ip6t_npt_map_pfx
if (!ip6t_npt_map_pfx(npt, &ipv6_hdr(skb)->saddr)) {
ip6t_npt_map_pfx(npt, &bounced_hdr->daddr);
if (!ip6t_npt_map_pfx(npt, &ipv6_hdr(skb)->daddr)) {
ip6t_npt_map_pfx(npt, &bounced_hdr->saddr);