contrib/unbound/iterator/iterator.c

   1 /*
   2  * iterator/iterator.c - iterative resolver DNS query response module
   3  *
   4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
   5  *
   6  * This software is open source.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * Redistributions of source code must retain the above copyright notice,
  13  * this list of conditions and the following disclaimer.
  14  *
  15  * Redistributions in binary form must reproduce the above copyright notice,
  16  * this list of conditions and the following disclaimer in the documentation
  17  * and/or other materials provided with the distribution.
  18  *
  19  * Neither the name of the NLNET LABS nor the names of its contributors may
  20  * be used to endorse or promote products derived from this software without
  21  * specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 /**
  37  * \file
  38  *
  39  * This file contains a module that performs recursive iterative DNS query
  40  * processing.
  41  */
  42
  43 #include "config.h"
  44 #include "iterator/iterator.h"
  45 #include "iterator/iter_utils.h"
  46 #include "iterator/iter_hints.h"
  47 #include "iterator/iter_fwd.h"
  48 #include "iterator/iter_donotq.h"
  49 #include "iterator/iter_delegpt.h"
  50 #include "iterator/iter_resptype.h"
  51 #include "iterator/iter_scrub.h"
  52 #include "iterator/iter_priv.h"
  53 #include "validator/val_neg.h"
  54 #include "services/cache/dns.h"
  55 #include "services/cache/infra.h"
  56 #include "services/authzone.h"
  57 #include "util/module.h"
  58 #include "util/netevent.h"
  59 #include "util/net_help.h"
  60 #include "util/regional.h"
  61 #include "util/data/dname.h"
  62 #include "util/data/msgencode.h"
  63 #include "util/fptr_wlist.h"
  64 #include "util/config_file.h"
  65 #include "util/random.h"
  66 #include "sldns/rrdef.h"
  67 #include "sldns/wire2str.h"
  68 #include "sldns/str2wire.h"
  69 #include "sldns/parseutil.h"
  70 #include "sldns/sbuffer.h"
  71
  72 int
  73 iter_init(struct module_env* env, int id)
  74 {
  75         struct iter_env* iter_env = (struct iter_env*)calloc(1,
  76                 sizeof(struct iter_env));
  77         if(!iter_env) {
  78                 log_err("malloc failure");
  79                 return 0;
  80         }
  81         env->modinfo[id] = (void*)iter_env;
  82
  83         lock_basic_init(&iter_env->queries_ratelimit_lock);
  84         lock_protect(&iter_env->queries_ratelimit_lock,
  85                         &iter_env->num_queries_ratelimited,
  86                 sizeof(iter_env->num_queries_ratelimited));
  87
  88         if(!iter_apply_cfg(iter_env, env->cfg)) {
  89                 log_err("iterator: could not apply configuration settings.");
  90                 return 0;
  91         }
  92
  93         return 1;
  94 }
  95
  96 /** delete caps_whitelist element */
  97 static void
  98 caps_free(struct rbnode_type* n, void* ATTR_UNUSED(d))
  99 {
 100         if(n) {
 101                 free(((struct name_tree_node*)n)->name);
 102                 free(n);
 103         }
 104 }
 105
 106 void
 107 iter_deinit(struct module_env* env, int id)
 108 {
 109         struct iter_env* iter_env;
 110         if(!env || !env->modinfo[id])
 111                 return;
 112         iter_env = (struct iter_env*)env->modinfo[id];
 113         lock_basic_destroy(&iter_env->queries_ratelimit_lock);
 114         free(iter_env->target_fetch_policy);
 115         priv_delete(iter_env->priv);
 116         donotq_delete(iter_env->donotq);
 117         if(iter_env->caps_white) {
 118                 traverse_postorder(iter_env->caps_white, caps_free, NULL);
 119                 free(iter_env->caps_white);
 120         }
 121         free(iter_env);
 122         env->modinfo[id] = NULL;
 123 }
 124
 125 /** new query for iterator */
 126 static int
 127 iter_new(struct module_qstate* qstate, int id)
 128 {
 129         struct iter_qstate* iq = (struct iter_qstate*)regional_alloc(
 130                 qstate->region, sizeof(struct iter_qstate));
 131         qstate->minfo[id] = iq;
 132         if(!iq)
 133                 return 0;
 134         memset(iq, 0, sizeof(*iq));
 135         iq->state = INIT_REQUEST_STATE;
 136         iq->final_state = FINISHED_STATE;
 137         iq->an_prepend_list = NULL;
 138         iq->an_prepend_last = NULL;
 139         iq->ns_prepend_list = NULL;
 140         iq->ns_prepend_last = NULL;
 141         iq->dp = NULL;
 142         iq->depth = 0;
 143         iq->num_target_queries = 0;
 144         iq->num_current_queries = 0;
 145         iq->query_restart_count = 0;
 146         iq->referral_count = 0;
 147         iq->sent_count = 0;
 148         iq->ratelimit_ok = 0;
 149         iq->target_count = NULL;
 150         iq->wait_priming_stub = 0;
 151         iq->refetch_glue = 0;
 152         iq->dnssec_expected = 0;
 153         iq->dnssec_lame_query = 0;
 154         iq->chase_flags = qstate->query_flags;
 155         /* Start with the (current) qname. */
 156         iq->qchase = qstate->qinfo;
 157         outbound_list_init(&iq->outlist);
 158         iq->minimise_count = 0;
 159         iq->minimise_timeout_count = 0;
 160         if (qstate->env->cfg->qname_minimisation)
 161                 iq->minimisation_state = INIT_MINIMISE_STATE;
 162         else
 163                 iq->minimisation_state = DONOT_MINIMISE_STATE;
 164
 165         memset(&iq->qinfo_out, 0, sizeof(struct query_info));
 166         return 1;
 167 }
 168
 169 /**
 170  * Transition to the next state. This can be used to advance a currently
 171  * processing event. It cannot be used to reactivate a forEvent.
 172  *
 173  * @param iq: iterator query state
 174  * @param nextstate The state to transition to.
 175  * @return true. This is so this can be called as the return value for the
 176  *         actual process*State() methods. (Transitioning to the next state
 177  *         implies further processing).
 178  */
 179 static int
 180 next_state(struct iter_qstate* iq, enum iter_state nextstate)
 181 {
 182         /* If transitioning to a "response" state, make sure that there is a
 183          * response */
 184         if(iter_state_is_responsestate(nextstate)) {
 185                 if(iq->response == NULL) {
 186                         log_err("transitioning to response state sans "
 187                                 "response.");
 188                 }
 189         }
 190         iq->state = nextstate;
 191         return 1;
 192 }
 193
 194 /**
 195  * Transition an event to its final state. Final states always either return
 196  * a result up the module chain, or reactivate a dependent event. Which
 197  * final state to transition to is set in the module state for the event when
 198  * it was created, and depends on the original purpose of the event.
 199  *
 200  * The response is stored in the qstate->buf buffer.
 201  *
 202  * @param iq: iterator query state
 203  * @return false. This is so this method can be used as the return value for
 204  *         the processState methods. (Transitioning to the final state
 205  */
 206 static int
 207 final_state(struct iter_qstate* iq)
 208 {
 209         return next_state(iq, iq->final_state);
 210 }
 211
 212 /**
 213  * Callback routine to handle errors in parent query states
 214  * @param qstate: query state that failed.
 215  * @param id: module id.
 216  * @param super: super state.
 217  */
 218 static void
 219 error_supers(struct module_qstate* qstate, int id, struct module_qstate* super)
 220 {
 221         struct iter_qstate* super_iq = (struct iter_qstate*)super->minfo[id];
 222
 223         if(qstate->qinfo.qtype == LDNS_RR_TYPE_A ||
 224                 qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA) {
 225                 /* mark address as failed. */
 226                 struct delegpt_ns* dpns = NULL;
 227                 super_iq->num_target_queries--;
 228                 if(super_iq->dp)
 229                         dpns = delegpt_find_ns(super_iq->dp,
 230                                 qstate->qinfo.qname, qstate->qinfo.qname_len);
 231                 if(!dpns) {
 232                         /* not interested */
 233                         verbose(VERB_ALGO, "subq error, but not interested");
 234                         log_query_info(VERB_ALGO, "superq", &super->qinfo);
 235                         if(super_iq->dp)
 236                                 delegpt_log(VERB_ALGO, super_iq->dp);
 237                         log_assert(0);
 238                         return;
 239                 } else {
 240                         /* see if the failure did get (parent-lame) info */
 241                         if(!cache_fill_missing(super->env, super_iq->qchase.qclass,
 242                                 super->region, super_iq->dp))
 243                                 log_err("out of memory adding missing");
 244                 }
 245                 dpns->resolved = 1; /* mark as failed */
 246         }
 247         if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS) {
 248                 /* prime failed to get delegation */
 249                 super_iq->dp = NULL;
 250         }
 251         /* evaluate targets again */
 252         super_iq->state = QUERYTARGETS_STATE;
 253         /* super becomes runnable, and will process this change */
 254 }
 255
 256 /**
 257  * Return an error to the client
 258  * @param qstate: our query state
 259  * @param id: module id
 260  * @param rcode: error code (DNS errcode).
 261  * @return: 0 for use by caller, to make notation easy, like:
 262  *      return error_response(..).
 263  */
 264 static int
 265 error_response(struct module_qstate* qstate, int id, int rcode)
 266 {
 267         verbose(VERB_QUERY, "return error response %s",
 268                 sldns_lookup_by_id(sldns_rcodes, rcode)?
 269                 sldns_lookup_by_id(sldns_rcodes, rcode)->name:"??");
 270         qstate->return_rcode = rcode;
 271         qstate->return_msg = NULL;
 272         qstate->ext_state[id] = module_finished;
 273         return 0;
 274 }
 275
 276 /**
 277  * Return an error to the client and cache the error code in the
 278  * message cache (so per qname, qtype, qclass).
 279  * @param qstate: our query state
 280  * @param id: module id
 281  * @param rcode: error code (DNS errcode).
 282  * @return: 0 for use by caller, to make notation easy, like:
 283  *      return error_response(..).
 284  */
 285 static int
 286 error_response_cache(struct module_qstate* qstate, int id, int rcode)
 287 {
 288         if(!qstate->no_cache_store) {
 289                 /* store in cache */
 290                 struct reply_info err;
 291                 if(qstate->prefetch_leeway > NORR_TTL) {
 292                         verbose(VERB_ALGO, "error response for prefetch in cache");
 293                         /* attempt to adjust the cache entry prefetch */
 294                         if(dns_cache_prefetch_adjust(qstate->env, &qstate->qinfo,
 295                                 NORR_TTL, qstate->query_flags))
 296                                 return error_response(qstate, id, rcode);
 297                         /* if that fails (not in cache), fall through to store err */
 298                 }
 299                 if(qstate->env->cfg->serve_expired) {
 300                         /* if serving expired contents, and such content is
 301                          * already available, don't overwrite this servfail */
 302                         struct msgreply_entry* msg;
 303                         if((msg=msg_cache_lookup(qstate->env,
 304                                 qstate->qinfo.qname, qstate->qinfo.qname_len,
 305                                 qstate->qinfo.qtype, qstate->qinfo.qclass,
 306                                 qstate->query_flags, 0, 0))
 307                                 != NULL) {
 308                                 lock_rw_unlock(&msg->entry.lock);
 309                                 return error_response(qstate, id, rcode);
 310                         }
 311                         /* serving expired contents, but nothing is cached
 312                          * at all, so the servfail cache entry is useful
 313                          * (stops waste of time on this servfail NORR_TTL) */
 314                 }
 315                 memset(&err, 0, sizeof(err));
 316                 err.flags = (uint16_t)(BIT_QR | BIT_RA);
 317                 FLAGS_SET_RCODE(err.flags, rcode);
 318                 err.qdcount = 1;
 319                 err.ttl = NORR_TTL;
 320                 err.prefetch_ttl = PREFETCH_TTL_CALC(err.ttl);
 321                 /* do not waste time trying to validate this servfail */
 322                 err.security = sec_status_indeterminate;
 323                 verbose(VERB_ALGO, "store error response in message cache");
 324                 iter_dns_store(qstate->env, &qstate->qinfo, &err, 0, 0, 0, NULL,
 325                         qstate->query_flags);
 326         }
 327         return error_response(qstate, id, rcode);
 328 }
 329
 330 /** check if prepend item is duplicate item */
 331 static int
 332 prepend_is_duplicate(struct ub_packed_rrset_key** sets, size_t to,
 333         struct ub_packed_rrset_key* dup)
 334 {
 335         size_t i;
 336         for(i=0; i<to; i++) {
 337                 if(sets[i]->rk.type == dup->rk.type &&
 338                         sets[i]->rk.rrset_class == dup->rk.rrset_class &&
 339                         sets[i]->rk.dname_len == dup->rk.dname_len &&
 340                         query_dname_compare(sets[i]->rk.dname, dup->rk.dname)
 341                         == 0)
 342                         return 1;
 343         }
 344         return 0;
 345 }
 346
 347 /** prepend the prepend list in the answer and authority section of dns_msg */
 348 static int
 349 iter_prepend(struct iter_qstate* iq, struct dns_msg* msg,
 350         struct regional* region)
 351 {
 352         struct iter_prep_list* p;
 353         struct ub_packed_rrset_key** sets;
 354         size_t num_an = 0, num_ns = 0;;
 355         for(p = iq->an_prepend_list; p; p = p->next)
 356                 num_an++;
 357         for(p = iq->ns_prepend_list; p; p = p->next)
 358                 num_ns++;
 359         if(num_an + num_ns == 0)
 360                 return 1;
 361         verbose(VERB_ALGO, "prepending %d rrsets", (int)num_an + (int)num_ns);
 362         if(num_an > RR_COUNT_MAX || num_ns > RR_COUNT_MAX ||
 363                 msg->rep->rrset_count > RR_COUNT_MAX) return 0; /* overflow */
 364         sets = regional_alloc(region, (num_an+num_ns+msg->rep->rrset_count) *
 365                 sizeof(struct ub_packed_rrset_key*));
 366         if(!sets)
 367                 return 0;
 368         /* ANSWER section */
 369         num_an = 0;
 370         for(p = iq->an_prepend_list; p; p = p->next) {
 371                 sets[num_an++] = p->rrset;
 372         }
 373         memcpy(sets+num_an, msg->rep->rrsets, msg->rep->an_numrrsets *
 374                 sizeof(struct ub_packed_rrset_key*));
 375         /* AUTH section */
 376         num_ns = 0;
 377         for(p = iq->ns_prepend_list; p; p = p->next) {
 378                 if(prepend_is_duplicate(sets+msg->rep->an_numrrsets+num_an,
 379                         num_ns, p->rrset) || prepend_is_duplicate(
 380                         msg->rep->rrsets+msg->rep->an_numrrsets,
 381                         msg->rep->ns_numrrsets, p->rrset))
 382                         continue;
 383                 sets[msg->rep->an_numrrsets + num_an + num_ns++] = p->rrset;
 384         }
 385         memcpy(sets + num_an + msg->rep->an_numrrsets + num_ns,
 386                 msg->rep->rrsets + msg->rep->an_numrrsets,
 387                 (msg->rep->ns_numrrsets + msg->rep->ar_numrrsets) *
 388                 sizeof(struct ub_packed_rrset_key*));
 389
 390         /* NXDOMAIN rcode can stay if we prepended DNAME/CNAMEs, because
 391          * this is what recursors should give. */
 392         msg->rep->rrset_count += num_an + num_ns;
 393         msg->rep->an_numrrsets += num_an;
 394         msg->rep->ns_numrrsets += num_ns;
 395         msg->rep->rrsets = sets;
 396         return 1;
 397 }
 398
 399 /**
 400  * Find rrset in ANSWER prepend list.
 401  * to avoid duplicate DNAMEs when a DNAME is traversed twice.
 402  * @param iq: iterator query state.
 403  * @param rrset: rrset to add.
 404  * @return false if not found
 405  */
 406 static int
 407 iter_find_rrset_in_prepend_answer(struct iter_qstate* iq,
 408         struct ub_packed_rrset_key* rrset)
 409 {
 410         struct iter_prep_list* p = iq->an_prepend_list;
 411         while(p) {
 412                 if(ub_rrset_compare(p->rrset, rrset) == 0 &&
 413                         rrsetdata_equal((struct packed_rrset_data*)p->rrset
 414                         ->entry.data, (struct packed_rrset_data*)rrset
 415                         ->entry.data))
 416                         return 1;
 417                 p = p->next;
 418         }
 419         return 0;
 420 }
 421
 422 /**
 423  * Add rrset to ANSWER prepend list
 424  * @param qstate: query state.
 425  * @param iq: iterator query state.
 426  * @param rrset: rrset to add.
 427  * @return false on failure (malloc).
 428  */
 429 static int
 430 iter_add_prepend_answer(struct module_qstate* qstate, struct iter_qstate* iq,
 431         struct ub_packed_rrset_key* rrset)
 432 {
 433         struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc(
 434                 qstate->region, sizeof(struct iter_prep_list));
 435         if(!p)
 436                 return 0;
 437         p->rrset = rrset;
 438         p->next = NULL;
 439         /* add at end */
 440         if(iq->an_prepend_last)
 441                 iq->an_prepend_last->next = p;
 442         else    iq->an_prepend_list = p;
 443         iq->an_prepend_last = p;
 444         return 1;
 445 }
 446
 447 /**
 448  * Add rrset to AUTHORITY prepend list
 449  * @param qstate: query state.
 450  * @param iq: iterator query state.
 451  * @param rrset: rrset to add.
 452  * @return false on failure (malloc).
 453  */
 454 static int
 455 iter_add_prepend_auth(struct module_qstate* qstate, struct iter_qstate* iq,
 456         struct ub_packed_rrset_key* rrset)
 457 {
 458         struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc(
 459                 qstate->region, sizeof(struct iter_prep_list));
 460         if(!p)
 461                 return 0;
 462         p->rrset = rrset;
 463         p->next = NULL;
 464         /* add at end */
 465         if(iq->ns_prepend_last)
 466                 iq->ns_prepend_last->next = p;
 467         else    iq->ns_prepend_list = p;
 468         iq->ns_prepend_last = p;
 469         return 1;
 470 }
 471
 472 /**
 473  * Given a CNAME response (defined as a response containing a CNAME or DNAME
 474  * that does not answer the request), process the response, modifying the
 475  * state as necessary. This follows the CNAME/DNAME chain and returns the
 476  * final query name.
 477  *
 478  * sets the new query name, after following the CNAME/DNAME chain.
 479  * @param qstate: query state.
 480  * @param iq: iterator query state.
 481  * @param msg: the response.
 482  * @param mname: returned target new query name.
 483  * @param mname_len: length of mname.
 484  * @return false on (malloc) error.
 485  */
 486 static int
 487 handle_cname_response(struct module_qstate* qstate, struct iter_qstate* iq,
 488         struct dns_msg* msg, uint8_t** mname, size_t* mname_len)
 489 {
 490         size_t i;
 491         /* Start with the (current) qname. */
 492         *mname = iq->qchase.qname;
 493         *mname_len = iq->qchase.qname_len;
 494
 495         /* Iterate over the ANSWER rrsets in order, looking for CNAMEs and
 496          * DNAMES. */
 497         for(i=0; i<msg->rep->an_numrrsets; i++) {
 498                 struct ub_packed_rrset_key* r = msg->rep->rrsets[i];
 499                 /* If there is a (relevant) DNAME, add it to the list.
