diff options
Diffstat (limited to 'src/util/dnsstub.c')
-rw-r--r-- | src/util/dnsstub.c | 732 |
1 files changed, 0 insertions, 732 deletions
diff --git a/src/util/dnsstub.c b/src/util/dnsstub.c deleted file mode 100644 index c2f2a441f..000000000 --- a/src/util/dnsstub.c +++ /dev/null | |||
@@ -1,732 +0,0 @@ | |||
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 | SPDX-License-Identifier: AGPL3.0-or-later | ||
19 | */ | ||
20 | /** | ||
21 | * @file dns/dnsstub.c | ||
22 | * @brief DNS stub resolver which sends DNS requests to an actual resolver | ||
23 | * @author Christian Grothoff | ||
24 | */ | ||
25 | #include "platform.h" | ||
26 | #include "gnunet_util_lib.h" | ||
27 | |||
28 | /** | ||
29 | * Timeout for retrying DNS queries. | ||
30 | */ | ||
31 | #define DNS_RETRANSMIT_DELAY \ | ||
32 | GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 250) | ||
33 | |||
34 | |||
35 | /** | ||
36 | * DNS Server used for resolution. | ||
37 | */ | ||
38 | struct DnsServer; | ||
39 | |||
40 | |||
41 | /** | ||
42 | * UDP socket we are using for sending DNS requests to the Internet. | ||
43 | */ | ||
44 | struct GNUNET_DNSSTUB_RequestSocket | ||
45 | { | ||
46 | /** | ||
47 | * UDP socket we use for this request for IPv4 | ||
48 | */ | ||
49 | struct GNUNET_NETWORK_Handle *dnsout4; | ||
50 | |||
51 | /** | ||
52 | * UDP socket we use for this request for IPv6 | ||
53 | */ | ||
54 | struct GNUNET_NETWORK_Handle *dnsout6; | ||
55 | |||
56 | /** | ||
57 | * Function to call with result. | ||
58 | */ | ||
59 | GNUNET_DNSSTUB_ResultCallback rc; | ||
60 | |||
61 | /** | ||
62 | * Closure for @e rc. | ||
63 | */ | ||
64 | void *rc_cls; | ||
65 | |||
66 | /** | ||
67 | * Task for reading from dnsout4 and dnsout6. | ||
68 | */ | ||
69 | struct GNUNET_SCHEDULER_Task *read_task; | ||
70 | |||
71 | /** | ||
72 | * Task for retrying transmission of the query. | ||
73 | */ | ||
74 | struct GNUNET_SCHEDULER_Task *retry_task; | ||
75 | |||
76 | /** | ||
77 | * Next address we sent the DNS request to. | ||
78 | */ | ||
79 | struct DnsServer *ds_pos; | ||
80 | |||
81 | /** | ||
82 | * Context this request executes in. | ||
83 | */ | ||
84 | struct GNUNET_DNSSTUB_Context *ctx; | ||
85 | |||
86 | /** | ||
87 | * Query we sent to @e addr. | ||
88 | */ | ||
89 | void *request; | ||
90 | |||
91 | /** | ||
92 | * Number of bytes in @a request. | ||
93 | */ | ||
94 | size_t request_len; | ||
95 | }; | ||
96 | |||
97 | |||
98 | /** | ||
99 | * DNS Server used for resolution. | ||
100 | */ | ||
101 | struct DnsServer | ||
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 | * Array of all open sockets for DNS requests. | ||
127 | */ | ||
128 | struct GNUNET_DNSSTUB_RequestSocket *sockets; | ||
129 | |||
130 | /** | ||
131 | * DLL of DNS resolvers we use. | ||
132 | */ | ||
133 | struct DnsServer *dns_head; | ||
134 | |||
135 | /** | ||
136 | * DLL of DNS resolvers we use. | ||
137 | */ | ||
138 | struct DnsServer *dns_tail; | ||
139 | |||
140 | /** | ||
141 | * How frequently do we retry requests? | ||
142 | */ | ||
143 | struct GNUNET_TIME_Relative retry_freq; | ||
