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 "ldns/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_t 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, time_t now, int wr)
 188 {
 189         struct lruhash_entry* e;
 190         struct query_info k;
 191         hashvalue_t h;
 192
 193         k.qname = qname;
 194         k.qname_len = qnamelen;
 195         k.qtype = qtype;
 196         k.qclass = qclass;
 197         h = query_info_hash(&k);
 198         e = slabhash_lookup(env->msg_cache, h, &k, wr);
 199
 200         if(!e) return NULL;
 201         if( now > ((struct reply_info*)e->data)->ttl ) {
 202                 lock_rw_unlock(&e->lock);
 203                 return NULL;
 204         }
 205         return (struct msgreply_entry*)e->key;
 206 }
 207
 208 /** find and add A and AAAA records for nameservers in delegpt */
 209 static int
 210 find_add_addrs(struct module_env* env, uint16_t qclass,
 211         struct regional* region, struct delegpt* dp, time_t now,
 212         struct dns_msg** msg)
 213 {
 214         struct delegpt_ns* ns;
 215         struct msgreply_entry* neg;
 216         struct ub_packed_rrset_key* akey;
 217         for(ns = dp->nslist; ns; ns = ns->next) {
 218                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 219                         ns->namelen, LDNS_RR_TYPE_A, qclass, 0, now, 0);
 220                 if(akey) {
 221                         if(!delegpt_add_rrset_A(dp, region, akey, 0)) {
 222                                 lock_rw_unlock(&akey->entry.lock);
 223                                 return 0;
 224                         }
 225                         if(msg)
 226                                 addr_to_additional(akey, region, *msg, now);
 227                         lock_rw_unlock(&akey->entry.lock);
 228                 } else {
 229                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 230                                 LDNS_RR_TYPE_A, qclass, now, 0);
 231                         if(neg) {
 232                                 delegpt_add_neg_msg(dp, neg);
 233                                 lock_rw_unlock(&neg->entry.lock);
 234                         }
 235                 }
 236                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 237                         ns->namelen, LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
 238                 if(akey) {
 239                         if(!delegpt_add_rrset_AAAA(dp, region, akey, 0)) {
 240                                 lock_rw_unlock(&akey->entry.lock);
 241                                 return 0;
 242                         }
 243                         if(msg)
 244                                 addr_to_additional(akey, region, *msg, now);
 245                         lock_rw_unlock(&akey->entry.lock);
 246                 } else {
 247                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 248                                 LDNS_RR_TYPE_AAAA, qclass, now, 0);
 249                         if(neg) {
 250                                 delegpt_add_neg_msg(dp, neg);
 251                                 lock_rw_unlock(&neg->entry.lock);
 252                         }
 253                 }
 254         }
 255         return 1;
 256 }
 257
 258 /** find and add A and AAAA records for missing nameservers in delegpt */
 259 int
 260 cache_fill_missing(struct module_env* env, uint16_t qclass,
 261         struct regional* region, struct delegpt* dp)
 262 {
 263         struct delegpt_ns* ns;
 264         struct msgreply_entry* neg;
 265         struct ub_packed_rrset_key* akey;
 266         time_t now = *env->now;
 267         for(ns = dp->nslist; ns; ns = ns->next) {
 268                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 269                         ns->namelen, LDNS_RR_TYPE_A, qclass, 0, now, 0);
 270                 if(akey) {
 271                         if(!delegpt_add_rrset_A(dp, region, akey, ns->lame)) {
 272                                 lock_rw_unlock(&akey->entry.lock);
 273                                 return 0;
 274                         }
 275                         log_nametypeclass(VERB_ALGO, "found in cache",
