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(unsigned short port) {
113 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Hijacking, port is %d\n", port);
114 snprintf(port_s, 6, "%d", port);
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 * Receive a block from the dht.
173 receive_dht(void *cls,
174 struct GNUNET_TIME_Absolute exp,
175 const GNUNET_HashCode *key,
176 const struct GNUNET_PeerIdentity *const *get_path,
177 const struct GNUNET_PeerIdentity *const *put_path,
178 enum GNUNET_BLOCK_Type type,
182 unsigned short id = ((struct receive_dht_cls*)cls)->id;
183 struct GNUNET_DHT_GetHandle* handle = ((struct receive_dht_cls*)cls)->handle;
186 GNUNET_assert(type == GNUNET_BLOCK_TYPE_DNS);
188 /* If no query with this id is pending, ignore the block */
189 if (query_states[id].valid != GNUNET_YES) return;
190 query_states[id].valid = GNUNET_NO;
192 const struct GNUNET_DNS_Record* rec = data;
193 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
194 "Got block of size %d, peer: %08x, desc: %08x\n",
196 *((unsigned int*)&rec->peer),
197 *((unsigned int*)&rec->service_descriptor));
199 size_t len = sizeof(struct answer_packet) - 1 \
200 + sizeof(struct dns_static) \
201 + query_states[id].namelen \
202 + sizeof(struct dns_query_line) \
203 + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
204 + sizeof(struct dns_record_line) - 1 \
205 + 16; /* To hold the IPv6-Address */
207 struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
208 memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
210 answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
211 answer->pkt.hdr.size = htons(len);
212 answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_SERVICE;
214 GNUNET_CRYPTO_hash(&rec->peer,
215 sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
218 memcpy(&answer->pkt.service_descriptor,
219 &rec->service_descriptor,
220 sizeof(GNUNET_HashCode));
221 memcpy(&answer->pkt.service_type,
223 sizeof(answer->pkt.service_type));
224 memcpy(&answer->pkt.ports, &rec->ports, sizeof(answer->pkt.ports));
226 answer->pkt.from = query_states[id].remote_ip;
228 answer->pkt.to = query_states[id].local_ip;
229 answer->pkt.dst_port = query_states[id].local_port;
231 struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
237 dpkt->s.qdcount = htons(1);
238 dpkt->s.ancount = htons(1);
240 memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
241 GNUNET_free(query_states[id].name);
244 struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
245 dque->type = htons(28); /* AAAA */
246 dque->class = htons(1); /* IN */
248 char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
249 memcpy(anname, (char[]){0xc0, 0x0c}, 2);
251 struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
252 drec_data->type = htons(28); /* AAAA */
253 drec_data->class = htons(1); /* IN */
254 drec_data->ttl = htonl(3600); /* FIXME: read from block */
255 drec_data->data_len = htons(16);
257 /* Calculate at which offset in the packet the IPv6-Address belongs, it is
258 * filled in by the daemon-vpn */
259 answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data)-(unsigned long)(&answer->pkt)));
261 GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
263 GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
265 GNUNET_TIME_UNIT_FOREVER_REL,
267 query_states[id].client);
269 GNUNET_DHT_get_stop(handle);
273 * This receives a GNUNET_MESSAGE_TYPE_REHIJACK and rehijacks the DNS
277 struct GNUNET_SERVER_Client *client,
278 const struct GNUNET_MessageHeader *message) {
