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"
44 * The UDP-Socket through which DNS-Resolves will be sent if they are not to be
45 * sent through gnunet. The port of this socket will not be hijacked.
47 static struct GNUNET_NETWORK_Handle *dnsout;
50 * The port bound to the socket dnsout
52 static unsigned short dnsoutport;
55 * A handle to the DHT-Service
57 static struct GNUNET_DHT_Handle *dht;
60 * The configuration to use
62 static const struct GNUNET_CONFIGURATION_Handle *cfg;
65 * A list of DNS-Responses that have to be sent to the requesting client
67 static struct answer_packet_list *head;
70 * The tail of the list of DNS-responses
72 static struct answer_packet_list *tail;
75 * A structure containing a mapping from network-byte-ordered DNS-id to
76 * some information needed to handle this query
78 * It currently allocates at least
79 * (1 + machine-width + 32 + 32 + 16 + machine-width + 8) * 65536 bit
80 * = 1.7 MiB on 64 bit.
81 * = 1.2 MiB on 32 bit.
85 struct GNUNET_SERVER_Client* client;
87 unsigned remote_ip:32;
88 unsigned local_port:16;
91 } query_states[65536];
94 * A struct used to give more than one value as
95 * closure to receive_dht
97 struct receive_dht_cls {
99 struct GNUNET_DHT_GetHandle* handle;
103 * Hijack all outgoing DNS-Traffic but for traffic leaving "our" port.
106 hijack(unsigned short port) {
109 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Hijacking, port is %d\n", port);
110 snprintf(port_s, 6, "%d", port);
111 GNUNET_OS_start_process(NULL,
113 "gnunet-helper-hijack-dns",
120 * Delete the hijacking-routes
123 unhijack(unsigned short port) {
126 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "unHijacking, port is %d\n", port);
127 snprintf(port_s, 6, "%d", port);
128 GNUNET_OS_start_process(NULL,
130 "gnunet-helper-hijack-dns",
138 * Send the DNS-Response to the client. Gets called via the notify_transmit_ready-
142 send_answer(void* cls, size_t size, void* buf) {
143 struct answer_packet_list* query = head;
144 size_t len = ntohs(query->pkt.hdr.size);
146 GNUNET_assert(len <= size);
148 memcpy(buf, &query->pkt.hdr, len);
150 GNUNET_CONTAINER_DLL_remove (head, tail, query);
154 /* When more data is to be sent, reschedule */
156 GNUNET_SERVER_notify_transmit_ready(cls,
157 ntohs(head->pkt.hdr.size),
158 GNUNET_TIME_UNIT_FOREVER_REL,
166 * Receive a block from the dht.
169 receive_dht(void *cls,
170 struct GNUNET_TIME_Absolute exp,
171 const GNUNET_HashCode *key,
172 const struct GNUNET_PeerIdentity *const *get_path,
173 const struct GNUNET_PeerIdentity *const *put_path,
174 enum GNUNET_BLOCK_Type type,
178 unsigned short id = ((struct receive_dht_cls*)cls)->id;
179 struct GNUNET_DHT_GetHandle* handle = ((struct receive_dht_cls*)cls)->handle;
182 GNUNET_assert(type == GNUNET_BLOCK_TYPE_DNS);
184 /* If no query with this id is pending, ignore the block */
185 if (query_states[id].valid != GNUNET_YES) return;
186 query_states[id].valid = GNUNET_NO;
188 const struct GNUNET_DNS_Record* rec = data;
189 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
190 "Got block of size %d, peer: %08x, desc: %08x\n",
192 *((unsigned int*)&rec->peer),
193 *((unsigned int*)&rec->service_descriptor));
195 size_t len = sizeof(struct answer_packet) - 1 \
196 + sizeof(struct dns_static) \
197 + query_states[id].namelen \
198 + sizeof(struct dns_query_line) \
199 + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
200 + sizeof(struct dns_record_line) - 1 \
201 + 16; /* To hold the IPv6-Address */
203 struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
204 memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
206 answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
207 answer->pkt.hdr.size = htons(len);
208 answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_SERVICE;
210 GNUNET_CRYPTO_hash(&rec->peer,
211 sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
214 memcpy(&answer->pkt.service_descriptor,
215 &rec->service_descriptor,
216 sizeof(GNUNET_HashCode));
217 memcpy(&answer->pkt.service_type,
219 sizeof(answer->pkt.service_type));
220 memcpy(&answer->pkt.ports, &rec->ports, sizeof(answer->pkt.ports));
222 answer->pkt.from = query_states[id].remote_ip;
224 answer->pkt.to = query_states[id].local_ip;
225 answer->pkt.dst_port = query_states[id].local_port;
227 struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
233 dpkt->s.qdcount = htons(1);
234 dpkt->s.ancount = htons(1);
236 memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
