#include <sys/ioctl.h>
#include <net/if.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include <cstdio>
using namespace std;

void getMAC( )
{
  //Interface structure to pass commands to ioctl
  struct ifreq ifr;

   
  //Structure containing the network interface name and index
  struct if_nameindex* if_name;
   
  //Convenience variable to point to the MAC address
  unsigned char* mac;

  //String buffer to store the MAC
  char actualMac[ 50 ];
   
  int sd,
      i = 0;

  sd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
  if(sd != -1)
  {

    //Retrieve the available list of network interface cards and their names and indices
    if_name = if_nameindex();

    //Parse the list
    //The ending entry in if_name is terminated by NULL
    while( if_name[i].if_name != NULL )

    {
       //Copy the interface name to the ioctl request structure
       memcpy(&ifr.ifr_name, if_name[i].if_name, IFNAMSIZ);
       
       //Pass signal to ioctl requesting the hardware address
       if (ioctl(sd, SIOCGIFHWADDR, &ifr) >= 0)
       {
          //Assign result in MAC (because "mac" is shorter than "ifr.ifr_hwaddr.sa_data" :-D )
          mac = (unsigned char*) &ifr.ifr_hwaddr.sa_data;
            
          //Store the address as a string in "actualMac"

          sprintf(actualMac,"%02X:%02X:%02X:%02X:%02X:%02X",mac[0],mac[1],mac[2],mac[3],mac[4],mac[5]);

       }
       else  //Error: Unable to retrieve the address
          printf("Unable to retrieve MAC address for %s\n", if_name[i].if_name );
         

       ++i;
    }
      
    //Free the buffers used by the if_nameindex function 
    if_freenameindex(if_name);
  }

}