fr_nat_ioctl
error = fr_nat_ioctl(data, cmd, mode, uid, NULL, ifs);
error = fr_nat_ioctl(data, cmd, mode, uid, ctx, ifs);
if (fr_nat_ioctl((caddr_t)ipn, SIOCRMNAT, NAT_SYSSPACE|
if (fr_nat_ioctl((caddr_t)ipn, SIOCADNAT,
extern int fr_nat_ioctl __P((caddr_t, ioctlcmd_t, int, int, void *, ipf_stack_t *));