITIONAL, 0);
1942         if (result != ISC_R_SUCCESS)
1943                 goto cleanup_message;
1944
1945         result = dns_message_renderend(fctx->qmessage);
1946         if (result != ISC_R_SUCCESS)
1947                 goto cleanup_message;
1948
1949         dns_compress_invalidate(&cctx);
1950         cleanup_cctx = ISC_FALSE;
1951
1952         if (dns_message_gettsigkey(fctx->qmessage) != NULL) {
1953                 dns_tsigkey_attach(dns_message_gettsigkey(fctx->qmessage),
1954                                    &query->tsigkey);
1955                 result = dns_message_getquerytsig(fctx->qmessage,
1956                                                   fctx->res->mctx,
1957                                                   &query->tsig);
1958                 if (result != ISC_R_SUCCESS)
1959                         goto cleanup_message;
1960         }
1961
1962         /*
1963          * If using TCP, write the length of the message at the beginning
1964          * of the buffer.
1965          */
1966         if ((query->options & DNS_FETCHOPT_TCP) != 0) {
1967                 isc_buffer_usedregion(&query->buffer, &r);
1968                 isc_buffer_putuint16(&tcpbuffer, (isc_uint16_t)r.length);
1969                 isc_buffer_add(&tcpbuffer, r.length);
1970         }
1971
1972         /*
1973          * We're now done with the query message.
1974          */
1975         dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
1976
1977         if (query->exclusivesocket)
1978                 socket = dns_dispatch_getentrysocket(query->dispentry);
1979         else
1980                 socket = dns_dispatch_getsocket(query->dispatch);
1981         /*
1982          * Send the query!
1983          */
1984         if ((query->options & DNS_FETCHOPT_TCP) == 0) {
1985                 address = &query->addrinfo->sockaddr;
1986                 if (query->exclusivesocket) {
1987                         result = isc_socket_connect(socket, address, task,
1988                                                     resquery_udpconnected,
1989                                                     query);
1990                         if (result != ISC_R_SUCCESS)
1991                                 goto cleanup_message;
1992                         connecting = ISC_TRUE;
1993                         query->connects++;
1994                 }
1995         }
1996         isc_buffer_usedregion(buffer, &r);
1997
1998         /*
1999          * XXXRTH  Make sure we don't send to ourselves!  We should probably
2000          *              prune out these addresses when we get them from the ADB.
2001          */
2002         ISC_EVENT_INIT(&query->sendevent, sizeof(query->sendevent), 0, NULL,
2003                        ISC_SOCKEVENT_SENDDONE, resquery_senddone, query,
2004                        NULL, NULL, NULL);
2005         result = isc_socket_sendto2(socket, &r, task, address, NULL,
2006                                     &query->sendevent, 0);
2007         if (result != ISC_R_SUCCESS) {
2008                 if (connecting) {
2009                         /*
2010                          * This query is still connecting.
2011                          * Mark it as canceled so that it will just be
2012                          * cleaned up when the connected event is received.
2013                          * Keep fctx around until the event is processed.
2014                          */
2015                         query->fctx->nqueries++;
2016                         query->attributes |= RESQUERY_ATTR_CANCELED;
2017                 }
2018                 goto cleanup_message;
2019         }
2020
2021         query->sends++;
2022
2023         QTRACE("sent");
2024
2025         return (ISC_R_SUCCESS);
2026
2027  cleanup_message:
2028         if (cleanup_cctx)
2029                 dns_compress_invalidate(&cctx);
2030
2031         dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
2032
2033         /*
2034          * Stop the dispatcher from listening.
2035          */
2036         dns_dispatch_removeresponse(&query->dispentry, NULL);
2037
2038  cleanup_temps:
2039         if (qname != NULL)
2040                 dns_message_puttempname(fctx->qmessage, &qname);
2041         if (qrdataset != NULL)
2042                 dns_message_puttemprdataset(fctx->qmessage, &qrdataset);
2043
2044         return (result);
2045 }
2046
2047 static void
2048 resquery_connected(isc_task_t *task, isc_event_t *event) {
2049         isc_socketevent_t *sevent = (isc_socketevent_t *)event;
2050         resquery_t *query = event->ev_arg;
2051         isc_boolean_t retry = ISC_FALSE;
2052         isc_interval_t interval;
2053         isc_result_t result;
2054         unsigned int attrs;
2055         fetchctx_t *fctx;
2056
2057         REQUIRE(event->ev_type == ISC_SOCKEVENT_CONNECT);
2058         REQUIRE(VALID_QUERY(query));
2059
2060         QTRACE("connected");
2061
2062         UNUSED(task);
2063
2064         /*
2065          * XXXRTH
2066          *
2067          * Currently we don't wait for the connect event before retrying
2068          * a query.  This means that if we get really behind, we may end
2069          * up doing extra work!
2070          */
2071
2072         query->connects--;
2073         fctx = query->fctx;
2074
2075         if (RESQUERY_CANCELED(query)) {
2076                 /*
2077                  * This query was canceled while the connect() was in
2078                  * progress.
2079                  */
2080                 isc_socket_detach(&query->tcpsocket);
2081                 resquery_destroy(&query);
2082         } else {
2083                 switch (sevent->result) {
2084                 case ISC_R_SUCCESS:
2085
2086                         /*
2087                          * Extend the idle timer for TCP.  20 seconds
2088                          * should be long enough for a TCP connection to be
2089                          * established, a single DNS request to be sent,
2090                          * and the response received.
2091                          */
2092                         isc_interval_set(&interval, 20, 0);
2093                         result = fctx_startidletimer(query->fctx, &interval);
2094                         if (result != ISC_R_SUCCESS) {
2095                                 fctx_cancelquery(&query, NULL, NULL, ISC_FALSE);
2096                                 fctx_done(fctx, result, __LINE__);
2097                                 break;
2098                         }
2099                         /*
2100                          * We are connected.  Create a dispatcher and
2101                          * send the query.
2102                          */
2103                         attrs = 0;
2104                         attrs |= DNS_DISPATCHATTR_TCP;
2105                         attrs |= DNS_DISPATCHATTR_PRIVATE;
2106                         attrs |= DNS_DISPATCHATTR_CONNECTED;
2107                         if (isc_sockaddr_pf(&query->addrinfo->sockaddr) ==
2108                             AF_INET)
2109                                 attrs |= DNS_DISPATCHATTR_IPV4;
2110                         else
2111                                 attrs |= DNS_DISPATCHATTR_IPV6;
2112                         attrs |= DNS_DISPATCHATTR_MAKEQUERY;
2113
2114                         result = dns_dispatch_createtcp(query->dispatchmgr,
2115                                                      query->tcpsocket,
2116                                                      query->fctx->res->taskmgr,
2117                                                      4096, 2, 1, 1, 3, attrs,
2118                                                      &query->dispatch);
2119
2120                         /*
2121                          * Regardless of whether dns_dispatch_create()
2122                          * succeeded or not, we don't need our reference
2123                          * to the socket anymore.
2124                          */
2125                         isc_socket_detach(&query->tcpsocket);
2126
2127                         if (result == ISC_R_SUCCESS)
2128                                 result = resquery_send(query);
2129
2130                         if (result != ISC_R_SUCCESS) {
2131                                 fctx_cancelquery(&query, NULL, NULL, ISC_FALSE);
2132                                 fctx_done(fctx, result, __LINE__);
2133                         }
2134                         break;
2135
2136                 case ISC_R_NETUNREACH:
2137                 case ISC_R_HOSTUNREACH:
2138                 case ISC_R_CONNREFUSED:
2139                 case ISC_R_NOPERM:
2140                 case ISC_R_ADDRNOTAVAIL:
2141                 case ISC_R_CONNECTIONRESET:
2142                         /*
2143                          * No route to remote.
2144                          */
2145                         isc_socket_detach(&query->tcpsocket);
2146                         fctx_cancelquery(&query, NULL, NULL, ISC_TRUE);
2147                         retry = ISC_TRUE;
2148                         break;
2149
2150                 default:
2151                         isc_socket_detach(&query->tcpsocket);
2152                         fctx_cancelquery(&query, NULL, NULL, ISC_FALSE);
2153                         break;
2154                 }
2155         }
2156
2157         isc_event_free(&event);
2158
2159         if (retry) {
2160                 /*
2161                  * Behave as if the idle timer has expired.  For TCP
2162                  * connections this may not actually reflect the latest timer.
2163                  */
2164                 fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
2165                 result = fctx_stopidletimer(fctx);
2166                 if (result != ISC_R_SUCCESS)
2167                         fctx_done(fctx, result, __LINE__);
2168                 else
2169                         fctx_try(fctx, ISC_TRUE, ISC_FALSE);
2170         }
2171 }
2172
2173 static void
2174 fctx_finddone(isc_task_t *task, isc_event_t *event) {
2175         fetchctx_t *fctx;
2176         dns_adbfind_t *find;
2177         dns_resolver_t *res;
2178         isc_boolean_t want_try = ISC_FALSE;
2179         isc_boolean_t want_done = ISC_FALSE;
2180         isc_boolean_t bucket_empty = ISC_FALSE;
2181         unsigned int bucketnum;
2182         isc_boolean_t destroy = ISC_FALSE;
2183
2184         find = event->ev_sender;
2185         fctx = event->ev_arg;
2186         REQUIRE(VALID_FCTX(fctx));
2187         res = fctx->res;
2188
2189         UNUSED(task);
2190
2191         FCTXTRACE("finddone");
2192
2193         bucketnum = fctx->bucketnum;
2194         LOCK(&res->buckets[bucketnum].lock);
2195
2196         INSIST(fctx->pending > 0);
2197         fctx->pending--;
2198
2199         if (ADDRWAIT(fctx)) {
2200                 /*
2201                  * The fetch is waiting for a name to be found.
2202                  */
2203                 INSIST(!SHUTTINGDOWN(fctx));
2204                 fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
2205                 if (event->ev_type == DNS_EVENT_ADBMOREADDRESSES) {
2206                         want_try = ISC_TRUE;
2207                         fctx->totalqueries += find->qtotal;
2208                 } else {
2209                         fctx->findfail++;
2210                         if (fctx->pending == 0) {
2211                                 /*
2212                                  * We've got nothing else to wait for and don't
2213                                  * know the answer.  There's nothing to do but
2214                                  * fail the fctx.
2215                                  */
2216                                 want_done = ISC_TRUE;
2217                         }
2218                 }
2219         } else if (SHUTTINGDOWN(fctx) && fctx->pending == 0 &&
2220                    fctx->nqueries == 0 && ISC_LIST_EMPTY(fctx->validators)) {
2221
2222                 if (fctx->references == 0) {
2223                         bucket_empty = fctx_unlink(fctx);
2224                         destroy = ISC_TRUE;
2225                 }
2226         }
2227         UNLOCK(&res->buckets[bucketnum].lock);
2228
2229         isc_event_free(&event);
2230         dns_adb_destroyfind(&find);
2231
2232         if (want_try)
2233                 fctx_try(fctx, ISC_TRUE, ISC_FALSE);
2234         else if (want_done)
2235                 fctx_done(fctx, ISC_R_FAILURE, __LINE__);
2236         else if (destroy) {
2237                         fctx_destroy(fctx);
2238                 if (bucket_empty)
2239                         empty_bucket(res);
2240         }
2241 }
2242
2243
2244 static inline isc_boolean_t
2245 bad_server(fetchctx_t *fctx, isc_sockaddr_t *address) {
2246         isc_sockaddr_t *sa;
2247
2248         for (sa = ISC_LIST_HEAD(fctx->bad);
2249              sa != NULL;
2250              sa = ISC_LIST_NEXT(sa, link)) {
2251                 if (isc_sockaddr_equal(sa, address))
2252                         return (ISC_TRUE);
2253         }
2254
2255         return (ISC_FALSE);
2256 }
2257
2258 static inline isc_boolean_t
2259 mark_bad(fetchctx_t *fctx) {
2260         dns_adbfind_t *curr;
2261         dns_adbaddrinfo_t *addrinfo;
2262         isc_boolean_t all_bad = ISC_TRUE;
2263
2264         /*
2265          * Mark all known bad servers, so we don't try to talk to them
2266          * again.
2267          */
2268
2269         /*
2270          * Mark any bad nameservers.
2271          */
2272         for (curr = ISC_LIST_HEAD(fctx->finds);
2273              curr != NULL;
2274              curr = ISC_LIST_NEXT(curr, publink)) {
2275                 for (addrinfo = ISC_LIST_HEAD(curr->list);
2276                      addrinfo != NULL;
2277                      addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2278                         if (bad_server(fctx, &addrinfo->sockaddr))
2279                                 addrinfo->flags |= FCTX_ADDRINFO_MARK;
2280                         else
2281                                 all_bad = ISC_FALSE;
2282                 }
2283         }
2284
2285         /*
2286          * Mark any bad forwarders.
2287          */
2288         for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
2289              addrinfo != NULL;
2290              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2291                 if (bad_server(fctx, &addrinfo->sockaddr))
2292                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2293                 else
2294                         all_bad = ISC_FALSE;
2295         }
2296
2297         /*
2298          * Mark any bad alternates.
2299          */
2300         for (curr = ISC_LIST_HEAD(fctx->altfinds);
2301              curr != NULL;
2302              curr = ISC_LIST_NEXT(curr, publink)) {
2303                 for (addrinfo = ISC_LIST_HEAD(curr->list);
2304                      addrinfo != NULL;
2305                      addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2306                         if (bad_server(fctx, &addrinfo->sockaddr))
2307                                 addrinfo->flags |= FCTX_ADDRINFO_MARK;
2308                         else
2309                                 all_bad = ISC_FALSE;
2310                 }
2311         }
2312
2313         for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs);
2314              addrinfo != NULL;
2315              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2316                 if (bad_server(fctx, &addrinfo->sockaddr))
2317                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2318                 else
2319                         all_bad = ISC_FALSE;
2320         }
2321
2322         return (all_bad);
2323 }
2324
2325 static void
2326 add_bad(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo, isc_result_t reason,
2327         badnstype_t badtype)
2328 {
2329         char namebuf[DNS_NAME_FORMATSIZE];
2330         char addrbuf[ISC_SOCKADDR_FORMATSIZE];
2331         char classbuf[64];
2332         char typebuf[64];
2333         char code[64];
2334         isc_buffer_t b;
2335         isc_sockaddr_t *sa;
2336         const char *spc = "";
2337         isc_sockaddr_t *address = &addrinfo->sockaddr;
2338
2339         if (reason == DNS_R_LAME)
2340                 fctx->lamecount++;
2341         else {
2342                 switch (badtype) {
2343                 case badns_unreachable:
2344                         fctx->neterr++;
2345                         break;
2346                 case badns_response:
2347                         fctx->badresp++;
2348                         break;
2349                 case badns_validation:
2350                         break;  /* counted as 'valfail' */
2351                 }
2352         }
2353
2354         if (bad_server(fctx, address)) {
2355                 /*
2356                  * We already know this server is bad.
2357                  */
2358                 return;
2359         }
2360
2361         FCTXTRACE("add_bad");
2362
2363         sa = isc_mem_get(fctx->mctx, sizeof(*sa));
2364         if (sa == NULL)
2365                 return;
2366         *sa = *address;
2367         ISC_LIST_INITANDAPPEND(fctx->bad, sa, link);
2368
2369         if (reason == DNS_R_LAME)       /* already logged */
2370                 return;
2371
2372         if (reason == DNS_R_UNEXPECTEDRCODE &&
2373             fctx->rmessage->rcode == dns_rcode_servfail &&
2374             ISFORWARDER(addrinfo))
2375                 return;
2376
2377         if (reason == DNS_R_UNEXPECTEDRCODE) {
2378                 isc_buffer_init(&b, code, sizeof(code) - 1);
2379                 dns_rcode_totext(fctx->rmessage->rcode, &b);
2380                 code[isc_buffer_usedlength(&b)] = '\0';
2381                 spc = " ";
2382         } else if (reason == DNS_R_UNEXPECTEDOPCODE) {
2383                 isc_buffer_init(&b, code, sizeof(code) - 1);
2384                 dns_opcode_totext((dns_opcode_t)fctx->rmessage->opcode, &b);
2385                 code[isc_buffer_usedlength(&b)] = '\0';
2386                 spc = " ";
2387         } else {
2388                 code[0] = '\0';
2389         }
2390         dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
2391         dns_rdatatype_format(fctx->type, typebuf, sizeof(typebuf));
2392         dns_rdataclass_format(fctx->res->rdclass, classbuf, sizeof(classbuf));
2393         isc_sockaddr_format(address, addrbuf, sizeof(addrbuf));
2394         isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS,
2395                       DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
2396                       "error (%s%s%s) resolving '%s/%s/%s': %s",
2397                       dns_result_totext(reason), spc, code,
2398                       namebuf, typebuf, classbuf, addrbuf);
2399 }
2400
2401 /*
2402  * Sort addrinfo list by RTT.
2403  */
2404 static void
2405 sort_adbfind(dns_adbfind_t *find) {
2406         dns_adbaddrinfo_t *best, *curr;
2407         dns_adbaddrinfolist_t sorted;
2408
2409         /* Lame N^2 bubble sort. */
2410         ISC_LIST_INIT(sorted);
2411         while (!ISC_LIST_EMPTY(find->list)) {
2412                 best = ISC_LIST_HEAD(find->list);
2413                 curr = ISC_LIST_NEXT(best, publink);
2414                 while (curr != NULL) {
2415                         if (curr->srtt < best->srtt)
2416                                 best = curr;
2417                         curr = ISC_LIST_NEXT(curr, publink);
2418                 }
2419                 ISC_LIST_UNLINK(find->list, best, publink);
2420                 ISC_LIST_APPEND(sorted, best, publink);
2421         }
2422         find->list = sorted;
2423 }
2424
2425 /*
2426  * Sort a list of finds by server RTT.
2427  */
2428 static void
2429 sort_finds(dns_adbfindlist_t *findlist) {
2430         dns_adbfind_t *best, *curr;
2431         dns_adbfindlist_t sorted;
2432         dns_adbaddrinfo_t *addrinfo, *bestaddrinfo;
2433
2434         /* Sort each find's addrinfo list by SRTT. */
2435         for (curr = ISC_LIST_HEAD(*findlist);
2436              curr != NULL;
2437              curr = ISC_LIST_NEXT(curr, publink))
2438                 sort_adbfind(curr);
2439
2440         /* Lame N^2 bubble sort. */
2441         ISC_LIST_INIT(sorted);
2442         while (!ISC_LIST_EMPTY(*findlist)) {
2443                 best = ISC_LIST_HEAD(*findlist);
2444                 bestaddrinfo = ISC_LIST_HEAD(best->list);
2445                 INSIST(bestaddrinfo != NULL);
2446                 curr = ISC_LIST_NEXT(best, publink);
2447                 while (curr != NULL) {
2448                         addrinfo = ISC_LIST_HEAD(curr->list);
2449                         INSIST(addrinfo != NULL);
2450                         if (addrinfo->srtt < bestaddrinfo->srtt) {
2451                                 best = curr;
2452                                 bestaddrinfo = addrinfo;
2453                         }
2454                         curr = ISC_LIST_NEXT(curr, publink);
2455                 }
2456                 ISC_LIST_UNLINK(*findlist, best, publink);
2457                 ISC_LIST_APPEND(sorted, best, publink);
2458         }
2459         *findlist = sorted;
2460 }
2461
2462 static void
2463 findname(fetchctx_t *fctx, dns_name_t *name, in_port_t port,
2464          unsigned int options, unsigned int flags, isc_stdtime_t now,
2465          isc_boolean_t *need_alternate)
2466 {
2467         dns_adbaddrinfo_t *ai;
2468         dns_adbfind_t *find;
2469         dns_resolver_t *res;
2470         isc_boolean_t unshared;
2471         isc_result_t result;
2472
2473         res = fctx->res;
2474         unshared = ISC_TF((fctx->options & DNS_FETCHOPT_UNSHARED) != 0);
2475         /*
2476          * If this name is a subdomain of the query domain, tell
2477          * the ADB to start looking using zone/hint data. This keeps us
2478          * from getting stuck if the nameserver is beneath the zone cut
2479          * and we don't know its address (e.g. because the A record has
2480          * expired).
2481          */
2482         if (dns_name_issubdomain(name, &fctx->domain))
2483                 options |= DNS_ADBFIND_STARTATZONE;
2484         options |= DNS_ADBFIND_GLUEOK;
2485         options |= DNS_ADBFIND_HINTOK;
2486
2487         /*
2488          * See what we know about this address.
2489          */
2490         find = NULL;
2491         result = dns_adb_createfind2(fctx->adb,
2492                                      res->buckets[fctx->bucketnum].task,
2493                                      fctx_finddone, fctx, name,
2494                                      &fctx->name, fctx->type,
2495                                      options, now, NULL,
2496                                      res->view->dstport,
2497                                      fctx->depth + 1, &find);
2498         if (result != ISC_R_SUCCESS) {
2499                 if (result == DNS_R_ALIAS) {
2500                         /*
2501                          * XXXRTH  Follow the CNAME/DNAME chain?
2502                          */
2503                         dns_adb_destroyfind(&find);
2504                         fctx->adberr++;
2505                 }
2506         } else if (!ISC_LIST_EMPTY(find->list)) {
2507                 /*
2508                  * We have at least some of the addresses for the
2509                  * name.
2510                  */
2511                 INSIST((find->options & DNS_ADBFIND_WANTEVENT) == 0);
2512                 if (flags != 0 || port != 0) {
2513                         for (ai = ISC_LIST_HEAD(find->list);
2514                              ai != NULL;
2515                              ai = ISC_LIST_NEXT(ai, publink)) {
2516                                 ai->flags |= flags;
2517                                 if (port != 0)
2518                                         isc_sockaddr_setport(&ai->sockaddr,
2519                                                              port);
2520                         }
2521                 }
2522                 if ((flags & FCTX_ADDRINFO_FORWARDER) != 0)
2523                         ISC_LIST_APPEND(fctx->altfinds, find, publink);
2524                 else
2525                         ISC_LIST_APPEND(fctx->finds, find, publink);
2526         } else {
2527                 /*
2528                  * We don't know any of the addresses for this
2529                  * name.
2530                  */
2531                 if ((find->options & DNS_ADBFIND_WANTEVENT) != 0) {
2532                         /*
2533                          * We're looking for them and will get an
2534                          * event about it later.
2535                          */
2536                         fctx->pending++;
2537                         /*
2538                          * Bootstrap.
2539                          */
2540                         if (need_alternate != NULL &&
2541                             !*need_alternate && unshared &&
2542                             ((res->dispatches4 == NULL &&
2543                               find->result_v6 != DNS_R_NXDOMAIN) ||
2544                              (res->dispatches6 == NULL &&
2545                               find->result_v4 != DNS_R_NXDOMAIN)))
2546                                 *need_alternate = ISC_TRUE;
2547                 } else {
2548                         if ((find->options & DNS_ADBFIND_LAMEPRUNED) != 0)
2549                                 fctx->lamecount++; /* cached lame server */
2550                         else
2551                                 fctx->adberr++; /* unreachable server, etc. */
2552
2553                         /*
2554                          * If we know there are no addresses for
2555                          * the family we are using then try to add
2556                          * an alternative server.
2557                          */
2558                         if (need_alternate != NULL && !*need_alternate &&
2559                             ((res->dispatches4 == NULL &&
2560                               find->result_v6 == DNS_R_NXRRSET) ||
2561                              (res->dispatches6 == NULL &&
2562                               find->result_v4 == DNS_R_NXRRSET)))
2563                                 *need_alternate = ISC_TRUE;
2564                         dns_adb_destroyfind(&find);
2565                 }
2566         }
2567 }
2568
2569 static isc_boolean_t
2570 isstrictsubdomain(dns_name_t *name1, dns_name_t *name2) {
2571         int order;
2572         unsigned int nlabels;
2573         dns_namereln_t namereln;
2574
2575         namereln = dns_name_fullcompare(name1, name2, &order, &nlabels);
2576         return (ISC_TF(namereln == dns_namereln_subdomain));
2577 }
2578
2579 static isc_result_t
2580 fctx_getaddresses(fetchctx_t *fctx, isc_boolean_t badcache) {
2581         dns_rdata_t rdata = DNS_RDATA_INIT;
2582         isc_result_t result;
2583         dns_resolver_t *res;
2584         isc_stdtime_t now;
2585         unsigned int stdoptions = 0;
2586         isc_sockaddr_t *sa;
2587         dns_adbaddrinfo_t *ai;
2588         isc_boolean_t all_bad;
2589         dns_rdata_ns_t ns;
2590         isc_boolean_t need_alternate = ISC_FALSE;
2591
2592         FCTXTRACE("getaddresses");
2593
2594         /*
2595          * Don't pound on remote servers.  (Failsafe!)
2596          */
2597         fctx->restarts++;
2598         if (fctx->restarts > 10) {
2599                 FCTXTRACE("too many restarts");
2600                 return (DNS_R_SERVFAIL);
2601         }
2602
2603         res = fctx->res;
2604
2605         if (fctx->depth > res->maxdepth) {
2606                 FCTXTRACE("too much NS indirection");
2607                 return (DNS_R_SERVFAIL);
2608         }
2609
2610         /*
2611          * Forwarders.
2612          */
2613
2614         INSIST(ISC_LIST_EMPTY(fctx->forwaddrs));
2615         INSIST(ISC_LIST_EMPTY(fctx->altaddrs));
2616
2617         /*
2618          * If this fctx has forwarders, use them; otherwise use any
2619          * selective forwarders specified in the view; otherwise use the
2620          * resolver's forwarders (if any).
2621          */
2622         sa = ISC_LIST_HEAD(fctx->forwarders);
2623         if (sa == NULL) {
2624                 dns_forwarders_t *forwarders = NULL;
2625                 dns_name_t *name = &fctx->name;
2626                 dns_name_t suffix;
2627                 unsigned int labels;
2628                 dns_fixedname_t fixed;
2629                 dns_name_t *domain;
2630
2631                 /*
2632                  * DS records are found in the parent server.
2633                  * Strip label to get the correct forwarder (if any).
2634                  */
2635                 if (dns_rdatatype_atparent(fctx->type) &&
2636                     dns_name_countlabels(name) > 1) {
2637                         dns_name_init(&suffix, NULL);
2638                         labels = dns_name_countlabels(name);
2639                         dns_name_getlabelsequence(name, 1, labels - 1, &suffix);
2640                         name = &suffix;
2641                 }
2642
2643                 dns_fixedname_init(&fixed);
2644                 domain = dns_fixedname_name(&fixed);
2645                 result = dns_fwdtable_find2(fctx->res->view->fwdtable, name,
2646                                             domain, &forwarders);
2647                 if (result == ISC_R_SUCCESS) {
2648                         sa = ISC_LIST_HEAD(forwarders->addrs);
2649                         fctx->fwdpolicy = forwarders->fwdpolicy;
2650                         if (fctx->fwdpolicy == dns_fwdpolicy_only &&
2651                             isstrictsubdomain(domain, &fctx->domain)) {
2652                                 dns_name_free(&fctx->domain, fctx->mctx);
2653                                 dns_name_init(&fctx->domain, NULL);
2654                                 result = dns_name_dup(domain, fctx->mctx,
2655                                                       &fctx->domain);
2656                                 if (result != ISC_R_SUCCESS)
2657                                         return (result);
2658                         }
2659                 }
2660         }
2661
2662         while (sa != NULL) {
2663                 if ((isc_sockaddr_pf(sa) == AF_INET &&
2664                          fctx->res->dispatches4 == NULL) ||
2665                     (isc_sockaddr_pf(sa) == AF_INET6 &&
2666                         fctx->res->dispatches6 == NULL)) {
2667                                 sa = ISC_LIST_NEXT(sa, link);
2668                                 continue;
2669                 }
2670                 ai = NULL;
2671                 result = dns_adb_findaddrinfo(fctx->adb,
2672                                               sa, &ai, 0);  /* XXXMLG */
2673                 if (result == ISC_R_SUCCESS) {
2674                         dns_adbaddrinfo_t *cur;
2675                         ai->flags |= FCTX_ADDRINFO_FORWARDER;
2676                         cur = ISC_LIST_HEAD(fctx->forwaddrs);
2677                         while (cur != NULL && cur->srtt < ai->srtt)
2678                                 cur = ISC_LIST_NEXT(cur, publink);
2679                         if (cur != NULL)
2680                                 ISC_LIST_INSERTBEFORE(fctx->forwaddrs, cur,
2681                                                       ai, publink);
2682                         else
2683                                 ISC_LIST_APPEND(fctx->forwaddrs, ai, publink);
2684                 }
2685                 sa = ISC_LIST_NEXT(sa, link);
2686         }
2687
2688         /*
2689          * If the forwarding policy is "only", we don't need the addresses
2690          * of the nameservers.
2691          */
2692         if (fctx->fwdpolicy == dns_fwdpolicy_only)
2693                 goto out;
2694
2695         /*
2696          * Normal nameservers.
2697          */
2698
2699         stdoptions = DNS_ADBFIND_WANTEVENT | DNS_ADBFIND_EMPTYEVENT;
2700         if (fctx->restarts == 1) {
2701                 /*
2702                  * To avoid sending out a flood of queries likely to
2703                  * result in NXRRSET, we suppress fetches for address
2704                  * families we don't have the first time through,
2705                  * provided that we have addresses in some family we
2706                  * can use.
2707                  *
2708                  * We don't want to set this option all the time, since
2709                  * if fctx->restarts > 1, we've clearly been having trouble
2710                  * with the addresses we had, so getting more could help.
2711                  */
2712                 stdoptions |= DNS_ADBFIND_AVOIDFETCHES;
2713         }
2714         if (res->dispatches4 != NULL)
2715                 stdoptions |= DNS_ADBFIND_INET;
2716         if (res->dispatches6 != NULL)
2717                 stdoptions |= DNS_ADBFIND_INET6;
2718         isc_stdtime_get(&now);
2719
2720         INSIST(ISC_LIST_EMPTY(fctx->finds));
2721         INSIST(ISC_LIST_EMPTY(fctx->altfinds));
2722
2723         for (result = dns_rdataset_first(&fctx->nameservers);
2724              result == ISC_R_SUCCESS;
2725              result = dns_rdataset_next(&fctx->nameservers))
2726         {
2727                 dns_rdataset_current(&fctx->nameservers, &rdata);
2728                 /*
2729                  * Extract the name from the NS record.
2730                  */
2731                 result = dns_rdata_tostruct(&rdata, &ns, NULL);
2732                 if (result != ISC_R_SUCCESS)
2733                         continue;
2734
2735                 findname(fctx, &ns.name, 0, stdoptions, 0, now,
2736                          &need_alternate);
2737                 dns_rdata_reset(&rdata);
2738                 dns_rdata_freestruct(&ns);
2739         }
2740         if (result != ISC_R_NOMORE)
2741                 return (result);
2742
2743         /*
2744          * Do we need to use 6 to 4?
2745          */
2746         if (need_alternate) {
2747                 int family;
2748                 alternate_t *a;
2749                 family = (res->dispatches6 != NULL) ? AF_INET6 : AF_INET;
2750                 for (a = ISC_LIST_HEAD(fctx->res->alternates);
2751                      a != NULL;
2752                      a = ISC_LIST_NEXT(a, link)) {
2753                         if (!a->isaddress) {
2754                                 findname(fctx, &a->_u._n.name, a->_u._n.port,
2755                                          stdoptions, FCTX_ADDRINFO_FORWARDER,
2756                                          now, NULL);
2757                                 continue;
2758                         }
2759                         if (isc_sockaddr_pf(&a->_u.addr) != family)
2760                                 continue;
2761                         ai = NULL;
2762                         result = dns_adb_findaddrinfo(fctx->adb, &a->_u.addr,
2763                                                       &ai, 0);
2764                         if (result == ISC_R_SUCCESS) {
2765                                 dns_adbaddrinfo_t *cur;
2766                                 ai->flags |= FCTX_ADDRINFO_FORWARDER;
2767                                 cur = ISC_LIST_HEAD(fctx->altaddrs);
2768                                 while (cur != NULL && cur->srtt < ai->srtt)
2769                                         cur = ISC_LIST_NEXT(cur, publink);
2770                                 if (cur != NULL)
2771                                         ISC_LIST_INSERTBEFORE(fctx->altaddrs,
2772                                                               cur, ai, publink);
2773                                 else
2774                                         ISC_LIST_APPEND(fctx->altaddrs, ai,
2775                                                         publink);
2776                         }
2777                 }
2778         }
2779
2780  out:
2781         /*
2782          * Mark all known bad servers.
2783          */
2784         all_bad = mark_bad(fctx);
2785
2786         /*
2787          * How are we doing?
2788          */
2789         if (all_bad) {
2790                 /*
2791                  * We've got no addresses.
2792                  */
2793                 if (fctx->pending > 0) {
2794                         /*
2795                          * We're fetching the addresses, but don't have any
2796                          * yet.   Tell the caller to wait for an answer.
2797                          */
2798                         result = DNS_R_WAIT;
2799                 } else {
2800                         isc_time_t expire;
2801                         isc_interval_t i;
2802                         /*
2803                          * We've lost completely.  We don't know any
2804                          * addresses, and the ADB has told us it can't get
2805                          * them.
2806                          */
2807                         FCTXTRACE("no addresses");
2808                         isc_interval_set(&i, DNS_BADCACHE_TTL(fctx), 0);
2809                         result = isc_time_nowplusinterval(&expire, &i);
2810                         if (badcache &&
2811                             (fctx->type == dns_rdatatype_dnskey ||
2812                              fctx->type == dns_rdatatype_dlv ||
2813                              fctx->type == dns_rdatatype_ds) &&
2814                              result == ISC_R_SUCCESS)
2815                                 dns_resolver_addbadcache(fctx->res,
2816                                                          &fctx->name,
2817                                                          fctx->type, &expire);
2818                         result = ISC_R_FAILURE;
2819                 }
2820         } else {
2821                 /*
2822                  * We've found some addresses.  We might still be looking
2823                  * for more addresses.
