nat64_icmp6_reflect
nat64_icmp6_reflect(m, ICMP6_TIME_EXCEEDED,
nat64_icmp6_reflect(m, ICMP6_PARAM_PROB,
nat64_icmp6_reflect(m, ICMP6_DST_UNREACH,
nat64_icmp6_reflect(m, ICMP6_PACKET_TOO_BIG, 0, nh->nh_mtu,