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 UDP-Socket through which DNS-Resolves will be sent if they are not to be
44 * sent through gnunet. The port of this socket will not be hijacked.
46 static struct GNUNET_NETWORK_Handle *dnsout;
49 * The port bound to the socket dnsout
51 static unsigned short dnsoutport;
54 * A handle to the DHT-Service
56 static struct GNUNET_DHT_Handle *dht;
59 * The configuration to use
61 static const struct GNUNET_CONFIGURATION_Handle *cfg;
64 * A list of DNS-Responses that have to be sent to the requesting client
66 static struct answer_packet_list *head;
69 * The tail of the list of DNS-responses
71 static struct answer_packet_list *tail;
74 * A structure containing a mapping from network-byte-ordered DNS-id to
75 * some information needed to handle this query
77 * It currently allocates at least
78 * (1 + machine-width + 32 + 32 + 16 + machine-width + 8) * 65536 bit
79 * = 1.7 MiB on 64 bit.
80 * = 1.2 MiB on 32 bit.
84 struct GNUNET_SERVER_Client* client;
86 unsigned remote_ip:32;
87 unsigned local_port:16;
90 } query_states[65536];
93 * A struct used to give more than one value as
94 * closure to receive_dht
96 struct receive_dht_cls {
98 struct GNUNET_DHT_GetHandle* handle;
102 * Hijack all outgoing DNS-Traffic but for traffic leaving "our" port.
105 hijack(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tc) {
108 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Hijacking, port is %d\n", dnsoutport);
109 snprintf(port_s, 6, "%d", dnsoutport);
110 GNUNET_OS_process_close (GNUNET_OS_start_process(NULL,
112 "gnunet-helper-hijack-dns",
119 * Delete the hijacking-routes
122 unhijack(unsigned short port) {
125 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "unHijacking, port is %d\n", port);
126 snprintf(port_s, 6, "%d", port);
127 GNUNET_OS_start_process(NULL,
129 "gnunet-helper-hijack-dns",
137 * Send the DNS-Response to the client. Gets called via the notify_transmit_ready-
141 send_answer(void* cls, size_t size, void* buf) {
142 struct answer_packet_list* query = head;
143 size_t len = ntohs(query->pkt.hdr.size);
145 GNUNET_assert(len <= size);
147 memcpy(buf, &query->pkt.hdr, len);
149 GNUNET_CONTAINER_DLL_remove (head, tail, query);
153 /* When more data is to be sent, reschedule */
155 GNUNET_SERVER_notify_transmit_ready(cls,
156 ntohs(head->pkt.hdr.size),
157 GNUNET_TIME_UNIT_FOREVER_REL,
165 send_rev_query(void * cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
166 struct dns_pkt_parsed* pdns = (struct dns_pkt_parsed*) cls;
168 unsigned short id = pdns->s.id;
170 if (query_states[id].valid != GNUNET_YES) return;
171 query_states[id].valid = GNUNET_NO;
173 GNUNET_assert(query_states[id].namelen == 74);
175 size_t len = sizeof(struct answer_packet) - 1 \
176 + sizeof(struct dns_static) \
177 + 74 /* this is the length of a reverse ipv6-lookup */ \
178 + sizeof(struct dns_query_line) \
179 + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
180 + sizeof(struct dns_record_line) - 1 \
181 - 2 /* We do not know the lenght of the answer yet*/ \
182 - 2 /* No idea why... */ ;
184 struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
185 memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
187 answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
188 answer->pkt.hdr.size = htons(len);
189 answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_REV;
191 answer->pkt.from = query_states[id].remote_ip;
193 answer->pkt.to = query_states[id].local_ip;
194 answer->pkt.dst_port = query_states[id].local_port;
196 struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
202 dpkt->s.qdcount = htons(1);
203 dpkt->s.ancount = htons(1);
205 memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
206 GNUNET_free(query_states[id].name);
208 struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
209 dque->type = htons(12); /* PTR */
210 dque->class = htons(1); /* IN */
212 char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
213 memcpy(anname, (char[]){0xc0, 0x0c}, 2);
215 struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
216 drec_data->type = htons(12); /* AAAA */
217 drec_data->class = htons(1); /* IN */
218 drec_data->ttl = htonl(3600); /* FIXME: read from block */
220 /* Calculate at which offset in the packet the length of the name and the
221 * name, it is filled in by the daemon-vpn */
222 answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data_len)-(unsigned long)(&answer->pkt)));
224 GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
226 GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
228 GNUNET_TIME_UNIT_FOREVER_REL,
230 query_states[id].client);
234 * complete dns-packet with empty name in the answer
235 * provide offsett of the name
240 * Receive a block from the dht.
