xref: /netbsd-src/sbin/routed/if.c (revision bcc8ec9959e7b01e313d813067bfb43a3ad70551)
1 /*	$NetBSD: if.c,v 1.21 2001/01/15 13:19:12 itojun Exp $	*/
2 
3 /*
4  * Copyright (c) 1983, 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. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgment:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #if !defined(lint) && !defined(sgi) && !defined(__NetBSD__)
37 static char sccsid[] __attribute__((unused)) = "@(#)if.c	8.1 (Berkeley) 6/5/93";
38 #elif defined(__NetBSD__)
39 #include <sys/cdefs.h>
40 __RCSID("$NetBSD: if.c,v 1.21 2001/01/15 13:19:12 itojun Exp $");
41 #endif
42 
43 #include "defs.h"
44 #include "pathnames.h"
45 
46 struct interface *ifnet;		/* all interfaces */
47 
48 /* hash table for all interfaces, big enough to tolerate ridiculous
49  * numbers of IP aliases.  Crazy numbers of aliases such as 7000
50  * still will not do well, but not just in looking up interfaces
51  * by name or address.
52  */
53 #define AHASH_LEN 211			/* must be prime */
54 #define AHASH(a) &ahash_tbl[(a)%AHASH_LEN]
55 struct interface *ahash_tbl[AHASH_LEN];
56 
57 #define BHASH_LEN 211			/* must be prime */
58 #define BHASH(a) &bhash_tbl[(a)%BHASH_LEN]
59 struct interface *bhash_tbl[BHASH_LEN];
60 
61 struct interface *remote_if;		/* remote interfaces */
62 
63 /* hash for physical interface names.
64  * Assume there are never more 100 or 200 real interfaces, and that
65  * aliases are put on the end of the hash chains.
66  */
67 #define NHASH_LEN 97
68 struct interface *nhash_tbl[NHASH_LEN];
69 
70 int	tot_interfaces;			/* # of remote and local interfaces */
71 int	rip_interfaces;			/* # of interfaces doing RIP */
72 int	foundloopback;			/* valid flag for loopaddr */
73 naddr	loopaddr;			/* our address on loopback */
74 struct	rt_spare loop_rts;
75 
76 struct timeval ifinit_timer;
77 static struct timeval last_ifinit;
78 #define IF_RESCAN_DELAY() (last_ifinit.tv_sec == now.tv_sec		\
79 			   && last_ifinit.tv_usec == now.tv_usec	\
80 			   && timercmp(&ifinit_timer, &now, >))
81 
82 int	have_ripv1_out;			/* have a RIPv1 interface */
83 int	have_ripv1_in;
84 
85 
86 static struct interface**
87 nhash(char *p)
88 {
89 	u_int i;
90 
91 	for (i = 0; *p != '\0'; p++) {
92 		i = ((i<<1) & 0x7fffffff) | ((i>>31) & 1);
93 		i ^= *p;
94 	}
95 	return &nhash_tbl[i % NHASH_LEN];
96 }
97 
98 
99 /* Link a new interface into the lists and hash tables.
100  */
101 void
102 if_link(struct interface *ifp)
103 {
104 	struct interface **hifp;
105 
106 	ifp->int_prev = &ifnet;
107 	ifp->int_next = ifnet;
108 	if (ifnet != 0)
109 		ifnet->int_prev = &ifp->int_next;
110 	ifnet = ifp;
111 
112 	hifp = AHASH(ifp->int_addr);
113 	ifp->int_ahash_prev = hifp;
114 	if ((ifp->int_ahash = *hifp) != 0)
115 		(*hifp)->int_ahash_prev = &ifp->int_ahash;
116 	*hifp = ifp;
117 
118 	if (ifp->int_if_flags & IFF_BROADCAST) {
119 		hifp = BHASH(ifp->int_brdaddr);
120 		ifp->int_bhash_prev = hifp;
121 		if ((ifp->int_bhash = *hifp) != 0)
122 			(*hifp)->int_bhash_prev = &ifp->int_bhash;
123 		*hifp = ifp;
124 	}
125 
126 	if (ifp->int_state & IS_REMOTE) {
127 		ifp->int_rlink_prev = &remote_if;
128 		ifp->int_rlink = remote_if;
129 		if (remote_if != 0)
130 			remote_if->int_rlink_prev = &ifp->int_rlink;
131 		remote_if = ifp;
132 	}
133 
134 	hifp = nhash(ifp->int_name);
135 	if (ifp->int_state & IS_ALIAS) {
136 		/* put aliases on the end of the hash chain */
137 		while (*hifp != 0)
138 			hifp = &(*hifp)->int_nhash;
139 	}
140 	ifp->int_nhash_prev = hifp;
141 	if ((ifp->int_nhash = *hifp) != 0)
142 		(*hifp)->int_nhash_prev = &ifp->int_nhash;
143 	*hifp = ifp;
144 }
145 
146 
147 /* Find the interface with an address
148  */
149 struct interface *
150 ifwithaddr(naddr addr,
151 	   int	bcast,			/* notice IFF_BROADCAST address */
152 	   int	remote)			/* include IS_REMOTE interfaces */
153 {
154 	struct interface *ifp, *possible = 0;
155 
156 	remote = (remote == 0) ? IS_REMOTE : 0;
157 
158 	for (ifp = *AHASH(addr); ifp; ifp = ifp->int_ahash) {
159 		if (ifp->int_addr != addr)
160 			continue;
161 		if ((ifp->int_state & remote) != 0)
162 			continue;
163 		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
164 			return ifp;
165 		possible = ifp;
166 	}
167 
168 	if (possible || !bcast)
169 		return possible;
170 
171 	for (ifp = *BHASH(addr); ifp; ifp = ifp->int_bhash) {
172 		if (ifp->int_brdaddr != addr)
173 			continue;
174 		if ((ifp->int_state & remote) != 0)
175 			continue;
176 		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
177 			return ifp;
178 		possible = ifp;
179 	}
180 
181 	return possible;
182 }
183 
184 
185 /* find the interface with a name
186  */
187 struct interface *
188 ifwithname(char *name,			/* "ec0" or whatever */
189 	   naddr addr)			/* 0 or network address */
190 {
191 	struct interface *ifp;
192 
193 	for (;;) {
194 		for (ifp = *nhash(name); ifp != 0; ifp = ifp->int_nhash) {
195 			/* If the network address is not specified,
196 			 * ignore any alias interfaces.  Otherwise, look
197 			 * for the interface with the target name and address.
198 			 */
199 			if (!strcmp(ifp->int_name, name)
200 			    && ((addr == 0 && !(ifp->int_state & IS_ALIAS))
201 				|| (ifp->int_addr == addr)))
202 				return ifp;
203 		}
204 
205 		/* If there is no known interface, maybe there is a
206 		 * new interface.  So just once look for new interfaces.
207 		 */
208 		if (IF_RESCAN_DELAY())
209 			return 0;
210 		ifinit();
211 	}
212 }
213 
214 
215 struct interface *
216 ifwithindex(u_short index,
217 	    int rescan_ok)
218 {
219 	struct interface *ifp;
220 
221 	for (;;) {
222 		for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
223 			if (ifp->int_index == index)
224 				return ifp;
225 		}
226 
227 		/* If there is no known interface, maybe there is a
228 		 * new interface.  So just once look for new interfaces.
229 		 */
230 		if (!rescan_ok
231 		    || IF_RESCAN_DELAY())
232 			return 0;
233 		ifinit();
234 	}
235 }
236 
237 
238 /* Find an interface from which the specified address
239  * should have come from.  Used for figuring out which
240  * interface a packet came in on.
241  */
242 struct interface *
243 iflookup(naddr addr)
244 {
245 	struct interface *ifp, *maybe;
246 	int once = 0;
247 
248 	maybe = 0;
249 	for (;;) {
250 		for (ifp = ifnet; ifp; ifp = ifp->int_next) {
251 			if (ifp->int_if_flags & IFF_POINTOPOINT) {
252 				/* finished with a match */
253 				if (ifp->int_dstaddr == addr)
254 					return ifp;
255 
256 			} else {
257 				/* finished with an exact match */
258 				if (ifp->int_addr == addr)
259 					return ifp;
260 
261 				/* Look for the longest approximate match.
262 				 */
263 				if (on_net(addr, ifp->int_net, ifp->int_mask)
264 				    && (maybe == 0
265 					|| ifp->int_mask > maybe->int_mask))
266 					maybe = ifp;
267 			}
268 		}
269 
270 		if (maybe != 0 || once)
271 			return maybe;
272 
273 		/* If there is no known interface, maybe there is a
274 		 * new interface.  So just once look for new interfaces.
275 		 */
276 		ifinit();
277 		once = 1;
278 	}
279 }
280 
281 
282 /* Return the classical netmask for an IP address.
283  */
284 naddr					/* host byte order */
285 std_mask(naddr addr)			/* network byte order */
286 {
287 	NTOHL(addr);			/* was a host, not a network */
288 
289 	if (addr == 0)			/* default route has mask 0 */
290 		return 0;
291 	if (IN_CLASSA(addr))
292 		return IN_CLASSA_NET;
293 	if (IN_CLASSB(addr))
294 		return IN_CLASSB_NET;
295 	return IN_CLASSC_NET;
296 }
297 
298 
299 /* Find the netmask that would be inferred by RIPv1 listeners
300  *	on the given interface for a given network.
301  *	If no interface is specified, look for the best fitting	interface.
302  */
303 naddr
304 ripv1_mask_net(naddr addr,		/* in network byte order */
305 	       struct interface *ifp)	/* as seen on this interface */
306 {
307 	struct r1net *r1p;
308 	naddr mask = 0;
309 
310 	if (addr == 0)			/* default always has 0 mask */
311 		return mask;
312 
313 	if (ifp != 0 && ifp->int_ripv1_mask != HOST_MASK) {
314 		/* If the target network is that of the associated interface
315 		 * on which it arrived, then use the netmask of the interface.
316 		 */
317 		if (on_net(addr, ifp->int_net, ifp->int_std_mask))
318 			mask = ifp->int_ripv1_mask;
319 
320 	} else {
321 		/* Examine all interfaces, and if it the target seems
322 		 * to have the same network number of an interface, use the
323 		 * netmask of that interface.  If there is more than one
324 		 * such interface, prefer the interface with the longest
325 		 * match.
326 		 */
327 		for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
328 			if (on_net(addr, ifp->int_std_net, ifp->int_std_mask)
329 			    && ifp->int_ripv1_mask > mask
330 			    && ifp->int_ripv1_mask != HOST_MASK)
331 				mask = ifp->int_ripv1_mask;
332 		}
333 
334 	}
335 
336 	/* check special definitions */
337 	if (mask == 0) {
338 		for (r1p = r1nets; r1p != 0; r1p = r1p->r1net_next) {
339 			if (on_net(addr, r1p->r1net_net, r1p->r1net_match)
340 			    && r1p->r1net_mask > mask)
341 				mask = r1p->r1net_mask;
342 		}
343 
344 		/* Otherwise, make the classic A/B/C guess.
345 		 */
346 		if (mask == 0)
347 			mask = std_mask(addr);
348 	}
349 
350 	return mask;
351 }
352 
353 
354 naddr
355 ripv1_mask_host(naddr addr,		/* in network byte order */
356 		struct interface *ifp)	/* as seen on this interface */
357 {
358 	naddr mask = ripv1_mask_net(addr, ifp);
359 
360 
361 	/* If the computed netmask does not mask the address,
362 	 * then assume it is a host address
363 	 */
364 	if ((ntohl(addr) & ~mask) != 0)
365 		mask = HOST_MASK;
366 	return mask;
367 }
368 
369 
370 /* See if a IP address looks reasonable as a destination
371  */
372 int					/* 0=bad */
373 check_dst(naddr addr)
374 {
375 	NTOHL(addr);
376 
377 	if (IN_CLASSA(addr)) {
378 		if (addr == 0)
379 			return 1;	/* default */
380 
381 		addr >>= IN_CLASSA_NSHIFT;
382 		return (addr != 0 && addr != IN_LOOPBACKNET);
383 	}
384 
385 	return (IN_CLASSB(addr) || IN_CLASSC(addr));
386 }
387 
388 
389 /* See a new interface duplicates an existing interface.
390  */
391 struct interface *
392 check_dup(naddr addr,			/* IP address, so network byte order */
393 	  naddr dstaddr,		/* ditto */
394 	  naddr mask,			/* mask, so host byte order */
395 	  int if_flags)
396 {
397 	struct interface *ifp;
398 
399 	for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
400 		if (ifp->int_mask != mask)
401 			continue;
402 
403 		if (!iff_up(ifp->int_if_flags))
404 			continue;
405 
406 		/* The local address can only be shared with a point-to-point
407 		 * link.
408 		 */
409 		if (ifp->int_addr == addr
410 		    && (((if_flags|ifp->int_if_flags) & IFF_POINTOPOINT) == 0))
411 			return ifp;
412 
413 		if (on_net(ifp->int_dstaddr, ntohl(dstaddr),mask))
414 			return ifp;
415 	}
416 	return 0;
417 }
418 
419 
420 /* See that a remote gateway is reachable.
