ip.h

<B>Digital的Unix操作系统VAX 4.2源码</B>

/*static       char    *sccsid = "@(#)ip.h	4.3  (ULTRIX)        11/9/90"; */

/************************************************************************
 *									*
 *			Copyright (c) 1985 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *			Modification History				*
 *									*
 *	Uttam Shikarpur - 10/17/89    					*
 *		Made the value of MAXTTL, a manifest constant,    	*
 *		writeable.						*
 *	Larry Cohen  -	09/16/85					*
 * 		Add 43bsd alpha tape changes for subnet routing		*
 *									*
 *	Larry Cohen  -  01/28/87
 * 		Offsets to fields in options other than EOL and NOP.
 *		
 ************************************************************************/

/*
 * Copyright (c) 1982 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *	@(#)ip.h	6.5 (Berkeley) 6/8/85
 */
#ifdef KERNEL
#include "../h/ansi_compat.h"
#else
#include <ansi_compat.h>
#endif

/*
 * 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 {

#ifdef __vax
	u_char	ip_hl:4,		/* header length */
		ip_v:4;			/* version */
#endif /* __vax */

#ifdef __mips
#ifdef __MIPSEL
	u_char	ip_hl:4,		/* header length */
		ip_v:4;			/* version */
#endif /* __MIPSEL */
#ifdef __MIPSEB
	u_char	ip_v:4,			/* version */
		ip_hl:4;		/* header length */
#endif /* __MIPSEB */
#endif /* __mips */

	u_char	ip_tos;			/* type of service */
	short	ip_len;			/* total length */
	u_short	ip_id;			/* identification */
	short	ip_off;			/* fragment offset field */
#define	IP_DF 0x4000			/* dont fragment flag */
#define	IP_MF 0x2000			/* more fragments flag */
	u_char	ip_ttl;			/* time to live */
	u_char	ip_p;			/* protocol */
	u_short	ip_sum;			/* checksum */
	struct	in_addr ip_src,ip_dst;	/* source and dest address */
};

/*
 * 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_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 */

/*
 * 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_char	ipt_code;		/* IPOPT_TS */
	u_char	ipt_len;		/* size of structure (variable) */
	u_char	ipt_ptr;		/* index of current entry */

#ifdef __vax
	u_char	ipt_flg:4,		/* flags, see below */
		ipt_oflw:4;		/* overflow counter */
#endif /* __vax */

#ifdef __mips
#ifdef __MIPSEL
	u_char	ipt_flg:4,		/* flags, see below */
		ipt_oflw:4;		/* overflow counter */
#endif /* __MIPSEL */
#ifdef __MIPSEB
	u_char	ipt_oflw:4,		/* overflow counter */
		ipt_flg:4;		/* flags, see below */
#endif /* __MIPSEB */
#endif /* __mips */

	union ipt_timestamp {
		n_long	ipt_time[1];
		struct	ipt_ta {
			struct in_addr ipt_addr;
			n_long ipt_time;
		} ipt_ta[1];
	} ipt_timestamp;
};

/* flag bits for ipt_flg */
#define	IPOPT_TS_TSONLY		0		/* timestamps only */
#define	IPOPT_TS_TSANDADDR	1		/* timestamps and addresses */
#define	IPOPT_TS_PRESPEC	2		/* 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
#define	IPFRAGTTL	15		/* time to live for frag chains */
#define	IPTTLDEC	1		/* subtracted when forwarding */

#define	IP_MSS		576		/* default maximum segment size */
extern int maxttl;			/* MAXTTL assigned in net/ip_icmp.c */