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3 Copyright (C) 2012-2013 GNUnet e.V.
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6 under the terms of the GNU General Public License as published
7 by the Free Software Foundation, either version 3 of the License,
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
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13 Affero General Public License for more details.
16 * @file gnunet-dns2gns.c
17 * @brief DNS server that translates DNS requests to GNS
18 * @author Christian Grothoff
21 #include <gnunet_util_lib.h>
22 #include <gnunet_dnsparser_lib.h>
23 #include <gnunet_gns_service.h>
24 #include <gnunet_dnsstub_lib.h>
28 * Timeout for DNS requests.
30 #define TIMEOUT GNUNET_TIME_UNIT_MINUTES
33 * Data kept per request.
38 * Socket to use for sending the reply.
40 struct GNUNET_NETWORK_Handle *lsock;
43 * Destination address to use.
48 * Initially, this is the DNS request, it will then be
49 * converted to the DNS response.
51 struct GNUNET_DNSPARSER_Packet *packet;
54 * Our GNS request handle.
56 struct GNUNET_GNS_LookupWithTldRequest *lookup;
59 * Our DNS request handle
61 struct GNUNET_DNSSTUB_RequestSocket *dns_lookup;
64 * Task run on timeout or shutdown to clean up without
67 struct GNUNET_SCHEDULER_Task *timeout_task;
70 * Original UDP request message.
75 * Number of bytes in @e addr.
80 * Number of bytes in @e udp_msg.
85 * ID of the original request.
87 uint16_t original_request_id;
92 * Handle to GNS resolver.
94 struct GNUNET_GNS_Handle *gns;
99 struct GNUNET_DNSSTUB_Context *dns_stub;
102 * Listen socket for IPv4.
104 static struct GNUNET_NETWORK_Handle *listen_socket4;
107 * Listen socket for IPv6.
109 static struct GNUNET_NETWORK_Handle *listen_socket6;
112 * Task for IPv4 socket.
114 static struct GNUNET_SCHEDULER_Task *t4;
117 * Task for IPv6 socket.
119 static struct GNUNET_SCHEDULER_Task *t6;
127 * UDP Port we listen on for inbound DNS requests.
129 static unsigned int listen_port = 53;
132 * Configuration to use.
134 static const struct GNUNET_CONFIGURATION_Handle *cfg;
138 * Task run on shutdown. Cleans up everything.
143 do_shutdown (void *cls)
148 GNUNET_SCHEDULER_cancel (t4);
153 GNUNET_SCHEDULER_cancel (t6);
156 if (NULL != listen_socket4)
158 GNUNET_NETWORK_socket_close (listen_socket4);
159 listen_socket4 = NULL;
161 if (NULL != listen_socket6)
163 GNUNET_NETWORK_socket_close (listen_socket6);
164 listen_socket6 = NULL;
168 GNUNET_GNS_disconnect (gns);
171 if (NULL != dns_stub)
173 GNUNET_DNSSTUB_stop (dns_stub);
180 * Send the response for the given request and clean up.
182 * @param request context for the request.
185 send_response (struct Request *request)
192 GNUNET_DNSPARSER_pack (request->packet,
193 UINT16_MAX /* is this not too much? */,
197 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
198 _("Failed to pack DNS response into UDP packet!\n"));
202 sret = GNUNET_NETWORK_socket_sendto (request->lsock,
208 (size != (size_t) sret) )
209 GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
213 GNUNET_SCHEDULER_cancel (request->timeout_task);
214 GNUNET_DNSPARSER_free_packet (request->packet);
215 GNUNET_free (request->udp_msg);
216 GNUNET_free (request);
221 * Task run on timeout. Cleans up request.
