contrib/unbound/cachedb/cachedb.c

   1 /*
   2  * cachedb/cachedb.c - cache from a database external to the program module
   3  *
   4  * Copyright (c) 2016, NLnet Labs. All rights reserved.
   5  *
   6  * This software is open source.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * Redistributions of source code must retain the above copyright notice,
  13  * this list of conditions and the following disclaimer.
  14  *
  15  * Redistributions in binary form must reproduce the above copyright notice,
  16  * this list of conditions and the following disclaimer in the documentation
  17  * and/or other materials provided with the distribution.
  18  *
  19  * Neither the name of the NLNET LABS nor the names of its contributors may
  20  * be used to endorse or promote products derived from this software without
  21  * specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 /**
  37  * \file
  38  *
  39  * This file contains a module that uses an external database to cache
  40  * dns responses.
  41  */
  42
  43 #include "config.h"
  44 #ifdef USE_CACHEDB
  45 #include "cachedb/cachedb.h"
  46 #include "cachedb/redis.h"
  47 #include "util/regional.h"
  48 #include "util/net_help.h"
  49 #include "util/config_file.h"
  50 #include "util/data/msgreply.h"
  51 #include "util/data/msgencode.h"
  52 #include "services/cache/dns.h"
  53 #include "validator/val_neg.h"
  54 #include "validator/val_secalgo.h"
  55 #include "iterator/iter_utils.h"
  56 #include "sldns/parseutil.h"
  57 #include "sldns/wire2str.h"
  58 #include "sldns/sbuffer.h"
  59
  60 /* header file for htobe64 */
  61 #ifdef HAVE_ENDIAN_H
  62 #  include <endian.h>
  63 #endif
  64 #ifdef HAVE_SYS_ENDIAN_H
  65 #  include <sys/endian.h>
  66 #endif
  67 #ifdef HAVE_LIBKERN_OSBYTEORDER_H
  68 /* In practice this is specific to MacOS X.  We assume it doesn't have
  69 * htobe64/be64toh but has alternatives with a different name. */
  70 #  include <libkern/OSByteOrder.h>
  71 #  define htobe64(x) OSSwapHostToBigInt64(x)
  72 #  define be64toh(x) OSSwapBigToHostInt64(x)
  73 #endif
  74
  75 /** the unit test testframe for cachedb, its module state contains
  76  * a cache for a couple queries (in memory). */
  77 struct testframe_moddata {
  78         /** lock for mutex */
  79         lock_basic_type lock;
  80         /** key for single stored data element, NULL if none */
  81         char* stored_key;
  82         /** data for single stored data element, NULL if none */
  83         uint8_t* stored_data;
  84         /** length of stored data */
  85         size_t stored_datalen;
  86 };
  87
  88 static int
  89 testframe_init(struct module_env* env, struct cachedb_env* cachedb_env)
  90 {
  91         struct testframe_moddata* d;
  92         (void)env;
  93         verbose(VERB_ALGO, "testframe_init");
  94         d = (struct testframe_moddata*)calloc(1,
  95                 sizeof(struct testframe_moddata));
  96         cachedb_env->backend_data = (void*)d;
  97         if(!cachedb_env->backend_data) {
  98                 log_err("out of memory");
  99                 return 0;
 100         }
 101         lock_basic_init(&d->lock);
 102         lock_protect(&d->lock, d, sizeof(*d));
 103         return 1;
 104 }
 105
 106 static void
 107 testframe_deinit(struct module_env* env, struct cachedb_env* cachedb_env)
 108 {
 109         struct testframe_moddata* d = (struct testframe_moddata*)
 110                 cachedb_env->backend_data;
 111         (void)env;
 112         verbose(VERB_ALGO, "testframe_deinit");
 113         if(!d)
 114                 return;
 115         lock_basic_destroy(&d->lock);
 116         free(d->stored_key);
 117         free(d->stored_data);
