386BSD 0.1 development
[unix-history] / usr / src / sys.386bsd / netinet / tcp.h
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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 * @(#)tcp.h 7.7 (Berkeley) 6/28/90
34 */
35
36typedef u_long tcp_seq;
37/*
38 * TCP header.
39 * Per RFC 793, September, 1981.
40 */
41struct tcphdr {
42 u_short th_sport; /* source port */
43 u_short th_dport; /* destination port */
44 tcp_seq th_seq; /* sequence number */
45 tcp_seq th_ack; /* acknowledgement number */
46#if BYTE_ORDER == LITTLE_ENDIAN
47 u_char th_x2:4, /* (unused) */
48 th_off:4; /* data offset */
49#endif
50#if BYTE_ORDER == BIG_ENDIAN
51 u_char th_off:4, /* data offset */
52 th_x2:4; /* (unused) */
53#endif
54 u_char th_flags;
55#define TH_FIN 0x01
56#define TH_SYN 0x02
57#define TH_RST 0x04
58#define TH_PUSH 0x08
59#define TH_ACK 0x10
60#define TH_URG 0x20
61 u_short th_win; /* window */
62 u_short th_sum; /* checksum */
63 u_short th_urp; /* urgent pointer */
64};
65
66#define TCPOPT_EOL 0
67#define TCPOPT_NOP 1
68#define TCPOPT_MAXSEG 2
69
70/*
71 * Default maximum segment size for TCP.
72 * With an IP MSS of 576, this is 536,
73 * but 512 is probably more convenient.
74 * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
75 */
76#define TCP_MSS 512
77
78#define TCP_MAXWIN 65535 /* largest value for window */
79
80/*
81 * User-settable options (used with setsockopt).
82 */
83#define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */
84#define TCP_MAXSEG 0x02 /* set maximum segment size */