2 This file is part of GNUnet.
3 (C) 2009 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version.
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 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
22 * @file vpn/gnunet-service-dns.c
23 * @author Philipp Toelke
26 #include "gnunet_getopt_lib.h"
27 #include "gnunet_service_lib.h"
28 #include "gnunet_network_lib.h"
29 #include "gnunet_os_lib.h"
30 #include "gnunet-service-dns-p.h"
31 #include "gnunet_protocols.h"
32 #include "gnunet-vpn-packet.h"
33 #include "gnunet-vpn-pretty-print.h"
34 #include "gnunet_container_lib.h"
35 #include "gnunet-dns-parser.h"
36 #include "gnunet_dht_service.h"
37 #include "gnunet_block_lib.h"
38 #include "block_dns.h"
39 #include "gnunet_crypto_lib.h"
40 #include "gnunet_signatures.h"
43 * The scheduler to use throughout the service
45 static struct GNUNET_SCHEDULER_Handle *sched;
48 * The UDP-Socket through which DNS-Resolves will be sent if they are not to be
49 * sent through gnunet. The port of this socket will not be hijacked.
51 static struct GNUNET_NETWORK_Handle *dnsout;
54 * The port bound to the socket dnsout
56 static unsigned short dnsoutport;
59 * A handle to the DHT-Service
61 static struct GNUNET_DHT_Handle *dht;
64 * The configuration to use
66 static const struct GNUNET_CONFIGURATION_Handle *cfg;
69 * A list of DNS-Responses that have to be sent to the requesting client
71 static struct answer_packet_list *head;
74 * The tail of the list of DNS-responses
76 static struct answer_packet_list *tail;
79 * A structure containing a mapping from network-byte-ordered DNS-id to
80 * some information needed to handle this query
82 * It currently allocates at least
83 * (1 + machine-width + 32 + 32 + 16 + machine-width + 8) * 65536 bit
84 * = 1.7 MiB on 64 bit.
85 * = 1.2 MiB on 32 bit.
89 struct GNUNET_SERVER_Client* client;
91 unsigned remote_ip:32;
92 unsigned local_port:16;
95 } query_states[65536];
98 * A struct used to give more than one value as
99 * closure to receive_dht
101 struct receive_dht_cls {
103 struct GNUNET_DHT_GetHandle* handle;
107 * Hijack all outgoing DNS-Traffic but for traffic leaving "our" port.
110 hijack(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tc) {
113 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Hijacking, port is %d\n", dnsoutport);
114 snprintf(port_s, 6, "%d", dnsoutport);
115 GNUNET_OS_process_close (GNUNET_OS_start_process(NULL,
117 "gnunet-helper-hijack-dns",
124 * Delete the hijacking-routes
127 unhijack(unsigned short port) {
130 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "unHijacking, port is %d\n", port);
131 snprintf(port_s, 6, "%d", port);
132 GNUNET_OS_start_process(NULL,
134 "gnunet-helper-hijack-dns",
142 * Send the DNS-Response to the client. Gets called via the notify_transmit_ready-
146 send_answer(void* cls, size_t size, void* buf) {
147 struct answer_packet_list* query = head;
148 size_t len = ntohs(query->pkt.hdr.size);
150 GNUNET_assert(len <= size);
152 memcpy(buf, &query->pkt.hdr, len);
154 GNUNET_CONTAINER_DLL_remove (head, tail, query);
158 /* When more data is to be sent, reschedule */
160 GNUNET_SERVER_notify_transmit_ready(cls,
161 ntohs(head->pkt.hdr.size),
162 GNUNET_TIME_UNIT_FOREVER_REL,
170 send_rev_query(void * cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
171 struct dns_pkt_parsed* pdns = (struct dns_pkt_parsed*) cls;
173 unsigned short id = pdns->s.id;
175 if (query_states[id].valid != GNUNET_YES) return;
176 query_states[id].valid = GNUNET_NO;
178 GNUNET_assert(query_states[id].namelen == 74);
180 size_t len = sizeof(struct answer_packet) - 1 \
181 + sizeof(struct dns_static) \
182 + 74 /* this is the length of a reverse ipv6-lookup */ \
183 + sizeof(struct dns_query_line) \
184 + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
185 + sizeof(struct dns_record_line) - 1 \
186 - 2 /* We do not know the lenght of the answer yet*/ \
187 - 2 /* No idea why... */ ;
189 struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
190 memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
192 answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
193 answer->pkt.hdr.size = htons(len);
194 answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_REV;
196 answer->pkt.from = query_states[id].remote_ip;
198 answer->pkt.to = query_states[id].local_ip;
199 answer->pkt.dst_port = query_states[id].local_port;
201 struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
207 dpkt->s.qdcount = htons(1);
208 dpkt->s.ancount = htons(1);
210 memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
211 GNUNET_free(query_states[id].name);
213 struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
214 dque->type = htons(12); /* PTR */
215 dque->class = htons(1); /* IN */
217 char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
218 memcpy(anname, (char[]){0xc0, 0x0c}, 2);
220 struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
221 drec_data->type = htons(12); /* AAAA */
222 drec_data->class = htons(1); /* IN */
223 drec_data->ttl = htonl(3600); /* FIXME: read from block */
225 /* Calculate at which offset in the packet the length of the name and the
226 * name, it is filled in by the daemon-vpn */
227 answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data_len)-(unsigned long)(&answer->pkt)));
229 GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
231 GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
233 GNUNET_TIME_UNIT_FOREVER_REL,
235 query_states[id].client);
239 * complete dns-packet with empty name in the answer
240 * provide offsett of the name
245 * Receive a block from the dht.
