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, uint16_t flags, 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, flags);
 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                         /* BIT_CD on false because delegpt lookup does
 230                          * not use dns64 translation */
 231                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 232                                 LDNS_RR_TYPE_A, qclass, 0, now, 0);
 233                         if(neg) {
 234                                 delegpt_add_neg_msg(dp, neg);
 235                                 lock_rw_unlock(&neg->entry.lock);
 236                         }
 237                 }
 238                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 239                         ns->namelen, LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
 240                 if(akey) {
 241                         if(!delegpt_add_rrset_AAAA(dp, region, akey, 0)) {
 242                                 lock_rw_unlock(&akey->entry.lock);
 243                                 return 0;
 244                         }
 245                         if(msg)
 246                                 addr_to_additional(akey, region, *msg, now);
 247                         lock_rw_unlock(&akey->entry.lock);
 248                 } else {
 249                         /* BIT_CD on false because delegpt lookup does
 250                          * not use dns64 translation */
 251                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 252                                 LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
 253                         if(neg) {
 254                                 delegpt_add_neg_msg(dp, neg);
 255                                 lock_rw_unlock(&neg->entry.lock);
 256                         }
 257                 }
 258         }
 259         return 1;
 260 }
 261
 262 /** find and add A and AAAA records for missing nameservers in delegpt */
 263 int
 264 cache_fill_missing(struct module_env* env, uint16_t qclass,
 265         struct regional* region, struct delegpt* dp)
 266 {
 267         struct delegpt_ns* ns;
 268         struct msgreply_entry* neg;
 269         struct ub_packed_rrset_key* akey;
 270         time_t now = *env->now;
 271         for(ns = dp->nslist; ns; ns = ns->next) {
 272                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 273                         ns->namelen, LDNS_RR_TYPE_A, qclass, 0, now, 0);
 274                 if(akey) {
 275                         if(!delegpt_add_rrset_A(dp, region, akey, ns->lame)) {
 276                                 lock_rw_unlock(&akey->entry.lock);
 277                                 return 0;
 278                         }
 279                         log_nametypeclass(VERB_ALGO, "found in cache",
 280                                 ns->name, LDNS_RR_TYPE_A, qclass);
 281                         lock_rw_unlock(&akey->entry.lock);
 282                 } else {
 283                         /* BIT_CD on false because delegpt lookup does
 284                          * not use dns64 translation */
 285                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 286                                 LDNS_RR_TYPE_A, qclass, 0, now, 0);
 287                         if(neg) {
 288                                 delegpt_add_neg_msg(dp, neg);
 289                                 lock_rw_unlock(&neg->entry.lock);
 290                         }
 291                 }
 292                 akey = rrset_cache_lookup(env->rrset_cache, ns->name,
 293                         ns->namelen, LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
 294                 if(akey) {
 295                         if(!delegpt_add_rrset_AAAA(dp, region, akey, ns->lame)) {
 296                                 lock_rw_unlock(&akey->entry.lock);
 297                                 return 0;
 298                         }
 299                         log_nametypeclass(VERB_ALGO, "found in cache",
 300                                 ns->name, LDNS_RR_TYPE_AAAA, qclass);
 301                         lock_rw_unlock(&akey->entry.lock);
 302                 } else {
 303                         /* BIT_CD on false because delegpt lookup does
 304                          * not use dns64 translation */
 305                         neg = msg_cache_lookup(env, ns->name, ns->namelen,
 306                                 LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
 307                         if(neg) {
 308                                 delegpt_add_neg_msg(dp, neg);
 309                                 lock_rw_unlock(&neg->entry.lock);
 310                         }
 311                 }
 312         }
 313         return 1;
 314 }
 315
 316 /** find and add DS or NSEC to delegation msg */
 317 static void
 318 find_add_ds(struct module_env* env, struct regional* region,
 319         struct dns_msg* msg, struct delegpt* dp, time_t now)
 320 {
 321         /* Lookup the DS or NSEC at the delegation point. */
 322         struct ub_packed_rrset_key* rrset = rrset_cache_lookup(
 323                 env->rrset_cache, dp->name, dp->namelen, LDNS_RR_TYPE_DS,
 324                 msg->qinfo.qclass, 0, now, 0);
 325         if(!rrset) {
 326                 /* NOTE: this won't work for alternate NSEC schemes
 327                  *      (opt-in, NSEC3) */
 328                 rrset = rrset_cache_lookup(env->rrset_cache, dp->name,
 329                         dp->namelen, LDNS_RR_TYPE_NSEC, msg->qinfo.qclass,
 330                         0, now, 0);
 331                 /* Note: the PACKED_RRSET_NSEC_AT_APEX flag is not used.
