2 net_packet.c -- Handles in- and outgoing VPN packets
3 Copyright (C) 1998-2003 Ivo Timmermans <ivo@o2w.nl>,
4 2000-2003 Guus Sliepen <guus@sliepen.eu.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.
20 $Id: net_packet.c,v 1.1.2.42 2003/10/10 16:24:24 guus Exp $
25 #include <openssl/rand.h>
26 #include <openssl/evp.h>
27 #include <openssl/pem.h>
28 #include <openssl/hmac.h>
35 #include "connection.h"
51 EVP_CIPHER_CTX packet_ctx;
52 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
55 #define MAX_SEQNO 1073741824
57 static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level)
60 lzo_uint lzolen = MAXSIZE;
61 lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
63 } else if(level < 10) {
64 unsigned long destlen = MAXSIZE;
65 if(compress2(dest, &destlen, source, len, level) == Z_OK)
70 lzo_uint lzolen = MAXSIZE;
71 lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
78 static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level)
81 lzo_uint lzolen = MAXSIZE;
82 if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
87 unsigned long destlen = MAXSIZE;
88 if(uncompress(dest, &destlen, source, len) == Z_OK)
99 static void receive_packet(node_t *n, vpn_packet_t *packet)
103 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"),
104 packet->len, n->name, n->hostname);
106 route_incoming(n, packet);
109 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
111 vpn_packet_t pkt1, pkt2;
112 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
114 vpn_packet_t *outpkt = pkt[0];
116 char hmac[EVP_MAX_MD_SIZE];
121 /* Check packet length */
123 if(inpkt->len < sizeof(inpkt->seqno) + myself->maclength) {
124 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got too short packet from %s (%s)"),
125 n->name, n->hostname);
129 /* Check the message authentication code */
131 if(myself->digest && myself->maclength) {
132 inpkt->len -= myself->maclength;
133 HMAC(myself->digest, myself->key, myself->keylength,
134 (char *) &inpkt->seqno, inpkt->len, hmac, NULL);
136 if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, myself->maclength)) {
137 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"),
138 n->name, n->hostname);
143 /* Decrypt the packet */
146 outpkt = pkt[nextpkt++];
148 EVP_DecryptInit_ex(&packet_ctx, NULL, NULL, NULL, NULL);
149 if(!EVP_DecryptUpdate(&packet_ctx, (char *) &outpkt->seqno, &outlen,
150 (char *) &inpkt->seqno, inpkt->len)) {
151 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Error decrypting packet from %s (%s): %s"),
152 n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
155 if(!EVP_DecryptFinal_ex(&packet_ctx, (char *) &outpkt->seqno + outlen, &outpad)) {
156 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Error decrypting packet from %s (%s): %s"),
157 n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
161 outpkt->len = outlen + outpad;
165 /* Check the sequence number */
167 inpkt->len -= sizeof(inpkt->seqno);
168 inpkt->seqno = ntohl(inpkt->seqno);
170 if(inpkt->seqno != n->received_seqno + 1) {
171 if(inpkt->seqno >= n->received_seqno + sizeof(n->late) * 8) {
172 logger(LOG_WARNING, _("Lost %d packets from %s (%s)"),
173 inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
175 memset(n->late, 0, sizeof(n->late));
176 } else if (inpkt->seqno <= n->received_seqno) {
177 if(inpkt->seqno <= n->received_seqno - sizeof(n->late) * 8 || !(n->late[(inpkt->seqno / 8) % sizeof(n->late)] & (1 << inpkt->seqno % 8))) {
178 logger(LOG_WARNING, _("Got late or replayed packet from %s (%s), seqno %d, last received %d"),
179 n->name, n->hostname, inpkt->seqno, n->received_seqno);
181 for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
182 n->late[(inpkt->seqno / 8) % sizeof(n->late)] |= 1 << i % 8;
186 n->received_seqno = inpkt->seqno;
187 n->late[(n->received_seqno / 8) % sizeof(n->late)] &= ~(1 << n->received_seqno % 8);
189 if(n->received_seqno > MAX_SEQNO)
192 /* Decompress the packet */
194 if(myself->compression) {
195 outpkt = pkt[nextpkt++];
197 if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, myself->compression)) < 0) {
198 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
199 n->name, n->hostname);
207 n->connection->last_ping_time = now;
209 receive_packet(n, inpkt);
212 void receive_tcppacket(connection_t *c, char *buffer, int len)
219 memcpy(outpkt.data, buffer, len);
221 receive_packet(c->node, &outpkt);
224 static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
226 vpn_packet_t pkt1, pkt2;
227 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
229 vpn_packet_t *outpkt;
233 static int priority = 0;
239 /* Make sure we have a valid key */
