xref: /dragonfly/sbin/routed/if.c (revision e98bdfd3)
1 /*
2  * Copyright (c) 1983, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD: src/sbin/routed/if.c,v 1.6.2.1 2000/08/14 17:00:03 sheldonh Exp $
30  */
31 
32 #include "defs.h"
33 #include "pathnames.h"
34 
35 #if !defined(sgi) && !defined(__NetBSD__)
36 static char sccsid[] __attribute__((unused)) = "@(#)if.c	8.1 (Berkeley) 6/5/93";
37 #elif defined(__NetBSD__)
38 #include <sys/cdefs.h>
39 __RCSID("$NetBSD$");
40 #endif
41 
42 struct interface *ifnet;		/* all interfaces */
43 
44 /* hash table for all interfaces, big enough to tolerate ridiculous
45  * numbers of IP aliases.  Crazy numbers of aliases such as 7000
46  * still will not do well, but not just in looking up interfaces
47  * by name or address.
48  */
49 #define AHASH_LEN 211			/* must be prime */
50 #define AHASH(a) &ahash_tbl[(a)%AHASH_LEN]
51 struct interface *ahash_tbl[AHASH_LEN];
52 
53 #define BHASH_LEN 211			/* must be prime */
54 #define BHASH(a) &bhash_tbl[(a)%BHASH_LEN]
55 struct interface *bhash_tbl[BHASH_LEN];
56 
57 struct interface *remote_if;		/* remote interfaces */
58 
59 /* hash for physical interface names.
60  * Assume there are never more 100 or 200 real interfaces, and that
61  * aliases are put on the end of the hash chains.
62  */
63 #define NHASH_LEN 97
64 struct interface *nhash_tbl[NHASH_LEN];
65 
66 int	tot_interfaces;			/* # of remote and local interfaces */
67 int	rip_interfaces;			/* # of interfaces doing RIP */
68 int	foundloopback;			/* valid flag for loopaddr */
69 naddr	loopaddr;			/* our address on loopback */
70 struct	rt_spare loop_rts;
71 
72 struct timeval ifinit_timer;
73 static struct timeval last_ifinit;
74 #define IF_RESCAN_DELAY() (last_ifinit.tv_sec == now.tv_sec		\
75 			   && last_ifinit.tv_usec == now.tv_usec	\
76 			   && timercmp(&ifinit_timer, &now, >))
77 
78 int	have_ripv1_out;			/* have a RIPv1 interface */
79 int	have_ripv1_in;
80 
81 
82 static struct interface**
83 nhash(char *p)
84 {
85 	u_int i;
86 
87 	for (i = 0; *p != '\0'; p++) {
88 		i = ((i<<1) & 0x7fffffff) | ((i>>31) & 1);
89 		i ^= *p;
90 	}
91 	return &nhash_tbl[i % NHASH_LEN];
92 }
93 
94 
95 /* Link a new interface into the lists and hash tables.
96  */
97 void
98 if_link(struct interface *ifp)
99 {
100 	struct interface **hifp;
101 
102 	ifp->int_prev = &ifnet;
103 	ifp->int_next = ifnet;
104 	if (ifnet != NULL)
105 		ifnet->int_prev = &ifp->int_next;
106 	ifnet = ifp;
107 
108 	hifp = AHASH(ifp->int_addr);
109 	ifp->int_ahash_prev = hifp;
110 	if ((ifp->int_ahash = *hifp) != NULL)
111 		(*hifp)->int_ahash_prev = &ifp->int_ahash;
112 	*hifp = ifp;
113 
114 	if (ifp->int_if_flags & IFF_BROADCAST) {
115 		hifp = BHASH(ifp->int_brdaddr);
116 		ifp->int_bhash_prev = hifp;
117 		if ((ifp->int_bhash = *hifp) != NULL)
118 			(*hifp)->int_bhash_prev = &ifp->int_bhash;
119 		*hifp = ifp;
120 	}
121 
122 	if (ifp->int_state & IS_REMOTE) {
123 		ifp->int_rlink_prev = &remote_if;
124 		ifp->int_rlink = remote_if;
125 		if (remote_if != NULL)
126 			remote_if->int_rlink_prev = &ifp->int_rlink;
127 		remote_if = ifp;
128 	}
129 
130 	hifp = nhash(ifp->int_name);
131 	if (ifp->int_state & IS_ALIAS) {
132 		/* put aliases on the end of the hash chain */
133 		while (*hifp != NULL)
134 			hifp = &(*hifp)->int_nhash;
135 	}
136 	ifp->int_nhash_prev = hifp;
137 	if ((ifp->int_nhash = *hifp) != NULL)
138 		(*hifp)->int_nhash_prev = &ifp->int_nhash;
139 	*hifp = ifp;
140 }
141 
142 
143 /* Find the interface with an address
144  */
145 struct interface *
146 ifwithaddr(naddr addr,
147 	   int	bcast,			/* notice IFF_BROADCAST address */
148 	   int	remote)			/* include IS_REMOTE interfaces */
149 {
150 	struct interface *ifp, *possible = NULL;
151 
152 	remote = (remote == 0) ? IS_REMOTE : 0;
153 
154 	for (ifp = *AHASH(addr); ifp; ifp = ifp->int_ahash) {
155 		if (ifp->int_addr != addr)
156 			continue;
157 		if ((ifp->int_state & remote) != 0)
158 			continue;
159 		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
160 			return ifp;
161 		possible = ifp;
162 	}
163 
164 	if (possible || !bcast)
165 		return possible;
166 
167 	for (ifp = *BHASH(addr); ifp; ifp = ifp->int_bhash) {
168 		if (ifp->int_brdaddr != addr)
169 			continue;
170 		if ((ifp->int_state & remote) != 0)
171 			continue;
172 		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
173 			return ifp;
174 		possible = ifp;
175 	}
176 
177 	return possible;
178 }
179 
180 
181 /* find the interface with a name
182  */
183 struct interface *
184 ifwithname(char *name,			/* "ec0" or whatever */
185 	   naddr addr)			/* 0 or network address */
186 {
187 	struct interface *ifp;
188 
189 	for (;;) {
190 		for (ifp = *nhash(name); ifp != NULL; ifp = ifp->int_nhash) {
191 			/* If the network address is not specified,
192 			 * ignore any alias interfaces.  Otherwise, look
193 			 * for the interface with the target name and address.
194 			 */
195 			if (!strcmp(ifp->int_name, name)
196 			    && ((addr == 0 && !(ifp->int_state & IS_ALIAS))
197 				|| (ifp->int_addr == addr)))
198 				return ifp;
199 		}
200 
201 		/* If there is no known interface, maybe there is a
202 		 * new interface.  So just once look for new interfaces.