421  *	Note that the answer can change as real interfaces come and go.
422  */
423 int					/* 0=bad */
424 check_remote(struct interface *ifp)
425 {
426 	struct rt_entry *rt;
427 
428 	/* do not worry about other kinds */
429 	if (!(ifp->int_state & IS_REMOTE))
430 	    return 1;
431 
432 	rt = rtfind(ifp->int_addr);
433 	if (rt != 0
434 	    && rt->rt_ifp != 0
435 	    &&on_net(ifp->int_addr,
436 		     rt->rt_ifp->int_net, rt->rt_ifp->int_mask))
437 		return 1;
438 
439 	/* the gateway cannot be reached directly from one of our
440 	 * interfaces
441 	 */
442 	if (!(ifp->int_state & IS_BROKE)) {
443 		msglog("unreachable gateway %s in "_PATH_GATEWAYS,
444 		       naddr_ntoa(ifp->int_addr));
445 		if_bad(ifp);
446 	}
447 	return 0;
448 }
449 
450 
451 /* Delete an interface.
452  */
453 static void
454 ifdel(struct interface *ifp)
455 {
456 	struct ip_mreq m;
457 	struct interface *ifp1;
458 
459 
460 	trace_if("Del", ifp);
461 
462 	ifp->int_state |= IS_BROKE;
463 
464 	/* unlink the interface
465 	 */
466 	*ifp->int_prev = ifp->int_next;
467 	if (ifp->int_next != 0)
468 		ifp->int_next->int_prev = ifp->int_prev;
469 	*ifp->int_ahash_prev = ifp->int_ahash;
470 	if (ifp->int_ahash != 0)
471 		ifp->int_ahash->int_ahash_prev = ifp->int_ahash_prev;
472 	*ifp->int_nhash_prev = ifp->int_nhash;
473 	if (ifp->int_nhash != 0)
474 		ifp->int_nhash->int_nhash_prev = ifp->int_nhash_prev;
475 	if (ifp->int_if_flags & IFF_BROADCAST) {
476 		*ifp->int_bhash_prev = ifp->int_bhash;
477 		if (ifp->int_bhash != 0)
478 			ifp->int_bhash->int_bhash_prev = ifp->int_bhash_prev;
479 	}
480 	if (ifp->int_state & IS_REMOTE) {
481 		*ifp->int_rlink_prev = ifp->int_rlink;
482 		if (ifp->int_rlink != 0)
483 			ifp->int_rlink->int_rlink_prev = ifp->int_rlink_prev;
484 	}
485 
486 	if (!(ifp->int_state & IS_ALIAS)) {
487 		/* delete aliases when the main interface dies
488 		 */
489 		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
490 			if (ifp1 != ifp
491 			    && !strcmp(ifp->int_name, ifp1->int_name))
492 				ifdel(ifp1);
493 		}
494 
495 		if ((ifp->int_if_flags & IFF_MULTICAST)
496 #ifdef MCAST_PPP_BUG
497 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
498 #endif
499 		    && rip_sock >= 0) {
500 			m.imr_multiaddr.s_addr = htonl(INADDR_RIP_GROUP);
501 #ifdef MCAST_IFINDEX
502 			m.imr_interface.s_addr = htonl(ifp->int_index);
503 #else
504 			m.imr_interface.s_addr = ((ifp->int_if_flags
505 						   & IFF_POINTOPOINT)
506 						  ? ifp->int_dstaddr
507 						  : ifp->int_addr);
508 #endif
509 			if (setsockopt(rip_sock,IPPROTO_IP,IP_DROP_MEMBERSHIP,
510 				       &m, sizeof(m)) < 0
511 			    && errno != EADDRNOTAVAIL
512 			    && !TRACEACTIONS)
513 				LOGERR("setsockopt(IP_DROP_MEMBERSHIP RIP)");
514 			if (rip_sock_mcast == ifp)
515 				rip_sock_mcast = 0;
516 		}
517 		if (ifp->int_rip_sock >= 0) {
518 			(void)close(ifp->int_rip_sock);
519 			ifp->int_rip_sock = -1;
520 			fix_select();
521 		}
522 
523 		tot_interfaces--;
524 		if (!IS_RIP_OFF(ifp->int_state))
525 			rip_interfaces--;
526 
527 		/* Zap all routes associated with this interface.
528 		 * Assume routes just using gateways beyond this interface
529 		 * will timeout naturally, and have probably already died.
530 		 */
531 		(void)rn_walktree(rhead, walk_bad, 0);
532 
533 		set_rdisc_mg(ifp, 0);
534 		if_bad_rdisc(ifp);
535 	}
536 
537 	free(ifp);
538 }
539 
540 
541 /* Mark an interface ill.
542  */
543 void
544 if_sick(struct interface *ifp)
545 {
546 	if (0 == (ifp->int_state & (IS_SICK | IS_BROKE))) {
547 		ifp->int_state |= IS_SICK;
548 		ifp->int_act_time = NEVER;
549 		trace_if("Chg", ifp);
550 
551 		LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
552 	}
553 }
554 
555 
556 /* Mark an interface dead.
