[uml-user] Re: Preconfigured TUN/TAP - was: VLAN type bridging between virtual interfaces

[David C. <da...@da...>]

Kendell Welch wrote:
> It seems that I'm unable to configure a TUN/TAP eth device for a UML to a
> preconfigured TAP device as the online documentation suggests.  Basically,
> TUN/TAP works fine if I define an IP address, but I can't assign a UML to
> a particular host TAP device under any circumstances...it always creates a
> new host device (as it would with uml_net.)

What you need to do is use 'tunctl <uid>' to create a tap device - <uid> 
is the uid of the user which runs UML. It will return a tap device, such 
as tap0, which is the one you need to use in all your commands. You can 
then run 'ifconfig tap0', or whatever tap device was created, then you 
can do;

./linux eth0=tuntap,tap0

You can then config the eth0 on the UML as needed. I'm unsure of the 
exact permissions of /dev/net/tun required for UML to use the tap 
device, so you may want to chmod it to 666 and then work out what 
exactly it needs - I personally created a 'tap' group and chowned 
/dev/net/tun to root.tap, then added my 'uml' user to the 'tap' group.

> I'm using the binary download of UML kernel 2.4.18.  The documentation
> (http://user-mode-linux.sourceforge.net/networking.html) suggests that
> 2.4.17-11 is able to provide this functionality.  Unfortunately, the page
> that allows any kind of 2.4.17 download is missing.  Suggestions?

I'd just build 2.4.18-40um - I can't remember when tunctl came into 
effect. Why can't you download the 2.4.18 binary?

David

-- 
David Coulson                                  http://davidcoulson.net/
d...@vi...                       http://journal.davidcoulson.net/