tinc/src/net_packet.c

514 lines
13 KiB
C
Raw Normal View History

/*
net_packet.c -- Handles in- and outgoing VPN packets
Copyright (C) 1998-2004 Ivo Timmermans <ivo@tinc-vpn.org>,
2000-2004 Guus Sliepen <guus@tinc-vpn.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id$
*/
#include "system.h"
#include <openssl/rand.h>
2003-10-11 12:16:13 +00:00
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/hmac.h>
#include <zlib.h>
#include <lzo1x.h>
#include "avl_tree.h"
#include "conf.h"
#include "connection.h"
#include "device.h"
#include "ethernet.h"
#include "event.h"
#include "graph.h"
#include "list.h"
#include "logger.h"
#include "net.h"
#include "netutl.h"
#include "protocol.h"
#include "process.h"
#include "route.h"
#include "utils.h"
#include "xalloc.h"
#ifdef WSAEMSGSIZE
#define EMSGSIZE WSAEMSGSIZE
#endif
int keylifetime = 0;
int keyexpires = 0;
EVP_CIPHER_CTX packet_ctx;
static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
static void send_udppacket(node_t *, vpn_packet_t *);
#define MAX_SEQNO 1073741824
void send_mtu_probe(node_t *n)
{
vpn_packet_t packet;
int len, i;
cp();
n->mtuprobes++;
n->mtuevent = NULL;
if(n->mtuprobes >= 10 && !n->minmtu) {
ifdebug(TRAFFIC) logger(LOG_INFO, _("No response to MTU probes from %s (%s)"), n->name, n->hostname);
return;
}
for(i = 0; i < 3; i++) {
if(n->mtuprobes >= 30 || n->minmtu >= n->maxmtu) {
n->mtu = n->minmtu;
ifdebug(TRAFFIC) logger(LOG_INFO, _("Fixing MTU of %s (%s) to %d after %d probes"), n->name, n->hostname, n->mtu, n->mtuprobes);
return;
}
len = n->minmtu + 1 + random() % (n->maxmtu - n->minmtu);
if(len < 64)
len = 64;
memset(packet.data, 0, 14);
RAND_pseudo_bytes(packet.data + 14, len - 14);
packet.len = len;
ifdebug(TRAFFIC) logger(LOG_INFO, _("Sending MTU probe length %d to %s (%s)"), len, n->name, n->hostname);
send_udppacket(n, &packet);
}
n->mtuevent = xmalloc(sizeof(*n->mtuevent));
n->mtuevent->handler = (event_handler_t)send_mtu_probe;
n->mtuevent->data = n;
n->mtuevent->time = now + 1;
event_add(n->mtuevent);
}
void mtu_probe_h(node_t *n, vpn_packet_t *packet) {
ifdebug(TRAFFIC) logger(LOG_INFO, _("Got MTU probe length %d from %s (%s)"), packet->len, n->name, n->hostname);
if(!packet->data[0]) {
packet->data[0] = 1;
send_packet(n, packet);
} else {
if(n->minmtu < packet->len)
n->minmtu = packet->len;
}
}
static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level)
{
if(level == 10) {
2003-05-07 11:21:58 +00:00
lzo_uint lzolen = MAXSIZE;
lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
return lzolen;
} else if(level < 10) {
unsigned long destlen = MAXSIZE;
if(compress2(dest, &destlen, source, len, level) == Z_OK)
return destlen;
else
return -1;
} else {
2003-05-07 11:21:58 +00:00
lzo_uint lzolen = MAXSIZE;
lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
return lzolen;
}
return -1;
}
static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level)
{
if(level > 9) {
2003-05-07 11:21:58 +00:00
lzo_uint lzolen = MAXSIZE;
if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
return lzolen;
else
return -1;
} else {
unsigned long destlen = MAXSIZE;
if(uncompress(dest, &destlen, source, len) == Z_OK)
return destlen;
else
return -1;
}
return -1;
}
/* VPN packet I/O */
static void receive_packet(node_t *n, vpn_packet_t *packet)
{
cp();
ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"),
packet->len, n->name, n->hostname);
route(n, packet);
}
static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
{
2002-09-09 21:25:28 +00:00
vpn_packet_t pkt1, pkt2;
vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
int nextpkt = 0;
