xref: /freebsd/sys/netinet/in.c (revision 9336e0699bda8a301cd2bfa37106b6ec5e32012e)
1 /*-
2  * Copyright (c) 1982, 1986, 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * Copyright (C) 2001 WIDE Project.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 4. Neither the name of the University nor the names of its contributors
15  *    may be used to endorse or promote products derived from this software
16  *    without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  *	@(#)in.c	8.4 (Berkeley) 1/9/95
31  */
32 
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include "opt_carp.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/sockio.h>
41 #include <sys/malloc.h>
42 #include <sys/priv.h>
43 #include <sys/socket.h>
44 #include <sys/kernel.h>
45 #include <sys/sysctl.h>
46 
47 #include <net/if.h>
48 #include <net/if_types.h>
49 #include <net/route.h>
50 
51 #include <netinet/in.h>
52 #include <netinet/in_var.h>
53 #include <netinet/in_pcb.h>
54 #include <netinet/ip_var.h>
55 
56 static int in_mask2len(struct in_addr *);
57 static void in_len2mask(struct in_addr *, int);
58 static int in_lifaddr_ioctl(struct socket *, u_long, caddr_t,
59 	struct ifnet *, struct thread *);
60 
61 static int	in_addprefix(struct in_ifaddr *, int);
62 static int	in_scrubprefix(struct in_ifaddr *);
63 static void	in_socktrim(struct sockaddr_in *);
64 static int	in_ifinit(struct ifnet *,
65 	    struct in_ifaddr *, struct sockaddr_in *, int);
66 static void	in_purgemaddrs(struct ifnet *);
67 
68 static int subnetsarelocal = 0;
69 SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW,
70 	&subnetsarelocal, 0, "Treat all subnets as directly connected");
71 static int sameprefixcarponly = 0;
72 SYSCTL_INT(_net_inet_ip, OID_AUTO, same_prefix_carp_only, CTLFLAG_RW,
73 	&sameprefixcarponly, 0,
74 	"Refuse to create same prefixes on different interfaces");
75 
76 extern struct inpcbinfo ripcbinfo;
77 extern struct inpcbinfo udbinfo;
78 
79 /*
80  * Return 1 if an internet address is for a ``local'' host
81  * (one to which we have a connection).  If subnetsarelocal
82  * is true, this includes other subnets of the local net.
83  * Otherwise, it includes only the directly-connected (sub)nets.
84  */
85 int
86 in_localaddr(struct in_addr in)
87 {
88 	register u_long i = ntohl(in.s_addr);
89 	register struct in_ifaddr *ia;
90 
91 	if (subnetsarelocal) {
92 		TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link)
93 			if ((i & ia->ia_netmask) == ia->ia_net)
94 				return (1);
95 	} else {
96 		TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link)
97 			if ((i & ia->ia_subnetmask) == ia->ia_subnet)
98 				return (1);
99 	}
100 	return (0);
101 }
102 
103 /*
104  * Return 1 if an internet address is for the local host and configured
105  * on one of its interfaces.
106  */
107 int
108 in_localip(struct in_addr in)
109 {
110 	struct in_ifaddr *ia;
111 
112 	LIST_FOREACH(ia, INADDR_HASH(in.s_addr), ia_hash) {
113 		if (IA_SIN(ia)->sin_addr.s_addr == in.s_addr)
114 			return 1;
115 	}
116 	return 0;
117 }
118 
119 /*
120  * Determine whether an IP address is in a reserved set of addresses
121  * that may not be forwarded, or whether datagrams to that destination
122  * may be forwarded.
