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/rrset.h"
56 #include "services/cache/infra.h"
57 #include "services/authzone.h"
58 #include "util/module.h"
59 #include "util/netevent.h"
60 #include "util/net_help.h"
61 #include "util/regional.h"
62 #include "util/data/dname.h"
63 #include "util/data/msgencode.h"
64 #include "util/fptr_wlist.h"
65 #include "util/config_file.h"
66 #include "util/random.h"
67 #include "sldns/rrdef.h"
68 #include "sldns/wire2str.h"
69 #include "sldns/str2wire.h"
70 #include "sldns/parseutil.h"
71 #include "sldns/sbuffer.h"
72
73 /* in msec */
74 int UNKNOWN_SERVER_NICENESS = 376;
75 /* in msec */
76 int USEFUL_SERVER_TOP_TIMEOUT = 120000;
77 /* Equals USEFUL_SERVER_TOP_TIMEOUT*4 */
78 int BLACKLIST_PENALTY = (120000*4);
79
80 static void target_count_increase_nx(struct iter_qstate* iq, int num);
81
82 int
iter_init(struct module_env * env,int id)83 iter_init(struct module_env* env, int id)
84 {
85 struct iter_env* iter_env = (struct iter_env*)calloc(1,
86 sizeof(struct iter_env));
87 if(!iter_env) {
88 log_err("malloc failure");
89 return 0;
90 }
91 env->modinfo[id] = (void*)iter_env;
92
93 lock_basic_init(&iter_env->queries_ratelimit_lock);
94 lock_protect(&iter_env->queries_ratelimit_lock,
95 &iter_env->num_queries_ratelimited,
96 sizeof(iter_env->num_queries_ratelimited));
97
98 if(!iter_apply_cfg(iter_env, env->cfg)) {
99 log_err("iterator: could not apply configuration settings.");
100 return 0;
101 }
102
103 return 1;
104 }
105
106 /** delete caps_whitelist element */
107 static void
caps_free(struct rbnode_type * n,void * ATTR_UNUSED (d))108 caps_free(struct rbnode_type* n, void* ATTR_UNUSED(d))
109 {
110 if(n) {
111 free(((struct name_tree_node*)n)->name);
112 free(n);
113 }
114 }
115
116 void
iter_deinit(struct module_env * env,int id)117 iter_deinit(struct module_env* env, int id)
118 {
119 struct iter_env* iter_env;
120 if(!env || !env->modinfo[id])
121 return;
122 iter_env = (struct iter_env*)env->modinfo[id];
123 lock_basic_destroy(&iter_env->queries_ratelimit_lock);
124 free(iter_env->target_fetch_policy);
125 priv_delete(iter_env->priv);
126 donotq_delete(iter_env->donotq);
127 if(iter_env->caps_white) {
128 traverse_postorder(iter_env->caps_white, caps_free, NULL);
129 free(iter_env->caps_white);
130 }
131 free(iter_env);
132 env->modinfo[id] = NULL;
133 }
134
135 /** new query for iterator */
136 static int
iter_new(struct module_qstate * qstate,int id)137 iter_new(struct module_qstate* qstate, int id)
138 {
139 struct iter_qstate* iq = (struct iter_qstate*)regional_alloc(
140 qstate->region, sizeof(struct iter_qstate));
141 qstate->minfo[id] = iq;
142 if(!iq)
143 return 0;
144 memset(iq, 0, sizeof(*iq));
145 iq->state = INIT_REQUEST_STATE;
146 iq->final_state = FINISHED_STATE;
147 iq->an_prepend_list = NULL;
148 iq->an_prepend_last = NULL;
149 iq->ns_prepend_list = NULL;
150 iq->ns_prepend_last = NULL;
151 iq->dp = NULL;
152 iq->depth = 0;
153 iq->num_target_queries = 0;
154 iq->num_current_queries = 0;
155 iq->query_restart_count = 0;
156 iq->referral_count = 0;
157 iq->sent_count = 0;
158 iq->ratelimit_ok = 0;
159 iq->target_count = NULL;
160 iq->dp_target_count = 0;
161 iq->wait_priming_stub = 0;
162 iq->refetch_glue = 0;
163 iq->dnssec_expected = 0;
164 iq->dnssec_lame_query = 0;
165 iq->chase_flags = qstate->query_flags;
166 /* Start with the (current) qname. */
167 iq->qchase = qstate->qinfo;
168 outbound_list_init(&iq->outlist);
169 iq->minimise_count = 0;
170 iq->timeout_count = 0;
171 if (qstate->env->cfg->qname_minimisation)
172 iq->minimisation_state = INIT_MINIMISE_STATE;
173 else
174 iq->minimisation_state = DONOT_MINIMISE_STATE;
175
176 memset(&iq->qinfo_out, 0, sizeof(struct query_info));
177 return 1;
178 }
179
180 /**
181 * Transition to the next state. This can be used to advance a currently
182 * processing event. It cannot be used to reactivate a forEvent.
183 *
184 * @param iq: iterator query state
185 * @param nextstate The state to transition to.
186 * @return true. This is so this can be called as the return value for the
187 * actual process*State() methods. (Transitioning to the next state
188 * implies further processing).
189 */
190 static int
next_state(struct iter_qstate * iq,enum iter_state nextstate)191 next_state(struct iter_qstate* iq, enum iter_state nextstate)
192 {
193 /* If transitioning to a "response" state, make sure that there is a
194 * response */
195 if(iter_state_is_responsestate(nextstate)) {
196 if(iq->response == NULL) {
197 log_err("transitioning to response state sans "
198 "response.");
199 }
200 }
201 iq->state = nextstate;
202 return 1;
203 }
204
205 /**
206 * Transition an event to its final state. Final states always either return
207 * a result up the module chain, or reactivate a dependent event. Which
208 * final state to transition to is set in the module state for the event when
209 * it was created, and depends on the original purpose of the event.
210 *
211 * The response is stored in the qstate->buf buffer.
212 *
213 * @param iq: iterator query state
214 * @return false. This is so this method can be used as the return value for
215 * the processState methods. (Transitioning to the final state
216 */
217 static int
final_state(struct iter_qstate * iq)218 final_state(struct iter_qstate* iq)
219 {
220 return next_state(iq, iq->final_state);
221 }
222
223 /**
224 * Callback routine to handle errors in parent query states
225 * @param qstate: query state that failed.
226 * @param id: module id.
227 * @param super: super state.
228 */
229 static void
error_supers(struct module_qstate * qstate,int id,struct module_qstate * super)230 error_supers(struct module_qstate* qstate, int id, struct module_qstate* super)
231 {
232 struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
233 struct iter_qstate* super_iq = (struct iter_qstate*)super->minfo[id];
234
235 if(qstate->qinfo.qtype == LDNS_RR_TYPE_A ||
236 qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA) {
237 /* mark address as failed. */
238 struct delegpt_ns* dpns = NULL;
239 super_iq->num_target_queries--;
240 if(super_iq->dp)
241 dpns = delegpt_find_ns(super_iq->dp,
242 qstate->qinfo.qname, qstate->qinfo.qname_len);
243 if(!dpns) {
244 /* not interested */
245 /* this can happen, for eg. qname minimisation asked
246 * for an NXDOMAIN to be validated, and used qtype
247 * A for that, and the error of that, the name, is
248 * not listed in super_iq->dp */
249 verbose(VERB_ALGO, "subq error, but not interested");
250 log_query_info(VERB_ALGO, "superq", &super->qinfo);
251 return;
252 } else {
253 /* see if the failure did get (parent-lame) info */
254 if(!cache_fill_missing(super->env, super_iq->qchase.qclass,
255 super->region, super_iq->dp))
256 log_err("out of memory adding missing");
257 }
258 delegpt_mark_neg(dpns, qstate->qinfo.qtype);
259 if((dpns->got4 == 2 || (!ie->supports_ipv4 && !ie->use_nat64)) &&
260 (dpns->got6 == 2 || !ie->supports_ipv6)) {
261 dpns->resolved = 1; /* mark as failed */
262 target_count_increase_nx(super_iq, 1);
263 }
264 }
265 if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS) {
266 /* prime failed to get delegation */
267 super_iq->dp = NULL;
268 }
269 /* evaluate targets again */
270 super_iq->state = QUERYTARGETS_STATE;
271 /* super becomes runnable, and will process this change */
272 }
273
274 /**
275 * Return an error to the client
276 * @param qstate: our query state
277 * @param id: module id
278 * @param rcode: error code (DNS errcode).
279 * @return: 0 for use by caller, to make notation easy, like:
280 * return error_response(..).
281 */
282 static int
error_response(struct module_qstate * qstate,int id,int rcode)283 error_response(struct module_qstate* qstate, int id, int rcode)
284 {
285 verbose(VERB_QUERY, "return error response %s",
286 sldns_lookup_by_id(sldns_rcodes, rcode)?
287 sldns_lookup_by_id(sldns_rcodes, rcode)->name:"??");
288 qstate->return_rcode = rcode;
289 qstate->return_msg = NULL;
290 qstate->ext_state[id] = module_finished;
291 return 0;
292 }
293
294 /**
295 * Return an error to the client and cache the error code in the
296 * message cache (so per qname, qtype, qclass).
297 * @param qstate: our query state
298 * @param id: module id
299 * @param rcode: error code (DNS errcode).
300 * @return: 0 for use by caller, to make notation easy, like:
301 * return error_response(..).
302 */
303 static int
error_response_cache(struct module_qstate * qstate,int id,int rcode)304 error_response_cache(struct module_qstate* qstate, int id, int rcode)
305 {
306 struct reply_info err;
307 struct msgreply_entry* msg;
308 if(qstate->no_cache_store) {
309 return error_response(qstate, id, rcode);
310 }
311 if(qstate->prefetch_leeway > NORR_TTL) {
312 verbose(VERB_ALGO, "error response for prefetch in cache");
313 /* attempt to adjust the cache entry prefetch */
314 if(dns_cache_prefetch_adjust(qstate->env, &qstate->qinfo,
315 NORR_TTL, qstate->query_flags))
316 return error_response(qstate, id, rcode);
317 /* if that fails (not in cache), fall through to store err */
318 }
319 if((msg=msg_cache_lookup(qstate->env,
320 qstate->qinfo.qname, qstate->qinfo.qname_len,
321 qstate->qinfo.qtype, qstate->qinfo.qclass,
322 qstate->query_flags, 0,
323 qstate->env->cfg->serve_expired_ttl_reset)) != NULL) {
324 struct reply_info* rep = (struct reply_info*)msg->entry.data;
325 if(qstate->env->cfg->serve_expired &&
326 qstate->env->cfg->serve_expired_ttl_reset && rep &&
327 *qstate->env->now + qstate->env->cfg->serve_expired_ttl
328 > rep->serve_expired_ttl) {
329 verbose(VERB_ALGO, "reset serve-expired-ttl for "
330 "response in cache");
331 rep->serve_expired_ttl = *qstate->env->now +
332 qstate->env->cfg->serve_expired_ttl;
333 }
334 if(rep && (FLAGS_GET_RCODE(rep->flags) ==
335 LDNS_RCODE_NOERROR ||
336 FLAGS_GET_RCODE(rep->flags) ==
337 LDNS_RCODE_NXDOMAIN ||
338 FLAGS_GET_RCODE(rep->flags) ==
339 LDNS_RCODE_YXDOMAIN) &&
340 (qstate->env->cfg->serve_expired ||
341 *qstate->env->now <= rep->ttl)) {
342 /* we have a good entry, don't overwrite */
343 lock_rw_unlock(&msg->entry.lock);
344 return error_response(qstate, id, rcode);
345 }
346 lock_rw_unlock(&msg->entry.lock);
347 /* nothing interesting is cached (already error response or
348 * expired good record when we don't serve expired), so this
349 * servfail cache entry is useful (stops waste of time on this
350 * servfail NORR_TTL) */
351 }
352 /* store in cache */
353 memset(&err, 0, sizeof(err));
354 err.flags = (uint16_t)(BIT_QR | BIT_RA);
355 FLAGS_SET_RCODE(err.flags, rcode);
356 err.qdcount = 1;
357 err.ttl = NORR_TTL;
358 err.prefetch_ttl = PREFETCH_TTL_CALC(err.ttl);
359 err.serve_expired_ttl = NORR_TTL;
360 /* do not waste time trying to validate this servfail */
361 err.security = sec_status_indeterminate;
362 verbose(VERB_ALGO, "store error response in message cache");
363 iter_dns_store(qstate->env, &qstate->qinfo, &err, 0, 0, 0, NULL,
364 qstate->query_flags, qstate->qstarttime);
365 return error_response(qstate, id, rcode);
366 }
367
368 /** check if prepend item is duplicate item */
369 static int
prepend_is_duplicate(struct ub_packed_rrset_key ** sets,size_t to,struct ub_packed_rrset_key * dup)370 prepend_is_duplicate(struct ub_packed_rrset_key** sets, size_t to,
371 struct ub_packed_rrset_key* dup)
372 {
373 size_t i;
374 for(i=0; i<to; i++) {
375 if(sets[i]->rk.type == dup->rk.type &&
376 sets[i]->rk.rrset_class == dup->rk.rrset_class &&
377 sets[i]->rk.dname_len == dup->rk.dname_len &&
378 query_dname_compare(sets[i]->rk.dname, dup->rk.dname)
379 == 0)
380 return 1;
381 }
382 return 0;
383 }
384
385 /** prepend the prepend list in the answer and authority section of dns_msg */
386 static int
iter_prepend(struct iter_qstate * iq,struct dns_msg * msg,struct regional * region)387 iter_prepend(struct iter_qstate* iq, struct dns_msg* msg,
388 struct regional* region)
389 {
390 struct iter_prep_list* p;
391 struct ub_packed_rrset_key** sets;
392 size_t num_an = 0, num_ns = 0;;
393 for(p = iq->an_prepend_list; p; p = p->next)
394 num_an++;
395 for(p = iq->ns_prepend_list; p; p = p->next)
396 num_ns++;
397 if(num_an + num_ns == 0)
398 return 1;
399 verbose(VERB_ALGO, "prepending %d rrsets", (int)num_an + (int)num_ns);
400 if(num_an > RR_COUNT_MAX || num_ns > RR_COUNT_MAX ||
401 msg->rep->rrset_count > RR_COUNT_MAX) return 0; /* overflow */
402 sets = regional_alloc(region, (num_an+num_ns+msg->rep->rrset_count) *
403 sizeof(struct ub_packed_rrset_key*));
404 if(!sets)
405 return 0;
406 /* ANSWER section */
407 num_an = 0;
408 for(p = iq->an_prepend_list; p; p = p->next) {
409 sets[num_an++] = p->rrset;
410 if(ub_packed_rrset_ttl(p->rrset) < msg->rep->ttl)
411 msg->rep->ttl = ub_packed_rrset_ttl(p->rrset);
412 }
413 memcpy(sets+num_an, msg->rep->rrsets, msg->rep->an_numrrsets *
414 sizeof(struct ub_packed_rrset_key*));
415 /* AUTH section */
416 num_ns = 0;
417 for(p = iq->ns_prepend_list; p; p = p->next) {
418 if(prepend_is_duplicate(sets+msg->rep->an_numrrsets+num_an,
419 num_ns, p->rrset) || prepend_is_duplicate(
420 msg->rep->rrsets+msg->rep->an_numrrsets,
421 msg->rep->ns_numrrsets, p->rrset))
422 continue;
423 sets[msg->rep->an_numrrsets + num_an + num_ns++] = p->rrset;
424 if(ub_packed_rrset_ttl(p->rrset) < msg->rep->ttl)
425 msg->rep->ttl = ub_packed_rrset_ttl(p->rrset);
426 }
427 memcpy(sets + num_an + msg->rep->an_numrrsets + num_ns,
428 msg->rep->rrsets + msg->rep->an_numrrsets,
429 (msg->rep->ns_numrrsets + msg->rep->ar_numrrsets) *
430 sizeof(struct ub_packed_rrset_key*));
431
432 /* NXDOMAIN rcode can stay if we prepended DNAME/CNAMEs, because
433 * this is what recursors should give. */
434 msg->rep->rrset_count += num_an + num_ns;
435 msg->rep->an_numrrsets += num_an;
436 msg->rep->ns_numrrsets += num_ns;
437 msg->rep->rrsets = sets;
438 return 1;
439 }
440
441 /**
442 * Find rrset in ANSWER prepend list.
443 * to avoid duplicate DNAMEs when a DNAME is traversed twice.
444 * @param iq: iterator query state.
445 * @param rrset: rrset to add.
446 * @return false if not found
447 */
448 static int
iter_find_rrset_in_prepend_answer(struct iter_qstate * iq,struct ub_packed_rrset_key * rrset)449 iter_find_rrset_in_prepend_answer(struct iter_qstate* iq,
450 struct ub_packed_rrset_key* rrset)
451 {
452 struct iter_prep_list* p = iq->an_prepend_list;
453 while(p) {
454 if(ub_rrset_compare(p->rrset, rrset) == 0 &&
455 rrsetdata_equal((struct packed_rrset_data*)p->rrset
456 ->entry.data, (struct packed_rrset_data*)rrset
457 ->entry.data))
458 return 1;
459 p = p->next;
460 }
461 return 0;
462 }
463
464 /**
465 * Add rrset to ANSWER prepend list
466 * @param qstate: query state.
467 * @param iq: iterator query state.
468 * @param rrset: rrset to add.
469 * @return false on failure (malloc).
470 */
471 static int
iter_add_prepend_answer(struct module_qstate * qstate,struct iter_qstate * iq,struct ub_packed_rrset_key * rrset)472 iter_add_prepend_answer(struct module_qstate* qstate, struct iter_qstate* iq,
473 struct ub_packed_rrset_key* rrset)
474 {
475 struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc(
476 qstate->region, sizeof(struct iter_prep_list));
477 if(!p)
478 return 0;
479 p->rrset = rrset;
480 p->next = NULL;
481 /* add at end */
482 if(iq->an_prepend_last)
483 iq->an_prepend_last->next = p;
484 else iq->an_prepend_list = p;
485 iq->an_prepend_last = p;
486 return 1;
487 }
488
489 /**
490 * Add rrset to AUTHORITY prepend list
491 * @param qstate: query state.
492 * @param iq: iterator query state.
493 * @param rrset: rrset to add.
494 * @return false on failure (malloc).
495 */
496 static int
iter_add_prepend_auth(struct module_qstate * qstate,struct iter_qstate * iq,struct ub_packed_rrset_key * rrset)497 iter_add_prepend_auth(struct module_qstate* qstate, struct iter_qstate* iq,
498 struct ub_packed_rrset_key* rrset)
499 {
500 struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc(
501 qstate->region, sizeof(struct iter_prep_list));
502 if(!p)
503 return 0;
504 p->rrset = rrset;
505 p->next = NULL;
506 /* add at end */
507 if(iq->ns_prepend_last)
508 iq->ns_prepend_last->next = p;
509 else iq->ns_prepend_list = p;
510 iq->ns_prepend_last = p;
511 return 1;
512 }
513
514 /**
515 * Given a CNAME response (defined as a response containing a CNAME or DNAME
516 * that does not answer the request), process the response, modifying the
517 * state as necessary. This follows the CNAME/DNAME chain and returns the
518 * final query name.
519 *
520 * sets the new query name, after following the CNAME/DNAME chain.
521 * @param qstate: query state.
522 * @param iq: iterator query state.
523 * @param msg: the response.
524 * @param mname: returned target new query name.
525 * @param mname_len: length of mname.
526 * @return false on (malloc) error.
527 */
528 static int
handle_cname_response(struct module_qstate * qstate,struct iter_qstate * iq,struct dns_msg * msg,uint8_t ** mname,size_t * mname_len)529 handle_cname_response(struct module_qstate* qstate, struct iter_qstate* iq,
530 struct dns_msg* msg, uint8_t** mname, size_t* mname_len)
531 {
532 size_t i;
533 /* Start with the (current) qname. */
534 *mname = iq->qchase.qname;
535 *mname_len = iq->qchase.qname_len;
536
537 /* Iterate over the ANSWER rrsets in order, looking for CNAMEs and
538 * DNAMES. */
539 for(i=0; i<msg->rep->an_numrrsets; i++) {
540 struct ub_packed_rrset_key* r = msg->rep->rrsets[i];
541 /* If there is a (relevant) DNAME, add it to the list.
542 * We always expect there to be CNAME that was generated
543 * by this DNAME following, so we don't process the DNAME
544 * directly. */
545 if(ntohs(r->rk.type) == LDNS_RR_TYPE_DNAME &&
546 dname_strict_subdomain_c(*mname, r->rk.dname) &&
547 !iter_find_rrset_in_prepend_answer(iq, r)) {
548 if(!iter_add_prepend_answer(qstate, iq, r))
549 return 0;
550 continue;
551 }
552
553 if(ntohs(r->rk.type) == LDNS_RR_TYPE_CNAME &&
554 query_dname_compare(*mname, r->rk.dname) == 0 &&
555 !iter_find_rrset_in_prepend_answer(iq, r)) {
556 /* Add this relevant CNAME rrset to the prepend list.*/
557 if(!iter_add_prepend_answer(qstate, iq, r))
558 return 0;
559 get_cname_target(r, mname, mname_len);
560 }
561
562 /* Other rrsets in the section are ignored. */
563 }
564 /* add authority rrsets to authority prepend, for wildcarded CNAMEs */
565 for(i=msg->rep->an_numrrsets; i<msg->rep->an_numrrsets +
566 msg->rep->ns_numrrsets; i++) {
567 struct ub_packed_rrset_key* r = msg->rep->rrsets[i];
568 /* only add NSEC/NSEC3, as they may be needed for validation */
569 if(ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC ||
570 ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC3) {
571 if(!iter_add_prepend_auth(qstate, iq, r))
572 return 0;
573 }
574 }
575 return 1;
576 }
577
578 /** fill fail address for later recovery */
579 static void
fill_fail_addr(struct iter_qstate * iq,struct sockaddr_storage * addr,socklen_t addrlen)580 fill_fail_addr(struct iter_qstate* iq, struct sockaddr_storage* addr,
581 socklen_t addrlen)
582 {
583 if(addrlen == 0) {
584 iq->fail_addr_type = 0;
585 return;
586 }
587 if(((struct sockaddr_in*)addr)->sin_family == AF_INET) {
588 iq->fail_addr_type = 4;
589 memcpy(&iq->fail_addr.in,
590 &((struct sockaddr_in*)addr)->sin_addr,
591 sizeof(iq->fail_addr.in));
592 }
593 #ifdef AF_INET6
594 else if(((struct sockaddr_in*)addr)->sin_family == AF_INET6) {
595 iq->fail_addr_type = 6;
596 memcpy(&iq->fail_addr.in6,
597 &((struct sockaddr_in6*)addr)->sin6_addr,
598 sizeof(iq->fail_addr.in6));
599 }
600 #endif
601 else {
602 iq->fail_addr_type = 0;
603 }
604 }
605
606 /** print fail addr to string */
607 static void
print_fail_addr(struct iter_qstate * iq,char * buf,size_t len)608 print_fail_addr(struct iter_qstate* iq, char* buf, size_t len)
609 {
610 if(iq->fail_addr_type == 4) {
611 if(inet_ntop(AF_INET, &iq->fail_addr.in, buf,
612 (socklen_t)len) == 0)
613 (void)strlcpy(buf, "(inet_ntop error)", len);
614 }
615 #ifdef AF_INET6
616 else if(iq->fail_addr_type == 6) {
617 if(inet_ntop(AF_INET6, &iq->fail_addr.in6, buf,
618 (socklen_t)len) == 0)
619 (void)strlcpy(buf, "(inet_ntop error)", len);
620 }
621 #endif
622 else
623 (void)strlcpy(buf, "", len);
624 }
625
626 /** add response specific error information for log servfail */
627 static void
errinf_reply(struct module_qstate * qstate,struct iter_qstate * iq)628 errinf_reply(struct module_qstate* qstate, struct iter_qstate* iq)
629 {
630 if(qstate->env->cfg->val_log_level < 2 && !qstate->env->cfg->log_servfail)
631 return;
632 if((qstate->reply && qstate->reply->remote_addrlen != 0) ||
633 (iq->fail_addr_type != 0)) {
634 char from[256], frm[512];
635 if(qstate->reply && qstate->reply->remote_addrlen != 0)
636 addr_to_str(&qstate->reply->remote_addr,
637 qstate->reply->remote_addrlen, from,
638 sizeof(from));
639 else
640 print_fail_addr(iq, from, sizeof(from));
641 snprintf(frm, sizeof(frm), "from %s", from);
642 errinf(qstate, frm);
643 }
644 if(iq->scrub_failures || iq->parse_failures) {
645 if(iq->scrub_failures)
646 errinf(qstate, "upstream response failed scrub");
647 if(iq->parse_failures)
648 errinf(qstate, "could not parse upstream response");
649 } else if(iq->response == NULL && iq->timeout_count != 0) {
650 errinf(qstate, "upstream server timeout");
651 } else if(iq->response == NULL) {
652 errinf(qstate, "no server to query");
653 if(iq->dp) {
654 if(iq->dp->target_list == NULL)
655 errinf(qstate, "no addresses for nameservers");
656 else errinf(qstate, "nameserver addresses not usable");
657 if(iq->dp->nslist == NULL)
658 errinf(qstate, "have no nameserver names");
659 if(iq->dp->bogus)
660 errinf(qstate, "NS record was dnssec bogus");
661 }
662 }
663 if(iq->response && iq->response->rep) {
664 if(FLAGS_GET_RCODE(iq->response->rep->flags) != 0) {
665 char rcode[256], rc[32];
666 (void)sldns_wire2str_rcode_buf(
667 FLAGS_GET_RCODE(iq->response->rep->flags),
668 rc, sizeof(rc));
669 snprintf(rcode, sizeof(rcode), "got %s", rc);
670 errinf(qstate, rcode);
671 } else {
672 /* rcode NOERROR */
673 if(iq->response->rep->an_numrrsets == 0) {
674 errinf(qstate, "nodata answer");
675 }
676 }
677 }
678 }
679
680 /** see if last resort is possible - does config allow queries to parent */
681 static int
can_have_last_resort(struct module_env * env,uint8_t * nm,size_t ATTR_UNUSED (nmlen),uint16_t qclass,int * have_dp,struct delegpt ** retdp,struct regional * region)682 can_have_last_resort(struct module_env* env, uint8_t* nm, size_t ATTR_UNUSED(nmlen),
683 uint16_t qclass, int* have_dp, struct delegpt** retdp,
684 struct regional* region)
685 {
686 struct delegpt* dp = NULL;
687 int nolock = 0;
688 /* do not process a last resort (the parent side) if a stub
689 * or forward is configured, because we do not want to go 'above'
690 * the configured servers */
691 if(!dname_is_root(nm) &&
692 (dp = hints_find(env->hints, nm, qclass, nolock)) &&
693 /* has_parent side is turned off for stub_first, where we
694 * are allowed to go to the parent */
695 dp->has_parent_side_NS) {
696 if(retdp) *retdp = delegpt_copy(dp, region);
697 lock_rw_unlock(&env->hints->lock);
698 if(have_dp) *have_dp = 1;
699 return 0;
700 }
701 if(dp) {
702 lock_rw_unlock(&env->hints->lock);
703 dp = NULL;
704 }
705 if((dp = forwards_find(env->fwds, nm, qclass, nolock)) &&
706 /* has_parent_side is turned off for forward_first, where
707 * we are allowed to go to the parent */
708 dp->has_parent_side_NS) {
709 if(retdp) *retdp = delegpt_copy(dp, region);
710 lock_rw_unlock(&env->fwds->lock);
711 if(have_dp) *have_dp = 1;
712 return 0;
713 }
714 /* lock_() calls are macros that could be nothing, surround in {} */
715 if(dp) { lock_rw_unlock(&env->fwds->lock); }
716 return 1;
717 }
718
719 /** see if target name is caps-for-id whitelisted */
720 static int
is_caps_whitelisted(struct iter_env * ie,struct iter_qstate * iq)721 is_caps_whitelisted(struct iter_env* ie, struct iter_qstate* iq)
722 {
723 if(!ie->caps_white) return 0; /* no whitelist, or no capsforid */
724 return name_tree_lookup(ie->caps_white, iq->qchase.qname,
725 iq->qchase.qname_len, dname_count_labels(iq->qchase.qname),
726 iq->qchase.qclass) != NULL;
727 }
728
729 /**
730 * Create target count structure for this query. This is always explicitly
731 * created for the parent query.
732 */
733 static void
target_count_create(struct iter_qstate * iq)734 target_count_create(struct iter_qstate* iq)
735 {
736 if(!iq->target_count) {
737 iq->target_count = (int*)calloc(TARGET_COUNT_MAX, sizeof(int));
738 /* if calloc fails we simply do not track this number */
739 if(iq->target_count) {
740 iq->target_count[TARGET_COUNT_REF] = 1;
741 iq->nxns_dp = (uint8_t**)calloc(1, sizeof(uint8_t*));
742 }
743 }
744 }
745
746 static void
target_count_increase(struct iter_qstate * iq,int num)747 target_count_increase(struct iter_qstate* iq, int num)
748 {
749 target_count_create(iq);
750 if(iq->target_count)
751 iq->target_count[TARGET_COUNT_QUERIES] += num;
752 iq->dp_target_count++;
753 }
754
755 static void
target_count_increase_nx(struct iter_qstate * iq,int num)756 target_count_increase_nx(struct iter_qstate* iq, int num)
757 {
758 target_count_create(iq);
759 if(iq->target_count)
760 iq->target_count[TARGET_COUNT_NX] += num;
761 }
762
763 /**
764 * Generate a subrequest.
765 * Generate a local request event. Local events are tied to this module, and
766 * have a corresponding (first tier) event that is waiting for this event to
767 * resolve to continue.
768 *
769 * @param qname The query name for this request.
770 * @param qnamelen length of qname
771 * @param qtype The query type for this request.
772 * @param qclass The query class for this request.
773 * @param qstate The event that is generating this event.
774 * @param id: module id.
775 * @param iq: The iterator state that is generating this event.
776 * @param initial_state The initial response state (normally this
777 * is QUERY_RESP_STATE, unless it is known that the request won't
778 * need iterative processing
779 * @param finalstate The final state for the response to this request.
780 * @param subq_ret: if newly allocated, the subquerystate, or NULL if it does
781 * not need initialisation.
782 * @param v: if true, validation is done on the subquery.
783 * @param detached: true if this qstate should not attach to the subquery
784 * @return false on error (malloc).
785 */
786 static int
generate_sub_request(uint8_t * qname,size_t qnamelen,uint16_t qtype,uint16_t qclass,struct module_qstate * qstate,int id,struct iter_qstate * iq,enum iter_state initial_state,enum iter_state finalstate,struct module_qstate ** subq_ret,int v,int detached)787 generate_sub_request(uint8_t* qname, size_t qnamelen, uint16_t qtype,
788 uint16_t qclass, struct module_qstate* qstate, int id,
789 struct iter_qstate* iq, enum iter_state initial_state,
790 enum iter_state finalstate, struct module_qstate** subq_ret, int v,
791 int detached)
792 {
793 struct module_qstate* subq = NULL;
794 struct iter_qstate* subiq = NULL;
795 uint16_t qflags = 0; /* OPCODE QUERY, no flags */
796 struct query_info qinf;
797 int prime = (finalstate == PRIME_RESP_STATE)?1:0;
798 int valrec = 0;
799 qinf.qname = qname;
800 qinf.qname_len = qnamelen;
801 qinf.qtype = qtype;
802 qinf.qclass = qclass;
803 qinf.local_alias = NULL;
804
805 /* RD should be set only when sending the query back through the INIT
806 * state. */
807 if(initial_state == INIT_REQUEST_STATE)
808 qflags |= BIT_RD;
809 /* We set the CD flag so we can send this through the "head" of
810 * the resolution chain, which might have a validator. We are
811 * uninterested in validating things not on the direct resolution
812 * path. */
813 if(!v) {
814 qflags |= BIT_CD;
815 valrec = 1;
816 }
817
818 if(detached) {
819 struct mesh_state* sub = NULL;
820 fptr_ok(fptr_whitelist_modenv_add_sub(
821 qstate->env->add_sub));
822 if(!(*qstate->env->add_sub)(qstate, &qinf,
823 qflags, prime, valrec, &subq, &sub)){
824 return 0;
825 }
826 }
827 else {
828 /* attach subquery, lookup existing or make a new one */
829 fptr_ok(fptr_whitelist_modenv_attach_sub(
830 qstate->env->attach_sub));
831 if(!(*qstate->env->attach_sub)(qstate, &qinf, qflags, prime,
832 valrec, &subq)) {
833 return 0;
834 }
835 }
836 *subq_ret = subq;
837 if(subq) {
838 /* initialise the new subquery */
839 subq->curmod = id;
840 subq->ext_state[id] = module_state_initial;
841 subq->minfo[id] = regional_alloc(subq->region,
842 sizeof(struct iter_qstate));
843 if(!subq->minfo[id]) {
844 log_err("init subq: out of memory");
845 fptr_ok(fptr_whitelist_modenv_kill_sub(
846 qstate->env->kill_sub));
847 (*qstate->env->kill_sub)(subq);
848 return 0;
849 }
850 subiq = (struct iter_qstate*)subq->minfo[id];
851 memset(subiq, 0, sizeof(*subiq));
852 subiq->num_target_queries = 0;
853 target_count_create(iq);
854 subiq->target_count = iq->target_count;
855 if(iq->target_count) {
856 iq->target_count[TARGET_COUNT_REF] ++; /* extra reference */
857 subiq->nxns_dp = iq->nxns_dp;
858 }
859 subiq->dp_target_count = 0;
860 subiq->num_current_queries = 0;
861 subiq->depth = iq->depth+1;
862 outbound_list_init(&subiq->outlist);
863 subiq->state = initial_state;
864 subiq->final_state = finalstate;
865 subiq->qchase = subq->qinfo;
866 subiq->chase_flags = subq->query_flags;
867 subiq->refetch_glue = 0;
868 if(qstate->env->cfg->qname_minimisation)
869 subiq->minimisation_state = INIT_MINIMISE_STATE;
870 else
871 subiq->minimisation_state = DONOT_MINIMISE_STATE;
872 memset(&subiq->qinfo_out, 0, sizeof(struct query_info));
873 }
874 return 1;
875 }
876
877 /**
878 * Generate and send a root priming request.
879 * @param qstate: the qtstate that triggered the need to prime.
880 * @param iq: iterator query state.
881 * @param id: module id.
882 * @param qclass: the class to prime.
883 * @return 0 on failure
884 */
885 static int
prime_root(struct module_qstate * qstate,struct iter_qstate * iq,int id,uint16_t qclass)886 prime_root(struct module_qstate* qstate, struct iter_qstate* iq, int id,
887 uint16_t qclass)
888 {
889 struct delegpt* dp;
890 struct module_qstate* subq;
891 int nolock = 0;
892 verbose(VERB_DETAIL, "priming . %s NS",
893 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)?
894 sldns_lookup_by_id(sldns_rr_classes, (int)qclass)->name:"??");
895 dp = hints_find_root(qstate->env->hints, qclass, nolock);
896 if(!dp) {
897 verbose(VERB_ALGO, "Cannot prime due to lack of hints");
898 return 0;
899 }
900 /* Priming requests start at the QUERYTARGETS state, skipping
901 * the normal INIT state logic (which would cause an infloop). */
902 if(!generate_sub_request((uint8_t*)"\000", 1, LDNS_RR_TYPE_NS,
903 qclass, qstate, id, iq, QUERYTARGETS_STATE, PRIME_RESP_STATE,
904 &subq, 0, 0)) {
905 lock_rw_unlock(&qstate->env->hints->lock);
906 verbose(VERB_ALGO, "could not prime root");
907 return 0;
908 }
909 if(subq) {
910 struct iter_qstate* subiq =
911 (struct iter_qstate*)subq->minfo[id];
912 /* Set the initial delegation point to the hint.
913 * copy dp, it is now part of the root prime query.
914 * dp was part of in the fixed hints structure. */
915 subiq->dp = delegpt_copy(dp, subq->region);
916 lock_rw_unlock(&qstate->env->hints->lock);
917 if(!subiq->dp) {
918 log_err("out of memory priming root, copydp");
919 fptr_ok(fptr_whitelist_modenv_kill_sub(
920 qstate->env->kill_sub));
921 (*qstate->env->kill_sub)(subq);
922 return 0;
923 }
924 /* there should not be any target queries. */
925 subiq->num_target_queries = 0;
926 subiq->dnssec_expected = iter_indicates_dnssec(
927 qstate->env, subiq->dp, NULL, subq->qinfo.qclass);
928 } else {
929 lock_rw_unlock(&qstate->env->hints->lock);
930 }
931
932 /* this module stops, our submodule starts, and does the query. */
933 qstate->ext_state[id] = module_wait_subquery;
934 return 1;
935 }
936
937 /**
938 * Generate and process a stub priming request. This method tests for the
939 * need to prime a stub zone, so it is safe to call for every request.
940 *
941 * @param qstate: the qtstate that triggered the need to prime.
942 * @param iq: iterator query state.
943 * @param id: module id.
944 * @param qname: request name.
945 * @param qclass: request class.
946 * @return true if a priming subrequest was made, false if not. The will only
947 * issue a priming request if it detects an unprimed stub.
948 * Uses value of 2 to signal during stub-prime in root-prime situation
949 * that a noprime-stub is available and resolution can continue.
950 */
951 static int
prime_stub(struct module_qstate * qstate,struct iter_qstate * iq,int id,uint8_t * qname,uint16_t qclass)952 prime_stub(struct module_qstate* qstate, struct iter_qstate* iq, int id,
953 uint8_t* qname, uint16_t qclass)
954 {
955 /* Lookup the stub hint. This will return null if the stub doesn't
956 * need to be re-primed. */
957 struct iter_hints_stub* stub;
958 struct delegpt* stub_dp;
959 struct module_qstate* subq;
960 int nolock = 0;
961
962 if(!qname) return 0;
963 stub = hints_lookup_stub(qstate->env->hints, qname, qclass, iq->dp,
964 nolock);
965 /* The stub (if there is one) does not need priming. */
966 if(!stub) return 0;
967 stub_dp = stub->dp;
968 /* if we have an auth_zone dp, and stub is equal, don't prime stub
969 * yet, unless we want to fallback and avoid the auth_zone */
970 if(!iq->auth_zone_avoid && iq->dp && iq->dp->auth_dp &&
971 query_dname_compare(iq->dp->name, stub_dp->name) == 0) {
972 lock_rw_unlock(&qstate->env->hints->lock);
973 return 0;
974 }
975
976 /* is it a noprime stub (always use) */
977 if(stub->noprime) {
978 int r = 0;
979 if(iq->dp == NULL) r = 2;
980 /* copy the dp out of the fixed hints structure, so that
981 * it can be changed when servicing this query */
982 iq->dp = delegpt_copy(stub_dp, qstate->region);
983 lock_rw_unlock(&qstate->env->hints->lock);
984 if(!iq->dp) {
985 log_err("out of memory priming stub");
986 errinf(qstate, "malloc failure, priming stub");
987 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
988 return 1; /* return 1 to make module stop, with error */
989 }
990 log_nametypeclass(VERB_DETAIL, "use stub", iq->dp->name,
991 LDNS_RR_TYPE_NS, qclass);
992 return r;
993 }
994
995 /* Otherwise, we need to (re)prime the stub. */
996 log_nametypeclass(VERB_DETAIL, "priming stub", stub_dp->name,
997 LDNS_RR_TYPE_NS, qclass);
998
999 /* Stub priming events start at the QUERYTARGETS state to avoid the
1000 * redundant INIT state processing. */
1001 if(!generate_sub_request(stub_dp->name, stub_dp->namelen,
1002 LDNS_RR_TYPE_NS, qclass, qstate, id, iq,
1003 QUERYTARGETS_STATE, PRIME_RESP_STATE, &subq, 0, 0)) {
1004 lock_rw_unlock(&qstate->env->hints->lock);
1005 verbose(VERB_ALGO, "could not prime stub");
1006 errinf(qstate, "could not generate lookup for stub prime");
1007 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1008 return 1; /* return 1 to make module stop, with error */
1009 }
1010 if(subq) {
1011 struct iter_qstate* subiq =
1012 (struct iter_qstate*)subq->minfo[id];
1013
1014 /* Set the initial delegation point to the hint. */
1015 /* make copy to avoid use of stub dp by different qs/threads */
1016 subiq->dp = delegpt_copy(stub_dp, subq->region);
1017 lock_rw_unlock(&qstate->env->hints->lock);
1018 if(!subiq->dp) {
1019 log_err("out of memory priming stub, copydp");
1020 fptr_ok(fptr_whitelist_modenv_kill_sub(
1021 qstate->env->kill_sub));
1022 (*qstate->env->kill_sub)(subq);
1023 errinf(qstate, "malloc failure, in stub prime");
1024 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1025 return 1; /* return 1 to make module stop, with error */
1026 }
1027 /* there should not be any target queries -- although there
1028 * wouldn't be anyway, since stub hints never have
1029 * missing targets. */
1030 subiq->num_target_queries = 0;
1031 subiq->wait_priming_stub = 1;
1032 subiq->dnssec_expected = iter_indicates_dnssec(
1033 qstate->env, subiq->dp, NULL, subq->qinfo.qclass);
1034 } else {
1035 lock_rw_unlock(&qstate->env->hints->lock);
1036 }
1037
1038 /* this module stops, our submodule starts, and does the query. */
1039 qstate->ext_state[id] = module_wait_subquery;
1040 return 1;
1041 }
1042
1043 /**
1044 * Generate a delegation point for an auth zone (unless cached dp is better)
1045 * false on alloc failure.
1046 */
1047 static int
auth_zone_delegpt(struct module_qstate * qstate,struct iter_qstate * iq,uint8_t * delname,size_t delnamelen)1048 auth_zone_delegpt(struct module_qstate* qstate, struct iter_qstate* iq,
1049 uint8_t* delname, size_t delnamelen)
1050 {
1051 struct auth_zone* z;
1052 if(iq->auth_zone_avoid)
1053 return 1;
1054 if(!delname) {
1055 delname = iq->qchase.qname;
1056 delnamelen = iq->qchase.qname_len;
1057 }
1058 lock_rw_rdlock(&qstate->env->auth_zones->lock);
1059 z = auth_zones_find_zone(qstate->env->auth_zones, delname, delnamelen,
1060 qstate->qinfo.qclass);
1061 if(!z) {
1062 lock_rw_unlock(&qstate->env->auth_zones->lock);
1063 return 1;
1064 }
1065 lock_rw_rdlock(&z->lock);
1066 lock_rw_unlock(&qstate->env->auth_zones->lock);
1067 if(z->for_upstream) {
1068 if(iq->dp && query_dname_compare(z->name, iq->dp->name) == 0
1069 && iq->dp->auth_dp && qstate->blacklist &&
1070 z->fallback_enabled) {
1071 /* cache is blacklisted and fallback, and we
1072 * already have an auth_zone dp */
1073 if(verbosity>=VERB_ALGO) {
1074 char buf[255+1];
1075 dname_str(z->name, buf);
1076 verbose(VERB_ALGO, "auth_zone %s "
1077 "fallback because cache blacklisted",
1078 buf);
1079 }
1080 lock_rw_unlock(&z->lock);
1081 iq->dp = NULL;
1082 return 1;
1083 }
1084 if(iq->dp==NULL || dname_subdomain_c(z->name, iq->dp->name)) {
1085 struct delegpt* dp;
1086 if(qstate->blacklist && z->fallback_enabled) {
1087 /* cache is blacklisted because of a DNSSEC
1088 * validation failure, and the zone allows
1089 * fallback to the internet, query there. */
1090 if(verbosity>=VERB_ALGO) {
1091 char buf[255+1];
1092 dname_str(z->name, buf);
1093 verbose(VERB_ALGO, "auth_zone %s "
1094 "fallback because cache blacklisted",
1095 buf);
1096 }
1097 lock_rw_unlock(&z->lock);
1098 return 1;
1099 }
1100 dp = (struct delegpt*)regional_alloc_zero(
1101 qstate->region, sizeof(*dp));
1102 if(!dp) {
1103 log_err("alloc failure");
1104 if(z->fallback_enabled) {
1105 lock_rw_unlock(&z->lock);
1106 return 1; /* just fallback */
1107 }
1108 lock_rw_unlock(&z->lock);
1109 errinf(qstate, "malloc failure");
1110 return 0;
1111 }
1112 dp->name = regional_alloc_init(qstate->region,
1113 z->name, z->namelen);
1114 if(!dp->name) {
1115 log_err("alloc failure");
1116 if(z->fallback_enabled) {
1117 lock_rw_unlock(&z->lock);
1118 return 1; /* just fallback */
1119 }
1120 lock_rw_unlock(&z->lock);
1121 errinf(qstate, "malloc failure");
1122 return 0;
1123 }
1124 dp->namelen = z->namelen;
1125 dp->namelabs = z->namelabs;
1126 dp->auth_dp = 1;
1127 iq->dp = dp;
1128 }
1129 }
1130
1131 lock_rw_unlock(&z->lock);
1132 return 1;
1133 }
1134
1135 /**
1136 * Generate A and AAAA checks for glue that is in-zone for the referral
1137 * we just got to obtain authoritative information on the addresses.
1138 *
1139 * @param qstate: the qtstate that triggered the need to prime.
1140 * @param iq: iterator query state.
1141 * @param id: module id.
1142 */
1143 static void
generate_a_aaaa_check(struct module_qstate * qstate,struct iter_qstate * iq,int id)1144 generate_a_aaaa_check(struct module_qstate* qstate, struct iter_qstate* iq,
1145 int id)
1146 {
1147 struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
1148 struct module_qstate* subq;
1149 size_t i;
1150 struct reply_info* rep = iq->response->rep;
1151 struct ub_packed_rrset_key* s;
1152 log_assert(iq->dp);
1153
1154 if(iq->depth == ie->max_dependency_depth)
1155 return;
1156 /* walk through additional, and check if in-zone,
1157 * only relevant A, AAAA are left after scrub anyway */
1158 for(i=rep->an_numrrsets+rep->ns_numrrsets; i<rep->rrset_count; i++) {
1159 s = rep->rrsets[i];
1160 /* check *ALL* addresses that are transmitted in additional*/
1161 /* is it an address ? */
1162 if( !(ntohs(s->rk.type)==LDNS_RR_TYPE_A ||
1163 ntohs(s->rk.type)==LDNS_RR_TYPE_AAAA)) {
1164 continue;
1165 }
1166 /* is this query the same as the A/AAAA check for it */
1167 if(qstate->qinfo.qtype == ntohs(s->rk.type) &&
1168 qstate->qinfo.qclass == ntohs(s->rk.rrset_class) &&
1169 query_dname_compare(qstate->qinfo.qname,
1170 s->rk.dname)==0 &&
1171 (qstate->query_flags&BIT_RD) &&
1172 !(qstate->query_flags&BIT_CD))
1173 continue;
1174
1175 /* generate subrequest for it */
1176 log_nametypeclass(VERB_ALGO, "schedule addr fetch",
1177 s->rk.dname, ntohs(s->rk.type),
1178 ntohs(s->rk.rrset_class));
1179 if(!generate_sub_request(s->rk.dname, s->rk.dname_len,
1180 ntohs(s->rk.type), ntohs(s->rk.rrset_class),
1181 qstate, id, iq,
1182 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1, 0)) {
1183 verbose(VERB_ALGO, "could not generate addr check");
1184 return;
1185 }
1186 /* ignore subq - not need for more init */
1187 }
1188 }
1189
1190 /**
1191 * Generate a NS check request to obtain authoritative information
1192 * on an NS rrset.
1193 *
1194 * @param qstate: the qstate that triggered the need to prime.
1195 * @param iq: iterator query state.
1196 * @param id: module id.
