ip6_tunnel: fix ip6 tunnel lookup in collect_md mode

In collect_md mode, if the tun dev is down, it still can call
__ip6_tnl_rcv to receive on packets, and the rx statistics increase
improperly.

When the md tunnel is down, it's not neccessary to increase RX drops
for the tunnel device, packets would be recieved on fallback tunnel,
and the RX drops on fallback device will be increased as expected.

Fixes: 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels")
Cc: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 10a693a19323a947a9cb36b407421243c17a8009..ae73164559d5c4d7f2650ae63c56d76dc93b165c 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -171,7 +171,7 @@ ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_
        }
 
        t = rcu_dereference(ip6n->collect_md_tun);
-       if (t)
+       if (t && t->dev->flags & IFF_UP)
                return t;
 
        t = rcu_dereference(ip6n->tnls_wc[0]);