contrib/unbound/iterator/iterator.c

   1 /*
   2  * iterator/iterator.c - iterative resolver DNS query response module
   3  *
   4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
   5  *
   6  * This software is open source.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * Redistributions of source code must retain the above copyright notice,
  13  * this list of conditions and the following disclaimer.
  14  *
  15  * Redistributions in binary form must reproduce the above copyright notice,
  16  * this list of conditions and the following disclaimer in the documentation
  17  * and/or other materials provided with the distribution.
  18  *
  19  * Neither the name of the NLNET LABS nor the names of its contributors may
  20  * be used to endorse or promote products derived from this software without
  21  * specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 /**
  37  * \file
  38  *
  39  * This file contains a module that performs recusive iterative DNS query
  40  * processing.
  41  */
  42
  43 #include "config.h"
  44 #include "iterator/iterator.h"
  45 #include "iterator/iter_utils.h"
  46 #include "iterator/iter_hints.h"
  47 #include "iterator/iter_fwd.h"
  48 #include "iterator/iter_donotq.h"
  49 #include "iterator/iter_delegpt.h"
  50 #include "iterator/iter_resptype.h"
  51 #include "iterator/iter_scrub.h"
  52 #include "iterator/iter_priv.h"
  53 #include "validator/val_neg.h"
  54 #include "services/cache/dns.h"
  55 #include "services/cache/infra.h"
  56 #include "util/module.h"
  57 #include "util/netevent.h"
  58 #include "util/net_help.h"
  59 #include "util/regional.h"
  60 #include "util/data/dname.h"
  61 #include "util/data/msgencode.h"
  62 #include "util/fptr_wlist.h"
  63 #include "util/config_file.h"
  64 #include "util/random.h"
  65 #include "sldns/rrdef.h"
  66 #include "sldns/wire2str.h"
  67 #include "sldns/parseutil.h"
  68 #include "sldns/sbuffer.h"
  69
  70 int
  71 iter_init(struct module_env* env, int id)
  72 {
  73         struct iter_env* iter_env = (struct iter_env*)calloc(1,
  74                 sizeof(struct iter_env));
  75         if(!iter_env) {
  76                 log_err("malloc failure");
  77                 return 0;
  78         }
  79         env->modinfo[id] = (void*)iter_env;
  80         if(!iter_apply_cfg(iter_env, env->cfg)) {
  81                 log_err("iterator: could not apply configuration settings.");
  82                 return 0;
  83         }
  84         return 1;
  85 }
  86
  87 /** delete caps_whitelist element */
  88 static void
  89 caps_free(struct rbnode_t* n, void* ATTR_UNUSED(d))
  90 {
  91         if(n) {
  92                 free(((struct name_tree_node*)n)->name);
  93                 free(n);
  94         }
  95 }
  96
  97 void
  98 iter_deinit(struct module_env* env, int id)
  99 {
 100         struct iter_env* iter_env;
 101         if(!env || !env->modinfo[id])
 102                 return;
 103         iter_env = (struct iter_env*)env->modinfo[id];
 104         free(iter_env->target_fetch_policy);
 105         priv_delete(iter_env->priv);
 106         donotq_delete(iter_env->donotq);
 107         if(iter_env->caps_white) {
 108                 traverse_postorder(iter_env->caps_white, caps_free, NULL);
 109                 free(iter_env->caps_white);
 110         }
 111         free(iter_env);
 112         env->modinfo[id] = NULL;
 113 }
 114
 115 /** new query for iterator */
 116 static int
 117 iter_new(struct module_qstate* qstate, int id)
 118 {
 119         struct iter_qstate* iq = (struct iter_qstate*)regional_alloc(
 120                 qstate->region, sizeof(struct iter_qstate));
 121         qstate->minfo[id] = iq;
 122         if(!iq)
 123                 return 0;
 124         memset(iq, 0, sizeof(*iq));
 125         iq->state = INIT_REQUEST_STATE;
 126         iq->final_state = FINISHED_STATE;
 127         iq->an_prepend_list = NULL;
 128         iq->an_prepend_last = NULL;
 129         iq->ns_prepend_list = NULL;
 130         iq->ns_prepend_last = NULL;
 131         iq->dp = NULL;
 132         iq->depth = 0;
 133         iq->num_target_queries = 0;
 134         iq->num_current_queries = 0;
 135         iq->query_restart_count = 0;
 136         iq->referral_count = 0;
 137         iq->sent_count = 0;
 138         iq->ratelimit_ok = 0;
 139         iq->target_count = NULL;
 140         iq->wait_priming_stub = 0;
 141         iq->refetch_glue = 0;
 142         iq->dnssec_expected = 0;
 143         iq->dnssec_lame_query = 0;
 144         iq->chase_flags = qstate->query_flags;
 145         /* Start with the (current) qname. */
 146         iq->qchase = qstate->qinfo;
 147         outbound_list_init(&iq->outlist);
 148         return 1;
 149 }
 150
 151 /**
 152  * Transition to the next state. This can be used to advance a currently
 153  * processing event. It cannot be used to reactivate a forEvent.
 154  *
 155  * @param iq: iterator query state
 156  * @param nextstate The state to transition to.
 157  * @return true. This is so this can be called as the return value for the
 158  *         actual process*State() methods. (Transitioning to the next state
 159  *         implies further processing).
 160  */
 161 static int
 162 next_state(struct iter_qstate* iq, enum iter_state nextstate)
 163 {
 164         /* If transitioning to a "response" state, make sure that there is a
 165          * response */
 166         if(iter_state_is_responsestate(nextstate)) {
 167                 if(iq->response == NULL) {
 168                         log_err("transitioning to response state sans "
 169                                 "response.");
 170                 }
 171         }
 172         iq->state = nextstate;
 173         return 1;
 174 }
 175
 176 /**
 177  * Transition an event to its final state. Final states always either return
 178  * a result up the module chain, or reactivate a dependent event. Which
 179  * final state to transtion to is set in the module state for the event when
 180  * it was created, and depends on the original purpose of the event.
 181  *
 182  * The response is stored in the qstate->buf buffer.
 183  *
 184  * @param iq: iterator query state
 185  * @return false. This is so this method can be used as the return value for
 186  *         the processState methods. (Transitioning to the final state
 187  */
 188 static int
 189 final_state(struct iter_qstate* iq)
 190 {
 191         return next_state(iq, iq->final_state);
 192 }
 193
 194 /**
 195  * Callback routine to handle errors in parent query states
 196  * @param qstate: query state that failed.
 197  * @param id: module id.
 198  * @param super: super state.
 199  */
 200 static void
 201 error_supers(struct module_qstate* qstate, int id, struct module_qstate* super)
 202 {
 203         struct iter_qstate* super_iq = (struct iter_qstate*)super->minfo[id];
 204
 205         if(qstate->qinfo.qtype == LDNS_RR_TYPE_A ||
 206                 qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA) {
 207                 /* mark address as failed. */
 208                 struct delegpt_ns* dpns = NULL;
 209                 if(super_iq->dp)
 210                         dpns = delegpt_find_ns(super_iq->dp,
 211                                 qstate->qinfo.qname, qstate->qinfo.qname_len);
 212                 if(!dpns) {
 213                         /* not interested */
 214                         verbose(VERB_ALGO, "subq error, but not interested");
 215                         log_query_info(VERB_ALGO, "superq", &super->qinfo);
 216                         if(super_iq->dp)
 217                                 delegpt_log(VERB_ALGO, super_iq->dp);
 218                         log_assert(0);
 219                         return;
 220                 } else {
 221                         /* see if the failure did get (parent-lame) info */
 222                         if(!cache_fill_missing(super->env,
 223                                 super_iq->qchase.qclass, super->region,
 224                                 super_iq->dp))
 225                                 log_err("out of memory adding missing");
 226                 }
 227                 dpns->resolved = 1; /* mark as failed */
 228                 super_iq->num_target_queries--;
 229         }
 230         if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS) {
 231                 /* prime failed to get delegation */
 232                 super_iq->dp = NULL;
 233         }
 234         /* evaluate targets again */
 235         super_iq->state = QUERYTARGETS_STATE;
 236         /* super becomes runnable, and will process this change */
 237 }
 238
 239 /**
 240  * Return an error to the client
 241  * @param qstate: our query state
 242  * @param id: module id
 243  * @param rcode: error code (DNS errcode).
 244  * @return: 0 for use by caller, to make notation easy, like:
 245  *      return error_response(..).
 246  */
 247 static int
 248 error_response(struct module_qstate* qstate, int id, int rcode)
 249 {
 250         verbose(VERB_QUERY, "return error response %s",
 251                 sldns_lookup_by_id(sldns_rcodes, rcode)?
 252                 sldns_lookup_by_id(sldns_rcodes, rcode)->name:"??");
 253         qstate->return_rcode = rcode;
 254         qstate->return_msg = NULL;
 255         qstate->ext_state[id] = module_finished;
 256         return 0;
 257 }
 258
 259 /**
 260  * Return an error to the client and cache the error code in the
 261  * message cache (so per qname, qtype, qclass).
 262  * @param qstate: our query state
 263  * @param id: module id
 264  * @param rcode: error code (DNS errcode).
 265  * @return: 0 for use by caller, to make notation easy, like:
 266  *      return error_response(..).
 267  */
 268 static int
 269 error_response_cache(struct module_qstate* qstate, int id, int rcode)
 270 {
 271         /* store in cache */
 272         struct reply_info err;
 273         if(qstate->prefetch_leeway > NORR_TTL) {
 274                 verbose(VERB_ALGO, "error response for prefetch in cache");
 275                 /* attempt to adjust the cache entry prefetch */
 276                 if(dns_cache_prefetch_adjust(qstate->env, &qstate->qinfo,
 277                         NORR_TTL, qstate->query_flags))
 278                         return error_response(qstate, id, rcode);
 279                 /* if that fails (not in cache), fall through to store err */
 280         }
 281         memset(&err, 0, sizeof(err));
 282         err.flags = (uint16_t)(BIT_QR | BIT_RA);
 283         FLAGS_SET_RCODE(err.flags, rcode);
 284         err.qdcount = 1;
 285         err.ttl = NORR_TTL;
 286         err.prefetch_ttl = PREFETCH_TTL_CALC(err.ttl);
 287         /* do not waste time trying to validate this servfail */
 288         err.security = sec_status_indeterminate;
 289         verbose(VERB_ALGO, "store error response in message cache");
 290         iter_dns_store(qstate->env, &qstate->qinfo, &err, 0, 0, 0, NULL,
 291                 qstate->query_flags);
 292         return error_response(qstate, id, rcode);
 293 }
 294
 295 /** check if prepend item is duplicate item */
 296 static int
 297 prepend_is_duplicate(struct ub_packed_rrset_key** sets, size_t to,
 298         struct ub_packed_rrset_key* dup)
 299 {
 300         size_t i;
 301         for(i=0; i<to; i++) {
 302                 if(sets[i]->rk.type == dup->rk.type &&
 303                         sets[i]->rk.rrset_class == dup->rk.rrset_class &&
 304                         sets[i]->rk.dname_len == dup->rk.dname_len &&
 305                         query_dname_compare(sets[i]->rk.dname, dup->rk.dname)
 306                         == 0)
 307                         return 1;
 308         }
 309         return 0;
 310 }
 311
 312 /** prepend the prepend list in the answer and authority section of dns_msg */
 313 static int
 314 iter_prepend(struct iter_qstate* iq, struct dns_msg* msg,
 315         struct regional* region)
 316 {
 317         struct iter_prep_list* p;
 318         struct ub_packed_rrset_key** sets;
 319         size_t num_an = 0, num_ns = 0;;
 320         for(p = iq->an_prepend_list; p; p = p->next)
 321                 num_an++;
 322         for(p = iq->ns_prepend_list; p; p = p->next)
 323                 num_ns++;
 324         if(num_an + num_ns == 0)
 325                 return 1;
 326         verbose(VERB_ALGO, "prepending %d rrsets", (int)num_an + (int)num_ns);
 327         if(num_an > RR_COUNT_MAX || num_ns > RR_COUNT_MAX ||
 328                 msg->rep->rrset_count > RR_COUNT_MAX) return 0; /* overflow */
 329         sets = regional_alloc(region, (num_an+num_ns+msg->rep->rrset_count) *
 330                 sizeof(struct ub_packed_rrset_key*));
 331         if(!sets)
 332                 return 0;
 333         /* ANSWER section */
 334         num_an = 0;
 335         for(p = iq->an_prepend_list; p; p = p->next) {
 336                 sets[num_an++] = p->rrset;
 337         }
 338         memcpy(sets+num_an, msg->rep->rrsets, msg->rep->an_numrrsets *
 339                 sizeof(struct ub_packed_rrset_key*));
 340         /* AUTH section */
 341         num_ns = 0;
 342         for(p = iq->ns_prepend_list; p; p = p->next) {
 343                 if(prepend_is_duplicate(sets+msg->rep->an_numrrsets+num_an,
 344                         num_ns, p->rrset) || prepend_is_duplicate(
 345                         msg->rep->rrsets+msg->rep->an_numrrsets,
 346                         msg->rep->ns_numrrsets, p->rrset))
 347                         continue;
 348                 sets[msg->rep->an_numrrsets + num_an + num_ns++] = p->rrset;
 349         }
 350         memcpy(sets + num_an + msg->rep->an_numrrsets + num_ns,
 351                 msg->rep->rrsets + msg->rep->an_numrrsets,
 352                 (msg->rep->ns_numrrsets + msg->rep->ar_numrrsets) *
 353                 sizeof(struct ub_packed_rrset_key*));
 354
 355         /* NXDOMAIN rcode can stay if we prepended DNAME/CNAMEs, because
 356          * this is what recursors should give. */
 357         msg->rep->rrset_count += num_an + num_ns;
 358         msg->rep->an_numrrsets += num_an;
 359         msg->rep->ns_numrrsets += num_ns;
 360         msg->rep->rrsets = sets;
 361         return 1;
 362 }
 363
 364 /**
 365  * Add rrset to ANSWER prepend list
 366  * @param qstate: query state.
 367  * @param iq: iterator query state.
 368  * @param rrset: rrset to add.
 369  * @return false on failure (malloc).
 370  */
 371 static int
 372 iter_add_prepend_answer(struct module_qstate* qstate, struct iter_qstate* iq,
 373         struct ub_packed_rrset_key* rrset)
 374 {
 375         struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc(
 376                 qstate->region, sizeof(struct iter_prep_list));
 377         if(!p)
 378                 return 0;
 379         p->rrset = rrset;
 380         p->next = NULL;
 381         /* add at end */
 382         if(iq->an_prepend_last)
 383                 iq->an_prepend_last->next = p;
 384         else    iq->an_prepend_list = p;
 385         iq->an_prepend_last = p;
 386         return 1;
 387 }
 388
 389 /**
 390  * Add rrset to AUTHORITY prepend list
 391  * @param qstate: query state.
 392  * @param iq: iterator query state.
 393  * @param rrset: rrset to add.
 394  * @return false on failure (malloc).
 395  */
 396 static int
 397 iter_add_prepend_auth(struct module_qstate* qstate, struct iter_qstate* iq,
 398         struct ub_packed_rrset_key* rrset)
 399 {
 400         struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc(
 401                 qstate->region, sizeof(struct iter_prep_list));
 402         if(!p)
 403                 return 0;
 404         p->rrset = rrset;
 405         p->next = NULL;
 406         /* add at end */
 407         if(iq->ns_prepend_last)
 408                 iq->ns_prepend_last->next = p;
 409         else    iq->ns_prepend_list = p;
 410         iq->ns_prepend_last = p;
 411         return 1;
 412 }
 413
 414 /**
 415  * Given a CNAME response (defined as a response containing a CNAME or DNAME
 416  * that does not answer the request), process the response, modifying the
 417  * state as necessary. This follows the CNAME/DNAME chain and returns the
 418  * final query name.
 419  *
 420  * sets the new query name, after following the CNAME/DNAME chain.
 421  * @param qstate: query state.
 422  * @param iq: iterator query state.
 423  * @param msg: the response.
 424  * @param mname: returned target new query name.
 425  * @param mname_len: length of mname.
 426  * @return false on (malloc) error.
 427  */
 428 static int
 429 handle_cname_response(struct module_qstate* qstate, struct iter_qstate* iq,
 430         struct dns_msg* msg, uint8_t** mname, size_t* mname_len)
 431 {
 432         size_t i;
 433         /* Start with the (current) qname. */
 434         *mname = iq->qchase.qname;
 435         *mname_len = iq->qchase.qname_len;
 436
 437         /* Iterate over the ANSWER rrsets in order, looking for CNAMEs and
 438          * DNAMES. */
 439         for(i=0; i<msg->rep->an_numrrsets; i++) {
 440                 struct ub_packed_rrset_key* r = msg->rep->rrsets[i];
 441                 /* If there is a (relevant) DNAME, add it to the list.
