1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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 * $FreeBSD: stable/12/sys/netinet/tcp.h 372722 2022-11-10 07:48:12Z rscheff $ 33 */ 34 35 #ifndef _NETINET_TCP_H_ 36 #define _NETINET_TCP_H_ 37 38 #include <sys/cdefs.h> 39 #include <sys/types.h> 40 41 #if __BSD_VISIBLE 42 43 typedef u_int32_t tcp_seq; 44 45 #define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */ 46 #define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */ 47 48 /* 49 * TCP header. 50 * Per RFC 793, September, 1981. 51 */ 52 struct tcphdr { 53 u_short th_sport; /* source port */ 54 u_short th_dport; /* destination port */ 55 tcp_seq th_seq; /* sequence number */ 56 tcp_seq th_ack; /* acknowledgement number */ 57 #if BYTE_ORDER == LITTLE_ENDIAN 58 u_char th_x2:4, /* (unused) */ 59 th_off:4; /* data offset */ 60 #endif 61 #if BYTE_ORDER == BIG_ENDIAN 62 u_char th_off:4, /* data offset */ 63 th_x2:4; /* (unused) */ 64 #endif 65 u_char th_flags; 66 #define TH_FIN 0x01 67 #define TH_SYN 0x02 68 #define TH_RST 0x04 69 #define TH_PUSH 0x08 70 #define TH_ACK 0x10 71 #define TH_URG 0x20 72 #define TH_ECE 0x40 73 #define TH_CWR 0x80 74 #define TH_AE 0x100 /* maps into th_x2 */ 75 #define TH_RES3 0x200 76 #define TH_RES2 0x400 77 #define TH_RES1 0x800 78 #define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG|TH_ECE|TH_CWR) 79 #define PRINT_TH_FLAGS "\20\1FIN\2SYN\3RST\4PUSH\5ACK\6URG\7ECE\10CWR\11AE" 80 81 u_short th_win; /* window */ 82 u_short th_sum; /* checksum */ 83 u_short th_urp; /* urgent pointer */ 84 }; 85 86 #define PADTCPOLEN(len) ((((len) / 4) + !!((len) % 4)) * 4) 87 88 #define TCPOPT_EOL 0 89 #define TCPOLEN_EOL 1 90 #define TCPOPT_PAD 0 /* padding after EOL */ 91 #define TCPOLEN_PAD 1 92 #define TCPOPT_NOP 1 93 #define TCPOLEN_NOP 1 94 #define TCPOPT_MAXSEG 2 95 #define TCPOLEN_MAXSEG 4 96 #define TCPOPT_WINDOW 3 97 #define TCPOLEN_WINDOW 3 98 #define TCPOPT_SACK_PERMITTED 4 99 #define TCPOLEN_SACK_PERMITTED 2 100 #define TCPOPT_SACK 5 101 #define TCPOLEN_SACKHDR 2 102 #define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ 103 #define TCPOPT_TIMESTAMP 8 104 #define TCPOLEN_TIMESTAMP 10 105 #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 106 #define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */ 107 #define TCPOLEN_SIGNATURE 18 108 #define TCPOPT_FAST_OPEN 34 109 #define TCPOLEN_FAST_OPEN_EMPTY 2 110 111 #define MAX_TCPOPTLEN 40 /* Absolute maximum TCP options len */ 112 113 /* Miscellaneous constants */ 114 #define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at receiver side */ 115 #define TCP_MAX_SACK 4 /* MAX # SACKs sent in any segment */ 116 117 118 /* 119 * The default maximum segment size (MSS) to be used for new TCP connections 120 * when path MTU discovery is not enabled. 121 * 122 * RFC879 derives the default MSS from the largest datagram size hosts are 123 * minimally required to handle directly or through IP reassembly minus the 124 * size of the IP and TCP header. With IPv6 the minimum MTU is specified 125 * in RFC2460. 126 * 127 * For IPv4 the MSS is 576 - sizeof(struct tcpiphdr) 128 * For IPv6 the MSS is IPV6_MMTU - sizeof(struct ip6_hdr) - sizeof(struct tcphdr) 129 * 130 * We use explicit numerical definition here to avoid header pollution. 131 */ 132 #define TCP_MSS 536 133 #define TCP6_MSS 1220 134 135 /* 136 * Limit the lowest MSS we accept for path MTU discovery and the TCP SYN MSS 137 * option. Allowing low values of MSS can consume significant resources and 138 * be used to mount a resource exhaustion attack. 139 * Connections requesting lower MSS values will be rounded up to this value 140 * and the IP_DF flag will be cleared to allow fragmentation along the path. 141 * 142 * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments. Setting 143 * it to "0" disables the minmss check. 