 500                  * We always expect there to be CNAME that was generated
 501                  * by this DNAME following, so we don't process the DNAME
 502                  * directly.  */
 503                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_DNAME &&
 504                         dname_strict_subdomain_c(*mname, r->rk.dname) &&
 505                         !iter_find_rrset_in_prepend_answer(iq, r)) {
 506                         if(!iter_add_prepend_answer(qstate, iq, r))
 507                                 return 0;
 508                         continue;
 509                 }
 510
 511                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_CNAME &&
 512                         query_dname_compare(*mname, r->rk.dname) == 0 &&
 513                         !iter_find_rrset_in_prepend_answer(iq, r)) {
 514                         /* Add this relevant CNAME rrset to the prepend list.*/
 515                         if(!iter_add_prepend_answer(qstate, iq, r))
 516                                 return 0;
 517                         get_cname_target(r, mname, mname_len);
 518                 }
 519
 520                 /* Other rrsets in the section are ignored. */
 521         }
 522         /* add authority rrsets to authority prepend, for wildcarded CNAMEs */
 523         for(i=msg->rep->an_numrrsets; i<msg->rep->an_numrrsets +
 524                 msg->rep->ns_numrrsets; i++) {
 525                 struct ub_packed_rrset_key* r = msg->rep->rrsets[i];
 526                 /* only add NSEC/NSEC3, as they may be needed for validation */
 527                 if(ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC ||
 528                         ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC3) {
 529                         if(!iter_add_prepend_auth(qstate, iq, r))
 530                                 return 0;
 531                 }
 532         }
 533         return 1;
 534 }
 535
 536 /** see if last resort is possible - does config allow queries to parent */
 537 static int
 538 can_have_last_resort(struct module_env* env, uint8_t* nm, size_t nmlen,
 539         uint16_t qclass, struct delegpt** retdp)
 540 {
 541         struct delegpt* fwddp;
 542         struct iter_hints_stub* stub;
 543         int labs = dname_count_labels(nm);
 544         /* do not process a last resort (the parent side) if a stub
 545          * or forward is configured, because we do not want to go 'above'
 546          * the configured servers */
 547         if(!dname_is_root(nm) && (stub = (struct iter_hints_stub*)
 548                 name_tree_find(&env->hints->tree, nm, nmlen, labs, qclass)) &&
 549                 /* has_parent side is turned off for stub_first, where we
 550                  * are allowed to go to the parent */
 551                 stub->dp->has_parent_side_NS) {
 552                 if(retdp) *retdp = stub->dp;
 553                 return 0;
 554         }
 555         if((fwddp = forwards_find(env->fwds, nm, qclass)) &&
 556                 /* has_parent_side is turned off for forward_first, where
 557                  * we are allowed to go to the parent */
 558                 fwddp->has_parent_side_NS) {
 559                 if(retdp) *retdp = fwddp;
 560                 return 0;
 561         }
 562         return 1;
 563 }
 564
 565 /** see if target name is caps-for-id whitelisted */
 566 static int
 567 is_caps_whitelisted(struct iter_env* ie, struct iter_qstate* iq)
 568 {
 569         if(!ie->caps_white) return 0; /* no whitelist, or no capsforid */
 570         return name_tree_lookup(ie->caps_white, iq->qchase.qname,
 571                 iq->qchase.qname_len, dname_count_labels(iq->qchase.qname),
 572                 iq->qchase.qclass) != NULL;
 573 }
 574
 575 /** create target count structure for this query */
 576 static void
 577 target_count_create(struct iter_qstate* iq)
 578 {
 579         if(!iq->target_count) {
 580                 iq->target_count = (int*)calloc(2, sizeof(int));
 581                 /* if calloc fails we simply do not track this number */
 582                 if(iq->target_count)
 583                         iq->target_count[0] = 1;
 584         }
 585 }
 586
 587 static void
 588 target_count_increase(struct iter_qstate* iq, int num)
 589 {
 590         target_count_create(iq);
 591         if(iq->target_count)
 592                 iq->target_count[1] += num;
 593 }
 594
 595 /**
 596  * Generate a subrequest.
 597  * Generate a local request event. Local events are tied to this module, and
 598  * have a corresponding (first tier) event that is waiting for this event to
 599  * resolve to continue.
 600  *
 601  * @param qname The query name for this request.
 602  * @param qnamelen length of qname
 603  * @param qtype The query type for this request.
 604  * @param qclass The query class for this request.
 605  * @param qstate The event that is generating this event.
 606  * @param id: module id.
 607  * @param iq: The iterator state that is generating this event.
 608  * @param initial_state The initial response state (normally this
 609  *          is QUERY_RESP_STATE, unless it is known that the request won't
 610  *          need iterative processing
 611  * @param finalstate The final state for the response to this request.
 612  * @param subq_ret: if newly allocated, the subquerystate, or NULL if it does
 613  *      not need initialisation.
 614  * @param v: if true, validation is done on the subquery.
 615  * @return false on error (malloc).
 616  */
 617 static int
 618 generate_sub_request(uint8_t* qname, size_t qnamelen, uint16_t qtype,
 619         uint16_t qclass, struct module_qstate* qstate, int id,
 620         struct iter_qstate* iq, enum iter_state initial_state,
 621         enum iter_state finalstate, struct module_qstate** subq_ret, int v)
 622 {
 623         struct module_qstate* subq = NULL;
 624         struct iter_qstate* subiq = NULL;
 625         uint16_t qflags = 0; /* OPCODE QUERY, no flags */
 626         struct query_info qinf;
 627         int prime = (finalstate == PRIME_RESP_STATE)?1:0;
 628         int valrec = 0;
 629         qinf.qname = qname;
 630         qinf.qname_len = qnamelen;
 631         qinf.qtype = qtype;
 632         qinf.qclass = qclass;
 633         qinf.local_alias = NULL;
 634
 635         /* RD should be set only when sending the query back through the INIT
 636          * state. */
 637         if(initial_state == INIT_REQUEST_STATE)
 638                 qflags |= BIT_RD;
 639         /* We set the CD flag so we can send this through the "head" of
 640          * the resolution chain, which might have a validator. We are
 641          * uninterested in validating things not on the direct resolution
 642          * path.  */
 643         if(!v) {
 644                 qflags |= BIT_CD;
 645                 valrec = 1;
 646         }
 647
 648         /* attach subquery, lookup existing or make a new one */
 649         fptr_ok(fptr_whitelist_modenv_attach_sub(qstate->env->attach_sub));
 650         if(!(*qstate->env->attach_sub)(qstate, &qinf, qflags, prime, valrec,
 651                 &subq)) {
 652                 return 0;
 653         }
 654         *subq_ret = subq;
 655         if(subq) {
 656                 /* initialise the new subquery */
 657                 subq->curmod = id;
 658                 subq->ext_state[id] = module_state_initial;
 659                 subq->minfo[id] = regional_alloc(subq->region,
 660                         sizeof(struct iter_qstate));
 661                 if(!subq->minfo[id]) {
 662                         log_err("init subq: out of memory");
 663                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 664                                 qstate->env->kill_sub));
 665                         (*qstate->env->kill_sub)(subq);
 666                         return 0;
 667                 }
 668                 subiq = (struct iter_qstate*)subq->minfo[id];
 669                 memset(subiq, 0, sizeof(*subiq));
 670                 subiq->num_target_queries = 0;
 671                 target_count_create(iq);
 672                 subiq->target_count = iq->target_count;
 673                 if(iq->target_count)
 674                         iq->target_count[0] ++; /* extra reference */
 675                 subiq->num_current_queries = 0;
 676                 subiq->depth = iq->depth+1;
 677                 outbound_list_init(&subiq->outlist);
 678                 subiq->state = initial_state;
 679                 subiq->final_state = finalstate;
 680                 subiq->qchase = subq->qinfo;
 681                 subiq->chase_flags = subq->query_flags;
 682                 subiq->refetch_glue = 0;
 683                 if(qstate->env->cfg->qname_minimisation)
 684                         subiq->minimisation_state = INIT_MINIMISE_STATE;
 685                 else
 686                         subiq->minimisation_state = DONOT_MINIMISE_STATE;
 687                 memset(&subiq->qinfo_out, 0, sizeof(struct query_info));
 688         }
 689         return 1;
 690 }
 691
 692 /**
 693  * Generate and send a root priming request.
 694  * @param qstate: the qtstate that triggered the need to prime.
 695  * @param iq: iterator query state.
 696  * @param id: module id.
 697  * @param qclass: the class to prime.
 698  * @return 0 on failure
 699  */
 700 static int
 701 prime_root(struct module_qstate* qstate, struct iter_qstate* iq, int id,
 702         uint16_t qclass)
 703 {
 704         struct delegpt* dp;
 705         struct module_qstate* subq;
 706         verbose(VERB_DETAIL, "priming . %s NS",
 707                 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)?
 708                 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)->name:"??");
 709         dp = hints_lookup_root(qstate->env->hints, qclass);
 710         if(!dp) {
 711                 verbose(VERB_ALGO, "Cannot prime due to lack of hints");
 712                 return 0;
 713         }
 714         /* Priming requests start at the QUERYTARGETS state, skipping
 715          * the normal INIT state logic (which would cause an infloop). */
 716         if(!generate_sub_request((uint8_t*)"\000", 1, LDNS_RR_TYPE_NS,
 717                 qclass, qstate, id, iq, QUERYTARGETS_STATE, PRIME_RESP_STATE,
 718                 &subq, 0)) {
 719                 verbose(VERB_ALGO, "could not prime root");
 720                 return 0;
 721         }
 722         if(subq) {
 723                 struct iter_qstate* subiq =
 724                         (struct iter_qstate*)subq->minfo[id];
 725                 /* Set the initial delegation point to the hint.
 726                  * copy dp, it is now part of the root prime query.
 727                  * dp was part of in the fixed hints structure. */
 728                 subiq->dp = delegpt_copy(dp, subq->region);
 729                 if(!subiq->dp) {
 730                         log_err("out of memory priming root, copydp");
 731                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 732                                 qstate->env->kill_sub));
 733                         (*qstate->env->kill_sub)(subq);
 734                         return 0;
 735                 }
 736                 /* there should not be any target queries. */
 737                 subiq->num_target_queries = 0;
 738                 subiq->dnssec_expected = iter_indicates_dnssec(
 739                         qstate->env, subiq->dp, NULL, subq->qinfo.qclass);
 740         }
 741
 742         /* this module stops, our submodule starts, and does the query. */
 743         qstate->ext_state[id] = module_wait_subquery;
 744         return 1;
 745 }
 746
 747 /**
 748  * Generate and process a stub priming request. This method tests for the
 749  * need to prime a stub zone, so it is safe to call for every request.
 750  *
 751  * @param qstate: the qtstate that triggered the need to prime.
 752  * @param iq: iterator query state.
 753  * @param id: module id.
 754  * @param qname: request name.
 755  * @param qclass: request class.
 756  * @return true if a priming subrequest was made, false if not. The will only
 757  *         issue a priming request if it detects an unprimed stub.
 758  *         Uses value of 2 to signal during stub-prime in root-prime situation
 759  *         that a noprime-stub is available and resolution can continue.
 760  */
 761 static int
 762 prime_stub(struct module_qstate* qstate, struct iter_qstate* iq, int id,
 763         uint8_t* qname, uint16_t qclass)
 764 {
 765         /* Lookup the stub hint. This will return null if the stub doesn't
 766          * need to be re-primed. */
 767         struct iter_hints_stub* stub;
 768         struct delegpt* stub_dp;
 769         struct module_qstate* subq;
 770
 771         if(!qname) return 0;
 772         stub = hints_lookup_stub(qstate->env->hints, qname, qclass, iq->dp);
 773         /* The stub (if there is one) does not need priming. */
 774         if(!stub)
 775                 return 0;
 776         stub_dp = stub->dp;
 777         /* if we have an auth_zone dp, and stub is equal, don't prime stub
 778          * yet, unless we want to fallback and avoid the auth_zone */
 779         if(!iq->auth_zone_avoid && iq->dp && iq->dp->auth_dp &&
 780                 query_dname_compare(iq->dp->name, stub_dp->name) == 0)
 781                 return 0;
 782
 783         /* is it a noprime stub (always use) */
 784         if(stub->noprime) {
 785                 int r = 0;
 786                 if(iq->dp == NULL) r = 2;
 787                 /* copy the dp out of the fixed hints structure, so that
 788                  * it can be changed when servicing this query */
 789                 iq->dp = delegpt_copy(stub_dp, qstate->region);
 790                 if(!iq->dp) {
 791                         log_err("out of memory priming stub");
 792                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 793                         return 1; /* return 1 to make module stop, with error */
 794                 }
 795                 log_nametypeclass(VERB_DETAIL, "use stub", stub_dp->name,
 796                         LDNS_RR_TYPE_NS, qclass);
 797                 return r;
 798         }
 799
 800         /* Otherwise, we need to (re)prime the stub. */
 801         log_nametypeclass(VERB_DETAIL, "priming stub", stub_dp->name,
 802                 LDNS_RR_TYPE_NS, qclass);
 803
 804         /* Stub priming events start at the QUERYTARGETS state to avoid the
 805          * redundant INIT state processing. */
 806         if(!generate_sub_request(stub_dp->name, stub_dp->namelen,
 807                 LDNS_RR_TYPE_NS, qclass, qstate, id, iq,
 808                 QUERYTARGETS_STATE, PRIME_RESP_STATE, &subq, 0)) {
 809                 verbose(VERB_ALGO, "could not prime stub");
 810                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 811                 return 1; /* return 1 to make module stop, with error */
 812         }
 813         if(subq) {
 814                 struct iter_qstate* subiq =
 815                         (struct iter_qstate*)subq->minfo[id];
 816
 817                 /* Set the initial delegation point to the hint. */
 818                 /* make copy to avoid use of stub dp by different qs/threads */
 819                 subiq->dp = delegpt_copy(stub_dp, subq->region);
 820                 if(!subiq->dp) {
 821                         log_err("out of memory priming stub, copydp");
 822                         fptr_ok(fptr_whitelist_modenv_kill_sub(
 823                                 qstate->env->kill_sub));
 824                         (*qstate->env->kill_sub)(subq);
 825                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 826                         return 1; /* return 1 to make module stop, with error */
 827                 }
 828                 /* there should not be any target queries -- although there
 829                  * wouldn't be anyway, since stub hints never have
 830                  * missing targets. */
 831                 subiq->num_target_queries = 0;
 832                 subiq->wait_priming_stub = 1;
 833                 subiq->dnssec_expected = iter_indicates_dnssec(
 834                         qstate->env, subiq->dp, NULL, subq->qinfo.qclass);
 835         }
 836
 837         /* this module stops, our submodule starts, and does the query. */
 838         qstate->ext_state[id] = module_wait_subquery;
 839         return 1;
 840 }
 841
 842 /**
 843  * Generate a delegation point for an auth zone (unless cached dp is better)
 844  * false on alloc failure.
 845  */
 846 static int
 847 auth_zone_delegpt(struct module_qstate* qstate, struct iter_qstate* iq,
 848         uint8_t* delname, size_t delnamelen)
 849 {
 850         struct auth_zone* z;
 851         if(iq->auth_zone_avoid)
 852                 return 1;
 853         if(!delname) {
 854                 delname = iq->qchase.qname;
 855                 delnamelen = iq->qchase.qname_len;
 856         }
 857         lock_rw_rdlock(&qstate->env->auth_zones->lock);
 858         z = auth_zones_find_zone(qstate->env->auth_zones, delname, delnamelen,
 859                 qstate->qinfo.qclass);
 860         if(!z) {
 861                 lock_rw_unlock(&qstate->env->auth_zones->lock);
 862                 return 1;
 863         }
 864         lock_rw_rdlock(&z->lock);
 865         lock_rw_unlock(&qstate->env->auth_zones->lock);
 866         if(z->for_upstream) {
 867                 if(iq->dp && query_dname_compare(z->name, iq->dp->name) == 0
 868                         && iq->dp->auth_dp && qstate->blacklist &&
 869                         z->fallback_enabled) {
 870                         /* cache is blacklisted and fallback, and we
 871                          * already have an auth_zone dp */
 872                         if(verbosity>=VERB_ALGO) {
 873                                 char buf[255+1];
 874                                 dname_str(z->name, buf);
 875                                 verbose(VERB_ALGO, "auth_zone %s "
 876                                   "fallback because cache blacklisted",
 877                                   buf);
 878                         }
 879                         lock_rw_unlock(&z->lock);
 880                         iq->dp = NULL;
 881                         return 1;
 882                 }
 883                 if(iq->dp==NULL || dname_subdomain_c(z->name, iq->dp->name)) {
 884                         struct delegpt* dp;
 885                         if(qstate->blacklist && z->fallback_enabled) {
 886                                 /* cache is blacklisted because of a DNSSEC
 887                                  * validation failure, and the zone allows
 888                                  * fallback to the internet, query there. */
 889                                 if(verbosity>=VERB_ALGO) {
 890                                         char buf[255+1];
 891                                         dname_str(z->name, buf);
 892                                         verbose(VERB_ALGO, "auth_zone %s "
 893                                           "fallback because cache blacklisted",
 894                                           buf);
 895                                 }
 896                                 lock_rw_unlock(&z->lock);
 897                                 return 1;
 898                         }
 899                         dp = (struct delegpt*)regional_alloc_zero(
 900                                 qstate->region, sizeof(*dp));
 901                         if(!dp) {
 902                                 log_err("alloc failure");
 903                                 if(z->fallback_enabled) {
 904                                         lock_rw_unlock(&z->lock);
 905                                         return 1; /* just fallback */
 906                                 }
 907                                 lock_rw_unlock(&z->lock);
 908                                 return 0;
 909                         }
 910                         dp->name = regional_alloc_init(qstate->region,
 911                                 z->name, z->namelen);
 912                         if(!dp->name) {
 913                                 log_err("alloc failure");
 914                                 if(z->fallback_enabled) {
 915                                         lock_rw_unlock(&z->lock);
 916                                         return 1; /* just fallback */
 917                                 }
 918                                 lock_rw_unlock(&z->lock);
 919                                 return 0;
 920                         }
 921                         dp->namelen = z->namelen;
 922                         dp->namelabs = z->namelabs;
 923                         dp->auth_dp = 1;
 924                         iq->dp = dp;
 925                 }
 926         }
 927
 928         lock_rw_unlock(&z->lock);
 929         return 1;
 930 }
 931
 932 /**
 933  * Generate A and AAAA checks for glue that is in-zone for the referral
 934  * we just got to obtain authoritative information on the addresses.
 935  *
 936  * @param qstate: the qtstate that triggered the need to prime.
 937  * @param iq: iterator query state.
 938  * @param id: module id.
 939  */
 940 static void
 941 generate_a_aaaa_check(struct module_qstate* qstate, struct iter_qstate* iq,
 942         int id)
 943 {
 944         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
 945         struct module_qstate* subq;
 946         size_t i;
 947         struct reply_info* rep = iq->response->rep;
 948         struct ub_packed_rrset_key* s;
 949         log_assert(iq->dp);
 950
 951         if(iq->depth == ie->max_dependency_depth)
 952                 return;
 953         /* walk through additional, and check if in-zone,
 954          * only relevant A, AAAA are left after scrub anyway */
 955         for(i=rep->an_numrrsets+rep->ns_numrrsets; i<rep->rrset_count; i++) {
 956                 s = rep->rrsets[i];
 957                 /* check *ALL* addresses that are transmitted in additional*/
 958                 /* is it an address ? */
 959                 if( !(ntohs(s->rk.type)==LDNS_RR_TYPE_A ||
 960                         ntohs(s->rk.type)==LDNS_RR_TYPE_AAAA)) {
 961                         continue;
 962                 }
 963                 /* is this query the same as the A/AAAA check for it */
 964                 if(qstate->qinfo.qtype == ntohs(s->rk.type) &&
 965                         qstate->qinfo.qclass == ntohs(s->rk.rrset_class) &&
 966                         query_dname_compare(qstate->qinfo.qname,
 967                                 s->rk.dname)==0 &&
 968                         (qstate->query_flags&BIT_RD) &&
 969                         !(qstate->query_flags&BIT_CD))
 970                         continue;
 971
 972                 /* generate subrequest for it */
 973                 log_nametypeclass(VERB_ALGO, "schedule addr fetch",
 974                         s->rk.dname, ntohs(s->rk.type),
 975                         ntohs(s->rk.rrset_class));
 976                 if(!generate_sub_request(s->rk.dname, s->rk.dname_len,
 977                         ntohs(s->rk.type), ntohs(s->rk.rrset_class),
 978                         qstate, id, iq,
 979                         INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) {
 980                         verbose(VERB_ALGO, "could not generate addr check");
 981                         return;
 982                 }
 983                 /* ignore subq - not need for more init */
 984         }
 985 }
 986
 987 /**
 988  * Generate a NS check request to obtain authoritative information
 989  * on an NS rrset.
 990  *
 991  * @param qstate: the qtstate that triggered the need to prime.
 992  * @param iq: iterator query state.
 993  * @param id: module id.
