On Wed, May 18, 2022 at 02:58:40AM +0200, Andrew Lunn wrote:
> It is possible to stack bridges on top of each other. Consider the
> following which makes use of an Ethernet switch:
>
> br1
> / \
> / \
> / \
> br0.11 wlan0
> |
> br0
> / | \
> p1 p2 p3
>
> br0 is offloaded to the switch. Above br0 is a vlan interface, for
> vlan 11. This vlan interface is then a slave of br1. br1 also has a
> wireless interface as a slave. This setup trunks wireless lan traffic
> over the copper network inside a VLAN.
>
> A frame received on p1 which is passed up to the bridge has the
> skb->offload_fwd_mark flag set to true, indicating that the switch has
> dealt with forwarding the frame out ports p2 and p3 as needed. This
> flag instructs the software bridge it does not need to pass the frame
> back down again. However, the flag is not getting reset when the frame
> is passed upwards. As a result br1 sees the flag, wrongly interprets
> it, and fails to forward the frame to wlan0.
>
> When passing a frame upwards, clear the flag. This is the Rx
> equivalent of br_switchdev_frame_unmark() in br_dev_xmit().
>
> Fixes: f1c2eddf4cb6 ("bridge: switchdev: Use an helper to clear forward mark")
> Signed-off-by: Andrew Lunn <andrew@xxxxxxx>
Reviewed-by: Ido Schimmel <idosch@xxxxxxxxxx>
Tested-by: Ido Schimmel <idosch@xxxxxxxxxx>
