netdev - Re: [RFC PATCH net-next 04/16] bridge: switchdev: Allow device drivers to install locked FDB entries

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Message-ID: <9dc0592e-04a0-bc92-0ced-a7d43f8a0016@blackwall.org>
Date:   Tue, 25 Oct 2022 14:03:48 +0300
From:   Nikolay Aleksandrov <razor@...ckwall.org>
To:     Ido Schimmel <idosch@...dia.com>, netdev@...r.kernel.org,
        bridge@...ts.linux-foundation.org
Cc:     davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
        edumazet@...gle.com, jiri@...dia.com, petrm@...dia.com,
        ivecera@...hat.com, roopa@...dia.com, netdev@...io-technology.com,
        vladimir.oltean@....com, mlxsw@...dia.com
Subject: Re: [RFC PATCH net-next 04/16] bridge: switchdev: Allow device
 drivers to install locked FDB entries

On 25/10/2022 13:00, Ido Schimmel wrote:
> From: "Hans J. Schultz" <netdev@...io-technology.com>
> 
> When the bridge is offloaded to hardware, FDB entries are learned and
> aged-out by the hardware. Some device drivers synchronize the hardware
> and software FDBs by generating switchdev events towards the bridge.
> 
> When a port is locked, the hardware must not learn autonomously, as
> otherwise any host will blindly gain authorization. Instead, the
> hardware should generate events regarding hosts that are trying to gain
> authorization and their MAC addresses should be notified by the device
> driver as locked FDB entries towards the bridge driver.
> 
> Allow device drivers to notify the bridge driver about such entries by
> extending the 'switchdev_notifier_fdb_info' structure with the 'locked'
> bit. The bit can only be set by device drivers and not by the bridge
> driver.
> 
> Prevent a locked entry from being installed if MAB is not enabled on the
> bridge port. By placing this check in the bridge driver we avoid the
> need to reflect the 'BR_PORT_MAB' flag to device drivers.
> 
> If an entry already exists in the bridge driver, reject the locked entry
> if the current entry does not have the "locked" flag set or if it points
> to a different port. The same semantics are implemented in the software
> data path.
> 
> Signed-off-by: Hans J. Schultz <netdev@...io-technology.com>
> Signed-off-by: Ido Schimmel <idosch@...dia.com>
> ---
> 
> Notes:
>     Changes made by me:
>     
>      * Reword commit message.
>      * Forbid locked entries when MAB is not enabled.
>      * Forbid roaming of locked entries.
>      * Avoid setting 'locked' bit towards device drivers.
> 
>  include/net/switchdev.h   |  1 +
>  net/bridge/br.c           |  3 ++-
>  net/bridge/br_fdb.c       | 22 ++++++++++++++++++++--
>  net/bridge/br_private.h   |  2 +-
>  net/bridge/br_switchdev.c |  1 +
>  5 files changed, 25 insertions(+), 4 deletions(-)
> 

Acked-by: Nikolay Aleksandrov <razor@...ckwall.org>