144 * 145 * The default value is fine for TCP across the Internet's smallest official 146 * link MTU (256 bytes for AX.25 packet radio). However, a connection is very 147 * unlikely to come across such low MTU interfaces these days (anno domini 2003). 148 */ 149 #define TCP_MINMSS 216 150 151 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 152 #define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */ 153 154 #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 155 156 #define TCP_MAXBURST 4 /* maximum segments in a burst */ 157 158 #define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */ 159 #define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr)) 160 /* max space left for options */ 161 162 #define TCP_FASTOPEN_MIN_COOKIE_LEN 4 /* Per RFC7413 */ 163 #define TCP_FASTOPEN_MAX_COOKIE_LEN 16 /* Per RFC7413 */ 164 #define TCP_FASTOPEN_PSK_LEN 16 /* Same as TCP_FASTOPEN_KEY_LEN */ 165 #endif /* __BSD_VISIBLE */ 166 167 /* 168 * User-settable options (used with setsockopt). These are discrete 169 * values and are not masked together. Some values appear to be 170 * bitmasks for historical reasons. 171 */ 172 #define TCP_NODELAY 1 /* don't delay send to coalesce packets */ 173 #if __BSD_VISIBLE 174 #define TCP_MAXSEG 2 /* set maximum segment size */ 175 #define TCP_NOPUSH 4 /* don't push last block of write */ 176 #define TCP_NOOPT 8 /* don't use TCP options */ 177 #define TCP_MD5SIG 16 /* use MD5 digests (RFC2385) */ 178 #define TCP_INFO 32 /* retrieve tcp_info structure */ 179 #define TCP_LOG 34 /* configure event logging for connection */ 180 #define TCP_LOGBUF 35 /* retrieve event log for connection */ 181 #define TCP_LOGID 36 /* configure log ID to correlate connections */ 182 #define TCP_LOGDUMP 37 /* dump connection log events to device */ 183 #define TCP_LOGDUMPID 38 /* dump events from connections with same ID to 184 device */ 185 #define TCP_CONGESTION 64 /* get/set congestion control algorithm */ 186 #define TCP_CCALGOOPT 65 /* get/set cc algorithm specific options */ 187 #define TCP_DELACK 72 /* socket option for delayed ack */ 188 #define TCP_KEEPINIT 128 /* N, time to establish connection */ 189 #define TCP_KEEPIDLE 256 /* L,N,X start keeplives after this period */ 190 #define TCP_KEEPINTVL 512 /* L,N interval between keepalives */ 191 #define TCP_KEEPCNT 1024 /* L,N number of keepalives before close */ 192 #define TCP_FASTOPEN 1025 /* enable TFO / was created via TFO */ 193 #define TCP_PCAP_OUT 2048 /* number of output packets to keep */ 194 #define TCP_PCAP_IN 4096 /* number of input packets to keep */ 195 #define TCP_FUNCTION_BLK 8192 /* Set the tcp function pointers to the specified stack */ 196 /* Options for Rack and BBR */ 197 #define TCP_RACK_PROP 1051 /* RACK proportional rate reduction (bool) */ 198 #define TCP_RACK_TLP_REDUCE 1052 /* RACK TLP cwnd reduction (bool) */ 199 #define TCP_RACK_PACE_REDUCE 1053 /* RACK Pacing reduction factor (divisor) */ 200 #define TCP_RACK_PACE_MAX_SEG 1054 /* Max segments in a pace */ 201 #define TCP_RACK_PACE_ALWAYS 1055 /* Use the always pace method */ 202 #define TCP_RACK_PROP_RATE 1056 /* The proportional reduction rate */ 203 #define TCP_RACK_PRR_SENDALOT 1057 /* Allow PRR to send more than one seg */ 204 #define TCP_RACK_MIN_TO 1058 /* Minimum time between rack t-o's in ms */ 205 #define TCP_RACK_EARLY_RECOV 1059 /* Should recovery happen early (bool) */ 206 #define TCP_RACK_EARLY_SEG 1060 /* If early recovery max segments */ 207 #define TCP_RACK_REORD_THRESH 1061 /* RACK reorder threshold (shift amount) */ 208 #define TCP_RACK_REORD_FADE 