1/*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al. 9 * 10 * This software is licensed as described in the file COPYING, which 11 * you should have received as part of this distribution. The terms 12 * are also available at http://curl.haxx.se/docs/copyright.html. 13 * 14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell 15 * copies of the Software, and permit persons to whom the Software is 16 * furnished to do so, under the terms of the COPYING file. 17 * 18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 19 * KIND, either express or implied. 20 * 21 ***************************************************************************/ 22 23#include "curl_setup.h" 24 25#ifdef HAVE_NETINET_IN_H 26#include <netinet/in.h> 27#endif 28#ifdef HAVE_NETDB_H 29#include <netdb.h> 30#endif 31#ifdef HAVE_ARPA_INET_H 32#include <arpa/inet.h> 33#endif 34#ifdef __VMS 35#include <in.h> 36#include <inet.h> 37#endif 38 39#ifdef HAVE_SETJMP_H 40#include <setjmp.h> 41#endif 42#ifdef HAVE_SIGNAL_H 43#include <signal.h> 44#endif 45 46#ifdef HAVE_PROCESS_H 47#include <process.h> 48#endif 49 50#include "urldata.h" 51#include "sendf.h" 52#include "hostip.h" 53#include "hash.h" 54#include "share.h" 55#include "strerror.h" 56#include "url.h" 57#include "inet_ntop.h" 58#include "warnless.h" 59 60#define _MPRINTF_REPLACE /* use our functions only */ 61#include <curl/mprintf.h> 62 63#include "curl_memory.h" 64/* The last #include file should be: */ 65#include "memdebug.h" 66 67#if defined(CURLRES_SYNCH) && \ 68 defined(HAVE_ALARM) && defined(SIGALRM) && defined(HAVE_SIGSETJMP) 69/* alarm-based timeouts can only be used with all the dependencies satisfied */ 70#define USE_ALARM_TIMEOUT 71#endif 72 73/* 74 * hostip.c explained 75 * ================== 76 * 77 * The main COMPILE-TIME DEFINES to keep in mind when reading the host*.c 78 * source file are these: 79 * 80 * CURLRES_IPV6 - this host has getaddrinfo() and family, and thus we use 81 * that. The host may not be able to resolve IPv6, but we don't really have to 82 * take that into account. Hosts that aren't IPv6-enabled have CURLRES_IPV4 83 * defined. 84 * 85 * CURLRES_ARES - is defined if libcurl is built to use c-ares for 86 * asynchronous name resolves. This can be Windows or *nix. 87 * 88 * CURLRES_THREADED - is defined if libcurl is built to run under (native) 89 * Windows, and then the name resolve will be done in a new thread, and the 90 * supported API will be the same as for ares-builds. 91 * 92 * If any of the two previous are defined, CURLRES_ASYNCH is defined too. If 93 * libcurl is not built to use an asynchronous resolver, CURLRES_SYNCH is 94 * defined. 95 * 96 * The host*.c sources files are split up like this: 97 * 98 * hostip.c - method-independent resolver functions and utility functions 99 * hostasyn.c - functions for asynchronous name resolves 100 * hostsyn.c - functions for synchronous name resolves 101 * hostip4.c - ipv4-specific functions 102 * hostip6.c - ipv6-specific functions 103 * 104 * The two asynchronous name resolver backends are implemented in: 105 * asyn-ares.c - functions for ares-using name resolves 106 * asyn-thread.c - functions for threaded name resolves 107 108 * The hostip.h is the united header file for all this. It defines the 109 * CURLRES_* defines based on the config*.h and curl_setup.h defines. 110 */ 111 112/* These two symbols are for the global DNS cache */ 113static struct curl_hash hostname_cache; 114static int host_cache_initialized; 115 116static void freednsentry(void *freethis); 117 118/* 119 * Curl_global_host_cache_init() initializes and sets up a global DNS cache. 