IFNAMSIZ/IF_NAMESIZE change proposal

Mon Sep 16 05:24:07 UTC 2013

On 9/15/13 12:21 AM, Warner Losh wrote:
> On Sep 14, 2013, at 2:44 AM, Anuranjan Shukla wrote:
>> At Juniper Networks, interface name size was needed to be longer than what FreeBSD has. We're trying to reduce our local changes to FreeBSD to allow us an easier time upgrading to newer FreeBSD releases, and support the modularization of the network stack we'd proposed earlier. I'm sending this  out to propose changing IFNAMSIZ from 16 to 60 (this is the size we use) in FreeBSD. We don't see any downside (other than increasing the ifreq structure size for one) to doing this, as allowing longer interface names can be handy for vendors. I'd like to hear if there's a strong objection to this. If not, we'd like to get this into to the FreeBSD codebase. Any thoughts/objections highly appreciated.

Divert already has a problem with 16, since it tries (or fails if > 8 
) to pack the interface name into the 'unused'
bytes of a sockaddr.
60 just makes things worse, but since it already fails at 16 I can't 
really object.
but it would be nice if we could think of a better mechanism for 
divert reinjection.

> 56 or 64 would be better for alignment, wouldn't it?
>
> Warner
>
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