1 | /***************************************************************************
|
---|
2 | * _ _ ____ _
|
---|
3 | * Project ___| | | | _ \| |
|
---|
4 | * / __| | | | |_) | |
|
---|
5 | * | (__| |_| | _ <| |___
|
---|
6 | * \___|\___/|_| \_\_____|
|
---|
7 | *
|
---|
8 | * Copyright (C) 1998 - 2017, 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 https://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 | /* The last 3 #include files should be in this order */
|
---|
60 | #include "curl_printf.h"
|
---|
61 | #include "curl_memory.h"
|
---|
62 | #include "memdebug.h"
|
---|
63 |
|
---|
64 | #if defined(CURLRES_SYNCH) && \
|
---|
65 | defined(HAVE_ALARM) && defined(SIGALRM) && defined(HAVE_SIGSETJMP)
|
---|
66 | /* alarm-based timeouts can only be used with all the dependencies satisfied */
|
---|
67 | #define USE_ALARM_TIMEOUT
|
---|
68 | #endif
|
---|
69 |
|
---|
70 | /*
|
---|
71 | * hostip.c explained
|
---|
72 | * ==================
|
---|
73 | *
|
---|
74 | * The main COMPILE-TIME DEFINES to keep in mind when reading the host*.c
|
---|
75 | * source file are these:
|
---|
76 | *
|
---|
77 | * CURLRES_IPV6 - this host has getaddrinfo() and family, and thus we use
|
---|
78 | * that. The host may not be able to resolve IPv6, but we don't really have to
|
---|
79 | * take that into account. Hosts that aren't IPv6-enabled have CURLRES_IPV4
|
---|
80 | * defined.
|
---|
81 | *
|
---|
82 | * CURLRES_ARES - is defined if libcurl is built to use c-ares for
|
---|
83 | * asynchronous name resolves. This can be Windows or *nix.
|
---|
84 | *
|
---|
85 | * CURLRES_THREADED - is defined if libcurl is built to run under (native)
|
---|
86 | * Windows, and then the name resolve will be done in a new thread, and the
|
---|
87 | * supported API will be the same as for ares-builds.
|
---|
88 | *
|
---|
89 | * If any of the two previous are defined, CURLRES_ASYNCH is defined too. If
|
---|
90 | * libcurl is not built to use an asynchronous resolver, CURLRES_SYNCH is
|
---|
91 | * defined.
|
---|
92 | *
|
---|
93 | * The host*.c sources files are split up like this:
|
---|
94 | *
|
---|
95 | * hostip.c - method-independent resolver functions and utility functions
|
---|
96 | * hostasyn.c - functions for asynchronous name resolves
|
---|
97 | * hostsyn.c - functions for synchronous name resolves
|
---|
98 | * hostip4.c - IPv4 specific functions
|
---|
99 | * hostip6.c - IPv6 specific functions
|
---|
100 | *
|
---|
101 | * The two asynchronous name resolver backends are implemented in:
|
---|
102 | * asyn-ares.c - functions for ares-using name resolves
|
---|
103 | * asyn-thread.c - functions for threaded name resolves
|
---|
104 |
|
---|
105 | * The hostip.h is the united header file for all this. It defines the
|
---|
106 | * CURLRES_* defines based on the config*.h and curl_setup.h defines.
|
---|
107 | */
|
---|
108 |
|
---|
109 | /* These two symbols are for the global DNS cache */
|
---|
110 | static struct curl_hash hostname_cache;
|
---|
111 | static int host_cache_initialized;
|
---|
112 |
|
---|
113 | static void freednsentry(void *freethis);
|
---|
114 |
|
---|
115 | /*
|
---|
116 | * Curl_global_host_cache_init() initializes and sets up a global DNS cache.
|
---|
117 | * Global DNS cache is general badness. Do not use. This will be removed in
|
---|
118 | * a future version. Use the share interface instead!
|
---|
119 | *
|
---|
120 | * Returns a struct curl_hash pointer on success, NULL on failure.
|
---|
121 | */
|
---|
122 | struct curl_hash *Curl_global_host_cache_init(void)
|
---|
123 | {
|
---|
124 | int rc = 0;
|
---|
125 | if(!host_cache_initialized) {
|
---|
126 | rc = Curl_hash_init(&hostname_cache, 7, Curl_hash_str,
|
---|
127 | Curl_str_key_compare, freednsentry);
|
---|
128 | if(!rc)
|
---|
129 | host_cache_initialized = 1;
|
---|
130 | }
|
---|
131 | return rc?NULL:&hostname_cache;
|
---|
132 | }
|
---|
133 |
|
---|
134 | /*
|
---|
135 | * Destroy and cleanup the global DNS cache
|
---|
136 | */
|
---|
137 | void Curl_global_host_cache_dtor(void)
|
---|
138 | {
|
---|
139 | if(host_cache_initialized) {
|
---|
140 | Curl_hash_destroy(&hostname_cache);
|
---|
141 | host_cache_initialized = 0;
|
---|
142 | }
|
---|
143 | }
|
---|
144 |
|
---|
145 | /*
|
---|
146 | * Return # of addresses in a Curl_addrinfo struct
|
---|
147 | */
|
---|
148 | int Curl_num_addresses(const Curl_addrinfo *addr)
|
---|
149 | {
|
---|
150 | int i = 0;
|
---|
151 | while(addr) {
|
---|
152 | addr = addr->ai_next;
|
---|
153 | i++;
|
---|
154 | }
|
---|
155 | return i;
|
---|
156 | }
|
---|
157 |
|
---|
158 | /*
|
---|
159 | * Curl_printable_address() returns a printable version of the 1st address
|
---|
160 | * given in the 'ai' argument. The result will be stored in the buf that is
|
---|
161 | * bufsize bytes big.
