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 recursive 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 "services/authzone.h"
  57 #include "util/module.h"
  58 #include "util/netevent.h"
  59 #include "util/net_help.h"
  60 #include "util/regional.h"
  61 #include "util/data/dname.h"
  62 #include "util/data/msgencode.h"
  63 #include "util/fptr_wlist.h"
  64 #include "util/config_file.h"
  65 #include "util/random.h"
  66 #include "sldns/rrdef.h"
  67 #include "sldns/wire2str.h"
  68 #include "sldns/str2wire.h"
  69 #include "sldns/parseutil.h"
  70 #include "sldns/sbuffer.h"
  71
  72 /* in msec */
  73 int UNKNOWN_SERVER_NICENESS = 376;
  74
  75 static void target_count_increase_nx(struct iter_qstate* iq, int num);
  76
  77 int
  78 iter_init(struct module_env* env, int id)
  79 {
  80         struct iter_env* iter_env = (struct iter_env*)calloc(1,
  81                 sizeof(struct iter_env));
  82         if(!iter_env) {
  83                 log_err("malloc failure");
  84                 return 0;
  85         }
  86         env->modinfo[id] = (void*)iter_env;
  87
  88         lock_basic_init(&iter_env->queries_ratelimit_lock);
  89         lock_protect(&iter_env->queries_ratelimit_lock,
  90                         &iter_env->num_queries_ratelimited,
  91                 sizeof(iter_env->num_queries_ratelimited));
  92
  93         if(!iter_apply_cfg(iter_env, env->cfg)) {
  94                 log_err("iterator: could not apply configuration settings.");
  95                 return 0;
  96         }
  97
  98         return 1;
  99 }
 100
 101 /** delete caps_whitelist element */
 102 static void
 103 caps_free(struct rbnode_type* n, void* ATTR_UNUSED(d))
 104 {
 105         if(n) {
 106                 free(((struct name_tree_node*)n)->name);
 107                 free(n);
 108         }
 109 }
 110
 111 void
 112 iter_deinit(struct module_env* env, int id)
 113 {
 114         struct iter_env* iter_env;
 115         if(!env || !env->modinfo[id])
 116                 return;
 117         iter_env = (struct iter_env*)env->modinfo[id];
 118         lock_basic_destroy(&iter_env->queries_ratelimit_lock);
 119         free(iter_env->target_fetch_policy);
 120         priv_delete(iter_env->priv);
 121         donotq_delete(iter_env->donotq);
 122         if(iter_env->caps_white) {
 123                 traverse_postorder(iter_env->caps_white, caps_free, NULL);
 124                 free(iter_env->caps_white);
 125         }
 126         free(iter_env);
 127         env->modinfo[id] = NULL;
 128 }
 129
 130 /** new query for iterator */
 131 static int
 132 iter_new(struct module_qstate* qstate, int id)
 133 {
 134         struct iter_qstate* iq = (struct iter_qstate*)regional_alloc(
 135                 qstate->region, sizeof(struct iter_qstate));
 136         qstate->minfo[id] = iq;
 137         if(!iq)
 138                 return 0;
 139         memset(iq, 0, sizeof(*iq));
 140         iq->state = INIT_REQUEST_STATE;
 141         iq->final_state = FINISHED_STATE;
 142         iq->an_prepend_list = NULL;
 143         iq->an_prepend_last = NULL;
 144         iq->ns_prepend_list = NULL;
 145         iq->ns_prepend_last = NULL;
 146         iq->dp = NULL;
 147         iq->depth = 0;
 148         iq->num_target_queries = 0;
 149         iq->num_current_queries = 0;
 150         iq->query_restart_count = 0;
 151         iq->referral_count = 0;
 152         iq->sent_count = 0;
 153         iq->ratelimit_ok = 0;
 154         iq->target_count = NULL;
 155         iq->dp_target_count = 0;
 156         iq->wait_priming_stub = 0;
 157         iq->refetch_glue = 0;
 158         iq->dnssec_expected = 0;
 159         iq->dnssec_lame_query = 0;
 160         iq->chase_flags = qstate->query_flags;
 161         /* Start with the (current) qname. */
 162         iq->qchase = qstate->qinfo;
 163         outbound_list_init(&iq->outlist);
 164         iq->minimise_count = 0;
 165         iq->minimise_timeout_count = 0;
 166         if (qstate->env->cfg->qname_minimisation)
 167                 iq->minimisation_state = INIT_MINIMISE_STATE;
 168         else
 169                 iq->minimisation_state = DONOT_MINIMISE_STATE;
 170
 171         memset(&iq->qinfo_out, 0, sizeof(struct query_info));
 172         return 1;
 173 }
 174
 175 /**
 176  * Transition to the next state. This can be used to advance a currently
 177  * processing event. It cannot be used to reactivate a forEvent.
 178  *
 179  * @param iq: iterator query state
 180  * @param nextstate The state to transition to.
 181  * @return true. This is so this can be called as the return value for the
 182  *         actual process*State() methods. (Transitioning to the next state
 183  *         implies further processing).
 184  */
 185 static int
 186 next_state(struct iter_qstate* iq, enum iter_state nextstate)
 187 {
 188         /* If transitioning to a "response" state, make sure that there is a
 189          * response */
 190         if(iter_state_is_responsestate(nextstate)) {
 191                 if(iq->response == NULL) {
 192                         log_err("transitioning to response state sans "
 193                                 "response.");
 194                 }
 195         }
 196         iq->state = nextstate;
 197         return 1;
 198 }
 199
 200 /**
 201  * Transition an event to its final state. Final states always either return
 202  * a result up the module chain, or reactivate a dependent event. Which
 203  * final state to transition to is set in the module state for the event when
 204  * it was created, and depends on the original purpose of the event.
 205  *
 206  * The response is stored in the qstate->buf buffer.
 207  *
 208  * @param iq: iterator query state
 209  * @return false. This is so this method can be used as the return value for
 210  *         the processState methods. (Transitioning to the final state
 211  */
 212 static int
 213 final_state(struct iter_qstate* iq)
 214 {
 215         return next_state(iq, iq->final_state);
 216 }
 217
 218 /**
 219  * Callback routine to handle errors in parent query states
 220  * @param qstate: query state that failed.
 221  * @param id: module id.
 222  * @param super: super state.
 223  */
 224 static void
 225 error_supers(struct module_qstate* qstate, int id, struct module_qstate* super)
 226 {
 227         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
 228         struct iter_qstate* super_iq = (struct iter_qstate*)super->minfo[id];
 229
 230         if(qstate->qinfo.qtype == LDNS_RR_TYPE_A ||
 231                 qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA) {
 232                 /* mark address as failed. */
 233                 struct delegpt_ns* dpns = NULL;
 234                 super_iq->num_target_queries--;
 235                 if(super_iq->dp)
 236                         dpns = delegpt_find_ns(super_iq->dp,
 237                                 qstate->qinfo.qname, qstate->qinfo.qname_len);
 238                 if(!dpns) {
 239                         /* not interested */
 240                         /* this can happen, for eg. qname minimisation asked
 241                          * for an NXDOMAIN to be validated, and used qtype
 242                          * A for that, and the error of that, the name, is
 243                          * not listed in super_iq->dp */
 244                         verbose(VERB_ALGO, "subq error, but not interested");
 245                         log_query_info(VERB_ALGO, "superq", &super->qinfo);
 246                         return;
 247                 } else {
 248                         /* see if the failure did get (parent-lame) info */
 249                         if(!cache_fill_missing(super->env, super_iq->qchase.qclass,
 250                                 super->region, super_iq->dp))
 251                                 log_err("out of memory adding missing");
 252                 }
 253                 delegpt_mark_neg(dpns, qstate->qinfo.qtype);
 254                 dpns->resolved = 1; /* mark as failed */
 255                 if((dpns->got4 == 2 || !ie->supports_ipv4) &&
 256                         (dpns->got6 == 2 || !ie->supports_ipv6))
 257                         target_count_increase_nx(super_iq, 1);
 258         }
 259         if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS) {
 260                 /* prime failed to get delegation */
 261                 super_iq->dp = NULL;
 262         }
 263         /* evaluate targets again */
 264         super_iq->state = QUERYTARGETS_STATE;
 265         /* super becomes runnable, and will process this change */
 266 }
 267
 268 /**
 269  * Return an error to the client
 270  * @param qstate: our query state
 271  * @param id: module id
 272  * @param rcode: error code (DNS errcode).
 273  * @return: 0 for use by caller, to make notation easy, like:
 274  *      return error_response(..).
 275  */
 276 static int
 277 error_response(struct module_qstate* qstate, int id, int rcode)
 278 {
 279         verbose(VERB_QUERY, "return error response %s",
 280                 sldns_lookup_by_id(sldns_rcodes, rcode)?
 281                 sldns_lookup_by_id(sldns_rcodes, rcode)->name:"??");
 282         qstate->return_rcode = rcode;
 283         qstate->return_msg = NULL;
 284         qstate->ext_state[id] = module_finished;
 285         return 0;
 286 }
 287
 288 /**
 289  * Return an error to the client and cache the error code in the
 290  * message cache (so per qname, qtype, qclass).
 291  * @param qstate: our query state
 292  * @param id: module id
 293  * @param rcode: error code (DNS errcode).
 294  * @return: 0 for use by caller, to make notation easy, like:
 295  *      return error_response(..).
 296  */
 297 static int
 298 error_response_cache(struct module_qstate* qstate, int id, int rcode)
 299 {
 300         if(!qstate->no_cache_store) {
 301                 /* store in cache */
 302                 struct reply_info err;
 303                 if(qstate->prefetch_leeway > NORR_TTL) {
 304                         verbose(VERB_ALGO, "error response for prefetch in cache");
 305                         /* attempt to adjust the cache entry prefetch */
 306                         if(dns_cache_prefetch_adjust(qstate->env, &qstate->qinfo,
 307                                 NORR_TTL, qstate->query_flags))
 308                                 return error_response(qstate, id, rcode);
 309                         /* if that fails (not in cache), fall through to store err */
 310                 }
 311                 if(qstate->env->cfg->serve_expired) {
 312                         /* if serving expired contents, and such content is
 313                          * already available, don't overwrite this servfail */
 314                         struct msgreply_entry* msg;
 315                         if((msg=msg_cache_lookup(qstate->env,
 316                                 qstate->qinfo.qname, qstate->qinfo.qname_len,
 317                                 qstate->qinfo.qtype, qstate->qinfo.qclass,
 318                                 qstate->query_flags, 0,
 319                                 qstate->env->cfg->serve_expired_ttl_reset))
 320                                 != NULL) {
 321                                 if(qstate->env->cfg->serve_expired_ttl_reset) {
 322                                         struct reply_info* rep =
 323                                                 (struct reply_info*)msg->entry.data;
 324                                         if(rep && *qstate->env->now +
 325                                                 qstate->env->cfg->serve_expired_ttl  >
 326                                                 rep->serve_expired_ttl) {
 327                                                 rep->serve_expired_ttl =
 328                                                         *qstate->env->now +
 329                                                         qstate->env->cfg->serve_expired_ttl;
 330                                         }
 331                                 }
 332                                 lock_rw_unlock(&msg->entry.lock);
 333                                 return error_response(qstate, id, rcode);
 334                         }
 335                         /* serving expired contents, but nothing is cached
 336                          * at all, so the servfail cache entry is useful
 337                          * (stops waste of time on this servfail NORR_TTL) */
 338                 } else {
 339                         /* don't overwrite existing (non-expired) data in
 340                          * cache with a servfail */
 341                         struct msgreply_entry* msg;
 342                         if((msg=msg_cache_lookup(qstate->env,
 343                                 qstate->qinfo.qname, qstate->qinfo.qname_len,
 344                                 qstate->qinfo.qtype, qstate->qinfo.qclass,
 345                                 qstate->query_flags, *qstate->env->now, 0))
 346                                 != NULL) {
 347                                 struct reply_info* rep = (struct reply_info*)
 348                                         msg->entry.data;
 349                                 if(FLAGS_GET_RCODE(rep->flags) ==
 350                                         LDNS_RCODE_NOERROR ||
 351                                         FLAGS_GET_RCODE(rep->flags) ==
 352                                         LDNS_RCODE_NXDOMAIN) {
 353                                         /* we have a good entry,
 354                                          * don't overwrite */
 355                                         lock_rw_unlock(&msg->entry.lock);
 356                                         return error_response(qstate, id, rcode);
 357                                 }
 358                                 lock_rw_unlock(&msg->entry.lock);
 359                         }
 360
 361                 }
 362                 memset(&err, 0, sizeof(err));
 363                 err.flags = (uint16_t)(BIT_QR | BIT_RA);
 364                 FLAGS_SET_RCODE(err.flags, rcode);
 365                 err.qdcount = 1;
 366                 err.ttl = NORR_TTL;
 367                 err.prefetch_ttl = PREFETCH_TTL_CALC(err.ttl);
 368                 err.serve_expired_ttl = NORR_TTL;
 369                 /* do not waste time trying to validate this servfail */
 370                 err.security = sec_status_indeterminate;
 371                 verbose(VERB_ALGO, "store error response in message cache");
 372                 iter_dns_store(qstate->env, &qstate->qinfo, &err, 0, 0, 0, NULL,
 373                         qstate->query_flags);
 374         }
 375         return error_response(qstate, id, rcode);
 376 }
 377
 378 /** check if prepend item is duplicate item */
 379 static int
 380 prepend_is_duplicate(struct ub_packed_rrset_key** sets, size_t to,
 381         struct ub_packed_rrset_key* dup)
 382 {
 383         size_t i;
 384         for(i=0; i<to; i++) {
 385                 if(sets[i]->rk.type == dup->rk.type &&
 386                         sets[i]->rk.rrset_class == dup->rk.rrset_class &&
 387                         sets[i]->rk.dname_len == dup->rk.dname_len &&
 388                         query_dname_compare(sets[i]->rk.dname, dup->rk.dname)
 389                         == 0)
 390                         return 1;
 391         }
 392         return 0;
 393 }
 394
 395 /** prepend the prepend list in the answer and authority section of dns_msg */
 396 static int
 397 iter_prepend(struct iter_qstate* iq, struct dns_msg* msg,
 398         struct regional* region)
 399 {
 400         struct iter_prep_list* p;
 401         struct ub_packed_rrset_key** sets;
 402         size_t num_an = 0, num_ns = 0;;
 403         for(p = iq->an_prepend_list; p; p = p->next)
 404                 num_an++;
 405         for(p = iq->ns_prepend_list; p; p = p->next)
 406                 num_ns++;
 407         if(num_an + num_ns == 0)
 408                 return 1;
 409         verbose(VERB_ALGO, "prepending %d rrsets", (int)num_an + (int)num_ns);
 410         if(num_an > RR_COUNT_MAX || num_ns > RR_COUNT_MAX ||
 411                 msg->rep->rrset_count > RR_COUNT_MAX) return 0; /* overflow */
 412         sets = regional_alloc(region, (num_an+num_ns+msg->rep->rrset_count) *
 413                 sizeof(struct ub_packed_rrset_key*));
 414         if(!sets)
 415                 return 0;
 416         /* ANSWER section */
 417         num_an = 0;
 418         for(p = iq->an_prepend_list; p; p = p->next) {
 419                 sets[num_an++] = p->rrset;
 420                 if(ub_packed_rrset_ttl(p->rrset) < msg->rep->ttl)
 421                         msg->rep->ttl = ub_packed_rrset_ttl(p->rrset);
 422         }
 423         memcpy(sets+num_an, msg->rep->rrsets, msg->rep->an_numrrsets *
 424                 sizeof(struct ub_packed_rrset_key*));
 425         /* AUTH section */
 426         num_ns = 0;
 427         for(p = iq->ns_prepend_list; p; p = p->next) {
 428                 if(prepend_is_duplicate(sets+msg->rep->an_numrrsets+num_an,
 429                         num_ns, p->rrset) || prepend_is_duplicate(
 430                         msg->rep->rrsets+msg->rep->an_numrrsets,
 431                         msg->rep->ns_numrrsets, p->rrset))
 432                         continue;
 433                 sets[msg->rep->an_numrrsets + num_an + num_ns++] = p->rrset;
 434                 if(ub_packed_rrset_ttl(p->rrset) < msg->rep->ttl)
 435                         msg->rep->ttl = ub_packed_rrset_ttl(p->rrset);
 436         }
 437         memcpy(sets + num_an + msg->rep->an_numrrsets + num_ns,
 438                 msg->rep->rrsets + msg->rep->an_numrrsets,
 439                 (msg->rep->ns_numrrsets + msg->rep->ar_numrrsets) *
 440                 sizeof(struct ub_packed_rrset_key*));
 441
 442         /* NXDOMAIN rcode can stay if we prepended DNAME/CNAMEs, because
 443          * this is what recursors should give. */
 444         msg->rep->rrset_count += num_an + num_ns;
 445         msg->rep->an_numrrsets += num_an;
 446         msg->rep->ns_numrrsets += num_ns;
 447         msg->rep->rrsets = sets;
 448         return 1;
 449 }
 450
 451 /**
 452  * Find rrset in ANSWER prepend list.
 453  * to avoid duplicate DNAMEs when a DNAME is traversed twice.
 454  * @param iq: iterator query state.
 455  * @param rrset: rrset to add.
 456  * @return false if not found
 457  */
 458 static int
 459 iter_find_rrset_in_prepend_answer(struct iter_qstate* iq,
 460         struct ub_packed_rrset_key* rrset)
 461 {
 462         struct iter_prep_list* p = iq->an_prepend_list;
 463         while(p) {
 464                 if(ub_rrset_compare(p->rrset, rrset) == 0 &&
 465                         rrsetdata_equal((struct packed_rrset_data*)p->rrset
 466                         ->entry.data, (struct packed_rrset_data*)rrset
 467                         ->entry.data))
 468                         return 1;
 469                 p = p->next;
 470         }
 471         return 0;
 472 }
 473
 474 /**
 475  * Add rrset to ANSWER prepend list
 476  * @param qstate: query state.
 477  * @param iq: iterator query state.
 478  * @param rrset: rrset to add.
 479  * @return false on failure (malloc).
 480  */
 481 static int
 482 iter_add_prepend_answer(struct module_qstate* qstate, struct iter_qstate* iq,
 483         struct ub_packed_rrset_key* rrset)
 484 {
 485         struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc(
 486                 qstate->region, sizeof(struct iter_prep_list));
 487         if(!p)
 488                 return 0;
 489         p->rrset = rrset;
 490         p->next = NULL;
 491         /* add at end */
 492         if(iq->an_prepend_last)
 493                 iq->an_prepend_last->next = p;
 494         else    iq->an_prepend_list = p;
 495         iq->an_prepend_last = p;
 496         return 1;
 497 }
 498
 499 /**
 500  * Add rrset to AUTHORITY prepend list
 501  * @param qstate: query state.
 502  * @param iq: iterator query state.
 503  * @param rrset: rrset to add.
 504  * @return false on failure (malloc).
 505  */
 506 static int
 507 iter_add_prepend_auth(struct module_qstate* qstate, struct iter_qstate* iq,
 508         struct ub_packed_rrset_key* rrset)
 509 {
 510         struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc(
 511                 qstate->region, sizeof(struct iter_prep_list));
 512         if(!p)
 513                 return 0;
 514         p->rrset = rrset;
 515         p->next = NULL;
 516         /* add at end */
 517         if(iq->ns_prepend_last)
 518                 iq->ns_prepend_last->next = p;
 519         else    iq->ns_prepend_list = p;
 520         iq->ns_prepend_last = p;
 521         return 1;
 522 }
 523
 524 /**
 525  * Given a CNAME response (defined as a response containing a CNAME or DNAME
 526  * that does not answer the request), process the response, modifying the
 527  * state as necessary. This follows the CNAME/DNAME chain and returns the
 528  * final query name.
 529  *
 530  * sets the new query name, after following the CNAME/DNAME chain.
 531  * @param qstate: query state.
 532  * @param iq: iterator query state.
 533  * @param msg: the response.
 534  * @param mname: returned target new query name.
 535  * @param mname_len: length of mname.
 536  * @return false on (malloc) error.
 537  */
 538 static int
 539 handle_cname_response(struct module_qstate* qstate, struct iter_qstate* iq,
 540         struct dns_msg* msg, uint8_t** mname, size_t* mname_len)
 541 {
 542         size_t i;
 543         /* Start with the (current) qname. */
 544         *mname = iq->qchase.qname;
 545         *mname_len = iq->qchase.qname_len;
 546
 547         /* Iterate over the ANSWER rrsets in order, looking for CNAMEs and
 548          * DNAMES. */
 549         for(i=0; i<msg->rep->an_numrrsets; i++) {
 550                 struct ub_packed_rrset_key* r = msg->rep->rrsets[i];
 551                 /* If there is a (relevant) DNAME, add it to the list.
