1 /* 2 * iterator/iterator.c - iterative resolver DNS query response module 3 * 4 * Copyright (c) 2007, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * 15 * Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 19 * Neither the name of the NLNET LABS nor the names of its contributors may 20 * be used to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /** 37 * \file 38 * 39 * This file contains a module that performs recursive iterative DNS query 40 * processing. 41 */ 42 43 #include "config.h" 44 #include "iterator/iterator.h" 45 #include "iterator/iter_utils.h" 46 #include "iterator/iter_hints.h" 47 #include "iterator/iter_fwd.h" 48 #include "iterator/iter_donotq.h" 49 #include "iterator/iter_delegpt.h" 50 #include "iterator/iter_resptype.h" 51 #include "iterator/iter_scrub.h" 52 #include "iterator/iter_priv.h" 53 #include "validator/val_neg.h" 54 #include "services/cache/dns.h" 55 #include "services/cache/infra.h" 56 #include "services/authzone.h" 57 #include "util/module.h" 58 #include "util/netevent.h" 59 #include "util/net_help.h" 60 #include "util/regional.h" 61 #include "util/data/dname.h" 62 #include "util/data/msgencode.h" 63 #include "util/fptr_wlist.h" 64 #include "util/config_file.h" 65 #include "util/random.h" 66 #include "sldns/rrdef.h" 67 #include "sldns/wire2str.h" 68 #include "sldns/str2wire.h" 69 #include "sldns/parseutil.h" 70 #include "sldns/sbuffer.h" 71 72 /* in msec */ 73 int UNKNOWN_SERVER_NICENESS = 376; 74 /* in msec */ 75 int USEFUL_SERVER_TOP_TIMEOUT = 120000; 76 /* Equals USEFUL_SERVER_TOP_TIMEOUT*4 */ 77 int BLACKLIST_PENALTY = (120000*4); 78 79 static void target_count_increase_nx(struct iter_qstate* iq, int num); 80 81 int 82 iter_init(struct module_env* env, int id) 83 { 84 struct iter_env* iter_env = (struct iter_env*)calloc(1, 85 sizeof(struct iter_env)); 86 if(!iter_env) { 87 log_err("malloc failure"); 88 return 0; 89 } 90 env->modinfo[id] = (void*)iter_env; 91 92 lock_basic_init(&iter_env->queries_ratelimit_lock); 93 lock_protect(&iter_env->queries_ratelimit_lock, 94 &iter_env->num_queries_ratelimited, 95 sizeof(iter_env->num_queries_ratelimited)); 96 97 if(!iter_apply_cfg(iter_env, env->cfg)) { 98 log_err("iterator: could not apply configuration settings."); 99 return 0; 100 } 101 102 return 1; 103 } 104 105 /** delete caps_whitelist element */ 106 static void 107 caps_free(struct rbnode_type* n, void* ATTR_UNUSED(d)) 108 { 109 if(n) { 110 free(((struct name_tree_node*)n)->name); 111 free(n); 112 } 113 } 114 115 void 116 iter_deinit(struct module_env* env, int id) 117 { 118 struct iter_env* iter_env; 119 if(!env || !env->modinfo[id]) 120 return; 121 iter_env = (struct iter_env*)env->modinfo[id]; 122 lock_basic_destroy(&iter_env->queries_ratelimit_lock); 123 free(iter_env->target_fetch_policy); 124 priv_delete(iter_env->priv); 125 donotq_delete(iter_env->donotq); 126 if(iter_env->caps_white) { 127 traverse_postorder(iter_env->caps_white, caps_free, NULL); 128 free(iter_env->caps_white); 129 } 130 free(iter_env); 131 env->modinfo[id] = NULL; 132 } 133 134 /** new query for iterator */ 135 static int 136 iter_new(struct module_qstate* qstate, int id) 137 { 138 struct iter_qstate* iq = (struct iter_qstate*)regional_alloc( 139 qstate->region, sizeof(struct iter_qstate)); 140 qstate->minfo[id] = iq; 141 if(!iq) 142 return 0; 143 memset(iq, 0, sizeof(*iq)); 144 iq->state = INIT_REQUEST_STATE; 145 iq->final_state = FINISHED_STATE; 146 iq->an_prepend_list = NULL; 147 iq->an_prepend_last = NULL; 148 iq->ns_prepend_list = NULL; 149 iq->ns_prepend_last = NULL; 150 iq->dp = NULL; 151 iq->depth = 0; 152 iq->num_target_queries = 0; 153 iq->num_current_queries = 0; 154 iq->query_restart_count = 0; 155 iq->referral_count = 0; 156 iq->sent_count = 0; 157 iq->ratelimit_ok = 0; 158 iq->target_count = NULL; 159 iq->dp_target_count = 0; 160 iq->wait_priming_stub = 0; 161 iq->refetch_glue = 0; 162 iq->dnssec_expected = 0; 163 iq->dnssec_lame_query = 0; 164 iq->chase_flags = qstate->query_flags; 165 /* Start with the (current) qname. */ 166 iq->qchase = qstate->qinfo; 167 outbound_list_init(&iq->outlist); 168 iq->minimise_count = 0; 169 iq->timeout_count = 0; 170 if (qstate->env->cfg->qname_minimisation) 171 iq->minimisation_state = INIT_MINIMISE_STATE; 172 else 173 iq->minimisation_state = DONOT_MINIMISE_STATE; 174 175 memset(&iq->qinfo_out, 0, sizeof(struct query_info)); 176 return 1; 177 } 178 179 /** 180 * Transition to the next state. This can be used to advance a currently 181 * processing event. It cannot be used to reactivate a forEvent. 182 * 183 * @param iq: iterator query state 184 * @param nextstate The state to transition to. 185 * @return true. This is so this can be called as the return value for the 186 * actual process*State() methods. (Transitioning to the next state 187 * implies further processing). 188 */ 189 static int 190 next_state(struct iter_qstate* iq, enum iter_state nextstate) 191 { 192 /* If transitioning to a "response" state, make sure that there is a 193 * response */ 194 if(iter_state_is_responsestate(nextstate)) { 195 if(iq->response == NULL) { 196 log_err("transitioning to response state sans " 197 "response."); 198 } 199 } 200 iq->state = nextstate; 201 return 1; 202 } 203 204 /** 205 * Transition an event to its final state. Final states always either return 206 * a result up the module chain, or reactivate a dependent event. Which 207 * final state to transition to is set in the module state for the event when 208 * it was created, and depends on the original purpose of the event. 209 * 210 * The response is stored in the qstate->buf buffer. 211 * 212 * @param iq: iterator query state 213 * @return false. This is so this method can be used as the return value for 214 * the processState methods. (Transitioning to the final state 215 */ 216 static int 217 final_state(struct iter_qstate* iq) 218 { 219 return next_state(iq, iq->final_state); 220 } 221 222 /** 223 * Callback routine to handle errors in parent query states 224 * @param qstate: query state that failed. 225 * @param id: module id. 226 * @param super: super state. 227 */ 228 static void 229 error_supers(struct module_qstate* qstate, int id, struct module_qstate* super) 230 { 231 struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id]; 232 struct iter_qstate* super_iq = (struct iter_qstate*)super->minfo[id]; 233 234 if(qstate->qinfo.qtype == LDNS_RR_TYPE_A || 235 qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA) { 236 /* mark address as failed. */ 237 struct delegpt_ns* dpns = NULL; 238 super_iq->num_target_queries--; 239 if(super_iq->dp) 240 dpns = delegpt_find_ns(super_iq->dp, 241 qstate->qinfo.qname, qstate->qinfo.qname_len); 242 if(!dpns) { 243 /* not interested */ 244 /* this can happen, for eg. qname minimisation asked 245 * for an NXDOMAIN to be validated, and used qtype 246 * A for that, and the error of that, the name, is 247 * not listed in super_iq->dp */ 248 verbose(VERB_ALGO, "subq error, but not interested"); 249 log_query_info(VERB_ALGO, "superq", &super->qinfo); 250 return; 251 } else { 252 /* see if the failure did get (parent-lame) info */ 253 if(!cache_fill_missing(super->env, super_iq->qchase.qclass, 254 super->region, super_iq->dp)) 255 log_err("out of memory adding missing"); 256 } 257 delegpt_mark_neg(dpns, qstate->qinfo.qtype); 258 if((dpns->got4 == 2 || (!ie->supports_ipv4 && !ie->use_nat64)) && 259 (dpns->got6 == 2 || !ie->supports_ipv6)) { 260 dpns->resolved = 1; /* mark as failed */ 261 target_count_increase_nx(super_iq, 1); 262 } 263 } 264 if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS) { 265 /* prime failed to get delegation */ 266 super_iq->dp = NULL; 267 } 268 /* evaluate targets again */ 269 super_iq->state = QUERYTARGETS_STATE; 270 /* super becomes runnable, and will process this change */ 271 } 272 273 /** 274 * Return an error to the client 275 * @param qstate: our query state 276 * @param id: module id 277 * @param rcode: error code (DNS errcode). 278 * @return: 0 for use by caller, to make notation easy, like: 279 * return error_response(..). 280 */ 281 static int 282 error_response(struct module_qstate* qstate, int id, int rcode) 283 { 284 verbose(VERB_QUERY, "return error response %s", 285 sldns_lookup_by_id(sldns_rcodes, rcode)? 286 sldns_lookup_by_id(sldns_rcodes, rcode)->name:"??"); 287 qstate->return_rcode = rcode; 288 qstate->return_msg = NULL; 289 qstate->ext_state[id] = module_finished; 290 return 0; 291 } 292 293 /** 294 * Return an error to the client and cache the error code in the 295 * message cache (so per qname, qtype, qclass). 296 * @param qstate: our query state 297 * @param id: module id 298 * @param rcode: error code (DNS errcode). 299 * @return: 0 for use by caller, to make notation easy, like: 300 * return error_response(..). 301 */ 302 static int 303 error_response_cache(struct module_qstate* qstate, int id, int rcode) 304 { 305 struct reply_info err; 306 struct msgreply_entry* msg; 307 if(qstate->no_cache_store) { 308 return error_response(qstate, id, rcode); 309 } 310 if(qstate->prefetch_leeway > NORR_TTL) { 311 verbose(VERB_ALGO, "error response for prefetch in cache"); 312 /* attempt to adjust the cache entry prefetch */ 313 if(dns_cache_prefetch_adjust(qstate->env, &qstate->qinfo, 314 NORR_TTL, qstate->query_flags)) 315 return error_response(qstate, id, rcode); 316 /* if that fails (not in cache), fall through to store err */ 317 } 318 if((msg=msg_cache_lookup(qstate->env, 319 qstate->qinfo.qname, qstate->qinfo.qname_len, 320 qstate->qinfo.qtype, qstate->qinfo.qclass, 321 qstate->query_flags, 0, 322 qstate->env->cfg->serve_expired_ttl_reset)) != NULL) { 323 struct reply_info* rep = (struct reply_info*)msg->entry.data; 324 if(qstate->env->cfg->serve_expired && 325 qstate->env->cfg->serve_expired_ttl_reset && rep && 326 *qstate->env->now + qstate->env->cfg->serve_expired_ttl 327 > rep->serve_expired_ttl) { 328 verbose(VERB_ALGO, "reset serve-expired-ttl for " 329 "response in cache"); 330 rep->serve_expired_ttl = *qstate->env->now + 331 qstate->env->cfg->serve_expired_ttl; 332 } 333 if(rep && (FLAGS_GET_RCODE(rep->flags) == 334 LDNS_RCODE_NOERROR || 335 FLAGS_GET_RCODE(rep->flags) == 336 LDNS_RCODE_NXDOMAIN || 337 FLAGS_GET_RCODE(rep->flags) == 338 LDNS_RCODE_YXDOMAIN) && 339 (qstate->env->cfg->serve_expired || 340 *qstate->env->now <= rep->ttl)) { 341 /* we have a good entry, don't overwrite */ 342 lock_rw_unlock(&msg->entry.lock); 343 return error_response(qstate, id, rcode); 344 } 345 lock_rw_unlock(&msg->entry.lock); 346 /* nothing interesting is cached (already error response or 347 * expired good record when we don't serve expired), so this 348 * servfail cache entry is useful (stops waste of time on this 349 * servfail NORR_TTL) */ 350 } 351 /* store in cache */ 352 memset(&err, 0, sizeof(err)); 353 err.flags = (uint16_t)(BIT_QR | BIT_RA); 354 FLAGS_SET_RCODE(err.flags, rcode); 355 err.qdcount = 1; 356 err.ttl = NORR_TTL; 357 err.prefetch_ttl = PREFETCH_TTL_CALC(err.ttl); 358 err.serve_expired_ttl = NORR_TTL; 359 /* do not waste time trying to validate this servfail */ 360 err.security = sec_status_indeterminate; 361 verbose(VERB_ALGO, "store error response in message cache"); 362 iter_dns_store(qstate->env, &qstate->qinfo, &err, 0, 0, 0, NULL, 363 qstate->query_flags, qstate->qstarttime); 364 return error_response(qstate, id, rcode); 365 } 366 367 /** check if prepend item is duplicate item */ 368 static int 369 prepend_is_duplicate(struct ub_packed_rrset_key** sets, size_t to, 370 struct ub_packed_rrset_key* dup) 371 { 372 size_t i; 373 for(i=0; i<to; i++) { 374 if(sets[i]->rk.type == dup->rk.type && 375 sets[i]->rk.rrset_class == dup->rk.rrset_class && 376 sets[i]->rk.dname_len == dup->rk.dname_len && 377 query_dname_compare(sets[i]->rk.dname, dup->rk.dname) 378 == 0) 379 return 1; 380 } 381 return 0; 382 } 383 384 /** prepend the prepend list in the answer and authority section of dns_msg */ 385 static int 386 iter_prepend(struct iter_qstate* iq, struct dns_msg* msg, 387 struct regional* region) 388 { 389 struct iter_prep_list* p; 390 struct ub_packed_rrset_key** sets; 391 size_t num_an = 0, num_ns = 0;; 392 for(p = iq->an_prepend_list; p; p = p->next) 393 num_an++; 394 for(p = iq->ns_prepend_list; p; p = p->next) 395 num_ns++; 396 if(num_an + num_ns == 0) 397 return 1; 398 verbose(VERB_ALGO, "prepending %d rrsets", (int)num_an + (int)num_ns); 399 if(num_an > RR_COUNT_MAX || num_ns > RR_COUNT_MAX || 400 msg->rep->rrset_count > RR_COUNT_MAX) return 0; /* overflow */ 401 sets = regional_alloc(region, (num_an+num_ns+msg->rep->rrset_count) * 402 sizeof(struct ub_packed_rrset_key*)); 403 if(!sets) 404 return 0; 405 /* ANSWER section */ 406 num_an = 0; 407 for(p = iq->an_prepend_list; p; p = p->next) { 408 sets[num_an++] = p->rrset; 409 if(ub_packed_rrset_ttl(p->rrset) < msg->rep->ttl) 410 msg->rep->ttl = ub_packed_rrset_ttl(p->rrset); 411 } 412 memcpy(sets+num_an, msg->rep->rrsets, msg->rep->an_numrrsets * 413 sizeof(struct ub_packed_rrset_key*)); 414 /* AUTH section */ 415 num_ns = 0; 416 for(p = iq->ns_prepend_list; p; p = p->next) { 417 if(prepend_is_duplicate(sets+msg->rep->an_numrrsets+num_an, 418 num_ns, p->rrset) || prepend_is_duplicate( 419 msg->rep->rrsets+msg->rep->an_numrrsets, 420 msg->rep->ns_numrrsets, p->rrset)) 421 continue; 422 sets[msg->rep->an_numrrsets + num_an + num_ns++] = p->rrset; 423 if(ub_packed_rrset_ttl(p->rrset) < msg->rep->ttl) 424 msg->rep->ttl = ub_packed_rrset_ttl(p->rrset); 425 } 426 memcpy(sets + num_an + msg->rep->an_numrrsets + num_ns, 427 msg->rep->rrsets + msg->rep->an_numrrsets, 428 (msg->rep->ns_numrrsets + msg->rep->ar_numrrsets) * 429 sizeof(struct ub_packed_rrset_key*)); 430 431 /* NXDOMAIN rcode can stay if we prepended DNAME/CNAMEs, because 432 * this is what recursors should give. */ 433 msg->rep->rrset_count += num_an + num_ns; 434 msg->rep->an_numrrsets += num_an; 435 msg->rep->ns_numrrsets += num_ns; 436 msg->rep->rrsets = sets; 437 return 1; 438 } 439 440 /** 441 * Find rrset in ANSWER prepend list. 442 * to avoid duplicate DNAMEs when a DNAME is traversed twice. 443 * @param iq: iterator query state. 444 * @param rrset: rrset to add. 445 * @return false if not found 446 */ 447 static int 448 iter_find_rrset_in_prepend_answer(struct iter_qstate* iq, 449 struct ub_packed_rrset_key* rrset) 450 { 451 struct iter_prep_list* p = iq->an_prepend_list; 452 while(p) { 453 if(ub_rrset_compare(p->rrset, rrset) == 0 && 454 rrsetdata_equal((struct packed_rrset_data*)p->rrset 455 ->entry.data, (struct packed_rrset_data*)rrset 456 ->entry.data)) 457 return 1; 458 p = p->next; 459 } 460 return 0; 461 } 462 463 /** 464 * Add rrset to ANSWER prepend list 465 * @param qstate: query state. 466 * @param iq: iterator query state. 467 * @param rrset: rrset to add. 468 * @return false on failure (malloc). 469 */ 470 static int 471 iter_add_prepend_answer(struct module_qstate* qstate, struct iter_qstate* iq, 472 struct ub_packed_rrset_key* rrset) 473 { 474 struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc( 475 qstate->region, sizeof(struct iter_prep_list)); 476 if(!p) 477 return 0; 478 p->rrset = rrset; 479 p->next = NULL; 480 /* add at end */ 481 if(iq->an_prepend_last) 482 iq->an_prepend_last->next = p; 483 else iq->an_prepend_list = p; 484 iq->an_prepend_last = p; 485 return 1; 486 } 487 488 /** 489 * Add rrset to AUTHORITY prepend list 490 * @param qstate: query state. 491 * @param iq: iterator query state. 492 * @param rrset: rrset to add. 493 * @return false on failure (malloc). 494 */ 495 static int 496 iter_add_prepend_auth(struct module_qstate* qstate, struct iter_qstate* iq, 497 struct ub_packed_rrset_key* rrset) 498 { 499 struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc( 500 qstate->region, sizeof(struct iter_prep_list)); 501 if(!p) 502 return 0; 503 p->rrset = rrset; 504 p->next = NULL; 505 /* add at end */ 506 if(iq->ns_prepend_last) 507 iq->ns_prepend_last->next = p; 508 else iq->ns_prepend_list = p; 509 iq->ns_prepend_last = p; 510 return 1; 511 } 512 513 /** 514 * Given a CNAME response (defined as a response containing a CNAME or DNAME 515 * that does not answer the request), process the response, modifying the 516 * state as necessary. This follows the CNAME/DNAME chain and returns the 517 * final query name. 518 * 519 * sets the new query name, after following the CNAME/DNAME chain. 520 * @param qstate: query state. 521 * @param iq: iterator query state. 522 * @param msg: the response. 523 * @param mname: returned target new query name. 524 * @param mname_len: length of mname. 525 * @return false on (malloc) error. 526 */ 527 static int 528 handle_cname_response(struct module_qstate* qstate, struct iter_qstate* iq, 529 struct dns_msg* msg, uint8_t** mname, size_t* mname_len) 530 { 531 size_t i; 532 /* Start with the (current) qname. */ 533 *mname = iq->qchase.qname; 534 *mname_len = iq->qchase.qname_len; 535 536 /* Iterate over the ANSWER rrsets in order, looking for CNAMEs and 537 * DNAMES. */ 538 for(i=0; i<msg->rep->an_numrrsets; i++) { 539 struct ub_packed_rrset_key* r = msg->rep->rrsets[i]; 540 /* If there is a (relevant) DNAME, add it to the list. 541 * We always expect there to be CNAME that was generated 542 * by this DNAME following, so we don't process the DNAME 543 * directly. */ 544 if(ntohs(r->rk.type) == LDNS_RR_TYPE_DNAME && 545 dname_strict_subdomain_c(*mname, r->rk.dname) && 546 !iter_find_rrset_in_prepend_answer(iq, r)) { 547 if(!iter_add_prepend_answer(qstate, iq, r)) 548 return 0; 549 continue; 550 } 551 552 if(ntohs(r->rk.type) == LDNS_RR_TYPE_CNAME && 553 query_dname_compare(*mname, r->rk.dname) == 0 && 554 !iter_find_rrset_in_prepend_answer(iq, r)) { 555 /* Add this relevant CNAME rrset to the prepend list.