On 19 Nov 2023, at 8:34, Mina Galić wrote:
>>> FreeBSD currently does not preserve the old ( original ) name of
>>> interfaces if it is renamed ( either physical or cloned ones ).
>>> While there's an attempt https://reviews.freebsd.org/D28247
>>> to get the device name (physical
>>> ones) but it is not perfect and not completed.
>>>
>>> So may I ask why you need to know if a network interface was renamed ?
>>
>>
>> Just last week I found this quite a pain as well; once an interface has
>> been renamed, if it's not a pseudo-interface with an obvious group
>> there's no clear way, AFAICT, to determine which driver created it
>
> I think the main reason that we need to know if and from what an interface
> has been renamed is if we need to know what driver we're working with.
>
> But given that a rename doesn't change — or even just *alias*
> the sysctl dev hierarchy, where a %driver is recorded, we can't
> track it back.
>
> (but again, that's just for physical devices, then again virtual devices
> record what type of device they are in their group which
> is essentially the same thing)
>
> As soon as we have more than one interface with different drivers
> it's impossible to parse out what we're dealing with without
> parsing rc.conf, logs, or worse things I can't think of right now.
The kernel has a driver name for each interface, which looks like it
doesn't change currently in most cases. There is a kernel accessor
function, but I don't think it is exported to user space now. It could
be, though. Would this be sufficient for your purposes? There is also
a unit number, which could also be exported.
Mike
