static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
				  int bearer_id, struct sk_buff_head *xmitq)
{
	struct tipc_msg *hdr = buf_msg(skb);
	int usr = msg_user(hdr);
	int mtyp = msg_type(hdr);
	u16 oseqno = msg_seqno(hdr);
	u16 exp_pkts = msg_msgcnt(hdr);
	u16 rcv_nxt, syncpt, dlv_nxt, inputq_len;
	int state = n->state;
	struct tipc_link *l, *tnl, *pl = NULL;
	struct tipc_media_addr *maddr;
	int pb_id;

	if (trace_tipc_node_check_state_enabled()) {
		trace_tipc_skb_dump(skb, false, "skb for node state check");
		trace_tipc_node_check_state(n, true, " ");
	}
	l = n->links[bearer_id].link;
	if (!l)
		return false;
	rcv_nxt = tipc_link_rcv_nxt(l);


	if (likely((state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL)))
		return true;

	/* Find parallel link, if any */
	for (pb_id = 0; pb_id < MAX_BEARERS; pb_id++) {
		if ((pb_id != bearer_id) && n->links[pb_id].link) {
			pl = n->links[pb_id].link;
			break;
		}
	}

	if (!tipc_link_validate_msg(l, hdr)) {
		trace_tipc_skb_dump(skb, false, "PROTO invalid (2)!");
		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (2)!");
		return false;
	}

	/* Check and update node accesibility if applicable */
	if (state == SELF_UP_PEER_COMING) {
		if (!tipc_link_is_up(l))
			return true;
		if (!msg_peer_link_is_up(hdr))
			return true;
		tipc_node_fsm_evt(n, PEER_ESTABL_CONTACT_EVT);
	}

	if (state == SELF_DOWN_PEER_LEAVING) {
		if (msg_peer_node_is_up(hdr))
			return false;
		tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
		return true;
	}

	if (state == SELF_LEAVING_PEER_DOWN)
		return false;

	/* Ignore duplicate packets */
	if ((usr != LINK_PROTOCOL) && less(oseqno, rcv_nxt))
		return true;

	/* Initiate or update failover mode if applicable */
	if ((usr == TUNNEL_PROTOCOL) && (mtyp == FAILOVER_MSG)) {
		syncpt = oseqno + exp_pkts - 1;
		if (pl && !tipc_link_is_reset(pl)) {
			__tipc_node_link_down(n, &pb_id, xmitq, &maddr);
			trace_tipc_node_link_down(n, true,
						  "node link down <- failover!");
			tipc_skb_queue_splice_tail_init(tipc_link_inputq(pl),
							tipc_link_inputq(l));
		}

		/* If parallel link was already down, and this happened before
		 * the tunnel link came up, node failover was never started.
		 * Ensure that a FAILOVER_MSG is sent to get peer out of
		 * NODE_FAILINGOVER state, also this node must accept
		 * TUNNEL_MSGs from peer.
		 */
		if (n->state != NODE_FAILINGOVER)
			tipc_node_link_failover(n, pl, l, xmitq);

		/* If pkts arrive out of order, use lowest calculated syncpt */
		if (less(syncpt, n->sync_point))
			n->sync_point = syncpt;
	}

	/* Open parallel link when tunnel link reaches synch point */
	if ((n->state == NODE_FAILINGOVER) && tipc_link_is_up(l)) {
		if (!more(rcv_nxt, n->sync_point))
			return true;
		tipc_node_fsm_evt(n, NODE_FAILOVER_END_EVT);
		if (pl)
			tipc_link_fsm_evt(pl, LINK_FAILOVER_END_EVT);
		return true;
	}

	/* No synching needed if only one link */
	if (!pl || !tipc_link_is_up(pl))
		return true;

	/* Initiate synch mode if applicable */
	if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG) && (oseqno == 1)) {
		if (n->capabilities & TIPC_TUNNEL_ENHANCED)
			syncpt = msg_syncpt(hdr);
		else
			syncpt = msg_seqno(msg_inner_hdr(hdr)) + exp_pkts - 1;
		if (!tipc_link_is_up(l))
			__tipc_node_link_up(n, bearer_id, xmitq);
		if (n->state == SELF_UP_PEER_UP) {
			n->sync_point = syncpt;
			tipc_link_fsm_evt(l, LINK_SYNCH_BEGIN_EVT);
			tipc_node_fsm_evt(n, NODE_SYNCH_BEGIN_EVT);
		}
	}

	/* Open tunnel link when parallel link reaches synch point */
	if (n->state == NODE_SYNCHING) {
		if (tipc_link_is_synching(l)) {
			tnl = l;
		} else {
			tnl = pl;
			pl = l;
		}
		inputq_len = skb_queue_len(tipc_link_inputq(pl));
		dlv_nxt = tipc_link_rcv_nxt(pl) - inputq_len;
		if (more(dlv_nxt, n->sync_point)) {
			tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
			tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
			return true;
		}
		if (l == pl)
			return true;
		if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG))
			return true;
		if (usr == LINK_PROTOCOL)
			return true;
		return false;
	}
	return true;
}