120 * Global DNS cache is general badness. Do not use. This will be removed in 121 * a future version. Use the share interface instead! 122 * 123 * Returns a struct curl_hash pointer on success, NULL on failure. 124 */ 125struct curl_hash *Curl_global_host_cache_init(void) 126{ 127 int rc = 0; 128 if(!host_cache_initialized) { 129 rc = Curl_hash_init(&hostname_cache, 7, Curl_hash_str, 130 Curl_str_key_compare, freednsentry); 131 if(!rc) 132 host_cache_initialized = 1; 133 } 134 return rc?NULL:&hostname_cache; 135} 136 137/* 138 * Destroy and cleanup the global DNS cache 139 */ 140void Curl_global_host_cache_dtor(void) 141{ 142 if(host_cache_initialized) { 143 /* first make sure that any custom "CURLOPT_RESOLVE" names are 144 cleared off */ 145 Curl_hostcache_clean(NULL, &hostname_cache); 146 /* then free the remaining hash completely */ 147 Curl_hash_clean(&hostname_cache); 148 host_cache_initialized = 0; 149 } 150} 151 152/* 153 * Return # of adresses in a Curl_addrinfo struct 154 */ 155int Curl_num_addresses(const Curl_addrinfo *addr) 156{ 157 int i = 0; 158 while(addr) { 159 addr = addr->ai_next; 160 i++; 161 } 162 return i; 163} 164 165/* 166 * Curl_printable_address() returns a printable version of the 1st address 167 * given in the 'ai' argument. The result will be stored in the buf that is 168 * bufsize bytes big. 169 * 170 * If the conversion fails, it returns NULL. 171 */ 172const char * 173Curl_printable_address(const Curl_addrinfo *ai, char *buf, size_t bufsize) 174{ 175 const struct sockaddr_in *sa4; 176 const struct in_addr *ipaddr4; 177#ifdef ENABLE_IPV6 178 const struct sockaddr_in6 *sa6; 179 const struct in6_addr *ipaddr6; 180#endif 181 182 switch (ai->ai_family) { 183 case AF_INET: 184 sa4 = (const void *)ai->ai_addr; 185 ipaddr4 = &sa4->sin_addr; 186 return Curl_inet_ntop(ai->ai_family, (const void *)ipaddr4, buf, 187 bufsize); 188#ifdef ENABLE_IPV6 189 case AF_INET6: 190 sa6 = (const void *)ai->ai_addr; 191 ipaddr6 = &sa6->sin6_addr; 192 return Curl_inet_ntop(ai->ai_family, (const void *)ipaddr6, buf, 193 bufsize); 194#endif 195 default: 196 break; 197 } 198 return NULL; 199} 200 201/* 202 * Return a hostcache id string for the provided host + port, to be used by 203 * the DNS caching. 204 */ 205static char * 206create_hostcache_id(const char *name, int port) 207{ 208 /* create and return the new allocated entry */ 209 char *id = aprintf("%s:%d", name, port); 210 char *ptr = id; 211 if(ptr) { 212 /* lower case the name part */ 213 while(*ptr && (*ptr != ':')) { 214 *ptr = (char)TOLOWER(*ptr); 215 ptr++; 216 } 217 } 218 return id; 219} 220 221struct hostcache_prune_data { 222 long cache_timeout; 223 time_t now; 224}; 225 226/* 227 * This function is set as a callback to be called for every entry in the DNS 228 * cache when we want to prune old unused entries. 229 * 230 * Returning non-zero means remove the entry, return 0 to keep it in the 231 * cache. 232 */ 233static int 234hostcache_timestamp_remove(void *datap, void *hc) 235{ 236 struct hostcache_prune_data *data = 237 (struct hostcache_prune_data *) datap; 238 struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc; 239 240 return !c->inuse && (data->now - c->timestamp >= data->cache_timeout); 241} 242 243/* 244 * Prune the DNS cache. This assumes that a lock has already been taken. 