*/ 556 if(!iter_add_prepend_answer(qstate, iq, r)) 557 return 0; 558 get_cname_target(r, mname, mname_len); 559 } 560 561 /* Other rrsets in the section are ignored. */ 562 } 563 /* add authority rrsets to authority prepend, for wildcarded CNAMEs */ 564 for(i=msg->rep->an_numrrsets; i<msg->rep->an_numrrsets + 565 msg->rep->ns_numrrsets; i++) { 566 struct ub_packed_rrset_key* r = msg->rep->rrsets[i]; 567 /* only add NSEC/NSEC3, as they may be needed for validation */ 568 if(ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC || 569 ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC3) { 570 if(!iter_add_prepend_auth(qstate, iq, r)) 571 return 0; 572 } 573 } 574 return 1; 575 } 576 577 /** fill fail address for later recovery */ 578 static void 579 fill_fail_addr(struct iter_qstate* iq, struct sockaddr_storage* addr, 580 socklen_t addrlen) 581 { 582 if(addrlen == 0) { 583 iq->fail_addr_type = 0; 584 return; 585 } 586 if(((struct sockaddr_in*)addr)->sin_family == AF_INET) { 587 iq->fail_addr_type = 4; 588 memcpy(&iq->fail_addr.in, 589 &((struct sockaddr_in*)addr)->sin_addr, 590 sizeof(iq->fail_addr.in)); 591 } 592 #ifdef AF_INET6 593 else if(((struct sockaddr_in*)addr)->sin_family == AF_INET6) { 594 iq->fail_addr_type = 6; 595 memcpy(&iq->fail_addr.in6, 596 &((struct sockaddr_in6*)addr)->sin6_addr, 597 sizeof(iq->fail_addr.in6)); 598 } 599 #endif 600 else { 601 iq->fail_addr_type = 0; 602 } 603 } 604 605 /** print fail addr to string */ 606 static void 607 print_fail_addr(struct iter_qstate* iq, char* buf, size_t len) 608 { 609 if(iq->fail_addr_type == 4) { 610 if(inet_ntop(AF_INET, &iq->fail_addr.in, buf, 611 (socklen_t)len) == 0) 612 (void)strlcpy(buf, "(inet_ntop error)", len); 613 } 614 #ifdef AF_INET6 615 else if(iq->fail_addr_type == 6) { 616 if(inet_ntop(AF_INET6, &iq->fail_addr.in6, buf, 617 (socklen_t)len) == 0) 618 (void)strlcpy(buf, "(inet_ntop error)", len); 619 } 620 #endif 621 else 622 (void)strlcpy(buf, "", len); 623 } 624 625 /** add response specific error information for log servfail */ 626 static void 627 errinf_reply(struct module_qstate* qstate, struct iter_qstate* iq) 628 { 629 if(qstate->env->cfg->val_log_level < 2 && !qstate->env->cfg->log_servfail) 630 return; 631 if((qstate->reply && qstate->reply->remote_addrlen != 0) || 632 (iq->fail_addr_type != 0)) { 633 char from[256], frm[512]; 634 if(qstate->reply && qstate->reply->remote_addrlen != 0) 635 addr_to_str(&qstate->reply->remote_addr, 636 qstate->reply->remote_addrlen, from, 637 sizeof(from)); 638 else 639 print_fail_addr(iq, from, sizeof(from)); 640 snprintf(frm, sizeof(frm), "from %s", from); 641 errinf(qstate, frm); 642 } 643 if(iq->scrub_failures || iq->parse_failures) { 644 if(iq->scrub_failures) 645 errinf(qstate, "upstream response failed scrub"); 646 if(iq->parse_failures) 647 errinf(qstate, "could not parse upstream response"); 648 } else if(iq->response == NULL && iq->timeout_count != 0) { 649 errinf(qstate, "upstream server timeout"); 650 } else if(iq->response == NULL) { 651 errinf(qstate, "no server to query"); 652 if(iq->dp) { 653 if(iq->dp->target_list == NULL) 654 errinf(qstate, "no addresses for nameservers"); 655 else errinf(qstate, "nameserver addresses not usable"); 656 if(iq->dp->nslist == NULL) 657 errinf(qstate, "have no nameserver names"); 658 if(iq->dp->bogus) 659 errinf(qstate, "NS record was dnssec bogus"); 660 } 661 } 662 if(iq->response && iq->response->rep) { 663 if(FLAGS_GET_RCODE(iq->response->rep->flags) != 0) { 664 char rcode[256], rc[32]; 665 (void)sldns_wire2str_rcode_buf( 666 FLAGS_GET_RCODE(iq->response->rep->flags), 667 rc, sizeof(rc)); 668 snprintf(rcode, sizeof(rcode), "got %s", rc); 669 errinf(qstate, rcode); 670 } else { 671 /* rcode NOERROR */ 672 if(iq->response->rep->an_numrrsets == 0) { 673 errinf(qstate, "nodata answer"); 674 } 675 } 676 } 677 } 678 679 /** see if last resort is possible - does config allow queries to parent */ 680 static int 681 can_have_last_resort(struct module_env* env, uint8_t* nm, size_t nmlen, 682 uint16_t qclass, struct delegpt** retdp) 683 { 684 struct delegpt* fwddp; 685 struct iter_hints_stub* stub; 686 int labs = dname_count_labels(nm); 687 /* do not process a last resort (the parent side) if a stub 688 * or forward is configured, because we do not want to go 'above' 689 * the configured servers */ 690 if(!dname_is_root(nm) && (stub = (struct iter_hints_stub*) 691 name_tree_find(&env->hints->tree, nm, nmlen, labs, qclass)) && 692 /* has_parent side is turned off for stub_first, where we 693 * are allowed to go to the parent */ 694 stub->dp->has_parent_side_NS) { 695 if(retdp) *retdp = stub->dp; 696 return 0; 697 } 698 if((fwddp = forwards_find(env->fwds, nm, qclass)) && 699 /* has_parent_side is turned off for forward_first, where 700 * we are allowed to go to the parent */ 701 fwddp->has_parent_side_NS) { 702 if(retdp) *retdp = fwddp; 703 return 0; 704 } 705 return 1; 706 } 707 708 /** see if target name is caps-for-id whitelisted */ 709 static int 710 is_caps_whitelisted(struct iter_env* ie, struct iter_qstate* iq) 711 { 712 if(!ie->caps_white) return 0; /* no whitelist, or no capsforid */ 713 return name_tree_lookup(ie->caps_white, iq->qchase.qname, 714 iq->qchase.qname_len, dname_count_labels(iq->qchase.qname), 715 iq->qchase.qclass) != NULL; 716 } 717 718 /** 719 * Create target count structure for this query. This is always explicitly 720 * created for the parent query. 721 */ 722 static void 723 target_count_create(struct iter_qstate* iq) 724 { 725 if(!iq->target_count) { 726 iq->target_count = (int*)calloc(TARGET_COUNT_MAX, sizeof(int)); 727 /* if calloc fails we simply do not track this number */ 728 if(iq->target_count) { 729 iq->target_count[TARGET_COUNT_REF] = 1; 730 iq->nxns_dp = (uint8_t**)calloc(1, sizeof(uint8_t*)); 731 } 732 } 733 } 734 735 static void 736 target_count_increase(struct iter_qstate* iq, int num) 737 { 738 target_count_create(iq); 739 if(iq->target_count) 740 iq->target_count[TARGET_COUNT_QUERIES] += num; 741 iq->dp_target_count++; 742 } 743 744 static void 745 target_count_increase_nx(struct iter_qstate* iq, int num) 746 { 747 target_count_create(iq); 748 if(iq->target_count) 749 iq->target_count[TARGET_COUNT_NX] += num; 750 } 751 752 /** 753 * Generate a subrequest. 754 * Generate a local request event. Local events are tied to this module, and 755 * have a corresponding (first tier) event that is waiting for this event to 756 * resolve to continue. 757 * 758 * @param qname The query name for this request. 759 * @param qnamelen length of qname 760 * @param qtype The query type for this request. 761 * @param qclass The query class for this request. 762 * @param qstate The event that is generating this event. 763 * @param id: module id. 764 * @param iq: The iterator state that is generating this event. 765 * @param initial_state The initial response state (normally this 766 * is QUERY_RESP_STATE, unless it is known that the request won't 767 * need iterative processing 768 * @param finalstate The final state for the response to this request. 769 * @param subq_ret: if newly allocated, the subquerystate, or NULL if it does 770 * not need initialisation. 771 * @param v: if true, validation is done on the subquery. 772 * @param detached: true if this qstate should not attach to the subquery 773 * @return false on error (malloc). 774 */ 775 static int 776 generate_sub_request(uint8_t* qname, size_t qnamelen, uint16_t qtype, 777 uint16_t qclass, struct module_qstate* qstate, int id, 778 struct iter_qstate* iq, enum iter_state initial_state, 779 enum iter_state finalstate, struct module_qstate** subq_ret, int v, 780 int detached) 781 { 782 struct module_qstate* subq = NULL; 783 struct iter_qstate* subiq = NULL; 784 uint16_t qflags = 0; /* OPCODE QUERY, no flags */ 785 struct query_info qinf; 786 int prime = (finalstate == PRIME_RESP_STATE)?1:0; 787 int valrec = 0; 788 qinf.qname = qname; 789 qinf.qname_len = qnamelen; 790 qinf.qtype = qtype; 791 qinf.qclass = qclass; 792 qinf.local_alias = NULL; 793 794 /* RD should be set only when sending the query back through the INIT 795 * state. */ 796 if(initial_state == INIT_REQUEST_STATE) 797 qflags |= BIT_RD; 798 /* We set the CD flag so we can send this through the "head" of 799 * the resolution chain, which might have a validator. We are 800 * uninterested in validating things not on the direct resolution 801 * path. */ 802 if(!v) { 803 qflags |= BIT_CD; 804 valrec = 1; 805 } 806 807 if(detached) { 808 struct mesh_state* sub = NULL; 809 fptr_ok(fptr_whitelist_modenv_add_sub( 810 qstate->env->add_sub)); 811 if(!(*qstate->env->add_sub)(qstate, &qinf, 812 qflags, prime, valrec, &subq, &sub)){ 813 return 0; 814 } 815 } 816 else { 817 /* attach subquery, lookup existing or make a new one */ 818 fptr_ok(fptr_whitelist_modenv_attach_sub( 819 qstate->env->attach_sub)); 820 if(!(*qstate->env->attach_sub)(qstate, &qinf, qflags, prime, 821 valrec, &subq)) { 822 return 0; 823 } 824 } 825 *subq_ret = subq; 826 if(subq) { 827 /* initialise the new subquery */ 828 subq->curmod = id; 829 subq->ext_state[id] = module_state_initial; 830 subq->minfo[id] = regional_alloc(subq->region, 831 sizeof(struct iter_qstate)); 832 if(!subq->minfo[id]) { 833 log_err("init subq: out of memory"); 834 fptr_ok(fptr_whitelist_modenv_kill_sub( 835 qstate->env->kill_sub)); 836 (*qstate->env->kill_sub)(subq); 837 return 0; 838 } 839 subiq = (struct iter_qstate*)subq->minfo[id]; 840 memset(subiq, 0, sizeof(*subiq)); 841 subiq->num_target_queries = 0; 842 target_count_create(iq); 843 subiq->target_count = iq->target_count; 844 if(iq->target_count) { 845 iq->target_count[TARGET_COUNT_REF] ++; /* extra reference */ 846 subiq->nxns_dp = iq->nxns_dp; 847 } 848 subiq->dp_target_count = 0; 849 subiq->num_current_queries = 0; 850 subiq->depth = iq->depth+1; 851 outbound_list_init(&subiq->outlist); 852 subiq->state = initial_state; 853 subiq->final_state = finalstate; 854 subiq->qchase = subq->qinfo; 855 subiq->chase_flags = subq->query_flags; 856 subiq->refetch_glue = 0; 857 if(qstate->env->cfg->qname_minimisation) 858 subiq->minimisation_state = INIT_MINIMISE_STATE; 859 else 860 subiq->minimisation_state = DONOT_MINIMISE_STATE; 861 memset(&subiq->qinfo_out, 0, sizeof(struct query_info)); 862 } 863 return 1; 864 } 865 866 /** 867 * Generate and send a root priming request. 868 * @param qstate: the qtstate that triggered the need to prime. 869 * @param iq: iterator query state. 870 * @param id: module id. 871 * @param qclass: the class to prime. 872 * @return 0 on failure 873 */ 874 static int 875 prime_root(struct module_qstate* qstate, struct iter_qstate* iq, int id, 876 uint16_t qclass) 877 { 878 struct delegpt* dp; 879 struct module_qstate* subq; 880 verbose(VERB_DETAIL, "priming . %s NS", 881 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)? 882 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)->name:"??"); 883 dp = hints_lookup_root(qstate->env->hints, qclass); 884 if(!dp) { 885 verbose(VERB_ALGO, "Cannot prime due to lack of hints"); 886 return 0; 887 } 888 /* Priming requests start at the QUERYTARGETS state, skipping 889 * the normal INIT state logic (which would cause an infloop). */ 890 if(!generate_sub_request((uint8_t*)"\000", 1, LDNS_RR_TYPE_NS, 891 qclass, qstate, id, iq, QUERYTARGETS_STATE, PRIME_RESP_STATE, 892 &subq, 0, 0)) { 893 verbose(VERB_ALGO, "could not prime root"); 894 return 0; 895 } 896 if(subq) { 897 struct iter_qstate* subiq = 898 (struct iter_qstate*)subq->minfo[id]; 899 /* Set the initial delegation point to the hint. 900 * copy dp, it is now part of the root prime query. 901 * dp was part of in the fixed hints structure. */ 902 subiq->dp = delegpt_copy(dp, subq->region); 903 if(!subiq->dp) { 904 log_err("out of memory priming root, copydp"); 905 fptr_ok(fptr_whitelist_modenv_kill_sub( 906 qstate->env->kill_sub)); 907 (*qstate->env->kill_sub)(subq); 908 return 0; 909 } 910 /* there should not be any target queries. */ 911 subiq->num_target_queries = 0; 912 subiq->dnssec_expected = iter_indicates_dnssec( 913 qstate->env, subiq->dp, NULL, subq->qinfo.qclass); 914 } 915 916 /* this module stops, our submodule starts, and does the query. */ 917 qstate->ext_state[id] = module_wait_subquery; 918 return 1; 919 } 920 921 /** 922 * Generate and process a stub priming request. This method tests for the 923 * need to prime a stub zone, so it is safe to call for every request. 924 * 925 * @param qstate: the qtstate that triggered the need to prime. 926 * @param iq: iterator query state. 927 * @param id: module id. 928 * @param qname: request name. 929 * @param qclass: request class. 930 * @return true if a priming subrequest was made, false if not. The will only 931 * issue a priming request if it detects an unprimed stub. 932 * Uses value of 2 to signal during stub-prime in root-prime situation 933 * that a noprime-stub is available and resolution can continue. 934 */ 935 static int 936 prime_stub(struct module_qstate* qstate, struct iter_qstate* iq, int id, 937 uint8_t* qname, uint16_t qclass) 938 { 939 /* Lookup the stub hint. This will return null if the stub doesn't 940 * need to be re-primed. */ 941 struct iter_hints_stub* stub; 942 struct delegpt* stub_dp; 943 struct module_qstate* subq; 944 945 if(!qname) return 0; 946 stub = hints_lookup_stub(qstate->env->hints, qname, qclass, iq->dp); 947 /* The stub (if there is one) does not need priming. */ 948 if(!stub) 949 return 0; 950 stub_dp = stub->dp; 951 /* if we have an auth_zone dp, and stub is equal, don't prime stub 952 * yet, unless we want to fallback and avoid the auth_zone */ 953 if(!iq->auth_zone_avoid && iq->dp && iq->dp->auth_dp && 954 query_dname_compare(iq->dp->name, stub_dp->name) == 0) 955 return 0; 956 957 /* is it a noprime stub (always use) */ 958 if(stub->noprime) { 959 int r = 0; 960 if(iq->dp == NULL) r = 2; 961 /* copy the dp out of the fixed hints structure, so that 962 * it can be changed when servicing this query */ 963 iq->dp = delegpt_copy(stub_dp, qstate->region); 964 if(!iq->dp) { 965 log_err("out of memory priming stub"); 966 errinf(qstate, "malloc failure, priming stub"); 967 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); 968 return 1; /* return 1 to make module stop, with error */ 969 } 970 log_nametypeclass(VERB_DETAIL, "use stub", stub_dp->name, 971 LDNS_RR_TYPE_NS, qclass); 972 return r; 973 } 974 975 /* Otherwise, we need to (re)prime the stub. */ 976 log_nametypeclass(VERB_DETAIL, "priming stub", stub_dp->name, 977 LDNS_RR_TYPE_NS, qclass); 978 979 /* Stub priming events start at the QUERYTARGETS state to avoid the 980 * redundant INIT state processing. */ 981 if(!generate_sub_request(stub_dp->name, stub_dp->namelen, 982 LDNS_RR_TYPE_NS, qclass, qstate, id, iq, 983 QUERYTARGETS_STATE, PRIME_RESP_STATE, &subq, 0, 0)) { 984 verbose(VERB_ALGO, "could not prime stub"); 985 errinf(qstate, "could not generate lookup for stub prime"); 986 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); 987 return 1; /* return 1 to make module stop, with error */ 988 } 989 if(subq) { 990 struct iter_qstate* subiq = 991 (struct iter_qstate*)subq->minfo[id]; 992 993 /* Set the initial delegation point to the hint. */ 994 /* make copy to avoid use of stub dp by different qs/threads */ 995 subiq->dp = delegpt_copy(stub_dp, subq->region); 996 if(!subiq->dp) { 997 log_err("out of memory priming stub, copydp"); 998 fptr_ok(fptr_whitelist_modenv_kill_sub( 999 qstate->env->kill_sub)); 1000 (*qstate->env->kill_sub)(subq); 1001 errinf(qstate, "malloc failure, in stub prime"); 1002 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); 1003 return 1; /* return 1 to make module stop, with error */ 1004 } 1005 /* there should not be any target queries -- although there 1006 * wouldn't be anyway, since stub hints never have 1007 * missing targets. */ 1008 subiq->num_target_queries = 0; 1009 subiq->wait_priming_stub = 1; 1010 subiq->dnssec_expected = iter_indicates_dnssec( 1011 qstate->env, subiq->dp, NULL, subq->qinfo.qclass); 1012 } 1013 1014 /* this module stops, our submodule starts, and does the query. */ 1015 qstate->ext_state[id] = module_wait_subquery; 1016 return 1; 1017 } 1018 1019 /** 1020 * Generate a delegation point for an auth zone (unless cached dp is better) 1021 * false on alloc failure. 1022 */ 1023 static int 1024 auth_zone_delegpt(struct module_qstate* qstate, struct iter_qstate* iq, 1025 uint8_t* delname, size_t delnamelen) 1026 { 1027 struct auth_zone* z; 1028 if(iq->auth_zone_avoid) 1029 return 1; 1030 if(!delname) { 1031 delname = iq->qchase.qname; 1032 delnamelen = iq->qchase.qname_len; 1033 } 1034 lock_rw_rdlock(&qstate->env->auth_zones->lock); 1035 z = auth_zones_find_zone(qstate->env->auth_zones, delname, delnamelen, 1036 qstate->qinfo.qclass); 1037 if(!z) { 1038 lock_rw_unlock(&qstate->env->auth_zones->lock); 1039 return 1; 1040 } 1041 lock_rw_rdlock(&z->lock); 1042 lock_rw_unlock(&qstate->env->auth_zones->lock); 1043 if(z->for_upstream) { 1044 if(iq->dp && query_dname_compare(z->name, iq->dp->name) == 0 1045 && iq->dp->auth_dp && qstate->blacklist && 1046 z->fallback_enabled) { 1047 /* cache is blacklisted and fallback, and we 1048 * already have an auth_zone dp */ 1049 if(verbosity>=VERB_ALGO) { 1050 char buf[255+1]; 1051 dname_str(z->name, buf); 1052 verbose(VERB_ALGO, "auth_zone %s " 1053 "fallback because cache blacklisted", 1054 buf); 1055 } 1056 lock_rw_unlock(&z->lock); 1057 iq->dp = NULL; 1058 return 1; 1059 } 1060 if(iq->dp==NULL || dname_subdomain_c(z->name, iq->dp->name)) { 1061 struct delegpt* dp; 1062 if(qstate->blacklist && z->fallback_enabled) { 1063 /* cache is blacklisted because of a DNSSEC 1064 * validation failure, and the zone allows 1065 * fallback to the internet, query there. */ 1066 if(verbosity>=VERB_ALGO) { 1067 char buf[255+1]; 1068 dname_str(z->name, buf); 1069 verbose(VERB_ALGO, "auth_zone %s " 1070 "fallback because cache blacklisted", 1071 buf); 1072 } 1073 lock_rw_unlock(&z->lock); 1074 return 1; 1075 } 1076 dp = (struct delegpt*)regional_alloc_zero( 1077 qstate->region, sizeof(*dp)); 1078 if(!dp) { 1079 log_err("alloc failure"); 1080 if(z->fallback_enabled) { 1081 lock_rw_unlock(&z->lock); 1082 return 1; /* just fallback */ 1083 } 1084 lock_rw_unlock(&z->lock); 1085 errinf(qstate, "malloc failure"); 1086 return 0; 1087 } 1088 dp->name = regional_alloc_init(qstate->region, 1089 z->name, z->namelen); 1090 if(!dp->name) { 1091 log_err("alloc failure"); 1092 if(z->fallback_enabled) { 1093 lock_rw_unlock(&z->lock); 1094 return 1; /* just fallback */ 1095 } 1096 lock_rw_unlock(&z->lock); 1097 errinf(qstate, "malloc failure"); 1098 return 0; 1099 } 1100 dp->namelen = z->namelen; 1101 dp->namelabs = z->namelabs; 1102 dp->auth_dp = 1; 1103 iq->dp = dp; 1104 } 1105 } 1106 1107 lock_rw_unlock(&z->lock); 1108 return 1; 1109 } 1110 1111 /** 1112 * Generate A and AAAA checks for glue that is in-zone for the referral 1113 * we just got to obtain authoritative information on the addresses. 1114 * 1115 * @param qstate: the qtstate that triggered the need to prime. 1116 * @param iq: iterator query state. 1117 * @param id: module id. 1118 */ 1119 static void 1120 generate_a_aaaa_check(struct module_qstate* qstate, struct iter_qstate* iq, 1121 int id) 1122 { 1123 struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id]; 1124 struct module_qstate* subq; 1125 size_t i; 1126 struct reply_info* rep = iq->response->rep; 1127 struct ub_packed_rrset_key* s; 1128 log_assert(iq->dp); 1129 1130 if(iq->depth == ie->max_dependency_depth) 1131 return; 1132 /* walk through additional, and check if in-zone, 1133 * only relevant A, AAAA are left after scrub anyway */ 1134 for(i=rep->an_numrrsets+rep->ns_numrrsets; i<rep->rrset_count; i++) { 1135 s = rep->rrsets[i]; 1136 /* check *ALL* addresses that are transmitted in additional*/ 1137 /* is it an address ? */ 1138 if( !(ntohs(s->rk.type)==LDNS_RR_TYPE_A || 1139 ntohs(s->rk.type)==LDNS_RR_TYPE_AAAA)) { 1140 continue; 1141 } 1142 /* is this query the same as the A/AAAA check for it */ 1143 if(qstate->qinfo.qtype == ntohs(s->rk.type) && 1144 qstate->qinfo.qclass == ntohs(s->rk.rrset_class) && 1145 query_dname_compare(qstate->qinfo.qname, 1146 s->rk.dname)==0 && 1147 (qstate->query_flags&BIT_RD) && 1148 !(qstate->query_flags&BIT_CD)) 1149 continue; 1150 1151 /* generate subrequest for it */ 1152 log_nametypeclass(VERB_ALGO, "schedule addr fetch", 1153 s->rk.dname, ntohs(s->rk.type), 1154 ntohs(s->rk.rrset_class)); 1155 if(!generate_sub_request(s->rk.dname, s->rk.dname_len, 1156 ntohs(s->rk.type), ntohs(s->rk.rrset_class), 1157 qstate, id, iq, 1158 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1, 0)) { 1159 verbose(VERB_ALGO, "could not generate addr check"); 1160 return; 1161 } 1162 /* ignore subq - not need for more init */ 1163 } 1164 } 1165 1166 /** 1167 * Generate a NS check request to obtain authoritative information 1168 * on an NS rrset. 1169 * 1170 * @param qstate: the qstate that triggered the need to prime. 1171 * @param iq: iterator query state. 1172 * @param id: module id. 1173 */ 1174 static void 1175 generate_ns_check(struct module_qstate* qstate, struct iter_qstate* iq, int id) 1176 { 1177 struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id]; 1178 struct module_qstate* subq; 1179 log_assert(iq->dp); 1180 1181 if(iq->depth == ie->max_dependency_depth) 1182 return; 1183 if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen, 1184 iq->qchase.qclass, NULL)) 1185 return; 1186 /* is this query the same as the nscheck? */ 1187 if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS && 1188 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 && 1189 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){ 1190 /* spawn off A, AAAA queries for in-zone glue to check */ 1191 generate_a_aaaa_check(qstate, iq, id); 1192 return; 1193 } 1194 /* no need to get the NS record for DS, it is above the zonecut */ 1195 if(qstate->qinfo.qtype == LDNS_RR_TYPE_DS) 1196 return; 1197 1198 log_nametypeclass(VERB_ALGO, "schedule ns fetch", 1199 iq->dp->name, LDNS_RR_TYPE_NS, iq->qchase.qclass); 1200 if(!generate_sub_request(iq->dp->name, iq->dp->namelen, 1201 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq, 1202 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1, 0)) { 1203 verbose(VERB_ALGO, "could not generate ns check"); 1204 return; 1205 } 1206 if(subq) { 1207 struct iter_qstate* subiq = 1208 (struct iter_qstate*)subq->minfo[id]; 1209 1210 /* make copy to avoid use of stub dp by different qs/threads */ 1211 /* refetch glue to start higher up the tree */ 1212 subiq->refetch_glue = 1; 1213 subiq->dp = delegpt_copy(iq->dp, subq->region); 1214 if(!subiq->dp) { 1215 log_err("out of memory generating ns check, copydp"); 1216 fptr_ok(fptr_whitelist_modenv_kill_sub( 1217 qstate->env->kill_sub)); 1218 (*qstate->env->kill_sub)(subq); 1219 return; 1220 } 1221 } 1222 } 1223 1224 /** 1225 * Generate a DNSKEY prefetch query to get the DNSKEY for the DS record we 1226 * just got in a referral (where we have dnssec_expected, thus have trust 1227 * anchors above it). Note that right after calling this routine the 1228 * iterator detached subqueries (because of following the referral), and thus 1229 * the DNSKEY query becomes detached, its return stored in the cache for 1230 * later lookup by the validator. This cache lookup by the validator avoids 1231 * the roundtrip incurred by the DNSKEY query. The DNSKEY query is now 1232 * performed at about the same time the original query is sent to the domain, 1233 * thus the two answers are likely to be returned at about the same time, 1234 * saving a roundtrip from the validated lookup. 