Alexandre Lision | 8af73cb | 2013-12-10 14:11:20 -0500 | [diff] [blame] | 1 | /* $Id$ */ |
| 2 | /* |
| 3 | * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) |
| 4 | * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 19 | */ |
| 20 | #include <pjlib-util/srv_resolver.h> |
| 21 | #include <pjlib-util/errno.h> |
| 22 | #include <pj/array.h> |
| 23 | #include <pj/assert.h> |
| 24 | #include <pj/log.h> |
| 25 | #include <pj/os.h> |
| 26 | #include <pj/pool.h> |
| 27 | #include <pj/rand.h> |
| 28 | #include <pj/string.h> |
| 29 | |
| 30 | |
| 31 | #define THIS_FILE "srv_resolver.c" |
| 32 | |
| 33 | #define ADDR_MAX_COUNT PJ_DNS_MAX_IP_IN_A_REC |
| 34 | |
| 35 | struct common |
| 36 | { |
| 37 | pj_dns_type type; /**< Type of this structure.*/ |
| 38 | }; |
| 39 | |
| 40 | struct srv_target |
| 41 | { |
| 42 | struct common common; |
| 43 | pj_dns_srv_async_query *parent; |
| 44 | pj_str_t target_name; |
| 45 | pj_dns_async_query *q_a; |
| 46 | char target_buf[PJ_MAX_HOSTNAME]; |
| 47 | pj_str_t cname; |
| 48 | char cname_buf[PJ_MAX_HOSTNAME]; |
| 49 | unsigned port; |
| 50 | unsigned priority; |
| 51 | unsigned weight; |
| 52 | unsigned sum; |
| 53 | unsigned addr_cnt; |
| 54 | pj_in_addr addr[ADDR_MAX_COUNT]; |
| 55 | }; |
| 56 | |
| 57 | struct pj_dns_srv_async_query |
| 58 | { |
| 59 | struct common common; |
| 60 | char *objname; |
| 61 | |
| 62 | pj_dns_type dns_state; /**< DNS type being resolved. */ |
| 63 | pj_dns_resolver *resolver; /**< Resolver SIP instance. */ |
| 64 | void *token; |
| 65 | pj_dns_async_query *q_srv; |
| 66 | pj_dns_srv_resolver_cb *cb; |
| 67 | pj_status_t last_error; |
| 68 | |
| 69 | /* Original request: */ |
| 70 | unsigned option; |
| 71 | pj_str_t full_name; |
| 72 | pj_str_t domain_part; |
| 73 | pj_uint16_t def_port; |
| 74 | |
| 75 | /* SRV records and their resolved IP addresses: */ |
| 76 | unsigned srv_cnt; |
| 77 | struct srv_target srv[PJ_DNS_SRV_MAX_ADDR]; |
| 78 | |
| 79 | /* Number of hosts in SRV records that the IP address has been resolved */ |
| 80 | unsigned host_resolved; |
| 81 | |
| 82 | }; |
| 83 | |
| 84 | |
| 85 | /* Async resolver callback, forward decl. */ |
| 86 | static void dns_callback(void *user_data, |
| 87 | pj_status_t status, |
| 88 | pj_dns_parsed_packet *pkt); |
| 89 | |
| 90 | |
| 91 | |
| 92 | /* |
| 93 | * The public API to invoke DNS SRV resolution. |
| 94 | */ |
| 95 | PJ_DEF(pj_status_t) pj_dns_srv_resolve( const pj_str_t *domain_name, |
| 96 | const pj_str_t *res_name, |
| 97 | unsigned def_port, |
| 98 | pj_pool_t *pool, |
| 99 | pj_dns_resolver *resolver, |
| 100 | unsigned option, |
| 101 | void *token, |
| 102 | pj_dns_srv_resolver_cb *cb, |
| 103 | pj_dns_srv_async_query **p_query) |
| 104 | { |
| 105 | pj_size_t len; |
| 106 | pj_str_t target_name; |
| 107 | pj_dns_srv_async_query *query_job; |
