linux/include/linux/tcp.h
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   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#include <linux/socket.h>
  23
  24struct tcphdr {
  25        __be16  source;
  26        __be16  dest;
  27        __be32  seq;
  28        __be32  ack_seq;
  29#if defined(__LITTLE_ENDIAN_BITFIELD)
  30        __u16   res1:4,
  31                doff:4,
  32                fin:1,
  33                syn:1,
  34                rst:1,
  35                psh:1,
  36                ack:1,
  37                urg:1,
  38                ece:1,
  39                cwr:1;
  40#elif defined(__BIG_ENDIAN_BITFIELD)
  41        __u16   doff:4,
  42                res1:4,
  43                cwr:1,
  44                ece:1,
  45                urg:1,
  46                ack:1,
  47                psh:1,
  48                rst:1,
  49                syn:1,
  50                fin:1;
  51#else
  52#error  "Adjust your <asm/byteorder.h> defines"
  53#endif  
  54        __be16  window;
  55        __sum16 check;
  56        __be16  urg_ptr;
  57};
  58
  59/*
  60 *      The union cast uses a gcc extension to avoid aliasing problems
  61 *  (union is compatible to any of its members)
  62 *  This means this part of the code is -fstrict-aliasing safe now.
  63 */
  64union tcp_word_hdr { 
  65        struct tcphdr hdr;
  66        __be32            words[5];
  67}; 
  68
  69#define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3]) 
  70
  71enum { 
  72        TCP_FLAG_CWR = __cpu_to_be32(0x00800000),
  73        TCP_FLAG_ECE = __cpu_to_be32(0x00400000),
  74        TCP_FLAG_URG = __cpu_to_be32(0x00200000),
  75        TCP_FLAG_ACK = __cpu_to_be32(0x00100000),
  76        TCP_FLAG_PSH = __cpu_to_be32(0x00080000),
  77        TCP_FLAG_RST = __cpu_to_be32(0x00040000),
  78        TCP_FLAG_SYN = __cpu_to_be32(0x00020000),
  79        TCP_FLAG_FIN = __cpu_to_be32(0x00010000),
  80        TCP_RESERVED_BITS = __cpu_to_be32(0x0F000000),
  81        TCP_DATA_OFFSET = __cpu_to_be32(0xF0000000)
  82}; 
  83
  84/* TCP socket options */
  85#define TCP_NODELAY             1       /* Turn off Nagle's algorithm. */
  86#define TCP_MAXSEG              2       /* Limit MSS */
  87#define TCP_CORK                3       /* Never send partially complete segments */
  88#define TCP_KEEPIDLE            4       /* Start keeplives after this period */
  89#define TCP_KEEPINTVL           5       /* Interval between keepalives */
  90#define TCP_KEEPCNT             6       /* Number of keepalives before death */
  91#define TCP_SYNCNT              7       /* Number of SYN retransmits */
  92#define TCP_LINGER2             8       /* Life time of orphaned FIN-WAIT-2 state */
  93#define TCP_DEFER_ACCEPT        9       /* Wake up listener only when data arrive */
  94#define TCP_WINDOW_CLAMP        10      /* Bound advertised window */
  95#define TCP_INFO                11      /* Information about this connection. */
  96#define TCP_QUICKACK            12      /* Block/reenable quick acks */
  97#define TCP_CONGESTION          13      /* Congestion control algorithm */
  98#define TCP_MD5SIG              14      /* TCP MD5 Signature (RFC2385) */
  99
 100#define TCPI_OPT_TIMESTAMPS     1
 101#define TCPI_OPT_SACK           2
 102#define TCPI_OPT_WSCALE         4
 103#define TCPI_OPT_ECN            8
 104
 105enum tcp_ca_state
 106{
 107        TCP_CA_Open = 0,
 108#define TCPF_CA_Open    (1<<TCP_CA_Open)
 109        TCP_CA_Disorder = 1,
 110#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
 111        TCP_CA_CWR = 2,
 112#define TCPF_CA_CWR     (1<<TCP_CA_CWR)
 113        TCP_CA_Recovery = 3,
 114#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
 115        TCP_CA_Loss = 4
 116#define TCPF_CA_Loss    (1<<TCP_CA_Loss)
 117};
 118
 119struct tcp_info
 120{
 121        __u8    tcpi_state;
 122        __u8    tcpi_ca_state;
 123        __u8    tcpi_retransmits;
 124        __u8    tcpi_probes;
 125        __u8    tcpi_backoff;
 126        __u8    tcpi_options;
 127        __u8    tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
 128
 129        __u32   tcpi_rto;
 130        __u32   tcpi_ato;
 131        __u32   tcpi_snd_mss;
 132        __u32   tcpi_rcv_mss;
 133
 134        __u32   tcpi_unacked;
 135        __u32   tcpi_sacked;
 136        __u32   tcpi_lost;
 137        __u32   tcpi_retrans;
 138        __u32   tcpi_fackets;
 139
 140        /* Times. */
 141        __u32   tcpi_last_data_sent;
