Prevent the attachment of a subnet to a router

[Mathieu Rohon]

Some external plugins might need to prevent the attachment of a subnet to a router, like reported in bug [1]

Now that [2] has been fixed, we can prevent this attachment by adding a new BEFORE_UPDATE callback in ML2, which will be triggered when the router port gets updated by the l3plugin.
Raising an exception during the processing of the BEFORE_UPDATE call should result in preventing the attachment of the subnet to the router.

[1]https://bugs.launchpad.net/bgpvpn/+bug/1537067
[2]https://bugs.launchpad.net/bgpvpn/+bug/1475093

[Armando Migliaccio (armando-migliaccio)]

If all you need is a callback hook, this does not need an RFE. Hooks are generally accepted as a way to integrate loosely the various components that make up Neutron. We only need to make sure we add it in the right place. Feel free to proceed as a regular bug fix.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/369221

[Mathieu Rohon (mathieu-rohon)]

This patch is needed to fix a high priority bug in networking-bgpvpn :

https://bugs.launchpad.net/bgpvpn/+bug/1537067

The code seems ready and not disturbing, I hope it will get merged in a RC!

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/369221
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=71dd840d30130afad37d8c1f404d7167a2063a8d
Submitter: Jenkins
Branch: master

commit 71dd840d30130afad37d8c1f404d7167a2063a8d
Author: Mathieu Rohon <email address hidden>
Date: Mon Sep 12 07:58:00 2016 +0000

    Send a callback before attaching a subnet to a router

    Attaching a subnet to a router may be forbidden in some cases.
    To prevent this attachment, we need to send a BEFORE_CREATE event
    with "router_interface" as resource, and reraise any exception
    that tells neutron a third party code forbid this attachment.

    Change-Id: Ia71e0c5e9e3e073053ead7e1e7c3040087f5ee13
    Closes-bug: 1537091

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/newton
Review: https://review.openstack.org/377090

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/377090
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=27e6ba09327c429e5c2ccb90d0d0169bed75a450
Submitter: Jenkins
Branch: stable/newton

commit 27e6ba09327c429e5c2ccb90d0d0169bed75a450
Author: Mathieu Rohon <email address hidden>
Date: Mon Sep 12 07:58:00 2016 +0000

    Send a callback before attaching a subnet to a router

    Attaching a subnet to a router may be forbidden in some cases.
    To prevent this attachment, we need to send a BEFORE_CREATE event
    with "router_interface" as resource, and reraise any exception
    that tells neutron a third party code forbid this attachment.

    Change-Id: Ia71e0c5e9e3e073053ead7e1e7c3040087f5ee13
    Closes-bug: 1537091
    (cherry picked from commit 71dd840d30130afad37d8c1f404d7167a2063a8d)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 9.0.0.0rc2 release candidate.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 10.0.0.0b1 development milestone.