 276                                 ns->name, LDNS_RR_TYPE_A, qclass);
 277                         lock_rw_unlock(&akey->entry.lock);
 278                 } else {
 279                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 280                                 LDNS_RR_TYPE_A, qclass, now, 0);
 281                         if(neg) {
 282                                 delegpt_add_neg_msg(dp, neg);
 283                                 lock_rw_unlock(&neg->entry.lock);
 284                         }
 285                 }
 286                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 287                         ns->namelen, LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
 288                 if(akey) {
 289                         if(!delegpt_add_rrset_AAAA(dp, region, akey, ns->lame)) {
 290                                 lock_rw_unlock(&akey->entry.lock);
 291                                 return 0;
 292                         }
 293                         log_nametypeclass(VERB_ALGO, "found in cache",
 294                                 ns->name, LDNS_RR_TYPE_AAAA, qclass);
 295                         lock_rw_unlock(&akey->entry.lock);
 296                 } else {
 297                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 298                                 LDNS_RR_TYPE_AAAA, qclass, now, 0);
 299                         if(neg) {
 300                                 delegpt_add_neg_msg(dp, neg);
 301                                 lock_rw_unlock(&neg->entry.lock);
 302                         }
 303                 }
 304         }
 305         return 1;
 306 }
 307
 308 /** find and add DS or NSEC to delegation msg */
 309 static void
 310 find_add_ds(struct module_env* env, struct regional* region,
 311         struct dns_msg* msg, struct delegpt* dp, time_t now)
 312 {
 313         /* Lookup the DS or NSEC at the delegation point. */
 314         struct ub_packed_rrset_key* rrset = rrset_cache_lookup(
 315                 env->rrset_cache, dp->name, dp->namelen, LDNS_RR_TYPE_DS,
 316                 msg->qinfo.qclass, 0, now, 0);
 317         if(!rrset) {
 318                 /* NOTE: this won't work for alternate NSEC schemes
 319                  *      (opt-in, NSEC3) */
 320                 rrset = rrset_cache_lookup(env->rrset_cache, dp->name,
 321                         dp->namelen, LDNS_RR_TYPE_NSEC, msg->qinfo.qclass,
 322                         0, now, 0);
 323                 /* Note: the PACKED_RRSET_NSEC_AT_APEX flag is not used.
 324                  * since this is a referral, we need the NSEC at the parent
 325                  * side of the zone cut, not the NSEC at apex side. */
 326                 if(rrset && nsec_has_type(rrset, LDNS_RR_TYPE_DS)) {
 327                         lock_rw_unlock(&rrset->entry.lock);
 328                         rrset = NULL; /* discard wrong NSEC */
 329                 }
 330         }
 331         if(rrset) {
 332                 /* add it to auth section. This is the second rrset. */
 333                 if((msg->rep->rrsets[msg->rep->rrset_count] =
 334                         packed_rrset_copy_region(rrset, region, now))) {
 335                         msg->rep->ns_numrrsets++;
 336                         msg->rep->rrset_count++;
 337                 }
 338                 lock_rw_unlock(&rrset->entry.lock);
 339         }
 340 }
 341
 342 struct dns_msg*
 343 dns_msg_create(uint8_t* qname, size_t qnamelen, uint16_t qtype,
 344         uint16_t qclass, struct regional* region, size_t capacity)
 345 {
 346         struct dns_msg* msg = (struct dns_msg*)regional_alloc(region,
 347                 sizeof(struct dns_msg));
 348         if(!msg)
 349                 return NULL;
 350         msg->qinfo.qname = regional_alloc_init(region, qname, qnamelen);
 351         if(!msg->qinfo.qname)
 352                 return NULL;
 353         msg->qinfo.qname_len = qnamelen;
 354         msg->qinfo.qtype = qtype;
 355         msg->qinfo.qclass = qclass;
 356         /* non-packed reply_info, because it needs to grow the array */
 357         msg->rep = (struct reply_info*)regional_alloc_zero(region,
