bridge: Add a flag to control unicast packet flood.

Add a flag to control flood of unicast traffic.  By default, flood is
on and the bridge will flood unicast traffic if it doesn't know
the destination.  When the flag is turned off, unicast traffic
without an FDB will not be forwarded to the specified port.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_device.c

@@ -58,10 +58,10 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 	skb_pull(skb, ETH_HLEN);
 
 	if (is_broadcast_ether_addr(dest))
-		br_flood_deliver(br, skb);
+		br_flood_deliver(br, skb, false);
 	else if (is_multicast_ether_addr(dest)) {
 		if (unlikely(netpoll_tx_running(dev))) {
-			br_flood_deliver(br, skb);
+			br_flood_deliver(br, skb, false);
 			goto out;
 		}
 		if (br_multicast_rcv(br, NULL, skb)) {
@@ -73,11 +73,11 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 		if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb))
 			br_multicast_deliver(mdst, skb);
 		else
-			br_flood_deliver(br, skb);
+			br_flood_deliver(br, skb, false);
 	} else if ((dst = __br_fdb_get(br, dest, vid)) != NULL)
 		br_deliver(dst->dst, skb);
 	else
-		br_flood_deliver(br, skb);
+		br_flood_deliver(br, skb, true);
 
 out:
 	rcu_read_unlock();