|
---|
162 | *
|
---|
163 | * If the conversion fails, it returns NULL.
|
---|
164 | */
|
---|
165 | const char *
|
---|
166 | Curl_printable_address(const Curl_addrinfo *ai, char *buf, size_t bufsize)
|
---|
167 | {
|
---|
168 | const struct sockaddr_in *sa4;
|
---|
169 | const struct in_addr *ipaddr4;
|
---|
170 | #ifdef ENABLE_IPV6
|
---|
171 | const struct sockaddr_in6 *sa6;
|
---|
172 | const struct in6_addr *ipaddr6;
|
---|
173 | #endif
|
---|
174 |
|
---|
175 | switch(ai->ai_family) {
|
---|
176 | case AF_INET:
|
---|
177 | sa4 = (const void *)ai->ai_addr;
|
---|
178 | ipaddr4 = &sa4->sin_addr;
|
---|
179 | return Curl_inet_ntop(ai->ai_family, (const void *)ipaddr4, buf,
|
---|
180 | bufsize);
|
---|
181 | #ifdef ENABLE_IPV6
|
---|
182 | case AF_INET6:
|
---|
183 | sa6 = (const void *)ai->ai_addr;
|
---|
184 | ipaddr6 = &sa6->sin6_addr;
|
---|
185 | return Curl_inet_ntop(ai->ai_family, (const void *)ipaddr6, buf,
|
---|
186 | bufsize);
|
---|
187 | #endif
|
---|
188 | default:
|
---|
189 | break;
|
---|
190 | }
|
---|
191 | return NULL;
|
---|
192 | }
|
---|
193 |
|
---|
194 | /*
|
---|
195 | * Return a hostcache id string for the provided host + port, to be used by
|
---|
196 | * the DNS caching.
|
---|
197 | */
|
---|
198 | static char *
|
---|
199 | create_hostcache_id(const char *name, int port)
|
---|
200 | {
|
---|
201 | /* create and return the new allocated entry */
|
---|
202 | char *id = aprintf("%s:%d", name, port);
|
---|
203 | char *ptr = id;
|
---|
204 | if(ptr) {
|
---|
205 | /* lower case the name part */
|
---|
206 | while(*ptr && (*ptr != ':')) {
|
---|
207 | *ptr = (char)TOLOWER(*ptr);
|
---|
208 | ptr++;
|
---|
209 | }
|
---|
210 | }
|
---|
211 | return id;
|
---|
212 | }
|
---|
213 |
|
---|
214 | struct hostcache_prune_data {
|
---|
215 | long cache_timeout;
|
---|
216 | time_t now;
|
---|
217 | };
|
---|
218 |
|
---|
219 | /*
|
---|
220 | * This function is set as a callback to be called for every entry in the DNS
|
---|
221 | * cache when we want to prune old unused entries.
|
---|
222 | *
|
---|
223 | * Returning non-zero means remove the entry, return 0 to keep it in the
|
---|
224 | * cache.
|
---|
225 | */
|
---|
226 | static int
|
---|
227 | hostcache_timestamp_remove(void *datap, void *hc)
|
---|
228 | {
|
---|
229 | struct hostcache_prune_data *data =
|
---|
230 | (struct hostcache_prune_data *) datap;
|
---|
231 | struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc;
|
---|
232 |
|
---|
233 | return (0 != c->timestamp)
|
---|
234 | && (data->now - c->timestamp >= data->cache_timeout);
|
---|
235 | }
|
---|
236 |
|
---|
237 | /*
|
---|
238 | * Prune the DNS cache. This assumes that a lock has already been taken.
|
---|
239 | */
|
---|
240 | static void
|
---|
241 | hostcache_prune(struct curl_hash *hostcache, long cache_timeout, time_t now)
|
---|
242 | {
|
---|
243 | struct hostcache_prune_data user;
|
---|
244 |
|
---|
245 | user.cache_timeout = cache_timeout;
|
---|
246 | user.now = now;
|
---|
247 |
|
---|
248 | Curl_hash_clean_with_criterium(hostcache,
|
---|
249 | (void *) &user,
|
---|
250 | hostcache_timestamp_remove);
|
---|
251 | }
|
---|
252 |
|
---|
253 | /*
|
---|
254 | * Library-wide function for pruning the DNS cache. This function takes and
|
---|
255 | * returns the appropriate locks.