2824                  */
2825                 sort_finds(&fctx->finds);
2826                 sort_finds(&fctx->altfinds);
2827                 result = ISC_R_SUCCESS;
2828         }
2829
2830         return (result);
2831 }
2832
2833 static inline void
2834 possibly_mark(fetchctx_t *fctx, dns_adbaddrinfo_t *addr)
2835 {
2836         isc_netaddr_t na;
2837         char buf[ISC_NETADDR_FORMATSIZE];
2838         isc_sockaddr_t *sa;
2839         isc_boolean_t aborted = ISC_FALSE;
2840         isc_boolean_t bogus;
2841         dns_acl_t *blackhole;
2842         isc_netaddr_t ipaddr;
2843         dns_peer_t *peer = NULL;
2844         dns_resolver_t *res;
2845         const char *msg = NULL;
2846
2847         sa = &addr->sockaddr;
2848
2849         res = fctx->res;
2850         isc_netaddr_fromsockaddr(&ipaddr, sa);
2851         blackhole = dns_dispatchmgr_getblackhole(res->dispatchmgr);
2852         (void) dns_peerlist_peerbyaddr(res->view->peers, &ipaddr, &peer);
2853
2854         if (blackhole != NULL) {
2855                 int match;
2856
2857                 if (dns_acl_match(&ipaddr, NULL, blackhole,
2858                                   &res->view->aclenv,
2859                                   &match, NULL) == ISC_R_SUCCESS &&
2860                     match > 0)
2861                         aborted = ISC_TRUE;
2862         }
2863
2864         if (peer != NULL &&
2865             dns_peer_getbogus(peer, &bogus) == ISC_R_SUCCESS &&
2866             bogus)
2867                 aborted = ISC_TRUE;
2868
2869         if (aborted) {
2870                 addr->flags |= FCTX_ADDRINFO_MARK;
2871                 msg = "ignoring blackholed / bogus server: ";
2872         } else if (isc_sockaddr_ismulticast(sa)) {
2873                 addr->flags |= FCTX_ADDRINFO_MARK;
2874                 msg = "ignoring multicast address: ";
2875         } else if (isc_sockaddr_isexperimental(sa)) {
2876                 addr->flags |= FCTX_ADDRINFO_MARK;
2877                 msg = "ignoring experimental address: ";
2878         } else if (sa->type.sa.sa_family != AF_INET6) {
2879                 return;
2880         } else if (IN6_IS_ADDR_V4MAPPED(&sa->type.sin6.sin6_addr)) {
2881                 addr->flags |= FCTX_ADDRINFO_MARK;
2882                 msg = "ignoring IPv6 mapped IPV4 address: ";
2883         } else if (IN6_IS_ADDR_V4COMPAT(&sa->type.sin6.sin6_addr)) {
2884                 addr->flags |= FCTX_ADDRINFO_MARK;
2885                 msg = "ignoring IPv6 compatibility IPV4 address: ";
2886         } else
2887                 return;
2888
2889         if (!isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(3)))
2890                 return;
2891
2892         isc_netaddr_fromsockaddr(&na, sa);
2893         isc_netaddr_format(&na, buf, sizeof(buf));
2894         FCTXTRACE2(msg, buf);
2895 }
2896
2897 static inline dns_adbaddrinfo_t *
2898 fctx_nextaddress(fetchctx_t *fctx) {
2899         dns_adbfind_t *find, *start;
2900         dns_adbaddrinfo_t *addrinfo;
2901         dns_adbaddrinfo_t *faddrinfo;
2902
2903         /*
2904          * Return the next untried address, if any.
2905          */
2906
2907         /*
2908          * Find the first unmarked forwarder (if any).
2909          */
2910         for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
2911              addrinfo != NULL;
2912              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2913                 if (!UNMARKED(addrinfo))
2914                         continue;
2915                 possibly_mark(fctx, addrinfo);
2916                 if (UNMARKED(addrinfo)) {
2917                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2918                         fctx->find = NULL;
2919                         return (addrinfo);
2920                 }
2921         }
2922
2923         /*
2924          * No forwarders.  Move to the next find.
2925          */
2926
2927         fctx->attributes |= FCTX_ATTR_TRIEDFIND;
2928
2929         find = fctx->find;
2930         if (find == NULL)
2931                 find = ISC_LIST_HEAD(fctx->finds);
2932         else {
2933                 find = ISC_LIST_NEXT(find, publink);
2934                 if (find == NULL)
2935                         find = ISC_LIST_HEAD(fctx->finds);
2936         }
2937
2938         /*
2939          * Find the first unmarked addrinfo.
2940          */
2941         addrinfo = NULL;
2942         if (find != NULL) {
2943                 start = find;
2944                 do {
2945                         for (addrinfo = ISC_LIST_HEAD(find->list);
2946                              addrinfo != NULL;
2947                              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2948                                 if (!UNMARKED(addrinfo))
2949                                         continue;
2950                                 possibly_mark(fctx, addrinfo);
2951                                 if (UNMARKED(addrinfo)) {
2952                                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2953                                         break;
2954                                 }
2955                         }
2956                         if (addrinfo != NULL)
2957                                 break;
2958                         find = ISC_LIST_NEXT(find, publink);
2959                         if (find == NULL)
2960                                 find = ISC_LIST_HEAD(fctx->finds);
2961                 } while (find != start);
2962         }
2963
2964         fctx->find = find;
2965         if (addrinfo != NULL)
2966                 return (addrinfo);
2967
2968         /*
2969          * No nameservers left.  Try alternates.
2970          */
2971
2972         fctx->attributes |= FCTX_ATTR_TRIEDALT;
2973
2974         find = fctx->altfind;
2975         if (find == NULL)
2976                 find = ISC_LIST_HEAD(fctx->altfinds);
2977         else {
2978                 find = ISC_LIST_NEXT(find, publink);
2979                 if (find == NULL)
2980                         find = ISC_LIST_HEAD(fctx->altfinds);
2981         }
2982
2983         /*
2984          * Find the first unmarked addrinfo.
2985          */
2986         addrinfo = NULL;
2987         if (find != NULL) {
2988                 start = find;
2989                 do {
2990                         for (addrinfo = ISC_LIST_HEAD(find->list);
2991                              addrinfo != NULL;
2992                              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2993                                 if (!UNMARKED(addrinfo))
2994                                         continue;
2995                                 possibly_mark(fctx, addrinfo);
2996                                 if (UNMARKED(addrinfo)) {
2997                                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2998                                         break;
2999                                 }
3000                         }
3001                         if (addrinfo != NULL)
3002                                 break;
3003                         find = ISC_LIST_NEXT(find, publink);
3004                         if (find == NULL)
3005                                 find = ISC_LIST_HEAD(fctx->altfinds);
3006                 } while (find != start);
3007         }
3008
3009         faddrinfo = addrinfo;
3010
3011         /*
3012          * See if we have a better alternate server by address.
3013          */
3014
3015         for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs);
3016              addrinfo != NULL;
3017              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
3018                 if (!UNMARKED(addrinfo))
3019                         continue;
3020                 possibly_mark(fctx, addrinfo);
3021                 if (UNMARKED(addrinfo) &&
3022                     (faddrinfo == NULL ||
3023                      addrinfo->srtt < faddrinfo->srtt)) {
3024                         if (faddrinfo != NULL)
3025                                 faddrinfo->flags &= ~FCTX_ADDRINFO_MARK;
3026                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
3027                         break;
3028                 }
3029         }
3030
3031         if (addrinfo == NULL) {
3032                 addrinfo = faddrinfo;
3033                 fctx->altfind = find;
3034         }
3035
3036         return (addrinfo);
3037 }
3038
3039 static void
3040 fctx_try(fetchctx_t *fctx, isc_boolean_t retrying, isc_boolean_t badcache) {
3041         isc_result_t result;
3042         dns_adbaddrinfo_t *addrinfo;
3043
3044         FCTXTRACE("try");
3045
3046         REQUIRE(!ADDRWAIT(fctx));
3047
3048         if (fctx->totalqueries > DEFAULT_MAX_QUERIES)
3049                 fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
3050
3051         addrinfo = fctx_nextaddress(fctx);
3052         if (addrinfo == NULL) {
3053                 /*
3054                  * We have no more addresses.  Start over.
3055                  */
3056                 fctx_cancelqueries(fctx, ISC_TRUE);
3057                 fctx_cleanupfinds(fctx);
3058                 fctx_cleanupaltfinds(fctx);
3059                 fctx_cleanupforwaddrs(fctx);
3060                 fctx_cleanupaltaddrs(fctx);
3061                 result = fctx_getaddresses(fctx, badcache);
3062                 if (result == DNS_R_WAIT) {
3063                         /*
3064                          * Sleep waiting for addresses.
3065                          */
3066                         FCTXTRACE("addrwait");
3067                         fctx->attributes |= FCTX_ATTR_ADDRWAIT;
3068                         return;
3069                 } else if (result != ISC_R_SUCCESS) {
3070                         /*
3071                          * Something bad happened.
3072                          */
3073                         fctx_done(fctx, result, __LINE__);
3074                         return;
3075                 }
3076
3077                 addrinfo = fctx_nextaddress(fctx);
3078                 /*
3079                  * While we may have addresses from the ADB, they
3080                  * might be bad ones.  In this case, return SERVFAIL.
3081                  */
3082                 if (addrinfo == NULL) {
3083                         fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
3084                         return;
3085                 }
3086         }
3087
3088         result = fctx_query(fctx, addrinfo, fctx->options);
3089         if (result != ISC_R_SUCCESS)
3090                 fctx_done(fctx, result, __LINE__);
3091         else if (retrying)
3092                 inc_stats(fctx->res, dns_resstatscounter_retry);
3093 }
3094
3095 static isc_boolean_t
3096 fctx_unlink(fetchctx_t *fctx) {
3097         dns_resolver_t *res;
3098         unsigned int bucketnum;
3099
3100         /*
3101          * Caller must be holding the bucket lock.
3102          */
3103
3104         REQUIRE(VALID_FCTX(fctx));
3105         REQUIRE(fctx->state == fetchstate_done ||
3106                 fctx->state == fetchstate_init);
3107         REQUIRE(ISC_LIST_EMPTY(fctx->events));
3108         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
3109         REQUIRE(ISC_LIST_EMPTY(fctx->finds));
3110         REQUIRE(ISC_LIST_EMPTY(fctx->altfinds));
3111         REQUIRE(fctx->pending == 0);
3112         REQUIRE(fctx->references == 0);
3113         REQUIRE(ISC_LIST_EMPTY(fctx->validators));
3114
3115         FCTXTRACE("unlink");
3116
3117         res = fctx->res;
3118         bucketnum = fctx->bucketnum;
3119
3120         ISC_LIST_UNLINK(res->buckets[bucketnum].fctxs, fctx, link);
3121
3122         LOCK(&res->nlock);
3123         res->nfctx--;
3124         UNLOCK(&res->nlock);
3125
3126         if (res->buckets[bucketnum].exiting &&
3127             ISC_LIST_EMPTY(res->buckets[bucketnum].fctxs))
3128                 return (ISC_TRUE);
3129
3130         return (ISC_FALSE);
3131 }
3132
3133 static void
3134 fctx_destroy(fetchctx_t *fctx) {
3135         isc_sockaddr_t *sa, *next_sa;
3136
3137         REQUIRE(VALID_FCTX(fctx));
3138         REQUIRE(fctx->state == fetchstate_done ||
3139                 fctx->state == fetchstate_init);
3140         REQUIRE(ISC_LIST_EMPTY(fctx->events));
3141         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
3142         REQUIRE(ISC_LIST_EMPTY(fctx->finds));
3143         REQUIRE(ISC_LIST_EMPTY(fctx->altfinds));
3144         REQUIRE(fctx->pending == 0);
3145         REQUIRE(fctx->references == 0);
3146         REQUIRE(ISC_LIST_EMPTY(fctx->validators));
3147         REQUIRE(!ISC_LINK_LINKED(fctx, link));
3148
3149         FCTXTRACE("destroy");
3150
3151         /*
3152          * Free bad.
3153          */
3154         for (sa = ISC_LIST_HEAD(fctx->bad);
3155              sa != NULL;
3156              sa = next_sa) {
3157                 next_sa = ISC_LIST_NEXT(sa, link);
3158                 ISC_LIST_UNLINK(fctx->bad, sa, link);
3159                 isc_mem_put(fctx->mctx, sa, sizeof(*sa));
3160         }
3161
3162         for (sa = ISC_LIST_HEAD(fctx->edns);
3163              sa != NULL;
3164              sa = next_sa) {
3165                 next_sa = ISC_LIST_NEXT(sa, link);
3166                 ISC_LIST_UNLINK(fctx->edns, sa, link);
3167                 isc_mem_put(fctx->mctx, sa, sizeof(*sa));
3168         }
3169
3170         for (sa = ISC_LIST_HEAD(fctx->edns512);
3171              sa != NULL;
3172              sa = next_sa) {
3173                 next_sa = ISC_LIST_NEXT(sa, link);
3174                 ISC_LIST_UNLINK(fctx->edns512, sa, link);
3175                 isc_mem_put(fctx->mctx, sa, sizeof(*sa));
3176         }
3177
3178         for (sa = ISC_LIST_HEAD(fctx->bad_edns);
3179              sa != NULL;
3180              sa = next_sa) {
3181                 next_sa = ISC_LIST_NEXT(sa, link);
3182                 ISC_LIST_UNLINK(fctx->bad_edns, sa, link);
3183                 isc_mem_put(fctx->mctx, sa, sizeof(*sa));
3184         }
3185
3186         isc_timer_detach(&fctx->timer);
3187         dns_message_destroy(&fctx->rmessage);
3188         dns_message_destroy(&fctx->qmessage);
3189         if (dns_name_countlabels(&fctx->domain) > 0)
3190                 dns_name_free(&fctx->domain, fctx->mctx);
3191         if (dns_rdataset_isassociated(&fctx->nameservers))
3192                 dns_rdataset_disassociate(&fctx->nameservers);
3193         dns_name_free(&fctx->name, fctx->mctx);
3194         dns_db_detach(&fctx->cache);
3195         dns_adb_detach(&fctx->adb);
3196         isc_mem_free(fctx->mctx, fctx->info);
3197         isc_mem_putanddetach(&fctx->mctx, fctx, sizeof(*fctx));
3198 }
3199
3200 /*
3201  * Fetch event handlers.
3202  */
3203
3204 static void
3205 fctx_timeout(isc_task_t *task, isc_event_t *event) {
3206         fetchctx_t *fctx = event->ev_arg;
3207         isc_timerevent_t *tevent = (isc_timerevent_t *)event;
3208         resquery_t *query;
3209
3210         REQUIRE(VALID_FCTX(fctx));
3211
3212         UNUSED(task);
3213
3214         FCTXTRACE("timeout");
3215
3216         inc_stats(fctx->res, dns_resstatscounter_querytimeout);
3217
3218         if (event->ev_type == ISC_TIMEREVENT_LIFE) {
3219                 fctx->reason = NULL;
3220                 fctx_done(fctx, ISC_R_TIMEDOUT, __LINE__);
3221         } else {
3222                 isc_result_t result;
3223
3224                 fctx->timeouts++;
3225                 fctx->timeout = ISC_TRUE;
3226                 /*
3227                  * We could cancel the running queries here, or we could let
3228                  * them keep going.  Since we normally use separate sockets for
3229                  * different queries, we adopt the former approach to reduce
3230                  * the number of open sockets: cancel the oldest query if it
3231                  * expired after the query had started (this is usually the
3232                  * case but is not always so, depending on the task schedule
3233                  * timing).
3234                  */
3235                 query = ISC_LIST_HEAD(fctx->queries);
3236                 if (query != NULL &&
3237                     isc_time_compare(&tevent->due, &query->start) >= 0) {
3238                         fctx_cancelquery(&query, NULL, NULL, ISC_TRUE);
3239                 }
3240                 fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
3241                 /*
3242                  * Our timer has triggered.  Reestablish the fctx lifetime
3243                  * timer.
3244                  */
3245                 result = fctx_starttimer(fctx);
3246                 if (result != ISC_R_SUCCESS)
3247                         fctx_done(fctx, result, __LINE__);
3248                 else
3249                         /*
3250                          * Keep trying.
3251                          */
3252                         fctx_try(fctx, ISC_TRUE, ISC_FALSE);
3253         }
3254
3255         isc_event_free(&event);
3256 }
3257
3258 static void
3259 fctx_shutdown(fetchctx_t *fctx) {
3260         isc_event_t *cevent;
3261
3262         /*
3263          * Start the shutdown process for fctx, if it isn't already underway.
3264          */
3265
3266         FCTXTRACE("shutdown");
3267
3268         /*
3269          * The caller must be holding the appropriate bucket lock.
3270          */
3271
3272         if (fctx->want_shutdown)
3273                 return;
3274
3275         fctx->want_shutdown = ISC_TRUE;
3276
3277         /*
3278          * Unless we're still initializing (in which case the
3279          * control event is still outstanding), we need to post
3280          * the control event to tell the fetch we want it to
3281          * exit.
3282          */
3283         if (fctx->state != fetchstate_init) {
3284                 cevent = &fctx->control_event;
3285                 isc_task_send(fctx->res->buckets[fctx->bucketnum].task,
3286                               &cevent);
3287         }
3288 }
3289
3290 static void
3291 fctx_doshutdown(isc_task_t *task, isc_event_t *event) {
3292         fetchctx_t *fctx = event->ev_arg;
3293         isc_boolean_t bucket_empty = ISC_FALSE;
3294         dns_resolver_t *res;
3295         unsigned int bucketnum;
3296         dns_validator_t *validator;
3297         isc_boolean_t destroy = ISC_FALSE;
3298
3299         REQUIRE(VALID_FCTX(fctx));
3300
3301         UNUSED(task);
3302
3303         res = fctx->res;
3304         bucketnum = fctx->bucketnum;
3305
3306         FCTXTRACE("doshutdown");
3307
3308         /*
3309          * An fctx that is shutting down is no longer in ADDRWAIT mode.
3310          */
3311         fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
3312
3313         /*
3314          * Cancel all pending validators.  Note that this must be done
3315          * without the bucket lock held, since that could cause deadlock.
3316          */
3317         validator = ISC_LIST_HEAD(fctx->validators);
3318         while (validator != NULL) {
3319                 dns_validator_cancel(validator);
3320                 validator = ISC_LIST_NEXT(validator, link);
3321         }
3322
3323         if (fctx->nsfetch != NULL)
3324                 dns_resolver_cancelfetch(fctx->nsfetch);
3325
3326         /*
3327          * Shut down anything that is still running on behalf of this
3328          * fetch.  To avoid deadlock with the ADB, we must do this
3329          * before we lock the bucket lock.
3330          */
3331         fctx_stopeverything(fctx, ISC_FALSE);
3332
3333         LOCK(&res->buckets[bucketnum].lock);
3334
3335         fctx->attributes |= FCTX_ATTR_SHUTTINGDOWN;
3336
3337         INSIST(fctx->state == fetchstate_active ||
3338                fctx->state == fetchstate_done);
3339         INSIST(fctx->want_shutdown);
3340
3341         if (fctx->state != fetchstate_done) {
3342                 fctx->state = fetchstate_done;
3343                 fctx_sendevents(fctx, ISC_R_CANCELED, __LINE__);
3344         }
3345
3346         if (fctx->references == 0 && fctx->pending == 0 &&
3347             fctx->nqueries == 0 && ISC_LIST_EMPTY(fctx->validators)) {
3348                 bucket_empty = fctx_unlink(fctx);
3349                 destroy = ISC_TRUE;
3350         }
3351
3352         UNLOCK(&res->buckets[bucketnum].lock);
3353
3354         if (destroy) {
3355                 fctx_destroy(fctx);
3356                 if (bucket_empty)
3357                         empty_bucket(res);
3358         }
3359 }
3360
3361 static void
3362 fctx_start(isc_task_t *task, isc_event_t *event) {
3363         fetchctx_t *fctx = event->ev_arg;
3364         isc_boolean_t done = ISC_FALSE, bucket_empty = ISC_FALSE;
3365         dns_resolver_t *res;
3366         unsigned int bucketnum;
3367         isc_boolean_t destroy = ISC_FALSE;
3368
3369         REQUIRE(VALID_FCTX(fctx));
3370
3371         UNUSED(task);
3372
3373         res = fctx->res;
3374         bucketnum = fctx->bucketnum;
3375
3376         FCTXTRACE("start");
3377
3378         LOCK(&res->buckets[bucketnum].lock);
3379
3380         INSIST(fctx->state == fetchstate_init);
3381         if (fctx->want_shutdown) {
3382                 /*
3383                  * We haven't started this fctx yet, and we've been requested
3384                  * to shut it down.
3385                  */
3386                 fctx->attributes |= FCTX_ATTR_SHUTTINGDOWN;
3387                 fctx->state = fetchstate_done;
3388                 fctx_sendevents(fctx, ISC_R_CANCELED, __LINE__);
3389                 /*
3390                  * Since we haven't started, we INSIST that we have no
3391                  * pending ADB finds and no pending validations.
3392                  */
3393                 INSIST(fctx->pending == 0);
3394                 INSIST(fctx->nqueries == 0);
3395                 INSIST(ISC_LIST_EMPTY(fctx->validators));
3396                 if (fctx->references == 0) {
3397                         /*
3398                          * It's now safe to destroy this fctx.
3399                          */
3400                         bucket_empty = fctx_unlink(fctx);
3401                         destroy = ISC_TRUE;
3402                 }
3403                 done = ISC_TRUE;
3404         } else {
3405                 /*
3406                  * Normal fctx startup.
3407                  */
3408                 fctx->state = fetchstate_active;
3409                 fctx->totalqueries = 0;
3410                 /*
3411                  * Reset the control event for later use in shutting down
3412                  * the fctx.
3413                  */
3414                 ISC_EVENT_INIT(event, sizeof(*event), 0, NULL,
3415                                DNS_EVENT_FETCHCONTROL, fctx_doshutdown, fctx,
3416                                NULL, NULL, NULL);
3417         }
3418
3419         UNLOCK(&res->buckets[bucketnum].lock);
3420
3421         if (!done) {
3422                 isc_result_t result;
3423
3424                 INSIST(!destroy);
3425
3426                 /*
3427                  * All is well.  Start working on the fetch.
3428                  */
3429                 result = fctx_starttimer(fctx);
3430                 if (result != ISC_R_SUCCESS)
3431                         fctx_done(fctx, result, __LINE__);
3432                 else
3433                         fctx_try(fctx, ISC_FALSE, ISC_FALSE);
3434         } else if (destroy) {
3435                         fctx_destroy(fctx);
3436                 if (bucket_empty)
3437                         empty_bucket(res);
3438         }
3439 }
3440
3441 /*
3442  * Fetch Creation, Joining, and Cancelation.
3443  */
3444
3445 static inline isc_result_t
3446 fctx_join(fetchctx_t *fctx, isc_task_t *task, isc_sockaddr_t *client,
3447           dns_messageid_t id, isc_taskaction_t action, void *arg,
3448           dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
3449           dns_fetch_t *fetch)
3450 {
3451         isc_task_t *clone;
3452         dns_fetchevent_t *event;
3453
3454         FCTXTRACE("join");
3455
3456         /*
3457          * We store the task we're going to send this event to in the
3458          * sender field.  We'll make the fetch the sender when we actually
3459          * send the event.
3460          */
3461         clone = NULL;
3462         isc_task_attach(task, &clone);
3463         event = (dns_fetchevent_t *)
3464                 isc_event_allocate(fctx->res->mctx, clone, DNS_EVENT_FETCHDONE,
3465                                    action, arg, sizeof(*event));
3466         if (event == NULL) {
3467                 isc_task_detach(&clone);
3468                 return (ISC_R_NOMEMORY);
3469         }
3470         event->result = DNS_R_SERVFAIL;
3471         event->qtype = fctx->type;
3472         event->db = NULL;
3473         event->node = NULL;
3474         event->rdataset = rdataset;
3475         event->sigrdataset = sigrdataset;
3476         event->fetch = fetch;
3477         event->client = client;
3478         event->id = id;
3479         event->qtotal = 0;
3480         dns_fixedname_init(&event->foundname);
3481
3482         /*
3483          * Make sure that we can store the sigrdataset in the
3484          * first event if it is needed by any of the events.
3485          */
3486         if (event->sigrdataset != NULL)
3487                 ISC_LIST_PREPEND(fctx->events, event, ev_link);
3488         else
3489                 ISC_LIST_APPEND(fctx->events, event, ev_link);
3490         fctx->references++;
3491         fctx->client = client;
3492
3493         fetch->magic = DNS_FETCH_MAGIC;
3494         fetch->private = fctx;
3495
3496         return (ISC_R_SUCCESS);
3497 }
3498
3499 static inline void
3500 log_ns_ttl(fetchctx_t *fctx, const char *where) {
3501         char namebuf[DNS_NAME_FORMATSIZE];
3502         char domainbuf[DNS_NAME_FORMATSIZE];
3503
3504         dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
3505         dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
3506         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
3507                       DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(10),
3508                       "log_ns_ttl: fctx %p: %s: %s (in '%s'?): %u %u",
3509                       fctx, where, namebuf, domainbuf,
3510                       fctx->ns_ttl_ok, fctx->ns_ttl);
3511 }
3512
3513 static isc_result_t
3514 fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type,
3515             dns_name_t *domain, dns_rdataset_t *nameservers,
3516             unsigned int options, unsigned int bucketnum, unsigned int depth,
3517             fetchctx_t **fctxp)
3518 {
3519         fetchctx_t *fctx;
3520         isc_result_t result;
3521         isc_result_t iresult;
3522         isc_interval_t interval;
3523         dns_fixedname_t fixed;
3524         unsigned int findoptions = 0;
3525         char buf[DNS_NAME_FORMATSIZE + DNS_RDATATYPE_FORMATSIZE];
3526         char typebuf[DNS_RDATATYPE_FORMATSIZE];
3527         dns_name_t suffix;
3528         isc_mem_t *mctx;
3529
3530         /*
3531          * Caller must be holding the lock for bucket number 'bucketnum'.
3532          */
3533         REQUIRE(fctxp != NULL && *fctxp == NULL);
3534
3535         mctx = res->buckets[bucketnum].mctx;
3536         fctx = isc_mem_get(mctx, sizeof(*fctx));
3537         if (fctx == NULL)
3538                 return (ISC_R_NOMEMORY);
3539         dns_name_format(name, buf, sizeof(buf));
3540         dns_rdatatype_format(type, typebuf, sizeof(typebuf));
3541         strcat(buf, "/");       /* checked */
3542         strcat(buf, typebuf);   /* checked */
3543         fctx->info = isc_mem_strdup(mctx, buf);
3544         if (fctx->info == NULL) {
3545                 result = ISC_R_NOMEMORY;
3546                 goto cleanup_fetch;
3547         }
3548         FCTXTRACE("create");
3549         dns_name_init(&fctx->name, NULL);
3550         result = dns_name_dup(name, mctx, &fctx->name);
3551         if (result != ISC_R_SUCCESS)
3552                 goto cleanup_info;
3553         dns_name_init(&fctx->domain, NULL);
3554         dns_rdataset_init(&fctx->nameservers);
3555
3556         fctx->type = type;
3557         fctx->options = options;
3558         /*
3559          * Note!  We do not attach to the task.  We are relying on the
3560          * resolver to ensure that this task doesn't go away while we are
3561          * using it.
3562          */
3563         fctx->res = res;
3564         fctx->references = 0;
3565         fctx->bucketnum = bucketnum;
3566         fctx->state = fetchstate_init;
3567         fctx->want_shutdown = ISC_FALSE;
3568         fctx->cloned = ISC_FALSE;
3569         fctx->depth = depth;
3570         ISC_LIST_INIT(fctx->queries);
3571         ISC_LIST_INIT(fctx->finds);
3572         ISC_LIST_INIT(fctx->altfinds);
3573         ISC_LIST_INIT(fctx->forwaddrs);
3574         ISC_LIST_INIT(fctx->altaddrs);
3575         ISC_LIST_INIT(fctx->forwarders);
3576         fctx->fwdpolicy = dns_fwdpolicy_none;
3577         ISC_LIST_INIT(fctx->bad);
3578         ISC_LIST_INIT(fctx->edns);
3579         ISC_LIST_INIT(fctx->edns512);
3580         ISC_LIST_INIT(fctx->bad_edns);
3581         ISC_LIST_INIT(fctx->validators);
3582         fctx->validator = NULL;
3583         fctx->find = NULL;
3584         fctx->altfind = NULL;
3585         fctx->pending = 0;
3586         fctx->restarts = 0;
3587         fctx->querysent = 0;
3588         fctx->totalqueries = 0;
3589         fctx->referrals = 0;
3590         TIME_NOW(&fctx->start);
3591         fctx->timeouts = 0;
3592         fctx->lamecount = 0;
3593         fctx->adberr = 0;
3594         fctx->neterr = 0;
3595         fctx->badresp = 0;
3596         fctx->findfail = 0;
3597         fctx->valfail = 0;
3598         fctx->result = ISC_R_FAILURE;
3599         fctx->vresult = ISC_R_SUCCESS;
3600         fctx->exitline = -1;    /* sentinel */
3601         fctx->logged = ISC_FALSE;
3602         fctx->attributes = 0;
3603         fctx->spilled = ISC_FALSE;
3604         fctx->nqueries = 0;
3605         fctx->reason = NULL;
3606         fctx->rand_buf = 0;
3607         fctx->rand_bits = 0;
3608         fctx->timeout = ISC_FALSE;
3609         fctx->addrinfo = NULL;
3610         fctx->client = NULL;
3611         fctx->ns_ttl = 0;
3612         fctx->ns_ttl_ok = ISC_FALSE;
3613
3614         dns_name_init(&fctx->nsname, NULL);
3615         fctx->nsfetch = NULL;
3616         dns_rdataset_init(&fctx->nsrrset);
3617
3618         if (domain == NULL) {
3619                 dns_forwarders_t *forwarders = NULL;
3620                 unsigned int labels;
3621                 dns_name_t *fwdname = name;
3622
3623                 /*
3624                  * DS records are found in the parent server.
3625                  * Strip label to get the correct forwarder (if any).
3626                  */
3627                 if (dns_rdatatype_atparent(fctx->type) &&
3628                     dns_name_countlabels(name) > 1) {
3629                         dns_name_init(&suffix, NULL);
3630                         labels = dns_name_countlabels(name);
3631                         dns_name_getlabelsequence(name, 1, labels - 1, &suffix);
3632                         fwdname = &suffix;
3633                 }
3634                 dns_fixedname_init(&fixed);
3635                 domain = dns_fixedname_name(&fixed);
3636                 result = dns_fwdtable_find2(fctx->res->view->fwdtable, fwdname,
3637                                             domain, &forwarders);
3638                 if (result == ISC_R_SUCCESS)
3639                         fctx->fwdpolicy = forwarders->fwdpolicy;
3640
3641                 if (fctx->fwdpolicy != dns_fwdpolicy_only) {
3642                         /*
3643                          * The caller didn't supply a query domain and
3644                          * nameservers, and we're not in forward-only mode,
3645                          * so find the best nameservers to use.
3646                          */
3647                         if (dns_rdatatype_atparent(fctx->type))
3648                                 findoptions |= DNS_DBFIND_NOEXACT;
3649                         result = dns_view_findzonecut(res->view, fwdname,
3650                                                       domain, 0, findoptions,
3651                                                       ISC_TRUE,
3652                                                       &fctx->nameservers,
3653                                                       NULL);
3654                         if (result != ISC_R_SUCCESS)
3655                                 goto cleanup_name;
3656
3657                         result = dns_name_dup(domain, mctx, &fctx->domain);
3658                         if (result != ISC_R_SUCCESS) {
3659                                 dns_rdataset_disassociate(&fctx->nameservers);
3660                                 goto cleanup_name;
3661                         }
3662                         fctx->ns_ttl = fctx->nameservers.ttl;
3663                         fctx->ns_ttl_ok = ISC_TRUE;
3664                 } else {
3665                         /*
3666                          * We're in forward-only mode.  Set the query domain.
3667                          */
3668                         result = dns_name_dup(domain, mctx, &fctx->domain);
3669                         if (result != ISC_R_SUCCESS)
3670                                 goto cleanup_name;
3671                 }
3672         } else {
3673                 result = dns_name_dup(domain, mctx, &fctx->domain);
3674                 if (result != ISC_R_SUCCESS)
3675                         goto cleanup_name;
3676                 dns_rdataset_clone(nameservers, &fctx->nameservers);
3677                 fctx->ns_ttl = fctx->nameservers.ttl;
3678                 fctx->ns_ttl_ok = ISC_TRUE;
3679         }
3680
3681         log_ns_ttl(fctx, "fctx_create");
3682
3683         INSIST(dns_name_issubdomain(&fctx->name, &fctx->domain));
3684
3685         fctx->qmessage = NULL;
3686         result = dns_message_create(mctx, DNS_MESSAGE_INTENTRENDER,
3687                                     &fctx->qmessage);
3688
3689         if (result != ISC_R_SUCCESS)
3690                 goto cleanup_domain;
3691
3692         fctx->rmessage = NULL;
3693         result = dns_message_create(mctx, DNS_MESSAGE_INTENTPARSE,
3694                                     &fctx->rmessage);
3695
3696         if (result != ISC_R_SUCCESS)
3697                 goto cleanup_qmessage;
3698
3699         /*
3700          * Compute an expiration time for the entire fetch.
3701          */
3702         isc_interval_set(&interval, res->query_timeout, 0);
3703         iresult = isc_time_nowplusinterval(&fctx->expires, &interval);
3704         if (iresult != ISC_R_SUCCESS) {
3705                 UNEXPECTED_ERROR(__FILE__, __LINE__,
3706                                  "isc_time_nowplusinterval: %s",
3707                                  isc_result_totext(iresult));
3708                 result = ISC_R_UNEXPECTED;
3709                 goto cleanup_rmessage;
3710         }
3711
3712         /*
3713          * Default retry interval initialization.  We set the interval now
3714          * mostly so it won't be uninitialized.  It will be set to the
3715          * correct value before a query is issued.
3716          */
3717         isc_interval_set(&fctx->interval, 2, 0);
3718
3719         /*
3720          * Create an inactive timer.  It will be made active when the fetch
3721          * is actually started.
3722          */
3723         fctx->timer = NULL;
3724         iresult = isc_timer_create(res->timermgr, isc_timertype_inactive,
3725                                    NULL, NULL,
3726                                    res->buckets[bucketnum].task, fctx_timeout,
3727                                    fctx, &fctx->timer);
3728         if (iresult != ISC_R_SUCCESS) {
3729                 UNEXPECTED_ERROR(__FILE__, __LINE__,
3730                                  "isc_timer_create: %s",
3731                                  isc_result_totext(iresult));
3732                 result = ISC_R_UNEXPECTED;
3733                 goto cleanup_rmessage;
3734         }
3735
3736         /*
3737          * Attach to the view's cache and adb.
