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

[Wen Congyang]

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

> 
>>
>> If not, how to get the packet from the netdev, and send back the packet to
>> the netdev?
>>
>> Thanks
>> Wen Congyang
>>
> 
> 
> 
> .
>