usr/src/sys/netccitt/llc_timer.c

/*
 * Copyright (C) Dirk Husemann, Computer Science Department IV,
 *               University of Erlangen-Nuremberg, Germany, 1990, 1991, 1992
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Dirk Husemann and the Computer Science Department (IV) of
 * the University of Erlangen-Nuremberg, Germany.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)llc_timer.c 8.1 (Berkeley) %G%
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_llc.h>

#include <netccitt/dll.h>
#include <netccitt/llc_var.h>


/*
 * Various timer values.  They can be adjusted
 * by patching the binary with adb if necessary.
 */
/* ISO 8802-2 timers */
int     llc_n2                  = LLC_N2_VALUE;
int     llc_ACK_timer           = LLC_ACK_TIMER;
int     llc_P_timer             = LLC_P_TIMER;
int     llc_BUSY_timer          = LLC_BUSY_TIMER;
int     llc_REJ_timer           = LLC_REJ_TIMER;
/* Implementation specific timers */
int     llc_AGE_timer           = LLC_AGE_TIMER;
int     llc_DACTION_timer       = LLC_DACTION_TIMER;

/*
 * The timer routine. We are called every 500ms by the kernel.
 * Handle the various virtual timers.
 */

void
llc_timer()
{
        register struct llc_linkcb *linkp;
        register struct llc_linkcb *nlinkp;
        register int timer;
        register int action;
        register int s = splimp();

        /*
         * All links are accessible over the doubly linked list llccb_q
         */
        if (!LQEMPTY) {
                /*
                 * A for-loop is not that great an idea as the linkp
                 * might get deleted if the age timer has expired ...
                 */
                linkp = LQFIRST;
                while (LQVALID(linkp)) {
                        nlinkp = LQNEXT(linkp);
                        /*
                         * Check implementation specific timers first
                         */
                        /* The delayed action/acknowledge idle timer */
                        switch (LLC_TIMERXPIRED(linkp, DACTION)) {
                        case LLC_TIMER_RUNNING:
                                LLC_AGETIMER(linkp, DACTION);
                                break;
                        case LLC_TIMER_EXPIRED: {
                                register int cmdrsp;
                                register int pollfinal;

                                switch (LLC_GETFLAG(linkp, DACTION)) {
                                case LLC_DACKCMD:
                                        cmdrsp = LLC_CMD, pollfinal = 0;
                                        break;
                                case LLC_DACKCMDPOLL:
                                        cmdrsp = LLC_CMD, pollfinal = 1;
                                        break;
                                case LLC_DACKRSP:
                                        cmdrsp = LLC_RSP, pollfinal = 0;
                                        break;
                                case LLC_DACKRSPFINAL:
                                        cmdrsp = LLC_RSP, pollfinal = 1;
                                        break;
                                }
                                llc_send(linkp, LLCFT_RR, cmdrsp, pollfinal);
                                LLC_STOPTIMER(linkp, DACTION);
                                break;
                        }
                        }
                        /* The link idle timer */
                        switch (LLC_TIMERXPIRED(linkp, AGE)) {
                        case LLC_TIMER_RUNNING:
                                LLC_AGETIMER(linkp, AGE);
                                break;
                        case LLC_TIMER_EXPIRED:
                                /*
                                 * Only crunch the link when really no
                                 * timers are running any more.
                                 */
                                if (llc_anytimersup(linkp) == 0) {
                                        llc_dellink(linkp);
                                        LLC_STOPTIMER(linkp, AGE);
                                        goto gone;
                                } else {
                                        LLC_STARTTIMER(linkp, AGE);
                                }
                                break;
                        }
                        /*
                         * Now, check all the ISO 8802-2 timers
                         */
                        FOR_ALL_LLC_TIMERS(timer) {
                                action = 0;
                                if ((linkp->llcl_timerflags & (1<<timer)) &&
                                    (linkp->llcl_timers[timer] == 0)) {
                                        switch (timer) {
                                        case LLC_ACK_SHIFT:
                                                action = LLC_ACK_TIMER_EXPIRED;
                                                break;
                                        case LLC_P_SHIFT:
                                                action = LLC_P_TIMER_EXPIRED;
                                                break;
                                        case LLC_BUSY_SHIFT:
                                                action = LLC_BUSY_TIMER_EXPIRED;
                                                break;
                                        case LLC_REJ_SHIFT:
                                                action = LLC_REJ_TIMER_EXPIRED;
                                                break;
                                        }
                                        linkp->llcl_timerflags &= ~(1<<timer);
                                        (void)llc_statehandler(linkp, (struct llc *)0, action, 0, 1);
                                } else if (linkp->llcl_timers[timer] > 0)
                                        linkp->llcl_timers[timer]--;
                        }

gone:                   linkp = nlinkp;
                }
        }
        splx (s);
}