using C code to get same info as ifconfig

Is there a way in Linux, using C code, to get the same information that “ifconfig eth0” would return? I’m interested in things like IP address, link status, and MAC address.

Here’s sample output from ifconfig:

eth0      Link encap:Ethernet  HWaddr 00:0F:20:CF:8B:42
          inet addr:217.149.127.10  Bcast:217.149.127.63  Mask:255.255.255.192
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2472694671 errors:1 dropped:0 overruns:0 frame:0
          TX packets:44641779 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1761467179 (1679.8 Mb)  TX bytes:2870928587 (2737.9 Mb)
          Interrupt:28 

Answer

Yes, ifconfig itself is written in C. 🙂 See: http://cvsweb.netbsd.org/bsdweb.cgi/src/sbin/ifconfig/ifconfig.c?rev=1.169&content-type=text/x-cvsweb-markup

Do man netdevice to see the details (on Linux). You use the ioctl() system call.