 358                 sizeof(struct reply_info)-sizeof(struct rrset_ref));
 359         if(!msg->rep)
 360                 return NULL;
 361         msg->rep->flags = BIT_QR; /* with QR, no AA */
 362         msg->rep->qdcount = 1;
 363         msg->rep->rrsets = (struct ub_packed_rrset_key**)
 364                 regional_alloc(region,
 365                 capacity*sizeof(struct ub_packed_rrset_key*));
 366         if(!msg->rep->rrsets)
 367                 return NULL;
 368         return msg;
 369 }
 370
 371 int
 372 dns_msg_authadd(struct dns_msg* msg, struct regional* region,
 373         struct ub_packed_rrset_key* rrset, time_t now)
 374 {
 375         if(!(msg->rep->rrsets[msg->rep->rrset_count++] =
 376                 packed_rrset_copy_region(rrset, region, now)))
 377                 return 0;
 378         msg->rep->ns_numrrsets++;
 379         return 1;
 380 }
 381
 382 struct delegpt*
 383 dns_cache_find_delegation(struct module_env* env, uint8_t* qname,
 384         size_t qnamelen, uint16_t qtype, uint16_t qclass,
 385         struct regional* region, struct dns_msg** msg, time_t now)
 386 {
 387         /* try to find closest NS rrset */
 388         struct ub_packed_rrset_key* nskey;
 389         struct packed_rrset_data* nsdata;
 390         struct delegpt* dp;
 391
 392         nskey = find_closest_of_type(env, qname, qnamelen, qclass, now,
 393                 LDNS_RR_TYPE_NS, 0);
 394         if(!nskey) /* hope the caller has hints to prime or something */
 395                 return NULL;
 396         nsdata = (struct packed_rrset_data*)nskey->entry.data;
 397         /* got the NS key, create delegation point */
 398         dp = delegpt_create(region);
 399         if(!dp || !delegpt_set_name(dp, region, nskey->rk.dname)) {
 400                 lock_rw_unlock(&nskey->entry.lock);
 401                 log_err("find_delegation: out of memory");
 402                 return NULL;
 403         }
 404         /* create referral message */
 405         if(msg) {
 406                 /* allocate the array to as much as we could need:
 407                  *      NS rrset + DS/NSEC rrset +
 408                  *      A rrset for every NS RR
 409                  *      AAAA rrset for every NS RR
 410                  */
 411                 *msg = dns_msg_create(qname, qnamelen, qtype, qclass, region,
 412                         2 + nsdata->count*2);
 413                 if(!*msg || !dns_msg_authadd(*msg, region, nskey, now)) {
 414                         lock_rw_unlock(&nskey->entry.lock);
 415                         log_err("find_delegation: out of memory");
 416                         return NULL;
 417                 }
 418         }
 419         if(!delegpt_rrset_add_ns(dp, region, nskey, 0))
 420                 log_err("find_delegation: addns out of memory");
 421         lock_rw_unlock(&nskey->entry.lock); /* first unlock before next lookup*/
 422         /* find and add DS/NSEC (if any) */
 423         if(msg)
 424                 find_add_ds(env, region, *msg, dp, now);
 425         /* find and add A entries */
 426         if(!find_add_addrs(env, qclass, region, dp, now, msg))
 427                 log_err("find_delegation: addrs out of memory");
 428         return dp;
 429 }
 430
 431 /** allocate dns_msg from query_info and reply_info */
 432 static struct dns_msg*
 433 gen_dns_msg(struct regional* region, struct query_info* q, size_t num)
 434 {
 435         struct dns_msg* msg = (struct dns_msg*)regional_alloc(region,
 436                 sizeof(struct dns_msg));
 437         if(!msg)
 438                 return NULL;
 439         memcpy(&msg->qinfo, q, sizeof(struct query_info));
 440         msg->qinfo.qname = regional_alloc_init(region, q->qname, q->qname_len);
 441         if(!msg->qinfo.qname)
 442                 return NULL;
 443         /* allocate replyinfo struct and rrset key array separately */
 444         msg->rep = (struct reply_info*)regional_alloc(region,
 445                 sizeof(struct reply_info) - sizeof(struct rrset_ref));
 446         if(!msg->rep)
 447                 return NULL;
 448         msg->rep->rrsets = (struct ub_packed_rrset_key**)
