nat_delete
if (nat_delete((nat_t *)ent, NL_FLUSH, ifs) == 0)
(nat_delete(nat, NL_EXPIRE, ifs) == 0))
(void) nat_delete(tqe->tqe_parent, NL_EXPIRE, ifs);
(void) nat_delete(tqe->tqe_parent, NL_EXPIRE, ifs);
(void) nat_delete(nat, NL_EXPIRE, ifs);
if (nat_delete(nat, NL_FLUSH, ifs) == 0)
(void) nat_delete(nat, NL_DESTROY, ifs);
extern int nat_delete __P((struct nat *, int, ipf_stack_t *));