xref: /freebsd/sbin/routed/if.c (revision 52267f7411adcc76ede961420e08c0e42f42d415)
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  * 4. 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  * $FreeBSD$
30  */
31 
32 #include "defs.h"
33 #include "pathnames.h"
34 
35 #ifdef __NetBSD__
36 __RCSID("$NetBSD$");
37 #elif defined(__FreeBSD__)
38 __RCSID("$FreeBSD$");
39 #else
40 __RCSID("$Revision: 2.27 $");
41 #ident "$Revision: 2.27 $"
42 #endif
43 
44 struct interface *ifnet;		/* all interfaces */
45 
46 /* hash table for all interfaces, big enough to tolerate ridiculous
47  * numbers of IP aliases.  Crazy numbers of aliases such as 7000
48  * still will not do well, but not just in looking up interfaces
49  * by name or address.
50  */
51 #define AHASH_LEN 211			/* must be prime */
52 #define AHASH(a) &ahash_tbl[(a)%AHASH_LEN]
53 struct interface *ahash_tbl[AHASH_LEN];
54 
55 #define BHASH_LEN 211			/* must be prime */
56 #define BHASH(a) &bhash_tbl[(a)%BHASH_LEN]
57 struct interface *bhash_tbl[BHASH_LEN];
58 
59 struct interface *remote_if;		/* remote interfaces */
60 
61 /* hash for physical interface names.
62  * Assume there are never more 100 or 200 real interfaces, and that
63  * aliases are put on the end of the hash chains.
64  */
65 #define NHASH_LEN 97
66 struct interface *nhash_tbl[NHASH_LEN];
67 
68 int	tot_interfaces;			/* # of remote and local interfaces */
69 int	rip_interfaces;			/* # of interfaces doing RIP */
70 int	foundloopback;			/* valid flag for loopaddr */
71 naddr	loopaddr;			/* our address on loopback */
72 struct	rt_spare loop_rts;
73 
74 struct timeval ifinit_timer;
75 static struct timeval last_ifinit;
76 #define IF_RESCAN_DELAY() (last_ifinit.tv_sec == now.tv_sec		\
77 			   && last_ifinit.tv_usec == now.tv_usec	\
78 			   && timercmp(&ifinit_timer, &now, >))
79 
80 int	have_ripv1_out;			/* have a RIPv1 interface */
81 int	have_ripv1_in;
82 
83 
84 static struct interface**
85 nhash(char *p)
86 {
87 	u_int i;
88 
89 	for (i = 0; *p != '\0'; p++) {
90 		i = ((i<<1) & 0x7fffffff) | ((i>>31) & 1);
91 		i ^= *p;
92 	}
93 	return &nhash_tbl[i % NHASH_LEN];
94 }
95 
96 
97 /* Link a new interface into the lists and hash tables.
98  */
99 void
100 if_link(struct interface *ifp)
101 {
102 	struct interface **hifp;
103 
104 	ifp->int_prev = &ifnet;
105 	ifp->int_next = ifnet;
106 	if (ifnet != 0)
107 		ifnet->int_prev = &ifp->int_next;
108 	ifnet = ifp;
109 
110 	hifp = AHASH(ifp->int_addr);
111 	ifp->int_ahash_prev = hifp;
112 	if ((ifp->int_ahash = *hifp) != 0)
113 		(*hifp)->int_ahash_prev = &ifp->int_ahash;
114 	*hifp = ifp;
115 
116 	if (ifp->int_if_flags & IFF_BROADCAST) {
117 		hifp = BHASH(ifp->int_brdaddr);
118 		ifp->int_bhash_prev = hifp;
119 		if ((ifp->int_bhash = *hifp) != 0)
120 			(*hifp)->int_bhash_prev = &ifp->int_bhash;
121 		*hifp = ifp;
122 	}
123 
124 	if (ifp->int_state & IS_REMOTE) {
125 		ifp->int_rlink_prev = &remote_if;
126 		ifp->int_rlink = remote_if;
127 		if (remote_if != 0)
128 			remote_if->int_rlink_prev = &ifp->int_rlink;
129 		remote_if = ifp;
130 	}
131 
132 	hifp = nhash(ifp->int_name);
133 	if (ifp->int_state & IS_ALIAS) {
134 		/* put aliases on the end of the hash chain */
135 		while (*hifp != 0)
136 			hifp = &(*hifp)->int_nhash;
137 	}
138 	ifp->int_nhash_prev = hifp;
139 	if ((ifp->int_nhash = *hifp) != 0)
140 		(*hifp)->int_nhash_prev = &ifp->int_nhash;
141 	*hifp = ifp;
142 }
143 
144 
145 /* Find the interface with an address
146  */
147 struct interface *
148 ifwithaddr(naddr addr,
149 	   int	bcast,			/* notice IFF_BROADCAST address */
150 	   int	remote)			/* include IS_REMOTE interfaces */
151 {
152 	struct interface *ifp, *possible = 0;
153 
154 	remote = (remote == 0) ? IS_REMOTE : 0;
155 
156 	for (ifp = *AHASH(addr); ifp; ifp = ifp->int_ahash) {
157 		if (ifp->int_addr != addr)
158 			continue;
159 		if ((ifp->int_state & remote) != 0)
160 			continue;
161 		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
162 			return ifp;
163 		possible = ifp;
164 	}
165 
166 	if (possible || !bcast)
167 		return possible;
168 
169 	for (ifp = *BHASH(addr); ifp; ifp = ifp->int_bhash) {
170 		if (ifp->int_brdaddr != addr)
171 			continue;
172 		if ((ifp->int_state & remote) != 0)
173 			continue;
174 		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
175 			return ifp;
176 		possible = ifp;
177 	}
178 
179 	return possible;
180 }
181 
182 
183 /* find the interface with a name
184  */
185 struct interface *
186 ifwithname(char *name,			/* "ec0" or whatever */
187 	   naddr addr)			/* 0 or network address */
188 {
189 	struct interface *ifp;
190 
191 	for (;;) {
192 		for (ifp = *nhash(name); ifp != 0; ifp = ifp->int_nhash) {
193 			/* If the network address is not specified,
194 			 * ignore any alias interfaces.  Otherwise, look
195 			 * for the interface with the target name and address.
