net: bridge: sync fdb to new unicast-filtering ports

Since commit 2796d0c648c9 ("bridge: Automatically manage
port promiscuous mode.")
bridges with `vlan_filtering 1` and only 1 auto-port don't
set IFF_PROMISC for unicast-filtering-capable ports.

Normally on port changes `br_manage_promisc` is called to
update the promisc flags and unicast filters if necessary,
but it cannot distinguish between *new* ports and ones
losing their promisc flag, and new ports end up not
receiving the MAC address list.

Fix this by calling `br_fdb_sync_static` in `br_add_if`
after the port promisc flags are updated and the unicast
filter was supposed to have been filled.

Fixes: 2796d0c648c9 ("bridge: Automatically manage port promiscuous mode.")
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index f7d2f472ae24f1160ad05e1da8604cee347a82f0..6e4a32354a138f96c96055ddbc2f25351b7fb945 100644 (file)
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -562,7 +562,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev,
        struct net_bridge_port *p;
        int err = 0;
        unsigned br_hr, dev_hr;
-       bool changed_addr;
+       bool changed_addr, fdb_synced = false;
 
        /* Don't allow bridging non-ethernet like devices. */
        if ((dev->flags & IFF_LOOPBACK) ||
@@ -652,6 +652,19 @@ int br_add_if(struct net_bridge *br, struct net_device *dev,
        list_add_rcu(&p->list, &br->port_list);
 
        nbp_update_port_count(br);
+       if (!br_promisc_port(p) && (p->dev->priv_flags & IFF_UNICAST_FLT)) {
+               /* When updating the port count we also update all ports'
+                * promiscuous mode.
+                * A port leaving promiscuous mode normally gets the bridge's
+                * fdb synced to the unicast filter (if supported), however,
+                * `br_port_clear_promisc` does not distinguish between
+                * non-promiscuous ports and *new* ports, so we need to
+                * sync explicitly here.
+                */
+               fdb_synced = br_fdb_sync_static(br, p) == 0;
+               if (!fdb_synced)
+                       netdev_err(dev, "failed to sync bridge static fdb addresses to this port\n");
+       }
 
        netdev_update_features(br->dev);
 
@@ -701,6 +714,8 @@ int br_add_if(struct net_bridge *br, struct net_device *dev,
        return 0;
 
 err7:
+       if (fdb_synced)
+               br_fdb_unsync_static(br, p);
        list_del_rcu(&p->list);
        br_fdb_delete_by_port(br, p, 0, 1);
        nbp_update_port_count(br);