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 #include <linux/socket.h>
  23
  24 struct 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         __be16  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  */
  64 union 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
  71 enum {
  72         TCP_FLAG_CWR = __constant_htonl(0x00800000),
  73         TCP_FLAG_ECE = __constant_htonl(0x00400000),
  74         TCP_FLAG_URG = __constant_htonl(0x00200000),
  75         TCP_FLAG_ACK = __constant_htonl(0x00100000),
  76         TCP_FLAG_PSH = __constant_htonl(0x00080000),
  77         TCP_FLAG_RST = __constant_htonl(0x00040000),
  78         TCP_FLAG_SYN = __constant_htonl(0x00020000),
  79         TCP_FLAG_FIN = __constant_htonl(0x00010000),
  80         TCP_RESERVED_BITS = __constant_htonl(0x0F000000),
  81         TCP_DATA_OFFSET = __constant_htonl(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
 105 enum 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
 119 struct 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
 165 struct 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
 181 /* This defines a selective acknowledgement block. */
 182 struct tcp_sack_block_wire {
 183         __be32  start_seq;
 184         __be32  end_seq;
 185 };
 186
 187 struct tcp_sack_block {
 188         __u32   start_seq;
 189         __u32   end_seq;
 190 };
 191
 192 struct tcp_options_received {
 193 /*      PAWS/RTTM data  */
 194         long    ts_recent_stamp;/* Time we stored ts_recent (for aging) */
 195         __u32   ts_recent;      /* Time stamp to echo next              */
 196         __u32   rcv_tsval;      /* Time stamp value                     */
 197         __u32   rcv_tsecr;      /* Time stamp echo reply                */
 198         __u16   saw_tstamp : 1, /* Saw TIMESTAMP on last packet         */
 199                 tstamp_ok : 1,  /* TIMESTAMP seen on SYN packet         */
 200                 dsack : 1,      /* D-SACK is scheduled                  */
 201                 wscale_ok : 1,  /* Wscale seen on SYN packet            */
 202                 sack_ok : 4,    /* SACK seen on SYN packet              */
 203                 snd_wscale : 4, /* Window scaling received from sender  */
 204                 rcv_wscale : 4; /* Window scaling to send to receiver   */
 205 /*      SACKs data      */
 206         __u8    eff_sacks;      /* Size of SACK array to send with next packet */
 207         __u8    num_sacks;      /* Number of SACK blocks                */
 208         __u16   user_mss;       /* mss requested by user in ioctl */
 209         __u16   mss_clamp;      /* Maximal mss, negotiated at connection setup */
 210 };
 211
 212 struct tcp_request_sock {
 213         struct inet_request_sock        req;
 214 #ifdef CONFIG_TCP_MD5SIG
 215         /* Only used by TCP MD5 Signature so far. */
 216         struct tcp_request_sock_ops     *af_specific;
 217 #endif
 218         __u32                           rcv_isn;
 219         __u32                           snt_isn;
 220 };
 221
 222 static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
 223 {
 224         return (struct tcp_request_sock *)req;
 225 }
 226
 227 struct tcp_sock {
 228         /* inet_connection_sock has to be the first member of tcp_sock */
 229         struct inet_connection_sock     inet_conn;
 230         int     tcp_header_len; /* Bytes of tcp header to send          */
 231
 232 /*
 233  *      Header prediction flags
 234  *      0x5?10 << 16 + snd_wnd in net byte order
 235  */
 236         __be32  pred_flags;
 237
 238 /*
 239  *      RFC793 variables by their proper names. This means you can
 240  *      read the code and the spec side by side (and laugh ...)
 241  *      See RFC793 and RFC1122. The RFC writes these in capitals.
 242  */
 243         __u32   rcv_nxt;        /* What we want to receive next         */
 244         __u32   snd_nxt;        /* Next sequence we send                */
 245
 246         __u32   snd_una;        /* First byte we want an ack for        */
 247         __u32   snd_sml;        /* Last byte of the most recently transmitted small packet */
 248         __u32   rcv_tstamp;     /* timestamp of last received ACK (for keepalives) */
 249         __u32   lsndtime;       /* timestamp of last sent data packet (for restart window) */
 250
 251         /* Data for direct copy to user */
 252         struct {
 253                 struct sk_buff_head     prequeue;
 254                 struct task_struct      *task;
 255                 struct iovec            *iov;
 256                 int                     memory;
 257                 int                     len;
 258 #ifdef CONFIG_NET_DMA
 259                 /* members for async copy */
 260                 struct dma_chan         *dma_chan;
 261                 int                     wakeup;
 262                 struct dma_pinned_list  *pinned_list;
 263                 dma_cookie_t            dma_cookie;
 264 #endif
 265         } ucopy;
 266
 267         __u32   snd_wl1;        /* Sequence for window update           */
 268         __u32   snd_wnd;        /* The window we expect to receive      */
 269         __u32   max_window;     /* Maximal window ever seen from peer   */
 270         __u32   mss_cache;      /* Cached effective mss, not including SACKS */
 271         __u16   xmit_size_goal; /* Goal for segmenting output packets   */
 272         /* XXX Two bytes hole, try to pack */
 273
 274         __u32   window_clamp;   /* Maximal window to advertise          */
 275         __u32   rcv_ssthresh;   /* Current window clamp                 */
 276
 277         __u32   frto_highmark;  /* snd_nxt when RTO occurred */
 278         __u8    reordering;     /* Packet reordering metric.            */
 279         __u8    frto_counter;   /* Number of new acks after RTO */
 280         __u8    nonagle;        /* Disable Nagle algorithm?             */
 281         __u8    keepalive_probes; /* num of allowed keep alive probes   */
 282
 283 /* RTT measurement */
 284         __u32   srtt;           /* smoothed round trip time << 3        */
 285         __u32   mdev;           /* medium deviation                     */
 286         __u32   mdev_max;       /* maximal mdev for the last rtt period */
 287         __u32   rttvar;         /* smoothed mdev_max                    */
 288         __u32   rtt_seq;        /* sequence number to update rttvar     */
 289
 290         __u32   packets_out;    /* Packets which are "in flight"        */
 291         __u32   left_out;       /* Packets which leaved network */
 292         __u32   retrans_out;    /* Retransmitted packets out            */
 293 /*
 294  *      Options received (usually on last packet, some only on SYN packets).