196 			 */
197 			if (!strcmp(ifp->int_name, name)
198 			    && ((addr == 0 && !(ifp->int_state & IS_ALIAS))
199 				|| (ifp->int_addr == addr)))
200 				return ifp;
201 		}
202 
203 		/* If there is no known interface, maybe there is a
204 		 * new interface.  So just once look for new interfaces.
205 		 */
206 		if (IF_RESCAN_DELAY())
207 			return 0;
208 		ifinit();
209 	}
210 }
211 
212 
213 struct interface *
214 ifwithindex(u_short ifindex,
215 	    int rescan_ok)
216 {
217 	struct interface *ifp;
218 
219 	for (;;) {
220 		for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
221 			if (ifp->int_index == ifindex)
222 				return ifp;
223 		}
224 
225 		/* If there is no known interface, maybe there is a
226 		 * new interface.  So just once look for new interfaces.
227 		 */
228 		if (!rescan_ok
229 		    || IF_RESCAN_DELAY())
230 			return 0;
231 		ifinit();
232 	}
233 }
234 
235 
236 /* Find an interface from which the specified address
237  * should have come from.  Used for figuring out which
238  * interface a packet came in on.
239  */
240 struct interface *
241 iflookup(naddr addr)
242 {
243 	struct interface *ifp, *maybe;
244 	int once = 0;
245 
246 	maybe = 0;
247 	for (;;) {
248 		for (ifp = ifnet; ifp; ifp = ifp->int_next) {
249 			if (ifp->int_if_flags & IFF_POINTOPOINT) {
250 				/* finished with a match */
251 				if (ifp->int_dstaddr == addr)
252 					return ifp;
253 
254 			} else {
255 				/* finished with an exact match */
256 				if (ifp->int_addr == addr)
257 					return ifp;
258 
259 				/* Look for the longest approximate match.
260 				 */
261 				if (on_net(addr, ifp->int_net, ifp->int_mask)
262 				    && (maybe == 0
263 					|| ifp->int_mask > maybe->int_mask))
264 					maybe = ifp;
265 			}
266 		}
267 
268 		if (maybe != 0 || once || IF_RESCAN_DELAY())
269 			return maybe;
270 		once = 1;
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 	addr = 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 an IP address looks reasonable as a destination.
369  */
370 int					/* 0=bad */
371 check_dst(naddr addr)
372 {
373 	addr = 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_state & IS_REMOTE) || !(if_flags & IS_REMOTE))
408 		    && ifp->int_addr == addr
409 		    && (((if_flags|ifp->int_if_flags) & IFF_POINTOPOINT) == 0))
410 			return ifp;
411 
412 		if (on_net(ifp->int_dstaddr, ntohl(dstaddr),mask))
413 			return ifp;
414 	}
415 	return 0;
416 }
417 
418 
419 /* See that a remote gateway is reachable.
420  *	Note that the answer can change as real interfaces come and go.
421  */
422 int					/* 0=bad */
423 check_remote(struct interface *ifp)
424 {
425 	struct rt_entry *rt;
426 
427 	/* do not worry about other kinds */
428 	if (!(ifp->int_state & IS_REMOTE))
429 	    return 1;
430 
431 	rt = rtfind(ifp->int_addr);
432 	if (rt != 0
433 	    && rt->rt_ifp != 0
434 	    &&on_net(ifp->int_addr,
435 		     rt->rt_ifp->int_net, rt->rt_ifp->int_mask))
436 		return 1;
437 
438 	/* the gateway cannot be reached directly from one of our
439 	 * interfaces
440 	 */
441 	if (!(ifp->int_state & IS_BROKE)) {
442 		msglog("unreachable gateway %s in "_PATH_GATEWAYS,
443 		       naddr_ntoa(ifp->int_addr));
444 		if_bad(ifp);
445 	}
446 	return 0;
447 }
448 
449 
450 /* Delete an interface.
