Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [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/resolver.h> |
| 21 | #include <pjlib-util/errno.h> |
| 22 | #include <pj/assert.h> |
| 23 | #include <pj/ctype.h> |
| 24 | #include <pj/except.h> |
| 25 | #include <pj/hash.h> |
| 26 | #include <pj/ioqueue.h> |
| 27 | #include <pj/log.h> |
| 28 | #include <pj/os.h> |
| 29 | #include <pj/pool.h> |
| 30 | #include <pj/pool_buf.h> |
| 31 | #include <pj/rand.h> |
| 32 | #include <pj/string.h> |
| 33 | #include <pj/sock.h> |
| 34 | #include <pj/timer.h> |
| 35 | |
| 36 | |
| 37 | #define THIS_FILE "resolver.c" |
| 38 | |
| 39 | |
| 40 | /* Check that maximum DNS nameservers is not too large. |
| 41 | * This has got todo with the datatype to index the nameserver in the query. |
| 42 | */ |
| 43 | #if PJ_DNS_RESOLVER_MAX_NS > 256 |
| 44 | # error "PJ_DNS_RESOLVER_MAX_NS is too large (max=256)" |
| 45 | #endif |
| 46 | |
| 47 | |
| 48 | #define RES_HASH_TABLE_SIZE 127 /**< Hash table size (must be 2^n-1 */ |
| 49 | #define PORT 53 /**< Default NS port. */ |
| 50 | #define Q_HASH_TABLE_SIZE 127 /**< Query hash table size */ |
| 51 | #define TIMER_SIZE 127 /**< Initial number of timers. */ |
| 52 | #define MAX_FD 3 /**< Maximum internal sockets. */ |
| 53 | |
| 54 | #define RES_BUF_SZ PJ_DNS_RESOLVER_RES_BUF_SIZE |
| 55 | #define UDPSZ PJ_DNS_RESOLVER_MAX_UDP_SIZE |
| 56 | #define TMP_SZ PJ_DNS_RESOLVER_TMP_BUF_SIZE |
| 57 | |
| 58 | |
| 59 | /* Nameserver state */ |
| 60 | enum ns_state |
| 61 | { |
| 62 | STATE_PROBING, |
| 63 | STATE_ACTIVE, |
| 64 | STATE_BAD, |
| 65 | }; |
| 66 | |
| 67 | static const char *state_names[3] = |
| 68 | { |
| 69 | "Probing", |
| 70 | "Active", |
| 71 | "Bad" |
| 72 | }; |
| 73 | |
| 74 | |
| 75 | /* |
| 76 | * Each nameserver entry. |
| 77 | * A name server is identified by its socket address (IP and port). |
| 78 | * Each NS will have a flag to indicate whether it's properly functioning. |
| 79 | */ |
| 80 | struct nameserver |
| 81 | { |
| 82 | pj_sockaddr_in addr; /**< Server address. */ |
| 83 | |
| 84 | enum ns_state state; /**< Nameserver state. */ |
| 85 | pj_time_val state_expiry; /**< Time set next state. */ |
| 86 | pj_time_val rt_delay; /**< Response time. */ |
| 87 | |
| 88 | |
| 89 | /* For calculating rt_delay: */ |
| 90 | pj_uint16_t q_id; /**< Query ID. */ |
| 91 | pj_time_val sent_time; /**< Time this query is sent. */ |
| 92 | }; |
| 93 | |
| 94 | |
| 95 | /* Child query list head |
| 96 | * See comments on pj_dns_async_query below. |
| 97 | */ |
| 98 | struct query_head |
| 99 | { |
| 100 | PJ_DECL_LIST_MEMBER(pj_dns_async_query); |
| 101 | }; |
| 102 | |
| 103 | |
| 104 | /* Key to look for outstanding query and/or cached response */ |
| 105 | struct res_key |
| 106 | { |
| 107 | pj_uint16_t qtype; /**< Query type. */ |
| 108 | char name[PJ_MAX_HOSTNAME]; /**< Name being queried */ |
| 109 | }; |
| 110 | |
| 111 | |
| 112 | /* |
| 113 | * This represents each asynchronous query entry. |
| 114 | * This entry will be put in two hash tables, the first one keyed on the DNS |
| 115 | * transaction ID to match response with the query, and the second one keyed |
| 116 | * on "res_key" structure above to match a new request against outstanding |
| 117 | * requests. |
| 118 | * |
| 119 | * An asynchronous entry may have child entries; child entries are subsequent |
| 120 | * queries to the same resource while there is pending query on the same |
| 121 | * DNS resource name and type. When a query has child entries, once the |
| 122 | * response is received (or error occurs), the response will trigger callback |
| 123 | * invocations for all childs entries. |
| 124 | * |
| 125 | * Note: when application cancels the query, the callback member will be |
| 126 | * set to NULL, but for simplicity, the query will be let running. |
| 127 | */ |
| 128 | struct pj_dns_async_query |
| 129 | { |
| 130 | PJ_DECL_LIST_MEMBER(pj_dns_async_query); /**< List member. */ |
| 131 | |
| 132 | pj_dns_resolver *resolver; /**< The resolver instance. */ |
| 133 | pj_uint16_t id; /**< Transaction ID. */ |
| 134 | |
| 135 | unsigned transmit_cnt; /**< Number of transmissions. */ |
| 136 | |
| 137 | struct res_key key; /**< Key to index this query. */ |
| 138 | pj_hash_entry_buf hbufid; /**< Hash buffer 1 */ |
| 139 | pj_hash_entry_buf hbufkey; /**< Hash buffer 2 */ |
| 140 | pj_timer_entry timer_entry; /**< Timer to manage timeouts */ |
| 141 | unsigned options; /**< Query options. */ |
| 142 | void *user_data; /**< Application data. */ |
| 143 | pj_dns_callback *cb; /**< Callback to be called. */ |
| 144 | struct query_head child_head; /**< Child queries list head. */ |
| 145 | }; |
| 146 | |
| 147 | |
| 148 | /* This structure is used to keep cached response entry. |
| 149 | * The cache is a hash table keyed on "res_key" structure above. |
| 150 | */ |
| 151 | struct cached_res |
| 152 | { |
| 153 | PJ_DECL_LIST_MEMBER(struct cached_res); |
| 154 | |
| 155 | pj_pool_t *pool; /**< Cache's pool. */ |
| 156 | struct res_key key; /**< Resource key. */ |
| 157 | pj_hash_entry_buf hbuf; /**< Hash buffer */ |
| 158 | pj_time_val expiry_time; /**< Expiration time. */ |
| 159 | pj_dns_parsed_packet *pkt; /**< The response packet. */ |
| 160 | unsigned ref_cnt; /**< Reference counter. */ |
| 161 | }; |
| 162 | |
| 163 | |
| 164 | /* Resolver entry */ |
| 165 | struct pj_dns_resolver |
| 166 | { |
| 167 | pj_str_t name; /**< Resolver instance name for id. */ |
| 168 | |
| 169 | /* Internals */ |
| 170 | pj_pool_t *pool; /**< Internal pool. */ |
| 171 | pj_mutex_t *mutex; /**< Mutex protection. */ |
| 172 | pj_bool_t own_timer; /**< Do we own timer? */ |
| 173 | pj_timer_heap_t *timer; /**< Timer instance. */ |
| 174 | pj_bool_t own_ioqueue; /**< Do we own ioqueue? */ |
| 175 | pj_ioqueue_t *ioqueue; /**< Ioqueue instance. */ |
| 176 | char tmp_pool[TMP_SZ];/**< Temporary pool buffer. */ |
| 177 | |
| 178 | /* Socket */ |
| 179 | pj_sock_t udp_sock; /**< UDP socket. */ |
| 180 | pj_ioqueue_key_t *udp_key; /**< UDP socket ioqueue key. */ |
| 181 | unsigned char udp_rx_pkt[UDPSZ];/**< UDP receive buffer. */ |
| 182 | unsigned char udp_tx_pkt[UDPSZ];/**< UDP receive buffer. */ |
| 183 | pj_ssize_t udp_len; /**< Length of received packet. */ |
| 184 | pj_ioqueue_op_key_t udp_op_rx_key; /**< UDP read operation key. */ |
| 185 | pj_ioqueue_op_key_t udp_op_tx_key; /**< UDP write operation key. */ |
| 186 | pj_sockaddr_in udp_src_addr; /**< Source address of packet */ |
| 187 | int udp_addr_len; /**< Source address length. */ |
| 188 | |
| 189 | /* Settings */ |
| 190 | pj_dns_settings settings; /**< Resolver settings. */ |
| 191 | |
| 192 | /* Nameservers */ |
| 193 | unsigned ns_count; /**< Number of name servers. */ |
| 194 | struct nameserver ns[PJ_DNS_RESOLVER_MAX_NS]; /**< Array of NS. */ |
| 195 | |
| 196 | /* Last DNS transaction ID used. */ |
| 197 | pj_uint16_t last_id; |
| 198 | |
| 199 | /* Hash table for cached response */ |
| 200 | pj_hash_table_t *hrescache; /**< Cached response in hash table */ |
| 201 | |
| 202 | /* Pending asynchronous query, hashed by transaction ID. */ |
| 203 | pj_hash_table_t *hquerybyid; |
| 204 | |
| 205 | /* Pending asynchronous query, hashed by "res_key" */ |
| 206 | pj_hash_table_t *hquerybyres; |
| 207 | |
| 208 | /* Query entries free list */ |
