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 /* Some compilers do not define __BYTE_ORDER__, like IBM XLC on AIX */
  76 #ifndef be64toh
  77 #if defined(__sun) || defined(_AIX)
  78 #  if __BIG_ENDIAN__
  79 #    define be64toh(n) (n)
  80 #    define htobe64(n) (n)
  81 #  else
  82 #    define be64toh(n) (((uint64_t)htonl((n) & 0xFFFFFFFF) << 32) | htonl((n) >> 32))
  83 #    define htobe64(n) (((uint64_t)htonl((n) & 0xFFFFFFFF) << 32) | htonl((n) >> 32))
  84 #  endif
  85 #endif
  86 #endif /* be64toh */
  87
  88 /** the unit test testframe for cachedb, its module state contains
  89  * a cache for a couple queries (in memory). */
  90 struct testframe_moddata {
  91         /** lock for mutex */
  92         lock_basic_type lock;
  93         /** key for single stored data element, NULL if none */
  94         char* stored_key;
  95         /** data for single stored data element, NULL if none */
  96         uint8_t* stored_data;
  97         /** length of stored data */
  98         size_t stored_datalen;
  99 };
 100
 101 static int
 102 testframe_init(struct module_env* env, struct cachedb_env* cachedb_env)
 103 {
 104         struct testframe_moddata* d;
 105         (void)env;
 106         verbose(VERB_ALGO, "testframe_init");
 107         d = (struct testframe_moddata*)calloc(1,
 108                 sizeof(struct testframe_moddata));
 109         cachedb_env->backend_data = (void*)d;
 110         if(!cachedb_env->backend_data) {
 111                 log_err("out of memory");
 112                 return 0;
 113         }
 114         lock_basic_init(&d->lock);
 115         lock_protect(&d->lock, d, sizeof(*d));
 116         return 1;
 117 }
 118
 119 static void
 120 testframe_deinit(struct module_env* env, struct cachedb_env* cachedb_env)
 121 {
 122         struct testframe_moddata* d = (struct testframe_moddata*)
 123                 cachedb_env->backend_data;
 124         (void)env;
 125         verbose(VERB_ALGO, "testframe_deinit");
 126         if(!d)
 127                 return;
 128         lock_basic_destroy(&d->lock);
 129         free(d->stored_key);
 130         free(d->stored_data);
 131         free(d);
 132 }
 133
 134 static int
 135 testframe_lookup(struct module_env* env, struct cachedb_env* cachedb_env,
 136         char* key, struct sldns_buffer* result_buffer)
 137 {
 138         struct testframe_moddata* d = (struct testframe_moddata*)
 139                 cachedb_env->backend_data;
 140         (void)env;
 141         verbose(VERB_ALGO, "testframe_lookup of %s", key);
 142         lock_basic_lock(&d->lock);
 143         if(d->stored_key && strcmp(d->stored_key, key) == 0) {
 144                 if(d->stored_datalen > sldns_buffer_capacity(result_buffer)) {
 145                         lock_basic_unlock(&d->lock);
 146                         return 0; /* too large */
 147                 }
 148                 verbose(VERB_ALGO, "testframe_lookup found %d bytes",
 149                         (int)d->stored_datalen);
 150                 sldns_buffer_clear(result_buffer);
 151                 sldns_buffer_write(result_buffer, d->stored_data,
 152                         d->stored_datalen);
 153                 sldns_buffer_flip(result_buffer);
 154                 lock_basic_unlock(&d->lock);
 155                 return 1;
 156         }
 157         lock_basic_unlock(&d->lock);
 158         return 0;
 159 }
 160
 161 static void
 162 testframe_store(struct module_env* env, struct cachedb_env* cachedb_env,
 163         char* key, uint8_t* data, size_t data_len)
 164 {
 165         struct testframe_moddata* d = (struct testframe_moddata*)
 166                 cachedb_env->backend_data;
 167         (void)env;
 168         lock_basic_lock(&d->lock);
 169         verbose(VERB_ALGO, "testframe_store %s (%d bytes)", key, (int)data_len);
 170
 171         /* free old data element (if any) */
 172         free(d->stored_key);
 173         d->stored_key = NULL;
 174         free(d->stored_data);
 175         d->stored_data = NULL;
 176         d->stored_datalen = 0;
 177
 178         d->stored_data = memdup(data, data_len);
 179         if(!d->stored_data) {
 180                 lock_basic_unlock(&d->lock);
 181                 log_err("out of memory");
