1/*	$NetBSD: if.c,v 1.29 2010/10/13 09:19:40 martin Exp $	*/
2
3/*
4 * Copyright (c) 1983, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgment:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include "defs.h"
37#include "pathnames.h"
38
39#ifdef __NetBSD__
40__RCSID("$NetBSD: if.c,v 1.29 2010/10/13 09:19:40 martin Exp $");
41#elif defined(__FreeBSD__)
42__RCSID("$FreeBSD$");
43#else
44__RCSID("Revision: 2.27 ");
45#ident "Revision: 2.27 "
46#endif
47
48struct interface *ifnet;		/* all interfaces */
49
50/* hash table for all interfaces, big enough to tolerate ridiculous
51 * numbers of IP aliases.  Crazy numbers of aliases such as 7000
52 * still will not do well, but not just in looking up interfaces
53 * by name or address.
54 */
55#define AHASH_LEN 211			/* must be prime */
56#define AHASH(a) &ahash_tbl[(a)%AHASH_LEN]
57struct interface *ahash_tbl[AHASH_LEN];
58
59#define BHASH_LEN 211			/* must be prime */
60#define BHASH(a) &bhash_tbl[(a)%BHASH_LEN]
61struct interface *bhash_tbl[BHASH_LEN];
62
63struct interface *remote_if;		/* remote interfaces */
64
65/* hash for physical interface names.
66 * Assume there are never more 100 or 200 real interfaces, and that
67 * aliases are put on the end of the hash chains.
68 */
69#define NHASH_LEN 97
70struct interface *nhash_tbl[NHASH_LEN];
71
72int	tot_interfaces;			/* # of remote and local interfaces */
73int	rip_interfaces;			/* # of interfaces doing RIP */
74int	foundloopback;			/* valid flag for loopaddr */
75naddr	loopaddr;			/* our address on loopback */
76struct	rt_spare loop_rts;
77
78struct timeval ifinit_timer;
79static struct timeval last_ifinit;
80#define IF_RESCAN_DELAY() (last_ifinit.tv_sec == now.tv_sec		\
81			   && last_ifinit.tv_usec == now.tv_usec	\
82			   && timercmp(&ifinit_timer, &now, >))
83
84int	have_ripv1_out;			/* have a RIPv1 interface */
85int	have_ripv1_in;
86
87
88static struct interface**
89nhash(char *p)
90{
91	u_int i;
92
93	for (i = 0; *p != '\0'; p++) {
94		i = ((i<<1) & 0x7fffffff) | ((i>>31) & 1);
95		i ^= *p;
96	}
97	return &nhash_tbl[i % NHASH_LEN];
98}
99
100
101/* Link a new interface into the lists and hash tables.
102 */
103void
104if_link(struct interface *ifp)
105{
106	struct interface **hifp;
107
108	ifp->int_prev = &ifnet;
109	ifp->int_next = ifnet;
110	if (ifnet != 0)
111		ifnet->int_prev = &ifp->int_next;
112	ifnet = ifp;
113
114	hifp = AHASH(ifp->int_addr);
115	ifp->int_ahash_prev = hifp;
116	if ((ifp->int_ahash = *hifp) != 0)
117		(*hifp)->int_ahash_prev = &ifp->int_ahash;
118	*hifp = ifp;
119
120	if (ifp->int_if_flags & IFF_BROADCAST) {
121		hifp = BHASH(ifp->int_brdaddr);
122		ifp->int_bhash_prev = hifp;
123		if ((ifp->int_bhash = *hifp) != 0)
124			(*hifp)->int_bhash_prev = &ifp->int_bhash;
125		*hifp = ifp;
126	}
127
128	if (ifp->int_state & IS_REMOTE) {
129		ifp->int_rlink_prev = &remote_if;
130		ifp->int_rlink = remote_if;
131		if (remote_if != 0)
132			remote_if->int_rlink_prev = &ifp->int_rlink;
133		remote_if = ifp;
134	}
135
136	hifp = nhash(ifp->int_name);
137	if (ifp->int_state & IS_ALIAS) {
138		/* put aliases on the end of the hash chain */
139		while (*hifp != 0)
140			hifp = &(*hifp)->int_nhash;
141	}
142	ifp->int_nhash_prev = hifp;
143	if ((ifp->int_nhash = *hifp) != 0)
144		(*hifp)->int_nhash_prev = &ifp->int_nhash;
145	*hifp = ifp;
146}
147
148
149/* Find the interface with an address
150 */
151struct interface *
152ifwithaddr(naddr addr,
153	   int	bcast,			/* notice IFF_BROADCAST address */
154	   int	remote)			/* include IS_REMOTE interfaces */
155{
156	struct interface *ifp, *possible = 0;
157
158	remote = (remote == 0) ? IS_REMOTE : 0;
159
160	for (ifp = *AHASH(addr); ifp; ifp = ifp->int_ahash) {
161		if (ifp->int_addr != addr)
162			continue;
163		if ((ifp->int_state & remote) != 0)
164			continue;
165		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
166			return ifp;
167		possible = ifp;
168	}
169
170	if (possible || !bcast)
171		return possible;
172
173	for (ifp = *BHASH(addr); ifp; ifp = ifp->int_bhash) {
174		if (ifp->int_brdaddr != addr)
175			continue;
176		if ((ifp->int_state & remote) != 0)
177			continue;
178		if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
179			return ifp;
180		possible = ifp;
181	}
182
183	return possible;
184}
185
186
187/* find the interface with a name
188 */
189struct interface *
190ifwithname(char *name,			/* "ec0" or whatever */
191	   naddr addr)			/* 0 or network address */
192{
193	struct interface *ifp;
194
195	for (;;) {
196		for (ifp = *nhash(name); ifp != 0; ifp = ifp->int_nhash) {
197			/* If the network address is not specified,
198			 * ignore any alias interfaces.  Otherwise, look
199			 * for the interface with the target name and address.
200			 */
201			if (!strcmp(ifp->int_name, name)
202			    && ((addr == 0 && !(ifp->int_state & IS_ALIAS))
203				|| (ifp->int_addr == addr)))
204				return ifp;
205		}
206
207		/* If there is no known interface, maybe there is a
208		 * new interface.  So just once look for new interfaces.
