contrib/unbound/iterator/iterator.c

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