 994  */
 995 static void
 996 generate_ns_check(struct module_qstate* qstate, struct iter_qstate* iq, int id)
 997 {
 998         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
 999         struct module_qstate* subq;
1000         log_assert(iq->dp);
1001
1002         if(iq->depth == ie->max_dependency_depth)
1003                 return;
1004         if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen,
1005                 iq->qchase.qclass, NULL))
1006                 return;
1007         /* is this query the same as the nscheck? */
1008         if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS &&
1009                 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 &&
1010                 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){
1011                 /* spawn off A, AAAA queries for in-zone glue to check */
1012                 generate_a_aaaa_check(qstate, iq, id);
1013                 return;
1014         }
1015         /* no need to get the NS record for DS, it is above the zonecut */
1016         if(qstate->qinfo.qtype == LDNS_RR_TYPE_DS)
1017                 return;
1018
1019         log_nametypeclass(VERB_ALGO, "schedule ns fetch",
1020                 iq->dp->name, LDNS_RR_TYPE_NS, iq->qchase.qclass);
1021         if(!generate_sub_request(iq->dp->name, iq->dp->namelen,
1022                 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
1023                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) {
1024                 verbose(VERB_ALGO, "could not generate ns check");
1025                 return;
1026         }
1027         if(subq) {
1028                 struct iter_qstate* subiq =
1029                         (struct iter_qstate*)subq->minfo[id];
1030
1031                 /* make copy to avoid use of stub dp by different qs/threads */
1032                 /* refetch glue to start higher up the tree */
1033                 subiq->refetch_glue = 1;
1034                 subiq->dp = delegpt_copy(iq->dp, subq->region);
1035                 if(!subiq->dp) {
1036                         log_err("out of memory generating ns check, copydp");
1037                         fptr_ok(fptr_whitelist_modenv_kill_sub(
1038                                 qstate->env->kill_sub));
1039                         (*qstate->env->kill_sub)(subq);
1040                         return;
1041                 }
1042         }
1043 }
1044
1045 /**
1046  * Generate a DNSKEY prefetch query to get the DNSKEY for the DS record we
1047  * just got in a referral (where we have dnssec_expected, thus have trust
1048  * anchors above it).  Note that right after calling this routine the
1049  * iterator detached subqueries (because of following the referral), and thus
1050  * the DNSKEY query becomes detached, its return stored in the cache for
1051  * later lookup by the validator.  This cache lookup by the validator avoids
1052  * the roundtrip incurred by the DNSKEY query.  The DNSKEY query is now
1053  * performed at about the same time the original query is sent to the domain,
1054  * thus the two answers are likely to be returned at about the same time,
1055  * saving a roundtrip from the validated lookup.
1056  *
1057  * @param qstate: the qtstate that triggered the need to prime.
1058  * @param iq: iterator query state.
1059  * @param id: module id.
1060  */
1061 static void
1062 generate_dnskey_prefetch(struct module_qstate* qstate,
1063         struct iter_qstate* iq, int id)
1064 {
1065         struct module_qstate* subq;
1066         log_assert(iq->dp);
1067
1068         /* is this query the same as the prefetch? */
1069         if(qstate->qinfo.qtype == LDNS_RR_TYPE_DNSKEY &&
1070                 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 &&
1071                 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){
1072                 return;
1073         }
1074
1075         /* if the DNSKEY is in the cache this lookup will stop quickly */
1076         log_nametypeclass(VERB_ALGO, "schedule dnskey prefetch",
1077                 iq->dp->name, LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass);
1078         if(!generate_sub_request(iq->dp->name, iq->dp->namelen,
1079                 LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass, qstate, id, iq,
1080                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0)) {
1081                 /* we'll be slower, but it'll work */
1082                 verbose(VERB_ALGO, "could not generate dnskey prefetch");
1083                 return;
1084         }
1085         if(subq) {
1086                 struct iter_qstate* subiq =
1087                         (struct iter_qstate*)subq->minfo[id];
1088                 /* this qstate has the right delegation for the dnskey lookup*/
1089                 /* make copy to avoid use of stub dp by different qs/threads */
1090                 subiq->dp = delegpt_copy(iq->dp, subq->region);
1091                 /* if !subiq->dp, it'll start from the cache, no problem */
1092         }
1093 }
1094
1095 /**
1096  * See if the query needs forwarding.
1097  *
1098  * @param qstate: query state.
1099  * @param iq: iterator query state.
1100  * @return true if the request is forwarded, false if not.
1101  *      If returns true but, iq->dp is NULL then a malloc failure occurred.
1102  */
1103 static int
1104 forward_request(struct module_qstate* qstate, struct iter_qstate* iq)
1105 {
1106         struct delegpt* dp;
1107         uint8_t* delname = iq->qchase.qname;
1108         size_t delnamelen = iq->qchase.qname_len;
1109         if(iq->refetch_glue) {
1110                 delname = iq->dp->name;
1111                 delnamelen = iq->dp->namelen;
1112         }
1113         /* strip one label off of DS query to lookup higher for it */
1114         if( (iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue)
1115                 && !dname_is_root(iq->qchase.qname))
1116                 dname_remove_label(&delname, &delnamelen);
1117         dp = forwards_lookup(qstate->env->fwds, delname, iq->qchase.qclass);
1118         if(!dp)
1119                 return 0;
1120         /* send recursion desired to forward addr */
1121         iq->chase_flags |= BIT_RD;
1122         iq->dp = delegpt_copy(dp, qstate->region);
1123         /* iq->dp checked by caller */
1124         verbose(VERB_ALGO, "forwarding request");
1125         return 1;
1126 }
1127
1128 /**
1129  * Process the initial part of the request handling. This state roughly
1130  * corresponds to resolver algorithms steps 1 (find answer in cache) and 2
1131  * (find the best servers to ask).
1132  *
1133  * Note that all requests start here, and query restarts revisit this state.
1134  *
1135  * This state either generates: 1) a response, from cache or error, 2) a
1136  * priming event, or 3) forwards the request to the next state (init2,
1137  * generally).
1138  *
1139  * @param qstate: query state.
1140  * @param iq: iterator query state.
1141  * @param ie: iterator shared global environment.
1142  * @param id: module id.
1143  * @return true if the event needs more request processing immediately,
1144  *         false if not.
1145  */
1146 static int
1147 processInitRequest(struct module_qstate* qstate, struct iter_qstate* iq,
1148         struct iter_env* ie, int id)
1149 {
1150         uint8_t* delname;
1151         size_t delnamelen;
1152         struct dns_msg* msg = NULL;
1153
1154         log_query_info(VERB_DETAIL, "resolving", &qstate->qinfo);
1155         /* check effort */
1156
1157         /* We enforce a maximum number of query restarts. This is primarily a
1158          * cheap way to prevent CNAME loops. */
1159         if(iq->query_restart_count > MAX_RESTART_COUNT) {
1160                 verbose(VERB_QUERY, "request has exceeded the maximum number"
1161                         " of query restarts with %d", iq->query_restart_count);
1162                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1163         }
1164
1165         /* We enforce a maximum recursion/dependency depth -- in general,
1166          * this is unnecessary for dependency loops (although it will
1167          * catch those), but it provides a sensible limit to the amount
1168          * of work required to answer a given query. */
1169         verbose(VERB_ALGO, "request has dependency depth of %d", iq->depth);
1170         if(iq->depth > ie->max_dependency_depth) {
1171                 verbose(VERB_QUERY, "request has exceeded the maximum "
1172                         "dependency depth with depth of %d", iq->depth);
1173                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1174         }
1175
1176         /* If the request is qclass=ANY, setup to generate each class */
1177         if(qstate->qinfo.qclass == LDNS_RR_CLASS_ANY) {
1178                 iq->qchase.qclass = 0;
1179                 return next_state(iq, COLLECT_CLASS_STATE);
1180         }
1181
1182         /*
1183          * If we are restricted by a forward-zone or a stub-zone, we
1184          * can't re-fetch glue for this delegation point.
1185          * we won’t try to re-fetch glue if the iq->dp is null.
1186          */
1187         if (iq->refetch_glue &&
1188                 iq->dp &&
1189                 !can_have_last_resort(qstate->env, iq->dp->name,
1190                      iq->dp->namelen, iq->qchase.qclass, NULL)) {
1191             iq->refetch_glue = 0;
1192         }
1193
1194         /* Resolver Algorithm Step 1 -- Look for the answer in local data. */
1195
1196         /* This either results in a query restart (CNAME cache response), a
1197          * terminating response (ANSWER), or a cache miss (null). */
1198
1199         if(qstate->blacklist) {
1200                 /* if cache, or anything else, was blacklisted then
1201                  * getting older results from cache is a bad idea, no cache */
1202                 verbose(VERB_ALGO, "cache blacklisted, going to the network");
1203                 msg = NULL;
1204         } else if(!qstate->no_cache_lookup) {
1205                 msg = dns_cache_lookup(qstate->env, iq->qchase.qname,
1206                         iq->qchase.qname_len, iq->qchase.qtype,
1207                         iq->qchase.qclass, qstate->query_flags,
1208                         qstate->region, qstate->env->scratch, 0);
1209                 if(!msg && qstate->env->neg_cache &&
1210                         iter_qname_indicates_dnssec(qstate->env, &iq->qchase)) {
1211                         /* lookup in negative cache; may result in
1212                          * NOERROR/NODATA or NXDOMAIN answers that need validation */
1213                         msg = val_neg_getmsg(qstate->env->neg_cache, &iq->qchase,
1214                                 qstate->region, qstate->env->rrset_cache,
1215                                 qstate->env->scratch_buffer,
1216                                 *qstate->env->now, 1/*add SOA*/, NULL,
1217                                 qstate->env->cfg);
1218                 }
1219                 /* item taken from cache does not match our query name, thus
1220                  * security needs to be re-examined later */
1221                 if(msg && query_dname_compare(qstate->qinfo.qname,
1222                         iq->qchase.qname) != 0)
1223                         msg->rep->security = sec_status_unchecked;
1224         }
1225         if(msg) {
1226                 /* handle positive cache response */
1227                 enum response_type type = response_type_from_cache(msg,
1228                         &iq->qchase);
1229                 if(verbosity >= VERB_ALGO) {
1230                         log_dns_msg("msg from cache lookup", &msg->qinfo,
1231                                 msg->rep);
1232                         verbose(VERB_ALGO, "msg ttl is %d, prefetch ttl %d",
1233                                 (int)msg->rep->ttl,
1234                                 (int)msg->rep->prefetch_ttl);
1235                 }
1236
1237                 if(type == RESPONSE_TYPE_CNAME) {
1238                         uint8_t* sname = 0;
1239                         size_t slen = 0;
1240                         verbose(VERB_ALGO, "returning CNAME response from "
1241                                 "cache");
1242                         if(!handle_cname_response(qstate, iq, msg,
1243                                 &sname, &slen))
1244                                 return error_response(qstate, id,
1245                                         LDNS_RCODE_SERVFAIL);
1246                         iq->qchase.qname = sname;
1247                         iq->qchase.qname_len = slen;
1248                         /* This *is* a query restart, even if it is a cheap
1249                          * one. */
1250                         iq->dp = NULL;
1251                         iq->refetch_glue = 0;
1252                         iq->query_restart_count++;
1253                         iq->sent_count = 0;
1254                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1255                         if(qstate->env->cfg->qname_minimisation)
1256                                 iq->minimisation_state = INIT_MINIMISE_STATE;
1257                         return next_state(iq, INIT_REQUEST_STATE);
1258                 }
1259
1260                 /* if from cache, NULL, else insert 'cache IP' len=0 */
1261                 if(qstate->reply_origin)
1262                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1263                 /* it is an answer, response, to final state */
1264                 verbose(VERB_ALGO, "returning answer from cache.");
1265                 iq->response = msg;
1266                 return final_state(iq);
1267         }
1268
1269         /* attempt to forward the request */
1270         if(forward_request(qstate, iq))
1271         {
1272                 if(!iq->dp) {
1273                         log_err("alloc failure for forward dp");
1274                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1275                 }
1276                 iq->refetch_glue = 0;
1277                 iq->minimisation_state = DONOT_MINIMISE_STATE;
1278                 /* the request has been forwarded.
1279                  * forwarded requests need to be immediately sent to the
1280                  * next state, QUERYTARGETS. */
1281                 return next_state(iq, QUERYTARGETS_STATE);
1282         }
1283
1284         /* Resolver Algorithm Step 2 -- find the "best" servers. */
1285
1286         /* first, adjust for DS queries. To avoid the grandparent problem,
1287          * we just look for the closest set of server to the parent of qname.
1288          * When re-fetching glue we also need to ask the parent.
1289          */
1290         if(iq->refetch_glue) {
1291                 if(!iq->dp) {
1292                         log_err("internal or malloc fail: no dp for refetch");
1293                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1294                 }
1295                 delname = iq->dp->name;
1296                 delnamelen = iq->dp->namelen;
1297         } else {
1298                 delname = iq->qchase.qname;
1299                 delnamelen = iq->qchase.qname_len;
1300         }
1301         if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue ||
1302            (iq->qchase.qtype == LDNS_RR_TYPE_NS && qstate->prefetch_leeway
1303            && can_have_last_resort(qstate->env, delname, delnamelen, iq->qchase.qclass, NULL))) {
1304                 /* remove first label from delname, root goes to hints,
1305                  * but only to fetch glue, not for qtype=DS. */
1306                 /* also when prefetching an NS record, fetch it again from
1307                  * its parent, just as if it expired, so that you do not
1308                  * get stuck on an older nameserver that gives old NSrecords */
1309                 if(dname_is_root(delname) && (iq->refetch_glue ||
1310                         (iq->qchase.qtype == LDNS_RR_TYPE_NS &&
1311                         qstate->prefetch_leeway)))
1312                         delname = NULL; /* go to root priming */
1313                 else    dname_remove_label(&delname, &delnamelen);
1314         }
1315         /* delname is the name to lookup a delegation for. If NULL rootprime */
1316         while(1) {
1317
1318                 /* Lookup the delegation in the cache. If null, then the
1319                  * cache needs to be primed for the qclass. */
1320                 if(delname)
1321                      iq->dp = dns_cache_find_delegation(qstate->env, delname,
1322                         delnamelen, iq->qchase.qtype, iq->qchase.qclass,
1323                         qstate->region, &iq->deleg_msg,
1324                         *qstate->env->now+qstate->prefetch_leeway);
1325                 else iq->dp = NULL;
1326
1327                 /* If the cache has returned nothing, then we have a
1328                  * root priming situation. */
1329                 if(iq->dp == NULL) {
1330                         int r;
1331                         /* if under auth zone, no prime needed */
1332                         if(!auth_zone_delegpt(qstate, iq, delname, delnamelen))
1333                                 return error_response(qstate, id,
1334                                         LDNS_RCODE_SERVFAIL);
1335                         if(iq->dp) /* use auth zone dp */
1336                                 return next_state(iq, INIT_REQUEST_2_STATE);
1337                         /* if there is a stub, then no root prime needed */
1338                         r = prime_stub(qstate, iq, id, delname,
1339                                 iq->qchase.qclass);
1340                         if(r == 2)
1341                                 break; /* got noprime-stub-zone, continue */
1342                         else if(r)
1343                                 return 0; /* stub prime request made */
1344                         if(forwards_lookup_root(qstate->env->fwds,
1345                                 iq->qchase.qclass)) {
1346                                 /* forward zone root, no root prime needed */
1347                                 /* fill in some dp - safety belt */
1348                                 iq->dp = hints_lookup_root(qstate->env->hints,
1349                                         iq->qchase.qclass);
1350                                 if(!iq->dp) {
1351                                         log_err("internal error: no hints dp");
1352                                         return error_response(qstate, id,
1353                                                 LDNS_RCODE_SERVFAIL);
1354                                 }
1355                                 iq->dp = delegpt_copy(iq->dp, qstate->region);
1356                                 if(!iq->dp) {
1357                                         log_err("out of memory in safety belt");
1358                                         return error_response(qstate, id,
1359                                                 LDNS_RCODE_SERVFAIL);
1360                                 }
1361                                 return next_state(iq, INIT_REQUEST_2_STATE);
1362                         }
1363                         /* Note that the result of this will set a new
1364                          * DelegationPoint based on the result of priming. */
1365                         if(!prime_root(qstate, iq, id, iq->qchase.qclass))
1366                                 return error_response(qstate, id,
1367                                         LDNS_RCODE_REFUSED);
1368
1369                         /* priming creates and sends a subordinate query, with
1370                          * this query as the parent. So further processing for
1371                          * this event will stop until reactivated by the
1372                          * results of priming. */
1373                         return 0;
1374                 }
1375                 if(!iq->ratelimit_ok && qstate->prefetch_leeway)
1376                         iq->ratelimit_ok = 1; /* allow prefetches, this keeps
1377                         otherwise valid data in the cache */
1378                 if(!iq->ratelimit_ok && infra_ratelimit_exceeded(
1379                         qstate->env->infra_cache, iq->dp->name,
1380                         iq->dp->namelen, *qstate->env->now)) {
1381                         /* and increment the rate, so that the rate for time
1382                          * now will also exceed the rate, keeping cache fresh */
1383                         (void)infra_ratelimit_inc(qstate->env->infra_cache,
1384                                 iq->dp->name, iq->dp->namelen,
1385                                 *qstate->env->now);
1386                         /* see if we are passed through with slip factor */
1387                         if(qstate->env->cfg->ratelimit_factor != 0 &&
1388                                 ub_random_max(qstate->env->rnd,
1389                                     qstate->env->cfg->ratelimit_factor) == 1) {
1390                                 iq->ratelimit_ok = 1;
1391                                 log_nametypeclass(VERB_ALGO, "ratelimit allowed through for "
1392                                         "delegation point", iq->dp->name,
1393                                         LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
1394                         } else {
1395                                 lock_basic_lock(&ie->queries_ratelimit_lock);
1396                                 ie->num_queries_ratelimited++;
1397                                 lock_basic_unlock(&ie->queries_ratelimit_lock);
1398                                 log_nametypeclass(VERB_ALGO, "ratelimit exceeded with "
1399                                         "delegation point", iq->dp->name,
1400                                         LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
1401                                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1402                         }
1403                 }
1404
1405                 /* see if this dp not useless.
1406                  * It is useless if:
1407                  *      o all NS items are required glue.
1408                  *        or the query is for NS item that is required glue.
1409                  *      o no addresses are provided.
1410                  *      o RD qflag is on.
1411                  * Instead, go up one level, and try to get even further
1412                  * If the root was useless, use safety belt information.
1413                  * Only check cache returns, because replies for servers
1414                  * could be useless but lead to loops (bumping into the
1415                  * same server reply) if useless-checked.
1416                  */
1417                 if(iter_dp_is_useless(&qstate->qinfo, qstate->query_flags,
1418                         iq->dp)) {
1419                         struct delegpt* retdp = NULL;
1420                         if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen, iq->qchase.qclass, &retdp)) {
1421                                 if(retdp) {
1422                                         verbose(VERB_QUERY, "cache has stub "
1423                                                 "or fwd but no addresses, "
1424                                                 "fallback to config");
1425                                         iq->dp = delegpt_copy(retdp,
1426                                                 qstate->region);
1427                                         if(!iq->dp) {
1428                                                 log_err("out of memory in "
1429                                                         "stub/fwd fallback");
1430                                                 return error_response(qstate,
1431                                                     id, LDNS_RCODE_SERVFAIL);
1432                                         }
1433                                         break;
1434                                 }
1435                                 verbose(VERB_ALGO, "useless dp "
1436                                         "but cannot go up, servfail");
1437                                 delegpt_log(VERB_ALGO, iq->dp);
1438                                 return error_response(qstate, id,
1439                                         LDNS_RCODE_SERVFAIL);
1440                         }
1441                         if(dname_is_root(iq->dp->name)) {
1442                                 /* use safety belt */
1443                                 verbose(VERB_QUERY, "Cache has root NS but "
1444                                 "no addresses. Fallback to the safety belt.");
1445                                 iq->dp = hints_lookup_root(qstate->env->hints,
1446                                         iq->qchase.qclass);
1447                                 /* note deleg_msg is from previous lookup,
1448                                  * but RD is on, so it is not used */
1449                                 if(!iq->dp) {
1450                                         log_err("internal error: no hints dp");
1451                                         return error_response(qstate, id,
1452                                                 LDNS_RCODE_REFUSED);
1453                                 }
1454                                 iq->dp = delegpt_copy(iq->dp, qstate->region);
1455                                 if(!iq->dp) {
1456                                         log_err("out of memory in safety belt");
1457                                         return error_response(qstate, id,
1458                                                 LDNS_RCODE_SERVFAIL);
1459                                 }
1460                                 break;
1461                         } else {
1462                                 verbose(VERB_ALGO,
1463                                         "cache delegation was useless:");
1464                                 delegpt_log(VERB_ALGO, iq->dp);
1465                                 /* go up */
1466                                 delname = iq->dp->name;
1467                                 delnamelen = iq->dp->namelen;
1468                                 dname_remove_label(&delname, &delnamelen);
1469                         }
1470                 } else break;
1471         }
1472
1473         verbose(VERB_ALGO, "cache delegation returns delegpt");
1474         delegpt_log(VERB_ALGO, iq->dp);
1475
1476         /* Otherwise, set the current delegation point and move on to the
1477          * next state. */
1478         return next_state(iq, INIT_REQUEST_2_STATE);
1479 }
1480
1481 /**
1482  * Process the second part of the initial request handling. This state
1483  * basically exists so that queries that generate root priming events have
1484  * the same init processing as ones that do not. Request events that reach
1485  * this state must have a valid currentDelegationPoint set.
