+ checksum = inet_checksum((uint16_t *)&pseudo, sizeof(pseudo)/2, ~0);
+ checksum = inet_checksum((uint16_t *)ns, sizeof(*ns)/2 + 4, checksum);
+
+ if(checksum)
+ {
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ syslog(LOG_WARNING, _("Cannot route packet: checksum error for neighbor solicitation request"));
+ return;
+ }
+
+ /* Check if the IPv6 address exists on the VPN */
+
+ subnet = lookup_subnet_ipv6((ipv6_t *)&ns->nd_ns_target);
+
+ if(!subnet)
+ {
+ if(debug_lvl >= DEBUG_TRAFFIC)
+ {
+ syslog(LOG_WARNING, _("Cannot route packet: neighbor solicitation request for unknown address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
+ ntohs(((uint16_t *)&ns->nd_ns_target)[0]), ntohs(((uint16_t *)&ns->nd_ns_target)[1]), ntohs(((uint16_t *)&ns->nd_ns_target)[2]), ntohs(((uint16_t *)&ns->nd_ns_target)[3]),
+ ntohs(((uint16_t *)&ns->nd_ns_target)[4]), ntohs(((uint16_t *)&ns->nd_ns_target)[5]), ntohs(((uint16_t *)&ns->nd_ns_target)[6]), ntohs(((uint16_t *)&ns->nd_ns_target)[7]));
+ }
+
+ return;
+ }
+
+ /* Check if it is for our own subnet */
+
+ if(subnet->owner == myself)
+ return; /* silently ignore */
+
+ /* Create neighbor advertation reply */
+
+ memcpy(packet->data, packet->data + ETHER_ADDR_LEN, ETHER_ADDR_LEN); /* copy destination address */
+ packet->data[ETHER_ADDR_LEN*2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */
+
+ memcpy(&hdr->ip6_dst, &hdr->ip6_src, 16); /* swap destination and source protocol address */
+ memcpy(&hdr->ip6_src, &ns->nd_ns_target, 16); /* ... */
+
+ memcpy((char *)opt + sizeof(*opt), packet->data + ETHER_ADDR_LEN, 6); /* add fake source hard addr */
+
+ ns->nd_ns_hdr.icmp6_cksum = 0;
+ ns->nd_ns_hdr.icmp6_type = ND_NEIGHBOR_ADVERT;
+ ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[0] = 0x40; /* Set solicited flag */
+ ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[1] = ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[2] = ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[3] = 0;
+ opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
+
+ /* Create pseudo header */
+
+ memcpy(&pseudo.ip6_src, &hdr->ip6_src, 16);
+ memcpy(&pseudo.ip6_dst, &hdr->ip6_dst, 16);
+ pseudo.length = htonl(sizeof(*ns) + sizeof(*opt) + 6);
+ pseudo.junk[0] = pseudo.junk[1] = pseudo.junk[2] = 0;
+ pseudo.junk[3] = IPPROTO_ICMPV6;
+
+ /* Generate checksum */
+
+ checksum = inet_checksum((uint16_t *)&pseudo, sizeof(pseudo)/2, ~0);
+ checksum = inet_checksum((uint16_t *)ns, sizeof(*ns)/2 + 4, checksum);
+
+ ns->nd_ns_hdr.icmp6_cksum = htons(checksum);
+
+ write_packet(packet);