[PATCH v4 net-next 1/8] vxlan: update default fdb entries when the lower device changes

@@ -4452,6 +4452,7 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],
 	struct net_device *lowerdev;
 	struct vxlan_config conf;
 	struct vxlan_rdst *dst;
+	u32 new_ifindex;
 	int err;
 
 	if (!rtnl_dev_link_net_capable(dev, vxlan->net))

@@ -4475,13 +4476,16 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],
 	if (err)
 		return err;
 
+	/* vxlan_config_apply() only commits remote_ifindex if lowerdev is set */
+	new_ifindex = lowerdev ? conf.remote_ifindex : dst->remote_ifindex;
+
 	rem_ip_changed = !vxlan_addr_equal(&conf.remote_ip, &dst->remote_ip);
 	change_igmp = vxlan->dev->flags & IFF_UP &&
 		      (rem_ip_changed ||
-		       dst->remote_ifindex != conf.remote_ifindex);
+		       dst->remote_ifindex != new_ifindex);
 
 	/* handle default dst entry */
-	if (rem_ip_changed) {
+	if (rem_ip_changed || dst->remote_ifindex != new_ifindex) {
 		spin_lock_bh(&vxlan->hash_lock);
 		if (!vxlan_addr_any(&conf.remote_ip)) {
 			err = vxlan_fdb_update(vxlan, all_zeros_mac,

@@ -4490,7 +4494,7 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],
 					       NLM_F_APPEND | NLM_F_CREATE,
 					       vxlan->cfg.dst_port,
 					       conf.vni, conf.vni,
-					       conf.remote_ifindex,
+					       new_ifindex,
 					       NTF_SELF, 0, true, extack);
 			if (err) {
 				spin_unlock_bh(&vxlan->hash_lock);

@@ -4509,12 +4513,14 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],
 					   true);
 		spin_unlock_bh(&vxlan->hash_lock);
 
-		/* If vni filtering device, also update fdb entries of
-		 * all vnis that were using default remote ip
+		/* If vni filtering device, also update default fdb entries of
+		 * all vnis
 		 */
 		if (vxlan->cfg.flags & VXLAN_F_VNIFILTER) {
 			err = vxlan_vnilist_update_group(vxlan, &dst->remote_ip,
-							 &conf.remote_ip, extack);
+							 &conf.remote_ip,
+							 dst->remote_ifindex,
+							 new_ifindex, extack);
 			if (err) {
 				netdev_adjacent_change_abort(dst->remote_dev,
 							     lowerdev, dev);

@@ -216,6 +216,7 @@ void vxlan_vs_del_vnigrp(struct vxlan_dev *vxlan);
 int vxlan_vnilist_update_group(struct vxlan_dev *vxlan,
 			       union vxlan_addr *old_remote_ip,
 			       union vxlan_addr *new_remote_ip,
+			       u32 old_ifindex, u32 new_ifindex,
 			       struct netlink_ext_ack *extack);
 
 

@@ -473,11 +473,16 @@ static const struct nla_policy vni_filter_policy[VXLAN_VNIFILTER_MAX + 1] = {
 static int vxlan_update_default_fdb_entry(struct vxlan_dev *vxlan, __be32 vni,
 					  union vxlan_addr *old_remote_ip,
 					  union vxlan_addr *remote_ip,
+					  u32 old_ifindex, u32 new_ifindex,
 					  struct netlink_ext_ack *extack)
 {
-	struct vxlan_rdst *dst = &vxlan->default_dst;
 	int err = 0;
 
+	if (old_remote_ip && remote_ip &&
+	    vxlan_addr_equal(old_remote_ip, remote_ip) &&
+	    old_ifindex == new_ifindex)
+		return 0;
+
 	spin_lock_bh(&vxlan->hash_lock);
 	if (remote_ip && !vxlan_addr_any(remote_ip)) {
 		err = vxlan_fdb_update(vxlan, all_zeros_mac,

@@ -487,7 +492,7 @@ static int vxlan_update_default_fdb_entry(struct vxlan_dev *vxlan, __be32 vni,
 				       vxlan->cfg.dst_port,
 				       vni,
 				       vni,
-				       dst->remote_ifindex,
+				       new_ifindex,
 				       NTF_SELF, 0, true, extack);
 		if (err) {
 			spin_unlock_bh(&vxlan->hash_lock);

@@ -500,7 +505,7 @@ static int vxlan_update_default_fdb_entry(struct vxlan_dev *vxlan, __be32 vni,
 				   *old_remote_ip,
 				   vxlan->cfg.dst_port,
 				   vni, vni,
-				   dst->remote_ifindex,
+				   old_ifindex,
 				   true);
 	}
 	spin_unlock_bh(&vxlan->hash_lock);

@@ -546,6 +551,8 @@ static int vxlan_vni_update_group(struct vxlan_dev *vxlan,
 
 	ret = vxlan_update_default_fdb_entry(vxlan, vninode->vni,
 					     oldrip, newrip,
+					     dst->remote_ifindex,
+					     dst->remote_ifindex,
 					     extack);
 	if (ret)
 		goto out;

@@ -583,8 +590,10 @@ static int vxlan_vni_update_group(struct vxlan_dev *vxlan,
 int vxlan_vnilist_update_group(struct vxlan_dev *vxlan,
 			       union vxlan_addr *old_remote_ip,
 			       union vxlan_addr *new_remote_ip,
+			       u32 old_ifindex, u32 new_ifindex,
 			       struct netlink_ext_ack *extack)
 {
+	union vxlan_addr *oldrip, *newrip;
 	struct list_head *headp, *hpos;
 	struct vxlan_vni_group *vg;
 	struct vxlan_vni_node *vent;

@@ -595,14 +604,24 @@ int vxlan_vnilist_update_group(struct vxlan_dev *vxlan,
 	headp = &vg->vni_list;
 	list_for_each_prev(hpos, headp) {
 		vent = list_entry(hpos, struct vxlan_vni_node, vlist);
+
 		if (vxlan_addr_any(&vent->remote_ip)) {
-			ret = vxlan_update_default_fdb_entry(vxlan, vent->vni,
-							     old_remote_ip,
-							     new_remote_ip,
-							     extack);
-			if (ret)
-				return ret;
+			oldrip = old_remote_ip;
+			newrip = new_remote_ip;
+		} else {
+			/* A vni with its own group keeps it, but its fdb entry
+			 * is still keyed on the device remote_ifindex.
+			 */
+			oldrip = &vent->remote_ip;
+			newrip = &vent->remote_ip;
 		}
+
+		ret = vxlan_update_default_fdb_entry(vxlan, vent->vni,
+						     oldrip, newrip,
+						     old_ifindex, new_ifindex,
+						     extack);
+		if (ret)
+			return ret;
 	}
 
 	return 0;