Merge branch 'IGMP-snooping-for-local-traffic'

Andrew Lunn says:

====================
IGMP snooping for local traffic

The linux bridge supports IGMP snooping. It will listen to IGMP
reports on bridge ports and keep track of which groups have been
joined on an interface. It will then forward multicast based on this
group membership.

When the bridge adds or removed groups from an interface, it uses
switchdev to request the hardware add an mdb to a port, so the
hardware can perform the selective forwarding between ports.

What is not covered by the current bridge code, is IGMP joins/leaves
from the host on the brX interface. These are not reported via
switchdev so that hardware knows the local host is interested in the
multicast frames.

Luckily, the bridge does track joins/leaves on the brX interface. The
code is obfusticated, which is why i missed it with my first attempt.
So the first patch tries to remove this obfustication. Currently,
there is no notifications sent when the bridge interface joins a
group. The second patch adds them. bridge monitor then shows
joins/leaves in the same way as for other ports of the bridge.

Then starts the work passing down to the hardware that the host has
joined/left a group. The existing switchdev mdb object cannot be used,
since the semantics are different. The existing
SWITCHDEV_OBJ_ID_PORT_MDB is used to indicate a specific multicast
group should be forwarded out that port of the switch. However here we
require the exact opposite. We want multicast frames for the group
received on the port to the forwarded to the host. Hence add a new
object SWITCHDEV_OBJ_ID_HOST_MDB, a multicast database entry to
forward to the host. This new object is then propagated through the
DSA layers. No DSA driver changes should be needed, this should just
work...

This version fixes up the nitpick from Nikolay, removes an unrelated
white space change, and adds in a patch adding a few const attributes
to a couple of functions taking a port parameter, in order to stop the
following patch produces warnings.
====================
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/switchdev.h

@@ -76,6 +76,7 @@ enum switchdev_obj_id {
 	SWITCHDEV_OBJ_ID_UNDEFINED,
 	SWITCHDEV_OBJ_ID_PORT_VLAN,
 	SWITCHDEV_OBJ_ID_PORT_MDB,
+	SWITCHDEV_OBJ_ID_HOST_MDB,
 };
 
 struct switchdev_obj {

net/bridge/br_input.c

@@ -137,7 +137,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
 		mdst = br_mdb_get(br, skb, vid);
 		if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
 		    br_multicast_querier_exists(br, eth_hdr(skb))) {
-			if ((mdst && mdst->mglist) ||
+			if ((mdst && mdst->host_joined) ||
 			    br_multicast_is_router(br)) {
 				local_rcv = true;
 				br->dev->stats.multicast++;

net/bridge/br_mdb.c

@@ -292,6 +292,46 @@ static void br_mdb_complete(struct net_device *dev, int err, void *priv)
 	kfree(priv);
 }
 
+static void br_mdb_switchdev_host_port(struct net_device *dev,
+				       struct net_device *lower_dev,
+				       struct br_mdb_entry *entry, int type)
+{
+	struct switchdev_obj_port_mdb mdb = {
+		.obj = {
+			.id = SWITCHDEV_OBJ_ID_HOST_MDB,
+			.flags = SWITCHDEV_F_DEFER,
+		},
+		.vid = entry->vid,
+	};
+
+	if (entry->addr.proto == htons(ETH_P_IP))
+		ip_eth_mc_map(entry->addr.u.ip4, mdb.addr);
+#if IS_ENABLED(CONFIG_IPV6)
+	else
+		ipv6_eth_mc_map(&entry->addr.u.ip6, mdb.addr);
+#endif
+
+	mdb.obj.orig_dev = dev;
+	switch (type) {
+	case RTM_NEWMDB:
+		switchdev_port_obj_add(lower_dev, &mdb.obj);
+		break;
+	case RTM_DELMDB:
+		switchdev_port_obj_del(lower_dev, &mdb.obj);
+		break;
+	}
+}
+
+static void br_mdb_switchdev_host(struct net_device *dev,
+				  struct br_mdb_entry *entry, int type)
+{
+	struct net_device *lower_dev;
+	struct list_head *iter;
+
+	netdev_for_each_lower_dev(dev, lower_dev, iter)
+		br_mdb_switchdev_host_port(dev, lower_dev, entry, type);
+}
+
 static void __br_mdb_notify(struct net_device *dev, struct net_bridge_port *p,
 			    struct br_mdb_entry *entry, int type)
 {
@@ -317,7 +357,7 @@ 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;
@@ -327,10 +367,13 @@ 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);
 	}
 
