ipf_nat6_icmperror
extern nat_t *ipf_nat6_icmperror(fr_info_t *, u_int *, int);
(nat = ipf_nat6_icmperror(fin, &nflags, NAT_OUTBOUND)))
(nat = ipf_nat6_icmperror(fin, &nflags, NAT_INBOUND)))