 449                 regional_alloc(region,
 450                 num * sizeof(struct ub_packed_rrset_key*));
 451         if(!msg->rep->rrsets)
 452                 return NULL;
 453         return msg;
 454 }
 455
 456 /** generate dns_msg from cached message */
 457 static struct dns_msg*
 458 tomsg(struct module_env* env, struct query_info* q, struct reply_info* r,
 459         struct regional* region, time_t now, struct regional* scratch)
 460 {
 461         struct dns_msg* msg;
 462         size_t i;
 463         if(now > r->ttl)
 464                 return NULL;
 465         msg = gen_dns_msg(region, q, r->rrset_count);
 466         if(!msg)
 467                 return NULL;
 468         msg->rep->flags = r->flags;
 469         msg->rep->qdcount = r->qdcount;
 470         msg->rep->ttl = r->ttl - now;
 471         if(r->prefetch_ttl > now)
 472                 msg->rep->prefetch_ttl = r->prefetch_ttl - now;
 473         else    msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 474         msg->rep->security = r->security;
 475         msg->rep->an_numrrsets = r->an_numrrsets;
 476         msg->rep->ns_numrrsets = r->ns_numrrsets;
 477         msg->rep->ar_numrrsets = r->ar_numrrsets;
 478         msg->rep->rrset_count = r->rrset_count;
 479         msg->rep->authoritative = r->authoritative;
 480         if(!rrset_array_lock(r->ref, r->rrset_count, now))
 481                 return NULL;
 482         if(r->an_numrrsets > 0 && (r->rrsets[0]->rk.type == htons(
 483                 LDNS_RR_TYPE_CNAME) || r->rrsets[0]->rk.type == htons(
 484                 LDNS_RR_TYPE_DNAME)) && !reply_check_cname_chain(r)) {
 485                 /* cname chain is now invalid, reconstruct msg */
 486                 rrset_array_unlock(r->ref, r->rrset_count);
 487                 return NULL;
 488         }
 489         if(r->security == sec_status_secure && !reply_all_rrsets_secure(r)) {
 490                 /* message rrsets have changed status, revalidate */
 491                 rrset_array_unlock(r->ref, r->rrset_count);
 492                 return NULL;
 493         }
 494         for(i=0; i<msg->rep->rrset_count; i++) {
 495                 msg->rep->rrsets[i] = packed_rrset_copy_region(r->rrsets[i],
 496                         region, now);
 497                 if(!msg->rep->rrsets[i]) {
 498                         rrset_array_unlock(r->ref, r->rrset_count);
 499                         return NULL;
 500                 }
 501         }
 502         rrset_array_unlock_touch(env->rrset_cache, scratch, r->ref,
 503                 r->rrset_count);
 504         return msg;
 505 }
 506
 507 /** synthesize RRset-only response from cached RRset item */
 508 static struct dns_msg*
 509 rrset_msg(struct ub_packed_rrset_key* rrset, struct regional* region,
 510         time_t now, struct query_info* q)
 511 {
 512         struct dns_msg* msg;
 513         struct packed_rrset_data* d = (struct packed_rrset_data*)
 514                 rrset->entry.data;
 515         if(now > d->ttl)
 516                 return NULL;
 517         msg = gen_dns_msg(region, q, 1); /* only the CNAME (or other) RRset */
 518         if(!msg)
 519                 return NULL;
 520         msg->rep->flags = BIT_QR; /* reply, no AA, no error */
 521         msg->rep->authoritative = 0; /* reply stored in cache can't be authoritative */
 522         msg->rep->qdcount = 1;
 523         msg->rep->ttl = d->ttl - now;
 524         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 525         msg->rep->security = sec_status_unchecked;
 526         msg->rep->an_numrrsets = 1;
 527         msg->rep->ns_numrrsets = 0;
 528         msg->rep->ar_numrrsets = 0;
 529         msg->rep->rrset_count = 1;
 530         msg->rep->rrsets[0] = packed_rrset_copy_region(rrset, region, now);
 531         if(!msg->rep->rrsets[0]) /* copy CNAME */
 532                 return NULL;
 533         return msg;
 534 }
 535
 536 /** synthesize DNAME+CNAME response from cached DNAME item */
 537 static struct dns_msg*
 538 synth_dname_msg(struct ub_packed_rrset_key* rrset, struct regional* region,
 539         time_t now, struct query_info* q)
 540 {
