xref: /dragonfly/sbin/routed/if.c (revision 75a74ed8)
1 /*
2  * Copyright (c) 1983, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * @(#)if.c	8.1 (Berkeley) 6/5/93
30  * $FreeBSD: src/sbin/routed/if.c,v 1.6.2.1 2000/08/14 17:00:03 sheldonh Exp $
31  */
32 
33 #include "defs.h"
34 #include "pathnames.h"
35 
36 struct interface *ifnet;		/* all interfaces */
37 
38 /* hash table for all interfaces, big enough to tolerate ridiculous
39  * numbers of IP aliases.  Crazy numbers of aliases such as 7000
40  * still will not do well, but not just in looking up interfaces
41  * by name or address.
42  */
43 #define AHASH_LEN 211			/* must be prime */
44 #define AHASH(a) &ahash_tbl[(a)%AHASH_LEN]
45 struct interface *ahash_tbl[AHASH_LEN];
46 
47 #define BHASH_LEN 211			/* must be prime */
48 #define BHASH(a) &bhash_tbl[(a)%BHASH_LEN]
49 struct interface *bhash_tbl[BHASH_LEN];
50 
51 struct interface *remote_if;		/* remote interfaces */
52 
53 /* hash for physical interface names.
54  * Assume there are never more 100 or 200 real interfaces, and that
55  * aliases are put on the end of the hash chains.
56  */
57 #define NHASH_LEN 97
58 struct interface *nhash_tbl[NHASH_LEN];
59 
60 int	tot_interfaces;			/* # of remote and local interfaces */
61 int	rip_interfaces;			/* # of interfaces doing RIP */
62 int	foundloopback;			/* valid flag for loopaddr */
63 naddr	loopaddr;			/* our address on loopback */
64 struct	rt_spare loop_rts;
65 
66 struct timeval ifinit_timer;
67 static struct timeval last_ifinit;
68 #define IF_RESCAN_DELAY() (last_ifinit.tv_sec == now.tv_sec		\
69 			   && last_ifinit.tv_usec == now.tv_usec	\
70 			   && timercmp(&ifinit_timer, &now, >))
71 
72 int	have_ripv1_out;			/* have a RIPv1 interface */
73 int	have_ripv1_in;
74 
75 
76 static struct interface**
77 nhash(char *p)
78 {
79 	u_int i;
80 
81 	for (i = 0; *p != '\0'; p++) {
82 		i = ((i<<1) & 0x7fffffff) | ((i>>31) & 1);
83 		i ^= *p;
84 	}
85 	return &nhash_tbl[i % NHASH_LEN];
86 }
87 
88 
89 /* Link a new interface into the lists and hash tables.
90  */
91 void
92 if_link(struct interface *ifp)
93 {
94 	struct interface **hifp;
95 
96 	ifp->int_prev = &ifnet;
97 	ifp->int_next = ifnet;
98 	if (ifnet != NULL)
99 		ifnet->int_prev = &ifp->int_next;
100 	ifnet = ifp;
101 
102 	hifp = AHASH(ifp->int_addr);
103 	ifp->int_ahash_prev = hifp;
104 	if ((ifp->int_ahash = *hifp) != NULL)
105 		(*hifp)->int_ahash_prev = &ifp->int_ahash;
106 	*hifp = ifp;
107 
108 	if (ifp->int_if_flags & IFF_BROADCAST) {
109 		hifp = BHASH(ifp->int_brdaddr);
110 		ifp->int_bhash_prev = hifp;
111 		if ((ifp->int_bhash = *hifp) != NULL)
112 			(*hifp)->int_bhash_prev = &ifp->int_bhash;
113 		*hifp = ifp;
114 	}
115 
116 	if (ifp->int_state & IS_REMOTE) {
117 		ifp->int_rlink_prev = &remote_if;
118 		ifp->int_rlink = remote_if;
119 		if (remote_if != NULL)
120 			remote_if->int_rlink_prev = &ifp->int_rlink;
121 		remote_if = ifp;
122 	}
123 
124 	hifp = nhash(ifp->int_name);
125 	if (ifp->int_state & IS_ALIAS) {
126 		/* put aliases on the end of the hash chain */
127 		while (*hifp != NULL)
128 			hifp = &(*hifp)->int_nhash;
129 	}
130 	ifp->int_nhash_prev = hifp;
131 	if ((ifp->int_nhash = *hifp) != NULL)
132 		(*hifp)->int_nhash_prev = &ifp->int_nhash;
133 	*hifp = ifp;
134 }
135 
136 
137 /* Find the interface with an address
138  */
139 struct interface *
140 ifwithaddr(naddr addr,
141 	   int	bcast,			/* notice IFF_BROADCAST address */
142 	   int	remote)			/* include IS_REMOTE interfaces */
143 {
144 	struct interface *ifp, *possible = NULL;
145 
146 	remote = (remote == 0) ? IS_REMOTE : 0;
147 
148 	for (ifp = *AHASH(addr); ifp; ifp = ifp->int_ahash) {
149 		if (ifp->int_addr != addr)
150 			continue;
151 		if ((ifp->int_state & remote) != 0)
152 			continue;
153 		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
154 			return ifp;
155 		possible = ifp;
156 	}
157 
158 	if (possible || !bcast)
159 		return possible;
160 
161 	for (ifp = *BHASH(addr); ifp; ifp = ifp->int_bhash) {
162 		if (ifp->int_brdaddr != addr)
163 			continue;
164 		if ((ifp->int_state & remote) != 0)
165 			continue;
166 		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
167 			return ifp;
168 		possible = ifp;
169 	}
170 
171 	return possible;
172 }
173 
174 
175 /* find the interface with a name
176  */
177 struct interface *
178 ifwithname(char *name,			/* "ec0" or whatever */
179 	   naddr addr)			/* 0 or network address */
180 {
181 	struct interface *ifp;
182 
183 	for (;;) {
184 		for (ifp = *nhash(name); ifp != NULL; ifp = ifp->int_nhash) {
185 			/* If the network address is not specified,
186 			 * ignore any alias interfaces.  Otherwise, look
187 			 * for the interface with the target name and address.
188 			 */
189 			if (!strcmp(ifp->int_name, name)
190 			    && ((addr == 0 && !(ifp->int_state & IS_ALIAS))
191 				|| (ifp->int_addr == addr)))
192 				return ifp;
193 		}
194 
195 		/* If there is no known interface, maybe there is a
196 		 * new interface.  So just once look for new interfaces.
