- cp();
-
- /* Learn source address */
-
- learn_mac((mac_t *)(&packet->data[6]));
-
- /* Lookup destination address */
-
- subnet = lookup_subnet_mac((mac_t *)(&packet->data[0]));
-
- if(subnet)
- return subnet->owner;
- else
- return NULL;
-}
-
-/* RFC 792 */
-
-static void route_ipv4_unreachable(vpn_packet_t *packet, uint8_t code)
-{
- struct ip *hdr;
- struct icmp *icmp;
-
- struct in_addr ip_src;
- struct in_addr ip_dst;
- uint32_t oldlen;
-
- if(ratelimit())
- return;
-
- cp();
-
- hdr = (struct ip *)(packet->data + 14);
- icmp = (struct icmp *)(packet->data + 14 + 20);
-
- /* Remember original source and destination */
-
- memcpy(&ip_src, &hdr->ip_src, 4);
- memcpy(&ip_dst, &hdr->ip_dst, 4);
- oldlen = packet->len - 14;
-
- if(oldlen >= IP_MSS - sizeof(*hdr) - sizeof(*icmp))
- oldlen = IP_MSS - sizeof(*hdr) - sizeof(*icmp);
-
- /* Copy first part of original contents to ICMP message */
-
- memmove(&icmp->icmp_ip, hdr, oldlen);
-
- /* Fill in IPv4 header */
-
- hdr->ip_v = 4;
- hdr->ip_hl = sizeof(*hdr) / 4;
- hdr->ip_tos = 0;
- hdr->ip_len = htons(20 + 8 + oldlen);
- hdr->ip_id = 0;
- hdr->ip_off = 0;
- hdr->ip_ttl = 255;
- hdr->ip_p = IPPROTO_ICMP;
- hdr->ip_sum = 0;
- memcpy(&hdr->ip_src, &ip_dst, 4);
- memcpy(&hdr->ip_dst, &ip_src, 4);
-
- hdr->ip_sum = inet_checksum(hdr, 20, ~0);
-
- /* Fill in ICMP header */
-
- icmp->icmp_type = ICMP_DEST_UNREACH;
- icmp->icmp_code = code;
- icmp->icmp_cksum = 0;
-
- icmp->icmp_cksum = inet_checksum(icmp, 8 + oldlen, ~0);
-
- packet->len = 14 + 20 + 8 + oldlen;
-
- write_packet(packet);
-}
-
-static node_t *route_ipv4(vpn_packet_t *packet)
-{
- subnet_t *subnet;
-
- cp();
-
- if(priorityinheritance)
- packet->priority = packet->data[15];
-
- subnet = lookup_subnet_ipv4((ipv4_t *) & packet->data[30]);
-
- if(!subnet) {
- ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: unknown IPv4 destination address %d.%d.%d.%d"),
- packet->data[30], packet->data[31], packet->data[32],
- packet->data[33]);
-
- route_ipv4_unreachable(packet, ICMP_NET_UNKNOWN);
- return NULL;
- }
-
- if(!subnet->owner->status.reachable)
- route_ipv4_unreachable(packet, ICMP_NET_UNREACH);
-
- return subnet->owner;
-}
-
-/* RFC 2463 */
-
-static void route_ipv6_unreachable(vpn_packet_t *packet, uint8_t code)
-{
- struct ip6_hdr *hdr;
- struct icmp6_hdr *icmp;
- uint16_t checksum;
-
- struct {
- struct in6_addr ip6_src; /* source address */
- struct in6_addr ip6_dst; /* destination address */
- uint32_t length;
- uint32_t next;
- } pseudo;
-
- if(ratelimit())