 118         free(d);
 119 }
 120
 121 static int
 122 testframe_lookup(struct module_env* env, struct cachedb_env* cachedb_env,
 123         char* key, struct sldns_buffer* result_buffer)
 124 {
 125         struct testframe_moddata* d = (struct testframe_moddata*)
 126                 cachedb_env->backend_data;
 127         (void)env;
 128         verbose(VERB_ALGO, "testframe_lookup of %s", key);
 129         lock_basic_lock(&d->lock);
 130         if(d->stored_key && strcmp(d->stored_key, key) == 0) {
 131                 if(d->stored_datalen > sldns_buffer_capacity(result_buffer)) {
 132                         lock_basic_unlock(&d->lock);
 133                         return 0; /* too large */
 134                 }
 135                 verbose(VERB_ALGO, "testframe_lookup found %d bytes",
 136                         (int)d->stored_datalen);
 137                 sldns_buffer_clear(result_buffer);
 138                 sldns_buffer_write(result_buffer, d->stored_data,
 139                         d->stored_datalen);
 140                 sldns_buffer_flip(result_buffer);
 141                 lock_basic_unlock(&d->lock);
 142                 return 1;
 143         }
 144         lock_basic_unlock(&d->lock);
 145         return 0;
 146 }
 147
 148 static void
 149 testframe_store(struct module_env* env, struct cachedb_env* cachedb_env,
 150         char* key, uint8_t* data, size_t data_len)
 151 {
 152         struct testframe_moddata* d = (struct testframe_moddata*)
 153                 cachedb_env->backend_data;
 154         (void)env;
 155         lock_basic_lock(&d->lock);
 156         verbose(VERB_ALGO, "testframe_store %s (%d bytes)", key, (int)data_len);
 157
 158         /* free old data element (if any) */
 159         free(d->stored_key);
 160         d->stored_key = NULL;
 161         free(d->stored_data);
 162         d->stored_data = NULL;
 163         d->stored_datalen = 0;
 164
 165         d->stored_data = memdup(data, data_len);
 166         if(!d->stored_data) {
 167                 lock_basic_unlock(&d->lock);
 168                 log_err("out of memory");
 169                 return;
 170         }
 171         d->stored_datalen = data_len;
 172         d->stored_key = strdup(key);
 173         if(!d->stored_key) {
 174                 free(d->stored_data);
 175                 d->stored_data = NULL;
 176                 d->stored_datalen = 0;
 177                 lock_basic_unlock(&d->lock);
 178                 return;
 179         }
 180         lock_basic_unlock(&d->lock);
 181         /* (key,data) successfully stored */
 182 }
 183
 184 /** The testframe backend is for unit tests */
 185 static struct cachedb_backend testframe_backend = { "testframe",
 186         testframe_init, testframe_deinit, testframe_lookup, testframe_store
 187 };
 188
 189 /** find a particular backend from possible backends */
 190 static struct cachedb_backend*
 191 cachedb_find_backend(const char* str)
 192 {
 193 #ifdef USE_REDIS
 194         if(strcmp(str, redis_backend.name) == 0)
 195                 return &redis_backend;
 196 #endif
 197         if(strcmp(str, testframe_backend.name) == 0)
 198                 return &testframe_backend;
 199         /* TODO add more backends here */
 200         return NULL;
 201 }
 202
 203 /** apply configuration to cachedb module 'global' state */
 204 static int
 205 cachedb_apply_cfg(struct cachedb_env* cachedb_env, struct config_file* cfg)
 206 {
 207         const char* backend_str = cfg->cachedb_backend;
 208
 209         /* If unspecified we use the in-memory test DB. */
 210         if(!backend_str)
 211                 backend_str = "testframe";
