tcp.h revision 70854 
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 70854 2001-01-09 18:26:17Z rwatson $
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#define tcp6_seq	tcp_seq	/* for KAME src sync over BSD*'s */
44#define tcp6hdr		tcphdr	/* for KAME src sync over BSD*'s */
45
46/*
47 * TCP header.
48 * Per RFC 793, September, 1981.
49 */
50struct tcphdr {
51	u_short	th_sport;		/* source port */
52	u_short	th_dport;		/* destination port */
53	tcp_seq	th_seq;			/* sequence number */
54	tcp_seq	th_ack;			/* acknowledgement number */
55#if BYTE_ORDER == LITTLE_ENDIAN
56	u_int	th_x2:4,		/* (unused) */
57		th_off:4;		/* data offset */
58#endif
59#if BYTE_ORDER == BIG_ENDIAN
60	u_int	th_off:4,		/* data offset */
61		th_x2:4;		/* (unused) */
62#endif
63	u_char	th_flags;
64#define	TH_FIN	0x01
65#define	TH_SYN	0x02
66#define	TH_RST	0x04
67#define	TH_PUSH	0x08
68#define	TH_ACK	0x10
69#define	TH_URG	0x20
70#define	TH_ECE	0x40
71#define	TH_CWR	0x80
72#define	TH_FLAGS	(TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
73
74	u_short	th_win;			/* window */
75	u_short	th_sum;			/* checksum */
76	u_short	th_urp;			/* urgent pointer */
77};
78
79#define	TCPOPT_EOL		0
80#define	TCPOPT_NOP		1
81#define	TCPOPT_MAXSEG		2
82#define    TCPOLEN_MAXSEG		4
83#define TCPOPT_WINDOW		3
84#define    TCPOLEN_WINDOW		3
85#define TCPOPT_SACK_PERMITTED	4		/* Experimental */
86#define    TCPOLEN_SACK_PERMITTED	2
87#define TCPOPT_SACK		5		/* Experimental */
88#define TCPOPT_TIMESTAMP	8
89#define    TCPOLEN_TIMESTAMP		10
90#define    TCPOLEN_TSTAMP_APPA		(TCPOLEN_TIMESTAMP+2) /* appendix A */
91#define    TCPOPT_TSTAMP_HDR		\
92    (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
93
94#define	TCPOPT_CC		11		/* CC options: RFC-1644 */
95#define TCPOPT_CCNEW		12
96#define TCPOPT_CCECHO		13
97#define	   TCPOLEN_CC			6
98#define	   TCPOLEN_CC_APPA		(TCPOLEN_CC+2)
99#define	   TCPOPT_CC_HDR(ccopt)		\
100    (TCPOPT_NOP<<24|TCPOPT_NOP<<16|(ccopt)<<8|TCPOLEN_CC)
101
102/*
103 * Default maximum segment size for TCP.
104 * With an IP MSS of 576, this is 536,
105 * but 512 is probably more convenient.
106 * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
107 */
108#define	TCP_MSS	512
109
110/*
111 * Default maximum segment size for TCP6.
112 * With an IP6 MSS of 1280, this is 1220,
113 * but 1024 is probably more convenient. (xxx kazu in doubt)
114 * This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr))
115 */
116#define	TCP6_MSS	1024
117
118#define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */
119#define	TTCP_CLIENT_SND_WND	4096	/* dflt send window for T/TCP client */
120
121#define TCP_MAX_WINSHIFT	14	/* maximum window shift */
122
123#define TCP_MAXBURST		4 	/* maximum segments in a burst */
124
125#define TCP_MAXHLEN	(0xf<<2)	/* max length of header in bytes */
126#define TCP_MAXOLEN	(TCP_MAXHLEN - sizeof(struct tcphdr))
127					/* max space left for options */
128
129/*
130 * User-settable options (used with setsockopt).
131 */
132#define	TCP_NODELAY	0x01	/* don't delay send to coalesce packets */
133#define	TCP_MAXSEG	0x02	/* set maximum segment size */
134#define TCP_NOPUSH	0x04	/* don't push last block of write */
135#define TCP_NOOPT	0x08	/* don't use TCP options */
136
137#endif
138