241 if(!n->status.validkey) {
242 ifdebug(TRAFFIC) logger(LOG_INFO,
243 _("No valid key known yet for %s (%s), queueing packet"),
244 n->name, n->hostname);
246 /* Since packet is on the stack of handle_tap_input(), we have to make a copy of it first. */
248 copy = xmalloc(sizeof(vpn_packet_t));
249 memcpy(copy, inpkt, sizeof(vpn_packet_t));
251 list_insert_tail(n->queue, copy);
253 if(n->queue->count > MAXQUEUELENGTH)
254 list_delete_head(n->queue);
256 if(!n->status.waitingforkey)
257 send_req_key(n->nexthop->connection, myself, n);
259 n->status.waitingforkey = true;
264 origlen = inpkt->len;
265 origpriority = inpkt->priority;
267 /* Compress the packet */
270 outpkt = pkt[nextpkt++];
272 if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->compression)) < 0) {
273 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
274 n->name, n->hostname);
281 /* Add sequence number */
283 inpkt->seqno = htonl(++(n->sent_seqno));
284 inpkt->len += sizeof(inpkt->seqno);
286 /* Encrypt the packet */
289 outpkt = pkt[nextpkt++];
291 EVP_EncryptInit_ex(&n->packet_ctx, NULL, NULL, NULL, NULL);
292 if(!EVP_EncryptUpdate(&n->packet_ctx, (char *) &outpkt->seqno, &outlen,
293 (char *) &inpkt->seqno, inpkt->len)) {
294 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s): %s"),
295 n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
298 if(!EVP_EncryptFinal_ex(&n->packet_ctx, (char *) &outpkt->seqno + outlen, &outpad)) {
299 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s): %s"),
300 n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
304 outpkt->len = outlen + outpad;
308 /* Add the message authentication code */
310 if(n->digest && n->maclength) {
311 HMAC(n->digest, n->key, n->keylength, (char *) &inpkt->seqno,
312 inpkt->len, (char *) &inpkt->seqno + inpkt->len, &outlen);
313 inpkt->len += n->maclength;
316 /* Determine which socket we have to use */
318 for(sock = 0; sock < listen_sockets; sock++)
319 if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
322 if(sock >= listen_sockets)
323 sock = 0; /* If none is available, just use the first and hope for the best. */
325 /* Send the packet */
327 #if defined(SOL_IP) && defined(IP_TOS)
328 if(priorityinheritance && origpriority != priority
329 && listen_socket[sock].sa.sa.sa_family == AF_INET) {
330 priority = origpriority;
331 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
332 if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
333 logger(LOG_ERR, _("System call `%s' failed: %s"), "setsockopt", strerror(errno));
337 if((sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0) {
338 logger(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name, n->hostname, strerror(errno));
342 inpkt->len = origlen;
346 send a packet to the given vpn ip.
348 void send_packet(const node_t *n, vpn_packet_t *packet)
354 ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
355 packet->len, n->name, n->hostname);
358 ifdebug(TRAFFIC) logger(LOG_NOTICE, _("Packet is looping back to us!"));
362 if(!n->status.reachable) {
363 ifdebug(TRAFFIC) logger(LOG_INFO, _("Node %s (%s) is not reachable"),
364 n->name, n->hostname);
368 via = (n->via == myself) ? n->nexthop : n->via;
371 ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet to %s via %s (%s)"),
372 n->name, via->name, n->via->hostname);
374 if((myself->options | via->options) & OPTION_TCPONLY) {
375 if(!send_tcppacket(via->connection, packet))
376 terminate_connection(via->connection, true);
378 send_udppacket(via, packet);
381 /* Broadcast a packet using the minimum spanning tree */
383 void broadcast_packet(const node_t *from, vpn_packet_t *packet)
390 ifdebug(TRAFFIC) logger(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
391 packet->len, from->name, from->hostname);
393 for(node = connection_tree->head; node; node = node->next) {
396 if(c->status.active && c->status.mst && c != from->nexthop->connection)
397 send_packet(c->node, packet);
401 void flush_queue(node_t *n)
403 list_node_t *node, *next;
407 ifdebug(TRAFFIC) logger(LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname);
409 for(node = n->queue->head; node; node = next) {
411 send_udppacket(n, node->data);
412 list_delete_node(n->queue, node);
416 void handle_incoming_vpn_data(int sock)
421 socklen_t fromlen = sizeof(from);
426 pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
429 logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
433 sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
435 n = lookup_node_udp(&from);
438 hostname = sockaddr2hostname(&from);
439 logger(LOG_WARNING, _("Received UDP packet from unknown source %s"),
445 receive_udppacket(n, &pkt);