contrib/bind9/lib/dns/lookup.c

   1 /*
   2  * Copyright (C) 2004, 2005  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000, 2001, 2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and 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: lookup.c,v 1.14.18.4 2005/11/30 03:44:39 marka Exp $ */
  19
  20 /*! \file */
  21
  22 #include <config.h>
  23
  24 #include <isc/mem.h>
  25 #include <isc/netaddr.h>
  26 #include <isc/string.h>         /* Required for HP/UX (and others?) */
  27 #include <isc/task.h>
  28 #include <isc/util.h>
  29
  30 #include <dns/db.h>
  31 #include <dns/events.h>
  32 #include <dns/lookup.h>
  33 #include <dns/rdata.h>
  34 #include <dns/rdataset.h>
  35 #include <dns/rdatastruct.h>
  36 #include <dns/resolver.h>
  37 #include <dns/result.h>
  38 #include <dns/view.h>
  39
  40 struct dns_lookup {
  41         /* Unlocked. */
  42         unsigned int            magic;
  43         isc_mem_t *             mctx;
  44         isc_mutex_t             lock;
  45         dns_rdatatype_t         type;
  46         dns_fixedname_t         name;
  47         /* Locked by lock. */
  48         unsigned int            options;
  49         isc_task_t *            task;
  50         dns_view_t *            view;
  51         dns_lookupevent_t *     event;
  52         dns_fetch_t *           fetch;
  53         unsigned int            restarts;
  54         isc_boolean_t           canceled;
  55         dns_rdataset_t          rdataset;
  56         dns_rdataset_t          sigrdataset;
  57 };
  58
  59 #define LOOKUP_MAGIC                    ISC_MAGIC('l', 'o', 'o', 'k')
  60 #define VALID_LOOKUP(l)                 ISC_MAGIC_VALID((l), LOOKUP_MAGIC)
  61
  62 #define MAX_RESTARTS 16
  63
  64 static void lookup_find(dns_lookup_t *lookup, dns_fetchevent_t *event);
  65
  66 static void
  67 fetch_done(isc_task_t *task, isc_event_t *event) {
  68         dns_lookup_t *lookup = event->ev_arg;
  69         dns_fetchevent_t *fevent;
  70
  71         UNUSED(task);
  72         REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE);
  73         REQUIRE(VALID_LOOKUP(lookup));
  74         REQUIRE(lookup->task == task);
  75         fevent = (dns_fetchevent_t *)event;
  76         REQUIRE(fevent->fetch == lookup->fetch);
  77
  78         lookup_find(lookup, fevent);
  79 }
  80
  81 static inline isc_result_t
  82 start_fetch(dns_lookup_t *lookup) {
  83         isc_result_t result;
  84
  85         /*
  86          * The caller must be holding the lookup's lock.
  87          */
  88
  89         REQUIRE(lookup->fetch == NULL);
  90
  91         result = dns_resolver_createfetch(lookup->view->resolver,
  92                                           dns_fixedname_name(&lookup->name),
  93                                           lookup->type,
  94                                           NULL, NULL, NULL, 0,
  95                                           lookup->task, fetch_done, lookup,
  96                                           &lookup->rdataset,
  97                                           &lookup->sigrdataset,
  98                                           &lookup->fetch);
  99
 100         return (result);
 101 }
 102
 103 static isc_result_t
 104 build_event(dns_lookup_t *lookup) {
 105         dns_name_t *name = NULL;
 106         dns_rdataset_t *rdataset = NULL;
 107         dns_rdataset_t *sigrdataset = NULL;
 108         isc_result_t result;
 109
 110         name = isc_mem_get(lookup->mctx, sizeof(dns_name_t));
 111         if (name == NULL) {
 112                 result = ISC_R_NOMEMORY;
 113                 goto fail;
 114         }
 115         dns_name_init(name, NULL);
 116         result = dns_name_dup(dns_fixedname_name(&lookup->name),
 117                               lookup->mctx, name);
 118         if (result != ISC_R_SUCCESS)
 119                 goto fail;
 120
 121         if (dns_rdataset_isassociated(&lookup->rdataset)) {
 122                 rdataset = isc_mem_get(lookup->mctx, sizeof(dns_rdataset_t));
 123                 if (rdataset == NULL) {
 124                         result = ISC_R_NOMEMORY;
 125                         goto fail;
 126                 }
 127                 dns_rdataset_init(rdataset);
 128                 dns_rdataset_clone(&lookup->rdataset, rdataset);
 129         }
 130
 131         if (dns_rdataset_isassociated(&lookup->sigrdataset)) {
 132                 sigrdataset = isc_mem_get(lookup->mctx,
 133                                           sizeof(dns_rdataset_t));
 134                 if (sigrdataset == NULL) {
 135                         result = ISC_R_NOMEMORY;
 136                         goto fail;
 137                 }
 138                 dns_rdataset_init(sigrdataset);
 139                 dns_rdataset_clone(&lookup->sigrdataset, sigrdataset);
 140         }
 141
 142         lookup->event->name = name;
 143         lookup->event->rdataset = rdataset;
 144         lookup->event->sigrdataset = sigrdataset;
 145
 146         return (ISC_R_SUCCESS);
 147
 148  fail:
 149         if (name != NULL) {
 150                 if (dns_name_dynamic(name))
 151                         dns_name_free(name, lookup->mctx);
