xref: /netbsd-src/sbin/routed/if.c (revision 4472dbe5e3bd91ef2540bada7a7ca7384627ff9b)
1 /*	$NetBSD: if.c,v 1.19 2000/03/02 20:57:42 christos 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 1.19 2000/03/02 20:57:42 christos 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 
247 	maybe = 0;
248 	for (;;) {
249 		for (ifp = ifnet; ifp; ifp = ifp->int_next) {
250 			if (ifp->int_if_flags & IFF_POINTOPOINT) {
251 				/* finished with a match */
252 				if (ifp->int_dstaddr == addr)
253 					return ifp;
254 
255 			} else {
256 				/* finished with an exact match */
257 				if (ifp->int_addr == addr)
258 					return ifp;
259 
260 				/* Look for the longest approximate match.
261 				 */
262 				if (on_net(addr, ifp->int_net, ifp->int_mask)
263 				    && (maybe == 0
264 					|| ifp->int_mask > maybe->int_mask))
265 					maybe = ifp;
266 			}
267 		}
268 
269 		if (maybe != 0)
270 			return maybe;
271 
272 		/* If there is no known interface, maybe there is a
273 		 * new interface.  So just once look for new interfaces.
274 		 */
275 		ifinit();
276 	}
277 }
278 
279 
280 /* Return the classical netmask for an IP address.
281  */
282 naddr					/* host byte order */
283 std_mask(naddr addr)			/* network byte order */
284 {
285 	NTOHL(addr);			/* was a host, not a network */
286 
287 	if (addr == 0)			/* default route has mask 0 */
288 		return 0;
289 	if (IN_CLASSA(addr))
290 		return IN_CLASSA_NET;
291 	if (IN_CLASSB(addr))
292 		return IN_CLASSB_NET;
293 	return IN_CLASSC_NET;
294 }
295 
296 
297 /* Find the netmask that would be inferred by RIPv1 listeners
298  *	on the given interface for a given network.
299  *	If no interface is specified, look for the best fitting	interface.
300  */
301 naddr
302 ripv1_mask_net(naddr addr,		/* in network byte order */
303 	       struct interface *ifp)	/* as seen on this interface */
304 {
305 	struct r1net *r1p;
306 	naddr mask = 0;
307 
308 	if (addr == 0)			/* default always has 0 mask */
309 		return mask;
310 
311 	if (ifp != 0 && ifp->int_ripv1_mask != HOST_MASK) {
312 		/* If the target network is that of the associated interface
313 		 * on which it arrived, then use the netmask of the interface.
314 		 */
315 		if (on_net(addr, ifp->int_net, ifp->int_std_mask))
316 			mask = ifp->int_ripv1_mask;
317 
318 	} else {
319 		/* Examine all interfaces, and if it the target seems
320 		 * to have the same network number of an interface, use the
321 		 * netmask of that interface.  If there is more than one
322 		 * such interface, prefer the interface with the longest
323 		 * match.
324 		 */
325 		for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
326 			if (on_net(addr, ifp->int_std_net, ifp->int_std_mask)
327 			    && ifp->int_ripv1_mask > mask
328 			    && ifp->int_ripv1_mask != HOST_MASK)
329 				mask = ifp->int_ripv1_mask;
330 		}
331 
332 	}
333 
334 	/* check special definitions */
335 	if (mask == 0) {
336 		for (r1p = r1nets; r1p != 0; r1p = r1p->r1net_next) {
337 			if (on_net(addr, r1p->r1net_net, r1p->r1net_match)
338 			    && r1p->r1net_mask > mask)
339 				mask = r1p->r1net_mask;
340 		}
341 
342 		/* Otherwise, make the classic A/B/C guess.
343 		 */
344 		if (mask == 0)
345 			mask = std_mask(addr);
346 	}
347 
348 	return mask;
349 }
350 
351 
352 naddr
353 ripv1_mask_host(naddr addr,		/* in network byte order */
354 		struct interface *ifp)	/* as seen on this interface */
355 {
356 	naddr mask = ripv1_mask_net(addr, ifp);
357 
358 
359 	/* If the computed netmask does not mask the address,
360 	 * then assume it is a host address
361 	 */
362 	if ((ntohl(addr) & ~mask) != 0)
363 		mask = HOST_MASK;
364 	return mask;
365 }
366 
367 
368 /* See if a IP address looks reasonable as a destination
369  */
370 int					/* 0=bad */
371 check_dst(naddr addr)
372 {
373 	NTOHL(addr);
374 
375 	if (IN_CLASSA(addr)) {
376 		if (addr == 0)
377 			return 1;	/* default */
378 
379 		addr >>= IN_CLASSA_NSHIFT;
380 		return (addr != 0 && addr != IN_LOOPBACKNET);
381 	}
382 
383 	return (IN_CLASSB(addr) || IN_CLASSC(addr));
384 }
385 
386 
387 /* See a new interface duplicates an existing interface.
