[unix-history] / usr / src / sys / netinet / tcp_var.h

/*      tcp_var.h       4.15    82/01/17        */

/*
* 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 */
       struct  mbuf *t_ipopt;          /* ip options */
       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_DONTKEEP     0x04                    /* don't use keep-alives */
#define TF_NOOPT        0x08                    /* don't use tcp options */
#ifdef TCPTRUEOOB
#define TF_DOOOB        0x10                    /* do use out of band data */
#endif
       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 */
       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 */
/* transmit timing stuff */
       short   t_idle;                 /* inactivity time */
       short   t_rtt;                  /* round trip time */
       tcp_seq t_rtseq;                /* sequence number being timed */
       float   t_srtt;                 /* smoothed round-trip time */
/* out-of-band data */
       char    t_oobflags;             /* have some */
#define TCPOOB_HAVEDATA 0x01

#ifdef TCPTRUEOOB
#define TCPOOB_OWEACK   0x02
#define TCPOOB_NEEDACK  0x04
       char    t_iobc;                 /* input character */
       u_char  t_iobseq;               /* input receive sequence number */
       char    t_oobc;                 /* output character */
       u_char  t_oobseq;               /* output transmit sequence number */
#endif
};

#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();
#endif