Re: [PATCH v8 net-next 10/12] net: dsa: mv88e6xxx: mac-auth/MAB implementation

netdev
2022-10-21T13:17:33Z

On 2022-10-21 13:22, Vladimir Oltean wrote:
> On Fri, Oct 21, 2022 at 08:47:42AM +0200, netdev@kapio-technology.com
> wrote:
>> On 2022-10-21 00:57, Vladimir Oltean wrote:
>> > On Thu, Oct 20, 2022 at 10:20:50PM +0200, netdev@kapio-technology.com
>> > wrote:
>> > > In general locked ports block traffic from a host based on if there
>> > > is a
>> > > FDB entry or not. In the non-offloaded case, there is only CPU
>> > > assisted
>> > > learning, so the normal learning mechanism has to be disabled as any
>> > > learned entry will open the port for the learned MAC,vlan.
>> >
>> > Does it have to be that way? Why can't BR_LEARNING on a BR_PORT_LOCKED
>> > cause the learned FDB entries to have BR_FDB_LOCKED, and everything
>> > would be ok in that case (the port will not be opened for the learned
>> > MAC/VLAN)?
>>
>> I suppose you are right that basing it solely on BR_FDB_LOCKED is
>> possible.
>>
>> The question is then maybe if the common case where you don't need
>> learned
>> entries for the scheme to work, e.g. with EAPOL link local packets,
>> requires
>> less CPU load to work and is cleaner than if using BR_FDB_LOCKED
>> entries?
>
> I suppose the real question is what does the bridge currently do with
> BR_LEARNING + BR_PORT_LOCKED, and if that is sane and useful in any
> case?
> It isn't a configuration that's rejected, for sure. The configuration
> could be rejected via a bug fix patch, then in net-next it could be
> made
> to learn these addresses with the BR_FDB_LOCKED flag.
>
> To your question regarding the common case (no MAB): that can be
> supported
> just fine when BR_LEARNING is off and BR_PORT_LOCKED is on, no?
> No BR_FDB_LOCKED entries will be learned.

As it is now in the bridge, the locked port part is handled before
learning
in the ingress data path, so with BR_LEARNING and BR_PORT_LOCKED, I
think it
will work as it does now except link local packages.

If your suggestion of BR_LEARNING causing BR_FDB_LOCKED on a locked
port, I
guess it would be implemented under br_fdb_update() and BR_LEARNING +
BR_PORT_LOCKED would go together, forcing BR_LEARNING in this case, thus
also
for all drivers?