xref: /freebsd/sbin/routed/table.c (revision dc318a4ffabcbfa23bb56a33403aad36e6de30af)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1983, 1988, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  * $FreeBSD$
32  */
33 
34 #include "defs.h"
35 
36 __RCSID("$FreeBSD$");
37 
38 static struct rt_spare *rts_better(struct rt_entry *);
39 static struct rt_spare rts_empty = {0,0,0,HOPCNT_INFINITY,0,0,0};
40 static void  set_need_flash(void);
41 #ifdef _HAVE_SIN_LEN
42 static void masktrim(struct sockaddr_in *ap);
43 #else
44 static void masktrim(struct sockaddr_in_new *ap);
45 #endif
46 static void rtbad(struct rt_entry *);
47 
48 
49 struct radix_node_head *rhead;		/* root of the radix tree */
50 
51 int	need_flash = 1;			/* flash update needed
52 					 * start =1 to suppress the 1st
53 					 */
54 
55 struct timeval age_timer;		/* next check of old routes */
56 struct timeval need_kern = {		/* need to update kernel table */
57 	EPOCH+MIN_WAITTIME-1, 0
58 };
59 
60 int	stopint;
61 
62 int	total_routes;
63 
64 /* zap any old routes through this gateway */
65 static naddr age_bad_gate;
66 
67 
68 /* It is desirable to "aggregate" routes, to combine differing routes of
69  * the same metric and next hop into a common route with a smaller netmask
70  * or to suppress redundant routes, routes that add no information to
71  * routes with smaller netmasks.
72  *
73  * A route is redundant if and only if any and all routes with smaller
74  * but matching netmasks and nets are the same.  Since routes are
75  * kept sorted in the radix tree, redundant routes always come second.
76  *
77  * There are two kinds of aggregations.  First, two routes of the same bit
78  * mask and differing only in the least significant bit of the network
79  * number can be combined into a single route with a coarser mask.
80  *
81  * Second, a route can be suppressed in favor of another route with a more
82  * coarse mask provided no incompatible routes with intermediate masks
83  * are present.  The second kind of aggregation involves suppressing routes.
84  * A route must not be suppressed if an incompatible route exists with
85  * an intermediate mask, since the suppressed route would be covered
86  * by the intermediate.
87  *
88  * This code relies on the radix tree walk encountering routes
89  * sorted first by address, with the smallest address first.
90  */
91 
92 static struct ag_info ag_slots[NUM_AG_SLOTS], *ag_avail, *ag_corsest, *ag_finest;
93 
94 /* #define DEBUG_AG */
95 #ifdef DEBUG_AG
96 #define CHECK_AG() {int acnt = 0; struct ag_info *cag;		\
97 	for (cag = ag_avail; cag != NULL; cag = cag->ag_fine)	\
98 		acnt++;						\
99 	for (cag = ag_corsest; cag != NULL; cag = cag->ag_fine)	\
100 		acnt++;						\
101 	if (acnt != NUM_AG_SLOTS) {				\
102 		(void)fflush(stderr);				\
103 		abort();					\
104 	}							\
105 }
106 #else
107 #define CHECK_AG()
108 #endif
109 
110 
111 /* Output the contents of an aggregation table slot.
112  *	This function must always be immediately followed with the deletion
113  *	of the target slot.
114  */
115 static void
116 ag_out(struct ag_info *ag,
117 	 void (*out)(struct ag_info *))
118 {
119 	struct ag_info *ag_cors;
120 	naddr bit;
121 
122 
123 	/* Forget it if this route should not be output for split-horizon. */
124 	if (ag->ag_state & AGS_SPLIT_HZ)
125 		return;
126 
127 	/* If we output both the even and odd twins, then the immediate parent,
128 	 * if it is present, is redundant, unless the parent manages to
129 	 * aggregate into something coarser.
130 	 * On successive calls, this code detects the even and odd twins,
131 	 * and marks the parent.
132 	 *
133 	 * Note that the order in which the radix tree code emits routes
134 	 * ensures that the twins are seen before the parent is emitted.
135 	 */
136 	ag_cors = ag->ag_cors;
137 	if (ag_cors != NULL
138 	    && ag_cors->ag_mask == ag->ag_mask<<1
139 	    && ag_cors->ag_dst_h == (ag->ag_dst_h & ag_cors->ag_mask)) {
140 		ag_cors->ag_state |= ((ag_cors->ag_dst_h == ag->ag_dst_h)
141 				      ? AGS_REDUN0
142 				      : AGS_REDUN1);
143 	}
144 
145 	/* Skip it if this route is itself redundant.
146 	 *
147 	 * It is ok to change the contents of the slot here, since it is
148 	 * always deleted next.
149 	 */
150 	if (ag->ag_state & AGS_REDUN0) {
151 		if (ag->ag_state & AGS_REDUN1)
152 			return;		/* quit if fully redundant */
153 		/* make it finer if it is half-redundant */
154 		bit = (-ag->ag_mask) >> 1;
155 		ag->ag_dst_h |= bit;
156 		ag->ag_mask |= bit;
157 
158 	} else if (ag->ag_state & AGS_REDUN1) {
159 		/* make it finer if it is half-redundant */
160 		bit = (-ag->ag_mask) >> 1;
161 		ag->ag_mask |= bit;
162 	}
163 	out(ag);
164 }
165 
166 
167 static void
168 ag_del(struct ag_info *ag)
169 {
170 	CHECK_AG();
171 
172 	if (ag->ag_cors == NULL)
173 		ag_corsest = ag->ag_fine;
174 	else
175 		ag->ag_cors->ag_fine = ag->ag_fine;
176 
177 	if (ag->ag_fine == NULL)
178 		ag_finest = ag->ag_cors;
179 	else
180 		ag->ag_fine->ag_cors = ag->ag_cors;
181 
182 	ag->ag_fine = ag_avail;
183 	ag_avail = ag;
184 
185 	CHECK_AG();
186 }
187 
188 
189 /* Flush routes waiting for aggregation.
190  *	This must not suppress a route unless it is known that among all
191  *	routes with coarser masks that match it, the one with the longest
192  *	mask is appropriate.  This is ensured by scanning the routes
193  *	in lexical order, and with the most restrictive mask first
194  *	among routes to the same destination.
195  */
196 void
197 ag_flush(naddr lim_dst_h,		/* flush routes to here */
198 	 naddr lim_mask,		/* matching this mask */
199 	 void (*out)(struct ag_info *))
200 {
201 	struct ag_info *ag, *ag_cors;
202 	naddr dst_h;
203 
204 
205 	for (ag = ag_finest;
206 	     ag != NULL && ag->ag_mask >= lim_mask;
207 	     ag = ag_cors) {
208 		ag_cors = ag->ag_cors;
209 
210 		/* work on only the specified routes */
211 		dst_h = ag->ag_dst_h;
212 		if ((dst_h & lim_mask) != lim_dst_h)
213 			continue;
214 
215 		if (!(ag->ag_state & AGS_SUPPRESS))
216 			ag_out(ag, out);
217 
218 		else for ( ; ; ag_cors = ag_cors->ag_cors) {
219 			/* Look for a route that can suppress the
220 			 * current route */
221 			if (ag_cors == NULL) {
222 				/* failed, so output it and look for
223 				 * another route to work on
224 				 */
225 				ag_out(ag, out);
226 				break;
227 			}
228 
229 			if ((dst_h & ag_cors->ag_mask) == ag_cors->ag_dst_h) {
230 				/* We found a route with a coarser mask that
231 				 * aggregates the current target.
232 				 *
233 				 * If it has a different next hop, it
234 				 * cannot replace the target, so output
235 				 * the target.
236 				 */
237 				if (ag->ag_gate != ag_cors->ag_gate
238 				    && !(ag->ag_state & AGS_FINE_GATE)
239 				    && !(ag_cors->ag_state & AGS_CORS_GATE)) {
240 					ag_out(ag, out);
241 					break;
242 				}
243 
244 				/* If the coarse route has a good enough
245 				 * metric, it suppresses the target.
246 				 * If the suppressed target was redundant,
247 				 * then mark the suppressor redundant.
248 				 */
249 				if (ag_cors->ag_pref <= ag->ag_pref) {
250 				    if (AG_IS_REDUN(ag->ag_state)
251 					&& ag_cors->ag_mask==ag->ag_mask<<1) {
252 					if (ag_cors->ag_dst_h == dst_h)
253 					    ag_cors->ag_state |= AGS_REDUN0;
254 					else
255 					    ag_cors->ag_state |= AGS_REDUN1;
256 				    }
257 				    if (ag->ag_tag != ag_cors->ag_tag)
258 					    ag_cors->ag_tag = 0;
259 				    if (ag->ag_nhop != ag_cors->ag_nhop)
260 					    ag_cors->ag_nhop = 0;
261 				    break;
262 				}
263 			}
264 		}
265 
266 		/* That route has either been output or suppressed */
267 		ag_cors = ag->ag_cors;
268 		ag_del(ag);
269 	}
270 
271 	CHECK_AG();
272 }
273 
274 
275 /* Try to aggregate a route with previous routes.
