tcp.h revision 2169 
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 *	@(#)tcp.h	8.1 (Berkeley) 6/10/93
34 * $Id: tcp.h,v 1.2 1994/08/02 07:48:52 davidg Exp $
35 */
36
37#ifndef _NETINET_TCP_H_
38#define _NETINET_TCP_H_
39
40typedef	u_long	tcp_seq;
41/*
42 * TCP header.
43 * Per RFC 793, September, 1981.
44 */
45struct tcphdr {
46	u_short	th_sport;		/* source port */
47	u_short	th_dport;		/* destination port */
48	tcp_seq	th_seq;			/* sequence number */
49	tcp_seq	th_ack;			/* acknowledgement number */
50#if BYTE_ORDER == LITTLE_ENDIAN
51	u_char	th_x2:4,		/* (unused) */
52		th_off:4;		/* data offset */
53#endif
54#if BYTE_ORDER == BIG_ENDIAN
55	u_char	th_off:4,		/* data offset */
56		th_x2:4;		/* (unused) */
57#endif
58	u_char	th_flags;
59#define	TH_FIN	0x01
60#define	TH_SYN	0x02
61#define	TH_RST	0x04
62#define	TH_PUSH	0x08
63#define	TH_ACK	0x10
64#define	TH_URG	0x20
65	u_short	th_win;			/* window */
66	u_short	th_sum;			/* checksum */
67	u_short	th_urp;			/* urgent pointer */
68};
69
70#define	TCPOPT_EOL		0
71#define	TCPOPT_NOP		1
72#define	TCPOPT_MAXSEG		2
73#define    TCPOLEN_MAXSEG		4
74#define TCPOPT_WINDOW		3
75#define    TCPOLEN_WINDOW		3
76#define TCPOPT_SACK_PERMITTED	4		/* Experimental */
77#define    TCPOLEN_SACK_PERMITTED	2
78#define TCPOPT_SACK		5		/* Experimental */
79#define TCPOPT_TIMESTAMP	8
80#define    TCPOLEN_TIMESTAMP		10
81#define    TCPOLEN_TSTAMP_APPA		(TCPOLEN_TIMESTAMP+2) /* appendix A */
82
83#define TCPOPT_TSTAMP_HDR	\
84    (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
85
86/*
87 * Default maximum segment size for TCP.
88 * With an IP MSS of 576, this is 536,
89 * but 512 is probably more convenient.
90 * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
91 */
92#define	TCP_MSS	512
93
94#define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */
95
96#define TCP_MAX_WINSHIFT	14	/* maximum window shift */
97
98/*
99 * User-settable options (used with setsockopt).
100 */
101#define	TCP_NODELAY	0x01	/* don't delay send to coalesce packets */
102#define	TCP_MAXSEG	0x02	/* set maximum segment size */
103
104#endif
105