Re: [PATCH net 1/1] tipc: fix compatibility bug in link monitoring

[David Miller <davem@davemloft.net>]

From: Jon Maloy <jon.maloy@ericsson.com>
Date: Wed, 23 Nov 2016 21:05:26 -0500

> commit 817298102b0b ("tipc: fix link priority propagation") introduced a
> compatibility problem between TIPC versions newer than Linux 4.6 and
> those older than Linux 4.4. In versions later than 4.4, link STATE
> messages only contain a non-zero link priority value when the sender
> wants the receiver to change its priority. This has the effect that the
> receiver resets itself in order to apply the new priority. This works
> well, and is consistent with the said commit.
> 
> However, in versions older than 4.4 a valid link priority is present in
> all sent link STATE messages, leading to cyclic link establishment and
> reset on the 4.6+ node.
> 
> We fix this by adding a test that the received value should not only
> be valid, but also differ from the current value in order to cause the
> receiving link endpoint to reset.
> 
> Reported-by: Amar Nv <amar.nv005@gmail.com>
> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>

Applied.