iterator/iterator.c

   1 /*
   2  * iterator/iterator.c - iterative resolver DNS query response module
   3  *
   4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
   5  *
   6  * This software is open source.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * Redistributions of source code must retain the above copyright notice,
  13  * this list of conditions and the following disclaimer.
  14  *
  15  * Redistributions in binary form must reproduce the above copyright notice,
  16  * this list of conditions and the following disclaimer in the documentation
  17  * and/or other materials provided with the distribution.
  18  *
  19  * Neither the name of the NLNET LABS nor the names of its contributors may
  20  * be used to endorse or promote products derived from this software without
  21  * specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 /**
  37  * \file
  38  *
  39  * This file contains a module that performs recusive iterative DNS query
  40  * processing.
  41  */
  42
  43 #include "config.h"
  44 #include "iterator/iterator.h"
  45 #include "iterator/iter_utils.h"
  46 #include "iterator/iter_hints.h"
  47 #include "iterator/iter_fwd.h"
  48 #include "iterator/iter_donotq.h"
  49 #include "iterator/iter_delegpt.h"
  50 #include "iterator/iter_resptype.h"
  51 #include "iterator/iter_scrub.h"
  52 #include "iterator/iter_priv.h"
  53 #include "validator/val_neg.h"
  54 #include "services/cache/dns.h"
  55 #include "services/cache/infra.h"
  56 #include "util/module.h"
  57 #include "util/netevent.h"
  58 #include "util/net_help.h"
  59 #include "util/regional.h"
  60 #include "util/data/dname.h"
  61 #include "util/data/msgencode.h"
  62 #include "util/fptr_wlist.h"
  63 #include "util/config_file.h"
  64 #include "util/random.h"
  65 #include "sldns/rrdef.h"
  66 #include "sldns/wire2str.h"
  67 #include "sldns/str2wire.h"
  68 #include "sldns/parseutil.h"
  69 #include "sldns/sbuffer.h"
  70
  71 int
  72 iter_init(struct module_env* env, int id)
  73 {
  74         struct iter_env* iter_env = (struct iter_env*)calloc(1,
  75                 sizeof(struct iter_env));
  76         if(!iter_env) {
  77                 log_err("malloc failure");
  78                 return 0;
  79         }
  80         env->modinfo[id] = (void*)iter_env;
  81         if(!iter_apply_cfg(iter_env, env->cfg)) {
  82                 log_err("iterator: could not apply configuration settings.");
  83                 return 0;
  84         }
  85
  86         return 1;
  87 }
  88
  89 /** delete caps_whitelist element */
  90 static void
  91 caps_free(struct rbnode_type* n, void* ATTR_UNUSED(d))
  92 {
  93         if(n) {
  94                 free(((struct name_tree_node*)n)->name);
  95                 free(n);
  96         }
  97 }
  98
  99 void
 100 iter_deinit(struct module_env* env, int id)
 101 {
 102         struct iter_env* iter_env;
 103         if(!env || !env->modinfo[id])
 104                 return;
 105         iter_env = (struct iter_env*)env->modinfo[id];
 106         free(iter_env->target_fetch_policy);
 107         priv_delete(iter_env->priv);
 108         donotq_delete(iter_env->donotq);
 109         if(iter_env->caps_white) {
 110                 traverse_postorder(iter_env->caps_white, caps_free, NULL);
 111                 free(iter_env->caps_white);
 112         }
 113         free(iter_env);
 114         env->modinfo[id] = NULL;
 115 }
 116
 117 /** new query for iterator */
 118 static int
 119 iter_new(struct module_qstate* qstate, int id)
 120 {
 121         struct iter_qstate* iq = (struct iter_qstate*)regional_alloc(
 122                 qstate->region, sizeof(struct iter_qstate));
 123         qstate->minfo[id] = iq;
 124         if(!iq)
 125                 return 0;
 126         memset(iq, 0, sizeof(*iq));
 127         iq->state = INIT_REQUEST_STATE;
 128         iq->final_state = FINISHED_STATE;
 129         iq->an_prepend_list = NULL;
 130         iq->an_prepend_last = NULL;
 131         iq->ns_prepend_list = NULL;
 132         iq->ns_prepend_last = NULL;
 133         iq->dp = NULL;
 134         iq->depth = 0;
 135         iq->num_target_queries = 0;
 136         iq->num_current_queries = 0;
 137         iq->query_restart_count = 0;
 138         iq->referral_count = 0;
 139         iq->sent_count = 0;
 140         iq->ratelimit_ok = 0;
 141         iq->target_count = NULL;
 142         iq->wait_priming_stub = 0;
 143         iq->refetch_glue = 0;
 144         iq->dnssec_expected = 0;
 145         iq->dnssec_lame_query = 0;
 146         iq->chase_flags = qstate->query_flags;
 147         /* Start with the (current) qname. */
 148         iq->qchase = qstate->qinfo;
 149         outbound_list_init(&iq->outlist);
 150         iq->minimise_count = 0;
 151         iq->minimise_timeout_count = 0;
 152         if (qstate->env->cfg->qname_minimisation)
 153                 iq->minimisation_state = INIT_MINIMISE_STATE;
 154         else
 155                 iq->minimisation_state = DONOT_MINIMISE_STATE;
 156
 157         memset(&iq->qinfo_out, 0, sizeof(struct query_info));
 158         return 1;
 159 }
 160
 161 /**
 162  * Transition to the next state. This can be used to advance a currently
 163  * processing event. It cannot be used to reactivate a forEvent.
 164  *
 165  * @param iq: iterator query state
 166  * @param nextstate The state to transition to.
 167  * @return true. This is so this can be called as the return value for the
 168  *         actual process*State() methods. (Transitioning to the next state
 169  *         implies further processing).
 170  */
 171 static int
 172 next_state(struct iter_qstate* iq, enum iter_state nextstate)
 173 {
 174         /* If transitioning to a "response" state, make sure that there is a
 175          * response */
 176         if(iter_state_is_responsestate(nextstate)) {
 177                 if(iq->response == NULL) {
 178                         log_err("transitioning to response state sans "
 179                                 "response.");
 180                 }
 181         }
 182         iq->state = nextstate;
 183         return 1;
 184 }
 185
 186 /**
 187  * Transition an event to its final state. Final states always either return
 188  * a result up the module chain, or reactivate a dependent event. Which
 189  * final state to transition to is set in the module state for the event when
 190  * it was created, and depends on the original purpose of the event.
 191  *
 192  * The response is stored in the qstate->buf buffer.
 193  *
 194  * @param iq: iterator query state
 195  * @return false. This is so this method can be used as the return value for
 196  *         the processState methods. (Transitioning to the final state
 197  */
 198 static int
 199 final_state(struct iter_qstate* iq)
 200 {
 201         return next_state(iq, iq->final_state);
 202 }
 203
 204 /**
 205  * Callback routine to handle errors in parent query states
 206  * @param qstate: query state that failed.
 207  * @param id: module id.
 208  * @param super: super state.
 209  */
 210 static void
 211 error_supers(struct module_qstate* qstate, int id, struct module_qstate* super)
 212 {
 213         struct iter_qstate* super_iq = (struct iter_qstate*)super->minfo[id];
 214
 215         if(qstate->qinfo.qtype == LDNS_RR_TYPE_A ||
 216                 qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA) {
 217                 /* mark address as failed. */
 218                 struct delegpt_ns* dpns = NULL;
 219                 super_iq->num_target_queries--;
 220                 if(super_iq->dp)
 221                         dpns = delegpt_find_ns(super_iq->dp,
 222                                 qstate->qinfo.qname, qstate->qinfo.qname_len);
 223                 if(!dpns) {
 224                         /* not interested */
 225                         verbose(VERB_ALGO, "subq error, but not interested");
 226                         log_query_info(VERB_ALGO, "superq", &super->qinfo);
 227                         if(super_iq->dp)
 228                                 delegpt_log(VERB_ALGO, super_iq->dp);
 229                         log_assert(0);
 230                         return;
 231                 } else {
 232                         /* see if the failure did get (parent-lame) info */
 233                         if(!cache_fill_missing(super->env, super_iq->qchase.qclass,
 234                                 super->region, super_iq->dp))
 235                                 log_err("out of memory adding missing");
 236                 }
 237                 dpns->resolved = 1; /* mark as failed */
 238         }
 239         if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS) {
 240                 /* prime failed to get delegation */
 241                 super_iq->dp = NULL;
 242         }
 243         /* evaluate targets again */
 244         super_iq->state = QUERYTARGETS_STATE;
 245         /* super becomes runnable, and will process this change */
 246 }
 247
 248 /**
 249  * Return an error to the client
 250  * @param qstate: our query state
 251  * @param id: module id
 252  * @param rcode: error code (DNS errcode).
 253  * @return: 0 for use by caller, to make notation easy, like:
 254  *      return error_response(..).
 255  */
 256 static int
 257 error_response(struct module_qstate* qstate, int id, int rcode)
 258 {
 259         verbose(VERB_QUERY, "return error response %s",
 260                 sldns_lookup_by_id(sldns_rcodes, rcode)?
 261                 sldns_lookup_by_id(sldns_rcodes, rcode)->name:"??");
 262         qstate->return_rcode = rcode;
 263         qstate->return_msg = NULL;
 264         qstate->ext_state[id] = module_finished;
 265         return 0;
 266 }
 267
 268 /**
 269  * Return an error to the client and cache the error code in the
 270  * message cache (so per qname, qtype, qclass).
 271  * @param qstate: our query state
 272  * @param id: module id
 273  * @param rcode: error code (DNS errcode).
 274  * @return: 0 for use by caller, to make notation easy, like:
 275  *      return error_response(..).
 276  */
 277 static int
 278 error_response_cache(struct module_qstate* qstate, int id, int rcode)
 279 {
 280         if(!qstate->no_cache_store) {
 281                 /* store in cache */
 282                 struct reply_info err;
 283                 if(qstate->prefetch_leeway > NORR_TTL) {
 284                         verbose(VERB_ALGO, "error response for prefetch in cache");
 285                         /* attempt to adjust the cache entry prefetch */
 286                         if(dns_cache_prefetch_adjust(qstate->env, &qstate->qinfo,
 287                                 NORR_TTL, qstate->query_flags))
 288                                 return error_response(qstate, id, rcode);
 289                         /* if that fails (not in cache), fall through to store err */
 290                 }
 291                 memset(&err, 0, sizeof(err));
 292                 err.flags = (uint16_t)(BIT_QR | BIT_RA);
 293                 FLAGS_SET_RCODE(err.flags, rcode);
 294                 err.qdcount = 1;
 295                 err.ttl = NORR_TTL;
 296                 err.prefetch_ttl = PREFETCH_TTL_CALC(err.ttl);
 297                 /* do not waste time trying to validate this servfail */
 298                 err.security = sec_status_indeterminate;
 299                 verbose(VERB_ALGO, "store error response in message cache");
 300                 iter_dns_store(qstate->env, &qstate->qinfo, &err, 0, 0, 0, NULL,
 301                         qstate->query_flags);
 302         }
 303         return error_response(qstate, id, rcode);
 304 }
 305
 306 /** check if prepend item is duplicate item */
 307 static int
 308 prepend_is_duplicate(struct ub_packed_rrset_key** sets, size_t to,
 309         struct ub_packed_rrset_key* dup)
 310 {
 311         size_t i;
 312         for(i=0; i<to; i++) {
 313                 if(sets[i]->rk.type == dup->rk.type &&
 314                         sets[i]->rk.rrset_class == dup->rk.rrset_class &&
 315                         sets[i]->rk.dname_len == dup->rk.dname_len &&
 316                         query_dname_compare(sets[i]->rk.dname, dup->rk.dname)
 317                         == 0)
 318                         return 1;
 319         }
 320         return 0;
 321 }
 322
 323 /** prepend the prepend list in the answer and authority section of dns_msg */
 324 static int
 325 iter_prepend(struct iter_qstate* iq, struct dns_msg* msg,
 326         struct regional* region)
 327 {
 328         struct iter_prep_list* p;
 329         struct ub_packed_rrset_key** sets;
 330         size_t num_an = 0, num_ns = 0;;
 331         for(p = iq->an_prepend_list; p; p = p->next)
 332                 num_an++;
 333         for(p = iq->ns_prepend_list; p; p = p->next)
 334                 num_ns++;
 335         if(num_an + num_ns == 0)
 336                 return 1;
 337         verbose(VERB_ALGO, "prepending %d rrsets", (int)num_an + (int)num_ns);
 338         if(num_an > RR_COUNT_MAX || num_ns > RR_COUNT_MAX ||
 339                 msg->rep->rrset_count > RR_COUNT_MAX) return 0; /* overflow */
 340         sets = regional_alloc(region, (num_an+num_ns+msg->rep->rrset_count) *
 341                 sizeof(struct ub_packed_rrset_key*));
 342         if(!sets)
 343                 return 0;
 344         /* ANSWER section */
 345         num_an = 0;
 346         for(p = iq->an_prepend_list; p; p = p->next) {
 347                 sets[num_an++] = p->rrset;
 348         }
 349         memcpy(sets+num_an, msg->rep->rrsets, msg->rep->an_numrrsets *
 350                 sizeof(struct ub_packed_rrset_key*));
 351         /* AUTH section */
 352         num_ns = 0;
 353         for(p = iq->ns_prepend_list; p; p = p->next) {
 354                 if(prepend_is_duplicate(sets+msg->rep->an_numrrsets+num_an,
 355                         num_ns, p->rrset) || prepend_is_duplicate(
 356                         msg->rep->rrsets+msg->rep->an_numrrsets,
 357                         msg->rep->ns_numrrsets, p->rrset))
 358                         continue;
 359                 sets[msg->rep->an_numrrsets + num_an + num_ns++] = p->rrset;
 360         }
 361         memcpy(sets + num_an + msg->rep->an_numrrsets + num_ns,
 362                 msg->rep->rrsets + msg->rep->an_numrrsets,
 363                 (msg->rep->ns_numrrsets + msg->rep->ar_numrrsets) *
 364                 sizeof(struct ub_packed_rrset_key*));
 365
 366         /* NXDOMAIN rcode can stay if we prepended DNAME/CNAMEs, because
 367          * this is what recursors should give. */
 368         msg->rep->rrset_count += num_an + num_ns;
 369         msg->rep->an_numrrsets += num_an;
 370         msg->rep->ns_numrrsets += num_ns;
 371         msg->rep->rrsets = sets;
 372         return 1;
 373 }
 374
 375 /**
 376  * Find rrset in ANSWER prepend list.
 377  * to avoid duplicate DNAMEs when a DNAME is traversed twice.
 378  * @param iq: iterator query state.
 379  * @param rrset: rrset to add.
 380  * @return false if not found
 381  */
 382 static int
 383 iter_find_rrset_in_prepend_answer(struct iter_qstate* iq,
 384         struct ub_packed_rrset_key* rrset)
 385 {
 386         struct iter_prep_list* p = iq->an_prepend_list;
 387         while(p) {
 388                 if(ub_rrset_compare(p->rrset, rrset) == 0 &&
 389                         rrsetdata_equal((struct packed_rrset_data*)p->rrset
 390                         ->entry.data, (struct packed_rrset_data*)rrset
 391                         ->entry.data))
 392                         return 1;
 393                 p = p->next;
 394         }
 395         return 0;
 396 }
 397
 398 /**
 399  * Add rrset to ANSWER prepend list
 400  * @param qstate: query state.
 401  * @param iq: iterator query state.
 402  * @param rrset: rrset to add.
 403  * @return false on failure (malloc).
 404  */
 405 static int
 406 iter_add_prepend_answer(struct module_qstate* qstate, struct iter_qstate* iq,
 407         struct ub_packed_rrset_key* rrset)
 408 {
 409         struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc(
 410                 qstate->region, sizeof(struct iter_prep_list));
 411         if(!p)
 412                 return 0;
 413         p->rrset = rrset;
 414         p->next = NULL;
 415         /* add at end */
 416         if(iq->an_prepend_last)
 417                 iq->an_prepend_last->next = p;
 418         else    iq->an_prepend_list = p;
 419         iq->an_prepend_last = p;
 420         return 1;
 421 }
 422
 423 /**
 424  * Add rrset to AUTHORITY prepend list
 425  * @param qstate: query state.
 426  * @param iq: iterator query state.
 427  * @param rrset: rrset to add.
 428  * @return false on failure (malloc).
 429  */
 430 static int
 431 iter_add_prepend_auth(struct module_qstate* qstate, struct iter_qstate* iq,
 432         struct ub_packed_rrset_key* rrset)
 433 {
 434         struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc(
 435                 qstate->region, sizeof(struct iter_prep_list));
 436         if(!p)
 437                 return 0;
 438         p->rrset = rrset;
 439         p->next = NULL;
 440         /* add at end */
 441         if(iq->ns_prepend_last)
 442                 iq->ns_prepend_last->next = p;
 443         else    iq->ns_prepend_list = p;
 444         iq->ns_prepend_last = p;
 445         return 1;
 446 }
 447
 448 /**
 449  * Given a CNAME response (defined as a response containing a CNAME or DNAME
 450  * that does not answer the request), process the response, modifying the
 451  * state as necessary. This follows the CNAME/DNAME chain and returns the
 452  * final query name.
 453  *
 454  * sets the new query name, after following the CNAME/DNAME chain.
 455  * @param qstate: query state.
 456  * @param iq: iterator query state.
 457  * @param msg: the response.
 458  * @param mname: returned target new query name.
 459  * @param mname_len: length of mname.
 460  * @return false on (malloc) error.
 461  */
 462 static int
 463 handle_cname_response(struct module_qstate* qstate, struct iter_qstate* iq,
 464         struct dns_msg* msg, uint8_t** mname, size_t* mname_len)
 465 {
 466         size_t i;
 467         /* Start with the (current) qname. */
 468         *mname = iq->qchase.qname;
 469         *mname_len = iq->qchase.qname_len;
 470
 471         /* Iterate over the ANSWER rrsets in order, looking for CNAMEs and
 472          * DNAMES. */
 473         for(i=0; i<msg->rep->an_numrrsets; i++) {
 474                 struct ub_packed_rrset_key* r = msg->rep->rrsets[i];
 475                 /* If there is a (relevant) DNAME, add it to the list.
