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1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) 1998 - 2016, 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 #if defined(USE_THREADS_POSIX)
40 #  ifdef HAVE_PTHREAD_H
41 #    include <pthread.h>
42 #  endif
43 #elif defined(USE_THREADS_WIN32)
44 #  ifdef HAVE_PROCESS_H
45 #    include <process.h>
46 #  endif
47 #endif
48 
49 #if (defined(NETWARE) && defined(__NOVELL_LIBC__))
50 #undef in_addr_t
51 #define in_addr_t unsigned long
52 #endif
53 
54 #ifdef HAVE_GETADDRINFO
55 #  define RESOLVER_ENOMEM  EAI_MEMORY
56 #else
57 #  define RESOLVER_ENOMEM  ENOMEM
58 #endif
59 
60 #include "urldata.h"
61 #include "sendf.h"
62 #include "hostip.h"
63 #include "hash.h"
64 #include "share.h"
65 #include "strerror.h"
66 #include "url.h"
67 #include "multiif.h"
68 #include "inet_pton.h"
69 #include "inet_ntop.h"
70 #include "curl_threads.h"
71 #include "connect.h"
72 /* The last 3 #include files should be in this order */
73 #include "curl_printf.h"
74 #include "curl_memory.h"
75 #include "memdebug.h"
76 
77 /***********************************************************************
78  * Only for threaded name resolves builds
79  **********************************************************************/
80 #ifdef CURLRES_THREADED
81 
82 /*
83  * Curl_resolver_global_init()
84  * Called from curl_global_init() to initialize global resolver environment.
85  * Does nothing here.
86  */
Curl_resolver_global_init(void)87 int Curl_resolver_global_init(void)
88 {
89   return CURLE_OK;
90 }
91 
92 /*
93  * Curl_resolver_global_cleanup()
94  * Called from curl_global_cleanup() to destroy global resolver environment.
95  * Does nothing here.
96  */
Curl_resolver_global_cleanup(void)97 void Curl_resolver_global_cleanup(void)
98 {
99 }
100 
101 /*
102  * Curl_resolver_init()
103  * Called from curl_easy_init() -> Curl_open() to initialize resolver
104  * URL-state specific environment ('resolver' member of the UrlState
105  * structure).  Does nothing here.
106  */
Curl_resolver_init(void ** resolver)107 CURLcode Curl_resolver_init(void **resolver)
108 {
109   (void)resolver;
110   return CURLE_OK;
111 }
112 
113 /*
114  * Curl_resolver_cleanup()
115  * Called from curl_easy_cleanup() -> Curl_close() to cleanup resolver
116  * URL-state specific environment ('resolver' member of the UrlState
117  * structure).  Does nothing here.
118  */
Curl_resolver_cleanup(void * resolver)119 void Curl_resolver_cleanup(void *resolver)
120 {
121   (void)resolver;
122 }
123 
124 /*
125  * Curl_resolver_duphandle()
126  * Called from curl_easy_duphandle() to duplicate resolver URL state-specific
127  * environment ('resolver' member of the UrlState structure).  Does nothing
128  * here.
129  */
Curl_resolver_duphandle(void ** to,void * from)130 int Curl_resolver_duphandle(void **to, void *from)
131 {
132   (void)to;
133   (void)from;
134   return CURLE_OK;
135 }
136 
137 static void destroy_async_data(struct Curl_async *);
138 
139 /*
140  * Cancel all possibly still on-going resolves for this connection.
