140 lines
4.4 KiB
C
140 lines
4.4 KiB
C
/*
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* Copyright (c) 1985, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This file includes significant work done at Cornell University by
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* Bill Nesheim. That work included by permission.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)timer.c 8.1 (Berkeley) 6/5/93";
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#endif /* not lint */
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/*
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* Routing Table Management Daemon
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*/
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#include "defs.h"
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int timeval = -TIMER_RATE;
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/*
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* Timer routine. Performs routing information supply
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* duties and manages timers on routing table entries.
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*/
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void
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timer()
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{
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register struct rthash *rh;
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register struct rt_entry *rt;
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struct rthash *base = hosthash;
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int doinghost = 1, timetobroadcast;
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timeval += TIMER_RATE;
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if (lookforinterfaces && (timeval % CHECK_INTERVAL) == 0)
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ifinit();
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timetobroadcast = supplier && (timeval % SUPPLY_INTERVAL) == 0;
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again:
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for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) {
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rt = rh->rt_forw;
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for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
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/*
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* We don't advance time on a routing entry for
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* a passive gateway or that for our only interface.
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* The latter is excused because we don't act as
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* a routing information supplier and hence would
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* time it out. This is fair as if it's down
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* we're cut off from the world anyway and it's
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* not likely we'll grow any new hardware in
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* the mean time.
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*/
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if (!(rt->rt_state & RTS_PASSIVE) &&
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(supplier || !(rt->rt_state & RTS_INTERFACE)))
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rt->rt_timer += TIMER_RATE;
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if (rt->rt_timer >= EXPIRE_TIME)
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rt->rt_metric = HOPCNT_INFINITY;
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if (rt->rt_timer >= GARBAGE_TIME) {
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rt = rt->rt_back;
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/* Perhaps we should send a REQUEST for this route? */
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rtdelete(rt->rt_forw);
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continue;
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}
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if (rt->rt_state & RTS_CHANGED) {
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rt->rt_state &= ~RTS_CHANGED;
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/* don't send extraneous packets */
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if (!supplier || timetobroadcast)
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continue;
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msg->rip_cmd = htons(RIPCMD_RESPONSE);
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msg->rip_nets[0].rip_dst =
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(satons_addr(rt->rt_dst)).x_net;
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msg->rip_nets[0].rip_metric =
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htons(min(rt->rt_metric+1, HOPCNT_INFINITY));
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toall(sndmsg);
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}
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}
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}
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if (doinghost) {
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doinghost = 0;
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base = nethash;
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goto again;
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}
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if (timetobroadcast)
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toall(supply);
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alarm(TIMER_RATE);
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}
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/*
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* On hangup, let everyone know we're going away.
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*/
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void
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hup()
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{
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register struct rthash *rh;
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register struct rt_entry *rt;
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struct rthash *base = hosthash;
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int doinghost = 1;
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if (supplier) {
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again:
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for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) {
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rt = rh->rt_forw;
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for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw)
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rt->rt_metric = HOPCNT_INFINITY;
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}
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if (doinghost) {
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doinghost = 0;
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base = nethash;
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goto again;
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}
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toall(supply);
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}
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exit(1);
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}
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