net: bridge: Add support for notifying devices about FDB add/del

Currently the bridge doesn't notify the underlying devices about new
FDBs learned. The FDB sync is placed on the switchdev notifier chain
because devices may potentially learn FDB that are not directly related
to their ports, for example:

1. Mixed SW/HW bridge - FDBs that point to the ASICs external devices
                        should be offloaded as CPU traps in order to
			perform forwarding in slow path.
2. EVPN - Externally learned FDBs for the vtep device.

Notification is sent only about static FDB add/del. This is done due
to fact that currently this is the only scenario supported by switch
drivers.
Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Reviewed-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c

@@ -1867,7 +1867,7 @@ static void mlxsw_sp_fdb_call_notifiers(bool learning_sync, bool adding,
 	if (learning_sync) {
 		info.addr = mac;
 		info.vid = vid;
-		notifier_type = adding ? SWITCHDEV_FDB_ADD : SWITCHDEV_FDB_DEL;
+		notifier_type = adding ? SWITCHDEV_FDB_ADD_TO_BRIDGE : SWITCHDEV_FDB_DEL_TO_BRIDGE;
 		call_switchdev_notifiers(notifier_type, dev, &info.info);
 	}
 }

drivers/net/ethernet/rocker/rocker_ofdpa.c

@@ -1939,10 +1939,10 @@ static void ofdpa_port_fdb_learn_work(struct work_struct *work)
 
 	rtnl_lock();
 	if (learned && removing)
-		call_switchdev_notifiers(SWITCHDEV_FDB_DEL,
+		call_switchdev_notifiers(SWITCHDEV_FDB_DEL_TO_BRIDGE,
 					 lw->ofdpa_port->dev, &info.info);
 	else if (learned && !removing)
-		call_switchdev_notifiers(SWITCHDEV_FDB_ADD,
+		call_switchdev_notifiers(SWITCHDEV_FDB_ADD_TO_BRIDGE,
 					 lw->ofdpa_port->dev, &info.info);
 	rtnl_unlock();
 

include/net/switchdev.h

@@ -155,8 +155,10 @@ struct switchdev_ops {
 };
 
 enum switchdev_notifier_type {
-	SWITCHDEV_FDB_ADD = 1,
-	SWITCHDEV_FDB_DEL,
+	SWITCHDEV_FDB_ADD_TO_BRIDGE = 1,
+	SWITCHDEV_FDB_DEL_TO_BRIDGE,
+	SWITCHDEV_FDB_ADD_TO_DEVICE,
+	SWITCHDEV_FDB_DEL_TO_DEVICE,
 };
 
 struct switchdev_notifier_info {

net/bridge/br.c

@@ -138,14 +138,14 @@ static int br_switchdev_event(struct notifier_block *unused,
 	br = p->br;
 
 	switch (event) {
-	case SWITCHDEV_FDB_ADD:
+	case SWITCHDEV_FDB_ADD_TO_BRIDGE:
 		fdb_info = ptr;
 		err = br_fdb_external_learn_add(br, p, fdb_info->addr,
 						fdb_info->vid);
 		if (err)
 			err = notifier_from_errno(err);
 		break;
-	case SWITCHDEV_FDB_DEL:
+	case SWITCHDEV_FDB_DEL_TO_BRIDGE:
 		fdb_info = ptr;
 		err = br_fdb_external_learn_del(br, p, fdb_info->addr,
 						fdb_info->vid);

net/bridge/br_fdb.c

@@ -690,6 +690,8 @@ static void fdb_notify(struct net_bridge *br,
 	struct sk_buff *skb;
 	int err = -ENOBUFS;
 
+	br_switchdev_fdb_notify(fdb, type);
+
 	skb = nlmsg_new(fdb_nlmsg_size(), GFP_ATOMIC);
 	if (skb == NULL)
 		goto errout;

net/bridge/br_private.h

@@ -1085,6 +1085,8 @@ bool nbp_switchdev_allowed_egress(const struct net_bridge_port *p,
 int br_switchdev_set_port_flag(struct net_bridge_port *p,
 			       unsigned long flags,
 			       unsigned long mask);
+void br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb,
+			     int type);
 #else
 static inline int nbp_switchdev_mark_set(struct net_bridge_port *p)
 {
@@ -1108,6 +1110,11 @@ static inline int br_switchdev_set_port_flag(struct net_bridge_port *p,
 {
 	return 0;
 }
+
+static inline void
+br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb, int type)
+{
+}
 #endif /* CONFIG_NET_SWITCHDEV */
 
 #endif

net/bridge/br_switchdev.c

@@ -98,3 +98,36 @@ int br_switchdev_set_port_flag(struct net_bridge_port *p,
 
 	return 0;
 }
+
+static void
+br_switchdev_fdb_call_notifiers(bool adding, const unsigned char *mac,
+				u16 vid, struct net_device *dev)
+{
+	struct switchdev_notifier_fdb_info info;
+	unsigned long notifier_type;
+
+	info.addr = mac;
+	info.vid = vid;
+	notifier_type = adding ? SWITCHDEV_FDB_ADD_TO_DEVICE : SWITCHDEV_FDB_DEL_TO_DEVICE;
+	call_switchdev_notifiers(notifier_type, dev, &info.info);
+}
+
+void
+br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb, int type)
+{
+	if (!fdb->added_by_user)
+		return;
+
+	switch (type) {
+	case RTM_DELNEIGH:
+		br_switchdev_fdb_call_notifiers(false, fdb->addr.addr,
+						fdb->vlan_id,
+						fdb->dst->dev);
+		break;
+	case RTM_NEWNEIGH:
+		br_switchdev_fdb_call_notifiers(true, fdb->addr.addr,
+						fdb->vlan_id,
+						fdb->dst->dev);
+		break;
+	}
+}