Function pfsync_upd_tcp

freebsd/netpfil/pf/if_pfsync.c:864–896

}

static int
pfsync_upd_tcp(struct pf_state *st, struct pfsync_state_peer *src,
    struct pfsync_state_peer *dst)
{
	int sync = 0;

	PF_STATE_LOCK_ASSERT(st);

	/*
	 * The state should never go backwards except
	 * for syn-proxy states.  Neither should the
	 * sequence window slide backwards.
	 */
	if ((st->src.state > src->state &&
	    (st->src.state < PF_TCPS_PROXY_SRC ||
	    src->state >= PF_TCPS_PROXY_SRC)) ||

	    (st->src.state == src->state &&
	    SEQ_GT(st->src.seqlo, ntohl(src->seqlo))))
		sync++;
	else
		pf_state_peer_ntoh(src, &st->src);

	if ((st->dst.state > dst->state) ||

	    (st->dst.state >= TCPS_SYN_SENT &&
	    SEQ_GT(st->dst.seqlo, ntohl(dst->seqlo))))
		sync++;
	else
		pf_state_peer_ntoh(dst, &st->dst);

	return (sync);
}

static int
pfsync_in_upd(struct pfsync_pkt *pkt, struct mbuf *m, int offset, int count)