2 net_packet.c -- Handles in- and outgoing VPN packets
3 Copyright (C) 1998-2005 Ivo Timmermans,
4 2000-2006 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);
87 ifdebug(TRAFFIC) logger(LOG_INFO, _("Sending MTU probe length %d to %s (%s)"), len, n->name, n->hostname);
89 send_udppacket(n, &packet);
92 event_add(&n->mtuevent, &(struct timeval){1, 0});
95 void send_mtu_probe(node_t *n) {
96 if(!timeout_initialized(&n->mtuevent))
97 timeout_set(&n->mtuevent, send_mtu_probe_handler, n);
98 send_mtu_probe_handler(0, 0, n);
101 void mtu_probe_h(node_t *n, vpn_packet_t *packet) {
102 ifdebug(TRAFFIC) logger(LOG_INFO, _("Got MTU probe length %d from %s (%s)"), packet->len, n->name, n->hostname);
104 if(!packet->data[0]) {
106 send_packet(n, packet);
108 if(n->minmtu < packet->len)
109 n->minmtu = packet->len;
113 static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
115 lzo_uint lzolen = MAXSIZE;
116 lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
118 } else if(level < 10) {
119 unsigned long destlen = MAXSIZE;
120 if(compress2(dest, &destlen, source, len, level) == Z_OK)
125 lzo_uint lzolen = MAXSIZE;
126 lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
133 static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
135 lzo_uint lzolen = MAXSIZE;
136 if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
141 unsigned long destlen = MAXSIZE;
142 if(uncompress(dest, &destlen, source, len) == Z_OK)
153 static void receive_packet(node_t *n, vpn_packet_t *packet) {
156 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"),
157 packet->len, n->name, n->hostname);
162 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
163 vpn_packet_t pkt1, pkt2;
164 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
166 vpn_packet_t *outpkt = pkt[0];
172 /* Check packet length */
174 if(inpkt->len < sizeof(inpkt->seqno) + digest_length(&myself->digest)) {
175 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got too short packet from %s (%s)"),
176 n->name, n->hostname);
180 /* Check the message authentication code */
182 if(digest_active(&myself->digest) && !digest_verify(&myself->digest, &inpkt->seqno, inpkt->len, &inpkt->seqno + inpkt->len)) {
183 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"), n->name, n->hostname);
187 /* Decrypt the packet */
189 if(cipher_active(&myself->cipher)) {
190 outpkt = pkt[nextpkt++];
193 if(!cipher_decrypt(&myself->cipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
194 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Error decrypting packet from %s (%s)"), n->name, n->hostname);
198 outpkt->len = outlen;
202 /* Check the sequence number */
204 inpkt->len -= sizeof(inpkt->seqno);
205 inpkt->seqno = ntohl(inpkt->seqno);
207 if(inpkt->seqno != n->received_seqno + 1) {
208 if(inpkt->seqno >= n->received_seqno + sizeof(n->late) * 8) {
209 logger(LOG_WARNING, _("Lost %d packets from %s (%s)"),
210 inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
212 memset(n->late, 0, sizeof(n->late));
213 } else if (inpkt->seqno <= n->received_seqno) {
214 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))) {
215 logger(LOG_WARNING, _("Got late or replayed packet from %s (%s), seqno %d, last received %d"),
216 n->name, n->hostname, inpkt->seqno, n->received_seqno);
220 for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
221 n->late[(i / 8) % sizeof(n->late)] |= 1 << i % 8;
225 n->late[(inpkt->seqno / 8) % sizeof(n->late)] &= ~(1 << inpkt->seqno % 8);
227 if(inpkt->seqno > n->received_seqno)
228 n->received_seqno = inpkt->seqno;
230 if(n->received_seqno > MAX_SEQNO)
233 /* Decompress the packet */
235 if(myself->compression) {
236 outpkt = pkt[nextpkt++];
238 if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, myself->compression)) < 0) {
239 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
240 n->name, n->hostname);
247 if(!inpkt->data[12] && !inpkt->data[13])
248 mtu_probe_h(n, inpkt);
250 receive_packet(n, inpkt);
253 void receive_tcppacket(connection_t *c, char *buffer, int len) {
259 memcpy(outpkt.data, buffer, len);
261 receive_packet(c->node, &outpkt);
264 static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
265 vpn_packet_t pkt1, pkt2;
266 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
267 vpn_packet_t *inpkt = origpkt;
269 vpn_packet_t *outpkt;
273 static int priority = 0;
279 /* Make sure we have a valid key */
281 if(!n->status.validkey) {
282 ifdebug(TRAFFIC) logger(LOG_INFO,
