/*	$FreeBSD: stable/9/sys/netipsec/ipcomp.h 139823 2005-01-07 01:45:51Z imp $	*/
/*	$KAME: ipcomp.h,v 1.8 2000/09/26 07:55:14 itojun Exp $	*/

/*-
 * Copyright (C) 1999 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * RFC2393 IP payload compression protocol (IPComp).
 */

#ifndef _NETIPSEC_IPCOMP_H_
#define _NETIPSEC_IPCOMP_H_

struct ipcomp {
	u_int8_t comp_nxt;	/* Next Header */
	u_int8_t comp_flags;	/* reserved, must be zero */
	u_int16_t comp_cpi;	/* Compression parameter index */
};

#define	IPCOMP_HLENGTH	4	/* Length of IPCOMP header */

/* well-known algorithm number (in CPI), from RFC2409 */
#define IPCOMP_OUI	1	/* vendor specific */
#define IPCOMP_DEFLATE	2	/* RFC2394 */
#define IPCOMP_LZS	3	/* RFC2395 */
#define IPCOMP_MAX	4

#define IPCOMP_CPI_NEGOTIATE_MIN	256
#endif /*_NETIPSEC_IPCOMP_H_*/