248 receive_dht(void *cls,
249 struct GNUNET_TIME_Absolute exp,
250 const GNUNET_HashCode *key,
251 const struct GNUNET_PeerIdentity *const *get_path,
252 const struct GNUNET_PeerIdentity *const *put_path,
253 enum GNUNET_BLOCK_Type type,
257 unsigned short id = ((struct receive_dht_cls*)cls)->id;
258 struct GNUNET_DHT_GetHandle* handle = ((struct receive_dht_cls*)cls)->handle;
261 GNUNET_assert(type == GNUNET_BLOCK_TYPE_DNS);
263 /* If no query with this id is pending, ignore the block */
264 if (query_states[id].valid != GNUNET_YES) return;
265 query_states[id].valid = GNUNET_NO;
267 const struct GNUNET_DNS_Record* rec = data;
268 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
269 "Got block of size %d, peer: %08x, desc: %08x\n",
271 *((unsigned int*)&rec->peer),
272 *((unsigned int*)&rec->service_descriptor));
274 size_t len = sizeof(struct answer_packet) - 1 \
275 + sizeof(struct dns_static) \
276 + query_states[id].namelen \
277 + sizeof(struct dns_query_line) \
278 + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
279 + sizeof(struct dns_record_line) - 1 \
280 + 16; /* To hold the IPv6-Address */
282 struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
283 memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
285 answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
286 answer->pkt.hdr.size = htons(len);
287 answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_SERVICE;
289 GNUNET_CRYPTO_hash(&rec->peer,
290 sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
293 memcpy(&answer->pkt.service_descriptor,
294 &rec->service_descriptor,
295 sizeof(GNUNET_HashCode));
296 memcpy(&answer->pkt.service_type,
298 sizeof(answer->pkt.service_type));
299 memcpy(&answer->pkt.ports, &rec->ports, sizeof(answer->pkt.ports));
301 answer->pkt.from = query_states[id].remote_ip;
303 answer->pkt.to = query_states[id].local_ip;
304 answer->pkt.dst_port = query_states[id].local_port;
306 struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
312 dpkt->s.qdcount = htons(1);
313 dpkt->s.ancount = htons(1);
315 memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
316 GNUNET_free(query_states[id].name);
318 struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
319 dque->type = htons(28); /* AAAA */
320 dque->class = htons(1); /* IN */
322 char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
323 memcpy(anname, (char[]){0xc0, 0x0c}, 2);
325 struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
326 drec_data->type = htons(28); /* AAAA */
327 drec_data->class = htons(1); /* IN */
328 drec_data->ttl = htonl(3600); /* FIXME: read from block */
329 drec_data->data_len = htons(16);
331 /* Calculate at which offset in the packet the IPv6-Address belongs, it is
332 * filled in by the daemon-vpn */
333 answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data)-(unsigned long)(&answer->pkt)));
335 GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
337 GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
339 GNUNET_TIME_UNIT_FOREVER_REL,
341 query_states[id].client);
343 GNUNET_DHT_get_stop(handle);
347 * This receives a GNUNET_MESSAGE_TYPE_REHIJACK and rehijacks the DNS
351 struct GNUNET_SERVER_Client *client,
352 const struct GNUNET_MessageHeader *message) {
353 unhijack(dnsoutport);
354 GNUNET_SCHEDULER_add_delayed(sched, GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
356 GNUNET_SERVER_receive_done(client, GNUNET_OK);
360 * This receives the dns-payload from the daemon-vpn and sends it on over the udp-socket
363 receive_query(void *cls,
364 struct GNUNET_SERVER_Client *client,