| 108 | pj_status_t status; |
| 109 | |
| 110 | PJ_ASSERT_RETURN(domain_name && domain_name->slen && |
| 111 | res_name && res_name->slen && |
| 112 | pool && resolver && cb, PJ_EINVAL); |
| 113 | |
| 114 | /* Build full name */ |
| 115 | len = domain_name->slen + res_name->slen + 2; |
| 116 | target_name.ptr = (char*) pj_pool_alloc(pool, len); |
| 117 | pj_strcpy(&target_name, res_name); |
| 118 | if (res_name->ptr[res_name->slen-1] != '.') |
| 119 | pj_strcat2(&target_name, "."); |
| 120 | len = target_name.slen; |
| 121 | pj_strcat(&target_name, domain_name); |
| 122 | target_name.ptr[target_name.slen] = '\0'; |
| 123 | |
| 124 | |
| 125 | /* Build the query_job state */ |
| 126 | query_job = PJ_POOL_ZALLOC_T(pool, pj_dns_srv_async_query); |
| 127 | query_job->common.type = PJ_DNS_TYPE_SRV; |
| 128 | query_job->objname = target_name.ptr; |
| 129 | query_job->resolver = resolver; |
| 130 | query_job->token = token; |
| 131 | query_job->cb = cb; |
| 132 | query_job->option = option; |
| 133 | query_job->full_name = target_name; |
| 134 | query_job->domain_part.ptr = target_name.ptr + len; |
| 135 | query_job->domain_part.slen = target_name.slen - len; |
| 136 | query_job->def_port = (pj_uint16_t)def_port; |
| 137 | |
| 138 | /* Start the asynchronous query_job */ |
| 139 | |
| 140 | query_job->dns_state = PJ_DNS_TYPE_SRV; |
| 141 | |
| 142 | PJ_LOG(5, (query_job->objname, |
| 143 | "Starting async DNS %s query_job: target=%.*s:%d", |
| 144 | pj_dns_get_type_name(query_job->dns_state), |
| 145 | (int)target_name.slen, target_name.ptr, |
| 146 | def_port)); |
| 147 | |
| 148 | status = pj_dns_resolver_start_query(resolver, &target_name, |
| 149 | query_job->dns_state, 0, |
| 150 | &dns_callback, |
| 151 | query_job, &query_job->q_srv); |
| 152 | if (status==PJ_SUCCESS && p_query) |
| 153 | *p_query = query_job; |
| 154 | |
| 155 | return status; |
| 156 | } |
| 157 | |
| 158 | |
| 159 | /* |
| 160 | * Cancel pending query. |
| 161 | */ |
| 162 | PJ_DEF(pj_status_t) pj_dns_srv_cancel_query(pj_dns_srv_async_query *query, |
| 163 | pj_bool_t notify) |
| 164 | { |
| 165 | pj_bool_t has_pending = PJ_FALSE; |
| 166 | unsigned i; |
| 167 | |
| 168 | if (query->q_srv) { |
| 169 | pj_dns_resolver_cancel_query(query->q_srv, PJ_FALSE); |
| 170 | query->q_srv = NULL; |
| 171 | has_pending = PJ_TRUE; |
| 172 | } |
| 173 | |
| 174 | for (i=0; i<query->srv_cnt; ++i) { |
| 175 | struct srv_target *srv = &query->srv[i]; |
| 176 | if (srv->q_a) { |
| 177 | pj_dns_resolver_cancel_query(srv->q_a, PJ_FALSE); |
| 178 | srv->q_a = NULL; |
| 179 | has_pending = PJ_TRUE; |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | if (has_pending && notify && query->cb) { |
| 184 | (*query->cb)(query->token, PJ_ECANCELLED, NULL); |
| 185 | } |
| 186 | |
| 187 | return has_pending? PJ_SUCCESS : PJ_EINVALIDOP; |
| 188 | } |
| 189 | |