209		 */
210		if (IF_RESCAN_DELAY())
211			return 0;
212		ifinit();
213	}
214}
215
216
217struct interface *
218ifwithindex(u_short ifindex,
219	    int rescan_ok)
220{
221	struct interface *ifp;
222
223	for (;;) {
224		for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
225			if (ifp->int_index == ifindex)
226				return ifp;
227		}
228
229		/* If there is no known interface, maybe there is a
230		 * new interface.  So just once look for new interfaces.
231		 */
232		if (!rescan_ok
233		    || IF_RESCAN_DELAY())
234			return 0;
235		ifinit();
236	}
237}
238
239
240/* Find an interface from which the specified address
241 * should have come from.  Used for figuring out which
242 * interface a packet came in on.
243 */
244struct interface *
245iflookup(naddr addr)
246{
247	struct interface *ifp, *maybe;
248	int once = 0;
249
250	maybe = 0;
251	for (;;) {
252		for (ifp = ifnet; ifp; ifp = ifp->int_next) {
253			if (ifp->int_if_flags & IFF_POINTOPOINT) {
254				/* finished with a match */
255				if (ifp->int_dstaddr == addr)
256					return ifp;
257
258			} else {
259				/* finished with an exact match */
260				if (ifp->int_addr == addr)
261					return ifp;
262
263				/* Look for the longest approximate match.
264				 */
265				if (on_net(addr, ifp->int_net, ifp->int_mask)
266				    && (maybe == 0
267					|| ifp->int_mask > maybe->int_mask))
268					maybe = ifp;
269			}
270		}
271
272		if (maybe != 0 || once || IF_RESCAN_DELAY())
273			return maybe;
274		once = 1;
275
276		/* If there is no known interface, maybe there is a
277		 * new interface.  So just once look for new interfaces.
278		 */
279		ifinit();
280	}
281}
282
283
284/* Return the classical netmask for an IP address.
285 */
286naddr					/* host byte order */
287std_mask(naddr addr)			/* network byte order */
288{
289	addr = ntohl(addr);		/* was a host, not a network */
290
291	if (addr == 0)			/* default route has mask 0 */
292		return 0;
293	if (IN_CLASSA(addr))
294		return IN_CLASSA_NET;
295	if (IN_CLASSB(addr))
296		return IN_CLASSB_NET;
297	return IN_CLASSC_NET;
298}
299
300
301/* Find the netmask that would be inferred by RIPv1 listeners
302 *	on the given interface for a given network.
303 *	If no interface is specified, look for the best fitting	interface.
304 */
305naddr
306ripv1_mask_net(naddr addr,		/* in network byte order */
307	       struct interface *ifp)	/* as seen on this interface */
308{
309	struct r1net *r1p;
310	naddr mask = 0;
311
312	if (addr == 0)			/* default always has 0 mask */
313		return mask;
314
315	if (ifp != 0 && ifp->int_ripv1_mask != HOST_MASK) {
316		/* If the target network is that of the associated interface
317		 * on which it arrived, then use the netmask of the interface.
318		 */
319		if (on_net(addr, ifp->int_net, ifp->int_std_mask))
320			mask = ifp->int_ripv1_mask;
321
322	} else {
323		/* Examine all interfaces, and if it the target seems
324		 * to have the same network number of an interface, use the
325		 * netmask of that interface.  If there is more than one
326		 * such interface, prefer the interface with the longest
327		 * match.
328		 */
329		for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
330			if (on_net(addr, ifp->int_std_net, ifp->int_std_mask)
331			    && ifp->int_ripv1_mask > mask
332			    && ifp->int_ripv1_mask != HOST_MASK)
333				mask = ifp->int_ripv1_mask;
334		}
335
336	}
337
338	/* check special definitions */
339	if (mask == 0) {
340		for (r1p = r1nets; r1p != 0; r1p = r1p->r1net_next) {
341			if (on_net(addr, r1p->r1net_net, r1p->r1net_match)
342			    && r1p->r1net_mask > mask)
343				mask = r1p->r1net_mask;
344		}
345
346		/* Otherwise, make the classic A/B/C guess.
347		 */
348		if (mask == 0)
349			mask = std_mask(addr);
350	}
351
352	return mask;
353}
354
355
356naddr
357ripv1_mask_host(naddr addr,		/* in network byte order */
358		struct interface *ifp)	/* as seen on this interface */
359{
360	naddr mask = ripv1_mask_net(addr, ifp);
361
362
363	/* If the computed netmask does not mask the address,
364	 * then assume it is a host address
365	 */
366	if ((ntohl(addr) & ~mask) != 0)
367		mask = HOST_MASK;
368	return mask;
369}
370
371
372/* See if a IP address looks reasonable as a destination
373 */
374int					/* 0=bad */
375check_dst(naddr addr)
376{
377	addr = ntohl(addr);
378
379	if (IN_CLASSA(addr)) {
380		if (addr == 0)
381			return 1;	/* default */
382
383		addr >>= IN_CLASSA_NSHIFT;
384		return (addr != 0 && addr != IN_LOOPBACKNET);
385	}
386
387	return (IN_CLASSB(addr) || IN_CLASSC(addr));
388}
389
390
391/* See a new interface duplicates an existing interface.
392 */
393struct interface *
394check_dup(naddr addr,			/* IP address, so network byte order */
395	  naddr dstaddr,		/* ditto */
396	  naddr mask,			/* mask, so host byte order */
397	  int if_flags)
398{
399	struct interface *ifp;
400
401	for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
402		if (ifp->int_mask != mask)
403			continue;
404
405		if (!iff_up(ifp->int_if_flags))
406			continue;
407
408		/* The local address can only be shared with a point-to-point
409		 * link.
410		 */
411		if ((!(ifp->int_state & IS_REMOTE) || !(if_flags & IS_REMOTE))
412		    && ifp->int_addr == addr
413		    && (((if_flags|ifp->int_if_flags) & IFF_POINTOPOINT) == 0))
414			return ifp;
415
416		if (on_net(ifp->int_dstaddr, ntohl(dstaddr),mask))
417			return ifp;
418	}
419	return 0;
420}
421
422
423/* See that a remote gateway is reachable.
424 *	Note that the answer can change as real interfaces come and go.
