diff options
| author | David Ahern <dsa@cumulusnetworks.com> | 2017-03-10 14:11:39 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-03-22 12:43:34 +0100 |
| commit | 87c0286a07f93edc874c861a9159e586fc51ee6b (patch) | |
| tree | 4182cc0497cfb11728b8532ca5dc60c159d07cd1 /net/mpls | |
| parent | b61206e253020adbfde31f662ec7b5ea8b54935f (diff) | |
mpls: Do not decrement alive counter for unregister events
[ Upstream commit 79099aab38c8f5c746748b066ae74ba984fe2cc8 ]
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: c89359a42e2a4 ("mpls: support for dead routes")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/mpls')
| -rw-r--r-- | net/mpls/af_mpls.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c index 2a21ff14c07d..1309e2c34764 100644 --- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -956,7 +956,8 @@ static void mpls_ifdown(struct net_device *dev, int event) /* fall through */ case NETDEV_CHANGE: nh->nh_flags |= RTNH_F_LINKDOWN; - ACCESS_ONCE(rt->rt_nhn_alive) = rt->rt_nhn_alive - 1; + if (event != NETDEV_UNREGISTER) + ACCESS_ONCE(rt->rt_nhn_alive) = rt->rt_nhn_alive - 1; break; } if (event == NETDEV_UNREGISTER) |