| 190 | |
| 191 | #define SWAP(type,ptr1,ptr2) if (ptr1 != ptr2) { \ |
| 192 | type tmp; \ |
| 193 | pj_memcpy(&tmp, ptr1, sizeof(type)); \ |
| 194 | pj_memcpy(ptr1, ptr2, sizeof(type)); \ |
| 195 | (ptr1)->target_name.ptr = (ptr1)->target_buf;\ |
| 196 | pj_memcpy(ptr2, &tmp, sizeof(type)); \ |
| 197 | (ptr2)->target_name.ptr = (ptr2)->target_buf;\ |
| 198 | } else {} |
| 199 | |
| 200 | |
| 201 | /* Build server entries in the query_job based on received SRV response */ |
| 202 | static void build_server_entries(pj_dns_srv_async_query *query_job, |
| 203 | pj_dns_parsed_packet *response) |
| 204 | { |
| 205 | unsigned i; |
| 206 | |
| 207 | /* Save the Resource Records in DNS answer into SRV targets. */ |
| 208 | query_job->srv_cnt = 0; |
| 209 | for (i=0; i<response->hdr.anscount && |
| 210 | query_job->srv_cnt < PJ_DNS_SRV_MAX_ADDR; ++i) |
| 211 | { |
| 212 | pj_dns_parsed_rr *rr = &response->ans[i]; |
| 213 | struct srv_target *srv = &query_job->srv[query_job->srv_cnt]; |
| 214 | |
| 215 | if (rr->type != PJ_DNS_TYPE_SRV) { |
| 216 | PJ_LOG(4,(query_job->objname, |
| 217 | "Received non SRV answer for SRV query_job!")); |
| 218 | continue; |
| 219 | } |
| 220 | |
| 221 | if (rr->rdata.srv.target.slen > PJ_MAX_HOSTNAME) { |
| 222 | PJ_LOG(4,(query_job->objname, "Hostname is too long!")); |
| 223 | continue; |
| 224 | } |
| 225 | |
| 226 | /* Build the SRV entry for RR */ |
| 227 | pj_bzero(srv, sizeof(*srv)); |
| 228 | srv->target_name.ptr = srv->target_buf; |
| 229 | pj_strncpy(&srv->target_name, &rr->rdata.srv.target, |
| 230 | sizeof(srv->target_buf)); |
| 231 | srv->port = rr->rdata.srv.port; |
| 232 | srv->priority = rr->rdata.srv.prio; |
| 233 | srv->weight = rr->rdata.srv.weight; |
| 234 | |
| 235 | ++query_job->srv_cnt; |
| 236 | } |
| 237 | |
| 238 | if (query_job->srv_cnt == 0) { |
| 239 | PJ_LOG(4,(query_job->objname, |
| 240 | "Could not find SRV record in DNS answer!")); |
| 241 | return; |
| 242 | } |
| 243 | |
| 244 | /* First pass: |
| 245 | * order the entries based on priority. |
| 246 | */ |
| 247 | for (i=0; i<query_job->srv_cnt-1; ++i) { |
| 248 | unsigned min = i, j; |
| 249 | for (j=i+1; j<query_job->srv_cnt; ++j) { |
| 250 | if (query_job->srv[j].priority < query_job->srv[min].priority) |
| 251 | min = j; |
| 252 | } |
| 253 | SWAP(struct srv_target, &query_job->srv[i], &query_job->srv[min]); |
| 254 | } |
| 255 | |
| 256 | /* Second pass: |
| 257 | * pick one host among hosts with the same priority, according |
| 258 | * to its weight. The idea is when one server fails, client should |
| 259 | * contact the next server with higher priority rather than contacting |
| 260 | * server with the same priority as the failed one. |
| 261 | * |
| 262 | * The algorithm for selecting server among servers with the same |
| 263 | * priority is described in RFC 2782. |