|
---|
256 | */
|
---|
257 | void Curl_hostcache_prune(struct Curl_easy *data)
|
---|
258 | {
|
---|
259 | time_t now;
|
---|
260 |
|
---|
261 | if((data->set.dns_cache_timeout == -1) || !data->dns.hostcache)
|
---|
262 | /* cache forever means never prune, and NULL hostcache means
|
---|
263 | we can't do it */
|
---|
264 | return;
|
---|
265 |
|
---|
266 | if(data->share)
|
---|
267 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
268 |
|
---|
269 | time(&now);
|
---|
270 |
|
---|
271 | /* Remove outdated and unused entries from the hostcache */
|
---|
272 | hostcache_prune(data->dns.hostcache,
|
---|
273 | data->set.dns_cache_timeout,
|
---|
274 | now);
|
---|
275 |
|
---|
276 | if(data->share)
|
---|
277 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
278 | }
|
---|
279 |
|
---|
280 | #ifdef HAVE_SIGSETJMP
|
---|
281 | /* Beware this is a global and unique instance. This is used to store the
|
---|
282 | return address that we can jump back to from inside a signal handler. This
|
---|
283 | is not thread-safe stuff. */
|
---|
284 | sigjmp_buf curl_jmpenv;
|
---|
285 | #endif
|
---|
286 |
|
---|
287 | /* lookup address, returns entry if found and not stale */
|
---|
288 | static struct Curl_dns_entry *
|
---|
289 | fetch_addr(struct connectdata *conn,
|
---|
290 | const char *hostname,
|
---|
291 | int port)
|
---|
292 | {
|
---|
293 | char *entry_id = NULL;
|
---|
294 | struct Curl_dns_entry *dns = NULL;
|
---|
295 | size_t entry_len;
|
---|
296 | struct Curl_easy *data = conn->data;
|
---|
297 |
|
---|
298 | /* Create an entry id, based upon the hostname and port */
|
---|
299 | entry_id = create_hostcache_id(hostname, port);
|
---|
300 | /* If we can't create the entry id, fail */
|
---|
301 | if(!entry_id)
|
---|
302 | return dns;
|
---|
303 |
|
---|
304 | entry_len = strlen(entry_id);
|
---|
305 |
|
---|
306 | /* See if its already in our dns cache */
|
---|
307 | dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len + 1);
|
---|
308 |
|
---|
309 | if(dns && (data->set.dns_cache_timeout != -1)) {
|
---|
310 | /* See whether the returned entry is stale. Done before we release lock */
|
---|
311 | struct hostcache_prune_data user;
|
---|
312 |
|
---|
313 | time(&user.now);
|
---|
314 | user.cache_timeout = data->set.dns_cache_timeout;
|
---|
315 |
|
---|
316 | if(hostcache_timestamp_remove(&user, dns)) {
|
---|
317 | infof(data, "Hostname in DNS cache was stale, zapped\n");
|
---|
318 | dns = NULL; /* the memory deallocation is being handled by the hash */
|
---|
319 | Curl_hash_delete(data->dns.hostcache, entry_id, entry_len + 1);
|
---|
320 | }
|
---|
321 | }
|
---|
322 |
|
---|
323 | /* free the allocated entry_id again */
|
---|
324 | free(entry_id);
|
---|
325 |
|
---|
326 | return dns;
|
---|
327 | }
|
---|
328 |
|
---|
329 | /*
|
---|
330 | * Curl_fetch_addr() fetches a 'Curl_dns_entry' already in the DNS cache.
|
---|
331 | *
|
---|
332 | * Curl_resolv() checks initially and multi_runsingle() checks each time
|
---|
333 | * it discovers the handle in the state WAITRESOLVE whether the hostname
|
---|
334 | * has already been resolved and the address has already been stored in
|
---|
335 | * the DNS cache. This short circuits waiting for a lot of pending
|
---|
336 | * lookups for the same hostname requested by different handles.
|
---|
337 | *
|
---|
338 | * Returns the Curl_dns_entry entry pointer or NULL if not in the cache.
|
---|
339 | *
|
---|
340 | * The returned data *MUST* be "unlocked" with Curl_resolv_unlock() after
|
---|
341 | * use, or we'll leak memory!
|
---|
342 | */
|
---|
343 | struct Curl_dns_entry *
|
---|
344 | Curl_fetch_addr(struct connectdata *conn,
|
---|
345 | const char *hostname,
|
---|
346 | int port)
|
---|
347 | {
|
---|
348 | struct Curl_easy *data = conn->data;
|
---|
349 | struct Curl_dns_entry *dns = NULL;
|
---|
350 |
|
---|
351 | if(data->share)
|
---|
352 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
353 |
|
---|
354 | dns = fetch_addr(conn, hostname, port);
|
---|
355 |
|
---|
356 | if(dns)
|
---|
357 | dns->inuse++; /* we use it! */
|
---|
358 |
|
---|
359 | if(data->share)
|
---|
360 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
361 |
|
---|
362 | return dns;
|
---|
363 | }
|
---|
364 |
|
---|
365 | /*
|
---|
366 | * Curl_cache_addr() stores a 'Curl_addrinfo' struct in the DNS cache.
|
---|
367 | *
|
---|
368 | * When calling Curl_resolv() has resulted in a response with a returned
|
---|
369 | * address, we call this function to store the information in the dns
|
---|
370 | * cache etc
|
---|
371 | *
|
---|
372 | * Returns the Curl_dns_entry entry pointer or NULL if the storage failed.
