alistair23-linux/net/mpls
David Ahern 79099aab38 mpls: Do not decrement alive counter for unregister events
Multipath routes can be rendered usesless when a device in one of the
paths is deleted. For example:

$ ip -f mpls ro ls
100
	nexthop as to 200 via inet 172.16.2.2  dev virt12
	nexthop as to 300 via inet 172.16.3.2  dev br0
101
	nexthop as to 201 via inet6 2000:2::2  dev virt12
	nexthop as to 301 via inet6 2000:3::2  dev br0

$ ip li del br0

When br0 is deleted the other hop is not considered in
mpls_select_multipath because of the alive check -- rt_nhn_alive
is 0.

rt_nhn_alive is decremented once in mpls_ifdown when the device is taken
down (NETDEV_DOWN) and again when it is deleted (NETDEV_UNREGISTER). For
a 2 hop route, deleting one device drops the alive count to 0. Since
devices are taken down before unregistering, the decrement on
NETDEV_UNREGISTER is redundant.

Fixes: c89359a42e ("mpls: support for dead routes")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-12 23:45:36 -07:00
..
af_mpls.c mpls: Do not decrement alive counter for unregister events 2017-03-12 23:45:36 -07:00
internal.h net: mpls: Add support for netconf 2017-02-20 11:13:37 -05:00
Kconfig mpls: ip tunnel support 2015-07-21 10:39:05 -07:00
Makefile mpls: ip tunnel support 2015-07-21 10:39:05 -07:00
mpls_gso.c net: mpls: Fixups for GSO 2016-08-30 22:27:18 -07:00
mpls_iptunnel.c lwtunnel: remove device arg to lwtunnel_build_state 2017-01-30 15:14:22 -05:00