Re: [Qemu-devel] WiFi inside VMs?

["Васил Рангелов" <boen.robot@gmail.com>]

Hi.

A USB/PCI device that is passed through to the VM would get a real WiFi inside a VM, but doing THAT would place the VM in a *real* wireless network.

The problem is that's not the goal.

The goal is to introduce a WiFi into a *virtual* wireless network, i.e. a WiFi network between this VM and other VMs that have virtual WiFi adapters. The network itself would be managed outside of Qemu (by GNS3), but Qemu needs to provide support for a virtual device that would send/receive data (to/from GNS3, which would then forward it over the UDP tunnel to the appropriate peers).

To quote the documentation:

````
There are two parts to networking within QEMU: 
## the virtual network device that is provided to the guest (e.g. a PCI network card). 
## the network backend that interacts with the emulated NIC (e.g. puts packets onto the host's network).
````

When using USB/PCI passthrough, you're using the real device as BOTH the backend and the device being provided to the guest.

But the goal is for the UDP tunnel backend to be used, so that frames can be "trapped" in the virtual network.

Currently, only Ethernet cards can use a UDP tunnel.

What I'm asking for is for at least one model of WiFi network card to be provided as a virtual device, and be able to use the UDP tunnel backend, even if it can't use any other backend.


-----Original Message-----
From: Nikolay Nikolaev [mailto:n.nikolaev@virtualopensystems.com] 
Sent: Thursday, October 2, 2014 10:42 PM
To: Васил Рангелов
Cc: qemu-devel
Subject: Re: [Qemu-devel] WiFi inside VMs?

Hello,

On Thu, Oct 2, 2014 at 10:14 PM, Васил Рангелов <boen.robot@gmail.com> wrote:
> Hello.
>
> I'd like to ask if it would be possible to add support for at least 
> one model of WiFi device on guest machines?

USB and/or PCI passthorugh might help here, or am I getting something wrong?

>
>
> I realize the feature request has been discussed previously (here:
> http://lists.nongnu.org/archive/html/qemu-devel/2007-03/msg00575.html 
> ), but my reason for wanting it is slightly different than the reason back then...
>
> There's this program for simulating networks you've definitely heard 
> of (I mean... It's been mentioned on this list...) - GNS3. It 
> currently can't emulate Wireless networks, exactly because Qemu (nor 
> any other emulator for that matter) supports WiFi devices inside VMs.
>
> The old discussion above points out how it would be problematic to 
> bridge a real WiFi adapter to the virtual one, but as far as GNS3 is 
> concerned, that's not really a problem, since the backend in its case 
> needs to be a UDP tunnel. As long as the WiFi frames can be 
> encapsulated into a UDP tunnel,
> GNS3 could theoretically provide the connection between two WiFi 
> devices inside a simulated topology.
>
>
> Even if such a feature's usefulness is only limited to GNS3, that's 
> still IMHO a great deal of usefulness, and therefore it should be a 
> worthy goal to pursue.
>
> So... Pleeeease? Pretty please? :-)
>
> Thanks,
> Regards,
> Vasil Rangelov
>
>

regards,
Nikolay Nikolaev
Virtual Open Systems