Handle broadcast and multicast packets in router mode.
[tinc] / src / route.c
index 367926e..742fbc2 100644 (file)
@@ -1,7 +1,7 @@
 /*
     route.c -- routing
-    Copyright (C) 2000-2003 Ivo Timmermans <ivo@o2w.nl>,
-                  2000-2003 Guus Sliepen <guus@sliepen.eu.org>
+    Copyright (C) 2000-2005 Ivo Timmermans,
+                  2000-2006 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: route.c,v 1.1.2.73 2003/12/20 21:25:17 guus Exp $
+    $Id$
 */
 
 #include "system.h"
 
-#ifdef HAVE_NET_ETHERNET_H
-#include <net/ethernet.h>
-#endif
-#ifdef HAVE_NET_IF_ARP_H
-#include <net/if_arp.h>
-#endif
-#ifdef HAVE_NETINET_IP_ICMP_H
-#include <netinet/ip_icmp.h>
-#endif
-#ifdef HAVE_NETINET_ICMP6_H
-#include <netinet/icmp6.h>
-#endif
-#ifdef HAVE_NETINET_IF_ETHER_H
-#include <netinet/if_ether.h>
-#endif
-
 #include "avl_tree.h"
 #include "connection.h"
 #include "ethernet.h"
@@ -69,7 +53,7 @@ static const size_t opt_size = sizeof(struct nd_opt_hdr);
 
 /* RFC 1071 */
 
-static __inline__ uint16_t inet_checksum(void *data, int len, uint16_t prevsum)
+static uint16_t inet_checksum(void *data, int len, uint16_t prevsum)
 {
        uint16_t *p = data;
        uint32_t checksum = prevsum ^ 0xFFFF;
@@ -88,7 +72,7 @@ static __inline__ uint16_t inet_checksum(void *data, int len, uint16_t prevsum)
        return ~checksum;
 }
 
-static __inline__ bool ratelimit(int frequency) {
+static bool ratelimit(int frequency) {
        static time_t lasttime = 0;
        static int count = 0;
        
@@ -103,7 +87,7 @@ static __inline__ bool ratelimit(int frequency) {
        return false;
 }
 
-static __inline__ bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
+static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
        if(packet->len < length) {
                ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got too short packet from %s (%s)"), source->name, source->hostname);
                return false;
@@ -111,7 +95,7 @@ static __inline__ bool checklength(node_t *source, vpn_packet_t *packet, length_
                return true;
 }
        
-static __inline__ void learn_mac(mac_t *address)
+static void learn_mac(mac_t *address)
 {
        subnet_t *subnet;
        avl_node_t *node;
@@ -176,20 +160,26 @@ void age_subnets(void)
        }
 }
 
-static __inline__ void route_mac(node_t *source, vpn_packet_t *packet)
+static void route_mac(node_t *source, vpn_packet_t *packet)
 {
        subnet_t *subnet;
+       mac_t dest;
 
        cp();
 
+
        /* Learn source address */
 
-       if(source == myself)
-               learn_mac((mac_t *)(&packet->data[6]));
+       if(source == myself) {
+               mac_t src;
+               memcpy(&src, &packet->data[6], sizeof src);
+               learn_mac(&src);
+       }
 
        /* Lookup destination address */
 
-       subnet = lookup_subnet_mac((mac_t *)(&packet->data[0]));
+       memcpy(&dest, &packet->data[0], sizeof dest);
+       subnet = lookup_subnet_mac(&dest);
 
        if(!subnet) {
                broadcast_packet(source, packet);
@@ -276,21 +266,76 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
        send_packet(source, packet);
 }
 
-static __inline__ void route_ipv4_unicast(node_t *source, vpn_packet_t *packet)
+/* RFC 791 */
+
+static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet) {
+       struct ip ip;
+       vpn_packet_t fragment;
+       int len, maxlen, todo;
+       uint8_t *offset;
+       uint16_t ip_off, origf;
+       
+       cp();
+
+       memcpy(&ip, packet->data + ether_size, ip_size);
+       fragment.priority = packet->priority;
+
+       if(ip.ip_hl != ip_size / 4)
+               return;
+       
+       todo = ntohs(ip.ip_len) - ip_size;
+
+       if(ether_size + ip_size + todo != packet->len) {
+               ifdebug(TRAFFIC) logger(LOG_WARNING, _("Length of packet (%d) doesn't match length in IPv4 header (%zd)"), packet->len, ether_size + ip_size + todo);
+               return;
+       }
+
+       ifdebug(TRAFFIC) logger(LOG_INFO, _("Fragmenting packet of %d bytes to %s (%s)"), packet->len, dest->name, dest->hostname);
+
+       offset = packet->data + ether_size + ip_size;
+       maxlen = (dest->mtu - ether_size - ip_size) & ~0x7;
+       ip_off = ntohs(ip.ip_off);
+       origf = ip_off & ~IP_OFFMASK;
+       ip_off &= IP_OFFMASK;
+       
+       while(todo) {
+               len = todo > maxlen ? maxlen : todo;
+               memcpy(fragment.data + ether_size + ip_size, offset, len);
+               todo -= len;
+               offset += len;
+
+               ip.ip_len = htons(ip_size + len);
+               ip.ip_off = htons(ip_off | origf | (todo ? IP_MF : 0));
+               ip.ip_sum = 0;
+               ip.ip_sum = inet_checksum(&ip, ip_size, ~0);
+               memcpy(fragment.data, packet->data, ether_size);
+               memcpy(fragment.data + ether_size, &ip, ip_size);
+               fragment.len = ether_size + ip_size + len;
+
+               send_packet(dest, &fragment);
+
+               ip_off += len / 8;
+       }       
+}
+
+static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet)
 {
        subnet_t *subnet;
+       node_t *via;
+       ipv4_t dest;
 
        cp();
 
