/* @(#) $Header: /tcpdump/master/tcpdump/ip.h,v 1.12 2007-09-14 01:29:28 guy Exp $ (LBL) */
/*
 * Copyright (c) 1982, 1986, 1993
 *	The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 *	@(#)ip.h	8.2 (Berkeley) 6/1/94
 */

/*
 * Definitions for internet protocol version 4.
 * Per RFC 791, September 1981.
 */
#define	IPVERSION	4

/*
 * Structure of an internet header, naked of options.
 *
 * We declare ip_len and ip_off to be short, rather than u_short
 * pragmatically since otherwise unsigned comparisons can result
 * against negative integers quite easily, and fail in subtle ways.
 */
struct ip {
	u_int8_t	ip_vhl;		/* header length, version */
#define IP_V(ip)	(((ip)->ip_vhl & 0xf0) >> 4)
#define IP_HL(ip)	((ip)->ip_vhl & 0x0f)
	u_int8_t	ip_tos;		/* type of service */
	u_int16_t	ip_len;		/* total length */
	u_int16_t	ip_id;		/* identification */
	u_int16_t	ip_off;		/* fragment offset field */
#define	IP_DF 0x4000			/* dont fragment flag */
#define	IP_MF 0x2000			/* more fragments flag */
#define	IP_OFFMASK 0x1fff		/* mask for fragmenting bits */
	u_int8_t	ip_ttl;		/* time to live */
	u_int8_t	ip_p;		/* protocol */
	u_int16_t	ip_sum;		/* checksum */
	struct	in_addr ip_src,ip_dst;	/* source and dest address */
} UNALIGNED;

#define	IP_MAXPACKET	65535		/* maximum packet size */

/*
 * Definitions for IP type of service (ip_tos)
 */
#define	IPTOS_LOWDELAY		0x10
#define	IPTOS_THROUGHPUT	0x08
#define	IPTOS_RELIABILITY	0x04

/*
 * Definitions for IP precedence (also in ip_tos) (hopefully unused)
 */
#define	IPTOS_PREC_NETCONTROL		0xe0
#define	IPTOS_PREC_INTERNETCONTROL	0xc0
#define	IPTOS_PREC_CRITIC_ECP		0xa0
#define	IPTOS_PREC_FLASHOVERRIDE	0x80
#define	IPTOS_PREC_FLASH		0x60
#define	IPTOS_PREC_IMMEDIATE		0x40
#define	IPTOS_PREC_PRIORITY		0x20
#define	IPTOS_PREC_ROUTINE		0x00

/*
 * Definitions for options.
 */
#define	IPOPT_COPIED(o)		((o)&0x80)
#define	IPOPT_CLASS(o)		((o)&0x60)
#define	IPOPT_NUMBER(o)		((o)&0x1f)

#define	IPOPT_CONTROL		0x00
#define	IPOPT_RESERVED1		0x20
#define	IPOPT_DEBMEAS		0x40
#define	IPOPT_RESERVED2		0x60

#define	IPOPT_EOL		0		/* end of option list */
#define	IPOPT_NOP		1		/* no operation */

#define	IPOPT_RR		7		/* record packet route */
#define	IPOPT_TS		68		/* timestamp */
#define	IPOPT_RFC1393           82              /* traceroute RFC 1393 */
#define	IPOPT_SECURITY		130		/* provide s,c,h,tcc */
#define	IPOPT_LSRR		131		/* loose source route */
#define	IPOPT_SATID		136		/* satnet id */
#define	IPOPT_SSRR		137		/* strict source route */
#define IPOPT_RA                148             /* router-alert, rfc2113 */

/*
 * Offsets to fields in options other than EOL and NOP.
 */
#define	IPOPT_OPTVAL		0		/* option ID */
#define	IPOPT_OLEN		1		/* option length */
#define IPOPT_OFFSET		2		/* offset within option */
#define	IPOPT_MINOFF		4		/* min value of above */

/*
 * Time stamp option structure.
 */
struct	ip_timestamp {
	u_int8_t	ipt_code;	/* IPOPT_TS */
	u_int8_t	ipt_len;	/* size of structure (variable) */
	u_int8_t	ipt_ptr;	/* index of current entry */
	u_int8_t	ipt_oflwflg;	/* flags, overflow counter */
#define IPTS_OFLW(ip)	(((ipt)->ipt_oflwflg & 0xf0) >> 4)
#define IPTS_FLG(ip)	((ipt)->ipt_oflwflg & 0x0f)
	union ipt_timestamp {
		u_int32_t ipt_time[1];
		struct	ipt_ta {
			struct in_addr ipt_addr;
			u_int32_t ipt_time;
		} ipt_ta[1];
	} ipt_timestamp;
} UNALIGNED;

/* flag bits for ipt_flg */
#define	IPOPT_TS_TSONLY		0		/* timestamps only */
#define	IPOPT_TS_TSANDADDR	1		/* timestamps and addresses */
#define	IPOPT_TS_PRESPEC	3		/* specified modules only */

/* bits for security (not byte swapped) */
#define	IPOPT_SECUR_UNCLASS	0x0000
#define	IPOPT_SECUR_CONFID	0xf135
#define	IPOPT_SECUR_EFTO	0x789a
#define	IPOPT_SECUR_MMMM	0xbc4d
#define	IPOPT_SECUR_RESTR	0xaf13
#define	IPOPT_SECUR_SECRET	0xd788
#define	IPOPT_SECUR_TOPSECRET	0x6bc5

/*
 * Internet implementation parameters.
 */
#define	MAXTTL		255		/* maximum time to live (seconds) */
#define	IPDEFTTL	64		/* default ttl, from RFC 1340 */
#define	IPFRAGTTL	60		/* time to live for frags, slowhz */
#define	IPTTLDEC	1		/* subtracted when forwarding */

#define	IP_MSS		576		/* default maximum segment size */

/* in print-ip.c */
extern int nextproto4_cksum(const struct ip *, const u_int8_t *, u_int, u_int);