2 net_packet.c -- Handles in- and outgoing VPN packets
3 Copyright (C) 1998-2002 Ivo Timmermans <itimmermans@bigfoot.com>,
4 2000-2002 Guus Sliepen <guus@sliepen.warande.net>
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 1.1.2.7 2002/03/01 14:09:31 guus Exp $
28 #include <netinet/in.h>
30 #include <netinet/ip.h>
31 #include <netinet/tcp.h>
38 #include <sys/types.h>
41 #include <sys/ioctl.h>
42 /* SunOS really wants sys/socket.h BEFORE net/if.h,
43 and FreeBSD wants these lines below the rest. */
44 #include <arpa/inet.h>
45 #include <sys/socket.h>
48 #include <openssl/rand.h>
49 #include <openssl/evp.h>
50 #include <openssl/pem.h>
51 #include <openssl/hmac.h>
53 #ifndef HAVE_RAND_PSEUDO_BYTES
54 #define RAND_pseudo_bytes RAND_bytes
65 #include "connection.h"
83 #define MAX_SEQNO 1073741824
87 void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
89 vpn_packet_t pkt1, pkt2;
90 vpn_packet_t *pkt[] = {&pkt1, &pkt2, &pkt1, &pkt2};
92 vpn_packet_t *outpkt = pkt[0];
94 long int complen = MTU + 12;
96 char hmac[EVP_MAX_MD_SIZE];
98 /* Check the message authentication code */
100 if(myself->digest && myself->maclength)
102 inpkt->len -= myself->maclength;
103 HMAC(myself->digest, myself->key, myself->keylength, (char *)&inpkt->seqno, inpkt->len, hmac, NULL);
104 if(memcmp(hmac, (char *)&inpkt->seqno + inpkt->len, myself->maclength))
106 syslog(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"), n->name, n->hostname);
111 /* Decrypt the packet */
115 outpkt = pkt[nextpkt++];
117 EVP_DecryptInit(&ctx, myself->cipher, myself->key, myself->key + myself->cipher->key_len);
118 EVP_DecryptUpdate(&ctx, (char *)&outpkt->seqno, &outlen, (char *)&inpkt->seqno, inpkt->len);
119 EVP_DecryptFinal(&ctx, (char *)&outpkt->seqno + outlen, &outpad);
121 outpkt->len = outlen + outpad;
125 /* Check the sequence number */
127 inpkt->len -= sizeof(inpkt->seqno);
128 inpkt->seqno = ntohl(inpkt->seqno);
130 if(inpkt->seqno <= n->received_seqno)
132 syslog(LOG_DEBUG, _("Got late or replayed packet from %s (%s), seqno %d"), n->name, n->hostname, inpkt->seqno);
136 n->received_seqno = inpkt->seqno;
138 if(n->received_seqno > MAX_SEQNO)
141 /* Decompress the packet */
143 if(myself->compression)
145 outpkt = pkt[nextpkt++];
147 if(uncompress(outpkt->data, &complen, inpkt->data, inpkt->len) != Z_OK)
149 syslog(LOG_ERR, _("Error while uncompressing packet from %s (%s)"), n->name, n->hostname);
153 outpkt->len = complen;
157 receive_packet(n, inpkt);
161 void receive_tcppacket(connection_t *c, char *buffer, int len)
166 memcpy(outpkt.data, buffer, len);
168 receive_packet(c->node, &outpkt);
172 void receive_packet(node_t *n, vpn_packet_t *packet)
175 if(debug_lvl >= DEBUG_TRAFFIC)
176 syslog(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"), packet->len, n->name, n->hostname);
178 route_incoming(n, packet);
182 void send_udppacket(node_t *n, vpn_packet_t *inpkt)
184 vpn_packet_t pkt1, pkt2;
185 vpn_packet_t *pkt[] = {&pkt1, &pkt2, &pkt1, &pkt2};
187 vpn_packet_t *outpkt;
190 long int complen = MTU + 12;
193 static int priority = 0;
196 if(!n->status.validkey)
198 if(debug_lvl >= DEBUG_TRAFFIC)
199 syslog(LOG_INFO, _("No valid key known yet for %s (%s), queueing packet"),
200 n->name, n->hostname);
202 /* Since packet is on the stack of handle_tap_input(),
203 we have to make a copy of it first. */
205 copy = xmalloc(sizeof(vpn_packet_t));
206 memcpy(copy, inpkt, sizeof(vpn_packet_t));
208 list_insert_tail(n->queue, copy);
210 if(!n->status.waitingforkey)
211 send_req_key(n->nexthop->connection, myself, n);
216 origlen = inpkt->len;
217 origpriority = inpkt->priority;
219 /* Compress the packet */
223 outpkt = pkt[nextpkt++];
225 if(compress2(outpkt->data, &complen, inpkt->data, inpkt->len, n->compression) != Z_OK)
