xref: /freebsd/sbin/routed/if.c (revision 69c9999d0ca45b210e75706ab4952ad5a33ce6ec)
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. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgment:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * $FreeBSD$
34  */
35 
36 #include "defs.h"
37 #include "pathnames.h"
38 
39 #if !defined(sgi) && !defined(__NetBSD__)
40 static char sccsid[] __attribute__((unused)) = "@(#)if.c	8.1 (Berkeley) 6/5/93";
41 #elif defined(__NetBSD__)
42 #include <sys/cdefs.h>
43 __RCSID("$NetBSD$");
44 #endif
45 #ident "$FreeBSD$"
46 
47 struct interface *ifnet;		/* all interfaces */
48 
49 /* hash table for all interfaces, big enough to tolerate ridiculous
50  * numbers of IP aliases.  Crazy numbers of aliases such as 7000
51  * still will not do well, but not just in looking up interfaces
52  * by name or address.
53  */
54 #define AHASH_LEN 211			/* must be prime */
55 #define AHASH(a) &ahash_tbl[(a)%AHASH_LEN]
56 struct interface *ahash_tbl[AHASH_LEN];
57 
58 #define BHASH_LEN 211			/* must be prime */
59 #define BHASH(a) &bhash_tbl[(a)%BHASH_LEN]
60 struct interface *bhash_tbl[BHASH_LEN];
61 
62 struct interface *remote_if;		/* remote interfaces */
63 
64 /* hash for physical interface names.
65  * Assume there are never more 100 or 200 real interfaces, and that
66  * aliases are put on the end of the hash chains.
67  */
68 #define NHASH_LEN 97
69 struct interface *nhash_tbl[NHASH_LEN];
70 
71 int	tot_interfaces;			/* # of remote and local interfaces */
72 int	rip_interfaces;			/* # of interfaces doing RIP */
73 int	foundloopback;			/* valid flag for loopaddr */
74 naddr	loopaddr;			/* our address on loopback */
75 struct	rt_spare loop_rts;
76 
77 struct timeval ifinit_timer;
78 static struct timeval last_ifinit;
79 #define IF_RESCAN_DELAY() (last_ifinit.tv_sec == now.tv_sec		\
80 			   && last_ifinit.tv_usec == now.tv_usec	\
81 			   && timercmp(&ifinit_timer, &now, >))
82 
83 int	have_ripv1_out;			/* have a RIPv1 interface */
84 int	have_ripv1_in;
85 
86 
87 static struct interface**
88 nhash(char *p)
89 {
90 	u_int i;
91 
92 	for (i = 0; *p != '\0'; p++) {
93 		i = ((i<<1) & 0x7fffffff) | ((i>>31) & 1);
94 		i ^= *p;
95 	}
96 	return &nhash_tbl[i % NHASH_LEN];
97 }
98 
99 
100 /* Link a new interface into the lists and hash tables.
101  */
102 void
103 if_link(struct interface *ifp)
104 {
105 	struct interface **hifp;
106 
107 	ifp->int_prev = &ifnet;
108 	ifp->int_next = ifnet;
109 	if (ifnet != 0)
110 		ifnet->int_prev = &ifp->int_next;
111 	ifnet = ifp;
112 
113 	hifp = AHASH(ifp->int_addr);
114 	ifp->int_ahash_prev = hifp;
115 	if ((ifp->int_ahash = *hifp) != 0)
116 		(*hifp)->int_ahash_prev = &ifp->int_ahash;
117 	*hifp = ifp;
118 
119 	if (ifp->int_if_flags & IFF_BROADCAST) {
120 		hifp = BHASH(ifp->int_brdaddr);
121 		ifp->int_bhash_prev = hifp;
122 		if ((ifp->int_bhash = *hifp) != 0)
123 			(*hifp)->int_bhash_prev = &ifp->int_bhash;
124 		*hifp = ifp;
125 	}
126 
127 	if (ifp->int_state & IS_REMOTE) {
128 		ifp->int_rlink_prev = &remote_if;
129 		ifp->int_rlink = remote_if;
130 		if (remote_if != 0)
131 			remote_if->int_rlink_prev = &ifp->int_rlink;
132 		remote_if = ifp;
133 	}
134 
135 	hifp = nhash(ifp->int_name);
136 	if (ifp->int_state & IS_ALIAS) {
137 		/* put aliases on the end of the hash chain */
138 		while (*hifp != 0)
139 			hifp = &(*hifp)->int_nhash;
140 	}
141 	ifp->int_nhash_prev = hifp;
142 	if ((ifp->int_nhash = *hifp) != 0)
143 		(*hifp)->int_nhash_prev = &ifp->int_nhash;
144 	*hifp = ifp;
145 }
146 
147 
148 /* Find the interface with an address
149  */
150 struct interface *
151 ifwithaddr(naddr addr,
152 	   int	bcast,			/* notice IFF_BROADCAST address */
153 	   int	remote)			/* include IS_REMOTE interfaces */
154 {
155 	struct interface *ifp, *possible = 0;
156 
157 	remote = (remote == 0) ? IS_REMOTE : 0;
158 
159 	for (ifp = *AHASH(addr); ifp; ifp = ifp->int_ahash) {
160 		if (ifp->int_addr != addr)
161 			continue;
162 		if ((ifp->int_state & remote) != 0)
163 			continue;
164 		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
165 			return ifp;
166 		possible = ifp;
167 	}
168 
169 	if (possible || !bcast)
170 		return possible;
171 
172 	for (ifp = *BHASH(addr); ifp; ifp = ifp->int_bhash) {
173 		if (ifp->int_brdaddr != addr)
174 			continue;
175 		if ((ifp->int_state & remote) != 0)
176 			continue;
177 		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
178 			return ifp;
179 		possible = ifp;
180 	}
181 
182 	return possible;
183 }
184 
185 
186 /* find the interface with a name
187  */
188 struct interface *
189 ifwithname(char *name,			/* "ec0" or whatever */
190 	   naddr addr)			/* 0 or network address */
191 {
192 	struct interface *ifp;
193 
194 	for (;;) {
195 		for (ifp = *nhash(name); ifp != 0; ifp = ifp->int_nhash) {
196 			/* If the network address is not specified,
197 			 * ignore any alias interfaces.  Otherwise, look
198 			 * for the interface with the target name and address.
