+ cp();
+
+ if(!checklength(source, packet, ether_size + ip6_size))
+ return;
+
+ if(packet->data[20] == IPPROTO_ICMPV6 && checklength(source, packet, ether_size + ip6_size + icmp6_size) && packet->data[54] == ND_NEIGHBOR_SOLICIT) {
+ route_neighborsol(source, packet);
+ return;
+ }
+
+ if(packet->data[38] == 255)
+ broadcast_packet(source, packet);
+ else
+ route_ipv6_unicast(source, packet);
+}
+
+/* RFC 826 */
+
+static void route_arp(node_t *source, vpn_packet_t *packet)
+{
+ struct ether_arp arp;
+ subnet_t *subnet;
+ struct in_addr addr;
+
+ cp();
+
+ if(!checklength(source, packet, ether_size + arp_size))
+ return;
+
+ if(source != myself) {
+ ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got ARP request from %s (%s) while in router mode!"), source->name, source->hostname);
+ return;
+ }
+
+ /* First, snatch the source address from the ARP packet */
+
+ if(overwrite_mac)
+ memcpy(mymac.x, packet->data + ETH_ALEN, ETH_ALEN);
+
+ /* Copy headers from packet to structs on the stack */
+
+ memcpy(&arp, packet->data + ether_size, arp_size);
+
+ /* Check if this is a valid ARP request */
+
+ if(ntohs(arp.arp_hrd) != ARPHRD_ETHER || ntohs(arp.arp_pro) != ETH_P_IP ||
+ arp.arp_hln != ETH_ALEN || arp.arp_pln != sizeof(addr) || ntohs(arp.arp_op) != ARPOP_REQUEST) {
+ ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type ARP request"));
+ return;
+ }
+
+ /* Check if the IPv4 address exists on the VPN */
+
+ subnet = lookup_subnet_ipv4((ipv4_t *) &arp.arp_tpa);
+
+ if(!subnet) {
+ ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: ARP request for unknown address %d.%d.%d.%d"),
+ arp.arp_tpa[0], arp.arp_tpa[1], arp.arp_tpa[2],
+ arp.arp_tpa[3]);
+ return;
+ }
+
+ /* Check if it is for our own subnet */
+
+ if(subnet->owner == myself)
+ return; /* silently ignore */
+
+ memcpy(packet->data, packet->data + ETH_ALEN, ETH_ALEN); /* copy destination address */
+ packet->data[ETH_ALEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */
+
+ memcpy(&addr, arp.arp_tpa, sizeof(addr)); /* save protocol addr */
+ memcpy(arp.arp_tpa, arp.arp_spa, sizeof(addr)); /* swap destination and source protocol address */
+ memcpy(arp.arp_spa, &addr, sizeof(addr)); /* ... */
+
+ memcpy(arp.arp_tha, arp.arp_sha, ETH_ALEN); /* set target hard/proto addr */
+ memcpy(arp.arp_sha, packet->data + ETH_ALEN, ETH_ALEN); /* add fake source hard addr */
+ arp.arp_op = htons(ARPOP_REPLY);
+
+ /* Copy structs on stack back to packet */
+
+ memcpy(packet->data + ether_size, &arp, arp_size);
+
+ send_packet(source, 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) {
+ mac_t src;
+ memcpy(&src, &packet->data[6], sizeof src);
+ learn_mac(&src);
+ }
+
+ /* Lookup destination address */
+
+ memcpy(&dest, &packet->data[0], sizeof dest);
+ subnet = lookup_subnet_mac(&dest);
+
+ if(!subnet) {
+ broadcast_packet(source, packet);
+ return;
+ }
+
+ if(subnet->owner == source) {
+ ifdebug(TRAFFIC) logger(LOG_WARNING, _("Packet looping back to %s (%s)!"), source->name, source->hostname);
+ return;
+ }
+
+ // Handle packets larger than PMTU
+
+ node_t *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);
+ uint16_t type = packet->data[12] << 8 | packet->data[13];
+ if(type == ETH_P_IP) {
+ 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);
+ }
+ } else if(type == ETH_P_IPV6) {
+ packet->len = via->mtu;
+ route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
+ } else
+ ifdebug(TRAFFIC) logger(LOG_INFO, _("Large packet of unhandled type %hx dropped"), type);
+
+ return;
+ }
+
+ send_packet(subnet->owner, packet);
+}
+
+
+void route(node_t *source, vpn_packet_t *packet)
+{
+ cp();
+
+ if(!checklength(source, packet, ether_size))
+ return;
+
+ switch (routing_mode) {
+ case RMODE_ROUTER:
+ {
+ uint16_t type = packet->data[12] << 8 | packet->data[13];
+
+ switch (type) {
+ case ETH_P_ARP:
+ route_arp(source, packet);
+ break;
+
+ case ETH_P_IP:
+ route_ipv4(source, packet);
+ break;
+
+ case ETH_P_IPV6:
+ route_ipv6(source, packet);
+ break;
+
+ default:
+ ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet from %s (%s): unknown type %hx"), source->name, source->hostname, type);
+ break;
+ }
+ }
+ break;
+
+ case RMODE_SWITCH:
+ route_mac(source, packet);
+ break;
+
+ case RMODE_HUB:
+ broadcast_packet(source, packet);
+ break;
+ }