| 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 5.3 (Berkeley) %G%"; |
| 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 | xnnet(msg->rip_nets[0].rip_dst[0]) = |
| 69 | ns_netof(satons_addr(rt->rt_dst)); |
| 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 | } |