199 			 */
200 			if (!strcmp(ifp->int_name, name)
201 			    && ((addr == 0 && !(ifp->int_state & IS_ALIAS))
202 				|| (ifp->int_addr == addr)))
203 				return ifp;
204 		}
205 
206 		/* If there is no known interface, maybe there is a
207 		 * new interface.  So just once look for new interfaces.
208 		 */
209 		if (IF_RESCAN_DELAY())
210 			return 0;
211 		ifinit();
212 	}
213 }
214 
215 
216 struct interface *
217 ifwithindex(u_short index,
218 	    int rescan_ok)
219 {
220 	struct interface *ifp;
221 
222 	for (;;) {
223 		for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
224 			if (ifp->int_index == index)
225 				return ifp;
226 		}
227 
228 		/* If there is no known interface, maybe there is a
229 		 * new interface.  So just once look for new interfaces.
230 		 */
231 		if (!rescan_ok
232 		    || IF_RESCAN_DELAY())
233 			return 0;
234 		ifinit();
235 	}
236 }
237 
238 
239 /* Find an interface from which the specified address
240  * should have come from.  Used for figuring out which
241  * interface a packet came in on.
242  */
243 struct interface *
244 iflookup(naddr addr)
245 {
246 	struct interface *ifp, *maybe;
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
271 		    || IF_RESCAN_DELAY())
272 			return maybe;
273 
274 		/* If there is no known interface, maybe there is a
275 		 * new interface.  So just once look for new interfaces.
276 		 */
277 		ifinit();
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 	addr = 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 an IP address looks reasonable as a destination.
371  */
372 int					/* 0=bad */
373 check_dst(naddr addr)
374 {
375 	addr = 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 			m.imr_interface.s_addr = ((ifp->int_if_flags
502 						   & IFF_POINTOPOINT)
503 						  ? ifp->int_dstaddr
504 						  : ifp->int_addr);
505 			if (setsockopt(rip_sock,IPPROTO_IP,IP_DROP_MEMBERSHIP,
506 				       &m, sizeof(m)) < 0
507 			    && errno != EADDRNOTAVAIL
508 			    && !TRACEACTIONS)
509 				LOGERR("setsockopt(IP_DROP_MEMBERSHIP RIP)");
510 			if (rip_sock_mcast == ifp)
511 				rip_sock_mcast = 0;
512 		}
513 		if (ifp->int_rip_sock >= 0) {
514 			(void)close(ifp->int_rip_sock);
515 			ifp->int_rip_sock = -1;
516 			fix_select();
517 		}
518 
519 		tot_interfaces--;
520 		if (!IS_RIP_OFF(ifp->int_state))
521 			rip_interfaces--;
522 
523 		/* Zap all routes associated with this interface.
524 		 * Assume routes just using gateways beyond this interface
525 		 * will timeout naturally, and have probably already died.
526 		 */
527 		(void)rn_walktree(rhead, walk_bad, 0);
528 
529 		set_rdisc_mg(ifp, 0);
530 		if_bad_rdisc(ifp);
531 	}
532 
533 	free(ifp);
534 }
535 
536 
537 /* Mark an interface ill.
538  */
539 void
540 if_sick(struct interface *ifp)
541 {
542 	if (0 == (ifp->int_state & (IS_SICK | IS_BROKE))) {
543 		ifp->int_state |= IS_SICK;
544 		ifp->int_act_time = NEVER;
545 		trace_if("Chg", ifp);
546 
547 		LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
548 	}
549 }
550 
551 
552 /* Mark an interface dead.
