Make sure broadcast packet reach the local network interface.
[tinc] / src / net_packet.c
index 79d3b18..ed49b0b 100644 (file)
@@ -1,7 +1,7 @@
 /*
     net_packet.c -- Handles in- and outgoing VPN packets
-    Copyright (C) 1998-2002 Ivo Timmermans <ivo@o2w.nl>,
-                  2000-2002 Guus Sliepen <guus@sliepen.eu.org>
+    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
     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 1.1.2.32 2003/07/06 23:16:28 guus Exp $
+    $Id$
 */
 
-#include "config.h"
-
-#include <errno.h>
-#include <fcntl.h>
-#include <netdb.h>
-#include <netinet/in.h>
-#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>
-#ifdef HAVE_NETINET_IN_SYSTM_H
-#include <netinet/in_systm.h>
-#endif
-#ifdef HAVE_NETINET_IP_H
-#include <netinet/ip.h>
-#endif
-#ifdef HAVE_NETINET_TCP_H
-#include <netinet/tcp.h>
-#endif
+#include "system.h"
 
 #include <openssl/rand.h>
+#include <openssl/err.h>
 #include <openssl/evp.h>
 #include <openssl/pem.h>
 #include <openssl/hmac.h>
 #include <zlib.h>
 #include <lzo1x.h>
 
-#include <utils.h>
-#include <xalloc.h>
-#include <avl_tree.h>
-#include <list.h>
-
+#include "avl_tree.h"
 #include "conf.h"
 #include "connection.h"
-#include "meta.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 "process.h"
 #include "protocol.h"
-#include "subnet.h"
-#include "graph.h"
 #include "process.h"
 #include "route.h"
-#include "device.h"
-#include "event.h"
-#include "logger.h"
+#include "utils.h"
+#include "xalloc.h"
 
-#include "system.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) {
@@ -133,10 +161,10 @@ static void receive_packet(node_t *n, vpn_packet_t *packet)
 {
        cp();
 
-       logger(DEBUG_TRAFFIC, LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"),
+       ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"),
                           packet->len, n->name, n->hostname);
 
-       route_incoming(n, packet);
+       route(n, packet);
 }
 
 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
@@ -151,6 +179,14 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 
        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) {
@@ -159,7 +195,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
                         (char *) &inpkt->seqno, inpkt->len, hmac, NULL);
 
                if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, myself->maclength)) {
-                       logger(DEBUG_TRAFFIC, LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"),
+                       ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"),
                                           n->name, n->hostname);
                        return;
                }
@@ -170,12 +206,14 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
        if(myself->cipher) {
                outpkt = pkt[nextpkt++];
 
-//             EVP_DecryptInit_ex(&packet_ctx, myself->cipher, NULL, myself->key,
-//                                             myself->key + myself->cipher->key_len);
-               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);
+               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;
+               }
                
                outpkt->len = outlen + outpad;
                inpkt = outpkt;
@@ -188,22 +226,26 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 
        if(inpkt->seqno != n->received_seqno + 1) {
                if(inpkt->seqno >= n->received_seqno + sizeof(n->late) * 8) {
-                       logger(DEBUG_ALWAYS, LOG_WARNING, _("Lost %d packets from %s (%s)"),
+                       logger(LOG_WARNING, _("Lost %d packets from %s (%s)"),
                                           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(DEBUG_ALWAYS, LOG_WARNING, _("Got late or replayed packet from %s (%s), seqno %d, last received %d"),
+                       if((n->received_seqno >= sizeof(n->late) * 8 && 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);
-                       } else
-                               for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
-                                       n->late[(inpkt->seqno / 8) % sizeof(n->late)] |= 1 << i % 8;
+                               return;
+                       }
+               } else {
+                       for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
+                               n->late[(i / 8) % sizeof(n->late)] |= 1 << i % 8;
                }
        }
        
-       n->received_seqno = inpkt->seqno;
-       n->late[(n->received_seqno / 8) % sizeof(n->late)] &= ~(1 << n->received_seqno % 8);
+       n->late[(inpkt->seqno / 8) % sizeof(n->late)] &= ~(1 << inpkt->seqno % 8);
+
+       if(inpkt->seqno > n->received_seqno)
+               n->received_seqno = inpkt->seqno;
                        
        if(n->received_seqno > MAX_SEQNO)
                keyexpires = 0;
@@ -214,15 +256,21 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
                outpkt = pkt[nextpkt++];
 
                if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, myself->compression)) < 0) {
-                       logger(DEBUG_ALWAYS, LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
-                                  n->name, n->hostname);
+                       ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
+                                                n->name, n->hostname);
                        return;
                }
 
                inpkt = outpkt;
        }
 
-       receive_packet(n, inpkt);
+       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);
 }
 
 void receive_tcppacket(connection_t *c, char *buffer, int len)
@@ -255,14 +303,13 @@ static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
        /* Make sure we have a valid key */
 
        if(!n->status.validkey) {
-               logger(DEBUG_TRAFFIC, LOG_INFO,
+               ifdebug(TRAFFIC) logger(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));
+               *(copy = xmalloc(sizeof(*copy))) = *inpkt;
 
                list_insert_tail(n->queue, copy);
 
@@ -272,7 +319,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
                if(!n->status.waitingforkey)
                        send_req_key(n->nexthop->connection, myself, n);
 
