ipv6: Make MLD packets to only be processed locally

commit 4c938d22 upstream.

Before commit daad1512 ("ipv6: Make ipv6_is_mld() inline and use it
from ip6_mc_input().") MLD packets were only processed locally. After the
change, a copy of MLD packet goes through ip6_mr_input, causing
MRT6MSG_NOCACHE message to be generated to user space.

Make MLD packet only processed locally.

Fixes: daad1512 ("ipv6: Make ipv6_is_mld() inline and use it from ip6_mc_input().")
Signed-off-by: Hermin Anggawijaya <hermin.anggawijaya@alliedtelesis.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

net/ipv6/ip6_input.c

@@ -329,10 +329,10 @@ int ip6_mc_input(struct sk_buff *skb)
 				if (offset < 0)
 					goto out;
 
-				if (!ipv6_is_mld(skb, nexthdr, offset))
-					goto out;
+				if (ipv6_is_mld(skb, nexthdr, offset))
+					deliver = true;
 
-				deliver = true;
+				goto out;
 			}
 			/* unknown RA - process it normally */
 		}