Re: [PATCH v4 net-next 3/6] drivers: net: dsa: add locked fdb entry flag to drivers

netdev
2022-08-12T12:29:56Z

On 2022-08-11 13:28, Ido Schimmel wrote:

>> > I'm talking about roaming, not forwarding. Let's say you have a locked
>> > entry with MAC X pointing to port Y. Now you get a packet with SMAC X
>> > from port Z which is unlocked. Will the FDB entry roam to port Z? I
>> > think it should, but at least in current implementation it seems that
>> > the "locked" flag will not be reset and having locked entries pointing
>> > to an unlocked port looks like a bug.
>> >
>>

In general I have been thinking that the said setup is a network
configuration error as I was arguing in an earlier conversation with
Vladimir. In this setup we must remember that SMAC X becomes DMAC X in
the return traffic on the open port. But the question arises to me why
MAC X would be behind the locked port without getting authed while being
behind an open port too?
In a real life setup, I don't think you would want random hosts behind a
locked port in the MAB case, but only the hosts you will let through.
Other hosts should be regarded as intruders.

If we are talking about a station move, then the locked entry will age
out and MAC X will function normally on the open port after the timeout,
which was a case that was taken up in earlier discussions.

But I will anyhow do some testing with this 'edge case' (of being behind
both a locked and an unlocked port) if I may call it so, and see to that
the offloaded and non-offloaded cases correspond to each other, and will
work satisfactory.

I think it will be good to have a flag to enable the mac-auth/MAB
feature, and I suggest just calling the flag 'mab', as it is short.

Otherwise I don't see any major issues with the whole feature as it is.