3738          */
3739         fctx->cache = NULL;
3740         dns_db_attach(res->view->cachedb, &fctx->cache);
3741         fctx->adb = NULL;
3742         dns_adb_attach(res->view->adb, &fctx->adb);
3743         fctx->mctx = NULL;
3744         isc_mem_attach(mctx, &fctx->mctx);
3745
3746         ISC_LIST_INIT(fctx->events);
3747         ISC_LINK_INIT(fctx, link);
3748         fctx->magic = FCTX_MAGIC;
3749
3750         ISC_LIST_APPEND(res->buckets[bucketnum].fctxs, fctx, link);
3751
3752         LOCK(&res->nlock);
3753         res->nfctx++;
3754         UNLOCK(&res->nlock);
3755
3756         *fctxp = fctx;
3757
3758         return (ISC_R_SUCCESS);
3759
3760  cleanup_rmessage:
3761         dns_message_destroy(&fctx->rmessage);
3762
3763  cleanup_qmessage:
3764         dns_message_destroy(&fctx->qmessage);
3765
3766  cleanup_domain:
3767         if (dns_name_countlabels(&fctx->domain) > 0)
3768                 dns_name_free(&fctx->domain, mctx);
3769         if (dns_rdataset_isassociated(&fctx->nameservers))
3770                 dns_rdataset_disassociate(&fctx->nameservers);
3771
3772  cleanup_name:
3773         dns_name_free(&fctx->name, mctx);
3774
3775  cleanup_info:
3776         isc_mem_free(mctx, fctx->info);
3777
3778  cleanup_fetch:
3779         isc_mem_put(mctx, fctx, sizeof(*fctx));
3780
3781         return (result);
3782 }
3783
3784 /*
3785  * Handle Responses
3786  */
3787 static inline isc_boolean_t
3788 is_lame(fetchctx_t *fctx) {
3789         dns_message_t *message = fctx->rmessage;
3790         dns_name_t *name;
3791         dns_rdataset_t *rdataset;
3792         isc_result_t result;
3793
3794         if (message->rcode != dns_rcode_noerror &&
3795             message->rcode != dns_rcode_nxdomain)
3796                 return (ISC_FALSE);
3797
3798         if (message->counts[DNS_SECTION_ANSWER] != 0)
3799                 return (ISC_FALSE);
3800
3801         if (message->counts[DNS_SECTION_AUTHORITY] == 0)
3802                 return (ISC_FALSE);
3803
3804         result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
3805         while (result == ISC_R_SUCCESS) {
3806                 name = NULL;
3807                 dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
3808                 for (rdataset = ISC_LIST_HEAD(name->list);
3809                      rdataset != NULL;
3810                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
3811                         dns_namereln_t namereln;
3812                         int order;
3813                         unsigned int labels;
3814                         if (rdataset->type != dns_rdatatype_ns)
3815                                 continue;
3816                         namereln = dns_name_fullcompare(name, &fctx->domain,
3817                                                         &order, &labels);
3818                         if (namereln == dns_namereln_equal &&
3819                             (message->flags & DNS_MESSAGEFLAG_AA) != 0)
3820                                 return (ISC_FALSE);
3821                         if (namereln == dns_namereln_subdomain)
3822                                 return (ISC_FALSE);
3823                         return (ISC_TRUE);
3824                 }
3825                 result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
3826         }
3827
3828         return (ISC_FALSE);
3829 }
3830
3831 static inline void
3832 log_lame(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo) {
3833         char namebuf[DNS_NAME_FORMATSIZE];
3834         char domainbuf[DNS_NAME_FORMATSIZE];
3835         char addrbuf[ISC_SOCKADDR_FORMATSIZE];
3836
3837         dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
3838         dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
3839         isc_sockaddr_format(&addrinfo->sockaddr, addrbuf, sizeof(addrbuf));
3840         isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS,
3841                       DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
3842                       "lame server resolving '%s' (in '%s'?): %s",
3843                       namebuf, domainbuf, addrbuf);
3844 }
3845
3846 static inline void
3847 log_formerr(fetchctx_t *fctx, const char *format, ...) {
3848         char nsbuf[ISC_SOCKADDR_FORMATSIZE];
3849         char clbuf[ISC_SOCKADDR_FORMATSIZE];
3850         const char *clmsg = "";
3851         char msgbuf[2048];
3852         va_list args;
3853
3854         va_start(args, format);
3855         vsnprintf(msgbuf, sizeof(msgbuf), format, args);
3856         va_end(args);
3857
3858         isc_sockaddr_format(&fctx->addrinfo->sockaddr, nsbuf, sizeof(nsbuf));
3859
3860         if (fctx->client != NULL) {
3861                 clmsg = " for client ";
3862                 isc_sockaddr_format(fctx->client, clbuf, sizeof(clbuf));
3863         } else {
3864                 clbuf[0] = '\0';
3865         }
3866
3867         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
3868                       DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
3869                       "DNS format error from %s resolving %s%s%s: %s",
3870                       nsbuf, fctx->info, clmsg, clbuf, msgbuf);
3871 }
3872
3873 static inline isc_result_t
3874 same_question(fetchctx_t *fctx) {
3875         isc_result_t result;
3876         dns_message_t *message = fctx->rmessage;
3877         dns_name_t *name;
3878         dns_rdataset_t *rdataset;
3879
3880         /*
3881          * Caller must be holding the fctx lock.
3882          */
3883
3884         /*
3885          * XXXRTH  Currently we support only one question.
3886          */
3887         if (message->counts[DNS_SECTION_QUESTION] != 1) {
3888                 log_formerr(fctx, "too many questions");
3889                 return (DNS_R_FORMERR);
3890         }
3891
3892         result = dns_message_firstname(message, DNS_SECTION_QUESTION);
3893         if (result != ISC_R_SUCCESS)
3894                 return (result);
3895         name = NULL;
3896         dns_message_currentname(message, DNS_SECTION_QUESTION, &name);
3897         rdataset = ISC_LIST_HEAD(name->list);
3898         INSIST(rdataset != NULL);
3899         INSIST(ISC_LIST_NEXT(rdataset, link) == NULL);
3900
3901         if (fctx->type != rdataset->type ||
3902             fctx->res->rdclass != rdataset->rdclass ||
3903             !dns_name_equal(&fctx->name, name)) {
3904                 char namebuf[DNS_NAME_FORMATSIZE];
3905                 char class[DNS_RDATACLASS_FORMATSIZE];
3906                 char type[DNS_RDATATYPE_FORMATSIZE];
3907
3908                 dns_name_format(name, namebuf, sizeof(namebuf));
3909                 dns_rdataclass_format(rdataset->rdclass, class, sizeof(class));
3910                 dns_rdatatype_format(rdataset->type, type, sizeof(type));
3911                 log_formerr(fctx, "question section mismatch: got %s/%s/%s",
3912                             namebuf, class, type);
3913                 return (DNS_R_FORMERR);
3914         }
3915
3916         return (ISC_R_SUCCESS);
3917 }
3918
3919 static void
3920 clone_results(fetchctx_t *fctx) {
3921         dns_fetchevent_t *event, *hevent;
3922         isc_result_t result;
3923         dns_name_t *name, *hname;
3924
3925         FCTXTRACE("clone_results");
3926
3927         /*
3928          * Set up any other events to have the same data as the first
3929          * event.
3930          *
3931          * Caller must be holding the appropriate lock.
3932          */
3933
3934         fctx->cloned = ISC_TRUE;
3935         hevent = ISC_LIST_HEAD(fctx->events);
3936         if (hevent == NULL)
3937                 return;
3938         hname = dns_fixedname_name(&hevent->foundname);
3939         for (event = ISC_LIST_NEXT(hevent, ev_link);
3940              event != NULL;
3941              event = ISC_LIST_NEXT(event, ev_link)) {
3942                 name = dns_fixedname_name(&event->foundname);
3943                 result = dns_name_copy(hname, name, NULL);
3944                 if (result != ISC_R_SUCCESS)
3945                         event->result = result;
3946                 else
3947                         event->result = hevent->result;
3948                 dns_db_attach(hevent->db, &event->db);
3949                 dns_db_attachnode(hevent->db, hevent->node, &event->node);
3950                 INSIST(hevent->rdataset != NULL);
3951                 INSIST(event->rdataset != NULL);
3952                 if (dns_rdataset_isassociated(hevent->rdataset))
3953                         dns_rdataset_clone(hevent->rdataset, event->rdataset);
3954                 INSIST(! (hevent->sigrdataset == NULL &&
3955                           event->sigrdataset != NULL));
3956                 if (hevent->sigrdataset != NULL &&
3957                     dns_rdataset_isassociated(hevent->sigrdataset) &&
3958                     event->sigrdataset != NULL)
3959                         dns_rdataset_clone(hevent->sigrdataset,
3960                                            event->sigrdataset);
3961         }
3962 }
3963
3964 #define CACHE(r)        (((r)->attributes & DNS_RDATASETATTR_CACHE) != 0)
3965 #define ANSWER(r)       (((r)->attributes & DNS_RDATASETATTR_ANSWER) != 0)
3966 #define ANSWERSIG(r)    (((r)->attributes & DNS_RDATASETATTR_ANSWERSIG) != 0)
3967 #define EXTERNAL(r)     (((r)->attributes & DNS_RDATASETATTR_EXTERNAL) != 0)
3968 #define CHAINING(r)     (((r)->attributes & DNS_RDATASETATTR_CHAINING) != 0)
3969 #define CHASE(r)        (((r)->attributes & DNS_RDATASETATTR_CHASE) != 0)
3970 #define CHECKNAMES(r)   (((r)->attributes & DNS_RDATASETATTR_CHECKNAMES) != 0)
3971
3972
3973 /*
3974  * Destroy '*fctx' if it is ready to be destroyed (i.e., if it has
3975  * no references and is no longer waiting for any events).
3976  *
3977  * Requires:
3978  *      '*fctx' is shutting down.
3979  *
3980  * Returns:
3981  *      true if the resolver is exiting and this is the last fctx in the bucket.
3982  */
3983 static isc_boolean_t
3984 maybe_destroy(fetchctx_t *fctx, isc_boolean_t locked) {
3985         unsigned int bucketnum;
3986         isc_boolean_t bucket_empty = ISC_FALSE;
3987         dns_resolver_t *res = fctx->res;
3988         dns_validator_t *validator, *next_validator;
3989         isc_boolean_t destroy = ISC_FALSE;
3990
3991         REQUIRE(SHUTTINGDOWN(fctx));
3992
3993         bucketnum = fctx->bucketnum;
3994         if (!locked)
3995                 LOCK(&res->buckets[bucketnum].lock);
3996         if (fctx->pending != 0 || fctx->nqueries != 0)
3997                 goto unlock;
3998
3999         for (validator = ISC_LIST_HEAD(fctx->validators);
4000              validator != NULL; validator = next_validator) {
4001                 next_validator = ISC_LIST_NEXT(validator, link);
4002                 dns_validator_cancel(validator);
4003         }
4004
4005         if (fctx->references == 0 && ISC_LIST_EMPTY(fctx->validators)) {
4006                 bucket_empty = fctx_unlink(fctx);
4007                 destroy = ISC_TRUE;
4008         }
4009  unlock:
4010         if (!locked)
4011                 UNLOCK(&res->buckets[bucketnum].lock);
4012         if (destroy)
4013                 fctx_destroy(fctx);
4014         return (bucket_empty);
4015 }
4016
4017 /*
4018  * The validator has finished.
4019  */
4020 static void
4021 validated(isc_task_t *task, isc_event_t *event) {
4022         dns_adbaddrinfo_t *addrinfo;
4023         dns_dbnode_t *node = NULL;
4024         dns_dbnode_t *nsnode = NULL;
4025         dns_fetchevent_t *hevent;
4026         dns_name_t *name;
4027         dns_rdataset_t *ardataset = NULL;
4028         dns_rdataset_t *asigrdataset = NULL;
4029         dns_rdataset_t *rdataset;
4030         dns_rdataset_t *sigrdataset;
4031         dns_resolver_t *res;
4032         dns_valarg_t *valarg;
4033         dns_validatorevent_t *vevent;
4034         fetchctx_t *fctx;
4035         isc_boolean_t chaining;
4036         isc_boolean_t negative;
4037         isc_boolean_t sentresponse;
4038         isc_result_t eresult = ISC_R_SUCCESS;
4039         isc_result_t result = ISC_R_SUCCESS;
4040         isc_stdtime_t now;
4041         isc_uint32_t ttl;
4042
4043         UNUSED(task); /* for now */
4044
4045         REQUIRE(event->ev_type == DNS_EVENT_VALIDATORDONE);
4046         valarg = event->ev_arg;
4047         fctx = valarg->fctx;
4048         res = fctx->res;
4049         addrinfo = valarg->addrinfo;
4050         REQUIRE(VALID_FCTX(fctx));
4051         REQUIRE(!ISC_LIST_EMPTY(fctx->validators));
4052
4053         vevent = (dns_validatorevent_t *)event;
4054         fctx->vresult = vevent->result;
4055
4056         FCTXTRACE("received validation completion event");
4057
4058         LOCK(&res->buckets[fctx->bucketnum].lock);
4059
4060         ISC_LIST_UNLINK(fctx->validators, vevent->validator, link);
4061         fctx->validator = NULL;
4062
4063         /*
4064          * Destroy the validator early so that we can
4065          * destroy the fctx if necessary.
4066          */
4067         dns_validator_destroy(&vevent->validator);
4068         isc_mem_put(fctx->mctx, valarg, sizeof(*valarg));
4069
4070         negative = ISC_TF(vevent->rdataset == NULL);
4071
4072         sentresponse = ISC_TF((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0);
4073
4074         /*
4075          * If shutting down, ignore the results.  Check to see if we're
4076          * done waiting for validator completions and ADB pending events; if
4077          * so, destroy the fctx.
4078          */
4079         if (SHUTTINGDOWN(fctx) && !sentresponse) {
4080                 isc_uint32_t bucketnum = fctx->bucketnum;
4081                 isc_boolean_t bucket_empty;
4082                 bucket_empty = maybe_destroy(fctx, ISC_TRUE);
4083                 UNLOCK(&res->buckets[bucketnum].lock);
4084                 if (bucket_empty)
4085                         empty_bucket(res);
4086                 goto cleanup_event;
4087         }
4088
4089         isc_stdtime_get(&now);
4090
4091         /*
4092          * If chaining, we need to make sure that the right result code is
4093          * returned, and that the rdatasets are bound.
4094          */
4095         if (vevent->result == ISC_R_SUCCESS &&
4096             !negative &&
4097             vevent->rdataset != NULL &&
4098             CHAINING(vevent->rdataset))
4099         {
4100                 if (vevent->rdataset->type == dns_rdatatype_cname)
4101                         eresult = DNS_R_CNAME;
4102                 else {
4103                         INSIST(vevent->rdataset->type == dns_rdatatype_dname);
4104                         eresult = DNS_R_DNAME;
4105                 }
4106                 chaining = ISC_TRUE;
4107         } else
4108                 chaining = ISC_FALSE;
4109
4110         /*
4111          * Either we're not shutting down, or we are shutting down but want
4112          * to cache the result anyway (if this was a validation started by
4113          * a query with cd set)
4114          */
4115
4116         hevent = ISC_LIST_HEAD(fctx->events);
4117         if (hevent != NULL) {
4118                 if (!negative && !chaining &&
4119                     (fctx->type == dns_rdatatype_any ||
4120                      fctx->type == dns_rdatatype_rrsig ||
4121                      fctx->type == dns_rdatatype_sig)) {
4122                         /*
4123                          * Don't bind rdatasets; the caller
4124                          * will iterate the node.
4125                          */
4126                 } else {
4127                         ardataset = hevent->rdataset;
4128                         asigrdataset = hevent->sigrdataset;
4129                 }
4130         }
4131
4132         if (vevent->result != ISC_R_SUCCESS) {
4133                 FCTXTRACE("validation failed");
4134                 inc_stats(res, dns_resstatscounter_valfail);
4135                 fctx->valfail++;
4136                 fctx->vresult = vevent->result;
4137                 if (fctx->vresult != DNS_R_BROKENCHAIN) {
4138                         result = ISC_R_NOTFOUND;
4139                         if (vevent->rdataset != NULL)
4140                                 result = dns_db_findnode(fctx->cache,
4141                                                          vevent->name,
4142                                                          ISC_TRUE, &node);
4143                         if (result == ISC_R_SUCCESS)
4144                                 (void)dns_db_deleterdataset(fctx->cache, node,
4145                                                              NULL,
4146                                                             vevent->type, 0);
4147                         if (result == ISC_R_SUCCESS &&
4148                              vevent->sigrdataset != NULL)
4149                                 (void)dns_db_deleterdataset(fctx->cache, node,
4150                                                             NULL,
4151                                                             dns_rdatatype_rrsig,
4152                                                             vevent->type);
4153                         if (result == ISC_R_SUCCESS)
4154                                 dns_db_detachnode(fctx->cache, &node);
4155                 }
4156                 if (fctx->vresult == DNS_R_BROKENCHAIN && !negative) {
4157                         /*
4158                          * Cache the data as pending for later validation.
4159                          */
4160                         result = ISC_R_NOTFOUND;
4161                         if (vevent->rdataset != NULL)
4162                                 result = dns_db_findnode(fctx->cache,
4163                                                          vevent->name,
4164                                                          ISC_TRUE, &node);
4165                         if (result == ISC_R_SUCCESS) {
4166                                 (void)dns_db_addrdataset(fctx->cache, node,
4167                                                          NULL, now,
4168                                                          vevent->rdataset, 0,
4169                                                          NULL);
4170                         }
4171                         if (result == ISC_R_SUCCESS &&
4172                             vevent->sigrdataset != NULL)
4173                                 (void)dns_db_addrdataset(fctx->cache, node,
4174                                                          NULL, now,
4175                                                          vevent->sigrdataset,
4176                                                          0, NULL);
4177                         if (result == ISC_R_SUCCESS)
4178                                 dns_db_detachnode(fctx->cache, &node);
4179                 }
4180                 result = fctx->vresult;
4181                 add_bad(fctx, addrinfo, result, badns_validation);
4182                 isc_event_free(&event);
4183                 UNLOCK(&res->buckets[fctx->bucketnum].lock);
4184                 INSIST(fctx->validator == NULL);
4185                 fctx->validator = ISC_LIST_HEAD(fctx->validators);
4186                 if (fctx->validator != NULL)
4187                         dns_validator_send(fctx->validator);
4188                 else if (sentresponse)
4189                         fctx_done(fctx, result, __LINE__); /* Locks bucket. */
4190                 else if (result == DNS_R_BROKENCHAIN) {
4191                         isc_result_t tresult;
4192                         isc_time_t expire;
4193                         isc_interval_t i;
4194
4195                         isc_interval_set(&i, DNS_BADCACHE_TTL(fctx), 0);
4196                         tresult = isc_time_nowplusinterval(&expire, &i);
4197                         if (negative &&
4198                             (fctx->type == dns_rdatatype_dnskey ||
4199                              fctx->type == dns_rdatatype_dlv ||
4200                              fctx->type == dns_rdatatype_ds) &&
4201                              tresult == ISC_R_SUCCESS)
4202                                 dns_resolver_addbadcache(res, &fctx->name,
4203                                                          fctx->type, &expire);
4204                         fctx_done(fctx, result, __LINE__); /* Locks bucket. */
4205                 } else
4206                         fctx_try(fctx, ISC_TRUE, ISC_TRUE); /* Locks bucket. */
4207                 return;
4208         }
4209
4210
4211         if (negative) {
4212                 dns_rdatatype_t covers;
4213                 FCTXTRACE("nonexistence validation OK");
4214
4215                 inc_stats(res, dns_resstatscounter_valnegsuccess);
4216
4217                 if (fctx->rmessage->rcode == dns_rcode_nxdomain)
4218                         covers = dns_rdatatype_any;
4219                 else
4220                         covers = fctx->type;
4221
4222                 result = dns_db_findnode(fctx->cache, vevent->name, ISC_TRUE,
4223                                          &node);
4224                 if (result != ISC_R_SUCCESS)
4225                         goto noanswer_response;
4226
4227                 /*
4228                  * If we are asking for a SOA record set the cache time
4229                  * to zero to facilitate locating the containing zone of
4230                  * a arbitrary zone.
4231                  */
4232                 ttl = res->view->maxncachettl;
4233                 if (fctx->type == dns_rdatatype_soa &&
4234                     covers == dns_rdatatype_any && res->zero_no_soa_ttl)
4235                         ttl = 0;
4236
4237                 result = ncache_adderesult(fctx->rmessage, fctx->cache, node,
4238                                            covers, now, ttl, vevent->optout,
4239                                            vevent->secure, ardataset, &eresult);
4240                 if (result != ISC_R_SUCCESS)
4241                         goto noanswer_response;
4242                 goto answer_response;
4243         } else
4244                 inc_stats(res, dns_resstatscounter_valsuccess);
4245
4246         FCTXTRACE("validation OK");
4247
4248         if (vevent->proofs[DNS_VALIDATOR_NOQNAMEPROOF] != NULL) {
4249                 result = dns_rdataset_addnoqname(vevent->rdataset,
4250                                    vevent->proofs[DNS_VALIDATOR_NOQNAMEPROOF]);
4251                 RUNTIME_CHECK(result == ISC_R_SUCCESS);
4252                 INSIST(vevent->sigrdataset != NULL);
4253                 vevent->sigrdataset->ttl = vevent->rdataset->ttl;
4254                 if (vevent->proofs[DNS_VALIDATOR_CLOSESTENCLOSER] != NULL) {
4255                         result = dns_rdataset_addclosest(vevent->rdataset,
4256                                  vevent->proofs[DNS_VALIDATOR_CLOSESTENCLOSER]);
4257                         RUNTIME_CHECK(result == ISC_R_SUCCESS);
4258                 }
4259         } else if (vevent->rdataset->trust == dns_trust_answer &&
4260                    vevent->rdataset->type != dns_rdatatype_rrsig)
4261         {
4262                 isc_result_t tresult;
4263                 dns_name_t *noqname = NULL;
4264                 tresult = findnoqname(fctx, vevent->name,
4265                                       vevent->rdataset->type, &noqname);
4266                 if (tresult == ISC_R_SUCCESS && noqname != NULL) {
4267                         tresult = dns_rdataset_addnoqname(vevent->rdataset,
4268                                                           noqname);
4269                         RUNTIME_CHECK(tresult == ISC_R_SUCCESS);
4270                 }
4271         }
4272
4273         /*
4274          * The data was already cached as pending data.
4275          * Re-cache it as secure and bind the cached
4276          * rdatasets to the first event on the fetch
4277          * event list.
4278          */
4279         result = dns_db_findnode(fctx->cache, vevent->name, ISC_TRUE, &node);
4280         if (result != ISC_R_SUCCESS)
4281                 goto noanswer_response;
4282
4283         result = dns_db_addrdataset(fctx->cache, node, NULL, now,
4284                                     vevent->rdataset, 0, ardataset);
4285         if (result != ISC_R_SUCCESS &&
4286             result != DNS_R_UNCHANGED)
4287                 goto noanswer_response;
4288         if (ardataset != NULL && NEGATIVE(ardataset)) {
4289                 if (NXDOMAIN(ardataset))
4290                         eresult = DNS_R_NCACHENXDOMAIN;
4291                 else
4292                         eresult = DNS_R_NCACHENXRRSET;
4293         } else if (vevent->sigrdataset != NULL) {
4294                 result = dns_db_addrdataset(fctx->cache, node, NULL, now,
4295                                             vevent->sigrdataset, 0,
4296                                             asigrdataset);
4297                 if (result != ISC_R_SUCCESS &&
4298                     result != DNS_R_UNCHANGED)
4299                         goto noanswer_response;
4300         }
4301
4302         if (sentresponse) {
4303                 isc_boolean_t bucket_empty = ISC_FALSE;
4304                 /*
4305                  * If we only deferred the destroy because we wanted to cache
4306                  * the data, destroy now.
4307                  */
4308                 dns_db_detachnode(fctx->cache, &node);
4309                 if (SHUTTINGDOWN(fctx))
4310                         bucket_empty = maybe_destroy(fctx, ISC_TRUE);
4311                 UNLOCK(&res->buckets[fctx->bucketnum].lock);
4312                 if (bucket_empty)
4313                         empty_bucket(res);
4314                 goto cleanup_event;
4315         }
4316
4317         if (!ISC_LIST_EMPTY(fctx->validators)) {
4318                 INSIST(!negative);
4319                 INSIST(fctx->type == dns_rdatatype_any ||
4320                        fctx->type == dns_rdatatype_rrsig ||
4321                        fctx->type == dns_rdatatype_sig);
4322                 /*
4323                  * Don't send a response yet - we have
4324                  * more rdatasets that still need to
4325                  * be validated.
4326                  */
4327                 dns_db_detachnode(fctx->cache, &node);
4328                 UNLOCK(&res->buckets[fctx->bucketnum].lock);
4329                 dns_validator_send(ISC_LIST_HEAD(fctx->validators));
4330                 goto cleanup_event;
4331         }
4332
4333  answer_response:
4334         /*
4335          * Cache any NS/NSEC records that happened to be validated.
4336          */
4337         result = dns_message_firstname(fctx->rmessage, DNS_SECTION_AUTHORITY);
4338         while (result == ISC_R_SUCCESS) {
4339                 name = NULL;
4340                 dns_message_currentname(fctx->rmessage, DNS_SECTION_AUTHORITY,
4341                                         &name);
4342                 for (rdataset = ISC_LIST_HEAD(name->list);
4343                      rdataset != NULL;
4344                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
4345                         if ((rdataset->type != dns_rdatatype_ns &&
4346                              rdataset->type != dns_rdatatype_nsec) ||
4347                             rdataset->trust != dns_trust_secure)
4348                                 continue;
4349                         for (sigrdataset = ISC_LIST_HEAD(name->list);
4350                              sigrdataset != NULL;
4351                              sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
4352                                 if (sigrdataset->type != dns_rdatatype_rrsig ||
4353                                     sigrdataset->covers != rdataset->type)
4354                                         continue;
4355                                 break;
4356                         }
4357                         if (sigrdataset == NULL ||
4358                             sigrdataset->trust != dns_trust_secure)
4359                                 continue;
4360                         result = dns_db_findnode(fctx->cache, name, ISC_TRUE,
4361                                                  &nsnode);
4362                         if (result != ISC_R_SUCCESS)
4363                                 continue;
4364
4365                         result = dns_db_addrdataset(fctx->cache, nsnode, NULL,
4366                                                     now, rdataset, 0, NULL);
4367                         if (result == ISC_R_SUCCESS)
4368                                 result = dns_db_addrdataset(fctx->cache, nsnode,
4369                                                             NULL, now,
4370                                                             sigrdataset, 0,
4371                                                             NULL);
4372                         dns_db_detachnode(fctx->cache, &nsnode);
4373                         if (result != ISC_R_SUCCESS)
4374                                 continue;
4375                 }
4376                 result = dns_message_nextname(fctx->rmessage,
4377                                               DNS_SECTION_AUTHORITY);
4378         }
4379
4380         result = ISC_R_SUCCESS;
4381
4382         /*
4383          * Respond with an answer, positive or negative,
4384          * as opposed to an error.  'node' must be non-NULL.
4385          */
4386
4387         fctx->attributes |= FCTX_ATTR_HAVEANSWER;
4388
4389         if (hevent != NULL) {
4390                 /*
4391                  * Negative results must be indicated in event->result.
4392                  */
4393                 if (dns_rdataset_isassociated(hevent->rdataset) &&
4394                     NEGATIVE(hevent->rdataset)) {
4395                         INSIST(eresult == DNS_R_NCACHENXDOMAIN ||
4396                                eresult == DNS_R_NCACHENXRRSET);
4397                 }
4398                 hevent->result = eresult;
4399                 RUNTIME_CHECK(dns_name_copy(vevent->name,
4400                               dns_fixedname_name(&hevent->foundname), NULL)
4401                               == ISC_R_SUCCESS);
4402                 dns_db_attach(fctx->cache, &hevent->db);
4403                 dns_db_transfernode(fctx->cache, &node, &hevent->node);
4404                 clone_results(fctx);
4405         }
4406
4407  noanswer_response:
4408         if (node != NULL)
4409                 dns_db_detachnode(fctx->cache, &node);
4410
4411         UNLOCK(&res->buckets[fctx->bucketnum].lock);
4412         fctx_done(fctx, result, __LINE__); /* Locks bucket. */
4413
4414  cleanup_event:
4415         INSIST(node == NULL);
4416         isc_event_free(&event);
4417 }
4418
4419 static void
4420 fctx_log(void *arg, int level, const char *fmt, ...) {
4421         char msgbuf[2048];
4422         va_list args;
4423         fetchctx_t *fctx = arg;
4424
4425         va_start(args, fmt);
4426         vsnprintf(msgbuf, sizeof(msgbuf), fmt, args);
4427         va_end(args);
4428
4429         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
4430                       DNS_LOGMODULE_RESOLVER, level,
4431                       "fctx %p(%s): %s", fctx, fctx->info, msgbuf);
4432 }
4433
4434 static inline isc_result_t
4435 findnoqname(fetchctx_t *fctx, dns_name_t *name, dns_rdatatype_t type,
4436             dns_name_t **noqnamep)
4437 {
4438         dns_rdataset_t *nrdataset, *next, *sigrdataset;
4439         dns_rdata_rrsig_t rrsig;
4440         isc_result_t result;
4441         unsigned int labels;
4442         dns_section_t section;
4443         dns_name_t *zonename;
4444         dns_fixedname_t fzonename;
4445         dns_name_t *closest;
4446         dns_fixedname_t fclosest;
4447         dns_name_t *nearest;
4448         dns_fixedname_t fnearest;
4449         dns_rdatatype_t found = dns_rdatatype_none;
4450         dns_name_t *noqname = NULL;
4451
4452         FCTXTRACE("findnoqname");
4453
4454         REQUIRE(noqnamep != NULL && *noqnamep == NULL);
4455
4456         /*
4457          * Find the SIG for this rdataset, if we have it.
4458          */
4459         for (sigrdataset = ISC_LIST_HEAD(name->list);
4460              sigrdataset != NULL;
4461              sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
4462                 if (sigrdataset->type == dns_rdatatype_rrsig &&
4463                     sigrdataset->covers == type)
4464                         break;
4465         }
4466
4467         if (sigrdataset == NULL)
4468                 return (ISC_R_NOTFOUND);
4469
4470         labels = dns_name_countlabels(name);
4471
4472         for (result = dns_rdataset_first(sigrdataset);
4473              result == ISC_R_SUCCESS;
4474              result = dns_rdataset_next(sigrdataset)) {
4475                 dns_rdata_t rdata = DNS_RDATA_INIT;
4476                 dns_rdataset_current(sigrdataset, &rdata);
4477                 result = dns_rdata_tostruct(&rdata, &rrsig, NULL);
4478                 RUNTIME_CHECK(result == ISC_R_SUCCESS);
4479                 /* Wildcard has rrsig.labels < labels - 1. */
4480                 if (rrsig.labels + 1U >= labels)
4481                         continue;
4482                 break;
4483         }
4484
4485         if (result == ISC_R_NOMORE)
4486                 return (ISC_R_NOTFOUND);
4487         if (result != ISC_R_SUCCESS)
4488                 return (result);
4489
4490         dns_fixedname_init(&fzonename);
4491         zonename = dns_fixedname_name(&fzonename);
4492         dns_fixedname_init(&fclosest);
4493         closest = dns_fixedname_name(&fclosest);
4494         dns_fixedname_init(&fnearest);
4495         nearest = dns_fixedname_name(&fnearest);
4496
4497 #define NXND(x) ((x) == ISC_R_SUCCESS)
4498
4499         section = DNS_SECTION_AUTHORITY;
4500         for (result = dns_message_firstname(fctx->rmessage, section);
4501              result == ISC_R_SUCCESS;
4502              result = dns_message_nextname(fctx->rmessage, section)) {
4503                 dns_name_t *nsec = NULL;
4504                 dns_message_currentname(fctx->rmessage, section, &nsec);
4505                 for (nrdataset = ISC_LIST_HEAD(nsec->list);
4506                       nrdataset != NULL; nrdataset = next) {
4507                         isc_boolean_t data = ISC_FALSE, exists = ISC_FALSE;
4508                         isc_boolean_t optout = ISC_FALSE, unknown = ISC_FALSE;
4509                         isc_boolean_t setclosest = ISC_FALSE;
4510                         isc_boolean_t setnearest = ISC_FALSE;
4511
4512                         next = ISC_LIST_NEXT(nrdataset, link);
4513                         if (nrdataset->type != dns_rdatatype_nsec &&
4514                             nrdataset->type != dns_rdatatype_nsec3)
4515                                 continue;
4516
4517                         if (nrdataset->type == dns_rdatatype_nsec &&
4518                             NXND(dns_nsec_noexistnodata(type, name, nsec,
4519                                                         nrdataset, &exists,
4520                                                         &data, NULL, fctx_log,
4521                                                         fctx)))
4522                         {
4523                                 if (!exists) {
4524                                         noqname = nsec;
4525                                         found = dns_rdatatype_nsec;
4526                                 }
4527                         }
4528
4529                         if (nrdataset->type == dns_rdatatype_nsec3 &&
4530                             NXND(dns_nsec3_noexistnodata(type, name, nsec,
4531                                                          nrdataset, zonename,
4532                                                          &exists, &data,
4533                                                          &optout, &unknown,
4534                                                          &setclosest,
4535                                                          &setnearest,
4536                                                          closest, nearest,
4537                                                          fctx_log, fctx)))
4538                         {
4539                                 if (!exists && setnearest) {
4540                                         noqname = nsec;
4541                                         found = dns_rdatatype_nsec3;
4542                                 }
4543                         }
4544                 }
4545         }
4546         if (result == ISC_R_NOMORE)
4547                 result = ISC_R_SUCCESS;
4548         if (noqname != NULL) {
4549                 for (sigrdataset = ISC_LIST_HEAD(noqname->list);
4550                      sigrdataset != NULL;
4551                      sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
4552                         if (sigrdataset->type == dns_rdatatype_rrsig &&
4553                             sigrdataset->covers == found)
4554                                 break;
4555                 }
4556                 if (sigrdataset != NULL)
4557                         *noqnamep = noqname;
4558         }
4559         return (result);
4560 }
4561
4562 static inline isc_result_t
4563 cache_name(fetchctx_t *fctx, dns_name_t *name, dns_adbaddrinfo_t *addrinfo,
4564            isc_stdtime_t now)
4565 {
4566         dns_rdataset_t *rdataset, *sigrdataset;
4567         dns_rdataset_t *addedrdataset, *ardataset, *asigrdataset;
4568         dns_rdataset_t *valrdataset = NULL, *valsigrdataset = NULL;
4569         dns_dbnode_t *node, **anodep;
4570         dns_db_t **adbp;
4571         dns_name_t *aname;
4572         dns_resolver_t *res;
4573         isc_boolean_t need_validation, secure_domain, have_answer;
4574         isc_result_t result, eresult;
4575         dns_fetchevent_t *event;
4576         unsigned int options;
4577         isc_task_t *task;
4578         isc_boolean_t fail;
4579         unsigned int valoptions = 0;
4580
4581         /*
4582          * The appropriate bucket lock must be held.
4583          */
4584
4585         res = fctx->res;
4586         need_validation = ISC_FALSE;
4587         POST(need_validation);
4588         secure_domain = ISC_FALSE;
4589         have_answer = ISC_FALSE;
4590         eresult = ISC_R_SUCCESS;
4591         task = res->buckets[fctx->bucketnum].task;
4592
4593         /*
4594          * Is DNSSEC validation required for this name?
