ip6_tnl_err
err = ip6_tnl_err(skb, IPPROTO_IPIP, opt, &rel_type, &rel_code,
err = ip6_tnl_err(skb, IPPROTO_IPV6, opt, &rel_type, &rel_code,
err = ip6_tnl_err(skb, IPPROTO_MPLS, opt, &rel_type, &rel_code,