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3 Copyright (C) 2012-2013 GNUnet e.V.
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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,
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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.
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16 along with this program. If not, see <http://www.gnu.org/licenses/>.
18 SPDX-License-Identifier: AGPL3.0-or-later
21 * @file gnunet-dns2gns.c
22 * @brief DNS server that translates DNS requests to GNS
23 * @author Christian Grothoff
26 #include <gnunet_util_lib.h>
27 #include <gnunet_dnsparser_lib.h>
28 #include <gnunet_gns_service.h>
29 #include <gnunet_dnsstub_lib.h>
33 * Timeout for DNS requests.
35 #define TIMEOUT GNUNET_TIME_UNIT_MINUTES
38 * Data kept per request.
43 * Socket to use for sending the reply.
45 struct GNUNET_NETWORK_Handle *lsock;
48 * Destination address to use.
53 * Initially, this is the DNS request, it will then be
54 * converted to the DNS response.
56 struct GNUNET_DNSPARSER_Packet *packet;
59 * Our GNS request handle.
61 struct GNUNET_GNS_LookupWithTldRequest *lookup;
64 * Our DNS request handle
66 struct GNUNET_DNSSTUB_RequestSocket *dns_lookup;
69 * Task run on timeout or shutdown to clean up without
72 struct GNUNET_SCHEDULER_Task *timeout_task;
75 * Original UDP request message.
80 * Number of bytes in @e addr.
85 * Number of bytes in @e udp_msg.
90 * ID of the original request.
92 uint16_t original_request_id;
96 * The address to bind to
98 static in_addr_t address;
101 * The IPv6 address to bind to
103 static struct in6_addr address6;
107 * Handle to GNS resolver.
109 struct GNUNET_GNS_Handle *gns;
114 struct GNUNET_DNSSTUB_Context *dns_stub;
117 * Listen socket for IPv4.
119 static struct GNUNET_NETWORK_Handle *listen_socket4;
122 * Listen socket for IPv6.
124 static struct GNUNET_NETWORK_Handle *listen_socket6;
127 * Task for IPv4 socket.
129 static struct GNUNET_SCHEDULER_Task *t4;
132 * Task for IPv6 socket.
134 static struct GNUNET_SCHEDULER_Task *t6;
142 * UDP Port we listen on for inbound DNS requests.
144 static unsigned int listen_port = 53;
147 * Configuration to use.
149 static const struct GNUNET_CONFIGURATION_Handle *cfg;
153 * Task run on shutdown. Cleans up everything.
158 do_shutdown (void *cls)
163 GNUNET_SCHEDULER_cancel (t4);
168 GNUNET_SCHEDULER_cancel (t6);
171 if (NULL != listen_socket4)
173 GNUNET_NETWORK_socket_close (listen_socket4);
174 listen_socket4 = NULL;
176 if (NULL != listen_socket6)
178 GNUNET_NETWORK_socket_close (listen_socket6);
179 listen_socket6 = NULL;
183 GNUNET_GNS_disconnect (gns);
186 if (NULL != dns_stub)
188 GNUNET_DNSSTUB_stop (dns_stub);
195 * Send the response for the given request and clean up.
197 * @param request context for the request.
200 send_response (struct Request *request)
207 GNUNET_DNSPARSER_pack (request->packet,
208 UINT16_MAX /* is this not too much? */,
212 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
213 _ ("Failed to pack DNS response into UDP packet!\n"));
217 sret = GNUNET_NETWORK_socket_sendto (request->lsock,
223 (size != (size_t) sret))
224 GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
228 GNUNET_SCHEDULER_cancel (request->timeout_task);
229 GNUNET_DNSPARSER_free_packet (request->packet);
230 GNUNET_free (request->udp_msg);
231 GNUNET_free (request);
236 * Task run on timeout. Cleans up request.