1197 */
1198 static void
generate_ns_check(struct module_qstate * qstate,struct iter_qstate * iq,int id)1199 generate_ns_check(struct module_qstate* qstate, struct iter_qstate* iq, int id)
1200 {
1201 struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
1202 struct module_qstate* subq;
1203 log_assert(iq->dp);
1204
1205 if(iq->depth == ie->max_dependency_depth)
1206 return;
1207 if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen,
1208 iq->qchase.qclass, NULL, NULL, NULL))
1209 return;
1210 /* is this query the same as the nscheck? */
1211 if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS &&
1212 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 &&
1213 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){
1214 /* spawn off A, AAAA queries for in-zone glue to check */
1215 generate_a_aaaa_check(qstate, iq, id);
1216 return;
1217 }
1218 /* no need to get the NS record for DS, it is above the zonecut */
1219 if(qstate->qinfo.qtype == LDNS_RR_TYPE_DS)
1220 return;
1221
1222 log_nametypeclass(VERB_ALGO, "schedule ns fetch",
1223 iq->dp->name, LDNS_RR_TYPE_NS, iq->qchase.qclass);
1224 if(!generate_sub_request(iq->dp->name, iq->dp->namelen,
1225 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
1226 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1, 0)) {
1227 verbose(VERB_ALGO, "could not generate ns check");
1228 return;
1229 }
1230 if(subq) {
1231 struct iter_qstate* subiq =
1232 (struct iter_qstate*)subq->minfo[id];
1233
1234 /* make copy to avoid use of stub dp by different qs/threads */
1235 /* refetch glue to start higher up the tree */
1236 subiq->refetch_glue = 1;
1237 subiq->dp = delegpt_copy(iq->dp, subq->region);
1238 if(!subiq->dp) {
1239 log_err("out of memory generating ns check, copydp");
1240 fptr_ok(fptr_whitelist_modenv_kill_sub(
1241 qstate->env->kill_sub));
1242 (*qstate->env->kill_sub)(subq);
1243 return;
1244 }
1245 }
1246 }
1247
1248 /**
1249 * Generate a DNSKEY prefetch query to get the DNSKEY for the DS record we
1250 * just got in a referral (where we have dnssec_expected, thus have trust
1251 * anchors above it). Note that right after calling this routine the
1252 * iterator detached subqueries (because of following the referral), and thus
1253 * the DNSKEY query becomes detached, its return stored in the cache for
1254 * later lookup by the validator. This cache lookup by the validator avoids
1255 * the roundtrip incurred by the DNSKEY query. The DNSKEY query is now
1256 * performed at about the same time the original query is sent to the domain,
1257 * thus the two answers are likely to be returned at about the same time,
1258 * saving a roundtrip from the validated lookup.
1259 *
1260 * @param qstate: the qtstate that triggered the need to prime.
1261 * @param iq: iterator query state.
1262 * @param id: module id.
1263 */
1264 static void
generate_dnskey_prefetch(struct module_qstate * qstate,struct iter_qstate * iq,int id)1265 generate_dnskey_prefetch(struct module_qstate* qstate,
1266 struct iter_qstate* iq, int id)
1267 {
1268 struct module_qstate* subq;
1269 log_assert(iq->dp);
1270
1271 /* is this query the same as the prefetch? */
1272 if(qstate->qinfo.qtype == LDNS_RR_TYPE_DNSKEY &&
1273 query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 &&
1274 (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){
1275 return;
1276 }
1277 /* we do not generate this prefetch when the query list is full,
1278 * the query is fetched, if needed, when the validator wants it.
1279 * At that time the validator waits for it, after spawning it.
1280 * This means there is one state that uses cpu and a socket, the
1281 * spawned while this one waits, and not several at the same time,
1282 * if we had created the lookup here. And this helps to keep
1283 * the total load down, but the query still succeeds to resolve. */
1284 if(mesh_jostle_exceeded(qstate->env->mesh))
1285 return;
1286
1287 /* if the DNSKEY is in the cache this lookup will stop quickly */
1288 log_nametypeclass(VERB_ALGO, "schedule dnskey prefetch",
1289 iq->dp->name, LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass);
1290 if(!generate_sub_request(iq->dp->name, iq->dp->namelen,
1291 LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass, qstate, id, iq,
1292 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0)) {
1293 /* we'll be slower, but it'll work */
1294 verbose(VERB_ALGO, "could not generate dnskey prefetch");
1295 return;
1296 }
1297 if(subq) {
1298 struct iter_qstate* subiq =
1299 (struct iter_qstate*)subq->minfo[id];
1300 /* this qstate has the right delegation for the dnskey lookup*/
1301 /* make copy to avoid use of stub dp by different qs/threads */
1302 subiq->dp = delegpt_copy(iq->dp, subq->region);
1303 /* if !subiq->dp, it'll start from the cache, no problem */
1304 }
1305 }
1306
1307 /**
1308 * See if the query needs forwarding.
1309 *
1310 * @param qstate: query state.
1311 * @param iq: iterator query state.
1312 * @return true if the request is forwarded, false if not.
1313 * If returns true but, iq->dp is NULL then a malloc failure occurred.
1314 */
1315 static int
forward_request(struct module_qstate * qstate,struct iter_qstate * iq)1316 forward_request(struct module_qstate* qstate, struct iter_qstate* iq)
1317 {
1318 struct delegpt* dp;
1319 uint8_t* delname = iq->qchase.qname;
1320 size_t delnamelen = iq->qchase.qname_len;
1321 int nolock = 0;
1322 if(iq->refetch_glue && iq->dp) {
1323 delname = iq->dp->name;
1324 delnamelen = iq->dp->namelen;
1325 }
1326 /* strip one label off of DS query to lookup higher for it */
1327 if( (iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue)
1328 && !dname_is_root(iq->qchase.qname))
1329 dname_remove_label(&delname, &delnamelen);
1330 dp = forwards_lookup(qstate->env->fwds, delname, iq->qchase.qclass,
1331 nolock);
1332 if(!dp) return 0;
1333 /* send recursion desired to forward addr */
1334 iq->chase_flags |= BIT_RD;
1335 iq->dp = delegpt_copy(dp, qstate->region);
1336 lock_rw_unlock(&qstate->env->fwds->lock);
1337 /* iq->dp checked by caller */
1338 verbose(VERB_ALGO, "forwarding request");
1339 return 1;
1340 }
1341
1342 /**
1343 * Process the initial part of the request handling. This state roughly
1344 * corresponds to resolver algorithms steps 1 (find answer in cache) and 2
1345 * (find the best servers to ask).
1346 *
1347 * Note that all requests start here, and query restarts revisit this state.
1348 *
1349 * This state either generates: 1) a response, from cache or error, 2) a
1350 * priming event, or 3) forwards the request to the next state (init2,
1351 * generally).
1352 *
1353 * @param qstate: query state.
1354 * @param iq: iterator query state.
1355 * @param ie: iterator shared global environment.
1356 * @param id: module id.
1357 * @return true if the event needs more request processing immediately,
1358 * false if not.
1359 */
1360 static int
processInitRequest(struct module_qstate * qstate,struct iter_qstate * iq,struct iter_env * ie,int id)1361 processInitRequest(struct module_qstate* qstate, struct iter_qstate* iq,
1362 struct iter_env* ie, int id)
1363 {
1364 uint8_t dpname_storage[LDNS_MAX_DOMAINLEN+1];
1365 uint8_t* delname, *dpname=NULL;
1366 size_t delnamelen, dpnamelen=0;
1367 struct dns_msg* msg = NULL;
1368
1369 log_query_info(VERB_DETAIL, "resolving", &qstate->qinfo);
1370 /* check effort */
1371
1372 /* We enforce a maximum number of query restarts. This is primarily a
1373 * cheap way to prevent CNAME loops. */
1374 if(iq->query_restart_count > ie->max_query_restarts) {
1375 verbose(VERB_QUERY, "request has exceeded the maximum number"
1376 " of query restarts with %d", iq->query_restart_count);
1377 errinf(qstate, "request has exceeded the maximum number "
1378 "restarts (eg. indirections)");
1379 if(iq->qchase.qname)
1380 errinf_dname(qstate, "stop at", iq->qchase.qname);
1381 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1382 }
1383
1384 /* We enforce a maximum recursion/dependency depth -- in general,
1385 * this is unnecessary for dependency loops (although it will
1386 * catch those), but it provides a sensible limit to the amount
1387 * of work required to answer a given query. */
1388 verbose(VERB_ALGO, "request has dependency depth of %d", iq->depth);
1389 if(iq->depth > ie->max_dependency_depth) {
1390 verbose(VERB_QUERY, "request has exceeded the maximum "
1391 "dependency depth with depth of %d", iq->depth);
1392 errinf(qstate, "request has exceeded the maximum dependency "
1393 "depth (eg. nameserver lookup recursion)");
1394 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1395 }
1396
1397 /* If the request is qclass=ANY, setup to generate each class */
1398 if(qstate->qinfo.qclass == LDNS_RR_CLASS_ANY) {
1399 iq->qchase.qclass = 0;
1400 return next_state(iq, COLLECT_CLASS_STATE);
1401 }
1402
1403 /*
1404 * If we are restricted by a forward-zone or a stub-zone, we
1405 * can't re-fetch glue for this delegation point.
1406 * we won’t try to re-fetch glue if the iq->dp is null.
1407 */
1408 if (iq->refetch_glue &&
1409 iq->dp &&
1410 !can_have_last_resort(qstate->env, iq->dp->name,
1411 iq->dp->namelen, iq->qchase.qclass, NULL, NULL, NULL)) {
1412 iq->refetch_glue = 0;
1413 }
1414
1415 /* Resolver Algorithm Step 1 -- Look for the answer in local data. */
1416
1417 /* This either results in a query restart (CNAME cache response), a
1418 * terminating response (ANSWER), or a cache miss (null). */
1419
1420 /* Check RPZ for override */
1421 if(qstate->env->auth_zones) {
1422 /* apply rpz qname triggers, like after cname */
1423 struct dns_msg* forged_response =
1424 rpz_callback_from_iterator_cname(qstate, iq);
1425 if(forged_response) {
1426 uint8_t* sname = 0;
1427 size_t slen = 0;
1428 int count = 0;
1429 while(forged_response && reply_find_rrset_section_an(
1430 forged_response->rep, iq->qchase.qname,
1431 iq->qchase.qname_len, LDNS_RR_TYPE_CNAME,
1432 iq->qchase.qclass) &&
1433 iq->qchase.qtype != LDNS_RR_TYPE_CNAME &&
1434 count++ < ie->max_query_restarts) {
1435 /* another cname to follow */
1436 if(!handle_cname_response(qstate, iq, forged_response,
1437 &sname, &slen)) {
1438 errinf(qstate, "malloc failure, CNAME info");
1439 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1440 }
1441 iq->qchase.qname = sname;
1442 iq->qchase.qname_len = slen;
1443 forged_response =
1444 rpz_callback_from_iterator_cname(qstate, iq);
1445 }
1446 if(forged_response != NULL) {
1447 qstate->ext_state[id] = module_finished;
1448 qstate->return_rcode = LDNS_RCODE_NOERROR;
1449 qstate->return_msg = forged_response;
1450 iq->response = forged_response;
1451 next_state(iq, FINISHED_STATE);
1452 if(!iter_prepend(iq, qstate->return_msg, qstate->region)) {
1453 log_err("rpz: after cached cname, prepend rrsets: out of memory");
1454 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1455 }
1456 qstate->return_msg->qinfo = qstate->qinfo;
1457 return 0;
1458 }
1459 /* Follow the CNAME response */
1460 iq->dp = NULL;
1461 iq->refetch_glue = 0;
1462 iq->query_restart_count++;
1463 iq->sent_count = 0;
1464 iq->dp_target_count = 0;
1465 sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1466 if(qstate->env->cfg->qname_minimisation)
1467 iq->minimisation_state = INIT_MINIMISE_STATE;
1468 return next_state(iq, INIT_REQUEST_STATE);
1469 }
1470 }
1471
1472 if (iter_stub_fwd_no_cache(qstate, &iq->qchase, &dpname, &dpnamelen,
1473 dpname_storage, sizeof(dpname_storage))) {
1474 /* Asked to not query cache. */
1475 verbose(VERB_ALGO, "no-cache set, going to the network");
1476 qstate->no_cache_lookup = 1;
1477 qstate->no_cache_store = 1;
1478 msg = NULL;
1479 } else if(qstate->blacklist) {
1480 /* if cache, or anything else, was blacklisted then
1481 * getting older results from cache is a bad idea, no cache */
1482 verbose(VERB_ALGO, "cache blacklisted, going to the network");
1483 msg = NULL;
1484 } else if(!qstate->no_cache_lookup) {
1485 msg = dns_cache_lookup(qstate->env, iq->qchase.qname,
1486 iq->qchase.qname_len, iq->qchase.qtype,
1487 iq->qchase.qclass, qstate->query_flags,
1488 qstate->region, qstate->env->scratch, 0, dpname,
1489 dpnamelen);
1490 if(!msg && qstate->env->neg_cache &&
1491 iter_qname_indicates_dnssec(qstate->env, &iq->qchase)) {
1492 /* lookup in negative cache; may result in
1493 * NOERROR/NODATA or NXDOMAIN answers that need validation */
1494 msg = val_neg_getmsg(qstate->env->neg_cache, &iq->qchase,
1495 qstate->region, qstate->env->rrset_cache,
1496 qstate->env->scratch_buffer,
1497 *qstate->env->now, 1/*add SOA*/, NULL,
1498 qstate->env->cfg);
1499 }
1500 /* item taken from cache does not match our query name, thus
1501 * security needs to be re-examined later */
1502 if(msg && query_dname_compare(qstate->qinfo.qname,
1503 iq->qchase.qname) != 0)
1504 msg->rep->security = sec_status_unchecked;
1505 }
1506 if(msg) {
1507 /* handle positive cache response */
1508 enum response_type type = response_type_from_cache(msg,
1509 &iq->qchase);
1510 if(verbosity >= VERB_ALGO) {
1511 log_dns_msg("msg from cache lookup", &msg->qinfo,
1512 msg->rep);
1513 verbose(VERB_ALGO, "msg ttl is %d, prefetch ttl %d",
1514 (int)msg->rep->ttl,
1515 (int)msg->rep->prefetch_ttl);
1516 }
1517
1518 if(type == RESPONSE_TYPE_CNAME) {
1519 uint8_t* sname = 0;
1520 size_t slen = 0;
1521 verbose(VERB_ALGO, "returning CNAME response from "
1522 "cache");
1523 if(!handle_cname_response(qstate, iq, msg,
1524 &sname, &slen)) {
1525 errinf(qstate, "failed to prepend CNAME "
1526 "components, malloc failure");
1527 return error_response(qstate, id,
1528 LDNS_RCODE_SERVFAIL);
1529 }
1530 iq->qchase.qname = sname;
1531 iq->qchase.qname_len = slen;
1532 /* This *is* a query restart, even if it is a cheap
1533 * one. */
1534 iq->dp = NULL;
1535 iq->refetch_glue = 0;
1536 iq->query_restart_count++;
1537 iq->sent_count = 0;
1538 iq->dp_target_count = 0;
1539 sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1540 if(qstate->env->cfg->qname_minimisation)
1541 iq->minimisation_state = INIT_MINIMISE_STATE;
1542 return next_state(iq, INIT_REQUEST_STATE);
1543 }
1544 /* if from cache, NULL, else insert 'cache IP' len=0 */
1545 if(qstate->reply_origin)
1546 sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1547 if(FLAGS_GET_RCODE(msg->rep->flags) == LDNS_RCODE_SERVFAIL)
1548 errinf(qstate, "SERVFAIL in cache");
1549 /* it is an answer, response, to final state */
1550 verbose(VERB_ALGO, "returning answer from cache.");
1551 iq->response = msg;
1552 return final_state(iq);
1553 }
1554
1555 /* attempt to forward the request */
1556 if(forward_request(qstate, iq))
1557 {
1558 if(!iq->dp) {
1559 log_err("alloc failure for forward dp");
1560 errinf(qstate, "malloc failure for forward zone");
1561 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1562 }
1563 if((qstate->query_flags&BIT_RD)==0) {
1564 /* If the server accepts RD=0 queries and forwards
1565 * with RD=1, then if the server is listed as an NS
1566 * entry, it starts query loops. Stop that loop by
1567 * disallowing the query. The RD=0 was previously used
1568 * to check the cache with allow_snoop. For stubs,
1569 * the iterator pass would have primed the stub and
1570 * then cached information can be used for further
1571 * queries. */
1572 verbose(VERB_ALGO, "cannot forward RD=0 query, to stop query loops");
1573 errinf(qstate, "cannot forward RD=0 query");
1574 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1575 }
1576 iq->refetch_glue = 0;
1577 iq->minimisation_state = DONOT_MINIMISE_STATE;
1578 /* the request has been forwarded.
1579 * forwarded requests need to be immediately sent to the
1580 * next state, QUERYTARGETS. */
1581 return next_state(iq, QUERYTARGETS_STATE);
1582 }
1583
1584 /* Resolver Algorithm Step 2 -- find the "best" servers. */
1585
1586 /* first, adjust for DS queries. To avoid the grandparent problem,
1587 * we just look for the closest set of server to the parent of qname.
1588 * When re-fetching glue we also need to ask the parent.
1589 */
1590 if(iq->refetch_glue) {
1591 if(!iq->dp) {
1592 log_err("internal or malloc fail: no dp for refetch");
1593 errinf(qstate, "malloc failure, for delegation info");
1594 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1595 }
1596 delname = iq->dp->name;
1597 delnamelen = iq->dp->namelen;
1598 } else {
1599 delname = iq->qchase.qname;
1600 delnamelen = iq->qchase.qname_len;
1601 }
1602 if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue ||
1603 (iq->qchase.qtype == LDNS_RR_TYPE_NS && qstate->prefetch_leeway
1604 && can_have_last_resort(qstate->env, delname, delnamelen, iq->qchase.qclass, NULL, NULL, NULL))) {
1605 /* remove first label from delname, root goes to hints,
1606 * but only to fetch glue, not for qtype=DS. */
1607 /* also when prefetching an NS record, fetch it again from
1608 * its parent, just as if it expired, so that you do not
1609 * get stuck on an older nameserver that gives old NSrecords */
1610 if(dname_is_root(delname) && (iq->refetch_glue ||
1611 (iq->qchase.qtype == LDNS_RR_TYPE_NS &&
1612 qstate->prefetch_leeway)))
1613 delname = NULL; /* go to root priming */
1614 else dname_remove_label(&delname, &delnamelen);
1615 }
1616 /* delname is the name to lookup a delegation for. If NULL rootprime */
1617 while(1) {
1618
1619 /* Lookup the delegation in the cache. If null, then the
1620 * cache needs to be primed for the qclass. */
1621 if(delname)
1622 iq->dp = dns_cache_find_delegation(qstate->env, delname,
1623 delnamelen, iq->qchase.qtype, iq->qchase.qclass,
1624 qstate->region, &iq->deleg_msg,
1625 *qstate->env->now+qstate->prefetch_leeway, 1,
1626 dpname, dpnamelen);
1627 else iq->dp = NULL;
1628
1629 /* If the cache has returned nothing, then we have a
1630 * root priming situation. */
1631 if(iq->dp == NULL) {
1632 int r;
1633 int nolock = 0;
1634 /* if under auth zone, no prime needed */
1635 if(!auth_zone_delegpt(qstate, iq, delname, delnamelen))
1636 return error_response(qstate, id,
1637 LDNS_RCODE_SERVFAIL);
1638 if(iq->dp) /* use auth zone dp */
1639 return next_state(iq, INIT_REQUEST_2_STATE);
1640 /* if there is a stub, then no root prime needed */
1641 r = prime_stub(qstate, iq, id, delname,
1642 iq->qchase.qclass);
1643 if(r == 2)
1644 break; /* got noprime-stub-zone, continue */
1645 else if(r)
1646 return 0; /* stub prime request made */
1647 if(forwards_lookup_root(qstate->env->fwds,
1648 iq->qchase.qclass, nolock)) {
1649 lock_rw_unlock(&qstate->env->fwds->lock);
1650 /* forward zone root, no root prime needed */
1651 /* fill in some dp - safety belt */
1652 iq->dp = hints_find_root(qstate->env->hints,
1653 iq->qchase.qclass, nolock);
1654 if(!iq->dp) {
1655 log_err("internal error: no hints dp");
1656 errinf(qstate, "no hints for this class");
1657 return error_response(qstate, id,
1658 LDNS_RCODE_SERVFAIL);
1659 }
1660 iq->dp = delegpt_copy(iq->dp, qstate->region);
1661 lock_rw_unlock(&qstate->env->hints->lock);
1662 if(!iq->dp) {
1663 log_err("out of memory in safety belt");
1664 errinf(qstate, "malloc failure, in safety belt");
1665 return error_response(qstate, id,
1666 LDNS_RCODE_SERVFAIL);
1667 }
1668 return next_state(iq, INIT_REQUEST_2_STATE);
1669 }
1670 /* Note that the result of this will set a new
1671 * DelegationPoint based on the result of priming. */
1672 if(!prime_root(qstate, iq, id, iq->qchase.qclass))
1673 return error_response(qstate, id,
1674 LDNS_RCODE_REFUSED);
1675
1676 /* priming creates and sends a subordinate query, with
1677 * this query as the parent. So further processing for
1678 * this event will stop until reactivated by the
1679 * results of priming. */
1680 return 0;
1681 }
1682 if(!iq->ratelimit_ok && qstate->prefetch_leeway)
1683 iq->ratelimit_ok = 1; /* allow prefetches, this keeps
1684 otherwise valid data in the cache */
1685
1686 /* see if this dp not useless.
1687 * It is useless if:
1688 * o all NS items are required glue.
1689 * or the query is for NS item that is required glue.
1690 * o no addresses are provided.
1691 * o RD qflag is on.
1692 * Instead, go up one level, and try to get even further
1693 * If the root was useless, use safety belt information.
1694 * Only check cache returns, because replies for servers
1695 * could be useless but lead to loops (bumping into the
1696 * same server reply) if useless-checked.
1697 */
1698 if(iter_dp_is_useless(&qstate->qinfo, qstate->query_flags,
1699 iq->dp, ie->supports_ipv4, ie->supports_ipv6,
1700 ie->use_nat64)) {
1701 int have_dp = 0;
1702 if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen, iq->qchase.qclass, &have_dp, &iq->dp, qstate->region)) {
1703 if(have_dp) {
1704 verbose(VERB_QUERY, "cache has stub "
1705 "or fwd but no addresses, "
1706 "fallback to config");
1707 if(have_dp && !iq->dp) {
1708 log_err("out of memory in "
1709 "stub/fwd fallback");
1710 errinf(qstate, "malloc failure, for fallback to config");
1711 return error_response(qstate,
1712 id, LDNS_RCODE_SERVFAIL);
1713 }
1714 break;
1715 }
1716 verbose(VERB_ALGO, "useless dp "
1717 "but cannot go up, servfail");
1718 delegpt_log(VERB_ALGO, iq->dp);
1719 errinf(qstate, "no useful nameservers, "
1720 "and cannot go up");
1721 errinf_dname(qstate, "for zone", iq->dp->name);
1722 return error_response(qstate, id,
1723 LDNS_RCODE_SERVFAIL);
1724 }
1725 if(dname_is_root(iq->dp->name)) {
1726 /* use safety belt */
1727 int nolock = 0;
1728 verbose(VERB_QUERY, "Cache has root NS but "
1729 "no addresses. Fallback to the safety belt.");
1730 iq->dp = hints_find_root(qstate->env->hints,
1731 iq->qchase.qclass, nolock);
1732 /* note deleg_msg is from previous lookup,
1733 * but RD is on, so it is not used */
1734 if(!iq->dp) {
1735 log_err("internal error: no hints dp");
1736 return error_response(qstate, id,
1737 LDNS_RCODE_REFUSED);
1738 }
1739 iq->dp = delegpt_copy(iq->dp, qstate->region);
1740 lock_rw_unlock(&qstate->env->hints->lock);
1741 if(!iq->dp) {
1742 log_err("out of memory in safety belt");
1743 errinf(qstate, "malloc failure, in safety belt, for root");
1744 return error_response(qstate, id,
1745 LDNS_RCODE_SERVFAIL);
1746 }
1747 break;
1748 } else {
1749 verbose(VERB_ALGO,
1750 "cache delegation was useless:");
1751 delegpt_log(VERB_ALGO, iq->dp);
1752 /* go up */
1753 delname = iq->dp->name;
1754 delnamelen = iq->dp->namelen;
1755 dname_remove_label(&delname, &delnamelen);
1756 }
1757 } else break;
1758 }
1759
1760 verbose(VERB_ALGO, "cache delegation returns delegpt");
1761 delegpt_log(VERB_ALGO, iq->dp);
1762
1763 /* Otherwise, set the current delegation point and move on to the
1764 * next state. */
1765 return next_state(iq, INIT_REQUEST_2_STATE);
1766 }
1767
1768 /**
1769 * Process the second part of the initial request handling. This state
1770 * basically exists so that queries that generate root priming events have
1771 * the same init processing as ones that do not. Request events that reach
1772 * this state must have a valid currentDelegationPoint set.
1773 *
1774 * This part is primarily handling stub zone priming. Events that reach this
1775 * state must have a current delegation point.
1776 *
1777 * @param qstate: query state.
1778 * @param iq: iterator query state.
1779 * @param id: module id.
1780 * @return true if the event needs more request processing immediately,
1781 * false if not.
1782 */
1783 static int
processInitRequest2(struct module_qstate * qstate,struct iter_qstate * iq,int id)1784 processInitRequest2(struct module_qstate* qstate, struct iter_qstate* iq,
1785 int id)
1786 {
1787 uint8_t* delname;
1788 size_t delnamelen;
1789 log_query_info(VERB_QUERY, "resolving (init part 2): ",
1790 &qstate->qinfo);
1791
1792 delname = iq->qchase.qname;
1793 delnamelen = iq->qchase.qname_len;
1794 if(iq->refetch_glue) {
1795 struct iter_hints_stub* stub;
1796 int nolock = 0;
1797 if(!iq->dp) {
1798 log_err("internal or malloc fail: no dp for refetch");
1799 errinf(qstate, "malloc failure, no delegation info");
1800 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1801 }
1802 /* Do not send queries above stub, do not set delname to dp if
1803 * this is above stub without stub-first. */
1804 stub = hints_lookup_stub(
1805 qstate->env->hints, iq->qchase.qname, iq->qchase.qclass,
1806 iq->dp, nolock);
1807 if(!stub || !stub->dp->has_parent_side_NS ||
1808 dname_subdomain_c(iq->dp->name, stub->dp->name)) {
1809 delname = iq->dp->name;
1810 delnamelen = iq->dp->namelen;
1811 }
1812 /* lock_() calls are macros that could be nothing, surround in {} */
1813 if(stub) { lock_rw_unlock(&qstate->env->hints->lock); }
1814 }
1815 if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue) {
1816 if(!dname_is_root(delname))
1817 dname_remove_label(&delname, &delnamelen);
1818 iq->refetch_glue = 0; /* if CNAME causes restart, no refetch */
1819 }
1820
1821 /* see if we have an auth zone to answer from, improves dp from cache
1822 * (if any dp from cache) with auth zone dp, if that is lower */
1823 if(!auth_zone_delegpt(qstate, iq, delname, delnamelen))
1824 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
1825
1826 /* Check to see if we need to prime a stub zone. */
1827 if(prime_stub(qstate, iq, id, delname, iq->qchase.qclass)) {
1828 /* A priming sub request was made */
1829 return 0;
1830 }
1831
1832 /* most events just get forwarded to the next state. */
1833 return next_state(iq, INIT_REQUEST_3_STATE);
1834 }
1835
1836 /**
1837 * Process the third part of the initial request handling. This state exists
1838 * as a separate state so that queries that generate stub priming events
1839 * will get the tail end of the init process but not repeat the stub priming
1840 * check.
1841 *
1842 * @param qstate: query state.
1843 * @param iq: iterator query state.
1844 * @param id: module id.
1845 * @return true, advancing the event to the QUERYTARGETS_STATE.
1846 */
1847 static int
processInitRequest3(struct module_qstate * qstate,struct iter_qstate * iq,int id)1848 processInitRequest3(struct module_qstate* qstate, struct iter_qstate* iq,
1849 int id)
1850 {
1851 log_query_info(VERB_QUERY, "resolving (init part 3): ",
1852 &qstate->qinfo);
1853 /* if the cache reply dp equals a validation anchor or msg has DS,
1854 * then DNSSEC RRSIGs are expected in the reply */
1855 iq->dnssec_expected = iter_indicates_dnssec(qstate->env, iq->dp,
1856 iq->deleg_msg, iq->qchase.qclass);
1857
1858 /* If the RD flag wasn't set, then we just finish with the
1859 * cached referral as the response. */
1860 if(!(qstate->query_flags & BIT_RD) && iq->deleg_msg) {
1861 iq->response = iq->deleg_msg;
1862 if(verbosity >= VERB_ALGO && iq->response)
1863 log_dns_msg("no RD requested, using delegation msg",
1864 &iq->response->qinfo, iq->response->rep);
1865 if(qstate->reply_origin)
1866 sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region);
1867 return final_state(iq);
1868 }
1869 /* After this point, unset the RD flag -- this query is going to
1870 * be sent to an auth. server. */
1871 iq->chase_flags &= ~BIT_RD;
1872
1873 /* if dnssec expected, fetch key for the trust-anchor or cached-DS */
1874 if(iq->dnssec_expected && qstate->env->cfg->prefetch_key &&
1875 !(qstate->query_flags&BIT_CD)) {
1876 generate_dnskey_prefetch(qstate, iq, id);
1877 fptr_ok(fptr_whitelist_modenv_detach_subs(
1878 qstate->env->detach_subs));
1879 (*qstate->env->detach_subs)(qstate);
1880 }
1881
1882 /* Jump to the next state. */
1883 return next_state(iq, QUERYTARGETS_STATE);
1884 }
1885
1886 /**
1887 * Given a basic query, generate a parent-side "target" query.
1888 * These are subordinate queries for missing delegation point target addresses,
1889 * for which only the parent of the delegation provides correct IP addresses.
1890 *
1891 * @param qstate: query state.
1892 * @param iq: iterator query state.
1893 * @param id: module id.
1894 * @param name: target qname.
1895 * @param namelen: target qname length.
1896 * @param qtype: target qtype (either A or AAAA).
1897 * @param qclass: target qclass.
1898 * @return true on success, false on failure.
1899 */
1900 static int
generate_parentside_target_query(struct module_qstate * qstate,struct iter_qstate * iq,int id,uint8_t * name,size_t namelen,uint16_t qtype,uint16_t qclass)1901 generate_parentside_target_query(struct module_qstate* qstate,
1902 struct iter_qstate* iq, int id, uint8_t* name, size_t namelen,
1903 uint16_t qtype, uint16_t qclass)
1904 {
1905 struct module_qstate* subq;
1906 if(!generate_sub_request(name, namelen, qtype, qclass, qstate,
1907 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0))
1908 return 0;
1909 if(subq) {
1910 struct iter_qstate* subiq =
1911 (struct iter_qstate*)subq->minfo[id];
1912 /* blacklist the cache - we want to fetch parent stuff */
1913 sock_list_insert(&subq->blacklist, NULL, 0, subq->region);
1914 subiq->query_for_pside_glue = 1;
1915 if(dname_subdomain_c(name, iq->dp->name)) {
1916 subiq->dp = delegpt_copy(iq->dp, subq->region);
1917 subiq->dnssec_expected = iter_indicates_dnssec(
1918 qstate->env, subiq->dp, NULL,
1919 subq->qinfo.qclass);
1920 subiq->refetch_glue = 1;
1921 } else {
1922 subiq->dp = dns_cache_find_delegation(qstate->env,
1923 name, namelen, qtype, qclass, subq->region,
1924 &subiq->deleg_msg,
1925 *qstate->env->now+subq->prefetch_leeway,
1926 1, NULL, 0);
1927 /* if no dp, then it's from root, refetch unneeded */
1928 if(subiq->dp) {
1929 subiq->dnssec_expected = iter_indicates_dnssec(
1930 qstate->env, subiq->dp, NULL,
1931 subq->qinfo.qclass);
1932 subiq->refetch_glue = 1;
1933 }
1934 }
1935 }
1936 log_nametypeclass(VERB_QUERY, "new pside target", name, qtype, qclass);
1937 return 1;
1938 }
1939
1940 /**
1941 * Given a basic query, generate a "target" query. These are subordinate
1942 * queries for missing delegation point target addresses.
1943 *
1944 * @param qstate: query state.
1945 * @param iq: iterator query state.
1946 * @param id: module id.
1947 * @param name: target qname.
1948 * @param namelen: target qname length.
1949 * @param qtype: target qtype (either A or AAAA).
1950 * @param qclass: target qclass.
1951 * @return true on success, false on failure.
1952 */
1953 static int
generate_target_query(struct module_qstate * qstate,struct iter_qstate * iq,int id,uint8_t * name,size_t namelen,uint16_t qtype,uint16_t qclass)1954 generate_target_query(struct module_qstate* qstate, struct iter_qstate* iq,
1955 int id, uint8_t* name, size_t namelen, uint16_t qtype, uint16_t qclass)
1956 {
1957 struct module_qstate* subq;
1958 if(!generate_sub_request(name, namelen, qtype, qclass, qstate,
1959 id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0))
1960 return 0;
1961 log_nametypeclass(VERB_QUERY, "new target", name, qtype, qclass);
1962 return 1;
1963 }
1964
1965 /**
1966 * Given an event at a certain state, generate zero or more target queries
1967 * for it's current delegation point.
1968 *
1969 * @param qstate: query state.
1970 * @param iq: iterator query state.
1971 * @param ie: iterator shared global environment.
1972 * @param id: module id.
1973 * @param maxtargets: The maximum number of targets to query for.
1974 * if it is negative, there is no maximum number of targets.
1975 * @param num: returns the number of queries generated and processed,
1976 * which may be zero if there were no missing targets.
1977 * @return false on error.
1978 */
1979 static int
query_for_targets(struct module_qstate * qstate,struct iter_qstate * iq,struct iter_env * ie,int id,int maxtargets,int * num)1980 query_for_targets(struct module_qstate* qstate, struct iter_qstate* iq,
1981 struct iter_env* ie, int id, int maxtargets, int* num)
1982 {
1983 int query_count = 0;
1984 struct delegpt_ns* ns;
1985 int missing;
1986 int toget = 0;
1987
1988 iter_mark_cycle_targets(qstate, iq->dp);
1989 missing = (int)delegpt_count_missing_targets(iq->dp, NULL);
1990 log_assert(maxtargets != 0); /* that would not be useful */
1991
1992 /* Generate target requests. Basically, any missing targets
1993 * are queried for here, regardless if it is necessary to do
1994 * so to continue processing. */
1995 if(maxtargets < 0 || maxtargets > missing)
1996 toget = missing;
1997 else toget = maxtargets;
1998 if(toget == 0) {
1999 *num = 0;
2000 return 1;
2001 }
2002
2003 /* now that we are sure that a target query is going to be made,
2004 * check the limits. */
2005 if(iq->depth == ie->max_dependency_depth)
2006 return 0;
2007 if(iq->depth > 0 && iq->target_count &&
2008 iq->target_count[TARGET_COUNT_QUERIES] > MAX_TARGET_COUNT) {
2009 char s[LDNS_MAX_DOMAINLEN+1];
2010 dname_str(qstate->qinfo.qname, s);
2011 verbose(VERB_QUERY, "request %s has exceeded the maximum "
2012 "number of glue fetches %d", s,
2013 iq->target_count[TARGET_COUNT_QUERIES]);
2014 return 0;
2015 }
2016 if(iq->dp_target_count > MAX_DP_TARGET_COUNT) {
2017 char s[LDNS_MAX_DOMAINLEN+1];
2018 dname_str(qstate->qinfo.qname, s);
2019 verbose(VERB_QUERY, "request %s has exceeded the maximum "
2020 "number of glue fetches %d to a single delegation point",
2021 s, iq->dp_target_count);
2022 return 0;
2023 }
2024
2025 /* select 'toget' items from the total of 'missing' items */
2026 log_assert(toget <= missing);
2027
2028 /* loop over missing targets */
2029 for(ns = iq->dp->nslist; ns; ns = ns->next) {
2030 if(ns->resolved)
2031 continue;
2032
2033 /* randomly select this item with probability toget/missing */
2034 if(!iter_ns_probability(qstate->env->rnd, toget, missing)) {
2035 /* do not select this one, next; select toget number
2036 * of items from a list one less in size */
2037 missing --;
2038 continue;
2039 }
2040
2041 if(ie->supports_ipv6 &&
2042 ((ns->lame && !ns->done_pside6) ||
2043 (!ns->lame && !ns->got6))) {
2044 /* Send the AAAA request. */
2045 if(!generate_target_query(qstate, iq, id,
2046 ns->name, ns->namelen,
2047 LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) {
2048 *num = query_count;
2049 if(query_count > 0)
2050 qstate->ext_state[id] = module_wait_subquery;
2051 return 0;
2052 }
2053 query_count++;
2054 /* If the mesh query list is full, exit the loop here.
2055 * This makes the routine spawn one query at a time,
2056 * and this means there is no query state load
2057 * increase, because the spawned state uses cpu and a
2058 * socket while this state waits for that spawned
2059 * state. Next time we can look up further targets */
2060 if(mesh_jostle_exceeded(qstate->env->mesh))
2061 break;
2062 }
2063 /* Send the A request. */
2064 if((ie->supports_ipv4 || ie->use_nat64) &&
2065 ((ns->lame && !ns->done_pside4) ||
2066 (!ns->lame && !ns->got4))) {
2067 if(!generate_target_query(qstate, iq, id,
2068 ns->name, ns->namelen,
2069 LDNS_RR_TYPE_A, iq->qchase.qclass)) {
2070 *num = query_count;
2071 if(query_count > 0)
2072 qstate->ext_state[id] = module_wait_subquery;
2073 return 0;
2074 }
2075 query_count++;
2076 /* If the mesh query list is full, exit the loop. */
2077 if(mesh_jostle_exceeded(qstate->env->mesh))
2078 break;
2079 }
2080
2081 /* mark this target as in progress. */
2082 ns->resolved = 1;
2083 missing--;
2084 toget--;
2085 if(toget == 0)
2086 break;
2087 }
2088 *num = query_count;
2089 if(query_count > 0)
2090 qstate->ext_state[id] = module_wait_subquery;
2091
2092 return 1;
2093 }
2094
2095 /**
2096 * Called by processQueryTargets when it would like extra targets to query
2097 * but it seems to be out of options. At last resort some less appealing
2098 * options are explored. If there are no more options, the result is SERVFAIL
2099 *
2100 * @param qstate: query state.
2101 * @param iq: iterator query state.
2102 * @param ie: iterator shared global environment.
2103 * @param id: module id.
2104 * @return true if the event requires more request processing immediately,
2105 * false if not.
2106 */
2107 static int
processLastResort(struct module_qstate * qstate,struct iter_qstate * iq,struct iter_env * ie,int id)2108 processLastResort(struct module_qstate* qstate, struct iter_qstate* iq,
2109 struct iter_env* ie, int id)
2110 {
2111 struct delegpt_ns* ns;
2112 int query_count = 0;
2113 verbose(VERB_ALGO, "No more query targets, attempting last resort");
2114 log_assert(iq->dp);
2115
2116 if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen,
2117 iq->qchase.qclass, NULL, NULL, NULL)) {
2118 /* fail -- no more targets, no more hope of targets, no hope
2119 * of a response. */
2120 errinf(qstate, "all the configured stub or forward servers failed,");
2121 errinf_dname(qstate, "at zone", iq->dp->name);
2122 errinf_reply(qstate, iq);
2123 verbose(VERB_QUERY, "configured stub or forward servers failed -- returning SERVFAIL");
2124 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
2125 }
2126 if(!iq->dp->has_parent_side_NS && dname_is_root(iq->dp->name)) {
2127 struct delegpt* dp;
2128 int nolock = 0;
2129 dp = hints_find_root(qstate->env->hints,
2130 iq->qchase.qclass, nolock);
2131 if(dp) {
2132 struct delegpt_addr* a;
2133 iq->chase_flags &= ~BIT_RD; /* go to authorities */
2134 for(ns = dp->nslist; ns; ns=ns->next) {
2135 (void)delegpt_add_ns(iq->dp, qstate->region,
2136 ns->name, ns->lame, ns->tls_auth_name,
2137 ns->port);
2138 }
2139 for(a = dp->target_list; a; a=a->next_target) {
2140 (void)delegpt_add_addr(iq->dp, qstate->region,
2141 &a->addr, a->addrlen, a->bogus,
2142 a->lame, a->tls_auth_name, -1, NULL);
2143 }
2144 lock_rw_unlock(&qstate->env->hints->lock);
2145 }
2146 iq->dp->has_parent_side_NS = 1;
2147 } else if(!iq->dp->has_parent_side_NS) {
2148 if(!iter_lookup_parent_NS_from_cache(qstate->env, iq->dp,
2149 qstate->region, &qstate->qinfo)
2150 || !iq->dp->has_parent_side_NS) {
2151 /* if: malloc failure in lookup go up to try */
2152 /* if: no parent NS in cache - go up one level */
2153 verbose(VERB_ALGO, "try to grab parent NS");
2154 iq->store_parent_NS = iq->dp;
2155 iq->chase_flags &= ~BIT_RD; /* go to authorities */
2156 iq->deleg_msg = NULL;
2157 iq->refetch_glue = 1;
2158 iq->query_restart_count++;
2159 iq->sent_count = 0;
2160 iq->dp_target_count = 0;
2161 if(qstate->env->cfg->qname_minimisation)
2162 iq->minimisation_state = INIT_MINIMISE_STATE;
2163 return next_state(iq, INIT_REQUEST_STATE);
2164 }
2165 }
2166 /* see if that makes new names available */
2167 if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
2168 qstate->region, iq->dp))
2169 log_err("out of memory in cache_fill_missing");
2170 if(iq->dp->usable_list) {
2171 verbose(VERB_ALGO, "try parent-side-name, w. glue from cache");
2172 return next_state(iq, QUERYTARGETS_STATE);
2173 }
2174 /* try to fill out parent glue from cache */
2175 if(iter_lookup_parent_glue_from_cache(qstate->env, iq->dp,
2176 qstate->region, &qstate->qinfo)) {
2177 /* got parent stuff from cache, see if we can continue */
2178 verbose(VERB_ALGO, "try parent-side glue from cache");
2179 return next_state(iq, QUERYTARGETS_STATE);
2180 }
2181 /* query for an extra name added by the parent-NS record */
2182 if(delegpt_count_missing_targets(iq->dp, NULL) > 0) {
2183 int qs = 0;
2184 verbose(VERB_ALGO, "try parent-side target name");
2185 if(!query_for_targets(qstate, iq, ie, id, 1, &qs)) {
2186 errinf(qstate, "could not fetch nameserver");
2187 errinf_dname(qstate, "at zone", iq->dp->name);
2188 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2189 }
2190 iq->num_target_queries += qs;
2191 target_count_increase(iq, qs);
2192 if(qs != 0) {
2193 qstate->ext_state[id] = module_wait_subquery;
2194 return 0; /* and wait for them */
2195 }
2196 }
2197 if(iq->depth == ie->max_dependency_depth) {
2198 verbose(VERB_QUERY, "maxdepth and need more nameservers, fail");
2199 errinf(qstate, "cannot fetch more nameservers because at max dependency depth");
2200 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
2201 }
2202 if(iq->depth > 0 && iq->target_count &&
2203 iq->target_count[TARGET_COUNT_QUERIES] > MAX_TARGET_COUNT) {
2204 char s[LDNS_MAX_DOMAINLEN+1];
2205 dname_str(qstate->qinfo.qname, s);
2206 verbose(VERB_QUERY, "request %s has exceeded the maximum "
2207 "number of glue fetches %d", s,
2208 iq->target_count[TARGET_COUNT_QUERIES]);
2209 errinf(qstate, "exceeded the maximum number of glue fetches");
2210 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
2211 }
2212 /* mark cycle targets for parent-side lookups */
2213 iter_mark_pside_cycle_targets(qstate, iq->dp);
2214 /* see if we can issue queries to get nameserver addresses */
2215 /* this lookup is not randomized, but sequential. */
2216 for(ns = iq->dp->nslist; ns; ns = ns->next) {
2217 /* if this nameserver is at a delegation point, but that
2218 * delegation point is a stub and we cannot go higher, skip*/
2219 if( ((ie->supports_ipv6 && !ns->done_pside6) ||
2220 ((ie->supports_ipv4 || ie->use_nat64) && !ns->done_pside4)) &&
2221 !can_have_last_resort(qstate->env, ns->name, ns->namelen,
2222 iq->qchase.qclass, NULL, NULL, NULL)) {
2223 log_nametypeclass(VERB_ALGO, "cannot pside lookup ns "
2224 "because it is also a stub/forward,",
2225 ns->name, LDNS_RR_TYPE_NS, iq->qchase.qclass);
2226 if(ie->supports_ipv6) ns->done_pside6 = 1;
2227 if(ie->supports_ipv4 || ie->use_nat64) ns->done_pside4 = 1;
2228 continue;
2229 }
2230 /* query for parent-side A and AAAA for nameservers */
2231 if(ie->supports_ipv6 && !ns->done_pside6) {
2232 /* Send the AAAA request. */
2233 if(!generate_parentside_target_query(qstate, iq, id,
2234 ns->name, ns->namelen,
2235 LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) {
2236 errinf_dname(qstate, "could not generate nameserver AAAA lookup for", ns->name);
2237 return error_response(qstate, id,
2238 LDNS_RCODE_SERVFAIL);
2239 }
2240 ns->done_pside6 = 1;
2241 query_count++;
2242 if(mesh_jostle_exceeded(qstate->env->mesh)) {
2243 /* Wait for the lookup; do not spawn multiple
2244 * lookups at a time. */
2245 verbose(VERB_ALGO, "try parent-side glue lookup");
2246 iq->num_target_queries += query_count;
2247 target_count_increase(iq, query_count);
2248 qstate->ext_state[id] = module_wait_subquery;
2249 return 0;
2250 }
2251 }
2252 if((ie->supports_ipv4 || ie->use_nat64) && !ns->done_pside4) {
2253 /* Send the A request. */
2254 if(!generate_parentside_target_query(qstate, iq, id,
2255 ns->name, ns->namelen,
2256 LDNS_RR_TYPE_A, iq->qchase.qclass)) {
2257 errinf_dname(qstate, "could not generate nameserver A lookup for", ns->name);
2258 return error_response(qstate, id,
2259 LDNS_RCODE_SERVFAIL);
2260 }
2261 ns->done_pside4 = 1;
2262 query_count++;
2263 }
2264 if(query_count != 0) { /* suspend to await results */
2265 verbose(VERB_ALGO, "try parent-side glue lookup");
2266 iq->num_target_queries += query_count;
2267 target_count_increase(iq, query_count);
2268 qstate->ext_state[id] = module_wait_subquery;
2269 return 0;
2270 }
2271 }
2272
2273 /* if this was a parent-side glue query itself, then store that
2274 * failure in cache. */
2275 if(!qstate->no_cache_store && iq->query_for_pside_glue
2276 && !iq->pside_glue)
2277 iter_store_parentside_neg(qstate->env, &qstate->qinfo,
2278 iq->deleg_msg?iq->deleg_msg->rep:
2279 (iq->response?iq->response->rep:NULL));
2280
2281 errinf(qstate, "all servers for this domain failed,");
2282 errinf_dname(qstate, "at zone", iq->dp->name);
2283 errinf_reply(qstate, iq);
2284 verbose(VERB_QUERY, "out of query targets -- returning SERVFAIL");
2285 /* fail -- no more targets, no more hope of targets, no hope
2286 * of a response. */
2287 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
2288 }
2289
2290 /**
2291 * Try to find the NS record set that will resolve a qtype DS query. Due
2292 * to grandparent/grandchild reasons we did not get a proper lookup right
2293 * away. We need to create type NS queries until we get the right parent
2294 * for this lookup. We remove labels from the query to find the right point.
2295 * If we end up at the old dp name, then there is no solution.
2296 *
2297 * @param qstate: query state.
2298 * @param iq: iterator query state.
2299 * @param id: module id.
2300 * @return true if the event requires more immediate processing, false if
2301 * not. This is generally only true when forwarding the request to
2302 * the final state (i.e., on answer).
2303 */
2304 static int
processDSNSFind(struct module_qstate * qstate,struct iter_qstate * iq,int id)2305 processDSNSFind(struct module_qstate* qstate, struct iter_qstate* iq, int id)
2306 {
2307 struct module_qstate* subq = NULL;
2308 verbose(VERB_ALGO, "processDSNSFind");
2309
2310 if(!iq->dsns_point) {
2311 /* initialize */
2312 iq->dsns_point = iq->qchase.qname;
2313 iq->dsns_point_len = iq->qchase.qname_len;
2314 }
2315 /* robustcheck for internal error: we are not underneath the dp */
2316 if(!dname_subdomain_c(iq->dsns_point, iq->dp->name)) {
2317 errinf_dname(qstate, "for DS query parent-child nameserver search the query is not under the zone", iq->dp->name);
2318 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
2319 }
2320
2321 /* go up one (more) step, until we hit the dp, if so, end */
2322 dname_remove_label(&iq->dsns_point, &iq->dsns_point_len);
2323 if(query_dname_compare(iq->dsns_point, iq->dp->name) == 0) {
2324 /* there was no inbetween nameserver, use the old delegation
2325 * point again. And this time, because dsns_point is nonNULL
2326 * we are going to accept the (bad) result */
2327 iq->state = QUERYTARGETS_STATE;
2328 return 1;
2329 }
2330 iq->state = DSNS_FIND_STATE;
2331
2332 /* spawn NS lookup (validation not needed, this is for DS lookup) */
2333 log_nametypeclass(VERB_ALGO, "fetch nameservers",
2334 iq->dsns_point, LDNS_RR_TYPE_NS, iq->qchase.qclass);
2335 if(!generate_sub_request(iq->dsns_point, iq->dsns_point_len,
2336 LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
2337 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0, 0)) {
2338 errinf_dname(qstate, "for DS query parent-child nameserver search, could not generate NS lookup for", iq->dsns_point);
2339 return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
2340 }
2341
2342 return 0;
2343 }
2344
2345 /**
2346 * Check if we wait responses for sent queries and update the iterator's
2347 * external state.
