[lldp-devel] [PATCH 1/3] vdp22 filter interface support

Thomas-Mich Richter tmricht at linux.vnet.ibm.com
Wed Nov 27 09:55:17 UTC 2013


On 11/27/2013 08:05 AM, John Fastabend wrote:
> On 11/26/2013 1:23 AM, Thomas-Mich Richter wrote:
>> On 11/25/2013 10:55 PM, John Fastabend wrote:
>>> On 11/21/2013 01:26 AM, Thomas Richter wrote:
>>>> The VDP22 protocol allows the return of changed filter
......
>> John,
>>
>> I understand your concerns. You might have noticed:
>> I tried to submit a patch to update if_link.h file to include the new
>> structures and attributes IFLA_PORT_VSI_TYPE22 and IFLA_PORT_VSI_FILTER.
>> Dave Miller turned it down, he does not accept a define without usage.
>> I can follow him (a bit, after all its just a structure definition)
>> and that is the reason why I did not push it further.
>> IFLA_PORT_VSI_TYPE is not used either and he might decide to drop it
>> from the kernel if_link.h and then libvirtd vs lldpad communication
>> is broken.
>>
>> However as the code stands now, the only user of the new defines for the
>> attributes IFLA_PORT_VSI_TYPE22 and IFLA_PORT_VSI_FILTER is my test
>> program vdptest.c. Libvirtd is not updated to use VDP22 protocols (at the
>> moment, that will come later).
>> And both programs vdptest and lldpad will be built together, different
>> builds of lldpad and libvirtd does not cause problems.
> h> Libvirtd does not use the new
>> IFLA_PORT_VSI_TYPE22 and IFLA_PORT_VSI_FILTER attributes. Libvirtd
>> uses IFLA_VFINFO_LIST to transfer the mac/vlan information. (This design
>> decision was not mine, it was done before I joint this team).
>>
>> My ideas:
>> 1. Try my patch again. But I am unsure if we succeed. In fact Qbg is
>>     not very active (dead might be a better word). And why should kernel
>>     define something it does not use. This is a very strong point.
>>     And we do not know any hardware which supports Qbg22 to actually know
>>     if we have done it right.
> 
> Agreed this is a non-starter for me, really it just makes things worse.
> Adding interfaces to the kernel without users is bad practice. Further
> running the protocol in user space works just fine for most of the
> cases.
> 
>> 2. I work on a command line interface for vdp22. It idea is to use the
>>     lldptool to trigger commands to associate/de-associate VSIs. Once this
>>     works the customers (libvirtd, vdptest) could use this interface defined
>>     by lldpad. This would eliminate the external dependency on the kernel.
> 
> This seems the best path. If libvirtd, vdptest use this interface then
> we don't need to use the kernel netlink interface at all. We can support
> the draft version over netlink (at least until all users drop it) and
> the standard version over the lldpad interface. Any idea how much work
> this would be? My hope is not too much.

I have just started, I reckon about 5 days to get it fully functional.
I still have higher priority tasks for vxlan, but I might have something
end of next week. (I am off on a 3 day skiing vacation from Dec 9th)

Looks like we agreed on this as the other options are no goes for obvious
reasons.

And libvirtd could do with an update.

>> 3. Use the current libvirtd scheme of IFLA_VFINFO_LIST and extend it with
>>     a suitable structure to pass the 4 byte group id. For example (mis)use
>>     attribute ifla_vf_tx_rate. BTW we have discussed this before.
> 
> Yeah I remember. Misusing fields like this also seems like a hack
> though.
> 
>> 4. Or we could use the ifla_vf_mac, which contains space for 32 byte mac
>>     address and use the remaining bytes to store the group id. This is a
>>     real hack.
> 
> Yep, its a hack.
> 
>>
>> I will work on the remaining findings and will submit my patch again.
>> As said before, this gives me a chance to test it (in fact I have another
>> big patch waiting for you: ~100 automated test cases for evb22, ecp22, vdp22).
>> It should not break the currently released libvirtd/lldpad communication.
>>
> 
> Great! I like test code. I should fix up the tests I have here for
> various things and commit them as well.
> 
Will post it soon.

Thomas.

-- 
Thomas Richter, Dept 3250, IBM LTC Boeblingen, Data Center Networking
--
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