203 		 */
204 		if (IF_RESCAN_DELAY())
205 			return 0;
206 		ifinit();
207 	}
208 }
209 
210 
211 struct interface *
212 ifwithindex(u_short idx, int rescan_ok)
213 {
214 	struct interface *ifp;
215 
216 	for (;;) {
217 		for (ifp = ifnet; NULL != ifp; ifp = ifp->int_next) {
218 			if (ifp->int_index == idx)
219 				return ifp;
220 		}
221 
222 		/* If there is no known interface, maybe there is a
223 		 * new interface.  So just once look for new interfaces.
224 		 */
225 		if (!rescan_ok
226 		    || IF_RESCAN_DELAY())
227 			return 0;
228 		ifinit();
229 	}
230 }
231 
232 
233 /* Find an interface from which the specified address
234  * should have come from.  Used for figuring out which
235  * interface a packet came in on.
236  */
237 struct interface *
238 iflookup(naddr addr)
239 {
240 	struct interface *ifp, *maybe;
241 
242 	maybe = NULL;
243 	for (;;) {
244 		for (ifp = ifnet; ifp; ifp = ifp->int_next) {
245 			if (ifp->int_if_flags & IFF_POINTOPOINT) {
246 				/* finished with a match */
247 				if (ifp->int_dstaddr == addr)
248 					return ifp;
249 
250 			} else {
251 				/* finished with an exact match */
252 				if (ifp->int_addr == addr)
253 					return ifp;
254 
255 				/* Look for the longest approximate match.
256 				 */
257 				if (on_net(addr, ifp->int_net, ifp->int_mask)
258 				    && (maybe == NULL
259 					|| ifp->int_mask > maybe->int_mask))
260 					maybe = ifp;
261 			}
262 		}
263 
264 		if (maybe != NULL
265 		    || IF_RESCAN_DELAY())
266 			return maybe;
267 
268 		/* If there is no known interface, maybe there is a
269 		 * new interface.  So just once look for new interfaces.
270 		 */
271 		ifinit();
272 	}
273 }
274 
275 
276 /* Return the classical netmask for an IP address.
277  */
278 naddr					/* host byte order */
279 std_mask(naddr addr)			/* network byte order */
280 {
281 	addr = ntohl(addr);		/* was a host, not a network */
282 
283 	if (addr == 0)			/* default route has mask 0 */
284 		return 0;
285 	if (IN_CLASSA(addr))
286 		return IN_CLASSA_NET;
287 	if (IN_CLASSB(addr))
288 		return IN_CLASSB_NET;
289 	return IN_CLASSC_NET;
290 }
291 
292 
293 /* Find the netmask that would be inferred by RIPv1 listeners
294  *	on the given interface for a given network.
295  *	If no interface is specified, look for the best fitting	interface.
296  */
297 naddr
298 ripv1_mask_net(naddr addr,		/* in network byte order */
299 	       struct interface *ifp)	/* as seen on this interface */
300 {
301 	struct r1net *r1p;
302 	naddr mask = 0;
303 
304 	if (addr == 0)			/* default always has 0 mask */
305 		return mask;
306 
307 	if (ifp != NULL && ifp->int_ripv1_mask != HOST_MASK) {
308 		/* If the target network is that of the associated interface
309 		 * on which it arrived, then use the netmask of the interface.
310 		 */
311 		if (on_net(addr, ifp->int_net, ifp->int_std_mask))
312 			mask = ifp->int_ripv1_mask;
313 
314 	} else {
315 		/* Examine all interfaces, and if it the target seems
316 		 * to have the same network number of an interface, use the
317 		 * netmask of that interface.  If there is more than one
318 		 * such interface, prefer the interface with the longest
319 		 * match.
320 		 */
321 		for (ifp = ifnet; ifp != NULL; ifp = ifp->int_next) {
322 			if (on_net(addr, ifp->int_std_net, ifp->int_std_mask)
323 			    && ifp->int_ripv1_mask > mask
324 			    && ifp->int_ripv1_mask != HOST_MASK)
325 				mask = ifp->int_ripv1_mask;
326 		}
327 
328 	}
329 
330 	/* check special definitions */
331 	if (mask == 0) {
332 		for (r1p = r1nets; r1p != NULL; r1p = r1p->r1net_next) {
333 			if (on_net(addr, r1p->r1net_net, r1p->r1net_match)
334 			    && r1p->r1net_mask > mask)
335 				mask = r1p->r1net_mask;
336 		}
337 
338 		/* Otherwise, make the classic A/B/C guess.
339 		 */
340 		if (mask == 0)
341 			mask = std_mask(addr);
342 	}
343 
344 	return mask;
345 }
346 
347 
348 naddr
349 ripv1_mask_host(naddr addr,		/* in network byte order */
350 		struct interface *ifp)	/* as seen on this interface */
351 {
352 	naddr mask = ripv1_mask_net(addr, ifp);
353 
354 
355 	/* If the computed netmask does not mask the address,
356 	 * then assume it is a host address
357 	 */
358 	if ((ntohl(addr) & ~mask) != 0)
359 		mask = HOST_MASK;
360 	return mask;
361 }
362 
363 
364 /* See if a IP address looks reasonable as a destination
365  */
366 int					/* 0=bad */
367 check_dst(naddr addr)
368 {
369 	addr = ntohl(addr);
370 
371 	if (IN_CLASSA(addr)) {
372 		if (addr == 0)
373 			return 1;	/* default */
374 
375 		addr >>= IN_CLASSA_NSHIFT;
376 		return (addr != 0 && addr != IN_LOOPBACKNET);
377 	}
378 
379 	return (IN_CLASSB(addr) || IN_CLASSC(addr));
380 }
381 
382 
383 /* See a new interface duplicates an existing interface.
384  */
385 struct interface *
386 check_dup(naddr addr,			/* IP address, so network byte order */
387 	  naddr dstaddr,		/* ditto */
388 	  naddr mask,			/* mask, so host byte order */
389 	  int if_flags)
390 {
391 	struct interface *ifp;
392 
393 	for (ifp = ifnet; NULL != ifp; ifp = ifp->int_next) {
394 		if (ifp->int_mask != mask)
395 			continue;
396 
397 		if (!iff_up(ifp->int_if_flags))
398 			continue;
399 
400 		/* The local address can only be shared with a point-to-point
401 		 * link.
402 		 */
403 		if (ifp->int_addr == addr
404 		    && (((if_flags|ifp->int_if_flags) & IFF_POINTOPOINT) == 0))
405 			return ifp;
406 
407 		if (on_net(ifp->int_dstaddr, ntohl(dstaddr),mask))
408 			return ifp;
409 	}
410 	return 0;
411 }
412 
413 
414 /* See that a remote gateway is reachable.