2348 */
2349 static void
check_waiting_queries(struct iter_qstate * iq,struct module_qstate * qstate,int id)2350 check_waiting_queries(struct iter_qstate* iq, struct module_qstate* qstate,
2351 int id)
2352 {
2353 if(iq->num_target_queries>0 && iq->num_current_queries>0) {
2354 verbose(VERB_ALGO, "waiting for %d targets to "
2355 "resolve or %d outstanding queries to "
2356 "respond", iq->num_target_queries,
2357 iq->num_current_queries);
2358 qstate->ext_state[id] = module_wait_reply;
2359 } else if(iq->num_target_queries>0) {
2360 verbose(VERB_ALGO, "waiting for %d targets to "
2361 "resolve", iq->num_target_queries);
2362 qstate->ext_state[id] = module_wait_subquery;
2363 } else {
2364 verbose(VERB_ALGO, "waiting for %d "
2365 "outstanding queries to respond",
2366 iq->num_current_queries);
2367 qstate->ext_state[id] = module_wait_reply;
2368 }
2369 }
2370
2371 /**
2372 * This is the request event state where the request will be sent to one of
2373 * its current query targets. This state also handles issuing target lookup
2374 * queries for missing target IP addresses. Queries typically iterate on
2375 * this state, both when they are just trying different targets for a given
2376 * delegation point, and when they change delegation points. This state
2377 * roughly corresponds to RFC 1034 algorithm steps 3 and 4.
2378 *
2379 * @param qstate: query state.
2380 * @param iq: iterator query state.
2381 * @param ie: iterator shared global environment.
2382 * @param id: module id.
2383 * @return true if the event requires more request processing immediately,
2384 * false if not. This state only returns true when it is generating
2385 * a SERVFAIL response because the query has hit a dead end.
2386 */
2387 static int
processQueryTargets(struct module_qstate * qstate,struct iter_qstate * iq,struct iter_env * ie,int id)2388 processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
2389 struct iter_env* ie, int id)
2390 {
2391 int tf_policy;
2392 struct delegpt_addr* target;
2393 struct outbound_entry* outq;
2394 struct sockaddr_storage real_addr;
2395 socklen_t real_addrlen;
2396 int auth_fallback = 0;
2397 uint8_t* qout_orig = NULL;
2398 size_t qout_orig_len = 0;
2399 int sq_check_ratelimit = 1;
2400 int sq_was_ratelimited = 0;
2401 int can_do_promisc = 0;
2402
2403 /* NOTE: a request will encounter this state for each target it
2404 * needs to send a query to. That is, at least one per referral,
2405 * more if some targets timeout or return throwaway answers. */
2406
2407 log_query_info(VERB_QUERY, "processQueryTargets:", &qstate->qinfo);
2408 verbose(VERB_ALGO, "processQueryTargets: targetqueries %d, "
2409 "currentqueries %d sentcount %d", iq->num_target_queries,
2410 iq->num_current_queries, iq->sent_count);
2411
2412 /* Make sure that we haven't run away */
2413 if(iq->referral_count > MAX_REFERRAL_COUNT) {
2414 verbose(VERB_QUERY, "request has exceeded the maximum "
2415 "number of referrrals with %d", iq->referral_count);
2416 errinf(qstate, "exceeded the maximum of referrals");
2417 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2418 }
2419 if(iq->sent_count > ie->max_sent_count) {
2420 verbose(VERB_QUERY, "request has exceeded the maximum "
2421 "number of sends with %d", iq->sent_count);
2422 errinf(qstate, "exceeded the maximum number of sends");
2423 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2424 }
2425
2426 /* Check if we reached MAX_TARGET_NX limit without a fallback activation. */
2427 if(iq->target_count && !*iq->nxns_dp &&
2428 iq->target_count[TARGET_COUNT_NX] > MAX_TARGET_NX) {
2429 struct delegpt_ns* ns;
2430 /* If we can wait for resolution, do so. */
2431 if(iq->num_target_queries>0 || iq->num_current_queries>0) {
2432 check_waiting_queries(iq, qstate, id);
2433 return 0;
2434 }
2435 verbose(VERB_ALGO, "request has exceeded the maximum "
2436 "number of nxdomain nameserver lookups (%d) with %d",
2437 MAX_TARGET_NX, iq->target_count[TARGET_COUNT_NX]);
2438 /* Check for dp because we require one below */
2439 if(!iq->dp) {
2440 verbose(VERB_QUERY, "Failed to get a delegation, "
2441 "giving up");
2442 errinf(qstate, "failed to get a delegation (eg. prime "
2443 "failure)");
2444 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2445 }
2446 /* We reached the limit but we already have parent side
2447 * information; stop resolution */
2448 if(iq->dp->has_parent_side_NS) {
2449 verbose(VERB_ALGO, "parent-side information is "
2450 "already present for the delegation point, no "
2451 "fallback possible");
2452 errinf(qstate, "exceeded the maximum nameserver nxdomains");
2453 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2454 }
2455 verbose(VERB_ALGO, "initiating parent-side fallback for "
2456 "nxdomain nameserver lookups");
2457 /* Mark all the current NSes as resolved to allow for parent
2458 * fallback */
2459 for(ns=iq->dp->nslist; ns; ns=ns->next) {
2460 ns->resolved = 1;
2461 }
2462 /* Note the delegation point that triggered the NXNS fallback;
2463 * no reason for shared queries to keep trying there.
2464 * This also marks the fallback activation. */
2465 *iq->nxns_dp = malloc(iq->dp->namelen);
2466 if(!*iq->nxns_dp) {
2467 verbose(VERB_ALGO, "out of memory while initiating "
2468 "fallback");
2469 errinf(qstate, "exceeded the maximum nameserver "
2470 "nxdomains (malloc)");
2471 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2472 }
2473 memcpy(*iq->nxns_dp, iq->dp->name, iq->dp->namelen);
2474 } else if(iq->target_count && *iq->nxns_dp) {
2475 /* Handle the NXNS fallback case. */
2476 /* If we can wait for resolution, do so. */
2477 if(iq->num_target_queries>0 || iq->num_current_queries>0) {
2478 check_waiting_queries(iq, qstate, id);
2479 return 0;
2480 }
2481 /* Check for dp because we require one below */
2482 if(!iq->dp) {
2483 verbose(VERB_QUERY, "Failed to get a delegation, "
2484 "giving up");
2485 errinf(qstate, "failed to get a delegation (eg. prime "
2486 "failure)");
2487 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2488 }
2489
2490 if(iq->target_count[TARGET_COUNT_NX] > MAX_TARGET_NX_FALLBACK) {
2491 verbose(VERB_ALGO, "request has exceeded the maximum "
2492 "number of fallback nxdomain nameserver "
2493 "lookups (%d) with %d", MAX_TARGET_NX_FALLBACK,
2494 iq->target_count[TARGET_COUNT_NX]);
2495 errinf(qstate, "exceeded the maximum nameserver nxdomains");
2496 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2497 }
2498
2499 if(!iq->dp->has_parent_side_NS) {
2500 struct delegpt_ns* ns;
2501 if(!dname_canonical_compare(*iq->nxns_dp, iq->dp->name)) {
2502 verbose(VERB_ALGO, "this delegation point "
2503 "initiated the fallback, marking the "
2504 "nslist as resolved");
2505 for(ns=iq->dp->nslist; ns; ns=ns->next) {
2506 ns->resolved = 1;
2507 }
2508 }
2509 }
2510 }
2511
2512 /* Make sure we have a delegation point, otherwise priming failed
2513 * or another failure occurred */
2514 if(!iq->dp) {
2515 verbose(VERB_QUERY, "Failed to get a delegation, giving up");
2516 errinf(qstate, "failed to get a delegation (eg. prime failure)");
2517 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2518 }
2519 if(!ie->supports_ipv6)
2520 delegpt_no_ipv6(iq->dp);
2521 if(!ie->supports_ipv4 && !ie->use_nat64)
2522 delegpt_no_ipv4(iq->dp);
2523 delegpt_log(VERB_ALGO, iq->dp);
2524
2525 if(iq->num_current_queries>0) {
2526 /* already busy answering a query, this restart is because
2527 * more delegpt addrs became available, wait for existing
2528 * query. */
2529 verbose(VERB_ALGO, "woke up, but wait for outstanding query");
2530 qstate->ext_state[id] = module_wait_reply;
2531 return 0;
2532 }
2533
2534 if(iq->minimisation_state == INIT_MINIMISE_STATE
2535 && !(iq->chase_flags & BIT_RD)) {
2536 /* (Re)set qinfo_out to (new) delegation point, except when
2537 * qinfo_out is already a subdomain of dp. This happens when
2538 * increasing by more than one label at once (QNAMEs with more
2539 * than MAX_MINIMISE_COUNT labels). */
2540 if(!(iq->qinfo_out.qname_len
2541 && dname_subdomain_c(iq->qchase.qname,
2542 iq->qinfo_out.qname)
2543 && dname_subdomain_c(iq->qinfo_out.qname,
2544 iq->dp->name))) {
2545 iq->qinfo_out.qname = iq->dp->name;
2546 iq->qinfo_out.qname_len = iq->dp->namelen;
2547 iq->qinfo_out.qtype = LDNS_RR_TYPE_A;
2548 iq->qinfo_out.qclass = iq->qchase.qclass;
2549 iq->qinfo_out.local_alias = NULL;
2550 iq->minimise_count = 0;
2551 }
2552
2553 iq->minimisation_state = MINIMISE_STATE;
2554 }
2555 if(iq->minimisation_state == MINIMISE_STATE) {
2556 int qchaselabs = dname_count_labels(iq->qchase.qname);
2557 int labdiff = qchaselabs -
2558 dname_count_labels(iq->qinfo_out.qname);
2559
2560 qout_orig = iq->qinfo_out.qname;
2561 qout_orig_len = iq->qinfo_out.qname_len;
2562 iq->qinfo_out.qname = iq->qchase.qname;
2563 iq->qinfo_out.qname_len = iq->qchase.qname_len;
2564 iq->minimise_count++;
2565 iq->timeout_count = 0;
2566
2567 iter_dec_attempts(iq->dp, 1, ie->outbound_msg_retry);
2568
2569 /* Limit number of iterations for QNAMEs with more
2570 * than MAX_MINIMISE_COUNT labels. Send first MINIMISE_ONE_LAB
2571 * labels of QNAME always individually.
2572 */
2573 if(qchaselabs > MAX_MINIMISE_COUNT && labdiff > 1 &&
2574 iq->minimise_count > MINIMISE_ONE_LAB) {
2575 if(iq->minimise_count < MAX_MINIMISE_COUNT) {
2576 int multilabs = qchaselabs - 1 -
2577 MINIMISE_ONE_LAB;
2578 int extralabs = multilabs /
2579 MINIMISE_MULTIPLE_LABS;
2580
2581 if (MAX_MINIMISE_COUNT - iq->minimise_count >=
2582 multilabs % MINIMISE_MULTIPLE_LABS)
2583 /* Default behaviour is to add 1 label
2584 * every iteration. Therefore, decrement
2585 * the extralabs by 1 */
2586 extralabs--;
2587 if (extralabs < labdiff)
2588 labdiff -= extralabs;
2589 else
2590 labdiff = 1;
2591 }
2592 /* Last minimised iteration, send all labels with
2593 * QTYPE=NS */
2594 else
2595 labdiff = 1;
2596 }
2597
2598 if(labdiff > 1) {
2599 verbose(VERB_QUERY, "removing %d labels", labdiff-1);
2600 dname_remove_labels(&iq->qinfo_out.qname,
2601 &iq->qinfo_out.qname_len,
2602 labdiff-1);
2603 }
2604 if(labdiff < 1 || (labdiff < 2
2605 && (iq->qchase.qtype == LDNS_RR_TYPE_DS
2606 || iq->qchase.qtype == LDNS_RR_TYPE_A)))
2607 /* Stop minimising this query, resolve "as usual" */
2608 iq->minimisation_state = DONOT_MINIMISE_STATE;
2609 else if(!qstate->no_cache_lookup) {
2610 struct dns_msg* msg = dns_cache_lookup(qstate->env,
2611 iq->qinfo_out.qname, iq->qinfo_out.qname_len,
2612 iq->qinfo_out.qtype, iq->qinfo_out.qclass,
2613 qstate->query_flags, qstate->region,
2614 qstate->env->scratch, 0, iq->dp->name,
2615 iq->dp->namelen);
2616 if(msg && FLAGS_GET_RCODE(msg->rep->flags) ==
2617 LDNS_RCODE_NOERROR)
2618 /* no need to send query if it is already
2619 * cached as NOERROR */
2620 return 1;
2621 if(msg && FLAGS_GET_RCODE(msg->rep->flags) ==
2622 LDNS_RCODE_NXDOMAIN &&
2623 qstate->env->need_to_validate &&
2624 qstate->env->cfg->harden_below_nxdomain) {
2625 if(msg->rep->security == sec_status_secure) {
2626 iq->response = msg;
2627 return final_state(iq);
2628 }
2629 if(msg->rep->security == sec_status_unchecked) {
2630 struct module_qstate* subq = NULL;
2631 if(!generate_sub_request(
2632 iq->qinfo_out.qname,
2633 iq->qinfo_out.qname_len,
2634 iq->qinfo_out.qtype,
2635 iq->qinfo_out.qclass,
2636 qstate, id, iq,
2637 INIT_REQUEST_STATE,
2638 FINISHED_STATE, &subq, 1, 1))
2639 verbose(VERB_ALGO,
2640 "could not validate NXDOMAIN "
2641 "response");
2642 }
2643 }
2644 if(msg && FLAGS_GET_RCODE(msg->rep->flags) ==
2645 LDNS_RCODE_NXDOMAIN) {
2646 /* return and add a label in the next
2647 * minimisation iteration.
2648 */
2649 return 1;
2650 }
2651 }
2652 }
2653 if(iq->minimisation_state == SKIP_MINIMISE_STATE) {
2654 if(iq->timeout_count < MAX_MINIMISE_TIMEOUT_COUNT)
2655 /* Do not increment qname, continue incrementing next
2656 * iteration */
2657 iq->minimisation_state = MINIMISE_STATE;
2658 else if(!qstate->env->cfg->qname_minimisation_strict)
2659 /* Too many time-outs detected for this QNAME and QTYPE.
2660 * We give up, disable QNAME minimisation. */
2661 iq->minimisation_state = DONOT_MINIMISE_STATE;
2662 }
2663 if(iq->minimisation_state == DONOT_MINIMISE_STATE)
2664 iq->qinfo_out = iq->qchase;
2665
2666 /* now find an answer to this query */
2667 /* see if authority zones have an answer */
2668 /* now we know the dp, we can check the auth zone for locally hosted
2669 * contents */
2670 if(!iq->auth_zone_avoid && qstate->blacklist) {
2671 if(auth_zones_can_fallback(qstate->env->auth_zones,
2672 iq->dp->name, iq->dp->namelen, iq->qinfo_out.qclass)) {
2673 /* if cache is blacklisted and this zone allows us
2674 * to fallback to the internet, then do so, and
2675 * fetch results from the internet servers */
2676 iq->auth_zone_avoid = 1;
2677 }
2678 }
2679 if(iq->auth_zone_avoid) {
2680 iq->auth_zone_avoid = 0;
2681 auth_fallback = 1;
2682 } else if(auth_zones_lookup(qstate->env->auth_zones, &iq->qinfo_out,
2683 qstate->region, &iq->response, &auth_fallback, iq->dp->name,
2684 iq->dp->namelen)) {
2685 /* use this as a response to be processed by the iterator */
2686 if(verbosity >= VERB_ALGO) {
2687 log_dns_msg("msg from auth zone",
2688 &iq->response->qinfo, iq->response->rep);
2689 }
2690 if((iq->chase_flags&BIT_RD) && !(iq->response->rep->flags&BIT_AA)) {
2691 verbose(VERB_ALGO, "forwarder, ignoring referral from auth zone");
2692 } else {
2693 lock_rw_wrlock(&qstate->env->auth_zones->lock);
2694 qstate->env->auth_zones->num_query_up++;
2695 lock_rw_unlock(&qstate->env->auth_zones->lock);
2696 iq->num_current_queries++;
2697 iq->chase_to_rd = 0;
2698 iq->dnssec_lame_query = 0;
2699 iq->auth_zone_response = 1;
2700 return next_state(iq, QUERY_RESP_STATE);
2701 }
2702 }
2703 iq->auth_zone_response = 0;
2704 if(auth_fallback == 0) {
2705 /* like we got servfail from the auth zone lookup, and
2706 * no internet fallback */
2707 verbose(VERB_ALGO, "auth zone lookup failed, no fallback,"
2708 " servfail");
2709 errinf(qstate, "auth zone lookup failed, fallback is off");
2710 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2711 }
2712 if(iq->dp->auth_dp) {
2713 /* we wanted to fallback, but had no delegpt, only the
2714 * auth zone generated delegpt, create an actual one */
2715 iq->auth_zone_avoid = 1;
2716 return next_state(iq, INIT_REQUEST_STATE);
2717 }
2718 /* but mostly, fallback==1 (like, when no such auth zone exists)
2719 * and we continue with lookups */
2720
2721 tf_policy = 0;
2722 /* < not <=, because although the array is large enough for <=, the
2723 * generated query will immediately be discarded due to depth and
2724 * that servfail is cached, which is not good as opportunism goes. */
2725 if(iq->depth < ie->max_dependency_depth
2726 && iq->num_target_queries == 0
2727 && (!iq->target_count || iq->target_count[TARGET_COUNT_NX]==0)
2728 && iq->sent_count < TARGET_FETCH_STOP) {
2729 can_do_promisc = 1;
2730 }
2731 /* if the mesh query list is full, then do not waste cpu and sockets to
2732 * fetch promiscuous targets. They can be looked up when needed. */
2733 if(can_do_promisc && !mesh_jostle_exceeded(qstate->env->mesh)) {
2734 tf_policy = ie->target_fetch_policy[iq->depth];
2735 }
2736
2737 /* if in 0x20 fallback get as many targets as possible */
2738 if(iq->caps_fallback) {
2739 int extra = 0;
2740 size_t naddr, nres, navail;
2741 if(!query_for_targets(qstate, iq, ie, id, -1, &extra)) {
2742 errinf(qstate, "could not fetch nameservers for 0x20 fallback");
2743 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2744 }
2745 iq->num_target_queries += extra;
2746 target_count_increase(iq, extra);
2747 if(iq->num_target_queries > 0) {
2748 /* wait to get all targets, we want to try em */
2749 verbose(VERB_ALGO, "wait for all targets for fallback");
2750 qstate->ext_state[id] = module_wait_reply;
2751 /* undo qname minimise step because we'll get back here
2752 * to do it again */
2753 if(qout_orig && iq->minimise_count > 0) {
2754 iq->minimise_count--;
2755 iq->qinfo_out.qname = qout_orig;
2756 iq->qinfo_out.qname_len = qout_orig_len;
2757 }
2758 return 0;
2759 }
2760 /* did we do enough fallback queries already? */
2761 delegpt_count_addr(iq->dp, &naddr, &nres, &navail);
2762 /* the current caps_server is the number of fallbacks sent.
2763 * the original query is one that matched too, so we have
2764 * caps_server+1 number of matching queries now */
2765 if(iq->caps_server+1 >= naddr*3 ||
2766 iq->caps_server*2+2 >= (size_t)ie->max_sent_count) {
2767 /* *2 on sentcount check because ipv6 may fail */
2768 /* we're done, process the response */
2769 verbose(VERB_ALGO, "0x20 fallback had %d responses "
2770 "match for %d wanted, done.",
2771 (int)iq->caps_server+1, (int)naddr*3);
2772 iq->response = iq->caps_response;
2773 iq->caps_fallback = 0;
2774 iter_dec_attempts(iq->dp, 3, ie->outbound_msg_retry); /* space for fallback */
2775 iq->num_current_queries++; /* RespState decrements it*/
2776 iq->referral_count++; /* make sure we don't loop */
2777 iq->sent_count = 0;
2778 iq->dp_target_count = 0;
2779 iq->state = QUERY_RESP_STATE;
2780 return 1;
2781 }
2782 verbose(VERB_ALGO, "0x20 fallback number %d",
2783 (int)iq->caps_server);
2784
2785 /* if there is a policy to fetch missing targets
2786 * opportunistically, do it. we rely on the fact that once a
2787 * query (or queries) for a missing name have been issued,
2788 * they will not show up again. */
2789 } else if(tf_policy != 0) {
2790 int extra = 0;
2791 verbose(VERB_ALGO, "attempt to get extra %d targets",
2792 tf_policy);
2793 (void)query_for_targets(qstate, iq, ie, id, tf_policy, &extra);
2794 /* errors ignored, these targets are not strictly necessary for
2795 * this result, we do not have to reply with SERVFAIL */
2796 iq->num_target_queries += extra;
2797 target_count_increase(iq, extra);
2798 }
2799
2800 /* Add the current set of unused targets to our queue. */
2801 delegpt_add_unused_targets(iq->dp);
2802
2803 if(qstate->env->auth_zones) {
2804 uint8_t* sname = NULL;
2805 size_t snamelen = 0;
2806 /* apply rpz triggers at query time; nameserver IP and dname */
2807 struct dns_msg* forged_response_after_cname;
2808 struct dns_msg* forged_response = rpz_callback_from_iterator_module(qstate, iq);
2809 int count = 0;
2810 while(forged_response && reply_find_rrset_section_an(
2811 forged_response->rep, iq->qchase.qname,
2812 iq->qchase.qname_len, LDNS_RR_TYPE_CNAME,
2813 iq->qchase.qclass) &&
2814 iq->qchase.qtype != LDNS_RR_TYPE_CNAME &&
2815 count++ < ie->max_query_restarts) {
2816 /* another cname to follow */
2817 if(!handle_cname_response(qstate, iq, forged_response,
2818 &sname, &snamelen)) {
2819 errinf(qstate, "malloc failure, CNAME info");
2820 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2821 }
2822 iq->qchase.qname = sname;
2823 iq->qchase.qname_len = snamelen;
2824 forged_response_after_cname =
2825 rpz_callback_from_iterator_cname(qstate, iq);
2826 if(forged_response_after_cname) {
2827 forged_response = forged_response_after_cname;
2828 } else {
2829 /* Follow the CNAME with a query restart */
2830 iq->deleg_msg = NULL;
2831 iq->dp = NULL;
2832 iq->dsns_point = NULL;
2833 iq->auth_zone_response = 0;
2834 iq->refetch_glue = 0;
2835 iq->query_restart_count++;
2836 iq->sent_count = 0;
2837 iq->dp_target_count = 0;
2838 if(qstate->env->cfg->qname_minimisation)
2839 iq->minimisation_state = INIT_MINIMISE_STATE;
2840 outbound_list_clear(&iq->outlist);
2841 iq->num_current_queries = 0;
2842 fptr_ok(fptr_whitelist_modenv_detach_subs(
2843 qstate->env->detach_subs));
2844 (*qstate->env->detach_subs)(qstate);
2845 iq->num_target_queries = 0;
2846 return next_state(iq, INIT_REQUEST_STATE);
2847 }
2848 }
2849 if(forged_response != NULL) {
2850 qstate->ext_state[id] = module_finished;
2851 qstate->return_rcode = LDNS_RCODE_NOERROR;
2852 qstate->return_msg = forged_response;
2853 iq->response = forged_response;
2854 next_state(iq, FINISHED_STATE);
2855 if(!iter_prepend(iq, qstate->return_msg, qstate->region)) {
2856 log_err("rpz: prepend rrsets: out of memory");
2857 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
2858 }
2859 return 0;
2860 }
2861 }
2862
2863 /* Select the next usable target, filtering out unsuitable targets. */
2864 target = iter_server_selection(ie, qstate->env, iq->dp,
2865 iq->dp->name, iq->dp->namelen, iq->qchase.qtype,
2866 &iq->dnssec_lame_query, &iq->chase_to_rd,
2867 iq->num_target_queries, qstate->blacklist,
2868 qstate->prefetch_leeway);
2869
2870 /* If no usable target was selected... */
2871 if(!target) {
2872 /* Here we distinguish between three states: generate a new
2873 * target query, just wait, or quit (with a SERVFAIL).
