+static int ip6_forward_proxy_check(struct sk_buff *skb)
+{
+ struct ipv6hdr *hdr = ipv6_hdr(skb);
+ u8 nexthdr = hdr->nexthdr;
+ int offset;
+
+ if (ipv6_ext_hdr(nexthdr)) {
+ offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr);
+ if (offset < 0)
+ return 0;
+ } else
+ offset = sizeof(struct ipv6hdr);
+
+ if (nexthdr == IPPROTO_ICMPV6) {
+ struct icmp6hdr *icmp6;
+
+ if (!pskb_may_pull(skb, (skb_network_header(skb) +
+ offset + 1 - skb->data)))
+ return 0;
+
+ icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
+
+ switch (icmp6->icmp6_type) {
+ case NDISC_ROUTER_SOLICITATION:
+ case NDISC_ROUTER_ADVERTISEMENT:
+ case NDISC_NEIGHBOUR_SOLICITATION:
+ case NDISC_NEIGHBOUR_ADVERTISEMENT:
+ case NDISC_REDIRECT:
+ /* For reaction involving unicast neighbor discovery
+ * message destined to the proxied address, pass it to
+ * input function.
+ */
+ return 1;
+ default:
+ break;
+ }
+ }
+
+ /*
+ * The proxying router can't forward traffic sent to a link-local
+ * address, so signal the sender and discard the packet. This
+ * behavior is clarified by the MIPv6 specification.
+ */
+ if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
+ dst_link_failure(skb);
+ return -1;
+ }
+
+ return 0;
+}
+