237 GNUNET_free(query_states[id].name);
240 struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
241 dque->type = htons(28); /* AAAA */
242 dque->class = htons(1); /* IN */
244 char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
245 memcpy(anname, (char[]){0xc0, 0x0c}, 2);
247 struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
248 drec_data->type = htons(28); /* AAAA */
249 drec_data->class = htons(1); /* IN */
250 drec_data->ttl = htonl(3600); /* FIXME: read from block */
251 drec_data->data_len = htons(16);
253 /* Calculate at which offset in the packet the IPv6-Address belongs, it is
254 * filled in by the daemon-vpn */
255 answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data)-(unsigned long)(&answer->pkt)));
257 GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
259 GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
261 GNUNET_TIME_UNIT_FOREVER_REL,
263 query_states[id].client);
265 GNUNET_DHT_get_stop(handle);
269 * This receives a GNUNET_MESSAGE_TYPE_REHIJACK and rehijacks the DNS
273 struct GNUNET_SERVER_Client *client,
274 const struct GNUNET_MessageHeader *message) {
275 unhijack(dnsoutport);
280 * This receives the dns-payload from the daemon-vpn and sends it on over the udp-socket
283 receive_query(void *cls,
284 struct GNUNET_SERVER_Client *client,
285 const struct GNUNET_MessageHeader *message) {
286 struct query_packet* pkt = (struct query_packet*)message;
287 struct dns_pkt* dns = (struct dns_pkt*)pkt->data;
288 struct dns_pkt_parsed* pdns = parse_dns_packet(dns);
290 query_states[dns->s.id].valid = GNUNET_YES;
291 query_states[dns->s.id].client = client;
292 query_states[dns->s.id].local_ip = pkt->orig_from;
293 query_states[dns->s.id].local_port = pkt->src_port;
294 query_states[dns->s.id].remote_ip = pkt->orig_to;
295 query_states[dns->s.id].namelen = strlen((char*)dns->data) + 1;
296 query_states[dns->s.id].name = GNUNET_malloc(query_states[dns->s.id].namelen);
297 memcpy(query_states[dns->s.id].name, dns->data, query_states[dns->s.id].namelen);
299 if (pdns->queries[0]->namelen > 9 &&
300 0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 9), ".gnunet.", 9))
302 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for .gnunet!\n");
304 GNUNET_CRYPTO_hash(pdns->queries[0]->name, pdns->queries[0]->namelen, &key);
306 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
307 "Getting with key %08x, len is %d\n",
308 *((unsigned int*)&key),
309 pdns->queries[0]->namelen);
311 struct receive_dht_cls* cls = GNUNET_malloc(sizeof(struct receive_dht_cls));
314 cls->handle = GNUNET_DHT_get_start(dht,
315 GNUNET_TIME_UNIT_MINUTES,
316 GNUNET_BLOCK_TYPE_DNS,
329 /* The query should be sent to the network */
331 struct sockaddr_in dest;
332 memset(&dest, 0, sizeof dest);
333 dest.sin_port = htons(53);
334 dest.sin_addr.s_addr = pkt->orig_to;
336 GNUNET_NETWORK_socket_sendto(dnsout,
338 ntohs(pkt->hdr.size) - sizeof(struct query_packet) + 1,
339 (struct sockaddr*) &dest,
343 free_parsed_dns_packet(pdns);
345 GNUNET_SERVER_receive_done(client, GNUNET_OK);
349 * Read a response-packet of the UDP-Socket
352 read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
353 unsigned char buf[65536];
354 struct dns_pkt* dns = (struct dns_pkt*)buf;
356 if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
359 struct sockaddr_in addr;
360 memset(&addr, 0, sizeof addr);
361 socklen_t addrlen = sizeof addr;
364 r = GNUNET_NETWORK_socket_recvfrom(dnsout,
367 (struct sockaddr*)&addr,
370 /* if (r < 0) FIXME */
372 if (query_states[dns->s.id].valid == GNUNET_YES) {
373 query_states[dns->s.id].valid = GNUNET_NO;
375 size_t len = sizeof(struct answer_packet) + r - 1; /* 1 for the unsigned char data[1]; */
376 struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
377 answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
378 answer->pkt.hdr.size = htons(len);
379 answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_IP;
380 answer->pkt.from = addr.sin_addr.s_addr;
381 answer->pkt.to = query_states[dns->s.id].local_ip;
382 answer->pkt.dst_port = query_states[dns->s.id].local_port;
383 memcpy(answer->pkt.data, buf, r);
385 GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
387 GNUNET_SERVER_notify_transmit_ready(query_states[dns->s.id].client,
389 GNUNET_TIME_UNIT_FOREVER_REL,
391 query_states[dns->s.id].client);
394 GNUNET_SCHEDULER_add_read_net(GNUNET_TIME_UNIT_FOREVER_REL,
402 * Task run during shutdown.
