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Date: Wed, 29 Jul 2015 09:48:14 -0400 (EDT)
From: Thomas Huth <thuth@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 00/12] For QEMU 2.5: Add a netfilter object
 and netbuffer filter
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To: Yang Hongyang <yanghy@cn.fujitsu.com>
Cc: zhang zhanghailiang <zhang.zhanghailiang@huawei.com>, jasowang@redhat.com, qemu-devel@nongnu.org, mrhines@linux.vnet.ibm.com, stefanha@redhat.com

On Wednesday, July 29, 2015 3:39:45 PM,
"Yang Hongyang" <yanghy@cn.fujitsu.com> wrote:
> 
> Hi Thomas,
> 
> On 07/29/2015 08:56 PM, Thomas Huth wrote:
> > On Wednesday, July 29, 2015 12:51:44 PM,
> > "Yang Hongyang" <yanghy@cn.fujitsu.com> wrote:
> >>
> >> I do not take this as v2 because the design of this has been changed,
> >> and code is rewritten. according to thread:
> >> http://lists.nongnu.org/archive/html/qemu-devel/2015-07/msg05445.html
> >>
> >> This patch add a new object netfilter, capture all network packets.
> >> Also implement a netbuffer based on this object.
> >> the "buffer" netfilter could be used by VM FT solutions like
> >> Macrocheckpointing, to buffer/release packets. Or to simulate
> >> packet delay.
> >>
> >> Usage:
> >>   -netdev tap,id=bn0
> >>   -netfilter buffer,id=f0,netdev=bn0,interval=1000
> >>   -device e1000,netdev=bn0
> >
> > What if I want to use multiple filters at once? Is there a way to
> > determine the order in which the filters are run through?
> 
> The filters are in an QTAILQ list, so it's order is what appears
> first will be first. for example:
>    -netfilter dump,...
>    -netfilter buffer,...
> 
> dump will be the first filter.
> 
> >
> >> dynamically add/remove netfilters:
> >>   netfilter_add buffer,id=f0,netdev=bn0,interval=1000
> >>   netfilter_del f0
> >
> > Same here ... let's assume there are already two filters - can I
> > somehow add a third filter inbetween the two?
> 
> It's not possiable in this series, but it can be supported later,
> we can add an order option to the netfilter, so that it can be
> the order whatever you want.

Ok, thanks for the clarification. You're right, that's something
that also can be added later if needed.

 Thomas