 142        __u32   tcpi_last_ack_sent;     /* Not remembered, sorry. */
 143        __u32   tcpi_last_data_recv;
 144        __u32   tcpi_last_ack_recv;
 145
 146        /* Metrics. */
 147        __u32   tcpi_pmtu;
 148        __u32   tcpi_rcv_ssthresh;
 149        __u32   tcpi_rtt;
 150        __u32   tcpi_rttvar;
 151        __u32   tcpi_snd_ssthresh;
 152        __u32   tcpi_snd_cwnd;
 153        __u32   tcpi_advmss;
 154        __u32   tcpi_reordering;
 155
 156        __u32   tcpi_rcv_rtt;
 157        __u32   tcpi_rcv_space;
 158
 159        __u32   tcpi_total_retrans;
 160};
 161
 162/* for TCP_MD5SIG socket option */
 163#define TCP_MD5SIG_MAXKEYLEN    80
 164
 165struct tcp_md5sig {
 166        struct __kernel_sockaddr_storage tcpm_addr;     /* address associated */
 167        __u16   __tcpm_pad1;                            /* zero */
 168        __u16   tcpm_keylen;                            /* key length */
 169        __u32   __tcpm_pad2;                            /* zero */
 170        __u8    tcpm_key[TCP_MD5SIG_MAXKEYLEN];         /* key (binary) */
 171};
 172
 173#ifdef __KERNEL__
 174
 175#include <linux/skbuff.h>
 176#include <linux/dmaengine.h>
 177#include <net/sock.h>
 178#include <net/inet_connection_sock.h>
 179#include <net/inet_timewait_sock.h>
 180
 181static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb)
 182{
 183        return (struct tcphdr *)skb_transport_header(skb);
 184}
 185
 186static inline unsigned int tcp_hdrlen(const struct sk_buff *skb)
 187{
 188        return tcp_hdr(skb)->doff * 4;
 189}
 190
 191static inline unsigned int tcp_optlen(const struct sk_buff *skb)
 192{
 193        return (tcp_hdr(skb)->doff - 5) * 4;
 194}
 195
 196/* This defines a selective acknowledgement block. */
 197struct tcp_sack_block_wire {
 198        __be32  start_seq;
 199        __be32  end_seq;
 200};
 201
 202struct tcp_sack_block {
 203        u32     start_seq;
 204        u32     end_seq;
 205};
 206
 207struct tcp_options_received {
 208/*      PAWS/RTTM data  */
 209        long    ts_recent_stamp;/* Time we stored ts_recent (for aging) */
 210        u32     ts_recent;      /* Time stamp to echo next              */
 211        u32     rcv_tsval;      /* Time stamp value                     */
 212        u32     rcv_tsecr;      /* Time stamp echo reply                */
 213        u16     saw_tstamp : 1, /* Saw TIMESTAMP on last packet         */
 214                tstamp_ok : 1,  /* TIMESTAMP seen on SYN packet         */
 215                dsack : 1,      /* D-SACK is scheduled                  */
 216                wscale_ok : 1,  /* Wscale seen on SYN packet            */
 217                sack_ok : 4,    /* SACK seen on SYN packet              */
 218                snd_wscale : 4, /* Window scaling received from sender  */
 219                rcv_wscale : 4; /* Window scaling to send to receiver   */
 220/*      SACKs data      */
 221        u8      num_sacks;      /* Number of SACK blocks                */
 222        u16     user_mss;       /* mss requested by user in ioctl */
 223        u16     mss_clamp;      /* Maximal mss, negotiated at connection setup */
 224};
 225
 226/* This is the max number of SACKS that we'll generate and process. It's safe
 227 * to increse this, although since:
 228 *   size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8)
 229 * only four options will fit in a standard TCP header */
 230#define TCP_NUM_SACKS 4
 231
 232struct tcp_request_sock {
 233        struct inet_request_sock        req;
 234#ifdef CONFIG_TCP_MD5SIG
 235        /* Only used by TCP MD5 Signature so far. */
 236        struct tcp_request_sock_ops     *af_specific;
 237#endif
 238        u32                             rcv_isn;
 239        u32                             snt_isn;
 240};
 241
 242static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
 243{
 244        return (struct tcp_request_sock *)req;
 245}
 246
 247struct tcp_sock {
 248        /* inet_connection_sock has to be the first member of tcp_sock */
 249        struct inet_connection_sock     inet_conn;
 250        u16     tcp_header_len; /* Bytes of tcp header to send          */
 251        u16     xmit_size_goal_segs; /* Goal for segmenting output packets */
 252
 253/*
 254 *      Header prediction flags
 255 *      0x5?10 << 16 + snd_wnd in net byte order
 256 */
 257        __be32  pred_flags;
 258
 259/*
 260 *      RFC793 variables by their proper names. This means you can
 261 *      read the code and the spec side by side (and laugh ...)
