Roopa Prabhu 97a907c5fe Fix mstp settings ordering issues when bridge stp is toggled on and off ...

(when mstp settings are specified under the port)

Ticket: CM-6626
Reviewed By: CCR-3599
Testing Done: Tested the problem case mentioned in the bug (Plan to
re-work the fix a bit for 2.5.5)

problem:
    mstp parameters can be specified under the port or under the bridge
    When they are specified under the bridge, there should be no problem
(When you process the bridge, all things on the bridge port are set in
order)
    When they are specified under the port:
    we check if the bridge is up, if yes, and stp is already configured,
we process mstpctl settings
    This check today only checks running stp_state
    We should also check the user configured stp state for the bridge
    Note that the problem exists only if the bridge and ports are
already up and user executes ifup again and when we need to re-evaluate
the bridge port settings

solution:
    When the bridge port is being checked for mstp settings, not only
check running stp state, but also check user specified stp state and
correct bridge stp state before proceeding with mstp configuration

Few things to note with this patch:
    - If user changed stp state on bridge to 'on', and did `ifup
    <bridge_port>'`,
    though the user has not ifup'ed the bridge yet, the bridge stp state
    will be applied (very few people will run into this and practically this
    should not be a problem atall. But from correctness POV it is
    a voilation. ).

    - To avoid this, the other solution would have been to let the bridge
    port code be as is, but handle this during bringing up the bridge,
    but, this can confuse the user, because when processing the
    bridge_port, you will still throw warnings even if the port stp config
    is later reapplied when the bridge comes up

    - note that the patch only handles the case when stp state is not on and
    somebody turned it on.  For the case where stp state was on and somebody
    turned it off, this patch wont throw warnings for the mstpctl config. But
    it will not cause any issues because once stp is off things will be ok
    everywhere. I want to keep any changes here out of this patch. I will
    document this in the bug...and see if i can handle this in 2.5.5

2015-09-29 10:22:58 -07:00

36 KiB

Raw Blame History

View Raw