425 */
426int					/* 0=bad */
427check_remote(struct interface *ifp)
428{
429	struct rt_entry *rt;
430
431	/* do not worry about other kinds */
432	if (!(ifp->int_state & IS_REMOTE))
433	    return 1;
434
435	rt = rtfind(ifp->int_addr);
436	if (rt != 0
437	    && rt->rt_ifp != 0
438	    &&on_net(ifp->int_addr,
439		     rt->rt_ifp->int_net, rt->rt_ifp->int_mask))
440		return 1;
441
442	/* the gateway cannot be reached directly from one of our
443	 * interfaces
444	 */
445	if (!(ifp->int_state & IS_BROKE)) {
446		msglog("unreachable gateway %s in "_PATH_GATEWAYS,
447		       naddr_ntoa(ifp->int_addr));
448		if_bad(ifp);
449	}
450	return 0;
451}
452
453
454/* Delete an interface.
455 */
456static void
457ifdel(struct interface *ifp)
458{
459	struct ip_mreq m;
460	struct interface *ifp1;
461
462
463	trace_if("Del", ifp);
464
465	ifp->int_state |= IS_BROKE;
466
467	/* unlink the interface
468	 */
469	*ifp->int_prev = ifp->int_next;
470	if (ifp->int_next != 0)
471		ifp->int_next->int_prev = ifp->int_prev;
472	*ifp->int_ahash_prev = ifp->int_ahash;
473	if (ifp->int_ahash != 0)
474		ifp->int_ahash->int_ahash_prev = ifp->int_ahash_prev;
475	*ifp->int_nhash_prev = ifp->int_nhash;
476	if (ifp->int_nhash != 0)
477		ifp->int_nhash->int_nhash_prev = ifp->int_nhash_prev;
478	if (ifp->int_if_flags & IFF_BROADCAST) {
479		*ifp->int_bhash_prev = ifp->int_bhash;
480		if (ifp->int_bhash != 0)
481			ifp->int_bhash->int_bhash_prev = ifp->int_bhash_prev;
482	}
483	if (ifp->int_state & IS_REMOTE) {
484		*ifp->int_rlink_prev = ifp->int_rlink;
485		if (ifp->int_rlink != 0)
486			ifp->int_rlink->int_rlink_prev = ifp->int_rlink_prev;
487	}
488
489	if (!(ifp->int_state & IS_ALIAS)) {
490		/* delete aliases when the main interface dies
491		 */
492		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
493			if (ifp1 != ifp
494			    && !strcmp(ifp->int_name, ifp1->int_name))
495				ifdel(ifp1);
496		}
497
498		if ((ifp->int_if_flags & IFF_MULTICAST)
499#ifdef MCAST_PPP_BUG
500		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
501#endif
502		    && rip_sock >= 0) {
503			m.imr_multiaddr.s_addr = htonl(INADDR_RIP_GROUP);
504#ifdef MCAST_IFINDEX
505			m.imr_interface.s_addr = htonl(ifp->int_index);
506#else
507			m.imr_interface.s_addr = ((ifp->int_if_flags
508						   & IFF_POINTOPOINT)
509						  ? ifp->int_dstaddr
510						  : ifp->int_addr);
511#endif
512			if (setsockopt(rip_sock,IPPROTO_IP,IP_DROP_MEMBERSHIP,
513				       &m, sizeof(m)) < 0
514			    && errno != EADDRNOTAVAIL
515			    && !TRACEACTIONS)
516				LOGERR("setsockopt(IP_DROP_MEMBERSHIP RIP)");
517			if (rip_sock_mcast == ifp)
518				rip_sock_mcast = 0;
519		}
520		if (ifp->int_rip_sock >= 0) {
521			(void)close(ifp->int_rip_sock);
522			ifp->int_rip_sock = -1;
523			fix_select();
524		}
525
526		tot_interfaces--;
527		if (!IS_RIP_OFF(ifp->int_state))
528			rip_interfaces--;
529
530		/* Zap all routes associated with this interface.
531		 * Assume routes just using gateways beyond this interface
532		 * will timeout naturally, and have probably already died.
533		 */
534		(void)rn_walktree(rhead, walk_bad, 0);
535
536		set_rdisc_mg(ifp, 0);
537		if_bad_rdisc(ifp);
538	}
539
540	free(ifp);
541}
542
543
544/* Mark an interface ill.
545 */
546void
547if_sick(struct interface *ifp)
548{
549	if (0 == (ifp->int_state & (IS_SICK | IS_BROKE))) {
550		ifp->int_state |= IS_SICK;
551		ifp->int_act_time = NEVER;
552		trace_if("Chg", ifp);
553
554		LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
555	}
556}
557
558
559/* Mark an interface dead.
560 */
561void
562if_bad(struct interface *ifp)
563{
564	struct interface *ifp1;
565
566
567	if (ifp->int_state & IS_BROKE)
568		return;
569
570	LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
571
572	ifp->int_state |= (IS_BROKE | IS_SICK);
573	ifp->int_act_time = NEVER;
574	ifp->int_query_time = NEVER;
575	ifp->int_data.ts = now.tv_sec;
576
577	trace_if("Chg", ifp);
578
579	if (!(ifp->int_state & IS_ALIAS)) {
580		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
581			if (ifp1 != ifp
582			    && !strcmp(ifp->int_name, ifp1->int_name))
583				if_bad(ifp1);
584		}
585		(void)rn_walktree(rhead, walk_bad, 0);
586		if_bad_rdisc(ifp);
587	}
588}
589
590
591/* Mark an interface alive
592 */
593int					/* 1=it was dead */
594if_ok(struct interface *ifp,
595      const char *type)
596{
597	struct interface *ifp1;
598
599
600	if (!(ifp->int_state & IS_BROKE)) {
601		if (ifp->int_state & IS_SICK) {
602			trace_act("%sinterface %s to %s working better",
603				  type,
604				  ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
605			ifp->int_state &= ~IS_SICK;
606		}
607		return 0;
608	}
609
610	msglog("%sinterface %s to %s restored",
611	       type, ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
612	ifp->int_state &= ~(IS_BROKE | IS_SICK);
613	ifp->int_data.ts = 0;
614
615	if (!(ifp->int_state & IS_ALIAS)) {
616		for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
617			if (ifp1 != ifp
618			    && !strcmp(ifp->int_name, ifp1->int_name))
619				if_ok(ifp1, type);
620		}
621		if_ok_rdisc(ifp);
622	}
623
624	if (ifp->int_state & IS_REMOTE) {
625		if (!addrouteforif(ifp))
626			return 0;
627	}
628	return 1;
629}
630
631
632/* disassemble routing message
633 */
634void
635rt_xaddrs(struct rt_addrinfo *info,
636	  struct sockaddr *sa,
637	  struct sockaddr *lim,
638	  int addrs)
639{
640	int i;
641#ifdef _HAVE_SA_LEN
642	static struct sockaddr sa_zero;
643#endif
644#if defined(__NetBSD__) && defined(RT_ROUNDUP)
645#define ROUNDUP(a) RT_ROUNDUP(a)
646#else
647#ifdef sgi
648#define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) \
649		    : sizeof(__uint64_t))
650#else
651#define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) \
652		    : sizeof(long))
653#endif
654#endif /* defined(__NetBSD__) && defined(RT_ROUNDUP) */
655
656
657	memset(info, 0, sizeof(*info));
658	info->rti_addrs = addrs;
659	for (i = 0; i < RTAX_MAX && sa < lim; i++) {
660		if ((addrs & (1 << i)) == 0)
661			continue;
662#ifdef _HAVE_SA_LEN
663		info->rti_info[i] = (sa->sa_len != 0) ? sa : &sa_zero;
664		sa = (struct sockaddr *)((char*)(sa)
665					 + ROUNDUP(sa->sa_len));
666#else
667		info->rti_info[i] = sa;
668		sa = (struct sockaddr *)((char*)(sa)
669					 + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
670#endif
671	}
672}
673
674
675/* Find the network interfaces which have configured themselves.
