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Diffstat (limited to 'src/util/dnsstub.c')
-rw-r--r-- | src/util/dnsstub.c | 747 |
1 files changed, 747 insertions, 0 deletions
diff --git a/src/util/dnsstub.c b/src/util/dnsstub.c new file mode 100644 index 000000000..5b84e6e63 --- /dev/null +++ b/src/util/dnsstub.c | |||
@@ -0,0 +1,747 @@ | |||
1 | /* | ||
2 | This file is part of GNUnet. | ||
3 | Copyright (C) 2012, 2018 GNUnet e.V. | ||
4 | |||
5 | GNUnet is free software: you can redistribute it and/or modify it | ||
6 | under the terms of the GNU Affero General Public License as published | ||
7 | by the Free Software Foundation, either version 3 of the License, | ||
8 | or (at your option) any later version. | ||
9 | |||
10 | GNUnet is distributed in the hope that it will be useful, but | ||
11 | WITHOUT ANY WARRANTY; without even the implied warranty of | ||
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
13 | Affero General Public License for more details. | ||
14 | |||
15 | You should have received a copy of the GNU Affero General Public License | ||
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. | ||
17 | */ | ||
18 | /** | ||
19 | * @file dns/dnsstub.c | ||
20 | * @brief DNS stub resolver which sends DNS requests to an actual resolver | ||
21 | * @author Christian Grothoff | ||
22 | */ | ||
23 | #include "platform.h" | ||
24 | #include "gnunet_util_lib.h" | ||
25 | |||
26 | /** | ||
27 | * Timeout for retrying DNS queries. | ||
28 | */ | ||
29 | #define DNS_RETRANSMIT_DELAY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 250) | ||
30 | |||
31 | |||
32 | /** | ||
33 | * DNS Server used for resolution. | ||
34 | */ | ||
35 | struct DnsServer; | ||
36 | |||
37 | |||
38 | /** | ||
39 | * UDP socket we are using for sending DNS requests to the Internet. | ||
40 | */ | ||
41 | struct GNUNET_DNSSTUB_RequestSocket | ||
42 | { | ||
43 | |||
44 | /** | ||
45 | * UDP socket we use for this request for IPv4 | ||
46 | */ | ||
47 | struct GNUNET_NETWORK_Handle *dnsout4; | ||
48 | |||
49 | /** | ||
50 | * UDP socket we use for this request for IPv6 | ||
51 | */ | ||
52 | struct GNUNET_NETWORK_Handle *dnsout6; | ||
53 | |||
54 | /** | ||
55 | * Function to call with result. | ||
56 | */ | ||
57 | GNUNET_DNSSTUB_ResultCallback rc; | ||
58 | |||
59 | /** | ||
60 | * Closure for @e rc. | ||
61 | */ | ||
62 | void *rc_cls; | ||
63 | |||
64 | /** | ||
65 | * Task for reading from dnsout4 and dnsout6. | ||
66 | */ | ||
67 | struct GNUNET_SCHEDULER_Task *read_task; | ||
68 | |||
69 | /** | ||
70 | * Task for retrying transmission of the query. | ||
71 | */ | ||
72 | struct GNUNET_SCHEDULER_Task *retry_task; | ||
73 | |||
74 | /** | ||
75 | * Next address we sent the DNS request to. | ||
76 | */ | ||
77 | struct DnsServer *ds_pos; | ||
78 | |||
79 | /** | ||
80 | * Context this request executes in. | ||
81 | */ | ||
