• Jon Paul Maloy's avatar
    tipc: fix compatibility bug in link monitoring · f7967556
    Jon Paul Maloy authored
    commit 81729810 ("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: default avatarAmar Nv <amar.nv005@gmail.com>
    Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    f7967556
link.c 56.8 KB