 212         cachedb_env->backend = cachedb_find_backend(backend_str);
 213         if(!cachedb_env->backend) {
 214                 log_err("cachedb: cannot find backend name '%s'", backend_str);
 215                 return 0;
 216         }
 217
 218         /* TODO see if more configuration needs to be applied or not */
 219         return 1;
 220 }
 221
 222 int
 223 cachedb_init(struct module_env* env, int id)
 224 {
 225         struct cachedb_env* cachedb_env = (struct cachedb_env*)calloc(1,
 226                 sizeof(struct cachedb_env));
 227         if(!cachedb_env) {
 228                 log_err("malloc failure");
 229                 return 0;
 230         }
 231         env->modinfo[id] = (void*)cachedb_env;
 232         if(!cachedb_apply_cfg(cachedb_env, env->cfg)) {
 233                 log_err("cachedb: could not apply configuration settings.");
 234                 return 0;
 235         }
 236         /* see if a backend is selected */
 237         if(!cachedb_env->backend || !cachedb_env->backend->name)
 238                 return 1;
 239         if(!(*cachedb_env->backend->init)(env, cachedb_env)) {
 240                 log_err("cachedb: could not init %s backend",
 241                         cachedb_env->backend->name);
 242                 return 0;
 243         }
 244         cachedb_env->enabled = 1;
 245         return 1;
 246 }
 247
 248 void
 249 cachedb_deinit(struct module_env* env, int id)
 250 {
 251         struct cachedb_env* cachedb_env;
 252         if(!env || !env->modinfo[id])
 253                 return;
 254         cachedb_env = (struct cachedb_env*)env->modinfo[id];
 255         /* free contents */
 256         /* TODO */
 257         if(cachedb_env->enabled) {
 258                 (*cachedb_env->backend->deinit)(env, cachedb_env);
 259         }
 260
 261         free(cachedb_env);
 262         env->modinfo[id] = NULL;
 263 }
 264
 265 /** new query for cachedb */
 266 static int
 267 cachedb_new(struct module_qstate* qstate, int id)
 268 {
 269         struct cachedb_qstate* iq = (struct cachedb_qstate*)regional_alloc(
 270                 qstate->region, sizeof(struct cachedb_qstate));
 271         qstate->minfo[id] = iq;
 272         if(!iq)
 273                 return 0;
 274         memset(iq, 0, sizeof(*iq));
 275         /* initialise it */
 276         /* TODO */
 277
 278         return 1;
 279 }
 280
 281 /**
 282  * Return an error
 283  * @param qstate: our query state
 284  * @param id: module id
 285  * @param rcode: error code (DNS errcode).
 286  * @return: 0 for use by caller, to make notation easy, like:
 287  *      return error_response(..).
 288  */
 289 static int
 290 error_response(struct module_qstate* qstate, int id, int rcode)
 291 {
 292         verbose(VERB_QUERY, "return error response %s",
 293                 sldns_lookup_by_id(sldns_rcodes, rcode)?
 294                 sldns_lookup_by_id(sldns_rcodes, rcode)->name:"??");
 295         qstate->return_rcode = rcode;
 296         qstate->return_msg = NULL;
 297         qstate->ext_state[id] = module_finished;
 298         return 0;
 299 }
 300
 301 /**
 302  * Hash the query name, type, class and dbacess-secret into lookup buffer.
 303  * @param qstate: query state with query info
 304  *      and env->cfg with secret.
 305  * @param buf: returned buffer with hash to lookup
 306  * @param len: length of the buffer.
 307  */
 308 static void
 309 calc_hash(struct module_qstate* qstate, char* buf, size_t len)
 310 {
 311         uint8_t clear[1024];
 312         size_t clen = 0;
 313         uint8_t hash[CACHEDB_HASHSIZE/8];
 314         const char* hex = "0123456789ABCDEF";
 315         const char* secret = qstate->env->cfg->cachedb_secret ?