4595          */
4596         if (res->view->enablevalidation) {
4597                 result = dns_view_issecuredomain(res->view, name,
4598                                                  &secure_domain);
4599                 if (result != ISC_R_SUCCESS)
4600                         return (result);
4601
4602                 if (!secure_domain && res->view->dlv != NULL) {
4603                         valoptions = DNS_VALIDATOR_DLV;
4604                         secure_domain = ISC_TRUE;
4605                 }
4606         }
4607
4608         if ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0)
4609                 need_validation = ISC_FALSE;
4610         else
4611                 need_validation = secure_domain;
4612
4613         adbp = NULL;
4614         aname = NULL;
4615         anodep = NULL;
4616         ardataset = NULL;
4617         asigrdataset = NULL;
4618         event = NULL;
4619         if ((name->attributes & DNS_NAMEATTR_ANSWER) != 0 &&
4620             !need_validation) {
4621                 have_answer = ISC_TRUE;
4622                 event = ISC_LIST_HEAD(fctx->events);
4623                 if (event != NULL) {
4624                         adbp = &event->db;
4625                         aname = dns_fixedname_name(&event->foundname);
4626                         result = dns_name_copy(name, aname, NULL);
4627                         if (result != ISC_R_SUCCESS)
4628                                 return (result);
4629                         anodep = &event->node;
4630                         /*
4631                          * If this is an ANY, SIG or RRSIG query, we're not
4632                          * going to return any rdatasets, unless we encountered
4633                          * a CNAME or DNAME as "the answer".  In this case,
4634                          * we're going to return DNS_R_CNAME or DNS_R_DNAME
4635                          * and we must set up the rdatasets.
4636                          */
4637                         if ((fctx->type != dns_rdatatype_any &&
4638                              fctx->type != dns_rdatatype_rrsig &&
4639                              fctx->type != dns_rdatatype_sig) ||
4640                             (name->attributes & DNS_NAMEATTR_CHAINING) != 0) {
4641                                 ardataset = event->rdataset;
4642                                 asigrdataset = event->sigrdataset;
4643                         }
4644                 }
4645         }
4646
4647         /*
4648          * Find or create the cache node.
4649          */
4650         node = NULL;
4651         result = dns_db_findnode(fctx->cache, name, ISC_TRUE, &node);
4652         if (result != ISC_R_SUCCESS)
4653                 return (result);
4654
4655         /*
4656          * Cache or validate each cacheable rdataset.
4657          */
4658         fail = ISC_TF((fctx->res->options & DNS_RESOLVER_CHECKNAMESFAIL) != 0);
4659         for (rdataset = ISC_LIST_HEAD(name->list);
4660              rdataset != NULL;
4661              rdataset = ISC_LIST_NEXT(rdataset, link)) {
4662                 if (!CACHE(rdataset))
4663                         continue;
4664                 if (CHECKNAMES(rdataset)) {
4665                         char namebuf[DNS_NAME_FORMATSIZE];
4666                         char typebuf[DNS_RDATATYPE_FORMATSIZE];
4667                         char classbuf[DNS_RDATATYPE_FORMATSIZE];
4668
4669                         dns_name_format(name, namebuf, sizeof(namebuf));
4670                         dns_rdatatype_format(rdataset->type, typebuf,
4671                                              sizeof(typebuf));
4672                         dns_rdataclass_format(rdataset->rdclass, classbuf,
4673                                               sizeof(classbuf));
4674                         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
4675                                       DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
4676                                       "check-names %s %s/%s/%s",
4677                                       fail ? "failure" : "warning",
4678                                       namebuf, typebuf, classbuf);
4679                         if (fail) {
4680                                 if (ANSWER(rdataset)) {
4681                                         dns_db_detachnode(fctx->cache, &node);
4682                                         return (DNS_R_BADNAME);
4683                                 }
4684                                 continue;
4685                         }
4686                 }
4687
4688                 /*
4689                  * Enforce the configure maximum cache TTL.
4690                  */
4691                 if (rdataset->ttl > res->view->maxcachettl)
4692                         rdataset->ttl = res->view->maxcachettl;
4693
4694                 /*
4695                  * Find the SIG for this rdataset, if we have it.
4696                  */
4697                 for (sigrdataset = ISC_LIST_HEAD(name->list);
4698                      sigrdataset != NULL;
4699                      sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
4700                         if (sigrdataset->type == dns_rdatatype_rrsig &&
4701                             sigrdataset->covers == rdataset->type)
4702                                 break;
4703                 }
4704
4705                 /*
4706                  * If this RRset is in a secure domain, is in bailiwick,
4707                  * and is not glue, attempt DNSSEC validation.  (We do not
4708                  * attempt to validate glue or out-of-bailiwick data--even
4709                  * though there might be some performance benefit to doing
4710                  * so--because it makes it simpler and safer to ensure that
4711                  * records from a secure domain are only cached if validated
4712                  * within the context of a query to the domain that owns
4713                  * them.)
4714                  */
4715                 if (secure_domain && rdataset->trust != dns_trust_glue &&
4716                     !EXTERNAL(rdataset)) {
4717                         dns_trust_t trust;
4718
4719                         /*
4720                          * RRSIGs are validated as part of validating the
4721                          * type they cover.
4722                          */
4723                         if (rdataset->type == dns_rdatatype_rrsig)
4724                                 continue;
4725
4726                         if (sigrdataset == NULL) {
4727                                 if (!ANSWER(rdataset) && need_validation) {
4728                                         /*
4729                                          * Ignore non-answer rdatasets that
4730                                          * are missing signatures.
4731                                          */
4732                                         continue;
4733                                 }
4734                         }
4735
4736                         /*
4737                          * Normalize the rdataset and sigrdataset TTLs.
4738                          */
4739                         if (sigrdataset != NULL) {
4740                                 rdataset->ttl = ISC_MIN(rdataset->ttl,
4741                                                         sigrdataset->ttl);
4742                                 sigrdataset->ttl = rdataset->ttl;
4743                         }
4744
4745                         /*
4746                          * Cache this rdataset/sigrdataset pair as
4747                          * pending data.  Track whether it was additional
4748                          * or not.
4749                          */
4750                         if (rdataset->trust == dns_trust_additional)
4751                                 trust = dns_trust_pending_additional;
4752                         else
4753                                 trust = dns_trust_pending_answer;
4754
4755                         rdataset->trust = trust;
4756                         if (sigrdataset != NULL)
4757                                 sigrdataset->trust = trust;
4758                         if (!need_validation || !ANSWER(rdataset)) {
4759                                 if (ANSWER(rdataset) &&
4760                                    rdataset->type != dns_rdatatype_rrsig) {
4761                                         isc_result_t tresult;
4762                                         dns_name_t *noqname = NULL;
4763                                         tresult = findnoqname(fctx, name,
4764                                                               rdataset->type,
4765                                                               &noqname);
4766                                         if (tresult == ISC_R_SUCCESS &&
4767                                             noqname != NULL) {
4768                                                 tresult =
4769                                                      dns_rdataset_addnoqname(
4770                                                             rdataset, noqname);
4771                                                 RUNTIME_CHECK(tresult ==
4772                                                               ISC_R_SUCCESS);
4773                                         }
4774                                 }
4775                                 addedrdataset = ardataset;
4776                                 result = dns_db_addrdataset(fctx->cache, node,
4777                                                             NULL, now, rdataset,
4778                                                             0, addedrdataset);
4779                                 if (result == DNS_R_UNCHANGED) {
4780                                         result = ISC_R_SUCCESS;
4781                                         if (!need_validation &&
4782                                             ardataset != NULL &&
4783                                             NEGATIVE(ardataset)) {
4784                                                 /*
4785                                                  * The answer in the cache is
4786                                                  * better than the answer we
4787                                                  * found, and is a negative
4788                                                  * cache entry, so we must set
4789                                                  * eresult appropriately.
4790                                                  */
4791                                                 if (NXDOMAIN(ardataset))
4792                                                         eresult =
4793                                                            DNS_R_NCACHENXDOMAIN;
4794                                                 else
4795                                                         eresult =
4796                                                            DNS_R_NCACHENXRRSET;
4797                                                 /*
4798                                                  * We have a negative response
4799                                                  * from the cache so don't
4800                                                  * attempt to add the RRSIG
4801                                                  * rrset.
4802                                                  */
4803                                                 continue;
4804                                         }
4805                                 }
4806                                 if (result != ISC_R_SUCCESS)
4807                                         break;
4808                                 if (sigrdataset != NULL) {
4809                                         addedrdataset = asigrdataset;
4810                                         result = dns_db_addrdataset(fctx->cache,
4811                                                                 node, NULL, now,
4812                                                                 sigrdataset, 0,
4813                                                                 addedrdataset);
4814                                         if (result == DNS_R_UNCHANGED)
4815                                                 result = ISC_R_SUCCESS;
4816                                         if (result != ISC_R_SUCCESS)
4817                                                 break;
4818                                 } else if (!ANSWER(rdataset))
4819                                         continue;
4820                         }
4821
4822                         if (ANSWER(rdataset) && need_validation) {
4823                                 if (fctx->type != dns_rdatatype_any &&
4824                                     fctx->type != dns_rdatatype_rrsig &&
4825                                     fctx->type != dns_rdatatype_sig) {
4826                                         /*
4827                                          * This is The Answer.  We will
4828                                          * validate it, but first we cache
4829                                          * the rest of the response - it may
4830                                          * contain useful keys.
4831                                          */
4832                                         INSIST(valrdataset == NULL &&
4833                                                valsigrdataset == NULL);
4834                                         valrdataset = rdataset;
4835                                         valsigrdataset = sigrdataset;
4836                                 } else {
4837                                         /*
4838                                          * This is one of (potentially)
4839                                          * multiple answers to an ANY
4840                                          * or SIG query.  To keep things
4841                                          * simple, we just start the
4842                                          * validator right away rather
4843                                          * than caching first and
4844                                          * having to remember which
4845                                          * rdatasets needed validation.
4846                                          */
4847                                         result = valcreate(fctx, addrinfo,
4848                                                            name, rdataset->type,
4849                                                            rdataset,
4850                                                            sigrdataset,
4851                                                            valoptions, task);
4852                                         /*
4853                                          * Defer any further validations.
4854                                          * This prevents multiple validators
4855                                          * from manipulating fctx->rmessage
4856                                          * simultaneously.
4857                                          */
4858                                         valoptions |= DNS_VALIDATOR_DEFER;
4859                                 }
4860                         } else if (CHAINING(rdataset)) {
4861                                 if (rdataset->type == dns_rdatatype_cname)
4862                                         eresult = DNS_R_CNAME;
4863                                 else {
4864                                         INSIST(rdataset->type ==
4865                                                dns_rdatatype_dname);
4866                                         eresult = DNS_R_DNAME;
4867                                 }
4868                         }
4869                 } else if (!EXTERNAL(rdataset)) {
4870                         /*
4871                          * It's OK to cache this rdataset now.
4872                          */
4873                         if (ANSWER(rdataset))
4874                                 addedrdataset = ardataset;
4875                         else if (ANSWERSIG(rdataset))
4876                                 addedrdataset = asigrdataset;
4877                         else
4878                                 addedrdataset = NULL;
4879                         if (CHAINING(rdataset)) {
4880                                 if (rdataset->type == dns_rdatatype_cname)
4881                                         eresult = DNS_R_CNAME;
4882                                 else {
4883                                         INSIST(rdataset->type ==
4884                                                dns_rdatatype_dname);
4885                                         eresult = DNS_R_DNAME;
4886                                 }
4887                         }
4888                         if (rdataset->trust == dns_trust_glue &&
4889                             (rdataset->type == dns_rdatatype_ns ||
4890                              (rdataset->type == dns_rdatatype_rrsig &&
4891                               rdataset->covers == dns_rdatatype_ns))) {
4892                                 /*
4893                                  * If the trust level is 'dns_trust_glue'
4894                                  * then we are adding data from a referral
4895                                  * we got while executing the search algorithm.
4896                                  * New referral data always takes precedence
4897                                  * over the existing cache contents.
4898                                  */
4899                                 options = DNS_DBADD_FORCE;
4900                         } else
4901                                 options = 0;
4902
4903                         if (ANSWER(rdataset) &&
4904                            rdataset->type != dns_rdatatype_rrsig) {
4905                                 isc_result_t tresult;
4906                                 dns_name_t *noqname = NULL;
4907                                 tresult = findnoqname(fctx, name,
4908                                                       rdataset->type, &noqname);
4909                                 if (tresult == ISC_R_SUCCESS &&
4910                                     noqname != NULL) {
4911                                         tresult = dns_rdataset_addnoqname(
4912                                                             rdataset, noqname);
4913                                         RUNTIME_CHECK(tresult == ISC_R_SUCCESS);
4914                                 }
4915                         }
4916
4917                         /*
4918                          * Now we can add the rdataset.
4919                          */
4920                         result = dns_db_addrdataset(fctx->cache,
4921                                                     node, NULL, now,
4922                                                     rdataset,
4923                                                     options,
4924                                                     addedrdataset);
4925
4926                         if (result == DNS_R_UNCHANGED) {
4927                                 if (ANSWER(rdataset) &&
4928                                     ardataset != NULL &&
4929                                     NEGATIVE(ardataset)) {
4930                                         /*
4931                                          * The answer in the cache is better
4932                                          * than the answer we found, and is
4933                                          * a negative cache entry, so we
4934                                          * must set eresult appropriately.
4935                                          */
4936                                         if (NXDOMAIN(ardataset))
4937                                                 eresult = DNS_R_NCACHENXDOMAIN;
4938                                         else
4939                                                 eresult = DNS_R_NCACHENXRRSET;
4940                                 }
4941                                 result = ISC_R_SUCCESS;
4942                         } else if (result != ISC_R_SUCCESS)
4943                                 break;
4944                 }
4945         }
4946
4947         if (valrdataset != NULL)
4948                 result = valcreate(fctx, addrinfo, name, fctx->type,
4949                                    valrdataset, valsigrdataset, valoptions,
4950                                    task);
4951
4952         if (result == ISC_R_SUCCESS && have_answer) {
4953                 fctx->attributes |= FCTX_ATTR_HAVEANSWER;
4954                 if (event != NULL) {
4955                         /*
4956                          * Negative results must be indicated in event->result.
4957                          */
4958                         if (dns_rdataset_isassociated(event->rdataset) &&
4959                             NEGATIVE(event->rdataset)) {
4960                                 INSIST(eresult == DNS_R_NCACHENXDOMAIN ||
4961                                        eresult == DNS_R_NCACHENXRRSET);
4962                         }
4963                         event->result = eresult;
4964                         dns_db_attach(fctx->cache, adbp);
4965                         dns_db_transfernode(fctx->cache, &node, anodep);
4966                         clone_results(fctx);
4967                 }
4968         }
4969
4970         if (node != NULL)
4971                 dns_db_detachnode(fctx->cache, &node);
4972
4973         return (result);
4974 }
4975
4976 static inline isc_result_t
4977 cache_message(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo, isc_stdtime_t now)
4978 {
4979         isc_result_t result;
4980         dns_section_t section;
4981         dns_name_t *name;
4982
4983         FCTXTRACE("cache_message");
4984
4985         fctx->attributes &= ~FCTX_ATTR_WANTCACHE;
4986
4987         LOCK(&fctx->res->buckets[fctx->bucketnum].lock);
4988
4989         for (section = DNS_SECTION_ANSWER;
4990              section <= DNS_SECTION_ADDITIONAL;
4991              section++) {
4992                 result = dns_message_firstname(fctx->rmessage, section);
4993                 while (result == ISC_R_SUCCESS) {
4994                         name = NULL;
4995                         dns_message_currentname(fctx->rmessage, section,
4996                                                 &name);
4997                         if ((name->attributes & DNS_NAMEATTR_CACHE) != 0) {
4998                                 result = cache_name(fctx, name, addrinfo, now);
4999                                 if (result != ISC_R_SUCCESS)
5000                                         break;
5001                         }
5002                         result = dns_message_nextname(fctx->rmessage, section);
5003                 }
5004                 if (result != ISC_R_NOMORE)
5005                         break;
5006         }
5007         if (result == ISC_R_NOMORE)
5008                 result = ISC_R_SUCCESS;
5009
5010         UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
5011
5012         return (result);
5013 }
5014
5015 /*
5016  * Do what dns_ncache_addoptout() does, and then compute an appropriate eresult.
5017  */
5018 static isc_result_t
5019 ncache_adderesult(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node,
5020                   dns_rdatatype_t covers, isc_stdtime_t now, dns_ttl_t maxttl,
5021                   isc_boolean_t optout, isc_boolean_t secure,
5022                   dns_rdataset_t *ardataset, isc_result_t *eresultp)
5023 {
5024         isc_result_t result;
5025         dns_rdataset_t rdataset;
5026
5027         if (ardataset == NULL) {
5028                 dns_rdataset_init(&rdataset);
5029                 ardataset = &rdataset;
5030         }
5031         if (secure)
5032                 result = dns_ncache_addoptout(message, cache, node, covers,
5033                                               now, maxttl, optout, ardataset);
5034         else
5035                 result = dns_ncache_add(message, cache, node, covers, now,
5036                                         maxttl, ardataset);
5037         if (result == DNS_R_UNCHANGED || result == ISC_R_SUCCESS) {
5038                 /*
5039                  * If the cache now contains a negative entry and we
5040                  * care about whether it is DNS_R_NCACHENXDOMAIN or
5041                  * DNS_R_NCACHENXRRSET then extract it.
5042                  */
5043                 if (NEGATIVE(ardataset)) {
5044                         /*
5045                          * The cache data is a negative cache entry.
5046                          */
5047                         if (NXDOMAIN(ardataset))
5048                                 *eresultp = DNS_R_NCACHENXDOMAIN;
5049                         else
5050                                 *eresultp = DNS_R_NCACHENXRRSET;
5051                 } else {
5052                         /*
5053                          * Either we don't care about the nature of the
5054                          * cache rdataset (because no fetch is interested
5055                          * in the outcome), or the cache rdataset is not
5056                          * a negative cache entry.  Whichever case it is,
5057                          * we can return success.
5058                          *
5059                          * XXXRTH  There's a CNAME/DNAME problem here.
5060                          */
5061                         *eresultp = ISC_R_SUCCESS;
5062                 }
5063                 result = ISC_R_SUCCESS;
5064         }
5065         if (ardataset == &rdataset && dns_rdataset_isassociated(ardataset))
5066                 dns_rdataset_disassociate(ardataset);
5067
5068         return (result);
5069 }
5070
5071 static inline isc_result_t
5072 ncache_message(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
5073                dns_rdatatype_t covers, isc_stdtime_t now)
5074 {
5075         isc_result_t result, eresult;
5076         dns_name_t *name;
5077         dns_resolver_t *res;
5078         dns_db_t **adbp;
5079         dns_dbnode_t *node, **anodep;
5080         dns_rdataset_t *ardataset;
5081         isc_boolean_t need_validation, secure_domain;
5082         dns_name_t *aname;
5083         dns_fetchevent_t *event;
5084         isc_uint32_t ttl;
5085         unsigned int valoptions = 0;
5086
5087         FCTXTRACE("ncache_message");
5088
5089         fctx->attributes &= ~FCTX_ATTR_WANTNCACHE;
5090
5091         res = fctx->res;
5092         need_validation = ISC_FALSE;
5093         POST(need_validation);
5094         secure_domain = ISC_FALSE;
5095         eresult = ISC_R_SUCCESS;
5096         name = &fctx->name;
5097         node = NULL;
5098
5099         /*
5100          * XXXMPA remove when we follow cnames and adjust the setting
5101          * of FCTX_ATTR_WANTNCACHE in noanswer_response().
5102          */
5103         INSIST(fctx->rmessage->counts[DNS_SECTION_ANSWER] == 0);
5104
5105         /*
5106          * Is DNSSEC validation required for this name?
5107          */
5108         if (fctx->res->view->enablevalidation) {
5109                 result = dns_view_issecuredomain(res->view, name,
5110                                                  &secure_domain);
5111                 if (result != ISC_R_SUCCESS)
5112                         return (result);
5113
5114                 if (!secure_domain && res->view->dlv != NULL) {
5115                         valoptions = DNS_VALIDATOR_DLV;
5116                         secure_domain = ISC_TRUE;
5117                 }
5118         }
5119
5120         if ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0)
5121                 need_validation = ISC_FALSE;
5122         else
5123                 need_validation = secure_domain;
5124
5125         if (secure_domain) {
5126                 /*
5127                  * Mark all rdatasets as pending.
5128                  */
5129                 dns_rdataset_t *trdataset;
5130                 dns_name_t *tname;
5131
5132                 result = dns_message_firstname(fctx->rmessage,
5133                                                DNS_SECTION_AUTHORITY);
5134                 while (result == ISC_R_SUCCESS) {
5135                         tname = NULL;
5136                         dns_message_currentname(fctx->rmessage,
5137                                                 DNS_SECTION_AUTHORITY,
5138                                                 &tname);
5139                         for (trdataset = ISC_LIST_HEAD(tname->list);
5140                              trdataset != NULL;
5141                              trdataset = ISC_LIST_NEXT(trdataset, link))
5142                                 trdataset->trust = dns_trust_pending_answer;
5143                         result = dns_message_nextname(fctx->rmessage,
5144                                                       DNS_SECTION_AUTHORITY);
5145                 }
5146                 if (result != ISC_R_NOMORE)
5147                         return (result);
5148
5149         }
5150
5151         if (need_validation) {
5152                 /*
5153                  * Do negative response validation.
5154                  */
5155                 result = valcreate(fctx, addrinfo, name, fctx->type,
5156                                    NULL, NULL, valoptions,
5157                                    res->buckets[fctx->bucketnum].task);
5158                 /*
5159                  * If validation is necessary, return now.  Otherwise continue
5160                  * to process the message, letting the validation complete
5161                  * in its own good time.
5162                  */
5163                 return (result);
5164         }
5165
5166         LOCK(&res->buckets[fctx->bucketnum].lock);
5167
5168         adbp = NULL;
5169         aname = NULL;
5170         anodep = NULL;
5171         ardataset = NULL;
5172         if (!HAVE_ANSWER(fctx)) {
5173                 event = ISC_LIST_HEAD(fctx->events);
5174                 if (event != NULL) {
5175                         adbp = &event->db;
5176                         aname = dns_fixedname_name(&event->foundname);
5177                         result = dns_name_copy(name, aname, NULL);
5178                         if (result != ISC_R_SUCCESS)
5179                                 goto unlock;
5180                         anodep = &event->node;
5181                         ardataset = event->rdataset;
5182                 }
5183         } else
5184                 event = NULL;
5185
5186         result = dns_db_findnode(fctx->cache, name, ISC_TRUE, &node);
5187         if (result != ISC_R_SUCCESS)
5188                 goto unlock;
5189
5190         /*
5191          * If we are asking for a SOA record set the cache time
5192          * to zero to facilitate locating the containing zone of
5193          * a arbitrary zone.
5194          */
5195         ttl = fctx->res->view->maxncachettl;
5196         if (fctx->type == dns_rdatatype_soa &&
5197             covers == dns_rdatatype_any &&
5198             fctx->res->zero_no_soa_ttl)
5199                 ttl = 0;
5200
5201         result = ncache_adderesult(fctx->rmessage, fctx->cache, node,
5202                                    covers, now, ttl, ISC_FALSE,
5203                                    ISC_FALSE, ardataset, &eresult);
5204         if (result != ISC_R_SUCCESS)
5205                 goto unlock;
5206
5207         if (!HAVE_ANSWER(fctx)) {
5208                 fctx->attributes |= FCTX_ATTR_HAVEANSWER;
5209                 if (event != NULL) {
5210                         event->result = eresult;
5211                         dns_db_attach(fctx->cache, adbp);
5212                         dns_db_transfernode(fctx->cache, &node, anodep);
5213                         clone_results(fctx);
5214                 }
5215         }
5216
5217  unlock:
5218         UNLOCK(&res->buckets[fctx->bucketnum].lock);
5219
5220         if (node != NULL)
5221                 dns_db_detachnode(fctx->cache, &node);
5222
5223         return (result);
5224 }
5225
5226 static inline void
5227 mark_related(dns_name_t *name, dns_rdataset_t *rdataset,
5228              isc_boolean_t external, isc_boolean_t gluing)
5229 {
5230         name->attributes |= DNS_NAMEATTR_CACHE;
5231         if (gluing) {
5232                 rdataset->trust = dns_trust_glue;
5233                 /*
5234                  * Glue with 0 TTL causes problems.  We force the TTL to
5235                  * 1 second to prevent this.
5236                  */
5237                 if (rdataset->ttl == 0)
5238                         rdataset->ttl = 1;
5239         } else
5240                 rdataset->trust = dns_trust_additional;
5241         /*
5242          * Avoid infinite loops by only marking new rdatasets.
5243          */
5244         if (!CACHE(rdataset)) {
5245                 name->attributes |= DNS_NAMEATTR_CHASE;
5246                 rdataset->attributes |= DNS_RDATASETATTR_CHASE;
5247         }
5248         rdataset->attributes |= DNS_RDATASETATTR_CACHE;
5249         if (external)
5250                 rdataset->attributes |= DNS_RDATASETATTR_EXTERNAL;
5251 }
5252
5253 static isc_result_t
5254 check_section(void *arg, dns_name_t *addname, dns_rdatatype_t type,
5255               dns_section_t section)
5256 {
5257         fetchctx_t *fctx = arg;
5258         isc_result_t result;
5259         dns_name_t *name;
5260         dns_rdataset_t *rdataset;
5261         isc_boolean_t external;
5262         dns_rdatatype_t rtype;
5263         isc_boolean_t gluing;
5264
5265         REQUIRE(VALID_FCTX(fctx));
5266
5267 #if CHECK_FOR_GLUE_IN_ANSWER
5268         if (section == DNS_SECTION_ANSWER && type != dns_rdatatype_a)
5269                 return (ISC_R_SUCCESS);
5270 #endif
5271
5272         if (GLUING(fctx))
5273                 gluing = ISC_TRUE;
5274         else
5275                 gluing = ISC_FALSE;
5276         name = NULL;
5277         rdataset = NULL;
5278         result = dns_message_findname(fctx->rmessage, section, addname,
5279                                       dns_rdatatype_any, 0, &name, NULL);
5280         if (result == ISC_R_SUCCESS) {
5281                 external = ISC_TF(!dns_name_issubdomain(name, &fctx->domain));
5282                 if (type == dns_rdatatype_a) {
5283                         for (rdataset = ISC_LIST_HEAD(name->list);
5284                              rdataset != NULL;
5285                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
5286                                 if (rdataset->type == dns_rdatatype_rrsig)
5287                                         rtype = rdataset->covers;
5288                                 else
5289                                         rtype = rdataset->type;
5290                                 if (rtype == dns_rdatatype_a ||
5291                                     rtype == dns_rdatatype_aaaa)
5292                                         mark_related(name, rdataset, external,
5293                                                      gluing);
5294                         }
5295                 } else {
5296                         result = dns_message_findtype(name, type, 0,
5297                                                       &rdataset);
5298                         if (result == ISC_R_SUCCESS) {
5299                                 mark_related(name, rdataset, external, gluing);
5300                                 /*
5301                                  * Do we have its SIG too?
5302                                  */
5303                                 rdataset = NULL;
5304                                 result = dns_message_findtype(name,
5305                                                       dns_rdatatype_rrsig,
5306                                                       type, &rdataset);
5307                                 if (result == ISC_R_SUCCESS)
5308                                         mark_related(name, rdataset, external,
5309                                                      gluing);
5310                         }
5311                 }
5312         }
5313
5314         return (ISC_R_SUCCESS);
5315 }
5316
5317 static isc_result_t
5318 check_related(void *arg, dns_name_t *addname, dns_rdatatype_t type) {
5319         return (check_section(arg, addname, type, DNS_SECTION_ADDITIONAL));
5320 }
5321
5322 #ifndef CHECK_FOR_GLUE_IN_ANSWER
5323 #define CHECK_FOR_GLUE_IN_ANSWER 0
5324 #endif
5325 #if CHECK_FOR_GLUE_IN_ANSWER
5326 static isc_result_t
5327 check_answer(void *arg, dns_name_t *addname, dns_rdatatype_t type) {
5328         return (check_section(arg, addname, type, DNS_SECTION_ANSWER));
5329 }
5330 #endif
5331
5332 static void
5333 chase_additional(fetchctx_t *fctx) {
5334         isc_boolean_t rescan;
5335         dns_section_t section = DNS_SECTION_ADDITIONAL;
5336         isc_result_t result;
5337
5338  again:
5339         rescan = ISC_FALSE;
5340
5341         for (result = dns_message_firstname(fctx->rmessage, section);
5342              result == ISC_R_SUCCESS;
5343              result = dns_message_nextname(fctx->rmessage, section)) {
5344                 dns_name_t *name = NULL;
5345                 dns_rdataset_t *rdataset;
5346                 dns_message_currentname(fctx->rmessage, DNS_SECTION_ADDITIONAL,
5347                                         &name);
5348                 if ((name->attributes & DNS_NAMEATTR_CHASE) == 0)
5349                         continue;
5350                 name->attributes &= ~DNS_NAMEATTR_CHASE;
5351                 for (rdataset = ISC_LIST_HEAD(name->list);
5352                      rdataset != NULL;
5353                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
5354                         if (CHASE(rdataset)) {
5355                                 rdataset->attributes &= ~DNS_RDATASETATTR_CHASE;
5356                                 (void)dns_rdataset_additionaldata(rdataset,
5357                                                                   check_related,
5358                                                                   fctx);
5359                                 rescan = ISC_TRUE;
5360                         }
5361                 }
5362         }
5363         if (rescan)
5364                 goto again;
5365 }
5366
5367 static inline isc_result_t
5368 cname_target(dns_rdataset_t *rdataset, dns_name_t *tname) {
5369         isc_result_t result;
5370         dns_rdata_t rdata = DNS_RDATA_INIT;
5371         dns_rdata_cname_t cname;
5372
5373         result = dns_rdataset_first(rdataset);
5374         if (result != ISC_R_SUCCESS)
5375                 return (result);
5376         dns_rdataset_current(rdataset, &rdata);
5377         result = dns_rdata_tostruct(&rdata, &cname, NULL);
5378         if (result != ISC_R_SUCCESS)
5379                 return (result);
5380         dns_name_init(tname, NULL);
5381         dns_name_clone(&cname.cname, tname);
5382         dns_rdata_freestruct(&cname);
5383
5384         return (ISC_R_SUCCESS);
5385 }
5386
5387 static inline isc_result_t
5388 dname_target(dns_rdataset_t *rdataset, dns_name_t *qname,
5389              unsigned int nlabels, dns_fixedname_t *fixeddname)
5390 {
5391         isc_result_t result;
5392         dns_rdata_t rdata = DNS_RDATA_INIT;
5393         dns_rdata_dname_t dname;
5394         dns_fixedname_t prefix;
5395
5396         /*
5397          * Get the target name of the DNAME.
5398          */
5399         result = dns_rdataset_first(rdataset);
5400         if (result != ISC_R_SUCCESS)
5401                 return (result);
5402         dns_rdataset_current(rdataset, &rdata);
5403         result = dns_rdata_tostruct(&rdata, &dname, NULL);
5404         if (result != ISC_R_SUCCESS)
5405                 return (result);
5406
5407         dns_fixedname_init(&prefix);
5408         dns_name_split(qname, nlabels, dns_fixedname_name(&prefix), NULL);
5409         dns_fixedname_init(fixeddname);
5410         result = dns_name_concatenate(dns_fixedname_name(&prefix),
5411                                       &dname.dname,
5412                                       dns_fixedname_name(fixeddname), NULL);
5413         dns_rdata_freestruct(&dname);
5414         return (result);
5415 }
5416
5417 static isc_boolean_t
5418 is_answeraddress_allowed(dns_view_t *view, dns_name_t *name,
5419                          dns_rdataset_t *rdataset)
5420 {
5421         isc_result_t result;
5422         dns_rdata_t rdata = DNS_RDATA_INIT;
5423         struct in_addr ina;
5424         struct in6_addr in6a;
5425         isc_netaddr_t netaddr;
5426         char addrbuf[ISC_NETADDR_FORMATSIZE];
5427         char namebuf[DNS_NAME_FORMATSIZE];
5428         char classbuf[64];
5429         char typebuf[64];
5430         int match;
5431
5432         /* By default, we allow any addresses. */
5433         if (view->denyansweracl == NULL)
5434                 return (ISC_TRUE);
5435
5436         /*
5437          * If the owner name matches one in the exclusion list, either exactly
5438          * or partially, allow it.
5439          */
5440         if (view->answeracl_exclude != NULL) {
5441                 dns_rbtnode_t *node = NULL;
5442
5443                 result = dns_rbt_findnode(view->answeracl_exclude, name, NULL,
5444                                           &node, NULL, 0, NULL, NULL);
5445
5446                 if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
5447                         return (ISC_TRUE);
5448         }
5449
5450         /*
5451          * Otherwise, search the filter list for a match for each address
5452          * record.  If a match is found, the address should be filtered,
5453          * so should the entire answer.
5454          */
5455         for (result = dns_rdataset_first(rdataset);
5456              result == ISC_R_SUCCESS;
5457              result = dns_rdataset_next(rdataset)) {
5458                 dns_rdata_reset(&rdata);
5459                 dns_rdataset_current(rdataset, &rdata);
5460                 if (rdataset->type == dns_rdatatype_a) {
5461                         INSIST(rdata.length == sizeof(ina.s_addr));
5462                         memmove(&ina.s_addr, rdata.data, sizeof(ina.s_addr));
5463                         isc_netaddr_fromin(&netaddr, &ina);
5464                 } else {
5465                         INSIST(rdata.length == sizeof(in6a.s6_addr));
5466                         memmove(in6a.s6_addr, rdata.data, sizeof(in6a.s6_addr));
5467                         isc_netaddr_fromin6(&netaddr, &in6a);
5468                 }
5469
5470                 result = dns_acl_match(&netaddr, NULL, view->denyansweracl,
5471                                        &view->aclenv, &match, NULL);
5472
5473                 if (result == ISC_R_SUCCESS && match > 0) {
5474                         isc_netaddr_format(&netaddr, addrbuf, sizeof(addrbuf));
5475                         dns_name_format(name, namebuf, sizeof(namebuf));
5476                         dns_rdatatype_format(rdataset->type, typebuf,
5477                                              sizeof(typebuf));
5478                         dns_rdataclass_format(rdataset->rdclass, classbuf,
5479                                               sizeof(classbuf));
5480                         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
5481                                       DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
5482                                       "answer address %s denied for %s/%s/%s",
5483                                       addrbuf, namebuf, typebuf, classbuf);
5484                         return (ISC_FALSE);
5485                 }
5486         }
5487
5488         return (ISC_TRUE);
5489 }
5490
5491 static isc_boolean_t
5492 is_answertarget_allowed(dns_view_t *view, dns_name_t *name,
5493                         dns_rdatatype_t type, dns_name_t *tname,
5494                         dns_name_t *domain)
5495 {
5496         isc_result_t result;
5497         dns_rbtnode_t *node = NULL;
5498         char qnamebuf[DNS_NAME_FORMATSIZE];
5499         char tnamebuf[DNS_NAME_FORMATSIZE];
5500         char classbuf[64];
5501         char typebuf[64];
5502
5503         /* By default, we allow any target name. */
5504         if (view->denyanswernames == NULL)
5505                 return (ISC_TRUE);
5506
5507         /*
5508          * If the owner name matches one in the exclusion list, either exactly
5509          * or partially, allow it.