451  */
452 static void
453 ifdel(struct interface *ifp)
454 {
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) && rip_sock >= 0) {
494 			struct group_req gr;
495 			struct sockaddr_in *sin;
496 
497 			memset(&gr, 0, sizeof(gr));
498 			gr.gr_interface = ifp->int_index;
499 			sin = (struct sockaddr_in *)&gr.gr_group;
500 			sin->sin_family = AF_INET;
501 #ifdef _HAVE_SIN_LEN
502 			sin->sin_len = sizeof(struct sockaddr_in);
503 #endif
504 			sin->sin_addr.s_addr = htonl(INADDR_RIP_GROUP);
505 			if (setsockopt(rip_sock, IPPROTO_IP, MCAST_LEAVE_GROUP,
506 				       &gr, sizeof(gr)) < 0
507 			    && errno != EADDRNOTAVAIL
508 			    && !TRACEACTIONS)
509 				LOGERR("setsockopt(MCAST_LEAVE_GROUP 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 
638 	memset(info, 0, sizeof(*info));
639 	info->rti_addrs = addrs;
640 	for (i = 0; i < RTAX_MAX && sa < lim; i++) {
641 		if ((addrs & (1 << i)) == 0)
642 			continue;
643 		info->rti_info[i] = (sa->sa_len != 0) ? sa : &sa_zero;
644 		sa = (struct sockaddr *)((char*)(sa) + SA_SIZE(sa));
645 	}
646 }
647 
648 
649 /* Find the network interfaces which have configured themselves.
650  *	This must be done regularly, if only for extra addresses
651  *	that come and go on interfaces.
652  */
653 void
654 ifinit(void)
655 {
656 	static char *sysctl_buf;
657 	static size_t sysctl_buf_size = 0;
658 	uint complaints = 0;
659 	static u_int prev_complaints = 0;
660 #	define COMP_NOT_INET	0x001
661 #	define COMP_NOADDR	0x002
662 #	define COMP_BADADDR	0x004
663 #	define COMP_NODST	0x008
664 #	define COMP_NOBADR	0x010
665 #	define COMP_NOMASK	0x020
666 #	define COMP_DUP		0x040
667 #	define COMP_BAD_METRIC	0x080
668 #	define COMP_NETMASK	0x100
669 
670 	struct interface ifs, ifs0, *ifp, *ifp1;
671 	struct rt_entry *rt;
672 	size_t needed;
673 	int mib[6];
674 	struct if_msghdr *ifm;
675 	struct ifa_msghdr *ifam, *ifam_lim, *ifam2;
676 	int in, ierr, out, oerr;
677 	struct intnet *intnetp;
678 	struct rt_addrinfo info;
679 #ifdef SIOCGIFMETRIC
680 	struct ifreq ifr;
681 #endif
682 
683 
684 	last_ifinit = now;
685 	ifinit_timer.tv_sec = now.tv_sec + (supplier
686 					    ? CHECK_ACT_INTERVAL
687 					    : CHECK_QUIET_INTERVAL);
688 
689 	/* mark all interfaces so we can get rid of those that disappear */
690 	for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next)
691 		ifp->int_state &= ~(IS_CHECKED | IS_DUP);
692 
693 	/* Fetch the interface list, without too many system calls
694 	 * since we do it repeatedly.
695 	 */
696 	mib[0] = CTL_NET;
697 	mib[1] = PF_ROUTE;
698 	mib[2] = 0;
699 	mib[3] = AF_INET;
700 	mib[4] = NET_RT_IFLIST;
701 	mib[5] = 0;
702 	for (;;) {
703 		if ((needed = sysctl_buf_size) != 0) {
704 			if (sysctl(mib, 6, sysctl_buf,&needed, 0, 0) >= 0)
705 				break;
706 			/* retry if the table grew */
707 			if (errno != ENOMEM && errno != EFAULT)
708 				BADERR(1, "ifinit: sysctl(RT_IFLIST)");
709 			free(sysctl_buf);
710 			needed = 0;
711 		}
712 		if (sysctl(mib, 6, 0, &needed, 0, 0) < 0)
713 			BADERR(1,"ifinit: sysctl(RT_IFLIST) estimate");
714 		sysctl_buf = rtmalloc(sysctl_buf_size = needed,
715 				      "ifinit sysctl");
716 	}
717 
718 	ifam_lim = (struct ifa_msghdr *)(sysctl_buf + needed);
719 	for (ifam = (struct ifa_msghdr *)sysctl_buf;
720 	     ifam < ifam_lim;
721 	     ifam = ifam2) {
722 
723 		ifam2 = (struct ifa_msghdr*)((char*)ifam + ifam->ifam_msglen);
724 
725 #ifdef RTM_OIFINFO
726 		if (ifam->ifam_type == RTM_OIFINFO)
727 			continue;	/* just ignore compat message */
728 #endif
729 		if (ifam->ifam_type == RTM_IFINFO) {
730 			struct sockaddr_dl *sdl;
731 
732 			ifm = (struct if_msghdr *)ifam;
733 			/* make prototype structure for the IP aliases
734 			 */
735 			memset(&ifs0, 0, sizeof(ifs0));
736 			ifs0.int_rip_sock = -1;
737 			ifs0.int_index = ifm->ifm_index;
738 			ifs0.int_if_flags = ifm->ifm_flags;
739 			ifs0.int_state = IS_CHECKED;
740 			ifs0.int_query_time = NEVER;
741 			ifs0.int_act_time = now.tv_sec;
742 			ifs0.int_data.ts = now.tv_sec;
743 			ifs0.int_data.ipackets = ifm->ifm_data.ifi_ipackets;
744 			ifs0.int_data.ierrors = ifm->ifm_data.ifi_ierrors;
745 			ifs0.int_data.opackets = ifm->ifm_data.ifi_opackets;
746 			ifs0.int_data.oerrors = ifm->ifm_data.ifi_oerrors;
747 #ifdef sgi
748 			ifs0.int_data.odrops = ifm->ifm_data.ifi_odrops;
749 #endif
750 			sdl = (struct sockaddr_dl *)(ifm + 1);
751 			sdl->sdl_data[sdl->sdl_nlen] = 0;
752 			strncpy(ifs0.int_name, sdl->sdl_data,
753 				MIN(sizeof(ifs0.int_name), sdl->sdl_nlen));
754 			continue;
755 		}
756 		if (ifam->ifam_type != RTM_NEWADDR) {
757 			logbad(1,"ifinit: out of sync");
758 			continue;
759 		}
760 		rt_xaddrs(&info, (struct sockaddr *)(ifam+1),
761 			  (struct sockaddr *)ifam2,
762 			  ifam->ifam_addrs);
763 
764 		/* Prepare for the next address of this interface, which
765 		 * will be an alias.