1235 * 1236 * @param qstate: the qtstate that triggered the need to prime. 1237 * @param iq: iterator query state. 1238 * @param id: module id. 1239 */ 1240 static void 1241 generate_dnskey_prefetch(struct module_qstate* qstate, 1242 struct iter_qstate* iq, int id) 1243 { 1244 struct module_qstate* subq; 1245 log_assert(iq->dp); 1246 1247 /* is this query the same as the prefetch? */ 1248 if(qstate->qinfo.qtype == LDNS_RR_TYPE_DNSKEY && 1249 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 && 1250 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){ 1251 return; 1252 } 1253 /* we do not generate this prefetch when the query list is full, 1254 * the query is fetched, if needed, when the validator wants it. 1255 * At that time the validator waits for it, after spawning it. 1256 * This means there is one state that uses cpu and a socket, the 1257 * spawned while this one waits, and not several at the same time, 1258 * if we had created the lookup here. And this helps to keep 1259 * the total load down, but the query still succeeds to resolve. */ 1260 if(mesh_jostle_exceeded(qstate->env->mesh)) 1261 return; 1262 1263 /* if the DNSKEY is in the cache this lookup will stop quickly */ 1264 log_nametypeclass(VERB_ALGO, "schedule dnskey prefetch", 1265 iq->dp->name, LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass); 1266 if(!generate_sub_request(iq->dp->name, iq->dp->namelen, 1267 LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass, qstate, id, iq, 1268 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0)) { 1269 /* we'll be slower, but it'll work */ 1270 verbose(VERB_ALGO, "could not generate dnskey prefetch"); 1271 return; 1272 } 1273 if(subq) { 1274 struct iter_qstate* subiq = 1275 (struct iter_qstate*)subq->minfo[id]; 1276 /* this qstate has the right delegation for the dnskey lookup*/ 1277 /* make copy to avoid use of stub dp by different qs/threads */ 1278 subiq->dp = delegpt_copy(iq->dp, subq->region); 1279 /* if !subiq->dp, it'll start from the cache, no problem */ 1280 } 1281 } 1282 1283 /** 1284 * See if the query needs forwarding. 1285 * 1286 * @param qstate: query state. 1287 * @param iq: iterator query state. 1288 * @return true if the request is forwarded, false if not. 1289 * If returns true but, iq->dp is NULL then a malloc failure occurred. 1290 */ 1291 static int 1292 forward_request(struct module_qstate* qstate, struct iter_qstate* iq) 1293 { 1294 struct delegpt* dp; 1295 uint8_t* delname = iq->qchase.qname; 1296 size_t delnamelen = iq->qchase.qname_len; 1297 if(iq->refetch_glue && iq->dp) { 1298 delname = iq->dp->name; 1299 delnamelen = iq->dp->namelen; 1300 } 1301 /* strip one label off of DS query to lookup higher for it */ 1302 if( (iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue) 1303 && !dname_is_root(iq->qchase.qname)) 1304 dname_remove_label(&delname, &delnamelen); 1305 dp = forwards_lookup(qstate->env->fwds, delname, iq->qchase.qclass); 1306 if(!dp) 1307 return 0; 1308 /* send recursion desired to forward addr */ 1309 iq->chase_flags |= BIT_RD; 1310 iq->dp = delegpt_copy(dp, qstate->region); 1311 /* iq->dp checked by caller */ 1312 verbose(VERB_ALGO, "forwarding request"); 1313 return 1; 1314 } 1315 1316 /** 1317 * Process the initial part of the request handling. This state roughly 1318 * corresponds to resolver algorithms steps 1 (find answer in cache) and 2 1319 * (find the best servers to ask). 1320 * 1321 * Note that all requests start here, and query restarts revisit this state. 1322 * 1323 * This state either generates: 1) a response, from cache or error, 2) a 1324 * priming event, or 3) forwards the request to the next state (init2, 1325 * generally). 1326 * 1327 * @param qstate: query state. 1328 * @param iq: iterator query state. 1329 * @param ie: iterator shared global environment. 1330 * @param id: module id. 1331 * @return true if the event needs more request processing immediately, 1332 * false if not. 1333 */ 1334 static int 1335 processInitRequest(struct module_qstate* qstate, struct iter_qstate* iq, 1336 struct iter_env* ie, int id) 1337 { 1338 uint8_t* delname, *dpname=NULL; 1339 size_t delnamelen, dpnamelen=0; 1340 struct dns_msg* msg = NULL; 1341 1342 log_query_info(VERB_DETAIL, "resolving", &qstate->qinfo); 1343 /* check effort */ 1344 1345 /* We enforce a maximum number of query restarts. This is primarily a 1346 * cheap way to prevent CNAME loops. */ 1347 if(iq->query_restart_count > ie->max_query_restarts) { 1348 verbose(VERB_QUERY, "request has exceeded the maximum number" 1349 " of query restarts with %d", iq->query_restart_count); 1350 errinf(qstate, "request has exceeded the maximum number " 1351 "restarts (eg. indirections)"); 1352 if(iq->qchase.qname) 1353 errinf_dname(qstate, "stop at", iq->qchase.qname); 1354 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 1355 } 1356 1357 /* We enforce a maximum recursion/dependency depth -- in general, 1358 * this is unnecessary for dependency loops (although it will 1359 * catch those), but it provides a sensible limit to the amount 1360 * of work required to answer a given query. */ 1361 verbose(VERB_ALGO, "request has dependency depth of %d", iq->depth); 1362 if(iq->depth > ie->max_dependency_depth) { 1363 verbose(VERB_QUERY, "request has exceeded the maximum " 1364 "dependency depth with depth of %d", iq->depth); 1365 errinf(qstate, "request has exceeded the maximum dependency " 1366 "depth (eg. nameserver lookup recursion)"); 1367 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 1368 } 1369 1370 /* If the request is qclass=ANY, setup to generate each class */ 1371 if(qstate->qinfo.qclass == LDNS_RR_CLASS_ANY) { 1372 iq->qchase.qclass = 0; 1373 return next_state(iq, COLLECT_CLASS_STATE); 1374 } 1375 1376 /* 1377 * If we are restricted by a forward-zone or a stub-zone, we 1378 * can't re-fetch glue for this delegation point. 1379 * we won’t try to re-fetch glue if the iq->dp is null. 1380 */ 1381 if (iq->refetch_glue && 1382 iq->dp && 1383 !can_have_last_resort(qstate->env, iq->dp->name, 1384 iq->dp->namelen, iq->qchase.qclass, NULL)) { 1385 iq->refetch_glue = 0; 1386 } 1387 1388 /* Resolver Algorithm Step 1 -- Look for the answer in local data. */ 1389 1390 /* This either results in a query restart (CNAME cache response), a 1391 * terminating response (ANSWER), or a cache miss (null). */ 1392 1393 if (iter_stub_fwd_no_cache(qstate, &iq->qchase, &dpname, &dpnamelen)) { 1394 /* Asked to not query cache. */ 1395 verbose(VERB_ALGO, "no-cache set, going to the network"); 1396 qstate->no_cache_lookup = 1; 1397 qstate->no_cache_store = 1; 1398 msg = NULL; 1399 } else if(qstate->blacklist) { 1400 /* if cache, or anything else, was blacklisted then 1401 * getting older results from cache is a bad idea, no cache */ 1402 verbose(VERB_ALGO, "cache blacklisted, going to the network"); 1403 msg = NULL; 1404 } else if(!qstate->no_cache_lookup) { 1405 msg = dns_cache_lookup(qstate->env, iq->qchase.qname, 1406 iq->qchase.qname_len, iq->qchase.qtype, 1407 iq->qchase.qclass, qstate->query_flags, 1408 qstate->region, qstate->env->scratch, 0, dpname, 1409 dpnamelen); 1410 if(!msg && qstate->env->neg_cache && 1411 iter_qname_indicates_dnssec(qstate->env, &iq->qchase)) { 1412 /* lookup in negative cache; may result in 1413 * NOERROR/NODATA or NXDOMAIN answers that need validation */ 1414 msg = val_neg_getmsg(qstate->env->neg_cache, &iq->qchase, 1415 qstate->region, qstate->env->rrset_cache, 1416 qstate->env->scratch_buffer, 1417 *qstate->env->now, 1/*add SOA*/, NULL, 1418 qstate->env->cfg); 1419 } 1420 /* item taken from cache does not match our query name, thus 1421 * security needs to be re-examined later */ 1422 if(msg && query_dname_compare(qstate->qinfo.qname, 1423 iq->qchase.qname) != 0) 1424 msg->rep->security = sec_status_unchecked; 1425 } 1426 if(msg) { 1427 /* handle positive cache response */ 1428 enum response_type type = response_type_from_cache(msg, 1429 &iq->qchase); 1430 if(verbosity >= VERB_ALGO) { 1431 log_dns_msg("msg from cache lookup", &msg->qinfo, 1432 msg->rep); 1433 verbose(VERB_ALGO, "msg ttl is %d, prefetch ttl %d", 1434 (int)msg->rep->ttl, 1435 (int)msg->rep->prefetch_ttl); 1436 } 1437 1438 if(type == RESPONSE_TYPE_CNAME) { 1439 uint8_t* sname = 0; 1440 size_t slen = 0; 1441 verbose(VERB_ALGO, "returning CNAME response from " 1442 "cache"); 1443 if(!handle_cname_response(qstate, iq, msg, 1444 &sname, &slen)) { 1445 errinf(qstate, "failed to prepend CNAME " 1446 "components, malloc failure"); 1447 return error_response(qstate, id, 1448 LDNS_RCODE_SERVFAIL); 1449 } 1450 iq->qchase.qname = sname; 1451 iq->qchase.qname_len = slen; 1452 /* This *is* a query restart, even if it is a cheap 1453 * one. */ 1454 iq->dp = NULL; 1455 iq->refetch_glue = 0; 1456 iq->query_restart_count++; 1457 iq->sent_count = 0; 1458 iq->dp_target_count = 0; 1459 sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region); 1460 if(qstate->env->cfg->qname_minimisation) 1461 iq->minimisation_state = INIT_MINIMISE_STATE; 1462 return next_state(iq, INIT_REQUEST_STATE); 1463 } 1464 1465 /* if from cache, NULL, else insert 'cache IP' len=0 */ 1466 if(qstate->reply_origin) 1467 sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region); 1468 if(FLAGS_GET_RCODE(msg->rep->flags) == LDNS_RCODE_SERVFAIL) 1469 errinf(qstate, "SERVFAIL in cache"); 1470 /* it is an answer, response, to final state */ 1471 verbose(VERB_ALGO, "returning answer from cache."); 1472 iq->response = msg; 1473 return final_state(iq); 1474 } 1475 1476 /* attempt to forward the request */ 1477 if(forward_request(qstate, iq)) 1478 { 1479 if(!iq->dp) { 1480 log_err("alloc failure for forward dp"); 1481 errinf(qstate, "malloc failure for forward zone"); 1482 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 1483 } 1484 if((qstate->query_flags&BIT_RD)==0) { 1485 /* If the server accepts RD=0 queries and forwards 1486 * with RD=1, then if the server is listed as an NS 1487 * entry, it starts query loops. Stop that loop by 1488 * disallowing the query. The RD=0 was previously used 1489 * to check the cache with allow_snoop. For stubs, 1490 * the iterator pass would have primed the stub and 1491 * then cached information can be used for further 1492 * queries. */ 1493 verbose(VERB_ALGO, "cannot forward RD=0 query, to stop query loops"); 1494 errinf(qstate, "cannot forward RD=0 query"); 1495 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 1496 } 1497 iq->refetch_glue = 0; 1498 iq->minimisation_state = DONOT_MINIMISE_STATE; 1499 /* the request has been forwarded. 1500 * forwarded requests need to be immediately sent to the 1501 * next state, QUERYTARGETS. */ 1502 return next_state(iq, QUERYTARGETS_STATE); 1503 } 1504 1505 /* Resolver Algorithm Step 2 -- find the "best" servers. */ 1506 1507 /* first, adjust for DS queries. To avoid the grandparent problem, 1508 * we just look for the closest set of server to the parent of qname. 1509 * When re-fetching glue we also need to ask the parent. 1510 */ 1511 if(iq->refetch_glue) { 1512 if(!iq->dp) { 1513 log_err("internal or malloc fail: no dp for refetch"); 1514 errinf(qstate, "malloc failure, for delegation info"); 1515 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 1516 } 1517 delname = iq->dp->name; 1518 delnamelen = iq->dp->namelen; 1519 } else { 1520 delname = iq->qchase.qname; 1521 delnamelen = iq->qchase.qname_len; 1522 } 1523 if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue || 1524 (iq->qchase.qtype == LDNS_RR_TYPE_NS && qstate->prefetch_leeway 1525 && can_have_last_resort(qstate->env, delname, delnamelen, iq->qchase.qclass, NULL))) { 1526 /* remove first label from delname, root goes to hints, 1527 * but only to fetch glue, not for qtype=DS. */ 1528 /* also when prefetching an NS record, fetch it again from 1529 * its parent, just as if it expired, so that you do not 1530 * get stuck on an older nameserver that gives old NSrecords */ 1531 if(dname_is_root(delname) && (iq->refetch_glue || 1532 (iq->qchase.qtype == LDNS_RR_TYPE_NS && 1533 qstate->prefetch_leeway))) 1534 delname = NULL; /* go to root priming */ 1535 else dname_remove_label(&delname, &delnamelen); 1536 } 1537 /* delname is the name to lookup a delegation for. If NULL rootprime */ 1538 while(1) { 1539 1540 /* Lookup the delegation in the cache. If null, then the 1541 * cache needs to be primed for the qclass. */ 1542 if(delname) 1543 iq->dp = dns_cache_find_delegation(qstate->env, delname, 1544 delnamelen, iq->qchase.qtype, iq->qchase.qclass, 1545 qstate->region, &iq->deleg_msg, 1546 *qstate->env->now+qstate->prefetch_leeway, 1, 1547 dpname, dpnamelen); 1548 else iq->dp = NULL; 1549 1550 /* If the cache has returned nothing, then we have a 1551 * root priming situation. */ 1552 if(iq->dp == NULL) { 1553 int r; 1554 /* if under auth zone, no prime needed */ 1555 if(!auth_zone_delegpt(qstate, iq, delname, delnamelen)) 1556 return error_response(qstate, id, 1557 LDNS_RCODE_SERVFAIL); 1558 if(iq->dp) /* use auth zone dp */ 1559 return next_state(iq, INIT_REQUEST_2_STATE); 1560 /* if there is a stub, then no root prime needed */ 1561 r = prime_stub(qstate, iq, id, delname, 1562 iq->qchase.qclass); 1563 if(r == 2) 1564 break; /* got noprime-stub-zone, continue */ 1565 else if(r) 1566 return 0; /* stub prime request made */ 1567 if(forwards_lookup_root(qstate->env->fwds, 1568 iq->qchase.qclass)) { 1569 /* forward zone root, no root prime needed */ 1570 /* fill in some dp - safety belt */ 1571 iq->dp = hints_lookup_root(qstate->env->hints, 1572 iq->qchase.qclass); 1573 if(!iq->dp) { 1574 log_err("internal error: no hints dp"); 1575 errinf(qstate, "no hints for this class"); 1576 return error_response(qstate, id, 1577 LDNS_RCODE_SERVFAIL); 1578 } 1579 iq->dp = delegpt_copy(iq->dp, qstate->region); 1580 if(!iq->dp) { 1581 log_err("out of memory in safety belt"); 1582 errinf(qstate, "malloc failure, in safety belt"); 1583 return error_response(qstate, id, 1584 LDNS_RCODE_SERVFAIL); 1585 } 1586 return next_state(iq, INIT_REQUEST_2_STATE); 1587 } 1588 /* Note that the result of this will set a new 1589 * DelegationPoint based on the result of priming. */ 1590 if(!prime_root(qstate, iq, id, iq->qchase.qclass)) 1591 return error_response(qstate, id, 1592 LDNS_RCODE_REFUSED); 1593 1594 /* priming creates and sends a subordinate query, with 1595 * this query as the parent. So further processing for 1596 * this event will stop until reactivated by the 1597 * results of priming. */ 1598 return 0; 1599 } 1600 if(!iq->ratelimit_ok && qstate->prefetch_leeway) 1601 iq->ratelimit_ok = 1; /* allow prefetches, this keeps 1602 otherwise valid data in the cache */ 1603 1604 /* see if this dp not useless. 1605 * It is useless if: 1606 * o all NS items are required glue. 1607 * or the query is for NS item that is required glue. 1608 * o no addresses are provided. 1609 * o RD qflag is on. 1610 * Instead, go up one level, and try to get even further 1611 * If the root was useless, use safety belt information. 1612 * Only check cache returns, because replies for servers 1613 * could be useless but lead to loops (bumping into the 1614 * same server reply) if useless-checked. 1615 */ 1616 if(iter_dp_is_useless(&qstate->qinfo, qstate->query_flags, 1617 iq->dp, ie->supports_ipv4, ie->supports_ipv6, 1618 ie->use_nat64)) { 1619 struct delegpt* retdp = NULL; 1620 if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen, iq->qchase.qclass, &retdp)) { 1621 if(retdp) { 1622 verbose(VERB_QUERY, "cache has stub " 1623 "or fwd but no addresses, " 1624 "fallback to config"); 1625 iq->dp = delegpt_copy(retdp, 1626 qstate->region); 1627 if(!iq->dp) { 1628 log_err("out of memory in " 1629 "stub/fwd fallback"); 1630 errinf(qstate, "malloc failure, for fallback to config"); 1631 return error_response(qstate, 1632 id, LDNS_RCODE_SERVFAIL); 1633 } 1634 break; 1635 } 1636 verbose(VERB_ALGO, "useless dp " 1637 "but cannot go up, servfail"); 1638 delegpt_log(VERB_ALGO, iq->dp); 1639 errinf(qstate, "no useful nameservers, " 1640 "and cannot go up"); 1641 errinf_dname(qstate, "for zone", iq->dp->name); 1642 return error_response(qstate, id, 1643 LDNS_RCODE_SERVFAIL); 1644 } 1645 if(dname_is_root(iq->dp->name)) { 1646 /* use safety belt */ 1647 verbose(VERB_QUERY, "Cache has root NS but " 1648 "no addresses. Fallback to the safety belt."); 1649 iq->dp = hints_lookup_root(qstate->env->hints, 1650 iq->qchase.qclass); 1651 /* note deleg_msg is from previous lookup, 1652 * but RD is on, so it is not used */ 1653 if(!iq->dp) { 1654 log_err("internal error: no hints dp"); 1655 return error_response(qstate, id, 1656 LDNS_RCODE_REFUSED); 1657 } 1658 iq->dp = delegpt_copy(iq->dp, qstate->region); 1659 if(!iq->dp) { 1660 log_err("out of memory in safety belt"); 1661 errinf(qstate, "malloc failure, in safety belt, for root"); 1662 return error_response(qstate, id, 1663 LDNS_RCODE_SERVFAIL); 1664 } 1665 break; 1666 } else { 1667 verbose(VERB_ALGO, 1668 "cache delegation was useless:"); 1669 delegpt_log(VERB_ALGO, iq->dp); 1670 /* go up */ 1671 delname = iq->dp->name; 1672 delnamelen = iq->dp->namelen; 1673 dname_remove_label(&delname, &delnamelen); 1674 } 1675 } else break; 1676 } 1677 1678 verbose(VERB_ALGO, "cache delegation returns delegpt"); 1679 delegpt_log(VERB_ALGO, iq->dp); 1680 1681 /* Otherwise, set the current delegation point and move on to the 1682 * next state. */ 1683 return next_state(iq, INIT_REQUEST_2_STATE); 1684 } 1685 1686 /** 1687 * Process the second part of the initial request handling. This state 1688 * basically exists so that queries that generate root priming events have 1689 * the same init processing as ones that do not. Request events that reach 1690 * this state must have a valid currentDelegationPoint set. 1691 * 1692 * This part is primarily handling stub zone priming. Events that reach this 1693 * state must have a current delegation point. 1694 * 1695 * @param qstate: query state. 1696 * @param iq: iterator query state. 1697 * @param id: module id. 1698 * @return true if the event needs more request processing immediately, 1699 * false if not. 1700 */ 1701 static int 1702 processInitRequest2(struct module_qstate* qstate, struct iter_qstate* iq, 1703 int id) 1704 { 1705 uint8_t* delname; 1706 size_t delnamelen; 1707 log_query_info(VERB_QUERY, "resolving (init part 2): ", 1708 &qstate->qinfo); 1709 1710 delname = iq->qchase.qname; 1711 delnamelen = iq->qchase.qname_len; 1712 if(iq->refetch_glue) { 1713 struct iter_hints_stub* stub; 1714 if(!iq->dp) { 1715 log_err("internal or malloc fail: no dp for refetch"); 1716 errinf(qstate, "malloc failure, no delegation info"); 1717 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 1718 } 1719 /* Do not send queries above stub, do not set delname to dp if 1720 * this is above stub without stub-first. */ 1721 stub = hints_lookup_stub( 1722 qstate->env->hints, iq->qchase.qname, iq->qchase.qclass, 1723 iq->dp); 1724 if(!stub || !stub->dp->has_parent_side_NS || 1725 dname_subdomain_c(iq->dp->name, stub->dp->name)) { 1726 delname = iq->dp->name; 1727 delnamelen = iq->dp->namelen; 1728 } 1729 } 1730 if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue) { 1731 if(!dname_is_root(delname)) 1732 dname_remove_label(&delname, &delnamelen); 1733 iq->refetch_glue = 0; /* if CNAME causes restart, no refetch */ 1734 } 1735 1736 /* see if we have an auth zone to answer from, improves dp from cache 1737 * (if any dp from cache) with auth zone dp, if that is lower */ 1738 if(!auth_zone_delegpt(qstate, iq, delname, delnamelen)) 1739 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 1740 1741 /* Check to see if we need to prime a stub zone. */ 1742 if(prime_stub(qstate, iq, id, delname, iq->qchase.qclass)) { 1743 /* A priming sub request was made */ 1744 return 0; 1745 } 1746 1747 /* most events just get forwarded to the next state. */ 1748 return next_state(iq, INIT_REQUEST_3_STATE); 1749 } 1750 1751 /** 1752 * Process the third part of the initial request handling. This state exists 1753 * as a separate state so that queries that generate stub priming events 1754 * will get the tail end of the init process but not repeat the stub priming 1755 * check. 1756 * 1757 * @param qstate: query state. 1758 * @param iq: iterator query state. 1759 * @param id: module id. 1760 * @return true, advancing the event to the QUERYTARGETS_STATE. 1761 */ 1762 static int 1763 processInitRequest3(struct module_qstate* qstate, struct iter_qstate* iq, 1764 int id) 1765 { 1766 log_query_info(VERB_QUERY, "resolving (init part 3): ", 1767 &qstate->qinfo); 1768 /* if the cache reply dp equals a validation anchor or msg has DS, 1769 * then DNSSEC RRSIGs are expected in the reply */ 1770 iq->dnssec_expected = iter_indicates_dnssec(qstate->env, iq->dp, 1771 iq->deleg_msg, iq->qchase.qclass); 1772 1773 /* If the RD flag wasn't set, then we just finish with the 1774 * cached referral as the response. */ 1775 if(!(qstate->query_flags & BIT_RD) && iq->deleg_msg) { 1776 iq->response = iq->deleg_msg; 1777 if(verbosity >= VERB_ALGO && iq->response) 1778 log_dns_msg("no RD requested, using delegation msg", 1779 &iq->response->qinfo, iq->response->rep); 1780 if(qstate->reply_origin) 1781 sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region); 1782 return final_state(iq); 1783 } 1784 /* After this point, unset the RD flag -- this query is going to 1785 * be sent to an auth. server. */ 1786 iq->chase_flags &= ~BIT_RD; 1787 1788 /* if dnssec expected, fetch key for the trust-anchor or cached-DS */ 1789 if(iq->dnssec_expected && qstate->env->cfg->prefetch_key && 1790 !(qstate->query_flags&BIT_CD)) { 1791 generate_dnskey_prefetch(qstate, iq, id); 1792 fptr_ok(fptr_whitelist_modenv_detach_subs( 1793 qstate->env->detach_subs)); 1794 (*qstate->env->detach_subs)(qstate); 1795 } 1796 1797 /* Jump to the next state. */ 1798 return next_state(iq, QUERYTARGETS_STATE); 1799 } 1800 1801 /** 1802 * Given a basic query, generate a parent-side "target" query. 1803 * These are subordinate queries for missing delegation point target addresses, 1804 * for which only the parent of the delegation provides correct IP addresses. 1805 * 1806 * @param qstate: query state. 1807 * @param iq: iterator query state. 1808 * @param id: module id. 1809 * @param name: target qname. 1810 * @param namelen: target qname length. 1811 * @param qtype: target qtype (either A or AAAA). 1812 * @param qclass: target qclass. 1813 * @return true on success, false on failure. 1814 */ 1815 static int 1816 generate_parentside_target_query(struct module_qstate* qstate, 1817 struct iter_qstate* iq, int id, uint8_t* name, size_t namelen, 1818 uint16_t qtype, uint16_t qclass) 1819 { 1820 struct module_qstate* subq; 1821 if(!generate_sub_request(name, namelen, qtype, qclass, qstate, 1822 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0)) 1823 return 0; 1824 if(subq) { 1825 struct iter_qstate* subiq = 1826 (struct iter_qstate*)subq->minfo[id]; 1827 /* blacklist the cache - we want to fetch parent stuff */ 1828 sock_list_insert(&subq->blacklist, NULL, 0, subq->region); 1829 subiq->query_for_pside_glue = 1; 1830 if(dname_subdomain_c(name, iq->dp->name)) { 1831 subiq->dp = delegpt_copy(iq->dp, subq->region); 1832 subiq->dnssec_expected = iter_indicates_dnssec( 1833 qstate->env, subiq->dp, NULL, 1834 subq->qinfo.qclass); 1835 subiq->refetch_glue = 1; 1836 } else { 1837 subiq->dp = dns_cache_find_delegation(qstate->env, 1838 name, namelen, qtype, qclass, subq->region, 1839 &subiq->deleg_msg, 1840 *qstate->env->now+subq->prefetch_leeway, 1841 1, NULL, 0); 1842 /* if no dp, then it's from root, refetch unneeded */ 1843 if(subiq->dp) { 1844 subiq->dnssec_expected = iter_indicates_dnssec( 1845 qstate->env, subiq->dp, NULL, 1846 subq->qinfo.qclass); 1847 subiq->refetch_glue = 1; 1848 } 1849 } 1850 } 1851 log_nametypeclass(VERB_QUERY, "new pside target", name, qtype, qclass); 1852 return 1; 1853 } 1854 1855 /** 1856 * Given a basic query, generate a "target" query. These are subordinate 1857 * queries for missing delegation point target addresses. 1858 * 1859 * @param qstate: query state. 1860 * @param iq: iterator query state. 1861 * @param id: module id. 1862 * @param name: target qname. 1863 * @param namelen: target qname length. 1864 * @param qtype: target qtype (either A or AAAA). 1865 * @param qclass: target qclass. 1866 * @return true on success, false on failure. 1867 */ 1868 static int 1869 generate_target_query(struct module_qstate* qstate, struct iter_qstate* iq, 1870 int id, uint8_t* name, size_t namelen, uint16_t qtype, uint16_t qclass) 1871 { 1872 struct module_qstate* subq; 1873 if(!generate_sub_request(name, namelen, qtype, qclass, qstate, 1874 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0)) 1875 return 0; 1876 log_nametypeclass(VERB_QUERY, "new target", name, qtype, qclass); 1877 return 1; 1878 } 1879 1880 /** 1881 * Given an event at a certain state, generate zero or more target queries 1882 * for it's current delegation point. 1883 * 1884 * @param qstate: query state. 1885 * @param iq: iterator query state. 1886 * @param ie: iterator shared global environment. 1887 * @param id: module id. 1888 * @param maxtargets: The maximum number of targets to query for. 1889 * if it is negative, there is no maximum number of targets. 1890 * @param num: returns the number of queries generated and processed, 1891 * which may be zero if there were no missing targets. 1892 * @return false on error. 1893 */ 1894 static int 1895 query_for_targets(struct module_qstate* qstate, struct iter_qstate* iq, 1896 struct iter_env* ie, int id, int maxtargets, int* num) 1897 { 1898 int query_count = 0; 1899 struct delegpt_ns* ns; 1900 int missing; 1901 int toget = 0; 1902 1903 iter_mark_cycle_targets(qstate, iq->dp); 1904 missing = (int)delegpt_count_missing_targets(iq->dp, NULL); 1905 log_assert(maxtargets != 0); /* that would not be useful */ 1906 1907 /* Generate target requests. Basically, any missing targets 1908 * are queried for here, regardless if it is necessary to do 1909 * so to continue processing. */ 1910 if(maxtargets < 0 || maxtargets > missing) 1911 toget = missing; 1912 else toget = maxtargets; 1913 if(toget == 0) { 1914 *num = 0; 1915 return 1; 1916 } 1917 1918 /* now that we are sure that a target query is going to be made, 1919 * check the limits. */ 1920 if(iq->depth == ie->max_dependency_depth) 1921 return 0; 1922 if(iq->depth > 0 && iq->target_count && 1923 iq->target_count[TARGET_COUNT_QUERIES] > MAX_TARGET_COUNT) { 1924 char s[LDNS_MAX_DOMAINLEN+1]; 1925 dname_str(qstate->qinfo.qname, s); 1926 verbose(VERB_QUERY, "request %s has exceeded the maximum " 1927 "number of glue fetches %d", s, 1928 iq->target_count[TARGET_COUNT_QUERIES]); 1929 return 0; 1930 } 1931 if(iq->dp_target_count > MAX_DP_TARGET_COUNT) { 1932 char s[LDNS_MAX_DOMAINLEN+1]; 1933 dname_str(qstate->qinfo.qname, s); 1934 verbose(VERB_QUERY, "request %s has exceeded the maximum " 1935 "number of glue fetches %d to a single delegation point", 1936 s, iq->dp_target_count); 1937 return 0; 1938 } 1939 1940 /* select 'toget' items from the total of 'missing' items */ 1941 log_assert(toget <= missing); 1942 1943 /* loop over missing targets */ 1944 for(ns = iq->dp->nslist; ns; ns = ns->next) { 1945 if(ns->resolved) 1946 continue; 1947 1948 /* randomly select this item with probability toget/missing */ 1949 if(!iter_ns_probability(qstate->env->rnd, toget, missing)) { 1950 /* do not select this one, next; select toget number 1951 * of items from a list one less in size */ 1952 missing --; 1953 continue; 1954 } 1955 1956 if(ie->supports_ipv6 && 1957 ((ns->lame && !ns->done_pside6) || 1958 (!ns->lame && !ns->got6))) { 1959 /* Send the AAAA request. */ 1960 if(!generate_target_query(qstate, iq, id, 1961 ns->name, ns->namelen, 1962 LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) { 1963 *num = query_count; 1964 if(query_count > 0) 1965 qstate->ext_state[id] = module_wait_subquery; 1966 return 0; 1967 } 1968 query_count++; 1969 /* If the mesh query list is full, exit the loop here. 1970 * This makes the routine spawn one query at a time, 1971 * and this means there is no query state load 1972 * increase, because the spawned state uses cpu and a 1973 * socket while this state waits for that spawned 1974 * state. Next time we can look up further targets */ 1975 if(mesh_jostle_exceeded(qstate->env->mesh)) 1976 break; 1977 } 1978 /* Send the A request. */ 1979 if((ie->supports_ipv4 || ie->use_nat64) && 1980 ((ns->lame && !ns->done_pside4) || 1981 (!ns->lame && !ns->got4))) { 1982 if(!generate_target_query(qstate, iq, id, 1983 ns->name, ns->namelen, 1984 LDNS_RR_TYPE_A, iq->qchase.qclass)) { 1985 *num = query_count; 1986 if(query_count > 0) 1987 qstate->ext_state[id] = module_wait_subquery; 1988 return 0; 1989 } 1990 query_count++; 1991 /* If the mesh query list is full, exit the loop. */ 1992 if(mesh_jostle_exceeded(qstate->env->mesh)) 1993 break; 1994 } 1995 1996 /* mark this target as in progress. */ 1997 ns->resolved = 1; 1998 missing--; 1999 toget--; 2000 if(toget == 0) 2001 break; 2002 } 2003 *num = query_count; 2004 if(query_count > 0) 2005 qstate->ext_state[id] = module_wait_subquery; 2006 2007 return 1; 2008 } 2009 2010 /** 2011 * Called by processQueryTargets when it would like extra targets to query 2012 * but it seems to be out of options. At last resort some less appealing 2013 * options are explored. If there are no more options, the result is SERVFAIL 2014 * 2015 * @param qstate: query state. 2016 * @param iq: iterator query state. 2017 * @param ie: iterator shared global environment. 2018 * @param id: module id. 2019 * @return true if the event requires more request processing immediately, 2020 * false if not. 2021 */ 2022 static int 2023 processLastResort(struct module_qstate* qstate, struct iter_qstate* iq, 2024 struct iter_env* ie, int id) 2025 { 2026 struct delegpt_ns* ns; 2027 int query_count = 0; 2028 verbose(VERB_ALGO, "No more query targets, attempting last resort"); 2029 log_assert(iq->dp); 2030 2031 if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen, 2032 iq->qchase.qclass, NULL)) { 2033 /* fail -- no more targets, no more hope of targets, no hope 2034 * of a response. */ 2035 errinf(qstate, "all the configured stub or forward servers failed,"); 2036 errinf_dname(qstate, "at zone", iq->dp->name); 2037 errinf_reply(qstate, iq); 2038 verbose(VERB_QUERY, "configured stub or forward servers failed -- returning SERVFAIL"); 2039 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL); 2040 } 2041 if(!iq->dp->has_parent_side_NS && dname_is_root(iq->dp->name)) { 2042 struct delegpt* p = hints_lookup_root(qstate->env->hints, 2043 iq->qchase.qclass); 2044 if(p) { 2045 struct delegpt_addr* a; 2046 iq->chase_flags &= ~BIT_RD; /* go to authorities */ 2047 for(ns = p->nslist; ns; ns=ns->next) { 2048 (void)delegpt_add_ns(iq->dp, qstate->region, 2049 ns->name, ns->lame, ns->tls_auth_name, 2050 ns->port); 2051 } 2052 for(a = p->target_list; a; a=a->next_target) { 2053 (void)delegpt_add_addr(iq->dp, qstate->region, 2054 &a->addr, a->addrlen, a->bogus, 2055 a->lame, a->tls_auth_name, -1, NULL); 2056 } 2057 } 2058 iq->dp->has_parent_side_NS = 1; 2059 } else if(!iq->dp->has_parent_side_NS) { 2060 if(!iter_lookup_parent_NS_from_cache(qstate->env, iq->dp, 2061 qstate->region, &qstate->qinfo) 2062 || !iq->dp->has_parent_side_NS) { 2063 /* if: malloc failure in lookup go up to try */ 2064 /* if: no parent NS in cache - go up one level */ 2065 verbose(VERB_ALGO, "try to grab parent NS"); 2066 iq->store_parent_NS = iq->dp; 2067 iq->chase_flags &= ~BIT_RD; /* go to authorities */ 2068 iq->deleg_msg = NULL; 2069 iq->refetch_glue = 1; 2070 iq->query_restart_count++; 2071 iq->sent_count = 0; 2072 iq->dp_target_count = 0; 2073 if(qstate->env->cfg->qname_minimisation) 2074 iq->minimisation_state = INIT_MINIMISE_STATE; 2075 return next_state(iq, INIT_REQUEST_STATE); 2076 } 2077 } 2078 /* see if that makes new names available */ 2079 if(!cache_fill_missing(qstate->env, iq->qchase.qclass, 2080 qstate->region, iq->dp)) 2081 log_err("out of memory in cache_fill_missing"); 2082 if(iq->dp->usable_list) { 2083 verbose(VERB_ALGO, "try parent-side-name, w. glue from cache"); 2084 return next_state(iq, QUERYTARGETS_STATE); 2085 } 2086 /* try to fill out parent glue from cache */ 2087 if(iter_lookup_parent_glue_from_cache(qstate->env, iq->dp, 2088 qstate->region, &qstate->qinfo)) { 2089 /* got parent stuff from cache, see if we can continue */ 2090 verbose(VERB_ALGO, "try parent-side glue from cache"); 2091 return next_state(iq, QUERYTARGETS_STATE); 2092 } 2093 /* query for an extra name added by the parent-NS record */ 2094 if(delegpt_count_missing_targets(iq->dp, NULL) > 0) { 2095 int qs = 0; 2096 verbose(VERB_ALGO, "try parent-side target name"); 2097 if(!query_for_targets(qstate, iq, ie, id, 1, &qs)) { 2098 errinf(qstate, "could not fetch nameserver"); 2099 errinf_dname(qstate, "at zone", iq->dp->name); 2100 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2101 } 2102 iq->num_target_queries += qs; 2103 target_count_increase(iq, qs); 2104 if(qs != 0) { 2105 qstate->ext_state[id] = module_wait_subquery; 2106 return 0; /* and wait for them */ 2107 } 2108 } 2109 if(iq->depth == ie->max_dependency_depth) { 2110 verbose(VERB_QUERY, "maxdepth and need more nameservers, fail"); 2111 errinf(qstate, "cannot fetch more nameservers because at max dependency depth"); 2112 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL); 2113 } 2114 if(iq->depth > 0 && iq->target_count && 2115 iq->target_count[TARGET_COUNT_QUERIES] > MAX_TARGET_COUNT) { 2116 char s[LDNS_MAX_DOMAINLEN+1]; 2117 dname_str(qstate->qinfo.qname, s); 2118 verbose(VERB_QUERY, "request %s has exceeded the maximum " 2119 "number of glue fetches %d", s, 2120 iq->target_count[TARGET_COUNT_QUERIES]); 2121 errinf(qstate, "exceeded the maximum number of glue fetches"); 2122 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL); 2123 } 2124 /* mark cycle targets for parent-side lookups */ 2125 iter_mark_pside_cycle_targets(qstate, iq->dp); 2126 /* see if we can issue queries to get nameserver addresses */ 2127 /* this lookup is not randomized, but sequential. */ 2128 for(ns = iq->dp->nslist; ns; ns = ns->next) { 2129 /* if this nameserver is at a delegation point, but that 2130 * delegation point is a stub and we cannot go higher, skip*/ 2131 if( ((ie->supports_ipv6 && !ns->done_pside6) || 2132 ((ie->supports_ipv4 || ie->use_nat64) && !ns->done_pside4)) && 2133 !can_have_last_resort(qstate->env, ns->name, ns->namelen, 2134 iq->qchase.qclass, NULL)) { 2135 log_nametypeclass(VERB_ALGO, "cannot pside lookup ns " 2136 "because it is also a stub/forward,", 2137 ns->name, LDNS_RR_TYPE_NS, iq->qchase.qclass); 2138 if(ie->supports_ipv6) ns->done_pside6 = 1; 2139 if(ie->supports_ipv4 || ie->use_nat64) ns->done_pside4 = 1; 2140 continue; 2141 } 2142 /* query for parent-side A and AAAA for nameservers */ 2143 if(ie->supports_ipv6 && !ns->done_pside6) { 2144 /* Send the AAAA request. */ 2145 if(!generate_parentside_target_query(qstate, iq, id, 2146 ns->name, ns->namelen, 2147 LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) { 2148 errinf_dname(qstate, "could not generate nameserver AAAA lookup for", ns->name); 2149 return error_response(qstate, id, 2150 LDNS_RCODE_SERVFAIL); 2151 } 2152 ns->done_pside6 = 1; 2153 query_count++; 2154 if(mesh_jostle_exceeded(qstate->env->mesh)) { 2155 /* Wait for the lookup; do not spawn multiple 2156 * lookups at a time. */ 2157 verbose(VERB_ALGO, "try parent-side glue lookup"); 2158 iq->num_target_queries += query_count; 2159 target_count_increase(iq, query_count); 2160 qstate->ext_state[id] = module_wait_subquery; 2161 return 0; 2162 } 2163 } 2164 if((ie->supports_ipv4 || ie->use_nat64) && !ns->done_pside4) { 2165 /* Send the A request. */ 2166 if(!generate_parentside_target_query(qstate, iq, id, 2167 ns->name, ns->namelen, 2168 LDNS_RR_TYPE_A, iq->qchase.qclass)) { 2169 errinf_dname(qstate, "could not generate nameserver A lookup for", ns->name); 2170 return error_response(qstate, id, 2171 LDNS_RCODE_SERVFAIL); 2172 } 2173 ns->done_pside4 = 1; 2174 query_count++; 2175 } 2176 if(query_count != 0) { /* suspend to await results */ 2177 verbose(VERB_ALGO, "try parent-side glue lookup"); 2178 iq->num_target_queries += query_count; 2179 target_count_increase(iq, query_count); 2180 qstate->ext_state[id] = module_wait_subquery; 2181 return 0; 2182 } 2183 } 2184 2185 /* if this was a parent-side glue query itself, then store that 2186 * failure in cache. */ 2187 if(!qstate->no_cache_store && iq->query_for_pside_glue 2188 && !iq->pside_glue) 2189 iter_store_parentside_neg(qstate->env, &qstate->qinfo, 2190 iq->deleg_msg?iq->deleg_msg->rep: 2191 (iq->response?iq->response->rep:NULL)); 2192 2193 errinf(qstate, "all servers for this domain failed,"); 2194 errinf_dname(qstate, "at zone", iq->dp->name); 2195 errinf_reply(qstate, iq); 2196 verbose(VERB_QUERY, "out of query targets -- returning SERVFAIL"); 2197 /* fail -- no more targets, no more hope of targets, no hope 2198 * of a response. */ 2199 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL); 2200 } 2201 2202 /** 2203 * Try to find the NS record set that will resolve a qtype DS query. Due 2204 * to grandparent/grandchild reasons we did not get a proper lookup right 2205 * away. We need to create type NS queries until we get the right parent 2206 * for this lookup. We remove labels from the query to find the right point. 2207 * If we end up at the old dp name, then there is no solution. 2208 * 2209 * @param qstate: query state. 2210 * @param iq: iterator query state. 2211 * @param id: module id. 2212 * @return true if the event requires more immediate processing, false if 2213 * not. This is generally only true when forwarding the request to 2214 * the final state (i.e., on answer). 2215 */ 2216 static int 2217 processDSNSFind(struct module_qstate* qstate, struct iter_qstate* iq, int id) 2218 { 2219 struct module_qstate* subq = NULL; 2220 verbose(VERB_ALGO, "processDSNSFind"); 2221 2222 if(!iq->dsns_point) { 2223 /* initialize */ 2224 iq->dsns_point = iq->qchase.qname; 2225 iq->dsns_point_len = iq->qchase.qname_len; 2226 } 2227 /* robustcheck for internal error: we are not underneath the dp */ 2228 if(!dname_subdomain_c(iq->dsns_point, iq->dp->name)) { 2229 errinf_dname(qstate, "for DS query parent-child nameserver search the query is not under the zone", iq->dp->name); 2230 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL); 2231 } 2232 2233 /* go up one (more) step, until we hit the dp, if so, end */ 2234 dname_remove_label(&iq->dsns_point, &iq->dsns_point_len); 2235 if(query_dname_compare(iq->dsns_point, iq->dp->name) == 0) { 2236 /* there was no inbetween nameserver, use the old delegation 2237 * point again. And this time, because dsns_point is nonNULL 2238 * we are going to accept the (bad) result */ 2239 iq->state = QUERYTARGETS_STATE; 2240 return 1; 2241 } 2242 iq->state = DSNS_FIND_STATE; 2243 2244 /* spawn NS lookup (validation not needed, this is for DS lookup) */ 2245 log_nametypeclass(VERB_ALGO, "fetch nameservers", 2246 iq->dsns_point, LDNS_RR_TYPE_NS, iq->qchase.qclass); 2247 if(!generate_sub_request(iq->dsns_point, iq->dsns_point_len, 2248 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq, 2249 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0)) { 2250 errinf_dname(qstate, "for DS query parent-child nameserver search, could not generate NS lookup for", iq->dsns_point); 2251 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL); 2252 } 2253 2254 return 0; 2255 } 2256 2257 /** 2258 * Check if we wait responses for sent queries and update the iterator's 2259 * external state. 