388  */
389 struct interface *
390 check_dup(naddr addr,			/* IP address, so network byte order */
391 	  naddr dstaddr,		/* ditto */
392 	  naddr mask,			/* mask, so host byte order */
393 	  int if_flags)
394 {
395 	struct interface *ifp;
396 
397 	for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
398 		if (ifp->int_mask != mask)
399 			continue;
400 
401 		if (!iff_up(ifp->int_if_flags))
402 			continue;
403 
404 		/* The local address can only be shared with a point-to-point
405 		 * link.
406 		 */
407 		if (ifp->int_addr == addr
408 		    && (((if_flags|ifp->int_if_flags) & IFF_POINTOPOINT) == 0))
409 			return ifp;
410 
411 		if (on_net(ifp->int_dstaddr, ntohl(dstaddr),mask))
412 			return ifp;
413 	}
414 	return 0;
415 }
416 
417 
418 /* See that a remote gateway is reachable.
419  *	Note that the answer can change as real interfaces come and go.
420  */
421 int					/* 0=bad */
422 check_remote(struct interface *ifp)
423 {
424 	struct rt_entry *rt;
425 
426 	/* do not worry about other kinds */
427 	if (!(ifp->int_state & IS_REMOTE))
428 	    return 1;
429 
430 	rt = rtfind(ifp->int_addr);
431 	if (rt != 0
432 	    && rt->rt_ifp != 0
433 	    &&on_net(ifp->int_addr,
434 		     rt->rt_ifp->int_net, rt->rt_ifp->int_mask))
435 		return 1;
436 
437 	/* the gateway cannot be reached directly from one of our
438 	 * interfaces
439 	 */
440 	if (!(ifp->int_state & IS_BROKE)) {
441 		msglog("unreachable gateway %s in "_PATH_GATEWAYS,
442 		       naddr_ntoa(ifp->int_addr));
443 		if_bad(ifp);
444 	}
445 	return 0;
446 }
447 
448 
449 /* Delete an interface.
450  */
451 static void
452 ifdel(struct interface *ifp)
453 {
454 	struct ip_mreq m;
455 	struct interface *ifp1;
456 
457 
458 	trace_if("Del", ifp);
459 
460 	ifp->int_state |= IS_BROKE;
461 
462 	/* unlink the interface
463 	 */
464 	*ifp->int_prev = ifp->int_next;
465 	if (ifp->int_next != 0)
466 		ifp->int_next->int_prev = ifp->int_prev;
467 	*ifp->int_ahash_prev = ifp->int_ahash;
468 	if (ifp->int_ahash != 0)
469 		ifp->int_ahash->int_ahash_prev = ifp->int_ahash_prev;
470 	*ifp->int_nhash_prev = ifp->int_nhash;
471 	if (ifp->int_nhash != 0)
472 		ifp->int_nhash->int_nhash_prev = ifp->int_nhash_prev;
473 	if (ifp->int_if_flags & IFF_BROADCAST) {
474 		*ifp->int_bhash_prev = ifp->int_bhash;
475 		if (ifp->int_bhash != 0)
476 			ifp->int_bhash->int_bhash_prev = ifp->int_bhash_prev;
477 	}
478 	if (ifp->int_state & IS_REMOTE) {
479 		*ifp->int_rlink_prev = ifp->int_rlink;
480 		if (ifp->int_rlink != 0)
481 			ifp->int_rlink->int_rlink_prev = ifp->int_rlink_prev;
482 	}
483 
484 	if (!(ifp->int_state & IS_ALIAS)) {
485 		/* delete aliases when the main interface dies
486 		 */
487 		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
488 			if (ifp1 != ifp
489 			    && !strcmp(ifp->int_name, ifp1->int_name))
490 				ifdel(ifp1);
491 		}
492 
493 		if ((ifp->int_if_flags & IFF_MULTICAST)
494 #ifdef MCAST_PPP_BUG
495 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
496 #endif
497 		    && rip_sock >= 0) {
498 			m.imr_multiaddr.s_addr = htonl(INADDR_RIP_GROUP);
499 			m.imr_interface.s_addr = ((ifp->int_if_flags
500 						   & IFF_POINTOPOINT)
501 						  ? ifp->int_dstaddr
502 						  : ifp->int_addr);
503 			if (setsockopt(rip_sock,IPPROTO_IP,IP_DROP_MEMBERSHIP,
504 				       &m, sizeof(m)) < 0
505 			    && errno != EADDRNOTAVAIL
506 			    && !TRACEACTIONS)
507 				LOGERR("setsockopt(IP_DROP_MEMBERSHIP RIP)");
508 			if (rip_sock_mcast == ifp)
509 				rip_sock_mcast = 0;
510 		}
511 		if (ifp->int_rip_sock >= 0) {
512 			(void)close(ifp->int_rip_sock);
513 			ifp->int_rip_sock = -1;