144 | |||
145 | /** | ||
146 | * Length of @e sockets array. | ||
147 | */ | ||
148 | unsigned int num_sockets; | ||
149 | }; | ||
150 | |||
151 | |||
152 | /** | ||
153 | * We're done with a `struct GNUNET_DNSSTUB_RequestSocket`, close it for now. | ||
154 | * | ||
155 | * @param rs request socket to clean up | ||
156 | */ | ||
157 | static void | ||
158 | cleanup_rs (struct GNUNET_DNSSTUB_RequestSocket *rs) | ||
159 | { | ||
160 | if (NULL != rs->dnsout4) | ||
161 | { | ||
162 | GNUNET_NETWORK_socket_close (rs->dnsout4); | ||
163 | rs->dnsout4 = NULL; | ||
164 | } | ||
165 | if (NULL != rs->dnsout6) | ||
166 | { | ||
167 | GNUNET_NETWORK_socket_close (rs->dnsout6); | ||
168 | rs->dnsout6 = NULL; | ||
169 | } | ||
170 | if (NULL != rs->read_task) | ||
171 | { | ||
172 | GNUNET_SCHEDULER_cancel (rs->read_task); | ||
173 | rs->read_task = NULL; | ||
174 | } | ||
175 | if (NULL != rs->retry_task) | ||
176 | { | ||
177 | GNUNET_SCHEDULER_cancel (rs->retry_task); | ||
178 | rs->retry_task = NULL; | ||
179 | } | ||
180 | if (NULL != rs->request) | ||
181 | { | ||
182 | GNUNET_free (rs->request); | ||
183 | rs->request = NULL; | ||
184 | } | ||
185 | } | ||
186 | |||
187 | |||
188 | /** | ||
189 | * Open source port for sending DNS requests | ||
190 | * | ||
191 | * @param af AF_INET or AF_INET6 | ||
192 | * @return #GNUNET_OK on success | ||
193 | */ | ||
194 | static struct GNUNET_NETWORK_Handle * | ||
195 | open_socket (int af) | ||
196 | { | ||
197 | struct sockaddr_in a4; | ||
198 | struct sockaddr_in6 a6; | ||
199 | struct sockaddr *sa; | ||
200 | socklen_t alen; | ||
201 | struct GNUNET_NETWORK_Handle *ret; | ||
202 | |||
203 | ret = GNUNET_NETWORK_socket_create (af, SOCK_DGRAM, 0); | ||
204 | if (NULL == ret) | ||
205 | return NULL; | ||
206 | switch (af) | ||
207 | { | ||
208 | case AF_INET: | ||
209 | memset (&a4, 0, alen = sizeof(struct sockaddr_in)); | ||
210 | sa = (struct sockaddr *) &a4; | ||
211 | break; | ||
212 | |||
213 | case AF_INET6: | ||
214 | memset (&a6, 0, alen = sizeof(struct sockaddr_in6)); | ||
215 | sa = (struct sockaddr *) &a6; | ||
216 | break; | ||
217 | |||
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, sa, alen)) | ||
225 | { | ||
226 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
227 | _ ("Could not bind to any port: %s\n"), | ||
228 | strerror (errno)); | ||
229 | GNUNET_NETWORK_socket_close (ret); | ||
230 | return NULL; | ||
231 | } | ||
232 | return ret; | ||
233 | } | ||
234 | |||
235 | |||
236 | /** | ||
237 | * Get a socket of the specified address family to send out a | ||
238 | * UDP DNS request to the Internet. | ||
239 | * | ||
240 | * @param ctx the DNSSTUB context | ||
241 | * @return NULL on error | ||
242 | */ | ||
243 | static struct GNUNET_DNSSTUB_RequestSocket * | ||
244 | get_request_socket (struct GNUNET_DNSSTUB_Context *ctx) | ||
245 | { | ||
246 | struct GNUNET_DNSSTUB_RequestSocket *rs; | ||
247 | |||
248 | for (unsigned int i = 0; i < 256; i++) | ||
249 | { | ||
250 | rs = &ctx->sockets[GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, | ||