+	if (!p)
+		br_mdb_switchdev_host(dev, entry, type);
+
 	skb = nlmsg_new(rtnl_mdb_nlmsg_size(), GFP_ATOMIC);
 	if (!skb)
 		goto errout;
@@ -353,7 +396,10 @@ void br_mdb_notify(struct net_device *dev, struct net_bridge_port *port,
 	struct br_mdb_entry entry;
 
 	memset(&entry, 0, sizeof(entry));
-	entry.ifindex = port->dev->ifindex;
+	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)
@@ -655,7 +701,7 @@ static int __br_mdb_del(struct net_bridge *br, struct br_mdb_entry *entry)
 		call_rcu_bh(&p->rcu, br_multicast_free_pg);
 		err = 0;
 
-		if (!mp->ports && !mp->mglist &&
+		if (!mp->ports && !mp->host_joined &&
 		    netif_running(br->dev))
 			mod_timer(&mp->timer, jiffies);
 		break;

net/bridge/br_multicast.c

@@ -249,7 +249,8 @@ static void br_multicast_group_expired(struct timer_list *t)
 	if (!netif_running(br->dev) || timer_pending(&mp->timer))
 		goto out;
 
-	mp->mglist = false;
+	mp->host_joined = false;
+	br_mdb_notify(br->dev, NULL, &mp->addr, RTM_DELMDB, 0);
 
 	if (mp->ports)
 		goto out;
@@ -292,7 +293,7 @@ static void br_multicast_del_pg(struct net_bridge *br,
 			      p->flags);
 		call_rcu_bh(&p->rcu, br_multicast_free_pg);
 
-		if (!mp->ports && !mp->mglist &&
+		if (!mp->ports && !mp->host_joined &&
 		    netif_running(br->dev))
 			mod_timer(&mp->timer, jiffies);
 
@@ -773,7 +774,10 @@ static int br_multicast_add_group(struct net_bridge *br,
 		goto err;
 
 	if (!port) {
-		mp->mglist = true;
+		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;
 	}
@@ -1477,7 +1481,7 @@ static int br_ip4_multicast_query(struct net_bridge *br,
 
 	max_delay *= br->multicast_last_member_count;
 
-	if (mp->mglist &&
+	if (mp->host_joined &&
 	    (timer_pending(&mp->timer) ?
 	     time_after(mp->timer.expires, now + max_delay) :
 	     try_to_del_timer_sync(&mp->timer) >= 0))
@@ -1561,7 +1565,7 @@ static int br_ip6_multicast_query(struct net_bridge *br,
 		goto out;
 
 	max_delay *= br->multicast_last_member_count;
-	if (mp->mglist &&
+	if (mp->host_joined &&
 	    (timer_pending(&mp->timer) ?
 	     time_after(mp->timer.expires, now + max_delay) :
 	     try_to_del_timer_sync(&mp->timer) >= 0))
@@ -1622,7 +1626,7 @@ br_multicast_leave_group(struct net_bridge *br,
 			br_mdb_notify(br->dev, port, group, RTM_DELMDB,
 				      p->flags);
 
-			if (!mp->ports && !mp->mglist &&
+			if (!mp->ports && !mp->host_joined &&
 			    netif_running(br->dev))
 				mod_timer(&mp->timer, jiffies);
 		}
@@ -1662,7 +1666,7 @@ br_multicast_leave_group(struct net_bridge *br,
 		     br->multicast_last_member_interval;
 
 	if (!port) {
-		if (mp->mglist &&
+		if (mp->host_joined &&
 		    (timer_pending(&mp->timer) ?
 		     time_after(mp->timer.expires, time) :
 		     try_to_del_timer_sync(&mp->timer) >= 0)) {

net/bridge/br_private.h

@@ -209,7 +209,7 @@ struct net_bridge_mdb_entry
 	struct rcu_head			rcu;
 	struct timer_list		timer;
 	struct br_ip			addr;
-	bool				mglist;
+	bool				host_joined;
 };
 