141  */
Curl_resolver_cancel(struct connectdata * conn)142 void Curl_resolver_cancel(struct connectdata *conn)
143 {
144   destroy_async_data(&conn->async);
145 }
146 
147 /* This function is used to init a threaded resolve */
148 static bool init_resolve_thread(struct connectdata *conn,
149                                 const char *hostname, int port,
150                                 const struct addrinfo *hints);
151 
152 
153 /* Data for synchronization between resolver thread and its parent */
154 struct thread_sync_data {
155   curl_mutex_t * mtx;
156   int done;
157 
158   char *hostname;        /* hostname to resolve, Curl_async.hostname
159                             duplicate */
160   int port;
161   int sock_error;
162   Curl_addrinfo *res;
163 #ifdef HAVE_GETADDRINFO
164   struct addrinfo hints;
165 #endif
166   struct thread_data *td; /* for thread-self cleanup */
167 };
168 
169 struct thread_data {
170   curl_thread_t thread_hnd;
171   unsigned int poll_interval;
172   time_t interval_end;
173   struct thread_sync_data tsd;
174 };
175 
conn_thread_sync_data(struct connectdata * conn)176 static struct thread_sync_data *conn_thread_sync_data(struct connectdata *conn)
177 {
178   return &(((struct thread_data *)conn->async.os_specific)->tsd);
179 }
180 
181 #define CONN_THREAD_SYNC_DATA(conn) &(((conn)->async.os_specific)->tsd);
182 
183 /* Destroy resolver thread synchronization data */
184 static
destroy_thread_sync_data(struct thread_sync_data * tsd)185 void destroy_thread_sync_data(struct thread_sync_data * tsd)
186 {
187   if(tsd->mtx) {
188     Curl_mutex_destroy(tsd->mtx);
189     free(tsd->mtx);
190   }
191 
192   free(tsd->hostname);
193 
194   if(tsd->res)
195     Curl_freeaddrinfo(tsd->res);
196 
197   memset(tsd, 0, sizeof(*tsd));
198 }
199 
200 /* Initialize resolver thread synchronization data */
201 static
init_thread_sync_data(struct thread_data * td,const char * hostname,int port,const struct addrinfo * hints)202 int init_thread_sync_data(struct thread_data * td,
203                            const char *hostname,
204                            int port,
205                            const struct addrinfo *hints)
206 {
207   struct thread_sync_data *tsd = &td->tsd;
208 
209   memset(tsd, 0, sizeof(*tsd));
210 
211   tsd->td = td;
212   tsd->port = port;
213 #ifdef HAVE_GETADDRINFO
214   DEBUGASSERT(hints);
215   tsd->hints = *hints;
216 #else
217   (void) hints;
218 #endif
219 
220   tsd->mtx = malloc(sizeof(curl_mutex_t));
221   if(tsd->mtx == NULL)
222     goto err_exit;
223 
224   Curl_mutex_init(tsd->mtx);
225 
226   tsd->sock_error = CURL_ASYNC_SUCCESS;
227 
228   /* Copying hostname string because original can be destroyed by parent
229    * thread during gethostbyname execution.
230    */
231   tsd->hostname = strdup(hostname);
232   if(!tsd->hostname)
233     goto err_exit;
234 
235   return 1;
236 
237  err_exit:
238   /* Memory allocation failed */
239   destroy_thread_sync_data(tsd);
240   return 0;
241 }
242 
getaddrinfo_complete(struct connectdata * conn)243 static int getaddrinfo_complete(struct connectdata *conn)
244 {
245   struct thread_sync_data *tsd = conn_thread_sync_data(conn);
246   int rc;
247 
248   rc = Curl_addrinfo_callback(conn, tsd->sock_error, tsd->res);
249   /* The tsd->res structure has been copied to async.dns and perhaps the DNS
250      cache.  Set our copy to NULL so destroy_thread_sync_data doesn't free it.
251   */
252   tsd->res = NULL;
253 
254   return rc;
255 }
256 
257 
258 #ifdef HAVE_GETADDRINFO
259 
260 /*
261  * getaddrinfo_thread() resolves a name and then exits.
262  *
263  * For builds without ARES, but with ENABLE_IPV6, create a resolver thread
264  * and wait on it.
265  */
getaddrinfo_thread(void * arg)266 static unsigned int CURL_STDCALL getaddrinfo_thread (void *arg)
267 {
268   struct thread_sync_data *tsd = (struct thread_sync_data*)arg;
269   struct thread_data *td = tsd->td;
270   char service[12];
271   int rc;
272 
273   snprintf(service, sizeof(service), "%d", tsd->port);
274 
275   rc = Curl_getaddrinfo_ex(tsd->hostname, service, &tsd->hints, &tsd->res);
276 
277   if(rc != 0) {
278     tsd->sock_error = SOCKERRNO?SOCKERRNO:rc;
279     if(tsd->sock_error == 0)
280       tsd->sock_error = RESOLVER_ENOMEM;
281   }
282   else {
283     Curl_addrinfo_set_port(tsd->res, tsd->port);
284   }
285 
286   Curl_mutex_acquire(tsd->mtx);
287   if(tsd->done) {
288     /* too late, gotta clean up the mess */
289     Curl_mutex_release(tsd->mtx);
290     destroy_thread_sync_data(tsd);
291     free(td);
292   }
293   else {
294     tsd->done = 1;
295     Curl_mutex_release(tsd->mtx);
296   }
297 
298   return 0;
299 }
300 
301 #else /* HAVE_GETADDRINFO */
302 
303 /*
304  * gethostbyname_thread() resolves a name and then exits.