238 * @param cls `struct Request *` of the request to clean up
241 do_timeout (void *cls)
243 struct Request *request = cls;
245 if (NULL != request->packet)
246 GNUNET_DNSPARSER_free_packet (request->packet);
247 if (NULL != request->lookup)
248 GNUNET_GNS_lookup_with_tld_cancel (request->lookup);
249 if (NULL != request->dns_lookup)
250 GNUNET_DNSSTUB_resolve_cancel (request->dns_lookup);
251 GNUNET_free (request->udp_msg);
252 GNUNET_free (request);
257 * Iterator called on obtained result for a DNS lookup
260 * @param dns the DNS udp payload
261 * @param r size of the DNS payload
264 dns_result_processor (void *cls,
265 const struct GNUNET_TUN_DnsHeader *dns,
268 struct Request *request = cls;
272 /* DNSSTUB gave up, so we trigger timeout early */
273 GNUNET_SCHEDULER_cancel (request->timeout_task);
274 do_timeout (request);
277 if (request->original_request_id != dns->id)
279 /* for a another query, ignore */
282 request->packet = GNUNET_DNSPARSER_parse ((char *) dns,
284 GNUNET_DNSSTUB_resolve_cancel (request->dns_lookup);
285 send_response (request);
290 * Iterator called on obtained result for a GNS lookup.
293 * @param was_gns #GNUNET_NO if the TLD is not configured for GNS
294 * @param rd_count number of records in @a rd
295 * @param rd the records in reply
298 result_processor (void *cls,
301 const struct GNUNET_GNSRECORD_Data *rd)
303 struct Request *request = cls;
304 struct GNUNET_DNSPARSER_Packet *packet;
305 struct GNUNET_DNSPARSER_Record rec;
307 request->lookup = NULL;
308 if (GNUNET_NO == was_gns)
310 /* TLD not configured for GNS, fall back to DNS */
311 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
312 "Using DNS resolver IP `%s' to resolve `%s'\n",
314 request->packet->queries[0].name);
315 request->original_request_id = request->packet->id;
316 GNUNET_DNSPARSER_free_packet (request->packet);
317 request->packet = NULL;
318 request->dns_lookup = GNUNET_DNSSTUB_resolve (dns_stub,
320 request->udp_msg_size,
321 &dns_result_processor,
325 packet = request->packet;
326 packet->flags.query_or_response = 1;
327 packet->flags.return_code = GNUNET_TUN_DNS_RETURN_CODE_NO_ERROR;
328 packet->flags.checking_disabled = 0;
329 packet->flags.authenticated_data = 1;
330 packet->flags.zero = 0;
331 packet->flags.recursion_available = 1;
332 packet->flags.message_truncated = 0;
333 packet->flags.authoritative_answer = 0;
334 // packet->flags.opcode = GNUNET_TUN_DNS_OPCODE_STATUS; // ???
335 for (uint32_t i = 0; i < rd_count; i++)
337 // FIXME: do we need to hanlde #GNUNET_GNSRECORD_RF_SHADOW_RECORD
338 // here? Or should we do this in libgnunetgns?
339 rec.expiration_time.abs_value_us = rd[i].expiration_time;
340 switch (rd[i].record_type)
342 case GNUNET_DNSPARSER_TYPE_A:
343 GNUNET_assert (sizeof(struct in_addr) == rd[i].data_size);
344 rec.name = GNUNET_strdup (packet->queries[0].name);
345 rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
346 rec.type = GNUNET_DNSPARSER_TYPE_A;
347 rec.data.raw.data = GNUNET_new (struct in_addr);
348 GNUNET_memcpy (rec.data.raw.data,
351 rec.data.raw.data_len = sizeof(struct in_addr);
352 GNUNET_array_append (packet->answers,
357 case GNUNET_DNSPARSER_TYPE_AAAA:
358 GNUNET_assert (sizeof(struct in6_addr) == rd[i].data_size);
359 rec.name = GNUNET_strdup (packet->queries[0].name);
360 rec.data.raw.data = GNUNET_new (struct in6_addr);
361 rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
362 rec.type = GNUNET_DNSPARSER_TYPE_AAAA;
363 GNUNET_memcpy (rec.data.raw.data,
366 rec.data.raw.data_len = sizeof(struct in6_addr);
367 GNUNET_array_append (packet->answers,
372 case GNUNET_DNSPARSER_TYPE_CNAME:
373 rec.name = GNUNET_strdup (packet->queries[0].name);
374 rec.data.hostname = GNUNET_strdup (rd[i].data);
375 rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
376 rec.type = GNUNET_DNSPARSER_TYPE_CNAME;
377 GNUNET_memcpy (rec.data.hostname,
380 GNUNET_array_append (packet->answers,
390 send_response (request);
395 * Handle DNS request.
