contrib/unbound/services/cache/dns.c

   1 /*
   2  * services/cache/dns.c - Cache services for DNS using msg and rrset caches.
   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 the DNS cache.
  40  */
  41 #include "config.h"
  42 #include "iterator/iter_delegpt.h"
  43 #include "validator/val_nsec.h"
  44 #include "services/cache/dns.h"
  45 #include "services/cache/rrset.h"
  46 #include "util/data/msgreply.h"
  47 #include "util/data/packed_rrset.h"
  48 #include "util/data/dname.h"
  49 #include "util/module.h"
  50 #include "util/net_help.h"
  51 #include "util/regional.h"
  52 #include "util/config_file.h"
  53 #include "sldns/sbuffer.h"
  54
  55 /** store rrsets in the rrset cache.
  56  * @param env: module environment with caches.
  57  * @param rep: contains list of rrsets to store.
  58  * @param now: current time.
  59  * @param leeway: during prefetch how much leeway to update TTLs.
  60  *      This makes rrsets (other than type NS) timeout sooner so they get
  61  *      updated with a new full TTL.
  62  *      Type NS does not get this, because it must not be refreshed from the
  63  *      child domain, but keep counting down properly.
  64  * @param pside: if from parentside discovered NS, so that its NS is okay
  65  *      in a prefetch situation to be updated (without becoming sticky).
  66  * @param qrep: update rrsets here if cache is better
  67  * @param region: for qrep allocs.
  68  */
  69 static void
  70 store_rrsets(struct module_env* env, struct reply_info* rep, time_t now,
  71         time_t leeway, int pside, struct reply_info* qrep,
  72         struct regional* region)
  73 {
  74         size_t i;
  75         /* see if rrset already exists in cache, if not insert it. */
  76         for(i=0; i<rep->rrset_count; i++) {
  77                 rep->ref[i].key = rep->rrsets[i];
  78                 rep->ref[i].id = rep->rrsets[i]->id;
  79                 /* update ref if it was in the cache */
  80                 switch(rrset_cache_update(env->rrset_cache, &rep->ref[i],
  81                         env->alloc, now + ((ntohs(rep->ref[i].key->rk.type)==
  82                         LDNS_RR_TYPE_NS && !pside)?0:leeway))) {
  83                 case 0: /* ref unchanged, item inserted */
  84                         break;
  85                 case 2: /* ref updated, cache is superior */
  86                         if(region) {
  87                                 struct ub_packed_rrset_key* ck;
  88                                 lock_rw_rdlock(&rep->ref[i].key->entry.lock);
  89                                 /* if deleted rrset, do not copy it */
  90                                 if(rep->ref[i].key->id == 0)
  91                                         ck = NULL;
  92                                 else    ck = packed_rrset_copy_region(
  93                                         rep->ref[i].key, region, now);
  94                                 lock_rw_unlock(&rep->ref[i].key->entry.lock);
  95                                 if(ck) {
  96                                         /* use cached copy if memory allows */
  97                                         qrep->rrsets[i] = ck;
  98                                 }
  99                         }
 100                         /* no break: also copy key item */
 101                 case 1: /* ref updated, item inserted */
 102                         rep->rrsets[i] = rep->ref[i].key;
 103                 }
 104         }
 105 }
 106
 107 void
 108 dns_cache_store_msg(struct module_env* env, struct query_info* qinfo,
 109         hashvalue_type hash, struct reply_info* rep, time_t leeway, int pside,
 110         struct reply_info* qrep, struct regional* region)
 111 {
 112         struct msgreply_entry* e;
 113         time_t ttl = rep->ttl;
 114         size_t i;
 115
 116         /* store RRsets */
 117         for(i=0; i<rep->rrset_count; i++) {
 118                 rep->ref[i].key = rep->rrsets[i];
 119                 rep->ref[i].id = rep->rrsets[i]->id;
 120         }
 121
 122         /* there was a reply_info_sortref(rep) here but it seems to be
 123          * unnecessary, because the cache gets locked per rrset. */
 124         reply_info_set_ttls(rep, *env->now);
 125         store_rrsets(env, rep, *env->now, leeway, pside, qrep, region);
 126         if(ttl == 0) {
 127                 /* we do not store the message, but we did store the RRs,
 128                  * which could be useful for delegation information */
 129                 verbose(VERB_ALGO, "TTL 0: dropped msg from cache");
 130                 free(rep);
 131                 return;
 132         }
 133
 134         /* store msg in the cache */
 135         reply_info_sortref(rep);
 136         if(!(e = query_info_entrysetup(qinfo, rep, hash))) {
 137                 log_err("store_msg: malloc failed");
 138                 return;
 139         }
 140         slabhash_insert(env->msg_cache, hash, &e->entry, rep, env->alloc);
 141 }
 142
 143 /** find closest NS or DNAME and returns the rrset (locked) */
