Linux TUN/TAP virtual network interfaces – Interfaces creation via C code

Here is the source code discussed in this video episode

/* The Linux Channel
 * Code for Video Episode: 0x1b0 Linux TUN/TAP interfaces creation via C code - Ep5
 * Author: Kiran Kankipati
 * Updated: 14-Apr-2019
 * tun_tap_create.c
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdbool.h>
#include <ctype.h>
#include <linux/if.h>
#include <linux/if_tun.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <fcntl.h>

/* create via CLI: (if not via this code)
# ip tuntap help
Usage: ip tuntap { add | del } [ dev PHYS_DEV ] 
          [ mode { tun | tap } ] [ user USER ] [ group GROUP ]
          [ one_queue ] [ pi ] [ vnet_hdr ]

Where: USER  := { STRING | NUMBER }
       GROUP := { STRING | NUMBER }
*/
/*
sudo ip addr add 192.168.3.1/24 dev mytuntap1
sudo ip link set dev mytuntap1 up (or) sudo ifconfig mytuntap1 up
ping 192.168.3.1
*/

#define TUN_TAP_INT "mytuntap1"

int tun_tap_create(char *name, int type)
{ //type: IFF_TUN or IFF_TAP
  struct ifreq ifr;
  int fd, ret;

  if((fd = open("/dev/net/tun", O_RDWR)) < 0) { printf("error: open()\n"); return fd; }

  memset(&ifr, 0, sizeof(ifr));

  ifr.ifr_flags = type;
  strncpy(ifr.ifr_name, name, IFNAMSIZ);

  if((ret = ioctl(fd, TUNSETIFF, (void *)&ifr)) < 0 ) {
    close(fd);
    return ret;
  }

  return fd;
}

void main()
{	int fd1, len; char buf[2000];

	fd1=tun_tap_create(TUN_TAP_INT, IFF_TAP);
	if(fd1>0) { printf("interface %s created!\n", TUN_TAP_INT); } else { printf("interface %s creation failed!\n", TUN_TAP_INT); return; }
	while(1) 
	{
     len = read(fd1, buf, sizeof(buf));

     printf("Rx %d bytes \n", len);
     len=0;
   }
   close(fd1);
}

Refer:
Linux Kernel Source – Documentation/networking/tuntap.txt – Universal TUN/TAP device driver ↗
Wiki TUN/TAP ↗