251 | ctx->num_sockets)]; | ||
252 | if (NULL == rs->rc) | ||
253 | break; | ||
254 | } | ||
255 | if (NULL != rs->rc) | ||
256 | { | ||
257 | /* signal "failure" */ | ||
258 | rs->rc (rs->rc_cls, NULL, 0); | ||
259 | rs->rc = NULL; | ||
260 | } | ||
261 | if (NULL != rs->read_task) | ||
262 | { | ||
263 | GNUNET_SCHEDULER_cancel (rs->read_task); | ||
264 | rs->read_task = NULL; | ||
265 | } | ||
266 | if (NULL != rs->retry_task) | ||
267 | { | ||
268 | GNUNET_SCHEDULER_cancel (rs->retry_task); | ||
269 | rs->retry_task = NULL; | ||
270 | } | ||
271 | if (NULL != rs->request) | ||
272 | { | ||
273 | GNUNET_free (rs->request); | ||
274 | rs->request = NULL; | ||
275 | } | ||
276 | rs->ctx = ctx; | ||
277 | return rs; | ||
278 | } | ||
279 | |||
280 | |||
281 | /** | ||
282 | * Actually do the reading of a DNS packet from our UDP socket and see | ||
283 | * if we have a valid, matching, pending request. | ||
284 | * | ||
285 | * @param rs request socket with callback details | ||
286 | * @param dnsout socket to read from | ||
287 | * @return #GNUNET_OK on success, #GNUNET_NO on drop, #GNUNET_SYSERR on IO-errors (closed socket) | ||
288 | */ | ||
289 | static int | ||
290 | do_dns_read (struct GNUNET_DNSSTUB_RequestSocket *rs, | ||
291 | struct GNUNET_NETWORK_Handle *dnsout) | ||
292 | { | ||
293 | struct GNUNET_DNSSTUB_Context *ctx = rs->ctx; | ||
294 | ssize_t r; | ||
295 | int len; | ||
296 | |||
297 | if (0 != ioctl (GNUNET_NETWORK_get_fd (dnsout), FIONREAD, &len)) | ||
298 | { | ||
299 | /* conservative choice: */ | ||
300 | len = UINT16_MAX; | ||
301 | } | ||
302 | |||
303 | GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Receiving %d byte DNS reply\n", len); | ||
304 | { | ||
305 | unsigned char buf[len] GNUNET_ALIGN; | ||
306 | int found; | ||
307 | struct sockaddr_storage addr; | ||
308 | socklen_t addrlen; | ||
309 | struct GNUNET_TUN_DnsHeader *dns; | ||
310 | |||
311 | addrlen = sizeof(addr); | ||
312 | memset (&addr, 0, sizeof(addr)); | ||
313 | r = GNUNET_NETWORK_socket_recvfrom (dnsout, | ||
314 | buf, | ||
315 | sizeof(buf), | ||
316 | (struct sockaddr *) &addr, | ||
317 | &addrlen); | ||
318 | if (-1 == r) | ||
319 | { | ||
320 | GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "recvfrom"); | ||
321 | GNUNET_NETWORK_socket_close (dnsout); | ||
322 | return GNUNET_SYSERR; | ||
323 | } | ||
324 | found = GNUNET_NO; | ||
325 | for (struct DnsServer *ds = ctx->dns_head; NULL != ds; ds = ds->next) | ||
326 | { | ||
327 | if (ds->ss.ss_family != addr.ss_family) | ||
328 | continue; | ||
329 | if (addr.ss_family == AF_INET) | ||
330 | { | ||
331 | struct sockaddr_in *v4 = (struct sockaddr_in *) &addr; | ||
332 | struct sockaddr_in *ds_v4 = (struct sockaddr_in *) &ds->ss; | ||
333 | |||
334 | |||
335 | if ((0 == memcmp (&v4->sin_addr, | ||
336 | &ds_v4->sin_addr, | ||
337 | sizeof(struct sockaddr_in))) && | ||
338 | (v4->sin_port == ds_v4->sin_port)) | ||
339 | { | ||
340 | found = GNUNET_YES; | ||
341 | break; | ||
342 | } | ||
343 | } | ||
344 | else | ||
345 | { | ||
346 | struct sockaddr_in6 *v6 = (struct sockaddr_in6 *) &addr; | ||
