source: UsbWattMeter/trunk/curl-7.47.1/lib/asyn-ares.c

Last change on this file was 167, checked in by coas-nagasima, 8 years ago

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1/***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2015, 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_LIMITS_H
26#include <limits.h>
27#endif
28#ifdef HAVE_NETINET_IN_H
29#include <netinet/in.h>
30#endif
31#ifdef HAVE_NETDB_H
32#include <netdb.h>
33#endif
34#ifdef HAVE_ARPA_INET_H
35#include <arpa/inet.h>
36#endif
37#ifdef __VMS
38#include <in.h>
39#include <inet.h>
40#endif
41
42#ifdef HAVE_PROCESS_H
43#include <process.h>
44#endif
45
46#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
47#undef in_addr_t
48#define in_addr_t unsigned long
49#endif
50
51/***********************************************************************
52 * Only for ares-enabled builds
53 * And only for functions that fulfill the asynch resolver backend API
54 * as defined in asyn.h, nothing else belongs in this file!
55 **********************************************************************/
56
57#ifdef CURLRES_ARES
58
59#include "urldata.h"
60#include "sendf.h"
61#include "hostip.h"
62#include "hash.h"
63#include "share.h"
64#include "strerror.h"
65#include "url.h"
66#include "multiif.h"
67#include "inet_pton.h"
68#include "connect.h"
69#include "select.h"
70#include "progress.h"
71#include "curl_printf.h"
72
73# if defined(CURL_STATICLIB) && !defined(CARES_STATICLIB) && \
74 (defined(WIN32) || defined(_WIN32) || defined(__SYMBIAN32__))
75# define CARES_STATICLIB
76# endif
77# include <ares.h>
78# include <ares_version.h> /* really old c-ares didn't include this by
79 itself */
80
81#if ARES_VERSION >= 0x010500
82/* c-ares 1.5.0 or later, the callback proto is modified */
83#define HAVE_CARES_CALLBACK_TIMEOUTS 1
84#endif
85
86#include "curl_memory.h"
87/* The last #include file should be: */
88#include "memdebug.h"
89
90struct ResolverResults {
91 int num_pending; /* number of ares_gethostbyname() requests */
92 Curl_addrinfo *temp_ai; /* intermediary result while fetching c-ares parts */
93 int last_status;
94};
95
96/*
97 * Curl_resolver_global_init() - the generic low-level asynchronous name
98 * resolve API. Called from curl_global_init() to initialize global resolver
99 * environment. Initializes ares library.
100 */
101int Curl_resolver_global_init(void)
102{
103#ifdef CARES_HAVE_ARES_LIBRARY_INIT
104 if(ares_library_init(ARES_LIB_INIT_ALL)) {
105 return CURLE_FAILED_INIT;
106 }
107#endif
108 return CURLE_OK;
109}
110
111/*
112 * Curl_resolver_global_cleanup()
113 *
114 * Called from curl_global_cleanup() to destroy global resolver environment.
115 * Deinitializes ares library.
116 */
117void Curl_resolver_global_cleanup(void)
118{
119#ifdef CARES_HAVE_ARES_LIBRARY_CLEANUP
120 ares_library_cleanup();
121#endif
122}
123
124/*
125 * Curl_resolver_init()
126 *
127 * Called from curl_easy_init() -> Curl_open() to initialize resolver
128 * URL-state specific environment ('resolver' member of the UrlState
129 * structure). Fills the passed pointer by the initialized ares_channel.
130 */
131CURLcode Curl_resolver_init(void **resolver)
132{
133 int status = ares_init((ares_channel*)resolver);
134 if(status != ARES_SUCCESS) {
135 if(status == ARES_ENOMEM)
136 return CURLE_OUT_OF_MEMORY;
137 else
138 return CURLE_FAILED_INIT;
139 }
140 return CURLE_OK;
141 /* make sure that all other returns from this function should destroy the
142 ares channel before returning error! */
143}
144
145/*
146 * Curl_resolver_cleanup()
147 *
148 * Called from curl_easy_cleanup() -> Curl_close() to cleanup resolver
149 * URL-state specific environment ('resolver' member of the UrlState
150 * structure). Destroys the ares channel.
151 */
152void Curl_resolver_cleanup(void *resolver)
153{
154 ares_destroy((ares_channel)resolver);
155}
156
157/*
158 * Curl_resolver_duphandle()
159 *
160 * Called from curl_easy_duphandle() to duplicate resolver URL-state specific
161 * environment ('resolver' member of the UrlState structure). Duplicates the
162 * 'from' ares channel and passes the resulting channel to the 'to' pointer.