 541         struct dns_msg* msg;
 542         struct ub_packed_rrset_key* ck;
 543         struct packed_rrset_data* newd, *d = (struct packed_rrset_data*)
 544                 rrset->entry.data;
 545         uint8_t* newname, *dtarg = NULL;
 546         size_t newlen, dtarglen;
 547         if(now > d->ttl)
 548                 return NULL;
 549         /* only allow validated (with DNSSEC) DNAMEs used from cache
 550          * for insecure DNAMEs, query again. */
 551         if(d->security != sec_status_secure)
 552                 return NULL;
 553         msg = gen_dns_msg(region, q, 2); /* DNAME + CNAME RRset */
 554         if(!msg)
 555                 return NULL;
 556         msg->rep->flags = BIT_QR; /* reply, no AA, no error */
 557         msg->rep->authoritative = 0; /* reply stored in cache can't be authoritative */
 558         msg->rep->qdcount = 1;
 559         msg->rep->ttl = d->ttl - now;
 560         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 561         msg->rep->security = sec_status_unchecked;
 562         msg->rep->an_numrrsets = 1;
 563         msg->rep->ns_numrrsets = 0;
 564         msg->rep->ar_numrrsets = 0;
 565         msg->rep->rrset_count = 1;
 566         msg->rep->rrsets[0] = packed_rrset_copy_region(rrset, region, now);
 567         if(!msg->rep->rrsets[0]) /* copy DNAME */
 568                 return NULL;
 569         /* synth CNAME rrset */
 570         get_cname_target(rrset, &dtarg, &dtarglen);
 571         if(!dtarg)
 572                 return NULL;
 573         newlen = q->qname_len + dtarglen - rrset->rk.dname_len;
 574         if(newlen > LDNS_MAX_DOMAINLEN) {
 575                 msg->rep->flags |= LDNS_RCODE_YXDOMAIN;
 576                 return msg;
 577         }
 578         newname = (uint8_t*)regional_alloc(region, newlen);
 579         if(!newname)
 580                 return NULL;
 581         /* new name is concatenation of qname front (without DNAME owner)
 582          * and DNAME target name */
 583         memcpy(newname, q->qname, q->qname_len-rrset->rk.dname_len);
 584         memmove(newname+(q->qname_len-rrset->rk.dname_len), dtarg, dtarglen);
 585         /* create rest of CNAME rrset */
 586         ck = (struct ub_packed_rrset_key*)regional_alloc(region,
 587                 sizeof(struct ub_packed_rrset_key));
 588         if(!ck)
 589                 return NULL;
 590         memset(&ck->entry, 0, sizeof(ck->entry));
 591         msg->rep->rrsets[1] = ck;
 592         ck->entry.key = ck;
 593         ck->rk.type = htons(LDNS_RR_TYPE_CNAME);
 594         ck->rk.rrset_class = rrset->rk.rrset_class;
 595         ck->rk.flags = 0;
 596         ck->rk.dname = regional_alloc_init(region, q->qname, q->qname_len);
 597         if(!ck->rk.dname)
 598                 return NULL;
 599         ck->rk.dname_len = q->qname_len;
 600         ck->entry.hash = rrset_key_hash(&ck->rk);
 601         newd = (struct packed_rrset_data*)regional_alloc_zero(region,
 602                 sizeof(struct packed_rrset_data) + sizeof(size_t) +
 603                 sizeof(uint8_t*) + sizeof(time_t) + sizeof(uint16_t)
 604                 + newlen);
 605         if(!newd)
 606                 return NULL;
 607         ck->entry.data = newd;
 608         newd->ttl = 0; /* 0 for synthesized CNAME TTL */
 609         newd->count = 1;
 610         newd->rrsig_count = 0;
 611         newd->trust = rrset_trust_ans_noAA;
 612         newd->rr_len = (size_t*)((uint8_t*)newd +
 613                 sizeof(struct packed_rrset_data));
 614         newd->rr_len[0] = newlen + sizeof(uint16_t);
 615         packed_rrset_ptr_fixup(newd);
 616         newd->rr_ttl[0] = newd->ttl;
 617         msg->rep->ttl = newd->ttl;
 618         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(newd->ttl);
 619         sldns_write_uint16(newd->rr_data[0], newlen);
 620         memmove(newd->rr_data[0] + sizeof(uint16_t), newname, newlen);
 621         msg->rep->an_numrrsets ++;
 622         msg->rep->rrset_count ++;
 623         return msg;
 624 }
 625
 626 struct dns_msg*
 627 dns_cache_lookup(struct module_env* env,
 628         uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