347 | struct sockaddr_in6 *ds_v6 = (struct sockaddr_in6 *) &ds->ss; | ||
348 | |||
349 | if (0 == memcmp (&v6->sin6_addr, | ||
350 | &ds_v6->sin6_addr, | ||
351 | sizeof (v6->sin6_addr)) && | ||
352 | (v6->sin6_port == ds_v6->sin6_port)) | ||
353 | { | ||
354 | found = GNUNET_YES; | ||
355 | break; | ||
356 | } | ||
357 | |||
358 | } | ||
359 | } | ||
360 | if (GNUNET_NO == found) | ||
361 | { | ||
362 | GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, | ||
363 | "Received DNS response from server we never asked (ignored)\n"); | ||
364 | |||
365 | return GNUNET_NO; | ||
366 | } | ||
367 | if (sizeof(struct GNUNET_TUN_DnsHeader) > (size_t) r) | ||
368 | { | ||
369 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
370 | _ ("Received DNS response that is too small (%u bytes)\n"), | ||
371 | (unsigned int) r); | ||
372 | return GNUNET_NO; | ||
373 | } | ||
374 | dns = (struct GNUNET_TUN_DnsHeader *) buf; | ||
375 | if (NULL == rs->rc) | ||
376 | { | ||
377 | GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, | ||
378 | "Request timeout or cancelled; ignoring reply\n"); | ||
379 | return GNUNET_NO; | ||
380 | } | ||
381 | rs->rc (rs->rc_cls, dns, r); | ||
382 | } | ||
383 | return GNUNET_OK; | ||
384 | } | ||
385 | |||
386 | |||
387 | /** | ||
388 | * Read a DNS response from the (unhindered) UDP-Socket | ||
389 | * | ||
390 | * @param cls socket to read from | ||
391 | */ | ||
392 | static void | ||
393 | read_response (void *cls); | ||
394 | |||
395 | |||
396 | /** | ||
397 | * Schedule #read_response() task for @a rs. | ||
398 | * | ||
399 | * @param rs request to schedule read operation for | ||
400 | */ | ||
401 | static void | ||
402 | schedule_read (struct GNUNET_DNSSTUB_RequestSocket *rs) | ||
403 | { | ||
404 | struct GNUNET_NETWORK_FDSet *rset; | ||
405 | |||
406 | if (NULL != rs->read_task) | ||
407 | GNUNET_SCHEDULER_cancel (rs->read_task); | ||
408 | rset = GNUNET_NETWORK_fdset_create (); | ||
409 | if (NULL != rs->dnsout4) | ||
410 | GNUNET_NETWORK_fdset_set (rset, rs->dnsout4); | ||
411 | if (NULL != rs->dnsout6) | ||
412 | GNUNET_NETWORK_fdset_set (rset, rs->dnsout6); | ||
413 | rs->read_task = | ||
414 | GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT, | ||
415 | GNUNET_TIME_UNIT_FOREVER_REL, | ||
416 | rset, | ||
417 | NULL, | ||
418 | &read_response, | ||
419 | rs); | ||
420 | GNUNET_NETWORK_fdset_destroy (rset); | ||
421 | } | ||
422 | |||
423 | |||
424 | /** | ||
425 | * Read a DNS response from the (unhindered) UDP-Socket | ||
426 | * | ||
427 | * @param cls `struct GNUNET_DNSSTUB_RequestSocket` to read from | ||
428 | */ | ||
429 | static void | ||
430 | read_response (void *cls) | ||
431 | { | ||
432 | struct GNUNET_DNSSTUB_RequestSocket *rs = cls; | ||
433 | const struct GNUNET_SCHEDULER_TaskContext *tc; | ||
434 | |||
435 | rs->read_task = NULL; | ||
436 | tc = GNUNET_SCHEDULER_get_task_context (); | ||
437 | /* read and process ready sockets */ | ||
438 | if ((NULL != rs->dnsout4) && | ||
439 | (GNUNET_NETWORK_fdset_isset (tc->read_ready, rs->dnsout4)) && | ||
