1 /*
2 * Copyright (c) 1983, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)tables.c 8.1 (Berkeley) 6/5/93
30 * $FreeBSD: src/sbin/routed/table.c,v 1.9.2.2 2000/08/14 17:00:04 sheldonh Exp $
31 */
32
33 #include "defs.h"
34
35 static struct rt_spare *rts_better(struct rt_entry *);
36 static struct rt_spare rts_empty = {0,0,0,HOPCNT_INFINITY,0,0,0};
37 static void set_need_flash(void);
38 static void masktrim(struct sockaddr_in *ap);
39
40
41 struct radix_node_head *rhead; /* root of the radix tree */
42
43 int need_flash = 1; /* flash update needed
44 * start =1 to suppress the 1st
45 */
46
47 struct timeval age_timer; /* next check of old routes */
48 struct timeval need_kern = { /* need to update kernel table */
49 EPOCH+MIN_WAITTIME-1, 0
50 };
51
52 int stopint;
53
54 int total_routes;
55
56 /* zap any old routes through this gateway */
57 naddr age_bad_gate;
58
59
60 /* It is desirable to "aggregate" routes, to combine differing routes of
61 * the same metric and next hop into a common route with a smaller netmask
62 * or to suppress redundant routes, routes that add no information to
63 * routes with smaller netmasks.
64 *
65 * A route is redundant if and only if any and all routes with smaller
66 * but matching netmasks and nets are the same. Since routes are
67 * kept sorted in the radix tree, redundant routes always come second.
68 *
69 * There are two kinds of aggregations. First, two routes of the same bit
70 * mask and differing only in the least significant bit of the network
71 * number can be combined into a single route with a coarser mask.
72 *
73 * Second, a route can be suppressed in favor of another route with a more
74 * coarse mask provided no incompatible routes with intermediate masks
75 * are present. The second kind of aggregation involves suppressing routes.
76 * A route must not be suppressed if an incompatible route exists with
77 * an intermediate mask, since the suppressed route would be covered
78 * by the intermediate.
79 *
80 * This code relies on the radix tree walk encountering routes
81 * sorted first by address, with the smallest address first.
82 */
83
84 struct ag_info ag_slots[NUM_AG_SLOTS], *ag_avail, *ag_corsest, *ag_finest;
85
86 /* #define DEBUG_AG */
87 #ifdef DEBUG_AG
88 #define CHECK_AG() {int acnt = 0; struct ag_info *cag; \
89 for (cag = ag_avail; cag != NULL; cag = cag->ag_fine) \
90 acnt++; \
91 for (cag = ag_corsest; cag != NULL; cag = cag->ag_fine) \
92 acnt++; \
93 if (acnt != NUM_AG_SLOTS) { \
94 fflush(stderr); \
95 abort(); \
96 } \
97 }
98 #else
99 #define CHECK_AG()
100 #endif
101
102
103 /* Output the contents of an aggregation table slot.
104 * This function must always be immediately followed with the deletion
105 * of the target slot.
106 */
107 static void
ag_out(struct ag_info * ag,void (* out)(struct ag_info *))108 ag_out(struct ag_info *ag,
109 void (*out)(struct ag_info *))
110 {
111 struct ag_info *ag_cors;
112 naddr bit;
113
114
115 /* Forget it if this route should not be output for split-horizon. */
116 if (ag->ag_state & AGS_SPLIT_HZ)
117 return;
118
119 /* If we output both the even and odd twins, then the immediate parent,
120 * if it is present, is redundant, unless the parent manages to
121 * aggregate into something coarser.
122 * On successive calls, this code detects the even and odd twins,
123 * and marks the parent.
124 *
125 * Note that the order in which the radix tree code emits routes
126 * ensures that the twins are seen before the parent is emitted.
127 */
128 ag_cors = ag->ag_cors;
129 if (ag_cors != NULL
130 && ag_cors->ag_mask == ag->ag_mask<<1
131 && ag_cors->ag_dst_h == (ag->ag_dst_h & ag_cors->ag_mask)) {
132 ag_cors->ag_state |= ((ag_cors->ag_dst_h == ag->ag_dst_h)
133 ? AGS_REDUN0
134 : AGS_REDUN1);
135 }
136
137 /* Skip it if this route is itself redundant.
138 *
139 * It is ok to change the contents of the slot here, since it is
140 * always deleted next.
141 */
142 if (ag->ag_state & AGS_REDUN0) {
143 if (ag->ag_state & AGS_REDUN1)
144 return; /* quit if fully redundant */
145 /* make it finer if it is half-redundant */
146 bit = (-ag->ag_mask) >> 1;
147 ag->ag_dst_h |= bit;
148 ag->ag_mask |= bit;
149
150 } else if (ag->ag_state & AGS_REDUN1) {
151 /* make it finer if it is half-redundant */
152 bit = (-ag->ag_mask) >> 1;
153 ag->ag_mask |= bit;
154 }
155 out(ag);
156 }
157
158
159 static void
ag_del(struct ag_info * ag)160 ag_del(struct ag_info *ag)
161 {
162 CHECK_AG();
163
164 if (ag->ag_cors == 0)
165 ag_corsest = ag->ag_fine;
166 else
167 ag->ag_cors->ag_fine = ag->ag_fine;
168
169 if (ag->ag_fine == 0)
170 ag_finest = ag->ag_cors;
171 else
172 ag->ag_fine->ag_cors = ag->ag_cors;
173
174 ag->ag_fine = ag_avail;
175 ag_avail = ag;
176
177 CHECK_AG();
178 }
179
180
181 /* Flush routes waiting for aggregation.
182 * This must not suppress a route unless it is known that among all
183 * routes with coarser masks that match it, the one with the longest
184 * mask is appropriate. This is ensured by scanning the routes
185 * in lexical order, and with the most restrictive mask first
186 * among routes to the same destination.
187 */
188 void
ag_flush(naddr lim_dst_h,naddr lim_mask,void (* out)(struct ag_info *))189 ag_flush(naddr lim_dst_h, /* flush routes to here */
190 naddr lim_mask, /* matching this mask */
191 void (*out)(struct ag_info *))
192 {
193 struct ag_info *ag, *ag_cors;
194 naddr dst_h;
195
196
197 for (ag = ag_finest;
198 ag != NULL && ag->ag_mask >= lim_mask;
199 ag = ag_cors) {
200 ag_cors = ag->ag_cors;
201
202 /* work on only the specified routes */
203 dst_h = ag->ag_dst_h;
204 if ((dst_h & lim_mask) != lim_dst_h)
205 continue;
206
207 if (!(ag->ag_state & AGS_SUPPRESS))
208 ag_out(ag, out);
209
210 else for ( ; ; ag_cors = ag_cors->ag_cors) {
211 /* Look for a route that can suppress the
212 * current route */
213 if (ag_cors == NULL) {
214 /* failed, so output it and look for
215 * another route to work on
216 */
217 ag_out(ag, out);
218 break;
219 }
220
221 if ((dst_h & ag_cors->ag_mask) == ag_cors->ag_dst_h) {
222 /* We found a route with a coarser mask that
223 * aggregates the current target.
224 *
225 * If it has a different next hop, it
226 * cannot replace the target, so output
227 * the target.
228 */
229 if (ag->ag_gate != ag_cors->ag_gate
230 && !(ag->ag_state & AGS_FINE_GATE)
231 && !(ag_cors->ag_state & AGS_CORS_GATE)) {
232 ag_out(ag, out);
233 break;
234 }
235
236 /* If the coarse route has a good enough
237 * metric, it suppresses the target.
238 * If the suppressed target was redundant,
239 * then mark the suppressor redundant.
240 */
241 if (ag_cors->ag_pref <= ag->ag_pref) {
242 if (ag_cors->ag_seqno > ag->ag_seqno)
243 ag_cors->ag_seqno = ag->ag_seqno;
244 if (AG_IS_REDUN(ag->ag_state)
245 && ag_cors->ag_mask==ag->ag_mask<<1) {
246 if (ag_cors->ag_dst_h == dst_h)
247 ag_cors->ag_state |= AGS_REDUN0;
248 else
249 ag_cors->ag_state |= AGS_REDUN1;
250 }
251 if (ag->ag_tag != ag_cors->ag_tag)
252 ag_cors->ag_tag = 0;
253 if (ag->ag_nhop != ag_cors->ag_nhop)
254 ag_cors->ag_nhop = 0;
255 break;
256 }
257 }
258 }
259
260 /* That route has either been output or suppressed */
261 ag_cors = ag->ag_cors;
262 ag_del(ag);
263 }
264
265 CHECK_AG();
266 }
267
268
269 /* Try to aggregate a route with previous routes.
270 */
271 void
ag_check(naddr dst,naddr mask,naddr gate,naddr nhop,char metric,char pref,u_int seqnum,u_short tag,u_short state,void (* out)(struct ag_info *))272 ag_check(naddr dst,
273 naddr mask,
274 naddr gate,
275 naddr nhop,
276 char metric,
277 char pref,
278 u_int seqnum,
279 u_short tag,
280 u_short state,
281 void (*out)(struct ag_info *)) /* output using this */
282 {
283 struct ag_info *ag, *nag, *ag_cors;
284 naddr xaddr;
285 int x;
286
287 dst = ntohl(dst);
288
289 /* Punt non-contiguous subnet masks.
290 *
291 * (X & -X) contains a single bit if and only if X is a power of 2.