 552                  * We always expect there to be CNAME that was generated
 553                  * by this DNAME following, so we don't process the DNAME
 554                  * directly.  */
 555                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_DNAME &&
 556                         dname_strict_subdomain_c(*mname, r->rk.dname) &&
 557                         !iter_find_rrset_in_prepend_answer(iq, r)) {
 558                         if(!iter_add_prepend_answer(qstate, iq, r))
 559                                 return 0;
 560                         continue;
 561                 }
 562
 563                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_CNAME &&
 564                         query_dname_compare(*mname, r->rk.dname) == 0 &&
 565                         !iter_find_rrset_in_prepend_answer(iq, r)) {
 566                         /* Add this relevant CNAME rrset to the prepend list.*/
 567                         if(!iter_add_prepend_answer(qstate, iq, r))
 568                                 return 0;
 569                         get_cname_target(r, mname, mname_len);
 570                 }
 571
 572                 /* Other rrsets in the section are ignored. */
 573         }
 574         /* add authority rrsets to authority prepend, for wildcarded CNAMEs */
 575         for(i=msg->rep->an_numrrsets; i<msg->rep->an_numrrsets +
 576                 msg->rep->ns_numrrsets; i++) {
 577                 struct ub_packed_rrset_key* r = msg->rep->rrsets[i];
 578                 /* only add NSEC/NSEC3, as they may be needed for validation */
 579                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC ||
 580                         ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC3) {
 581                         if(!iter_add_prepend_auth(qstate, iq, r))
 582                                 return 0;
 583                 }
 584         }
 585         return 1;
 586 }
 587
 588 /** see if last resort is possible - does config allow queries to parent */
 589 static int
 590 can_have_last_resort(struct module_env* env, uint8_t* nm, size_t nmlen,
 591         uint16_t qclass, struct delegpt** retdp)
 592 {
 593         struct delegpt* fwddp;
 594         struct iter_hints_stub* stub;
 595         int labs = dname_count_labels(nm);
 596         /* do not process a last resort (the parent side) if a stub
 597          * or forward is configured, because we do not want to go 'above'
 598          * the configured servers */
 599         if(!dname_is_root(nm) && (stub = (struct iter_hints_stub*)
 600                 name_tree_find(&env->hints->tree, nm, nmlen, labs, qclass)) &&
 601                 /* has_parent side is turned off for stub_first, where we
 602                  * are allowed to go to the parent */
 603                 stub->dp->has_parent_side_NS) {
 604                 if(retdp) *retdp = stub->dp;
 605                 return 0;
 606         }
 607         if((fwddp = forwards_find(env->fwds, nm, qclass)) &&
 608                 /* has_parent_side is turned off for forward_first, where
 609                  * we are allowed to go to the parent */
 610                 fwddp->has_parent_side_NS) {
 611                 if(retdp) *retdp = fwddp;
 612                 return 0;
 613         }
 614         return 1;
 615 }
 616
 617 /** see if target name is caps-for-id whitelisted */
 618 static int
 619 is_caps_whitelisted(struct iter_env* ie, struct iter_qstate* iq)
 620 {
 621         if(!ie->caps_white) return 0; /* no whitelist, or no capsforid */
 622         return name_tree_lookup(ie->caps_white, iq->qchase.qname,
 623                 iq->qchase.qname_len, dname_count_labels(iq->qchase.qname),
 624                 iq->qchase.qclass) != NULL;
 625 }
 626
 627 /** create target count structure for this query */
 628 static void
 629 target_count_create(struct iter_qstate* iq)
 630 {
 631         if(!iq->target_count) {
 632                 iq->target_count = (int*)calloc(3, sizeof(int));
 633                 /* if calloc fails we simply do not track this number */
 634                 if(iq->target_count)
 635                         iq->target_count[0] = 1;
 636         }
 637 }
 638
 639 static void
 640 target_count_increase(struct iter_qstate* iq, int num)
 641 {
 642         target_count_create(iq);
 643         if(iq->target_count)
 644                 iq->target_count[1] += num;
 645         iq->dp_target_count++;
 646 }
 647
 648 static void
 649 target_count_increase_nx(struct iter_qstate* iq, int num)
 650 {
 651         target_count_create(iq);
 652         if(iq->target_count)
 653                 iq->target_count[2] += num;
 654 }
 655
 656 /**
 657  * Generate a subrequest.
 658  * Generate a local request event. Local events are tied to this module, and
 659  * have a corresponding (first tier) event that is waiting for this event to
 660  * resolve to continue.
 661  *
 662  * @param qname The query name for this request.
 663  * @param qnamelen length of qname
 664  * @param qtype The query type for this request.
 665  * @param qclass The query class for this request.
 666  * @param qstate The event that is generating this event.
 667  * @param id: module id.
 668  * @param iq: The iterator state that is generating this event.
 669  * @param initial_state The initial response state (normally this
 670  *          is QUERY_RESP_STATE, unless it is known that the request won't
 671  *          need iterative processing
 672  * @param finalstate The final state for the response to this request.
 673  * @param subq_ret: if newly allocated, the subquerystate, or NULL if it does
 674  *      not need initialisation.
 675  * @param v: if true, validation is done on the subquery.
 676  * @param detached: true if this qstate should not attach to the subquery
 677  * @return false on error (malloc).
 678  */
 679 static int
 680 generate_sub_request(uint8_t* qname, size_t qnamelen, uint16_t qtype,
 681         uint16_t qclass, struct module_qstate* qstate, int id,
 682         struct iter_qstate* iq, enum iter_state initial_state,
 683         enum iter_state finalstate, struct module_qstate** subq_ret, int v,
 684         int detached)
 685 {
 686         struct module_qstate* subq = NULL;
 687         struct iter_qstate* subiq = NULL;
 688         uint16_t qflags = 0; /* OPCODE QUERY, no flags */
 689         struct query_info qinf;
 690         int prime = (finalstate == PRIME_RESP_STATE)?1:0;
 691         int valrec = 0;
 692         qinf.qname = qname;
 693         qinf.qname_len = qnamelen;
 694         qinf.qtype = qtype;
 695         qinf.qclass = qclass;
 696         qinf.local_alias = NULL;
 697
 698         /* RD should be set only when sending the query back through the INIT
 699          * state. */
 700         if(initial_state == INIT_REQUEST_STATE)
 701                 qflags |= BIT_RD;
 702         /* We set the CD flag so we can send this through the "head" of
 703          * the resolution chain, which might have a validator. We are
 704          * uninterested in validating things not on the direct resolution
 705          * path.  */
 706         if(!v) {
 707                 qflags |= BIT_CD;
 708                 valrec = 1;
 709         }
 710
 711         if(detached) {
 712                 struct mesh_state* sub = NULL;
 713                 fptr_ok(fptr_whitelist_modenv_add_sub(
 714                         qstate->env->add_sub));
 715                 if(!(*qstate->env->add_sub)(qstate, &qinf,
 716                         qflags, prime, valrec, &subq, &sub)){
 717                         return 0;
 718                 }
 719         }
 720         else {
 721                 /* attach subquery, lookup existing or make a new one */
 722                 fptr_ok(fptr_whitelist_modenv_attach_sub(
 723                         qstate->env->attach_sub));
 724                 if(!(*qstate->env->attach_sub)(qstate, &qinf, qflags, prime,
 725                         valrec, &subq)) {
 726                         return 0;
 727                 }
 728         }
 729         *subq_ret = subq;
 730         if(subq) {
 731                 /* initialise the new subquery */
 732                 subq->curmod = id;
 733                 subq->ext_state[id] = module_state_initial;
 734                 subq->minfo[id] = regional_alloc(subq->region,
 735                         sizeof(struct iter_qstate));
 736                 if(!subq->minfo[id]) {
 737                         log_err("init subq: out of memory");
 738                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 739                                 qstate->env->kill_sub));
 740                         (*qstate->env->kill_sub)(subq);
 741                         return 0;
 742                 }
 743                 subiq = (struct iter_qstate*)subq->minfo[id];
 744                 memset(subiq, 0, sizeof(*subiq));
 745                 subiq->num_target_queries = 0;
 746                 target_count_create(iq);
 747                 subiq->target_count = iq->target_count;
 748                 if(iq->target_count)
 749                         iq->target_count[0] ++; /* extra reference */
 750                 subiq->dp_target_count = 0;
 751                 subiq->num_current_queries = 0;
 752                 subiq->depth = iq->depth+1;
 753                 outbound_list_init(&subiq->outlist);
 754                 subiq->state = initial_state;
 755                 subiq->final_state = finalstate;
 756                 subiq->qchase = subq->qinfo;
 757                 subiq->chase_flags = subq->query_flags;
 758                 subiq->refetch_glue = 0;
 759                 if(qstate->env->cfg->qname_minimisation)
 760                         subiq->minimisation_state = INIT_MINIMISE_STATE;
 761                 else
 762                         subiq->minimisation_state = DONOT_MINIMISE_STATE;
 763                 memset(&subiq->qinfo_out, 0, sizeof(struct query_info));
 764         }
 765         return 1;
 766 }
 767
 768 /**
 769  * Generate and send a root priming request.
 770  * @param qstate: the qtstate that triggered the need to prime.
 771  * @param iq: iterator query state.
 772  * @param id: module id.
 773  * @param qclass: the class to prime.
 774  * @return 0 on failure
 775  */
 776 static int
 777 prime_root(struct module_qstate* qstate, struct iter_qstate* iq, int id,
 778         uint16_t qclass)
 779 {
 780         struct delegpt* dp;
 781         struct module_qstate* subq;
 782         verbose(VERB_DETAIL, "priming . %s NS",
 783                 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)?
 784                 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)->name:"??");
 785         dp = hints_lookup_root(qstate->env->hints, qclass);
 786         if(!dp) {
 787                 verbose(VERB_ALGO, "Cannot prime due to lack of hints");
 788                 return 0;
 789         }
 790         /* Priming requests start at the QUERYTARGETS state, skipping
 791          * the normal INIT state logic (which would cause an infloop). */
 792         if(!generate_sub_request((uint8_t*)"\000", 1, LDNS_RR_TYPE_NS,
 793                 qclass, qstate, id, iq, QUERYTARGETS_STATE, PRIME_RESP_STATE,
 794                 &subq, 0, 0)) {
 795                 verbose(VERB_ALGO, "could not prime root");
 796                 return 0;
 797         }
 798         if(subq) {
 799                 struct iter_qstate* subiq =
 800                         (struct iter_qstate*)subq->minfo[id];
 801                 /* Set the initial delegation point to the hint.
 802                  * copy dp, it is now part of the root prime query.
 803                  * dp was part of in the fixed hints structure. */
 804                 subiq->dp = delegpt_copy(dp, subq->region);
 805                 if(!subiq->dp) {
 806                         log_err("out of memory priming root, copydp");
 807                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 808                                 qstate->env->kill_sub));
 809                         (*qstate->env->kill_sub)(subq);
 810                         return 0;
 811                 }
 812                 /* there should not be any target queries. */
 813                 subiq->num_target_queries = 0;
 814                 subiq->dnssec_expected = iter_indicates_dnssec(
 815                         qstate->env, subiq->dp, NULL, subq->qinfo.qclass);
 816         }
 817
 818         /* this module stops, our submodule starts, and does the query. */
 819         qstate->ext_state[id] = module_wait_subquery;
 820         return 1;
 821 }
 822
 823 /**
 824  * Generate and process a stub priming request. This method tests for the
 825  * need to prime a stub zone, so it is safe to call for every request.
 826  *
 827  * @param qstate: the qtstate that triggered the need to prime.
 828  * @param iq: iterator query state.
 829  * @param id: module id.
 830  * @param qname: request name.
 831  * @param qclass: request class.
 832  * @return true if a priming subrequest was made, false if not. The will only
 833  *         issue a priming request if it detects an unprimed stub.
 834  *         Uses value of 2 to signal during stub-prime in root-prime situation
 835  *         that a noprime-stub is available and resolution can continue.
 836  */
 837 static int
 838 prime_stub(struct module_qstate* qstate, struct iter_qstate* iq, int id,
 839         uint8_t* qname, uint16_t qclass)
 840 {
 841         /* Lookup the stub hint. This will return null if the stub doesn't
 842          * need to be re-primed. */
 843         struct iter_hints_stub* stub;
 844         struct delegpt* stub_dp;
 845         struct module_qstate* subq;
 846
 847         if(!qname) return 0;
 848         stub = hints_lookup_stub(qstate->env->hints, qname, qclass, iq->dp);
 849         /* The stub (if there is one) does not need priming. */
 850         if(!stub)
 851                 return 0;
 852         stub_dp = stub->dp;
 853         /* if we have an auth_zone dp, and stub is equal, don't prime stub
 854          * yet, unless we want to fallback and avoid the auth_zone */
 855         if(!iq->auth_zone_avoid && iq->dp && iq->dp->auth_dp &&
 856                 query_dname_compare(iq->dp->name, stub_dp->name) == 0)
 857                 return 0;
 858
 859         /* is it a noprime stub (always use) */
 860         if(stub->noprime) {
 861                 int r = 0;
 862                 if(iq->dp == NULL) r = 2;
 863                 /* copy the dp out of the fixed hints structure, so that
 864                  * it can be changed when servicing this query */
 865                 iq->dp = delegpt_copy(stub_dp, qstate->region);
 866                 if(!iq->dp) {
 867                         log_err("out of memory priming stub");
 868                         errinf(qstate, "malloc failure, priming stub");
 869                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 870                         return 1; /* return 1 to make module stop, with error */
 871                 }
 872                 log_nametypeclass(VERB_DETAIL, "use stub", stub_dp->name,
 873                         LDNS_RR_TYPE_NS, qclass);
 874                 return r;
 875         }
 876
 877         /* Otherwise, we need to (re)prime the stub. */
 878         log_nametypeclass(VERB_DETAIL, "priming stub", stub_dp->name,
 879                 LDNS_RR_TYPE_NS, qclass);
 880
 881         /* Stub priming events start at the QUERYTARGETS state to avoid the
 882          * redundant INIT state processing. */
 883         if(!generate_sub_request(stub_dp->name, stub_dp->namelen,
 884                 LDNS_RR_TYPE_NS, qclass, qstate, id, iq,
 885                 QUERYTARGETS_STATE, PRIME_RESP_STATE, &subq, 0, 0)) {
 886                 verbose(VERB_ALGO, "could not prime stub");
 887                 errinf(qstate, "could not generate lookup for stub prime");
 888                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 889                 return 1; /* return 1 to make module stop, with error */
 890         }
 891         if(subq) {
 892                 struct iter_qstate* subiq =
 893                         (struct iter_qstate*)subq->minfo[id];
 894
 895                 /* Set the initial delegation point to the hint. */
 896                 /* make copy to avoid use of stub dp by different qs/threads */
 897                 subiq->dp = delegpt_copy(stub_dp, subq->region);
 898                 if(!subiq->dp) {
 899                         log_err("out of memory priming stub, copydp");
 900                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 901                                 qstate->env->kill_sub));
 902                         (*qstate->env->kill_sub)(subq);
 903                         errinf(qstate, "malloc failure, in stub prime");
 904                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 905                         return 1; /* return 1 to make module stop, with error */
 906                 }
 907                 /* there should not be any target queries -- although there
 908                  * wouldn't be anyway, since stub hints never have
 909                  * missing targets. */
 910                 subiq->num_target_queries = 0;
 911                 subiq->wait_priming_stub = 1;
 912                 subiq->dnssec_expected = iter_indicates_dnssec(
 913                         qstate->env, subiq->dp, NULL, subq->qinfo.qclass);
 914         }
 915
 916         /* this module stops, our submodule starts, and does the query. */
 917         qstate->ext_state[id] = module_wait_subquery;
 918         return 1;
 919 }
 920
 921 /**
 922  * Generate a delegation point for an auth zone (unless cached dp is better)
 923  * false on alloc failure.
 924  */
 925 static int
 926 auth_zone_delegpt(struct module_qstate* qstate, struct iter_qstate* iq,
 927         uint8_t* delname, size_t delnamelen)
 928 {
 929         struct auth_zone* z;
 930         if(iq->auth_zone_avoid)
 931                 return 1;
 932         if(!delname) {
 933                 delname = iq->qchase.qname;
 934                 delnamelen = iq->qchase.qname_len;
 935         }
 936         lock_rw_rdlock(&qstate->env->auth_zones->lock);
 937         z = auth_zones_find_zone(qstate->env->auth_zones, delname, delnamelen,
 938                 qstate->qinfo.qclass);
 939         if(!z) {
 940                 lock_rw_unlock(&qstate->env->auth_zones->lock);
 941                 return 1;
 942         }
 943         lock_rw_rdlock(&z->lock);
 944         lock_rw_unlock(&qstate->env->auth_zones->lock);
 945         if(z->for_upstream) {
 946                 if(iq->dp && query_dname_compare(z->name, iq->dp->name) == 0
 947                         && iq->dp->auth_dp && qstate->blacklist &&
 948                         z->fallback_enabled) {
 949                         /* cache is blacklisted and fallback, and we
 950                          * already have an auth_zone dp */
 951                         if(verbosity>=VERB_ALGO) {
 952                                 char buf[255+1];
 953                                 dname_str(z->name, buf);
 954                                 verbose(VERB_ALGO, "auth_zone %s "
 955                                   "fallback because cache blacklisted",
 956                                   buf);
 957                         }
 958                         lock_rw_unlock(&z->lock);
 959                         iq->dp = NULL;
 960                         return 1;
 961                 }
 962                 if(iq->dp==NULL || dname_subdomain_c(z->name, iq->dp->name)) {
 963                         struct delegpt* dp;
 964                         if(qstate->blacklist && z->fallback_enabled) {
 965                                 /* cache is blacklisted because of a DNSSEC
 966                                  * validation failure, and the zone allows
 967                                  * fallback to the internet, query there. */
 968                                 if(verbosity>=VERB_ALGO) {
 969                                         char buf[255+1];
 970                                         dname_str(z->name, buf);
 971                                         verbose(VERB_ALGO, "auth_zone %s "
 972                                           "fallback because cache blacklisted",
 973                                           buf);
 974                                 }
 975                                 lock_rw_unlock(&z->lock);
 976                                 return 1;
 977                         }
 978                         dp = (struct delegpt*)regional_alloc_zero(
 979                                 qstate->region, sizeof(*dp));
 980                         if(!dp) {
 981                                 log_err("alloc failure");
 982                                 if(z->fallback_enabled) {
 983                                         lock_rw_unlock(&z->lock);
 984                                         return 1; /* just fallback */
 985                                 }
 986                                 lock_rw_unlock(&z->lock);
 987                                 errinf(qstate, "malloc failure");
 988                                 return 0;
 989                         }
 990                         dp->name = regional_alloc_init(qstate->region,
 991                                 z->name, z->namelen);
 992                         if(!dp->name) {
 993                                 log_err("alloc failure");
 994                                 if(z->fallback_enabled) {
 995                                         lock_rw_unlock(&z->lock);
 996                                         return 1; /* just fallback */
 997                                 }
 998                                 lock_rw_unlock(&z->lock);
 999                                 errinf(qstate, "malloc failure");
1000                                 return 0;
1001                         }
1002                         dp->namelen = z->namelen;
1003                         dp->namelabs = z->namelabs;
1004                         dp->auth_dp = 1;
1005                         iq->dp = dp;
1006                 }
1007         }
1008
1009         lock_rw_unlock(&z->lock);
1010         return 1;
1011 }
1012
1013 /**
1014  * Generate A and AAAA checks for glue that is in-zone for the referral
1015  * we just got to obtain authoritative information on the addresses.
1016  *
1017  * @param qstate: the qtstate that triggered the need to prime.
1018  * @param iq: iterator query state.
1019  * @param id: module id.
1020  */
1021 static void
1022 generate_a_aaaa_check(struct module_qstate* qstate, struct iter_qstate* iq,
1023         int id)
1024 {
1025         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
1026         struct module_qstate* subq;
1027         size_t i;
1028         struct reply_info* rep = iq->response->rep;
1029         struct ub_packed_rrset_key* s;
1030         log_assert(iq->dp);
1031
1032         if(iq->depth == ie->max_dependency_depth)
1033                 return;
1034         /* walk through additional, and check if in-zone,
1035          * only relevant A, AAAA are left after scrub anyway */
1036         for(i=rep->an_numrrsets+rep->ns_numrrsets; i<rep->rrset_count; i++) {
1037                 s = rep->rrsets[i];
1038                 /* check *ALL* addresses that are transmitted in additional*/
1039                 /* is it an address ? */
1040                 if( !(ntohs(s->rk.type)==LDNS_RR_TYPE_A ||
1041                         ntohs(s->rk.type)==LDNS_RR_TYPE_AAAA)) {
1042                         continue;
1043                 }
1044                 /* is this query the same as the A/AAAA check for it */
1045                 if(qstate->qinfo.qtype == ntohs(s->rk.type) &&
1046                         qstate->qinfo.qclass == ntohs(s->rk.rrset_class) &&
1047                         query_dname_compare(qstate->qinfo.qname,
1048                                 s->rk.dname)==0 &&
1049                         (qstate->query_flags&BIT_RD) &&
1050                         !(qstate->query_flags&BIT_CD))
1051                         continue;
1052
1053                 /* generate subrequest for it */
1054                 log_nametypeclass(VERB_ALGO, "schedule addr fetch",
1055                         s->rk.dname, ntohs(s->rk.type),
1056                         ntohs(s->rk.rrset_class));
1057                 if(!generate_sub_request(s->rk.dname, s->rk.dname_len,
1058                         ntohs(s->rk.type), ntohs(s->rk.rrset_class),
1059                         qstate, id, iq,
1060                         INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1, 0)) {
1061                         verbose(VERB_ALGO, "could not generate addr check");
1062                         return;
1063                 }
1064                 /* ignore subq - not need for more init */
1065         }
1066 }
1067
1068 /**
1069  * Generate a NS check request to obtain authoritative information
1070  * on an NS rrset.
1071  *
1072  * @param qstate: the qtstate that triggered the need to prime.
1073  * @param iq: iterator query state.
1074  * @param id: module id.
