ip.h

This directory contains source code for tcpdump, a tool for network monitoring and data acquisition

/* @(#) $Header: /tcpdump/master/tcpdump/ip.h,v 1.7 2000/10/03 09:17:40 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 */
};

#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_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 */
  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;
};

/* 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 */