245 */ 246static void 247hostcache_prune(struct curl_hash *hostcache, long cache_timeout, time_t now) 248{ 249 struct hostcache_prune_data user; 250 251 user.cache_timeout = cache_timeout; 252 user.now = now; 253 254 Curl_hash_clean_with_criterium(hostcache, 255 (void *) &user, 256 hostcache_timestamp_remove); 257} 258 259/* 260 * Library-wide function for pruning the DNS cache. This function takes and 261 * returns the appropriate locks. 262 */ 263void Curl_hostcache_prune(struct SessionHandle *data) 264{ 265 time_t now; 266 267 if((data->set.dns_cache_timeout == -1) || !data->dns.hostcache) 268 /* cache forever means never prune, and NULL hostcache means 269 we can't do it */ 270 return; 271 272 if(data->share) 273 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 274 275 time(&now); 276 277 /* Remove outdated and unused entries from the hostcache */ 278 hostcache_prune(data->dns.hostcache, 279 data->set.dns_cache_timeout, 280 now); 281 282 if(data->share) 283 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 284} 285 286/* 287 * Check if the entry should be pruned. Assumes a locked cache. 288 */ 289static int 290remove_entry_if_stale(struct SessionHandle *data, struct Curl_dns_entry *dns) 291{ 292 struct hostcache_prune_data user; 293 294 if(!dns || (data->set.dns_cache_timeout == -1) || !data->dns.hostcache || 295 dns->inuse) 296 /* cache forever means never prune, and NULL hostcache means we can't do 297 it, if it still is in use then we leave it */ 298 return 0; 299 300 time(&user.now); 301 user.cache_timeout = data->set.dns_cache_timeout; 302 303 if(!hostcache_timestamp_remove(&user,dns) ) 304 return 0; 305 306 Curl_hash_clean_with_criterium(data->dns.hostcache, 307 (void *) &user, 308 hostcache_timestamp_remove); 309 310 return 1; 311} 312 313 314#ifdef HAVE_SIGSETJMP 315/* Beware this is a global and unique instance. This is used to store the 316 return address that we can jump back to from inside a signal handler. This 317 is not thread-safe stuff. */ 318sigjmp_buf curl_jmpenv; 319#endif 320 321 322/* 323 * Curl_cache_addr() stores a 'Curl_addrinfo' struct in the DNS cache. 324 * 325 * When calling Curl_resolv() has resulted in a response with a returned 326 * address, we call this function to store the information in the dns 327 * cache etc 328 * 329 * Returns the Curl_dns_entry entry pointer or NULL if the storage failed. 330 */ 331struct Curl_dns_entry * 332Curl_cache_addr(struct SessionHandle *data, 333 Curl_addrinfo *addr, 334 const char *hostname, 335 int port) 336{ 337 char *entry_id; 338 size_t entry_len; 339 struct Curl_dns_entry *dns; 340 struct Curl_dns_entry *dns2; 341 342 /* Create an entry id, based upon the hostname and port */ 343 entry_id = create_hostcache_id(hostname, port); 344 /* If we can't create the entry id, fail */ 345 if(!entry_id) 346 return NULL; 347 entry_len = strlen(entry_id); 348 349 /* Create a new cache entry */ 350 dns = calloc(1, sizeof(struct Curl_dns_entry)); 351 if(!dns) { 352 free(entry_id); 353 return NULL; 354 } 355 356 dns->inuse = 0; /* init to not used */ 357 dns->addr = addr; /* this is the address(es) */ 358 time(&dns->timestamp); 359 if(dns->timestamp == 0) 360 dns->timestamp = 1; /* zero indicates that entry isn't in hash table */ 361 362 /* Store the resolved data in our DNS cache. */ 363 dns2 = Curl_hash_add(data->dns.hostcache, entry_id, entry_len+1, 364 (void *)dns); 365 if(!dns2) { 366 free(dns); 367 free(entry_id); 368 return NULL; 369 } 370 371 dns = dns2; 372 dns->inuse++; /* mark entry as in-use */ 373 374 /* free the allocated entry_id */ 375 free(entry_id); 376 377 return dns; 378} 379 380/* 381 * Curl_resolv() is the main name resolve function within libcurl. It resolves 382 * a name and returns a pointer to the entry in the 'entry' argument (if one 383 * is provided). This function might return immediately if we're using asynch 384 * resolves. See the return codes. 