2874 * We have the following information: number of active
2875 * target queries, number of active current queries,
2876 * the presence of missing targets at this delegation
2877 * point, and the given query target policy. */
2878
2879 /* Check for the wait condition. If this is true, then
2880 * an action must be taken. */
2881 if(iq->num_target_queries==0 && iq->num_current_queries==0) {
2882 /* If there is nothing to wait for, then we need
2883 * to distinguish between generating (a) new target
2884 * query, or failing. */
2885 if(delegpt_count_missing_targets(iq->dp, NULL) > 0) {
2886 int qs = 0;
2887 verbose(VERB_ALGO, "querying for next "
2888 "missing target");
2889 if(!query_for_targets(qstate, iq, ie, id,
2890 1, &qs)) {
2891 errinf(qstate, "could not fetch nameserver");
2892 errinf_dname(qstate, "at zone", iq->dp->name);
2893 return error_response(qstate, id,
2894 LDNS_RCODE_SERVFAIL);
2895 }
2896 if(qs == 0 &&
2897 delegpt_count_missing_targets(iq->dp, NULL) == 0){
2898 /* it looked like there were missing
2899 * targets, but they did not turn up.
2900 * Try the bad choices again (if any),
2901 * when we get back here missing==0,
2902 * so this is not a loop. */
2903 return 1;
2904 }
2905 iq->num_target_queries += qs;
2906 target_count_increase(iq, qs);
2907 }
2908 /* Since a target query might have been made, we
2909 * need to check again. */
2910 if(iq->num_target_queries == 0) {
2911 /* if in capsforid fallback, instead of last
2912 * resort, we agree with the current reply
2913 * we have (if any) (our count of addrs bad)*/
2914 if(iq->caps_fallback && iq->caps_reply) {
2915 /* we're done, process the response */
2916 verbose(VERB_ALGO, "0x20 fallback had %d responses, "
2917 "but no more servers except "
2918 "last resort, done.",
2919 (int)iq->caps_server+1);
2920 iq->response = iq->caps_response;
2921 iq->caps_fallback = 0;
2922 iter_dec_attempts(iq->dp, 3, ie->outbound_msg_retry); /* space for fallback */
2923 iq->num_current_queries++; /* RespState decrements it*/
2924 iq->referral_count++; /* make sure we don't loop */
2925 iq->sent_count = 0;
2926 iq->dp_target_count = 0;
2927 iq->state = QUERY_RESP_STATE;
2928 return 1;
2929 }
2930 return processLastResort(qstate, iq, ie, id);
2931 }
2932 }
2933
2934 /* otherwise, we have no current targets, so submerge
2935 * until one of the target or direct queries return. */
2936 verbose(VERB_ALGO, "no current targets");
2937 check_waiting_queries(iq, qstate, id);
2938 /* undo qname minimise step because we'll get back here
2939 * to do it again */
2940 if(qout_orig && iq->minimise_count > 0) {
2941 iq->minimise_count--;
2942 iq->qinfo_out.qname = qout_orig;
2943 iq->qinfo_out.qname_len = qout_orig_len;
2944 }
2945 return 0;
2946 }
2947
2948 /* We have a target. We could have created promiscuous target
2949 * queries but we are currently under pressure (mesh_jostle_exceeded).
2950 * If we are configured to allow promiscuous target queries and haven't
2951 * gone out to the network for a target query for this delegation, then
2952 * it is possible to slip in a promiscuous one with a 1/10 chance. */
2953 if(can_do_promisc && tf_policy == 0 && iq->depth == 0
2954 && iq->depth < ie->max_dependency_depth
2955 && ie->target_fetch_policy[iq->depth] != 0
2956 && iq->dp_target_count == 0
2957 && !ub_random_max(qstate->env->rnd, 10)) {
2958 int extra = 0;
2959 verbose(VERB_ALGO, "available target exists in cache but "
2960 "attempt to get extra 1 target");
2961 (void)query_for_targets(qstate, iq, ie, id, 1, &extra);
2962 /* errors ignored, these targets are not strictly necessary for
2963 * this result, we do not have to reply with SERVFAIL */
2964 if(extra > 0) {
2965 iq->num_target_queries += extra;
2966 target_count_increase(iq, extra);
2967 check_waiting_queries(iq, qstate, id);
2968 /* undo qname minimise step because we'll get back here
2969 * to do it again */
2970 if(qout_orig && iq->minimise_count > 0) {
2971 iq->minimise_count--;
2972 iq->qinfo_out.qname = qout_orig;
2973 iq->qinfo_out.qname_len = qout_orig_len;
2974 }
2975 return 0;
2976 }
2977 }
2978
2979 /* Do not check ratelimit for forwarding queries or if we already got a
2980 * pass. */
2981 sq_check_ratelimit = (!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok);
2982 /* We have a valid target. */
2983 if(verbosity >= VERB_QUERY) {
2984 log_query_info(VERB_QUERY, "sending query:", &iq->qinfo_out);
2985 log_name_addr(VERB_QUERY, "sending to target:", iq->dp->name,
2986 &target->addr, target->addrlen);
2987 verbose(VERB_ALGO, "dnssec status: %s%s",
2988 iq->dnssec_expected?"expected": "not expected",
2989 iq->dnssec_lame_query?" but lame_query anyway": "");
2990 }
2991
2992 real_addr = target->addr;
2993 real_addrlen = target->addrlen;
2994
2995 if(ie->use_nat64 && target->addr.ss_family == AF_INET) {
2996 addr_to_nat64(&target->addr, &ie->nat64_prefix_addr,
2997 ie->nat64_prefix_addrlen, ie->nat64_prefix_net,
2998 &real_addr, &real_addrlen);
2999 log_name_addr(VERB_QUERY, "applied NAT64:",
3000 iq->dp->name, &real_addr, real_addrlen);
3001 }
3002
3003 fptr_ok(fptr_whitelist_modenv_send_query(qstate->env->send_query));
3004 outq = (*qstate->env->send_query)(&iq->qinfo_out,
3005 iq->chase_flags | (iq->chase_to_rd?BIT_RD:0),
3006 /* unset CD if to forwarder(RD set) and not dnssec retry
3007 * (blacklist nonempty) and no trust-anchors are configured
3008 * above the qname or on the first attempt when dnssec is on */
3009 (qstate->env->cfg->disable_edns_do?0:EDNS_DO)|
3010 ((iq->chase_to_rd||(iq->chase_flags&BIT_RD)!=0)&&
3011 !qstate->blacklist&&(!iter_qname_indicates_dnssec(qstate->env,
3012 &iq->qinfo_out)||target->attempts==1)?0:BIT_CD),
3013 iq->dnssec_expected, iq->caps_fallback || is_caps_whitelisted(
3014 ie, iq), sq_check_ratelimit, &real_addr, real_addrlen,
3015 iq->dp->name, iq->dp->namelen,
3016 (iq->dp->tcp_upstream || qstate->env->cfg->tcp_upstream),
3017 (iq->dp->ssl_upstream || qstate->env->cfg->ssl_upstream),
3018 target->tls_auth_name, qstate, &sq_was_ratelimited);
3019 if(!outq) {
3020 if(sq_was_ratelimited) {
3021 lock_basic_lock(&ie->queries_ratelimit_lock);
3022 ie->num_queries_ratelimited++;
3023 lock_basic_unlock(&ie->queries_ratelimit_lock);
3024 verbose(VERB_ALGO, "query exceeded ratelimits");
3025 qstate->was_ratelimited = 1;
3026 errinf_dname(qstate, "exceeded ratelimit for zone",
3027 iq->dp->name);
3028 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3029 }
3030 log_addr(VERB_QUERY, "error sending query to auth server",
3031 &real_addr, real_addrlen);
3032 if(qstate->env->cfg->qname_minimisation)
3033 iq->minimisation_state = SKIP_MINIMISE_STATE;
3034 return next_state(iq, QUERYTARGETS_STATE);
3035 }
3036 outbound_list_insert(&iq->outlist, outq);
3037 iq->num_current_queries++;
3038 iq->sent_count++;
3039 qstate->ext_state[id] = module_wait_reply;
3040
3041 return 0;
3042 }
3043
3044 /** find NS rrset in given list */
3045 static struct ub_packed_rrset_key*
find_NS(struct reply_info * rep,size_t from,size_t to)3046 find_NS(struct reply_info* rep, size_t from, size_t to)
3047 {
3048 size_t i;
3049 for(i=from; i<to; i++) {
3050 if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NS)
3051 return rep->rrsets[i];
3052 }
3053 return NULL;
3054 }
3055
3056
3057 /**
3058 * Process the query response. All queries end up at this state first. This
3059 * process generally consists of analyzing the response and routing the
3060 * event to the next state (either bouncing it back to a request state, or
3061 * terminating the processing for this event).
3062 *
3063 * @param qstate: query state.
3064 * @param iq: iterator query state.
3065 * @param ie: iterator shared global environment.
3066 * @param id: module id.
3067 * @return true if the event requires more immediate processing, false if
3068 * not. This is generally only true when forwarding the request to
3069 * the final state (i.e., on answer).
3070 */
3071 static int
processQueryResponse(struct module_qstate * qstate,struct iter_qstate * iq,struct iter_env * ie,int id)3072 processQueryResponse(struct module_qstate* qstate, struct iter_qstate* iq,
3073 struct iter_env* ie, int id)
3074 {
3075 int dnsseclame = 0, origtypecname = 0, orig_empty_nodata_found;
3076 enum response_type type;
3077
3078 iq->num_current_queries--;
3079
3080 if(!inplace_cb_query_response_call(qstate->env, qstate, iq->response))
3081 log_err("unable to call query_response callback");
3082
3083 if(iq->response == NULL) {
3084 /* Don't increment qname when QNAME minimisation is enabled */
3085 if(qstate->env->cfg->qname_minimisation) {
3086 iq->minimisation_state = SKIP_MINIMISE_STATE;
3087 }
3088 iq->timeout_count++;
3089 iq->chase_to_rd = 0;
3090 iq->dnssec_lame_query = 0;
3091 verbose(VERB_ALGO, "query response was timeout");
3092 return next_state(iq, QUERYTARGETS_STATE);
3093 }
3094 iq->timeout_count = 0;
3095 orig_empty_nodata_found = iq->empty_nodata_found;
3096 type = response_type_from_server(
3097 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd),
3098 iq->response, &iq->qinfo_out, iq->dp, &iq->empty_nodata_found);
3099 iq->chase_to_rd = 0;
3100 /* remove TC flag, if this is erroneously set by TCP upstream */
3101 iq->response->rep->flags &= ~BIT_TC;
3102 if(orig_empty_nodata_found != iq->empty_nodata_found &&
3103 iq->empty_nodata_found < EMPTY_NODATA_RETRY_COUNT) {
3104 /* try to search at another server */
3105 if(qstate->reply) {
3106 struct delegpt_addr* a = delegpt_find_addr(
3107 iq->dp, &qstate->reply->remote_addr,
3108 qstate->reply->remote_addrlen);
3109 /* make selection disprefer it */
3110 if(a) a->lame = 1;
3111 }
3112 return next_state(iq, QUERYTARGETS_STATE);
3113 }
3114 if(type == RESPONSE_TYPE_REFERRAL && (iq->chase_flags&BIT_RD) &&
3115 !iq->auth_zone_response) {
3116 /* When forwarding (RD bit is set), we handle referrals
3117 * differently. No queries should be sent elsewhere */
3118 type = RESPONSE_TYPE_ANSWER;
3119 }
3120 if(!qstate->env->cfg->disable_dnssec_lame_check && iq->dnssec_expected
3121 && !iq->dnssec_lame_query &&
3122 !(iq->chase_flags&BIT_RD)
3123 && iq->sent_count < DNSSEC_LAME_DETECT_COUNT
3124 && type != RESPONSE_TYPE_LAME
3125 && type != RESPONSE_TYPE_REC_LAME
3126 && type != RESPONSE_TYPE_THROWAWAY
3127 && type != RESPONSE_TYPE_UNTYPED) {
3128 /* a possible answer, see if it is missing DNSSEC */
3129 /* but not when forwarding, so we dont mark fwder lame */
3130 if(!iter_msg_has_dnssec(iq->response)) {
3131 /* Mark this address as dnsseclame in this dp,
3132 * because that will make serverselection disprefer
3133 * it, but also, once it is the only final option,
3134 * use dnssec-lame-bypass if it needs to query there.*/
3135 if(qstate->reply) {
3136 struct delegpt_addr* a = delegpt_find_addr(
3137 iq->dp, &qstate->reply->remote_addr,
3138 qstate->reply->remote_addrlen);
3139 if(a) a->dnsseclame = 1;
3140 }
3141 /* test the answer is from the zone we expected,
3142 * otherwise, (due to parent,child on same server), we
3143 * might mark the server,zone lame inappropriately */
3144 if(!iter_msg_from_zone(iq->response, iq->dp, type,
3145 iq->qchase.qclass))
3146 qstate->reply = NULL;
3147 type = RESPONSE_TYPE_LAME;
3148 dnsseclame = 1;
3149 }
3150 } else iq->dnssec_lame_query = 0;
3151 /* see if referral brings us close to the target */
3152 if(type == RESPONSE_TYPE_REFERRAL) {
3153 struct ub_packed_rrset_key* ns = find_NS(
3154 iq->response->rep, iq->response->rep->an_numrrsets,
3155 iq->response->rep->an_numrrsets
3156 + iq->response->rep->ns_numrrsets);
3157 if(!ns) ns = find_NS(iq->response->rep, 0,
3158 iq->response->rep->an_numrrsets);
3159 if(!ns || !dname_strict_subdomain_c(ns->rk.dname, iq->dp->name)
3160 || !dname_subdomain_c(iq->qchase.qname, ns->rk.dname)){
3161 verbose(VERB_ALGO, "bad referral, throwaway");
3162 type = RESPONSE_TYPE_THROWAWAY;
3163 } else
3164 iter_scrub_ds(iq->response, ns, iq->dp->name);
3165 } else iter_scrub_ds(iq->response, NULL, NULL);
3166 if(type == RESPONSE_TYPE_THROWAWAY &&
3167 FLAGS_GET_RCODE(iq->response->rep->flags) == LDNS_RCODE_YXDOMAIN) {
3168 /* YXDOMAIN is a permanent error, no need to retry */
3169 type = RESPONSE_TYPE_ANSWER;
3170 }
3171 if(type == RESPONSE_TYPE_CNAME)
3172 origtypecname = 1;
3173 if(type == RESPONSE_TYPE_CNAME && iq->response->rep->an_numrrsets >= 1
3174 && ntohs(iq->response->rep->rrsets[0]->rk.type) == LDNS_RR_TYPE_DNAME) {
3175 uint8_t* sname = NULL;
3176 size_t snamelen = 0;
3177 get_cname_target(iq->response->rep->rrsets[0], &sname,
3178 &snamelen);
3179 if(snamelen && dname_subdomain_c(sname, iq->response->rep->rrsets[0]->rk.dname)) {
3180 /* DNAME to a subdomain loop; do not recurse */
3181 type = RESPONSE_TYPE_ANSWER;
3182 }
3183 }
3184 if(type == RESPONSE_TYPE_CNAME &&
3185 iq->qchase.qtype == LDNS_RR_TYPE_CNAME &&
3186 iq->minimisation_state == MINIMISE_STATE &&
3187 query_dname_compare(iq->qchase.qname, iq->qinfo_out.qname) == 0) {
3188 /* The minimised query for full QTYPE and hidden QTYPE can be
3189 * classified as CNAME response type, even when the original
3190 * QTYPE=CNAME. This should be treated as answer response type.
3191 */
3192 type = RESPONSE_TYPE_ANSWER;
3193 }
3194
3195 /* handle each of the type cases */
3196 if(type == RESPONSE_TYPE_ANSWER) {
3197 /* ANSWER type responses terminate the query algorithm,
3198 * so they sent on their */
3199 if(verbosity >= VERB_DETAIL) {
3200 verbose(VERB_DETAIL, "query response was %s",
3201 FLAGS_GET_RCODE(iq->response->rep->flags)
3202 ==LDNS_RCODE_NXDOMAIN?"NXDOMAIN ANSWER":
3203 (iq->response->rep->an_numrrsets?"ANSWER":
3204 "nodata ANSWER"));
3205 }
3206 /* if qtype is DS, check we have the right level of answer,
3207 * like grandchild answer but we need the middle, reject it */
3208 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
3209 && !(iq->chase_flags&BIT_RD)
3210 && iter_ds_toolow(iq->response, iq->dp)
3211 && iter_dp_cangodown(&iq->qchase, iq->dp)) {
3212 /* close down outstanding requests to be discarded */
3213 outbound_list_clear(&iq->outlist);
3214 iq->num_current_queries = 0;
3215 fptr_ok(fptr_whitelist_modenv_detach_subs(
3216 qstate->env->detach_subs));
3217 (*qstate->env->detach_subs)(qstate);
3218 iq->num_target_queries = 0;
3219 return processDSNSFind(qstate, iq, id);
3220 }
3221 if(!qstate->no_cache_store)
3222 iter_dns_store(qstate->env, &iq->response->qinfo,
3223 iq->response->rep,
3224 iq->qchase.qtype != iq->response->qinfo.qtype,
3225 qstate->prefetch_leeway,
3226 iq->dp&&iq->dp->has_parent_side_NS,
3227 qstate->region, qstate->query_flags,
3228 qstate->qstarttime);
3229 /* close down outstanding requests to be discarded */
3230 outbound_list_clear(&iq->outlist);
3231 iq->num_current_queries = 0;
3232 fptr_ok(fptr_whitelist_modenv_detach_subs(
3233 qstate->env->detach_subs));
3234 (*qstate->env->detach_subs)(qstate);
3235 iq->num_target_queries = 0;
3236 if(qstate->reply)
3237 sock_list_insert(&qstate->reply_origin,
3238 &qstate->reply->remote_addr,
3239 qstate->reply->remote_addrlen, qstate->region);
3240 if(iq->minimisation_state != DONOT_MINIMISE_STATE
3241 && !(iq->chase_flags & BIT_RD)) {
3242 if(FLAGS_GET_RCODE(iq->response->rep->flags) !=
3243 LDNS_RCODE_NOERROR) {
3244 if(qstate->env->cfg->qname_minimisation_strict) {
3245 if(FLAGS_GET_RCODE(iq->response->rep->flags) ==
3246 LDNS_RCODE_NXDOMAIN) {
3247 iter_scrub_nxdomain(iq->response);
3248 return final_state(iq);
3249 }
3250 return error_response(qstate, id,
3251 LDNS_RCODE_SERVFAIL);
3252 }
3253 /* Best effort qname-minimisation.
3254 * Stop minimising and send full query when
3255 * RCODE is not NOERROR. */
3256 iq->minimisation_state = DONOT_MINIMISE_STATE;
3257 }
3258 if(FLAGS_GET_RCODE(iq->response->rep->flags) ==
3259 LDNS_RCODE_NXDOMAIN && !origtypecname) {
3260 /* Stop resolving when NXDOMAIN is DNSSEC
3261 * signed. Based on assumption that nameservers
3262 * serving signed zones do not return NXDOMAIN
3263 * for empty-non-terminals. */
3264 /* If this response is actually a CNAME type,
3265 * the nxdomain rcode may not be for the qname,
3266 * and so it is not the final response. */
3267 if(iq->dnssec_expected)
3268 return final_state(iq);
3269 /* Make subrequest to validate intermediate
3270 * NXDOMAIN if harden-below-nxdomain is
3271 * enabled. */
3272 if(qstate->env->cfg->harden_below_nxdomain &&
3273 qstate->env->need_to_validate) {
3274 struct module_qstate* subq = NULL;
3275 log_query_info(VERB_QUERY,
3276 "schedule NXDOMAIN validation:",
3277 &iq->response->qinfo);
3278 if(!generate_sub_request(
3279 iq->response->qinfo.qname,
3280 iq->response->qinfo.qname_len,
3281 iq->response->qinfo.qtype,
3282 iq->response->qinfo.qclass,
3283 qstate, id, iq,
3284 INIT_REQUEST_STATE,
3285 FINISHED_STATE, &subq, 1, 1))
3286 verbose(VERB_ALGO,
3287 "could not validate NXDOMAIN "
3288 "response");
3289 }
3290 }
3291 return next_state(iq, QUERYTARGETS_STATE);
3292 }
3293 return final_state(iq);
3294 } else if(type == RESPONSE_TYPE_REFERRAL) {
3295 struct delegpt* old_dp = NULL;
3296 /* REFERRAL type responses get a reset of the
3297 * delegation point, and back to the QUERYTARGETS_STATE. */
3298 verbose(VERB_DETAIL, "query response was REFERRAL");
3299
3300 /* if hardened, only store referral if we asked for it */
3301 if(!qstate->no_cache_store &&
3302 (!qstate->env->cfg->harden_referral_path ||
3303 ( qstate->qinfo.qtype == LDNS_RR_TYPE_NS
3304 && (qstate->query_flags&BIT_RD)
3305 && !(qstate->query_flags&BIT_CD)
3306 /* we know that all other NS rrsets are scrubbed
3307 * away, thus on referral only one is left.
3308 * see if that equals the query name... */
3309 && ( /* auth section, but sometimes in answer section*/
3310 reply_find_rrset_section_ns(iq->response->rep,
3311 iq->qchase.qname, iq->qchase.qname_len,
3312 LDNS_RR_TYPE_NS, iq->qchase.qclass)
3313 || reply_find_rrset_section_an(iq->response->rep,
3314 iq->qchase.qname, iq->qchase.qname_len,
3315 LDNS_RR_TYPE_NS, iq->qchase.qclass)
3316 )
3317 ))) {
3318 /* Store the referral under the current query */
3319 /* no prefetch-leeway, since its not the answer */
3320 iter_dns_store(qstate->env, &iq->response->qinfo,
3321 iq->response->rep, 1, 0, 0, NULL, 0,
3322 qstate->qstarttime);
3323 if(iq->store_parent_NS)
3324 iter_store_parentside_NS(qstate->env,
3325 iq->response->rep);
3326 if(qstate->env->neg_cache)
3327 val_neg_addreferral(qstate->env->neg_cache,
3328 iq->response->rep, iq->dp->name);
3329 }
3330 /* store parent-side-in-zone-glue, if directly queried for */
3331 if(!qstate->no_cache_store && iq->query_for_pside_glue
3332 && !iq->pside_glue) {
3333 iq->pside_glue = reply_find_rrset(iq->response->rep,
3334 iq->qchase.qname, iq->qchase.qname_len,
3335 iq->qchase.qtype, iq->qchase.qclass);
3336 if(iq->pside_glue) {
3337 log_rrset_key(VERB_ALGO, "found parent-side "
3338 "glue", iq->pside_glue);
3339 iter_store_parentside_rrset(qstate->env,
3340 iq->pside_glue);
3341 }
3342 }
3343
3344 /* Reset the event state, setting the current delegation
3345 * point to the referral. */
3346 iq->deleg_msg = iq->response;
3347 /* Keep current delegation point for label comparison */
3348 old_dp = iq->dp;
3349 iq->dp = delegpt_from_message(iq->response, qstate->region);
3350 if (qstate->env->cfg->qname_minimisation)
3351 iq->minimisation_state = INIT_MINIMISE_STATE;
3352 if(!iq->dp) {
3353 errinf(qstate, "malloc failure, for delegation point");
3354 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3355 }
3356 if(old_dp->namelabs + 1 < iq->dp->namelabs) {
3357 /* We got a grandchild delegation (more than one label
3358 * difference) than expected. Check for in-between
3359 * delegations in the cache and remove them.
3360 * They could prove problematic when they expire
3361 * and rrset_expired_above() encounters them during
3362 * delegation cache lookups. */
3363 uint8_t* qname = iq->dp->name;
3364 size_t qnamelen = iq->dp->namelen;
3365 rrset_cache_remove_above(qstate->env->rrset_cache,
3366 &qname, &qnamelen, LDNS_RR_TYPE_NS,
3367 iq->qchase.qclass, *qstate->env->now,
3368 old_dp->name, old_dp->namelen);
3369 }
3370 if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
3371 qstate->region, iq->dp)) {
3372 errinf(qstate, "malloc failure, copy extra info into delegation point");
3373 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3374 }
3375 if(iq->store_parent_NS && query_dname_compare(iq->dp->name,
3376 iq->store_parent_NS->name) == 0)
3377 iter_merge_retry_counts(iq->dp, iq->store_parent_NS,
3378 ie->outbound_msg_retry);
3379 delegpt_log(VERB_ALGO, iq->dp);
3380 /* Count this as a referral. */
3381 iq->referral_count++;
3382 iq->sent_count = 0;
3383 iq->dp_target_count = 0;
3384 /* see if the next dp is a trust anchor, or a DS was sent
3385 * along, indicating dnssec is expected for next zone */
3386 iq->dnssec_expected = iter_indicates_dnssec(qstate->env,
3387 iq->dp, iq->response, iq->qchase.qclass);
3388 /* if dnssec, validating then also fetch the key for the DS */
3389 if(iq->dnssec_expected && qstate->env->cfg->prefetch_key &&
3390 !(qstate->query_flags&BIT_CD))
3391 generate_dnskey_prefetch(qstate, iq, id);
3392
3393 /* spawn off NS and addr to auth servers for the NS we just
3394 * got in the referral. This gets authoritative answer
3395 * (answer section trust level) rrset.