514 			fix_select();
515 		}
516 
517 		tot_interfaces--;
518 		if (!IS_RIP_OFF(ifp->int_state))
519 			rip_interfaces--;
520 
521 		/* Zap all routes associated with this interface.
522 		 * Assume routes just using gateways beyond this interface
523 		 * will timeout naturally, and have probably already died.
524 		 */
525 		(void)rn_walktree(rhead, walk_bad, 0);
526 
527 		set_rdisc_mg(ifp, 0);
528 		if_bad_rdisc(ifp);
529 	}
530 
531 	free(ifp);
532 }
533 
534 
535 /* Mark an interface ill.
536  */
537 void
538 if_sick(struct interface *ifp)
539 {
540 	if (0 == (ifp->int_state & (IS_SICK | IS_BROKE))) {
541 		ifp->int_state |= IS_SICK;
542 		ifp->int_act_time = NEVER;
543 		trace_if("Chg", ifp);
544 
545 		LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
546 	}
547 }
548 
549 
550 /* Mark an interface dead.
551  */
552 void
553 if_bad(struct interface *ifp)
554 {
555 	struct interface *ifp1;
556 
557 
558 	if (ifp->int_state & IS_BROKE)
559 		return;
560 
561 	LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
562 
563 	ifp->int_state |= (IS_BROKE | IS_SICK);
564 	ifp->int_act_time = NEVER;
565 	ifp->int_query_time = NEVER;
566 	ifp->int_data.ts = now.tv_sec;
567 
568 	trace_if("Chg", ifp);
569 
570 	if (!(ifp->int_state & IS_ALIAS)) {
571 		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
572 			if (ifp1 != ifp
573 			    && !strcmp(ifp->int_name, ifp1->int_name))
574 				if_bad(ifp1);
575 		}
576 		(void)rn_walktree(rhead, walk_bad, 0);
577 		if_bad_rdisc(ifp);
578 	}
579 }
580 
581 
582 /* Mark an interface alive
583  */
584 int					/* 1=it was dead */
585 if_ok(struct interface *ifp,
586       const char *type)
587 {
588 	struct interface *ifp1;
589 
590 
591 	if (!(ifp->int_state & IS_BROKE)) {
592 		if (ifp->int_state & IS_SICK) {
593 			trace_act("%sinterface %s to %s working better",
594 				  type,
595 				  ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
596 			ifp->int_state &= ~IS_SICK;
597 		}
598 		return 0;
599 	}
600 
601 	msglog("%sinterface %s to %s restored",
602 	       type, ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
603 	ifp->int_state &= ~(IS_BROKE | IS_SICK);
604 	ifp->int_data.ts = 0;
605 
606 	if (!(ifp->int_state & IS_ALIAS)) {
607 		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
608 			if (ifp1 != ifp
609 			    && !strcmp(ifp->int_name, ifp1->int_name))
610 				if_ok(ifp1, type);
611 		}
612 		if_ok_rdisc(ifp);
613 	}
614 
615 	if (ifp->int_state & IS_REMOTE) {
616 		if (!addrouteforif(ifp))
617 			return 0;
618 	}
619 	return 1;
620 }
621 
622 
623 /* disassemble routing message
624  */
625 void
626 rt_xaddrs(struct rt_addrinfo *info,
627 	  struct sockaddr *sa,
628 	  struct sockaddr *lim,
629 	  int addrs)
630 {
631 	int i;
632 #ifdef _HAVE_SA_LEN
633 	static struct sockaddr sa_zero;
634 #endif
635 #ifdef sgi
636 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) \
637 		    : sizeof(__uint64_t))
638 #else
639 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) \
640 		    : sizeof(long))
641 #endif
642 
643 
644 	memset(info, 0, sizeof(*info));
645 	info->rti_addrs = addrs;
646 	for (i = 0; i < RTAX_MAX && sa < lim; i++) {
647 		if ((addrs & (1 << i)) == 0)
648 			continue;
649 #ifdef _HAVE_SA_LEN
650 		info->rti_info[i] = (sa->sa_len != 0) ? sa : &sa_zero;
651 		sa = (struct sockaddr *)((char*)(sa)
652 					 + ROUNDUP(sa->sa_len));
653 #else
654 		info->rti_info[i] = sa;
655 		sa = (struct sockaddr *)((char*)(sa)
656 					 + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
657 #endif
658 	}
659 }
660 
661 
662 /* Find the network interfaces which have configured themselves.