676 *	This must be done regularly, if only for extra addresses
677 *	that come and go on interfaces.
678 */
679void
680ifinit(void)
681{
682	static char *sysctl_buf;
683	static size_t sysctl_buf_size = 0;
684	uint complaints = 0;
685	static u_int prev_complaints = 0;
686#	define COMP_NOT_INET	0x001
687#	define COMP_NOADDR	0x002
688#	define COMP_BADADDR	0x004
689#	define COMP_NODST	0x008
690#	define COMP_NOBADR	0x010
691#	define COMP_NOMASK	0x020
692#	define COMP_DUP		0x040
693#	define COMP_BAD_METRIC	0x080
694#	define COMP_NETMASK	0x100
695
696	struct interface ifs, ifs0, *ifp, *ifp1;
697	struct rt_entry *rt;
698	size_t needed;
699	int mib[6];
700	struct if_msghdr ifm;
701	struct ifa_msghdr *ifam, *ifam_lim, *ifam2;
702	int in, ierr, out, oerr;
703	struct intnet *intnetp;
704	struct rt_addrinfo info;
705#ifdef SIOCGIFMETRIC
706	struct ifreq ifr;
707#endif
708
709
710	last_ifinit = now;
711	ifinit_timer.tv_sec = now.tv_sec + (supplier
712					    ? CHECK_ACT_INTERVAL
713					    : CHECK_QUIET_INTERVAL);
714
715	/* mark all interfaces so we can get rid of those that disappear */
716	for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next)
717		ifp->int_state &= ~(IS_CHECKED | IS_DUP);
718
719	/* Fetch the interface list, without too many system calls
720	 * since we do it repeatedly.
721	 */
722	mib[0] = CTL_NET;
723	mib[1] = PF_ROUTE;
724	mib[2] = 0;
725	mib[3] = AF_INET;
726	mib[4] = NET_RT_IFLIST;
727	mib[5] = 0;
728	for (;;) {
729		if ((needed = sysctl_buf_size) != 0) {
730			if (sysctl(mib, 6, sysctl_buf,&needed, 0, 0) >= 0)
731				break;
732			/* retry if the table grew */
733			if (errno != ENOMEM && errno != EFAULT)
734				BADERR(1, "ifinit: sysctl(RT_IFLIST)");
735			free(sysctl_buf);
736			needed = 0;
737		}
738		if (sysctl(mib, 6, 0, &needed, 0, 0) < 0)
739			BADERR(1,"ifinit: sysctl(RT_IFLIST) estimate");
740		sysctl_buf = rtmalloc(sysctl_buf_size = needed,
741				      "ifinit sysctl");
742	}
743
744	ifam_lim = (struct ifa_msghdr *)(sysctl_buf + needed);
745	for (ifam = (struct ifa_msghdr *)sysctl_buf;
746	     ifam < ifam_lim;
747	     ifam = ifam2) {
748
749		ifam2 = (struct ifa_msghdr*)((char*)ifam + ifam->ifam_msglen);
750
751#ifdef RTM_OIFINFO
752		if (ifam->ifam_type == RTM_OIFINFO)
753			continue;	/* just ignore compat message */
754#endif
755		if (ifam->ifam_type == RTM_IFINFO) {
756			const struct sockaddr_dl *sdl;
757
758			memcpy(&ifm, ifam, sizeof ifm);
759			/* make prototype structure for the IP aliases
760			 */
761			memset(&ifs0, 0, sizeof(ifs0));
762			ifs0.int_rip_sock = -1;
763			ifs0.int_index = ifm.ifm_index;
764			ifs0.int_if_flags = ifm.ifm_flags;
765			ifs0.int_state = IS_CHECKED;
766			ifs0.int_query_time = NEVER;
767			ifs0.int_act_time = now.tv_sec;
768			ifs0.int_data.ts = now.tv_sec;
769			ifs0.int_data.ipackets = ifm.ifm_data.ifi_ipackets;
770			ifs0.int_data.ierrors = ifm.ifm_data.ifi_ierrors;
771			ifs0.int_data.opackets = ifm.ifm_data.ifi_opackets;
772			ifs0.int_data.oerrors = ifm.ifm_data.ifi_oerrors;
773#ifdef sgi
774			ifs0.int_data.odrops = ifm.ifm_data.ifi_odrops;
775#endif
776			sdl = (const struct sockaddr_dl *)
777				((struct if_msghdr *)ifam + 1);
778			/* NUL-termination by memset, above. */
779			memcpy(ifs0.int_name, sdl->sdl_data,
780				MIN(sizeof(ifs0.int_name) - 1, sdl->sdl_nlen));
781			continue;
782		}
783		if (ifam->ifam_type != RTM_NEWADDR) {
784			logbad(1,"ifinit: out of sync");
785			continue;
786		}
787		rt_xaddrs(&info, (struct sockaddr *)(ifam+1),
788			  (struct sockaddr *)ifam2,
789			  ifam->ifam_addrs);
790
791		/* Prepare for the next address of this interface, which
792		 * will be an alias.