| 209 | struct query_head query_free_nodes; |
| 210 | }; |
| 211 | |
| 212 | |
| 213 | /* Callback from ioqueue when packet is received */ |
| 214 | static void on_read_complete(pj_ioqueue_key_t *key, |
| 215 | pj_ioqueue_op_key_t *op_key, |
| 216 | pj_ssize_t bytes_read); |
| 217 | |
| 218 | /* Callback to be called when query has timed out */ |
| 219 | static void on_timeout( pj_timer_heap_t *timer_heap, |
| 220 | struct pj_timer_entry *entry); |
| 221 | |
| 222 | /* Select which nameserver to use */ |
| 223 | static pj_status_t select_nameservers(pj_dns_resolver *resolver, |
| 224 | unsigned *count, |
| 225 | unsigned servers[]); |
| 226 | |
| 227 | |
| 228 | /* Close UDP socket */ |
| 229 | static void close_sock(pj_dns_resolver *resv) |
| 230 | { |
| 231 | /* Close existing socket */ |
| 232 | if (resv->udp_key != NULL) { |
| 233 | pj_ioqueue_unregister(resv->udp_key); |
| 234 | resv->udp_key = NULL; |
| 235 | resv->udp_sock = PJ_INVALID_SOCKET; |
| 236 | } else if (resv->udp_sock != PJ_INVALID_SOCKET) { |
| 237 | pj_sock_close(resv->udp_sock); |
| 238 | resv->udp_sock = PJ_INVALID_SOCKET; |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | |
| 243 | /* Initialize UDP socket */ |
| 244 | static pj_status_t init_sock(pj_dns_resolver *resv) |
| 245 | { |
| 246 | pj_ioqueue_callback socket_cb; |
| 247 | pj_status_t status; |
| 248 | |
| 249 | /* Create the UDP socket */ |
| 250 | status = pj_sock_socket(pj_AF_INET(), pj_SOCK_DGRAM(), 0, &resv->udp_sock); |
| 251 | if (status != PJ_SUCCESS) |
| 252 | return status; |
| 253 | |
| 254 | /* Bind to any address/port */ |
| 255 | status = pj_sock_bind_in(resv->udp_sock, 0, 0); |
| 256 | if (status != PJ_SUCCESS) |
| 257 | return status; |
| 258 | |
| 259 | /* Register to ioqueue */ |
| 260 | pj_bzero(&socket_cb, sizeof(socket_cb)); |
| 261 | socket_cb.on_read_complete = &on_read_complete; |
| 262 | status = pj_ioqueue_register_sock(resv->pool, resv->ioqueue, |
| 263 | resv->udp_sock, resv, &socket_cb, |
| 264 | &resv->udp_key); |
| 265 | if (status != PJ_SUCCESS) |
| 266 | return status; |
| 267 | |
| 268 | pj_ioqueue_op_key_init(&resv->udp_op_rx_key, sizeof(resv->udp_op_rx_key)); |
| 269 | pj_ioqueue_op_key_init(&resv->udp_op_tx_key, sizeof(resv->udp_op_tx_key)); |
| 270 | |
| 271 | /* Start asynchronous read to the UDP socket */ |
| 272 | resv->udp_len = sizeof(resv->udp_rx_pkt); |
| 273 | resv->udp_addr_len = sizeof(resv->udp_src_addr); |
| 274 | status = pj_ioqueue_recvfrom(resv->udp_key, &resv->udp_op_rx_key, |
| 275 | resv->udp_rx_pkt, &resv->udp_len, |
| 276 | PJ_IOQUEUE_ALWAYS_ASYNC, |
| 277 | &resv->udp_src_addr, &resv->udp_addr_len); |
| 278 | if (status != PJ_EPENDING) |
| 279 | return status; |
| 280 | |
| 281 | return PJ_SUCCESS; |
| 282 | } |
| 283 | |
| 284 | |
| 285 | /* Initialize DNS settings with default values */ |
| 286 | PJ_DEF(void) pj_dns_settings_default(pj_dns_settings *s) |
| 287 | { |
| 288 | pj_bzero(s, sizeof(pj_dns_settings)); |
| 289 | s->qretr_delay = PJ_DNS_RESOLVER_QUERY_RETRANSMIT_DELAY; |
| 290 | s->qretr_count = PJ_DNS_RESOLVER_QUERY_RETRANSMIT_COUNT; |
| 291 | s->cache_max_ttl = PJ_DNS_RESOLVER_MAX_TTL; |
| 292 | s->good_ns_ttl = PJ_DNS_RESOLVER_GOOD_NS_TTL; |
| 293 | s->bad_ns_ttl = PJ_DNS_RESOLVER_BAD_NS_TTL; |
| 294 | } |
| 295 | |
| 296 | |
| 297 | /* |
| 298 | * Create the resolver. |
| 299 | */ |
| 300 | PJ_DEF(pj_status_t) pj_dns_resolver_create( pj_pool_factory *pf, |
| 301 | const char *name, |
| 302 | unsigned options, |
| 303 | pj_timer_heap_t *timer, |
| 304 | pj_ioqueue_t *ioqueue, |
| 305 | pj_dns_resolver **p_resolver) |
| 306 | { |
| 307 | pj_pool_t *pool; |
| 308 | pj_dns_resolver *resv; |
| 309 | pj_status_t status; |
| 310 | |
| 311 | /* Sanity check */ |
| 312 | PJ_ASSERT_RETURN(pf && p_resolver, PJ_EINVAL); |
| 313 | |
| 314 | if (name == NULL) |
| 315 | name = THIS_FILE; |
| 316 | |
| 317 | /* Create and initialize resolver instance */ |
| 318 | pool = pj_pool_create(pf, name, 4000, 4000, NULL); |
| 319 | if (!pool) |
| 320 | return PJ_ENOMEM; |
| 321 | |
| 322 | /* Create pool and name */ |
| 323 | resv = PJ_POOL_ZALLOC_T(pool, struct pj_dns_resolver); |
| 324 | resv->pool = pool; |
| 325 | resv->udp_sock = PJ_INVALID_SOCKET; |
| 326 | pj_strdup2_with_null(pool, &resv->name, name); |
| 327 | |
| 328 | /* Create the mutex */ |
| 329 | status = pj_mutex_create_recursive(pool, name, &resv->mutex); |
| 330 | if (status != PJ_SUCCESS) |
| 331 | goto on_error; |
| 332 | |
| 333 | /* Timer, ioqueue, and settings */ |
| 334 | resv->timer = timer; |
| 335 | resv->ioqueue = ioqueue; |
| 336 | resv->last_id = 1; |
| 337 | |
| 338 | pj_dns_settings_default(&resv->settings); |
| 339 | resv->settings.options = options; |
| 340 | |
| 341 | /* Create the timer heap if one is not specified */ |
| 342 | if (resv->timer == NULL) { |
| 343 | status = pj_timer_heap_create(pool, TIMER_SIZE, &resv->timer); |
| 344 | if (status != PJ_SUCCESS) |
| 345 | goto on_error; |
| 346 | } |
| 347 | |
| 348 | /* Create the ioqueue if one is not specified */ |
| 349 | if (resv->ioqueue == NULL) { |
| 350 | status = pj_ioqueue_create(pool, MAX_FD, &resv->ioqueue); |
| 351 | if (status != PJ_SUCCESS) |
| 352 | goto on_error; |
| 353 | } |
| 354 | |
| 355 | /* Response cache hash table */ |
| 356 | resv->hrescache = pj_hash_create(pool, RES_HASH_TABLE_SIZE); |
| 357 | |
| 358 | /* Query hash table and free list. */ |
| 359 | resv->hquerybyid = pj_hash_create(pool, Q_HASH_TABLE_SIZE); |
| 360 | resv->hquerybyres = pj_hash_create(pool, Q_HASH_TABLE_SIZE); |
| 361 | pj_list_init(&resv->query_free_nodes); |
| 362 | |
| 363 | /* Initialize the UDP socket */ |
| 364 | status = init_sock(resv); |
| 365 | if (status != PJ_SUCCESS) |
| 366 | goto on_error; |
| 367 | |
| 368 | /* Looks like everything is okay */ |
| 369 | *p_resolver = resv; |
| 370 | return PJ_SUCCESS; |
| 371 | |
| 372 | on_error: |
| 373 | pj_dns_resolver_destroy(resv, PJ_FALSE); |
| 374 | return status; |
| 375 | } |
| 376 | |
| 377 | |
| 378 | /* |
| 379 | * Destroy DNS resolver instance. |
| 380 | */ |
| 381 | PJ_DEF(pj_status_t) pj_dns_resolver_destroy( pj_dns_resolver *resolver, |
| 382 | pj_bool_t notify) |
| 383 | { |
| 384 | pj_hash_iterator_t it_buf, *it; |
| 385 | PJ_ASSERT_RETURN(resolver, PJ_EINVAL); |
| 386 | |
| 387 | if (notify) { |
| 388 | /* |
| 389 | * Notify pending queries if requested. |
| 390 | */ |
| 391 | it = pj_hash_first(resolver->hquerybyid, &it_buf); |
| 392 | while (it) { |
| 393 | pj_dns_async_query *q = (pj_dns_async_query *) |
| 394 | pj_hash_this(resolver->hquerybyid, it); |
| 395 | pj_dns_async_query *cq; |
| 396 | if (q->cb) |
| 397 | (*q->cb)(q->user_data, PJ_ECANCELLED, NULL); |
| 398 | |
| 399 | cq = q->child_head.next; |
| 400 | while (cq != (pj_dns_async_query*)&q->child_head) { |
| 401 | if (cq->cb) |
| 402 | (*cq->cb)(cq->user_data, PJ_ECANCELLED, NULL); |
| 403 | cq = cq->next; |
| 404 | } |
| 405 | it = pj_hash_next(resolver->hquerybyid, it); |
| 406 | } |
| 407 | } |
| 408 | |
| 409 | /* Destroy cached entries */ |
| 410 | it = pj_hash_first(resolver->hrescache, &it_buf); |
| 411 | while (it) { |
| 412 | struct cached_res *cache; |
| 413 | |
| 414 | cache = (struct cached_res*) pj_hash_this(resolver->hrescache, it); |
| 415 | pj_hash_set(NULL, resolver->hrescache, &cache->key, |