197 		 */
198 		if (IF_RESCAN_DELAY())
199 			return 0;
200 		ifinit();
201 	}
202 }
203 
204 
205 struct interface *
206 ifwithindex(u_short idx, int rescan_ok)
207 {
208 	struct interface *ifp;
209 
210 	for (;;) {
211 		for (ifp = ifnet; NULL != ifp; ifp = ifp->int_next) {
212 			if (ifp->int_index == idx)
213 				return ifp;
214 		}
215 
216 		/* If there is no known interface, maybe there is a
217 		 * new interface.  So just once look for new interfaces.
218 		 */
219 		if (!rescan_ok
220 		    || IF_RESCAN_DELAY())
221 			return 0;
222 		ifinit();
223 	}
224 }
225 
226 
227 /* Find an interface from which the specified address
228  * should have come from.  Used for figuring out which
229  * interface a packet came in on.
230  */
231 struct interface *
232 iflookup(naddr addr)
233 {
234 	struct interface *ifp, *maybe;
235 
236 	maybe = NULL;
237 	for (;;) {
238 		for (ifp = ifnet; ifp; ifp = ifp->int_next) {
239 			if (ifp->int_if_flags & IFF_POINTOPOINT) {
240 				/* finished with a match */
241 				if (ifp->int_dstaddr == addr)
242 					return ifp;
243 
244 			} else {
245 				/* finished with an exact match */
246 				if (ifp->int_addr == addr)
247 					return ifp;
248 
249 				/* Look for the longest approximate match.
250 				 */
251 				if (on_net(addr, ifp->int_net, ifp->int_mask)
252 				    && (maybe == NULL
253 					|| ifp->int_mask > maybe->int_mask))
254 					maybe = ifp;
255 			}
256 		}
257 
258 		if (maybe != NULL
259 		    || IF_RESCAN_DELAY())
260 			return maybe;
261 
262 		/* If there is no known interface, maybe there is a
263 		 * new interface.  So just once look for new interfaces.
264 		 */
265 		ifinit();
266 	}
267 }
268 
269 
270 /* Return the classical netmask for an IP address.
271  */
272 naddr					/* host byte order */
273 std_mask(naddr addr)			/* network byte order */
274 {
275 	addr = ntohl(addr);		/* was a host, not a network */
276 
277 	if (addr == 0)			/* default route has mask 0 */
278 		return 0;
279 	if (IN_CLASSA(addr))
280 		return IN_CLASSA_NET;
281 	if (IN_CLASSB(addr))
282 		return IN_CLASSB_NET;
283 	return IN_CLASSC_NET;
284 }
285 
286 
287 /* Find the netmask that would be inferred by RIPv1 listeners
288  *	on the given interface for a given network.
289  *	If no interface is specified, look for the best fitting	interface.
290  */
291 naddr
292 ripv1_mask_net(naddr addr,		/* in network byte order */
293 	       struct interface *ifp)	/* as seen on this interface */
294 {
295 	struct r1net *r1p;
296 	naddr mask = 0;
297 
298 	if (addr == 0)			/* default always has 0 mask */
299 		return mask;
300 
301 	if (ifp != NULL && ifp->int_ripv1_mask != HOST_MASK) {
302 		/* If the target network is that of the associated interface
303 		 * on which it arrived, then use the netmask of the interface.
304 		 */
305 		if (on_net(addr, ifp->int_net, ifp->int_std_mask))
306 			mask = ifp->int_ripv1_mask;
307 
308 	} else {
309 		/* Examine all interfaces, and if it the target seems
310 		 * to have the same network number of an interface, use the
311 		 * netmask of that interface.  If there is more than one
312 		 * such interface, prefer the interface with the longest
313 		 * match.
314 		 */
315 		for (ifp = ifnet; ifp != NULL; ifp = ifp->int_next) {
316 			if (on_net(addr, ifp->int_std_net, ifp->int_std_mask)
317 			    && ifp->int_ripv1_mask > mask
318 			    && ifp->int_ripv1_mask != HOST_MASK)
319 				mask = ifp->int_ripv1_mask;
320 		}
321 
322 	}
323 
324 	/* check special definitions */
325 	if (mask == 0) {
326 		for (r1p = r1nets; r1p != NULL; r1p = r1p->r1net_next) {
327 			if (on_net(addr, r1p->r1net_net, r1p->r1net_match)
328 			    && r1p->r1net_mask > mask)
329 				mask = r1p->r1net_mask;
330 		}
331 
332 		/* Otherwise, make the classic A/B/C guess.
333 		 */
334 		if (mask == 0)
335 			mask = std_mask(addr);
336 	}
337 
338 	return mask;
339 }
340 
341 
342 naddr
343 ripv1_mask_host(naddr addr,		/* in network byte order */
344 		struct interface *ifp)	/* as seen on this interface */
345 {
346 	naddr mask = ripv1_mask_net(addr, ifp);
347 
348 
349 	/* If the computed netmask does not mask the address,
350 	 * then assume it is a host address
351 	 */
352 	if ((ntohl(addr) & ~mask) != 0)
353 		mask = HOST_MASK;
354 	return mask;
355 }
356 
357 
358 /* See if a IP address looks reasonable as a destination
359  */
360 int					/* 0=bad */
361 check_dst(naddr addr)
362 {
363 	addr = ntohl(addr);
364 
365 	if (IN_CLASSA(addr)) {
366 		if (addr == 0)
367 			return 1;	/* default */
368 
369 		addr >>= IN_CLASSA_NSHIFT;
370 		return (addr != 0 && addr != IN_LOOPBACKNET);
371 	}
372 
373 	return (IN_CLASSB(addr) || IN_CLASSC(addr));
374 }
375 
376 
377 /* See a new interface duplicates an existing interface.
378  */
379 struct interface *
380 check_dup(naddr addr,			/* IP address, so network byte order */
381 	  naddr dstaddr,		/* ditto */
382 	  naddr mask,			/* mask, so host byte order */
383 	  int if_flags)
384 {
385 	struct interface *ifp;
386 
387 	for (ifp = ifnet; NULL != ifp; ifp = ifp->int_next) {
388 		if (ifp->int_mask != mask)
389 			continue;
390 
391 		if (!iff_up(ifp->int_if_flags))
392 			continue;
393 
394 		/* The local address can only be shared with a point-to-point
395 		 * link.
396 		 */
397 		if (ifp->int_addr == addr
398 		    && (((if_flags|ifp->int_if_flags) & IFF_POINTOPOINT) == 0))
399 			return ifp;
400 
401 		if (on_net(ifp->int_dstaddr, ntohl(dstaddr),mask))
402 			return ifp;
403 	}
404 	return 0;
405 }
406 
407 
408 /* See that a remote gateway is reachable.