276  */
277 void
278 ag_check(naddr	dst,
279 	 naddr	mask,
280 	 naddr	gate,
281 	 naddr	nhop,
282 	 char	metric,
283 	 char	pref,
284 	 u_int	new_seqno,
285 	 u_short tag,
286 	 u_short state,
287 	 void (*out)(struct ag_info *))	/* output using this */
288 {
289 	struct ag_info *ag, *nag, *ag_cors;
290 	naddr xaddr;
291 	int x;
292 
293 	dst = ntohl(dst);
294 
295 	/* Punt non-contiguous subnet masks.
296 	 *
297 	 * (X & -X) contains a single bit if and only if X is a power of 2.
298 	 * (X + (X & -X)) == 0 if and only if X is a power of 2.
299 	 */
300 	if ((mask & -mask) + mask != 0) {
301 		struct ag_info nc_ag;
302 
303 		nc_ag.ag_dst_h = dst;
304 		nc_ag.ag_mask = mask;
305 		nc_ag.ag_gate = gate;
306 		nc_ag.ag_nhop = nhop;
307 		nc_ag.ag_metric = metric;
308 		nc_ag.ag_pref = pref;
309 		nc_ag.ag_tag = tag;
310 		nc_ag.ag_state = state;
311 		nc_ag.ag_seqno = new_seqno;
312 		out(&nc_ag);
313 		return;
314 	}
315 
316 	/* Search for the right slot in the aggregation table.
317 	 */
318 	ag_cors = NULL;
319 	ag = ag_corsest;
320 	while (ag != NULL) {
321 		if (ag->ag_mask >= mask)
322 			break;
323 
324 		/* Suppress old routes (i.e. combine with compatible routes
325 		 * with coarser masks) as we look for the right slot in the
326 		 * aggregation table for the new route.
327 		 * A route to an address less than the current destination
328 		 * will not be affected by the current route or any route
329 		 * seen hereafter.  That means it is safe to suppress it.
330 		 * This check keeps poor routes (e.g. with large hop counts)
331 		 * from preventing suppression of finer routes.
332 		 */
333 		if (ag_cors != NULL
334 		    && ag->ag_dst_h < dst
335 		    && (ag->ag_state & AGS_SUPPRESS)
336 		    && ag_cors->ag_pref <= ag->ag_pref
337 		    && (ag->ag_dst_h & ag_cors->ag_mask) == ag_cors->ag_dst_h
338 		    && (ag_cors->ag_gate == ag->ag_gate
339 			|| (ag->ag_state & AGS_FINE_GATE)
340 			|| (ag_cors->ag_state & AGS_CORS_GATE))) {
341 			/*  If the suppressed target was redundant,
342 			 * then mark the suppressor redundant.
343 			 */
344 			if (AG_IS_REDUN(ag->ag_state)
345 			    && ag_cors->ag_mask == ag->ag_mask<<1) {
346 				if (ag_cors->ag_dst_h == dst)
347 					ag_cors->ag_state |= AGS_REDUN0;
348 				else
349 					ag_cors->ag_state |= AGS_REDUN1;
350 			}
351 			if (ag->ag_tag != ag_cors->ag_tag)
352 				ag_cors->ag_tag = 0;
353 			if (ag->ag_nhop != ag_cors->ag_nhop)
354 				ag_cors->ag_nhop = 0;
355 			ag_del(ag);
356 			CHECK_AG();
357 		} else {
358 			ag_cors = ag;
359 		}
360 		ag = ag_cors->ag_fine;
361 	}
362 
363 	/* If we find the even/odd twin of the new route, and if the
364 	 * masks and so forth are equal, we can aggregate them.
365 	 * We can probably promote one of the pair.
366 	 *
367 	 * Since the routes are encountered in lexical order,
368 	 * the new route must be odd.  However, the second or later
369 	 * times around this loop, it could be the even twin promoted
370 	 * from the even/odd pair of twins of the finer route.
371 	 */
372 	while (ag != NULL
373 	       && ag->ag_mask == mask
374 	       && ((ag->ag_dst_h ^ dst) & (mask<<1)) == 0) {
375 
376 		/* Here we know the target route and the route in the current
377 		 * slot have the same netmasks and differ by at most the
378 		 * last bit.  They are either for the same destination, or
379 		 * for an even/odd pair of destinations.
380 		 */
381 		if (ag->ag_dst_h == dst) {
382 			/* We have two routes to the same destination.
383 			 * Routes are encountered in lexical order, so a
384 			 * route is never promoted until the parent route is
385 			 * already present.  So we know that the new route is
386 			 * a promoted (or aggregated) pair and the route
387 			 * already in the slot is the explicit route.
388 			 *
389 			 * Prefer the best route if their metrics differ,
390 			 * or the aggregated one if not, following a sort
391 			 * of longest-match rule.
392 			 */
393 			if (pref <= ag->ag_pref) {
394 				ag->ag_gate = gate;
395 				ag->ag_nhop = nhop;
396 				ag->ag_tag = tag;
397 				ag->ag_metric = metric;
398 				ag->ag_pref = pref;
399 				if (ag->ag_seqno < new_seqno)
400 					ag->ag_seqno = new_seqno;
401 				x = ag->ag_state;
402 				ag->ag_state = state;
403 				state = x;
404 			}
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 (new_seqno < ag->ag_seqno)
446 				new_seqno = 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 (new_seqno <= ag->ag_seqno)
508 				new_seqno = ag->ag_seqno;
509 			else
510 				ag->ag_seqno = new_seqno;
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 (new_seqno < ag->ag_seqno)
527 				new_seqno = ag->ag_seqno;
528 			else
529 				ag->ag_seqno = new_seqno;
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 	(void)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 = new_seqno;
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 static const char *
606 rtm_type_name(u_char type)
607 {
608 	static const char * const rtm_types[] = {
609 		"RTM_ADD",
610 		"RTM_DELETE",
611 		"RTM_CHANGE",
612 		"RTM_GET",
613 		"RTM_LOSING",
614 		"RTM_REDIRECT",
615 		"RTM_MISS",
616 		"RTM_LOCK",
617 		"RTM_OLDADD",
618 		"RTM_OLDDEL",
619 		"RTM_RESOLVE",
620 		"RTM_NEWADDR",
621 		"RTM_DELADDR",
622 #ifdef RTM_OIFINFO
623 		"RTM_OIFINFO",
624 #endif
625 		"RTM_IFINFO",
626 		"RTM_NEWMADDR",
627 		"RTM_DELMADDR"
628 	};
629 #define NEW_RTM_PAT "RTM type %#x"
630 	static char name0[sizeof(NEW_RTM_PAT)+2];
631 
632 
633 	if (type > sizeof(rtm_types)/sizeof(rtm_types[0])
634 	    || type == 0) {
635 		snprintf(name0, sizeof(name0), NEW_RTM_PAT, type);
636 		return name0;
637 	} else {
638 		return rtm_types[type-1];
639 	}
640 #undef NEW_RTM_PAT
641 }
642 
643 
644 /* Trim a mask in a sockaddr
645  *	Produce a length of 0 for an address of 0.
646  *	Otherwise produce the index of the first zero byte.