553  */
554 void
555 if_bad(struct interface *ifp)
556 {
557 	struct interface *ifp1;
558 
559 
560 	if (ifp->int_state & IS_BROKE)
561 		return;
562 
563 	LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
564 
565 	ifp->int_state |= (IS_BROKE | IS_SICK);
566 	ifp->int_act_time = NEVER;
567 	ifp->int_query_time = NEVER;
568 	ifp->int_data.ts = now.tv_sec;
569 
570 	trace_if("Chg", ifp);
571 
572 	if (!(ifp->int_state & IS_ALIAS)) {
573 		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
574 			if (ifp1 != ifp
575 			    && !strcmp(ifp->int_name, ifp1->int_name))
576 				if_bad(ifp1);
577 		}
578 		(void)rn_walktree(rhead, walk_bad, 0);
579 		if_bad_rdisc(ifp);
580 	}
581 }
582 
583 
584 /* Mark an interface alive
585  */
586 int					/* 1=it was dead */
587 if_ok(struct interface *ifp,
588       const char *type)
589 {
590 	struct interface *ifp1;
591 
592 
593 	if (!(ifp->int_state & IS_BROKE)) {
594 		if (ifp->int_state & IS_SICK) {
595 			trace_act("%sinterface %s to %s working better",
596 				  type,
597 				  ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
598 			ifp->int_state &= ~IS_SICK;
599 		}
600 		return 0;
601 	}
602 
603 	msglog("%sinterface %s to %s restored",
604 	       type, ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
605 	ifp->int_state &= ~(IS_BROKE | IS_SICK);
606 	ifp->int_data.ts = 0;
607 
608 	if (!(ifp->int_state & IS_ALIAS)) {
609 		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
610 			if (ifp1 != ifp
611 			    && !strcmp(ifp->int_name, ifp1->int_name))
612 				if_ok(ifp1, type);
613 		}
614 		if_ok_rdisc(ifp);
615 	}
616 
617 	if (ifp->int_state & IS_REMOTE) {
618 		if (!addrouteforif(ifp))
619 			return 0;
620 	}
621 	return 1;
622 }
623 
624 
625 /* disassemble routing message
626  */
627 void
628 rt_xaddrs(struct rt_addrinfo *info,
629 	  struct sockaddr *sa,
630 	  struct sockaddr *lim,
631 	  int addrs)
632 {
633 	int i;
634 #ifdef _HAVE_SA_LEN
635 	static struct sockaddr sa_zero;
636 #endif
637 #ifdef sgi
638 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) \
639 		    : sizeof(__uint64_t))
640 #else
641 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) \
642 		    : sizeof(long))
643 #endif
644 
645 
646 	memset(info, 0, sizeof(*info));
647 	info->rti_addrs = addrs;
648 	for (i = 0; i < RTAX_MAX && sa < lim; i++) {
649 		if ((addrs & (1 << i)) == 0)
650 			continue;
651 #ifdef _HAVE_SA_LEN
652 		info->rti_info[i] = (sa->sa_len != 0) ? sa : &sa_zero;
653 		sa = (struct sockaddr *)((char*)(sa)
654 					 + ROUNDUP(sa->sa_len));
655 #else
656 		info->rti_info[i] = sa;
657 		sa = (struct sockaddr *)((char*)(sa)
658 					 + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
659 #endif
660 	}
661 }
662 
663 
664 /* Find the network interfaces which have configured themselves.
665  *	This must be done regularly, if only for extra addresses
666  *	that come and go on interfaces.
667  */
668 void
669 ifinit(void)
670 {
671 	static char *sysctl_buf;
672 	static size_t sysctl_buf_size = 0;
673 	uint complaints = 0;
674 	static u_int prev_complaints = 0;
675 #	define COMP_NOT_INET	0x001
676 #	define COMP_NOADDR	0x002
677 #	define COMP_BADADDR	0x004
678 #	define COMP_NODST	0x008
679 #	define COMP_NOBADR	0x010
680 #	define COMP_NOMASK	0x020
681 #	define COMP_DUP		0x040
682 #	define COMP_BAD_METRIC	0x080
683 #	define COMP_NETMASK	0x100
684 
685 	struct interface ifs, ifs0, *ifp, *ifp1;
686 	struct rt_entry *rt;
687 	size_t needed;
688 	int mib[6];
689 	struct if_msghdr *ifm;
690 	struct ifa_msghdr *ifam, *ifam_lim, *ifam2;
691 	int in, ierr, out, oerr;
692 	struct intnet *intnetp;
693 	struct rt_addrinfo info;
694 #ifdef SIOCGIFMETRIC
695 	struct ifreq ifr;
696 #endif
697 
698 
699 	last_ifinit = now;
700 	ifinit_timer.tv_sec = now.tv_sec + (supplier
701 					    ? CHECK_ACT_INTERVAL
702 					    : CHECK_QUIET_INTERVAL);
703 
704 	/* mark all interfaces so we can get rid of those that disappear */
705 	for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next)
706 		ifp->int_state &= ~(IS_CHECKED | IS_DUP);
707 
708 	/* Fetch the interface list, without too many system calls
709 	 * since we do it repeatedly.
710 	 */
711 	mib[0] = CTL_NET;
712 	mib[1] = PF_ROUTE;
713 	mib[2] = 0;
714 	mib[3] = AF_INET;
715 	mib[4] = NET_RT_IFLIST;
716 	mib[5] = 0;
717 	for (;;) {
718 		if ((needed = sysctl_buf_size) != 0) {
719 			if (sysctl(mib, 6, sysctl_buf,&needed, 0, 0) >= 0)
720 				break;
721 			/* retry if the table grew */
722 			if (errno != ENOMEM && errno != EFAULT)
723 				BADERR(1, "ifinit: sysctl(RT_IFLIST)");
724 			free(sysctl_buf);
725 			needed = 0;
726 		}
727 		if (sysctl(mib, 6, 0, &needed, 0, 0) < 0)
728 			BADERR(1,"ifinit: sysctl(RT_IFLIST) estimate");
729 		sysctl_buf = rtmalloc(sysctl_buf_size = needed,
730 				      "ifinit sysctl");
731 	}
732 
733 	ifam_lim = (struct ifa_msghdr *)(sysctl_buf + needed);
734 	for (ifam = (struct ifa_msghdr *)sysctl_buf;
735 	     ifam < ifam_lim;
736 	     ifam = ifam2) {
737 
738 		ifam2 = (struct ifa_msghdr*)((char*)ifam + ifam->ifam_msglen);
739 
740 		if (ifam->ifam_type == RTM_IFINFO) {
741 			struct sockaddr_dl *sdl;
742 
743 			ifm = (struct if_msghdr *)ifam;
744 			/* make prototype structure for the IP aliases
745 			 */
746 			memset(&ifs0, 0, sizeof(ifs0));
747 			ifs0.int_rip_sock = -1;
748 			ifs0.int_index = ifm->ifm_index;
749 			ifs0.int_if_flags = ifm->ifm_flags;
750 			ifs0.int_state = IS_CHECKED;
751 			ifs0.int_query_time = NEVER;
752 			ifs0.int_act_time = now.tv_sec;
753 			ifs0.int_data.ts = now.tv_sec;
754 			ifs0.int_data.ipackets = ifm->ifm_data.ifi_ipackets;
755 			ifs0.int_data.ierrors = ifm->ifm_data.ifi_ierrors;
756 			ifs0.int_data.opackets = ifm->ifm_data.ifi_opackets;
757 			ifs0.int_data.oerrors = ifm->ifm_data.ifi_oerrors;
758 #ifdef sgi
759 			ifs0.int_data.odrops = ifm->ifm_data.ifi_odrops;
760 #endif
761 			sdl = (struct sockaddr_dl *)(ifm + 1);
762 			sdl->sdl_data[sdl->sdl_nlen] = 0;
763 			strncpy(ifs0.int_name, sdl->sdl_data,
764 				MIN(sizeof(ifs0.int_name), sdl->sdl_nlen));
765 			continue;
766 		}
767 		if (ifam->ifam_type != RTM_NEWADDR) {
768 			logbad(1,"ifinit: out of sync");
769 			continue;
770 		}
771 		rt_xaddrs(&info, (struct sockaddr *)(ifam+1),
772 			  (struct sockaddr *)ifam2,
773 			  ifam->ifam_addrs);
774 
775 		/* Prepare for the next address of this interface, which
776 		 * will be an alias.