 316                 qstate->env->cfg->cachedb_secret : "default";
 317         size_t i;
 318
 319         /* copy the hash info into the clear buffer */
 320         if(clen + qstate->qinfo.qname_len < sizeof(clear)) {
 321                 memmove(clear+clen, qstate->qinfo.qname,
 322                         qstate->qinfo.qname_len);
 323                 clen += qstate->qinfo.qname_len;
 324         }
 325         if(clen + 4 < sizeof(clear)) {
 326                 uint16_t t = htons(qstate->qinfo.qtype);
 327                 uint16_t c = htons(qstate->qinfo.qclass);
 328                 memmove(clear+clen, &t, 2);
 329                 memmove(clear+clen+2, &c, 2);
 330                 clen += 4;
 331         }
 332         if(secret && secret[0] && clen + strlen(secret) < sizeof(clear)) {
 333                 memmove(clear+clen, secret, strlen(secret));
 334                 clen += strlen(secret);
 335         }
 336
 337         /* hash the buffer */
 338         secalgo_hash_sha256(clear, clen, hash);
 339         memset(clear, 0, clen);
 340
 341         /* hex encode output for portability (some online dbs need
 342          * no nulls, no control characters, and so on) */
 343         log_assert(len >= sizeof(hash)*2 + 1);
 344         (void)len;
 345         for(i=0; i<sizeof(hash); i++) {
 346                 buf[i*2] = hex[(hash[i]&0xf0)>>4];
 347                 buf[i*2+1] = hex[hash[i]&0x0f];
 348         }
 349         buf[sizeof(hash)*2] = 0;
 350 }
 351
 352 /** convert data from return_msg into the data buffer */
 353 static int
 354 prep_data(struct module_qstate* qstate, struct sldns_buffer* buf)
 355 {
 356         uint64_t timestamp, expiry;
 357         size_t oldlim;
 358         struct edns_data edns;
 359         memset(&edns, 0, sizeof(edns));
 360         edns.edns_present = 1;
 361         edns.bits = EDNS_DO;
 362         edns.ext_rcode = 0;
 363         edns.edns_version = EDNS_ADVERTISED_VERSION;
 364         edns.udp_size = EDNS_ADVERTISED_SIZE;
 365
 366         if(!qstate->return_msg || !qstate->return_msg->rep)
 367                 return 0;
 368         /* We don't store the reply if its TTL is 0 unless serve-expired is
 369          * enabled.  Such a reply won't be reusable and simply be a waste for
 370          * the backend.  It's also compatible with the default behavior of
 371          * dns_cache_store_msg(). */
 372         if(qstate->return_msg->rep->ttl == 0 &&
 373                 !qstate->env->cfg->serve_expired)
 374                 return 0;
 375         if(verbosity >= VERB_ALGO)
 376                 log_dns_msg("cachedb encoding", &qstate->return_msg->qinfo,
 377                         qstate->return_msg->rep);
 378         if(!reply_info_answer_encode(&qstate->return_msg->qinfo,
 379                 qstate->return_msg->rep, 0, qstate->query_flags,
 380                 buf, 0, 1, qstate->env->scratch, 65535, &edns, 1, 0))
 381                 return 0;
 382
 383         /* TTLs in the return_msg are relative to time(0) so we have to
 384          * store that, we also store the smallest ttl in the packet+time(0)
 385          * as the packet expiry time */
 386         /* qstate->return_msg->rep->ttl contains that relative shortest ttl */
 387         timestamp = (uint64_t)*qstate->env->now;
 388         expiry = timestamp + (uint64_t)qstate->return_msg->rep->ttl;
 389         timestamp = htobe64(timestamp);
 390         expiry = htobe64(expiry);
 391         oldlim = sldns_buffer_limit(buf);
 392         if(oldlim + sizeof(timestamp)+sizeof(expiry) >=
 393                 sldns_buffer_capacity(buf))
 394                 return 0; /* doesn't fit. */
 395         sldns_buffer_set_limit(buf, oldlim + sizeof(timestamp)+sizeof(expiry));
 396         sldns_buffer_write_at(buf, oldlim, &timestamp, sizeof(timestamp));
 397         sldns_buffer_write_at(buf, oldlim+sizeof(timestamp), &expiry,
 398                 sizeof(expiry));
 399
 400         return 1;
 401 }
 402
 403 /** check expiry, return true if matches OK */
 404 static int
 405 good_expiry_and_qinfo(struct module_qstate* qstate, struct sldns_buffer* buf)
 406 {
 407         uint64_t expiry;
 408         /* the expiry time is the last bytes of the buffer */
