1 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * Definitions for the TCP protocol. 8 * 9 * Version: @(#)tcp.h 1.0.2 04/28/93 10 * 11 * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License 15 * as published by the Free Software Foundation; either version 16 * 2 of the License, or (at your option) any later version. 17 */ 18 #ifndef _UAPI_LINUX_TCP_H 19 #define _UAPI_LINUX_TCP_H 20 21 #include <linux/types.h> 22 #include <asm/byteorder.h> 23 #include <linux/socket.h> 24 25 struct tcphdr { 26 __be16 source; 27 __be16 dest; 28 __be32 seq; 29 __be32 ack_seq; 30 #if defined(__LITTLE_ENDIAN_BITFIELD) 31 __u16 res1:4, 32 doff:4, 33 fin:1, 34 syn:1, 35 rst:1, 36 psh:1, 37 ack:1, 38 urg:1, 39 ece:1, 40 cwr:1; 41 #elif defined(__BIG_ENDIAN_BITFIELD) 42 __u16 doff:4, 43 res1:4, 44 cwr:1, 45 ece:1, 46 urg:1, 47 ack:1, 48 psh:1, 49 rst:1, 50 syn:1, 51 fin:1; 52 #else 53 #error "Adjust your <asm/byteorder.h> defines" 54 #endif 55 __be16 window; 56 __sum16 check; 57 __be16 urg_ptr; 58 }; 59 60 /* 61 * The union cast uses a gcc extension to avoid aliasing problems 62 * (union is compatible to any of its members) 63 * This means this part of the code is -fstrict-aliasing safe now. 64 */ 65 union tcp_word_hdr { 66 struct tcphdr hdr; 67 __be32 words[5]; 68 }; 69 70 #define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3]) 71 72 enum { 73 TCP_FLAG_CWR = __constant_cpu_to_be32(0x00800000), 74 TCP_FLAG_ECE = __constant_cpu_to_be32(0x00400000), 75 TCP_FLAG_URG = __constant_cpu_to_be32(0x00200000), 76 TCP_FLAG_ACK = __constant_cpu_to_be32(0x00100000), 77 TCP_FLAG_PSH = __constant_cpu_to_be32(0x00080000), 78 TCP_FLAG_RST = __constant_cpu_to_be32(0x00040000), 79 TCP_FLAG_SYN = __constant_cpu_to_be32(0x00020000), 80 TCP_FLAG_FIN = __constant_cpu_to_be32(0x00010000), 81 TCP_RESERVED_BITS = __constant_cpu_to_be32(0x0F000000), 82 TCP_DATA_OFFSET = __constant_cpu_to_be32(0xF0000000) 83 }; 84 85 /* 86 * TCP general constants 87 */ 88 #define TCP_MSS_DEFAULT 536U /* IPv4 (RFC1122, RFC2581) */ 89 #define TCP_MSS_DESIRED 1220U /* IPv6 (tunneled), EDNS0 (RFC3226) */ 90 91 /* TCP socket options */ 92 #define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */ 93 #define TCP_MAXSEG 2 /* Limit MSS */ 94 #define TCP_CORK 3 /* Never send partially complete segments */ 95 #define TCP_KEEPIDLE 4 /* Start keeplives after this period */ 96 #define TCP_KEEPINTVL 5 /* Interval between keepalives */ 97 #define TCP_KEEPCNT 6 /* Number of keepalives before death */ 98 #define TCP_SYNCNT 7 /* Number of SYN retransmits */ 99 #define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */ 100 #define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */ 101 #define TCP_WINDOW_CLAMP 10 /* Bound advertised window */ 102 #define TCP_INFO 11 /* Information about this connection. */ 103 #define TCP_QUICKACK 12 /* Block/reenable quick acks */ 104 #define TCP_CONGESTION 13 /* Congestion control algorithm */ 105 #define TCP_MD5SIG 14 /* TCP MD5 Signature (RFC2385) */ 106 #define TCP_THIN_LINEAR_TIMEOUTS 16 /* Use linear timeouts for thin streams*/ 107 #define TCP_THIN_DUPACK 17 /* Fast retrans. after 1 dupack */ 108 #define TCP_USER_TIMEOUT 18 /* How long for loss retry before timeout */ 109 #define TCP_REPAIR 19 /* TCP sock is under repair right now */ 110 #define TCP_REPAIR_QUEUE 20 111 #define TCP_QUEUE_SEQ 21 112 #define TCP_REPAIR_OPTIONS 22 113 #define TCP_FASTOPEN 23 /* Enable FastOpen on listeners */ 114 #define TCP_TIMESTAMP 24 115 #define TCP_NOTSENT_LOWAT 25 /* limit number of unsent bytes in write queue */ 116 #define TCP_CC_INFO 26 /* Get Congestion Control (optional) info */ 117 #define TCP_SAVE_SYN 27 /* Record SYN headers for new connections */ 118 #define TCP_SAVED_SYN 28 /* Get SYN headers recorded for connection */ 119 #define