777 		 * Do not output RIP or Router-Discovery packets via aliases.
778 		 */
779 		memcpy(&ifs, &ifs0, sizeof(ifs));
780 		ifs0.int_state |= (IS_ALIAS | IS_NO_RIP_OUT | IS_NO_RDISC);
781 
782 		if (INFO_IFA(&info) == 0) {
783 			if (iff_up(ifs.int_if_flags)) {
784 				if (!(prev_complaints & COMP_NOADDR))
785 					msglog("%s has no address",
786 					       ifs.int_name);
787 				complaints |= COMP_NOADDR;
788 			}
789 			continue;
790 		}
791 		if (INFO_IFA(&info)->sa_family != AF_INET) {
792 			if (iff_up(ifs.int_if_flags)) {
793 				if (!(prev_complaints & COMP_NOT_INET))
794 					trace_act("%s: not AF_INET",
795 						  ifs.int_name);
796 				complaints |= COMP_NOT_INET;
797 			}
798 			continue;
799 		}
800 
801 		ifs.int_addr = S_ADDR(INFO_IFA(&info));
802 
803 		if (ntohl(ifs.int_addr)>>24 == 0
804 		    || ntohl(ifs.int_addr)>>24 == 0xff) {
805 			if (iff_up(ifs.int_if_flags)) {
806 				if (!(prev_complaints & COMP_BADADDR))
807 					msglog("%s has a bad address",
808 					       ifs.int_name);
809 				complaints |= COMP_BADADDR;
810 			}
811 			continue;
812 		}
813 
814 		if (ifs.int_if_flags & IFF_LOOPBACK) {
815 			ifs.int_state |= IS_PASSIVE | IS_NO_RIP | IS_NO_RDISC;
816 			ifs.int_dstaddr = ifs.int_addr;
817 			ifs.int_mask = HOST_MASK;
818 			ifs.int_ripv1_mask = HOST_MASK;
819 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
820 			ifs.int_net = ntohl(ifs.int_dstaddr);
821 			if (!foundloopback) {
822 				foundloopback = 1;
823 				loopaddr = ifs.int_addr;
824 				loop_rts.rts_gate = loopaddr;
825 				loop_rts.rts_router = loopaddr;
826 			}
827 
828 		} else if (ifs.int_if_flags & IFF_POINTOPOINT) {
829 			if (INFO_BRD(&info) == 0
830 			    || INFO_BRD(&info)->sa_family != AF_INET) {
831 				if (iff_up(ifs.int_if_flags)) {
832 					if (!(prev_complaints & COMP_NODST))
833 						msglog("%s has a bad"
834 						       " destination address",
835 						       ifs.int_name);
836 					complaints |= COMP_NODST;
837 				}
838 				continue;
839 			}
840 			ifs.int_dstaddr = S_ADDR(INFO_BRD(&info));
841 			if (ntohl(ifs.int_dstaddr)>>24 == 0
842 			    || ntohl(ifs.int_dstaddr)>>24 == 0xff) {
843 				if (iff_up(ifs.int_if_flags)) {
844 					if (!(prev_complaints & COMP_NODST))
845 						msglog("%s has a bad"
846 						       " destination address",
847 						       ifs.int_name);
848 					complaints |= COMP_NODST;
849 				}
850 				continue;
851 			}
852 			ifs.int_mask = HOST_MASK;
853 			ifs.int_ripv1_mask = ntohl(S_ADDR(INFO_MASK(&info)));
854 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
855 			ifs.int_net = ntohl(ifs.int_dstaddr);
856 
857 		}  else {
858 			if (INFO_MASK(&info) == 0) {
859 				if (iff_up(ifs.int_if_flags)) {
860 					if (!(prev_complaints & COMP_NOMASK))
861 						msglog("%s has no netmask",
862 						       ifs.int_name);
863 					complaints |= COMP_NOMASK;
864 				}
865 				continue;
866 			}
867 			ifs.int_dstaddr = ifs.int_addr;
868 			ifs.int_mask = ntohl(S_ADDR(INFO_MASK(&info)));
869 			ifs.int_ripv1_mask = ifs.int_mask;
870 			ifs.int_std_mask = std_mask(ifs.int_addr);
871 			ifs.int_net = ntohl(ifs.int_addr) & ifs.int_mask;
872 			if (ifs.int_mask != ifs.int_std_mask)
873 				ifs.int_state |= IS_SUBNET;
874 
875 			if (ifs.int_if_flags & IFF_BROADCAST) {
876 				if (INFO_BRD(&info) == 0) {
877 					if (iff_up(ifs.int_if_flags)) {
878 					    if (!(prev_complaints
879 						  & COMP_NOBADR))
880 						msglog("%s has"
881 						       "no broadcast address",
882 						       ifs.int_name);
883 					    complaints |= COMP_NOBADR;
884 					}
885 					continue;
886 				}
887 				ifs.int_brdaddr = S_ADDR(INFO_BRD(&info));
888 			}
889 		}
890 		ifs.int_std_net = ifs.int_net & ifs.int_std_mask;
891 		ifs.int_std_addr = htonl(ifs.int_std_net);
892 
893 		/* Use a minimum metric of one.  Treat the interface metric
894 		 * (default 0) as an increment to the hop count of one.