123  */
124 int
125 in_canforward(struct in_addr in)
126 {
127 	register u_long i = ntohl(in.s_addr);
128 	register u_long net;
129 
130 	if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i) || IN_LINKLOCAL(i))
131 		return (0);
132 	if (IN_CLASSA(i)) {
133 		net = i & IN_CLASSA_NET;
134 		if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
135 			return (0);
136 	}
137 	return (1);
138 }
139 
140 /*
141  * Trim a mask in a sockaddr
142  */
143 static void
144 in_socktrim(struct sockaddr_in *ap)
145 {
146     register char *cplim = (char *) &ap->sin_addr;
147     register char *cp = (char *) (&ap->sin_addr + 1);
148 
149     ap->sin_len = 0;
150     while (--cp >= cplim)
151 	if (*cp) {
152 	    (ap)->sin_len = cp - (char *) (ap) + 1;
153 	    break;
154 	}
155 }
156 
157 static int
158 in_mask2len(mask)
159 	struct in_addr *mask;
160 {
161 	int x, y;
162 	u_char *p;
163 
164 	p = (u_char *)mask;
165 	for (x = 0; x < sizeof(*mask); x++) {
166 		if (p[x] != 0xff)
167 			break;
168 	}
169 	y = 0;
170 	if (x < sizeof(*mask)) {
171 		for (y = 0; y < 8; y++) {
172 			if ((p[x] & (0x80 >> y)) == 0)
173 				break;
174 		}
175 	}
176 	return x * 8 + y;
177 }
178 
179 static void
180 in_len2mask(struct in_addr *mask, int len)
181 {
182 	int i;
183 	u_char *p;
184 
185 	p = (u_char *)mask;
186 	bzero(mask, sizeof(*mask));
187 	for (i = 0; i < len / 8; i++)
188 		p[i] = 0xff;
189 	if (len % 8)
190 		p[i] = (0xff00 >> (len % 8)) & 0xff;
191 }
192 
193 /*
194  * Generic internet control operations (ioctl's).
195  * Ifp is 0 if not an interface-specific ioctl.
196  */
197 /* ARGSUSED */
198 int
199 in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
200     struct thread *td)
201 {
202 	register struct ifreq *ifr = (struct ifreq *)data;
203 	register struct in_ifaddr *ia = 0, *iap;
204 	register struct ifaddr *ifa;
205 	struct in_addr allhosts_addr;
206 	struct in_addr dst;
207 	struct in_ifaddr *oia;
208 	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
209 	struct sockaddr_in oldaddr;
210 	int error, hostIsNew, iaIsNew, maskIsNew, s;
211 	int iaIsFirst;
212 
213 	iaIsFirst = 0;
214 	iaIsNew = 0;
215 	allhosts_addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
216 
217 	switch (cmd) {
218 	case SIOCALIFADDR:
219 		if (td != NULL) {
220 			error = priv_check(td, PRIV_NET_ADDIFADDR);
221 			if (error)
222 				return (error);
223 		}
224 		if (!ifp)
225 			return EINVAL;
226 		return in_lifaddr_ioctl(so, cmd, data, ifp, td);
227 
228 	case SIOCDLIFADDR:
229 		if (td != NULL) {
230 			error = priv_check(td, PRIV_NET_DELIFADDR);
231 			if (error)
232 				return (error);
233 		}
234 		if (!ifp)
235 			return EINVAL;
236 		return in_lifaddr_ioctl(so, cmd, data, ifp, td);
237 
238 	case SIOCGLIFADDR:
239 		if (!ifp)
240 			return EINVAL;
241 		return in_lifaddr_ioctl(so, cmd, data, ifp, td);
242 	}
243 
244 	/*
245 	 * Find address for this interface, if it exists.
246 	 *
247 	 * If an alias address was specified, find that one instead of
248 	 * the first one on the interface, if possible.
