text: #include <sys/ioctl.h>
  #include <sys/socket.h>
  #include <linux/if.h>
  #include <linux/if_tun.h>
  #include <stddef.h>
  
  
  unsigned long ifr_size() {
    return (unsigned long) sizeof(struct ifreq);
  }
  
  
  unsigned long ifnamesiz() {
    return (unsigned long) IFNAMSIZ;
  }
  
  
  unsigned long ifname_offset() {
    return (unsigned long) offsetof(struct ifreq, ifr_name);
  }
  
  
  unsigned long ifname_member_size() {
    struct ifreq ifr;
    return (unsigned long) sizeof(ifr.ifr_name);
  }
  
  
  unsigned long ifr_flags_offset() {
    return (unsigned long) offsetof(struct ifreq, ifr_flags);
  }
  
  
  unsigned long ifr_flags_size() {
    struct ifreq ifr;
    return (unsigned long) sizeof(ifr.ifr_flags);
  }
  
  
  unsigned long iff_tap() {
    return (unsigned long) IFF_TAP;
  }
  
  
  unsigned long iff_no_pi() {
    return (unsigned long) IFF_NO_PI;
  }
  
  
  unsigned long tunsetiff() {
    return (unsigned long) TUNSETIFF;
  }
  