1486  *
1487  * This part is primarily handling stub zone priming. Events that reach this
1488  * state must have a current delegation point.
1489  *
1490  * @param qstate: query state.
1491  * @param iq: iterator query state.
1492  * @param id: module id.
1493  * @return true if the event needs more request processing immediately,
1494  *         false if not.
1495  */
1496 static int
1497 processInitRequest2(struct module_qstate* qstate, struct iter_qstate* iq,
1498         int id)
1499 {
1500         uint8_t* delname;
1501         size_t delnamelen;
1502         log_query_info(VERB_QUERY, "resolving (init part 2): ",
1503                 &qstate->qinfo);
1504
1505         delname = iq->qchase.qname;
1506         delnamelen = iq->qchase.qname_len;
1507         if(iq->refetch_glue) {
1508                 struct iter_hints_stub* stub;
1509                 if(!iq->dp) {
1510                         log_err("internal or malloc fail: no dp for refetch");
1511                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1512                 }
1513                 /* Do not send queries above stub, do not set delname to dp if
1514                  * this is above stub without stub-first. */
1515                 stub = hints_lookup_stub(
1516                         qstate->env->hints, iq->qchase.qname, iq->qchase.qclass,
1517                         iq->dp);
1518                 if(!stub || !stub->dp->has_parent_side_NS ||
1519                         dname_subdomain_c(iq->dp->name, stub->dp->name)) {
1520                         delname = iq->dp->name;
1521                         delnamelen = iq->dp->namelen;
1522                 }
1523         }
1524         if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue) {
1525                 if(!dname_is_root(delname))
1526                         dname_remove_label(&delname, &delnamelen);
1527                 iq->refetch_glue = 0; /* if CNAME causes restart, no refetch */
1528         }
1529
1530         /* see if we have an auth zone to answer from, improves dp from cache
1531          * (if any dp from cache) with auth zone dp, if that is lower */
1532         if(!auth_zone_delegpt(qstate, iq, delname, delnamelen))
1533                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1534
1535         /* Check to see if we need to prime a stub zone. */
1536         if(prime_stub(qstate, iq, id, delname, iq->qchase.qclass)) {
1537                 /* A priming sub request was made */
1538                 return 0;
1539         }
1540
1541         /* most events just get forwarded to the next state. */
1542         return next_state(iq, INIT_REQUEST_3_STATE);
1543 }
1544
1545 /**
1546  * Process the third part of the initial request handling. This state exists
1547  * as a separate state so that queries that generate stub priming events
1548  * will get the tail end of the init process but not repeat the stub priming
1549  * check.
1550  *
1551  * @param qstate: query state.
1552  * @param iq: iterator query state.
1553  * @param id: module id.
1554  * @return true, advancing the event to the QUERYTARGETS_STATE.
1555  */
1556 static int
1557 processInitRequest3(struct module_qstate* qstate, struct iter_qstate* iq,
1558         int id)
1559 {
1560         log_query_info(VERB_QUERY, "resolving (init part 3): ",
1561                 &qstate->qinfo);
1562         /* if the cache reply dp equals a validation anchor or msg has DS,
1563          * then DNSSEC RRSIGs are expected in the reply */
1564         iq->dnssec_expected = iter_indicates_dnssec(qstate->env, iq->dp,
1565                 iq->deleg_msg, iq->qchase.qclass);
1566
1567         /* If the RD flag wasn't set, then we just finish with the
1568          * cached referral as the response. */
1569         if(!(qstate->query_flags & BIT_RD) && iq->deleg_msg) {
1570                 iq->response = iq->deleg_msg;
1571                 if(verbosity >= VERB_ALGO && iq->response)
1572                         log_dns_msg("no RD requested, using delegation msg",
1573                                 &iq->response->qinfo, iq->response->rep);
1574                 if(qstate->reply_origin)
1575                         sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1576                 return final_state(iq);
1577         }
1578         /* After this point, unset the RD flag -- this query is going to
1579          * be sent to an auth. server. */
1580         iq->chase_flags &= ~BIT_RD;
1581
1582         /* if dnssec expected, fetch key for the trust-anchor or cached-DS */
1583         if(iq->dnssec_expected && qstate->env->cfg->prefetch_key &&
1584                 !(qstate->query_flags&BIT_CD)) {
1585                 generate_dnskey_prefetch(qstate, iq, id);
1586                 fptr_ok(fptr_whitelist_modenv_detach_subs(
1587                         qstate->env->detach_subs));
1588                 (*qstate->env->detach_subs)(qstate);
1589         }
1590
1591         /* Jump to the next state. */
1592         return next_state(iq, QUERYTARGETS_STATE);
1593 }
1594
1595 /**
1596  * Given a basic query, generate a parent-side "target" query.
1597  * These are subordinate queries for missing delegation point target addresses,
1598  * for which only the parent of the delegation provides correct IP addresses.
1599  *
1600  * @param qstate: query state.
1601  * @param iq: iterator query state.
1602  * @param id: module id.
1603  * @param name: target qname.
1604  * @param namelen: target qname length.
1605  * @param qtype: target qtype (either A or AAAA).
1606  * @param qclass: target qclass.
1607  * @return true on success, false on failure.
1608  */
1609 static int
1610 generate_parentside_target_query(struct module_qstate* qstate,
1611         struct iter_qstate* iq, int id, uint8_t* name, size_t namelen,
1612         uint16_t qtype, uint16_t qclass)
1613 {
1614         struct module_qstate* subq;
1615         if(!generate_sub_request(name, namelen, qtype, qclass, qstate,
1616                 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0))
1617                 return 0;
1618         if(subq) {
1619                 struct iter_qstate* subiq =
1620                         (struct iter_qstate*)subq->minfo[id];
1621                 /* blacklist the cache - we want to fetch parent stuff */
1622                 sock_list_insert(&subq->blacklist, NULL, 0, subq->region);
1623                 subiq->query_for_pside_glue = 1;
1624                 if(dname_subdomain_c(name, iq->dp->name)) {
1625                         subiq->dp = delegpt_copy(iq->dp, subq->region);
1626                         subiq->dnssec_expected = iter_indicates_dnssec(
1627                                 qstate->env, subiq->dp, NULL,
1628                                 subq->qinfo.qclass);
1629                         subiq->refetch_glue = 1;
1630                 } else {
1631                         subiq->dp = dns_cache_find_delegation(qstate->env,
1632                                 name, namelen, qtype, qclass, subq->region,
1633                                 &subiq->deleg_msg,
1634                                 *qstate->env->now+subq->prefetch_leeway);
1635                         /* if no dp, then it's from root, refetch unneeded */
1636                         if(subiq->dp) {
1637                                 subiq->dnssec_expected = iter_indicates_dnssec(
1638                                         qstate->env, subiq->dp, NULL,
1639                                         subq->qinfo.qclass);
1640                                 subiq->refetch_glue = 1;
1641                         }
1642                 }
1643         }
1644         log_nametypeclass(VERB_QUERY, "new pside target", name, qtype, qclass);
1645         return 1;
1646 }
1647
1648 /**
1649  * Given a basic query, generate a "target" query. These are subordinate
1650  * queries for missing delegation point target addresses.
1651  *
1652  * @param qstate: query state.
1653  * @param iq: iterator query state.
1654  * @param id: module id.
1655  * @param name: target qname.
1656  * @param namelen: target qname length.
1657  * @param qtype: target qtype (either A or AAAA).
1658  * @param qclass: target qclass.
1659  * @return true on success, false on failure.
1660  */
1661 static int
1662 generate_target_query(struct module_qstate* qstate, struct iter_qstate* iq,
1663         int id, uint8_t* name, size_t namelen, uint16_t qtype, uint16_t qclass)
1664 {
1665         struct module_qstate* subq;
1666         if(!generate_sub_request(name, namelen, qtype, qclass, qstate,
1667                 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0))
1668                 return 0;
1669         log_nametypeclass(VERB_QUERY, "new target", name, qtype, qclass);
1670         return 1;
1671 }
1672
1673 /**
1674  * Given an event at a certain state, generate zero or more target queries
1675  * for it's current delegation point.
1676  *
1677  * @param qstate: query state.
1678  * @param iq: iterator query state.
1679  * @param ie: iterator shared global environment.
1680  * @param id: module id.
1681  * @param maxtargets: The maximum number of targets to query for.
1682  *      if it is negative, there is no maximum number of targets.
1683  * @param num: returns the number of queries generated and processed,
1684  *      which may be zero if there were no missing targets.
1685  * @return false on error.
1686  */
1687 static int
1688 query_for_targets(struct module_qstate* qstate, struct iter_qstate* iq,
1689         struct iter_env* ie, int id, int maxtargets, int* num)
1690 {
1691         int query_count = 0;
1692         struct delegpt_ns* ns;
1693         int missing;
1694         int toget = 0;
1695
1696         if(iq->depth == ie->max_dependency_depth)
1697                 return 0;
1698         if(iq->depth > 0 && iq->target_count &&
1699                 iq->target_count[1] > MAX_TARGET_COUNT) {
1700                 char s[LDNS_MAX_DOMAINLEN+1];
1701                 dname_str(qstate->qinfo.qname, s);
1702                 verbose(VERB_QUERY, "request %s has exceeded the maximum "
1703                         "number of glue fetches %d", s, iq->target_count[1]);
1704                 return 0;
1705         }
1706
1707         iter_mark_cycle_targets(qstate, iq->dp);
1708         missing = (int)delegpt_count_missing_targets(iq->dp);
1709         log_assert(maxtargets != 0); /* that would not be useful */
1710
1711         /* Generate target requests. Basically, any missing targets
1712          * are queried for here, regardless if it is necessary to do
1713          * so to continue processing. */
1714         if(maxtargets < 0 || maxtargets > missing)
1715                 toget = missing;
1716         else    toget = maxtargets;
1717         if(toget == 0) {
1718                 *num = 0;
1719                 return 1;
1720         }
1721         /* select 'toget' items from the total of 'missing' items */
1722         log_assert(toget <= missing);
1723
1724         /* loop over missing targets */
1725         for(ns = iq->dp->nslist; ns; ns = ns->next) {
1726                 if(ns->resolved)
1727                         continue;
1728
1729                 /* randomly select this item with probability toget/missing */
1730                 if(!iter_ns_probability(qstate->env->rnd, toget, missing)) {
1731                         /* do not select this one, next; select toget number
1732                          * of items from a list one less in size */
1733                         missing --;
1734                         continue;
1735                 }
1736
1737                 if(ie->supports_ipv6 && !ns->got6) {
1738                         /* Send the AAAA request. */
1739                         if(!generate_target_query(qstate, iq, id,
1740                                 ns->name, ns->namelen,
1741                                 LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) {
1742                                 *num = query_count;
1743                                 if(query_count > 0)
1744                                         qstate->ext_state[id] = module_wait_subquery;
1745                                 return 0;
1746                         }
1747                         query_count++;
1748                 }
1749                 /* Send the A request. */
1750                 if(ie->supports_ipv4 && !ns->got4) {
1751                         if(!generate_target_query(qstate, iq, id,
1752                                 ns->name, ns->namelen,
1753                                 LDNS_RR_TYPE_A, iq->qchase.qclass)) {
1754                                 *num = query_count;
1755                                 if(query_count > 0)
1756                                         qstate->ext_state[id] = module_wait_subquery;
1757                                 return 0;
1758                         }
1759                         query_count++;
1760                 }
1761
1762                 /* mark this target as in progress. */
1763                 ns->resolved = 1;
1764                 missing--;
1765                 toget--;
1766                 if(toget == 0)
1767                         break;
1768         }
1769         *num = query_count;
1770         if(query_count > 0)
1771                 qstate->ext_state[id] = module_wait_subquery;
1772
1773         return 1;
1774 }
1775
1776 /**
1777  * Called by processQueryTargets when it would like extra targets to query
1778  * but it seems to be out of options.  At last resort some less appealing
1779  * options are explored.  If there are no more options, the result is SERVFAIL
1780  *
1781  * @param qstate: query state.
1782  * @param iq: iterator query state.
1783  * @param ie: iterator shared global environment.
1784  * @param id: module id.
1785  * @return true if the event requires more request processing immediately,
1786  *         false if not.
1787  */
1788 static int
1789 processLastResort(struct module_qstate* qstate, struct iter_qstate* iq,
1790         struct iter_env* ie, int id)
1791 {
1792         struct delegpt_ns* ns;
1793         int query_count = 0;
1794         verbose(VERB_ALGO, "No more query targets, attempting last resort");
1795         log_assert(iq->dp);
1796
1797         if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen,
1798                 iq->qchase.qclass, NULL)) {
1799                 /* fail -- no more targets, no more hope of targets, no hope
1800                  * of a response. */
1801                 verbose(VERB_QUERY, "configured stub or forward servers failed -- returning SERVFAIL");
1802                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1803         }
1804         if(!iq->dp->has_parent_side_NS && dname_is_root(iq->dp->name)) {
1805                 struct delegpt* p = hints_lookup_root(qstate->env->hints,
1806                         iq->qchase.qclass);
1807                 if(p) {
1808                         struct delegpt_ns* ns;
1809                         struct delegpt_addr* a;
1810                         iq->chase_flags &= ~BIT_RD; /* go to authorities */
1811                         for(ns = p->nslist; ns; ns=ns->next) {
1812                                 (void)delegpt_add_ns(iq->dp, qstate->region,
1813                                         ns->name, ns->lame);
1814                         }
1815                         for(a = p->target_list; a; a=a->next_target) {
1816                                 (void)delegpt_add_addr(iq->dp, qstate->region,
1817                                         &a->addr, a->addrlen, a->bogus,
1818                                         a->lame, a->tls_auth_name);
1819                         }
1820                 }
1821                 iq->dp->has_parent_side_NS = 1;
1822         } else if(!iq->dp->has_parent_side_NS) {
1823                 if(!iter_lookup_parent_NS_from_cache(qstate->env, iq->dp,
1824                         qstate->region, &qstate->qinfo)
1825                         || !iq->dp->has_parent_side_NS) {
1826                         /* if: malloc failure in lookup go up to try */
1827                         /* if: no parent NS in cache - go up one level */
1828                         verbose(VERB_ALGO, "try to grab parent NS");
1829                         iq->store_parent_NS = iq->dp;
1830                         iq->chase_flags &= ~BIT_RD; /* go to authorities */
1831                         iq->deleg_msg = NULL;
1832                         iq->refetch_glue = 1;
1833                         iq->query_restart_count++;
1834                         iq->sent_count = 0;
1835                         if(qstate->env->cfg->qname_minimisation)
1836                                 iq->minimisation_state = INIT_MINIMISE_STATE;
1837                         return next_state(iq, INIT_REQUEST_STATE);
1838                 }
1839         }
1840         /* see if that makes new names available */
1841         if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
1842                 qstate->region, iq->dp))
1843                 log_err("out of memory in cache_fill_missing");
1844         if(iq->dp->usable_list) {
1845                 verbose(VERB_ALGO, "try parent-side-name, w. glue from cache");
1846                 return next_state(iq, QUERYTARGETS_STATE);
1847         }
1848         /* try to fill out parent glue from cache */
1849         if(iter_lookup_parent_glue_from_cache(qstate->env, iq->dp,
1850                 qstate->region, &qstate->qinfo)) {
1851                 /* got parent stuff from cache, see if we can continue */
1852                 verbose(VERB_ALGO, "try parent-side glue from cache");
1853                 return next_state(iq, QUERYTARGETS_STATE);
1854         }
1855         /* query for an extra name added by the parent-NS record */
1856         if(delegpt_count_missing_targets(iq->dp) > 0) {
1857                 int qs = 0;
1858                 verbose(VERB_ALGO, "try parent-side target name");
1859                 if(!query_for_targets(qstate, iq, ie, id, 1, &qs)) {
1860                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1861                 }
1862                 iq->num_target_queries += qs;
1863                 target_count_increase(iq, qs);
1864                 if(qs != 0) {
1865                         qstate->ext_state[id] = module_wait_subquery;
1866                         return 0; /* and wait for them */
1867                 }
1868         }
1869         if(iq->depth == ie->max_dependency_depth) {
1870                 verbose(VERB_QUERY, "maxdepth and need more nameservers, fail");
1871                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1872         }
1873         if(iq->depth > 0 && iq->target_count &&
1874                 iq->target_count[1] > MAX_TARGET_COUNT) {
1875                 char s[LDNS_MAX_DOMAINLEN+1];
1876                 dname_str(qstate->qinfo.qname, s);
1877                 verbose(VERB_QUERY, "request %s has exceeded the maximum "
1878                         "number of glue fetches %d", s, iq->target_count[1]);
1879                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1880         }
1881         /* mark cycle targets for parent-side lookups */
1882         iter_mark_pside_cycle_targets(qstate, iq->dp);
1883         /* see if we can issue queries to get nameserver addresses */
1884         /* this lookup is not randomized, but sequential. */
1885         for(ns = iq->dp->nslist; ns; ns = ns->next) {
1886                 /* if this nameserver is at a delegation point, but that
1887                  * delegation point is a stub and we cannot go higher, skip*/
1888                 if( ((ie->supports_ipv6 && !ns->done_pside6) ||
1889                     (ie->supports_ipv4 && !ns->done_pside4)) &&
1890                     !can_have_last_resort(qstate->env, ns->name, ns->namelen,
1891                         iq->qchase.qclass, NULL)) {
1892                         log_nametypeclass(VERB_ALGO, "cannot pside lookup ns "
1893                                 "because it is also a stub/forward,",
1894                                 ns->name, LDNS_RR_TYPE_NS, iq->qchase.qclass);
1895                         if(ie->supports_ipv6) ns->done_pside6 = 1;
1896                         if(ie->supports_ipv4) ns->done_pside4 = 1;
1897                         continue;
1898                 }
1899                 /* query for parent-side A and AAAA for nameservers */
1900                 if(ie->supports_ipv6 && !ns->done_pside6) {
1901                         /* Send the AAAA request. */
1902                         if(!generate_parentside_target_query(qstate, iq, id,
1903                                 ns->name, ns->namelen,
1904                                 LDNS_RR_TYPE_AAAA, iq->qchase.qclass))
1905                                 return error_response(qstate, id,
1906                                         LDNS_RCODE_SERVFAIL);
1907                         ns->done_pside6 = 1;
1908                         query_count++;
1909                 }
1910                 if(ie->supports_ipv4 && !ns->done_pside4) {
1911                         /* Send the A request. */
1912                         if(!generate_parentside_target_query(qstate, iq, id,
1913                                 ns->name, ns->namelen,
1914                                 LDNS_RR_TYPE_A, iq->qchase.qclass))
1915                                 return error_response(qstate, id,
1916                                         LDNS_RCODE_SERVFAIL);
1917                         ns->done_pside4 = 1;
1918                         query_count++;
1919                 }
1920                 if(query_count != 0) { /* suspend to await results */
1921                         verbose(VERB_ALGO, "try parent-side glue lookup");
1922                         iq->num_target_queries += query_count;
1923                         target_count_increase(iq, query_count);
1924                         qstate->ext_state[id] = module_wait_subquery;
1925                         return 0;
1926                 }
1927         }
1928
1929         /* if this was a parent-side glue query itself, then store that
1930          * failure in cache. */
1931         if(!qstate->no_cache_store && iq->query_for_pside_glue
1932                 && !iq->pside_glue)
1933                         iter_store_parentside_neg(qstate->env, &qstate->qinfo,
1934                                 iq->deleg_msg?iq->deleg_msg->rep:
1935                                 (iq->response?iq->response->rep:NULL));
1936
1937         verbose(VERB_QUERY, "out of query targets -- returning SERVFAIL");
1938         /* fail -- no more targets, no more hope of targets, no hope
1939          * of a response. */
1940         return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1941 }
1942
1943 /**
1944  * Try to find the NS record set that will resolve a qtype DS query. Due
1945  * to grandparent/grandchild reasons we did not get a proper lookup right
1946  * away.  We need to create type NS queries until we get the right parent
1947  * for this lookup.  We remove labels from the query to find the right point.