 332                  * since this is a referral, we need the NSEC at the parent
 333                  * side of the zone cut, not the NSEC at apex side. */
 334                 if(rrset && nsec_has_type(rrset, LDNS_RR_TYPE_DS)) {
 335                         lock_rw_unlock(&rrset->entry.lock);
 336                         rrset = NULL; /* discard wrong NSEC */
 337                 }
 338         }
 339         if(rrset) {
 340                 /* add it to auth section. This is the second rrset. */
 341                 if((msg->rep->rrsets[msg->rep->rrset_count] =
 342                         packed_rrset_copy_region(rrset, region, now))) {
 343                         msg->rep->ns_numrrsets++;
 344                         msg->rep->rrset_count++;
 345                 }
 346                 lock_rw_unlock(&rrset->entry.lock);
 347         }
 348 }
 349
 350 struct dns_msg*
 351 dns_msg_create(uint8_t* qname, size_t qnamelen, uint16_t qtype,
 352         uint16_t qclass, struct regional* region, size_t capacity)
 353 {
 354         struct dns_msg* msg = (struct dns_msg*)regional_alloc(region,
 355                 sizeof(struct dns_msg));
 356         if(!msg)
 357                 return NULL;
 358         msg->qinfo.qname = regional_alloc_init(region, qname, qnamelen);
 359         if(!msg->qinfo.qname)
 360                 return NULL;
 361         msg->qinfo.qname_len = qnamelen;
 362         msg->qinfo.qtype = qtype;
 363         msg->qinfo.qclass = qclass;
 364         /* non-packed reply_info, because it needs to grow the array */
 365         msg->rep = (struct reply_info*)regional_alloc_zero(region,
 366                 sizeof(struct reply_info)-sizeof(struct rrset_ref));
 367         if(!msg->rep)
 368                 return NULL;
 369         msg->rep->flags = BIT_QR; /* with QR, no AA */
 370         msg->rep->qdcount = 1;
 371         msg->rep->rrsets = (struct ub_packed_rrset_key**)
 372                 regional_alloc(region,
 373                 capacity*sizeof(struct ub_packed_rrset_key*));
 374         if(!msg->rep->rrsets)
 375                 return NULL;
 376         return msg;
 377 }
 378
 379 int
 380 dns_msg_authadd(struct dns_msg* msg, struct regional* region,
 381         struct ub_packed_rrset_key* rrset, time_t now)
 382 {
 383         if(!(msg->rep->rrsets[msg->rep->rrset_count++] =
 384                 packed_rrset_copy_region(rrset, region, now)))
 385                 return 0;
 386         msg->rep->ns_numrrsets++;
 387         return 1;
 388 }
 389
 390 struct delegpt*
 391 dns_cache_find_delegation(struct module_env* env, uint8_t* qname,
 392         size_t qnamelen, uint16_t qtype, uint16_t qclass,
 393         struct regional* region, struct dns_msg** msg, time_t now)
 394 {
 395         /* try to find closest NS rrset */
 396         struct ub_packed_rrset_key* nskey;
 397         struct packed_rrset_data* nsdata;
 398         struct delegpt* dp;
 399
 400         nskey = find_closest_of_type(env, qname, qnamelen, qclass, now,
 401                 LDNS_RR_TYPE_NS, 0);
 402         if(!nskey) /* hope the caller has hints to prime or something */
 403                 return NULL;
 404         nsdata = (struct packed_rrset_data*)nskey->entry.data;
 405         /* got the NS key, create delegation point */
 406         dp = delegpt_create(region);
 407         if(!dp || !delegpt_set_name(dp, region, nskey->rk.dname)) {
 408                 lock_rw_unlock(&nskey->entry.lock);
 409                 log_err("find_delegation: out of memory");
 410                 return NULL;
 411         }
 412         /* create referral message */
 413         if(msg) {
