Re: [Qemu-devel] tun/tap networking: patch for existing tun

[Henrik Nordstrom]

On Mon, 3 Oct 2005, Jim C. Brown wrote:

> One potential issue is that the vde code is under the GPL, while qemu (at
> least the part that we're talking about) is under the BSD license.

Not really. None of the VDE code is needed to connect to VDE. The protocol 
used for VDE connection management is dead simple.

> The macaddr sets the mac address of the guest nic that qemu provides. I do
> not know if it is possible to set a tap device's mac address on creation
> but if it is possible then I agree that it would be a useful parameter.

It is, but defenitely overkill for builtin to QEMU. If you need special 
MACs on the host side then use persistent TUN/TAP devices and set the MAC 
from the host side.

If you use dynamic TUN/TAP devices then the script used for configuring 
the host side of the newly created TUN/TAP interface can also set the MAC 
address if desired. This you can do today without changing a single line 
of QEMU.

> The parameters that we choose to pass to the script will be a separate issue.
> My vote is qemu-ifup tapname macaddr (with macaddr being what was specified
> on the -net command line or the appropriate default).

Note: This MAC addr will be the MAC that QEMU is using, not the MAC the 
TUN/TAP device should be configured to. Only use of passing this to the 
script is if your script needs to add firewalling restricting which MACs 
QEMU is allowed to use, but in such case you are most likely better using 
a persistent TUN/TAP device anyway with no need of this script..

Regards
Henrik