1075  */
1076 static void
1077 generate_ns_check(struct module_qstate* qstate, struct iter_qstate* iq, int id)
1078 {
1079         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
1080         struct module_qstate* subq;
1081         log_assert(iq->dp);
1082
1083         if(iq->depth == ie->max_dependency_depth)
1084                 return;
1085         if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen,
1086                 iq->qchase.qclass, NULL))
1087                 return;
1088         /* is this query the same as the nscheck? */
1089         if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS &&
1090                 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 &&
1091                 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){
1092                 /* spawn off A, AAAA queries for in-zone glue to check */
1093                 generate_a_aaaa_check(qstate, iq, id);
1094                 return;
1095         }
1096         /* no need to get the NS record for DS, it is above the zonecut */
1097         if(qstate->qinfo.qtype == LDNS_RR_TYPE_DS)
1098                 return;
1099
1100         log_nametypeclass(VERB_ALGO, "schedule ns fetch",
1101                 iq->dp->name, LDNS_RR_TYPE_NS, iq->qchase.qclass);
1102         if(!generate_sub_request(iq->dp->name, iq->dp->namelen,
1103                 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
1104                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1, 0)) {
1105                 verbose(VERB_ALGO, "could not generate ns check");
1106                 return;
1107         }
1108         if(subq) {
1109                 struct iter_qstate* subiq =
1110                         (struct iter_qstate*)subq->minfo[id];
1111
1112                 /* make copy to avoid use of stub dp by different qs/threads */
1113                 /* refetch glue to start higher up the tree */
1114                 subiq->refetch_glue = 1;
1115                 subiq->dp = delegpt_copy(iq->dp, subq->region);
1116                 if(!subiq->dp) {
1117                         log_err("out of memory generating ns check, copydp");
1118                         fptr_ok(fptr_whitelist_modenv_kill_sub(
1119                                 qstate->env->kill_sub));
1120                         (*qstate->env->kill_sub)(subq);
1121                         return;
1122                 }
1123         }
1124 }
1125
1126 /**
1127  * Generate a DNSKEY prefetch query to get the DNSKEY for the DS record we
1128  * just got in a referral (where we have dnssec_expected, thus have trust
1129  * anchors above it).  Note that right after calling this routine the
1130  * iterator detached subqueries (because of following the referral), and thus
1131  * the DNSKEY query becomes detached, its return stored in the cache for
1132  * later lookup by the validator.  This cache lookup by the validator avoids
1133  * the roundtrip incurred by the DNSKEY query.  The DNSKEY query is now
1134  * performed at about the same time the original query is sent to the domain,
1135  * thus the two answers are likely to be returned at about the same time,
1136  * saving a roundtrip from the validated lookup.
1137  *
1138  * @param qstate: the qtstate that triggered the need to prime.
1139  * @param iq: iterator query state.
1140  * @param id: module id.
1141  */
1142 static void
1143 generate_dnskey_prefetch(struct module_qstate* qstate,
1144         struct iter_qstate* iq, int id)
1145 {
1146         struct module_qstate* subq;
1147         log_assert(iq->dp);
1148
1149         /* is this query the same as the prefetch? */
1150         if(qstate->qinfo.qtype == LDNS_RR_TYPE_DNSKEY &&
1151                 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 &&
1152                 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){
1153                 return;
1154         }
1155
1156         /* if the DNSKEY is in the cache this lookup will stop quickly */
1157         log_nametypeclass(VERB_ALGO, "schedule dnskey prefetch",
1158                 iq->dp->name, LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass);
1159         if(!generate_sub_request(iq->dp->name, iq->dp->namelen,
1160                 LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass, qstate, id, iq,
1161                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0)) {
1162                 /* we'll be slower, but it'll work */
1163                 verbose(VERB_ALGO, "could not generate dnskey prefetch");
1164                 return;
1165         }
1166         if(subq) {
1167                 struct iter_qstate* subiq =
1168                         (struct iter_qstate*)subq->minfo[id];
1169                 /* this qstate has the right delegation for the dnskey lookup*/
1170                 /* make copy to avoid use of stub dp by different qs/threads */
1171                 subiq->dp = delegpt_copy(iq->dp, subq->region);
1172                 /* if !subiq->dp, it'll start from the cache, no problem */
1173         }
1174 }
1175
1176 /**
1177  * See if the query needs forwarding.
1178  *
1179  * @param qstate: query state.
1180  * @param iq: iterator query state.
1181  * @return true if the request is forwarded, false if not.
1182  *      If returns true but, iq->dp is NULL then a malloc failure occurred.
1183  */
1184 static int
1185 forward_request(struct module_qstate* qstate, struct iter_qstate* iq)
1186 {
1187         struct delegpt* dp;
1188         uint8_t* delname = iq->qchase.qname;
1189         size_t delnamelen = iq->qchase.qname_len;
1190         if(iq->refetch_glue && iq->dp) {
1191                 delname = iq->dp->name;
1192                 delnamelen = iq->dp->namelen;
1193         }
1194         /* strip one label off of DS query to lookup higher for it */
1195         if( (iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue)
1196                 && !dname_is_root(iq->qchase.qname))
1197                 dname_remove_label(&delname, &delnamelen);
1198         dp = forwards_lookup(qstate->env->fwds, delname, iq->qchase.qclass);
1199         if(!dp)
1200                 return 0;
1201         /* send recursion desired to forward addr */
1202         iq->chase_flags |= BIT_RD;
1203         iq->dp = delegpt_copy(dp, qstate->region);
1204         /* iq->dp checked by caller */
1205         verbose(VERB_ALGO, "forwarding request");
1206         return 1;
1207 }
1208
1209 /**
1210  * Process the initial part of the request handling. This state roughly
1211  * corresponds to resolver algorithms steps 1 (find answer in cache) and 2
1212  * (find the best servers to ask).
1213  *
1214  * Note that all requests start here, and query restarts revisit this state.
1215  *
1216  * This state either generates: 1) a response, from cache or error, 2) a
1217  * priming event, or 3) forwards the request to the next state (init2,
1218  * generally).
1219  *
1220  * @param qstate: query state.
1221  * @param iq: iterator query state.
1222  * @param ie: iterator shared global environment.
1223  * @param id: module id.
1224  * @return true if the event needs more request processing immediately,
1225  *         false if not.
1226  */
1227 static int
1228 processInitRequest(struct module_qstate* qstate, struct iter_qstate* iq,
1229         struct iter_env* ie, int id)
1230 {
1231         uint8_t* delname;
1232         size_t delnamelen;
1233         struct dns_msg* msg = NULL;
1234
1235         log_query_info(VERB_DETAIL, "resolving", &qstate->qinfo);
1236         /* check effort */
1237
1238         /* We enforce a maximum number of query restarts. This is primarily a
1239          * cheap way to prevent CNAME loops. */
1240         if(iq->query_restart_count > MAX_RESTART_COUNT) {
1241                 verbose(VERB_QUERY, "request has exceeded the maximum number"
1242                         " of query restarts with %d", iq->query_restart_count);
1243                 errinf(qstate, "request has exceeded the maximum number "
1244                         "restarts (eg. indirections)");
1245                 if(iq->qchase.qname)
1246                         errinf_dname(qstate, "stop at", iq->qchase.qname);
1247                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1248         }
1249
1250         /* We enforce a maximum recursion/dependency depth -- in general,
1251          * this is unnecessary for dependency loops (although it will
1252          * catch those), but it provides a sensible limit to the amount
1253          * of work required to answer a given query. */
1254         verbose(VERB_ALGO, "request has dependency depth of %d", iq->depth);
1255         if(iq->depth > ie->max_dependency_depth) {
1256                 verbose(VERB_QUERY, "request has exceeded the maximum "
1257                         "dependency depth with depth of %d", iq->depth);
1258                 errinf(qstate, "request has exceeded the maximum dependency "
1259                         "depth (eg. nameserver lookup recursion)");
1260                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1261         }
1262
1263         /* If the request is qclass=ANY, setup to generate each class */
1264         if(qstate->qinfo.qclass == LDNS_RR_CLASS_ANY) {
1265                 iq->qchase.qclass = 0;
1266                 return next_state(iq, COLLECT_CLASS_STATE);
1267         }
1268
1269         /*
1270          * If we are restricted by a forward-zone or a stub-zone, we
1271          * can't re-fetch glue for this delegation point.
1272          * we won’t try to re-fetch glue if the iq->dp is null.
1273          */
1274         if (iq->refetch_glue &&
1275                 iq->dp &&
1276                 !can_have_last_resort(qstate->env, iq->dp->name,
1277                      iq->dp->namelen, iq->qchase.qclass, NULL)) {
1278             iq->refetch_glue = 0;
1279         }
1280
1281         /* Resolver Algorithm Step 1 -- Look for the answer in local data. */
1282
1283         /* This either results in a query restart (CNAME cache response), a
1284          * terminating response (ANSWER), or a cache miss (null). */
1285
1286         if (iter_stub_fwd_no_cache(qstate, &iq->qchase)) {
1287                 /* Asked to not query cache. */
1288                 verbose(VERB_ALGO, "no-cache set, going to the network");
1289                 qstate->no_cache_lookup = 1;
1290                 qstate->no_cache_store = 1;
1291                 msg = NULL;
1292         } else if(qstate->blacklist) {
1293                 /* if cache, or anything else, was blacklisted then
1294                  * getting older results from cache is a bad idea, no cache */
1295                 verbose(VERB_ALGO, "cache blacklisted, going to the network");
1296                 msg = NULL;
1297         } else if(!qstate->no_cache_lookup) {
1298                 msg = dns_cache_lookup(qstate->env, iq->qchase.qname,
1299                         iq->qchase.qname_len, iq->qchase.qtype,
1300                         iq->qchase.qclass, qstate->query_flags,
1301                         qstate->region, qstate->env->scratch, 0);
1302                 if(!msg && qstate->env->neg_cache &&
1303                         iter_qname_indicates_dnssec(qstate->env, &iq->qchase)) {
1304                         /* lookup in negative cache; may result in
1305                          * NOERROR/NODATA or NXDOMAIN answers that need validation */
1306                         msg = val_neg_getmsg(qstate->env->neg_cache, &iq->qchase,
1307                                 qstate->region, qstate->env->rrset_cache,
1308                                 qstate->env->scratch_buffer,
1309                                 *qstate->env->now, 1/*add SOA*/, NULL,
1310                                 qstate->env->cfg);
1311                 }
1312                 /* item taken from cache does not match our query name, thus
1313                  * security needs to be re-examined later */
1314                 if(msg && query_dname_compare(qstate->qinfo.qname,
1315                         iq->qchase.qname) != 0)
1316                         msg->rep->security = sec_status_unchecked;
1317         }
1318         if(msg) {
1319                 /* handle positive cache response */
1320                 enum response_type type = response_type_from_cache(msg,
1321                         &iq->qchase);
1322                 if(verbosity >= VERB_ALGO) {
1323                         log_dns_msg("msg from cache lookup", &msg->qinfo,
1324                                 msg->rep);
1325                         verbose(VERB_ALGO, "msg ttl is %d, prefetch ttl %d",
1326                                 (int)msg->rep->ttl,
1327                                 (int)msg->rep->prefetch_ttl);
1328                 }
1329
1330                 if(type == RESPONSE_TYPE_CNAME) {
1331                         uint8_t* sname = 0;
1332                         size_t slen = 0;
1333                         verbose(VERB_ALGO, "returning CNAME response from "
1334                                 "cache");
1335                         if(!handle_cname_response(qstate, iq, msg,
1336                                 &sname, &slen)) {
1337                                 errinf(qstate, "failed to prepend CNAME "
1338                                         "components, malloc failure");
1339                                 return error_response(qstate, id,
1340                                         LDNS_RCODE_SERVFAIL);
1341                         }
1342                         iq->qchase.qname = sname;
1343                         iq->qchase.qname_len = slen;
1344                         /* This *is* a query restart, even if it is a cheap
1345                          * one. */
1346                         iq->dp = NULL;
1347                         iq->refetch_glue = 0;
1348                         iq->query_restart_count++;
1349                         iq->sent_count = 0;
1350                         iq->dp_target_count = 0;
1351                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1352                         if(qstate->env->cfg->qname_minimisation)
1353                                 iq->minimisation_state = INIT_MINIMISE_STATE;
1354                         return next_state(iq, INIT_REQUEST_STATE);
1355                 }
1356
1357                 /* if from cache, NULL, else insert 'cache IP' len=0 */
1358                 if(qstate->reply_origin)
1359                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1360                 if(FLAGS_GET_RCODE(msg->rep->flags) == LDNS_RCODE_SERVFAIL)
1361                         errinf(qstate, "SERVFAIL in cache");
1362                 /* it is an answer, response, to final state */
1363                 verbose(VERB_ALGO, "returning answer from cache.");
1364                 iq->response = msg;
1365                 return final_state(iq);
1366         }
1367
1368         /* attempt to forward the request */
1369         if(forward_request(qstate, iq))
1370         {
1371                 if(!iq->dp) {
1372                         log_err("alloc failure for forward dp");
1373                         errinf(qstate, "malloc failure for forward zone");
1374                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1375                 }
1376                 iq->refetch_glue = 0;
1377                 iq->minimisation_state = DONOT_MINIMISE_STATE;
1378                 /* the request has been forwarded.
1379                  * forwarded requests need to be immediately sent to the
1380                  * next state, QUERYTARGETS. */
1381                 return next_state(iq, QUERYTARGETS_STATE);
1382         }
1383
1384         /* Resolver Algorithm Step 2 -- find the "best" servers. */
1385
1386         /* first, adjust for DS queries. To avoid the grandparent problem,
1387          * we just look for the closest set of server to the parent of qname.
1388          * When re-fetching glue we also need to ask the parent.
1389          */
1390         if(iq->refetch_glue) {
1391                 if(!iq->dp) {
1392                         log_err("internal or malloc fail: no dp for refetch");
1393                         errinf(qstate, "malloc failure, for delegation info");
1394                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1395                 }
1396                 delname = iq->dp->name;
1397                 delnamelen = iq->dp->namelen;
1398         } else {
1399                 delname = iq->qchase.qname;
1400                 delnamelen = iq->qchase.qname_len;
1401         }
1402         if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue ||
1403            (iq->qchase.qtype == LDNS_RR_TYPE_NS && qstate->prefetch_leeway
1404            && can_have_last_resort(qstate->env, delname, delnamelen, iq->qchase.qclass, NULL))) {
1405                 /* remove first label from delname, root goes to hints,
1406                  * but only to fetch glue, not for qtype=DS. */
1407                 /* also when prefetching an NS record, fetch it again from
1408                  * its parent, just as if it expired, so that you do not
1409                  * get stuck on an older nameserver that gives old NSrecords */
1410                 if(dname_is_root(delname) && (iq->refetch_glue ||
1411                         (iq->qchase.qtype == LDNS_RR_TYPE_NS &&
1412                         qstate->prefetch_leeway)))
1413                         delname = NULL; /* go to root priming */
1414                 else    dname_remove_label(&delname, &delnamelen);
1415         }
1416         /* delname is the name to lookup a delegation for. If NULL rootprime */
1417         while(1) {
1418
1419                 /* Lookup the delegation in the cache. If null, then the
1420                  * cache needs to be primed for the qclass. */
1421                 if(delname)
1422                      iq->dp = dns_cache_find_delegation(qstate->env, delname,
1423                         delnamelen, iq->qchase.qtype, iq->qchase.qclass,
1424                         qstate->region, &iq->deleg_msg,
1425                         *qstate->env->now+qstate->prefetch_leeway);
1426                 else iq->dp = NULL;
1427
1428                 /* If the cache has returned nothing, then we have a
1429                  * root priming situation. */
1430                 if(iq->dp == NULL) {
1431                         int r;
1432                         /* if under auth zone, no prime needed */
1433                         if(!auth_zone_delegpt(qstate, iq, delname, delnamelen))
1434                                 return error_response(qstate, id,
1435                                         LDNS_RCODE_SERVFAIL);
1436                         if(iq->dp) /* use auth zone dp */
1437                                 return next_state(iq, INIT_REQUEST_2_STATE);
1438                         /* if there is a stub, then no root prime needed */
1439                         r = prime_stub(qstate, iq, id, delname,
1440                                 iq->qchase.qclass);
1441                         if(r == 2)
1442                                 break; /* got noprime-stub-zone, continue */
1443                         else if(r)
1444                                 return 0; /* stub prime request made */
1445                         if(forwards_lookup_root(qstate->env->fwds,
1446                                 iq->qchase.qclass)) {
1447                                 /* forward zone root, no root prime needed */
1448                                 /* fill in some dp - safety belt */
1449                                 iq->dp = hints_lookup_root(qstate->env->hints,
1450                                         iq->qchase.qclass);
1451                                 if(!iq->dp) {
1452                                         log_err("internal error: no hints dp");
1453                                         errinf(qstate, "no hints for this class");
1454                                         return error_response(qstate, id,
1455                                                 LDNS_RCODE_SERVFAIL);
1456                                 }
1457                                 iq->dp = delegpt_copy(iq->dp, qstate->region);
1458                                 if(!iq->dp) {
1459                                         log_err("out of memory in safety belt");
1460                                         errinf(qstate, "malloc failure, in safety belt");
1461                                         return error_response(qstate, id,
1462                                                 LDNS_RCODE_SERVFAIL);
1463                                 }
1464                                 return next_state(iq, INIT_REQUEST_2_STATE);
1465                         }
1466                         /* Note that the result of this will set a new
1467                          * DelegationPoint based on the result of priming. */
1468                         if(!prime_root(qstate, iq, id, iq->qchase.qclass))
1469                                 return error_response(qstate, id,
1470                                         LDNS_RCODE_REFUSED);
1471
1472                         /* priming creates and sends a subordinate query, with
1473                          * this query as the parent. So further processing for
1474                          * this event will stop until reactivated by the
1475                          * results of priming. */
1476                         return 0;
1477                 }
1478                 if(!iq->ratelimit_ok && qstate->prefetch_leeway)
1479                         iq->ratelimit_ok = 1; /* allow prefetches, this keeps
1480                         otherwise valid data in the cache */
1481                 if(!iq->ratelimit_ok && infra_ratelimit_exceeded(
1482                         qstate->env->infra_cache, iq->dp->name,
1483                         iq->dp->namelen, *qstate->env->now)) {
1484                         /* and increment the rate, so that the rate for time
1485                          * now will also exceed the rate, keeping cache fresh */
1486                         (void)infra_ratelimit_inc(qstate->env->infra_cache,
1487                                 iq->dp->name, iq->dp->namelen,
1488                                 *qstate->env->now, &qstate->qinfo,
1489                                 qstate->reply);
1490                         /* see if we are passed through with slip factor */
1491                         if(qstate->env->cfg->ratelimit_factor != 0 &&
1492                                 ub_random_max(qstate->env->rnd,
1493                                     qstate->env->cfg->ratelimit_factor) == 1) {
1494                                 iq->ratelimit_ok = 1;
1495                                 log_nametypeclass(VERB_ALGO, "ratelimit allowed through for "
1496                                         "delegation point", iq->dp->name,
1497                                         LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
1498                         } else {
1499                                 lock_basic_lock(&ie->queries_ratelimit_lock);
1500                                 ie->num_queries_ratelimited++;
1501                                 lock_basic_unlock(&ie->queries_ratelimit_lock);
1502                                 log_nametypeclass(VERB_ALGO, "ratelimit exceeded with "
1503                                         "delegation point", iq->dp->name,
1504                                         LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
1505                                 qstate->was_ratelimited = 1;
1506                                 errinf(qstate, "query was ratelimited");
1507                                 errinf_dname(qstate, "for zone", iq->dp->name);
1508                                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1509                         }
1510                 }
1511
1512                 /* see if this dp not useless.
1513                  * It is useless if:
1514                  *      o all NS items are required glue.
1515                  *        or the query is for NS item that is required glue.
1516                  *      o no addresses are provided.
1517                  *      o RD qflag is on.
1518                  * Instead, go up one level, and try to get even further
1519                  * If the root was useless, use safety belt information.
1520                  * Only check cache returns, because replies for servers
1521                  * could be useless but lead to loops (bumping into the
1522                  * same server reply) if useless-checked.
1523                  */
1524                 if(iter_dp_is_useless(&qstate->qinfo, qstate->query_flags,
1525                         iq->dp)) {
1526                         struct delegpt* retdp = NULL;
1527                         if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen, iq->qchase.qclass, &retdp)) {
1528                                 if(retdp) {
1529                                         verbose(VERB_QUERY, "cache has stub "
1530                                                 "or fwd but no addresses, "
1531                                                 "fallback to config");
1532                                         iq->dp = delegpt_copy(retdp,
1533                                                 qstate->region);
1534                                         if(!iq->dp) {
1535                                                 log_err("out of memory in "
1536                                                         "stub/fwd fallback");
1537                                                 errinf(qstate, "malloc failure, for fallback to config");
1538                                                 return error_response(qstate,
1539                                                     id, LDNS_RCODE_SERVFAIL);
1540                                         }
1541                                         break;
1542                                 }
1543                                 verbose(VERB_ALGO, "useless dp "
1544                                         "but cannot go up, servfail");
1545                                 delegpt_log(VERB_ALGO, iq->dp);
1546                                 errinf(qstate, "no useful nameservers, "
1547                                         "and cannot go up");
1548                                 errinf_dname(qstate, "for zone", iq->dp->name);
1549                                 return error_response(qstate, id,
1550                                         LDNS_RCODE_SERVFAIL);
1551                         }
1552                         if(dname_is_root(iq->dp->name)) {
1553                                 /* use safety belt */
1554                                 verbose(VERB_QUERY, "Cache has root NS but "
1555                                 "no addresses. Fallback to the safety belt.");
1556                                 iq->dp = hints_lookup_root(qstate->env->hints,
1557                                         iq->qchase.qclass);
1558                                 /* note deleg_msg is from previous lookup,
1559                                  * but RD is on, so it is not used */
1560                                 if(!iq->dp) {
1561                                         log_err("internal error: no hints dp");
1562                                         return error_response(qstate, id,
1563                                                 LDNS_RCODE_REFUSED);
1564                                 }
1565                                 iq->dp = delegpt_copy(iq->dp, qstate->region);
1566                                 if(!iq->dp) {
1567                                         log_err("out of memory in safety belt");
1568                                         errinf(qstate, "malloc failure, in safety belt, for root");
1569                                         return error_response(qstate, id,
1570                                                 LDNS_RCODE_SERVFAIL);
1571                                 }
1572                                 break;
1573                         } else {
1574                                 verbose(VERB_ALGO,
1575                                         "cache delegation was useless:");
1576                                 delegpt_log(VERB_ALGO, iq->dp);
1577                                 /* go up */
1578                                 delname = iq->dp->name;
1579                                 delnamelen = iq->dp->namelen;
1580                                 dname_remove_label(&delname, &delnamelen);
1581                         }
1582                 } else break;
1583         }
1584
1585         verbose(VERB_ALGO, "cache delegation returns delegpt");
1586         delegpt_log(VERB_ALGO, iq->dp);
1587
1588         /* Otherwise, set the current delegation point and move on to the
1589          * next state. */
1590         return next_state(iq, INIT_REQUEST_2_STATE);
1591 }
1592
1593 /**
1594  * Process the second part of the initial request handling. This state
1595  * basically exists so that queries that generate root priming events have
1596  * the same init processing as ones that do not. Request events that reach
1597  * this state must have a valid currentDelegationPoint set.
