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#include <sys/types.h> 38 39#if __BSD_VISIBLE 40 41typedef u_int32_t tcp_seq; 42 43#define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */ 44#define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */ 45 46/* 47 * TCP header. 48 * Per RFC 793, September, 1981. 49 */ 50struct tcphdr { 51 u_short th_sport; /* source port */ 52 u_short th_dport; /* destination port */ 53 tcp_seq th_seq; /* sequence number */ 54 tcp_seq th_ack; /* acknowledgement number */ 55#if BYTE_ORDER == LITTLE_ENDIAN 56 u_char th_x2:4, /* (unused) */ 57 th_off:4; /* data offset */ 58#endif 59#if BYTE_ORDER == BIG_ENDIAN 60 u_char th_off:4, /* data offset */ 61 th_x2:4; /* (unused) */ 62#endif 63 u_char th_flags; 64#define TH_FIN 0x01 65#define TH_SYN 0x02 66#define TH_RST 0x04 67#define TH_PUSH 0x08 68#define TH_ACK 0x10 69#define TH_URG 0x20 70#define TH_ECE 0x40 71#define TH_CWR 0x80 72#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG|TH_ECE|TH_CWR) 73#define PRINT_TH_FLAGS "\20\1FIN\2SYN\3RST\4PUSH\5ACK\6URG\7ECE\10CWR" 74 75 u_short th_win; /* window */ 76 u_short th_sum; /* checksum */ 77 u_short th_urp; /* urgent pointer */ 78}; 79 80#define TCPOPT_EOL 0 81#define TCPOLEN_EOL 1 82#define TCPOPT_PAD 0 /* padding after EOL */ 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 91#define TCPOLEN_SACK_PERMITTED 2 92#define TCPOPT_SACK 5 93#define TCPOLEN_SACKHDR 2 94#define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ 95#define TCPOPT_TIMESTAMP 8 96#define TCPOLEN_TIMESTAMP 10 97#define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 98#define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */ 99#define TCPOLEN_SIGNATURE 18 100#define TCPOPT_FAST_OPEN 34 101#define TCPOLEN_FAST_OPEN_EMPTY 2 102#define TCPOLEN_FAST_OPEN_MIN 6 103#define TCPOLEN_FAST_OPEN_MAX 18 104 105/* Miscellaneous constants */ 106#define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at receiver side */ 107#define TCP_MAX_SACK 4 /* MAX # SACKs sent in any segment */ 108 109 110/* 111 * The default maximum segment size (MSS) to be used for new TCP connections 112 * when path MTU discovery is not enabled. 113 * 114 * RFC879 derives the default MSS from the largest datagram size hosts are 115 * minimally required to handle directly or through IP reassembly minus the 116 * size of the IP and TCP header. With IPv6 the minimum MTU is specified 117 * in RFC2460. 118 * 119 * For IPv4 the MSS is 576 - sizeof(struct tcpiphdr) 120 * For IPv6 the MSS is IPV6_MMTU - sizeof(struct ip6_hdr) - sizeof(struct tcphdr) 121 * 122 * We use explicit numerical definition here to avoid header pollution. 123 */ 124#define TCP_MSS 536 125#define TCP6_MSS 1220 126 127/* 128 * Limit the lowest MSS we accept for path MTU discovery and the TCP SYN MSS 129 * option. Allowing low values of MSS can consume significant resources and 130 * be used to mount a resource exhaustion attack. 131 * Connections requesting lower MSS values will be rounded up to this value 132 * and the IP_DF flag will be cleared to allow fragmentation along the path. 133 * 134 * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments. Setting 135 * it to "0" disables the minmss check. 136 * 137 * The default value is fine for TCP across the Internet's smallest official 138 * link MTU (256 bytes for AX.25 packet radio). However, a connection is very 139 * unlikely to come across such low MTU interfaces these days (anno domini 2003). 140 */ 141#define TCP_MINMSS 216 142 143#define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 144#define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */ 145 146#define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 147 148#define TCP_MAXBURST 4 /* maximum segments in a burst */ 149 150#define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */ 151#define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr)) 152 /* max space left for options */ 153#endif /* __BSD_VISIBLE */ 154 155/* 156 * User-settable options (used with setsockopt). These are discrete 157 * values and are not masked together. Some values appear to be 158 * bitmasks for historical reasons. 