440 | (GNUNET_SYSERR == do_dns_read (rs, rs->dnsout4))) | ||
441 | rs->dnsout4 = NULL; | ||
442 | if ((NULL != rs->dnsout6) && | ||
443 | (GNUNET_NETWORK_fdset_isset (tc->read_ready, rs->dnsout6)) && | ||
444 | (GNUNET_SYSERR == do_dns_read (rs, rs->dnsout6))) | ||
445 | rs->dnsout6 = NULL; | ||
446 | /* re-schedule read task */ | ||
447 | schedule_read (rs); | ||
448 | } | ||
449 | |||
450 | |||
451 | /** | ||
452 | * Task to (re)transmit the DNS query, possibly repeatedly until | ||
453 | * we succeed. | ||
454 | * | ||
455 | * @param cls our `struct GNUNET_DNSSTUB_RequestSocket *` | ||
456 | */ | ||
457 | static void | ||
458 | transmit_query (void *cls) | ||
459 | { | ||
460 | struct GNUNET_DNSSTUB_RequestSocket *rs = cls; | ||
461 | struct GNUNET_DNSSTUB_Context *ctx = rs->ctx; | ||
462 | const struct sockaddr *sa; | ||
463 | socklen_t salen; | ||
464 | struct DnsServer *ds; | ||
465 | struct GNUNET_NETWORK_Handle *dnsout; | ||
466 | |||
467 | rs->retry_task = | ||
468 | GNUNET_SCHEDULER_add_delayed (ctx->retry_freq, &transmit_query, 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 | |||
485 | case AF_INET6: | ||
486 | if (NULL == rs->dnsout6) | ||
487 | rs->dnsout6 = open_socket (AF_INET6); | ||
488 | dnsout = rs->dnsout6; | ||
489 | sa = (const struct sockaddr *) &ds->ss; | ||
490 | salen = sizeof(struct sockaddr_in6); | ||
491 | break; | ||
492 | |||
493 | default: | ||
494 | return; | ||
495 | } | ||
496 | if (NULL == dnsout) | ||
497 | { | ||
498 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
499 | "Unable to use configure DNS server, skipping\n"); | ||
500 | return; | ||
501 | } | ||
502 | if (GNUNET_SYSERR == GNUNET_NETWORK_socket_sendto (dnsout, | ||
503 | rs->request, | ||
504 | rs->request_len, | ||
505 | sa, | ||
506 | salen)) | ||
507 | GNUNET_log (GNUNET_ERROR_TYPE_WARNING, | ||
508 | _ ("Failed to send DNS request to %s: %s\n"), | ||
509 | GNUNET_a2s (sa, salen), | ||
510 | strerror (errno)); | ||
511 | else | ||
512 | GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, | ||
513 | _ ("Sent DNS request to %s\n"), | ||
514 | GNUNET_a2s (sa, salen)); | ||
515 | schedule_read (rs); | ||
516 | } | ||
517 | |||
518 | |||
519 | /** | ||
520 | * Perform DNS resolution using our default IP from init. | ||
521 | * | ||
522 | * @param ctx stub resolver to use | ||
523 | * @param request DNS request to transmit | ||
524 | * @param request_len number of bytes in msg | ||
525 | * @param rc function to call with result | ||
526 | * @param rc_cls closure for 'rc' | ||
527 | * @return socket used for the request, NULL on error | ||
528 | */ | ||
529 | struct GNUNET_DNSSTUB_RequestSocket * | ||
530 | GNUNET_DNSSTUB_resolve (struct GNUNET_DNSSTUB_Context *ctx, | ||
531 | const void *request, | ||
532 | size_t request_len, | ||
533 | GNUNET_DNSSTUB_ResultCallback rc, | ||
534 | void *rc_cls) | ||
535 | { | ||
536 | struct GNUNET_DNSSTUB_RequestSocket *rs; | ||
537 | |||
538 | if (NULL == ctx->dns_head) | ||
539 | { | ||
540 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