 442                  * We always expect there to be CNAME that was generated
 443                  * by this DNAME following, so we don't process the DNAME
 444                  * directly.  */
 445                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_DNAME &&
 446                         dname_strict_subdomain_c(*mname, r->rk.dname)) {
 447                         if(!iter_add_prepend_answer(qstate, iq, r))
 448                                 return 0;
 449                         continue;
 450                 }
 451
 452                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_CNAME &&
 453                         query_dname_compare(*mname, r->rk.dname) == 0) {
 454                         /* Add this relevant CNAME rrset to the prepend list.*/
 455                         if(!iter_add_prepend_answer(qstate, iq, r))
 456                                 return 0;
 457                         get_cname_target(r, mname, mname_len);
 458                 }
 459
 460                 /* Other rrsets in the section are ignored. */
 461         }
 462         /* add authority rrsets to authority prepend, for wildcarded CNAMEs */
 463         for(i=msg->rep->an_numrrsets; i<msg->rep->an_numrrsets +
 464                 msg->rep->ns_numrrsets; i++) {
 465                 struct ub_packed_rrset_key* r = msg->rep->rrsets[i];
 466                 /* only add NSEC/NSEC3, as they may be needed for validation */
 467                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC ||
 468                         ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC3) {
 469                         if(!iter_add_prepend_auth(qstate, iq, r))
 470                                 return 0;
 471                 }
 472         }
 473         return 1;
 474 }
 475
 476 /** see if target name is caps-for-id whitelisted */
 477 static int
 478 is_caps_whitelisted(struct iter_env* ie, struct iter_qstate* iq)
 479 {
 480         if(!ie->caps_white) return 0; /* no whitelist, or no capsforid */
 481         return name_tree_lookup(ie->caps_white, iq->qchase.qname,
 482                 iq->qchase.qname_len, dname_count_labels(iq->qchase.qname),
 483                 iq->qchase.qclass) != NULL;
 484 }
 485
 486 /** create target count structure for this query */
 487 static void
 488 target_count_create(struct iter_qstate* iq)
 489 {
 490         if(!iq->target_count) {
 491                 iq->target_count = (int*)calloc(2, sizeof(int));
 492                 /* if calloc fails we simply do not track this number */
 493                 if(iq->target_count)
 494                         iq->target_count[0] = 1;
 495         }
 496 }
 497
 498 static void
 499 target_count_increase(struct iter_qstate* iq, int num)
 500 {
 501         target_count_create(iq);
 502         if(iq->target_count)
 503                 iq->target_count[1] += num;
 504 }
 505
 506 /**
 507  * Generate a subrequest.
 508  * Generate a local request event. Local events are tied to this module, and
 509  * have a correponding (first tier) event that is waiting for this event to
 510  * resolve to continue.
 511  *
 512  * @param qname The query name for this request.
 513  * @param qnamelen length of qname
 514  * @param qtype The query type for this request.
 515  * @param qclass The query class for this request.
 516  * @param qstate The event that is generating this event.
 517  * @param id: module id.
 518  * @param iq: The iterator state that is generating this event.
 519  * @param initial_state The initial response state (normally this
 520  *          is QUERY_RESP_STATE, unless it is known that the request won't
 521  *          need iterative processing
 522  * @param finalstate The final state for the response to this request.
 523  * @param subq_ret: if newly allocated, the subquerystate, or NULL if it does
 524  *      not need initialisation.
 525  * @param v: if true, validation is done on the subquery.
 526  * @return false on error (malloc).
 527  */
 528 static int
 529 generate_sub_request(uint8_t* qname, size_t qnamelen, uint16_t qtype,
 530         uint16_t qclass, struct module_qstate* qstate, int id,
 531         struct iter_qstate* iq, enum iter_state initial_state,
 532         enum iter_state finalstate, struct module_qstate** subq_ret, int v)
 533 {
 534         struct module_qstate* subq = NULL;
 535         struct iter_qstate* subiq = NULL;
 536         uint16_t qflags = 0; /* OPCODE QUERY, no flags */
 537         struct query_info qinf;
 538         int prime = (finalstate == PRIME_RESP_STATE)?1:0;
 539         int valrec = 0;
 540         qinf.qname = qname;
 541         qinf.qname_len = qnamelen;
 542         qinf.qtype = qtype;
 543         qinf.qclass = qclass;
 544
 545         /* RD should be set only when sending the query back through the INIT
 546          * state. */
 547         if(initial_state == INIT_REQUEST_STATE)
 548                 qflags |= BIT_RD;
 549         /* We set the CD flag so we can send this through the "head" of
 550          * the resolution chain, which might have a validator. We are
 551          * uninterested in validating things not on the direct resolution
 552          * path.  */
 553         if(!v) {
 554                 qflags |= BIT_CD;
 555                 valrec = 1;
 556         }
 557
 558         /* attach subquery, lookup existing or make a new one */
 559         fptr_ok(fptr_whitelist_modenv_attach_sub(qstate->env->attach_sub));
 560         if(!(*qstate->env->attach_sub)(qstate, &qinf, qflags, prime, valrec,
 561                 &subq)) {
 562                 return 0;
 563         }
 564         *subq_ret = subq;
 565         if(subq) {
 566                 /* initialise the new subquery */
 567                 subq->curmod = id;
 568                 subq->ext_state[id] = module_state_initial;
 569                 subq->minfo[id] = regional_alloc(subq->region,
 570                         sizeof(struct iter_qstate));
 571                 if(!subq->minfo[id]) {
 572                         log_err("init subq: out of memory");
 573                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 574                                 qstate->env->kill_sub));
 575                         (*qstate->env->kill_sub)(subq);
 576                         return 0;
 577                 }
 578                 subiq = (struct iter_qstate*)subq->minfo[id];
 579                 memset(subiq, 0, sizeof(*subiq));
 580                 subiq->num_target_queries = 0;
 581                 target_count_create(iq);
 582                 subiq->target_count = iq->target_count;
 583                 if(iq->target_count)
 584                         iq->target_count[0] ++; /* extra reference */
 585                 subiq->num_current_queries = 0;
 586                 subiq->depth = iq->depth+1;
 587                 outbound_list_init(&subiq->outlist);
 588                 subiq->state = initial_state;
 589                 subiq->final_state = finalstate;
 590                 subiq->qchase = subq->qinfo;
 591                 subiq->chase_flags = subq->query_flags;
 592                 subiq->refetch_glue = 0;
 593         }
 594         return 1;
 595 }
 596
 597 /**
 598  * Generate and send a root priming request.
 599  * @param qstate: the qtstate that triggered the need to prime.
 600  * @param iq: iterator query state.
 601  * @param id: module id.
 602  * @param qclass: the class to prime.
 603  * @return 0 on failure
 604  */
 605 static int
 606 prime_root(struct module_qstate* qstate, struct iter_qstate* iq, int id,
 607         uint16_t qclass)
 608 {
 609         struct delegpt* dp;
 610         struct module_qstate* subq;
 611         verbose(VERB_DETAIL, "priming . %s NS",
 612                 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)?
 613                 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)->name:"??");
 614         dp = hints_lookup_root(qstate->env->hints, qclass);
 615         if(!dp) {
 616                 verbose(VERB_ALGO, "Cannot prime due to lack of hints");
 617                 return 0;
 618         }
 619         /* Priming requests start at the QUERYTARGETS state, skipping
 620          * the normal INIT state logic (which would cause an infloop). */
 621         if(!generate_sub_request((uint8_t*)"\000", 1, LDNS_RR_TYPE_NS,
 622                 qclass, qstate, id, iq, QUERYTARGETS_STATE, PRIME_RESP_STATE,
 623                 &subq, 0)) {
 624                 verbose(VERB_ALGO, "could not prime root");
 625                 return 0;
 626         }
 627         if(subq) {
 628                 struct iter_qstate* subiq =
 629                         (struct iter_qstate*)subq->minfo[id];
 630                 /* Set the initial delegation point to the hint.
 631                  * copy dp, it is now part of the root prime query.
 632                  * dp was part of in the fixed hints structure. */
 633                 subiq->dp = delegpt_copy(dp, subq->region);
 634                 if(!subiq->dp) {
 635                         log_err("out of memory priming root, copydp");
 636                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 637                                 qstate->env->kill_sub));
 638                         (*qstate->env->kill_sub)(subq);
 639                         return 0;
 640                 }
 641                 /* there should not be any target queries. */
 642                 subiq->num_target_queries = 0;
 643                 subiq->dnssec_expected = iter_indicates_dnssec(
 644                         qstate->env, subiq->dp, NULL, subq->qinfo.qclass);
 645         }
 646
 647         /* this module stops, our submodule starts, and does the query. */
 648         qstate->ext_state[id] = module_wait_subquery;
 649         return 1;
 650 }
 651
 652 /**
 653  * Generate and process a stub priming request. This method tests for the
 654  * need to prime a stub zone, so it is safe to call for every request.
 655  *
 656  * @param qstate: the qtstate that triggered the need to prime.
 657  * @param iq: iterator query state.
 658  * @param id: module id.
 659  * @param qname: request name.
 660  * @param qclass: request class.
 661  * @return true if a priming subrequest was made, false if not. The will only
 662  *         issue a priming request if it detects an unprimed stub.
 663  *         Uses value of 2 to signal during stub-prime in root-prime situation
 664  *         that a noprime-stub is available and resolution can continue.
 665  */
 666 static int
 667 prime_stub(struct module_qstate* qstate, struct iter_qstate* iq, int id,
 668         uint8_t* qname, uint16_t qclass)
 669 {
 670         /* Lookup the stub hint. This will return null if the stub doesn't
 671          * need to be re-primed. */
 672         struct iter_hints_stub* stub;
 673         struct delegpt* stub_dp;
 674         struct module_qstate* subq;
 675
 676         if(!qname) return 0;
 677         stub = hints_lookup_stub(qstate->env->hints, qname, qclass, iq->dp);
 678         /* The stub (if there is one) does not need priming. */
 679         if(!stub)
 680                 return 0;
 681         stub_dp = stub->dp;
 682
 683         /* is it a noprime stub (always use) */
 684         if(stub->noprime) {
 685                 int r = 0;
 686                 if(iq->dp == NULL) r = 2;
 687                 /* copy the dp out of the fixed hints structure, so that
 688                  * it can be changed when servicing this query */
 689                 iq->dp = delegpt_copy(stub_dp, qstate->region);
 690                 if(!iq->dp) {
 691                         log_err("out of memory priming stub");
 692                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 693                         return 1; /* return 1 to make module stop, with error */
 694                 }
 695                 log_nametypeclass(VERB_DETAIL, "use stub", stub_dp->name,
 696                         LDNS_RR_TYPE_NS, qclass);
 697                 return r;
 698         }
 699
 700         /* Otherwise, we need to (re)prime the stub. */
 701         log_nametypeclass(VERB_DETAIL, "priming stub", stub_dp->name,
 702                 LDNS_RR_TYPE_NS, qclass);
 703
 704         /* Stub priming events start at the QUERYTARGETS state to avoid the
 705          * redundant INIT state processing. */
 706         if(!generate_sub_request(stub_dp->name, stub_dp->namelen,
 707                 LDNS_RR_TYPE_NS, qclass, qstate, id, iq,
 708                 QUERYTARGETS_STATE, PRIME_RESP_STATE, &subq, 0)) {
 709                 verbose(VERB_ALGO, "could not prime stub");
 710                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 711                 return 1; /* return 1 to make module stop, with error */
 712         }
 713         if(subq) {
 714                 struct iter_qstate* subiq =
 715                         (struct iter_qstate*)subq->minfo[id];
 716
 717                 /* Set the initial delegation point to the hint. */
 718                 /* make copy to avoid use of stub dp by different qs/threads */
 719                 subiq->dp = delegpt_copy(stub_dp, subq->region);
 720                 if(!subiq->dp) {
 721                         log_err("out of memory priming stub, copydp");
 722                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 723                                 qstate->env->kill_sub));
 724                         (*qstate->env->kill_sub)(subq);
 725                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 726                         return 1; /* return 1 to make module stop, with error */
 727                 }
 728                 /* there should not be any target queries -- although there
 729                  * wouldn't be anyway, since stub hints never have
 730                  * missing targets. */
 731                 subiq->num_target_queries = 0;
 732                 subiq->wait_priming_stub = 1;
 733                 subiq->dnssec_expected = iter_indicates_dnssec(
 734                         qstate->env, subiq->dp, NULL, subq->qinfo.qclass);
 735         }
 736
 737         /* this module stops, our submodule starts, and does the query. */
 738         qstate->ext_state[id] = module_wait_subquery;
 739         return 1;
 740 }
 741
 742 /**
 743  * Generate A and AAAA checks for glue that is in-zone for the referral
 744  * we just got to obtain authoritative information on the adresses.
 745  *
 746  * @param qstate: the qtstate that triggered the need to prime.
 747  * @param iq: iterator query state.
 748  * @param id: module id.
 749  */
 750 static void
 751 generate_a_aaaa_check(struct module_qstate* qstate, struct iter_qstate* iq,
 752         int id)
 753 {
 754         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
 755         struct module_qstate* subq;
 756         size_t i;
 757         struct reply_info* rep = iq->response->rep;
 758         struct ub_packed_rrset_key* s;
 759         log_assert(iq->dp);
 760
 761         if(iq->depth == ie->max_dependency_depth)
 762                 return;
 763         /* walk through additional, and check if in-zone,
 764          * only relevant A, AAAA are left after scrub anyway */
 765         for(i=rep->an_numrrsets+rep->ns_numrrsets; i<rep->rrset_count; i++) {
 766                 s = rep->rrsets[i];
 767                 /* check *ALL* addresses that are transmitted in additional*/
 768                 /* is it an address ? */
 769                 if( !(ntohs(s->rk.type)==LDNS_RR_TYPE_A ||
 770                         ntohs(s->rk.type)==LDNS_RR_TYPE_AAAA)) {
 771                         continue;
 772                 }
 773                 /* is this query the same as the A/AAAA check for it */
 774                 if(qstate->qinfo.qtype == ntohs(s->rk.type) &&
 775                         qstate->qinfo.qclass == ntohs(s->rk.rrset_class) &&
 776                         query_dname_compare(qstate->qinfo.qname,
 777                                 s->rk.dname)==0 &&
 778                         (qstate->query_flags&BIT_RD) &&
 779                         !(qstate->query_flags&BIT_CD))
 780                         continue;
 781
 782                 /* generate subrequest for it */
 783                 log_nametypeclass(VERB_ALGO, "schedule addr fetch",
 784                         s->rk.dname, ntohs(s->rk.type),
 785                         ntohs(s->rk.rrset_class));
 786                 if(!generate_sub_request(s->rk.dname, s->rk.dname_len,
 787                         ntohs(s->rk.type), ntohs(s->rk.rrset_class),
 788                         qstate, id, iq,
 789                         INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) {
 790                         verbose(VERB_ALGO, "could not generate addr check");
 791                         return;
 792                 }
 793                 /* ignore subq - not need for more init */
 794         }
 795 }
 796
 797 /**
 798  * Generate a NS check request to obtain authoritative information
 799  * on an NS rrset.
 800  *
 801  * @param qstate: the qtstate that triggered the need to prime.
 802  * @param iq: iterator query state.
 803  * @param id: module id.
 804  */
 805 static void
 806 generate_ns_check(struct module_qstate* qstate, struct iter_qstate* iq, int id)
 807 {
 808         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
 809         struct module_qstate* subq;
 810         log_assert(iq->dp);
 811
 812         if(iq->depth == ie->max_dependency_depth)
 813                 return;
 814         /* is this query the same as the nscheck? */
 815         if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS &&
 816                 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 &&
 817                 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){
 818                 /* spawn off A, AAAA queries for in-zone glue to check */
 819                 generate_a_aaaa_check(qstate, iq, id);
 820                 return;
 821         }
 822
 823         log_nametypeclass(VERB_ALGO, "schedule ns fetch",
 824                 iq->dp->name, LDNS_RR_TYPE_NS, iq->qchase.qclass);
 825         if(!generate_sub_request(iq->dp->name, iq->dp->namelen,
 826                 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
 827                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) {
 828                 verbose(VERB_ALGO, "could not generate ns check");
 829                 return;
 830         }
 831         if(subq) {
 832                 struct iter_qstate* subiq =
 833                         (struct iter_qstate*)subq->minfo[id];
 834
 835                 /* make copy to avoid use of stub dp by different qs/threads */
 836                 /* refetch glue to start higher up the tree */
 837                 subiq->refetch_glue = 1;
 838                 subiq->dp = delegpt_copy(iq->dp, subq->region);
 839                 if(!subiq->dp) {
 840                         log_err("out of memory generating ns check, copydp");
 841                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 842                                 qstate->env->kill_sub));
 843                         (*qstate->env->kill_sub)(subq);
 844                         return;
 845                 }
 846         }
 847 }
 848
 849 /**
 850  * Generate a DNSKEY prefetch query to get the DNSKEY for the DS record we
 851  * just got in a referral (where we have dnssec_expected, thus have trust
 852  * anchors above it).  Note that right after calling this routine the
 853  * iterator detached subqueries (because of following the referral), and thus
 854  * the DNSKEY query becomes detached, its return stored in the cache for
 855  * later lookup by the validator.  This cache lookup by the validator avoids
 856  * the roundtrip incurred by the DNSKEY query.  The DNSKEY query is now
 857  * performed at about the same time the original query is sent to the domain,
 858  * thus the two answers are likely to be returned at about the same time,
 859  * saving a roundtrip from the validated lookup.
