Re: [RFC PATCH net-next 1/1] net: Support for switch port configuration

[Thomas Graf <tgraf@suug.ch>]

On 12/15/14 at 02:29pm, Varlese, Marco wrote:
> > All of these are highly generic and should *not* be passed through from user
> > space to the driver directly but rather be properly abstracted as Roopa
> > proposed. The value of this API is abstraction.
> How would you let the user enable/disable features then? For instance, how would the user enable/disable flooding for broadcast packets (BFLOODING) on a given port? What I was proposing is to have a list of attributes (to be added in if_link.h) which can be tuned by the user using a tool like iproute2. What do you propose? 

Excellent, I agree with what you are saying. What set me off is that
the patch does not reflect that yet. Instead, the patch introduces
a pure Netlink pass-through API to the driver.

I would expect the patch to:
 1. Parse the Netlink messages and be aware of individual attributes
 2. Validate them
 3. Pass the configuration to the driver using an API that can also
    be consumed from in-kernel users.

> I think I have seen Roopa posting his updated ndo patch and getting some feedback by few people already and as long as I will be able to accomplish the use case described here I am happy with his way.

I think Roopa's patches are supplementary. Not all switchdev users
will be backed with a Linux Bridge. I therefore welcome your patches
very much.

The overlap is in the ndo. I think both the API you propose and
Roopa's bridge code should use the same NDO.

> I do not have an example right now of a vendor specific attribute but I was just saying that might happen (i.e. someone will have a feature not implemented by others?).

That's fine. Once we have them we can consider adding vendor specific
extensions.