 414                 /* allocate the array to as much as we could need:
 415                  *      NS rrset + DS/NSEC rrset +
 416                  *      A rrset for every NS RR
 417                  *      AAAA rrset for every NS RR
 418                  */
 419                 *msg = dns_msg_create(qname, qnamelen, qtype, qclass, region,
 420                         2 + nsdata->count*2);
 421                 if(!*msg || !dns_msg_authadd(*msg, region, nskey, now)) {
 422                         lock_rw_unlock(&nskey->entry.lock);
 423                         log_err("find_delegation: out of memory");
 424                         return NULL;
 425                 }
 426         }
 427         if(!delegpt_rrset_add_ns(dp, region, nskey, 0))
 428                 log_err("find_delegation: addns out of memory");
 429         lock_rw_unlock(&nskey->entry.lock); /* first unlock before next lookup*/
 430         /* find and add DS/NSEC (if any) */
 431         if(msg)
 432                 find_add_ds(env, region, *msg, dp, now);
 433         /* find and add A entries */
 434         if(!find_add_addrs(env, qclass, region, dp, now, msg))
 435                 log_err("find_delegation: addrs out of memory");
 436         return dp;
 437 }
 438
 439 /** allocate dns_msg from query_info and reply_info */
 440 static struct dns_msg*
 441 gen_dns_msg(struct regional* region, struct query_info* q, size_t num)
 442 {
 443         struct dns_msg* msg = (struct dns_msg*)regional_alloc(region,
 444                 sizeof(struct dns_msg));
 445         if(!msg)
 446                 return NULL;
 447         memcpy(&msg->qinfo, q, sizeof(struct query_info));
 448         msg->qinfo.qname = regional_alloc_init(region, q->qname, q->qname_len);
 449         if(!msg->qinfo.qname)
 450                 return NULL;
 451         /* allocate replyinfo struct and rrset key array separately */
 452         msg->rep = (struct reply_info*)regional_alloc(region,
 453                 sizeof(struct reply_info) - sizeof(struct rrset_ref));
 454         if(!msg->rep)
 455                 return NULL;
 456         msg->rep->rrsets = (struct ub_packed_rrset_key**)
 457                 regional_alloc(region,
 458                 num * sizeof(struct ub_packed_rrset_key*));
 459         if(!msg->rep->rrsets)
 460                 return NULL;
 461         return msg;
 462 }
 463
 464 /** generate dns_msg from cached message */
 465 static struct dns_msg*
 466 tomsg(struct module_env* env, struct query_info* q, struct reply_info* r,
 467         struct regional* region, time_t now, struct regional* scratch)
 468 {
 469         struct dns_msg* msg;
 470         size_t i;
 471         if(now > r->ttl)
 472                 return NULL;
 473         msg = gen_dns_msg(region, q, r->rrset_count);
 474         if(!msg)
 475                 return NULL;
 476         msg->rep->flags = r->flags;
 477         msg->rep->qdcount = r->qdcount;
 478         msg->rep->ttl = r->ttl - now;
 479         if(r->prefetch_ttl > now)
 480                 msg->rep->prefetch_ttl = r->prefetch_ttl - now;
 481         else    msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 482         msg->rep->security = r->security;
 483         msg->rep->an_numrrsets = r->an_numrrsets;
 484         msg->rep->ns_numrrsets = r->ns_numrrsets;
 485         msg->rep->ar_numrrsets = r->ar_numrrsets;
 486         msg->rep->rrset_count = r->rrset_count;
 487         msg->rep->authoritative = r->authoritative;
 488         if(!rrset_array_lock(r->ref, r->rrset_count, now))
 489                 return NULL;
 490         if(r->an_numrrsets > 0 && (r->rrsets[0]->rk.type == htons(
 491                 LDNS_RR_TYPE_CNAME) || r->rrsets[0]->rk.type == htons(