 860  *
 861  * @param qstate: the qtstate that triggered the need to prime.
 862  * @param iq: iterator query state.
 863  * @param id: module id.
 864  */
 865 static void
 866 generate_dnskey_prefetch(struct module_qstate* qstate,
 867         struct iter_qstate* iq, int id)
 868 {
 869         struct module_qstate* subq;
 870         log_assert(iq->dp);
 871
 872         /* is this query the same as the prefetch? */
 873         if(qstate->qinfo.qtype == LDNS_RR_TYPE_DNSKEY &&
 874                 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 &&
 875                 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){
 876                 return;
 877         }
 878
 879         /* if the DNSKEY is in the cache this lookup will stop quickly */
 880         log_nametypeclass(VERB_ALGO, "schedule dnskey prefetch",
 881                 iq->dp->name, LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass);
 882         if(!generate_sub_request(iq->dp->name, iq->dp->namelen,
 883                 LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass, qstate, id, iq,
 884                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0)) {
 885                 /* we'll be slower, but it'll work */
 886                 verbose(VERB_ALGO, "could not generate dnskey prefetch");
 887                 return;
 888         }
 889         if(subq) {
 890                 struct iter_qstate* subiq =
 891                         (struct iter_qstate*)subq->minfo[id];
 892                 /* this qstate has the right delegation for the dnskey lookup*/
 893                 /* make copy to avoid use of stub dp by different qs/threads */
 894                 subiq->dp = delegpt_copy(iq->dp, subq->region);
 895                 /* if !subiq->dp, it'll start from the cache, no problem */
 896         }
 897 }
 898
 899 /**
 900  * See if the query needs forwarding.
 901  *
 902  * @param qstate: query state.
 903  * @param iq: iterator query state.
 904  * @return true if the request is forwarded, false if not.
 905  *      If returns true but, iq->dp is NULL then a malloc failure occurred.
 906  */
 907 static int
 908 forward_request(struct module_qstate* qstate, struct iter_qstate* iq)
 909 {
 910         struct delegpt* dp;
 911         uint8_t* delname = iq->qchase.qname;
 912         size_t delnamelen = iq->qchase.qname_len;
 913         if(iq->refetch_glue) {
 914                 delname = iq->dp->name;
 915                 delnamelen = iq->dp->namelen;
 916         }
 917         /* strip one label off of DS query to lookup higher for it */
 918         if( (iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue)
 919                 && !dname_is_root(iq->qchase.qname))
 920                 dname_remove_label(&delname, &delnamelen);
 921         dp = forwards_lookup(qstate->env->fwds, delname, iq->qchase.qclass);
 922         if(!dp)
 923                 return 0;
 924         /* send recursion desired to forward addr */
 925         iq->chase_flags |= BIT_RD;
 926         iq->dp = delegpt_copy(dp, qstate->region);
 927         /* iq->dp checked by caller */
 928         verbose(VERB_ALGO, "forwarding request");
 929         return 1;
 930 }
 931
 932 /**
 933  * Process the initial part of the request handling. This state roughly
 934  * corresponds to resolver algorithms steps 1 (find answer in cache) and 2
 935  * (find the best servers to ask).
 936  *
 937  * Note that all requests start here, and query restarts revisit this state.
 938  *
 939  * This state either generates: 1) a response, from cache or error, 2) a
 940  * priming event, or 3) forwards the request to the next state (init2,
 941  * generally).
 942  *
 943  * @param qstate: query state.
 944  * @param iq: iterator query state.
 945  * @param ie: iterator shared global environment.
 946  * @param id: module id.
 947  * @return true if the event needs more request processing immediately,
 948  *         false if not.
 949  */
 950 static int
 951 processInitRequest(struct module_qstate* qstate, struct iter_qstate* iq,
 952         struct iter_env* ie, int id)
 953 {
 954         uint8_t* delname;
 955         size_t delnamelen;
 956         struct dns_msg* msg;
 957
 958         log_query_info(VERB_DETAIL, "resolving", &qstate->qinfo);
 959         /* check effort */
 960
 961         /* We enforce a maximum number of query restarts. This is primarily a
 962          * cheap way to prevent CNAME loops. */
 963         if(iq->query_restart_count > MAX_RESTART_COUNT) {
 964                 verbose(VERB_QUERY, "request has exceeded the maximum number"
 965                         " of query restarts with %d", iq->query_restart_count);
 966                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 967         }
 968
 969         /* We enforce a maximum recursion/dependency depth -- in general,
 970          * this is unnecessary for dependency loops (although it will
 971          * catch those), but it provides a sensible limit to the amount
 972          * of work required to answer a given query. */
 973         verbose(VERB_ALGO, "request has dependency depth of %d", iq->depth);
 974         if(iq->depth > ie->max_dependency_depth) {
 975                 verbose(VERB_QUERY, "request has exceeded the maximum "
 976                         "dependency depth with depth of %d", iq->depth);
 977                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 978         }
 979
 980         /* If the request is qclass=ANY, setup to generate each class */
 981         if(qstate->qinfo.qclass == LDNS_RR_CLASS_ANY) {
 982                 iq->qchase.qclass = 0;
 983                 return next_state(iq, COLLECT_CLASS_STATE);
 984         }
 985
 986         /* Resolver Algorithm Step 1 -- Look for the answer in local data. */
 987
 988         /* This either results in a query restart (CNAME cache response), a
 989          * terminating response (ANSWER), or a cache miss (null). */
 990
 991         if(qstate->blacklist) {
 992                 /* if cache, or anything else, was blacklisted then
 993                  * getting older results from cache is a bad idea, no cache */
 994                 verbose(VERB_ALGO, "cache blacklisted, going to the network");
 995                 msg = NULL;
 996         } else {
 997                 msg = dns_cache_lookup(qstate->env, iq->qchase.qname,
 998                         iq->qchase.qname_len, iq->qchase.qtype,
 999                         iq->qchase.qclass, qstate->query_flags,
1000                         qstate->region, qstate->env->scratch);
1001                 if(!msg && qstate->env->neg_cache) {
1002                         /* lookup in negative cache; may result in
1003                          * NOERROR/NODATA or NXDOMAIN answers that need validation */
1004                         msg = val_neg_getmsg(qstate->env->neg_cache, &iq->qchase,
1005                                 qstate->region, qstate->env->rrset_cache,
1006                                 qstate->env->scratch_buffer,
1007                                 *qstate->env->now, 1/*add SOA*/, NULL);
1008                 }
1009                 /* item taken from cache does not match our query name, thus
1010                  * security needs to be re-examined later */
1011                 if(msg && query_dname_compare(qstate->qinfo.qname,
1012                         iq->qchase.qname) != 0)
1013                         msg->rep->security = sec_status_unchecked;
1014         }
1015         if(msg) {
1016                 /* handle positive cache response */
1017                 enum response_type type = response_type_from_cache(msg,
1018                         &iq->qchase);
1019                 if(verbosity >= VERB_ALGO) {
1020                         log_dns_msg("msg from cache lookup", &msg->qinfo,
1021                                 msg->rep);
1022                         verbose(VERB_ALGO, "msg ttl is %d, prefetch ttl %d",
1023                                 (int)msg->rep->ttl,
1024                                 (int)msg->rep->prefetch_ttl);
1025                 }
1026
1027                 if(type == RESPONSE_TYPE_CNAME) {
1028                         uint8_t* sname = 0;
1029                         size_t slen = 0;
1030                         verbose(VERB_ALGO, "returning CNAME response from "
1031                                 "cache");
1032                         if(!handle_cname_response(qstate, iq, msg,
1033                                 &sname, &slen))
1034                                 return error_response(qstate, id,
1035                                         LDNS_RCODE_SERVFAIL);
1036                         iq->qchase.qname = sname;
1037                         iq->qchase.qname_len = slen;
1038                         /* This *is* a query restart, even if it is a cheap
1039                          * one. */
1040                         iq->dp = NULL;
1041                         iq->refetch_glue = 0;
1042                         iq->query_restart_count++;
1043                         iq->sent_count = 0;
1044                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1045                         return next_state(iq, INIT_REQUEST_STATE);
1046                 }
1047
1048                 /* if from cache, NULL, else insert 'cache IP' len=0 */
1049                 if(qstate->reply_origin)
1050                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1051                 /* it is an answer, response, to final state */
1052                 verbose(VERB_ALGO, "returning answer from cache.");
1053                 iq->response = msg;
1054                 return final_state(iq);
1055         }
1056
1057         /* attempt to forward the request */
1058         if(forward_request(qstate, iq))
1059         {
1060                 if(!iq->dp) {
1061                         log_err("alloc failure for forward dp");
1062                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1063                 }
1064                 iq->refetch_glue = 0;
1065                 /* the request has been forwarded.
1066                  * forwarded requests need to be immediately sent to the
1067                  * next state, QUERYTARGETS. */
1068                 return next_state(iq, QUERYTARGETS_STATE);
1069         }
1070
1071         /* Resolver Algorithm Step 2 -- find the "best" servers. */
1072
1073         /* first, adjust for DS queries. To avoid the grandparent problem,
1074          * we just look for the closest set of server to the parent of qname.
1075          * When re-fetching glue we also need to ask the parent.
1076          */
1077         if(iq->refetch_glue) {
1078                 if(!iq->dp) {
1079                         log_err("internal or malloc fail: no dp for refetch");
1080                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1081                 }
1082                 delname = iq->dp->name;
1083                 delnamelen = iq->dp->namelen;
1084         } else {
1085                 delname = iq->qchase.qname;
1086                 delnamelen = iq->qchase.qname_len;
1087         }
1088         if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue ||
1089            (iq->qchase.qtype == LDNS_RR_TYPE_NS && qstate->prefetch_leeway)) {
1090                 /* remove first label from delname, root goes to hints,
1091                  * but only to fetch glue, not for qtype=DS. */
1092                 /* also when prefetching an NS record, fetch it again from
1093                  * its parent, just as if it expired, so that you do not
1094                  * get stuck on an older nameserver that gives old NSrecords */
1095                 if(dname_is_root(delname) && (iq->refetch_glue ||
1096                         (iq->qchase.qtype == LDNS_RR_TYPE_NS &&
1097                         qstate->prefetch_leeway)))
1098                         delname = NULL; /* go to root priming */
1099                 else    dname_remove_label(&delname, &delnamelen);
1100         }
1101         /* delname is the name to lookup a delegation for. If NULL rootprime */
1102         while(1) {
1103
1104                 /* Lookup the delegation in the cache. If null, then the
1105                  * cache needs to be primed for the qclass. */
1106                 if(delname)
1107                      iq->dp = dns_cache_find_delegation(qstate->env, delname,
1108                         delnamelen, iq->qchase.qtype, iq->qchase.qclass,
1109                         qstate->region, &iq->deleg_msg,
1110                         *qstate->env->now+qstate->prefetch_leeway);
1111                 else iq->dp = NULL;
1112
1113                 /* If the cache has returned nothing, then we have a
1114                  * root priming situation. */
1115                 if(iq->dp == NULL) {
1116                         /* if there is a stub, then no root prime needed */
1117                         int r = prime_stub(qstate, iq, id, delname,
1118                                 iq->qchase.qclass);
1119                         if(r == 2)
1120                                 break; /* got noprime-stub-zone, continue */
1121                         else if(r)
1122                                 return 0; /* stub prime request made */
1123                         if(forwards_lookup_root(qstate->env->fwds,
1124                                 iq->qchase.qclass)) {
1125                                 /* forward zone root, no root prime needed */
1126                                 /* fill in some dp - safety belt */
1127                                 iq->dp = hints_lookup_root(qstate->env->hints,
1128                                         iq->qchase.qclass);
1129                                 if(!iq->dp) {
1130                                         log_err("internal error: no hints dp");
1131                                         return error_response(qstate, id,
1132                                                 LDNS_RCODE_SERVFAIL);
1133                                 }
1134                                 iq->dp = delegpt_copy(iq->dp, qstate->region);
1135                                 if(!iq->dp) {
1136                                         log_err("out of memory in safety belt");
1137                                         return error_response(qstate, id,
1138                                                 LDNS_RCODE_SERVFAIL);
1139                                 }
1140                                 return next_state(iq, INIT_REQUEST_2_STATE);
1141                         }
1142                         /* Note that the result of this will set a new
1143                          * DelegationPoint based on the result of priming. */
1144                         if(!prime_root(qstate, iq, id, iq->qchase.qclass))
1145                                 return error_response(qstate, id,
1146                                         LDNS_RCODE_REFUSED);
1147
1148                         /* priming creates and sends a subordinate query, with
1149                          * this query as the parent. So further processing for
1150                          * this event will stop until reactivated by the
1151                          * results of priming. */
1152                         return 0;
1153                 }
1154                 if(!iq->ratelimit_ok && qstate->prefetch_leeway)
1155                         iq->ratelimit_ok = 1; /* allow prefetches, this keeps
1156                         otherwise valid data in the cache */
1157                 if(!iq->ratelimit_ok && infra_ratelimit_exceeded(
1158                         qstate->env->infra_cache, iq->dp->name,
1159                         iq->dp->namelen, *qstate->env->now)) {
1160                         /* and increment the rate, so that the rate for time
1161                          * now will also exceed the rate, keeping cache fresh */
1162                         (void)infra_ratelimit_inc(qstate->env->infra_cache,
1163                                 iq->dp->name, iq->dp->namelen,
1164                                 *qstate->env->now);
1165                         /* see if we are passed through with slip factor */
1166                         if(qstate->env->cfg->ratelimit_factor != 0 &&
1167                                 ub_random_max(qstate->env->rnd,
1168                                     qstate->env->cfg->ratelimit_factor) == 1) {
1169                                 iq->ratelimit_ok = 1;
1170                                 log_nametypeclass(VERB_ALGO, "ratelimit allowed through for "
1171                                         "delegation point", iq->dp->name,
1172                                         LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
1173                         } else {
1174                                 log_nametypeclass(VERB_ALGO, "ratelimit exceeded with "
1175                                         "delegation point", iq->dp->name,
1176                                         LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
1177                                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1178                         }
1179                 }
1180
1181                 /* see if this dp not useless.
1182                  * It is useless if:
1183                  *      o all NS items are required glue.
1184                  *        or the query is for NS item that is required glue.
1185                  *      o no addresses are provided.
1186                  *      o RD qflag is on.
1187                  * Instead, go up one level, and try to get even further
1188                  * If the root was useless, use safety belt information.
1189                  * Only check cache returns, because replies for servers
1190                  * could be useless but lead to loops (bumping into the
1191                  * same server reply) if useless-checked.
1192                  */
1193                 if(iter_dp_is_useless(&qstate->qinfo, qstate->query_flags,
1194                         iq->dp)) {
1195                         if(dname_is_root(iq->dp->name)) {
1196                                 /* use safety belt */
1197                                 verbose(VERB_QUERY, "Cache has root NS but "
1198                                 "no addresses. Fallback to the safety belt.");
1199                                 iq->dp = hints_lookup_root(qstate->env->hints,
1200                                         iq->qchase.qclass);
1201                                 /* note deleg_msg is from previous lookup,
1202                                  * but RD is on, so it is not used */
1203                                 if(!iq->dp) {
1204                                         log_err("internal error: no hints dp");
1205                                         return error_response(qstate, id,
1206                                                 LDNS_RCODE_REFUSED);
1207                                 }
1208                                 iq->dp = delegpt_copy(iq->dp, qstate->region);
1209                                 if(!iq->dp) {
1210                                         log_err("out of memory in safety belt");
1211                                         return error_response(qstate, id,
1212                                                 LDNS_RCODE_SERVFAIL);
1213                                 }
1214                                 break;
1215                         } else {
1216                                 verbose(VERB_ALGO,
1217                                         "cache delegation was useless:");
1218                                 delegpt_log(VERB_ALGO, iq->dp);
1219                                 /* go up */
1220                                 delname = iq->dp->name;
1221                                 delnamelen = iq->dp->namelen;
1222                                 dname_remove_label(&delname, &delnamelen);
1223                         }
1224                 } else break;
1225         }
1226
1227         verbose(VERB_ALGO, "cache delegation returns delegpt");
1228         delegpt_log(VERB_ALGO, iq->dp);
1229
1230         /* Otherwise, set the current delegation point and move on to the
1231          * next state. */
1232         return next_state(iq, INIT_REQUEST_2_STATE);
1233 }
1234
1235 /**
1236  * Process the second part of the initial request handling. This state
1237  * basically exists so that queries that generate root priming events have
1238  * the same init processing as ones that do not. Request events that reach
1239  * this state must have a valid currentDelegationPoint set.
1240  *
1241  * This part is primarly handling stub zone priming. Events that reach this
1242  * state must have a current delegation point.
1243  *
1244  * @param qstate: query state.
1245  * @param iq: iterator query state.
1246  * @param id: module id.
1247  * @return true if the event needs more request processing immediately,
1248  *         false if not.
