2 net_packet.c -- Handles in- and outgoing VPN packets
3 Copyright (C) 1998-2005 Ivo Timmermans,
4 2000-2009 Guus Sliepen <guus@tinc-vpn.org>
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28 #include "splay_tree.h"
31 #include "connection.h"
48 #define EMSGSIZE WSAEMSGSIZE
52 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
54 static void send_udppacket(node_t *, vpn_packet_t *);
56 #define MAX_SEQNO 1073741824
58 static void send_mtu_probe_handler(int fd, short events, void *data) {
67 if(n->mtuprobes >= 10 && !n->minmtu) {
68 ifdebug(TRAFFIC) logger(LOG_INFO, _("No response to MTU probes from %s (%s)"), n->name, n->hostname);
72 for(i = 0; i < 3; i++) {
73 if(n->mtuprobes >= 30 || n->minmtu >= n->maxmtu) {
75 ifdebug(TRAFFIC) logger(LOG_INFO, _("Fixing MTU of %s (%s) to %d after %d probes"), n->name, n->hostname, n->mtu, n->mtuprobes);
79 len = n->minmtu + 1 + random() % (n->maxmtu - n->minmtu);
83 memset(packet.data, 0, 14);
84 randomize(packet.data + 14, len - 14);
88 ifdebug(TRAFFIC) logger(LOG_INFO, _("Sending MTU probe length %d to %s (%s)"), len, n->name, n->hostname);
90 send_udppacket(n, &packet);
93 event_add(&n->mtuevent, &(struct timeval){1, 0});
96 void send_mtu_probe(node_t *n) {
97 if(!timeout_initialized(&n->mtuevent))
98 timeout_set(&n->mtuevent, send_mtu_probe_handler, n);
99 send_mtu_probe_handler(0, 0, n);
102 void mtu_probe_h(node_t *n, vpn_packet_t *packet) {
103 ifdebug(TRAFFIC) logger(LOG_INFO, _("Got MTU probe length %d from %s (%s)"), packet->len, n->name, n->hostname);
105 if(!packet->data[0]) {
107 send_packet(n, packet);
109 if(n->minmtu < packet->len)
110 n->minmtu = packet->len;
114 static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
116 lzo_uint lzolen = MAXSIZE;
117 lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
119 } else if(level < 10) {
120 unsigned long destlen = MAXSIZE;
121 if(compress2(dest, &destlen, source, len, level) == Z_OK)
126 lzo_uint lzolen = MAXSIZE;
127 lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
134 static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
136 lzo_uint lzolen = MAXSIZE;
137 if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
142 unsigned long destlen = MAXSIZE;
143 if(uncompress(dest, &destlen, source, len) == Z_OK)
154 static void receive_packet(node_t *n, vpn_packet_t *packet) {
157 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"),
158 packet->len, n->name, n->hostname);
163 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
164 vpn_packet_t pkt1, pkt2;
165 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
167 vpn_packet_t *outpkt = pkt[0];
173 /* Check packet length */
175 if(inpkt->len < sizeof inpkt->seqno + digest_length(&myself->digest)) {
176 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got too short packet from %s (%s)"),
177 n->name, n->hostname);
181 /* Check the message authentication code */
183 if(digest_active(&myself->digest) && !digest_verify(&myself->digest, &inpkt->seqno, inpkt->len, &inpkt->seqno + inpkt->len)) {
184 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"), n->name, n->hostname);
188 /* Decrypt the packet */
190 if(cipher_active(&myself->cipher)) {
191 outpkt = pkt[nextpkt++];
194 if(!cipher_decrypt(&myself->cipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
195 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Error decrypting packet from %s (%s)"), n->name, n->hostname);
199 outpkt->len = outlen;
203 /* Check the sequence number */
205 inpkt->len -= sizeof inpkt->seqno;
206 inpkt->seqno = ntohl(inpkt->seqno);
208 if(inpkt->seqno != n->received_seqno + 1) {
209 if(inpkt->seqno >= n->received_seqno + sizeof n->late * 8) {
210 logger(LOG_WARNING, _("Lost %d packets from %s (%s)"),
211 inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
213 memset(n->late, 0, sizeof n->late);
214 } else if (inpkt->seqno <= n->received_seqno) {
215 if((n->received_seqno >= sizeof n->late * 8 && inpkt->seqno <= n->received_seqno - sizeof n->late * 8) || !(n->late[(inpkt->seqno / 8) % sizeof n->late] & (1 << inpkt->seqno % 8))) {
216 logger(LOG_WARNING, _("Got late or replayed packet from %s (%s), seqno %d, last received %d"),
217 n->name, n->hostname, inpkt->seqno, n->received_seqno);
221 for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
222 n->late[(i / 8) % sizeof n->late] |= 1 << i % 8;
226 n->late[(inpkt->seqno / 8) % sizeof n->late] &= ~(1 << inpkt->seqno % 8);
228 if(inpkt->seqno > n->received_seqno)
229 n->received_seqno = inpkt->seqno;
231 if(n->received_seqno > MAX_SEQNO)
234 /* Decompress the packet */
236 if(myself->compression) {
237 outpkt = pkt[nextpkt++];
239 if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, myself->compression)) < 0) {
240 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
241 n->name, n->hostname);
250 if(!inpkt->data[12] && !inpkt->data[13])
251 mtu_probe_h(n, inpkt);
253 receive_packet(n, inpkt);