 144 static struct ub_packed_rrset_key*
 145 find_closest_of_type(struct module_env* env, uint8_t* qname, size_t qnamelen,
 146         uint16_t qclass, time_t now, uint16_t searchtype, int stripfront)
 147 {
 148         struct ub_packed_rrset_key *rrset;
 149         uint8_t lablen;
 150
 151         if(stripfront) {
 152                 /* strip off so that DNAMEs have strict subdomain match */
 153                 lablen = *qname;
 154                 qname += lablen + 1;
 155                 qnamelen -= lablen + 1;
 156         }
 157
 158         /* snip off front part of qname until the type is found */
 159         while(qnamelen > 0) {
 160                 if((rrset = rrset_cache_lookup(env->rrset_cache, qname,
 161                         qnamelen, searchtype, qclass, 0, now, 0)))
 162                         return rrset;
 163
 164                 /* snip off front label */
 165                 lablen = *qname;
 166                 qname += lablen + 1;
 167                 qnamelen -= lablen + 1;
 168         }
 169         return NULL;
 170 }
 171
 172 /** add addr to additional section */
 173 static void
 174 addr_to_additional(struct ub_packed_rrset_key* rrset, struct regional* region,
 175         struct dns_msg* msg, time_t now)
 176 {
 177         if((msg->rep->rrsets[msg->rep->rrset_count] =
 178                 packed_rrset_copy_region(rrset, region, now))) {
 179                 msg->rep->ar_numrrsets++;
 180                 msg->rep->rrset_count++;
 181         }
 182 }
 183
 184 /** lookup message in message cache */
 185 static struct msgreply_entry*
 186 msg_cache_lookup(struct module_env* env, uint8_t* qname, size_t qnamelen,
 187         uint16_t qtype, uint16_t qclass, uint16_t flags, time_t now, int wr)
 188 {
 189         struct lruhash_entry* e;
 190         struct query_info k;
 191         hashvalue_type h;
 192
 193         k.qname = qname;
 194         k.qname_len = qnamelen;
 195         k.qtype = qtype;
 196         k.qclass = qclass;
 197         k.local_alias = NULL;
 198         h = query_info_hash(&k, flags);
 199         e = slabhash_lookup(env->msg_cache, h, &k, wr);
 200
 201         if(!e) return NULL;
 202         if( now > ((struct reply_info*)e->data)->ttl ) {
 203                 lock_rw_unlock(&e->lock);
 204                 return NULL;
 205         }
 206         return (struct msgreply_entry*)e->key;
 207 }
 208
 209 /** find and add A and AAAA records for nameservers in delegpt */
 210 static int
 211 find_add_addrs(struct module_env* env, uint16_t qclass,
 212         struct regional* region, struct delegpt* dp, time_t now,
 213         struct dns_msg** msg)
 214 {
 215         struct delegpt_ns* ns;
 216         struct msgreply_entry* neg;
 217         struct ub_packed_rrset_key* akey;
 218         for(ns = dp->nslist; ns; ns = ns->next) {
 219                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 220                         ns->namelen, LDNS_RR_TYPE_A, qclass, 0, now, 0);
 221                 if(akey) {
 222                         if(!delegpt_add_rrset_A(dp, region, akey, 0)) {
 223                                 lock_rw_unlock(&akey->entry.lock);
 224                                 return 0;
 225                         }
 226                         if(msg)
 227                                 addr_to_additional(akey, region, *msg, now);
 228                         lock_rw_unlock(&akey->entry.lock);
 229                 } else {
 230                         /* BIT_CD on false because delegpt lookup does
 231                          * not use dns64 translation */
 232                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 233                                 LDNS_RR_TYPE_A, qclass, 0, now, 0);
 234                         if(neg) {
 235                                 delegpt_add_neg_msg(dp, neg);
 236                                 lock_rw_unlock(&neg->entry.lock);
 237                         }
 238                 }
 239                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 240                         ns->namelen, LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
 241                 if(akey) {
 242                         if(!delegpt_add_rrset_AAAA(dp, region, akey, 0)) {
 243                                 lock_rw_unlock(&akey->entry.lock);
 244                                 return 0;
 245                         }
 246                         if(msg)
 247                                 addr_to_additional(akey, region, *msg, now);
 248                         lock_rw_unlock(&akey->entry.lock);
 249                 } else {
 250                         /* BIT_CD on false because delegpt lookup does
 251                          * not use dns64 translation */
 252                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 253                                 LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
 254                         if(neg) {
 255                                 delegpt_add_neg_msg(dp, neg);
 256                                 lock_rw_unlock(&neg->entry.lock);