1249  */
1250 static int
1251 processInitRequest2(struct module_qstate* qstate, struct iter_qstate* iq,
1252         int id)
1253 {
1254         uint8_t* delname;
1255         size_t delnamelen;
1256         log_query_info(VERB_QUERY, "resolving (init part 2): ",
1257                 &qstate->qinfo);
1258
1259         if(iq->refetch_glue) {
1260                 if(!iq->dp) {
1261                         log_err("internal or malloc fail: no dp for refetch");
1262                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1263                 }
1264                 delname = iq->dp->name;
1265                 delnamelen = iq->dp->namelen;
1266         } else {
1267                 delname = iq->qchase.qname;
1268                 delnamelen = iq->qchase.qname_len;
1269         }
1270         if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue) {
1271                 if(!dname_is_root(delname))
1272                         dname_remove_label(&delname, &delnamelen);
1273                 iq->refetch_glue = 0; /* if CNAME causes restart, no refetch */
1274         }
1275         /* Check to see if we need to prime a stub zone. */
1276         if(prime_stub(qstate, iq, id, delname, iq->qchase.qclass)) {
1277                 /* A priming sub request was made */
1278                 return 0;
1279         }
1280
1281         /* most events just get forwarded to the next state. */
1282         return next_state(iq, INIT_REQUEST_3_STATE);
1283 }
1284
1285 /**
1286  * Process the third part of the initial request handling. This state exists
1287  * as a separate state so that queries that generate stub priming events
1288  * will get the tail end of the init process but not repeat the stub priming
1289  * check.
1290  *
1291  * @param qstate: query state.
1292  * @param iq: iterator query state.
1293  * @param id: module id.
1294  * @return true, advancing the event to the QUERYTARGETS_STATE.
1295  */
1296 static int
1297 processInitRequest3(struct module_qstate* qstate, struct iter_qstate* iq,
1298         int id)
1299 {
1300         log_query_info(VERB_QUERY, "resolving (init part 3): ",
1301                 &qstate->qinfo);
1302         /* if the cache reply dp equals a validation anchor or msg has DS,
1303          * then DNSSEC RRSIGs are expected in the reply */
1304         iq->dnssec_expected = iter_indicates_dnssec(qstate->env, iq->dp,
1305                 iq->deleg_msg, iq->qchase.qclass);
1306
1307         /* If the RD flag wasn't set, then we just finish with the
1308          * cached referral as the response. */
1309         if(!(qstate->query_flags & BIT_RD)) {
1310                 iq->response = iq->deleg_msg;
1311                 if(verbosity >= VERB_ALGO && iq->response)
1312                         log_dns_msg("no RD requested, using delegation msg",
1313                                 &iq->response->qinfo, iq->response->rep);
1314                 if(qstate->reply_origin)
1315                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1316                 return final_state(iq);
1317         }
1318         /* After this point, unset the RD flag -- this query is going to
1319          * be sent to an auth. server. */
1320         iq->chase_flags &= ~BIT_RD;
1321
1322         /* if dnssec expected, fetch key for the trust-anchor or cached-DS */
1323         if(iq->dnssec_expected && qstate->env->cfg->prefetch_key &&
1324                 !(qstate->query_flags&BIT_CD)) {
1325                 generate_dnskey_prefetch(qstate, iq, id);
1326                 fptr_ok(fptr_whitelist_modenv_detach_subs(
1327                         qstate->env->detach_subs));
1328                 (*qstate->env->detach_subs)(qstate);
1329         }
1330
1331         /* Jump to the next state. */
1332         return next_state(iq, QUERYTARGETS_STATE);
1333 }
1334
1335 /**
1336  * Given a basic query, generate a parent-side "target" query.
1337  * These are subordinate queries for missing delegation point target addresses,
1338  * for which only the parent of the delegation provides correct IP addresses.
1339  *
1340  * @param qstate: query state.
1341  * @param iq: iterator query state.
1342  * @param id: module id.
1343  * @param name: target qname.
1344  * @param namelen: target qname length.
1345  * @param qtype: target qtype (either A or AAAA).
1346  * @param qclass: target qclass.
1347  * @return true on success, false on failure.
1348  */
1349 static int
1350 generate_parentside_target_query(struct module_qstate* qstate,
1351         struct iter_qstate* iq, int id, uint8_t* name, size_t namelen,
1352         uint16_t qtype, uint16_t qclass)
1353 {
1354         struct module_qstate* subq;
1355         if(!generate_sub_request(name, namelen, qtype, qclass, qstate,
1356                 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0))
1357                 return 0;
1358         if(subq) {
1359                 struct iter_qstate* subiq =
1360                         (struct iter_qstate*)subq->minfo[id];
1361                 /* blacklist the cache - we want to fetch parent stuff */
1362                 sock_list_insert(&subq->blacklist, NULL, 0, subq->region);
1363                 subiq->query_for_pside_glue = 1;
1364                 if(dname_subdomain_c(name, iq->dp->name)) {
1365                         subiq->dp = delegpt_copy(iq->dp, subq->region);
1366                         subiq->dnssec_expected = iter_indicates_dnssec(
1367                                 qstate->env, subiq->dp, NULL,
1368                                 subq->qinfo.qclass);
1369                         subiq->refetch_glue = 1;
1370                 } else {
1371                         subiq->dp = dns_cache_find_delegation(qstate->env,
1372                                 name, namelen, qtype, qclass, subq->region,
1373                                 &subiq->deleg_msg,
1374                                 *qstate->env->now+subq->prefetch_leeway);
1375                         /* if no dp, then it's from root, refetch unneeded */
1376                         if(subiq->dp) {
1377                                 subiq->dnssec_expected = iter_indicates_dnssec(
1378                                         qstate->env, subiq->dp, NULL,
1379                                         subq->qinfo.qclass);
1380                                 subiq->refetch_glue = 1;
1381                         }
1382                 }
1383         }
1384         log_nametypeclass(VERB_QUERY, "new pside target", name, qtype, qclass);
1385         return 1;
1386 }
1387
1388 /**
1389  * Given a basic query, generate a "target" query. These are subordinate
1390  * queries for missing delegation point target addresses.
1391  *
1392  * @param qstate: query state.
1393  * @param iq: iterator query state.
1394  * @param id: module id.
1395  * @param name: target qname.
1396  * @param namelen: target qname length.
1397  * @param qtype: target qtype (either A or AAAA).
1398  * @param qclass: target qclass.
1399  * @return true on success, false on failure.
1400  */
1401 static int
1402 generate_target_query(struct module_qstate* qstate, struct iter_qstate* iq,
1403         int id, uint8_t* name, size_t namelen, uint16_t qtype, uint16_t qclass)
1404 {
1405         struct module_qstate* subq;
1406         if(!generate_sub_request(name, namelen, qtype, qclass, qstate,
1407                 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0))
1408                 return 0;
1409         log_nametypeclass(VERB_QUERY, "new target", name, qtype, qclass);
1410         return 1;
1411 }
1412
1413 /**
1414  * Given an event at a certain state, generate zero or more target queries
1415  * for it's current delegation point.
1416  *
1417  * @param qstate: query state.
1418  * @param iq: iterator query state.
1419  * @param ie: iterator shared global environment.
1420  * @param id: module id.
1421  * @param maxtargets: The maximum number of targets to query for.
1422  *      if it is negative, there is no maximum number of targets.
1423  * @param num: returns the number of queries generated and processed,
1424  *      which may be zero if there were no missing targets.
1425  * @return false on error.
1426  */
1427 static int
1428 query_for_targets(struct module_qstate* qstate, struct iter_qstate* iq,
1429         struct iter_env* ie, int id, int maxtargets, int* num)
1430 {
1431         int query_count = 0;
1432         struct delegpt_ns* ns;
1433         int missing;
1434         int toget = 0;
1435
1436         if(iq->depth == ie->max_dependency_depth)
1437                 return 0;
1438         if(iq->depth > 0 && iq->target_count &&
1439                 iq->target_count[1] > MAX_TARGET_COUNT) {
1440                 char s[LDNS_MAX_DOMAINLEN+1];
1441                 dname_str(qstate->qinfo.qname, s);
1442                 verbose(VERB_QUERY, "request %s has exceeded the maximum "
1443                         "number of glue fetches %d", s, iq->target_count[1]);
1444                 return 0;
1445         }
1446
1447         iter_mark_cycle_targets(qstate, iq->dp);
1448         missing = (int)delegpt_count_missing_targets(iq->dp);
1449         log_assert(maxtargets != 0); /* that would not be useful */
1450
1451         /* Generate target requests. Basically, any missing targets
1452          * are queried for here, regardless if it is necessary to do
1453          * so to continue processing. */
1454         if(maxtargets < 0 || maxtargets > missing)
1455                 toget = missing;
1456         else    toget = maxtargets;
1457         if(toget == 0) {
1458                 *num = 0;
1459                 return 1;
1460         }
1461         /* select 'toget' items from the total of 'missing' items */
1462         log_assert(toget <= missing);
1463
1464         /* loop over missing targets */
1465         for(ns = iq->dp->nslist; ns; ns = ns->next) {
1466                 if(ns->resolved)
1467                         continue;
1468
1469                 /* randomly select this item with probability toget/missing */
1470                 if(!iter_ns_probability(qstate->env->rnd, toget, missing)) {
1471                         /* do not select this one, next; select toget number
1472                          * of items from a list one less in size */
1473                         missing --;
1474                         continue;
1475                 }
1476
1477                 if(ie->supports_ipv6 && !ns->got6) {
1478                         /* Send the AAAA request. */
1479                         if(!generate_target_query(qstate, iq, id,
1480                                 ns->name, ns->namelen,
1481                                 LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) {
1482                                 *num = query_count;
1483                                 if(query_count > 0)
1484                                         qstate->ext_state[id] = module_wait_subquery;
1485                                 return 0;
1486                         }
1487                         query_count++;
1488                 }
1489                 /* Send the A request. */
1490                 if(ie->supports_ipv4 && !ns->got4) {
1491                         if(!generate_target_query(qstate, iq, id,
1492                                 ns->name, ns->namelen,
1493                                 LDNS_RR_TYPE_A, iq->qchase.qclass)) {
1494                                 *num = query_count;
1495                                 if(query_count > 0)
1496                                         qstate->ext_state[id] = module_wait_subquery;
1497                                 return 0;
1498                         }
1499                         query_count++;
1500                 }
1501
1502                 /* mark this target as in progress. */
1503                 ns->resolved = 1;
1504                 missing--;
1505                 toget--;
1506                 if(toget == 0)
1507                         break;
1508         }
1509         *num = query_count;
1510         if(query_count > 0)
1511                 qstate->ext_state[id] = module_wait_subquery;
1512
1513         return 1;
1514 }
1515
1516 /** see if last resort is possible - does config allow queries to parent */
1517 static int
1518 can_have_last_resort(struct module_env* env, struct delegpt* dp,
1519         struct iter_qstate* iq)
1520 {
1521         struct delegpt* fwddp;
1522         struct iter_hints_stub* stub;
1523         /* do not process a last resort (the parent side) if a stub
1524          * or forward is configured, because we do not want to go 'above'
1525          * the configured servers */
1526         if(!dname_is_root(dp->name) && (stub = (struct iter_hints_stub*)
1527                 name_tree_find(&env->hints->tree, dp->name, dp->namelen,
1528                 dp->namelabs, iq->qchase.qclass)) &&
1529                 /* has_parent side is turned off for stub_first, where we
1530                  * are allowed to go to the parent */
1531                 stub->dp->has_parent_side_NS) {
1532                 verbose(VERB_QUERY, "configured stub servers failed -- returning SERVFAIL");
1533                 return 0;
1534         }
1535         if((fwddp = forwards_find(env->fwds, dp->name, iq->qchase.qclass)) &&
1536                 /* has_parent_side is turned off for forward_first, where
1537                  * we are allowed to go to the parent */
1538                 fwddp->has_parent_side_NS) {
1539                 verbose(VERB_QUERY, "configured forward servers failed -- returning SERVFAIL");
1540                 return 0;
1541         }
1542         return 1;
1543 }
1544
1545 /**
1546  * Called by processQueryTargets when it would like extra targets to query
1547  * but it seems to be out of options.  At last resort some less appealing
1548  * options are explored.  If there are no more options, the result is SERVFAIL
1549  *
1550  * @param qstate: query state.
1551  * @param iq: iterator query state.
1552  * @param ie: iterator shared global environment.
1553  * @param id: module id.
1554  * @return true if the event requires more request processing immediately,
1555  *         false if not.
1556  */
1557 static int
1558 processLastResort(struct module_qstate* qstate, struct iter_qstate* iq,
1559         struct iter_env* ie, int id)
1560 {
1561         struct delegpt_ns* ns;
1562         int query_count = 0;
1563         verbose(VERB_ALGO, "No more query targets, attempting last resort");
1564         log_assert(iq->dp);
1565
1566         if(!can_have_last_resort(qstate->env, iq->dp, iq)) {
1567                 /* fail -- no more targets, no more hope of targets, no hope
1568                  * of a response. */
1569                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1570         }
1571         if(!iq->dp->has_parent_side_NS && dname_is_root(iq->dp->name)) {
1572                 struct delegpt* p = hints_lookup_root(qstate->env->hints,
1573                         iq->qchase.qclass);
1574                 if(p) {
1575                         struct delegpt_ns* ns;
1576                         struct delegpt_addr* a;
1577                         iq->chase_flags &= ~BIT_RD; /* go to authorities */
1578                         for(ns = p->nslist; ns; ns=ns->next) {
1579                                 (void)delegpt_add_ns(iq->dp, qstate->region,
1580                                         ns->name, ns->lame);
1581                         }
1582                         for(a = p->target_list; a; a=a->next_target) {
1583                                 (void)delegpt_add_addr(iq->dp, qstate->region,
1584                                         &a->addr, a->addrlen, a->bogus,
1585                                         a->lame);
1586                         }
1587                 }
1588                 iq->dp->has_parent_side_NS = 1;
1589         } else if(!iq->dp->has_parent_side_NS) {
1590                 if(!iter_lookup_parent_NS_from_cache(qstate->env, iq->dp,
1591                         qstate->region, &qstate->qinfo)
1592                         || !iq->dp->has_parent_side_NS) {
1593                         /* if: malloc failure in lookup go up to try */
1594                         /* if: no parent NS in cache - go up one level */
1595                         verbose(VERB_ALGO, "try to grab parent NS");
1596                         iq->store_parent_NS = iq->dp;
1597                         iq->chase_flags &= ~BIT_RD; /* go to authorities */
1598                         iq->deleg_msg = NULL;
1599                         iq->refetch_glue = 1;
1600                         iq->query_restart_count++;
1601                         iq->sent_count = 0;
1602                         return next_state(iq, INIT_REQUEST_STATE);
1603                 }
1604         }
1605         /* see if that makes new names available */
1606         if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
1607                 qstate->region, iq->dp))
1608                 log_err("out of memory in cache_fill_missing");
1609         if(iq->dp->usable_list) {
1610                 verbose(VERB_ALGO, "try parent-side-name, w. glue from cache");
1611                 return next_state(iq, QUERYTARGETS_STATE);
1612         }
1613         /* try to fill out parent glue from cache */
1614         if(iter_lookup_parent_glue_from_cache(qstate->env, iq->dp,
1615                 qstate->region, &qstate->qinfo)) {
1616                 /* got parent stuff from cache, see if we can continue */
1617                 verbose(VERB_ALGO, "try parent-side glue from cache");
1618                 return next_state(iq, QUERYTARGETS_STATE);
1619         }
1620         /* query for an extra name added by the parent-NS record */
1621         if(delegpt_count_missing_targets(iq->dp) > 0) {
1622                 int qs = 0;
1623                 verbose(VERB_ALGO, "try parent-side target name");
1624                 if(!query_for_targets(qstate, iq, ie, id, 1, &qs)) {
1625                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1626                 }
1627                 iq->num_target_queries += qs;
1628                 target_count_increase(iq, qs);
1629                 if(qs != 0) {
1630                         qstate->ext_state[id] = module_wait_subquery;
1631                         return 0; /* and wait for them */
1632                 }
1633         }
1634         if(iq->depth == ie->max_dependency_depth) {
1635                 verbose(VERB_QUERY, "maxdepth and need more nameservers, fail");
1636                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1637         }
1638         if(iq->depth > 0 && iq->target_count &&
1639                 iq->target_count[1] > MAX_TARGET_COUNT) {
1640                 char s[LDNS_MAX_DOMAINLEN+1];
1641                 dname_str(qstate->qinfo.qname, s);
1642                 verbose(VERB_QUERY, "request %s has exceeded the maximum "
1643                         "number of glue fetches %d", s, iq->target_count[1]);
1644                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1645         }
1646         /* mark cycle targets for parent-side lookups */
1647         iter_mark_pside_cycle_targets(qstate, iq->dp);
1648         /* see if we can issue queries to get nameserver addresses */
1649         /* this lookup is not randomized, but sequential. */
1650         for(ns = iq->dp->nslist; ns; ns = ns->next) {
1651                 /* query for parent-side A and AAAA for nameservers */
1652                 if(ie->supports_ipv6 && !ns->done_pside6) {
1653                         /* Send the AAAA request. */
1654                         if(!generate_parentside_target_query(qstate, iq, id,
1655                                 ns->name, ns->namelen,
1656                                 LDNS_RR_TYPE_AAAA, iq->qchase.qclass))
1657                                 return error_response(qstate, id,
1658                                         LDNS_RCODE_SERVFAIL);
1659                         ns->done_pside6 = 1;
1660                         query_count++;
1661                 }
1662                 if(ie->supports_ipv4 && !ns->done_pside4) {
1663                         /* Send the A request. */
1664                         if(!generate_parentside_target_query(qstate, iq, id,
1665                                 ns->name, ns->namelen,
1666                                 LDNS_RR_TYPE_A, iq->qchase.qclass))
1667                                 return error_response(qstate, id,
1668                                         LDNS_RCODE_SERVFAIL);
1669                         ns->done_pside4 = 1;
1670                         query_count++;
1671                 }
1672                 if(query_count != 0) { /* suspend to await results */
1673                         verbose(VERB_ALGO, "try parent-side glue lookup");
1674                         iq->num_target_queries += query_count;
1675                         target_count_increase(iq, query_count);
1676                         qstate->ext_state[id] = module_wait_subquery;
1677                         return 0;
1678                 }
1679         }
1680
1681         /* if this was a parent-side glue query itself, then store that
1682          * failure in cache. */
1683         if(iq->query_for_pside_glue && !iq->pside_glue)
1684                 iter_store_parentside_neg(qstate->env, &qstate->qinfo,
1685                         iq->deleg_msg?iq->deleg_msg->rep:
1686                         (iq->response?iq->response->rep:NULL));
1687
1688         verbose(VERB_QUERY, "out of query targets -- returning SERVFAIL");
1689         /* fail -- no more targets, no more hope of targets, no hope
1690          * of a response. */
1691         return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1692 }
1693
1694 /**
1695  * Try to find the NS record set that will resolve a qtype DS query. Due
1696  * to grandparent/grandchild reasons we did not get a proper lookup right
1697  * away.  We need to create type NS queries until we get the right parent
1698  * for this lookup.  We remove labels from the query to find the right point.