| 264 | */ |
| 265 | for (i=0; i<query_job->srv_cnt; ++i) { |
| 266 | unsigned j, count=1, sum; |
| 267 | |
| 268 | /* Calculate running sum for servers with the same priority */ |
| 269 | sum = query_job->srv[i].sum = query_job->srv[i].weight; |
| 270 | for (j=i+1; j<query_job->srv_cnt && |
| 271 | query_job->srv[j].priority == query_job->srv[i].priority; ++j) |
| 272 | { |
| 273 | sum += query_job->srv[j].weight; |
| 274 | query_job->srv[j].sum = sum; |
| 275 | ++count; |
| 276 | } |
| 277 | |
| 278 | if (count > 1) { |
| 279 | unsigned r; |
| 280 | |
| 281 | /* Elect one random number between zero and the total sum of |
| 282 | * weight (inclusive). |
| 283 | */ |
| 284 | r = pj_rand() % (sum + 1); |
| 285 | |
| 286 | /* Select the first server which running sum is greater than or |
| 287 | * equal to the random number. |
| 288 | */ |
| 289 | for (j=i; j<i+count; ++j) { |
| 290 | if (query_job->srv[j].sum >= r) |
| 291 | break; |
| 292 | } |
| 293 | |
| 294 | /* Must have selected one! */ |
| 295 | pj_assert(j != i+count); |
| 296 | |
| 297 | /* Put this entry in front (of entries with same priority) */ |
| 298 | SWAP(struct srv_target, &query_job->srv[i], &query_job->srv[j]); |
| 299 | |
| 300 | /* Remove all other entries (of the same priority) */ |
| 301 | while (count > 1) { |
| 302 | pj_array_erase(query_job->srv, sizeof(struct srv_target), |
| 303 | query_job->srv_cnt, i+1); |
| 304 | --count; |
| 305 | --query_job->srv_cnt; |
| 306 | } |
| 307 | } |
| 308 | } |
| 309 | |
| 310 | /* Since we've been moving around SRV entries, update the pointers |
| 311 | * in target_name. |
| 312 | */ |
| 313 | for (i=0; i<query_job->srv_cnt; ++i) { |
| 314 | query_job->srv[i].target_name.ptr = query_job->srv[i].target_buf; |
| 315 | } |
| 316 | |
| 317 | /* Check for Additional Info section if A records are available, and |
| 318 | * fill in the IP address (so that we won't need to resolve the A |
| 319 | * record with another DNS query_job). |
| 320 | */ |
| 321 | for (i=0; i<response->hdr.arcount; ++i) { |
| 322 | pj_dns_parsed_rr *rr = &response->arr[i]; |
| 323 | unsigned j; |
| 324 | |
| 325 | if (rr->type != PJ_DNS_TYPE_A) |
| 326 | continue; |
| 327 | |
| 328 | /* Yippeaiyee!! There is an "A" record! |
| 329 | * Update the IP address of the corresponding SRV record. |
| 330 | */ |
| 331 | for (j=0; j<query_job->srv_cnt; ++j) { |
| 332 | if (pj_stricmp(&rr->name, &query_job->srv[j].target_name)==0) { |
| 333 | unsigned cnt = query_job->srv[j].addr_cnt; |
| 334 | query_job->srv[j].addr[cnt].s_addr = rr->rdata.a.ip_addr.s_addr; |
| 335 | /* Only increment host_resolved once per SRV record */ |
| 336 | if (query_job->srv[j].addr_cnt == 0) |
| 337 | ++query_job->host_resolved; |
| 338 | ++query_job->srv[j].addr_cnt; |
| 339 | break; |
| 340 | } |
| 341 | } |
| 342 | |
