yet more lint

[unix-history] / usr / src / sys / netinet / tcp_timer.c

/* tcp_timer.c 4.5 81/12/02 */

#include "../h/param.h"
#include "../h/systm.h"
#include "../h/mbuf.h"
#include "../h/socket.h"
#include "../h/socketvar.h"
#include "../h/protosw.h"
#include "../net/in.h"
#include "../net/in_pcb.h"
#include "../net/in_systm.h"
#include "../net/if.h"
#include "../net/ip.h"
#include "../net/ip_var.h"
#include "../net/tcp.h"
#include "../net/tcp_fsm.h"
#include "../net/tcp_seq.h"
#include "../net/tcp_timer.h"
#include "../net/tcp_var.h"
#include "../net/tcpip.h"
#include "../errno.h"

/*
* Fast timeout routine for processing delayed acks
*/
tcp_fasttimo()
{

COUNT(TCP_FASTTIMO);
}

/*
* Tcp protocol timeout routine called every 500 ms.
* Updates the timers in all active tcb's and
* causes finite state machine actions if timers expire.
*/
tcp_slowtimo()
{
       register struct inpcb *ip;
       register struct tcpcb *tp;
       int s = splnet();
       register int i;
COUNT(TCP_SLOWTIMO);

       /*
        * Search through tcb's and update active timers.
        */
       for (ip = tcb.inp_next; ip != &tcb; ip = ip->inp_next) {
               tp = intotcpcb(ip);
               for (i = 0; i < TCPT_NTIMERS; i++) {
                       if (tp->t_timer[i] && --tp->t_timer[i] == 0)
                               (void) tcp_usrreq(tp->t_inpcb->inp_socket,
                                   PRU_SLOWTIMO, (struct mbuf *)0,
                                   (caddr_t)i);
               }
               tp->t_idle++;
               if (tp->t_rtt)
                       tp->t_rtt++;
       }
       tcp_iss += TCP_ISSINCR/PR_SLOWHZ;               /* increment iss */
       splx(s);
}

/*
* Cancel all timers for TCP tp.
*/
tcp_canceltimers(tp)
       struct tcpcb *tp;
{
       register int i;

COUNT(TCP_CANCELTIMERS);
       for (i = 0; i < TCPT_NTIMERS; i++)
               tp->t_timer[i] = 0;
}

/*
* TCP timer processing.
*/
tcp_timers(tp, timer)
       register struct tcpcb *tp;
       int timer;
{

COUNT(TCP_TIMERS);
       switch (timer) {

       /*
        * 2 MSL timeout in shutdown went off.  Delete connection
        * control block.
        */
       case TCPT_2MSL:
               tcp_close(tp);
               return;

       /*
        * Retransmission timer went off.  Message has not
        * been acked within retransmit interval.  Back off
        * to a longer retransmit interval and retransmit all
        * unacknowledged messages in the window.
        */
       case TCPT_REXMT:
               tp->t_rxtshift++;
               TCPT_RANGESET(tp->t_timer[TCPT_REXMT],
                   ((int)(2 * tp->t_srtt)) << tp->t_rxtshift,
                   TCPTV_MIN, TCPTV_MAX);
               tp->snd_nxt = tp->snd_una;
               /* this only transmits one segment! */
               (void) tcp_output(tp);
               return;

       /*
        * Persistance timer into zero window.
        * Force a byte to be output, if possible.
        */
       case TCPT_PERSIST:
               tp->t_force = 1;
               (void) tcp_output(tp);
               tp->t_force = 0;
               TCPT_RANGESET(tp->t_timer[TCPT_PERSIST],
                   2 * tp->t_srtt, TCPTV_PERSMIN, TCPTV_MAX);
               return;

       /*
        * Keep-alive timer went off; send something
        * or drop connection if idle for too long.
        */
       case TCPT_KEEP:
               if (tp->t_state < TCPS_ESTABLISHED ||
                   tp->t_idle >= TCPTV_MAXIDLE) {
                       tcp_drop(tp, ETIMEDOUT);
                       return;
               }
               tcp_respond(tp->t_template, tp->rcv_nxt, tp->snd_una-1, 0);
               tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
               return;
       }
}