ipv6: do not drop vrf udp multicast packets

For bound udp sockets in a vrf, also check the sdif to get the index
for ingress devices enslaved to an l3mdev.
Signed-off-by: Dewi Morgan <morgand@vyatta.att-mail.com>
Signed-off-by: Mike Manning <mmanning@vyatta.att-mail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/udp.c

@@ -637,7 +637,7 @@ static int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 static bool __udp_v6_is_mcast_sock(struct net *net, struct sock *sk,
 				   __be16 loc_port, const struct in6_addr *loc_addr,
 				   __be16 rmt_port, const struct in6_addr *rmt_addr,
-				   int dif, unsigned short hnum)
+				   int dif, int sdif, unsigned short hnum)
 {
 	struct inet_sock *inet = inet_sk(sk);
 
@@ -649,7 +649,7 @@ static bool __udp_v6_is_mcast_sock(struct net *net, struct sock *sk,
 	    (inet->inet_dport && inet->inet_dport != rmt_port) ||
 	    (!ipv6_addr_any(&sk->sk_v6_daddr) &&
 		    !ipv6_addr_equal(&sk->sk_v6_daddr, rmt_addr)) ||
-	    (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif) ||
+	    !udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif) ||
 	    (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 		    !ipv6_addr_equal(&sk->sk_v6_rcv_saddr, loc_addr)))
 		return false;
@@ -683,6 +683,7 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
 	unsigned int offset = offsetof(typeof(*sk), sk_node);
 	unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
 	int dif = inet6_iif(skb);
+	int sdif = inet6_sdif(skb);
 	struct hlist_node *node;
 	struct sk_buff *nskb;
 
@@ -697,7 +698,8 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
 
 	sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
 		if (!__udp_v6_is_mcast_sock(net, sk, uh->dest, daddr,
-					    uh->source, saddr, dif, hnum))
+					    uh->source, saddr, dif, sdif,
+					    hnum))
 			continue;
 		/* If zero checksum and no_check is not on for
 		 * the socket then skip it.