663  *	This must be done regularly, if only for extra addresses
664  *	that come and go on interfaces.
665  */
666 void
667 ifinit(void)
668 {
669 	static char *sysctl_buf;
670 	static size_t sysctl_buf_size = 0;
671 	uint complaints = 0;
672 	static u_int prev_complaints = 0;
673 #	define COMP_NOT_INET	0x001
674 #	define COMP_NOADDR	0x002
675 #	define COMP_BADADDR	0x004
676 #	define COMP_NODST	0x008
677 #	define COMP_NOBADR	0x010
678 #	define COMP_NOMASK	0x020
679 #	define COMP_DUP		0x040
680 #	define COMP_BAD_METRIC	0x080
681 #	define COMP_NETMASK	0x100
682 
683 	struct interface ifs, ifs0, *ifp, *ifp1;
684 	struct rt_entry *rt;
685 	size_t needed;
686 	int mib[6];
687 	struct if_msghdr *ifm;
688 	struct ifa_msghdr *ifam, *ifam_lim, *ifam2;
689 	int in, ierr, out, oerr;
690 	struct intnet *intnetp;
691 	struct rt_addrinfo info;
692 #ifdef SIOCGIFMETRIC
693 	struct ifreq ifr;
694 #endif
695 
696 
697 	last_ifinit = now;
698 	ifinit_timer.tv_sec = now.tv_sec + (supplier
699 					    ? CHECK_ACT_INTERVAL
700 					    : CHECK_QUIET_INTERVAL);
701 
702 	/* mark all interfaces so we can get rid of those that disappear */
703 	for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next)
704 		ifp->int_state &= ~(IS_CHECKED | IS_DUP);
705 
706 	/* Fetch the interface list, without too many system calls
707 	 * since we do it repeatedly.
708 	 */
709 	mib[0] = CTL_NET;
710 	mib[1] = PF_ROUTE;
711 	mib[2] = 0;
712 	mib[3] = AF_INET;
713 	mib[4] = NET_RT_IFLIST;
714 	mib[5] = 0;
715 	for (;;) {
716 		if ((needed = sysctl_buf_size) != 0) {
717 			if (sysctl(mib, 6, sysctl_buf,&needed, 0, 0) >= 0)
718 				break;
719 			/* retry if the table grew */
720 			if (errno != ENOMEM && errno != EFAULT)
721 				BADERR(1, "ifinit: sysctl(RT_IFLIST)");
722 			free(sysctl_buf);
723 			needed = 0;
724 		}
725 		if (sysctl(mib, 6, 0, &needed, 0, 0) < 0)
726 			BADERR(1,"ifinit: sysctl(RT_IFLIST) estimate");
727 		sysctl_buf = rtmalloc(sysctl_buf_size = needed,
728 				      "ifinit sysctl");
729 	}
730 
731 	ifam_lim = (struct ifa_msghdr *)(sysctl_buf + needed);
732 	for (ifam = (struct ifa_msghdr *)sysctl_buf;
733 	     ifam < ifam_lim;
734 	     ifam = ifam2) {
735 
736 		ifam2 = (struct ifa_msghdr*)((char*)ifam + ifam->ifam_msglen);
737 
738 #ifdef RTM_OIFINFO
739 		if (ifam->ifam_type == RTM_OIFINFO) {
740 			continue; /* just ignore compat message */
741 		}
742 #endif
743 		if (ifam->ifam_type == RTM_IFINFO) {
744 			struct sockaddr_dl *sdl;
745 
746 			ifm = (struct if_msghdr *)ifam;
747 			/* make prototype structure for the IP aliases
748 			 */
749 			memset(&ifs0, 0, sizeof(ifs0));
750 			ifs0.int_rip_sock = -1;
751 			ifs0.int_index = ifm->ifm_index;
752 			ifs0.int_if_flags = ifm->ifm_flags;
753 			ifs0.int_state = IS_CHECKED;
754 			ifs0.int_query_time = NEVER;
755 			ifs0.int_act_time = now.tv_sec;
