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13 Affero General Public License for more details.
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19 * @file gnunet-dns2gns.c
20 * @brief DNS server that translates DNS requests to GNS
21 * @author Christian Grothoff
24 #include <gnunet_util_lib.h>
25 #include <gnunet_dnsparser_lib.h>
26 #include <gnunet_gns_service.h>
27 #include <gnunet_dnsstub_lib.h>
31 * Timeout for DNS requests.
33 #define TIMEOUT GNUNET_TIME_UNIT_MINUTES
36 * Data kept per request.
41 * Socket to use for sending the reply.
43 struct GNUNET_NETWORK_Handle *lsock;
46 * Destination address to use.
51 * Initially, this is the DNS request, it will then be
52 * converted to the DNS response.
54 struct GNUNET_DNSPARSER_Packet *packet;
57 * Our GNS request handle.
59 struct GNUNET_GNS_LookupWithTldRequest *lookup;
62 * Our DNS request handle
64 struct GNUNET_DNSSTUB_RequestSocket *dns_lookup;
67 * Task run on timeout or shutdown to clean up without
70 struct GNUNET_SCHEDULER_Task *timeout_task;
73 * Original UDP request message.
78 * Number of bytes in @e addr.
83 * Number of bytes in @e udp_msg.
88 * ID of the original request.
90 uint16_t original_request_id;
95 * Handle to GNS resolver.
97 struct GNUNET_GNS_Handle *gns;
102 struct GNUNET_DNSSTUB_Context *dns_stub;
105 * Listen socket for IPv4.
107 static struct GNUNET_NETWORK_Handle *listen_socket4;
110 * Listen socket for IPv6.
112 static struct GNUNET_NETWORK_Handle *listen_socket6;
115 * Task for IPv4 socket.
117 static struct GNUNET_SCHEDULER_Task *t4;
120 * Task for IPv6 socket.
122 static struct GNUNET_SCHEDULER_Task *t6;
130 * UDP Port we listen on for inbound DNS requests.
132 static unsigned int listen_port = 53;
135 * Configuration to use.
137 static const struct GNUNET_CONFIGURATION_Handle *cfg;
141 * Task run on shutdown. Cleans up everything.
146 do_shutdown (void *cls)
151 GNUNET_SCHEDULER_cancel (t4);
156 GNUNET_SCHEDULER_cancel (t6);
159 if (NULL != listen_socket4)
161 GNUNET_NETWORK_socket_close (listen_socket4);
162 listen_socket4 = NULL;
164 if (NULL != listen_socket6)
166 GNUNET_NETWORK_socket_close (listen_socket6);
167 listen_socket6 = NULL;
171 GNUNET_GNS_disconnect (gns);
174 if (NULL != dns_stub)
176 GNUNET_DNSSTUB_stop (dns_stub);
183 * Send the response for the given request and clean up.
185 * @param request context for the request.
188 send_response (struct Request *request)
195 GNUNET_DNSPARSER_pack (request->packet,
196 UINT16_MAX /* is this not too much? */,
200 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
201 _("Failed to pack DNS response into UDP packet!\n"));
205 sret = GNUNET_NETWORK_socket_sendto (request->lsock,
211 (size != (size_t) sret) )
212 GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
216 GNUNET_SCHEDULER_cancel (request->timeout_task);
217 GNUNET_DNSPARSER_free_packet (request->packet);
218 GNUNET_free (request->udp_msg);
219 GNUNET_free (request);
224 * Task run on timeout. Cleans up request.
226 * @param cls `struct Request *` of the request to clean up
229 do_timeout (void *cls)
231 struct Request *request = cls;
233 if (NULL != request->packet)
234 GNUNET_DNSPARSER_free_packet (request->packet);
235 if (NULL != request->lookup)
236 GNUNET_GNS_lookup_with_tld_cancel (request->lookup);
237 if (NULL != request->dns_lookup)
238 GNUNET_DNSSTUB_resolve_cancel (request->dns_lookup);
239 GNUNET_free (request->udp_msg);
240 GNUNET_free (request);
245 * Iterator called on obtained result for a DNS lookup
248 * @param dns the DNS udp payload
249 * @param r size of the DNS payload
252 dns_result_processor (void *cls,
253 const struct GNUNET_TUN_DnsHeader *dns,
256 struct Request *request = cls;
260 /* DNSSTUB gave up, so we trigger timeout early */
261 GNUNET_SCHEDULER_cancel (request->timeout_task);
262 do_timeout (request);
265 if (request->original_request_id != dns->id)
267 /* for a another query, ignore */
270 request->packet = GNUNET_DNSPARSER_parse ((char*)dns,
272 send_response (request);
277 * Iterator called on obtained result for a GNS lookup.