| 343 | /* Not valid message; SRV entry might have been deleted in |
| 344 | * server selection process. |
| 345 | */ |
| 346 | /* |
| 347 | if (j == query_job->srv_cnt) { |
| 348 | PJ_LOG(4,(query_job->objname, |
| 349 | "Received DNS SRV answer with A record, but " |
| 350 | "couldn't find matching name (name=%.*s)", |
| 351 | (int)rr->name.slen, |
| 352 | rr->name.ptr)); |
| 353 | } |
| 354 | */ |
| 355 | } |
| 356 | |
| 357 | /* Rescan again the name specified in the SRV record to see if IP |
| 358 | * address is specified as the target name (unlikely, but well, who |
| 359 | * knows..). |
| 360 | */ |
| 361 | for (i=0; i<query_job->srv_cnt; ++i) { |
| 362 | pj_in_addr addr; |
| 363 | |
| 364 | if (query_job->srv[i].addr_cnt != 0) { |
| 365 | /* IP address already resolved */ |
| 366 | continue; |
| 367 | } |
| 368 | |
| 369 | if (pj_inet_aton(&query_job->srv[i].target_name, &addr) != 0) { |
| 370 | query_job->srv[i].addr[query_job->srv[i].addr_cnt++] = addr; |
| 371 | ++query_job->host_resolved; |
| 372 | } |
| 373 | } |
| 374 | |
| 375 | /* Print resolved entries to the log */ |
| 376 | PJ_LOG(5,(query_job->objname, |
| 377 | "SRV query_job for %.*s completed, " |
| 378 | "%d of %d total entries selected%c", |
| 379 | (int)query_job->full_name.slen, |
| 380 | query_job->full_name.ptr, |
| 381 | query_job->srv_cnt, |
| 382 | response->hdr.anscount, |
| 383 | (query_job->srv_cnt ? ':' : ' '))); |
| 384 | |
| 385 | for (i=0; i<query_job->srv_cnt; ++i) { |
| 386 | const char *addr; |
| 387 | |
| 388 | if (query_job->srv[i].addr_cnt != 0) |
| 389 | addr = pj_inet_ntoa(query_job->srv[i].addr[0]); |
| 390 | else |
| 391 | addr = "-"; |
| 392 | |
| 393 | PJ_LOG(5,(query_job->objname, |
| 394 | " %d: SRV %d %d %d %.*s (%s)", |
| 395 | i, query_job->srv[i].priority, |
| 396 | query_job->srv[i].weight, |
| 397 | query_job->srv[i].port, |
| 398 | (int)query_job->srv[i].target_name.slen, |
| 399 | query_job->srv[i].target_name.ptr, |
| 400 | addr)); |
| 401 | } |
| 402 | } |
| 403 | |
| 404 | |
| 405 | /* Start DNS A record queries for all SRV records in the query_job structure */ |
| 406 | static pj_status_t resolve_hostnames(pj_dns_srv_async_query *query_job) |
| 407 | { |
| 408 | unsigned i; |
| 409 | pj_status_t err=PJ_SUCCESS, status; |
| 410 | |
| 411 | query_job->dns_state = PJ_DNS_TYPE_A; |
| 412 | for (i=0; i<query_job->srv_cnt; ++i) { |
| 413 | struct srv_target *srv = &query_job->srv[i]; |
| 414 | |
| 415 | PJ_LOG(5, (query_job->objname, |
| 416 | "Starting async DNS A query_job for %.*s", |
| 417 | (int)srv->target_name.slen, |
| 418 | srv->target_name.ptr)); |
| 419 | |
| 420 | srv->common.type = PJ_DNS_TYPE_A; |
| 421 | srv->parent = query_job; |
| 422 | |
| 423 | status = pj_dns_resolver_start_query(query_job->resolver, |
| 424 | &srv->target_name, |
| 425 | PJ_DNS_TYPE_A, 0, |
| 426 | &dns_callback, |