793		 * Do not output RIP or Router-Discovery packets via aliases.
794		 */
795		memcpy(&ifs, &ifs0, sizeof(ifs));
796		ifs0.int_state |= (IS_ALIAS | IS_NO_RIP_OUT | IS_NO_RDISC);
797
798		if (INFO_IFA(&info) == 0) {
799			if (iff_up(ifs.int_if_flags)) {
800				if (!(prev_complaints & COMP_NOADDR))
801					msglog("%s has no address",
802					       ifs.int_name);
803				complaints |= COMP_NOADDR;
804			}
805			continue;
806		}
807		if (INFO_IFA(&info)->sa_family != AF_INET) {
808			if (iff_up(ifs.int_if_flags)) {
809				if (!(prev_complaints & COMP_NOT_INET))
810					trace_act("%s: not AF_INET",
811						  ifs.int_name);
812				complaints |= COMP_NOT_INET;
813			}
814			continue;
815		}
816
817		ifs.int_addr = S_ADDR(INFO_IFA(&info));
818
819		if (ntohl(ifs.int_addr)>>24 == 0
820		    || ntohl(ifs.int_addr)>>24 == 0xff) {
821			if (iff_up(ifs.int_if_flags)) {
822				if (!(prev_complaints & COMP_BADADDR))
823					msglog("%s has a bad address",
824					       ifs.int_name);
825				complaints |= COMP_BADADDR;
826			}
827			continue;
828		}
829
830		if (ifs.int_if_flags & IFF_LOOPBACK) {
831			ifs.int_state |= IS_PASSIVE | IS_NO_RIP | IS_NO_RDISC;
832			ifs.int_dstaddr = ifs.int_addr;
833			ifs.int_mask = HOST_MASK;
834			ifs.int_ripv1_mask = HOST_MASK;
835			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
836			ifs.int_net = ntohl(ifs.int_dstaddr);
837			if (!foundloopback) {
838				foundloopback = 1;
839				loopaddr = ifs.int_addr;
840				loop_rts.rts_gate = loopaddr;
841				loop_rts.rts_router = loopaddr;
842			}
843
844		} else if (ifs.int_if_flags & IFF_POINTOPOINT) {
845			if (INFO_BRD(&info) == 0
846			    || INFO_BRD(&info)->sa_family != AF_INET) {
847				if (iff_up(ifs.int_if_flags)) {
848					if (!(prev_complaints & COMP_NODST))
849						msglog("%s has a bad"
850						       " destination address",
851						       ifs.int_name);
852					complaints |= COMP_NODST;
853				}
854				continue;
855			}
856			ifs.int_dstaddr = S_ADDR(INFO_BRD(&info));
857			if (ntohl(ifs.int_dstaddr)>>24 == 0
858			    || ntohl(ifs.int_dstaddr)>>24 == 0xff) {
859				if (iff_up(ifs.int_if_flags)) {
860					if (!(prev_complaints & COMP_NODST))
861						msglog("%s has a bad"
862						       " destination address",
863						       ifs.int_name);
864					complaints |= COMP_NODST;
865				}
866				continue;
867			}
868			ifs.int_mask = HOST_MASK;
869			ifs.int_ripv1_mask = ntohl(S_ADDR(INFO_MASK(&info)));
870			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
871			ifs.int_net = ntohl(ifs.int_dstaddr);
872
873		}  else {
874			if (INFO_MASK(&info) == 0) {
875				if (iff_up(ifs.int_if_flags)) {
876					if (!(prev_complaints & COMP_NOMASK))
877						msglog("%s has no netmask",
878						       ifs.int_name);
879					complaints |= COMP_NOMASK;
880				}
881				continue;
882			}
883			ifs.int_dstaddr = ifs.int_addr;
884			ifs.int_mask = ntohl(S_ADDR(INFO_MASK(&info)));
885			ifs.int_ripv1_mask = ifs.int_mask;
886			ifs.int_std_mask = std_mask(ifs.int_addr);
887			ifs.int_net = ntohl(ifs.int_addr) & ifs.int_mask;
888			if (ifs.int_mask != ifs.int_std_mask)
889				ifs.int_state |= IS_SUBNET;
890
891			if (ifs.int_if_flags & IFF_BROADCAST) {
892				if (INFO_BRD(&info) == 0) {
893					if (iff_up(ifs.int_if_flags)) {
894					    if (!(prev_complaints
895						  & COMP_NOBADR))
896						msglog("%s has"
897						       "no broadcast address",
898						       ifs.int_name);
899					    complaints |= COMP_NOBADR;
900					}
901					continue;
902				}
903				ifs.int_brdaddr = S_ADDR(INFO_BRD(&info));
904			}
905		}
906		ifs.int_std_net = ifs.int_net & ifs.int_std_mask;
907		ifs.int_std_addr = htonl(ifs.int_std_net);
908
909		/* Use a minimum metric of one.  Treat the interface metric
910		 * (default 0) as an increment to the hop count of one.
911		 *
912		 * The metric obtained from the routing socket dump of
913		 * interface addresses is wrong.  It is not set by the
914		 * SIOCSIFMETRIC ioctl.
915		 */
916#ifdef SIOCGIFMETRIC
917		strncpy(ifr.ifr_name, ifs.int_name, sizeof(ifr.ifr_name));
918		if (ioctl(rt_sock, SIOCGIFMETRIC, &ifr) < 0) {
919			DBGERR(1, "ioctl(SIOCGIFMETRIC)");
920			ifs.int_metric = 0;
921		} else {
922			ifs.int_metric = ifr.ifr_metric;
923		}
924#else
925		ifs.int_metric = ifam->ifam_metric;
926#endif
927		if (ifs.int_metric > HOPCNT_INFINITY) {
928			ifs.int_metric = 0;
929			if (!(prev_complaints & COMP_BAD_METRIC)
930			    && iff_up(ifs.int_if_flags)) {
931				complaints |= COMP_BAD_METRIC;
932				msglog("%s has a metric of %d",
933				       ifs.int_name, ifs.int_metric);
934			}
935		}
936
937		/* See if this is a familiar interface.
938		 * If so, stop worrying about it if it is the same.
