[ovs-dev] [patch net-next v2 8/9] switchdev: introduce Netlink API

Jiri Pirko jiri at resnulli.us
Sat Sep 20 08:25:29 UTC 2014


Sat, Sep 20, 2014 at 07:39:51AM CEST, f.fainelli at gmail.com wrote:
>On 09/19/14 15:18, Jamal Hadi Salim wrote:
>>On 09/19/14 18:12, John Fastabend wrote:
>>>On 09/19/2014 10:57 AM, Jamal Hadi Salim wrote:
>>>>On 09/19/14 11:49, Jiri Pirko wrote:
>>>>>Fri, Sep 19, 2014 at 05:25:48PM CEST, jhs at mojatatu.com wrote:
>>>>
>>>>>>Is this just a temporary test tool? Otherwise i dont see reason
>>>>>>for its existence (or the API that it feeds on).
>>>>>
>>>>>Please read the conversation I had with Pravin and Jesse in v1 thread.
>>>>>Long story short they like to have the api separated from ovs datapath
>>>>>so ovs daemon can use it to directly communicate with driver. Also John
>>>>>Fastabend requested a way to work with driver flows without using
>>>>>ovs ->
>>>>>that was the original reason I created switchdev genl api.
>>>>>
>>>>>Regarding the "sw" tool, yes it is for testing purposes now. ovs daemon
>>>>>will use directly switchdev genl api.
>>>>>
>>>>>I hope I cleared this out.
>>>>>
>>>>
>>>>It is - thanks Jiri.
>>>>
>>>>cheers,
>>>>jamal
>>>
>>>Hi Jiri,
>>>
>>>I was considering a slightly different approach where the
>>>device would report via netlink the fields/actions it
>>>supported rather than creating pre-defined enums for every
>>>possible key.
>>>
>>>I already need to have an API to report fields/matches
>>>that are being supported why not have the device report
>>>the headers as header fields (len, offset) and the
>>>associated parse graph the hardware uses? Vendors should
>>>have this already to describe/design their real hardware.
>>>
>>>As always its better to have code and when I get some
>>>time I'll try to write it up. Maybe its just a separate
>>>classifier although I don't actually want two hardware
>>>flow APIs.
>>>
>>>I see you dropped the RFC tag are you proposing we include
>>>this now?
>>>
>>
>>
>>Actually I just realized i missed something very basic that
>>Jiri said. I think i understand the tool being there for testing
>>but i am assumed the same about the genlink api.
>>Jiri, are you saying that genlink api is there to
>>stay?
>
>So, I really have mixed feelings about this netlink API, in particular
>because it is not clear to me where is the line between what should be a
>network device ndo operation, what should be an ethtool command, what should
>be a netlink message, and the rest.

Well as I said, this api should serve for flow manipulation only,
therefore swdev flow related ndos are used.


>
>I can certainly acknowledge the fact that manipulating flows is not ideal
>with the current set of tools, but really once we are there with netlink, how
>far are we from not having any network devices at all, and how does that
>differ from OpenWrt's swconfig in the end [1]?


I'm all ears on proposals how to make flow manipulation better.


>
>[1]: https://lwn.net/Articles/571390/
>--
>Florian



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