pf_state_expires
pf_state_expires(const struct pf_kstate *);
if (pf_state_expires(s) <= time_uptime) {
sp->pfs_1301.expire = pf_state_expires(st);
sp->expire = pf_state_expires(st);
uint32_t expire = pf_state_expires(s);
expire = pf_state_expires(s);