 476                  * We always expect there to be CNAME that was generated
 477                  * by this DNAME following, so we don't process the DNAME
 478                  * directly.  */
 479                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_DNAME &&
 480                         dname_strict_subdomain_c(*mname, r->rk.dname) &&
 481                         !iter_find_rrset_in_prepend_answer(iq, r)) {
 482                         if(!iter_add_prepend_answer(qstate, iq, r))
 483                                 return 0;
 484                         continue;
 485                 }
 486
 487                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_CNAME &&
 488                         query_dname_compare(*mname, r->rk.dname) == 0 &&
 489                         !iter_find_rrset_in_prepend_answer(iq, r)) {
 490                         /* Add this relevant CNAME rrset to the prepend list.*/
 491                         if(!iter_add_prepend_answer(qstate, iq, r))
 492                                 return 0;
 493                         get_cname_target(r, mname, mname_len);
 494                 }
 495
 496                 /* Other rrsets in the section are ignored. */
 497         }
 498         /* add authority rrsets to authority prepend, for wildcarded CNAMEs */
 499         for(i=msg->rep->an_numrrsets; i<msg->rep->an_numrrsets +
 500                 msg->rep->ns_numrrsets; i++) {
 501                 struct ub_packed_rrset_key* r = msg->rep->rrsets[i];
 502                 /* only add NSEC/NSEC3, as they may be needed for validation */
 503                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC ||
 504                         ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC3) {
 505                         if(!iter_add_prepend_auth(qstate, iq, r))
 506                                 return 0;
 507                 }
 508         }
 509         return 1;
 510 }
 511
 512 /** see if target name is caps-for-id whitelisted */
 513 static int
 514 is_caps_whitelisted(struct iter_env* ie, struct iter_qstate* iq)
 515 {
 516         if(!ie->caps_white) return 0; /* no whitelist, or no capsforid */
 517         return name_tree_lookup(ie->caps_white, iq->qchase.qname,
 518                 iq->qchase.qname_len, dname_count_labels(iq->qchase.qname),
 519                 iq->qchase.qclass) != NULL;
 520 }
 521
 522 /** create target count structure for this query */
 523 static void
 524 target_count_create(struct iter_qstate* iq)
 525 {
 526         if(!iq->target_count) {
 527                 iq->target_count = (int*)calloc(2, sizeof(int));
 528                 /* if calloc fails we simply do not track this number */
 529                 if(iq->target_count)
 530                         iq->target_count[0] = 1;
 531         }
 532 }
 533
 534 static void
 535 target_count_increase(struct iter_qstate* iq, int num)
 536 {
 537         target_count_create(iq);
 538         if(iq->target_count)
 539                 iq->target_count[1] += num;
 540 }
 541
 542 /**
 543  * Generate a subrequest.
 544  * Generate a local request event. Local events are tied to this module, and
 545  * have a corresponding (first tier) event that is waiting for this event to
 546  * resolve to continue.
 547  *
 548  * @param qname The query name for this request.
 549  * @param qnamelen length of qname
 550  * @param qtype The query type for this request.
 551  * @param qclass The query class for this request.
 552  * @param qstate The event that is generating this event.
 553  * @param id: module id.
 554  * @param iq: The iterator state that is generating this event.
 555  * @param initial_state The initial response state (normally this
 556  *          is QUERY_RESP_STATE, unless it is known that the request won't
 557  *          need iterative processing
 558  * @param finalstate The final state for the response to this request.
 559  * @param subq_ret: if newly allocated, the subquerystate, or NULL if it does
 560  *      not need initialisation.
 561  * @param v: if true, validation is done on the subquery.
 562  * @return false on error (malloc).
 563  */
 564 static int
 565 generate_sub_request(uint8_t* qname, size_t qnamelen, uint16_t qtype,
 566         uint16_t qclass, struct module_qstate* qstate, int id,
 567         struct iter_qstate* iq, enum iter_state initial_state,
 568         enum iter_state finalstate, struct module_qstate** subq_ret, int v)
 569 {
 570         struct module_qstate* subq = NULL;
 571         struct iter_qstate* subiq = NULL;
 572         uint16_t qflags = 0; /* OPCODE QUERY, no flags */
 573         struct query_info qinf;
 574         int prime = (finalstate == PRIME_RESP_STATE)?1:0;
 575         int valrec = 0;
 576         qinf.qname = qname;
 577         qinf.qname_len = qnamelen;
 578         qinf.qtype = qtype;
 579         qinf.qclass = qclass;
 580         qinf.local_alias = NULL;
 581
 582         /* RD should be set only when sending the query back through the INIT
 583          * state. */
 584         if(initial_state == INIT_REQUEST_STATE)
 585                 qflags |= BIT_RD;
 586         /* We set the CD flag so we can send this through the "head" of
 587          * the resolution chain, which might have a validator. We are
 588          * uninterested in validating things not on the direct resolution
 589          * path.  */
 590         if(!v) {
 591                 qflags |= BIT_CD;
 592                 valrec = 1;
 593         }
 594
 595         /* attach subquery, lookup existing or make a new one */
 596         fptr_ok(fptr_whitelist_modenv_attach_sub(qstate->env->attach_sub));
 597         if(!(*qstate->env->attach_sub)(qstate, &qinf, qflags, prime, valrec,
 598                 &subq)) {
 599                 return 0;
 600         }
 601         *subq_ret = subq;
 602         if(subq) {
 603                 /* initialise the new subquery */
 604                 subq->curmod = id;
 605                 subq->ext_state[id] = module_state_initial;
 606                 subq->minfo[id] = regional_alloc(subq->region,
 607                         sizeof(struct iter_qstate));
 608                 if(!subq->minfo[id]) {
 609                         log_err("init subq: out of memory");
 610                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 611                                 qstate->env->kill_sub));
 612                         (*qstate->env->kill_sub)(subq);
 613                         return 0;
 614                 }
 615                 subiq = (struct iter_qstate*)subq->minfo[id];
 616                 memset(subiq, 0, sizeof(*subiq));
 617                 subiq->num_target_queries = 0;
 618                 target_count_create(iq);
 619                 subiq->target_count = iq->target_count;
 620                 if(iq->target_count)
 621                         iq->target_count[0] ++; /* extra reference */
 622                 subiq->num_current_queries = 0;
 623                 subiq->depth = iq->depth+1;
 624                 outbound_list_init(&subiq->outlist);
 625                 subiq->state = initial_state;
 626                 subiq->final_state = finalstate;
 627                 subiq->qchase = subq->qinfo;
 628                 subiq->chase_flags = subq->query_flags;
 629                 subiq->refetch_glue = 0;
 630                 if(qstate->env->cfg->qname_minimisation)
 631                         subiq->minimisation_state = INIT_MINIMISE_STATE;
 632                 else
 633                         subiq->minimisation_state = DONOT_MINIMISE_STATE;
 634                 memset(&subiq->qinfo_out, 0, sizeof(struct query_info));
 635         }
 636         return 1;
 637 }
 638
 639 /**
 640  * Generate and send a root priming request.
 641  * @param qstate: the qtstate that triggered the need to prime.
 642  * @param iq: iterator query state.
 643  * @param id: module id.
 644  * @param qclass: the class to prime.
 645  * @return 0 on failure
 646  */
 647 static int
 648 prime_root(struct module_qstate* qstate, struct iter_qstate* iq, int id,
 649         uint16_t qclass)
 650 {
 651         struct delegpt* dp;
 652         struct module_qstate* subq;
 653         verbose(VERB_DETAIL, "priming . %s NS",
 654                 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)?
 655                 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)->name:"??");
 656         dp = hints_lookup_root(qstate->env->hints, qclass);
 657         if(!dp) {
 658                 verbose(VERB_ALGO, "Cannot prime due to lack of hints");
 659                 return 0;
 660         }
 661         /* Priming requests start at the QUERYTARGETS state, skipping
 662          * the normal INIT state logic (which would cause an infloop). */
 663         if(!generate_sub_request((uint8_t*)"\000", 1, LDNS_RR_TYPE_NS,
 664                 qclass, qstate, id, iq, QUERYTARGETS_STATE, PRIME_RESP_STATE,
 665                 &subq, 0)) {
 666                 verbose(VERB_ALGO, "could not prime root");
 667                 return 0;
 668         }
 669         if(subq) {
 670                 struct iter_qstate* subiq =
 671                         (struct iter_qstate*)subq->minfo[id];
 672                 /* Set the initial delegation point to the hint.
 673                  * copy dp, it is now part of the root prime query.
 674                  * dp was part of in the fixed hints structure. */
 675                 subiq->dp = delegpt_copy(dp, subq->region);
 676                 if(!subiq->dp) {
 677                         log_err("out of memory priming root, copydp");
 678                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 679                                 qstate->env->kill_sub));
 680                         (*qstate->env->kill_sub)(subq);
 681                         return 0;
 682                 }
 683                 /* there should not be any target queries. */
 684                 subiq->num_target_queries = 0;
 685                 subiq->dnssec_expected = iter_indicates_dnssec(
 686                         qstate->env, subiq->dp, NULL, subq->qinfo.qclass);
 687         }
 688
 689         /* this module stops, our submodule starts, and does the query. */
 690         qstate->ext_state[id] = module_wait_subquery;
 691         return 1;
 692 }
 693
 694 /**
 695  * Generate and process a stub priming request. This method tests for the
 696  * need to prime a stub zone, so it is safe to call for every request.
 697  *
 698  * @param qstate: the qtstate that triggered the need to prime.
 699  * @param iq: iterator query state.
 700  * @param id: module id.
 701  * @param qname: request name.
 702  * @param qclass: request class.
 703  * @return true if a priming subrequest was made, false if not. The will only
 704  *         issue a priming request if it detects an unprimed stub.
 705  *         Uses value of 2 to signal during stub-prime in root-prime situation
 706  *         that a noprime-stub is available and resolution can continue.
 707  */
 708 static int
 709 prime_stub(struct module_qstate* qstate, struct iter_qstate* iq, int id,
 710         uint8_t* qname, uint16_t qclass)
 711 {
 712         /* Lookup the stub hint. This will return null if the stub doesn't
 713          * need to be re-primed. */
 714         struct iter_hints_stub* stub;
 715         struct delegpt* stub_dp;
 716         struct module_qstate* subq;
 717
 718         if(!qname) return 0;
 719         stub = hints_lookup_stub(qstate->env->hints, qname, qclass, iq->dp);
 720         /* The stub (if there is one) does not need priming. */
 721         if(!stub)
 722                 return 0;
 723         stub_dp = stub->dp;
 724
 725         /* is it a noprime stub (always use) */
 726         if(stub->noprime) {
 727                 int r = 0;
 728                 if(iq->dp == NULL) r = 2;
 729                 /* copy the dp out of the fixed hints structure, so that
 730                  * it can be changed when servicing this query */
 731                 iq->dp = delegpt_copy(stub_dp, qstate->region);
 732                 if(!iq->dp) {
 733                         log_err("out of memory priming stub");
 734                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 735                         return 1; /* return 1 to make module stop, with error */
 736                 }
 737                 log_nametypeclass(VERB_DETAIL, "use stub", stub_dp->name,
 738                         LDNS_RR_TYPE_NS, qclass);
 739                 return r;
 740         }
 741
 742         /* Otherwise, we need to (re)prime the stub. */
 743         log_nametypeclass(VERB_DETAIL, "priming stub", stub_dp->name,
 744                 LDNS_RR_TYPE_NS, qclass);
 745
 746         /* Stub priming events start at the QUERYTARGETS state to avoid the
 747          * redundant INIT state processing. */
 748         if(!generate_sub_request(stub_dp->name, stub_dp->namelen,
 749                 LDNS_RR_TYPE_NS, qclass, qstate, id, iq,
 750                 QUERYTARGETS_STATE, PRIME_RESP_STATE, &subq, 0)) {
 751                 verbose(VERB_ALGO, "could not prime stub");
 752                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 753                 return 1; /* return 1 to make module stop, with error */
 754         }
 755         if(subq) {
 756                 struct iter_qstate* subiq =
 757                         (struct iter_qstate*)subq->minfo[id];
 758
 759                 /* Set the initial delegation point to the hint. */
 760                 /* make copy to avoid use of stub dp by different qs/threads */
 761                 subiq->dp = delegpt_copy(stub_dp, subq->region);
 762                 if(!subiq->dp) {
 763                         log_err("out of memory priming stub, copydp");
 764                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 765                                 qstate->env->kill_sub));
 766                         (*qstate->env->kill_sub)(subq);
 767                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 768                         return 1; /* return 1 to make module stop, with error */
 769                 }
 770                 /* there should not be any target queries -- although there
 771                  * wouldn't be anyway, since stub hints never have
 772                  * missing targets. */
 773                 subiq->num_target_queries = 0;
 774                 subiq->wait_priming_stub = 1;
 775                 subiq->dnssec_expected = iter_indicates_dnssec(
 776                         qstate->env, subiq->dp, NULL, subq->qinfo.qclass);
 777         }
 778
 779         /* this module stops, our submodule starts, and does the query. */
 780         qstate->ext_state[id] = module_wait_subquery;
 781         return 1;
 782 }
 783
 784 /**
 785  * Generate A and AAAA checks for glue that is in-zone for the referral
 786  * we just got to obtain authoritative information on the adresses.
 787  *
 788  * @param qstate: the qtstate that triggered the need to prime.
 789  * @param iq: iterator query state.
 790  * @param id: module id.
 791  */
 792 static void
 793 generate_a_aaaa_check(struct module_qstate* qstate, struct iter_qstate* iq,
 794         int id)
 795 {
 796         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
 797         struct module_qstate* subq;
 798         size_t i;
 799         struct reply_info* rep = iq->response->rep;
 800         struct ub_packed_rrset_key* s;
 801         log_assert(iq->dp);
 802
 803         if(iq->depth == ie->max_dependency_depth)
 804                 return;
 805         /* walk through additional, and check if in-zone,
 806          * only relevant A, AAAA are left after scrub anyway */
 807         for(i=rep->an_numrrsets+rep->ns_numrrsets; i<rep->rrset_count; i++) {
 808                 s = rep->rrsets[i];
 809                 /* check *ALL* addresses that are transmitted in additional*/
 810                 /* is it an address ? */
 811                 if( !(ntohs(s->rk.type)==LDNS_RR_TYPE_A ||
 812                         ntohs(s->rk.type)==LDNS_RR_TYPE_AAAA)) {
 813                         continue;
 814                 }
 815                 /* is this query the same as the A/AAAA check for it */
 816                 if(qstate->qinfo.qtype == ntohs(s->rk.type) &&
 817                         qstate->qinfo.qclass == ntohs(s->rk.rrset_class) &&
 818                         query_dname_compare(qstate->qinfo.qname,
 819                                 s->rk.dname)==0 &&
 820                         (qstate->query_flags&BIT_RD) &&
 821                         !(qstate->query_flags&BIT_CD))
 822                         continue;
 823
 824                 /* generate subrequest for it */
 825                 log_nametypeclass(VERB_ALGO, "schedule addr fetch",
 826                         s->rk.dname, ntohs(s->rk.type),
 827                         ntohs(s->rk.rrset_class));
 828                 if(!generate_sub_request(s->rk.dname, s->rk.dname_len,
 829                         ntohs(s->rk.type), ntohs(s->rk.rrset_class),
 830                         qstate, id, iq,
 831                         INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) {
 832                         verbose(VERB_ALGO, "could not generate addr check");
 833                         return;
 834                 }
 835                 /* ignore subq - not need for more init */
 836         }
 837 }
 838
 839 /**
 840  * Generate a NS check request to obtain authoritative information
 841  * on an NS rrset.
 842  *
 843  * @param qstate: the qtstate that triggered the need to prime.
 844  * @param iq: iterator query state.
 845  * @param id: module id.
 846  */
 847 static void
 848 generate_ns_check(struct module_qstate* qstate, struct iter_qstate* iq, int id)
 849 {
 850         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
 851         struct module_qstate* subq;
 852         log_assert(iq->dp);
 853
 854         if(iq->depth == ie->max_dependency_depth)
 855                 return;
 856         /* is this query the same as the nscheck? */
 857         if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS &&
 858                 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 &&
 859                 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){
 860                 /* spawn off A, AAAA queries for in-zone glue to check */
 861                 generate_a_aaaa_check(qstate, iq, id);
 862                 return;
 863         }
 864
 865         log_nametypeclass(VERB_ALGO, "schedule ns fetch",
 866                 iq->dp->name, LDNS_RR_TYPE_NS, iq->qchase.qclass);
 867         if(!generate_sub_request(iq->dp->name, iq->dp->namelen,
 868                 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
 869                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) {
 870                 verbose(VERB_ALGO, "could not generate ns check");
 871                 return;
 872         }
 873         if(subq) {
 874                 struct iter_qstate* subiq =
 875                         (struct iter_qstate*)subq->minfo[id];
 876
 877                 /* make copy to avoid use of stub dp by different qs/threads */
 878                 /* refetch glue to start higher up the tree */
 879                 subiq->refetch_glue = 1;
 880                 subiq->dp = delegpt_copy(iq->dp, subq->region);
 881                 if(!subiq->dp) {
 882                         log_err("out of memory generating ns check, copydp");
 883                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 884                                 qstate->env->kill_sub));
 885                         (*qstate->env->kill_sub)(subq);
 886                         return;
 887                 }
 888         }
 889 }
 890
 891 /**
 892  * Generate a DNSKEY prefetch query to get the DNSKEY for the DS record we
 893  * just got in a referral (where we have dnssec_expected, thus have trust
 894  * anchors above it).  Note that right after calling this routine the
 895  * iterator detached subqueries (because of following the referral), and thus
 896  * the DNSKEY query becomes detached, its return stored in the cache for
 897  * later lookup by the validator.  This cache lookup by the validator avoids
 898  * the roundtrip incurred by the DNSKEY query.  The DNSKEY query is now
 899  * performed at about the same time the original query is sent to the domain,
 900  * thus the two answers are likely to be returned at about the same time,
 901  * saving a roundtrip from the validated lookup.
 902  *
 903  * @param qstate: the qtstate that triggered the need to prime.
 904  * @param iq: iterator query state.
 905  * @param id: module id.
 906  */
 907 static void
 908 generate_dnskey_prefetch(struct module_qstate* qstate,
 909         struct iter_qstate* iq, int id)
 910 {
 911         struct module_qstate* subq;
 912         log_assert(iq->dp);
 913
 914         /* is this query the same as the prefetch? */
 915         if(qstate->qinfo.qtype == LDNS_RR_TYPE_DNSKEY &&
 916                 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 &&
 917                 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){
 918                 return;
 919         }
 920
 921         /* if the DNSKEY is in the cache this lookup will stop quickly */
 922         log_nametypeclass(VERB_ALGO, "schedule dnskey prefetch",
 923                 iq->dp->name, LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass);
 924         if(!generate_sub_request(iq->dp->name, iq->dp->namelen,
 925                 LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass, qstate, id, iq,
 926                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0)) {
 927                 /* we'll be slower, but it'll work */
 928                 verbose(VERB_ALGO, "could not generate dnskey prefetch");
 929                 return;
 930         }
 931         if(subq) {
 932                 struct iter_qstate* subiq =
 933                         (struct iter_qstate*)subq->minfo[id];
 934                 /* this qstate has the right delegation for the dnskey lookup*/
 935                 /* make copy to avoid use of stub dp by different qs/threads */
 936                 subiq->dp = delegpt_copy(iq->dp, subq->region);
 937                 /* if !subiq->dp, it'll start from the cache, no problem */
 938         }
 939 }
 940
 941 /**
 942  * See if the query needs forwarding.