895 		 *
896 		 * The metric obtained from the routing socket dump of
897 		 * interface addresses is wrong.  It is not set by the
898 		 * SIOCSIFMETRIC ioctl.
899 		 */
900 #ifdef SIOCGIFMETRIC
901 		strncpy(ifr.ifr_name, ifs.int_name, sizeof(ifr.ifr_name));
902 		if (ioctl(rt_sock, SIOCGIFMETRIC, &ifr) < 0) {
903 			DBGERR(1, "ioctl(SIOCGIFMETRIC)");
904 			ifs.int_metric = 0;
905 		} else {
906 			ifs.int_metric = ifr.ifr_metric;
907 		}
908 #else
909 		ifs.int_metric = ifam->ifam_metric;
910 #endif
911 		if (ifs.int_metric > HOPCNT_INFINITY) {
912 			ifs.int_metric = 0;
913 			if (!(prev_complaints & COMP_BAD_METRIC)
914 			    && iff_up(ifs.int_if_flags)) {
915 				complaints |= COMP_BAD_METRIC;
916 				msglog("%s has a metric of %d",
917 				       ifs.int_name, ifs.int_metric);
918 			}
919 		}
920 
921 		/* See if this is a familiar interface.
922 		 * If so, stop worrying about it if it is the same.
923 		 * Start it over if it now is to somewhere else, as happens
924 		 * frequently with PPP and SLIP.
925 		 */
926 		ifp = ifwithname(ifs.int_name, ((ifs.int_state & IS_ALIAS)
927 						? ifs.int_addr
928 						: 0));
929 		if (ifp != 0) {
930 			ifp->int_state |= IS_CHECKED;
931 
932 			if (0 != ((ifp->int_if_flags ^ ifs.int_if_flags)
933 				  & (IFF_BROADCAST
934 				     | IFF_LOOPBACK
935 				     | IFF_POINTOPOINT
936 				     | IFF_MULTICAST))
937 			    || 0 != ((ifp->int_state ^ ifs.int_state)
938 				     & IS_ALIAS)
939 			    || ifp->int_addr != ifs.int_addr
940 			    || ifp->int_brdaddr != ifs.int_brdaddr
941 			    || ifp->int_dstaddr != ifs.int_dstaddr
942 			    || ifp->int_mask != ifs.int_mask
943 			    || ifp->int_metric != ifs.int_metric) {
944 				/* Forget old information about
945 				 * a changed interface.
946 				 */
947 				trace_act("interface %s has changed",
948 					  ifp->int_name);
949 				ifdel(ifp);
950 				ifp = 0;
951 			}
952 		}
953 
954 		if (ifp != 0) {
955 			/* The primary representative of an alias worries
956 			 * about how things are working.
957 			 */
958 			if (ifp->int_state & IS_ALIAS)
959 				continue;
960 
961 			/* note interfaces that have been turned off
962 			 */
963 			if (!iff_up(ifs.int_if_flags)) {
964 				if (iff_up(ifp->int_if_flags)) {
965 					msglog("interface %s to %s turned off",
966 					       ifp->int_name,
967 					       naddr_ntoa(ifp->int_dstaddr));
968 					if_bad(ifp);
969 					ifp->int_if_flags &= ~IFF_UP;
970 				} else if (now.tv_sec>(ifp->int_data.ts
971 						       + CHECK_BAD_INTERVAL)) {
972 					trace_act("interface %s has been off"
973 						  " %ld seconds; forget it",
974 						  ifp->int_name,
975 						  now.tv_sec-ifp->int_data.ts);
976 					ifdel(ifp);
977 				}
978 				continue;
979 			}
980 			/* or that were off and are now ok */
981 			if (!iff_up(ifp->int_if_flags)) {
982 				ifp->int_if_flags |= IFF_UP;
983 				(void)if_ok(ifp, "");
984 			}
985 
986 			/* If it has been long enough,
987 			 * see if the interface is broken.
988 			 */
989 			if (now.tv_sec < ifp->int_data.ts+CHECK_BAD_INTERVAL)
990 				continue;
991 
992 			in = ifs.int_data.ipackets - ifp->int_data.ipackets;
993 			ierr = ifs.int_data.ierrors - ifp->int_data.ierrors;
994 			out = ifs.int_data.opackets - ifp->int_data.opackets;
995 			oerr = ifs.int_data.oerrors - ifp->int_data.oerrors;
996 #ifdef sgi
997 			/* Through at least IRIX 6.2, PPP and SLIP
998 			 * count packets dropped by the filters.