| 416 | sizeof(cache->key), 0, NULL); |
| 417 | pj_pool_release(cache->pool); |
| 418 | |
| 419 | it = pj_hash_first(resolver->hrescache, &it_buf); |
| 420 | } |
| 421 | |
| 422 | if (resolver->own_timer && resolver->timer) { |
| 423 | pj_timer_heap_destroy(resolver->timer); |
| 424 | resolver->timer = NULL; |
| 425 | } |
| 426 | |
| 427 | close_sock(resolver); |
| 428 | |
| 429 | if (resolver->own_ioqueue && resolver->ioqueue) { |
| 430 | pj_ioqueue_destroy(resolver->ioqueue); |
| 431 | resolver->ioqueue = NULL; |
| 432 | } |
| 433 | |
| 434 | if (resolver->mutex) { |
| 435 | pj_mutex_destroy(resolver->mutex); |
| 436 | resolver->mutex = NULL; |
| 437 | } |
| 438 | |
| 439 | if (resolver->pool) { |
| 440 | pj_pool_t *pool = resolver->pool; |
| 441 | resolver->pool = NULL; |
| 442 | pj_pool_release(pool); |
| 443 | } |
| 444 | return PJ_SUCCESS; |
| 445 | } |
| 446 | |
| 447 | |
| 448 | |
| 449 | /* |
| 450 | * Configure name servers for the DNS resolver. |
| 451 | */ |
| 452 | PJ_DEF(pj_status_t) pj_dns_resolver_set_ns( pj_dns_resolver *resolver, |
| 453 | unsigned count, |
| 454 | const pj_str_t servers[], |
| 455 | const pj_uint16_t ports[]) |
| 456 | { |
| 457 | unsigned i; |
| 458 | pj_time_val now; |
| 459 | pj_status_t status; |
| 460 | |
| 461 | PJ_ASSERT_RETURN(resolver && count && servers, PJ_EINVAL); |
| 462 | PJ_ASSERT_RETURN(count < PJ_DNS_RESOLVER_MAX_NS, PJ_EINVAL); |
| 463 | |
| 464 | pj_mutex_lock(resolver->mutex); |
| 465 | |
| 466 | if (count > PJ_DNS_RESOLVER_MAX_NS) |
| 467 | count = PJ_DNS_RESOLVER_MAX_NS; |
| 468 | |
| 469 | resolver->ns_count = 0; |
| 470 | pj_bzero(resolver->ns, sizeof(resolver->ns)); |
| 471 | |
| 472 | pj_gettimeofday(&now); |
| 473 | |
| 474 | for (i=0; i<count; ++i) { |
| 475 | struct nameserver *ns = &resolver->ns[i]; |
| 476 | |
| 477 | status = pj_sockaddr_in_init(&ns->addr, &servers[i], |
| 478 | (pj_uint16_t)(ports ? ports[i] : PORT)); |
| 479 | if (status != PJ_SUCCESS) { |
| 480 | pj_mutex_unlock(resolver->mutex); |
| 481 | return PJLIB_UTIL_EDNSINNSADDR; |
| 482 | } |
| 483 | |
| 484 | ns->state = STATE_ACTIVE; |
| 485 | ns->state_expiry = now; |
| 486 | ns->rt_delay.sec = 10; |
| 487 | } |
| 488 | |
| 489 | resolver->ns_count = count; |
| 490 | |
| 491 | pj_mutex_unlock(resolver->mutex); |
| 492 | return PJ_SUCCESS; |
| 493 | } |
| 494 | |
| 495 | |
| 496 | |
| 497 | /* |
| 498 | * Modify the resolver settings. |
| 499 | */ |
| 500 | PJ_DEF(pj_status_t) pj_dns_resolver_set_settings(pj_dns_resolver *resolver, |
| 501 | const pj_dns_settings *st) |
| 502 | { |
| 503 | PJ_ASSERT_RETURN(resolver && st, PJ_EINVAL); |
| 504 | |
| 505 | pj_mutex_lock(resolver->mutex); |
| 506 | pj_memcpy(&resolver->settings, st, sizeof(*st)); |
| 507 | pj_mutex_unlock(resolver->mutex); |
| 508 | return PJ_SUCCESS; |
| 509 | } |
| 510 | |
| 511 | |
| 512 | /* |
| 513 | * Get the resolver current settings. |
| 514 | */ |
| 515 | PJ_DEF(pj_status_t) pj_dns_resolver_get_settings( pj_dns_resolver *resolver, |
| 516 | pj_dns_settings *st) |
| 517 | { |
| 518 | PJ_ASSERT_RETURN(resolver && st, PJ_EINVAL); |
| 519 | |
| 520 | pj_mutex_lock(resolver->mutex); |
| 521 | pj_memcpy(st, &resolver->settings, sizeof(*st)); |
| 522 | pj_mutex_unlock(resolver->mutex); |
| 523 | return PJ_SUCCESS; |
| 524 | } |
| 525 | |
| 526 | |
| 527 | /* |
| 528 | * Poll for events from the resolver. |
| 529 | */ |
| 530 | PJ_DEF(void) pj_dns_resolver_handle_events(pj_dns_resolver *resolver, |
| 531 | const pj_time_val *timeout) |
| 532 | { |
| 533 | PJ_ASSERT_ON_FAIL(resolver, return); |
| 534 | |
| 535 | pj_mutex_lock(resolver->mutex); |
| 536 | pj_timer_heap_poll(resolver->timer, NULL); |
| 537 | pj_mutex_unlock(resolver->mutex); |
| 538 | |
| 539 | pj_ioqueue_poll(resolver->ioqueue, timeout); |
| 540 | } |
| 541 | |
| 542 | |
| 543 | /* Get one query node from the free node, if any, or allocate |
| 544 | * a new one. |
| 545 | */ |
| 546 | static pj_dns_async_query *alloc_qnode(pj_dns_resolver *resolver, |
| 547 | unsigned options, |
| 548 | void *user_data, |
| 549 | pj_dns_callback *cb) |
| 550 | { |
| 551 | pj_dns_async_query *q; |
| 552 | |
| 553 | /* Merge query options with resolver options */ |
| 554 | options |= resolver->settings.options; |
| 555 | |
| 556 | if (!pj_list_empty(&resolver->query_free_nodes)) { |
| 557 | q = resolver->query_free_nodes.next; |
| 558 | pj_list_erase(q); |
| 559 | pj_bzero(q, sizeof(*q)); |
| 560 | } else { |
| 561 | q = PJ_POOL_ZALLOC_T(resolver->pool, pj_dns_async_query); |
| 562 | } |
| 563 | |
| 564 | /* Init query */ |
| 565 | q->resolver = resolver; |
| 566 | q->options = options; |
| 567 | q->user_data = user_data; |
| 568 | q->cb = cb; |
| 569 | pj_list_init(&q->child_head); |
| 570 | |
| 571 | return q; |
| 572 | } |
| 573 | |
| 574 | |
| 575 | /* |
| 576 | * Transmit query. |
| 577 | */ |
| 578 | static pj_status_t transmit_query(pj_dns_resolver *resolver, |
| 579 | pj_dns_async_query *q) |
| 580 | { |
| 581 | unsigned pkt_size; |
| 582 | unsigned i, server_cnt; |
| 583 | unsigned servers[PJ_DNS_RESOLVER_MAX_NS]; |
| 584 | pj_time_val now; |
| 585 | pj_str_t name; |
| 586 | pj_time_val delay; |
| 587 | pj_status_t status; |
| 588 | |
| 589 | /* Select which nameserver(s) to send requests to. */ |
| 590 | server_cnt = PJ_ARRAY_SIZE(servers); |
| 591 | status = select_nameservers(resolver, &server_cnt, servers); |
| 592 | if (status != PJ_SUCCESS) { |
| 593 | return status; |
| 594 | } |
| 595 | |
| 596 | if (server_cnt == 0) { |
| 597 | return PJLIB_UTIL_EDNSNOWORKINGNS; |
| 598 | } |
| 599 | |
| 600 | /* Start retransmit/timeout timer for the query */ |
| 601 | pj_assert(q->timer_entry.id == 0); |
| 602 | q->timer_entry.id = 1; |
| 603 | q->timer_entry.user_data = q; |
| 604 | q->timer_entry.cb = &on_timeout; |
| 605 | |
| 606 | delay.sec = 0; |
| 607 | delay.msec = resolver->settings.qretr_delay; |
| 608 | pj_time_val_normalize(&delay); |
| 609 | status = pj_timer_heap_schedule(resolver->timer, &q->timer_entry, &delay); |
| 610 | if (status != PJ_SUCCESS) { |
| 611 | return status; |
| 612 | } |
| 613 | |
| 614 | /* Check if the socket is available for sending */ |
| 615 | if (pj_ioqueue_is_pending(resolver->udp_key, &resolver->udp_op_tx_key)) { |
| 616 | ++q->transmit_cnt; |
| 617 | PJ_LOG(4,(resolver->name.ptr, |
| 618 | "Socket busy in transmitting DNS %s query for %s%s", |
| 619 | pj_dns_get_type_name(q->key.qtype), |
| 620 | q->key.name, |
| 621 | (q->transmit_cnt < resolver->settings.qretr_count? |
| 622 | ", will try again later":""))); |
| 623 | return PJ_SUCCESS; |
| 624 | } |
| 625 | |
| 626 | /* Create DNS query packet */ |
| 627 | pkt_size = sizeof(resolver->udp_tx_pkt); |
| 628 | name = pj_str(q->key.name); |
| 629 | status = pj_dns_make_query(resolver->udp_tx_pkt, &pkt_size, |
| 630 | q->id, q->key.qtype, &name); |
| 631 | if (status != PJ_SUCCESS) { |
| 632 | pj_timer_heap_cancel(resolver->timer, &q->timer_entry); |
| 633 | return status; |
| 634 | } |
| 635 | |
| 636 | /* Get current time. */ |
| 637 | pj_gettimeofday(&now); |
| 638 | |
| 639 | /* Send the packet to name servers */ |
| 640 | for (i=0; i<server_cnt; ++i) { |
| 641 | pj_ssize_t sent = (pj_ssize_t) pkt_size; |
| 642 | struct nameserver *ns = &resolver->ns[servers[i]]; |
| 643 | |
| 644 | status = pj_ioqueue_sendto(resolver->udp_key, |
