Re: [Qemu-devel] A QEMU net driver for OpenVPN's Tap-Win32 driver

Re: [Qemu-devel] A QEMU net driver for OpenVPN's Tap-Win32 driver

[John Poplett]

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Hi, all

Here is a patch that allows qemu to interface with OpenVPN's Tap-Win32
driver on windows. This provides an alternative to slirp and allows a guest
OS to appear as though it is directly connected to a LAN.

I have tested it by bridging OpenVPN's Tap-Win32 adapter with an Ethernet
adapter using Windows XP's software network bridge. It gets about 4Mbytes
bandwidth in either direction, tested with iperf on my 2.4 GHz P4. My test
environment consists of Windows XP (host), Slackware 10 (guest) and the 2.0 
beta 11 version of the Tap-Win32 driver. I have
not tested this code against ppc or sparc.

Most of the work was done by a friend who wishes to remain anonymous. I have
contributed the semaphore code, benchmarking and other minor tweaks.

The patch adds a new, win32 specific command line option: -tap adapter. 
"adapter" should be the name of an installed Tap-Win32 driver.

Here is an example command line using the new option:

qemu.exe -L %QEMU_HOME%\. -tap tap -m 128 -boot c -hda slackware-10-x86.img

John

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[Qemu-devel] A QEMU net driver for OpenVPN's Tap-Win32 driver

[John Poplett]

Hi, all

I'm looking at what it would take to create a QEMU net driver to interface 
with OpenVN's Tap-Win32 driver. So far it looks fairly straightforward to 
do. colinux interfaces to Tap-Win32 already. Has anyone else looked into 
this?

John 

Re: [Qemu-devel] A QEMU net driver for OpenVPN's Tap-Win32 driver

[Mike Tremoulet]

John --

I had looked into this only very slightly.  My thoughts were to use
libpcap/libnet to essentially be a generic network adapter that could
take over any network device, with the goal of using that to
read/write from a TAP driver.  I'm not sure how the libpcap vs.
winpcap API lines up, and I think (not 100% sure) that winpcap can
write to the device as well, but that was the idea.  A command line
switch could specify which network device to control, so I could
concievably run multiple QEMUs with multiple TAP devices.

I spent a week hunting down the networking code in QEMU (hey, I
haven't done *that* much C programming lately) and then, well, life
got busy.  I'd love to see this added, though, as it seems much more
stable than the SLIRP in place today.

-- Mike


On Wed, 29 Sep 2004 20:47:32 -0500, John Poplett
<john.poplett@comcast.net> wrote:
> Hi, all
> 
> I'm looking at what it would take to create a QEMU net driver to interface
> with OpenVN's Tap-Win32 driver. So far it looks fairly straightforward to
> do. colinux interfaces to Tap-Win32 already. Has anyone else looked into
> this?
> 
> John
> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
>

Re: [Qemu-devel] A QEMU net driver for OpenVPN's Tap-Win32 driver

[John Poplett]

Hi, Mike

Another developer sent me a patch recently that looks promising. It is based 
on the user-mode code in openvpn and works with the Tap-Win32 driver. I am 
out of town for a few days and have some more coding to do when I get back 
but will keep you posted.

Regards,

John

----- Original Message ----- 
From: "Mike Tremoulet" <coffeemike@gmail.com>
To: "John Poplett" <jpoplett@acm.org>; <qemu-devel@nongnu.org>
Sent: Sunday, October 03, 2004 11:59 AM
Subject: Re: [Qemu-devel] A QEMU net driver for OpenVPN's Tap-Win32 driver


> John --
>
> I had looked into this only very slightly.  My thoughts were to use
> libpcap/libnet to essentially be a generic network adapter that could
> take over any network device, with the goal of using that to
> read/write from a TAP driver.  I'm not sure how the libpcap vs.
> winpcap API lines up, and I think (not 100% sure) that winpcap can
> write to the device as well, but that was the idea.  A command line
> switch could specify which network device to control, so I could
> concievably run multiple QEMUs with multiple TAP devices.
>
> I spent a week hunting down the networking code in QEMU (hey, I
> haven't done *that* much C programming lately) and then, well, life
> got busy.  I'd love to see this added, though, as it seems much more
> stable than the SLIRP in place today.
>
> -- Mike
>
>
> On Wed, 29 Sep 2004 20:47:32 -0500, John Poplett
> <john.poplett@comcast.net> wrote:
>> Hi, all
>>
>> I'm looking at what it would take to create a QEMU net driver to 
>> interface
>> with OpenVN's Tap-Win32 driver. So far it looks fairly straightforward to
>> do. colinux interfaces to Tap-Win32 already. Has anyone else looked into
>> this?
>>
>> John
>>
>> _______________________________________________
>> Qemu-devel mailing list
>> Qemu-devel@nongnu.org
>> http://lists.nongnu.org/mailman/listinfo/qemu-devel
>>
>
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