939		 * Start it over if it now is to somewhere else, as happens
940		 * frequently with PPP and SLIP.
941		 */
942		ifp = ifwithname(ifs.int_name, ((ifs.int_state & IS_ALIAS)
943						? ifs.int_addr
944						: 0));
945		if (ifp != 0) {
946			ifp->int_state |= IS_CHECKED;
947
948			if (0 != ((ifp->int_if_flags ^ ifs.int_if_flags)
949				  & (IFF_BROADCAST
950				     | IFF_LOOPBACK
951				     | IFF_POINTOPOINT
952				     | IFF_MULTICAST))
953			    || 0 != ((ifp->int_state ^ ifs.int_state)
954				     & IS_ALIAS)
955			    || ifp->int_addr != ifs.int_addr
956			    || ifp->int_brdaddr != ifs.int_brdaddr
957			    || ifp->int_dstaddr != ifs.int_dstaddr
958			    || ifp->int_mask != ifs.int_mask
959			    || ifp->int_metric != ifs.int_metric) {
960				/* Forget old information about
961				 * a changed interface.
962				 */
963				trace_act("interface %s has changed",
964					  ifp->int_name);
965				ifdel(ifp);
966				ifp = 0;
967			}
968		}
969
970		if (ifp != 0) {
971			/* The primary representative of an alias worries
972			 * about how things are working.
973			 */
974			if (ifp->int_state & IS_ALIAS)
975				continue;
976
977			/* note interfaces that have been turned off
978			 */
979			if (!iff_up(ifs.int_if_flags)) {
980				if (iff_up(ifp->int_if_flags)) {
981					msglog("interface %s to %s turned off",
982					       ifp->int_name,
983					       naddr_ntoa(ifp->int_dstaddr));
984					if_bad(ifp);
985					ifp->int_if_flags &= ~IFF_UP;
986				} else if (now.tv_sec>(ifp->int_data.ts
987						       + CHECK_BAD_INTERVAL)) {
988					trace_act("interface %s has been off"
989						  " %lld seconds; forget it",
990						  ifp->int_name,
991						  (long long)now.tv_sec -
992						  ifp->int_data.ts);
993					ifdel(ifp);
994					ifp = 0;
995				}
996				continue;
997			}
998			/* or that were off and are now ok */
999			if (!iff_up(ifp->int_if_flags)) {
1000				ifp->int_if_flags |= IFF_UP;
1001				(void)if_ok(ifp, "");
1002			}
1003
1004			/* If it has been long enough,
1005			 * see if the interface is broken.
1006			 */
1007			if (now.tv_sec < ifp->int_data.ts+CHECK_BAD_INTERVAL)
1008				continue;
1009
1010			in = ifs.int_data.ipackets - ifp->int_data.ipackets;
1011			ierr = ifs.int_data.ierrors - ifp->int_data.ierrors;
1012			out = ifs.int_data.opackets - ifp->int_data.opackets;
1013			oerr = ifs.int_data.oerrors - ifp->int_data.oerrors;
1014#ifdef sgi
1015			/* Through at least IRIX 6.2, PPP and SLIP
1016			 * count packets dropped by the filters.
1017			 * But FDDI rings stuck non-operational count
1018			 * dropped packets as they wait for improvement.
1019			 */
1020			if (!(ifp->int_if_flags & IFF_POINTOPOINT))
1021				oerr += (ifs.int_data.odrops
1022					 - ifp->int_data.odrops);
1023#endif
1024			/* If the interface just awoke, restart the counters.
1025			 */
1026			if (ifp->int_data.ts == 0) {
1027				ifp->int_data = ifs.int_data;
1028				continue;
1029			}
1030			ifp->int_data = ifs.int_data;
1031
1032			/* Withhold judgment when the short error
1033			 * counters wrap or the interface is reset.
1034			 */
1035			if (ierr < 0 || in < 0 || oerr < 0 || out < 0) {
1036				LIM_SEC(ifinit_timer,
1037					now.tv_sec+CHECK_BAD_INTERVAL);
1038				continue;
1039			}
1040
1041			/* Withhold judgement when there is no traffic
1042			 */
1043			if (in == 0 && out == 0 && ierr == 0 && oerr == 0)
1044				continue;
1045
1046			/* It is bad if input or output is not working.
1047			 * Require presistent problems before marking it dead.
1048			 */
1049			if ((in <= ierr && ierr > 0)
1050			    || (out <= oerr && oerr > 0)) {
1051				if (!(ifp->int_state & IS_SICK)) {
1052					trace_act("interface %s to %s"
1053						  " sick: in=%d ierr=%d"
1054						  " out=%d oerr=%d",
1055						  ifp->int_name,
1056						  naddr_ntoa(ifp->int_dstaddr),
1057						  in, ierr, out, oerr);
1058					if_sick(ifp);
1059					continue;
1060				}
1061				if (!(ifp->int_state & IS_BROKE)) {
1062					msglog("interface %s to %s broken:"
1063					       " in=%d ierr=%d out=%d oerr=%d",
1064					       ifp->int_name,
1065					       naddr_ntoa(ifp->int_dstaddr),
1066					       in, ierr, out, oerr);
1067					if_bad(ifp);
1068				}
1069				continue;
1070			}
1071
1072			/* otherwise, it is active and healthy
1073			 */
1074			ifp->int_act_time = now.tv_sec;
1075			(void)if_ok(ifp, "");
1076			continue;
1077		}
1078
1079		/* This is a new interface.
1080		 * If it is dead, forget it.
1081		 */
1082		if (!iff_up(ifs.int_if_flags))
1083			continue;
1084
1085		/* If it duplicates an existing interface,
1086		 * complain about it, mark the other one
1087		 * duplicated, and forget this one.
1088		 */
1089		ifp = check_dup(ifs.int_addr,ifs.int_dstaddr,ifs.int_mask,
1090				ifs.int_if_flags);
1091		if (ifp != 0) {
1092			/* Ignore duplicates of itself, caused by having
1093			 * IP aliases on the same network.