305  */
gethostbyname_thread(void * arg)306 static unsigned int CURL_STDCALL gethostbyname_thread (void *arg)
307 {
308   struct thread_sync_data *tsd = (struct thread_sync_data *)arg;
309   struct thread_data *td = tsd->td;
310 
311   tsd->res = Curl_ipv4_resolve_r(tsd->hostname, tsd->port);
312 
313   if(!tsd->res) {
314     tsd->sock_error = SOCKERRNO;
315     if(tsd->sock_error == 0)
316       tsd->sock_error = RESOLVER_ENOMEM;
317   }
318 
319   Curl_mutex_acquire(tsd->mtx);
320   if(tsd->done) {
321     /* too late, gotta clean up the mess */
322     Curl_mutex_release(tsd->mtx);
323     destroy_thread_sync_data(tsd);
324     free(td);
325   }
326   else {
327     tsd->done = 1;
328     Curl_mutex_release(tsd->mtx);
329   }
330 
331   return 0;
332 }
333 
334 #endif /* HAVE_GETADDRINFO */
335 
336 /*
337  * destroy_async_data() cleans up async resolver data and thread handle.
338  */
destroy_async_data(struct Curl_async * async)339 static void destroy_async_data (struct Curl_async *async)
340 {
341   if(async->os_specific) {
342     struct thread_data *td = (struct thread_data*) async->os_specific;
343     int done;
344 
345     /*
346      * if the thread is still blocking in the resolve syscall, detach it and
347      * let the thread do the cleanup...
348      */
349     Curl_mutex_acquire(td->tsd.mtx);
350     done = td->tsd.done;
351     td->tsd.done = 1;
352     Curl_mutex_release(td->tsd.mtx);
353 
354     if(!done) {
355       Curl_thread_destroy(td->thread_hnd);
356     }
357     else {
358       if(td->thread_hnd != curl_thread_t_null)
359         Curl_thread_join(&td->thread_hnd);
360 
361       destroy_thread_sync_data(&td->tsd);
362 
363       free(async->os_specific);
364     }
365   }
366   async->os_specific = NULL;
367 
368   free(async->hostname);
369   async->hostname = NULL;
370 }
371 
372 /*
373  * init_resolve_thread() starts a new thread that performs the actual
374  * resolve. This function returns before the resolve is done.
375  *
376  * Returns FALSE in case of failure, otherwise TRUE.
377  */
init_resolve_thread(struct connectdata * conn,const char * hostname,int port,const struct addrinfo * hints)378 static bool init_resolve_thread (struct connectdata *conn,
379                                  const char *hostname, int port,
380                                  const struct addrinfo *hints)
381 {
382   struct thread_data *td = calloc(1, sizeof(struct thread_data));
383   int err = RESOLVER_ENOMEM;
384 
385   conn->async.os_specific = (void *)td;
386   if(!td)
387     goto err_exit;
388 
389   conn->async.port = port;
390   conn->async.done = FALSE;
391   conn->async.status = 0;
392   conn->async.dns = NULL;
393   td->thread_hnd = curl_thread_t_null;
394 
395   if(!init_thread_sync_data(td, hostname, port, hints))
396     goto err_exit;
397 
398   free(conn->async.hostname);
399   conn->async.hostname = strdup(hostname);
400   if(!conn->async.hostname)
401     goto err_exit;
402 
403 #ifdef HAVE_GETADDRINFO
404   td->thread_hnd = Curl_thread_create(getaddrinfo_thread, &td->tsd);
405 #else
406   td->thread_hnd = Curl_thread_create(gethostbyname_thread, &td->tsd);
407 #endif
408 
409   if(!td->thread_hnd) {
410 #ifndef _WIN32_WCE
411     err = errno;
412 #endif
413     goto err_exit;
414   }
415 
416   return TRUE;
417 
418  err_exit:
419   destroy_async_data(&conn->async);
420 
421   SET_ERRNO(err);
422 
423   return FALSE;
424 }
425 
426 /*
427  * resolver_error() calls failf() with the appropriate message after a resolve
428  * error
429  */
430 
resolver_error(struct connectdata * conn)431 static CURLcode resolver_error(struct connectdata *conn)
432 {
433   const char *host_or_proxy;
434   CURLcode result;
435 
436   if(conn->bits.httpproxy) {
437     host_or_proxy = "proxy";
438     result = CURLE_COULDNT_RESOLVE_PROXY;
439   }
440   else {
441     host_or_proxy = "host";
442     result = CURLE_COULDNT_RESOLVE_HOST;
443   }
444 
445   failf(conn->data, "Could not resolve %s: %s", host_or_proxy,
446         conn->async.hostname);
447 
448   return result;
449 }
450 
451 /*
452  * Curl_resolver_wait_resolv()
453  *
454  * waits for a resolve to finish. This function should be avoided since using
455  * this risk getting the multi interface to "hang".
