net: bridge: allow IPv6 when multicast flood is disabled

[ Upstream commit 8953de2f ]

Even with multicast flooding turned off, IPv6 ND should still work so
that IPv6 connectivity is provided. Allow this by continuing to flood
multicast traffic originated by us.

Fixes: b6cb5ac8 ("net: bridge: add per-port multicast flood flag")
Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Mike Manning <mmanning@brocade.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/bridge/br_forward.c

@@ -186,8 +186,9 @@ void br_flood(struct net_bridge *br, struct sk_buff *skb,
 		/* Do not flood unicast traffic to ports that turn it off */
 		if (pkt_type == BR_PKT_UNICAST && !(p->flags & BR_FLOOD))
 			continue;
+		/* Do not flood if mc off, except for traffic we originate */
 		if (pkt_type == BR_PKT_MULTICAST &&
-		    !(p->flags & BR_MCAST_FLOOD))
+		    !(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
 			continue;
 
 		/* Do not flood to ports that enable proxy ARP */