Merge branch 'route-offload-failure'

net: Add support for route offload failure notifications

Ido Schimmel  says:

====================
This is a complementary series to the one merged in commit 389cb1ec
("Merge branch 'add-notifications-when-route-hardware-flags-change'").

The previous series added RTM_NEWROUTE notifications to user space
whenever a route was successfully installed in hardware or when its
state in hardware changed. This allows routing daemons to delay
advertisement of routes until they are installed in hardware.

However, if route installation failed, a routing daemon will wait
indefinitely for a notification that will never come. The aim of this
series is to provide a failure notification via a new flag
(RTM_F_OFFLOAD_FAILED) in the RTM_NEWROUTE message. Upon such a
notification a routing daemon may decide to withdraw the route from the
FIB.

Series overview:

Patch #1 adds the new RTM_F_OFFLOAD_FAILED flag

Patches #2-#3 and #4-#5 add failure notifications to IPv4 and IPv6,
respectively

Patches #6-#8 teach netdevsim to fail route installation via a new knob
in debugfs

Patch #9 extends mlxsw to mark routes with the new flag

Patch #10 adds test cases for the new notification over netdevsim
====================

Signed-off-by: David S. Miller <davem@davemloft.net>