Re: [Qemu-devel] [PATCH] RFC/net: Add a net filter

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

On 07/28/2015 05:30 PM, Jason Wang wrote:
> On 07/28/2015 05:19 PM, Yang Hongyang wrote:
>> On 07/28/2015 12:00 PM, Yang Hongyang wrote:
>>> On 07/28/2015 11:28 AM, Jason Wang wrote:
>>>> On 07/27/2015 06:03 PM, Yang Hongyang wrote:
>>>>> On 07/27/2015 05:16 PM, Jason Wang wrote:
>>>>> [...]
>>>>>>>>>>> I think this won't work for the buffer case? If we want the
>>>>>>>>>>> buffer
>>>>>>>>>>> case
>>>>>>>>>>> to work under this, we should modify the generic netdev layer
>>>>>>>>>>> code, to
>>>>>>>>>>> check the return value of the filter function call.
>>>>>>>>>>
>>>>>>>>>> But checking return value is rather simpler than a new netdev
>>>>>>>>>> type,
>>>>>>>>>> isn't it?
>>>>>>>>>
>>>>>>>>> But how to implement a plugin which suppose to do the actual
>>>>>>>>> work on
>>>>>>>>> the packets?
>>>>>>>>
>>>>>>>> Well, the filter get the packets, so it can do everything it wants.
>>>>>>>>
>>>>>>>>> how to configure params related to the plugin? different
>>>>>>>>> plugins may need different params, implement as another netdev?
>>>>>>>>
>>>>>>>> I belive qmp can do this? something like -filter
>>>>>>>> dump,id=f0,len=10000?
>>>>>>>
>>>>>>> So you mean implement another object filter?
>>>>>>
>>>>>> Yes.
>>>>>>
>>>>>>> and the structure is like netdev?
>>>>>>
>>>>>> No, it is embedded in netdev.
>>>>>
>>>>> Ah, I see what you mean, thank you for the patience...
>>>>> does the command line looks like:
>>>>> -filter dump,id=f0,len=10000
>>>>> -netdev tap,XXX,filter=dump
>>>>>
>>>>> If I need both dump and packets buffering, how will the qmp be?
>>>>> -filter dump,id=f0,len=10000
>>>>> -filter buffer,XXX
>>>>> -netdev tap,XXX,filter=dump:buffer:XXX ?
>>>>
>>>> This is ok but we have several choices, e.g you may want to have a next
>>>> field like:
>>>>
>>>> - filter buffer,id=f0
>>>> - filter dump,id=f1,len=1000,next=f0
>>>> - netdev tap,XXX,filter_root=f1
>>>
>>> This seems better, thank you!
>>
>> Sorry, when try to implement it, I found this qmp is not that good
>> when it
>> comes to dynamically add/remove filters, can I use below instead:
>> -netdev tap,id=bn0
>> -netfilter dump,id=f0,netdev=bn0
>> -netfilter buffer,id=f1,netdev=bn0
>>
>> by this, I can introduce a QTAILQ of filters to NetClentState and
>> netdev_{add|del}_filter to dynamically add/remove filters.
>
> This looks good.

Thank you.

>
> Thanks
> .
>

-- 
Thanks,
Yang.