Re: [Qemu-devel] [RFC PATCH v2 00/10] Add colo-proxy based on netfilter

[Wen Congyang <wency@cn.fujitsu.com>]

On 01/22/2016 01:33 PM, Jason Wang wrote:
> 
> 
> On 01/20/2016 06:34 PM, Wen Congyang wrote:
>> On 01/20/2016 06:03 PM, Jason Wang wrote:
>>>
>>> On 01/20/2016 05:49 PM, Wen Congyang wrote:
>>>> On 01/20/2016 05:20 PM, Jason Wang wrote:
>>>>> On 01/20/2016 03:44 PM, Wen Congyang wrote:
>>>>>>>> ...
>>>>>>>> -chardev socket,id=comparer0,host=ip_primary,port=X,server,nowait
>>>>>>>> -chardev socket,id=comparer1,host=ip_primary,port=Y,server,nowait
>>>>>>>> -chardev socket,id=mirrorer0,host=ip_primary,port=Z,server,nowait
>>>>>>>> -netdev tap,id=hn0
>>>>>>>> -traffic-mirrorer netdev=hn0,id=t0,indev=comparer0,outdev=mirrorer0
>>>>>>>> -colo-comparer primary_traffic=comparer0,secondary_traffic=comparer1
>>>>>>>> ...
>>>>>>>>
>>>>>>>> packet comparer compares the packets from two chardev: comparer0 and
>>>>>>>> comparer1.
>>>>>>>> traffic-mirrorer mirror tx to secondary node through chardev mirrorer0,
>>>>>>>> and mirror rx to packet comparer through chardev comparer0.
>>>>>>>>
>>>>>>>> In secondary node:
>>>>>>>>
>>>>>>>> ...
>>>>>>>> -chardev socket,id=redirector0,host=ip_primary,port=Y
>>>>>>>> -chardev socket,id=redirector1,host=ip_primary,port=Z
>>>>>>>> -netdev tap,id=hn0
>>>>>>>> -traffic-redirector netdev=hn0,id,r0,indev=redirector0,outdev=redirector1
>>>>>>>> -colo-rewriter netdev=hn0,id=c0
>>>>>>>> ...
>>>>>>>>
>>>>>>>> traffic-redirector redirect the rx traffic from primary node through
>>>>>>>> redirector0 and redirect the tx traffic to promary node through redirector1.
>>>>>>>> colo-rewriter rewrite seq number as a normal netfilter.
>>>>>> What are traffic-mirrorer and colo-comparer, traffic-redirector, colo-rewriter?
>>>>>> A netfilter driver?
>>>>> traffic-mirrorer/redirector is a type of netfilter that just
>>>>> mirror/redirect packets between netdev and chardev (just the mirror
>>>>> client/sever and redirect client/sever in the above graph)
>>>>> colo-rewriter is a type of netfilter that did ack/seq adjust (just the
>>>>> TCP rewriter in the above graph)
>>>>> colo-comparer is a thread object that did packet comparing (similar to
>>>>> "compare" in the above graph but not a netfiler)
>>>> Thanks. I have another question:
>>>> IIRC, both rx and tx packets walk through all netfilter objects in the same order.
>>>>
>>>> tx packet(sent to the guest): we want that redirector hanldes it first
>>>> rx packet(sent from the guest): we want that colo-rewriter handles it first
>>>> Change the order or use two traffic-redirectors?
>>>>
>>>> Thanks
>>>> Wen Congyang
>>> Interesting question.
>>>
>>> Two redirectors sounds ok or maybe we can go through rx filters in a
>>> reverse order?
>> netdev <---> filter1 <----> filter2 <----> .... <----> emulated device <----> guest
>> So I think we can go through rx filters in a reverse order. But it changes
>> the behavior. So I am not sure if we can do it.
> 
> I think we can. Both dump and buffer filter does not require strict
> order, so it's a good time and change to do this.

OK, we will do it.

Thanks
Wen Congyang

> 
>>
>> Thanks
>> Wen Congyang
>>
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