409  *	Note that the answer can change as real interfaces come and go.
410  */
411 int					/* 0=bad */
412 check_remote(struct interface *ifp)
413 {
414 	struct rt_entry *rt;
415 
416 	/* do not worry about other kinds */
417 	if (!(ifp->int_state & IS_REMOTE))
418 	    return 1;
419 
420 	rt = rtfind(ifp->int_addr);
421 	if (rt != NULL
422 	    && rt->rt_ifp != 0
423 	    &&on_net(ifp->int_addr,
424 		     rt->rt_ifp->int_net, rt->rt_ifp->int_mask))
425 		return 1;
426 
427 	/* the gateway cannot be reached directly from one of our
428 	 * interfaces
429 	 */
430 	if (!(ifp->int_state & IS_BROKE)) {
431 		msglog("unreachable gateway %s in "_PATH_GATEWAYS,
432 		       naddr_ntoa(ifp->int_addr));
433 		if_bad(ifp);
434 	}
435 	return 0;
436 }
437 
438 
439 /* Delete an interface.
440  */
441 static void
442 ifdel(struct interface *ifp)
443 {
444 	struct ip_mreq m;
445 	struct interface *ifp1;
446 
447 
448 	trace_if("Del", ifp);
449 
450 	ifp->int_state |= IS_BROKE;
451 
452 	/* unlink the interface
453 	 */
454 	*ifp->int_prev = ifp->int_next;
455 	if (ifp->int_next != 0)
456 		ifp->int_next->int_prev = ifp->int_prev;
457 	*ifp->int_ahash_prev = ifp->int_ahash;
458 	if (ifp->int_ahash != 0)
459 		ifp->int_ahash->int_ahash_prev = ifp->int_ahash_prev;
460 	*ifp->int_nhash_prev = ifp->int_nhash;
461 	if (ifp->int_nhash != 0)
462 		ifp->int_nhash->int_nhash_prev = ifp->int_nhash_prev;
463 	if (ifp->int_if_flags & IFF_BROADCAST) {
464 		*ifp->int_bhash_prev = ifp->int_bhash;
465 		if (ifp->int_bhash != 0)
466 			ifp->int_bhash->int_bhash_prev = ifp->int_bhash_prev;
467 	}
468 	if (ifp->int_state & IS_REMOTE) {
469 		*ifp->int_rlink_prev = ifp->int_rlink;
470 		if (ifp->int_rlink != 0)
471 			ifp->int_rlink->int_rlink_prev = ifp->int_rlink_prev;
472 	}
473 
474 	if (!(ifp->int_state & IS_ALIAS)) {
475 		/* delete aliases when the main interface dies
476 		 */
477 		for (ifp1 = ifnet; NULL != ifp1; ifp1 = ifp1->int_next) {
478 			if (ifp1 != ifp
479 			    && !strcmp(ifp->int_name, ifp1->int_name))
480 				ifdel(ifp1);
481 		}
482 
483 		if ((ifp->int_if_flags & IFF_MULTICAST)
484 #ifdef MCAST_PPP_BUG
485 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
486 #endif
487 		    && rip_sock >= 0) {
488 			m.imr_multiaddr.s_addr = htonl(INADDR_RIP_GROUP);
489 			m.imr_interface.s_addr = ((ifp->int_if_flags
490 						   & IFF_POINTOPOINT)
491 						  ? ifp->int_dstaddr
492 						  : ifp->int_addr);
493 			if (setsockopt(rip_sock,IPPROTO_IP,IP_DROP_MEMBERSHIP,
494 				       &m, sizeof(m)) < 0
495 			    && errno != EADDRNOTAVAIL
496 			    && !TRACEACTIONS)
497 				LOGERR("setsockopt(IP_DROP_MEMBERSHIP RIP)");
498 			if (rip_sock_mcast == ifp)
499 				rip_sock_mcast = 0;
500 		}
501 		if (ifp->int_rip_sock >= 0) {
502 			close(ifp->int_rip_sock);
503 			ifp->int_rip_sock = -1;
504 			fix_select();
505 		}
506 
507 		tot_interfaces--;
508 		if (!IS_RIP_OFF(ifp->int_state))
509 			rip_interfaces--;
510 
511 		/* Zap all routes associated with this interface.
512 		 * Assume routes just using gateways beyond this interface
513 		 * will timeout naturally, and have probably already died.
514 		 */
515 		rn_walktree(rhead, walk_bad, 0);
516 
517 		set_rdisc_mg(ifp, 0);
518 		if_bad_rdisc(ifp);
519 	}
520 
521 	free(ifp);
522 }
523 
524 
525 /* Mark an interface ill.
526  */
527 void
528 if_sick(struct interface *ifp)
529 {
530 	if (0 == (ifp->int_state & (IS_SICK | IS_BROKE))) {
531 		ifp->int_state |= IS_SICK;
532 		ifp->int_act_time = NEVER;
533 		trace_if("Chg", ifp);
534 
535 		LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
536 	}
537 }
538 
539 
540 /* Mark an interface dead.
