tcp.h

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

/* @(#) $Header: /tcpdump/master/tcpdump/tcp.h,v 1.7 2000/10/03 09:17:41 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.
 *
 * @(#)tcp.h 8.1 (Berkeley) 6/10/93
 */

typedef u_int32_t tcp_seq;

/*
 * TCP header.
 * Per RFC 793, September, 1981.
 */
struct tcphdr {
       u_int16_t th_sport;           /* source port */
       u_int16_t th_dport;           /* destination port */
       tcp_seq   th_seq;             /* sequence number */
       tcp_seq   th_ack;             /* acknowledgement number */
       u_int8_t  th_offx2;           /* data offset, rsvd */
#define TH_OFF(th)	(((th)->th_offx2 & 0xf0) >> 4)
       u_int8_t  th_flags;
#define	TH_FIN	0x01
#define	TH_SYN	0x02
#define	TH_RST	0x04
#define	TH_PUSH	0x08
#define	TH_ACK	0x10
#define	TH_URG	0x20
       u_int16_t th_win;             /* window */
       u_int16_t th_sum;             /* checksum */
       u_int16_t th_urp;             /* urgent pointer */
     };

#define TCPOPT_EOL               0
#define TCPOPT_NOP               1
#define TCPOPT_MAXSEG            2
#define   TCPOLEN_MAXSEG         4
#define TCPOPT_WINDOW            3
#define   TCPOLEN_WINDOW         3
#define TCPOPT_SACK_PERMITTED    4  /* Experimental */
#define   TCPOLEN_SACK_PERMITTED 2
#define TCPOPT_SACK              5  /* Experimental */
#define TCPOPT_TIMESTAMP         8
#define   TCPOLEN_TIMESTAMP      10
#define   TCPOLEN_TSTAMP_APPA    (TCPOLEN_TIMESTAMP+2) /* appendix A */

#define TCPOPT_TSTAMP_HDR \
        (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)