385 * 386 * The cache entry we return will get its 'inuse' counter increased when this 387 * function is used. You MUST call Curl_resolv_unlock() later (when you're 388 * done using this struct) to decrease the counter again. 389 * 390 * In debug mode, we specifically test for an interface name "LocalHost" 391 * and resolve "localhost" instead as a means to permit test cases 392 * to connect to a local test server with any host name. 393 * 394 * Return codes: 395 * 396 * CURLRESOLV_ERROR (-1) = error, no pointer 397 * CURLRESOLV_RESOLVED (0) = OK, pointer provided 398 * CURLRESOLV_PENDING (1) = waiting for response, no pointer 399 */ 400 401int Curl_resolv(struct connectdata *conn, 402 const char *hostname, 403 int port, 404 struct Curl_dns_entry **entry) 405{ 406 char *entry_id = NULL; 407 struct Curl_dns_entry *dns = NULL; 408 size_t entry_len; 409 struct SessionHandle *data = conn->data; 410 CURLcode result; 411 int rc = CURLRESOLV_ERROR; /* default to failure */ 412 413 *entry = NULL; 414 415 /* Create an entry id, based upon the hostname and port */ 416 entry_id = create_hostcache_id(hostname, port); 417 /* If we can't create the entry id, fail */ 418 if(!entry_id) 419 return rc; 420 421 entry_len = strlen(entry_id); 422 423 if(data->share) 424 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 425 426 /* See if its already in our dns cache */ 427 dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len+1); 428 429 /* free the allocated entry_id again */ 430 free(entry_id); 431 432 infof(data, "Hostname was %sfound in DNS cache\n", dns?"":"NOT "); 433 434 /* See whether the returned entry is stale. Done before we release lock */ 435 if(remove_entry_if_stale(data, dns)) { 436 infof(data, "Hostname in DNS cache was stale, zapped\n"); 437 dns = NULL; /* the memory deallocation is being handled by the hash */ 438 } 439 440 if(dns) { 441 dns->inuse++; /* we use it! */ 442 rc = CURLRESOLV_RESOLVED; 443 } 444 445 if(data->share) 446 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 447 448 if(!dns) { 449 /* The entry was not in the cache. Resolve it to IP address */ 450 451 Curl_addrinfo *addr; 452 int respwait; 453 454 /* Check what IP specifics the app has requested and if we can provide it. 455 * If not, bail out. */ 456 if(!Curl_ipvalid(conn)) 457 return CURLRESOLV_ERROR; 458 459 /* If Curl_getaddrinfo() returns NULL, 'respwait' might be set to a 460 non-zero value indicating that we need to wait for the response to the 461 resolve call */ 462 addr = Curl_getaddrinfo(conn, 463#ifdef DEBUGBUILD 464 (data->set.str[STRING_DEVICE] 465 && !strcmp(data->set.str[STRING_DEVICE], 466 "LocalHost"))?"localhost": 467#endif 468 hostname, port, &respwait); 469 470 if(!addr) { 471 if(respwait) { 472 /* the response to our resolve call will come asynchronously at 473 a later time, good or bad */ 474 /* First, check that we haven't received the info by now */ 475 result = Curl_resolver_is_resolved(conn, &dns); 476 if(result) /* error detected */ 477 return CURLRESOLV_ERROR; 478 if(dns) 479 rc = CURLRESOLV_RESOLVED; /* pointer provided */ 480 else 481 rc = CURLRESOLV_PENDING; /* no info yet */ 482 } 483 } 484 else { 485 if(data->share) 486 