Re: CURRENT: ifconfig tap0 results in core dump

> > % ifconfig tap0
> > tap0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
> >        inet6 fe80::2bd:9ff:fe7c:100%tap0 prefixlen 64 scopeid 0x5
> > zsh: segmentation fault (core dumped)  ifconfig tap0
> >
> >
> > I remember that ifconfig didn't dump core when my laptop ran CURRENT
> > from a few months ago.
> >
> You'll probably need to build a version of ifconfig with debugging
> symbols. And then provide a backtrace of the core dump.
> 
> How soon after killing openvpn, do you use the ifconfig command.  It
> might be possible that devfs was in the process of removing tap0, when
> you used the ifconfig command.
> 
Hm.
It looks like the "close" code for if_tap clears out the addresses of
the interface with a pretty blunt-edged "bzero", rather than removing
them in any clean fashion. As a result, ifconfig gets confused over
the address families in the tags it sees on the addresses it
enumerates off the tap interface, and collapses with a corefile.

if_tap's "close" seems to be trying to do part of what's done in
if_detach, so I split out what I think are the relevant bits from
there and used it in both places.

Any networking experts care to take a look at the patch? I suspect
there's a whole mess of locking I'm not doing for a start, but I think
it might be an improvement over the current situation.

Cheers,
Peadar.