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 1.1.2.44 2003/12/12 19:52:25 guus Exp $
25 #include <openssl/rand.h>
26 #include <openssl/err.h>
27 #include <openssl/evp.h>
28 #include <openssl/pem.h>
29 #include <openssl/hmac.h>
36 #include "connection.h"
52 EVP_CIPHER_CTX packet_ctx;
53 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
56 #define MAX_SEQNO 1073741824
58 static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level)
61 lzo_uint lzolen = MAXSIZE;
62 lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
64 } else if(level < 10) {
65 unsigned long destlen = MAXSIZE;
66 if(compress2(dest, &destlen, source, len, level) == Z_OK)
71 lzo_uint lzolen = MAXSIZE;
72 lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
79 static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level)
82 lzo_uint lzolen = MAXSIZE;
83 if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
88 unsigned long destlen = MAXSIZE;
89 if(uncompress(dest, &destlen, source, len) == Z_OK)
100 static void receive_packet(node_t *n, vpn_packet_t *packet)
104 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"),
105 packet->len, n->name, n->hostname);
110 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
112 vpn_packet_t pkt1, pkt2;
113 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
115 vpn_packet_t *outpkt = pkt[0];
117 char hmac[EVP_MAX_MD_SIZE];
122 /* Check packet length */
124 if(inpkt->len < sizeof(inpkt->seqno) + myself->maclength) {
125 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got too short packet from %s (%s)"),
126 n->name, n->hostname);
130 /* Check the message authentication code */
132 if(myself->digest && myself->maclength) {
133 inpkt->len -= myself->maclength;
134 HMAC(myself->digest, myself->key, myself->keylength,
135 (char *) &inpkt->seqno, inpkt->len, hmac, NULL);
137 if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, myself->maclength)) {
138 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"),
139 n->name, n->hostname);
144 /* Decrypt the packet */
147 outpkt = pkt[nextpkt++];
149 if(!EVP_DecryptInit_ex(&packet_ctx, NULL, NULL, NULL, NULL)
150 || !EVP_DecryptUpdate(&packet_ctx, (char *) &outpkt->seqno, &outlen,
151 (char *) &inpkt->seqno, inpkt->len)
152 || !EVP_DecryptFinal_ex(&packet_ctx, (char *) &outpkt->seqno + outlen, &outpad)) {
153 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Error decrypting packet from %s (%s): %s"),
154 n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
158 outpkt->len = outlen + outpad;
162 /* Check the sequence number */
164 inpkt->len -= sizeof(inpkt->seqno);
165 inpkt->seqno = ntohl(inpkt->seqno);
167 if(inpkt->seqno != n->received_seqno + 1) {
168 if(inpkt->seqno >= n->received_seqno + sizeof(n->late) * 8) {
169 logger(LOG_WARNING, _("Lost %d packets from %s (%s)"),
170 inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
172 memset(n->late, 0, sizeof(n->late));
173 } else if (inpkt->seqno <= n->received_seqno) {
174 if(inpkt->seqno <= n->received_seqno - sizeof(n->late) * 8 || !(n->late[(inpkt->seqno / 8) % sizeof(n->late)] & (1 << inpkt->seqno % 8))) {
175 logger(LOG_WARNING, _("Got late or replayed packet from %s (%s), seqno %d, last received %d"),
176 n->name, n->hostname, inpkt->seqno, n->received_seqno);
178 for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
179 n->late[(inpkt->seqno / 8) % sizeof(n->late)] |= 1 << i % 8;
183 n->received_seqno = inpkt->seqno;
184 n->late[(n->received_seqno / 8) % sizeof(n->late)] &= ~(1 << n->received_seqno % 8);
186 if(n->received_seqno > MAX_SEQNO)
189 /* Decompress the packet */
191 if(myself->compression) {
192 outpkt = pkt[nextpkt++];
194 if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, myself->compression)) < 0) {
195 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
196 n->name, n->hostname);
204 n->connection->last_ping_time = now;
206 receive_packet(n, inpkt);
209 void receive_tcppacket(connection_t *c, char *buffer, int len)
216 memcpy(outpkt.data, buffer, len);
218 receive_packet(c->node, &outpkt);
221 static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
223 vpn_packet_t pkt1, pkt2;
224 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
226 vpn_packet_t *outpkt;
230 static int priority = 0;
236 /* Make sure we have a valid key */
238 if(!n->status.validkey) {
239 ifdebug(TRAFFIC) logger(LOG_INFO,