1699  * If we end up at the old dp name, then there is no solution.
1700  *
1701  * @param qstate: query state.
1702  * @param iq: iterator query state.
1703  * @param id: module id.
1704  * @return true if the event requires more immediate processing, false if
1705  *         not. This is generally only true when forwarding the request to
1706  *         the final state (i.e., on answer).
1707  */
1708 static int
1709 processDSNSFind(struct module_qstate* qstate, struct iter_qstate* iq, int id)
1710 {
1711         struct module_qstate* subq = NULL;
1712         verbose(VERB_ALGO, "processDSNSFind");
1713
1714         if(!iq->dsns_point) {
1715                 /* initialize */
1716                 iq->dsns_point = iq->qchase.qname;
1717                 iq->dsns_point_len = iq->qchase.qname_len;
1718         }
1719         /* robustcheck for internal error: we are not underneath the dp */
1720         if(!dname_subdomain_c(iq->dsns_point, iq->dp->name)) {
1721                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1722         }
1723
1724         /* go up one (more) step, until we hit the dp, if so, end */
1725         dname_remove_label(&iq->dsns_point, &iq->dsns_point_len);
1726         if(query_dname_compare(iq->dsns_point, iq->dp->name) == 0) {
1727                 /* there was no inbetween nameserver, use the old delegation
1728                  * point again.  And this time, because dsns_point is nonNULL
1729                  * we are going to accept the (bad) result */
1730                 iq->state = QUERYTARGETS_STATE;
1731                 return 1;
1732         }
1733         iq->state = DSNS_FIND_STATE;
1734
1735         /* spawn NS lookup (validation not needed, this is for DS lookup) */
1736         log_nametypeclass(VERB_ALGO, "fetch nameservers",
1737                 iq->dsns_point, LDNS_RR_TYPE_NS, iq->qchase.qclass);
1738         if(!generate_sub_request(iq->dsns_point, iq->dsns_point_len,
1739                 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
1740                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0)) {
1741                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1742         }
1743
1744         return 0;
1745 }
1746
1747 /**
1748  * This is the request event state where the request will be sent to one of
1749  * its current query targets. This state also handles issuing target lookup
1750  * queries for missing target IP addresses. Queries typically iterate on
1751  * this state, both when they are just trying different targets for a given
1752  * delegation point, and when they change delegation points. This state
1753  * roughly corresponds to RFC 1034 algorithm steps 3 and 4.
1754  *
1755  * @param qstate: query state.
1756  * @param iq: iterator query state.
1757  * @param ie: iterator shared global environment.
1758  * @param id: module id.
1759  * @return true if the event requires more request processing immediately,
1760  *         false if not. This state only returns true when it is generating
1761  *         a SERVFAIL response because the query has hit a dead end.
1762  */
1763 static int
1764 processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
1765         struct iter_env* ie, int id)
1766 {
1767         int tf_policy;
1768         struct delegpt_addr* target;
1769         struct outbound_entry* outq;
1770
1771         /* NOTE: a request will encounter this state for each target it
1772          * needs to send a query to. That is, at least one per referral,
1773          * more if some targets timeout or return throwaway answers. */
1774
1775         log_query_info(VERB_QUERY, "processQueryTargets:", &qstate->qinfo);
1776         verbose(VERB_ALGO, "processQueryTargets: targetqueries %d, "
1777                 "currentqueries %d sentcount %d", iq->num_target_queries,
1778                 iq->num_current_queries, iq->sent_count);
1779
1780         /* Make sure that we haven't run away */
1781         /* FIXME: is this check even necessary? */
1782         if(iq->referral_count > MAX_REFERRAL_COUNT) {
1783                 verbose(VERB_QUERY, "request has exceeded the maximum "
1784                         "number of referrrals with %d", iq->referral_count);
1785                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1786         }
1787         if(iq->sent_count > MAX_SENT_COUNT) {
1788                 verbose(VERB_QUERY, "request has exceeded the maximum "
1789                         "number of sends with %d", iq->sent_count);
1790                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1791         }
1792
1793         /* Make sure we have a delegation point, otherwise priming failed
1794          * or another failure occurred */
1795         if(!iq->dp) {
1796                 verbose(VERB_QUERY, "Failed to get a delegation, giving up");
1797                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1798         }
1799         if(!ie->supports_ipv6)
1800                 delegpt_no_ipv6(iq->dp);
1801         if(!ie->supports_ipv4)
1802                 delegpt_no_ipv4(iq->dp);
1803         delegpt_log(VERB_ALGO, iq->dp);
1804
1805         if(iq->num_current_queries>0) {
1806                 /* already busy answering a query, this restart is because
1807                  * more delegpt addrs became available, wait for existing
1808                  * query. */
1809                 verbose(VERB_ALGO, "woke up, but wait for outstanding query");
1810                 qstate->ext_state[id] = module_wait_reply;
1811                 return 0;
1812         }
1813
1814         tf_policy = 0;
1815         /* < not <=, because although the array is large enough for <=, the
1816          * generated query will immediately be discarded due to depth and
1817          * that servfail is cached, which is not good as opportunism goes. */
1818         if(iq->depth < ie->max_dependency_depth
1819                 && iq->sent_count < TARGET_FETCH_STOP) {
1820                 tf_policy = ie->target_fetch_policy[iq->depth];
1821         }
1822
1823         /* if in 0x20 fallback get as many targets as possible */
1824         if(iq->caps_fallback) {
1825                 int extra = 0;
1826                 size_t naddr, nres, navail;
1827                 if(!query_for_targets(qstate, iq, ie, id, -1, &extra)) {
1828                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1829                 }
1830                 iq->num_target_queries += extra;
1831                 target_count_increase(iq, extra);
1832                 if(iq->num_target_queries > 0) {
1833                         /* wait to get all targets, we want to try em */
1834                         verbose(VERB_ALGO, "wait for all targets for fallback");
1835                         qstate->ext_state[id] = module_wait_reply;
1836                         return 0;
1837                 }
1838                 /* did we do enough fallback queries already? */
1839                 delegpt_count_addr(iq->dp, &naddr, &nres, &navail);
1840                 /* the current caps_server is the number of fallbacks sent.
1841                  * the original query is one that matched too, so we have
1842                  * caps_server+1 number of matching queries now */
1843                 if(iq->caps_server+1 >= naddr*3 ||
1844                         iq->caps_server*2+2 >= MAX_SENT_COUNT) {
1845                         /* *2 on sentcount check because ipv6 may fail */
1846                         /* we're done, process the response */
1847                         verbose(VERB_ALGO, "0x20 fallback had %d responses "
1848                                 "match for %d wanted, done.",
1849                                 (int)iq->caps_server+1, (int)naddr*3);
1850                         iq->response = iq->caps_response;
1851                         iq->caps_fallback = 0;
1852                         iter_dec_attempts(iq->dp, 3); /* space for fallback */
1853                         iq->num_current_queries++; /* RespState decrements it*/
1854                         iq->referral_count++; /* make sure we don't loop */
1855                         iq->sent_count = 0;
1856                         iq->state = QUERY_RESP_STATE;
1857                         return 1;
1858                 }
1859                 verbose(VERB_ALGO, "0x20 fallback number %d",
1860                         (int)iq->caps_server);
1861
1862         /* if there is a policy to fetch missing targets
1863          * opportunistically, do it. we rely on the fact that once a
1864          * query (or queries) for a missing name have been issued,
1865          * they will not show up again. */
1866         } else if(tf_policy != 0) {
1867                 int extra = 0;
1868                 verbose(VERB_ALGO, "attempt to get extra %d targets",
1869                         tf_policy);
1870                 (void)query_for_targets(qstate, iq, ie, id, tf_policy, &extra);
1871                 /* errors ignored, these targets are not strictly necessary for
1872                  * this result, we do not have to reply with SERVFAIL */
1873                 iq->num_target_queries += extra;
1874                 target_count_increase(iq, extra);
1875         }
1876
1877         /* Add the current set of unused targets to our queue. */
1878         delegpt_add_unused_targets(iq->dp);
1879
1880         /* Select the next usable target, filtering out unsuitable targets. */
1881         target = iter_server_selection(ie, qstate->env, iq->dp,
1882                 iq->dp->name, iq->dp->namelen, iq->qchase.qtype,
1883                 &iq->dnssec_lame_query, &iq->chase_to_rd,
1884                 iq->num_target_queries, qstate->blacklist);
1885
1886         /* If no usable target was selected... */
1887         if(!target) {
1888                 /* Here we distinguish between three states: generate a new
1889                  * target query, just wait, or quit (with a SERVFAIL).
1890                  * We have the following information: number of active
1891                  * target queries, number of active current queries,
1892                  * the presence of missing targets at this delegation
1893                  * point, and the given query target policy. */
1894
1895                 /* Check for the wait condition. If this is true, then
1896                  * an action must be taken. */
1897                 if(iq->num_target_queries==0 && iq->num_current_queries==0) {
1898                         /* If there is nothing to wait for, then we need
1899                          * to distinguish between generating (a) new target
1900                          * query, or failing. */
1901                         if(delegpt_count_missing_targets(iq->dp) > 0) {
1902                                 int qs = 0;
1903                                 verbose(VERB_ALGO, "querying for next "
1904                                         "missing target");
1905                                 if(!query_for_targets(qstate, iq, ie, id,
1906                                         1, &qs)) {
1907                                         return error_response(qstate, id,
1908                                                 LDNS_RCODE_SERVFAIL);
1909                                 }
1910                                 if(qs == 0 &&
1911                                    delegpt_count_missing_targets(iq->dp) == 0){
1912                                         /* it looked like there were missing
1913                                          * targets, but they did not turn up.
1914                                          * Try the bad choices again (if any),
1915                                          * when we get back here missing==0,
1916                                          * so this is not a loop. */
1917                                         return 1;
1918                                 }
1919                                 iq->num_target_queries += qs;
1920                                 target_count_increase(iq, qs);
1921                         }
1922                         /* Since a target query might have been made, we
1923                          * need to check again. */
1924                         if(iq->num_target_queries == 0) {
1925                                 /* if in capsforid fallback, instead of last
1926                                  * resort, we agree with the current reply
1927                                  * we have (if any) (our count of addrs bad)*/
1928                                 if(iq->caps_fallback && iq->caps_reply) {
1929                                         /* we're done, process the response */
1930                                         verbose(VERB_ALGO, "0x20 fallback had %d responses, "
1931                                                 "but no more servers except "
1932                                                 "last resort, done.",
1933                                                 (int)iq->caps_server+1);
1934                                         iq->response = iq->caps_response;
1935                                         iq->caps_fallback = 0;
1936                                         iter_dec_attempts(iq->dp, 3); /* space for fallback */
1937                                         iq->num_current_queries++; /* RespState decrements it*/
1938                                         iq->referral_count++; /* make sure we don't loop */
1939                                         iq->sent_count = 0;
1940                                         iq->state = QUERY_RESP_STATE;
1941                                         return 1;
1942                                 }
1943                                 return processLastResort(qstate, iq, ie, id);
1944                         }
1945                 }
1946
1947                 /* otherwise, we have no current targets, so submerge
1948                  * until one of the target or direct queries return. */
1949                 if(iq->num_target_queries>0 && iq->num_current_queries>0) {
1950                         verbose(VERB_ALGO, "no current targets -- waiting "
1951                                 "for %d targets to resolve or %d outstanding"
1952                                 " queries to respond", iq->num_target_queries,
1953                                 iq->num_current_queries);
1954                         qstate->ext_state[id] = module_wait_reply;
1955                 } else if(iq->num_target_queries>0) {
1956                         verbose(VERB_ALGO, "no current targets -- waiting "
1957                                 "for %d targets to resolve.",
1958                                 iq->num_target_queries);
1959                         qstate->ext_state[id] = module_wait_subquery;
1960                 } else {
1961                         verbose(VERB_ALGO, "no current targets -- waiting "
1962                                 "for %d outstanding queries to respond.",
1963                                 iq->num_current_queries);
1964                         qstate->ext_state[id] = module_wait_reply;
1965                 }
1966                 return 0;
1967         }
1968
1969         /* if not forwarding, check ratelimits per delegationpoint name */
1970         if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok) {
1971                 if(!infra_ratelimit_inc(qstate->env->infra_cache, iq->dp->name,
1972                         iq->dp->namelen, *qstate->env->now)) {
1973                         verbose(VERB_ALGO, "query exceeded ratelimits");
1974                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1975                 }
1976         }
1977
1978         /* We have a valid target. */
1979         if(verbosity >= VERB_QUERY) {
1980                 log_query_info(VERB_QUERY, "sending query:", &iq->qchase);
1981                 log_name_addr(VERB_QUERY, "sending to target:", iq->dp->name,
1982                         &target->addr, target->addrlen);
1983                 verbose(VERB_ALGO, "dnssec status: %s%s",
1984                         iq->dnssec_expected?"expected": "not expected",
1985                         iq->dnssec_lame_query?" but lame_query anyway": "");
1986         }
1987         fptr_ok(fptr_whitelist_modenv_send_query(qstate->env->send_query));
1988         outq = (*qstate->env->send_query)(
1989                 iq->qchase.qname, iq->qchase.qname_len,
1990                 iq->qchase.qtype, iq->qchase.qclass,
1991                 iq->chase_flags | (iq->chase_to_rd?BIT_RD:0), EDNS_DO|BIT_CD,
1992                 iq->dnssec_expected, iq->caps_fallback || is_caps_whitelisted(
1993                 ie, iq), &target->addr, target->addrlen, iq->dp->name,
1994                 iq->dp->namelen, qstate);
1995         if(!outq) {
1996                 log_addr(VERB_DETAIL, "error sending query to auth server",
1997                         &target->addr, target->addrlen);
1998                 if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok)
1999                     infra_ratelimit_dec(qstate->env->infra_cache, iq->dp->name,
2000                         iq->dp->namelen, *qstate->env->now);
2001                 return next_state(iq, QUERYTARGETS_STATE);
2002         }
2003         outbound_list_insert(&iq->outlist, outq);
2004         iq->num_current_queries++;
2005         iq->sent_count++;
2006         qstate->ext_state[id] = module_wait_reply;
2007
2008         return 0;
2009 }
2010
2011 /** find NS rrset in given list */
2012 static struct ub_packed_rrset_key*
2013 find_NS(struct reply_info* rep, size_t from, size_t to)
2014 {
2015         size_t i;
2016         for(i=from; i<to; i++) {
2017                 if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NS)
2018                         return rep->rrsets[i];
2019         }
2020         return NULL;
2021 }
2022
2023
2024 /**
2025  * Process the query response. All queries end up at this state first. This
2026  * process generally consists of analyzing the response and routing the
2027  * event to the next state (either bouncing it back to a request state, or
2028  * terminating the processing for this event).
2029  *
2030  * @param qstate: query state.
2031  * @param iq: iterator query state.
2032  * @param id: module id.
2033  * @return true if the event requires more immediate processing, false if
2034  *         not. This is generally only true when forwarding the request to
2035  *         the final state (i.e., on answer).
