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 * $FreeBSD$ 31 */ 32 33 #ifndef _NETINET_TCP_H_ 34 #define _NETINET_TCP_H_ 35 36 #include <sys/cdefs.h> 37 38 #if __BSD_VISIBLE 39 40 typedef 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 */ 49 struct 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 #define PRINT_TH_FLAGS "\20\1FIN\2SYN\3RST\4PUSH\5ACK\6URG\7ECE\10CWR" 73 74 u_short th_win; /* window */ 75 u_short th_sum; /* checksum */ 76 u_short th_urp; /* urgent pointer */ 77 }; 78 79 #define TCPOPT_EOL 0 80 #define TCPOLEN_EOL 1 81 #define TCPOPT_PAD 0 /* padding after EOL */ 82 #define TCPOLEN_PAD 1 83 #define TCPOPT_NOP 1 84 #define TCPOLEN_NOP 1 85 #define TCPOPT_MAXSEG 2 86 #define TCPOLEN_MAXSEG 4 87 #define TCPOPT_WINDOW 3 88 #define TCPOLEN_WINDOW 3 89 #define TCPOPT_SACK_PERMITTED 4 90 #define TCPOLEN_SACK_PERMITTED 2 91 #define TCPOPT_SACK 5 92 #define TCPOLEN_SACKHDR 2 93 #define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ 94 #define TCPOPT_TIMESTAMP 8 95 #define TCPOLEN_TIMESTAMP 10 96 #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 97 #define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */ 98 #define TCPOLEN_SIGNATURE 18 99 100 /* Miscellaneous constants */ 101 #define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at receiver side */ 102 #define TCP_MAX_SACK 4 /* MAX # SACKs sent in any segment */ 103 104 105 /* 106 * Default maximum segment size for TCP. 107 * With an IP MTU of 576, this is 536, 108 * but 512 is probably more convenient. 109 * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)). 110 */ 111 #define TCP_MSS 512 112 /* 113 * TCP_MINMSS is defined to be 216 which is fine for the smallest 114 * link MTU (256 bytes, AX.25 packet radio) in the Internet. 115 * However it is very unlikely to come across such low MTU interfaces 116 * these days (anno dato 2003). 117 * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments. 118 * Setting this to "0" disables the minmss check. 119 */ 120 #define TCP_MINMSS 216 121 122 /* 123 * Default maximum segment size for TCP6. 124 * With an IP6 MSS of 1280, this is 1220, 125 * but 1024 is probably more convenient. (xxx kazu in doubt) 126 * This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr)) 127 */ 128 #define TCP6_MSS 1024 129 130 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 131 #define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */ 132 133 #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 134 135 #define TCP_MAXBURST 4 /* maximum segments in a burst */ 136 137 #define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */ 138 #define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr)) 139 /* max space left for options */ 140 #endif /* __BSD_VISIBLE */ 141 142 /* 143 * User-settable options (used with setsockopt). 144 */ 145 #define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */ 146 #if __BSD_VISIBLE 147 #define TCP_MAXSEG 0x02 /* set maximum segment size */ 148 #define TCP_NOPUSH 0x04 /* don't push last block of write */ 149 #define TCP_NOOPT 0x08 /* don't use TCP options */ 150 #define TCP_MD5SIG 0x10 /* use MD5 digests (RFC2385) */ 151 #define TCP_INFO 0x20 /* retrieve tcp_info structure */ 152 #define TCP_CONGESTION 0x40 /* get/set congestion control algorithm */ 153 154 #define TCP_CA_NAME_MAX 16 /* max congestion control name length */ 155 156 #define TCPI_OPT_TIMESTAMPS 0x01 157 #define TCPI_OPT_SACK 0x02 158 #define TCPI_OPT_WSCALE 0x04 159 #define TCPI_OPT_ECN 0x08 160 161 /* 162 * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits 163 * the caller to query certain information about the state of a TCP 164 * connection. We provide an overlapping set of fields with the Linux 165 * implementation, but since this is a fixed size structure, room has been 166 * left for growth. In order to maximize potential future compatibility with 167 * the Linux API, the same variable names and order have been adopted, and 168 * padding left to make room for omitted fields in case they are added later. 169 * 170 * XXX: This is currently an unstable ABI/API, in that it is expected to 171 * change. 172 */ 173 struct tcp_info { 174 u_int8_t tcpi_state; /* TCP FSM state. */ 175 u_int8_t __tcpi_ca_state; 176 u_int8_t __tcpi_retransmits; 177 u_int8_t __tcpi_probes; 178 u_int8_t __tcpi_backoff; 179 u_int8_t tcpi_options; /* Options enabled on conn. */ 180 u_int8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */ 181 tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */ 182 183 u_int32_t __tcpi_rto; 184 u_int32_t __tcpi_ato; 185 u_int32_t __tcpi_snd_mss; 186 u_int32_t __tcpi_rcv_mss; 187 188 u_int32_t __tcpi_unacked; 189 u_int32_t __tcpi_sacked; 190 u_int32_t __tcpi_lost; 191 u_int32_t __tcpi_retrans; 192 u_int32_t __tcpi_fackets; 193 194 /* Times; measurements in usecs. */ 195 u_int32_t __tcpi_last_data_sent; 196 u_int32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */ 197 u_int32_t __tcpi_last_data_recv; 198 u_int32_t __tcpi_last_ack_recv; 199 200 /* Metrics; variable units. */ 201 u_int32_t __tcpi_pmtu; 202 u_int32_t __tcpi_rcv_ssthresh; 203 u_int32_t tcpi_rtt; /* Smoothed RTT in usecs. */ 204 u_int32_t tcpi_rttvar; /* RTT variance in usecs. */ 205 u_int32_t tcpi_snd_ssthresh; /* Slow start threshold. */ 206 u_int32_t tcpi_snd_cwnd; /* Send congestion window. */ 207 u_int32_t __tcpi_advmss; 208 u_int32_t __tcpi_reordering; 209 210 u_int32_t __tcpi_rcv_rtt; 211 u_int32_t tcpi_rcv_space; /* Advertised recv window. */ 212 213 /* FreeBSD extensions to tcp_info. */ 214 u_int32_t tcpi_snd_wnd; /* Advertised send window. */ 215 u_int32_t tcpi_snd_bwnd; /* Bandwidth send window. */ 216 217 /* Padding to grow without breaking ABI. */ 218 u_int32_t __tcpi_pad[32]; /* Padding. */ 219 }; 220 #endif 221 222 #endif /* !_NETINET_TCP_H_ */ 223