net: bridge: mcast: re-implement br_multicast_{enable, disable}_port functions

When a bridge port STP state is changed from BLOCKING/DISABLED to
FORWARDING, the port's igmp query timer will NOT re-arm itself if the
bridge has been configured as per-VLAN multicast snooping.

Solve this by choosing the correct multicast context(s) to enable/disable
port multicast based on whether per-VLAN multicast snooping is enabled or
not, i.e. using per-{port, VLAN} context in case of per-VLAN multicast
snooping by re-implementing br_multicast_enable_port() and
br_multicast_disable_port() functions.

Before the patch, the IGMP query does not happen in the last step of the
following test sequence, i.e. no growth for tx counter:
 # ip link add name br1 up type bridge vlan_filtering 1 mcast_snooping 1 mcast_vlan_snooping 1 mcast_querier 1 mcast_stats_enabled 1
 # bridge vlan global set vid 1 dev br1 mcast_snooping 1 mcast_querier 1 mcast_query_interval 100 mcast_startup_query_count 0
 # ip link add name swp1 up master br1 type dummy
 # bridge link set dev swp1 state 0
 # ip -j -p stats show dev swp1 group xstats_slave subgroup bridge suite mcast | jq '.[]["multicast"]["igmp_queries"]["tx_v2"]'
1
 # sleep 1
 # ip -j -p stats show dev swp1 group xstats_slave subgroup bridge suite mcast | jq '.[]["multicast"]["igmp_queries"]["tx_v2"]'
1
 # bridge link set dev swp1 state 3
 # sleep 2
 # ip -j -p stats show dev swp1 group xstats_slave subgroup bridge suite mcast | jq '.[]["multicast"]["igmp_queries"]["tx_v2"]'
1

After the patch, the IGMP query happens in the last step of the test:
 # ip link add name br1 up type bridge vlan_filtering 1 mcast_snooping 1 mcast_vlan_snooping 1 mcast_querier 1 mcast_stats_enabled 1
 # bridge vlan global set vid 1 dev br1 mcast_snooping 1 mcast_querier 1 mcast_query_interval 100 mcast_startup_query_count 0
 # ip link add name swp1 up master br1 type dummy
 # bridge link set dev swp1 state 0
 # ip -j -p stats show dev swp1 group xstats_slave subgroup bridge suite mcast | jq '.[]["multicast"]["igmp_queries"]["tx_v2"]'
1
 # sleep 1
 # ip -j -p stats show dev swp1 group xstats_slave subgroup bridge suite mcast | jq '.[]["multicast"]["igmp_queries"]["tx_v2"]'
1
 # bridge link set dev swp1 state 3
 # sleep 2
 # ip -j -p stats show dev swp1 group xstats_slave subgroup bridge suite mcast | jq '.[]["multicast"]["igmp_queries"]["tx_v2"]'
3

Signed-off-by: Yong Wang <yongwang@nvidia.com>
Reviewed-by: Andy Roulin <aroulin@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Yong Wang

net/bridge/br_multicast.c

@@ -2105,12 +2105,17 @@ static void __br_multicast_enable_port_ctx(struct net_bridge_mcast_port *pmctx)
 	}
 }
 
-void br_multicast_enable_port(struct net_bridge_port *port)
+static void br_multicast_enable_port_ctx(struct net_bridge_mcast_port *pmctx)
 {
-	struct net_bridge *br = port->br;
+	struct net_bridge *br = pmctx->port->br;
 
 	spin_lock_bh(&br->multicast_lock);
-	__br_multicast_enable_port_ctx(&port->multicast_ctx);
+	if (br_multicast_port_ctx_is_vlan(pmctx) &&
+	    !(pmctx->vlan->priv_flags & BR_VLFLAG_MCAST_ENABLED)) {
+		spin_unlock_bh(&br->multicast_lock);
+		return;
+	}
+	__br_multicast_enable_port_ctx(pmctx);
 	spin_unlock_bh(&br->multicast_lock);
 }
 
@@ -2137,11 +2142,67 @@ static void __br_multicast_disable_port_ctx(struct net_bridge_mcast_port *pmctx)
 	br_multicast_rport_del_notify(pmctx, del);
 }
 
+static void br_multicast_disable_port_ctx(struct net_bridge_mcast_port *pmctx)
+{
+	struct net_bridge *br = pmctx->port->br;
+
+	spin_lock_bh(&br->multicast_lock);
+	if (br_multicast_port_ctx_is_vlan(pmctx) &&
+	    !(pmctx->vlan->priv_flags & BR_VLFLAG_MCAST_ENABLED)) {
+		spin_unlock_bh(&br->multicast_lock);
+		return;
+	}
+
+	__br_multicast_disable_port_ctx(pmctx);
+	spin_unlock_bh(&br->multicast_lock);
+}
+
+static void br_multicast_toggle_port(struct net_bridge_port *port, bool on)
+{
+#if IS_ENABLED(CONFIG_BRIDGE_VLAN_FILTERING)
+	if (br_opt_get(port->br, BROPT_MCAST_VLAN_SNOOPING_ENABLED)) {
+		struct net_bridge_vlan_group *vg;
+		struct net_bridge_vlan *vlan;
+
+		rcu_read_lock();
+		vg = nbp_vlan_group_rcu(port);
+		if (!vg) {
+			rcu_read_unlock();
+			return;
+		}
+
+		/* iterate each vlan, toggle vlan multicast context */
+		list_for_each_entry_rcu(vlan, &vg->vlan_list, vlist) {
+			struct net_bridge_mcast_port *pmctx =
+						&vlan->port_mcast_ctx;
+			u8 state = br_vlan_get_state(vlan);
+			/* enable vlan multicast context when state is
+			 * LEARNING or FORWARDING
+			 */
+			if (on && br_vlan_state_allowed(state, true))
+				br_multicast_enable_port_ctx(pmctx);
+			else
+				br_multicast_disable_port_ctx(pmctx);
+		}
+		rcu_read_unlock();
+		return;
+	}
+#endif
+	/* toggle port multicast context when vlan snooping is disabled */
+	if (on)
+		br_multicast_enable_port_ctx(&port->multicast_ctx);
+	else
+		br_multicast_disable_port_ctx(&port->multicast_ctx);
+}
+
+void br_multicast_enable_port(struct net_bridge_port *port)
+{
+	br_multicast_toggle_port(port, true);
+}
+
 void br_multicast_disable_port(struct net_bridge_port *port)
 {
-	spin_lock_bh(&port->br->multicast_lock);
-	__br_multicast_disable_port_ctx(&port->multicast_ctx);
-	spin_unlock_bh(&port->br->multicast_lock);
+	br_multicast_toggle_port(port, false);
 }
 
 static int __grp_src_delete_marked(struct net_bridge_port_group *pg)
@@ -4304,9 +4365,9 @@ int br_multicast_toggle_vlan_snooping(struct net_bridge *br, bool on,
 		__br_multicast_open(&br->multicast_ctx);
 	list_for_each_entry(p, &br->port_list, list) {
 		if (on)
-			br_multicast_disable_port(p);
+			br_multicast_disable_port_ctx(&p->multicast_ctx);
 		else
-			br_multicast_enable_port(p);
+			br_multicast_enable_port_ctx(&p->multicast_ctx);
 	}
 
 	list_for_each_entry(vlan, &vg->vlan_list, vlist)