397 * @param lsock socket to use for sending the reply
398 * @param addr address to use for sending the reply
399 * @param addr_len number of bytes in @a addr
400 * @param udp_msg DNS request payload
401 * @param udp_msg_size number of bytes in @a udp_msg
404 handle_request (struct GNUNET_NETWORK_Handle *lsock,
410 struct Request *request;
411 struct GNUNET_DNSPARSER_Packet *packet;
413 packet = GNUNET_DNSPARSER_parse (udp_msg,
417 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
418 _ ("Cannot parse DNS request from %s\n"),
419 GNUNET_a2s (addr, addr_len));
422 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
423 "Received request for `%s' with flags %u, #answers %d, #auth %d, #additional %d\n",
424 packet->queries[0].name,
425 (unsigned int) packet->flags.query_or_response,
426 (int) packet->num_answers,
427 (int) packet->num_authority_records,
428 (int) packet->num_additional_records);
429 if ((0 != packet->flags.query_or_response) ||
430 (0 != packet->num_answers) ||
431 (0 != packet->num_authority_records))
433 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
434 _ ("Received malformed DNS request from %s\n"),
435 GNUNET_a2s (addr, addr_len));
436 GNUNET_DNSPARSER_free_packet (packet);
439 if ((1 != packet->num_queries))
441 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
442 _ ("Received unsupported DNS request from %s\n"),
445 GNUNET_DNSPARSER_free_packet (packet);
448 request = GNUNET_malloc (sizeof(struct Request) + addr_len);
449 request->lsock = lsock;
450 request->packet = packet;
451 request->addr = &request[1];
452 request->addr_len = addr_len;
453 GNUNET_memcpy (&request[1],
456 request->udp_msg_size = udp_msg_size;
457 request->udp_msg = GNUNET_memdup (udp_msg,
459 request->timeout_task = GNUNET_SCHEDULER_add_delayed (TIMEOUT,
462 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
463 "Calling GNS on `%s'\n",
464 packet->queries[0].name);
465 request->lookup = GNUNET_GNS_lookup_with_tld (gns,
466 packet->queries[0].name,
467 packet->queries[0].type,
468 GNUNET_GNS_LO_DEFAULT,
475 * Task to read IPv4 DNS packets.
477 * @param cls the 'listen_socket4'
480 read_dns4 (void *cls)
482 struct sockaddr_in v4;
485 const struct GNUNET_SCHEDULER_TaskContext *tc;
487 GNUNET_assert (listen_socket4 == cls);
488 t4 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
492 tc = GNUNET_SCHEDULER_get_task_context ();
493 if (0 == (GNUNET_SCHEDULER_REASON_READ_READY & tc->reason))
494 return; /* shutdown? */
495 size = GNUNET_NETWORK_socket_recvfrom_amount (listen_socket4);
499 return; /* read error!? */
505 addrlen = sizeof(v4);
506 sret = GNUNET_NETWORK_socket_recvfrom (listen_socket4,
509 (struct sockaddr *) &v4,
513 GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
517 GNUNET_break (size == sret);
518 handle_request (listen_socket4,
528 * Task to read IPv6 DNS packets.
530 * @param cls the 'listen_socket6'
533 read_dns6 (void *cls)
535 struct sockaddr_in6 v6;
538 const struct GNUNET_SCHEDULER_TaskContext *tc;
540 GNUNET_assert (listen_socket6 == cls);
541 t6 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
545 tc = GNUNET_SCHEDULER_get_task_context ();
546 if (0 == (GNUNET_SCHEDULER_REASON_READ_READY & tc->reason))
547 return; /* shutdown? */
548 size = GNUNET_NETWORK_socket_recvfrom_amount (listen_socket6);
552 return; /* read error!? */
558 addrlen = sizeof(v6);
559 sret = GNUNET_NETWORK_socket_recvfrom (listen_socket6,
562 (struct sockaddr *) &v6,
566 GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
570 GNUNET_break (size == sret);
571 handle_request (listen_socket6,
581 * Main function that will be run.