|
---|
373 | */
|
---|
374 | struct Curl_dns_entry *
|
---|
375 | Curl_cache_addr(struct Curl_easy *data,
|
---|
376 | Curl_addrinfo *addr,
|
---|
377 | const char *hostname,
|
---|
378 | int port)
|
---|
379 | {
|
---|
380 | char *entry_id;
|
---|
381 | size_t entry_len;
|
---|
382 | struct Curl_dns_entry *dns;
|
---|
383 | struct Curl_dns_entry *dns2;
|
---|
384 |
|
---|
385 | /* Create an entry id, based upon the hostname and port */
|
---|
386 | entry_id = create_hostcache_id(hostname, port);
|
---|
387 | /* If we can't create the entry id, fail */
|
---|
388 | if(!entry_id)
|
---|
389 | return NULL;
|
---|
390 | entry_len = strlen(entry_id);
|
---|
391 |
|
---|
392 | /* Create a new cache entry */
|
---|
393 | dns = calloc(1, sizeof(struct Curl_dns_entry));
|
---|
394 | if(!dns) {
|
---|
395 | free(entry_id);
|
---|
396 | return NULL;
|
---|
397 | }
|
---|
398 |
|
---|
399 | dns->inuse = 1; /* the cache has the first reference */
|
---|
400 | dns->addr = addr; /* this is the address(es) */
|
---|
401 | time(&dns->timestamp);
|
---|
402 | if(dns->timestamp == 0)
|
---|
403 | dns->timestamp = 1; /* zero indicates CURLOPT_RESOLVE entry */
|
---|
404 |
|
---|
405 | /* Store the resolved data in our DNS cache. */
|
---|
406 | dns2 = Curl_hash_add(data->dns.hostcache, entry_id, entry_len + 1,
|
---|
407 | (void *)dns);
|
---|
408 | if(!dns2) {
|
---|
409 | free(dns);
|
---|
410 | free(entry_id);
|
---|
411 | return NULL;
|
---|
412 | }
|
---|
413 |
|
---|
414 | dns = dns2;
|
---|
415 | dns->inuse++; /* mark entry as in-use */
|
---|
416 |
|
---|
417 | /* free the allocated entry_id */
|
---|
418 | free(entry_id);
|
---|
419 |
|
---|
420 | return dns;
|
---|
421 | }
|
---|
422 |
|
---|
423 | /*
|
---|
424 | * Curl_resolv() is the main name resolve function within libcurl. It resolves
|
---|
425 | * a name and returns a pointer to the entry in the 'entry' argument (if one
|
---|
426 | * is provided). This function might return immediately if we're using asynch
|
---|
427 | * resolves. See the return codes.
|
---|
428 | *
|
---|
429 | * The cache entry we return will get its 'inuse' counter increased when this
|
---|
430 | * function is used. You MUST call Curl_resolv_unlock() later (when you're
|
---|
431 | * done using this struct) to decrease the counter again.
|
---|
432 | *
|
---|
433 | * In debug mode, we specifically test for an interface name "LocalHost"
|
---|
434 | * and resolve "localhost" instead as a means to permit test cases
|
---|
435 | * to connect to a local test server with any host name.
|
---|
436 | *
|
---|
437 | * Return codes:
|
---|
438 | *
|
---|
439 | * CURLRESOLV_ERROR (-1) = error, no pointer
|
---|
440 | * CURLRESOLV_RESOLVED (0) = OK, pointer provided
|
---|
441 | * CURLRESOLV_PENDING (1) = waiting for response, no pointer
|
---|
442 | */
|
---|
443 |
|
---|
444 | int Curl_resolv(struct connectdata *conn,
|
---|
445 | const char *hostname,
|
---|
446 | int port,
|
---|
447 | struct Curl_dns_entry **entry)
|
---|
448 | {
|
---|
449 | struct Curl_dns_entry *dns = NULL;
|
---|
450 | struct Curl_easy *data = conn->data;
|
---|
451 | CURLcode result;
|
---|
452 | int rc = CURLRESOLV_ERROR; /* default to failure */
|
---|
453 |
|
---|
454 | *entry = NULL;
|
---|
455 |
|
---|
456 | if(data->share)
|
---|
457 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
458 |
|
---|
459 | dns = fetch_addr(conn, hostname, port);
|
---|
460 |
|
---|
461 | if(dns) {
|
---|
462 | infof(data, "Hostname %s was found in DNS cache\n", hostname);
|
---|
463 | dns->inuse++; /* we use it! */
|
---|
464 | rc = CURLRESOLV_RESOLVED;
|
---|
465 | }
|
---|
466 |
|
---|
467 | if(data->share)
|
---|
468 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
469 |
|
---|
470 | if(!dns) {
|
---|
471 | /* The entry was not in the cache. Resolve it to IP address */
|
---|
472 |
|
---|
473 | Curl_addrinfo *addr;
|
---|
474 | int respwait;
|
---|
475 |
|
---|
476 | /* Check what IP specifics the app has requested and if we can provide it.