159 */ 160#define TCP_NODELAY 1 /* don't delay send to coalesce packets */ 161#if __BSD_VISIBLE 162#define TCP_MAXSEG 2 /* set maximum segment size */ 163#define TCP_NOPUSH 4 /* don't push last block of write */ 164#define TCP_NOOPT 8 /* don't use TCP options */ 165#define TCP_MD5SIG 16 /* use MD5 digests (RFC2385) */ 166#define TCP_INFO 32 /* retrieve tcp_info structure */ 167#define TCP_CONGESTION 64 /* get/set congestion control algorithm */ 168#define TCP_CCALGOOPT 65 /* get/set cc algorithm specific options */ 169#define TCP_KEEPINIT 128 /* N, time to establish connection */ 170#define TCP_KEEPIDLE 256 /* L,N,X start keeplives after this period */ 171#define TCP_KEEPINTVL 512 /* L,N interval between keepalives */ 172#define TCP_KEEPCNT 1024 /* L,N number of keepalives before close */ 173#define TCP_FASTOPEN 1025 /* enable TFO / was created via TFO */ 174#define TCP_PCAP_OUT 2048 /* number of output packets to keep */ 175#define TCP_PCAP_IN 4096 /* number of input packets to keep */ 176#define TCP_FUNCTION_BLK 8192 /* Set the tcp function pointers to the specified stack */ 177/* Start of reserved space for third-party user-settable options. */ 178#define TCP_VENDOR SO_VENDOR 179 180#define TCP_CA_NAME_MAX 16 /* max congestion control name length */ 181 182#define TCPI_OPT_TIMESTAMPS 0x01 183#define TCPI_OPT_SACK 0x02 184#define TCPI_OPT_WSCALE 0x04 185#define TCPI_OPT_ECN 0x08 186#define TCPI_OPT_TOE 0x10 187 188/* 189 * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits 190 * the caller to query certain information about the state of a TCP 191 * connection. We provide an overlapping set of fields with the Linux 192 * implementation, but since this is a fixed size structure, room has been 193 * left for growth. In order to maximize potential future compatibility with 194 * the Linux API, the same variable names and order have been adopted, and 195 * padding left to make room for omitted fields in case they are added later. 196 * 197 * XXX: This is currently an unstable ABI/API, in that it is expected to 198 * change. 199 */ 200struct tcp_info { 201 u_int8_t tcpi_state; /* TCP FSM state. */ 202 u_int8_t __tcpi_ca_state; 203 u_int8_t __tcpi_retransmits; 204 u_int8_t __tcpi_probes; 205 u_int8_t __tcpi_backoff; 206 u_int8_t tcpi_options; /* Options enabled on conn. */ 207 u_int8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */ 208 tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */ 209 210 u_int32_t tcpi_rto; /* Retransmission timeout (usec). */ 211 u_int32_t __tcpi_ato; 212 u_int32_t tcpi_snd_mss; /* Max segment size for send. */ 213 u_int32_t tcpi_rcv_mss; /* Max segment size for receive. */ 214 215 u_int32_t __tcpi_unacked; 216 u_int32_t __tcpi_sacked; 217 u_int32_t __tcpi_lost; 218 u_int32_t __tcpi_retrans; 219 u_int32_t __tcpi_fackets; 220 221 /* Times; measurements in usecs. */ 222 u_int32_t __tcpi_last_data_sent; 223 u_int32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */ 224 u_int32_t tcpi_last_data_recv; /* Time since last recv data. */ 225 u_int32_t __tcpi_last_ack_recv; 226 227 /* Metrics; variable units. */ 228 u_int32_t __tcpi_pmtu; 229 u_int32_t __tcpi_rcv_ssthresh; 230 u_int32_t tcpi_rtt; /* Smoothed RTT in usecs. */ 231 u_int32_t tcpi_rttvar; /* RTT variance in usecs. */ 232 u_int32_t tcpi_snd_ssthresh; /* Slow start threshold. */ 233 u_int32_t tcpi_snd_cwnd; /* Send congestion window. */ 234 u_int32_t __tcpi_advmss; 235 u_int32_t __tcpi_reordering; 236 237 u_int32_t __tcpi_rcv_rtt; 238 u_int32_t tcpi_rcv_space; /* Advertised recv window. */ 239 240 /* FreeBSD extensions to tcp_info. */ 241 u_int32_t tcpi_snd_wnd; /* Advertised send window. */ 242 u_int32_t tcpi_snd_bwnd; /* No longer used. */ 243 u_int32_t tcpi_snd_nxt; /* Next egress seqno */ 244 u_int32_t tcpi_rcv_nxt; /* Next ingress seqno */ 245 u_int32_t tcpi_toe_tid; /* HWTID for TOE endpoints */ 246 u_int32_t tcpi_snd_rexmitpack; /* Retransmitted packets */ 247 u_int32_t tcpi_rcv_ooopack; /* Out-of-order packets */ 248 u_int32_t tcpi_snd_zerowin; /* Zero-sized windows sent */ 249 250 /* Padding to grow without breaking ABI. */ 251 u_int32_t __tcpi_pad[26]; /* Padding. */ 252}; 253#endif 254#define TCP_FUNCTION_NAME_LEN_MAX 32 255 256struct tcp_function_set { 257 char function_set_name[TCP_FUNCTION_NAME_LEN_MAX]; 258 uint32_t pcbcnt; 259}; 260 261#endif /* !_NETINET_TCP_H_ */ 262