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   7.5 (Berkeley) %G%
 */

/*
 * 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 */
        short   t_rxtcur;               /* current retransmit value */
        short   t_dupacks;              /* consecutive dup acks recd */
        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 slow start, source quench, retransmit after loss) */
        u_short snd_cwnd;               /* congestion-controlled window */
        u_short snd_ssthresh;           /* snd_cwnd size threshhold for
                                         * for slow start exponential to
                                         * linear switch */
/*
 * transmit timing stuff.
 * srtt and rttvar are stored as fixed point; for convenience in smoothing,
 * srtt has 3 bits to the right of the binary point, rttvar has 2.
 * "Variance" is actually smoothed difference.
 */
        short   t_idle;                 /* inactivity time */
        short   t_rtt;                  /* round trip time */
        tcp_seq t_rtseq;                /* sequence number being timed */
        short   t_srtt;                 /* smoothed round-trip time */
        short   t_rttvar;               /* variance in round-trip time */
        u_short max_rcvd;               /* most peer has sent into window */
        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)))

/*
 * TCP statistics.
 * Many of these should be kept per connection,
 * but that's inconvenient at the moment.
 */
struct  tcpstat {
        u_long  tcps_connattempt;       /* connections initiated */
        u_long  tcps_accepts;           /* connections accepted */
        u_long  tcps_connects;          /* connections established */
        u_long  tcps_drops;             /* connections dropped */
        u_long  tcps_conndrops;         /* embryonic connections dropped */
        u_long  tcps_closed;            /* conn. closed (includes drops) */
        u_long  tcps_segstimed;         /* segs where we tried to get rtt */
        u_long  tcps_rttupdated;        /* times we succeeded */
        u_long  tcps_delack;            /* delayed acks sent */
        u_long  tcps_timeoutdrop;       /* conn. dropped in rxmt timeout */
        u_long  tcps_rexmttimeo;        /* retransmit timeouts */
        u_long  tcps_persisttimeo;      /* persist timeouts */
        u_long  tcps_keeptimeo;         /* keepalive timeouts */
        u_long  tcps_keepprobe;         /* keepalive probes sent */
        u_long  tcps_keepdrops;         /* connections dropped in keepalive */

        u_long  tcps_sndtotal;          /* total packets sent */
        u_long  tcps_sndpack;           /* data packets sent */
        u_long  tcps_sndbyte;           /* data bytes sent */
        u_long  tcps_sndrexmitpack;     /* data packets retransmitted */
        u_long  tcps_sndrexmitbyte;     /* data bytes retransmitted */
        u_long  tcps_sndacks;           /* ack-only packets sent */
        u_long  tcps_sndprobe;          /* window probes sent */
        u_long  tcps_sndurg;            /* packets sent with URG only */
        u_long  tcps_sndwinup;          /* window update-only packets sent */
        u_long  tcps_sndctrl;           /* control (SYN|FIN|RST) packets sent */

        u_long  tcps_rcvtotal;          /* total packets received */
        u_long  tcps_rcvpack;           /* packets received in sequence */
        u_long  tcps_rcvbyte;           /* bytes received in sequence */
        u_long  tcps_rcvbadsum;         /* packets received with ccksum errs */
        u_long  tcps_rcvbadoff;         /* packets received with bad offset */
        u_long  tcps_rcvshort;          /* packets received too short */
        u_long  tcps_rcvduppack;        /* duplicate-only packets received */
        u_long  tcps_rcvdupbyte;        /* duplicate-only bytes received */
        u_long  tcps_rcvpartduppack;    /* packets with some duplicate data */
        u_long  tcps_rcvpartdupbyte;    /* dup. bytes in part-dup. packets */
        u_long  tcps_rcvoopack;         /* out-of-order packets received */
        u_long  tcps_rcvoobyte;         /* out-of-order bytes received */
        u_long  tcps_rcvpackafterwin;   /* packets with data after window */
        u_long  tcps_rcvbyteafterwin;   /* bytes rcvd after window */
        u_long  tcps_rcvafterclose;     /* packets rcvd after "close" */
        u_long  tcps_rcvwinprobe;       /* rcvd window probe packets */
        u_long  tcps_rcvdupack;         /* rcvd duplicate acks */
        u_long  tcps_rcvacktoomuch;     /* rcvd acks for unsent data */
        u_long  tcps_rcvackpack;        /* rcvd ack packets */
        u_long  tcps_rcvackbyte;        /* bytes acked by rcvd acks */
        u_long  tcps_rcvwinupd;         /* rcvd window update packets */
};

#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