include/linux/tcp.h

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Definitions for the TCP protocol.
   7  *
   8  * Version:     @(#)tcp.h       1.0.2   04/28/93
   9  *
  10  * Author:      Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  11  *
  12  *              This program is free software; you can redistribute it and/or
  13  *              modify it under the terms of the GNU General Public License
  14  *              as published by the Free Software Foundation; either version
  15  *              2 of the License, or (at your option) any later version.
  16  */
  17 #ifndef _LINUX_TCP_H
  18 #define _LINUX_TCP_H
  19
  20 #include <linux/types.h>
  21 #include <asm/byteorder.h>
  22
  23 struct tcphdr {
  24         __u16   source;
  25         __u16   dest;
  26         __u32   seq;
  27         __u32   ack_seq;
  28 #if defined(__LITTLE_ENDIAN_BITFIELD)
  29         __u16   res1:4,
  30                 doff:4,
  31                 fin:1,
  32                 syn:1,
  33                 rst:1,
  34                 psh:1,
  35                 ack:1,
  36                 urg:1,
  37                 ece:1,
  38                 cwr:1;
  39 #elif defined(__BIG_ENDIAN_BITFIELD)
  40         __u16   doff:4,
  41                 res1:4,
  42                 cwr:1,
  43                 ece:1,
  44                 urg:1,
  45                 ack:1,
  46                 psh:1,
  47                 rst:1,
  48                 syn:1,
  49                 fin:1;
  50 #else
  51 #error  "Adjust your <asm/byteorder.h> defines"
  52 #endif
  53         __u16   window;
  54         __u16   check;
  55         __u16   urg_ptr;
  56 };
  57
  58 #define TCP_ACTION_FIN  (1 << 7)
  59
  60 enum {
  61   TCPF_ESTABLISHED = (1 << 1),
  62   TCPF_SYN_SENT  = (1 << 2),
  63   TCPF_SYN_RECV  = (1 << 3),
  64   TCPF_FIN_WAIT1 = (1 << 4),
  65   TCPF_FIN_WAIT2 = (1 << 5),
  66   TCPF_TIME_WAIT = (1 << 6),
  67   TCPF_CLOSE     = (1 << 7),
  68   TCPF_CLOSE_WAIT = (1 << 8),
  69   TCPF_LAST_ACK  = (1 << 9),
  70   TCPF_LISTEN    = (1 << 10),
  71   TCPF_CLOSING   = (1 << 11)
  72 };
  73
  74 /*
  75  *      The union cast uses a gcc extension to avoid aliasing problems
  76  *  (union is compatible to any of its members)
  77  *  This means this part of the code is -fstrict-aliasing safe now.
  78  */
  79 union tcp_word_hdr {
  80         struct tcphdr hdr;
  81         __u32             words[5];
  82 };
  83
  84 #define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])
  85
  86 enum {
  87         TCP_FLAG_CWR = __constant_htonl(0x00800000),
  88         TCP_FLAG_ECE = __constant_htonl(0x00400000),
  89         TCP_FLAG_URG = __constant_htonl(0x00200000),
  90         TCP_FLAG_ACK = __constant_htonl(0x00100000),
  91         TCP_FLAG_PSH = __constant_htonl(0x00080000),
  92         TCP_FLAG_RST = __constant_htonl(0x00040000),
  93         TCP_FLAG_SYN = __constant_htonl(0x00020000),
  94         TCP_FLAG_FIN = __constant_htonl(0x00010000),
  95         TCP_RESERVED_BITS = __constant_htonl(0x0F000000),
  96         TCP_DATA_OFFSET = __constant_htonl(0xF0000000)
  97 };
  98
  99 /* TCP socket options */
 100 #define TCP_NODELAY             1       /* Turn off Nagle's algorithm. */
 101 #define TCP_MAXSEG              2       /* Limit MSS */
 102 #define TCP_CORK                3       /* Never send partially complete segments */
 103 #define TCP_KEEPIDLE            4       /* Start keeplives after this period */
 104 #define TCP_KEEPINTVL           5       /* Interval between keepalives */
 105 #define TCP_KEEPCNT             6       /* Number of keepalives before death */
 106 #define TCP_SYNCNT              7       /* Number of SYN retransmits */
 107 #define TCP_LINGER2             8       /* Life time of orphaned FIN-WAIT-2 state */
