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18916298 RG |
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, with or without | |
9 | * modification, are permitted provided that the following conditions | |
10 | * are met: | |
11 | * 1. Redistributions of source code must retain the above copyright | |
12 | * notice, this list of conditions and the following disclaimer. | |
13 | * 2. Redistributions in binary form must reproduce the above copyright | |
14 | * notice, this list of conditions and the following disclaimer in the | |
15 | * documentation and/or other materials provided with the distribution. | |
16 | * 3. All advertising materials mentioning features or use of this software | |
17 | * must display the following acknowledgement: | |
18 | * This product includes software developed by the University of | |
19 | * California, Berkeley and its contributors. | |
20 | * 4. Neither the name of the University nor the names of its contributors | |
21 | * may be used to endorse or promote products derived from this software | |
22 | * without specific prior written permission. | |
23 | * | |
24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
34 | * SUCH DAMAGE. | |
35 | */ | |
36 | ||
37 | #ifndef lint | |
38 | static char sccsid[] = "@(#)timer.c 5.7 (Berkeley) 2/26/91"; | |
39 | #endif /* not lint */ | |
40 | ||
41 | /* | |
42 | * Routing Table Management Daemon | |
43 | */ | |
44 | #include "defs.h" | |
45 | ||
46 | int timeval = -TIMER_RATE; | |
47 | ||
48 | /* | |
49 | * Timer routine. Performs routing information supply | |
50 | * duties and manages timers on routing table entries. | |
51 | */ | |
52 | void | |
53 | timer() | |
54 | { | |
55 | register struct rthash *rh; | |
56 | register struct rt_entry *rt; | |
57 | struct rthash *base = hosthash; | |
58 | int doinghost = 1, timetobroadcast; | |
59 | ||
60 | timeval += TIMER_RATE; | |
61 | if (lookforinterfaces && (timeval % CHECK_INTERVAL) == 0) | |
62 | ifinit(); | |
63 | timetobroadcast = supplier && (timeval % SUPPLY_INTERVAL) == 0; | |
64 | again: | |
65 | for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) { | |
66 | rt = rh->rt_forw; | |
67 | for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw) { | |
68 | /* | |
69 | * We don't advance time on a routing entry for | |
70 | * a passive gateway or that for our only interface. | |
71 | * The latter is excused because we don't act as | |
72 | * a routing information supplier and hence would | |
73 | * time it out. This is fair as if it's down | |
74 | * we're cut off from the world anyway and it's | |
75 | * not likely we'll grow any new hardware in | |
76 | * the mean time. | |
77 | */ | |
78 | if (!(rt->rt_state & RTS_PASSIVE) && | |
79 | (supplier || !(rt->rt_state & RTS_INTERFACE))) | |
80 | rt->rt_timer += TIMER_RATE; | |
81 | if (rt->rt_timer >= EXPIRE_TIME) | |
82 | rt->rt_metric = HOPCNT_INFINITY; | |
83 | if (rt->rt_timer >= GARBAGE_TIME) { | |
84 | rt = rt->rt_back; | |
85 | /* Perhaps we should send a REQUEST for this route? */ | |
86 | rtdelete(rt->rt_forw); | |
87 | continue; | |
88 | } | |
89 | if (rt->rt_state & RTS_CHANGED) { | |
90 | rt->rt_state &= ~RTS_CHANGED; | |
91 | /* don't send extraneous packets */ | |
92 | if (!supplier || timetobroadcast) | |
93 | continue; | |
94 | msg->rip_cmd = htons(RIPCMD_RESPONSE); | |
95 | msg->rip_nets[0].rip_dst = | |
96 | (satons_addr(rt->rt_dst)).x_net; | |
97 | msg->rip_nets[0].rip_metric = | |
98 | htons(min(rt->rt_metric+1, HOPCNT_INFINITY)); | |
99 | toall(sndmsg); | |
100 | } | |
101 | } | |
102 | } | |
103 | if (doinghost) { | |
104 | doinghost = 0; | |
105 | base = nethash; | |
106 | goto again; | |
107 | } | |
108 | if (timetobroadcast) | |
109 | toall(supply); | |
110 | alarm(TIMER_RATE); | |
111 | } | |
112 | ||
113 | /* | |
114 | * On hangup, let everyone know we're going away. | |
115 | */ | |
116 | void | |
117 | hup() | |
118 | { | |
119 | register struct rthash *rh; | |
120 | register struct rt_entry *rt; | |
121 | struct rthash *base = hosthash; | |
122 | int doinghost = 1; | |
123 | ||
124 | if (supplier) { | |
125 | again: | |
126 | for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) { | |
127 | rt = rh->rt_forw; | |
128 | for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw) | |
129 | rt->rt_metric = HOPCNT_INFINITY; | |
130 | } | |
131 | if (doinghost) { | |
132 | doinghost = 0; | |
133 | base = nethash; | |
134 | goto again; | |
135 | } | |
136 | toall(supply); | |
137 | } | |
138 | exit(1); | |
139 | } |