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  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	@(#)tcp.h	8.1 (Berkeley) 6/10/93
30  */
31 
32 #ifndef _NETINET_TCP_H
33 
34 #define _NETINET_TCP_H	1
35 #include <sys/cdefs.h>
36 
37 
38 __BEGIN_DECLS
39 
40 typedef	unsigned int	tcp_seq;
41 /*
42  * TCP header.
43  * Per RFC 793, September, 1981.
44  */
45 struct tcphdr {
46 	unsigned short	th_sport;	/* source port */
47 	unsigned 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 	unsigned char	th_x2:4,	/* (unused) */
52 			th_off:4;	/* data offset */
53 #endif
54 #if __BYTE_ORDER == __BIG_ENDIAN
55 	unsigned char	th_off:4,	/* data offset */
56 			th_x2:4;	/* (unused) */
57 #endif
58 	unsigned 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 	unsigned short	th_win;		/* window */
66 	unsigned short	th_sum;		/* checksum */
67 	unsigned 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 #define SOL_TCP		6	/* TCP level */
105 
106 __END_DECLS
107 
108 #endif /* netinet/tcp.h */
109