include/uapi/linux/tcp.h

   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
 126 struct tcp_repair_opt {
 127         __u32   opt_code;
 128         __u32   opt_val;
 129 };
 130
 131 struct tcp_repair_window {
 132         __u32   snd_wl1;
 133         __u32   snd_wnd;
 134         __u32   max_window;
 135
 136         __u32   rcv_wnd;
 137         __u32   rcv_wup;
 138 };
 139
 140 enum {
 141         TCP_NO_QUEUE,
 142         TCP_RECV_QUEUE,
 143         TCP_SEND_QUEUE,
 144         TCP_QUEUES_NR,
 145 };
 146
 147 /* for TCP_INFO socket option */
 148 #define TCPI_OPT_TIMESTAMPS     1
 149 #define TCPI_OPT_SACK           2
 150 #define TCPI_OPT_WSCALE         4
 151 #define TCPI_OPT_ECN            8 /* ECN was negociated at TCP session init */
 152 #define TCPI_OPT_ECN_SEEN       16 /* we received at least one packet with ECT */
 153 #define TCPI_OPT_SYN_DATA       32 /* SYN-ACK acked data in SYN sent or rcvd */
 154
 155 enum tcp_ca_state {
 156         TCP_CA_Open = 0,
 157 #define TCPF_CA_Open    (1<<TCP_CA_Open)
 158         TCP_CA_Disorder = 1,
 159 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
 160         TCP_CA_CWR = 2,
 161 #define TCPF_CA_CWR     (1<<TCP_CA_CWR)
 162         TCP_CA_Recovery = 3,
 163 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
 164         TCP_CA_Loss = 4
 165 #define TCPF_CA_Loss    (1<<TCP_CA_Loss)
 166 };
 167
 168 struct tcp_info {
 169         __u8    tcpi_state;
 170         __u8    tcpi_ca_state;
 171         __u8    tcpi_retransmits;
 172         __u8    tcpi_probes;
 173         __u8    tcpi_backoff;
 174         __u8    tcpi_options;
 175         __u8    tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
 176         __u8    tcpi_delivery_rate_app_limited:1;
 177
 178         __u32   tcpi_rto;
 179         __u32   tcpi_ato;
 180         __u32   tcpi_snd_mss;
 181         __u32   tcpi_rcv_mss;
 182
 183         __u32   tcpi_unacked;
 184         __u32   tcpi_sacked;
 185         __u32   tcpi_lost;
 186         __u32   tcpi_retrans;
 187         __u32   tcpi_fackets;
 188
 189         /* Times. */
 190         __u32   tcpi_last_data_sent;
 191         __u32   tcpi_last_ack_sent;     /* Not remembered, sorry. */
 192         __u32   tcpi_last_data_recv;
 193         __u32   tcpi_last_ack_recv;
 194
 195         /* Metrics. */
 196         __u32   tcpi_pmtu;
 197         __u32   tcpi_rcv_ssthresh;
 198         __u32   tcpi_rtt;
 199         __u32   tcpi_rttvar;
 200         __u32   tcpi_snd_ssthresh;
 201         __u32   tcpi_snd_cwnd;
 202         __u32   tcpi_advmss;
 203         __u32   tcpi_reordering;
 204
 205         __u32   tcpi_rcv_rtt;
 206         __u32   tcpi_rcv_space;
 207
 208         __u32   tcpi_total_retrans;
 209
 210         __u64   tcpi_pacing_rate;
 211         __u64   tcpi_max_pacing_rate;
 212         __u64   tcpi_bytes_acked;    /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
 213         __u64   tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
 214         __u32   tcpi_segs_out;       /* RFC4898 tcpEStatsPerfSegsOut */
 215         __u32   tcpi_segs_in;        /* RFC4898 tcpEStatsPerfSegsIn */
 216
 217         __u32   tcpi_notsent_bytes;
 218         __u32   tcpi_min_rtt;
 219         __u32   tcpi_data_segs_in;      /* RFC4898 tcpEStatsDataSegsIn */
 220         __u32   tcpi_data_segs_out;     /* RFC4898 tcpEStatsDataSegsOut */
 221
 222         __u64   tcpi_delivery_rate;
 223
 224         __u64   tcpi_busy_time;      /* Time (usec) busy sending data */
 225         __u64   tcpi_rwnd_limited;   /* Time (usec) limited by receive window */
 226         __u64   tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
 227 };
 228
 229 /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
 230 enum {
 231         TCP_NLA_PAD,
 232         TCP_NLA_BUSY,           /* Time (usec) busy sending data */
 233         TCP_NLA_RWND_LIMITED,   /* Time (usec) limited by receive window */
 234         TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */
 235         TCP_NLA_DATA_SEGS_OUT,  /* Data pkts sent including retransmission */
 236         TCP_NLA_TOTAL_RETRANS,  /* Data pkts retransmitted */
 237         TCP_NLA_PACING_RATE,    /* Pacing rate in bytes per second */
 238         TCP_NLA_DELIVERY_RATE,  /* Delivery rate in bytes per second */
 239         TCP_NLA_SND_CWND,       /* Sending congestion window */
 240         TCP_NLA_REORDERING,     /* Reordering metric */
 241         TCP_NLA_MIN_RTT,        /* minimum RTT */
 242         TCP_NLA_RECUR_RETRANS,  /* Recurring retransmits for the current pkt */
 243         TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */
 244
 245 };
 246
 247 /* for TCP_MD5SIG socket option */
 248 #define TCP_MD5SIG_MAXKEYLEN    80
 249
 250 /* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
 251 #define TCP_MD5SIG_FLAG_PREFIX          1       /* address prefix length */
 252
 253 struct tcp_md5sig {
 254         struct __kernel_sockaddr_storage tcpm_addr;     /* address associated */
 255         __u8    tcpm_flags;                             /* extension flags */
 256         __u8    tcpm_prefixlen;                         /* address prefix */
 257         __u16   tcpm_keylen;                            /* key length */
 258         __u32   __tcpm_pad;                             /* zero */
 259         __u8    tcpm_key[TCP_MD5SIG_MAXKEYLEN];         /* key (binary) */
 260 };
 261
 262 /* INET_DIAG_MD5SIG */
 263 struct tcp_diag_md5sig {
 264         __u8    tcpm_family;
 265         __u8    tcpm_prefixlen;
 266         __u16   tcpm_keylen;
 267         __be32  tcpm_addr[4];
 268         __u8    tcpm_key[TCP_MD5SIG_MAXKEYLEN];
 269 };
 270
 271 #endif /* _UAPI_LINUX_TCP_H */