xref: /netbsd-src/sys/netinet/in.c (revision 3b01aba77a7a698587faaae455bbfe740923c1f5)
1 /*	$NetBSD: in.c,v 1.68 2001/07/27 02:04:08 itojun Exp $	*/
2 
3 /*
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * 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 project 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 PROJECT 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 PROJECT 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 /*-
33  * Copyright (c) 1998 The NetBSD Foundation, Inc.
34  * All rights reserved.
35  *
36  * This code is derived from software contributed to The NetBSD Foundation
37  * by Public Access Networks Corporation ("Panix").  It was developed under
38  * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon.
39  *
40  * Redistribution and use in source and binary forms, with or without
41  * modification, are permitted provided that the following conditions
42  * are met:
43  * 1. Redistributions of source code must retain the above copyright
44  *    notice, this list of conditions and the following disclaimer.
45  * 2. Redistributions in binary form must reproduce the above copyright
46  *    notice, this list of conditions and the following disclaimer in the
47  *    documentation and/or other materials provided with the distribution.
48  * 3. All advertising materials mentioning features or use of this software
49  *    must display the following acknowledgement:
50  *	This product includes software developed by the NetBSD
51  *	Foundation, Inc. and its contributors.
52  * 4. Neither the name of The NetBSD Foundation nor the names of its
53  *    contributors may be used to endorse or promote products derived
54  *    from this software without specific prior written permission.
55  *
56  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
57  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
58  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
59  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
60  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
61  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
62  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
63  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
64  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
65  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
66  * POSSIBILITY OF SUCH DAMAGE.
67  */
68 
69 /*
70  * Copyright (c) 1982, 1986, 1991, 1993
71  *	The Regents of the University of California.  All rights reserved.
72  *
73  * Redistribution and use in source and binary forms, with or without
74  * modification, are permitted provided that the following conditions
75  * are met:
76  * 1. Redistributions of source code must retain the above copyright
77  *    notice, this list of conditions and the following disclaimer.
78  * 2. Redistributions in binary form must reproduce the above copyright
79  *    notice, this list of conditions and the following disclaimer in the
80  *    documentation and/or other materials provided with the distribution.
81  * 3. All advertising materials mentioning features or use of this software
82  *    must display the following acknowledgement:
83  *	This product includes software developed by the University of
84  *	California, Berkeley and its contributors.
85  * 4. Neither the name of the University nor the names of its contributors
86  *    may be used to endorse or promote products derived from this software
87  *    without specific prior written permission.
88  *
89  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
90  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
91  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
92  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
93  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
94  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
95  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
96  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
97  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
98  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
99  * SUCH DAMAGE.
100  *
101  *	@(#)in.c	8.4 (Berkeley) 1/9/95
102  */
103 
104 #include "opt_inet.h"
105 #include "opt_inet_conf.h"
106 #include "opt_mrouting.h"
107 
108 #include <sys/param.h>
109 #include <sys/ioctl.h>
110 #include <sys/errno.h>
111 #include <sys/malloc.h>
112 #include <sys/socket.h>
113 #include <sys/socketvar.h>
114 #include <sys/systm.h>
115 #include <sys/proc.h>
116 
117 #include <net/if.h>
118 #include <net/route.h>
119 
120 #include <net/if_ether.h>
121 
122 #include <netinet/in_systm.h>
123 #include <netinet/in.h>
124 #include <netinet/in_var.h>
125 #include <netinet/if_inarp.h>
126 #include <netinet/ip_mroute.h>
127 #include <netinet/igmp_var.h>
128 
129 #ifdef INET
130 
131 static int in_mask2len __P((struct in_addr *));
132 static void in_len2mask __P((struct in_addr *, int));
133 static int in_lifaddr_ioctl __P((struct socket *, u_long, caddr_t,
134 	struct ifnet *, struct proc *));
135 
136 static int in_addprefix __P((struct in_ifaddr *, int));
137 static int in_scrubprefix __P((struct in_ifaddr *));
138 
139 #ifndef SUBNETSARELOCAL
140 #define	SUBNETSARELOCAL	1
141 #endif
142 
143 #ifndef HOSTZEROBROADCAST
144 #define HOSTZEROBROADCAST 1
145 #endif
146 
147 int subnetsarelocal = SUBNETSARELOCAL;
148 int hostzeroisbroadcast = HOSTZEROBROADCAST;
149 
150 /*
151  * This list is used to keep track of in_multi chains which belong to
152  * deleted interface addresses.  We use in_ifaddr so that a chain head
153  * won't be deallocated until all multicast address record are deleted.
154  */
155 static TAILQ_HEAD(, in_ifaddr) in_mk = TAILQ_HEAD_INITIALIZER(in_mk);
156 
157 /*
158  * Return 1 if an internet address is for a ``local'' host
159  * (one to which we have a connection).  If subnetsarelocal
160  * is true, this includes other subnets of the local net.
161  * Otherwise, it includes only the directly-connected (sub)nets.
162  */
163 int
164 in_localaddr(in)
165 	struct in_addr in;
166 {
167 	struct in_ifaddr *ia;
168 
169 	if (subnetsarelocal) {
170 		for (ia = in_ifaddr.tqh_first; ia != 0; ia = ia->ia_list.tqe_next)
171 			if ((in.s_addr & ia->ia_netmask) == ia->ia_net)
172 				return (1);
173 	} else {
174 		for (ia = in_ifaddr.tqh_first; ia != 0; ia = ia->ia_list.tqe_next)
175 			if ((in.s_addr & ia->ia_subnetmask) == ia->ia_subnet)
176 				return (1);
177 	}
178 	return (0);
179 }
180 
181 /*
182  * Determine whether an IP address is in a reserved set of addresses
183  * that may not be forwarded, or whether datagrams to that destination
184  * may be forwarded.
185  */
186 int
187 in_canforward(in)
188 	struct in_addr in;
189 {
190 	u_int32_t net;
191 
192 	if (IN_EXPERIMENTAL(in.s_addr) || IN_MULTICAST(in.s_addr))
193 		return (0);
194 	if (IN_CLASSA(in.s_addr)) {
195 		net = in.s_addr & IN_CLASSA_NET;
196 		if (net == 0 || net == htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
197 			return (0);
198 	}
199 	return (1);
200 }
201 
202 /*
203  * Trim a mask in a sockaddr
204  */
205 void
206 in_socktrim(ap)
207 	struct sockaddr_in *ap;
208 {
209 	char *cplim = (char *) &ap->sin_addr;
210 	char *cp = (char *) (&ap->sin_addr + 1);
211 
212 	ap->sin_len = 0;
213 	while (--cp >= cplim)
214 		if (*cp) {
215 			(ap)->sin_len = cp - (char *) (ap) + 1;
216 			break;
217 		}
218 }
219 
220 /*
221  *  Routine to take an Internet address and convert into a
222  *  "dotted quad" representation for printing.
223  */
224 const char *
225 in_fmtaddr(addr)
226 	struct in_addr addr;
227 {
228 	static char buf[sizeof("123.456.789.123")];
229 
230 	addr.s_addr = ntohl(addr.s_addr);
231 
232 	sprintf(buf, "%d.%d.%d.%d",
233 		(addr.s_addr >> 24) & 0xFF,
234 		(addr.s_addr >> 16) & 0xFF,
235 		(addr.s_addr >>  8) & 0xFF,
236 		(addr.s_addr >>  0) & 0xFF);
237 	return buf;
238 }
239 
240 /*
241  * Maintain the "in_maxmtu" variable, which is the largest
242  * mtu for non-local interfaces with AF_INET addresses assigned
243  * to them that are up.
244  */
245 unsigned long in_maxmtu;
246 
247 void
248 in_setmaxmtu()
249 {
250 	struct in_ifaddr *ia;
251 	struct ifnet *ifp;
252 	unsigned long maxmtu = 0;
253 
254 	for (ia = in_ifaddr.tqh_first; ia != 0; ia = ia->ia_list.tqe_next) {
255 		if ((ifp = ia->ia_ifp) == 0)
256 			continue;
257 		if ((ifp->if_flags & (IFF_UP|IFF_LOOPBACK)) != IFF_UP)
258 			continue;
259 		if (ifp->if_mtu > maxmtu)
260 			maxmtu = ifp->if_mtu;
261 	}
262 	if (maxmtu)
263 		in_maxmtu = maxmtu;
264 }
265 
266 static int
267 in_mask2len(mask)
268 	struct in_addr *mask;
269 {
270 	int x, y;
271 	u_char *p;
272 
273 	p = (u_char *)mask;
274 	for (x = 0; x < sizeof(*mask); x++) {
275 		if (p[x] != 0xff)
276 			break;
277 	}
278 	y = 0;
279 	if (x < sizeof(*mask)) {
280 		for (y = 0; y < 8; y++) {
281 			if ((p[x] & (0x80 >> y)) == 0)
282 				break;
283 		}
284 	}
285 	return x * 8 + y;
286 }
287 
288 static void
289 in_len2mask(mask, len)
290 	struct in_addr *mask;
291 	int len;
292 {
293 	int i;
294 	u_char *p;
295 
296 	p = (u_char *)mask;
297 	bzero(mask, sizeof(*mask));
298 	for (i = 0; i < len / 8; i++)
299 		p[i] = 0xff;
300 	if (len % 8)
301 		p[i] = (0xff00 >> (len % 8)) & 0xff;
302 }
303 
304 /*
305  * Generic internet control operations (ioctl's).
306  * Ifp is 0 if not an interface-specific ioctl.
307  */
308 /* ARGSUSED */
309 int
310 in_control(so, cmd, data, ifp, p)
311 	struct socket *so;
312 	u_long cmd;
313 	caddr_t data;
314 	struct ifnet *ifp;
315 	struct proc *p;
316 {
317 	struct ifreq *ifr = (struct ifreq *)data;
318 	struct in_ifaddr *ia = 0;
319 	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
320 	struct sockaddr_in oldaddr;
321 	int error, hostIsNew, maskIsNew;
322 	int newifaddr;
323 
324 	switch (cmd) {
325 	case SIOCALIFADDR:
326 	case SIOCDLIFADDR:
327 		if (p == 0 || (error = suser(p->p_ucred, &p->p_acflag)))
328 			return(EPERM);
329 		/*fall through*/
330 	case SIOCGLIFADDR:
331 		if (!ifp)
332 			return EINVAL;
333 		return in_lifaddr_ioctl(so, cmd, data, ifp, p);
334 	}
335 
336 	/*
337 	 * Find address for this interface, if it exists.
338 	 */
339 	if (ifp)
340 		IFP_TO_IA(ifp, ia);
341 
342 	switch (cmd) {
343 
344 	case SIOCAIFADDR:
345 	case SIOCDIFADDR:
346 	case SIOCGIFALIAS:
347 		if (ifra->ifra_addr.sin_family == AF_INET)
348 			for (ia = IN_IFADDR_HASH(ifra->ifra_addr.sin_addr.s_addr).lh_first;
349 			    ia != 0; ia = ia->ia_hash.le_next) {
350 				if (ia->ia_ifp == ifp  &&
351 				    in_hosteq(ia->ia_addr.sin_addr,
352 				    ifra->ifra_addr.sin_addr))
353 					break;
354 			}
355 		if (cmd == SIOCDIFADDR) {
356 			if (ia == 0)
357 				return (EADDRNOTAVAIL);
358 #if 1 /*def COMPAT_43*/
359 			if (ifra->ifra_addr.sin_family == AF_UNSPEC)
360 				ifra->ifra_addr.sin_family = AF_INET;
361 #endif
362 		}
363 		/* FALLTHROUGH */
364 	case SIOCSIFADDR:
365 	case SIOCSIFDSTADDR:
366 		if (ifra->ifra_addr.sin_family != AF_INET)
367 			return (EAFNOSUPPORT);
368 		/* FALLTHROUGH */
369 	case SIOCSIFNETMASK:
370 		if (ifp == 0)
371 			panic("in_control");
372 
373 		if (cmd == SIOCGIFALIAS)
374 			break;
375 
376 		if (p == 0 || (error = suser(p->p_ucred, &p->p_acflag)))
377 			return (EPERM);
378 
379 		if (ia == 0) {
380 			MALLOC(ia, struct in_ifaddr *, sizeof(*ia),
381 			       M_IFADDR, M_WAITOK);
382 			if (ia == 0)
383 				return (ENOBUFS);
384 			bzero((caddr_t)ia, sizeof *ia);
385 			TAILQ_INSERT_TAIL(&in_ifaddr, ia, ia_list);
386 			IFAREF(&ia->ia_ifa);
387 			TAILQ_INSERT_TAIL(&ifp->if_addrlist, &ia->ia_ifa,
388 			    ifa_list);
389 			IFAREF(&ia->ia_ifa);
390 			ia->ia_ifa.ifa_addr = sintosa(&ia->ia_addr);
391 			ia->ia_ifa.ifa_dstaddr = sintosa(&ia->ia_dstaddr);
392 			ia->ia_ifa.ifa_netmask = sintosa(&ia->ia_sockmask);
393 			ia->ia_sockmask.sin_len = 8;
394 			if (ifp->if_flags & IFF_BROADCAST) {
395 				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
396 				ia->ia_broadaddr.sin_family = AF_INET;
397 			}
398 			ia->ia_ifp = ifp;
399 			LIST_INIT(&ia->ia_multiaddrs);
400 			newifaddr = 1;
401 		} else
402 			newifaddr = 0;
403 		break;
404 
405 	case SIOCSIFBRDADDR:
406 		if (p == 0 || (error = suser(p->p_ucred, &p->p_acflag)))
407 			return (EPERM);
408 		/* FALLTHROUGH */
409 
410 	case SIOCGIFADDR:
411 	case SIOCGIFNETMASK:
412 	case SIOCGIFDSTADDR:
413 	case SIOCGIFBRDADDR:
414 		if (ia == 0)
415 			return (EADDRNOTAVAIL);
416 		break;
417 	}
418 	switch (cmd) {
419 
420 	case SIOCGIFADDR:
421 		*satosin(&ifr->ifr_addr) = ia->ia_addr;
422 		break;
423 
424 	case SIOCGIFBRDADDR:
425 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
426 			return (EINVAL);
427 		*satosin(&ifr->ifr_dstaddr) = ia->ia_broadaddr;
428 		break;
429 
430 	case SIOCGIFDSTADDR:
431 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
432 			return (EINVAL);
433 		*satosin(&ifr->ifr_dstaddr) = ia->ia_dstaddr;
434 		break;
435 
436 	case SIOCGIFNETMASK:
437 		*satosin(&ifr->ifr_addr) = ia->ia_sockmask;
438 		break;
439 
440 	case SIOCSIFDSTADDR:
441 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
442 			return (EINVAL);
443 		oldaddr = ia->ia_dstaddr;
444 		ia->ia_dstaddr = *satosin(&ifr->ifr_dstaddr);
445 		if (ifp->if_ioctl && (error = (*ifp->if_ioctl)
446 					(ifp, SIOCSIFDSTADDR, (caddr_t)ia))) {
447 			ia->ia_dstaddr = oldaddr;
448 			return (error);
449 		}
450 		if (ia->ia_flags & IFA_ROUTE) {
451 			ia->ia_ifa.ifa_dstaddr = sintosa(&oldaddr);
452 			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
453 			ia->ia_ifa.ifa_dstaddr = sintosa(&ia->ia_dstaddr);
454 			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
455 		}
456 		break;
457 
458 	case SIOCSIFBRDADDR:
459 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
460 			return (EINVAL);
461 		ia->ia_broadaddr = *satosin(&ifr->ifr_broadaddr);
462 		break;
463 
464 	case SIOCSIFADDR:
465 		error = in_ifinit(ifp, ia, satosin(&ifr->ifr_addr), 1);
466 		return error;
467 
468 	case SIOCSIFNETMASK:
469 		ia->ia_subnetmask = ia->ia_sockmask.sin_addr.s_addr =
470 		    ifra->ifra_addr.sin_addr.s_addr;
471 		break;
472 
473 	case SIOCAIFADDR:
474 		maskIsNew = 0;
475 		hostIsNew = 1;
476 		error = 0;
477 		if (ia->ia_addr.sin_family == AF_INET) {
478 			if (ifra->ifra_addr.sin_len == 0) {
479 				ifra->ifra_addr = ia->ia_addr;
480 				hostIsNew = 0;
481 			} else if (in_hosteq(ia->ia_addr.sin_addr, ifra->ifra_addr.sin_addr))
482 				hostIsNew = 0;
483 		}
484 		if (ifra->ifra_mask.sin_len) {
485 			in_ifscrub(ifp, ia);
486 			ia->ia_sockmask = ifra->ifra_mask;
487 			ia->ia_subnetmask = ia->ia_sockmask.sin_addr.s_addr;
488 			maskIsNew = 1;
489 		}
490 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
491 		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
492 			in_ifscrub(ifp, ia);
493 			ia->ia_dstaddr = ifra->ifra_dstaddr;
494 			maskIsNew  = 1; /* We lie; but the effect's the same */
495 		}
496 		if (ifra->ifra_addr.sin_family == AF_INET &&
497 		    (hostIsNew || maskIsNew)) {
498 			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
499 		}
500 		if ((ifp->if_flags & IFF_BROADCAST) &&
501 		    (ifra->ifra_broadaddr.sin_family == AF_INET))
502 			ia->ia_broadaddr = ifra->ifra_broadaddr;
503 		return (error);
504 
505 	case SIOCGIFALIAS:
506 		ifra->ifra_mask = ia->ia_sockmask;
507 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
508 		    (ia->ia_dstaddr.sin_family == AF_INET))
509 			ifra->ifra_dstaddr = ia->ia_dstaddr;
510 		else if ((ifp->if_flags & IFF_BROADCAST) &&
511 		    (ia->ia_broadaddr.sin_family == AF_INET))
512 			ifra->ifra_broadaddr = ia->ia_broadaddr;
513 		else
514 			bzero(&ifra->ifra_broadaddr,
515 			      sizeof(ifra->ifra_broadaddr));
516 		return 0;
517 
518 	case SIOCDIFADDR:
519 		in_purgeaddr(&ia->ia_ifa, ifp);
520 		break;
521 
522 #ifdef MROUTING
523 	case SIOCGETVIFCNT:
524 	case SIOCGETSGCNT:
525 		return (mrt_ioctl(so, cmd, data));
526 #endif /* MROUTING */
527 
528 	default:
529 		if (ifp == 0 || ifp->if_ioctl == 0)
530 			return (EOPNOTSUPP);
531 		error = (*ifp->if_ioctl)(ifp, cmd, data);
532 		in_setmaxmtu();
533 		return(error);
534 	}
535 	return (0);
536 }
537 
538 void
539 in_purgeaddr(ifa, ifp)
540 	struct ifaddr *ifa;
541 	struct ifnet *ifp;
542 {
543 	struct in_ifaddr *ia = (void *) ifa;
544 
545 	in_ifscrub(ifp, ia);
546 	LIST_REMOVE(ia, ia_hash);
547 	TAILQ_REMOVE(&ifp->if_addrlist, &ia->ia_ifa, ifa_list);
548 	IFAFREE(&ia->ia_ifa);
549 	TAILQ_REMOVE(&in_ifaddr, ia, ia_list);
550 	if (ia->ia_allhosts != NULL)
551 		in_delmulti(ia->ia_allhosts);
552 	if (LIST_FIRST(&ia->ia_multiaddrs) != NULL &&
553 	    /*
554 	     * If the interface is going away, don't bother to save
555 	     * the multicast entries.
556 	     */
557 	    ifp->if_output != if_nulloutput)
558 		in_savemkludge(ia);
559 	IFAFREE(&ia->ia_ifa);
560 	in_setmaxmtu();
561 }
562 
563 void
564 in_purgeif(ifp)
565 	struct ifnet *ifp;
566 {
567 	struct ifaddr *ifa, *nifa;
568 
569 	for (ifa = TAILQ_FIRST(&ifp->if_addrlist); ifa != NULL; ifa = nifa) {
570 		nifa = TAILQ_NEXT(ifa, ifa_list);
571 		if (ifa->ifa_addr->sa_family != AF_INET)
572 			continue;
573 		in_purgeaddr(ifa, ifp);
574 	}
575 	in_purgemkludge(ifp);
576 }
577 
578 /*
579  * SIOC[GAD]LIFADDR.
580  *	SIOCGLIFADDR: get first address. (???)
581  *	SIOCGLIFADDR with IFLR_PREFIX:
582  *		get first address that matches the specified prefix.
583  *	SIOCALIFADDR: add the specified address.
584  *	SIOCALIFADDR with IFLR_PREFIX:
585  *		EINVAL since we can't deduce hostid part of the address.
586  *	SIOCDLIFADDR: delete the specified address.
587  *	SIOCDLIFADDR with IFLR_PREFIX:
588  *		delete the first address that matches the specified prefix.
589  * return values:
590  *	EINVAL on invalid parameters
591  *	EADDRNOTAVAIL on prefix match failed/specified address not found
592  *	other values may be returned from in_ioctl()
593  */
594 static int
595 in_lifaddr_ioctl(so, cmd, data, ifp, p)
596 	struct socket *so;
597 	u_long cmd;
598 	caddr_t	data;
599 	struct ifnet *ifp;
600 	struct proc *p;
601 {
602 	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
603 	struct ifaddr *ifa;
604 	struct sockaddr *sa;
605 
606 	/* sanity checks */
607 	if (!data || !ifp) {
608 		panic("invalid argument to in_lifaddr_ioctl");
609 		/*NOTRECHED*/
610 	}
611 
612 	switch (cmd) {
613 	case SIOCGLIFADDR:
614 		/* address must be specified on GET with IFLR_PREFIX */
615 		if ((iflr->flags & IFLR_PREFIX) == 0)
616 			break;
617 		/*FALLTHROUGH*/
618 	case SIOCALIFADDR:
619 	case SIOCDLIFADDR:
620 		/* address must be specified on ADD and DELETE */
621 		sa = (struct sockaddr *)&iflr->addr;
622 		if (sa->sa_family != AF_INET)
623 			return EINVAL;
624 		if (sa->sa_len != sizeof(struct sockaddr_in))
625 			return EINVAL;
626 		/* XXX need improvement */
627 		sa = (struct sockaddr *)&iflr->dstaddr;
628 		if (sa->sa_family
629 		 && sa->sa_family != AF_INET)
630 			return EINVAL;
631 		if (sa->sa_len && sa->sa_len != sizeof(struct sockaddr_in))
632 			return EINVAL;
633 		break;
634 	default: /*shouldn't happen*/
635 #if 0
636 		panic("invalid cmd to in_lifaddr_ioctl");
637 		/*NOTREACHED*/
638 #else
639 		return EOPNOTSUPP;
640 #endif
641 	}
642 	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
643 		return EINVAL;
644 
645 	switch (cmd) {
646 	case SIOCALIFADDR:
647 	    {
648 		struct in_aliasreq ifra;
649 
650 		if (iflr->flags & IFLR_PREFIX)
651 			return EINVAL;
652 
653 		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
654 		bzero(&ifra, sizeof(ifra));
655 		bcopy(iflr->iflr_name, ifra.ifra_name,
656 			sizeof(ifra.ifra_name));
657 
658 		bcopy(&iflr->addr, &ifra.ifra_addr,
659 			((struct sockaddr *)&iflr->addr)->sa_len);
660 
661 		if (((struct sockaddr *)&iflr->dstaddr)->sa_family) {	/*XXX*/
662 			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
663 				((struct sockaddr *)&iflr->dstaddr)->sa_len);
664 		}
665 
666 		ifra.ifra_mask.sin_family = AF_INET;
667 		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
668 		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
669 
670 		return in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, p);
671 	    }
672 	case SIOCGLIFADDR:
673 	case SIOCDLIFADDR:
674 	    {
675 		struct in_ifaddr *ia;
676 		struct in_addr mask, candidate, match;
677 		struct sockaddr_in *sin;
678 		int cmp;
679 
680 		bzero(&mask, sizeof(mask));
681 		if (iflr->flags & IFLR_PREFIX) {
682 			/* lookup a prefix rather than address. */
683 			in_len2mask(&mask, iflr->prefixlen);
684 
685 			sin = (struct sockaddr_in *)&iflr->addr;
686 			match.s_addr = sin->sin_addr.s_addr;
687 			match.s_addr &= mask.s_addr;
688 
689 			/* if you set extra bits, that's wrong */
690 			if (match.s_addr != sin->sin_addr.s_addr)
691 				return EINVAL;
692 
693 			cmp = 1;
694 		} else {
695 			if (cmd == SIOCGLIFADDR) {
696 				/* on getting an address, take the 1st match */
697 				cmp = 0;	/*XXX*/
698 			} else {
699 				/* on deleting an address, do exact match */
700 				in_len2mask(&mask, 32);
701 				sin = (struct sockaddr_in *)&iflr->addr;
702 				match.s_addr = sin->sin_addr.s_addr;
703 
704 				cmp = 1;
705 			}
706 		}
707 
708 		for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next) {
709 			if (ifa->ifa_addr->sa_family != AF_INET6)
710 				continue;
711 			if (!cmp)
712 				break;
713 			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
714 			candidate.s_addr &= mask.s_addr;
715 			if (candidate.s_addr == match.s_addr)
716 				break;
717 		}
718 		if (!ifa)
719 			return EADDRNOTAVAIL;
720 		ia = (struct in_ifaddr *)ifa;
721 
722 		if (cmd == SIOCGLIFADDR) {
723 			/* fill in the if_laddrreq structure */
724 			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
725 
726 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
727 				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
728 					ia->ia_dstaddr.sin_len);
729 			} else
730 				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
731 
732 			iflr->prefixlen =
733 				in_mask2len(&ia->ia_sockmask.sin_addr);
734 
735 			iflr->flags = 0;	/*XXX*/
736 
737 			return 0;
738 		} else {
739 			struct in_aliasreq ifra;
740 
741 			/* fill in_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
742 			bzero(&ifra, sizeof(ifra));
743 			bcopy(iflr->iflr_name, ifra.ifra_name,
744 				sizeof(ifra.ifra_name));
745 
746 			bcopy(&ia->ia_addr, &ifra.ifra_addr,
747 				ia->ia_addr.sin_len);
748 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
749 				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
750 					ia->ia_dstaddr.sin_len);
751 			}
752 			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
753 				ia->ia_sockmask.sin_len);
754 
755 			return in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
756 				ifp, p);
757 		}
758 	    }
759 	}
760 
761 	return EOPNOTSUPP;	/*just for safety*/
762 }
763 
764 /*
765  * Delete any existing route for an interface.
766  */
767 void
768 in_ifscrub(ifp, ia)
769 	struct ifnet *ifp;
770 	struct in_ifaddr *ia;
771 {
772 
773 	in_scrubprefix(ia);
774 }
775 
776 /*
777  * Initialize an interface's internet address
778  * and routing table entry.
779  */
780 int
781 in_ifinit(ifp, ia, sin, scrub)
782 	struct ifnet *ifp;
783 	struct in_ifaddr *ia;
784 	struct sockaddr_in *sin;
785 	int scrub;
786 {
787 	u_int32_t i = sin->sin_addr.s_addr;
788 	struct sockaddr_in oldaddr;
789 	int s = splnet(), flags = RTF_UP, error;
790 
791 	/*
792 	 * Set up new addresses.
793 	 */
794 	oldaddr = ia->ia_addr;
795 	if (ia->ia_addr.sin_family == AF_INET)
796 		LIST_REMOVE(ia, ia_hash);
797 	ia->ia_addr = *sin;
798 	LIST_INSERT_HEAD(&IN_IFADDR_HASH(ia->ia_addr.sin_addr.s_addr), ia, ia_hash);
799 
800 	/*
801 	 * Give the interface a chance to initialize
802 	 * if this is its first address,
803 	 * and to validate the address if necessary.
804 	 */
805 	if (ifp->if_ioctl &&
806 	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia)))
807 		goto bad;
808 	splx(s);
809 	if (scrub) {
810 		ia->ia_ifa.ifa_addr = sintosa(&oldaddr);
811 		in_ifscrub(ifp, ia);
812 		ia->ia_ifa.ifa_addr = sintosa(&ia->ia_addr);
813 	}
814 
815 	if (IN_CLASSA(i))
816 		ia->ia_netmask = IN_CLASSA_NET;
817 	else if (IN_CLASSB(i))
818 		ia->ia_netmask = IN_CLASSB_NET;
819 	else
820 		ia->ia_netmask = IN_CLASSC_NET;
821 	/*
822 	 * The subnet mask usually includes at least the standard network part,
823 	 * but may may be smaller in the case of supernetting.
824 	 * If it is set, we believe it.
825 	 */
826 	if (ia->ia_subnetmask == 0) {
827 		ia->ia_subnetmask = ia->ia_netmask;
828 		ia->ia_sockmask.sin_addr.s_addr = ia->ia_subnetmask;
829 	} else
830 		ia->ia_netmask &= ia->ia_subnetmask;
831 
832 	ia->ia_net = i & ia->ia_netmask;
833 	ia->ia_subnet = i & ia->ia_subnetmask;
834 	in_socktrim(&ia->ia_sockmask);
835 	/* re-calculate the "in_maxmtu" value */
836 	in_setmaxmtu();
837 	/*
838 	 * Add route for the network.
839 	 */
840 	ia->ia_ifa.ifa_metric = ifp->if_metric;
841 	if (ifp->if_flags & IFF_BROADCAST) {
842 		ia->ia_broadaddr.sin_addr.s_addr =
843 			ia->ia_subnet | ~ia->ia_subnetmask;
844 		ia->ia_netbroadcast.s_addr =
845 			ia->ia_net | ~ia->ia_netmask;
846 	} else if (ifp->if_flags & IFF_LOOPBACK) {
847 		ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
848 		flags |= RTF_HOST;
849 	} else if (ifp->if_flags & IFF_POINTOPOINT) {
850 		if (ia->ia_dstaddr.sin_family != AF_INET)
851 			return (0);
852 		flags |= RTF_HOST;
853 	}
854 	error = in_addprefix(ia, flags);
855 	/*
856 	 * recover multicast kludge entry, if there is.
857 	 */
858 	if (ifp->if_flags & IFF_MULTICAST)
859 		in_restoremkludge(ia, ifp);
860 	/*
861 	 * If the interface supports multicast, join the "all hosts"
862 	 * multicast group on that interface.
863 	 */
864 	if ((ifp->if_flags & IFF_MULTICAST) != 0 && ia->ia_allhosts == NULL) {
865 		struct in_addr addr;
866 
867 		addr.s_addr = INADDR_ALLHOSTS_GROUP;
868 		ia->ia_allhosts = in_addmulti(&addr, ifp);
869 	}
870 	return (error);
871 bad:
872 	splx(s);
873 	LIST_REMOVE(ia, ia_hash);
874 	ia->ia_addr = oldaddr;
875 	if (ia->ia_addr.sin_family == AF_INET)
876 		LIST_INSERT_HEAD(&IN_IFADDR_HASH(ia->ia_addr.sin_addr.s_addr),
877 		    ia, ia_hash);
878 	return (error);
879 }
880 
881 #define rtinitflags(x) \
882 	((((x)->ia_ifp->if_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) != 0) \
883 	    ? RTF_HOST : 0)
884 
885 /*
886  * add a route to prefix ("connected route" in cisco terminology).
887  * does nothing if there's some interface address with the same prefix already.
888  */
889 static int
890 in_addprefix(target, flags)
891 	struct in_ifaddr *target;
892 	int flags;
893 {
894 	struct in_ifaddr *ia;
895 	struct in_addr prefix, mask, p;
896 	int error;
897 
898 	if ((flags & RTF_HOST) != 0)
899 		prefix = target->ia_dstaddr.sin_addr;
900 	else
901 		prefix = target->ia_addr.sin_addr;
902 	mask = target->ia_sockmask.sin_addr;
903 	prefix.s_addr &= mask.s_addr;
904 
905 	for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) {
906 		/* easy one first */
907 		if (mask.s_addr != ia->ia_sockmask.sin_addr.s_addr)
908 			continue;
909 
910 		if (rtinitflags(ia))
911 			p = ia->ia_dstaddr.sin_addr;
912 		else
913 			p = ia->ia_addr.sin_addr;
914 		p.s_addr &= ia->ia_sockmask.sin_addr.s_addr;
915 		if (prefix.s_addr != p.s_addr)
916 			continue;
917 
918 		/*
919 		 * if we got a matching prefix route inserted by other
920 		 * interface adderss, we don't need to bother
921 		 */
922 		if (ia->ia_flags & IFA_ROUTE)
923 			return 0;
924 	}
925 
926 	/*
927 	 * noone seem to have prefix route.  insert it.
928 	 */
929 	error = rtinit(&target->ia_ifa, (int)RTM_ADD, flags);
930 	if (!error)
931 		target->ia_flags |= IFA_ROUTE;
932 	return error;
933 }
934 
935 /*
936  * remove a route to prefix ("connected route" in cisco terminology).
937  * re-installs the route by using another interface address, if there's one
938  * with the same prefix (otherwise we lose the route mistakenly).
939  */
940 static int
941 in_scrubprefix(target)
942 	struct in_ifaddr *target;
943 {
944 	struct in_ifaddr *ia;
945 	struct in_addr prefix, mask, p;
946 	int error;
947 
948 	if ((target->ia_flags & IFA_ROUTE) == 0)
949 		return 0;
950 
951 	if (rtinitflags(target))
952 		prefix = target->ia_dstaddr.sin_addr;
953 	else
954 		prefix = target->ia_addr.sin_addr;
955 	mask = target->ia_sockmask.sin_addr;
956 	prefix.s_addr &= mask.s_addr;
957 
958 	for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) {
959 		/* easy one first */
960 		if (mask.s_addr != ia->ia_sockmask.sin_addr.s_addr)
961 			continue;
962 
963 		if (rtinitflags(ia))
964 			p = ia->ia_dstaddr.sin_addr;
965 		else
966 			p = ia->ia_addr.sin_addr;
967 		p.s_addr &= ia->ia_sockmask.sin_addr.s_addr;
968 		if (prefix.s_addr != p.s_addr)
969 			continue;
970 
971 		/*
972 		 * if we got a matching prefix route, move IFA_ROUTE to him
973 		 */
974 		if ((ia->ia_flags & IFA_ROUTE) == 0) {
975 			rtinit(&(target->ia_ifa), (int)RTM_DELETE,
976 			    rtinitflags(target));
977 			target->ia_flags &= ~IFA_ROUTE;
978 
979 			error = rtinit(&ia->ia_ifa, (int)RTM_ADD,
980 			    rtinitflags(ia) | RTF_UP);
981 			if (error == 0)
982 				ia->ia_flags |= IFA_ROUTE;
983 			return error;
984 		}
985 	}
986 
987 	/*
988 	 * noone seem to have prefix route.  remove it.
989 	 */
990 	rtinit(&(target->ia_ifa), (int)RTM_DELETE, rtinitflags(target));
991 	target->ia_flags &= ~IFA_ROUTE;
992 	return 0;
993 }
994 
995 #undef rtinitflags
996 
997 /*
998  * Return 1 if the address might be a local broadcast address.
999  */
1000 int
1001 in_broadcast(in, ifp)
1002 	struct in_addr in;
1003 	struct ifnet *ifp;
1004 {
1005 	struct ifaddr *ifa;
1006 
1007 	if (in.s_addr == INADDR_BROADCAST ||
1008 	    in_nullhost(in))
1009 		return 1;
1010 	if ((ifp->if_flags & IFF_BROADCAST) == 0)
1011 		return 0;
1012 	/*
1013 	 * Look through the list of addresses for a match
1014 	 * with a broadcast address.
1015 	 */
1016 #define ia (ifatoia(ifa))
1017 	for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
1018 		if (ifa->ifa_addr->sa_family == AF_INET &&
1019 		    (in_hosteq(in, ia->ia_broadaddr.sin_addr) ||
1020 		     in_hosteq(in, ia->ia_netbroadcast) ||
1021 		     (hostzeroisbroadcast &&
1022 		      /*
1023 		       * Check for old-style (host 0) broadcast.
1024 		       */
1025 		      (in.s_addr == ia->ia_subnet ||
1026 		       in.s_addr == ia->ia_net))))
1027 			return 1;
1028 	return (0);
1029 #undef ia
1030 }
1031 
1032 /*
1033  * Multicast address kludge:
1034  * If there were any multicast addresses attached to this interface address,
1035  * either move them to another address on this interface, or save them until
1036  * such time as this interface is reconfigured for IPv4.
1037  */
1038 void
1039 in_savemkludge(oia)
1040 	struct in_ifaddr *oia;
1041 {
1042 	struct in_ifaddr *ia;
1043 	struct in_multi *inm, *next;
1044 
1045 	IFP_TO_IA(oia->ia_ifp, ia);
1046 	if (ia) {	/* there is another address */
1047 		for (inm = oia->ia_multiaddrs.lh_first; inm; inm = next){
1048 			next = inm->inm_list.le_next;
1049 			IFAFREE(&inm->inm_ia->ia_ifa);
1050 			IFAREF(&ia->ia_ifa);
1051 			inm->inm_ia = ia;
1052 			LIST_INSERT_HEAD(&ia->ia_multiaddrs, inm, inm_list);
1053 		}
1054 	} else {	/* last address on this if deleted, save */
1055 		TAILQ_INSERT_TAIL(&in_mk, oia, ia_list);
1056 		IFAREF(&oia->ia_ifa);
1057 	}
1058 }
1059 
1060 /*
1061  * Continuation of multicast address hack:
1062  * If there was a multicast group list previously saved for this interface,
1063  * then we re-attach it to the first address configured on the i/f.
1064  */
1065 void
1066 in_restoremkludge(ia, ifp)
1067 	struct in_ifaddr *ia;
1068 	struct ifnet *ifp;
1069 {
1070 	struct in_ifaddr *oia;
1071 
1072 	for (oia = TAILQ_FIRST(&in_mk); oia != NULL;
1073 	    oia = TAILQ_NEXT(oia, ia_list)) {
1074 		if (oia->ia_ifp == ifp) {
1075 			struct in_multi *inm, *next;
1076 
1077 			for (inm = LIST_FIRST(&oia->ia_multiaddrs);
1078 			    inm != NULL; inm = next) {
1079 				next = LIST_NEXT(inm, inm_list);
1080 				IFAFREE(&inm->inm_ia->ia_ifa);
1081 				IFAREF(&ia->ia_ifa);
1082 				inm->inm_ia = ia;
1083 				LIST_INSERT_HEAD(&ia->ia_multiaddrs,
1084 				    inm, inm_list);
1085 			}
1086 	    		TAILQ_REMOVE(&in_mk, oia, ia_list);
1087 			IFAFREE(&oia->ia_ifa);
1088 			break;
1089 		}
1090 	}
1091 }
1092 
1093 void
1094 in_purgemkludge(ifp)
1095 	struct ifnet *ifp;
1096 {
1097 	struct in_ifaddr *oia;
1098 
1099 	for (oia = TAILQ_FIRST(&in_mk); oia != NULL;
1100 	    oia = TAILQ_NEXT(oia, ia_list)) {
1101 		if (oia->ia_ifp != ifp)
1102 			continue;
1103 
1104 		/*
1105 		 * Leaving from all multicast groups joined through
1106 		 * this interface is done via in_pcbpurgeif().
1107 		 */
1108 
1109 	    	TAILQ_REMOVE(&in_mk, oia, ia_list);
1110 		IFAFREE(&oia->ia_ifa);
1111 		break;
1112 	}
1113 }
1114 
1115 /*
1116  * Add an address to the list of IP multicast addresses for a given interface.
1117  */
1118 struct in_multi *
1119 in_addmulti(ap, ifp)
1120 	struct in_addr *ap;
1121 	struct ifnet *ifp;
1122 {
1123 	struct in_multi *inm;
1124 	struct ifreq ifr;
1125 	struct in_ifaddr *ia;
1126 	int s = splsoftnet();
1127 
1128 	/*
1129 	 * See if address already in list.
1130 	 */
1131 	IN_LOOKUP_MULTI(*ap, ifp, inm);
1132 	if (inm != NULL) {
1133 		/*
1134 		 * Found it; just increment the reference count.
1135 		 */
1136 		++inm->inm_refcount;
1137 	} else {
1138 		/*
1139 		 * New address; allocate a new multicast record
1140 		 * and link it into the interface's multicast list.
1141 		 */
1142 		inm = (struct in_multi *)malloc(sizeof(*inm),
1143 		    M_IPMADDR, M_NOWAIT);
1144 		if (inm == NULL) {
1145 			splx(s);
1146 			return (NULL);
1147 		}
1148 		inm->inm_addr = *ap;
1149 		inm->inm_ifp = ifp;
1150 		inm->inm_refcount = 1;
1151 		IFP_TO_IA(ifp, ia);
1152 		if (ia == NULL) {
1153 			free(inm, M_IPMADDR);
1154 			splx(s);
1155 			return (NULL);
1156 		}
1157 		inm->inm_ia = ia;
1158 		IFAREF(&inm->inm_ia->ia_ifa);
1159 		LIST_INSERT_HEAD(&ia->ia_multiaddrs, inm, inm_list);
1160 		/*
1161 		 * Ask the network driver to update its multicast reception
1162 		 * filter appropriately for the new address.
1163 		 */
1164 		satosin(&ifr.ifr_addr)->sin_len = sizeof(struct sockaddr_in);
1165 		satosin(&ifr.ifr_addr)->sin_family = AF_INET;
1166 		satosin(&ifr.ifr_addr)->sin_addr = *ap;
1167 		if ((ifp->if_ioctl == NULL) ||
1168 		    (*ifp->if_ioctl)(ifp, SIOCADDMULTI,(caddr_t)&ifr) != 0) {
1169 			LIST_REMOVE(inm, inm_list);
1170 			free(inm, M_IPMADDR);
1171 			splx(s);
1172 			return (NULL);
1173 		}
1174 		/*
1175 		 * Let IGMP know that we have joined a new IP multicast group.
1176 		 */
1177 		igmp_joingroup(inm);
1178 	}
1179 	splx(s);
1180 	return (inm);
1181 }
1182 
1183 /*
1184  * Delete a multicast address record.
1185  */
1186 void
1187 in_delmulti(inm)
1188 	struct in_multi *inm;
1189 {
1190 	struct ifreq ifr;
1191 	int s = splsoftnet();
1192 
1193 	if (--inm->inm_refcount == 0) {
1194 		/*
1195 		 * No remaining claims to this record; let IGMP know that
1196 		 * we are leaving the multicast group.
1197 		 */
1198 		igmp_leavegroup(inm);
1199 		/*
1200 		 * Unlink from list.
1201 		 */
1202 		LIST_REMOVE(inm, inm_list);
1203 		IFAFREE(&inm->inm_ia->ia_ifa);
1204 		/*
1205 		 * Notify the network driver to update its multicast reception
1206 		 * filter.
1207 		 */
1208 		satosin(&ifr.ifr_addr)->sin_family = AF_INET;
1209 		satosin(&ifr.ifr_addr)->sin_addr = inm->inm_addr;
1210 		(*inm->inm_ifp->if_ioctl)(inm->inm_ifp, SIOCDELMULTI,
1211 							     (caddr_t)&ifr);
1212 		free(inm, M_IPMADDR);
1213 	}
1214 	splx(s);
1215 }
1216 #endif
1217