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 487 488 /* we got a response, store it in the cache */ 489 dns = Curl_cache_addr(data, addr, hostname, port); 490 491 if(data->share) 492 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 493 494 if(!dns) 495 /* returned failure, bail out nicely */ 496 Curl_freeaddrinfo(addr); 497 else 498 rc = CURLRESOLV_RESOLVED; 499 } 500 } 501 502 *entry = dns; 503 504 return rc; 505} 506 507#ifdef USE_ALARM_TIMEOUT 508/* 509 * This signal handler jumps back into the main libcurl code and continues 510 * execution. This effectively causes the remainder of the application to run 511 * within a signal handler which is nonportable and could lead to problems. 512 */ 513static 514RETSIGTYPE alarmfunc(int sig) 515{ 516 /* this is for "-ansi -Wall -pedantic" to stop complaining! (rabe) */ 517 (void)sig; 518 siglongjmp(curl_jmpenv, 1); 519 return; 520} 521#endif /* USE_ALARM_TIMEOUT */ 522 523/* 524 * Curl_resolv_timeout() is the same as Curl_resolv() but specifies a 525 * timeout. This function might return immediately if we're using asynch 526 * resolves. See the return codes. 527 * 528 * The cache entry we return will get its 'inuse' counter increased when this 529 * function is used. You MUST call Curl_resolv_unlock() later (when you're 530 * done using this struct) to decrease the counter again. 531 * 532 * If built with a synchronous resolver and use of signals is not 533 * disabled by the application, then a nonzero timeout will cause a 534 * timeout after the specified number of milliseconds. Otherwise, timeout 535 * is ignored. 536 * 537 * Return codes: 538 * 539 * CURLRESOLV_TIMEDOUT(-2) = warning, time too short or previous alarm expired 540 * CURLRESOLV_ERROR (-1) = error, no pointer 541 * CURLRESOLV_RESOLVED (0) = OK, pointer provided 542 * CURLRESOLV_PENDING (1) = waiting for response, no pointer 543 */ 544 545int Curl_resolv_timeout(struct connectdata *conn, 546 const char *hostname, 547 int port, 548 struct Curl_dns_entry **entry, 549 long timeoutms) 550{ 551#ifdef USE_ALARM_TIMEOUT 552#ifdef HAVE_SIGACTION 553 struct sigaction keep_sigact; /* store the old struct here */ 554 volatile bool keep_copysig = FALSE; /* wether old sigact has been saved */ 555 struct sigaction sigact; 556#else 557#ifdef HAVE_SIGNAL 558 void (*keep_sigact)(int); /* store the old handler here */ 559#endif /* HAVE_SIGNAL */ 560#endif /* HAVE_SIGACTION */ 561 volatile long timeout; 562 volatile unsigned int prev_alarm = 0; 563 struct SessionHandle *data = conn->data; 564#endif /* USE_ALARM_TIMEOUT */ 565 int rc; 566 567 *entry = NULL; 568 569 if(timeoutms < 0) 570 /* got an already expired timeout */ 571 return CURLRESOLV_TIMEDOUT; 572 573#ifdef USE_ALARM_TIMEOUT 574 if(data->set.no_signal) 575 /* Ignore the timeout when signals are disabled */ 576 timeout = 0; 577 else 578 timeout = timeoutms; 579 580 if(!timeout) 581 /* USE_ALARM_TIMEOUT defined, but no timeout actually requested */ 582 return Curl_resolv(conn, hostname, port, entry); 583 584 if(timeout < 1000) 585 /* The alarm() function only provides integer second resolution, so if 586 we want to wait less than one second we must bail out already now. */ 587 return CURLRESOLV_TIMEDOUT; 588 589 /************************************************************* 590 * Set signal handler to catch SIGALRM 591 * Store the old value to be able to set it back later! 