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

[Varlese, Marco]

> -----Original Message-----
> From: netdev-owner@xxxxxxxxxxxxxxx [mailto:netdev-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Jiri Pirko
> Sent: Thursday, December 11, 2014 1:09 PM
> To: Varlese, Marco
> Cc: John Fastabend; 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
> 
> Thu, Dec 11, 2014 at 01:02:36PM CET, marco.varlese@xxxxxxxxx wrote:
> >> -----Original Message-----
> >> From: Jiri Pirko [mailto:jiri@xxxxxxxxxxx]
> >> Sent: Thursday, December 11, 2014 11:01 AM
> >> To: Varlese, Marco
> >> Cc: John Fastabend; 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
> >>
> >> Thu, Dec 11, 2014 at 10:59:42AM CET, marco.varlese@xxxxxxxxx wrote:
> >> >> -----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.
> >>
> >> It does. Makes sense. We need to expose this attr set/get for both
> >> in-kernel and userspace use cases.
> >>
> >> Please adjust you patch for this. Also, as a second patch, it would
> >> be great if you can convert ndo_switch_port_stp_update to this new ndo.
> >>
> >> Thanks.
> >>
> >>
> >
> >I was thinking of leaving the get side of things implemented via sysfs rather
> than implementing an NDO for it. Would this not be appropriate?
> 
> I believe that it is preferred to have both get and set exposed via ndo and
> netlink. It can be exposed via sysfs as well, but it is "nice to have"
> not "must have"
> 

I'll add the get ndo to my patch now. Thanks.
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