415  *	Note that the answer can change as real interfaces come and go.
416  */
417 int					/* 0=bad */
418 check_remote(struct interface *ifp)
419 {
420 	struct rt_entry *rt;
421 
422 	/* do not worry about other kinds */
423 	if (!(ifp->int_state & IS_REMOTE))
424 	    return 1;
425 
426 	rt = rtfind(ifp->int_addr);
427 	if (rt != NULL
428 	    && rt->rt_ifp != 0
429 	    &&on_net(ifp->int_addr,
430 		     rt->rt_ifp->int_net, rt->rt_ifp->int_mask))
431 		return 1;
432 
433 	/* the gateway cannot be reached directly from one of our
434 	 * interfaces
435 	 */
436 	if (!(ifp->int_state & IS_BROKE)) {
437 		msglog("unreachable gateway %s in "_PATH_GATEWAYS,
438 		       naddr_ntoa(ifp->int_addr));
439 		if_bad(ifp);
440 	}
441 	return 0;
442 }
443 
444 
445 /* Delete an interface.
446  */
447 static void
448 ifdel(struct interface *ifp)
449 {
450 	struct ip_mreq m;
451 	struct interface *ifp1;
452 
453 
454 	trace_if("Del", ifp);
455 
456 	ifp->int_state |= IS_BROKE;
457 
458 	/* unlink the interface
459 	 */
460 	*ifp->int_prev = ifp->int_next;
461 	if (ifp->int_next != 0)
462 		ifp->int_next->int_prev = ifp->int_prev;
463 	*ifp->int_ahash_prev = ifp->int_ahash;
464 	if (ifp->int_ahash != 0)
465 		ifp->int_ahash->int_ahash_prev = ifp->int_ahash_prev;
466 	*ifp->int_nhash_prev = ifp->int_nhash;
467 	if (ifp->int_nhash != 0)
468 		ifp->int_nhash->int_nhash_prev = ifp->int_nhash_prev;
469 	if (ifp->int_if_flags & IFF_BROADCAST) {
470 		*ifp->int_bhash_prev = ifp->int_bhash;
471 		if (ifp->int_bhash != 0)
472 			ifp->int_bhash->int_bhash_prev = ifp->int_bhash_prev;
473 	}
474 	if (ifp->int_state & IS_REMOTE) {
475 		*ifp->int_rlink_prev = ifp->int_rlink;
476 		if (ifp->int_rlink != 0)
477 			ifp->int_rlink->int_rlink_prev = ifp->int_rlink_prev;
478 	}
479 
480 	if (!(ifp->int_state & IS_ALIAS)) {
481 		/* delete aliases when the main interface dies
482 		 */
483 		for (ifp1 = ifnet; NULL != ifp1; ifp1 = ifp1->int_next) {
484 			if (ifp1 != ifp
485 			    && !strcmp(ifp->int_name, ifp1->int_name))
486 				ifdel(ifp1);
487 		}
488 
489 		if ((ifp->int_if_flags & IFF_MULTICAST)
490 #ifdef MCAST_PPP_BUG
491 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
492 #endif
493 		    && rip_sock >= 0) {
494 			m.imr_multiaddr.s_addr = htonl(INADDR_RIP_GROUP);
495 			m.imr_interface.s_addr = ((ifp->int_if_flags
496 						   & IFF_POINTOPOINT)
497 						  ? ifp->int_dstaddr
498 						  : ifp->int_addr);
499 			if (setsockopt(rip_sock,IPPROTO_IP,IP_DROP_MEMBERSHIP,
500 				       &m, sizeof(m)) < 0
501 			    && errno != EADDRNOTAVAIL
502 			    && !TRACEACTIONS)
503 				LOGERR("setsockopt(IP_DROP_MEMBERSHIP RIP)");
504 			if (rip_sock_mcast == ifp)
505 				rip_sock_mcast = 0;
506 		}
507 		if (ifp->int_rip_sock >= 0) {
508 			close(ifp->int_rip_sock);
509 			ifp->int_rip_sock = -1;
510 			fix_select();
511 		}
512 
513 		tot_interfaces--;
514 		if (!IS_RIP_OFF(ifp->int_state))
515 			rip_interfaces--;
516 
517 		/* Zap all routes associated with this interface.
518 		 * Assume routes just using gateways beyond this interface
519 		 * will timeout naturally, and have probably already died.
520 		 */
521 		rn_walktree(rhead, walk_bad, 0);
522 
523 		set_rdisc_mg(ifp, 0);
524 		if_bad_rdisc(ifp);
525 	}
526 
527 	free(ifp);
528 }
529 
530 
531 /* Mark an interface ill.
532  */
533 void
534 if_sick(struct interface *ifp)
535 {
536 	if (0 == (ifp->int_state & (IS_SICK | IS_BROKE))) {
537 		ifp->int_state |= IS_SICK;
538 		ifp->int_act_time = NEVER;
539 		trace_if("Chg", ifp);
540 
541 		LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
542 	}
543 }
544 
545 
546 /* Mark an interface dead.