 409         if(sldns_buffer_limit(buf) < sizeof(expiry))
 410                 return 0;
 411         sldns_buffer_read_at(buf, sldns_buffer_limit(buf)-sizeof(expiry),
 412                 &expiry, sizeof(expiry));
 413         expiry = be64toh(expiry);
 414
 415         if((time_t)expiry < *qstate->env->now &&
 416                 !qstate->env->cfg->serve_expired)
 417                 return 0;
 418
 419         return 1;
 420 }
 421
 422 /* Adjust the TTL of the given RRset by 'subtract'.  If 'subtract' is
 423  * negative, set the TTL to 0. */
 424 static void
 425 packed_rrset_ttl_subtract(struct packed_rrset_data* data, time_t subtract)
 426 {
 427         size_t i;
 428         size_t total = data->count + data->rrsig_count;
 429         if(subtract >= 0 && data->ttl > subtract)
 430                 data->ttl -= subtract;
 431         else    data->ttl = 0;
 432         for(i=0; i<total; i++) {
 433                 if(subtract >= 0 && data->rr_ttl[i] > subtract)
 434                         data->rr_ttl[i] -= subtract;
 435                 else    data->rr_ttl[i] = 0;
 436         }
 437 }
 438
 439 /* Adjust the TTL of a DNS message and its RRs by 'adjust'.  If 'adjust' is
 440  * negative, set the TTLs to 0. */
 441 static void
 442 adjust_msg_ttl(struct dns_msg* msg, time_t adjust)
 443 {
 444         size_t i;
 445         if(adjust >= 0 && msg->rep->ttl > adjust)
 446                 msg->rep->ttl -= adjust;
 447         else    msg->rep->ttl = 0;
 448         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 449
 450         for(i=0; i<msg->rep->rrset_count; i++) {
 451                 packed_rrset_ttl_subtract((struct packed_rrset_data*)msg->
 452                         rep->rrsets[i]->entry.data, adjust);
 453         }
 454 }
 455
 456 /** convert dns message in buffer to return_msg */
 457 static int
 458 parse_data(struct module_qstate* qstate, struct sldns_buffer* buf)
 459 {
 460         struct msg_parse* prs;
 461         struct edns_data edns;
 462         uint64_t timestamp, expiry;
 463         time_t adjust;
 464         size_t lim = sldns_buffer_limit(buf);
 465         if(lim < LDNS_HEADER_SIZE+sizeof(timestamp)+sizeof(expiry))
 466                 return 0; /* too short */
 467
 468         /* remove timestamp and expiry from end */
 469         sldns_buffer_read_at(buf, lim-sizeof(expiry), &expiry, sizeof(expiry));
 470         sldns_buffer_read_at(buf, lim-sizeof(expiry)-sizeof(timestamp),
 471                 &timestamp, sizeof(timestamp));
 472         expiry = be64toh(expiry);
 473         timestamp = be64toh(timestamp);
 474
 475         /* parse DNS packet */
 476         regional_free_all(qstate->env->scratch);
 477         prs = (struct msg_parse*)regional_alloc(qstate->env->scratch,
 478                 sizeof(struct msg_parse));
 479         if(!prs)
 480                 return 0; /* out of memory */
 481         memset(prs, 0, sizeof(*prs));
 482         memset(&edns, 0, sizeof(edns));
 483         sldns_buffer_set_limit(buf, lim - sizeof(expiry)-sizeof(timestamp));
 484         if(parse_packet(buf, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) {
 485                 sldns_buffer_set_limit(buf, lim);
 486                 return 0;
 487         }
 488         if(parse_extract_edns(prs, &edns, qstate->env->scratch) !=
 489                 LDNS_RCODE_NOERROR) {
 490                 sldns_buffer_set_limit(buf, lim);
 491                 return 0;
 492         }
 493
 494         qstate->return_msg = dns_alloc_msg(buf, prs, qstate->region);
 495         sldns_buffer_set_limit(buf, lim);
 496         if(!qstate->return_msg)
 497                 return 0;
 498
 499         qstate->return_rcode = LDNS_RCODE_NOERROR;
 500
 501         /* see how much of the TTL expired, and remove it */
 502         if(*qstate->env->now <= (time_t)timestamp) {
 503                 verbose(VERB_ALGO, "cachedb msg adjust by zero");
 504                 return 1; /* message from the future (clock skew?) */
 505         }
 506         adjust = *qstate->env->now - (time_t)timestamp;
 507         if(qstate->return_msg->rep->ttl < adjust) {
 508                 verbose(VERB_ALGO, "cachedb msg expired");
