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/*

 * INET         An implementation of the TCP/IP protocol suite for the LINUX

 *              operating system.  INET is implemented using the  BSD Socket

 *              interface as the means of communication with the user level.

 *

 *              Definitions for the TCP protocol.

 *

 * Version:     @(#)tcp.h       1.0.2   04/28/93

 *

 * Author:      Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>

 *

 *              This program is free software; you can redistribute it and/or

 *              modify it under the terms of the GNU General Public License

 *              as published by the Free Software Foundation; either version

 *              2 of the License, or (at your option) any later version.

 */

#ifndef _LINUX_TCP_H

#define _LINUX_TCP_H

#include <linux/types.h>

#include <asm/byteorder.h>

struct tcphdr {

        __u16   source;

        __u16   dest;

        __u32   seq;

        __u32   ack_seq;

#if defined(__LITTLE_ENDIAN_BITFIELD)

        __u16   res1:4,

                doff:4,

                fin:1,

                syn:1,

                rst:1,

                psh:1,

                ack:1,

                urg:1,

                ece:1,

                cwr:1;

#elif defined(__BIG_ENDIAN_BITFIELD)

        __u16   doff:4,

                res1:4,

                cwr:1,

                ece:1,

                urg:1,

                ack:1,

                psh:1,

                rst:1,

                syn:1,

                fin:1;

#else

#error  "Adjust your <asm/byteorder.h> defines"

#endif  

        __u16   window;

        __u16   check;

        __u16   urg_ptr;

};

enum {

  TCP_ESTABLISHED = 1,

  TCP_SYN_SENT,

  TCP_SYN_RECV,

  TCP_FIN_WAIT1,

  TCP_FIN_WAIT2,

  TCP_TIME_WAIT,

  TCP_CLOSE,

  TCP_CLOSE_WAIT,

  TCP_LAST_ACK,

  TCP_LISTEN,

  TCP_CLOSING,   /* now a valid state */

  TCP_MAX_STATES /* Leave at the end! */

};

#define TCP_STATE_MASK  0xF

#define TCP_ACTION_FIN  (1 << 7)

enum {

  TCPF_ESTABLISHED = (1 << 1),

  TCPF_SYN_SENT  = (1 << 2),

  TCPF_SYN_RECV  = (1 << 3),

  TCPF_FIN_WAIT1 = (1 << 4),

  TCPF_FIN_WAIT2 = (1 << 5),

  TCPF_TIME_WAIT = (1 << 6),

  TCPF_CLOSE     = (1 << 7),

  TCPF_CLOSE_WAIT = (1 << 8),

  TCPF_LAST_ACK  = (1 << 9),

  TCPF_LISTEN    = (1 << 10),

  TCPF_CLOSING   = (1 << 11)

};

/*

 *      The union cast uses a gcc extension to avoid aliasing problems

 *  (union is compatible to any of its members)

 *  This means this part of the code is -fstrict-aliasing safe now.

 */

union tcp_word_hdr {

        struct tcphdr hdr;

        __u32             words[5];

};

#define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3]) 

enum {

        TCP_FLAG_CWR = __constant_htonl(0x00800000),

        TCP_FLAG_ECE = __constant_htonl(0x00400000),

        TCP_FLAG_URG = __constant_htonl(0x00200000),

        TCP_FLAG_ACK = __constant_htonl(0x00100000),

        TCP_FLAG_PSH = __constant_htonl(0x00080000),

        TCP_FLAG_RST = __constant_htonl(0x00040000),

        TCP_FLAG_SYN = __constant_htonl(0x00020000),

        TCP_FLAG_FIN = __constant_htonl(0x00010000),

        TCP_RESERVED_BITS = __constant_htonl(0x0F000000),

        TCP_DATA_OFFSET = __constant_htonl(0xF0000000)

};

/* TCP socket options */

#define TCP_NODELAY             1       /* Turn off Nagle's algorithm. */

#define TCP_MAXSEG              2       /* Limit MSS */

#define TCP_CORK                3       /* Never send partially complete segments */

