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

netdev
2022-09-28T07:32:20Z

On 2022-09-28 08:59, Ido Schimmel wrote:
> Sorry for the delay, was away.

Good to have you back. :-)

>
> On Tue, Sep 27, 2022 at 10:33:10AM +0200, netdev@kapio-technology.com
> wrote:
>> On 2022-09-21 09:15, Ido Schimmel wrote:
>> > bridge fdb add `mac_get $h2` dev br0 blackhole
>>
>> To make this work, I think we need to change the concept, so that
>> blackhole
>> FDB entries are added to ports connected to the bridge, thus
>> bridge fdb add MAC dev $swpX master blackhole
>>
>> This makes sense as the driver adds them based on the port where the
>> SMAC is
>> seen, even though the effect of the blackhole FDB entry is switch
>> wide.
>
> Asking user space to associate a blackhole entry with a bridge port
> does
> not make sense to me because unlike regular entries, blackhole entries
> do not forward packets out of this port. Blackhole routes and nexthops
> are not associated with a device either.
>
>> Adding them to the bridge (e.g. f.ex. br0) will not work in the SW
>> bridge as
>> the entries then are not found.
>
> Why not found? This works:
>
> # bridge fdb add 00:11:22:33:44:55 dev br0 self local
> $ bridge fdb get 00:11:22:33:44:55 br br0
> 00:11:22:33:44:55 dev br0 master br0 permanent
>
> With blackhole support I expect:
>
> # bridge fdb add 00:11:22:33:44:55 dev br0 self local blackhole
> $ bridge fdb get 00:11:22:33:44:55 br br0
> 00:11:22:33:44:55 dev br0 master br0 permanent blackhole

In my previous replies, I have notified that fdb_find_rcu() does not
find the entry added with br0, and thus fdb_add_entry() that does the
replace does not replace but adds a new entry. I have been thinking that
it is because when added with br0 as dev it is added to dev br0's fdb,
which is not the same as 'dev <Dev> master' fdb...

I think bridge fdb get works in a different way, as I know the get
functionality gets all fdb entries from all devices and filters them (if
I am not mistaken)...