 492                 LDNS_RR_TYPE_DNAME)) && !reply_check_cname_chain(r)) {
 493                 /* cname chain is now invalid, reconstruct msg */
 494                 rrset_array_unlock(r->ref, r->rrset_count);
 495                 return NULL;
 496         }
 497         if(r->security == sec_status_secure && !reply_all_rrsets_secure(r)) {
 498                 /* message rrsets have changed status, revalidate */
 499                 rrset_array_unlock(r->ref, r->rrset_count);
 500                 return NULL;
 501         }
 502         for(i=0; i<msg->rep->rrset_count; i++) {
 503                 msg->rep->rrsets[i] = packed_rrset_copy_region(r->rrsets[i],
 504                         region, now);
 505                 if(!msg->rep->rrsets[i]) {
 506                         rrset_array_unlock(r->ref, r->rrset_count);
 507                         return NULL;
 508                 }
 509         }
 510         rrset_array_unlock_touch(env->rrset_cache, scratch, r->ref,
 511                 r->rrset_count);
 512         return msg;
 513 }
 514
 515 /** synthesize RRset-only response from cached RRset item */
 516 static struct dns_msg*
 517 rrset_msg(struct ub_packed_rrset_key* rrset, struct regional* region,
 518         time_t now, struct query_info* q)
 519 {
 520         struct dns_msg* msg;
 521         struct packed_rrset_data* d = (struct packed_rrset_data*)
 522                 rrset->entry.data;
 523         if(now > d->ttl)
 524                 return NULL;
 525         msg = gen_dns_msg(region, q, 1); /* only the CNAME (or other) RRset */
 526         if(!msg)
 527                 return NULL;
 528         msg->rep->flags = BIT_QR; /* reply, no AA, no error */
 529         msg->rep->authoritative = 0; /* reply stored in cache can't be authoritative */
 530         msg->rep->qdcount = 1;
 531         msg->rep->ttl = d->ttl - now;
 532         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 533         msg->rep->security = sec_status_unchecked;
 534         msg->rep->an_numrrsets = 1;
 535         msg->rep->ns_numrrsets = 0;
 536         msg->rep->ar_numrrsets = 0;
 537         msg->rep->rrset_count = 1;
 538         msg->rep->rrsets[0] = packed_rrset_copy_region(rrset, region, now);
 539         if(!msg->rep->rrsets[0]) /* copy CNAME */
 540                 return NULL;
 541         return msg;
 542 }
 543
 544 /** synthesize DNAME+CNAME response from cached DNAME item */
 545 static struct dns_msg*
 546 synth_dname_msg(struct ub_packed_rrset_key* rrset, struct regional* region,
 547         time_t now, struct query_info* q)
 548 {
 549         struct dns_msg* msg;
 550         struct ub_packed_rrset_key* ck;
 551         struct packed_rrset_data* newd, *d = (struct packed_rrset_data*)
 552                 rrset->entry.data;
 553         uint8_t* newname, *dtarg = NULL;
 554         size_t newlen, dtarglen;
 555         if(now > d->ttl)
 556                 return NULL;
 557         /* only allow validated (with DNSSEC) DNAMEs used from cache
 558          * for insecure DNAMEs, query again. */
 559         if(d->security != sec_status_secure)
 560                 return NULL;
 561         msg = gen_dns_msg(region, q, 2); /* DNAME + CNAME RRset */
 562         if(!msg)
 563                 return NULL;
 564         msg->rep->flags = BIT_QR; /* reply, no AA, no error */
 565         msg->rep->authoritative = 0; /* reply stored in cache can't be authoritative */
 566         msg->rep->qdcount = 1;
 567         msg->rep->ttl = d->ttl - now;
 568         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 569         msg->rep->security = sec_status_unchecked;