 629         struct regional* region, struct regional* scratch)
 630 {
 631         struct lruhash_entry* e;
 632         struct query_info k;
 633         hashvalue_t h;
 634         time_t now = *env->now;
 635         struct ub_packed_rrset_key* rrset;
 636
 637         /* lookup first, this has both NXdomains and ANSWER responses */
 638         k.qname = qname;
 639         k.qname_len = qnamelen;
 640         k.qtype = qtype;
 641         k.qclass = qclass;
 642         h = query_info_hash(&k);
 643         e = slabhash_lookup(env->msg_cache, h, &k, 0);
 644         if(e) {
 645                 struct msgreply_entry* key = (struct msgreply_entry*)e->key;
 646                 struct reply_info* data = (struct reply_info*)e->data;
 647                 struct dns_msg* msg = tomsg(env, &key->key, data, region, now,
 648                         scratch);
 649                 if(msg) {
 650                         lock_rw_unlock(&e->lock);
 651                         return msg;
 652                 }
 653                 /* could be msg==NULL; due to TTL or not all rrsets available */
 654                 lock_rw_unlock(&e->lock);
 655         }
 656
 657         /* see if a DNAME exists. Checked for first, to enforce that DNAMEs
 658          * are more important, the CNAME is resynthesized and thus
 659          * consistent with the DNAME */
 660         if( (rrset=find_closest_of_type(env, qname, qnamelen, qclass, now,
 661                 LDNS_RR_TYPE_DNAME, 1))) {
 662                 /* synthesize a DNAME+CNAME message based on this */
 663                 struct dns_msg* msg = synth_dname_msg(rrset, region, now, &k);
 664                 if(msg) {
 665                         lock_rw_unlock(&rrset->entry.lock);
 666                         return msg;
 667                 }
 668                 lock_rw_unlock(&rrset->entry.lock);
 669         }
 670
 671         /* see if we have CNAME for this domain,
 672          * but not for DS records (which are part of the parent) */
 673         if( qtype != LDNS_RR_TYPE_DS &&
 674            (rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen,
 675                 LDNS_RR_TYPE_CNAME, qclass, 0, now, 0))) {
 676                 struct dns_msg* msg = rrset_msg(rrset, region, now, &k);
 677                 if(msg) {
 678                         lock_rw_unlock(&rrset->entry.lock);
 679                         return msg;
 680                 }
 681                 lock_rw_unlock(&rrset->entry.lock);
 682         }
 683
 684         /* construct DS, DNSKEY, DLV messages from rrset cache. */
 685         if((qtype == LDNS_RR_TYPE_DS || qtype == LDNS_RR_TYPE_DNSKEY ||
 686                 qtype == LDNS_RR_TYPE_DLV) &&
 687                 (rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen,
 688                 qtype, qclass, 0, now, 0))) {
 689                 /* if the rrset is from the additional section, and the
 690                  * signatures have fallen off, then do not synthesize a msg
 691                  * instead, allow a full query for signed results to happen.
 692                  * Forego all rrset data from additional section, because
 693                  * some signatures may not be present and cause validation
 694                  * failure.
 695                  */
 696                 struct packed_rrset_data *d = (struct packed_rrset_data*)
 697                         rrset->entry.data;
 698                 if(d->trust != rrset_trust_add_noAA &&
 699                         d->trust != rrset_trust_add_AA &&
 700                         (qtype == LDNS_RR_TYPE_DS ||
 701                                 (d->trust != rrset_trust_auth_noAA
 702                                 && d->trust != rrset_trust_auth_AA) )) {
 703                         struct dns_msg* msg = rrset_msg(rrset, region, now, &k);
 704                         if(msg) {
 705                                 lock_rw_unlock(&rrset->entry.lock);
 706                                 return msg;
 707                         }
 708                 }
 709                 lock_rw_unlock(&rrset->entry.lock);
 710         }
 711
 712         /* stop downwards cache search on NXDOMAIN.
