1 /***************************************************************************
3 * Project ___| | | | _ \| |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
8 * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
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.
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.
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
22 ***************************************************************************/
31 #ifdef HAVE_SYS_SOCKET_H
32 #include <sys/socket.h>
34 #ifdef HAVE_NETINET_IN_H
35 #include <netinet/in.h>
40 #ifdef HAVE_ARPA_INET_H
41 #include <arpa/inet.h>
44 #include <stdlib.h> /* required for free() prototypes */
47 #include <unistd.h> /* for the close() proto */
70 #include "inet_ntop.h"
72 #define _MPRINTF_REPLACE /* use our functions only */
73 #include <curl/mprintf.h>
75 #if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL)
76 #include "inet_ntoa_r.h"
80 /* The last #include file should be: */
87 * The main COMPILE-TIME DEFINES to keep in mind when reading the host*.c
88 * source file are these:
90 * CURLRES_IPV6 - this host has getaddrinfo() and family, and thus we use
91 * that. The host may not be able to resolve IPv6, but we don't really have to
92 * take that into account. Hosts that aren't IPv6-enabled have CURLRES_IPV4
95 * CURLRES_ARES - is defined if libcurl is built to use c-ares for
96 * asynchronous name resolves. This can be Windows or *nix.
98 * CURLRES_THREADED - is defined if libcurl is built to run under (native)
99 * Windows, and then the name resolve will be done in a new thread, and the
100 * supported API will be the same as for ares-builds.
102 * If any of the two previous are defined, CURLRES_ASYNCH is defined too. If
103 * libcurl is not built to use an asynchronous resolver, CURLRES_SYNCH is
106 * The host*.c sources files are split up like this:
108 * hostip.c - method-independent resolver functions and utility functions
109 * hostasyn.c - functions for asynchronous name resolves
110 * hostsyn.c - functions for synchronous name resolves
111 * hostares.c - functions for ares-using name resolves
112 * hostthre.c - functions for threaded name resolves
113 * hostip4.c - ipv4-specific functions
114 * hostip6.c - ipv6-specific functions
116 * The hostip.h is the united header file for all this. It defines the
117 * CURLRES_* defines based on the config*.h and setup.h defines.
120 /* These two symbols are for the global DNS cache */
121 static struct curl_hash hostname_cache;
122 static int host_cache_initialized;
124 static void freednsentry(void *freethis);
127 * Curl_global_host_cache_init() initializes and sets up a global DNS cache.
128 * Global DNS cache is general badness. Do not use. This will be removed in
129 * a future version. Use the share interface instead!
131 void Curl_global_host_cache_init(void)
133 if (!host_cache_initialized) {
134 Curl_hash_init(&hostname_cache, 7, freednsentry);
135 host_cache_initialized = 1;
140 * Return a pointer to the global cache
142 struct curl_hash *Curl_global_host_cache_get(void)
144 return &hostname_cache;
148 * Destroy and cleanup the global DNS cache
150 void Curl_global_host_cache_dtor(void)
152 if (host_cache_initialized) {
153 Curl_hash_clean(&hostname_cache);
154 host_cache_initialized = 0;
159 * Return # of adresses in a Curl_addrinfo struct
161 int Curl_num_addresses(const Curl_addrinfo *addr)
164 for (i = 0; addr; addr = addr->ai_next, i++)
170 * Curl_printable_address() returns a printable version of the 1st address
171 * given in the 'ip' argument. The result will be stored in the buf that is
174 * If the conversion fails, it returns NULL.
176 const char *Curl_printable_address(const Curl_addrinfo *ip,
177 char *buf, size_t bufsize)
179 const void *ip4 = &((const struct sockaddr_in*)ip->ai_addr)->sin_addr;
180 int af = ip->ai_family;
182 const void *ip6 = &((const struct sockaddr_in6*)ip->ai_addr)->sin6_addr;
184 const void *ip6 = NULL;
187 return Curl_inet_ntop(af, af == AF_INET ? ip4 : ip6, buf, bufsize);
191 * Return a hostcache id string for the providing host + port, to be used by
195 create_hostcache_id(const char *server, int port)
197 /* create and return the new allocated entry */
198 return aprintf("%s:%d", server, port);
201 struct hostcache_prune_data {
207 * This function is set as a callback to be called for every entry in the DNS
208 * cache when we want to prune old unused entries.
210 * Returning non-zero means remove the entry, return 0 to keep it in the
214 hostcache_timestamp_remove(void *datap, void *hc)
216 struct hostcache_prune_data *data =
217 (struct hostcache_prune_data *) datap;
218 struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc;
220 if ((data->now - c->timestamp < data->cache_timeout) ||
222 /* please don't remove */
231 * Prune the DNS cache. This assumes that a lock has already been taken.