163 */
164int Curl_resolver_duphandle(void **to, void *from)
165{
166 /* Clone the ares channel for the new handle */
167 if(ARES_SUCCESS != ares_dup((ares_channel*)to, (ares_channel)from))
168 return CURLE_FAILED_INIT;
169 return CURLE_OK;
170}
171
172static void destroy_async_data (struct Curl_async *async);
173
174/*
175 * Cancel all possibly still on-going resolves for this connection.
176 */
177void Curl_resolver_cancel(struct connectdata *conn)
178{
179 if(conn->data && conn->data->state.resolver)
180 ares_cancel((ares_channel)conn->data->state.resolver);
181 destroy_async_data(&conn->async);
182}
183
184/*
185 * destroy_async_data() cleans up async resolver data.
186 */
187static void destroy_async_data (struct Curl_async *async)
188{
189 free(async->hostname);
190
191 if(async->os_specific) {
192 struct ResolverResults *res = (struct ResolverResults *)async->os_specific;
193 if(res) {
194 if(res->temp_ai) {
195 Curl_freeaddrinfo(res->temp_ai);
196 res->temp_ai = NULL;
197 }
198 free(res);
199 }
200 async->os_specific = NULL;
201 }
202
203 async->hostname = NULL;
204}
205
206/*
207 * Curl_resolver_getsock() is called when someone from the outside world
208 * (using curl_multi_fdset()) wants to get our fd_set setup and we're talking
209 * with ares. The caller must make sure that this function is only called when
210 * we have a working ares channel.
211 *
212 * Returns: sockets-in-use-bitmap
213 */
214
215int Curl_resolver_getsock(struct connectdata *conn,
216 curl_socket_t *socks,
217 int numsocks)
218
219{
220 struct timeval maxtime;
221 struct timeval timebuf;
222 struct timeval *timeout;
223 long milli;
224 int max = ares_getsock((ares_channel)conn->data->state.resolver,
225 (ares_socket_t *)socks, numsocks);
226
227 maxtime.tv_sec = CURL_TIMEOUT_RESOLVE;
228 maxtime.tv_usec = 0;
229
230 timeout = ares_timeout((ares_channel)conn->data->state.resolver, &maxtime,
231 &timebuf);
232 milli = (timeout->tv_sec * 1000) + (timeout->tv_usec/1000);
233 if(milli == 0)
234 milli += 10;
235 Curl_expire_latest(conn->data, milli);
236
237 return max;
238}
239
240/*
241 * waitperform()
242 *
243 * 1) Ask ares what sockets it currently plays with, then
244 * 2) wait for the timeout period to check for action on ares' sockets.
245 * 3) tell ares to act on all the sockets marked as "with action"
246 *
247 * return number of sockets it worked on
248 */
249
250static int waitperform(struct connectdata *conn, int timeout_ms)
251{
252 struct SessionHandle *data = conn->data;
253 int nfds;
254 int bitmask;
255 ares_socket_t socks[ARES_GETSOCK_MAXNUM];
256 struct pollfd pfd[ARES_GETSOCK_MAXNUM];
257 int i;
258 int num = 0;
259
260 bitmask = ares_getsock((ares_channel)data->state.resolver, socks,
261 ARES_GETSOCK_MAXNUM);
262
263 for(i=0; i < ARES_GETSOCK_MAXNUM; i++) {
264 pfd[i].events = 0;
265 pfd[i].revents = 0;
266 if(ARES_GETSOCK_READABLE(bitmask, i)) {
267 pfd[i].fd = socks[i];
268 pfd[i].events |= POLLRDNORM|POLLIN;
269 }
270 if(ARES_GETSOCK_WRITABLE(bitmask, i)) {
271 pfd[i].fd = socks[i];
272 pfd[i].events |= POLLWRNORM|POLLOUT;
273 }
274 if(pfd[i].events != 0)
275 num++;
276 else
277 break;
278 }
279
280 if(num)
281 nfds = Curl_poll(pfd, num, timeout_ms);
282 else
283 nfds = 0;
284
285 if(!nfds)
286 /* Call ares_process() unconditonally here, even if we simply timed out
287 above, as otherwise the ares name resolve won't timeout! */
288 ares_process_fd((ares_channel)data->state.resolver, ARES_SOCKET_BAD,
289 ARES_SOCKET_BAD);
290 else {
291 /* move through the descriptors and ask for processing on them */
292 for(i=0; i < num; i++)
293 ares_process_fd((ares_channel)data->state.resolver,
294 pfd[i].revents & (POLLRDNORM|POLLIN)?
