Re: [PATCH v5 net-next 6/6] selftests: forwarding: add test of MAC-Auth Bypass to locked port tests

netdev
2022-08-29T08:02:53Z

On 2022-08-29 09:40, Ido Schimmel wrote:
> On Sun, Aug 28, 2022 at 02:00:29PM +0200, netdev@kapio-technology.com
> wrote:
>> On 2022-08-27 20:21, Ido Schimmel wrote:
>> > On Fri, Aug 26, 2022 at 01:45:38PM +0200, Hans Schultz wrote:
>> > > +locked_port_mab()
>> > > +{
>> > > + RET=0
>> > > + check_locked_port_support || return 0
>> > > +
>> > > + ping_do $h1 192.0.2.2
>> > > + check_err $? "MAB: Ping did not work before locking port"
>> > > +
>> > > + bridge link set dev $swp1 locked on
>> > > + bridge link set dev $swp1 learning on
>> >
>> > "locked on learning on" is counter intuitive and IMO very much a
>> > misconfiguration that we should have disallowed when the "locked" option
>> > was introduced. It is my understanding that the only reason we are even
>> > talking about it is because mv88e6xxx needs it for MAB for some reason.
>>
>> As the way mv88e6xxx implements "learning off" is to remove port
>> association
>> for ingress packets on a port, but that breaks many other things such
>> as
>> refreshing ATU entries and violation interrupts, so it is needed and
>> the
>> question is then what is the worst to have 'learning on' on a locked
>> port or
>> to have the locked port enabling learning in the driver silently?
>>
>> Opinions seem to differ. Note that even on locked ports without MAB,
>> port
>> association on ingress is still needed in future as I have a dynamic
>> ATU
>> patch set coming, that uses age out violation and hardware refreshing
>> to let
>> the hardware keep the dynamic entries as long as the authorized
>> station is
>> sending, but will age the entry out if the station keeps silent for
>> the
>> ageing time. But that patch set is dependent on this patch set, and I
>> don't
>> think I can send it before this is accepted...
>
> Can you explain how you envision user space to work once everything is
> merged? I want to make sure we have the full picture before more stuff
> is merged. From what you describe, I expect the following:
>
> 1. Create topology, assuming two unauthorized ports:
>
> # ip link add name br0 type bridge no_linklocal_learn 1 (*)
> # ip link set dev swp1 master br0
> # ip link set dev swp2 master br0
> # bridge link set dev swp1 learning on locked on
> # bridge link set dev swp2 learning on locked on

The final decision on this rests with you I would say. Actually I forgot
to remove the port association in the driver in this version.

> # ip link set dev swp1 up
> # ip link set dev swp2 up
> # ip link set dev br0 up
>
> 2. Assuming h1 behind swp1 was authorized using 802.1X:
>
> # bridge fdb replace $H1_MAC dev swp1 master dynamic

With the new MAB flag 'replace' is not needed when MAB is not enabled.

>
> 3. Assuming 802.1X authentication failed for h2 behind swp2, enable
> MAB:
>
> # bridge link set dev swp2 mab on
>
> 4. Assuming $H2_MAC is in our allow list:
>
> # bridge fdb replace $H2_MAC dev swp2 master dynamic
>
> Learning is on in order to refresh the dynamic entries that user space
> installed.

Yes, port association is needed for those reasons. :-)

>
> (*) Need to add support for this option in iproute2. Already exposed
> over netlink (see 'IFLA_BR_MULTI_BOOLOPT').

Should I do that in this patch set?