 262 *      See RFC793 and RFC1122. The RFC writes these in capitals.
 263 */
 264        u32     rcv_nxt;        /* What we want to receive next         */
 265        u32     copied_seq;     /* Head of yet unread data              */
 266        u32     rcv_wup;        /* rcv_nxt on last window update sent   */
 267        u32     snd_nxt;        /* Next sequence we send                */
 268
 269        u32     snd_una;        /* First byte we want an ack for        */
 270        u32     snd_sml;        /* Last byte of the most recently transmitted small packet */
 271        u32     rcv_tstamp;     /* timestamp of last received ACK (for keepalives) */
 272        u32     lsndtime;       /* timestamp of last sent data packet (for restart window) */
 273
 274        /* Data for direct copy to user */
 275        struct {
 276                struct sk_buff_head     prequeue;
 277                struct task_struct      *task;
 278                struct iovec            *iov;
 279                int                     memory;
 280                int                     len;
 281#ifdef CONFIG_NET_DMA
 282                /* members for async copy */
 283                struct dma_chan         *dma_chan;
 284                int                     wakeup;
 285                struct dma_pinned_list  *pinned_list;
 286                dma_cookie_t            dma_cookie;
 287#endif
 288        } ucopy;
 289
 290        u32     snd_wl1;        /* Sequence for window update           */
 291        u32     snd_wnd;        /* The window we expect to receive      */
 292        u32     max_window;     /* Maximal window ever seen from peer   */
 293        u32     mss_cache;      /* Cached effective mss, not including SACKS */
 294
 295        u32     window_clamp;   /* Maximal window to advertise          */
 296        u32     rcv_ssthresh;   /* Current window clamp                 */
 297
 298        u32     frto_highmark;  /* snd_nxt when RTO occurred */
 299        u16     advmss;         /* Advertised MSS                       */
 300        u8      frto_counter;   /* Number of new acks after RTO */
 301        u8      nonagle;        /* Disable Nagle algorithm?             */
 302
 303/* RTT measurement */
 304        u32     srtt;           /* smoothed round trip time << 3        */
 305        u32     mdev;           /* medium deviation                     */
 306        u32     mdev_max;       /* maximal mdev for the last rtt period */
 307        u32     rttvar;         /* smoothed mdev_max                    */
 308        u32     rtt_seq;        /* sequence number to update rttvar     */
 309
 310        u32     packets_out;    /* Packets which are "in flight"        */
 311        u32     retrans_out;    /* Retransmitted packets out            */
 312
 313        u16     urg_data;       /* Saved octet of OOB data and control flags */
 314        u8      ecn_flags;      /* ECN status bits.                     */
 315        u8      reordering;     /* Packet reordering metric.            */
 316        u32     snd_up;         /* Urgent pointer               */
 317
 318        u8      keepalive_probes; /* num of allowed keep alive probes   */
 319/*
 320 *      Options received (usually on last packet, some only on SYN packets).