557  */
558 void
559 if_bad(struct interface *ifp)
560 {
561 	struct interface *ifp1;
562 
563 
564 	if (ifp->int_state & IS_BROKE)
565 		return;
566 
567 	LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
568 
569 	ifp->int_state |= (IS_BROKE | IS_SICK);
570 	ifp->int_act_time = NEVER;
571 	ifp->int_query_time = NEVER;
572 	ifp->int_data.ts = now.tv_sec;
573 
574 	trace_if("Chg", ifp);
575 
576 	if (!(ifp->int_state & IS_ALIAS)) {
577 		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
578 			if (ifp1 != ifp
579 			    && !strcmp(ifp->int_name, ifp1->int_name))
580 				if_bad(ifp1);
581 		}
582 		(void)rn_walktree(rhead, walk_bad, 0);
583 		if_bad_rdisc(ifp);
584 	}
585 }
586 
587 
588 /* Mark an interface alive
589  */
590 int					/* 1=it was dead */
591 if_ok(struct interface *ifp,
592       const char *type)
593 {
594 	struct interface *ifp1;
595 
596 
597 	if (!(ifp->int_state & IS_BROKE)) {
598 		if (ifp->int_state & IS_SICK) {
599 			trace_act("%sinterface %s to %s working better",
600 				  type,
601 				  ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
602 			ifp->int_state &= ~IS_SICK;
603 		}
604 		return 0;
605 	}
606 
607 	msglog("%sinterface %s to %s restored",
608 	       type, ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
609 	ifp->int_state &= ~(IS_BROKE | IS_SICK);
610 	ifp->int_data.ts = 0;
611 
612 	if (!(ifp->int_state & IS_ALIAS)) {
613 		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
614 			if (ifp1 != ifp
615 			    && !strcmp(ifp->int_name, ifp1->int_name))
616 				if_ok(ifp1, type);
617 		}
618 		if_ok_rdisc(ifp);
619 	}
620 
621 	if (ifp->int_state & IS_REMOTE) {
622 		if (!addrouteforif(ifp))
623 			return 0;
624 	}
625 	return 1;
626 }
627 
628 
629 /* disassemble routing message
630  */
631 void
632 rt_xaddrs(struct rt_addrinfo *info,
633 	  struct sockaddr *sa,
634 	  struct sockaddr *lim,
635 	  int addrs)
636 {
637 	int i;
638 #ifdef _HAVE_SA_LEN
639 	static struct sockaddr sa_zero;
640 #endif
641 #ifdef sgi
642 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) \
643 		    : sizeof(__uint64_t))
644 #else
645 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) \
646 		    : sizeof(long))
647 #endif
648 
649 
650 	memset(info, 0, sizeof(*info));
651 	info->rti_addrs = addrs;
652 	for (i = 0; i < RTAX_MAX && sa < lim; i++) {
653 		if ((addrs & (1 << i)) == 0)
654 			continue;
655 #ifdef _HAVE_SA_LEN
656 		info->rti_info[i] = (sa->sa_len != 0) ? sa : &sa_zero;
657 		sa = (struct sockaddr *)((char*)(sa)
658 					 + ROUNDUP(sa->sa_len));
659 #else
660 		info->rti_info[i] = sa;
661 		sa = (struct sockaddr *)((char*)(sa)
662 					 + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
663 #endif
664 	}
665 }
666 
667 
668 /* Find the network interfaces which have configured themselves.
669  *	This must be done regularly, if only for extra addresses
670  *	that come and go on interfaces.
671  */
672 void
673 ifinit(void)
674 {
675 	static char *sysctl_buf;
676 	static size_t sysctl_buf_size = 0;
677 	uint complaints = 0;
678 	static u_int prev_complaints = 0;
679 #	define COMP_NOT_INET	0x001
680 #	define COMP_NOADDR	0x002
681 #	define COMP_BADADDR	0x004
682 #	define COMP_NODST	0x008
683 #	define COMP_NOBADR	0x010
684 #	define COMP_NOMASK	0x020
685 #	define COMP_DUP		0x040
686 #	define COMP_BAD_METRIC	0x080
687 #	define COMP_NETMASK	0x100
688 
689 	struct interface ifs, ifs0, *ifp, *ifp1;
690 	struct rt_entry *rt;
691 	size_t needed;
692 	int mib[6];
693 	struct if_msghdr *ifm;
694 	struct ifa_msghdr *ifam, *ifam_lim, *ifam2;
695 	int in, ierr, out, oerr;
696 	struct intnet *intnetp;
697 	struct rt_addrinfo info;
698 #ifdef SIOCGIFMETRIC
699 	struct ifreq ifr;
700 #endif
701 
702 
703 	last_ifinit = now;
704 	ifinit_timer.tv_sec = now.tv_sec + (supplier
705 					    ? CHECK_ACT_INTERVAL
706 					    : CHECK_QUIET_INTERVAL);
707 
708 	/* mark all interfaces so we can get rid of those that disappear */
709 	for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next)
710 		ifp->int_state &= ~(IS_CHECKED | IS_DUP);
711 
712 	/* Fetch the interface list, without too many system calls
713 	 * since we do it repeatedly.
714 	 */
715 	mib[0] = CTL_NET;
716 	mib[1] = PF_ROUTE;
717 	mib[2] = 0;
718 	mib[3] = AF_INET;
719 	mib[4] = NET_RT_IFLIST;
720 	mib[5] = 0;
721 	for (;;) {
722 		if ((needed = sysctl_buf_size) != 0) {
723 			if (sysctl(mib, 6, sysctl_buf,&needed, 0, 0) >= 0)
724 				break;
725 			/* retry if the table grew */
726 			if (errno != ENOMEM && errno != EFAULT)
727 				BADERR(1, "ifinit: sysctl(RT_IFLIST)");
728 			free(sysctl_buf);
729 			needed = 0;
730 		}
731 		if (sysctl(mib, 6, 0, &needed, 0, 0) < 0)
732 			BADERR(1,"ifinit: sysctl(RT_IFLIST) estimate");
733 		sysctl_buf = rtmalloc(sysctl_buf_size = needed,
734 				      "ifinit sysctl");
735 	}
736 
737 	ifam_lim = (struct ifa_msghdr *)(sysctl_buf + needed);
738 	for (ifam = (struct ifa_msghdr *)sysctl_buf;
739 	     ifam < ifam_lim;
740 	     ifam = ifam2) {
741 
742 		ifam2 = (struct ifa_msghdr*)((char*)ifam + ifam->ifam_msglen);
743 
744 #ifdef RTM_OIFINFO
745 		if (ifam->ifam_type == RTM_OIFINFO) {
746 			continue; /* just ignore compat message */
747 		}
748 #endif
749 		if (ifam->ifam_type == RTM_IFINFO) {
750 			struct sockaddr_dl *sdl;
751 
752 			ifm = (struct if_msghdr *)ifam;
753 			/* make prototype structure for the IP aliases
754 			 */
755 			memset(&ifs0, 0, sizeof(ifs0));
756 			ifs0.int_rip_sock = -1;
757 			ifs0.int_index = ifm->ifm_index;
758 			ifs0.int_if_flags = ifm->ifm_flags;
759 			ifs0.int_state = IS_CHECKED;
760 			ifs0.int_query_time = NEVER;
761 			ifs0.int_act_time = now.tv_sec;
762 			ifs0.int_data.ts = now.tv_sec;
763 			ifs0.int_data.ipackets = ifm->ifm_data.ifi_ipackets;
764 			ifs0.int_data.ierrors = ifm->ifm_data.ifi_ierrors;
765 			ifs0.int_data.opackets = ifm->ifm_data.ifi_opackets;
766 			ifs0.int_data.oerrors = ifm->ifm_data.ifi_oerrors;
767 #ifdef sgi
768 			ifs0.int_data.odrops = ifm->ifm_data.ifi_odrops;
769 #endif
770 			sdl = (struct sockaddr_dl *)(ifm + 1);
771 			sdl->sdl_data[sdl->sdl_nlen] = 0;
772 			strncpy(ifs0.int_name, sdl->sdl_data,
773 				MIN(sizeof(ifs0.int_name), sdl->sdl_nlen));
774 			continue;
775 		}
776 		if (ifam->ifam_type != RTM_NEWADDR) {
777 			logbad(1,"ifinit: out of sync");
778 			continue;
779 		}
780 		rt_xaddrs(&info, (struct sockaddr *)(ifam+1),
781 			  (struct sockaddr *)ifam2,
782 			  ifam->ifam_addrs);
783 
784 		/* Prepare for the next address of this interface, which
785 		 * will be an alias.