| 427 | srv, &srv->q_a); |
| 428 | if (status != PJ_SUCCESS) { |
| 429 | query_job->host_resolved++; |
| 430 | err = status; |
| 431 | } |
| 432 | } |
| 433 | |
| 434 | return (query_job->host_resolved == query_job->srv_cnt) ? err : PJ_SUCCESS; |
| 435 | } |
| 436 | |
| 437 | /* |
| 438 | * This callback is called by PJLIB-UTIL DNS resolver when asynchronous |
| 439 | * query_job has completed (successfully or with error). |
| 440 | */ |
| 441 | static void dns_callback(void *user_data, |
| 442 | pj_status_t status, |
| 443 | pj_dns_parsed_packet *pkt) |
| 444 | { |
| 445 | struct common *common = (struct common*) user_data; |
| 446 | pj_dns_srv_async_query *query_job; |
| 447 | struct srv_target *srv = NULL; |
| 448 | unsigned i; |
| 449 | |
| 450 | if (common->type == PJ_DNS_TYPE_SRV) { |
| 451 | query_job = (pj_dns_srv_async_query*) common; |
| 452 | srv = NULL; |
| 453 | } else if (common->type == PJ_DNS_TYPE_A) { |
| 454 | srv = (struct srv_target*) common; |
| 455 | query_job = srv->parent; |
| 456 | } else { |
| 457 | pj_assert(!"Unexpected user data!"); |
| 458 | return; |
| 459 | } |
| 460 | |
| 461 | /* Proceed to next stage */ |
| 462 | if (query_job->dns_state == PJ_DNS_TYPE_SRV) { |
| 463 | |
| 464 | /* We are getting SRV response */ |
| 465 | |
| 466 | query_job->q_srv = NULL; |
| 467 | |
| 468 | if (status == PJ_SUCCESS && pkt->hdr.anscount != 0) { |
| 469 | /* Got SRV response, build server entry. If A records are available |
| 470 | * in additional records section of the DNS response, save them too. |
| 471 | */ |
| 472 | build_server_entries(query_job, pkt); |
| 473 | |
| 474 | } else if (status != PJ_SUCCESS) { |
| 475 | char errmsg[PJ_ERR_MSG_SIZE]; |
| 476 | |
| 477 | /* Update query_job last error */ |
| 478 | query_job->last_error = status; |
| 479 | |
| 480 | pj_strerror(status, errmsg, sizeof(errmsg)); |
| 481 | PJ_LOG(4,(query_job->objname, |
| 482 | "DNS SRV resolution failed for %.*s: %s", |
| 483 | (int)query_job->full_name.slen, |
| 484 | query_job->full_name.ptr, |
| 485 | errmsg)); |
| 486 | |
| 487 | /* Trigger error when fallback is disabled */ |
| 488 | if ((query_job->option & |
| 489 | (PJ_DNS_SRV_FALLBACK_A | PJ_DNS_SRV_FALLBACK_AAAA)) == 0) |
| 490 | { |
| 491 | goto on_error; |
| 492 | } |
| 493 | } |
| 494 | |
| 495 | /* If we can't build SRV record, assume the original target is |
| 496 | * an A record and resolve with DNS A resolution. |
| 497 | */ |
| 498 | if (query_job->srv_cnt == 0) { |
| 499 | /* Looks like we aren't getting any SRV responses. |
| 500 | * Resolve the original target as A record by creating a |
| 501 | * single "dummy" srv record and start the hostname resolution. |
| 502 | */ |
| 503 | PJ_LOG(4, (query_job->objname, |
| 504 | "DNS SRV resolution failed for %.*s, trying " |
| 505 | "resolving A record for %.*s", |
| 506 | (int)query_job->full_name.slen, |