82 | struct GNUNET_DNSSTUB_Context *ctx; | ||
83 | |||
84 | /** | ||
85 | * Query we sent to @e addr. | ||
86 | */ | ||
87 | void *request; | ||
88 | |||
89 | /** | ||
90 | * Number of bytes in @a request. | ||
91 | */ | ||
92 | size_t request_len; | ||
93 | |||
94 | }; | ||
95 | |||
96 | |||
97 | /** | ||
98 | * DNS Server used for resolution. | ||
99 | */ | ||
100 | struct DnsServer | ||
101 | { | ||
102 | |||
103 | /** | ||
104 | * Kept in a DLL. | ||
105 | */ | ||
106 | struct DnsServer *next; | ||
107 | |||
108 | /** | ||
109 | * Kept in a DLL. | ||
110 | */ | ||
111 | struct DnsServer *prev; | ||
112 | |||
113 | /** | ||
114 | * IP address of the DNS resolver. | ||
115 | */ | ||
116 | struct sockaddr_storage ss; | ||
117 | }; | ||
118 | |||
119 | |||
120 | /** | ||
121 | * Handle to the stub resolver. | ||
122 | */ | ||
123 | struct GNUNET_DNSSTUB_Context | ||
124 | { | ||
125 | |||
126 | /** | ||
127 | * Array of all open sockets for DNS requests. | ||
128 | */ | ||
129 | struct GNUNET_DNSSTUB_RequestSocket *sockets; | ||
130 | |||
131 | /** | ||
132 | * DLL of DNS resolvers we use. | ||
133 | */ | ||
134 | struct DnsServer *dns_head; | ||
135 | |||
136 | /** | ||
137 | * DLL of DNS resolvers we use. | ||
138 | */ | ||
139 | struct DnsServer *dns_tail; | ||
140 | |||
141 | /** | ||
142 | * How frequently do we retry requests? | ||
143 | */ | ||
144 | struct GNUNET_TIME_Relative retry_freq; | ||
145 | |||
146 | /** | ||
147 | * Length of @e sockets array. | ||
148 | */ | ||
149 | unsigned int num_sockets; | ||
150 | |||
151 | }; | ||
152 | |||
153 | |||
154 | /** | ||
155 | * We're done with a `struct GNUNET_DNSSTUB_RequestSocket`, close it for now. | ||
156 | * | ||
157 | * @param rs request socket to clean up | ||
158 | */ | ||
159 | static void | ||
160 | cleanup_rs (struct GNUNET_DNSSTUB_RequestSocket *rs) | ||
161 | { | ||
162 | if (NULL != rs->dnsout4) | ||
163 | { | ||
164 | GNUNET_NETWORK_socket_close (rs->dnsout4); | ||
165 | rs->dnsout4 = NULL; | ||
166 | } | ||
167 | if (NULL != rs->dnsout6) | ||
168 | { | ||
169 | GNUNET_NETWORK_socket_close (rs->dnsout6); | ||
170 | rs->dnsout6 = NULL; | ||
171 | } | ||
172 | if (NULL != rs->read_task) | ||
173 | { | ||
174 | GNUNET_SCHEDULER_cancel (rs->read_task); | ||
175 | rs->read_task = NULL; | ||
176 | } | ||
177 | if (NULL != rs->retry_task) | ||
178 | { | ||
179 | GNUNET_SCHEDULER_cancel (rs->retry_task); | ||
180 | rs->retry_task = NULL; | ||
181 | } | ||
182 | if (NULL != rs->request) | ||
183 | { | ||
184 | GNUNET_free (rs->request); | ||
185 | rs->request = NULL; | ||
186 | } | ||
187 | } | ||
188 | |||
189 | |||
190 | /** | ||
191 | * Open source port for sending DNS requests | ||
192 | * | ||
193 | * @param af AF_INET or AF_INET6 | ||
194 | * @return #GNUNET_OK on success | ||
195 | */ | ||
196 | static struct GNUNET_NETWORK_Handle * | ||
197 | open_socket (int af) | ||
198 | { | ||