 108 #define TCP_DEFER_ACCEPT        9       /* Wake up listener only when data arrive */
 109 #define TCP_WINDOW_CLAMP        10      /* Bound advertised window */
 110 #define TCP_INFO                11      /* Information about this connection. */
 111 #define TCP_QUICKACK            12      /* Block/reenable quick acks */
 112 #define TCP_CONGESTION          13      /* Congestion control algorithm */
 113
 114 #define TCPI_OPT_TIMESTAMPS     1
 115 #define TCPI_OPT_SACK           2
 116 #define TCPI_OPT_WSCALE         4
 117 #define TCPI_OPT_ECN            8
 118
 119 enum tcp_ca_state
 120 {
 121         TCP_CA_Open = 0,
 122 #define TCPF_CA_Open    (1<<TCP_CA_Open)
 123         TCP_CA_Disorder = 1,
 124 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
 125         TCP_CA_CWR = 2,
 126 #define TCPF_CA_CWR     (1<<TCP_CA_CWR)
 127         TCP_CA_Recovery = 3,
 128 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
 129         TCP_CA_Loss = 4
 130 #define TCPF_CA_Loss    (1<<TCP_CA_Loss)
 131 };
 132
 133 struct tcp_info
 134 {
 135         __u8    tcpi_state;
 136         __u8    tcpi_ca_state;
 137         __u8    tcpi_retransmits;
 138         __u8    tcpi_probes;
 139         __u8    tcpi_backoff;
 140         __u8    tcpi_options;
 141         __u8    tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
 142
 143         __u32   tcpi_rto;
 144         __u32   tcpi_ato;
 145         __u32   tcpi_snd_mss;
 146         __u32   tcpi_rcv_mss;
 147
 148         __u32   tcpi_unacked;
 149         __u32   tcpi_sacked;
 150         __u32   tcpi_lost;
 151         __u32   tcpi_retrans;
 152         __u32   tcpi_fackets;
 153
 154         /* Times. */
 155         __u32   tcpi_last_data_sent;
 156         __u32   tcpi_last_ack_sent;     /* Not remembered, sorry. */
 157         __u32   tcpi_last_data_recv;
 158         __u32   tcpi_last_ack_recv;
 159
 160         /* Metrics. */
 161         __u32   tcpi_pmtu;
 162         __u32   tcpi_rcv_ssthresh;
 163         __u32   tcpi_rtt;
 164         __u32   tcpi_rttvar;
 165         __u32   tcpi_snd_ssthresh;
 166         __u32   tcpi_snd_cwnd;
 167         __u32   tcpi_advmss;
 168         __u32   tcpi_reordering;
 169
 170         __u32   tcpi_rcv_rtt;
 171         __u32   tcpi_rcv_space;
 172
 173         __u32   tcpi_total_retrans;
 174 };
 175
 176 #ifdef __KERNEL__
 177
 178 #include <linux/config.h>
 179 #include <linux/skbuff.h>
 180 #include <net/sock.h>
 181 #include <net/inet_connection_sock.h>
 182 #include <net/inet_timewait_sock.h>
 183
 184 /* This defines a selective acknowledgement block. */
 185 struct tcp_sack_block {
 186         __u32   start_seq;
 187         __u32   end_seq;
 188 };
 189
 190 struct tcp_options_received {
 191 /*      PAWS/RTTM data  */
 192         long    ts_recent_stamp;/* Time we stored ts_recent (for aging) */
 193         __u32   ts_recent;      /* Time stamp to echo next              */
 194         __u32   rcv_tsval;      /* Time stamp value                     */
 195         __u32   rcv_tsecr;      /* Time stamp echo reply                */
 196         __u16   saw_tstamp : 1, /* Saw TIMESTAMP on last packet         */
 197                 tstamp_ok : 1,  /* TIMESTAMP seen on SYN packet         */
 198                 dsack : 1,      /* D-SACK is scheduled                  */
 199                 wscale_ok : 1,  /* Wscale seen on SYN packet            */
 200                 sack_ok : 4,    /* SACK seen on SYN packet              */
 201                 snd_wscale : 4, /* Window scaling received from sender  */
 202                 rcv_wscale : 4; /* Window scaling to send to receiver   */
 203 /*      SACKs data      */
 204         __u8    eff_sacks;      /* Size of SACK array to send with next packet */
 205         __u8    num_sacks;      /* Number of SACK blocks                */