2260 */ 2261 static void 2262 check_waiting_queries(struct iter_qstate* iq, struct module_qstate* qstate, 2263 int id) 2264 { 2265 if(iq->num_target_queries>0 && iq->num_current_queries>0) { 2266 verbose(VERB_ALGO, "waiting for %d targets to " 2267 "resolve or %d outstanding queries to " 2268 "respond", iq->num_target_queries, 2269 iq->num_current_queries); 2270 qstate->ext_state[id] = module_wait_reply; 2271 } else if(iq->num_target_queries>0) { 2272 verbose(VERB_ALGO, "waiting for %d targets to " 2273 "resolve", iq->num_target_queries); 2274 qstate->ext_state[id] = module_wait_subquery; 2275 } else { 2276 verbose(VERB_ALGO, "waiting for %d " 2277 "outstanding queries to respond", 2278 iq->num_current_queries); 2279 qstate->ext_state[id] = module_wait_reply; 2280 } 2281 } 2282 2283 /** 2284 * This is the request event state where the request will be sent to one of 2285 * its current query targets. This state also handles issuing target lookup 2286 * queries for missing target IP addresses. Queries typically iterate on 2287 * this state, both when they are just trying different targets for a given 2288 * delegation point, and when they change delegation points. This state 2289 * roughly corresponds to RFC 1034 algorithm steps 3 and 4. 2290 * 2291 * @param qstate: query state. 2292 * @param iq: iterator query state. 2293 * @param ie: iterator shared global environment. 2294 * @param id: module id. 2295 * @return true if the event requires more request processing immediately, 2296 * false if not. This state only returns true when it is generating 2297 * a SERVFAIL response because the query has hit a dead end. 2298 */ 2299 static int 2300 processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq, 2301 struct iter_env* ie, int id) 2302 { 2303 int tf_policy; 2304 struct delegpt_addr* target; 2305 struct outbound_entry* outq; 2306 struct sockaddr_storage real_addr; 2307 socklen_t real_addrlen; 2308 int auth_fallback = 0; 2309 uint8_t* qout_orig = NULL; 2310 size_t qout_orig_len = 0; 2311 int sq_check_ratelimit = 1; 2312 int sq_was_ratelimited = 0; 2313 int can_do_promisc = 0; 2314 2315 /* NOTE: a request will encounter this state for each target it 2316 * needs to send a query to. That is, at least one per referral, 2317 * more if some targets timeout or return throwaway answers. */ 2318 2319 log_query_info(VERB_QUERY, "processQueryTargets:", &qstate->qinfo); 2320 verbose(VERB_ALGO, "processQueryTargets: targetqueries %d, " 2321 "currentqueries %d sentcount %d", iq->num_target_queries, 2322 iq->num_current_queries, iq->sent_count); 2323 2324 /* Make sure that we haven't run away */ 2325 if(iq->referral_count > MAX_REFERRAL_COUNT) { 2326 verbose(VERB_QUERY, "request has exceeded the maximum " 2327 "number of referrrals with %d", iq->referral_count); 2328 errinf(qstate, "exceeded the maximum of referrals"); 2329 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2330 } 2331 if(iq->sent_count > ie->max_sent_count) { 2332 verbose(VERB_QUERY, "request has exceeded the maximum " 2333 "number of sends with %d", iq->sent_count); 2334 errinf(qstate, "exceeded the maximum number of sends"); 2335 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2336 } 2337 2338 /* Check if we reached MAX_TARGET_NX limit without a fallback activation. */ 2339 if(iq->target_count && !*iq->nxns_dp && 2340 iq->target_count[TARGET_COUNT_NX] > MAX_TARGET_NX) { 2341 struct delegpt_ns* ns; 2342 /* If we can wait for resolution, do so. */ 2343 if(iq->num_target_queries>0 || iq->num_current_queries>0) { 2344 check_waiting_queries(iq, qstate, id); 2345 return 0; 2346 } 2347 verbose(VERB_ALGO, "request has exceeded the maximum " 2348 "number of nxdomain nameserver lookups (%d) with %d", 2349 MAX_TARGET_NX, iq->target_count[TARGET_COUNT_NX]); 2350 /* Check for dp because we require one below */ 2351 if(!iq->dp) { 2352 verbose(VERB_QUERY, "Failed to get a delegation, " 2353 "giving up"); 2354 errinf(qstate, "failed to get a delegation (eg. prime " 2355 "failure)"); 2356 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2357 } 2358 /* We reached the limit but we already have parent side 2359 * information; stop resolution */ 2360 if(iq->dp->has_parent_side_NS) { 2361 verbose(VERB_ALGO, "parent-side information is " 2362 "already present for the delegation point, no " 2363 "fallback possible"); 2364 errinf(qstate, "exceeded the maximum nameserver nxdomains"); 2365 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2366 } 2367 verbose(VERB_ALGO, "initiating parent-side fallback for " 2368 "nxdomain nameserver lookups"); 2369 /* Mark all the current NSes as resolved to allow for parent 2370 * fallback */ 2371 for(ns=iq->dp->nslist; ns; ns=ns->next) { 2372 ns->resolved = 1; 2373 } 2374 /* Note the delegation point that triggered the NXNS fallback; 2375 * no reason for shared queries to keep trying there. 2376 * This also marks the fallback activation. */ 2377 *iq->nxns_dp = malloc(iq->dp->namelen); 2378 if(!*iq->nxns_dp) { 2379 verbose(VERB_ALGO, "out of memory while initiating " 2380 "fallback"); 2381 errinf(qstate, "exceeded the maximum nameserver " 2382 "nxdomains (malloc)"); 2383 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2384 } 2385 memcpy(*iq->nxns_dp, iq->dp->name, iq->dp->namelen); 2386 } else if(iq->target_count && *iq->nxns_dp) { 2387 /* Handle the NXNS fallback case. */ 2388 /* If we can wait for resolution, do so. */ 2389 if(iq->num_target_queries>0 || iq->num_current_queries>0) { 2390 check_waiting_queries(iq, qstate, id); 2391 return 0; 2392 } 2393 /* Check for dp because we require one below */ 2394 if(!iq->dp) { 2395 verbose(VERB_QUERY, "Failed to get a delegation, " 2396 "giving up"); 2397 errinf(qstate, "failed to get a delegation (eg. prime " 2398 "failure)"); 2399 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2400 } 2401 2402 if(iq->target_count[TARGET_COUNT_NX] > MAX_TARGET_NX_FALLBACK) { 2403 verbose(VERB_ALGO, "request has exceeded the maximum " 2404 "number of fallback nxdomain nameserver " 2405 "lookups (%d) with %d", MAX_TARGET_NX_FALLBACK, 2406 iq->target_count[TARGET_COUNT_NX]); 2407 errinf(qstate, "exceeded the maximum nameserver nxdomains"); 2408 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2409 } 2410 2411 if(!iq->dp->has_parent_side_NS) { 2412 struct delegpt_ns* ns; 2413 if(!dname_canonical_compare(*iq->nxns_dp, iq->dp->name)) { 2414 verbose(VERB_ALGO, "this delegation point " 2415 "initiated the fallback, marking the " 2416 "nslist as resolved"); 2417 for(ns=iq->dp->nslist; ns; ns=ns->next) { 2418 ns->resolved = 1; 2419 } 2420 } 2421 } 2422 } 2423 2424 /* Make sure we have a delegation point, otherwise priming failed 2425 * or another failure occurred */ 2426 if(!iq->dp) { 2427 verbose(VERB_QUERY, "Failed to get a delegation, giving up"); 2428 errinf(qstate, "failed to get a delegation (eg. prime failure)"); 2429 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2430 } 2431 if(!ie->supports_ipv6) 2432 delegpt_no_ipv6(iq->dp); 2433 if(!ie->supports_ipv4 && !ie->use_nat64) 2434 delegpt_no_ipv4(iq->dp); 2435 delegpt_log(VERB_ALGO, iq->dp); 2436 2437 if(iq->num_current_queries>0) { 2438 /* already busy answering a query, this restart is because 2439 * more delegpt addrs became available, wait for existing 2440 * query. */ 2441 verbose(VERB_ALGO, "woke up, but wait for outstanding query"); 2442 qstate->ext_state[id] = module_wait_reply; 2443 return 0; 2444 } 2445 2446 if(iq->minimisation_state == INIT_MINIMISE_STATE 2447 && !(iq->chase_flags & BIT_RD)) { 2448 /* (Re)set qinfo_out to (new) delegation point, except when 2449 * qinfo_out is already a subdomain of dp. This happens when 2450 * increasing by more than one label at once (QNAMEs with more 2451 * than MAX_MINIMISE_COUNT labels). */ 2452 if(!(iq->qinfo_out.qname_len 2453 && dname_subdomain_c(iq->qchase.qname, 2454 iq->qinfo_out.qname) 2455 && dname_subdomain_c(iq->qinfo_out.qname, 2456 iq->dp->name))) { 2457 iq->qinfo_out.qname = iq->dp->name; 2458 iq->qinfo_out.qname_len = iq->dp->namelen; 2459 iq->qinfo_out.qtype = LDNS_RR_TYPE_A; 2460 iq->qinfo_out.qclass = iq->qchase.qclass; 2461 iq->qinfo_out.local_alias = NULL; 2462 iq->minimise_count = 0; 2463 } 2464 2465 iq->minimisation_state = MINIMISE_STATE; 2466 } 2467 if(iq->minimisation_state == MINIMISE_STATE) { 2468 int qchaselabs = dname_count_labels(iq->qchase.qname); 2469 int labdiff = qchaselabs - 2470 dname_count_labels(iq->qinfo_out.qname); 2471 2472 qout_orig = iq->qinfo_out.qname; 2473 qout_orig_len = iq->qinfo_out.qname_len; 2474 iq->qinfo_out.qname = iq->qchase.qname; 2475 iq->qinfo_out.qname_len = iq->qchase.qname_len; 2476 iq->minimise_count++; 2477 iq->timeout_count = 0; 2478 2479 iter_dec_attempts(iq->dp, 1, ie->outbound_msg_retry); 2480 2481 /* Limit number of iterations for QNAMEs with more 2482 * than MAX_MINIMISE_COUNT labels. Send first MINIMISE_ONE_LAB 2483 * labels of QNAME always individually. 2484 */ 2485 if(qchaselabs > MAX_MINIMISE_COUNT && labdiff > 1 && 2486 iq->minimise_count > MINIMISE_ONE_LAB) { 2487 if(iq->minimise_count < MAX_MINIMISE_COUNT) { 2488 int multilabs = qchaselabs - 1 - 2489 MINIMISE_ONE_LAB; 2490 int extralabs = multilabs / 2491 MINIMISE_MULTIPLE_LABS; 2492 2493 if (MAX_MINIMISE_COUNT - iq->minimise_count >= 2494 multilabs % MINIMISE_MULTIPLE_LABS) 2495 /* Default behaviour is to add 1 label 2496 * every iteration. Therefore, decrement 2497 * the extralabs by 1 */ 2498 extralabs--; 2499 if (extralabs < labdiff) 2500 labdiff -= extralabs; 2501 else 2502 labdiff = 1; 2503 } 2504 /* Last minimised iteration, send all labels with 2505 * QTYPE=NS */ 2506 else 2507 labdiff = 1; 2508 } 2509 2510 if(labdiff > 1) { 2511 verbose(VERB_QUERY, "removing %d labels", labdiff-1); 2512 dname_remove_labels(&iq->qinfo_out.qname, 2513 &iq->qinfo_out.qname_len, 2514 labdiff-1); 2515 } 2516 if(labdiff < 1 || (labdiff < 2 2517 && (iq->qchase.qtype == LDNS_RR_TYPE_DS 2518 || iq->qchase.qtype == LDNS_RR_TYPE_A))) 2519 /* Stop minimising this query, resolve "as usual" */ 2520 iq->minimisation_state = DONOT_MINIMISE_STATE; 2521 else if(!qstate->no_cache_lookup) { 2522 struct dns_msg* msg = dns_cache_lookup(qstate->env, 2523 iq->qinfo_out.qname, iq->qinfo_out.qname_len, 2524 iq->qinfo_out.qtype, iq->qinfo_out.qclass, 2525 qstate->query_flags, qstate->region, 2526 qstate->env->scratch, 0, iq->dp->name, 2527 iq->dp->namelen); 2528 if(msg && FLAGS_GET_RCODE(msg->rep->flags) == 2529 LDNS_RCODE_NOERROR) 2530 /* no need to send query if it is already 2531 * cached as NOERROR */ 2532 return 1; 2533 if(msg && FLAGS_GET_RCODE(msg->rep->flags) == 2534 LDNS_RCODE_NXDOMAIN && 2535 qstate->env->need_to_validate && 2536 qstate->env->cfg->harden_below_nxdomain) { 2537 if(msg->rep->security == sec_status_secure) { 2538 iq->response = msg; 2539 return final_state(iq); 2540 } 2541 if(msg->rep->security == sec_status_unchecked) { 2542 struct module_qstate* subq = NULL; 2543 if(!generate_sub_request( 2544 iq->qinfo_out.qname, 2545 iq->qinfo_out.qname_len, 2546 iq->qinfo_out.qtype, 2547 iq->qinfo_out.qclass, 2548 qstate, id, iq, 2549 INIT_REQUEST_STATE, 2550 FINISHED_STATE, &subq, 1, 1)) 2551 verbose(VERB_ALGO, 2552 "could not validate NXDOMAIN " 2553 "response"); 2554 } 2555 } 2556 if(msg && FLAGS_GET_RCODE(msg->rep->flags) == 2557 LDNS_RCODE_NXDOMAIN) { 2558 /* return and add a label in the next 2559 * minimisation iteration. 2560 */ 2561 return 1; 2562 } 2563 } 2564 } 2565 if(iq->minimisation_state == SKIP_MINIMISE_STATE) { 2566 if(iq->timeout_count < MAX_MINIMISE_TIMEOUT_COUNT) 2567 /* Do not increment qname, continue incrementing next 2568 * iteration */ 2569 iq->minimisation_state = MINIMISE_STATE; 2570 else if(!qstate->env->cfg->qname_minimisation_strict) 2571 /* Too many time-outs detected for this QNAME and QTYPE. 2572 * We give up, disable QNAME minimisation. */ 2573 iq->minimisation_state = DONOT_MINIMISE_STATE; 2574 } 2575 if(iq->minimisation_state == DONOT_MINIMISE_STATE) 2576 iq->qinfo_out = iq->qchase; 2577 2578 /* now find an answer to this query */ 2579 /* see if authority zones have an answer */ 2580 /* now we know the dp, we can check the auth zone for locally hosted 2581 * contents */ 2582 if(!iq->auth_zone_avoid && qstate->blacklist) { 2583 if(auth_zones_can_fallback(qstate->env->auth_zones, 2584 iq->dp->name, iq->dp->namelen, iq->qinfo_out.qclass)) { 2585 /* if cache is blacklisted and this zone allows us 2586 * to fallback to the internet, then do so, and 2587 * fetch results from the internet servers */ 2588 iq->auth_zone_avoid = 1; 2589 } 2590 } 2591 if(iq->auth_zone_avoid) { 2592 iq->auth_zone_avoid = 0; 2593 auth_fallback = 1; 2594 } else if(auth_zones_lookup(qstate->env->auth_zones, &iq->qinfo_out, 2595 qstate->region, &iq->response, &auth_fallback, iq->dp->name, 2596 iq->dp->namelen)) { 2597 /* use this as a response to be processed by the iterator */ 2598 if(verbosity >= VERB_ALGO) { 2599 log_dns_msg("msg from auth zone", 2600 &iq->response->qinfo, iq->response->rep); 2601 } 2602 if((iq->chase_flags&BIT_RD) && !(iq->response->rep->flags&BIT_AA)) { 2603 verbose(VERB_ALGO, "forwarder, ignoring referral from auth zone"); 2604 } else { 2605 lock_rw_wrlock(&qstate->env->auth_zones->lock); 2606 qstate->env->auth_zones->num_query_up++; 2607 lock_rw_unlock(&qstate->env->auth_zones->lock); 2608 iq->num_current_queries++; 2609 iq->chase_to_rd = 0; 2610 iq->dnssec_lame_query = 0; 2611 iq->auth_zone_response = 1; 2612 return next_state(iq, QUERY_RESP_STATE); 2613 } 2614 } 2615 iq->auth_zone_response = 0; 2616 if(auth_fallback == 0) { 2617 /* like we got servfail from the auth zone lookup, and 2618 * no internet fallback */ 2619 verbose(VERB_ALGO, "auth zone lookup failed, no fallback," 2620 " servfail"); 2621 errinf(qstate, "auth zone lookup failed, fallback is off"); 2622 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2623 } 2624 if(iq->dp->auth_dp) { 2625 /* we wanted to fallback, but had no delegpt, only the 2626 * auth zone generated delegpt, create an actual one */ 2627 iq->auth_zone_avoid = 1; 2628 return next_state(iq, INIT_REQUEST_STATE); 2629 } 2630 /* but mostly, fallback==1 (like, when no such auth zone exists) 2631 * and we continue with lookups */ 2632 2633 tf_policy = 0; 2634 /* < not <=, because although the array is large enough for <=, the 2635 * generated query will immediately be discarded due to depth and 2636 * that servfail is cached, which is not good as opportunism goes. */ 2637 if(iq->depth < ie->max_dependency_depth 2638 && iq->num_target_queries == 0 2639 && (!iq->target_count || iq->target_count[TARGET_COUNT_NX]==0) 2640 && iq->sent_count < TARGET_FETCH_STOP) { 2641 can_do_promisc = 1; 2642 } 2643 /* if the mesh query list is full, then do not waste cpu and sockets to 2644 * fetch promiscuous targets. They can be looked up when needed. */ 2645 if(can_do_promisc && !mesh_jostle_exceeded(qstate->env->mesh)) { 2646 tf_policy = ie->target_fetch_policy[iq->depth]; 2647 } 2648 2649 /* if in 0x20 fallback get as many targets as possible */ 2650 if(iq->caps_fallback) { 2651 int extra = 0; 2652 size_t naddr, nres, navail; 2653 if(!query_for_targets(qstate, iq, ie, id, -1, &extra)) { 2654 errinf(qstate, "could not fetch nameservers for 0x20 fallback"); 2655 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2656 } 2657 iq->num_target_queries += extra; 2658 target_count_increase(iq, extra); 2659 if(iq->num_target_queries > 0) { 2660 /* wait to get all targets, we want to try em */ 2661 verbose(VERB_ALGO, "wait for all targets for fallback"); 2662 qstate->ext_state[id] = module_wait_reply; 2663 /* undo qname minimise step because we'll get back here 2664 * to do it again */ 2665 if(qout_orig && iq->minimise_count > 0) { 2666 iq->minimise_count--; 2667 iq->qinfo_out.qname = qout_orig; 2668 iq->qinfo_out.qname_len = qout_orig_len; 2669 } 2670 return 0; 2671 } 2672 /* did we do enough fallback queries already? */ 2673 delegpt_count_addr(iq->dp, &naddr, &nres, &navail); 2674 /* the current caps_server is the number of fallbacks sent. 2675 * the original query is one that matched too, so we have 2676 * caps_server+1 number of matching queries now */ 2677 if(iq->caps_server+1 >= naddr*3 || 2678 iq->caps_server*2+2 >= (size_t)ie->max_sent_count) { 2679 /* *2 on sentcount check because ipv6 may fail */ 2680 /* we're done, process the response */ 2681 verbose(VERB_ALGO, "0x20 fallback had %d responses " 2682 "match for %d wanted, done.", 2683 (int)iq->caps_server+1, (int)naddr*3); 2684 iq->response = iq->caps_response; 2685 iq->caps_fallback = 0; 2686 iter_dec_attempts(iq->dp, 3, ie->outbound_msg_retry); /* space for fallback */ 2687 iq->num_current_queries++; /* RespState decrements it*/ 2688 iq->referral_count++; /* make sure we don't loop */ 2689 iq->sent_count = 0; 2690 iq->dp_target_count = 0; 2691 iq->state = QUERY_RESP_STATE; 2692 return 1; 2693 } 2694 verbose(VERB_ALGO, "0x20 fallback number %d", 2695 (int)iq->caps_server); 2696 2697 /* if there is a policy to fetch missing targets 2698 * opportunistically, do it. we rely on the fact that once a 2699 * query (or queries) for a missing name have been issued, 2700 * they will not show up again. */ 2701 } else if(tf_policy != 0) { 2702 int extra = 0; 2703 verbose(VERB_ALGO, "attempt to get extra %d targets", 2704 tf_policy); 2705 (void)query_for_targets(qstate, iq, ie, id, tf_policy, &extra); 2706 /* errors ignored, these targets are not strictly necessary for 2707 * this result, we do not have to reply with SERVFAIL */ 2708 iq->num_target_queries += extra; 2709 target_count_increase(iq, extra); 2710 } 2711 2712 /* Add the current set of unused targets to our queue. */ 2713 delegpt_add_unused_targets(iq->dp); 2714 2715 if(qstate->env->auth_zones) { 2716 /* apply rpz triggers at query time */ 2717 struct dns_msg* forged_response = rpz_callback_from_iterator_module(qstate, iq); 2718 if(forged_response != NULL) { 2719 qstate->ext_state[id] = module_finished; 2720 qstate->return_rcode = LDNS_RCODE_NOERROR; 2721 qstate->return_msg = forged_response; 2722 iq->response = forged_response; 2723 next_state(iq, FINISHED_STATE); 2724 if(!iter_prepend(iq, qstate->return_msg, qstate->region)) { 2725 log_err("rpz: prepend rrsets: out of memory"); 2726 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2727 } 2728 return 0; 2729 } 2730 } 2731 2732 /* Select the next usable target, filtering out unsuitable targets. */ 2733 target = iter_server_selection(ie, qstate->env, iq->dp, 2734 iq->dp->name, iq->dp->namelen, iq->qchase.qtype, 2735 &iq->dnssec_lame_query, &iq->chase_to_rd, 2736 iq->num_target_queries, qstate->blacklist, 2737 qstate->prefetch_leeway); 2738 2739 /* If no usable target was selected... */ 2740 if(!target) { 2741 /* Here we distinguish between three states: generate a new 2742 * target query, just wait, or quit (with a SERVFAIL). 