net: bridge: mcast: add support for blocked port groups

When excluding S,G entries we need a way to block a particular S,G,port.
The new port group flag is managed based on the source's timer as per
RFCs 3376 and 3810. When a source expires and its port group is in
EXCLUDE mode, it will be blocked.

Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/if_bridge.h

@@ -519,6 +519,7 @@ struct br_mdb_entry {
 #define MDB_FLAGS_OFFLOAD	(1 << 0)
 #define MDB_FLAGS_FAST_LEAVE	(1 << 1)
 #define MDB_FLAGS_STAR_EXCL	(1 << 2)
+#define MDB_FLAGS_BLOCKED	(1 << 3)
 	__u8 flags;
 	__u16 vid;
 	struct {

net/bridge/br_mdb.c

@@ -64,6 +64,8 @@ static void __mdb_entry_fill_flags(struct br_mdb_entry *e, unsigned char flags)
 		e->flags |= MDB_FLAGS_FAST_LEAVE;
 	if (flags & MDB_PG_FLAGS_STAR_EXCL)
 		e->flags |= MDB_FLAGS_STAR_EXCL;
+	if (flags & MDB_PG_FLAGS_BLOCKED)
+		e->flags |= MDB_FLAGS_BLOCKED;
 }
 
 static void __mdb_entry_to_br_ip(struct br_mdb_entry *entry, struct br_ip *ip,

net/bridge/br_multicast.c

@@ -72,7 +72,8 @@ __br_multicast_add_group(struct net_bridge *br,
 			 struct br_ip *group,
 			 const unsigned char *src,
 			 u8 filter_mode,
-			 bool igmpv2_mldv1);
+			 bool igmpv2_mldv1,
+			 bool blocked);
 static void br_multicast_find_del_pg(struct net_bridge *br,
 				     struct net_bridge_port_group *pg);
 
@@ -211,7 +212,7 @@ static void __fwd_add_star_excl(struct net_bridge_port_group *pg,
 		return;
 
 	src_pg = __br_multicast_add_group(br, pg->key.port, sg_ip, pg->eth_addr,
-					  MCAST_INCLUDE, false);
+					  MCAST_INCLUDE, false, false);
 	if (IS_ERR_OR_NULL(src_pg) ||
 	    src_pg->rt_protocol != RTPROT_KERNEL)
 		return;
@@ -343,7 +344,7 @@ void br_multicast_sg_add_exclude_ports(struct net_bridge_mdb_entry *star_mp,
 		src_pg = __br_multicast_add_group(br, pg->key.port,
 						  &sg->key.addr,
 						  sg->eth_addr,
-						  MCAST_INCLUDE, false);
+						  MCAST_INCLUDE, false, false);
 		if (IS_ERR_OR_NULL(src_pg) ||
 		    src_pg->rt_protocol != RTPROT_KERNEL)
 			continue;
@@ -364,7 +365,8 @@ static void br_multicast_fwd_src_add(struct net_bridge_group_src *src)
 	sg_ip = src->pg->key.addr;
 	sg_ip.src = src->addr.src;
 	sg = __br_multicast_add_group(src->br, src->pg->key.port, &sg_ip,
-				      src->pg->eth_addr, MCAST_INCLUDE, false);
+				      src->pg->eth_addr, MCAST_INCLUDE, false,
+				      !timer_pending(&src->timer));
 	if (IS_ERR_OR_NULL(sg))
 		return;
 	src->flags |= BR_SGRP_F_INSTALLED;
@@ -415,9 +417,38 @@ static void br_multicast_fwd_src_remove(struct net_bridge_group_src *src)
 	src->flags &= ~BR_SGRP_F_INSTALLED;
 }
 
+/* install S,G and based on src's timer enable or disable forwarding */
 static void br_multicast_fwd_src_handle(struct net_bridge_group_src *src)
 {
+	struct net_bridge_port_group_sg_key sg_key;
+	struct net_bridge_port_group *sg;
+	u8 old_flags;
+
 	br_multicast_fwd_src_add(src);
+
+	memset(&sg_key, 0, sizeof(sg_key));
+	sg_key.addr = src->pg->key.addr;
+	sg_key.addr.src = src->addr.src;
+	sg_key.port = src->pg->key.port;
+
+	sg = br_sg_port_find(src->br, &sg_key);
+	if (!sg || (sg->flags & MDB_PG_FLAGS_PERMANENT))
+		return;
+
+	old_flags = sg->flags;
+	if (timer_pending(&src->timer))
+		sg->flags &= ~MDB_PG_FLAGS_BLOCKED;
+	else
+		sg->flags |= MDB_PG_FLAGS_BLOCKED;
+
+	if (old_flags != sg->flags) {
+		struct net_bridge_mdb_entry *sg_mp;
+
+		sg_mp = br_mdb_ip_get(src->br, &sg_key.addr);
+		if (!sg_mp)
+			return;
+		br_mdb_notify(src->br->dev, sg_mp, sg, RTM_NEWMDB);
+	}
 }
 
 static void br_multicast_destroy_mdb_entry(struct net_bridge_mcast_gc *gc)
@@ -995,7 +1026,10 @@ static void br_multicast_group_src_expired(struct timer_list *t)
 		if (!hlist_empty(&pg->src_list))
 			goto out;
 		br_multicast_find_del_pg(br, pg);
+	} else {
+		br_multicast_fwd_src_handle(src);
 	}
+
 out:
 	spin_unlock(&br->multicast_lock);
 }
@@ -1131,7 +1165,8 @@ __br_multicast_add_group(struct net_bridge *br,
 			 struct br_ip *group,
 			 const unsigned char *src,
 			 u8 filter_mode,
-			 bool igmpv2_mldv1)
+			 bool igmpv2_mldv1,
+			 bool blocked)
 {
 	struct net_bridge_port_group __rcu **pp;
 	struct net_bridge_port_group *p = NULL;
@@ -1167,6 +1202,8 @@ __br_multicast_add_group(struct net_bridge *br,
 		goto out;
 	}
 	rcu_assign_pointer(*pp, p);
+	if (blocked)
+		p->flags |= MDB_PG_FLAGS_BLOCKED;
 	br_mdb_notify(br->dev, mp, p, RTM_NEWMDB);
 
 found:
@@ -1189,7 +1226,7 @@ static int br_multicast_add_group(struct net_bridge *br,
 
 	spin_lock(&br->multicast_lock);
 	pg = __br_multicast_add_group(br, port, group, src, filter_mode,
-				      igmpv2_mldv1);
+				      igmpv2_mldv1, false);
 	/* NULL is considered valid for host joined groups */
 	err = IS_ERR(pg) ? PTR_ERR(pg) : 0;
 	spin_unlock(&br->multicast_lock);

net/bridge/br_private.h

@@ -214,6 +214,7 @@ struct net_bridge_fdb_entry {
 #define MDB_PG_FLAGS_OFFLOAD	BIT(1)
 #define MDB_PG_FLAGS_FAST_LEAVE	BIT(2)
 #define MDB_PG_FLAGS_STAR_EXCL	BIT(3)
+#define MDB_PG_FLAGS_BLOCKED	BIT(4)
 
 #define PG_SRC_ENT_LIMIT	32