| 507 | query_job->full_name.ptr, |
| 508 | (int)query_job->domain_part.slen, |
| 509 | query_job->domain_part.ptr)); |
| 510 | |
| 511 | /* Create a "dummy" srv record using the original target */ |
| 512 | i = query_job->srv_cnt++; |
| 513 | pj_bzero(&query_job->srv[i], sizeof(query_job->srv[i])); |
| 514 | query_job->srv[i].target_name = query_job->domain_part; |
| 515 | query_job->srv[i].priority = 0; |
| 516 | query_job->srv[i].weight = 0; |
| 517 | query_job->srv[i].port = query_job->def_port; |
| 518 | } |
| 519 | |
| 520 | |
| 521 | /* Resolve server hostnames (DNS A record) for hosts which don't have |
| 522 | * A record yet. |
| 523 | */ |
| 524 | if (query_job->host_resolved != query_job->srv_cnt) { |
| 525 | status = resolve_hostnames(query_job); |
| 526 | if (status != PJ_SUCCESS) |
| 527 | goto on_error; |
| 528 | |
| 529 | /* Must return now. Callback may have been called and query_job |
| 530 | * may have been destroyed. |
| 531 | */ |
| 532 | return; |
| 533 | } |
| 534 | |
| 535 | } else if (query_job->dns_state == PJ_DNS_TYPE_A) { |
| 536 | |
| 537 | /* Clear the outstanding job */ |
| 538 | srv->q_a = NULL; |
| 539 | |
| 540 | /* Check that we really have answer */ |
| 541 | if (status==PJ_SUCCESS && pkt->hdr.anscount != 0) { |
| 542 | pj_dns_a_record rec; |
| 543 | |
| 544 | /* Parse response */ |
| 545 | status = pj_dns_parse_a_response(pkt, &rec); |
| 546 | if (status != PJ_SUCCESS) |
| 547 | goto on_error; |
| 548 | |
| 549 | pj_assert(rec.addr_count != 0); |
| 550 | |
| 551 | /* Update CNAME alias, if present. */ |
| 552 | if (rec.alias.slen) { |
| 553 | pj_assert(rec.alias.slen <= (int)sizeof(srv->cname_buf)); |
| 554 | srv->cname.ptr = srv->cname_buf; |
| 555 | pj_strcpy(&srv->cname, &rec.alias); |
| 556 | } else { |
| 557 | srv->cname.slen = 0; |
| 558 | } |
| 559 | |
| 560 | /* Update IP address of the corresponding hostname or CNAME */ |
| 561 | if (srv->addr_cnt < ADDR_MAX_COUNT) { |
| 562 | srv->addr[srv->addr_cnt++].s_addr = rec.addr[0].s_addr; |
| 563 | |
| 564 | PJ_LOG(5,(query_job->objname, |
| 565 | "DNS A for %.*s: %s", |
| 566 | (int)srv->target_name.slen, |
| 567 | srv->target_name.ptr, |
| 568 | pj_inet_ntoa(rec.addr[0]))); |
| 569 | } |
| 570 | |
| 571 | /* Check for multiple IP addresses */ |
| 572 | for (i=1; i<rec.addr_count && srv->addr_cnt < ADDR_MAX_COUNT; ++i) |
| 573 | { |
| 574 | srv->addr[srv->addr_cnt++].s_addr = rec.addr[i].s_addr; |
| 575 | |
| 576 | PJ_LOG(5,(query_job->objname, |
| 577 | "Additional DNS A for %.*s: %s", |
| 578 | (int)srv->target_name.slen, |
| 579 | srv->target_name.ptr, |
| 580 | pj_inet_ntoa(rec.addr[i]))); |
| 581 | } |
| 582 | |
| 583 | } else if (status != PJ_SUCCESS) { |
| 584 | char errmsg[PJ_ERR_MSG_SIZE]; |
| 585 | |
| 586 | /* Update last error */ |
| 587 | query_job->last_error = status; |
