xref: /netbsd-src/sys/netinet/tcp.h (revision cda4f8f6ee55684e8d311b86c99ea59191e6b74f)
1 /*
2  * Copyright (c) 1982, 1986 Regents of the University of California.
3  * 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	7.7 (Berkeley) 6/28/90
34  *	$Id: tcp.h,v 1.3 1993/05/20 03:50:31 cgd Exp $
35  */
36 
37 #ifndef _NETINET_TCP_H_
38 #define _NETINET_TCP_H_
39 
40 typedef	u_long	tcp_seq;
41 /*
42  * TCP header.
43  * Per RFC 793, September, 1981.
44  */
45 struct 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 
74 /*
75  * Default maximum segment size for TCP.
76  * With an IP MSS of 576, this is 536,
77  * but 512 is probably more convenient.
78  * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
79  */
80 #define	TCP_MSS	512
81 
82 #define	TCP_MAXWIN	65535		/* largest value for window */
83 
84 /*
85  * User-settable options (used with setsockopt).
86  */
87 #define	TCP_NODELAY	0x01	/* don't delay send to coalesce packets */
88 #define	TCP_MAXSEG	0x02	/* set maximum segment size */
89 
90 #endif /* !_NETINET_TCP_H_ */
91