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root/include/linux/tcp.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. __constant_htonl
  2. __constant_htonl
  3. __constant_htonl
  4. __constant_htonl
  5. __constant_htonl
  6. __constant_htonl
  7. __constant_htonl
  8. __constant_htonl
  9. __constant_htonl
  10. __constant_htonl
  11. tcp_hdr
  12. tcp_hdrlen
  13. tcp_optlen
  14. tcp_rsk
  15. tcp_sk
  16. tcp_twsk

/*
 * 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>
#include <linux/socket.h>

struct tcphdr {
        __be16  source;
        __be16  dest;
        __be32  seq;
        __be32  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  
        __be16  window;
        __sum16 check;
        __be16  urg_ptr;
};

/*
 *      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;
        __be32            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 TCP_CONGESTION          13      /* Congestion control algorithm */
#define TCP_MD5SIG              14      /* TCP MD5 Signature (RFC2385) */

#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;

        __u32   tcpi_rcv_rtt;
        __u32   tcpi_rcv_space;

        __u32   tcpi_total_retrans;
};

/* for TCP_MD5SIG socket option */
#define TCP_MD5SIG_MAXKEYLEN    80

struct tcp_md5sig {
        struct __kernel_sockaddr_storage tcpm_addr;     /* address associated */
        __u16   __tcpm_pad1;                            /* zero */
        __u16   tcpm_keylen;                            /* key length */
        __u32   __tcpm_pad2;                            /* zero */
        __u8    tcpm_key[TCP_MD5SIG_MAXKEYLEN];         /* key (binary) */
};

#ifdef __KERNEL__

#include <linux/skbuff.h>
#include <linux/dmaengine.h>
#include <net/sock.h>
#include <net/inet_connection_sock.h>
#include <net/inet_timewait_sock.h>

static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb)
{
        return (struct tcphdr *)skb_transport_header(skb);
}

static inline unsigned int tcp_hdrlen(const struct sk_buff *skb)
{
        return tcp_hdr(skb)->doff * 4;
}

static inline unsigned int tcp_optlen(const struct sk_buff *skb)
{
        return (tcp_hdr(skb)->doff - 5) * 4;
}

/* This defines a selective acknowledgement block. */
struct tcp_sack_block_wire {
        __be32  start_seq;
        __be32  end_seq;
};

struct tcp_sack_block {
        u32     start_seq;
        u32     end_seq;
};

struct tcp_options_received {
/*      PAWS/RTTM data  */
        long    ts_recent_stamp;/* Time we stored ts_recent (for aging) */
        u32     ts_recent;      /* Time stamp to echo next              */
        u32     rcv_tsval;      /* Time stamp value                     */
        u32     rcv_tsecr;      /* Time stamp echo reply                */
        u16     saw_tstamp : 1, /* Saw TIMESTAMP on last packet         */
                tstamp_ok : 1,  /* TIMESTAMP seen on SYN packet         */
                dsack : 1,      /* D-SACK is scheduled                  */
                wscale_ok : 1,  /* Wscale seen on SYN packet            */
                sack_ok : 4,    /* SACK seen on SYN packet              */
                snd_wscale : 4, /* Window scaling received from sender  */
                rcv_wscale : 4; /* Window scaling to send to receiver   */
/*      SACKs data      */
        u8      eff_sacks;      /* Size of SACK array to send with next packet */
        u8      num_sacks;      /* Number of SACK blocks                */
        u16     user_mss;       /* mss requested by user in ioctl */
        u16     mss_clamp;      /* Maximal mss, negotiated at connection setup */
};

/* This is the max number of SACKS that we'll generate and process. It's safe
 * to increse this, although since:
 *   size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8)
 * only four options will fit in a standard TCP header */
#define TCP_NUM_SACKS 4

struct tcp_request_sock {
        struct inet_request_sock        req;
#ifdef CONFIG_TCP_MD5SIG
        /* Only used by TCP MD5 Signature so far. */
        struct tcp_request_sock_ops     *af_specific;
#endif
        u32                             rcv_isn;
        u32                             snt_isn;
};

static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
{
        return (struct tcp_request_sock *)req;
}

struct tcp_sock {
        /* inet_connection_sock has to be the first member of tcp_sock */
        struct inet_connection_sock     inet_conn;
        u16     tcp_header_len; /* Bytes of tcp header to send          */
        u16     xmit_size_goal; /* Goal for segmenting output packets   */

/*
 *      Header prediction flags
 *      0x5?10 << 16 + snd_wnd in net byte order
 */
        __be32  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     copied_seq;     /* Head of yet unread data              */
        u32     rcv_wup;        /* rcv_nxt on last window update sent   */
        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) */

        /* Data for direct copy to user */
        struct {
                struct sk_buff_head     prequeue;
                struct task_struct      *task;
                struct iovec            *iov;
                int                     memory;
                int                     len;
#ifdef CONFIG_NET_DMA
                /* members for async copy */
                struct dma_chan         *dma_chan;
                int                     wakeup;
                struct dma_pinned_list  *pinned_list;
                dma_cookie_t            dma_cookie;
#endif
        } 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     mss_cache;      /* Cached effective mss, not including SACKS */

        u32     window_clamp;   /* Maximal window to advertise          */
        u32     rcv_ssthresh;   /* Current window clamp                 */

        u32     frto_highmark;  /* snd_nxt when RTO occurred */
        u16     advmss;         /* Advertised MSS                       */
        u8      frto_counter;   /* Number of new acks after RTO */
        u8      nonagle;        /* Disable Nagle algorithm?             */

/* RTT measurement */
        u32     srtt;           /* smoothed 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     packets_out;    /* Packets which are "in flight"        */
        u32     retrans_out;    /* Retransmitted packets out            */

        u16     urg_data;       /* Saved octet of OOB data and control flags */
        u8      ecn_flags;      /* ECN status bits.                     */
        u8      reordering;     /* Packet reordering metric.            */
        u32     snd_up;         /* Urgent pointer               */

        u8      keepalive_probes; /* num of allowed keep alive probes   */
/*
 *      Options received (usually on last packet, some only on SYN packets).
 */
        struct tcp_options_received rx_opt;

/*
 *      Slow start and congestion control (see also Nagle, and Karn & Partridge)
 */
        u32     snd_ssthresh;   /* Slow start size threshold            */
        u32     snd_cwnd;       /* Sending congestion window            */
        u32     snd_cwnd_cnt;   /* Linear increase counter              */
        u32     snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
        u32     snd_cwnd_used;
        u32     snd_cwnd_stamp;

        u32     rcv_wnd;        /* Current receiver window              */
        u32     write_seq;      /* Tail(+1) of data held in tcp send buffer */
        u32     pushed_seq;     /* Last pushed seq, required to talk to windows */
        u32     lost_out;       /* Lost packets                 */
        u32     sacked_out;     /* SACK'd packets                       */
        u32     fackets_out;    /* FACK'd packets                       */
        u32     tso_deferred;
        u32     bytes_acked;    /* Appropriate Byte Counting - RFC3465 */

        /* from STCP, retrans queue hinting */
        struct sk_buff* lost_skb_hint;
        struct sk_buff *scoreboard_skb_hint;
        struct sk_buff *retransmit_skb_hint;

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

        /* SACKs data, these 2 need to be together (see tcp_build_and_update_options) */
        struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
        struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/

        struct tcp_sack_block recv_sack_cache[4];

        struct sk_buff *highest_sack;   /* highest skb with SACK received
                                         * (validity guaranteed only if
                                         * sacked_out > 0)
                                         */

        int     lost_cnt_hint;
        u32     retransmit_high;        /* L-bits may be on up to this seqno */

        u32     lost_retrans_low;       /* Sent seq after any rxmit (lowest) */

        u32     prior_ssthresh; /* ssthresh saved at recovery start     */
        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     total_retrans;  /* Total retransmits for entire connection */

        u32     urg_seq;        /* Seq of received urgent pointer */
        unsigned int            keepalive_time;   /* time before keep alive takes place */
        unsigned int            keepalive_intvl;  /* time interval between keep alive probes */

        unsigned long last_synq_overflow; 

/* Receiver side RTT estimation */
        struct {
                u32     rtt;
                u32     seq;
                u32     time;
        } rcv_rtt_est;

/* Receiver queue space */
        struct {
                int     space;
                u32     seq;
                u32     time;
        } rcvq_space;

/* TCP-specific MTU probe information. */
        struct {
                u32               probe_seq_start;
                u32               probe_seq_end;
        } mtu_probe;

#ifdef CONFIG_TCP_MD5SIG
/* TCP AF-Specific parts; only used by MD5 Signature support so far */
        struct tcp_sock_af_ops  *af_specific;

/* TCP MD5 Signagure Option information */
        struct tcp_md5sig_info  *md5sig_info;
#endif

        int                     linger2;
};

static inline struct tcp_sock *tcp_sk(const struct sock *sk)
{
        return (struct tcp_sock *)sk;
}

struct tcp_timewait_sock {
        struct inet_timewait_sock tw_sk;
        u32                       tw_rcv_nxt;
        u32                       tw_snd_nxt;
        u32                       tw_rcv_wnd;
        u32                       tw_ts_recent;
        long                      tw_ts_recent_stamp;
#ifdef CONFIG_TCP_MD5SIG
        u16                       tw_md5_keylen;
        u8                        tw_md5_key[TCP_MD5SIG_MAXKEYLEN];
#endif
};

static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
{
        return (struct tcp_timewait_sock *)sk;
}

#endif

#endif  /* _LINUX_TCP_H */

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