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 1.1.2.17 2002/06/21 10:11:12 guus Exp $
28 #include <netinet/in.h>
29 #ifdef HAVE_NETINET_IN_SYSTM_H
30 #include <netinet/in_systm.h>
32 #ifdef HAVE_NETINET_IP_H
33 #include <netinet/ip.h>
35 #ifdef HAVE_NETINET_TCP_H
36 #include <netinet/tcp.h>
43 #include <sys/types.h>
46 #include <sys/ioctl.h>
47 /* SunOS really wants sys/socket.h BEFORE net/if.h,
48 and FreeBSD wants these lines below the rest. */
49 #include <arpa/inet.h>
50 #include <sys/socket.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"
84 #define MAX_SEQNO 1073741824
88 void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
90 vpn_packet_t pkt1, pkt2;
91 vpn_packet_t *pkt[] = {&pkt1, &pkt2, &pkt1, &pkt2};
93 vpn_packet_t *outpkt = pkt[0];
95 long int complen = MTU + 12;
97 char hmac[EVP_MAX_MD_SIZE];
99 /* Check the message authentication code */
101 if(myself->digest && myself->maclength)
103 inpkt->len -= myself->maclength;
104 HMAC(myself->digest, myself->key, myself->keylength, (char *)&inpkt->seqno, inpkt->len, hmac, NULL);
105 if(memcmp(hmac, (char *)&inpkt->seqno + inpkt->len, myself->maclength))
107 if(debug_lvl >= DEBUG_TRAFFIC)
108 syslog(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"), n->name, n->hostname);
113 /* Decrypt the packet */
117 outpkt = pkt[nextpkt++];
119 EVP_DecryptInit(&ctx, myself->cipher, myself->key, myself->key + myself->cipher->key_len);
120 EVP_DecryptUpdate(&ctx, (char *)&outpkt->seqno, &outlen, (char *)&inpkt->seqno, inpkt->len);
121 EVP_DecryptFinal(&ctx, (char *)&outpkt->seqno + outlen, &outpad);
123 outpkt->len = outlen + outpad;
127 /* Check the sequence number */
129 inpkt->len -= sizeof(inpkt->seqno);
130 inpkt->seqno = ntohl(inpkt->seqno);
132 if(inpkt->seqno <= n->received_seqno)
134 if(debug_lvl >= DEBUG_TRAFFIC)
135 syslog(LOG_DEBUG, _("Got late or replayed packet from %s (%s), seqno %d"), n->name, n->hostname, inpkt->seqno);
139 n->received_seqno = inpkt->seqno;
141 if(n->received_seqno > MAX_SEQNO)
144 /* Decompress the packet */
146 if(myself->compression)
148 outpkt = pkt[nextpkt++];
150 if(uncompress(outpkt->data, &complen, inpkt->data, inpkt->len) != Z_OK)
152 syslog(LOG_ERR, _("Error while uncompressing packet from %s (%s)"), n->name, n->hostname);
156 outpkt->len = complen;
160 receive_packet(n, inpkt);
164 void receive_tcppacket(connection_t *c, char *buffer, int len)
169 memcpy(outpkt.data, buffer, len);
171 receive_packet(c->node, &outpkt);
175 void receive_packet(node_t *n, vpn_packet_t *packet)
178 if(debug_lvl >= DEBUG_TRAFFIC)
179 syslog(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"), packet->len, n->name, n->hostname);
181 route_incoming(n, packet);
185 void send_udppacket(node_t *n, vpn_packet_t *inpkt)
187 vpn_packet_t pkt1, pkt2;
188 vpn_packet_t *pkt[] = {&pkt1, &pkt2, &pkt1, &pkt2};
190 vpn_packet_t *outpkt;
193 long int complen = MTU + 12;
196 static int priority = 0;
200 /* Make sure we have a valid key */
202 if(!n->status.validkey)
204 if(debug_lvl >= DEBUG_TRAFFIC)
205 syslog(LOG_INFO, _("No valid key known yet for %s (%s), queueing packet"),
206 n->name, n->hostname);
208 /* Since packet is on the stack of handle_tap_input(),
209 we have to make a copy of it first. */
211 copy = xmalloc(sizeof(vpn_packet_t));
212 memcpy(copy, inpkt, sizeof(vpn_packet_t));
214 list_insert_tail(n->queue, copy);
216 if(n->queue->count > MAXQUEUELENGTH)
217 list_delete_head(n->queue);
219 if(!n->status.waitingforkey)
220 send_req_key(n->nexthop->connection, myself, n);
222 n->status.waitingforkey = 1;
227 origlen = inpkt->len;
228 origpriority = inpkt->priority;
230 /* Compress the packet */
234 outpkt = pkt[nextpkt++];
236 if(compress2(outpkt->data, &complen, inpkt->data, inpkt->len, n->compression) != Z_OK)
238 syslog(LOG_ERR, _("Error while compressing packet to %s (%s)"), n->name, n->hostname);
242 outpkt->len = complen;
246 /* Add sequence number */
248 inpkt->seqno = htonl(++(n->sent_seqno));
249 inpkt->len += sizeof(inpkt->seqno);
