net: bridge: add option to allow activity notifications for any fdb entries

This patch adds the ability to notify about activity of any entries
(static, permanent or ext_learn). EVPN multihoming peers need it to
properly and efficiently handle mac sync (peer active/locally active).
We add a new NFEA_ACTIVITY_NOTIFY attribute which is used to dump the
current activity state and to control if static entries should be monitored
at all. We use 2 bits - one to activate fdb entry tracking (disabled by
default) and the second to denote that an entry is inactive. We need
the second bit in order to avoid multiple notifications of inactivity.
Obviously this makes no difference for dynamic entries since at the time
of inactivity they get deleted, while the tracked non-dynamic entries get
the inactive bit set and get a notification.

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

1 files changed, 11 insertions, 0 deletions

diff --git a/include/uapi/linux/neighbour.h b/include/uapi/linux/neighbour.h
index 540ff48402a1..21e569297355 100644
--- a/include/uapi/linux/neighbour.h
+++ b/include/uapi/linux/neighbour.h
@@ -173,13 +173,24 @@ enum {
 };
 #define NDTA_MAX (__NDTA_MAX - 1)
 
+ /* FDB activity notification bits used in NFEA_ACTIVITY_NOTIFY:
+  * - FDB_NOTIFY_BIT - notify on activity/expire for any entry
+  * - FDB_NOTIFY_INACTIVE_BIT - mark as inactive to avoid multiple notifications
+  */
+enum {
+	FDB_NOTIFY_BIT		= (1 << 0),
+	FDB_NOTIFY_INACTIVE_BIT	= (1 << 1)
+};
+
 /* embedded into NDA_FDB_EXT_ATTRS:
  * [NDA_FDB_EXT_ATTRS] = {
+ *     [NFEA_ACTIVITY_NOTIFY]
  *     ...
  * }
  */
 enum {
 	NFEA_UNSPEC,
+	NFEA_ACTIVITY_NOTIFY,
 	__NFEA_MAX
 };
 #define NFEA_MAX (__NFEA_MAX - 1)