240 _("No valid key known yet for %s (%s), queueing packet"),
241 n->name, n->hostname);
243 /* Since packet is on the stack of handle_tap_input(), we have to make a copy of it first. */
245 *(copy = xmalloc(sizeof(*copy))) = *inpkt;
247 list_insert_tail(n->queue, copy);
249 if(n->queue->count > MAXQUEUELENGTH)
250 list_delete_head(n->queue);
252 if(!n->status.waitingforkey)
253 send_req_key(n->nexthop->connection, myself, n);
255 n->status.waitingforkey = true;
260 origlen = inpkt->len;
261 origpriority = inpkt->priority;
263 /* Compress the packet */
266 outpkt = pkt[nextpkt++];
268 if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->compression)) < 0) {
269 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
270 n->name, n->hostname);
277 /* Add sequence number */
279 inpkt->seqno = htonl(++(n->sent_seqno));
280 inpkt->len += sizeof(inpkt->seqno);
282 /* Encrypt the packet */
285 outpkt = pkt[nextpkt++];
287 if(!EVP_EncryptInit_ex(&n->packet_ctx, NULL, NULL, NULL, NULL)
288 || !EVP_EncryptUpdate(&n->packet_ctx, (char *) &outpkt->seqno, &outlen,
289 (char *) &inpkt->seqno, inpkt->len)
290 || !EVP_EncryptFinal_ex(&n->packet_ctx, (char *) &outpkt->seqno + outlen, &outpad)) {
291 ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s): %s"),
292 n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
296 outpkt->len = outlen + outpad;
300 /* Add the message authentication code */
302 if(n->digest && n->maclength) {
303 HMAC(n->digest, n->key, n->keylength, (char *) &inpkt->seqno,
304 inpkt->len, (char *) &inpkt->seqno + inpkt->len, &outlen);
305 inpkt->len += n->maclength;
308 /* Determine which socket we have to use */
310 for(sock = 0; sock < listen_sockets; sock++)
311 if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
314 if(sock >= listen_sockets)
315 sock = 0; /* If none is available, just use the first and hope for the best. */
317 /* Send the packet */
319 #if defined(SOL_IP) && defined(IP_TOS)
320 if(priorityinheritance && origpriority != priority
321 && listen_socket[sock].sa.sa.sa_family == AF_INET) {
322 priority = origpriority;
323 ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
324 if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
325 logger(LOG_ERR, _("System call `%s' failed: %s"), "setsockopt", strerror(errno));
329 if((sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0) {
330 logger(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name, n->hostname, strerror(errno));
334 inpkt->len = origlen;
338 send a packet to the given vpn ip.
340 void send_packet(const node_t *n, vpn_packet_t *packet)
347 write_packet(packet);
351 ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
352 packet->len, n->name, n->hostname);
354 if(!n->status.reachable) {
355 ifdebug(TRAFFIC) logger(LOG_INFO, _("Node %s (%s) is not reachable"),
356 n->name, n->hostname);
360 via = (n->via == myself) ? n->nexthop : n->via;
363 ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet to %s via %s (%s)"),
364 n->name, via->name, n->via->hostname);
366 if((myself->options | via->options) & OPTION_TCPONLY) {
367 if(!send_tcppacket(via->connection, packet))
368 terminate_connection(via->connection, true);
370 send_udppacket(via, packet);
373 /* Broadcast a packet using the minimum spanning tree */
375 void broadcast_packet(const node_t *from, vpn_packet_t *packet)
382 ifdebug(TRAFFIC) logger(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
383 packet->len, from->name, from->hostname);
385 for(node = connection_tree->head; node; node = node->next) {
388 if(c->status.active && c->status.mst && c != from->nexthop->connection)
389 send_packet(c->node, packet);
393 void flush_queue(node_t *n)
395 list_node_t *node, *next;
399 ifdebug(TRAFFIC) logger(LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname);
401 for(node = n->queue->head; node; node = next) {
403 send_udppacket(n, node->data);
404 list_delete_node(n->queue, node);
408 void handle_incoming_vpn_data(int sock)
413 socklen_t fromlen = sizeof(from);
418 pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
421 logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
425 sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
427 n = lookup_node_udp(&from);
430 hostname = sockaddr2hostname(&from);
431 logger(LOG_WARNING, _("Received UDP packet from unknown source %s"),
437 receive_udppacket(n, &pkt);