vpn_packet_t *outpkt = pkt[0];
int outlen, outpad;
char hmac[EVP_MAX_MD_SIZE];
2003-10-11 12:16:13 +00:00
int i;
2002-09-09 21:25:28 +00:00
cp();
/* Check packet length */
if(inpkt->len < sizeof(inpkt->seqno) + myself->maclength) {
ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got too short packet from %s (%s)"),
n->name, n->hostname);
return;
}
/* Check the message authentication code */
if(myself->digest && myself->maclength) {
inpkt->len -= myself->maclength;
HMAC(myself->digest, myself->key, myself->keylength,
(char *) &inpkt->seqno, inpkt->len, hmac, NULL);
if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, myself->maclength)) {
ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"),
n->name, n->hostname);
return;
}
}
2002-09-09 21:25:28 +00:00
/* Decrypt the packet */
if(myself->cipher) {
outpkt = pkt[nextpkt++];
2003-10-11 12:16:13 +00:00
if(!EVP_DecryptInit_ex(&packet_ctx, NULL, NULL, NULL, NULL)
|| !EVP_DecryptUpdate(&packet_ctx, (char *) &outpkt->seqno, &outlen,
(char *) &inpkt->seqno, inpkt->len)
|| !EVP_DecryptFinal_ex(&packet_ctx, (char *) &outpkt->seqno + outlen, &outpad)) {
ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Error decrypting packet from %s (%s): %s"),
n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
return;
}
2002-09-09 21:25:28 +00:00
outpkt->len = outlen + outpad;
inpkt = outpkt;
}
/* Check the sequence number */
inpkt->len -= sizeof(inpkt->seqno);
inpkt->seqno = ntohl(inpkt->seqno);
2003-04-18 21:18:36 +00:00
if(inpkt->seqno != n->received_seqno + 1) {
if(inpkt->seqno >= n->received_seqno + sizeof(n->late) * 8) {
logger(LOG_WARNING, _("Lost %d packets from %s (%s)"),
2003-04-18 21:18:36 +00:00
inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
memset(n->late, 0, sizeof(n->late));
} else if (inpkt->seqno <= n->received_seqno) {
if(inpkt->seqno <= n->received_seqno - sizeof(n->late) * 8 || !(n->late[(inpkt->seqno / 8) % sizeof(n->late)] & (1 << inpkt->seqno % 8))) {
logger(LOG_WARNING, _("Got late or replayed packet from %s (%s), seqno %d, last received %d"),
n->name, n->hostname, inpkt->seqno, n->received_seqno);
return;
}
} else {
for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
n->late[(inpkt->seqno / 8) % sizeof(n->late)] |= 1 << i % 8;
2003-04-18 21:18:36 +00:00
}
2002-09-09 21:25:28 +00:00
}
2003-04-18 21:18:36 +00:00
n->late[(inpkt->seqno / 8) % sizeof(n->late)] &= ~(1 << inpkt->seqno % 8);
if(n->received_seqno > inpkt->seqno)
n->received_seqno = inpkt->seqno;
2003-04-18 21:18:36 +00:00
2002-09-09 21:25:28 +00:00
if(n->received_seqno > MAX_SEQNO)
keyexpires = 0;
/* Decompress the packet */
if(myself->compression) {
outpkt = pkt[nextpkt++];
if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, myself->compression)) < 0) {
ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
n->name, n->hostname);
2002-09-09 21:25:28 +00:00
return;
}
inpkt = outpkt;
}
if(n->connection)
n->connection->last_ping_time = now;
if(!inpkt->data[12] && !inpkt->data[13])
mtu_probe_h(n, inpkt);
else
receive_packet(n, inpkt);
}
2002-09-09 22:33:31 +00:00
void receive_tcppacket(connection_t *c, char *buffer, int len)
{
2002-09-09 21:25:28 +00:00
vpn_packet_t outpkt;
cp();
2002-09-09 21:25:28 +00:00
outpkt.len = len;
memcpy(outpkt.data, buffer, len);
receive_packet(c->node, &outpkt);
}
static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
{
2002-09-09 21:25:28 +00:00
vpn_packet_t pkt1, pkt2;
vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
int nextpkt = 0;
vpn_packet_t *outpkt;
int origlen;
int outlen, outpad;
vpn_packet_t *copy;
static int priority = 0;
int origpriority;