 943  *
 944  * @param qstate: query state.
 945  * @param iq: iterator query state.
 946  * @return true if the request is forwarded, false if not.
 947  *      If returns true but, iq->dp is NULL then a malloc failure occurred.
 948  */
 949 static int
 950 forward_request(struct module_qstate* qstate, struct iter_qstate* iq)
 951 {
 952         struct delegpt* dp;
 953         uint8_t* delname = iq->qchase.qname;
 954         size_t delnamelen = iq->qchase.qname_len;
 955         if(iq->refetch_glue) {
 956                 delname = iq->dp->name;
 957                 delnamelen = iq->dp->namelen;
 958         }
 959         /* strip one label off of DS query to lookup higher for it */
 960         if( (iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue)
 961                 && !dname_is_root(iq->qchase.qname))
 962                 dname_remove_label(&delname, &delnamelen);
 963         dp = forwards_lookup(qstate->env->fwds, delname, iq->qchase.qclass);
 964         if(!dp)
 965                 return 0;
 966         /* send recursion desired to forward addr */
 967         iq->chase_flags |= BIT_RD;
 968         iq->dp = delegpt_copy(dp, qstate->region);
 969         /* iq->dp checked by caller */
 970         verbose(VERB_ALGO, "forwarding request");
 971         return 1;
 972 }
 973
 974 /**
 975  * Process the initial part of the request handling. This state roughly
 976  * corresponds to resolver algorithms steps 1 (find answer in cache) and 2
 977  * (find the best servers to ask).
 978  *
 979  * Note that all requests start here, and query restarts revisit this state.
 980  *
 981  * This state either generates: 1) a response, from cache or error, 2) a
 982  * priming event, or 3) forwards the request to the next state (init2,
 983  * generally).
 984  *
 985  * @param qstate: query state.
 986  * @param iq: iterator query state.
 987  * @param ie: iterator shared global environment.
 988  * @param id: module id.
 989  * @return true if the event needs more request processing immediately,
 990  *         false if not.
 991  */
 992 static int
 993 processInitRequest(struct module_qstate* qstate, struct iter_qstate* iq,
 994         struct iter_env* ie, int id)
 995 {
 996         uint8_t* delname;
 997         size_t delnamelen;
 998         struct dns_msg* msg = NULL;
 999
1000         log_query_info(VERB_DETAIL, "resolving", &qstate->qinfo);
1001         /* check effort */
1002
1003         /* We enforce a maximum number of query restarts. This is primarily a
1004          * cheap way to prevent CNAME loops. */
1005         if(iq->query_restart_count > MAX_RESTART_COUNT) {
1006                 verbose(VERB_QUERY, "request has exceeded the maximum number"
1007                         " of query restarts with %d", iq->query_restart_count);
1008                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1009         }
1010
1011         /* We enforce a maximum recursion/dependency depth -- in general,
1012          * this is unnecessary for dependency loops (although it will
1013          * catch those), but it provides a sensible limit to the amount
1014          * of work required to answer a given query. */
1015         verbose(VERB_ALGO, "request has dependency depth of %d", iq->depth);
1016         if(iq->depth > ie->max_dependency_depth) {
1017                 verbose(VERB_QUERY, "request has exceeded the maximum "
1018                         "dependency depth with depth of %d", iq->depth);
1019                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1020         }
1021
1022         /* If the request is qclass=ANY, setup to generate each class */
1023         if(qstate->qinfo.qclass == LDNS_RR_CLASS_ANY) {
1024                 iq->qchase.qclass = 0;
1025                 return next_state(iq, COLLECT_CLASS_STATE);
1026         }
1027
1028         /* Resolver Algorithm Step 1 -- Look for the answer in local data. */
1029
1030         /* This either results in a query restart (CNAME cache response), a
1031          * terminating response (ANSWER), or a cache miss (null). */
1032
1033         if(qstate->blacklist) {
1034                 /* if cache, or anything else, was blacklisted then
1035                  * getting older results from cache is a bad idea, no cache */
1036                 verbose(VERB_ALGO, "cache blacklisted, going to the network");
1037                 msg = NULL;
1038         } else if(!qstate->no_cache_lookup) {
1039                 msg = dns_cache_lookup(qstate->env, iq->qchase.qname,
1040                         iq->qchase.qname_len, iq->qchase.qtype,
1041                         iq->qchase.qclass, qstate->query_flags,
1042                         qstate->region, qstate->env->scratch);
1043                 if(!msg && qstate->env->neg_cache) {
1044                         /* lookup in negative cache; may result in
1045                          * NOERROR/NODATA or NXDOMAIN answers that need validation */
1046                         msg = val_neg_getmsg(qstate->env->neg_cache, &iq->qchase,
1047                                 qstate->region, qstate->env->rrset_cache,
1048                                 qstate->env->scratch_buffer,
1049                                 *qstate->env->now, 1/*add SOA*/, NULL);
1050                 }
1051                 /* item taken from cache does not match our query name, thus
1052                  * security needs to be re-examined later */
1053                 if(msg && query_dname_compare(qstate->qinfo.qname,
1054                         iq->qchase.qname) != 0)
1055                         msg->rep->security = sec_status_unchecked;
1056         }
1057         if(msg) {
1058                 /* handle positive cache response */
1059                 enum response_type type = response_type_from_cache(msg,
1060                         &iq->qchase);
1061                 if(verbosity >= VERB_ALGO) {
1062                         log_dns_msg("msg from cache lookup", &msg->qinfo,
1063                                 msg->rep);
1064                         verbose(VERB_ALGO, "msg ttl is %d, prefetch ttl %d",
1065                                 (int)msg->rep->ttl,
1066                                 (int)msg->rep->prefetch_ttl);
1067                 }
1068
1069                 if(type == RESPONSE_TYPE_CNAME) {
1070                         uint8_t* sname = 0;
1071                         size_t slen = 0;
1072                         verbose(VERB_ALGO, "returning CNAME response from "
1073                                 "cache");
1074                         if(!handle_cname_response(qstate, iq, msg,
1075                                 &sname, &slen))
1076                                 return error_response(qstate, id,
1077                                         LDNS_RCODE_SERVFAIL);
1078                         iq->qchase.qname = sname;
1079                         iq->qchase.qname_len = slen;
1080                         /* This *is* a query restart, even if it is a cheap
1081                          * one. */
1082                         iq->dp = NULL;
1083                         iq->refetch_glue = 0;
1084                         iq->query_restart_count++;
1085                         iq->sent_count = 0;
1086                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1087                         if(qstate->env->cfg->qname_minimisation)
1088                                 iq->minimisation_state = INIT_MINIMISE_STATE;
1089                         return next_state(iq, INIT_REQUEST_STATE);
1090                 }
1091
1092                 /* if from cache, NULL, else insert 'cache IP' len=0 */
1093                 if(qstate->reply_origin)
1094                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1095                 /* it is an answer, response, to final state */
1096                 verbose(VERB_ALGO, "returning answer from cache.");
1097                 iq->response = msg;
1098                 return final_state(iq);
1099         }
1100
1101         /* attempt to forward the request */
1102         if(forward_request(qstate, iq))
1103         {
1104                 if(!iq->dp) {
1105                         log_err("alloc failure for forward dp");
1106                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1107                 }
1108                 iq->refetch_glue = 0;
1109                 iq->minimisation_state = DONOT_MINIMISE_STATE;
1110                 /* the request has been forwarded.
1111                  * forwarded requests need to be immediately sent to the
1112                  * next state, QUERYTARGETS. */
1113                 return next_state(iq, QUERYTARGETS_STATE);
1114         }
1115
1116         /* Resolver Algorithm Step 2 -- find the "best" servers. */
1117
1118         /* first, adjust for DS queries. To avoid the grandparent problem,
1119          * we just look for the closest set of server to the parent of qname.
1120          * When re-fetching glue we also need to ask the parent.
1121          */
1122         if(iq->refetch_glue) {
1123                 if(!iq->dp) {
1124                         log_err("internal or malloc fail: no dp for refetch");
1125                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1126                 }
1127                 delname = iq->dp->name;
1128                 delnamelen = iq->dp->namelen;
1129         } else {
1130                 delname = iq->qchase.qname;
1131                 delnamelen = iq->qchase.qname_len;
1132         }
1133         if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue ||
1134            (iq->qchase.qtype == LDNS_RR_TYPE_NS && qstate->prefetch_leeway)) {
1135                 /* remove first label from delname, root goes to hints,
1136                  * but only to fetch glue, not for qtype=DS. */
1137                 /* also when prefetching an NS record, fetch it again from
1138                  * its parent, just as if it expired, so that you do not
1139                  * get stuck on an older nameserver that gives old NSrecords */
1140                 if(dname_is_root(delname) && (iq->refetch_glue ||
1141                         (iq->qchase.qtype == LDNS_RR_TYPE_NS &&
1142                         qstate->prefetch_leeway)))
1143                         delname = NULL; /* go to root priming */
1144                 else    dname_remove_label(&delname, &delnamelen);
1145         }
1146         /* delname is the name to lookup a delegation for. If NULL rootprime */
1147         while(1) {
1148
1149                 /* Lookup the delegation in the cache. If null, then the
1150                  * cache needs to be primed for the qclass. */
1151                 if(delname)
1152                      iq->dp = dns_cache_find_delegation(qstate->env, delname,
1153                         delnamelen, iq->qchase.qtype, iq->qchase.qclass,
1154                         qstate->region, &iq->deleg_msg,
1155                         *qstate->env->now+qstate->prefetch_leeway);
1156                 else iq->dp = NULL;
1157
1158                 /* If the cache has returned nothing, then we have a
1159                  * root priming situation. */
1160                 if(iq->dp == NULL) {
1161                         /* if there is a stub, then no root prime needed */
1162                         int r = prime_stub(qstate, iq, id, delname,
1163                                 iq->qchase.qclass);
1164                         if(r == 2)
1165                                 break; /* got noprime-stub-zone, continue */
1166                         else if(r)
1167                                 return 0; /* stub prime request made */
1168                         if(forwards_lookup_root(qstate->env->fwds,
1169                                 iq->qchase.qclass)) {
1170                                 /* forward zone root, no root prime needed */
1171                                 /* fill in some dp - safety belt */
1172                                 iq->dp = hints_lookup_root(qstate->env->hints,
1173                                         iq->qchase.qclass);
1174                                 if(!iq->dp) {
1175                                         log_err("internal error: no hints dp");
1176                                         return error_response(qstate, id,
1177                                                 LDNS_RCODE_SERVFAIL);
1178                                 }
1179                                 iq->dp = delegpt_copy(iq->dp, qstate->region);
1180                                 if(!iq->dp) {
1181                                         log_err("out of memory in safety belt");
1182                                         return error_response(qstate, id,
1183                                                 LDNS_RCODE_SERVFAIL);
1184                                 }
1185                                 return next_state(iq, INIT_REQUEST_2_STATE);
1186                         }
1187                         /* Note that the result of this will set a new
1188                          * DelegationPoint based on the result of priming. */
1189                         if(!prime_root(qstate, iq, id, iq->qchase.qclass))
1190                                 return error_response(qstate, id,
1191                                         LDNS_RCODE_REFUSED);
1192
1193                         /* priming creates and sends a subordinate query, with
1194                          * this query as the parent. So further processing for
1195                          * this event will stop until reactivated by the
1196                          * results of priming. */
1197                         return 0;
1198                 }
1199                 if(!iq->ratelimit_ok && qstate->prefetch_leeway)
1200                         iq->ratelimit_ok = 1; /* allow prefetches, this keeps
1201                         otherwise valid data in the cache */
1202                 if(!iq->ratelimit_ok && infra_ratelimit_exceeded(
1203                         qstate->env->infra_cache, iq->dp->name,
1204                         iq->dp->namelen, *qstate->env->now)) {
1205                         /* and increment the rate, so that the rate for time
1206                          * now will also exceed the rate, keeping cache fresh */
1207                         (void)infra_ratelimit_inc(qstate->env->infra_cache,
1208                                 iq->dp->name, iq->dp->namelen,
1209                                 *qstate->env->now);
1210                         /* see if we are passed through with slip factor */
1211                         if(qstate->env->cfg->ratelimit_factor != 0 &&
1212                                 ub_random_max(qstate->env->rnd,
1213                                     qstate->env->cfg->ratelimit_factor) == 1) {
1214                                 iq->ratelimit_ok = 1;
1215                                 log_nametypeclass(VERB_ALGO, "ratelimit allowed through for "
1216                                         "delegation point", iq->dp->name,
1217                                         LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
1218                         } else {
1219                                 log_nametypeclass(VERB_ALGO, "ratelimit exceeded with "
1220                                         "delegation point", iq->dp->name,
1221                                         LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
1222                                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1223                         }
1224                 }
1225
1226                 /* see if this dp not useless.
1227                  * It is useless if:
1228                  *      o all NS items are required glue.
1229                  *        or the query is for NS item that is required glue.
1230                  *      o no addresses are provided.
1231                  *      o RD qflag is on.
1232                  * Instead, go up one level, and try to get even further
1233                  * If the root was useless, use safety belt information.
1234                  * Only check cache returns, because replies for servers
1235                  * could be useless but lead to loops (bumping into the
1236                  * same server reply) if useless-checked.
1237                  */
1238                 if(iter_dp_is_useless(&qstate->qinfo, qstate->query_flags,
1239                         iq->dp)) {
1240                         if(dname_is_root(iq->dp->name)) {
1241                                 /* use safety belt */
1242                                 verbose(VERB_QUERY, "Cache has root NS but "
1243                                 "no addresses. Fallback to the safety belt.");
1244                                 iq->dp = hints_lookup_root(qstate->env->hints,
1245                                         iq->qchase.qclass);
1246                                 /* note deleg_msg is from previous lookup,
1247                                  * but RD is on, so it is not used */
1248                                 if(!iq->dp) {
1249                                         log_err("internal error: no hints dp");
1250                                         return error_response(qstate, id,
1251                                                 LDNS_RCODE_REFUSED);
1252                                 }
1253                                 iq->dp = delegpt_copy(iq->dp, qstate->region);
1254                                 if(!iq->dp) {
1255                                         log_err("out of memory in safety belt");
1256                                         return error_response(qstate, id,
1257                                                 LDNS_RCODE_SERVFAIL);
1258                                 }
1259                                 break;
1260                         } else {
1261                                 verbose(VERB_ALGO,
1262                                         "cache delegation was useless:");
1263                                 delegpt_log(VERB_ALGO, iq->dp);
1264                                 /* go up */
1265                                 delname = iq->dp->name;
1266                                 delnamelen = iq->dp->namelen;
1267                                 dname_remove_label(&delname, &delnamelen);
1268                         }
1269                 } else break;
1270         }
1271
1272         verbose(VERB_ALGO, "cache delegation returns delegpt");
1273         delegpt_log(VERB_ALGO, iq->dp);
1274
1275         /* Otherwise, set the current delegation point and move on to the
1276          * next state. */
1277         return next_state(iq, INIT_REQUEST_2_STATE);
1278 }
1279
1280 /**
1281  * Process the second part of the initial request handling. This state
1282  * basically exists so that queries that generate root priming events have
1283  * the same init processing as ones that do not. Request events that reach
1284  * this state must have a valid currentDelegationPoint set.
1285  *
1286  * This part is primarly handling stub zone priming. Events that reach this
1287  * state must have a current delegation point.
1288  *
1289  * @param qstate: query state.
1290  * @param iq: iterator query state.
1291  * @param id: module id.
1292  * @return true if the event needs more request processing immediately,
1293  *         false if not.
1294  */
1295 static int
1296 processInitRequest2(struct module_qstate* qstate, struct iter_qstate* iq,
1297         int id)
1298 {
1299         uint8_t* delname;
1300         size_t delnamelen;
1301         log_query_info(VERB_QUERY, "resolving (init part 2): ",
1302                 &qstate->qinfo);
1303
1304         if(iq->refetch_glue) {
1305                 if(!iq->dp) {
1306                         log_err("internal or malloc fail: no dp for refetch");
1307                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1308                 }
1309                 delname = iq->dp->name;
1310                 delnamelen = iq->dp->namelen;
1311         } else {
1312                 delname = iq->qchase.qname;
1313                 delnamelen = iq->qchase.qname_len;
1314         }
1315         if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue) {
1316                 if(!dname_is_root(delname))
1317                         dname_remove_label(&delname, &delnamelen);
1318                 iq->refetch_glue = 0; /* if CNAME causes restart, no refetch */
1319         }
1320         /* Check to see if we need to prime a stub zone. */
1321         if(prime_stub(qstate, iq, id, delname, iq->qchase.qclass)) {
1322                 /* A priming sub request was made */
1323                 return 0;
1324         }
1325
1326         /* most events just get forwarded to the next state. */
1327         return next_state(iq, INIT_REQUEST_3_STATE);
1328 }
1329
1330 /**
1331  * Process the third part of the initial request handling. This state exists
1332  * as a separate state so that queries that generate stub priming events
1333  * will get the tail end of the init process but not repeat the stub priming
1334  * check.
1335  *
1336  * @param qstate: query state.
1337  * @param iq: iterator query state.
1338  * @param id: module id.
1339  * @return true, advancing the event to the QUERYTARGETS_STATE.
1340  */
1341 static int
1342 processInitRequest3(struct module_qstate* qstate, struct iter_qstate* iq,
1343         int id)
1344 {
1345         log_query_info(VERB_QUERY, "resolving (init part 3): ",
1346                 &qstate->qinfo);
1347         /* if the cache reply dp equals a validation anchor or msg has DS,
1348          * then DNSSEC RRSIGs are expected in the reply */
1349         iq->dnssec_expected = iter_indicates_dnssec(qstate->env, iq->dp,
1350                 iq->deleg_msg, iq->qchase.qclass);
1351
1352         /* If the RD flag wasn't set, then we just finish with the
1353          * cached referral as the response. */
1354         if(!(qstate->query_flags & BIT_RD) && iq->deleg_msg) {
1355                 iq->response = iq->deleg_msg;
1356                 if(verbosity >= VERB_ALGO && iq->response)
1357                         log_dns_msg("no RD requested, using delegation msg",
1358                                 &iq->response->qinfo, iq->response->rep);
1359                 if(qstate->reply_origin)
1360                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1361                 return final_state(iq);
1362         }
1363         /* After this point, unset the RD flag -- this query is going to
1364          * be sent to an auth. server. */
1365         iq->chase_flags &= ~BIT_RD;
1366
1367         /* if dnssec expected, fetch key for the trust-anchor or cached-DS */
1368         if(iq->dnssec_expected && qstate->env->cfg->prefetch_key &&
1369                 !(qstate->query_flags&BIT_CD)) {
1370                 generate_dnskey_prefetch(qstate, iq, id);
1371                 fptr_ok(fptr_whitelist_modenv_detach_subs(
1372                         qstate->env->detach_subs));
1373                 (*qstate->env->detach_subs)(qstate);
1374         }
1375
1376         /* Jump to the next state. */
1377         return next_state(iq, QUERYTARGETS_STATE);
1378 }
1379
1380 /**
1381  * Given a basic query, generate a parent-side "target" query.