2036  */
2037 static int
2038 processQueryResponse(struct module_qstate* qstate, struct iter_qstate* iq,
2039         int id)
2040 {
2041         int dnsseclame = 0;
2042         enum response_type type;
2043         iq->num_current_queries--;
2044         if(iq->response == NULL) {
2045                 iq->chase_to_rd = 0;
2046                 iq->dnssec_lame_query = 0;
2047                 verbose(VERB_ALGO, "query response was timeout");
2048                 return next_state(iq, QUERYTARGETS_STATE);
2049         }
2050         type = response_type_from_server(
2051                 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd),
2052                 iq->response, &iq->qchase, iq->dp);
2053         iq->chase_to_rd = 0;
2054         if(type == RESPONSE_TYPE_REFERRAL && (iq->chase_flags&BIT_RD)) {
2055                 /* When forwarding (RD bit is set), we handle referrals
2056                  * differently. No queries should be sent elsewhere */
2057                 type = RESPONSE_TYPE_ANSWER;
2058         }
2059         if(iq->dnssec_expected && !iq->dnssec_lame_query &&
2060                 !(iq->chase_flags&BIT_RD)
2061                 && type != RESPONSE_TYPE_LAME
2062                 && type != RESPONSE_TYPE_REC_LAME
2063                 && type != RESPONSE_TYPE_THROWAWAY
2064                 && type != RESPONSE_TYPE_UNTYPED) {
2065                 /* a possible answer, see if it is missing DNSSEC */
2066                 /* but not when forwarding, so we dont mark fwder lame */
2067                 if(!iter_msg_has_dnssec(iq->response)) {
2068                         /* Mark this address as dnsseclame in this dp,
2069                          * because that will make serverselection disprefer
2070                          * it, but also, once it is the only final option,
2071                          * use dnssec-lame-bypass if it needs to query there.*/
2072                         if(qstate->reply) {
2073                                 struct delegpt_addr* a = delegpt_find_addr(
2074                                         iq->dp, &qstate->reply->addr,
2075                                         qstate->reply->addrlen);
2076                                 if(a) a->dnsseclame = 1;
2077                         }
2078                         /* test the answer is from the zone we expected,
2079                          * otherwise, (due to parent,child on same server), we
2080                          * might mark the server,zone lame inappropriately */
2081                         if(!iter_msg_from_zone(iq->response, iq->dp, type,
2082                                 iq->qchase.qclass))
2083                                 qstate->reply = NULL;
2084                         type = RESPONSE_TYPE_LAME;
2085                         dnsseclame = 1;
2086                 }
2087         } else iq->dnssec_lame_query = 0;
2088         /* see if referral brings us close to the target */
2089         if(type == RESPONSE_TYPE_REFERRAL) {
2090                 struct ub_packed_rrset_key* ns = find_NS(
2091                         iq->response->rep, iq->response->rep->an_numrrsets,
2092                         iq->response->rep->an_numrrsets
2093                         + iq->response->rep->ns_numrrsets);
2094                 if(!ns) ns = find_NS(iq->response->rep, 0,
2095                                 iq->response->rep->an_numrrsets);
2096                 if(!ns || !dname_strict_subdomain_c(ns->rk.dname, iq->dp->name)
2097                         || !dname_subdomain_c(iq->qchase.qname, ns->rk.dname)){
2098                         verbose(VERB_ALGO, "bad referral, throwaway");
2099                         type = RESPONSE_TYPE_THROWAWAY;
2100                 } else
2101                         iter_scrub_ds(iq->response, ns, iq->dp->name);
2102         } else iter_scrub_ds(iq->response, NULL, NULL);
2103
2104         /* handle each of the type cases */
2105         if(type == RESPONSE_TYPE_ANSWER) {
2106                 /* ANSWER type responses terminate the query algorithm,
2107                  * so they sent on their */
2108                 if(verbosity >= VERB_DETAIL) {
2109                         verbose(VERB_DETAIL, "query response was %s",
2110                                 FLAGS_GET_RCODE(iq->response->rep->flags)
2111                                 ==LDNS_RCODE_NXDOMAIN?"NXDOMAIN ANSWER":
2112                                 (iq->response->rep->an_numrrsets?"ANSWER":
2113                                 "nodata ANSWER"));
2114                 }
2115                 /* if qtype is DS, check we have the right level of answer,
2116                  * like grandchild answer but we need the middle, reject it */
2117                 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
2118                         && !(iq->chase_flags&BIT_RD)
2119                         && iter_ds_toolow(iq->response, iq->dp)
2120                         && iter_dp_cangodown(&iq->qchase, iq->dp)) {
2121                         /* close down outstanding requests to be discarded */
2122                         outbound_list_clear(&iq->outlist);
2123                         iq->num_current_queries = 0;
2124                         fptr_ok(fptr_whitelist_modenv_detach_subs(
2125                                 qstate->env->detach_subs));
2126                         (*qstate->env->detach_subs)(qstate);
2127                         iq->num_target_queries = 0;
2128                         return processDSNSFind(qstate, iq, id);
2129                 }
2130                 iter_dns_store(qstate->env, &iq->response->qinfo,
2131                         iq->response->rep, 0, qstate->prefetch_leeway,
2132                         iq->dp&&iq->dp->has_parent_side_NS,
2133                         qstate->region, qstate->query_flags);
2134                 /* close down outstanding requests to be discarded */
2135                 outbound_list_clear(&iq->outlist);
2136                 iq->num_current_queries = 0;
2137                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2138                         qstate->env->detach_subs));
2139                 (*qstate->env->detach_subs)(qstate);
2140                 iq->num_target_queries = 0;
2141                 if(qstate->reply)
2142                         sock_list_insert(&qstate->reply_origin,
2143                                 &qstate->reply->addr, qstate->reply->addrlen,
2144                                 qstate->region);
2145                 return final_state(iq);
2146         } else if(type == RESPONSE_TYPE_REFERRAL) {
2147                 /* REFERRAL type responses get a reset of the
2148                  * delegation point, and back to the QUERYTARGETS_STATE. */
2149                 verbose(VERB_DETAIL, "query response was REFERRAL");
2150
2151                 if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok) {
2152                         /* we have a referral, no ratelimit, we can send
2153                          * our queries to the given name */
2154                         infra_ratelimit_dec(qstate->env->infra_cache,
2155                                 iq->dp->name, iq->dp->namelen,
2156                                 *qstate->env->now);
2157                 }
2158
2159                 /* if hardened, only store referral if we asked for it */
2160                 if(!qstate->env->cfg->harden_referral_path ||
2161                     (  qstate->qinfo.qtype == LDNS_RR_TYPE_NS
2162                         && (qstate->query_flags&BIT_RD)
2163                         && !(qstate->query_flags&BIT_CD)
2164                            /* we know that all other NS rrsets are scrubbed
2165                             * away, thus on referral only one is left.
2166                             * see if that equals the query name... */
2167                         && ( /* auth section, but sometimes in answer section*/
2168                           reply_find_rrset_section_ns(iq->response->rep,
2169                                 iq->qchase.qname, iq->qchase.qname_len,
2170                                 LDNS_RR_TYPE_NS, iq->qchase.qclass)
2171                           || reply_find_rrset_section_an(iq->response->rep,
2172                                 iq->qchase.qname, iq->qchase.qname_len,
2173                                 LDNS_RR_TYPE_NS, iq->qchase.qclass)
2174                           )
2175                     )) {
2176                         /* Store the referral under the current query */
2177                         /* no prefetch-leeway, since its not the answer */
2178                         iter_dns_store(qstate->env, &iq->response->qinfo,
2179                                 iq->response->rep, 1, 0, 0, NULL, 0);
2180                         if(iq->store_parent_NS)
2181                                 iter_store_parentside_NS(qstate->env,
2182                                         iq->response->rep);
2183                         if(qstate->env->neg_cache)
2184                                 val_neg_addreferral(qstate->env->neg_cache,
2185                                         iq->response->rep, iq->dp->name);
2186                 }
2187                 /* store parent-side-in-zone-glue, if directly queried for */
2188                 if(iq->query_for_pside_glue && !iq->pside_glue) {
2189                         iq->pside_glue = reply_find_rrset(iq->response->rep,
2190                                 iq->qchase.qname, iq->qchase.qname_len,
2191                                 iq->qchase.qtype, iq->qchase.qclass);
2192                         if(iq->pside_glue) {
2193                                 log_rrset_key(VERB_ALGO, "found parent-side "
2194                                         "glue", iq->pside_glue);
2195                                 iter_store_parentside_rrset(qstate->env,
2196                                         iq->pside_glue);
2197                         }
2198                 }
2199
2200                 /* Reset the event state, setting the current delegation
2201                  * point to the referral. */
2202                 iq->deleg_msg = iq->response;
2203                 iq->dp = delegpt_from_message(iq->response, qstate->region);
2204                 if(!iq->dp)
2205                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2206                 if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
2207                         qstate->region, iq->dp))
2208                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2209                 if(iq->store_parent_NS && query_dname_compare(iq->dp->name,
2210                         iq->store_parent_NS->name) == 0)
2211                         iter_merge_retry_counts(iq->dp, iq->store_parent_NS);
2212                 delegpt_log(VERB_ALGO, iq->dp);
2213                 /* Count this as a referral. */
2214                 iq->referral_count++;
2215                 iq->sent_count = 0;
2216                 /* see if the next dp is a trust anchor, or a DS was sent
2217                  * along, indicating dnssec is expected for next zone */
2218                 iq->dnssec_expected = iter_indicates_dnssec(qstate->env,
2219                         iq->dp, iq->response, iq->qchase.qclass);
2220                 /* if dnssec, validating then also fetch the key for the DS */
2221                 if(iq->dnssec_expected && qstate->env->cfg->prefetch_key &&
2222                         !(qstate->query_flags&BIT_CD))
2223                         generate_dnskey_prefetch(qstate, iq, id);
2224
2225                 /* spawn off NS and addr to auth servers for the NS we just
2226                  * got in the referral. This gets authoritative answer
2227                  * (answer section trust level) rrset.
2228                  * right after, we detach the subs, answer goes to cache. */
2229                 if(qstate->env->cfg->harden_referral_path)
2230                         generate_ns_check(qstate, iq, id);
2231
2232                 /* stop current outstanding queries.
2233                  * FIXME: should the outstanding queries be waited for and
2234                  * handled? Say by a subquery that inherits the outbound_entry.
2235                  */
2236                 outbound_list_clear(&iq->outlist);
2237                 iq->num_current_queries = 0;
2238                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2239                         qstate->env->detach_subs));
2240                 (*qstate->env->detach_subs)(qstate);
2241                 iq->num_target_queries = 0;
2242                 verbose(VERB_ALGO, "cleared outbound list for next round");
2243                 return next_state(iq, QUERYTARGETS_STATE);
2244         } else if(type == RESPONSE_TYPE_CNAME) {
2245                 uint8_t* sname = NULL;
2246                 size_t snamelen = 0;
2247                 /* CNAME type responses get a query restart (i.e., get a
2248                  * reset of the query state and go back to INIT_REQUEST_STATE).
2249                  */
2250                 verbose(VERB_DETAIL, "query response was CNAME");
2251                 if(verbosity >= VERB_ALGO)
2252                         log_dns_msg("cname msg", &iq->response->qinfo,
2253                                 iq->response->rep);
2254                 /* if qtype is DS, check we have the right level of answer,
2255                  * like grandchild answer but we need the middle, reject it */
2256                 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
2257                         && !(iq->chase_flags&BIT_RD)
2258                         && iter_ds_toolow(iq->response, iq->dp)
2259                         && iter_dp_cangodown(&iq->qchase, iq->dp)) {
2260                         outbound_list_clear(&iq->outlist);
2261                         iq->num_current_queries = 0;
2262                         fptr_ok(fptr_whitelist_modenv_detach_subs(
2263                                 qstate->env->detach_subs));
2264                         (*qstate->env->detach_subs)(qstate);
2265                         iq->num_target_queries = 0;
2266                         return processDSNSFind(qstate, iq, id);
2267                 }
2268                 /* Process the CNAME response. */
2269                 if(!handle_cname_response(qstate, iq, iq->response,
2270                         &sname, &snamelen))
2271                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2272                 /* cache the CNAME response under the current query */
2273                 /* NOTE : set referral=1, so that rrsets get stored but not
2274                  * the partial query answer (CNAME only). */
2275                 /* prefetchleeway applied because this updates answer parts */
2276                 iter_dns_store(qstate->env, &iq->response->qinfo,
2277                         iq->response->rep, 1, qstate->prefetch_leeway,
2278                         iq->dp&&iq->dp->has_parent_side_NS, NULL,
2279                         qstate->query_flags);
2280                 /* set the current request's qname to the new value. */
2281                 iq->qchase.qname = sname;
2282                 iq->qchase.qname_len = snamelen;
2283                 /* Clear the query state, since this is a query restart. */
2284                 iq->deleg_msg = NULL;
2285                 iq->dp = NULL;
2286                 iq->dsns_point = NULL;
2287                 /* Note the query restart. */
2288                 iq->query_restart_count++;
2289                 iq->sent_count = 0;
2290
2291                 /* stop current outstanding queries.
2292                  * FIXME: should the outstanding queries be waited for and
2293                  * handled? Say by a subquery that inherits the outbound_entry.
2294                  */
2295                 outbound_list_clear(&iq->outlist);
2296                 iq->num_current_queries = 0;
2297                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2298                         qstate->env->detach_subs));
2299                 (*qstate->env->detach_subs)(qstate);
2300                 iq->num_target_queries = 0;
2301                 if(qstate->reply)
2302                         sock_list_insert(&qstate->reply_origin,
2303                                 &qstate->reply->addr, qstate->reply->addrlen,
2304                                 qstate->region);
2305                 verbose(VERB_ALGO, "cleared outbound list for query restart");
2306                 /* go to INIT_REQUEST_STATE for new qname. */
2307                 return next_state(iq, INIT_REQUEST_STATE);
2308         } else if(type == RESPONSE_TYPE_LAME) {
2309                 /* Cache the LAMEness. */
2310                 verbose(VERB_DETAIL, "query response was %sLAME",
2311                         dnsseclame?"DNSSEC ":"");
2312                 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) {
2313                         log_err("mark lame: mismatch in qname and dpname");
2314                         /* throwaway this reply below */
2315                 } else if(qstate->reply) {
2316                         /* need addr for lameness cache, but we may have
2317                          * gotten this from cache, so test to be sure */
2318                         if(!infra_set_lame(qstate->env->infra_cache,
2319                                 &qstate->reply->addr, qstate->reply->addrlen,
2320                                 iq->dp->name, iq->dp->namelen,
2321                                 *qstate->env->now, dnsseclame, 0,
2322                                 iq->qchase.qtype))
2323                                 log_err("mark host lame: out of memory");
2324                 }
2325         } else if(type == RESPONSE_TYPE_REC_LAME) {
2326                 /* Cache the LAMEness. */
2327                 verbose(VERB_DETAIL, "query response REC_LAME: "
2328                         "recursive but not authoritative server");
2329                 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) {
2330                         log_err("mark rec_lame: mismatch in qname and dpname");
2331                         /* throwaway this reply below */
2332                 } else if(qstate->reply) {
2333                         /* need addr for lameness cache, but we may have
2334                          * gotten this from cache, so test to be sure */
2335                         verbose(VERB_DETAIL, "mark as REC_LAME");
2336                         if(!infra_set_lame(qstate->env->infra_cache,
2337                                 &qstate->reply->addr, qstate->reply->addrlen,
2338                                 iq->dp->name, iq->dp->namelen,
2339                                 *qstate->env->now, 0, 1, iq->qchase.qtype))
2340                                 log_err("mark host lame: out of memory");
2341                 }
2342         } else if(type == RESPONSE_TYPE_THROWAWAY) {
2343                 /* LAME and THROWAWAY responses are handled the same way.
2344                  * In this case, the event is just sent directly back to
2345                  * the QUERYTARGETS_STATE without resetting anything,
2346                  * because, clearly, the next target must be tried. */
2347                 verbose(VERB_DETAIL, "query response was THROWAWAY");
2348         } else {
2349                 log_warn("A query response came back with an unknown type: %d",
2350                         (int)type);
2351         }
2352
2353         /* LAME, THROWAWAY and "unknown" all end up here.
2354          * Recycle to the QUERYTARGETS state to hopefully try a
2355          * different target. */
2356         return next_state(iq, QUERYTARGETS_STATE);
2357 }
2358
2359 /**
2360  * Return priming query results to interested super querystates.
2361  *
2362  * Sets the delegation point and delegation message (not nonRD queries).
2363  * This is a callback from walk_supers.
2364  *
2365  * @param qstate: priming query state that finished.
2366  * @param id: module id.
2367  * @param forq: the qstate for which priming has been done.
