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Annotation of 43BSDReno/sbin/XNSrouted/timer.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1985 The Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * This file includes significant work done at Cornell University by
        !             6:  * Bill Nesheim.  That work included by permission.
        !             7:  *
        !             8:  * Redistribution and use in source and binary forms are permitted
        !             9:  * provided that: (1) source distributions retain this entire copyright
        !            10:  * notice and comment, and (2) distributions including binaries display
        !            11:  * the following acknowledgement:  ``This product includes software
        !            12:  * developed by the University of California, Berkeley and its contributors''
        !            13:  * in the documentation or other materials provided with the distribution
        !            14:  * and in all advertising materials mentioning features or use of this
        !            15:  * software. Neither the name of the University nor the names of its
        !            16:  * contributors may be used to endorse or promote products derived
        !            17:  * from this software without specific prior written permission.
        !            18:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            19:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            20:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            21:  */
        !            22: 
        !            23: #ifndef lint
        !            24: static char sccsid[] = "@(#)timer.c    5.6 (Berkeley) 6/1/90";
        !            25: #endif /* not lint */
        !            26: 
        !            27: /*
        !            28:  * Routing Table Management Daemon
        !            29:  */
        !            30: #include "defs.h"
        !            31: 
        !            32: int    timeval = -TIMER_RATE;
        !            33: 
        !            34: /*
        !            35:  * Timer routine.  Performs routing information supply
        !            36:  * duties and manages timers on routing table entries.
        !            37:  */
        !            38: timer()
        !            39: {
        !            40:        register struct rthash *rh;
        !            41:        register struct rt_entry *rt;
        !            42:        struct rthash *base = hosthash;
        !            43:        int doinghost = 1, timetobroadcast;
        !            44: 
        !            45:        timeval += TIMER_RATE;
        !            46:        if (lookforinterfaces && (timeval % CHECK_INTERVAL) == 0)
        !            47:                ifinit();
        !            48:        timetobroadcast = supplier && (timeval % SUPPLY_INTERVAL) == 0;
        !            49: again:
        !            50:        for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) {
        !            51:                rt = rh->rt_forw;
        !            52:                for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
        !            53:                        /*
        !            54:                         * We don't advance time on a routing entry for
        !            55:                         * a passive gateway or that for our only interface. 
        !            56:                         * The latter is excused because we don't act as
        !            57:                         * a routing information supplier and hence would
        !            58:                         * time it out.  This is fair as if it's down
        !            59:                         * we're cut off from the world anyway and it's
        !            60:                         * not likely we'll grow any new hardware in
        !            61:                         * the mean time.
        !            62:                         */
        !            63:                        if (!(rt->rt_state & RTS_PASSIVE) &&
        !            64:                            (supplier || !(rt->rt_state & RTS_INTERFACE)))
        !            65:                                rt->rt_timer += TIMER_RATE;
        !            66:                        if (rt->rt_timer >= EXPIRE_TIME)
        !            67:                                rt->rt_metric = HOPCNT_INFINITY;
        !            68:                        if (rt->rt_timer >= GARBAGE_TIME) {
        !            69:                                rt = rt->rt_back;
        !            70:                                /* Perhaps we should send a REQUEST for this route? */
        !            71:                                rtdelete(rt->rt_forw);
        !            72:                                continue;
        !            73:                        }
        !            74:                        if (rt->rt_state & RTS_CHANGED) {
        !            75:                                rt->rt_state &= ~RTS_CHANGED;
        !            76:                                /* don't send extraneous packets */
        !            77:                                if (!supplier || timetobroadcast)
        !            78:                                        continue;
        !            79:                                msg->rip_cmd = htons(RIPCMD_RESPONSE);
        !            80:                                msg->rip_nets[0].rip_dst =
        !            81:                                        (satons_addr(rt->rt_dst)).x_net;
        !            82:                                msg->rip_nets[0].rip_metric =
        !            83:                                        htons(min(rt->rt_metric+1, HOPCNT_INFINITY));
        !            84:                                toall(sendmsg);
        !            85:                        }
        !            86:                }
        !            87:        }
        !            88:        if (doinghost) {
        !            89:                doinghost = 0;
        !            90:                base = nethash;
        !            91:                goto again;
        !            92:        }
        !            93:        if (timetobroadcast)
        !            94:                toall(supply);
        !            95:        alarm(TIMER_RATE);
        !            96: }
        !            97: 
        !            98: /*
        !            99:  * On hangup, let everyone know we're going away.
        !           100:  */
        !           101: hup()
        !           102: {
        !           103:        register struct rthash *rh;
        !           104:        register struct rt_entry *rt;
        !           105:        struct rthash *base = hosthash;
        !           106:        int doinghost = 1;
        !           107: 
        !           108:        if (supplier) {
        !           109: again:
        !           110:                for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) {
        !           111:                        rt = rh->rt_forw;
        !           112:                        for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw)
        !           113:                                rt->rt_metric = HOPCNT_INFINITY;
        !           114:                }
        !           115:                if (doinghost) {
        !           116:                        doinghost = 0;
        !           117:                        base = nethash;
        !           118:                        goto again;
        !           119:                }
        !           120:                toall(supply);
        !           121:        }
        !           122:        exit(1);
        !           123: }

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