1 /* $OpenBSD: tcp.h,v 1.24 2023/05/19 01:04:39 guenther Exp $ */ 2 /* $NetBSD: tcp.h,v 1.8 1995/04/17 05:32:58 cgd Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)tcp.h 8.1 (Berkeley) 6/10/93 33 */ 34 35 #ifndef _NETINET_TCP_H_ 36 #define _NETINET_TCP_H_ 37 38 #include <sys/cdefs.h> 39 40 #if __BSD_VISIBLE 41 42 typedef u_int32_t tcp_seq; 43 44 /* 45 * TCP header. 46 * Per RFC 793, September, 1981. 47 */ 48 struct tcphdr { 49 u_int16_t th_sport; /* source port */ 50 u_int16_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 u_int32_t th_x2:4, /* (unused) */ 55 th_off:4; /* data offset */ 56 #endif 57 #if _BYTE_ORDER == _BIG_ENDIAN 58 u_int32_t th_off:4, /* data offset */ 59 th_x2:4; /* (unused) */ 60 #endif 61 u_int8_t th_flags; 62 #define TH_FIN 0x01 63 #define TH_SYN 0x02 64 #define TH_RST 0x04 65 #define TH_PUSH 0x08 66 #define TH_ACK 0x10 67 #define TH_URG 0x20 68 #define TH_ECE 0x40 69 #define TH_CWR 0x80 70 u_int16_t th_win; /* window */ 71 u_int16_t th_sum; /* checksum */ 72 u_int16_t th_urp; /* urgent pointer */ 73 }; 74 #define th_reseqlen th_urp /* TCP data length for 75 resequencing/reassembly */ 76 77 #define TCPOPT_EOL 0 78 #define TCPOPT_NOP 1 79 #define TCPOPT_MAXSEG 2 80 #define TCPOLEN_MAXSEG 4 81 #define TCPOPT_WINDOW 3 82 #define TCPOLEN_WINDOW 3 83 #define TCPOPT_SACK_PERMITTED 4 /* Experimental */ 84 #define TCPOLEN_SACK_PERMITTED 2 85 #define TCPOPT_SACK 5 /* Experimental */ 86 #define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ 87 #define TCPOPT_TIMESTAMP 8 88 #define TCPOLEN_TIMESTAMP 10 89 #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 90 #define TCPOPT_SIGNATURE 19 91 #define TCPOLEN_SIGNATURE 18 92 #define TCPOLEN_SIGLEN (TCPOLEN_SIGNATURE+2) /* padding */ 93 94 #define MAX_TCPOPTLEN 40 /* Absolute maximum TCP options len */ 95 96 #define TCPOPT_TSTAMP_HDR \ 97 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP) 98 99 /* Option definitions */ 100 #define TCPOPT_SACK_PERMIT_HDR \ 101 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED) 102 #define TCPOPT_SACK_HDR (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8) 103 /* Miscellaneous constants */ 104 #define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at sender side */ 105 #define TCP_MAX_SACK 3 /* Max # SACKs sent in any segment */ 106 #define TCP_SACKHOLE_LIMIT 128 /* Max # SACK holes per connection */ 107 108 /* 109 * Default maximum segment size for TCP. 110 * With an IP MSS of 576, this is 536, 111 * but 512 is probably more convenient. 112 * This should be defined as min(512, IP_MSS - sizeof (struct tcpiphdr)). 113 */ 114 #define TCP_MSS 512 115 116 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 117 118 #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 119 120 /* 121 * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits 122 * the caller to query certain information about the state of a TCP 123 * connection. Provide an overlapping set of fields with the Linux 124 * implementation, but at the same time add a lot of OpenBSD specific 125 * extra information. 126 */ 127 struct tcp_info { 128 uint8_t tcpi_state; /* TCP FSM state. */ 129 uint8_t __tcpi_ca_state; 130 uint8_t __tcpi_retransmits; 131 uint8_t __tcpi_probes; 132 uint8_t __tcpi_backoff; 133 uint8_t tcpi_options; /* Options enabled on conn. */ 134 #define TCPI_OPT_TIMESTAMPS 0x01 135 #define TCPI_OPT_SACK 0x02 136 #define TCPI_OPT_WSCALE 0x04 137 #define TCPI_OPT_ECN 0x08 138 #define TCPI_OPT_TOE 0x10 139 uint8_t tcpi_snd_wscale; /* RFC1323 send shift value. */ 140 uint8_t tcpi_rcv_wscale; /* RFC1323 recv shift value. */ 141 142 uint32_t tcpi_rto; /* Retransmission timeout (usec). */ 143 uint32_t __tcpi_ato; 144 uint32_t tcpi_snd_mss; /* Max segment size for send. */ 145 uint32_t tcpi_rcv_mss; /* Max segment size for recv. */ 146 147 uint32_t __tcpi_unacked; 148 uint32_t __tcpi_sacked; 149 uint32_t __tcpi_lost; 150 uint32_t __tcpi_retrans; 151 uint32_t __tcpi_fackets; 152 153 /* Times; measurements in usecs. */ 154 uint32_t tcpi_last_data_sent; /* since last sent data. */ 155 uint32_t tcpi_last_ack_sent; /* since last sent ack. */ 156 uint32_t tcpi_last_data_recv; /* since last recv data. */ 157 uint32_t tcpi_last_ack_recv; /* since last recv ack. */ 158 159 /* Metrics; variable units. */ 160 uint32_t __tcpi_pmtu; 161 uint32_t __tcpi_rcv_ssthresh; 162 uint32_t tcpi_rtt; /* Smoothed RTT in usecs. */ 163 uint32_t tcpi_rttvar; /* RTT variance in usecs. */ 164 uint32_t tcpi_snd_ssthresh; /* Slow start threshold. */ 165 uint32_t tcpi_snd_cwnd; /* Send congestion window. */ 166 uint32_t __tcpi_advmss; 167 uint32_t __tcpi_reordering; 168 169 uint32_t __tcpi_rcv_rtt; 170 uint32_t tcpi_rcv_space; /* Advertised recv window. */ 171 172 /* 173 * Members below this point are only set if process is privileged, 174 * otherwise values will be 0. 175 */ 176 177 /* FreeBSD/NetBSD extensions to tcp_info. */ 178 uint32_t tcpi_snd_wnd; /* Advertised send window. */ 179 uint32_t tcpi_snd_nxt; /* Next egress seqno */ 180 uint32_t tcpi_rcv_nxt; /* Next ingress seqno */ 181 uint32_t tcpi_toe_tid; /* HWTID for TOE endpoints */ 182 uint32_t tcpi_snd_rexmitpack; /* Retransmitted packets */ 183 uint32_t tcpi_rcv_ooopack; /* Out-of-order packets */ 184 uint32_t tcpi_snd_zerowin; /* Zero-sized windows sent */ 185 186 /* OpenBSD extensions */ 187 uint32_t tcpi_rttmin; 188 uint32_t tcpi_max_sndwnd; 189 uint32_t tcpi_rcv_adv; 190 uint32_t tcpi_rcv_up; 191 uint32_t tcpi_snd_una; 192 uint32_t tcpi_snd_up; 193 uint32_t tcpi_snd_wl1; 194 uint32_t tcpi_snd_wl2; 195 uint32_t tcpi_snd_max; 196 uint32_t tcpi_ts_recent; 197 uint32_t tcpi_ts_recent_age; 198 uint32_t tcpi_rfbuf_cnt; 199 uint32_t tcpi_rfbuf_ts; 200 uint32_t tcpi_so_rcv_sb_cc; 201 uint32_t tcpi_so_rcv_sb_hiwat; 202 uint32_t tcpi_so_rcv_sb_lowat; 203 uint32_t tcpi_so_rcv_sb_wat; 204 uint32_t tcpi_so_snd_sb_cc; 205 uint32_t tcpi_so_snd_sb_hiwat; 206 uint32_t tcpi_so_snd_sb_lowat; 207 uint32_t tcpi_so_snd_sb_wat; 208 }; 209 210 #endif /* __BSD_VISIBLE */ 211 212 /* 213 * User-settable options (used with setsockopt). 214 */ 215 #define TCP_NODELAY 0x01 /* don't delay send to coalesce pkts */ 216 #define TCP_MAXSEG 0x02 /* set maximum segment size */ 217 #define TCP_MD5SIG 0x04 /* enable TCP MD5 signature option */ 218 #define TCP_SACK_ENABLE 0x08 /* enable SACKs (if disabled by def.) */ 219 #define TCP_INFO 0x09 /* retrieve tcp_info structure */ 220 #define TCP_NOPUSH 0x10 /* don't push last block of write */ 221 222 #endif /* _NETINET_TCP_H_ */ 223