1598  *
1599  * This part is primarily handling stub zone priming. Events that reach this
1600  * state must have a current delegation point.
1601  *
1602  * @param qstate: query state.
1603  * @param iq: iterator query state.
1604  * @param id: module id.
1605  * @return true if the event needs more request processing immediately,
1606  *         false if not.
1607  */
1608 static int
1609 processInitRequest2(struct module_qstate* qstate, struct iter_qstate* iq,
1610         int id)
1611 {
1612         uint8_t* delname;
1613         size_t delnamelen;
1614         log_query_info(VERB_QUERY, "resolving (init part 2): ",
1615                 &qstate->qinfo);
1616
1617         delname = iq->qchase.qname;
1618         delnamelen = iq->qchase.qname_len;
1619         if(iq->refetch_glue) {
1620                 struct iter_hints_stub* stub;
1621                 if(!iq->dp) {
1622                         log_err("internal or malloc fail: no dp for refetch");
1623                         errinf(qstate, "malloc failure, no delegation info");
1624                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1625                 }
1626                 /* Do not send queries above stub, do not set delname to dp if
1627                  * this is above stub without stub-first. */
1628                 stub = hints_lookup_stub(
1629                         qstate->env->hints, iq->qchase.qname, iq->qchase.qclass,
1630                         iq->dp);
1631                 if(!stub || !stub->dp->has_parent_side_NS ||
1632                         dname_subdomain_c(iq->dp->name, stub->dp->name)) {
1633                         delname = iq->dp->name;
1634                         delnamelen = iq->dp->namelen;
1635                 }
1636         }
1637         if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue) {
1638                 if(!dname_is_root(delname))
1639                         dname_remove_label(&delname, &delnamelen);
1640                 iq->refetch_glue = 0; /* if CNAME causes restart, no refetch */
1641         }
1642
1643         /* see if we have an auth zone to answer from, improves dp from cache
1644          * (if any dp from cache) with auth zone dp, if that is lower */
1645         if(!auth_zone_delegpt(qstate, iq, delname, delnamelen))
1646                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1647
1648         /* Check to see if we need to prime a stub zone. */
1649         if(prime_stub(qstate, iq, id, delname, iq->qchase.qclass)) {
1650                 /* A priming sub request was made */
1651                 return 0;
1652         }
1653
1654         /* most events just get forwarded to the next state. */
1655         return next_state(iq, INIT_REQUEST_3_STATE);
1656 }
1657
1658 /**
1659  * Process the third part of the initial request handling. This state exists
1660  * as a separate state so that queries that generate stub priming events
1661  * will get the tail end of the init process but not repeat the stub priming
1662  * check.
1663  *
1664  * @param qstate: query state.
1665  * @param iq: iterator query state.
1666  * @param id: module id.
1667  * @return true, advancing the event to the QUERYTARGETS_STATE.
1668  */
1669 static int
1670 processInitRequest3(struct module_qstate* qstate, struct iter_qstate* iq,
1671         int id)
1672 {
1673         log_query_info(VERB_QUERY, "resolving (init part 3): ",
1674                 &qstate->qinfo);
1675         /* if the cache reply dp equals a validation anchor or msg has DS,
1676          * then DNSSEC RRSIGs are expected in the reply */
1677         iq->dnssec_expected = iter_indicates_dnssec(qstate->env, iq->dp,
1678                 iq->deleg_msg, iq->qchase.qclass);
1679
1680         /* If the RD flag wasn't set, then we just finish with the
1681          * cached referral as the response. */
1682         if(!(qstate->query_flags & BIT_RD) && iq->deleg_msg) {
1683                 iq->response = iq->deleg_msg;
1684                 if(verbosity >= VERB_ALGO && iq->response)
1685                         log_dns_msg("no RD requested, using delegation msg",
1686                                 &iq->response->qinfo, iq->response->rep);
1687                 if(qstate->reply_origin)
1688                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1689                 return final_state(iq);
1690         }
1691         /* After this point, unset the RD flag -- this query is going to
1692          * be sent to an auth. server. */
1693         iq->chase_flags &= ~BIT_RD;
1694
1695         /* if dnssec expected, fetch key for the trust-anchor or cached-DS */
1696         if(iq->dnssec_expected && qstate->env->cfg->prefetch_key &&
1697                 !(qstate->query_flags&BIT_CD)) {
1698                 generate_dnskey_prefetch(qstate, iq, id);
1699                 fptr_ok(fptr_whitelist_modenv_detach_subs(
1700                         qstate->env->detach_subs));
1701                 (*qstate->env->detach_subs)(qstate);
1702         }
1703
1704         /* Jump to the next state. */
1705         return next_state(iq, QUERYTARGETS_STATE);
1706 }
1707
1708 /**
1709  * Given a basic query, generate a parent-side "target" query.
1710  * These are subordinate queries for missing delegation point target addresses,
1711  * for which only the parent of the delegation provides correct IP addresses.
1712  *
1713  * @param qstate: query state.
1714  * @param iq: iterator query state.
1715  * @param id: module id.
1716  * @param name: target qname.
1717  * @param namelen: target qname length.
1718  * @param qtype: target qtype (either A or AAAA).
1719  * @param qclass: target qclass.
1720  * @return true on success, false on failure.
1721  */
1722 static int
1723 generate_parentside_target_query(struct module_qstate* qstate,
1724         struct iter_qstate* iq, int id, uint8_t* name, size_t namelen,
1725         uint16_t qtype, uint16_t qclass)
1726 {
1727         struct module_qstate* subq;
1728         if(!generate_sub_request(name, namelen, qtype, qclass, qstate,
1729                 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0))
1730                 return 0;
1731         if(subq) {
1732                 struct iter_qstate* subiq =
1733                         (struct iter_qstate*)subq->minfo[id];
1734                 /* blacklist the cache - we want to fetch parent stuff */
1735                 sock_list_insert(&subq->blacklist, NULL, 0, subq->region);
1736                 subiq->query_for_pside_glue = 1;
1737                 if(dname_subdomain_c(name, iq->dp->name)) {
1738                         subiq->dp = delegpt_copy(iq->dp, subq->region);
1739                         subiq->dnssec_expected = iter_indicates_dnssec(
1740                                 qstate->env, subiq->dp, NULL,
1741                                 subq->qinfo.qclass);
1742                         subiq->refetch_glue = 1;
1743                 } else {
1744                         subiq->dp = dns_cache_find_delegation(qstate->env,
1745                                 name, namelen, qtype, qclass, subq->region,
1746                                 &subiq->deleg_msg,
1747                                 *qstate->env->now+subq->prefetch_leeway);
1748                         /* if no dp, then it's from root, refetch unneeded */
1749                         if(subiq->dp) {
1750                                 subiq->dnssec_expected = iter_indicates_dnssec(
1751                                         qstate->env, subiq->dp, NULL,
1752                                         subq->qinfo.qclass);
1753                                 subiq->refetch_glue = 1;
1754                         }
1755                 }
1756         }
1757         log_nametypeclass(VERB_QUERY, "new pside target", name, qtype, qclass);
1758         return 1;
1759 }
1760
1761 /**
1762  * Given a basic query, generate a "target" query. These are subordinate
1763  * queries for missing delegation point target addresses.
1764  *
1765  * @param qstate: query state.
1766  * @param iq: iterator query state.
1767  * @param id: module id.
1768  * @param name: target qname.
1769  * @param namelen: target qname length.
1770  * @param qtype: target qtype (either A or AAAA).
1771  * @param qclass: target qclass.
1772  * @return true on success, false on failure.
1773  */
1774 static int
1775 generate_target_query(struct module_qstate* qstate, struct iter_qstate* iq,
1776         int id, uint8_t* name, size_t namelen, uint16_t qtype, uint16_t qclass)
1777 {
1778         struct module_qstate* subq;
1779         if(!generate_sub_request(name, namelen, qtype, qclass, qstate,
1780                 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0))
1781                 return 0;
1782         log_nametypeclass(VERB_QUERY, "new target", name, qtype, qclass);
1783         return 1;
1784 }
1785
1786 /**
1787  * Given an event at a certain state, generate zero or more target queries
1788  * for it's current delegation point.
1789  *
1790  * @param qstate: query state.
1791  * @param iq: iterator query state.
1792  * @param ie: iterator shared global environment.
1793  * @param id: module id.
1794  * @param maxtargets: The maximum number of targets to query for.
1795  *      if it is negative, there is no maximum number of targets.
1796  * @param num: returns the number of queries generated and processed,
1797  *      which may be zero if there were no missing targets.
1798  * @return false on error.
1799  */
1800 static int
1801 query_for_targets(struct module_qstate* qstate, struct iter_qstate* iq,
1802         struct iter_env* ie, int id, int maxtargets, int* num)
1803 {
1804         int query_count = 0;
1805         struct delegpt_ns* ns;
1806         int missing;
1807         int toget = 0;
1808
1809         if(iq->depth == ie->max_dependency_depth)
1810                 return 0;
1811         if(iq->depth > 0 && iq->target_count &&
1812                 iq->target_count[1] > MAX_TARGET_COUNT) {
1813                 char s[LDNS_MAX_DOMAINLEN+1];
1814                 dname_str(qstate->qinfo.qname, s);
1815                 verbose(VERB_QUERY, "request %s has exceeded the maximum "
1816                         "number of glue fetches %d", s, iq->target_count[1]);
1817                 return 0;
1818         }
1819         if(iq->dp_target_count > MAX_DP_TARGET_COUNT) {
1820                 char s[LDNS_MAX_DOMAINLEN+1];
1821                 dname_str(qstate->qinfo.qname, s);
1822                 verbose(VERB_QUERY, "request %s has exceeded the maximum "
1823                         "number of glue fetches %d to a single delegation point",
1824                         s, iq->dp_target_count);
1825                 return 0;
1826         }
1827
1828         iter_mark_cycle_targets(qstate, iq->dp);
1829         missing = (int)delegpt_count_missing_targets(iq->dp);
1830         log_assert(maxtargets != 0); /* that would not be useful */
1831
1832         /* Generate target requests. Basically, any missing targets
1833          * are queried for here, regardless if it is necessary to do
1834          * so to continue processing. */
1835         if(maxtargets < 0 || maxtargets > missing)
1836                 toget = missing;
1837         else    toget = maxtargets;
1838         if(toget == 0) {
1839                 *num = 0;
1840                 return 1;
1841         }
1842         /* select 'toget' items from the total of 'missing' items */
1843         log_assert(toget <= missing);
1844
1845         /* loop over missing targets */
1846         for(ns = iq->dp->nslist; ns; ns = ns->next) {
1847                 if(ns->resolved)
1848                         continue;
1849
1850                 /* randomly select this item with probability toget/missing */
1851                 if(!iter_ns_probability(qstate->env->rnd, toget, missing)) {
1852                         /* do not select this one, next; select toget number
1853                          * of items from a list one less in size */
1854                         missing --;
1855                         continue;
1856                 }
1857
1858                 if(ie->supports_ipv6 && !ns->got6) {
1859                         /* Send the AAAA request. */
1860                         if(!generate_target_query(qstate, iq, id,
1861                                 ns->name, ns->namelen,
1862                                 LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) {
1863                                 *num = query_count;
1864                                 if(query_count > 0)
1865                                         qstate->ext_state[id] = module_wait_subquery;
1866                                 return 0;
1867                         }
1868                         query_count++;
1869                 }
1870                 /* Send the A request. */
1871                 if(ie->supports_ipv4 && !ns->got4) {
1872                         if(!generate_target_query(qstate, iq, id,
1873                                 ns->name, ns->namelen,
1874                                 LDNS_RR_TYPE_A, iq->qchase.qclass)) {
1875                                 *num = query_count;
1876                                 if(query_count > 0)
1877                                         qstate->ext_state[id] = module_wait_subquery;
1878                                 return 0;
1879                         }
1880                         query_count++;
1881                 }
1882
1883                 /* mark this target as in progress. */
1884                 ns->resolved = 1;
1885                 missing--;
1886                 toget--;
1887                 if(toget == 0)
1888                         break;
1889         }
1890         *num = query_count;
1891         if(query_count > 0)
1892                 qstate->ext_state[id] = module_wait_subquery;
1893
1894         return 1;
1895 }
1896
1897 /**
1898  * Called by processQueryTargets when it would like extra targets to query
1899  * but it seems to be out of options.  At last resort some less appealing
1900  * options are explored.  If there are no more options, the result is SERVFAIL
1901  *
1902  * @param qstate: query state.
1903  * @param iq: iterator query state.
1904  * @param ie: iterator shared global environment.
1905  * @param id: module id.
1906  * @return true if the event requires more request processing immediately,
1907  *         false if not.
1908  */
1909 static int
1910 processLastResort(struct module_qstate* qstate, struct iter_qstate* iq,
1911         struct iter_env* ie, int id)
1912 {
1913         struct delegpt_ns* ns;
1914         int query_count = 0;
1915         verbose(VERB_ALGO, "No more query targets, attempting last resort");
1916         log_assert(iq->dp);
1917
1918         if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen,
1919                 iq->qchase.qclass, NULL)) {
1920                 /* fail -- no more targets, no more hope of targets, no hope
1921                  * of a response. */
1922                 errinf(qstate, "all the configured stub or forward servers failed,");
1923                 errinf_dname(qstate, "at zone", iq->dp->name);
1924                 verbose(VERB_QUERY, "configured stub or forward servers failed -- returning SERVFAIL");
1925                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1926         }
1927         if(!iq->dp->has_parent_side_NS && dname_is_root(iq->dp->name)) {
1928                 struct delegpt* p = hints_lookup_root(qstate->env->hints,
1929                         iq->qchase.qclass);
1930                 if(p) {
1931                         struct delegpt_addr* a;
1932                         iq->chase_flags &= ~BIT_RD; /* go to authorities */
1933                         for(ns = p->nslist; ns; ns=ns->next) {
1934                                 (void)delegpt_add_ns(iq->dp, qstate->region,
1935                                         ns->name, ns->lame);
1936                         }
1937                         for(a = p->target_list; a; a=a->next_target) {
1938                                 (void)delegpt_add_addr(iq->dp, qstate->region,
1939                                         &a->addr, a->addrlen, a->bogus,
1940                                         a->lame, a->tls_auth_name, NULL);
1941                         }
1942                 }
1943                 iq->dp->has_parent_side_NS = 1;
1944         } else if(!iq->dp->has_parent_side_NS) {
1945                 if(!iter_lookup_parent_NS_from_cache(qstate->env, iq->dp,
1946                         qstate->region, &qstate->qinfo)
1947                         || !iq->dp->has_parent_side_NS) {
1948                         /* if: malloc failure in lookup go up to try */
1949                         /* if: no parent NS in cache - go up one level */
1950                         verbose(VERB_ALGO, "try to grab parent NS");
1951                         iq->store_parent_NS = iq->dp;
1952                         iq->chase_flags &= ~BIT_RD; /* go to authorities */
1953                         iq->deleg_msg = NULL;
1954                         iq->refetch_glue = 1;
1955                         iq->query_restart_count++;
1956                         iq->sent_count = 0;
1957                         iq->dp_target_count = 0;
1958                         if(qstate->env->cfg->qname_minimisation)
1959                                 iq->minimisation_state = INIT_MINIMISE_STATE;
1960                         return next_state(iq, INIT_REQUEST_STATE);
1961                 }
1962         }
1963         /* see if that makes new names available */
1964         if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
1965                 qstate->region, iq->dp))
1966                 log_err("out of memory in cache_fill_missing");
1967         if(iq->dp->usable_list) {
1968                 verbose(VERB_ALGO, "try parent-side-name, w. glue from cache");
1969                 return next_state(iq, QUERYTARGETS_STATE);
1970         }
1971         /* try to fill out parent glue from cache */
1972         if(iter_lookup_parent_glue_from_cache(qstate->env, iq->dp,
1973                 qstate->region, &qstate->qinfo)) {
1974                 /* got parent stuff from cache, see if we can continue */
1975                 verbose(VERB_ALGO, "try parent-side glue from cache");
1976                 return next_state(iq, QUERYTARGETS_STATE);
1977         }
1978         /* query for an extra name added by the parent-NS record */
1979         if(delegpt_count_missing_targets(iq->dp) > 0) {
1980                 int qs = 0;
1981                 verbose(VERB_ALGO, "try parent-side target name");
1982                 if(!query_for_targets(qstate, iq, ie, id, 1, &qs)) {
1983                         errinf(qstate, "could not fetch nameserver");
1984                         errinf_dname(qstate, "at zone", iq->dp->name);
1985                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1986                 }
1987                 iq->num_target_queries += qs;
1988                 target_count_increase(iq, qs);
1989                 if(qs != 0) {
1990                         qstate->ext_state[id] = module_wait_subquery;
1991                         return 0; /* and wait for them */
1992                 }
1993         }
1994         if(iq->depth == ie->max_dependency_depth) {
1995                 verbose(VERB_QUERY, "maxdepth and need more nameservers, fail");
1996                 errinf(qstate, "cannot fetch more nameservers because at max dependency depth");
1997                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1998         }
1999         if(iq->depth > 0 && iq->target_count &&
2000                 iq->target_count[1] > MAX_TARGET_COUNT) {
2001                 char s[LDNS_MAX_DOMAINLEN+1];
2002                 dname_str(qstate->qinfo.qname, s);
2003                 verbose(VERB_QUERY, "request %s has exceeded the maximum "
2004                         "number of glue fetches %d", s, iq->target_count[1]);
2005                 errinf(qstate, "exceeded the maximum number of glue fetches");
2006                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
2007         }
2008         /* mark cycle targets for parent-side lookups */
2009         iter_mark_pside_cycle_targets(qstate, iq->dp);
2010         /* see if we can issue queries to get nameserver addresses */
2011         /* this lookup is not randomized, but sequential. */
2012         for(ns = iq->dp->nslist; ns; ns = ns->next) {
2013                 /* if this nameserver is at a delegation point, but that
2014                  * delegation point is a stub and we cannot go higher, skip*/
2015                 if( ((ie->supports_ipv6 && !ns->done_pside6) ||
2016                     (ie->supports_ipv4 && !ns->done_pside4)) &&
2017                     !can_have_last_resort(qstate->env, ns->name, ns->namelen,
2018                         iq->qchase.qclass, NULL)) {
2019                         log_nametypeclass(VERB_ALGO, "cannot pside lookup ns "
2020                                 "because it is also a stub/forward,",
2021                                 ns->name, LDNS_RR_TYPE_NS, iq->qchase.qclass);
2022                         if(ie->supports_ipv6) ns->done_pside6 = 1;
2023                         if(ie->supports_ipv4) ns->done_pside4 = 1;
2024                         continue;
2025                 }
2026                 /* query for parent-side A and AAAA for nameservers */
2027                 if(ie->supports_ipv6 && !ns->done_pside6) {
2028                         /* Send the AAAA request. */
2029                         if(!generate_parentside_target_query(qstate, iq, id,
2030                                 ns->name, ns->namelen,
2031                                 LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) {
2032                                 errinf_dname(qstate, "could not generate nameserver AAAA lookup for", ns->name);
2033                                 return error_response(qstate, id,
2034                                         LDNS_RCODE_SERVFAIL);
2035                         }
2036                         ns->done_pside6 = 1;
2037                         query_count++;
2038                 }
2039                 if(ie->supports_ipv4 && !ns->done_pside4) {
2040                         /* Send the A request. */
2041                         if(!generate_parentside_target_query(qstate, iq, id,
2042                                 ns->name, ns->namelen,
2043                                 LDNS_RR_TYPE_A, iq->qchase.qclass)) {
2044                                 errinf_dname(qstate, "could not generate nameserver A lookup for", ns->name);
2045                                 return error_response(qstate, id,
2046                                         LDNS_RCODE_SERVFAIL);
2047                         }
2048                         ns->done_pside4 = 1;
2049                         query_count++;
2050                 }
2051                 if(query_count != 0) { /* suspend to await results */
2052                         verbose(VERB_ALGO, "try parent-side glue lookup");
2053                         iq->num_target_queries += query_count;
2054                         target_count_increase(iq, query_count);
2055                         qstate->ext_state[id] = module_wait_subquery;
2056                         return 0;
2057                 }
2058         }
2059
2060         /* if this was a parent-side glue query itself, then store that
2061          * failure in cache. */
2062         if(!qstate->no_cache_store && iq->query_for_pside_glue
2063                 && !iq->pside_glue)
2064                         iter_store_parentside_neg(qstate->env, &qstate->qinfo,
2065                                 iq->deleg_msg?iq->deleg_msg->rep:
2066                                 (iq->response?iq->response->rep:NULL));
2067
2068         errinf(qstate, "all servers for this domain failed,");
2069         errinf_dname(qstate, "at zone", iq->dp->name);
2070         verbose(VERB_QUERY, "out of query targets -- returning SERVFAIL");
2071         /* fail -- no more targets, no more hope of targets, no hope
2072          * of a response. */
2073         return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
2074 }
2075
2076 /**
2077  * Try to find the NS record set that will resolve a qtype DS query. Due
2078  * to grandparent/grandchild reasons we did not get a proper lookup right
2079  * away.  We need to create type NS queries until we get the right parent
2080  * for this lookup.  We remove labels from the query to find the right point.
2081  * If we end up at the old dp name, then there is no solution.
2082  *
2083  * @param qstate: query state.
2084  * @param iq: iterator query state.
2085  * @param id: module id.
2086  * @return true if the event requires more immediate processing, false if
2087  *         not. This is generally only true when forwarding the request to
2088  *         the final state (i.e., on answer).