 570         msg->rep->an_numrrsets = 1;
 571         msg->rep->ns_numrrsets = 0;
 572         msg->rep->ar_numrrsets = 0;
 573         msg->rep->rrset_count = 1;
 574         msg->rep->rrsets[0] = packed_rrset_copy_region(rrset, region, now);
 575         if(!msg->rep->rrsets[0]) /* copy DNAME */
 576                 return NULL;
 577         /* synth CNAME rrset */
 578         get_cname_target(rrset, &dtarg, &dtarglen);
 579         if(!dtarg)
 580                 return NULL;
 581         newlen = q->qname_len + dtarglen - rrset->rk.dname_len;
 582         if(newlen > LDNS_MAX_DOMAINLEN) {
 583                 msg->rep->flags |= LDNS_RCODE_YXDOMAIN;
 584                 return msg;
 585         }
 586         newname = (uint8_t*)regional_alloc(region, newlen);
 587         if(!newname)
 588                 return NULL;
 589         /* new name is concatenation of qname front (without DNAME owner)
 590          * and DNAME target name */
 591         memcpy(newname, q->qname, q->qname_len-rrset->rk.dname_len);
 592         memmove(newname+(q->qname_len-rrset->rk.dname_len), dtarg, dtarglen);
 593         /* create rest of CNAME rrset */
 594         ck = (struct ub_packed_rrset_key*)regional_alloc(region,
 595                 sizeof(struct ub_packed_rrset_key));
 596         if(!ck)
 597                 return NULL;
 598         memset(&ck->entry, 0, sizeof(ck->entry));
 599         msg->rep->rrsets[1] = ck;
 600         ck->entry.key = ck;
 601         ck->rk.type = htons(LDNS_RR_TYPE_CNAME);
 602         ck->rk.rrset_class = rrset->rk.rrset_class;
 603         ck->rk.flags = 0;
 604         ck->rk.dname = regional_alloc_init(region, q->qname, q->qname_len);
 605         if(!ck->rk.dname)
 606                 return NULL;
 607         ck->rk.dname_len = q->qname_len;
 608         ck->entry.hash = rrset_key_hash(&ck->rk);
 609         newd = (struct packed_rrset_data*)regional_alloc_zero(region,
 610                 sizeof(struct packed_rrset_data) + sizeof(size_t) +
 611                 sizeof(uint8_t*) + sizeof(time_t) + sizeof(uint16_t)
 612                 + newlen);
 613         if(!newd)
 614                 return NULL;
 615         ck->entry.data = newd;
 616         newd->ttl = 0; /* 0 for synthesized CNAME TTL */
 617         newd->count = 1;
 618         newd->rrsig_count = 0;
 619         newd->trust = rrset_trust_ans_noAA;
 620         newd->rr_len = (size_t*)((uint8_t*)newd +
 621                 sizeof(struct packed_rrset_data));
 622         newd->rr_len[0] = newlen + sizeof(uint16_t);
 623         packed_rrset_ptr_fixup(newd);
 624         newd->rr_ttl[0] = newd->ttl;
 625         msg->rep->ttl = newd->ttl;
 626         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(newd->ttl);
 627         sldns_write_uint16(newd->rr_data[0], newlen);
 628         memmove(newd->rr_data[0] + sizeof(uint16_t), newname, newlen);
 629         msg->rep->an_numrrsets ++;
 630         msg->rep->rrset_count ++;
 631         return msg;
 632 }
 633
 634 struct dns_msg*
 635 dns_cache_lookup(struct module_env* env,
 636         uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
 637         uint16_t flags, struct regional* region, struct regional* scratch)
 638 {
 639         struct lruhash_entry* e;
 640         struct query_info k;
 641         hashvalue_t h;
 642         time_t now = *env->now;
 643         struct ub_packed_rrset_key* rrset;
 644
 645         /* lookup first, this has both NXdomains and ANSWER responses */
 646         k.qname = qname;
 647         k.qname_len = qnamelen;
 648         k.qtype = qtype;
 649         k.qclass = qclass;
 650         h = query_info_hash(&k, flags);