456  *
457  * If 'entry' is non-NULL, make it point to the resolved dns entry
458  *
459  * This is the version for resolves-in-a-thread.
460  */
Curl_resolver_wait_resolv(struct connectdata * conn,struct Curl_dns_entry ** entry)461 CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
462                                    struct Curl_dns_entry **entry)
463 {
464   struct thread_data   *td = (struct thread_data*) conn->async.os_specific;
465   CURLcode result = CURLE_OK;
466 
467   DEBUGASSERT(conn && td);
468 
469   /* wait for the thread to resolve the name */
470   if(Curl_thread_join(&td->thread_hnd))
471     result = getaddrinfo_complete(conn);
472   else
473     DEBUGASSERT(0);
474 
475   conn->async.done = TRUE;
476 
477   if(entry)
478     *entry = conn->async.dns;
479 
480   if(!conn->async.dns)
481     /* a name was not resolved, report error */
482     result = resolver_error(conn);
483 
484   destroy_async_data(&conn->async);
485 
486   if(!conn->async.dns)
487     connclose(conn, "asynch resolve failed");
488 
489   return result;
490 }
491 
492 /*
493  * Curl_resolver_is_resolved() is called repeatedly to check if a previous
494  * name resolve request has completed. It should also make sure to time-out if
495  * the operation seems to take too long.
496  */
Curl_resolver_is_resolved(struct connectdata * conn,struct Curl_dns_entry ** entry)497 CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
498                                    struct Curl_dns_entry **entry)
499 {
500   struct Curl_easy *data = conn->data;
501   struct thread_data   *td = (struct thread_data*) conn->async.os_specific;
502   int done = 0;
503 
504   *entry = NULL;
505 
506   if(!td) {
507     DEBUGASSERT(td);
508     return CURLE_COULDNT_RESOLVE_HOST;
509   }
510 
511   Curl_mutex_acquire(td->tsd.mtx);
512   done = td->tsd.done;
513   Curl_mutex_release(td->tsd.mtx);
514 
515   if(done) {
516     getaddrinfo_complete(conn);
517 
518     if(!conn->async.dns) {
519       CURLcode result = resolver_error(conn);
520       destroy_async_data(&conn->async);
521       return result;
522     }
523     destroy_async_data(&conn->async);
524     *entry = conn->async.dns;
525   }
526   else {
527     /* poll for name lookup done with exponential backoff up to 250ms */
528     time_t elapsed = Curl_tvdiff(Curl_tvnow(), data->progress.t_startsingle);
529     if(elapsed < 0)
530       elapsed = 0;
531 
532     if(td->poll_interval == 0)
533       /* Start at 1ms poll interval */
534       td->poll_interval = 1;
535     else if(elapsed >= td->interval_end)
536       /* Back-off exponentially if last interval expired  */
537       td->poll_interval *= 2;
538 
539     if(td->poll_interval > 250)
540       td->poll_interval = 250;
541 
542     td->interval_end = elapsed + td->poll_interval;
543     Curl_expire(conn->data, td->poll_interval);
544   }
545 
546   return CURLE_OK;
547 }
548 
Curl_resolver_getsock(struct connectdata * conn,curl_socket_t * socks,int numsocks)549 int Curl_resolver_getsock(struct connectdata *conn,
550                           curl_socket_t *socks,
551                           int numsocks)
552 {
553   (void)conn;
554   (void)socks;
555   (void)numsocks;
556   return 0;
557 }
558 
559 #ifndef HAVE_GETADDRINFO
560 /*
561  * Curl_getaddrinfo() - for platforms without getaddrinfo
562  */
Curl_resolver_getaddrinfo(struct connectdata * conn,const char * hostname,int port,int * waitp)563 Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
564                                          const char *hostname,
565                                          int port,
566                                          int *waitp)
567 {
568   struct in_addr in;
569 
570   *waitp = 0; /* default to synchronous response */
571 
572   if(Curl_inet_pton(AF_INET, hostname, &in) > 0)
573     /* This is a dotted IP address 123.123.123.123-style */
574     return Curl_ip2addr(AF_INET, &in, hostname, port);
575 
576   /* fire up a new resolver thread! */
577   if(init_resolve_thread(conn, hostname, port, NULL)) {
