--- /dev/null
+/*
+ net_packet.c -- Handles in- and outgoing VPN packets
+ Copyright (C) 1998-2002 Ivo Timmermans <itimmermans@bigfoot.com>,
+ 2000-2002 Guus Sliepen <guus@sliepen.warande.net>
+
+ 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: net_packet.c,v 1.1 2002/04/28 12:46:26 zarq Exp $
+*/
+
+#include "config.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#ifdef HAVE_LINUX
+ #include <netinet/ip.h>
+ #include <netinet/tcp.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+/* SunOS really wants sys/socket.h BEFORE net/if.h,
+ and FreeBSD wants these lines below the rest. */
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <net/if.h>
+
+#include <openssl/rand.h>
+#include <openssl/evp.h>
+#include <openssl/pem.h>
+#include <openssl/hmac.h>
+
+#ifndef HAVE_RAND_PSEUDO_BYTES
+#define RAND_pseudo_bytes RAND_bytes
+#endif
+
+#include <zlib.h>
+
+#include <utils.h>
+#include <xalloc.h>
+#include <avl_tree.h>
+#include <list.h>
+
+#include "conf.h"
+#include "connection.h"
+#include "meta.h"
+#include "net.h"
+#include "netutl.h"
+#include "process.h"
+#include "protocol.h"
+#include "subnet.h"
+#include "graph.h"
+#include "process.h"
+#include "route.h"
+#include "device.h"
+#include "event.h"
+#include "logging.h"
+
+#include "system.h"
+
+int keylifetime = 0;
+int keyexpires = 0;
+
+#define MAX_SEQNO 1073741824
+
+/* VPN packet I/O */
+
+void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
+{
+ 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;
+ long int complen = MTU + 12;
+ EVP_CIPHER_CTX ctx;
+ char hmac[EVP_MAX_MD_SIZE];
+cp
+ /* 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))
+ {
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"), n->name, n->hostname);
+ return;
+ }
+ }
+
+ /* Decrypt the packet */
+
+ if(myself->cipher)
+ {
+ outpkt = pkt[nextpkt++];
+
+ EVP_DecryptInit(&ctx, myself->cipher, myself->key, myself->key + myself->cipher->key_len);
+ EVP_DecryptUpdate(&ctx, (char *)&outpkt->seqno, &outlen, (char *)&inpkt->seqno, inpkt->len);
+ EVP_DecryptFinal(&ctx, (char *)&outpkt->seqno + outlen, &outpad);
+
+ outpkt->len = outlen + outpad;
+ inpkt = outpkt;
+ }
+
+ /* Check the sequence number */
+
+ inpkt->len -= sizeof(inpkt->seqno);
+ inpkt->seqno = ntohl(inpkt->seqno);
+
+ if(inpkt->seqno <= n->received_seqno)
+ {
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_DEBUG, _("Got late or replayed packet from %s (%s), seqno %d"), n->name, n->hostname, inpkt->seqno);
+ return;
+ }
+
+ n->received_seqno = inpkt->seqno;
+
+ if(n->received_seqno > MAX_SEQNO)
+ keyexpires = 0;
+
+ /* Decompress the packet */
+
+ if(myself->compression)
+ {
+ outpkt = pkt[nextpkt++];
+
+ if(uncompress(outpkt->data, &complen, inpkt->data, inpkt->len) != Z_OK)
+ {
+ syslog(LOG_ERR, _("Error while uncompressing packet from %s (%s)"), n->name, n->hostname);
+ return;
+ }
+
+ outpkt->len = complen;
+ inpkt = outpkt;
+ }
+
+ receive_packet(n, inpkt);
+cp
+}
+
+void receive_tcppacket(connection_t *c, char *buffer, int len)
+{
+ vpn_packet_t outpkt;
+cp
+ outpkt.len = len;
+ memcpy(outpkt.data, buffer, len);
+
+ receive_packet(c->node, &outpkt);
+cp
+}
+
+void receive_packet(node_t *n, vpn_packet_t *packet)
+{
+cp
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"), packet->len, n->name, n->hostname);
+cp
+}
+
+void send_udppacket(node_t *n, vpn_packet_t *inpkt)
+{
+ 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;
+ long int complen = MTU + 12;
+ EVP_CIPHER_CTX ctx;
+ vpn_packet_t *copy;
+ static int priority = 0;
+ int origpriority;
+ int sock;
+cp
+ /* Make sure we have a valid key */
+
+ if(!n->status.validkey)
+ {
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_INFO, _("No valid key known yet for %s (%s), queueing packet"),
+ n->name, n->hostname);
+
+ /* Since packet is on the stack of handle_tap_input(),
+ we have to make a copy of it first. */
+
+ copy = xmalloc(sizeof(vpn_packet_t));
+ memcpy(copy, inpkt, sizeof(vpn_packet_t));
+
+ list_insert_tail(n->queue, copy);
+
+ if(n->queue->count > MAXQUEUELENGTH)
+ list_delete_head(n->queue);
+
+ if(!n->status.waitingforkey)
+ send_req_key(n->nexthop->connection, myself, n);
+
+ n->status.waitingforkey = 1;
+
+ return;
+ }
+
+ origlen = inpkt->len;
+ origpriority = inpkt->priority;
+
+ /* Compress the packet */
+
+ if(n->compression)
