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

[Yang Hongyang]

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.