766 		 * Do not output RIP or Router-Discovery packets via aliases.
767 		 */
768 		memcpy(&ifs, &ifs0, sizeof(ifs));
769 		ifs0.int_state |= (IS_ALIAS | IS_NO_RIP_OUT | IS_NO_RDISC);
770 
771 		if (INFO_IFA(&info) == 0) {
772 			if (iff_up(ifs.int_if_flags)) {
773 				if (!(prev_complaints & COMP_NOADDR))
774 					msglog("%s has no address",
775 					       ifs.int_name);
776 				complaints |= COMP_NOADDR;
777 			}
778 			continue;
779 		}
780 		if (INFO_IFA(&info)->sa_family != AF_INET) {
781 			if (iff_up(ifs.int_if_flags)) {
782 				if (!(prev_complaints & COMP_NOT_INET))
783 					trace_act("%s: not AF_INET",
784 						  ifs.int_name);
785 				complaints |= COMP_NOT_INET;
786 			}
787 			continue;
788 		}
789 
790 		ifs.int_addr = S_ADDR(INFO_IFA(&info));
791 
792 		if (ntohl(ifs.int_addr)>>24 == 0
793 		    || ntohl(ifs.int_addr)>>24 == 0xff) {
794 			if (iff_up(ifs.int_if_flags)) {
795 				if (!(prev_complaints & COMP_BADADDR))
796 					msglog("%s has a bad address",
797 					       ifs.int_name);
798 				complaints |= COMP_BADADDR;
799 			}
800 			continue;
801 		}
802 
803 		if (ifs.int_if_flags & IFF_LOOPBACK) {
804 			ifs.int_state |= IS_NO_RIP | IS_NO_RDISC;
805 			if (ifs.int_addr == htonl(INADDR_LOOPBACK))
806 				ifs.int_state |= IS_PASSIVE;
807 			ifs.int_dstaddr = ifs.int_addr;
808 			ifs.int_mask = HOST_MASK;
809 			ifs.int_ripv1_mask = HOST_MASK;
810 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
811 			ifs.int_net = ntohl(ifs.int_dstaddr);
812 			if (!foundloopback) {
813 				foundloopback = 1;
814 				loopaddr = ifs.int_addr;
815 				loop_rts.rts_gate = loopaddr;
816 				loop_rts.rts_router = loopaddr;
817 			}
818 
819 		} else if (ifs.int_if_flags & IFF_POINTOPOINT) {
820 			if (INFO_BRD(&info) == 0
821 			    || INFO_BRD(&info)->sa_family != AF_INET) {
822 				if (iff_up(ifs.int_if_flags)) {
823 					if (!(prev_complaints & COMP_NODST))
824 						msglog("%s has a bad"
825 						       " destination address",
826 						       ifs.int_name);
827 					complaints |= COMP_NODST;
828 				}
829 				continue;
830 			}
831 			ifs.int_dstaddr = S_ADDR(INFO_BRD(&info));
832 			if (ntohl(ifs.int_dstaddr)>>24 == 0
833 			    || ntohl(ifs.int_dstaddr)>>24 == 0xff) {
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_mask = HOST_MASK;
844 			ifs.int_ripv1_mask = ntohl(S_ADDR(INFO_MASK(&info)));
845 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
846 			ifs.int_net = ntohl(ifs.int_dstaddr);
847 
848 		}  else {
849 			if (INFO_MASK(&info) == 0) {
850 				if (iff_up(ifs.int_if_flags)) {
851 					if (!(prev_complaints & COMP_NOMASK))
852 						msglog("%s has no netmask",
853 						       ifs.int_name);
854 					complaints |= COMP_NOMASK;
855 				}
856 				continue;
857 			}
858 			ifs.int_dstaddr = ifs.int_addr;
859 			ifs.int_mask = ntohl(S_ADDR(INFO_MASK(&info)));
860 			ifs.int_ripv1_mask = ifs.int_mask;
861 			ifs.int_std_mask = std_mask(ifs.int_addr);
862 			ifs.int_net = ntohl(ifs.int_addr) & ifs.int_mask;
863 			if (ifs.int_mask != ifs.int_std_mask)
864 				ifs.int_state |= IS_SUBNET;
865 
866 			if (ifs.int_if_flags & IFF_BROADCAST) {
867 				if (INFO_BRD(&info) == 0) {
868 					if (iff_up(ifs.int_if_flags)) {
869 					    if (!(prev_complaints
870 						  & COMP_NOBADR))
871 						msglog("%s has"
872 						       "no broadcast address",
873 						       ifs.int_name);
874 					    complaints |= COMP_NOBADR;
875 					}
876 					continue;
877 				}
878 				ifs.int_brdaddr = S_ADDR(INFO_BRD(&info));
879 			}
880 		}
881 		ifs.int_std_net = ifs.int_net & ifs.int_std_mask;
882 		ifs.int_std_addr = htonl(ifs.int_std_net);
883 
884 		/* Use a minimum metric of one.  Treat the interface metric
885 		 * (default 0) as an increment to the hop count of one.
