1/* $NetBSD: tcp.h,v 1.37 2021/02/03 18:13:13 roy Exp $ */
2
3/*
4 * Copyright (c) 1982, 1986, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)tcp.h 8.1 (Berkeley) 6/10/93
32 */
33
34#ifndef _NETINET_TCP_H_
35#define _NETINET_TCP_H_
36
37#include <sys/featuretest.h>
38
39#if defined(_NETBSD_SOURCE)
40#include <sys/types.h>
41
42typedef uint32_t tcp_seq;
43/*
44 * TCP header.
45 * Per RFC 793, September, 1981.
46 * Updated by RFC 3168, September, 2001.
47 */
48struct tcphdr {
49 uint16_t th_sport; /* source port */
50 uint16_t th_dport; /* destination port */
51 tcp_seq th_seq; /* sequence number */
52 tcp_seq th_ack; /* acknowledgement number */
53#if BYTE_ORDER == LITTLE_ENDIAN
54 /*LINTED non-portable bitfields*/
55 uint8_t th_x2:4, /* (unused) */
56 th_off:4; /* data offset */
57#endif
58#if BYTE_ORDER == BIG_ENDIAN
59 /*LINTED non-portable bitfields*/
60 uint8_t th_off:4, /* data offset */
61 th_x2:4; /* (unused) */
62#endif
63 uint8_t th_flags;
64#define TH_FIN 0x01 /* Final: Set on the last segment */
65#define TH_SYN 0x02 /* Synchronization: New conn with dst port */
66#define TH_RST 0x04 /* Reset: Announce to peer conn terminated */
67#define TH_PUSH 0x08 /* Push: Immediately send, don't buffer seg */
68#define TH_ACK 0x10 /* Acknowledge: Part of connection establish */
69#define TH_URG 0x20 /* Urgent: send special marked segment now */
70#define TH_ECE 0x40 /* ECN Echo */
71#define TH_CWR 0x80 /* Congestion Window Reduced */
72 uint16_t th_win; /* window */
73 uint16_t th_sum; /* checksum */
74 uint16_t th_urp; /* urgent pointer */
75};
76#ifdef __CTASSERT
77__CTASSERT(sizeof(struct tcphdr) == 20);
78#endif
79
80#define TCPOPT_EOL 0
81#define TCPOLEN_EOL 1
82#define TCPOPT_PAD 0
83#define TCPOLEN_PAD 1
84#define TCPOPT_NOP 1
85#define TCPOLEN_NOP 1
86#define TCPOPT_MAXSEG 2
87#define TCPOLEN_MAXSEG 4
88#define TCPOPT_WINDOW 3
89#define TCPOLEN_WINDOW 3
90#define TCPOPT_SACK_PERMITTED 4 /* Experimental */
91#define TCPOLEN_SACK_PERMITTED 2
92#define TCPOPT_SACK 5 /* Experimental */
93#define TCPOPT_TIMESTAMP 8
94#define TCPOLEN_TIMESTAMP 10
95#define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */
96
97#define TCPOPT_TSTAMP_HDR \
98 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
99
100#define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */
101#define TCPOLEN_SIGNATURE 18
102#define TCPOLEN_SIGLEN (TCPOLEN_SIGNATURE+2) /* padding */
103
104#define MAX_TCPOPTLEN 40 /* max # bytes that go in options */
105
106/*
107 * Default maximum segment size for TCP.
108 * This is defined by RFC 1112 Sec 4.2.2.6.
109 */
110#define TCP_MSS 536
111
112#define TCP_MINMSS 216
113
114#define TCP_MAXWIN 65535 /* largest value for (unscaled) window */
115
116#define TCP_MAX_WINSHIFT 14 /* maximum window shift */
117
118#define TCP_MAXBURST 4 /* maximum segments in a burst */
119
120#endif /* _NETBSD_SOURCE */
121
122/*
123 * User-settable options (used with setsockopt).