279 unhijack(dnsoutport);
284 * This receives the dns-payload from the daemon-vpn and sends it on over the udp-socket
287 receive_query(void *cls,
288 struct GNUNET_SERVER_Client *client,
289 const struct GNUNET_MessageHeader *message) {
290 struct query_packet* pkt = (struct query_packet*)message;
291 struct dns_pkt* dns = (struct dns_pkt*)pkt->data;
292 struct dns_pkt_parsed* pdns = parse_dns_packet(dns);
294 query_states[dns->s.id].valid = GNUNET_YES;
295 query_states[dns->s.id].client = client;
296 query_states[dns->s.id].local_ip = pkt->orig_from;
297 query_states[dns->s.id].local_port = pkt->src_port;
298 query_states[dns->s.id].remote_ip = pkt->orig_to;
299 query_states[dns->s.id].namelen = strlen((char*)dns->data) + 1;
300 query_states[dns->s.id].name = GNUNET_malloc(query_states[dns->s.id].namelen);
301 memcpy(query_states[dns->s.id].name, dns->data, query_states[dns->s.id].namelen);
303 if (pdns->queries[0]->namelen > 9 &&
304 0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 9), ".gnunet.", 9))
306 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for .gnunet!\n");
308 GNUNET_CRYPTO_hash(pdns->queries[0]->name, pdns->queries[0]->namelen, &key);
310 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
311 "Getting with key %08x, len is %d\n",
312 *((unsigned int*)&key),
313 pdns->queries[0]->namelen);
315 struct receive_dht_cls* cls = GNUNET_malloc(sizeof(struct receive_dht_cls));
318 cls->handle = GNUNET_DHT_get_start(dht,
319 GNUNET_TIME_UNIT_MINUTES,
320 GNUNET_BLOCK_TYPE_DNS,
333 /* The query should be sent to the network */
335 struct sockaddr_in dest;
336 memset(&dest, 0, sizeof dest);
337 dest.sin_port = htons(53);
338 dest.sin_addr.s_addr = pkt->orig_to;
340 GNUNET_NETWORK_socket_sendto(dnsout,
342 ntohs(pkt->hdr.size) - sizeof(struct query_packet) + 1,
343 (struct sockaddr*) &dest,
347 free_parsed_dns_packet(pdns);
349 GNUNET_SERVER_receive_done(client, GNUNET_OK);
353 * Read a response-packet of the UDP-Socket
356 read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
357 unsigned char buf[65536];
358 struct dns_pkt* dns = (struct dns_pkt*)buf;
360 if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
363 struct sockaddr_in addr;
364 memset(&addr, 0, sizeof addr);
365 unsigned int addrlen = sizeof addr;
368 r = GNUNET_NETWORK_socket_recvfrom(dnsout,
371 (struct sockaddr*)&addr,
374 /* if (r < 0) FIXME */
376 if (query_states[dns->s.id].valid == GNUNET_YES) {
377 query_states[dns->s.id].valid = GNUNET_NO;
379 size_t len = sizeof(struct answer_packet) + r - 1; /* 1 for the unsigned char data[1]; */
380 struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
381 answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
382 answer->pkt.hdr.size = htons(len);
383 answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_IP;
384 answer->pkt.from = addr.sin_addr.s_addr;
385 answer->pkt.to = query_states[dns->s.id].local_ip;
386 answer->pkt.dst_port = query_states[dns->s.id].local_port;
387 memcpy(answer->pkt.data, buf, r);
389 GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
391 GNUNET_SERVER_notify_transmit_ready(query_states[dns->s.id].client,
393 GNUNET_TIME_UNIT_FOREVER_REL,
395 query_states[dns->s.id].client);
398 GNUNET_SCHEDULER_add_read_net(sched,
399 GNUNET_TIME_UNIT_FOREVER_REL,
407 * Task run during shutdown.
413 cleanup_task (void *cls,
414 const struct GNUNET_SCHEDULER_TaskContext *tc)
416 unhijack(dnsoutport);
417 GNUNET_DHT_disconnect(dht);
421 * Publish a DNS-record in the DHT. This is up to now just for testing.
