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   1 /* @(#) $Header: /tcpdump/master/tcpdump/tcp.h,v 1.3 2000-09-29 05:05:48 guy Exp $ (LBL) */
   2 /*
   3  * Copyright (c) 1982, 1986, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. All advertising materials mentioning features or use of this software
  15  *    must display the following acknowledgement:
  16  *      This product includes software developed by the University of
  17  *      California, Berkeley and its contributors.
  18  * 4. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)tcp.h       8.1 (Berkeley) 6/10/93
  35  */
  36
  37 #ifndef BYTE_ORDER
  38 #define LITTLE_ENDIAN   1234    /* least-significant byte first (vax, pc) */
  39 #define BIG_ENDIAN      4321    /* most-significant byte first (IBM, net) */
  40 #define PDP_ENDIAN      3412    /* LSB first in word, MSW first in long (pdp)*/
  41
  42 #ifdef WORDS_BIGENDIAN
  43 #define BYTE_ORDER      BIG_ENDIAN
  44 #else
  45 #define BYTE_ORDER      LITTLE_ENDIAN
  46 #endif /* WORDS_BIGENDIAN */
  47 #endif /* BYTE_ORDER */
  48
  49 #if !defined(BYTE_ORDER) || \
  50     (BYTE_ORDER != BIG_ENDIAN && BYTE_ORDER != LITTLE_ENDIAN && \
  51     BYTE_ORDER != PDP_ENDIAN)
  52         /* you must determine what the correct bit order is for
  53          * your compiler - the next line is an intentional error
  54          * which will force your compiles to bomb until you fix
  55          * the above macros.
  56          */
  57   #error "Undefined or invalid BYTE_ORDER";
  58 #endif
  59
  60 typedef u_int   tcp_seq;
  61 /*
  62  * TCP header.
  63  * Per RFC 793, September, 1981.
  64  */
  65 struct tcphdr {
  66         u_short th_sport;               /* source port */
  67         u_short th_dport;               /* destination port */
  68         tcp_seq th_seq;                 /* sequence number */
  69         tcp_seq th_ack;                 /* acknowledgement number */
  70 #if BYTE_ORDER == LITTLE_ENDIAN
  71         u_int   th_x2:4,                /* (unused) */
  72                 th_off:4;               /* data offset */
  73 #endif
  74 #if BYTE_ORDER == BIG_ENDIAN
  75         u_int   th_off:4,               /* data offset */
  76                 th_x2:4;                /* (unused) */
  77 #endif
  78         u_char  th_flags;
  79 #define TH_FIN  0x01
  80 #define TH_SYN  0x02
  81 #define TH_RST  0x04
  82 #define TH_PUSH 0x08
  83 #define TH_ACK  0x10
  84 #define TH_URG  0x20
  85         u_short th_win;                 /* window */
  86         u_short th_sum;                 /* checksum */
  87         u_short th_urp;                 /* urgent pointer */
  88 };
  89
  90 #define TCPOPT_EOL              0
  91 #define TCPOPT_NOP              1
  92 #define TCPOPT_MAXSEG           2
  93 #define    TCPOLEN_MAXSEG               4
  94 #define TCPOPT_WINDOW           3
  95 #define    TCPOLEN_WINDOW               3
  96 #define TCPOPT_SACK_PERMITTED   4               /* Experimental */
  97 #define    TCPOLEN_SACK_PERMITTED       2
  98 #define TCPOPT_SACK             5               /* Experimental */
  99 #define TCPOPT_TIMESTAMP        8
 100 #define    TCPOLEN_TIMESTAMP            10
 101 #define    TCPOLEN_TSTAMP_APPA          (TCPOLEN_TIMESTAMP+2) /* appendix A */
 102
 103 #define TCPOPT_TSTAMP_HDR       \
 104     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)