1948  * If we end up at the old dp name, then there is no solution.
1949  *
1950  * @param qstate: query state.
1951  * @param iq: iterator query state.
1952  * @param id: module id.
1953  * @return true if the event requires more immediate processing, false if
1954  *         not. This is generally only true when forwarding the request to
1955  *         the final state (i.e., on answer).
1956  */
1957 static int
1958 processDSNSFind(struct module_qstate* qstate, struct iter_qstate* iq, int id)
1959 {
1960         struct module_qstate* subq = NULL;
1961         verbose(VERB_ALGO, "processDSNSFind");
1962
1963         if(!iq->dsns_point) {
1964                 /* initialize */
1965                 iq->dsns_point = iq->qchase.qname;
1966                 iq->dsns_point_len = iq->qchase.qname_len;
1967         }
1968         /* robustcheck for internal error: we are not underneath the dp */
1969         if(!dname_subdomain_c(iq->dsns_point, iq->dp->name)) {
1970                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1971         }
1972
1973         /* go up one (more) step, until we hit the dp, if so, end */
1974         dname_remove_label(&iq->dsns_point, &iq->dsns_point_len);
1975         if(query_dname_compare(iq->dsns_point, iq->dp->name) == 0) {
1976                 /* there was no inbetween nameserver, use the old delegation
1977                  * point again.  And this time, because dsns_point is nonNULL
1978                  * we are going to accept the (bad) result */
1979                 iq->state = QUERYTARGETS_STATE;
1980                 return 1;
1981         }
1982         iq->state = DSNS_FIND_STATE;
1983
1984         /* spawn NS lookup (validation not needed, this is for DS lookup) */
1985         log_nametypeclass(VERB_ALGO, "fetch nameservers",
1986                 iq->dsns_point, LDNS_RR_TYPE_NS, iq->qchase.qclass);
1987         if(!generate_sub_request(iq->dsns_point, iq->dsns_point_len,
1988                 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
1989                 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0)) {
1990                 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
1991         }
1992
1993         return 0;
1994 }
1995
1996 /**
1997  * This is the request event state where the request will be sent to one of
1998  * its current query targets. This state also handles issuing target lookup
1999  * queries for missing target IP addresses. Queries typically iterate on
2000  * this state, both when they are just trying different targets for a given
2001  * delegation point, and when they change delegation points. This state
2002  * roughly corresponds to RFC 1034 algorithm steps 3 and 4.
2003  *
2004  * @param qstate: query state.
2005  * @param iq: iterator query state.
2006  * @param ie: iterator shared global environment.
2007  * @param id: module id.
2008  * @return true if the event requires more request processing immediately,
2009  *         false if not. This state only returns true when it is generating
2010  *         a SERVFAIL response because the query has hit a dead end.
2011  */
2012 static int
2013 processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
2014         struct iter_env* ie, int id)
2015 {
2016         int tf_policy;
2017         struct delegpt_addr* target;
2018         struct outbound_entry* outq;
2019         int auth_fallback = 0;
2020
2021         /* NOTE: a request will encounter this state for each target it
2022          * needs to send a query to. That is, at least one per referral,
2023          * more if some targets timeout or return throwaway answers. */
2024
2025         log_query_info(VERB_QUERY, "processQueryTargets:", &qstate->qinfo);
2026         verbose(VERB_ALGO, "processQueryTargets: targetqueries %d, "
2027                 "currentqueries %d sentcount %d", iq->num_target_queries,
2028                 iq->num_current_queries, iq->sent_count);
2029
2030         /* Make sure that we haven't run away */
2031         /* FIXME: is this check even necessary? */
2032         if(iq->referral_count > MAX_REFERRAL_COUNT) {
2033                 verbose(VERB_QUERY, "request has exceeded the maximum "
2034                         "number of referrrals with %d", iq->referral_count);
2035                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2036         }
2037         if(iq->sent_count > MAX_SENT_COUNT) {
2038                 verbose(VERB_QUERY, "request has exceeded the maximum "
2039                         "number of sends with %d", iq->sent_count);
2040                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2041         }
2042
2043         /* Make sure we have a delegation point, otherwise priming failed
2044          * or another failure occurred */
2045         if(!iq->dp) {
2046                 verbose(VERB_QUERY, "Failed to get a delegation, giving up");
2047                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2048         }
2049         if(!ie->supports_ipv6)
2050                 delegpt_no_ipv6(iq->dp);
2051         if(!ie->supports_ipv4)
2052                 delegpt_no_ipv4(iq->dp);
2053         delegpt_log(VERB_ALGO, iq->dp);
2054
2055         if(iq->num_current_queries>0) {
2056                 /* already busy answering a query, this restart is because
2057                  * more delegpt addrs became available, wait for existing
2058                  * query. */
2059                 verbose(VERB_ALGO, "woke up, but wait for outstanding query");
2060                 qstate->ext_state[id] = module_wait_reply;
2061                 return 0;
2062         }
2063
2064         if(iq->minimisation_state == INIT_MINIMISE_STATE) {
2065                 /* (Re)set qinfo_out to (new) delegation point, except when
2066                  * qinfo_out is already a subdomain of dp. This happens when
2067                  * increasing by more than one label at once (QNAMEs with more
2068                  * than MAX_MINIMISE_COUNT labels). */
2069                 if(!(iq->qinfo_out.qname_len
2070                         && dname_subdomain_c(iq->qchase.qname,
2071                                 iq->qinfo_out.qname)
2072                         && dname_subdomain_c(iq->qinfo_out.qname,
2073                                 iq->dp->name))) {
2074                         iq->qinfo_out.qname = iq->dp->name;
2075                         iq->qinfo_out.qname_len = iq->dp->namelen;
2076                         iq->qinfo_out.qtype = LDNS_RR_TYPE_A;
2077                         iq->qinfo_out.qclass = iq->qchase.qclass;
2078                         iq->qinfo_out.local_alias = NULL;
2079                         iq->minimise_count = 0;
2080                 }
2081
2082                 iq->minimisation_state = MINIMISE_STATE;
2083         }
2084         if(iq->minimisation_state == MINIMISE_STATE) {
2085                 int qchaselabs = dname_count_labels(iq->qchase.qname);
2086                 int labdiff = qchaselabs -
2087                         dname_count_labels(iq->qinfo_out.qname);
2088
2089                 iq->qinfo_out.qname = iq->qchase.qname;
2090                 iq->qinfo_out.qname_len = iq->qchase.qname_len;
2091                 iq->minimise_count++;
2092                 iq->minimise_timeout_count = 0;
2093
2094                 iter_dec_attempts(iq->dp, 1);
2095
2096                 /* Limit number of iterations for QNAMEs with more
2097                  * than MAX_MINIMISE_COUNT labels. Send first MINIMISE_ONE_LAB
2098                  * labels of QNAME always individually.
2099                  */
2100                 if(qchaselabs > MAX_MINIMISE_COUNT && labdiff > 1 &&
2101                         iq->minimise_count > MINIMISE_ONE_LAB) {
2102                         if(iq->minimise_count < MAX_MINIMISE_COUNT) {
2103                                 int multilabs = qchaselabs - 1 -
2104                                         MINIMISE_ONE_LAB;
2105                                 int extralabs = multilabs /
2106                                         MINIMISE_MULTIPLE_LABS;
2107
2108                                 if (MAX_MINIMISE_COUNT - iq->minimise_count >=
2109                                         multilabs % MINIMISE_MULTIPLE_LABS)
2110                                         /* Default behaviour is to add 1 label
2111                                          * every iteration. Therefore, decrement
2112                                          * the extralabs by 1 */
2113                                         extralabs--;
2114                                 if (extralabs < labdiff)
2115                                         labdiff -= extralabs;
2116                                 else
2117                                         labdiff = 1;
2118                         }
2119                         /* Last minimised iteration, send all labels with
2120                          * QTYPE=NS */
2121                         else
2122                                 labdiff = 1;
2123                 }
2124
2125                 if(labdiff > 1) {
2126                         verbose(VERB_QUERY, "removing %d labels", labdiff-1);
2127                         dname_remove_labels(&iq->qinfo_out.qname,
2128                                 &iq->qinfo_out.qname_len,
2129                                 labdiff-1);
2130                 }
2131                 if(labdiff < 1 || (labdiff < 2
2132                         && (iq->qchase.qtype == LDNS_RR_TYPE_DS
2133                         || iq->qchase.qtype == LDNS_RR_TYPE_A)))
2134                         /* Stop minimising this query, resolve "as usual" */
2135                         iq->minimisation_state = DONOT_MINIMISE_STATE;
2136                 else if(!qstate->no_cache_lookup) {
2137                         struct dns_msg* msg = dns_cache_lookup(qstate->env,
2138                                 iq->qinfo_out.qname, iq->qinfo_out.qname_len,
2139                                 iq->qinfo_out.qtype, iq->qinfo_out.qclass,
2140                                 qstate->query_flags, qstate->region,
2141                                 qstate->env->scratch, 0);
2142                         if(msg && msg->rep->an_numrrsets == 0
2143                                 && FLAGS_GET_RCODE(msg->rep->flags) ==
2144                                 LDNS_RCODE_NOERROR)
2145                                 /* no need to send query if it is already
2146                                  * cached as NOERROR/NODATA */
2147                                 return 1;
2148                 }
2149         }
2150         if(iq->minimisation_state == SKIP_MINIMISE_STATE) {
2151                 if(iq->minimise_timeout_count < MAX_MINIMISE_TIMEOUT_COUNT)
2152                         /* Do not increment qname, continue incrementing next
2153                          * iteration */
2154                         iq->minimisation_state = MINIMISE_STATE;
2155                 else if(!qstate->env->cfg->qname_minimisation_strict)
2156                         /* Too many time-outs detected for this QNAME and QTYPE.
2157                          * We give up, disable QNAME minimisation. */
2158                         iq->minimisation_state = DONOT_MINIMISE_STATE;
2159         }
2160         if(iq->minimisation_state == DONOT_MINIMISE_STATE)
2161                 iq->qinfo_out = iq->qchase;
2162
2163         /* now find an answer to this query */
2164         /* see if authority zones have an answer */
2165         /* now we know the dp, we can check the auth zone for locally hosted
2166          * contents */
2167         if(!iq->auth_zone_avoid && qstate->blacklist) {
2168                 if(auth_zones_can_fallback(qstate->env->auth_zones,
2169                         iq->dp->name, iq->dp->namelen, iq->qinfo_out.qclass)) {
2170                         /* if cache is blacklisted and this zone allows us
2171                          * to fallback to the internet, then do so, and
2172                          * fetch results from the internet servers */
2173                         iq->auth_zone_avoid = 1;
2174                 }
2175         }
2176         if(iq->auth_zone_avoid) {
2177                 iq->auth_zone_avoid = 0;
2178                 auth_fallback = 1;
2179         } else if(auth_zones_lookup(qstate->env->auth_zones, &iq->qinfo_out,
2180                 qstate->region, &iq->response, &auth_fallback, iq->dp->name,
2181                 iq->dp->namelen)) {
2182                 /* use this as a response to be processed by the iterator */
2183                 if(verbosity >= VERB_ALGO) {
2184                         log_dns_msg("msg from auth zone",
2185                                 &iq->response->qinfo, iq->response->rep);
2186                 }
2187                 if((iq->chase_flags&BIT_RD) && !(iq->response->rep->flags&BIT_AA)) {
2188                         verbose(VERB_ALGO, "forwarder, ignoring referral from auth zone");
2189                 } else {
2190                         lock_rw_wrlock(&qstate->env->auth_zones->lock);
2191                         qstate->env->auth_zones->num_query_up++;
2192                         lock_rw_unlock(&qstate->env->auth_zones->lock);
2193                         iq->num_current_queries++;
2194                         iq->chase_to_rd = 0;
2195                         iq->dnssec_lame_query = 0;
2196                         iq->auth_zone_response = 1;
2197                         return next_state(iq, QUERY_RESP_STATE);
2198                 }
2199         }
2200         iq->auth_zone_response = 0;
2201         if(auth_fallback == 0) {
2202                 /* like we got servfail from the auth zone lookup, and
2203                  * no internet fallback */
2204                 verbose(VERB_ALGO, "auth zone lookup failed, no fallback,"
2205                         " servfail");
2206                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2207         }
2208         if(iq->dp && iq->dp->auth_dp) {
2209                 /* we wanted to fallback, but had no delegpt, only the
2210                  * auth zone generated delegpt, create an actual one */
2211                 iq->auth_zone_avoid = 1;
2212                 return next_state(iq, INIT_REQUEST_STATE);
2213         }
2214         /* but mostly, fallback==1 (like, when no such auth zone exists)
2215          * and we continue with lookups */
2216
2217         tf_policy = 0;
2218         /* < not <=, because although the array is large enough for <=, the
2219          * generated query will immediately be discarded due to depth and
2220          * that servfail is cached, which is not good as opportunism goes. */
2221         if(iq->depth < ie->max_dependency_depth
2222                 && iq->sent_count < TARGET_FETCH_STOP) {
2223                 tf_policy = ie->target_fetch_policy[iq->depth];
2224         }
2225
2226         /* if in 0x20 fallback get as many targets as possible */
2227         if(iq->caps_fallback) {
2228                 int extra = 0;
2229                 size_t naddr, nres, navail;
2230                 if(!query_for_targets(qstate, iq, ie, id, -1, &extra)) {
2231                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2232                 }
2233                 iq->num_target_queries += extra;
2234                 target_count_increase(iq, extra);
2235                 if(iq->num_target_queries > 0) {
2236                         /* wait to get all targets, we want to try em */
2237                         verbose(VERB_ALGO, "wait for all targets for fallback");
2238                         qstate->ext_state[id] = module_wait_reply;
2239                         return 0;
2240                 }
2241                 /* did we do enough fallback queries already? */
2242                 delegpt_count_addr(iq->dp, &naddr, &nres, &navail);
2243                 /* the current caps_server is the number of fallbacks sent.
2244                  * the original query is one that matched too, so we have
2245                  * caps_server+1 number of matching queries now */
2246                 if(iq->caps_server+1 >= naddr*3 ||
2247                         iq->caps_server*2+2 >= MAX_SENT_COUNT) {
2248                         /* *2 on sentcount check because ipv6 may fail */
2249                         /* we're done, process the response */
2250                         verbose(VERB_ALGO, "0x20 fallback had %d responses "
2251                                 "match for %d wanted, done.",
2252                                 (int)iq->caps_server+1, (int)naddr*3);
2253                         iq->response = iq->caps_response;
2254                         iq->caps_fallback = 0;
2255                         iter_dec_attempts(iq->dp, 3); /* space for fallback */
2256                         iq->num_current_queries++; /* RespState decrements it*/
2257                         iq->referral_count++; /* make sure we don't loop */
2258                         iq->sent_count = 0;
2259                         iq->state = QUERY_RESP_STATE;
2260                         return 1;
2261                 }
2262                 verbose(VERB_ALGO, "0x20 fallback number %d",
2263                         (int)iq->caps_server);
2264
2265         /* if there is a policy to fetch missing targets
2266          * opportunistically, do it. we rely on the fact that once a
2267          * query (or queries) for a missing name have been issued,
2268          * they will not show up again. */
2269         } else if(tf_policy != 0) {
2270                 int extra = 0;
2271                 verbose(VERB_ALGO, "attempt to get extra %d targets",
2272                         tf_policy);
2273                 (void)query_for_targets(qstate, iq, ie, id, tf_policy, &extra);
2274                 /* errors ignored, these targets are not strictly necessary for
2275                  * this result, we do not have to reply with SERVFAIL */
2276                 iq->num_target_queries += extra;
2277                 target_count_increase(iq, extra);
2278         }
2279
2280         /* Add the current set of unused targets to our queue. */
2281         delegpt_add_unused_targets(iq->dp);
2282
2283         /* Select the next usable target, filtering out unsuitable targets. */
2284         target = iter_server_selection(ie, qstate->env, iq->dp,
2285                 iq->dp->name, iq->dp->namelen, iq->qchase.qtype,
2286                 &iq->dnssec_lame_query, &iq->chase_to_rd,
2287                 iq->num_target_queries, qstate->blacklist,
2288                 qstate->prefetch_leeway);
2289
2290         /* If no usable target was selected... */
2291         if(!target) {
2292                 /* Here we distinguish between three states: generate a new
2293                  * target query, just wait, or quit (with a SERVFAIL).
2294                  * We have the following information: number of active
2295                  * target queries, number of active current queries,
2296                  * the presence of missing targets at this delegation
2297                  * point, and the given query target policy. */
2298
2299                 /* Check for the wait condition. If this is true, then
2300                  * an action must be taken. */
2301                 if(iq->num_target_queries==0 && iq->num_current_queries==0) {
2302                         /* If there is nothing to wait for, then we need
2303                          * to distinguish between generating (a) new target
2304                          * query, or failing. */
2305                         if(delegpt_count_missing_targets(iq->dp) > 0) {
2306                                 int qs = 0;
2307                                 verbose(VERB_ALGO, "querying for next "
2308                                         "missing target");
2309                                 if(!query_for_targets(qstate, iq, ie, id,
2310                                         1, &qs)) {
2311                                         return error_response(qstate, id,
2312                                                 LDNS_RCODE_SERVFAIL);
2313                                 }
2314                                 if(qs == 0 &&
2315                                    delegpt_count_missing_targets(iq->dp) == 0){
2316                                         /* it looked like there were missing
2317                                          * targets, but they did not turn up.
