[PATCH v2 1/2] ip_tunnel: fix ip tunnel lookup in collect_md mode

[Haishuang Yan]

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

Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
Cc: Pravin B Shelar <pshelar@xxxxxxxxxx>
Signed-off-by: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx>

---
Change since v2:
  * Fix wrong recipient addresss
---
 net/ipv4/ip_tunnel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 0f1d876..a3caba1 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -176,7 +176,7 @@ struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn,
 		return cand;
 
 	t = rcu_dereference(itn->collect_md_tun);
-	if (t)
+	if (t && (t->dev->flags & IFF_UP))
 		return t;
 
 	if (itn->fb_tunnel_dev && itn->fb_tunnel_dev->flags & IFF_UP)
-- 
1.8.3.1