|
---|
477 | * If not, bail out. */
|
---|
478 | if(!Curl_ipvalid(conn))
|
---|
479 | return CURLRESOLV_ERROR;
|
---|
480 |
|
---|
481 | /* If Curl_getaddrinfo() returns NULL, 'respwait' might be set to a
|
---|
482 | non-zero value indicating that we need to wait for the response to the
|
---|
483 | resolve call */
|
---|
484 | addr = Curl_getaddrinfo(conn,
|
---|
485 | #ifdef DEBUGBUILD
|
---|
486 | (data->set.str[STRING_DEVICE]
|
---|
487 | && !strcmp(data->set.str[STRING_DEVICE],
|
---|
488 | "LocalHost"))?"localhost":
|
---|
489 | #endif
|
---|
490 | hostname, port, &respwait);
|
---|
491 |
|
---|
492 | if(!addr) {
|
---|
493 | if(respwait) {
|
---|
494 | /* the response to our resolve call will come asynchronously at
|
---|
495 | a later time, good or bad */
|
---|
496 | /* First, check that we haven't received the info by now */
|
---|
497 | result = Curl_resolver_is_resolved(conn, &dns);
|
---|
498 | if(result) /* error detected */
|
---|
499 | return CURLRESOLV_ERROR;
|
---|
500 | if(dns)
|
---|
501 | rc = CURLRESOLV_RESOLVED; /* pointer provided */
|
---|
502 | else
|
---|
503 | rc = CURLRESOLV_PENDING; /* no info yet */
|
---|
504 | }
|
---|
505 | }
|
---|
506 | else {
|
---|
507 | if(data->share)
|
---|
508 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
509 |
|
---|
510 | /* we got a response, store it in the cache */
|
---|
511 | dns = Curl_cache_addr(data, addr, hostname, port);
|
---|
512 |
|
---|
513 | if(data->share)
|
---|
514 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
515 |
|
---|
516 | if(!dns)
|
---|
517 | /* returned failure, bail out nicely */
|
---|
518 | Curl_freeaddrinfo(addr);
|
---|
519 | else
|
---|
520 | rc = CURLRESOLV_RESOLVED;
|
---|
521 | }
|
---|
522 | }
|
---|
523 |
|
---|
524 | *entry = dns;
|
---|
525 |
|
---|
526 | return rc;
|
---|
527 | }
|
---|
528 |
|
---|
529 | #ifdef USE_ALARM_TIMEOUT
|
---|
530 | /*
|
---|
531 | * This signal handler jumps back into the main libcurl code and continues
|
---|
532 | * execution. This effectively causes the remainder of the application to run
|
---|
533 | * within a signal handler which is nonportable and could lead to problems.
|
---|
534 | */
|
---|
535 | static
|
---|
536 | RETSIGTYPE alarmfunc(int sig)
|
---|
537 | {
|
---|
538 | /* this is for "-ansi -Wall -pedantic" to stop complaining! (rabe) */
|
---|
539 | (void)sig;
|
---|
540 | siglongjmp(curl_jmpenv, 1);
|
---|
541 | }
|
---|
542 | #endif /* USE_ALARM_TIMEOUT */
|
---|
543 |
|
---|
544 | /*
|
---|
545 | * Curl_resolv_timeout() is the same as Curl_resolv() but specifies a
|
---|
546 | * timeout. This function might return immediately if we're using asynch
|
---|
547 | * resolves. See the return codes.
|
---|
548 | *
|
---|
549 | * The cache entry we return will get its 'inuse' counter increased when this
|
---|
550 | * function is used. You MUST call Curl_resolv_unlock() later (when you're
|
---|
551 | * done using this struct) to decrease the counter again.
|
---|
552 | *
|
---|
553 | * If built with a synchronous resolver and use of signals is not
|
---|
554 | * disabled by the application, then a nonzero timeout will cause a
|
---|
555 | * timeout after the specified number of milliseconds. Otherwise, timeout
|
---|
556 | * is ignored.