408 cleanup_task (void *cls,
409 const struct GNUNET_SCHEDULER_TaskContext *tc)
411 unhijack(dnsoutport);
412 GNUNET_DHT_disconnect(dht);
416 * Publish a DNS-record in the DHT. This is up to now just for testing.
419 publish_name (void *cls,
420 const struct GNUNET_SCHEDULER_TaskContext *tc) {
421 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
424 char* name = "philipptoelke.gnunet.";
425 size_t size = sizeof(struct GNUNET_DNS_Record);
426 struct GNUNET_DNS_Record data;
427 memset(&data, 0, size);
429 data.purpose.size = htonl(size - sizeof(struct GNUNET_CRYPTO_RsaSignature));
430 data.purpose.purpose = GNUNET_SIGNATURE_PURPOSE_DNS_RECORD;
432 GNUNET_CRYPTO_hash(name, strlen(name)+1, &data.service_descriptor);
435 if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename(cfg, "GNUNETD",
436 "HOSTKEY", &keyfile))
438 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "could not read keyfile-value\n");
439 if (keyfile != NULL) GNUNET_free(keyfile);
443 struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key = GNUNET_CRYPTO_rsa_key_create_from_file(keyfile);
444 GNUNET_free(keyfile);
446 GNUNET_CRYPTO_rsa_key_get_public(my_private_key, &data.peer);
448 data.expiration_time = GNUNET_TIME_relative_to_absolute(GNUNET_TIME_UNIT_HOURS);
451 if (GNUNET_OK != GNUNET_CRYPTO_rsa_sign(my_private_key,
455 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "could not sign DNS_Record\n");
458 GNUNET_CRYPTO_rsa_key_free(my_private_key);
460 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
461 "Putting with key %08x\n",
462 *((unsigned int*)&data.service_descriptor));
465 &data.service_descriptor,
467 GNUNET_BLOCK_TYPE_DNS,
470 GNUNET_TIME_relative_to_absolute(GNUNET_TIME_UNIT_HOURS),
471 GNUNET_TIME_UNIT_MINUTES,
475 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_HOURS,
482 * @param server the initialized server
483 * @param cfg configuration to use
487 struct GNUNET_SERVER_Handle *server,
488 const struct GNUNET_CONFIGURATION_Handle *cfg_)
490 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
491 /* callback, cls, type, size */
492 {&receive_query, NULL, GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS, 0},
493 {&rehijack, NULL, GNUNET_MESSAGE_TYPE_REHIJACK, sizeof(struct GNUNET_MessageHeader)},
500 for (i = 0; i < 65536; i++) {
501 query_states[i].valid = GNUNET_NO;
504 dht = GNUNET_DHT_connect(cfg, 1024);
506 struct sockaddr_in addr;
508 dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
511 memset(&addr, 0, sizeof(struct sockaddr_in));
513 int err = GNUNET_NETWORK_socket_bind (dnsout,
514 (struct sockaddr*)&addr,
515 sizeof(struct sockaddr_in));
517 if (err != GNUNET_YES) {
518 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "Could not bind a port, exiting\n");
522 /* Read the port we bound to */
523 socklen_t addrlen = sizeof(struct sockaddr_in);
524 err = getsockname(GNUNET_NETWORK_get_fd(dnsout),
525 (struct sockaddr*) &addr,
528 dnsoutport = htons(addr.sin_port);
530 hijack(htons(addr.sin_port));
532 GNUNET_SCHEDULER_add_now (publish_name, NULL);
534 GNUNET_SCHEDULER_add_read_net(GNUNET_TIME_UNIT_FOREVER_REL, dnsout, &read_response, NULL);
536 GNUNET_SERVER_add_handlers (server, handlers);
537 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
543 * The main function for the dns service.
545 * @param argc number of arguments from the command line
546 * @param argv command line arguments
547 * @return 0 ok, 1 on error
550 main (int argc, char *const *argv)
553 GNUNET_SERVICE_run (argc,
556 GNUNET_SERVICE_OPTION_NONE,
557 &run, NULL)) ? 0 : 1;