243 receive_dht(void *cls,
244 struct GNUNET_TIME_Absolute exp,
245 const GNUNET_HashCode *key,
246 const struct GNUNET_PeerIdentity *const *get_path,
247 const struct GNUNET_PeerIdentity *const *put_path,
248 enum GNUNET_BLOCK_Type type,
252 unsigned short id = ((struct receive_dht_cls*)cls)->id;
253 struct GNUNET_DHT_GetHandle* handle = ((struct receive_dht_cls*)cls)->handle;
256 GNUNET_assert(type == GNUNET_BLOCK_TYPE_DNS);
258 /* If no query with this id is pending, ignore the block */
259 if (query_states[id].valid != GNUNET_YES) return;
260 query_states[id].valid = GNUNET_NO;
262 const struct GNUNET_DNS_Record* rec = data;
263 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
264 "Got block of size %d, peer: %08x, desc: %08x\n",
266 *((unsigned int*)&rec->peer),
267 *((unsigned int*)&rec->service_descriptor));
269 size_t len = sizeof(struct answer_packet) - 1 \
270 + sizeof(struct dns_static) \
271 + query_states[id].namelen \
272 + sizeof(struct dns_query_line) \
273 + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
274 + sizeof(struct dns_record_line) - 1 \
275 + 16; /* To hold the IPv6-Address */
277 struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
278 memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
280 answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
281 answer->pkt.hdr.size = htons(len);
282 answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_SERVICE;
284 GNUNET_CRYPTO_hash(&rec->peer,
285 sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
288 memcpy(&answer->pkt.service_descriptor,
289 &rec->service_descriptor,
290 sizeof(GNUNET_HashCode));
291 memcpy(&answer->pkt.service_type,
293 sizeof(answer->pkt.service_type));
294 memcpy(&answer->pkt.ports, &rec->ports, sizeof(answer->pkt.ports));
296 answer->pkt.from = query_states[id].remote_ip;
298 answer->pkt.to = query_states[id].local_ip;
299 answer->pkt.dst_port = query_states[id].local_port;
301 struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
307 dpkt->s.qdcount = htons(1);
308 dpkt->s.ancount = htons(1);
310 memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
311 GNUNET_free(query_states[id].name);
313 struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
314 dque->type = htons(28); /* AAAA */
315 dque->class = htons(1); /* IN */
317 char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
318 memcpy(anname, (char[]){0xc0, 0x0c}, 2);
320 struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
321 drec_data->type = htons(28); /* AAAA */
322 drec_data->class = htons(1); /* IN */
323 drec_data->ttl = htonl(3600); /* FIXME: read from block */
324 drec_data->data_len = htons(16);
326 /* Calculate at which offset in the packet the IPv6-Address belongs, it is
327 * filled in by the daemon-vpn */
328 answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data)-(unsigned long)(&answer->pkt)));
330 GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
332 GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
334 GNUNET_TIME_UNIT_FOREVER_REL,
336 query_states[id].client);
338 GNUNET_DHT_get_stop(handle);
342 * This receives a GNUNET_MESSAGE_TYPE_REHIJACK and rehijacks the DNS
346 struct GNUNET_SERVER_Client *client,
347 const struct GNUNET_MessageHeader *message) {
348 unhijack(dnsoutport);
349 GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
351 GNUNET_SERVER_receive_done(client, GNUNET_OK);
355 * This receives the dns-payload from the daemon-vpn and sends it on over the udp-socket
358 receive_query(void *cls,
359 struct GNUNET_SERVER_Client *client,