2368  */
2369 static void
2370 prime_supers(struct module_qstate* qstate, int id, struct module_qstate* forq)
2371 {
2372         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
2373         struct delegpt* dp = NULL;
2374
2375         log_assert(qstate->is_priming || foriq->wait_priming_stub);
2376         log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR);
2377         /* Convert our response to a delegation point */
2378         dp = delegpt_from_message(qstate->return_msg, forq->region);
2379         if(!dp) {
2380                 /* if there is no convertable delegation point, then
2381                  * the ANSWER type was (presumably) a negative answer. */
2382                 verbose(VERB_ALGO, "prime response was not a positive "
2383                         "ANSWER; failing");
2384                 foriq->dp = NULL;
2385                 foriq->state = QUERYTARGETS_STATE;
2386                 return;
2387         }
2388
2389         log_query_info(VERB_DETAIL, "priming successful for", &qstate->qinfo);
2390         delegpt_log(VERB_ALGO, dp);
2391         foriq->dp = dp;
2392         foriq->deleg_msg = dns_copy_msg(qstate->return_msg, forq->region);
2393         if(!foriq->deleg_msg) {
2394                 log_err("copy prime response: out of memory");
2395                 foriq->dp = NULL;
2396                 foriq->state = QUERYTARGETS_STATE;
2397                 return;
2398         }
2399
2400         /* root priming responses go to init stage 2, priming stub
2401          * responses to to stage 3. */
2402         if(foriq->wait_priming_stub) {
2403                 foriq->state = INIT_REQUEST_3_STATE;
2404                 foriq->wait_priming_stub = 0;
2405         } else  foriq->state = INIT_REQUEST_2_STATE;
2406         /* because we are finished, the parent will be reactivated */
2407 }
2408
2409 /**
2410  * This handles the response to a priming query. This is used to handle both
2411  * root and stub priming responses. This is basically the equivalent of the
2412  * QUERY_RESP_STATE, but will not handle CNAME responses and will treat
2413  * REFERRALs as ANSWERS. It will also update and reactivate the originating
2414  * event.
2415  *
2416  * @param qstate: query state.
2417  * @param id: module id.
2418  * @return true if the event needs more immediate processing, false if not.
2419  *         This state always returns false.
2420  */
2421 static int
2422 processPrimeResponse(struct module_qstate* qstate, int id)
2423 {
2424         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
2425         enum response_type type;
2426         iq->response->rep->flags &= ~(BIT_RD|BIT_RA); /* ignore rec-lame */
2427         type = response_type_from_server(
2428                 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd),
2429                 iq->response, &iq->qchase, iq->dp);
2430         if(type == RESPONSE_TYPE_ANSWER) {
2431                 qstate->return_rcode = LDNS_RCODE_NOERROR;
2432                 qstate->return_msg = iq->response;
2433         } else {
2434                 qstate->return_rcode = LDNS_RCODE_SERVFAIL;
2435                 qstate->return_msg = NULL;
2436         }
2437
2438         /* validate the root or stub after priming (if enabled).
2439          * This is the same query as the prime query, but with validation.
2440          * Now that we are primed, the additional queries that validation
2441          * may need can be resolved, such as DLV. */
2442         if(qstate->env->cfg->harden_referral_path) {
2443                 struct module_qstate* subq = NULL;
2444                 log_nametypeclass(VERB_ALGO, "schedule prime validation",
2445                         qstate->qinfo.qname, qstate->qinfo.qtype,
2446                         qstate->qinfo.qclass);
2447                 if(!generate_sub_request(qstate->qinfo.qname,
2448                         qstate->qinfo.qname_len, qstate->qinfo.qtype,
2449                         qstate->qinfo.qclass, qstate, id, iq,
2450                         INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) {
2451                         verbose(VERB_ALGO, "could not generate prime check");
2452                 }
2453                 generate_a_aaaa_check(qstate, iq, id);
2454         }
2455
2456         /* This event is finished. */
2457         qstate->ext_state[id] = module_finished;
2458         return 0;
2459 }
2460
2461 /**
2462  * Do final processing on responses to target queries. Events reach this
2463  * state after the iterative resolution algorithm terminates. This state is
2464  * responsible for reactiving the original event, and housekeeping related
2465  * to received target responses (caching, updating the current delegation
2466  * point, etc).
2467  * Callback from walk_supers for every super state that is interested in
2468  * the results from this query.
2469  *
2470  * @param qstate: query state.
2471  * @param id: module id.
2472  * @param forq: super query state.
2473  */
2474 static void
2475 processTargetResponse(struct module_qstate* qstate, int id,
2476         struct module_qstate* forq)
2477 {
2478         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
2479         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
2480         struct ub_packed_rrset_key* rrset;
2481         struct delegpt_ns* dpns;
2482         log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR);
2483
2484         foriq->state = QUERYTARGETS_STATE;
2485         log_query_info(VERB_ALGO, "processTargetResponse", &qstate->qinfo);
2486         log_query_info(VERB_ALGO, "processTargetResponse super", &forq->qinfo);
2487
2488         /* check to see if parent event is still interested (in orig name).  */
2489         if(!foriq->dp) {
2490                 verbose(VERB_ALGO, "subq: parent not interested, was reset");
2491                 return; /* not interested anymore */
2492         }
2493         dpns = delegpt_find_ns(foriq->dp, qstate->qinfo.qname,
2494                         qstate->qinfo.qname_len);
2495         if(!dpns) {
2496                 /* If not interested, just stop processing this event */
2497                 verbose(VERB_ALGO, "subq: parent not interested anymore");
2498                 /* could be because parent was jostled out of the cache,
2499                    and a new identical query arrived, that does not want it*/
2500                 return;
2501         }
2502
2503         /* Tell the originating event that this target query has finished
2504          * (regardless if it succeeded or not). */
2505         foriq->num_target_queries--;
2506
2507         /* if iq->query_for_pside_glue then add the pside_glue (marked lame) */
2508         if(iq->pside_glue) {
2509                 /* if the pside_glue is NULL, then it could not be found,
2510                  * the done_pside is already set when created and a cache
2511                  * entry created in processFinished so nothing to do here */
2512                 log_rrset_key(VERB_ALGO, "add parentside glue to dp",
2513                         iq->pside_glue);
2514                 if(!delegpt_add_rrset(foriq->dp, forq->region,
2515                         iq->pside_glue, 1))
2516                         log_err("out of memory adding pside glue");
2517         }
2518
2519         /* This response is relevant to the current query, so we
2520          * add (attempt to add, anyway) this target(s) and reactivate
2521          * the original event.
2522          * NOTE: we could only look for the AnswerRRset if the
2523          * response type was ANSWER. */
2524         rrset = reply_find_answer_rrset(&iq->qchase, qstate->return_msg->rep);
2525         if(rrset) {
2526                 /* if CNAMEs have been followed - add new NS to delegpt. */
2527                 /* BTW. RFC 1918 says NS should not have got CNAMEs. Robust. */
2528                 if(!delegpt_find_ns(foriq->dp, rrset->rk.dname,
2529                         rrset->rk.dname_len)) {
2530                         /* if dpns->lame then set newcname ns lame too */
2531                         if(!delegpt_add_ns(foriq->dp, forq->region,
2532                                 rrset->rk.dname, dpns->lame))
2533                                 log_err("out of memory adding cnamed-ns");
2534                 }
2535                 /* if dpns->lame then set the address(es) lame too */
2536                 if(!delegpt_add_rrset(foriq->dp, forq->region, rrset,
2537                         dpns->lame))
2538                         log_err("out of memory adding targets");
2539                 verbose(VERB_ALGO, "added target response");
2540                 delegpt_log(VERB_ALGO, foriq->dp);
2541         } else {
2542                 verbose(VERB_ALGO, "iterator TargetResponse failed");
2543                 dpns->resolved = 1; /* fail the target */
2544         }
2545 }
2546
2547 /**
2548  * Process response for DS NS Find queries, that attempt to find the delegation
2549  * point where we ask the DS query from.
2550  *
2551  * @param qstate: query state.
2552  * @param id: module id.
2553  * @param forq: super query state.
2554  */
2555 static void
2556 processDSNSResponse(struct module_qstate* qstate, int id,
2557         struct module_qstate* forq)
2558 {
2559         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
2560
2561         /* if the finished (iq->response) query has no NS set: continue
2562          * up to look for the right dp; nothing to change, do DPNSstate */
2563         if(qstate->return_rcode != LDNS_RCODE_NOERROR)
2564                 return; /* seek further */
2565         /* find the NS RRset (without allowing CNAMEs) */
2566         if(!reply_find_rrset(qstate->return_msg->rep, qstate->qinfo.qname,
2567                 qstate->qinfo.qname_len, LDNS_RR_TYPE_NS,
2568                 qstate->qinfo.qclass)){
2569                 return; /* seek further */
2570         }
2571
2572         /* else, store as DP and continue at querytargets */
2573         foriq->state = QUERYTARGETS_STATE;
2574         foriq->dp = delegpt_from_message(qstate->return_msg, forq->region);
2575         if(!foriq->dp) {
2576                 log_err("out of memory in dsns dp alloc");
2577                 return; /* dp==NULL in QUERYTARGETS makes SERVFAIL */
2578         }
2579         /* success, go query the querytargets in the new dp (and go down) */
2580 }
2581
2582 /**
2583  * Process response for qclass=ANY queries for a particular class.
2584  * Append to result or error-exit.
2585  *
2586  * @param qstate: query state.
2587  * @param id: module id.
2588  * @param forq: super query state.
2589  */
2590 static void
2591 processClassResponse(struct module_qstate* qstate, int id,
2592         struct module_qstate* forq)
2593 {
2594         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
2595         struct dns_msg* from = qstate->return_msg;
2596         log_query_info(VERB_ALGO, "processClassResponse", &qstate->qinfo);
2597         log_query_info(VERB_ALGO, "processClassResponse super", &forq->qinfo);
2598         if(qstate->return_rcode != LDNS_RCODE_NOERROR) {
2599                 /* cause servfail for qclass ANY query */
2600                 foriq->response = NULL;
2601                 foriq->state = FINISHED_STATE;
2602                 return;
2603         }
2604         /* append result */
2605         if(!foriq->response) {
2606                 /* allocate the response: copy RCODE, sec_state */
2607                 foriq->response = dns_copy_msg(from, forq->region);
2608                 if(!foriq->response) {
2609                         log_err("malloc failed for qclass ANY response");
2610                         foriq->state = FINISHED_STATE;
2611                         return;
2612                 }
2613                 foriq->response->qinfo.qclass = forq->qinfo.qclass;
2614                 /* qclass ANY does not receive the AA flag on replies */
2615                 foriq->response->rep->authoritative = 0;
2616         } else {
2617                 struct dns_msg* to = foriq->response;
2618                 /* add _from_ this response _to_ existing collection */
2619                 /* if there are records, copy RCODE */
2620                 /* lower sec_state if this message is lower */
2621                 if(from->rep->rrset_count != 0) {
2622                         size_t n = from->rep->rrset_count+to->rep->rrset_count;
2623                         struct ub_packed_rrset_key** dest, **d;
2624                         /* copy appropriate rcode */
2625                         to->rep->flags = from->rep->flags;
2626                         /* copy rrsets */
2627                         if(from->rep->rrset_count > RR_COUNT_MAX ||
2628                                 to->rep->rrset_count > RR_COUNT_MAX) {
2629                                 log_err("malloc failed (too many rrsets) in collect ANY");
2630                                 foriq->state = FINISHED_STATE;
2631                                 return; /* integer overflow protection */
2632                         }
2633                         dest = regional_alloc(forq->region, sizeof(dest[0])*n);
2634                         if(!dest) {
2635                                 log_err("malloc failed in collect ANY");
2636                                 foriq->state = FINISHED_STATE;
2637                                 return;
2638                         }
2639                         d = dest;
2640                         /* copy AN */
2641                         memcpy(dest, to->rep->rrsets, to->rep->an_numrrsets
2642                                 * sizeof(dest[0]));
2643                         dest += to->rep->an_numrrsets;
2644                         memcpy(dest, from->rep->rrsets, from->rep->an_numrrsets
2645                                 * sizeof(dest[0]));
2646                         dest += from->rep->an_numrrsets;
2647                         /* copy NS */
2648                         memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets,
2649                                 to->rep->ns_numrrsets * sizeof(dest[0]));
2650                         dest += to->rep->ns_numrrsets;
2651                         memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets,
2652                                 from->rep->ns_numrrsets * sizeof(dest[0]));
2653                         dest += from->rep->ns_numrrsets;
2654                         /* copy AR */
2655                         memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets+
2656                                 to->rep->ns_numrrsets,
2657                                 to->rep->ar_numrrsets * sizeof(dest[0]));
2658                         dest += to->rep->ar_numrrsets;
2659                         memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets+
2660                                 from->rep->ns_numrrsets,
2661                                 from->rep->ar_numrrsets * sizeof(dest[0]));
2662                         /* update counts */
2663                         to->rep->rrsets = d;
2664                         to->rep->an_numrrsets += from->rep->an_numrrsets;
2665                         to->rep->ns_numrrsets += from->rep->ns_numrrsets;
2666                         to->rep->ar_numrrsets += from->rep->ar_numrrsets;
2667                         to->rep->rrset_count = n;
2668                 }
2669                 if(from->rep->security < to->rep->security) /* lowest sec */
2670                         to->rep->security = from->rep->security;
2671                 if(from->rep->qdcount != 0) /* insert qd if appropriate */
2672                         to->rep->qdcount = from->rep->qdcount;
2673                 if(from->rep->ttl < to->rep->ttl) /* use smallest TTL */
2674                         to->rep->ttl = from->rep->ttl;
2675                 if(from->rep->prefetch_ttl < to->rep->prefetch_ttl)
2676                         to->rep->prefetch_ttl = from->rep->prefetch_ttl;
2677         }
2678         /* are we done? */
2679         foriq->num_current_queries --;
2680         if(foriq->num_current_queries == 0)
2681                 foriq->state = FINISHED_STATE;
2682 }
2683
2684 /**
2685  * Collect class ANY responses and make them into one response.  This
2686  * state is started and it creates queries for all classes (that have
2687  * root hints).  The answers are then collected.
2688  *
2689  * @param qstate: query state.
2690  * @param id: module id.
2691  * @return true if the event needs more immediate processing, false if not.
2692  */
2693 static int
2694 processCollectClass(struct module_qstate* qstate, int id)
2695 {
2696         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
2697         struct module_qstate* subq;
2698         /* If qchase.qclass == 0 then send out queries for all classes.
2699          * Otherwise, do nothing (wait for all answers to arrive and the
2700          * processClassResponse to put them together, and that moves us
2701          * towards the Finished state when done. */
2702         if(iq->qchase.qclass == 0) {
2703                 uint16_t c = 0;
2704                 iq->qchase.qclass = LDNS_RR_CLASS_ANY;
2705                 while(iter_get_next_root(qstate->env->hints,
2706                         qstate->env->fwds, &c)) {
2707                         /* generate query for this class */
2708                         log_nametypeclass(VERB_ALGO, "spawn collect query",
2709                                 qstate->qinfo.qname, qstate->qinfo.qtype, c);
2710                         if(!generate_sub_request(qstate->qinfo.qname,
2711                                 qstate->qinfo.qname_len, qstate->qinfo.qtype,
2712                                 c, qstate, id, iq, INIT_REQUEST_STATE,
2713                                 FINISHED_STATE, &subq,
2714                                 (int)!(qstate->query_flags&BIT_CD))) {
2715                                 return error_response(qstate, id,
2716                                         LDNS_RCODE_SERVFAIL);
2717                         }
2718                         /* ignore subq, no special init required */
2719                         iq->num_current_queries ++;
2720                         if(c == 0xffff)
2721                                 break;
2722                         else c++;
2723                 }
2724                 /* if no roots are configured at all, return */
2725                 if(iq->num_current_queries == 0) {
2726                         verbose(VERB_ALGO, "No root hints or fwds, giving up "
2727                                 "on qclass ANY");
2728                         return error_response(qstate, id, LDNS_RCODE_REFUSED);
2729                 }
2730                 /* return false, wait for queries to return */
2731         }
2732         /* if woke up here because of an answer, wait for more answers */
2733         return 0;
2734 }
2735
2736 /**
2737  * This handles the final state for first-tier responses (i.e., responses to
2738  * externally generated queries).
2739  *
2740  * @param qstate: query state.
2741  * @param iq: iterator query state.
2742  * @param id: module id.
2743  * @return true if the event needs more processing, false if not. Since this
2744  *         is the final state for an event, it always returns false.
