#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <sys/ioctl.h>


#include <netinet/in.h>

int main(void)
{
	int 		sd;
	struct ifreq 	ifr, *ifrp;
	struct ifconf 	ifc;
	char buf[1024];
	int		n, i;
	unsigned char 	*a;
	struct sockaddr_dl *sdlp;

#ifndef max
#define max(a,b) ((a) > (b) ? (a) : (b))
#endif
#define ifreq_size(i) max(sizeof(struct ifreq),\
     sizeof((i).ifr_name)+(i).ifr_addr.sa_len)

	sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
	if (sd < 0) {
		return -1;
	}
	memset(buf, 0, sizeof(buf));
	ifc.ifc_len = sizeof(buf);
	ifc.ifc_buf = buf;
	if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
		close(sd);
		return -1;
	}
	n = ifc.ifc_len;
	for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
		ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
		strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
#ifdef SIOCGIFHWADDR
#error SIOCGIFHWADDR
#else
#ifdef SIOCGENADDR
#error SIOCGENADDR
#else
#ifdef AF_LINK
		sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
		if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
			continue;
		a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
#else
#error "No options"
#endif /* AF_LINK */
#endif /* SIOCGENADDR */
#endif /* SIOCGIFHWADDR */
		/*
		 * Skip interfaces that return either 00:00:00:00:00:00 or
		 * 02:00:00:00:00:00.
		 */
		//if ((!a[0] || a[0] == 0x02) && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
		//	continue;
        printf("%02x:%02x:%02x:%02x:%02x:%02x\n", 
                    (int)(a[0]),
                    (int)(a[1]),
                    (int)(a[2]),
                    (int)(a[3]),
                    (int)(a[4]),
                    (int)(a[5]));
	}
	close(sd);
	return 0;
}