786 		 * Do not output RIP or Router-Discovery packets via aliases.
787 		 */
788 		memcpy(&ifs, &ifs0, sizeof(ifs));
789 		ifs0.int_state |= (IS_ALIAS | IS_NO_RIP_OUT | IS_NO_RDISC);
790 
791 		if (INFO_IFA(&info) == 0) {
792 			if (iff_up(ifs.int_if_flags)) {
793 				if (!(prev_complaints & COMP_NOADDR))
794 					msglog("%s has no address",
795 					       ifs.int_name);
796 				complaints |= COMP_NOADDR;
797 			}
798 			continue;
799 		}
800 		if (INFO_IFA(&info)->sa_family != AF_INET) {
801 			if (iff_up(ifs.int_if_flags)) {
802 				if (!(prev_complaints & COMP_NOT_INET))
803 					trace_act("%s: not AF_INET",
804 						  ifs.int_name);
805 				complaints |= COMP_NOT_INET;
806 			}
807 			continue;
808 		}
809 
810 		ifs.int_addr = S_ADDR(INFO_IFA(&info));
811 
812 		if (ntohl(ifs.int_addr)>>24 == 0
813 		    || ntohl(ifs.int_addr)>>24 == 0xff) {
814 			if (iff_up(ifs.int_if_flags)) {
815 				if (!(prev_complaints & COMP_BADADDR))
816 					msglog("%s has a bad address",
817 					       ifs.int_name);
818 				complaints |= COMP_BADADDR;
819 			}
820 			continue;
821 		}
822 
823 		if (ifs.int_if_flags & IFF_LOOPBACK) {
824 			ifs.int_state |= IS_PASSIVE | IS_NO_RIP | IS_NO_RDISC;
825 			ifs.int_dstaddr = ifs.int_addr;
826 			ifs.int_mask = HOST_MASK;
827 			ifs.int_ripv1_mask = HOST_MASK;
828 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
829 			ifs.int_net = ntohl(ifs.int_dstaddr);
830 			if (!foundloopback) {
831 				foundloopback = 1;
832 				loopaddr = ifs.int_addr;
833 				loop_rts.rts_gate = loopaddr;
834 				loop_rts.rts_router = loopaddr;
835 			}
836 
837 		} else if (ifs.int_if_flags & IFF_POINTOPOINT) {
838 			if (INFO_BRD(&info) == 0
839 			    || INFO_BRD(&info)->sa_family != AF_INET) {
840 				if (iff_up(ifs.int_if_flags)) {
841 					if (!(prev_complaints & COMP_NODST))
842 						msglog("%s has a bad"
843 						       " destination address",
844 						       ifs.int_name);
845 					complaints |= COMP_NODST;
846 				}
847 				continue;
848 			}
849 			ifs.int_dstaddr = S_ADDR(INFO_BRD(&info));
850 			if (ntohl(ifs.int_dstaddr)>>24 == 0
851 			    || ntohl(ifs.int_dstaddr)>>24 == 0xff) {
852 				if (iff_up(ifs.int_if_flags)) {
853 					if (!(prev_complaints & COMP_NODST))
854 						msglog("%s has a bad"
855 						       " destination address",
856 						       ifs.int_name);
857 					complaints |= COMP_NODST;
858 				}
859 				continue;
860 			}
861 			ifs.int_mask = HOST_MASK;
862 			ifs.int_ripv1_mask = ntohl(S_ADDR(INFO_MASK(&info)));
863 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
864 			ifs.int_net = ntohl(ifs.int_dstaddr);
865 
866 		}  else {
867 			if (INFO_MASK(&info) == 0) {
868 				if (iff_up(ifs.int_if_flags)) {
869 					if (!(prev_complaints & COMP_NOMASK))
870 						msglog("%s has no netmask",
871 						       ifs.int_name);
872 					complaints |= COMP_NOMASK;
873 				}
874 				continue;
875 			}
876 			ifs.int_dstaddr = ifs.int_addr;
877 			ifs.int_mask = ntohl(S_ADDR(INFO_MASK(&info)));
878 			ifs.int_ripv1_mask = ifs.int_mask;
879 			ifs.int_std_mask = std_mask(ifs.int_addr);
880 			ifs.int_net = ntohl(ifs.int_addr) & ifs.int_mask;
881 			if (ifs.int_mask != ifs.int_std_mask)
882 				ifs.int_state |= IS_SUBNET;
883 
884 			if (ifs.int_if_flags & IFF_BROADCAST) {
885 				if (INFO_BRD(&info) == 0) {
886 					if (iff_up(ifs.int_if_flags)) {
887 					    if (!(prev_complaints
888 						  & COMP_NOBADR))
889 						msglog("%s has"
890 						       "no broadcast address",
891 						       ifs.int_name);
892 					    complaints |= COMP_NOBADR;
893 					}
894 					continue;
895 				}
896 				ifs.int_brdaddr = S_ADDR(INFO_BRD(&info));
897 			}
898 		}
899 		ifs.int_std_net = ifs.int_net & ifs.int_std_mask;
900 		ifs.int_std_addr = htonl(ifs.int_std_net);
901 
902 		/* Use a minimum metric of one.  Treat the interface metric
903 		 * (default 0) as an increment to the hop count of one.
904 		 *
905 		 * The metric obtained from the routing socket dump of
906 		 * interface addresses is wrong.  It is not set by the
907 		 * SIOCSIFMETRIC ioctl.
908 		 */
909 #ifdef SIOCGIFMETRIC
910 		strncpy(ifr.ifr_name, ifs.int_name, sizeof(ifr.ifr_name));
911 		if (ioctl(rt_sock, SIOCGIFMETRIC, &ifr) < 0) {
912 			DBGERR(1, "ioctl(SIOCGIFMETRIC)");
913 			ifs.int_metric = 0;
914 		} else {
915 			ifs.int_metric = ifr.ifr_metric;
916 		}
917 #else
918 		ifs.int_metric = ifam->ifam_metric;
919 #endif
920 		if (ifs.int_metric > HOPCNT_INFINITY) {
921 			ifs.int_metric = 0;
922 			if (!(prev_complaints & COMP_BAD_METRIC)
923 			    && iff_up(ifs.int_if_flags)) {
924 				complaints |= COMP_BAD_METRIC;
925 				msglog("%s has a metric of %d",
926 				       ifs.int_name, ifs.int_metric);
927 			}
928 		}
929 
930 		/* See if this is a familiar interface.
