Get MAC Address

get_mac_addr.c

int get_mac_addr(char *mac_addr)
{
  int sockfd;
  struct ifreq ifr;
  
  if ((sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP)) >= 0) {
    strncpy(ifr.ifr_name, "eth0", IFNAMESIZE);
    ifr.ifr_addr.sa_family = AF_INET;
    if (ioctl(sockfd, SIOGIFHWADDR, (char*) &ifr) == 0) {
      sprintf(mac_addr, "%02X:%02X:%02X:%02X:%02X:%02X", 
              (unsigned char) ifr.ifr_ifru.ifru_hwaddr.sa_data[0], (unsigned char) ifr.ifr_ifru.ifru_hwaddr.sa_data[1],
              (unsigned char) ifr.ifr_ifru.ifru_hwaddr.sa_data[2], (unsigned char) ifr.ifr_ifru.ifru_hwaddr.sa_data[3],
              (unsigned char) ifr.ifr_ifru.ifru_hwaddr.sa_data[4], (unsigned char) ifr.ifr_ifru.ifru_hwaddr.sa_data[5]);
      return 0;  
    }
  }
  /* error */
  return -1;
}