756 			ifs0.int_data.ts = now.tv_sec;
757 			ifs0.int_data.ipackets = ifm->ifm_data.ifi_ipackets;
758 			ifs0.int_data.ierrors = ifm->ifm_data.ifi_ierrors;
759 			ifs0.int_data.opackets = ifm->ifm_data.ifi_opackets;
760 			ifs0.int_data.oerrors = ifm->ifm_data.ifi_oerrors;
761 #ifdef sgi
762 			ifs0.int_data.odrops = ifm->ifm_data.ifi_odrops;
763 #endif
764 			sdl = (struct sockaddr_dl *)(ifm + 1);
765 			sdl->sdl_data[sdl->sdl_nlen] = 0;
766 			strncpy(ifs0.int_name, sdl->sdl_data,
767 				MIN(sizeof(ifs0.int_name), sdl->sdl_nlen));
768 			continue;
769 		}
770 		if (ifam->ifam_type != RTM_NEWADDR) {
771 			logbad(1,"ifinit: out of sync");
772 			continue;
773 		}
774 		rt_xaddrs(&info, (struct sockaddr *)(ifam+1),
775 			  (struct sockaddr *)ifam2,
776 			  ifam->ifam_addrs);
777 
778 		/* Prepare for the next address of this interface, which
779 		 * will be an alias.
780 		 * Do not output RIP or Router-Discovery packets via aliases.
781 		 */
782 		memcpy(&ifs, &ifs0, sizeof(ifs));
783 		ifs0.int_state |= (IS_ALIAS | IS_NO_RIP_OUT | IS_NO_RDISC);
784 
785 		if (INFO_IFA(&info) == 0) {
786 			if (iff_up(ifs.int_if_flags)) {
787 				if (!(prev_complaints & COMP_NOADDR))
788 					msglog("%s has no address",
789 					       ifs.int_name);
790 				complaints |= COMP_NOADDR;
791 			}
792 			continue;
793 		}
794 		if (INFO_IFA(&info)->sa_family != AF_INET) {
795 			if (iff_up(ifs.int_if_flags)) {
796 				if (!(prev_complaints & COMP_NOT_INET))
797 					trace_act("%s: not AF_INET",
798 						  ifs.int_name);
799 				complaints |= COMP_NOT_INET;
800 			}
801 			continue;
802 		}
803 
804 		ifs.int_addr = S_ADDR(INFO_IFA(&info));
805 
806 		if (ntohl(ifs.int_addr)>>24 == 0
807 		    || ntohl(ifs.int_addr)>>24 == 0xff) {
808 			if (iff_up(ifs.int_if_flags)) {
809 				if (!(prev_complaints & COMP_BADADDR))
810 					msglog("%s has a bad address",
811 					       ifs.int_name);
812 				complaints |= COMP_BADADDR;
813 			}
814 			continue;
815 		}
816 
817 		if (ifs.int_if_flags & IFF_LOOPBACK) {
818 			ifs.int_state |= IS_PASSIVE | IS_NO_RIP | IS_NO_RDISC;
819 			ifs.int_dstaddr = ifs.int_addr;
820 			ifs.int_mask = HOST_MASK;
821 			ifs.int_ripv1_mask = HOST_MASK;
822 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
823 			ifs.int_net = ntohl(ifs.int_dstaddr);
824 			if (!foundloopback) {
825 				foundloopback = 1;
826 				loopaddr = ifs.int_addr;
827 				loop_rts.rts_gate = loopaddr;
828 				loop_rts.rts_router = loopaddr;
829 			}
830 
831 		} else if (ifs.int_if_flags & IFF_POINTOPOINT) {
832 			if (INFO_BRD(&info) == 0
833 			    || INFO_BRD(&info)->sa_family != AF_INET) {
834 				if (iff_up(ifs.int_if_flags)) {
835 					if (!(prev_complaints & COMP_NODST))
836 						msglog("%s has a bad"
837 						       " destination address",
838 						       ifs.int_name);