1382  * These are subordinate queries for missing delegation point target addresses,
1383  * for which only the parent of the delegation provides correct IP addresses.
1384  *
1385  * @param qstate: query state.
1386  * @param iq: iterator query state.
1387  * @param id: module id.
1388  * @param name: target qname.
1389  * @param namelen: target qname length.
1390  * @param qtype: target qtype (either A or AAAA).
1391  * @param qclass: target qclass.
1392  * @return true on success, false on failure.
1393  */
1394 static int
1395 generate_parentside_target_query(struct module_qstate* qstate,
1396         struct iter_qstate* iq, int id, uint8_t* name, size_t namelen,
1397         uint16_t qtype, uint16_t qclass)
1398 {
1399         struct module_qstate* subq;
1400         if(!generate_sub_request(name, namelen, qtype, qclass, qstate,
1401                 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0))
1402                 return 0;
1403         if(subq) {
1404                 struct iter_qstate* subiq =
1405                         (struct iter_qstate*)subq->minfo[id];
1406                 /* blacklist the cache - we want to fetch parent stuff */
1407                 sock_list_insert(&subq->blacklist, NULL, 0, subq->region);
1408                 subiq->query_for_pside_glue = 1;
1409                 if(dname_subdomain_c(name, iq->dp->name)) {
1410                         subiq->dp = delegpt_copy(iq->dp, subq->region);
1411                         subiq->dnssec_expected = iter_indicates_dnssec(
1412                                 qstate->env, subiq->dp, NULL,
1413                                 subq->qinfo.qclass);
1414                         subiq->refetch_glue = 1;
1415                 } else {
1416                         subiq->dp = dns_cache_find_delegation(qstate->env,
1417                                 name, namelen, qtype, qclass, subq->region,
1418                                 &subiq->deleg_msg,
1419                                 *qstate->env->now+subq->prefetch_leeway);
1420                         /* if no dp, then it's from root, refetch unneeded */
1421                         if(subiq->dp) {
1422                                 subiq->dnssec_expected = iter_indicates_dnssec(
1423                                         qstate->env, subiq->dp, NULL,
1424                                         subq->qinfo.qclass);
1425                                 subiq->refetch_glue = 1;
1426                         }
1427                 }
1428         }
1429         log_nametypeclass(VERB_QUERY, "new pside target", name, qtype, qclass);
1430         return 1;
1431 }
1432
1433 /**
1434  * Given a basic query, generate a "target" query. These are subordinate
1435  * queries for missing delegation point target addresses.
1436  *
1437  * @param qstate: query state.
1438  * @param iq: iterator query state.
1439  * @param id: module id.
1440  * @param name: target qname.
1441  * @param namelen: target qname length.
1442  * @param qtype: target qtype (either A or AAAA).
1443  * @param qclass: target qclass.
1444  * @return true on success, false on failure.
1445  */
1446 static int
1447 generate_target_query(struct module_qstate* qstate, struct iter_qstate* iq,
1448         int id, uint8_t* name, size_t namelen, uint16_t qtype, uint16_t qclass)
1449 {
1450         struct module_qstate* subq;
1451         if(!generate_sub_request(name, namelen, qtype, qclass, qstate,
1452                 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0))
1453                 return 0;
1454         log_nametypeclass(VERB_QUERY, "new target", name, qtype, qclass);
1455         return 1;
1456 }
1457
1458 /**
1459  * Given an event at a certain state, generate zero or more target queries
1460  * for it's current delegation point.
1461  *
1462  * @param qstate: query state.
1463  * @param iq: iterator query state.
1464  * @param ie: iterator shared global environment.
1465  * @param id: module id.
1466  * @param maxtargets: The maximum number of targets to query for.
1467  *      if it is negative, there is no maximum number of targets.
1468  * @param num: returns the number of queries generated and processed,
1469  *      which may be zero if there were no missing targets.
1470  * @return false on error.
1471  */
1472 static int
1473 query_for_targets(struct module_qstate* qstate, struct iter_qstate* iq,
1474         struct iter_env* ie, int id, int maxtargets, int* num)
1475 {
1476         int query_count = 0;
1477         struct delegpt_ns* ns;
1478         int missing;
1479         int toget = 0;
1480
1481         if(iq->depth == ie->max_dependency_depth)
1482                 return 0;
1483         if(iq->depth > 0 && iq->target_count &&
1484                 iq->target_count[1] > MAX_TARGET_COUNT) {
1485                 char s[LDNS_MAX_DOMAINLEN+1];
1486                 dname_str(qstate->qinfo.qname, s);
1487                 verbose(VERB_QUERY, "request %s has exceeded the maximum "
1488                         "number of glue fetches %d", s, iq->target_count[1]);
1489                 return 0;
1490         }
1491
1492         iter_mark_cycle_targets(qstate, iq->dp);
1493         missing = (int)delegpt_count_missing_targets(iq->dp);
1494         log_assert(maxtargets != 0); /* that would not be useful */
1495
1496         /* Generate target requests. Basically, any missing targets
1497          * are queried for here, regardless if it is necessary to do
1498          * so to continue processing. */
1499         if(maxtargets < 0 || maxtargets > missing)
1500                 toget = missing;
1501         else    toget = maxtargets;
1502         if(toget == 0) {
1503                 *num = 0;
1504                 return 1;
1505         }
1506         /* select 'toget' items from the total of 'missing' items */
1507         log_assert(toget <= missing);
1508
1509         /* loop over missing targets */
1510         for(ns = iq->dp->nslist; ns; ns = ns->next) {
1511                 if(ns->resolved)
1512                         continue;
1513
1514                 /* randomly select this item with probability toget/missing */
1515                 if(!iter_ns_probability(qstate->env->rnd, toget, missing)) {
1516                         /* do not select this one, next; select toget number
1517                          * of items from a list one less in size */
1518                         missing --;
1519                         continue;
1520                 }
1521
1522                 if(ie->supports_ipv6 && !ns->got6) {
1523                         /* Send the AAAA request. */
1524                         if(!generate_target_query(qstate, iq, id,
1525                                 ns->name, ns->namelen,
1526                                 LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) {
1527                                 *num = query_count;
1528                                 if(query_count > 0)
1529                                         qstate->ext_state[id] = module_wait_subquery;
1530                                 return 0;
1531                         }
1532                         query_count++;
1533                 }
1534                 /* Send the A request. */
1535                 if(ie->supports_ipv4 && !ns->got4) {
1536                         if(!generate_target_query(qstate, iq, id,
1537                                 ns->name, ns->namelen,
1538                                 LDNS_RR_TYPE_A, iq->qchase.qclass)) {
1539                                 *num = query_count;
1540                                 if(query_count > 0)
1541                                         qstate->ext_state[id] = module_wait_subquery;
1542                                 return 0;
1543                         }
1544                         query_count++;
1545                 }
1546
1547                 /* mark this target as in progress. */
1548                 ns->resolved = 1;
1549                 missing--;
1550                 toget--;
1551                 if(toget == 0)
1552                         break;
1553         }
1554         *num = query_count;
1555         if(query_count > 0)
1556                 qstate->ext_state[id] = module_wait_subquery;
1557
1558         return 1;
1559 }
1560
1561 /** see if last resort is possible - does config allow queries to parent */
1562 static int
1563 can_have_last_resort(struct module_env* env, struct delegpt* dp,
1564         struct iter_qstate* iq)
1565 {
1566         struct delegpt* fwddp;
1567         struct iter_hints_stub* stub;
1568         /* do not process a last resort (the parent side) if a stub
1569          * or forward is configured, because we do not want to go 'above'
1570          * the configured servers */
1571         if(!dname_is_root(dp->name) && (stub = (struct iter_hints_stub*)
1572                 name_tree_find(&env->hints->tree, dp->name, dp->namelen,
1573                 dp->namelabs, iq->qchase.qclass)) &&
1574                 /* has_parent side is turned off for stub_first, where we
1575                  * are allowed to go to the parent */
1576                 stub->dp->has_parent_side_NS) {
1577                 verbose(VERB_QUERY, "configured stub servers failed -- returning SERVFAIL");
1578                 return 0;
1579         }
1580         if((fwddp = forwards_find(env->fwds, dp->name, iq->qchase.qclass)) &&
1581                 /* has_parent_side is turned off for forward_first, where
1582                  * we are allowed to go to the parent */
1583                 fwddp->has_parent_side_NS) {
1584                 verbose(VERB_QUERY, "configured forward servers failed -- returning SERVFAIL");
1585                 return 0;
1586         }
1587         return 1;
1588 }
1589
1590 /**
1591  * Called by processQueryTargets when it would like extra targets to query
1592  * but it seems to be out of options.  At last resort some less appealing
1593  * options are explored.  If there are no more options, the result is SERVFAIL
1594  *
1595  * @param qstate: query state.
1596  * @param iq: iterator query state.
1597  * @param ie: iterator shared global environment.
1598  * @param id: module id.
1599  * @return true if the event requires more request processing immediately,
1600  *         false if not.
1601  */
1602 static int
1603 processLastResort(struct module_qstate* qstate, struct iter_qstate* iq,
1604         struct iter_env* ie, int id)
1605 {
1606         struct delegpt_ns* ns;
1607         int query_count = 0;
1608         verbose(VERB_ALGO, "No more query targets, attempting last resort");
1609         log_assert(iq->dp);
1610
1611         if(!can_have_last_resort(qstate->env, iq->dp, iq)) {
1612                 /* fail -- no more targets, no more hope of targets, no hope
1613                  * of a response. */
1614                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1615         }
1616         if(!iq->dp->has_parent_side_NS && dname_is_root(iq->dp->name)) {
1617                 struct delegpt* p = hints_lookup_root(qstate->env->hints,
1618                         iq->qchase.qclass);
1619                 if(p) {
1620                         struct delegpt_ns* ns;
1621                         struct delegpt_addr* a;
1622                         iq->chase_flags &= ~BIT_RD; /* go to authorities */
1623                         for(ns = p->nslist; ns; ns=ns->next) {
1624                                 (void)delegpt_add_ns(iq->dp, qstate->region,
1625                                         ns->name, ns->lame);
1626                         }
1627                         for(a = p->target_list; a; a=a->next_target) {
1628                                 (void)delegpt_add_addr(iq->dp, qstate->region,
1629                                         &a->addr, a->addrlen, a->bogus,
1630                                         a->lame);
1631                         }
1632                 }
1633                 iq->dp->has_parent_side_NS = 1;
1634         } else if(!iq->dp->has_parent_side_NS) {
1635                 if(!iter_lookup_parent_NS_from_cache(qstate->env, iq->dp,
1636                         qstate->region, &qstate->qinfo)
1637                         || !iq->dp->has_parent_side_NS) {
1638                         /* if: malloc failure in lookup go up to try */
1639                         /* if: no parent NS in cache - go up one level */
1640                         verbose(VERB_ALGO, "try to grab parent NS");
1641                         iq->store_parent_NS = iq->dp;
1642                         iq->chase_flags &= ~BIT_RD; /* go to authorities */
1643                         iq->deleg_msg = NULL;
1644                         iq->refetch_glue = 1;
1645                         iq->query_restart_count++;
1646                         iq->sent_count = 0;
1647                         if(qstate->env->cfg->qname_minimisation)
1648                                 iq->minimisation_state = INIT_MINIMISE_STATE;
1649                         return next_state(iq, INIT_REQUEST_STATE);
1650                 }
1651         }
1652         /* see if that makes new names available */
1653         if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
1654                 qstate->region, iq->dp))
1655                 log_err("out of memory in cache_fill_missing");
1656         if(iq->dp->usable_list) {
1657                 verbose(VERB_ALGO, "try parent-side-name, w. glue from cache");
1658                 return next_state(iq, QUERYTARGETS_STATE);
1659         }
1660         /* try to fill out parent glue from cache */
1661         if(iter_lookup_parent_glue_from_cache(qstate->env, iq->dp,
1662                 qstate->region, &qstate->qinfo)) {
1663                 /* got parent stuff from cache, see if we can continue */
1664                 verbose(VERB_ALGO, "try parent-side glue from cache");
1665                 return next_state(iq, QUERYTARGETS_STATE);
1666         }
1667         /* query for an extra name added by the parent-NS record */
1668         if(delegpt_count_missing_targets(iq->dp) > 0) {
1669                 int qs = 0;
1670                 verbose(VERB_ALGO, "try parent-side target name");
1671                 if(!query_for_targets(qstate, iq, ie, id, 1, &qs)) {
1672                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1673                 }
1674                 iq->num_target_queries += qs;
1675                 target_count_increase(iq, qs);
1676                 if(qs != 0) {
1677                         qstate->ext_state[id] = module_wait_subquery;
1678                         return 0; /* and wait for them */
1679                 }
1680         }
1681         if(iq->depth == ie->max_dependency_depth) {
1682                 verbose(VERB_QUERY, "maxdepth and need more nameservers, fail");
1683                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1684         }
1685         if(iq->depth > 0 && iq->target_count &&
1686                 iq->target_count[1] > MAX_TARGET_COUNT) {
1687                 char s[LDNS_MAX_DOMAINLEN+1];
1688                 dname_str(qstate->qinfo.qname, s);
1689                 verbose(VERB_QUERY, "request %s has exceeded the maximum "
1690                         "number of glue fetches %d", s, iq->target_count[1]);
1691                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1692         }
1693         /* mark cycle targets for parent-side lookups */
1694         iter_mark_pside_cycle_targets(qstate, iq->dp);
1695         /* see if we can issue queries to get nameserver addresses */
1696         /* this lookup is not randomized, but sequential. */
1697         for(ns = iq->dp->nslist; ns; ns = ns->next) {
1698                 /* query for parent-side A and AAAA for nameservers */
1699                 if(ie->supports_ipv6 && !ns->done_pside6) {
1700                         /* Send the AAAA request. */
1701                         if(!generate_parentside_target_query(qstate, iq, id,
1702                                 ns->name, ns->namelen,
1703                                 LDNS_RR_TYPE_AAAA, iq->qchase.qclass))
1704                                 return error_response(qstate, id,
1705                                         LDNS_RCODE_SERVFAIL);
1706                         ns->done_pside6 = 1;
1707                         query_count++;
1708                 }
1709                 if(ie->supports_ipv4 && !ns->done_pside4) {
1710                         /* Send the A request. */
1711                         if(!generate_parentside_target_query(qstate, iq, id,
1712                                 ns->name, ns->namelen,
1713                                 LDNS_RR_TYPE_A, iq->qchase.qclass))
1714                                 return error_response(qstate, id,
1715                                         LDNS_RCODE_SERVFAIL);
1716                         ns->done_pside4 = 1;
1717                         query_count++;
1718                 }
1719                 if(query_count != 0) { /* suspend to await results */
1720                         verbose(VERB_ALGO, "try parent-side glue lookup");
1721                         iq->num_target_queries += query_count;
1722                         target_count_increase(iq, query_count);
1723                         qstate->ext_state[id] = module_wait_subquery;
1724                         return 0;
1725                 }
1726         }
1727
1728         /* if this was a parent-side glue query itself, then store that
1729          * failure in cache. */
1730         if(!qstate->no_cache_store && iq->query_for_pside_glue
1731                 && !iq->pside_glue)
1732                         iter_store_parentside_neg(qstate->env, &qstate->qinfo,
1733                                 iq->deleg_msg?iq->deleg_msg->rep:
1734                                 (iq->response?iq->response->rep:NULL));
1735
1736         verbose(VERB_QUERY, "out of query targets -- returning SERVFAIL");
1737         /* fail -- no more targets, no more hope of targets, no hope
1738          * of a response. */
1739         return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1740 }
1741
1742 /**
1743  * Try to find the NS record set that will resolve a qtype DS query. Due
1744  * to grandparent/grandchild reasons we did not get a proper lookup right
1745  * away.  We need to create type NS queries until we get the right parent
1746  * for this lookup.  We remove labels from the query to find the right point.
1747  * If we end up at the old dp name, then there is no solution.
1748  *
1749  * @param qstate: query state.
1750  * @param iq: iterator query state.
1751  * @param id: module id.
1752  * @return true if the event requires more immediate processing, false if
1753  *         not. This is generally only true when forwarding the request to
1754  *         the final state (i.e., on answer).
1755  */
1756 static int
1757 processDSNSFind(struct module_qstate* qstate, struct iter_qstate* iq, int id)
1758 {
1759         struct module_qstate* subq = NULL;
1760         verbose(VERB_ALGO, "processDSNSFind");
1761
1762         if(!iq->dsns_point) {
1763                 /* initialize */
1764                 iq->dsns_point = iq->qchase.qname;
1765                 iq->dsns_point_len = iq->qchase.qname_len;
1766         }
1767         /* robustcheck for internal error: we are not underneath the dp */
1768         if(!dname_subdomain_c(iq->dsns_point, iq->dp->name)) {
1769                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1770         }
1771
1772         /* go up one (more) step, until we hit the dp, if so, end */
1773         dname_remove_label(&iq->dsns_point, &iq->dsns_point_len);
1774         if(query_dname_compare(iq->dsns_point, iq->dp->name) == 0) {
1775                 /* there was no inbetween nameserver, use the old delegation
1776                  * point again.  And this time, because dsns_point is nonNULL
1777                  * we are going to accept the (bad) result */
1778                 iq->state = QUERYTARGETS_STATE;
1779                 return 1;
1780         }
1781         iq->state = DSNS_FIND_STATE;
1782
1783         /* spawn NS lookup (validation not needed, this is for DS lookup) */
1784         log_nametypeclass(VERB_ALGO, "fetch nameservers",
1785                 iq->dsns_point, LDNS_RR_TYPE_NS, iq->qchase.qclass);
1786         if(!generate_sub_request(iq->dsns_point, iq->dsns_point_len,
1787                 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
1788                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0)) {
1789                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1790         }
1791
1792         return 0;
1793 }
1794
1795 /**
1796  * This is the request event state where the request will be sent to one of
1797  * its current query targets. This state also handles issuing target lookup
1798  * queries for missing target IP addresses. Queries typically iterate on
1799  * this state, both when they are just trying different targets for a given
1800  * delegation point, and when they change delegation points. This state
1801  * roughly corresponds to RFC 1034 algorithm steps 3 and 4.
