File /code/usr/include/linux/if_tun.h

#ifndef __IF_TUN_H
#define __IF_TUN_H

/* Uncomment to enable debugging */
/* #define TUN_DEBUG 1 */

#ifdef __KERNEL__

#ifdef TUN_DEBUG
#define DBG  if(tun->debug)printk
#define DBG1 if(debug==2)printk
#else
#define DBG( a... )
#define DBG1( a... )
#endif

struct tun_struct {
	char 			*name;
	unsigned long 		flags;
	int			attached;
	uid_t			owner;

	wait_queue_head_t	read_wait;
	struct sk_buff_head	readq;

	struct net_device	dev;
	struct net_device_stats	stats;

	struct fasync_struct    *fasync;

#ifdef TUN_DEBUG	
	int debug;
#endif  
};

#ifndef MIN
#define MIN(a,b) ( (a)<(b) ? (a):(b) ) 
#endif

#endif /* __KERNEL__ */

/* Read queue size */
#define TUN_READQ_SIZE	10

/* TUN device flags */
#define TUN_TUN_DEV 	0x0001	
#define TUN_TAP_DEV	0x0002
#define TUN_TYPE_MASK   0x000f

#define TUN_FASYNC	0x0010
#define TUN_NOCHECKSUM	0x0020
#define TUN_NO_PI	0x0040
#define TUN_ONE_QUEUE	0x0080
#define TUN_PERSIST 	0x0100	

/* Ioctl defines */
#define TUNSETNOCSUM  _IOW('T', 200, int) 
#define TUNSETDEBUG   _IOW('T', 201, int) 
#define TUNSETIFF     _IOW('T', 202, int) 
#define TUNSETPERSIST _IOW('T', 203, int) 
#define TUNSETOWNER   _IOW('T', 204, int)

/* TUNSETIFF ifr flags */
#define IFF_TUN		0x0001
#define IFF_TAP		0x0002
#define IFF_NO_PI	0x1000
#define IFF_ONE_QUEUE	0x2000

struct tun_pi {
	unsigned short flags;
	unsigned short proto;
};
#define TUN_PKT_STRIP	0x0001

#endif /* __IF_TUN_H */