[PATCH net 1/3] ip6_tunnel: Return an error when adding an existing tunnel.

[Steffen Klassert <steffen.klassert@secunet.com>]

ip6_tnl_locate() should not return an existing tunnel if
create is true. Otherwise it is possible to add the same
tunnel multiple times without getting an error.

So return NULL if the tunnel that should be created already
exists.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/ipv6/ip6_tunnel.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index f9de5a6..69a84b4 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -364,8 +364,12 @@ static struct ip6_tnl *ip6_tnl_locate(struct net *net,
 	     (t = rtnl_dereference(*tp)) != NULL;
 	     tp = &t->next) {
 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
-		    ipv6_addr_equal(remote, &t->parms.raddr))
+		    ipv6_addr_equal(remote, &t->parms.raddr)) {
+			if (create)
+				return NULL;
+
 			return t;
+		}
 	}
 	if (!create)
 		return NULL;
-- 
1.9.1