[Qemu-devel] Any interest in an option to use an existing tun/tap device?

[Qemu-devel] Any interest in an option to use an existing tun/tap device?

[Rob Browning]

It would be nice if qemu could be configured to use an existing
tun/tap device rather than require root (or sudo) access.  Would
others be interested in such an addition, perhaps "qemu -tun tun0" or
similar.

User Mode Linux allows something similar.  See the section "TUN/TAP
with a preconfigured tap device" at
http://user-mode-linux.sourceforge.net/networking.html.

Thanks
-- 
Rob Browning
rlb @defaultvalue.org and @debian.org; previously @cs.utexas.edu
GPG starting 2002-11-03 = 14DD 432F AE39 534D B592  F9A0 25C8 D377 8C7E 73A4

Re: [Qemu-devel] Any interest in an option to use an existing tun/tap device?

[Jesus M. Salvo Jr.]

Rob Browning wrote:

>It would be nice if qemu could be configured to use an existing
>tun/tap device rather than require root (or sudo) access.  Would
>others be interested in such an addition, perhaps "qemu -tun tun0" or
>similar.
>
>User Mode Linux allows something similar.  See the section "TUN/TAP
>with a preconfigured tap device" at
>http://user-mode-linux.sourceforge.net/networking.html.
>
>Thanks
>

I thought it already does, via the -tun-fd option ... though I have not 
seen an example of how to use this option / determine the file 
descriptor of an existing tun/tap interface, so I dont know how to use 
it as well. An example would be good.

[Qemu-devel] Re: Any interest in an option to use an existing tun/tap device?

[Alexander E. Patrakov]

Jesus M. Salvo Jr. wrote:
> Rob Browning wrote:
> 
>> It would be nice if qemu could be configured to use an existing
>> tun/tap device rather than require root (or sudo) access.  Would
>> others be interested in such an addition, perhaps "qemu -tun tun0" or
>> similar.
>>
>> User Mode Linux allows something similar.  See the section "TUN/TAP
>> with a preconfigured tap device" at
>> http://user-mode-linux.sourceforge.net/networking.html.
>>
>> Thanks
>>
> 
> I thought it already does, via the -tun-fd option ... though I have not 
> seen an example of how to use this option / determine the file 
> descriptor of an existing tun/tap interface, so I dont know how to use 
> it as well. An example would be good.

(not tested, but might work in bash)

qemu -other-options -tun-fd 3 3<>/dev/net/tun

-- 
Alexander E. Patrakov

[Qemu-devel] Re: Any interest in an option to use an existing tun/tap device?

[Rob Browning]

Rob Browning <rlb@defaultvalue.org> writes:

> I thought it already does, via the -tun-fd option ... though I have
> not seen an example of how to use this option / determine the file
> descriptor of an existing tun/tap interface, so I dont know how to
> use it as well. An example would be good.

Sure, though if I understand that option, it means you have to already
have the fd open (i.e. via a parent process and exec).  For persistent
tun devices, it would probably be more convenient to just be able to
specify the name.

-- 
Rob Browning
rlb @defaultvalue.org and @debian.org; previously @cs.utexas.edu
GPG starting 2002-11-03 = 14DD 432F AE39 534D B592  F9A0 25C8 D377 8C7E 73A4