 509                 /* If serve-expired is enabled, we still use an expired message
 510                  * setting the TTL to 0. */
 511                 if(qstate->env->cfg->serve_expired)
 512                         adjust = -1;
 513                 else
 514                         return 0; /* message expired */
 515         }
 516         verbose(VERB_ALGO, "cachedb msg adjusted down by %d", (int)adjust);
 517         adjust_msg_ttl(qstate->return_msg, adjust);
 518
 519         /* Similar to the unbound worker, if serve-expired is enabled and
 520          * the msg would be considered to be expired, mark the state so a
 521          * refetch will be scheduled.  The comparison between 'expiry' and
 522          * 'now' should be redundant given how these values were calculated,
 523          * but we check it just in case as does good_expiry_and_qinfo(). */
 524         if(qstate->env->cfg->serve_expired &&
 525                 (adjust == -1 || (time_t)expiry < *qstate->env->now)) {
 526                 qstate->need_refetch = 1;
 527         }
 528
 529         return 1;
 530 }
 531
 532 /**
 533  * Lookup the qstate.qinfo in extcache, store in qstate.return_msg.
 534  * return true if lookup was successful.
 535  */
 536 static int
 537 cachedb_extcache_lookup(struct module_qstate* qstate, struct cachedb_env* ie)
 538 {
 539         char key[(CACHEDB_HASHSIZE/8)*2+1];
 540         calc_hash(qstate, key, sizeof(key));
 541
 542         /* call backend to fetch data for key into scratch buffer */
 543         if( !(*ie->backend->lookup)(qstate->env, ie, key,
 544                 qstate->env->scratch_buffer)) {
 545                 return 0;
 546         }
 547
 548         /* check expiry date and check if query-data matches */
 549         if( !good_expiry_and_qinfo(qstate, qstate->env->scratch_buffer) ) {
 550                 return 0;
 551         }
 552
 553         /* parse dns message into return_msg */
 554         if( !parse_data(qstate, qstate->env->scratch_buffer) ) {
 555                 return 0;
 556         }
 557         return 1;
 558 }
 559
 560 /**
 561  * Store the qstate.return_msg in extcache for key qstate.info
 562  */
 563 static void
 564 cachedb_extcache_store(struct module_qstate* qstate, struct cachedb_env* ie)
 565 {
 566         char key[(CACHEDB_HASHSIZE/8)*2+1];
 567         calc_hash(qstate, key, sizeof(key));
 568
 569         /* prepare data in scratch buffer */
 570         if(!prep_data(qstate, qstate->env->scratch_buffer))
 571                 return;
 572
 573         /* call backend */
 574         (*ie->backend->store)(qstate->env, ie, key,
 575                 sldns_buffer_begin(qstate->env->scratch_buffer),
 576                 sldns_buffer_limit(qstate->env->scratch_buffer));
 577 }
 578
 579 /**
 580  * See if unbound's internal cache can answer the query
 581  */
 582 static int
 583 cachedb_intcache_lookup(struct module_qstate* qstate)
 584 {
 585         struct dns_msg* msg;
 586         msg = dns_cache_lookup(qstate->env, qstate->qinfo.qname,
 587                 qstate->qinfo.qname_len, qstate->qinfo.qtype,
 588                 qstate->qinfo.qclass, qstate->query_flags,
 589                 qstate->region, qstate->env->scratch,
 590                 1 /* no partial messages with only a CNAME */
 591                 );
 592         if(!msg && qstate->env->neg_cache &&
 593                 iter_qname_indicates_dnssec(qstate->env, &qstate->qinfo)) {
 594                 /* lookup in negative cache; may result in
 595                  * NOERROR/NODATA or NXDOMAIN answers that need validation */
 596                 msg = val_neg_getmsg(qstate->env->neg_cache, &qstate->qinfo,
 597                         qstate->region, qstate->env->rrset_cache,
 598                         qstate->env->scratch_buffer,
 599                         *qstate->env->now, 1/*add SOA*/, NULL,
 600                         qstate->env->cfg);
 601         }
 602         if(!msg)
 603                 return 0;
 604         /* this is the returned msg */
 605         qstate->return_rcode = LDNS_RCODE_NOERROR;
 606         qstate->return_msg = msg;
 607         return 1;
 608 }
 609
 610 /**
 611  * Store query into the internal cache of unbound.