 257                         }
 258                 }
 259         }
 260         return 1;
 261 }
 262
 263 /** find and add A and AAAA records for missing nameservers in delegpt */
 264 int
 265 cache_fill_missing(struct module_env* env, uint16_t qclass,
 266         struct regional* region, struct delegpt* dp)
 267 {
 268         struct delegpt_ns* ns;
 269         struct msgreply_entry* neg;
 270         struct ub_packed_rrset_key* akey;
 271         time_t now = *env->now;
 272         for(ns = dp->nslist; ns; ns = ns->next) {
 273                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 274                         ns->namelen, LDNS_RR_TYPE_A, qclass, 0, now, 0);
 275                 if(akey) {
 276                         if(!delegpt_add_rrset_A(dp, region, akey, ns->lame)) {
 277                                 lock_rw_unlock(&akey->entry.lock);
 278                                 return 0;
 279                         }
 280                         log_nametypeclass(VERB_ALGO, "found in cache",
 281                                 ns->name, LDNS_RR_TYPE_A, qclass);
 282                         lock_rw_unlock(&akey->entry.lock);
 283                 } else {
 284                         /* BIT_CD on false because delegpt lookup does
 285                          * not use dns64 translation */
 286                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 287                                 LDNS_RR_TYPE_A, qclass, 0, now, 0);
 288                         if(neg) {
 289                                 delegpt_add_neg_msg(dp, neg);
 290                                 lock_rw_unlock(&neg->entry.lock);
 291                         }
 292                 }
 293                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 294                         ns->namelen, LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
 295                 if(akey) {
 296                         if(!delegpt_add_rrset_AAAA(dp, region, akey, ns->lame)) {
 297                                 lock_rw_unlock(&akey->entry.lock);
 298                                 return 0;
 299                         }
 300                         log_nametypeclass(VERB_ALGO, "found in cache",
 301                                 ns->name, LDNS_RR_TYPE_AAAA, qclass);
 302                         lock_rw_unlock(&akey->entry.lock);
 303                 } else {
 304                         /* BIT_CD on false because delegpt lookup does
 305                          * not use dns64 translation */
 306                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 307                                 LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
 308                         if(neg) {
 309                                 delegpt_add_neg_msg(dp, neg);
 310                                 lock_rw_unlock(&neg->entry.lock);
 311                         }
 312                 }
 313         }
 314         return 1;
 315 }
 316
 317 /** find and add DS or NSEC to delegation msg */
 318 static void
 319 find_add_ds(struct module_env* env, struct regional* region,
 320         struct dns_msg* msg, struct delegpt* dp, time_t now)
 321 {
 322         /* Lookup the DS or NSEC at the delegation point. */
 323         struct ub_packed_rrset_key* rrset = rrset_cache_lookup(
 324                 env->rrset_cache, dp->name, dp->namelen, LDNS_RR_TYPE_DS,
 325                 msg->qinfo.qclass, 0, now, 0);
 326         if(!rrset) {
 327                 /* NOTE: this won't work for alternate NSEC schemes
 328                  *      (opt-in, NSEC3) */
 329                 rrset = rrset_cache_lookup(env->rrset_cache, dp->name,
 330                         dp->namelen, LDNS_RR_TYPE_NSEC, msg->qinfo.qclass,
 331                         0, now, 0);
 332                 /* Note: the PACKED_RRSET_NSEC_AT_APEX flag is not used.
 333                  * since this is a referral, we need the NSEC at the parent
 334                  * side of the zone cut, not the NSEC at apex side. */
 335                 if(rrset && nsec_has_type(rrset, LDNS_RR_TYPE_DS)) {
 336                         lock_rw_unlock(&rrset->entry.lock);
 337                         rrset = NULL; /* discard wrong NSEC */
 338                 }
 339         }
 340         if(rrset) {
 341                 /* add it to auth section. This is the second rrset. */
 342                 if((msg->rep->rrsets[msg->rep->rrset_count] =
 343                         packed_rrset_copy_region(rrset, region, now))) {
 344                         msg->rep->ns_numrrsets++;
 345                         msg->rep->rrset_count++;
 346                 }
 347                 lock_rw_unlock(&rrset->entry.lock);
 348         }
 349 }
 350
 351 struct dns_msg*
 352 dns_msg_create(uint8_t* qname, size_t qnamelen, uint16_t qtype,
 353         uint16_t qclass, struct regional* region, size_t capacity)
 354 {
 355         struct dns_msg* msg = (struct dns_msg*)regional_alloc(region,
 356                 sizeof(struct dns_msg));
 357         if(!msg)
 358                 return NULL;
 359         msg->qinfo.qname = regional_alloc_init(region, qname, qnamelen);
 360         if(!msg->qinfo.qname)
 361                 return NULL;
 362         msg->qinfo.qname_len = qnamelen;
 363         msg->qinfo.qtype = qtype;
 364         msg->qinfo.qclass = qclass;
 365         msg->qinfo.local_alias = NULL;
 366         /* non-packed reply_info, because it needs to grow the array */
 367         msg->rep = (struct reply_info*)regional_alloc_zero(region,
 368                 sizeof(struct reply_info)-sizeof(struct rrset_ref));
 369         if(!msg->rep)
 370                 return NULL;
 371         if(capacity > RR_COUNT_MAX)
 372                 return NULL; /* integer overflow protection */
 373         msg->rep->flags = BIT_QR; /* with QR, no AA */
 374         msg->rep->qdcount = 1;
 375         msg->rep->rrsets = (struct ub_packed_rrset_key**)
 376                 regional_alloc(region,
 377                 capacity*sizeof(struct ub_packed_rrset_key*));
 378         if(!msg->rep->rrsets)
 379                 return NULL;
 380         return msg;
 381 }
 382
 383 int
 384 dns_msg_authadd(struct dns_msg* msg, struct regional* region,
 385         struct ub_packed_rrset_key* rrset, time_t now)
 386 {
 387         if(!(msg->rep->rrsets[msg->rep->rrset_count++] =
 388                 packed_rrset_copy_region(rrset, region, now)))
 389                 return 0;
 390         msg->rep->ns_numrrsets++;
 391         return 1;
 392 }
 393
 394 /** add rrset to answer section */
 395 static int
 396 dns_msg_ansadd(struct dns_msg* msg, struct regional* region,
 397         struct ub_packed_rrset_key* rrset, time_t now)
 398 {
 399         if(!(msg->rep->rrsets[msg->rep->rrset_count++] =
 400                 packed_rrset_copy_region(rrset, region, now)))
 401                 return 0;
 402         msg->rep->an_numrrsets++;
 403         return 1;
 404 }
 405
 406 struct delegpt*
 407 dns_cache_find_delegation(struct module_env* env, uint8_t* qname,
 408         size_t qnamelen, uint16_t qtype, uint16_t qclass,
 409         struct regional* region, struct dns_msg** msg, time_t now)
 410 {
 411         /* try to find closest NS rrset */
 412         struct ub_packed_rrset_key* nskey;
 413         struct packed_rrset_data* nsdata;
 414         struct delegpt* dp;
 415
 416         nskey = find_closest_of_type(env, qname, qnamelen, qclass, now,
 417                 LDNS_RR_TYPE_NS, 0);
 418         if(!nskey) /* hope the caller has hints to prime or something */
 419                 return NULL;
 420         nsdata = (struct packed_rrset_data*)nskey->entry.data;
 421         /* got the NS key, create delegation point */
 422         dp = delegpt_create(region);
 423         if(!dp || !delegpt_set_name(dp, region, nskey->rk.dname)) {
 424                 lock_rw_unlock(&nskey->entry.lock);
 425                 log_err("find_delegation: out of memory");
 426                 return NULL;
 427         }
 428         /* create referral message */
 429         if(msg) {
 430                 /* allocate the array to as much as we could need:
 431                  *      NS rrset + DS/NSEC rrset +
 432                  *      A rrset for every NS RR
 433                  *      AAAA rrset for every NS RR
 434                  */
 435                 *msg = dns_msg_create(qname, qnamelen, qtype, qclass, region,
 436                         2 + nsdata->count*2);
 437                 if(!*msg || !dns_msg_authadd(*msg, region, nskey, now)) {
 438                         lock_rw_unlock(&nskey->entry.lock);
 439                         log_err("find_delegation: out of memory");
 440                         return NULL;
 441                 }
 442         }
 443         if(!delegpt_rrset_add_ns(dp, region, nskey, 0))
 444                 log_err("find_delegation: addns out of memory");
 445         lock_rw_unlock(&nskey->entry.lock); /* first unlock before next lookup*/
 446         /* find and add DS/NSEC (if any) */
 447         if(msg)
 448                 find_add_ds(env, region, *msg, dp, now);
 449         /* find and add A entries */
 450         if(!find_add_addrs(env, qclass, region, dp, now, msg))
 451                 log_err("find_delegation: addrs out of memory");
 452         return dp;
 453 }
 454
 455 /** allocate dns_msg from query_info and reply_info */
 456 static struct dns_msg*
 457 gen_dns_msg(struct regional* region, struct query_info* q, size_t num)
 458 {
 459         struct dns_msg* msg = (struct dns_msg*)regional_alloc(region,
 460                 sizeof(struct dns_msg));
 461         if(!msg)
 462                 return NULL;
 463         memcpy(&msg->qinfo, q, sizeof(struct query_info));
 464         msg->qinfo.qname = regional_alloc_init(region, q->qname, q->qname_len);
 465         if(!msg->qinfo.qname)
 466                 return NULL;
 467         /* allocate replyinfo struct and rrset key array separately */
 468         msg->rep = (struct reply_info*)regional_alloc(region,
 469                 sizeof(struct reply_info) - sizeof(struct rrset_ref));
 470         if(!msg->rep)