295 pfd[i].fd:ARES_SOCKET_BAD,
296 pfd[i].revents & (POLLWRNORM|POLLOUT)?
297 pfd[i].fd:ARES_SOCKET_BAD);
298 }
299 return nfds;
300}
301
302/*
303 * Curl_resolver_is_resolved() is called repeatedly to check if a previous
304 * name resolve request has completed. It should also make sure to time-out if
305 * the operation seems to take too long.
306 *
307 * Returns normal CURLcode errors.
308 */
309CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
310 struct Curl_dns_entry **dns)
311{
312 struct SessionHandle *data = conn->data;
313 struct ResolverResults *res = (struct ResolverResults *)
314 conn->async.os_specific;
315 CURLcode result = CURLE_OK;
316
317 *dns = NULL;
318
319 waitperform(conn, 0);
320
321 if(res && !res->num_pending) {
322 (void)Curl_addrinfo_callback(conn, res->last_status, res->temp_ai);
323 /* temp_ai ownership is moved to the connection, so we need not free-up
324 them */
325 res->temp_ai = NULL;
326 if(!conn->async.dns) {
327 failf(data, "Could not resolve: %s (%s)",
328 conn->async.hostname, ares_strerror(conn->async.status));
329 result = conn->bits.proxy?CURLE_COULDNT_RESOLVE_PROXY:
330 CURLE_COULDNT_RESOLVE_HOST;
331 }
332 else
333 *dns = conn->async.dns;
334
335 destroy_async_data(&conn->async);
336 }
337
338 return result;
339}
340
341/*
342 * Curl_resolver_wait_resolv()
343 *
344 * waits for a resolve to finish. This function should be avoided since using
345 * this risk getting the multi interface to "hang".
346 *
347 * If 'entry' is non-NULL, make it point to the resolved dns entry
348 *
349 * Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved, and
350 * CURLE_OPERATION_TIMEDOUT if a time-out occurred.
351 */
352CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
353 struct Curl_dns_entry **entry)
354{
355 CURLcode result = CURLE_OK;
356 struct SessionHandle *data = conn->data;
357 long timeout;
358 struct timeval now = Curl_tvnow();
359 struct Curl_dns_entry *temp_entry;
360
361 timeout = Curl_timeleft(data, &now, TRUE);
362 if(!timeout)
363 timeout = CURL_TIMEOUT_RESOLVE * 1000; /* default name resolve timeout */
364
365 /* Wait for the name resolve query to complete. */
366 for(;;) {
367 struct timeval *tvp, tv, store;
368 long timediff;
369 int itimeout;
370 int timeout_ms;
371
372 itimeout = (timeout > (long)INT_MAX) ? INT_MAX : (int)timeout;
373
374 store.tv_sec = itimeout/1000;
375 store.tv_usec = (itimeout%1000)*1000;
376
377 tvp = ares_timeout((ares_channel)data->state.resolver, &store, &tv);
378
379 /* use the timeout period ares returned to us above if less than one
380 second is left, otherwise just use 1000ms to make sure the progress
381 callback gets called frequent enough */
382 if(!tvp->tv_sec)
383 timeout_ms = (int)(tvp->tv_usec/1000);
384 else
385 timeout_ms = 1000;
386
387 waitperform(conn, timeout_ms);
388 Curl_resolver_is_resolved(conn, &temp_entry);
389
390 if(conn->async.done)
391 break;
392
393 if(Curl_pgrsUpdate(conn)) {
394 result = CURLE_ABORTED_BY_CALLBACK;
395 timeout = -1; /* trigger the cancel below */
396 }
397 else {
398 struct timeval now2 = Curl_tvnow();
399 timediff = Curl_tvdiff(now2, now); /* spent time */
400 timeout -= timediff?timediff:1; /* always deduct at least 1 */
401 now = now2; /* for next loop */
402 }
403
404 if(timeout < 0) {
405 /* our timeout, so we cancel the ares operation */
406 ares_cancel((ares_channel)data->state.resolver);
407 break;
408 }
409 }
410
411 /* Operation complete, if the lookup was successful we now have the entry
412 in the cache. */
413 if(entry)
414 *entry = conn->async.dns;
415
416 if(result)
417 /* close the connection, since we can't return failure here without
418 cleaning up this connection properly.