int sock;
2002-09-09 21:25:28 +00:00
cp();
2002-09-09 21:25:28 +00:00
/* Make sure we have a valid key */
2002-09-09 21:25:28 +00:00
if(!n->status.validkey) {
ifdebug(TRAFFIC) logger(LOG_INFO,
2002-09-09 21:25:28 +00:00
_("No valid key known yet for %s (%s), queueing packet"),
n->name, n->hostname);
2002-09-09 21:25:28 +00:00
/* Since packet is on the stack of handle_tap_input(), we have to make a copy of it first. */
*(copy = xmalloc(sizeof(*copy))) = *inpkt;
2002-09-09 21:25:28 +00:00
list_insert_tail(n->queue, copy);
2002-09-09 21:25:28 +00:00
if(n->queue->count > MAXQUEUELENGTH)
list_delete_head(n->queue);
2002-09-09 21:25:28 +00:00
if(!n->status.waitingforkey)
send_req_key(n->nexthop->connection, myself, n);
2003-07-22 20:55:21 +00:00
n->status.waitingforkey = true;
2002-09-09 21:25:28 +00:00
return;
}
2002-09-09 21:25:28 +00:00
origlen = inpkt->len;
origpriority = inpkt->priority;
2002-09-09 21:25:28 +00:00
/* Compress the packet */
2002-09-09 21:25:28 +00:00
if(n->compression) {
outpkt = pkt[nextpkt++];
if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->compression)) < 0) {
ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
2002-09-09 21:25:28 +00:00
n->name, n->hostname);
return;
}
2002-09-09 21:25:28 +00:00
inpkt = outpkt;
}
2002-09-09 21:25:28 +00:00
/* Add sequence number */
2002-09-09 21:25:28 +00:00
inpkt->seqno = htonl(++(n->sent_seqno));
inpkt->len += sizeof(inpkt->seqno);
2002-09-09 21:25:28 +00:00
/* Encrypt the packet */
2002-09-09 21:25:28 +00:00
if(n->cipher) {
outpkt = pkt[nextpkt++];
2003-10-11 12:16:13 +00:00
if(!EVP_EncryptInit_ex(&n->packet_ctx, NULL, NULL, NULL, NULL)
|| !EVP_EncryptUpdate(&n->packet_ctx, (char *) &outpkt->seqno, &outlen,
(char *) &inpkt->seqno, inpkt->len)
|| !EVP_EncryptFinal_ex(&n->packet_ctx, (char *) &outpkt->seqno + outlen, &outpad)) {
ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s): %s"),
n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
2003-12-24 10:48:15 +00:00
goto end;
}
2002-09-09 21:25:28 +00:00
outpkt->len = outlen + outpad;
inpkt = outpkt;
}
2002-09-09 21:25:28 +00:00
/* Add the message authentication code */
2002-09-09 21:25:28 +00:00
if(n->digest && n->maclength) {
HMAC(n->digest, n->key, n->keylength, (char *) &inpkt->seqno,
inpkt->len, (char *) &inpkt->seqno + inpkt->len, &outlen);
inpkt->len += n->maclength;
}
/* Determine which socket we have to use */
for(sock = 0; sock < listen_sockets; sock++)
if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
break;
if(sock >= listen_sockets)
sock = 0; /* If none is available, just use the first and hope for the best. */
/* Send the packet */
#if defined(SOL_IP) && defined(IP_TOS)
2002-09-09 21:25:28 +00:00
if(priorityinheritance && origpriority != priority
&& listen_socket[sock].sa.sa.sa_family == AF_INET) {
priority = origpriority;
ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
2002-11-14 22:09:03 +00:00
if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
2003-08-08 19:42:35 +00:00
logger(LOG_ERR, _("System call `%s' failed: %s"), "setsockopt", strerror(errno));
2002-09-09 21:25:28 +00:00
}
#endif
2002-09-09 21:25:28 +00:00
if((sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0) {
if(errno == EMSGSIZE) {
if(n->maxmtu >= origlen)
n->maxmtu = origlen - 1;
if(n->mtu >= origlen)
n->mtu = origlen - 1;
2003-12-24 10:48:15 +00:00
} else
logger(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name, n->hostname, strerror(errno));
2002-09-09 21:25:28 +00:00
}
2003-12-24 10:48:15 +00:00
end:
2002-09-09 21:25:28 +00:00
inpkt->len = origlen;
}
/*
send a packet to the given vpn ip.