3396 * right after, we detach the subs, answer goes to cache. */
3397 if(qstate->env->cfg->harden_referral_path)
3398 generate_ns_check(qstate, iq, id);
3399
3400 /* stop current outstanding queries.
3401 * FIXME: should the outstanding queries be waited for and
3402 * handled? Say by a subquery that inherits the outbound_entry.
3403 */
3404 outbound_list_clear(&iq->outlist);
3405 iq->num_current_queries = 0;
3406 fptr_ok(fptr_whitelist_modenv_detach_subs(
3407 qstate->env->detach_subs));
3408 (*qstate->env->detach_subs)(qstate);
3409 iq->num_target_queries = 0;
3410 iq->response = NULL;
3411 iq->fail_addr_type = 0;
3412 verbose(VERB_ALGO, "cleared outbound list for next round");
3413 return next_state(iq, QUERYTARGETS_STATE);
3414 } else if(type == RESPONSE_TYPE_CNAME) {
3415 uint8_t* sname = NULL;
3416 size_t snamelen = 0;
3417 /* CNAME type responses get a query restart (i.e., get a
3418 * reset of the query state and go back to INIT_REQUEST_STATE).
3419 */
3420 verbose(VERB_DETAIL, "query response was CNAME");
3421 if(verbosity >= VERB_ALGO)
3422 log_dns_msg("cname msg", &iq->response->qinfo,
3423 iq->response->rep);
3424 /* if qtype is DS, check we have the right level of answer,
3425 * like grandchild answer but we need the middle, reject it */
3426 if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
3427 && !(iq->chase_flags&BIT_RD)
3428 && iter_ds_toolow(iq->response, iq->dp)
3429 && iter_dp_cangodown(&iq->qchase, iq->dp)) {
3430 outbound_list_clear(&iq->outlist);
3431 iq->num_current_queries = 0;
3432 fptr_ok(fptr_whitelist_modenv_detach_subs(
3433 qstate->env->detach_subs));
3434 (*qstate->env->detach_subs)(qstate);
3435 iq->num_target_queries = 0;
3436 return processDSNSFind(qstate, iq, id);
3437 }
3438 /* Process the CNAME response. */
3439 if(!handle_cname_response(qstate, iq, iq->response,
3440 &sname, &snamelen)) {
3441 errinf(qstate, "malloc failure, CNAME info");
3442 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3443 }
3444 /* cache the CNAME response under the current query */
3445 /* NOTE : set referral=1, so that rrsets get stored but not
3446 * the partial query answer (CNAME only). */
3447 /* prefetchleeway applied because this updates answer parts */
3448 if(!qstate->no_cache_store)
3449 iter_dns_store(qstate->env, &iq->response->qinfo,
3450 iq->response->rep, 1, qstate->prefetch_leeway,
3451 iq->dp&&iq->dp->has_parent_side_NS, NULL,
3452 qstate->query_flags, qstate->qstarttime);
3453 /* set the current request's qname to the new value. */
3454 iq->qchase.qname = sname;
3455 iq->qchase.qname_len = snamelen;
3456 if(qstate->env->auth_zones) {
3457 /* apply rpz qname triggers after cname */
3458 struct dns_msg* forged_response =
3459 rpz_callback_from_iterator_cname(qstate, iq);
3460 int count = 0;
3461 while(forged_response && reply_find_rrset_section_an(
3462 forged_response->rep, iq->qchase.qname,
3463 iq->qchase.qname_len, LDNS_RR_TYPE_CNAME,
3464 iq->qchase.qclass) &&
3465 iq->qchase.qtype != LDNS_RR_TYPE_CNAME &&
3466 count++ < ie->max_query_restarts) {
3467 /* another cname to follow */
3468 if(!handle_cname_response(qstate, iq, forged_response,
3469 &sname, &snamelen)) {
3470 errinf(qstate, "malloc failure, CNAME info");
3471 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3472 }
3473 iq->qchase.qname = sname;
3474 iq->qchase.qname_len = snamelen;
3475 forged_response =
3476 rpz_callback_from_iterator_cname(qstate, iq);
3477 }
3478 if(forged_response != NULL) {
3479 qstate->ext_state[id] = module_finished;
3480 qstate->return_rcode = LDNS_RCODE_NOERROR;
3481 qstate->return_msg = forged_response;
3482 iq->response = forged_response;
3483 next_state(iq, FINISHED_STATE);
3484 if(!iter_prepend(iq, qstate->return_msg, qstate->region)) {
3485 log_err("rpz: after cname, prepend rrsets: out of memory");
3486 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3487 }
3488 qstate->return_msg->qinfo = qstate->qinfo;
3489 return 0;
3490 }
3491 }
3492 /* Clear the query state, since this is a query restart. */
3493 iq->deleg_msg = NULL;
3494 iq->dp = NULL;
3495 iq->dsns_point = NULL;
3496 iq->auth_zone_response = 0;
3497 iq->sent_count = 0;
3498 iq->dp_target_count = 0;
3499 if(iq->minimisation_state != MINIMISE_STATE)
3500 /* Only count as query restart when it is not an extra
3501 * query as result of qname minimisation. */
3502 iq->query_restart_count++;
3503 if(qstate->env->cfg->qname_minimisation)
3504 iq->minimisation_state = INIT_MINIMISE_STATE;
3505
3506 /* stop current outstanding queries.
3507 * FIXME: should the outstanding queries be waited for and
3508 * handled? Say by a subquery that inherits the outbound_entry.
3509 */
3510 outbound_list_clear(&iq->outlist);
3511 iq->num_current_queries = 0;
3512 fptr_ok(fptr_whitelist_modenv_detach_subs(
3513 qstate->env->detach_subs));
3514 (*qstate->env->detach_subs)(qstate);
3515 iq->num_target_queries = 0;
3516 if(qstate->reply)
3517 sock_list_insert(&qstate->reply_origin,
3518 &qstate->reply->remote_addr,
3519 qstate->reply->remote_addrlen, qstate->region);
3520 verbose(VERB_ALGO, "cleared outbound list for query restart");
3521 /* go to INIT_REQUEST_STATE for new qname. */
3522 return next_state(iq, INIT_REQUEST_STATE);
3523 } else if(type == RESPONSE_TYPE_LAME) {
3524 /* Cache the LAMEness. */
3525 verbose(VERB_DETAIL, "query response was %sLAME",
3526 dnsseclame?"DNSSEC ":"");
3527 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) {
3528 log_err("mark lame: mismatch in qname and dpname");
3529 /* throwaway this reply below */
3530 } else if(qstate->reply) {
3531 /* need addr for lameness cache, but we may have
3532 * gotten this from cache, so test to be sure */
3533 if(!infra_set_lame(qstate->env->infra_cache,
3534 &qstate->reply->remote_addr,
3535 qstate->reply->remote_addrlen,
3536 iq->dp->name, iq->dp->namelen,
3537 *qstate->env->now, dnsseclame, 0,
3538 iq->qchase.qtype))
3539 log_err("mark host lame: out of memory");
3540 }
3541 } else if(type == RESPONSE_TYPE_REC_LAME) {
3542 /* Cache the LAMEness. */
3543 verbose(VERB_DETAIL, "query response REC_LAME: "
3544 "recursive but not authoritative server");
3545 if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) {
3546 log_err("mark rec_lame: mismatch in qname and dpname");
3547 /* throwaway this reply below */
3548 } else if(qstate->reply) {
3549 /* need addr for lameness cache, but we may have
3550 * gotten this from cache, so test to be sure */
3551 verbose(VERB_DETAIL, "mark as REC_LAME");
3552 if(!infra_set_lame(qstate->env->infra_cache,
3553 &qstate->reply->remote_addr,
3554 qstate->reply->remote_addrlen,
3555 iq->dp->name, iq->dp->namelen,
3556 *qstate->env->now, 0, 1, iq->qchase.qtype))
3557 log_err("mark host lame: out of memory");
3558 }
3559 } else if(type == RESPONSE_TYPE_THROWAWAY) {
3560 /* LAME and THROWAWAY responses are handled the same way.
3561 * In this case, the event is just sent directly back to
3562 * the QUERYTARGETS_STATE without resetting anything,
3563 * because, clearly, the next target must be tried. */
3564 verbose(VERB_DETAIL, "query response was THROWAWAY");
3565 } else {
3566 log_warn("A query response came back with an unknown type: %d",
3567 (int)type);
3568 }
3569
3570 /* LAME, THROWAWAY and "unknown" all end up here.
3571 * Recycle to the QUERYTARGETS state to hopefully try a
3572 * different target. */
3573 if (qstate->env->cfg->qname_minimisation &&
3574 !qstate->env->cfg->qname_minimisation_strict)
3575 iq->minimisation_state = DONOT_MINIMISE_STATE;
3576 if(iq->auth_zone_response) {
3577 /* can we fallback? */
3578 iq->auth_zone_response = 0;
3579 if(!auth_zones_can_fallback(qstate->env->auth_zones,
3580 iq->dp->name, iq->dp->namelen, qstate->qinfo.qclass)) {
3581 verbose(VERB_ALGO, "auth zone response bad, and no"
3582 " fallback possible, servfail");
3583 errinf_dname(qstate, "response is bad, no fallback, "
3584 "for auth zone", iq->dp->name);
3585 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
3586 }
3587 verbose(VERB_ALGO, "auth zone response was bad, "
3588 "fallback enabled");
3589 iq->auth_zone_avoid = 1;
3590 if(iq->dp->auth_dp) {
3591 /* we are using a dp for the auth zone, with no
3592 * nameservers, get one first */
3593 iq->dp = NULL;
3594 return next_state(iq, INIT_REQUEST_STATE);
3595 }
3596 }
3597 return next_state(iq, QUERYTARGETS_STATE);
3598 }
3599
3600 /**
3601 * Return priming query results to interested super querystates.
3602 *
3603 * Sets the delegation point and delegation message (not nonRD queries).
3604 * This is a callback from walk_supers.
3605 *
3606 * @param qstate: priming query state that finished.
3607 * @param id: module id.
3608 * @param forq: the qstate for which priming has been done.
3609 */
3610 static void
prime_supers(struct module_qstate * qstate,int id,struct module_qstate * forq)3611 prime_supers(struct module_qstate* qstate, int id, struct module_qstate* forq)
3612 {
3613 struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
3614 struct delegpt* dp = NULL;
3615
3616 log_assert(qstate->is_priming || foriq->wait_priming_stub);
3617 log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR);
3618 /* Convert our response to a delegation point */
3619 dp = delegpt_from_message(qstate->return_msg, forq->region);
3620 if(!dp) {
3621 /* if there is no convertible delegation point, then
3622 * the ANSWER type was (presumably) a negative answer. */
3623 verbose(VERB_ALGO, "prime response was not a positive "
3624 "ANSWER; failing");
3625 foriq->dp = NULL;
3626 foriq->state = QUERYTARGETS_STATE;
3627 return;
3628 }
3629
3630 log_query_info(VERB_DETAIL, "priming successful for", &qstate->qinfo);
3631 delegpt_log(VERB_ALGO, dp);
3632 foriq->dp = dp;
3633 foriq->deleg_msg = dns_copy_msg(qstate->return_msg, forq->region);
3634 if(!foriq->deleg_msg) {
3635 log_err("copy prime response: out of memory");
3636 foriq->dp = NULL;
3637 foriq->state = QUERYTARGETS_STATE;
3638 return;
3639 }
3640
3641 /* root priming responses go to init stage 2, priming stub
3642 * responses to to stage 3. */
3643 if(foriq->wait_priming_stub) {
3644 foriq->state = INIT_REQUEST_3_STATE;
3645 foriq->wait_priming_stub = 0;
3646 } else foriq->state = INIT_REQUEST_2_STATE;
3647 /* because we are finished, the parent will be reactivated */
3648 }
3649
3650 /**
3651 * This handles the response to a priming query. This is used to handle both
3652 * root and stub priming responses. This is basically the equivalent of the
3653 * QUERY_RESP_STATE, but will not handle CNAME responses and will treat
3654 * REFERRALs as ANSWERS. It will also update and reactivate the originating
3655 * event.
3656 *
3657 * @param qstate: query state.
3658 * @param id: module id.
3659 * @return true if the event needs more immediate processing, false if not.
3660 * This state always returns false.
3661 */
3662 static int
processPrimeResponse(struct module_qstate * qstate,int id)3663 processPrimeResponse(struct module_qstate* qstate, int id)
3664 {
3665 struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3666 enum response_type type;
3667 iq->response->rep->flags &= ~(BIT_RD|BIT_RA); /* ignore rec-lame */
3668 type = response_type_from_server(
3669 (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd),
3670 iq->response, &iq->qchase, iq->dp, NULL);
3671 if(type == RESPONSE_TYPE_ANSWER) {
3672 qstate->return_rcode = LDNS_RCODE_NOERROR;
3673 qstate->return_msg = iq->response;
3674 } else {
3675 errinf(qstate, "prime response did not get an answer");
3676 errinf_dname(qstate, "for", qstate->qinfo.qname);
3677 qstate->return_rcode = LDNS_RCODE_SERVFAIL;
3678 qstate->return_msg = NULL;
3679 }
3680
3681 /* validate the root or stub after priming (if enabled).
3682 * This is the same query as the prime query, but with validation.
3683 * Now that we are primed, the additional queries that validation
3684 * may need can be resolved. */
3685 if(qstate->env->cfg->harden_referral_path) {
3686 struct module_qstate* subq = NULL;
3687 log_nametypeclass(VERB_ALGO, "schedule prime validation",
3688 qstate->qinfo.qname, qstate->qinfo.qtype,
3689 qstate->qinfo.qclass);
3690 if(!generate_sub_request(qstate->qinfo.qname,
3691 qstate->qinfo.qname_len, qstate->qinfo.qtype,
3692 qstate->qinfo.qclass, qstate, id, iq,
3693 INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1, 0)) {
3694 verbose(VERB_ALGO, "could not generate prime check");
3695 }
3696 generate_a_aaaa_check(qstate, iq, id);
3697 }
3698
3699 /* This event is finished. */
3700 qstate->ext_state[id] = module_finished;
3701 return 0;
3702 }
3703
3704 /**
3705 * Do final processing on responses to target queries. Events reach this
3706 * state after the iterative resolution algorithm terminates. This state is
3707 * responsible for reactivating the original event, and housekeeping related
3708 * to received target responses (caching, updating the current delegation
3709 * point, etc).
3710 * Callback from walk_supers for every super state that is interested in
3711 * the results from this query.
3712 *
3713 * @param qstate: query state.
3714 * @param id: module id.
3715 * @param forq: super query state.
3716 */
3717 static void
processTargetResponse(struct module_qstate * qstate,int id,struct module_qstate * forq)3718 processTargetResponse(struct module_qstate* qstate, int id,
3719 struct module_qstate* forq)
3720 {
3721 struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
3722 struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3723 struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
3724 struct ub_packed_rrset_key* rrset;
3725 struct delegpt_ns* dpns;
3726 log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR);
3727
3728 foriq->state = QUERYTARGETS_STATE;
3729 log_query_info(VERB_ALGO, "processTargetResponse", &qstate->qinfo);
3730 log_query_info(VERB_ALGO, "processTargetResponse super", &forq->qinfo);
3731
3732 /* Tell the originating event that this target query has finished
3733 * (regardless if it succeeded or not). */
3734 foriq->num_target_queries--;
3735
3736 /* check to see if parent event is still interested (in orig name). */
3737 if(!foriq->dp) {
3738 verbose(VERB_ALGO, "subq: parent not interested, was reset");
3739 return; /* not interested anymore */
3740 }
3741 dpns = delegpt_find_ns(foriq->dp, qstate->qinfo.qname,
3742 qstate->qinfo.qname_len);
3743 if(!dpns) {
3744 /* If not interested, just stop processing this event */
3745 verbose(VERB_ALGO, "subq: parent not interested anymore");
3746 /* could be because parent was jostled out of the cache,
3747 and a new identical query arrived, that does not want it*/
3748 return;
3749 }
3750
3751 /* if iq->query_for_pside_glue then add the pside_glue (marked lame) */
3752 if(iq->pside_glue) {
3753 /* if the pside_glue is NULL, then it could not be found,
3754 * the done_pside is already set when created and a cache
3755 * entry created in processFinished so nothing to do here */
3756 log_rrset_key(VERB_ALGO, "add parentside glue to dp",
3757 iq->pside_glue);
3758 if(!delegpt_add_rrset(foriq->dp, forq->region,
3759 iq->pside_glue, 1, NULL))
3760 log_err("out of memory adding pside glue");
3761 }
3762
3763 /* This response is relevant to the current query, so we
3764 * add (attempt to add, anyway) this target(s) and reactivate
3765 * the original event.
3766 * NOTE: we could only look for the AnswerRRset if the
3767 * response type was ANSWER. */
3768 rrset = reply_find_answer_rrset(&iq->qchase, qstate->return_msg->rep);
3769 if(rrset) {
3770 int additions = 0;
3771 /* if CNAMEs have been followed - add new NS to delegpt. */
3772 /* BTW. RFC 1918 says NS should not have got CNAMEs. Robust. */
3773 if(!delegpt_find_ns(foriq->dp, rrset->rk.dname,
3774 rrset->rk.dname_len)) {
3775 /* if dpns->lame then set newcname ns lame too */
3776 if(!delegpt_add_ns(foriq->dp, forq->region,
3777 rrset->rk.dname, dpns->lame, dpns->tls_auth_name,
3778 dpns->port))
3779 log_err("out of memory adding cnamed-ns");
3780 }
3781 /* if dpns->lame then set the address(es) lame too */
3782 if(!delegpt_add_rrset(foriq->dp, forq->region, rrset,
3783 dpns->lame, &additions))
3784 log_err("out of memory adding targets");
3785 if(!additions) {
3786 /* no new addresses, increase the nxns counter, like
3787 * this could be a list of wildcards with no new
3788 * addresses */
3789 target_count_increase_nx(foriq, 1);
3790 }
3791 verbose(VERB_ALGO, "added target response");
3792 delegpt_log(VERB_ALGO, foriq->dp);
3793 } else {
3794 verbose(VERB_ALGO, "iterator TargetResponse failed");
3795 delegpt_mark_neg(dpns, qstate->qinfo.qtype);
3796 if((dpns->got4 == 2 || (!ie->supports_ipv4 && !ie->use_nat64)) &&
3797 (dpns->got6 == 2 || !ie->supports_ipv6)) {
3798 dpns->resolved = 1; /* fail the target */
3799 /* do not count cached answers */
3800 if(qstate->reply_origin && qstate->reply_origin->len != 0) {
3801 target_count_increase_nx(foriq, 1);
3802 }
3803 }
3804 }
3805 }
3806
3807 /**
3808 * Process response for DS NS Find queries, that attempt to find the delegation
3809 * point where we ask the DS query from.
3810 *
3811 * @param qstate: query state.
3812 * @param id: module id.
3813 * @param forq: super query state.
3814 */
3815 static void
processDSNSResponse(struct module_qstate * qstate,int id,struct module_qstate * forq)3816 processDSNSResponse(struct module_qstate* qstate, int id,
3817 struct module_qstate* forq)
3818 {
3819 struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
3820
3821 /* if the finished (iq->response) query has no NS set: continue
3822 * up to look for the right dp; nothing to change, do DPNSstate */
3823 if(qstate->return_rcode != LDNS_RCODE_NOERROR)
3824 return; /* seek further */
3825 /* find the NS RRset (without allowing CNAMEs) */
3826 if(!reply_find_rrset(qstate->return_msg->rep, qstate->qinfo.qname,
3827 qstate->qinfo.qname_len, LDNS_RR_TYPE_NS,
3828 qstate->qinfo.qclass)){
3829 return; /* seek further */
3830 }
3831
3832 /* else, store as DP and continue at querytargets */
3833 foriq->state = QUERYTARGETS_STATE;
3834 foriq->dp = delegpt_from_message(qstate->return_msg, forq->region);
3835 if(!foriq->dp) {
3836 log_err("out of memory in dsns dp alloc");
3837 errinf(qstate, "malloc failure, in DS search");
3838 return; /* dp==NULL in QUERYTARGETS makes SERVFAIL */
3839 }
3840 /* success, go query the querytargets in the new dp (and go down) */
3841 }
3842
3843 /**
3844 * Process response for qclass=ANY queries for a particular class.
3845 * Append to result or error-exit.
3846 *
3847 * @param qstate: query state.
3848 * @param id: module id.
3849 * @param forq: super query state.
3850 */
3851 static void
processClassResponse(struct module_qstate * qstate,int id,struct module_qstate * forq)3852 processClassResponse(struct module_qstate* qstate, int id,
3853 struct module_qstate* forq)
3854 {
3855 struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
3856 struct dns_msg* from = qstate->return_msg;
3857 log_query_info(VERB_ALGO, "processClassResponse", &qstate->qinfo);
3858 log_query_info(VERB_ALGO, "processClassResponse super", &forq->qinfo);
3859 if(qstate->return_rcode != LDNS_RCODE_NOERROR) {
3860 /* cause servfail for qclass ANY query */
3861 foriq->response = NULL;
3862 foriq->state = FINISHED_STATE;
3863 return;
3864 }
3865 /* append result */
3866 if(!foriq->response) {
3867 /* allocate the response: copy RCODE, sec_state */
3868 foriq->response = dns_copy_msg(from, forq->region);
3869 if(!foriq->response) {
3870 log_err("malloc failed for qclass ANY response");
3871 foriq->state = FINISHED_STATE;
3872 return;
3873 }
3874 foriq->response->qinfo.qclass = forq->qinfo.qclass;
3875 /* qclass ANY does not receive the AA flag on replies */
3876 foriq->response->rep->authoritative = 0;
3877 } else {
3878 struct dns_msg* to = foriq->response;
3879 /* add _from_ this response _to_ existing collection */
3880 /* if there are records, copy RCODE */
3881 /* lower sec_state if this message is lower */
3882 if(from->rep->rrset_count != 0) {
3883 size_t n = from->rep->rrset_count+to->rep->rrset_count;
3884 struct ub_packed_rrset_key** dest, **d;
3885 /* copy appropriate rcode */
3886 to->rep->flags = from->rep->flags;
3887 /* copy rrsets */
3888 if(from->rep->rrset_count > RR_COUNT_MAX ||
3889 to->rep->rrset_count > RR_COUNT_MAX) {
3890 log_err("malloc failed (too many rrsets) in collect ANY");
3891 foriq->state = FINISHED_STATE;
3892 return; /* integer overflow protection */
3893 }
3894 dest = regional_alloc(forq->region, sizeof(dest[0])*n);
3895 if(!dest) {
3896 log_err("malloc failed in collect ANY");
3897 foriq->state = FINISHED_STATE;
3898 return;
3899 }
3900 d = dest;
3901 /* copy AN */
3902 memcpy(dest, to->rep->rrsets, to->rep->an_numrrsets
3903 * sizeof(dest[0]));
3904 dest += to->rep->an_numrrsets;
3905 memcpy(dest, from->rep->rrsets, from->rep->an_numrrsets
3906 * sizeof(dest[0]));
3907 dest += from->rep->an_numrrsets;
3908 /* copy NS */
3909 memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets,
3910 to->rep->ns_numrrsets * sizeof(dest[0]));
3911 dest += to->rep->ns_numrrsets;
3912 memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets,
3913 from->rep->ns_numrrsets * sizeof(dest[0]));
3914 dest += from->rep->ns_numrrsets;
3915 /* copy AR */
3916 memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets+
3917 to->rep->ns_numrrsets,
3918 to->rep->ar_numrrsets * sizeof(dest[0]));
3919 dest += to->rep->ar_numrrsets;
3920 memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets+
3921 from->rep->ns_numrrsets,
3922 from->rep->ar_numrrsets * sizeof(dest[0]));
3923 /* update counts */
3924 to->rep->rrsets = d;
3925 to->rep->an_numrrsets += from->rep->an_numrrsets;
3926 to->rep->ns_numrrsets += from->rep->ns_numrrsets;
3927 to->rep->ar_numrrsets += from->rep->ar_numrrsets;
3928 to->rep->rrset_count = n;
3929 }
3930 if(from->rep->security < to->rep->security) /* lowest sec */
3931 to->rep->security = from->rep->security;
3932 if(from->rep->qdcount != 0) /* insert qd if appropriate */
3933 to->rep->qdcount = from->rep->qdcount;
3934 if(from->rep->ttl < to->rep->ttl) /* use smallest TTL */
3935 to->rep->ttl = from->rep->ttl;
3936 if(from->rep->prefetch_ttl < to->rep->prefetch_ttl)
3937 to->rep->prefetch_ttl = from->rep->prefetch_ttl;
3938 if(from->rep->serve_expired_ttl < to->rep->serve_expired_ttl)
3939 to->rep->serve_expired_ttl = from->rep->serve_expired_ttl;
3940 }
3941 /* are we done? */
3942 foriq->num_current_queries --;
3943 if(foriq->num_current_queries == 0)
3944 foriq->state = FINISHED_STATE;
3945 }
3946
3947 /**
3948 * Collect class ANY responses and make them into one response. This
3949 * state is started and it creates queries for all classes (that have
3950 * root hints). The answers are then collected.