419 TODO: remove this action from here, it is not a name resolver decision.
420 */
421 connclose(conn, "c-ares resolve failed");
422
423 return result;
424}
425
426/* Connects results to the list */
427static void compound_results(struct ResolverResults *res,
428 Curl_addrinfo *ai)
429{
430 Curl_addrinfo *ai_tail;
431 if(!ai)
432 return;
433 ai_tail = ai;
434
435 while(ai_tail->ai_next)
436 ai_tail = ai_tail->ai_next;
437
438 /* Add the new results to the list of old results. */
439 ai_tail->ai_next = res->temp_ai;
440 res->temp_ai = ai;
441}
442
443/*
444 * ares_query_completed_cb() is the callback that ares will call when
445 * the host query initiated by ares_gethostbyname() from Curl_getaddrinfo(),
446 * when using ares, is completed either successfully or with failure.
447 */
448static void query_completed_cb(void *arg, /* (struct connectdata *) */
449 int status,
450#ifdef HAVE_CARES_CALLBACK_TIMEOUTS
451 int timeouts,
452#endif
453 struct hostent *hostent)
454{
455 struct connectdata *conn = (struct connectdata *)arg;
456 struct ResolverResults *res;
457
458#ifdef HAVE_CARES_CALLBACK_TIMEOUTS
459 (void)timeouts; /* ignored */
460#endif
461
462 if(ARES_EDESTRUCTION == status)
463 /* when this ares handle is getting destroyed, the 'arg' pointer may not
464 be valid so only defer it when we know the 'status' says its fine! */
465 return;
466
467 res = (struct ResolverResults *)conn->async.os_specific;
468 res->num_pending--;
469
470 if(CURL_ASYNC_SUCCESS == status) {
471 Curl_addrinfo *ai = Curl_he2ai(hostent, conn->async.port);
472 if(ai) {
473 compound_results(res, ai);
474 }
475 }
476 /* A successful result overwrites any previous error */
477 if(res->last_status != ARES_SUCCESS)
478 res->last_status = status;
479}
480
481/*
482 * Curl_resolver_getaddrinfo() - when using ares
483 *
484 * Returns name information about the given hostname and port number. If
485 * successful, the 'hostent' is returned and the forth argument will point to
486 * memory we need to free after use. That memory *MUST* be freed with
487 * Curl_freeaddrinfo(), nothing else.
488 */
489Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
490 const char *hostname,
491 int port,
492 int *waitp)
493{
494 char *bufp;
495 struct SessionHandle *data = conn->data;
496 struct in_addr in;
497 int family = PF_INET;
498#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
499 struct in6_addr in6;
500#endif /* CURLRES_IPV6 */
501
502 *waitp = 0; /* default to synchronous response */
503
504 /* First check if this is an IPv4 address string */
505 if(Curl_inet_pton(AF_INET, hostname, &in) > 0) {
506 /* This is a dotted IP address 123.123.123.123-style */
507 return Curl_ip2addr(AF_INET, &in, hostname, port);
508 }
509
510#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
511 /* Otherwise, check if this is an IPv6 address string */
512 if(Curl_inet_pton (AF_INET6, hostname, &in6) > 0)
513 /* This must be an IPv6 address literal. */
514 return Curl_ip2addr(AF_INET6, &in6, hostname, port);
515
516 switch(conn->ip_version) {
517 default:
518#if ARES_VERSION >= 0x010601
519 family = PF_UNSPEC; /* supported by c-ares since 1.6.1, so for older
520 c-ares versions this just falls through and defaults
521 to PF_INET */
522 break;
523#endif
524 case CURL_IPRESOLVE_V4:
525 family = PF_INET;
526 break;
527 case CURL_IPRESOLVE_V6:
528 family = PF_INET6;
529 break;
530 }
531#endif /* CURLRES_IPV6 */
532
533 bufp = strdup(hostname);
534 if(bufp) {
535 struct ResolverResults *res = NULL;
536 free(conn->async.hostname);
537 conn->async.hostname = bufp;
538 conn->async.port = port;
539 conn->async.done = FALSE; /* not done */
540 conn->async.status = 0; /* clear */
541 conn->async.dns = NULL; /* clear */
542 res = calloc(sizeof(struct ResolverResults), 1);
543 if(!res) {
544 free(conn->async.hostname);
545 conn->async.hostname = NULL;
546 return NULL;
547 }
548 conn->async.os_specific = res;
549
550 /* initial status - failed */
551 res->last_status = ARES_ENOTFOUND;
552#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
553 if(family == PF_UNSPEC) {
554 if(Curl_ipv6works()) {
555 res->num_pending = 2;
556
557 /* areschannel is already setup in the Curl_open() function */
558 ares_gethostbyname((ares_channel)data->state.resolver, hostname,
559 PF_INET, query_completed_cb, conn);
560 ares_gethostbyname((ares_channel)data->state.resolver, hostname,
561 PF_INET6, query_completed_cb, conn);
562 }
563 else {
564 res->num_pending = 1;
565
566 /* areschannel is already setup in the Curl_open() function */
567 ares_gethostbyname((ares_channel)data->state.resolver, hostname,
568 PF_INET, query_completed_cb, conn);
569 }
570 }
571 else
572#endif /* CURLRES_IPV6 */
573 {
574 res->num_pending = 1;
575
576 /* areschannel is already setup in the Curl_open() function */
577 ares_gethostbyname((ares_channel)data->state.resolver, hostname, family,
578 query_completed_cb, conn);
579 }
580
581 *waitp = 1; /* expect asynchronous response */
582 }
583 return NULL; /* no struct yet */
584}
585
586CURLcode Curl_set_dns_servers(struct SessionHandle *data,
587 char *servers)
588{
589 CURLcode result = CURLE_NOT_BUILT_IN;
590 int ares_result;
591
592 /* If server is NULL or empty, this would purge all DNS servers
593 * from ares library, which will cause any and all queries to fail.