251 /* Encrypt the packet */
255 outpkt = pkt[nextpkt++];
257 EVP_EncryptInit(&ctx, n->cipher, n->key, n->key + n->cipher->key_len);
258 EVP_EncryptUpdate(&ctx, (char *)&outpkt->seqno, &outlen, (char *)&inpkt->seqno, inpkt->len);
259 EVP_EncryptFinal(&ctx, (char *)&outpkt->seqno + outlen, &outpad);
261 outpkt->len = outlen + outpad;
265 /* Add the message authentication code */
267 if(n->digest && n->maclength)
269 HMAC(n->digest, n->key, n->keylength, (char *)&inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len, &outlen);
270 inpkt->len += n->maclength;
273 /* Determine which socket we have to use */
275 for(sock = 0; sock < listen_sockets; sock++)
276 if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
279 if(sock >= listen_sockets)
280 sock = 0; /* If none is available, just use the first and hope for the best. */
282 /* Send the packet */
284 #if defined(SOL_IP) && defined(IP_TOS)
285 if(priorityinheritance && origpriority != priority && listen_socket[sock].sa.sa.sa_family == AF_INET)
287 priority = origpriority;
288 if(debug_lvl >= DEBUG_TRAFFIC)
289 syslog(LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
290 if(setsockopt(sock, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
291 syslog(LOG_ERR, _("System call `%s' failed: %s"), "setsockopt", strerror(errno));
295 if((sendto(listen_socket[sock].udp, (char *)&inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0)
297 syslog(LOG_ERR, _("Error sending packet to %s (%s): %s"),
298 n->name, n->hostname, strerror(errno));
302 inpkt->len = origlen;
307 send a packet to the given vpn ip.
309 void send_packet(node_t *n, vpn_packet_t *packet)
313 if(debug_lvl >= DEBUG_TRAFFIC)
314 syslog(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
315 packet->len, n->name, n->hostname);
319 if(debug_lvl >= DEBUG_TRAFFIC)
321 syslog(LOG_NOTICE, _("Packet is looping back to us!"));
327 if(!n->status.reachable)
329 if(debug_lvl >= DEBUG_TRAFFIC)
330 syslog(LOG_INFO, _("Node %s (%s) is not reachable"),
331 n->name, n->hostname);
335 via = (n->via == myself)?n->nexthop:n->via;
337 if(via != n && debug_lvl >= DEBUG_TRAFFIC)
338 syslog(LOG_ERR, _("Sending packet to %s via %s (%s)"),
339 n->name, via->name, n->via->hostname);
341 if((myself->options | via->options) & OPTION_TCPONLY)
343 if(send_tcppacket(via->connection, packet))
344 terminate_connection(via->connection, 1);
347 send_udppacket(via, packet);
350 /* Broadcast a packet using the minimum spanning tree */
352 void broadcast_packet(node_t *from, vpn_packet_t *packet)
357 if(debug_lvl >= DEBUG_TRAFFIC)
358 syslog(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
359 packet->len, from->name, from->hostname);
361 for(node = connection_tree->head; node; node = node->next)
363 c = (connection_t *)node->data;
364 if(c->status.active && c->status.mst && c != from->nexthop->connection)
365 send_packet(c->node, packet);
370 void flush_queue(node_t *n)
372 list_node_t *node, *next;
374 if(debug_lvl >= DEBUG_TRAFFIC)
375 syslog(LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname);
377 for(node = n->queue->head; node; node = next)
380 send_udppacket(n, (vpn_packet_t *)node->data);
381 list_delete_node(n->queue, node);
386 void handle_incoming_vpn_data(int sock)
389 int x, l = sizeof(x);
392 socklen_t fromlen = sizeof(from);
395 if(getsockopt(sock, SOL_SOCKET, SO_ERROR, &x, &l) < 0)
397 syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%s"),
398 __FILE__, __LINE__, sock, strerror(errno));
404 syslog(LOG_ERR, _("Incoming data socket error: %s"), strerror(x));
408 if((pkt.len = recvfrom(sock, (char *)&pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen)) <= 0)
410 syslog(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
414 sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
416 n = lookup_node_udp(&from);
420 hostname = sockaddr2hostname(&from);
421 syslog(LOG_WARNING, _("Received UDP packet from unknown source %s"), hostname);
427 n->connection->last_ping_time = now;
429 receive_udppacket(n, &pkt);