592 *************************************************************/ 593#ifdef HAVE_SIGACTION 594 sigaction(SIGALRM, NULL, &sigact); 595 keep_sigact = sigact; 596 keep_copysig = TRUE; /* yes, we have a copy */ 597 sigact.sa_handler = alarmfunc; 598#ifdef SA_RESTART 599 /* HPUX doesn't have SA_RESTART but defaults to that behaviour! */ 600 sigact.sa_flags &= ~SA_RESTART; 601#endif 602 /* now set the new struct */ 603 sigaction(SIGALRM, &sigact, NULL); 604#else /* HAVE_SIGACTION */ 605 /* no sigaction(), revert to the much lamer signal() */ 606#ifdef HAVE_SIGNAL 607 keep_sigact = signal(SIGALRM, alarmfunc); 608#endif 609#endif /* HAVE_SIGACTION */ 610 611 /* alarm() makes a signal get sent when the timeout fires off, and that 612 will abort system calls */ 613 prev_alarm = alarm(curlx_sltoui(timeout/1000L)); 614 615 /* This allows us to time-out from the name resolver, as the timeout 616 will generate a signal and we will siglongjmp() from that here. 617 This technique has problems (see alarmfunc). 618 This should be the last thing we do before calling Curl_resolv(), 619 as otherwise we'd have to worry about variables that get modified 620 before we invoke Curl_resolv() (and thus use "volatile"). */ 621 if(sigsetjmp(curl_jmpenv, 1)) { 622 /* this is coming from a siglongjmp() after an alarm signal */ 623 failf(data, "name lookup timed out"); 624 rc = CURLRESOLV_ERROR; 625 goto clean_up; 626 } 627 628#else 629#ifndef CURLRES_ASYNCH 630 if(timeoutms) 631 infof(conn->data, "timeout on name lookup is not supported\n"); 632#else 633 (void)timeoutms; /* timeoutms not used with an async resolver */ 634#endif 635#endif /* USE_ALARM_TIMEOUT */ 636 637 /* Perform the actual name resolution. This might be interrupted by an 638 * alarm if it takes too long. 639 */ 640 rc = Curl_resolv(conn, hostname, port, entry); 641 642#ifdef USE_ALARM_TIMEOUT 643clean_up: 644 645 if(!prev_alarm) 646 /* deactivate a possibly active alarm before uninstalling the handler */ 647 alarm(0); 648 649#ifdef HAVE_SIGACTION 650 if(keep_copysig) { 651 /* we got a struct as it looked before, now put that one back nice 652 and clean */ 653 sigaction(SIGALRM, &keep_sigact, NULL); /* put it back */ 654 } 655#else 656#ifdef HAVE_SIGNAL 657 /* restore the previous SIGALRM handler */ 658 signal(SIGALRM, keep_sigact); 659#endif 660#endif /* HAVE_SIGACTION */ 661 662 /* switch back the alarm() to either zero or to what it was before minus 663 the time we spent until now! */ 664 if(prev_alarm) { 665 /* there was an alarm() set before us, now put it back */ 666 unsigned long elapsed_ms = Curl_tvdiff(Curl_tvnow(), conn->created); 667 668 /* the alarm period is counted in even number of seconds */ 669 unsigned long alarm_set = prev_alarm - elapsed_ms/1000; 670 671 if(!alarm_set || 672 ((alarm_set >= 0x80000000) && (prev_alarm < 0x80000000)) ) { 673 /* if the alarm time-left reached zero or turned "negative" (counted 674 with unsigned values), we should fire off a SIGALRM here, but we 675 won't, and zero would be to switch it off so we never set it to 676 less than 1! */ 677 alarm(1); 678 rc = CURLRESOLV_TIMEDOUT; 679 failf(data, "Previous alarm fired off!"); 680 } 681 else 682 alarm((unsigned int)alarm_set); 683 } 684#endif /* USE_ALARM_TIMEOUT */ 685 686 return rc; 687} 688 689/* 690 * Curl_resolv_unlock() unlocks the given cached DNS entry. When this has been 691 * made, the struct may be destroyed due to pruning. It is important that only 692 * one unlock is made for each Curl_resolv() call. 693 * 694 * May be called with 'data' == NULL for global cache. 