647  */
648 void
649 #ifdef _HAVE_SIN_LEN
650 masktrim(struct sockaddr_in *ap)
651 #else
652 masktrim(struct sockaddr_in_new *ap)
653 #endif
654 {
655 	char *cp;
656 
657 	if (ap->sin_addr.s_addr == 0) {
658 		ap->sin_len = 0;
659 		return;
660 	}
661 	cp = (char *)(&ap->sin_addr.s_addr+1);
662 	while (*--cp == 0)
663 		continue;
664 	ap->sin_len = cp - (char*)ap + 1;
665 }
666 
667 
668 /* Tell the kernel to add, delete or change a route
669  */
670 static void
671 rtioctl(int action,			/* RTM_DELETE, etc */
672 	naddr dst,
673 	naddr gate,
674 	naddr mask,
675 	int metric,
676 	int flags)
677 {
678 	struct {
679 		struct rt_msghdr w_rtm;
680 		struct sockaddr_in w_dst;
681 		struct sockaddr_in w_gate;
682 #ifdef _HAVE_SA_LEN
683 		struct sockaddr_in w_mask;
684 #else
685 		struct sockaddr_in_new w_mask;
686 #endif
687 	} w;
688 	long cc;
689 #   define PAT " %-10s %s metric=%d flags=%#x"
690 #   define ARGS rtm_type_name(action), rtname(dst,mask,gate), metric, flags
691 
692 again:
693 	memset(&w, 0, sizeof(w));
694 	w.w_rtm.rtm_msglen = sizeof(w);
695 	w.w_rtm.rtm_version = RTM_VERSION;
696 	w.w_rtm.rtm_type = action;
697 	w.w_rtm.rtm_flags = flags;
698 	w.w_rtm.rtm_seq = ++rt_sock_seqno;
699 	w.w_rtm.rtm_addrs = RTA_DST|RTA_GATEWAY;
700 	if (metric != 0 || action == RTM_CHANGE) {
701 		w.w_rtm.rtm_rmx.rmx_hopcount = metric;
702 		w.w_rtm.rtm_inits |= RTV_HOPCOUNT;
703 	}
704 	w.w_dst.sin_family = AF_INET;
705 	w.w_dst.sin_addr.s_addr = dst;
706 	w.w_gate.sin_family = AF_INET;
707 	w.w_gate.sin_addr.s_addr = gate;
708 #ifdef _HAVE_SA_LEN
709 	w.w_dst.sin_len = sizeof(w.w_dst);
710 	w.w_gate.sin_len = sizeof(w.w_gate);
711 #endif
712 	if (mask == HOST_MASK) {
713 		w.w_rtm.rtm_flags |= RTF_HOST;
714 		w.w_rtm.rtm_msglen -= sizeof(w.w_mask);
715 	} else {
716 		w.w_rtm.rtm_addrs |= RTA_NETMASK;
717 		w.w_mask.sin_addr.s_addr = htonl(mask);
718 #ifdef _HAVE_SA_LEN
719 		masktrim(&w.w_mask);
720 		if (w.w_mask.sin_len == 0)
721 			w.w_mask.sin_len = sizeof(long);
722 		w.w_rtm.rtm_msglen -= (sizeof(w.w_mask) - w.w_mask.sin_len);
723 #endif
724 	}
725 
726 #ifndef NO_INSTALL
727 	cc = write(rt_sock, &w, w.w_rtm.rtm_msglen);
728 	if (cc < 0) {
729 		if (errno == ESRCH
730 		    && (action == RTM_CHANGE || action == RTM_DELETE)) {
731 			trace_act("route disappeared before" PAT, ARGS);
732 			if (action == RTM_CHANGE) {
733 				action = RTM_ADD;
734 				goto again;
735 			}
736 			return;
737 		}
738 		msglog("write(rt_sock)" PAT ": %s", ARGS, strerror(errno));
739 		return;
740 	} else if (cc != w.w_rtm.rtm_msglen) {
741 		msglog("write(rt_sock) wrote %ld instead of %d for" PAT,
742 		       cc, w.w_rtm.rtm_msglen, ARGS);
743 		return;
744 	}
745 #endif
746 	if (TRACEKERNEL)
747 		trace_misc("write kernel" PAT, ARGS);
748 #undef PAT
749 #undef ARGS
750 }
751 
752 
753 #define KHASH_SIZE 71			/* should be prime */
754 #define KHASH(a,m) khash_bins[((a) ^ (m)) % KHASH_SIZE]
755 static struct khash {
756 	struct khash *k_next;
757 	naddr	k_dst;
758 	naddr	k_mask;
759 	naddr	k_gate;
760 	short	k_metric;
761 	u_short	k_state;
762 #define	    KS_NEW	0x001
763 #define	    KS_DELETE	0x002		/* need to delete the route */
764 #define	    KS_ADD	0x004		/* add to the kernel */
765 #define	    KS_CHANGE	0x008		/* tell kernel to change the route */
766 #define	    KS_DEL_ADD	0x010		/* delete & add to change the kernel */
767 #define	    KS_STATIC	0x020		/* Static flag in kernel */
768 #define	    KS_GATEWAY	0x040		/* G flag in kernel */
769 #define	    KS_DYNAMIC	0x080		/* result of redirect */
770 #define	    KS_DELETED	0x100		/* already deleted from kernel */
771 #define	    KS_CHECK	0x200
772 	time_t	k_keep;
773 #define	    K_KEEP_LIM	30
774 	time_t	k_redirect_time;	/* when redirected route 1st seen */
775 } *khash_bins[KHASH_SIZE];
776 
777 
778 static struct khash*
779 kern_find(naddr dst, naddr mask, struct khash ***ppk)
780 {
781 	struct khash *k, **pk;
782 
783 	for (pk = &KHASH(dst,mask); (k = *pk) != NULL; pk = &k->k_next) {
784 		if (k->k_dst == dst && k->k_mask == mask)
785 			break;
786 	}
787 	if (ppk != NULL)
788 		*ppk = pk;
789 	return k;
790 }
791 
792 
793 static struct khash*
794 kern_add(naddr dst, naddr mask)
795 {
796 	struct khash *k, **pk;
797 
798 	k = kern_find(dst, mask, &pk);
799 	if (k != NULL)
800 		return k;
801 
802 	k = (struct khash *)rtmalloc(sizeof(*k), "kern_add");
803 
804 	memset(k, 0, sizeof(*k));
805 	k->k_dst = dst;
806 	k->k_mask = mask;
807 	k->k_state = KS_NEW;
808 	k->k_keep = now.tv_sec;
809 	*pk = k;
810 
811 	return k;
812 }
813 
814 
815 /* If a kernel route has a non-zero metric, check that it is still in the
816  *	daemon table, and not deleted by interfaces coming and going.
817  */
818 static void
819 kern_check_static(struct khash *k,
820 		  struct interface *ifp)
821 {
822 	struct rt_entry *rt;
823 	struct rt_spare new;
824 
825 	if (k->k_metric == 0)
826 		return;
827 
828 	memset(&new, 0, sizeof(new));
829 	new.rts_ifp = ifp;
830 	new.rts_gate = k->k_gate;
831 	new.rts_router = (ifp != NULL) ? ifp->int_addr : loopaddr;
832 	new.rts_metric = k->k_metric;
833 	new.rts_time = now.tv_sec;
834 
835 	rt = rtget(k->k_dst, k->k_mask);
836 	if (rt != NULL) {
837 		if (!(rt->rt_state & RS_STATIC))
838 			rtchange(rt, rt->rt_state | RS_STATIC, &new, 0);
839 	} else {
840 		rtadd(k->k_dst, k->k_mask, RS_STATIC, &new);
841 	}
842 }
843 
844 
845 /* operate on a kernel entry
846  */
847 static void
848 kern_ioctl(struct khash *k,
849 	   int action,			/* RTM_DELETE, etc */
850 	   int flags)
851 
852 {
853 	switch (action) {
854 	case RTM_DELETE:
855 		k->k_state &= ~KS_DYNAMIC;
856 		if (k->k_state & KS_DELETED)
857 			return;
858 		k->k_state |= KS_DELETED;
859 		break;
860 	case RTM_ADD:
861 		k->k_state &= ~KS_DELETED;
862 		break;
863 	case RTM_CHANGE:
864 		if (k->k_state & KS_DELETED) {
865 			action = RTM_ADD;
866 			k->k_state &= ~KS_DELETED;
867 		}
868 		break;
869 	}
870 
871 	rtioctl(action, k->k_dst, k->k_gate, k->k_mask, k->k_metric, flags);
872 }
873 
874 
875 /* add a route the kernel told us
876  */
877 static void
878 rtm_add(struct rt_msghdr *rtm,
879 	struct rt_addrinfo *info,
880 	time_t keep)
881 {
882 	struct khash *k;
883 	struct interface *ifp;
884 	naddr mask;
885 
886 
887 	if (rtm->rtm_flags & RTF_HOST) {
888 		mask = HOST_MASK;
889 	} else if (INFO_MASK(info) != 0) {
890 		mask = ntohl(S_ADDR(INFO_MASK(info)));
891 	} else {
892 		msglog("ignore %s without mask", rtm_type_name(rtm->rtm_type));
893 		return;
894 	}
895 
896 	k = kern_add(S_ADDR(INFO_DST(info)), mask);
897 	if (k->k_state & KS_NEW)
898 		k->k_keep = now.tv_sec+keep;
899 	if (INFO_GATE(info) == 0) {
900 		trace_act("note %s without gateway",
901 			  rtm_type_name(rtm->rtm_type));
902 		k->k_metric = HOPCNT_INFINITY;
903 	} else if (INFO_GATE(info)->sa_family != AF_INET) {
904 		trace_act("note %s with gateway AF=%d",
905 			  rtm_type_name(rtm->rtm_type),
906 			  INFO_GATE(info)->sa_family);
907 		k->k_metric = HOPCNT_INFINITY;
908 	} else {
909 		k->k_gate = S_ADDR(INFO_GATE(info));
910 		k->k_metric = rtm->rtm_rmx.rmx_hopcount;
911 		if (k->k_metric < 0)
912 			k->k_metric = 0;
913 		else if (k->k_metric > HOPCNT_INFINITY-1)
914 			k->k_metric = HOPCNT_INFINITY-1;
915 	}
916 	k->k_state &= ~(KS_DELETE | KS_ADD | KS_CHANGE | KS_DEL_ADD
917 			| KS_DELETED | KS_GATEWAY | KS_STATIC
918 			| KS_NEW | KS_CHECK);
919 	if (rtm->rtm_flags & RTF_GATEWAY)
920 		k->k_state |= KS_GATEWAY;
921 	if (rtm->rtm_flags & RTF_STATIC)
922 		k->k_state |= KS_STATIC;
923 
924 	if (0 != (rtm->rtm_flags & (RTF_DYNAMIC | RTF_MODIFIED))) {
925 		if (INFO_AUTHOR(info) != 0
926 		    && INFO_AUTHOR(info)->sa_family == AF_INET)
927 			ifp = iflookup(S_ADDR(INFO_AUTHOR(info)));
928 		else
929 			ifp = NULL;
930 		if (supplier
931 		    && (ifp == NULL || !(ifp->int_state & IS_REDIRECT_OK))) {
932 			/* Routers are not supposed to listen to redirects,
933 			 * so delete it if it came via an unknown interface
934 			 * or the interface does not have special permission.
