usr/src/sys/netinet/tcp_var.h

/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *      @(#)tcp_var.h   7.1 (Berkeley) 6/5/86
 */

/*
 * Kernel variables for tcp.
 */

/*
 * Tcp control block, one per tcp; fields:
 */
struct tcpcb {
        struct  tcpiphdr *seg_next;     /* sequencing queue */
        struct  tcpiphdr *seg_prev;
        short   t_state;                /* state of this connection */
        short   t_timer[TCPT_NTIMERS];  /* tcp timers */
        short   t_rxtshift;             /* log(2) of rexmt exp. backoff */
        struct  mbuf *t_tcpopt;         /* tcp options */
        u_short t_maxseg;               /* maximum segment size */
        char    t_force;                /* 1 if forcing out a byte */
        u_char  t_flags;
#define TF_ACKNOW       0x01            /* ack peer immediately */
#define TF_DELACK       0x02            /* ack, but try to delay it */
#define TF_NODELAY      0x04            /* don't delay packets to coalesce */
#define TF_NOOPT        0x08            /* don't use tcp options */
#define TF_SENTFIN      0x10            /* have sent FIN */
        struct  tcpiphdr *t_template;   /* skeletal packet for transmit */
        struct  inpcb *t_inpcb;         /* back pointer to internet pcb */
/*
 * The following fields are used as in the protocol specification.
 * See RFC783, Dec. 1981, page 21.
 */
/* send sequence variables */
        tcp_seq snd_una;                /* send unacknowledged */
        tcp_seq snd_nxt;                /* send next */
        tcp_seq snd_up;                 /* send urgent pointer */
        tcp_seq snd_wl1;                /* window update seg seq number */
        tcp_seq snd_wl2;                /* window update seg ack number */
        tcp_seq iss;                    /* initial send sequence number */
        u_short snd_wnd;                /* send window */
/* receive sequence variables */
        u_short rcv_wnd;                /* receive window */
        tcp_seq rcv_nxt;                /* receive next */
        tcp_seq rcv_up;                 /* receive urgent pointer */
        tcp_seq irs;                    /* initial receive sequence number */
/*
 * Additional variables for this implementation.
 */
/* receive variables */
        tcp_seq rcv_adv;                /* advertised window */
/* retransmit variables */
        tcp_seq snd_max;                /* highest sequence number sent
                                         * used to recognize retransmits
                                         */
/* congestion control (for source quench) */
        u_short snd_cwnd;               /* congestion-controlled window */
/* transmit timing stuff */
        short   t_idle;                 /* inactivity time */
        short   t_rtt;                  /* round trip time */
        u_short max_rcvd;               /* most peer has sent into window */
        tcp_seq t_rtseq;                /* sequence number being timed */
        float   t_srtt;                 /* smoothed round-trip time */
        u_short max_sndwnd;             /* largest window peer has offered */
/* out-of-band data */
        char    t_oobflags;             /* have some */
        char    t_iobc;                 /* input character */
#define TCPOOB_HAVEDATA 0x01
#define TCPOOB_HADDATA  0x02
};

#define intotcpcb(ip)   ((struct tcpcb *)(ip)->inp_ppcb)
#define sototcpcb(so)   (intotcpcb(sotoinpcb(so)))

struct  tcpstat {
        int     tcps_badsum;
        int     tcps_badoff;
        int     tcps_hdrops;
        int     tcps_badsegs;
        int     tcps_unack;
};

#ifdef KERNEL
struct  inpcb tcb;              /* head of queue of active tcpcb's */
struct  tcpstat tcpstat;        /* tcp statistics */
struct  tcpiphdr *tcp_template();
struct  tcpcb *tcp_close(), *tcp_drop();
struct  tcpcb *tcp_timers(), *tcp_disconnect(), *tcp_usrclosed();
#endif