292 * (X + (X & -X)) == 0 if and only if X is a power of 2.
293 */
294 if ((mask & -mask) + mask != 0) {
295 struct ag_info nc_ag;
296
297 nc_ag.ag_dst_h = dst;
298 nc_ag.ag_mask = mask;
299 nc_ag.ag_gate = gate;
300 nc_ag.ag_nhop = nhop;
301 nc_ag.ag_metric = metric;
302 nc_ag.ag_pref = pref;
303 nc_ag.ag_tag = tag;
304 nc_ag.ag_state = state;
305 nc_ag.ag_seqno = seqnum;
306 out(&nc_ag);
307 return;
308 }
309
310 /* Search for the right slot in the aggregation table.
311 */
312 ag_cors = NULL;
313 ag = ag_corsest;
314 while (ag != NULL) {
315 if (ag->ag_mask >= mask)
316 break;
317
318 /* Suppress old routes (i.e. combine with compatible routes
319 * with coarser masks) as we look for the right slot in the
320 * aggregation table for the new route.
321 * A route to an address less than the current destination
322 * will not be affected by the current route or any route
323 * seen hereafter. That means it is safe to suppress it.
324 * This check keeps poor routes (e.g. with large hop counts)
325 * from preventing suppression of finer routes.
326 */
327 if (ag_cors != NULL
328 && ag->ag_dst_h < dst
329 && (ag->ag_state & AGS_SUPPRESS)
330 && ag_cors->ag_pref <= ag->ag_pref
331 && (ag->ag_dst_h & ag_cors->ag_mask) == ag_cors->ag_dst_h
332 && (ag_cors->ag_gate == ag->ag_gate
333 || (ag->ag_state & AGS_FINE_GATE)
334 || (ag_cors->ag_state & AGS_CORS_GATE))) {
335 if (ag_cors->ag_seqno > ag->ag_seqno)
336 ag_cors->ag_seqno = ag->ag_seqno;
337 /* If the suppressed target was redundant,
338 * then mark the suppressor redundant.
339 */
340 if (AG_IS_REDUN(ag->ag_state)
341 && ag_cors->ag_mask == ag->ag_mask<<1) {
342 if (ag_cors->ag_dst_h == dst)
343 ag_cors->ag_state |= AGS_REDUN0;
344 else
345 ag_cors->ag_state |= AGS_REDUN1;
346 }
347 if (ag->ag_tag != ag_cors->ag_tag)
348 ag_cors->ag_tag = 0;
349 if (ag->ag_nhop != ag_cors->ag_nhop)
350 ag_cors->ag_nhop = 0;
351 ag_del(ag);
352 CHECK_AG();
353 } else {
354 ag_cors = ag;
355 }
356 ag = ag_cors->ag_fine;
357 }
358
359 /* If we find the even/odd twin of the new route, and if the
360 * masks and so forth are equal, we can aggregate them.
361 * We can probably promote one of the pair.
362 *
363 * Since the routes are encountered in lexical order,
364 * the new route must be odd. However, the second or later
365 * times around this loop, it could be the even twin promoted
366 * from the even/odd pair of twins of the finer route.
367 */
368 while (ag != NULL
369 && ag->ag_mask == mask
370 && ((ag->ag_dst_h ^ dst) & (mask<<1)) == 0) {
371
372 /* Here we know the target route and the route in the current
373 * slot have the same netmasks and differ by at most the
374 * last bit. They are either for the same destination, or
375 * for an even/odd pair of destinations.
376 */
377 if (ag->ag_dst_h == dst) {
378 /* We have two routes to the same destination.
379 * Routes are encountered in lexical order, so a
380 * route is never promoted until the parent route is
381 * already present. So we know that the new route is
382 * a promoted (or aggregated) pair and the route
383 * already in the slot is the explicit route.
384 *
385 * Prefer the best route if their metrics differ,
386 * or the aggregated one if not, following a sort
387 * of longest-match rule.
388 */
389 if (pref <= ag->ag_pref) {
390 ag->ag_gate = gate;
391 ag->ag_nhop = nhop;
392 ag->ag_tag = tag;
393 ag->ag_metric = metric;
394 ag->ag_pref = pref;
395 x = ag->ag_state;
396 ag->ag_state = state;
397 state = x;
398 }
399
400 /* The sequence number controls flash updating,
401 * and should be the smaller of the two.
402 */
403 if (ag->ag_seqno > seqnum)
404 ag->ag_seqno = seqnum;
405
406 /* Some bits are set if they are set on either route,
407 * except when the route is for an interface.
408 */
409 if (!(ag->ag_state & AGS_IF))
410 ag->ag_state |= (state & (AGS_AGGREGATE_EITHER
411 | AGS_REDUN0
412 | AGS_REDUN1));
413 return;
414 }
415
416 /* If one of the routes can be promoted and the other can
417 * be suppressed, it may be possible to combine them or
418 * worthwhile to promote one.
419 *
420 * Any route that can be promoted is always
421 * marked to be eligible to be suppressed.
422 */
423 if (!((state & AGS_AGGREGATE)
424 && (ag->ag_state & AGS_SUPPRESS))
425 && !((ag->ag_state & AGS_AGGREGATE)
426 && (state & AGS_SUPPRESS)))
427 break;
428
429 /* A pair of even/odd twin routes can be combined
430 * if either is redundant, or if they are via the
431 * same gateway and have the same metric.
432 */
433 if (AG_IS_REDUN(ag->ag_state)
434 || AG_IS_REDUN(state)
435 || (ag->ag_gate == gate
436 && ag->ag_pref == pref
437 && (state & ag->ag_state & AGS_AGGREGATE) != 0)) {
438
439 /* We have both the even and odd pairs.
440 * Since the routes are encountered in order,
441 * the route in the slot must be the even twin.
442 *
443 * Combine and promote (aggregate) the pair of routes.
444 */
445 if (seqnum > ag->ag_seqno)
446 seqnum = ag->ag_seqno;
447 if (!AG_IS_REDUN(state))
448 state &= ~AGS_REDUN1;
449 if (AG_IS_REDUN(ag->ag_state))
450 state |= AGS_REDUN0;
451 else
452 state &= ~AGS_REDUN0;
453 state |= (ag->ag_state & AGS_AGGREGATE_EITHER);
454 if (ag->ag_tag != tag)
455 tag = 0;
456 if (ag->ag_nhop != nhop)
457 nhop = 0;
458
459 /* Get rid of the even twin that was already
460 * in the slot.
461 */
462 ag_del(ag);
463
464 } else if (ag->ag_pref >= pref
465 && (ag->ag_state & AGS_AGGREGATE)) {
466 /* If we cannot combine the pair, maybe the route
467 * with the worse metric can be promoted.
468 *
469 * Promote the old, even twin, by giving its slot
470 * in the table to the new, odd twin.
471 */
472 ag->ag_dst_h = dst;
473
474 xaddr = ag->ag_gate;
475 ag->ag_gate = gate;
476 gate = xaddr;
477
478 xaddr = ag->ag_nhop;
479 ag->ag_nhop = nhop;
480 nhop = xaddr;
481
482 x = ag->ag_tag;
483 ag->ag_tag = tag;
484 tag = x;
485
486 /* The promoted route is even-redundant only if the
487 * even twin was fully redundant. It is not
488 * odd-redundant because the odd-twin will still be
489 * in the table.
490 */
491 x = ag->ag_state;
492 if (!AG_IS_REDUN(x))
493 x &= ~AGS_REDUN0;
494 x &= ~AGS_REDUN1;
495 ag->ag_state = state;
496 state = x;
497
498 x = ag->ag_metric;
499 ag->ag_metric = metric;
500 metric = x;
501
502 x = ag->ag_pref;
503 ag->ag_pref = pref;
504 pref = x;
505
506 /* take the newest sequence number */
507 if (seqnum >= ag->ag_seqno)
508 seqnum = ag->ag_seqno;
509 else
510 ag->ag_seqno = seqnum;
511
512 } else {
513 if (!(state & AGS_AGGREGATE))
514 break; /* cannot promote either twin */
515
516 /* Promote the new, odd twin by shaving its
517 * mask and address.
518 * The promoted route is odd-redundant only if the
519 * odd twin was fully redundant. It is not
520 * even-redundant because the even twin is still in
521 * the table.
522 */
523 if (!AG_IS_REDUN(state))
524 state &= ~AGS_REDUN1;
525 state &= ~AGS_REDUN0;
526 if (seqnum > ag->ag_seqno)
527 seqnum = ag->ag_seqno;
528 else
529 ag->ag_seqno = seqnum;
530 }
531
532 mask <<= 1;
533 dst &= mask;
534
535 if (ag_cors == NULL) {
536 ag = ag_corsest;
537 break;
538 }
539 ag = ag_cors;
540 ag_cors = ag->ag_cors;
541 }
542
543 /* When we can no longer promote and combine routes,
544 * flush the old route in the target slot. Also flush
545 * any finer routes that we know will never be aggregated by
546 * the new route.
