Re: [Qemu-devel] [PATCH 0/9] For QEMU 2.5: Add a net filter and a netbuffer plugin based on the filter

[Yang Hongyang <yanghy@cn.fujitsu.com>]

Hi,

   Thank you for the comment!

On 07/27/2015 06:32 PM, Daniel P. Berrange wrote:
> On Sun, Jul 26, 2015 at 10:13:55PM +0800, Yang Hongyang wrote:
[...]
>>> Which is a little verbose for 'netdev' option.
>>
>> It's just the name diffrence, using netfilter will be
>> -netfilter ... -netfilter ...
>>
>> using plugin=xxx will make us hard to extend the plugin params under existing
>> netdev design thus will needs lots of extra effort to archive our goal, but we
>> already have a simple way, do we? and do note that Daniel's concern was based
>> on my initial RFC patch, which has a usage about "plugin=xxx", this series
>> is totally different.
>
> The current -netdev / netdev_add/netdev_del interfaces have a fairly
> static view of the world. If you just want to setup filters at the
> time you setup the guest NIC that's fine, but if you want to be able
> to dynamically change the filters that are used, without altering
> the guest device or the real host backend, I think you're going to
> run into problems using -netdev. eg consider you have a pre-exisiting
> guest running and you want to add in a 'dump' filter to temporarily
> record traffic to a file, without having any impact on guest
> connectivity. I'm not seeing how you could achieve that with the
> proposed netdev approach, because you'd basically have to delete the
> existing NIC and add a new one from scratch.

We will modify the NIC's peer when using netdev_add to add the filter.
The current netdev_add/netdev_del can be used while guest is running.
just to make sure netdev's init/cleanup can do the right thing.

>
> Regards,
> Daniel
>

-- 
Thanks,
Yang.