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Re: Specifying names for tap interfaces

On Wed, Jul 04, 2012 at 06:05:02PM +0100, Roger Pau Monne wrote:
> Darren Reed wrote:
> >On 30/06/2012 2:47 AM, Roger Pau Monné wrote:
> >...
> >>>>For example being able to name Xen virtual interfaces in the
> >>>>Dom0 with a user defined name, but I'm sure other users will come up with
> >>>>other uses. What would you require for this functionality?
> >>>At the very last, being able to get the driver name and instance
> >>>number in a convenient way (e.g. in ifconfig output).
> >>Ok, I will take a look at that, which I guess will require the
> >>introduction of a new ioctl and a corresponding field in ifnet.
> >>You could always find the original name in dmesg, since everytime
> >>the name changes a line is printed, but I agree it might be
> >>confusing and difficult if you perform a lot of renames.
> >
> >Start with making the information available through drvctl
> >as part of the property list for the driver and don't worry
> >about ifconfig.
> >
> >Darren
> The attached patch adds a new ioctl to perform the rename and
> propagate that rename to the associated device_t and sysctl entries.
> Please review this patch and check that the use of the spls is
> correct. I also had to change a part of the code of bpf_setif in
> bpf.c to allow the use of interfaces that doesn't end with a number.

> From 3e90ed906c3b93a92be302e76455a22940e56d6f Mon Sep 17 00:00:00 2001
> From: Roger Pau Monne <>
> Date: Mon, 25 Jun 2012 14:58:32 +0100
> Subject: [PATCH] net: add support to rename interfaces
> Add a new ioctl "SIOCSIFNAME" to rename network interfaces and add
> support for it in ifconfig.
> The added ioctl changes the field if_xname and if_dl in the ifnet
> structure, and propagates those changes to the associated sysctl
> entries and device_t (if present), so drvctl works with the new name.

if I did read it properly, there's no way to know the driver and unit number
once the name has been changed ?

Also, there is a change to bpf that looks unrelated. As it changes the
semantic, this should at last be documented.

Manuel Bouyer <>
     NetBSD: 26 ans d'experience feront toujours la difference

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