839 					complaints |= COMP_NODST;
840 				}
841 				continue;
842 			}
843 			ifs.int_dstaddr = S_ADDR(INFO_BRD(&info));
844 			if (ntohl(ifs.int_dstaddr)>>24 == 0
845 			    || ntohl(ifs.int_dstaddr)>>24 == 0xff) {
846 				if (iff_up(ifs.int_if_flags)) {
847 					if (!(prev_complaints & COMP_NODST))
848 						msglog("%s has a bad"
849 						       " destination address",
850 						       ifs.int_name);
851 					complaints |= COMP_NODST;
852 				}
853 				continue;
854 			}
855 			ifs.int_mask = HOST_MASK;
856 			ifs.int_ripv1_mask = ntohl(S_ADDR(INFO_MASK(&info)));
857 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
858 			ifs.int_net = ntohl(ifs.int_dstaddr);
859 
860 		}  else {
861 			if (INFO_MASK(&info) == 0) {
862 				if (iff_up(ifs.int_if_flags)) {
863 					if (!(prev_complaints & COMP_NOMASK))
864 						msglog("%s has no netmask",
865 						       ifs.int_name);
866 					complaints |= COMP_NOMASK;
867 				}
868 				continue;
869 			}
870 			ifs.int_dstaddr = ifs.int_addr;
871 			ifs.int_mask = ntohl(S_ADDR(INFO_MASK(&info)));
872 			ifs.int_ripv1_mask = ifs.int_mask;
873 			ifs.int_std_mask = std_mask(ifs.int_addr);
874 			ifs.int_net = ntohl(ifs.int_addr) & ifs.int_mask;
875 			if (ifs.int_mask != ifs.int_std_mask)
876 				ifs.int_state |= IS_SUBNET;
877 
878 			if (ifs.int_if_flags & IFF_BROADCAST) {
879 				if (INFO_BRD(&info) == 0) {
880 					if (iff_up(ifs.int_if_flags)) {
881 					    if (!(prev_complaints
882 						  & COMP_NOBADR))
883 						msglog("%s has"
884 						       "no broadcast address",
885 						       ifs.int_name);
886 					    complaints |= COMP_NOBADR;
887 					}
888 					continue;
889 				}
890 				ifs.int_brdaddr = S_ADDR(INFO_BRD(&info));
891 			}
892 		}
893 		ifs.int_std_net = ifs.int_net & ifs.int_std_mask;
894 		ifs.int_std_addr = htonl(ifs.int_std_net);
895 
896 		/* Use a minimum metric of one.  Treat the interface metric
897 		 * (default 0) as an increment to the hop count of one.
898 		 *
899 		 * The metric obtained from the routing socket dump of
900 		 * interface addresses is wrong.  It is not set by the
901 		 * SIOCSIFMETRIC ioctl.
902 		 */
903 #ifdef SIOCGIFMETRIC
904 		strncpy(ifr.ifr_name, ifs.int_name, sizeof(ifr.ifr_name));
905 		if (ioctl(rt_sock, SIOCGIFMETRIC, &ifr) < 0) {
906 			DBGERR(1, "ioctl(SIOCGIFMETRIC)");
907 			ifs.int_metric = 0;
908 		} else {
909 			ifs.int_metric = ifr.ifr_metric;
910 		}
911 #else
912 		ifs.int_metric = ifam->ifam_metric;
913 #endif
914 		if (ifs.int_metric > HOPCNT_INFINITY) {
915 			ifs.int_metric = 0;
916 			if (!(prev_complaints & COMP_BAD_METRIC)
917 			    && iff_up(ifs.int_if_flags)) {
918 				complaints |= COMP_BAD_METRIC;
919 				msglog("%s has a metric of %d",
920 				       ifs.int_name, ifs.int_metric);
921 			}
922 		}
923 
924 		/* See if this is a familiar interface.