2089  */
2090 static int
2091 processDSNSFind(struct module_qstate* qstate, struct iter_qstate* iq, int id)
2092 {
2093         struct module_qstate* subq = NULL;
2094         verbose(VERB_ALGO, "processDSNSFind");
2095
2096         if(!iq->dsns_point) {
2097                 /* initialize */
2098                 iq->dsns_point = iq->qchase.qname;
2099                 iq->dsns_point_len = iq->qchase.qname_len;
2100         }
2101         /* robustcheck for internal error: we are not underneath the dp */
2102         if(!dname_subdomain_c(iq->dsns_point, iq->dp->name)) {
2103                 errinf_dname(qstate, "for DS query parent-child nameserver search the query is not under the zone", iq->dp->name);
2104                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
2105         }
2106
2107         /* go up one (more) step, until we hit the dp, if so, end */
2108         dname_remove_label(&iq->dsns_point, &iq->dsns_point_len);
2109         if(query_dname_compare(iq->dsns_point, iq->dp->name) == 0) {
2110                 /* there was no inbetween nameserver, use the old delegation
2111                  * point again.  And this time, because dsns_point is nonNULL
2112                  * we are going to accept the (bad) result */
2113                 iq->state = QUERYTARGETS_STATE;
2114                 return 1;
2115         }
2116         iq->state = DSNS_FIND_STATE;
2117
2118         /* spawn NS lookup (validation not needed, this is for DS lookup) */
2119         log_nametypeclass(VERB_ALGO, "fetch nameservers",
2120                 iq->dsns_point, LDNS_RR_TYPE_NS, iq->qchase.qclass);
2121         if(!generate_sub_request(iq->dsns_point, iq->dsns_point_len,
2122                 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
2123                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0)) {
2124                 errinf_dname(qstate, "for DS query parent-child nameserver search, could not generate NS lookup for", iq->dsns_point);
2125                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
2126         }
2127
2128         return 0;
2129 }
2130
2131 /**
2132  * This is the request event state where the request will be sent to one of
2133  * its current query targets. This state also handles issuing target lookup
2134  * queries for missing target IP addresses. Queries typically iterate on
2135  * this state, both when they are just trying different targets for a given
2136  * delegation point, and when they change delegation points. This state
2137  * roughly corresponds to RFC 1034 algorithm steps 3 and 4.
2138  *
2139  * @param qstate: query state.
2140  * @param iq: iterator query state.
2141  * @param ie: iterator shared global environment.
2142  * @param id: module id.
2143  * @return true if the event requires more request processing immediately,
2144  *         false if not. This state only returns true when it is generating
2145  *         a SERVFAIL response because the query has hit a dead end.
2146  */
2147 static int
2148 processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
2149         struct iter_env* ie, int id)
2150 {
2151         int tf_policy;
2152         struct delegpt_addr* target;
2153         struct outbound_entry* outq;
2154         int auth_fallback = 0;
2155         uint8_t* qout_orig = NULL;
2156         size_t qout_orig_len = 0;
2157
2158         /* NOTE: a request will encounter this state for each target it
2159          * needs to send a query to. That is, at least one per referral,
2160          * more if some targets timeout or return throwaway answers. */
2161
2162         log_query_info(VERB_QUERY, "processQueryTargets:", &qstate->qinfo);
2163         verbose(VERB_ALGO, "processQueryTargets: targetqueries %d, "
2164                 "currentqueries %d sentcount %d", iq->num_target_queries,
2165                 iq->num_current_queries, iq->sent_count);
2166
2167         /* Make sure that we haven't run away */
2168         /* FIXME: is this check even necessary? */
2169         if(iq->referral_count > MAX_REFERRAL_COUNT) {
2170                 verbose(VERB_QUERY, "request has exceeded the maximum "
2171                         "number of referrrals with %d", iq->referral_count);
2172                 errinf(qstate, "exceeded the maximum of referrals");
2173                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2174         }
2175         if(iq->sent_count > MAX_SENT_COUNT) {
2176                 verbose(VERB_QUERY, "request has exceeded the maximum "
2177                         "number of sends with %d", iq->sent_count);
2178                 errinf(qstate, "exceeded the maximum number of sends");
2179                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2180         }
2181         if(iq->target_count && iq->target_count[2] > MAX_TARGET_NX) {
2182                 verbose(VERB_QUERY, "request has exceeded the maximum "
2183                         " number of nxdomain nameserver lookups with %d",
2184                         iq->target_count[2]);
2185                 errinf(qstate, "exceeded the maximum nameserver nxdomains");
2186                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2187         }
2188
2189         /* Make sure we have a delegation point, otherwise priming failed
2190          * or another failure occurred */
2191         if(!iq->dp) {
2192                 verbose(VERB_QUERY, "Failed to get a delegation, giving up");
2193                 errinf(qstate, "failed to get a delegation (eg. prime failure)");
2194                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2195         }
2196         if(!ie->supports_ipv6)
2197                 delegpt_no_ipv6(iq->dp);
2198         if(!ie->supports_ipv4)
2199                 delegpt_no_ipv4(iq->dp);
2200         delegpt_log(VERB_ALGO, iq->dp);
2201
2202         if(iq->num_current_queries>0) {
2203                 /* already busy answering a query, this restart is because
2204                  * more delegpt addrs became available, wait for existing
2205                  * query. */
2206                 verbose(VERB_ALGO, "woke up, but wait for outstanding query");
2207                 qstate->ext_state[id] = module_wait_reply;
2208                 return 0;
2209         }
2210
2211         if(iq->minimisation_state == INIT_MINIMISE_STATE
2212                 && !(iq->chase_flags & BIT_RD)) {
2213                 /* (Re)set qinfo_out to (new) delegation point, except when
2214                  * qinfo_out is already a subdomain of dp. This happens when
2215                  * increasing by more than one label at once (QNAMEs with more
2216                  * than MAX_MINIMISE_COUNT labels). */
2217                 if(!(iq->qinfo_out.qname_len
2218                         && dname_subdomain_c(iq->qchase.qname,
2219                                 iq->qinfo_out.qname)
2220                         && dname_subdomain_c(iq->qinfo_out.qname,
2221                                 iq->dp->name))) {
2222                         iq->qinfo_out.qname = iq->dp->name;
2223                         iq->qinfo_out.qname_len = iq->dp->namelen;
2224                         iq->qinfo_out.qtype = LDNS_RR_TYPE_A;
2225                         iq->qinfo_out.qclass = iq->qchase.qclass;
2226                         iq->qinfo_out.local_alias = NULL;
2227                         iq->minimise_count = 0;
2228                 }
2229
2230                 iq->minimisation_state = MINIMISE_STATE;
2231         }
2232         if(iq->minimisation_state == MINIMISE_STATE) {
2233                 int qchaselabs = dname_count_labels(iq->qchase.qname);
2234                 int labdiff = qchaselabs -
2235                         dname_count_labels(iq->qinfo_out.qname);
2236
2237                 qout_orig = iq->qinfo_out.qname;
2238                 qout_orig_len = iq->qinfo_out.qname_len;
2239                 iq->qinfo_out.qname = iq->qchase.qname;
2240                 iq->qinfo_out.qname_len = iq->qchase.qname_len;
2241                 iq->minimise_count++;
2242                 iq->minimise_timeout_count = 0;
2243
2244                 iter_dec_attempts(iq->dp, 1);
2245
2246                 /* Limit number of iterations for QNAMEs with more
2247                  * than MAX_MINIMISE_COUNT labels. Send first MINIMISE_ONE_LAB
2248                  * labels of QNAME always individually.
2249                  */
2250                 if(qchaselabs > MAX_MINIMISE_COUNT && labdiff > 1 &&
2251                         iq->minimise_count > MINIMISE_ONE_LAB) {
2252                         if(iq->minimise_count < MAX_MINIMISE_COUNT) {
2253                                 int multilabs = qchaselabs - 1 -
2254                                         MINIMISE_ONE_LAB;
2255                                 int extralabs = multilabs /
2256                                         MINIMISE_MULTIPLE_LABS;
2257
2258                                 if (MAX_MINIMISE_COUNT - iq->minimise_count >=
2259                                         multilabs % MINIMISE_MULTIPLE_LABS)
2260                                         /* Default behaviour is to add 1 label
2261                                          * every iteration. Therefore, decrement
2262                                          * the extralabs by 1 */
2263                                         extralabs--;
2264                                 if (extralabs < labdiff)
2265                                         labdiff -= extralabs;
2266                                 else
2267                                         labdiff = 1;
2268                         }
2269                         /* Last minimised iteration, send all labels with
2270                          * QTYPE=NS */
2271                         else
2272                                 labdiff = 1;
2273                 }
2274
2275                 if(labdiff > 1) {
2276                         verbose(VERB_QUERY, "removing %d labels", labdiff-1);
2277                         dname_remove_labels(&iq->qinfo_out.qname,
2278                                 &iq->qinfo_out.qname_len,
2279                                 labdiff-1);
2280                 }
2281                 if(labdiff < 1 || (labdiff < 2
2282                         && (iq->qchase.qtype == LDNS_RR_TYPE_DS
2283                         || iq->qchase.qtype == LDNS_RR_TYPE_A)))
2284                         /* Stop minimising this query, resolve "as usual" */
2285                         iq->minimisation_state = DONOT_MINIMISE_STATE;
2286                 else if(!qstate->no_cache_lookup) {
2287                         struct dns_msg* msg = dns_cache_lookup(qstate->env,
2288                                 iq->qinfo_out.qname, iq->qinfo_out.qname_len,
2289                                 iq->qinfo_out.qtype, iq->qinfo_out.qclass,
2290                                 qstate->query_flags, qstate->region,
2291                                 qstate->env->scratch, 0);
2292                         if(msg && FLAGS_GET_RCODE(msg->rep->flags) ==
2293                                 LDNS_RCODE_NOERROR)
2294                                 /* no need to send query if it is already
2295                                  * cached as NOERROR */
2296                                 return 1;
2297                         if(msg && FLAGS_GET_RCODE(msg->rep->flags) ==
2298                                 LDNS_RCODE_NXDOMAIN &&
2299                                 qstate->env->need_to_validate &&
2300                                 qstate->env->cfg->harden_below_nxdomain) {
2301                                 if(msg->rep->security == sec_status_secure) {
2302                                         iq->response = msg;
2303                                         return final_state(iq);
2304                                 }
2305                                 if(msg->rep->security == sec_status_unchecked) {
2306                                         struct module_qstate* subq = NULL;
2307                                         if(!generate_sub_request(
2308                                                 iq->qinfo_out.qname,
2309                                                 iq->qinfo_out.qname_len,
2310                                                 iq->qinfo_out.qtype,
2311                                                 iq->qinfo_out.qclass,
2312                                                 qstate, id, iq,
2313                                                 INIT_REQUEST_STATE,
2314                                                 FINISHED_STATE, &subq, 1, 1))
2315                                                 verbose(VERB_ALGO,
2316                                                 "could not validate NXDOMAIN "
2317                                                 "response");
2318                                 }
2319                         }
2320                         if(msg && FLAGS_GET_RCODE(msg->rep->flags) ==
2321                                 LDNS_RCODE_NXDOMAIN) {
2322                                 /* return and add a label in the next
2323                                  * minimisation iteration.
2324                                  */
2325                                 return 1;
2326                         }
2327                 }
2328         }
2329         if(iq->minimisation_state == SKIP_MINIMISE_STATE) {
2330                 if(iq->minimise_timeout_count < MAX_MINIMISE_TIMEOUT_COUNT)
2331                         /* Do not increment qname, continue incrementing next
2332                          * iteration */
2333                         iq->minimisation_state = MINIMISE_STATE;
2334                 else if(!qstate->env->cfg->qname_minimisation_strict)
2335                         /* Too many time-outs detected for this QNAME and QTYPE.
2336                          * We give up, disable QNAME minimisation. */
2337                         iq->minimisation_state = DONOT_MINIMISE_STATE;
2338         }
2339         if(iq->minimisation_state == DONOT_MINIMISE_STATE)
2340                 iq->qinfo_out = iq->qchase;
2341
2342         /* now find an answer to this query */
2343         /* see if authority zones have an answer */
2344         /* now we know the dp, we can check the auth zone for locally hosted
2345          * contents */
2346         if(!iq->auth_zone_avoid && qstate->blacklist) {
2347                 if(auth_zones_can_fallback(qstate->env->auth_zones,
2348                         iq->dp->name, iq->dp->namelen, iq->qinfo_out.qclass)) {
2349                         /* if cache is blacklisted and this zone allows us
2350                          * to fallback to the internet, then do so, and
2351                          * fetch results from the internet servers */
2352                         iq->auth_zone_avoid = 1;
2353                 }
2354         }
2355         if(iq->auth_zone_avoid) {
2356                 iq->auth_zone_avoid = 0;
2357                 auth_fallback = 1;
2358         } else if(auth_zones_lookup(qstate->env->auth_zones, &iq->qinfo_out,
2359                 qstate->region, &iq->response, &auth_fallback, iq->dp->name,
2360                 iq->dp->namelen)) {
2361                 /* use this as a response to be processed by the iterator */
2362                 if(verbosity >= VERB_ALGO) {
2363                         log_dns_msg("msg from auth zone",
2364                                 &iq->response->qinfo, iq->response->rep);
2365                 }
2366                 if((iq->chase_flags&BIT_RD) && !(iq->response->rep->flags&BIT_AA)) {
2367                         verbose(VERB_ALGO, "forwarder, ignoring referral from auth zone");
2368                 } else {
2369                         lock_rw_wrlock(&qstate->env->auth_zones->lock);
2370                         qstate->env->auth_zones->num_query_up++;
2371                         lock_rw_unlock(&qstate->env->auth_zones->lock);
2372                         iq->num_current_queries++;
2373                         iq->chase_to_rd = 0;
2374                         iq->dnssec_lame_query = 0;
2375                         iq->auth_zone_response = 1;
2376                         return next_state(iq, QUERY_RESP_STATE);
2377                 }
2378         }
2379         iq->auth_zone_response = 0;
2380         if(auth_fallback == 0) {
2381                 /* like we got servfail from the auth zone lookup, and
2382                  * no internet fallback */
2383                 verbose(VERB_ALGO, "auth zone lookup failed, no fallback,"
2384                         " servfail");
2385                 errinf(qstate, "auth zone lookup failed, fallback is off");
2386                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2387         }
2388         if(iq->dp->auth_dp) {
2389                 /* we wanted to fallback, but had no delegpt, only the
2390                  * auth zone generated delegpt, create an actual one */
2391                 iq->auth_zone_avoid = 1;
2392                 return next_state(iq, INIT_REQUEST_STATE);
2393         }
2394         /* but mostly, fallback==1 (like, when no such auth zone exists)
2395          * and we continue with lookups */
2396
2397         tf_policy = 0;
2398         /* < not <=, because although the array is large enough for <=, the
2399          * generated query will immediately be discarded due to depth and
2400          * that servfail is cached, which is not good as opportunism goes. */
2401         if(iq->depth < ie->max_dependency_depth
2402                 && iq->num_target_queries == 0
2403                 && (!iq->target_count || iq->target_count[2]==0)
2404                 && iq->sent_count < TARGET_FETCH_STOP) {
2405                 tf_policy = ie->target_fetch_policy[iq->depth];
2406         }
2407
2408         /* if in 0x20 fallback get as many targets as possible */
2409         if(iq->caps_fallback) {
2410                 int extra = 0;
2411                 size_t naddr, nres, navail;
2412                 if(!query_for_targets(qstate, iq, ie, id, -1, &extra)) {
2413                         errinf(qstate, "could not fetch nameservers for 0x20 fallback");
2414                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2415                 }
2416                 iq->num_target_queries += extra;
2417                 target_count_increase(iq, extra);
2418                 if(iq->num_target_queries > 0) {
2419                         /* wait to get all targets, we want to try em */
2420                         verbose(VERB_ALGO, "wait for all targets for fallback");
2421                         qstate->ext_state[id] = module_wait_reply;
2422                         /* undo qname minimise step because we'll get back here
2423                          * to do it again */
2424                         if(qout_orig && iq->minimise_count > 0) {
2425                                 iq->minimise_count--;
2426                                 iq->qinfo_out.qname = qout_orig;
2427                                 iq->qinfo_out.qname_len = qout_orig_len;
2428                         }
2429                         return 0;
2430                 }
2431                 /* did we do enough fallback queries already? */
2432                 delegpt_count_addr(iq->dp, &naddr, &nres, &navail);
2433                 /* the current caps_server is the number of fallbacks sent.
2434                  * the original query is one that matched too, so we have
2435                  * caps_server+1 number of matching queries now */
2436                 if(iq->caps_server+1 >= naddr*3 ||
2437                         iq->caps_server*2+2 >= MAX_SENT_COUNT) {
2438                         /* *2 on sentcount check because ipv6 may fail */
2439                         /* we're done, process the response */
2440                         verbose(VERB_ALGO, "0x20 fallback had %d responses "
2441                                 "match for %d wanted, done.",
2442                                 (int)iq->caps_server+1, (int)naddr*3);
2443                         iq->response = iq->caps_response;
2444                         iq->caps_fallback = 0;
2445                         iter_dec_attempts(iq->dp, 3); /* space for fallback */
2446                         iq->num_current_queries++; /* RespState decrements it*/
2447                         iq->referral_count++; /* make sure we don't loop */
2448                         iq->sent_count = 0;
2449                         iq->dp_target_count = 0;
2450                         iq->state = QUERY_RESP_STATE;
2451                         return 1;
2452                 }
2453                 verbose(VERB_ALGO, "0x20 fallback number %d",
2454                         (int)iq->caps_server);
2455
2456         /* if there is a policy to fetch missing targets
2457          * opportunistically, do it. we rely on the fact that once a
2458          * query (or queries) for a missing name have been issued,
2459          * they will not show up again. */
2460         } else if(tf_policy != 0) {
2461                 int extra = 0;
2462                 verbose(VERB_ALGO, "attempt to get extra %d targets",
2463                         tf_policy);
2464                 (void)query_for_targets(qstate, iq, ie, id, tf_policy, &extra);
2465                 /* errors ignored, these targets are not strictly necessary for
2466                  * this result, we do not have to reply with SERVFAIL */
2467                 iq->num_target_queries += extra;
2468                 target_count_increase(iq, extra);
2469         }
2470
2471         /* Add the current set of unused targets to our queue. */
2472         delegpt_add_unused_targets(iq->dp);
2473
2474         /* Select the next usable target, filtering out unsuitable targets. */
2475         target = iter_server_selection(ie, qstate->env, iq->dp,
2476                 iq->dp->name, iq->dp->namelen, iq->qchase.qtype,
2477                 &iq->dnssec_lame_query, &iq->chase_to_rd,
2478                 iq->num_target_queries, qstate->blacklist,
2479                 qstate->prefetch_leeway);
2480
2481         /* If no usable target was selected... */
2482         if(!target) {
2483                 /* Here we distinguish between three states: generate a new
2484                  * target query, just wait, or quit (with a SERVFAIL).
2485                  * We have the following information: number of active
2486                  * target queries, number of active current queries,
2487                  * the presence of missing targets at this delegation
2488                  * point, and the given query target policy. */
2489
2490                 /* Check for the wait condition. If this is true, then
2491                  * an action must be taken. */
2492                 if(iq->num_target_queries==0 && iq->num_current_queries==0) {
2493                         /* If there is nothing to wait for, then we need
2494                          * to distinguish between generating (a) new target
2495                          * query, or failing. */
2496                         if(delegpt_count_missing_targets(iq->dp) > 0) {
2497                                 int qs = 0;
2498                                 verbose(VERB_ALGO, "querying for next "
2499                                         "missing target");
2500                                 if(!query_for_targets(qstate, iq, ie, id,
2501                                         1, &qs)) {
2502                                         errinf(qstate, "could not fetch nameserver");
2503                                         errinf_dname(qstate, "at zone", iq->dp->name);
2504                                         return error_response(qstate, id,
2505                                                 LDNS_RCODE_SERVFAIL);
2506                                 }
2507                                 if(qs == 0 &&
2508                                    delegpt_count_missing_targets(iq->dp) == 0){
2509                                         /* it looked like there were missing
2510                                          * targets, but they did not turn up.