2745  */
2746 static int
2747 processFinished(struct module_qstate* qstate, struct iter_qstate* iq,
2748         int id)
2749 {
2750         log_query_info(VERB_QUERY, "finishing processing for",
2751                 &qstate->qinfo);
2752
2753         /* store negative cache element for parent side glue. */
2754         if(iq->query_for_pside_glue && !iq->pside_glue)
2755                 iter_store_parentside_neg(qstate->env, &qstate->qinfo,
2756                         iq->deleg_msg?iq->deleg_msg->rep:
2757                         (iq->response?iq->response->rep:NULL));
2758         if(!iq->response) {
2759                 verbose(VERB_ALGO, "No response is set, servfail");
2760                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2761         }
2762
2763         /* Make sure that the RA flag is set (since the presence of
2764          * this module means that recursion is available) */
2765         iq->response->rep->flags |= BIT_RA;
2766
2767         /* Clear the AA flag */
2768         /* FIXME: does this action go here or in some other module? */
2769         iq->response->rep->flags &= ~BIT_AA;
2770
2771         /* make sure QR flag is on */
2772         iq->response->rep->flags |= BIT_QR;
2773
2774         /* we have finished processing this query */
2775         qstate->ext_state[id] = module_finished;
2776
2777         /* TODO:  we are using a private TTL, trim the response. */
2778         /* if (mPrivateTTL > 0){IterUtils.setPrivateTTL(resp, mPrivateTTL); } */
2779
2780         /* prepend any items we have accumulated */
2781         if(iq->an_prepend_list || iq->ns_prepend_list) {
2782                 if(!iter_prepend(iq, iq->response, qstate->region)) {
2783                         log_err("prepend rrsets: out of memory");
2784                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2785                 }
2786                 /* reset the query name back */
2787                 iq->response->qinfo = qstate->qinfo;
2788                 /* the security state depends on the combination */
2789                 iq->response->rep->security = sec_status_unchecked;
2790                 /* store message with the finished prepended items,
2791                  * but only if we did recursion. The nonrecursion referral
2792                  * from cache does not need to be stored in the msg cache. */
2793                 if(qstate->query_flags&BIT_RD) {
2794                         iter_dns_store(qstate->env, &qstate->qinfo,
2795                                 iq->response->rep, 0, qstate->prefetch_leeway,
2796                                 iq->dp&&iq->dp->has_parent_side_NS,
2797                                 qstate->region, qstate->query_flags);
2798                 }
2799         }
2800         qstate->return_rcode = LDNS_RCODE_NOERROR;
2801         qstate->return_msg = iq->response;
2802         return 0;
2803 }
2804
2805 /*
2806  * Return priming query results to interestes super querystates.
2807  *
2808  * Sets the delegation point and delegation message (not nonRD queries).
2809  * This is a callback from walk_supers.
2810  *
2811  * @param qstate: query state that finished.
2812  * @param id: module id.
2813  * @param super: the qstate to inform.
2814  */
2815 void
2816 iter_inform_super(struct module_qstate* qstate, int id,
2817         struct module_qstate* super)
2818 {
2819         if(!qstate->is_priming && super->qinfo.qclass == LDNS_RR_CLASS_ANY)
2820                 processClassResponse(qstate, id, super);
2821         else if(super->qinfo.qtype == LDNS_RR_TYPE_DS && ((struct iter_qstate*)
2822                 super->minfo[id])->state == DSNS_FIND_STATE)
2823                 processDSNSResponse(qstate, id, super);
2824         else if(qstate->return_rcode != LDNS_RCODE_NOERROR)
2825                 error_supers(qstate, id, super);
2826         else if(qstate->is_priming)
2827                 prime_supers(qstate, id, super);
2828         else    processTargetResponse(qstate, id, super);
2829 }
2830
2831 /**
2832  * Handle iterator state.
2833  * Handle events. This is the real processing loop for events, responsible
2834  * for moving events through the various states. If a processing method
2835  * returns true, then it will be advanced to the next state. If false, then
2836  * processing will stop.
2837  *
2838  * @param qstate: query state.
2839  * @param ie: iterator shared global environment.
2840  * @param iq: iterator query state.
2841  * @param id: module id.
2842  */
2843 static void
2844 iter_handle(struct module_qstate* qstate, struct iter_qstate* iq,
2845         struct iter_env* ie, int id)
2846 {
2847         int cont = 1;
2848         while(cont) {
2849                 verbose(VERB_ALGO, "iter_handle processing q with state %s",
2850                         iter_state_to_string(iq->state));
2851                 switch(iq->state) {
2852                         case INIT_REQUEST_STATE:
2853                                 cont = processInitRequest(qstate, iq, ie, id);
2854                                 break;
2855                         case INIT_REQUEST_2_STATE:
2856                                 cont = processInitRequest2(qstate, iq, id);
2857                                 break;
2858                         case INIT_REQUEST_3_STATE:
2859                                 cont = processInitRequest3(qstate, iq, id);
2860                                 break;
2861                         case QUERYTARGETS_STATE:
2862                                 cont = processQueryTargets(qstate, iq, ie, id);
2863                                 break;
2864                         case QUERY_RESP_STATE:
2865                                 cont = processQueryResponse(qstate, iq, id);
2866                                 break;
2867                         case PRIME_RESP_STATE:
2868                                 cont = processPrimeResponse(qstate, id);
2869                                 break;
2870                         case COLLECT_CLASS_STATE:
2871                                 cont = processCollectClass(qstate, id);
2872                                 break;
2873                         case DSNS_FIND_STATE:
2874                                 cont = processDSNSFind(qstate, iq, id);
2875                                 break;
2876                         case FINISHED_STATE:
2877                                 cont = processFinished(qstate, iq, id);
2878                                 break;
2879                         default:
2880                                 log_warn("iterator: invalid state: %d",
2881                                         iq->state);
2882                                 cont = 0;
2883                                 break;
2884                 }
2885         }
2886 }
2887
2888 /**
2889  * This is the primary entry point for processing request events. Note that
2890  * this method should only be used by external modules.
2891  * @param qstate: query state.
2892  * @param ie: iterator shared global environment.
2893  * @param iq: iterator query state.
2894  * @param id: module id.
2895  */
2896 static void
2897 process_request(struct module_qstate* qstate, struct iter_qstate* iq,
2898         struct iter_env* ie, int id)
2899 {
2900         /* external requests start in the INIT state, and finish using the
2901          * FINISHED state. */
2902         iq->state = INIT_REQUEST_STATE;
2903         iq->final_state = FINISHED_STATE;
2904         verbose(VERB_ALGO, "process_request: new external request event");
2905         iter_handle(qstate, iq, ie, id);
2906 }
2907
2908 /** process authoritative server reply */
2909 static void
2910 process_response(struct module_qstate* qstate, struct iter_qstate* iq,
2911         struct iter_env* ie, int id, struct outbound_entry* outbound,
2912         enum module_ev event)
2913 {
2914         struct msg_parse* prs;
2915         struct edns_data edns;
2916         sldns_buffer* pkt;
2917
2918         verbose(VERB_ALGO, "process_response: new external response event");
2919         iq->response = NULL;
2920         iq->state = QUERY_RESP_STATE;
2921         if(event == module_event_noreply || event == module_event_error) {
2922                 if(event == module_event_noreply && iq->sent_count >= 3 &&
2923                         qstate->env->cfg->use_caps_bits_for_id &&
2924                         !iq->caps_fallback) {
2925                         /* start fallback */
2926                         iq->caps_fallback = 1;
2927                         iq->caps_server = 0;
2928                         iq->caps_reply = NULL;
2929                         iq->caps_response = NULL;
2930                         iq->state = QUERYTARGETS_STATE;
2931                         iq->num_current_queries--;
2932                         /* need fresh attempts for the 0x20 fallback, if
2933                          * that was the cause for the failure */
2934                         iter_dec_attempts(iq->dp, 3);
2935                         verbose(VERB_DETAIL, "Capsforid: timeouts, starting fallback");
2936                         goto handle_it;
2937                 }
2938                 goto handle_it;
2939         }
2940         if( (event != module_event_reply && event != module_event_capsfail)
2941                 || !qstate->reply) {
2942                 log_err("Bad event combined with response");
2943                 outbound_list_remove(&iq->outlist, outbound);
2944                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2945                 return;
2946         }
2947
2948         /* parse message */
2949         prs = (struct msg_parse*)regional_alloc(qstate->env->scratch,
2950                 sizeof(struct msg_parse));
2951         if(!prs) {
2952                 log_err("out of memory on incoming message");
2953                 /* like packet got dropped */
2954                 goto handle_it;
2955         }
2956         memset(prs, 0, sizeof(*prs));
2957         memset(&edns, 0, sizeof(edns));
2958         pkt = qstate->reply->c->buffer;
2959         sldns_buffer_set_position(pkt, 0);
2960         if(parse_packet(pkt, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) {
2961                 verbose(VERB_ALGO, "parse error on reply packet");
2962                 goto handle_it;
2963         }
2964         /* edns is not examined, but removed from message to help cache */
2965         if(parse_extract_edns(prs, &edns) != LDNS_RCODE_NOERROR)
2966                 goto handle_it;
2967         /* remove CD-bit, we asked for in case we handle validation ourself */
2968         prs->flags &= ~BIT_CD;
2969
2970         /* normalize and sanitize: easy to delete items from linked lists */
2971         if(!scrub_message(pkt, prs, &iq->qchase, iq->dp->name,
2972                 qstate->env->scratch, qstate->env, ie)) {
2973                 /* if 0x20 enabled, start fallback, but we have no message */
2974                 if(event == module_event_capsfail && !iq->caps_fallback) {
2975                         iq->caps_fallback = 1;
2976                         iq->caps_server = 0;
2977                         iq->caps_reply = NULL;
2978                         iq->caps_response = NULL;
2979                         iq->state = QUERYTARGETS_STATE;
2980                         iq->num_current_queries--;
2981                         verbose(VERB_DETAIL, "Capsforid: scrub failed, starting fallback with no response");
2982                 }
2983                 goto handle_it;
2984         }
2985
2986         /* allocate response dns_msg in region */
2987         iq->response = dns_alloc_msg(pkt, prs, qstate->region);
2988         if(!iq->response)
2989                 goto handle_it;
2990         log_query_info(VERB_DETAIL, "response for", &qstate->qinfo);
2991         log_name_addr(VERB_DETAIL, "reply from", iq->dp->name,
2992                 &qstate->reply->addr, qstate->reply->addrlen);
2993         if(verbosity >= VERB_ALGO)
2994                 log_dns_msg("incoming scrubbed packet:", &iq->response->qinfo,
2995                         iq->response->rep);
2996
2997         if(event == module_event_capsfail || iq->caps_fallback) {
2998                 /* for fallback we care about main answer, not additionals */
2999                 /* removing that makes comparison more likely to succeed */
3000                 caps_strip_reply(iq->response->rep);
3001                 if(!iq->caps_fallback) {
3002                         /* start fallback */
3003                         iq->caps_fallback = 1;
3004                         iq->caps_server = 0;
3005                         iq->caps_reply = iq->response->rep;
3006                         iq->caps_response = iq->response;
3007                         iq->state = QUERYTARGETS_STATE;
3008                         iq->num_current_queries--;
3009                         verbose(VERB_DETAIL, "Capsforid: starting fallback");
3010                         goto handle_it;
3011                 } else {
3012                         /* check if reply is the same, otherwise, fail */
3013                         if(!iq->caps_reply) {
3014                                 iq->caps_reply = iq->response->rep;
3015                                 iq->caps_response = iq->response;
3016                                 iq->caps_server = -1; /*become zero at ++,
3017                                 so that we start the full set of trials */
3018                         } else if(caps_failed_rcode(iq->caps_reply) &&
3019                                 !caps_failed_rcode(iq->response->rep)) {
3020                                 /* prefer to upgrade to non-SERVFAIL */
3021                                 iq->caps_reply = iq->response->rep;
3022                                 iq->caps_response = iq->response;
3023                         } else if(!caps_failed_rcode(iq->caps_reply) &&
3024                                 caps_failed_rcode(iq->response->rep)) {
3025                                 /* if we have non-SERVFAIL as answer then
3026                                  * we can ignore SERVFAILs for the equality
3027                                  * comparison */
3028                                 /* no instructions here, skip other else */
3029                         } else if(caps_failed_rcode(iq->caps_reply) &&
3030                                 caps_failed_rcode(iq->response->rep)) {
3031                                 /* failure is same as other failure in fallbk*/
3032                                 /* no instructions here, skip other else */
3033                         } else if(!reply_equal(iq->response->rep, iq->caps_reply,
3034                                 qstate->env->scratch)) {
3035                                 verbose(VERB_DETAIL, "Capsforid fallback: "
3036                                         "getting different replies, failed");
3037                                 outbound_list_remove(&iq->outlist, outbound);
3038                                 (void)error_response(qstate, id,
3039                                         LDNS_RCODE_SERVFAIL);
3040                                 return;
3041                         }
3042                         /* continue the fallback procedure at next server */
3043                         iq->caps_server++;
3044                         iq->state = QUERYTARGETS_STATE;
3045                         iq->num_current_queries--;
3046                         verbose(VERB_DETAIL, "Capsforid: reply is equal. "
3047                                 "go to next fallback");
3048                         goto handle_it;
3049                 }
3050         }
3051         iq->caps_fallback = 0; /* if we were in fallback, 0x20 is OK now */
3052
3053 handle_it:
3054         outbound_list_remove(&iq->outlist, outbound);
3055         iter_handle(qstate, iq, ie, id);
3056 }
3057
3058 void
3059 iter_operate(struct module_qstate* qstate, enum module_ev event, int id,
3060         struct outbound_entry* outbound)
3061 {
3062         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
3063         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3064         verbose(VERB_QUERY, "iterator[module %d] operate: extstate:%s event:%s",
3065                 id, strextstate(qstate->ext_state[id]), strmodulevent(event));
3066         if(iq) log_query_info(VERB_QUERY, "iterator operate: query",
3067                 &qstate->qinfo);
3068         if(iq && qstate->qinfo.qname != iq->qchase.qname)
3069                 log_query_info(VERB_QUERY, "iterator operate: chased to",
3070                         &iq->qchase);
3071
3072         /* perform iterator state machine */
3073         if((event == module_event_new || event == module_event_pass) &&
3074                 iq == NULL) {
3075                 if(!iter_new(qstate, id)) {
3076                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3077                         return;
3078                 }
3079                 iq = (struct iter_qstate*)qstate->minfo[id];
3080                 process_request(qstate, iq, ie, id);
3081                 return;
3082         }
3083         if(iq && event == module_event_pass) {
3084                 iter_handle(qstate, iq, ie, id);
3085                 return;
3086         }
3087         if(iq && outbound) {
3088                 process_response(qstate, iq, ie, id, outbound, event);
3089                 return;
3090         }
3091         if(event == module_event_error) {
3092                 verbose(VERB_ALGO, "got called with event error, giving up");
3093                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3094                 return;
3095         }
3096
3097         log_err("bad event for iterator");
3098         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3099 }
3100
3101 void
3102 iter_clear(struct module_qstate* qstate, int id)
3103 {
3104         struct iter_qstate* iq;
3105         if(!qstate)
3106                 return;
3107         iq = (struct iter_qstate*)qstate->minfo[id];
3108         if(iq) {
3109                 outbound_list_clear(&iq->outlist);
3110                 if(iq->target_count && --iq->target_count[0] == 0)
3111                         free(iq->target_count);
3112                 iq->num_current_queries = 0;
3113         }
3114         qstate->minfo[id] = NULL;
3115 }
3116
3117 size_t
3118 iter_get_mem(struct module_env* env, int id)
3119 {
3120         struct iter_env* ie = (struct iter_env*)env->modinfo[id];
3121         if(!ie)
3122                 return 0;
3123         return sizeof(*ie) + sizeof(int)*((size_t)ie->max_dependency_depth+1)
3124                 + donotq_get_mem(ie->donotq) + priv_get_mem(ie->priv);
3125 }
3126
3127 /**
3128  * The iterator function block
3129  */
3130 static struct module_func_block iter_block = {
3131         "iterator",
3132         &iter_init, &iter_deinit, &iter_operate, &iter_inform_super,
3133         &iter_clear, &iter_get_mem
3134 };
3135
3136 struct module_func_block*
3137 iter_get_funcblock(void)
3138 {
3139         return &iter_block;
3140 }
3141
3142 const char*
3143 iter_state_to_string(enum iter_state state)
3144 {
3145         switch (state)
3146         {
3147         case INIT_REQUEST_STATE :
3148                 return "INIT REQUEST STATE";
3149         case INIT_REQUEST_2_STATE :
3150                 return "INIT REQUEST STATE (stage 2)";
3151         case INIT_REQUEST_3_STATE:
3152                 return "INIT REQUEST STATE (stage 3)";
3153         case QUERYTARGETS_STATE :
3154                 return "QUERY TARGETS STATE";
3155         case PRIME_RESP_STATE :
3156                 return "PRIME RESPONSE STATE";
3157         case COLLECT_CLASS_STATE :
3158                 return "COLLECT CLASS STATE";
3159         case DSNS_FIND_STATE :
3160                 return "DSNS FIND STATE";
3161         case QUERY_RESP_STATE :
3162                 return "QUERY RESPONSE STATE";
3163         case FINISHED_STATE :
3164                 return "FINISHED RESPONSE STATE";
3165         default :
3166                 return "UNKNOWN ITER STATE";
3167         }
3168 }
3169
3170 int
3171 iter_state_is_responsestate(enum iter_state s)
3172 {
3173         switch(s) {
3174                 case INIT_REQUEST_STATE :
3175                 case INIT_REQUEST_2_STATE :
3176                 case INIT_REQUEST_3_STATE :
3177                 case QUERYTARGETS_STATE :
3178                 case COLLECT_CLASS_STATE :
3179                         return 0;
3180                 default:
3181                         break;
3182         }
3183         return 1;
3184 }