695 */ 696void Curl_resolv_unlock(struct SessionHandle *data, struct Curl_dns_entry *dns) 697{ 698 DEBUGASSERT(dns && (dns->inuse>0)); 699 700 if(data && data->share) 701 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 702 703 dns->inuse--; 704 /* only free if nobody is using AND it is not in hostcache (timestamp == 705 0) */ 706 if(dns->inuse == 0 && dns->timestamp == 0) { 707 Curl_freeaddrinfo(dns->addr); 708 free(dns); 709 } 710 711 if(data && data->share) 712 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 713} 714 715/* 716 * File-internal: free a cache dns entry. 717 */ 718static void freednsentry(void *freethis) 719{ 720 struct Curl_dns_entry *p = (struct Curl_dns_entry *) freethis; 721 722 /* mark the entry as not in hostcache */ 723 p->timestamp = 0; 724 if(p->inuse == 0) { 725 Curl_freeaddrinfo(p->addr); 726 free(p); 727 } 728} 729 730/* 731 * Curl_mk_dnscache() creates a new DNS cache and returns the handle for it. 732 */ 733struct curl_hash *Curl_mk_dnscache(void) 734{ 735 return Curl_hash_alloc(7, Curl_hash_str, Curl_str_key_compare, freednsentry); 736} 737 738static int hostcache_inuse(void *data, void *hc) 739{ 740 struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc; 741 742 if(c->inuse == 1) 743 Curl_resolv_unlock(data, c); 744 745 return 1; /* free all entries */ 746} 747 748/* 749 * Curl_hostcache_clean() 750 * 751 * This _can_ be called with 'data' == NULL but then of course no locking 752 * can be done! 753 */ 754 755void Curl_hostcache_clean(struct SessionHandle *data, 756 struct curl_hash *hash) 757{ 758 /* Entries added to the hostcache with the CURLOPT_RESOLVE function are 759 * still present in the cache with the inuse counter set to 1. Detect them 760 * and cleanup! 761 */ 762 Curl_hash_clean_with_criterium(hash, data, hostcache_inuse); 763} 764 765 766CURLcode Curl_loadhostpairs(struct SessionHandle *data) 767{ 768 struct curl_slist *hostp; 769 char hostname[256]; 770 char address[256]; 771 int port; 772 773 for(hostp = data->change.resolve; hostp; hostp = hostp->next ) { 774 if(!hostp->data) 775 continue; 776 if(hostp->data[0] == '-') { 777 /* TODO: mark an entry for removal */ 778 } 779 else if(3 == sscanf(hostp->data, "%255[^:]:%d:%255s", hostname, &port, 780 address)) { 781 struct Curl_dns_entry *dns; 782 Curl_addrinfo *addr; 783 char *entry_id; 784 size_t entry_len; 785 786 addr = Curl_str2addr(address, port); 787 if(!addr) { 788 infof(data, "Resolve %s found illegal!\n", hostp->data); 789 continue; 790 } 791 792 /* Create an entry id, based upon the hostname and port */ 793 entry_id = create_hostcache_id(hostname, port); 794 /* If we can't create the entry id, fail */ 795 if(!entry_id) { 796 Curl_freeaddrinfo(addr); 797 return CURLE_OUT_OF_MEMORY; 798 } 799 800 entry_len = strlen(entry_id); 801 802 if(data->share) 803 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE); 804 805 /* See if its already in our dns cache */ 806 dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len+1); 807 808 /* free the allocated entry_id again */ 809 free(entry_id); 810 811 if(!dns) 812 /* if not in the cache already, put this host in the cache */ 813 dns = Curl_cache_addr(data, addr, hostname, port); 814 else 815 /* this is a duplicate, free it again */ 816 Curl_freeaddrinfo(addr); 817 818 if(data->share) 819 Curl_share_unlock(data, CURL_LOCK_DATA_DNS); 820 821 if(!dns) { 822 Curl_freeaddrinfo(addr); 823 return CURLE_OUT_OF_MEMORY; 824 } 825 infof(data, "Added %s:%d:%s to DNS cache\n", 826 hostname, port, address); 827 } 828 } 829 data->change.resolve = NULL; /* dealt with now */ 830 831 return CURLE_OK; 832} 833