bridge: Introduce BR_PROMISC flag

Introduce a BR_PROMISC per-port flag that will help us track if the
current port is supposed to be in promiscuous mode or not.  For now,
always start in promiscuous mode.

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

net/bridge/br_if.c

@@ -238,7 +238,7 @@ static struct net_bridge_port *new_nbp(struct net_bridge *br,
 	p->path_cost = port_cost(dev);
 	p->priority = 0x8000 >> BR_PORT_BITS;
 	p->port_no = index;
-	p->flags = BR_LEARNING | BR_FLOOD;
+	p->flags = BR_LEARNING | BR_FLOOD | BR_PROMISC;
 	br_init_port(p);
 	p->state = BR_STATE_DISABLED;
 	br_stp_port_timer_init(p);

net/bridge/br_private.h

@@ -175,6 +175,7 @@ struct net_bridge_port
 #define BR_LEARNING		0x00000020
 #define BR_FLOOD		0x00000040
 #define BR_AUTO_MASK (BR_FLOOD | BR_LEARNING)
+#define BR_PROMISC		0x00000080
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 	struct bridge_mcast_query	ip4_query;
@@ -200,6 +201,7 @@ struct net_bridge_port
 };
 
 #define br_auto_port(p) ((p)->flags & BR_AUTO_MASK)
+#define br_promisc_port(p) ((p)->flags & BR_PROMISC)
 
 #define br_port_exists(dev) (dev->priv_flags & IFF_BRIDGE_PORT)