#define TCP_KEEPIDLE            4       /* Start keeplives after this period */

#define TCP_KEEPINTVL           5       /* Interval between keepalives */

#define TCP_KEEPCNT             6       /* Number of keepalives before death */

#define TCP_SYNCNT              7       /* Number of SYN retransmits */

#define TCP_LINGER2             8       /* Life time of orphaned FIN-WAIT-2 state */

#define TCP_DEFER_ACCEPT        9       /* Wake up listener only when data arrive */

#define TCP_WINDOW_CLAMP        10      /* Bound advertised window */

#define TCP_INFO                11      /* Information about this connection. */

#define TCP_QUICKACK            12      /* Block/reenable quick acks */

#define TCPI_OPT_TIMESTAMPS     1

#define TCPI_OPT_SACK           2

#define TCPI_OPT_WSCALE         4

#define TCPI_OPT_ECN            8

enum tcp_ca_state

{

        TCP_CA_Open = 0,

#define TCPF_CA_Open    (1<<TCP_CA_Open)

        TCP_CA_Disorder = 1,

#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)

        TCP_CA_CWR = 2,

#define TCPF_CA_CWR     (1<<TCP_CA_CWR)

        TCP_CA_Recovery = 3,

#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)

        TCP_CA_Loss = 4

#define TCPF_CA_Loss    (1<<TCP_CA_Loss)

};

struct tcp_info

{

        __u8    tcpi_state;

        __u8    tcpi_ca_state;

        __u8    tcpi_retransmits;

        __u8    tcpi_probes;

        __u8    tcpi_backoff;

        __u8    tcpi_options;

        __u8    tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;

        __u32   tcpi_rto;

        __u32   tcpi_ato;

        __u32   tcpi_snd_mss;

        __u32   tcpi_rcv_mss;

        __u32   tcpi_unacked;

        __u32   tcpi_sacked;

        __u32   tcpi_lost;

        __u32   tcpi_retrans;

        __u32   tcpi_fackets;

        /* Times. */

        __u32   tcpi_last_data_sent;

        __u32   tcpi_last_ack_sent;     /* Not remembered, sorry. */

        __u32   tcpi_last_data_recv;

        __u32   tcpi_last_ack_recv;

        /* Metrics. */

        __u32   tcpi_pmtu;

        __u32   tcpi_rcv_ssthresh;

        __u32   tcpi_rtt;

        __u32   tcpi_rttvar;

        __u32   tcpi_snd_ssthresh;

        __u32   tcpi_snd_cwnd;

        __u32   tcpi_advmss;

        __u32   tcpi_reordering;

};

#ifdef __KERNEL__

#include <linux/config.h>

#include <linux/skbuff.h>

#include <linux/ip.h>

#include <net/sock.h>

/* This defines a selective acknowledgement block. */

struct tcp_sack_block {

        __u32   start_seq;

        __u32   end_seq;

};

struct tcp_opt {

        int     tcp_header_len; /* Bytes of tcp header to send          */

/*

 *      Header prediction flags

 *      0x5?10 << 16 + snd_wnd in net byte order

 */

        __u32   pred_flags;

/*

 *      RFC793 variables by their proper names. This means you can

 *      read the code and the spec side by side (and laugh ...)

 *      See RFC793 and RFC1122. The RFC writes these in capitals.

