Comment 15 for bug 1774459

After talking with Miguel Ajo and Daniel Alvarez, plan is to intecept GARP packets and forward to local controller for processing
Swami had a WIP patch that inserted an OF rule to intercept, would need update to send to controller
https://review.openstack.org/#/c/601336/
For ryu look here:
 https://ryu.readthedocs.io/en/latest/ofproto_v1_0_ref.html#packet-in-message
https://ryu.readthedocs.io/en/latest/writing_ryu_app.html?highlight=packet%20in
ovn-controller handles incoming packets (packet-in) as controller here:
https://github.com/openvswitch/ovs/blob/769e6223daf3d6e51963dc3ee938a01fdc71a0d0/ovn/controller/pinctrl.c#L1221
https://github.com/openvswitch/ovs/blob/769e6223daf3d6e51963dc3ee938a01fdc71a0d0/ovn/controller/pinctrl.c#L1121
ODL is tracking this on https://jira.opendaylight.org/browse/NETVIRT-1402
Basically flows will be programmed dynamically when a GARP is recognized by the controller.