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Annotation of 42BSD/etc/routed/timer.c, revision 1.1.1.1

1.1       root        1: #ifndef lint
                      2: static char sccsid[] = "@(#)timer.c    4.4 (Berkeley) 6/1/83";
                      3: #endif
                      4: 
                      5: /*
                      6:  * Routing Table Management Daemon
                      7:  */
                      8: #include "defs.h"
                      9: 
                     10: int    timeval = -TIMER_RATE;
                     11: 
                     12: /*
                     13:  * Timer routine.  Performs routing information supply
                     14:  * duties and manages timers on routing table entries.
                     15:  */
                     16: timer()
                     17: {
                     18:        register struct rthash *rh;
                     19:        register struct rt_entry *rt;
                     20:        struct rthash *base = hosthash;
                     21:        int doinghost = 1, timetobroadcast;
                     22: 
                     23:        timeval += TIMER_RATE;
                     24:        if (lookforinterfaces && (timeval % CHECK_INTERVAL) == 0)
                     25:                ifinit();
                     26:        timetobroadcast = supplier && (timeval % SUPPLY_INTERVAL) == 0;
                     27: again:
                     28:        for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) {
                     29:                rt = rh->rt_forw;
                     30:                for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
                     31:                        /*
                     32:                         * We don't advance time on a routing entry for
                     33:                         * a passive gateway or that for our only interface. 
                     34:                         * The latter is excused because we don't act as
                     35:                         * a routing information supplier and hence would
                     36:                         * time it out.  This is fair as if it's down
                     37:                         * we're cut off from the world anyway and it's
                     38:                         * not likely we'll grow any new hardware in
                     39:                         * the mean time.
                     40:                         */
                     41:                        if (!(rt->rt_state & RTS_PASSIVE) &&
                     42:                            (supplier || !(rt->rt_state & RTS_INTERFACE)))
                     43:                                rt->rt_timer += TIMER_RATE;
                     44:                        if (rt->rt_timer >= EXPIRE_TIME)
                     45:                                rt->rt_metric = HOPCNT_INFINITY;
                     46:                        if (rt->rt_timer >= GARBAGE_TIME) {
                     47:                                rt = rt->rt_back;
                     48:                                rtdelete(rt->rt_forw);
                     49:                                continue;
                     50:                        }
                     51:                        if (rt->rt_state & RTS_CHANGED) {
                     52:                                rt->rt_state &= ~RTS_CHANGED;
                     53:                                /* don't send extraneous packets */
                     54:                                if (!supplier || timetobroadcast)
                     55:                                        continue;
                     56:                                msg->rip_cmd = RIPCMD_RESPONSE;
                     57:                                msg->rip_vers = RIPVERSION;
                     58:                                msg->rip_nets[0].rip_dst = rt->rt_dst;
                     59:                                msg->rip_nets[0].rip_dst.sa_family =
                     60:                                   htons(msg->rip_nets[0].rip_dst.sa_family);
                     61:                                msg->rip_nets[0].rip_metric =
                     62:                                   htonl(min(rt->rt_metric+1, HOPCNT_INFINITY));
                     63:                                toall(sendmsg);
                     64:                        }
                     65:                }
                     66:        }
                     67:        if (doinghost) {
                     68:                doinghost = 0;
                     69:                base = nethash;
                     70:                goto again;
                     71:        }
                     72:        if (timetobroadcast)
                     73:                toall(supply);
                     74:        alarm(TIMER_RATE);
                     75: }

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