+static int vti6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+ u8 type, u8 code, int offset, __be32 info)
+{
+ __be32 spi;
+ struct xfrm_state *x;
+ struct ip6_tnl *t;
+ struct ip_esp_hdr *esph;
+ struct ip_auth_hdr *ah;
+ struct ip_comp_hdr *ipch;
+ struct net *net = dev_net(skb->dev);
+ const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
+ int protocol = iph->nexthdr;
+
+ t = vti6_tnl_lookup(dev_net(skb->dev), &iph->daddr, &iph->saddr);
+ if (!t)
+ return -1;
+
+ switch (protocol) {
+ case IPPROTO_ESP:
+ esph = (struct ip_esp_hdr *)(skb->data + offset);
+ spi = esph->spi;
+ break;
+ case IPPROTO_AH:
+ ah = (struct ip_auth_hdr *)(skb->data + offset);
+ spi = ah->spi;
+ break;
+ case IPPROTO_COMP:
+ ipch = (struct ip_comp_hdr *)(skb->data + offset);
+ spi = htonl(ntohs(ipch->cpi));
+ break;
+ default:
+ return 0;
+ }
+
+ if (type != ICMPV6_PKT_TOOBIG &&
+ type != NDISC_REDIRECT)
+ return 0;
+
+ x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
+ spi, protocol, AF_INET6);
+ if (!x)
+ return 0;
+
+ if (type == NDISC_REDIRECT)
+ ip6_redirect(skb, net, skb->dev->ifindex, 0);
+ else
+ ip6_update_pmtu(skb, net, info, 0, 0);
+ xfrm_state_put(x);
+
+ return 0;
+}
+