[Qemu-devel] Re: bug reports and suggestions

[Anthony Liguori <anthony@codemonkey.ws>]

On Sat, 06 May 2006 01:12:50 +0200, Oliver Gerlich wrote:

> Another interesting thing concerning networking: I use a little script to
> set up a bridge between eth0 and tap0; but I have give the new bridge
> interface (eg. br0) an IP address and such stuff, because eth0 doesn't
> work. This is with Linux 2.6, but I read that with Linux 2.4 it was not
> necessary to configure br0, as eth0 would still be accessible. Does anyone
> know why this changed? I think it would be much easier if an interface
> used in a bridge was still usable.

My networking script creates a bridge (initially with no physical device
attached).  My qemu-ifup always attaches the tap device to a bridge
specified by an environmental variable.  I can then manage these bridges
outside of qemu.

So far, I've added support for three "operations" on these bridges.  The
bridge is initially consider a private virtual lan.  You can then either
NAT the virtual lan or bridge the lan to a physical interface.  When
NAT'ing or using a private lan, it also launches a DHCPD instance to
provide local DHCP services.

So far, this is the best I've been able to come up with in terms of a
usuable method of managing virtual networking.  I've included a pointer to
the script (although please note, it probably won't work on any system
other than my own) for reference.

I really think that to do this properly would require another full project
(especially since there's so much overlap between Xen/qemu in this area).

http://qemu.codemonkey.ws/vlan-config

Regards,

Anthony Liguori

> Thanks,
> Oliver
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