tcp.h revision 166433
1/*- 2 * Copyright (c) 1982, 1986, 1993 3 * The Regents of the University of California. 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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp.h 8.1 (Berkeley) 6/10/93 30 * $FreeBSD: head/sys/netinet/tcp.h 166433 2007-02-02 18:34:18Z bms $ 31 */ 32 33#ifndef _NETINET_TCP_H_ 34#define _NETINET_TCP_H_ 35 36#include <sys/cdefs.h> 37 38#if __BSD_VISIBLE 39 40typedef u_int32_t tcp_seq; 41 42#define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */ 43#define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */ 44 45/* 46 * TCP header. 47 * Per RFC 793, September, 1981. 48 */ 49struct tcphdr { 50 u_short th_sport; /* source port */ 51 u_short 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 u_int th_x2:4, /* (unused) */ 56 th_off:4; /* data offset */ 57#endif 58#if BYTE_ORDER == BIG_ENDIAN 59 u_int th_off:4, /* data offset */ 60 th_x2:4; /* (unused) */ 61#endif 62 u_char th_flags; 63#define TH_FIN 0x01 64#define TH_SYN 0x02 65#define TH_RST 0x04 66#define TH_PUSH 0x08 67#define TH_ACK 0x10 68#define TH_URG 0x20 69#define TH_ECE 0x40 70#define TH_CWR 0x80 71#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG|TH_ECE|TH_CWR) 72 73 u_short th_win; /* window */ 74 u_short th_sum; /* checksum */ 75 u_short th_urp; /* urgent pointer */ 76}; 77 78#define TCPOPT_EOL 0 79#define TCPOPT_NOP 1 80#define TCPOPT_MAXSEG 2 81#define TCPOLEN_MAXSEG 4 82#define TCPOPT_WINDOW 3 83#define TCPOLEN_WINDOW 3 84#define TCPOPT_SACK_PERMITTED 4 /* Experimental */ 85#define TCPOLEN_SACK_PERMITTED 2 86#define TCPOPT_SACK 5 /* Experimental */ 87#define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ 88#define TCPOPT_TIMESTAMP 8 89#define TCPOLEN_TIMESTAMP 10 90#define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 91#define TCPOPT_TSTAMP_HDR \ 92 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP) 93 94#define MAX_TCPOPTLEN 40 /* Absolute maximum TCP options len */ 95 96#define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */ 97#define TCPOLEN_SIGNATURE 18 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 receiver side */ 105#define TCP_MAX_SACK 4 /* MAX # SACKs sent in any segment */ 106 107 108/* 109 * Default maximum segment size for TCP. 110 * With an IP MTU 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 * TCP_MINMSS is defined to be 216 which is fine for the smallest 117 * link MTU (256 bytes, AX.25 packet radio) in the Internet. 118 * However it is very unlikely to come across such low MTU interfaces 119 * these days (anno dato 2003). 120 * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments. 121 * Setting this to "0" disables the minmss check. 122 */ 123#define TCP_MINMSS 216 124/* 125 * TCP_MINMSSOVERLOAD is defined to be 1000 which should cover any type 126 * of interactive TCP session. 127 * See tcp_subr.c tcp_minmssoverload SYSCTL declaration and tcp_input.c 128 * for more comments. 129 * Setting this to "0" disables the minmssoverload check. 130 */ 131#define TCP_MINMSSOVERLOAD 0 /* XXX: Disabled until refined */ 132 133/* 134 * Default maximum segment size for TCP6. 135 * With an IP6 MSS of 1280, this is 1220, 136 * but 1024 is probably more convenient. (xxx kazu in doubt) 137 * This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr)) 138 */ 139#define TCP6_MSS 1024 140 141#define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 142#define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */ 143 144#define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 145 146#define TCP_MAXBURST 4 /* maximum segments in a burst */ 147 148#define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */ 149#define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr)) 150 /* max space left for options */ 151#endif /* __BSD_VISIBLE */ 152 153/* 154 * User-settable options (used with setsockopt). 155 */ 156#define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */ 157#if __BSD_VISIBLE 158#define TCP_MAXSEG 0x02 /* set maximum segment size */ 159#define TCP_NOPUSH 0x04 /* don't push last block of write */ 160#define TCP_NOOPT 0x08 /* don't use TCP options */ 161#define TCP_MD5SIG 0x10 /* use MD5 digests (RFC2385) */ 162#define TCP_INFO 0x20 /* retrieve tcp_info structure */ 163 164#define TCPI_OPT_TIMESTAMPS 0x01 165#define TCPI_OPT_SACK 0x02 166#define TCPI_OPT_WSCALE 0x04 167#define TCPI_OPT_ECN 0x08 168 169/* 170 * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits 171 * the caller to query certain information about the state of a TCP 172 * connection. We provide an overlapping set of fields with the Linux 173 * implementation, but since this is a fixed size structure, room has been 174 * left for growth. In order to maximize potential future compatibility with 175 * the Linux API, the same variable names and order have been adopted, and 176 * padding left to make room for omitted fields in case they are added later. 177 * 178 * XXX: This is currently an unstable ABI/API, in that it is expected to 179 * change. 180 */ 181struct tcp_info { 182 u_int8_t tcpi_state; /* TCP FSM state. */ 183 u_int8_t __tcpi_ca_state; 184 u_int8_t __tcpi_retransmits; 185 u_int8_t __tcpi_probes; 186 u_int8_t __tcpi_backoff; 187 u_int8_t tcpi_options; /* Options enabled on conn. */ 188 u_int8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */ 189 tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */ 190 191 u_int32_t __tcpi_rto; 192 u_int32_t __tcpi_ato; 193 u_int32_t __tcpi_snd_mss; 194 u_int32_t __tcpi_rcv_mss; 195 196 u_int32_t __tcpi_unacked; 197 u_int32_t __tcpi_sacked; 198 u_int32_t __tcpi_lost; 199 u_int32_t __tcpi_retrans; 200 u_int32_t __tcpi_fackets; 201 202 /* Times; measurements in usecs. */ 203 u_int32_t __tcpi_last_data_sent; 204 u_int32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */ 205 u_int32_t __tcpi_last_data_recv; 206 u_int32_t __tcpi_last_ack_recv; 207 208 /* Metrics; variable units. */ 209 u_int32_t __tcpi_pmtu; 210 u_int32_t __tcpi_rcv_ssthresh; 211 u_int32_t tcpi_rtt; /* Smoothed RTT in usecs. */ 212 u_int32_t tcpi_rttvar; /* RTT variance in usecs. */ 213 u_int32_t tcpi_snd_ssthresh; /* Slow start threshold. */ 214 u_int32_t tcpi_snd_cwnd; /* Send congestion window. */ 215 u_int32_t __tcpi_advmss; 216 u_int32_t __tcpi_reordering; 217 218 u_int32_t __tcpi_rcv_rtt; 219 u_int32_t tcpi_rcv_space; /* Advertised recv window. */ 220 221 /* FreeBSD extensions to tcp_info. */ 222 u_int32_t tcpi_snd_wnd; /* Advertised send window. */ 223 u_int32_t tcpi_snd_bwnd; /* Bandwidth send window. */ 224 225 /* Padding to grow without breaking ABI. */ 226 u_int32_t __tcpi_pad[32]; /* Padding. */ 227}; 228#endif 229 230#endif /* !_NETINET_TCP_H_ */ 231