icmpv6_is_err
if (!icmpv6_is_err(fk->icmp.type))
if (icmpv6_is_err(icmp6h->icmp6_type) ||
if (!icmpv6_is_err(icmp6_hdr(skb)->icmp6_type))
if (!icmpv6_is_err(icmph->icmp6_type))