199 | struct sockaddr_in a4; | ||
200 | struct sockaddr_in6 a6; | ||
201 | struct sockaddr *sa; | ||
202 | socklen_t alen; | ||
203 | struct GNUNET_NETWORK_Handle *ret; | ||
204 | |||
205 | ret = GNUNET_NETWORK_socket_create (af, SOCK_DGRAM, 0); | ||
206 | if (NULL == ret) | ||
207 | return NULL; | ||
208 | switch (af) | ||
209 | { | ||
210 | case AF_INET: | ||
211 | memset (&a4, 0, alen = sizeof (struct sockaddr_in)); | ||
212 | sa = (struct sockaddr *) &a4; | ||
213 | break; | ||
214 | case AF_INET6: | ||
215 | memset (&a6, 0, alen = sizeof (struct sockaddr_in6)); | ||
216 | sa = (struct sockaddr *) &a6; | ||
217 | break; | ||
218 | default: | ||
219 | GNUNET_break (0); | ||
220 | GNUNET_NETWORK_socket_close (ret); | ||
221 | return NULL; | ||
222 | } | ||
223 | sa->sa_family = af; | ||
224 | if (GNUNET_OK != GNUNET_NETWORK_socket_bind (ret, | ||
225 | sa, | ||
226 | alen)) | ||
227 | { | ||
228 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
229 | _("Could not bind to any port: %s\n"), | ||
230 | STRERROR (errno)); | ||
231 | GNUNET_NETWORK_socket_close (ret); | ||
232 | return NULL; | ||
233 | } | ||
234 | return ret; | ||
235 | } | ||
236 | |||
237 | |||
238 | /** | ||
239 | * Get a socket of the specified address family to send out a | ||
240 | * UDP DNS request to the Internet. | ||
241 | * | ||
242 | * @param ctx the DNSSTUB context | ||
243 | * @return NULL on error | ||
244 | */ | ||
245 | static struct GNUNET_DNSSTUB_RequestSocket * | ||
246 | get_request_socket (struct GNUNET_DNSSTUB_Context *ctx) | ||
247 | { | ||
248 | struct GNUNET_DNSSTUB_RequestSocket *rs; | ||
249 | |||
250 | for (unsigned int i=0;i<256;i++) | ||
251 | { | ||
252 | rs = &ctx->sockets[GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, | ||
253 | ctx->num_sockets)]; | ||
254 | if (NULL == rs->rc) | ||
255 | break; | ||
256 | } | ||
257 | if (NULL != rs->rc) | ||
258 | { | ||
259 | /* signal "failure" */ | ||
260 | rs->rc (rs->rc_cls, | ||
261 | NULL, | ||
262 | 0); | ||
263 | rs->rc = NULL; | ||
264 | } | ||
265 | if (NULL != rs->read_task) | ||
266 | { | ||
267 | GNUNET_SCHEDULER_cancel (rs->read_task); | ||
268 | rs->read_task = NULL; | ||
269 | } | ||
270 | if (NULL != rs->retry_task) | ||
271 | { | ||
272 | GNUNET_SCHEDULER_cancel (rs->retry_task); | ||
273 | rs->retry_task = NULL; | ||
274 | } | ||
275 | if (NULL != rs->request) | ||
276 | { | ||
277 | GNUNET_free (rs->request); | ||
278 | rs->request = NULL; | ||
279 | } | ||
280 | rs->ctx = ctx; | ||
281 | return rs; | ||
282 | } | ||
283 | |||
284 | |||
285 | /** | ||
286 | * Actually do the reading of a DNS packet from our UDP socket and see | ||
287 | * if we have a valid, matching, pending request. | ||
288 | * | ||
289 | * @param rs request socket with callback details | ||
290 | * @param dnsout socket to read from | ||
291 | * @return #GNUNET_OK on success, #GNUNET_NO on drop, #GNUNET_SYSERR on IO-errors (closed socket) | ||