|
---|
557 | *
|
---|
558 | * Return codes:
|
---|
559 | *
|
---|
560 | * CURLRESOLV_TIMEDOUT(-2) = warning, time too short or previous alarm expired
|
---|
561 | * CURLRESOLV_ERROR (-1) = error, no pointer
|
---|
562 | * CURLRESOLV_RESOLVED (0) = OK, pointer provided
|
---|
563 | * CURLRESOLV_PENDING (1) = waiting for response, no pointer
|
---|
564 | */
|
---|
565 |
|
---|
566 | int Curl_resolv_timeout(struct connectdata *conn,
|
---|
567 | const char *hostname,
|
---|
568 | int port,
|
---|
569 | struct Curl_dns_entry **entry,
|
---|
570 | time_t timeoutms)
|
---|
571 | {
|
---|
572 | #ifdef USE_ALARM_TIMEOUT
|
---|
573 | #ifdef HAVE_SIGACTION
|
---|
574 | struct sigaction keep_sigact; /* store the old struct here */
|
---|
575 | volatile bool keep_copysig = FALSE; /* whether old sigact has been saved */
|
---|
576 | struct sigaction sigact;
|
---|
577 | #else
|
---|
578 | #ifdef HAVE_SIGNAL
|
---|
579 | void (*keep_sigact)(int); /* store the old handler here */
|
---|
580 | #endif /* HAVE_SIGNAL */
|
---|
581 | #endif /* HAVE_SIGACTION */
|
---|
582 | volatile long timeout;
|
---|
583 | volatile unsigned int prev_alarm = 0;
|
---|
584 | struct Curl_easy *data = conn->data;
|
---|
585 | #endif /* USE_ALARM_TIMEOUT */
|
---|
586 | int rc;
|
---|
587 |
|
---|
588 | *entry = NULL;
|
---|
589 |
|
---|
590 | if(timeoutms < 0)
|
---|
591 | /* got an already expired timeout */
|
---|
592 | return CURLRESOLV_TIMEDOUT;
|
---|
593 |
|
---|
594 | #ifdef USE_ALARM_TIMEOUT
|
---|
595 | if(data->set.no_signal)
|
---|
596 | /* Ignore the timeout when signals are disabled */
|
---|
597 | timeout = 0;
|
---|
598 | else
|
---|
599 | timeout = (timeoutms > LONG_MAX) ? LONG_MAX : (long)timeoutms;
|
---|
600 |
|
---|
601 | if(!timeout)
|
---|
602 | /* USE_ALARM_TIMEOUT defined, but no timeout actually requested */
|
---|
603 | return Curl_resolv(conn, hostname, port, entry);
|
---|
604 |
|
---|
605 | if(timeout < 1000) {
|
---|
606 | /* The alarm() function only provides integer second resolution, so if
|
---|
607 | we want to wait less than one second we must bail out already now. */
|
---|
608 | failf(data,
|
---|
609 | "remaining timeout of %ld too small to resolve via SIGALRM method",
|
---|
610 | timeout);
|
---|
611 | return CURLRESOLV_TIMEDOUT;
|
---|
612 | }
|
---|
613 | /* This allows us to time-out from the name resolver, as the timeout
|
---|
614 | will generate a signal and we will siglongjmp() from that here.
|
---|
615 | This technique has problems (see alarmfunc).
|
---|
616 | This should be the last thing we do before calling Curl_resolv(),
|
---|
617 | as otherwise we'd have to worry about variables that get modified
|
---|
618 | before we invoke Curl_resolv() (and thus use "volatile"). */
|
---|
619 | if(sigsetjmp(curl_jmpenv, 1)) {
|
---|
620 | /* this is coming from a siglongjmp() after an alarm signal */
|
---|
621 | failf(data, "name lookup timed out");
|
---|
622 | rc = CURLRESOLV_ERROR;
|
---|
623 | goto clean_up;
|
---|
624 | }
|
---|
625 | else {
|
---|
626 | /*************************************************************
|
---|
627 | * Set signal handler to catch SIGALRM
|
---|
628 | * Store the old value to be able to set it back later!
|
---|
629 | *************************************************************/
|
---|
630 | #ifdef HAVE_SIGACTION
|
---|
631 | sigaction(SIGALRM, NULL, &sigact);
|
---|
632 | keep_sigact = sigact;
|
---|
633 | keep_copysig = TRUE; /* yes, we have a copy */
|
---|
634 | sigact.sa_handler = alarmfunc;
|
---|
635 | #ifdef SA_RESTART
|
---|
636 | /* HPUX doesn't have SA_RESTART but defaults to that behaviour! */
|
---|
637 | sigact.sa_flags &= ~SA_RESTART;
|
---|
638 | #endif
|
---|
639 | /* now set the new struct */
|
---|
640 | sigaction(SIGALRM, &sigact, NULL);
|
---|
641 | #else /* HAVE_SIGACTION */
|
---|
642 | /* no sigaction(), revert to the much lamer signal() */
|
---|
643 | #ifdef HAVE_SIGNAL
|
---|
644 | keep_sigact = signal(SIGALRM, alarmfunc);
|
---|
645 | #endif
|
---|
646 | #endif /* HAVE_SIGACTION */
|
---|
647 |
|
---|
648 | /* alarm() makes a signal get sent when the timeout fires off, and that
|
---|
649 | will abort system calls */
|
---|
650 | prev_alarm = alarm(curlx_sltoui(timeout/1000L));
|
---|
651 | }
|
---|
652 |
|
---|
653 | #else
|
---|
654 | #ifndef CURLRES_ASYNCH
|
---|
655 | if(timeoutms)
|
---|
656 | infof(conn->data, "timeout on name lookup is not supported\n");
|
---|
657 | #else
|
---|
658 | (void)timeoutms; /* timeoutms not used with an async resolver */
|
---|
659 | #endif
|
---|
660 | #endif /* USE_ALARM_TIMEOUT */
|
---|
661 |
|
---|
662 | /* Perform the actual name resolution. This might be interrupted by an
|
---|
663 | * alarm if it takes too long.