 struct net_bridge_mdb_htable

net/dsa/dsa_priv.h

@@ -147,10 +147,10 @@ int dsa_port_fdb_add(struct dsa_port *dp, const unsigned char *addr,
 int dsa_port_fdb_del(struct dsa_port *dp, const unsigned char *addr,
 		     u16 vid);
 int dsa_port_fdb_dump(struct dsa_port *dp, dsa_fdb_dump_cb_t *cb, void *data);
-int dsa_port_mdb_add(struct dsa_port *dp,
+int dsa_port_mdb_add(const struct dsa_port *dp,
 		     const struct switchdev_obj_port_mdb *mdb,
 		     struct switchdev_trans *trans);
-int dsa_port_mdb_del(struct dsa_port *dp,
+int dsa_port_mdb_del(const struct dsa_port *dp,
 		     const struct switchdev_obj_port_mdb *mdb);
 int dsa_port_vlan_add(struct dsa_port *dp,
 		      const struct switchdev_obj_port_vlan *vlan,

net/dsa/port.c

@@ -17,7 +17,7 @@
 
 #include "dsa_priv.h"
 
-static int dsa_port_notify(struct dsa_port *dp, unsigned long e, void *v)
+static int dsa_port_notify(const struct dsa_port *dp, unsigned long e, void *v)
 {
 	struct raw_notifier_head *nh = &dp->ds->dst->nh;
 	int err;
@@ -215,7 +215,7 @@ int dsa_port_fdb_dump(struct dsa_port *dp, dsa_fdb_dump_cb_t *cb, void *data)
 	return ds->ops->port_fdb_dump(ds, port, cb, data);
 }
 
-int dsa_port_mdb_add(struct dsa_port *dp,
+int dsa_port_mdb_add(const struct dsa_port *dp,
 		     const struct switchdev_obj_port_mdb *mdb,
 		     struct switchdev_trans *trans)
 {
@@ -229,7 +229,7 @@ int dsa_port_mdb_add(struct dsa_port *dp,
 	return dsa_port_notify(dp, DSA_NOTIFIER_MDB_ADD, &info);
 }
 
-int dsa_port_mdb_del(struct dsa_port *dp,
+int dsa_port_mdb_del(const struct dsa_port *dp,
 		     const struct switchdev_obj_port_mdb *mdb)
 {
 	struct dsa_notifier_mdb_info info = {

net/dsa/slave.c

@@ -304,6 +304,13 @@ static int dsa_slave_port_obj_add(struct net_device *dev,
 	case SWITCHDEV_OBJ_ID_PORT_MDB:
 		err = dsa_port_mdb_add(dp, SWITCHDEV_OBJ_PORT_MDB(obj), trans);
 		break;
+	case SWITCHDEV_OBJ_ID_HOST_MDB:
+		/* DSA can directly translate this to a normal MDB add,
+		 * but on the CPU port.
+		 */
+		err = dsa_port_mdb_add(dp->cpu_dp, SWITCHDEV_OBJ_PORT_MDB(obj),
+				       trans);
+		break;
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
 		err = dsa_port_vlan_add(dp, SWITCHDEV_OBJ_PORT_VLAN(obj),
 					trans);
@@ -326,6 +333,12 @@ static int dsa_slave_port_obj_del(struct net_device *dev,
 	case SWITCHDEV_OBJ_ID_PORT_MDB:
 		err = dsa_port_mdb_del(dp, SWITCHDEV_OBJ_PORT_MDB(obj));
 		break;
+	case SWITCHDEV_OBJ_ID_HOST_MDB:
+		/* DSA can directly translate this to a normal MDB add,
+		 * but on the CPU port.
+		 */
+		err = dsa_port_mdb_del(dp->cpu_dp, SWITCHDEV_OBJ_PORT_MDB(obj));
+		break;
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
 		err = dsa_port_vlan_del(dp, SWITCHDEV_OBJ_PORT_VLAN(obj));
 		break;

net/dsa/switch.c

@@ -121,7 +121,7 @@ static int dsa_switch_mdb_add(struct dsa_switch *ds,
 	if (ds->index == info->sw_index)
 		set_bit(info->port, group);
 	for (port = 0; port < ds->num_ports; port++)
-		if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))
+		if (dsa_is_dsa_port(ds, port))
 			set_bit(port, group);
 
 	if (switchdev_trans_ph_prepare(trans)) {

net/switchdev/switchdev.c

@@ -345,6 +345,8 @@ static size_t switchdev_obj_size(const struct switchdev_obj *obj)
 		return sizeof(struct switchdev_obj_port_vlan);
 	case SWITCHDEV_OBJ_ID_PORT_MDB:
 		return sizeof(struct switchdev_obj_port_mdb);
+	case SWITCHDEV_OBJ_ID_HOST_MDB:
+		return sizeof(struct switchdev_obj_port_mdb);
 	default:
 		BUG();
 	}