 182                 return;
 183         }
 184         d->stored_datalen = data_len;
 185         d->stored_key = strdup(key);
 186         if(!d->stored_key) {
 187                 free(d->stored_data);
 188                 d->stored_data = NULL;
 189                 d->stored_datalen = 0;
 190                 lock_basic_unlock(&d->lock);
 191                 return;
 192         }
 193         lock_basic_unlock(&d->lock);
 194         /* (key,data) successfully stored */
 195 }
 196
 197 /** The testframe backend is for unit tests */
 198 static struct cachedb_backend testframe_backend = { "testframe",
 199         testframe_init, testframe_deinit, testframe_lookup, testframe_store
 200 };
 201
 202 /** find a particular backend from possible backends */
 203 static struct cachedb_backend*
 204 cachedb_find_backend(const char* str)
 205 {
 206 #ifdef USE_REDIS
 207         if(strcmp(str, redis_backend.name) == 0)
 208                 return &redis_backend;
 209 #endif
 210         if(strcmp(str, testframe_backend.name) == 0)
 211                 return &testframe_backend;
 212         /* TODO add more backends here */
 213         return NULL;
 214 }
 215
 216 /** apply configuration to cachedb module 'global' state */
 217 static int
 218 cachedb_apply_cfg(struct cachedb_env* cachedb_env, struct config_file* cfg)
 219 {
 220         const char* backend_str = cfg->cachedb_backend;
 221
 222         /* If unspecified we use the in-memory test DB. */
 223         if(!backend_str)
 224                 backend_str = "testframe";
 225         cachedb_env->backend = cachedb_find_backend(backend_str);
 226         if(!cachedb_env->backend) {
 227                 log_err("cachedb: cannot find backend name '%s'", backend_str);
 228                 return 0;
 229         }
 230
 231         /* TODO see if more configuration needs to be applied or not */
 232         return 1;
 233 }
 234
 235 int
 236 cachedb_init(struct module_env* env, int id)
 237 {
 238         struct cachedb_env* cachedb_env = (struct cachedb_env*)calloc(1,
 239                 sizeof(struct cachedb_env));
 240         if(!cachedb_env) {
 241                 log_err("malloc failure");
 242                 return 0;
 243         }
 244         env->modinfo[id] = (void*)cachedb_env;
 245         if(!cachedb_apply_cfg(cachedb_env, env->cfg)) {
 246                 log_err("cachedb: could not apply configuration settings.");
 247                 free(cachedb_env);
 248                 env->modinfo[id] = NULL;
 249                 return 0;
 250         }
 251         /* see if a backend is selected */
 252         if(!cachedb_env->backend || !cachedb_env->backend->name)
 253                 return 1;
 254         if(!(*cachedb_env->backend->init)(env, cachedb_env)) {
 255                 log_err("cachedb: could not init %s backend",
 256                         cachedb_env->backend->name);
 257                 free(cachedb_env);
 258                 env->modinfo[id] = NULL;
 259                 return 0;
 260         }
 261         cachedb_env->enabled = 1;
 262         return 1;
 263 }
 264
 265 void
 266 cachedb_deinit(struct module_env* env, int id)
 267 {
 268         struct cachedb_env* cachedb_env;
 269         if(!env || !env->modinfo[id])
 270                 return;
 271         cachedb_env = (struct cachedb_env*)env->modinfo[id];
 272         /* free contents */
 273         /* TODO */
 274         if(cachedb_env->enabled) {
 275                 (*cachedb_env->backend->deinit)(env, cachedb_env);
 276         }
 277
 278         free(cachedb_env);
 279         env->modinfo[id] = NULL;
 280 }
 281
 282 /** new query for cachedb */
 283 static int
 284 cachedb_new(struct module_qstate* qstate, int id)
 285 {
 286         struct cachedb_qstate* iq = (struct cachedb_qstate*)regional_alloc(
 287                 qstate->region, sizeof(struct cachedb_qstate));
 288         qstate->minfo[id] = iq;
 289         if(!iq)
 290                 return 0;
 291         memset(iq, 0, sizeof(*iq));
 292         /* initialise it */
 293         /* TODO */
 294
 295         return 1;
 296 }
 297
 298 /**
 299  * Return an error
 300  * @param qstate: our query state
 301  * @param id: module id
 302  * @param rcode: error code (DNS errcode).
