2 net_packet.c -- Handles in- and outgoing VPN packets
3 Copyright (C) 1998-2002 Ivo Timmermans <ivo@o2w.nl>,
4 2000-2002 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 1.1.2.27 2003/04/18 21:18:36 guus Exp $
28 #include <netinet/in.h>
34 #include <sys/types.h>
37 #include <sys/ioctl.h>
38 /* SunOS really wants sys/socket.h BEFORE net/if.h,
39 and FreeBSD wants these lines below the rest. */
40 #include <arpa/inet.h>
41 #include <sys/socket.h>
43 #ifdef HAVE_NETINET_IN_SYSTM_H
44 #include <netinet/in_systm.h>
46 #ifdef HAVE_NETINET_IP_H
47 #include <netinet/ip.h>
49 #ifdef HAVE_NETINET_TCP_H
50 #include <netinet/tcp.h>
53 #include <openssl/rand.h>
54 #include <openssl/evp.h>
55 #include <openssl/pem.h>
56 #include <openssl/hmac.h>
66 #include "connection.h"
83 EVP_CIPHER_CTX packet_ctx;
85 #define MAX_SEQNO 1073741824
89 void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
91 vpn_packet_t pkt1, pkt2;
92 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
94 vpn_packet_t *outpkt = pkt[0];
96 long int complen = MTU + 12;
97 char hmac[EVP_MAX_MD_SIZE];
102 /* Check the message authentication code */
104 if(myself->digest && myself->maclength) {
105 inpkt->len -= myself->maclength;
106 HMAC(myself->digest, myself->key, myself->keylength,
107 (char *) &inpkt->seqno, inpkt->len, hmac, NULL);
109 if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, myself->maclength)) {
110 if(debug_lvl >= DEBUG_TRAFFIC)
111 syslog(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"),
112 n->name, n->hostname);
117 /* Decrypt the packet */
120 outpkt = pkt[nextpkt++];
122 EVP_DecryptInit_ex(&packet_ctx, myself->cipher, NULL, myself->key,
123 myself->key + myself->cipher->key_len);
124 EVP_DecryptUpdate(&packet_ctx, (char *) &outpkt->seqno, &outlen,
125 (char *) &inpkt->seqno, inpkt->len);
126 EVP_DecryptFinal_ex(&packet_ctx, (char *) &outpkt->seqno + outlen, &outpad);
128 outpkt->len = outlen + outpad;
132 /* Check the sequence number */
134 inpkt->len -= sizeof(inpkt->seqno);
135 inpkt->seqno = ntohl(inpkt->seqno);
137 if(inpkt->seqno != n->received_seqno + 1) {
138 if(inpkt->seqno >= n->received_seqno + sizeof(n->late) * 8) {
139 if(debug_lvl >= DEBUG_TRAFFIC)
140 syslog(LOG_WARNING, _("Lost %d packets from %s (%s)"),
141 inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
143 memset(n->late, 0, sizeof(n->late));
144 } else if (inpkt->seqno <= n->received_seqno) {
145 if(inpkt->seqno <= n->received_seqno - sizeof(n->late) * 8 || !(n->late[(inpkt->seqno / 8) % sizeof(n->late)] & (1 << inpkt->seqno % 8))) {
146 syslog(LOG_WARNING, _("Got late or replayed packet from %s (%s), seqno %d, last received %d"),
147 n->name, n->hostname, inpkt->seqno, n->received_seqno, n->late[(inpkt->seqno / 8) % sizeof(n->late)]);
149 for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
150 n->late[(inpkt->seqno / 8) % sizeof(n->late)] |= 1 << i % 8;
154 n->received_seqno = inpkt->seqno;
155 n->late[(n->received_seqno / 8) % sizeof(n->late)] &= ~(1 << n->received_seqno % 8);
157 if(n->received_seqno > MAX_SEQNO)
160 /* Decompress the packet */
162 if(myself->compression) {
163 outpkt = pkt[nextpkt++];
165 if(uncompress(outpkt->data, &complen, inpkt->data, inpkt->len) != Z_OK) {
166 syslog(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
167 n->name, n->hostname);
171 outpkt->len = complen;
175 receive_packet(n, inpkt);
178 void receive_tcppacket(connection_t *c, char *buffer, int len)
185 memcpy(outpkt.data, buffer, len);
187 receive_packet(c->node, &outpkt);
190 void receive_packet(node_t *n, vpn_packet_t *packet)
194 if(debug_lvl >= DEBUG_TRAFFIC)
195 syslog(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"),
196 packet->len, n->name, n->hostname);
198 route_incoming(n, packet);
201 void send_udppacket(node_t *n, vpn_packet_t *inpkt)
203 vpn_packet_t pkt1, pkt2;
204 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
206 vpn_packet_t *outpkt;
209 long int complen = MTU + 12;
211 static int priority = 0;
217 /* Make sure we have a valid key */
219 if(!n->status.validkey) {
220 if(debug_lvl >= DEBUG_TRAFFIC)
222 _("No valid key known yet for %s (%s), queueing packet"),
223 n->name, n->hostname);
225 /* Since packet is on the stack of handle_tap_input(), we have to make a copy of it first. */
227 copy = xmalloc(sizeof(vpn_packet_t));
228 memcpy(copy, inpkt, sizeof(vpn_packet_t));
230 list_insert_tail(n->queue, copy);
232 if(n->queue->count > MAXQUEUELENGTH)
233 list_delete_head(n->queue);
235 if(!n->status.waitingforkey)