 */

        __u32   rcv_nxt;        /* What we want to receive next         */

        __u32   snd_nxt;        /* Next sequence we send                */

        __u32   snd_una;        /* First byte we want an ack for        */

        __u32   snd_sml;        /* Last byte of the most recently transmitted small packet */

        __u32   rcv_tstamp;     /* timestamp of last received ACK (for keepalives) */

        __u32   lsndtime;       /* timestamp of last sent data packet (for restart window) */

        struct tcp_bind_bucket *bind_hash;

        /* Delayed ACK control data */

        struct {

                __u8    pending;        /* ACK is pending */

                __u8    quick;          /* Scheduled number of quick acks       */

                __u8    pingpong;       /* The session is interactive           */

                __u8    blocked;        /* Delayed ACK was blocked by socket lock*/

                __u32   ato;            /* Predicted tick of soft clock         */

                unsigned long timeout;  /* Currently scheduled timeout          */

                __u32   lrcvtime;       /* timestamp of last received data packet*/

                __u16   last_seg_size;  /* Size of last incoming segment        */

                __u16   rcv_mss;        /* MSS used for delayed ACK decisions   */

        } ack;

        /* Data for direct copy to user */

        struct {

                struct sk_buff_head     prequeue;

                struct task_struct      *task;

                struct iovec            *iov;

                int                     memory;

                int                     len;

        } ucopy;

        __u32   snd_wl1;        /* Sequence for window update           */

        __u32   snd_wnd;        /* The window we expect to receive      */

        __u32   max_window;     /* Maximal window ever seen from peer   */

        __u32   pmtu_cookie;    /* Last pmtu seen by socket             */

        __u32   mss_cache;      /* Cached effective mss, not including SACKS */

        __u16   mss_cache_std;  /* Like mss_cache, but without TSO */

        __u16   mss_clamp;      /* Maximal mss, negotiated at connection setup */

        __u16   ext_header_len; /* Network protocol overhead (IP/IPv6 options) */

        __u16   ext2_header_len;/* Options depending on route */

        __u8    ca_state;       /* State of fast-retransmit machine     */

        __u8    retransmits;    /* Number of unrecovered RTO timeouts.  */

        __u8    reordering;     /* Packet reordering metric.            */

        __u8    queue_shrunk;   /* Write queue has been shrunk recently.*/

        __u8    defer_accept;   /* User waits for some data after accept() */

/* RTT measurement */

        __u8    backoff;        /* backoff                              */

        __u32   srtt;           /* smothed round trip time << 3         */

        __u32   mdev;           /* medium deviation                     */

        __u32   mdev_max;       /* maximal mdev for the last rtt period */

        __u32   rttvar;         /* smoothed mdev_max                    */

        __u32   rtt_seq;        /* sequence number to update rttvar     */

        __u32   rto;            /* retransmit timeout                   */

        __u32   packets_out;    /* Packets which are "in flight"        */

        __u32   left_out;       /* Packets which leaved network         */

        __u32   retrans_out;    /* Retransmitted packets out            */

/*

 *      Slow start and congestion control (see also Nagle, and Karn & Partridge)

 */

        __u32   snd_ssthresh;   /* Slow start size threshold            */

        __u32   snd_cwnd;       /* Sending congestion window            */

        __u16   snd_cwnd_cnt;   /* Linear increase counter              */

        __u16   snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */

        __u32   snd_cwnd_used;

        __u32   snd_cwnd_stamp;

        /* Two commonly used timers in both sender and receiver paths. */

        unsigned long           timeout;

        struct timer_list       retransmit_timer;       /* Resend (no ack)      */

        struct timer_list       delack_timer;           /* Ack delay            */

        struct sk_buff_head     out_of_order_queue; /* Out of order segments go here */

        struct tcp_func         *af_specific;   /* Operations which are AF_INET{4,6} specific   */

        struct sk_buff          *send_head;     /* Front of stuff to transmit                   */

        __u32   rcv_wnd;        /* Current receiver window              */

        __u32   rcv_wup;        /* rcv_nxt on last window update sent   */

        __u32   write_seq;      /* Tail(+1) of data held in tcp send buffer */

        __u32   pushed_seq;     /* Last pushed seq, required to talk to windows */

        __u32   copied_seq;     /* Head of yet unread data              */

/*

 *      Options received (usually on last packet, some only on SYN packets).