886 		 *
887 		 * The metric obtained from the routing socket dump of
888 		 * interface addresses is wrong.  It is not set by the
889 		 * SIOCSIFMETRIC ioctl.
890 		 */
891 #ifdef SIOCGIFMETRIC
892 		strncpy(ifr.ifr_name, ifs.int_name, sizeof(ifr.ifr_name));
893 		if (ioctl(rt_sock, SIOCGIFMETRIC, &ifr) < 0) {
894 			DBGERR(1, "ioctl(SIOCGIFMETRIC)");
895 			ifs.int_metric = 0;
896 		} else {
897 			ifs.int_metric = ifr.ifr_metric;
898 		}
899 #else
900 		ifs.int_metric = ifam->ifam_metric;
901 #endif
902 		if (ifs.int_metric > HOPCNT_INFINITY) {
903 			ifs.int_metric = 0;
904 			if (!(prev_complaints & COMP_BAD_METRIC)
905 			    && iff_up(ifs.int_if_flags)) {
906 				complaints |= COMP_BAD_METRIC;
907 				msglog("%s has a metric of %d",
908 				       ifs.int_name, ifs.int_metric);
909 			}
910 		}
911 
912 		/* See if this is a familiar interface.
913 		 * If so, stop worrying about it if it is the same.
914 		 * Start it over if it now is to somewhere else, as happens
915 		 * frequently with PPP and SLIP.
916 		 */
917 		ifp = ifwithname(ifs.int_name, ((ifs.int_state & IS_ALIAS)
918 						? ifs.int_addr
919 						: 0));
920 		if (ifp != 0) {
921 			ifp->int_state |= IS_CHECKED;
922 
923 			if (0 != ((ifp->int_if_flags ^ ifs.int_if_flags)
924 				  & (IFF_BROADCAST
925 				     | IFF_LOOPBACK
926 				     | IFF_POINTOPOINT
927 				     | IFF_MULTICAST))
928 			    || 0 != ((ifp->int_state ^ ifs.int_state)
929 				     & IS_ALIAS)
930 			    || ifp->int_addr != ifs.int_addr
931 			    || ifp->int_brdaddr != ifs.int_brdaddr
932 			    || ifp->int_dstaddr != ifs.int_dstaddr
933 			    || ifp->int_mask != ifs.int_mask
934 			    || ifp->int_metric != ifs.int_metric) {
935 				/* Forget old information about
936 				 * a changed interface.
937 				 */
938 				trace_act("interface %s has changed",
939 					  ifp->int_name);
940 				ifdel(ifp);
941 				ifp = 0;
942 			}
943 		}
944 
945 		if (ifp != 0) {
946 			/* The primary representative of an alias worries
947 			 * about how things are working.
948 			 */
949 			if (ifp->int_state & IS_ALIAS)
950 				continue;
951 
952 			/* note interfaces that have been turned off
953 			 */
954 			if (!iff_up(ifs.int_if_flags)) {
955 				if (iff_up(ifp->int_if_flags)) {
956 					msglog("interface %s to %s turned off",
957 					       ifp->int_name,
958 					       naddr_ntoa(ifp->int_dstaddr));
959 					if_bad(ifp);
960 					ifp->int_if_flags &= ~IFF_UP;
961 				} else if (now.tv_sec>(ifp->int_data.ts
962 						       + CHECK_BAD_INTERVAL)) {
963 					trace_act("interface %s has been off"
964 						  " %ld seconds; forget it",
965 						  ifp->int_name,
966 						  now.tv_sec-ifp->int_data.ts);
967 					ifdel(ifp);
968 				}
969 				continue;
970 			}
971 			/* or that were off and are now ok */
972 			if (!iff_up(ifp->int_if_flags)) {
973 				ifp->int_if_flags |= IFF_UP;
974 				(void)if_ok(ifp, "");
975 			}
976 
977 			/* If it has been long enough,
978 			 * see if the interface is broken.
979 			 */
980 			if (now.tv_sec < ifp->int_data.ts+CHECK_BAD_INTERVAL)
981 				continue;
982 
983 			in = ifs.int_data.ipackets - ifp->int_data.ipackets;
984 			ierr = ifs.int_data.ierrors - ifp->int_data.ierrors;
985 			out = ifs.int_data.opackets - ifp->int_data.opackets;
986 			oerr = ifs.int_data.oerrors - ifp->int_data.oerrors;
987 #ifdef sgi
988 			/* Through at least IRIX 6.2, PPP and SLIP
989 			 * count packets dropped by the filters.
990 			 * But FDDI rings stuck non-operational count
991 			 * dropped packets as they wait for improvement.
992 			 */
993 			if (!(ifp->int_if_flags & IFF_POINTOPOINT))
994 				oerr += (ifs.int_data.odrops
995 					 - ifp->int_data.odrops);
996 #endif
997 			/* If the interface just awoke, restart the counters.
998 			 */
999 			if (ifp->int_data.ts == 0) {
1000 				ifp->int_data = ifs.int_data;
1001 				continue;
1002 			}
1003 			ifp->int_data = ifs.int_data;
1004 
1005 			/* Withhold judgment when the short error
1006 			 * counters wrap or the interface is reset.