2511                                          * Try the bad choices again (if any),
2512                                          * when we get back here missing==0,
2513                                          * so this is not a loop. */
2514                                         return 1;
2515                                 }
2516                                 iq->num_target_queries += qs;
2517                                 target_count_increase(iq, qs);
2518                         }
2519                         /* Since a target query might have been made, we
2520                          * need to check again. */
2521                         if(iq->num_target_queries == 0) {
2522                                 /* if in capsforid fallback, instead of last
2523                                  * resort, we agree with the current reply
2524                                  * we have (if any) (our count of addrs bad)*/
2525                                 if(iq->caps_fallback && iq->caps_reply) {
2526                                         /* we're done, process the response */
2527                                         verbose(VERB_ALGO, "0x20 fallback had %d responses, "
2528                                                 "but no more servers except "
2529                                                 "last resort, done.",
2530                                                 (int)iq->caps_server+1);
2531                                         iq->response = iq->caps_response;
2532                                         iq->caps_fallback = 0;
2533                                         iter_dec_attempts(iq->dp, 3); /* space for fallback */
2534                                         iq->num_current_queries++; /* RespState decrements it*/
2535                                         iq->referral_count++; /* make sure we don't loop */
2536                                         iq->sent_count = 0;
2537                                         iq->dp_target_count = 0;
2538                                         iq->state = QUERY_RESP_STATE;
2539                                         return 1;
2540                                 }
2541                                 return processLastResort(qstate, iq, ie, id);
2542                         }
2543                 }
2544
2545                 /* otherwise, we have no current targets, so submerge
2546                  * until one of the target or direct queries return. */
2547                 if(iq->num_target_queries>0 && iq->num_current_queries>0) {
2548                         verbose(VERB_ALGO, "no current targets -- waiting "
2549                                 "for %d targets to resolve or %d outstanding"
2550                                 " queries to respond", iq->num_target_queries,
2551                                 iq->num_current_queries);
2552                         qstate->ext_state[id] = module_wait_reply;
2553                 } else if(iq->num_target_queries>0) {
2554                         verbose(VERB_ALGO, "no current targets -- waiting "
2555                                 "for %d targets to resolve.",
2556                                 iq->num_target_queries);
2557                         qstate->ext_state[id] = module_wait_subquery;
2558                 } else {
2559                         verbose(VERB_ALGO, "no current targets -- waiting "
2560                                 "for %d outstanding queries to respond.",
2561                                 iq->num_current_queries);
2562                         qstate->ext_state[id] = module_wait_reply;
2563                 }
2564                 /* undo qname minimise step because we'll get back here
2565                  * to do it again */
2566                 if(qout_orig && iq->minimise_count > 0) {
2567                         iq->minimise_count--;
2568                         iq->qinfo_out.qname = qout_orig;
2569                         iq->qinfo_out.qname_len = qout_orig_len;
2570                 }
2571                 return 0;
2572         }
2573
2574         /* if not forwarding, check ratelimits per delegationpoint name */
2575         if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok) {
2576                 if(!infra_ratelimit_inc(qstate->env->infra_cache, iq->dp->name,
2577                         iq->dp->namelen, *qstate->env->now, &qstate->qinfo,
2578                         qstate->reply)) {
2579                         lock_basic_lock(&ie->queries_ratelimit_lock);
2580                         ie->num_queries_ratelimited++;
2581                         lock_basic_unlock(&ie->queries_ratelimit_lock);
2582                         verbose(VERB_ALGO, "query exceeded ratelimits");
2583                         qstate->was_ratelimited = 1;
2584                         errinf_dname(qstate, "exceeded ratelimit for zone",
2585                                 iq->dp->name);
2586                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2587                 }
2588         }
2589
2590         /* We have a valid target. */
2591         if(verbosity >= VERB_QUERY) {
2592                 log_query_info(VERB_QUERY, "sending query:", &iq->qinfo_out);
2593                 log_name_addr(VERB_QUERY, "sending to target:", iq->dp->name,
2594                         &target->addr, target->addrlen);
2595                 verbose(VERB_ALGO, "dnssec status: %s%s",
2596                         iq->dnssec_expected?"expected": "not expected",
2597                         iq->dnssec_lame_query?" but lame_query anyway": "");
2598         }
2599         fptr_ok(fptr_whitelist_modenv_send_query(qstate->env->send_query));
2600         outq = (*qstate->env->send_query)(&iq->qinfo_out,
2601                 iq->chase_flags | (iq->chase_to_rd?BIT_RD:0),
2602                 /* unset CD if to forwarder(RD set) and not dnssec retry
2603                  * (blacklist nonempty) and no trust-anchors are configured
2604                  * above the qname or on the first attempt when dnssec is on */
2605                 EDNS_DO| ((iq->chase_to_rd||(iq->chase_flags&BIT_RD)!=0)&&
2606                 !qstate->blacklist&&(!iter_qname_indicates_dnssec(qstate->env,
2607                 &iq->qinfo_out)||target->attempts==1)?0:BIT_CD),
2608                 iq->dnssec_expected, iq->caps_fallback || is_caps_whitelisted(
2609                 ie, iq), &target->addr, target->addrlen,
2610                 iq->dp->name, iq->dp->namelen,
2611                 (iq->dp->ssl_upstream || qstate->env->cfg->ssl_upstream),
2612                 target->tls_auth_name, qstate);
2613         if(!outq) {
2614                 log_addr(VERB_DETAIL, "error sending query to auth server",
2615                         &target->addr, target->addrlen);
2616                 if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok)
2617                     infra_ratelimit_dec(qstate->env->infra_cache, iq->dp->name,
2618                         iq->dp->namelen, *qstate->env->now);
2619                 if(qstate->env->cfg->qname_minimisation)
2620                         iq->minimisation_state = SKIP_MINIMISE_STATE;
2621                 return next_state(iq, QUERYTARGETS_STATE);
2622         }
2623         outbound_list_insert(&iq->outlist, outq);
2624         iq->num_current_queries++;
2625         iq->sent_count++;
2626         qstate->ext_state[id] = module_wait_reply;
2627
2628         return 0;
2629 }
2630
2631 /** find NS rrset in given list */
2632 static struct ub_packed_rrset_key*
2633 find_NS(struct reply_info* rep, size_t from, size_t to)
2634 {
2635         size_t i;
2636         for(i=from; i<to; i++) {
2637                 if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NS)
2638                         return rep->rrsets[i];
2639         }
2640         return NULL;
2641 }
2642
2643
2644 /**
2645  * Process the query response. All queries end up at this state first. This
2646  * process generally consists of analyzing the response and routing the
2647  * event to the next state (either bouncing it back to a request state, or
2648  * terminating the processing for this event).
2649  *
2650  * @param qstate: query state.
2651  * @param iq: iterator query state.
2652  * @param id: module id.
2653  * @return true if the event requires more immediate processing, false if
2654  *         not. This is generally only true when forwarding the request to
2655  *         the final state (i.e., on answer).
2656  */
2657 static int
2658 processQueryResponse(struct module_qstate* qstate, struct iter_qstate* iq,
2659         int id)
2660 {
2661         int dnsseclame = 0;
2662         enum response_type type;
2663         iq->num_current_queries--;
2664
2665         if(!inplace_cb_query_response_call(qstate->env, qstate, iq->response))
2666                 log_err("unable to call query_response callback");
2667
2668         if(iq->response == NULL) {
2669                 /* Don't increment qname when QNAME minimisation is enabled */
2670                 if(qstate->env->cfg->qname_minimisation) {
2671                         iq->minimise_timeout_count++;
2672                         iq->minimisation_state = SKIP_MINIMISE_STATE;
2673                 }
2674                 iq->chase_to_rd = 0;
2675                 iq->dnssec_lame_query = 0;
2676                 verbose(VERB_ALGO, "query response was timeout");
2677                 return next_state(iq, QUERYTARGETS_STATE);
2678         }
2679         type = response_type_from_server(
2680                 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd),
2681                 iq->response, &iq->qinfo_out, iq->dp);
2682         iq->chase_to_rd = 0;
2683         if(type == RESPONSE_TYPE_REFERRAL && (iq->chase_flags&BIT_RD) &&
2684                 !iq->auth_zone_response) {
2685                 /* When forwarding (RD bit is set), we handle referrals
2686                  * differently. No queries should be sent elsewhere */
2687                 type = RESPONSE_TYPE_ANSWER;
2688         }
2689         if(!qstate->env->cfg->disable_dnssec_lame_check && iq->dnssec_expected
2690                 && !iq->dnssec_lame_query &&
2691                 !(iq->chase_flags&BIT_RD)
2692                 && iq->sent_count < DNSSEC_LAME_DETECT_COUNT
2693                 && type != RESPONSE_TYPE_LAME
2694                 && type != RESPONSE_TYPE_REC_LAME
2695                 && type != RESPONSE_TYPE_THROWAWAY
2696                 && type != RESPONSE_TYPE_UNTYPED) {
2697                 /* a possible answer, see if it is missing DNSSEC */
2698                 /* but not when forwarding, so we dont mark fwder lame */
2699                 if(!iter_msg_has_dnssec(iq->response)) {
2700                         /* Mark this address as dnsseclame in this dp,
2701                          * because that will make serverselection disprefer
2702                          * it, but also, once it is the only final option,
2703                          * use dnssec-lame-bypass if it needs to query there.*/
2704                         if(qstate->reply) {
2705                                 struct delegpt_addr* a = delegpt_find_addr(
2706                                         iq->dp, &qstate->reply->addr,
2707                                         qstate->reply->addrlen);
2708                                 if(a) a->dnsseclame = 1;
2709                         }
2710                         /* test the answer is from the zone we expected,
2711                          * otherwise, (due to parent,child on same server), we
2712                          * might mark the server,zone lame inappropriately */
2713                         if(!iter_msg_from_zone(iq->response, iq->dp, type,
2714                                 iq->qchase.qclass))
2715                                 qstate->reply = NULL;
2716                         type = RESPONSE_TYPE_LAME;
2717                         dnsseclame = 1;
2718                 }
2719         } else iq->dnssec_lame_query = 0;
2720         /* see if referral brings us close to the target */
2721         if(type == RESPONSE_TYPE_REFERRAL) {
2722                 struct ub_packed_rrset_key* ns = find_NS(
2723                         iq->response->rep, iq->response->rep->an_numrrsets,
2724                         iq->response->rep->an_numrrsets
2725                         + iq->response->rep->ns_numrrsets);
2726                 if(!ns) ns = find_NS(iq->response->rep, 0,
2727                                 iq->response->rep->an_numrrsets);
2728                 if(!ns || !dname_strict_subdomain_c(ns->rk.dname, iq->dp->name)
2729                         || !dname_subdomain_c(iq->qchase.qname, ns->rk.dname)){
2730                         verbose(VERB_ALGO, "bad referral, throwaway");
2731                         type = RESPONSE_TYPE_THROWAWAY;
2732                 } else
2733                         iter_scrub_ds(iq->response, ns, iq->dp->name);
2734         } else iter_scrub_ds(iq->response, NULL, NULL);
2735         if(type == RESPONSE_TYPE_THROWAWAY &&
2736                 FLAGS_GET_RCODE(iq->response->rep->flags) == LDNS_RCODE_YXDOMAIN) {
2737                 /* YXDOMAIN is a permanent error, no need to retry */
2738                 type = RESPONSE_TYPE_ANSWER;
2739         }
2740         if(type == RESPONSE_TYPE_CNAME && iq->response->rep->an_numrrsets >= 1
2741                 && ntohs(iq->response->rep->rrsets[0]->rk.type) == LDNS_RR_TYPE_DNAME) {
2742                 uint8_t* sname = NULL;
2743                 size_t snamelen = 0;
2744                 get_cname_target(iq->response->rep->rrsets[0], &sname,
2745                         &snamelen);
2746                 if(snamelen && dname_subdomain_c(sname, iq->response->rep->rrsets[0]->rk.dname)) {
2747                         /* DNAME to a subdomain loop; do not recurse */
2748                         type = RESPONSE_TYPE_ANSWER;
2749                 }
2750         } else if(type == RESPONSE_TYPE_CNAME &&
2751                 iq->qchase.qtype == LDNS_RR_TYPE_CNAME &&
2752                 iq->minimisation_state == MINIMISE_STATE &&
2753                 query_dname_compare(iq->qchase.qname, iq->qinfo_out.qname) == 0) {
2754                 /* The minimised query for full QTYPE and hidden QTYPE can be
2755                  * classified as CNAME response type, even when the original
2756                  * QTYPE=CNAME. This should be treated as answer response type.
2757                  */
2758                 type = RESPONSE_TYPE_ANSWER;
2759         }
2760
2761         /* handle each of the type cases */
2762         if(type == RESPONSE_TYPE_ANSWER) {
2763                 /* ANSWER type responses terminate the query algorithm,
2764                  * so they sent on their */
2765                 if(verbosity >= VERB_DETAIL) {
2766                         verbose(VERB_DETAIL, "query response was %s",
2767                                 FLAGS_GET_RCODE(iq->response->rep->flags)
2768                                 ==LDNS_RCODE_NXDOMAIN?"NXDOMAIN ANSWER":
2769                                 (iq->response->rep->an_numrrsets?"ANSWER":
2770                                 "nodata ANSWER"));
2771                 }
2772                 /* if qtype is DS, check we have the right level of answer,
2773                  * like grandchild answer but we need the middle, reject it */
2774                 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
2775                         && !(iq->chase_flags&BIT_RD)
2776                         && iter_ds_toolow(iq->response, iq->dp)
2777                         && iter_dp_cangodown(&iq->qchase, iq->dp)) {
2778                         /* close down outstanding requests to be discarded */
2779                         outbound_list_clear(&iq->outlist);
2780                         iq->num_current_queries = 0;
2781                         fptr_ok(fptr_whitelist_modenv_detach_subs(
2782                                 qstate->env->detach_subs));
2783                         (*qstate->env->detach_subs)(qstate);
2784                         iq->num_target_queries = 0;
2785                         return processDSNSFind(qstate, iq, id);
2786                 }
2787                 if(!qstate->no_cache_store)
2788                         iter_dns_store(qstate->env, &iq->response->qinfo,
2789                                 iq->response->rep, 0, qstate->prefetch_leeway,
2790                                 iq->dp&&iq->dp->has_parent_side_NS,
2791                                 qstate->region, qstate->query_flags);
2792                 /* close down outstanding requests to be discarded */
2793                 outbound_list_clear(&iq->outlist);
2794                 iq->num_current_queries = 0;
2795                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2796                         qstate->env->detach_subs));
2797                 (*qstate->env->detach_subs)(qstate);
2798                 iq->num_target_queries = 0;
2799                 if(qstate->reply)
2800                         sock_list_insert(&qstate->reply_origin,
2801                                 &qstate->reply->addr, qstate->reply->addrlen,
2802                                 qstate->region);
2803                 if(iq->minimisation_state != DONOT_MINIMISE_STATE
2804                         && !(iq->chase_flags & BIT_RD)) {
2805                         if(FLAGS_GET_RCODE(iq->response->rep->flags) !=
2806                                 LDNS_RCODE_NOERROR) {
2807                                 if(qstate->env->cfg->qname_minimisation_strict) {
2808                                         if(FLAGS_GET_RCODE(iq->response->rep->flags) ==
2809                                                 LDNS_RCODE_NXDOMAIN) {
2810                                                 iter_scrub_nxdomain(iq->response);
2811                                                 return final_state(iq);
2812                                         }
2813                                         return error_response(qstate, id,
2814                                                 LDNS_RCODE_SERVFAIL);
2815                                 }
2816                                 /* Best effort qname-minimisation.
2817                                  * Stop minimising and send full query when
2818                                  * RCODE is not NOERROR. */
2819                                 iq->minimisation_state = DONOT_MINIMISE_STATE;
2820                         }
2821                         if(FLAGS_GET_RCODE(iq->response->rep->flags) ==
2822                                 LDNS_RCODE_NXDOMAIN) {
2823                                 /* Stop resolving when NXDOMAIN is DNSSEC
2824                                  * signed. Based on assumption that nameservers
2825                                  * serving signed zones do not return NXDOMAIN
2826                                  * for empty-non-terminals. */
2827                                 if(iq->dnssec_expected)
2828                                         return final_state(iq);
2829                                 /* Make subrequest to validate intermediate
2830                                  * NXDOMAIN if harden-below-nxdomain is
2831                                  * enabled. */
2832                                 if(qstate->env->cfg->harden_below_nxdomain &&
2833                                         qstate->env->need_to_validate) {
2834                                         struct module_qstate* subq = NULL;
2835                                         log_query_info(VERB_QUERY,
2836                                                 "schedule NXDOMAIN validation:",
2837                                                 &iq->response->qinfo);
2838                                         if(!generate_sub_request(
2839                                                 iq->response->qinfo.qname,
2840                                                 iq->response->qinfo.qname_len,
2841                                                 iq->response->qinfo.qtype,
2842                                                 iq->response->qinfo.qclass,
2843                                                 qstate, id, iq,
2844                                                 INIT_REQUEST_STATE,
2845                                                 FINISHED_STATE, &subq, 1, 1))
2846                                                 verbose(VERB_ALGO,
2847                                                 "could not validate NXDOMAIN "
2848                                                 "response");
2849                                 }
2850                         }
2851                         return next_state(iq, QUERYTARGETS_STATE);
2852                 }
2853                 return final_state(iq);
2854         } else if(type == RESPONSE_TYPE_REFERRAL) {
2855                 /* REFERRAL type responses get a reset of the
2856                  * delegation point, and back to the QUERYTARGETS_STATE. */
2857                 verbose(VERB_DETAIL, "query response was REFERRAL");
2858
2859                 if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok) {
2860                         /* we have a referral, no ratelimit, we can send
2861                          * our queries to the given name */
2862                         infra_ratelimit_dec(qstate->env->infra_cache,
2863                                 iq->dp->name, iq->dp->namelen,
2864                                 *qstate->env->now);
2865                 }
2866
2867                 /* if hardened, only store referral if we asked for it */
2868                 if(!qstate->no_cache_store &&
2869                 (!qstate->env->cfg->harden_referral_path ||
2870                     (  qstate->qinfo.qtype == LDNS_RR_TYPE_NS
2871                         && (qstate->query_flags&BIT_RD)
2872                         && !(qstate->query_flags&BIT_CD)
2873                            /* we know that all other NS rrsets are scrubbed
2874                             * away, thus on referral only one is left.
2875                             * see if that equals the query name... */
2876                         && ( /* auth section, but sometimes in answer section*/
2877                           reply_find_rrset_section_ns(iq->response->rep,
2878                                 iq->qchase.qname, iq->qchase.qname_len,
2879                                 LDNS_RR_TYPE_NS, iq->qchase.qclass)
2880                           || reply_find_rrset_section_an(iq->response->rep,
2881                                 iq->qchase.qname, iq->qchase.qname_len,
2882                                 LDNS_RR_TYPE_NS, iq->qchase.qclass)
2883                           )
2884                     ))) {
2885                         /* Store the referral under the current query */
2886                         /* no prefetch-leeway, since its not the answer */
2887                         iter_dns_store(qstate->env, &iq->response->qinfo,
2888                                 iq->response->rep, 1, 0, 0, NULL, 0);
2889                         if(iq->store_parent_NS)
2890                                 iter_store_parentside_NS(qstate->env,
2891                                         iq->response->rep);
2892                         if(qstate->env->neg_cache)
2893                                 val_neg_addreferral(qstate->env->neg_cache,
2894                                         iq->response->rep, iq->dp->name);
2895                 }
2896                 /* store parent-side-in-zone-glue, if directly queried for */
2897                 if(!qstate->no_cache_store && iq->query_for_pside_glue
2898                         && !iq->pside_glue) {
2899                                 iq->pside_glue = reply_find_rrset(iq->response->rep,
2900                                         iq->qchase.qname, iq->qchase.qname_len,
2901                                         iq->qchase.qtype, iq->qchase.qclass);
2902                                 if(iq->pside_glue) {
2903                                         log_rrset_key(VERB_ALGO, "found parent-side "
2904                                                 "glue", iq->pside_glue);
2905                                         iter_store_parentside_rrset(qstate->env,
2906                                                 iq->pside_glue);
2907                                 }
2908                 }
2909
2910                 /* Reset the event state, setting the current delegation
2911                  * point to the referral. */
2912                 iq->deleg_msg = iq->response;
2913                 iq->dp = delegpt_from_message(iq->response, qstate->region);
2914                 if (qstate->env->cfg->qname_minimisation)
2915                         iq->minimisation_state = INIT_MINIMISE_STATE;
2916                 if(!iq->dp) {
2917                         errinf(qstate, "malloc failure, for delegation point");
2918                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2919                 }
2920                 if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
2921                         qstate->region, iq->dp)) {
2922                         errinf(qstate, "malloc failure, copy extra info into delegation point");
2923                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2924                 }
2925                 if(iq->store_parent_NS && query_dname_compare(iq->dp->name,
2926                         iq->store_parent_NS->name) == 0)
2927                         iter_merge_retry_counts(iq->dp, iq->store_parent_NS);
2928                 delegpt_log(VERB_ALGO, iq->dp);
2929                 /* Count this as a referral. */
2930                 iq->referral_count++;
2931                 iq->sent_count = 0;
2932                 iq->dp_target_count = 0;
2933                 /* see if the next dp is a trust anchor, or a DS was sent
2934                  * along, indicating dnssec is expected for next zone */
2935                 iq->dnssec_expected = iter_indicates_dnssec(qstate->env,
2936                         iq->dp, iq->response, iq->qchase.qclass);
2937                 /* if dnssec, validating then also fetch the key for the DS */
2938                 if(iq->dnssec_expected && qstate->env->cfg->prefetch_key &&
2939                         !(qstate->query_flags&BIT_CD))
2940                         generate_dnskey_prefetch(qstate, iq, id);
2941
2942                 /* spawn off NS and addr to auth servers for the NS we just
2943                  * got in the referral. This gets authoritative answer
2944                  * (answer section trust level) rrset.
2945                  * right after, we detach the subs, answer goes to cache. */
2946                 if(qstate->env->cfg->harden_referral_path)
2947                         generate_ns_check(qstate, iq, id);
2948
2949                 /* stop current outstanding queries.
2950                  * FIXME: should the outstanding queries be waited for and
2951                  * handled? Say by a subquery that inherits the outbound_entry.
2952                  */
2953                 outbound_list_clear(&iq->outlist);
2954                 iq->num_current_queries = 0;
2955                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2956                         qstate->env->detach_subs));
2957                 (*qstate->env->detach_subs)(qstate);
2958                 iq->num_target_queries = 0;
2959                 verbose(VERB_ALGO, "cleared outbound list for next round");
2960                 return next_state(iq, QUERYTARGETS_STATE);
2961         } else if(type == RESPONSE_TYPE_CNAME) {
2962                 uint8_t* sname = NULL;
2963                 size_t snamelen = 0;
2964                 /* CNAME type responses get a query restart (i.e., get a
2965                  * reset of the query state and go back to INIT_REQUEST_STATE).