| 645 | &resolver->udp_op_tx_key, |
| 646 | resolver->udp_tx_pkt, &sent, 0, |
| 647 | &resolver->ns[servers[i]].addr, |
| 648 | sizeof(pj_sockaddr_in)); |
| 649 | |
| 650 | PJ_PERROR(4,(resolver->name.ptr, status, |
| 651 | "%s %d bytes to NS %d (%s:%d): DNS %s query for %s", |
| 652 | (q->transmit_cnt==0? "Transmitting":"Re-transmitting"), |
| 653 | (int)pkt_size, servers[i], |
| 654 | pj_inet_ntoa(ns->addr.sin_addr), |
| 655 | (int)pj_ntohs(ns->addr.sin_port), |
| 656 | pj_dns_get_type_name(q->key.qtype), |
| 657 | q->key.name)); |
| 658 | |
| 659 | if (ns->q_id == 0) { |
| 660 | ns->q_id = q->id; |
| 661 | ns->sent_time = now; |
| 662 | } |
| 663 | } |
| 664 | |
| 665 | ++q->transmit_cnt; |
| 666 | |
| 667 | return PJ_SUCCESS; |
| 668 | } |
| 669 | |
| 670 | |
| 671 | /* |
| 672 | * Initialize resource key for hash table lookup. |
| 673 | */ |
| 674 | static void init_res_key(struct res_key *key, int type, const pj_str_t *name) |
| 675 | { |
| 676 | unsigned i; |
| 677 | pj_size_t len; |
| 678 | char *dst = key->name; |
| 679 | const char *src = name->ptr; |
| 680 | |
| 681 | pj_bzero(key, sizeof(struct res_key)); |
| 682 | key->qtype = (pj_uint16_t)type; |
| 683 | |
| 684 | len = name->slen; |
| 685 | if (len > PJ_MAX_HOSTNAME) len = PJ_MAX_HOSTNAME; |
| 686 | |
| 687 | /* Copy key, in lowercase */ |
| 688 | for (i=0; i<len; ++i) { |
| 689 | *dst++ = (char)pj_tolower(*src++); |
| 690 | } |
| 691 | } |
| 692 | |
| 693 | |
| 694 | /* Allocate new cache entry */ |
| 695 | static struct cached_res *alloc_entry(pj_dns_resolver *resolver) |
| 696 | { |
| 697 | pj_pool_t *pool; |
| 698 | struct cached_res *cache; |
| 699 | |
| 700 | pool = pj_pool_create(resolver->pool->factory, "dnscache", |
| 701 | RES_BUF_SZ, 256, NULL); |
| 702 | cache = PJ_POOL_ZALLOC_T(pool, struct cached_res); |
| 703 | cache->pool = pool; |
| 704 | cache->ref_cnt = 1; |
| 705 | |
| 706 | return cache; |
| 707 | } |
| 708 | |
| 709 | /* Re-allocate cache entry, to free cached packet */ |
| 710 | static void reset_entry(struct cached_res **p_cached) |
| 711 | { |
| 712 | pj_pool_t *pool; |
| 713 | struct cached_res *cache = *p_cached; |
| 714 | unsigned ref_cnt; |
| 715 | |
| 716 | pool = cache->pool; |
| 717 | ref_cnt = cache->ref_cnt; |
| 718 | |
| 719 | pj_pool_reset(pool); |
| 720 | |
| 721 | cache = PJ_POOL_ZALLOC_T(pool, struct cached_res); |
| 722 | cache->pool = pool; |
| 723 | cache->ref_cnt = ref_cnt; |
| 724 | *p_cached = cache; |
| 725 | } |
| 726 | |
| 727 | /* Put unused/expired cached entry to the free list */ |
| 728 | static void free_entry(pj_dns_resolver *resolver, struct cached_res *cache) |
| 729 | { |
| 730 | PJ_UNUSED_ARG(resolver); |
| 731 | pj_pool_release(cache->pool); |
| 732 | } |
| 733 | |
| 734 | |
| 735 | /* |
| 736 | * Create and start asynchronous DNS query for a single resource. |
| 737 | */ |
| 738 | PJ_DEF(pj_status_t) pj_dns_resolver_start_query( pj_dns_resolver *resolver, |
| 739 | const pj_str_t *name, |
| 740 | int type, |
| 741 | unsigned options, |
| 742 | pj_dns_callback *cb, |
| 743 | void *user_data, |
| 744 | pj_dns_async_query **p_query) |
| 745 | { |
| 746 | pj_time_val now; |
| 747 | struct res_key key; |
| 748 | struct cached_res *cache; |
| 749 | pj_dns_async_query *q; |
| 750 | pj_uint32_t hval; |
| 751 | pj_status_t status = PJ_SUCCESS; |
| 752 | |
| 753 | /* Validate arguments */ |
| 754 | PJ_ASSERT_RETURN(resolver && name && type, PJ_EINVAL); |
| 755 | |
| 756 | /* Check name is not too long. */ |
| 757 | PJ_ASSERT_RETURN(name->slen>0 && name->slen < PJ_MAX_HOSTNAME, |
| 758 | PJ_ENAMETOOLONG); |
| 759 | |
| 760 | /* Check type */ |
| 761 | PJ_ASSERT_RETURN(type > 0 && type < 0xFFFF, PJ_EINVAL); |
| 762 | |
| 763 | if (p_query) |
| 764 | *p_query = NULL; |
| 765 | |
| 766 | /* Build resource key for looking up hash tables */ |
| 767 | init_res_key(&key, type, name); |
| 768 | |
| 769 | /* Start working with the resolver */ |
| 770 | pj_mutex_lock(resolver->mutex); |
| 771 | |
| 772 | /* Get current time. */ |
| 773 | pj_gettimeofday(&now); |
| 774 | |
| 775 | /* First, check if we have cached response for the specified name/type, |
| 776 | * and the cached entry has not expired. |
| 777 | */ |
| 778 | hval = 0; |
| 779 | cache = (struct cached_res *) pj_hash_get(resolver->hrescache, &key, |
| 780 | sizeof(key), &hval); |
| 781 | if (cache) { |
| 782 | /* We've found a cached entry. */ |
| 783 | |
| 784 | /* Check for expiration */ |
| 785 | if (PJ_TIME_VAL_GT(cache->expiry_time, now)) { |
| 786 | |
| 787 | /* Log */ |
| 788 | PJ_LOG(5,(resolver->name.ptr, |
| 789 | "Picked up DNS %s record for %.*s from cache, ttl=%d", |
| 790 | pj_dns_get_type_name(type), |
| 791 | (int)name->slen, name->ptr, |
| 792 | (int)(cache->expiry_time.sec - now.sec))); |
| 793 | |
| 794 | /* Map DNS Rcode in the response into PJLIB status name space */ |
| 795 | status = PJ_DNS_GET_RCODE(cache->pkt->hdr.flags); |
| 796 | status = PJ_STATUS_FROM_DNS_RCODE(status); |
| 797 | |
| 798 | /* Workaround for deadlock problem. Need to increment the cache's |
| 799 | * ref counter first before releasing mutex, so the cache won't be |
| 800 | * destroyed by other thread while in callback. |
| 801 | */ |
| 802 | cache->ref_cnt++; |
| 803 | pj_mutex_unlock(resolver->mutex); |
| 804 | |
| 805 | /* This cached response is still valid. Just return this |
| 806 | * response to caller. |
| 807 | */ |
| 808 | if (cb) { |
| 809 | (*cb)(user_data, status, cache->pkt); |
| 810 | } |
| 811 | |
| 812 | /* Done. No host resolution is necessary */ |
| 813 | pj_mutex_lock(resolver->mutex); |
| 814 | |
| 815 | /* Decrement the ref counter. Also check if it is time to free |
| 816 | * the cache (as it has been expired). |
| 817 | */ |
| 818 | cache->ref_cnt--; |
| 819 | if (cache->ref_cnt <= 0) |
| 820 | free_entry(resolver, cache); |
| 821 | |
| 822 | /* Must return PJ_SUCCESS */ |
| 823 | status = PJ_SUCCESS; |
| 824 | |
| 825 | goto on_return; |
| 826 | } |
| 827 | |
| 828 | /* At this point, we have a cached entry, but this entry has expired. |
| 829 | * Remove this entry from the cached list. |
| 830 | */ |
| 831 | pj_hash_set(NULL, resolver->hrescache, &key, sizeof(key), 0, NULL); |
| 832 | |
| 833 | /* Also free the cache, if it is not being used (by callback). */ |
| 834 | cache->ref_cnt--; |
| 835 | if (cache->ref_cnt <= 0) |
| 836 | free_entry(resolver, cache); |
| 837 | |
| 838 | /* Must continue with creating a query now */ |
| 839 | } |
| 840 | |
| 841 | /* Next, check if we have pending query on the same resource */ |
| 842 | q = (pj_dns_async_query *) pj_hash_get(resolver->hquerybyres, &key, |
| 843 | sizeof(key), NULL); |
| 844 | if (q) { |
| 845 | /* Yes, there's another pending query to the same key. |
| 846 | * Just create a new child query and add this query to |
| 847 | * pending query's child queries. |
| 848 | */ |
| 849 | pj_dns_async_query *nq; |
| 850 | |
| 851 | nq = alloc_qnode(resolver, options, user_data, cb); |
| 852 | pj_list_push_back(&q->child_head, nq); |
| 853 | |
| 854 | /* Done. This child query will be notified once the "parent" |
| 855 | * query completes. |
| 856 | */ |
| 857 | status = PJ_SUCCESS; |
| 858 | goto on_return; |
| 859 | } |
| 860 | |
| 861 | /* There's no pending query to the same key, initiate a new one. */ |
| 862 | q = alloc_qnode(resolver, options, user_data, cb); |