1007 			 */
1008 			if (ierr < 0 || in < 0 || oerr < 0 || out < 0) {
1009 				LIM_SEC(ifinit_timer,
1010 					now.tv_sec+CHECK_BAD_INTERVAL);
1011 				continue;
1012 			}
1013 
1014 			/* Withhold judgement when there is no traffic
1015 			 */
1016 			if (in == 0 && out == 0 && ierr == 0 && oerr == 0)
1017 				continue;
1018 
1019 			/* It is bad if input or output is not working.
1020 			 * Require presistent problems before marking it dead.
1021 			 */
1022 			if ((in <= ierr && ierr > 0)
1023 			    || (out <= oerr && oerr > 0)) {
1024 				if (!(ifp->int_state & IS_SICK)) {
1025 					trace_act("interface %s to %s"
1026 						  " sick: in=%d ierr=%d"
1027 						  " out=%d oerr=%d",
1028 						  ifp->int_name,
1029 						  naddr_ntoa(ifp->int_dstaddr),
1030 						  in, ierr, out, oerr);
1031 					if_sick(ifp);
1032 					continue;
1033 				}
1034 				if (!(ifp->int_state & IS_BROKE)) {
1035 					msglog("interface %s to %s broken:"
1036 					       " in=%d ierr=%d out=%d oerr=%d",
1037 					       ifp->int_name,
1038 					       naddr_ntoa(ifp->int_dstaddr),
1039 					       in, ierr, out, oerr);
1040 					if_bad(ifp);
1041 				}
1042 				continue;
1043 			}
1044 
1045 			/* otherwise, it is active and healthy
1046 			 */
1047 			ifp->int_act_time = now.tv_sec;
1048 			(void)if_ok(ifp, "");
1049 			continue;
1050 		}
1051 
1052 		/* This is a new interface.
1053 		 * If it is dead, forget it.
1054 		 */
1055 		if (!iff_up(ifs.int_if_flags))
1056 			continue;
1057 
1058 		/* If it duplicates an existing interface,
1059 		 * complain about it, mark the other one
1060 		 * duplicated, and forget this one.
1061 		 */
1062 		ifp = check_dup(ifs.int_addr,ifs.int_dstaddr,ifs.int_mask,
1063 				ifs.int_if_flags);
1064 		if (ifp != 0) {
1065 			/* Ignore duplicates of itself, caused by having
1066 			 * IP aliases on the same network.
1067 			 */
1068 			if (!strcmp(ifp->int_name, ifs.int_name))
1069 				continue;
1070 
1071 			if (!(prev_complaints & COMP_DUP)) {
1072 				complaints |= COMP_DUP;
1073 				msglog("%s (%s%s%s) is duplicated by"
1074 				       " %s (%s%s%s)",
1075 				       ifs.int_name,
1076 				       addrname(ifs.int_addr,ifs.int_mask,1),
1077 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1078 					? "-->" : ""),
1079 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1080 					? naddr_ntoa(ifs.int_dstaddr) : ""),
1081 				       ifp->int_name,
1082 				       addrname(ifp->int_addr,ifp->int_mask,1),
1083 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1084 					? "-->" : ""),
1085 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1086 					? naddr_ntoa(ifp->int_dstaddr) : ""));
1087 			}
1088 			ifp->int_state |= IS_DUP;
1089 			continue;
1090 		}
1091 
1092 		if (0 == (ifs.int_if_flags & (IFF_POINTOPOINT | IFF_BROADCAST | IFF_LOOPBACK))) {
1093 			trace_act("%s is neither broadcast, point-to-point,"
1094 				  " nor loopback",
1095 				  ifs.int_name);
1096 			if (!(ifs.int_state & IFF_MULTICAST))
1097 				ifs.int_state |= IS_NO_RDISC;
1098 		}
1099 
1100 
1101 		/* It is new and ok.   Add it to the list of interfaces
1102 		 */
1103 		ifp = (struct interface *)rtmalloc(sizeof(*ifp), "ifinit ifp");
1104 		memcpy(ifp, &ifs, sizeof(*ifp));
1105 		get_parms(ifp);
1106 		if_link(ifp);
1107 		trace_if("Add", ifp);
1108 
1109 		/* Notice likely bad netmask.
1110 		 */
1111 		if (!(prev_complaints & COMP_NETMASK)
1112 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
1113 		    && ifp->int_addr != RIP_DEFAULT) {
1114 			for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
1115 				if (ifp1->int_mask == ifp->int_mask)
1116 					continue;
1117 				if (ifp1->int_if_flags & IFF_POINTOPOINT)
1118 					continue;
1119 				if (ifp1->int_dstaddr == RIP_DEFAULT)
1120 					continue;
1121 				/* ignore aliases on the right network */
1122 				if (!strcmp(ifp->int_name, ifp1->int_name))
1123 					continue;
1124 				if (on_net(ifp->int_dstaddr,
1125 					   ifp1->int_net, ifp1->int_mask)
1126 				    || on_net(ifp1->int_dstaddr,
1127 					      ifp->int_net, ifp->int_mask)) {
1128 					msglog("possible netmask problem"
1129 					       " between %s:%s and %s:%s",
1130 					       ifp->int_name,
1131 					       addrname(htonl(ifp->int_net),
1132 							ifp->int_mask, 1),
1133 					       ifp1->int_name,
1134 					       addrname(htonl(ifp1->int_net),
1135 							ifp1->int_mask, 1));
1136 					complaints |= COMP_NETMASK;
1137 				}
1138 			}
1139 		}
1140 
1141 		if (!(ifp->int_state & IS_ALIAS)) {
1142 			/* Count the # of directly connected networks.
