Comment 37 for bug 1274034

Reviewed: https://review.openstack.org/171003
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=aa7356b729f9672855980429677c969b6bab61a1
Submitter: Jenkins
Branch: master

commit aa7356b729f9672855980429677c969b6bab61a1
Author: Kevin Benton <email address hidden>
Date: Sun Mar 29 03:37:25 2015 -0700

    Add simple ARP spoofing protection

    Adds an option to setup OVS rules that will prevent
    ports attached to the agent from sending any ARP responses
    that contain an IP address not belonging to the port
    (in fixed IPs or allowed_address_pairs).

    It is disabled by default and requires an OVS version that
    can match on ARP fields. If it is too old, traffic will
    still flow but it won't have ARP spoofing protection.
    There is a sanity check to verify that ARP header matching
    is supported.

    This prevention is specific to OVS so it will not help with
    other plugins that use the reference iptables filtering. A
    non-OVS-specific general approach will require something like
    the ebtables integration in Ibc6d3d520c1383cf7e00f4bdeb7853a41ac4b14b.

    Details:
    A new table is added for ARP spoofing prevention. All ARP traffic
    on the local switching table is sent to this spoofing table.
    The spoofing table will allow all ARP requests because we aren't
    interested in them. It will then install an ARP response allow rule
    for each IP address the port is assigned. All other ARP responses are
    dropped.

    DocImpact
    SecurityImpact
    Partial-Bug: #1274034

    Change-Id: I7c079b779245a0af6bc793564fa8a560e4226afe