 152                 isc_mem_put(lookup->mctx, name, sizeof(dns_name_t));
 153         }
 154         if (rdataset != NULL) {
 155                 if (dns_rdataset_isassociated(rdataset))
 156                         dns_rdataset_disassociate(rdataset);
 157                 isc_mem_put(lookup->mctx, rdataset, sizeof(dns_rdataset_t));
 158         }
 159         return (result);
 160 }
 161
 162 static isc_result_t
 163 view_find(dns_lookup_t *lookup, dns_name_t *foundname) {
 164         isc_result_t result;
 165         dns_name_t *name = dns_fixedname_name(&lookup->name);
 166         dns_rdatatype_t type;
 167
 168         if (lookup->type == dns_rdatatype_rrsig)
 169                 type = dns_rdatatype_any;
 170         else
 171                 type = lookup->type;
 172
 173         result = dns_view_find(lookup->view, name, type, 0, 0, ISC_FALSE,
 174                                &lookup->event->db, &lookup->event->node,
 175                                foundname, &lookup->rdataset,
 176                                &lookup->sigrdataset);
 177         return (result);
 178 }
 179
 180 static void
 181 lookup_find(dns_lookup_t *lookup, dns_fetchevent_t *event) {
 182         isc_result_t result;
 183         isc_boolean_t want_restart;
 184         isc_boolean_t send_event = ISC_FALSE;
 185         dns_name_t *name, *fname, *prefix;
 186         dns_fixedname_t foundname, fixed;
 187         dns_rdata_t rdata = DNS_RDATA_INIT;
 188         unsigned int nlabels;
 189         int order;
 190         dns_namereln_t namereln;
 191         dns_rdata_cname_t cname;
 192         dns_rdata_dname_t dname;
 193
 194         REQUIRE(VALID_LOOKUP(lookup));
 195
 196         LOCK(&lookup->lock);
 197
 198         result = ISC_R_SUCCESS;
 199         name = dns_fixedname_name(&lookup->name);
 200
 201         do {
 202                 lookup->restarts++;
 203                 want_restart = ISC_FALSE;
 204
 205                 if (event == NULL && !lookup->canceled) {
 206                         dns_fixedname_init(&foundname);
 207                         fname = dns_fixedname_name(&foundname);
 208                         INSIST(!dns_rdataset_isassociated(&lookup->rdataset));
 209                         INSIST(!dns_rdataset_isassociated
 210                                                 (&lookup->sigrdataset));
 211                         result = view_find(lookup, fname);
 212                         if (result == ISC_R_NOTFOUND) {
 213                                 /*
 214                                  * We don't know anything about the name.
 215                                  * Launch a fetch.
 216                                  */
 217                                 if  (lookup->event->node != NULL) {
 218                                         INSIST(lookup->event->db != NULL);
 219                                         dns_db_detachnode(lookup->event->db,
 220                                                          &lookup->event->node);
 221                                 }
 222                                 if (lookup->event->db != NULL)
 223                                         dns_db_detach(&lookup->event->db);
 224                                 result = start_fetch(lookup);
 225                                 if (result != ISC_R_SUCCESS)
 226                                         send_event = ISC_TRUE;
 227                                 goto done;
 228                         }
 229                 } else if (event != NULL) {
 230                         result = event->result;
 231                         fname = dns_fixedname_name(&event->foundname);
 232                         dns_resolver_destroyfetch(&lookup->fetch);
 233                         INSIST(event->rdataset == &lookup->rdataset);
 234                         INSIST(event->sigrdataset == &lookup->sigrdataset);
 235                 } else
 236                         fname = NULL;   /* Silence compiler warning. */
 237
 238                 /*
 239                  * If we've been canceled, forget about the result.
 240                  */
 241                 if (lookup->canceled)
 242                         result = ISC_R_CANCELED;
 243
 244                 switch (result) {
 245                 case ISC_R_SUCCESS:
 246                         result = build_event(lookup);
 247                         send_event = ISC_TRUE;
 248                         if (event == NULL)
 249                                 break;
 250                         if (event->db != NULL)
 251                                 dns_db_attach(event->db, &lookup->event->db);
 252                         if (event->node != NULL)
 253                                 dns_db_attachnode(lookup->event->db,
 254                                                   event->node,
 255                                                   &lookup->event->node);
 256                         break;
 257                 case DNS_R_CNAME:
 258                         /*
 259                          * Copy the CNAME's target into the lookup's
 260                          * query name and start over.