1143 			 */
1144 			if (!(ifp->int_if_flags & IFF_LOOPBACK))
1145 				tot_interfaces++;
1146 			if (!IS_RIP_OFF(ifp->int_state))
1147 				rip_interfaces++;
1148 
1149 			/* turn on router discovery and RIP If needed */
1150 			if_ok_rdisc(ifp);
1151 			rip_on(ifp);
1152 		}
1153 	}
1154 
1155 	/* If we are multi-homed and have at least two interfaces
1156 	 * listening to RIP, then output by default.
1157 	 */
1158 	if (!supplier_set && rip_interfaces > 1)
1159 		set_supplier();
1160 
1161 	/* If we are multi-homed, optionally advertise a route to
1162 	 * our main address.
1163 	 */
1164 	if (advertise_mhome
1165 	    || (tot_interfaces > 1
1166 		&& mhome
1167 		&& (ifp = ifwithaddr(myaddr, 0, 0)) != 0
1168 		&& foundloopback)) {
1169 		advertise_mhome = 1;
1170 		rt = rtget(myaddr, HOST_MASK);
1171 		if (rt != 0) {
1172 			if (rt->rt_ifp != ifp
1173 			    || rt->rt_router != loopaddr) {
1174 				rtdelete(rt);
1175 				rt = 0;
1176 			} else {
1177 				loop_rts.rts_ifp = ifp;
1178 				loop_rts.rts_metric = 0;
1179 				loop_rts.rts_time = rt->rt_time;
1180 				rtchange(rt, rt->rt_state | RS_MHOME,
1181 					 &loop_rts, 0);
1182 			}
1183 		}
1184 		if (rt == 0) {
1185 			loop_rts.rts_ifp = ifp;
1186 			loop_rts.rts_metric = 0;
1187 			rtadd(myaddr, HOST_MASK, RS_MHOME, &loop_rts);
1188 		}
1189 	}
1190 
1191 	for (ifp = ifnet; ifp != 0; ifp = ifp1) {
1192 		ifp1 = ifp->int_next;	/* because we may delete it */
1193 
1194 		/* Forget any interfaces that have disappeared.
1195 		 */
1196 		if (!(ifp->int_state & (IS_CHECKED | IS_REMOTE))) {
1197 			trace_act("interface %s has disappeared",
1198 				  ifp->int_name);
1199 			ifdel(ifp);
1200 			continue;
1201 		}
1202 
1203 		if ((ifp->int_state & IS_BROKE)
1204 		    && !(ifp->int_state & IS_PASSIVE))
1205 			LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
1206 
1207 		/* If we ever have a RIPv1 interface, assume we always will.
1208 		 * It might come back if it ever goes away.
1209 		 */
1210 		if (!(ifp->int_state & IS_NO_RIPV1_OUT) && supplier)
1211 			have_ripv1_out = 1;
1212 		if (!(ifp->int_state & IS_NO_RIPV1_IN))
1213 			have_ripv1_in = 1;
1214 	}
1215 
1216 	for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
1217 		/* Ensure there is always a network route for interfaces,
1218 		 * after any dead interfaces have been deleted, which
1219 		 * might affect routes for point-to-point links.
1220 		 */
1221 		if (!addrouteforif(ifp))
1222 			continue;
1223 
1224 		/* Add routes to the local end of point-to-point interfaces
1225 		 * using loopback.
1226 		 */
1227 		if ((ifp->int_if_flags & IFF_POINTOPOINT)
1228 		    && !(ifp->int_state & IS_REMOTE)
1229 		    && foundloopback) {
1230 			/* Delete any routes to the network address through
1231 			 * foreign routers. Remove even static routes.
1232 			 */
1233 			del_static(ifp->int_addr, HOST_MASK, 0, 0);
1234 			rt = rtget(ifp->int_addr, HOST_MASK);
1235 			if (rt != 0 && rt->rt_router != loopaddr) {
1236 				rtdelete(rt);
1237 				rt = 0;
1238 			}
1239 			if (rt != 0) {
1240 				if (!(rt->rt_state & RS_LOCAL)
1241 				    || rt->rt_metric > ifp->int_metric) {
1242 					ifp1 = ifp;
1243 				} else {
1244 					ifp1 = rt->rt_ifp;
1245 				}
1246 				loop_rts.rts_ifp = ifp1;
1247 				loop_rts.rts_metric = 0;
1248 				loop_rts.rts_time = rt->rt_time;
1249 				rtchange(rt, ((rt->rt_state & ~RS_NET_SYN)
1250 					      | (RS_IF|RS_LOCAL)),
1251 					 &loop_rts, 0);
1252 			} else {
1253 				loop_rts.rts_ifp = ifp;
1254 				loop_rts.rts_metric = 0;
1255 				rtadd(ifp->int_addr, HOST_MASK,
1256 				      (RS_IF | RS_LOCAL), &loop_rts);
1257 			}
1258 		}
1259 	}
1260 
1261 	/* add the authority routes */
1262 	for (intnetp = intnets; intnetp!=0; intnetp = intnetp->intnet_next) {
1263 		rt = rtget(intnetp->intnet_addr, intnetp->intnet_mask);
1264 		if (rt != 0
1265 		    && !(rt->rt_state & RS_NO_NET_SYN)
1266 		    && !(rt->rt_state & RS_NET_INT)) {
1267 			rtdelete(rt);
1268 			rt = 0;
1269 		}
1270 		if (rt == 0) {
1271 			loop_rts.rts_ifp = 0;
1272 			loop_rts.rts_metric = intnetp->intnet_metric-1;
1273 			rtadd(intnetp->intnet_addr, intnetp->intnet_mask,
1274 			      RS_NET_SYN | RS_NET_INT, &loop_rts);
1275 		}
1276 	}
1277 
1278 	prev_complaints = complaints;
1279 }
1280 
1281 
1282 static void
1283 check_net_syn(struct interface *ifp)
1284 {
1285 	struct rt_entry *rt;
1286 	static struct rt_spare new;
1287 
1288 
1289 	/* Turn on the need to automatically synthesize a network route
1290 	 * for this interface only if we are running RIPv1 on some other
1291 	 * interface that is on a different class-A,B,or C network.