2966                  */
2967                 verbose(VERB_DETAIL, "query response was CNAME");
2968                 if(verbosity >= VERB_ALGO)
2969                         log_dns_msg("cname msg", &iq->response->qinfo,
2970                                 iq->response->rep);
2971                 /* if qtype is DS, check we have the right level of answer,
2972                  * like grandchild answer but we need the middle, reject it */
2973                 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
2974                         && !(iq->chase_flags&BIT_RD)
2975                         && iter_ds_toolow(iq->response, iq->dp)
2976                         && iter_dp_cangodown(&iq->qchase, iq->dp)) {
2977                         outbound_list_clear(&iq->outlist);
2978                         iq->num_current_queries = 0;
2979                         fptr_ok(fptr_whitelist_modenv_detach_subs(
2980                                 qstate->env->detach_subs));
2981                         (*qstate->env->detach_subs)(qstate);
2982                         iq->num_target_queries = 0;
2983                         return processDSNSFind(qstate, iq, id);
2984                 }
2985                 /* Process the CNAME response. */
2986                 if(!handle_cname_response(qstate, iq, iq->response,
2987                         &sname, &snamelen)) {
2988                         errinf(qstate, "malloc failure, CNAME info");
2989                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2990                 }
2991                 /* cache the CNAME response under the current query */
2992                 /* NOTE : set referral=1, so that rrsets get stored but not
2993                  * the partial query answer (CNAME only). */
2994                 /* prefetchleeway applied because this updates answer parts */
2995                 if(!qstate->no_cache_store)
2996                         iter_dns_store(qstate->env, &iq->response->qinfo,
2997                                 iq->response->rep, 1, qstate->prefetch_leeway,
2998                                 iq->dp&&iq->dp->has_parent_side_NS, NULL,
2999                                 qstate->query_flags);
3000                 /* set the current request's qname to the new value. */
3001                 iq->qchase.qname = sname;
3002                 iq->qchase.qname_len = snamelen;
3003                 /* Clear the query state, since this is a query restart. */
3004                 iq->deleg_msg = NULL;
3005                 iq->dp = NULL;
3006                 iq->dsns_point = NULL;
3007                 iq->auth_zone_response = 0;
3008                 iq->sent_count = 0;
3009                 iq->dp_target_count = 0;
3010                 if(iq->minimisation_state != MINIMISE_STATE)
3011                         /* Only count as query restart when it is not an extra
3012                          * query as result of qname minimisation. */
3013                         iq->query_restart_count++;
3014                 if(qstate->env->cfg->qname_minimisation)
3015                         iq->minimisation_state = INIT_MINIMISE_STATE;
3016
3017                 /* stop current outstanding queries.
3018                  * FIXME: should the outstanding queries be waited for and
3019                  * handled? Say by a subquery that inherits the outbound_entry.
3020                  */
3021                 outbound_list_clear(&iq->outlist);
3022                 iq->num_current_queries = 0;
3023                 fptr_ok(fptr_whitelist_modenv_detach_subs(
3024                         qstate->env->detach_subs));
3025                 (*qstate->env->detach_subs)(qstate);
3026                 iq->num_target_queries = 0;
3027                 if(qstate->reply)
3028                         sock_list_insert(&qstate->reply_origin,
3029                                 &qstate->reply->addr, qstate->reply->addrlen,
3030                                 qstate->region);
3031                 verbose(VERB_ALGO, "cleared outbound list for query restart");
3032                 /* go to INIT_REQUEST_STATE for new qname. */
3033                 return next_state(iq, INIT_REQUEST_STATE);
3034         } else if(type == RESPONSE_TYPE_LAME) {
3035                 /* Cache the LAMEness. */
3036                 verbose(VERB_DETAIL, "query response was %sLAME",
3037                         dnsseclame?"DNSSEC ":"");
3038                 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) {
3039                         log_err("mark lame: mismatch in qname and dpname");
3040                         /* throwaway this reply below */
3041                 } else if(qstate->reply) {
3042                         /* need addr for lameness cache, but we may have
3043                          * gotten this from cache, so test to be sure */
3044                         if(!infra_set_lame(qstate->env->infra_cache,
3045                                 &qstate->reply->addr, qstate->reply->addrlen,
3046                                 iq->dp->name, iq->dp->namelen,
3047                                 *qstate->env->now, dnsseclame, 0,
3048                                 iq->qchase.qtype))
3049                                 log_err("mark host lame: out of memory");
3050                 }
3051         } else if(type == RESPONSE_TYPE_REC_LAME) {
3052                 /* Cache the LAMEness. */
3053                 verbose(VERB_DETAIL, "query response REC_LAME: "
3054                         "recursive but not authoritative server");
3055                 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) {
3056                         log_err("mark rec_lame: mismatch in qname and dpname");
3057                         /* throwaway this reply below */
3058                 } else if(qstate->reply) {
3059                         /* need addr for lameness cache, but we may have
3060                          * gotten this from cache, so test to be sure */
3061                         verbose(VERB_DETAIL, "mark as REC_LAME");
3062                         if(!infra_set_lame(qstate->env->infra_cache,
3063                                 &qstate->reply->addr, qstate->reply->addrlen,
3064                                 iq->dp->name, iq->dp->namelen,
3065                                 *qstate->env->now, 0, 1, iq->qchase.qtype))
3066                                 log_err("mark host lame: out of memory");
3067                 }
3068         } else if(type == RESPONSE_TYPE_THROWAWAY) {
3069                 /* LAME and THROWAWAY responses are handled the same way.
3070                  * In this case, the event is just sent directly back to
3071                  * the QUERYTARGETS_STATE without resetting anything,
3072                  * because, clearly, the next target must be tried. */
3073                 verbose(VERB_DETAIL, "query response was THROWAWAY");
3074         } else {
3075                 log_warn("A query response came back with an unknown type: %d",
3076                         (int)type);
3077         }
3078
3079         /* LAME, THROWAWAY and "unknown" all end up here.
3080          * Recycle to the QUERYTARGETS state to hopefully try a
3081          * different target. */
3082         if (qstate->env->cfg->qname_minimisation &&
3083                 !qstate->env->cfg->qname_minimisation_strict)
3084                 iq->minimisation_state = DONOT_MINIMISE_STATE;
3085         if(iq->auth_zone_response) {
3086                 /* can we fallback? */
3087                 iq->auth_zone_response = 0;
3088                 if(!auth_zones_can_fallback(qstate->env->auth_zones,
3089                         iq->dp->name, iq->dp->namelen, qstate->qinfo.qclass)) {
3090                         verbose(VERB_ALGO, "auth zone response bad, and no"
3091                                 " fallback possible, servfail");
3092                         errinf_dname(qstate, "response is bad, no fallback, "
3093                                 "for auth zone", iq->dp->name);
3094                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3095                 }
3096                 verbose(VERB_ALGO, "auth zone response was bad, "
3097                         "fallback enabled");
3098                 iq->auth_zone_avoid = 1;
3099                 if(iq->dp->auth_dp) {
3100                         /* we are using a dp for the auth zone, with no
3101                          * nameservers, get one first */
3102                         iq->dp = NULL;
3103                         return next_state(iq, INIT_REQUEST_STATE);
3104                 }
3105         }
3106         return next_state(iq, QUERYTARGETS_STATE);
3107 }
3108
3109 /**
3110  * Return priming query results to interested super querystates.
3111  *
3112  * Sets the delegation point and delegation message (not nonRD queries).
3113  * This is a callback from walk_supers.
3114  *
3115  * @param qstate: priming query state that finished.
3116  * @param id: module id.
3117  * @param forq: the qstate for which priming has been done.
3118  */
3119 static void
3120 prime_supers(struct module_qstate* qstate, int id, struct module_qstate* forq)
3121 {
3122         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
3123         struct delegpt* dp = NULL;
3124
3125         log_assert(qstate->is_priming || foriq->wait_priming_stub);
3126         log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR);
3127         /* Convert our response to a delegation point */
3128         dp = delegpt_from_message(qstate->return_msg, forq->region);
3129         if(!dp) {
3130                 /* if there is no convertable delegation point, then
3131                  * the ANSWER type was (presumably) a negative answer. */
3132                 verbose(VERB_ALGO, "prime response was not a positive "
3133                         "ANSWER; failing");
3134                 foriq->dp = NULL;
3135                 foriq->state = QUERYTARGETS_STATE;
3136                 return;
3137         }
3138
3139         log_query_info(VERB_DETAIL, "priming successful for", &qstate->qinfo);
3140         delegpt_log(VERB_ALGO, dp);
3141         foriq->dp = dp;
3142         foriq->deleg_msg = dns_copy_msg(qstate->return_msg, forq->region);
3143         if(!foriq->deleg_msg) {
3144                 log_err("copy prime response: out of memory");
3145                 foriq->dp = NULL;
3146                 foriq->state = QUERYTARGETS_STATE;
3147                 return;
3148         }
3149
3150         /* root priming responses go to init stage 2, priming stub
3151          * responses to to stage 3. */
3152         if(foriq->wait_priming_stub) {
3153                 foriq->state = INIT_REQUEST_3_STATE;
3154                 foriq->wait_priming_stub = 0;
3155         } else  foriq->state = INIT_REQUEST_2_STATE;
3156         /* because we are finished, the parent will be reactivated */
3157 }
3158
3159 /**
3160  * This handles the response to a priming query. This is used to handle both
3161  * root and stub priming responses. This is basically the equivalent of the
3162  * QUERY_RESP_STATE, but will not handle CNAME responses and will treat
3163  * REFERRALs as ANSWERS. It will also update and reactivate the originating
3164  * event.
3165  *
3166  * @param qstate: query state.
3167  * @param id: module id.
3168  * @return true if the event needs more immediate processing, false if not.
3169  *         This state always returns false.
3170  */
3171 static int
3172 processPrimeResponse(struct module_qstate* qstate, int id)
3173 {
3174         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3175         enum response_type type;
3176         iq->response->rep->flags &= ~(BIT_RD|BIT_RA); /* ignore rec-lame */
3177         type = response_type_from_server(
3178                 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd),
3179                 iq->response, &iq->qchase, iq->dp);
3180         if(type == RESPONSE_TYPE_ANSWER) {
3181                 qstate->return_rcode = LDNS_RCODE_NOERROR;
3182                 qstate->return_msg = iq->response;
3183         } else {
3184                 errinf(qstate, "prime response did not get an answer");
3185                 errinf_dname(qstate, "for", qstate->qinfo.qname);
3186                 qstate->return_rcode = LDNS_RCODE_SERVFAIL;
3187                 qstate->return_msg = NULL;
3188         }
3189
3190         /* validate the root or stub after priming (if enabled).
3191          * This is the same query as the prime query, but with validation.
3192          * Now that we are primed, the additional queries that validation
3193          * may need can be resolved, such as DLV. */
3194         if(qstate->env->cfg->harden_referral_path) {
3195                 struct module_qstate* subq = NULL;
3196                 log_nametypeclass(VERB_ALGO, "schedule prime validation",
3197                         qstate->qinfo.qname, qstate->qinfo.qtype,
3198                         qstate->qinfo.qclass);
3199                 if(!generate_sub_request(qstate->qinfo.qname,
3200                         qstate->qinfo.qname_len, qstate->qinfo.qtype,
3201                         qstate->qinfo.qclass, qstate, id, iq,
3202                         INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1, 0)) {
3203                         verbose(VERB_ALGO, "could not generate prime check");
3204                 }
3205                 generate_a_aaaa_check(qstate, iq, id);
3206         }
3207
3208         /* This event is finished. */
3209         qstate->ext_state[id] = module_finished;
3210         return 0;
3211 }
3212
3213 /**
3214  * Do final processing on responses to target queries. Events reach this
3215  * state after the iterative resolution algorithm terminates. This state is
3216  * responsible for reactivating the original event, and housekeeping related
3217  * to received target responses (caching, updating the current delegation
3218  * point, etc).
3219  * Callback from walk_supers for every super state that is interested in
3220  * the results from this query.
3221  *
3222  * @param qstate: query state.
3223  * @param id: module id.
3224  * @param forq: super query state.
3225  */
3226 static void
3227 processTargetResponse(struct module_qstate* qstate, int id,
3228         struct module_qstate* forq)
3229 {
3230         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
3231         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3232         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
3233         struct ub_packed_rrset_key* rrset;
3234         struct delegpt_ns* dpns;
3235         log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR);
3236
3237         foriq->state = QUERYTARGETS_STATE;
3238         log_query_info(VERB_ALGO, "processTargetResponse", &qstate->qinfo);
3239         log_query_info(VERB_ALGO, "processTargetResponse super", &forq->qinfo);
3240
3241         /* Tell the originating event that this target query has finished
3242          * (regardless if it succeeded or not). */
3243         foriq->num_target_queries--;
3244
3245         /* check to see if parent event is still interested (in orig name).  */
3246         if(!foriq->dp) {
3247                 verbose(VERB_ALGO, "subq: parent not interested, was reset");
3248                 return; /* not interested anymore */
3249         }
3250         dpns = delegpt_find_ns(foriq->dp, qstate->qinfo.qname,
3251                         qstate->qinfo.qname_len);
3252         if(!dpns) {
3253                 /* If not interested, just stop processing this event */
3254                 verbose(VERB_ALGO, "subq: parent not interested anymore");
3255                 /* could be because parent was jostled out of the cache,
3256                    and a new identical query arrived, that does not want it*/
3257                 return;
3258         }
3259
3260         /* if iq->query_for_pside_glue then add the pside_glue (marked lame) */
3261         if(iq->pside_glue) {
3262                 /* if the pside_glue is NULL, then it could not be found,
3263                  * the done_pside is already set when created and a cache
3264                  * entry created in processFinished so nothing to do here */
3265                 log_rrset_key(VERB_ALGO, "add parentside glue to dp",
3266                         iq->pside_glue);
3267                 if(!delegpt_add_rrset(foriq->dp, forq->region,
3268                         iq->pside_glue, 1, NULL))
3269                         log_err("out of memory adding pside glue");
3270         }
3271
3272         /* This response is relevant to the current query, so we
3273          * add (attempt to add, anyway) this target(s) and reactivate
3274          * the original event.
3275          * NOTE: we could only look for the AnswerRRset if the
3276          * response type was ANSWER. */
3277         rrset = reply_find_answer_rrset(&iq->qchase, qstate->return_msg->rep);
3278         if(rrset) {
3279                 int additions = 0;
3280                 /* if CNAMEs have been followed - add new NS to delegpt. */
3281                 /* BTW. RFC 1918 says NS should not have got CNAMEs. Robust. */
3282                 if(!delegpt_find_ns(foriq->dp, rrset->rk.dname,
3283                         rrset->rk.dname_len)) {
3284                         /* if dpns->lame then set newcname ns lame too */
3285                         if(!delegpt_add_ns(foriq->dp, forq->region,
3286                                 rrset->rk.dname, dpns->lame))
3287                                 log_err("out of memory adding cnamed-ns");
3288                 }
3289                 /* if dpns->lame then set the address(es) lame too */
3290                 if(!delegpt_add_rrset(foriq->dp, forq->region, rrset,
3291                         dpns->lame, &additions))
3292                         log_err("out of memory adding targets");
3293                 if(!additions) {
3294                         /* no new addresses, increase the nxns counter, like
3295                          * this could be a list of wildcards with no new
3296                          * addresses */
3297                         target_count_increase_nx(foriq, 1);
3298                 }
3299                 verbose(VERB_ALGO, "added target response");
3300                 delegpt_log(VERB_ALGO, foriq->dp);
3301         } else {
3302                 verbose(VERB_ALGO, "iterator TargetResponse failed");
3303                 delegpt_mark_neg(dpns, qstate->qinfo.qtype);
3304                 dpns->resolved = 1; /* fail the target */
3305                 if((dpns->got4 == 2 || !ie->supports_ipv4) &&
3306                         (dpns->got6 == 2 || !ie->supports_ipv6))
3307                         target_count_increase_nx(foriq, 1);
3308         }
3309 }
3310
3311 /**
3312  * Process response for DS NS Find queries, that attempt to find the delegation
3313  * point where we ask the DS query from.
3314  *
3315  * @param qstate: query state.
3316  * @param id: module id.
3317  * @param forq: super query state.
3318  */
3319 static void
3320 processDSNSResponse(struct module_qstate* qstate, int id,
3321         struct module_qstate* forq)
3322 {
3323         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
3324
3325         /* if the finished (iq->response) query has no NS set: continue
3326          * up to look for the right dp; nothing to change, do DPNSstate */
3327         if(qstate->return_rcode != LDNS_RCODE_NOERROR)
3328                 return; /* seek further */
3329         /* find the NS RRset (without allowing CNAMEs) */
3330         if(!reply_find_rrset(qstate->return_msg->rep, qstate->qinfo.qname,
3331                 qstate->qinfo.qname_len, LDNS_RR_TYPE_NS,
3332                 qstate->qinfo.qclass)){
3333                 return; /* seek further */
3334         }
3335
3336         /* else, store as DP and continue at querytargets */
3337         foriq->state = QUERYTARGETS_STATE;
3338         foriq->dp = delegpt_from_message(qstate->return_msg, forq->region);
3339         if(!foriq->dp) {
3340                 log_err("out of memory in dsns dp alloc");
3341                 errinf(qstate, "malloc failure, in DS search");
3342                 return; /* dp==NULL in QUERYTARGETS makes SERVFAIL */
3343         }
3344         /* success, go query the querytargets in the new dp (and go down) */
3345 }
3346
3347 /**
3348  * Process response for qclass=ANY queries for a particular class.
3349  * Append to result or error-exit.
3350  *
3351  * @param qstate: query state.
3352  * @param id: module id.
3353  * @param forq: super query state.
3354  */
3355 static void
3356 processClassResponse(struct module_qstate* qstate, int id,
3357         struct module_qstate* forq)
3358 {
3359         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
3360         struct dns_msg* from = qstate->return_msg;
3361         log_query_info(VERB_ALGO, "processClassResponse", &qstate->qinfo);
3362         log_query_info(VERB_ALGO, "processClassResponse super", &forq->qinfo);
3363         if(qstate->return_rcode != LDNS_RCODE_NOERROR) {
3364                 /* cause servfail for qclass ANY query */
3365                 foriq->response = NULL;
3366                 foriq->state = FINISHED_STATE;
3367                 return;
3368         }
3369         /* append result */
3370         if(!foriq->response) {
3371                 /* allocate the response: copy RCODE, sec_state */
3372                 foriq->response = dns_copy_msg(from, forq->region);
3373                 if(!foriq->response) {
3374                         log_err("malloc failed for qclass ANY response");
3375                         foriq->state = FINISHED_STATE;
3376                         return;
3377                 }
3378                 foriq->response->qinfo.qclass = forq->qinfo.qclass;
3379                 /* qclass ANY does not receive the AA flag on replies */
3380                 foriq->response->rep->authoritative = 0;
3381         } else {
3382                 struct dns_msg* to = foriq->response;
3383                 /* add _from_ this response _to_ existing collection */
3384                 /* if there are records, copy RCODE */
3385                 /* lower sec_state if this message is lower */
3386                 if(from->rep->rrset_count != 0) {
3387                         size_t n = from->rep->rrset_count+to->rep->rrset_count;
3388                         struct ub_packed_rrset_key** dest, **d;
3389                         /* copy appropriate rcode */
3390                         to->rep->flags = from->rep->flags;
3391                         /* copy rrsets */
3392                         if(from->rep->rrset_count > RR_COUNT_MAX ||
3393                                 to->rep->rrset_count > RR_COUNT_MAX) {
3394                                 log_err("malloc failed (too many rrsets) in collect ANY");
3395                                 foriq->state = FINISHED_STATE;
3396                                 return; /* integer overflow protection */
3397                         }
3398                         dest = regional_alloc(forq->region, sizeof(dest[0])*n);
3399                         if(!dest) {
3400                                 log_err("malloc failed in collect ANY");
3401                                 foriq->state = FINISHED_STATE;
3402                                 return;
3403                         }
3404                         d = dest;
3405                         /* copy AN */
3406                         memcpy(dest, to->rep->rrsets, to->rep->an_numrrsets
3407                                 * sizeof(dest[0]));
3408                         dest += to->rep->an_numrrsets;
3409                         memcpy(dest, from->rep->rrsets, from->rep->an_numrrsets
3410                                 * sizeof(dest[0]));
3411                         dest += from->rep->an_numrrsets;
3412                         /* copy NS */
3413                         memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets,
3414                                 to->rep->ns_numrrsets * sizeof(dest[0]));
3415                         dest += to->rep->ns_numrrsets;
3416                         memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets,
3417                                 from->rep->ns_numrrsets * sizeof(dest[0]));
3418                         dest += from->rep->ns_numrrsets;
3419                         /* copy AR */
3420                         memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets+
3421                                 to->rep->ns_numrrsets,
3422                                 to->rep->ar_numrrsets * sizeof(dest[0]));
3423                         dest += to->rep->ar_numrrsets;
3424                         memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets+
3425                                 from->rep->ns_numrrsets,
3426                                 from->rep->ar_numrrsets * sizeof(dest[0]));
3427                         /* update counts */
3428                         to->rep->rrsets = d;
3429                         to->rep->an_numrrsets += from->rep->an_numrrsets;
3430                         to->rep->ns_numrrsets += from->rep->ns_numrrsets;
3431                         to->rep->ar_numrrsets += from->rep->ar_numrrsets;
3432                         to->rep->rrset_count = n;
3433                 }
3434                 if(from->rep->security < to->rep->security) /* lowest sec */
3435                         to->rep->security = from->rep->security;
3436                 if(from->rep->qdcount != 0) /* insert qd if appropriate */
3437                         to->rep->qdcount = from->rep->qdcount;
3438                 if(from->rep->ttl < to->rep->ttl) /* use smallest TTL */
3439                         to->rep->ttl = from->rep->ttl;
3440                 if(from->rep->prefetch_ttl < to->rep->prefetch_ttl)
3441                         to->rep->prefetch_ttl = from->rep->prefetch_ttl;
3442                 if(from->rep->serve_expired_ttl < to->rep->serve_expired_ttl)
3443                         to->rep->serve_expired_ttl = from->rep->serve_expired_ttl;
3444         }
3445         /* are we done? */
3446         foriq->num_current_queries --;
3447         if(foriq->num_current_queries == 0)
3448                 foriq->state = FINISHED_STATE;
3449 }
3450
3451 /**
3452  * Collect class ANY responses and make them into one response.  This
3453  * state is started and it creates queries for all classes (that have
3454  * root hints).  The answers are then collected.
3455  *
3456  * @param qstate: query state.
3457  * @param id: module id.
3458  * @return true if the event needs more immediate processing, false if not.
3459  */
3460 static int
3461 processCollectClass(struct module_qstate* qstate, int id)
3462 {
3463         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3464         struct module_qstate* subq;
3465         /* If qchase.qclass == 0 then send out queries for all classes.