292 | */ | ||
293 | static int | ||
294 | do_dns_read (struct GNUNET_DNSSTUB_RequestSocket *rs, | ||
295 | struct GNUNET_NETWORK_Handle *dnsout) | ||
296 | { | ||
297 | struct GNUNET_DNSSTUB_Context *ctx = rs->ctx; | ||
298 | ssize_t r; | ||
299 | int len; | ||
300 | |||
301 | #ifndef MINGW | ||
302 | if (0 != ioctl (GNUNET_NETWORK_get_fd (dnsout), | ||
303 | FIONREAD, | ||
304 | &len)) | ||
305 | { | ||
306 | /* conservative choice: */ | ||
307 | len = UINT16_MAX; | ||
308 | } | ||
309 | #else | ||
310 | /* port the code above? */ | ||
311 | len = UINT16_MAX; | ||
312 | #endif | ||
313 | GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, | ||
314 | "Receiving %d byte DNS reply\n", | ||
315 | len); | ||
316 | { | ||
317 | unsigned char buf[len] GNUNET_ALIGN; | ||
318 | int found; | ||
319 | struct sockaddr_storage addr; | ||
320 | socklen_t addrlen; | ||
321 | struct GNUNET_TUN_DnsHeader *dns; | ||
322 | |||
323 | addrlen = sizeof (addr); | ||
324 | memset (&addr, | ||
325 | 0, | ||
326 | sizeof (addr)); | ||
327 | r = GNUNET_NETWORK_socket_recvfrom (dnsout, | ||
328 | buf, | ||
329 | sizeof (buf), | ||
330 | (struct sockaddr*) &addr, | ||
331 | &addrlen); | ||
332 | if (-1 == r) | ||
333 | { | ||
334 | GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, | ||
335 | "recvfrom"); | ||
336 | GNUNET_NETWORK_socket_close (dnsout); | ||
337 | return GNUNET_SYSERR; | ||
338 | } | ||
339 | found = GNUNET_NO; | ||
340 | for (struct DnsServer *ds = ctx->dns_head; NULL != ds; ds = ds->next) | ||
341 | { | ||
342 | if (0 == memcmp (&addr, | ||
343 | &ds->ss, | ||
344 | GNUNET_MIN (sizeof (struct sockaddr_storage), | ||
345 | addrlen))) | ||
346 | { | ||
347 | found = GNUNET_YES; | ||
348 | break; | ||
349 | } | ||
350 | } | ||
351 | if (GNUNET_NO == found) | ||
352 | { | ||
353 | GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, | ||
354 | "Received DNS response from server we never asked (ignored)"); | ||
355 | return GNUNET_NO; | ||
356 | } | ||
357 | if (sizeof (struct GNUNET_TUN_DnsHeader) > (size_t) r) | ||
358 | { | ||
359 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
360 | _("Received DNS response that is too small (%u bytes)"), | ||
361 | (unsigned int) r); | ||
362 | return GNUNET_NO; | ||
363 | } | ||
364 | dns = (struct GNUNET_TUN_DnsHeader *) buf; | ||
365 | if (NULL == rs->rc) | ||
366 | { | ||
367 | GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, | ||
368 | "Request timeout or cancelled; ignoring reply\n"); | ||
369 | return GNUNET_NO; | ||
370 | } | ||
371 | rs->rc (rs->rc_cls, | ||
372 | dns, | ||
373 | r); | ||
374 | } | ||
375 | return GNUNET_OK; | ||
376 | } | ||
377 | |||
378 | |||
379 | /** | ||
380 | * Read a DNS response from the (unhindered) UDP-Socket | ||
381 | * | ||
382 | * @param cls socket to read from | ||
383 | */ | ||
384 | static void | ||