935 			 */
936 			k->k_state &= ~KS_DYNAMIC;
937 			k->k_state |= KS_DELETE;
938 			LIM_SEC(need_kern, 0);
939 			trace_act("mark for deletion redirected %s --> %s"
940 				  " via %s",
941 				  addrname(k->k_dst, k->k_mask, 0),
942 				  naddr_ntoa(k->k_gate),
943 				  ifp ? ifp->int_name : "unknown interface");
944 		} else {
945 			k->k_state |= KS_DYNAMIC;
946 			k->k_redirect_time = now.tv_sec;
947 			trace_act("accept redirected %s --> %s via %s",
948 				  addrname(k->k_dst, k->k_mask, 0),
949 				  naddr_ntoa(k->k_gate),
950 				  ifp ? ifp->int_name : "unknown interface");
951 		}
952 		return;
953 	}
954 
955 	/* If it is not a static route, quit until the next comparison
956 	 * between the kernel and daemon tables, when it will be deleted.
957 	 */
958 	if (!(k->k_state & KS_STATIC)) {
959 		k->k_state |= KS_DELETE;
960 		LIM_SEC(need_kern, k->k_keep);
961 		return;
962 	}
963 
964 	/* Put static routes with real metrics into the daemon table so
965 	 * they can be advertised.
966 	 *
967 	 * Find the interface toward the gateway.
968 	 */
969 	ifp = iflookup(k->k_gate);
970 	if (ifp == NULL)
971 		msglog("static route %s --> %s impossibly lacks ifp",
972 		       addrname(S_ADDR(INFO_DST(info)), mask, 0),
973 		       naddr_ntoa(k->k_gate));
974 
975 	kern_check_static(k, ifp);
976 }
977 
978 
979 /* deal with packet loss
980  */
981 static void
982 rtm_lose(struct rt_msghdr *rtm,
983 	 struct rt_addrinfo *info)
984 {
985 	if (INFO_GATE(info) == 0
986 	    || INFO_GATE(info)->sa_family != AF_INET) {
987 		trace_act("ignore %s without gateway",
988 			  rtm_type_name(rtm->rtm_type));
989 		return;
990 	}
991 
992 	if (rdisc_ok)
993 		rdisc_age(S_ADDR(INFO_GATE(info)));
994 	age(S_ADDR(INFO_GATE(info)));
995 }
996 
997 
998 /* Make the gateway slot of an info structure point to something
999  * useful.  If it is not already useful, but it specifies an interface,
1000  * then fill in the sockaddr_in provided and point it there.
1001  */
1002 static int
1003 get_info_gate(struct sockaddr **sap,
1004 	      struct sockaddr_in *rsin)
1005 {
1006 	struct sockaddr_dl *sdl = (struct sockaddr_dl *)*sap;
1007 	struct interface *ifp;
1008 
1009 	if (sdl == NULL)
1010 		return 0;
1011 	if ((sdl)->sdl_family == AF_INET)
1012 		return 1;
1013 	if ((sdl)->sdl_family != AF_LINK)
1014 		return 0;
1015 
1016 	ifp = ifwithindex(sdl->sdl_index, 1);
1017 	if (ifp == NULL)
1018 		return 0;
1019 
1020 	rsin->sin_addr.s_addr = ifp->int_addr;
1021 #ifdef _HAVE_SA_LEN
1022 	rsin->sin_len = sizeof(*rsin);
1023 #endif
1024 	rsin->sin_family = AF_INET;
1025 	*sap = (struct sockaddr*)rsin;
1026 
1027 	return 1;
1028 }
1029 
1030 
1031 /* Clean the kernel table by copying it to the daemon image.
1032  * Eventually the daemon will delete any extra routes.
1033  */
1034 void
1035 flush_kern(void)
1036 {
1037 	static char *sysctl_buf;
1038 	static size_t sysctl_buf_size = 0;
1039 	size_t needed;
1040 	int mib[6];
1041 	char *next, *lim;
1042 	struct rt_msghdr *rtm;
1043 	struct sockaddr_in gate_sin;
1044 	struct rt_addrinfo info;
1045 	int i;
1046 	struct khash *k;
1047 
1048 
1049 	for (i = 0; i < KHASH_SIZE; i++) {
1050 		for (k = khash_bins[i]; k != NULL; k = k->k_next) {
1051 			k->k_state |= KS_CHECK;
1052 		}
1053 	}
1054 
1055 	mib[0] = CTL_NET;
1056 	mib[1] = PF_ROUTE;
1057 	mib[2] = 0;		/* protocol */
1058 	mib[3] = 0;		/* wildcard address family */
1059 	mib[4] = NET_RT_DUMP;
1060 	mib[5] = 0;		/* no flags */
1061 	for (;;) {
1062 		if ((needed = sysctl_buf_size) != 0) {
1063 			if (sysctl(mib, 6, sysctl_buf,&needed, 0, 0) >= 0)
1064 				break;
1065 			if (errno != ENOMEM && errno != EFAULT)
1066 				BADERR(1,"flush_kern: sysctl(RT_DUMP)");
1067 			free(sysctl_buf);
1068 			needed = 0;
1069 		}
1070 		if (sysctl(mib, 6, 0, &needed, 0, 0) < 0)
1071 			BADERR(1,"flush_kern: sysctl(RT_DUMP) estimate");
1072 		/* Kludge around the habit of some systems, such as
1073 		 * BSD/OS 3.1, to not admit how many routes are in the
1074 		 * kernel, or at least to be quite wrong.
1075 		 */
1076 		needed += 50*(sizeof(*rtm)+5*sizeof(struct sockaddr));
1077 		sysctl_buf = rtmalloc(sysctl_buf_size = needed,
1078 				      "flush_kern sysctl(RT_DUMP)");
1079 	}
1080 
1081 	lim = sysctl_buf + needed;
1082 	for (next = sysctl_buf; next < lim; next += rtm->rtm_msglen) {
1083 		rtm = (struct rt_msghdr *)next;
1084 		if (rtm->rtm_msglen == 0) {
1085 			msglog("zero length kernel route at "
1086 			       " %#lx in buffer %#lx before %#lx",
1087 			       (u_long)rtm, (u_long)sysctl_buf, (u_long)lim);
1088 			break;
1089 		}
1090 
1091 		rt_xaddrs(&info,
1092 			  (struct sockaddr *)(rtm+1),
1093 			  (struct sockaddr *)(next + rtm->rtm_msglen),
1094 			  rtm->rtm_addrs);
1095 
1096 		if (INFO_DST(&info) == 0
1097 		    || INFO_DST(&info)->sa_family != AF_INET)
1098 			continue;
1099 
1100 #if defined (RTF_LLINFO)
1101 		/* ignore ARP table entries on systems with a merged route
1102 		 * and ARP table.
1103 		 */
1104 		if (rtm->rtm_flags & RTF_LLINFO)
1105 			continue;
1106 #endif
1107 #if defined(RTF_WASCLONED) && defined(__FreeBSD__)
1108 		/* ignore cloned routes
1109 		 */
1110 		if (rtm->rtm_flags & RTF_WASCLONED)
1111 			continue;
1112 #endif
1113 
1114 		/* ignore multicast addresses
1115 		 */
1116 		if (IN_MULTICAST(ntohl(S_ADDR(INFO_DST(&info)))))
1117 			continue;
1118 
1119 		if (!get_info_gate(&INFO_GATE(&info), &gate_sin))
1120 			continue;
1121 
1122 		/* Note static routes and interface routes, and also
1123 		 * preload the image of the kernel table so that
1124 		 * we can later clean it, as well as avoid making
1125 		 * unneeded changes.  Keep the old kernel routes for a
1126 		 * few seconds to allow a RIP or router-discovery
1127 		 * response to be heard.
1128 		 */
1129 		rtm_add(rtm,&info,MIN_WAITTIME);
1130 	}
1131 
1132 	for (i = 0; i < KHASH_SIZE; i++) {
1133 		for (k = khash_bins[i]; k != NULL; k = k->k_next) {
1134 			if (k->k_state & KS_CHECK) {
1135 				msglog("%s --> %s disappeared from kernel",
1136 				       addrname(k->k_dst, k->k_mask, 0),
1137 				       naddr_ntoa(k->k_gate));
1138 				del_static(k->k_dst, k->k_mask, k->k_gate, 1);
1139 			}
1140 		}
1141 	}
1142 }
1143 
1144 
1145 /* Listen to announcements from the kernel
1146  */
1147 void
1148 read_rt(void)
1149 {
1150 	long cc;
1151 	struct interface *ifp;
1152 	struct sockaddr_in gate_sin;
1153 	naddr mask, gate;
1154 	union {
1155 		struct {
1156 			struct rt_msghdr rtm;
1157 			struct sockaddr addrs[RTAX_MAX];
1158 		} r;
1159 		struct if_msghdr ifm;
1160 	} m;
1161 	char str[100], *strp;
1162 	struct rt_addrinfo info;
1163 
1164 
1165 	for (;;) {
1166 		cc = read(rt_sock, &m, sizeof(m));
1167 		if (cc <= 0) {
1168 			if (cc < 0 && errno != EWOULDBLOCK)
1169 				LOGERR("read(rt_sock)");
1170 			return;
1171 		}
1172 
1173 		if (m.r.rtm.rtm_version != RTM_VERSION) {
1174 			msglog("bogus routing message version %d",
1175 			       m.r.rtm.rtm_version);
1176 			continue;
1177 		}
1178 
1179 		/* Ignore our own results.