 206         __u16   user_mss;       /* mss requested by user in ioctl */
 207         __u16   mss_clamp;      /* Maximal mss, negotiated at connection setup */
 208 };
 209
 210 struct tcp_request_sock {
 211         struct inet_request_sock req;
 212         __u32                    rcv_isn;
 213         __u32                    snt_isn;
 214 };
 215
 216 static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
 217 {
 218         return (struct tcp_request_sock *)req;
 219 }
 220
 221 struct tcp_sock {
 222         /* inet_connection_sock has to be the first member of tcp_sock */
 223         struct inet_connection_sock     inet_conn;
 224         int     tcp_header_len; /* Bytes of tcp header to send          */
 225
 226 /*
 227  *      Header prediction flags
 228  *      0x5?10 << 16 + snd_wnd in net byte order
 229  */
 230         __u32   pred_flags;
 231
 232 /*
 233  *      RFC793 variables by their proper names. This means you can
 234  *      read the code and the spec side by side (and laugh ...)
 235  *      See RFC793 and RFC1122. The RFC writes these in capitals.
 236  */
 237         __u32   rcv_nxt;        /* What we want to receive next         */
 238         __u32   snd_nxt;        /* Next sequence we send                */
 239
 240         __u32   snd_una;        /* First byte we want an ack for        */
 241         __u32   snd_sml;        /* Last byte of the most recently transmitted small packet */
 242         __u32   rcv_tstamp;     /* timestamp of last received ACK (for keepalives) */
 243         __u32   lsndtime;       /* timestamp of last sent data packet (for restart window) */
 244
 245         /* Data for direct copy to user */
 246         struct {
 247                 struct sk_buff_head     prequeue;
 248                 struct task_struct      *task;
 249                 struct iovec            *iov;
 250                 int                     memory;
 251                 int                     len;
 252         } ucopy;
 253
 254         __u32   snd_wl1;        /* Sequence for window update           */
 255         __u32   snd_wnd;        /* The window we expect to receive      */
 256         __u32   max_window;     /* Maximal window ever seen from peer   */
 257         __u32   pmtu_cookie;    /* Last pmtu seen by socket             */
 258         __u32   mss_cache;      /* Cached effective mss, not including SACKS */
 259         __u16   xmit_size_goal; /* Goal for segmenting output packets   */
 260         __u16   ext_header_len; /* Network protocol overhead (IP/IPv6 options) */
 261
 262         __u32   window_clamp;   /* Maximal window to advertise          */
 263         __u32   rcv_ssthresh;   /* Current window clamp                 */
 264
 265         __u32   frto_highmark;  /* snd_nxt when RTO occurred */
 266         __u8    reordering;     /* Packet reordering metric.            */
 267         __u8    frto_counter;   /* Number of new acks after RTO */
 268         __u8    nonagle;        /* Disable Nagle algorithm?             */
 269         __u8    keepalive_probes; /* num of allowed keep alive probes   */
 270
 271 /* RTT measurement */
 272         __u32   srtt;           /* smoothed round trip time << 3        */
 273         __u32   mdev;           /* medium deviation                     */
 274         __u32   mdev_max;       /* maximal mdev for the last rtt period */
 275         __u32   rttvar;         /* smoothed mdev_max                    */
 276         __u32   rtt_seq;        /* sequence number to update rttvar     */
 277
 278         __u32   packets_out;    /* Packets which are "in flight"        */
 279         __u32   left_out;       /* Packets which leaved network */
 280         __u32   retrans_out;    /* Retransmitted packets out            */
 281 /*
 282  *      Options received (usually on last packet, some only on SYN packets).
