[Bridge] [PATCH net-next 2/6] net: bridge: fdb: add support for fine-grained flushing

[Nikolay Aleksandrov <razor@blackwall.org>]

Add the ability to specify exactly which fdbs to be flushed. They are
described by a new structure - net_bridge_fdb_flush_desc. Currently it
can match on port/bridge ifindex, vlan id and fdb flags. It is used to
describe the existing dynamic fdb flush operation.

Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
---
 net/bridge/br_fdb.c      | 36 +++++++++++++++++++++++++++++-------
 net/bridge/br_netlink.c  |  9 +++++++--
 net/bridge/br_private.h  | 10 +++++++++-
 net/bridge/br_sysfs_br.c |  6 +++++-
 4 files changed, 50 insertions(+), 11 deletions(-)

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 6ccda68bd473..4b0bf88c4121 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -558,18 +558,40 @@ void br_fdb_cleanup(struct work_struct *work)
 	mod_delayed_work(system_long_wq, &br->gc_work, work_delay);
 }
 
-/* Completely flush all dynamic entries in forwarding database.*/
-void br_fdb_flush(struct net_bridge *br)
+static bool __fdb_flush_matches(const struct net_bridge *br,
+				const struct net_bridge_fdb_entry *f,
+				const struct net_bridge_fdb_flush_desc *desc)
+{
+	const struct net_bridge_port *dst = READ_ONCE(f->dst);
+	int port_ifidx, br_ifidx = br->dev->ifindex;
+
+	port_ifidx = dst ? dst->dev->ifindex : 0;
+
+	return (!desc->vlan_id || desc->vlan_id == f->key.vlan_id) &&
+	       (!desc->port_ifindex ||
+		(desc->port_ifindex == port_ifidx ||
+		 (!dst && desc->port_ifindex == br_ifidx))) &&
+	       (!desc->flags_mask ||
+		((f->flags & desc->flags_mask) == desc->flags));
+}
+
+/* Flush forwarding database entries matching the description */
+void br_fdb_flush(struct net_bridge *br,
+		  const struct net_bridge_fdb_flush_desc *desc)
 {
 	struct net_bridge_fdb_entry *f;
-	struct hlist_node *tmp;
 
-	spin_lock_bh(&br->hash_lock);
-	hlist_for_each_entry_safe(f, tmp, &br->fdb_list, fdb_node) {
-		if (!test_bit(BR_FDB_STATIC, &f->flags))
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(f, &br->fdb_list, fdb_node) {
+		if (!__fdb_flush_matches(br, f, desc))
+			continue;
+
+		spin_lock_bh(&br->hash_lock);
+		if (!hlist_unhashed(&f->fdb_node))
 			fdb_delete(br, f, true);
+		spin_unlock_bh(&br->hash_lock);
 	}
-	spin_unlock_bh(&br->hash_lock);
+	rcu_read_unlock();
 }
 
 /* Flush all entries referring to a specific port.
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index fe2211d4c0c7..6e6dce6880c9 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -1366,8 +1366,13 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 		br_recalculate_fwd_mask(br);
 	}
 
-	if (data[IFLA_BR_FDB_FLUSH])
-		br_fdb_flush(br);
+	if (data[IFLA_BR_FDB_FLUSH]) {
+		struct net_bridge_fdb_flush_desc desc = {
+			.flags_mask = BR_FDB_STATIC
+		};
+
+		br_fdb_flush(br, &desc);
+	}
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 	if (data[IFLA_BR_MCAST_ROUTER]) {
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 6e62af2e07e9..e6930e9ee69d 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -274,6 +274,13 @@ struct net_bridge_fdb_entry {
 	struct rcu_head			rcu;
 };
 
+struct net_bridge_fdb_flush_desc {
+	unsigned long			flags;
+	unsigned long			flags_mask;
+	int				port_ifindex;
+	u16				vlan_id;
+};
+
 #define MDB_PG_FLAGS_PERMANENT	BIT(0)
 #define MDB_PG_FLAGS_OFFLOAD	BIT(1)
 #define MDB_PG_FLAGS_FAST_LEAVE	BIT(2)
@@ -759,7 +766,8 @@ int br_fdb_init(void);
 void br_fdb_fini(void);
 int br_fdb_hash_init(struct net_bridge *br);
 void br_fdb_hash_fini(struct net_bridge *br);
-void br_fdb_flush(struct net_bridge *br);
+void br_fdb_flush(struct net_bridge *br,
+		  const struct net_bridge_fdb_flush_desc *desc);
 void br_fdb_find_delete_local(struct net_bridge *br,
 			      const struct net_bridge_port *p,
 			      const unsigned char *addr, u16 vid);
diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
index 3f7ca88c2aa3..612e367fff20 100644
--- a/net/bridge/br_sysfs_br.c
+++ b/net/bridge/br_sysfs_br.c
@@ -344,7 +344,11 @@ static DEVICE_ATTR_RW(group_addr);
 static int set_flush(struct net_bridge *br, unsigned long val,
 		     struct netlink_ext_ack *extack)
 {
-	br_fdb_flush(br);
+	struct net_bridge_fdb_flush_desc desc = {
+		.flags_mask = BR_FDB_STATIC
+	};
+
+	br_fdb_flush(br, &desc);
 	return 0;
 }
 
-- 
2.35.1