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_ */ 216