getifname
printf("\tifp %s", getifname(nat->nat_ifps[0]));
printf(",%s ", getifname(nat->nat_ifps[1]));
PRINTF("\tinterfaces: in %s[%s", getifname(ips.is_ifp[0]),
PRINTF(",%s[%s", getifname(ips.is_ifp[1]), ips.is_ifname[1]);
PRINTF(" out %s[%s", getifname(ips.is_ifp[2]), ips.is_ifname[2]);
PRINTF(",%s[%s", getifname(ips.is_ifp[3]), ips.is_ifname[3]);
extern char *getifname __P((struct ifnet *));