tcp.h revision 50477 
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 * $FreeBSD: head/sys/netinet/tcp.h 50477 1999-08-28 01:08:13Z peter $
35 */
36
37#ifndef _NETINET_TCP_H_
38#define _NETINET_TCP_H_
39
40typedef	u_int32_t tcp_seq;
41typedef u_int32_t tcp_cc;		/* connection count per rfc1644 */
42
43/*
44 * TCP header.
45 * Per RFC 793, September, 1981.
46 */
47struct tcphdr {
48	u_short	th_sport;		/* source port */
49	u_short	th_dport;		/* destination port */
50	tcp_seq	th_seq;			/* sequence number */
51	tcp_seq	th_ack;			/* acknowledgement number */
52#if BYTE_ORDER == LITTLE_ENDIAN
53	u_int	th_x2:4,		/* (unused) */
54		th_off:4;		/* data offset */
55#endif
56#if BYTE_ORDER == BIG_ENDIAN
57	u_int	th_off:4,		/* data offset */
58		th_x2:4;		/* (unused) */
59#endif
60	u_char	th_flags;
61#define	TH_FIN	0x01
62#define	TH_SYN	0x02
63#define	TH_RST	0x04
64#define	TH_PUSH	0x08
65#define	TH_ACK	0x10
66#define	TH_URG	0x20
67#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG)
68
69	u_short	th_win;			/* window */
70	u_short	th_sum;			/* checksum */
71	u_short	th_urp;			/* urgent pointer */
72};
73
74#define	TCPOPT_EOL		0
75#define	TCPOPT_NOP		1
76#define	TCPOPT_MAXSEG		2
77#define    TCPOLEN_MAXSEG		4
78#define TCPOPT_WINDOW		3
79#define    TCPOLEN_WINDOW		3
80#define TCPOPT_SACK_PERMITTED	4		/* Experimental */
81#define    TCPOLEN_SACK_PERMITTED	2
82#define TCPOPT_SACK		5		/* Experimental */
83#define TCPOPT_TIMESTAMP	8
84#define    TCPOLEN_TIMESTAMP		10
85#define    TCPOLEN_TSTAMP_APPA		(TCPOLEN_TIMESTAMP+2) /* appendix A */
86#define    TCPOPT_TSTAMP_HDR		\
87    (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
88
89#define	TCPOPT_CC		11		/* CC options: RFC-1644 */
90#define TCPOPT_CCNEW		12
91#define TCPOPT_CCECHO		13
92#define	   TCPOLEN_CC			6
93#define	   TCPOLEN_CC_APPA		(TCPOLEN_CC+2)
94#define	   TCPOPT_CC_HDR(ccopt)		\
95    (TCPOPT_NOP<<24|TCPOPT_NOP<<16|(ccopt)<<8|TCPOLEN_CC)
96
97/*
98 * Default maximum segment size for TCP.
99 * With an IP MSS of 576, this is 536,
100 * but 512 is probably more convenient.
101 * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
102 */
103#define	TCP_MSS	512
104
105#define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */
106#define	TTCP_CLIENT_SND_WND	4096	/* dflt send window for T/TCP client */
107
108#define TCP_MAX_WINSHIFT	14	/* maximum window shift */
109
110#define TCP_MAXHLEN	(0xf<<2)	/* max length of header in bytes */
111#define TCP_MAXOLEN	(TCP_MAXHLEN - sizeof(struct tcphdr))
112					/* max space left for options */
113
114/*
115 * User-settable options (used with setsockopt).
116 */
117#define	TCP_NODELAY	0x01	/* don't delay send to coalesce packets */
118#define	TCP_MAXSEG	0x02	/* set maximum segment size */
119#define TCP_NOPUSH	0x04	/* don't push last block of write */
120#define TCP_NOOPT	0x08	/* don't use TCP options */
121
122#endif
123