 303  * @return: 0 for use by caller, to make notation easy, like:
 304  *      return error_response(..).
 305  */
 306 static int
 307 error_response(struct module_qstate* qstate, int id, int rcode)
 308 {
 309         verbose(VERB_QUERY, "return error response %s",
 310                 sldns_lookup_by_id(sldns_rcodes, rcode)?
 311                 sldns_lookup_by_id(sldns_rcodes, rcode)->name:"??");
 312         qstate->return_rcode = rcode;
 313         qstate->return_msg = NULL;
 314         qstate->ext_state[id] = module_finished;
 315         return 0;
 316 }
 317
 318 /**
 319  * Hash the query name, type, class and dbacess-secret into lookup buffer.
 320  * @param qstate: query state with query info
 321  *      and env->cfg with secret.
 322  * @param buf: returned buffer with hash to lookup
 323  * @param len: length of the buffer.
 324  */
 325 static void
 326 calc_hash(struct module_qstate* qstate, char* buf, size_t len)
 327 {
 328         uint8_t clear[1024];
 329         size_t clen = 0;
 330         uint8_t hash[CACHEDB_HASHSIZE/8];
 331         const char* hex = "0123456789ABCDEF";
 332         const char* secret = qstate->env->cfg->cachedb_secret ?
 333                 qstate->env->cfg->cachedb_secret : "default";
 334         size_t i;
 335
 336         /* copy the hash info into the clear buffer */
 337         if(clen + qstate->qinfo.qname_len < sizeof(clear)) {
 338                 memmove(clear+clen, qstate->qinfo.qname,
 339                         qstate->qinfo.qname_len);
 340                 clen += qstate->qinfo.qname_len;
 341         }
 342         if(clen + 4 < sizeof(clear)) {
 343                 uint16_t t = htons(qstate->qinfo.qtype);
 344                 uint16_t c = htons(qstate->qinfo.qclass);
 345                 memmove(clear+clen, &t, 2);
 346                 memmove(clear+clen+2, &c, 2);
 347                 clen += 4;
 348         }
 349         if(secret && secret[0] && clen + strlen(secret) < sizeof(clear)) {
 350                 memmove(clear+clen, secret, strlen(secret));
 351                 clen += strlen(secret);
 352         }
 353
 354         /* hash the buffer */
 355         secalgo_hash_sha256(clear, clen, hash);
 356 #ifdef HAVE_EXPLICIT_BZERO
 357         explicit_bzero(clear, clen);
 358 #else
 359         memset(clear, 0, clen);
 360 #endif
 361
 362         /* hex encode output for portability (some online dbs need
 363          * no nulls, no control characters, and so on) */
 364         log_assert(len >= sizeof(hash)*2 + 1);
 365         (void)len;
 366         for(i=0; i<sizeof(hash); i++) {
 367                 buf[i*2] = hex[(hash[i]&0xf0)>>4];
 368                 buf[i*2+1] = hex[hash[i]&0x0f];
 369         }
 370         buf[sizeof(hash)*2] = 0;
 371 }
 372
 373 /** convert data from return_msg into the data buffer */
 374 static int
 375 prep_data(struct module_qstate* qstate, struct sldns_buffer* buf)
 376 {
 377         uint64_t timestamp, expiry;
 378         size_t oldlim;
 379         struct edns_data edns;
 380         memset(&edns, 0, sizeof(edns));
 381         edns.edns_present = 1;
 382         edns.bits = EDNS_DO;
 383         edns.ext_rcode = 0;
 384         edns.edns_version = EDNS_ADVERTISED_VERSION;
 385         edns.udp_size = EDNS_ADVERTISED_SIZE;
 386
 387         if(!qstate->return_msg || !qstate->return_msg->rep)
 388                 return 0;
 389         /* We don't store the reply if its TTL is 0 unless serve-expired is
 390          * enabled.  Such a reply won't be reusable and simply be a waste for
 391          * the backend.  It's also compatible with the default behavior of
 392          * dns_cache_store_msg(). */