925 		 * If so, stop worrying about it if it is the same.
926 		 * Start it over if it now is to somewhere else, as happens
927 		 * frequently with PPP and SLIP.
928 		 */
929 		ifp = ifwithname(ifs.int_name, ((ifs.int_state & IS_ALIAS)
930 						? ifs.int_addr
931 						: 0));
932 		if (ifp != 0) {
933 			ifp->int_state |= IS_CHECKED;
934 
935 			if (0 != ((ifp->int_if_flags ^ ifs.int_if_flags)
936 				  & (IFF_BROADCAST
937 				     | IFF_LOOPBACK
938 				     | IFF_POINTOPOINT
939 				     | IFF_MULTICAST))
940 			    || 0 != ((ifp->int_state ^ ifs.int_state)
941 				     & IS_ALIAS)
942 			    || ifp->int_addr != ifs.int_addr
943 			    || ifp->int_brdaddr != ifs.int_brdaddr
944 			    || ifp->int_dstaddr != ifs.int_dstaddr
945 			    || ifp->int_mask != ifs.int_mask
946 			    || ifp->int_metric != ifs.int_metric) {
947 				/* Forget old information about
948 				 * a changed interface.
949 				 */
950 				trace_act("interface %s has changed",
951 					  ifp->int_name);
952 				ifdel(ifp);
953 				ifp = 0;
954 			}
955 		}
956 
957 		if (ifp != 0) {
958 			/* The primary representative of an alias worries
959 			 * about how things are working.
960 			 */
961 			if (ifp->int_state & IS_ALIAS)
962 				continue;
963 
964 			/* note interfaces that have been turned off
965 			 */
966 			if (!iff_up(ifs.int_if_flags)) {
967 				if (iff_up(ifp->int_if_flags)) {
968 					msglog("interface %s to %s turned off",
969 					       ifp->int_name,
970 					       naddr_ntoa(ifp->int_dstaddr));
971 					if_bad(ifp);
972 					ifp->int_if_flags &= ~IFF_UP;
973 				} else if (now.tv_sec>(ifp->int_data.ts
974 						       + CHECK_BAD_INTERVAL)) {
975 					trace_act("interface %s has been off"
976 						  " %ld seconds; forget it",
977 						  ifp->int_name,
978 						  now.tv_sec-ifp->int_data.ts);
979 					ifdel(ifp);
980 				}
981 				continue;
982 			}
983 			/* or that were off and are now ok */
984 			if (!iff_up(ifp->int_if_flags)) {
985 				ifp->int_if_flags |= IFF_UP;
986 				(void)if_ok(ifp, "");
987 			}
988 
989 			/* If it has been long enough,
990 			 * see if the interface is broken.
991 			 */
992 			if (now.tv_sec < ifp->int_data.ts+CHECK_BAD_INTERVAL)
993 				continue;
994 
995 			in = ifs.int_data.ipackets - ifp->int_data.ipackets;
996 			ierr = ifs.int_data.ierrors - ifp->int_data.ierrors;
997 			out = ifs.int_data.opackets - ifp->int_data.opackets;
998 			oerr = ifs.int_data.oerrors - ifp->int_data.oerrors;
999 #ifdef sgi
1000 			/* Through at least IRIX 6.2, PPP and SLIP
1001 			 * count packets dropped by the filters.
1002 			 * But FDDI rings stuck non-operational count
1003 			 * dropped packets as they wait for improvement.
1004 			 */
1005 			if (!(ifp->int_if_flags & IFF_POINTOPOINT))
1006 				oerr += (ifs.int_data.odrops
1007 					 - ifp->int_data.odrops);
1008 #endif
1009 			/* If the interface just awoke, restart the counters.
1010 			 */
1011 			if (ifp->int_data.ts == 0) {
1012 				ifp->int_data = ifs.int_data;
1013 				continue;
1014 			}
1015 			ifp->int_data = ifs.int_data;
1016 
1017 			/* Withhold judgment when the short error
1018 			 * counters wrap or the interface is reset.
1019 			 */
1020 			if (ierr < 0 || in < 0 || oerr < 0 || out < 0) {
1021 				LIM_SEC(ifinit_timer,
1022 					now.tv_sec+CHECK_BAD_INTERVAL);
1023 				continue;
1024 			}
1025 
1026 			/* Withhold judgement when there is no traffic
1027 			 */
1028 			if (in == 0 && out == 0 && ierr == 0 && oerr == 0)
1029 				continue;
1030 
1031 			/* It is bad if input or output is not working.
