[Qemu-devel] Re: [PATCH 0/8] vlan cleanup

[Miguel Di Ciurcio Filho <miguel.filho@gmail.com>]

On Tue, Jul 13, 2010 at 3:16 AM, Jan Kiszka <jan.kiszka@web.de> wrote:
> Miguel Di Ciurcio Filho wrote:
>> This series removes the vlan stuff without mercy. I've tried to make the steps
>> as small as possible, but the last one is huge. I did some basic tests and
>> networking is still working, so reviews are welcome :-D
>
> Sorry, this is a bit too rude. This not only removes the vlan model,
> something one may talk about, but also the innocent socket back-ends and
> the useful pcap dump support.
>
> Socket back-ends allow quick and easy unprivileged inter-VM network
> setups. Nothing for production systems, but useful for testing purposes
> on boxes where taps are not allowed or unhandy to configure.
>

I agree that it might be handy sometimes, but one could use VDE for
that too. Runs on user-space and can be tunneled over SSH or netcat
[1].
Another option would be to make the socket backend properly work as a
netdev, so one could directly connect guest NICs on different hosts,
but on a 1:1 relationship.

> The dump client helps to debug user mode guest networks, namely slirp
> which you did not remove. If that should become the only use case for
> vlans with more than 2 nodes, we could think about making it a special
> feature of backend devices.
>

socket and dump are only used when the vlan backends are concerned, so
they don't have any useful meaning outside of that.

How about add dump hooks on backends? I don't think network backends
need to be stackable like block devices, thought.

> I'm open for cleanups here, but they do require a bit mercy - and should
> also mention the reason.
>

Well, basically there is a lot of "if (vlan) else if (peer)". While
discussing the query-netdev QMP command, no one has shown any love
about the vlan stuff at all, quite the contrary and it was kept out of
the protocol.

Regards,

Miguel

[1] http://wiki.virtualsquare.org/index.php/VDE#vde_plug