macvlan: Add netlink attribute for broadcast cutoff

Make the broadcast cutoff configurable through netlink. Note
that macvlan is weird because there is no central device for
us to configure (the lowerdev could be anything). So all the
options are duplicated over what could be thousands of child
devices.

IFLA_MACVLAN_BC_QUEUE_LEN took the approach of taking the maximum
of all child device settings. This is unnecessary as we could
simply store the option in the port device and take the last
child device that gets updated as the value to use.

Signed-off-by: Herbert Xu <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/macvlan.c

···
 	struct sk_buff_head	bc_queue;
 	struct work_struct	bc_work;
 	u32			bc_queue_len_used;
+	int			bc_cutoff;
 	u32			flags;
 	int			count;
 	struct hlist_head	vlan_source_hash[MACVLAN_HASH_SIZE];
···
 	}
 }
 
+static void macvlan_recompute_bc_filter(struct macvlan_dev *vlan)
+{
+	macvlan_compute_filter(vlan->port->bc_filter, vlan->lowerdev, NULL,
+			       vlan->port->bc_cutoff);
+}
+
 static void macvlan_set_mac_lists(struct net_device *dev)
 {
 	struct macvlan_dev *vlan = netdev_priv(dev);
···
 	 */
 	macvlan_compute_filter(vlan->port->mc_filter, vlan->lowerdev, NULL,
 			       0);
-	macvlan_compute_filter(vlan->port->bc_filter, vlan->lowerdev, NULL,
-			       1);
+	macvlan_recompute_bc_filter(vlan);
+}
+
+static void update_port_bc_cutoff(struct macvlan_dev *vlan, int cutoff)
+{
+	if (vlan->port->bc_cutoff == cutoff)
+		return;
+
+	vlan->port->bc_cutoff = cutoff;
+	macvlan_recompute_bc_filter(vlan);
 }
 
 static int macvlan_change_mtu(struct net_device *dev, int new_mtu)
···
 		INIT_HLIST_HEAD(&port->vlan_source_hash[i]);
 
 	port->bc_queue_len_used = 0;
+	port->bc_cutoff = 1;
 	skb_queue_head_init(&port->bc_queue);
 	INIT_WORK(&port->bc_work, macvlan_process_broadcast);
 
···
 	if (data && data[IFLA_MACVLAN_BC_QUEUE_LEN])
 		vlan->bc_queue_len_req = nla_get_u32(data[IFLA_MACVLAN_BC_QUEUE_LEN]);
 
+	if (data && data[IFLA_MACVLAN_BC_CUTOFF])
+		update_port_bc_cutoff(
+			vlan, nla_get_s32(data[IFLA_MACVLAN_BC_CUTOFF]));
+
 	err = register_netdevice(dev);
 	if (err < 0)
 		goto destroy_macvlan_port;
···
 		update_port_bc_queue_len(vlan->port);
 	}
 
+	if (data && data[IFLA_MACVLAN_BC_CUTOFF])
+		update_port_bc_cutoff(
+			vlan, nla_get_s32(data[IFLA_MACVLAN_BC_CUTOFF]));
+
 	if (set_mode)
 		vlan->mode = mode;
 	if (data && data[IFLA_MACVLAN_MACADDR_MODE]) {
···
 	if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN, vlan->bc_queue_len_req))
 		goto nla_put_failure;
 	if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN_USED, port->bc_queue_len_used))
+		goto nla_put_failure;
+	if (port->bc_cutoff != 1 &&
+	    nla_put_s32(skb, IFLA_MACVLAN_BC_CUTOFF, port->bc_cutoff))
 		goto nla_put_failure;
 	return 0;
 

include/uapi/linux/if_link.h

···
 	IFLA_MACVLAN_MACADDR_COUNT,
 	IFLA_MACVLAN_BC_QUEUE_LEN,
 	IFLA_MACVLAN_BC_QUEUE_LEN_USED,
+	IFLA_MACVLAN_BC_CUTOFF,
 	__IFLA_MACVLAN_MAX,
 };
 

tools/include/uapi/linux/if_link.h

···
 	IFLA_MACVLAN_MACADDR_COUNT,
 	IFLA_MACVLAN_BC_QUEUE_LEN,
 	IFLA_MACVLAN_BC_QUEUE_LEN_USED,
+	IFLA_MACVLAN_BC_CUTOFF,
 	__IFLA_MACVLAN_MAX,
 };