385 | read_response (void *cls); | ||
386 | |||
387 | |||
388 | /** | ||
389 | * Schedule #read_response() task for @a rs. | ||
390 | * | ||
391 | * @param rs request to schedule read operation for | ||
392 | */ | ||
393 | static void | ||
394 | schedule_read (struct GNUNET_DNSSTUB_RequestSocket *rs) | ||
395 | { | ||
396 | struct GNUNET_NETWORK_FDSet *rset; | ||
397 | |||
398 | if (NULL != rs->read_task) | ||
399 | GNUNET_SCHEDULER_cancel (rs->read_task); | ||
400 | rset = GNUNET_NETWORK_fdset_create (); | ||
401 | if (NULL != rs->dnsout4) | ||
402 | GNUNET_NETWORK_fdset_set (rset, | ||
403 | rs->dnsout4); | ||
404 | if (NULL != rs->dnsout6) | ||
405 | GNUNET_NETWORK_fdset_set (rset, | ||
406 | rs->dnsout6); | ||
407 | rs->read_task = GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT, | ||
408 | GNUNET_TIME_UNIT_FOREVER_REL, | ||
409 | rset, | ||
410 | NULL, | ||
411 | &read_response, | ||
412 | rs); | ||
413 | GNUNET_NETWORK_fdset_destroy (rset); | ||
414 | } | ||
415 | |||
416 | |||
417 | /** | ||
418 | * Read a DNS response from the (unhindered) UDP-Socket | ||
419 | * | ||
420 | * @param cls `struct GNUNET_DNSSTUB_RequestSocket` to read from | ||
421 | */ | ||
422 | static void | ||
423 | read_response (void *cls) | ||
424 | { | ||
425 | struct GNUNET_DNSSTUB_RequestSocket *rs = cls; | ||
426 | const struct GNUNET_SCHEDULER_TaskContext *tc; | ||
427 | |||
428 | rs->read_task = NULL; | ||
429 | tc = GNUNET_SCHEDULER_get_task_context (); | ||
430 | /* read and process ready sockets */ | ||
431 | if ( (NULL != rs->dnsout4) && | ||
432 | (GNUNET_NETWORK_fdset_isset (tc->read_ready, | ||
433 | rs->dnsout4)) && | ||
434 | (GNUNET_SYSERR == | ||
435 | do_dns_read (rs, | ||
436 | rs->dnsout4)) ) | ||
437 | rs->dnsout4 = NULL; | ||
438 | if ( (NULL != rs->dnsout6) && | ||
439 | (GNUNET_NETWORK_fdset_isset (tc->read_ready, | ||
440 | rs->dnsout6)) && | ||
441 | (GNUNET_SYSERR == | ||
442 | do_dns_read (rs, | ||
443 | rs->dnsout6)) ) | ||
444 | rs->dnsout6 = NULL; | ||
445 | /* re-schedule read task */ | ||
446 | schedule_read (rs); | ||
447 | } | ||
448 | |||
449 | |||
450 | /** | ||
451 | * Task to (re)transmit the DNS query, possibly repeatedly until | ||
452 | * we succeed. | ||
453 | * | ||
454 | * @param cls our `struct GNUNET_DNSSTUB_RequestSocket *` | ||
455 | */ | ||
456 | static void | ||
457 | transmit_query (void *cls) | ||
458 | { | ||
459 | struct GNUNET_DNSSTUB_RequestSocket *rs = cls; | ||
460 | struct GNUNET_DNSSTUB_Context *ctx = rs->ctx; | ||
461 | const struct sockaddr *sa; | ||
462 | socklen_t salen; | ||
463 | struct DnsServer *ds; | ||
464 | struct GNUNET_NETWORK_Handle *dnsout; | ||
465 | |||
466 | rs->retry_task = GNUNET_SCHEDULER_add_delayed (ctx->retry_freq, | ||
467 | &transmit_query, | ||
468 | rs); | ||
469 | ds = rs->ds_pos; | ||
470 | rs->ds_pos = ds->next; | ||
471 | if (NULL == rs->ds_pos) | ||
472 | rs->ds_pos = ctx->dns_head; | ||
