#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
typedef unsigned short u16;
typedef unsigned int u32;
typedef unsigned char u8;
#include <linux/ethtool.h>
#include <linux/sockios.h>

int detect_mii(int skfd, char *ifname)
	{
	struct ifreq ifr;
	u16 *data, mii_val;
	unsigned phy_id;

	/* Get the vitals from the interface. */
	strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
	if (ioctl(skfd, SIOCGMIIPHY, &ifr) < 0)
		{
		fprintf(stderr, "SIOCGMIIPHY on %s failed: %s\n", ifname,
			strerror(errno));
		(void) close(skfd);
		return 2;
		}

	data = (u16 *)(&ifr.ifr_data);
	phy_id = data[0];
	data[1] = 1;

	if (ioctl(skfd, SIOCGMIIREG, &ifr) < 0)
		{
		fprintf(stderr, "SIOCGMIIREG on %s failed: %s\n", ifr.ifr_name,
			strerror(errno));
		return 2;
		}

	mii_val = data[3];

	return(((mii_val & 0x0016) == 0x0004) ? 0 : 1);
	}

int detect_ethtool(int skfd, char *ifname)
	{
	struct ifreq ifr;
	struct ethtool_value edata;
                                                                                
	memset(&ifr, 0, sizeof(ifr));
	edata.cmd = ETHTOOL_GLINK;

	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)-1);
	ifr.ifr_data = (char *) &edata;
                                                                                
	if (ioctl(skfd, SIOCETHTOOL, &ifr) == -1)
		{
		printf("ETHTOOL_GLINK failed: %s\n", strerror(errno));
		return 2;
		}
                                                                                
	return (edata.data ? 0 : 1);
	}

int main(int argc, char **argv)
	{
	int skfd = -1;
	char *ifname;
	int retval;

	if( argv[1] )
		ifname = argv[1];
	else
		ifname = "eth0";

	/* Open a socket. */
	if (( skfd = socket( AF_INET, SOCK_DGRAM, 0 ) ) < 0 )
		{
		printf("socket error\n");
		exit(-1);
		}

	retval = detect_ethtool(skfd, ifname);

	if (retval == 2)
		retval = detect_mii(skfd, ifname);

	close(skfd);

	if (retval == 2)
		printf("Could not determine status\n");

	if (retval == 1)
		printf("Link down\n");

	if (retval == 0)
		printf("Link up\n");

	return retval;
	}