1032 			 * Require presistent problems before marking it dead.
1033 			 */
1034 			if ((in <= ierr && ierr > 0)
1035 			    || (out <= oerr && oerr > 0)) {
1036 				if (!(ifp->int_state & IS_SICK)) {
1037 					trace_act("interface %s to %s"
1038 						  " sick: in=%d ierr=%d"
1039 						  " out=%d oerr=%d",
1040 						  ifp->int_name,
1041 						  naddr_ntoa(ifp->int_dstaddr),
1042 						  in, ierr, out, oerr);
1043 					if_sick(ifp);
1044 					continue;
1045 				}
1046 				if (!(ifp->int_state & IS_BROKE)) {
1047 					msglog("interface %s to %s broken:"
1048 					       " in=%d ierr=%d out=%d oerr=%d",
1049 					       ifp->int_name,
1050 					       naddr_ntoa(ifp->int_dstaddr),
1051 					       in, ierr, out, oerr);
1052 					if_bad(ifp);
1053 				}
1054 				continue;
1055 			}
1056 
1057 			/* otherwise, it is active and healthy
1058 			 */
1059 			ifp->int_act_time = now.tv_sec;
1060 			(void)if_ok(ifp, "");
1061 			continue;
1062 		}
1063 
1064 		/* This is a new interface.
1065 		 * If it is dead, forget it.
1066 		 */
1067 		if (!iff_up(ifs.int_if_flags))
1068 			continue;
1069 
1070 		/* If it duplicates an existing interface,
1071 		 * complain about it, mark the other one
1072 		 * duplicated, and forget this one.
1073 		 */
1074 		ifp = check_dup(ifs.int_addr,ifs.int_dstaddr,ifs.int_mask,
1075 				ifs.int_if_flags);
1076 		if (ifp != 0) {
1077 			/* Ignore duplicates of itself, caused by having
1078 			 * IP aliases on the same network.
1079 			 */
1080 			if (!strcmp(ifp->int_name, ifs.int_name))
1081 				continue;
1082 
1083 			if (!(prev_complaints & COMP_DUP)) {
1084 				complaints |= COMP_DUP;
1085 				msglog("%s (%s%s%s) is duplicated by"
1086 				       " %s (%s%s%s)",
1087 				       ifs.int_name,
1088 				       addrname(ifs.int_addr,ifs.int_mask,1),
1089 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1090 					? "-->" : ""),
1091 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1092 					? naddr_ntoa(ifs.int_dstaddr) : ""),
1093 				       ifp->int_name,
1094 				       addrname(ifp->int_addr,ifp->int_mask,1),
1095 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1096 					? "-->" : ""),
1097 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1098 					? naddr_ntoa(ifp->int_dstaddr) : ""));
1099 			}
1100 			ifp->int_state |= IS_DUP;
1101 			continue;
1102 		}
1103 
1104 		if (0 == (ifs.int_if_flags & (IFF_POINTOPOINT | IFF_BROADCAST))
1105 		    && !(ifs.int_state & IS_PASSIVE)) {
1106 			trace_act("%s is neither broadcast, point-to-point,"
1107 				  " nor loopback",
1108 				  ifs.int_name);
1109 			if (!(ifs.int_state & IFF_MULTICAST))
1110 				ifs.int_state |= IS_NO_RDISC;
1111 		}
1112 
1113 
1114 		/* It is new and ok.   Add it to the list of interfaces
1115 		 */
1116 		ifp = (struct interface *)rtmalloc(sizeof(*ifp), "ifinit ifp");
1117 		memcpy(ifp, &ifs, sizeof(*ifp));
1118 		get_parms(ifp);
1119 		if_link(ifp);
1120 		trace_if("Add", ifp);
1121 
1122 		/* Notice likely bad netmask.
1123 		 */
1124 		if (!(prev_complaints & COMP_NETMASK)
1125 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
1126 		    && ifp->int_addr != RIP_DEFAULT) {
1127 			for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
1128 				if (ifp1->int_mask == ifp->int_mask)
1129 					continue;
1130 				if (ifp1->int_if_flags & IFF_POINTOPOINT)
1131 					continue;
1132 				if (ifp1->int_dstaddr == RIP_DEFAULT)
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