5510          */
5511         if (view->answernames_exclude != NULL) {
5512                 result = dns_rbt_findnode(view->answernames_exclude, name, NULL,
5513                                           &node, NULL, 0, NULL, NULL);
5514                 if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
5515                         return (ISC_TRUE);
5516         }
5517
5518         /*
5519          * If the target name is a subdomain of the search domain, allow it.
5520          */
5521         if (dns_name_issubdomain(tname, domain))
5522                 return (ISC_TRUE);
5523
5524         /*
5525          * Otherwise, apply filters.
5526          */
5527         result = dns_rbt_findnode(view->denyanswernames, tname, NULL, &node,
5528                                   NULL, 0, NULL, NULL);
5529         if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
5530                 dns_name_format(name, qnamebuf, sizeof(qnamebuf));
5531                 dns_name_format(tname, tnamebuf, sizeof(tnamebuf));
5532                 dns_rdatatype_format(type, typebuf, sizeof(typebuf));
5533                 dns_rdataclass_format(view->rdclass, classbuf,
5534                                       sizeof(classbuf));
5535                 isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
5536                               DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
5537                               "%s target %s denied for %s/%s",
5538                               typebuf, tnamebuf, qnamebuf, classbuf);
5539                 return (ISC_FALSE);
5540         }
5541
5542         return (ISC_TRUE);
5543 }
5544
5545 static void
5546 trim_ns_ttl(fetchctx_t *fctx, dns_name_t *name, dns_rdataset_t *rdataset) {
5547         char ns_namebuf[DNS_NAME_FORMATSIZE];
5548         char namebuf[DNS_NAME_FORMATSIZE];
5549         char tbuf[DNS_RDATATYPE_FORMATSIZE];
5550
5551         if (fctx->ns_ttl_ok && rdataset->ttl > fctx->ns_ttl) {
5552                 dns_name_format(name, ns_namebuf, sizeof(ns_namebuf));
5553                 dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
5554                 dns_rdatatype_format(fctx->type, tbuf, sizeof(tbuf));
5555
5556                 isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
5557                               DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(10),
5558                               "fctx %p: trimming ttl of %s/NS for %s/%s: "
5559                               "%u -> %u", fctx, ns_namebuf, namebuf, tbuf,
5560                               rdataset->ttl, fctx->ns_ttl);
5561                 rdataset->ttl = fctx->ns_ttl;
5562         }
5563 }
5564
5565 /*
5566  * Handle a no-answer response (NXDOMAIN, NXRRSET, or referral).
5567  * If look_in_options has LOOK_FOR_NS_IN_ANSWER then we look in the answer
5568  * section for the NS RRset if the query type is NS; if it has
5569  * LOOK_FOR_GLUE_IN_ANSWER we look for glue incorrectly returned in the answer
5570  * section for A and AAAA queries.
5571  */
5572 #define LOOK_FOR_NS_IN_ANSWER 0x1
5573 #define LOOK_FOR_GLUE_IN_ANSWER 0x2
5574
5575 static isc_result_t
5576 noanswer_response(fetchctx_t *fctx, dns_name_t *oqname,
5577                   unsigned int look_in_options)
5578 {
5579         isc_result_t result;
5580         dns_message_t *message;
5581         dns_name_t *name, *qname, *ns_name, *soa_name, *ds_name, *save_name;
5582         dns_rdataset_t *rdataset, *ns_rdataset;
5583         isc_boolean_t aa, negative_response;
5584         dns_rdatatype_t type, save_type;
5585         dns_section_t section;
5586
5587         FCTXTRACE("noanswer_response");
5588
5589         if ((look_in_options & LOOK_FOR_NS_IN_ANSWER) != 0) {
5590                 INSIST(fctx->type == dns_rdatatype_ns);
5591                 section = DNS_SECTION_ANSWER;
5592         } else
5593                 section = DNS_SECTION_AUTHORITY;
5594
5595         message = fctx->rmessage;
5596
5597         /*
5598          * Setup qname.
5599          */
5600         if (oqname == NULL) {
5601                 /*
5602                  * We have a normal, non-chained negative response or
5603                  * referral.
5604                  */
5605                 if ((message->flags & DNS_MESSAGEFLAG_AA) != 0)
5606                         aa = ISC_TRUE;
5607                 else
5608                         aa = ISC_FALSE;
5609                 qname = &fctx->name;
5610         } else {
5611                 /*
5612                  * We're being invoked by answer_response() after it has
5613                  * followed a CNAME/DNAME chain.
5614                  */
5615                 qname = oqname;
5616                 aa = ISC_FALSE;
5617                 /*
5618                  * If the current qname is not a subdomain of the query
5619                  * domain, there's no point in looking at the authority
5620                  * section without doing DNSSEC validation.
5621                  *
5622                  * Until we do that validation, we'll just return success
5623                  * in this case.
5624                  */
5625                 if (!dns_name_issubdomain(qname, &fctx->domain))
5626                         return (ISC_R_SUCCESS);
5627         }
5628
5629         /*
5630          * We have to figure out if this is a negative response, or a
5631          * referral.
5632          */
5633
5634         /*
5635          * Sometimes we can tell if its a negative response by looking at
5636          * the message header.
5637          */
5638         negative_response = ISC_FALSE;
5639         if (message->rcode == dns_rcode_nxdomain ||
5640             (message->counts[DNS_SECTION_ANSWER] == 0 &&
5641              message->counts[DNS_SECTION_AUTHORITY] == 0))
5642                 negative_response = ISC_TRUE;
5643
5644         /*
5645          * Process the authority section.
5646          */
5647         ns_name = NULL;
5648         ns_rdataset = NULL;
5649         soa_name = NULL;
5650         ds_name = NULL;
5651         save_name = NULL;
5652         save_type = dns_rdatatype_none;
5653         result = dns_message_firstname(message, section);
5654         while (result == ISC_R_SUCCESS) {
5655                 name = NULL;
5656                 dns_message_currentname(message, section, &name);
5657                 if (dns_name_issubdomain(name, &fctx->domain)) {
5658                         /*
5659                          * Look for NS/SOA RRsets first.
5660                          */
5661                         for (rdataset = ISC_LIST_HEAD(name->list);
5662                              rdataset != NULL;
5663                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
5664                                 type = rdataset->type;
5665                                 if (type == dns_rdatatype_rrsig)
5666                                         type = rdataset->covers;
5667                                 if (((type == dns_rdatatype_ns ||
5668                                       type == dns_rdatatype_soa) &&
5669                                      !dns_name_issubdomain(qname, name))) {
5670                                         char qbuf[DNS_NAME_FORMATSIZE];
5671                                         char nbuf[DNS_NAME_FORMATSIZE];
5672                                         char tbuf[DNS_RDATATYPE_FORMATSIZE];
5673                                         dns_rdatatype_format(fctx->type, tbuf,
5674                                                              sizeof(tbuf));
5675                                         dns_name_format(name, nbuf,
5676                                                              sizeof(nbuf));
5677                                         dns_name_format(qname, qbuf,
5678                                                              sizeof(qbuf));
5679                                         log_formerr(fctx,
5680                                                     "unrelated %s %s in "
5681                                                     "%s authority section",
5682                                                     tbuf, qbuf, nbuf);
5683                                         return (DNS_R_FORMERR);
5684                                 }
5685                                 if (type == dns_rdatatype_ns) {
5686                                         /*
5687                                          * NS or RRSIG NS.
5688                                          *
5689                                          * Only one set of NS RRs is allowed.
5690                                          */
5691                                         if (rdataset->type ==
5692                                             dns_rdatatype_ns) {
5693                                                 if (ns_name != NULL &&
5694                                                     name != ns_name) {
5695                                                         log_formerr(fctx,
5696                                                                 "multiple NS "
5697                                                                 "RRsets in "
5698                                                                 "authority "
5699                                                                 "section");
5700                                                         return (DNS_R_FORMERR);
5701                                                 }
5702                                                 ns_name = name;
5703                                                 ns_rdataset = rdataset;
5704                                         }
5705                                         name->attributes |=
5706                                                 DNS_NAMEATTR_CACHE;
5707                                         rdataset->attributes |=
5708                                                 DNS_RDATASETATTR_CACHE;
5709                                         rdataset->trust = dns_trust_glue;
5710                                 }
5711                                 if (type == dns_rdatatype_soa) {
5712                                         /*
5713                                          * SOA, or RRSIG SOA.
5714                                          *
5715                                          * Only one SOA is allowed.
5716                                          */
5717                                         if (rdataset->type ==
5718                                             dns_rdatatype_soa) {
5719                                                 if (soa_name != NULL &&
5720                                                     name != soa_name) {
5721                                                         log_formerr(fctx,
5722                                                                 "multiple SOA "
5723                                                                 "RRs in "
5724                                                                 "authority "
5725                                                                 "section");
5726                                                         return (DNS_R_FORMERR);
5727                                                 }
5728                                                 soa_name = name;
5729                                         }
5730                                         name->attributes |=
5731                                                 DNS_NAMEATTR_NCACHE;
5732                                         rdataset->attributes |=
5733                                                 DNS_RDATASETATTR_NCACHE;
5734                                         if (aa)
5735                                                 rdataset->trust =
5736                                                     dns_trust_authauthority;
5737                                         else if (ISFORWARDER(fctx->addrinfo))
5738                                                 rdataset->trust =
5739                                                         dns_trust_answer;
5740                                         else
5741                                                 rdataset->trust =
5742                                                         dns_trust_additional;
5743                                 }
5744                         }
5745                 }
5746                 result = dns_message_nextname(message, section);
5747                 if (result == ISC_R_NOMORE)
5748                         break;
5749                 else if (result != ISC_R_SUCCESS)
5750                         return (result);
5751         }
5752
5753         log_ns_ttl(fctx, "noanswer_response");
5754
5755         if (ns_rdataset != NULL && dns_name_equal(&fctx->domain, ns_name) &&
5756             !dns_name_equal(ns_name, dns_rootname))
5757                 trim_ns_ttl(fctx, ns_name, ns_rdataset);
5758
5759         /*
5760          * A negative response has a SOA record (Type 2)
5761          * and a optional NS RRset (Type 1) or it has neither
5762          * a SOA or a NS RRset (Type 3, handled above) or
5763          * rcode is NXDOMAIN (handled above) in which case
5764          * the NS RRset is allowed (Type 4).
5765          */
5766         if (soa_name != NULL)
5767                 negative_response = ISC_TRUE;
5768
5769         result = dns_message_firstname(message, section);
5770         while (result == ISC_R_SUCCESS) {
5771                 name = NULL;
5772                 dns_message_currentname(message, section, &name);
5773                 if (dns_name_issubdomain(name, &fctx->domain)) {
5774                         for (rdataset = ISC_LIST_HEAD(name->list);
5775                              rdataset != NULL;
5776                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
5777                                 type = rdataset->type;
5778                                 if (type == dns_rdatatype_rrsig)
5779                                         type = rdataset->covers;
5780                                 if (type == dns_rdatatype_nsec ||
5781                                     type == dns_rdatatype_nsec3) {
5782                                         /*
5783                                          * NSEC or RRSIG NSEC.
5784                                          */
5785                                         if (negative_response) {
5786                                                 name->attributes |=
5787                                                         DNS_NAMEATTR_NCACHE;
5788                                                 rdataset->attributes |=
5789                                                         DNS_RDATASETATTR_NCACHE;
5790                                         } else if (type == dns_rdatatype_nsec) {
5791                                                 name->attributes |=
5792                                                         DNS_NAMEATTR_CACHE;
5793                                                 rdataset->attributes |=
5794                                                         DNS_RDATASETATTR_CACHE;
5795                                         }
5796                                         if (aa)
5797                                                 rdataset->trust =
5798                                                     dns_trust_authauthority;
5799                                         else if (ISFORWARDER(fctx->addrinfo))
5800                                                 rdataset->trust =
5801                                                         dns_trust_answer;
5802                                         else
5803                                                 rdataset->trust =
5804                                                         dns_trust_additional;
5805                                         /*
5806                                          * No additional data needs to be
5807                                          * marked.
5808                                          */
5809                                 } else if (type == dns_rdatatype_ds) {
5810                                         /*
5811                                          * DS or SIG DS.
5812                                          *
5813                                          * These should only be here if
5814                                          * this is a referral, and there
5815                                          * should only be one DS RRset.
5816                                          */
5817                                         if (ns_name == NULL) {
5818                                                 log_formerr(fctx,
5819                                                             "DS with no "
5820                                                             "referral");
5821                                                 return (DNS_R_FORMERR);
5822                                         }
5823                                         if (rdataset->type ==
5824                                             dns_rdatatype_ds) {
5825                                                 if (ds_name != NULL &&
5826                                                     name != ds_name) {
5827                                                         log_formerr(fctx,
5828                                                                 "DS doesn't "
5829                                                                 "match "
5830                                                                 "referral "
5831                                                                 "(NS)");
5832                                                         return (DNS_R_FORMERR);
5833                                                 }
5834                                                 ds_name = name;
5835                                         }
5836                                         name->attributes |=
5837                                                 DNS_NAMEATTR_CACHE;
5838                                         rdataset->attributes |=
5839                                                 DNS_RDATASETATTR_CACHE;
5840                                         if (aa)
5841                                                 rdataset->trust =
5842                                                     dns_trust_authauthority;
5843                                         else if (ISFORWARDER(fctx->addrinfo))
5844                                                 rdataset->trust =
5845                                                         dns_trust_answer;
5846                                         else
5847                                                 rdataset->trust =
5848                                                         dns_trust_additional;
5849                                 }
5850                         }
5851                 } else {
5852                         save_name = name;
5853                         save_type = ISC_LIST_HEAD(name->list)->type;
5854                 }
5855                 result = dns_message_nextname(message, section);
5856                 if (result == ISC_R_NOMORE)
5857                         break;
5858                 else if (result != ISC_R_SUCCESS)
5859                         return (result);
5860         }
5861
5862         /*
5863          * Trigger lookups for DNS nameservers.
5864          */
5865         if (negative_response && message->rcode == dns_rcode_noerror &&
5866             fctx->type == dns_rdatatype_ds && soa_name != NULL &&
5867             dns_name_equal(soa_name, qname) &&
5868             !dns_name_equal(qname, dns_rootname))
5869                 return (DNS_R_CHASEDSSERVERS);
5870
5871         /*
5872          * Did we find anything?
5873          */
5874         if (!negative_response && ns_name == NULL) {
5875                 /*
5876                  * Nope.
5877                  */
5878                 if (oqname != NULL) {
5879                         /*
5880                          * We've already got a partial CNAME/DNAME chain,
5881                          * and haven't found else anything useful here, but
5882                          * no error has occurred since we have an answer.
5883                          */
5884                         return (ISC_R_SUCCESS);
5885                 } else {
5886                         /*
5887                          * The responder is insane.
5888                          */
5889                         if (save_name == NULL) {
5890                                 log_formerr(fctx, "invalid response");
5891                                 return (DNS_R_FORMERR);
5892                         }
5893                         if (!dns_name_issubdomain(save_name, &fctx->domain)) {
5894                                 char nbuf[DNS_NAME_FORMATSIZE];
5895                                 char dbuf[DNS_NAME_FORMATSIZE];
5896                                 char tbuf[DNS_RDATATYPE_FORMATSIZE];
5897
5898                                 dns_rdatatype_format(save_type, tbuf,
5899                                         sizeof(tbuf));
5900                                 dns_name_format(save_name, nbuf, sizeof(nbuf));
5901                                 dns_name_format(&fctx->domain, dbuf,
5902                                         sizeof(dbuf));
5903
5904                                 log_formerr(fctx, "Name %s (%s) not subdomain"
5905                                         " of zone %s -- invalid response",
5906                                         nbuf, tbuf, dbuf);
5907                         } else {
5908                                 log_formerr(fctx, "invalid response");
5909                         }
5910                         return (DNS_R_FORMERR);
5911                 }
5912         }
5913
5914         /*
5915          * If we found both NS and SOA, they should be the same name.
5916          */
5917         if (ns_name != NULL && soa_name != NULL && ns_name != soa_name) {
5918                 log_formerr(fctx, "NS/SOA mismatch");
5919                 return (DNS_R_FORMERR);
5920         }
5921
5922         /*
5923          * Do we have a referral?  (We only want to follow a referral if
5924          * we're not following a chain.)
5925          */
5926         if (!negative_response && ns_name != NULL && oqname == NULL) {
5927                 /*
5928                  * We already know ns_name is a subdomain of fctx->domain.
5929                  * If ns_name is equal to fctx->domain, we're not making
5930                  * progress.  We return DNS_R_FORMERR so that we'll keep
5931                  * trying other servers.
5932                  */
5933                 if (dns_name_equal(ns_name, &fctx->domain)) {
5934                         log_formerr(fctx, "non-improving referral");
5935                         return (DNS_R_FORMERR);
5936                 }
5937
5938                 /*
5939                  * If the referral name is not a parent of the query
5940                  * name, consider the responder insane.
5941                  */
5942                 if (! dns_name_issubdomain(&fctx->name, ns_name)) {
5943                         /* Logged twice */
5944                         log_formerr(fctx, "referral to non-parent");
5945                         FCTXTRACE("referral to non-parent");
5946                         return (DNS_R_FORMERR);
5947                 }
5948
5949                 /*
5950                  * Mark any additional data related to this rdataset.
5951                  * It's important that we do this before we change the
5952                  * query domain.
5953                  */
5954                 INSIST(ns_rdataset != NULL);
5955                 fctx->attributes |= FCTX_ATTR_GLUING;
5956                 (void)dns_rdataset_additionaldata(ns_rdataset, check_related,
5957                                                   fctx);
5958 #if CHECK_FOR_GLUE_IN_ANSWER
5959                 /*
5960                  * Look in the answer section for "glue" that is incorrectly
5961                  * returned as a answer.  This is needed if the server also
5962                  * minimizes the response size by not adding records to the
5963                  * additional section that are in the answer section or if
5964                  * the record gets dropped due to message size constraints.
5965                  */
5966                 if ((look_in_options & LOOK_FOR_GLUE_IN_ANSWER) != 0 &&
5967                     (fctx->type == dns_rdatatype_aaaa ||
5968                      fctx->type == dns_rdatatype_a))
5969                         (void)dns_rdataset_additionaldata(ns_rdataset,
5970                                                           check_answer, fctx);
5971 #endif
5972                 fctx->attributes &= ~FCTX_ATTR_GLUING;
5973                 /*
5974                  * NS rdatasets with 0 TTL cause problems.
5975                  * dns_view_findzonecut() will not find them when we
5976                  * try to follow the referral, and we'll SERVFAIL
5977                  * because the best nameservers are now above QDOMAIN.
5978                  * We force the TTL to 1 second to prevent this.
5979                  */
5980                 if (ns_rdataset->ttl == 0)
5981                         ns_rdataset->ttl = 1;
5982                 /*
5983                  * Set the current query domain to the referral name.
5984                  *
5985                  * XXXRTH  We should check if we're in forward-only mode, and
5986                  *              if so we should bail out.
5987                  */
5988                 INSIST(dns_name_countlabels(&fctx->domain) > 0);
5989                 dns_name_free(&fctx->domain, fctx->mctx);
5990                 if (dns_rdataset_isassociated(&fctx->nameservers))
5991                         dns_rdataset_disassociate(&fctx->nameservers);
5992                 dns_name_init(&fctx->domain, NULL);
5993                 result = dns_name_dup(ns_name, fctx->mctx, &fctx->domain);
5994                 if (result != ISC_R_SUCCESS)
5995                         return (result);
5996                 fctx->attributes |= FCTX_ATTR_WANTCACHE;
5997                 fctx->ns_ttl_ok = ISC_FALSE;
5998                 log_ns_ttl(fctx, "DELEGATION");
5999                 return (DNS_R_DELEGATION);
6000         }
6001
6002         /*
6003          * Since we're not doing a referral, we don't want to cache any
6004          * NS RRs we may have found.
6005          */
6006         if (ns_name != NULL)
6007                 ns_name->attributes &= ~DNS_NAMEATTR_CACHE;
6008
6009         if (negative_response && oqname == NULL)
6010                 fctx->attributes |= FCTX_ATTR_WANTNCACHE;
6011
6012         return (ISC_R_SUCCESS);
6013 }
6014
6015 static isc_result_t
6016 answer_response(fetchctx_t *fctx) {
6017         isc_result_t result;
6018         dns_message_t *message;
6019         dns_name_t *name, *dname = NULL, *qname, tname, *ns_name;
6020         dns_rdataset_t *rdataset, *ns_rdataset;
6021         isc_boolean_t done, external, chaining, aa, found, want_chaining;
6022         isc_boolean_t have_answer, found_cname, found_type, wanted_chaining;
6023         unsigned int aflag;
6024         dns_rdatatype_t type;
6025         dns_fixedname_t fdname, fqname;
6026         dns_view_t *view;
6027
6028         FCTXTRACE("answer_response");
6029
6030         message = fctx->rmessage;
6031
6032         /*
6033          * Examine the answer section, marking those rdatasets which are
6034          * part of the answer and should be cached.
6035          */
6036
6037         done = ISC_FALSE;
6038         found_cname = ISC_FALSE;
6039         found_type = ISC_FALSE;
6040         chaining = ISC_FALSE;
6041         have_answer = ISC_FALSE;
6042         want_chaining = ISC_FALSE;
6043         POST(want_chaining);
6044         if ((message->flags & DNS_MESSAGEFLAG_AA) != 0)
6045                 aa = ISC_TRUE;
6046         else
6047                 aa = ISC_FALSE;
6048         qname = &fctx->name;
6049         type = fctx->type;
6050         view = fctx->res->view;
6051         result = dns_message_firstname(message, DNS_SECTION_ANSWER);
6052         while (!done && result == ISC_R_SUCCESS) {
6053                 dns_namereln_t namereln;
6054                 int order;
6055                 unsigned int nlabels;
6056
6057                 name = NULL;
6058                 dns_message_currentname(message, DNS_SECTION_ANSWER, &name);
6059                 external = ISC_TF(!dns_name_issubdomain(name, &fctx->domain));
6060                 namereln = dns_name_fullcompare(qname, name, &order, &nlabels);
6061                 if (namereln == dns_namereln_equal) {
6062                         wanted_chaining = ISC_FALSE;
6063                         for (rdataset = ISC_LIST_HEAD(name->list);
6064                              rdataset != NULL;
6065                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
6066                                 found = ISC_FALSE;
6067                                 want_chaining = ISC_FALSE;
6068                                 aflag = 0;
6069                                 if (rdataset->type == dns_rdatatype_nsec3) {
6070                                         /*
6071                                          * NSEC3 records are not allowed to
6072                                          * appear in the answer section.
6073                                          */
6074                                         log_formerr(fctx, "NSEC3 in answer");
6075                                         return (DNS_R_FORMERR);
6076                                 }
6077
6078                                 /*
6079                                  * Apply filters, if given, on answers to reject
6080                                  * a malicious attempt of rebinding.
6081                                  */
6082                                 if ((rdataset->type == dns_rdatatype_a ||
6083                                      rdataset->type == dns_rdatatype_aaaa) &&
6084                                     !is_answeraddress_allowed(view, name,
6085                                                               rdataset)) {
6086                                         return (DNS_R_SERVFAIL);
6087                                 }
6088
6089                                 if (rdataset->type == type && !found_cname) {
6090                                         /*
6091                                          * We've found an ordinary answer.
6092                                          */
6093                                         found = ISC_TRUE;
6094                                         found_type = ISC_TRUE;
6095                                         done = ISC_TRUE;
6096                                         aflag = DNS_RDATASETATTR_ANSWER;
6097                                 } else if (type == dns_rdatatype_any) {
6098                                         /*
6099                                          * We've found an answer matching
6100                                          * an ANY query.  There may be
6101                                          * more.
6102                                          */
6103                                         found = ISC_TRUE;
6104                                         aflag = DNS_RDATASETATTR_ANSWER;
6105                                 } else if (rdataset->type == dns_rdatatype_rrsig
6106                                            && rdataset->covers == type
6107                                            && !found_cname) {
6108                                         /*
6109                                          * We've found a signature that
6110                                          * covers the type we're looking for.
6111                                          */
6112                                         found = ISC_TRUE;
6113                                         found_type = ISC_TRUE;
6114                                         aflag = DNS_RDATASETATTR_ANSWERSIG;
6115                                 } else if (rdataset->type ==
6116                                            dns_rdatatype_cname
6117                                            && !found_type) {
6118                                         /*
6119                                          * We're looking for something else,
6120                                          * but we found a CNAME.
6121                                          *
6122                                          * Getting a CNAME response for some
6123                                          * query types is an error, see
6124                                          * RFC 4035, Section 2.5.
6125                                          */
6126                                         if (type == dns_rdatatype_rrsig ||
6127                                             type == dns_rdatatype_key ||
6128                                             type == dns_rdatatype_nsec) {
6129                                                 char buf[DNS_RDATATYPE_FORMATSIZE];
6130                                                 dns_rdatatype_format(fctx->type,
6131                                                               buf, sizeof(buf));
6132                                                 log_formerr(fctx,
6133                                                             "CNAME response "
6134                                                             "for %s RR", buf);
6135                                                 return (DNS_R_FORMERR);
6136                                         }
6137                                         found = ISC_TRUE;
6138                                         found_cname = ISC_TRUE;
6139                                         want_chaining = ISC_TRUE;
6140                                         aflag = DNS_RDATASETATTR_ANSWER;
6141                                         result = cname_target(rdataset,
6142                                                               &tname);
6143                                         if (result != ISC_R_SUCCESS)
6144                                                 return (result);
6145                                         /* Apply filters on the target name. */
6146                                         if (!is_answertarget_allowed(view,
6147                                                         name,
6148                                                         rdataset->type,
6149                                                         &tname,
6150                                                         &fctx->domain)) {
6151                                                 return (DNS_R_SERVFAIL);
6152                                         }
6153                                 } else if (rdataset->type == dns_rdatatype_rrsig
6154                                            && rdataset->covers ==
6155                                            dns_rdatatype_cname
6156                                            && !found_type) {
6157                                         /*
6158                                          * We're looking for something else,
6159                                          * but we found a SIG CNAME.
6160                                          */
6161                                         found = ISC_TRUE;
6162                                         found_cname = ISC_TRUE;
6163                                         aflag = DNS_RDATASETATTR_ANSWERSIG;
6164                                 }
6165
6166                                 if (found) {
6167                                         /*
6168                                          * We've found an answer to our
6169                                          * question.
6170                                          */
6171                                         name->attributes |=
6172                                                 DNS_NAMEATTR_CACHE;
6173                                         rdataset->attributes |=
6174                                                 DNS_RDATASETATTR_CACHE;
6175                                         rdataset->trust = dns_trust_answer;
6176                                         if (!chaining) {
6177                                                 /*
6178                                                  * This data is "the" answer
6179                                                  * to our question only if
6180                                                  * we're not chaining (i.e.
6181                                                  * if we haven't followed
6182                                                  * a CNAME or DNAME).
6183                                                  */
6184                                                 INSIST(!external);
6185                                                 if (aflag ==
6186                                                     DNS_RDATASETATTR_ANSWER) {
6187                                                         have_answer = ISC_TRUE;
6188                                                         name->attributes |=
6189                                                                 DNS_NAMEATTR_ANSWER;
6190                                                 }
6191                                                 rdataset->attributes |= aflag;
6192                                                 if (aa)
6193                                                         rdataset->trust =
6194                                                           dns_trust_authanswer;
6195                                         } else if (external) {
6196                                                 /*
6197                                                  * This data is outside of
6198                                                  * our query domain, and
6199                                                  * may not be cached.
6200                                                  */
6201                                                 rdataset->attributes |=
6202                                                     DNS_RDATASETATTR_EXTERNAL;
6203                                         }
6204
6205                                         /*
6206                                          * Mark any additional data related
6207                                          * to this rdataset.
6208                                          */
6209                                         (void)dns_rdataset_additionaldata(
6210                                                         rdataset,
6211                                                         check_related,
6212                                                         fctx);
6213
6214                                         /*
6215                                          * CNAME chaining.
6216                                          */
6217                                         if (want_chaining) {
6218                                                 wanted_chaining = ISC_TRUE;
6219                                                 name->attributes |=
6220                                                         DNS_NAMEATTR_CHAINING;
6221                                                 rdataset->attributes |=
6222                                                     DNS_RDATASETATTR_CHAINING;
6223                                                 qname = &tname;
6224                                         }
6225                                 }
6226                                 /*
6227                                  * We could add an "else" clause here and
6228                                  * log that we're ignoring this rdataset.
6229                                  */
6230                         }
6231                         /*
6232                          * If wanted_chaining is true, we've done
6233                          * some chaining as the result of processing
6234                          * this node, and thus we need to set
6235                          * chaining to true.
6236                          *
6237                          * We don't set chaining inside of the
6238                          * rdataset loop because doing that would
6239                          * cause us to ignore the signatures of
6240                          * CNAMEs.
6241                          */
6242                         if (wanted_chaining)
6243                                 chaining = ISC_TRUE;
6244                 } else {
6245                         dns_rdataset_t *dnameset = NULL;
6246
6247                         /*
6248                          * Look for a DNAME (or its SIG).  Anything else is
6249                          * ignored.
6250                          */
6251                         wanted_chaining = ISC_FALSE;
6252                         for (rdataset = ISC_LIST_HEAD(name->list);
6253                              rdataset != NULL;
6254                              rdataset = ISC_LIST_NEXT(rdataset, link))
6255                         {
6256                                 /*
6257                                  * Only pass DNAME or RRSIG(DNAME).
6258                                  */
6259                                 if (rdataset->type != dns_rdatatype_dname &&
6260                                     (rdataset->type != dns_rdatatype_rrsig ||
6261                                      rdataset->covers != dns_rdatatype_dname))
6262                                         continue;
6263
6264                                 /*
6265                                  * If we're not chaining, then the DNAME and
6266                                  * its signature should not be external.
6267                                  */
6268                                 if (!chaining && external) {
6269                                         char qbuf[DNS_NAME_FORMATSIZE];
6270                                         char obuf[DNS_NAME_FORMATSIZE];
6271
6272                                         dns_name_format(name, qbuf,
6273                                                         sizeof(qbuf));
6274                                         dns_name_format(&fctx->domain, obuf,
6275                                                         sizeof(obuf));
6276                                         log_formerr(fctx, "external DNAME or "
6277                                                     "RRSIG covering DNAME "
6278                                                     "in answer: %s is "
6279                                                     "not in %s", qbuf, obuf);
6280                                         return (DNS_R_FORMERR);
6281                                 }
6282
6283                                 if (namereln != dns_namereln_subdomain) {
6284                                         char qbuf[DNS_NAME_FORMATSIZE];
6285                                         char obuf[DNS_NAME_FORMATSIZE];
6286
6287                                         dns_name_format(qname, qbuf,
6288                                                         sizeof(qbuf));
6289                                         dns_name_format(name, obuf,
6290                                                         sizeof(obuf));
6291                                         log_formerr(fctx, "unrelated DNAME "
6292                                                     "in answer: %s is "
6293                                                     "not in %s", qbuf, obuf);
6294                                         return (DNS_R_FORMERR);
6295                                 }
6296
6297                                 aflag = 0;
6298                                 if (rdataset->type == dns_rdatatype_dname) {
6299                                         want_chaining = ISC_TRUE;
6300                                         POST(want_chaining);
6301                                         aflag = DNS_RDATASETATTR_ANSWER;
6302                                         result = dname_target(rdataset, qname,
6303                                                               nlabels, &fdname);
6304                                         if (result == ISC_R_NOSPACE) {
6305                                                 /*
6306                                                  * We can't construct the
6307                                                  * DNAME target.  Do not
6308                                                  * try to continue.
6309                                                  */
6310                                                 want_chaining = ISC_FALSE;
6311                                                 POST(want_chaining);
6312                                         } else if (result != ISC_R_SUCCESS)
6313                                                 return (result);
6314                                         else
6315                                                 dnameset = rdataset;
6316
6317                                         dname = dns_fixedname_name(&fdname);
6318                                         if (!is_answertarget_allowed(view,
6319                                                         qname, rdataset->type,
6320                                                         dname, &fctx->domain)) {
6321                                                 return (DNS_R_SERVFAIL);
6322                                         }
6323                                 } else {
6324                                         /*
6325                                          * We've found a signature that
6326                                          * covers the DNAME.
6327                                          */
6328                                         aflag = DNS_RDATASETATTR_ANSWERSIG;
6329                                 }
6330
6331                                 /*
6332                                  * We've found an answer to our
6333                                  * question.
6334                                  */
6335                                 name->attributes |= DNS_NAMEATTR_CACHE;
6336                                 rdataset->attributes |= DNS_RDATASETATTR_CACHE;
6337                                 rdataset->trust = dns_trust_answer;
6338                                 if (!chaining) {
6339                                         /*
6340                                          * This data is "the" answer to
6341                                          * our question only if we're
6342                                          * not chaining.
6343                                          */
6344                                         INSIST(!external);
6345                                         if (aflag == DNS_RDATASETATTR_ANSWER) {
6346                                                 have_answer = ISC_TRUE;
6347                                                 name->attributes |=
6348                                                         DNS_NAMEATTR_ANSWER;
6349                                         }
6350                                         rdataset->attributes |= aflag;
6351                                         if (aa)
6352                                                 rdataset->trust =
6353                                                   dns_trust_authanswer;
6354                                 } else if (external) {
6355                                         rdataset->attributes |=
6356                                             DNS_RDATASETATTR_EXTERNAL;
6357                                 }
6358                         }
6359
6360                         /*
6361                          * DNAME chaining.
6362                          */
6363                         if (dnameset != NULL) {
6364                                 /*
6365                                  * Copy the dname into the qname fixed name.
6366                                  *
6367                                  * Although we check for failure of the copy
6368                                  * operation, in practice it should never fail
6369                                  * since we already know that the  result fits
6370                                  * in a fixedname.
6371                                  */
6372                                 dns_fixedname_init(&fqname);
6373                                 qname = dns_fixedname_name(&fqname);
6374                                 result = dns_name_copy(dname, qname, NULL);
6375                                 if (result != ISC_R_SUCCESS)
6376                                         return (result);
6377                                 wanted_chaining = ISC_TRUE;
6378                                 name->attributes |= DNS_NAMEATTR_CHAINING;
6379                                 dnameset->attributes |=
6380                                             DNS_RDATASETATTR_CHAINING;
6381                         }
6382                         if (wanted_chaining)
6383                                 chaining = ISC_TRUE;
6384                 }
6385                 result = dns_message_nextname(message, DNS_SECTION_ANSWER);
6386         }
6387         if (result == ISC_R_NOMORE)
6388                 result = ISC_R_SUCCESS;
6389         if (result != ISC_R_SUCCESS)
6390                 return (result);
6391
6392         /*
6393          * We should have found an answer.
6394          */
6395         if (!have_answer) {
6396                 log_formerr(fctx, "reply has no answer");
6397                 return (DNS_R_FORMERR);
6398         }
6399
6400         /*
6401          * This response is now potentially cacheable.
6402          */
6403         fctx->attributes |= FCTX_ATTR_WANTCACHE;
6404
6405         /*
6406          * Did chaining end before we got the final answer?