541  */
542 void
543 if_bad(struct interface *ifp)
544 {
545 	struct interface *ifp1;
546 
547 
548 	if (ifp->int_state & IS_BROKE)
549 		return;
550 
551 	LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
552 
553 	ifp->int_state |= (IS_BROKE | IS_SICK);
554 	ifp->int_act_time = NEVER;
555 	ifp->int_query_time = NEVER;
556 	ifp->int_data.ts = now.tv_sec;
557 
558 	trace_if("Chg", ifp);
559 
560 	if (!(ifp->int_state & IS_ALIAS)) {
561 		for (ifp1 = ifnet; NULL != ifp1; ifp1 = ifp1->int_next) {
562 			if (ifp1 != ifp
563 			    && !strcmp(ifp->int_name, ifp1->int_name))
564 				if_bad(ifp1);
565 		}
566 		rn_walktree(rhead, walk_bad, 0);
567 		if_bad_rdisc(ifp);
568 	}
569 }
570 
571 
572 /* Mark an interface alive
573  */
574 int					/* 1=it was dead */
575 if_ok(struct interface *ifp,
576       const char *type)
577 {
578 	struct interface *ifp1;
579 
580 
581 	if (!(ifp->int_state & IS_BROKE)) {
582 		if (ifp->int_state & IS_SICK) {
583 			trace_act("%sinterface %s to %s working better",
584 				  type,
585 				  ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
586 			ifp->int_state &= ~IS_SICK;
587 		}
588 		return 0;
589 	}
590 
591 	msglog("%sinterface %s to %s restored",
592 	       type, ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
593 	ifp->int_state &= ~(IS_BROKE | IS_SICK);
594 	ifp->int_data.ts = 0;
595 
596 	if (!(ifp->int_state & IS_ALIAS)) {
597 		for (ifp1 = ifnet; NULL != ifp1; ifp1 = ifp1->int_next) {
598 			if (ifp1 != ifp
599 			    && !strcmp(ifp->int_name, ifp1->int_name))
600 				if_ok(ifp1, type);
601 		}
602 		if_ok_rdisc(ifp);
603 	}
604 
605 	if (ifp->int_state & IS_REMOTE) {
606 		if (!addrouteforif(ifp))
607 			return 0;
608 	}
609 	return 1;
610 }
611 
612 
613 /* disassemble routing message
614  */
615 void
616 rt_xaddrs(struct rt_addrinfo *info,
617 	  struct sockaddr *sa,
618 	  struct sockaddr *lim,
619 	  int addrs)
620 {
621 	int i;
622 #ifdef _HAVE_SA_LEN
623 	static struct sockaddr sa_zero;
624 #endif
625 #define ROUNDUP(a) RT_ROUNDUP(a)
626 
627 
628 	memset(info, 0, sizeof(*info));
629 	info->rti_addrs = addrs;
630 	for (i = 0; i < RTAX_MAX && sa < lim; i++) {
631 		if ((addrs & (1 << i)) == 0)
632 			continue;
633 #ifdef _HAVE_SA_LEN
634 		info->rti_info[i] = (sa->sa_len != 0) ? sa : &sa_zero;
635 		sa = (struct sockaddr *)((char*)(sa)
636 					 + ROUNDUP(sa->sa_len));
637 #else
638 		info->rti_info[i] = sa;
639 		sa = (struct sockaddr *)((char*)(sa)
640 					 + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
641 #endif
642 	}
643 }
644 
645 
646 /* Find the network interfaces which have configured themselves.
647  *	This must be done regularly, if only for extra addresses
648  *	that come and go on interfaces.
649  */
650 void
651 ifinit(void)
652 {
653 	static char *sysctl_buf;
654 	static size_t sysctl_buf_size = 0;
655 	uint complaints = 0;
656 	static u_int prev_complaints = 0;
657 #	define COMP_NOT_INET	0x001
658 #	define COMP_NOADDR	0x002
659 #	define COMP_BADADDR	0x004
660 #	define COMP_NODST	0x008
661 #	define COMP_NOBADR	0x010
662 #	define COMP_NOMASK	0x020
663 #	define COMP_DUP		0x040
664 #	define COMP_BAD_METRIC	0x080
665 #	define COMP_NETMASK	0x100
666 
667 	struct interface ifs, ifs0, *ifp, *ifp1;
668 	struct rt_entry *rt;
669 	size_t needed;
670 	int mib[6];
671 	struct if_msghdr *ifm;
672 	struct ifa_msghdr *ifam, *ifam_lim, *ifam2;
673 	int in, ierr, out, oerr;
674 	struct intnet *intnetp;
675 	struct rt_addrinfo info;
676 #ifdef SIOCGIFMETRIC
677 	struct ifreq ifr;
678 #endif
679 
680 
681 	last_ifinit = now;
682 	ifinit_timer.tv_sec = now.tv_sec + (supplier
683 					    ? CHECK_ACT_INTERVAL
684 					    : CHECK_QUIET_INTERVAL);
685 
686 	/* mark all interfaces so we can get rid of those that disappear */
687 	for (ifp = ifnet; NULL != ifp; ifp = ifp->int_next)
688 		ifp->int_state &= ~(IS_CHECKED | IS_DUP);
689 
690 	/* Fetch the interface list, without too many system calls
691 	 * since we do it repeatedly.
692 	 */
693 	mib[0] = CTL_NET;
694 	mib[1] = PF_ROUTE;
695 	mib[2] = 0;
696 	mib[3] = AF_INET;
697 	mib[4] = NET_RT_IFLIST;
698 	mib[5] = 0;
699 	for (;;) {
700 		if ((needed = sysctl_buf_size) != 0) {
701 			if (sysctl(mib, 6, sysctl_buf,&needed, 0, 0) >= 0)
702 				break;
703 			/* retry if the table grew */
704 			if (errno != ENOMEM && errno != EFAULT)
705 				BADERR(1, "ifinit: sysctl(RT_IFLIST)");
706 			free(sysctl_buf);
707 			needed = 0;
708 		}
709 		if (sysctl(mib, 6, 0, &needed, 0, 0) < 0)
710 			BADERR(1,"ifinit: sysctl(RT_IFLIST) estimate");
711 		sysctl_buf = rtmalloc(sysctl_buf_size = needed,
712 				      "ifinit sysctl");
713 	}
714 
715 	ifam_lim = (struct ifa_msghdr *)(sysctl_buf + needed);
716 	for (ifam = (struct ifa_msghdr *)sysctl_buf;
717 	     ifam < ifam_lim;
718 	     ifam = ifam2) {
719 
720 		ifam2 = (struct ifa_msghdr*)((char*)ifam + ifam->ifam_msglen);
721 
722 		if (ifam->ifam_type == RTM_IFINFO) {
723 			struct sockaddr_dl *sdl;
724 
725 			ifm = (struct if_msghdr *)ifam;
726 			/* make prototype structure for the IP aliases
727 			 */
728 			memset(&ifs0, 0, sizeof(ifs0));
729 			ifs0.int_rip_sock = -1;
730 			ifs0.int_index = ifm->ifm_index;
731 			ifs0.int_if_flags = ifm->ifm_flags;
732 			ifs0.int_state = IS_CHECKED;
733 			ifs0.int_query_time = NEVER;
734 			ifs0.int_act_time = now.tv_sec;
735 			ifs0.int_data.ts = now.tv_sec;
736 			ifs0.int_data.ipackets = ifm->ifm_data.ifi_ipackets;
737 			ifs0.int_data.ierrors = ifm->ifm_data.ifi_ierrors;
738 			ifs0.int_data.opackets = ifm->ifm_data.ifi_opackets;
739 			ifs0.int_data.oerrors = ifm->ifm_data.ifi_oerrors;
740 			sdl = (struct sockaddr_dl *)(ifm + 1);
741 			sdl->sdl_data[sdl->sdl_nlen] = 0;
742 			strncpy(ifs0.int_name, sdl->sdl_data,
743 				MIN(sizeof(ifs0.int_name), sdl->sdl_nlen));
744 			continue;
745 		}
746 		if (ifam->ifam_type != RTM_NEWADDR) {
747 			logbad(1,"ifinit: out of sync");
748 			continue;
749 		}
750 		rt_xaddrs(&info, (struct sockaddr *)(ifam+1),
751 			  (struct sockaddr *)ifam2,
752 			  ifam->ifam_addrs);
753 
754 		/* Prepare for the next address of this interface, which
755 		 * will be an alias.