2743 * We have the following information: number of active 2744 * target queries, number of active current queries, 2745 * the presence of missing targets at this delegation 2746 * point, and the given query target policy. */ 2747 2748 /* Check for the wait condition. If this is true, then 2749 * an action must be taken. */ 2750 if(iq->num_target_queries==0 && iq->num_current_queries==0) { 2751 /* If there is nothing to wait for, then we need 2752 * to distinguish between generating (a) new target 2753 * query, or failing. */ 2754 if(delegpt_count_missing_targets(iq->dp, NULL) > 0) { 2755 int qs = 0; 2756 verbose(VERB_ALGO, "querying for next " 2757 "missing target"); 2758 if(!query_for_targets(qstate, iq, ie, id, 2759 1, &qs)) { 2760 errinf(qstate, "could not fetch nameserver"); 2761 errinf_dname(qstate, "at zone", iq->dp->name); 2762 return error_response(qstate, id, 2763 LDNS_RCODE_SERVFAIL); 2764 } 2765 if(qs == 0 && 2766 delegpt_count_missing_targets(iq->dp, NULL) == 0){ 2767 /* it looked like there were missing 2768 * targets, but they did not turn up. 2769 * Try the bad choices again (if any), 2770 * when we get back here missing==0, 2771 * so this is not a loop. */ 2772 return 1; 2773 } 2774 iq->num_target_queries += qs; 2775 target_count_increase(iq, qs); 2776 } 2777 /* Since a target query might have been made, we 2778 * need to check again. */ 2779 if(iq->num_target_queries == 0) { 2780 /* if in capsforid fallback, instead of last 2781 * resort, we agree with the current reply 2782 * we have (if any) (our count of addrs bad)*/ 2783 if(iq->caps_fallback && iq->caps_reply) { 2784 /* we're done, process the response */ 2785 verbose(VERB_ALGO, "0x20 fallback had %d responses, " 2786 "but no more servers except " 2787 "last resort, done.", 2788 (int)iq->caps_server+1); 2789 iq->response = iq->caps_response; 2790 iq->caps_fallback = 0; 2791 iter_dec_attempts(iq->dp, 3, ie->outbound_msg_retry); /* space for fallback */ 2792 iq->num_current_queries++; /* RespState decrements it*/ 2793 iq->referral_count++; /* make sure we don't loop */ 2794 iq->sent_count = 0; 2795 iq->dp_target_count = 0; 2796 iq->state = QUERY_RESP_STATE; 2797 return 1; 2798 } 2799 return processLastResort(qstate, iq, ie, id); 2800 } 2801 } 2802 2803 /* otherwise, we have no current targets, so submerge 2804 * until one of the target or direct queries return. */ 2805 verbose(VERB_ALGO, "no current targets"); 2806 check_waiting_queries(iq, qstate, id); 2807 /* undo qname minimise step because we'll get back here 2808 * to do it again */ 2809 if(qout_orig && iq->minimise_count > 0) { 2810 iq->minimise_count--; 2811 iq->qinfo_out.qname = qout_orig; 2812 iq->qinfo_out.qname_len = qout_orig_len; 2813 } 2814 return 0; 2815 } 2816 2817 /* We have a target. We could have created promiscuous target 2818 * queries but we are currently under pressure (mesh_jostle_exceeded). 2819 * If we are configured to allow promiscuous target queries and haven't 2820 * gone out to the network for a target query for this delegation, then 2821 * it is possible to slip in a promiscuous one with a 1/10 chance. */ 2822 if(can_do_promisc && tf_policy == 0 && iq->depth == 0 2823 && iq->depth < ie->max_dependency_depth 2824 && ie->target_fetch_policy[iq->depth] != 0 2825 && iq->dp_target_count == 0 2826 && !ub_random_max(qstate->env->rnd, 10)) { 2827 int extra = 0; 2828 verbose(VERB_ALGO, "available target exists in cache but " 2829 "attempt to get extra 1 target"); 2830 (void)query_for_targets(qstate, iq, ie, id, 1, &extra); 2831 /* errors ignored, these targets are not strictly necessary for 2832 * this result, we do not have to reply with SERVFAIL */ 2833 if(extra > 0) { 2834 iq->num_target_queries += extra; 2835 target_count_increase(iq, extra); 2836 check_waiting_queries(iq, qstate, id); 2837 /* undo qname minimise step because we'll get back here 2838 * to do it again */ 2839 if(qout_orig && iq->minimise_count > 0) { 2840 iq->minimise_count--; 2841 iq->qinfo_out.qname = qout_orig; 2842 iq->qinfo_out.qname_len = qout_orig_len; 2843 } 2844 return 0; 2845 } 2846 } 2847 2848 /* Do not check ratelimit for forwarding queries or if we already got a 2849 * pass. */ 2850 sq_check_ratelimit = (!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok); 2851 /* We have a valid target. */ 2852 if(verbosity >= VERB_QUERY) { 2853 log_query_info(VERB_QUERY, "sending query:", &iq->qinfo_out); 2854 log_name_addr(VERB_QUERY, "sending to target:", iq->dp->name, 2855 &target->addr, target->addrlen); 2856 verbose(VERB_ALGO, "dnssec status: %s%s", 2857 iq->dnssec_expected?"expected": "not expected", 2858 iq->dnssec_lame_query?" but lame_query anyway": ""); 2859 } 2860 2861 real_addr = target->addr; 2862 real_addrlen = target->addrlen; 2863 2864 if(ie->use_nat64 && target->addr.ss_family == AF_INET) { 2865 addr_to_nat64(&target->addr, &ie->nat64_prefix_addr, 2866 ie->nat64_prefix_addrlen, ie->nat64_prefix_net, 2867 &real_addr, &real_addrlen); 2868 log_name_addr(VERB_QUERY, "applied NAT64:", 2869 iq->dp->name, &real_addr, real_addrlen); 2870 } 2871 2872 fptr_ok(fptr_whitelist_modenv_send_query(qstate->env->send_query)); 2873 outq = (*qstate->env->send_query)(&iq->qinfo_out, 2874 iq->chase_flags | (iq->chase_to_rd?BIT_RD:0), 2875 /* unset CD if to forwarder(RD set) and not dnssec retry 2876 * (blacklist nonempty) and no trust-anchors are configured 2877 * above the qname or on the first attempt when dnssec is on */ 2878 EDNS_DO| ((iq->chase_to_rd||(iq->chase_flags&BIT_RD)!=0)&& 2879 !qstate->blacklist&&(!iter_qname_indicates_dnssec(qstate->env, 2880 &iq->qinfo_out)||target->attempts==1)?0:BIT_CD), 2881 iq->dnssec_expected, iq->caps_fallback || is_caps_whitelisted( 2882 ie, iq), sq_check_ratelimit, &real_addr, real_addrlen, 2883 iq->dp->name, iq->dp->namelen, 2884 (iq->dp->tcp_upstream || qstate->env->cfg->tcp_upstream), 2885 (iq->dp->ssl_upstream || qstate->env->cfg->ssl_upstream), 2886 target->tls_auth_name, qstate, &sq_was_ratelimited); 2887 if(!outq) { 2888 if(sq_was_ratelimited) { 2889 lock_basic_lock(&ie->queries_ratelimit_lock); 2890 ie->num_queries_ratelimited++; 2891 lock_basic_unlock(&ie->queries_ratelimit_lock); 2892 verbose(VERB_ALGO, "query exceeded ratelimits"); 2893 qstate->was_ratelimited = 1; 2894 errinf_dname(qstate, "exceeded ratelimit for zone", 2895 iq->dp->name); 2896 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 2897 } 2898 log_addr(VERB_QUERY, "error sending query to auth server", 2899 &real_addr, real_addrlen); 2900 if(qstate->env->cfg->qname_minimisation) 2901 iq->minimisation_state = SKIP_MINIMISE_STATE; 2902 return next_state(iq, QUERYTARGETS_STATE); 2903 } 2904 outbound_list_insert(&iq->outlist, outq); 2905 iq->num_current_queries++; 2906 iq->sent_count++; 2907 qstate->ext_state[id] = module_wait_reply; 2908 2909 return 0; 2910 } 2911 2912 /** find NS rrset in given list */ 2913 static struct ub_packed_rrset_key* 2914 find_NS(struct reply_info* rep, size_t from, size_t to) 2915 { 2916 size_t i; 2917 for(i=from; i<to; i++) { 2918 if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NS) 2919 return rep->rrsets[i]; 2920 } 2921 return NULL; 2922 } 2923 2924 2925 /** 2926 * Process the query response. All queries end up at this state first. This 2927 * process generally consists of analyzing the response and routing the 2928 * event to the next state (either bouncing it back to a request state, or 2929 * terminating the processing for this event). 2930 * 2931 * @param qstate: query state. 2932 * @param iq: iterator query state. 2933 * @param ie: iterator shared global environment. 2934 * @param id: module id. 2935 * @return true if the event requires more immediate processing, false if 2936 * not. This is generally only true when forwarding the request to 2937 * the final state (i.e., on answer). 2938 */ 2939 static int 2940 processQueryResponse(struct module_qstate* qstate, struct iter_qstate* iq, 2941 struct iter_env* ie, int id) 2942 { 2943 int dnsseclame = 0, origtypecname = 0; 2944 enum response_type type; 2945 2946 iq->num_current_queries--; 2947 2948 if(!inplace_cb_query_response_call(qstate->env, qstate, iq->response)) 2949 log_err("unable to call query_response callback"); 2950 2951 if(iq->response == NULL) { 2952 /* Don't increment qname when QNAME minimisation is enabled */ 2953 if(qstate->env->cfg->qname_minimisation) { 2954 iq->minimisation_state = SKIP_MINIMISE_STATE; 2955 } 2956 iq->timeout_count++; 2957 iq->chase_to_rd = 0; 2958 iq->dnssec_lame_query = 0; 2959 verbose(VERB_ALGO, "query response was timeout"); 2960 return next_state(iq, QUERYTARGETS_STATE); 2961 } 2962 iq->timeout_count = 0; 2963 type = response_type_from_server( 2964 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd), 2965 iq->response, &iq->qinfo_out, iq->dp); 2966 iq->chase_to_rd = 0; 2967 /* remove TC flag, if this is erroneously set by TCP upstream */ 2968 iq->response->rep->flags &= ~BIT_TC; 2969 if(type == RESPONSE_TYPE_REFERRAL && (iq->chase_flags&BIT_RD) && 2970 !iq->auth_zone_response) { 2971 /* When forwarding (RD bit is set), we handle referrals 2972 * differently. No queries should be sent elsewhere */ 2973 type = RESPONSE_TYPE_ANSWER; 2974 } 2975 if(!qstate->env->cfg->disable_dnssec_lame_check && iq->dnssec_expected 2976 && !iq->dnssec_lame_query && 2977 !(iq->chase_flags&BIT_RD) 2978 && iq->sent_count < DNSSEC_LAME_DETECT_COUNT 2979 && type != RESPONSE_TYPE_LAME 2980 && type != RESPONSE_TYPE_REC_LAME 2981 && type != RESPONSE_TYPE_THROWAWAY 2982 && type != RESPONSE_TYPE_UNTYPED) { 2983 /* a possible answer, see if it is missing DNSSEC */ 2984 /* but not when forwarding, so we dont mark fwder lame */ 2985 if(!iter_msg_has_dnssec(iq->response)) { 2986 /* Mark this address as dnsseclame in this dp, 2987 * because that will make serverselection disprefer 2988 * it, but also, once it is the only final option, 2989 * use dnssec-lame-bypass if it needs to query there.*/ 2990 if(qstate->reply) { 2991 struct delegpt_addr* a = delegpt_find_addr( 2992 iq->dp, &qstate->reply->remote_addr, 2993 qstate->reply->remote_addrlen); 2994 if(a) a->dnsseclame = 1; 2995 } 2996 /* test the answer is from the zone we expected, 2997 * otherwise, (due to parent,child on same server), we 2998 * might mark the server,zone lame inappropriately */ 2999 if(!iter_msg_from_zone(iq->response, iq->dp, type, 3000 iq->qchase.qclass)) 3001 qstate->reply = NULL; 3002 type = RESPONSE_TYPE_LAME; 3003 dnsseclame = 1; 3004 } 3005 } else iq->dnssec_lame_query = 0; 3006 /* see if referral brings us close to the target */ 3007 if(type == RESPONSE_TYPE_REFERRAL) { 3008 struct ub_packed_rrset_key* ns = find_NS( 3009 iq->response->rep, iq->response->rep->an_numrrsets, 3010 iq->response->rep->an_numrrsets 3011 + iq->response->rep->ns_numrrsets); 3012 if(!ns) ns = find_NS(iq->response->rep, 0, 3013 iq->response->rep->an_numrrsets); 3014 if(!ns || !dname_strict_subdomain_c(ns->rk.dname, iq->dp->name) 3015 || !dname_subdomain_c(iq->qchase.qname, ns->rk.dname)){ 3016 verbose(VERB_ALGO, "bad referral, throwaway"); 3017 type = RESPONSE_TYPE_THROWAWAY; 3018 } else 3019 iter_scrub_ds(iq->response, ns, iq->dp->name); 3020 } else iter_scrub_ds(iq->response, NULL, NULL); 3021 if(type == RESPONSE_TYPE_THROWAWAY && 3022 FLAGS_GET_RCODE(iq->response->rep->flags) == LDNS_RCODE_YXDOMAIN) { 3023 /* YXDOMAIN is a permanent error, no need to retry */ 3024 type = RESPONSE_TYPE_ANSWER; 3025 } 3026 if(type == RESPONSE_TYPE_CNAME) 3027 origtypecname = 1; 3028 if(type == RESPONSE_TYPE_CNAME && iq->response->rep->an_numrrsets >= 1 3029 && ntohs(iq->response->rep->rrsets[0]->rk.type) == LDNS_RR_TYPE_DNAME) { 3030 uint8_t* sname = NULL; 3031 size_t snamelen = 0; 3032 get_cname_target(iq->response->rep->rrsets[0], &sname, 3033 &snamelen); 3034 if(snamelen && dname_subdomain_c(sname, iq->response->rep->rrsets[0]->rk.dname)) { 3035 /* DNAME to a subdomain loop; do not recurse */ 3036 type = RESPONSE_TYPE_ANSWER; 3037 } 3038 } else if(type == RESPONSE_TYPE_CNAME && 3039 iq->qchase.qtype == LDNS_RR_TYPE_CNAME && 3040 iq->minimisation_state == MINIMISE_STATE && 3041 query_dname_compare(iq->qchase.qname, iq->qinfo_out.qname) == 0) { 3042 /* The minimised query for full QTYPE and hidden QTYPE can be 3043 * classified as CNAME response type, even when the original 3044 * QTYPE=CNAME. This should be treated as answer response type. 3045 */ 3046 type = RESPONSE_TYPE_ANSWER; 3047 } 3048 3049 /* handle each of the type cases */ 3050 if(type == RESPONSE_TYPE_ANSWER) { 3051 /* ANSWER type responses terminate the query algorithm, 3052 * so they sent on their */ 3053 if(verbosity >= VERB_DETAIL) { 3054 verbose(VERB_DETAIL, "query response was %s", 3055 FLAGS_GET_RCODE(iq->response->rep->flags) 3056 ==LDNS_RCODE_NXDOMAIN?"NXDOMAIN ANSWER": 3057 (iq->response->rep->an_numrrsets?"ANSWER": 3058 "nodata ANSWER")); 3059 } 3060 /* if qtype is DS, check we have the right level of answer, 3061 * like grandchild answer but we need the middle, reject it */ 3062 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point 3063 && !(iq->chase_flags&BIT_RD) 3064 && iter_ds_toolow(iq->response, iq->dp) 3065 && iter_dp_cangodown(&iq->qchase, iq->dp)) { 3066 /* close down outstanding requests to be discarded */ 3067 outbound_list_clear(&iq->outlist); 3068 iq->num_current_queries = 0; 3069 fptr_ok(fptr_whitelist_modenv_detach_subs( 3070 qstate->env->detach_subs)); 3071 (*qstate->env->detach_subs)(qstate); 3072 iq->num_target_queries = 0; 3073 return processDSNSFind(qstate, iq, id); 3074 } 3075 if(!qstate->no_cache_store) 3076 iter_dns_store(qstate->env, &iq->response->qinfo, 3077 iq->response->rep, 3078 iq->qchase.qtype != iq->response->qinfo.qtype, 3079 qstate->prefetch_leeway, 3080 iq->dp&&iq->dp->has_parent_side_NS, 3081 qstate->region, qstate->query_flags, 3082 qstate->qstarttime); 3083 /* close down outstanding requests to be discarded */ 3084 outbound_list_clear(&iq->outlist); 3085 iq->num_current_queries = 0; 3086 fptr_ok(fptr_whitelist_modenv_detach_subs( 3087 qstate->env->detach_subs)); 3088 (*qstate->env->detach_subs)(qstate); 3089 iq->num_target_queries = 0; 3090 if(qstate->reply) 3091 sock_list_insert(&qstate->reply_origin, 3092 &qstate->reply->remote_addr, 3093 qstate->reply->remote_addrlen, qstate->region); 3094 if(iq->minimisation_state != DONOT_MINIMISE_STATE 3095 && !(iq->chase_flags & BIT_RD)) { 3096 if(FLAGS_GET_RCODE(iq->response->rep->flags) != 3097 LDNS_RCODE_NOERROR) { 3098 if(qstate->env->cfg->qname_minimisation_strict) { 3099 if(FLAGS_GET_RCODE(iq->response->rep->flags) == 3100 LDNS_RCODE_NXDOMAIN) { 3101 iter_scrub_nxdomain(iq->response); 3102 return final_state(iq); 3103 } 3104 return error_response(qstate, id, 3105 LDNS_RCODE_SERVFAIL); 3106 } 3107 /* Best effort qname-minimisation. 3108 * Stop minimising and send full query when 3109 * RCODE is not NOERROR. */ 3110 iq->minimisation_state = DONOT_MINIMISE_STATE; 3111 } 3112 if(FLAGS_GET_RCODE(iq->response->rep->flags) == 3113 LDNS_RCODE_NXDOMAIN && !origtypecname) { 3114 /* Stop resolving when NXDOMAIN is DNSSEC 3115 * signed. Based on assumption that nameservers 3116 * serving signed zones do not return NXDOMAIN 3117 * for empty-non-terminals. */ 3118 /* If this response is actually a CNAME type, 3119 * the nxdomain rcode may not be for the qname, 3120 * and so it is not the final response. */ 3121 if(iq->dnssec_expected) 3122 return final_state(iq); 3123 /* Make subrequest to validate intermediate 3124 * NXDOMAIN if harden-below-nxdomain is 3125 * enabled. */ 3126 if(qstate->env->cfg->harden_below_nxdomain && 3127 qstate->env->need_to_validate) { 3128 struct module_qstate* subq = NULL; 3129 log_query_info(VERB_QUERY, 3130 "schedule NXDOMAIN validation:", 3131 &iq->response->qinfo); 3132 if(!generate_sub_request( 3133 iq->response->qinfo.qname, 3134 iq->response->qinfo.qname_len, 3135 iq->response->qinfo.qtype, 3136 iq->response->qinfo.qclass, 3137 qstate, id, iq, 3138 INIT_REQUEST_STATE, 3139 FINISHED_STATE, &subq, 1, 1)) 3140 verbose(VERB_ALGO, 3141 "could not validate NXDOMAIN " 3142 "response"); 3143 } 3144 } 3145 return next_state(iq, QUERYTARGETS_STATE); 3146 } 3147 return final_state(iq); 3148 } else if(type == RESPONSE_TYPE_REFERRAL) { 3149 /* REFERRAL type responses get a reset of the 3150 * delegation point, and back to the QUERYTARGETS_STATE. */ 3151 verbose(VERB_DETAIL, "query response was REFERRAL"); 3152 3153 /* if hardened, only store referral if we asked for it */ 3154 if(!qstate->no_cache_store && 3155 (!qstate->env->cfg->harden_referral_path || 3156 ( qstate->qinfo.qtype == LDNS_RR_TYPE_NS 3157 && (qstate->query_flags&BIT_RD) 3158 && !(qstate->query_flags&BIT_CD) 3159 /* we know that all other NS rrsets are scrubbed 3160 * away, thus on referral only one is left. 3161 * see if that equals the query name... */ 3162 && ( /* auth section, but sometimes in answer section*/ 3163 reply_find_rrset_section_ns(iq->response->rep, 3164 iq->qchase.qname, iq->qchase.qname_len, 3165 LDNS_RR_TYPE_NS, iq->qchase.qclass) 3166 || reply_find_rrset_section_an(iq->response->rep, 3167 iq->qchase.qname, iq->qchase.qname_len, 3168 LDNS_RR_TYPE_NS, iq->qchase.qclass) 3169 ) 3170 ))) { 3171 /* Store the referral under the current query */ 3172 /* no prefetch-leeway, since its not the answer */ 3173 iter_dns_store(qstate->env, &iq->response->qinfo, 3174 iq->response->rep, 1, 0, 0, NULL, 0, 3175 qstate->qstarttime); 3176 if(iq->store_parent_NS) 3177 iter_store_parentside_NS(qstate->env, 3178 iq->response->rep); 3179 if(qstate->env->neg_cache) 3180 val_neg_addreferral(qstate->env->neg_cache, 3181 iq->response->rep, iq->dp->name); 3182 } 3183 /* store parent-side-in-zone-glue, if directly queried for */ 3184 if(!qstate->no_cache_store && iq->query_for_pside_glue 3185 && !iq->pside_glue) { 3186 iq->pside_glue = reply_find_rrset(iq->response->rep, 3187 iq->qchase.qname, iq->qchase.qname_len, 3188 iq->qchase.qtype, iq->qchase.qclass); 3189 if(iq->pside_glue) { 3190 log_rrset_key(VERB_ALGO, "found parent-side " 3191 "glue", iq->pside_glue); 3192 iter_store_parentside_rrset(qstate->env, 3193 iq->pside_glue); 3194 } 3195 } 3196 3197 /* Reset the event state, setting the current delegation 3198 * point to the referral. */ 3199 iq->deleg_msg = iq->response; 3200 iq->dp = delegpt_from_message(iq->response, qstate->region); 3201 if (qstate->env->cfg->qname_minimisation) 3202 iq->minimisation_state = INIT_MINIMISE_STATE; 3203 if(!iq->dp) { 3204 errinf(qstate, "malloc failure, for delegation point"); 3205 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 3206 } 3207 if(!cache_fill_missing(qstate->env, iq->qchase.qclass, 3208 qstate->region, iq->dp)) { 3209 errinf(qstate, "malloc failure, copy extra info into delegation point"); 3210 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 3211 } 3212 if(iq->store_parent_NS && query_dname_compare(iq->dp->name, 3213 iq->store_parent_NS->name) == 0) 3214 iter_merge_retry_counts(iq->dp, iq->store_parent_NS, 3215 ie->outbound_msg_retry); 3216 delegpt_log(VERB_ALGO, iq->dp); 3217 /* Count this as a referral. */ 3218 iq->referral_count++; 3219 iq->sent_count = 0; 3220 iq->dp_target_count = 0; 3221 /* see if the next dp is a trust anchor, or a DS was sent 3222 * along, indicating dnssec is expected for next zone */ 3223 iq->dnssec_expected = iter_indicates_dnssec(qstate->env, 3224 iq->dp, iq->response, iq->qchase.qclass); 3225 /* if dnssec, validating then also fetch the key for the DS */ 3226 if(iq->dnssec_expected && qstate->env->cfg->prefetch_key && 3227 !(qstate->query_flags&BIT_CD)) 3228 generate_dnskey_prefetch(qstate, iq, id); 3229 3230 /* spawn off NS and addr to auth servers for the NS we just 3231 * got in the referral. This gets authoritative answer 3232 * (answer section trust level) rrset. 3233 * right after, we detach the subs, answer goes to cache. */ 3234 if(qstate->env->cfg->harden_referral_path) 3235 generate_ns_check(qstate, iq, id); 3236 3237 /* stop current outstanding queries. 3238 * FIXME: should the outstanding queries be waited for and 3239 * handled? Say by a subquery that inherits the outbound_entry. 3240 */ 3241 outbound_list_clear(&iq->outlist); 3242 iq->num_current_queries = 0; 3243 fptr_ok(fptr_whitelist_modenv_detach_subs( 3244 qstate->env->detach_subs)); 3245 (*qstate->env->detach_subs)(qstate); 3246 iq->num_target_queries = 0; 3247 iq->response = NULL; 3248 iq->fail_addr_type = 0; 3249 verbose(VERB_ALGO, "cleared outbound list for next round"); 3250 return next_state(iq, QUERYTARGETS_STATE); 3251 } else if(type == RESPONSE_TYPE_CNAME) { 3252 uint8_t* sname = NULL; 3253 size_t snamelen = 0; 3254 /* CNAME type responses get a query restart (i.e., get a 3255 * reset of the query state and go back to INIT_REQUEST_STATE). 3256 */ 3257 verbose(VERB_DETAIL, "query response was CNAME"); 3258 if(verbosity >= VERB_ALGO) 3259 log_dns_msg("cname msg", &iq->response->qinfo, 3260 iq->response->rep); 3261 /* if qtype is DS, check we have the right level of answer, 3262 * like grandchild answer but we need the middle, reject it */ 3263 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point 3264 && !