931 		 * If so, stop worrying about it if it is the same.
932 		 * Start it over if it now is to somewhere else, as happens
933 		 * frequently with PPP and SLIP.
934 		 */
935 		ifp = ifwithname(ifs.int_name, ((ifs.int_state & IS_ALIAS)
936 						? ifs.int_addr
937 						: 0));
938 		if (ifp != 0) {
939 			ifp->int_state |= IS_CHECKED;
940 
941 			if (0 != ((ifp->int_if_flags ^ ifs.int_if_flags)
942 				  & (IFF_BROADCAST
943 				     | IFF_LOOPBACK
944 				     | IFF_POINTOPOINT
945 				     | IFF_MULTICAST))
946 			    || 0 != ((ifp->int_state ^ ifs.int_state)
947 				     & IS_ALIAS)
948 			    || ifp->int_addr != ifs.int_addr
949 			    || ifp->int_brdaddr != ifs.int_brdaddr
950 			    || ifp->int_dstaddr != ifs.int_dstaddr
951 			    || ifp->int_mask != ifs.int_mask
952 			    || ifp->int_metric != ifs.int_metric) {
953 				/* Forget old information about
954 				 * a changed interface.
955 				 */
956 				trace_act("interface %s has changed",
957 					  ifp->int_name);
958 				ifdel(ifp);
959 				ifp = 0;
960 			}
961 		}
962 
963 		if (ifp != 0) {
964 			/* The primary representative of an alias worries
965 			 * about how things are working.
966 			 */
967 			if (ifp->int_state & IS_ALIAS)
968 				continue;
969 
970 			/* note interfaces that have been turned off
971 			 */
972 			if (!iff_up(ifs.int_if_flags)) {
973 				if (iff_up(ifp->int_if_flags)) {
974 					msglog("interface %s to %s turned off",
975 					       ifp->int_name,
976 					       naddr_ntoa(ifp->int_dstaddr));
977 					if_bad(ifp);
978 					ifp->int_if_flags &= ~IFF_UP;
979 				} else if (now.tv_sec>(ifp->int_data.ts
980 						       + CHECK_BAD_INTERVAL)) {
981 					trace_act("interface %s has been off"
982 						  " %ld seconds; forget it",
983 						  ifp->int_name,
984 						  now.tv_sec-ifp->int_data.ts);
985 					ifdel(ifp);
986 				}
987 				continue;
988 			}
989 			/* or that were off and are now ok */
990 			if (!iff_up(ifp->int_if_flags)) {
991 				ifp->int_if_flags |= IFF_UP;
992 				(void)if_ok(ifp, "");
993 			}
994 
995 			/* If it has been long enough,
996 			 * see if the interface is broken.
997 			 */
998 			if (now.tv_sec < ifp->int_data.ts+CHECK_BAD_INTERVAL)
999 				continue;
1000 
1001 			in = ifs.int_data.ipackets - ifp->int_data.ipackets;
1002 			ierr = ifs.int_data.ierrors - ifp->int_data.ierrors;
1003 			out = ifs.int_data.opackets - ifp->int_data.opackets;
1004 			oerr = ifs.int_data.oerrors - ifp->int_data.oerrors;
1005 #ifdef sgi
1006 			/* Through at least IRIX 6.2, PPP and SLIP
1007 			 * count packets dropped by the filters.
1008 			 * But FDDI rings stuck non-operational count
1009 			 * dropped packets as they wait for improvement.
1010 			 */
1011 			if (!(ifp->int_if_flags & IFF_POINTOPOINT))
1012 				oerr += (ifs.int_data.odrops
1013 					 - ifp->int_data.odrops);
1014 #endif
1015 			/* If the interface just awoke, restart the counters.
1016 			 */
1017 			if (ifp->int_data.ts == 0) {
1018 				ifp->int_data = ifs.int_data;
1019 				continue;
1020 			}
1021 			ifp->int_data = ifs.int_data;
1022 
1023 			/* Withhold judgment when the short error
1024 			 * counters wrap or the interface is reset.
1025 			 */
1026 			if (ierr < 0 || in < 0 || oerr < 0 || out < 0) {
1027 				LIM_SEC(ifinit_timer,
1028 					now.tv_sec+CHECK_BAD_INTERVAL);
1029 				continue;
1030 			}
1031 
1032 			/* Withhold judgement when there is no traffic
1033 			 */
1034 			if (in == 0 && out == 0 && ierr == 0 && oerr == 0)
1035 				continue;
1036 
1037 			/* It is bad if input or output is not working.
1038 			 * Require presistent problems before marking it dead.
1039 			 */
1040 			if ((in <= ierr && ierr > 0)
1041 			    || (out <= oerr && oerr > 0)) {
1042 				if (!(ifp->int_state & IS_SICK)) {
1043 					trace_act("interface %s to %s"
1044 						  " sick: in=%d ierr=%d"
1045 						  " out=%d oerr=%d",
1046 						  ifp->int_name,
1047 						  naddr_ntoa(ifp->int_dstaddr),
1048 						  in, ierr, out, oerr);
1049 					if_sick(ifp);
1050 					continue;
1051 				}
1052 				if (!(ifp->int_state & IS_BROKE)) {
1053 					msglog("interface %s to %s broken:"
1054 					       " in=%d ierr=%d out=%d oerr=%d",
1055 					       ifp->int_name,
1056 					       naddr_ntoa(ifp->int_dstaddr),
1057 					       in, ierr, out, oerr);
1058 					if_bad(ifp);
1059 				}
1060 				continue;
1061 			}
1062 
1063 			/* otherwise, it is active and healthy
1064 			 */
1065 			ifp->int_act_time = now.tv_sec;
1066 			(void)if_ok(ifp, "");
1067 			continue;
1068 		}
1069 
1070 		/* This is a new interface.
1071 		 * If it is dead, forget it.
1072 		 */
1073 		if (!iff_up(ifs.int_if_flags))
1074 			continue;
1075 
1076 		/* If it duplicates an existing interface,
1077 		 * complain about it, mark the other one
1078 		 * duplicated, and forget this one.
1079 		 */
1080 		ifp = check_dup(ifs.int_addr,ifs.int_dstaddr,ifs.int_mask,
1081 				ifs.int_if_flags);
1082 		if (ifp != 0) {
1083 			/* Ignore duplicates of itself, caused by having
1084 			 * IP aliases on the same network.