547  */
548 void
549 if_bad(struct interface *ifp)
550 {
551 	struct interface *ifp1;
552 
553 
554 	if (ifp->int_state & IS_BROKE)
555 		return;
556 
557 	LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
558 
559 	ifp->int_state |= (IS_BROKE | IS_SICK);
560 	ifp->int_act_time = NEVER;
561 	ifp->int_query_time = NEVER;
562 	ifp->int_data.ts = now.tv_sec;
563 
564 	trace_if("Chg", ifp);
565 
566 	if (!(ifp->int_state & IS_ALIAS)) {
567 		for (ifp1 = ifnet; NULL != ifp1; ifp1 = ifp1->int_next) {
568 			if (ifp1 != ifp
569 			    && !strcmp(ifp->int_name, ifp1->int_name))
570 				if_bad(ifp1);
571 		}
572 		rn_walktree(rhead, walk_bad, 0);
573 		if_bad_rdisc(ifp);
574 	}
575 }
576 
577 
578 /* Mark an interface alive
579  */
580 int					/* 1=it was dead */
581 if_ok(struct interface *ifp,
582       const char *type)
583 {
584 	struct interface *ifp1;
585 
586 
587 	if (!(ifp->int_state & IS_BROKE)) {
588 		if (ifp->int_state & IS_SICK) {
589 			trace_act("%sinterface %s to %s working better",
590 				  type,
591 				  ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
592 			ifp->int_state &= ~IS_SICK;
593 		}
594 		return 0;
595 	}
596 
597 	msglog("%sinterface %s to %s restored",
598 	       type, ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
599 	ifp->int_state &= ~(IS_BROKE | IS_SICK);
600 	ifp->int_data.ts = 0;
601 
602 	if (!(ifp->int_state & IS_ALIAS)) {
603 		for (ifp1 = ifnet; NULL != ifp1; ifp1 = ifp1->int_next) {
604 			if (ifp1 != ifp
605 			    && !strcmp(ifp->int_name, ifp1->int_name))
606 				if_ok(ifp1, type);
607 		}
608 		if_ok_rdisc(ifp);
609 	}
610 
611 	if (ifp->int_state & IS_REMOTE) {
612 		if (!addrouteforif(ifp))
613 			return 0;
614 	}
615 	return 1;
616 }
617 
618 
619 /* disassemble routing message
620  */
621 void
622 rt_xaddrs(struct rt_addrinfo *info,
623 	  struct sockaddr *sa,
624 	  struct sockaddr *lim,
625 	  int addrs)
626 {
627 	int i;
628 #ifdef _HAVE_SA_LEN
629 	static struct sockaddr sa_zero;
630 #endif
631 #ifdef sgi
632 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) \
633 		    : sizeof(__uint64_t))
634 #else
635 #define ROUNDUP(a) RT_ROUNDUP(a)
636 #endif
637 
638 
639 	memset(info, 0, sizeof(*info));
640 	info->rti_addrs = addrs;
641 	for (i = 0; i < RTAX_MAX && sa < lim; i++) {
642 		if ((addrs & (1 << i)) == 0)
643 			continue;
644 #ifdef _HAVE_SA_LEN
645 		info->rti_info[i] = (sa->sa_len != 0) ? sa : &sa_zero;
646 		sa = (struct sockaddr *)((char*)(sa)
647 					 + ROUNDUP(sa->sa_len));
648 #else
649 		info->rti_info[i] = sa;
650 		sa = (struct sockaddr *)((char*)(sa)
651 					 + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
652 #endif
653 	}
654 }
655 
656 
657 /* Find the network interfaces which have configured themselves.
658  *	This must be done regularly, if only for extra addresses
659  *	that come and go on interfaces.
660  */
661 void
662 ifinit(void)
663 {
664 	static char *sysctl_buf;
665 	static size_t sysctl_buf_size = 0;
666 	uint complaints = 0;
667 	static u_int prev_complaints = 0;
668 #	define COMP_NOT_INET	0x001
669 #	define COMP_NOADDR	0x002
670 #	define COMP_BADADDR	0x004
671 #	define COMP_NODST	0x008
672 #	define COMP_NOBADR	0x010
673 #	define COMP_NOMASK	0x020
674 #	define COMP_DUP		0x040
675 #	define COMP_BAD_METRIC	0x080
676 #	define COMP_NETMASK	0x100
677 
678 	struct interface ifs, ifs0, *ifp, *ifp1;
679 	struct rt_entry *rt;
680 	size_t needed;
681 	int mib[6];
682 	struct if_msghdr *ifm;
683 	struct ifa_msghdr *ifam, *ifam_lim, *ifam2;
684 	int in, ierr, out, oerr;
685 	struct intnet *intnetp;
686 	struct rt_addrinfo info;
687 #ifdef SIOCGIFMETRIC
688 	struct ifreq ifr;
689 #endif
690 
691 
692 	last_ifinit = now;
693 	ifinit_timer.tv_sec = now.tv_sec + (supplier
694 					    ? CHECK_ACT_INTERVAL
695 					    : CHECK_QUIET_INTERVAL);
696 
697 	/* mark all interfaces so we can get rid of those that disappear */
698 	for (ifp = ifnet; NULL != ifp; ifp = ifp->int_next)
699 		ifp->int_state &= ~(IS_CHECKED | IS_DUP);
700 
701 	/* Fetch the interface list, without too many system calls
702 	 * since we do it repeatedly.
703 	 */
704 	mib[0] = CTL_NET;
705 	mib[1] = PF_ROUTE;
706 	mib[2] = 0;
707 	mib[3] = AF_INET;
708 	mib[4] = NET_RT_IFLIST;
709 	mib[5] = 0;
710 	for (;;) {
711 		if ((needed = sysctl_buf_size) != 0) {
712 			if (sysctl(mib, 6, sysctl_buf,&needed, 0, 0) >= 0)
713 				break;
714 			/* retry if the table grew */
715 			if (errno != ENOMEM && errno != EFAULT)
716 				BADERR(1, "ifinit: sysctl(RT_IFLIST)");
717 			free(sysctl_buf);
718 			needed = 0;
719 		}
720 		if (sysctl(mib, 6, 0, &needed, 0, 0) < 0)
721 			BADERR(1,"ifinit: sysctl(RT_IFLIST) estimate");
722 		sysctl_buf = rtmalloc(sysctl_buf_size = needed,
723 				      "ifinit sysctl");
724 	}
725 
726 	ifam_lim = (struct ifa_msghdr *)(sysctl_buf + needed);
727 	for (ifam = (struct ifa_msghdr *)sysctl_buf;
728 	     ifam < ifam_lim;
729 	     ifam = ifam2) {
730 
731 		ifam2 = (struct ifa_msghdr*)((char*)ifam + ifam->ifam_msglen);
732 
733 		if (ifam->ifam_type == RTM_IFINFO) {
734 			struct sockaddr_dl *sdl;
735 
736 			ifm = (struct if_msghdr *)ifam;
737 			/* make prototype structure for the IP aliases
738 			 */
739 			memset(&ifs0, 0, sizeof(ifs0));
740 			ifs0.int_rip_sock = -1;
741 			ifs0.int_index = ifm->ifm_index;
742 			ifs0.int_if_flags = ifm->ifm_flags;
743 			ifs0.int_state = IS_CHECKED;
744 			ifs0.int_query_time = NEVER;
745 			ifs0.int_act_time = now.tv_sec;
746 			ifs0.int_data.ts = now.tv_sec;
747 			ifs0.int_data.ipackets = ifm->ifm_data.ifi_ipackets;
748 			ifs0.int_data.ierrors = ifm->ifm_data.ifi_ierrors;
749 			ifs0.int_data.opackets = ifm->ifm_data.ifi_opackets;
750 			ifs0.int_data.oerrors = ifm->ifm_data.ifi_oerrors;
751 #ifdef sgi
752 			ifs0.int_data.odrops = ifm->ifm_data.ifi_odrops;
753 #endif
754 			sdl = (struct sockaddr_dl *)(ifm + 1);
755 			sdl->sdl_data[sdl->sdl_nlen] = 0;
756 			strncpy(ifs0.int_name, sdl->sdl_data,
757 				MIN(sizeof(ifs0.int_name), sdl->sdl_nlen));
758 			continue;
759 		}
760 		if (ifam->ifam_type != RTM_NEWADDR) {
761 			logbad(1,"ifinit: out of sync");
762 			continue;
763 		}
764 		rt_xaddrs(&info, (struct sockaddr *)(ifam+1),
765 			  (struct sockaddr *)ifam2,
766 			  ifam->ifam_addrs);
767 
768 		/* Prepare for the next address of this interface, which
769 		 * will be an alias.