365 const struct GNUNET_MessageHeader *message) {
366 struct query_packet* pkt = (struct query_packet*)message;
367 struct dns_pkt* dns = (struct dns_pkt*)pkt->data;
368 struct dns_pkt_parsed* pdns = parse_dns_packet(dns);
370 query_states[dns->s.id].valid = GNUNET_YES;
371 query_states[dns->s.id].client = client;
372 query_states[dns->s.id].local_ip = pkt->orig_from;
373 query_states[dns->s.id].local_port = pkt->src_port;
374 query_states[dns->s.id].remote_ip = pkt->orig_to;
375 query_states[dns->s.id].namelen = strlen((char*)dns->data) + 1;
376 query_states[dns->s.id].name = GNUNET_malloc(query_states[dns->s.id].namelen);
377 memcpy(query_states[dns->s.id].name, dns->data, query_states[dns->s.id].namelen);
379 /* The query is for a .gnunet-address */
380 if (pdns->queries[0]->namelen > 9 &&
381 0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 9), ".gnunet.", 9))
383 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for .gnunet!\n");
385 GNUNET_CRYPTO_hash(pdns->queries[0]->name, pdns->queries[0]->namelen, &key);
387 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
388 "Getting with key %08x, len is %d\n",
389 *((unsigned int*)&key),
390 pdns->queries[0]->namelen);
392 struct receive_dht_cls* cls = GNUNET_malloc(sizeof(struct receive_dht_cls));
395 cls->handle = GNUNET_DHT_get_start(dht,
396 GNUNET_TIME_UNIT_MINUTES,
397 GNUNET_BLOCK_TYPE_DNS,
410 /* The query is for a PTR of a previosly resolved virtual IP */
411 if (htons(pdns->queries[0]->qtype) == 12 &&
412 pdns->queries[0]->namelen > 19 &&
413 0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 19), ".4.3.2.1.ip6.arpa.", 19))
415 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Reverse-Query for .gnunet!\n");
417 GNUNET_SCHEDULER_add_now(sched, send_rev_query, pdns);
422 /* The query should be sent to the network */
424 struct sockaddr_in dest;
425 memset(&dest, 0, sizeof dest);
426 dest.sin_port = htons(53);
427 dest.sin_addr.s_addr = pkt->orig_to;
429 GNUNET_NETWORK_socket_sendto(dnsout,
431 ntohs(pkt->hdr.size) - sizeof(struct query_packet) + 1,
432 (struct sockaddr*) &dest,
436 free_parsed_dns_packet(pdns);
439 GNUNET_SERVER_receive_done(client, GNUNET_OK);
443 * Read a response-packet of the UDP-Socket
446 read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
447 unsigned char buf[65536];
448 struct dns_pkt* dns = (struct dns_pkt*)buf;
450 if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
453 struct sockaddr_in addr;
454 memset(&addr, 0, sizeof addr);
455 unsigned int addrlen = sizeof addr;
458 r = GNUNET_NETWORK_socket_recvfrom(dnsout,
461 (struct sockaddr*)&addr,
464 /* if (r < 0) FIXME */
466 if (query_states[dns->s.id].valid == GNUNET_YES) {
467 query_states[dns->s.id].valid = GNUNET_NO;
469 size_t len = sizeof(struct answer_packet) + r - 1; /* 1 for the unsigned char data[1]; */
470 struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
471 answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
472 answer->pkt.hdr.size = htons(len);
473 answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_IP;
474 answer->pkt.from = addr.sin_addr.s_addr;
475 answer->pkt.to = query_states[dns->s.id].local_ip;
476 answer->pkt.dst_port = query_states[dns->s.id].local_port;
477 memcpy(answer->pkt.data, buf, r);
479 GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
481 GNUNET_SERVER_notify_transmit_ready(query_states[dns->s.id].client,
483 GNUNET_TIME_UNIT_FOREVER_REL,
485 query_states[dns->s.id].client);
488 GNUNET_SCHEDULER_add_read_net(sched,
489 GNUNET_TIME_UNIT_FOREVER_REL,
497 * Task run during shutdown.