 471                 return NULL;
 472         if(num > RR_COUNT_MAX)
 473                 return NULL; /* integer overflow protection */
 474         msg->rep->rrsets = (struct ub_packed_rrset_key**)
 475                 regional_alloc(region,
 476                 num * sizeof(struct ub_packed_rrset_key*));
 477         if(!msg->rep->rrsets)
 478                 return NULL;
 479         return msg;
 480 }
 481
 482 struct dns_msg*
 483 tomsg(struct module_env* env, struct query_info* q, struct reply_info* r,
 484         struct regional* region, time_t now, struct regional* scratch)
 485 {
 486         struct dns_msg* msg;
 487         size_t i;
 488         if(now > r->ttl)
 489                 return NULL;
 490         msg = gen_dns_msg(region, q, r->rrset_count);
 491         if(!msg)
 492                 return NULL;
 493         msg->rep->flags = r->flags;
 494         msg->rep->qdcount = r->qdcount;
 495         msg->rep->ttl = r->ttl - now;
 496         if(r->prefetch_ttl > now)
 497                 msg->rep->prefetch_ttl = r->prefetch_ttl - now;
 498         else    msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 499         msg->rep->security = r->security;
 500         msg->rep->an_numrrsets = r->an_numrrsets;
 501         msg->rep->ns_numrrsets = r->ns_numrrsets;
 502         msg->rep->ar_numrrsets = r->ar_numrrsets;
 503         msg->rep->rrset_count = r->rrset_count;
 504         msg->rep->authoritative = r->authoritative;
 505         if(!rrset_array_lock(r->ref, r->rrset_count, now))
 506                 return NULL;
 507         if(r->an_numrrsets > 0 && (r->rrsets[0]->rk.type == htons(
 508                 LDNS_RR_TYPE_CNAME) || r->rrsets[0]->rk.type == htons(
 509                 LDNS_RR_TYPE_DNAME)) && !reply_check_cname_chain(q, r)) {
 510                 /* cname chain is now invalid, reconstruct msg */
 511                 rrset_array_unlock(r->ref, r->rrset_count);
 512                 return NULL;
 513         }
 514         if(r->security == sec_status_secure && !reply_all_rrsets_secure(r)) {
 515                 /* message rrsets have changed status, revalidate */
 516                 rrset_array_unlock(r->ref, r->rrset_count);
 517                 return NULL;
 518         }
 519         for(i=0; i<msg->rep->rrset_count; i++) {
 520                 msg->rep->rrsets[i] = packed_rrset_copy_region(r->rrsets[i],
 521                         region, now);
 522                 if(!msg->rep->rrsets[i]) {
 523                         rrset_array_unlock(r->ref, r->rrset_count);
 524                         return NULL;
 525                 }
 526         }
 527         if(env)
 528                 rrset_array_unlock_touch(env->rrset_cache, scratch, r->ref,
 529                 r->rrset_count);
 530         else
 531                 rrset_array_unlock(r->ref, r->rrset_count);
 532         return msg;
 533 }
 534
 535 /** synthesize RRset-only response from cached RRset item */
 536 static struct dns_msg*
 537 rrset_msg(struct ub_packed_rrset_key* rrset, struct regional* region,
 538         time_t now, struct query_info* q)
 539 {
 540         struct dns_msg* msg;
 541         struct packed_rrset_data* d = (struct packed_rrset_data*)
 542                 rrset->entry.data;
 543         if(now > d->ttl)
 544                 return NULL;
 545         msg = gen_dns_msg(region, q, 1); /* only the CNAME (or other) RRset */
 546         if(!msg)
 547                 return NULL;
 548         msg->rep->flags = BIT_QR; /* reply, no AA, no error */
 549         msg->rep->authoritative = 0; /* reply stored in cache can't be authoritative */
 550         msg->rep->qdcount = 1;
 551         msg->rep->ttl = d->ttl - now;
 552         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 553         msg->rep->security = sec_status_unchecked;
 554         msg->rep->an_numrrsets = 1;
 555         msg->rep->ns_numrrsets = 0;
 556         msg->rep->ar_numrrsets = 0;
 557         msg->rep->rrset_count = 1;
 558         msg->rep->rrsets[0] = packed_rrset_copy_region(rrset, region, now);
 559         if(!msg->rep->rrsets[0]) /* copy CNAME */
 560                 return NULL;
 561         return msg;
 562 }
 563
 564 /** synthesize DNAME+CNAME response from cached DNAME item */
 565 static struct dns_msg*
 566 synth_dname_msg(struct ub_packed_rrset_key* rrset, struct regional* region,
 567         time_t now, struct query_info* q)
 568 {
 569         struct dns_msg* msg;
 570         struct ub_packed_rrset_key* ck;
 571         struct packed_rrset_data* newd, *d = (struct packed_rrset_data*)
 572                 rrset->entry.data;
 573         uint8_t* newname, *dtarg = NULL;
 574         size_t newlen, dtarglen;
 575         if(now > d->ttl)
 576                 return NULL;
 577         /* only allow validated (with DNSSEC) DNAMEs used from cache
 578          * for insecure DNAMEs, query again. */
 579         if(d->security != sec_status_secure)
 580                 return NULL;
 581         msg = gen_dns_msg(region, q, 2); /* DNAME + CNAME RRset */
 582         if(!msg)