223 * @param cls `struct Request *` of the request to clean up
226 do_timeout (void *cls)
228 struct Request *request = cls;
230 if (NULL != request->packet)
231 GNUNET_DNSPARSER_free_packet (request->packet);
232 if (NULL != request->lookup)
233 GNUNET_GNS_lookup_with_tld_cancel (request->lookup);
234 if (NULL != request->dns_lookup)
235 GNUNET_DNSSTUB_resolve_cancel (request->dns_lookup);
236 GNUNET_free (request->udp_msg);
237 GNUNET_free (request);
242 * Iterator called on obtained result for a DNS lookup
245 * @param dns the DNS udp payload
246 * @param r size of the DNS payload
249 dns_result_processor (void *cls,
250 const struct GNUNET_TUN_DnsHeader *dns,
253 struct Request *request = cls;
257 /* DNSSTUB gave up, so we trigger timeout early */
258 GNUNET_SCHEDULER_cancel (request->timeout_task);
259 do_timeout (request);
262 if (request->original_request_id != dns->id)
264 /* for a another query, ignore */
267 request->packet = GNUNET_DNSPARSER_parse ((char*)dns,
269 send_response (request);
274 * Iterator called on obtained result for a GNS lookup.
277 * @param was_gns #GNUNET_NO if the TLD is not configured for GNS
278 * @param rd_count number of records in @a rd
279 * @param rd the records in reply
282 result_processor (void *cls,
285 const struct GNUNET_GNSRECORD_Data *rd)
287 struct Request *request = cls;
288 struct GNUNET_DNSPARSER_Packet *packet;
289 struct GNUNET_DNSPARSER_Record rec;
291 request->lookup = NULL;
292 if (GNUNET_NO == was_gns)
294 /* TLD not configured for GNS, fall back to DNS */
295 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
296 "Using DNS resolver IP `%s' to resolve `%s'\n",
298 request->packet->queries[0].name);
299 request->original_request_id = request->packet->id;
300 GNUNET_DNSPARSER_free_packet (request->packet);
301 request->packet = NULL;
302 request->dns_lookup = GNUNET_DNSSTUB_resolve (dns_stub,
304 request->udp_msg_size,
305 &dns_result_processor,
309 packet = request->packet;
310 packet->flags.query_or_response = 1;
311 packet->flags.return_code = GNUNET_TUN_DNS_RETURN_CODE_NO_ERROR;
312 packet->flags.checking_disabled = 0;
313 packet->flags.authenticated_data = 1;
314 packet->flags.zero = 0;
315 packet->flags.recursion_available = 1;
316 packet->flags.message_truncated = 0;
317 packet->flags.authoritative_answer = 0;
318 //packet->flags.opcode = GNUNET_TUN_DNS_OPCODE_STATUS; // ???
319 for (uint32_t i=0;i<rd_count;i++)
321 // FIXME: do we need to hanlde #GNUNET_GNSRECORD_RF_SHADOW_RECORD
322 // here? Or should we do this in libgnunetgns?
323 rec.expiration_time.abs_value_us = rd[i].expiration_time;
324 switch (rd[i].record_type)
326 case GNUNET_DNSPARSER_TYPE_A:
327 GNUNET_assert (sizeof (struct in_addr) == rd[i].data_size);
328 rec.name = GNUNET_strdup (packet->queries[0].name);
329 rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
330 rec.type = GNUNET_DNSPARSER_TYPE_A;
331 rec.data.raw.data = GNUNET_new (struct in_addr);
332 GNUNET_memcpy (rec.data.raw.data,
335 rec.data.raw.data_len = sizeof (struct in_addr);
336 GNUNET_array_append (packet->answers,
340 case GNUNET_DNSPARSER_TYPE_AAAA:
341 GNUNET_assert (sizeof (struct in6_addr) == rd[i].data_size);
342 rec.name = GNUNET_strdup (packet->queries[0].name);
343 rec.data.raw.data = GNUNET_new (struct in6_addr);
344 rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
345 rec.type = GNUNET_DNSPARSER_TYPE_AAAA;
346 GNUNET_memcpy (rec.data.raw.data,
349 rec.data.raw.data_len = sizeof (struct in6_addr);
350 GNUNET_array_append (packet->answers,
354 case GNUNET_DNSPARSER_TYPE_CNAME:
355 rec.name = GNUNET_strdup (packet->queries[0].name);
356 rec.data.hostname = GNUNET_strdup (rd[i].data);
357 rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
358 rec.type = GNUNET_DNSPARSER_TYPE_CNAME;
359 GNUNET_memcpy (rec.data.hostname,
362 GNUNET_array_append (packet->answers,
371 send_response (request);
376 * Handle DNS request.
