net: ipv6: Keep nexthop of multipath route on admin down
IPv6 deletes route entries associated with multipath routes on an
admin down where IPv4 does not. For example:
$ ip ro ls vrf red
unreachable default metric 8192
1.1.1.0/24 metric 64
nexthop via 10.100.1.254 dev eth1 weight 1
nexthop via 10.100.2.254 dev eth2 weight 1
10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.4
10.100.2.0/24 dev eth2 proto kernel scope link src 10.100.2.4
$ ip -6 ro ls vrf red
2001:db8:1::/120 dev eth1 proto kernel metric 256 pref medium
2001:db8:2:: dev red proto none metric 0 pref medium
2001:db8:2::/120 dev eth2 proto kernel metric 256 pref medium
2001:db8:11::/120 via 2001:db8:1::16 dev eth1 metric 1024 pref medium
2001:db8:11::/120 via 2001:db8:2::17 dev eth2 metric 1024 pref medium
...
Set link down:
$ ip li set eth1 down
IPv4 retains the multihop route but flags eth1 route as dead:
$ ip ro ls vrf red
unreachable default metric 8192
1.1.1.0/24
nexthop via 10.100.1.16 dev eth1 weight 1 dead linkdown
nexthop via 10.100.2.16 dev eth2 weight 1
10.100.2.0/24 dev eth2 proto kernel scope link src 10.100.2.4
and IPv6 deletes the route as part of flushing all routes for the device:
$ ip -6 ro ls vrf red
2001:db8:2:: dev red proto none metric 0 pref medium
2001:db8:2::/120 dev eth2 proto kernel metric 256 pref medium
2001:db8:11::/120 via 2001:db8:2::17 dev eth2 metric 1024 pref medium
...
Worse, on admin up of the device the multipath route has to be deleted
to get this leg of the route re-added.
This patch keeps routes that are part of a multipath route if
ignore_routes_with_linkdown is set with the dead and linkdown flags
enabling consistency between IPv4 and IPv6:
$ ip -6 ro ls vrf red
2001:db8:2:: dev red proto none metric 0 pref medium
2001:db8:2::/120 dev eth2 proto kernel metric 256 pref medium
2001:db8:11::/120 via 2001:db8:1::16 dev eth1 metric 1024 dead linkdown pref medium
2001:db8:11::/120 via 2001:db8:2::17 dev eth2 metric 1024 pref medium
...
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed