There can be a case where the MAC address might change of the physical
interface attached to OVS. One common way this can happen is with a
bond. The MAC address of the bond may change depending on which slave
comes up first.

When this scenario happens, the host will now be using a new MAC, while
the OVN GR has the old MAC. This can cause hosts outside of the cluster
to constantly update their IP neighbor table with the wrong MAC for the
node, and cause traffic outage.

In order to prevent such a scenario, ensure that OVNK does not allow
traffic sent by OVN GR that does not match the current MAC address.

Signed-off-by: Tim Rozet <trozet@redhat.com>

In the scenario where an OVN GR may have the wrong mac, and traffic
disruption is present, the OVNK node process may stall at trying to
start the watch factory and wait for informer caches to sync. At this
point in time, ovnkube node is not able to start its OpenFlow manager
and program the needed flows to block the OVN GR from poisoning external
ip neighbor entries.

This commit adds a boostrap function which attempts to install basic
flows before anything else is done on the node during boot time. This is
a temporary flow installation that is only done when there is just a
single NORMAL flow in the external bridge and is overriden once OF
Manager starts.

Note this intentionally does not write the bootstrap flows if OVNK has
been killed, but the OVS flows from the previous run remain. It is only
for cases where OVS has no previously programmed flows, like on node
boot up.

Signed-off-by: Tim Rozet <trozet@redhat.com>

While OVNK is running a user could modify system settings so that the
MAC of the shared gw bridge may change. If this happens, OVNK needs to
detect it and update the node annotation so that the GR can be
reconfigured with the right MAC.

This commit takes the link manager that was added for egress IP and
abstracts it out of the egress IP controller. It also introduces passing
a handler function to link manager which gets executed during normal
runtime. This function will check to see if the MAC has changed on the
shared gw bridge and if so, update the the l3 gateway annotation.

Note, the link manager currently does not subscribe to netlink events
for links, but instead runs periodically and lists all interfaces. Since
changing a MAC address on the bridge is a disruptive action anyway, I
figured it is OK to leave our detection on a 30 second interval. MAC
changing on the bridge should be an extremely rare occurrence. However,
in the future we could add netlink subscriber and receive events when
the link changes.

Signed-off-by: Tim Rozet <trozet@redhat.com>

Changes-Include:
 - Move all ofm receiver functions to the proper file.
 - Ensure proper locking of the bridges.
 - Use proper encapsulation and expose functions in ofm to get
   bridge info.

Signed-off-by: Tim Rozet <trozet@redhat.com>

Now link manager will react to events for links, rather than just
running every so often.

Signed-off-by: Tim Rozet <trozet@redhat.com>

Signed-off-by: Tim Rozet <trozet@redhat.com>

Added an additional test that will check to make sure the openflow flows
for services are updated correctly when the IP address changes.

Signed-off-by: Tim Rozet <trozet@redhat.com>

Signed-off-by: Tim Rozet <trozet@redhat.com>