Linux Virtualization - Apr 2018 - [RFC PATCH 2/3] netdev: kernel-only IFF_HIDDEN netdevice

> Networking vendors have out of tree kernel modules. Those modules use a
> netdev (call it a master netdev, a control netdev, cpu port, whatever)
> to pull packets from the ASIC and deliver to virtual netdevices
> representing physical ports.
Sounds a lot like DSA. Please ask the vendor to contribute the drivers
:-)
> The master netdev should not be mucked with by a user. It should be
> ignored by certain s/w with lldpd as just an *example*.
I have come across occasional problems with the master device in DSA.
But nothing too serious. Generally the switch will just toss frames it
gets which don't have the needed header, when they come direct from
the master device, rather than via the slave devices.

    Andrew