2318                                          * Try the bad choices again (if any),
2319                                          * when we get back here missing==0,
2320                                          * so this is not a loop. */
2321                                         return 1;
2322                                 }
2323                                 iq->num_target_queries += qs;
2324                                 target_count_increase(iq, qs);
2325                         }
2326                         /* Since a target query might have been made, we
2327                          * need to check again. */
2328                         if(iq->num_target_queries == 0) {
2329                                 /* if in capsforid fallback, instead of last
2330                                  * resort, we agree with the current reply
2331                                  * we have (if any) (our count of addrs bad)*/
2332                                 if(iq->caps_fallback && iq->caps_reply) {
2333                                         /* we're done, process the response */
2334                                         verbose(VERB_ALGO, "0x20 fallback had %d responses, "
2335                                                 "but no more servers except "
2336                                                 "last resort, done.",
2337                                                 (int)iq->caps_server+1);
2338                                         iq->response = iq->caps_response;
2339                                         iq->caps_fallback = 0;
2340                                         iter_dec_attempts(iq->dp, 3); /* space for fallback */
2341                                         iq->num_current_queries++; /* RespState decrements it*/
2342                                         iq->referral_count++; /* make sure we don't loop */
2343                                         iq->sent_count = 0;
2344                                         iq->state = QUERY_RESP_STATE;
2345                                         return 1;
2346                                 }
2347                                 return processLastResort(qstate, iq, ie, id);
2348                         }
2349                 }
2350
2351                 /* otherwise, we have no current targets, so submerge
2352                  * until one of the target or direct queries return. */
2353                 if(iq->num_target_queries>0 && iq->num_current_queries>0) {
2354                         verbose(VERB_ALGO, "no current targets -- waiting "
2355                                 "for %d targets to resolve or %d outstanding"
2356                                 " queries to respond", iq->num_target_queries,
2357                                 iq->num_current_queries);
2358                         qstate->ext_state[id] = module_wait_reply;
2359                 } else if(iq->num_target_queries>0) {
2360                         verbose(VERB_ALGO, "no current targets -- waiting "
2361                                 "for %d targets to resolve.",
2362                                 iq->num_target_queries);
2363                         qstate->ext_state[id] = module_wait_subquery;
2364                 } else {
2365                         verbose(VERB_ALGO, "no current targets -- waiting "
2366                                 "for %d outstanding queries to respond.",
2367                                 iq->num_current_queries);
2368                         qstate->ext_state[id] = module_wait_reply;
2369                 }
2370                 return 0;
2371         }
2372
2373         /* if not forwarding, check ratelimits per delegationpoint name */
2374         if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok) {
2375                 if(!infra_ratelimit_inc(qstate->env->infra_cache, iq->dp->name,
2376                         iq->dp->namelen, *qstate->env->now)) {
2377                         lock_basic_lock(&ie->queries_ratelimit_lock);
2378                         ie->num_queries_ratelimited++;
2379                         lock_basic_unlock(&ie->queries_ratelimit_lock);
2380                         verbose(VERB_ALGO, "query exceeded ratelimits");
2381                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2382                 }
2383         }
2384
2385         /* We have a valid target. */
2386         if(verbosity >= VERB_QUERY) {
2387                 log_query_info(VERB_QUERY, "sending query:", &iq->qinfo_out);
2388                 log_name_addr(VERB_QUERY, "sending to target:", iq->dp->name,
2389                         &target->addr, target->addrlen);
2390                 verbose(VERB_ALGO, "dnssec status: %s%s",
2391                         iq->dnssec_expected?"expected": "not expected",
2392                         iq->dnssec_lame_query?" but lame_query anyway": "");
2393         }
2394         fptr_ok(fptr_whitelist_modenv_send_query(qstate->env->send_query));
2395         outq = (*qstate->env->send_query)(&iq->qinfo_out,
2396                 iq->chase_flags | (iq->chase_to_rd?BIT_RD:0),
2397                 /* unset CD if to forwarder(RD set) and not dnssec retry
2398                  * (blacklist nonempty) and no trust-anchors are configured
2399                  * above the qname or on the first attempt when dnssec is on */
2400                 EDNS_DO| ((iq->chase_to_rd||(iq->chase_flags&BIT_RD)!=0)&&
2401                 !qstate->blacklist&&(!iter_qname_indicates_dnssec(qstate->env,
2402                 &iq->qinfo_out)||target->attempts==1)?0:BIT_CD),
2403                 iq->dnssec_expected, iq->caps_fallback || is_caps_whitelisted(
2404                 ie, iq), &target->addr, target->addrlen,
2405                 iq->dp->name, iq->dp->namelen,
2406                 (iq->dp->ssl_upstream || qstate->env->cfg->ssl_upstream),
2407                 target->tls_auth_name, qstate);
2408         if(!outq) {
2409                 log_addr(VERB_DETAIL, "error sending query to auth server",
2410                         &target->addr, target->addrlen);
2411                 if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok)
2412                     infra_ratelimit_dec(qstate->env->infra_cache, iq->dp->name,
2413                         iq->dp->namelen, *qstate->env->now);
2414                 if(qstate->env->cfg->qname_minimisation)
2415                         iq->minimisation_state = SKIP_MINIMISE_STATE;
2416                 return next_state(iq, QUERYTARGETS_STATE);
2417         }
2418         outbound_list_insert(&iq->outlist, outq);
2419         iq->num_current_queries++;
2420         iq->sent_count++;
2421         qstate->ext_state[id] = module_wait_reply;
2422
2423         return 0;
2424 }
2425
2426 /** find NS rrset in given list */
2427 static struct ub_packed_rrset_key*
2428 find_NS(struct reply_info* rep, size_t from, size_t to)
2429 {
2430         size_t i;
2431         for(i=from; i<to; i++) {
2432                 if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NS)
2433                         return rep->rrsets[i];
2434         }
2435         return NULL;
2436 }
2437
2438
2439 /**
2440  * Process the query response. All queries end up at this state first. This
2441  * process generally consists of analyzing the response and routing the
2442  * event to the next state (either bouncing it back to a request state, or
2443  * terminating the processing for this event).
2444  *
2445  * @param qstate: query state.
2446  * @param iq: iterator query state.
2447  * @param id: module id.
2448  * @return true if the event requires more immediate processing, false if
2449  *         not. This is generally only true when forwarding the request to
2450  *         the final state (i.e., on answer).
2451  */
2452 static int
2453 processQueryResponse(struct module_qstate* qstate, struct iter_qstate* iq,
2454         int id)
2455 {
2456         int dnsseclame = 0;
2457         enum response_type type;
2458         iq->num_current_queries--;
2459
2460         if(!inplace_cb_query_response_call(qstate->env, qstate, iq->response))
2461                 log_err("unable to call query_response callback");
2462
2463         if(iq->response == NULL) {
2464                 /* Don't increment qname when QNAME minimisation is enabled */
2465                 if(qstate->env->cfg->qname_minimisation) {
2466                         iq->minimise_timeout_count++;
2467                         iq->minimisation_state = SKIP_MINIMISE_STATE;
2468                 }
2469                 iq->chase_to_rd = 0;
2470                 iq->dnssec_lame_query = 0;
2471                 verbose(VERB_ALGO, "query response was timeout");
2472                 return next_state(iq, QUERYTARGETS_STATE);
2473         }
2474         type = response_type_from_server(
2475                 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd),
2476                 iq->response, &iq->qinfo_out, iq->dp);
2477         iq->chase_to_rd = 0;
2478         if(type == RESPONSE_TYPE_REFERRAL && (iq->chase_flags&BIT_RD) &&
2479                 !iq->auth_zone_response) {
2480                 /* When forwarding (RD bit is set), we handle referrals
2481                  * differently. No queries should be sent elsewhere */
2482                 type = RESPONSE_TYPE_ANSWER;
2483         }
2484         if(!qstate->env->cfg->disable_dnssec_lame_check && iq->dnssec_expected
2485                 && !iq->dnssec_lame_query &&
2486                 !(iq->chase_flags&BIT_RD)
2487                 && iq->sent_count < DNSSEC_LAME_DETECT_COUNT
2488                 && type != RESPONSE_TYPE_LAME
2489                 && type != RESPONSE_TYPE_REC_LAME
2490                 && type != RESPONSE_TYPE_THROWAWAY
2491                 && type != RESPONSE_TYPE_UNTYPED) {
2492                 /* a possible answer, see if it is missing DNSSEC */
2493                 /* but not when forwarding, so we dont mark fwder lame */
2494                 if(!iter_msg_has_dnssec(iq->response)) {
2495                         /* Mark this address as dnsseclame in this dp,
2496                          * because that will make serverselection disprefer
2497                          * it, but also, once it is the only final option,
2498                          * use dnssec-lame-bypass if it needs to query there.*/
2499                         if(qstate->reply) {
2500                                 struct delegpt_addr* a = delegpt_find_addr(
2501                                         iq->dp, &qstate->reply->addr,
2502                                         qstate->reply->addrlen);
2503                                 if(a) a->dnsseclame = 1;
2504                         }
2505                         /* test the answer is from the zone we expected,
2506                          * otherwise, (due to parent,child on same server), we
2507                          * might mark the server,zone lame inappropriately */
2508                         if(!iter_msg_from_zone(iq->response, iq->dp, type,
2509                                 iq->qchase.qclass))
2510                                 qstate->reply = NULL;
2511                         type = RESPONSE_TYPE_LAME;
2512                         dnsseclame = 1;
2513                 }
2514         } else iq->dnssec_lame_query = 0;
2515         /* see if referral brings us close to the target */
2516         if(type == RESPONSE_TYPE_REFERRAL) {
2517                 struct ub_packed_rrset_key* ns = find_NS(
2518                         iq->response->rep, iq->response->rep->an_numrrsets,
2519                         iq->response->rep->an_numrrsets
2520                         + iq->response->rep->ns_numrrsets);
2521                 if(!ns) ns = find_NS(iq->response->rep, 0,
2522                                 iq->response->rep->an_numrrsets);
2523                 if(!ns || !dname_strict_subdomain_c(ns->rk.dname, iq->dp->name)
2524                         || !dname_subdomain_c(iq->qchase.qname, ns->rk.dname)){
2525                         verbose(VERB_ALGO, "bad referral, throwaway");
2526                         type = RESPONSE_TYPE_THROWAWAY;
2527                 } else
2528                         iter_scrub_ds(iq->response, ns, iq->dp->name);
2529         } else iter_scrub_ds(iq->response, NULL, NULL);
2530         if(type == RESPONSE_TYPE_THROWAWAY &&
2531                 FLAGS_GET_RCODE(iq->response->rep->flags) == LDNS_RCODE_YXDOMAIN) {
2532                 /* YXDOMAIN is a permanent error, no need to retry */
2533                 type = RESPONSE_TYPE_ANSWER;
2534         }
2535         if(type == RESPONSE_TYPE_CNAME && iq->response->rep->an_numrrsets >= 1
2536                 && ntohs(iq->response->rep->rrsets[0]->rk.type) == LDNS_RR_TYPE_DNAME) {
2537                 uint8_t* sname = NULL;
2538                 size_t snamelen = 0;
2539                 get_cname_target(iq->response->rep->rrsets[0], &sname,
2540                         &snamelen);
2541                 if(snamelen && dname_subdomain_c(sname, iq->response->rep->rrsets[0]->rk.dname)) {
2542                         /* DNAME to a subdomain loop; do not recurse */
2543                         type = RESPONSE_TYPE_ANSWER;
2544                 }
2545         }
2546
2547         /* handle each of the type cases */
2548         if(type == RESPONSE_TYPE_ANSWER) {
2549                 /* ANSWER type responses terminate the query algorithm,
2550                  * so they sent on their */
2551                 if(verbosity >= VERB_DETAIL) {
2552                         verbose(VERB_DETAIL, "query response was %s",
2553                                 FLAGS_GET_RCODE(iq->response->rep->flags)
2554                                 ==LDNS_RCODE_NXDOMAIN?"NXDOMAIN ANSWER":
2555                                 (iq->response->rep->an_numrrsets?"ANSWER":
2556                                 "nodata ANSWER"));
2557                 }
2558                 /* if qtype is DS, check we have the right level of answer,
2559                  * like grandchild answer but we need the middle, reject it */
2560                 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
2561                         && !(iq->chase_flags&BIT_RD)
2562                         && iter_ds_toolow(iq->response, iq->dp)
2563                         && iter_dp_cangodown(&iq->qchase, iq->dp)) {
2564                         /* close down outstanding requests to be discarded */
2565                         outbound_list_clear(&iq->outlist);
2566                         iq->num_current_queries = 0;
2567                         fptr_ok(fptr_whitelist_modenv_detach_subs(
2568                                 qstate->env->detach_subs));
2569                         (*qstate->env->detach_subs)(qstate);
2570                         iq->num_target_queries = 0;
2571                         return processDSNSFind(qstate, iq, id);
2572                 }
2573                 if(!qstate->no_cache_store)
2574                         iter_dns_store(qstate->env, &iq->response->qinfo,
2575                                 iq->response->rep, 0, qstate->prefetch_leeway,
2576                                 iq->dp&&iq->dp->has_parent_side_NS,
2577                                 qstate->region, qstate->query_flags);
2578                 /* close down outstanding requests to be discarded */
2579                 outbound_list_clear(&iq->outlist);
2580                 iq->num_current_queries = 0;
2581                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2582                         qstate->env->detach_subs));
2583                 (*qstate->env->detach_subs)(qstate);
2584                 iq->num_target_queries = 0;
2585                 if(qstate->reply)
2586                         sock_list_insert(&qstate->reply_origin,
2587                                 &qstate->reply->addr, qstate->reply->addrlen,
2588                                 qstate->region);
2589                 if(iq->minimisation_state != DONOT_MINIMISE_STATE) {
2590                         if(FLAGS_GET_RCODE(iq->response->rep->flags) !=
2591                                 LDNS_RCODE_NOERROR) {
2592                                 if(qstate->env->cfg->qname_minimisation_strict)
2593                                         return final_state(iq);
2594                                 /* Best effort qname-minimisation.
2595                                  * Stop minimising and send full query when
2596                                  * RCODE is not NOERROR. */
2597                                 iq->minimisation_state = DONOT_MINIMISE_STATE;
2598                         }
2599                         if(FLAGS_GET_RCODE(iq->response->rep->flags) ==
2600                                 LDNS_RCODE_NXDOMAIN) {
2601                                 /* Stop resolving when NXDOMAIN is DNSSEC
2602                                  * signed. Based on assumption that nameservers
2603                                  * serving signed zones do not return NXDOMAIN
2604                                  * for empty-non-terminals. */
2605                                 if(iq->dnssec_expected)
2606                                         return final_state(iq);
2607                                 /* Make subrequest to validate intermediate
2608                                  * NXDOMAIN if harden-below-nxdomain is
2609                                  * enabled. */
2610                                 if(qstate->env->cfg->harden_below_nxdomain) {
2611                                         struct module_qstate* subq = NULL;
2612                                         log_query_info(VERB_QUERY,
2613                                                 "schedule NXDOMAIN validation:",
2614                                                 &iq->response->qinfo);
2615                                         if(!generate_sub_request(
2616                                                 iq->response->qinfo.qname,
2617                                                 iq->response->qinfo.qname_len,
2618                                                 iq->response->qinfo.qtype,
2619                                                 iq->response->qinfo.qclass,
2620                                                 qstate, id, iq,
2621                                                 INIT_REQUEST_STATE,
2622                                                 FINISHED_STATE, &subq, 1))
2623                                                 verbose(VERB_ALGO,
2624                                                 "could not validate NXDOMAIN "
2625                                                 "response");
2626                                 }
2627                         }
2628                         return next_state(iq, QUERYTARGETS_STATE);
2629                 }
2630                 return final_state(iq);
2631         } else if(type == RESPONSE_TYPE_REFERRAL) {
2632                 /* REFERRAL type responses get a reset of the
2633                  * delegation point, and back to the QUERYTARGETS_STATE. */
2634                 verbose(VERB_DETAIL, "query response was REFERRAL");
2635
2636                 if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok) {
2637                         /* we have a referral, no ratelimit, we can send
2638                          * our queries to the given name */
2639                         infra_ratelimit_dec(qstate->env->infra_cache,
2640                                 iq->dp->name, iq->dp->namelen,
2641                                 *qstate->env->now);
2642                 }
2643
2644                 /* if hardened, only store referral if we asked for it */
2645                 if(!qstate->no_cache_store &&
2646                 (!qstate->env->cfg->harden_referral_path ||
2647                     (  qstate->qinfo.qtype == LDNS_RR_TYPE_NS
2648                         && (qstate->query_flags&BIT_RD)
2649                         && !(qstate->query_flags&BIT_CD)
2650                            /* we know that all other NS rrsets are scrubbed
2651                             * away, thus on referral only one is left.
2652                             * see if that equals the query name... */
2653                         && ( /* auth section, but sometimes in answer section*/
2654                           reply_find_rrset_section_ns(iq->response->rep,
2655                                 iq->qchase.qname, iq->qchase.qname_len,
2656                                 LDNS_RR_TYPE_NS, iq->qchase.qclass)
2657                           || reply_find_rrset_section_an(iq->response->rep,
2658                                 iq->qchase.qname, iq->qchase.qname_len,
2659                                 LDNS_RR_TYPE_NS, iq->qchase.qclass)
2660                           )
2661                     ))) {
2662                         /* Store the referral under the current query */
2663                         /* no prefetch-leeway, since its not the answer */
2664                         iter_dns_store(qstate->env, &iq->response->qinfo,
2665                                 iq->response->rep, 1, 0, 0, NULL, 0);
2666                         if(iq->store_parent_NS)
2667                                 iter_store_parentside_NS(qstate->env,
2668                                         iq->response->rep);
2669                         if(qstate->env->neg_cache)
2670                                 val_neg_addreferral(qstate->env->neg_cache,
2671                                         iq->response->rep, iq->dp->name);
2672                 }
2673                 /* store parent-side-in-zone-glue, if directly queried for */
2674                 if(!qstate->no_cache_store && iq->query_for_pside_glue
2675                         && !iq->pside_glue) {
2676                                 iq->pside_glue = reply_find_rrset(iq->response->rep,
2677                                         iq->qchase.qname, iq->qchase.qname_len,
2678                                         iq->qchase.qtype, iq->qchase.qclass);
2679                                 if(iq->pside_glue) {
2680                                         log_rrset_key(VERB_ALGO, "found parent-side "
2681                                                 "glue", iq->pside_glue);
2682                                         iter_store_parentside_rrset(qstate->env,
2683                                                 iq->pside_glue);
2684                                 }
2685                 }
2686
2687                 /* Reset the event state, setting the current delegation
2688                  * point to the referral. */
2689                 iq->deleg_msg = iq->response;
2690                 iq->dp = delegpt_from_message(iq->response, qstate->region);
2691                 if (qstate->env->cfg->qname_minimisation)
2692                         iq->minimisation_state = INIT_MINIMISE_STATE;
2693                 if(!iq->dp)
2694                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2695                 if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
2696                         qstate->region, iq->dp))
2697                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2698                 if(iq->store_parent_NS && query_dname_compare(iq->dp->name,
2699                         iq->store_parent_NS->name) == 0)
2700                         iter_merge_retry_counts(iq->dp, iq->store_parent_NS);
2701                 delegpt_log(VERB_ALGO, iq->dp);
2702                 /* Count this as a referral. */
2703                 iq->referral_count++;
2704                 iq->sent_count = 0;
2705                 /* see if the next dp is a trust anchor, or a DS was sent
2706                  * along, indicating dnssec is expected for next zone */
2707                 iq->dnssec_expected = iter_indicates_dnssec(qstate->env,
2708                         iq->dp, iq->response, iq->qchase.qclass);
2709                 /* if dnssec, validating then also fetch the key for the DS */
2710                 if(iq->dnssec_expected && qstate->env->cfg->prefetch_key &&
2711                         !(qstate->query_flags&BIT_CD))
2712                         generate_dnskey_prefetch(qstate, iq, id);
2713
2714                 /* spawn off NS and addr to auth servers for the NS we just
2715                  * got in the referral. This gets authoritative answer
2716                  * (answer section trust level) rrset.
2717                  * right after, we detach the subs, answer goes to cache. */
2718                 if(qstate->env->cfg->harden_referral_path)
2719                         generate_ns_check(qstate, iq, id);
2720
2721                 /* stop current outstanding queries.
2722                  * FIXME: should the outstanding queries be waited for and
2723                  * handled? Say by a subquery that inherits the outbound_entry.
2724                  */
2725                 outbound_list_clear(&iq->outlist);
2726                 iq->num_current_queries = 0;
2727                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2728                         qstate->env->detach_subs));
2729                 (*qstate->env->detach_subs)(qstate);
2730                 iq->num_target_queries = 0;
2731                 verbose(VERB_ALGO, "cleared outbound list for next round");
2732                 return next_state(iq, QUERYTARGETS_STATE);
2733         } else if(type == RESPONSE_TYPE_CNAME) {
2734                 uint8_t* sname = NULL;
2735                 size_t snamelen = 0;
2736                 /* CNAME type responses get a query restart (i.e., get a
2737                  * reset of the query state and go back to INIT_REQUEST_STATE).
2738                  */
2739                 verbose(VERB_DETAIL, "query response was CNAME");
2740                 if(verbosity >= VERB_ALGO)
2741                         log_dns_msg("cname msg", &iq->response->qinfo,
2742                                 iq->response->rep);
2743                 /* if qtype is DS, check we have the right level of answer,
2744                  * like grandchild answer but we need the middle, reject it */
2745                 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
2746                         && !(iq->chase_flags&BIT_RD)
2747                         && iter_ds_toolow(iq->response, iq->dp)
2748                         && iter_dp_cangodown(&iq->qchase, iq->dp)) {
2749                         outbound_list_clear(&iq->outlist);
2750                         iq->num_current_queries = 0;
2751                         fptr_ok(fptr_whitelist_modenv_detach_subs(
2752                                 qstate->env->detach_subs));
2753                         (*qstate->env->detach_subs)(qstate);
2754                         iq->num_target_queries = 0;
2755                         return processDSNSFind(qstate, iq, id);
2756                 }
2757                 /* Process the CNAME response. */
2758                 if(!handle_cname_response(qstate, iq, iq->response,
2759                         &sname, &snamelen))
2760                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2761                 /* cache the CNAME response under the current query */
2762                 /* NOTE : set referral=1, so that rrsets get stored but not
2763                  * the partial query answer (CNAME only). */
2764                 /* prefetchleeway applied because this updates answer parts */
2765                 if(!qstate->no_cache_store)
2766                         iter_dns_store(qstate->env, &iq->response->qinfo,
2767                                 iq->response->rep, 1, qstate->prefetch_leeway,
2768                                 iq->dp&&iq->dp->has_parent_side_NS, NULL,
2769                                 qstate->query_flags);
2770                 /* set the current request's qname to the new value. */
2771                 iq->qchase.qname = sname;
2772                 iq->qchase.qname_len = snamelen;
2773                 /* Clear the query state, since this is a query restart. */
2774                 iq->deleg_msg = NULL;
2775                 iq->dp = NULL;
2776                 iq->dsns_point = NULL;
2777                 iq->auth_zone_response = 0;
2778                 iq->sent_count = 0;
2779                 if(iq->minimisation_state != MINIMISE_STATE)
2780                         /* Only count as query restart when it is not an extra
2781                          * query as result of qname minimisation. */
2782                         iq->query_restart_count++;
2783                 if(qstate->env->cfg->qname_minimisation)
2784                         iq->minimisation_state = INIT_MINIMISE_STATE;
2785
2786                 /* stop current outstanding queries.
