NAT64_ICMP6_PLEN
sizeof(struct icmp6_hdr) + len > NAT64_ICMP6_PLEN)
len = NAT64_ICMP6_PLEN - sizeof(struct icmp6_hdr) -
len = (m->m_pkthdr.len > NAT64_ICMP6_PLEN) ? NAT64_ICMP6_PLEN: