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      1 /*	$NetBSD: if.c,v 1.31 2017/10/02 11:02:19 maya 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 1.31 2017/10/02 11:02:19 maya Exp $");
     41 #elif defined(__FreeBSD__)
     42 __RCSID("$FreeBSD$");
     43 #else
     44 __RCSID("Revision: 2.27 ");
     45 #ident "Revision: 2.27 "
     46 #endif
     47 
     48 struct 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]
     57 struct interface *ahash_tbl[AHASH_LEN];
     58 
     59 #define BHASH_LEN 211			/* must be prime */
     60 #define BHASH(a) &bhash_tbl[(a)%BHASH_LEN]
     61 struct interface *bhash_tbl[BHASH_LEN];
     62 
     63 struct 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
     70 struct interface *nhash_tbl[NHASH_LEN];
     71 
     72 int	tot_interfaces;			/* # of remote and local interfaces */
     73 int	rip_interfaces;			/* # of interfaces doing RIP */
     74 int	foundloopback;			/* valid flag for loopaddr */
     75 naddr	loopaddr;			/* our address on loopback */
     76 struct	rt_spare loop_rts;
     77 
     78 struct timeval ifinit_timer;
     79 static 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 
     84 int	have_ripv1_out;			/* have a RIPv1 interface */
     85 int	have_ripv1_in;
     86 
     87 
     88 static struct interface**
     89 nhash(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  */
    103 void
    104 if_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  */
    151 struct interface *
    152 ifwithaddr(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  */
    189 struct interface *
    190 ifwithname(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 
    217 struct interface *
    218 ifwithindex(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  */
    244 struct interface *
    245 iflookup(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  */
    286 naddr					/* host byte order */
    287 std_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  */
    305 naddr
    306 ripv1_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 
    356 naddr
    357 ripv1_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  */
    374 int					/* 0=bad */
    375 check_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  */
    393 struct interface *
    394 check_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  */
    426 int					/* 0=bad */
    427 check_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  */
    456 static void
    457 ifdel(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  */
    546 void
    547 if_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  */
    561 void
    562 if_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  */
    593 int					/* 1=it was dead */
    594 if_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  */
    634 void
    635 rt_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  */
    679 void
    680 ifinit(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 
    774 			sdl = (const struct sockaddr_dl *)
    775 				((struct if_msghdr *)ifam + 1);
    776 			/* NUL-termination by memset, above. */
    777 			memcpy(ifs0.int_name, sdl->sdl_data,
    778 				MIN(sizeof(ifs0.int_name) - 1, sdl->sdl_nlen));
    779 			continue;
    780 		}
    781 		if (ifam->ifam_type != RTM_NEWADDR) {
    782 			logbad(1,"ifinit: out of sync");
    783 			continue;
    784 		}
    785 		rt_xaddrs(&info, (struct sockaddr *)(ifam+1),
    786 			  (struct sockaddr *)ifam2,
    787 			  ifam->ifam_addrs);
    788 
    789 		/* Prepare for the next address of this interface, which
    790 		 * will be an alias.
    791 		 * Do not output RIP or Router-Discovery packets via aliases.
    792 		 */
    793 		memcpy(&ifs, &ifs0, sizeof(ifs));
    794 		ifs0.int_state |= (IS_ALIAS | IS_NO_RIP_OUT | IS_NO_RDISC);
    795 
    796 		if (INFO_IFA(&info) == 0) {
    797 			if (iff_up(ifs.int_if_flags)) {
    798 				if (!(prev_complaints & COMP_NOADDR))
    799 					msglog("%s has no address",
    800 					       ifs.int_name);
    801 				complaints |= COMP_NOADDR;
    802 			}
    803 			continue;
    804 		}
    805 		if (INFO_IFA(&info)->sa_family != AF_INET) {
    806 			if (iff_up(ifs.int_if_flags)) {
    807 				if (!(prev_complaints & COMP_NOT_INET))
    808 					trace_act("%s: not AF_INET",
    809 						  ifs.int_name);
    810 				complaints |= COMP_NOT_INET;
    811 			}
    812 			continue;
    813 		}
    814 
    815 		ifs.int_addr = S_ADDR(INFO_IFA(&info));
    816 
    817 		if (ntohl(ifs.int_addr)>>24 == 0
    818 		    || ntohl(ifs.int_addr)>>24 == 0xff) {
    819 			if (iff_up(ifs.int_if_flags)) {
    820 				if (!(prev_complaints & COMP_BADADDR))
    821 					msglog("%s has a bad address",
    822 					       ifs.int_name);
    823 				complaints |= COMP_BADADDR;
    824 			}
    825 			continue;
    826 		}
    827 
    828 		if (ifs.int_if_flags & IFF_LOOPBACK) {
    829 			ifs.int_state |= IS_PASSIVE | IS_NO_RIP | IS_NO_RDISC;
    830 			ifs.int_dstaddr = ifs.int_addr;
    831 			ifs.int_mask = HOST_MASK;
    832 			ifs.int_ripv1_mask = HOST_MASK;
    833 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
    834 			ifs.int_net = ntohl(ifs.int_dstaddr);
    835 			if (!foundloopback) {
    836 				foundloopback = 1;
    837 				loopaddr = ifs.int_addr;
    838 				loop_rts.rts_gate = loopaddr;
    839 				loop_rts.rts_router = loopaddr;
    840 			}
    841 
    842 		} else if (ifs.int_if_flags & IFF_POINTOPOINT) {
    843 			if (INFO_BRD(&info) == 0
    844 			    || INFO_BRD(&info)->sa_family != AF_INET) {
    845 				if (iff_up(ifs.int_if_flags)) {
    846 					if (!(prev_complaints & COMP_NODST))
    847 						msglog("%s has a bad"
    848 						       " destination address",
    849 						       ifs.int_name);
    850 					complaints |= COMP_NODST;
    851 				}
    852 				continue;
    853 			}
    854 			ifs.int_dstaddr = S_ADDR(INFO_BRD(&info));
    855 			if (ntohl(ifs.int_dstaddr)>>24 == 0
    856 			    || ntohl(ifs.int_dstaddr)>>24 == 0xff) {
    857 				if (iff_up(ifs.int_if_flags)) {
    858 					if (!(prev_complaints & COMP_NODST))
    859 						msglog("%s has a bad"
    860 						       " destination address",
    861 						       ifs.int_name);
    862 					complaints |= COMP_NODST;
    863 				}
    864 				continue;
    865 			}
    866 			ifs.int_mask = HOST_MASK;
    867 			ifs.int_ripv1_mask = ntohl(S_ADDR(INFO_MASK(&info)));
    868 			ifs.int_std_mask = std_mask(ifs.int_dstaddr);
    869 			ifs.int_net = ntohl(ifs.int_dstaddr);
    870 
    871 		}  else {
    872 			if (INFO_MASK(&info) == 0) {
    873 				if (iff_up(ifs.int_if_flags)) {
    874 					if (!(prev_complaints & COMP_NOMASK))
    875 						msglog("%s has no netmask",
    876 						       ifs.int_name);
    877 					complaints |= COMP_NOMASK;
    878 				}
    879 				continue;
    880 			}
    881 			ifs.int_dstaddr = ifs.int_addr;
    882 			ifs.int_mask = ntohl(S_ADDR(INFO_MASK(&info)));
    883 			ifs.int_ripv1_mask = ifs.int_mask;
    884 			ifs.int_std_mask = std_mask(ifs.int_addr);
    885 			ifs.int_net = ntohl(ifs.int_addr) & ifs.int_mask;
    886 			if (ifs.int_mask != ifs.int_std_mask)
    887 				ifs.int_state |= IS_SUBNET;
    888 
    889 			if (ifs.int_if_flags & IFF_BROADCAST) {
    890 				if (INFO_BRD(&info) == 0) {
    891 					if (iff_up(ifs.int_if_flags)) {
    892 					    if (!(prev_complaints
    893 						  & COMP_NOBADR))
    894 						msglog("%s has"
    895 						       "no broadcast address",
    896 						       ifs.int_name);
    897 					    complaints |= COMP_NOBADR;
    898 					}
    899 					continue;
    900 				}
    901 				ifs.int_brdaddr = S_ADDR(INFO_BRD(&info));
    902 			}
    903 		}
    904 		ifs.int_std_net = ifs.int_net & ifs.int_std_mask;
    905 		ifs.int_std_addr = htonl(ifs.int_std_net);
    906 
    907 		/* Use a minimum metric of one.  Treat the interface metric
    908 		 * (default 0) as an increment to the hop count of one.