1292 	 */
1293 	if (have_ripv1_out || have_ripv1_in) {
1294 		ifp->int_state |= IS_NEED_NET_SYN;
1295 		rt = rtget(ifp->int_std_addr, ifp->int_std_mask);
1296 		if (rt != 0
1297 		    && 0 == (rt->rt_state & RS_NO_NET_SYN)
1298 		    && (!(rt->rt_state & RS_NET_SYN)
1299 			|| rt->rt_metric > ifp->int_metric)) {
1300 			rtdelete(rt);
1301 			rt = 0;
1302 		}
1303 		if (rt == 0) {
1304 			new.rts_ifp = ifp;
1305 			new.rts_gate = ifp->int_addr;
1306 			new.rts_router = ifp->int_addr;
1307 			new.rts_metric = ifp->int_metric;
1308 			rtadd(ifp->int_std_addr, ifp->int_std_mask,
1309 			      RS_NET_SYN, &new);
1310 		}
1311 
1312 	} else {
1313 		ifp->int_state &= ~IS_NEED_NET_SYN;
1314 
1315 		rt = rtget(ifp->int_std_addr,
1316 			   ifp->int_std_mask);
1317 		if (rt != 0
1318 		    && (rt->rt_state & RS_NET_SYN)
1319 		    && rt->rt_ifp == ifp)
1320 			rtbad_sub(rt);
1321 	}
1322 }
1323 
1324 
1325 /* Add route for interface if not currently installed.
1326  * Create route to other end if a point-to-point link,
1327  * otherwise a route to this (sub)network.
1328  */
1329 int					/* 0=bad interface */
1330 addrouteforif(struct interface *ifp)
1331 {
1332 	struct rt_entry *rt;
1333 	static struct rt_spare new;
1334 	naddr dst;
1335 
1336 
1337 	/* skip sick interfaces
1338 	 */
1339 	if (ifp->int_state & IS_BROKE)
1340 		return 0;
1341 
1342 	/* If the interface on a subnet, then install a RIPv1 route to
1343 	 * the network as well (unless it is sick).
1344 	 */
1345 	if (ifp->int_state & IS_SUBNET)
1346 		check_net_syn(ifp);
1347 
1348 	dst = (0 != (ifp->int_if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK))
1349 	       ? ifp->int_dstaddr
1350 	       : htonl(ifp->int_net));
1351 
1352 	new.rts_ifp = ifp;
1353 	new.rts_router = ifp->int_addr;
1354 	new.rts_gate = ifp->int_addr;
1355 	new.rts_metric = ifp->int_metric;
1356 	new.rts_time = now.tv_sec;
1357 
1358 	/* If we are going to send packets to the gateway,
1359 	 * it must be reachable using our physical interfaces
1360 	 */
1361 	if ((ifp->int_state & IS_REMOTE)
1362 	    && !(ifp->int_state & IS_EXTERNAL)
1363 	    && !check_remote(ifp))
1364 		return 0;
1365 
1366 	/* We are finished if the correct main interface route exists.
1367 	 * The right route must be for the right interface, not synthesized
1368 	 * from a subnet, be a "gateway" or not as appropriate, and so forth.
1369 	 */
1370 	del_static(dst, ifp->int_mask, 0, 0);
1371 	rt = rtget(dst, ifp->int_mask);
1372 	if (rt != 0) {
1373 		if ((rt->rt_ifp != ifp
1374 		     || rt->rt_router != ifp->int_addr)
1375 		    && (!(ifp->int_state & IS_DUP)
1376 			|| rt->rt_ifp == 0
1377 			|| (rt->rt_ifp->int_state & IS_BROKE))) {
1378 			rtdelete(rt);
1379 			rt = 0;
1380 		} else {
1381 			rtchange(rt, ((rt->rt_state | RS_IF)
1382 				      & ~(RS_NET_SYN | RS_LOCAL)),
1383 				 &new, 0);
1384 		}
1385 	}
1386 	if (rt == 0) {
1387 		if (ifp->int_transitions++ > 0)
1388 			trace_act("re-install interface %s",
1389 				  ifp->int_name);
1390 
1391 		rtadd(dst, ifp->int_mask, RS_IF, &new);
1392 	}
1393 
1394 	return 1;
1395 }
1396