227 syslog(LOG_ERR, _("Error while compressing packet to %s (%s)"), n->name, n->hostname);
231 outpkt->len = complen;
235 /* Add sequence number */
237 inpkt->seqno = htonl(++(n->sent_seqno));
238 inpkt->len += sizeof(inpkt->seqno);
240 /* Encrypt the packet */
244 outpkt = pkt[nextpkt++];
246 EVP_EncryptInit(&ctx, n->cipher, n->key, n->key + n->cipher->key_len);
247 EVP_EncryptUpdate(&ctx, (char *)&outpkt->seqno, &outlen, (char *)&inpkt->seqno, inpkt->len);
248 EVP_EncryptFinal(&ctx, (char *)&outpkt->seqno + outlen, &outpad);
250 outpkt->len = outlen + outpad;
254 /* Add the message authentication code */
256 if(n->digest && n->maclength)
258 HMAC(n->digest, n->key, n->keylength, (char *)&inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len, &outlen);
259 inpkt->len += n->maclength;
262 /* Send the packet */
264 if(priorityinheritance && origpriority != priority)
266 priority = origpriority;
267 if(debug_lvl >= DEBUG_TRAFFIC)
268 syslog(LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
269 if(setsockopt(udp_socket[0], SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
270 syslog(LOG_ERR, _("System call `%s' failed: %s"), "setsockopt", strerror(errno));
273 if((sendto(udp_socket[0], (char *)&inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0)
275 syslog(LOG_ERR, _("Error sending packet to %s (%s): %s"),
276 n->name, n->hostname, strerror(errno));
280 inpkt->len = origlen;
285 send a packet to the given vpn ip.
287 void send_packet(node_t *n, vpn_packet_t *packet)
291 if(debug_lvl >= DEBUG_TRAFFIC)
292 syslog(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
293 packet->len, n->name, n->hostname);
297 if(debug_lvl >= DEBUG_TRAFFIC)
299 syslog(LOG_NOTICE, _("Packet is looping back to us!"));
305 if(!n->status.reachable)
307 if(debug_lvl >= DEBUG_TRAFFIC)
308 syslog(LOG_INFO, _("Node %s (%s) is not reachable"),
309 n->name, n->hostname);
313 via = (n->via == myself)?n->nexthop:n->via;
315 if(via != n && debug_lvl >= DEBUG_TRAFFIC)
316 syslog(LOG_ERR, _("Sending packet to %s via %s (%s)"),
317 n->name, via->name, n->via->hostname);
319 if((myself->options | via->options) & OPTION_TCPONLY)
321 if(send_tcppacket(via->connection, packet))
322 terminate_connection(via->connection, 1);
325 send_udppacket(via, packet);
328 /* Broadcast a packet using the minimum spanning tree */
330 void broadcast_packet(node_t *from, vpn_packet_t *packet)
335 if(debug_lvl >= DEBUG_TRAFFIC)
336 syslog(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
337 packet->len, from->name, from->hostname);
339 for(node = connection_tree->head; node; node = node->next)
341 c = (connection_t *)node->data;
342 if(c->status.active && c->status.mst && c != from->nexthop->connection)
343 send_packet(c->node, packet);
348 void flush_queue(node_t *n)
350 list_node_t *node, *next;
352 if(debug_lvl >= DEBUG_TRAFFIC)
353 syslog(LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname);
355 for(node = n->queue->head; node; node = next)
358 send_udppacket(n, (vpn_packet_t *)node->data);
359 list_delete_node(n->queue, node);
364 void handle_incoming_vpn_data(int sock)
367 int x, l = sizeof(x);
370 socklen_t fromlen = sizeof(from);
373 if(getsockopt(sock, SOL_SOCKET, SO_ERROR, &x, &l) < 0)
375 syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%s"),
376 __FILE__, __LINE__, sock, strerror(errno));
382 syslog(LOG_ERR, _("Incoming data socket error: %s"), strerror(x));
386 if((pkt.len = recvfrom(sock, (char *)&pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen)) <= 0)
388 syslog(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
392 n = lookup_node_udp(&from);
396 hostname = sockaddr2hostname(&from);
397 syslog(LOG_WARNING, _("Received UDP packet from unknown source %s"), hostname);
403 n->connection->last_ping_time = now;
405 receive_udppacket(n, &pkt);