283 _("No valid key known yet for %s (%s), queueing packet"),
284 n->name, n->hostname);
286 /* Since packet is on the stack of handle_tap_input(), we have to make a copy of it first. */
288 *(copy = xmalloc(sizeof(*copy))) = *inpkt;
290 list_insert_tail(n->queue, copy);
292 if(n->queue->count > MAXQUEUELENGTH)
293 list_delete_head(n->queue);
295 if(!n->status.waitingforkey)
296 send_req_key(n->nexthop->connection, myself, n);
298 n->status.waitingforkey = true;
303 origlen = inpkt->len;
304 origpriority = inpkt->priority;
306 /* Compress the packet */
309 outpkt = pkt[nextpkt++];
311 if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->compression)) < 0) {
312 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
313 n->name, n->hostname);
320 /* Add sequence number */
322 inpkt->seqno = htonl(++(n->sent_seqno));
323 inpkt->len += sizeof(inpkt->seqno);
325 /* Encrypt the packet */
327 if(cipher_active(&n->cipher)) {
328 outpkt = pkt[nextpkt++];
331 if(!cipher_encrypt(&n->cipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
332 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s)"), n->name, n->hostname);
336 outpkt->len = outlen;
340 /* Add the message authentication code */
342 if(digest_active(&n->digest)) {
343 digest_create(&n->digest, &inpkt->seqno, inpkt->len, &inpkt->seqno + inpkt->len);
344 inpkt->len += digest_length(&n->digest);
347 /* Determine which socket we have to use */
349 for(sock = 0; sock < listen_sockets; sock++)
350 if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
353 if(sock >= listen_sockets)
354 sock = 0; /* If none is available, just use the first and hope for the best. */
356 /* Send the packet */
358 #if defined(SOL_IP) && defined(IP_TOS)
359 if(priorityinheritance && origpriority != priority
360 && listen_socket[sock].sa.sa.sa_family == AF_INET) {
361 priority = origpriority;
362 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
363 if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
364 logger(LOG_ERR, _("System call `%s' failed: %s"), "setsockopt", strerror(errno));
368 if((sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0) {
369 if(errno == EMSGSIZE) {
370 if(n->maxmtu >= origlen)
371 n->maxmtu = origlen - 1;
372 if(n->mtu >= origlen)
373 n->mtu = origlen - 1;
375 logger(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name, n->hostname, strerror(errno));
379 origpkt->len = origlen;
383 send a packet to the given vpn ip.
385 void send_packet(const node_t *n, vpn_packet_t *packet) {
392 memcpy(packet->data, mymac.x, ETH_ALEN);
393 write_packet(packet);
397 ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
398 packet->len, n->name, n->hostname);
400 if(!n->status.reachable) {
401 ifdebug(TRAFFIC) logger(LOG_INFO, _("Node %s (%s) is not reachable"),
402 n->name, n->hostname);
406 via = (n->via == myself) ? n->nexthop : n->via;
409 ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet to %s via %s (%s)"),
410 n->name, via->name, n->via->hostname);
412 if((myself->options | via->options) & OPTION_TCPONLY) {
413 if(!send_tcppacket(via->connection, packet))
414 terminate_connection(via->connection, true);
416 send_udppacket(via, packet);
419 /* Broadcast a packet using the minimum spanning tree */
421 void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
427 ifdebug(TRAFFIC) logger(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
428 packet->len, from->name, from->hostname);
431 send_packet(myself, packet);
433 for(node = connection_tree->head; node; node = node->next) {
436 if(c->status.active && c->status.mst && c != from->nexthop->connection)
437 send_packet(c->node, packet);
441 void flush_queue(node_t *n) {
442 list_node_t *node, *next;
446 ifdebug(TRAFFIC) logger(LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname);
448 for(node = n->queue->head; node; node = next) {
450 send_udppacket(n, node->data);
451 list_delete_node(n->queue, node);
455 void handle_incoming_vpn_data(int sock, short events, void *data) {
459 socklen_t fromlen = sizeof(from);
464 pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
467 logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
471 sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
473 n = lookup_node_udp(&from);
476 hostname = sockaddr2hostname(&from);
477 logger(LOG_WARNING, _("Received UDP packet from unknown source %s"),
483 receive_udppacket(n, &pkt);
486 void handle_device_data(int sock, short events, void *data) {
489 if(read_packet(&packet))
490 route(myself, &packet);