Determine if a network interface is wireless or wired

Question

I have a program that has two separate sections: one of them should be executed when the network interface is wireless LAN and the other one when it\'s a wired LAN connectio

Answer 1

You can call ioctl(fd, SIOCGIWNAME) that returns the wireless extension protocol version, which is only available on interfaces that are wireless.

int check_wireless(const char* ifname, char* protocol) {
  int sock = -1;
  struct iwreq pwrq;
  memset(&pwrq, 0, sizeof(pwrq));
  strncpy(pwrq.ifr_name, ifname, IFNAMSIZ);

  if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
    perror("socket");
    return 0;
  }

  if (ioctl(sock, SIOCGIWNAME, &pwrq) != -1) {
    if (protocol) strncpy(protocol, pwrq.u.name, IFNAMSIZ);
    close(sock);
    return 1;
  }

  close(sock);
  return 0;
}

For a complete example see: https://gist.github.com/edufelipe/6108057