Re: Bug handling devices with weird names

[Stephen Hemminger <shemminger@vyatta.com>]

On Thu, 8 Jul 2010 19:08:07 +0200
Martín Ferrari <martin.ferrari@gmail.com> wrote:

> According to dev_valid_name (net/core/dev.c), a valid device name is
> one that doesn't include spaces, slashes, and is not "." or "..". But
> if I create a device called "foo:", some operations fail:
> 
> # ip link add name foo: type dummy
> # ip link list foo:
> 155: foo:: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN ioctl(SIOCGIFXQLEN)
> failed: No such device
> 
>     link/ether 92:7f:4d:0d:8f:57 brd ff:ff:ff:ff:ff:ff
> 
> Strace reveals that the problem occurs when executing an ioctl:
> 
> ioctl(4, SIOCGIFTXQLEN, {ifr_name="foo:", ???}) = -1 ENODEV (No such device)
> 
> ifconfig gets completely lost, of course:
> 
> $ /sbin/ifconfig foo:
> foo:: error fetching interface information: Device not found
> 
> ioctl(5, SIOCGIFFLAGS, {ifr_name="foo:", ???}) = -1 ENODEV (No such device)
> 
> 
> So, is this fixable or iproute should stop using the ioctl interface?
> (dunno if netlink provides everything already)

Colons are used for the old IP aliasing. IP aliasing was an older way of handling
multiple addresses per interface, and is not necessary anymore. The syntax is
retained for legacy compatibility.