Re: limit of network interface name length?

From: Paul Procacci <pprocacci_at_gmail.com>
Date: Fri, 20 Oct 2023 20:56:04 UTC
On Fri, Oct 20, 2023 at 4:31 PM Ede Wolf <listac@nebelschwaden.de> wrote:

> Hello,
>
> I am trying to rename a couple of interfaces, and it works for some, for
> others not.
>
> Trying to find what I may be doing wrong, a patter that seems to emerge,
> is, that if names longer than 14Bytes are not supported. Maybe the "
> make up for the missing bytes up to 16.
>
> F.e.:
>
> ifconfig_epair6a_name="jail_template_local"
>
> does not work. The interface names remaines epair6a.
> Is that documented anywhere?
>
> Or can anyone confirm this limit on solid grounds? Just to make sure I
> have not done anything other wrong.
>
> Thanks
>
> Ede
>
>
It's defined as 16 bytes.

"/*
 * Length of interface external name, including terminating '\0'.
 * Note: this is the same size as a generic device's external name.
 */
#define         IF_NAMESIZE     16
#if __BSD_VISIBLE
#define         IFNAMSIZ        IF_NAMESIZE"

~Paul

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