target/linux/generic/pending-5.4/767-net-dsa-Sync-static-FDB-entries-on-foreign-interface.patch

From 81e39fd78db82fb51b05fff309b9c521f1a0bc5a Mon Sep 17 00:00:00 2001
From: Tobias Waldekranz <tobias@waldekranz.com>
Date: Sat, 16 Jan 2021 02:25:14 +0100
Subject: [PATCH] net: dsa: Sync static FDB entries on foreign interfaces to
 hardware

Reuse the "assisted_learning_on_cpu_port" functionality to always add
entries for user-configured entries on foreign interfaces, even if
assisted_learning_on_cpu_port is not enabled. E.g. in this situation:

   br0
   / \
swp0 dummy0

$ bridge fdb add 02:00:de:ad:00:01 dev dummy0 vlan 1 master

Results in DSA adding an entry in the hardware FDB, pointing this
address towards the CPU port.

The same is true for entries added to the bridge itself, e.g:

$ bridge fdb add 02:00:de:ad:00:01 dev br0 vlan 1 self

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 net/dsa/slave.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -1703,9 +1703,12 @@ static int dsa_slave_switchdev_event(str
 			else if (!fdb_info->added_by_user)
 				return NOTIFY_OK;
 		} else {
-			/* Snoop addresses learnt on foreign interfaces
-			 * bridged with us, for switches that don't
-			 * automatically learn SA from CPU-injected traffic
+			/* Snoop addresses added to foreign interfaces
+			 * bridged with us, or the bridge
+			 * itself. Dynamically learned addresses can
+			 * also be added for switches that don't
+			 * automatically learn SA from CPU-injected
+			 * traffic.
 			 */
 			struct net_device *br_dev;
 			struct dsa_slave_priv *p;
@@ -1727,7 +1730,8 @@ static int dsa_slave_switchdev_event(str
 
 			dp = p->dp->cpu_dp;
 
-			if (!dp->ds->assisted_learning_on_cpu_port)
+			if (!fdb_info->added_by_user &&
+			    !dp->ds->assisted_learning_on_cpu_port)
 				return NOTIFY_DONE;
 		}