 612  */
 613 static void
 614 cachedb_intcache_store(struct module_qstate* qstate)
 615 {
 616         uint32_t store_flags = qstate->query_flags;
 617
 618         if(qstate->env->cfg->serve_expired)
 619                 store_flags |= DNSCACHE_STORE_ZEROTTL;
 620         if(!qstate->return_msg)
 621                 return;
 622         (void)dns_cache_store(qstate->env, &qstate->qinfo,
 623                 qstate->return_msg->rep, 0, qstate->prefetch_leeway, 0,
 624                 qstate->region, store_flags);
 625 }
 626
 627 /**
 628  * Handle a cachedb module event with a query
 629  * @param qstate: query state (from the mesh), passed between modules.
 630  *      contains qstate->env module environment with global caches and so on.
 631  * @param iq: query state specific for this module.  per-query.
 632  * @param ie: environment specific for this module.  global.
 633  * @param id: module id.
 634  */
 635 static void
 636 cachedb_handle_query(struct module_qstate* qstate,
 637         struct cachedb_qstate* ATTR_UNUSED(iq),
 638         struct cachedb_env* ie, int id)
 639 {
 640         /* check if we are enabled, and skip if so */
 641         if(!ie->enabled) {
 642                 /* pass request to next module */
 643                 qstate->ext_state[id] = module_wait_module;
 644                 return;
 645         }
 646
 647         if(qstate->blacklist || qstate->no_cache_lookup) {
 648                 /* cache is blacklisted or we are instructed from edns to not look */
 649                 /* pass request to next module */
 650                 qstate->ext_state[id] = module_wait_module;
 651                 return;
 652         }
 653
 654         /* lookup inside unbound's internal cache */
 655         if(cachedb_intcache_lookup(qstate)) {
 656                 if(verbosity >= VERB_ALGO) {
 657                         if(qstate->return_msg->rep)
 658                                 log_dns_msg("cachedb internal cache lookup",
 659                                         &qstate->return_msg->qinfo,
 660                                         qstate->return_msg->rep);
 661                         else log_info("cachedb internal cache lookup: rcode %s",
 662                                 sldns_lookup_by_id(sldns_rcodes, qstate->return_rcode)?
 663                                 sldns_lookup_by_id(sldns_rcodes, qstate->return_rcode)->name:"??");
 664                 }
 665                 /* we are done with the query */
 666                 qstate->ext_state[id] = module_finished;
 667                 return;
 668         }
 669
 670         /* ask backend cache to see if we have data */
 671         if(cachedb_extcache_lookup(qstate, ie)) {
 672                 if(verbosity >= VERB_ALGO)
 673                         log_dns_msg(ie->backend->name,
 674                                 &qstate->return_msg->qinfo,
 675                                 qstate->return_msg->rep);
 676                 /* store this result in internal cache */
 677                 cachedb_intcache_store(qstate);
 678                 /* we are done with the query */
 679                 qstate->ext_state[id] = module_finished;
 680                 return;
 681         }
 682
 683         /* no cache fetches */
 684         /* pass request to next module */
 685         qstate->ext_state[id] = module_wait_module;
 686 }
 687
 688 /**
 689  * Handle a cachedb module event with a response from the iterator.
 690  * @param qstate: query state (from the mesh), passed between modules.
 691  *      contains qstate->env module environment with global caches and so on.
 692  * @param iq: query state specific for this module.  per-query.
 693  * @param ie: environment specific for this module.  global.
 694  * @param id: module id.