547 *
548 * In case we moved toward coarser masks,
549 * get back where we belong
550 */
551 if (ag != NULL
552 && ag->ag_mask < mask) {
553 ag_cors = ag;
554 ag = ag->ag_fine;
555 }
556
557 /* Empty the target slot
558 */
559 if (ag != NULL && ag->ag_mask == mask) {
560 ag_flush(ag->ag_dst_h, ag->ag_mask, out);
561 ag = (ag_cors == NULL) ? ag_corsest : ag_cors->ag_fine;
562 }
563
564 #ifdef DEBUG_AG
565 fflush(stderr);
566 if (ag == NULL && ag_cors != ag_finest)
567 abort();
568 if (ag_cors == NULL && ag != ag_corsest)
569 abort();
570 if (ag != NULL && ag->ag_cors != ag_cors)
571 abort();
572 if (ag_cors != NULL && ag_cors->ag_fine != ag)
573 abort();
574 CHECK_AG();
575 #endif
576
577 /* Save the new route on the end of the table.
578 */
579 nag = ag_avail;
580 ag_avail = nag->ag_fine;
581
582 nag->ag_dst_h = dst;
583 nag->ag_mask = mask;
584 nag->ag_gate = gate;
585 nag->ag_nhop = nhop;
586 nag->ag_metric = metric;
587 nag->ag_pref = pref;
588 nag->ag_tag = tag;
589 nag->ag_state = state;
590 nag->ag_seqno = seqnum;
591
592 nag->ag_fine = ag;
593 if (ag != NULL)
594 ag->ag_cors = nag;
595 else
596 ag_finest = nag;
597 nag->ag_cors = ag_cors;
598 if (ag_cors == NULL)
599 ag_corsest = nag;
600 else
601 ag_cors->ag_fine = nag;
602 CHECK_AG();
603 }
604
605
606 #define NAME0_LEN 14
607 static const char *
rtm_type_name(u_char type)608 rtm_type_name(u_char type)
609 {
610 static const char *rtm_types[] = {
611 "RTM_ADD",
612 "RTM_DELETE",
613 "RTM_CHANGE",
614 "RTM_GET",
615 "RTM_LOSING",
616 "RTM_REDIRECT",
617 "RTM_MISS",
618 "RTM_LOCK",
619 "unused 0x9",
620 "unused 0xa",
621 "RTM_RESOLVE",
622 "RTM_NEWADDR",
623 "RTM_DELADDR",
624 "RTM_IFINFO",
625 "RTM_NEWMADDR",
626 "RTM_DELMADDR"
627 };
628 #define NEW_RTM_PAT "RTM type %#x"
629 static char name0[sizeof(NEW_RTM_PAT)+2];
630
631
632 if (type > sizeof(rtm_types)/sizeof(rtm_types[0])
633 || type == 0) {
634 snprintf(name0, sizeof(name0), NEW_RTM_PAT, type);
635 return name0;
636 } else {
637 return rtm_types[type-1];
638 }
639 #undef NEW_RTM_PAT
640 }
641
642
643 /* Trim a mask in a sockaddr
644 * Produce a length of 0 for an address of 0.
645 * Otherwise produce the index of the first zero byte.
646 */
647 static void
masktrim(struct sockaddr_in * ap)648 masktrim(struct sockaddr_in *ap)
649 {
650 char *cp;
651
652 if (ap->sin_addr.s_addr == 0) {
653 ap->sin_len = 0;
654 return;
655 }
656 cp = (char *)(&ap->sin_addr.s_addr+1);
657 while (*--cp == 0)
658 continue;
659 ap->sin_len = cp - (char*)ap + 1;
660 }
661
662
663 /* Tell the kernel to add, delete or change a route
664 */
665 static void
rtioctl(int action,naddr dst,naddr gate,naddr mask,int metric,int flags)666 rtioctl(int action, /* RTM_DELETE, etc */
667 naddr dst,
668 naddr gate,
669 naddr mask,
670 int metric,
671 int flags)
672 {
673 struct {
674 struct rt_msghdr w_rtm;
675 struct sockaddr_in w_dst;
676 struct sockaddr_in w_gate;
677 struct sockaddr_in w_mask;
678 } w;
679 long cc;
680 # define PAT " %-10s %s metric=%d flags=%#x"
681 # define ARGS rtm_type_name(action), rtname(dst,mask,gate), metric, flags
682
683 again:
684 memset(&w, 0, sizeof(w));
685 w.w_rtm.rtm_msglen = sizeof(w);
686 w.w_rtm.rtm_version = RTM_VERSION;
687 w.w_rtm.rtm_type = action;
688 w.w_rtm.rtm_flags = flags;
689 w.w_rtm.rtm_seq = ++rt_sock_seqno;
690 w.w_rtm.rtm_addrs = RTA_DST|RTA_GATEWAY;
691 if (metric != 0 || action == RTM_CHANGE) {
692 w.w_rtm.rtm_rmx.rmx_hopcount = metric;
693 w.w_rtm.rtm_inits |= RTV_HOPCOUNT;
694 }
695 w.w_dst.sin_family = AF_INET;
696 w.w_dst.sin_addr.s_addr = dst;
697 w.w_gate.sin_family = AF_INET;
698 w.w_gate.sin_addr.s_addr = gate;
699 w.w_dst.sin_len = sizeof(w.w_dst);
700 w.w_gate.sin_len = sizeof(w.w_gate);
701 if (mask == HOST_MASK) {
702 w.w_rtm.rtm_flags |= RTF_HOST;
703 w.w_rtm.rtm_msglen -= sizeof(w.w_mask);
704 } else {
705 w.w_rtm.rtm_addrs |= RTA_NETMASK;
706 w.w_mask.sin_addr.s_addr = htonl(mask);
707 masktrim(&w.w_mask);
708 if (w.w_mask.sin_len == 0)
709 w.w_mask.sin_len = sizeof(long);
710 w.w_rtm.rtm_msglen -= (sizeof(w.w_mask) - w.w_mask.sin_len);
711 }
712
713 #ifndef NO_INSTALL
714 cc = write(rt_sock, &w, w.w_rtm.rtm_msglen);
715 if (cc < 0) {
716 if (errno == ESRCH
717 && (action == RTM_CHANGE || action == RTM_DELETE)) {
718 trace_act("route disappeared before" PAT, ARGS);
719 if (action == RTM_CHANGE) {
720 action = RTM_ADD;
721 goto again;
722 }
723 return;
724 }
725 msglog("write(rt_sock)" PAT ": %s", ARGS, strerror(errno));
726 return;
727 } else if (cc != w.w_rtm.rtm_msglen) {
728 msglog("write(rt_sock) wrote %ld instead of %d for" PAT,
729 cc, w.w_rtm.rtm_msglen, ARGS);
730 return;
731 }
732 #endif
733 if (TRACEKERNEL)
734 trace_misc("write kernel" PAT, ARGS);
735 #undef PAT
736 #undef ARGS
737 }
738
739
740 #define KHASH_SIZE 71 /* should be prime */
741 #define KHASH(a,m) khash_bins[((a) ^ (m)) % KHASH_SIZE]
742 static struct khash {
743 struct khash *k_next;
744 naddr k_dst;
745 naddr k_mask;
746 naddr k_gate;
747 short k_metric;
748 u_short k_state;
749 #define KS_NEW 0x001
750 #define KS_DELETE 0x002 /* need to delete the route */
751 #define KS_ADD 0x004 /* add to the kernel */
752 #define KS_CHANGE 0x008 /* tell kernel to change the route */
753 #define KS_DEL_ADD 0x010 /* delete & add to change the kernel */
754 #define KS_STATIC 0x020 /* Static flag in kernel */
755 #define KS_GATEWAY 0x040 /* G flag in kernel */
756 #define KS_DYNAMIC 0x080 /* result of redirect */
757 #define KS_DELETED 0x100 /* already deleted from kernel */
758 #define KS_CHECK 0x200
759 time_t k_keep;
760 #define K_KEEP_LIM 30
761 time_t k_redirect_time; /* when redirected route 1st seen */
762 } *khash_bins[KHASH_SIZE];
763
764
765 static struct khash*
kern_find(naddr dst,naddr mask,struct khash *** ppk)766 kern_find(naddr dst, naddr mask, struct khash ***ppk)
767 {
768 struct khash *k, **pk;
769
770 for (pk = &KHASH(dst,mask); (k = *pk) != NULL; pk = &k->k_next) {
771 if (k->k_dst == dst && k->k_mask == mask)
772 break;
773 }
774 if (ppk != NULL)
775 *ppk = pk;
776 return k;
777 }
778
779
780 static struct khash*
kern_add(naddr dst,naddr mask)781 kern_add(naddr dst, naddr mask)
782 {
783 struct khash *k, **pk;
784
785 k = kern_find(dst, mask, &pk);
786 if (k != NULL)
787 return k;
788
789 k = (struct khash *)rtmalloc(sizeof(*k), "kern_add");
790
791 memset(k, 0, sizeof(*k));
792 k->k_dst = dst;
793 k->k_mask = mask;
794 k->k_state = KS_NEW;
795 k->k_keep = now.tv_sec;
796 *pk = k;
797
798 return k;
799 }
800
801
802 /* If a kernel route has a non-zero metric, check that it is still in the
803 * daemon table, and not deleted by interfaces coming and going.