541 | "No DNS server configured for resolution\n"); | ||
542 | return NULL; | ||
543 | } | ||
544 | if (NULL == (rs = get_request_socket (ctx))) | ||
545 | { | ||
546 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
547 | "No request socket available for DNS resolution\n"); | ||
548 | return NULL; | ||
549 | } | ||
550 | rs->ds_pos = ctx->dns_head; | ||
551 | rs->rc = rc; | ||
552 | rs->rc_cls = rc_cls; | ||
553 | rs->request = GNUNET_memdup (request, request_len); | ||
554 | rs->request_len = request_len; | ||
555 | rs->retry_task = GNUNET_SCHEDULER_add_now (&transmit_query, rs); | ||
556 | return rs; | ||
557 | } | ||
558 | |||
559 | |||
560 | /** | ||
561 | * Cancel DNS resolution. | ||
562 | * | ||
563 | * @param rs resolution to cancel | ||
564 | */ | ||
565 | void | ||
566 | GNUNET_DNSSTUB_resolve_cancel (struct GNUNET_DNSSTUB_RequestSocket *rs) | ||
567 | { | ||
568 | rs->rc = NULL; | ||
569 | if (NULL != rs->retry_task) | ||
570 | { | ||
571 | GNUNET_SCHEDULER_cancel (rs->retry_task); | ||
572 | rs->retry_task = NULL; | ||
573 | } | ||
574 | if (NULL != rs->read_task) | ||
575 | { | ||
576 | GNUNET_SCHEDULER_cancel (rs->read_task); | ||
577 | rs->read_task = NULL; | ||
578 | } | ||
579 | } | ||
580 | |||
581 | |||
582 | /** | ||
583 | * Start a DNS stub resolver. | ||
584 | * | ||
585 | * @param num_sockets how many sockets should we open | ||
586 | * in parallel for DNS queries for this stub? | ||
587 | * @return NULL on error | ||
588 | */ | ||
589 | struct GNUNET_DNSSTUB_Context * | ||
590 | GNUNET_DNSSTUB_start (unsigned int num_sockets) | ||
591 | { | ||
592 | struct GNUNET_DNSSTUB_Context *ctx; | ||
593 | |||
594 | if (0 == num_sockets) | ||
595 | { | ||
596 | GNUNET_break (0); | ||
597 | return NULL; | ||
598 | } | ||
599 | ctx = GNUNET_new (struct GNUNET_DNSSTUB_Context); | ||
600 | ctx->num_sockets = num_sockets; | ||
601 | ctx->sockets = | ||
602 | GNUNET_new_array (num_sockets, struct GNUNET_DNSSTUB_RequestSocket); | ||
603 | ctx->retry_freq = DNS_RETRANSMIT_DELAY; | ||
604 | return ctx; | ||
605 | } | ||
606 | |||
607 | |||
608 | /** | ||
609 | * Add nameserver for use by the DNSSTUB. We will use | ||
610 | * all provided nameservers for resolution (round-robin). | ||
611 | * | ||
612 | * @param ctx resolver context to modify | ||
613 | * @param dns_ip target IP address to use (as string) | ||
614 | * @return #GNUNET_OK on success | ||
615 | */ | ||
616 | int | ||
617 | GNUNET_DNSSTUB_add_dns_ip (struct GNUNET_DNSSTUB_Context *ctx, | ||
618 | const char *dns_ip) | ||
619 | { | ||
620 | struct DnsServer *ds; | ||
621 | struct in_addr i4; | ||
622 | struct in6_addr i6; | ||
623 | |||
624 | ds = GNUNET_new (struct DnsServer); | ||
625 | if (1 == inet_pton (AF_INET, dns_ip, &i4)) | ||
626 | { | ||
627 | struct sockaddr_in *s4 = (struct sockaddr_in *) &ds->ss; | ||
628 | |||
629 | s4->sin_family = AF_INET; | ||
630 | s4->sin_port = htons (53); | ||
631 | s4->sin_addr = i4; | ||
632 | #if HAVE_SOCKADDR_IN_SIN_LEN | ||
633 | s4->sin_len = (u_char) sizeof(struct sockaddr_in); | ||
634 | #endif | ||
635 | } | ||