234 hostcache_prune(struct curl_hash *hostcache, int cache_timeout, time_t now)
236 struct hostcache_prune_data user;
238 user.cache_timeout = cache_timeout;
241 Curl_hash_clean_with_criterium(hostcache,
243 hostcache_timestamp_remove);
247 * Library-wide function for pruning the DNS cache. This function takes and
248 * returns the appropriate locks.
250 void Curl_hostcache_prune(struct SessionHandle *data)
254 if((data->set.dns_cache_timeout == -1) || !data->dns.hostcache)
255 /* cache forever means never prune, and NULL hostcache means
260 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
264 /* Remove outdated and unused entries from the hostcache */
265 hostcache_prune(data->dns.hostcache,
266 data->set.dns_cache_timeout,
270 Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
274 remove_entry_if_stale(struct SessionHandle *data, struct Curl_dns_entry *dns)
276 struct hostcache_prune_data user;
278 if( !dns || (data->set.dns_cache_timeout == -1) || !data->dns.hostcache)
279 /* cache forever means never prune, and NULL hostcache means
284 user.cache_timeout = data->set.dns_cache_timeout;
286 if ( !hostcache_timestamp_remove(&user,dns) )
289 /* ok, we do need to clear the cache. although we need to remove just a
290 single entry we clean the entire hash, as no explicit delete function
293 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
295 Curl_hash_clean_with_criterium(data->dns.hostcache,
297 hostcache_timestamp_remove);
300 Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
306 #ifdef HAVE_SIGSETJMP
307 /* Beware this is a global and unique instance. This is used to store the
308 return address that we can jump back to from inside a signal handler. This
309 is not thread-safe stuff. */
310 sigjmp_buf curl_jmpenv;
315 * Curl_cache_addr() stores a 'Curl_addrinfo' struct in the DNS cache.
317 * When calling Curl_resolv() has resulted in a response with a returned
318 * address, we call this function to store the information in the dns
321 * Returns the Curl_dns_entry entry pointer or NULL if the storage failed.
323 struct Curl_dns_entry *
324 Curl_cache_addr(struct SessionHandle *data,
326 const char *hostname,
331 struct Curl_dns_entry *dns;
332 struct Curl_dns_entry *dns2;
335 /* Create an entry id, based upon the hostname and port */
336 entry_id = create_hostcache_id(hostname, port);
337 /* If we can't create the entry id, fail */
340 entry_len = strlen(entry_id);
342 /* Create a new cache entry */
343 dns = (struct Curl_dns_entry *) calloc(sizeof(struct Curl_dns_entry), 1);
349 dns->inuse = 0; /* init to not used */
350 dns->addr = addr; /* this is the address(es) */
352 /* Store the resolved data in our DNS cache. This function may return a
353 pointer to an existing struct already present in the hash, and it may
354 return the same argument we pass in. Make no assumptions. */
355 dns2 = Curl_hash_add(data->dns.hostcache, entry_id, entry_len+1,
358 /* Major badness, run away. */
366 dns->timestamp = now; /* used now */
367 dns->inuse++; /* mark entry as in-use */
369 /* free the allocated entry_id again */
376 * Curl_resolv() is the main name resolve function within libcurl. It resolves
377 * a name and returns a pointer to the entry in the 'entry' argument (if one
378 * is provided). This function might return immediately if we're using asynch
379 * resolves. See the return codes.
381 * The cache entry we return will get its 'inuse' counter increased when this
382 * function is used. You MUST call Curl_resolv_unlock() later (when you're
383 * done using this struct) to decrease the counter again.
387 * CURLRESOLV_ERROR (-1) = error, no pointer
388 * CURLRESOLV_RESOLVED (0) = OK, pointer provided
389 * CURLRESOLV_PENDING (1) = waiting for response, no pointer
392 int Curl_resolv(struct connectdata *conn,
393 const char *hostname,
395 struct Curl_dns_entry **entry)
397 char *entry_id = NULL;
398 struct Curl_dns_entry *dns = NULL;
401 struct SessionHandle *data = conn->data;
406 #ifdef HAVE_SIGSETJMP
407 /* this allows us to time-out from the name resolver, as the timeout
408 will generate a signal and we will siglongjmp() from that here */
409 if(!data->set.no_signal) {
410 if (sigsetjmp(curl_jmpenv, 1)) {
411 /* this is coming from a siglongjmp() */
412 failf(data, "name lookup timed out");
413 return CURLRESOLV_ERROR;
418 /* Create an entry id, based upon the hostname and port */
419 entry_id = create_hostcache_id(hostname, port);
420 /* If we can't create the entry id, fail */
422 return CURLRESOLV_ERROR;
424 entry_len = strlen(entry_id);
427 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
429 /* See if its already in our dns cache */
430 dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len+1);
433 Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
435 /* free the allocated entry_id again */
438 /* See whether the returned entry is stale. Deliberately done after the
440 if ( remove_entry_if_stale(data,dns) )
441 dns = NULL; /* the memory deallocation is being handled by the hash */
443 rc = CURLRESOLV_ERROR; /* default to failure */
446 /* The entry was not in the cache. Resolve it to IP address */
450 /* Check what IP specifics the app has requested and if we can provide it.