1180 		 */
1181 		if (m.r.rtm.rtm_type <= RTM_CHANGE
1182 		    && m.r.rtm.rtm_pid == mypid) {
1183 			static int complained = 0;
1184 			if (!complained) {
1185 				msglog("receiving our own change messages");
1186 				complained = 1;
1187 			}
1188 			continue;
1189 		}
1190 
1191 		if (m.r.rtm.rtm_type == RTM_IFINFO
1192 		    || m.r.rtm.rtm_type == RTM_NEWADDR
1193 		    || m.r.rtm.rtm_type == RTM_DELADDR) {
1194 			ifp = ifwithindex(m.ifm.ifm_index,
1195 					  m.r.rtm.rtm_type != RTM_DELADDR);
1196 			if (ifp == NULL)
1197 				trace_act("note %s with flags %#x"
1198 					  " for unknown interface index #%d",
1199 					  rtm_type_name(m.r.rtm.rtm_type),
1200 					  m.ifm.ifm_flags,
1201 					  m.ifm.ifm_index);
1202 			else
1203 				trace_act("note %s with flags %#x for %s",
1204 					  rtm_type_name(m.r.rtm.rtm_type),
1205 					  m.ifm.ifm_flags,
1206 					  ifp->int_name);
1207 
1208 			/* After being informed of a change to an interface,
1209 			 * check them all now if the check would otherwise
1210 			 * be a long time from now, if the interface is
1211 			 * not known, or if the interface has been turned
1212 			 * off or on.
1213 			 */
1214 			if (ifinit_timer.tv_sec-now.tv_sec>=CHECK_BAD_INTERVAL
1215 			    || ifp == NULL
1216 			    || ((ifp->int_if_flags ^ m.ifm.ifm_flags)
1217 				& IFF_UP) != 0)
1218 				ifinit_timer.tv_sec = now.tv_sec;
1219 			continue;
1220 		}
1221 #ifdef RTM_OIFINFO
1222 		if (m.r.rtm.rtm_type == RTM_OIFINFO)
1223 			continue;	/* ignore compat message */
1224 #endif
1225 
1226 		strlcpy(str, rtm_type_name(m.r.rtm.rtm_type), sizeof(str));
1227 		strp = &str[strlen(str)];
1228 		if (m.r.rtm.rtm_type <= RTM_CHANGE)
1229 			strp += sprintf(strp," from pid %d",m.r.rtm.rtm_pid);
1230 
1231 		/*
1232 		 * Only messages that use the struct rt_msghdr format are
1233 		 * allowed beyond this point.
1234 		 */
1235 		if (m.r.rtm.rtm_type > RTM_RESOLVE) {
1236 			trace_act("ignore %s", str);
1237 			continue;
1238 		}
1239 
1240 		rt_xaddrs(&info, m.r.addrs, &m.r.addrs[RTAX_MAX],
1241 			  m.r.rtm.rtm_addrs);
1242 
1243 		if (INFO_DST(&info) == 0) {
1244 			trace_act("ignore %s without dst", str);
1245 			continue;
1246 		}
1247 
1248 		if (INFO_DST(&info)->sa_family != AF_INET) {
1249 			trace_act("ignore %s for AF %d", str,
1250 				  INFO_DST(&info)->sa_family);
1251 			continue;
1252 		}
1253 
1254 		mask = ((INFO_MASK(&info) != 0)
1255 			? ntohl(S_ADDR(INFO_MASK(&info)))
1256 			: (m.r.rtm.rtm_flags & RTF_HOST)
1257 			? HOST_MASK
1258 			: std_mask(S_ADDR(INFO_DST(&info))));
1259 
1260 		strp += sprintf(strp, ": %s",
1261 				addrname(S_ADDR(INFO_DST(&info)), mask, 0));
1262 
1263 		if (IN_MULTICAST(ntohl(S_ADDR(INFO_DST(&info))))) {
1264 			trace_act("ignore multicast %s", str);
1265 			continue;
1266 		}
1267 
1268 #if defined(RTF_LLINFO)
1269 		if (m.r.rtm.rtm_flags & RTF_LLINFO) {
1270 			trace_act("ignore ARP %s", str);
1271 			continue;
1272 		}
1273 #endif
1274 
1275 #if defined(RTF_WASCLONED) && defined(__FreeBSD__)
1276 		if (m.r.rtm.rtm_flags & RTF_WASCLONED) {
1277 			trace_act("ignore cloned %s", str);
1278 			continue;
1279 		}
1280 #endif
1281 
1282 		if (get_info_gate(&INFO_GATE(&info), &gate_sin)) {
1283 			gate = S_ADDR(INFO_GATE(&info));
1284 			strp += sprintf(strp, " --> %s", naddr_ntoa(gate));
1285 		} else {
1286 			gate = 0;
1287 		}
1288 
1289 		if (INFO_AUTHOR(&info) != 0)
1290 			strp += sprintf(strp, " by authority of %s",
1291 					saddr_ntoa(INFO_AUTHOR(&info)));
1292 
1293 		switch (m.r.rtm.rtm_type) {
1294 		case RTM_ADD:
1295 		case RTM_CHANGE:
1296 		case RTM_REDIRECT:
1297 			if (m.r.rtm.rtm_errno != 0) {
1298 				trace_act("ignore %s with \"%s\" error",
1299 					  str, strerror(m.r.rtm.rtm_errno));
1300 			} else {
1301 				trace_act("%s", str);
1302 				rtm_add(&m.r.rtm,&info,0);
1303 			}
1304 			break;
1305 
1306 		case RTM_DELETE:
1307 			if (m.r.rtm.rtm_errno != 0
1308 			    && m.r.rtm.rtm_errno != ESRCH) {
1309 				trace_act("ignore %s with \"%s\" error",
1310 					  str, strerror(m.r.rtm.rtm_errno));
1311 			} else {
1312 				trace_act("%s", str);
1313 				del_static(S_ADDR(INFO_DST(&info)), mask,
1314 					   gate, 1);
1315 			}
1316 			break;
1317 
1318 		case RTM_LOSING:
1319 			trace_act("%s", str);
1320 			rtm_lose(&m.r.rtm,&info);
1321 			break;
1322 
1323 		default:
1324 			trace_act("ignore %s", str);
1325 			break;
1326 		}
1327 	}
1328 }
1329 
1330 
1331 /* after aggregating, note routes that belong in the kernel
1332  */
1333 static void
1334 kern_out(struct ag_info *ag)
1335 {
1336 	struct khash *k;
1337 
1338 
1339 	/* Do not install bad routes if they are not already present.
1340 	 * This includes routes that had RS_NET_SYN for interfaces that
1341 	 * recently died.
1342 	 */
1343 	if (ag->ag_metric == HOPCNT_INFINITY) {
1344 		k = kern_find(htonl(ag->ag_dst_h), ag->ag_mask, 0);
1345 		if (k == NULL)
1346 			return;
1347 	} else {
1348 		k = kern_add(htonl(ag->ag_dst_h), ag->ag_mask);
1349 	}
1350 
1351 	if (k->k_state & KS_NEW) {
1352 		/* will need to add new entry to the kernel table */
1353 		k->k_state = KS_ADD;
1354 		if (ag->ag_state & AGS_GATEWAY)
1355 			k->k_state |= KS_GATEWAY;
1356 		k->k_gate = ag->ag_gate;
1357 		k->k_metric = ag->ag_metric;
1358 		return;
1359 	}
1360 
1361 	if (k->k_state & KS_STATIC)
1362 		return;
1363 
1364 	/* modify existing kernel entry if necessary */
1365 	if (k->k_gate != ag->ag_gate
1366 	    || k->k_metric != ag->ag_metric) {
1367 		/* Must delete bad interface routes etc. to change them. */
1368 		if (k->k_metric == HOPCNT_INFINITY)
1369 			k->k_state |= KS_DEL_ADD;
1370 		k->k_gate = ag->ag_gate;
1371 		k->k_metric = ag->ag_metric;
1372 		k->k_state |= KS_CHANGE;
1373 	}
1374 
1375 	/* If the daemon thinks the route should exist, forget
1376 	 * about any redirections.
1377 	 * If the daemon thinks the route should exist, eventually
1378 	 * override manual intervention by the operator.
1379 	 */
1380 	if ((k->k_state & (KS_DYNAMIC | KS_DELETED)) != 0) {
1381 		k->k_state &= ~KS_DYNAMIC;
1382 		k->k_state |= (KS_ADD | KS_DEL_ADD);
1383 	}
1384 
1385 	if ((k->k_state & KS_GATEWAY)
1386 	    && !(ag->ag_state & AGS_GATEWAY)) {
1387 		k->k_state &= ~KS_GATEWAY;
1388 		k->k_state |= (KS_ADD | KS_DEL_ADD);
1389 	} else if (!(k->k_state & KS_GATEWAY)
1390 		   && (ag->ag_state & AGS_GATEWAY)) {
1391 		k->k_state |= KS_GATEWAY;
1392 		k->k_state |= (KS_ADD | KS_DEL_ADD);
1393 	}
1394 
1395 	/* Deleting-and-adding is necessary to change aspects of a route.
1396 	 * Just delete instead of deleting and then adding a bad route.
1397 	 * Otherwise, we want to keep the route in the kernel.