| 863 | |
| 864 | /* Save the ID and key */ |
| 865 | /* TODO: dnsext-forgery-resilient: randomize id for security */ |
| 866 | q->id = resolver->last_id++; |
| 867 | if (resolver->last_id == 0) |
| 868 | resolver->last_id = 1; |
| 869 | pj_memcpy(&q->key, &key, sizeof(struct res_key)); |
| 870 | |
| 871 | /* Send the query */ |
| 872 | status = transmit_query(resolver, q); |
| 873 | if (status != PJ_SUCCESS) { |
| 874 | pj_list_push_back(&resolver->query_free_nodes, q); |
| 875 | goto on_return; |
| 876 | } |
| 877 | |
| 878 | /* Add query entry to the hash tables */ |
| 879 | pj_hash_set_np(resolver->hquerybyid, &q->id, sizeof(q->id), |
| 880 | 0, q->hbufid, q); |
| 881 | pj_hash_set_np(resolver->hquerybyres, &q->key, sizeof(q->key), |
| 882 | 0, q->hbufkey, q); |
| 883 | |
| 884 | if (p_query) |
| 885 | *p_query = q; |
| 886 | |
| 887 | on_return: |
| 888 | pj_mutex_unlock(resolver->mutex); |
| 889 | return status; |
| 890 | } |
| 891 | |
| 892 | |
| 893 | /* |
| 894 | * Cancel a pending query. |
| 895 | */ |
| 896 | PJ_DEF(pj_status_t) pj_dns_resolver_cancel_query(pj_dns_async_query *query, |
| 897 | pj_bool_t notify) |
| 898 | { |
| 899 | pj_dns_callback *cb; |
| 900 | |
| 901 | PJ_ASSERT_RETURN(query, PJ_EINVAL); |
| 902 | |
| 903 | pj_mutex_lock(query->resolver->mutex); |
| 904 | |
| 905 | cb = query->cb; |
| 906 | query->cb = NULL; |
| 907 | |
| 908 | if (notify) |
| 909 | (*cb)(query->user_data, PJ_ECANCELLED, NULL); |
| 910 | |
| 911 | pj_mutex_unlock(query->resolver->mutex); |
| 912 | return PJ_SUCCESS; |
| 913 | } |
| 914 | |
| 915 | |
| 916 | /* |
| 917 | * DNS response containing A packet. |
| 918 | */ |
| 919 | PJ_DEF(pj_status_t) pj_dns_parse_a_response(const pj_dns_parsed_packet *pkt, |
| 920 | pj_dns_a_record *rec) |
| 921 | { |
| 922 | enum { MAX_SEARCH = 20 }; |
| 923 | pj_str_t hostname, alias = {NULL, 0}, *resname; |
| 924 | pj_size_t bufstart = 0; |
| 925 | pj_size_t bufleft = sizeof(rec->buf_); |
| 926 | unsigned i, ansidx, search_cnt=0; |
| 927 | |
| 928 | PJ_ASSERT_RETURN(pkt && rec, PJ_EINVAL); |
| 929 | |
| 930 | /* Init the record */ |
| 931 | pj_bzero(rec, sizeof(pj_dns_a_record)); |
| 932 | |
| 933 | /* Return error if there's error in the packet. */ |
| 934 | if (PJ_DNS_GET_RCODE(pkt->hdr.flags)) |
| 935 | return PJ_STATUS_FROM_DNS_RCODE(PJ_DNS_GET_RCODE(pkt->hdr.flags)); |
| 936 | |
| 937 | /* Return error if there's no query section */ |
| 938 | if (pkt->hdr.qdcount == 0) |
| 939 | return PJLIB_UTIL_EDNSINANSWER; |
| 940 | |
| 941 | /* Return error if there's no answer */ |
| 942 | if (pkt->hdr.anscount == 0) |
| 943 | return PJLIB_UTIL_EDNSNOANSWERREC; |
| 944 | |
| 945 | /* Get the hostname from the query. */ |
| 946 | hostname = pkt->q[0].name; |
| 947 | |
| 948 | /* Copy hostname to the record */ |
| 949 | if (hostname.slen > (int)bufleft) { |
| 950 | return PJ_ENAMETOOLONG; |
| 951 | } |
| 952 | |
| 953 | pj_memcpy(&rec->buf_[bufstart], hostname.ptr, hostname.slen); |
| 954 | rec->name.ptr = &rec->buf_[bufstart]; |
| 955 | rec->name.slen = hostname.slen; |
| 956 | |
| 957 | bufstart += hostname.slen; |
| 958 | bufleft -= hostname.slen; |
| 959 | |
| 960 | /* Find the first RR which name matches the hostname */ |
| 961 | for (ansidx=0; ansidx < pkt->hdr.anscount; ++ansidx) { |
| 962 | if (pj_stricmp(&pkt->ans[ansidx].name, &hostname)==0) |
| 963 | break; |
| 964 | } |
| 965 | |
| 966 | if (ansidx == pkt->hdr.anscount) |
| 967 | return PJLIB_UTIL_EDNSNOANSWERREC; |
| 968 | |
| 969 | resname = &hostname; |
| 970 | |
| 971 | /* Keep following CNAME records. */ |
| 972 | while (pkt->ans[ansidx].type == PJ_DNS_TYPE_CNAME && |
| 973 | search_cnt++ < MAX_SEARCH) |
| 974 | { |
| 975 | resname = &pkt->ans[ansidx].rdata.cname.name; |
| 976 | |
| 977 | if (!alias.slen) |
| 978 | alias = *resname; |
| 979 | |
| 980 | for (i=0; i < pkt->hdr.anscount; ++i) { |
| 981 | if (pj_stricmp(resname, &pkt->ans[i].name)==0) { |
| 982 | break; |
| 983 | } |
| 984 | } |
| 985 | |
| 986 | if (i==pkt->hdr.anscount) |
| 987 | return PJLIB_UTIL_EDNSNOANSWERREC; |
| 988 | |
| 989 | ansidx = i; |
| 990 | } |
| 991 | |
| 992 | if (search_cnt >= MAX_SEARCH) |
| 993 | return PJLIB_UTIL_EDNSINANSWER; |
| 994 | |
| 995 | if (pkt->ans[ansidx].type != PJ_DNS_TYPE_A) |
| 996 | return PJLIB_UTIL_EDNSINANSWER; |
| 997 | |
| 998 | /* Copy alias to the record, if present. */ |
| 999 | if (alias.slen) { |
| 1000 | if (alias.slen > (int)bufleft) |
| 1001 | return PJ_ENAMETOOLONG; |
| 1002 | |
| 1003 | pj_memcpy(&rec->buf_[bufstart], alias.ptr, alias.slen); |
| 1004 | rec->alias.ptr = &rec->buf_[bufstart]; |
| 1005 | rec->alias.slen = alias.slen; |
| 1006 | |
| 1007 | bufstart += alias.slen; |
| 1008 | bufleft -= alias.slen; |
| 1009 | } |
| 1010 | |
| 1011 | /* Get the IP addresses. */ |
| 1012 | for (i=0; i < pkt->hdr.anscount; ++i) { |
| 1013 | if (pkt->ans[i].type == PJ_DNS_TYPE_A && |
| 1014 | pj_stricmp(&pkt->ans[i].name, resname)==0 && |
| 1015 | rec->addr_count < PJ_DNS_MAX_IP_IN_A_REC) |
| 1016 | { |
| 1017 | rec->addr[rec->addr_count++].s_addr = |
| 1018 | pkt->ans[i].rdata.a.ip_addr.s_addr; |
| 1019 | } |
| 1020 | } |
| 1021 | |
| 1022 | if (rec->addr_count == 0) |
| 1023 | return PJLIB_UTIL_EDNSNOANSWERREC; |
| 1024 | |
| 1025 | return PJ_SUCCESS; |
| 1026 | } |
| 1027 | |
| 1028 | |
| 1029 | /* Set nameserver state */ |
| 1030 | static void set_nameserver_state(pj_dns_resolver *resolver, |
| 1031 | unsigned index, |
| 1032 | enum ns_state state, |
| 1033 | const pj_time_val *now) |
| 1034 | { |
| 1035 | struct nameserver *ns = &resolver->ns[index]; |
| 1036 | enum ns_state old_state = ns->state; |
| 1037 | |
| 1038 | ns->state = state; |
| 1039 | ns->state_expiry = *now; |
| 1040 | |
| 1041 | if (state == STATE_PROBING) |
| 1042 | ns->state_expiry.sec += ((resolver->settings.qretr_count + 2) * |
| 1043 | resolver->settings.qretr_delay) / 1000; |
| 1044 | else if (state == STATE_ACTIVE) |
| 1045 | ns->state_expiry.sec += resolver->settings.good_ns_ttl; |
| 1046 | else |
| 1047 | ns->state_expiry.sec += resolver->settings.bad_ns_ttl; |
| 1048 | |
| 1049 | PJ_LOG(5, (resolver->name.ptr, "Nameserver %s:%d state changed %s --> %s", |
| 1050 | pj_inet_ntoa(ns->addr.sin_addr), |
| 1051 | (int)pj_ntohs(ns->addr.sin_port), |
| 1052 | state_names[old_state], state_names[state])); |
| 1053 | } |
| 1054 | |
| 1055 | |
| 1056 | /* Select which nameserver(s) to use. Note this may return multiple |
| 1057 | * name servers. The algorithm to select which nameservers to be |
| 1058 | * sent the request to is as follows: |
| 1059 | * - select the first nameserver that is known to be good for the |
| 1060 | * last PJ_DNS_RESOLVER_GOOD_NS_TTL interval. |
| 1061 | * - for all NSes, if last_known_good >= PJ_DNS_RESOLVER_GOOD_NS_TTL, |
| 1062 | * include the NS to re-check again that the server is still good, |
| 1063 | * unless the NS is known to be bad in the last PJ_DNS_RESOLVER_BAD_NS_TTL |
| 1064 | * interval. |
| 1065 | * - for all NSes, if last_known_bad >= PJ_DNS_RESOLVER_BAD_NS_TTL, |
| 1066 | * also include the NS to re-check again that the server is still bad. |
| 1067 | */ |
| 1068 | static pj_status_t select_nameservers(pj_dns_resolver *resolver, |
| 1069 | unsigned *count, |
| 1070 | unsigned servers[]) |
| 1071 | { |
| 1072 | unsigned i, max_count=*count; |