1062 /* Does reordering fade after ms time */ 209 #define TCP_RACK_TLP_THRESH 1063 /* RACK TLP theshold i.e. srtt+(srtt/N) */ 210 #define TCP_RACK_PKT_DELAY 1064 /* RACK added ms i.e. rack-rtt + reord + N */ 211 #define TCP_RACK_TLP_INC_VAR 1065 /* Does TLP include rtt variance in t-o */ 212 #define TCP_BBR_IWINTSO 1067 /* Initial TSO window for BBRs first sends */ 213 #define TCP_BBR_RECFORCE 1068 /* Enter recovery force out a segment disregard pacer no longer valid */ 214 #define TCP_BBR_STARTUP_PG 1069 /* Startup pacing gain */ 215 #define TCP_BBR_DRAIN_PG 1070 /* Drain pacing gain */ 216 #define TCP_BBR_RWND_IS_APP 1071 /* Rwnd limited is considered app limited */ 217 #define TCP_BBR_PROBE_RTT_INT 1072 /* How long in useconds between probe-rtt */ 218 #define TCP_BBR_ONE_RETRAN 1073 /* Is only one segment allowed out during retran */ 219 #define TCP_BBR_STARTUP_LOSS_EXIT 1074 /* Do we exit a loss during startup if not 20% incr */ 220 #define TCP_BBR_USE_LOWGAIN 1075 /* lower the gain in PROBE_BW enable */ 221 #define TCP_BBR_LOWGAIN_THRESH 1076 /* Unused after 2.3 morphs to TSLIMITS >= 2.3 */ 222 #define TCP_BBR_TSLIMITS 1076 /* Do we use experimental Timestamp limiting for our algo */ 223 #define TCP_BBR_LOWGAIN_HALF 1077 /* Unused after 2.3 */ 224 #define TCP_BBR_PACE_OH 1077 /* Reused in 4.2 for pacing overhead setting */ 225 #define TCP_BBR_LOWGAIN_FD 1078 /* Unused after 2.3 */ 226 #define TCP_BBR_HOLD_TARGET 1078 /* For 4.3 on */ 227 #define TCP_BBR_USEDEL_RATE 1079 /* Enable use of delivery rate for loss recovery */ 228 #define TCP_BBR_MIN_RTO 1080 /* Min RTO in milliseconds */ 229 #define TCP_BBR_MAX_RTO 1081 /* Max RTO in milliseconds */ 230 #define TCP_BBR_REC_OVER_HPTS 1082 /* Recovery override htps settings 0/1/3 */ 231 #define TCP_BBR_UNLIMITED 1083 /* Not used before 2.3 and morphs to algorithm >= 2.3 */ 232 #define TCP_BBR_ALGORITHM 1083 /* What measurement algo does BBR use netflix=0, google=1 */ 233 #define TCP_BBR_DRAIN_INC_EXTRA 1084 /* Does the 3/4 drain target include the extra gain */ 234 #define TCP_BBR_STARTUP_EXIT_EPOCH 1085 /* what epoch gets us out of startup */ 235 #define TCP_BBR_PACE_PER_SEC 1086 236 #define TCP_BBR_PACE_DEL_TAR 1087 237 #define TCP_BBR_PACE_SEG_MAX 1088 238 #define TCP_BBR_PACE_SEG_MIN 1089 239 #define TCP_BBR_PACE_CROSS 1090 240 #define TCP_RACK_IDLE_REDUCE_HIGH 1092 /* Reduce the highest cwnd seen to IW on idle */ 241 #define TCP_RACK_MIN_PACE 1093 /* Do we enforce rack min pace time */ 242 #define TCP_RACK_MIN_PACE_SEG 1094 /* If so what is the seg threshould */ 243 #define TCP_RACK_GP_INCREASE 1094 /* After 4.1 its the GP increase */ 244 #define TCP_RACK_TLP_USE 1095 245 #define TCP_BBR_ACK_COMP_ALG 1096 /* Not used */ 246 #define TCP_BBR_TMR_PACE_OH 1096 /* Recycled in 4.2 */ 247 #define TCP_BBR_EXTRA_GAIN 1097 248 #define TCP_BBR_RACK_RTT_USE 1098 /* what RTT should we use 0, 1, or 2? */ 249 #define TCP_BBR_RETRAN_WTSO 1099 250 #define TCP_DATA_AFTER_CLOSE 1100 251 #define TCP_BBR_PROBE_RTT_GAIN 1101 252 #define TCP_BBR_PROBE_RTT_LEN 1102 253 #define TCP_BBR_SEND_IWND_IN_TSO 1103 /* Do we burst out whole iwin size chunks at start? */ 254 #define TCP_BBR_USE_RACK_CHEAT 1104 /* Do we use the rack cheat for pacing rxt's */ 255 #define TCP_BBR_HDWR_PACE 1105 /* Enable/disable hardware pacing */ 256 #define TCP_BBR_UTTER_MAX_TSO 1106 /* Do we enforce an utter max TSO size */ 257 #define TCP_BBR_EXTRA_STATE 1107 /* Special exit-persist catch up */ 258 #define TCP_BBR_FLOOR_MIN_TSO 1108 /* The min tso size */ 259 #define TCP_BBR_MIN_TOPACEOUT 1109 /* Do we suspend pacing until */ 260 #define TCP_BBR_TSTMP_RAISES 1110 /* Can a timestamp measurement raise the b/w */ 261 #define TCP_BBR_POLICER_DETECT 1111 /* Turn on/off google mode policer detection */ 262 263 264 /* Start of reserved space for third-party user-settable options. */ 265 #define TCP_VENDOR SO_VENDOR 266 267 #define TCP_CA_NAME_MAX 16 /* max congestion control name length */ 268 269 #define TCPI_OPT_TIMESTAMPS 0x01 270 #define TCPI_OPT_SACK 0x02 271 #define TCPI_OPT_WSCALE 0x04 272 #define TCPI_OPT_ECN 0x08 273 #define TCPI_OPT_TOE 0x10 274 275 /* Maximum length of log ID. */ 276 #define TCP_LOG_ID_LEN 64 277 278 /* 279 * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits 280 * the caller to query certain information about the state of a TCP 281 * connection. We provide an overlapping set of fields with the Linux 282 * implementation, but since this is a fixed size structure, room has been 283 * left for growth. In order to maximize potential future compatibility with 284 * the Linux API, the same variable names and order have been adopted, and 285 * padding left to make room for omitted fields in case they are added later. 286 * 287 * XXX: This is currently an unstable ABI/API, in that it is expected to 288 * change. 289 */ 290 struct tcp_info { 291 u_int8_t tcpi_state; /* TCP FSM state. */ 292 u_int8_t __tcpi_ca_state; 293 u_int8_t __tcpi_retransmits; 294 u_int8_t __tcpi_probes; 295 u_int8_t __tcpi_backoff; 296 u_int8_t tcpi_options; /* Options enabled on conn. */ 297 u_int8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */ 298 tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */ 299 300 u_int32_t tcpi_rto; /* Retransmission timeout (usec). */ 301 u_int32_t __tcpi_ato; 302 u_int32_t tcpi_snd_mss; /* Max segment size for send. */ 303 u_int32_t tcpi_rcv_mss; /* Max segment size for receive. */ 304 305 u_int32_t __tcpi_unacked; 306 u_int32_t __tcpi_sacked; 307 u_int32_t __tcpi_lost; 308 u_int32_t __tcpi_retrans; 309 u_int32_t __tcpi_fackets; 310 311 /* Times; measurements in usecs. */ 312 u_int32_t __tcpi_last_data_sent; 313 u_int32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */ 314 u_int32_t tcpi_last_data_recv; /* Time since last recv data. */ 315 u_int32_t __tcpi_last_ack_recv; 316 317 /* Metrics; variable units. */ 318 u_int32_t __tcpi_pmtu; 319 u_int32_t __tcpi_rcv_ssthresh; 320 u_int32_t tcpi_rtt; /* Smoothed RTT in usecs. */ 321 u_int32_t tcpi_rttvar; /* RTT variance in usecs. */ 322 u_int32_t tcpi_snd_ssthresh; /* Slow start threshold. */ 323 u_int32_t tcpi_snd_cwnd; /* Send congestion window. */ 324 u_int32_t __tcpi_advmss; 325 u_int32_t __tcpi_reordering; 326 327 u_int32_t __tcpi_rcv_rtt; 328 u_int32_t tcpi_rcv_space; /* Advertised recv window. */ 329 330 /* FreeBSD extensions to tcp_info. */ 331 u_int32_t tcpi_snd_wnd; /* Advertised send window. */ 332 u_int32_t tcpi_snd_bwnd; /* No longer used. */ 333 u_int32_t tcpi_snd_nxt; /* Next egress seqno */ 334 u_int32_t tcpi_rcv_nxt; /* Next ingress seqno */ 335 u_int32_t tcpi_toe_tid; /* HWTID for TOE endpoints */ 336 u_int32_t tcpi_snd_rexmitpack; /* Retransmitted packets */ 337 u_int32_t tcpi_rcv_ooopack; /* Out-of-order packets */ 338 u_int32_t tcpi_snd_zerowin; /* Zero-sized windows sent */ 339 340 /* Padding to grow without breaking ABI. */ 341 u_int32_t __tcpi_pad[26]; /* Padding. */ 342 }; 343 344 /* 345 * If this structure is provided when setting the TCP_FASTOPEN socket 346 * option, and the enable member is non-zero, a subsequent connect will use 347 * pre-shared key (PSK) mode using the provided key. 348 */ 349 struct tcp_fastopen { 350 int enable; 351 uint8_t psk[TCP_FASTOPEN_PSK_LEN]; 352 }; 353 #endif 354 #define TCP_FUNCTION_NAME_LEN_MAX 32 355 356 struct tcp_function_set { 357 char function_set_name[TCP_FUNCTION_NAME_LEN_MAX]; 358 uint32_t pcbcnt; 359 }; 360 361 #endif /* !_NETINET_TCP_H_ */ 362