-               n->status.waitingforkey = 1;
+               n->status.waitingforkey = true;
 
                return;
        }
@@ -286,7 +333,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
                outpkt = pkt[nextpkt++];
 
                if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->compression)) < 0) {
-                       logger(DEBUG_ALWAYS, LOG_ERR, _("Error while compressing packet to %s (%s)"),
+                       ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
                                   n->name, n->hostname);
                        return;
                }
@@ -304,11 +351,14 @@ static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
        if(n->cipher) {
                outpkt = pkt[nextpkt++];
 
-//             EVP_EncryptInit_ex(&packet_ctx, n->cipher, NULL, n->key, n->key + n->cipher->key_len);
-               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);
+               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));
+                       goto end;
+               }
 
                outpkt->len = outlen + outpad;
                inpkt = outpkt;
@@ -337,41 +387,47 @@ static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
        if(priorityinheritance && origpriority != priority
           && listen_socket[sock].sa.sa.sa_family == AF_INET) {
                priority = origpriority;
-               logger(DEBUG_TRAFFIC, LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
+               ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
                if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority)))    /* SO_PRIORITY doesn't seem to work */
-                       logger(DEBUG_ALWAYS, LOG_ERR, _("System call `%s' failed: %s"), "setsockopt",
-                                  strerror(errno));
+                       logger(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) {
-               logger(DEBUG_ALWAYS, LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name,
-                          n->hostname, strerror(errno));
-               return;
+               if(errno == EMSGSIZE) {
+                       if(n->maxmtu >= origlen)
+                               n->maxmtu = origlen - 1;
+                       if(n->mtu >= origlen)
+                               n->mtu = origlen - 1;
+               } else
+                       logger(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name, n->hostname, strerror(errno));
        }
 
+end:
        inpkt->len = origlen;
 }
 
 /*
   send a packet to the given vpn ip.
 */
-void send_packet(node_t *n, vpn_packet_t *packet)
+void send_packet(const node_t *n, vpn_packet_t *packet)
 {
        node_t *via;
 
        cp();
 
-       logger(DEBUG_TRAFFIC, LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
-                          packet->len, n->name, n->hostname);
-
        if(n == myself) {
-               logger(DEBUG_TRAFFIC, LOG_NOTICE, _("Packet is looping back to us!"));
+               if(overwrite_mac)
+                        memcpy(packet->data, mymac.x, ETH_ALEN);
+               write_packet(packet);
                return;
        }
 
+       ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
+                          packet->len, n->name, n->hostname);
+
        if(!n->status.reachable) {
-               logger(DEBUG_TRAFFIC, LOG_INFO, _("Node %s (%s) is not reachable"),
+               ifdebug(TRAFFIC) logger(LOG_INFO, _("Node %s (%s) is not reachable"),
                                   n->name, n->hostname);
                return;
        }
@@ -379,30 +435,36 @@ void send_packet(node_t *n, vpn_packet_t *packet)
        via = (n->via == myself) ? n->nexthop : n->via;
 
        if(via != n)
-               logger(DEBUG_TRAFFIC, LOG_ERR, _("Sending packet to %s via %s (%s)"),
+               ifdebug(TRAFFIC) logger(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);
+               if(!send_tcppacket(via->connection, packet))
+                       terminate_connection(via->connection, true);
        } else
                send_udppacket(via, packet);
 }
 
 /* Broadcast a packet using the minimum spanning tree */
 
-void broadcast_packet(node_t *from, vpn_packet_t *packet)
+void broadcast_packet(const node_t *from, vpn_packet_t *packet)
 {
        avl_node_t *node;
        connection_t *c;
 
        cp();
 
-       logger(DEBUG_TRAFFIC, LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
+       ifdebug(TRAFFIC) logger(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
                           packet->len, from->name, from->hostname);
 
+       if(from != myself) {
+               if(overwrite_mac)
+                        memcpy(packet->data, mymac.x, ETH_ALEN);
+               write_packet(packet);
+       }
+
        for(node = connection_tree->head; node; node = node->next) {
-               c = (connection_t *) node->data;
+               c = node->data;
 
                if(c->status.active && c->status.mst && c != from->nexthop->connection)
                        send_packet(c->node, packet);
@@ -415,11 +477,11 @@ void flush_queue(node_t *n)
 
        cp();
 
-       logger(DEBUG_TRAFFIC, LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname);
+       ifdebug(TRAFFIC) logger(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);
+               send_udppacket(n, node->data);
                list_delete_node(n->queue, node);
        }
 }
@@ -427,7 +489,6 @@ void flush_queue(node_t *n)
 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);
@@ -435,22 +496,10 @@ void handle_incoming_vpn_data(int sock)
 
        cp();
 
-       if(getsockopt(sock, SOL_SOCKET, SO_ERROR, &x, &l) < 0) {
-               logger(DEBUG_ALWAYS, LOG_ERR, _("This is a bug: %s:%d: %d:%s"),
-                          __FILE__, __LINE__, sock, strerror(errno));
-               cp_trace();
-               exit(1);
-       }
-
-       if(x) {
-               logger(DEBUG_ALWAYS, LOG_ERR, _("Incoming data socket error: %s"), strerror(x));
-               return;
-       }
-
        pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
-       if(pkt.len <= 0) {
-               logger(DEBUG_ALWAYS, LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
+       if(pkt.len < 0) {
+               logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
                return;
        }
 
@@ -460,14 +509,11 @@ void handle_incoming_vpn_data(int sock)
 
        if(!n) {
                hostname = sockaddr2hostname(&from);
-               logger(DEBUG_ALWAYS, LOG_WARNING, _("Received UDP packet from unknown source %s"),
+               logger(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);
 }