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From: Jason Wang <jasowang@redhat.com>
To: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>,
	qemu devel <qemu-devel@nongnu.org>
Cc: zhanghailiang <zhang.zhanghailiang@huawei.com>,
	Li Zhijian <lizhijian@cn.fujitsu.com>,
	Gui jianfeng <guijianfeng@cn.fujitsu.com>,
	"eddie.dong" <eddie.dong@intel.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	Yang Hongyang <hongyang.yang@easystack.cn>
Subject: Re: [Qemu-devel] [PATCH] net/filter-redirector:Add filter-redirector
Date: Mon, 29 Feb 2016 15:11:11 +0800	[thread overview]
Message-ID: <56D3EF0F.6040306@redhat.com> (raw)
In-Reply-To: <56CD71DD.6040900@cn.fujitsu.com>



On 02/24/2016 05:03 PM, Zhang Chen wrote:
>
> If queue=rx, filter-redirector will get the packet that guest send,
> then redirect
> to outdev(if none, do nothing). but queue=rx/tx/all not related to
> indev. please
> look the flow chart below. queue=xxx just work for one
> way(filter->outdev).
>
>                               filter
>                                 +
>                                 |
>                                 |
>                redirector       |
>                 +-------------------------+
>                 |               |         |
>                 |               |         |
>                 |               |         |
>    indev +----------------+     +---------------->  outdev
>                 |         |               |
>                 |         |               |
>                 |         |               |
>                 +-------------------------+
>                           |
>                           |
>                           v
>                        filter
>
>                           |
>
>                           |
>
>                           v
>                        filter ........ filter ...... guest
>

This looks a violation on the assumption of current filter behavior. 
Each filter should only talk to the 'next' or 'prev' filter on the chain
(depends on the direction) or netdev when queue=rx or netdev's peer when
queue=tx.

And in fact there's subtle differences with your patch:

When queue='all' since you force nf->netdev as sender, direction is
NET_FILTER_DIRECTION_TX, the packet will be passed to 'next' filter on
the chain.
When queue='rx', direction is NET_FILTER_DIRECTION_RX, the packet will
be pass to 'prev' filter on the chain.

So as you can see, 'all' is ambiguous here. I think we should keep
current behavior by redirecting traffic to netdev when queue='rx'. For
queue='all', maybe we need redirect the traffic to both netdev and
netdev's peer.

  reply	other threads:[~2016-02-29  7:11 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-05  6:50 [Qemu-devel] [PATCH] net/filter-redirector:Add filter-redirector Zhang Chen
2016-02-18  2:41 ` Jason Wang
2016-02-18  7:50   ` Zhang Chen
2016-02-24  3:39     ` Jason Wang
2016-02-24  9:03       ` Zhang Chen
2016-02-29  7:11         ` Jason Wang [this message]
2016-02-29 12:33           ` Zhang Chen
2016-03-02  5:41             ` Jason Wang

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