lib/tun.h

/* 
 * TUN interface functions.
 * Copyright (C) 2002, 2003 Mondru AB.
 * 
 * The contents of this file may be used under the terms of the GNU
 * General Public License Version 2, provided that the above copyright
 * notice and this permission notice is included in all copies or
 * substantial portions of the software.
 * 
 */

#ifndef _TUN_H
#define _TUN_H

#define PACKET_MAX      8196	/* Maximum packet size we receive */
#define TUN_SCRIPTSIZE   256
#define TUN_ADDRSIZE     128
#define TUN_NLBUFSIZE   1024

struct tun_packet_t {
	unsigned int ver:4;
	unsigned int ihl:4;
	unsigned int dscp:6;
	unsigned int ecn:2;
	unsigned int length:16;
	unsigned int id:16;
	unsigned int flags:3;
	unsigned int fragment:13;
	unsigned int ttl:8;
	unsigned int protocol:8;
	unsigned int check:16;
	unsigned int src:32;
	unsigned int dst:32;
};

/* ***********************************************************
 * Information storage for each tun instance
 *************************************************************/

struct tun_t {
	int fd;			/* File descriptor to tun interface */
	struct in_addr addr;
	struct in_addr dstaddr;
	struct in_addr netmask;
	int addrs;		/* Number of allocated IP addresses */
	int routes;		/* One if we allocated an automatic route */
	char devname[IFNAMSIZ];	/* Name of the tun device */
	int (*cb_ind) (struct tun_t * tun, void *pack, unsigned len);
};

extern int tun_new(struct tun_t **tun);
extern int tun_free(struct tun_t *tun);
extern int tun_decaps(struct tun_t *this);
extern int tun_encaps(struct tun_t *tun, void *pack, unsigned len);

extern int tun_addaddr(struct tun_t *this, struct in_addr *addr,
		       struct in_addr *dstaddr, struct in_addr *netmask);

extern int tun_setaddr(struct tun_t *this, struct in_addr *our_adr,
		       struct in_addr *his_adr, struct in_addr *net_mask);

int tun_addroute(struct tun_t *this, struct in_addr *dst,
		 struct in_addr *gateway, struct in_addr *mask);

extern int tun_set_cb_ind(struct tun_t *this,
			  int (*cb_ind) (struct tun_t * tun, void *pack,
					 unsigned len));

extern int tun_runscript(struct tun_t *tun, char *script);

#endif /* !_TUN_H */