 651         e = slabhash_lookup(env->msg_cache, h, &k, 0);
 652         if(e) {
 653                 struct msgreply_entry* key = (struct msgreply_entry*)e->key;
 654                 struct reply_info* data = (struct reply_info*)e->data;
 655                 struct dns_msg* msg = tomsg(env, &key->key, data, region, now,
 656                         scratch);
 657                 if(msg) {
 658                         lock_rw_unlock(&e->lock);
 659                         return msg;
 660                 }
 661                 /* could be msg==NULL; due to TTL or not all rrsets available */
 662                 lock_rw_unlock(&e->lock);
 663         }
 664
 665         /* see if a DNAME exists. Checked for first, to enforce that DNAMEs
 666          * are more important, the CNAME is resynthesized and thus
 667          * consistent with the DNAME */
 668         if( (rrset=find_closest_of_type(env, qname, qnamelen, qclass, now,
 669                 LDNS_RR_TYPE_DNAME, 1))) {
 670                 /* synthesize a DNAME+CNAME message based on this */
 671                 struct dns_msg* msg = synth_dname_msg(rrset, region, now, &k);
 672                 if(msg) {
 673                         lock_rw_unlock(&rrset->entry.lock);
 674                         return msg;
 675                 }
 676                 lock_rw_unlock(&rrset->entry.lock);
 677         }
 678
 679         /* see if we have CNAME for this domain,
 680          * but not for DS records (which are part of the parent) */
 681         if( qtype != LDNS_RR_TYPE_DS &&
 682            (rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen,
 683                 LDNS_RR_TYPE_CNAME, qclass, 0, now, 0))) {
 684                 struct dns_msg* msg = rrset_msg(rrset, region, now, &k);
 685                 if(msg) {
 686                         lock_rw_unlock(&rrset->entry.lock);
 687                         return msg;
 688                 }
 689                 lock_rw_unlock(&rrset->entry.lock);
 690         }
 691
 692         /* construct DS, DNSKEY, DLV messages from rrset cache. */
 693         if((qtype == LDNS_RR_TYPE_DS || qtype == LDNS_RR_TYPE_DNSKEY ||
 694                 qtype == LDNS_RR_TYPE_DLV) &&
 695                 (rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen,
 696                 qtype, qclass, 0, now, 0))) {
 697                 /* if the rrset is from the additional section, and the
 698                  * signatures have fallen off, then do not synthesize a msg
 699                  * instead, allow a full query for signed results to happen.
 700                  * Forego all rrset data from additional section, because
 701                  * some signatures may not be present and cause validation
 702                  * failure.
 703                  */
 704                 struct packed_rrset_data *d = (struct packed_rrset_data*)
 705                         rrset->entry.data;
 706                 if(d->trust != rrset_trust_add_noAA &&
 707                         d->trust != rrset_trust_add_AA &&
 708                         (qtype == LDNS_RR_TYPE_DS ||
 709                                 (d->trust != rrset_trust_auth_noAA
 710                                 && d->trust != rrset_trust_auth_AA) )) {
 711                         struct dns_msg* msg = rrset_msg(rrset, region, now, &k);
 712                         if(msg) {
 713                                 lock_rw_unlock(&rrset->entry.lock);
 714                                 return msg;
 715                         }
 716                 }
 717                 lock_rw_unlock(&rrset->entry.lock);
 718         }
 719
 720         /* stop downwards cache search on NXDOMAIN.
