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