360 const struct GNUNET_MessageHeader *message) {
361 struct query_packet* pkt = (struct query_packet*)message;
362 struct dns_pkt* dns = (struct dns_pkt*)pkt->data;
363 struct dns_pkt_parsed* pdns = parse_dns_packet(dns);
365 query_states[dns->s.id].valid = GNUNET_YES;
366 query_states[dns->s.id].client = client;
367 query_states[dns->s.id].local_ip = pkt->orig_from;
368 query_states[dns->s.id].local_port = pkt->src_port;
369 query_states[dns->s.id].remote_ip = pkt->orig_to;
370 query_states[dns->s.id].namelen = strlen((char*)dns->data) + 1;
371 query_states[dns->s.id].name = GNUNET_malloc(query_states[dns->s.id].namelen);
372 memcpy(query_states[dns->s.id].name, dns->data, query_states[dns->s.id].namelen);
374 /* The query is for a .gnunet-address */
375 if (pdns->queries[0]->namelen > 9 &&
376 0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 9), ".gnunet.", 9))
378 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for .gnunet!\n");
380 GNUNET_CRYPTO_hash(pdns->queries[0]->name, pdns->queries[0]->namelen, &key);
382 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
383 "Getting with key %08x, len is %d\n",
384 *((unsigned int*)&key),
385 pdns->queries[0]->namelen);
387 struct receive_dht_cls* cls = GNUNET_malloc(sizeof(struct receive_dht_cls));
390 cls->handle = GNUNET_DHT_get_start(dht,
391 GNUNET_TIME_UNIT_MINUTES,
392 GNUNET_BLOCK_TYPE_DNS,
394 DEFAULT_GET_REPLICATION,
406 /* The query is for a PTR of a previosly resolved virtual IP */
407 if (htons(pdns->queries[0]->qtype) == 12 &&
408 pdns->queries[0]->namelen > 19 &&
409 0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 19), ".4.3.2.1.ip6.arpa.", 19))
411 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Reverse-Query for .gnunet!\n");
413 GNUNET_SCHEDULER_add_now(send_rev_query, pdns);
418 /* The query should be sent to the network */
420 struct sockaddr_in dest;
421 memset(&dest, 0, sizeof dest);
422 dest.sin_port = htons(53);
423 dest.sin_addr.s_addr = pkt->orig_to;
425 GNUNET_NETWORK_socket_sendto(dnsout,
427 ntohs(pkt->hdr.size) - sizeof(struct query_packet) + 1,
428 (struct sockaddr*) &dest,
432 free_parsed_dns_packet(pdns);
435 GNUNET_SERVER_receive_done(client, GNUNET_OK);
439 * Read a response-packet of the UDP-Socket
442 read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
443 unsigned char buf[65536];
444 struct dns_pkt* dns = (struct dns_pkt*)buf;
446 if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
449 struct sockaddr_in addr;
450 memset(&addr, 0, sizeof addr);
451 socklen_t addrlen = sizeof addr;
454 r = GNUNET_NETWORK_socket_recvfrom(dnsout,
457 (struct sockaddr*)&addr,
460 /* if (r < 0) FIXME */
462 if (query_states[dns->s.id].valid == GNUNET_YES) {
463 query_states[dns->s.id].valid = GNUNET_NO;
465 size_t len = sizeof(struct answer_packet) + r - 1; /* 1 for the unsigned char data[1]; */
466 struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
467 answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
468 answer->pkt.hdr.size = htons(len);
469 answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_IP;
470 answer->pkt.from = addr.sin_addr.s_addr;
471 answer->pkt.to = query_states[dns->s.id].local_ip;
472 answer->pkt.dst_port = query_states[dns->s.id].local_port;
473 memcpy(answer->pkt.data, buf, r);
475 GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
477 GNUNET_SERVER_notify_transmit_ready(query_states[dns->s.id].client,
479 GNUNET_TIME_UNIT_FOREVER_REL,
481 query_states[dns->s.id].client);
484 GNUNET_SCHEDULER_add_read_net(GNUNET_TIME_UNIT_FOREVER_REL,
492 * Task run during shutdown.
