1 /* $NetBSD: tcp.h,v 1.38 2026/01/08 15:39:07 nia 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 #include <sys/endian.h> 42 43 typedef uint32_t tcp_seq; 44 /* 45 * TCP header. 46 * Per RFC 793, September, 1981. 47 * Updated by RFC 3168, September, 2001. 48 */ 49 struct tcphdr { 50 uint16_t th_sport; /* source port */ 51 uint16_t th_dport; /* destination port */ 52 tcp_seq th_seq; /* sequence number */ 53 tcp_seq th_ack; /* acknowledgement number */ 54 #if BYTE_ORDER == LITTLE_ENDIAN 55 /*LINTED non-portable bitfields*/ 56 uint8_t th_x2:4, /* (unused) */ 57 th_off:4; /* data offset */ 58 #endif 59 #if BYTE_ORDER == BIG_ENDIAN 60 /*LINTED non-portable bitfields*/ 61 uint8_t th_off:4, /* data offset */ 62 th_x2:4; /* (unused) */ 63 #endif 64 uint8_t th_flags; 65 #define TH_FIN 0x01 /* Final: Set on the last segment */ 66 #define TH_SYN 0x02 /* Synchronization: New conn with dst port */ 67 #define TH_RST 0x04 /* Reset: Announce to peer conn terminated */ 68 #define TH_PUSH 0x08 /* Push: Immediately send, don't buffer seg */ 69 #define TH_ACK 0x10 /* Acknowledge: Part of connection establish */ 70 #define TH_URG 0x20 /* Urgent: send special marked segment now */ 71 #define TH_ECE 0x40 /* ECN Echo */ 72 #define TH_CWR 0x80 /* Congestion Window Reduced */ 73 uint16_t th_win; /* window */ 74 uint16_t th_sum; /* checksum */ 75 uint16_t th_urp; /* urgent pointer */ 76 }; 77 #ifdef __CTASSERT 78 __CTASSERT(sizeof(struct tcphdr) == 20); 79 #endif 80 81 #define TCPOPT_EOL 0 82 #define TCPOLEN_EOL 1 83 #define TCPOPT_PAD 0 84 #define TCPOLEN_PAD 1 85 #define TCPOPT_NOP 1 86 #define TCPOLEN_NOP 1 87 #define TCPOPT_MAXSEG 2 88 #define TCPOLEN_MAXSEG 4 89 #define TCPOPT_WINDOW 3 90 #define TCPOLEN_WINDOW 3 91 #define TCPOPT_SACK_PERMITTED 4 /* Experimental */ 92 #define TCPOLEN_SACK_PERMITTED 2 93 #define TCPOPT_SACK 5 /* Experimental */ 94 #define TCPOPT_TIMESTAMP 8 95 #define TCPOLEN_TIMESTAMP 10 96 #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 97 98 #define TCPOPT_TSTAMP_HDR \ 99 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP) 100 101 #define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */ 102 #define TCPOLEN_SIGNATURE 18 103 #define TCPOLEN_SIGLEN (TCPOLEN_SIGNATURE+2) /* padding */ 104 105 #define MAX_TCPOPTLEN 40 /* max # bytes that go in options */ 106 107 /* 108 * Default maximum segment size for TCP. 109 * This is defined by RFC 1112 Sec 4.2.2.6. 110 */ 111 #define TCP_MSS 536 112 113 #define TCP_MINMSS 216 114 115 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 116 117 #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 118 119 #define TCP_MAXBURST 4 /* maximum segments in a burst */ 120 121 #endif /* _NETBSD_SOURCE */ 122 123 /* 124 * User-settable options (used with setsockopt). 