636 | else if (1 == inet_pton (AF_INET6, dns_ip, &i6)) | ||
637 | { | ||
638 | struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) &ds->ss; | ||
639 | |||
640 | s6->sin6_family = AF_INET6; | ||
641 | s6->sin6_port = htons (53); | ||
642 | s6->sin6_addr = i6; | ||
643 | #if HAVE_SOCKADDR_IN_SIN_LEN | ||
644 | s6->sin6_len = (u_char) sizeof(struct sockaddr_in6); | ||
645 | #endif | ||
646 | } | ||
647 | else | ||
648 | { | ||
649 | GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, | ||
650 | "Malformed IP address `%s' for DNS server\n", | ||
651 | dns_ip); | ||
652 | GNUNET_free (ds); | ||
653 | return GNUNET_SYSERR; | ||
654 | } | ||
655 | GNUNET_CONTAINER_DLL_insert (ctx->dns_head, ctx->dns_tail, ds); | ||
656 | return GNUNET_OK; | ||
657 | } | ||
658 | |||
659 | |||
660 | /** | ||
661 | * Add nameserver for use by the DNSSTUB. We will use | ||
662 | * all provided nameservers for resolution (round-robin). | ||
663 | * | ||
664 | * @param ctx resolver context to modify | ||
665 | * @param sa socket address of DNS resolver to use | ||
666 | * @return #GNUNET_OK on success | ||
667 | */ | ||
668 | int | ||
669 | GNUNET_DNSSTUB_add_dns_sa (struct GNUNET_DNSSTUB_Context *ctx, | ||
670 | const struct sockaddr *sa) | ||
671 | { | ||
672 | struct DnsServer *ds; | ||
673 | |||
674 | ds = GNUNET_new (struct DnsServer); | ||
675 | switch (sa->sa_family) | ||
676 | { | ||
677 | case AF_INET : | ||
678 | GNUNET_memcpy (&ds->ss, sa, sizeof(struct sockaddr_in)); | ||
679 | break; | ||
680 | |||
681 | case AF_INET6: | ||
682 | GNUNET_memcpy (&ds->ss, sa, sizeof(struct sockaddr_in6)); | ||
683 | break; | ||
684 | |||
685 | default: | ||
686 | GNUNET_break (0); | ||
687 | GNUNET_free (ds); | ||
688 | return GNUNET_SYSERR; | ||
689 | } | ||
690 | GNUNET_CONTAINER_DLL_insert (ctx->dns_head, ctx->dns_tail, ds); | ||
691 | return GNUNET_OK; | ||
692 | } | ||
693 | |||
694 | |||
695 | /** | ||
696 | * How long should we try requests before timing out? | ||
697 | * Only effective for requests issued after this call. | ||
698 | * | ||
699 | * @param ctx resolver context to modify | ||
700 | * @param retry_freq how long to wait between retries | ||
701 | */ | ||
702 | void | ||
703 | GNUNET_DNSSTUB_set_retry (struct GNUNET_DNSSTUB_Context *ctx, | ||
704 | struct GNUNET_TIME_Relative retry_freq) | ||
705 | { | ||
706 | ctx->retry_freq = retry_freq; | ||
707 | } | ||
708 | |||
709 | |||
710 | /** | ||
711 | * Cleanup DNSSTUB resolver. | ||
712 | * | ||
713 | * @param ctx stub resolver to clean up | ||
714 | */ | ||
715 | void | ||
716 | GNUNET_DNSSTUB_stop (struct GNUNET_DNSSTUB_Context *ctx) | ||
717 | { | ||
718 | struct DnsServer *ds; | ||
719 | |||
720 | while (NULL != (ds = ctx->dns_head)) | ||
721 | { | ||
722 | GNUNET_CONTAINER_DLL_remove (ctx->dns_head, ctx->dns_tail, ds); | ||
723 | GNUNET_free (ds); | ||
724 | } | ||
725 | for (unsigned int i = 0; i < ctx->num_sockets; i++) | ||
726 | cleanup_rs (&ctx->sockets[i]); | ||
727 | GNUNET_free (ctx->sockets); | ||
728 | GNUNET_free (ctx); | ||
729 | } | ||
730 | |||
731 | |||
732 | /* end of dnsstub.c */ | ||