1398 	 */
1399 	if (k->k_metric == HOPCNT_INFINITY
1400 	    && (k->k_state & KS_DEL_ADD))
1401 		k->k_state |= KS_DELETE;
1402 	else
1403 		k->k_state &= ~KS_DELETE;
1404 #undef RT
1405 }
1406 
1407 
1408 /* ARGSUSED */
1409 static int
1410 walk_kern(struct radix_node *rn,
1411 	  struct walkarg *argp UNUSED)
1412 {
1413 #define RT ((struct rt_entry *)rn)
1414 	char metric, pref;
1415 	u_int ags = 0;
1416 
1417 
1418 	/* Do not install synthetic routes */
1419 	if (RT->rt_state & RS_NET_SYN)
1420 		return 0;
1421 
1422 	if (!(RT->rt_state & RS_IF)) {
1423 		/* This is an ordinary route, not for an interface.
1424 		 */
1425 
1426 		/* aggregate, ordinary good routes without regard to
1427 		 * their metric
1428 		 */
1429 		pref = 1;
1430 		ags |= (AGS_GATEWAY | AGS_SUPPRESS | AGS_AGGREGATE);
1431 
1432 		/* Do not install host routes directly to hosts, to avoid
1433 		 * interfering with ARP entries in the kernel table.
1434 		 */
1435 		if (RT_ISHOST(RT)
1436 		    && ntohl(RT->rt_dst) == RT->rt_gate)
1437 			return 0;
1438 
1439 	} else {
1440 		/* This is an interface route.
1441 		 * Do not install routes for "external" remote interfaces.
1442 		 */
1443 		if (RT->rt_ifp != 0 && (RT->rt_ifp->int_state & IS_EXTERNAL))
1444 			return 0;
1445 
1446 		/* Interfaces should override received routes.
1447 		 */
1448 		pref = 0;
1449 		ags |= (AGS_IF | AGS_CORS_GATE);
1450 
1451 		/* If it is not an interface, or an alias for an interface,
1452 		 * it must be a "gateway."
1453 		 *
1454 		 * If it is a "remote" interface, it is also a "gateway" to
1455 		 * the kernel if is not an alias.
1456 		 */
1457 		if (RT->rt_ifp == 0
1458 		    || (RT->rt_ifp->int_state & IS_REMOTE))
1459 			ags |= (AGS_GATEWAY | AGS_SUPPRESS | AGS_AGGREGATE);
1460 	}
1461 
1462 	/* If RIP is off and IRDP is on, let the route to the discovered
1463 	 * route suppress any RIP routes.  Eventually the RIP routes
1464 	 * will time-out and be deleted.  This reaches the steady-state
1465 	 * quicker.
1466 	 */
1467 	if ((RT->rt_state & RS_RDISC) && rip_sock < 0)
1468 		ags |= AGS_CORS_GATE;
1469 
1470 	metric = RT->rt_metric;
1471 	if (metric == HOPCNT_INFINITY) {
1472 		/* if the route is dead, so try hard to aggregate. */
1473 		pref = HOPCNT_INFINITY;
1474 		ags |= (AGS_FINE_GATE | AGS_SUPPRESS);
1475 		ags &= ~(AGS_IF | AGS_CORS_GATE);
1476 	}
1477 
1478 	ag_check(RT->rt_dst, RT->rt_mask, RT->rt_gate, 0,
1479 		 metric,pref, 0, 0, ags, kern_out);
1480 	return 0;
1481 #undef RT
1482 }
1483 
1484 
1485 /* Update the kernel table to match the daemon table.
1486  */
1487 static void
1488 fix_kern(void)
1489 {
1490 	int i;
1491 	struct khash *k, **pk;
1492 
1493 
1494 	need_kern = age_timer;
1495 
1496 	/* Walk daemon table, updating the copy of the kernel table.
1497 	 */
1498 	(void)rn_walktree(rhead, walk_kern, 0);
1499 	ag_flush(0,0,kern_out);
1500 
1501 	for (i = 0; i < KHASH_SIZE; i++) {
1502 		for (pk = &khash_bins[i]; (k = *pk) != NULL; ) {
1503 			/* Do not touch static routes */
1504 			if (k->k_state & KS_STATIC) {
1505 				kern_check_static(k,0);
1506 				pk = &k->k_next;
1507 				continue;
1508 			}
1509 
1510 			/* check hold on routes deleted by the operator */
1511 			if (k->k_keep > now.tv_sec) {
1512 				/* ensure we check when the hold is over */
1513 				LIM_SEC(need_kern, k->k_keep);
1514 				/* mark for the next cycle */
1515 				k->k_state |= KS_DELETE;
1516 				pk = &k->k_next;
1517 				continue;
1518 			}
1519 
1520 			if ((k->k_state & KS_DELETE)
1521 			    && !(k->k_state & KS_DYNAMIC)) {
1522 				kern_ioctl(k, RTM_DELETE, 0);
1523 				*pk = k->k_next;
1524 				free(k);
1525 				continue;
1526 			}
1527 
1528 			if (k->k_state & KS_DEL_ADD)
1529 				kern_ioctl(k, RTM_DELETE, 0);
1530 
1531 			if (k->k_state & KS_ADD) {
1532 				kern_ioctl(k, RTM_ADD,
1533 					   ((0 != (k->k_state & (KS_GATEWAY
1534 							| KS_DYNAMIC)))
1535 					    ? RTF_GATEWAY : 0));
1536 			} else if (k->k_state & KS_CHANGE) {
1537 				kern_ioctl(k,  RTM_CHANGE,
1538 					   ((0 != (k->k_state & (KS_GATEWAY
1539 							| KS_DYNAMIC)))
1540 					    ? RTF_GATEWAY : 0));
1541 			}
1542 			k->k_state &= ~(KS_ADD|KS_CHANGE|KS_DEL_ADD);
1543 
1544 			/* Mark this route to be deleted in the next cycle.
1545 			 * This deletes routes that disappear from the
1546 			 * daemon table, since the normal aging code
1547 			 * will clear the bit for routes that have not
1548 			 * disappeared from the daemon table.
1549 			 */
1550 			k->k_state |= KS_DELETE;
1551 			pk = &k->k_next;
1552 		}
1553 	}
1554 }
1555 
1556 
1557 /* Delete a static route in the image of the kernel table.
1558  */
1559 void
1560 del_static(naddr dst,
1561 	   naddr mask,
1562 	   naddr gate,
1563 	   int gone)
1564 {
1565 	struct khash *k;
1566 	struct rt_entry *rt;
1567 
1568 	/* Just mark it in the table to be deleted next time the kernel
1569 	 * table is updated.
1570 	 * If it has already been deleted, mark it as such, and set its
1571 	 * keep-timer so that it will not be deleted again for a while.
1572 	 * This lets the operator delete a route added by the daemon
1573 	 * and add a replacement.
1574 	 */
1575 	k = kern_find(dst, mask, 0);
1576 	if (k != NULL && (gate == 0 || k->k_gate == gate)) {
1577 		k->k_state &= ~(KS_STATIC | KS_DYNAMIC | KS_CHECK);
1578 		k->k_state |= KS_DELETE;
1579 		if (gone) {
1580 			k->k_state |= KS_DELETED;
1581 			k->k_keep = now.tv_sec + K_KEEP_LIM;
1582 		}
1583 	}
1584 
1585 	rt = rtget(dst, mask);
1586 	if (rt != NULL && (rt->rt_state & RS_STATIC))
1587 		rtbad(rt);
1588 }
1589 
1590 
1591 /* Delete all routes generated from ICMP Redirects that use a given gateway,
1592  * as well as old redirected routes.
1593  */
1594 void
1595 del_redirects(naddr bad_gate,
1596 	      time_t old)
1597 {
1598 	int i;
1599 	struct khash *k;
1600 
1601 
1602 	for (i = 0; i < KHASH_SIZE; i++) {
1603 		for (k = khash_bins[i]; k != NULL; k = k->k_next) {
1604 			if (!(k->k_state & KS_DYNAMIC)
1605 			    || (k->k_state & KS_STATIC))
1606 				continue;
1607 
1608 			if (k->k_gate != bad_gate
1609 			    && k->k_redirect_time > old
1610 			    && !supplier)
1611 				continue;
1612 
1613 			k->k_state |= KS_DELETE;
1614 			k->k_state &= ~KS_DYNAMIC;
1615 			need_kern.tv_sec = now.tv_sec;
1616 			trace_act("mark redirected %s --> %s for deletion",
1617 				  addrname(k->k_dst, k->k_mask, 0),
1618 				  naddr_ntoa(k->k_gate));
1619 		}
1620 	}
1621 }
1622 
1623 
1624 /* Start the daemon tables.
1625  */
1626 extern int max_keylen;
1627 
1628 void
1629 rtinit(void)
1630 {
1631 	int i;
1632 	struct ag_info *ag;
1633 
1634 	/* Initialize the radix trees */
1635 	max_keylen = sizeof(struct sockaddr_in);
1636 	rn_init();
1637 	rn_inithead(&rhead, 32);
1638 
1639 	/* mark all of the slots in the table free */
1640 	ag_avail = ag_slots;
1641 	for (ag = ag_slots, i = 1; i < NUM_AG_SLOTS; i++) {
1642 		ag->ag_fine = ag+1;
1643 		ag++;
1644 	}
1645 }
1646 
1647 
1648 #ifdef _HAVE_SIN_LEN
1649 static struct sockaddr_in dst_sock = {sizeof(dst_sock), AF_INET, 0, {0}, {0}};
1650 static struct sockaddr_in mask_sock = {sizeof(mask_sock), AF_INET, 0, {0}, {0}};
1651 #else
1652 static struct sockaddr_in_new dst_sock = {_SIN_ADDR_SIZE, AF_INET};
1653 static struct sockaddr_in_new mask_sock = {_SIN_ADDR_SIZE, AF_INET};
1654 #endif
1655 
1656 
1657 static void
1658 set_need_flash(void)
1659 {
1660 	if (!need_flash) {
1661 		need_flash = 1;
1662 		/* Do not send the flash update immediately.  Wait a little
1663 		 * while to hear from other routers.