756 		 * Do not output RIP or Router-Discovery packets via aliases.
757 		 */
758 		memcpy(&ifs, &ifs0, sizeof(ifs));
759 		ifs0.int_state |= (IS_ALIAS | IS_NO_RIP_OUT | IS_NO_RDISC);
760 
761 		if (INFO_IFA(&info) == 0) {
762 			if (iff_up(ifs.int_if_flags)) {
763 				if (!(prev_complaints & COMP_NOADDR))
764 					msglog("%s has no address",
765 					       ifs.int_name);
766 				complaints |= COMP_NOADDR;
767 			}
768 			continue;
769 		}
770 		if (INFO_IFA(&info)->sa_family != AF_INET) {
771 			if (iff_up(ifs.int_if_flags)) {
772 				if (!(prev_complaints & COMP_NOT_INET))
773 					trace_act("%s: not AF_INET",
774 						  ifs.int_name);
775 				complaints |= COMP_NOT_INET;
776 			}
777 			continue;
778 		}
779 
780 		ifs.int_addr = S_ADDR(INFO_IFA(&info));
781 
782 		if (ntohl(ifs.int_addr)>>24 == 0
783 		    || ntohl(ifs.int_addr)>>24 == 0xff) {
784 			if (iff_up(ifs.int_if_flags)) {
785 				if (!(prev_complaints & COMP_BADADDR))
786 					msglog("%s has a bad address",
787 					       ifs.int_name);
788 				complaints |= COMP_BADADDR;
789 			}
790 			continue;
791 		}
792 
793 		if (ifs.int_if_flags & IFF_LOOPBACK) {
794 			ifs.int_state |= IS_PASSIVE | IS_NO_RIP | IS_NO_RDISC;
795 			ifs.int_dstaddr = ifs.int_addr;
796 			ifs.int_mask = HOST_MASK;
797 			ifs.int_ripv1_mask = HOST_MASK;
798 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
799 			ifs.int_net = ntohl(ifs.int_dstaddr);
800 			if (!foundloopback) {
801 				foundloopback = 1;
802 				loopaddr = ifs.int_addr;
803 				loop_rts.rts_gate = loopaddr;
804 				loop_rts.rts_router = loopaddr;
805 			}
806 
807 		} else if (ifs.int_if_flags & IFF_POINTOPOINT) {
808 			if (INFO_BRD(&info) == 0
809 			    || INFO_BRD(&info)->sa_family != AF_INET) {
810 				if (iff_up(ifs.int_if_flags)) {
811 					if (!(prev_complaints & COMP_NODST))
812 						msglog("%s has a bad"
813 						       " destination address",
814 						       ifs.int_name);
815 					complaints |= COMP_NODST;
816 				}
817 				continue;
818 			}
819 			ifs.int_dstaddr = S_ADDR(INFO_BRD(&info));
820 			if (ntohl(ifs.int_dstaddr)>>24 == 0
821 			    || ntohl(ifs.int_dstaddr)>>24 == 0xff) {
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_mask = HOST_MASK;
832 			ifs.int_ripv1_mask = ntohl(S_ADDR(INFO_MASK(&info)));
833 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
834 			ifs.int_net = ntohl(ifs.int_dstaddr);
835 
836 		}  else {
837 			if (INFO_MASK(&info) == 0) {
838 				if (iff_up(ifs.int_if_flags)) {
839 					if (!(prev_complaints & COMP_NOMASK))
840 						msglog("%s has no netmask",
841 						       ifs.int_name);
842 					complaints |= COMP_NOMASK;
843 				}
844 				continue;
845 			}
846 			ifs.int_dstaddr = ifs.int_addr;
847 			ifs.int_mask = ntohl(S_ADDR(INFO_MASK(&info)));
848 			ifs.int_ripv1_mask = ifs.int_mask;
849 			ifs.int_std_mask = std_mask(ifs.int_addr);
850 			ifs.int_net = ntohl(ifs.int_addr) & ifs.int_mask;
851 			if (ifs.int_mask != ifs.int_std_mask)
852 				ifs.int_state |= IS_SUBNET;
853 
854 			if (ifs.int_if_flags & IFF_BROADCAST) {
855 				if (INFO_BRD(&info) == 0) {
856 					if (iff_up(ifs.int_if_flags)) {
857 					    if (!(prev_complaints
858 						  & COMP_NOBADR))
859 						msglog("%s has"
860 						       "no broadcast address",
861 						       ifs.int_name);
862 					    complaints |= COMP_NOBADR;
863 					}
864 					continue;
865 				}
866 				ifs.int_brdaddr = S_ADDR(INFO_BRD(&info));
867 			}
868 		}
869 		ifs.int_std_net = ifs.int_net & ifs.int_std_mask;
870 		ifs.int_std_addr = htonl(ifs.int_std_net);
871 
872 		/* Use a minimum metric of one.  Treat the interface metric
873 		 * (default 0) as an increment to the hop count of one.
874 		 *
875 		 * The metric obtained from the routing socket dump of
876 		 * interface addresses is wrong.  It is not set by the
877 		 * SIOCSIFMETRIC ioctl.
878 		 */
879 #ifdef SIOCGIFMETRIC
880 		strncpy(ifr.ifr_name, ifs.int_name, sizeof(ifr.ifr_name));
881 		if (ioctl(rt_sock, SIOCGIFMETRIC, &ifr) < 0) {
882 			DBGERR(1, "ioctl(SIOCGIFMETRIC)");
883 			ifs.int_metric = 0;
884 		} else {
885 			ifs.int_metric = ifr.ifr_metric;
886 		}
887 #else
888 		ifs.int_metric = ifam->ifam_metric;
889 #endif
890 		if (ifs.int_metric > HOPCNT_INFINITY) {
891 			ifs.int_metric = 0;
892 			if (!(prev_complaints & COMP_BAD_METRIC)
893 			    && iff_up(ifs.int_if_flags)) {
894 				complaints |= COMP_BAD_METRIC;
895 				msglog("%s has a metric of %d",
896 				       ifs.int_name, ifs.int_metric);
897 			}
898 		}
899 
900 		/* See if this is a familiar interface.
