+/* RFC 2463 */
+
+static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t type, uint8_t code) {
+ struct ip6_hdr ip6;
+ struct icmp6_hdr icmp6 = {0};
+ 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(3))
+ return;
+
+ /* Swap Ethernet source and destination addresses */
+
+ swap_mac_addresses(packet);
+
+ /* Copy headers from packet to structs on the stack */
+
+ memcpy(&ip6, packet->data + ether_size, ip6_size);
+
+ /* Remember original source and destination */
+
+ pseudo.ip6_src = ip6.ip6_dst;
+ pseudo.ip6_dst = ip6.ip6_src;
+
+ pseudo.length = packet->len - ether_size;
+
+ if(type == ICMP6_PACKET_TOO_BIG)
+ icmp6.icmp6_mtu = htonl(pseudo.length);
+
+ if(pseudo.length >= IP_MSS - ip6_size - icmp6_size)
+ pseudo.length = IP_MSS - ip6_size - icmp6_size;
+
+ /* Copy first part of original contents to ICMP message */
+
+ memmove(packet->data + ether_size + ip6_size + icmp6_size, packet->data + ether_size, pseudo.length);
+
+ /* Fill in IPv6 header */
+
+ ip6.ip6_flow = htonl(0x60000000UL);
+ ip6.ip6_plen = htons(icmp6_size + pseudo.length);
+ ip6.ip6_nxt = IPPROTO_ICMPV6;
+ ip6.ip6_hlim = 255;
+ ip6.ip6_src = pseudo.ip6_src;
+ ip6.ip6_dst = pseudo.ip6_dst;
+
+ /* Fill in ICMP header */
+
+ icmp6.icmp6_type = type;
+ icmp6.icmp6_code = code;
+ icmp6.icmp6_cksum = 0;
+
+ /* Create pseudo header */
+
+ pseudo.length = htonl(icmp6_size + pseudo.length);
+ pseudo.next = htonl(IPPROTO_ICMPV6);
+
+ /* Generate checksum */
+
+ checksum = inet_checksum(&pseudo, sizeof pseudo, ~0);
+ checksum = inet_checksum(&icmp6, icmp6_size, checksum);
+ checksum = inet_checksum(packet->data + ether_size + ip6_size + icmp6_size, ntohl(pseudo.length) - icmp6_size, checksum);
+
+ icmp6.icmp6_cksum = checksum;
+
+ /* Copy structs on stack back to packet */
+
+ memcpy(packet->data + ether_size, &ip6, ip6_size);
+ memcpy(packet->data + ether_size + ip6_size, &icmp6, icmp6_size);
+
+ packet->len = ether_size + ip6_size + ntohl(pseudo.length);
+
+ send_packet(source, packet);
+}
+
+static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
+ subnet_t *subnet;
+ node_t *via;
+ ipv6_t dest;
+
+ 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(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;
+ }
+
+ if(subnet->owner == source) {
+ ifdebug(TRAFFIC) logger(LOG_WARNING, "Packet looping back to %s (%s)!", source->name, source->hostname);
+ return;
+ }