net: bridge: multicast: add per-port EHT hosts limit

Add a default limit of 512 for number of tracked EHT hosts per-port.
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/bridge/br_multicast.c

@@ -1608,6 +1608,7 @@ static void br_mc_disabled_update(struct net_device *dev, bool value)
 int br_multicast_add_port(struct net_bridge_port *port)
 {
 	port->multicast_router = MDB_RTR_TYPE_TEMP_QUERY;
+	port->multicast_eht_hosts_limit = BR_MCAST_DEFAULT_EHT_HOSTS_LIMIT;
 
 	timer_setup(&port->multicast_router_timer,
 		    br_multicast_router_expired, 0);

net/bridge/br_multicast_eht.c

@@ -127,6 +127,8 @@ static void __eht_destroy_host(struct net_bridge_group_eht_host *eht_host)
 {
 	WARN_ON(!hlist_empty(&eht_host->set_entries));
 
+	br_multicast_eht_hosts_dec(eht_host->pg);
+
 	rb_erase(&eht_host->rb_node, &eht_host->pg->eht_host_tree);
 	RB_CLEAR_NODE(&eht_host->rb_node);
 	kfree(eht_host);
@@ -257,6 +259,9 @@ __eht_lookup_create_host(struct net_bridge_port_group *pg,
 			return this;
 	}
 
+	if (br_multicast_eht_hosts_over_limit(pg))
+		return NULL;
+
 	eht_host = kzalloc(sizeof(*eht_host), GFP_ATOMIC);
 	if (!eht_host)
 		return NULL;
@@ -269,6 +274,8 @@ __eht_lookup_create_host(struct net_bridge_port_group *pg,
 	rb_link_node(&eht_host->rb_node, parent, link);
 	rb_insert_color(&eht_host->rb_node, &pg->eht_host_tree);
 
+	br_multicast_eht_hosts_inc(pg);
+
 	return eht_host;
 }
 

net/bridge/br_private.h

@@ -310,6 +310,8 @@ struct net_bridge_port {
 #if IS_ENABLED(CONFIG_IPV6)
 	struct bridge_mcast_own_query	ip6_own_query;
 #endif /* IS_ENABLED(CONFIG_IPV6) */
+	u32				multicast_eht_hosts_limit;
+	u32				multicast_eht_hosts_cnt;
 	unsigned char			multicast_router;
 	struct bridge_mcast_stats	__percpu *mcast_stats;
 	struct timer_list		multicast_router_timer;

net/bridge/br_private_mcast_eht.h

@@ -4,6 +4,8 @@
 #ifndef _BR_PRIVATE_MCAST_EHT_H_
 #define _BR_PRIVATE_MCAST_EHT_H_
 
+#define BR_MCAST_DEFAULT_EHT_HOSTS_LIMIT 512
+
 union net_bridge_eht_addr {
 	__be32				ip4;
 #if IS_ENABLED(CONFIG_IPV6)
@@ -47,6 +49,7 @@ struct net_bridge_group_eht_set {
 	struct net_bridge_mcast_gc	mcast_gc;
 };
 
+#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 void br_multicast_eht_clean_sets(struct net_bridge_port_group *pg);
 bool br_multicast_eht_handle(struct net_bridge_port_group *pg,
 			     void *h_addr,
@@ -62,4 +65,27 @@ br_multicast_eht_should_del_pg(const struct net_bridge_port_group *pg)
 		  RB_EMPTY_ROOT(&pg->eht_host_tree));
 }
 
+static inline bool
+br_multicast_eht_hosts_over_limit(const struct net_bridge_port_group *pg)
+{
+	const struct net_bridge_port *p = pg->key.port;
+
+	return !!(p->multicast_eht_hosts_cnt >= p->multicast_eht_hosts_limit);
+}
+
+static inline void br_multicast_eht_hosts_inc(struct net_bridge_port_group *pg)
+{
+	struct net_bridge_port *p = pg->key.port;
+
+	p->multicast_eht_hosts_cnt++;
+}
+
+static inline void br_multicast_eht_hosts_dec(struct net_bridge_port_group *pg)
+{
+	struct net_bridge_port *p = pg->key.port;
+
+	p->multicast_eht_hosts_cnt--;
+}
+#endif /* CONFIG_BRIDGE_IGMP_SNOOPING */
+
 #endif /* _BR_PRIVATE_MCAST_EHT_H_ */