    909 		 *
    910 		 * The metric obtained from the routing socket dump of
    911 		 * interface addresses is wrong.  It is not set by the
    912 		 * SIOCSIFMETRIC ioctl.
    913 		 */
    914 #ifdef SIOCGIFMETRIC
    915 		strncpy(ifr.ifr_name, ifs.int_name, sizeof(ifr.ifr_name));
    916 		if (ioctl(rt_sock, SIOCGIFMETRIC, &ifr) < 0) {
    917 			DBGERR(1, "ioctl(SIOCGIFMETRIC)");
    918 			ifs.int_metric = 0;
    919 		} else {
    920 			ifs.int_metric = ifr.ifr_metric;
    921 		}
    922 #else
    923 		ifs.int_metric = ifam->ifam_metric;
    924 #endif
    925 		if (ifs.int_metric > HOPCNT_INFINITY) {
    926 			ifs.int_metric = 0;
    927 			if (!(prev_complaints & COMP_BAD_METRIC)
    928 			    && iff_up(ifs.int_if_flags)) {
    929 				complaints |= COMP_BAD_METRIC;
    930 				msglog("%s has a metric of %d",
    931 				       ifs.int_name, ifs.int_metric);
    932 			}
    933 		}
    934 
    935 		/* See if this is a familiar interface.
    936 		 * If so, stop worrying about it if it is the same.
    937 		 * Start it over if it now is to somewhere else, as happens
    938 		 * frequently with PPP and SLIP.
    939 		 */
    940 		ifp = ifwithname(ifs.int_name, ((ifs.int_state & IS_ALIAS)
    941 						? ifs.int_addr
    942 						: 0));
    943 		if (ifp != 0) {
    944 			ifp->int_state |= IS_CHECKED;
    945 
    946 			if (0 != ((ifp->int_if_flags ^ ifs.int_if_flags)
    947 				  & (IFF_BROADCAST
    948 				     | IFF_LOOPBACK
    949 				     | IFF_POINTOPOINT
    950 				     | IFF_MULTICAST))
    951 			    || 0 != ((ifp->int_state ^ ifs.int_state)
    952 				     & IS_ALIAS)
    953 			    || ifp->int_addr != ifs.int_addr
    954 			    || ifp->int_brdaddr != ifs.int_brdaddr
    955 			    || ifp->int_dstaddr != ifs.int_dstaddr
    956 			    || ifp->int_mask != ifs.int_mask
    957 			    || ifp->int_metric != ifs.int_metric) {
    958 				/* Forget old information about
    959 				 * a changed interface.
    960 				 */
    961 				trace_act("interface %s has changed",
    962 					  ifp->int_name);
    963 				ifdel(ifp);
    964 				ifp = 0;
    965 			}
    966 		}
    967 
    968 		if (ifp != 0) {
    969 			/* The primary representative of an alias worries
    970 			 * about how things are working.
    971 			 */
    972 			if (ifp->int_state & IS_ALIAS)
    973 				continue;
    974 
    975 			/* note interfaces that have been turned off
    976 			 */
    977 			if (!iff_up(ifs.int_if_flags)) {
    978 				if (iff_up(ifp->int_if_flags)) {
    979 					msglog("interface %s to %s turned off",
    980 					       ifp->int_name,
    981 					       naddr_ntoa(ifp->int_dstaddr));
    982 					if_bad(ifp);
    983 					ifp->int_if_flags &= ~IFF_UP;
    984 				} else if (now.tv_sec>(ifp->int_data.ts
    985 						       + CHECK_BAD_INTERVAL)) {
    986 					trace_act("interface %s has been off"
    987 						  " %lld seconds; forget it",
    988 						  ifp->int_name,
    989 						  (long long)now.tv_sec -
    990 						  ifp->int_data.ts);
    991 					ifdel(ifp);
    992 					ifp = 0;
    993 				}
    994 				continue;
    995 			}
    996 			/* or that were off and are now ok */
    997 			if (!iff_up(ifp->int_if_flags)) {
    998 				ifp->int_if_flags |= IFF_UP;
    999 				(void)if_ok(ifp, "");
   1000 			}
   1001 
   1002 			/* If it has been long enough,
   1003 			 * see if the interface is broken.
   1004 			 */
   1005 			if (now.tv_sec < ifp->int_data.ts+CHECK_BAD_INTERVAL)
   1006 				continue;
   1007 
   1008 			in = ifs.int_data.ipackets - ifp->int_data.ipackets;
   1009 			ierr = ifs.int_data.ierrors - ifp->int_data.ierrors;
   1010 			out = ifs.int_data.opackets - ifp->int_data.opackets;
   1011 			oerr = ifs.int_data.oerrors - ifp->int_data.oerrors;
   1012 
   1013 			/* If the interface just awoke, restart the counters.
   1014 			 */
   1015 			if (ifp->int_data.ts == 0) {
   1016 				ifp->int_data = ifs.int_data;
   1017 				continue;
   1018 			}
   1019 			ifp->int_data = ifs.int_data;
   1020 
   1021 			/* Withhold judgment when the short error
   1022 			 * counters wrap or the interface is reset.
   1023 			 */
   1024 			if (ierr < 0 || in < 0 || oerr < 0 || out < 0) {
   1025 				LIM_SEC(ifinit_timer,
   1026 					now.tv_sec+CHECK_BAD_INTERVAL);
   1027 				continue;
   1028 			}
   1029 
   1030 			/* Withhold judgement when there is no traffic
   1031 			 */
   1032 			if (in == 0 && out == 0 && ierr == 0 && oerr == 0)
   1033 				continue;
   1034 
   1035 			/* It is bad if input or output is not working.
   1036 			 * Require presistent problems before marking it dead.
   1037 			 */
   1038 			if ((in <= ierr && ierr > 0)
   1039 			    || (out <= oerr && oerr > 0)) {
   1040 				if (!(ifp->int_state & IS_SICK)) {
   1041 					trace_act("interface %s to %s"
   1042 						  " sick: in=%d ierr=%d"
   1043 						  " out=%d oerr=%d",
   1044 						  ifp->int_name,
   1045 						  naddr_ntoa(ifp->int_dstaddr),
   1046 						  in, ierr, out, oerr);
   1047 					if_sick(ifp);
   1048 					continue;
   1049 				}
   1050 				if (!(ifp->int_state & IS_BROKE)) {
   1051 					msglog("interface %s to %s broken:"
   1052 					       " in=%d ierr=%d out=%d oerr=%d",
   1053 					       ifp->int_name,
   1054 					       naddr_ntoa(ifp->int_dstaddr),
   1055 					       in, ierr, out, oerr);
   1056 					if_bad(ifp);
   1057 				}
   1058 				continue;
   1059 			}
   1060 
   1061 			/* otherwise, it is active and healthy
   1062 			 */
   1063 			ifp->int_act_time = now.tv_sec;
   1064 			(void)if_ok(ifp, "");
   1065 			continue;
   1066 		}
   1067 
   1068 		/* This is a new interface.
   1069 		 * If it is dead, forget it.
   1070 		 */
   1071 		if (!iff_up(ifs.int_if_flags))
   1072 			continue;
   1073 
   1074 		/* If it duplicates an existing interface,
   1075 		 * complain about it, mark the other one
   1076 		 * duplicated, and forget this one.
   1077 		 */
   1078 		ifp = check_dup(ifs.int_addr,ifs.int_dstaddr,ifs.int_mask,
   1079 				ifs.int_if_flags);
   1080 		if (ifp != 0) {
   1081 			/* Ignore duplicates of itself, caused by having
   1082 			 * IP aliases on the same network.
   1083 			 */
   1084 			if (!strcmp(ifp->int_name, ifs.int_name))
   1085 				continue;
   1086 
   1087 			if (!(prev_complaints & COMP_DUP)) {
   1088 				complaints |= COMP_DUP;
   1089 				msglog("%s (%s%s%s) is duplicated by"
   1090 				       " %s (%s%s%s)",
   1091 				       ifs.int_name,
   1092 				       addrname(ifs.int_addr,ifs.int_mask,1),
   1093 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
   1094 					? "-->" : ""),
   1095 				       ((ifs.int_if_flags & IFF_POINTOPOINT)
   1096 					? naddr_ntoa(ifs.int_dstaddr) : ""),
   1097 				       ifp->int_name,
   1098 				       addrname(ifp->int_addr,ifp->int_mask,1),
   1099 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
   1100 					? "-->" : ""),
   1101 				       ((ifp->int_if_flags & IFF_POINTOPOINT)
   1102 					? naddr_ntoa(ifp->int_dstaddr) : ""));
   1103 			}
   1104 			ifp->int_state |= IS_DUP;
   1105 			continue;
   1106 		}
   1107 
   1108 		if (0 == (ifs.int_if_flags & (IFF_POINTOPOINT | IFF_BROADCAST))
   1109 		    && !(ifs.int_state & IS_PASSIVE)) {
   1110 			trace_act("%s is neither broadcast, point-to-point,"
   1111 				  " nor loopback",
   1112 				  ifs.int_name);
   1113 			if (!(ifs.int_state & IFF_MULTICAST))
   1114 				ifs.int_state |= IS_NO_RDISC;
   1115 		}
   1116 
   1117 
   1118 		/* It is new and ok.   Add it to the list of interfaces
   1119 		 */
   1120 		ifp = (struct interface *)rtmalloc(sizeof(*ifp), "ifinit ifp");
   1121 		memcpy(ifp, &ifs, sizeof(*ifp));
   1122 		get_parms(ifp);
   1123 		if_link(ifp);
   1124 		trace_if("Add", ifp);
   1125 
   1126 		/* Notice likely bad netmask.
   1127 		 */
   1128 		if (!(prev_complaints & COMP_NETMASK)
   1129 		    && !(ifp->int_if_flags & IFF_POINTOPOINT)
   1130 		    && ifp->int_addr != RIP_DEFAULT) {
   1131 			for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
   1132 				if (ifp1->int_mask == ifp->int_mask)
   1133 					continue;
   1134 				if (ifp1->int_if_flags & IFF_POINTOPOINT)
   1135 					continue;
   1136 				if (ifp1->int_dstaddr == RIP_DEFAULT)
   1137 					continue;
   1138 				/* ignore aliases on the right network */
   1139 				if (!strcmp(ifp->int_name, ifp1->int_name))
   1140 					continue;
   1141 				if (on_net(ifp->int_dstaddr,
   1142 					   ifp1->int_net, ifp1->int_mask)
   1143 				    || on_net(ifp1->int_dstaddr,
   1144 					      ifp->int_net, ifp->int_mask)) {
   1145 					msglog("possible netmask problem"
   1146 					       " between %s:%s and %s:%s",
   1147 					       ifp->int_name,
   1148 					       addrname(htonl(ifp->int_net),
   1149 							ifp->int_mask, 1),
   1150 					       ifp1->int_name,
   1151 					       addrname(htonl(ifp1->int_net),
   1152 							ifp1->int_mask, 1));
   1153 					complaints |= COMP_NETMASK;
   1154 				}
   1155 			}
   1156 		}
   1157 
   1158 		if (!(ifp->int_state & IS_ALIAS)) {
   1159 			/* Count the # of directly connected networks.
   1160 			 */
   1161 			if (!(ifp->int_if_flags & IFF_LOOPBACK))
   1162 				tot_interfaces++;
   1163 			if (!IS_RIP_OFF(ifp->int_state))
   1164 				rip_interfaces++;
   1165 
   1166 			/* turn on router discovery and RIP If needed */
   1167 			if_ok_rdisc(ifp);
   1168 			rip_on(ifp);
   1169 		}
   1170 	}
   1171 
   1172 	/* If we are multi-homed and have at least two interfaces
   1173 	 * listening to RIP, then output by default.
   1174 	 */
   1175 	if (!supplier_set && rip_interfaces > 1)
   1176 		set_supplier();
   1177 
   1178 	/* If we are multi-homed, optionally advertise a route to
   1179 	 * our main address.
   1180 	 */
   1181 	if ((advertise_mhome && ifp)
   1182 	    || (tot_interfaces > 1
   1183 		&& mhome
   1184 		&& (ifp = ifwithaddr(myaddr, 0, 0)) != 0
   1185 		&& foundloopback)) {
   1186 		advertise_mhome = 1;
   1187 		rt = rtget(myaddr, HOST_MASK);
   1188 		if (rt != 0) {
   1189 			if (rt->rt_ifp != ifp
   1190 			    || rt->rt_router != loopaddr) {
   1191 				rtdelete(rt);
   1192 				rt = 0;
   1193 			} else {
   1194 				loop_rts.rts_ifp = ifp;
   1195 				loop_rts.rts_metric = 0;
   1196 				loop_rts.rts_time = rt->rt_time;
   1197 				rtchange(rt, rt->rt_state | RS_MHOME,
   1198 					 &loop_rts, 0);
   1199 			}
   1200 		}
   1201 		if (rt == 0) {
   1202 			loop_rts.rts_ifp = ifp;
   1203 			loop_rts.rts_metric = 0;
   1204 			rtadd(myaddr, HOST_MASK, RS_MHOME, &loop_rts);
   1205 		}
   1206 	}
   1207 
   1208 	for (ifp = ifnet; ifp != 0; ifp = ifp1) {
   1209 		ifp1 = ifp->int_next;	/* because we may delete it */
   1210 
   1211 		/* Forget any interfaces that have disappeared.
   1212 		 */
   1213 		if (!(ifp->int_state & (IS_CHECKED | IS_REMOTE))) {
   1214 			trace_act("interface %s has disappeared",
   1215 				  ifp->int_name);
   1216 			ifdel(ifp);
   1217 			continue;
   1218 		}
   1219 
   1220 		if ((ifp->int_state & IS_BROKE)
   1221 		    && !(ifp->int_state & IS_PASSIVE))
   1222 			LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
   1223 
   1224 		/* If we ever have a RIPv1 interface, assume we always will.
   1225 		 * It might come back if it ever goes away.
   1226 		 */
   1227 		if (!(ifp->int_state & IS_NO_RIPV1_OUT) && supplier)
   1228 			have_ripv1_out = 1;
   1229 		if (!(ifp->int_state & IS_NO_RIPV1_IN))
   1230 			have_ripv1_in = 1;
   1231 	}
   1232 
   1233 	for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
   1234 		/* Ensure there is always a network route for interfaces,
   1235 		 * after any dead interfaces have been deleted, which
   1236 		 * might affect routes for point-to-point links.
   1237 		 */
   1238 		if (!addrouteforif(ifp))
   1239 			continue;
   1240 
   1241 		/* Add routes to the local end of point-to-point interfaces
   1242 		 * using loopback.
   1243 		 */
   1244 		if ((ifp->int_if_flags & IFF_POINTOPOINT)
   1245 		    && !(ifp->int_state & IS_REMOTE)
   1246 		    && foundloopback) {
   1247 			/* Delete any routes to the network address through
   1248 			 * foreign routers. Remove even static routes.
   1249 			 */
   1250 			del_static(ifp->int_addr, HOST_MASK, 0, 0);
   1251 			rt = rtget(ifp->int_addr, HOST_MASK);
   1252 			if (rt != 0 && rt->rt_router != loopaddr) {
   1253 				rtdelete(rt);
   1254 				rt = 0;
   1255 			}
   1256 			if (rt != 0) {
   1257 				if (!(rt->rt_state & RS_LOCAL)
   1258 				    || rt->rt_metric > ifp->int_metric) {
   1259 					ifp1 = ifp;
   1260 				} else {
   1261 					ifp1 = rt->rt_ifp;
   1262 				}
   1263 				loop_rts.rts_ifp = ifp1;
   1264 				loop_rts.rts_metric = 0;
   1265 				loop_rts.rts_time = rt->rt_time;
   1266 				rtchange(rt, ((rt->rt_state & ~RS_NET_SYN)
   1267 					      | (RS_IF|RS_LOCAL)),
   1268 					 &loop_rts, 0);
   1269 			} else {
   1270 				loop_rts.rts_ifp = ifp;
   1271 				loop_rts.rts_metric = 0;
   1272 				rtadd(ifp->int_addr, HOST_MASK,
   1273 				      (RS_IF | RS_LOCAL), &loop_rts);
   1274 			}
   1275 		}
   1276 	}
   1277 
   1278 	/* add the authority routes */
   1279 	for (intnetp = intnets; intnetp!=0; intnetp = intnetp->intnet_next) {
   1280 		rt = rtget(intnetp->intnet_addr, intnetp->intnet_mask);
   1281 		if (rt != 0
   1282 		    && !(rt->rt_state & RS_NO_NET_SYN)
   1283 		    && !(rt->rt_state & RS_NET_INT)) {
   1284 			rtdelete(rt);
   1285 			rt = 0;
   1286 		}
   1287 		if (rt == 0) {
   1288 			loop_rts.rts_ifp = 0;
   1289 			loop_rts.rts_metric = intnetp->intnet_metric-1;
   1290 			rtadd(intnetp->intnet_addr, intnetp->intnet_mask,
   1291 			      RS_NET_SYN | RS_NET_INT, &loop_rts);
   1292 		}
   1293 	}
   1294 
   1295 	prev_complaints = complaints;
   1296 }
   1297 
   1298 
   1299 static void
   1300 check_net_syn(struct interface *ifp)
   1301 {
   1302 	struct rt_entry *rt;
   1303 	static struct rt_spare new;
   1304 
   1305 
   1306 	/* Turn on the need to automatically synthesize a network route
   1307 	 * for this interface only if we are running RIPv1 on some other
   1308 	 * interface that is on a different class-A,B,or C network.
   1309 	 */
   1310 	if (have_ripv1_out || have_ripv1_in) {
   1311 		ifp->int_state |= IS_NEED_NET_SYN;
   1312 		rt = rtget(ifp->int_std_addr, ifp->int_std_mask);
   1313 		if (rt != 0
   1314 		    && 0 == (rt->rt_state & RS_NO_NET_SYN)
   1315 		    && (!(rt->rt_state & RS_NET_SYN)
   1316 			|| rt->rt_metric > ifp->int_metric)) {
   1317 			rtdelete(rt);
   1318 			rt = 0;
   1319 		}
   1320 		if (rt == 0) {
   1321 			new.rts_ifp = ifp;
   1322 			new.rts_gate = ifp->int_addr;
   1323 			new.rts_router = ifp->int_addr;
   1324 			new.rts_metric = ifp->int_metric;
   1325 			rtadd(ifp->int_std_addr, ifp->int_std_mask,
   1326 			      RS_NET_SYN, &new);
   1327 		}
   1328 
   1329 	} else {
   1330 		ifp->int_state &= ~IS_NEED_NET_SYN;
   1331 
   1332 		rt = rtget(ifp->int_std_addr,
   1333 			   ifp->int_std_mask);
   1334 		if (rt != 0
   1335 		    && (rt->rt_state & RS_NET_SYN)
   1336 		    && rt->rt_ifp == ifp)
   1337 			rtbad_sub(rt);
   1338 	}
   1339 }
   1340 
   1341 
   1342 /* Add route for interface if not currently installed.
   1343  * Create route to other end if a point-to-point link,
   1344  * otherwise a route to this (sub)network.
   1345  */
   1346 int					/* 0=bad interface */
   1347 addrouteforif(struct interface *ifp)
   1348 {
   1349 	struct rt_entry *rt;
   1350 	static struct rt_spare new;
   1351 	naddr dst;
   1352 
   1353 
   1354 	/* skip sick interfaces
   1355 	 */
   1356 	if (ifp->int_state & IS_BROKE)
   1357 		return 0;
   1358 
   1359 	/* If the interface on a subnet, then install a RIPv1 route to
   1360 	 * the network as well (unless it is sick).
   1361 	 */
   1362 	if (ifp->int_state & IS_SUBNET)
   1363 		check_net_syn(ifp);
   1364 
   1365 	dst = (0 != (ifp->int_if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK))
   1366 	       ? ifp->int_dstaddr
   1367 	       : htonl(ifp->int_net));
   1368 
   1369 	new.rts_ifp = ifp;
   1370 	new.rts_router = ifp->int_addr;
   1371 	new.rts_gate = ifp->int_addr;
   1372 	new.rts_metric = ifp->int_metric;
   1373 	new.rts_time = now.tv_sec;
   1374 
   1375 	/* If we are going to send packets to the gateway,
   1376 	 * it must be reachable using our physical interfaces
   1377 	 */
   1378 	if ((ifp->int_state & IS_REMOTE)
   1379 	    && !(ifp->int_state & IS_EXTERNAL)
   1380 	    && !check_remote(ifp))
   1381 		return 0;
   1382 
   1383 	/* We are finished if the correct main interface route exists.
   1384 	 * The right route must be for the right interface, not synthesized
   1385 	 * from a subnet, be a "gateway" or not as appropriate, and so forth.
   1386 	 */
   1387 	del_static(dst, ifp->int_mask, 0, 0);
   1388 	rt = rtget(dst, ifp->int_mask);
   1389 	if (rt != 0) {
   1390 		if ((rt->rt_ifp != ifp
   1391 		     || rt->rt_router != ifp->int_addr)
   1392 		    && (!(ifp->int_state & IS_DUP)
   1393 			|| rt->rt_ifp == 0
   1394 			|| (rt->rt_ifp->int_state & IS_BROKE))) {
   1395 			rtdelete(rt);
   1396 			rt = 0;
   1397 		} else {
   1398 			rtchange(rt, ((rt->rt_state | RS_IF)
   1399 				      & ~(RS_NET_SYN | RS_LOCAL)),
   1400 				 &new, 0);
   1401 		}
   1402 	}
   1403 	if (rt == 0) {
   1404 		if (ifp->int_transitions++ > 0)
   1405 			trace_act("re-install interface %s",
   1406 				  ifp->int_name);
   1407 
   1408 		rtadd(dst, ifp->int_mask, RS_IF, &new);
   1409 	}
   1410 
   1411 	return 1;
   1412 }
   1413