 393         if(qstate->return_msg->rep->ttl == 0 &&
 394                 !qstate->env->cfg->serve_expired)
 395                 return 0;
 396         if(verbosity >= VERB_ALGO)
 397                 log_dns_msg("cachedb encoding", &qstate->return_msg->qinfo,
 398                         qstate->return_msg->rep);
 399         if(!reply_info_answer_encode(&qstate->return_msg->qinfo,
 400                 qstate->return_msg->rep, 0, qstate->query_flags,
 401                 buf, 0, 1, qstate->env->scratch, 65535, &edns, 1, 0))
 402                 return 0;
 403
 404         /* TTLs in the return_msg are relative to time(0) so we have to
 405          * store that, we also store the smallest ttl in the packet+time(0)
 406          * as the packet expiry time */
 407         /* qstate->return_msg->rep->ttl contains that relative shortest ttl */
 408         timestamp = (uint64_t)*qstate->env->now;
 409         expiry = timestamp + (uint64_t)qstate->return_msg->rep->ttl;
 410         timestamp = htobe64(timestamp);
 411         expiry = htobe64(expiry);
 412         oldlim = sldns_buffer_limit(buf);
 413         if(oldlim + sizeof(timestamp)+sizeof(expiry) >=
 414                 sldns_buffer_capacity(buf))
 415                 return 0; /* doesn't fit. */
 416         sldns_buffer_set_limit(buf, oldlim + sizeof(timestamp)+sizeof(expiry));
 417         sldns_buffer_write_at(buf, oldlim, &timestamp, sizeof(timestamp));
 418         sldns_buffer_write_at(buf, oldlim+sizeof(timestamp), &expiry,
 419                 sizeof(expiry));
 420
 421         return 1;
 422 }
 423
 424 /** check expiry, return true if matches OK */
 425 static int
 426 good_expiry_and_qinfo(struct module_qstate* qstate, struct sldns_buffer* buf)
 427 {
 428         uint64_t expiry;
 429         /* the expiry time is the last bytes of the buffer */
 430         if(sldns_buffer_limit(buf) < sizeof(expiry))
 431                 return 0;
 432         sldns_buffer_read_at(buf, sldns_buffer_limit(buf)-sizeof(expiry),
 433                 &expiry, sizeof(expiry));
 434         expiry = be64toh(expiry);
 435
 436         if((time_t)expiry < *qstate->env->now &&
 437                 !qstate->env->cfg->serve_expired)
 438                 return 0;
 439
 440         return 1;
 441 }
 442
 443 /* Adjust the TTL of the given RRset by 'subtract'.  If 'subtract' is
 444  * negative, set the TTL to 0. */
 445 static void
 446 packed_rrset_ttl_subtract(struct packed_rrset_data* data, time_t subtract)
 447 {
 448         size_t i;
 449         size_t total = data->count + data->rrsig_count;
 450         if(subtract >= 0 && data->ttl > subtract)
 451                 data->ttl -= subtract;
 452         else    data->ttl = 0;
 453         for(i=0; i<total; i++) {
 454                 if(subtract >= 0 && data->rr_ttl[i] > subtract)
 455                         data->rr_ttl[i] -= subtract;
 456                 else    data->rr_ttl[i] = 0;
 457         }
 458 }
 459
 460 /* Adjust the TTL of a DNS message and its RRs by 'adjust'.  If 'adjust' is
 461  * negative, set the TTLs to 0. */
 462 static void
 463 adjust_msg_ttl(struct dns_msg* msg, time_t adjust)
 464 {
 465         size_t i;
 466         if(adjust >= 0 && msg->rep->ttl > adjust)
 467                 msg->rep->ttl -= adjust;
 468         else    msg->rep->ttl = 0;
 469         msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
 470         msg->rep->serve_expired_ttl = msg->rep->ttl + SERVE_EXPIRED_TTL;
 471
 472         for(i=0; i<msg->rep->rrset_count; i++) {
 473                 packed_rrset_ttl_subtract((struct packed_rrset_data*)msg->
 474                         rep->rrsets[i]->entry.data, adjust);