473 | GNUNET_assert (NULL != ds); | ||
474 | dnsout = NULL; | ||
475 | switch (ds->ss.ss_family) | ||
476 | { | ||
477 | case AF_INET: | ||
478 | if (NULL == rs->dnsout4) | ||
479 | rs->dnsout4 = open_socket (AF_INET); | ||
480 | dnsout = rs->dnsout4; | ||
481 | sa = (const struct sockaddr *) &ds->ss; | ||
482 | salen = sizeof (struct sockaddr_in); | ||
483 | break; | ||
484 | case AF_INET6: | ||
485 | if (NULL == rs->dnsout6) | ||
486 | rs->dnsout6 = open_socket (AF_INET6); | ||
487 | dnsout = rs->dnsout6; | ||
488 | sa = (const struct sockaddr *) &ds->ss; | ||
489 | salen = sizeof (struct sockaddr_in6); | ||
490 | break; | ||
491 | default: | ||
492 | return; | ||
493 | } | ||
494 | if (NULL == dnsout) | ||
495 | { | ||
496 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
497 | "Unable to use configure DNS server, skipping\n"); | ||
498 | return; | ||
499 | } | ||
500 | if (GNUNET_SYSERR == | ||
501 | GNUNET_NETWORK_socket_sendto (dnsout, | ||
502 | rs->request, | ||
503 | rs->request_len, | ||
504 | sa, | ||
505 | salen)) | ||
506 | GNUNET_log (GNUNET_ERROR_TYPE_WARNING, | ||
507 | _("Failed to send DNS request to %s: %s\n"), | ||
508 | GNUNET_a2s (sa, | ||
509 | salen), | ||
510 | STRERROR (errno)); | ||
511 | else | ||
512 | GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, | ||
513 | _("Sent DNS request to %s\n"), | ||
514 | GNUNET_a2s (sa, | ||
515 | salen)); | ||
516 | schedule_read (rs); | ||
517 | } | ||
518 | |||
519 | |||
520 | /** | ||
521 | * Perform DNS resolution using our default IP from init. | ||
522 | * | ||
523 | * @param ctx stub resolver to use | ||
524 | * @param request DNS request to transmit | ||
525 | * @param request_len number of bytes in msg | ||
526 | * @param rc function to call with result | ||
527 | * @param rc_cls closure for 'rc' | ||
528 | * @return socket used for the request, NULL on error | ||
529 | */ | ||
530 | struct GNUNET_DNSSTUB_RequestSocket * | ||
531 | GNUNET_DNSSTUB_resolve (struct GNUNET_DNSSTUB_Context *ctx, | ||
532 | const void *request, | ||
533 | size_t request_len, | ||
534 | GNUNET_DNSSTUB_ResultCallback rc, | ||
535 | void *rc_cls) | ||
536 | { | ||
537 | struct GNUNET_DNSSTUB_RequestSocket *rs; | ||
538 | |||
539 | if (NULL == ctx->dns_head) | ||
540 | { | ||
541 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
542 | "No DNS server configured for resolution\n"); | ||
543 | return NULL; | ||
544 | } | ||
545 | if (NULL == (rs = get_request_socket (ctx))) | ||
546 | { | ||
547 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
548 | "No request socket available for DNS resolution\n"); | ||
549 | return NULL; | ||
550 | } | ||
551 | rs->ds_pos = ctx->dns_head; | ||
552 | rs->rc = rc; | ||
553 | rs->rc_cls = rc_cls; | ||
554 | rs->request = GNUNET_memdup (request, | ||
555 | request_len); | ||
556 | rs->request_len = request_len; | ||