578     *waitp = 1; /* expect asynchronous response */
579     return NULL;
580   }
581 
582   /* fall-back to blocking version */
583   return Curl_ipv4_resolve_r(hostname, port);
584 }
585 
586 #else /* !HAVE_GETADDRINFO */
587 
588 /*
589  * Curl_resolver_getaddrinfo() - for getaddrinfo
590  */
Curl_resolver_getaddrinfo(struct connectdata * conn,const char * hostname,int port,int * waitp)591 Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
592                                          const char *hostname,
593                                          int port,
594                                          int *waitp)
595 {
596   struct addrinfo hints;
597   struct in_addr in;
598   Curl_addrinfo *res;
599   int error;
600   char sbuf[12];
601   int pf = PF_INET;
602 #ifdef CURLRES_IPV6
603   struct in6_addr in6;
604 #endif /* CURLRES_IPV6 */
605 
606   *waitp = 0; /* default to synchronous response */
607 
608 #ifndef USE_RESOLVE_ON_IPS
609   /* First check if this is an IPv4 address string */
610   if(Curl_inet_pton(AF_INET, hostname, &in) > 0)
611     /* This is a dotted IP address 123.123.123.123-style */
612     return Curl_ip2addr(AF_INET, &in, hostname, port);
613 
614 #ifdef CURLRES_IPV6
615   /* check if this is an IPv6 address string */
616   if(Curl_inet_pton(AF_INET6, hostname, &in6) > 0)
617     /* This is an IPv6 address literal */
618     return Curl_ip2addr(AF_INET6, &in6, hostname, port);
619 #endif /* CURLRES_IPV6 */
620 #endif /* !USE_RESOLVE_ON_IPS */
621 
622 #ifdef CURLRES_IPV6
623   /*
624    * Check if a limited name resolve has been requested.
625    */
626   switch(conn->ip_version) {
627   case CURL_IPRESOLVE_V4:
628     pf = PF_INET;
629     break;
630   case CURL_IPRESOLVE_V6:
631     pf = PF_INET6;
632     break;
633   default:
634     pf = PF_UNSPEC;
635     break;
636   }
637 
638   if((pf != PF_INET) && !Curl_ipv6works())
639     /* The stack seems to be a non-IPv6 one */
640     pf = PF_INET;
641 #endif /* CURLRES_IPV6 */
642 
643   memset(&hints, 0, sizeof(hints));
644   hints.ai_family = pf;
645   hints.ai_socktype = conn->socktype;
646 
647   snprintf(sbuf, sizeof(sbuf), "%d", port);
648 
649   /* fire up a new resolver thread! */
650   if(init_resolve_thread(conn, hostname, port, &hints)) {
651     *waitp = 1; /* expect asynchronous response */
652     return NULL;
653   }
654 
655   /* fall-back to blocking version */
656   infof(conn->data, "init_resolve_thread() failed for %s; %s\n",
657         hostname, Curl_strerror(conn, ERRNO));
658 
659   error = Curl_getaddrinfo_ex(hostname, sbuf, &hints, &res);
660   if(error) {
661     infof(conn->data, "getaddrinfo() failed for %s:%d; %s\n",
662           hostname, port, Curl_strerror(conn, SOCKERRNO));
663     return NULL;
664   }
665   else {
666     Curl_addrinfo_set_port(res, port);
667   }
668 
669   return res;
670 }
671 
672 #endif /* !HAVE_GETADDRINFO */
673 
Curl_set_dns_servers(struct Curl_easy * data,char * servers)674 CURLcode Curl_set_dns_servers(struct Curl_easy *data,
675                               char *servers)
676 {
677   (void)data;
678   (void)servers;
679   return CURLE_NOT_BUILT_IN;
680 
681 }
682 
Curl_set_dns_interface(struct Curl_easy * data,const char * interf)683 CURLcode Curl_set_dns_interface(struct Curl_easy *data,
684                                 const char *interf)
685 {
686   (void)data;
687   (void)interf;
688   return CURLE_NOT_BUILT_IN;
689 }
690 
Curl_set_dns_local_ip4(struct Curl_easy * data,const char * local_ip4)691 CURLcode Curl_set_dns_local_ip4(struct Curl_easy *data,
692                                 const char *local_ip4)
693 {
694   (void)data;
695   (void)local_ip4;
696   return CURLE_NOT_BUILT_IN;
697 }
698 
Curl_set_dns_local_ip6(struct Curl_easy * data,const char * local_ip6)699 CURLcode Curl_set_dns_local_ip6(struct Curl_easy *data,
700                                 const char *local_ip6)
701 {
702   (void)data;
703   (void)local_ip6;
704   return CURLE_NOT_BUILT_IN;
705 }
706 
707 #endif /* CURLRES_THREADED */
708