for LLC2/2, there may be many pkp's to one xcp;

[unix-history] / usr / src / sys / netccitt / hd_timer.c

/*
* Copyright (c) University of British Columbia, 1984
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Laboratory for Computation Vision and the Computer Science Department
* of the University of British Columbia.
*
* %sccs.include.redist.c%
*
*      @(#)hd_timer.c  7.4 (Berkeley) %G%
*/

#include "param.h"
#include "systm.h"
#include "mbuf.h"
#include "domain.h"
#include "socket.h"
#include "protosw.h"
#include "errno.h"
#include "time.h"
#include "kernel.h"

#include "../net/if.h"

#include "hdlc.h"
#include "hd_var.h"
#include "x25.h"

/*
* these can be patched with adb if the
* default values are inappropriate
*/

int     hd_t1 = T1;
int     hd_t3 = T3;
int     hd_n2 = N2;

/*
*  HDLC TIMER 
*
*  This routine is called every 500ms by the kernel. Decrement timer by this
*  amount - if expired then process the event.
*/

hd_timer ()
{
       register struct hdcb *hdp;
       register int s = splimp ();

       for (hdp = hdcbhead; hdp; hdp = hdp->hd_next) {
               if (hdp->hd_rrtimer && (--hdp->hd_rrtimer == 0)) {
                       if (hdp->hd_lasttxnr != hdp->hd_vr)
                               hd_writeinternal (hdp, RR, POLLOFF);
               }

               if (!(hdp->hd_timer && --hdp->hd_timer == 0))
                       continue;

               switch (hdp->hd_state) {
               case INIT: 
               case DISC_SENT:
                       hd_writeinternal (hdp, DISC, POLLON);
                       break;

               case ABM: 
                       if (hdp->hd_lastrxnr != hdp->hd_vs) {   /* XXX */
                               hdp->hd_timeouts++;
                               hd_resend_iframe (hdp);
                       }
                       break;

               case WAIT_SABM: 
                       hd_writeinternal (hdp, FRMR, POLLOFF);
                       if (++hdp->hd_retxcnt == hd_n2) {
                               hdp->hd_retxcnt = 0;
                               hd_writeinternal (hdp, SABM, POLLOFF);
                               hdp->hd_state = WAIT_UA;
                       }
                       break;

               case DM_SENT: 
                       if (++hdp->hd_retxcnt == hd_n2) {
                               /* Notify the packet level. */
                               (void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp);
                               hdp->hd_retxcnt = 0;
                               hdp->hd_state = SABM_SENT;
                               hd_writeinternal (hdp, SABM, POLLOFF);
                       } else
                               hd_writeinternal (hdp, DM, POLLOFF);
                       break;

               case WAIT_UA: 
                       if (++hdp->hd_retxcnt == hd_n2) {
                               hdp->hd_retxcnt = 0;
                               hd_writeinternal (hdp, DM, POLLOFF);
                               hdp->hd_state = DM_SENT;
                       } else
                               hd_writeinternal (hdp, SABM, POLLOFF);
                       break;

               case SABM_SENT: 
                       /* Do this indefinitely. */
                       hd_writeinternal (hdp, SABM, POLLON);
                       break;

               case DISCONNECTED:
                       /*
                        * Poll the interface driver flags waiting
                        * for the IFF_UP bit to come on.
                        */
                       if (hdp->hd_ifp->if_flags & IFF_UP)
                               hdp->hd_state = INIT;

               }
               SET_TIMER (hdp);
       }

       splx (s);
}