 475         }
 476 }
 477
 478 /** convert dns message in buffer to return_msg */
 479 static int
 480 parse_data(struct module_qstate* qstate, struct sldns_buffer* buf)
 481 {
 482         struct msg_parse* prs;
 483         struct edns_data edns;
 484         uint64_t timestamp, expiry;
 485         time_t adjust;
 486         size_t lim = sldns_buffer_limit(buf);
 487         if(lim < LDNS_HEADER_SIZE+sizeof(timestamp)+sizeof(expiry))
 488                 return 0; /* too short */
 489
 490         /* remove timestamp and expiry from end */
 491         sldns_buffer_read_at(buf, lim-sizeof(expiry), &expiry, sizeof(expiry));
 492         sldns_buffer_read_at(buf, lim-sizeof(expiry)-sizeof(timestamp),
 493                 &timestamp, sizeof(timestamp));
 494         expiry = be64toh(expiry);
 495         timestamp = be64toh(timestamp);
 496
 497         /* parse DNS packet */
 498         regional_free_all(qstate->env->scratch);
 499         prs = (struct msg_parse*)regional_alloc(qstate->env->scratch,
 500                 sizeof(struct msg_parse));
 501         if(!prs)
 502                 return 0; /* out of memory */
 503         memset(prs, 0, sizeof(*prs));
 504         memset(&edns, 0, sizeof(edns));
 505         sldns_buffer_set_limit(buf, lim - sizeof(expiry)-sizeof(timestamp));
 506         if(parse_packet(buf, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) {
 507                 sldns_buffer_set_limit(buf, lim);
 508                 return 0;
 509         }
 510         if(parse_extract_edns(prs, &edns, qstate->env->scratch) !=
 511                 LDNS_RCODE_NOERROR) {
 512                 sldns_buffer_set_limit(buf, lim);
 513                 return 0;
 514         }
 515
 516         qstate->return_msg = dns_alloc_msg(buf, prs, qstate->region);
 517         sldns_buffer_set_limit(buf, lim);
 518         if(!qstate->return_msg)
 519                 return 0;
 520
 521         qstate->return_rcode = LDNS_RCODE_NOERROR;
 522
 523         /* see how much of the TTL expired, and remove it */
 524         if(*qstate->env->now <= (time_t)timestamp) {
 525                 verbose(VERB_ALGO, "cachedb msg adjust by zero");
 526                 return 1; /* message from the future (clock skew?) */
 527         }
 528         adjust = *qstate->env->now - (time_t)timestamp;
 529         if(qstate->return_msg->rep->ttl < adjust) {
 530                 verbose(VERB_ALGO, "cachedb msg expired");
 531                 /* If serve-expired is enabled, we still use an expired message
 532                  * setting the TTL to 0. */
 533                 if(qstate->env->cfg->serve_expired)
 534                         adjust = -1;
 535                 else
 536                         return 0; /* message expired */
 537         }
 538         verbose(VERB_ALGO, "cachedb msg adjusted down by %d", (int)adjust);
 539         adjust_msg_ttl(qstate->return_msg, adjust);
 540
 541         /* Similar to the unbound worker, if serve-expired is enabled and
 542          * the msg would be considered to be expired, mark the state so a
 543          * refetch will be scheduled.  The comparison between 'expiry' and
 544          * 'now' should be redundant given how these values were calculated,
 545          * but we check it just in case as does good_expiry_and_qinfo(). */
 546         if(qstate->env->cfg->serve_expired &&
 547                 (adjust == -1 || (time_t)expiry < *qstate->env->now)) {
 548                 qstate->need_refetch = 1;
 549         }
 550
 551         return 1;
 552 }
 553
 554 /**
 555  * Lookup the qstate.qinfo in extcache, store in qstate.return_msg.