1085 			 */
1086 			if (!strcmp(ifp->int_name, ifs.int_name))
1087 				continue;
1088 
1089 			if (!(prev_complaints & COMP_DUP)) {
1090 				complaints |= COMP_DUP;
1091 				msglog("%s (%s%s%s) is duplicated by"
1092 				       " %s (%s%s%s)",
1093 				       ifs.int_name,
1094 				       addrname(ifs.int_addr,ifs.int_mask,1),
1095 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1096 					? "-->" : ""),
1097 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1098 					? naddr_ntoa(ifs.int_dstaddr) : ""),
1099 				       ifp->int_name,
1100 				       addrname(ifp->int_addr,ifp->int_mask,1),
1101 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1102 					? "-->" : ""),
1103 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1104 					? naddr_ntoa(ifp->int_dstaddr) : ""));
1105 			}
1106 			ifp->int_state |= IS_DUP;
1107 			continue;
1108 		}
1109 
1110 		if (0 == (ifs.int_if_flags & (IFF_POINTOPOINT | IFF_BROADCAST))
1111 		    && !(ifs.int_state & IS_PASSIVE)) {
1112 			trace_act("%s is neither broadcast, point-to-point,"
1113 				  " nor loopback",
1114 				  ifs.int_name);
1115 			if (!(ifs.int_state & IFF_MULTICAST))
1116 				ifs.int_state |= IS_NO_RDISC;
1117 		}
1118 
1119 
1120 		/* It is new and ok.   Add it to the list of interfaces
1121 		 */
1122 		ifp = (struct interface *)rtmalloc(sizeof(*ifp), "ifinit ifp");
1123 		memcpy(ifp, &ifs, sizeof(*ifp));
1124 		get_parms(ifp);
1125 		if_link(ifp);
1126 		trace_if("Add", ifp);
1127 
1128 		/* Notice likely bad netmask.
1129 		 */
1130 		if (!(prev_complaints & COMP_NETMASK)
1131 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
1132 		    && ifp->int_addr != RIP_DEFAULT) {
1133 			for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
1134 				if (ifp1->int_mask == ifp->int_mask)
1135 					continue;
1136 				if (ifp1->int_if_flags & IFF_POINTOPOINT)
1137 					continue;
1138 				if (ifp1->int_dstaddr == RIP_DEFAULT)
1139 					continue;
1140 				if (on_net(ifp->int_dstaddr,
1141 					   ifp1->int_net, ifp1->int_mask)
1142 				    || on_net(ifp1->int_dstaddr,
1143 					      ifp->int_net, ifp->int_mask)) {
1144 					msglog("possible netmask problem"
1145 					       " between %s:%s and %s:%s",
1146 					       ifp->int_name,
1147 					       addrname(htonl(ifp->int_net),
1148 							ifp->int_mask, 1),
1149 					       ifp1->int_name,
1150 					       addrname(htonl(ifp1->int_net),
1151 							ifp1->int_mask, 1));
1152 					complaints |= COMP_NETMASK;
1153 				}
1154 			}
1155 		}
1156 
1157 		if (!(ifp->int_state & IS_ALIAS)) {
1158 			/* Count the # of directly connected networks.
1159 			 */
1160 			if (!(ifp->int_if_flags & IFF_LOOPBACK))
1161 				tot_interfaces++;
1162 			if (!IS_RIP_OFF(ifp->int_state))
1163 				rip_interfaces++;
1164 
1165 			/* turn on router discovery and RIP If needed */
1166 			if_ok_rdisc(ifp);
1167 			rip_on(ifp);
1168 		}
1169 	}
1170 
1171 	/* If we are multi-homed and have at least two interfaces
1172 	 * listening to RIP, then output by default.
1173 	 */
1174 	if (!supplier_set && rip_interfaces > 1)
1175 		set_supplier();
1176 
1177 	/* If we are multi-homed, optionally advertise a route to
1178 	 * our main address.
1179 	 */
1180 	if (advertise_mhome
1181 	    || (tot_interfaces > 1
1182 		&& mhome
1183 		&& (ifp = ifwithaddr(myaddr, 0, 0)) != 0
1184 		&& foundloopback)) {
1185 		advertise_mhome = 1;
1186 		rt = rtget(myaddr, HOST_MASK);
1187 		if (rt != 0) {
1188 			if (rt->rt_ifp != ifp
1189 			    || rt->rt_router != loopaddr) {
1190 				rtdelete(rt);
1191 				rt = 0;
1192 			} else {
1193 				loop_rts.rts_ifp = ifp;
1194 				loop_rts.rts_metric = 0;
1195 				loop_rts.rts_time = rt->rt_time;
1196 				rtchange(rt, rt->rt_state | RS_MHOME,
1197 					 &loop_rts, 0);
1198 			}
1199 		}
1200 		if (rt == 0) {
1201 			loop_rts.rts_ifp = ifp;
1202 			loop_rts.rts_metric = 0;
1203 			rtadd(myaddr, HOST_MASK, RS_MHOME, &loop_rts);
1204 		}
1205 	}
1206 
1207 	for (ifp = ifnet; ifp != 0; ifp = ifp1) {
1208 		ifp1 = ifp->int_next;	/* because we may delete it */
1209 
1210 		/* Forget any interfaces that have disappeared.
1211 		 */
1212 		if (!(ifp->int_state & (IS_CHECKED | IS_REMOTE))) {
1213 			trace_act("interface %s has disappeared",
1214 				  ifp->int_name);
1215 			ifdel(ifp);
1216 			continue;
1217 		}
1218 
1219 		if ((ifp->int_state & IS_BROKE)
1220 		    && !(ifp->int_state & IS_PASSIVE))
1221 			LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
1222 
1223 		/* If we ever have a RIPv1 interface, assume we always will.
1224 		 * It might come back if it ever goes away.
1225 		 */
1226 		if (!(ifp->int_state & IS_NO_RIPV1_OUT) && supplier)
1227 			have_ripv1_out = 1;
1228 		if (!(ifp->int_state & IS_NO_RIPV1_IN))
1229 			have_ripv1_in = 1;
1230 	}
1231 
1232 	for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
1233 		/* Ensure there is always a network route for interfaces,
1234 		 * after any dead interfaces have been deleted, which
1235 		 * might affect routes for point-to-point links.
1236 		 */
1237 		if (!addrouteforif(ifp))
1238 			continue;
1239 
1240 		/* Add routes to the local end of point-to-point interfaces
1241 		 * using loopback.
1242 		 */
1243 		if ((ifp->int_if_flags & IFF_POINTOPOINT)
1244 		    && !(ifp->int_state & IS_REMOTE)
1245 		    && foundloopback) {
1246 			/* Delete any routes to the network address through
1247 			 * foreign routers. Remove even static routes.