804 */
805 static void
kern_check_static(struct khash * k,struct interface * ifp)806 kern_check_static(struct khash *k,
807 struct interface *ifp)
808 {
809 struct rt_entry *rt;
810 struct rt_spare new;
811
812 if (k->k_metric == 0)
813 return;
814
815 memset(&new, 0, sizeof(new));
816 new.rts_ifp = ifp;
817 new.rts_gate = k->k_gate;
818 new.rts_router = (ifp != NULL) ? ifp->int_addr : loopaddr;
819 new.rts_metric = k->k_metric;
820 new.rts_time = now.tv_sec;
821
822 rt = rtget(k->k_dst, k->k_mask);
823 if (rt != NULL) {
824 if (!(rt->rt_state & RS_STATIC))
825 rtchange(rt, rt->rt_state | RS_STATIC, &new, 0);
826 } else {
827 rtadd(k->k_dst, k->k_mask, RS_STATIC, &new);
828 }
829 }
830
831
832 /* operate on a kernel entry
833 */
834 static void
kern_ioctl(struct khash * k,int action,int flags)835 kern_ioctl(struct khash *k,
836 int action, /* RTM_DELETE, etc */
837 int flags)
838
839 {
840 switch (action) {
841 case RTM_DELETE:
842 k->k_state &= ~KS_DYNAMIC;
843 if (k->k_state & KS_DELETED)
844 return;
845 k->k_state |= KS_DELETED;
846 break;
847 case RTM_ADD:
848 k->k_state &= ~KS_DELETED;
849 break;
850 case RTM_CHANGE:
851 if (k->k_state & KS_DELETED) {
852 action = RTM_ADD;
853 k->k_state &= ~KS_DELETED;
854 }
855 break;
856 }
857
858 rtioctl(action, k->k_dst, k->k_gate, k->k_mask, k->k_metric, flags);
859 }
860
861
862 /* add a route the kernel told us
863 */
864 static void
rtm_add(struct rt_msghdr * rtm,struct rt_addrinfo * info,time_t keep)865 rtm_add(struct rt_msghdr *rtm,
866 struct rt_addrinfo *info,
867 time_t keep)
868 {
869 struct khash *k;
870 struct interface *ifp;
871 naddr mask;
872
873
874 if (rtm->rtm_flags & RTF_HOST) {
875 mask = HOST_MASK;
876 } else if (INFO_MASK(info) != 0) {
877 mask = ntohl(S_ADDR(INFO_MASK(info)));
878 } else {
879 msglog("ignore %s without mask", rtm_type_name(rtm->rtm_type));
880 return;
881 }
882
883 k = kern_add(S_ADDR(INFO_DST(info)), mask);
884 if (k->k_state & KS_NEW)
885 k->k_keep = now.tv_sec+keep;
886 if (INFO_GATE(info) == 0) {
887 trace_act("note %s without gateway",
888 rtm_type_name(rtm->rtm_type));
889 k->k_metric = HOPCNT_INFINITY;
890 } else if (INFO_GATE(info)->sa_family != AF_INET) {
891 trace_act("note %s with gateway AF=%d",
892 rtm_type_name(rtm->rtm_type),
893 INFO_GATE(info)->sa_family);
894 k->k_metric = HOPCNT_INFINITY;
895 } else {
896 k->k_gate = S_ADDR(INFO_GATE(info));
897 k->k_metric = rtm->rtm_rmx.rmx_hopcount;
898 if (k->k_metric < 0)
899 k->k_metric = 0;
900 else if (k->k_metric > HOPCNT_INFINITY-1)
901 k->k_metric = HOPCNT_INFINITY-1;
902 }
903 k->k_state &= ~(KS_DELETE | KS_ADD | KS_CHANGE | KS_DEL_ADD
904 | KS_DELETED | KS_GATEWAY | KS_STATIC
905 | KS_NEW | KS_CHECK);
906 if (rtm->rtm_flags & RTF_GATEWAY)
907 k->k_state |= KS_GATEWAY;
908 if (rtm->rtm_flags & RTF_STATIC)
909 k->k_state |= KS_STATIC;
910
911 if (0 != (rtm->rtm_flags & (RTF_DYNAMIC | RTF_MODIFIED))) {
912 if (INFO_AUTHOR(info) != 0
913 && INFO_AUTHOR(info)->sa_family == AF_INET)
914 ifp = iflookup(S_ADDR(INFO_AUTHOR(info)));
915 else
916 ifp = NULL;
917 if (supplier
918 && (ifp == NULL || !(ifp->int_state & IS_REDIRECT_OK))) {
919 /* Routers are not supposed to listen to redirects,
920 * so delete it if it came via an unknown interface
921 * or the interface does not have special permission.
922 */
923 k->k_state &= ~KS_DYNAMIC;
924 k->k_state |= KS_DELETE;
925 LIM_SEC(need_kern, 0);
926 trace_act("mark for deletion redirected %s --> %s"
927 " via %s",
928 addrname(k->k_dst, k->k_mask, 0),
929 naddr_ntoa(k->k_gate),
930 ifp ? ifp->int_name : "unknown interface");
931 } else {
932 k->k_state |= KS_DYNAMIC;
933 k->k_redirect_time = now.tv_sec;
934 trace_act("accept redirected %s --> %s via %s",
935 addrname(k->k_dst, k->k_mask, 0),
936 naddr_ntoa(k->k_gate),
937 ifp ? ifp->int_name : "unknown interface");
938 }
939 return;
940 }
941
942 /* If it is not a static route, quit until the next comparison
943 * between the kernel and daemon tables, when it will be deleted.
944 */
945 if (!(k->k_state & KS_STATIC)) {
946 k->k_state |= KS_DELETE;
947 LIM_SEC(need_kern, k->k_keep);
948 return;
949 }
950
951 /* Put static routes with real metrics into the daemon table so
952 * they can be advertised.
953 *
954 * Find the interface toward the gateway.
955 */
956 ifp = iflookup(k->k_gate);
957 if (ifp == NULL)
958 msglog("static route %s --> %s impossibly lacks ifp",
959 addrname(S_ADDR(INFO_DST(info)), mask, 0),
960 naddr_ntoa(k->k_gate));
961
962 kern_check_static(k, ifp);
963 }
964
965
966 /* deal with packet loss
967 */
968 static void
rtm_lose(struct rt_msghdr * rtm,struct rt_addrinfo * info)969 rtm_lose(struct rt_msghdr *rtm,
970 struct rt_addrinfo *info)
971 {
972 if (INFO_GATE(info) == 0
973 || INFO_GATE(info)->sa_family != AF_INET) {
974 trace_act("ignore %s without gateway",
975 rtm_type_name(rtm->rtm_type));
976 return;
977 }
978
979 if (rdisc_ok)
980 rdisc_age(S_ADDR(INFO_GATE(info)));
981 age(S_ADDR(INFO_GATE(info)));
982 }
983
984
985 /* Make the gateway slot of an info structure point to something
986 * useful. If it is not already useful, but it specifies an interface,
987 * then fill in the sockaddr_in provided and point it there.
988 */
989 static int
get_info_gate(struct sockaddr ** sap,struct sockaddr_in * in)990 get_info_gate(struct sockaddr **sap,
991 struct sockaddr_in *in)
992 {
993 struct sockaddr_dl *sdl = (struct sockaddr_dl *)*sap;
994 struct interface *ifp;
995
996 if (sdl == NULL)
997 return 0;
998 if ((sdl)->sdl_family == AF_INET)
999 return 1;
1000 if ((sdl)->sdl_family != AF_LINK)
1001 return 0;
1002
1003 ifp = ifwithindex(sdl->sdl_index, 1);
1004 if (ifp == NULL)
1005 return 0;
1006
1007 in->sin_addr.s_addr = ifp->int_addr;
1008 in->sin_len = sizeof(*in);
1009 in->sin_family = AF_INET;
1010 *sap = (struct sockaddr *)in;
1011
1012 return 1;
1013 }
1014
1015
1016 /* Clean the kernel table by copying it to the daemon image.
1017 * Eventually the daemon will delete any extra routes.
1018 */
1019 void
flush_kern(void)1020 flush_kern(void)
1021 {
1022 static char *sysctl_buf;
1023 static size_t sysctl_buf_size = 0;
1024 size_t needed;
1025 int mib[6];
1026 char *next, *lim;
1027 struct rt_msghdr *rtm;
1028 struct sockaddr_in gate_sin;
1029 struct rt_addrinfo info;
1030 int i;
1031 struct khash *k;
1032
1033
1034 for (i = 0; i < KHASH_SIZE; i++) {
1035 for (k = khash_bins[i]; k != NULL; k = k->k_next) {
1036 k->k_state |= KS_CHECK;
1037 }
1038 }
1039
1040 mib[0] = CTL_NET;
1041 mib[1] = PF_ROUTE;
1042 mib[2] = 0; /* protocol */
1043 mib[3] = 0; /* wildcard address family */
1044 mib[4] = NET_RT_DUMP;
1045 mib[5] = 0; /* no flags */
1046 for (;;) {
1047 if ((needed = sysctl_buf_size) != 0) {
1048 if (sysctl(mib, 6, sysctl_buf,&needed, 0, 0) >= 0)
1049 break;
1050 if (errno != ENOMEM && errno != EFAULT)
1051 BADERR(1,"flush_kern: sysctl(RT_DUMP)");
1052 free(sysctl_buf);
1053 needed = 0;
1054 }
1055 if (sysctl(mib, 6, 0, &needed, 0, 0) < 0)
1056 BADERR(1,"flush_kern: sysctl(RT_DUMP) estimate");
1057 /* Kludge around the habit of some systems, such as
1058 * BSD/OS 3.1, to not admit how many routes are in the
1059 * kernel, or at least to be quite wrong.