 295  */
 296         struct tcp_options_received rx_opt;
 297
 298 /*
 299  *      Slow start and congestion control (see also Nagle, and Karn & Partridge)
 300  */
 301         __u32   snd_ssthresh;   /* Slow start size threshold            */
 302         __u32   snd_cwnd;       /* Sending congestion window            */
 303         __u16   snd_cwnd_cnt;   /* Linear increase counter              */
 304         __u16   snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
 305         __u32   snd_cwnd_used;
 306         __u32   snd_cwnd_stamp;
 307
 308         struct sk_buff_head     out_of_order_queue; /* Out of order segments go here */
 309
 310         __u32   rcv_wnd;        /* Current receiver window              */
 311         __u32   rcv_wup;        /* rcv_nxt on last window update sent   */
 312         __u32   write_seq;      /* Tail(+1) of data held in tcp send buffer */
 313         __u32   pushed_seq;     /* Last pushed seq, required to talk to windows */
 314         __u32   copied_seq;     /* Head of yet unread data              */
 315
 316 /*      SACKs data      */
 317         struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
 318         struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
 319
 320         struct tcp_sack_block recv_sack_cache[4];
 321
 322         /* from STCP, retrans queue hinting */
 323         struct sk_buff* lost_skb_hint;
 324
 325         struct sk_buff *scoreboard_skb_hint;
 326         struct sk_buff *retransmit_skb_hint;
 327         struct sk_buff *forward_skb_hint;
 328         struct sk_buff *fastpath_skb_hint;
 329
 330         int     fastpath_cnt_hint;
 331         int     lost_cnt_hint;
 332         int     retransmit_cnt_hint;
 333         int     forward_cnt_hint;
 334
 335         __u16   advmss;         /* Advertised MSS                       */
 336         __u16   prior_ssthresh; /* ssthresh saved at recovery start     */
 337         __u32   lost_out;       /* Lost packets                 */
 338         __u32   sacked_out;     /* SACK'd packets                       */
 339         __u32   fackets_out;    /* FACK'd packets                       */
 340         __u32   high_seq;       /* snd_nxt at onset of congestion       */
 341
 342         __u32   retrans_stamp;  /* Timestamp of the last retransmit,
 343                                  * also used in SYN-SENT to remember stamp of
 344                                  * the first SYN. */
 345         __u32   undo_marker;    /* tracking retrans started here. */
 346         int     undo_retrans;   /* number of undoable retransmissions. */
 347         __u32   urg_seq;        /* Seq of received urgent pointer */
 348         __u16   urg_data;       /* Saved octet of OOB data and control flags */
 349         __u8    urg_mode;       /* In urgent mode               */
 350         __u8    ecn_flags;      /* ECN status bits.                     */
 351         __u32   snd_up;         /* Urgent pointer               */
 352
 353         __u32   total_retrans;  /* Total retransmits for entire connection */
 354         __u32   bytes_acked;    /* Appropriate Byte Counting - RFC3465 */
 355
 356         unsigned int            keepalive_time;   /* time before keep alive takes place */
 357         unsigned int            keepalive_intvl;  /* time interval between keep alive probes */
 358         int                     linger2;
 359
 360         unsigned long last_synq_overflow;
 361
 362         __u32   tso_deferred;
 363
 364 /* Receiver side RTT estimation */
 365         struct {
 366                 __u32   rtt;
 367                 __u32   seq;
 368                 __u32   time;
 369         } rcv_rtt_est;
 370
 371 /* Receiver queue space */
 372         struct {
 373                 int     space;
 374                 __u32   seq;
 375                 __u32   time;
 376         } rcvq_space;
 377
 378 /* TCP-specific MTU probe information. */
 379         struct {
 380                 __u32             probe_seq_start;
 381                 __u32             probe_seq_end;
 382         } mtu_probe;
 383
 384 #ifdef CONFIG_TCP_MD5SIG
 385 /* TCP AF-Specific parts; only used by MD5 Signature support so far */
 386         struct tcp_sock_af_ops  *af_specific;
 387
 388 /* TCP MD5 Signagure Option information */
 389         struct tcp_md5sig_info  *md5sig_info;
 390 #endif
 391 };
 392
 393 static inline struct tcp_sock *tcp_sk(const struct sock *sk)
 394 {
 395         return (struct tcp_sock *)sk;
 396 }
 397
 398 struct tcp_timewait_sock {
 399         struct inet_timewait_sock tw_sk;
 400         __u32                     tw_rcv_nxt;
 401         __u32                     tw_snd_nxt;
 402         __u32                     tw_rcv_wnd;
 403         __u32                     tw_ts_recent;
 404         long                      tw_ts_recent_stamp;
 405 #ifdef CONFIG_TCP_MD5SIG
 406         __u16                     tw_md5_keylen;
 407         __u8                      tw_md5_key[TCP_MD5SIG_MAXKEYLEN];
 408 #endif
 409 };
 410
 411 static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
 412 {
 413         return (struct tcp_timewait_sock *)sk;
 414 }
 415
 416 #endif
 417
 418 #endif  /* _LINUX_TCP_H */