1248 			 */
1249 			del_static(ifp->int_addr, HOST_MASK, 0, 0);
1250 			rt = rtget(ifp->int_addr, HOST_MASK);
1251 			if (rt != 0 && rt->rt_router != loopaddr) {
1252 				rtdelete(rt);
1253 				rt = 0;
1254 			}
1255 			if (rt != 0) {
1256 				if (!(rt->rt_state & RS_LOCAL)
1257 				    || rt->rt_metric > ifp->int_metric) {
1258 					ifp1 = ifp;
1259 				} else {
1260 					ifp1 = rt->rt_ifp;
1261 				}
1262 				loop_rts.rts_ifp = ifp1;
1263 				loop_rts.rts_metric = 0;
1264 				loop_rts.rts_time = rt->rt_time;
1265 				rtchange(rt, ((rt->rt_state & ~RS_NET_SYN)
1266 					      | (RS_IF|RS_LOCAL)),
1267 					 &loop_rts, 0);
1268 			} else {
1269 				loop_rts.rts_ifp = ifp;
1270 				loop_rts.rts_metric = 0;
1271 				rtadd(ifp->int_addr, HOST_MASK,
1272 				      (RS_IF | RS_LOCAL), &loop_rts);
1273 			}
1274 		}
1275 	}
1276 
1277 	/* add the authority routes */
1278 	for (intnetp = intnets; intnetp!=0; intnetp = intnetp->intnet_next) {
1279 		rt = rtget(intnetp->intnet_addr, intnetp->intnet_mask);
1280 		if (rt != 0
1281 		    && !(rt->rt_state & RS_NO_NET_SYN)
1282 		    && !(rt->rt_state & RS_NET_INT)) {
1283 			rtdelete(rt);
1284 			rt = 0;
1285 		}
1286 		if (rt == 0) {
1287 			loop_rts.rts_ifp = 0;
1288 			loop_rts.rts_metric = intnetp->intnet_metric-1;
1289 			rtadd(intnetp->intnet_addr, intnetp->intnet_mask,
1290 			      RS_NET_SYN | RS_NET_INT, &loop_rts);
1291 		}
1292 	}
1293 
1294 	prev_complaints = complaints;
1295 }
1296 
1297 
1298 static void
1299 check_net_syn(struct interface *ifp)
1300 {
1301 	struct rt_entry *rt;
1302 	static struct rt_spare new;
1303 
1304 
1305 	/* Turn on the need to automatically synthesize a network route
1306 	 * for this interface only if we are running RIPv1 on some other
1307 	 * interface that is on a different class-A,B,or C network.
1308 	 */
1309 	if (have_ripv1_out || have_ripv1_in) {
1310 		ifp->int_state |= IS_NEED_NET_SYN;
1311 		rt = rtget(ifp->int_std_addr, ifp->int_std_mask);
1312 		if (rt != 0
1313 		    && 0 == (rt->rt_state & RS_NO_NET_SYN)
1314 		    && (!(rt->rt_state & RS_NET_SYN)
1315 			|| rt->rt_metric > ifp->int_metric)) {
1316 			rtdelete(rt);
1317 			rt = 0;
1318 		}
1319 		if (rt == 0) {
1320 			new.rts_ifp = ifp;
1321 			new.rts_gate = ifp->int_addr;
1322 			new.rts_router = ifp->int_addr;
1323 			new.rts_metric = ifp->int_metric;
1324 			rtadd(ifp->int_std_addr, ifp->int_std_mask,
1325 			      RS_NET_SYN, &new);
1326 		}
1327 
1328 	} else {
1329 		ifp->int_state &= ~IS_NEED_NET_SYN;
1330 
1331 		rt = rtget(ifp->int_std_addr,
1332 			   ifp->int_std_mask);
1333 		if (rt != 0
1334 		    && (rt->rt_state & RS_NET_SYN)
1335 		    && rt->rt_ifp == ifp)
1336 			rtbad_sub(rt);
1337 	}
1338 }
1339 
1340 
1341 /* Add route for interface if not currently installed.
1342  * Create route to other end if a point-to-point link,
1343  * otherwise a route to this (sub)network.
1344  */
1345 int					/* 0=bad interface */
1346 addrouteforif(struct interface *ifp)
1347 {
1348 	struct rt_entry *rt;
1349 	static struct rt_spare new;
1350 	naddr dst;
1351 
1352 
1353 	/* skip sick interfaces
1354 	 */
1355 	if (ifp->int_state & IS_BROKE)
1356 		return 0;
1357 
1358 	/* If the interface on a subnet, then install a RIPv1 route to
1359 	 * the network as well (unless it is sick).
1360 	 */
1361 	if (ifp->int_state & IS_SUBNET)
1362 		check_net_syn(ifp);
1363 
1364 	dst = (0 != (ifp->int_if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK))
1365 	       ? ifp->int_dstaddr
1366 	       : htonl(ifp->int_net));
1367 
1368 	new.rts_ifp = ifp;
1369 	new.rts_router = ifp->int_addr;
1370 	new.rts_gate = ifp->int_addr;
1371 	new.rts_metric = ifp->int_metric;
1372 	new.rts_time = now.tv_sec;
1373 
1374 	/* If we are going to send packets to the gateway,
1375 	 * it must be reachable using our physical interfaces
1376 	 */
1377 	if ((ifp->int_state & IS_REMOTE)
1378 	    && !(ifp->int_state & IS_EXTERNAL)
1379 	    && !check_remote(ifp))
1380 		return 0;
1381 
1382 	/* We are finished if the correct main interface route exists.
1383 	 * The right route must be for the right interface, not synthesized
1384 	 * from a subnet, be a "gateway" or not as appropriate, and so forth.
1385 	 */
1386 	del_static(dst, ifp->int_mask, 0, 0);
1387 	rt = rtget(dst, ifp->int_mask);
1388 	if (rt != 0) {
1389 		if ((rt->rt_ifp != ifp
1390 		     || rt->rt_router != ifp->int_addr)
1391 		    && (!(ifp->int_state & IS_DUP)
1392 			|| rt->rt_ifp == 0
1393 			|| (rt->rt_ifp->int_state & IS_BROKE))) {
1394 			rtdelete(rt);
1395 			rt = 0;
1396 		} else {
1397 			rtchange(rt, ((rt->rt_state | RS_IF)
1398 				      & ~(RS_NET_SYN | RS_LOCAL)),
1399 				 &new, 0);
1400 		}
1401 	}
1402 	if (rt == 0) {
1403 		if (ifp->int_transitions++ > 0)
1404 			trace_act("re-install interface %s",
1405 				  ifp->int_name);
1406 
1407 		rtadd(dst, ifp->int_mask, RS_IF, &new);
1408 	}
1409 
1410 	return 1;
1411 }
1412