 713          * Empty nonterminals are NOERROR, so an NXDOMAIN for foo
 714          * means bla.foo also does not exist.  The DNSSEC proofs are
 715          * the same.  We search upwards for NXDOMAINs. */
 716         if(env->cfg->harden_below_nxdomain)
 717             while(!dname_is_root(k.qname)) {
 718                 dname_remove_label(&k.qname, &k.qname_len);
 719                 h = query_info_hash(&k);
 720                 e = slabhash_lookup(env->msg_cache, h, &k, 0);
 721                 if(e) {
 722                         struct reply_info* data = (struct reply_info*)e->data;
 723                         struct dns_msg* msg;
 724                         if(FLAGS_GET_RCODE(data->flags) == LDNS_RCODE_NXDOMAIN
 725                           && data->security == sec_status_secure
 726                           && (msg=tomsg(env, &k, data, region, now, scratch))){
 727                                 lock_rw_unlock(&e->lock);
 728                                 msg->qinfo.qname=qname;
 729                                 msg->qinfo.qname_len=qnamelen;
 730                                 /* check that DNSSEC really works out */
 731                                 msg->rep->security = sec_status_unchecked;
 732                                 return msg;
 733                         }
 734                         lock_rw_unlock(&e->lock);
 735                 }
 736         }
 737
 738         return NULL;
 739 }
 740
 741 int
 742 dns_cache_store(struct module_env* env, struct query_info* msgqinf,
 743         struct reply_info* msgrep, int is_referral, time_t leeway, int pside,
 744         struct regional* region)
 745 {
 746         struct reply_info* rep = NULL;
 747         /* alloc, malloc properly (not in region, like msg is) */
 748         rep = reply_info_copy(msgrep, env->alloc, NULL);
 749         if(!rep)
 750                 return 0;
 751         /* ttl must be relative ;i.e. 0..86400 not  time(0)+86400.
 752          * the env->now is added to message and RRsets in this routine. */
 753         /* the leeway is used to invalidate other rrsets earlier */
 754
 755         if(is_referral) {
 756                 /* store rrsets */
 757                 struct rrset_ref ref;
 758                 size_t i;
 759                 for(i=0; i<rep->rrset_count; i++) {
 760                         packed_rrset_ttl_add((struct packed_rrset_data*)
 761                                 rep->rrsets[i]->entry.data, *env->now);
 762                         ref.key = rep->rrsets[i];
 763                         ref.id = rep->rrsets[i]->id;
 764                         /*ignore ret: it was in the cache, ref updated */
 765                         /* no leeway for typeNS */
 766                         (void)rrset_cache_update(env->rrset_cache, &ref,
 767                                 env->alloc, *env->now +
 768                                 ((ntohs(ref.key->rk.type)==LDNS_RR_TYPE_NS
 769                                  && !pside) ? 0:leeway));
 770                 }
 771                 free(rep);
 772                 return 1;
 773         } else {
 774                 /* store msg, and rrsets */
 775                 struct query_info qinf;
 776                 hashvalue_t h;
 777
 778                 qinf = *msgqinf;
 779                 qinf.qname = memdup(msgqinf->qname, msgqinf->qname_len);
 780                 if(!qinf.qname) {
 781                         reply_info_parsedelete(rep, env->alloc);
 782                         return 0;
 783                 }
 784                 /* fixup flags to be sensible for a reply based on the cache */
 785                 /* this module means that RA is available. It is an answer QR.
 786                  * Not AA from cache. Not CD in cache (depends on client bit). */
 787                 rep->flags |= (BIT_RA | BIT_QR);
 788                 rep->flags &= ~(BIT_AA | BIT_CD);
 789                 h = query_info_hash(&qinf);
 790                 dns_cache_store_msg(env, &qinf, h, rep, leeway, pside, msgrep,
 791                         region);
 792                 /* qname is used inside query_info_entrysetup, and set to
 793                  * NULL. If it has not been used, free it. free(0) is safe. */
 794                 free(qinf.qname);
 795         }
 796         return 1;
 797 }