[PATCH net-next 1/2] net: mpls: Don't show nexthop if device has been deleted

[David Ahern]

If the device for a nexthop in a multipath route is deleted, the nexthop
is effectively removed from the route. Currently, a route dump still
returns the nexhop though without the device set:

$ ip -f mpls ro ls
100
        nexthopvia inet 10.11.1.2  dev br0
        nexthopvia inet 10.100.3.1  dev eth3
$ ip li del br0
$ ip -f mpls ro ls
100
        nexthopvia inet 10.11.1.2  dev * dead linkdown
        nexthopvia inet 10.100.3.1  dev eth3

Since the nexthop is effectively deleted, drop the hop from the route
dump.

Signed-off-by: David Ahern <d...@cumulusnetworks.com>
---
 net/mpls/af_mpls.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index cd8be8d5e4ad..3861f8dfa9c1 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -1769,13 +1769,15 @@ static int mpls_dump_route(struct sk_buff *skb, u32 
portid, u32 seq, int event,
                        goto nla_put_failure;
 
                for_nexthops(rt) {
+                       dev = rtnl_dereference(nh->nh_dev);
+                       if (!dev)
+                               continue;
+
                        rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
                        if (!rtnh)
                                goto nla_put_failure;
 
-                       dev = rtnl_dereference(nh->nh_dev);
-                       if (dev)
-                               rtnh->rtnh_ifindex = dev->ifindex;
+                       rtnh->rtnh_ifindex = dev->ifindex;
                        if (nh->nh_flags & RTNH_F_LINKDOWN) {
                                rtnh->rtnh_flags |= RTNH_F_LINKDOWN;
                                linkdown++;
-- 
2.1.4