(iq->chase_flags&BIT_RD) 3265 && iter_ds_toolow(iq->response, iq->dp) 3266 && iter_dp_cangodown(&iq->qchase, iq->dp)) { 3267 outbound_list_clear(&iq->outlist); 3268 iq->num_current_queries = 0; 3269 fptr_ok(fptr_whitelist_modenv_detach_subs( 3270 qstate->env->detach_subs)); 3271 (*qstate->env->detach_subs)(qstate); 3272 iq->num_target_queries = 0; 3273 return processDSNSFind(qstate, iq, id); 3274 } 3275 /* Process the CNAME response. */ 3276 if(!handle_cname_response(qstate, iq, iq->response, 3277 &sname, &snamelen)) { 3278 errinf(qstate, "malloc failure, CNAME info"); 3279 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 3280 } 3281 /* cache the CNAME response under the current query */ 3282 /* NOTE : set referral=1, so that rrsets get stored but not 3283 * the partial query answer (CNAME only). */ 3284 /* prefetchleeway applied because this updates answer parts */ 3285 if(!qstate->no_cache_store) 3286 iter_dns_store(qstate->env, &iq->response->qinfo, 3287 iq->response->rep, 1, qstate->prefetch_leeway, 3288 iq->dp&&iq->dp->has_parent_side_NS, NULL, 3289 qstate->query_flags, qstate->qstarttime); 3290 /* set the current request's qname to the new value. */ 3291 iq->qchase.qname = sname; 3292 iq->qchase.qname_len = snamelen; 3293 if(qstate->env->auth_zones) { 3294 /* apply rpz qname triggers after cname */ 3295 struct dns_msg* forged_response = 3296 rpz_callback_from_iterator_cname(qstate, iq); 3297 while(forged_response && reply_find_rrset_section_an( 3298 forged_response->rep, iq->qchase.qname, 3299 iq->qchase.qname_len, LDNS_RR_TYPE_CNAME, 3300 iq->qchase.qclass)) { 3301 /* another cname to follow */ 3302 if(!handle_cname_response(qstate, iq, forged_response, 3303 &sname, &snamelen)) { 3304 errinf(qstate, "malloc failure, CNAME info"); 3305 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 3306 } 3307 iq->qchase.qname = sname; 3308 iq->qchase.qname_len = snamelen; 3309 forged_response = 3310 rpz_callback_from_iterator_cname(qstate, iq); 3311 } 3312 if(forged_response != NULL) { 3313 qstate->ext_state[id] = module_finished; 3314 qstate->return_rcode = LDNS_RCODE_NOERROR; 3315 qstate->return_msg = forged_response; 3316 iq->response = forged_response; 3317 next_state(iq, FINISHED_STATE); 3318 if(!iter_prepend(iq, qstate->return_msg, qstate->region)) { 3319 log_err("rpz: after cname, prepend rrsets: out of memory"); 3320 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 3321 } 3322 qstate->return_msg->qinfo = qstate->qinfo; 3323 return 0; 3324 } 3325 } 3326 /* Clear the query state, since this is a query restart. */ 3327 iq->deleg_msg = NULL; 3328 iq->dp = NULL; 3329 iq->dsns_point = NULL; 3330 iq->auth_zone_response = 0; 3331 iq->sent_count = 0; 3332 iq->dp_target_count = 0; 3333 if(iq->minimisation_state != MINIMISE_STATE) 3334 /* Only count as query restart when it is not an extra 3335 * query as result of qname minimisation. */ 3336 iq->query_restart_count++; 3337 if(qstate->env->cfg->qname_minimisation) 3338 iq->minimisation_state = INIT_MINIMISE_STATE; 3339 3340 /* stop current outstanding queries. 3341 * FIXME: should the outstanding queries be waited for and 3342 * handled? Say by a subquery that inherits the outbound_entry. 3343 */ 3344 outbound_list_clear(&iq->outlist); 3345 iq->num_current_queries = 0; 3346 fptr_ok(fptr_whitelist_modenv_detach_subs( 3347 qstate->env->detach_subs)); 3348 (*qstate->env->detach_subs)(qstate); 3349 iq->num_target_queries = 0; 3350 if(qstate->reply) 3351 sock_list_insert(&qstate->reply_origin, 3352 &qstate->reply->remote_addr, 3353 qstate->reply->remote_addrlen, qstate->region); 3354 verbose(VERB_ALGO, "cleared outbound list for query restart"); 3355 /* go to INIT_REQUEST_STATE for new qname. */ 3356 return next_state(iq, INIT_REQUEST_STATE); 3357 } else if(type == RESPONSE_TYPE_LAME) { 3358 /* Cache the LAMEness. */ 3359 verbose(VERB_DETAIL, "query response was %sLAME", 3360 dnsseclame?"DNSSEC ":""); 3361 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) { 3362 log_err("mark lame: mismatch in qname and dpname"); 3363 /* throwaway this reply below */ 3364 } else if(qstate->reply) { 3365 /* need addr for lameness cache, but we may have 3366 * gotten this from cache, so test to be sure */ 3367 if(!infra_set_lame(qstate->env->infra_cache, 3368 &qstate->reply->remote_addr, 3369 qstate->reply->remote_addrlen, 3370 iq->dp->name, iq->dp->namelen, 3371 *qstate->env->now, dnsseclame, 0, 3372 iq->qchase.qtype)) 3373 log_err("mark host lame: out of memory"); 3374 } 3375 } else if(type == RESPONSE_TYPE_REC_LAME) { 3376 /* Cache the LAMEness. */ 3377 verbose(VERB_DETAIL, "query response REC_LAME: " 3378 "recursive but not authoritative server"); 3379 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) { 3380 log_err("mark rec_lame: mismatch in qname and dpname"); 3381 /* throwaway this reply below */ 3382 } else if(qstate->reply) { 3383 /* need addr for lameness cache, but we may have 3384 * gotten this from cache, so test to be sure */ 3385 verbose(VERB_DETAIL, "mark as REC_LAME"); 3386 if(!infra_set_lame(qstate->env->infra_cache, 3387 &qstate->reply->remote_addr, 3388 qstate->reply->remote_addrlen, 3389 iq->dp->name, iq->dp->namelen, 3390 *qstate->env->now, 0, 1, iq->qchase.qtype)) 3391 log_err("mark host lame: out of memory"); 3392 } 3393 } else if(type == RESPONSE_TYPE_THROWAWAY) { 3394 /* LAME and THROWAWAY responses are handled the same way. 3395 * In this case, the event is just sent directly back to 3396 * the QUERYTARGETS_STATE without resetting anything, 3397 * because, clearly, the next target must be tried. */ 3398 verbose(VERB_DETAIL, "query response was THROWAWAY"); 3399 } else { 3400 log_warn("A query response came back with an unknown type: %d", 3401 (int)type); 3402 } 3403 3404 /* LAME, THROWAWAY and "unknown" all end up here. 3405 * Recycle to the QUERYTARGETS state to hopefully try a 3406 * different target. */ 3407 if (qstate->env->cfg->qname_minimisation && 3408 !qstate->env->cfg->qname_minimisation_strict) 3409 iq->minimisation_state = DONOT_MINIMISE_STATE; 3410 if(iq->auth_zone_response) { 3411 /* can we fallback? */ 3412 iq->auth_zone_response = 0; 3413 if(!auth_zones_can_fallback(qstate->env->auth_zones, 3414 iq->dp->name, iq->dp->namelen, qstate->qinfo.qclass)) { 3415 verbose(VERB_ALGO, "auth zone response bad, and no" 3416 " fallback possible, servfail"); 3417 errinf_dname(qstate, "response is bad, no fallback, " 3418 "for auth zone", iq->dp->name); 3419 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 3420 } 3421 verbose(VERB_ALGO, "auth zone response was bad, " 3422 "fallback enabled"); 3423 iq->auth_zone_avoid = 1; 3424 if(iq->dp->auth_dp) { 3425 /* we are using a dp for the auth zone, with no 3426 * nameservers, get one first */ 3427 iq->dp = NULL; 3428 return next_state(iq, INIT_REQUEST_STATE); 3429 } 3430 } 3431 return next_state(iq, QUERYTARGETS_STATE); 3432 } 3433 3434 /** 3435 * Return priming query results to interested super querystates. 3436 * 3437 * Sets the delegation point and delegation message (not nonRD queries). 3438 * This is a callback from walk_supers. 3439 * 3440 * @param qstate: priming query state that finished. 3441 * @param id: module id. 3442 * @param forq: the qstate for which priming has been done. 3443 */ 3444 static void 3445 prime_supers(struct module_qstate* qstate, int id, struct module_qstate* forq) 3446 { 3447 struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id]; 3448 struct delegpt* dp = NULL; 3449 3450 log_assert(qstate->is_priming || foriq->wait_priming_stub); 3451 log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR); 3452 /* Convert our response to a delegation point */ 3453 dp = delegpt_from_message(qstate->return_msg, forq->region); 3454 if(!dp) { 3455 /* if there is no convertible delegation point, then 3456 * the ANSWER type was (presumably) a negative answer. */ 3457 verbose(VERB_ALGO, "prime response was not a positive " 3458 "ANSWER; failing"); 3459 foriq->dp = NULL; 3460 foriq->state = QUERYTARGETS_STATE; 3461 return; 3462 } 3463 3464 log_query_info(VERB_DETAIL, "priming successful for", &qstate->qinfo); 3465 delegpt_log(VERB_ALGO, dp); 3466 foriq->dp = dp; 3467 foriq->deleg_msg = dns_copy_msg(qstate->return_msg, forq->region); 3468 if(!foriq->deleg_msg) { 3469 log_err("copy prime response: out of memory"); 3470 foriq->dp = NULL; 3471 foriq->state = QUERYTARGETS_STATE; 3472 return; 3473 } 3474 3475 /* root priming responses go to init stage 2, priming stub 3476 * responses to to stage 3. */ 3477 if(foriq->wait_priming_stub) { 3478 foriq->state = INIT_REQUEST_3_STATE; 3479 foriq->wait_priming_stub = 0; 3480 } else foriq->state = INIT_REQUEST_2_STATE; 3481 /* because we are finished, the parent will be reactivated */ 3482 } 3483 3484 /** 3485 * This handles the response to a priming query. This is used to handle both 3486 * root and stub priming responses. This is basically the equivalent of the 3487 * QUERY_RESP_STATE, but will not handle CNAME responses and will treat 3488 * REFERRALs as ANSWERS. It will also update and reactivate the originating 3489 * event. 3490 * 3491 * @param qstate: query state. 3492 * @param id: module id. 3493 * @return true if the event needs more immediate processing, false if not. 3494 * This state always returns false. 3495 */ 3496 static int 3497 processPrimeResponse(struct module_qstate* qstate, int id) 3498 { 3499 struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id]; 3500 enum response_type type; 3501 iq->response->rep->flags &= ~(BIT_RD|BIT_RA); /* ignore rec-lame */ 3502 type = response_type_from_server( 3503 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd), 3504 iq->response, &iq->qchase, iq->dp); 3505 if(type == RESPONSE_TYPE_ANSWER) { 3506 qstate->return_rcode = LDNS_RCODE_NOERROR; 3507 qstate->return_msg = iq->response; 3508 } else { 3509 errinf(qstate, "prime response did not get an answer"); 3510 errinf_dname(qstate, "for", qstate->qinfo.qname); 3511 qstate->return_rcode = LDNS_RCODE_SERVFAIL; 3512 qstate->return_msg = NULL; 3513 } 3514 3515 /* validate the root or stub after priming (if enabled). 3516 * This is the same query as the prime query, but with validation. 3517 * Now that we are primed, the additional queries that validation 3518 * may need can be resolved. */ 3519 if(qstate->env->cfg->harden_referral_path) { 3520 struct module_qstate* subq = NULL; 3521 log_nametypeclass(VERB_ALGO, "schedule prime validation", 3522 qstate->qinfo.qname, qstate->qinfo.qtype, 3523 qstate->qinfo.qclass); 3524 if(!generate_sub_request(qstate->qinfo.qname, 3525 qstate->qinfo.qname_len, qstate->qinfo.qtype, 3526 qstate->qinfo.qclass, qstate, id, iq, 3527 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1, 0)) { 3528 verbose(VERB_ALGO, "could not generate prime check"); 3529 } 3530 generate_a_aaaa_check(qstate, iq, id); 3531 } 3532 3533 /* This event is finished. */ 3534 qstate->ext_state[id] = module_finished; 3535 return 0; 3536 } 3537 3538 /** 3539 * Do final processing on responses to target queries. Events reach this 3540 * state after the iterative resolution algorithm terminates. This state is 3541 * responsible for reactivating the original event, and housekeeping related 3542 * to received target responses (caching, updating the current delegation 3543 * point, etc). 3544 * Callback from walk_supers for every super state that is interested in 3545 * the results from this query. 3546 * 3547 * @param qstate: query state. 3548 * @param id: module id. 3549 * @param forq: super query state. 3550 */ 3551 static void 3552 processTargetResponse(struct module_qstate* qstate, int id, 3553 struct module_qstate* forq) 3554 { 3555 struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id]; 3556 struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id]; 3557 struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id]; 3558 struct ub_packed_rrset_key* rrset; 3559 struct delegpt_ns* dpns; 3560 log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR); 3561 3562 foriq->state = QUERYTARGETS_STATE; 3563 log_query_info(VERB_ALGO, "processTargetResponse", &qstate->qinfo); 3564 log_query_info(VERB_ALGO, "processTargetResponse super", &forq->qinfo); 3565 3566 /* Tell the originating event that this target query has finished 3567 * (regardless if it succeeded or not). */ 3568 foriq->num_target_queries--; 3569 3570 /* check to see if parent event is still interested (in orig name). */ 3571 if(!foriq->dp) { 3572 verbose(VERB_ALGO, "subq: parent not interested, was reset"); 3573 return; /* not interested anymore */ 3574 } 3575 dpns = delegpt_find_ns(foriq->dp, qstate->qinfo.qname, 3576 qstate->qinfo.qname_len); 3577 if(!dpns) { 3578 /* If not interested, just stop processing this event */ 3579 verbose(VERB_ALGO, "subq: parent not interested anymore"); 3580 /* could be because parent was jostled out of the cache, 3581 and a new identical query arrived, that does not want it*/ 3582 return; 3583 } 3584 3585 /* if iq->query_for_pside_glue then add the pside_glue (marked lame) */ 3586 if(iq->pside_glue) { 3587 /* if the pside_glue is NULL, then it could not be found, 3588 * the done_pside is already set when created and a cache 3589 * entry created in processFinished so nothing to do here */ 3590 log_rrset_key(VERB_ALGO, "add parentside glue to dp", 3591 iq->pside_glue); 3592 if(!delegpt_add_rrset(foriq->dp, forq->region, 3593 iq->pside_glue, 1, NULL)) 3594 log_err("out of memory adding pside glue"); 3595 } 3596 3597 /* This response is relevant to the current query, so we 3598 * add (attempt to add, anyway) this target(s) and reactivate 3599 * the original event. 3600 * NOTE: we could only look for the AnswerRRset if the 3601 * response type was ANSWER. */ 3602 rrset = reply_find_answer_rrset(&iq->qchase, qstate->return_msg->rep); 3603 if(rrset) { 3604 int additions = 0; 3605 /* if CNAMEs have been followed - add new NS to delegpt. */ 3606 /* BTW. RFC 1918 says NS should not have got CNAMEs. Robust. */ 3607 if(!delegpt_find_ns(foriq->dp, rrset->rk.dname, 3608 rrset->rk.dname_len)) { 3609 /* if dpns->lame then set newcname ns lame too */ 3610 if(!delegpt_add_ns(foriq->dp, forq->region, 3611 rrset->rk.dname, dpns->lame, dpns->tls_auth_name, 3612 dpns->port)) 3613 log_err("out of memory adding cnamed-ns"); 3614 } 3615 /* if dpns->lame then set the address(es) lame too */ 3616 if(!delegpt_add_rrset(foriq->dp, forq->region, rrset, 3617 dpns->lame, &additions)) 3618 log_err("out of memory adding targets"); 3619 if(!additions) { 3620 /* no new addresses, increase the nxns counter, like 3621 * this could be a list of wildcards with no new 3622 * addresses */ 3623 target_count_increase_nx(foriq, 1); 3624 } 3625 verbose(VERB_ALGO, "added target response"); 3626 delegpt_log(VERB_ALGO, foriq->dp); 3627 } else { 3628 verbose(VERB_ALGO, "iterator TargetResponse failed"); 3629 delegpt_mark_neg(dpns, qstate->qinfo.qtype); 3630 if((dpns->got4 == 2 || (!ie->supports_ipv4 && !ie->use_nat64)) && 3631 (dpns->got6 == 2 || !ie->supports_ipv6)) { 3632 dpns->resolved = 1; /* fail the target */ 3633 /* do not count cached answers */ 3634 if(qstate->reply_origin && qstate->reply_origin->len != 0) { 3635 target_count_increase_nx(foriq, 1); 3636 } 3637 } 3638 } 3639 } 3640 3641 /** 3642 * Process response for DS NS Find queries, that attempt to find the delegation 3643 * point where we ask the DS query from. 3644 * 3645 * @param qstate: query state. 3646 * @param id: module id. 3647 * @param forq: super query state. 3648 */ 3649 static void 3650 processDSNSResponse(struct module_qstate* qstate, int id, 3651 struct module_qstate* forq) 3652 { 3653 struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id]; 3654 3655 /* if the finished (iq->response) query has no NS set: continue 3656 * up to look for the right dp; nothing to change, do DPNSstate */ 3657 if(qstate->return_rcode != LDNS_RCODE_NOERROR) 3658 return; /* seek further */ 3659 /* find the NS RRset (without allowing CNAMEs) */ 3660 if(!reply_find_rrset(qstate->return_msg->rep, qstate->qinfo.qname, 3661 qstate->qinfo.qname_len, LDNS_RR_TYPE_NS, 3662 qstate->qinfo.qclass)){ 3663 return; /* seek further */ 3664 } 3665 3666 /* else, store as DP and continue at querytargets */ 3667 foriq->state = QUERYTARGETS_STATE; 3668 foriq->dp = delegpt_from_message(qstate->return_msg, forq->region); 3669 if(!foriq->dp) { 3670 log_err("out of memory in dsns dp alloc"); 3671 errinf(qstate, "malloc failure, in DS search"); 3672 return; /* dp==NULL in QUERYTARGETS makes SERVFAIL */ 3673 } 3674 /* success, go query the querytargets in the new dp (and go down) */ 3675 } 3676 3677 /** 3678 * Process response for qclass=ANY queries for a particular class. 3679 * Append to result or error-exit. 3680 * 3681 * @param qstate: query state. 3682 * @param id: module id. 3683 * @param forq: super query state. 3684 */ 3685 static void 3686 processClassResponse(struct module_qstate* qstate, int id, 3687 struct module_qstate* forq) 3688 { 3689 struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id]; 3690 struct dns_msg* from = qstate->return_msg; 3691 log_query_info(VERB_ALGO, "processClassResponse", &qstate->qinfo); 3692 log_query_info(VERB_ALGO, "processClassResponse super", &forq->qinfo); 3693 if(qstate->return_rcode != LDNS_RCODE_NOERROR) { 3694 /* cause servfail for qclass ANY query */ 3695 foriq->response = NULL; 3696 foriq->state = FINISHED_STATE; 3697 return; 3698 } 3699 /* append result */ 3700 if(!foriq->response) { 3701 /* allocate the response: copy RCODE, sec_state */ 3702 foriq->response = dns_copy_msg(from, forq->region); 3703 if(!foriq->response) { 3704 log_err("malloc failed for qclass ANY response"); 3705 foriq->state = FINISHED_STATE; 3706 return; 3707 } 3708 foriq->response->qinfo.qclass = forq->qinfo.qclass; 3709 /* qclass ANY does not receive the AA flag on replies */ 3710 foriq->response->rep->authoritative = 0; 3711 } else { 3712 struct dns_msg* to = foriq->response; 3713 /* add _from_ this response _to_ existing collection */ 3714 /* if there are records, copy RCODE */ 3715 /* lower sec_state if this message is lower */ 3716 if(from->rep->rrset_count != 0) { 3717 size_t n = from->rep->rrset_count+to->rep->rrset_count; 3718 struct ub_packed_rrset_key** dest, **d; 3719 /* copy appropriate rcode */ 3720 to->rep->flags = from->rep->flags; 3721 /* copy rrsets */ 3722 if(from->rep->rrset_count > RR_COUNT_MAX || 3723 to->rep->rrset_count > RR_COUNT_MAX) { 3724 log_err("malloc failed (too many rrsets) in collect ANY"); 3725 foriq->state = FINISHED_STATE; 3726 return; /* integer overflow protection */ 3727 } 3728 dest = regional_alloc(forq->region, sizeof(dest[0])*n); 3729 if(!dest) { 3730 log_err("malloc failed in collect ANY"); 3731 foriq->state = FINISHED_STATE; 3732 return; 3733 } 3734 d = dest; 3735 /* copy AN */ 3736 memcpy(dest, to->rep->rrsets, to->rep->an_numrrsets 3737 * sizeof(dest[0])); 3738 dest += to->rep->an_numrrsets; 3739 memcpy(dest, from->rep->rrsets, from->rep->an_numrrsets 3740 * sizeof(dest[0])); 3741 dest += from->rep->an_numrrsets; 3742 /* copy NS */ 3743 memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets, 3744 to->rep->ns_numrrsets * sizeof(dest[0])); 3745 dest += to->rep->ns_numrrsets; 3746 memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets, 3747 from->rep->ns_numrrsets * sizeof(dest[0])); 3748 dest += from->rep->ns_numrrsets; 3749 /* copy AR */ 3750 memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets+ 3751 to->rep->ns_numrrsets, 3752 to->rep->ar_numrrsets * sizeof(dest[0])); 3753 dest += to->rep->ar_numrrsets; 3754 memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets+ 3755 from->rep->ns_numrrsets, 3756 from->rep->ar_numrrsets * sizeof(dest[0])); 3757 /* update counts */ 3758 to->rep->rrsets = d; 3759 to->rep->an_numrrsets += from->rep->an_numrrsets; 3760 to->rep->ns_numrrsets += from->rep->ns_numrrsets; 3761 to->rep->ar_numrrsets += from->rep->ar_numrrsets; 3762 to->rep->rrset_count = n; 3763 } 3764 if(from->rep->security < to->rep->security) /* lowest sec */ 3765 to->rep->security = from->rep->security; 3766 if(from->rep->qdcount != 0) /* insert qd if appropriate */ 3767 to->rep->qdcount = from->rep->qdcount; 3768 if(from->rep->ttl < to->rep->ttl) /* use smallest TTL */ 3769 to->rep->ttl = from->rep->ttl; 3770 if(from->rep->prefetch_ttl < to->rep->prefetch_ttl) 3771 to->rep->prefetch_ttl = from->rep->prefetch_ttl; 3772 if(from->rep->serve_expired_ttl < to->rep->serve_expired_ttl) 3773 to->rep->serve_expired_ttl = from->rep->serve_expired_ttl; 3774 } 3775 /* are we done? */ 3776 foriq->num_current_queries --; 3777 if(foriq->num_current_queries == 0) 3778 foriq->state = FINISHED_STATE; 3779 } 3780 3781 /** 3782 * Collect class ANY responses and make them into one response. This 3783 * state is started and it creates queries for all classes (that have 3784 * root hints). The answers are then collected. 