[systemd-devel] How to add a second bridge to a nspawn container?

[Andrei Borzenkov]

04.01.2019 6:23, Alexander E. Patrakov пишет:
>>
>> I am not sure whether "Operation not supported" means that there is something wrong with that config? or that it is not possible to create a bridge to a wireless NIC?
> 
> To be able to participate in a bridge, the wireless card must act as
> an access point. This restriction comes from the fact that, generally,
> there are 4 MAC addresses that one needs to be concerned about: Access
> Point, Station, Source and Destination, but a wireless packet can
> contain only three distinct ones. Being an access point helps, because
> one knows that there are no bridges on the far end, i.e. all incoming
> packets have Station = Source, and all outgoing packets except
> multicast have Station = Destination.
> 

Actually wireless packet has space for 4 MAC addresses, this is how WDS
works. Depending on wireless adapter and driver it may be possible to
set 4addr mode. But this most likely requires special explicit
configuration on AP side to allow WDS from specific MAC. Good overview
is here: http://nullroute.eu.org/~grawity/journal-2011.html#post:20110826