770 		 * Do not output RIP or Router-Discovery packets via aliases.
771 		 */
772 		memcpy(&ifs, &ifs0, sizeof(ifs));
773 		ifs0.int_state |= (IS_ALIAS | IS_NO_RIP_OUT | IS_NO_RDISC);
774 
775 		if (INFO_IFA(&info) == 0) {
776 			if (iff_up(ifs.int_if_flags)) {
777 				if (!(prev_complaints & COMP_NOADDR))
778 					msglog("%s has no address",
779 					       ifs.int_name);
780 				complaints |= COMP_NOADDR;
781 			}
782 			continue;
783 		}
784 		if (INFO_IFA(&info)->sa_family != AF_INET) {
785 			if (iff_up(ifs.int_if_flags)) {
786 				if (!(prev_complaints & COMP_NOT_INET))
787 					trace_act("%s: not AF_INET",
788 						  ifs.int_name);
789 				complaints |= COMP_NOT_INET;
790 			}
791 			continue;
792 		}
793 
794 		ifs.int_addr = S_ADDR(INFO_IFA(&info));
795 
796 		if (ntohl(ifs.int_addr)>>24 == 0
797 		    || ntohl(ifs.int_addr)>>24 == 0xff) {
798 			if (iff_up(ifs.int_if_flags)) {
799 				if (!(prev_complaints & COMP_BADADDR))
800 					msglog("%s has a bad address",
801 					       ifs.int_name);
802 				complaints |= COMP_BADADDR;
803 			}
804 			continue;
805 		}
806 
807 		if (ifs.int_if_flags & IFF_LOOPBACK) {
808 			ifs.int_state |= IS_PASSIVE | IS_NO_RIP | IS_NO_RDISC;
809 			ifs.int_dstaddr = ifs.int_addr;
810 			ifs.int_mask = HOST_MASK;
811 			ifs.int_ripv1_mask = HOST_MASK;
812 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
813 			ifs.int_net = ntohl(ifs.int_dstaddr);
814 			if (!foundloopback) {
815 				foundloopback = 1;
816 				loopaddr = ifs.int_addr;
817 				loop_rts.rts_gate = loopaddr;
818 				loop_rts.rts_router = loopaddr;
819 			}
820 
821 		} else if (ifs.int_if_flags & IFF_POINTOPOINT) {
822 			if (INFO_BRD(&info) == 0
823 			    || INFO_BRD(&info)->sa_family != AF_INET) {
824 				if (iff_up(ifs.int_if_flags)) {
825 					if (!(prev_complaints & COMP_NODST))
826 						msglog("%s has a bad"
827 						       " destination address",
828 						       ifs.int_name);
829 					complaints |= COMP_NODST;
830 				}
831 				continue;
832 			}
833 			ifs.int_dstaddr = S_ADDR(INFO_BRD(&info));
834 			if (ntohl(ifs.int_dstaddr)>>24 == 0
835 			    || ntohl(ifs.int_dstaddr)>>24 == 0xff) {
836 				if (iff_up(ifs.int_if_flags)) {
837 					if (!(prev_complaints & COMP_NODST))
838 						msglog("%s has a bad"
839 						       " destination address",
840 						       ifs.int_name);
841 					complaints |= COMP_NODST;
842 				}
843 				continue;
844 			}
845 			ifs.int_mask = HOST_MASK;
846 			ifs.int_ripv1_mask = ntohl(S_ADDR(INFO_MASK(&info)));
847 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
848 			ifs.int_net = ntohl(ifs.int_dstaddr);
849 
850 		}  else {
851 			if (INFO_MASK(&info) == 0) {
852 				if (iff_up(ifs.int_if_flags)) {
853 					if (!(prev_complaints & COMP_NOMASK))
854 						msglog("%s has no netmask",
855 						       ifs.int_name);
856 					complaints |= COMP_NOMASK;
857 				}
858 				continue;
859 			}
860 			ifs.int_dstaddr = ifs.int_addr;
861 			ifs.int_mask = ntohl(S_ADDR(INFO_MASK(&info)));
862 			ifs.int_ripv1_mask = ifs.int_mask;
863 			ifs.int_std_mask = std_mask(ifs.int_addr);
864 			ifs.int_net = ntohl(ifs.int_addr) & ifs.int_mask;
865 			if (ifs.int_mask != ifs.int_std_mask)
866 				ifs.int_state |= IS_SUBNET;
867 
868 			if (ifs.int_if_flags & IFF_BROADCAST) {
869 				if (INFO_BRD(&info) == 0) {
870 					if (iff_up(ifs.int_if_flags)) {
871 					    if (!(prev_complaints
872 						  & COMP_NOBADR))
873 						msglog("%s has"
874 						       "no broadcast address",
875 						       ifs.int_name);
876 					    complaints |= COMP_NOBADR;
877 					}
878 					continue;
879 				}
880 				ifs.int_brdaddr = S_ADDR(INFO_BRD(&info));
881 			}
882 		}
883 		ifs.int_std_net = ifs.int_net & ifs.int_std_mask;
884 		ifs.int_std_addr = htonl(ifs.int_std_net);
885 
886 		/* Use a minimum metric of one.  Treat the interface metric
887 		 * (default 0) as an increment to the hop count of one.
888 		 *
889 		 * The metric obtained from the routing socket dump of
890 		 * interface addresses is wrong.  It is not set by the
891 		 * SIOCSIFMETRIC ioctl.
892 		 */
893 #ifdef SIOCGIFMETRIC
894 		strncpy(ifr.ifr_name, ifs.int_name, sizeof(ifr.ifr_name));
895 		if (ioctl(rt_sock, SIOCGIFMETRIC, &ifr) < 0) {
896 			DBGERR(1, "ioctl(SIOCGIFMETRIC)");
897 			ifs.int_metric = 0;
898 		} else {
899 			ifs.int_metric = ifr.ifr_metric;
900 		}
901 #else
902 		ifs.int_metric = ifam->ifam_metric;
903 #endif
904 		if (ifs.int_metric > HOPCNT_INFINITY) {
905 			ifs.int_metric = 0;
906 			if (!(prev_complaints & COMP_BAD_METRIC)
907 			    && iff_up(ifs.int_if_flags)) {
908 				complaints |= COMP_BAD_METRIC;
909 				msglog("%s has a metric of %d",
910 				       ifs.int_name, ifs.int_metric);
911 			}
912 		}
913 
914 		/* See if this is a familiar interface.