| 1073 | int min; |
| 1074 | pj_time_val now; |
| 1075 | |
| 1076 | pj_assert(max_count > 0); |
| 1077 | |
| 1078 | *count = 0; |
| 1079 | servers[0] = 0xFFFF; |
| 1080 | |
| 1081 | /* Check that nameservers are configured. */ |
| 1082 | if (resolver->ns_count == 0) |
| 1083 | return PJLIB_UTIL_EDNSNONS; |
| 1084 | |
| 1085 | pj_gettimeofday(&now); |
| 1086 | |
| 1087 | /* Select one Active nameserver with best response time. */ |
| 1088 | for (min=-1, i=0; i<resolver->ns_count; ++i) { |
| 1089 | struct nameserver *ns = &resolver->ns[i]; |
| 1090 | |
| 1091 | if (ns->state != STATE_ACTIVE) |
| 1092 | continue; |
| 1093 | |
| 1094 | if (min == -1) |
| 1095 | min = i; |
| 1096 | else if (PJ_TIME_VAL_LT(ns->rt_delay, resolver->ns[min].rt_delay)) |
| 1097 | min = i; |
| 1098 | } |
| 1099 | if (min != -1) { |
| 1100 | servers[0] = min; |
| 1101 | ++(*count); |
| 1102 | } |
| 1103 | |
| 1104 | /* Scan nameservers. */ |
| 1105 | for (i=0; i<resolver->ns_count && *count < max_count; ++i) { |
| 1106 | struct nameserver *ns = &resolver->ns[i]; |
| 1107 | |
| 1108 | if (PJ_TIME_VAL_LTE(ns->state_expiry, now)) { |
| 1109 | if (ns->state == STATE_PROBING) { |
| 1110 | set_nameserver_state(resolver, i, STATE_BAD, &now); |
| 1111 | } else { |
| 1112 | set_nameserver_state(resolver, i, STATE_PROBING, &now); |
| 1113 | if ((int)i != min) { |
| 1114 | servers[*count] = i; |
| 1115 | ++(*count); |
| 1116 | } |
| 1117 | } |
| 1118 | } else if (ns->state == STATE_PROBING && (int)i != min) { |
| 1119 | servers[*count] = i; |
| 1120 | ++(*count); |
| 1121 | } |
| 1122 | } |
| 1123 | |
| 1124 | return PJ_SUCCESS; |
| 1125 | } |
| 1126 | |
| 1127 | |
| 1128 | /* Update name server status */ |
| 1129 | static void report_nameserver_status(pj_dns_resolver *resolver, |
| 1130 | const pj_sockaddr_in *ns_addr, |
| 1131 | const pj_dns_parsed_packet *pkt) |
| 1132 | { |
| 1133 | unsigned i; |
| 1134 | int rcode; |
| 1135 | pj_uint32_t q_id; |
| 1136 | pj_time_val now; |
| 1137 | pj_bool_t is_good; |
| 1138 | |
| 1139 | /* Only mark nameserver as "bad" if it returned non-parseable response or |
| 1140 | * it returned the following status codes |
| 1141 | */ |
| 1142 | if (pkt) { |
| 1143 | rcode = PJ_DNS_GET_RCODE(pkt->hdr.flags); |
| 1144 | q_id = pkt->hdr.id; |
| 1145 | } else { |
| 1146 | rcode = 0; |
| 1147 | q_id = (pj_uint32_t)-1; |
| 1148 | } |
| 1149 | |
| 1150 | if (!pkt || rcode == PJ_DNS_RCODE_SERVFAIL || |
| 1151 | rcode == PJ_DNS_RCODE_REFUSED || |
| 1152 | rcode == PJ_DNS_RCODE_NOTAUTH) |
| 1153 | { |
| 1154 | is_good = PJ_FALSE; |
| 1155 | } else { |
| 1156 | is_good = PJ_TRUE; |
| 1157 | } |
| 1158 | |
| 1159 | |
| 1160 | /* Mark time */ |
| 1161 | pj_gettimeofday(&now); |
| 1162 | |
| 1163 | /* Recheck all nameservers. */ |
| 1164 | for (i=0; i<resolver->ns_count; ++i) { |
| 1165 | struct nameserver *ns = &resolver->ns[i]; |
| 1166 | |
| 1167 | if (ns->addr.sin_addr.s_addr == ns_addr->sin_addr.s_addr && |
| 1168 | ns->addr.sin_port == ns_addr->sin_port && |
| 1169 | ns->addr.sin_family == ns_addr->sin_family) |
| 1170 | { |
| 1171 | if (q_id == ns->q_id) { |
| 1172 | /* Calculate response time */ |
| 1173 | pj_time_val rt = now; |
| 1174 | PJ_TIME_VAL_SUB(rt, ns->sent_time); |
| 1175 | ns->rt_delay = rt; |
| 1176 | ns->q_id = 0; |
| 1177 | } |
| 1178 | set_nameserver_state(resolver, i, |
| 1179 | (is_good ? STATE_ACTIVE : STATE_BAD), &now); |
| 1180 | break; |
| 1181 | } |
| 1182 | } |
| 1183 | } |
| 1184 | |
| 1185 | |
| 1186 | /* Update response cache */ |
| 1187 | static void update_res_cache(pj_dns_resolver *resolver, |
| 1188 | const struct res_key *key, |
| 1189 | pj_status_t status, |
| 1190 | pj_bool_t set_expiry, |
| 1191 | const pj_dns_parsed_packet *pkt) |
| 1192 | { |
| 1193 | struct cached_res *cache; |
| 1194 | pj_uint32_t hval=0, ttl; |
| 1195 | |
| 1196 | /* If status is unsuccessful, clear the same entry from the cache */ |
| 1197 | if (status != PJ_SUCCESS) { |
| 1198 | cache = (struct cached_res *) pj_hash_get(resolver->hrescache, key, |
| 1199 | sizeof(*key), &hval); |
| 1200 | if (cache && --cache->ref_cnt <= 0) |
| 1201 | free_entry(resolver, cache); |
| 1202 | pj_hash_set(NULL, resolver->hrescache, key, sizeof(*key), hval, NULL); |
| 1203 | } |
| 1204 | |
| 1205 | |
| 1206 | /* Calculate expiration time. */ |
| 1207 | if (set_expiry) { |
| 1208 | if (pkt->hdr.anscount == 0 || status != PJ_SUCCESS) { |
| 1209 | /* If we don't have answers for the name, then give a different |
| 1210 | * ttl value (note: PJ_DNS_RESOLVER_INVALID_TTL may be zero, |
| 1211 | * which means that invalid names won't be kept in the cache) |
| 1212 | */ |
| 1213 | ttl = PJ_DNS_RESOLVER_INVALID_TTL; |
| 1214 | |
| 1215 | } else { |
| 1216 | /* Otherwise get the minimum TTL from the answers */ |
| 1217 | unsigned i; |
| 1218 | ttl = 0xFFFFFFFF; |
| 1219 | for (i=0; i<pkt->hdr.anscount; ++i) { |
| 1220 | if (pkt->ans[i].ttl < ttl) |
| 1221 | ttl = pkt->ans[i].ttl; |
| 1222 | } |
| 1223 | } |
| 1224 | } else { |
| 1225 | ttl = 0xFFFFFFFF; |
| 1226 | } |
| 1227 | |
| 1228 | /* Apply maximum TTL */ |
| 1229 | if (ttl > resolver->settings.cache_max_ttl) |
| 1230 | ttl = resolver->settings.cache_max_ttl; |
| 1231 | |
| 1232 | /* If TTL is zero, clear the same entry in the hash table */ |
| 1233 | if (ttl == 0) { |
| 1234 | cache = (struct cached_res *) pj_hash_get(resolver->hrescache, key, |
| 1235 | sizeof(*key), &hval); |
| 1236 | if (cache && --cache->ref_cnt <= 0) |
| 1237 | free_entry(resolver, cache); |
| 1238 | pj_hash_set(NULL, resolver->hrescache, key, sizeof(*key), hval, NULL); |
| 1239 | return; |
| 1240 | } |
| 1241 | |
| 1242 | /* Get a cache response entry */ |
| 1243 | cache = (struct cached_res *) pj_hash_get(resolver->hrescache, key, |
| 1244 | sizeof(*key), &hval); |
| 1245 | if (cache == NULL) { |
| 1246 | cache = alloc_entry(resolver); |
| 1247 | } else if (cache->ref_cnt > 1) { |
| 1248 | /* When cache entry is being used by callback (to app), just decrement |
| 1249 | * ref_cnt so it will be freed after the callback returns and allocate |
| 1250 | * new entry. |
| 1251 | */ |
| 1252 | cache->ref_cnt--; |
| 1253 | cache = alloc_entry(resolver); |
| 1254 | } else { |
| 1255 | /* Reset cache to avoid bloated cache pool */ |
| 1256 | reset_entry(&cache); |
| 1257 | } |
| 1258 | |
| 1259 | /* Duplicate the packet. |
| 1260 | * We don't need to keep the NS and AR sections from the packet, |
| 1261 | * so exclude from duplication. We do need to keep the Query |
| 1262 | * section since DNS A parser needs the query section to know |
| 1263 | * the name being requested. |
| 1264 | */ |
| 1265 | pj_dns_packet_dup(cache->pool, pkt, |
| 1266 | PJ_DNS_NO_NS | PJ_DNS_NO_AR, |
| 1267 | &cache->pkt); |
| 1268 | |
| 1269 | /* Calculate expiration time */ |
| 1270 | if (set_expiry) { |
| 1271 | pj_gettimeofday(&cache->expiry_time); |
| 1272 | cache->expiry_time.sec += ttl; |
| 1273 | } else { |
| 1274 | cache->expiry_time.sec = 0x7FFFFFFFL; |
| 1275 | cache->expiry_time.msec = 0; |
| 1276 | } |
| 1277 | |
| 1278 | /* Copy key to the cached response */ |
| 1279 | pj_memcpy(&cache->key, key, sizeof(*key)); |
| 1280 | |
| 1281 | /* Update the hash table */ |
| 1282 | pj_hash_set_np(resolver->hrescache, &cache->key, sizeof(*key), hval, |
| 1283 | cache->hbuf, cache); |
| 1284 | |
| 1285 | } |
| 1286 | |