 283  */
 284         struct tcp_options_received rx_opt;
 285
 286 /*
 287  *      Slow start and congestion control (see also Nagle, and Karn & Partridge)
 288  */
 289         __u32   snd_ssthresh;   /* Slow start size threshold            */
 290         __u32   snd_cwnd;       /* Sending congestion window            */
 291         __u16   snd_cwnd_cnt;   /* Linear increase counter              */
 292         __u16   snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
 293         __u32   snd_cwnd_used;
 294         __u32   snd_cwnd_stamp;
 295
 296         struct sk_buff_head     out_of_order_queue; /* Out of order segments go here */
 297
 298         struct tcp_func         *af_specific;   /* Operations which are AF_INET{4,6} specific   */
 299
 300         __u32   rcv_wnd;        /* Current receiver window              */
 301         __u32   rcv_wup;        /* rcv_nxt on last window update sent   */
 302         __u32   write_seq;      /* Tail(+1) of data held in tcp send buffer */
 303         __u32   pushed_seq;     /* Last pushed seq, required to talk to windows */
 304         __u32   copied_seq;     /* Head of yet unread data              */
 305
 306 /*      SACKs data      */
 307         struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
 308         struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
 309
 310         __u16   advmss;         /* Advertised MSS                       */
 311         __u16   prior_ssthresh; /* ssthresh saved at recovery start     */
 312         __u32   lost_out;       /* Lost packets                 */
 313         __u32   sacked_out;     /* SACK'd packets                       */
 314         __u32   fackets_out;    /* FACK'd packets                       */
 315         __u32   high_seq;       /* snd_nxt at onset of congestion       */
 316
 317         __u32   retrans_stamp;  /* Timestamp of the last retransmit,
 318                                  * also used in SYN-SENT to remember stamp of
 319                                  * the first SYN. */
 320         __u32   undo_marker;    /* tracking retrans started here. */
 321         int     undo_retrans;   /* number of undoable retransmissions. */
 322         __u32   urg_seq;        /* Seq of received urgent pointer */
 323         __u16   urg_data;       /* Saved octet of OOB data and control flags */
 324         __u8    urg_mode;       /* In urgent mode               */
 325         __u8    ecn_flags;      /* ECN status bits.                     */
 326         __u32   snd_up;         /* Urgent pointer               */
 327
 328         __u32   total_retrans;  /* Total retransmits for entire connection */
 329
 330         unsigned int            keepalive_time;   /* time before keep alive takes place */
 331         unsigned int            keepalive_intvl;  /* time interval between keep alive probes */
 332         int                     linger2;
 333
 334         unsigned long last_synq_overflow;
 335
 336 /* Receiver side RTT estimation */
 337         struct {
 338                 __u32   rtt;
 339                 __u32   seq;
 340                 __u32   time;
 341         } rcv_rtt_est;
 342
 343 /* Receiver queue space */
 344         struct {
 345                 int     space;
 346                 __u32   seq;
 347                 __u32   time;
 348         } rcvq_space;
 349 };
 350
 351 static inline struct tcp_sock *tcp_sk(const struct sock *sk)
 352 {
 353         return (struct tcp_sock *)sk;
 354 }
 355
 356 struct tcp_timewait_sock {
 357         struct inet_timewait_sock tw_sk;
 358         __u32                     tw_rcv_nxt;
 359         __u32                     tw_snd_nxt;
 360         __u32                     tw_rcv_wnd;
 361         __u32                     tw_ts_recent;
 362         long                      tw_ts_recent_stamp;
 363 };
 364
 365 static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
 366 {
 367         return (struct tcp_timewait_sock *)sk;
 368 }
 369
 370 #endif
 371
 372 #endif  /* _LINUX_TCP_H */