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tcp.h revision 1.6 
      1 /*	$NetBSD: tcp.h,v 1.6 1994/06/29 06:38:34 cgd Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1982, 1986, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  *
     35  *	@(#)tcp.h	8.1 (Berkeley) 6/10/93
     36  */
     37 
     38 typedef	u_long	tcp_seq;
     39 /*
     40  * TCP header.
     41  * Per RFC 793, September, 1981.
     42  */
     43 struct tcphdr {
     44 	u_short	th_sport;		/* source port */
     45 	u_short	th_dport;		/* destination port */
     46 	tcp_seq	th_seq;			/* sequence number */
     47 	tcp_seq	th_ack;			/* acknowledgement number */
     48 #if BYTE_ORDER == LITTLE_ENDIAN
     49 	u_char	th_x2:4,		/* (unused) */
     50 		th_off:4;		/* data offset */
     51 #endif
     52 #if BYTE_ORDER == BIG_ENDIAN
     53 	u_char	th_off:4,		/* data offset */
     54 		th_x2:4;		/* (unused) */
     55 #endif
     56 	u_char	th_flags;
     57 #define	TH_FIN	0x01
     58 #define	TH_SYN	0x02
     59 #define	TH_RST	0x04
     60 #define	TH_PUSH	0x08
     61 #define	TH_ACK	0x10
     62 #define	TH_URG	0x20
     63 	u_short	th_win;			/* window */
     64 	u_short	th_sum;			/* checksum */
     65 	u_short	th_urp;			/* urgent pointer */
     66 };
     67 
     68 #define	TCPOPT_EOL		0
     69 #define	TCPOPT_NOP		1
     70 #define	TCPOPT_MAXSEG		2
     71 #define	   TCPOLEN_MAXSEG		4
     72 #define	TCPOPT_WINDOW		3
     73 #define	   TCPOLEN_WINDOW		3
     74 #define	TCPOPT_SACK_PERMITTED	4		/* Experimental */
     75 #define	   TCPOLEN_SACK_PERMITTED	2
     76 #define	TCPOPT_SACK		5		/* Experimental */
     77 #define	TCPOPT_TIMESTAMP	8
     78 #define	   TCPOLEN_TIMESTAMP		10
     79 #define	   TCPOLEN_TSTAMP_APPA		(TCPOLEN_TIMESTAMP+2) /* appendix A */
     80 
     81 #define TCPOPT_TSTAMP_HDR	\
     82     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
     83 
     84 /*
     85  * Default maximum segment size for TCP.
     86  * With an IP MSS of 576, this is 536,
     87  * but 512 is probably more convenient.
     88  * This should be defined as min(512, IP_MSS - sizeof (struct tcpiphdr)).
     89  */
     90 #define	TCP_MSS		512
     91 
     92 #define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */
     93 
     94 #define	TCP_MAX_WINSHIFT	14	/* maximum window shift */
     95 
     96 /*
     97  * User-settable options (used with setsockopt).
     98  */
     99 #define	TCP_NODELAY	0x01	/* don't delay send to coalesce packets */
    100 #define	TCP_MAXSEG	0x02	/* set maximum segment size */
    101