901 		 * If so, stop worrying about it if it is the same.
902 		 * Start it over if it now is to somewhere else, as happens
903 		 * frequently with PPP and SLIP.
904 		 */
905 		ifp = ifwithname(ifs.int_name, ((ifs.int_state & IS_ALIAS)
906 						? ifs.int_addr
907 						: 0));
908 		if (ifp != NULL) {
909 			ifp->int_state |= IS_CHECKED;
910 
911 			if (0 != ((ifp->int_if_flags ^ ifs.int_if_flags)
912 				  & (IFF_BROADCAST
913 				     | IFF_LOOPBACK
914 				     | IFF_POINTOPOINT
915 				     | IFF_MULTICAST))
916 			    || 0 != ((ifp->int_state ^ ifs.int_state)
917 				     & IS_ALIAS)
918 			    || ifp->int_addr != ifs.int_addr
919 			    || ifp->int_brdaddr != ifs.int_brdaddr
920 			    || ifp->int_dstaddr != ifs.int_dstaddr
921 			    || ifp->int_mask != ifs.int_mask
922 			    || ifp->int_metric != ifs.int_metric) {
923 				/* Forget old information about
924 				 * a changed interface.
925 				 */
926 				trace_act("interface %s has changed",
927 					  ifp->int_name);
928 				ifdel(ifp);
929 				ifp = NULL;
930 			}
931 		}
932 
933 		if (ifp != NULL) {
934 			/* The primary representative of an alias worries
935 			 * about how things are working.
936 			 */
937 			if (ifp->int_state & IS_ALIAS)
938 				continue;
939 
940 			/* note interfaces that have been turned off
941 			 */
942 			if (!iff_up(ifs.int_if_flags)) {
943 				if (iff_up(ifp->int_if_flags)) {
944 					msglog("interface %s to %s turned off",
945 					       ifp->int_name,
946 					       naddr_ntoa(ifp->int_dstaddr));
947 					if_bad(ifp);
948 					ifp->int_if_flags &= ~IFF_UP;
949 				} else if (now.tv_sec>(ifp->int_data.ts
950 						       + CHECK_BAD_INTERVAL)) {
951 					trace_act("interface %s has been off"
952 						  " %ld seconds; forget it",
953 						  ifp->int_name,
954 						  now.tv_sec-ifp->int_data.ts);
955 					ifdel(ifp);
956 				}
957 				continue;
958 			}
959 			/* or that were off and are now ok */
960 			if (!iff_up(ifp->int_if_flags)) {
961 				ifp->int_if_flags |= IFF_UP;
962 				if_ok(ifp, "");
963 			}
964 
965 			/* If it has been long enough,
966 			 * see if the interface is broken.
967 			 */
968 			if (now.tv_sec < ifp->int_data.ts+CHECK_BAD_INTERVAL)
969 				continue;
970 
971 			in = ifs.int_data.ipackets - ifp->int_data.ipackets;
972 			ierr = ifs.int_data.ierrors - ifp->int_data.ierrors;
973 			out = ifs.int_data.opackets - ifp->int_data.opackets;
974 			oerr = ifs.int_data.oerrors - ifp->int_data.oerrors;
975 			/* If the interface just awoke, restart the counters.
976 			 */
977 			if (ifp->int_data.ts == 0) {
978 				ifp->int_data = ifs.int_data;
979 				continue;
980 			}
981 			ifp->int_data = ifs.int_data;
982 
983 			/* Withhold judgment when the short error
984 			 * counters wrap or the interface is reset.
985 			 */
986 			if (ierr < 0 || in < 0 || oerr < 0 || out < 0) {
987 				LIM_SEC(ifinit_timer,
988 					now.tv_sec+CHECK_BAD_INTERVAL);
989 				continue;
990 			}
991 
992 			/* Withhold judgement when there is no traffic
993 			 */
994 			if (in == 0 && out == 0 && ierr == 0 && oerr == 0)
995 				continue;
996 
997 			/* It is bad if input or output is not working.
998 			 * Require presistent problems before marking it dead.
999 			 */
1000 			if ((in <= ierr && ierr > 0)
1001 			    || (out <= oerr && oerr > 0)) {
1002 				if (!(ifp->int_state & IS_SICK)) {
1003 					trace_act("interface %s to %s"
1004 						  " sick: in=%d ierr=%d"
1005 						  " out=%d oerr=%d",
1006 						  ifp->int_name,
1007 						  naddr_ntoa(ifp->int_dstaddr),
1008 						  in, ierr, out, oerr);
1009 					if_sick(ifp);
1010 					continue;
1011 				}
1012 				if (!(ifp->int_state & IS_BROKE)) {
1013 					msglog("interface %s to %s broken:"
1014 					       " in=%d ierr=%d out=%d oerr=%d",
1015 					       ifp->int_name,
1016 					       naddr_ntoa(ifp->int_dstaddr),
1017 					       in, ierr, out, oerr);
1018 					if_bad(ifp);
1019 				}
1020 				continue;
1021 			}
1022 
1023 			/* otherwise, it is active and healthy
1024 			 */
1025 			ifp->int_act_time = now.tv_sec;
1026 			if_ok(ifp, "");
1027 			continue;
1028 		}
1029 
1030 		/* This is a new interface.
1031 		 * If it is dead, forget it.
1032 		 */
1033 		if (!iff_up(ifs.int_if_flags))
1034 			continue;
1035 
1036 		/* If it duplicates an existing interface,
1037 		 * complain about it, mark the other one
1038 		 * duplicated, and forget this one.
1039 		 */
1040 		ifp = check_dup(ifs.int_addr,ifs.int_dstaddr,ifs.int_mask,
1041 				ifs.int_if_flags);
1042 		if (ifp != NULL) {
1043 			/* Ignore duplicates of itself, caused by having
1044 			 * IP aliases on the same network.