915 		 * If so, stop worrying about it if it is the same.
916 		 * Start it over if it now is to somewhere else, as happens
917 		 * frequently with PPP and SLIP.
918 		 */
919 		ifp = ifwithname(ifs.int_name, ((ifs.int_state & IS_ALIAS)
920 						? ifs.int_addr
921 						: 0));
922 		if (ifp != NULL) {
923 			ifp->int_state |= IS_CHECKED;
924 
925 			if (0 != ((ifp->int_if_flags ^ ifs.int_if_flags)
926 				  & (IFF_BROADCAST
927 				     | IFF_LOOPBACK
928 				     | IFF_POINTOPOINT
929 				     | IFF_MULTICAST))
930 			    || 0 != ((ifp->int_state ^ ifs.int_state)
931 				     & IS_ALIAS)
932 			    || ifp->int_addr != ifs.int_addr
933 			    || ifp->int_brdaddr != ifs.int_brdaddr
934 			    || ifp->int_dstaddr != ifs.int_dstaddr
935 			    || ifp->int_mask != ifs.int_mask
936 			    || ifp->int_metric != ifs.int_metric) {
937 				/* Forget old information about
938 				 * a changed interface.
939 				 */
940 				trace_act("interface %s has changed",
941 					  ifp->int_name);
942 				ifdel(ifp);
943 				ifp = NULL;
944 			}
945 		}
946 
947 		if (ifp != NULL) {
948 			/* The primary representative of an alias worries
949 			 * about how things are working.
950 			 */
951 			if (ifp->int_state & IS_ALIAS)
952 				continue;
953 
954 			/* note interfaces that have been turned off
955 			 */
956 			if (!iff_up(ifs.int_if_flags)) {
957 				if (iff_up(ifp->int_if_flags)) {
958 					msglog("interface %s to %s turned off",
959 					       ifp->int_name,
960 					       naddr_ntoa(ifp->int_dstaddr));
961 					if_bad(ifp);
962 					ifp->int_if_flags &= ~IFF_UP;
963 				} else if (now.tv_sec>(ifp->int_data.ts
964 						       + CHECK_BAD_INTERVAL)) {
965 					trace_act("interface %s has been off"
966 						  " %ld seconds; forget it",
967 						  ifp->int_name,
968 						  now.tv_sec-ifp->int_data.ts);
969 					ifdel(ifp);
970 				}
971 				continue;
972 			}
973 			/* or that were off and are now ok */
974 			if (!iff_up(ifp->int_if_flags)) {
975 				ifp->int_if_flags |= IFF_UP;
976 				if_ok(ifp, "");
977 			}
978 
979 			/* If it has been long enough,
980 			 * see if the interface is broken.
981 			 */
982 			if (now.tv_sec < ifp->int_data.ts+CHECK_BAD_INTERVAL)
983 				continue;
984 
985 			in = ifs.int_data.ipackets - ifp->int_data.ipackets;
986 			ierr = ifs.int_data.ierrors - ifp->int_data.ierrors;
987 			out = ifs.int_data.opackets - ifp->int_data.opackets;
988 			oerr = ifs.int_data.oerrors - ifp->int_data.oerrors;
989 #ifdef sgi
990 			/* Through at least IRIX 6.2, PPP and SLIP
991 			 * count packets dropped by the filters.
992 			 * But FDDI rings stuck non-operational count
993 			 * dropped packets as they wait for improvement.
994 			 */
995 			if (!(ifp->int_if_flags & IFF_POINTOPOINT))
996 				oerr += (ifs.int_data.odrops
997 					 - ifp->int_data.odrops);
998 #endif
999 			/* If the interface just awoke, restart the counters.
1000 			 */
1001 			if (ifp->int_data.ts == 0) {
1002 				ifp->int_data = ifs.int_data;
1003 				continue;
1004 			}
1005 			ifp->int_data = ifs.int_data;
1006 
1007 			/* Withhold judgment when the short error
1008 			 * counters wrap or the interface is reset.
1009 			 */
1010 			if (ierr < 0 || in < 0 || oerr < 0 || out < 0) {
1011 				LIM_SEC(ifinit_timer,
1012 					now.tv_sec+CHECK_BAD_INTERVAL);
1013 				continue;
1014 			}
1015 
1016 			/* Withhold judgement when there is no traffic
1017 			 */
1018 			if (in == 0 && out == 0 && ierr == 0 && oerr == 0)
1019 				continue;
1020 
1021 			/* It is bad if input or output is not working.
1022 			 * Require presistent problems before marking it dead.
1023 			 */
1024 			if ((in <= ierr && ierr > 0)
1025 			    || (out <= oerr && oerr > 0)) {
1026 				if (!(ifp->int_state & IS_SICK)) {
1027 					trace_act("interface %s to %s"
1028 						  " sick: in=%d ierr=%d"
1029 						  " out=%d oerr=%d",
1030 						  ifp->int_name,
1031 						  naddr_ntoa(ifp->int_dstaddr),
1032 						  in, ierr, out, oerr);
1033 					if_sick(ifp);
1034 					continue;
1035 				}
1036 				if (!(ifp->int_state & IS_BROKE)) {
1037 					msglog("interface %s to %s broken:"
1038 					       " in=%d ierr=%d out=%d oerr=%d",
1039 					       ifp->int_name,
1040 					       naddr_ntoa(ifp->int_dstaddr),
1041 					       in, ierr, out, oerr);
1042 					if_bad(ifp);
1043 				}
1044 				continue;
1045 			}
1046 
1047 			/* otherwise, it is active and healthy
1048 			 */
1049 			ifp->int_act_time = now.tv_sec;
1050 			if_ok(ifp, "");
1051 			continue;
1052 		}
1053 
1054 		/* This is a new interface.
1055 		 * If it is dead, forget it.
1056 		 */
1057 		if (!iff_up(ifs.int_if_flags))
1058 			continue;
1059 
1060 		/* If it duplicates an existing interface,
1061 		 * complain about it, mark the other one
1062 		 * duplicated, and forget this one.
1063 		 */
1064 		ifp = check_dup(ifs.int_addr,ifs.int_dstaddr,ifs.int_mask,
1065 				ifs.int_if_flags);
1066 		if (ifp != NULL) {
1067 			/* Ignore duplicates of itself, caused by having
1068 			 * IP aliases on the same network.
