xref: /src/sys/netinet/ip.h

/*	$NetBSD: ip.h,v 1.39 2022/04/17 21:24:53 andvar Exp $	*/

/*
 * 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. 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
 */

#ifndef _NETINET_IP_H_
#define _NETINET_IP_H_

#include <sys/types.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>	/* for n_time */

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

/*
 * Structure of an internet header, naked of options.
 */
struct ip {
#if BYTE_ORDER == LITTLE_ENDIAN
	unsigned int ip_hl:4,		/* header length */
		     ip_v:4;		/* version */
#endif
#if BYTE_ORDER == BIG_ENDIAN
	unsigned int ip_v:4,		/* version */
		     ip_hl:4;		/* header length */
#endif
	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_RF 0x8000			/* reserved fragment flag */
#define	IP_EF 0x8000			/* evil flag, per RFC 3514 */
#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 */
};

#define	IP_MAXPACKET	65535		/* maximum packet size */
#define	IP_MINFRAGSIZE	69		/* minimum size that can be fraged */

/*
 * Definitions for IP type of service (ip_tos)
 */

/*
 * Definitions for DiffServ Codepoints as per RFC2474
 */
#define	IPTOS_DSCP_CS0		0x00
#define	IPTOS_DSCP_CS1		0x20
#define	IPTOS_DSCP_AF11		0x28
#define	IPTOS_DSCP_AF12		0x30
#define	IPTOS_DSCP_AF13		0x38
#define	IPTOS_DSCP_CS2		0x40
#define	IPTOS_DSCP_AF21		0x48
#define	IPTOS_DSCP_AF22		0x50
#define	IPTOS_DSCP_AF23		0x58
#define	IPTOS_DSCP_CS3		0x60
#define	IPTOS_DSCP_AF31		0x68
#define	IPTOS_DSCP_AF32		0x70
#define	IPTOS_DSCP_AF33		0x78
#define	IPTOS_DSCP_CS4		0x80
#define	IPTOS_DSCP_AF41		0x88
#define	IPTOS_DSCP_AF42		0x90
#define	IPTOS_DSCP_AF43		0x98
#define	IPTOS_DSCP_CS5		0xa0
#define	IPTOS_DSCP_EF		0xb8
#define	IPTOS_DSCP_CS6		0xc0
#define	IPTOS_DSCP_CS7		0xe0

/*
 * Definitions for DiffServ Class Selector Codepoints
 */
#define	IPTOS_CLASS_CS0		0x00
#define	IPTOS_CLASS_CS1		0x20
#define	IPTOS_CLASS_CS2		0x40
#define	IPTOS_CLASS_CS3		0x60
#define	IPTOS_CLASS_CS4		0x80
#define	IPTOS_CLASS_CS5		0xa0
#define	IPTOS_CLASS_CS6		0xc0
#define	IPTOS_CLASS_CS7		0xe0
#define	IPTOS_CLASS_DEFAULT	IPTOS_CLASS_CS0
#define	IPTOS_CLASS_MASK	0xe0
#define	IPTOS_CLASS(cs)		((cs) & IPTOS_CLASS_MASK)
#define	IPTOS_DSCP_MASK		0xfc
#define	IPTOS_DSCP(cp)		((cp) & IPTOS_DSCP_MASK)

/*
 * ECN (Explicit Congestion Notification) codepoints in RFC3168
 * mapped to the lower 2 bits of the TOS field.
 */
#define	IPTOS_ECN_NOTECT	0x00	/* not-ECT */
#define	IPTOS_ECN_ECT1		0x01	/* ECN-capable transport (1) */
#define	IPTOS_ECN_ECT0		0x02	/* ECN-capable transport (0) */
#define	IPTOS_ECN_CE		0x03	/* congestion experienced */
#define	IPTOS_ECN_MASK		0x03	/* ECN field mask */
#define	IPTOS_ECN(cn)		((cn) & IPTOS_ECN_MASK)
#define	IPTOS_ECN_NOT_ECT	0x00

/*
 * Definitions for IP type of service per RFC1349 (ip_tos)
 * DEPRECATED
 */
#define	IPTOS_LOWDELAY		0x10
#define	IPTOS_THROUGHPUT	0x08
#define	IPTOS_RELIABILITY	0x04
#define	IPTOS_MINCOST		0x02
/* ECN RFC3168 obsoletes RFC2481, and these will be deprecated soon. */
#define	IPTOS_CE		0x01	/* congestion experienced */
#define	IPTOS_ECT		0x02	/* ECN-capable transport */

/*
 * Definitions for IP precedence per RFC1195 (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_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_int8_t ipt_code;		/* IPOPT_TS */
	u_int8_t ipt_len;		/* size of structure (variable) */
	u_int8_t ipt_ptr;		/* index of current entry */
#if BYTE_ORDER == LITTLE_ENDIAN
	unsigned int ipt_flg:4,		/* flags, see below */
		     ipt_oflw:4;	/* overflow counter */
#endif
#if BYTE_ORDER == BIG_ENDIAN
	unsigned int ipt_oflw:4,	/* overflow counter */
		     ipt_flg:4;		/* flags, see below */
#endif
	union ipt_timestamp {
		 n_time	ipt_time[1];
		 struct	ipt_ta {
			struct in_addr ipt_addr;
			n_time 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	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 */

/*
 * This is the real IPv4 pseudo header, used for computing the TCP and UDP
 * checksums. For the Internet checksum, struct ipovly can be used instead.
 * For stronger checksums, the real thing must be used.
 */
struct ippseudo {
	struct	in_addr	ippseudo_src;	/* source internet address */
	struct	in_addr	ippseudo_dst;	/* destination internet address */
	u_int8_t	ippseudo_pad;	/* pad, must be zero */
	u_int8_t	ippseudo_p;	/* protocol */
	u_int16_t	ippseudo_len;	/* protocol length */
};

#ifdef __CTASSERT
__CTASSERT(sizeof(struct ip) == 20);
__CTASSERT(sizeof(struct ip_timestamp) == 12);
__CTASSERT(sizeof(struct ippseudo) == 12);
#endif

#endif	/* !_NETINET_IP_H_ */