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

[Jiri Pirko <jiri@resnulli.us>]

Thu, Dec 11, 2014 at 05:37:46PM CET, roopa@cumulusnetworks.com wrote:
>On 12/11/14, 3:01 AM, Jiri Pirko wrote:
>>Thu, Dec 11, 2014 at 10:59:42AM CET, marco.varlese@intel.com wrote:
>>>>-----Original Message-----
>>>>From: John Fastabend [mailto:john.fastabend@gmail.com]
>>>>Sent: Wednesday, December 10, 2014 5:04 PM
>>>>To: Jiri Pirko
>>>>Cc: Varlese, Marco; netdev@vger.kernel.org;
>>>>stephen@networkplumber.org; Fastabend, John R;
>>>>roopa@cumulusnetworks.com; sfeldma@gmail.com; linux-
>>>>kernel@vger.kernel.org
>>>>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@intel.com wrote:
>>>>>>From: Marco Varlese <marco.varlese@intel.com>
>>>>>>
>>>>>>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.

Yes, but that is for PF_BRIDGE and bridge specific attributes. There
might be another generic attrs, no?

>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

Yes, this might become handy for other generic non-bridge attrs.

>
>Thanks,
>Roopa
>
>
>