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

[Thomas Huth]

On 22/07/15 12:55, Yang Hongyang wrote:
> This patch add a net filter between network backend and NIC devices.
> All packets will pass by this filter.
> TODO:
>  multiqueue support.
>  plugin support.
> 
>               +--------------+       +-------------+
> +----------+  |    filter    |       |frontend(NIC)|
> | real     |  |              |       |             |
> | network  <--+backend       <-------+             |
> | backend  |  |         peer +-------> peer        |
> +----------+  +--------------+       +-------------+
> 
> Usage:
> -netdev tap,id=bn0  # you can use whatever backend as needed
> -netdev filter,id=f0,backend=bn0,plugin=dump
> -device e1000,netdev=f0

That's basically a neat idea... however, one question remains: Will
there be other filters beside the "dump" filter that you mentioned in
your example? Do you already have something in mind?

If not, I think this is likely not worth the effort - and we likely
should keep it simple and implement the dump option as suggested with my
patches instead.

> diff --git a/net/filter.c b/net/filter.c
> new file mode 100644
> index 0000000..006c64a
> --- /dev/null
> +++ b/net/filter.c
> @@ -0,0 +1,200 @@
> +/*
> + * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
> + * (a.k.a. Fault Tolerance or Continuous Replication)

This looks like a bad copy-n-paste comment... ?

> + * Copyright (c) 2015 HUAWEI TECHNOLOGIES CO., LTD.
> + * Copyright (c) 2015 FUJITSU LIMITED
> + * Copyright (c) 2015 Intel Corporation
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or
> + * later.  See the COPYING file in the top-level directory.
> + */
...

 Thomas