280 * @param was_gns #GNUNET_NO if the TLD is not configured for GNS
281 * @param rd_count number of records in @a rd
282 * @param rd the records in reply
285 result_processor (void *cls,
288 const struct GNUNET_GNSRECORD_Data *rd)
290 struct Request *request = cls;
291 struct GNUNET_DNSPARSER_Packet *packet;
292 struct GNUNET_DNSPARSER_Record rec;
294 request->lookup = NULL;
295 if (GNUNET_NO == was_gns)
297 /* TLD not configured for GNS, fall back to DNS */
298 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
299 "Using DNS resolver IP `%s' to resolve `%s'\n",
301 request->packet->queries[0].name);
302 request->original_request_id = request->packet->id;
303 GNUNET_DNSPARSER_free_packet (request->packet);
304 request->packet = NULL;
305 request->dns_lookup = GNUNET_DNSSTUB_resolve (dns_stub,
307 request->udp_msg_size,
308 &dns_result_processor,
312 packet = request->packet;
313 packet->flags.query_or_response = 1;
314 packet->flags.return_code = GNUNET_TUN_DNS_RETURN_CODE_NO_ERROR;
315 packet->flags.checking_disabled = 0;
316 packet->flags.authenticated_data = 1;
317 packet->flags.zero = 0;
318 packet->flags.recursion_available = 1;
319 packet->flags.message_truncated = 0;
320 packet->flags.authoritative_answer = 0;
321 //packet->flags.opcode = GNUNET_TUN_DNS_OPCODE_STATUS; // ???
322 for (uint32_t i=0;i<rd_count;i++)
324 // FIXME: do we need to hanlde #GNUNET_GNSRECORD_RF_SHADOW_RECORD
325 // here? Or should we do this in libgnunetgns?
326 rec.expiration_time.abs_value_us = rd[i].expiration_time;
327 switch (rd[i].record_type)
329 case GNUNET_DNSPARSER_TYPE_A:
330 GNUNET_assert (sizeof (struct in_addr) == rd[i].data_size);
331 rec.name = GNUNET_strdup (packet->queries[0].name);
332 rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
333 rec.type = GNUNET_DNSPARSER_TYPE_A;
334 rec.data.raw.data = GNUNET_new (struct in_addr);
335 GNUNET_memcpy (rec.data.raw.data,
338 rec.data.raw.data_len = sizeof (struct in_addr);
339 GNUNET_array_append (packet->answers,
343 case GNUNET_DNSPARSER_TYPE_AAAA:
344 GNUNET_assert (sizeof (struct in6_addr) == rd[i].data_size);
345 rec.name = GNUNET_strdup (packet->queries[0].name);
346 rec.data.raw.data = GNUNET_new (struct in6_addr);
347 rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
348 rec.type = GNUNET_DNSPARSER_TYPE_AAAA;
349 GNUNET_memcpy (rec.data.raw.data,
352 rec.data.raw.data_len = sizeof (struct in6_addr);
353 GNUNET_array_append (packet->answers,
357 case GNUNET_DNSPARSER_TYPE_CNAME:
358 rec.name = GNUNET_strdup (packet->queries[0].name);
359 rec.data.hostname = GNUNET_strdup (rd[i].data);
360 rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
361 rec.type = GNUNET_DNSPARSER_TYPE_CNAME;
362 GNUNET_memcpy (rec.data.hostname,
365 GNUNET_array_append (packet->answers,
374 send_response (request);
379 * Handle DNS request.
381 * @param lsock socket to use for sending the reply
382 * @param addr address to use for sending the reply
383 * @param addr_len number of bytes in @a addr
384 * @param udp_msg DNS request payload
385 * @param udp_msg_size number of bytes in @a udp_msg
388 handle_request (struct GNUNET_NETWORK_Handle *lsock,
394 struct Request *request;
395 struct GNUNET_DNSPARSER_Packet *packet;
397 packet = GNUNET_DNSPARSER_parse (udp_msg,
401 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
402 _("Cannot parse DNS request from %s\n"),
403 GNUNET_a2s (addr, addr_len));
406 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
407 "Received request for `%s' with flags %u, #answers %d, #auth %d, #additional %d\n",
408 packet->queries[0].name,
409 (unsigned int) packet->flags.query_or_response,
410 (int) packet->num_answers,
411 (int) packet->num_authority_records,
412 (int) packet->num_additional_records);
413 if ( (0 != packet->flags.query_or_response) ||
414 (0 != packet->num_answers) ||
415 (0 != packet->num_authority_records))
417 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
418 _("Received malformed DNS request from %s\n"),
419 GNUNET_a2s (addr, addr_len));
420 GNUNET_DNSPARSER_free_packet (packet);
423 if ( (1 != packet->num_queries) )
425 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
426 _("Received unsupported DNS request from %s\n"),
429 GNUNET_DNSPARSER_free_packet (packet);
432 request = GNUNET_malloc (sizeof (struct Request) + addr_len);
433 request->lsock = lsock;
434 request->packet = packet;
435 request->addr = &request[1];
436 request->addr_len = addr_len;
437 GNUNET_memcpy (&request[1],
440 request->udp_msg_size = udp_msg_size;
441 request->udp_msg = GNUNET_memdup (udp_msg,
443 request->timeout_task = GNUNET_SCHEDULER_add_delayed (TIMEOUT,
446 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
447 "Calling GNS on `%s'\n",
448 packet->queries[0].name);
449 request->lookup = GNUNET_GNS_lookup_with_tld (gns,
450 packet->queries[0].name,
451 packet->queries[0].type,
459 * Task to read IPv4 DNS packets.