424 publish_name (void *cls,
425 const struct GNUNET_SCHEDULER_TaskContext *tc) {
426 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
429 char* name = "philipptoelke.gnunet.";
430 size_t size = sizeof(struct GNUNET_DNS_Record);
431 struct GNUNET_DNS_Record data;
432 memset(&data, 0, size);
434 data.purpose.size = htonl(size - sizeof(struct GNUNET_CRYPTO_RsaSignature));
435 data.purpose.purpose = GNUNET_SIGNATURE_PURPOSE_DNS_RECORD;
437 GNUNET_CRYPTO_hash(name, strlen(name)+1, &data.service_descriptor);
440 if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename(cfg, "GNUNETD",
441 "HOSTKEY", &keyfile))
443 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "could not read keyfile-value\n");
444 if (keyfile != NULL) GNUNET_free(keyfile);
448 struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key = GNUNET_CRYPTO_rsa_key_create_from_file(keyfile);
449 GNUNET_free(keyfile);
451 GNUNET_CRYPTO_rsa_key_get_public(my_private_key, &data.peer);
453 data.expiration_time = GNUNET_TIME_relative_to_absolute(GNUNET_TIME_UNIT_HOURS);
456 if (GNUNET_OK != GNUNET_CRYPTO_rsa_sign(my_private_key,
460 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "could not sign DNS_Record\n");
463 GNUNET_CRYPTO_rsa_key_free(my_private_key);
465 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
466 "Putting with key %08x\n",
467 *((unsigned int*)&data.service_descriptor));
470 &data.service_descriptor,
472 GNUNET_BLOCK_TYPE_DNS,
475 GNUNET_TIME_relative_to_absolute(GNUNET_TIME_UNIT_HOURS),
476 GNUNET_TIME_UNIT_MINUTES,
480 GNUNET_SCHEDULER_add_delayed (sched,
481 GNUNET_TIME_UNIT_HOURS,
488 * @param sched scheduler to use
489 * @param server the initialized server
490 * @param cfg configuration to use
494 struct GNUNET_SCHEDULER_Handle *sched_,
495 struct GNUNET_SERVER_Handle *server,
496 const struct GNUNET_CONFIGURATION_Handle *cfg_)
498 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
499 /* callback, cls, type, size */
500 {&receive_query, NULL, GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS, 0},
501 {&rehijack, NULL, GNUNET_MESSAGE_TYPE_REHIJACK, sizeof(struct GNUNET_MessageHeader)},
509 for (i = 0; i < 65536; i++) {
510 query_states[i].valid = GNUNET_NO;
513 dht = GNUNET_DHT_connect(sched, cfg, 1024);
515 struct sockaddr_in addr;
517 dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
520 memset(&addr, 0, sizeof(struct sockaddr_in));
522 int err = GNUNET_NETWORK_socket_bind (dnsout,
523 (struct sockaddr*)&addr,
524 sizeof(struct sockaddr_in));
526 if (err != GNUNET_YES) {
527 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "Could not bind a port, exiting\n");
531 /* Read the port we bound to */
532 socklen_t addrlen = sizeof(struct sockaddr_in);
533 err = getsockname(GNUNET_NETWORK_get_fd(dnsout),
534 (struct sockaddr*) &addr,
537 dnsoutport = htons(addr.sin_port);
539 hijack(htons(addr.sin_port));
541 GNUNET_SCHEDULER_add_now (sched, publish_name, NULL);
543 GNUNET_SCHEDULER_add_read_net(sched, GNUNET_TIME_UNIT_FOREVER_REL, dnsout, &read_response, NULL);
545 GNUNET_SERVER_add_handlers (server, handlers);
546 GNUNET_SCHEDULER_add_delayed (sched,
547 GNUNET_TIME_UNIT_FOREVER_REL,
553 * The main function for the dns service.
555 * @param argc number of arguments from the command line
556 * @param argv command line arguments
557 * @return 0 ok, 1 on error
560 main (int argc, char *const *argv)
563 GNUNET_SERVICE_run (argc,
566 GNUNET_SERVICE_OPTION_NONE,
567 &run, NULL)) ? 0 : 1;