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

[netdev]

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.