 583                 return NULL;
 584         msg->rep->flags = BIT_QR; /* reply, no AA, no error */
 585         msg->rep->authoritative = 0; /* reply stored in cache can't be authoritative */
 586         msg->rep->qdcount = 1;
 587         msg->rep->ttl = d->ttl - now;
 588         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 589         msg->rep->security = sec_status_unchecked;
 590         msg->rep->an_numrrsets = 1;
 591         msg->rep->ns_numrrsets = 0;
 592         msg->rep->ar_numrrsets = 0;
 593         msg->rep->rrset_count = 1;
 594         msg->rep->rrsets[0] = packed_rrset_copy_region(rrset, region, now);
 595         if(!msg->rep->rrsets[0]) /* copy DNAME */
 596                 return NULL;
 597         /* synth CNAME rrset */
 598         get_cname_target(rrset, &dtarg, &dtarglen);
 599         if(!dtarg)
 600                 return NULL;
 601         newlen = q->qname_len + dtarglen - rrset->rk.dname_len;
 602         if(newlen > LDNS_MAX_DOMAINLEN) {
 603                 msg->rep->flags |= LDNS_RCODE_YXDOMAIN;
 604                 return msg;
 605         }
 606         newname = (uint8_t*)regional_alloc(region, newlen);
 607         if(!newname)
 608                 return NULL;
 609         /* new name is concatenation of qname front (without DNAME owner)
 610          * and DNAME target name */
 611         memcpy(newname, q->qname, q->qname_len-rrset->rk.dname_len);
 612         memmove(newname+(q->qname_len-rrset->rk.dname_len), dtarg, dtarglen);
 613         /* create rest of CNAME rrset */
 614         ck = (struct ub_packed_rrset_key*)regional_alloc(region,
 615                 sizeof(struct ub_packed_rrset_key));
 616         if(!ck)
 617                 return NULL;
 618         memset(&ck->entry, 0, sizeof(ck->entry));
 619         msg->rep->rrsets[1] = ck;
 620         ck->entry.key = ck;
 621         ck->rk.type = htons(LDNS_RR_TYPE_CNAME);
 622         ck->rk.rrset_class = rrset->rk.rrset_class;
 623         ck->rk.flags = 0;
 624         ck->rk.dname = regional_alloc_init(region, q->qname, q->qname_len);
 625         if(!ck->rk.dname)
 626                 return NULL;
 627         ck->rk.dname_len = q->qname_len;
 628         ck->entry.hash = rrset_key_hash(&ck->rk);
 629         newd = (struct packed_rrset_data*)regional_alloc_zero(region,
 630                 sizeof(struct packed_rrset_data) + sizeof(size_t) +
 631                 sizeof(uint8_t*) + sizeof(time_t) + sizeof(uint16_t)
 632                 + newlen);
 633         if(!newd)
 634                 return NULL;
 635         ck->entry.data = newd;
 636         newd->ttl = 0; /* 0 for synthesized CNAME TTL */
 637         newd->count = 1;
 638         newd->rrsig_count = 0;
 639         newd->trust = rrset_trust_ans_noAA;
 640         newd->rr_len = (size_t*)((uint8_t*)newd +
 641                 sizeof(struct packed_rrset_data));
 642         newd->rr_len[0] = newlen + sizeof(uint16_t);
 643         packed_rrset_ptr_fixup(newd);
 644         newd->rr_ttl[0] = newd->ttl;
 645         msg->rep->ttl = newd->ttl;
 646         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(newd->ttl);
 647         sldns_write_uint16(newd->rr_data[0], newlen);
 648         memmove(newd->rr_data[0] + sizeof(uint16_t), newname, newlen);
 649         msg->rep->an_numrrsets ++;
 650         msg->rep->rrset_count ++;
 651         return msg;
 652 }
 653
 654 /** Fill TYPE_ANY response with some data from cache */
 655 static struct dns_msg*
 656 fill_any(struct module_env* env,
 657         uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
 658         struct regional* region)
 659 {
 660         time_t now = *env->now;
 661         struct dns_msg* msg = NULL;
 662         uint16_t lookup[] = {LDNS_RR_TYPE_A, LDNS_RR_TYPE_AAAA,
 663                 LDNS_RR_TYPE_MX, LDNS_RR_TYPE_SOA, LDNS_RR_TYPE_NS,
 664                 LDNS_RR_TYPE_DNAME, 0};
 665         int i, num=6; /* number of RR types to look up */
 666         log_assert(lookup[num] == 0);
 667
 668         for(i=0; i<num; i++) {
 669                 /* look up this RR for inclusion in type ANY response */
 670                 struct ub_packed_rrset_key* rrset = rrset_cache_lookup(
 671                         env->rrset_cache, qname, qnamelen, lookup[i],
 672                         qclass, 0, now, 0);
 673                 struct packed_rrset_data *d;
 674                 if(!rrset)
 675                         continue;
 676
 677                 /* only if rrset from answer section */
 678                 d = (struct packed_rrset_data*)rrset->entry.data;
 679                 if(d->trust == rrset_trust_add_noAA ||
 680                         d->trust == rrset_trust_auth_noAA ||
 681                         d->trust == rrset_trust_add_AA ||
 682                         d->trust == rrset_trust_auth_AA) {
 683                         lock_rw_unlock(&rrset->entry.lock);
 684                         continue;
 685                 }
 686
 687                 /* create msg if none */
 688                 if(!msg) {