236 send_req_key(n->nexthop->connection, myself, n);
238 n->status.waitingforkey = 1;
243 origlen = inpkt->len;
244 origpriority = inpkt->priority;
246 /* Compress the packet */
249 outpkt = pkt[nextpkt++];
252 (outpkt->data, &complen, inpkt->data, inpkt->len,
253 n->compression) != Z_OK) {
254 syslog(LOG_ERR, _("Error while compressing packet to %s (%s)"),
255 n->name, n->hostname);
259 outpkt->len = complen;
263 /* Add sequence number */
265 inpkt->seqno = htonl(++(n->sent_seqno));
266 inpkt->len += sizeof(inpkt->seqno);
268 /* Encrypt the packet */
271 outpkt = pkt[nextpkt++];
273 EVP_EncryptInit_ex(&packet_ctx, n->cipher, NULL, n->key, n->key + n->cipher->key_len);
274 EVP_EncryptUpdate(&packet_ctx, (char *) &outpkt->seqno, &outlen,
275 (char *) &inpkt->seqno, inpkt->len);
276 EVP_EncryptFinal_ex(&packet_ctx, (char *) &outpkt->seqno + outlen, &outpad);
278 outpkt->len = outlen + outpad;
282 /* Add the message authentication code */
284 if(n->digest && n->maclength) {
285 HMAC(n->digest, n->key, n->keylength, (char *) &inpkt->seqno,
286 inpkt->len, (char *) &inpkt->seqno + inpkt->len, &outlen);
287 inpkt->len += n->maclength;
290 /* Determine which socket we have to use */
292 for(sock = 0; sock < listen_sockets; sock++)
293 if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
296 if(sock >= listen_sockets)
297 sock = 0; /* If none is available, just use the first and hope for the best. */
299 /* Send the packet */
301 #if defined(SOL_IP) && defined(IP_TOS)
302 if(priorityinheritance && origpriority != priority
303 && listen_socket[sock].sa.sa.sa_family == AF_INET) {
304 priority = origpriority;
305 if(debug_lvl >= DEBUG_TRAFFIC)
306 syslog(LOG_DEBUG, _("Setting outgoing packet priority to %d"),
308 if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
309 syslog(LOG_ERR, _("System call `%s' failed: %s"), "setsockopt",
314 if((sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0) {
315 syslog(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name,
316 n->hostname, strerror(errno));
320 inpkt->len = origlen;
324 send a packet to the given vpn ip.
326 void send_packet(node_t *n, vpn_packet_t *packet)
332 if(debug_lvl >= DEBUG_TRAFFIC)
333 syslog(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
334 packet->len, n->name, n->hostname);
337 if(debug_lvl >= DEBUG_TRAFFIC)
338 syslog(LOG_NOTICE, _("Packet is looping back to us!"));
343 if(!n->status.reachable) {
344 if(debug_lvl >= DEBUG_TRAFFIC)
345 syslog(LOG_INFO, _("Node %s (%s) is not reachable"),
346 n->name, n->hostname);
351 via = (n->via == myself) ? n->nexthop : n->via;
353 if(via != n && debug_lvl >= DEBUG_TRAFFIC)
354 syslog(LOG_ERR, _("Sending packet to %s via %s (%s)"),
355 n->name, via->name, n->via->hostname);
357 if((myself->options | via->options) & OPTION_TCPONLY) {
358 if(send_tcppacket(via->connection, packet))
359 terminate_connection(via->connection, 1);
361 send_udppacket(via, packet);
364 /* Broadcast a packet using the minimum spanning tree */
366 void broadcast_packet(node_t *from, vpn_packet_t *packet)
373 if(debug_lvl >= DEBUG_TRAFFIC)
374 syslog(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
375 packet->len, from->name, from->hostname);
377 for(node = connection_tree->head; node; node = node->next) {
378 c = (connection_t *) node->data;
380 if(c->status.active && c->status.mst && c != from->nexthop->connection)
381 send_packet(c->node, packet);
385 void flush_queue(node_t *n)
387 list_node_t *node, *next;
391 if(debug_lvl >= DEBUG_TRAFFIC)
392 syslog(LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname);
394 for(node = n->queue->head; node; node = next) {
396 send_udppacket(n, (vpn_packet_t *) node->data);
397 list_delete_node(n->queue, node);
401 void handle_incoming_vpn_data(int sock)
404 int x, l = sizeof(x);
407 socklen_t fromlen = sizeof(from);
412 if(getsockopt(sock, SOL_SOCKET, SO_ERROR, &x, &l) < 0) {
413 syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%s"),
414 __FILE__, __LINE__, sock, strerror(errno));
420 syslog(LOG_ERR, _("Incoming data socket error: %s"), strerror(x));
424 pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
427 syslog(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
431 sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
433 n = lookup_node_udp(&from);
436 hostname = sockaddr2hostname(&from);
437 syslog(LOG_WARNING, _("Received UDP packet from unknown source %s"),
444 n->connection->last_ping_time = now;
446 receive_udppacket(n, &pkt);