|
---|
664 | */
|
---|
665 | rc = Curl_resolv(conn, hostname, port, entry);
|
---|
666 |
|
---|
667 | #ifdef USE_ALARM_TIMEOUT
|
---|
668 | clean_up:
|
---|
669 |
|
---|
670 | if(!prev_alarm)
|
---|
671 | /* deactivate a possibly active alarm before uninstalling the handler */
|
---|
672 | alarm(0);
|
---|
673 |
|
---|
674 | #ifdef HAVE_SIGACTION
|
---|
675 | if(keep_copysig) {
|
---|
676 | /* we got a struct as it looked before, now put that one back nice
|
---|
677 | and clean */
|
---|
678 | sigaction(SIGALRM, &keep_sigact, NULL); /* put it back */
|
---|
679 | }
|
---|
680 | #else
|
---|
681 | #ifdef HAVE_SIGNAL
|
---|
682 | /* restore the previous SIGALRM handler */
|
---|
683 | signal(SIGALRM, keep_sigact);
|
---|
684 | #endif
|
---|
685 | #endif /* HAVE_SIGACTION */
|
---|
686 |
|
---|
687 | /* switch back the alarm() to either zero or to what it was before minus
|
---|
688 | the time we spent until now! */
|
---|
689 | if(prev_alarm) {
|
---|
690 | /* there was an alarm() set before us, now put it back */
|
---|
691 | timediff_t elapsed_secs = Curl_timediff(Curl_now(),
|
---|
692 | conn->created) / 1000;
|
---|
693 |
|
---|
694 | /* the alarm period is counted in even number of seconds */
|
---|
695 | unsigned long alarm_set = prev_alarm - elapsed_secs;
|
---|
696 |
|
---|
697 | if(!alarm_set ||
|
---|
698 | ((alarm_set >= 0x80000000) && (prev_alarm < 0x80000000)) ) {
|
---|
699 | /* if the alarm time-left reached zero or turned "negative" (counted
|
---|
700 | with unsigned values), we should fire off a SIGALRM here, but we
|
---|
701 | won't, and zero would be to switch it off so we never set it to
|
---|
702 | less than 1! */
|
---|
703 | alarm(1);
|
---|
704 | rc = CURLRESOLV_TIMEDOUT;
|
---|
705 | failf(data, "Previous alarm fired off!");
|
---|
706 | }
|
---|
707 | else
|
---|
708 | alarm((unsigned int)alarm_set);
|
---|
709 | }
|
---|
710 | #endif /* USE_ALARM_TIMEOUT */
|
---|
711 |
|
---|
712 | return rc;
|
---|
713 | }
|
---|
714 |
|
---|
715 | /*
|
---|
716 | * Curl_resolv_unlock() unlocks the given cached DNS entry. When this has been
|
---|
717 | * made, the struct may be destroyed due to pruning. It is important that only
|
---|
718 | * one unlock is made for each Curl_resolv() call.
|
---|
719 | *
|
---|
720 | * May be called with 'data' == NULL for global cache.
|
---|
721 | */
|
---|
722 | void Curl_resolv_unlock(struct Curl_easy *data, struct Curl_dns_entry *dns)
|
---|
723 | {
|
---|
724 | if(data && data->share)
|
---|
725 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
726 |
|
---|
727 | freednsentry(dns);
|
---|
728 |
|
---|
729 | if(data && data->share)
|
---|
730 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
731 | }
|
---|
732 |
|
---|
733 | /*
|
---|
734 | * File-internal: release cache dns entry reference, free if inuse drops to 0
|
---|
735 | */
|
---|
736 | static void freednsentry(void *freethis)
|
---|
737 | {
|
---|
738 | struct Curl_dns_entry *dns = (struct Curl_dns_entry *) freethis;
|
---|
739 | DEBUGASSERT(dns && (dns->inuse>0));
|
---|
740 |
|
---|
741 | dns->inuse--;
|
---|
742 | if(dns->inuse == 0) {
|
---|
743 | Curl_freeaddrinfo(dns->addr);
|
---|
744 | free(dns);
|
---|
745 | }
|
---|
746 | }
|
---|
747 |
|
---|
748 | /*
|
---|
749 | * Curl_mk_dnscache() inits a new DNS cache and returns success/failure.
|
---|
750 | */
|
---|
751 | int Curl_mk_dnscache(struct curl_hash *hash)
|
---|
752 | {
|
---|
753 | return Curl_hash_init(hash, 7, Curl_hash_str, Curl_str_key_compare,
|
---|
754 | freednsentry);
|
---|
755 | }
|
---|
756 |
|
---|
757 | /*
|
---|
758 | * Curl_hostcache_clean()
|
---|
759 | *
|
---|
760 | * This _can_ be called with 'data' == NULL but then of course no locking
|
---|
761 | * can be done!