1802  *
1803  * @param qstate: query state.
1804  * @param iq: iterator query state.
1805  * @param ie: iterator shared global environment.
1806  * @param id: module id.
1807  * @return true if the event requires more request processing immediately,
1808  *         false if not. This state only returns true when it is generating
1809  *         a SERVFAIL response because the query has hit a dead end.
1810  */
1811 static int
1812 processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
1813         struct iter_env* ie, int id)
1814 {
1815         int tf_policy;
1816         struct delegpt_addr* target;
1817         struct outbound_entry* outq;
1818
1819         /* NOTE: a request will encounter this state for each target it
1820          * needs to send a query to. That is, at least one per referral,
1821          * more if some targets timeout or return throwaway answers. */
1822
1823         log_query_info(VERB_QUERY, "processQueryTargets:", &qstate->qinfo);
1824         verbose(VERB_ALGO, "processQueryTargets: targetqueries %d, "
1825                 "currentqueries %d sentcount %d", iq->num_target_queries,
1826                 iq->num_current_queries, iq->sent_count);
1827
1828         /* Make sure that we haven't run away */
1829         /* FIXME: is this check even necessary? */
1830         if(iq->referral_count > MAX_REFERRAL_COUNT) {
1831                 verbose(VERB_QUERY, "request has exceeded the maximum "
1832                         "number of referrrals with %d", iq->referral_count);
1833                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1834         }
1835         if(iq->sent_count > MAX_SENT_COUNT) {
1836                 verbose(VERB_QUERY, "request has exceeded the maximum "
1837                         "number of sends with %d", iq->sent_count);
1838                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1839         }
1840
1841         /* Make sure we have a delegation point, otherwise priming failed
1842          * or another failure occurred */
1843         if(!iq->dp) {
1844                 verbose(VERB_QUERY, "Failed to get a delegation, giving up");
1845                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1846         }
1847         if(!ie->supports_ipv6)
1848                 delegpt_no_ipv6(iq->dp);
1849         if(!ie->supports_ipv4)
1850                 delegpt_no_ipv4(iq->dp);
1851         delegpt_log(VERB_ALGO, iq->dp);
1852
1853         if(iq->num_current_queries>0) {
1854                 /* already busy answering a query, this restart is because
1855                  * more delegpt addrs became available, wait for existing
1856                  * query. */
1857                 verbose(VERB_ALGO, "woke up, but wait for outstanding query");
1858                 qstate->ext_state[id] = module_wait_reply;
1859                 return 0;
1860         }
1861
1862         tf_policy = 0;
1863         /* < not <=, because although the array is large enough for <=, the
1864          * generated query will immediately be discarded due to depth and
1865          * that servfail is cached, which is not good as opportunism goes. */
1866         if(iq->depth < ie->max_dependency_depth
1867                 && iq->sent_count < TARGET_FETCH_STOP) {
1868                 tf_policy = ie->target_fetch_policy[iq->depth];
1869         }
1870
1871         /* if in 0x20 fallback get as many targets as possible */
1872         if(iq->caps_fallback) {
1873                 int extra = 0;
1874                 size_t naddr, nres, navail;
1875                 if(!query_for_targets(qstate, iq, ie, id, -1, &extra)) {
1876                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1877                 }
1878                 iq->num_target_queries += extra;
1879                 target_count_increase(iq, extra);
1880                 if(iq->num_target_queries > 0) {
1881                         /* wait to get all targets, we want to try em */
1882                         verbose(VERB_ALGO, "wait for all targets for fallback");
1883                         qstate->ext_state[id] = module_wait_reply;
1884                         return 0;
1885                 }
1886                 /* did we do enough fallback queries already? */
1887                 delegpt_count_addr(iq->dp, &naddr, &nres, &navail);
1888                 /* the current caps_server is the number of fallbacks sent.
1889                  * the original query is one that matched too, so we have
1890                  * caps_server+1 number of matching queries now */
1891                 if(iq->caps_server+1 >= naddr*3 ||
1892                         iq->caps_server*2+2 >= MAX_SENT_COUNT) {
1893                         /* *2 on sentcount check because ipv6 may fail */
1894                         /* we're done, process the response */
1895                         verbose(VERB_ALGO, "0x20 fallback had %d responses "
1896                                 "match for %d wanted, done.",
1897                                 (int)iq->caps_server+1, (int)naddr*3);
1898                         iq->response = iq->caps_response;
1899                         iq->caps_fallback = 0;
1900                         iter_dec_attempts(iq->dp, 3); /* space for fallback */
1901                         iq->num_current_queries++; /* RespState decrements it*/
1902                         iq->referral_count++; /* make sure we don't loop */
1903                         iq->sent_count = 0;
1904                         iq->state = QUERY_RESP_STATE;
1905                         return 1;
1906                 }
1907                 verbose(VERB_ALGO, "0x20 fallback number %d",
1908                         (int)iq->caps_server);
1909
1910         /* if there is a policy to fetch missing targets
1911          * opportunistically, do it. we rely on the fact that once a
1912          * query (or queries) for a missing name have been issued,
1913          * they will not show up again. */
1914         } else if(tf_policy != 0) {
1915                 int extra = 0;
1916                 verbose(VERB_ALGO, "attempt to get extra %d targets",
1917                         tf_policy);
1918                 (void)query_for_targets(qstate, iq, ie, id, tf_policy, &extra);
1919                 /* errors ignored, these targets are not strictly necessary for
1920                  * this result, we do not have to reply with SERVFAIL */
1921                 iq->num_target_queries += extra;
1922                 target_count_increase(iq, extra);
1923         }
1924
1925         /* Add the current set of unused targets to our queue. */
1926         delegpt_add_unused_targets(iq->dp);
1927
1928         /* Select the next usable target, filtering out unsuitable targets. */
1929         target = iter_server_selection(ie, qstate->env, iq->dp,
1930                 iq->dp->name, iq->dp->namelen, iq->qchase.qtype,
1931                 &iq->dnssec_lame_query, &iq->chase_to_rd,
1932                 iq->num_target_queries, qstate->blacklist);
1933
1934         /* If no usable target was selected... */
1935         if(!target) {
1936                 /* Here we distinguish between three states: generate a new
1937                  * target query, just wait, or quit (with a SERVFAIL).
1938                  * We have the following information: number of active
1939                  * target queries, number of active current queries,
1940                  * the presence of missing targets at this delegation
1941                  * point, and the given query target policy. */
1942
1943                 /* Check for the wait condition. If this is true, then
1944                  * an action must be taken. */
1945                 if(iq->num_target_queries==0 && iq->num_current_queries==0) {
1946                         /* If there is nothing to wait for, then we need
1947                          * to distinguish between generating (a) new target
1948                          * query, or failing. */
1949                         if(delegpt_count_missing_targets(iq->dp) > 0) {
1950                                 int qs = 0;
1951                                 verbose(VERB_ALGO, "querying for next "
1952                                         "missing target");
1953                                 if(!query_for_targets(qstate, iq, ie, id,
1954                                         1, &qs)) {
1955                                         return error_response(qstate, id,
1956                                                 LDNS_RCODE_SERVFAIL);
1957                                 }
1958                                 if(qs == 0 &&
1959                                    delegpt_count_missing_targets(iq->dp) == 0){
1960                                         /* it looked like there were missing
1961                                          * targets, but they did not turn up.
1962                                          * Try the bad choices again (if any),
1963                                          * when we get back here missing==0,
1964                                          * so this is not a loop. */
1965                                         return 1;
1966                                 }
1967                                 iq->num_target_queries += qs;
1968                                 target_count_increase(iq, qs);
1969                         }
1970                         /* Since a target query might have been made, we
1971                          * need to check again. */
1972                         if(iq->num_target_queries == 0) {
1973                                 /* if in capsforid fallback, instead of last
1974                                  * resort, we agree with the current reply
1975                                  * we have (if any) (our count of addrs bad)*/
1976                                 if(iq->caps_fallback && iq->caps_reply) {
1977                                         /* we're done, process the response */
1978                                         verbose(VERB_ALGO, "0x20 fallback had %d responses, "
1979                                                 "but no more servers except "
1980                                                 "last resort, done.",
1981                                                 (int)iq->caps_server+1);
1982                                         iq->response = iq->caps_response;
1983                                         iq->caps_fallback = 0;
1984                                         iter_dec_attempts(iq->dp, 3); /* space for fallback */
1985                                         iq->num_current_queries++; /* RespState decrements it*/
1986                                         iq->referral_count++; /* make sure we don't loop */
1987                                         iq->sent_count = 0;
1988                                         iq->state = QUERY_RESP_STATE;
1989                                         return 1;
1990                                 }
1991                                 return processLastResort(qstate, iq, ie, id);
1992                         }
1993                 }
1994
1995                 /* otherwise, we have no current targets, so submerge
1996                  * until one of the target or direct queries return. */
1997                 if(iq->num_target_queries>0 && iq->num_current_queries>0) {
1998                         verbose(VERB_ALGO, "no current targets -- waiting "
1999                                 "for %d targets to resolve or %d outstanding"
2000                                 " queries to respond", iq->num_target_queries,
2001                                 iq->num_current_queries);
2002                         qstate->ext_state[id] = module_wait_reply;
2003                 } else if(iq->num_target_queries>0) {
2004                         verbose(VERB_ALGO, "no current targets -- waiting "
2005                                 "for %d targets to resolve.",
2006                                 iq->num_target_queries);
2007                         qstate->ext_state[id] = module_wait_subquery;
2008                 } else {
2009                         verbose(VERB_ALGO, "no current targets -- waiting "
2010                                 "for %d outstanding queries to respond.",
2011                                 iq->num_current_queries);
2012                         qstate->ext_state[id] = module_wait_reply;
2013                 }
2014                 return 0;
2015         }
2016
2017         /* if not forwarding, check ratelimits per delegationpoint name */
2018         if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok) {
2019                 if(!infra_ratelimit_inc(qstate->env->infra_cache, iq->dp->name,
2020                         iq->dp->namelen, *qstate->env->now)) {
2021                         verbose(VERB_ALGO, "query exceeded ratelimits");
2022                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2023                 }
2024         }
2025
2026         if(iq->minimisation_state == INIT_MINIMISE_STATE) {
2027                 /* (Re)set qinfo_out to (new) delegation point, except when
2028                  * qinfo_out is already a subdomain of dp. This happens when
2029                  * increasing by more than one label at once (QNAMEs with more
2030                  * than MAX_MINIMISE_COUNT labels). */
2031                 if(!(iq->qinfo_out.qname_len
2032                         && dname_subdomain_c(iq->qchase.qname,
2033                                 iq->qinfo_out.qname)
2034                         && dname_subdomain_c(iq->qinfo_out.qname,
2035                                 iq->dp->name))) {
2036                         iq->qinfo_out.qname = iq->dp->name;
2037                         iq->qinfo_out.qname_len = iq->dp->namelen;
2038                         iq->qinfo_out.qtype = LDNS_RR_TYPE_A;
2039                         iq->qinfo_out.qclass = iq->qchase.qclass;
2040                         iq->qinfo_out.local_alias = NULL;
2041                         iq->minimise_count = 0;
2042                 }
2043
2044                 iq->minimisation_state = MINIMISE_STATE;
2045         }
2046         if(iq->minimisation_state == MINIMISE_STATE) {
2047                 int qchaselabs = dname_count_labels(iq->qchase.qname);
2048                 int labdiff = qchaselabs -
2049                         dname_count_labels(iq->qinfo_out.qname);
2050
2051                 iq->qinfo_out.qname = iq->qchase.qname;
2052                 iq->qinfo_out.qname_len = iq->qchase.qname_len;
2053                 iq->minimise_count++;
2054                 iq->minimise_timeout_count = 0;
2055
2056                 iter_dec_attempts(iq->dp, 1);
2057
2058                 /* Limit number of iterations for QNAMEs with more
2059                  * than MAX_MINIMISE_COUNT labels. Send first MINIMISE_ONE_LAB
2060                  * labels of QNAME always individually.
2061                  */
2062                 if(qchaselabs > MAX_MINIMISE_COUNT && labdiff > 1 &&
2063                         iq->minimise_count > MINIMISE_ONE_LAB) {
2064                         if(iq->minimise_count < MAX_MINIMISE_COUNT) {
2065                                 int multilabs = qchaselabs - 1 -
2066                                         MINIMISE_ONE_LAB;
2067                                 int extralabs = multilabs /
2068                                         MINIMISE_MULTIPLE_LABS;
2069
2070                                 if (MAX_MINIMISE_COUNT - iq->minimise_count >=
2071                                         multilabs % MINIMISE_MULTIPLE_LABS)
2072                                         /* Default behaviour is to add 1 label
2073                                          * every iteration. Therefore, decrement
2074                                          * the extralabs by 1 */
2075                                         extralabs--;
2076                                 if (extralabs < labdiff)
2077                                         labdiff -= extralabs;
2078                                 else
2079                                         labdiff = 1;
2080                         }
2081                         /* Last minimised iteration, send all labels with
2082                          * QTYPE=NS */
2083                         else
2084                                 labdiff = 1;
2085                 }
2086
2087                 if(labdiff > 1) {
2088                         verbose(VERB_QUERY, "removing %d labels", labdiff-1);
2089                         dname_remove_labels(&iq->qinfo_out.qname,
2090                                 &iq->qinfo_out.qname_len,
2091                                 labdiff-1);
2092                 }
2093                 if(labdiff < 1 || (labdiff < 2
2094                         && (iq->qchase.qtype == LDNS_RR_TYPE_DS
2095                         || iq->qchase.qtype == LDNS_RR_TYPE_A)))
2096                         /* Stop minimising this query, resolve "as usual" */
2097                         iq->minimisation_state = DONOT_MINIMISE_STATE;
2098                 else if(!qstate->no_cache_lookup) {
2099                         struct dns_msg* msg = dns_cache_lookup(qstate->env,
2100                                 iq->qinfo_out.qname, iq->qinfo_out.qname_len,
2101                                 iq->qinfo_out.qtype, iq->qinfo_out.qclass,
2102                                 qstate->query_flags, qstate->region,
2103                                 qstate->env->scratch);
2104                         if(msg && msg->rep->an_numrrsets == 0
2105                                 && FLAGS_GET_RCODE(msg->rep->flags) ==
2106                                 LDNS_RCODE_NOERROR)
2107                                 /* no need to send query if it is already
2108                                  * cached as NOERROR/NODATA */
2109                                 return 1;
2110                 }
2111         }
2112         if(iq->minimisation_state == SKIP_MINIMISE_STATE) {
2113                 iq->minimise_timeout_count++;
2114                 if(iq->minimise_timeout_count < MAX_MINIMISE_TIMEOUT_COUNT)
2115                         /* Do not increment qname, continue incrementing next
2116                          * iteration */
2117                         iq->minimisation_state = MINIMISE_STATE;
2118                 else if(!qstate->env->cfg->qname_minimisation_strict)
2119                         /* Too many time-outs detected for this QNAME and QTYPE.
2120                          * We give up, disable QNAME minimisation. */
2121                         iq->minimisation_state = DONOT_MINIMISE_STATE;
2122         }
2123         if(iq->minimisation_state == DONOT_MINIMISE_STATE)
2124                 iq->qinfo_out = iq->qchase;
2125
2126         /* We have a valid target. */
2127         if(verbosity >= VERB_QUERY) {
2128                 log_query_info(VERB_QUERY, "sending query:", &iq->qinfo_out);
2129                 log_name_addr(VERB_QUERY, "sending to target:", iq->dp->name,
2130                         &target->addr, target->addrlen);
2131                 verbose(VERB_ALGO, "dnssec status: %s%s",
2132                         iq->dnssec_expected?"expected": "not expected",
2133                         iq->dnssec_lame_query?" but lame_query anyway": "");
2134         }
2135         fptr_ok(fptr_whitelist_modenv_send_query(qstate->env->send_query));
2136         outq = (*qstate->env->send_query)(&iq->qinfo_out,
2137                 iq->chase_flags | (iq->chase_to_rd?BIT_RD:0),
2138                 /* unset CD if to forwarder(RD set) and not dnssec retry
2139                  * (blacklist nonempty) and no trust-anchors are configured
2140                  * above the qname or on the first attempt when dnssec is on */
2141                 EDNS_DO| ((iq->chase_to_rd||(iq->chase_flags&BIT_RD)!=0)&&
2142                 !qstate->blacklist&&(!iter_indicates_dnssec_fwd(qstate->env,
2143                 &iq->qinfo_out)||target->attempts==1)?0:BIT_CD),
2144                 iq->dnssec_expected, iq->caps_fallback || is_caps_whitelisted(
2145                 ie, iq), &target->addr, target->addrlen,
2146                 iq->dp->name, iq->dp->namelen,
2147                 (iq->dp->ssl_upstream || qstate->env->cfg->ssl_upstream), qstate);
2148         if(!outq) {
2149                 log_addr(VERB_DETAIL, "error sending query to auth server",
2150                         &target->addr, target->addrlen);
2151                 if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok)
2152                     infra_ratelimit_dec(qstate->env->infra_cache, iq->dp->name,
2153                         iq->dp->namelen, *qstate->env->now);
2154                 return next_state(iq, QUERYTARGETS_STATE);
2155         }
2156         outbound_list_insert(&iq->outlist, outq);
2157         iq->num_current_queries++;
2158         iq->sent_count++;
2159         qstate->ext_state[id] = module_wait_reply;
2160
2161         return 0;
2162 }
2163
2164 /** find NS rrset in given list */
2165 static struct ub_packed_rrset_key*
2166 find_NS(struct reply_info* rep, size_t from, size_t to)
2167 {
2168         size_t i;
2169         for(i=from; i<to; i++) {
2170                 if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NS)
2171                         return rep->rrsets[i];
2172         }
2173         return NULL;
2174 }
2175
2176
2177 /**
2178  * Process the query response. All queries end up at this state first. This
2179  * process generally consists of analyzing the response and routing the
2180  * event to the next state (either bouncing it back to a request state, or
2181  * terminating the processing for this event).
2182  *
2183  * @param qstate: query state.
2184  * @param iq: iterator query state.
2185  * @param id: module id.
2186  * @return true if the event requires more immediate processing, false if
2187  *         not. This is generally only true when forwarding the request to
2188  *         the final state (i.e., on answer).
