net: bridge: Add support for notifying devices about FDB add/del

Currently the bridge doesn't notify the underlying devices about new
FDBs learned. The FDB sync is placed on the switchdev notifier chain
because devices may potentially learn FDB that are not directly related
to their ports, for example:

1. Mixed SW/HW bridge - FDBs that point to the ASICs external devices
                        should be offloaded as CPU traps in order to
			perform forwarding in slow path.
2. EVPN - Externally learned FDBs for the vtep device.

Notification is sent only about static FDB add/del. This is done due
to fact that currently this is the only scenario supported by switch
drivers.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Reviewed-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 44 insertions, 2 deletions

diff --git a/net/bridge/br.c b/net/bridge/br.c
index e962fff..96d209c 100644
--- a/net/bridge/br.c
+++ b/net/bridge/br.c
@@ -138,14 +138,14 @@ static int br_switchdev_event(struct notifier_block *unused,
 	br = p->br;
 
 	switch (event) {
-	case SWITCHDEV_FDB_ADD:
+	case SWITCHDEV_FDB_ADD_TO_BRIDGE:
 		fdb_info = ptr;
 		err = br_fdb_external_learn_add(br, p, fdb_info->addr,
 						fdb_info->vid);
 		if (err)
 			err = notifier_from_errno(err);
 		break;
-	case SWITCHDEV_FDB_DEL:
+	case SWITCHDEV_FDB_DEL_TO_BRIDGE:
 		fdb_info = ptr;
 		err = br_fdb_external_learn_del(br, p, fdb_info->addr,
 						fdb_info->vid);
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 5c780cd..26a1dae 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -690,6 +690,8 @@ static void fdb_notify(struct net_bridge *br,
 	struct sk_buff *skb;
 	int err = -ENOBUFS;
 
+	br_switchdev_fdb_notify(fdb, type);
+
 	skb = nlmsg_new(fdb_nlmsg_size(), GFP_ATOMIC);
 	if (skb == NULL)
 		goto errout;
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index a122684..98410ea 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -1085,6 +1085,8 @@ bool nbp_switchdev_allowed_egress(const struct net_bridge_port *p,
 int br_switchdev_set_port_flag(struct net_bridge_port *p,
 			       unsigned long flags,
 			       unsigned long mask);
+void br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb,
+			     int type);
 #else
 static inline int nbp_switchdev_mark_set(struct net_bridge_port *p)
 {
@@ -1108,6 +1110,11 @@ static inline int br_switchdev_set_port_flag(struct net_bridge_port *p,
 {
 	return 0;
 }
+
+static inline void
+br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb, int type)
+{
+}
 #endif /* CONFIG_NET_SWITCHDEV */
 
 #endif
diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
index b975959..181a44d 100644
--- a/net/bridge/br_switchdev.c
+++ b/net/bridge/br_switchdev.c
@@ -98,3 +98,36 @@ int br_switchdev_set_port_flag(struct net_bridge_port *p,
 
 	return 0;
 }
+
+static void
+br_switchdev_fdb_call_notifiers(bool adding, const unsigned char *mac,
+				u16 vid, struct net_device *dev)
+{
+	struct switchdev_notifier_fdb_info info;
+	unsigned long notifier_type;
+
+	info.addr = mac;
+	info.vid = vid;
+	notifier_type = adding ? SWITCHDEV_FDB_ADD_TO_DEVICE : SWITCHDEV_FDB_DEL_TO_DEVICE;
+	call_switchdev_notifiers(notifier_type, dev, &info.info);
+}
+
+void
+br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb, int type)
+{
+	if (!fdb->added_by_user)
+		return;
+
+	switch (type) {
+	case RTM_DELNEIGH:
+		br_switchdev_fdb_call_notifiers(false, fdb->addr.addr,
+						fdb->vlan_id,
+						fdb->dst->dev);
+		break;
+	case RTM_NEWNEIGH:
+		br_switchdev_fdb_call_notifiers(true, fdb->addr.addr,
+						fdb->vlan_id,
+						fdb->dst->dev);
+		break;
+	}
+}