 321 */
 322        struct tcp_options_received rx_opt;
 323
 324/*
 325 *      Slow start and congestion control (see also Nagle, and Karn & Partridge)
 326 */
 327        u32     snd_ssthresh;   /* Slow start size threshold            */
 328        u32     snd_cwnd;       /* Sending congestion window            */
 329        u32     snd_cwnd_cnt;   /* Linear increase counter              */
 330        u32     snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
 331        u32     snd_cwnd_used;
 332        u32     snd_cwnd_stamp;
 333
 334        u32     rcv_wnd;        /* Current receiver window              */
 335        u32     write_seq;      /* Tail(+1) of data held in tcp send buffer */
 336        u32     pushed_seq;     /* Last pushed seq, required to talk to windows */
 337        u32     lost_out;       /* Lost packets                 */
 338        u32     sacked_out;     /* SACK'd packets                       */
 339        u32     fackets_out;    /* FACK'd packets                       */
 340        u32     tso_deferred;
 341        u32     bytes_acked;    /* Appropriate Byte Counting - RFC3465 */
 342
 343        /* from STCP, retrans queue hinting */
 344        struct sk_buff* lost_skb_hint;
 345        struct sk_buff *scoreboard_skb_hint;
 346        struct sk_buff *retransmit_skb_hint;
 347
 348        struct sk_buff_head     out_of_order_queue; /* Out of order segments go here */
 349
 350        /* SACKs data, these 2 need to be together (see tcp_build_and_update_options) */
 351        struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
 352        struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
 353
 354        struct tcp_sack_block recv_sack_cache[4];
 355
 356        struct sk_buff *highest_sack;   /* highest skb with SACK received
 357                                         * (validity guaranteed only if
 358                                         * sacked_out > 0)
 359                                         */
 360
 361        int     lost_cnt_hint;
 362        u32     retransmit_high;        /* L-bits may be on up to this seqno */
 363
 364        u32     lost_retrans_low;       /* Sent seq after any rxmit (lowest) */
 365
 366        u32     prior_ssthresh; /* ssthresh saved at recovery start     */
 367        u32     high_seq;       /* snd_nxt at onset of congestion       */
 368
 369        u32     retrans_stamp;  /* Timestamp of the last retransmit,
 370                                 * also used in SYN-SENT to remember stamp of
 371                                 * the first SYN. */
 372        u32     undo_marker;    /* tracking retrans started here. */
 373        int     undo_retrans;   /* number of undoable retransmissions. */
 374        u32     total_retrans;  /* Total retransmits for entire connection */
 375
 376        u32     urg_seq;        /* Seq of received urgent pointer */
 377        unsigned int            keepalive_time;   /* time before keep alive takes place */
 378        unsigned int            keepalive_intvl;  /* time interval between keep alive probes */
 379
 380        unsigned long last_synq_overflow; 
 381
 382/* Receiver side RTT estimation */
 383        struct {
 384                u32     rtt;
 385                u32     seq;
 386                u32     time;
 387        } rcv_rtt_est;
 388
 389/* Receiver queue space */
 390        struct {
 391                int     space;
 392                u32     seq;
 393                u32     time;
 394        } rcvq_space;
 395
 396/* TCP-specific MTU probe information. */
 397        struct {
 398                u32               probe_seq_start;
 399                u32               probe_seq_end;
 400        } mtu_probe;
 401
 402#ifdef CONFIG_TCP_MD5SIG
 403/* TCP AF-Specific parts; only used by MD5 Signature support so far */
 404        struct tcp_sock_af_ops  *af_specific;
 405
 406/* TCP MD5 Signagure Option information */
 407        struct tcp_md5sig_info  *md5sig_info;
 408#endif
 409
 410        int                     linger2;
 411};
 412
 413static inline struct tcp_sock *tcp_sk(const struct sock *sk)
 414{
 415        return (struct tcp_sock *)sk;
 416}
 417
 418struct tcp_timewait_sock {
 419        struct inet_timewait_sock tw_sk;
 420        u32                       tw_rcv_nxt;
 421        u32                       tw_snd_nxt;
 422        u32                       tw_rcv_wnd;
 423        u32                       tw_ts_recent;
 424        long                      tw_ts_recent_stamp;
 425#ifdef CONFIG_TCP_MD5SIG
 426        u16                       tw_md5_keylen;
 427        u8                        tw_md5_key[TCP_MD5SIG_MAXKEYLEN];
 428#endif
 429};
 430
 431static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
 432{
 433        return (struct tcp_timewait_sock *)sk;
 434}
 435
 436#endif
 437
 438#endif  /* _LINUX_TCP_H */
 439
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