Neutron does not follow the RFC 3442 spec for DHCP

[wmertens]

When metadata networking is enabled, neutron will generate a dnsmasq configuration that includes classless routes.

The RFC states that those routes should include the default route if they are defined, and that the DHCP client should ignore the default router.

This causes standards-abiding DHCP clients like dhcpcd to not provide a default gateway when running on nova.

At https://github.com/openstack/neutron/pull/22 you can see an example of how to fix this.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/96474

[Christoph Arnold (1rnold)]

Proposed fix assumes an explicitly set gateway will override a conflicting default route set via additional host routes.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/96474
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=ce59e63249dfcd86e782d056407e38e845cbe19c
Submitter: Jenkins
Branch: master

commit ce59e63249dfcd86e782d056407e38e845cbe19c
Author: Christoph Arnold <email address hidden>
Date: Thu May 29 16:17:30 2014 +0200

    Neutron does not follow the RFC 3442 spec for DHCP

    When setting a gateway and additional host routes in neutron subnet, the
    gateway is only sent to clients via the router dhcp option, dhcp clients
    conforming to rfc3442 will ignore router option if
    classless-static-routes are available. This patch ensures setting both
    the router option and the classless-static-routes including the gateway

    Change-Id: Ia00b9385025020f848872309ae42ddac08528f53
    Closes-Bug: #1317935

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/icehouse
Review: https://review.openstack.org/124068

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/124068
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=143b2dcf6dfbf95f275ab5f52ec727d1aeb9badf
Submitter: Jenkins
Branch: stable/icehouse

commit 143b2dcf6dfbf95f275ab5f52ec727d1aeb9badf
Author: Christoph Arnold <email address hidden>
Date: Thu May 29 16:17:30 2014 +0200

    Neutron does not follow the RFC 3442 spec for DHCP

    When setting a gateway and additional host routes in neutron subnet, the
    gateway is only sent to clients via the router dhcp option, dhcp clients
    conforming to rfc3442 will ignore router option if
    classless-static-routes are available. This patch ensures setting both
    the router option and the classless-static-routes including the gateway

    Change-Id: Ia00b9385025020f848872309ae42ddac08528f53
    Closes-Bug: #1317935
    (cherry picked from commit ce59e63249dfcd86e782d056407e38e845cbe19c)