1069 			 */
1070 			if (!strcmp(ifp->int_name, ifs.int_name))
1071 				continue;
1072 
1073 			if (!(prev_complaints & COMP_DUP)) {
1074 				complaints |= COMP_DUP;
1075 				msglog("%s (%s%s%s) is duplicated by"
1076 				       " %s (%s%s%s)",
1077 				       ifs.int_name,
1078 				       addrname(ifs.int_addr,ifs.int_mask,1),
1079 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1080 					? "-->" : ""),
1081 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1082 					? naddr_ntoa(ifs.int_dstaddr) : ""),
1083 				       ifp->int_name,
1084 				       addrname(ifp->int_addr,ifp->int_mask,1),
1085 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1086 					? "-->" : ""),
1087 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1088 					? naddr_ntoa(ifp->int_dstaddr) : ""));
1089 			}
1090 			ifp->int_state |= IS_DUP;
1091 			continue;
1092 		}
1093 
1094 		if (0 == (ifs.int_if_flags & (IFF_POINTOPOINT | IFF_BROADCAST))
1095 		    && !(ifs.int_state & IS_PASSIVE)) {
1096 			trace_act("%s is neither broadcast, point-to-point,"
1097 				  " nor loopback",
1098 				  ifs.int_name);
1099 			if (!(ifs.int_state & IFF_MULTICAST))
1100 				ifs.int_state |= IS_NO_RDISC;
1101 		}
1102 
1103 
1104 		/* It is new and ok.   Add it to the list of interfaces
1105 		 */
1106 		ifp = (struct interface *)rtmalloc(sizeof(*ifp), "ifinit ifp");
1107 		memcpy(ifp, &ifs, sizeof(*ifp));
1108 		get_parms(ifp);
1109 		if_link(ifp);
1110 		trace_if("Add", ifp);
1111 
1112 		/* Notice likely bad netmask.
1113 		 */
1114 		if (!(prev_complaints & COMP_NETMASK)
1115 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
1116 		    && ifp->int_addr != RIP_DEFAULT) {
1117 			for (ifp1 = ifnet; NULL != ifp1; ifp1 = ifp1->int_next) {
1118 				if (ifp1->int_mask == ifp->int_mask)
1119 					continue;
1120 				if (ifp1->int_if_flags & IFF_POINTOPOINT)
1121 					continue;
1122 				if (ifp1->int_dstaddr == RIP_DEFAULT)
1123 					continue;
1124 				/* ignore aliases on the right network */
1125 				if (!strcmp(ifp->int_name, ifp1->int_name))
1126 					continue;
1127 				if (on_net(ifp->int_dstaddr,
1128 					   ifp1->int_net, ifp1->int_mask)
1129 				    || on_net(ifp1->int_dstaddr,
1130 					      ifp->int_net, ifp->int_mask)) {
1131 					msglog("possible netmask problem"
1132 					       " between %s:%s and %s:%s",
1133 					       ifp->int_name,
1134 					       addrname(htonl(ifp->int_net),
1135 							ifp->int_mask, 1),
1136 					       ifp1->int_name,
1137 					       addrname(htonl(ifp1->int_net),
1138 							ifp1->int_mask, 1));
1139 					complaints |= COMP_NETMASK;
1140 				}
1141 			}
1142 		}
1143 
1144 		if (!(ifp->int_state & IS_ALIAS)) {
1145 			/* Count the # of directly connected networks.
1146 			 */
1147 			if (!(ifp->int_if_flags & IFF_LOOPBACK))
1148 				tot_interfaces++;
1149 			if (!IS_RIP_OFF(ifp->int_state))
1150 				rip_interfaces++;
1151 
1152 			/* turn on router discovery and RIP If needed */
1153 			if_ok_rdisc(ifp);
1154 			rip_on(ifp);
1155 		}
1156 	}
1157 
1158 	/* If we are multi-homed and have at least two interfaces
1159 	 * listening to RIP, then output by default.
1160 	 */
1161 	if (!supplier_set && rip_interfaces > 1)
1162 		set_supplier();
1163 
1164 	/* If we are multi-homed, optionally advertise a route to
1165 	 * our main address.
1166 	 */
1167 	if (advertise_mhome
1168 	    || (tot_interfaces > 1
1169 		&& mhome
1170 		&& (ifp = ifwithaddr(myaddr, 0, 0)) != NULL
1171 		&& foundloopback)) {
1172 		advertise_mhome = 1;
1173 		rt = rtget(myaddr, HOST_MASK);
1174 		if (rt != NULL) {
1175 			if (rt->rt_ifp != ifp
1176 			    || rt->rt_router != loopaddr) {
1177 				rtdelete(rt);
1178 				rt = NULL;
1179 			} else {
1180 				loop_rts.rts_ifp = ifp;
1181 				loop_rts.rts_metric = 0;
1182 				loop_rts.rts_time = rt->rt_time;
1183 				rtchange(rt, rt->rt_state | RS_MHOME,
1184 					 &loop_rts, 0);
1185 			}
1186 		}
1187 		if (rt == NULL) {
1188 			loop_rts.rts_ifp = ifp;
1189 			loop_rts.rts_metric = 0;
1190 			rtadd(myaddr, HOST_MASK, RS_MHOME, &loop_rts);
1191 		}
1192 	}
1193 
1194 	for (ifp = ifnet; ifp != NULL; ifp = ifp1) {
1195 		ifp1 = ifp->int_next;	/* because we may delete it */
1196 
1197 		/* Forget any interfaces that have disappeared.
1198 		 */
1199 		if (!(ifp->int_state & (IS_CHECKED | IS_REMOTE))) {
1200 			trace_act("interface %s has disappeared",
1201 				  ifp->int_name);
1202 			ifdel(ifp);
1203 			continue;
1204 		}
1205 
1206 		if ((ifp->int_state & IS_BROKE)
1207 		    && !(ifp->int_state & IS_PASSIVE))
1208 			LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
1209 
1210 		/* If we ever have a RIPv1 interface, assume we always will.
1211 		 * It might come back if it ever goes away.
1212 		 */
1213 		if (!(ifp->int_state & IS_NO_RIPV1_OUT) && supplier)
1214 			have_ripv1_out = 1;
1215 		if (!(ifp->int_state & IS_NO_RIPV1_IN))
1216 			have_ripv1_in = 1;
1217 	}
1218 
1219 	for (ifp = ifnet; ifp != NULL; ifp = ifp->int_next) {
1220 		/* Ensure there is always a network route for interfaces,
1221 		 * after any dead interfaces have been deleted, which
1222 		 * might affect routes for point-to-point links.
1223 		 */
1224 		if (!addrouteforif(ifp))
1225 			continue;
1226 
1227 		/* Add routes to the local end of point-to-point interfaces
1228 		 * using loopback.
1229 		 */
1230 		if ((ifp->int_if_flags & IFF_POINTOPOINT)
1231 		    && !(ifp->int_state & IS_REMOTE)
1232 		    && foundloopback) {
1233 			/* Delete any routes to the network address through
1234 			 * foreign routers. Remove even static routes.
