EMAC LInk Status

#include <errno.h>
#include <linux/ethtool.h>
#include <linux/sockios.h>
#include <net/if.h>
#include <stdio.h>
#include <string.h>
#include <sys/ioctl.h>

int main ( int argc, char **argv )
{
  struct ifreq ifr;
  int sock = socket ( AF_INET, SOCK_DGRAM, 0 );
  struct ethtool_cmd edata;
  char ifname[32];
  int result;

  strcpy ( ifname, "eth0" );
  strncpy ( ifr.ifr_name, ifname, sizeof ( ifr.ifr_name ));
  ifr.ifr_addr.sa_family = AF_INET;

  result = ioctl ( sock, SIOCGIFFLAGS, &ifr );
  if ( result == 0 ) {
    // successfully got the flags   
    if ( ifr.ifr_flags | IFF_UP ) {
      printf ( "Ethernet interface is up\n" );
    }
    else {
      printf ( "Ethernet interface is down\n" );
    }
  }
  else {
    printf ( "%s: Error getting ethernet flags.  %s (%d)\n", 
              __FUNCTION__,
              strerror ( errno ),
              errno );
  }

  ifr.ifr_data = (char *) &edata;
  edata.cmd = ETHTOOL_GSET;
  result = ioctl ( sock, SIOCETHTOOL, &ifr );
  if ( result == 0 ) {
    switch ( edata.speed ) {
      case SPEED_10:
        printf ( "Speed is 10Mbps\n" );
        break;
      case SPEED_100:
        printf ( "Speed is 100Mbps\n" );
        break;
      case SPEED_1000:
        printf ( "Speed is 1Gbps\n" );
        break;
      case SPEED_10000:
        printf ( "Speed is 10Gbps\n" );
        break;
      default:
        printf ( "Speed (%d) is unknown\n", edata.speed );
        break;
    }
   
    if ( edata.duplex == DUPLEX_HALF ){
      printf ( "Half duplex\n" );
    }
    else {
      printf ( "Full duplex\n" );
    }
  }
  else {
    printf ( "%s: Error getting ethernet info.  %s (%d)\n", 
              __FUNCTION__,
              strerror ( errno ),
              errno );
  }
  return 0;
}