 721          * Empty nonterminals are NOERROR, so an NXDOMAIN for foo
 722          * means bla.foo also does not exist.  The DNSSEC proofs are
 723          * the same.  We search upwards for NXDOMAINs. */
 724         if(env->cfg->harden_below_nxdomain)
 725             while(!dname_is_root(k.qname)) {
 726                 dname_remove_label(&k.qname, &k.qname_len);
 727                 h = query_info_hash(&k, flags);
 728                 e = slabhash_lookup(env->msg_cache, h, &k, 0);
 729                 if(e) {
 730                         struct reply_info* data = (struct reply_info*)e->data;
 731                         struct dns_msg* msg;
 732                         if(FLAGS_GET_RCODE(data->flags) == LDNS_RCODE_NXDOMAIN
 733                           && data->security == sec_status_secure
 734                           && (msg=tomsg(env, &k, data, region, now, scratch))){
 735                                 lock_rw_unlock(&e->lock);
 736                                 msg->qinfo.qname=qname;
 737                                 msg->qinfo.qname_len=qnamelen;
 738                                 /* check that DNSSEC really works out */
 739                                 msg->rep->security = sec_status_unchecked;
 740                                 return msg;
 741                         }
 742                         lock_rw_unlock(&e->lock);
 743                 }
 744         }
 745
 746         return NULL;
 747 }
 748
 749 int
 750 dns_cache_store(struct module_env* env, struct query_info* msgqinf,
 751         struct reply_info* msgrep, int is_referral, time_t leeway, int pside,
 752         struct regional* region, uint16_t flags)
 753 {
 754         struct reply_info* rep = NULL;
 755         /* alloc, malloc properly (not in region, like msg is) */
 756         rep = reply_info_copy(msgrep, env->alloc, NULL);
 757         if(!rep)
 758                 return 0;
 759         /* ttl must be relative ;i.e. 0..86400 not  time(0)+86400.
 760          * the env->now is added to message and RRsets in this routine. */
 761         /* the leeway is used to invalidate other rrsets earlier */
 762
 763         if(is_referral) {
 764                 /* store rrsets */
 765                 struct rrset_ref ref;
 766                 size_t i;
 767                 for(i=0; i<rep->rrset_count; i++) {
 768                         packed_rrset_ttl_add((struct packed_rrset_data*)
 769                                 rep->rrsets[i]->entry.data, *env->now);
 770                         ref.key = rep->rrsets[i];
 771                         ref.id = rep->rrsets[i]->id;
 772                         /*ignore ret: it was in the cache, ref updated */
 773                         /* no leeway for typeNS */
 774                         (void)rrset_cache_update(env->rrset_cache, &ref,
 775                                 env->alloc, *env->now +
 776                                 ((ntohs(ref.key->rk.type)==LDNS_RR_TYPE_NS
 777                                  && !pside) ? 0:leeway));
 778                 }
 779                 free(rep);
 780                 return 1;
 781         } else {
 782                 /* store msg, and rrsets */
 783                 struct query_info qinf;
 784                 hashvalue_t h;
 785
 786                 qinf = *msgqinf;
 787                 qinf.qname = memdup(msgqinf->qname, msgqinf->qname_len);
 788                 if(!qinf.qname) {
 789                         reply_info_parsedelete(rep, env->alloc);
 790                         return 0;
 791                 }
 792                 /* fixup flags to be sensible for a reply based on the cache */
 793                 /* this module means that RA is available. It is an answer QR.
 794                  * Not AA from cache. Not CD in cache (depends on client bit). */
 795                 rep->flags |= (BIT_RA | BIT_QR);
 796                 rep->flags &= ~(BIT_AA | BIT_CD);
 797                 h = query_info_hash(&qinf, flags);
 798                 dns_cache_store_msg(env, &qinf, h, rep, leeway, pside, msgrep,
 799                         region);
 800                 /* qname is used inside query_info_entrysetup, and set to
 801                  * NULL. If it has not been used, free it. free(0) is safe. */
 802                 free(qinf.qname);
 803         }
 804         return 1;
 805 }
 806
 807 int
 808 dns_cache_prefetch_adjust(struct module_env* env, struct query_info* qinfo,
 809         time_t adjust, uint16_t flags)
 810 {
 811         struct msgreply_entry* msg;
 812         msg = msg_cache_lookup(env, qinfo->qname, qinfo->qname_len,
 813                 qinfo->qtype, qinfo->qclass, flags, *env->now, 1);
 814         if(msg) {
 815                 struct reply_info* rep = (struct reply_info*)msg->entry.data;
 816                 if(rep) {
 817                         rep->prefetch_ttl += adjust;
 818                         lock_rw_unlock(&msg->entry.lock);
 819                         return 1;
 820                 }
 821                 lock_rw_unlock(&msg->entry.lock);
 822         }
 823         return 0;
 824 }