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Commit 7d04fe15 authored by Tung Nguyen's avatar Tung Nguyen Committed by Greg Kroah-Hartman
Browse files

tipc: fix unexpected link reset due to discovery messages 



[ Upstream commit c244c092f1ed2acfb5af3d3da81e22367d3dd733 ]

This unexpected behavior is observed:

node 1                    | node 2
------                    | ------
link is established       | link is established
reboot                    | link is reset
up                        | send discovery message
receive discovery message |
link is established       | link is established
send discovery message    |
                          | receive discovery message
                          | link is reset (unexpected)
                          | send reset message
link is reset             |

It is due to delayed re-discovery as described in function
tipc_node_check_dest(): "this link endpoint has already reset
and re-established contact with the peer, before receiving a
discovery message from that node."

However, commit 598411d7 has changed the condition for calling
tipc_node_link_down() which was the acceptance of new media address.

This commit fixes this by restoring the old and correct behavior.

Fixes: 598411d7 ("tipc: make resetting of links non-atomic")
Acked-by: default avatarJon Maloy <jmaloy@redhat.com>
Signed-off-by: default avatarTung Nguyen <tung.q.nguyen@dektech.com.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 95b2d488

net/tipc/node.c

+8 −4
Original line number Diff line number Diff line
@@ -1035,8 +1035,9 @@ void tipc_node_check_dest(struct net *net, u32 addr, 
	bool addr_match = false;

	bool sign_match = false;

	bool link_up = false;

	bool link_is_reset = false;

	bool accept_addr = false;

	bool reset = true;

	bool reset = false;

	char *if_name;

	unsigned long intv;

	u16 session;
@@ -1056,14 +1057,14 @@ void tipc_node_check_dest(struct net *net, u32 addr, 
	/* Prepare to validate requesting node's signature and media address */

	l = le->link;

	link_up = l && tipc_link_is_up(l);

	link_is_reset = l && tipc_link_is_reset(l);

	addr_match = l && !memcmp(&le->maddr, maddr, sizeof(*maddr));

	sign_match = (signature == n->signature);



	/* These three flags give us eight permutations: */



	if (sign_match && addr_match && link_up) {

		/* All is fine. Do nothing. */

		reset = false;

		/* All is fine. Ignore requests. */

		/* Peer node is not a container/local namespace */

		if (!n->peer_hash_mix)

			n->peer_hash_mix = hash_mixes;
@@ -1088,6 +1089,7 @@ void tipc_node_check_dest(struct net *net, u32 addr, 
		 */

		accept_addr = true;

		*respond = true;

		reset = true;

	} else if (!sign_match && addr_match && link_up) {

		/* Peer node rebooted. Two possibilities:

		 *  - Delayed re-discovery; this link endpoint has already
@@ -1119,6 +1121,7 @@ void tipc_node_check_dest(struct net *net, u32 addr, 
		n->signature = signature;

		accept_addr = true;

		*respond = true;

		reset = true;

	}



	if (!accept_addr)
@@ -1147,6 +1150,7 @@ void tipc_node_check_dest(struct net *net, u32 addr, 
		tipc_link_fsm_evt(l, LINK_RESET_EVT);

		if (n->state == NODE_FAILINGOVER)

			tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);

		link_is_reset = tipc_link_is_reset(l);

		le->link = l;

		n->link_cnt++;

		tipc_node_calculate_timer(n, l);
@@ -1159,7 +1163,7 @@ void tipc_node_check_dest(struct net *net, u32 addr, 
	memcpy(&le->maddr, maddr, sizeof(*maddr));

exit:

	tipc_node_write_unlock(n);

	if (reset && l && !tipc_link_is_reset(l))

	if (reset && !link_is_reset)

		tipc_node_link_down(n, b->identity, false);

	tipc_node_put(n);

}