3785 * 3786 * @param qstate: query state. 3787 * @param id: module id. 3788 * @return true if the event needs more immediate processing, false if not. 3789 */ 3790 static int 3791 processCollectClass(struct module_qstate* qstate, int id) 3792 { 3793 struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id]; 3794 struct module_qstate* subq; 3795 /* If qchase.qclass == 0 then send out queries for all classes. 3796 * Otherwise, do nothing (wait for all answers to arrive and the 3797 * processClassResponse to put them together, and that moves us 3798 * towards the Finished state when done. */ 3799 if(iq->qchase.qclass == 0) { 3800 uint16_t c = 0; 3801 iq->qchase.qclass = LDNS_RR_CLASS_ANY; 3802 while(iter_get_next_root(qstate->env->hints, 3803 qstate->env->fwds, &c)) { 3804 /* generate query for this class */ 3805 log_nametypeclass(VERB_ALGO, "spawn collect query", 3806 qstate->qinfo.qname, qstate->qinfo.qtype, c); 3807 if(!generate_sub_request(qstate->qinfo.qname, 3808 qstate->qinfo.qname_len, qstate->qinfo.qtype, 3809 c, qstate, id, iq, INIT_REQUEST_STATE, 3810 FINISHED_STATE, &subq, 3811 (int)!(qstate->query_flags&BIT_CD), 0)) { 3812 errinf(qstate, "could not generate class ANY" 3813 " lookup query"); 3814 return error_response(qstate, id, 3815 LDNS_RCODE_SERVFAIL); 3816 } 3817 /* ignore subq, no special init required */ 3818 iq->num_current_queries ++; 3819 if(c == 0xffff) 3820 break; 3821 else c++; 3822 } 3823 /* if no roots are configured at all, return */ 3824 if(iq->num_current_queries == 0) { 3825 verbose(VERB_ALGO, "No root hints or fwds, giving up " 3826 "on qclass ANY"); 3827 return error_response(qstate, id, LDNS_RCODE_REFUSED); 3828 } 3829 /* return false, wait for queries to return */ 3830 } 3831 /* if woke up here because of an answer, wait for more answers */ 3832 return 0; 3833 } 3834 3835 /** 3836 * This handles the final state for first-tier responses (i.e., responses to 3837 * externally generated queries). 3838 * 3839 * @param qstate: query state. 3840 * @param iq: iterator query state. 3841 * @param id: module id. 3842 * @return true if the event needs more processing, false if not. Since this 3843 * is the final state for an event, it always returns false. 3844 */ 3845 static int 3846 processFinished(struct module_qstate* qstate, struct iter_qstate* iq, 3847 int id) 3848 { 3849 log_query_info(VERB_QUERY, "finishing processing for", 3850 &qstate->qinfo); 3851 3852 /* store negative cache element for parent side glue. */ 3853 if(!qstate->no_cache_store && iq->query_for_pside_glue 3854 && !iq->pside_glue) 3855 iter_store_parentside_neg(qstate->env, &qstate->qinfo, 3856 iq->deleg_msg?iq->deleg_msg->rep: 3857 (iq->response?iq->response->rep:NULL)); 3858 if(!iq->response) { 3859 verbose(VERB_ALGO, "No response is set, servfail"); 3860 errinf(qstate, "(no response found at query finish)"); 3861 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 3862 } 3863 3864 /* Make sure that the RA flag is set (since the presence of 3865 * this module means that recursion is available) */ 3866 iq->response->rep->flags |= BIT_RA; 3867 3868 /* Clear the AA flag */ 3869 /* FIXME: does this action go here or in some other module? */ 3870 iq->response->rep->flags &= ~BIT_AA; 3871 3872 /* make sure QR flag is on */ 3873 iq->response->rep->flags |= BIT_QR; 3874 3875 /* explicitly set the EDE string to NULL */ 3876 iq->response->rep->reason_bogus_str = NULL; 3877 3878 /* we have finished processing this query */ 3879 qstate->ext_state[id] = module_finished; 3880 3881 /* TODO: we are using a private TTL, trim the response. */ 3882 /* if (mPrivateTTL > 0){IterUtils.setPrivateTTL(resp, mPrivateTTL); } */ 3883 3884 /* prepend any items we have accumulated */ 3885 if(iq->an_prepend_list || iq->ns_prepend_list) { 3886 if(!iter_prepend(iq, iq->response, qstate->region)) { 3887 log_err("prepend rrsets: out of memory"); 3888 return error_response(qstate, id, LDNS_RCODE_SERVFAIL); 3889 } 3890 /* reset the query name back */ 3891 iq->response->qinfo = qstate->qinfo; 3892 /* the security state depends on the combination */ 3893 iq->response->rep->security = sec_status_unchecked; 3894 /* store message with the finished prepended items, 3895 * but only if we did recursion. The nonrecursion referral 3896 * from cache does not need to be stored in the msg cache. */ 3897 if(!qstate->no_cache_store && qstate->query_flags&BIT_RD) { 3898 iter_dns_store(qstate->env, &qstate->qinfo, 3899 iq->response->rep, 0, qstate->prefetch_leeway, 3900 iq->dp&&iq->dp->has_parent_side_NS, 3901 qstate->region, qstate->query_flags, 3902 qstate->qstarttime); 3903 } 3904 } 3905 qstate->return_rcode = LDNS_RCODE_NOERROR; 3906 qstate->return_msg = iq->response; 3907 return 0; 3908 } 3909 3910 /* 3911 * Return priming query results to interested super querystates. 3912 * 3913 * Sets the delegation point and delegation message (not nonRD queries). 3914 * This is a callback from walk_supers. 3915 * 3916 * @param qstate: query state that finished. 3917 * @param id: module id. 3918 * @param super: the qstate to inform. 3919 */ 3920 void 3921 iter_inform_super(struct module_qstate* qstate, int id, 3922 struct module_qstate* super) 3923 { 3924 if(!qstate->is_priming && super->qinfo.qclass == LDNS_RR_CLASS_ANY) 3925 processClassResponse(qstate, id, super); 3926 else if(super->qinfo.qtype == LDNS_RR_TYPE_DS && ((struct iter_qstate*) 3927 super->minfo[id])->state == DSNS_FIND_STATE) 3928 processDSNSResponse(qstate, id, super); 3929 else if(qstate->return_rcode != LDNS_RCODE_NOERROR) 3930 error_supers(qstate, id, super); 3931 else if(qstate->is_priming) 3932 prime_supers(qstate, id, super); 3933 else processTargetResponse(qstate, id, super); 3934 } 3935 3936 /** 3937 * Handle iterator state. 3938 * Handle events. This is the real processing loop for events, responsible 3939 * for moving events through the various states. If a processing method 3940 * returns true, then it will be advanced to the next state. If false, then 3941 * processing will stop. 3942 * 3943 * @param qstate: query state. 3944 * @param ie: iterator shared global environment. 3945 * @param iq: iterator query state. 3946 * @param id: module id. 3947 */ 3948 static void 3949 iter_handle(struct module_qstate* qstate, struct iter_qstate* iq, 3950 struct iter_env* ie, int id) 3951 { 3952 int cont = 1; 3953 while(cont) { 3954 verbose(VERB_ALGO, "iter_handle processing q with state %s", 3955 iter_state_to_string(iq->state)); 3956 switch(iq->state) { 3957 case INIT_REQUEST_STATE: 3958 cont = processInitRequest(qstate, iq, ie, id); 3959 break; 3960 case INIT_REQUEST_2_STATE: 3961 cont = processInitRequest2(qstate, iq, id); 3962 break; 3963 case INIT_REQUEST_3_STATE: 3964 cont = processInitRequest3(qstate, iq, id); 3965 break; 3966 case QUERYTARGETS_STATE: 3967 cont = processQueryTargets(qstate, iq, ie, id); 3968 break; 3969 case QUERY_RESP_STATE: 3970 cont = processQueryResponse(qstate, iq, ie, id); 3971 break; 3972 case PRIME_RESP_STATE: 3973 cont = processPrimeResponse(qstate, id); 3974 break; 3975 case COLLECT_CLASS_STATE: 3976 cont = processCollectClass(qstate, id); 3977 break; 3978 case DSNS_FIND_STATE: 3979 cont = processDSNSFind(qstate, iq, id); 3980 break; 3981 case FINISHED_STATE: 3982 cont = processFinished(qstate, iq, id); 3983 break; 3984 default: 3985 log_warn("iterator: invalid state: %d", 3986 iq->state); 3987 cont = 0; 3988 break; 3989 } 3990 } 3991 } 3992 3993 /** 3994 * This is the primary entry point for processing request events. Note that 3995 * this method should only be used by external modules. 3996 * @param qstate: query state. 3997 * @param ie: iterator shared global environment. 3998 * @param iq: iterator query state. 3999 * @param id: module id. 4000 */ 4001 static void 4002 process_request(struct module_qstate* qstate, struct iter_qstate* iq, 4003 struct iter_env* ie, int id) 4004 { 4005 /* external requests start in the INIT state, and finish using the 4006 * FINISHED state. */ 4007 iq->state = INIT_REQUEST_STATE; 4008 iq->final_state = FINISHED_STATE; 4009 verbose(VERB_ALGO, "process_request: new external request event"); 4010 iter_handle(qstate, iq, ie, id); 4011 } 4012 4013 /** process authoritative server reply */ 4014 static void 4015 process_response(struct module_qstate* qstate, struct iter_qstate* iq, 4016 struct iter_env* ie, int id, struct outbound_entry* outbound, 4017 enum module_ev event) 4018 { 4019 struct msg_parse* prs; 4020 struct edns_data edns; 4021 sldns_buffer* pkt; 4022 4023 verbose(VERB_ALGO, "process_response: new external response event"); 4024 iq->response = NULL; 4025 iq->state = QUERY_RESP_STATE; 4026 if(event == module_event_noreply || event == module_event_error) { 4027 if(event == module_event_noreply && iq->timeout_count >= 3 && 4028 qstate->env->cfg->use_caps_bits_for_id && 4029 !iq->caps_fallback && !is_caps_whitelisted(ie, iq)) { 4030 /* start fallback */ 4031 iq->caps_fallback = 1; 4032 iq->caps_server = 0; 4033 iq->caps_reply = NULL; 4034 iq->caps_response = NULL; 4035 iq->caps_minimisation_state = DONOT_MINIMISE_STATE; 4036 iq->state = QUERYTARGETS_STATE; 4037 iq->num_current_queries--; 4038 /* need fresh attempts for the 0x20 fallback, if 4039 * that was the cause for the failure */ 4040 iter_dec_attempts(iq->dp, 3, ie->outbound_msg_retry); 4041 verbose(VERB_DETAIL, "Capsforid: timeouts, starting fallback"); 4042 goto handle_it; 4043 } 4044 goto handle_it; 4045 } 4046 if( (event != module_event_reply && event != module_event_capsfail) 4047 || !qstate->reply) { 4048 log_err("Bad event combined with response"); 4049 outbound_list_remove(&iq->outlist, outbound); 4050 errinf(qstate, "module iterator received wrong internal event with a response message"); 4051 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); 4052 return; 4053 } 4054 4055 /* parse message */ 4056 fill_fail_addr(iq, &qstate->reply->remote_addr, 4057 qstate->reply->remote_addrlen); 4058 prs = (struct msg_parse*)regional_alloc(qstate->env->scratch, 4059 sizeof(struct msg_parse)); 4060 if(!prs) { 4061 log_err("out of memory on incoming message"); 4062 /* like packet got dropped */ 4063 goto handle_it; 4064 } 4065 memset(prs, 0, sizeof(*prs)); 4066 memset(&edns, 0, sizeof(edns)); 4067 pkt = qstate->reply->c->buffer; 4068 sldns_buffer_set_position(pkt, 0); 4069 if(parse_packet(pkt, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) { 4070 verbose(VERB_ALGO, "parse error on reply packet"); 4071 iq->parse_failures++; 4072 goto handle_it; 4073 } 4074 /* edns is not examined, but removed from message to help cache */ 4075 if(parse_extract_edns_from_response_msg(prs, &edns, qstate->env->scratch) != 4076 LDNS_RCODE_NOERROR) { 4077 iq->parse_failures++; 4078 goto handle_it; 4079 } 4080 4081 /* Copy the edns options we may got from the back end */ 4082 if(edns.opt_list_in) { 4083 qstate->edns_opts_back_in = edns_opt_copy_region(edns.opt_list_in, 4084 qstate->region); 4085 if(!qstate->edns_opts_back_in) { 4086 log_err("out of memory on incoming message"); 4087 /* like packet got dropped */ 4088 goto handle_it; 4089 } 4090 if(!inplace_cb_edns_back_parsed_call(qstate->env, qstate)) { 4091 log_err("unable to call edns_back_parsed callback"); 4092 goto handle_it; 4093 } 4094 } 4095 4096 /* remove CD-bit, we asked for in case we handle validation ourself */ 4097 prs->flags &= ~BIT_CD; 4098 4099 /* normalize and sanitize: easy to delete items from linked lists */ 4100 if(!scrub_message(pkt, prs, &iq->qinfo_out, iq->dp->name, 4101 qstate->env->scratch, qstate->env, ie)) { 4102 /* if 0x20 enabled, start fallback, but we have no message */ 4103 if(event == module_event_capsfail && !iq->caps_fallback) { 4104 iq->caps_fallback = 1; 4105 iq->caps_server = 0; 4106 iq->caps_reply = NULL; 4107 iq->caps_response = NULL; 4108 iq->caps_minimisation_state = DONOT_MINIMISE_STATE; 4109 iq->state = QUERYTARGETS_STATE; 4110 iq->num_current_queries--; 4111 verbose(VERB_DETAIL, "Capsforid: scrub failed, starting fallback with no response"); 4112 } 4113 iq->scrub_failures++; 4114 goto handle_it; 4115 } 4116 4117 /* allocate response dns_msg in region */ 4118 iq->response = dns_alloc_msg(pkt, prs, qstate->region); 4119 if(!iq->response) 4120 goto handle_it; 4121 log_query_info(VERB_DETAIL, "response for", &qstate->qinfo); 4122 log_name_addr(VERB_DETAIL, "reply from", iq->dp->name, 4123 &qstate->reply->remote_addr, qstate->reply->remote_addrlen); 4124 if(verbosity >= VERB_ALGO) 4125 log_dns_msg("incoming scrubbed packet:", &iq->response->qinfo, 4126 iq->response->rep); 4127 4128 if(event == module_event_capsfail || iq->caps_fallback) { 4129 if(qstate->env->cfg->qname_minimisation && 4130 iq->minimisation_state != DONOT_MINIMISE_STATE) { 4131 /* Skip QNAME minimisation for next query, since that 4132 * one has to match the current query. */ 4133 iq->minimisation_state = SKIP_MINIMISE_STATE; 4134 } 4135 /* for fallback we care about main answer, not additionals */ 4136 /* removing that makes comparison more likely to succeed */ 4137 caps_strip_reply(iq->response->rep); 4138 4139 if(iq->caps_fallback && 4140 iq->caps_minimisation_state != iq->minimisation_state) { 4141 /* QNAME minimisation state has changed, restart caps 4142 * fallback. */ 4143 iq->caps_fallback = 0; 4144 } 4145 4146 if(!iq->caps_fallback) { 4147 /* start fallback */ 4148 iq->caps_fallback = 1; 4149 iq->caps_server = 0; 4150 iq->caps_reply = iq->response->rep; 4151 iq->caps_response = iq->response; 4152 iq->caps_minimisation_state = iq->minimisation_state; 4153 iq->state = QUERYTARGETS_STATE; 4154 iq->num_current_queries--; 4155 verbose(VERB_DETAIL, "Capsforid: starting fallback"); 4156 goto handle_it; 4157 } else { 4158 /* check if reply is the same, otherwise, fail */ 4159 if(!iq->caps_reply) { 4160 iq->caps_reply = iq->response->rep; 4161 iq->caps_response = iq->response; 4162 iq->caps_server = -1; /*become zero at ++, 4163 so that we start the full set of trials */ 4164 } else if(caps_failed_rcode(iq->caps_reply) && 4165 !caps_failed_rcode(iq->response->rep)) { 4166 /* prefer to upgrade to non-SERVFAIL */ 4167 iq->caps_reply = iq->response->rep; 4168 iq->caps_response = iq->response; 4169 } else if(!caps_failed_rcode(iq->caps_reply) && 4170 caps_failed_rcode(iq->response->rep)) { 4171 /* if we have non-SERVFAIL as answer then 4172 * we can ignore SERVFAILs for the equality 4173 * comparison */ 4174 /* no instructions here, skip other else */ 4175 } else if(caps_failed_rcode(iq->caps_reply) && 4176 caps_failed_rcode(iq->response->rep)) { 4177 /* failure is same as other failure in fallbk*/ 4178 /* no instructions here, skip other else */ 4179 } else if(!reply_equal(iq->response->rep, iq->caps_reply, 4180 qstate->env->scratch)) { 4181 verbose(VERB_DETAIL, "Capsforid fallback: " 4182 "getting different replies, failed"); 4183 outbound_list_remove(&iq->outlist, outbound); 4184 errinf(qstate, "0x20 failed, then got different replies in fallback"); 4185 (void)error_response(qstate, id, 4186 LDNS_RCODE_SERVFAIL); 4187 return; 4188 } 4189 /* continue the fallback procedure at next server */ 4190 iq->caps_server++; 4191 iq->state = QUERYTARGETS_STATE; 4192 iq->num_current_queries--; 4193 verbose(VERB_DETAIL, "Capsforid: reply is equal. " 4194 "go to next fallback"); 4195 goto handle_it; 4196 } 4197 } 4198 iq->caps_fallback = 0; /* if we were in fallback, 0x20 is OK now */ 4199 4200 handle_it: 4201 outbound_list_remove(&iq->outlist, outbound); 4202 iter_handle(qstate, iq, ie, id); 4203 } 4204 4205 void 4206 iter_operate(struct module_qstate* qstate, enum module_ev event, int id, 4207 struct outbound_entry* outbound) 4208 { 4209 struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id]; 4210 struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id]; 4211 verbose(VERB_QUERY, "iterator[module %d] operate: extstate:%s event:%s", 4212 id, strextstate(qstate->ext_state[id]), strmodulevent(event)); 4213 if(iq) log_query_info(VERB_QUERY, "iterator operate: query", 4214 &qstate->qinfo); 4215 if(iq && qstate->qinfo.qname != iq->qchase.qname) 4216 log_query_info(VERB_QUERY, "iterator operate: chased to", 4217 &iq->qchase); 4218 4219 /* perform iterator state machine */ 4220 if((event == module_event_new || event == module_event_pass) && 4221 iq == NULL) { 4222 if(!iter_new(qstate, id)) { 4223 errinf(qstate, "malloc failure, new iterator module allocation"); 4224 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); 4225 return; 4226 } 4227 iq = (struct iter_qstate*)qstate->minfo[id]; 4228 process_request(qstate, iq, ie, id); 4229 return; 4230 } 4231 if(iq && event == module_event_pass) { 4232 iter_handle(qstate, iq, ie, id); 4233 return; 4234 } 4235 if(iq && outbound) { 4236 process_response(qstate, iq, ie, id, outbound, event); 4237 return; 4238 } 4239 if(event == module_event_error) { 4240 verbose(VERB_ALGO, "got called with event error, giving up"); 4241 errinf(qstate, "iterator module got the error event"); 4242 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); 4243 return; 4244 } 4245 4246 log_err("bad event for iterator"); 4247 errinf(qstate, "iterator module received wrong event"); 4248 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); 4249 } 4250 4251 void 4252 iter_clear(struct module_qstate* qstate, int id) 4253 { 4254 struct iter_qstate* iq; 4255 if(!qstate) 4256 return; 4257 iq = (struct iter_qstate*)qstate->minfo[id]; 4258 if(iq) { 4259 outbound_list_clear(&iq->outlist); 4260 if(iq->target_count && --iq->target_count[TARGET_COUNT_REF] == 0) { 4261 free(iq->target_count); 4262 if(*iq->nxns_dp) free(*iq->nxns_dp); 4263 free(iq->nxns_dp); 4264 } 4265 iq->num_current_queries = 0; 4266 } 4267 qstate->minfo[id] = NULL; 4268 } 4269 4270 size_t 4271 iter_get_mem(struct module_env* env, int id) 4272 { 4273 struct iter_env* ie = (struct iter_env*)env->modinfo[id]; 4274 if(!ie) 4275 return 0; 4276 return sizeof(*ie) + sizeof(int)*((size_t)ie->max_dependency_depth+1) 4277 + donotq_get_mem(ie->donotq) + priv_get_mem(ie->priv); 4278 } 4279 4280 /** 4281 * The iterator function block 4282 */ 4283 static struct module_func_block iter_block = { 4284 "iterator", 4285 &iter_init, &iter_deinit, &iter_operate, &iter_inform_super, 4286 &iter_clear, &iter_get_mem 4287 }; 4288 4289 struct module_func_block* 4290 iter_get_funcblock(void) 4291 { 4292 return &iter_block; 4293 } 4294 4295 const char* 4296 iter_state_to_string(enum iter_state state) 4297 { 4298 switch (state) 4299 { 4300 case INIT_REQUEST_STATE : 4301 return "INIT REQUEST STATE"; 4302 case INIT_REQUEST_2_STATE : 4303 return "INIT REQUEST STATE (stage 2)"; 4304 case INIT_REQUEST_3_STATE: 4305 return "INIT REQUEST STATE (stage 3)"; 4306 case QUERYTARGETS_STATE : 4307 return "QUERY TARGETS STATE"; 4308 case PRIME_RESP_STATE : 4309 return "PRIME RESPONSE STATE"; 4310 case COLLECT_CLASS_STATE : 4311 return "COLLECT CLASS STATE"; 4312 case DSNS_FIND_STATE : 4313 return "DSNS FIND STATE"; 4314 case QUERY_RESP_STATE : 4315 return "QUERY RESPONSE STATE"; 4316 case FINISHED_STATE : 4317 return "FINISHED RESPONSE STATE"; 4318 default : 4319 return "UNKNOWN ITER STATE"; 4320 } 4321 } 4322 4323 int 4324 iter_state_is_responsestate(enum iter_state s) 4325 { 4326 switch(s) { 4327 case INIT_REQUEST_STATE : 4328 case INIT_REQUEST_2_STATE : 4329 case INIT_REQUEST_3_STATE : 4330 case QUERYTARGETS_STATE : 4331 case COLLECT_CLASS_STATE : 4332 return 0; 4333 default: 4334 break; 4335 } 4336 return 1; 4337 } 4338