 556  * return true if lookup was successful.
 557  */
 558 static int
 559 cachedb_extcache_lookup(struct module_qstate* qstate, struct cachedb_env* ie)
 560 {
 561         char key[(CACHEDB_HASHSIZE/8)*2+1];
 562         calc_hash(qstate, key, sizeof(key));
 563
 564         /* call backend to fetch data for key into scratch buffer */
 565         if( !(*ie->backend->lookup)(qstate->env, ie, key,
 566                 qstate->env->scratch_buffer)) {
 567                 return 0;
 568         }
 569
 570         /* check expiry date and check if query-data matches */
 571         if( !good_expiry_and_qinfo(qstate, qstate->env->scratch_buffer) ) {
 572                 return 0;
 573         }
 574
 575         /* parse dns message into return_msg */
 576         if( !parse_data(qstate, qstate->env->scratch_buffer) ) {
 577                 return 0;
 578         }
 579         return 1;
 580 }
 581
 582 /**
 583  * Store the qstate.return_msg in extcache for key qstate.info
 584  */
 585 static void
 586 cachedb_extcache_store(struct module_qstate* qstate, struct cachedb_env* ie)
 587 {
 588         char key[(CACHEDB_HASHSIZE/8)*2+1];
 589         calc_hash(qstate, key, sizeof(key));
 590
 591         /* prepare data in scratch buffer */
 592         if(!prep_data(qstate, qstate->env->scratch_buffer))
 593                 return;
 594
 595         /* call backend */
 596         (*ie->backend->store)(qstate->env, ie, key,
 597                 sldns_buffer_begin(qstate->env->scratch_buffer),
 598                 sldns_buffer_limit(qstate->env->scratch_buffer));
 599 }
 600
 601 /**
 602  * See if unbound's internal cache can answer the query
 603  */
 604 static int
 605 cachedb_intcache_lookup(struct module_qstate* qstate)
 606 {
 607         struct dns_msg* msg;
 608         msg = dns_cache_lookup(qstate->env, qstate->qinfo.qname,
 609                 qstate->qinfo.qname_len, qstate->qinfo.qtype,
 610                 qstate->qinfo.qclass, qstate->query_flags,
 611                 qstate->region, qstate->env->scratch,
 612                 1 /* no partial messages with only a CNAME */
 613                 );
 614         if(!msg && qstate->env->neg_cache &&
 615                 iter_qname_indicates_dnssec(qstate->env, &qstate->qinfo)) {
 616                 /* lookup in negative cache; may result in
 617                  * NOERROR/NODATA or NXDOMAIN answers that need validation */
 618                 msg = val_neg_getmsg(qstate->env->neg_cache, &qstate->qinfo,
 619                         qstate->region, qstate->env->rrset_cache,
 620                         qstate->env->scratch_buffer,
 621                         *qstate->env->now, 1/*add SOA*/, NULL,
 622                         qstate->env->cfg);
 623         }
 624         if(!msg)
 625                 return 0;
 626         /* this is the returned msg */
 627         qstate->return_rcode = LDNS_RCODE_NOERROR;
 628         qstate->return_msg = msg;
 629         return 1;
 630 }
 631
 632 /**
 633  * Store query into the internal cache of unbound.