378 * @param lsock socket to use for sending the reply
379 * @param addr address to use for sending the reply
380 * @param addr_len number of bytes in @a addr
381 * @param udp_msg DNS request payload
382 * @param udp_msg_size number of bytes in @a udp_msg
385 handle_request (struct GNUNET_NETWORK_Handle *lsock,
391 struct Request *request;
392 struct GNUNET_DNSPARSER_Packet *packet;
394 packet = GNUNET_DNSPARSER_parse (udp_msg,
398 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
399 _("Cannot parse DNS request from %s\n"),
400 GNUNET_a2s (addr, addr_len));
403 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
404 "Received request for `%s' with flags %u, #answers %d, #auth %d, #additional %d\n",
405 packet->queries[0].name,
406 (unsigned int) packet->flags.query_or_response,
407 (int) packet->num_answers,
408 (int) packet->num_authority_records,
409 (int) packet->num_additional_records);
410 if ( (0 != packet->flags.query_or_response) ||
411 (0 != packet->num_answers) ||
412 (0 != packet->num_authority_records))
414 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
415 _("Received malformed DNS request from %s\n"),
416 GNUNET_a2s (addr, addr_len));
417 GNUNET_DNSPARSER_free_packet (packet);
420 if ( (1 != packet->num_queries) )
422 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
423 _("Received unsupported DNS request from %s\n"),
426 GNUNET_DNSPARSER_free_packet (packet);
429 request = GNUNET_malloc (sizeof (struct Request) + addr_len);
430 request->lsock = lsock;
431 request->packet = packet;
432 request->addr = &request[1];
433 request->addr_len = addr_len;
434 GNUNET_memcpy (&request[1],
437 request->udp_msg_size = udp_msg_size;
438 request->udp_msg = GNUNET_memdup (udp_msg,
440 request->timeout_task = GNUNET_SCHEDULER_add_delayed (TIMEOUT,
443 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
444 "Calling GNS on `%s'\n",
445 packet->queries[0].name);
446 request->lookup = GNUNET_GNS_lookup_with_tld (gns,
447 packet->queries[0].name,
448 packet->queries[0].type,
456 * Task to read IPv4 DNS packets.
458 * @param cls the 'listen_socket4'
461 read_dns4 (void *cls)
463 struct sockaddr_in v4;
466 const struct GNUNET_SCHEDULER_TaskContext *tc;
468 GNUNET_assert (listen_socket4 == cls);
469 t4 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
473 tc = GNUNET_SCHEDULER_get_task_context ();
474 if (0 == (GNUNET_SCHEDULER_REASON_READ_READY & tc->reason))
475 return; /* shutdown? */
476 size = GNUNET_NETWORK_socket_recvfrom_amount (listen_socket4);
480 return; /* read error!? */
486 addrlen = sizeof (v4);
487 sret = GNUNET_NETWORK_socket_recvfrom (listen_socket4,
490 (struct sockaddr *) &v4,
494 GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
498 GNUNET_break (size == sret);
499 handle_request (listen_socket4,
509 * Task to read IPv6 DNS packets.