TCP_REPAIR_WINDOW 29 /* Get/set window parameters */ 120 #define TCP_FASTOPEN_CONNECT 30 /* Attempt FastOpen with connect */ 121 #define TCP_ULP 31 /* Attach a ULP to a TCP connection */ 122 #define TCP_MD5SIG_EXT 32 /* TCP MD5 Signature with extensions */ 123 #define TCP_FASTOPEN_KEY 33 /* Set the key for Fast Open (cookie) */ 124 #define TCP_FASTOPEN_NO_COOKIE 34 /* Enable TFO without a TFO cookie */ 125 #define TCP_ZEROCOPY_RECEIVE 35 126 #define TCP_INQ 36 /* Notify bytes available to read as a cmsg on read */ 127 128 #define TCP_CM_INQ TCP_INQ 129 130 #define TCP_TX_DELAY 37 /* delay outgoing packets by XX usec */ 131 132 133 #define TCP_REPAIR_ON 1 134 #define TCP_REPAIR_OFF 0 135 #define TCP_REPAIR_OFF_NO_WP -1 /* Turn off without window probes */ 136 137 struct tcp_repair_opt { 138 __u32 opt_code; 139 __u32 opt_val; 140 }; 141 142 struct tcp_repair_window { 143 __u32 snd_wl1; 144 __u32 snd_wnd; 145 __u32 max_window; 146 147 __u32 rcv_wnd; 148 __u32 rcv_wup; 149 }; 150 151 enum { 152 TCP_NO_QUEUE, 153 TCP_RECV_QUEUE, 154 TCP_SEND_QUEUE, 155 TCP_QUEUES_NR, 156 }; 157 158 /* for TCP_INFO socket option */ 159 #define TCPI_OPT_TIMESTAMPS 1 160 #define TCPI_OPT_SACK 2 161 #define TCPI_OPT_WSCALE 4 162 #define TCPI_OPT_ECN 8 /* ECN was negociated at TCP session init */ 163 #define TCPI_OPT_ECN_SEEN 16 /* we received at least one packet with ECT */ 164 #define TCPI_OPT_SYN_DATA 32 /* SYN-ACK acked data in SYN sent or rcvd */ 165 166 /* 167 * Sender's congestion state indicating normal or abnormal situations 168 * in the last round of packets sent. The state is driven by the ACK 169 * information and timer events. 170 */ 171 enum tcp_ca_state { 172 /* 173 * Nothing bad has been observed recently. 174 * No apparent reordering, packet loss, or ECN marks. 175 */ 176 TCP_CA_Open = 0, 177 #define TCPF_CA_Open (1<<TCP_CA_Open) 178 /* 179 * The sender enters disordered state when it has received DUPACKs or 180 * SACKs in the last round of packets sent. This could be due to packet 181 * loss or reordering but needs further information to confirm packets 182 * have been lost. 183 */ 184 TCP_CA_Disorder = 1, 185 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder) 186 /* 187 * The sender enters Congestion Window Reduction (CWR) state when it 188 * has received ACKs with ECN-ECE marks, or has experienced congestion 189 * or packet discard on the sender host (e.g. qdisc). 190 */ 191 TCP_CA_CWR = 2, 192 #define TCPF_CA_CWR (1<<TCP_CA_CWR) 193 /* 194 * The sender is in fast recovery and retransmitting lost packets, 195 * typically triggered by ACK events. 196 */ 197 TCP_CA_Recovery = 3, 198 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery) 199 /* 200 * The sender is in loss recovery triggered by retransmission timeout. 201 */ 202 TCP_CA_Loss = 4 203 #define TCPF_CA_Loss (1<<TCP_CA_Loss) 204 }; 205 206 struct tcp_info { 207 __u8 tcpi_state; 208 __u8 tcpi_ca_state; 209 __u8 tcpi_retransmits; 210 __u8 tcpi_probes; 211 __u8 tcpi_backoff; 212 __u8 tcpi_options; 213 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4; 214 __u8 tcpi_delivery_rate_app_limited:1; 215 216 __u32 tcpi_rto; 217 __u32 tcpi_ato; 218 __u32 tcpi_snd_mss; 219 __u32 tcpi_rcv_mss; 220 221 __u32 tcpi_unacked; 222 __u32 tcpi_sacked; 223 __u32 tcpi_lost; 224 __u32 tcpi_retrans; 225 __u32 tcpi_fackets; 226 227 /* Times. */ 228 __u32 tcpi_last_data_sent; 229 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */ 230 __u32 tcpi_last_data_recv; 231 __u32 tcpi_last_ack_recv; 232 233 /* Metrics. */ 234 __u32 tcpi_pmtu; 235 __u32 tcpi_rcv_ssthresh; 236 __u32 tcpi_rtt; 237 __u32 tcpi_rttvar; 238 __u32 tcpi_snd_ssthresh; 239 __u32 tcpi_snd_cwnd; 240 __u32 tcpi_advmss; 241 __u32 tcpi_reordering; 242 243 __u32 tcpi_rcv_rtt; 244 __u32 tcpi_rcv_space; 245 246 __u32 tcpi_total_retrans; 247 248 __u64 tcpi_pacing_rate; 249 __u64 tcpi_max_pacing_rate; 250 __u64 tcpi_bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked */ 251 __u64 tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */ 252 __u32 tcpi_segs_out; /* RFC4898 tcpEStatsPerfSegsOut */ 253 __u32 tcpi_segs_in; /* RFC4898 tcpEStatsPerfSegsIn */ 254 255 __u32 tcpi_notsent_bytes; 256 __u32 tcpi_min_rtt; 257 __u32 tcpi_data_segs_in; /* RFC4898 tcpEStatsDataSegsIn */ 258 __u32 tcpi_data_segs_out; /* RFC4898 tcpEStatsDataSegsOut */ 259 260 __u64 tcpi_delivery_rate; 261 262 __u64 tcpi_busy_time; /* Time (usec) busy sending data */ 263 __u64 tcpi_rwnd_limited; /* Time (usec) limited by receive window */ 264 __u64 tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */ 265 266 __u32 tcpi_delivered; 267 __u32 tcpi_delivered_ce; 268 269 __u64 tcpi_bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut */ 270 __u64 tcpi_bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans */ 271 __u32 tcpi_dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups */ 272 __u32 tcpi_reord_seen; /* reordering events seen */ 273 274 __u32 tcpi_rcv_ooopack; /* Out-of-order packets received */ 275 276 __u32 tcpi_snd_wnd; /* peer's advertised receive window after 277 * scaling (bytes) 278 */ 279 }; 280 281 /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */ 282 enum { 283 TCP_NLA_PAD, 284 TCP_NLA_BUSY, /* Time (usec) busy sending data */ 285 TCP_NLA_RWND_LIMITED, /* Time (usec) limited by receive window */ 286 TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */ 287 TCP_NLA_DATA_SEGS_OUT, /* Data pkts sent including retransmission */ 288 TCP_NLA_TOTAL_RETRANS, /* Data pkts retransmitted */ 289 TCP_NLA_PACING_RATE, /* Pacing rate in bytes per second */ 290 TCP_NLA_DELIVERY_RATE, /* Delivery rate in bytes per second */ 291 TCP_NLA_SND_CWND, /* Sending congestion window */ 292 TCP_NLA_REORDERING, /* Reordering metric */ 293 TCP_NLA_MIN_RTT, /* minimum RTT */ 294 TCP_NLA_RECUR_RETRANS, /* Recurring retransmits for the current pkt */ 295 TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */ 296 TCP_NLA_SNDQ_SIZE, /* Data (bytes) pending in send queue */ 297 TCP_NLA_CA_STATE, /* ca_state of socket */ 298 TCP_NLA_SND_SSTHRESH, /* Slow start size threshold */ 299 TCP_NLA_DELIVERED, /* Data pkts delivered incl. out-of-order */ 300 TCP_NLA_DELIVERED_CE, /* Like above but only ones w/ CE marks */ 301 TCP_NLA_BYTES_SENT, /* Data bytes sent including retransmission */ 302 TCP_NLA_BYTES_RETRANS, /* Data bytes retransmitted */ 303 TCP_NLA_DSACK_DUPS, /* DSACK blocks received */ 304 TCP_NLA_REORD_SEEN, /* reordering events seen */ 305 TCP_NLA_SRTT, /* smoothed RTT in usecs */ 306 }; 307 308 /* for TCP_MD5SIG socket option */ 309 #define TCP_MD5SIG_MAXKEYLEN 80 310 311 /* tcp_md5sig extension flags for TCP_MD5SIG_EXT */ 312 #define TCP_MD5SIG_FLAG_PREFIX 1 /* address prefix length */ 313 314 struct tcp_md5sig { 315 struct __kernel_sockaddr_storage tcpm_addr; /* address associated */ 316 __u8 tcpm_flags; /* extension flags */ 317 __u8 tcpm_prefixlen; /* address prefix */ 318 __u16 tcpm_keylen; /* key length */ 319 __u32 __tcpm_pad; /* zero */ 320 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */ 321 }; 322 323 /* INET_DIAG_MD5SIG */ 324 struct tcp_diag_md5sig { 325 __u8 tcpm_family; 326 __u8 tcpm_prefixlen; 327 __u16 tcpm_keylen; 328 __be32 tcpm_addr[4]; 329 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; 330 }; 331 332 /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */ 333 334 struct tcp_zerocopy_receive { 335 __u64 address; /* in: address of mapping */ 336 __u32 length; /* in/out: number of bytes to map/mapped */ 337 __u32 recv_skip_hint; /* out: amount of bytes to skip */ 338 }; 339 #endif /* _UAPI_LINUX_TCP_H */ 340