 634  */
 635 static void
 636 cachedb_intcache_store(struct module_qstate* qstate)
 637 {
 638         uint32_t store_flags = qstate->query_flags;
 639
 640         if(qstate->env->cfg->serve_expired)
 641                 store_flags |= DNSCACHE_STORE_ZEROTTL;
 642         if(!qstate->return_msg)
 643                 return;
 644         (void)dns_cache_store(qstate->env, &qstate->qinfo,
 645                 qstate->return_msg->rep, 0, qstate->prefetch_leeway, 0,
 646                 qstate->region, store_flags);
 647 }
 648
 649 /**
 650  * Handle a cachedb module event with a query
 651  * @param qstate: query state (from the mesh), passed between modules.
 652  *      contains qstate->env module environment with global caches and so on.
 653  * @param iq: query state specific for this module.  per-query.
 654  * @param ie: environment specific for this module.  global.
 655  * @param id: module id.
 656  */
 657 static void
 658 cachedb_handle_query(struct module_qstate* qstate,
 659         struct cachedb_qstate* ATTR_UNUSED(iq),
 660         struct cachedb_env* ie, int id)
 661 {
 662         /* check if we are enabled, and skip if so */
 663         if(!ie->enabled) {
 664                 /* pass request to next module */
 665                 qstate->ext_state[id] = module_wait_module;
 666                 return;
 667         }
 668
 669         if(qstate->blacklist || qstate->no_cache_lookup) {
 670                 /* cache is blacklisted or we are instructed from edns to not look */
 671                 /* pass request to next module */
 672                 qstate->ext_state[id] = module_wait_module;
 673                 return;
 674         }
 675
 676         /* lookup inside unbound's internal cache */
 677         if(cachedb_intcache_lookup(qstate)) {
 678                 if(verbosity >= VERB_ALGO) {
 679                         if(qstate->return_msg->rep)
 680                                 log_dns_msg("cachedb internal cache lookup",
 681                                         &qstate->return_msg->qinfo,
 682                                         qstate->return_msg->rep);
 683                         else log_info("cachedb internal cache lookup: rcode %s",
 684                                 sldns_lookup_by_id(sldns_rcodes, qstate->return_rcode)?
 685                                 sldns_lookup_by_id(sldns_rcodes, qstate->return_rcode)->name:"??");
 686                 }
 687                 /* we are done with the query */
 688                 qstate->ext_state[id] = module_finished;
 689                 return;
 690         }
 691
 692         /* ask backend cache to see if we have data */
 693         if(cachedb_extcache_lookup(qstate, ie)) {
 694                 if(verbosity >= VERB_ALGO)
 695                         log_dns_msg(ie->backend->name,
 696                                 &qstate->return_msg->qinfo,
 697                                 qstate->return_msg->rep);
 698                 /* store this result in internal cache */
 699                 cachedb_intcache_store(qstate);
 700                 /* we are done with the query */
 701                 qstate->ext_state[id] = module_finished;
 702                 return;
 703         }
 704
 705         /* no cache fetches */
 706         /* pass request to next module */
 707         qstate->ext_state[id] = module_wait_module;
 708 }
 709
 710 /**
 711  * Handle a cachedb module event with a response from the iterator.
 712  * @param qstate: query state (from the mesh), passed between modules.
 713  *      contains qstate->env module environment with global caches and so on.
 714  * @param iq: query state specific for this module.  per-query.
 715  * @param ie: environment specific for this module.  global.
 716  * @param id: module id.