1664 		 */
1665 		no_flash.tv_sec = now.tv_sec + MIN_WAITTIME;
1666 	}
1667 }
1668 
1669 
1670 /* Get a particular routing table entry
1671  */
1672 struct rt_entry *
1673 rtget(naddr dst, naddr mask)
1674 {
1675 	struct rt_entry *rt;
1676 
1677 	dst_sock.sin_addr.s_addr = dst;
1678 	mask_sock.sin_addr.s_addr = htonl(mask);
1679 	masktrim(&mask_sock);
1680 	rt = (struct rt_entry *)rhead->rnh_lookup(&dst_sock,&mask_sock,rhead);
1681 	if (!rt
1682 	    || rt->rt_dst != dst
1683 	    || rt->rt_mask != mask)
1684 		return 0;
1685 
1686 	return rt;
1687 }
1688 
1689 
1690 /* Find a route to dst as the kernel would.
1691  */
1692 struct rt_entry *
1693 rtfind(naddr dst)
1694 {
1695 	dst_sock.sin_addr.s_addr = dst;
1696 	return (struct rt_entry *)rhead->rnh_matchaddr(&dst_sock, rhead);
1697 }
1698 
1699 
1700 /* add a route to the table
1701  */
1702 void
1703 rtadd(naddr	dst,
1704       naddr	mask,
1705       u_int	state,			/* rt_state for the entry */
1706       struct	rt_spare *new)
1707 {
1708 	struct rt_entry *rt;
1709 	naddr smask;
1710 	int i;
1711 	struct rt_spare *rts;
1712 
1713 	rt = (struct rt_entry *)rtmalloc(sizeof (*rt), "rtadd");
1714 	memset(rt, 0, sizeof(*rt));
1715 	for (rts = rt->rt_spares, i = NUM_SPARES; i != 0; i--, rts++)
1716 		rts->rts_metric = HOPCNT_INFINITY;
1717 
1718 	rt->rt_nodes->rn_key = (caddr_t)&rt->rt_dst_sock;
1719 	rt->rt_dst = dst;
1720 	rt->rt_dst_sock.sin_family = AF_INET;
1721 #ifdef _HAVE_SIN_LEN
1722 	rt->rt_dst_sock.sin_len = dst_sock.sin_len;
1723 #endif
1724 	if (mask != HOST_MASK) {
1725 		smask = std_mask(dst);
1726 		if ((smask & ~mask) == 0 && mask > smask)
1727 			state |= RS_SUBNET;
1728 	}
1729 	mask_sock.sin_addr.s_addr = htonl(mask);
1730 	masktrim(&mask_sock);
1731 	rt->rt_mask = mask;
1732 	rt->rt_state = state;
1733 	rt->rt_spares[0] = *new;
1734 	rt->rt_time = now.tv_sec;
1735 	rt->rt_poison_metric = HOPCNT_INFINITY;
1736 	rt->rt_seqno = update_seqno;
1737 
1738 	if (++total_routes == MAX_ROUTES)
1739 		msglog("have maximum (%d) routes", total_routes);
1740 	if (TRACEACTIONS)
1741 		trace_add_del("Add", rt);
1742 
1743 	need_kern.tv_sec = now.tv_sec;
1744 	set_need_flash();
1745 
1746 	if (0 == rhead->rnh_addaddr(&rt->rt_dst_sock, &mask_sock,
1747 				    rhead, rt->rt_nodes)) {
1748 		msglog("rnh_addaddr() failed for %s mask=%#lx",
1749 		       naddr_ntoa(dst), (u_long)mask);
1750 		free(rt);
1751 	}
1752 }
1753 
1754 
1755 /* notice a changed route
1756  */
1757 void
1758 rtchange(struct rt_entry *rt,
1759 	 u_int	state,			/* new state bits */
1760 	 struct rt_spare *new,
1761 	 char	*label)
1762 {
1763 	if (rt->rt_metric != new->rts_metric) {
1764 		/* Fix the kernel immediately if it seems the route
1765 		 * has gone bad, since there may be a working route that
1766 		 * aggregates this route.
1767 		 */
1768 		if (new->rts_metric == HOPCNT_INFINITY) {
1769 			need_kern.tv_sec = now.tv_sec;
1770 			if (new->rts_time >= now.tv_sec - EXPIRE_TIME)
1771 				new->rts_time = now.tv_sec - EXPIRE_TIME;
1772 		}
1773 		rt->rt_seqno = update_seqno;
1774 		set_need_flash();
1775 	}
1776 
1777 	if (rt->rt_gate != new->rts_gate) {
1778 		need_kern.tv_sec = now.tv_sec;
1779 		rt->rt_seqno = update_seqno;
1780 		set_need_flash();
1781 	}
1782 
1783 	state |= (rt->rt_state & RS_SUBNET);
1784 
1785 	/* Keep various things from deciding ageless routes are stale.
1786 	 */
1787 	if (!AGE_RT(state, new->rts_ifp))
1788 		new->rts_time = now.tv_sec;
1789 
1790 	if (TRACEACTIONS)
1791 		trace_change(rt, state, new,
1792 			     label ? label : "Chg   ");
1793 
1794 	rt->rt_state = state;
1795 	rt->rt_spares[0] = *new;
1796 }
1797 
1798 
1799 /* check for a better route among the spares
1800  */
1801 static struct rt_spare *
1802 rts_better(struct rt_entry *rt)
1803 {
1804 	struct rt_spare *rts, *rts1;
1805 	int i;
1806 
1807 	/* find the best alternative among the spares */
1808 	rts = rt->rt_spares+1;
1809 	for (i = NUM_SPARES, rts1 = rts+1; i > 2; i--, rts1++) {
1810 		if (BETTER_LINK(rt,rts1,rts))
1811 			rts = rts1;
1812 	}
1813 
1814 	return rts;
1815 }
1816 
1817 
1818 /* switch to a backup route
1819  */
1820 void
1821 rtswitch(struct rt_entry *rt,
1822 	 struct rt_spare *rts)
1823 {
1824 	struct rt_spare swap;
1825 	char label[10];
1826 
1827 
1828 	/* Do not change permanent routes */
1829 	if (0 != (rt->rt_state & (RS_MHOME | RS_STATIC | RS_RDISC
1830 				  | RS_NET_SYN | RS_IF)))
1831 		return;
1832 
1833 	/* find the best alternative among the spares */
1834 	if (rts == NULL)
1835 		rts = rts_better(rt);
1836 
1837 	/* Do not bother if it is not worthwhile.
1838 	 */
1839 	if (!BETTER_LINK(rt, rts, rt->rt_spares))
1840 		return;
1841 
1842 	swap = rt->rt_spares[0];
1843 	(void)sprintf(label, "Use #%d", (int)(rts - rt->rt_spares));
1844 	rtchange(rt, rt->rt_state & ~(RS_NET_SYN | RS_RDISC), rts, label);
1845 	if (swap.rts_metric == HOPCNT_INFINITY) {
1846 		*rts = rts_empty;
1847 	} else {
1848 		*rts = swap;
1849 	}
1850 }
1851 
1852 
1853 void
1854 rtdelete(struct rt_entry *rt)
1855 {
1856 	struct khash *k;
1857 
1858 
1859 	if (TRACEACTIONS)
1860 		trace_add_del("Del", rt);
1861 
1862 	k = kern_find(rt->rt_dst, rt->rt_mask, 0);
1863 	if (k != NULL) {
1864 		k->k_state |= KS_DELETE;
1865 		need_kern.tv_sec = now.tv_sec;
1866 	}
1867 
1868 	dst_sock.sin_addr.s_addr = rt->rt_dst;
1869 	mask_sock.sin_addr.s_addr = htonl(rt->rt_mask);
1870 	masktrim(&mask_sock);
1871 	if (rt != (struct rt_entry *)rhead->rnh_deladdr(&dst_sock, &mask_sock,
1872 							rhead)) {
1873 		msglog("rnh_deladdr() failed");
1874 	} else {
1875 		free(rt);
1876 		total_routes--;
1877 	}
1878 }
1879 
1880 
1881 void
1882 rts_delete(struct rt_entry *rt,
1883 	   struct rt_spare *rts)
1884 {
1885 	trace_upslot(rt, rts, &rts_empty);
1886 	*rts = rts_empty;
1887 }
1888 
1889 
1890 /* Get rid of a bad route, and try to switch to a replacement.