 261                          */
 262                         result = dns_rdataset_first(&lookup->rdataset);
 263                         if (result != ISC_R_SUCCESS)
 264                                 break;
 265                         dns_rdataset_current(&lookup->rdataset, &rdata);
 266                         result = dns_rdata_tostruct(&rdata, &cname, NULL);
 267                         dns_rdata_reset(&rdata);
 268                         if (result != ISC_R_SUCCESS)
 269                                 break;
 270                         result = dns_name_copy(&cname.cname, name, NULL);
 271                         dns_rdata_freestruct(&cname);
 272                         if (result == ISC_R_SUCCESS)
 273                                 want_restart = ISC_TRUE;
 274                         break;
 275                 case DNS_R_DNAME:
 276                         namereln = dns_name_fullcompare(name, fname, &order,
 277                                                         &nlabels);
 278                         INSIST(namereln == dns_namereln_subdomain);
 279                         /*
 280                          * Get the target name of the DNAME.
 281                          */
 282                         result = dns_rdataset_first(&lookup->rdataset);
 283                         if (result != ISC_R_SUCCESS)
 284                                 break;
 285                         dns_rdataset_current(&lookup->rdataset, &rdata);
 286                         result = dns_rdata_tostruct(&rdata, &dname, NULL);
 287                         dns_rdata_reset(&rdata);
 288                         if (result != ISC_R_SUCCESS)
 289                                 break;
 290                         /*
 291                          * Construct the new query name and start over.
 292                          */
 293                         dns_fixedname_init(&fixed);
 294                         prefix = dns_fixedname_name(&fixed);
 295                         dns_name_split(name, nlabels, prefix, NULL);
 296                         result = dns_name_concatenate(prefix, &dname.dname,
 297                                                       name, NULL);
 298                         dns_rdata_freestruct(&dname);
 299                         if (result == ISC_R_SUCCESS)
 300                                 want_restart = ISC_TRUE;
 301                         break;
 302                 default:
 303                         send_event = ISC_TRUE;
 304                 }
 305
 306                 if (dns_rdataset_isassociated(&lookup->rdataset))
 307                         dns_rdataset_disassociate(&lookup->rdataset);
 308                 if (dns_rdataset_isassociated(&lookup->sigrdataset))
 309                         dns_rdataset_disassociate(&lookup->sigrdataset);
 310
 311         done:
 312                 if (event != NULL) {
 313                         if (event->node != NULL)
 314                                 dns_db_detachnode(event->db, &event->node);
 315                         if (event->db != NULL)
 316                                 dns_db_detach(&event->db);
 317                         isc_event_free(ISC_EVENT_PTR(&event));
 318                 }
 319
 320                 /*
 321                  * Limit the number of restarts.
 322                  */
 323                 if (want_restart && lookup->restarts == MAX_RESTARTS) {
 324                         want_restart = ISC_FALSE;
 325                         result = ISC_R_QUOTA;
 326                         send_event = ISC_TRUE;
 327                 }
 328
 329         } while (want_restart);
 330
 331         if (send_event) {
 332                 lookup->event->result = result;
 333                 lookup->event->ev_sender = lookup;
 334                 isc_task_sendanddetach(&lookup->task,
 335                                        (isc_event_t **)&lookup->event);
 336                 dns_view_detach(&lookup->view);
 337         }
 338
 339         UNLOCK(&lookup->lock);
 340 }
 341
 342 static void
 343 levent_destroy(isc_event_t *event) {
 344         dns_lookupevent_t *levent;
 345         isc_mem_t *mctx;
 346
 347         REQUIRE(event->ev_type == DNS_EVENT_LOOKUPDONE);
 348         mctx = event->ev_destroy_arg;
 349         levent = (dns_lookupevent_t *)event;
 350
 351         if (levent->name != NULL) {
 352                 if (dns_name_dynamic(levent->name))
 353                         dns_name_free(levent->name, mctx);
 354                 isc_mem_put(mctx, levent->name, sizeof(dns_name_t));
 355         }
 356         if (levent->rdataset != NULL) {