557 | rs->retry_task = GNUNET_SCHEDULER_add_now (&transmit_query, | ||
558 | rs); | ||
559 | return rs; | ||
560 | } | ||
561 | |||
562 | |||
563 | /** | ||
564 | * Cancel DNS resolution. | ||
565 | * | ||
566 | * @param rs resolution to cancel | ||
567 | */ | ||
568 | void | ||
569 | GNUNET_DNSSTUB_resolve_cancel (struct GNUNET_DNSSTUB_RequestSocket *rs) | ||
570 | { | ||
571 | rs->rc = NULL; | ||
572 | if (NULL != rs->retry_task) | ||
573 | { | ||
574 | GNUNET_SCHEDULER_cancel (rs->retry_task); | ||
575 | rs->retry_task = NULL; | ||
576 | } | ||
577 | if (NULL != rs->read_task) | ||
578 | { | ||
579 | GNUNET_SCHEDULER_cancel (rs->read_task); | ||
580 | rs->read_task = NULL; | ||
581 | } | ||
582 | } | ||
583 | |||
584 | |||
585 | /** | ||
586 | * Start a DNS stub resolver. | ||
587 | * | ||
588 | * @param num_sockets how many sockets should we open | ||
589 | * in parallel for DNS queries for this stub? | ||
590 | * @return NULL on error | ||
591 | */ | ||
592 | struct GNUNET_DNSSTUB_Context * | ||
593 | GNUNET_DNSSTUB_start (unsigned int num_sockets) | ||
594 | { | ||
595 | struct GNUNET_DNSSTUB_Context *ctx; | ||
596 | |||
597 | if (0 == num_sockets) | ||
598 | { | ||
599 | GNUNET_break (0); | ||
600 | return NULL; | ||
601 | } | ||
602 | ctx = GNUNET_new (struct GNUNET_DNSSTUB_Context); | ||
603 | ctx->num_sockets = num_sockets; | ||
604 | ctx->sockets = GNUNET_new_array (num_sockets, | ||
605 | struct GNUNET_DNSSTUB_RequestSocket); | ||
606 | ctx->retry_freq = DNS_RETRANSMIT_DELAY; | ||
607 | return ctx; | ||
608 | } | ||
609 | |||
610 | |||
611 | /** | ||
612 | * Add nameserver for use by the DNSSTUB. We will use | ||
613 | * all provided nameservers for resolution (round-robin). | ||
614 | * | ||
615 | * @param ctx resolver context to modify | ||
616 | * @param dns_ip target IP address to use (as string) | ||
617 | * @return #GNUNET_OK on success | ||
618 | */ | ||
619 | int | ||
620 | GNUNET_DNSSTUB_add_dns_ip (struct GNUNET_DNSSTUB_Context *ctx, | ||
621 | const char *dns_ip) | ||
622 | { | ||
623 | struct DnsServer *ds; | ||
624 | struct in_addr i4; | ||
625 | struct in6_addr i6; | ||
626 | |||
627 | ds = GNUNET_new (struct DnsServer); | ||
628 | if (1 == inet_pton (AF_INET, | ||
629 | dns_ip, | ||
630 | &i4)) | ||
631 | { | ||
632 | struct sockaddr_in *s4 = (struct sockaddr_in *) &ds->ss; | ||
633 | |||
634 | s4->sin_family = AF_INET; | ||
635 | s4->sin_port = htons (53); | ||
636 | s4->sin_addr = i4; | ||
637 | #if HAVE_SOCKADDR_IN_SIN_LEN | ||
638 | s4->sin_len = (u_char) sizeof (struct sockaddr_in); | ||
639 | #endif | ||
640 | } | ||
641 | else if (1 == inet_pton (AF_INET6, | ||
642 | dns_ip, | ||
643 | &i6)) | ||
644 | { | ||
645 | struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) &ds->ss; | ||
646 | |||
647 | s6->sin6_family = AF_INET6; | ||
648 | s6->sin6_port = htons (53); | ||
649 | s6->sin6_addr = i6; | ||
650 | #if HAVE_SOCKADDR_IN_SIN_LEN | ||