6407          */
6408         if (chaining) {
6409                 /*
6410                  * Yes.  This may be a negative reply, so hand off
6411                  * authority section processing to the noanswer code.
6412                  * If it isn't a noanswer response, no harm will be
6413                  * done.
6414                  */
6415                 return (noanswer_response(fctx, qname, 0));
6416         }
6417
6418         /*
6419          * We didn't end with an incomplete chain, so the rcode should be
6420          * "no error".
6421          */
6422         if (message->rcode != dns_rcode_noerror) {
6423                 log_formerr(fctx, "CNAME/DNAME chain complete, but RCODE "
6424                                   "indicates error");
6425                 return (DNS_R_FORMERR);
6426         }
6427
6428         /*
6429          * Examine the authority section (if there is one).
6430          *
6431          * We expect there to be only one owner name for all the rdatasets
6432          * in this section, and we expect that it is not external.
6433          */
6434         done = ISC_FALSE;
6435         ns_name = NULL;
6436         ns_rdataset = NULL;
6437         result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
6438         while (!done && result == ISC_R_SUCCESS) {
6439                 name = NULL;
6440                 dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
6441                 external = ISC_TF(!dns_name_issubdomain(name, &fctx->domain));
6442                 if (!external) {
6443                         /*
6444                          * We expect to find NS or SIG NS rdatasets, and
6445                          * nothing else.
6446                          */
6447                         for (rdataset = ISC_LIST_HEAD(name->list);
6448                              rdataset != NULL;
6449                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
6450                                 if (rdataset->type == dns_rdatatype_ns ||
6451                                     (rdataset->type == dns_rdatatype_rrsig &&
6452                                      rdataset->covers == dns_rdatatype_ns)) {
6453                                         name->attributes |=
6454                                                 DNS_NAMEATTR_CACHE;
6455                                         rdataset->attributes |=
6456                                                 DNS_RDATASETATTR_CACHE;
6457                                         if (aa && !chaining)
6458                                                 rdataset->trust =
6459                                                     dns_trust_authauthority;
6460                                         else
6461                                                 rdataset->trust =
6462                                                     dns_trust_additional;
6463
6464                                         if (rdataset->type == dns_rdatatype_ns) {
6465                                                 ns_name = name;
6466                                                 ns_rdataset = rdataset;
6467                                         }
6468                                         /*
6469                                          * Mark any additional data related
6470                                          * to this rdataset.
6471                                          */
6472                                         (void)dns_rdataset_additionaldata(
6473                                                         rdataset,
6474                                                         check_related,
6475                                                         fctx);
6476                                         done = ISC_TRUE;
6477                                 }
6478                         }
6479                 }
6480                 result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
6481         }
6482         if (result == ISC_R_NOMORE)
6483                 result = ISC_R_SUCCESS;
6484
6485         log_ns_ttl(fctx, "answer_response");
6486
6487         if (ns_rdataset != NULL && dns_name_equal(&fctx->domain, ns_name) &&
6488             !dns_name_equal(ns_name, dns_rootname))
6489                 trim_ns_ttl(fctx, ns_name, ns_rdataset);
6490
6491         return (result);
6492 }
6493
6494 static isc_boolean_t
6495 fctx_decreference(fetchctx_t *fctx) {
6496         isc_boolean_t bucket_empty = ISC_FALSE;
6497
6498         INSIST(fctx->references > 0);
6499         fctx->references--;
6500         if (fctx->references == 0) {
6501                 /*
6502                  * No one cares about the result of this fetch anymore.
6503                  */
6504                 if (fctx->pending == 0 && fctx->nqueries == 0 &&
6505                     ISC_LIST_EMPTY(fctx->validators) && SHUTTINGDOWN(fctx)) {
6506                         /*
6507                          * This fctx is already shutdown; we were just
6508                          * waiting for the last reference to go away.
6509                          */
6510                         bucket_empty = fctx_unlink(fctx);
6511                         fctx_destroy(fctx);
6512                 } else {
6513                         /*
6514                          * Initiate shutdown.
6515                          */
6516                         fctx_shutdown(fctx);
6517                 }
6518         }
6519         return (bucket_empty);
6520 }
6521
6522 static void
6523 resume_dslookup(isc_task_t *task, isc_event_t *event) {
6524         dns_fetchevent_t *fevent;
6525         dns_resolver_t *res;
6526         fetchctx_t *fctx;
6527         isc_result_t result;
6528         isc_boolean_t bucket_empty;
6529         isc_boolean_t locked = ISC_FALSE;
6530         unsigned int bucketnum;
6531         dns_rdataset_t nameservers;
6532         dns_fixedname_t fixed;
6533         dns_name_t *domain;
6534
6535         REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE);
6536         fevent = (dns_fetchevent_t *)event;
6537         fctx = event->ev_arg;
6538         REQUIRE(VALID_FCTX(fctx));
6539         res = fctx->res;
6540
6541         UNUSED(task);
6542         FCTXTRACE("resume_dslookup");
6543
6544         if (fevent->node != NULL)
6545                 dns_db_detachnode(fevent->db, &fevent->node);
6546         if (fevent->db != NULL)
6547                 dns_db_detach(&fevent->db);
6548
6549         dns_rdataset_init(&nameservers);
6550
6551         bucketnum = fctx->bucketnum;
6552         if (fevent->result == ISC_R_CANCELED) {
6553                 dns_resolver_destroyfetch(&fctx->nsfetch);
6554                 fctx_done(fctx, ISC_R_CANCELED, __LINE__);
6555         } else if (fevent->result == ISC_R_SUCCESS) {
6556
6557                 FCTXTRACE("resuming DS lookup");
6558
6559                 dns_resolver_destroyfetch(&fctx->nsfetch);
6560                 if (dns_rdataset_isassociated(&fctx->nameservers))
6561                         dns_rdataset_disassociate(&fctx->nameservers);
6562                 dns_rdataset_clone(fevent->rdataset, &fctx->nameservers);
6563                 fctx->ns_ttl = fctx->nameservers.ttl;
6564                 fctx->ns_ttl_ok = ISC_TRUE;
6565                 log_ns_ttl(fctx, "resume_dslookup");
6566                 dns_name_free(&fctx->domain, fctx->mctx);
6567                 dns_name_init(&fctx->domain, NULL);
6568                 result = dns_name_dup(&fctx->nsname, fctx->mctx, &fctx->domain);
6569                 if (result != ISC_R_SUCCESS) {
6570                         fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
6571                         goto cleanup;
6572                 }
6573                 /*
6574                  * Try again.
6575                  */
6576                 fctx_try(fctx, ISC_TRUE, ISC_FALSE);
6577         } else {
6578                 unsigned int n;
6579                 dns_rdataset_t *nsrdataset = NULL;
6580
6581                 /*
6582                  * Retrieve state from fctx->nsfetch before we destroy it.
6583                  */
6584                 dns_fixedname_init(&fixed);
6585                 domain = dns_fixedname_name(&fixed);
6586                 dns_name_copy(&fctx->nsfetch->private->domain, domain, NULL);
6587                 if (dns_name_equal(&fctx->nsname, domain)) {
6588                         fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
6589                         dns_resolver_destroyfetch(&fctx->nsfetch);
6590                         goto cleanup;
6591                 }
6592                 if (dns_rdataset_isassociated(
6593                     &fctx->nsfetch->private->nameservers)) {
6594                         dns_rdataset_clone(
6595                             &fctx->nsfetch->private->nameservers,
6596                             &nameservers);
6597                         nsrdataset = &nameservers;
6598                 } else
6599                         domain = NULL;
6600                 dns_resolver_destroyfetch(&fctx->nsfetch);
6601                 n = dns_name_countlabels(&fctx->nsname);
6602                 dns_name_getlabelsequence(&fctx->nsname, 1, n - 1,
6603                                           &fctx->nsname);
6604
6605                 if (dns_rdataset_isassociated(fevent->rdataset))
6606                         dns_rdataset_disassociate(fevent->rdataset);
6607                 FCTXTRACE("continuing to look for parent's NS records");
6608                 result = dns_resolver_createfetch(fctx->res, &fctx->nsname,
6609                                                   dns_rdatatype_ns, domain,
6610                                                   nsrdataset, NULL, 0, task,
6611                                                   resume_dslookup, fctx,
6612                                                   &fctx->nsrrset, NULL,
6613                                                   &fctx->nsfetch);
6614                 if (result != ISC_R_SUCCESS)
6615                         fctx_done(fctx, result, __LINE__);
6616                 else {
6617                         LOCK(&res->buckets[bucketnum].lock);
6618                         locked = ISC_TRUE;
6619                         fctx->references++;
6620                 }
6621         }
6622
6623  cleanup:
6624         if (dns_rdataset_isassociated(&nameservers))
6625                 dns_rdataset_disassociate(&nameservers);
6626         if (dns_rdataset_isassociated(fevent->rdataset))
6627                 dns_rdataset_disassociate(fevent->rdataset);
6628         INSIST(fevent->sigrdataset == NULL);
6629         isc_event_free(&event);
6630         if (!locked)
6631                 LOCK(&res->buckets[bucketnum].lock);
6632         bucket_empty = fctx_decreference(fctx);
6633         UNLOCK(&res->buckets[bucketnum].lock);
6634         if (bucket_empty)
6635                 empty_bucket(res);
6636 }
6637
6638 static inline void
6639 checknamessection(dns_message_t *message, dns_section_t section) {
6640         isc_result_t result;
6641         dns_name_t *name;
6642         dns_rdata_t rdata = DNS_RDATA_INIT;
6643         dns_rdataset_t *rdataset;
6644
6645         for (result = dns_message_firstname(message, section);
6646              result == ISC_R_SUCCESS;
6647              result = dns_message_nextname(message, section))
6648         {
6649                 name = NULL;
6650                 dns_message_currentname(message, section, &name);
6651                 for (rdataset = ISC_LIST_HEAD(name->list);
6652                      rdataset != NULL;
6653                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
6654                         for (result = dns_rdataset_first(rdataset);
6655                              result == ISC_R_SUCCESS;
6656                              result = dns_rdataset_next(rdataset)) {
6657                                 dns_rdataset_current(rdataset, &rdata);
6658                                 if (!dns_rdata_checkowner(name, rdata.rdclass,
6659                                                           rdata.type,
6660                                                           ISC_FALSE) ||
6661                                     !dns_rdata_checknames(&rdata, name, NULL))
6662                                 {
6663                                         rdataset->attributes |=
6664                                                 DNS_RDATASETATTR_CHECKNAMES;
6665                                 }
6666                                 dns_rdata_reset(&rdata);
6667                         }
6668                 }
6669         }
6670 }
6671
6672 static void
6673 checknames(dns_message_t *message) {
6674
6675         checknamessection(message, DNS_SECTION_ANSWER);
6676         checknamessection(message, DNS_SECTION_AUTHORITY);
6677         checknamessection(message, DNS_SECTION_ADDITIONAL);
6678 }
6679
6680 /*
6681  * Log server NSID at log level 'level'
6682  */
6683 static void
6684 log_nsid(isc_buffer_t *opt, size_t nsid_len, resquery_t *query,
6685          int level, isc_mem_t *mctx)
6686 {
6687         static const char hex[17] = "0123456789abcdef";
6688         char addrbuf[ISC_SOCKADDR_FORMATSIZE];
6689         isc_uint16_t buflen, i;
6690         unsigned char *p, *buf, *nsid;
6691
6692         /* Allocate buffer for storing hex version of the NSID */
6693         buflen = (isc_uint16_t)nsid_len * 2 + 1;
6694         buf = isc_mem_get(mctx, buflen);
6695         if (buf == NULL)
6696                 return;
6697
6698         /* Convert to hex */
6699         p = buf;
6700         nsid = isc_buffer_current(opt);
6701         for (i = 0; i < nsid_len; i++) {
6702                 *p++ = hex[(nsid[0] >> 4) & 0xf];
6703                 *p++ = hex[nsid[0] & 0xf];
6704                 nsid++;
6705         }
6706         *p = '\0';
6707
6708         isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf,
6709                             sizeof(addrbuf));
6710         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
6711                       DNS_LOGMODULE_RESOLVER, level,
6712                       "received NSID '%s' from %s", buf, addrbuf);
6713
6714         /* Clean up */
6715         isc_mem_put(mctx, buf, buflen);
6716         return;
6717 }
6718
6719 static void
6720 log_packet(dns_message_t *message, int level, isc_mem_t *mctx) {
6721         isc_buffer_t buffer;
6722         char *buf = NULL;
6723         int len = 1024;
6724         isc_result_t result;
6725
6726         if (! isc_log_wouldlog(dns_lctx, level))
6727                 return;
6728
6729         /*
6730          * Note that these are multiline debug messages.  We want a newline
6731          * to appear in the log after each message.
6732          */
6733
6734         do {
6735                 buf = isc_mem_get(mctx, len);
6736                 if (buf == NULL)
6737                         break;
6738                 isc_buffer_init(&buffer, buf, len);
6739                 result = dns_message_totext(message, &dns_master_style_debug,
6740                                             0, &buffer);
6741                 if (result == ISC_R_NOSPACE) {
6742                         isc_mem_put(mctx, buf, len);
6743                         len += 1024;
6744                 } else if (result == ISC_R_SUCCESS)
6745                         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
6746                                       DNS_LOGMODULE_RESOLVER, level,
6747                                       "received packet:\n%.*s",
6748                                       (int)isc_buffer_usedlength(&buffer),
6749                                       buf);
6750         } while (result == ISC_R_NOSPACE);
6751
6752         if (buf != NULL)
6753                 isc_mem_put(mctx, buf, len);
6754 }
6755
6756 static isc_boolean_t
6757 iscname(fetchctx_t *fctx) {
6758         isc_result_t result;
6759
6760         result = dns_message_findname(fctx->rmessage, DNS_SECTION_ANSWER,
6761                                       &fctx->name, dns_rdatatype_cname, 0,
6762                                       NULL, NULL);
6763         return (result == ISC_R_SUCCESS ? ISC_TRUE : ISC_FALSE);
6764 }
6765
6766 static isc_boolean_t
6767 betterreferral(fetchctx_t *fctx) {
6768         isc_result_t result;
6769         dns_name_t *name;
6770         dns_rdataset_t *rdataset;
6771         dns_message_t *message = fctx->rmessage;
6772
6773         for (result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
6774              result == ISC_R_SUCCESS;
6775              result = dns_message_nextname(message, DNS_SECTION_AUTHORITY)) {
6776                 name = NULL;
6777                 dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
6778                 if (!isstrictsubdomain(name, &fctx->domain))
6779                         continue;
6780                 for (rdataset = ISC_LIST_HEAD(name->list);
6781                      rdataset != NULL;
6782                      rdataset = ISC_LIST_NEXT(rdataset, link))
6783                         if (rdataset->type == dns_rdatatype_ns)
6784                                 return (ISC_TRUE);
6785         }
6786         return (ISC_FALSE);
6787 }
6788
6789 static void
6790 process_opt(resquery_t *query, dns_rdataset_t *opt) {
6791         dns_rdata_t rdata;
6792         isc_buffer_t optbuf;
6793         isc_result_t result;
6794         isc_uint16_t optcode;
6795         isc_uint16_t optlen;
6796
6797         result = dns_rdataset_first(opt);
6798         if (result == ISC_R_SUCCESS) {
6799                 dns_rdata_init(&rdata);
6800                 dns_rdataset_current(opt, &rdata);
6801                 isc_buffer_init(&optbuf, rdata.data, rdata.length);
6802                 isc_buffer_add(&optbuf, rdata.length);
6803                 while (isc_buffer_remaininglength(&optbuf) >= 4) {
6804                         optcode = isc_buffer_getuint16(&optbuf);
6805                         optlen = isc_buffer_getuint16(&optbuf);
6806                         INSIST(optlen <= isc_buffer_remaininglength(&optbuf));
6807                         switch (optcode) {
6808                         case DNS_OPT_NSID:
6809                                 if (query->options & DNS_FETCHOPT_WANTNSID)
6810                                         log_nsid(&optbuf, optlen, query,
6811                                                  ISC_LOG_INFO,
6812                                                  query->fctx->res->mctx);
6813                                 isc_buffer_forward(&optbuf, optlen);
6814                                 break;
6815                         default:
6816                                 isc_buffer_forward(&optbuf, optlen);
6817                                 break;
6818                         }
6819                 }
6820                 INSIST(isc_buffer_remaininglength(&optbuf) == 0U);
6821         }
6822 }
6823
6824 static void
6825 resquery_response(isc_task_t *task, isc_event_t *event) {
6826         isc_result_t result = ISC_R_SUCCESS;
6827         resquery_t *query = event->ev_arg;
6828         dns_dispatchevent_t *devent = (dns_dispatchevent_t *)event;
6829         isc_boolean_t keep_trying, get_nameservers, resend;
6830         isc_boolean_t truncated;
6831         dns_message_t *message;
6832         dns_rdataset_t *opt;
6833         fetchctx_t *fctx;
6834         dns_name_t *fname;
6835         dns_fixedname_t foundname;
6836         isc_stdtime_t now;
6837         isc_time_t tnow, *finish;
6838         dns_adbaddrinfo_t *addrinfo;
6839         unsigned int options;
6840         unsigned int findoptions;
6841         isc_result_t broken_server;
6842         badnstype_t broken_type = badns_response;
6843         isc_boolean_t no_response;
6844
6845         REQUIRE(VALID_QUERY(query));
6846         fctx = query->fctx;
6847         options = query->options;
6848         REQUIRE(VALID_FCTX(fctx));
6849         REQUIRE(event->ev_type == DNS_EVENT_DISPATCH);
6850
6851         QTRACE("response");
6852
6853         if (isc_sockaddr_pf(&query->addrinfo->sockaddr) == PF_INET)
6854                 inc_stats(fctx->res, dns_resstatscounter_responsev4);
6855         else
6856                 inc_stats(fctx->res, dns_resstatscounter_responsev6);
6857
6858         (void)isc_timer_touch(fctx->timer);
6859
6860         keep_trying = ISC_FALSE;
6861         broken_server = ISC_R_SUCCESS;
6862         get_nameservers = ISC_FALSE;
6863         resend = ISC_FALSE;
6864         truncated = ISC_FALSE;
6865         finish = NULL;
6866         no_response = ISC_FALSE;
6867
6868         if (fctx->res->exiting) {
6869                 result = ISC_R_SHUTTINGDOWN;
6870                 goto done;
6871         }
6872
6873         fctx->timeouts = 0;
6874         fctx->timeout = ISC_FALSE;
6875         fctx->addrinfo = query->addrinfo;
6876
6877         /*
6878          * XXXRTH  We should really get the current time just once.  We
6879          *              need a routine to convert from an isc_time_t to an
6880          *              isc_stdtime_t.
6881          */
6882         TIME_NOW(&tnow);
6883         finish = &tnow;
6884         isc_stdtime_get(&now);
6885
6886         /*
6887          * Did the dispatcher have a problem?
6888          */
6889         if (devent->result != ISC_R_SUCCESS) {
6890                 if (devent->result == ISC_R_EOF &&
6891                     (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
6892                         /*
6893                          * The problem might be that they
6894                          * don't understand EDNS0.  Turn it
6895                          * off and try again.
6896                          */
6897                         options |= DNS_FETCHOPT_NOEDNS0;
6898                         resend = ISC_TRUE;
6899                         add_bad_edns(fctx, &query->addrinfo->sockaddr);
6900                 } else {
6901                         /*
6902                          * There's no hope for this query.
6903                          */
6904                         keep_trying = ISC_TRUE;
6905
6906                         /*
6907                          * If this is a network error on an exclusive query
6908                          * socket, mark the server as bad so that we won't try
6909                          * it for this fetch again.  Also adjust finish and
6910                          * no_response so that we penalize this address in SRTT
6911                          * adjustment later.
6912                          */
6913                         if (query->exclusivesocket &&
6914                             (devent->result == ISC_R_HOSTUNREACH ||
6915                              devent->result == ISC_R_NETUNREACH ||
6916                              devent->result == ISC_R_CONNREFUSED ||
6917                              devent->result == ISC_R_CANCELED)) {
6918                                     broken_server = devent->result;
6919                                     broken_type = badns_unreachable;
6920                                     finish = NULL;
6921                                     no_response = ISC_TRUE;
6922                         }
6923                 }
6924                 goto done;
6925         }
6926
6927         message = fctx->rmessage;
6928
6929         if (query->tsig != NULL) {
6930                 result = dns_message_setquerytsig(message, query->tsig);
6931                 if (result != ISC_R_SUCCESS)
6932                         goto done;
6933         }
6934
6935         if (query->tsigkey) {
6936                 result = dns_message_settsigkey(message, query->tsigkey);
6937                 if (result != ISC_R_SUCCESS)
6938                         goto done;
6939         }
6940
6941         dns_message_setclass(message, fctx->res->rdclass);
6942
6943         result = dns_message_parse(message, &devent->buffer, 0);
6944         if (result != ISC_R_SUCCESS) {
6945                 switch (result) {
6946                 case ISC_R_UNEXPECTEDEND:
6947                         if (!message->question_ok ||
6948                             (message->flags & DNS_MESSAGEFLAG_TC) == 0 ||
6949                             (options & DNS_FETCHOPT_TCP) != 0) {
6950                                 /*
6951                                  * Either the message ended prematurely,
6952                                  * and/or wasn't marked as being truncated,
6953                                  * and/or this is a response to a query we
6954                                  * sent over TCP.  In all of these cases,
6955                                  * something is wrong with the remote
6956                                  * server and we don't want to retry using
6957                                  * TCP.
6958                                  */
6959                                 if ((query->options & DNS_FETCHOPT_NOEDNS0)
6960                                     == 0) {
6961                                         /*
6962                                          * The problem might be that they
6963                                          * don't understand EDNS0.  Turn it
6964                                          * off and try again.
6965                                          */
6966                                         options |= DNS_FETCHOPT_NOEDNS0;
6967                                         resend = ISC_TRUE;
6968                                         add_bad_edns(fctx,
6969                                                     &query->addrinfo->sockaddr);
6970                                         inc_stats(fctx->res,
6971                                                  dns_resstatscounter_edns0fail);
6972                                 } else {
6973                                         broken_server = result;
6974                                         keep_trying = ISC_TRUE;
6975                                 }
6976                                 goto done;
6977                         }
6978                         /*
6979                          * We defer retrying via TCP for a bit so we can
6980                          * check out this message further.
6981                          */
6982                         truncated = ISC_TRUE;
6983                         break;
6984                 case DNS_R_FORMERR:
6985                         if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
6986                                 /*
6987                                  * The problem might be that they
6988                                  * don't understand EDNS0.  Turn it
6989                                  * off and try again.
6990                                  */
6991                                 options |= DNS_FETCHOPT_NOEDNS0;
6992                                 resend = ISC_TRUE;
6993                                 add_bad_edns(fctx, &query->addrinfo->sockaddr);
6994                                 inc_stats(fctx->res,
6995                                                  dns_resstatscounter_edns0fail);
6996                         } else {
6997                                 broken_server = DNS_R_UNEXPECTEDRCODE;
6998                                 keep_trying = ISC_TRUE;
6999                         }
7000                         goto done;
7001                 default:
7002                         /*
7003                          * Something bad has happened.
7004                          */
7005                         goto done;
7006                 }
7007         }
7008
7009
7010         /*
7011          * Log the incoming packet.
7012          */
7013         log_packet(message, ISC_LOG_DEBUG(10), fctx->res->mctx);
7014
7015         if (message->rdclass != fctx->res->rdclass) {
7016                 resend = ISC_TRUE;
7017                 FCTXTRACE("bad class");
7018                 goto done;
7019         }
7020
7021         /*
7022          * Process receive opt record.
7023          */
7024         opt = dns_message_getopt(message);
7025         if (opt != NULL)
7026                 process_opt(query, opt);
7027
7028         /*
7029          * If the message is signed, check the signature.  If not, this
7030          * returns success anyway.
7031          */
7032         result = dns_message_checksig(message, fctx->res->view);
7033         if (result != ISC_R_SUCCESS)
7034                 goto done;
7035
7036         /*
7037          * The dispatcher should ensure we only get responses with QR set.
7038          */
7039         INSIST((message->flags & DNS_MESSAGEFLAG_QR) != 0);
7040         /*
7041          * INSIST() that the message comes from the place we sent it to,
7042          * since the dispatch code should ensure this.
7043          *
7044          * INSIST() that the message id is correct (this should also be
7045          * ensured by the dispatch code).
7046          */
7047
7048         /*
7049          * We have an affirmative response to the query and we have
7050          * previously got a response from this server which indicated
7051          * EDNS may not be supported so we can now cache the lack of
7052          * EDNS support.
7053          */
7054         if (opt == NULL &&
7055             (message->rcode == dns_rcode_noerror ||
7056              message->rcode == dns_rcode_nxdomain ||
7057              message->rcode == dns_rcode_refused ||
7058              message->rcode == dns_rcode_yxdomain) &&
7059              bad_edns(fctx, &query->addrinfo->sockaddr)) {
7060                 char addrbuf[ISC_SOCKADDR_FORMATSIZE];
7061                 isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf,
7062                                     sizeof(addrbuf));
7063                 dns_adb_changeflags(fctx->adb, query->addrinfo,
7064                                     DNS_FETCHOPT_NOEDNS0,
7065                                     DNS_FETCHOPT_NOEDNS0);
7066         }
7067
7068         /*
7069          * Deal with truncated responses by retrying using TCP.
7070          */
7071         if ((message->flags & DNS_MESSAGEFLAG_TC) != 0)
7072                 truncated = ISC_TRUE;
7073
7074         if (truncated) {
7075                 inc_stats(fctx->res, dns_resstatscounter_truncated);
7076                 if ((options & DNS_FETCHOPT_TCP) != 0) {
7077                         broken_server = DNS_R_TRUNCATEDTCP;
7078                         keep_trying = ISC_TRUE;
7079                 } else {
7080                         options |= DNS_FETCHOPT_TCP;
7081                         resend = ISC_TRUE;
7082                 }
7083                 goto done;
7084         }
7085
7086         /*
7087          * Is it a query response?
7088          */
7089         if (message->opcode != dns_opcode_query) {
7090                 /* XXXRTH Log */
7091                 broken_server = DNS_R_UNEXPECTEDOPCODE;
7092                 keep_trying = ISC_TRUE;
7093                 goto done;
7094         }
7095
7096         /*
7097          * Update statistics about erroneous responses.
7098          */
7099         if (message->rcode != dns_rcode_noerror) {
7100                 switch (message->rcode) {
7101                 case dns_rcode_nxdomain:
7102                         inc_stats(fctx->res, dns_resstatscounter_nxdomain);
7103                         break;
7104                 case dns_rcode_servfail:
7105                         inc_stats(fctx->res, dns_resstatscounter_servfail);
7106                         break;
7107                 case dns_rcode_formerr:
7108                         inc_stats(fctx->res, dns_resstatscounter_formerr);
7109                         break;
7110                 default:
7111                         inc_stats(fctx->res, dns_resstatscounter_othererror);
7112                         break;
7113                 }
7114         }
7115
7116         /*
7117          * Is the remote server broken, or does it dislike us?
7118          */
7119         if (message->rcode != dns_rcode_noerror &&
7120             message->rcode != dns_rcode_nxdomain) {
7121                 if (((message->rcode == dns_rcode_formerr ||
7122                       message->rcode == dns_rcode_notimp) ||
7123                      (message->rcode == dns_rcode_servfail &&
7124                       dns_message_getopt(message) == NULL)) &&
7125                     (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
7126                         /*
7127                          * It's very likely they don't like EDNS0.
7128                          * If the response code is SERVFAIL, also check if the
7129                          * response contains an OPT RR and don't cache the
7130                          * failure since it can be returned for various other
7131                          * reasons.
7132                          *
7133                          * XXXRTH  We should check if the question
7134                          *              we're asking requires EDNS0, and
7135                          *              if so, we should bail out.
7136                          */
7137                         options |= DNS_FETCHOPT_NOEDNS0;
7138                         resend = ISC_TRUE;
7139                         /*
7140                          * Remember that they may not like EDNS0.
7141                          */
7142                         add_bad_edns(fctx, &query->addrinfo->sockaddr);
7143                         inc_stats(fctx->res, dns_resstatscounter_edns0fail);
7144                 } else if (message->rcode == dns_rcode_formerr) {
7145                         if (ISFORWARDER(query->addrinfo)) {
7146                                 /*
7147                                  * This forwarder doesn't understand us,
7148                                  * but other forwarders might.  Keep trying.
7149                                  */
7150                                 broken_server = DNS_R_REMOTEFORMERR;
7151                                 keep_trying = ISC_TRUE;
7152                         } else {
7153                                 /*
7154                                  * The server doesn't understand us.  Since
7155                                  * all servers for a zone need similar
7156                                  * capabilities, we assume that we will get
7157                                  * FORMERR from all servers, and thus we
7158                                  * cannot make any more progress with this
7159                                  * fetch.
7160                                  */
7161                                 log_formerr(fctx, "server sent FORMERR");
7162                                 result = DNS_R_FORMERR;
7163                         }
7164                 } else if (message->rcode == dns_rcode_yxdomain) {
7165                         /*
7166                          * DNAME mapping failed because the new name
7167                          * was too long.  There's no chance of success
7168                          * for this fetch.
7169                          */
7170                         result = DNS_R_YXDOMAIN;
7171                 } else if (message->rcode == dns_rcode_badvers) {
7172                         unsigned int flags, mask;
7173                         unsigned int version;
7174
7175                         resend = ISC_TRUE;
7176                         INSIST(opt != NULL);
7177                         version = (opt->ttl >> 16) & 0xff;
7178                         flags = (version << DNS_FETCHOPT_EDNSVERSIONSHIFT) |
7179                                 DNS_FETCHOPT_EDNSVERSIONSET;
7180                         mask = DNS_FETCHOPT_EDNSVERSIONMASK |
7181                                DNS_FETCHOPT_EDNSVERSIONSET;
7182                         switch (version) {
7183                         case 0:
7184                                 dns_adb_changeflags(fctx->adb, query->addrinfo,
7185                                                     flags, mask);
7186                                 break;
7187                         default:
7188                                 broken_server = DNS_R_BADVERS;
7189                                 keep_trying = ISC_TRUE;
7190                                 break;
7191                         }
7192                 } else {
7193                         /*
7194                          * XXXRTH log.
7195                          */
7196                         broken_server = DNS_R_UNEXPECTEDRCODE;
7197                         INSIST(broken_server != ISC_R_SUCCESS);
7198                         keep_trying = ISC_TRUE;
7199                 }
7200                 goto done;
7201         }
7202
7203         /*
7204          * Is the question the same as the one we asked?
7205          */
7206         result = same_question(fctx);
7207         if (result != ISC_R_SUCCESS) {
7208                 /* XXXRTH Log */
7209                 if (result == DNS_R_FORMERR)
7210                         keep_trying = ISC_TRUE;
7211                 goto done;
7212         }
7213
7214         /*
7215          * Is the server lame?
7216          */
7217         if (fctx->res->lame_ttl != 0 && !ISFORWARDER(query->addrinfo) &&
7218             is_lame(fctx)) {
7219                 inc_stats(fctx->res, dns_resstatscounter_lame);
7220                 log_lame(fctx, query->addrinfo);
7221                 result = dns_adb_marklame(fctx->adb, query->addrinfo,
7222                                           &fctx->name, fctx->type,
7223                                           now + fctx->res->lame_ttl);
7224                 if (result != ISC_R_SUCCESS)
7225                         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
7226                                       DNS_LOGMODULE_RESOLVER, ISC_LOG_ERROR,
7227                                       "could not mark server as lame: %s",
7228                                       isc_result_totext(result));
7229                 broken_server = DNS_R_LAME;
7230                 keep_trying = ISC_TRUE;
7231                 goto done;
7232         }
7233
7234         /*
7235          * Enforce delegations only zones like NET and COM.
7236          */
7237         if (!ISFORWARDER(query->addrinfo) &&
7238             dns_view_isdelegationonly(fctx->res->view, &fctx->domain) &&
7239             !dns_name_equal(&fctx->domain, &fctx->name) &&
7240             fix_mustbedelegationornxdomain(message, fctx)) {
7241                 char namebuf[DNS_NAME_FORMATSIZE];
7242                 char domainbuf[DNS_NAME_FORMATSIZE];
7243                 char addrbuf[ISC_SOCKADDR_FORMATSIZE];
7244                 char classbuf[64];
7245                 char typebuf[64];
7246
7247                 dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
7248                 dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
7249                 dns_rdatatype_format(fctx->type, typebuf, sizeof(typebuf));
7250                 dns_rdataclass_format(fctx->res->rdclass, classbuf,
7251                                       sizeof(classbuf));
7252                 isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf,
7253                                     sizeof(addrbuf));
7254
7255                 isc_log_write(dns_lctx, DNS_LOGCATEGORY_DELEGATION_ONLY,
7256                              DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
7257                              "enforced delegation-only for '%s' (%s/%s/%s) "
7258                              "from %s",
7259                              domainbuf, namebuf, typebuf, classbuf, addrbuf);
7260         }
7261
7262         if ((fctx->res->options & DNS_RESOLVER_CHECKNAMES) != 0)
7263                 checknames(message);
7264
7265         /*
7266          * Clear cache bits.
7267          */
7268         fctx->attributes &= ~(FCTX_ATTR_WANTNCACHE | FCTX_ATTR_WANTCACHE);
7269
7270         /*
7271          * Did we get any answers?
7272          */
7273         if (message->counts[DNS_SECTION_ANSWER] > 0 &&
7274             (message->rcode == dns_rcode_noerror ||
7275              message->rcode == dns_rcode_nxdomain)) {
7276                 /*
7277                  * [normal case]
7278                  * We've got answers.  If it has an authoritative answer or an
7279                  * answer from a forwarder, we're done.
7280                  */
7281                 if ((message->flags & DNS_MESSAGEFLAG_AA) != 0 ||
7282                     ISFORWARDER(query->addrinfo))
7283                         result = answer_response(fctx);
7284                 else if (iscname(fctx) &&
7285                          fctx->type != dns_rdatatype_any &&
7286                          fctx->type != dns_rdatatype_cname) {
7287                         /*
7288                          * A BIND8 server could return a non-authoritative
7289                          * answer when a CNAME is followed.  We should treat
7290                          * it as a valid answer.
7291                          */
7292                         result = answer_response(fctx);
7293                 } else if (fctx->type != dns_rdatatype_ns &&
7294                            !betterreferral(fctx)) {
7295                         /*
7296                          * Lame response !!!.
7297                          */
7298                         result = answer_response(fctx);
7299                 } else {
7300                         if (fctx->type == dns_rdatatype_ns) {
7301                                 /*
7302                                  * A BIND 8 server could incorrectly return a
7303                                  * non-authoritative answer to an NS query
7304                                  * instead of a referral. Since this answer
7305                                  * lacks the SIGs necessary to do DNSSEC
7306                                  * validation, we must invoke the following
7307                                  * special kludge to treat it as a referral.
