/* stolen from some Linux example on how to read the ethernet address
   Kees Cook 1997
*/
#include <stdio.h>
#include <net/if.h>
#include <netinet/in.h>

int main(int argc, char **argv) {
    int sd;
    struct ifreq ifr;
    unsigned char *a;

    if (argc != 2) {
        fprintf(stderr, "Usage: ifname\n");
        exit(2);
    }
    sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
    if (sd < 0) {
        perror("socket");
        exit(1);
    }
    strncpy(&ifr.ifr_name, argv[1], IFNAMSIZ);
    if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0) {
        perror("ioctl SIOCGIFHWADDR");
        exit(1);
    }
    a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
    printf("%02x:%02x:%02x:%02x:%02x:%02x\n", a[0],a[1],a[2],a[3],a[4],a[5]); 
    exit(0);
}