4.3BSD - /usr/src/etc/XNSrouted/timer.c

   1: /*
   2:  * Copyright (c) 1985 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  *
   6:  * Includes material written at Cornell University by Bill Nesheim,
   7:  * by permission of the author.
   8:  */
   9: 
  10: 
  11: #ifndef lint
  12: static char sccsid[] = "@(#)timer.c	5.4 (Berkeley) 2/14/86";
  13: #endif not lint
  14: 
  15: /*
  16:  * Routing Table Management Daemon
  17:  */
  18: #include "defs.h"
  19: 
  20: int timeval = -TIMER_RATE;
  21: 
  22: /*
  23:  * Timer routine.  Performs routing information supply
  24:  * duties and manages timers on routing table entries.
  25:  */
  26: timer()
  27: {
  28:     register struct rthash *rh;
  29:     register struct rt_entry *rt;
  30:     struct rthash *base = hosthash;
  31:     int doinghost = 1, timetobroadcast;
  32: 
  33:     timeval += TIMER_RATE;
  34:     if (lookforinterfaces && (timeval % CHECK_INTERVAL) == 0)
  35:         ifinit();
  36:     timetobroadcast = supplier && (timeval % SUPPLY_INTERVAL) == 0;
  37: again:
  38:     for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) {
  39:         rt = rh->rt_forw;
  40:         for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
  41:             /*
  42: 			 * We don't advance time on a routing entry for
  43: 			 * a passive gateway or that for our only interface.
  44: 			 * The latter is excused because we don't act as
  45: 			 * a routing information supplier and hence would
  46: 			 * time it out.  This is fair as if it's down
  47: 			 * we're cut off from the world anyway and it's
  48: 			 * not likely we'll grow any new hardware in
  49: 			 * the mean time.
  50: 			 */
  51:             if (!(rt->rt_state & RTS_PASSIVE) &&
  52:                 (supplier || !(rt->rt_state & RTS_INTERFACE)))
  53:                 rt->rt_timer += TIMER_RATE;
  54:             if (rt->rt_timer >= EXPIRE_TIME)
  55:                 rt->rt_metric = HOPCNT_INFINITY;
  56:             if (rt->rt_timer >= GARBAGE_TIME) {
  57:                 rt = rt->rt_back;
  58:                 /* Perhaps we should send a REQUEST for this route? */
  59:                 rtdelete(rt->rt_forw);
  60:                 continue;
  61:             }
  62:             if (rt->rt_state & RTS_CHANGED) {
  63:                 rt->rt_state &= ~RTS_CHANGED;
  64:                 /* don't send extraneous packets */
  65:                 if (!supplier || timetobroadcast)
  66:                     continue;
  67:                 msg->rip_cmd = htons(RIPCMD_RESPONSE);
  68:                 msg->rip_nets[0].rip_dst =
  69:                     (satons_addr(rt->rt_dst)).x_net;
  70:                 msg->rip_nets[0].rip_metric =
  71:                     htons(min(rt->rt_metric+1, HOPCNT_INFINITY));
  72:                 toall(sendmsg);
  73:             }
  74:         }
  75:     }
  76:     if (doinghost) {
  77:         doinghost = 0;
  78:         base = nethash;
  79:         goto again;
  80:     }
  81:     if (timetobroadcast)
  82:         toall(supply);
  83:     alarm(TIMER_RATE);
  84: }
  85: 
  86: /*
  87:  * On hangup, let everyone know we're going away.
  88:  */
  89: hup()
  90: {
  91:     register struct rthash *rh;
  92:     register struct rt_entry *rt;
  93:     struct rthash *base = hosthash;
  94:     int doinghost = 1;
  95: 
  96:     if (supplier) {
  97: again:
  98:         for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) {
  99:             rt = rh->rt_forw;
 100:             for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw)
 101:                 rt->rt_metric = HOPCNT_INFINITY;
 102:         }
 103:         if (doinghost) {
 104:             doinghost = 0;
 105:             base = nethash;
 106:             goto again;
 107:         }
 108:         toall(supply);
 109:     }
 110:     exit(1);
 111: }

Defined functions

Defined variables