net: bridge: Send notification when host join/leaves a group

The host can join or leave a multicast group on the brX interface, as
indicated by IGMP snooping.  This is tracked within the bridge
multicast code. Send a notification when this happens, in the same way
a notification is sent when a port of the bridge joins/leaves a group
because of IGMP snooping.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_mdb.c

@@ -317,7 +317,7 @@ static void __br_mdb_notify(struct net_device *dev, struct net_bridge_port *p,
 #endif
 
 	mdb.obj.orig_dev = port_dev;
-	if (port_dev && type == RTM_NEWMDB) {
+	if (p && port_dev && type == RTM_NEWMDB) {
 		complete_info = kmalloc(sizeof(*complete_info), GFP_ATOMIC);
 		if (complete_info) {
 			complete_info->port = p;
@@ -327,7 +327,7 @@ static void __br_mdb_notify(struct net_device *dev, struct net_bridge_port *p,
 			if (switchdev_port_obj_add(port_dev, &mdb.obj))
 				kfree(complete_info);
 		}
-	} else if (port_dev && type == RTM_DELMDB) {
+	} else if (p && port_dev && type == RTM_DELMDB) {
 		switchdev_port_obj_del(port_dev, &mdb.obj);
 	}
 
@@ -353,7 +353,10 @@ void br_mdb_notify(struct net_device *dev, struct net_bridge_port *port,
 	struct br_mdb_entry entry;
 
 	memset(&entry, 0, sizeof(entry));
+	if (port)
 		entry.ifindex = port->dev->ifindex;
+	else
+		entry.ifindex = dev->ifindex;
 	entry.addr.proto = group->proto;
 	entry.addr.u.ip4 = group->u.ip4;
 #if IS_ENABLED(CONFIG_IPV6)

net/bridge/br_multicast.c

@@ -250,6 +250,7 @@ static void br_multicast_group_expired(struct timer_list *t)
 		goto out;
 
 	mp->host_joined = false;
+	br_mdb_notify(br->dev, NULL, &mp->addr, RTM_DELMDB, 0);
 
 	if (mp->ports)
 		goto out;
@@ -773,7 +774,10 @@ static int br_multicast_add_group(struct net_bridge *br,
 		goto err;
 
 	if (!port) {
+		if (!mp->host_joined) {
 			mp->host_joined = true;
+			br_mdb_notify(br->dev, NULL, &mp->addr, RTM_NEWMDB, 0);
+		}
 		mod_timer(&mp->timer, now + br->multicast_membership_interval);
 		goto out;
 	}