999 			 * But FDDI rings stuck non-operational count
1000 			 * dropped packets as they wait for improvement.
1001 			 */
1002 			if (!(ifp->int_if_flags & IFF_POINTOPOINT))
1003 				oerr += (ifs.int_data.odrops
1004 					 - ifp->int_data.odrops);
1005 #endif
1006 			/* If the interface just awoke, restart the counters.
1007 			 */
1008 			if (ifp->int_data.ts == 0) {
1009 				ifp->int_data = ifs.int_data;
1010 				continue;
1011 			}
1012 			ifp->int_data = ifs.int_data;
1013 
1014 			/* Withhold judgment when the short error
1015 			 * counters wrap or the interface is reset.
1016 			 */
1017 			if (ierr < 0 || in < 0 || oerr < 0 || out < 0) {
1018 				LIM_SEC(ifinit_timer,
1019 					now.tv_sec+CHECK_BAD_INTERVAL);
1020 				continue;
1021 			}
1022 
1023 			/* Withhold judgement when there is no traffic
1024 			 */
1025 			if (in == 0 && out == 0 && ierr == 0 && oerr == 0)
1026 				continue;
1027 
1028 			/* It is bad if input or output is not working.
1029 			 * Require presistent problems before marking it dead.
1030 			 */
1031 			if ((in <= ierr && ierr > 0)
1032 			    || (out <= oerr && oerr > 0)) {
1033 				if (!(ifp->int_state & IS_SICK)) {
1034 					trace_act("interface %s to %s"
1035 						  " sick: in=%d ierr=%d"
1036 						  " out=%d oerr=%d",
1037 						  ifp->int_name,
1038 						  naddr_ntoa(ifp->int_dstaddr),
1039 						  in, ierr, out, oerr);
1040 					if_sick(ifp);
1041 					continue;
1042 				}
1043 				if (!(ifp->int_state & IS_BROKE)) {
1044 					msglog("interface %s to %s broken:"
1045 					       " in=%d ierr=%d out=%d oerr=%d",
1046 					       ifp->int_name,
1047 					       naddr_ntoa(ifp->int_dstaddr),
1048 					       in, ierr, out, oerr);
1049 					if_bad(ifp);
1050 				}
1051 				continue;
1052 			}
1053 
1054 			/* otherwise, it is active and healthy
1055 			 */
1056 			ifp->int_act_time = now.tv_sec;
1057 			(void)if_ok(ifp, "");
1058 			continue;
1059 		}
1060 
1061 		/* This is a new interface.
1062 		 * If it is dead, forget it.
1063 		 */
1064 		if (!iff_up(ifs.int_if_flags))
1065 			continue;
1066 
1067 		/* If it duplicates an existing interface,
1068 		 * complain about it, mark the other one
1069 		 * duplicated, and forget this one.
1070 		 */
1071 		ifp = check_dup(ifs.int_addr,ifs.int_dstaddr,ifs.int_mask,
1072 				ifs.int_if_flags);
1073 		if (ifp != 0) {
1074 			/* Ignore duplicates of itself, caused by having
1075 			 * IP aliases on the same network.
1076 			 */
1077 			if (!strcmp(ifp->int_name, ifs.int_name))
1078 				continue;
1079 
1080 			if (!(prev_complaints & COMP_DUP)) {
1081 				complaints |= COMP_DUP;
1082 				msglog("%s (%s%s%s) is duplicated by"
1083 				       " %s (%s%s%s)",
1084 				       ifs.int_name,
1085 				       addrname(ifs.int_addr,ifs.int_mask,1),
1086 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1087 					? "-->" : ""),
1088 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1089 					? naddr_ntoa(ifs.int_dstaddr) : ""),
1090 				       ifp->int_name,
1091 				       addrname(ifp->int_addr,ifp->int_mask,1),
1092 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1093 					? "-->" : ""),
1094 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1095 					? naddr_ntoa(ifp->int_dstaddr) : ""));
1096 			}
1097 			ifp->int_state |= IS_DUP;
1098 			continue;
1099 		}
1100 
1101 		if (0 == (ifs.int_if_flags & (IFF_POINTOPOINT | IFF_BROADCAST))
1102 		    && !(ifs.int_state & IS_PASSIVE)) {
1103 			trace_act("%s is neither broadcast, point-to-point,"
1104 				  " nor loopback",
1105 				  ifs.int_name);
1106 			if (!(ifs.int_state & IFF_MULTICAST))
1107 				ifs.int_state |= IS_NO_RDISC;
1108 		}
1109 
1110 
1111 		/* It is new and ok.   Add it to the list of interfaces
1112 		 */
1113 		ifp = (struct interface *)rtmalloc(sizeof(*ifp), "ifinit ifp");
1114 		memcpy(ifp, &ifs, sizeof(*ifp));
1115 		get_parms(ifp);
1116 		if_link(ifp);
1117 		trace_if("Add", ifp);
1118 
1119 		/* Notice likely bad netmask.