1045 			 */
1046 			if (!strcmp(ifp->int_name, ifs.int_name))
1047 				continue;
1048 
1049 			if (!(prev_complaints & COMP_DUP)) {
1050 				complaints |= COMP_DUP;
1051 				msglog("%s (%s%s%s) is duplicated by"
1052 				       " %s (%s%s%s)",
1053 				       ifs.int_name,
1054 				       addrname(ifs.int_addr,ifs.int_mask,1),
1055 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1056 					? "-->" : ""),
1057 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1058 					? naddr_ntoa(ifs.int_dstaddr) : ""),
1059 				       ifp->int_name,
1060 				       addrname(ifp->int_addr,ifp->int_mask,1),
1061 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1062 					? "-->" : ""),
1063 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1064 					? naddr_ntoa(ifp->int_dstaddr) : ""));
1065 			}
1066 			ifp->int_state |= IS_DUP;
1067 			continue;
1068 		}
1069 
1070 		if (0 == (ifs.int_if_flags & (IFF_POINTOPOINT | IFF_BROADCAST))
1071 		    && !(ifs.int_state & IS_PASSIVE)) {
1072 			trace_act("%s is neither broadcast, point-to-point,"
1073 				  " nor loopback",
1074 				  ifs.int_name);
1075 			if (!(ifs.int_state & IFF_MULTICAST))
1076 				ifs.int_state |= IS_NO_RDISC;
1077 		}
1078 
1079 
1080 		/* It is new and ok.   Add it to the list of interfaces
1081 		 */
1082 		ifp = (struct interface *)rtmalloc(sizeof(*ifp), "ifinit ifp");
1083 		memcpy(ifp, &ifs, sizeof(*ifp));
1084 		get_parms(ifp);
1085 		if_link(ifp);
1086 		trace_if("Add", ifp);
1087 
1088 		/* Notice likely bad netmask.
1089 		 */
1090 		if (!(prev_complaints & COMP_NETMASK)
1091 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
1092 		    && ifp->int_addr != RIP_DEFAULT) {
1093 			for (ifp1 = ifnet; NULL != ifp1; ifp1 = ifp1->int_next) {
1094 				if (ifp1->int_mask == ifp->int_mask)
1095 					continue;
1096 				if (ifp1->int_if_flags & IFF_POINTOPOINT)
1097 					continue;
1098 				if (ifp1->int_dstaddr == RIP_DEFAULT)
1099 					continue;
1100 				/* ignore aliases on the right network */
1101 				if (!strcmp(ifp->int_name, ifp1->int_name))
1102 					continue;
1103 				if (on_net(ifp->int_dstaddr,
1104 					   ifp1->int_net, ifp1->int_mask)
1105 				    || on_net(ifp1->int_dstaddr,
1106 					      ifp->int_net, ifp->int_mask)) {
1107 					msglog("possible netmask problem"
1108 					       " between %s:%s and %s:%s",
1109 					       ifp->int_name,
1110 					       addrname(htonl(ifp->int_net),
1111 							ifp->int_mask, 1),
1112 					       ifp1->int_name,
1113 					       addrname(htonl(ifp1->int_net),
1114 							ifp1->int_mask, 1));
1115 					complaints |= COMP_NETMASK;
1116 				}
1117 			}
1118 		}
1119 
1120 		if (!(ifp->int_state & IS_ALIAS)) {
1121 			/* Count the # of directly connected networks.
1122 			 */
1123 			if (!(ifp->int_if_flags & IFF_LOOPBACK))
1124 				tot_interfaces++;
1125 			if (!IS_RIP_OFF(ifp->int_state))
1126 				rip_interfaces++;
1127 
1128 			/* turn on router discovery and RIP If needed */
1129 			if_ok_rdisc(ifp);
1130 			rip_on(ifp);
1131 		}
1132 	}
1133 
1134 	/* If we are multi-homed and have at least two interfaces
1135 	 * listening to RIP, then output by default.
1136 	 */
1137 	if (!supplier_set && rip_interfaces > 1)
1138 		set_supplier();
1139 
1140 	/* If we are multi-homed, optionally advertise a route to
1141 	 * our main address.
1142 	 */
1143 	if (advertise_mhome
1144 	    || (tot_interfaces > 1
1145 		&& mhome
1146 		&& (ifp = ifwithaddr(myaddr, 0, 0)) != NULL
1147 		&& foundloopback)) {
1148 		advertise_mhome = 1;
1149 		rt = rtget(myaddr, HOST_MASK);
1150 		if (rt != NULL) {
1151 			if (rt->rt_ifp != ifp
1152 			    || rt->rt_router != loopaddr) {
1153 				rtdelete(rt);
1154 				rt = NULL;
1155 			} else {
1156 				loop_rts.rts_ifp = ifp;
1157 				loop_rts.rts_metric = 0;
1158 				loop_rts.rts_time = rt->rt_time;
1159 				rtchange(rt, rt->rt_state | RS_MHOME,
1160 					 &loop_rts, 0);
1161 			}
1162 		}
1163 		if (rt == NULL) {
1164 			loop_rts.rts_ifp = ifp;
1165 			loop_rts.rts_metric = 0;
1166 			rtadd(myaddr, HOST_MASK, RS_MHOME, &loop_rts);
1167 		}
1168 	}
1169 
1170 	for (ifp = ifnet; ifp != NULL; ifp = ifp1) {
1171 		ifp1 = ifp->int_next;	/* because we may delete it */
1172 
1173 		/* Forget any interfaces that have disappeared.
1174 		 */
1175 		if (!(ifp->int_state & (IS_CHECKED | IS_REMOTE))) {
1176 			trace_act("interface %s has disappeared",
1177 				  ifp->int_name);
1178 			ifdel(ifp);
1179 			continue;
1180 		}
1181 
1182 		if ((ifp->int_state & IS_BROKE)
1183 		    && !(ifp->int_state & IS_PASSIVE))
1184 			LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
1185 
1186 		/* If we ever have a RIPv1 interface, assume we always will.
1187 		 * It might come back if it ever goes away.
1188 		 */
1189 		if (!(ifp->int_state & IS_NO_RIPV1_OUT) && supplier)
1190 			have_ripv1_out = 1;
1191 		if (!(ifp->int_state & IS_NO_RIPV1_IN))
1192 			have_ripv1_in = 1;
1193 	}
1194 
1195 	for (ifp = ifnet; ifp != NULL; ifp = ifp->int_next) {
1196 		/* Ensure there is always a network route for interfaces,
1197 		 * after any dead interfaces have been deleted, which
1198 		 * might affect routes for point-to-point links.
1199 		 */
1200 		if (!addrouteforif(ifp))
1201 			continue;
1202 
1203 		/* Add routes to the local end of point-to-point interfaces
1204 		 * using loopback.
1205 		 */
1206 		if ((ifp->int_if_flags & IFF_POINTOPOINT)
1207 		    && !(ifp->int_state & IS_REMOTE)
1208 		    && foundloopback) {
1209 			/* Delete any routes to the network address through
1210 			 * foreign routers. Remove even static routes.
