ioctl(sock, SIOCGIFHWADDR, &ifr) fails with 1.7

[Corinna Vinschen]

On Jun 15 13:42, Corinna Vinschen wrote:
> On Jun 15 11:22, Fr?d?ric Bron wrote:
> > > To fix your application, call either
> > >
> > > Â struct ifconf ifc;
> > > Â ifc.ifc_len = sizeof (struct ifreq) * 32;
> > > Â ifc.ifc_buf = malloc (ifc.ifc_len);
> > > Â if (ioctl (fd, SIOCGIFCONF, &ifc))
> > > Â  Â /* Resize ifc_buf and retry */
> > > Â else
> > > Â  Â {
> > > Â  Â  Â struct ifreq *ifr = ifc.ifc_req;
> > > Â  Â  Â struct ifreq ifr2;
> > > Â  Â  Â for (int i = 0; i < ifc.ifc_len; i += sizeof (struct ifreq), ++ifr)
> > > Â  Â  Â  Â if (!ioctl (fd, SIOCGIFADDR, &ifr2))
> > > Â  Â  Â  Â  Â /* Print result for that interface */
> > > Â  Â }
> > 
> > Thanks, this works half! No need of ifr2, ifr is enough.
> > I saw the name change: 1.5 gives eth0, eth1, eth2, lo and 1.7 gives
> > {821C54BE-...}...
> > 
> > However, with that code, I get all network adapters with cygwin 1.5
> > but only active adpaters with 1.7 (with IP adress != 0).
> > For example if I unplug the ethernet wire, the ip of eth0 becomes
> > 0.0.0.0 with 1.5 and I don't see it anymore with 1.7.
> > 
> > How can I get all interfaces with 1.7?
> 
> I just debugged this and the answer is, right now you can't.  I'm
> going to fix that at one point, but I have other stuff to do first.

I applied a patch to Cygwin which also reports the IPv4 addresses of
disconnected interfaces, fetching the info from the registry.  It's
a pity that Windows doesn't correctly report these addresses in the
official API.

This won't work for IPv6 and IPv6-only interfaces.  I didn't find a
generic way to list IPv6 addresses except for using the official API.
Since Windows Vista the IPv6 address information isn't stored in the
registry at all, at least not in a publically available, easy to read
place.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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