1120 		 */
1121 		if (!(prev_complaints & COMP_NETMASK)
1122 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
1123 		    && ifp->int_addr != RIP_DEFAULT) {
1124 			for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
1125 				if (ifp1->int_mask == ifp->int_mask)
1126 					continue;
1127 				if (ifp1->int_if_flags & IFF_POINTOPOINT)
1128 					continue;
1129 				if (ifp1->int_dstaddr == RIP_DEFAULT)
1130 					continue;
1131 				/* ignore aliases on the right network */
1132 				if (!strcmp(ifp->int_name, ifp1->int_name))
1133 					continue;
1134 				if (on_net(ifp->int_dstaddr,
1135 					   ifp1->int_net, ifp1->int_mask)
1136 				    || on_net(ifp1->int_dstaddr,
1137 					      ifp->int_net, ifp->int_mask)) {
1138 					msglog("possible netmask problem"
1139 					       " between %s:%s and %s:%s",
1140 					       ifp->int_name,
1141 					       addrname(htonl(ifp->int_net),
1142 							ifp->int_mask, 1),
1143 					       ifp1->int_name,
1144 					       addrname(htonl(ifp1->int_net),
1145 							ifp1->int_mask, 1));
1146 					complaints |= COMP_NETMASK;
1147 				}
1148 			}
1149 		}
1150 
1151 		if (!(ifp->int_state & IS_ALIAS)) {
1152 			/* Count the # of directly connected networks.
1153 			 */
1154 			if (!(ifp->int_if_flags & IFF_LOOPBACK))
1155 				tot_interfaces++;
1156 			if (!IS_RIP_OFF(ifp->int_state))
1157 				rip_interfaces++;
1158 
1159 			/* turn on router discovery and RIP If needed */
1160 			if_ok_rdisc(ifp);
1161 			rip_on(ifp);
1162 		}
1163 	}
1164 
1165 	/* If we are multi-homed and have at least two interfaces
1166 	 * listening to RIP, then output by default.
1167 	 */
1168 	if (!supplier_set && rip_interfaces > 1)
1169 		set_supplier();
1170 
1171 	/* If we are multi-homed, optionally advertise a route to
1172 	 * our main address.
1173 	 */
1174 	if (advertise_mhome
1175 	    || (tot_interfaces > 1
1176 		&& mhome
1177 		&& (ifp = ifwithaddr(myaddr, 0, 0)) != 0
1178 		&& foundloopback)) {
1179 		advertise_mhome = 1;
1180 		rt = rtget(myaddr, HOST_MASK);
1181 		if (rt != 0) {
1182 			if (rt->rt_ifp != ifp
1183 			    || rt->rt_router != loopaddr) {
1184 				rtdelete(rt);
1185 				rt = 0;
1186 			} else {
1187 				loop_rts.rts_ifp = ifp;
1188 				loop_rts.rts_metric = 0;
1189 				loop_rts.rts_time = rt->rt_time;
1190 				rtchange(rt, rt->rt_state | RS_MHOME,
1191 					 &loop_rts, 0);
1192 			}
1193 		}
1194 		if (rt == 0) {
1195 			loop_rts.rts_ifp = ifp;
1196 			loop_rts.rts_metric = 0;
1197 			rtadd(myaddr, HOST_MASK, RS_MHOME, &loop_rts);
1198 		}
1199 	}
1200 
1201 	for (ifp = ifnet; ifp != 0; ifp = ifp1) {
1202 		ifp1 = ifp->int_next;	/* because we may delete it */
1203 
1204 		/* Forget any interfaces that have disappeared.
1205 		 */
1206 		if (!(ifp->int_state & (IS_CHECKED | IS_REMOTE))) {
1207 			trace_act("interface %s has disappeared",
1208 				  ifp->int_name);
1209 			ifdel(ifp);
1210 			continue;
1211 		}
1212 
1213 		if ((ifp->int_state & IS_BROKE)
1214 		    && !(ifp->int_state & IS_PASSIVE))
1215 			LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
1216 
1217 		/* If we ever have a RIPv1 interface, assume we always will.
1218 		 * It might come back if it ever goes away.
1219 		 */
1220 		if (!(ifp->int_state & IS_NO_RIPV1_OUT) && supplier)
1221 			have_ripv1_out = 1;
1222 		if (!(ifp->int_state & IS_NO_RIPV1_IN))
1223 			have_ripv1_in = 1;
1224 	}
1225 
1226 	for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
1227 		/* Ensure there is always a network route for interfaces,
1228 		 * after any dead interfaces have been deleted, which
1229 		 * might affect routes for point-to-point links.
1230 		 */
1231 		if (!addrouteforif(ifp))
1232 			continue;
1233 
1234 		/* Add routes to the local end of point-to-point interfaces
1235 		 * using loopback.
1236 		 */
1237 		if ((ifp->int_if_flags & IFF_POINTOPOINT)
1238 		    && !(ifp->int_state & IS_REMOTE)
1239 		    && foundloopback) {
1240 			/* Delete any routes to the network address through
1241 			 * foreign routers. Remove even static routes.
