vxlan: Add hardware FDB learning

In order to allow devices to signal learning events to VXLAN, introduce
two new switchdev messages: SWITCHDEV_VXLAN_FDB_ADD_TO_BRIDGE and
SWITCHDEV_VXLAN_FDB_DEL_TO_BRIDGE.

Listen to these notifications in the vxlan driver. The FDB entries
learned this way have an NTF_EXT_LEARNED flag, and only entries marked
as such can be unlearned by the _DEL_ event. They are also immediately
marked as offloaded. This is the same behavior that the bridge driver
observes.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -3923,18 +3923,89 @@ vxlan_fdb_offloaded_set(struct net_device *dev,
 	spin_unlock_bh(&vxlan->hash_lock);
 }
 
+static int
+vxlan_fdb_external_learn_add(struct net_device *dev,
+			     struct switchdev_notifier_vxlan_fdb_info *fdb_info)
+{
+	struct vxlan_dev *vxlan = netdev_priv(dev);
+	int err;
+
+	spin_lock_bh(&vxlan->hash_lock);
+	err = vxlan_fdb_update(vxlan, fdb_info->eth_addr, &fdb_info->remote_ip,
+			       NUD_REACHABLE,
+			       NLM_F_CREATE | NLM_F_REPLACE,
+			       fdb_info->remote_port,
+			       fdb_info->vni,
+			       fdb_info->remote_vni,
+			       fdb_info->remote_ifindex,
+			       NTF_USE | NTF_SELF | NTF_EXT_LEARNED,
+			       false);
+	spin_unlock_bh(&vxlan->hash_lock);
+
+	return err;
+}
+
+static int
+vxlan_fdb_external_learn_del(struct net_device *dev,
+			     struct switchdev_notifier_vxlan_fdb_info *fdb_info)
+{
+	struct vxlan_dev *vxlan = netdev_priv(dev);
+	struct vxlan_fdb *f;
+	int err = 0;
+
+	spin_lock_bh(&vxlan->hash_lock);
+
+	f = vxlan_find_mac(vxlan, fdb_info->eth_addr, fdb_info->vni);
+	if (!f)
+		err = -ENOENT;
+	else if (f->flags & NTF_EXT_LEARNED)
+		err = __vxlan_fdb_delete(vxlan, fdb_info->eth_addr,
+					 fdb_info->remote_ip,
+					 fdb_info->remote_port,
+					 fdb_info->vni,
+					 fdb_info->remote_vni,
+					 fdb_info->remote_ifindex,
+					 false);
+
+	spin_unlock_bh(&vxlan->hash_lock);
+
+	return err;
+}
+
 static int vxlan_switchdev_event(struct notifier_block *unused,
 				 unsigned long event, void *ptr)
 {
 	struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
+	struct switchdev_notifier_vxlan_fdb_info *fdb_info;
+	int err = 0;
 
 	switch (event) {
 	case SWITCHDEV_VXLAN_FDB_OFFLOADED:
 		vxlan_fdb_offloaded_set(dev, ptr);
 		break;
+	case SWITCHDEV_VXLAN_FDB_ADD_TO_BRIDGE:
+		fdb_info = ptr;
+		err = vxlan_fdb_external_learn_add(dev, fdb_info);
+		if (err) {
+			err = notifier_from_errno(err);
+			break;
+		}
+		fdb_info->offloaded = true;
+		vxlan_fdb_offloaded_set(dev, fdb_info);
+		break;
+	case SWITCHDEV_VXLAN_FDB_DEL_TO_BRIDGE:
+		fdb_info = ptr;
+		err = vxlan_fdb_external_learn_del(dev, fdb_info);
+		if (err) {
+			err = notifier_from_errno(err);
+			break;
+		}
+		fdb_info->offloaded = false;
+		vxlan_fdb_offloaded_set(dev, fdb_info);
+		break;
 	}
 
-	return 0;
+	return err;
 }
 
 static struct notifier_block vxlan_switchdev_notifier_block __read_mostly = {

include/net/switchdev.h

@@ -146,6 +146,8 @@ enum switchdev_notifier_type {
 	SWITCHDEV_FDB_DEL_TO_DEVICE,
 	SWITCHDEV_FDB_OFFLOADED,
 
+	SWITCHDEV_VXLAN_FDB_ADD_TO_BRIDGE,
+	SWITCHDEV_VXLAN_FDB_DEL_TO_BRIDGE,
 	SWITCHDEV_VXLAN_FDB_ADD_TO_DEVICE,
 	SWITCHDEV_VXLAN_FDB_DEL_TO_DEVICE,
 	SWITCHDEV_VXLAN_FDB_OFFLOADED,