*/
void send_packet(const node_t *n, vpn_packet_t *packet)
{
2002-09-09 21:25:28 +00:00
node_t *via;
cp();
if(n == myself) {
if(overwrite_mac)
memcpy(packet->data, mymac.x, ETH_ALEN);
write_packet(packet);
2002-09-09 21:25:28 +00:00
return;
}
ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
packet->len, n->name, n->hostname);
2002-09-09 21:25:28 +00:00
if(!n->status.reachable) {
ifdebug(TRAFFIC) logger(LOG_INFO, _("Node %s (%s) is not reachable"),
2002-09-09 21:25:28 +00:00
n->name, n->hostname);
return;
}
via = (n->via == myself) ? n->nexthop : n->via;
if(via != n)
ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet to %s via %s (%s)"),
2002-09-09 21:25:28 +00:00
n->name, via->name, n->via->hostname);
if((myself->options | via->options) & OPTION_TCPONLY) {
2003-07-22 20:55:21 +00:00
if(!send_tcppacket(via->connection, packet))
terminate_connection(via->connection, true);
2002-09-09 21:25:28 +00:00
} else
send_udppacket(via, packet);
}
/* Broadcast a packet using the minimum spanning tree */
void broadcast_packet(const node_t *from, vpn_packet_t *packet)
{
2002-09-09 21:25:28 +00:00
avl_node_t *node;
connection_t *c;
cp();
ifdebug(TRAFFIC) logger(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
2002-09-09 21:25:28 +00:00
packet->len, from->name, from->hostname);
for(node = connection_tree->head; node; node = node->next) {
2003-08-28 21:05:11 +00:00
c = node->data;
2002-09-09 21:25:28 +00:00
if(c->status.active && c->status.mst && c != from->nexthop->connection)
send_packet(c->node, packet);
}
}
2002-09-09 22:33:31 +00:00
void flush_queue(node_t *n)
{
2002-09-09 21:25:28 +00:00
list_node_t *node, *next;
cp();
ifdebug(TRAFFIC) logger(LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname);
2002-09-09 21:25:28 +00:00
for(node = n->queue->head; node; node = next) {
next = node->next;
2003-08-28 21:05:11 +00:00
send_udppacket(n, node->data);
2002-09-09 21:25:28 +00:00
list_delete_node(n->queue, node);
}
}
2002-02-26 23:26:41 +00:00
void handle_incoming_vpn_data(int sock)
{
2002-09-09 21:25:28 +00:00
vpn_packet_t pkt;
char *hostname;
sockaddr_t from;
socklen_t fromlen = sizeof(from);
node_t *n;
cp();
pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
if(pkt.len < 0) {
logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
2002-09-09 21:25:28 +00:00
return;
}
sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
n = lookup_node_udp(&from);
if(!n) {
hostname = sockaddr2hostname(&from);
logger(LOG_WARNING, _("Received UDP packet from unknown source %s"),
hostname);
2002-09-09 21:25:28 +00:00
free(hostname);
return;
}
receive_udppacket(n, &pkt);
}