2787                  * FIXME: should the outstanding queries be waited for and
2788                  * handled? Say by a subquery that inherits the outbound_entry.
2789                  */
2790                 outbound_list_clear(&iq->outlist);
2791                 iq->num_current_queries = 0;
2792                 fptr_ok(fptr_whitelist_modenv_detach_subs(
2793                         qstate->env->detach_subs));
2794                 (*qstate->env->detach_subs)(qstate);
2795                 iq->num_target_queries = 0;
2796                 if(qstate->reply)
2797                         sock_list_insert(&qstate->reply_origin,
2798                                 &qstate->reply->addr, qstate->reply->addrlen,
2799                                 qstate->region);
2800                 verbose(VERB_ALGO, "cleared outbound list for query restart");
2801                 /* go to INIT_REQUEST_STATE for new qname. */
2802                 return next_state(iq, INIT_REQUEST_STATE);
2803         } else if(type == RESPONSE_TYPE_LAME) {
2804                 /* Cache the LAMEness. */
2805                 verbose(VERB_DETAIL, "query response was %sLAME",
2806                         dnsseclame?"DNSSEC ":"");
2807                 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) {
2808                         log_err("mark lame: mismatch in qname and dpname");
2809                         /* throwaway this reply below */
2810                 } else if(qstate->reply) {
2811                         /* need addr for lameness cache, but we may have
2812                          * gotten this from cache, so test to be sure */
2813                         if(!infra_set_lame(qstate->env->infra_cache,
2814                                 &qstate->reply->addr, qstate->reply->addrlen,
2815                                 iq->dp->name, iq->dp->namelen,
2816                                 *qstate->env->now, dnsseclame, 0,
2817                                 iq->qchase.qtype))
2818                                 log_err("mark host lame: out of memory");
2819                 }
2820         } else if(type == RESPONSE_TYPE_REC_LAME) {
2821                 /* Cache the LAMEness. */
2822                 verbose(VERB_DETAIL, "query response REC_LAME: "
2823                         "recursive but not authoritative server");
2824                 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) {
2825                         log_err("mark rec_lame: mismatch in qname and dpname");
2826                         /* throwaway this reply below */
2827                 } else if(qstate->reply) {
2828                         /* need addr for lameness cache, but we may have
2829                          * gotten this from cache, so test to be sure */
2830                         verbose(VERB_DETAIL, "mark as REC_LAME");
2831                         if(!infra_set_lame(qstate->env->infra_cache,
2832                                 &qstate->reply->addr, qstate->reply->addrlen,
2833                                 iq->dp->name, iq->dp->namelen,
2834                                 *qstate->env->now, 0, 1, iq->qchase.qtype))
2835                                 log_err("mark host lame: out of memory");
2836                 }
2837         } else if(type == RESPONSE_TYPE_THROWAWAY) {
2838                 /* LAME and THROWAWAY responses are handled the same way.
2839                  * In this case, the event is just sent directly back to
2840                  * the QUERYTARGETS_STATE without resetting anything,
2841                  * because, clearly, the next target must be tried. */
2842                 verbose(VERB_DETAIL, "query response was THROWAWAY");
2843         } else {
2844                 log_warn("A query response came back with an unknown type: %d",
2845                         (int)type);
2846         }
2847
2848         /* LAME, THROWAWAY and "unknown" all end up here.
2849          * Recycle to the QUERYTARGETS state to hopefully try a
2850          * different target. */
2851         if (qstate->env->cfg->qname_minimisation &&
2852                 !qstate->env->cfg->qname_minimisation_strict)
2853                 iq->minimisation_state = DONOT_MINIMISE_STATE;
2854         if(iq->auth_zone_response) {
2855                 /* can we fallback? */
2856                 iq->auth_zone_response = 0;
2857                 if(!auth_zones_can_fallback(qstate->env->auth_zones,
2858                         iq->dp->name, iq->dp->namelen, qstate->qinfo.qclass)) {
2859                         verbose(VERB_ALGO, "auth zone response bad, and no"
2860                                 " fallback possible, servfail");
2861                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2862                 }
2863                 verbose(VERB_ALGO, "auth zone response was bad, "
2864                         "fallback enabled");
2865                 iq->auth_zone_avoid = 1;
2866                 if(iq->dp->auth_dp) {
2867                         /* we are using a dp for the auth zone, with no
2868                          * nameservers, get one first */
2869                         iq->dp = NULL;
2870                         return next_state(iq, INIT_REQUEST_STATE);
2871                 }
2872         }
2873         return next_state(iq, QUERYTARGETS_STATE);
2874 }
2875
2876 /**
2877  * Return priming query results to interested super querystates.
2878  *
2879  * Sets the delegation point and delegation message (not nonRD queries).
2880  * This is a callback from walk_supers.
2881  *
2882  * @param qstate: priming query state that finished.
2883  * @param id: module id.
2884  * @param forq: the qstate for which priming has been done.
2885  */
2886 static void
2887 prime_supers(struct module_qstate* qstate, int id, struct module_qstate* forq)
2888 {
2889         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
2890         struct delegpt* dp = NULL;
2891
2892         log_assert(qstate->is_priming || foriq->wait_priming_stub);
2893         log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR);
2894         /* Convert our response to a delegation point */
2895         dp = delegpt_from_message(qstate->return_msg, forq->region);
2896         if(!dp) {
2897                 /* if there is no convertable delegation point, then
2898                  * the ANSWER type was (presumably) a negative answer. */
2899                 verbose(VERB_ALGO, "prime response was not a positive "
2900                         "ANSWER; failing");
2901                 foriq->dp = NULL;
2902                 foriq->state = QUERYTARGETS_STATE;
2903                 return;
2904         }
2905
2906         log_query_info(VERB_DETAIL, "priming successful for", &qstate->qinfo);
2907         delegpt_log(VERB_ALGO, dp);
2908         foriq->dp = dp;
2909         foriq->deleg_msg = dns_copy_msg(qstate->return_msg, forq->region);
2910         if(!foriq->deleg_msg) {
2911                 log_err("copy prime response: out of memory");
2912                 foriq->dp = NULL;
2913                 foriq->state = QUERYTARGETS_STATE;
2914                 return;
2915         }
2916
2917         /* root priming responses go to init stage 2, priming stub
2918          * responses to to stage 3. */
2919         if(foriq->wait_priming_stub) {
2920                 foriq->state = INIT_REQUEST_3_STATE;
2921                 foriq->wait_priming_stub = 0;
2922         } else  foriq->state = INIT_REQUEST_2_STATE;
2923         /* because we are finished, the parent will be reactivated */
2924 }
2925
2926 /**
2927  * This handles the response to a priming query. This is used to handle both
2928  * root and stub priming responses. This is basically the equivalent of the
2929  * QUERY_RESP_STATE, but will not handle CNAME responses and will treat
2930  * REFERRALs as ANSWERS. It will also update and reactivate the originating
2931  * event.
2932  *
2933  * @param qstate: query state.
2934  * @param id: module id.
2935  * @return true if the event needs more immediate processing, false if not.
2936  *         This state always returns false.
2937  */
2938 static int
2939 processPrimeResponse(struct module_qstate* qstate, int id)
2940 {
2941         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
2942         enum response_type type;
2943         iq->response->rep->flags &= ~(BIT_RD|BIT_RA); /* ignore rec-lame */
2944         type = response_type_from_server(
2945                 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd),
2946                 iq->response, &iq->qchase, iq->dp);
2947         if(type == RESPONSE_TYPE_ANSWER) {
2948                 qstate->return_rcode = LDNS_RCODE_NOERROR;
2949                 qstate->return_msg = iq->response;
2950         } else {
2951                 qstate->return_rcode = LDNS_RCODE_SERVFAIL;
2952                 qstate->return_msg = NULL;
2953         }
2954
2955         /* validate the root or stub after priming (if enabled).
2956          * This is the same query as the prime query, but with validation.
2957          * Now that we are primed, the additional queries that validation
2958          * may need can be resolved, such as DLV. */
2959         if(qstate->env->cfg->harden_referral_path) {
2960                 struct module_qstate* subq = NULL;
2961                 log_nametypeclass(VERB_ALGO, "schedule prime validation",
2962                         qstate->qinfo.qname, qstate->qinfo.qtype,
2963                         qstate->qinfo.qclass);
2964                 if(!generate_sub_request(qstate->qinfo.qname,
2965                         qstate->qinfo.qname_len, qstate->qinfo.qtype,
2966                         qstate->qinfo.qclass, qstate, id, iq,
2967                         INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) {
2968                         verbose(VERB_ALGO, "could not generate prime check");
2969                 }
2970                 generate_a_aaaa_check(qstate, iq, id);
2971         }
2972
2973         /* This event is finished. */
2974         qstate->ext_state[id] = module_finished;
2975         return 0;
2976 }
2977
2978 /**
2979  * Do final processing on responses to target queries. Events reach this
2980  * state after the iterative resolution algorithm terminates. This state is
2981  * responsible for reactivating the original event, and housekeeping related
2982  * to received target responses (caching, updating the current delegation
2983  * point, etc).
2984  * Callback from walk_supers for every super state that is interested in
2985  * the results from this query.
2986  *
2987  * @param qstate: query state.
2988  * @param id: module id.
2989  * @param forq: super query state.
2990  */
2991 static void
2992 processTargetResponse(struct module_qstate* qstate, int id,
2993         struct module_qstate* forq)
2994 {
2995         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
2996         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
2997         struct ub_packed_rrset_key* rrset;
2998         struct delegpt_ns* dpns;
2999         log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR);
3000
3001         foriq->state = QUERYTARGETS_STATE;
3002         log_query_info(VERB_ALGO, "processTargetResponse", &qstate->qinfo);
3003         log_query_info(VERB_ALGO, "processTargetResponse super", &forq->qinfo);
3004
3005         /* Tell the originating event that this target query has finished
3006          * (regardless if it succeeded or not). */
3007         foriq->num_target_queries--;
3008
3009         /* check to see if parent event is still interested (in orig name).  */
3010         if(!foriq->dp) {
3011                 verbose(VERB_ALGO, "subq: parent not interested, was reset");
3012                 return; /* not interested anymore */
3013         }
3014         dpns = delegpt_find_ns(foriq->dp, qstate->qinfo.qname,
3015                         qstate->qinfo.qname_len);
3016         if(!dpns) {
3017                 /* If not interested, just stop processing this event */
3018                 verbose(VERB_ALGO, "subq: parent not interested anymore");
3019                 /* could be because parent was jostled out of the cache,
3020                    and a new identical query arrived, that does not want it*/
3021                 return;
3022         }
3023
3024         /* if iq->query_for_pside_glue then add the pside_glue (marked lame) */
3025         if(iq->pside_glue) {
3026                 /* if the pside_glue is NULL, then it could not be found,
3027                  * the done_pside is already set when created and a cache
3028                  * entry created in processFinished so nothing to do here */
3029                 log_rrset_key(VERB_ALGO, "add parentside glue to dp",
3030                         iq->pside_glue);
3031                 if(!delegpt_add_rrset(foriq->dp, forq->region,
3032                         iq->pside_glue, 1))
3033                         log_err("out of memory adding pside glue");
3034         }
3035
3036         /* This response is relevant to the current query, so we
3037          * add (attempt to add, anyway) this target(s) and reactivate
3038          * the original event.
3039          * NOTE: we could only look for the AnswerRRset if the
3040          * response type was ANSWER. */
3041         rrset = reply_find_answer_rrset(&iq->qchase, qstate->return_msg->rep);
3042         if(rrset) {
3043                 /* if CNAMEs have been followed - add new NS to delegpt. */
3044                 /* BTW. RFC 1918 says NS should not have got CNAMEs. Robust. */
3045                 if(!delegpt_find_ns(foriq->dp, rrset->rk.dname,
3046                         rrset->rk.dname_len)) {
3047                         /* if dpns->lame then set newcname ns lame too */
3048                         if(!delegpt_add_ns(foriq->dp, forq->region,
3049                                 rrset->rk.dname, dpns->lame))
3050                                 log_err("out of memory adding cnamed-ns");
3051                 }
3052                 /* if dpns->lame then set the address(es) lame too */
3053                 if(!delegpt_add_rrset(foriq->dp, forq->region, rrset,
3054                         dpns->lame))
3055                         log_err("out of memory adding targets");
3056                 verbose(VERB_ALGO, "added target response");
3057                 delegpt_log(VERB_ALGO, foriq->dp);
3058         } else {
3059                 verbose(VERB_ALGO, "iterator TargetResponse failed");
3060                 dpns->resolved = 1; /* fail the target */
3061         }
3062 }
3063
3064 /**
3065  * Process response for DS NS Find queries, that attempt to find the delegation
3066  * point where we ask the DS query from.
3067  *
3068  * @param qstate: query state.
3069  * @param id: module id.
3070  * @param forq: super query state.
3071  */
3072 static void
3073 processDSNSResponse(struct module_qstate* qstate, int id,
3074         struct module_qstate* forq)
3075 {
3076         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
3077
3078         /* if the finished (iq->response) query has no NS set: continue
3079          * up to look for the right dp; nothing to change, do DPNSstate */
3080         if(qstate->return_rcode != LDNS_RCODE_NOERROR)
3081                 return; /* seek further */
3082         /* find the NS RRset (without allowing CNAMEs) */
3083         if(!reply_find_rrset(qstate->return_msg->rep, qstate->qinfo.qname,
3084                 qstate->qinfo.qname_len, LDNS_RR_TYPE_NS,
3085                 qstate->qinfo.qclass)){
3086                 return; /* seek further */
3087         }
3088
3089         /* else, store as DP and continue at querytargets */
3090         foriq->state = QUERYTARGETS_STATE;
3091         foriq->dp = delegpt_from_message(qstate->return_msg, forq->region);
3092         if(!foriq->dp) {
3093                 log_err("out of memory in dsns dp alloc");
3094                 return; /* dp==NULL in QUERYTARGETS makes SERVFAIL */
3095         }
3096         /* success, go query the querytargets in the new dp (and go down) */
3097 }
3098
3099 /**
3100  * Process response for qclass=ANY queries for a particular class.
3101  * Append to result or error-exit.
3102  *
3103  * @param qstate: query state.
3104  * @param id: module id.
3105  * @param forq: super query state.
3106  */
3107 static void
3108 processClassResponse(struct module_qstate* qstate, int id,
3109         struct module_qstate* forq)
3110 {
3111         struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
3112         struct dns_msg* from = qstate->return_msg;
3113         log_query_info(VERB_ALGO, "processClassResponse", &qstate->qinfo);
3114         log_query_info(VERB_ALGO, "processClassResponse super", &forq->qinfo);
3115         if(qstate->return_rcode != LDNS_RCODE_NOERROR) {
3116                 /* cause servfail for qclass ANY query */
3117                 foriq->response = NULL;
3118                 foriq->state = FINISHED_STATE;
3119                 return;
3120         }
3121         /* append result */
3122         if(!foriq->response) {
3123                 /* allocate the response: copy RCODE, sec_state */
3124                 foriq->response = dns_copy_msg(from, forq->region);
3125                 if(!foriq->response) {
3126                         log_err("malloc failed for qclass ANY response");
3127                         foriq->state = FINISHED_STATE;
3128                         return;
3129                 }
3130                 foriq->response->qinfo.qclass = forq->qinfo.qclass;
3131                 /* qclass ANY does not receive the AA flag on replies */
3132                 foriq->response->rep->authoritative = 0;
3133         } else {
3134                 struct dns_msg* to = foriq->response;
3135                 /* add _from_ this response _to_ existing collection */
3136                 /* if there are records, copy RCODE */
3137                 /* lower sec_state if this message is lower */
3138                 if(from->rep->rrset_count != 0) {
3139                         size_t n = from->rep->rrset_count+to->rep->rrset_count;
3140                         struct ub_packed_rrset_key** dest, **d;
3141                         /* copy appropriate rcode */
3142                         to->rep->flags = from->rep->flags;
3143                         /* copy rrsets */
3144                         if(from->rep->rrset_count > RR_COUNT_MAX ||
3145                                 to->rep->rrset_count > RR_COUNT_MAX) {
3146                                 log_err("malloc failed (too many rrsets) in collect ANY");
3147                                 foriq->state = FINISHED_STATE;
3148                                 return; /* integer overflow protection */
3149                         }
3150                         dest = regional_alloc(forq->region, sizeof(dest[0])*n);
3151                         if(!dest) {
3152                                 log_err("malloc failed in collect ANY");
3153                                 foriq->state = FINISHED_STATE;
3154                                 return;
3155                         }
3156                         d = dest;
3157                         /* copy AN */
3158                         memcpy(dest, to->rep->rrsets, to->rep->an_numrrsets
3159                                 * sizeof(dest[0]));
3160                         dest += to->rep->an_numrrsets;
3161                         memcpy(dest, from->rep->rrsets, from->rep->an_numrrsets
3162                                 * sizeof(dest[0]));
3163                         dest += from->rep->an_numrrsets;
3164                         /* copy NS */
3165                         memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets,
3166                                 to->rep->ns_numrrsets * sizeof(dest[0]));
3167                         dest += to->rep->ns_numrrsets;
3168                         memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets,
3169                                 from->rep->ns_numrrsets * sizeof(dest[0]));
3170                         dest += from->rep->ns_numrrsets;
3171                         /* copy AR */
3172                         memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets+
3173                                 to->rep->ns_numrrsets,
3174                                 to->rep->ar_numrrsets * sizeof(dest[0]));
3175                         dest += to->rep->ar_numrrsets;
3176                         memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets+
3177                                 from->rep->ns_numrrsets,
3178                                 from->rep->ar_numrrsets * sizeof(dest[0]));
3179                         /* update counts */
3180                         to->rep->rrsets = d;
3181                         to->rep->an_numrrsets += from->rep->an_numrrsets;
3182                         to->rep->ns_numrrsets += from->rep->ns_numrrsets;
3183                         to->rep->ar_numrrsets += from->rep->ar_numrrsets;
3184                         to->rep->rrset_count = n;
3185                 }
3186                 if(from->rep->security < to->rep->security) /* lowest sec */
3187                         to->rep->security = from->rep->security;
3188                 if(from->rep->qdcount != 0) /* insert qd if appropriate */
3189                         to->rep->qdcount = from->rep->qdcount;
3190                 if(from->rep->ttl < to->rep->ttl) /* use smallest TTL */
3191                         to->rep->ttl = from->rep->ttl;
3192                 if(from->rep->prefetch_ttl < to->rep->prefetch_ttl)
3193                         to->rep->prefetch_ttl = from->rep->prefetch_ttl;
3194         }
3195         /* are we done? */
3196         foriq->num_current_queries --;
3197         if(foriq->num_current_queries == 0)
3198                 foriq->state = FINISHED_STATE;
3199 }
3200
3201 /**
3202  * Collect class ANY responses and make them into one response.  This
3203  * state is started and it creates queries for all classes (that have
3204  * root hints).  The answers are then collected.
3205  *
3206  * @param qstate: query state.
3207  * @param id: module id.
3208  * @return true if the event needs more immediate processing, false if not.
3209  */
3210 static int
3211 processCollectClass(struct module_qstate* qstate, int id)
3212 {
3213         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3214         struct module_qstate* subq;
3215         /* If qchase.qclass == 0 then send out queries for all classes.
