tuntap.c

#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <error.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <linux/if_tun.h>
#include <net/if.h>

int main()
{
  struct ifreq ifr;
  int f, err;
  char* dev;

  memset(&ifr, 0, sizeof(ifr));
  err = 0;
  f = open("/dev/net/tun", O_RDWR);
  dev= strdup("tap0");

  ifr.ifr_flags = IFF_TAP;
  strncpy(ifr.ifr_name, dev, IFNAMSIZ);
  printf("%s\n", dev);
  if( (err = ioctl(f, TUNSETIFF,(void *) &ifr)) < 0 ){
    perror("error\n");
    close(f); 
    return err; 
  }
  strcpy(dev, ifr.ifr_name);
  printf("%s\n", dev);

  free(dev);
  return system("ifconfig tap0 up");
}