 695  */
 696 static void
 697 cachedb_handle_response(struct module_qstate* qstate,
 698         struct cachedb_qstate* ATTR_UNUSED(iq), struct cachedb_env* ie, int id)
 699 {
 700         /* check if we are not enabled or instructed to not cache, and skip */
 701         if(!ie->enabled || qstate->no_cache_store) {
 702                 /* we are done with the query */
 703                 qstate->ext_state[id] = module_finished;
 704                 return;
 705         }
 706
 707         /* store the item into the backend cache */
 708         cachedb_extcache_store(qstate, ie);
 709
 710         /* we are done with the query */
 711         qstate->ext_state[id] = module_finished;
 712 }
 713
 714 void
 715 cachedb_operate(struct module_qstate* qstate, enum module_ev event, int id,
 716         struct outbound_entry* outbound)
 717 {
 718         struct cachedb_env* ie = (struct cachedb_env*)qstate->env->modinfo[id];
 719         struct cachedb_qstate* iq = (struct cachedb_qstate*)qstate->minfo[id];
 720         verbose(VERB_QUERY, "cachedb[module %d] operate: extstate:%s event:%s",
 721                 id, strextstate(qstate->ext_state[id]), strmodulevent(event));
 722         if(iq) log_query_info(VERB_QUERY, "cachedb operate: query",
 723                 &qstate->qinfo);
 724
 725         /* perform cachedb state machine */
 726         if((event == module_event_new || event == module_event_pass) &&
 727                 iq == NULL) {
 728                 if(!cachedb_new(qstate, id)) {
 729                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 730                         return;
 731                 }
 732                 iq = (struct cachedb_qstate*)qstate->minfo[id];
 733         }
 734         if(iq && (event == module_event_pass || event == module_event_new)) {
 735                 cachedb_handle_query(qstate, iq, ie, id);
 736                 return;
 737         }
 738         if(iq && (event == module_event_moddone)) {
 739                 cachedb_handle_response(qstate, iq, ie, id);
 740                 return;
 741         }
 742         if(iq && outbound) {
 743                 /* cachedb does not need to process responses at this time
 744                  * ignore it.
 745                 cachedb_process_response(qstate, iq, ie, id, outbound, event);
 746                 */
 747                 return;
 748         }
 749         if(event == module_event_error) {
 750                 verbose(VERB_ALGO, "got called with event error, giving up");
 751                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 752                 return;
 753         }
 754         if(!iq && (event == module_event_moddone)) {
 755                 /* during priming, module done but we never started */
 756                 qstate->ext_state[id] = module_finished;
 757                 return;
 758         }
 759
 760         log_err("bad event for cachedb");
 761         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 762 }
 763
 764 void
 765 cachedb_inform_super(struct module_qstate* ATTR_UNUSED(qstate),
 766         int ATTR_UNUSED(id), struct module_qstate* ATTR_UNUSED(super))
 767 {
 768         /* cachedb does not use subordinate requests at this time */
 769         verbose(VERB_ALGO, "cachedb inform_super was called");
 770 }
 771
 772 void
 773 cachedb_clear(struct module_qstate* qstate, int id)
 774 {
 775         struct cachedb_qstate* iq;
 776         if(!qstate)
 777                 return;
 778         iq = (struct cachedb_qstate*)qstate->minfo[id];
 779         if(iq) {
 780                 /* free contents of iq */
 781                 /* TODO */
 782         }
 783         qstate->minfo[id] = NULL;
 784 }
 785
 786 size_t
 787 cachedb_get_mem(struct module_env* env, int id)
 788 {
 789         struct cachedb_env* ie = (struct cachedb_env*)env->modinfo[id];
 790         if(!ie)
 791                 return 0;
 792         return sizeof(*ie); /* TODO - more mem */
 793 }
 794
 795 /**
 796  * The cachedb function block
 797  */
 798 static struct module_func_block cachedb_block = {
 799         "cachedb",
 800         &cachedb_init, &cachedb_deinit, &cachedb_operate,
 801         &cachedb_inform_super, &cachedb_clear, &cachedb_get_mem
 802 };
 803
 804 struct module_func_block*
 805 cachedb_get_funcblock(void)
 806 {
 807         return &cachedb_block;
 808 }
 809 #endif /* USE_CACHEDB */