| 588 | |
| 589 | /* Log error */ |
| 590 | pj_strerror(status, errmsg, sizeof(errmsg)); |
| 591 | PJ_LOG(4,(query_job->objname, "DNS A record resolution failed: %s", |
| 592 | errmsg)); |
| 593 | } |
| 594 | |
| 595 | ++query_job->host_resolved; |
| 596 | |
| 597 | } else { |
| 598 | pj_assert(!"Unexpected state!"); |
| 599 | query_job->last_error = status = PJ_EINVALIDOP; |
| 600 | goto on_error; |
| 601 | } |
| 602 | |
| 603 | /* Check if all hosts have been resolved */ |
| 604 | if (query_job->host_resolved == query_job->srv_cnt) { |
| 605 | /* Got all answers, build server addresses */ |
| 606 | pj_dns_srv_record srv_rec; |
| 607 | |
| 608 | srv_rec.count = 0; |
| 609 | for (i=0; i<query_job->srv_cnt; ++i) { |
| 610 | unsigned j; |
| 611 | struct srv_target *srv = &query_job->srv[i]; |
| 612 | |
| 613 | srv_rec.entry[srv_rec.count].priority = srv->priority; |
| 614 | srv_rec.entry[srv_rec.count].weight = srv->weight; |
| 615 | srv_rec.entry[srv_rec.count].port = (pj_uint16_t)srv->port ; |
| 616 | |
| 617 | srv_rec.entry[srv_rec.count].server.name = srv->target_name; |
| 618 | srv_rec.entry[srv_rec.count].server.alias = srv->cname; |
| 619 | srv_rec.entry[srv_rec.count].server.addr_count = 0; |
| 620 | |
| 621 | pj_assert(srv->addr_cnt <= PJ_DNS_MAX_IP_IN_A_REC); |
| 622 | |
| 623 | for (j=0; j<srv->addr_cnt; ++j) { |
| 624 | srv_rec.entry[srv_rec.count].server.addr[j].s_addr = |
| 625 | srv->addr[j].s_addr; |
| 626 | ++srv_rec.entry[srv_rec.count].server.addr_count; |
| 627 | } |
| 628 | |
| 629 | if (srv->addr_cnt > 0) { |
| 630 | ++srv_rec.count; |
| 631 | if (srv_rec.count == PJ_DNS_SRV_MAX_ADDR) |
| 632 | break; |
| 633 | } |
| 634 | } |
| 635 | |
| 636 | PJ_LOG(5,(query_job->objname, |
| 637 | "Server resolution complete, %d server entry(s) found", |
| 638 | srv_rec.count)); |
| 639 | |
| 640 | |
| 641 | if (srv_rec.count > 0) |
| 642 | status = PJ_SUCCESS; |
| 643 | else { |
| 644 | status = query_job->last_error; |
| 645 | if (status == PJ_SUCCESS) |
| 646 | status = PJLIB_UTIL_EDNSNOANSWERREC; |
| 647 | } |
| 648 | |
| 649 | /* Call the callback */ |
| 650 | (*query_job->cb)(query_job->token, status, &srv_rec); |
| 651 | } |
| 652 | |
| 653 | |
| 654 | return; |
| 655 | |
| 656 | on_error: |
| 657 | /* Check for failure */ |
| 658 | if (status != PJ_SUCCESS) { |
| 659 | char errmsg[PJ_ERR_MSG_SIZE]; |
| 660 | PJ_UNUSED_ARG(errmsg); |
| 661 | PJ_LOG(4,(query_job->objname, |
| 662 | "DNS %s record resolution error for '%.*s'." |
| 663 | " Err=%d (%s)", |
| 664 | pj_dns_get_type_name(query_job->dns_state), |
| 665 | (int)query_job->domain_part.slen, |
| 666 | query_job->domain_part.ptr, |
| 667 | status, |
| 668 | pj_strerror(status,errmsg,sizeof(errmsg)).ptr)); |
| 669 | (*query_job->cb)(query_job->token, status, NULL); |
| 670 | return; |
| 671 | } |
| 672 | } |
| 673 | |
| 674 | |