 357                 dns_rdataset_disassociate(levent->rdataset);
 358                 isc_mem_put(mctx, levent->rdataset, sizeof(dns_rdataset_t));
 359         }
 360         if (levent->sigrdataset != NULL) {
 361                 dns_rdataset_disassociate(levent->sigrdataset);
 362                 isc_mem_put(mctx, levent->sigrdataset, sizeof(dns_rdataset_t));
 363         }
 364         if (levent->node != NULL)
 365                 dns_db_detachnode(levent->db, &levent->node);
 366         if (levent->db != NULL)
 367                 dns_db_detach(&levent->db);
 368         isc_mem_put(mctx, event, event->ev_size);
 369 }
 370
 371
 372 isc_result_t
 373 dns_lookup_create(isc_mem_t *mctx, dns_name_t *name, dns_rdatatype_t type,
 374                   dns_view_t *view, unsigned int options, isc_task_t *task,
 375                   isc_taskaction_t action, void *arg, dns_lookup_t **lookupp)
 376 {
 377         isc_result_t result;
 378         dns_lookup_t *lookup;
 379         isc_event_t *ievent;
 380
 381         lookup = isc_mem_get(mctx, sizeof(*lookup));
 382         if (lookup == NULL)
 383                 return (ISC_R_NOMEMORY);
 384         lookup->mctx = mctx;
 385         lookup->options = options;
 386
 387         ievent = isc_event_allocate(mctx, lookup, DNS_EVENT_LOOKUPDONE,
 388                                     action, arg, sizeof(*lookup->event));
 389         if (ievent == NULL) {
 390                 result = ISC_R_NOMEMORY;
 391                 goto cleanup_lookup;
 392         }
 393         lookup->event = (dns_lookupevent_t *)ievent;
 394         lookup->event->ev_destroy = levent_destroy;
 395         lookup->event->ev_destroy_arg = mctx;
 396         lookup->event->result = ISC_R_FAILURE;
 397         lookup->event->name = NULL;
 398         lookup->event->rdataset = NULL;
 399         lookup->event->sigrdataset = NULL;
 400         lookup->event->db = NULL;
 401         lookup->event->node = NULL;
 402
 403         lookup->task = NULL;
 404         isc_task_attach(task, &lookup->task);
 405
 406         result = isc_mutex_init(&lookup->lock);
 407         if (result != ISC_R_SUCCESS)
 408                 goto cleanup_event;
 409
 410         dns_fixedname_init(&lookup->name);
 411
 412         result = dns_name_copy(name, dns_fixedname_name(&lookup->name), NULL);
 413         if (result != ISC_R_SUCCESS)
 414                 goto cleanup_lock;
 415
 416         lookup->type = type;
 417         lookup->view = NULL;
 418         dns_view_attach(view, &lookup->view);
 419         lookup->fetch = NULL;
 420         lookup->restarts = 0;
 421         lookup->canceled = ISC_FALSE;
 422         dns_rdataset_init(&lookup->rdataset);
 423         dns_rdataset_init(&lookup->sigrdataset);
 424         lookup->magic = LOOKUP_MAGIC;
 425
 426         *lookupp = lookup;
 427
 428         lookup_find(lookup, NULL);
 429
 430         return (ISC_R_SUCCESS);
 431
 432  cleanup_lock:
 433         DESTROYLOCK(&lookup->lock);
 434
 435  cleanup_event:
 436         ievent = (isc_event_t *)lookup->event;
 437         isc_event_free(&ievent);
 438         lookup->event = NULL;
 439
 440         isc_task_detach(&lookup->task);
 441
 442  cleanup_lookup:
 443         isc_mem_put(mctx, lookup, sizeof(*lookup));
 444
 445         return (result);
 446 }
 447
 448 void
 449 dns_lookup_cancel(dns_lookup_t *lookup) {
 450         REQUIRE(VALID_LOOKUP(lookup));
 451
 452         LOCK(&lookup->lock);
 453
 454         if (!lookup->canceled) {
 455                 lookup->canceled = ISC_TRUE;
 456                 if (lookup->fetch != NULL) {
 457                         INSIST(lookup->view != NULL);
 458                         dns_resolver_cancelfetch(lookup->fetch);
 459                 }
 460         }
 461
 462         UNLOCK(&lookup->lock);
 463 }
 464
 465 void
 466 dns_lookup_destroy(dns_lookup_t **lookupp) {
 467         dns_lookup_t *lookup;
 468
 469         REQUIRE(lookupp != NULL);
 470         lookup = *lookupp;
 471         REQUIRE(VALID_LOOKUP(lookup));
 472         REQUIRE(lookup->event == NULL);
 473         REQUIRE(lookup->task == NULL);
 474         REQUIRE(lookup->view == NULL);
 475         if (dns_rdataset_isassociated(&lookup->rdataset))
 476                 dns_rdataset_disassociate(&lookup->rdataset);
 477         if (dns_rdataset_isassociated(&lookup->sigrdataset))
 478                 dns_rdataset_disassociate(&lookup->sigrdataset);
 479
 480         DESTROYLOCK(&lookup->lock);
 481         lookup->magic = 0;
 482         isc_mem_put(lookup->mctx, lookup, sizeof(*lookup));
 483
 484         *lookupp = NULL;
 485 }