-       subnet = lookup_subnet_ipv4((ipv4_t *) &packet->data[30]);
+       memcpy(&dest, &packet->data[30], sizeof dest);
+       subnet = lookup_subnet_ipv4(&dest);
 
        if(!subnet) {
                ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet from %s (%s): unknown IPv4 destination address %d.%d.%d.%d"),
                                source->name, source->hostname,
-                               packet->data[30],
-                               packet->data[31],
-                               packet->data[32],
-                               packet->data[33]);
+                               dest.x[0],
+                               dest.x[1],
+                               dest.x[2],
+                               dest.x[3]);
 
                route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNKNOWN);
                return;
@@ -304,27 +349,41 @@ static __inline__ void route_ipv4_unicast(node_t *source, vpn_packet_t *packet)
        if(!subnet->owner->status.reachable)
                route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
 
-       if(subnet->owner->options & OPTION_PMTU_DISCOVERY && packet->len > subnet->owner->mtu && subnet->owner != myself) {
-               ifdebug(TRAFFIC) logger(LOG_INFO, _("Packet for %s (%s) length %d larger than MTU %d"), subnet->owner->name, subnet->owner->hostname, packet->len, subnet->owner->mtu);
-               packet->len = subnet->owner->mtu;
-               route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
-               return;
-       }
-
        if(priorityinheritance)
                packet->priority = packet->data[15];
 
+       via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
+       
+       if(via && packet->len > via->mtu && via != myself) {
+               ifdebug(TRAFFIC) logger(LOG_INFO, _("Packet for %s (%s) length %d larger than MTU %d"), subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
+               if(packet->data[20] & 0x40) {
+                       packet->len = via->mtu;
+                       route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
+               } else {
+                       fragment_ipv4_packet(via, packet);
+               }
+
+               return;
+       }
+
        send_packet(subnet->owner, packet);
 }
 
-static __inline__ void route_ipv4(node_t *source, vpn_packet_t *packet)
+static void route_ipv4(node_t *source, vpn_packet_t *packet)
 {
        cp();
 
        if(!checklength(source, packet, ether_size + ip_size))
                return;
 
-       route_ipv4_unicast(source, packet);
+       if(packet->data[30] & 0xf0 == 0xe0 ||
+                       packet->data[30] == 255 &&
+                       packet->data[31] == 255 &&
+                       packet->data[32] == 255 &&
+                       packet->data[33] == 255)
+               broadcast_packet(source, packet);
+       else
+               route_ipv4_unicast(source, packet);
 }
 
 /* RFC 2463 */
@@ -406,25 +465,28 @@ static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
        send_packet(source, packet);
 }
 
-static __inline__ void route_ipv6_unicast(node_t *source, vpn_packet_t *packet)
+static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet)
 {
        subnet_t *subnet;
+       node_t *via;
+       ipv6_t dest;
 
        cp();
 
-       subnet = lookup_subnet_ipv6((ipv6_t *) &packet->data[38]);
+       memcpy(&dest, &packet->data[38], sizeof dest);
+       subnet = lookup_subnet_ipv6(&dest);
 
        if(!subnet) {
                ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet from %s (%s): unknown IPv6 destination address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
                                source->name, source->hostname,
-                               ntohs(*(uint16_t *) &packet->data[38]),
-                               ntohs(*(uint16_t *) &packet->data[40]),
-                               ntohs(*(uint16_t *) &packet->data[42]),
-                               ntohs(*(uint16_t *) &packet->data[44]),
-                               ntohs(*(uint16_t *) &packet->data[46]),
-                               ntohs(*(uint16_t *) &packet->data[48]),
-                               ntohs(*(uint16_t *) &packet->data[50]),
-                               ntohs(*(uint16_t *) &packet->data[52]));
+                               ntohs(dest.x[0]),
+                               ntohs(dest.x[1]),
+                               ntohs(dest.x[2]),
+                               ntohs(dest.x[3]),
+                               ntohs(dest.x[4]),
+                               ntohs(dest.x[5]),
+                               ntohs(dest.x[6]),
+                               ntohs(dest.x[7]));
 
                route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR);
                return;
@@ -437,10 +499,12 @@ static __inline__ void route_ipv6_unicast(node_t *source, vpn_packet_t *packet)
 
        if(!subnet->owner->status.reachable)
                route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+
+       via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
        
-       if(subnet->owner->options & OPTION_PMTU_DISCOVERY && packet->len > subnet->owner->mtu && subnet->owner != myself) {
-               ifdebug(TRAFFIC) logger(LOG_INFO, _("Packet for %s (%s) length %d larger than MTU %d"), subnet->owner->name, subnet->owner->hostname, packet->len, subnet->owner->mtu);
-               packet->len = subnet->owner->mtu;
+       if(via && packet->len > via->mtu && via != myself) {
+               ifdebug(TRAFFIC) logger(LOG_INFO, _("Packet for %s (%s) length %d larger than MTU %d"), subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
+               packet->len = via->mtu;
                route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
                return;
        }
@@ -576,7 +640,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet)
        send_packet(source, packet);
 }
 
-static __inline__ void route_ipv6(node_t *source, vpn_packet_t *packet)
+static void route_ipv6(node_t *source, vpn_packet_t *packet)
 {
        cp();
 
@@ -588,7 +652,10 @@ static __inline__ void route_ipv6(node_t *source, vpn_packet_t *packet)
                return;
        }
 
-       route_ipv6_unicast(source, packet);
+       if(packet->data[38] == 255)
+               broadcast_packet(source, packet);
+       else
+               route_ipv6_unicast(source, packet);
 }
 
 /* RFC 826 */