256 void receive_tcppacket(connection_t *c, char *buffer, int len) {
262 if(c->options & OPTION_TCPONLY)
265 outpkt.priority = -1;
266 memcpy(outpkt.data, buffer, len);
268 receive_packet(c->node, &outpkt);
271 static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
272 vpn_packet_t pkt1, pkt2;
273 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
274 vpn_packet_t *inpkt = origpkt;
276 vpn_packet_t *outpkt;
279 static int priority = 0;
285 /* Make sure we have a valid key */
287 if(!n->status.validkey) {
288 ifdebug(TRAFFIC) logger(LOG_INFO,
289 _("No valid key known yet for %s (%s), forwarding via TCP"),
290 n->name, n->hostname);
292 if(!n->status.waitingforkey)
293 send_req_key(n->nexthop->connection, myself, n);
295 n->status.waitingforkey = true;
297 send_tcppacket(n->nexthop->connection, origpkt);
302 if(!n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
303 ifdebug(TRAFFIC) logger(LOG_INFO,
304 _("No minimum MTU established yet for %s (%s), forwarding via TCP"),
305 n->name, n->hostname);
307 send_tcppacket(n->nexthop->connection, origpkt);
310 origlen = inpkt->len;
311 origpriority = inpkt->priority;
313 /* Compress the packet */
316 outpkt = pkt[nextpkt++];
318 if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->compression)) < 0) {
319 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
320 n->name, n->hostname);
327 /* Add sequence number */
329 inpkt->seqno = htonl(++(n->sent_seqno));
330 inpkt->len += sizeof inpkt->seqno;
332 /* Encrypt the packet */
334 if(cipher_active(&n->cipher)) {
335 outpkt = pkt[nextpkt++];
338 if(!cipher_encrypt(&n->cipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
339 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s)"), n->name, n->hostname);
343 outpkt->len = outlen;
347 /* Add the message authentication code */
349 if(digest_active(&n->digest)) {
350 digest_create(&n->digest, &inpkt->seqno, inpkt->len, &inpkt->seqno + inpkt->len);
351 inpkt->len += digest_length(&n->digest);
354 /* Determine which socket we have to use */
356 for(sock = 0; sock < listen_sockets; sock++)
357 if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
360 if(sock >= listen_sockets)
361 sock = 0; /* If none is available, just use the first and hope for the best. */
363 /* Send the packet */
365 #if defined(SOL_IP) && defined(IP_TOS)
366 if(priorityinheritance && origpriority != priority
367 && listen_socket[sock].sa.sa.sa_family == AF_INET) {
368 priority = origpriority;
369 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
370 if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof priority)) /* SO_PRIORITY doesn't seem to work */
371 logger(LOG_ERR, _("System call `%s' failed: %s"), "setsockopt", strerror(errno));
375 if((sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0) {
376 if(errno == EMSGSIZE) {
377 if(n->maxmtu >= origlen)
378 n->maxmtu = origlen - 1;
379 if(n->mtu >= origlen)
380 n->mtu = origlen - 1;
382 logger(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name, n->hostname, strerror(errno));
386 origpkt->len = origlen;
390 send a packet to the given vpn ip.
392 void send_packet(const node_t *n, vpn_packet_t *packet) {
399 memcpy(packet->data, mymac.x, ETH_ALEN);
400 write_packet(packet);
404 ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
405 packet->len, n->name, n->hostname);
407 if(!n->status.reachable) {
408 ifdebug(TRAFFIC) logger(LOG_INFO, _("Node %s (%s) is not reachable"),
409 n->name, n->hostname);
413 via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via;
416 ifdebug(TRAFFIC) logger(LOG_INFO, _("Sending packet to %s via %s (%s)"),
417 n->name, via->name, n->via->hostname);
419 if(packet->priority == -1 || ((myself->options | via->options) & OPTION_TCPONLY)) {
420 if(!send_tcppacket(via->connection, packet))
421 terminate_connection(via->connection, true);
423 send_udppacket(via, packet);
426 /* Broadcast a packet using the minimum spanning tree */
428 void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
434 ifdebug(TRAFFIC) logger(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
435 packet->len, from->name, from->hostname);
438 send_packet(myself, packet);
440 for(node = connection_tree->head; node; node = node->next) {
443 if(c->status.active && c->status.mst && c != from->nexthop->connection)
444 send_packet(c->node, packet);
448 void handle_incoming_vpn_data(int sock, short events, void *data)
453 socklen_t fromlen = sizeof from;
458 pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
461 logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
465 sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
467 n = lookup_node_udp(&from);
470 hostname = sockaddr2hostname(&from);
471 logger(LOG_WARNING, _("Received UDP packet from unknown source %s"),
477 receive_udppacket(n, &pkt);
480 void handle_device_data(int sock, short events, void *data) {
483 if(read_packet(&packet))
484 route(myself, &packet);