584 * @param args remaining command-line arguments
585 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
586 * @param c configuration
592 const struct GNUNET_CONFIGURATION_Handle *c)
602 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
603 _ ("No DNS server specified!\n"));
606 GNUNET_SCHEDULER_add_shutdown (&do_shutdown,
608 if (NULL == (gns = GNUNET_GNS_connect (cfg)))
610 GNUNET_assert (NULL != (dns_stub = GNUNET_DNSSTUB_start (128)));
612 GNUNET_DNSSTUB_add_dns_ip (dns_stub,
615 GNUNET_DNSSTUB_stop (dns_stub);
616 GNUNET_GNS_disconnect (gns);
621 /* Get address to bind to */
622 if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_string (c, "dns2gns",
626 // No address specified
627 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
628 "Don't know what to bind to...\n");
629 GNUNET_free (addr_str);
630 GNUNET_SCHEDULER_shutdown ();
633 if (1 != inet_pton (AF_INET, addr_str, &address))
635 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
636 "Unable to parse address %s\n",
638 GNUNET_free (addr_str);
639 GNUNET_SCHEDULER_shutdown ();
642 GNUNET_free (addr_str);
643 /* Get address to bind to */
644 if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_string (c, "dns2gns",
648 // No address specified
649 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
650 "Don't know what to bind6 to...\n");
651 GNUNET_free (addr_str);
652 GNUNET_SCHEDULER_shutdown ();
655 if (1 != inet_pton (AF_INET6, addr_str, &address6))
657 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
658 "Unable to parse IPv6 address %s\n",
660 GNUNET_free (addr_str);
661 GNUNET_SCHEDULER_shutdown ();
664 GNUNET_free (addr_str);
666 listen_socket4 = GNUNET_NETWORK_socket_create (PF_INET,
669 if (NULL != listen_socket4)
671 struct sockaddr_in v4;
673 memset (&v4, 0, sizeof(v4));
674 v4.sin_family = AF_INET;
675 v4.sin_addr.s_addr = address;
676 #if HAVE_SOCKADDR_IN_SIN_LEN
677 v4.sin_len = sizeof(v4);
679 v4.sin_port = htons (listen_port);
681 GNUNET_NETWORK_socket_bind (listen_socket4,
682 (struct sockaddr *) &v4,
685 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
686 GNUNET_NETWORK_socket_close (listen_socket4);
687 listen_socket4 = NULL;
690 listen_socket6 = GNUNET_NETWORK_socket_create (PF_INET6,
693 if (NULL != listen_socket6)
695 struct sockaddr_in6 v6;
697 memset (&v6, 0, sizeof(v6));
698 v6.sin6_family = AF_INET6;
699 v6.sin6_addr = address6;
700 #if HAVE_SOCKADDR_IN_SIN_LEN
701 v6.sin6_len = sizeof(v6);
703 v6.sin6_port = htons (listen_port);
705 GNUNET_NETWORK_socket_bind (listen_socket6,
706 (struct sockaddr *) &v6,
709 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
710 GNUNET_NETWORK_socket_close (listen_socket6);
711 listen_socket6 = NULL;
714 if ((NULL == listen_socket4) &&
715 (NULL == listen_socket6))
717 GNUNET_GNS_disconnect (gns);
719 GNUNET_DNSSTUB_stop (dns_stub);
723 if (NULL != listen_socket4)
724 t4 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
728 if (NULL != listen_socket6)
729 t6 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
737 * The main function for the dns2gns daemon.
739 * @param argc number of arguments from the command line
740 * @param argv command line arguments
741 * @return 0 ok, 1 on error
747 struct GNUNET_GETOPT_CommandLineOption options[] = {
748 GNUNET_GETOPT_option_string ('d',
752 "IP of recursive DNS resolver to use (required)"),
754 GNUNET_GETOPT_option_uint ('p',
758 "UDP port to listen on for inbound DNS requests; default: 2853"),
760 GNUNET_GETOPT_OPTION_END
765 GNUNET_STRINGS_get_utf8_args (argc, argv,
768 GNUNET_log_setup ("gnunet-dns2gns",
773 GNUNET_PROGRAM_run (argc, argv,
775 _ ("GNUnet DNS-to-GNS proxy (a DNS server)"),
777 &run, NULL)) ? 0 : 1;
778 GNUNET_free_nz ((void *) argv);
783 /* end of gnunet-dns2gns.c */