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

[Roopa Prabhu]

On 12/11/14, 3:01 AM, Jiri Pirko wrote:
> 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.

Why are we exposing generic switch attribute get/set from userspace ?. 
We already have specific attributes for learning/flooding which can be 
extended further.
And for in kernel api....i had a sample patch in my RFC series (Which i 
was going to resubmit, until it was decided that we will use existing 
api around ndo_bridge_setlink/ndo_bridge_getlink):
http://www.spinics.net/lists/netdev/msg305473.html

Thanks,
Roopa



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