[PATCH] ipv4: ip_tunnels: disable dst cache for nbma gre tunnels

["Timo Teräs" <timo.teras@iki.fi>]

The connected check fails to check for ip_gre nbma mode tunnels
properly. ip_gre creates temporary tnl_params with daddr specified
to pass-in the actual target on per-packet basis from neighbor
layer. Detect these tunnels by inspecting the actual tunnel
configuration instead.

Fixes: 7d442fab0a67 ("ipv4: Cache dst in tunnels")
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Cc: Tom Herbert <therbert@google.com>
Cc: Eric Dumazet <edumazet@google.com>
---
Should go to 3.14-stable too.

(This does not fix all NBMA GRE regressions in 3.14.
 I'm also getting weird oopses from GRO; will post soon more info.)

 net/ipv4/ip_tunnel.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index e77381d..100caf5 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -538,9 +538,10 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 	unsigned int max_headroom;	/* The extra header space needed */
 	__be32 dst;
 	int err;
-	bool connected = true;
+	bool connected;
 
 	inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
+	connected = (tunnel->daddr != 0);
 
 	dst = tnl_params->daddr;
 	if (dst == 0) {
-- 
1.9.3