1094			 */
1095			if (!strcmp(ifp->int_name, ifs.int_name))
1096				continue;
1097
1098			if (!(prev_complaints & COMP_DUP)) {
1099				complaints |= COMP_DUP;
1100				msglog("%s (%s%s%s) is duplicated by"
1101				       " %s (%s%s%s)",
1102				       ifs.int_name,
1103				       addrname(ifs.int_addr,ifs.int_mask,1),
1104				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1105					? "-->" : ""),
1106				       ((ifs.int_if_flags & IFF_POINTOPOINT)
1107					? naddr_ntoa(ifs.int_dstaddr) : ""),
1108				       ifp->int_name,
1109				       addrname(ifp->int_addr,ifp->int_mask,1),
1110				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1111					? "-->" : ""),
1112				       ((ifp->int_if_flags & IFF_POINTOPOINT)
1113					? naddr_ntoa(ifp->int_dstaddr) : ""));
1114			}
1115			ifp->int_state |= IS_DUP;
1116			continue;
1117		}
1118
1119		if (0 == (ifs.int_if_flags & (IFF_POINTOPOINT | IFF_BROADCAST))
1120		    && !(ifs.int_state & IS_PASSIVE)) {
1121			trace_act("%s is neither broadcast, point-to-point,"
1122				  " nor loopback",
1123				  ifs.int_name);
1124			if (!(ifs.int_state & IFF_MULTICAST))
1125				ifs.int_state |= IS_NO_RDISC;
1126		}
1127
1128
1129		/* It is new and ok.   Add it to the list of interfaces
1130		 */
1131		ifp = (struct interface *)rtmalloc(sizeof(*ifp), "ifinit ifp");
1132		memcpy(ifp, &ifs, sizeof(*ifp));
1133		get_parms(ifp);
1134		if_link(ifp);
1135		trace_if("Add", ifp);
1136
1137		/* Notice likely bad netmask.
1138		 */
1139		if (!(prev_complaints & COMP_NETMASK)
1140		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
1141		    && ifp->int_addr != RIP_DEFAULT) {
1142			for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
1143				if (ifp1->int_mask == ifp->int_mask)
1144					continue;
1145				if (ifp1->int_if_flags & IFF_POINTOPOINT)
1146					continue;
1147				if (ifp1->int_dstaddr == RIP_DEFAULT)
1148					continue;
1149				/* ignore aliases on the right network */
1150				if (!strcmp(ifp->int_name, ifp1->int_name))
1151					continue;
1152				if (on_net(ifp->int_dstaddr,
1153					   ifp1->int_net, ifp1->int_mask)
1154				    || on_net(ifp1->int_dstaddr,
1155					      ifp->int_net, ifp->int_mask)) {
1156					msglog("possible netmask problem"
1157					       " between %s:%s and %s:%s",
1158					       ifp->int_name,
1159					       addrname(htonl(ifp->int_net),
1160							ifp->int_mask, 1),
1161					       ifp1->int_name,
1162					       addrname(htonl(ifp1->int_net),
1163							ifp1->int_mask, 1));
1164					complaints |= COMP_NETMASK;
1165				}
1166			}
1167		}
1168
1169		if (!(ifp->int_state & IS_ALIAS)) {
1170			/* Count the # of directly connected networks.
1171			 */
1172			if (!(ifp->int_if_flags & IFF_LOOPBACK))
1173				tot_interfaces++;
1174			if (!IS_RIP_OFF(ifp->int_state))
1175				rip_interfaces++;
1176
1177			/* turn on router discovery and RIP If needed */
1178			if_ok_rdisc(ifp);
1179			rip_on(ifp);
1180		}
1181	}
1182
1183	/* If we are multi-homed and have at least two interfaces
1184	 * listening to RIP, then output by default.
1185	 */
1186	if (!supplier_set && rip_interfaces > 1)
1187		set_supplier();
1188
1189	/* If we are multi-homed, optionally advertise a route to
1190	 * our main address.
1191	 */
1192	if ((advertise_mhome && ifp)
1193	    || (tot_interfaces > 1
1194		&& mhome
1195		&& (ifp = ifwithaddr(myaddr, 0, 0)) != 0
1196		&& foundloopback)) {
1197		advertise_mhome = 1;
1198		rt = rtget(myaddr, HOST_MASK);
1199		if (rt != 0) {
1200			if (rt->rt_ifp != ifp
1201			    || rt->rt_router != loopaddr) {
1202				rtdelete(rt);
1203				rt = 0;
1204			} else {
1205				loop_rts.rts_ifp = ifp;
1206				loop_rts.rts_metric = 0;
1207				loop_rts.rts_time = rt->rt_time;
1208				rtchange(rt, rt->rt_state | RS_MHOME,
1209					 &loop_rts, 0);
1210			}
1211		}
1212		if (rt == 0) {
1213			loop_rts.rts_ifp = ifp;
1214			loop_rts.rts_metric = 0;
1215			rtadd(myaddr, HOST_MASK, RS_MHOME, &loop_rts);
1216		}
1217	}
1218
1219	for (ifp = ifnet; ifp != 0; ifp = ifp1) {
1220		ifp1 = ifp->int_next;	/* because we may delete it */
1221
1222		/* Forget any interfaces that have disappeared.
1223		 */
1224		if (!(ifp->int_state & (IS_CHECKED | IS_REMOTE))) {
1225			trace_act("interface %s has disappeared",
1226				  ifp->int_name);
1227			ifdel(ifp);
1228			continue;
1229		}
1230
1231		if ((ifp->int_state & IS_BROKE)
1232		    && !(ifp->int_state & IS_PASSIVE))
1233			LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
1234
1235		/* If we ever have a RIPv1 interface, assume we always will.
1236		 * It might come back if it ever goes away.
1237		 */
1238		if (!(ifp->int_state & IS_NO_RIPV1_OUT) && supplier)
1239			have_ripv1_out = 1;
1240		if (!(ifp->int_state & IS_NO_RIPV1_IN))
1241			have_ripv1_in = 1;
1242	}
1243
1244	for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
1245		/* Ensure there is always a network route for interfaces,
1246		 * after any dead interfaces have been deleted, which
1247		 * might affect routes for point-to-point links.
1248		 */
1249		if (!addrouteforif(ifp))
1250			continue;
1251
1252		/* Add routes to the local end of point-to-point interfaces
1253		 * using loopback.
1254		 */
1255		if ((ifp->int_if_flags & IFF_POINTOPOINT)
1256		    && !(ifp->int_state & IS_REMOTE)
1257		    && foundloopback) {
1258			/* Delete any routes to the network address through
1259			 * foreign routers. Remove even static routes.