1891  */
1892 static void
1893 rtbad(struct rt_entry *rt)
1894 {
1895 	struct rt_spare new;
1896 
1897 	/* Poison the route */
1898 	new = rt->rt_spares[0];
1899 	new.rts_metric = HOPCNT_INFINITY;
1900 	rtchange(rt, rt->rt_state & ~(RS_IF | RS_LOCAL | RS_STATIC), &new, 0);
1901 	rtswitch(rt, 0);
1902 }
1903 
1904 
1905 /* Junk a RS_NET_SYN or RS_LOCAL route,
1906  *	unless it is needed by another interface.
1907  */
1908 void
1909 rtbad_sub(struct rt_entry *rt)
1910 {
1911 	struct interface *ifp, *ifp1;
1912 	struct intnet *intnetp;
1913 	u_int state;
1914 
1915 
1916 	ifp1 = NULL;
1917 	state = 0;
1918 
1919 	if (rt->rt_state & RS_LOCAL) {
1920 		/* Is this the route through loopback for the interface?
1921 		 * If so, see if it is used by any other interfaces, such
1922 		 * as a point-to-point interface with the same local address.
1923 		 */
1924 		LIST_FOREACH(ifp, &ifnet, int_list) {
1925 			/* Retain it if another interface needs it.
1926 			 */
1927 			if (ifp->int_addr == rt->rt_ifp->int_addr) {
1928 				state |= RS_LOCAL;
1929 				ifp1 = ifp;
1930 				break;
1931 			}
1932 		}
1933 
1934 	}
1935 
1936 	if (!(state & RS_LOCAL)) {
1937 		/* Retain RIPv1 logical network route if there is another
1938 		 * interface that justifies it.
1939 		 */
1940 		if (rt->rt_state & RS_NET_SYN) {
1941 			LIST_FOREACH(ifp, &ifnet, int_list) {
1942 				if ((ifp->int_state & IS_NEED_NET_SYN)
1943 				    && rt->rt_mask == ifp->int_std_mask
1944 				    && rt->rt_dst == ifp->int_std_addr) {
1945 					state |= RS_NET_SYN;
1946 					ifp1 = ifp;
1947 					break;
1948 				}
1949 			}
1950 		}
1951 
1952 		/* or if there is an authority route that needs it. */
1953 		for (intnetp = intnets;
1954 		     intnetp != NULL;
1955 		     intnetp = intnetp->intnet_next) {
1956 			if (intnetp->intnet_addr == rt->rt_dst
1957 			    && intnetp->intnet_mask == rt->rt_mask) {
1958 				state |= (RS_NET_SYN | RS_NET_INT);
1959 				break;
1960 			}
1961 		}
1962 	}
1963 
1964 	if (ifp1 != NULL || (state & RS_NET_SYN)) {
1965 		struct rt_spare new = rt->rt_spares[0];
1966 		new.rts_ifp = ifp1;
1967 		rtchange(rt, ((rt->rt_state & ~(RS_NET_SYN|RS_LOCAL)) | state),
1968 			 &new, 0);
1969 	} else {
1970 		rtbad(rt);
1971 	}
1972 }
1973 
1974 
1975 /* Called while walking the table looking for sick interfaces
1976  * or after a time change.
1977  */
1978 /* ARGSUSED */
1979 int
1980 walk_bad(struct radix_node *rn,
1981 	 struct walkarg *argp UNUSED)
1982 {
1983 #define RT ((struct rt_entry *)rn)
1984 	struct rt_spare *rts;
1985 	int i;
1986 
1987 
1988 	/* fix any spare routes through the interface
1989 	 */
1990 	rts = RT->rt_spares;
1991 	for (i = NUM_SPARES; i != 1; i--) {
1992 		rts++;
1993 		if (rts->rts_metric < HOPCNT_INFINITY
1994 		    && (rts->rts_ifp == NULL
1995 			|| (rts->rts_ifp->int_state & IS_BROKE)))
1996 			rts_delete(RT, rts);
1997 	}
1998 
1999 	/* Deal with the main route
2000 	 */
2001 	/* finished if it has been handled before or if its interface is ok
2002 	 */
2003 	if (RT->rt_ifp == 0 || !(RT->rt_ifp->int_state & IS_BROKE))
2004 		return 0;
2005 
2006 	/* Bad routes for other than interfaces are easy.
2007 	 */
2008 	if (0 == (RT->rt_state & (RS_IF | RS_NET_SYN | RS_LOCAL))) {
2009 		rtbad(RT);
2010 		return 0;
2011 	}
2012 
2013 	rtbad_sub(RT);
2014 	return 0;
2015 #undef RT
2016 }
2017 
2018 
2019 /* Check the age of an individual route.
2020  */
2021 /* ARGSUSED */
2022 static int
2023 walk_age(struct radix_node *rn,
2024 	   struct walkarg *argp UNUSED)
2025 {
2026 #define RT ((struct rt_entry *)rn)
2027 	struct interface *ifp;
2028 	struct rt_spare *rts;
2029 	int i;
2030 
2031 
2032 	/* age all of the spare routes, including the primary route
2033 	 * currently in use
2034 	 */
2035 	rts = RT->rt_spares;
2036 	for (i = NUM_SPARES; i != 0; i--, rts++) {
2037 
2038 		ifp = rts->rts_ifp;
2039 		if (i == NUM_SPARES) {
2040 			if (!AGE_RT(RT->rt_state, ifp)) {
2041 				/* Keep various things from deciding ageless
2042 				 * routes are stale
2043 				 */
2044 				rts->rts_time = now.tv_sec;
2045 				continue;
2046 			}
2047 
2048 			/* forget RIP routes after RIP has been turned off.
2049 			 */
2050 			if (rip_sock < 0) {
2051 				rtdelete(RT);
2052 				return 0;
2053 			}
2054 		}
2055 
2056 		/* age failing routes
2057 		 */
2058 		if (age_bad_gate == rts->rts_gate
2059 		    && rts->rts_time >= now_stale) {
2060 			rts->rts_time -= SUPPLY_INTERVAL;
2061 		}
2062 
2063 		/* trash the spare routes when they go bad */
2064 		if (rts->rts_metric < HOPCNT_INFINITY
2065 		    && now_garbage > rts->rts_time
2066 		    && i != NUM_SPARES)
2067 			rts_delete(RT, rts);
2068 	}
2069 
2070 
2071 	/* finished if the active route is still fresh */
2072 	if (now_stale <= RT->rt_time)
2073 		return 0;
2074 
2075 	/* try to switch to an alternative */
2076 	rtswitch(RT, 0);
2077 
2078 	/* Delete a dead route after it has been publicly mourned. */
2079 	if (now_garbage > RT->rt_time) {
2080 		rtdelete(RT);
2081 		return 0;
2082 	}
2083 
2084 	/* Start poisoning a bad route before deleting it. */
2085 	if (now.tv_sec - RT->rt_time > EXPIRE_TIME) {
2086 		struct rt_spare new = RT->rt_spares[0];
2087 		new.rts_metric = HOPCNT_INFINITY;
2088 		rtchange(RT, RT->rt_state, &new, 0);
2089 	}
2090 	return 0;
2091 }
2092 
2093 
2094 /* Watch for dead routes and interfaces.
2095  */
2096 void
2097 age(naddr bad_gate)
2098 {
2099 	struct interface *ifp;
2100 	int need_query = 0;
2101 
2102 	/* If not listening to RIP, there is no need to age the routes in
2103 	 * the table.
2104 	 */
2105 	age_timer.tv_sec = (now.tv_sec
2106 			    + ((rip_sock < 0) ? NEVER : SUPPLY_INTERVAL));
2107 
2108 	/* Check for dead IS_REMOTE interfaces by timing their
2109 	 * transmissions.
2110 	 */
2111 	LIST_FOREACH(ifp, &ifnet, int_list) {
2112 		if (!(ifp->int_state & IS_REMOTE))
2113 			continue;
2114 
2115 		/* ignore unreachable remote interfaces */
2116 		if (!check_remote(ifp))
2117 			continue;
2118 
2119 		/* Restore remote interface that has become reachable
2120 		 */
2121 		if (ifp->int_state & IS_BROKE)
2122 			if_ok(ifp, "remote ");
2123 
2124 		if (ifp->int_act_time != NEVER
2125 		    && now.tv_sec - ifp->int_act_time > EXPIRE_TIME) {
2126 			msglog("remote interface %s to %s timed out after"
2127 			       " %ld:%ld",
2128 			       ifp->int_name,
2129 			       naddr_ntoa(ifp->int_dstaddr),
2130 			       (long)(now.tv_sec - ifp->int_act_time)/60,
2131 			       (long)(now.tv_sec - ifp->int_act_time)%60);
2132 			if_sick(ifp);
2133 		}
2134 
2135 		/* If we have not heard from the other router
2136 		 * recently, ask it.
2137 		 */
2138 		if (now.tv_sec >= ifp->int_query_time) {
2139 			ifp->int_query_time = NEVER;
2140 			need_query = 1;
2141 		}
2142 	}
2143 
2144 	/* Age routes. */
2145 	age_bad_gate = bad_gate;
2146 	(void)rn_walktree(rhead, walk_age, 0);
2147 
2148 	/* delete old redirected routes to keep the kernel table small
2149 	 * and prevent blackholes
2150 	 */
2151 	del_redirects(bad_gate, now.tv_sec-STALE_TIME);
2152 
2153 	/* Update the kernel routing table. */
2154 	fix_kern();
2155 
2156 	/* poke reticent remote gateways */
2157 	if (need_query)
2158 		rip_query();
2159 }
2160