 689                         msg = dns_msg_create(qname, qnamelen, qtype, qclass,
 690                                 region, (size_t)(num-i));
 691                         if(!msg) {
 692                                 lock_rw_unlock(&rrset->entry.lock);
 693                                 return NULL;
 694                         }
 695                 }
 696
 697                 /* add RRset to response */
 698                 if(!dns_msg_ansadd(msg, region, rrset, now)) {
 699                         lock_rw_unlock(&rrset->entry.lock);
 700                         return NULL;
 701                 }
 702                 lock_rw_unlock(&rrset->entry.lock);
 703         }
 704         return msg;
 705 }
 706
 707 struct dns_msg*
 708 dns_cache_lookup(struct module_env* env,
 709         uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
 710         uint16_t flags, struct regional* region, struct regional* scratch)
 711 {
 712         struct lruhash_entry* e;
 713         struct query_info k;
 714         hashvalue_type h;
 715         time_t now = *env->now;
 716         struct ub_packed_rrset_key* rrset;
 717
 718         /* lookup first, this has both NXdomains and ANSWER responses */
 719         k.qname = qname;
 720         k.qname_len = qnamelen;
 721         k.qtype = qtype;
 722         k.qclass = qclass;
 723         k.local_alias = NULL;
 724         h = query_info_hash(&k, flags);
 725         e = slabhash_lookup(env->msg_cache, h, &k, 0);
 726         if(e) {
 727                 struct msgreply_entry* key = (struct msgreply_entry*)e->key;
 728                 struct reply_info* data = (struct reply_info*)e->data;
 729                 struct dns_msg* msg = tomsg(env, &key->key, data, region, now,
 730                         scratch);
 731                 if(msg) {
 732                         lock_rw_unlock(&e->lock);
 733                         return msg;
 734                 }
 735                 /* could be msg==NULL; due to TTL or not all rrsets available */
 736                 lock_rw_unlock(&e->lock);
 737         }
 738
 739         /* see if a DNAME exists. Checked for first, to enforce that DNAMEs
 740          * are more important, the CNAME is resynthesized and thus
 741          * consistent with the DNAME */
 742         if( (rrset=find_closest_of_type(env, qname, qnamelen, qclass, now,
 743                 LDNS_RR_TYPE_DNAME, 1))) {
 744                 /* synthesize a DNAME+CNAME message based on this */
 745                 struct dns_msg* msg = synth_dname_msg(rrset, region, now, &k);
 746                 if(msg) {
 747                         lock_rw_unlock(&rrset->entry.lock);
 748                         return msg;
 749                 }
 750                 lock_rw_unlock(&rrset->entry.lock);
 751         }
 752
 753         /* see if we have CNAME for this domain,
 754          * but not for DS records (which are part of the parent) */
 755         if( qtype != LDNS_RR_TYPE_DS &&
 756            (rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen,
 757                 LDNS_RR_TYPE_CNAME, qclass, 0, now, 0))) {
 758                 struct dns_msg* msg = rrset_msg(rrset, region, now, &k);
 759                 if(msg) {
 760                         lock_rw_unlock(&rrset->entry.lock);
 761                         return msg;
 762                 }
 763                 lock_rw_unlock(&rrset->entry.lock);
 764         }
 765
 766         /* construct DS, DNSKEY, DLV messages from rrset cache. */
 767         if((qtype == LDNS_RR_TYPE_DS || qtype == LDNS_RR_TYPE_DNSKEY ||
 768                 qtype == LDNS_RR_TYPE_DLV) &&
 769                 (rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen,
 770                 qtype, qclass, 0, now, 0))) {
 771                 /* if the rrset is from the additional section, and the
 772                  * signatures have fallen off, then do not synthesize a msg
 773                  * instead, allow a full query for signed results to happen.
 774                  * Forego all rrset data from additional section, because
 775                  * some signatures may not be present and cause validation
 776                  * failure.
 777                  */
 778                 struct packed_rrset_data *d = (struct packed_rrset_data*)
 779                         rrset->entry.data;
 780                 if(d->trust != rrset_trust_add_noAA &&
 781                         d->trust != rrset_trust_add_AA &&
 782                         (qtype == LDNS_RR_TYPE_DS ||
 783                                 (d->trust != rrset_trust_auth_noAA
 784                                 && d->trust != rrset_trust_auth_AA) )) {
 785                         struct dns_msg* msg = rrset_msg(rrset, region, now, &k);
 786                         if(msg) {
 787                                 lock_rw_unlock(&rrset->entry.lock);
 788                                 return msg;
 789                         }
 790                 }
 791                 lock_rw_unlock(&rrset->entry.lock);
 792         }
 793
 794         /* stop downwards cache search on NXDOMAIN.