511 * @param cls the 'listen_socket6'
514 read_dns6 (void *cls)
516 struct sockaddr_in6 v6;
519 const struct GNUNET_SCHEDULER_TaskContext *tc;
521 GNUNET_assert (listen_socket6 == cls);
522 t6 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
526 tc = GNUNET_SCHEDULER_get_task_context ();
527 if (0 == (GNUNET_SCHEDULER_REASON_READ_READY & tc->reason))
528 return; /* shutdown? */
529 size = GNUNET_NETWORK_socket_recvfrom_amount (listen_socket6);
533 return; /* read error!? */
539 addrlen = sizeof (v6);
540 sret = GNUNET_NETWORK_socket_recvfrom (listen_socket6,
543 (struct sockaddr *) &v6,
547 GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
551 GNUNET_break (size == sret);
552 handle_request (listen_socket6,
562 * Main function that will be run.
565 * @param args remaining command-line arguments
566 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
567 * @param c configuration
573 const struct GNUNET_CONFIGURATION_Handle *c)
581 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
582 _("No DNS server specified!\n"));
585 GNUNET_SCHEDULER_add_shutdown (&do_shutdown,
587 if (NULL == (gns = GNUNET_GNS_connect (cfg)))
589 GNUNET_assert (NULL != (dns_stub = GNUNET_DNSSTUB_start (128)));
591 GNUNET_DNSSTUB_add_dns_ip (dns_stub,
594 GNUNET_DNSSTUB_stop (dns_stub);
595 GNUNET_GNS_disconnect (gns);
599 listen_socket4 = GNUNET_NETWORK_socket_create (PF_INET,
602 if (NULL != listen_socket4)
604 struct sockaddr_in v4;
606 memset (&v4, 0, sizeof (v4));
607 v4.sin_family = AF_INET;
608 #if HAVE_SOCKADDR_IN_SIN_LEN
609 v4.sin_len = sizeof (v4);
611 v4.sin_port = htons (listen_port);
613 GNUNET_NETWORK_socket_bind (listen_socket4,
614 (struct sockaddr *) &v4,
617 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
618 GNUNET_NETWORK_socket_close (listen_socket4);
619 listen_socket4 = NULL;
622 listen_socket6 = GNUNET_NETWORK_socket_create (PF_INET6,
625 if (NULL != listen_socket6)
627 struct sockaddr_in6 v6;
629 memset (&v6, 0, sizeof (v6));
630 v6.sin6_family = AF_INET6;
631 #if HAVE_SOCKADDR_IN_SIN_LEN
632 v6.sin6_len = sizeof (v6);
634 v6.sin6_port = htons (listen_port);
636 GNUNET_NETWORK_socket_bind (listen_socket6,
637 (struct sockaddr *) &v6,
640 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
641 GNUNET_NETWORK_socket_close (listen_socket6);
642 listen_socket6 = NULL;
645 if ( (NULL == listen_socket4) &&
646 (NULL == listen_socket6) )
648 GNUNET_GNS_disconnect (gns);
650 GNUNET_DNSSTUB_stop (dns_stub);
654 if (NULL != listen_socket4)
655 t4 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
659 if (NULL != listen_socket6)
660 t6 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
668 * The main function for the dns2gns daemon.
670 * @param argc number of arguments from the command line
671 * @param argv command line arguments
672 * @return 0 ok, 1 on error
678 struct GNUNET_GETOPT_CommandLineOption options[] = {
679 GNUNET_GETOPT_option_string ('d',
682 gettext_noop ("IP of recursive DNS resolver to use (required)"),
684 GNUNET_GETOPT_option_uint ('p',
687 gettext_noop ("UDP port to listen on for inbound DNS requests; default: 2853"),
689 GNUNET_GETOPT_OPTION_END
694 GNUNET_STRINGS_get_utf8_args (argc, argv,
697 GNUNET_log_setup ("gnunet-dns2gns",
702 GNUNET_PROGRAM_run (argc, argv,
704 _("GNUnet DNS-to-GNS proxy (a DNS server)"),
706 &run, NULL)) ? 0 : 1;
707 GNUNET_free ((void*) argv);
711 /* end of gnunet-dns2gns.c */