This patch implements if_nametoindex and if_indextoname for Linux.
Both functions work by creating a temporary AF_UNIX socket and issuing
ioctl calls (SIOCGIFINDEX and SIOCGIFNAME, respectively).
The main implementation details:
- for if_nametoindex, I check that the interface name fits within
IF_NAMESIZE before issuing the ioctl
- for if_indextoname, if the kernel returns ENODEV for an unknown index,
I map it to ENXIO to comply with POSIX requirements
- added the definition of struct ifreq to support these operations.
Similar to the other net structure definitions, I'm using an anonymous
union to avoid #defining members.
Assisted by Gemini.
12c36c7abb