2189  */
2190 static int
2191 processQueryResponse(struct module_qstate* qstate, struct iter_qstate* iq,
2192         int id)
2193 {
2194         int dnsseclame = 0;
2195         enum response_type type;
2196         iq->num_current_queries--;
2197
2198         if(!inplace_cb_query_response_call(qstate->env, qstate, iq->response))
2199                 log_err("unable to call query_response callback");
2200
2201         if(iq->response == NULL) {
2202                 /* Don't increment qname when QNAME minimisation is enabled */
2203                 if(qstate->env->cfg->qname_minimisation)
2204                         iq->minimisation_state = SKIP_MINIMISE_STATE;
2205                 iq->chase_to_rd = 0;
2206                 iq->dnssec_lame_query = 0;
2207                 verbose(VERB_ALGO, "query response was timeout");
2208                 return next_state(iq, QUERYTARGETS_STATE);
2209         }
2210         type = response_type_from_server(
2211                 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd),
2212                 iq->response, &iq->qchase, iq->dp);
2213         iq->chase_to_rd = 0;
2214         if(type == RESPONSE_TYPE_REFERRAL && (iq->chase_flags&BIT_RD)) {
2215                 /* When forwarding (RD bit is set), we handle referrals
2216                  * differently. No queries should be sent elsewhere */
2217                 type = RESPONSE_TYPE_ANSWER;
2218         }
2219         if(!qstate->env->cfg->disable_dnssec_lame_check && iq->dnssec_expected
2220                 && !iq->dnssec_lame_query &&
2221                 !(iq->chase_flags&BIT_RD)
2222                 && iq->sent_count < DNSSEC_LAME_DETECT_COUNT
2223                 && type != RESPONSE_TYPE_LAME
2224                 && type != RESPONSE_TYPE_REC_LAME
2225                 && type != RESPONSE_TYPE_THROWAWAY
2226                 && type != RESPONSE_TYPE_UNTYPED) {
2227                 /* a possible answer, see if it is missing DNSSEC */
2228                 /* but not when forwarding, so we dont mark fwder lame */
2229                 if(!iter_msg_has_dnssec(iq->response)) {
2230                         /* Mark this address as dnsseclame in this dp,
2231                          * because that will make serverselection disprefer
2232                          * it, but also, once it is the only final option,
2233                          * use dnssec-lame-bypass if it needs to query there.*/
2234                         if(qstate->reply) {
2235                                 struct delegpt_addr* a = delegpt_find_addr(
2236                                         iq->dp, &qstate->reply->addr,
2237                                         qstate->reply->addrlen);
2238                                 if(a) a->dnsseclame = 1;
2239                         }
2240                         /* test the answer is from the zone we expected,
2241                          * otherwise, (due to parent,child on same server), we
2242                          * might mark the server,zone lame inappropriately */
2243                         if(!iter_msg_from_zone(iq->response, iq->dp, type,
2244                                 iq->qchase.qclass))
2245                                 qstate->reply = NULL;
2246                         type = RESPONSE_TYPE_LAME;
2247                         dnsseclame = 1;
2248                 }
2249         } else iq->dnssec_lame_query = 0;
2250         /* see if referral brings us close to the target */
2251         if(type == RESPONSE_TYPE_REFERRAL) {
2252                 struct ub_packed_rrset_key* ns = find_NS(
2253                         iq->response->rep, iq->response->rep->an_numrrsets,
2254                         iq->response->rep->an_numrrsets
2255                         + iq->response->rep->ns_numrrsets);
2256                 if(!ns) ns = find_NS(iq->response->rep, 0,
2257                                 iq->response->rep->an_numrrsets);
2258                 if(!ns || !dname_strict_subdomain_c(ns->rk.dname, iq->dp->name)
2259                         || !dname_subdomain_c(iq->qchase.qname, ns->rk.dname)){
2260                         verbose(VERB_ALGO, "bad referral, throwaway");
2261                         type = RESPONSE_TYPE_THROWAWAY;
2262                 } else
2263                         iter_scrub_ds(iq->response, ns, iq->dp->name);
2264         } else iter_scrub_ds(iq->response, NULL, NULL);
2265         if(type == RESPONSE_TYPE_THROWAWAY &&
2266                 FLAGS_GET_RCODE(iq->response->rep->flags) == LDNS_RCODE_YXDOMAIN) {
2267                 /* YXDOMAIN is a permanent error, no need to retry */
2268                 type = RESPONSE_TYPE_ANSWER;
2269         }
2270         if(type == RESPONSE_TYPE_CNAME && iq->response->rep->an_numrrsets >= 1
2271                 && ntohs(iq->response->rep->rrsets[0]->rk.type) == LDNS_RR_TYPE_DNAME) {
2272                 uint8_t* sname = NULL;
2273                 size_t snamelen = 0;
2274                 get_cname_target(iq->response->rep->rrsets[0], &sname,
2275                         &snamelen);
2276                 if(snamelen && dname_subdomain_c(sname, iq->response->rep->rrsets[0]->rk.dname)) {
2277                         /* DNAME to a subdomain loop; do not recurse */
2278                         type = RESPONSE_TYPE_ANSWER;
2279                 }
2280         }
2281
2282         /* handle each of the type cases */
2283         if(type == RESPONSE_TYPE_ANSWER) {
2284                 /* ANSWER type responses terminate the query algorithm,
2285                  * so they sent on their */
2286                 if(verbosity >= VERB_DETAIL) {
2287                         verbose(VERB_DETAIL, "query response was %s",
2288                                 FLAGS_GET_RCODE(iq->response->rep->flags)
2289                                 ==LDNS_RCODE_NXDOMAIN?"NXDOMAIN ANSWER":
2290                                 (iq->response->rep->an_numrrsets?"ANSWER":
2291                                 "nodata ANSWER"));
2292                 }
2293                 /* if qtype is DS, check we have the right level of answer,
2294                  * like grandchild answer but we need the middle, reject it */
2295                 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
2296                         && !(iq->chase_flags&BIT_RD)
2297                         && iter_ds_toolow(iq->response, iq->dp)
2298                         && iter_dp_cangodown(&iq->qchase, iq->dp)) {
2299                         /* close down outstanding requests to be discarded */
2300                         outbound_list_clear(&iq->outlist);
2301                         iq->num_current_queries = 0;
2302                         fptr_ok(fptr_whitelist_modenv_detach_subs(
2303                                 qstate->env->detach_subs));
2304                         (*qstate->env->detach_subs)(qstate);
2305                         iq->num_target_queries = 0;
2306                         return processDSNSFind(qstate, iq, id);
2307                 }
2308                 if(!qstate->no_cache_store)
2309                         iter_dns_store(qstate->env, &iq->response->qinfo,
2310                                 iq->response->rep, 0, qstate->prefetch_leeway,
2311                                 iq->dp&&iq->dp->has_parent_side_NS,
2312                                 qstate->region, qstate->query_flags);
2313                 /* close down outstanding requests to be discarded */
2314                 outbound_list_clear(&iq->outlist);
2315                 iq->num_current_queries = 0;
2316                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2317                         qstate->env->detach_subs));
2318                 (*qstate->env->detach_subs)(qstate);
2319                 iq->num_target_queries = 0;
2320                 if(qstate->reply)
2321                         sock_list_insert(&qstate->reply_origin,
2322                                 &qstate->reply->addr, qstate->reply->addrlen,
2323                                 qstate->region);
2324                 if(iq->minimisation_state != DONOT_MINIMISE_STATE) {
2325                         if(FLAGS_GET_RCODE(iq->response->rep->flags) !=
2326                                 LDNS_RCODE_NOERROR) {
2327                                 if(qstate->env->cfg->qname_minimisation_strict)
2328                                         return final_state(iq);
2329                                 /* Best effort qname-minimisation.
2330                                  * Stop minimising and send full query when
2331                                  * RCODE is not NOERROR. */
2332                                 iq->minimisation_state = DONOT_MINIMISE_STATE;
2333                         }
2334                         if(FLAGS_GET_RCODE(iq->response->rep->flags) ==
2335                                 LDNS_RCODE_NXDOMAIN) {
2336                                 /* Stop resolving when NXDOMAIN is DNSSEC
2337                                  * signed. Based on assumption that namservers
2338                                  * serving signed zones do not return NXDOMAIN
2339                                  * for empty-non-terminals. */
2340                                 if(iq->dnssec_expected)
2341                                         return final_state(iq);
2342                                 /* Make subrequest to validate intermediate
2343                                  * NXDOMAIN if harden-below-nxdomain is
2344                                  * enabled. */
2345                                 if(qstate->env->cfg->harden_below_nxdomain) {
2346                                         struct module_qstate* subq = NULL;
2347                                         log_query_info(VERB_QUERY,
2348                                                 "schedule NXDOMAIN validation:",
2349                                                 &iq->response->qinfo);
2350                                         if(!generate_sub_request(
2351                                                 iq->response->qinfo.qname,
2352                                                 iq->response->qinfo.qname_len,
2353                                                 iq->response->qinfo.qtype,
2354                                                 iq->response->qinfo.qclass,
2355                                                 qstate, id, iq,
2356                                                 INIT_REQUEST_STATE,
2357                                                 FINISHED_STATE, &subq, 1))
2358                                                 verbose(VERB_ALGO,
2359                                                 "could not validate NXDOMAIN "
2360                                                 "response");
2361                                 }
2362                         }
2363                         return next_state(iq, QUERYTARGETS_STATE);
2364                 }
2365                 return final_state(iq);
2366         } else if(type == RESPONSE_TYPE_REFERRAL) {
2367                 /* REFERRAL type responses get a reset of the
2368                  * delegation point, and back to the QUERYTARGETS_STATE. */
2369                 verbose(VERB_DETAIL, "query response was REFERRAL");
2370
2371                 if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok) {
2372                         /* we have a referral, no ratelimit, we can send
2373                          * our queries to the given name */
2374                         infra_ratelimit_dec(qstate->env->infra_cache,
2375                                 iq->dp->name, iq->dp->namelen,
2376                                 *qstate->env->now);
2377                 }
2378
2379                 /* if hardened, only store referral if we asked for it */
2380                 if(!qstate->no_cache_store &&
2381                 (!qstate->env->cfg->harden_referral_path ||
2382                     (  qstate->qinfo.qtype == LDNS_RR_TYPE_NS
2383                         && (qstate->query_flags&BIT_RD)
2384                         && !(qstate->query_flags&BIT_CD)
2385                            /* we know that all other NS rrsets are scrubbed
2386                             * away, thus on referral only one is left.
2387                             * see if that equals the query name... */
2388                         && ( /* auth section, but sometimes in answer section*/
2389                           reply_find_rrset_section_ns(iq->response->rep,
2390                                 iq->qchase.qname, iq->qchase.qname_len,
2391                                 LDNS_RR_TYPE_NS, iq->qchase.qclass)
2392                           || reply_find_rrset_section_an(iq->response->rep,
2393                                 iq->qchase.qname, iq->qchase.qname_len,
2394                                 LDNS_RR_TYPE_NS, iq->qchase.qclass)
2395                           )
2396                     ))) {
2397                         /* Store the referral under the current query */
2398                         /* no prefetch-leeway, since its not the answer */
2399                         iter_dns_store(qstate->env, &iq->response->qinfo,
2400                                 iq->response->rep, 1, 0, 0, NULL, 0);
2401                         if(iq->store_parent_NS)
2402                                 iter_store_parentside_NS(qstate->env,
2403                                         iq->response->rep);
2404                         if(qstate->env->neg_cache)
2405                                 val_neg_addreferral(qstate->env->neg_cache,
2406                                         iq->response->rep, iq->dp->name);
2407                 }
2408                 /* store parent-side-in-zone-glue, if directly queried for */
2409                 if(!qstate->no_cache_store && iq->query_for_pside_glue
2410                         && !iq->pside_glue) {
2411                                 iq->pside_glue = reply_find_rrset(iq->response->rep,
2412                                         iq->qchase.qname, iq->qchase.qname_len,
2413                                         iq->qchase.qtype, iq->qchase.qclass);
2414                                 if(iq->pside_glue) {
2415                                         log_rrset_key(VERB_ALGO, "found parent-side "
2416                                                 "glue", iq->pside_glue);
2417                                         iter_store_parentside_rrset(qstate->env,
2418                                                 iq->pside_glue);
2419                                 }
2420                 }
2421
2422                 /* Reset the event state, setting the current delegation
2423                  * point to the referral. */
2424                 iq->deleg_msg = iq->response;
2425                 iq->dp = delegpt_from_message(iq->response, qstate->region);
2426                 if (qstate->env->cfg->qname_minimisation)
2427                         iq->minimisation_state = INIT_MINIMISE_STATE;
2428                 if(!iq->dp)
2429                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2430                 if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
2431                         qstate->region, iq->dp))
2432                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2433                 if(iq->store_parent_NS && query_dname_compare(iq->dp->name,
2434                         iq->store_parent_NS->name) == 0)
2435                         iter_merge_retry_counts(iq->dp, iq->store_parent_NS);
2436                 delegpt_log(VERB_ALGO, iq->dp);
2437                 /* Count this as a referral. */
2438                 iq->referral_count++;
2439                 iq->sent_count = 0;
2440                 /* see if the next dp is a trust anchor, or a DS was sent
2441                  * along, indicating dnssec is expected for next zone */
2442                 iq->dnssec_expected = iter_indicates_dnssec(qstate->env,
2443                         iq->dp, iq->response, iq->qchase.qclass);
2444                 /* if dnssec, validating then also fetch the key for the DS */
2445                 if(iq->dnssec_expected && qstate->env->cfg->prefetch_key &&
2446                         !(qstate->query_flags&BIT_CD))
2447                         generate_dnskey_prefetch(qstate, iq, id);
2448
2449                 /* spawn off NS and addr to auth servers for the NS we just
2450                  * got in the referral. This gets authoritative answer
2451                  * (answer section trust level) rrset.
2452                  * right after, we detach the subs, answer goes to cache. */
2453                 if(qstate->env->cfg->harden_referral_path)
2454                         generate_ns_check(qstate, iq, id);
2455
2456                 /* stop current outstanding queries.
2457                  * FIXME: should the outstanding queries be waited for and
2458                  * handled? Say by a subquery that inherits the outbound_entry.
2459                  */
2460                 outbound_list_clear(&iq->outlist);
2461                 iq->num_current_queries = 0;
2462                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2463                         qstate->env->detach_subs));
2464                 (*qstate->env->detach_subs)(qstate);
2465                 iq->num_target_queries = 0;
2466                 verbose(VERB_ALGO, "cleared outbound list for next round");
2467                 return next_state(iq, QUERYTARGETS_STATE);
2468         } else if(type == RESPONSE_TYPE_CNAME) {
2469                 uint8_t* sname = NULL;
2470                 size_t snamelen = 0;
2471                 /* CNAME type responses get a query restart (i.e., get a
2472                  * reset of the query state and go back to INIT_REQUEST_STATE).
2473                  */
2474                 verbose(VERB_DETAIL, "query response was CNAME");
2475                 if(verbosity >= VERB_ALGO)
2476                         log_dns_msg("cname msg", &iq->response->qinfo,
2477                                 iq->response->rep);
2478                 /* if qtype is DS, check we have the right level of answer,
2479                  * like grandchild answer but we need the middle, reject it */
2480                 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
2481                         && !(iq->chase_flags&BIT_RD)
2482                         && iter_ds_toolow(iq->response, iq->dp)
2483                         && iter_dp_cangodown(&iq->qchase, iq->dp)) {
2484                         outbound_list_clear(&iq->outlist);
2485                         iq->num_current_queries = 0;
2486                         fptr_ok(fptr_whitelist_modenv_detach_subs(
2487                                 qstate->env->detach_subs));
2488                         (*qstate->env->detach_subs)(qstate);
2489                         iq->num_target_queries = 0;
2490                         return processDSNSFind(qstate, iq, id);
2491                 }
2492                 /* Process the CNAME response. */
2493                 if(!handle_cname_response(qstate, iq, iq->response,
2494                         &sname, &snamelen))
2495                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2496                 /* cache the CNAME response under the current query */
2497                 /* NOTE : set referral=1, so that rrsets get stored but not
2498                  * the partial query answer (CNAME only). */
2499                 /* prefetchleeway applied because this updates answer parts */
2500                 if(!qstate->no_cache_store)
2501                         iter_dns_store(qstate->env, &iq->response->qinfo,
2502                                 iq->response->rep, 1, qstate->prefetch_leeway,
2503                                 iq->dp&&iq->dp->has_parent_side_NS, NULL,
2504                                 qstate->query_flags);
2505                 /* set the current request's qname to the new value. */
2506                 iq->qchase.qname = sname;
2507                 iq->qchase.qname_len = snamelen;
2508                 if (qstate->env->cfg->qname_minimisation)
2509                         iq->minimisation_state = INIT_MINIMISE_STATE;
2510                 /* Clear the query state, since this is a query restart. */
2511                 iq->deleg_msg = NULL;
2512                 iq->dp = NULL;
2513                 iq->dsns_point = NULL;
2514                 /* Note the query restart. */
2515                 iq->query_restart_count++;
2516                 iq->sent_count = 0;
2517
2518                 /* stop current outstanding queries.
2519                  * FIXME: should the outstanding queries be waited for and
2520                  * handled? Say by a subquery that inherits the outbound_entry.
2521                  */
2522                 outbound_list_clear(&iq->outlist);
2523                 iq->num_current_queries = 0;
2524                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2525                         qstate->env->detach_subs));
2526                 (*qstate->env->detach_subs)(qstate);
2527                 iq->num_target_queries = 0;
2528                 if(qstate->reply)
2529                         sock_list_insert(&qstate->reply_origin,
2530                                 &qstate->reply->addr, qstate->reply->addrlen,
2531                                 qstate->region);
2532                 verbose(VERB_ALGO, "cleared outbound list for query restart");
2533                 /* go to INIT_REQUEST_STATE for new qname. */
2534                 return next_state(iq, INIT_REQUEST_STATE);
2535         } else if(type == RESPONSE_TYPE_LAME) {
2536                 /* Cache the LAMEness. */
2537                 verbose(VERB_DETAIL, "query response was %sLAME",
2538                         dnsseclame?"DNSSEC ":"");
2539                 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) {
2540                         log_err("mark lame: mismatch in qname and dpname");
2541                         /* throwaway this reply below */
2542                 } else if(qstate->reply) {
2543                         /* need addr for lameness cache, but we may have
2544                          * gotten this from cache, so test to be sure */
2545                         if(!infra_set_lame(qstate->env->infra_cache,
2546                                 &qstate->reply->addr, qstate->reply->addrlen,
2547                                 iq->dp->name, iq->dp->namelen,
2548                                 *qstate->env->now, dnsseclame, 0,
2549                                 iq->qchase.qtype))
2550                                 log_err("mark host lame: out of memory");
2551                 }
2552         } else if(type == RESPONSE_TYPE_REC_LAME) {
2553                 /* Cache the LAMEness. */
2554                 verbose(VERB_DETAIL, "query response REC_LAME: "
2555                         "recursive but not authoritative server");
2556                 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) {
2557                         log_err("mark rec_lame: mismatch in qname and dpname");
2558                         /* throwaway this reply below */
2559                 } else if(qstate->reply) {
2560                         /* need addr for lameness cache, but we may have
2561                          * gotten this from cache, so test to be sure */
2562                         verbose(VERB_DETAIL, "mark as REC_LAME");
2563                         if(!infra_set_lame(qstate->env->infra_cache,
2564                                 &qstate->reply->addr, qstate->reply->addrlen,
2565                                 iq->dp->name, iq->dp->namelen,
2566                                 *qstate->env->now, 0, 1, iq->qchase.qtype))
2567                                 log_err("mark host lame: out of memory");
2568                 }
2569         } else if(type == RESPONSE_TYPE_THROWAWAY) {
2570                 /* LAME and THROWAWAY responses are handled the same way.
