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

[Varlese, Marco]

> -----Original Message-----
> From: John Fastabend [mailto:john.fastabend@xxxxxxxxx]
> Sent: Wednesday, December 10, 2014 5:04 PM
> To: Jiri Pirko
> Cc: Varlese, Marco; netdev@xxxxxxxxxxxxxxx;
> stephen@xxxxxxxxxxxxxxxxxx; Fastabend, John R;
> roopa@xxxxxxxxxxxxxxxxxxx; sfeldma@xxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [RFC PATCH net-next 1/1] net: Support for switch port
> configuration
> 
> On 12/10/2014 08:50 AM, Jiri Pirko wrote:
> > Wed, Dec 10, 2014 at 05:23:40PM CET, marco.varlese@xxxxxxxxx wrote:
> >> From: Marco Varlese <marco.varlese@xxxxxxxxx>
> >>
> >> Switch hardware offers a list of attributes that are configurable on
> >> a per port basis.
> >> This patch provides a mechanism to configure switch ports by adding
> >> an NDO for setting specific values to specific attributes.
> >> There will be a separate patch that extends iproute2 to call the new
> >> NDO.
> >
> >
> > What are these attributes? Can you give some examples. I'm asking
> > because there is a plan to pass generic attributes to switch ports
> > replacing current specific ndo_switch_port_stp_update. In this case,
> > bridge is setting that attribute.
> >
> > Is there need to set something directly from userspace or does it make
> > rather sense to use involved bridge/ovs/bond ? I think that both will
> > be needed.
> 
> +1
> 
> I think for many attributes it would be best to have both. The in kernel callers
> and netlink userspace can use the same driver ndo_ops.
> 
> But then we don't _require_ any specific bridge/ovs/etc module. And we
> may have some attributes that are not specific to any existing software
> module. I'm guessing Marco has some examples of these.
> 
> [...]
> 
> 
> --
> John Fastabend         Intel Corporation

We do have a need to configure the attributes directly from user-space and I have identified the tool to do that in iproute2.

An example of attributes are:
* enabling/disabling of learning of source addresses on a given port (you can imagine the attribute called LEARNING for example);
* internal loopback control (i.e. LOOPBACK) which will control how the flow of traffic behaves from the switch fabric towards an egress port;
* flooding for broadcast/multicast/unicast type of packets (i.e. BFLOODING, MFLOODING, UFLOODING);

Some attributes would be of the type enabled/disabled while other will allow specific values to allow the user to configure different behaviours of that feature on that particular port on that platform.

One thing to mention - as John stated as well - there might be some attributes that are not specific to any software module but rather have to do with the actual hardware/platform to configure.

I hope this clarifies some points.

-----------------------------------------------------------
Marco Varlese		-	Intel Corporation
-----------------------------------------------------------


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