|
---|
762 | */
|
---|
763 |
|
---|
764 | void Curl_hostcache_clean(struct Curl_easy *data,
|
---|
765 | struct curl_hash *hash)
|
---|
766 | {
|
---|
767 | if(data && data->share)
|
---|
768 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
769 |
|
---|
770 | Curl_hash_clean(hash);
|
---|
771 |
|
---|
772 | if(data && data->share)
|
---|
773 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
774 | }
|
---|
775 |
|
---|
776 |
|
---|
777 | CURLcode Curl_loadhostpairs(struct Curl_easy *data)
|
---|
778 | {
|
---|
779 | struct curl_slist *hostp;
|
---|
780 | char hostname[256];
|
---|
781 | int port;
|
---|
782 |
|
---|
783 | for(hostp = data->change.resolve; hostp; hostp = hostp->next) {
|
---|
784 | if(!hostp->data)
|
---|
785 | continue;
|
---|
786 | if(hostp->data[0] == '-') {
|
---|
787 | char *entry_id;
|
---|
788 | size_t entry_len;
|
---|
789 |
|
---|
790 | if(2 != sscanf(hostp->data + 1, "%255[^:]:%d", hostname, &port)) {
|
---|
791 | infof(data, "Couldn't parse CURLOPT_RESOLVE removal entry '%s'!\n",
|
---|
792 | hostp->data);
|
---|
793 | continue;
|
---|
794 | }
|
---|
795 |
|
---|
796 | /* Create an entry id, based upon the hostname and port */
|
---|
797 | entry_id = create_hostcache_id(hostname, port);
|
---|
798 | /* If we can't create the entry id, fail */
|
---|
799 | if(!entry_id) {
|
---|
800 | return CURLE_OUT_OF_MEMORY;
|
---|
801 | }
|
---|
802 |
|
---|
803 | entry_len = strlen(entry_id);
|
---|
804 |
|
---|
805 | if(data->share)
|
---|
806 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
807 |
|
---|
808 | /* delete entry, ignore if it didn't exist */
|
---|
809 | Curl_hash_delete(data->dns.hostcache, entry_id, entry_len + 1);
|
---|
810 |
|
---|
811 | if(data->share)
|
---|
812 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
813 |
|
---|
814 | /* free the allocated entry_id again */
|
---|
815 | free(entry_id);
|
---|
816 | }
|
---|
817 | else {
|
---|
818 | struct Curl_dns_entry *dns;
|
---|
819 | Curl_addrinfo *addr;
|
---|
820 | char *entry_id;
|
---|
821 | size_t entry_len;
|
---|
822 | char buffer[256];
|
---|
823 | char *address = &buffer[0];
|
---|
824 |
|
---|
825 | if(3 != sscanf(hostp->data, "%255[^:]:%d:%255s", hostname, &port,
|
---|
826 | address)) {
|
---|
827 | infof(data, "Couldn't parse CURLOPT_RESOLVE entry '%s'!\n",
|
---|
828 | hostp->data);
|
---|
829 | continue;
|
---|
830 | }
|
---|
831 |
|
---|
832 | /* allow IP(v6) address within [brackets] */
|
---|
833 | if(address[0] == '[') {
|
---|
834 | size_t alen = strlen(address);
|
---|
835 | if(address[alen-1] != ']')
|
---|
836 | /* it needs to also end with ] to be valid */
|
---|
837 | continue;
|
---|
838 | address[alen-1] = 0; /* zero terminate there */
|
---|
839 | address++; /* pass the open bracket */
|
---|
840 | }
|
---|
841 |
|
---|
842 | addr = Curl_str2addr(address, port);
|
---|
843 | if(!addr) {
|
---|
844 | infof(data, "Address in '%s' found illegal!\n", hostp->data);
|
---|
845 | continue;
|
---|
846 | }
|
---|
847 |
|
---|
848 | /* Create an entry id, based upon the hostname and port */
|
---|
849 | entry_id = create_hostcache_id(hostname, port);
|
---|
850 | /* If we can't create the entry id, fail */
|
---|
851 | if(!entry_id) {
|
---|
852 | Curl_freeaddrinfo(addr);
|
---|
853 | return CURLE_OUT_OF_MEMORY;
|
---|
854 | }
|
---|
855 |
|
---|
856 | entry_len = strlen(entry_id);
|
---|
857 |
|
---|
858 | if(data->share)
|
---|
859 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
860 |
|
---|
861 | /* See if its already in our dns cache */
|
---|
862 | dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len + 1);
|
---|
863 |
|
---|
864 | /* free the allocated entry_id again */
|
---|
865 | free(entry_id);
|
---|
866 |
|
---|
867 | if(!dns) {
|
---|
868 | /* if not in the cache already, put this host in the cache */
|
---|
869 | dns = Curl_cache_addr(data, addr, hostname, port);
|
---|
870 | if(dns) {
|
---|
871 | dns->timestamp = 0; /* mark as added by CURLOPT_RESOLVE */
|
---|
872 | /* release the returned reference; the cache itself will keep the
|
---|
873 | * entry alive: */
|
---|
874 | dns->inuse--;
|
---|
875 | }
|
---|
876 | }
|
---|
877 | else
|
---|
878 | /* this is a duplicate, free it again */
|
---|
879 | Curl_freeaddrinfo(addr);
|
---|
880 |
|
---|
881 | if(data->share)
|
---|
882 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
883 |
|
---|
884 | if(!dns) {
|
---|
885 | Curl_freeaddrinfo(addr);
|
---|
886 | return CURLE_OUT_OF_MEMORY;
|
---|
887 | }
|
---|
888 | infof(data, "Added %s:%d:%s to DNS cache\n",
|
---|
889 | hostname, port, address);
|
---|
890 | }
|
---|
891 | }
|
---|
892 | data->change.resolve = NULL; /* dealt with now */
|
---|
893 |
|
---|
894 | return CURLE_OK;
|
---|
895 | }
|
---|