3216          * Otherwise, do nothing (wait for all answers to arrive and the
3217          * processClassResponse to put them together, and that moves us
3218          * towards the Finished state when done. */
3219         if(iq->qchase.qclass == 0) {
3220                 uint16_t c = 0;
3221                 iq->qchase.qclass = LDNS_RR_CLASS_ANY;
3222                 while(iter_get_next_root(qstate->env->hints,
3223                         qstate->env->fwds, &c)) {
3224                         /* generate query for this class */
3225                         log_nametypeclass(VERB_ALGO, "spawn collect query",
3226                                 qstate->qinfo.qname, qstate->qinfo.qtype, c);
3227                         if(!generate_sub_request(qstate->qinfo.qname,
3228                                 qstate->qinfo.qname_len, qstate->qinfo.qtype,
3229                                 c, qstate, id, iq, INIT_REQUEST_STATE,
3230                                 FINISHED_STATE, &subq,
3231                                 (int)!(qstate->query_flags&BIT_CD))) {
3232                                 return error_response(qstate, id,
3233                                         LDNS_RCODE_SERVFAIL);
3234                         }
3235                         /* ignore subq, no special init required */
3236                         iq->num_current_queries ++;
3237                         if(c == 0xffff)
3238                                 break;
3239                         else c++;
3240                 }
3241                 /* if no roots are configured at all, return */
3242                 if(iq->num_current_queries == 0) {
3243                         verbose(VERB_ALGO, "No root hints or fwds, giving up "
3244                                 "on qclass ANY");
3245                         return error_response(qstate, id, LDNS_RCODE_REFUSED);
3246                 }
3247                 /* return false, wait for queries to return */
3248         }
3249         /* if woke up here because of an answer, wait for more answers */
3250         return 0;
3251 }
3252
3253 /**
3254  * This handles the final state for first-tier responses (i.e., responses to
3255  * externally generated queries).
3256  *
3257  * @param qstate: query state.
3258  * @param iq: iterator query state.
3259  * @param id: module id.
3260  * @return true if the event needs more processing, false if not. Since this
3261  *         is the final state for an event, it always returns false.
3262  */
3263 static int
3264 processFinished(struct module_qstate* qstate, struct iter_qstate* iq,
3265         int id)
3266 {
3267         log_query_info(VERB_QUERY, "finishing processing for",
3268                 &qstate->qinfo);
3269
3270         /* store negative cache element for parent side glue. */
3271         if(!qstate->no_cache_store && iq->query_for_pside_glue
3272                 && !iq->pside_glue)
3273                         iter_store_parentside_neg(qstate->env, &qstate->qinfo,
3274                                 iq->deleg_msg?iq->deleg_msg->rep:
3275                                 (iq->response?iq->response->rep:NULL));
3276         if(!iq->response) {
3277                 verbose(VERB_ALGO, "No response is set, servfail");
3278                 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3279         }
3280
3281         /* Make sure that the RA flag is set (since the presence of
3282          * this module means that recursion is available) */
3283         iq->response->rep->flags |= BIT_RA;
3284
3285         /* Clear the AA flag */
3286         /* FIXME: does this action go here or in some other module? */
3287         iq->response->rep->flags &= ~BIT_AA;
3288
3289         /* make sure QR flag is on */
3290         iq->response->rep->flags |= BIT_QR;
3291
3292         /* we have finished processing this query */
3293         qstate->ext_state[id] = module_finished;
3294
3295         /* TODO:  we are using a private TTL, trim the response. */
3296         /* if (mPrivateTTL > 0){IterUtils.setPrivateTTL(resp, mPrivateTTL); } */
3297
3298         /* prepend any items we have accumulated */
3299         if(iq->an_prepend_list || iq->ns_prepend_list) {
3300                 if(!iter_prepend(iq, iq->response, qstate->region)) {
3301                         log_err("prepend rrsets: out of memory");
3302                         return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3303                 }
3304                 /* reset the query name back */
3305                 iq->response->qinfo = qstate->qinfo;
3306                 /* the security state depends on the combination */
3307                 iq->response->rep->security = sec_status_unchecked;
3308                 /* store message with the finished prepended items,
3309                  * but only if we did recursion. The nonrecursion referral
3310                  * from cache does not need to be stored in the msg cache. */
3311                 if(!qstate->no_cache_store && qstate->query_flags&BIT_RD) {
3312                         iter_dns_store(qstate->env, &qstate->qinfo,
3313                                 iq->response->rep, 0, qstate->prefetch_leeway,
3314                                 iq->dp&&iq->dp->has_parent_side_NS,
3315                                 qstate->region, qstate->query_flags);
3316                 }
3317         }
3318         qstate->return_rcode = LDNS_RCODE_NOERROR;
3319         qstate->return_msg = iq->response;
3320         return 0;
3321 }
3322
3323 /*
3324  * Return priming query results to interested super querystates.
3325  *
3326  * Sets the delegation point and delegation message (not nonRD queries).
3327  * This is a callback from walk_supers.
3328  *
3329  * @param qstate: query state that finished.
3330  * @param id: module id.
3331  * @param super: the qstate to inform.
3332  */
3333 void
3334 iter_inform_super(struct module_qstate* qstate, int id,
3335         struct module_qstate* super)
3336 {
3337         if(!qstate->is_priming && super->qinfo.qclass == LDNS_RR_CLASS_ANY)
3338                 processClassResponse(qstate, id, super);
3339         else if(super->qinfo.qtype == LDNS_RR_TYPE_DS && ((struct iter_qstate*)
3340                 super->minfo[id])->state == DSNS_FIND_STATE)
3341                 processDSNSResponse(qstate, id, super);
3342         else if(qstate->return_rcode != LDNS_RCODE_NOERROR)
3343                 error_supers(qstate, id, super);
3344         else if(qstate->is_priming)
3345                 prime_supers(qstate, id, super);
3346         else    processTargetResponse(qstate, id, super);
3347 }
3348
3349 /**
3350  * Handle iterator state.
3351  * Handle events. This is the real processing loop for events, responsible
3352  * for moving events through the various states. If a processing method
3353  * returns true, then it will be advanced to the next state. If false, then
3354  * processing will stop.
3355  *
3356  * @param qstate: query state.
3357  * @param ie: iterator shared global environment.
3358  * @param iq: iterator query state.
3359  * @param id: module id.
3360  */
3361 static void
3362 iter_handle(struct module_qstate* qstate, struct iter_qstate* iq,
3363         struct iter_env* ie, int id)
3364 {
3365         int cont = 1;
3366         while(cont) {
3367                 verbose(VERB_ALGO, "iter_handle processing q with state %s",
3368                         iter_state_to_string(iq->state));
3369                 switch(iq->state) {
3370                         case INIT_REQUEST_STATE:
3371                                 cont = processInitRequest(qstate, iq, ie, id);
3372                                 break;
3373                         case INIT_REQUEST_2_STATE:
3374                                 cont = processInitRequest2(qstate, iq, id);
3375                                 break;
3376                         case INIT_REQUEST_3_STATE:
3377                                 cont = processInitRequest3(qstate, iq, id);
3378                                 break;
3379                         case QUERYTARGETS_STATE:
3380                                 cont = processQueryTargets(qstate, iq, ie, id);
3381                                 break;
3382                         case QUERY_RESP_STATE:
3383                                 cont = processQueryResponse(qstate, iq, id);
3384                                 break;
3385                         case PRIME_RESP_STATE:
3386                                 cont = processPrimeResponse(qstate, id);
3387                                 break;
3388                         case COLLECT_CLASS_STATE:
3389                                 cont = processCollectClass(qstate, id);
3390                                 break;
3391                         case DSNS_FIND_STATE:
3392                                 cont = processDSNSFind(qstate, iq, id);
3393                                 break;
3394                         case FINISHED_STATE:
3395                                 cont = processFinished(qstate, iq, id);
3396                                 break;
3397                         default:
3398                                 log_warn("iterator: invalid state: %d",
3399                                         iq->state);
3400                                 cont = 0;
3401                                 break;
3402                 }
3403         }
3404 }
3405
3406 /**
3407  * This is the primary entry point for processing request events. Note that
3408  * this method should only be used by external modules.
3409  * @param qstate: query state.
3410  * @param ie: iterator shared global environment.
3411  * @param iq: iterator query state.
3412  * @param id: module id.
3413  */
3414 static void
3415 process_request(struct module_qstate* qstate, struct iter_qstate* iq,
3416         struct iter_env* ie, int id)
3417 {
3418         /* external requests start in the INIT state, and finish using the
3419          * FINISHED state. */
3420         iq->state = INIT_REQUEST_STATE;
3421         iq->final_state = FINISHED_STATE;
3422         verbose(VERB_ALGO, "process_request: new external request event");
3423         iter_handle(qstate, iq, ie, id);
3424 }
3425
3426 /** process authoritative server reply */
3427 static void
3428 process_response(struct module_qstate* qstate, struct iter_qstate* iq,
3429         struct iter_env* ie, int id, struct outbound_entry* outbound,
3430         enum module_ev event)
3431 {
3432         struct msg_parse* prs;
3433         struct edns_data edns;
3434         sldns_buffer* pkt;
3435
3436         verbose(VERB_ALGO, "process_response: new external response event");
3437         iq->response = NULL;
3438         iq->state = QUERY_RESP_STATE;
3439         if(event == module_event_noreply || event == module_event_error) {
3440                 if(event == module_event_noreply && iq->sent_count >= 3 &&
3441                         qstate->env->cfg->use_caps_bits_for_id &&
3442                         !iq->caps_fallback) {
3443                         /* start fallback */
3444                         iq->caps_fallback = 1;
3445                         iq->caps_server = 0;
3446                         iq->caps_reply = NULL;
3447                         iq->caps_response = NULL;
3448                         iq->state = QUERYTARGETS_STATE;
3449                         iq->num_current_queries--;
3450                         /* need fresh attempts for the 0x20 fallback, if
3451                          * that was the cause for the failure */
3452                         iter_dec_attempts(iq->dp, 3);
3453                         verbose(VERB_DETAIL, "Capsforid: timeouts, starting fallback");
3454                         goto handle_it;
3455                 }
3456                 goto handle_it;
3457         }
3458         if( (event != module_event_reply && event != module_event_capsfail)
3459                 || !qstate->reply) {
3460                 log_err("Bad event combined with response");
3461                 outbound_list_remove(&iq->outlist, outbound);
3462                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3463                 return;
3464         }
3465
3466         /* parse message */
3467         prs = (struct msg_parse*)regional_alloc(qstate->env->scratch,
3468                 sizeof(struct msg_parse));
3469         if(!prs) {
3470                 log_err("out of memory on incoming message");
3471                 /* like packet got dropped */
3472                 goto handle_it;
3473         }
3474         memset(prs, 0, sizeof(*prs));
3475         memset(&edns, 0, sizeof(edns));
3476         pkt = qstate->reply->c->buffer;
3477         sldns_buffer_set_position(pkt, 0);
3478         if(parse_packet(pkt, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) {
3479                 verbose(VERB_ALGO, "parse error on reply packet");
3480                 goto handle_it;
3481         }
3482         /* edns is not examined, but removed from message to help cache */
3483         if(parse_extract_edns(prs, &edns, qstate->env->scratch) !=
3484                 LDNS_RCODE_NOERROR)
3485                 goto handle_it;
3486
3487         /* Copy the edns options we may got from the back end */
3488         if(edns.opt_list) {
3489                 qstate->edns_opts_back_in = edns_opt_copy_region(edns.opt_list,
3490                         qstate->region);
3491                 if(!qstate->edns_opts_back_in) {
3492                         log_err("out of memory on incoming message");
3493                         /* like packet got dropped */
3494                         goto handle_it;
3495                 }
3496                 if(!inplace_cb_edns_back_parsed_call(qstate->env, qstate)) {
3497                         log_err("unable to call edns_back_parsed callback");
3498                         goto handle_it;
3499                 }
3500         }
3501
3502         /* remove CD-bit, we asked for in case we handle validation ourself */
3503         prs->flags &= ~BIT_CD;
3504
3505         /* normalize and sanitize: easy to delete items from linked lists */
3506         if(!scrub_message(pkt, prs, &iq->qinfo_out, iq->dp->name,
3507                 qstate->env->scratch, qstate->env, ie)) {
3508                 /* if 0x20 enabled, start fallback, but we have no message */
3509                 if(event == module_event_capsfail && !iq->caps_fallback) {
3510                         iq->caps_fallback = 1;
3511                         iq->caps_server = 0;
3512                         iq->caps_reply = NULL;
3513                         iq->caps_response = NULL;
3514                         iq->state = QUERYTARGETS_STATE;
3515                         iq->num_current_queries--;
3516                         verbose(VERB_DETAIL, "Capsforid: scrub failed, starting fallback with no response");
3517                 }
3518                 goto handle_it;
3519         }
3520
3521         /* allocate response dns_msg in region */
3522         iq->response = dns_alloc_msg(pkt, prs, qstate->region);
3523         if(!iq->response)
3524                 goto handle_it;
3525         log_query_info(VERB_DETAIL, "response for", &qstate->qinfo);
3526         log_name_addr(VERB_DETAIL, "reply from", iq->dp->name,
3527                 &qstate->reply->addr, qstate->reply->addrlen);
3528         if(verbosity >= VERB_ALGO)
3529                 log_dns_msg("incoming scrubbed packet:", &iq->response->qinfo,
3530                         iq->response->rep);
3531
3532         if(event == module_event_capsfail || iq->caps_fallback) {
3533                 /* for fallback we care about main answer, not additionals */
3534                 /* removing that makes comparison more likely to succeed */
3535                 caps_strip_reply(iq->response->rep);
3536                 if(!iq->caps_fallback) {
3537                         /* start fallback */
3538                         iq->caps_fallback = 1;
3539                         iq->caps_server = 0;
3540                         iq->caps_reply = iq->response->rep;
3541                         iq->caps_response = iq->response;
3542                         iq->state = QUERYTARGETS_STATE;
3543                         iq->num_current_queries--;
3544                         verbose(VERB_DETAIL, "Capsforid: starting fallback");
3545                         goto handle_it;
3546                 } else {
3547                         /* check if reply is the same, otherwise, fail */
3548                         if(!iq->caps_reply) {
3549                                 iq->caps_reply = iq->response->rep;
3550                                 iq->caps_response = iq->response;
3551                                 iq->caps_server = -1; /*become zero at ++,
3552                                 so that we start the full set of trials */
3553                         } else if(caps_failed_rcode(iq->caps_reply) &&
3554                                 !caps_failed_rcode(iq->response->rep)) {
3555                                 /* prefer to upgrade to non-SERVFAIL */
3556                                 iq->caps_reply = iq->response->rep;
3557                                 iq->caps_response = iq->response;
3558                         } else if(!caps_failed_rcode(iq->caps_reply) &&
3559                                 caps_failed_rcode(iq->response->rep)) {
3560                                 /* if we have non-SERVFAIL as answer then
3561                                  * we can ignore SERVFAILs for the equality
3562                                  * comparison */
3563                                 /* no instructions here, skip other else */
3564                         } else if(caps_failed_rcode(iq->caps_reply) &&
3565                                 caps_failed_rcode(iq->response->rep)) {
3566                                 /* failure is same as other failure in fallbk*/
3567                                 /* no instructions here, skip other else */
3568                         } else if(!reply_equal(iq->response->rep, iq->caps_reply,
3569                                 qstate->env->scratch)) {
3570                                 verbose(VERB_DETAIL, "Capsforid fallback: "
3571                                         "getting different replies, failed");
3572                                 outbound_list_remove(&iq->outlist, outbound);
3573                                 (void)error_response(qstate, id,
3574                                         LDNS_RCODE_SERVFAIL);
3575                                 return;
3576                         }
3577                         /* continue the fallback procedure at next server */
3578                         iq->caps_server++;
3579                         iq->state = QUERYTARGETS_STATE;
3580                         iq->num_current_queries--;
3581                         verbose(VERB_DETAIL, "Capsforid: reply is equal. "
3582                                 "go to next fallback");
3583                         goto handle_it;
3584                 }
3585         }
3586         iq->caps_fallback = 0; /* if we were in fallback, 0x20 is OK now */
3587
3588 handle_it:
3589         outbound_list_remove(&iq->outlist, outbound);
3590         iter_handle(qstate, iq, ie, id);
3591 }
3592
3593 void
3594 iter_operate(struct module_qstate* qstate, enum module_ev event, int id,
3595         struct outbound_entry* outbound)
3596 {
3597         struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
3598         struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3599         verbose(VERB_QUERY, "iterator[module %d] operate: extstate:%s event:%s",
3600                 id, strextstate(qstate->ext_state[id]), strmodulevent(event));
3601         if(iq) log_query_info(VERB_QUERY, "iterator operate: query",
3602                 &qstate->qinfo);
3603         if(iq && qstate->qinfo.qname != iq->qchase.qname)
3604                 log_query_info(VERB_QUERY, "iterator operate: chased to",
3605                         &iq->qchase);
3606
3607         /* perform iterator state machine */
3608         if((event == module_event_new || event == module_event_pass) &&
3609                 iq == NULL) {
3610                 if(!iter_new(qstate, id)) {
3611                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3612                         return;
3613                 }
3614                 iq = (struct iter_qstate*)qstate->minfo[id];
3615                 process_request(qstate, iq, ie, id);
3616                 return;
3617         }
3618         if(iq && event == module_event_pass) {
3619                 iter_handle(qstate, iq, ie, id);
3620                 return;
3621         }
3622         if(iq && outbound) {
3623                 process_response(qstate, iq, ie, id, outbound, event);
3624                 return;
3625         }
3626         if(event == module_event_error) {
3627                 verbose(VERB_ALGO, "got called with event error, giving up");
3628                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3629                 return;
3630         }
3631
3632         log_err("bad event for iterator");
3633         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3634 }
3635
3636 void
3637 iter_clear(struct module_qstate* qstate, int id)
3638 {
3639         struct iter_qstate* iq;
3640         if(!qstate)
3641                 return;
3642         iq = (struct iter_qstate*)qstate->minfo[id];
3643         if(iq) {
3644                 outbound_list_clear(&iq->outlist);
3645                 if(iq->target_count && --iq->target_count[0] == 0)
3646                         free(iq->target_count);
3647                 iq->num_current_queries = 0;
3648         }
3649         qstate->minfo[id] = NULL;
3650 }
3651
3652 size_t
3653 iter_get_mem(struct module_env* env, int id)
3654 {
3655         struct iter_env* ie = (struct iter_env*)env->modinfo[id];
3656         if(!ie)
3657                 return 0;
3658         return sizeof(*ie) + sizeof(int)*((size_t)ie->max_dependency_depth+1)
3659                 + donotq_get_mem(ie->donotq) + priv_get_mem(ie->priv);
3660 }
3661
3662 /**
3663  * The iterator function block
3664  */
3665 static struct module_func_block iter_block = {
3666         "iterator",
3667         &iter_init, &iter_deinit, &iter_operate, &iter_inform_super,
3668         &iter_clear, &iter_get_mem
3669 };
3670
3671 struct module_func_block*
3672 iter_get_funcblock(void)
3673 {
3674         return &iter_block;
3675 }
3676
3677 const char*
3678 iter_state_to_string(enum iter_state state)
3679 {
3680         switch (state)
3681         {
3682         case INIT_REQUEST_STATE :
3683                 return "INIT REQUEST STATE";
3684         case INIT_REQUEST_2_STATE :
3685                 return "INIT REQUEST STATE (stage 2)";
3686         case INIT_REQUEST_3_STATE:
3687                 return "INIT REQUEST STATE (stage 3)";
3688         case QUERYTARGETS_STATE :
3689                 return "QUERY TARGETS STATE";
3690         case PRIME_RESP_STATE :
3691                 return "PRIME RESPONSE STATE";
3692         case COLLECT_CLASS_STATE :
3693                 return "COLLECT CLASS STATE";
3694         case DSNS_FIND_STATE :
3695                 return "DSNS FIND STATE";
3696         case QUERY_RESP_STATE :
3697                 return "QUERY RESPONSE STATE";
3698         case FINISHED_STATE :
3699                 return "FINISHED RESPONSE STATE";
3700         default :
3701                 return "UNKNOWN ITER STATE";
3702         }
3703 }
3704
3705 int
3706 iter_state_is_responsestate(enum iter_state s)
3707 {
3708         switch(s) {
3709                 case INIT_REQUEST_STATE :
3710                 case INIT_REQUEST_2_STATE :
3711                 case INIT_REQUEST_3_STATE :
3712                 case QUERYTARGETS_STATE :
3713                 case COLLECT_CLASS_STATE :
3714                         return 0;
3715                 default:
3716                         break;
3717         }
3718         return 1;
3719 }