2571                  * In this case, the event is just sent directly back to
2572                  * the QUERYTARGETS_STATE without resetting anything,
2573                  * because, clearly, the next target must be tried. */
2574                 verbose(VERB_DETAIL, "query response was THROWAWAY");
2575         } else {
2576                 log_warn("A query response came back with an unknown type: %d",
2577                         (int)type);
2578         }
2579
2580         /* LAME, THROWAWAY and "unknown" all end up here.
2581          * Recycle to the QUERYTARGETS state to hopefully try a
2582          * different target. */
2583         if (qstate->env->cfg->qname_minimisation &&
2584                 !qstate->env->cfg->qname_minimisation_strict)
2585                 iq->minimisation_state = DONOT_MINIMISE_STATE;
2586         return next_state(iq, QUERYTARGETS_STATE);
2587 }
2588
2589 /**
2590  * Return priming query results to interested super querystates.
2591  *
2592  * Sets the delegation point and delegation message (not nonRD queries).
2593  * This is a callback from walk_supers.
2594  *
2595  * @param qstate: priming query state that finished.
2596  * @param id: module id.
2597  * @param forq: the qstate for which priming has been done.
2598  */
2599 static void
2600 prime_supers(struct module_qstate* qstate, int id, struct module_qstate* forq)
2601 {
2602         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
2603         struct delegpt* dp = NULL;
2604
2605         log_assert(qstate->is_priming || foriq->wait_priming_stub);
2606         log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR);
2607         /* Convert our response to a delegation point */
2608         dp = delegpt_from_message(qstate->return_msg, forq->region);
2609         if(!dp) {
2610                 /* if there is no convertable delegation point, then
2611                  * the ANSWER type was (presumably) a negative answer. */
2612                 verbose(VERB_ALGO, "prime response was not a positive "
2613                         "ANSWER; failing");
2614                 foriq->dp = NULL;
2615                 foriq->state = QUERYTARGETS_STATE;
2616                 return;
2617         }
2618
2619         log_query_info(VERB_DETAIL, "priming successful for", &qstate->qinfo);
2620         delegpt_log(VERB_ALGO, dp);
2621         foriq->dp = dp;
2622         foriq->deleg_msg = dns_copy_msg(qstate->return_msg, forq->region);
2623         if(!foriq->deleg_msg) {
2624                 log_err("copy prime response: out of memory");
2625                 foriq->dp = NULL;
2626                 foriq->state = QUERYTARGETS_STATE;
2627                 return;
2628         }
2629
2630         /* root priming responses go to init stage 2, priming stub
2631          * responses to to stage 3. */
2632         if(foriq->wait_priming_stub) {
2633                 foriq->state = INIT_REQUEST_3_STATE;
2634                 foriq->wait_priming_stub = 0;
2635         } else  foriq->state = INIT_REQUEST_2_STATE;
2636         /* because we are finished, the parent will be reactivated */
2637 }
2638
2639 /**
2640  * This handles the response to a priming query. This is used to handle both
2641  * root and stub priming responses. This is basically the equivalent of the
2642  * QUERY_RESP_STATE, but will not handle CNAME responses and will treat
2643  * REFERRALs as ANSWERS. It will also update and reactivate the originating
2644  * event.
2645  *
2646  * @param qstate: query state.
2647  * @param id: module id.
2648  * @return true if the event needs more immediate processing, false if not.
2649  *         This state always returns false.
2650  */
2651 static int
2652 processPrimeResponse(struct module_qstate* qstate, int id)
2653 {
2654         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
2655         enum response_type type;
2656         iq->response->rep->flags &= ~(BIT_RD|BIT_RA); /* ignore rec-lame */
2657         type = response_type_from_server(
2658                 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd),
2659                 iq->response, &iq->qchase, iq->dp);
2660         if(type == RESPONSE_TYPE_ANSWER) {
2661                 qstate->return_rcode = LDNS_RCODE_NOERROR;
2662                 qstate->return_msg = iq->response;
2663         } else {
2664                 qstate->return_rcode = LDNS_RCODE_SERVFAIL;
2665                 qstate->return_msg = NULL;
2666         }
2667
2668         /* validate the root or stub after priming (if enabled).
2669          * This is the same query as the prime query, but with validation.
2670          * Now that we are primed, the additional queries that validation
2671          * may need can be resolved, such as DLV. */
2672         if(qstate->env->cfg->harden_referral_path) {
2673                 struct module_qstate* subq = NULL;
2674                 log_nametypeclass(VERB_ALGO, "schedule prime validation",
2675                         qstate->qinfo.qname, qstate->qinfo.qtype,
2676                         qstate->qinfo.qclass);
2677                 if(!generate_sub_request(qstate->qinfo.qname,
2678                         qstate->qinfo.qname_len, qstate->qinfo.qtype,
2679                         qstate->qinfo.qclass, qstate, id, iq,
2680                         INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) {
2681                         verbose(VERB_ALGO, "could not generate prime check");
2682                 }
2683                 generate_a_aaaa_check(qstate, iq, id);
2684         }
2685
2686         /* This event is finished. */
2687         qstate->ext_state[id] = module_finished;
2688         return 0;
2689 }
2690
2691 /**
2692  * Do final processing on responses to target queries. Events reach this
2693  * state after the iterative resolution algorithm terminates. This state is
2694  * responsible for reactiving the original event, and housekeeping related
2695  * to received target responses (caching, updating the current delegation
2696  * point, etc).
2697  * Callback from walk_supers for every super state that is interested in
2698  * the results from this query.
2699  *
2700  * @param qstate: query state.
2701  * @param id: module id.
2702  * @param forq: super query state.
2703  */
2704 static void
2705 processTargetResponse(struct module_qstate* qstate, int id,
2706         struct module_qstate* forq)
2707 {
2708         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
2709         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
2710         struct ub_packed_rrset_key* rrset;
2711         struct delegpt_ns* dpns;
2712         log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR);
2713
2714         foriq->state = QUERYTARGETS_STATE;
2715         log_query_info(VERB_ALGO, "processTargetResponse", &qstate->qinfo);
2716         log_query_info(VERB_ALGO, "processTargetResponse super", &forq->qinfo);
2717
2718         /* Tell the originating event that this target query has finished
2719          * (regardless if it succeeded or not). */
2720         foriq->num_target_queries--;
2721
2722         /* check to see if parent event is still interested (in orig name).  */
2723         if(!foriq->dp) {
2724                 verbose(VERB_ALGO, "subq: parent not interested, was reset");
2725                 return; /* not interested anymore */
2726         }
2727         dpns = delegpt_find_ns(foriq->dp, qstate->qinfo.qname,
2728                         qstate->qinfo.qname_len);
2729         if(!dpns) {
2730                 /* If not interested, just stop processing this event */
2731                 verbose(VERB_ALGO, "subq: parent not interested anymore");
2732                 /* could be because parent was jostled out of the cache,
2733                    and a new identical query arrived, that does not want it*/
2734                 return;
2735         }
2736
2737         /* if iq->query_for_pside_glue then add the pside_glue (marked lame) */
2738         if(iq->pside_glue) {
2739                 /* if the pside_glue is NULL, then it could not be found,
2740                  * the done_pside is already set when created and a cache
2741                  * entry created in processFinished so nothing to do here */
2742                 log_rrset_key(VERB_ALGO, "add parentside glue to dp",
2743                         iq->pside_glue);
2744                 if(!delegpt_add_rrset(foriq->dp, forq->region,
2745                         iq->pside_glue, 1))
2746                         log_err("out of memory adding pside glue");
2747         }
2748
2749         /* This response is relevant to the current query, so we
2750          * add (attempt to add, anyway) this target(s) and reactivate
2751          * the original event.
2752          * NOTE: we could only look for the AnswerRRset if the
2753          * response type was ANSWER. */
2754         rrset = reply_find_answer_rrset(&iq->qchase, qstate->return_msg->rep);
2755         if(rrset) {
2756                 /* if CNAMEs have been followed - add new NS to delegpt. */
2757                 /* BTW. RFC 1918 says NS should not have got CNAMEs. Robust. */
2758                 if(!delegpt_find_ns(foriq->dp, rrset->rk.dname,
2759                         rrset->rk.dname_len)) {
2760                         /* if dpns->lame then set newcname ns lame too */
2761                         if(!delegpt_add_ns(foriq->dp, forq->region,
2762                                 rrset->rk.dname, dpns->lame))
2763                                 log_err("out of memory adding cnamed-ns");
2764                 }
2765                 /* if dpns->lame then set the address(es) lame too */
2766                 if(!delegpt_add_rrset(foriq->dp, forq->region, rrset,
2767                         dpns->lame))
2768                         log_err("out of memory adding targets");
2769                 verbose(VERB_ALGO, "added target response");
2770                 delegpt_log(VERB_ALGO, foriq->dp);
2771         } else {
2772                 verbose(VERB_ALGO, "iterator TargetResponse failed");
2773                 dpns->resolved = 1; /* fail the target */
2774         }
2775 }
2776
2777 /**
2778  * Process response for DS NS Find queries, that attempt to find the delegation
2779  * point where we ask the DS query from.
2780  *
2781  * @param qstate: query state.
2782  * @param id: module id.
2783  * @param forq: super query state.
2784  */
2785 static void
2786 processDSNSResponse(struct module_qstate* qstate, int id,
2787         struct module_qstate* forq)
2788 {
2789         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
2790
2791         /* if the finished (iq->response) query has no NS set: continue
2792          * up to look for the right dp; nothing to change, do DPNSstate */
2793         if(qstate->return_rcode != LDNS_RCODE_NOERROR)
2794                 return; /* seek further */
2795         /* find the NS RRset (without allowing CNAMEs) */
2796         if(!reply_find_rrset(qstate->return_msg->rep, qstate->qinfo.qname,
2797                 qstate->qinfo.qname_len, LDNS_RR_TYPE_NS,
2798                 qstate->qinfo.qclass)){
2799                 return; /* seek further */
2800         }
2801
2802         /* else, store as DP and continue at querytargets */
2803         foriq->state = QUERYTARGETS_STATE;
2804         foriq->dp = delegpt_from_message(qstate->return_msg, forq->region);
2805         if(!foriq->dp) {
2806                 log_err("out of memory in dsns dp alloc");
2807                 return; /* dp==NULL in QUERYTARGETS makes SERVFAIL */
2808         }
2809         /* success, go query the querytargets in the new dp (and go down) */
2810 }
2811
2812 /**
2813  * Process response for qclass=ANY queries for a particular class.
2814  * Append to result or error-exit.
2815  *
2816  * @param qstate: query state.
2817  * @param id: module id.
2818  * @param forq: super query state.
2819  */
2820 static void
2821 processClassResponse(struct module_qstate* qstate, int id,
2822         struct module_qstate* forq)
2823 {
2824         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
2825         struct dns_msg* from = qstate->return_msg;
2826         log_query_info(VERB_ALGO, "processClassResponse", &qstate->qinfo);
2827         log_query_info(VERB_ALGO, "processClassResponse super", &forq->qinfo);
2828         if(qstate->return_rcode != LDNS_RCODE_NOERROR) {
2829                 /* cause servfail for qclass ANY query */
2830                 foriq->response = NULL;
2831                 foriq->state = FINISHED_STATE;
2832                 return;
2833         }
2834         /* append result */
2835         if(!foriq->response) {
2836                 /* allocate the response: copy RCODE, sec_state */
2837                 foriq->response = dns_copy_msg(from, forq->region);
2838                 if(!foriq->response) {
2839                         log_err("malloc failed for qclass ANY response");
2840                         foriq->state = FINISHED_STATE;
2841                         return;
2842                 }
2843                 foriq->response->qinfo.qclass = forq->qinfo.qclass;
2844                 /* qclass ANY does not receive the AA flag on replies */
2845                 foriq->response->rep->authoritative = 0;
2846         } else {
2847                 struct dns_msg* to = foriq->response;
2848                 /* add _from_ this response _to_ existing collection */
2849                 /* if there are records, copy RCODE */
2850                 /* lower sec_state if this message is lower */
2851                 if(from->rep->rrset_count != 0) {
2852                         size_t n = from->rep->rrset_count+to->rep->rrset_count;
2853                         struct ub_packed_rrset_key** dest, **d;
2854                         /* copy appropriate rcode */
2855                         to->rep->flags = from->rep->flags;
2856                         /* copy rrsets */
2857                         if(from->rep->rrset_count > RR_COUNT_MAX ||
2858                                 to->rep->rrset_count > RR_COUNT_MAX) {
2859                                 log_err("malloc failed (too many rrsets) in collect ANY");
2860                                 foriq->state = FINISHED_STATE;
2861                                 return; /* integer overflow protection */
2862                         }
2863                         dest = regional_alloc(forq->region, sizeof(dest[0])*n);
2864                         if(!dest) {
2865                                 log_err("malloc failed in collect ANY");
2866                                 foriq->state = FINISHED_STATE;
2867                                 return;
2868                         }
2869                         d = dest;
2870                         /* copy AN */
2871                         memcpy(dest, to->rep->rrsets, to->rep->an_numrrsets
2872                                 * sizeof(dest[0]));
2873                         dest += to->rep->an_numrrsets;
2874                         memcpy(dest, from->rep->rrsets, from->rep->an_numrrsets
2875                                 * sizeof(dest[0]));
2876                         dest += from->rep->an_numrrsets;
2877                         /* copy NS */
2878                         memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets,
2879                                 to->rep->ns_numrrsets * sizeof(dest[0]));
2880                         dest += to->rep->ns_numrrsets;
2881                         memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets,
2882                                 from->rep->ns_numrrsets * sizeof(dest[0]));
2883                         dest += from->rep->ns_numrrsets;
2884                         /* copy AR */
2885                         memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets+
2886                                 to->rep->ns_numrrsets,
2887                                 to->rep->ar_numrrsets * sizeof(dest[0]));
2888                         dest += to->rep->ar_numrrsets;
2889                         memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets+
2890                                 from->rep->ns_numrrsets,
2891                                 from->rep->ar_numrrsets * sizeof(dest[0]));
2892                         /* update counts */
2893                         to->rep->rrsets = d;
2894                         to->rep->an_numrrsets += from->rep->an_numrrsets;
2895                         to->rep->ns_numrrsets += from->rep->ns_numrrsets;
2896                         to->rep->ar_numrrsets += from->rep->ar_numrrsets;
2897                         to->rep->rrset_count = n;
2898                 }
2899                 if(from->rep->security < to->rep->security) /* lowest sec */
2900                         to->rep->security = from->rep->security;
2901                 if(from->rep->qdcount != 0) /* insert qd if appropriate */
2902                         to->rep->qdcount = from->rep->qdcount;
2903                 if(from->rep->ttl < to->rep->ttl) /* use smallest TTL */
2904                         to->rep->ttl = from->rep->ttl;
2905                 if(from->rep->prefetch_ttl < to->rep->prefetch_ttl)
2906                         to->rep->prefetch_ttl = from->rep->prefetch_ttl;
2907         }
2908         /* are we done? */
2909         foriq->num_current_queries --;
2910         if(foriq->num_current_queries == 0)
2911                 foriq->state = FINISHED_STATE;
2912 }
2913
2914 /**
2915  * Collect class ANY responses and make them into one response.  This
2916  * state is started and it creates queries for all classes (that have
2917  * root hints).  The answers are then collected.
2918  *
2919  * @param qstate: query state.
2920  * @param id: module id.
2921  * @return true if the event needs more immediate processing, false if not.
2922  */
2923 static int
2924 processCollectClass(struct module_qstate* qstate, int id)
2925 {
2926         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
2927         struct module_qstate* subq;
2928         /* If qchase.qclass == 0 then send out queries for all classes.
2929          * Otherwise, do nothing (wait for all answers to arrive and the
2930          * processClassResponse to put them together, and that moves us
2931          * towards the Finished state when done. */
2932         if(iq->qchase.qclass == 0) {
2933                 uint16_t c = 0;
2934                 iq->qchase.qclass = LDNS_RR_CLASS_ANY;
2935                 while(iter_get_next_root(qstate->env->hints,
2936                         qstate->env->fwds, &c)) {
2937                         /* generate query for this class */
2938                         log_nametypeclass(VERB_ALGO, "spawn collect query",
2939                                 qstate->qinfo.qname, qstate->qinfo.qtype, c);
2940                         if(!generate_sub_request(qstate->qinfo.qname,
2941                                 qstate->qinfo.qname_len, qstate->qinfo.qtype,
2942                                 c, qstate, id, iq, INIT_REQUEST_STATE,
2943                                 FINISHED_STATE, &subq,
2944                                 (int)!(qstate->query_flags&BIT_CD))) {
2945                                 return error_response(qstate, id,
2946                                         LDNS_RCODE_SERVFAIL);
2947                         }
2948                         /* ignore subq, no special init required */
2949                         iq->num_current_queries ++;
2950                         if(c == 0xffff)
2951                                 break;
2952                         else c++;
2953                 }
2954                 /* if no roots are configured at all, return */
2955                 if(iq->num_current_queries == 0) {
2956                         verbose(VERB_ALGO, "No root hints or fwds, giving up "
2957                                 "on qclass ANY");
2958                         return error_response(qstate, id, LDNS_RCODE_REFUSED);
2959                 }
2960                 /* return false, wait for queries to return */
2961         }
2962         /* if woke up here because of an answer, wait for more answers */
2963         return 0;
2964 }
2965
2966 /**
2967  * This handles the final state for first-tier responses (i.e., responses to
2968  * externally generated queries).
2969  *
2970  * @param qstate: query state.
2971  * @param iq: iterator query state.
2972  * @param id: module id.
2973  * @return true if the event needs more processing, false if not. Since this
2974  *         is the final state for an event, it always returns false.