7308                                  */
7309                                 result = noanswer_response(fctx, NULL,
7310                                                    LOOK_FOR_NS_IN_ANSWER);
7311                         } else {
7312                                 /*
7313                                  * Some other servers may still somehow include
7314                                  * an answer when it should return a referral
7315                                  * with an empty answer.  Check to see if we can
7316                                  * treat this as a referral by ignoring the
7317                                  * answer.  Further more, there may be an
7318                                  * implementation that moves A/AAAA glue records
7319                                  * to the answer section for that type of
7320                                  * delegation when the query is for that glue
7321                                  * record.  LOOK_FOR_GLUE_IN_ANSWER will handle
7322                                  * such a corner case.
7323                                  */
7324                                 result = noanswer_response(fctx, NULL,
7325                                                    LOOK_FOR_GLUE_IN_ANSWER);
7326                         }
7327                         if (result != DNS_R_DELEGATION) {
7328                                 /*
7329                                  * At this point, AA is not set, the response
7330                                  * is not a referral, and the server is not a
7331                                  * forwarder.  It is technically lame and it's
7332                                  * easier to treat it as such than to figure out
7333                                  * some more elaborate course of action.
7334                                  */
7335                                 broken_server = DNS_R_LAME;
7336                                 keep_trying = ISC_TRUE;
7337                                 goto done;
7338                         }
7339                         goto force_referral;
7340                 }
7341                 if (result != ISC_R_SUCCESS) {
7342                         if (result == DNS_R_FORMERR)
7343                                 keep_trying = ISC_TRUE;
7344                         goto done;
7345                 }
7346         } else if (message->counts[DNS_SECTION_AUTHORITY] > 0 ||
7347                    message->rcode == dns_rcode_noerror ||
7348                    message->rcode == dns_rcode_nxdomain) {
7349                 /*
7350                  * NXDOMAIN, NXRDATASET, or referral.
7351                  */
7352                 result = noanswer_response(fctx, NULL, 0);
7353                 switch (result) {
7354                 case ISC_R_SUCCESS:
7355                 case DNS_R_CHASEDSSERVERS:
7356                         break;
7357                 case DNS_R_DELEGATION:
7358  force_referral:
7359                         /*
7360                          * We don't have the answer, but we know a better
7361                          * place to look.
7362                          */
7363                         get_nameservers = ISC_TRUE;
7364                         keep_trying = ISC_TRUE;
7365                         /*
7366                          * We have a new set of name servers, and it
7367                          * has not experienced any restarts yet.
7368                          */
7369                         fctx->restarts = 0;
7370
7371                         /*
7372                          * Update local statistics counters collected for each
7373                          * new zone.
7374                          */
7375                         fctx->referrals++;
7376                         fctx->querysent = 0;
7377                         fctx->lamecount = 0;
7378                         fctx->neterr = 0;
7379                         fctx->badresp = 0;
7380                         fctx->adberr = 0;
7381
7382                         result = ISC_R_SUCCESS;
7383                         break;
7384                 default:
7385                         /*
7386                          * Something has gone wrong.
7387                          */
7388                         if (result == DNS_R_FORMERR)
7389                                 keep_trying = ISC_TRUE;
7390                         goto done;
7391                 }
7392         } else {
7393                 /*
7394                  * The server is insane.
7395                  */
7396                 /* XXXRTH Log */
7397                 broken_server = DNS_R_UNEXPECTEDRCODE;
7398                 keep_trying = ISC_TRUE;
7399                 goto done;
7400         }
7401
7402         /*
7403          * Follow additional section data chains.
7404          */
7405         chase_additional(fctx);
7406
7407         /*
7408          * Cache the cacheable parts of the message.  This may also cause
7409          * work to be queued to the DNSSEC validator.
7410          */
7411         if (WANTCACHE(fctx)) {
7412                 result = cache_message(fctx, query->addrinfo, now);
7413                 if (result != ISC_R_SUCCESS)
7414                         goto done;
7415         }
7416
7417         /*
7418          * Ncache the negatively cacheable parts of the message.  This may
7419          * also cause work to be queued to the DNSSEC validator.
7420          */
7421         if (WANTNCACHE(fctx)) {
7422                 dns_rdatatype_t covers;
7423                 if (message->rcode == dns_rcode_nxdomain)
7424                         covers = dns_rdatatype_any;
7425                 else
7426                         covers = fctx->type;
7427
7428                 /*
7429                  * Cache any negative cache entries in the message.
7430                  */
7431                 result = ncache_message(fctx, query->addrinfo, covers, now);
7432         }
7433
7434  done:
7435         /*
7436          * Remember the query's addrinfo, in case we need to mark the
7437          * server as broken.
7438          */
7439         addrinfo = query->addrinfo;
7440
7441         /*
7442          * Cancel the query.
7443          *
7444          * XXXRTH  Don't cancel the query if waiting for validation?
7445          */
7446         fctx_cancelquery(&query, &devent, finish, no_response);
7447
7448         if (keep_trying) {
7449                 if (result == DNS_R_FORMERR)
7450                         broken_server = DNS_R_FORMERR;
7451                 if (broken_server != ISC_R_SUCCESS) {
7452                         /*
7453                          * Add this server to the list of bad servers for
7454                          * this fctx.
7455                          */
7456                         add_bad(fctx, addrinfo, broken_server, broken_type);
7457                 }
7458
7459                 if (get_nameservers) {
7460                         dns_name_t *name;
7461                         dns_fixedname_init(&foundname);
7462                         fname = dns_fixedname_name(&foundname);
7463                         if (result != ISC_R_SUCCESS) {
7464                                 fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
7465                                 return;
7466                         }
7467                         findoptions = 0;
7468                         if (dns_rdatatype_atparent(fctx->type))
7469                                 findoptions |= DNS_DBFIND_NOEXACT;
7470                         if ((options & DNS_FETCHOPT_UNSHARED) == 0)
7471                                 name = &fctx->name;
7472                         else
7473                                 name = &fctx->domain;
7474                         result = dns_view_findzonecut(fctx->res->view,
7475                                                       name, fname,
7476                                                       now, findoptions,
7477                                                       ISC_TRUE,
7478                                                       &fctx->nameservers,
7479                                                       NULL);
7480                         if (result != ISC_R_SUCCESS) {
7481                                 FCTXTRACE("couldn't find a zonecut");
7482                                 fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
7483                                 return;
7484                         }
7485                         if (!dns_name_issubdomain(fname, &fctx->domain)) {
7486                                 /*
7487                                  * The best nameservers are now above our
7488                                  * QDOMAIN.
7489                                  */
7490                                 FCTXTRACE("nameservers now above QDOMAIN");
7491                                 fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
7492                                 return;
7493                         }
7494                         dns_name_free(&fctx->domain, fctx->mctx);
7495                         dns_name_init(&fctx->domain, NULL);
7496                         result = dns_name_dup(fname, fctx->mctx, &fctx->domain);
7497                         if (result != ISC_R_SUCCESS) {
7498                                 fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
7499                                 return;
7500                         }
7501                         fctx->ns_ttl = fctx->nameservers.ttl;
7502                         fctx->ns_ttl_ok = ISC_TRUE;
7503                         fctx_cancelqueries(fctx, ISC_TRUE);
7504                         fctx_cleanupfinds(fctx);
7505                         fctx_cleanupaltfinds(fctx);
7506                         fctx_cleanupforwaddrs(fctx);
7507                         fctx_cleanupaltaddrs(fctx);
7508                 }
7509                 /*
7510                  * Try again.
7511                  */
7512                 fctx_try(fctx, !get_nameservers, ISC_FALSE);
7513         } else if (resend) {
7514                 /*
7515                  * Resend (probably with changed options).
7516                  */
7517                 FCTXTRACE("resend");
7518                 inc_stats(fctx->res, dns_resstatscounter_retry);
7519                 result = fctx_query(fctx, addrinfo, options);
7520                 if (result != ISC_R_SUCCESS)
7521                         fctx_done(fctx, result, __LINE__);
7522         } else if (result == ISC_R_SUCCESS && !HAVE_ANSWER(fctx)) {
7523                 /*
7524                  * All has gone well so far, but we are waiting for the
7525                  * DNSSEC validator to validate the answer.
7526                  */
7527                 FCTXTRACE("wait for validator");
7528                 fctx_cancelqueries(fctx, ISC_TRUE);
7529                 /*
7530                  * We must not retransmit while the validator is working;
7531                  * it has references to the current rmessage.
7532                  */
7533                 result = fctx_stopidletimer(fctx);
7534                 if (result != ISC_R_SUCCESS)
7535                         fctx_done(fctx, result, __LINE__);
7536         } else if (result == DNS_R_CHASEDSSERVERS) {
7537                 unsigned int n;
7538                 add_bad(fctx, addrinfo, result, broken_type);
7539                 fctx_cancelqueries(fctx, ISC_TRUE);
7540                 fctx_cleanupfinds(fctx);
7541                 fctx_cleanupforwaddrs(fctx);
7542
7543                 n = dns_name_countlabels(&fctx->name);
7544                 dns_name_getlabelsequence(&fctx->name, 1, n - 1, &fctx->nsname);
7545
7546                 FCTXTRACE("suspending DS lookup to find parent's NS records");
7547
7548                 result = dns_resolver_createfetch(fctx->res, &fctx->nsname,
7549                                                   dns_rdatatype_ns,
7550                                                   NULL, NULL, NULL, 0, task,
7551                                                   resume_dslookup, fctx,
7552                                                   &fctx->nsrrset, NULL,
7553                                                   &fctx->nsfetch);
7554                 if (result != ISC_R_SUCCESS)
7555                         fctx_done(fctx, result, __LINE__);
7556                 else {
7557                         LOCK(&fctx->res->buckets[fctx->bucketnum].lock);
7558                         fctx->references++;
7559                         UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
7560                         result = fctx_stopidletimer(fctx);
7561                         if (result != ISC_R_SUCCESS)
7562                                 fctx_done(fctx, result, __LINE__);
7563                 }
7564         } else {
7565                 /*
7566                  * We're done.
7567                  */
7568                 fctx_done(fctx, result, __LINE__);
7569         }
7570 }
7571
7572
7573 /***
7574  *** Resolver Methods
7575  ***/
7576 static void
7577 destroy_badcache(dns_resolver_t *res) {
7578         dns_badcache_t *bad, *next;
7579         unsigned int i;
7580
7581         if (res->badcache != NULL) {
7582                 for (i = 0; i < res->badhash; i++)
7583                         for (bad = res->badcache[i]; bad != NULL;
7584                              bad = next) {
7585                                 next = bad->next;
7586                                 isc_mem_put(res->mctx, bad, sizeof(*bad) +
7587                                             bad->name.length);
7588                                 res->badcount--;
7589                         }
7590                 isc_mem_put(res->mctx, res->badcache,
7591                             sizeof(*res->badcache) * res->badhash);
7592                 res->badcache = NULL;
7593                 res->badhash = 0;
7594                 INSIST(res->badcount == 0);
7595         }
7596 }
7597
7598 static void
7599 destroy(dns_resolver_t *res) {
7600         unsigned int i;
7601         alternate_t *a;
7602
7603         REQUIRE(res->references == 0);
7604         REQUIRE(!res->priming);
7605         REQUIRE(res->primefetch == NULL);
7606
7607         RTRACE("destroy");
7608
7609         INSIST(res->nfctx == 0);
7610
7611         DESTROYLOCK(&res->primelock);
7612         DESTROYLOCK(&res->nlock);
7613         DESTROYLOCK(&res->lock);
7614         for (i = 0; i < res->nbuckets; i++) {
7615                 INSIST(ISC_LIST_EMPTY(res->buckets[i].fctxs));
7616                 isc_task_shutdown(res->buckets[i].task);
7617                 isc_task_detach(&res->buckets[i].task);
7618                 DESTROYLOCK(&res->buckets[i].lock);
7619                 isc_mem_detach(&res->buckets[i].mctx);
7620         }
7621         isc_mem_put(res->mctx, res->buckets,
7622                     res->nbuckets * sizeof(fctxbucket_t));
7623         if (res->dispatches4 != NULL)
7624                 dns_dispatchset_destroy(&res->dispatches4);
7625         if (res->dispatches6 != NULL)
7626                 dns_dispatchset_destroy(&res->dispatches6);
7627         while ((a = ISC_LIST_HEAD(res->alternates)) != NULL) {
7628                 ISC_LIST_UNLINK(res->alternates, a, link);
7629                 if (!a->isaddress)
7630                         dns_name_free(&a->_u._n.name, res->mctx);
7631                 isc_mem_put(res->mctx, a, sizeof(*a));
7632         }
7633         dns_resolver_reset_algorithms(res);
7634         destroy_badcache(res);
7635         dns_resolver_resetmustbesecure(res);
7636 #if USE_ALGLOCK
7637         isc_rwlock_destroy(&res->alglock);
7638 #endif
7639 #if USE_MBSLOCK
7640         isc_rwlock_destroy(&res->mbslock);
7641 #endif
7642         isc_timer_detach(&res->spillattimer);
7643         res->magic = 0;
7644         isc_mem_put(res->mctx, res, sizeof(*res));
7645 }
7646
7647 static void
7648 send_shutdown_events(dns_resolver_t *res) {
7649         isc_event_t *event, *next_event;
7650         isc_task_t *etask;
7651
7652         /*
7653          * Caller must be holding the resolver lock.
7654          */
7655
7656         for (event = ISC_LIST_HEAD(res->whenshutdown);
7657              event != NULL;
7658              event = next_event) {
7659                 next_event = ISC_LIST_NEXT(event, ev_link);
7660                 ISC_LIST_UNLINK(res->whenshutdown, event, ev_link);
7661                 etask = event->ev_sender;
7662                 event->ev_sender = res;
7663                 isc_task_sendanddetach(&etask, &event);
7664         }
7665 }
7666
7667 static void
7668 empty_bucket(dns_resolver_t *res) {
7669         RTRACE("empty_bucket");
7670
7671         LOCK(&res->lock);
7672
7673         INSIST(res->activebuckets > 0);
7674         res->activebuckets--;
7675         if (res->activebuckets == 0)
7676                 send_shutdown_events(res);
7677
7678         UNLOCK(&res->lock);
7679 }
7680
7681 static void
7682 spillattimer_countdown(isc_task_t *task, isc_event_t *event) {
7683         dns_resolver_t *res = event->ev_arg;
7684         isc_result_t result;
7685         unsigned int count;
7686         isc_boolean_t logit = ISC_FALSE;
7687
7688         REQUIRE(VALID_RESOLVER(res));
7689
7690         UNUSED(task);
7691
7692         LOCK(&res->lock);
7693         INSIST(!res->exiting);
7694         if (res->spillat > res->spillatmin) {
7695                 res->spillat--;
7696                 logit = ISC_TRUE;
7697         }
7698         if (res->spillat <= res->spillatmin) {
7699                 result = isc_timer_reset(res->spillattimer,
7700                                          isc_timertype_inactive, NULL,
7701                                          NULL, ISC_TRUE);
7702                 RUNTIME_CHECK(result == ISC_R_SUCCESS);
7703         }
7704         count = res->spillat;
7705         UNLOCK(&res->lock);
7706         if (logit)
7707                 isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
7708                               DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
7709                               "clients-per-query decreased to %u", count);
7710
7711         isc_event_free(&event);
7712 }
7713
7714 isc_result_t
7715 dns_resolver_create(dns_view_t *view,
7716                     isc_taskmgr_t *taskmgr,
7717                     unsigned int ntasks, unsigned int ndisp,
7718                     isc_socketmgr_t *socketmgr,
7719                     isc_timermgr_t *timermgr,
7720                     unsigned int options,
7721                     dns_dispatchmgr_t *dispatchmgr,
7722                     dns_dispatch_t *dispatchv4,
7723                     dns_dispatch_t *dispatchv6,
7724                     dns_resolver_t **resp)
7725 {
7726         dns_resolver_t *res;
7727         isc_result_t result = ISC_R_SUCCESS;
7728         unsigned int i, buckets_created = 0;
7729         isc_task_t *task = NULL;
7730         char name[16];
7731         unsigned dispattr;
7732
7733         /*
7734          * Create a resolver.
7735          */
7736
7737         REQUIRE(DNS_VIEW_VALID(view));
7738         REQUIRE(ntasks > 0);
7739         REQUIRE(ndisp > 0);
7740         REQUIRE(resp != NULL && *resp == NULL);
7741         REQUIRE(dispatchmgr != NULL);
7742         REQUIRE(dispatchv4 != NULL || dispatchv6 != NULL);
7743
7744         res = isc_mem_get(view->mctx, sizeof(*res));
7745         if (res == NULL)
7746                 return (ISC_R_NOMEMORY);
7747         RTRACE("create");
7748         res->mctx = view->mctx;
7749         res->rdclass = view->rdclass;
7750         res->socketmgr = socketmgr;
7751         res->timermgr = timermgr;
7752         res->taskmgr = taskmgr;
7753         res->dispatchmgr = dispatchmgr;
7754         res->view = view;
7755         res->options = options;
7756         res->lame_ttl = 0;
7757         ISC_LIST_INIT(res->alternates);
7758         res->udpsize = RECV_BUFFER_SIZE;
7759         res->algorithms = NULL;
7760         res->badcache = NULL;
7761         res->badcount = 0;
7762         res->badhash = 0;
7763         res->badsweep = 0;
7764         res->mustbesecure = NULL;
7765         res->spillatmin = res->spillat = 10;
7766         res->spillatmax = 100;
7767         res->spillattimer = NULL;
7768         res->zero_no_soa_ttl = ISC_FALSE;
7769         res->query_timeout = DEFAULT_QUERY_TIMEOUT;
7770         res->maxdepth = DEFAULT_RECURSION_DEPTH;
7771         res->nbuckets = ntasks;
7772         res->activebuckets = ntasks;
7773         res->buckets = isc_mem_get(view->mctx,
7774                                    ntasks * sizeof(fctxbucket_t));
7775         if (res->buckets == NULL) {
7776                 result = ISC_R_NOMEMORY;
7777                 goto cleanup_res;
7778         }
7779         for (i = 0; i < ntasks; i++) {
7780                 result = isc_mutex_init(&res->buckets[i].lock);
7781                 if (result != ISC_R_SUCCESS)
7782                         goto cleanup_buckets;
7783                 res->buckets[i].task = NULL;
7784                 result = isc_task_create(taskmgr, 0, &res->buckets[i].task);
7785                 if (result != ISC_R_SUCCESS) {
7786                         DESTROYLOCK(&res->buckets[i].lock);
7787                         goto cleanup_buckets;
7788                 }
7789                 res->buckets[i].mctx = NULL;
7790                 snprintf(name, sizeof(name), "res%u", i);
7791 #ifdef ISC_PLATFORM_USETHREADS
7792                 /*
7793                  * Use a separate memory context for each bucket to reduce
7794                  * contention among multiple threads.  Do this only when
7795                  * enabling threads because it will be require more memory.
7796                  */
7797                 result = isc_mem_create(0, 0, &res->buckets[i].mctx);
7798                 if (result != ISC_R_SUCCESS) {
7799                         isc_task_detach(&res->buckets[i].task);
7800                         DESTROYLOCK(&res->buckets[i].lock);
7801                         goto cleanup_buckets;
7802                 }
7803                 isc_mem_setname(res->buckets[i].mctx, name, NULL);
7804 #else
7805                 isc_mem_attach(view->mctx, &res->buckets[i].mctx);
7806 #endif
7807                 isc_task_setname(res->buckets[i].task, name, res);
7808                 ISC_LIST_INIT(res->buckets[i].fctxs);
7809                 res->buckets[i].exiting = ISC_FALSE;
7810                 buckets_created++;
7811         }
7812
7813         res->dispatches4 = NULL;
7814         if (dispatchv4 != NULL) {
7815                 dns_dispatchset_create(view->mctx, socketmgr, taskmgr,
7816                                        dispatchv4, &res->dispatches4, ndisp);
7817                 dispattr = dns_dispatch_getattributes(dispatchv4);
7818                 res->exclusivev4 =
7819                         ISC_TF((dispattr & DNS_DISPATCHATTR_EXCLUSIVE) != 0);
7820         }
7821
7822         res->dispatches6 = NULL;
7823         if (dispatchv6 != NULL) {
7824                 dns_dispatchset_create(view->mctx, socketmgr, taskmgr,
7825                                        dispatchv6, &res->dispatches6, ndisp);
7826                 dispattr = dns_dispatch_getattributes(dispatchv6);
7827                 res->exclusivev6 =
7828                         ISC_TF((dispattr & DNS_DISPATCHATTR_EXCLUSIVE) != 0);
7829         }
7830
7831         res->references = 1;
7832         res->exiting = ISC_FALSE;
7833         res->frozen = ISC_FALSE;
7834         ISC_LIST_INIT(res->whenshutdown);
7835         res->priming = ISC_FALSE;
7836         res->primefetch = NULL;
7837         res->nfctx = 0;
7838
7839         result = isc_mutex_init(&res->lock);
7840         if (result != ISC_R_SUCCESS)
7841                 goto cleanup_dispatches;
7842
7843         result = isc_mutex_init(&res->nlock);
7844         if (result != ISC_R_SUCCESS)
7845                 goto cleanup_lock;
7846
7847         result = isc_mutex_init(&res->primelock);
7848         if (result != ISC_R_SUCCESS)
7849                 goto cleanup_nlock;
7850
7851         task = NULL;
7852         result = isc_task_create(taskmgr, 0, &task);
7853         if (result != ISC_R_SUCCESS)
7854                 goto cleanup_primelock;
7855
7856         result = isc_timer_create(timermgr, isc_timertype_inactive, NULL, NULL,
7857                                   task, spillattimer_countdown, res,
7858                                   &res->spillattimer);
7859         isc_task_detach(&task);
7860         if (result != ISC_R_SUCCESS)
7861                 goto cleanup_primelock;
7862
7863 #if USE_ALGLOCK
7864         result = isc_rwlock_init(&res->alglock, 0, 0);
7865         if (result != ISC_R_SUCCESS)
7866                 goto cleanup_spillattimer;
7867 #endif
7868 #if USE_MBSLOCK
7869         result = isc_rwlock_init(&res->mbslock, 0, 0);
7870         if (result != ISC_R_SUCCESS)
7871                 goto cleanup_alglock;
7872 #endif
7873
7874         res->magic = RES_MAGIC;
7875
7876         *resp = res;
7877
7878         return (ISC_R_SUCCESS);
7879
7880 #if USE_MBSLOCK
7881  cleanup_alglock:
7882 #if USE_ALGLOCK
7883         isc_rwlock_destroy(&res->alglock);
7884 #endif
7885 #endif
7886 #if USE_ALGLOCK || USE_MBSLOCK
7887  cleanup_spillattimer:
7888         isc_timer_detach(&res->spillattimer);
7889 #endif
7890
7891  cleanup_primelock:
7892         DESTROYLOCK(&res->primelock);
7893
7894  cleanup_nlock:
7895         DESTROYLOCK(&res->nlock);
7896
7897  cleanup_lock:
7898         DESTROYLOCK(&res->lock);
7899
7900  cleanup_dispatches:
7901         if (res->dispatches6 != NULL)
7902                 dns_dispatchset_destroy(&res->dispatches6);
7903         if (res->dispatches4 != NULL)
7904                 dns_dispatchset_destroy(&res->dispatches4);
7905
7906  cleanup_buckets:
7907         for (i = 0; i < buckets_created; i++) {
7908                 isc_mem_detach(&res->buckets[i].mctx);
7909                 DESTROYLOCK(&res->buckets[i].lock);
7910                 isc_task_shutdown(res->buckets[i].task);
7911                 isc_task_detach(&res->buckets[i].task);
7912         }
7913         isc_mem_put(view->mctx, res->buckets,
7914                     res->nbuckets * sizeof(fctxbucket_t));
7915
7916  cleanup_res:
7917         isc_mem_put(view->mctx, res, sizeof(*res));
7918
7919         return (result);
7920 }
7921
7922 #ifdef BIND9
7923 static void
7924 prime_done(isc_task_t *task, isc_event_t *event) {
7925         dns_resolver_t *res;
7926         dns_fetchevent_t *fevent;
7927         dns_fetch_t *fetch;
7928         dns_db_t *db = NULL;
7929
7930         REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE);
7931         fevent = (dns_fetchevent_t *)event;
7932         res = event->ev_arg;
7933         REQUIRE(VALID_RESOLVER(res));
7934
7935         UNUSED(task);
7936
7937         LOCK(&res->lock);
7938
7939         INSIST(res->priming);
7940         res->priming = ISC_FALSE;
7941         LOCK(&res->primelock);
7942         fetch = res->primefetch;
7943         res->primefetch = NULL;
7944         UNLOCK(&res->primelock);
7945
7946         UNLOCK(&res->lock);
7947
7948         if (fevent->result == ISC_R_SUCCESS &&
7949             res->view->cache != NULL && res->view->hints != NULL) {
7950                 dns_cache_attachdb(res->view->cache, &db);
7951                 dns_root_checkhints(res->view, res->view->hints, db);
7952                 dns_db_detach(&db);
7953         }
7954
7955         if (fevent->node != NULL)
7956                 dns_db_detachnode(fevent->db, &fevent->node);
7957         if (fevent->db != NULL)
7958                 dns_db_detach(&fevent->db);
7959         if (dns_rdataset_isassociated(fevent->rdataset))
7960                 dns_rdataset_disassociate(fevent->rdataset);
7961         INSIST(fevent->sigrdataset == NULL);
7962
7963         isc_mem_put(res->mctx, fevent->rdataset, sizeof(*fevent->rdataset));
7964
7965         isc_event_free(&event);
7966         dns_resolver_destroyfetch(&fetch);
7967 }
7968
7969 void
7970 dns_resolver_prime(dns_resolver_t *res) {
7971         isc_boolean_t want_priming = ISC_FALSE;
7972         dns_rdataset_t *rdataset;
7973         isc_result_t result;
7974
7975         REQUIRE(VALID_RESOLVER(res));
7976         REQUIRE(res->frozen);
7977
7978         RTRACE("dns_resolver_prime");
7979
7980         LOCK(&res->lock);
7981
7982         if (!res->exiting && !res->priming) {
7983                 INSIST(res->primefetch == NULL);
7984                 res->priming = ISC_TRUE;
7985                 want_priming = ISC_TRUE;
7986         }
7987
7988         UNLOCK(&res->lock);
7989
7990         if (want_priming) {
7991                 /*
7992                  * To avoid any possible recursive locking problems, we
7993                  * start the priming fetch like any other fetch, and holding
7994                  * no resolver locks.  No one else will try to start it
7995                  * because we're the ones who set res->priming to true.
7996                  * Any other callers of dns_resolver_prime() while we're
7997                  * running will see that res->priming is already true and
7998                  * do nothing.
7999                  */
8000                 RTRACE("priming");
8001                 rdataset = isc_mem_get(res->mctx, sizeof(*rdataset));
8002                 if (rdataset == NULL) {
8003                         LOCK(&res->lock);
8004                         INSIST(res->priming);
8005                         INSIST(res->primefetch == NULL);
8006                         res->priming = ISC_FALSE;
8007                         UNLOCK(&res->lock);
8008                         return;
8009                 }
8010                 dns_rdataset_init(rdataset);
8011                 LOCK(&res->primelock);
8012                 result = dns_resolver_createfetch(res, dns_rootname,
8013                                                   dns_rdatatype_ns,
8014                                                   NULL, NULL, NULL, 0,
8015                                                   res->buckets[0].task,
8016                                                   prime_done,
8017                                                   res, rdataset, NULL,
8018                                                   &res->primefetch);
8019                 UNLOCK(&res->primelock);
8020                 if (result != ISC_R_SUCCESS) {
8021                         LOCK(&res->lock);
8022                         INSIST(res->priming);
8023                         res->priming = ISC_FALSE;
8024                         UNLOCK(&res->lock);
8025                 }
8026         }
8027 }
8028 #endif /* BIND9 */
8029
8030 void
8031 dns_resolver_freeze(dns_resolver_t *res) {
8032         /*
8033          * Freeze resolver.
8034          */
8035
8036         REQUIRE(VALID_RESOLVER(res));
8037
8038         res->frozen = ISC_TRUE;
8039 }
8040
8041 void
8042 dns_resolver_attach(dns_resolver_t *source, dns_resolver_t **targetp) {
8043         REQUIRE(VALID_RESOLVER(source));
8044         REQUIRE(targetp != NULL && *targetp == NULL);
8045
8046         RRTRACE(source, "attach");
8047         LOCK(&source->lock);
8048         REQUIRE(!source->exiting);
8049
8050         INSIST(source->references > 0);
8051         source->references++;
8052         INSIST(source->references != 0);
8053         UNLOCK(&source->lock);
8054
8055         *targetp = source;
8056 }
8057
8058 void
8059 dns_resolver_whenshutdown(dns_resolver_t *res, isc_task_t *task,
8060                           isc_event_t **eventp)
8061 {
8062         isc_task_t *clone;
8063         isc_event_t *event;
8064
8065         REQUIRE(VALID_RESOLVER(res));
8066         REQUIRE(eventp != NULL);
8067
8068         event = *eventp;
8069         *eventp = NULL;
8070
8071         LOCK(&res->lock);
8072
8073         if (res->exiting && res->activebuckets == 0) {
8074                 /*
8075                  * We're already shutdown.  Send the event.
8076                  */
8077                 event->ev_sender = res;
8078                 isc_task_send(task, &event);
8079         } else {
8080                 clone = NULL;
8081                 isc_task_attach(task, &clone);
8082                 event->ev_sender = clone;
8083                 ISC_LIST_APPEND(res->whenshutdown, event, ev_link);
8084         }
8085
8086         UNLOCK(&res->lock);
8087 }
8088
8089 void
8090 dns_resolver_shutdown(dns_resolver_t *res) {
8091         unsigned int i;
8092         fetchctx_t *fctx;
8093         isc_result_t result;
8094
8095         REQUIRE(VALID_RESOLVER(res));
8096
8097         RTRACE("shutdown");
8098
8099         LOCK(&res->lock);
8100
8101         if (!res->exiting) {
8102                 RTRACE("exiting");
8103                 res->exiting = ISC_TRUE;
8104
8105                 for (i = 0; i < res->nbuckets; i++) {
8106                         LOCK(&res->buckets[i].lock);
8107                         for (fctx = ISC_LIST_HEAD(res->buckets[i].fctxs);
8108                              fctx != NULL;
8109                              fctx = ISC_LIST_NEXT(fctx, link))
8110                                 fctx_shutdown(fctx);
8111                         if (res->dispatches4 != NULL && !res->exclusivev4) {
8112                                 dns_dispatchset_cancelall(res->dispatches4,
8113                                                           res->buckets[i].task);
8114                         }
8115                         if (res->dispatches6 != NULL && !res->exclusivev6) {
8116                                 dns_dispatchset_cancelall(res->dispatches6,
8117                                                           res->buckets[i].task);
8118                         }
8119                         res->buckets[i].exiting = ISC_TRUE;
8120                         if (ISC_LIST_EMPTY(res->buckets[i].fctxs)) {
8121                                 INSIST(res->activebuckets > 0);
8122                                 res->activebuckets--;
8123                         }
8124                         UNLOCK(&res->buckets[i].lock);
8125                 }
8126                 if (res->activebuckets == 0)
8127                         send_shutdown_events(res);
8128                 result = isc_timer_reset(res->spillattimer,
8129                                          isc_timertype_inactive, NULL,
8130                                          NULL, ISC_TRUE);
8131                 RUNTIME_CHECK(result == ISC_R_SUCCESS);
8132         }
8133
8134         UNLOCK(&res->lock);
8135 }
8136
8137 void
8138 dns_resolver_detach(dns_resolver_t **resp) {
8139         dns_resolver_t *res;
8140         isc_boolean_t need_destroy = ISC_FALSE;
8141
8142         REQUIRE(resp != NULL);
8143         res = *resp;
8144         REQUIRE(VALID_RESOLVER(res));
8145
8146         RTRACE("detach");
8147
8148         LOCK(&res->lock);
8149
8150         INSIST(res->references > 0);
8151         res->references--;
8152         if (res->references == 0) {
8153                 INSIST(res->exiting && res->activebuckets == 0);
8154                 need_destroy = ISC_TRUE;
8155         }
8156
8157         UNLOCK(&res->lock);
8158
8159         if (need_destroy)
8160                 destroy(res);
8161
8162         *resp = NULL;
8163 }
8164
8165 static inline isc_boolean_t
8166 fctx_match(fetchctx_t *fctx, dns_name_t *name, dns_rdatatype_t type,
8167            unsigned int options)
8168 {
8169         /*
8170          * Don't match fetch contexts that are shutting down.
8171          */
8172         if (fctx->cloned || fctx->state == fetchstate_done ||
8173             ISC_LIST_EMPTY(fctx->events))
8174                 return (ISC_FALSE);
8175
8176         if (fctx->type != type || fctx->options != options)
8177                 return (ISC_FALSE);
8178         return (dns_name_equal(&fctx->name, name));
8179 }
8180
8181 static inline void
8182 log_fetch(dns_name_t *name, dns_rdatatype_t type) {
8183         char namebuf[DNS_NAME_FORMATSIZE];
8184         char typebuf[DNS_RDATATYPE_FORMATSIZE];
8185         int level = ISC_LOG_DEBUG(1);
8186
8187         if (! isc_log_wouldlog(dns_lctx, level))
8188                 return;
8189
8190         dns_name_format(name, namebuf, sizeof(namebuf));
8191         dns_rdatatype_format(type, typebuf, sizeof(typebuf));
8192
8193         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
8194                       DNS_LOGMODULE_RESOLVER, level,
8195                       "createfetch: %s %s", namebuf, typebuf);
8196 }
8197
8198 isc_result_t
8199 dns_resolver_createfetch(dns_resolver_t *res, dns_name_t *name,
8200                          dns_rdatatype_t type,
8201                          dns_name_t *domain, dns_rdataset_t *nameservers,
8202                          dns_forwarders_t *forwarders,
8203                          unsigned int options, isc_task_t *task,
8204                          isc_taskaction_t action, void *arg,
8205                          dns_rdataset_t *rdataset,
8206                          dns_rdataset_t *sigrdataset,
8207                          dns_fetch_t **fetchp)
8208 {
8209         return (dns_resolver_createfetch3(res, name, type, domain,
8210                                           nameservers, forwarders, NULL, 0,
8211                                           options, 0, task, action, arg,
8212                                           rdataset, sigrdataset, fetchp));
8213 }
8214
8215 isc_result_t
8216 dns_resolver_createfetch2(dns_resolver_t *res, dns_name_t *name,
8217                           dns_rdatatype_t type,
8218                           dns_name_t *domain, dns_rdataset_t *nameservers,
8219                           dns_forwarders_t *forwarders,
8220                           isc_sockaddr_t *client, dns_messageid_t id,
8221                           unsigned int options, isc_task_t *task,
8222                           isc_taskaction_t action, void *arg,
8223                           dns_rdataset_t *rdataset,
8224                           dns_rdataset_t *sigrdataset,
8225                           dns_fetch_t **fetchp)
8226 {
8227         return (dns_resolver_createfetch3(res, name, type, domain,
8228                                           nameservers, forwarders, client, id,
8229                                           options, 0, task, action, arg,
8230                                           rdataset, sigrdataset, fetchp));
8231 }
8232
8233 isc_result_t
8234 dns_resolver_createfetch3(dns_resolver_t *res, dns_name_t *name,
8235                           dns_rdatatype_t type,
8236                           dns_name_t *domain, dns_rdataset_t *nameservers,
8237                           dns_forwarders_t *forwarders,
8238                           isc_sockaddr_t *client, dns_messageid_t id,
8239                           unsigned int options, unsigned int depth,
8240                           isc_task_t *task,
8241                           isc_taskaction_t action, void *arg,
8242                           dns_rdataset_t *rdataset,
8243                           dns_rdataset_t *sigrdataset,
8244                           dns_fetch_t **fetchp)
8245 {
8246         dns_fetch_t *fetch;
8247         fetchctx_t *fctx = NULL;
8248         isc_result_t result = ISC_R_SUCCESS;
8249         unsigned int bucketnum;
8250         isc_boolean_t new_fctx = ISC_FALSE;
8251         isc_event_t *event;
8252         unsigned int count = 0;
8253         unsigned int spillat;
8254         unsigned int spillatmin;
8255         isc_boolean_t destroy = ISC_FALSE;
8256
8257         UNUSED(forwarders);
8258
8259         REQUIRE(VALID_RESOLVER(res));
8260         REQUIRE(res->frozen);
8261         /* XXXRTH  Check for meta type */
8262         if (domain != NULL) {
8263                 REQUIRE(DNS_RDATASET_VALID(nameservers));
8264                 REQUIRE(nameservers->type == dns_rdatatype_ns);
8265         } else
8266                 REQUIRE(nameservers == NULL);
8267         REQUIRE(forwarders == NULL);
8268         REQUIRE(!dns_rdataset_isassociated(rdataset));
8269         REQUIRE(sigrdataset == NULL ||
8270                 !dns_rdataset_isassociated(sigrdataset));
8271         REQUIRE(fetchp != NULL && *fetchp == NULL);
8272
8273         log_fetch(name, type);
8274
8275         /*
8276          * XXXRTH  use a mempool?