1211 			 */
1212 			del_static(ifp->int_addr, HOST_MASK, 0, 0);
1213 			rt = rtget(ifp->int_addr, HOST_MASK);
1214 			if (rt != NULL && rt->rt_router != loopaddr) {
1215 				rtdelete(rt);
1216 				rt = NULL;
1217 			}
1218 			if (rt != NULL) {
1219 				if (!(rt->rt_state & RS_LOCAL)
1220 				    || rt->rt_metric > ifp->int_metric) {
1221 					ifp1 = ifp;
1222 				} else {
1223 					ifp1 = rt->rt_ifp;
1224 				}
1225 				loop_rts.rts_ifp = ifp1;
1226 				loop_rts.rts_metric = 0;
1227 				loop_rts.rts_time = rt->rt_time;
1228 				rtchange(rt, ((rt->rt_state & ~RS_NET_SYN)
1229 					      | (RS_IF|RS_LOCAL)),
1230 					 &loop_rts, 0);
1231 			} else {
1232 				loop_rts.rts_ifp = ifp;
1233 				loop_rts.rts_metric = 0;
1234 				rtadd(ifp->int_addr, HOST_MASK,
1235 				      (RS_IF | RS_LOCAL), &loop_rts);
1236 			}
1237 		}
1238 	}
1239 
1240 	/* add the authority routes */
1241 	for (intnetp = intnets; intnetp!=NULL; intnetp = intnetp->intnet_next) {
1242 		rt = rtget(intnetp->intnet_addr, intnetp->intnet_mask);
1243 		if (rt != NULL
1244 		    && !(rt->rt_state & RS_NO_NET_SYN)
1245 		    && !(rt->rt_state & RS_NET_INT)) {
1246 			rtdelete(rt);
1247 			rt = NULL;
1248 		}
1249 		if (rt == NULL) {
1250 			loop_rts.rts_ifp = 0;
1251 			loop_rts.rts_metric = intnetp->intnet_metric-1;
1252 			rtadd(intnetp->intnet_addr, intnetp->intnet_mask,
1253 			      RS_NET_SYN | RS_NET_INT, &loop_rts);
1254 		}
1255 	}
1256 
1257 	prev_complaints = complaints;
1258 }
1259 
1260 
1261 static void
1262 check_net_syn(struct interface *ifp)
1263 {
1264 	struct rt_entry *rt;
1265 	static struct rt_spare new;
1266 
1267 
1268 	/* Turn on the need to automatically synthesize a network route
1269 	 * for this interface only if we are running RIPv1 on some other
1270 	 * interface that is on a different class-A,B,or C network.
1271 	 */
1272 	if (have_ripv1_out || have_ripv1_in) {
1273 		ifp->int_state |= IS_NEED_NET_SYN;
1274 		rt = rtget(ifp->int_std_addr, ifp->int_std_mask);
1275 		if (rt != NULL
1276 		    && 0 == (rt->rt_state & RS_NO_NET_SYN)
1277 		    && (!(rt->rt_state & RS_NET_SYN)
1278 			|| rt->rt_metric > ifp->int_metric)) {
1279 			rtdelete(rt);
1280 			rt = NULL;
1281 		}
1282 		if (rt == NULL) {
1283 			new.rts_ifp = ifp;
1284 			new.rts_gate = ifp->int_addr;
1285 			new.rts_router = ifp->int_addr;
1286 			new.rts_metric = ifp->int_metric;
1287 			rtadd(ifp->int_std_addr, ifp->int_std_mask,
1288 			      RS_NET_SYN, &new);
1289 		}
1290 
1291 	} else {
1292 		ifp->int_state &= ~IS_NEED_NET_SYN;
1293 
1294 		rt = rtget(ifp->int_std_addr,
1295 			   ifp->int_std_mask);
1296 		if (rt != NULL
1297 		    && (rt->rt_state & RS_NET_SYN)
1298 		    && rt->rt_ifp == ifp)
1299 			rtbad_sub(rt);
1300 	}
1301 }
1302 
1303 
1304 /* Add route for interface if not currently installed.
1305  * Create route to other end if a point-to-point link,
1306  * otherwise a route to this (sub)network.
1307  */
1308 int					/* 0=bad interface */
1309 addrouteforif(struct interface *ifp)
1310 {
1311 	struct rt_entry *rt;
1312 	static struct rt_spare new;
1313 	naddr dst;
1314 
1315 
1316 	/* skip sick interfaces
1317 	 */
1318 	if (ifp->int_state & IS_BROKE)
1319 		return 0;
1320 
1321 	/* If the interface on a subnet, then install a RIPv1 route to
1322 	 * the network as well (unless it is sick).
1323 	 */
1324 	if (ifp->int_state & IS_SUBNET)
1325 		check_net_syn(ifp);
1326 
1327 	dst = (0 != (ifp->int_if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK))
1328 	       ? ifp->int_dstaddr
1329 	       : htonl(ifp->int_net));
1330 
1331 	new.rts_ifp = ifp;
1332 	new.rts_router = ifp->int_addr;
1333 	new.rts_gate = ifp->int_addr;
1334 	new.rts_metric = ifp->int_metric;
1335 	new.rts_time = now.tv_sec;
1336 
1337 	/* If we are going to send packets to the gateway,
1338 	 * it must be reachable using our physical interfaces
1339 	 */
1340 	if ((ifp->int_state & IS_REMOTE)
1341 	    && !(ifp->int_state & IS_EXTERNAL)
1342 	    && !check_remote(ifp))
1343 		return 0;
1344 
1345 	/* We are finished if the correct main interface route exists.
1346 	 * The right route must be for the right interface, not synthesized
1347 	 * from a subnet, be a "gateway" or not as appropriate, and so forth.
1348 	 */
1349 	del_static(dst, ifp->int_mask, 0, 0);
1350 	rt = rtget(dst, ifp->int_mask);
1351 	if (rt != NULL) {
1352 		if ((rt->rt_ifp != ifp
1353 		     || rt->rt_router != ifp->int_addr)
1354 		    && (!(ifp->int_state & IS_DUP)
1355 			|| rt->rt_ifp == 0
1356 			|| (rt->rt_ifp->int_state & IS_BROKE))) {
1357 			rtdelete(rt);
1358 			rt = NULL;
1359 		} else {
1360 			rtchange(rt, ((rt->rt_state | RS_IF)
1361 				      & ~(RS_NET_SYN | RS_LOCAL)),
1362 				 &new, 0);
1363 		}
1364 	}
1365 	if (rt == NULL) {
1366 		if (ifp->int_transitions++ > 0)
1367 			trace_act("re-install interface %s",
1368 				  ifp->int_name);
1369 
1370 		rtadd(dst, ifp->int_mask, RS_IF, &new);
1371 	}
1372 
1373 	return 1;
1374 }
1375