451 * If not, bail out. */
452 if(!Curl_ipvalid(data))
453 return CURLRESOLV_ERROR;
455 /* If Curl_getaddrinfo() returns NULL, 'wait' might be set to a non-zero
456 value indicating that we need to wait for the response to the resolve
458 addr = Curl_getaddrinfo(conn, hostname, port, &wait);
462 /* the response to our resolve call will come asynchronously at
463 a later time, good or bad */
464 /* First, check that we haven't received the info by now */
465 result = Curl_is_resolved(conn, &dns);
466 if(result) /* error detected */
467 return CURLRESOLV_ERROR;
469 rc = CURLRESOLV_RESOLVED; /* pointer provided */
471 rc = CURLRESOLV_PENDING; /* no info yet */
476 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
478 /* we got a response, store it in the cache */
479 dns = Curl_cache_addr(data, addr, hostname, port);
482 Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
485 /* returned failure, bail out nicely */
486 Curl_freeaddrinfo(addr);
488 rc = CURLRESOLV_RESOLVED;
493 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
494 dns->inuse++; /* we use it! */
496 Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
497 rc = CURLRESOLV_RESOLVED;
506 * Curl_resolv_unlock() unlocks the given cached DNS entry. When this has been
507 * made, the struct may be destroyed due to pruning. It is important that only
508 * one unlock is made for each Curl_resolv() call.
510 void Curl_resolv_unlock(struct SessionHandle *data, struct Curl_dns_entry *dns)
512 DEBUGASSERT(dns && (dns->inuse>0));
515 Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
520 Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
524 * File-internal: free a cache dns entry.
526 static void freednsentry(void *freethis)
528 struct Curl_dns_entry *p = (struct Curl_dns_entry *) freethis;
530 Curl_freeaddrinfo(p->addr);
536 * Curl_mk_dnscache() creates a new DNS cache and returns the handle for it.
538 struct curl_hash *Curl_mk_dnscache(void)
540 return Curl_hash_alloc(7, freednsentry);
543 #ifdef CURLRES_ADDRINFO_COPY
545 /* align on even 64bit boundaries */
546 #define MEMALIGN(x) ((x)+(8-(((unsigned long)(x))&0x7)))
549 * Curl_addrinfo_copy() performs a "deep" copy of a hostent into a buffer and
550 * returns a pointer to the malloc()ed copy. You need to call free() on the
551 * returned buffer when you're done with it.
553 Curl_addrinfo *Curl_addrinfo_copy(const void *org, int port)
555 const struct hostent *orig = org;
557 return Curl_he2ai(orig, port);
559 #endif /* CURLRES_ADDRINFO_COPY */
561 /***********************************************************************
562 * Only for plain-ipv4 and c-ares builds
563 **********************************************************************/
565 #if defined(CURLRES_IPV4) || defined(CURLRES_ARES)
567 * This is a function for freeing name information in a protocol independent
570 void Curl_freeaddrinfo(Curl_addrinfo *ai)
574 /* walk over the list and free all entries */
583 struct hostent hostentry;
584 char *h_addr_list[2];
585 struct in_addr addrentry;
586 char h_name[16]; /* 123.123.123.123 = 15 letters is maximum */
590 * Curl_ip2addr() takes a 32bit ipv4 internet address as input parameter
591 * together with a pointer to the string version of the address, and it
592 * returns a Curl_addrinfo chain filled in correctly with information for this
595 * The input parameters ARE NOT checked for validity but they are expected
596 * to have been checked already when this is called.
598 Curl_addrinfo *Curl_ip2addr(in_addr_t num, const char *hostname, int port)
602 struct in_addr *addrentry;
603 struct namebuf buffer;
604 struct namebuf *buf = &buffer;
607 h->h_addr_list = &buf->h_addr_list[0];
608 addrentry = &buf->addrentry;
610 /* On UNICOS, s_addr is a bit field and for some reason assigning to it
611 * doesn't work. There must be a better fix than this ugly hack.
613 memcpy(addrentry, &num, SIZEOF_in_addr);
615 addrentry->s_addr = num;
617 h->h_addr_list[0] = (char*)addrentry;
618 h->h_addr_list[1] = NULL;
619 h->h_addrtype = AF_INET;
620 h->h_length = sizeof(*addrentry);
621 h->h_name = &buf->h_name[0];
624 /* Now store the dotted version of the address */
625 snprintf((char *)h->h_name, 16, "%s", hostname);
627 ai = Curl_he2ai(h, port);