dev.* analogue for interfaces

[Robert Watson]

On Wed, 20 Feb 2008, Dag-Erling Smørgrav wrote:

> Robert Watson <rwatson at FreeBSD.org> writes:
>
>> We also support interface renaming...  Does newbus mind if you rename the 
>> devices in its tree?
>
> I'm not sure whether you're replying to my proposal or to Julian's 
> interpretation / extrapolation of it...  but I have no intention of hooking 
> interfaces into newbus.  I just want a sysctl tree for struct ifnet like we 
> have a sysctl tree for device_t, to access interface parameters which are 
> not easily accessible through ifconfig.

Hmm.  When I look at net/if.c, I don't see renaming support, so perhaps this 
was just a proposal I was thinking of and not actual code.  In either case, I 
think the question stands: in a world where interface renaming is supported, 
is your plan to also rename the if.X sysctl tree created for the interface? 
Does sysctl have a facility to do this?

I assume that somehow the details of your plan involve automatically creating 
a root node for the interface in if_attach and then exposing the node to the 
driver, possibly via a new pointer in struct ifnet?  I'm certainly fine with 
such a notion, but think we should establish, for devices with a number of 
sysctl trees (i.e., dev.em vs if.em, dev.da0 vs disk.da0, etc), a general 
philosophy for placing nodes in one or the other somewhat deterministically.

Robert N M Watson
Computer Laboratory
University of Cambridge