+ {
+ outpkt = pkt[nextpkt++];
+
+ if(compress2(outpkt->data, &complen, inpkt->data, inpkt->len, n->compression) != Z_OK)
+ {
+ syslog(LOG_ERR, _("Error while compressing packet to %s (%s)"), n->name, n->hostname);
+ return;
+ }
+
+ outpkt->len = complen;
+ inpkt = outpkt;
+ }
+
+ /* Add sequence number */
+
+ inpkt->seqno = htonl(++(n->sent_seqno));
+ inpkt->len += sizeof(inpkt->seqno);
+
+ /* Encrypt the packet */
+
+ if(n->cipher)
+ {
+ outpkt = pkt[nextpkt++];
+
+ EVP_EncryptInit(&ctx, n->cipher, n->key, n->key + n->cipher->key_len);
+ EVP_EncryptUpdate(&ctx, (char *)&outpkt->seqno, &outlen, (char *)&inpkt->seqno, inpkt->len);
+ EVP_EncryptFinal(&ctx, (char *)&outpkt->seqno + outlen, &outpad);
+
+ outpkt->len = outlen + outpad;
+ inpkt = outpkt;
+ }
+
+ /* Add the message authentication code */
+
+ 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)
+ if(priorityinheritance && origpriority != priority && listen_socket[sock].sa.sa.sa_family == AF_INET)
+ {
+ priority = origpriority;
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
+ if(setsockopt(sock, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
+ syslog(LOG_ERR, _("System call `%s' failed: %s"), "setsockopt", strerror(errno));
+ }
+#endif
+
+ if((sendto(listen_socket[sock].udp, (char *)&inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0)
+ {
+ syslog(LOG_ERR, _("Error sending packet to %s (%s): %s"),
+ n->name, n->hostname, strerror(errno));
+ return;
+ }
+
+ inpkt->len = origlen;
+cp
+}
+
+/*
+ send a packet to the given vpn ip.
+*/
+void send_packet(node_t *n, vpn_packet_t *packet)
+{
+ node_t *via;
+cp
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
+ packet->len, n->name, n->hostname);
+
+ if(n == myself)
+ {
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ {
+ syslog(LOG_NOTICE, _("Packet is looping back to us!"));
+ }
+
+ return;
+ }
+
+ if(!n->status.reachable)
+ {
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_INFO, _("Node %s (%s) is not reachable"),
+ n->name, n->hostname);
+ return;
+ }
+
+ via = (n->via == myself)?n->nexthop:n->via;
+
+ if(via != n && debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_ERR, _("Sending packet to %s via %s (%s)"),
+ n->name, via->name, n->via->hostname);
+
+ if((myself->options | via->options) & OPTION_TCPONLY)
+ {
+ if(send_tcppacket(via->connection, packet))
+ terminate_connection(via->connection, 1);
+ }
+ else
+ send_udppacket(via, packet);
+}
+
+/* Broadcast a packet using the minimum spanning tree */
+
+void broadcast_packet(node_t *from, vpn_packet_t *packet)
+{
+ avl_node_t *node;
+ connection_t *c;
+cp
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
+ packet->len, from->name, from->hostname);
+
+ for(node = connection_tree->head; node; node = node->next)
+ {
+ c = (connection_t *)node->data;
+ if(c->status.active && c->status.mst && c != from->nexthop->connection)
+ send_packet(c->node, packet);
+ }
+cp
+}
+
+void flush_queue(node_t *n)
+{
+ list_node_t *node, *next;
+cp
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname);
+
+ for(node = n->queue->head; node; node = next)
+ {
+ next = node->next;
+ send_udppacket(n, (vpn_packet_t *)node->data);
+ list_delete_node(n->queue, node);
+ }
+cp
+}
+
+void handle_incoming_vpn_data(int sock)
+{
+ vpn_packet_t pkt;
+ int x, l = sizeof(x);
+ char *hostname;
+ sockaddr_t from;
+ socklen_t fromlen = sizeof(from);
+ node_t *n;
+cp
+ if(getsockopt(sock, SOL_SOCKET, SO_ERROR, &x, &l) < 0)
+ {
+ syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%s"),
+ __FILE__, __LINE__, sock, strerror(errno));
+ cp_trace();
+ exit(1);
+ }
+ if(x)
+ {
+ syslog(LOG_ERR, _("Incoming data socket error: %s"), strerror(x));
+ return;
+ }
+
+ if((pkt.len = recvfrom(sock, (char *)&pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen)) <= 0)
+ {
+ syslog(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
+ return;
+ }
+
+ sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
+
+ n = lookup_node_udp(&from);
+
+ if(!n)
+ {
+ hostname = sockaddr2hostname(&from);
+ syslog(LOG_WARNING, _("Received UDP packet from unknown source %s"), hostname);
+ free(hostname);
+ return;
+ }
+
+ if(n->connection)
+ n->connection->last_ping_time = now;
+
+ receive_udppacket(n, &pkt);
+cp
+}
+
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