.. the original reason was apparently that _ifconfig_ blew up
when it saw protocols that it didn't understand on network
interfaces. Possibly when there was no IP protocol on an
This happened on DECNET, and apparently on others too.
Thus the SIOCGIFCONF ioctl is not returning much else
than interfaces with IP addresses on them, and to get
_all_ interfaces, one must read thru /proc/net/dev file.
Some reason like that is possibly behind the reason why
SIOCGIFCONF does not find anything but PF_INET sockets
even when it is run on PF_AX25 type socket..
The "fun" part is that ifconfig does look for all devices
in /proc/net/dev. Perhaps we should just make all devices
findable with SIOCGIFCONF regardless of what protocols
they may support ? And if the ifconfig blows up, the
bug is in ifconfig tool, not kernel.
Alternatively one could iterate all network devices of
protocol family X being enabled when ioctl() is called
on socket with PF_x (like PF_AX25.)
Can anyone recall any real reason why this would not be