Re: [dpdk-dev] [PATCH / RFC] kni: Add set_rx_mode callback to handle multicast groups

["Zhang, Helin" <helin.zhang@intel.com>]

> -----Original Message-----
> From: Simon Kågström [mailto:simon.kagstrom@netinsight.net]
> Sent: Tuesday, June 2, 2015 1:44 PM
> To: Zhang, Helin; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH / RFC] kni: Add set_rx_mode callback to handle
> multicast groups
> 
> On 2015-06-02 05:44, Zhang, Helin wrote:
> >> -----Original Message-----
> >> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Simon Kagstrom
> >> Sent: Thursday, May 7, 2015 9:18 PM
> >> To: dev@dpdk.org
> >> Subject: [dpdk-dev] [PATCH / RFC] kni: Add set_rx_mode callback to
> >> handle multicast groups
> >>
> >> This is needed to add / remove interfaces in multicast groups via the ip tool.
> > Could you help to explain with more details of why it is needed?
> 
> We did some (very basic) tests with IGMP, which involves adding multicast
> addresses to ETH interfaces. This is done via the ip tool, an example can be found
> on e.g.,
> 
> 
> http://superuser.com/questions/324824/linux-built-in-or-open-source-program-
> to-join-multicast-group
> 
> and this will fail on KNI interfaces with the current code because of an
> unimplemented ioctl (as Stephen Hemminger said earlier). The patch simply adds
> an empty callback so that the ioctl succeeds, and this is the same thing as the
> Linux tap interface does (so I think it should be enough for KNI as well).
Yes, the root cause "null ioctl causes the failure" should be added in the commit log
for future reference by others.
I am OK for the reason, please add the details to the commit logs.

Thanks,
Helin

> 
> 
> If you want, I can update the patch with a bit more description (something like
> the above).


> 
> // Simon