594 * So, just return OK if none are configured and don't actually make
595 * any changes to c-ares. This lets c-ares use it's defaults, which
596 * it gets from the OS (for instance from /etc/resolv.conf on Linux).
597 */
598 if(!(servers && servers[0]))
599 return CURLE_OK;
600
601#if (ARES_VERSION >= 0x010704)
602 ares_result = ares_set_servers_csv(data->state.resolver, servers);
603 switch(ares_result) {
604 case ARES_SUCCESS:
605 result = CURLE_OK;
606 break;
607 case ARES_ENOMEM:
608 result = CURLE_OUT_OF_MEMORY;
609 break;
610 case ARES_ENOTINITIALIZED:
611 case ARES_ENODATA:
612 case ARES_EBADSTR:
613 default:
614 result = CURLE_BAD_FUNCTION_ARGUMENT;
615 break;
616 }
617#else /* too old c-ares version! */
618 (void)data;
619 (void)(ares_result);
620#endif
621 return result;
622}
623
624CURLcode Curl_set_dns_interface(struct SessionHandle *data,
625 const char *interf)
626{
627#if (ARES_VERSION >= 0x010704)
628 if(!interf)
629 interf = "";
630
631 ares_set_local_dev((ares_channel)data->state.resolver, interf);
632
633 return CURLE_OK;
634#else /* c-ares version too old! */
635 (void)data;
636 (void)interf;
637 return CURLE_NOT_BUILT_IN;
638#endif
639}
640
641CURLcode Curl_set_dns_local_ip4(struct SessionHandle *data,
642 const char *local_ip4)
643{
644#if (ARES_VERSION >= 0x010704)
645 struct in_addr a4;
646
647 if((!local_ip4) || (local_ip4[0] == 0)) {
648 a4.s_addr = 0; /* disabled: do not bind to a specific address */
649 }
650 else {
651 if(Curl_inet_pton(AF_INET, local_ip4, &a4) != 1) {
652 return CURLE_BAD_FUNCTION_ARGUMENT;
653 }
654 }
655
656 ares_set_local_ip4((ares_channel)data->state.resolver, ntohl(a4.s_addr));
657
658 return CURLE_OK;
659#else /* c-ares version too old! */
660 (void)data;
661 (void)local_ip4;
662 return CURLE_NOT_BUILT_IN;
663#endif
664}
665
666CURLcode Curl_set_dns_local_ip6(struct SessionHandle *data,
667 const char *local_ip6)
668{
669#if (ARES_VERSION >= 0x010704) && defined(ENABLE_IPV6)
670 unsigned char a6[INET6_ADDRSTRLEN];
671
672 if((!local_ip6) || (local_ip6[0] == 0)) {
673 /* disabled: do not bind to a specific address */
674 memset(a6, 0, sizeof(a6));
675 }
676 else {
677 if(Curl_inet_pton(AF_INET6, local_ip6, a6) != 1) {
678 return CURLE_BAD_FUNCTION_ARGUMENT;
679 }
680 }
681
682 ares_set_local_ip6((ares_channel)data->state.resolver, a6);
683
684 return CURLE_OK;
685#else /* c-ares version too old! */
686 (void)data;
687 (void)local_ip6;
688 return CURLE_NOT_BUILT_IN;
689#endif
690}
691#endif /* CURLRES_ARES */
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