461 * @param cls the 'listen_socket4'
464 read_dns4 (void *cls)
466 struct sockaddr_in v4;
469 const struct GNUNET_SCHEDULER_TaskContext *tc;
471 GNUNET_assert (listen_socket4 == cls);
472 t4 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
476 tc = GNUNET_SCHEDULER_get_task_context ();
477 if (0 == (GNUNET_SCHEDULER_REASON_READ_READY & tc->reason))
478 return; /* shutdown? */
479 size = GNUNET_NETWORK_socket_recvfrom_amount (listen_socket4);
483 return; /* read error!? */
489 addrlen = sizeof (v4);
490 sret = GNUNET_NETWORK_socket_recvfrom (listen_socket4,
493 (struct sockaddr *) &v4,
497 GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
501 GNUNET_break (size == sret);
502 handle_request (listen_socket4,
512 * Task to read IPv6 DNS packets.
514 * @param cls the 'listen_socket6'
517 read_dns6 (void *cls)
519 struct sockaddr_in6 v6;
522 const struct GNUNET_SCHEDULER_TaskContext *tc;
524 GNUNET_assert (listen_socket6 == cls);
525 t6 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
529 tc = GNUNET_SCHEDULER_get_task_context ();
530 if (0 == (GNUNET_SCHEDULER_REASON_READ_READY & tc->reason))
531 return; /* shutdown? */
532 size = GNUNET_NETWORK_socket_recvfrom_amount (listen_socket6);
536 return; /* read error!? */
542 addrlen = sizeof (v6);
543 sret = GNUNET_NETWORK_socket_recvfrom (listen_socket6,
546 (struct sockaddr *) &v6,
550 GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
554 GNUNET_break (size == sret);
555 handle_request (listen_socket6,
565 * Main function that will be run.
568 * @param args remaining command-line arguments
569 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
570 * @param c configuration
576 const struct GNUNET_CONFIGURATION_Handle *c)
584 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
585 _("No DNS server specified!\n"));
588 GNUNET_SCHEDULER_add_shutdown (&do_shutdown,
590 if (NULL == (gns = GNUNET_GNS_connect (cfg)))
592 GNUNET_assert (NULL != (dns_stub = GNUNET_DNSSTUB_start (128)));
594 GNUNET_DNSSTUB_add_dns_ip (dns_stub,
597 GNUNET_DNSSTUB_stop (dns_stub);
598 GNUNET_GNS_disconnect (gns);
602 listen_socket4 = GNUNET_NETWORK_socket_create (PF_INET,
605 if (NULL != listen_socket4)
607 struct sockaddr_in v4;
609 memset (&v4, 0, sizeof (v4));
610 v4.sin_family = AF_INET;
611 #if HAVE_SOCKADDR_IN_SIN_LEN
612 v4.sin_len = sizeof (v4);
614 v4.sin_port = htons (listen_port);
616 GNUNET_NETWORK_socket_bind (listen_socket4,
617 (struct sockaddr *) &v4,
620 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
621 GNUNET_NETWORK_socket_close (listen_socket4);
622 listen_socket4 = NULL;
625 listen_socket6 = GNUNET_NETWORK_socket_create (PF_INET6,
628 if (NULL != listen_socket6)
630 struct sockaddr_in6 v6;
632 memset (&v6, 0, sizeof (v6));
633 v6.sin6_family = AF_INET6;
634 #if HAVE_SOCKADDR_IN_SIN_LEN
635 v6.sin6_len = sizeof (v6);
637 v6.sin6_port = htons (listen_port);
639 GNUNET_NETWORK_socket_bind (listen_socket6,
640 (struct sockaddr *) &v6,
643 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
644 GNUNET_NETWORK_socket_close (listen_socket6);
645 listen_socket6 = NULL;
648 if ( (NULL == listen_socket4) &&
649 (NULL == listen_socket6) )
651 GNUNET_GNS_disconnect (gns);
653 GNUNET_DNSSTUB_stop (dns_stub);
657 if (NULL != listen_socket4)
658 t4 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
662 if (NULL != listen_socket6)
663 t6 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
671 * The main function for the dns2gns daemon.
673 * @param argc number of arguments from the command line
674 * @param argv command line arguments
675 * @return 0 ok, 1 on error
681 struct GNUNET_GETOPT_CommandLineOption options[] = {
682 GNUNET_GETOPT_option_string ('d',
685 gettext_noop ("IP of recursive DNS resolver to use (required)"),
687 GNUNET_GETOPT_option_uint ('p',
690 gettext_noop ("UDP port to listen on for inbound DNS requests; default: 2853"),
692 GNUNET_GETOPT_OPTION_END
697 GNUNET_STRINGS_get_utf8_args (argc, argv,
700 GNUNET_log_setup ("gnunet-dns2gns",
705 GNUNET_PROGRAM_run (argc, argv,
707 _("GNUnet DNS-to-GNS proxy (a DNS server)"),
709 &run, NULL)) ? 0 : 1;
710 GNUNET_free ((void*) argv);
714 /* end of gnunet-dns2gns.c */