 */

        char    tstamp_ok,      /* TIMESTAMP seen on SYN packet         */

                wscale_ok,      /* Wscale seen on SYN packet            */

                sack_ok;        /* SACK seen on SYN packet              */

        char    saw_tstamp;     /* Saw TIMESTAMP on last packet         */

        __u8    snd_wscale;     /* Window scaling received from sender  */

        __u8    rcv_wscale;     /* Window scaling to send to receiver   */

        __u8    nonagle;        /* Disable Nagle algorithm?             */

        __u8    keepalive_probes; /* num of allowed keep alive probes   */

/*      PAWS/RTTM data  */

        __u32   rcv_tsval;      /* Time stamp value                     */

        __u32   rcv_tsecr;      /* Time stamp echo reply                */

        __u32   ts_recent;      /* Time stamp to echo next              */

        long    ts_recent_stamp;/* Time we stored ts_recent (for aging) */

/*      SACKs data      */

        __u16   user_mss;       /* mss requested by user in ioctl */

        __u8    dsack;          /* D-SACK is scheduled                  */

        __u8    eff_sacks;      /* Size of SACK array to send with next packet */

        struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */

        struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/

        __u32   window_clamp;   /* Maximal window to advertise          */

        __u32   rcv_ssthresh;   /* Current window clamp                 */

        __u8    probes_out;     /* unanswered 0 window probes           */

        __u8    num_sacks;      /* Number of SACK blocks                */

        __u16   advmss;         /* Advertised MSS                       */

        __u8    syn_retries;    /* num of allowed syn retries */

        __u8    ecn_flags;      /* ECN status bits.                     */

        __u16   prior_ssthresh; /* ssthresh saved at recovery start     */

        __u32   lost_out;       /* Lost packets                         */

        __u32   sacked_out;     /* SACK'd packets                       */

        __u32   fackets_out;    /* FACK'd packets                       */

        __u32   high_seq;       /* snd_nxt at onset of congestion       */

        __u32   retrans_stamp;  /* Timestamp of the last retransmit,

                                 * also used in SYN-SENT to remember stamp of

                                 * the first SYN. */

        __u32   undo_marker;    /* tracking retrans started here. */

        int     undo_retrans;   /* number of undoable retransmissions. */

        __u32   urg_seq;        /* Seq of received urgent pointer */

        __u16   urg_data;       /* Saved octet of OOB data and control flags */

        __u8    pending;        /* Scheduled timer event        */

        __u8    urg_mode;       /* In urgent mode               */

        __u32   snd_up;         /* Urgent pointer               */

        /* The syn_wait_lock is necessary only to avoid tcp_get_info having

         * to grab the main lock sock while browsing the listening hash

         * (otherwise it's deadlock prone).

         * This lock is acquired in read mode only from tcp_get_info() and

         * it's acquired in write mode _only_ from code that is actively

         * changing the syn_wait_queue. All readers that are holding

         * the master sock lock don't need to grab this lock in read mode

         * too as the syn_wait_queue writes are always protected from

         * the main sock lock.

         */

        rwlock_t                syn_wait_lock;

        struct tcp_listen_opt   *listen_opt;

        /* FIFO of established children */

        struct open_request     *accept_queue;

        struct open_request     *accept_queue_tail;

        int                     write_pending;  /* A write to socket waits to start. */

        unsigned int            keepalive_time;   /* time before keep alive takes place */

        unsigned int            keepalive_intvl;  /* time interval between keep alive probes */

        int                     linger2;

        int                     frto_counter; /* Number of new acks after RTO */

        __u32                   frto_highmark; /* snd_nxt when RTO occurred */

        unsigned long last_synq_overflow;

};

/* WARNING: don't change the layout of the members in tcp_sock! */

struct tcp_sock {

        struct sock       sk;

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)

        struct ipv6_pinfo *pinet6;

#endif

        struct inet_opt   inet;

        struct tcp_opt    tcp;

};

#define tcp_sk(__sk) (&((struct tcp_sock *)__sk)->tcp)

#endif

#endif  /* _LINUX_TCP_H */