Comment # 14 on bug 1010047 from Michal Kube��ek

(In reply to Lee Duncan from comment #7)
> I am happy to fix this now, but not sure what the maximum length of a NIC
> can be these days. The code assumes 7 characters long, but in your case
> "enp0s16f0" is 9 characters long, hence the misalignment for the rest of the
> line.
> 
> In researching this, it looks like 15 or 16 bytes is the maximum, so I'll
> fix that.

The limit has been IFNNAMSIZ = 16 since ever but that includes the trailing
null byte, leaving 15 characters for the actual name.

Recent kernels (5.5 and newer - but we also have a backport in SLE15-SP2 and
openSUSE-15.2) also allow assingning zero or more alternative names (altnames)
to a network device which can be as long as ALTIFNAMSIZ = 128, again including
the trailing null byte. These are usually not shown in command output but
userspace can use them to identify a network device.