125 */ 126 #define TCP_NODELAY 1 /* don't delay send to coalesce packets */ 127 #define TCP_MAXSEG 2 /* set maximum segment size */ 128 #define TCP_KEEPIDLE 3 129 #ifdef notyet 130 #define TCP_NOPUSH 4 /* reserved for FreeBSD compat */ 131 #endif 132 #define TCP_KEEPINTVL 5 133 #define TCP_KEEPCNT 6 134 #define TCP_KEEPINIT 7 135 #ifdef notyet 136 #define TCP_NOOPT 8 /* reserved for FreeBSD compat */ 137 #endif 138 #define TCP_INFO 9 /* retrieve tcp_info structure */ 139 #define TCP_MD5SIG 0x10 /* use MD5 digests (RFC2385) */ 140 #define TCP_CONGCTL 0x20 /* selected congestion control */ 141 142 #define TCPI_OPT_TIMESTAMPS 0x01 143 #define TCPI_OPT_SACK 0x02 144 #define TCPI_OPT_WSCALE 0x04 145 #define TCPI_OPT_ECN 0x08 146 #define TCPI_OPT_TOE 0x10 147 148 /* 149 * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits 150 * the caller to query certain information about the state of a TCP 151 * connection. We provide an overlapping set of fields with the Linux 152 * implementation, but since this is a fixed size structure, room has been 153 * left for growth. In order to maximize potential future compatibility with 154 * the Linux API, the same variable names and order have been adopted, and 155 * padding left to make room for omitted fields in case they are added later. 156 * 157 * XXX: This is currently an unstable ABI/API, in that it is expected to 158 * change. 159 */ 160 struct tcp_info { 161 uint8_t tcpi_state; /* TCP FSM state. */ 162 uint8_t __tcpi_ca_state; 163 uint8_t __tcpi_retransmits; 164 uint8_t __tcpi_probes; 165 uint8_t __tcpi_backoff; 166 uint8_t tcpi_options; /* Options enabled on conn. */ 167 /*LINTED: non-portable bitfield*/ 168 uint8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */ 169 /*LINTED: non-portable bitfield*/ 170 tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */ 171 172 uint32_t tcpi_rto; /* Retransmission timeout (usec). */ 173 uint32_t __tcpi_ato; 174 uint32_t tcpi_snd_mss; /* Max segment size for send. */ 175 uint32_t tcpi_rcv_mss; /* Max segment size for receive. */ 176 177 uint32_t __tcpi_unacked; 178 uint32_t __tcpi_sacked; 179 uint32_t __tcpi_lost; 180 uint32_t __tcpi_retrans; 181 uint32_t __tcpi_fackets; 182 183 /* Times; measurements in usecs. */ 184 uint32_t __tcpi_last_data_sent; 185 uint32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */ 186 uint32_t tcpi_last_data_recv; /* Time since last recv data. */ 187 uint32_t __tcpi_last_ack_recv; 188 189 /* Metrics; variable units. */ 190 uint32_t __tcpi_pmtu; 191 uint32_t __tcpi_rcv_ssthresh; 192 uint32_t tcpi_rtt; /* Smoothed RTT in usecs. */ 193 uint32_t tcpi_rttvar; /* RTT variance in usecs. */ 194 uint32_t tcpi_snd_ssthresh; /* Slow start threshold. */ 195 uint32_t tcpi_snd_cwnd; /* Send congestion window. */ 196 uint32_t __tcpi_advmss; 197 uint32_t __tcpi_reordering; 198 199 uint32_t __tcpi_rcv_rtt; 200 uint32_t tcpi_rcv_space; /* Advertised recv window. */ 201 202 /* FreeBSD/NetBSD extensions to tcp_info. */ 203 uint32_t tcpi_snd_wnd; /* Advertised send window. */ 204 uint32_t tcpi_snd_bwnd; /* No longer used. */ 205 uint32_t tcpi_snd_nxt; /* Next egress seqno */ 206 uint32_t tcpi_rcv_nxt; /* Next ingress seqno */ 207 uint32_t tcpi_toe_tid; /* HWTID for TOE endpoints */ 208 uint32_t tcpi_snd_rexmitpack; /* Retransmitted packets */ 209 uint32_t tcpi_rcv_ooopack; /* Out-of-order packets */ 210 uint32_t tcpi_snd_zerowin; /* Zero-sized windows sent */ 211 212 /* Padding to grow without breaking ABI. */ 213 uint32_t __tcpi_pad[26]; /* Padding. */ 214 }; 215 216 #endif /* !_NETINET_TCP_H_ */ 217
Indexes created Sat Feb 21 08:20:20 UTC 2026