| 1287 | |
| 1288 | /* Callback to be called when query has timed out */ |
| 1289 | static void on_timeout( pj_timer_heap_t *timer_heap, |
| 1290 | struct pj_timer_entry *entry) |
| 1291 | { |
| 1292 | pj_dns_resolver *resolver; |
| 1293 | pj_dns_async_query *q, *cq; |
| 1294 | pj_status_t status; |
| 1295 | |
| 1296 | PJ_UNUSED_ARG(timer_heap); |
| 1297 | |
| 1298 | q = (pj_dns_async_query *) entry->user_data; |
| 1299 | resolver = q->resolver; |
| 1300 | |
| 1301 | pj_mutex_lock(resolver->mutex); |
| 1302 | |
| 1303 | /* Recheck that this query is still pending, since there is a slight |
| 1304 | * possibility of race condition (timer elapsed while at the same time |
| 1305 | * response arrives) |
| 1306 | */ |
| 1307 | if (pj_hash_get(resolver->hquerybyid, &q->id, sizeof(q->id), NULL)==NULL) { |
| 1308 | /* Yeah, this query is done. */ |
| 1309 | pj_mutex_unlock(resolver->mutex); |
| 1310 | return; |
| 1311 | } |
| 1312 | |
| 1313 | /* Invalidate id. */ |
| 1314 | q->timer_entry.id = 0; |
| 1315 | |
| 1316 | /* Check to see if we should retransmit instead of time out */ |
| 1317 | if (q->transmit_cnt < resolver->settings.qretr_count) { |
| 1318 | status = transmit_query(resolver, q); |
| 1319 | if (status == PJ_SUCCESS) { |
| 1320 | pj_mutex_unlock(resolver->mutex); |
| 1321 | return; |
| 1322 | } else { |
| 1323 | /* Error occurs */ |
| 1324 | char errmsg[PJ_ERR_MSG_SIZE]; |
| 1325 | |
| 1326 | pj_strerror(status, errmsg, sizeof(errmsg)); |
| 1327 | PJ_LOG(4,(resolver->name.ptr, |
| 1328 | "Error transmitting request: %s", errmsg)); |
| 1329 | |
| 1330 | /* Let it fallback to timeout section below */ |
| 1331 | } |
| 1332 | } |
| 1333 | |
| 1334 | /* Clear hash table entries */ |
| 1335 | pj_hash_set(NULL, resolver->hquerybyid, &q->id, sizeof(q->id), 0, NULL); |
| 1336 | pj_hash_set(NULL, resolver->hquerybyres, &q->key, sizeof(q->key), 0, NULL); |
| 1337 | |
| 1338 | /* Workaround for deadlock problem in #1565 (similar to #1108) */ |
| 1339 | pj_mutex_unlock(resolver->mutex); |
| 1340 | |
| 1341 | /* Call application callback, if any. */ |
| 1342 | if (q->cb) |
| 1343 | (*q->cb)(q->user_data, PJ_ETIMEDOUT, NULL); |
| 1344 | |
| 1345 | /* Call application callback for child queries. */ |
| 1346 | cq = q->child_head.next; |
| 1347 | while (cq != (void*)&q->child_head) { |
| 1348 | if (cq->cb) |
| 1349 | (*cq->cb)(cq->user_data, PJ_ETIMEDOUT, NULL); |
| 1350 | cq = cq->next; |
| 1351 | } |
| 1352 | |
| 1353 | /* Workaround for deadlock problem in #1565 (similar to #1108) */ |
| 1354 | pj_mutex_lock(resolver->mutex); |
| 1355 | |
| 1356 | /* Clear data */ |
| 1357 | q->timer_entry.id = 0; |
| 1358 | q->user_data = NULL; |
| 1359 | |
| 1360 | /* Put child entries into recycle list */ |
| 1361 | cq = q->child_head.next; |
| 1362 | while (cq != (void*)&q->child_head) { |
| 1363 | pj_dns_async_query *next = cq->next; |
| 1364 | pj_list_push_back(&resolver->query_free_nodes, cq); |
| 1365 | cq = next; |
| 1366 | } |
| 1367 | |
| 1368 | /* Put query entry into recycle list */ |
| 1369 | pj_list_push_back(&resolver->query_free_nodes, q); |
| 1370 | |
| 1371 | pj_mutex_unlock(resolver->mutex); |
| 1372 | } |
| 1373 | |
| 1374 | |
| 1375 | /* Callback from ioqueue when packet is received */ |
| 1376 | static void on_read_complete(pj_ioqueue_key_t *key, |
| 1377 | pj_ioqueue_op_key_t *op_key, |
| 1378 | pj_ssize_t bytes_read) |
| 1379 | { |
| 1380 | pj_dns_resolver *resolver; |
| 1381 | pj_pool_t *pool = NULL; |
| 1382 | pj_dns_parsed_packet *dns_pkt; |
| 1383 | pj_dns_async_query *q; |
| 1384 | pj_status_t status; |
| 1385 | PJ_USE_EXCEPTION; |
| 1386 | |
| 1387 | |
| 1388 | resolver = (pj_dns_resolver *) pj_ioqueue_get_user_data(key); |
| 1389 | pj_mutex_lock(resolver->mutex); |
| 1390 | |
| 1391 | |
| 1392 | /* Check for errors */ |
| 1393 | if (bytes_read < 0) { |
| 1394 | char errmsg[PJ_ERR_MSG_SIZE]; |
| 1395 | |
| 1396 | status = (pj_status_t)-bytes_read; |
| 1397 | pj_strerror(status, errmsg, sizeof(errmsg)); |
| 1398 | PJ_LOG(4,(resolver->name.ptr, |
| 1399 | "DNS resolver read error from %s:%d: %s", |
| 1400 | pj_inet_ntoa(resolver->udp_src_addr.sin_addr), |
| 1401 | pj_ntohs(resolver->udp_src_addr.sin_port), |
| 1402 | errmsg)); |
| 1403 | |
| 1404 | goto read_next_packet; |
| 1405 | } |
| 1406 | |
| 1407 | PJ_LOG(5,(resolver->name.ptr, |
| 1408 | "Received %d bytes DNS response from %s:%d", |
| 1409 | (int)bytes_read, |
| 1410 | pj_inet_ntoa(resolver->udp_src_addr.sin_addr), |
| 1411 | pj_ntohs(resolver->udp_src_addr.sin_port))); |
| 1412 | |
| 1413 | |
| 1414 | /* Check for zero packet */ |
| 1415 | if (bytes_read == 0) |
| 1416 | goto read_next_packet; |
| 1417 | |
| 1418 | /* Create temporary pool from a fixed buffer */ |
| 1419 | pool = pj_pool_create_on_buf("restmp", resolver->tmp_pool, |
| 1420 | sizeof(resolver->tmp_pool)); |
| 1421 | |
| 1422 | /* Parse DNS response */ |
| 1423 | status = -1; |
| 1424 | dns_pkt = NULL; |
| 1425 | PJ_TRY { |
| 1426 | status = pj_dns_parse_packet(pool, resolver->udp_rx_pkt, |
| 1427 | (unsigned)bytes_read, &dns_pkt); |
| 1428 | } |
| 1429 | PJ_CATCH_ANY { |
| 1430 | status = PJ_ENOMEM; |
| 1431 | } |
| 1432 | PJ_END; |
| 1433 | |
| 1434 | /* Update nameserver status */ |
| 1435 | report_nameserver_status(resolver, &resolver->udp_src_addr, dns_pkt); |
| 1436 | |
| 1437 | /* Handle parse error */ |
| 1438 | if (status != PJ_SUCCESS) { |
| 1439 | char errmsg[PJ_ERR_MSG_SIZE]; |
| 1440 | |
| 1441 | pj_strerror(status, errmsg, sizeof(errmsg)); |
| 1442 | PJ_LOG(3,(resolver->name.ptr, |
| 1443 | "Error parsing DNS response from %s:%d: %s", |
| 1444 | pj_inet_ntoa(resolver->udp_src_addr.sin_addr), |
| 1445 | pj_ntohs(resolver->udp_src_addr.sin_port), |
| 1446 | errmsg)); |
| 1447 | goto read_next_packet; |
| 1448 | } |
| 1449 | |
| 1450 | /* Find the query based on the transaction ID */ |
| 1451 | q = (pj_dns_async_query*) |
| 1452 | pj_hash_get(resolver->hquerybyid, &dns_pkt->hdr.id, |
| 1453 | sizeof(dns_pkt->hdr.id), NULL); |
| 1454 | if (!q) { |
| 1455 | PJ_LOG(5,(resolver->name.ptr, |
| 1456 | "DNS response from %s:%d id=%d discarded", |
| 1457 | pj_inet_ntoa(resolver->udp_src_addr.sin_addr), |
| 1458 | pj_ntohs(resolver->udp_src_addr.sin_port), |
| 1459 | (unsigned)dns_pkt->hdr.id)); |
| 1460 | goto read_next_packet; |
| 1461 | } |
| 1462 | |
| 1463 | /* Map DNS Rcode in the response into PJLIB status name space */ |
| 1464 | status = PJ_STATUS_FROM_DNS_RCODE(PJ_DNS_GET_RCODE(dns_pkt->hdr.flags)); |
| 1465 | |
| 1466 | /* Cancel query timeout timer. */ |
| 1467 | pj_assert(q->timer_entry.id != 0); |
| 1468 | pj_timer_heap_cancel(resolver->timer, &q->timer_entry); |
| 1469 | q->timer_entry.id = 0; |
| 1470 | |
| 1471 | /* Clear hash table entries */ |
| 1472 | pj_hash_set(NULL, resolver->hquerybyid, &q->id, sizeof(q->id), 0, NULL); |
| 1473 | pj_hash_set(NULL, resolver->hquerybyres, &q->key, sizeof(q->key), 0, NULL); |
| 1474 | |
| 1475 | /* Workaround for deadlock problem in #1108 */ |
| 1476 | pj_mutex_unlock(resolver->mutex); |
| 1477 | |
| 1478 | /* Notify applications first, to allow application to modify the |
| 1479 | * record before it is saved to the hash table. |
| 1480 | */ |
| 1481 | if (q->cb) |
| 1482 | (*q->cb)(q->user_data, status, dns_pkt); |
| 1483 | |
| 1484 | /* If query has subqueries, notify subqueries's application callback */ |