503 cleanup_task (void *cls,
504 const struct GNUNET_SCHEDULER_TaskContext *tc)
506 unhijack(dnsoutport);
507 GNUNET_DHT_disconnect(dht);
511 * Publish a DNS-record in the DHT. This is up to now just for testing.
514 publish_name (void *cls,
515 const struct GNUNET_SCHEDULER_TaskContext *tc) {
516 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
519 char* name = "philipptoelke.gnunet.";
520 size_t size = sizeof(struct GNUNET_DNS_Record);
521 struct GNUNET_DNS_Record data;
522 memset(&data, 0, size);
524 data.purpose.size = htonl(size - sizeof(struct GNUNET_CRYPTO_RsaSignature));
525 data.purpose.purpose = GNUNET_SIGNATURE_PURPOSE_DNS_RECORD;
527 GNUNET_CRYPTO_hash(name, strlen(name)+1, &data.service_descriptor);
530 if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename(cfg, "GNUNETD",
531 "HOSTKEY", &keyfile))
533 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "could not read keyfile-value\n");
534 if (keyfile != NULL) GNUNET_free(keyfile);
538 struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key = GNUNET_CRYPTO_rsa_key_create_from_file(keyfile);
539 GNUNET_free(keyfile);
541 GNUNET_CRYPTO_rsa_key_get_public(my_private_key, &data.peer);
543 data.expiration_time = GNUNET_TIME_relative_to_absolute(GNUNET_TIME_UNIT_HOURS);
546 if (GNUNET_OK != GNUNET_CRYPTO_rsa_sign(my_private_key,
550 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "could not sign DNS_Record\n");
553 GNUNET_CRYPTO_rsa_key_free(my_private_key);
555 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
556 "Putting with key %08x\n",
557 *((unsigned int*)&data.service_descriptor));
560 &data.service_descriptor,
562 GNUNET_BLOCK_TYPE_DNS,
565 GNUNET_TIME_relative_to_absolute(GNUNET_TIME_UNIT_HOURS),
566 GNUNET_TIME_UNIT_MINUTES,
570 GNUNET_SCHEDULER_add_delayed (sched,
571 GNUNET_TIME_UNIT_HOURS,
578 * @param sched scheduler to use
579 * @param server the initialized server
580 * @param cfg configuration to use
584 struct GNUNET_SCHEDULER_Handle *sched_,
585 struct GNUNET_SERVER_Handle *server,
586 const struct GNUNET_CONFIGURATION_Handle *cfg_)
588 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
589 /* callback, cls, type, size */
590 {&receive_query, NULL, GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS, 0},
591 {&rehijack, NULL, GNUNET_MESSAGE_TYPE_REHIJACK, sizeof(struct GNUNET_MessageHeader)},
599 for (i = 0; i < 65536; i++) {
600 query_states[i].valid = GNUNET_NO;
603 dht = GNUNET_DHT_connect(sched, cfg, 1024);
605 struct sockaddr_in addr;
607 dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
610 memset(&addr, 0, sizeof(struct sockaddr_in));
612 int err = GNUNET_NETWORK_socket_bind (dnsout,
613 (struct sockaddr*)&addr,
614 sizeof(struct sockaddr_in));
616 if (err != GNUNET_YES) {
617 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "Could not bind a port, exiting\n");
621 /* Read the port we bound to */
622 socklen_t addrlen = sizeof(struct sockaddr_in);
623 err = getsockname(GNUNET_NETWORK_get_fd(dnsout),
624 (struct sockaddr*) &addr,
627 dnsoutport = htons(addr.sin_port);
629 GNUNET_SCHEDULER_add_now (sched, publish_name, NULL);
631 GNUNET_SCHEDULER_add_read_net(sched, GNUNET_TIME_UNIT_FOREVER_REL, dnsout, &read_response, NULL);
633 GNUNET_SERVER_add_handlers (server, handlers);
634 GNUNET_SCHEDULER_add_delayed (sched,
635 GNUNET_TIME_UNIT_FOREVER_REL,
641 * The main function for the dns service.
643 * @param argc number of arguments from the command line
644 * @param argv command line arguments
645 * @return 0 ok, 1 on error
648 main (int argc, char *const *argv)
651 GNUNET_SERVICE_run (argc,
654 GNUNET_SERVICE_OPTION_NONE,
655 &run, NULL)) ? 0 : 1;