3466          * Otherwise, do nothing (wait for all answers to arrive and the
3467          * processClassResponse to put them together, and that moves us
3468          * towards the Finished state when done. */
3469         if(iq->qchase.qclass == 0) {
3470                 uint16_t c = 0;
3471                 iq->qchase.qclass = LDNS_RR_CLASS_ANY;
3472                 while(iter_get_next_root(qstate->env->hints,
3473                         qstate->env->fwds, &c)) {
3474                         /* generate query for this class */
3475                         log_nametypeclass(VERB_ALGO, "spawn collect query",
3476                                 qstate->qinfo.qname, qstate->qinfo.qtype, c);
3477                         if(!generate_sub_request(qstate->qinfo.qname,
3478                                 qstate->qinfo.qname_len, qstate->qinfo.qtype,
3479                                 c, qstate, id, iq, INIT_REQUEST_STATE,
3480                                 FINISHED_STATE, &subq,
3481                                 (int)!(qstate->query_flags&BIT_CD), 0)) {
3482                                 errinf(qstate, "could not generate class ANY"
3483                                         " lookup query");
3484                                 return error_response(qstate, id,
3485                                         LDNS_RCODE_SERVFAIL);
3486                         }
3487                         /* ignore subq, no special init required */
3488                         iq->num_current_queries ++;
3489                         if(c == 0xffff)
3490                                 break;
3491                         else c++;
3492                 }
3493                 /* if no roots are configured at all, return */
3494                 if(iq->num_current_queries == 0) {
3495                         verbose(VERB_ALGO, "No root hints or fwds, giving up "
3496                                 "on qclass ANY");
3497                         return error_response(qstate, id, LDNS_RCODE_REFUSED);
3498                 }
3499                 /* return false, wait for queries to return */
3500         }
3501         /* if woke up here because of an answer, wait for more answers */
3502         return 0;
3503 }
3504
3505 /**
3506  * This handles the final state for first-tier responses (i.e., responses to
3507  * externally generated queries).
3508  *
3509  * @param qstate: query state.
3510  * @param iq: iterator query state.
3511  * @param id: module id.
3512  * @return true if the event needs more processing, false if not. Since this
3513  *         is the final state for an event, it always returns false.
3514  */
3515 static int
3516 processFinished(struct module_qstate* qstate, struct iter_qstate* iq,
3517         int id)
3518 {
3519         log_query_info(VERB_QUERY, "finishing processing for",
3520                 &qstate->qinfo);
3521
3522         /* store negative cache element for parent side glue. */
3523         if(!qstate->no_cache_store && iq->query_for_pside_glue
3524                 && !iq->pside_glue)
3525                         iter_store_parentside_neg(qstate->env, &qstate->qinfo,
3526                                 iq->deleg_msg?iq->deleg_msg->rep:
3527                                 (iq->response?iq->response->rep:NULL));
3528         if(!iq->response) {
3529                 verbose(VERB_ALGO, "No response is set, servfail");
3530                 errinf(qstate, "(no response found at query finish)");
3531                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3532         }
3533
3534         /* Make sure that the RA flag is set (since the presence of
3535          * this module means that recursion is available) */
3536         iq->response->rep->flags |= BIT_RA;
3537
3538         /* Clear the AA flag */
3539         /* FIXME: does this action go here or in some other module? */
3540         iq->response->rep->flags &= ~BIT_AA;
3541
3542         /* make sure QR flag is on */
3543         iq->response->rep->flags |= BIT_QR;
3544
3545         /* we have finished processing this query */
3546         qstate->ext_state[id] = module_finished;
3547
3548         /* TODO:  we are using a private TTL, trim the response. */
3549         /* if (mPrivateTTL > 0){IterUtils.setPrivateTTL(resp, mPrivateTTL); } */
3550
3551         /* prepend any items we have accumulated */
3552         if(iq->an_prepend_list || iq->ns_prepend_list) {
3553                 if(!iter_prepend(iq, iq->response, qstate->region)) {
3554                         log_err("prepend rrsets: out of memory");
3555                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3556                 }
3557                 /* reset the query name back */
3558                 iq->response->qinfo = qstate->qinfo;
3559                 /* the security state depends on the combination */
3560                 iq->response->rep->security = sec_status_unchecked;
3561                 /* store message with the finished prepended items,
3562                  * but only if we did recursion. The nonrecursion referral
3563                  * from cache does not need to be stored in the msg cache. */
3564                 if(!qstate->no_cache_store && qstate->query_flags&BIT_RD) {
3565                         iter_dns_store(qstate->env, &qstate->qinfo,
3566                                 iq->response->rep, 0, qstate->prefetch_leeway,
3567                                 iq->dp&&iq->dp->has_parent_side_NS,
3568                                 qstate->region, qstate->query_flags);
3569                 }
3570         }
3571         qstate->return_rcode = LDNS_RCODE_NOERROR;
3572         qstate->return_msg = iq->response;
3573         return 0;
3574 }
3575
3576 /*
3577  * Return priming query results to interested super querystates.
3578  *
3579  * Sets the delegation point and delegation message (not nonRD queries).
3580  * This is a callback from walk_supers.
3581  *
3582  * @param qstate: query state that finished.
3583  * @param id: module id.
3584  * @param super: the qstate to inform.
3585  */
3586 void
3587 iter_inform_super(struct module_qstate* qstate, int id,
3588         struct module_qstate* super)
3589 {
3590         if(!qstate->is_priming && super->qinfo.qclass == LDNS_RR_CLASS_ANY)
3591                 processClassResponse(qstate, id, super);
3592         else if(super->qinfo.qtype == LDNS_RR_TYPE_DS && ((struct iter_qstate*)
3593                 super->minfo[id])->state == DSNS_FIND_STATE)
3594                 processDSNSResponse(qstate, id, super);
3595         else if(qstate->return_rcode != LDNS_RCODE_NOERROR)
3596                 error_supers(qstate, id, super);
3597         else if(qstate->is_priming)
3598                 prime_supers(qstate, id, super);
3599         else    processTargetResponse(qstate, id, super);
3600 }
3601
3602 /**
3603  * Handle iterator state.
3604  * Handle events. This is the real processing loop for events, responsible
3605  * for moving events through the various states. If a processing method
3606  * returns true, then it will be advanced to the next state. If false, then
3607  * processing will stop.
3608  *
3609  * @param qstate: query state.
3610  * @param ie: iterator shared global environment.
3611  * @param iq: iterator query state.
3612  * @param id: module id.
3613  */
3614 static void
3615 iter_handle(struct module_qstate* qstate, struct iter_qstate* iq,
3616         struct iter_env* ie, int id)
3617 {
3618         int cont = 1;
3619         while(cont) {
3620                 verbose(VERB_ALGO, "iter_handle processing q with state %s",
3621                         iter_state_to_string(iq->state));
3622                 switch(iq->state) {
3623                         case INIT_REQUEST_STATE:
3624                                 cont = processInitRequest(qstate, iq, ie, id);
3625                                 break;
3626                         case INIT_REQUEST_2_STATE:
3627                                 cont = processInitRequest2(qstate, iq, id);
3628                                 break;
3629                         case INIT_REQUEST_3_STATE:
3630                                 cont = processInitRequest3(qstate, iq, id);
3631                                 break;
3632                         case QUERYTARGETS_STATE:
3633                                 cont = processQueryTargets(qstate, iq, ie, id);
3634                                 break;
3635                         case QUERY_RESP_STATE:
3636                                 cont = processQueryResponse(qstate, iq, id);
3637                                 break;
3638                         case PRIME_RESP_STATE:
3639                                 cont = processPrimeResponse(qstate, id);
3640                                 break;
3641                         case COLLECT_CLASS_STATE:
3642                                 cont = processCollectClass(qstate, id);
3643                                 break;
3644                         case DSNS_FIND_STATE:
3645                                 cont = processDSNSFind(qstate, iq, id);
3646                                 break;
3647                         case FINISHED_STATE:
3648                                 cont = processFinished(qstate, iq, id);
3649                                 break;
3650                         default:
3651                                 log_warn("iterator: invalid state: %d",
3652                                         iq->state);
3653                                 cont = 0;
3654                                 break;
3655                 }
3656         }
3657 }
3658
3659 /**
3660  * This is the primary entry point for processing request events. Note that
3661  * this method should only be used by external modules.
3662  * @param qstate: query state.
3663  * @param ie: iterator shared global environment.
3664  * @param iq: iterator query state.
3665  * @param id: module id.
3666  */
3667 static void
3668 process_request(struct module_qstate* qstate, struct iter_qstate* iq,
3669         struct iter_env* ie, int id)
3670 {
3671         /* external requests start in the INIT state, and finish using the
3672          * FINISHED state. */
3673         iq->state = INIT_REQUEST_STATE;
3674         iq->final_state = FINISHED_STATE;
3675         verbose(VERB_ALGO, "process_request: new external request event");
3676         iter_handle(qstate, iq, ie, id);
3677 }
3678
3679 /** process authoritative server reply */
3680 static void
3681 process_response(struct module_qstate* qstate, struct iter_qstate* iq,
3682         struct iter_env* ie, int id, struct outbound_entry* outbound,
3683         enum module_ev event)
3684 {
3685         struct msg_parse* prs;
3686         struct edns_data edns;
3687         sldns_buffer* pkt;
3688
3689         verbose(VERB_ALGO, "process_response: new external response event");
3690         iq->response = NULL;
3691         iq->state = QUERY_RESP_STATE;
3692         if(event == module_event_noreply || event == module_event_error) {
3693                 if(event == module_event_noreply && iq->sent_count >= 3 &&
3694                         qstate->env->cfg->use_caps_bits_for_id &&
3695                         !iq->caps_fallback && !is_caps_whitelisted(ie, iq)) {
3696                         /* start fallback */
3697                         iq->caps_fallback = 1;
3698                         iq->caps_server = 0;
3699                         iq->caps_reply = NULL;
3700                         iq->caps_response = NULL;
3701                         iq->caps_minimisation_state = DONOT_MINIMISE_STATE;
3702                         iq->state = QUERYTARGETS_STATE;
3703                         iq->num_current_queries--;
3704                         /* need fresh attempts for the 0x20 fallback, if
3705                          * that was the cause for the failure */
3706                         iter_dec_attempts(iq->dp, 3);
3707                         verbose(VERB_DETAIL, "Capsforid: timeouts, starting fallback");
3708                         goto handle_it;
3709                 }
3710                 goto handle_it;
3711         }
3712         if( (event != module_event_reply && event != module_event_capsfail)
3713                 || !qstate->reply) {
3714                 log_err("Bad event combined with response");
3715                 outbound_list_remove(&iq->outlist, outbound);
3716                 errinf(qstate, "module iterator received wrong internal event with a response message");
3717                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3718                 return;
3719         }
3720
3721         /* parse message */
3722         prs = (struct msg_parse*)regional_alloc(qstate->env->scratch,
3723                 sizeof(struct msg_parse));
3724         if(!prs) {
3725                 log_err("out of memory on incoming message");
3726                 /* like packet got dropped */
3727                 goto handle_it;
3728         }
3729         memset(prs, 0, sizeof(*prs));
3730         memset(&edns, 0, sizeof(edns));
3731         pkt = qstate->reply->c->buffer;
3732         sldns_buffer_set_position(pkt, 0);
3733         if(parse_packet(pkt, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) {
3734                 verbose(VERB_ALGO, "parse error on reply packet");
3735                 goto handle_it;
3736         }
3737         /* edns is not examined, but removed from message to help cache */
3738         if(parse_extract_edns(prs, &edns, qstate->env->scratch) !=
3739                 LDNS_RCODE_NOERROR)
3740                 goto handle_it;
3741
3742         /* Copy the edns options we may got from the back end */
3743         if(edns.opt_list) {
3744                 qstate->edns_opts_back_in = edns_opt_copy_region(edns.opt_list,
3745                         qstate->region);
3746                 if(!qstate->edns_opts_back_in) {
3747                         log_err("out of memory on incoming message");
3748                         /* like packet got dropped */
3749                         goto handle_it;
3750                 }
3751                 if(!inplace_cb_edns_back_parsed_call(qstate->env, qstate)) {
3752                         log_err("unable to call edns_back_parsed callback");
3753                         goto handle_it;
3754                 }
3755         }
3756
3757         /* remove CD-bit, we asked for in case we handle validation ourself */
3758         prs->flags &= ~BIT_CD;
3759
3760         /* normalize and sanitize: easy to delete items from linked lists */
3761         if(!scrub_message(pkt, prs, &iq->qinfo_out, iq->dp->name,
3762                 qstate->env->scratch, qstate->env, ie)) {
3763                 /* if 0x20 enabled, start fallback, but we have no message */
3764                 if(event == module_event_capsfail && !iq->caps_fallback) {
3765                         iq->caps_fallback = 1;
3766                         iq->caps_server = 0;
3767                         iq->caps_reply = NULL;
3768                         iq->caps_response = NULL;
3769                         iq->caps_minimisation_state = DONOT_MINIMISE_STATE;
3770                         iq->state = QUERYTARGETS_STATE;
3771                         iq->num_current_queries--;
3772                         verbose(VERB_DETAIL, "Capsforid: scrub failed, starting fallback with no response");
3773                 }
3774                 goto handle_it;
3775         }
3776
3777         /* allocate response dns_msg in region */
3778         iq->response = dns_alloc_msg(pkt, prs, qstate->region);
3779         if(!iq->response)
3780                 goto handle_it;
3781         log_query_info(VERB_DETAIL, "response for", &qstate->qinfo);
3782         log_name_addr(VERB_DETAIL, "reply from", iq->dp->name,
3783                 &qstate->reply->addr, qstate->reply->addrlen);
3784         if(verbosity >= VERB_ALGO)
3785                 log_dns_msg("incoming scrubbed packet:", &iq->response->qinfo,
3786                         iq->response->rep);
3787
3788         if(event == module_event_capsfail || iq->caps_fallback) {
3789                 if(qstate->env->cfg->qname_minimisation &&
3790                         iq->minimisation_state != DONOT_MINIMISE_STATE) {
3791                         /* Skip QNAME minimisation for next query, since that
3792                          * one has to match the current query. */
3793                         iq->minimisation_state = SKIP_MINIMISE_STATE;
3794                 }
3795                 /* for fallback we care about main answer, not additionals */
3796                 /* removing that makes comparison more likely to succeed */
3797                 caps_strip_reply(iq->response->rep);
3798
3799                 if(iq->caps_fallback &&
3800                         iq->caps_minimisation_state != iq->minimisation_state) {
3801                         /* QNAME minimisation state has changed, restart caps
3802                          * fallback. */
3803                         iq->caps_fallback = 0;
3804                 }
3805
3806                 if(!iq->caps_fallback) {
3807                         /* start fallback */
3808                         iq->caps_fallback = 1;
3809                         iq->caps_server = 0;
3810                         iq->caps_reply = iq->response->rep;
3811                         iq->caps_response = iq->response;
3812                         iq->caps_minimisation_state = iq->minimisation_state;
3813                         iq->state = QUERYTARGETS_STATE;
3814                         iq->num_current_queries--;
3815                         verbose(VERB_DETAIL, "Capsforid: starting fallback");
3816                         goto handle_it;
3817                 } else {
3818                         /* check if reply is the same, otherwise, fail */
3819                         if(!iq->caps_reply) {
3820                                 iq->caps_reply = iq->response->rep;
3821                                 iq->caps_response = iq->response;
3822                                 iq->caps_server = -1; /*become zero at ++,
3823                                 so that we start the full set of trials */
3824                         } else if(caps_failed_rcode(iq->caps_reply) &&
3825                                 !caps_failed_rcode(iq->response->rep)) {
3826                                 /* prefer to upgrade to non-SERVFAIL */
3827                                 iq->caps_reply = iq->response->rep;
3828                                 iq->caps_response = iq->response;
3829                         } else if(!caps_failed_rcode(iq->caps_reply) &&
3830                                 caps_failed_rcode(iq->response->rep)) {
3831                                 /* if we have non-SERVFAIL as answer then
3832                                  * we can ignore SERVFAILs for the equality
3833                                  * comparison */
3834                                 /* no instructions here, skip other else */
3835                         } else if(caps_failed_rcode(iq->caps_reply) &&
3836                                 caps_failed_rcode(iq->response->rep)) {
3837                                 /* failure is same as other failure in fallbk*/
3838                                 /* no instructions here, skip other else */
3839                         } else if(!reply_equal(iq->response->rep, iq->caps_reply,
3840                                 qstate->env->scratch)) {
3841                                 verbose(VERB_DETAIL, "Capsforid fallback: "
3842                                         "getting different replies, failed");
3843                                 outbound_list_remove(&iq->outlist, outbound);
3844                                 errinf(qstate, "0x20 failed, then got different replies in fallback");
3845                                 (void)error_response(qstate, id,
3846                                         LDNS_RCODE_SERVFAIL);
3847                                 return;
3848                         }
3849                         /* continue the fallback procedure at next server */
3850                         iq->caps_server++;
3851                         iq->state = QUERYTARGETS_STATE;
3852                         iq->num_current_queries--;
3853                         verbose(VERB_DETAIL, "Capsforid: reply is equal. "
3854                                 "go to next fallback");
3855                         goto handle_it;
3856                 }
3857         }
3858         iq->caps_fallback = 0; /* if we were in fallback, 0x20 is OK now */
3859
3860 handle_it:
3861         outbound_list_remove(&iq->outlist, outbound);
3862         iter_handle(qstate, iq, ie, id);
3863 }
3864
3865 void
3866 iter_operate(struct module_qstate* qstate, enum module_ev event, int id,
3867         struct outbound_entry* outbound)
3868 {
3869         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
3870         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3871         verbose(VERB_QUERY, "iterator[module %d] operate: extstate:%s event:%s",
3872                 id, strextstate(qstate->ext_state[id]), strmodulevent(event));
3873         if(iq) log_query_info(VERB_QUERY, "iterator operate: query",
3874                 &qstate->qinfo);
3875         if(iq && qstate->qinfo.qname != iq->qchase.qname)
3876                 log_query_info(VERB_QUERY, "iterator operate: chased to",
3877                         &iq->qchase);
3878
3879         /* perform iterator state machine */
3880         if((event == module_event_new || event == module_event_pass) &&
3881                 iq == NULL) {
3882                 if(!iter_new(qstate, id)) {
3883                         errinf(qstate, "malloc failure, new iterator module allocation");
3884                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3885                         return;
3886                 }
3887                 iq = (struct iter_qstate*)qstate->minfo[id];
3888                 process_request(qstate, iq, ie, id);
3889                 return;
3890         }
3891         if(iq && event == module_event_pass) {
3892                 iter_handle(qstate, iq, ie, id);
3893                 return;
3894         }
3895         if(iq && outbound) {
3896                 process_response(qstate, iq, ie, id, outbound, event);
3897                 return;
3898         }
3899         if(event == module_event_error) {
3900                 verbose(VERB_ALGO, "got called with event error, giving up");
3901                 errinf(qstate, "iterator module got the error event");
3902                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3903                 return;
3904         }
3905
3906         log_err("bad event for iterator");
3907         errinf(qstate, "iterator module received wrong event");
3908         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3909 }
3910
3911 void
3912 iter_clear(struct module_qstate* qstate, int id)
3913 {
3914         struct iter_qstate* iq;
3915         if(!qstate)
3916                 return;
3917         iq = (struct iter_qstate*)qstate->minfo[id];
3918         if(iq) {
3919                 outbound_list_clear(&iq->outlist);
3920                 if(iq->target_count && --iq->target_count[0] == 0)
3921                         free(iq->target_count);
3922                 iq->num_current_queries = 0;
3923         }
3924         qstate->minfo[id] = NULL;
3925 }
3926
3927 size_t
3928 iter_get_mem(struct module_env* env, int id)
3929 {
3930         struct iter_env* ie = (struct iter_env*)env->modinfo[id];
3931         if(!ie)
3932                 return 0;
3933         return sizeof(*ie) + sizeof(int)*((size_t)ie->max_dependency_depth+1)
3934                 + donotq_get_mem(ie->donotq) + priv_get_mem(ie->priv);
3935 }
3936
3937 /**
3938  * The iterator function block
3939  */
3940 static struct module_func_block iter_block = {
3941         "iterator",
3942         &iter_init, &iter_deinit, &iter_operate, &iter_inform_super,
3943         &iter_clear, &iter_get_mem
3944 };
3945
3946 struct module_func_block*
3947 iter_get_funcblock(void)
3948 {
3949         return &iter_block;
3950 }
3951
3952 const char*
3953 iter_state_to_string(enum iter_state state)
3954 {
3955         switch (state)
3956         {
3957         case INIT_REQUEST_STATE :
3958                 return "INIT REQUEST STATE";
3959         case INIT_REQUEST_2_STATE :
3960                 return "INIT REQUEST STATE (stage 2)";
3961         case INIT_REQUEST_3_STATE:
3962                 return "INIT REQUEST STATE (stage 3)";
3963         case QUERYTARGETS_STATE :
3964                 return "QUERY TARGETS STATE";
3965         case PRIME_RESP_STATE :
3966                 return "PRIME RESPONSE STATE";
3967         case COLLECT_CLASS_STATE :
3968                 return "COLLECT CLASS STATE";
3969         case DSNS_FIND_STATE :
3970                 return "DSNS FIND STATE";
3971         case QUERY_RESP_STATE :
3972                 return "QUERY RESPONSE STATE";
3973         case FINISHED_STATE :
3974                 return "FINISHED RESPONSE STATE";
3975         default :
3976                 return "UNKNOWN ITER STATE";
3977         }
3978 }
3979
3980 int
3981 iter_state_is_responsestate(enum iter_state s)
3982 {
3983         switch(s) {
3984                 case INIT_REQUEST_STATE :
3985                 case INIT_REQUEST_2_STATE :
3986                 case INIT_REQUEST_3_STATE :
3987                 case QUERYTARGETS_STATE :
3988                 case COLLECT_CLASS_STATE :
3989                         return 0;
3990                 default:
3991                         break;
3992         }
3993         return 1;
3994 }