1242 			 */
1243 			del_static(ifp->int_addr, HOST_MASK, 0, 0);
1244 			rt = rtget(ifp->int_addr, HOST_MASK);
1245 			if (rt != 0 && rt->rt_router != loopaddr) {
1246 				rtdelete(rt);
1247 				rt = 0;
1248 			}
1249 			if (rt != 0) {
1250 				if (!(rt->rt_state & RS_LOCAL)
1251 				    || rt->rt_metric > ifp->int_metric) {
1252 					ifp1 = ifp;
1253 				} else {
1254 					ifp1 = rt->rt_ifp;
1255 				}
1256 				loop_rts.rts_ifp = ifp1;
1257 				loop_rts.rts_metric = 0;
1258 				loop_rts.rts_time = rt->rt_time;
1259 				rtchange(rt, ((rt->rt_state & ~RS_NET_SYN)
1260 					      | (RS_IF|RS_LOCAL)),
1261 					 &loop_rts, 0);
1262 			} else {
1263 				loop_rts.rts_ifp = ifp;
1264 				loop_rts.rts_metric = 0;
1265 				rtadd(ifp->int_addr, HOST_MASK,
1266 				      (RS_IF | RS_LOCAL), &loop_rts);
1267 			}
1268 		}
1269 	}
1270 
1271 	/* add the authority routes */
1272 	for (intnetp = intnets; intnetp!=0; intnetp = intnetp->intnet_next) {
1273 		rt = rtget(intnetp->intnet_addr, intnetp->intnet_mask);
1274 		if (rt != 0
1275 		    && !(rt->rt_state & RS_NO_NET_SYN)
1276 		    && !(rt->rt_state & RS_NET_INT)) {
1277 			rtdelete(rt);
1278 			rt = 0;
1279 		}
1280 		if (rt == 0) {
1281 			loop_rts.rts_ifp = 0;
1282 			loop_rts.rts_metric = intnetp->intnet_metric-1;
1283 			rtadd(intnetp->intnet_addr, intnetp->intnet_mask,
1284 			      RS_NET_SYN | RS_NET_INT, &loop_rts);
1285 		}
1286 	}
1287 
1288 	prev_complaints = complaints;
1289 }
1290 
1291 
1292 static void
1293 check_net_syn(struct interface *ifp)
1294 {
1295 	struct rt_entry *rt;
1296 	static struct rt_spare new;
1297 
1298 
1299 	/* Turn on the need to automatically synthesize a network route
1300 	 * for this interface only if we are running RIPv1 on some other
1301 	 * interface that is on a different class-A,B,or C network.
1302 	 */
1303 	if (have_ripv1_out || have_ripv1_in) {
1304 		ifp->int_state |= IS_NEED_NET_SYN;
1305 		rt = rtget(ifp->int_std_addr, ifp->int_std_mask);
1306 		if (rt != 0
1307 		    && 0 == (rt->rt_state & RS_NO_NET_SYN)
1308 		    && (!(rt->rt_state & RS_NET_SYN)
1309 			|| rt->rt_metric > ifp->int_metric)) {
1310 			rtdelete(rt);
1311 			rt = 0;
1312 		}
1313 		if (rt == 0) {
1314 			new.rts_ifp = ifp;
1315 			new.rts_gate = ifp->int_addr;
1316 			new.rts_router = ifp->int_addr;
1317 			new.rts_metric = ifp->int_metric;
1318 			rtadd(ifp->int_std_addr, ifp->int_std_mask,
1319 			      RS_NET_SYN, &new);
1320 		}
1321 
1322 	} else {
1323 		ifp->int_state &= ~IS_NEED_NET_SYN;
1324 
1325 		rt = rtget(ifp->int_std_addr,
1326 			   ifp->int_std_mask);
1327 		if (rt != 0
1328 		    && (rt->rt_state & RS_NET_SYN)
1329 		    && rt->rt_ifp == ifp)
1330 			rtbad_sub(rt);
1331 	}
1332 }
1333 
1334 
1335 /* Add route for interface if not currently installed.
1336  * Create route to other end if a point-to-point link,
1337  * otherwise a route to this (sub)network.
1338  */
1339 int					/* 0=bad interface */
1340 addrouteforif(struct interface *ifp)
1341 {
1342 	struct rt_entry *rt;
1343 	static struct rt_spare new;
1344 	naddr dst;
1345 
1346 
1347 	/* skip sick interfaces
1348 	 */
1349 	if (ifp->int_state & IS_BROKE)
1350 		return 0;
1351 
1352 	/* If the interface on a subnet, then install a RIPv1 route to
1353 	 * the network as well (unless it is sick).
1354 	 */
1355 	if (ifp->int_state & IS_SUBNET)
1356 		check_net_syn(ifp);
1357 
1358 	dst = (0 != (ifp->int_if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK))
1359 	       ? ifp->int_dstaddr
1360 	       : htonl(ifp->int_net));
1361 
1362 	new.rts_ifp = ifp;
1363 	new.rts_router = ifp->int_addr;
1364 	new.rts_gate = ifp->int_addr;
1365 	new.rts_metric = ifp->int_metric;
1366 	new.rts_time = now.tv_sec;
1367 
1368 	/* If we are going to send packets to the gateway,
1369 	 * it must be reachable using our physical interfaces
1370 	 */
1371 	if ((ifp->int_state & IS_REMOTE)
1372 	    && !(ifp->int_state & IS_EXTERNAL)
1373 	    && !check_remote(ifp))
1374 		return 0;
1375 
1376 	/* We are finished if the correct main interface route exists.
1377 	 * The right route must be for the right interface, not synthesized
1378 	 * from a subnet, be a "gateway" or not as appropriate, and so forth.
1379 	 */
1380 	del_static(dst, ifp->int_mask, 0, 0);
1381 	rt = rtget(dst, ifp->int_mask);
1382 	if (rt != 0) {
1383 		if ((rt->rt_ifp != ifp
1384 		     || rt->rt_router != ifp->int_addr)
1385 		    && (!(ifp->int_state & IS_DUP)
1386 			|| rt->rt_ifp == 0
1387 			|| (rt->rt_ifp->int_state & IS_BROKE))) {
1388 			rtdelete(rt);
1389 			rt = 0;
1390 		} else {
1391 			rtchange(rt, ((rt->rt_state | RS_IF)
1392 				      & ~(RS_NET_SYN | RS_LOCAL)),
1393 				 &new, 0);
1394 		}
1395 	}
1396 	if (rt == 0) {
1397 		if (ifp->int_transitions++ > 0)
1398 			trace_act("re-install interface %s",
1399 				  ifp->int_name);
1400 
1401 		rtadd(dst, ifp->int_mask, RS_IF, &new);
1402 	}
1403 
1404 	return 1;
1405 }
1406