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tcp.h revision 1.5 
      1 /*
      2  * Copyright (c) 1982, 1986, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  *
     33  *	from: @(#)tcp.h	8.1 (Berkeley) 6/10/93
     34  *	$Id: tcp.h,v 1.5 1994/05/13 06:06:32 mycroft Exp $
     35  */
     36 
     37 typedef	u_long	tcp_seq;
     38 /*
     39  * TCP header.
     40  * Per RFC 793, September, 1981.
     41  */
     42 struct tcphdr {
     43 	u_short	th_sport;		/* source port */
     44 	u_short	th_dport;		/* destination port */
     45 	tcp_seq	th_seq;			/* sequence number */
     46 	tcp_seq	th_ack;			/* acknowledgement number */
     47 #if BYTE_ORDER == LITTLE_ENDIAN
     48 	u_char	th_x2:4,		/* (unused) */
     49 		th_off:4;		/* data offset */
     50 #endif
     51 #if BYTE_ORDER == BIG_ENDIAN
     52 	u_char	th_off:4,		/* data offset */
     53 		th_x2:4;		/* (unused) */
     54 #endif
     55 	u_char	th_flags;
     56 #define	TH_FIN	0x01
     57 #define	TH_SYN	0x02
     58 #define	TH_RST	0x04
     59 #define	TH_PUSH	0x08
     60 #define	TH_ACK	0x10
     61 #define	TH_URG	0x20
     62 	u_short	th_win;			/* window */
     63 	u_short	th_sum;			/* checksum */
     64 	u_short	th_urp;			/* urgent pointer */
     65 };
     66 
     67 #define	TCPOPT_EOL		0
     68 #define	TCPOPT_NOP		1
     69 #define	TCPOPT_MAXSEG		2
     70 #define	   TCPOLEN_MAXSEG		4
     71 #define	TCPOPT_WINDOW		3
     72 #define	   TCPOLEN_WINDOW		3
     73 #define	TCPOPT_SACK_PERMITTED	4		/* Experimental */
     74 #define	   TCPOLEN_SACK_PERMITTED	2
     75 #define	TCPOPT_SACK		5		/* Experimental */
     76 #define	TCPOPT_TIMESTAMP	8
     77 #define	   TCPOLEN_TIMESTAMP		10
     78 #define	   TCPOLEN_TSTAMP_APPA		(TCPOLEN_TIMESTAMP+2) /* appendix A */
     79 
     80 #define TCPOPT_TSTAMP_HDR	\
     81     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
     82 
     83 /*
     84  * Default maximum segment size for TCP.
     85  * With an IP MSS of 576, this is 536,
     86  * but 512 is probably more convenient.
     87  * This should be defined as min(512, IP_MSS - sizeof (struct tcpiphdr)).
     88  */
     89 #define	TCP_MSS		512
     90 
     91 #define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */
     92 
     93 #define	TCP_MAX_WINSHIFT	14	/* maximum window shift */
     94 
     95 /*
     96  * User-settable options (used with setsockopt).
     97  */
     98 #define	TCP_NODELAY	0x01	/* don't delay send to coalesce packets */
     99 #define	TCP_MAXSEG	0x02	/* set maximum segment size */
    100