 795          * Empty nonterminals are NOERROR, so an NXDOMAIN for foo
 796          * means bla.foo also does not exist.  The DNSSEC proofs are
 797          * the same.  We search upwards for NXDOMAINs. */
 798         if(env->cfg->harden_below_nxdomain)
 799             while(!dname_is_root(k.qname)) {
 800                 dname_remove_label(&k.qname, &k.qname_len);
 801                 h = query_info_hash(&k, flags);
 802                 e = slabhash_lookup(env->msg_cache, h, &k, 0);
 803                 if(!e && k.qtype != LDNS_RR_TYPE_A &&
 804                         env->cfg->qname_minimisation) {
 805                         k.qtype = LDNS_RR_TYPE_A;
 806                         h = query_info_hash(&k, flags);
 807                         e = slabhash_lookup(env->msg_cache, h, &k, 0);
 808                 }
 809                 if(e) {
 810                         struct reply_info* data = (struct reply_info*)e->data;
 811                         struct dns_msg* msg;
 812                         if(FLAGS_GET_RCODE(data->flags) == LDNS_RCODE_NXDOMAIN
 813                           && data->security == sec_status_secure
 814                           && (msg=tomsg(env, &k, data, region, now, scratch))){
 815                                 lock_rw_unlock(&e->lock);
 816                                 msg->qinfo.qname=qname;
 817                                 msg->qinfo.qname_len=qnamelen;
 818                                 /* check that DNSSEC really works out */
 819                                 msg->rep->security = sec_status_unchecked;
 820                                 return msg;
 821                         }
 822                         lock_rw_unlock(&e->lock);
 823                 }
 824                 k.qtype = qtype;
 825             }
 826
 827         /* fill common RR types for ANY response to avoid requery */
 828         if(qtype == LDNS_RR_TYPE_ANY) {
 829                 return fill_any(env, qname, qnamelen, qtype, qclass, region);
 830         }
 831
 832         return NULL;
 833 }
 834
 835 int
 836 dns_cache_store(struct module_env* env, struct query_info* msgqinf,
 837         struct reply_info* msgrep, int is_referral, time_t leeway, int pside,
 838         struct regional* region, uint16_t flags)
 839 {
 840         struct reply_info* rep = NULL;
 841         /* alloc, malloc properly (not in region, like msg is) */
 842         rep = reply_info_copy(msgrep, env->alloc, NULL);
 843         if(!rep)
 844                 return 0;
 845         /* ttl must be relative ;i.e. 0..86400 not  time(0)+86400.
 846          * the env->now is added to message and RRsets in this routine. */
 847         /* the leeway is used to invalidate other rrsets earlier */
 848
 849         if(is_referral) {
 850                 /* store rrsets */
 851                 struct rrset_ref ref;
 852                 size_t i;
 853                 for(i=0; i<rep->rrset_count; i++) {
 854                         packed_rrset_ttl_add((struct packed_rrset_data*)
 855                                 rep->rrsets[i]->entry.data, *env->now);
 856                         ref.key = rep->rrsets[i];
 857                         ref.id = rep->rrsets[i]->id;
 858                         /*ignore ret: it was in the cache, ref updated */
 859                         /* no leeway for typeNS */
 860                         (void)rrset_cache_update(env->rrset_cache, &ref,
 861                                 env->alloc, *env->now +
 862                                 ((ntohs(ref.key->rk.type)==LDNS_RR_TYPE_NS
 863                                  && !pside) ? 0:leeway));
 864                 }
 865                 free(rep);
 866                 return 1;
 867         } else {
 868                 /* store msg, and rrsets */
 869                 struct query_info qinf;
 870                 hashvalue_type h;
 871
 872                 qinf = *msgqinf;
 873                 qinf.qname = memdup(msgqinf->qname, msgqinf->qname_len);
 874                 if(!qinf.qname) {
 875                         reply_info_parsedelete(rep, env->alloc);
 876                         return 0;
 877                 }
 878                 /* fixup flags to be sensible for a reply based on the cache */
 879                 /* this module means that RA is available. It is an answer QR.
 880                  * Not AA from cache. Not CD in cache (depends on client bit). */
 881                 rep->flags |= (BIT_RA | BIT_QR);
 882                 rep->flags &= ~(BIT_AA | BIT_CD);
 883                 h = query_info_hash(&qinf, flags);
 884                 dns_cache_store_msg(env, &qinf, h, rep, leeway, pside, msgrep,
 885                         region);
 886                 /* qname is used inside query_info_entrysetup, and set to
 887                  * NULL. If it has not been used, free it. free(0) is safe. */
 888                 free(qinf.qname);
 889         }
 890         return 1;
 891 }
 892
 893 int
 894 dns_cache_prefetch_adjust(struct module_env* env, struct query_info* qinfo,
 895         time_t adjust, uint16_t flags)
 896 {
 897         struct msgreply_entry* msg;
 898         msg = msg_cache_lookup(env, qinfo->qname, qinfo->qname_len,
 899                 qinfo->qtype, qinfo->qclass, flags, *env->now, 1);
 900         if(msg) {
 901                 struct reply_info* rep = (struct reply_info*)msg->entry.data;
 902                 if(rep) {
 903                         rep->prefetch_ttl += adjust;
 904                         lock_rw_unlock(&msg->entry.lock);
 905                         return 1;
 906                 }
 907                 lock_rw_unlock(&msg->entry.lock);
 908         }
 909         return 0;
 910 }