1060 */
1061 needed += 50*(sizeof(*rtm)+5*sizeof(struct sockaddr));
1062 sysctl_buf = rtmalloc(sysctl_buf_size = needed,
1063 "flush_kern sysctl(RT_DUMP)");
1064 }
1065
1066 lim = sysctl_buf + needed;
1067 for (next = sysctl_buf; next < lim; next += rtm->rtm_msglen) {
1068 rtm = (struct rt_msghdr *)next;
1069 if (rtm->rtm_msglen == 0) {
1070 msglog("zero length kernel route at "
1071 " %#lx in buffer %#lx before %#lx",
1072 (u_long)rtm, (u_long)sysctl_buf, (u_long)lim);
1073 break;
1074 }
1075
1076 rt_xaddrs(&info,
1077 (struct sockaddr *)(rtm+1),
1078 (struct sockaddr *)(next + rtm->rtm_msglen),
1079 rtm->rtm_addrs);
1080
1081 if (INFO_DST(&info) == 0
1082 || INFO_DST(&info)->sa_family != AF_INET)
1083 continue;
1084
1085 /* ignore ARP table entries on systems with a merged route
1086 * and ARP table.
1087 */
1088 if (rtm->rtm_flags & RTF_LLINFO)
1089 continue;
1090
1091 /* ignore multicast addresses
1092 */
1093 if (IN_MULTICAST(ntohl(S_ADDR(INFO_DST(&info)))))
1094 continue;
1095
1096 if (!get_info_gate(&INFO_GATE(&info), &gate_sin))
1097 continue;
1098
1099 /* Note static routes and interface routes, and also
1100 * preload the image of the kernel table so that
1101 * we can later clean it, as well as avoid making
1102 * unneeded changes. Keep the old kernel routes for a
1103 * few seconds to allow a RIP or router-discovery
1104 * response to be heard.
1105 */
1106 rtm_add(rtm,&info,MIN_WAITTIME);
1107 }
1108
1109 for (i = 0; i < KHASH_SIZE; i++) {
1110 for (k = khash_bins[i]; k != NULL; k = k->k_next) {
1111 if (k->k_state & KS_CHECK) {
1112 msglog("%s --> %s disappeared from kernel",
1113 addrname(k->k_dst, k->k_mask, 0),
1114 naddr_ntoa(k->k_gate));
1115 del_static(k->k_dst, k->k_mask, k->k_gate, 1);
1116 }
1117 }
1118 }
1119 }
1120
1121
1122 /* Listen to announcements from the kernel
1123 */
1124 void
read_rt(void)1125 read_rt(void)
1126 {
1127 long cc;
1128 struct interface *ifp;
1129 struct sockaddr_in gate_sin;
1130 naddr mask, gate;
1131 union {
1132 struct {
1133 struct rt_msghdr rtm;
1134 struct sockaddr addrs[RTAX_MAX];
1135 } r;
1136 struct if_msghdr ifm;
1137 } m;
1138 char str[100], *strp;
1139 struct rt_addrinfo info;
1140
1141
1142 for (;;) {
1143 cc = read(rt_sock, &m, sizeof(m));
1144 if (cc <= 0) {
1145 if (cc < 0 && errno != EWOULDBLOCK)
1146 LOGERR("read(rt_sock)");
1147 return;
1148 }
1149
1150 if (m.r.rtm.rtm_version != RTM_VERSION) {
1151 msglog("bogus routing message version %d",
1152 m.r.rtm.rtm_version);
1153 continue;
1154 }
1155
1156 /* Ignore our own results.
1157 */
1158 if (m.r.rtm.rtm_type <= RTM_CHANGE
1159 && m.r.rtm.rtm_pid == mypid) {
1160 static int complained = 0;
1161 if (!complained) {
1162 msglog("receiving our own change messages");
1163 complained = 1;
1164 }
1165 continue;
1166 }
1167
1168 if (m.r.rtm.rtm_type == RTM_IFINFO
1169 || m.r.rtm.rtm_type == RTM_NEWADDR
1170 || m.r.rtm.rtm_type == RTM_DELADDR) {
1171 ifp = ifwithindex(m.ifm.ifm_index,
1172 m.r.rtm.rtm_type != RTM_DELADDR);
1173 if (ifp == NULL)
1174 trace_act("note %s with flags %#x"
1175 " for unknown interface index #%d",
1176 rtm_type_name(m.r.rtm.rtm_type),
1177 m.ifm.ifm_flags,
1178 m.ifm.ifm_index);
1179 else
1180 trace_act("note %s with flags %#x for %s",
1181 rtm_type_name(m.r.rtm.rtm_type),
1182 m.ifm.ifm_flags,
1183 ifp->int_name);
1184
1185 /* After being informed of a change to an interface,
1186 * check them all now if the check would otherwise
1187 * be a long time from now, if the interface is
1188 * not known, or if the interface has been turned
1189 * off or on.
1190 */
1191 if (ifinit_timer.tv_sec-now.tv_sec>=CHECK_BAD_INTERVAL
1192 || ifp == NULL
1193 || ((ifp->int_if_flags ^ m.ifm.ifm_flags)
1194 & IFF_UP) != 0)
1195 ifinit_timer.tv_sec = now.tv_sec;
1196 continue;
1197 }
1198
1199 strcpy(str, rtm_type_name(m.r.rtm.rtm_type));
1200 strp = &str[strlen(str)];
1201 if (m.r.rtm.rtm_type <= RTM_CHANGE)
1202 strp += sprintf(strp," from pid %d",m.r.rtm.rtm_pid);
1203
1204 rt_xaddrs(&info, m.r.addrs, &m.r.addrs[RTAX_MAX],
1205 m.r.rtm.rtm_addrs);
1206
1207 if (INFO_DST(&info) == 0) {
1208 trace_act("ignore %s without dst", str);
1209 continue;
1210 }
1211
1212 if (INFO_DST(&info)->sa_family != AF_INET) {
1213 trace_act("ignore %s for AF %d", str,
1214 INFO_DST(&info)->sa_family);
1215 continue;
1216 }
1217
1218 mask = ((INFO_MASK(&info) != 0)
1219 ? ntohl(S_ADDR(INFO_MASK(&info)))
1220 : (m.r.rtm.rtm_flags & RTF_HOST)
1221 ? HOST_MASK
1222 : std_mask(S_ADDR(INFO_DST(&info))));
1223
1224 strp += sprintf(strp, ": %s",
1225 addrname(S_ADDR(INFO_DST(&info)), mask, 0));
1226
1227 if (IN_MULTICAST(ntohl(S_ADDR(INFO_DST(&info))))) {
1228 trace_act("ignore multicast %s", str);
1229 continue;
1230 }
1231
1232 if (m.r.rtm.rtm_flags & RTF_LLINFO) {
1233 trace_act("ignore ARP %s", str);
1234 continue;
1235 }
1236
1237 if (get_info_gate(&INFO_GATE(&info), &gate_sin)) {
1238 gate = S_ADDR(INFO_GATE(&info));
1239 strp += sprintf(strp, " --> %s", naddr_ntoa(gate));
1240 } else {
1241 gate = 0;
1242 }
1243
1244 if (INFO_AUTHOR(&info) != 0)
1245 strp += sprintf(strp, " by authority of %s",
1246 saddr_ntoa(INFO_AUTHOR(&info)));
1247
1248 switch (m.r.rtm.rtm_type) {
1249 case RTM_ADD:
1250 case RTM_CHANGE:
1251 case RTM_REDIRECT:
1252 if (m.r.rtm.rtm_errno != 0) {
1253 trace_act("ignore %s with \"%s\" error",
1254 str, strerror(m.r.rtm.rtm_errno));
1255 } else {
1256 trace_act("%s", str);
1257 rtm_add(&m.r.rtm,&info,0);
1258 }
1259 break;
1260
1261 case RTM_DELETE:
1262 if (m.r.rtm.rtm_errno != 0
1263 && m.r.rtm.rtm_errno != ESRCH) {
1264 trace_act("ignore %s with \"%s\" error",
1265 str, strerror(m.r.rtm.rtm_errno));
1266 } else {
1267 trace_act("%s", str);
1268 del_static(S_ADDR(INFO_DST(&info)), mask,
1269 gate, 1);
1270 }
1271 break;
1272
1273 case RTM_LOSING:
1274 trace_act("%s", str);
1275 rtm_lose(&m.r.rtm,&info);
1276 break;
1277
1278 default:
1279 trace_act("ignore %s", str);
1280 break;
1281 }
1282 }
1283 }
1284
1285
1286 /* after aggregating, note routes that belong in the kernel
1287 */
1288 static void
kern_out(struct ag_info * ag)1289 kern_out(struct ag_info *ag)
1290 {
1291 struct khash *k;
1292
1293
1294 /* Do not install bad routes if they are not already present.
1295 * This includes routes that had RS_NET_SYN for interfaces that
1296 * recently died.
1297 */
1298 if (ag->ag_metric == HOPCNT_INFINITY) {
1299 k = kern_find(htonl(ag->ag_dst_h), ag->ag_mask, 0);
1300 if (k == NULL)
1301 return;
1302 } else {
1303 k = kern_add(htonl(ag->ag_dst_h), ag->ag_mask);
1304 }
1305
1306 if (k->k_state & KS_NEW) {
1307 /* will need to add new entry to the kernel table */
1308 k->k_state = KS_ADD;
1309 if (ag->ag_state & AGS_GATEWAY)
1310 k->k_state |= KS_GATEWAY;
1311 k->k_gate = ag->ag_gate;
1312 k->k_metric = ag->ag_metric;
1313 return;
1314 }
1315
1316 if (k->k_state & KS_STATIC)
1317 return;
1318
1319 /* modify existing kernel entry if necessary */
1320 if (k->k_gate != ag->ag_gate
1321 || k->k_metric != ag->ag_metric) {
1322 /* Must delete bad interface routes etc. to change them. */
1323 if (k->k_metric == HOPCNT_INFINITY)
1324 k->k_state |= KS_DEL_ADD;
1325 k->k_gate = ag->ag_gate;
1326 k->k_metric = ag->ag_metric;
1327 k->k_state |= KS_CHANGE;
1328 }
1329
1330 /* If the daemon thinks the route should exist, forget
1331 * about any redirections.