 717  */
 718 static void
 719 cachedb_handle_response(struct module_qstate* qstate,
 720         struct cachedb_qstate* ATTR_UNUSED(iq), struct cachedb_env* ie, int id)
 721 {
 722         /* check if we are not enabled or instructed to not cache, and skip */
 723         if(!ie->enabled || qstate->no_cache_store) {
 724                 /* we are done with the query */
 725                 qstate->ext_state[id] = module_finished;
 726                 return;
 727         }
 728
 729         /* store the item into the backend cache */
 730         cachedb_extcache_store(qstate, ie);
 731
 732         /* we are done with the query */
 733         qstate->ext_state[id] = module_finished;
 734 }
 735
 736 void
 737 cachedb_operate(struct module_qstate* qstate, enum module_ev event, int id,
 738         struct outbound_entry* outbound)
 739 {
 740         struct cachedb_env* ie = (struct cachedb_env*)qstate->env->modinfo[id];
 741         struct cachedb_qstate* iq = (struct cachedb_qstate*)qstate->minfo[id];
 742         verbose(VERB_QUERY, "cachedb[module %d] operate: extstate:%s event:%s",
 743                 id, strextstate(qstate->ext_state[id]), strmodulevent(event));
 744         if(iq) log_query_info(VERB_QUERY, "cachedb operate: query",
 745                 &qstate->qinfo);
 746
 747         /* perform cachedb state machine */
 748         if((event == module_event_new || event == module_event_pass) &&
 749                 iq == NULL) {
 750                 if(!cachedb_new(qstate, id)) {
 751                         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 752                         return;
 753                 }
 754                 iq = (struct cachedb_qstate*)qstate->minfo[id];
 755         }
 756         if(iq && (event == module_event_pass || event == module_event_new)) {
 757                 cachedb_handle_query(qstate, iq, ie, id);
 758                 return;
 759         }
 760         if(iq && (event == module_event_moddone)) {
 761                 cachedb_handle_response(qstate, iq, ie, id);
 762                 return;
 763         }
 764         if(iq && outbound) {
 765                 /* cachedb does not need to process responses at this time
 766                  * ignore it.
 767                 cachedb_process_response(qstate, iq, ie, id, outbound, event);
 768                 */
 769                 return;
 770         }
 771         if(event == module_event_error) {
 772                 verbose(VERB_ALGO, "got called with event error, giving up");
 773                 (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 774                 return;
 775         }
 776         if(!iq && (event == module_event_moddone)) {
 777                 /* during priming, module done but we never started */
 778                 qstate->ext_state[id] = module_finished;
 779                 return;
 780         }
 781
 782         log_err("bad event for cachedb");
 783         (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
 784 }
 785
 786 void
 787 cachedb_inform_super(struct module_qstate* ATTR_UNUSED(qstate),
 788         int ATTR_UNUSED(id), struct module_qstate* ATTR_UNUSED(super))
 789 {
 790         /* cachedb does not use subordinate requests at this time */
 791         verbose(VERB_ALGO, "cachedb inform_super was called");
 792 }
 793
 794 void
 795 cachedb_clear(struct module_qstate* qstate, int id)
 796 {
 797         struct cachedb_qstate* iq;
 798         if(!qstate)
 799                 return;
 800         iq = (struct cachedb_qstate*)qstate->minfo[id];
 801         if(iq) {
 802                 /* free contents of iq */
 803                 /* TODO */
 804         }
 805         qstate->minfo[id] = NULL;
 806 }
 807
 808 size_t
 809 cachedb_get_mem(struct module_env* env, int id)
 810 {
 811         struct cachedb_env* ie = (struct cachedb_env*)env->modinfo[id];
 812         if(!ie)
 813                 return 0;
 814         return sizeof(*ie); /* TODO - more mem */
 815 }
 816
 817 /**
 818  * The cachedb function block
 819  */
 820 static struct module_func_block cachedb_block = {
 821         "cachedb",
 822         &cachedb_init, &cachedb_deinit, &cachedb_operate,
 823         &cachedb_inform_super, &cachedb_clear, &cachedb_get_mem
 824 };
 825
 826 struct module_func_block*
 827 cachedb_get_funcblock(void)
 828 {
 829         return &cachedb_block;
 830 }
 831 #endif /* USE_CACHEDB */