651 | s6->sin6_len = (u_char) sizeof (struct sockaddr_in6); | ||
652 | #endif | ||
653 | } | ||
654 | else | ||
655 | { | ||
656 | GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, | ||
657 | "Malformed IP address `%s' for DNS server\n", | ||
658 | dns_ip); | ||
659 | GNUNET_free (ds); | ||
660 | return GNUNET_SYSERR; | ||
661 | } | ||
662 | GNUNET_CONTAINER_DLL_insert (ctx->dns_head, | ||
663 | ctx->dns_tail, | ||
664 | ds); | ||
665 | return GNUNET_OK; | ||
666 | } | ||
667 | |||
668 | |||
669 | /** | ||
670 | * Add nameserver for use by the DNSSTUB. We will use | ||
671 | * all provided nameservers for resolution (round-robin). | ||
672 | * | ||
673 | * @param ctx resolver context to modify | ||
674 | * @param sa socket address of DNS resolver to use | ||
675 | * @return #GNUNET_OK on success | ||
676 | */ | ||
677 | int | ||
678 | GNUNET_DNSSTUB_add_dns_sa (struct GNUNET_DNSSTUB_Context *ctx, | ||
679 | const struct sockaddr *sa) | ||
680 | { | ||
681 | struct DnsServer *ds; | ||
682 | |||
683 | ds = GNUNET_new (struct DnsServer); | ||
684 | switch (sa->sa_family) | ||
685 | { | ||
686 | case AF_INET: | ||
687 | GNUNET_memcpy (&ds->ss, | ||
688 | sa, | ||
689 | sizeof (struct sockaddr_in)); | ||
690 | break; | ||
691 | case AF_INET6: | ||
692 | GNUNET_memcpy (&ds->ss, | ||
693 | sa, | ||
694 | sizeof (struct sockaddr_in6)); | ||
695 | break; | ||
696 | default: | ||
697 | GNUNET_break (0); | ||
698 | GNUNET_free (ds); | ||
699 | return GNUNET_SYSERR; | ||
700 | } | ||
701 | GNUNET_CONTAINER_DLL_insert (ctx->dns_head, | ||
702 | ctx->dns_tail, | ||
703 | ds); | ||
704 | return GNUNET_OK; | ||
705 | } | ||
706 | |||
707 | |||
708 | /** | ||
709 | * How long should we try requests before timing out? | ||
710 | * Only effective for requests issued after this call. | ||
711 | * | ||
712 | * @param ctx resolver context to modify | ||
713 | * @param retry_freq how long to wait between retries | ||
714 | */ | ||
715 | void | ||
716 | GNUNET_DNSSTUB_set_retry (struct GNUNET_DNSSTUB_Context *ctx, | ||
717 | struct GNUNET_TIME_Relative retry_freq) | ||
718 | { | ||
719 | ctx->retry_freq = retry_freq; | ||
720 | } | ||
721 | |||
722 | |||
723 | /** | ||
724 | * Cleanup DNSSTUB resolver. | ||
725 | * | ||
726 | * @param ctx stub resolver to clean up | ||
727 | */ | ||
728 | void | ||
729 | GNUNET_DNSSTUB_stop (struct GNUNET_DNSSTUB_Context *ctx) | ||
730 | { | ||
731 | struct DnsServer *ds; | ||
732 | |||
733 | while (NULL != (ds = ctx->dns_head)) | ||
734 | { | ||
735 | GNUNET_CONTAINER_DLL_remove (ctx->dns_head, | ||
736 | ctx->dns_tail, | ||
737 | ds); | ||
738 | GNUNET_free (ds); | ||
739 | } | ||
740 | for (unsigned int i=0;i<ctx->num_sockets;i++) | ||
741 | cleanup_rs (&ctx->sockets[i]); | ||
742 | GNUNET_free (ctx->sockets); | ||
743 | GNUNET_free (ctx); | ||
744 | } | ||
745 | |||
746 | |||
747 | /* end of dnsstub.c */ | ||