1332 * If the daemon thinks the route should exist, eventually
1333 * override manual intervention by the operator.
1334 */
1335 if ((k->k_state & (KS_DYNAMIC | KS_DELETED)) != 0) {
1336 k->k_state &= ~KS_DYNAMIC;
1337 k->k_state |= (KS_ADD | KS_DEL_ADD);
1338 }
1339
1340 if ((k->k_state & KS_GATEWAY)
1341 && !(ag->ag_state & AGS_GATEWAY)) {
1342 k->k_state &= ~KS_GATEWAY;
1343 k->k_state |= (KS_ADD | KS_DEL_ADD);
1344 } else if (!(k->k_state & KS_GATEWAY)
1345 && (ag->ag_state & AGS_GATEWAY)) {
1346 k->k_state |= KS_GATEWAY;
1347 k->k_state |= (KS_ADD | KS_DEL_ADD);
1348 }
1349
1350 /* Deleting-and-adding is necessary to change aspects of a route.
1351 * Just delete instead of deleting and then adding a bad route.
1352 * Otherwise, we want to keep the route in the kernel.
1353 */
1354 if (k->k_metric == HOPCNT_INFINITY
1355 && (k->k_state & KS_DEL_ADD))
1356 k->k_state |= KS_DELETE;
1357 else
1358 k->k_state &= ~KS_DELETE;
1359 #undef RT
1360 }
1361
1362
1363 static int
walk_kern(struct radix_node * rn,void * argp __unused)1364 walk_kern(struct radix_node *rn, void *argp __unused)
1365 {
1366 #define RT ((struct rt_entry *)rn)
1367 char metric, pref;
1368 u_int ags = 0;
1369
1370
1371 /* Do not install synthetic routes */
1372 if (RT->rt_state & RS_NET_SYN)
1373 return 0;
1374
1375 if (!(RT->rt_state & RS_IF)) {
1376 /* This is an ordinary route, not for an interface.
1377 */
1378
1379 /* aggregate, ordinary good routes without regard to
1380 * their metric
1381 */
1382 pref = 1;
1383 ags |= (AGS_GATEWAY | AGS_SUPPRESS | AGS_AGGREGATE);
1384
1385 /* Do not install host routes directly to hosts, to avoid
1386 * interfering with ARP entries in the kernel table.
1387 */
1388 if (RT_ISHOST(RT)
1389 && ntohl(RT->rt_dst) == RT->rt_gate)
1390 return 0;
1391
1392 } else {
1393 /* This is an interface route.
1394 * Do not install routes for "external" remote interfaces.
1395 */
1396 if (RT->rt_ifp != 0 && (RT->rt_ifp->int_state & IS_EXTERNAL))
1397 return 0;
1398
1399 /* Interfaces should override received routes.
1400 */
1401 pref = 0;
1402 ags |= (AGS_IF | AGS_CORS_GATE);
1403
1404 /* If it is not an interface, or an alias for an interface,
1405 * it must be a "gateway."
1406 *
1407 * If it is a "remote" interface, it is also a "gateway" to
1408 * the kernel if is not a alias.
1409 */
1410 if (RT->rt_ifp == 0
1411 || (RT->rt_ifp->int_state & IS_REMOTE))
1412 ags |= (AGS_GATEWAY | AGS_SUPPRESS | AGS_AGGREGATE);
1413 }
1414
1415 /* If RIP is off and IRDP is on, let the route to the discovered
1416 * route suppress any RIP routes. Eventually the RIP routes
1417 * will time-out and be deleted. This reaches the steady-state
1418 * quicker.
1419 */
1420 if ((RT->rt_state & RS_RDISC) && rip_sock < 0)
1421 ags |= AGS_CORS_GATE;
1422
1423 metric = RT->rt_metric;
1424 if (metric == HOPCNT_INFINITY) {
1425 /* if the route is dead, so try hard to aggregate. */
1426 pref = HOPCNT_INFINITY;
1427 ags |= (AGS_FINE_GATE | AGS_SUPPRESS);
1428 ags &= ~(AGS_IF | AGS_CORS_GATE);
1429 }
1430
1431 ag_check(RT->rt_dst, RT->rt_mask, RT->rt_gate, 0,
1432 metric,pref, 0, 0, ags, kern_out);
1433 return 0;
1434 #undef RT
1435 }
1436
1437
1438 /* Update the kernel table to match the daemon table.
1439 */
1440 static void
fix_kern(void)1441 fix_kern(void)
1442 {
1443 int i;
1444 struct khash *k, **pk;
1445
1446
1447 need_kern = age_timer;
1448
1449 /* Walk daemon table, updating the copy of the kernel table.
1450 */
1451 rhead->rnh_walktree(rhead, walk_kern, NULL);
1452 ag_flush(0, 0, kern_out);
1453
1454 for (i = 0; i < KHASH_SIZE; i++) {
1455 for (pk = &khash_bins[i]; (k = *pk) != NULL; ) {
1456 /* Do not touch static routes */
1457 if (k->k_state & KS_STATIC) {
1458 kern_check_static(k,0);
1459 pk = &k->k_next;
1460 continue;
1461 }
1462
1463 /* check hold on routes deleted by the operator */
1464 if (k->k_keep > now.tv_sec) {
1465 /* ensure we check when the hold is over */
1466 LIM_SEC(need_kern, k->k_keep);
1467 /* mark for the next cycle */
1468 k->k_state |= KS_DELETE;
1469 pk = &k->k_next;
1470 continue;
1471 }
1472
1473 if ((k->k_state & KS_DELETE)
1474 && !(k->k_state & KS_DYNAMIC)) {
1475 kern_ioctl(k, RTM_DELETE, 0);
1476 *pk = k->k_next;
1477 free(k);
1478 continue;
1479 }
1480
1481 if (k->k_state & KS_DEL_ADD)
1482 kern_ioctl(k, RTM_DELETE, 0);
1483
1484 if (k->k_state & KS_ADD) {
1485 kern_ioctl(k, RTM_ADD,
1486 ((0 != (k->k_state & (KS_GATEWAY
1487 | KS_DYNAMIC)))
1488 ? RTF_GATEWAY : 0));
1489 } else if (k->k_state & KS_CHANGE) {
1490 kern_ioctl(k, RTM_CHANGE,
1491 ((0 != (k->k_state & (KS_GATEWAY
1492 | KS_DYNAMIC)))
1493 ? RTF_GATEWAY : 0));
1494 }
1495 k->k_state &= ~(KS_ADD|KS_CHANGE|KS_DEL_ADD);
1496
1497 /* Mark this route to be deleted in the next cycle.
1498 * This deletes routes that disappear from the
1499 * daemon table, since the normal aging code
1500 * will clear the bit for routes that have not
1501 * disappeared from the daemon table.
1502 */
1503 k->k_state |= KS_DELETE;
1504 pk = &k->k_next;
1505 }
1506 }
1507 }
1508
1509
1510 /* Delete a static route in the image of the kernel table.
1511 */
1512 void
del_static(naddr dst,naddr mask,naddr gate,int gone)1513 del_static(naddr dst,
1514 naddr mask,
1515 naddr gate,
1516 int gone)
1517 {
1518 struct khash *k;
1519 struct rt_entry *rt;
1520
1521 /* Just mark it in the table to be deleted next time the kernel
1522 * table is updated.
1523 * If it has already been deleted, mark it as such, and set its
1524 * keep-timer so that it will not be deleted again for a while.
1525 * This lets the operator delete a route added by the daemon
1526 * and add a replacement.
1527 */
1528 k = kern_find(dst, mask, 0);
1529 if (k != NULL && (gate == 0 || k->k_gate == gate)) {
1530 k->k_state &= ~(KS_STATIC | KS_DYNAMIC | KS_CHECK);
1531 k->k_state |= KS_DELETE;
1532 if (gone) {
1533 k->k_state |= KS_DELETED;
1534 k->k_keep = now.tv_sec + K_KEEP_LIM;
1535 }
1536 }
1537
1538 rt = rtget(dst, mask);
1539 if (rt != NULL && (rt->rt_state & RS_STATIC))
1540 rtbad(rt);
1541 }
1542
1543
1544 /* Delete all routes generated from ICMP Redirects that use a given gateway,
1545 * as well as old redirected routes.
1546 */
1547 void
del_redirects(naddr bad_gate,time_t old)1548 del_redirects(naddr bad_gate,
1549 time_t old)
1550 {
1551 int i;
1552 struct khash *k;
1553
1554
1555 for (i = 0; i < KHASH_SIZE; i++) {
1556 for (k = khash_bins[i]; k != NULL; k = k->k_next) {
1557 if (!(k->k_state & KS_DYNAMIC)
1558 || (k->k_state & KS_STATIC))
1559 continue;
1560
1561 if (k->k_gate != bad_gate
1562 && k->k_redirect_time > old
1563 && !supplier)
1564 continue;
1565
1566 k->k_state |= KS_DELETE;
1567 k->k_state &= ~KS_DYNAMIC;
1568 need_kern.tv_sec = now.tv_sec;
1569 trace_act("mark redirected %s --> %s for deletion",
1570 addrname(k->k_dst, k->k_mask, 0),
1571 naddr_ntoa(k->k_gate));
1572 }
1573 }
1574 }
1575
1576
1577 /* Start the daemon tables.