1235 			 */
1236 			del_static(ifp->int_addr, HOST_MASK, 0, 0);
1237 			rt = rtget(ifp->int_addr, HOST_MASK);
1238 			if (rt != NULL && rt->rt_router != loopaddr) {
1239 				rtdelete(rt);
1240 				rt = NULL;
1241 			}
1242 			if (rt != NULL) {
1243 				if (!(rt->rt_state & RS_LOCAL)
1244 				    || rt->rt_metric > ifp->int_metric) {
1245 					ifp1 = ifp;
1246 				} else {
1247 					ifp1 = rt->rt_ifp;
1248 				}
1249 				loop_rts.rts_ifp = ifp1;
1250 				loop_rts.rts_metric = 0;
1251 				loop_rts.rts_time = rt->rt_time;
1252 				rtchange(rt, ((rt->rt_state & ~RS_NET_SYN)
1253 					      | (RS_IF|RS_LOCAL)),
1254 					 &loop_rts, 0);
1255 			} else {
1256 				loop_rts.rts_ifp = ifp;
1257 				loop_rts.rts_metric = 0;
1258 				rtadd(ifp->int_addr, HOST_MASK,
1259 				      (RS_IF | RS_LOCAL), &loop_rts);
1260 			}
1261 		}
1262 	}
1263 
1264 	/* add the authority routes */
1265 	for (intnetp = intnets; intnetp!=NULL; intnetp = intnetp->intnet_next) {
1266 		rt = rtget(intnetp->intnet_addr, intnetp->intnet_mask);
1267 		if (rt != NULL
1268 		    && !(rt->rt_state & RS_NO_NET_SYN)
1269 		    && !(rt->rt_state & RS_NET_INT)) {
1270 			rtdelete(rt);
1271 			rt = NULL;
1272 		}
1273 		if (rt == NULL) {
1274 			loop_rts.rts_ifp = 0;
1275 			loop_rts.rts_metric = intnetp->intnet_metric-1;
1276 			rtadd(intnetp->intnet_addr, intnetp->intnet_mask,
1277 			      RS_NET_SYN | RS_NET_INT, &loop_rts);
1278 		}
1279 	}
1280 
1281 	prev_complaints = complaints;
1282 }
1283 
1284 
1285 static void
1286 check_net_syn(struct interface *ifp)
1287 {
1288 	struct rt_entry *rt;
1289 	static struct rt_spare new;
1290 
1291 
1292 	/* Turn on the need to automatically synthesize a network route
1293 	 * for this interface only if we are running RIPv1 on some other
1294 	 * interface that is on a different class-A,B,or C network.
1295 	 */
1296 	if (have_ripv1_out || have_ripv1_in) {
1297 		ifp->int_state |= IS_NEED_NET_SYN;
1298 		rt = rtget(ifp->int_std_addr, ifp->int_std_mask);
1299 		if (rt != NULL
1300 		    && 0 == (rt->rt_state & RS_NO_NET_SYN)
1301 		    && (!(rt->rt_state & RS_NET_SYN)
1302 			|| rt->rt_metric > ifp->int_metric)) {
1303 			rtdelete(rt);
1304 			rt = NULL;
1305 		}
1306 		if (rt == NULL) {
1307 			new.rts_ifp = ifp;
1308 			new.rts_gate = ifp->int_addr;
1309 			new.rts_router = ifp->int_addr;
1310 			new.rts_metric = ifp->int_metric;
1311 			rtadd(ifp->int_std_addr, ifp->int_std_mask,
1312 			      RS_NET_SYN, &new);
1313 		}
1314 
1315 	} else {
1316 		ifp->int_state &= ~IS_NEED_NET_SYN;
1317 
1318 		rt = rtget(ifp->int_std_addr,
1319 			   ifp->int_std_mask);
1320 		if (rt != NULL
1321 		    && (rt->rt_state & RS_NET_SYN)
1322 		    && rt->rt_ifp == ifp)
1323 			rtbad_sub(rt);
1324 	}
1325 }
1326 
1327 
1328 /* Add route for interface if not currently installed.
1329  * Create route to other end if a point-to-point link,
1330  * otherwise a route to this (sub)network.
1331  */
1332 int					/* 0=bad interface */
1333 addrouteforif(struct interface *ifp)
1334 {
1335 	struct rt_entry *rt;
1336 	static struct rt_spare new;
1337 	naddr dst;
1338 
1339 
1340 	/* skip sick interfaces
1341 	 */
1342 	if (ifp->int_state & IS_BROKE)
1343 		return 0;
1344 
1345 	/* If the interface on a subnet, then install a RIPv1 route to
1346 	 * the network as well (unless it is sick).
1347 	 */
1348 	if (ifp->int_state & IS_SUBNET)
1349 		check_net_syn(ifp);
1350 
1351 	dst = (0 != (ifp->int_if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK))
1352 	       ? ifp->int_dstaddr
1353 	       : htonl(ifp->int_net));
1354 
1355 	new.rts_ifp = ifp;
1356 	new.rts_router = ifp->int_addr;
1357 	new.rts_gate = ifp->int_addr;
1358 	new.rts_metric = ifp->int_metric;
1359 	new.rts_time = now.tv_sec;
1360 
1361 	/* If we are going to send packets to the gateway,
1362 	 * it must be reachable using our physical interfaces
1363 	 */
1364 	if ((ifp->int_state & IS_REMOTE)
1365 	    && !(ifp->int_state & IS_EXTERNAL)
1366 	    && !check_remote(ifp))
1367 		return 0;
1368 
1369 	/* We are finished if the correct main interface route exists.
1370 	 * The right route must be for the right interface, not synthesized
1371 	 * from a subnet, be a "gateway" or not as appropriate, and so forth.
1372 	 */
1373 	del_static(dst, ifp->int_mask, 0, 0);
1374 	rt = rtget(dst, ifp->int_mask);
1375 	if (rt != NULL) {
1376 		if ((rt->rt_ifp != ifp
1377 		     || rt->rt_router != ifp->int_addr)
1378 		    && (!(ifp->int_state & IS_DUP)
1379 			|| rt->rt_ifp == 0
1380 			|| (rt->rt_ifp->int_state & IS_BROKE))) {
1381 			rtdelete(rt);
1382 			rt = NULL;
1383 		} else {
1384 			rtchange(rt, ((rt->rt_state | RS_IF)
1385 				      & ~(RS_NET_SYN | RS_LOCAL)),
1386 				 &new, 0);
1387 		}
1388 	}
1389 	if (rt == NULL) {
1390 		if (ifp->int_transitions++ > 0)
1391 			trace_act("re-install interface %s",
1392 				  ifp->int_name);
1393 
1394 		rtadd(dst, ifp->int_mask, RS_IF, &new);
1395 	}
1396 
1397 	return 1;
1398 }
1399