1260			 */
1261			del_static(ifp->int_addr, HOST_MASK, 0, 0);
1262			rt = rtget(ifp->int_addr, HOST_MASK);
1263			if (rt != 0 && rt->rt_router != loopaddr) {
1264				rtdelete(rt);
1265				rt = 0;
1266			}
1267			if (rt != 0) {
1268				if (!(rt->rt_state & RS_LOCAL)
1269				    || rt->rt_metric > ifp->int_metric) {
1270					ifp1 = ifp;
1271				} else {
1272					ifp1 = rt->rt_ifp;
1273				}
1274				loop_rts.rts_ifp = ifp1;
1275				loop_rts.rts_metric = 0;
1276				loop_rts.rts_time = rt->rt_time;
1277				rtchange(rt, ((rt->rt_state & ~RS_NET_SYN)
1278					      | (RS_IF|RS_LOCAL)),
1279					 &loop_rts, 0);
1280			} else {
1281				loop_rts.rts_ifp = ifp;
1282				loop_rts.rts_metric = 0;
1283				rtadd(ifp->int_addr, HOST_MASK,
1284				      (RS_IF | RS_LOCAL), &loop_rts);
1285			}
1286		}
1287	}
1288
1289	/* add the authority routes */
1290	for (intnetp = intnets; intnetp!=0; intnetp = intnetp->intnet_next) {
1291		rt = rtget(intnetp->intnet_addr, intnetp->intnet_mask);
1292		if (rt != 0
1293		    && !(rt->rt_state & RS_NO_NET_SYN)
1294		    && !(rt->rt_state & RS_NET_INT)) {
1295			rtdelete(rt);
1296			rt = 0;
1297		}
1298		if (rt == 0) {
1299			loop_rts.rts_ifp = 0;
1300			loop_rts.rts_metric = intnetp->intnet_metric-1;
1301			rtadd(intnetp->intnet_addr, intnetp->intnet_mask,
1302			      RS_NET_SYN | RS_NET_INT, &loop_rts);
1303		}
1304	}
1305
1306	prev_complaints = complaints;
1307}
1308
1309
1310static void
1311check_net_syn(struct interface *ifp)
1312{
1313	struct rt_entry *rt;
1314	static struct rt_spare new;
1315
1316
1317	/* Turn on the need to automatically synthesize a network route
1318	 * for this interface only if we are running RIPv1 on some other
1319	 * interface that is on a different class-A,B,or C network.
1320	 */
1321	if (have_ripv1_out || have_ripv1_in) {
1322		ifp->int_state |= IS_NEED_NET_SYN;
1323		rt = rtget(ifp->int_std_addr, ifp->int_std_mask);
1324		if (rt != 0
1325		    && 0 == (rt->rt_state & RS_NO_NET_SYN)
1326		    && (!(rt->rt_state & RS_NET_SYN)
1327			|| rt->rt_metric > ifp->int_metric)) {
1328			rtdelete(rt);
1329			rt = 0;
1330		}
1331		if (rt == 0) {
1332			new.rts_ifp = ifp;
1333			new.rts_gate = ifp->int_addr;
1334			new.rts_router = ifp->int_addr;
1335			new.rts_metric = ifp->int_metric;
1336			rtadd(ifp->int_std_addr, ifp->int_std_mask,
1337			      RS_NET_SYN, &new);
1338		}
1339
1340	} else {
1341		ifp->int_state &= ~IS_NEED_NET_SYN;
1342
1343		rt = rtget(ifp->int_std_addr,
1344			   ifp->int_std_mask);
1345		if (rt != 0
1346		    && (rt->rt_state & RS_NET_SYN)
1347		    && rt->rt_ifp == ifp)
1348			rtbad_sub(rt);
1349	}
1350}
1351
1352
1353/* Add route for interface if not currently installed.
1354 * Create route to other end if a point-to-point link,
1355 * otherwise a route to this (sub)network.
1356 */
1357int					/* 0=bad interface */
1358addrouteforif(struct interface *ifp)
1359{
1360	struct rt_entry *rt;
1361	static struct rt_spare new;
1362	naddr dst;
1363
1364
1365	/* skip sick interfaces
1366	 */
1367	if (ifp->int_state & IS_BROKE)
1368		return 0;
1369
1370	/* If the interface on a subnet, then install a RIPv1 route to
1371	 * the network as well (unless it is sick).
1372	 */
1373	if (ifp->int_state & IS_SUBNET)
1374		check_net_syn(ifp);
1375
1376	dst = (0 != (ifp->int_if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK))
1377	       ? ifp->int_dstaddr
1378	       : htonl(ifp->int_net));
1379
1380	new.rts_ifp = ifp;
1381	new.rts_router = ifp->int_addr;
1382	new.rts_gate = ifp->int_addr;
1383	new.rts_metric = ifp->int_metric;
1384	new.rts_time = now.tv_sec;
1385
1386	/* If we are going to send packets to the gateway,
1387	 * it must be reachable using our physical interfaces
1388	 */
1389	if ((ifp->int_state & IS_REMOTE)
1390	    && !(ifp->int_state & IS_EXTERNAL)
1391	    && !check_remote(ifp))
1392		return 0;
1393
1394	/* We are finished if the correct main interface route exists.
1395	 * The right route must be for the right interface, not synthesized
1396	 * from a subnet, be a "gateway" or not as appropriate, and so forth.
1397	 */
1398	del_static(dst, ifp->int_mask, 0, 0);
1399	rt = rtget(dst, ifp->int_mask);
1400	if (rt != 0) {
1401		if ((rt->rt_ifp != ifp
1402		     || rt->rt_router != ifp->int_addr)
1403		    && (!(ifp->int_state & IS_DUP)
1404			|| rt->rt_ifp == 0
1405			|| (rt->rt_ifp->int_state & IS_BROKE))) {
1406			rtdelete(rt);
1407			rt = 0;
1408		} else {
1409			rtchange(rt, ((rt->rt_state | RS_IF)
1410				      & ~(RS_NET_SYN | RS_LOCAL)),
1411				 &new, 0);
1412		}
1413	}
1414	if (rt == 0) {
1415		if (ifp->int_transitions++ > 0)
1416			trace_act("re-install interface %s",
1417				  ifp->int_name);
1418
1419		rtadd(dst, ifp->int_mask, RS_IF, &new);
1420	}
1421
1422	return 1;
1423}
1424