1578 */
1579
1580 void
rtinit(void)1581 rtinit(void)
1582 {
1583 int i;
1584 struct ag_info *ag;
1585
1586 /* Initialize the radix trees */
1587 rn_init();
1588 rn_inithead(&rhead, rn_cpumaskhead(0),
1589 offsetof(struct sockaddr_in, sin_addr));
1590
1591 /* mark all of the slots in the table free */
1592 ag_avail = ag_slots;
1593 for (ag = ag_slots, i = 1; i < NUM_AG_SLOTS; i++) {
1594 ag->ag_fine = ag+1;
1595 ag++;
1596 }
1597 }
1598
1599
1600 static struct sockaddr_in dst_sock = {sizeof(dst_sock), AF_INET, 0, {0}, {0}};
1601 static struct sockaddr_in mask_sock = {sizeof(mask_sock), AF_INET, 0, {0}, {0}};
1602
1603
1604 static void
set_need_flash(void)1605 set_need_flash(void)
1606 {
1607 if (!need_flash) {
1608 need_flash = 1;
1609 /* Do not send the flash update immediately. Wait a little
1610 * while to hear from other routers.
1611 */
1612 no_flash.tv_sec = now.tv_sec + MIN_WAITTIME;
1613 }
1614 }
1615
1616
1617 /* Get a particular routing table entry
1618 */
1619 struct rt_entry *
rtget(naddr dst,naddr mask)1620 rtget(naddr dst, naddr mask)
1621 {
1622 struct rt_entry *rt;
1623
1624 dst_sock.sin_addr.s_addr = dst;
1625 mask_sock.sin_addr.s_addr = htonl(mask);
1626 masktrim(&mask_sock);
1627 rt = (struct rt_entry *)rhead->rnh_lookup(&dst_sock, &mask_sock, rhead);
1628 if (!rt || rt->rt_dst != dst || rt->rt_mask != mask)
1629 return 0;
1630
1631 return rt;
1632 }
1633
1634
1635 /* Find a route to dst as the kernel would.
1636 */
1637 struct rt_entry *
rtfind(naddr dst)1638 rtfind(naddr dst)
1639 {
1640 dst_sock.sin_addr.s_addr = dst;
1641 return (struct rt_entry *)rhead->rnh_matchaddr(&dst_sock, rhead);
1642 }
1643
1644
1645 /* add a route to the table
1646 */
1647 void
rtadd(naddr dst,naddr mask,u_int state,struct rt_spare * new)1648 rtadd(naddr dst,
1649 naddr mask,
1650 u_int state, /* rt_state for the entry */
1651 struct rt_spare *new)
1652 {
1653 struct rt_entry *rt;
1654 naddr smask;
1655 int i;
1656 struct rt_spare *rts;
1657
1658 rt = (struct rt_entry *)rtmalloc(sizeof (*rt), "rtadd");
1659 memset(rt, 0, sizeof(*rt));
1660 for (rts = rt->rt_spares, i = NUM_SPARES; i != 0; i--, rts++)
1661 rts->rts_metric = HOPCNT_INFINITY;
1662
1663 rt->rt_nodes->rn_key = (caddr_t)&rt->rt_dst_sock;
1664 rt->rt_dst = dst;
1665 rt->rt_dst_sock.sin_family = AF_INET;
1666 rt->rt_dst_sock.sin_len = dst_sock.sin_len;
1667 if (mask != HOST_MASK) {
1668 smask = std_mask(dst);
1669 if ((smask & ~mask) == 0 && mask > smask)
1670 state |= RS_SUBNET;
1671 }
1672 mask_sock.sin_addr.s_addr = htonl(mask);
1673 masktrim(&mask_sock);
1674 rt->rt_mask = mask;
1675 rt->rt_state = state;
1676 rt->rt_spares[0] = *new;
1677 rt->rt_time = now.tv_sec;
1678 rt->rt_poison_metric = HOPCNT_INFINITY;
1679 rt->rt_seqno = update_seqno;
1680
1681 if (++total_routes == MAX_ROUTES)
1682 msglog("have maximum (%d) routes", total_routes);
1683 if (TRACEACTIONS)
1684 trace_add_del("Add", rt);
1685
1686 need_kern.tv_sec = now.tv_sec;
1687 set_need_flash();
1688
1689 if (rhead->rnh_addaddr(&rt->rt_dst_sock, &mask_sock, rhead,
1690 rt->rt_nodes) == NULL) {
1691 msglog("rnh_addaddr() failed for %s mask=%#lx",
1692 naddr_ntoa(dst), (u_long)mask);
1693 free(rt);
1694 }
1695 }
1696
1697
1698 /* notice a changed route
1699 */
1700 void
rtchange(struct rt_entry * rt,u_int state,struct rt_spare * new,char * label)1701 rtchange(struct rt_entry *rt,
1702 u_int state, /* new state bits */
1703 struct rt_spare *new,
1704 char *label)
1705 {
1706 if (rt->rt_metric != new->rts_metric) {
1707 /* Fix the kernel immediately if it seems the route
1708 * has gone bad, since there may be a working route that
1709 * aggregates this route.
1710 */
1711 if (new->rts_metric == HOPCNT_INFINITY) {
1712 need_kern.tv_sec = now.tv_sec;
1713 if (new->rts_time >= now.tv_sec - EXPIRE_TIME)
1714 new->rts_time = now.tv_sec - EXPIRE_TIME;
1715 }
1716 rt->rt_seqno = update_seqno;
1717 set_need_flash();
1718 }
1719
1720 if (rt->rt_gate != new->rts_gate) {
1721 need_kern.tv_sec = now.tv_sec;
1722 rt->rt_seqno = update_seqno;
1723 set_need_flash();
1724 }
1725
1726 state |= (rt->rt_state & RS_SUBNET);
1727
1728 /* Keep various things from deciding ageless routes are stale.
1729 */
1730 if (!AGE_RT(state, new->rts_ifp))
1731 new->rts_time = now.tv_sec;
1732
1733 if (TRACEACTIONS)
1734 trace_change(rt, state, new,
1735 label ? label : "Chg ");
1736
1737 rt->rt_state = state;
1738 rt->rt_spares[0] = *new;
1739 }
1740
1741
1742 /* check for a better route among the spares
1743 */
1744 static struct rt_spare *
rts_better(struct rt_entry * rt)1745 rts_better(struct rt_entry *rt)
1746 {
1747 struct rt_spare *rts, *rts1;
1748 int i;
1749
1750 /* find the best alternative among the spares */
1751 rts = rt->rt_spares+1;
1752 for (i = NUM_SPARES, rts1 = rts+1; i > 2; i--, rts1++) {
1753 if (BETTER_LINK(rt,rts1,rts))
1754 rts = rts1;
1755 }
1756
1757 return rts;
1758 }
1759
1760
1761 /* switch to a backup route
1762 */
1763 void
rtswitch(struct rt_entry * rt,struct rt_spare * rts)1764 rtswitch(struct rt_entry *rt,
1765 struct rt_spare *rts)
1766 {
1767 struct rt_spare swap;
1768 char label[10];
1769
1770
1771 /* Do not change permanent routes */
1772 if (0 != (rt->rt_state & (RS_MHOME | RS_STATIC | RS_RDISC
1773 | RS_NET_SYN | RS_IF)))
1774 return;
1775
1776 /* find the best alternative among the spares */
1777 if (rts == NULL)
1778 rts = rts_better(rt);
1779
1780 /* Do not bother if it is not worthwhile.
1781 */
1782 if (!BETTER_LINK(rt, rts, rt->rt_spares))
1783 return;
1784
1785 swap = rt->rt_spares[0];
1786 sprintf(label, "Use #%d", (int)(rts - rt->rt_spares));
1787 rtchange(rt, rt->rt_state & ~(RS_NET_SYN | RS_RDISC), rts, label);
1788 if (swap.rts_metric == HOPCNT_INFINITY) {
1789 *rts = rts_empty;
1790 } else {
1791 *rts = swap;
1792 }
1793 }
1794
1795
1796 void
rtdelete(struct rt_entry * rt)1797 rtdelete(struct rt_entry *rt)
1798 {
1799 struct khash *k;
1800
1801
1802 if (TRACEACTIONS)
1803 trace_add_del("Del", rt);
1804
1805 k = kern_find(rt->rt_dst, rt->rt_mask, 0);
1806 if (k != NULL) {
1807 k->k_state |= KS_DELETE;
1808 need_kern.tv_sec = now.tv_sec;
1809 }
1810
1811 dst_sock.sin_addr.s_addr = rt->rt_dst;
1812 mask_sock.sin_addr.s_addr = htonl(rt->rt_mask);
1813 masktrim(&mask_sock);
1814 if (rt != (struct rt_entry *)rhead->rnh_deladdr(
1815 &dst_sock, &mask_sock, rhead)) {
1816 msglog("rnh_deladdr() failed");
1817 } else {
1818 free(rt);
1819 total_routes--;
1820 }
1821 }
1822
1823
1824 void
rts_delete(struct rt_entry * rt,struct rt_spare * rts)1825 rts_delete(struct rt_entry *rt,
1826 struct rt_spare *rts)
1827 {
1828 trace_upslot(rt, rts, &rts_empty);
1829 *rts = rts_empty;
1830 }
1831
1832
1833 /* Get rid of a bad route, and try to switch to a replacement.