| 1485 | if (!pj_list_empty(&q->child_head)) { |
| 1486 | pj_dns_async_query *child_q; |
| 1487 | |
| 1488 | child_q = q->child_head.next; |
| 1489 | while (child_q != (pj_dns_async_query*)&q->child_head) { |
| 1490 | if (child_q->cb) |
| 1491 | (*child_q->cb)(child_q->user_data, status, dns_pkt); |
| 1492 | child_q = child_q->next; |
| 1493 | } |
| 1494 | } |
| 1495 | |
| 1496 | /* Workaround for deadlock problem in #1108 */ |
| 1497 | pj_mutex_lock(resolver->mutex); |
| 1498 | |
| 1499 | /* Save/update response cache. */ |
| 1500 | update_res_cache(resolver, &q->key, status, PJ_TRUE, dns_pkt); |
| 1501 | |
| 1502 | /* Recycle query objects, starting with the child queries */ |
| 1503 | if (!pj_list_empty(&q->child_head)) { |
| 1504 | pj_dns_async_query *child_q; |
| 1505 | |
| 1506 | child_q = q->child_head.next; |
| 1507 | while (child_q != (pj_dns_async_query*)&q->child_head) { |
| 1508 | pj_dns_async_query *next = child_q->next; |
| 1509 | pj_list_erase(child_q); |
| 1510 | pj_list_push_back(&resolver->query_free_nodes, child_q); |
| 1511 | child_q = next; |
| 1512 | } |
| 1513 | } |
| 1514 | pj_list_push_back(&resolver->query_free_nodes, q); |
| 1515 | |
| 1516 | read_next_packet: |
| 1517 | if (pool) { |
| 1518 | /* needed just in case PJ_HAS_POOL_ALT_API is set */ |
| 1519 | pj_pool_release(pool); |
| 1520 | } |
| 1521 | bytes_read = sizeof(resolver->udp_rx_pkt); |
| 1522 | resolver->udp_addr_len = sizeof(resolver->udp_src_addr); |
| 1523 | status = pj_ioqueue_recvfrom(resolver->udp_key, op_key, |
| 1524 | resolver->udp_rx_pkt, |
| 1525 | &bytes_read, PJ_IOQUEUE_ALWAYS_ASYNC, |
| 1526 | &resolver->udp_src_addr, |
| 1527 | &resolver->udp_addr_len); |
| 1528 | if (status != PJ_EPENDING) { |
| 1529 | char errmsg[PJ_ERR_MSG_SIZE]; |
| 1530 | |
| 1531 | pj_strerror(status, errmsg, sizeof(errmsg)); |
| 1532 | PJ_LOG(4,(resolver->name.ptr, "DNS resolver ioqueue read error: %s", |
| 1533 | errmsg)); |
| 1534 | |
| 1535 | pj_assert(!"Unhandled error"); |
| 1536 | } |
| 1537 | |
| 1538 | pj_mutex_unlock(resolver->mutex); |
| 1539 | } |
| 1540 | |
| 1541 | |
| 1542 | /* |
| 1543 | * Put the specified DNS packet into DNS cache. This function is mainly used |
| 1544 | * for testing the resolver, however it can also be used to inject entries |
| 1545 | * into the resolver. |
| 1546 | */ |
| 1547 | PJ_DEF(pj_status_t) pj_dns_resolver_add_entry( pj_dns_resolver *resolver, |
| 1548 | const pj_dns_parsed_packet *pkt, |
| 1549 | pj_bool_t set_ttl) |
| 1550 | { |
| 1551 | struct res_key key; |
| 1552 | |
| 1553 | /* Sanity check */ |
| 1554 | PJ_ASSERT_RETURN(resolver && pkt, PJ_EINVAL); |
| 1555 | |
| 1556 | /* Packet must be a DNS response */ |
| 1557 | PJ_ASSERT_RETURN(PJ_DNS_GET_QR(pkt->hdr.flags) & 1, PJ_EINVAL); |
| 1558 | |
| 1559 | /* Make sure there are answers in the packet */ |
| 1560 | PJ_ASSERT_RETURN((pkt->hdr.anscount && pkt->ans) || |
| 1561 | (pkt->hdr.qdcount && pkt->q), |
| 1562 | PJLIB_UTIL_EDNSNOANSWERREC); |
| 1563 | |
| 1564 | pj_mutex_lock(resolver->mutex); |
| 1565 | |
| 1566 | /* Build resource key for looking up hash tables */ |
| 1567 | pj_bzero(&key, sizeof(struct res_key)); |
| 1568 | if (pkt->hdr.anscount) { |
| 1569 | /* Make sure name is not too long. */ |
| 1570 | PJ_ASSERT_RETURN(pkt->ans[0].name.slen < PJ_MAX_HOSTNAME, |
| 1571 | PJ_ENAMETOOLONG); |
| 1572 | |
| 1573 | init_res_key(&key, pkt->ans[0].type, &pkt->ans[0].name); |
| 1574 | |
| 1575 | } else { |
| 1576 | /* Make sure name is not too long. */ |
| 1577 | PJ_ASSERT_RETURN(pkt->q[0].name.slen < PJ_MAX_HOSTNAME, |
| 1578 | PJ_ENAMETOOLONG); |
| 1579 | |
| 1580 | init_res_key(&key, pkt->q[0].type, &pkt->q[0].name); |
| 1581 | } |
| 1582 | |
| 1583 | /* Insert entry. */ |
| 1584 | update_res_cache(resolver, &key, PJ_SUCCESS, set_ttl, pkt); |
| 1585 | |
| 1586 | pj_mutex_unlock(resolver->mutex); |
| 1587 | |
| 1588 | return PJ_SUCCESS; |
| 1589 | } |
| 1590 | |
| 1591 | |
| 1592 | /* |
| 1593 | * Get the total number of response in the response cache. |
| 1594 | */ |
| 1595 | PJ_DEF(unsigned) pj_dns_resolver_get_cached_count(pj_dns_resolver *resolver) |
| 1596 | { |
| 1597 | unsigned count; |
| 1598 | |
| 1599 | PJ_ASSERT_RETURN(resolver, 0); |
| 1600 | |
| 1601 | pj_mutex_lock(resolver->mutex); |
| 1602 | count = pj_hash_count(resolver->hrescache); |
| 1603 | pj_mutex_unlock(resolver->mutex); |
| 1604 | |
| 1605 | return count; |
| 1606 | } |
| 1607 | |
| 1608 | |
| 1609 | /* |
| 1610 | * Dump resolver state to the log. |
| 1611 | */ |
| 1612 | PJ_DEF(void) pj_dns_resolver_dump(pj_dns_resolver *resolver, |
| 1613 | pj_bool_t detail) |
| 1614 | { |
| 1615 | #if PJ_LOG_MAX_LEVEL >= 3 |
| 1616 | unsigned i; |
| 1617 | pj_time_val now; |
| 1618 | |
| 1619 | pj_mutex_lock(resolver->mutex); |
| 1620 | |
| 1621 | pj_gettimeofday(&now); |
| 1622 | |
| 1623 | PJ_LOG(3,(resolver->name.ptr, " Dumping resolver state:")); |
| 1624 | |
| 1625 | PJ_LOG(3,(resolver->name.ptr, " Name servers:")); |
| 1626 | for (i=0; i<resolver->ns_count; ++i) { |
| 1627 | const char *state_names[] = { "probing", "active", "bad"}; |
| 1628 | struct nameserver *ns = &resolver->ns[i]; |
| 1629 | |
| 1630 | PJ_LOG(3,(resolver->name.ptr, |
| 1631 | " NS %d: %s:%d (state=%s until %ds, rtt=%d ms)", |
| 1632 | i, pj_inet_ntoa(ns->addr.sin_addr), |
| 1633 | pj_ntohs(ns->addr.sin_port), |
| 1634 | state_names[ns->state], |
| 1635 | ns->state_expiry.sec - now.sec, |
| 1636 | PJ_TIME_VAL_MSEC(ns->rt_delay))); |
| 1637 | } |
| 1638 | |
| 1639 | PJ_LOG(3,(resolver->name.ptr, " Nb. of cached responses: %u", |
| 1640 | pj_hash_count(resolver->hrescache))); |
| 1641 | if (detail) { |
| 1642 | pj_hash_iterator_t itbuf, *it; |
| 1643 | it = pj_hash_first(resolver->hrescache, &itbuf); |
| 1644 | while (it) { |
| 1645 | struct cached_res *cache; |
| 1646 | cache = (struct cached_res*)pj_hash_this(resolver->hrescache, it); |
| 1647 | PJ_LOG(3,(resolver->name.ptr, |
| 1648 | " Type %s: %s", |
| 1649 | pj_dns_get_type_name(cache->key.qtype), |
| 1650 | cache->key.name)); |
| 1651 | it = pj_hash_next(resolver->hrescache, it); |
| 1652 | } |
| 1653 | } |
| 1654 | PJ_LOG(3,(resolver->name.ptr, " Nb. of pending queries: %u (%u)", |
| 1655 | pj_hash_count(resolver->hquerybyid), |
| 1656 | pj_hash_count(resolver->hquerybyres))); |
| 1657 | if (detail) { |
| 1658 | pj_hash_iterator_t itbuf, *it; |
| 1659 | it = pj_hash_first(resolver->hquerybyid, &itbuf); |
| 1660 | while (it) { |
| 1661 | struct pj_dns_async_query *q; |
| 1662 | q = (pj_dns_async_query*) pj_hash_this(resolver->hquerybyid, it); |
| 1663 | PJ_LOG(3,(resolver->name.ptr, |
| 1664 | " Type %s: %s", |
| 1665 | pj_dns_get_type_name(q->key.qtype), |
| 1666 | q->key.name)); |
| 1667 | it = pj_hash_next(resolver->hquerybyid, it); |
| 1668 | } |
| 1669 | } |
| 1670 | PJ_LOG(3,(resolver->name.ptr, " Nb. of pending query free nodes: %u", |
| 1671 | pj_list_size(&resolver->query_free_nodes))); |
| 1672 | PJ_LOG(3,(resolver->name.ptr, " Nb. of timer entries: %u", |
| 1673 | pj_timer_heap_count(resolver->timer))); |
| 1674 | PJ_LOG(3,(resolver->name.ptr, " Pool capacity: %d, used size: %d", |
| 1675 | pj_pool_get_capacity(resolver->pool), |
| 1676 | pj_pool_get_used_size(resolver->pool))); |
| 1677 | |
| 1678 | pj_mutex_unlock(resolver->mutex); |
| 1679 | #endif |
| 1680 | } |
| 1681 | |