124 */
125#define TCP_NODELAY 1 /* don't delay send to coalesce packets */
126#define TCP_MAXSEG 2 /* set maximum segment size */
127#define TCP_KEEPIDLE 3
128#ifdef notyet
129#define TCP_NOPUSH 4 /* reserved for FreeBSD compat */
130#endif
131#define TCP_KEEPINTVL 5
132#define TCP_KEEPCNT 6
133#define TCP_KEEPINIT 7
134#ifdef notyet
135#define TCP_NOOPT 8 /* reserved for FreeBSD compat */
136#endif
137#define TCP_INFO 9 /* retrieve tcp_info structure */
138#define TCP_MD5SIG 0x10 /* use MD5 digests (RFC2385) */
139#define TCP_CONGCTL 0x20 /* selected congestion control */
140
141#define TCPI_OPT_TIMESTAMPS 0x01
142#define TCPI_OPT_SACK 0x02
143#define TCPI_OPT_WSCALE 0x04
144#define TCPI_OPT_ECN 0x08
145#define TCPI_OPT_TOE 0x10
146
147/*
148 * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits
149 * the caller to query certain information about the state of a TCP
150 * connection. We provide an overlapping set of fields with the Linux
151 * implementation, but since this is a fixed size structure, room has been
152 * left for growth. In order to maximize potential future compatibility with
153 * the Linux API, the same variable names and order have been adopted, and
154 * padding left to make room for omitted fields in case they are added later.
155 *
156 * XXX: This is currently an unstable ABI/API, in that it is expected to
157 * change.
158 */
159struct tcp_info {
160 uint8_t tcpi_state; /* TCP FSM state. */
161 uint8_t __tcpi_ca_state;
162 uint8_t __tcpi_retransmits;
163 uint8_t __tcpi_probes;
164 uint8_t __tcpi_backoff;
165 uint8_t tcpi_options; /* Options enabled on conn. */
166 /*LINTED: non-portable bitfield*/
167 uint8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */
168 /*LINTED: non-portable bitfield*/
169 tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */
170
171 uint32_t tcpi_rto; /* Retransmission timeout (usec). */
172 uint32_t __tcpi_ato;
173 uint32_t tcpi_snd_mss; /* Max segment size for send. */
174 uint32_t tcpi_rcv_mss; /* Max segment size for receive. */
175
176 uint32_t __tcpi_unacked;
177 uint32_t __tcpi_sacked;
178 uint32_t __tcpi_lost;
179 uint32_t __tcpi_retrans;
180 uint32_t __tcpi_fackets;
181
182 /* Times; measurements in usecs. */
183 uint32_t __tcpi_last_data_sent;
184 uint32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */
185 uint32_t tcpi_last_data_recv; /* Time since last recv data. */
186 uint32_t __tcpi_last_ack_recv;
187
188 /* Metrics; variable units. */
189 uint32_t __tcpi_pmtu;
190 uint32_t __tcpi_rcv_ssthresh;
191 uint32_t tcpi_rtt; /* Smoothed RTT in usecs. */
192 uint32_t tcpi_rttvar; /* RTT variance in usecs. */
193 uint32_t tcpi_snd_ssthresh; /* Slow start threshold. */
194 uint32_t tcpi_snd_cwnd; /* Send congestion window. */
195 uint32_t __tcpi_advmss;
196 uint32_t __tcpi_reordering;
197
198 uint32_t __tcpi_rcv_rtt;
199 uint32_t tcpi_rcv_space; /* Advertised recv window. */
200
201 /* FreeBSD/NetBSD extensions to tcp_info. */
202 uint32_t tcpi_snd_wnd; /* Advertised send window. */
203 uint32_t tcpi_snd_bwnd; /* No longer used. */
204 uint32_t tcpi_snd_nxt; /* Next egress seqno */
205 uint32_t tcpi_rcv_nxt; /* Next ingress seqno */
206 uint32_t tcpi_toe_tid; /* HWTID for TOE endpoints */
207 uint32_t tcpi_snd_rexmitpack; /* Retransmitted packets */
208 uint32_t tcpi_rcv_ooopack; /* Out-of-order packets */
209 uint32_t tcpi_snd_zerowin; /* Zero-sized windows sent */
210
211 /* Padding to grow without breaking ABI. */
212 uint32_t __tcpi_pad[26]; /* Padding. */
213};
214
215#endif /* !_NETINET_TCP_H_ */