net: bridge: fdb: don't flush ext_learn entries

commit f2f3729fb65c5c2e6db234e6316b71a7bdc4b30b upstream.

When a user-space software manages fdb entries externally it should
set the ext_learn flag which marks the fdb entry as externally managed
and avoids expiring it (they're treated as static fdbs). Unfortunately
on events where fdb entries are flushed (STP down, netlink fdb flush
etc) these fdbs are also deleted automatically by the bridge. That in turn
causes trouble for the managing user-space software (e.g. in MLAG setups
we lose remote fdb entries on port flaps).
These entries are completely externally managed so we should avoid
automatically deleting them, the only exception are offloaded entries
(i.e. BR_FDB_ADDED_BY_EXT_LEARN + BR_FDB_OFFLOADED). They are flushed as
before.

Fixes: eb100e0e24a2 ("net: bridge: allow to add externally learned entries from user-space")
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 4877a0db16c66ae2620ec43cd946c100f7ec3b3f..a8fa622e2d9b42857f15c96a8cb12029796eeddc 100644 (file)
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -404,6 +404,8 @@ void br_fdb_delete_by_port(struct net_bridge *br,
 
                if (!do_all)
                        if (test_bit(BR_FDB_STATIC, &f->flags) ||
+                           (test_bit(BR_FDB_ADDED_BY_EXT_LEARN, &f->flags) &&
+                            !test_bit(BR_FDB_OFFLOADED, &f->flags)) ||
                            (vid && f->key.vlan_id != vid))
                                continue;