1834 */
1835 void
rtbad(struct rt_entry * rt)1836 rtbad(struct rt_entry *rt)
1837 {
1838 struct rt_spare new;
1839
1840 /* Poison the route */
1841 new = rt->rt_spares[0];
1842 new.rts_metric = HOPCNT_INFINITY;
1843 rtchange(rt, rt->rt_state & ~(RS_IF | RS_LOCAL | RS_STATIC), &new, 0);
1844 rtswitch(rt, 0);
1845 }
1846
1847
1848 /* Junk a RS_NET_SYN or RS_LOCAL route,
1849 * unless it is needed by another interface.
1850 */
1851 void
rtbad_sub(struct rt_entry * rt)1852 rtbad_sub(struct rt_entry *rt)
1853 {
1854 struct interface *ifp, *ifp1;
1855 struct intnet *intnetp;
1856 u_int state;
1857
1858
1859 ifp1 = NULL;
1860 state = 0;
1861
1862 if (rt->rt_state & RS_LOCAL) {
1863 /* Is this the route through loopback for the interface?
1864 * If so, see if it is used by any other interfaces, such
1865 * as a point-to-point interface with the same local address.
1866 */
1867 for (ifp = ifnet; ifp != NULL; ifp = ifp->int_next) {
1868 /* Retain it if another interface needs it.
1869 */
1870 if (ifp->int_addr == rt->rt_ifp->int_addr) {
1871 state |= RS_LOCAL;
1872 ifp1 = ifp;
1873 break;
1874 }
1875 }
1876 }
1877
1878 if (!(state & RS_LOCAL)) {
1879 /* Retain RIPv1 logical network route if there is another
1880 * interface that justifies it.
1881 */
1882 if (rt->rt_state & RS_NET_SYN) {
1883 for (ifp = ifnet; ifp != NULL; ifp = ifp->int_next) {
1884 if ((ifp->int_state & IS_NEED_NET_SYN)
1885 && rt->rt_mask == ifp->int_std_mask
1886 && rt->rt_dst == ifp->int_std_addr) {
1887 state |= RS_NET_SYN;
1888 ifp1 = ifp;
1889 break;
1890 }
1891 }
1892 }
1893
1894 /* or if there is an authority route that needs it. */
1895 for (intnetp = intnets;
1896 intnetp != NULL;
1897 intnetp = intnetp->intnet_next) {
1898 if (intnetp->intnet_addr == rt->rt_dst
1899 && intnetp->intnet_mask == rt->rt_mask) {
1900 state |= (RS_NET_SYN | RS_NET_INT);
1901 break;
1902 }
1903 }
1904 }
1905
1906 if (ifp1 != NULL || (state & RS_NET_SYN)) {
1907 struct rt_spare new = rt->rt_spares[0];
1908 new.rts_ifp = ifp1;
1909 rtchange(rt, ((rt->rt_state & ~(RS_NET_SYN|RS_LOCAL)) | state),
1910 &new, 0);
1911 } else {
1912 rtbad(rt);
1913 }
1914 }
1915
1916
1917 /* Called while walking the table looking for sick interfaces
1918 * or after a time change.
1919 */
1920 int
walk_bad(struct radix_node * rn,void * argp __unused)1921 walk_bad(struct radix_node *rn, void *argp __unused)
1922 {
1923 #define RT ((struct rt_entry *)rn)
1924 struct rt_spare *rts;
1925 int i;
1926
1927
1928 /* fix any spare routes through the interface
1929 */
1930 rts = RT->rt_spares;
1931 for (i = NUM_SPARES; i != 1; i--) {
1932 rts++;
1933 if (rts->rts_metric < HOPCNT_INFINITY
1934 && (rts->rts_ifp == 0
1935 || (rts->rts_ifp->int_state & IS_BROKE)))
1936 rts_delete(RT, rts);
1937 }
1938
1939 /* Deal with the main route
1940 */
1941 /* finished if it has been handled before or if its interface is ok
1942 */
1943 if (RT->rt_ifp == 0 || !(RT->rt_ifp->int_state & IS_BROKE))
1944 return 0;
1945
1946 /* Bad routes for other than interfaces are easy.
1947 */
1948 if (0 == (RT->rt_state & (RS_IF | RS_NET_SYN | RS_LOCAL))) {
1949 rtbad(RT);
1950 return 0;
1951 }
1952
1953 rtbad_sub(RT);
1954 return 0;
1955 #undef RT
1956 }
1957
1958
1959 /* Check the age of an individual route.
1960 */
1961 static int
walk_age(struct radix_node * rn,void * argp __unused)1962 walk_age(struct radix_node *rn, void *argp __unused)
1963 {
1964 #define RT ((struct rt_entry *)rn)
1965 struct interface *ifp;
1966 struct rt_spare *rts;
1967 int i;
1968
1969
1970 /* age all of the spare routes, including the primary route
1971 * currently in use
1972 */
1973 rts = RT->rt_spares;
1974 for (i = NUM_SPARES; i != 0; i--, rts++) {
1975
1976 ifp = rts->rts_ifp;
1977 if (i == NUM_SPARES) {
1978 if (!AGE_RT(RT->rt_state, ifp)) {
1979 /* Keep various things from deciding ageless
1980 * routes are stale
1981 */
1982 rts->rts_time = now.tv_sec;
1983 continue;
1984 }
1985
1986 /* forget RIP routes after RIP has been turned off.
1987 */
1988 if (rip_sock < 0) {
1989 rtdelete(RT);
1990 return 0;
1991 }
1992 }
1993
1994 /* age failing routes
1995 */
1996 if (age_bad_gate == rts->rts_gate
1997 && rts->rts_time >= now_stale) {
1998 rts->rts_time -= SUPPLY_INTERVAL;
1999 }
2000
2001 /* trash the spare routes when they go bad */
2002 if (rts->rts_metric < HOPCNT_INFINITY
2003 && now_garbage > rts->rts_time
2004 && i != NUM_SPARES)
2005 rts_delete(RT, rts);
2006 }
2007
2008
2009 /* finished if the active route is still fresh */
2010 if (now_stale <= RT->rt_time)
2011 return 0;
2012
2013 /* try to switch to an alternative */
2014 rtswitch(RT, 0);
2015
2016 /* Delete a dead route after it has been publically mourned. */
2017 if (now_garbage > RT->rt_time) {
2018 rtdelete(RT);
2019 return 0;
2020 }
2021
2022 /* Start poisoning a bad route before deleting it. */
2023 if (now.tv_sec - RT->rt_time > EXPIRE_TIME) {
2024 struct rt_spare new = RT->rt_spares[0];
2025 new.rts_metric = HOPCNT_INFINITY;
2026 rtchange(RT, RT->rt_state, &new, 0);
2027 }
2028 return 0;
2029 }
2030
2031
2032 /* Watch for dead routes and interfaces.
2033 */
2034 void
age(naddr bad_gate)2035 age(naddr bad_gate)
2036 {
2037 struct interface *ifp;
2038 int need_query = 0;
2039
2040 /* If not listening to RIP, there is no need to age the routes in
2041 * the table.
2042 */
2043 age_timer.tv_sec = (now.tv_sec
2044 + ((rip_sock < 0) ? NEVER : SUPPLY_INTERVAL));
2045
2046 /* Check for dead IS_REMOTE interfaces by timing their
2047 * transmissions.
2048 */
2049 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
2050 if (!(ifp->int_state & IS_REMOTE))
2051 continue;
2052
2053 /* ignore unreachable remote interfaces */
2054 if (!check_remote(ifp))
2055 continue;
2056
2057 /* Restore remote interface that has become reachable
2058 */
2059 if (ifp->int_state & IS_BROKE)
2060 if_ok(ifp, "remote ");
2061
2062 if (ifp->int_act_time != NEVER
2063 && now.tv_sec - ifp->int_act_time > EXPIRE_TIME) {
2064 msglog("remote interface %s to %s timed out after"
2065 " %ld:%ld",
2066 ifp->int_name,
2067 naddr_ntoa(ifp->int_dstaddr),
2068 (now.tv_sec - ifp->int_act_time)/60,
2069 (now.tv_sec - ifp->int_act_time)%60);
2070 if_sick(ifp);
2071 }
2072
2073 /* If we have not heard from the other router
2074 * recently, ask it.
2075 */
2076 if (now.tv_sec >= ifp->int_query_time) {
2077 ifp->int_query_time = NEVER;
2078 need_query = 1;
2079 }
2080 }
2081
2082 /* Age routes. */
2083 age_bad_gate = bad_gate;
2084 rhead->rnh_walktree(rhead, walk_age, NULL);
2085
2086 /* delete old redirected routes to keep the kernel table small
2087 * and prevent blackholes
2088 */
2089 del_redirects(bad_gate, now.tv_sec-STALE_TIME);
2090
2091 /* Update the kernel routing table. */
2092 fix_kern();
2093
2094 /* poke reticent remote gateways */
2095 if (need_query)
2096 rip_query();
2097 }
2098