vxlan: support for nexthop notifiers

vxlan driver registers for nexthop add/del notifiers to
cleanup fdb entries pointing to such nexthops.
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -81,6 +81,7 @@ struct vxlan_fdb {
 	u16		  flags;	/* see ndm_flags and below */
 	struct list_head  nh_list;
 	struct nexthop __rcu *nh;
+	struct vxlan_dev  *vdev;
 };
 
 #define NTF_VXLAN_ADDED_BY_USER 0x100
@@ -813,8 +814,9 @@ static int vxlan_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff)
 	return eth_gro_complete(skb, nhoff + sizeof(struct vxlanhdr));
 }
 
-static struct vxlan_fdb *vxlan_fdb_alloc(const u8 *mac, __u16 state,
-					 __be32 src_vni, __u16 ndm_flags)
+static struct vxlan_fdb *vxlan_fdb_alloc(struct vxlan_dev *vxlan, const u8 *mac,
+					 __u16 state, __be32 src_vni,
+					 __u16 ndm_flags)
 {
 	struct vxlan_fdb *f;
 
@@ -826,6 +828,7 @@ static struct vxlan_fdb *vxlan_fdb_alloc(const u8 *mac, __u16 state,
 	f->updated = f->used = jiffies;
 	f->vni = src_vni;
 	f->nh = NULL;
+	f->vdev = vxlan;
 	INIT_LIST_HEAD(&f->nh_list);
 	INIT_LIST_HEAD(&f->remotes);
 	memcpy(f->eth_addr, mac, ETH_ALEN);
@@ -923,7 +926,7 @@ static int vxlan_fdb_create(struct vxlan_dev *vxlan,
 		return -ENOSPC;
 
 	netdev_dbg(vxlan->dev, "add %pM -> %pIS\n", mac, ip);
-	f = vxlan_fdb_alloc(mac, state, src_vni, ndm_flags);
+	f = vxlan_fdb_alloc(vxlan, mac, state, src_vni, ndm_flags);
 	if (!f)
 		return -ENOMEM;
 
@@ -988,6 +991,7 @@ static void vxlan_fdb_destroy(struct vxlan_dev *vxlan, struct vxlan_fdb *f,
 	}
 
 	hlist_del_rcu(&f->hlist);
+	f->vdev = NULL;
 	call_rcu(&f->rcu, vxlan_fdb_free);
 }
 
@@ -4598,6 +4602,25 @@ static struct notifier_block vxlan_switchdev_notifier_block __read_mostly = {
 	.notifier_call = vxlan_switchdev_event,
 };
 
+static int vxlan_nexthop_event(struct notifier_block *nb,
+			       unsigned long event, void *ptr)
+{
+	struct nexthop *nh = ptr;
+	struct vxlan_fdb *fdb, *tmp;
+
+	if (!nh || event != NEXTHOP_EVENT_DEL)
+		return NOTIFY_DONE;
+
+	list_for_each_entry_safe(fdb, tmp, &nh->fdb_list, nh_list)
+		vxlan_fdb_destroy(fdb->vdev, fdb, false, false);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block vxlan_nexthop_notifier_block __read_mostly = {
+	.notifier_call = vxlan_nexthop_event,
+};
+
 static __net_init int vxlan_init_net(struct net *net)
 {
 	struct vxlan_net *vn = net_generic(net, vxlan_net_id);
@@ -4609,7 +4632,7 @@ static __net_init int vxlan_init_net(struct net *net)
 	for (h = 0; h < PORT_HASH_SIZE; ++h)
 		INIT_HLIST_HEAD(&vn->sock_list[h]);
 
-	return 0;
+	return register_nexthop_notifier(net, &vxlan_nexthop_notifier_block);
 }
 
 static void vxlan_destroy_tunnels(struct net *net, struct list_head *head)
@@ -4641,6 +4664,8 @@ static void __net_exit vxlan_exit_batch_net(struct list_head *net_list)
 	LIST_HEAD(list);
 
 	rtnl_lock();
+	list_for_each_entry(net, net_list, exit_list)
+		unregister_nexthop_notifier(net, &vxlan_nexthop_notifier_block);
 	list_for_each_entry(net, net_list, exit_list)
 		vxlan_destroy_tunnels(net, &list);