498 cleanup_task (void *cls,
499 const struct GNUNET_SCHEDULER_TaskContext *tc)
501 unhijack(dnsoutport);
502 GNUNET_DHT_disconnect(dht);
506 * Publish a DNS-record in the DHT. This is up to now just for testing.
509 publish_name (void *cls,
510 const struct GNUNET_SCHEDULER_TaskContext *tc) {
511 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
514 char* name = "philipptoelke.gnunet.";
515 size_t size = sizeof(struct GNUNET_DNS_Record);
516 struct GNUNET_DNS_Record data;
517 memset(&data, 0, size);
519 data.purpose.size = htonl(size - sizeof(struct GNUNET_CRYPTO_RsaSignature));
520 data.purpose.purpose = GNUNET_SIGNATURE_PURPOSE_DNS_RECORD;
522 GNUNET_CRYPTO_hash(name, strlen(name)+1, &data.service_descriptor);
525 if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename(cfg, "GNUNETD",
526 "HOSTKEY", &keyfile))
528 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "could not read keyfile-value\n");
529 if (keyfile != NULL) GNUNET_free(keyfile);
533 struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key = GNUNET_CRYPTO_rsa_key_create_from_file(keyfile);
534 GNUNET_free(keyfile);
536 GNUNET_CRYPTO_rsa_key_get_public(my_private_key, &data.peer);
538 data.expiration_time = GNUNET_TIME_relative_to_absolute(GNUNET_TIME_UNIT_HOURS);
541 if (GNUNET_OK != GNUNET_CRYPTO_rsa_sign(my_private_key,
545 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "could not sign DNS_Record\n");
548 GNUNET_CRYPTO_rsa_key_free(my_private_key);
550 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
551 "Putting with key %08x\n",
552 *((unsigned int*)&data.service_descriptor));
555 &data.service_descriptor,
556 DEFAULT_PUT_REPLICATION,
558 GNUNET_BLOCK_TYPE_DNS,
561 GNUNET_TIME_relative_to_absolute(GNUNET_TIME_UNIT_HOURS),
562 GNUNET_TIME_UNIT_MINUTES,
566 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_HOURS,
573 * @param sched scheduler to use
574 * @param server the initialized server
575 * @param cfg configuration to use
579 struct GNUNET_SERVER_Handle *server,
580 const struct GNUNET_CONFIGURATION_Handle *cfg_)
582 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
583 /* callback, cls, type, size */
584 {&receive_query, NULL, GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS, 0},
585 {&rehijack, NULL, GNUNET_MESSAGE_TYPE_REHIJACK, sizeof(struct GNUNET_MessageHeader)},
592 for (i = 0; i < 65536; i++) {
593 query_states[i].valid = GNUNET_NO;
596 dht = GNUNET_DHT_connect(cfg, 1024);
598 struct sockaddr_in addr;
600 dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
603 memset(&addr, 0, sizeof(struct sockaddr_in));
605 int err = GNUNET_NETWORK_socket_bind (dnsout,
606 (struct sockaddr*)&addr,
607 sizeof(struct sockaddr_in));
609 if (err != GNUNET_YES) {
610 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "Could not bind a port, exiting\n");
614 /* Read the port we bound to */
615 socklen_t addrlen = sizeof(struct sockaddr_in);
616 err = getsockname(GNUNET_NETWORK_get_fd(dnsout),
617 (struct sockaddr*) &addr,
620 dnsoutport = htons(addr.sin_port);
622 GNUNET_SCHEDULER_add_now (publish_name, NULL);
624 GNUNET_SCHEDULER_add_read_net(GNUNET_TIME_UNIT_FOREVER_REL, dnsout, &read_response, NULL);
626 GNUNET_SERVER_add_handlers (server, handlers);
627 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
633 * The main function for the dns service.
635 * @param argc number of arguments from the command line
636 * @param argv command line arguments
637 * @return 0 ok, 1 on error
640 main (int argc, char *const *argv)
643 GNUNET_SERVICE_run (argc,
646 GNUNET_SERVICE_OPTION_NONE,
647 &run, NULL)) ? 0 : 1;