3951 *
3952 * @param qstate: query state.
3953 * @param id: module id.
3954 * @return true if the event needs more immediate processing, false if not.
3955 */
3956 static int
processCollectClass(struct module_qstate * qstate,int id)3957 processCollectClass(struct module_qstate* qstate, int id)
3958 {
3959 struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
3960 struct module_qstate* subq;
3961 /* If qchase.qclass == 0 then send out queries for all classes.
3962 * Otherwise, do nothing (wait for all answers to arrive and the
3963 * processClassResponse to put them together, and that moves us
3964 * towards the Finished state when done. */
3965 if(iq->qchase.qclass == 0) {
3966 uint16_t c = 0;
3967 iq->qchase.qclass = LDNS_RR_CLASS_ANY;
3968 while(iter_get_next_root(qstate->env->hints,
3969 qstate->env->fwds, &c)) {
3970 /* generate query for this class */
3971 log_nametypeclass(VERB_ALGO, "spawn collect query",
3972 qstate->qinfo.qname, qstate->qinfo.qtype, c);
3973 if(!generate_sub_request(qstate->qinfo.qname,
3974 qstate->qinfo.qname_len, qstate->qinfo.qtype,
3975 c, qstate, id, iq, INIT_REQUEST_STATE,
3976 FINISHED_STATE, &subq,
3977 (int)!(qstate->query_flags&BIT_CD), 0)) {
3978 errinf(qstate, "could not generate class ANY"
3979 " lookup query");
3980 return error_response(qstate, id,
3981 LDNS_RCODE_SERVFAIL);
3982 }
3983 /* ignore subq, no special init required */
3984 iq->num_current_queries ++;
3985 if(c == 0xffff)
3986 break;
3987 else c++;
3988 }
3989 /* if no roots are configured at all, return */
3990 if(iq->num_current_queries == 0) {
3991 verbose(VERB_ALGO, "No root hints or fwds, giving up "
3992 "on qclass ANY");
3993 return error_response(qstate, id, LDNS_RCODE_REFUSED);
3994 }
3995 /* return false, wait for queries to return */
3996 }
3997 /* if woke up here because of an answer, wait for more answers */
3998 return 0;
3999 }
4000
4001 /**
4002 * This handles the final state for first-tier responses (i.e., responses to
4003 * externally generated queries).
4004 *
4005 * @param qstate: query state.
4006 * @param iq: iterator query state.
4007 * @param id: module id.
4008 * @return true if the event needs more processing, false if not. Since this
4009 * is the final state for an event, it always returns false.
4010 */
4011 static int
processFinished(struct module_qstate * qstate,struct iter_qstate * iq,int id)4012 processFinished(struct module_qstate* qstate, struct iter_qstate* iq,
4013 int id)
4014 {
4015 log_query_info(VERB_QUERY, "finishing processing for",
4016 &qstate->qinfo);
4017
4018 /* store negative cache element for parent side glue. */
4019 if(!qstate->no_cache_store && iq->query_for_pside_glue
4020 && !iq->pside_glue)
4021 iter_store_parentside_neg(qstate->env, &qstate->qinfo,
4022 iq->deleg_msg?iq->deleg_msg->rep:
4023 (iq->response?iq->response->rep:NULL));
4024 if(!iq->response) {
4025 verbose(VERB_ALGO, "No response is set, servfail");
4026 errinf(qstate, "(no response found at query finish)");
4027 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
4028 }
4029
4030 /* Make sure that the RA flag is set (since the presence of
4031 * this module means that recursion is available) */
4032 iq->response->rep->flags |= BIT_RA;
4033
4034 /* Clear the AA flag */
4035 /* FIXME: does this action go here or in some other module? */
4036 iq->response->rep->flags &= ~BIT_AA;
4037
4038 /* make sure QR flag is on */
4039 iq->response->rep->flags |= BIT_QR;
4040
4041 /* explicitly set the EDE string to NULL */
4042 iq->response->rep->reason_bogus_str = NULL;
4043 if((qstate->env->cfg->val_log_level >= 2 ||
4044 qstate->env->cfg->log_servfail) && qstate->errinf &&
4045 !qstate->env->cfg->val_log_squelch) {
4046 char* err_str = errinf_to_str_misc(qstate);
4047 if(err_str) {
4048 verbose(VERB_ALGO, "iterator EDE: %s", err_str);
4049 iq->response->rep->reason_bogus_str = err_str;
4050 }
4051 }
4052
4053 /* we have finished processing this query */
4054 qstate->ext_state[id] = module_finished;
4055
4056 /* TODO: we are using a private TTL, trim the response. */
4057 /* if (mPrivateTTL > 0){IterUtils.setPrivateTTL(resp, mPrivateTTL); } */
4058
4059 /* prepend any items we have accumulated */
4060 if(iq->an_prepend_list || iq->ns_prepend_list) {
4061 if(!iter_prepend(iq, iq->response, qstate->region)) {
4062 log_err("prepend rrsets: out of memory");
4063 return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
4064 }
4065 /* reset the query name back */
4066 iq->response->qinfo = qstate->qinfo;
4067 /* the security state depends on the combination */
4068 iq->response->rep->security = sec_status_unchecked;
4069 /* store message with the finished prepended items,
4070 * but only if we did recursion. The nonrecursion referral
4071 * from cache does not need to be stored in the msg cache. */
4072 if(!qstate->no_cache_store && qstate->query_flags&BIT_RD) {
4073 iter_dns_store(qstate->env, &qstate->qinfo,
4074 iq->response->rep, 0, qstate->prefetch_leeway,
4075 iq->dp&&iq->dp->has_parent_side_NS,
4076 qstate->region, qstate->query_flags,
4077 qstate->qstarttime);
4078 }
4079 }
4080 qstate->return_rcode = LDNS_RCODE_NOERROR;
4081 qstate->return_msg = iq->response;
4082 return 0;
4083 }
4084
4085 /*
4086 * Return priming query results to interested super querystates.
4087 *
4088 * Sets the delegation point and delegation message (not nonRD queries).
4089 * This is a callback from walk_supers.
4090 *
4091 * @param qstate: query state that finished.
4092 * @param id: module id.
4093 * @param super: the qstate to inform.
4094 */
4095 void
iter_inform_super(struct module_qstate * qstate,int id,struct module_qstate * super)4096 iter_inform_super(struct module_qstate* qstate, int id,
4097 struct module_qstate* super)
4098 {
4099 if(!qstate->is_priming && super->qinfo.qclass == LDNS_RR_CLASS_ANY)
4100 processClassResponse(qstate, id, super);
4101 else if(super->qinfo.qtype == LDNS_RR_TYPE_DS && ((struct iter_qstate*)
4102 super->minfo[id])->state == DSNS_FIND_STATE)
4103 processDSNSResponse(qstate, id, super);
4104 else if(qstate->return_rcode != LDNS_RCODE_NOERROR)
4105 error_supers(qstate, id, super);
4106 else if(qstate->is_priming)
4107 prime_supers(qstate, id, super);
4108 else processTargetResponse(qstate, id, super);
4109 }
4110
4111 /**
4112 * Handle iterator state.
4113 * Handle events. This is the real processing loop for events, responsible
4114 * for moving events through the various states. If a processing method
4115 * returns true, then it will be advanced to the next state. If false, then
4116 * processing will stop.
4117 *
4118 * @param qstate: query state.
4119 * @param ie: iterator shared global environment.
4120 * @param iq: iterator query state.
4121 * @param id: module id.
4122 */
4123 static void
iter_handle(struct module_qstate * qstate,struct iter_qstate * iq,struct iter_env * ie,int id)4124 iter_handle(struct module_qstate* qstate, struct iter_qstate* iq,
4125 struct iter_env* ie, int id)
4126 {
4127 int cont = 1;
4128 while(cont) {
4129 verbose(VERB_ALGO, "iter_handle processing q with state %s",
4130 iter_state_to_string(iq->state));
4131 switch(iq->state) {
4132 case INIT_REQUEST_STATE:
4133 cont = processInitRequest(qstate, iq, ie, id);
4134 break;
4135 case INIT_REQUEST_2_STATE:
4136 cont = processInitRequest2(qstate, iq, id);
4137 break;
4138 case INIT_REQUEST_3_STATE:
4139 cont = processInitRequest3(qstate, iq, id);
4140 break;
4141 case QUERYTARGETS_STATE:
4142 cont = processQueryTargets(qstate, iq, ie, id);
4143 break;
4144 case QUERY_RESP_STATE:
4145 cont = processQueryResponse(qstate, iq, ie, id);
4146 break;
4147 case PRIME_RESP_STATE:
4148 cont = processPrimeResponse(qstate, id);
4149 break;
4150 case COLLECT_CLASS_STATE:
4151 cont = processCollectClass(qstate, id);
4152 break;
4153 case DSNS_FIND_STATE:
4154 cont = processDSNSFind(qstate, iq, id);
4155 break;
4156 case FINISHED_STATE:
4157 cont = processFinished(qstate, iq, id);
4158 break;
4159 default:
4160 log_warn("iterator: invalid state: %d",
4161 iq->state);
4162 cont = 0;
4163 break;
4164 }
4165 }
4166 }
4167
4168 /**
4169 * This is the primary entry point for processing request events. Note that
4170 * this method should only be used by external modules.
4171 * @param qstate: query state.
4172 * @param ie: iterator shared global environment.
4173 * @param iq: iterator query state.
4174 * @param id: module id.
4175 */
4176 static void
process_request(struct module_qstate * qstate,struct iter_qstate * iq,struct iter_env * ie,int id)4177 process_request(struct module_qstate* qstate, struct iter_qstate* iq,
4178 struct iter_env* ie, int id)
4179 {
4180 /* external requests start in the INIT state, and finish using the
4181 * FINISHED state. */
4182 iq->state = INIT_REQUEST_STATE;
4183 iq->final_state = FINISHED_STATE;
4184 verbose(VERB_ALGO, "process_request: new external request event");
4185 iter_handle(qstate, iq, ie, id);
4186 }
4187
4188 /** process authoritative server reply */
4189 static void
process_response(struct module_qstate * qstate,struct iter_qstate * iq,struct iter_env * ie,int id,struct outbound_entry * outbound,enum module_ev event)4190 process_response(struct module_qstate* qstate, struct iter_qstate* iq,
4191 struct iter_env* ie, int id, struct outbound_entry* outbound,
4192 enum module_ev event)
4193 {
4194 struct msg_parse* prs;
4195 struct edns_data edns;
4196 sldns_buffer* pkt;
4197
4198 verbose(VERB_ALGO, "process_response: new external response event");
4199 iq->response = NULL;
4200 iq->state = QUERY_RESP_STATE;
4201 if(event == module_event_noreply || event == module_event_error) {
4202 if(event == module_event_noreply && iq->timeout_count >= 3 &&
4203 qstate->env->cfg->use_caps_bits_for_id &&
4204 !iq->caps_fallback && !is_caps_whitelisted(ie, iq)) {
4205 /* start fallback */
4206 iq->caps_fallback = 1;
4207 iq->caps_server = 0;
4208 iq->caps_reply = NULL;
4209 iq->caps_response = NULL;
4210 iq->caps_minimisation_state = DONOT_MINIMISE_STATE;
4211 iq->state = QUERYTARGETS_STATE;
4212 iq->num_current_queries--;
4213 /* need fresh attempts for the 0x20 fallback, if
4214 * that was the cause for the failure */
4215 iter_dec_attempts(iq->dp, 3, ie->outbound_msg_retry);
4216 verbose(VERB_DETAIL, "Capsforid: timeouts, starting fallback");
4217 goto handle_it;
4218 }
4219 goto handle_it;
4220 }
4221 if( (event != module_event_reply && event != module_event_capsfail)
4222 || !qstate->reply) {
4223 log_err("Bad event combined with response");
4224 outbound_list_remove(&iq->outlist, outbound);
4225 errinf(qstate, "module iterator received wrong internal event with a response message");
4226 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
4227 return;
4228 }
4229
4230 /* parse message */
4231 fill_fail_addr(iq, &qstate->reply->remote_addr,
4232 qstate->reply->remote_addrlen);
4233 prs = (struct msg_parse*)regional_alloc(qstate->env->scratch,
4234 sizeof(struct msg_parse));
4235 if(!prs) {
4236 log_err("out of memory on incoming message");
4237 /* like packet got dropped */
4238 goto handle_it;
4239 }
4240 memset(prs, 0, sizeof(*prs));
4241 memset(&edns, 0, sizeof(edns));
4242 pkt = qstate->reply->c->buffer;
4243 sldns_buffer_set_position(pkt, 0);
4244 if(parse_packet(pkt, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) {
4245 verbose(VERB_ALGO, "parse error on reply packet");
4246 iq->parse_failures++;
4247 goto handle_it;
4248 }
4249 /* edns is not examined, but removed from message to help cache */
4250 if(parse_extract_edns_from_response_msg(prs, &edns, qstate->env->scratch) !=
4251 LDNS_RCODE_NOERROR) {
4252 iq->parse_failures++;
4253 goto handle_it;
4254 }
4255
4256 /* Copy the edns options we may got from the back end */
4257 if(edns.opt_list_in) {
4258 qstate->edns_opts_back_in = edns_opt_copy_region(edns.opt_list_in,
4259 qstate->region);
4260 if(!qstate->edns_opts_back_in) {
4261 log_err("out of memory on incoming message");
4262 /* like packet got dropped */
4263 goto handle_it;
4264 }
4265 }
4266 if(!inplace_cb_edns_back_parsed_call(qstate->env, qstate)) {
4267 log_err("unable to call edns_back_parsed callback");
4268 goto handle_it;
4269 }
4270
4271 /* remove CD-bit, we asked for in case we handle validation ourself */
4272 prs->flags &= ~BIT_CD;
4273
4274 /* normalize and sanitize: easy to delete items from linked lists */
4275 if(!scrub_message(pkt, prs, &iq->qinfo_out, iq->dp->name,
4276 qstate->env->scratch, qstate->env, qstate, ie)) {
4277 /* if 0x20 enabled, start fallback, but we have no message */
4278 if(event == module_event_capsfail && !iq->caps_fallback) {
4279 iq->caps_fallback = 1;
4280 iq->caps_server = 0;
4281 iq->caps_reply = NULL;
4282 iq->caps_response = NULL;
4283 iq->caps_minimisation_state = DONOT_MINIMISE_STATE;
4284 iq->state = QUERYTARGETS_STATE;
4285 iq->num_current_queries--;
4286 verbose(VERB_DETAIL, "Capsforid: scrub failed, starting fallback with no response");
4287 }
4288 iq->scrub_failures++;
4289 goto handle_it;
4290 }
4291
4292 /* allocate response dns_msg in region */
4293 iq->response = dns_alloc_msg(pkt, prs, qstate->region);
4294 if(!iq->response)
4295 goto handle_it;
4296 log_query_info(VERB_DETAIL, "response for", &qstate->qinfo);
4297 log_name_addr(VERB_DETAIL, "reply from", iq->dp->name,
4298 &qstate->reply->remote_addr, qstate->reply->remote_addrlen);
4299 if(verbosity >= VERB_ALGO)
4300 log_dns_msg("incoming scrubbed packet:", &iq->response->qinfo,
4301 iq->response->rep);
4302
4303 if(event == module_event_capsfail || iq->caps_fallback) {
4304 if(qstate->env->cfg->qname_minimisation &&
4305 iq->minimisation_state != DONOT_MINIMISE_STATE) {
4306 /* Skip QNAME minimisation for next query, since that
4307 * one has to match the current query. */
4308 iq->minimisation_state = SKIP_MINIMISE_STATE;
4309 }
4310 /* for fallback we care about main answer, not additionals */
4311 /* removing that makes comparison more likely to succeed */
4312 caps_strip_reply(iq->response->rep);
4313
4314 if(iq->caps_fallback &&
4315 iq->caps_minimisation_state != iq->minimisation_state) {
4316 /* QNAME minimisation state has changed, restart caps
4317 * fallback. */
4318 iq->caps_fallback = 0;
4319 }
4320
4321 if(!iq->caps_fallback) {
4322 /* start fallback */
4323 iq->caps_fallback = 1;
4324 iq->caps_server = 0;
4325 iq->caps_reply = iq->response->rep;
4326 iq->caps_response = iq->response;
4327 iq->caps_minimisation_state = iq->minimisation_state;
4328 iq->state = QUERYTARGETS_STATE;
4329 iq->num_current_queries--;
4330 verbose(VERB_DETAIL, "Capsforid: starting fallback");
4331 goto handle_it;
4332 } else {
4333 /* check if reply is the same, otherwise, fail */
4334 if(!iq->caps_reply) {
4335 iq->caps_reply = iq->response->rep;
4336 iq->caps_response = iq->response;
4337 iq->caps_server = -1; /*become zero at ++,
4338 so that we start the full set of trials */
4339 } else if(caps_failed_rcode(iq->caps_reply) &&
4340 !caps_failed_rcode(iq->response->rep)) {
4341 /* prefer to upgrade to non-SERVFAIL */
4342 iq->caps_reply = iq->response->rep;
4343 iq->caps_response = iq->response;
4344 } else if(!caps_failed_rcode(iq->caps_reply) &&
4345 caps_failed_rcode(iq->response->rep)) {
4346 /* if we have non-SERVFAIL as answer then
4347 * we can ignore SERVFAILs for the equality
4348 * comparison */
4349 /* no instructions here, skip other else */
4350 } else if(caps_failed_rcode(iq->caps_reply) &&
4351 caps_failed_rcode(iq->response->rep)) {
4352 /* failure is same as other failure in fallbk*/
4353 /* no instructions here, skip other else */
4354 } else if(!reply_equal(iq->response->rep, iq->caps_reply,
4355 qstate->env->scratch)) {
4356 verbose(VERB_DETAIL, "Capsforid fallback: "
4357 "getting different replies, failed");
4358 outbound_list_remove(&iq->outlist, outbound);
4359 errinf(qstate, "0x20 failed, then got different replies in fallback");
4360 (void)error_response(qstate, id,
4361 LDNS_RCODE_SERVFAIL);
4362 return;
4363 }
4364 /* continue the fallback procedure at next server */
4365 iq->caps_server++;
4366 iq->state = QUERYTARGETS_STATE;
4367 iq->num_current_queries--;
4368 verbose(VERB_DETAIL, "Capsforid: reply is equal. "
4369 "go to next fallback");
4370 goto handle_it;
4371 }
4372 }
4373 iq->caps_fallback = 0; /* if we were in fallback, 0x20 is OK now */
4374
4375 handle_it:
4376 outbound_list_remove(&iq->outlist, outbound);
4377 iter_handle(qstate, iq, ie, id);
4378 }
4379
4380 void
iter_operate(struct module_qstate * qstate,enum module_ev event,int id,struct outbound_entry * outbound)4381 iter_operate(struct module_qstate* qstate, enum module_ev event, int id,
4382 struct outbound_entry* outbound)
4383 {
4384 struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id];
4385 struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];
4386 verbose(VERB_QUERY, "iterator[module %d] operate: extstate:%s event:%s",
4387 id, strextstate(qstate->ext_state[id]), strmodulevent(event));
4388 if(iq) log_query_info(VERB_QUERY, "iterator operate: query",
4389 &qstate->qinfo);
4390 if(iq && qstate->qinfo.qname != iq->qchase.qname)
4391 log_query_info(VERB_QUERY, "iterator operate: chased to",
4392 &iq->qchase);
4393
4394 /* perform iterator state machine */
4395 if((event == module_event_new || event == module_event_pass) &&
4396 iq == NULL) {
4397 if(!iter_new(qstate, id)) {
4398 errinf(qstate, "malloc failure, new iterator module allocation");
4399 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
4400 return;
4401 }
4402 iq = (struct iter_qstate*)qstate->minfo[id];
4403 process_request(qstate, iq, ie, id);
4404 return;
4405 }
4406 if(iq && event == module_event_pass) {
4407 iter_handle(qstate, iq, ie, id);
4408 return;
4409 }
4410 if(iq && outbound) {
4411 process_response(qstate, iq, ie, id, outbound, event);
4412 return;
4413 }
4414 if(event == module_event_error) {
4415 verbose(VERB_ALGO, "got called with event error, giving up");
4416 errinf(qstate, "iterator module got the error event");
4417 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
4418 return;
4419 }
4420
4421 log_err("bad event for iterator");
4422 errinf(qstate, "iterator module received wrong event");
4423 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
4424 }
4425
4426 void
iter_clear(struct module_qstate * qstate,int id)4427 iter_clear(struct module_qstate* qstate, int id)
4428 {
4429 struct iter_qstate* iq;
4430 if(!qstate)
4431 return;
4432 iq = (struct iter_qstate*)qstate->minfo[id];
4433 if(iq) {
4434 outbound_list_clear(&iq->outlist);
4435 if(iq->target_count && --iq->target_count[TARGET_COUNT_REF] == 0) {
4436 free(iq->target_count);
4437 if(*iq->nxns_dp) free(*iq->nxns_dp);
4438 free(iq->nxns_dp);
4439 }
4440 iq->num_current_queries = 0;
4441 }
4442 qstate->minfo[id] = NULL;
4443 }
4444
4445 size_t
iter_get_mem(struct module_env * env,int id)4446 iter_get_mem(struct module_env* env, int id)
4447 {
4448 struct iter_env* ie = (struct iter_env*)env->modinfo[id];
4449 if(!ie)
4450 return 0;
4451 return sizeof(*ie) + sizeof(int)*((size_t)ie->max_dependency_depth+1)
4452 + donotq_get_mem(ie->donotq) + priv_get_mem(ie->priv);
4453 }
4454
4455 /**
4456 * The iterator function block
4457 */
4458 static struct module_func_block iter_block = {
4459 "iterator",
4460 &iter_init, &iter_deinit, &iter_operate, &iter_inform_super,
4461 &iter_clear, &iter_get_mem
4462 };
4463
4464 struct module_func_block*
iter_get_funcblock(void)4465 iter_get_funcblock(void)
4466 {
4467 return &iter_block;
4468 }
4469
4470 const char*
iter_state_to_string(enum iter_state state)4471 iter_state_to_string(enum iter_state state)
4472 {
4473 switch (state)
4474 {
4475 case INIT_REQUEST_STATE :
4476 return "INIT REQUEST STATE";
4477 case INIT_REQUEST_2_STATE :
4478 return "INIT REQUEST STATE (stage 2)";
4479 case INIT_REQUEST_3_STATE:
4480 return "INIT REQUEST STATE (stage 3)";
4481 case QUERYTARGETS_STATE :
4482 return "QUERY TARGETS STATE";
4483 case PRIME_RESP_STATE :
4484 return "PRIME RESPONSE STATE";
4485 case COLLECT_CLASS_STATE :
4486 return "COLLECT CLASS STATE";
4487 case DSNS_FIND_STATE :
4488 return "DSNS FIND STATE";
4489 case QUERY_RESP_STATE :
4490 return "QUERY RESPONSE STATE";
4491 case FINISHED_STATE :
4492 return "FINISHED RESPONSE STATE";
4493 default :
4494 return "UNKNOWN ITER STATE";
4495 }
4496 }
4497
4498 int
iter_state_is_responsestate(enum iter_state s)4499 iter_state_is_responsestate(enum iter_state s)
4500 {
4501 switch(s) {
4502 case INIT_REQUEST_STATE :
4503 case INIT_REQUEST_2_STATE :
4504 case INIT_REQUEST_3_STATE :
4505 case QUERYTARGETS_STATE :
4506 case COLLECT_CLASS_STATE :
4507 return 0;
4508 default:
4509 break;
4510 }
4511 return 1;
4512 }
4513