2975  */
2976 static int
2977 processFinished(struct module_qstate* qstate, struct iter_qstate* iq,
2978         int id)
2979 {
2980         log_query_info(VERB_QUERY, "finishing processing for",
2981                 &qstate->qinfo);
2982
2983         /* store negative cache element for parent side glue. */
2984         if(!qstate->no_cache_store && iq->query_for_pside_glue
2985                 && !iq->pside_glue)
2986                         iter_store_parentside_neg(qstate->env, &qstate->qinfo,
2987                                 iq->deleg_msg?iq->deleg_msg->rep:
2988                                 (iq->response?iq->response->rep:NULL));
2989         if(!iq->response) {
2990                 verbose(VERB_ALGO, "No response is set, servfail");
2991                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2992         }
2993
2994         /* Make sure that the RA flag is set (since the presence of
2995          * this module means that recursion is available) */
2996         iq->response->rep->flags |= BIT_RA;
2997
2998         /* Clear the AA flag */
2999         /* FIXME: does this action go here or in some other module? */
3000         iq->response->rep->flags &= ~BIT_AA;
3001
3002         /* make sure QR flag is on */
3003         iq->response->rep->flags |= BIT_QR;
3004
3005         /* we have finished processing this query */
3006         qstate->ext_state[id] = module_finished;
3007
3008         /* TODO:  we are using a private TTL, trim the response. */
3009         /* if (mPrivateTTL > 0){IterUtils.setPrivateTTL(resp, mPrivateTTL); } */
3010
3011         /* prepend any items we have accumulated */
3012         if(iq->an_prepend_list || iq->ns_prepend_list) {
3013                 if(!iter_prepend(iq, iq->response, qstate->region)) {
3014                         log_err("prepend rrsets: out of memory");
3015                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3016                 }
3017                 /* reset the query name back */
3018                 iq->response->qinfo = qstate->qinfo;
3019                 /* the security state depends on the combination */
3020                 iq->response->rep->security = sec_status_unchecked;
3021                 /* store message with the finished prepended items,
3022                  * but only if we did recursion. The nonrecursion referral
3023                  * from cache does not need to be stored in the msg cache. */
3024                 if(!qstate->no_cache_store && qstate->query_flags&BIT_RD) {
3025                         iter_dns_store(qstate->env, &qstate->qinfo,
3026                                 iq->response->rep, 0, qstate->prefetch_leeway,
3027                                 iq->dp&&iq->dp->has_parent_side_NS,
3028                                 qstate->region, qstate->query_flags);
3029                 }
3030         }
3031         qstate->return_rcode = LDNS_RCODE_NOERROR;
3032         qstate->return_msg = iq->response;
3033         return 0;
3034 }
3035
3036 /*
3037  * Return priming query results to interestes super querystates.
3038  *
3039  * Sets the delegation point and delegation message (not nonRD queries).
3040  * This is a callback from walk_supers.
3041  *
3042  * @param qstate: query state that finished.
3043  * @param id: module id.
3044  * @param super: the qstate to inform.
3045  */
3046 void
3047 iter_inform_super(struct module_qstate* qstate, int id,
3048         struct module_qstate* super)
3049 {
3050         if(!qstate->is_priming && super->qinfo.qclass == LDNS_RR_CLASS_ANY)
3051                 processClassResponse(qstate, id, super);
3052         else if(super->qinfo.qtype == LDNS_RR_TYPE_DS && ((struct iter_qstate*)
3053                 super->minfo[id])->state == DSNS_FIND_STATE)
3054                 processDSNSResponse(qstate, id, super);
3055         else if(qstate->return_rcode != LDNS_RCODE_NOERROR)
3056                 error_supers(qstate, id, super);
3057         else if(qstate->is_priming)
3058                 prime_supers(qstate, id, super);
3059         else    processTargetResponse(qstate, id, super);
3060 }
3061
3062 /**
3063  * Handle iterator state.
3064  * Handle events. This is the real processing loop for events, responsible
3065  * for moving events through the various states. If a processing method
3066  * returns true, then it will be advanced to the next state. If false, then
3067  * processing will stop.
3068  *
3069  * @param qstate: query state.
3070  * @param ie: iterator shared global environment.
3071  * @param iq: iterator query state.
3072  * @param id: module id.
3073  */
3074 static void
3075 iter_handle(struct module_qstate* qstate, struct iter_qstate* iq,
3076         struct iter_env* ie, int id)
3077 {
3078         int cont = 1;
3079         while(cont) {
3080                 verbose(VERB_ALGO, "iter_handle processing q with state %s",
3081                         iter_state_to_string(iq->state));
3082                 switch(iq->state) {
3083                         case INIT_REQUEST_STATE:
3084                                 cont = processInitRequest(qstate, iq, ie, id);
3085                                 break;
3086                         case INIT_REQUEST_2_STATE:
3087                                 cont = processInitRequest2(qstate, iq, id);
3088                                 break;
3089                         case INIT_REQUEST_3_STATE:
3090                                 cont = processInitRequest3(qstate, iq, id);
3091                                 break;
3092                         case QUERYTARGETS_STATE:
3093                                 cont = processQueryTargets(qstate, iq, ie, id);
3094                                 break;
3095                         case QUERY_RESP_STATE:
3096                                 cont = processQueryResponse(qstate, iq, id);
3097                                 break;
3098                         case PRIME_RESP_STATE:
3099                                 cont = processPrimeResponse(qstate, id);
3100                                 break;
3101                         case COLLECT_CLASS_STATE:
3102                                 cont = processCollectClass(qstate, id);
3103                                 break;
3104                         case DSNS_FIND_STATE:
3105                                 cont = processDSNSFind(qstate, iq, id);
3106                                 break;
3107                         case FINISHED_STATE:
3108                                 cont = processFinished(qstate, iq, id);
3109                                 break;
3110                         default:
3111                                 log_warn("iterator: invalid state: %d",
3112                                         iq->state);
3113                                 cont = 0;
3114                                 break;
3115                 }
3116         }
3117 }
3118
3119 /**
3120  * This is the primary entry point for processing request events. Note that
3121  * this method should only be used by external modules.
3122  * @param qstate: query state.
3123  * @param ie: iterator shared global environment.
3124  * @param iq: iterator query state.
3125  * @param id: module id.
3126  */
3127 static void
3128 process_request(struct module_qstate* qstate, struct iter_qstate* iq,
3129         struct iter_env* ie, int id)
3130 {
3131         /* external requests start in the INIT state, and finish using the
3132          * FINISHED state. */
3133         iq->state = INIT_REQUEST_STATE;
3134         iq->final_state = FINISHED_STATE;
3135         verbose(VERB_ALGO, "process_request: new external request event");
3136         iter_handle(qstate, iq, ie, id);
3137 }
3138
3139 /** process authoritative server reply */
3140 static void
3141 process_response(struct module_qstate* qstate, struct iter_qstate* iq,
3142         struct iter_env* ie, int id, struct outbound_entry* outbound,
3143         enum module_ev event)
3144 {
3145         struct msg_parse* prs;
3146         struct edns_data edns;
3147         sldns_buffer* pkt;
3148
3149         verbose(VERB_ALGO, "process_response: new external response event");
3150         iq->response = NULL;
3151         iq->state = QUERY_RESP_STATE;
3152         if(event == module_event_noreply || event == module_event_error) {
3153                 if(event == module_event_noreply && iq->sent_count >= 3 &&
3154                         qstate->env->cfg->use_caps_bits_for_id &&
3155                         !iq->caps_fallback) {
3156                         /* start fallback */
3157                         iq->caps_fallback = 1;
3158                         iq->caps_server = 0;
3159                         iq->caps_reply = NULL;
3160                         iq->caps_response = NULL;
3161                         iq->state = QUERYTARGETS_STATE;
3162                         iq->num_current_queries--;
3163                         /* need fresh attempts for the 0x20 fallback, if
3164                          * that was the cause for the failure */
3165                         iter_dec_attempts(iq->dp, 3);
3166                         verbose(VERB_DETAIL, "Capsforid: timeouts, starting fallback");
3167                         goto handle_it;
3168                 }
3169                 goto handle_it;
3170         }
3171         if( (event != module_event_reply && event != module_event_capsfail)
3172                 || !qstate->reply) {
3173                 log_err("Bad event combined with response");
3174                 outbound_list_remove(&iq->outlist, outbound);
3175                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3176                 return;
3177         }
3178
3179         /* parse message */
3180         prs = (struct msg_parse*)regional_alloc(qstate->env->scratch,
3181                 sizeof(struct msg_parse));
3182         if(!prs) {
3183                 log_err("out of memory on incoming message");
3184                 /* like packet got dropped */
3185                 goto handle_it;
3186         }
3187         memset(prs, 0, sizeof(*prs));
3188         memset(&edns, 0, sizeof(edns));
3189         pkt = qstate->reply->c->buffer;
3190         sldns_buffer_set_position(pkt, 0);
3191         if(parse_packet(pkt, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) {
3192                 verbose(VERB_ALGO, "parse error on reply packet");
3193                 goto handle_it;
3194         }
3195         /* edns is not examined, but removed from message to help cache */
3196         if(parse_extract_edns(prs, &edns, qstate->env->scratch) !=
3197                 LDNS_RCODE_NOERROR)
3198                 goto handle_it;
3199
3200         /* Copy the edns options we may got from the back end */
3201         if(edns.opt_list) {
3202                 qstate->edns_opts_back_in = edns_opt_copy_region(edns.opt_list,
3203                         qstate->region);
3204                 if(!qstate->edns_opts_back_in) {
3205                         log_err("out of memory on incoming message");
3206                         /* like packet got dropped */
3207                         goto handle_it;
3208                 }
3209                 if(!inplace_cb_edns_back_parsed_call(qstate->env, qstate)) {
3210                         log_err("unable to call edns_back_parsed callback");
3211                         goto handle_it;
3212                 }
3213         }
3214
3215         /* remove CD-bit, we asked for in case we handle validation ourself */
3216         prs->flags &= ~BIT_CD;
3217
3218         /* normalize and sanitize: easy to delete items from linked lists */
3219         if(!scrub_message(pkt, prs, &iq->qinfo_out, iq->dp->name,
3220                 qstate->env->scratch, qstate->env, ie)) {
3221                 /* if 0x20 enabled, start fallback, but we have no message */
3222                 if(event == module_event_capsfail && !iq->caps_fallback) {
3223                         iq->caps_fallback = 1;
3224                         iq->caps_server = 0;
3225                         iq->caps_reply = NULL;
3226                         iq->caps_response = NULL;
3227                         iq->state = QUERYTARGETS_STATE;
3228                         iq->num_current_queries--;
3229                         verbose(VERB_DETAIL, "Capsforid: scrub failed, starting fallback with no response");
3230                 }
3231                 goto handle_it;
3232         }
3233
3234         /* allocate response dns_msg in region */
3235         iq->response = dns_alloc_msg(pkt, prs, qstate->region);
3236         if(!iq->response)
3237                 goto handle_it;
3238         log_query_info(VERB_DETAIL, "response for", &qstate->qinfo);
3239         log_name_addr(VERB_DETAIL, "reply from", iq->dp->name,
3240                 &qstate->reply->addr, qstate->reply->addrlen);
3241         if(verbosity >= VERB_ALGO)
3242                 log_dns_msg("incoming scrubbed packet:", &iq->response->qinfo,
3243                         iq->response->rep);
3244
3245         if(event == module_event_capsfail || iq->caps_fallback) {
3246                 /* for fallback we care about main answer, not additionals */
3247                 /* removing that makes comparison more likely to succeed */
3248                 caps_strip_reply(iq->response->rep);
3249                 if(!iq->caps_fallback) {
3250                         /* start fallback */
3251                         iq->caps_fallback = 1;
3252                         iq->caps_server = 0;
3253                         iq->caps_reply = iq->response->rep;
3254                         iq->caps_response = iq->response;
3255                         iq->state = QUERYTARGETS_STATE;
3256                         iq->num_current_queries--;
3257                         verbose(VERB_DETAIL, "Capsforid: starting fallback");
3258                         goto handle_it;
3259                 } else {
3260                         /* check if reply is the same, otherwise, fail */
3261                         if(!iq->caps_reply) {
3262                                 iq->caps_reply = iq->response->rep;
3263                                 iq->caps_response = iq->response;
3264                                 iq->caps_server = -1; /*become zero at ++,
3265                                 so that we start the full set of trials */
3266                         } else if(caps_failed_rcode(iq->caps_reply) &&
3267                                 !caps_failed_rcode(iq->response->rep)) {
3268                                 /* prefer to upgrade to non-SERVFAIL */
3269                                 iq->caps_reply = iq->response->rep;
3270                                 iq->caps_response = iq->response;
3271                         } else if(!caps_failed_rcode(iq->caps_reply) &&
3272                                 caps_failed_rcode(iq->response->rep)) {
3273                                 /* if we have non-SERVFAIL as answer then
3274                                  * we can ignore SERVFAILs for the equality
3275                                  * comparison */
3276                                 /* no instructions here, skip other else */
3277                         } else if(caps_failed_rcode(iq->caps_reply) &&
3278                                 caps_failed_rcode(iq->response->rep)) {
3279                                 /* failure is same as other failure in fallbk*/
3280                                 /* no instructions here, skip other else */
3281                         } else if(!reply_equal(iq->response->rep, iq->caps_reply,
3282                                 qstate->env->scratch)) {
3283                                 verbose(VERB_DETAIL, "Capsforid fallback: "
3284                                         "getting different replies, failed");
3285                                 outbound_list_remove(&iq->outlist, outbound);
3286                                 (void)error_response(qstate, id,
3287                                         LDNS_RCODE_SERVFAIL);
3288                                 return;
3289                         }
3290                         /* continue the fallback procedure at next server */
3291                         iq->caps_server++;
3292                         iq->state = QUERYTARGETS_STATE;
3293                         iq->num_current_queries--;
3294                         verbose(VERB_DETAIL, "Capsforid: reply is equal. "
3295                                 "go to next fallback");
3296                         goto handle_it;
3297                 }
3298         }
3299         iq->caps_fallback = 0; /* if we were in fallback, 0x20 is OK now */
3300
3301 handle_it:
3302         outbound_list_remove(&iq->outlist, outbound);
3303         iter_handle(qstate, iq, ie, id);
3304 }
3305
3306 void
3307 iter_operate(struct module_qstate* qstate, enum module_ev event, int id,
3308         struct outbound_entry* outbound)
3309 {
3310         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
3311         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3312         verbose(VERB_QUERY, "iterator[module %d] operate: extstate:%s event:%s",
3313                 id, strextstate(qstate->ext_state[id]), strmodulevent(event));
3314         if(iq) log_query_info(VERB_QUERY, "iterator operate: query",
3315                 &qstate->qinfo);
3316         if(iq && qstate->qinfo.qname != iq->qchase.qname)
3317                 log_query_info(VERB_QUERY, "iterator operate: chased to",
3318                         &iq->qchase);
3319
3320         /* perform iterator state machine */
3321         if((event == module_event_new || event == module_event_pass) &&
3322                 iq == NULL) {
3323                 if(!iter_new(qstate, id)) {
3324                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3325                         return;
3326                 }
3327                 iq = (struct iter_qstate*)qstate->minfo[id];
3328                 process_request(qstate, iq, ie, id);
3329                 return;
3330         }
3331         if(iq && event == module_event_pass) {
3332                 iter_handle(qstate, iq, ie, id);
3333                 return;
3334         }
3335         if(iq && outbound) {
3336                 process_response(qstate, iq, ie, id, outbound, event);
3337                 return;
3338         }
3339         if(event == module_event_error) {
3340                 verbose(VERB_ALGO, "got called with event error, giving up");
3341                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3342                 return;
3343         }
3344
3345         log_err("bad event for iterator");
3346         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3347 }
3348
3349 void
3350 iter_clear(struct module_qstate* qstate, int id)
3351 {
3352         struct iter_qstate* iq;
3353         if(!qstate)
3354                 return;
3355         iq = (struct iter_qstate*)qstate->minfo[id];
3356         if(iq) {
3357                 outbound_list_clear(&iq->outlist);
3358                 if(iq->target_count && --iq->target_count[0] == 0)
3359                         free(iq->target_count);
3360                 iq->num_current_queries = 0;
3361         }
3362         qstate->minfo[id] = NULL;
3363 }
3364
3365 size_t
3366 iter_get_mem(struct module_env* env, int id)
3367 {
3368         struct iter_env* ie = (struct iter_env*)env->modinfo[id];
3369         if(!ie)
3370                 return 0;
3371         return sizeof(*ie) + sizeof(int)*((size_t)ie->max_dependency_depth+1)
3372                 + donotq_get_mem(ie->donotq) + priv_get_mem(ie->priv);
3373 }
3374
3375 /**
3376  * The iterator function block
3377  */
3378 static struct module_func_block iter_block = {
3379         "iterator",
3380         &iter_init, &iter_deinit, &iter_operate, &iter_inform_super,
3381         &iter_clear, &iter_get_mem
3382 };
3383
3384 struct module_func_block*
3385 iter_get_funcblock(void)
3386 {
3387         return &iter_block;
3388 }
3389
3390 const char*
3391 iter_state_to_string(enum iter_state state)
3392 {
3393         switch (state)
3394         {
3395         case INIT_REQUEST_STATE :
3396                 return "INIT REQUEST STATE";
3397         case INIT_REQUEST_2_STATE :
3398                 return "INIT REQUEST STATE (stage 2)";
3399         case INIT_REQUEST_3_STATE:
3400                 return "INIT REQUEST STATE (stage 3)";
3401         case QUERYTARGETS_STATE :
3402                 return "QUERY TARGETS STATE";
3403         case PRIME_RESP_STATE :
3404                 return "PRIME RESPONSE STATE";
3405         case COLLECT_CLASS_STATE :
3406                 return "COLLECT CLASS STATE";
3407         case DSNS_FIND_STATE :
3408                 return "DSNS FIND STATE";
3409         case QUERY_RESP_STATE :
3410                 return "QUERY RESPONSE STATE";
3411         case FINISHED_STATE :
3412                 return "FINISHED RESPONSE STATE";
3413         default :
3414                 return "UNKNOWN ITER STATE";
3415         }
3416 }
3417
3418 int
3419 iter_state_is_responsestate(enum iter_state s)
3420 {
3421         switch(s) {
3422                 case INIT_REQUEST_STATE :
3423                 case INIT_REQUEST_2_STATE :
3424                 case INIT_REQUEST_3_STATE :
3425                 case QUERYTARGETS_STATE :
3426                 case COLLECT_CLASS_STATE :
3427                         return 0;
3428                 default:
3429                         break;
3430         }
3431         return 1;
3432 }