8277          */
8278         fetch = isc_mem_get(res->mctx, sizeof(*fetch));
8279         if (fetch == NULL)
8280                 return (ISC_R_NOMEMORY);
8281
8282         bucketnum = dns_name_fullhash(name, ISC_FALSE) % res->nbuckets;
8283
8284         LOCK(&res->lock);
8285         spillat = res->spillat;
8286         spillatmin = res->spillatmin;
8287         UNLOCK(&res->lock);
8288         LOCK(&res->buckets[bucketnum].lock);
8289
8290         if (res->buckets[bucketnum].exiting) {
8291                 result = ISC_R_SHUTTINGDOWN;
8292                 goto unlock;
8293         }
8294
8295         if ((options & DNS_FETCHOPT_UNSHARED) == 0) {
8296                 for (fctx = ISC_LIST_HEAD(res->buckets[bucketnum].fctxs);
8297                      fctx != NULL;
8298                      fctx = ISC_LIST_NEXT(fctx, link)) {
8299                         if (fctx_match(fctx, name, type, options))
8300                                 break;
8301                 }
8302         }
8303
8304         /*
8305          * Is this a duplicate?
8306          */
8307         if (fctx != NULL && client != NULL) {
8308                 dns_fetchevent_t *fevent;
8309                 for (fevent = ISC_LIST_HEAD(fctx->events);
8310                      fevent != NULL;
8311                      fevent = ISC_LIST_NEXT(fevent, ev_link)) {
8312                         if (fevent->client != NULL && fevent->id == id &&
8313                             isc_sockaddr_equal(fevent->client, client)) {
8314                                 result = DNS_R_DUPLICATE;
8315                                 goto unlock;
8316                         }
8317                         count++;
8318                 }
8319         }
8320         if (count >= spillatmin && spillatmin != 0) {
8321                 INSIST(fctx != NULL);
8322                 if (count >= spillat)
8323                         fctx->spilled = ISC_TRUE;
8324                 if (fctx->spilled) {
8325                         result = DNS_R_DROP;
8326                         goto unlock;
8327                 }
8328         }
8329
8330         if (fctx == NULL) {
8331                 result = fctx_create(res, name, type, domain, nameservers,
8332                                      options, bucketnum, depth, &fctx);
8333                 if (result != ISC_R_SUCCESS)
8334                         goto unlock;
8335                 new_fctx = ISC_TRUE;
8336         } else if (fctx->depth > depth)
8337                 fctx->depth = depth;
8338
8339         result = fctx_join(fctx, task, client, id, action, arg,
8340                            rdataset, sigrdataset, fetch);
8341         if (new_fctx) {
8342                 if (result == ISC_R_SUCCESS) {
8343                         /*
8344                          * Launch this fctx.
8345                          */
8346                         event = &fctx->control_event;
8347                         ISC_EVENT_INIT(event, sizeof(*event), 0, NULL,
8348                                        DNS_EVENT_FETCHCONTROL,
8349                                        fctx_start, fctx, NULL,
8350                                        NULL, NULL);
8351                         isc_task_send(res->buckets[bucketnum].task, &event);
8352                 } else {
8353                         /*
8354                          * We don't care about the result of fctx_unlink()
8355                          * since we know we're not exiting.
8356                          */
8357                         (void)fctx_unlink(fctx);
8358                         destroy = ISC_TRUE;
8359                 }
8360         }
8361
8362  unlock:
8363         UNLOCK(&res->buckets[bucketnum].lock);
8364
8365         if (destroy)
8366                 fctx_destroy(fctx);
8367
8368         if (result == ISC_R_SUCCESS) {
8369                 FTRACE("created");
8370                 *fetchp = fetch;
8371         } else
8372                 isc_mem_put(res->mctx, fetch, sizeof(*fetch));
8373
8374         return (result);
8375 }
8376
8377 void
8378 dns_resolver_cancelfetch(dns_fetch_t *fetch) {
8379         fetchctx_t *fctx;
8380         dns_resolver_t *res;
8381         dns_fetchevent_t *event, *next_event;
8382         isc_task_t *etask;
8383
8384         REQUIRE(DNS_FETCH_VALID(fetch));
8385         fctx = fetch->private;
8386         REQUIRE(VALID_FCTX(fctx));
8387         res = fctx->res;
8388
8389         FTRACE("cancelfetch");
8390
8391         LOCK(&res->buckets[fctx->bucketnum].lock);
8392
8393         /*
8394          * Find the completion event for this fetch (as opposed
8395          * to those for other fetches that have joined the same
8396          * fctx) and send it with result = ISC_R_CANCELED.
8397          */
8398         event = NULL;
8399         if (fctx->state != fetchstate_done) {
8400                 for (event = ISC_LIST_HEAD(fctx->events);
8401                      event != NULL;
8402                      event = next_event) {
8403                         next_event = ISC_LIST_NEXT(event, ev_link);
8404                         if (event->fetch == fetch) {
8405                                 ISC_LIST_UNLINK(fctx->events, event, ev_link);
8406                                 break;
8407                         }
8408                 }
8409         }
8410         if (event != NULL) {
8411                 etask = event->ev_sender;
8412                 event->ev_sender = fctx;
8413                 event->result = ISC_R_CANCELED;
8414                 isc_task_sendanddetach(&etask, ISC_EVENT_PTR(&event));
8415         }
8416         /*
8417          * The fctx continues running even if no fetches remain;
8418          * the answer is still cached.
8419          */
8420
8421         UNLOCK(&res->buckets[fctx->bucketnum].lock);
8422 }
8423
8424 void
8425 dns_resolver_destroyfetch(dns_fetch_t **fetchp) {
8426         dns_fetch_t *fetch;
8427         dns_resolver_t *res;
8428         dns_fetchevent_t *event, *next_event;
8429         fetchctx_t *fctx;
8430         unsigned int bucketnum;
8431         isc_boolean_t bucket_empty;
8432
8433         REQUIRE(fetchp != NULL);
8434         fetch = *fetchp;
8435         REQUIRE(DNS_FETCH_VALID(fetch));
8436         fctx = fetch->private;
8437         REQUIRE(VALID_FCTX(fctx));
8438         res = fctx->res;
8439
8440         FTRACE("destroyfetch");
8441
8442         bucketnum = fctx->bucketnum;
8443         LOCK(&res->buckets[bucketnum].lock);
8444
8445         /*
8446          * Sanity check: the caller should have gotten its event before
8447          * trying to destroy the fetch.
8448          */
8449         event = NULL;
8450         if (fctx->state != fetchstate_done) {
8451                 for (event = ISC_LIST_HEAD(fctx->events);
8452                      event != NULL;
8453                      event = next_event) {
8454                         next_event = ISC_LIST_NEXT(event, ev_link);
8455                         RUNTIME_CHECK(event->fetch != fetch);
8456                 }
8457         }
8458
8459         bucket_empty = fctx_decreference(fctx);
8460
8461         UNLOCK(&res->buckets[bucketnum].lock);
8462
8463         isc_mem_put(res->mctx, fetch, sizeof(*fetch));
8464         *fetchp = NULL;
8465
8466         if (bucket_empty)
8467                 empty_bucket(res);
8468 }
8469
8470 void
8471 dns_resolver_logfetch(dns_fetch_t *fetch, isc_log_t *lctx,
8472                       isc_logcategory_t *category, isc_logmodule_t *module,
8473                       int level, isc_boolean_t duplicateok)
8474 {
8475         fetchctx_t *fctx;
8476         dns_resolver_t *res;
8477         char domainbuf[DNS_NAME_FORMATSIZE];
8478
8479         REQUIRE(DNS_FETCH_VALID(fetch));
8480         fctx = fetch->private;
8481         REQUIRE(VALID_FCTX(fctx));
8482         res = fctx->res;
8483
8484         LOCK(&res->buckets[fctx->bucketnum].lock);
8485
8486         INSIST(fctx->exitline >= 0);
8487         if (!fctx->logged || duplicateok) {
8488                 dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
8489                 isc_log_write(lctx, category, module, level,
8490                               "fetch completed at %s:%d for %s in "
8491                               "%" ISC_PRINT_QUADFORMAT "u."
8492                               "%06" ISC_PRINT_QUADFORMAT "u: %s/%s "
8493                               "[domain:%s,referral:%u,restart:%u,qrysent:%u,"
8494                               "timeout:%u,lame:%u,neterr:%u,badresp:%u,"
8495                               "adberr:%u,findfail:%u,valfail:%u]",
8496                               __FILE__, fctx->exitline, fctx->info,
8497                               fctx->duration / US_PER_SEC,
8498                               fctx->duration % US_PER_SEC,
8499                               isc_result_totext(fctx->result),
8500                               isc_result_totext(fctx->vresult), domainbuf,
8501                               fctx->referrals, fctx->restarts,
8502                               fctx->querysent, fctx->timeouts, fctx->lamecount,
8503                               fctx->neterr, fctx->badresp, fctx->adberr,
8504                               fctx->findfail, fctx->valfail);
8505                 fctx->logged = ISC_TRUE;
8506         }
8507
8508         UNLOCK(&res->buckets[fctx->bucketnum].lock);
8509 }
8510
8511 dns_dispatchmgr_t *
8512 dns_resolver_dispatchmgr(dns_resolver_t *resolver) {
8513         REQUIRE(VALID_RESOLVER(resolver));
8514         return (resolver->dispatchmgr);
8515 }
8516
8517 dns_dispatch_t *
8518 dns_resolver_dispatchv4(dns_resolver_t *resolver) {
8519         REQUIRE(VALID_RESOLVER(resolver));
8520         return (dns_dispatchset_get(resolver->dispatches4));
8521 }
8522
8523 dns_dispatch_t *
8524 dns_resolver_dispatchv6(dns_resolver_t *resolver) {
8525         REQUIRE(VALID_RESOLVER(resolver));
8526         return (dns_dispatchset_get(resolver->dispatches6));
8527 }
8528
8529 isc_socketmgr_t *
8530 dns_resolver_socketmgr(dns_resolver_t *resolver) {
8531         REQUIRE(VALID_RESOLVER(resolver));
8532         return (resolver->socketmgr);
8533 }
8534
8535 isc_taskmgr_t *
8536 dns_resolver_taskmgr(dns_resolver_t *resolver) {
8537         REQUIRE(VALID_RESOLVER(resolver));
8538         return (resolver->taskmgr);
8539 }
8540
8541 isc_uint32_t
8542 dns_resolver_getlamettl(dns_resolver_t *resolver) {
8543         REQUIRE(VALID_RESOLVER(resolver));
8544         return (resolver->lame_ttl);
8545 }
8546
8547 void
8548 dns_resolver_setlamettl(dns_resolver_t *resolver, isc_uint32_t lame_ttl) {
8549         REQUIRE(VALID_RESOLVER(resolver));
8550         resolver->lame_ttl = lame_ttl;
8551 }
8552
8553 unsigned int
8554 dns_resolver_nrunning(dns_resolver_t *resolver) {
8555         unsigned int n;
8556         LOCK(&resolver->nlock);
8557         n = resolver->nfctx;
8558         UNLOCK(&resolver->nlock);
8559         return (n);
8560 }
8561
8562 isc_result_t
8563 dns_resolver_addalternate(dns_resolver_t *resolver, isc_sockaddr_t *alt,
8564                           dns_name_t *name, in_port_t port) {
8565         alternate_t *a;
8566         isc_result_t result;
8567
8568         REQUIRE(VALID_RESOLVER(resolver));
8569         REQUIRE(!resolver->frozen);
8570         REQUIRE((alt == NULL) ^ (name == NULL));
8571
8572         a = isc_mem_get(resolver->mctx, sizeof(*a));
8573         if (a == NULL)
8574                 return (ISC_R_NOMEMORY);
8575         if (alt != NULL) {
8576                 a->isaddress = ISC_TRUE;
8577                 a->_u.addr = *alt;
8578         } else {
8579                 a->isaddress = ISC_FALSE;
8580                 a->_u._n.port = port;
8581                 dns_name_init(&a->_u._n.name, NULL);
8582                 result = dns_name_dup(name, resolver->mctx, &a->_u._n.name);
8583                 if (result != ISC_R_SUCCESS) {
8584                         isc_mem_put(resolver->mctx, a, sizeof(*a));
8585                         return (result);
8586                 }
8587         }
8588         ISC_LINK_INIT(a, link);
8589         ISC_LIST_APPEND(resolver->alternates, a, link);
8590
8591         return (ISC_R_SUCCESS);
8592 }
8593
8594 void
8595 dns_resolver_setudpsize(dns_resolver_t *resolver, isc_uint16_t udpsize) {
8596         REQUIRE(VALID_RESOLVER(resolver));
8597         resolver->udpsize = udpsize;
8598 }
8599
8600 isc_uint16_t
8601 dns_resolver_getudpsize(dns_resolver_t *resolver) {
8602         REQUIRE(VALID_RESOLVER(resolver));
8603         return (resolver->udpsize);
8604 }
8605
8606 void
8607 dns_resolver_flushbadcache(dns_resolver_t *resolver, dns_name_t *name) {
8608         unsigned int i;
8609         dns_badcache_t *bad, *prev, *next;
8610
8611         REQUIRE(VALID_RESOLVER(resolver));
8612
8613         LOCK(&resolver->lock);
8614         if (resolver->badcache == NULL)
8615                 goto unlock;
8616
8617         if (name != NULL) {
8618                 isc_time_t now;
8619                 isc_result_t result;
8620                 result = isc_time_now(&now);
8621                 if (result != ISC_R_SUCCESS)
8622                         isc_time_settoepoch(&now);
8623                 i = dns_name_hash(name, ISC_FALSE) % resolver->badhash;
8624                 prev = NULL;
8625                 for (bad = resolver->badcache[i]; bad != NULL; bad = next) {
8626                         int n;
8627                         next = bad->next;
8628                         n = isc_time_compare(&bad->expire, &now);
8629                         if (n < 0 || dns_name_equal(name, &bad->name)) {
8630                                 if (prev == NULL)
8631                                         resolver->badcache[i] = bad->next;
8632                                 else
8633                                         prev->next = bad->next;
8634                                 isc_mem_put(resolver->mctx, bad, sizeof(*bad) +
8635                                             bad->name.length);
8636                                 resolver->badcount--;
8637                         } else
8638                                 prev = bad;
8639                 }
8640         } else
8641                 destroy_badcache(resolver);
8642
8643  unlock:
8644         UNLOCK(&resolver->lock);
8645
8646 }
8647
8648 static void
8649 resizehash(dns_resolver_t *resolver, isc_time_t *now, isc_boolean_t grow) {
8650         unsigned int newsize;
8651         dns_badcache_t **new, *bad, *next;
8652         unsigned int i;
8653
8654         if (grow)
8655                 newsize = resolver->badhash * 2 + 1;
8656         else
8657                 newsize = (resolver->badhash - 1) / 2;
8658
8659         new = isc_mem_get(resolver->mctx,
8660                           sizeof(*resolver->badcache) * newsize);
8661         if (new == NULL)
8662                 return;
8663         memset(new, 0, sizeof(*resolver->badcache) * newsize);
8664         for (i = 0; i < resolver->badhash; i++) {
8665                 for (bad = resolver->badcache[i]; bad != NULL; bad = next) {
8666                         next = bad->next;
8667                         if (isc_time_compare(&bad->expire, now) < 0) {
8668                                 isc_mem_put(resolver->mctx, bad, sizeof(*bad) +
8669                                             bad->name.length);
8670                                 resolver->badcount--;
8671                         } else {
8672                                 bad->next = new[bad->hashval % newsize];
8673                                 new[bad->hashval % newsize] = bad;
8674                         }
8675                 }
8676         }
8677         isc_mem_put(resolver->mctx, resolver->badcache,
8678                     sizeof(*resolver->badcache) * resolver->badhash);
8679         resolver->badhash = newsize;
8680         resolver->badcache = new;
8681 }
8682
8683 void
8684 dns_resolver_addbadcache(dns_resolver_t *resolver, dns_name_t *name,
8685                          dns_rdatatype_t type, isc_time_t *expire)
8686 {
8687         isc_time_t now;
8688         isc_result_t result = ISC_R_SUCCESS;
8689         unsigned int i, hashval;
8690         dns_badcache_t *bad, *prev, *next;
8691
8692         REQUIRE(VALID_RESOLVER(resolver));
8693
8694         LOCK(&resolver->lock);
8695         if (resolver->badcache == NULL) {
8696                 resolver->badcache = isc_mem_get(resolver->mctx,
8697                                                  sizeof(*resolver->badcache) *
8698                                                  DNS_BADCACHE_SIZE);
8699                 if (resolver->badcache == NULL)
8700                         goto cleanup;
8701                 resolver->badhash = DNS_BADCACHE_SIZE;
8702                 memset(resolver->badcache, 0, sizeof(*resolver->badcache) *
8703                        resolver->badhash);
8704         }
8705
8706         result = isc_time_now(&now);
8707         if (result != ISC_R_SUCCESS)
8708                 isc_time_settoepoch(&now);
8709         hashval = dns_name_hash(name, ISC_FALSE);
8710         i = hashval % resolver->badhash;
8711         prev = NULL;
8712         for (bad = resolver->badcache[i]; bad != NULL; bad = next) {
8713                 next = bad->next;
8714                 if (bad->type == type && dns_name_equal(name, &bad->name))
8715                         break;
8716                 if (isc_time_compare(&bad->expire, &now) < 0) {
8717                         if (prev == NULL)
8718                                 resolver->badcache[i] = bad->next;
8719                         else
8720                                 prev->next = bad->next;
8721                         isc_mem_put(resolver->mctx, bad, sizeof(*bad) +
8722                                     bad->name.length);
8723                         resolver->badcount--;
8724                 } else
8725                         prev = bad;
8726         }
8727         if (bad == NULL) {
8728                 isc_buffer_t buffer;
8729                 bad = isc_mem_get(resolver->mctx, sizeof(*bad) + name->length);
8730                 if (bad == NULL)
8731                         goto cleanup;
8732                 bad->type = type;
8733                 bad->hashval = hashval;
8734                 bad->expire = *expire;
8735                 isc_buffer_init(&buffer, bad + 1, name->length);
8736                 dns_name_init(&bad->name, NULL);
8737                 dns_name_copy(name, &bad->name, &buffer);
8738                 bad->next = resolver->badcache[i];
8739                 resolver->badcache[i] = bad;
8740                 resolver->badcount++;
8741                 if (resolver->badcount > resolver->badhash * 8)
8742                         resizehash(resolver, &now, ISC_TRUE);
8743                 if (resolver->badcount < resolver->badhash * 2 &&
8744                     resolver->badhash > DNS_BADCACHE_SIZE)
8745                         resizehash(resolver, &now, ISC_FALSE);
8746         } else
8747                 bad->expire = *expire;
8748  cleanup:
8749         UNLOCK(&resolver->lock);
8750 }
8751
8752 isc_boolean_t
8753 dns_resolver_getbadcache(dns_resolver_t *resolver, dns_name_t *name,
8754                          dns_rdatatype_t type, isc_time_t *now)
8755 {
8756         dns_badcache_t *bad, *prev, *next;
8757         isc_boolean_t answer = ISC_FALSE;
8758         unsigned int i;
8759
8760         REQUIRE(VALID_RESOLVER(resolver));
8761
8762         LOCK(&resolver->lock);
8763         if (resolver->badcache == NULL)
8764                 goto unlock;
8765
8766         i = dns_name_hash(name, ISC_FALSE) % resolver->badhash;
8767         prev = NULL;
8768         for (bad = resolver->badcache[i]; bad != NULL; bad = next) {
8769                 next = bad->next;
8770                 /*
8771                  * Search the hash list. Clean out expired records as we go.
8772                  */
8773                 if (isc_time_compare(&bad->expire, now) < 0) {
8774                         if (prev != NULL)
8775                                 prev->next = bad->next;
8776                         else
8777                                 resolver->badcache[i] = bad->next;
8778                         isc_mem_put(resolver->mctx, bad, sizeof(*bad) +
8779                                     bad->name.length);
8780                         resolver->badcount--;
8781                         continue;
8782                 }
8783                 if (bad->type == type && dns_name_equal(name, &bad->name)) {
8784                         answer = ISC_TRUE;
8785                         break;
8786                 }
8787                 prev = bad;
8788         }
8789
8790         /*
8791          * Slow sweep to clean out stale records.
8792          */
8793         i = resolver->badsweep++ % resolver->badhash;
8794         bad = resolver->badcache[i];
8795         if (bad != NULL && isc_time_compare(&bad->expire, now) < 0) {
8796                 resolver->badcache[i] = bad->next;
8797                 isc_mem_put(resolver->mctx, bad, sizeof(*bad) +
8798                             bad->name.length);
8799                 resolver->badcount--;
8800         }
8801
8802  unlock:
8803         UNLOCK(&resolver->lock);
8804         return (answer);
8805 }
8806
8807 void
8808 dns_resolver_printbadcache(dns_resolver_t *resolver, FILE *fp) {
8809         char namebuf[DNS_NAME_FORMATSIZE];
8810         char typebuf[DNS_RDATATYPE_FORMATSIZE];
8811         dns_badcache_t *bad, *next, *prev;
8812         isc_time_t now;
8813         unsigned int i;
8814         isc_uint64_t t;
8815
8816         LOCK(&resolver->lock);
8817         fprintf(fp, ";\n; Bad cache\n;\n");
8818
8819         if (resolver->badcache == NULL)
8820                 goto unlock;
8821
8822         TIME_NOW(&now);
8823         for (i = 0; i < resolver->badhash; i++) {
8824                 prev = NULL;
8825                 for (bad = resolver->badcache[i]; bad != NULL; bad = next) {
8826                         next = bad->next;
8827                         if (isc_time_compare(&bad->expire, &now) < 0) {
8828                                 if (prev != NULL)
8829                                         prev->next = bad->next;
8830                                 else
8831                                         resolver->badcache[i] = bad->next;
8832                                 isc_mem_put(resolver->mctx, bad, sizeof(*bad) +
8833                                             bad->name.length);
8834                                 resolver->badcount--;
8835                                 continue;
8836                         }
8837                         prev = bad;
8838                         dns_name_format(&bad->name, namebuf, sizeof(namebuf));
8839                         dns_rdatatype_format(bad->type, typebuf,
8840                                              sizeof(typebuf));
8841                         t = isc_time_microdiff(&bad->expire, &now);
8842                         t /= 1000;
8843                         fprintf(fp, "; %s/%s [ttl "
8844                                 "%" ISC_PLATFORM_QUADFORMAT "u]\n",
8845                                 namebuf, typebuf, t);
8846                 }
8847         }
8848
8849  unlock:
8850         UNLOCK(&resolver->lock);
8851 }
8852
8853 static void
8854 free_algorithm(void *node, void *arg) {
8855         unsigned char *algorithms = node;
8856         isc_mem_t *mctx = arg;
8857
8858         isc_mem_put(mctx, algorithms, *algorithms);
8859 }
8860
8861 void
8862 dns_resolver_reset_algorithms(dns_resolver_t *resolver) {
8863
8864         REQUIRE(VALID_RESOLVER(resolver));
8865
8866 #if USE_ALGLOCK
8867         RWLOCK(&resolver->alglock, isc_rwlocktype_write);
8868 #endif
8869         if (resolver->algorithms != NULL)
8870                 dns_rbt_destroy(&resolver->algorithms);
8871 #if USE_ALGLOCK
8872         RWUNLOCK(&resolver->alglock, isc_rwlocktype_write);
8873 #endif
8874 }
8875
8876 isc_result_t
8877 dns_resolver_disable_algorithm(dns_resolver_t *resolver, dns_name_t *name,
8878                                unsigned int alg)
8879 {
8880         unsigned int len, mask;
8881         unsigned char *new;
8882         unsigned char *algorithms;
8883         isc_result_t result;
8884         dns_rbtnode_t *node = NULL;
8885
8886         REQUIRE(VALID_RESOLVER(resolver));
8887         if (alg > 255)
8888                 return (ISC_R_RANGE);
8889
8890 #if USE_ALGLOCK
8891         RWLOCK(&resolver->alglock, isc_rwlocktype_write);
8892 #endif
8893         if (resolver->algorithms == NULL) {
8894                 result = dns_rbt_create(resolver->mctx, free_algorithm,
8895                                         resolver->mctx, &resolver->algorithms);
8896                 if (result != ISC_R_SUCCESS)
8897                         goto cleanup;
8898         }
8899
8900         len = alg/8 + 2;
8901         mask = 1 << (alg%8);
8902
8903         result = dns_rbt_addnode(resolver->algorithms, name, &node);
8904
8905         if (result == ISC_R_SUCCESS || result == ISC_R_EXISTS) {
8906                 algorithms = node->data;
8907                 if (algorithms == NULL || len > *algorithms) {
8908                         new = isc_mem_get(resolver->mctx, len);
8909                         if (new == NULL) {
8910                                 result = ISC_R_NOMEMORY;
8911                                 goto cleanup;
8912                         }
8913                         memset(new, 0, len);
8914                         if (algorithms != NULL)
8915                                 memmove(new, algorithms, *algorithms);
8916                         new[len-1] |= mask;
8917                         *new = len;
8918                         node->data = new;
8919                         if (algorithms != NULL)
8920                                 isc_mem_put(resolver->mctx, algorithms,
8921                                             *algorithms);
8922                 } else
8923                         algorithms[len-1] |= mask;
8924         }
8925         result = ISC_R_SUCCESS;
8926  cleanup:
8927 #if USE_ALGLOCK
8928         RWUNLOCK(&resolver->alglock, isc_rwlocktype_write);
8929 #endif
8930         return (result);
8931 }
8932
8933 isc_boolean_t
8934 dns_resolver_algorithm_supported(dns_resolver_t *resolver, dns_name_t *name,
8935                                  unsigned int alg)
8936 {
8937         unsigned int len, mask;
8938         unsigned char *algorithms;
8939         void *data = NULL;
8940         isc_result_t result;
8941         isc_boolean_t found = ISC_FALSE;
8942
8943         REQUIRE(VALID_RESOLVER(resolver));
8944
8945         /*
8946          * DH is unsupported for DNSKEYs, see RFC 4034 sec. A.1.
8947          */
8948         if ((alg == DST_ALG_DH) || (alg == DST_ALG_INDIRECT))
8949                 return (ISC_FALSE);
8950
8951 #if USE_ALGLOCK
8952         RWLOCK(&resolver->alglock, isc_rwlocktype_read);
8953 #endif
8954         if (resolver->algorithms == NULL)
8955                 goto unlock;
8956         result = dns_rbt_findname(resolver->algorithms, name, 0, NULL, &data);
8957         if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
8958                 len = alg/8 + 2;
8959                 mask = 1 << (alg%8);
8960                 algorithms = data;
8961                 if (len <= *algorithms && (algorithms[len-1] & mask) != 0)
8962                         found = ISC_TRUE;
8963         }
8964  unlock:
8965 #if USE_ALGLOCK
8966         RWUNLOCK(&resolver->alglock, isc_rwlocktype_read);
8967 #endif
8968         if (found)
8969                 return (ISC_FALSE);
8970
8971         return (dst_algorithm_supported(alg));
8972 }
8973
8974 isc_boolean_t
8975 dns_resolver_digest_supported(dns_resolver_t *resolver, unsigned int digest) {
8976
8977         UNUSED(resolver);
8978         return (dns_ds_digest_supported(digest));
8979 }
8980
8981 void
8982 dns_resolver_resetmustbesecure(dns_resolver_t *resolver) {
8983
8984         REQUIRE(VALID_RESOLVER(resolver));
8985
8986 #if USE_MBSLOCK
8987         RWLOCK(&resolver->mbslock, isc_rwlocktype_write);
8988 #endif
8989         if (resolver->mustbesecure != NULL)
8990                 dns_rbt_destroy(&resolver->mustbesecure);
8991 #if USE_MBSLOCK
8992         RWUNLOCK(&resolver->mbslock, isc_rwlocktype_write);
8993 #endif
8994 }
8995
8996 static isc_boolean_t yes = ISC_TRUE, no = ISC_FALSE;
8997
8998 isc_result_t
8999 dns_resolver_setmustbesecure(dns_resolver_t *resolver, dns_name_t *name,
9000                              isc_boolean_t value)
9001 {
9002         isc_result_t result;
9003
9004         REQUIRE(VALID_RESOLVER(resolver));
9005
9006 #if USE_MBSLOCK
9007         RWLOCK(&resolver->mbslock, isc_rwlocktype_write);
9008 #endif
9009         if (resolver->mustbesecure == NULL) {
9010                 result = dns_rbt_create(resolver->mctx, NULL, NULL,
9011                                         &resolver->mustbesecure);
9012                 if (result != ISC_R_SUCCESS)
9013                         goto cleanup;
9014         }
9015         result = dns_rbt_addname(resolver->mustbesecure, name,
9016                                  value ? &yes : &no);
9017  cleanup:
9018 #if USE_MBSLOCK
9019         RWUNLOCK(&resolver->mbslock, isc_rwlocktype_write);
9020 #endif
9021         return (result);
9022 }
9023
9024 isc_boolean_t
9025 dns_resolver_getmustbesecure(dns_resolver_t *resolver, dns_name_t *name) {
9026         void *data = NULL;
9027         isc_boolean_t value = ISC_FALSE;
9028         isc_result_t result;
9029
9030         REQUIRE(VALID_RESOLVER(resolver));
9031
9032 #if USE_MBSLOCK
9033         RWLOCK(&resolver->mbslock, isc_rwlocktype_read);
9034 #endif
9035         if (resolver->mustbesecure == NULL)
9036                 goto unlock;
9037         result = dns_rbt_findname(resolver->mustbesecure, name, 0, NULL, &data);
9038         if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
9039                 value = *(isc_boolean_t*)data;
9040  unlock:
9041 #if USE_MBSLOCK
9042         RWUNLOCK(&resolver->mbslock, isc_rwlocktype_read);
9043 #endif
9044         return (value);
9045 }
9046
9047 void
9048 dns_resolver_getclientsperquery(dns_resolver_t *resolver, isc_uint32_t *cur,
9049                                 isc_uint32_t *min, isc_uint32_t *max)
9050 {
9051         REQUIRE(VALID_RESOLVER(resolver));
9052
9053         LOCK(&resolver->lock);
9054         if (cur != NULL)
9055                 *cur = resolver->spillat;
9056         if (min != NULL)
9057                 *min = resolver->spillatmin;
9058         if (max != NULL)
9059                 *max = resolver->spillatmax;
9060         UNLOCK(&resolver->lock);
9061 }
9062
9063 void
9064 dns_resolver_setclientsperquery(dns_resolver_t *resolver, isc_uint32_t min,
9065                                 isc_uint32_t max)
9066 {
9067         REQUIRE(VALID_RESOLVER(resolver));
9068
9069         LOCK(&resolver->lock);
9070         resolver->spillatmin = resolver->spillat = min;
9071         resolver->spillatmax = max;
9072         UNLOCK(&resolver->lock);
9073 }
9074
9075 isc_boolean_t
9076 dns_resolver_getzeronosoattl(dns_resolver_t *resolver) {
9077         REQUIRE(VALID_RESOLVER(resolver));
9078
9079         return (resolver->zero_no_soa_ttl);
9080 }
9081
9082 void
9083 dns_resolver_setzeronosoattl(dns_resolver_t *resolver, isc_boolean_t state) {
9084         REQUIRE(VALID_RESOLVER(resolver));
9085
9086         resolver->zero_no_soa_ttl = state;
9087 }
9088
9089 unsigned int
9090 dns_resolver_getoptions(dns_resolver_t *resolver) {
9091         REQUIRE(VALID_RESOLVER(resolver));
9092
9093         return (resolver->options);
9094 }
9095
9096 unsigned int
9097 dns_resolver_gettimeout(dns_resolver_t *resolver) {
9098         REQUIRE(VALID_RESOLVER(resolver));
9099
9100         return (resolver->query_timeout);
9101 }
9102
9103 void
9104 dns_resolver_settimeout(dns_resolver_t *resolver, unsigned int seconds) {
9105         REQUIRE(VALID_RESOLVER(resolver));
9106
9107         if (seconds == 0)
9108                 seconds = DEFAULT_QUERY_TIMEOUT;
9109         if (seconds > MAXIMUM_QUERY_TIMEOUT)
9110                 seconds = MAXIMUM_QUERY_TIMEOUT;
9111         if (seconds < MINIMUM_QUERY_TIMEOUT)
9112                 seconds =  MINIMUM_QUERY_TIMEOUT;
9113
9114         resolver->query_timeout = seconds;
9115 }
9116
9117 void
9118 dns_resolver_setmaxdepth(dns_resolver_t *resolver, unsigned int maxdepth) {
9119         REQUIRE(VALID_RESOLVER(resolver));
9120         resolver->maxdepth = maxdepth;
9121 }
9122
9123 unsigned int
9124 dns_resolver_getmaxdepth(dns_resolver_t *resolver) {
9125         REQUIRE(VALID_RESOLVER(resolver));
9126         return (resolver->maxdepth);
9127 }