249 	 */
250 	if (ifp) {
251 		dst = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
252 		LIST_FOREACH(iap, INADDR_HASH(dst.s_addr), ia_hash)
253 			if (iap->ia_ifp == ifp &&
254 			    iap->ia_addr.sin_addr.s_addr == dst.s_addr) {
255 				ia = iap;
256 				break;
257 			}
258 		if (ia == NULL)
259 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
260 				iap = ifatoia(ifa);
261 				if (iap->ia_addr.sin_family == AF_INET) {
262 					ia = iap;
263 					break;
264 				}
265 			}
266 		if (ia == NULL)
267 			iaIsFirst = 1;
268 	}
269 
270 	switch (cmd) {
271 
272 	case SIOCAIFADDR:
273 	case SIOCDIFADDR:
274 		if (ifp == 0)
275 			return (EADDRNOTAVAIL);
276 		if (ifra->ifra_addr.sin_family == AF_INET) {
277 			for (oia = ia; ia; ia = TAILQ_NEXT(ia, ia_link)) {
278 				if (ia->ia_ifp == ifp  &&
279 				    ia->ia_addr.sin_addr.s_addr ==
280 				    ifra->ifra_addr.sin_addr.s_addr)
281 					break;
282 			}
283 			if ((ifp->if_flags & IFF_POINTOPOINT)
284 			    && (cmd == SIOCAIFADDR)
285 			    && (ifra->ifra_dstaddr.sin_addr.s_addr
286 				== INADDR_ANY)) {
287 				return EDESTADDRREQ;
288 			}
289 		}
290 		if (cmd == SIOCDIFADDR && ia == 0)
291 			return (EADDRNOTAVAIL);
292 		/* FALLTHROUGH */
293 	case SIOCSIFADDR:
294 	case SIOCSIFNETMASK:
295 	case SIOCSIFDSTADDR:
296 		if (td != NULL) {
297 			error = priv_check(td, PRIV_NET_ADDIFADDR);
298 			if (error)
299 				return (error);
300 		}
301 
302 		if (ifp == 0)
303 			return (EADDRNOTAVAIL);
304 		if (ia == (struct in_ifaddr *)0) {
305 			ia = (struct in_ifaddr *)
306 				malloc(sizeof *ia, M_IFADDR, M_WAITOK | M_ZERO);
307 			if (ia == (struct in_ifaddr *)NULL)
308 				return (ENOBUFS);
309 			/*
310 			 * Protect from ipintr() traversing address list
311 			 * while we're modifying it.
312 			 */
313 			s = splnet();
314 			ifa = &ia->ia_ifa;
315 			IFA_LOCK_INIT(ifa);
316 			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
317 			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
318 			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
319 			ifa->ifa_refcnt = 1;
320 			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
321 
322 			ia->ia_sockmask.sin_len = 8;
323 			ia->ia_sockmask.sin_family = AF_INET;
324 			if (ifp->if_flags & IFF_BROADCAST) {
325 				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
326 				ia->ia_broadaddr.sin_family = AF_INET;
327 			}
328 			ia->ia_ifp = ifp;
329 
330 			TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
331 			splx(s);
332 			iaIsNew = 1;
333 		}
334 		break;
335 
336 	case SIOCSIFBRDADDR:
337 		if (td != NULL) {
338 			error = priv_check(td, PRIV_NET_ADDIFADDR);
339 			if (error)
340 				return (error);
341 		}
342 		/* FALLTHROUGH */
343 
344 	case SIOCGIFADDR:
345 	case SIOCGIFNETMASK:
346 	case SIOCGIFDSTADDR:
347 	case SIOCGIFBRDADDR:
348 		if (ia == (struct in_ifaddr *)0)
349 			return (EADDRNOTAVAIL);
350 		break;
351 	}
352 	switch (cmd) {
353 
354 	case SIOCGIFADDR:
355 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
356 		return (0);
357 
358 	case SIOCGIFBRDADDR:
359 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
360 			return (EINVAL);
361 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
362 		return (0);
363 
364 	case SIOCGIFDSTADDR:
365 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
366 			return (EINVAL);
367 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
368 		return (0);
369 
370 	case SIOCGIFNETMASK:
371 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
372 		return (0);
373 
374 	case SIOCSIFDSTADDR:
375 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
376 			return (EINVAL);
377 		oldaddr = ia->ia_dstaddr;
378 		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
379 		if (ifp->if_ioctl) {
380 			IFF_LOCKGIANT(ifp);
381 			error = (*ifp->if_ioctl)(ifp, SIOCSIFDSTADDR,
382 			    (caddr_t)ia);
383 			IFF_UNLOCKGIANT(ifp);
384 			if (error) {
385 				ia->ia_dstaddr = oldaddr;
386 				return (error);
387 			}
388 		}
389 		if (ia->ia_flags & IFA_ROUTE) {
390 			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
391 			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
392 			ia->ia_ifa.ifa_dstaddr =
393 					(struct sockaddr *)&ia->ia_dstaddr;
394 			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
395 		}
396 		return (0);
397 
398 	case SIOCSIFBRDADDR:
399 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
400 			return (EINVAL);
401 		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
402 		return (0);
403 
404 	case SIOCSIFADDR:
405 		error = in_ifinit(ifp, ia,
406 		    (struct sockaddr_in *) &ifr->ifr_addr, 1);
407 		if (error != 0 && iaIsNew)
408 			break;
409 		if (error == 0) {
410 			if (iaIsFirst && (ifp->if_flags & IFF_MULTICAST) != 0)
411 				in_addmulti(&allhosts_addr, ifp);
412 			EVENTHANDLER_INVOKE(ifaddr_event, ifp);
413 		}
414 		return (0);
415 
416 	case SIOCSIFNETMASK:
417 		ia->ia_sockmask.sin_addr = ifra->ifra_addr.sin_addr;
418 		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr);
419 		return (0);
420 
421 	case SIOCAIFADDR:
422 		maskIsNew = 0;
423 		hostIsNew = 1;
424 		error = 0;
425 		if (ia->ia_addr.sin_family == AF_INET) {
426 			if (ifra->ifra_addr.sin_len == 0) {
427 				ifra->ifra_addr = ia->ia_addr;
428 				hostIsNew = 0;
429 			} else if (ifra->ifra_addr.sin_addr.s_addr ==
430 					       ia->ia_addr.sin_addr.s_addr)
431 				hostIsNew = 0;
432 		}
433 		if (ifra->ifra_mask.sin_len) {
434 			in_ifscrub(ifp, ia);
435 			ia->ia_sockmask = ifra->ifra_mask;
436 			ia->ia_sockmask.sin_family = AF_INET;
437 			ia->ia_subnetmask =
438 			     ntohl(ia->ia_sockmask.sin_addr.s_addr);
439 			maskIsNew = 1;
440 		}
441 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
442 		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
443 			in_ifscrub(ifp, ia);
444 			ia->ia_dstaddr = ifra->ifra_dstaddr;
445 			maskIsNew  = 1; /* We lie; but the effect's the same */
446 		}
447 		if (ifra->ifra_addr.sin_family == AF_INET &&
448 		    (hostIsNew || maskIsNew))
449 			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
450 		if (error != 0 && iaIsNew)
451 			break;
452 
453 		if ((ifp->if_flags & IFF_BROADCAST) &&
454 		    (ifra->ifra_broadaddr.sin_family == AF_INET))
455 			ia->ia_broadaddr = ifra->ifra_broadaddr;
456 		if (error == 0) {
457 			if (iaIsFirst && (ifp->if_flags & IFF_MULTICAST) != 0)
458 				in_addmulti(&allhosts_addr, ifp);
459 			EVENTHANDLER_INVOKE(ifaddr_event, ifp);
460 		}
461 		return (error);
462 
463 	case SIOCDIFADDR:
464 		/*
465 		 * in_ifscrub kills the interface route.
466 		 */
467 		in_ifscrub(ifp, ia);
468 		/*
469 		 * in_ifadown gets rid of all the rest of
470 		 * the routes.  This is not quite the right
471 		 * thing to do, but at least if we are running
472 		 * a routing process they will come back.
473 		 */
474 		in_ifadown(&ia->ia_ifa, 1);
475 		EVENTHANDLER_INVOKE(ifaddr_event, ifp);
476 		error = 0;
477 		break;
478 
479 	default:
480 		if (ifp == 0 || ifp->if_ioctl == 0)
481 			return (EOPNOTSUPP);
482 		IFF_LOCKGIANT(ifp);
483 		error = (*ifp->if_ioctl)(ifp, cmd, data);
484 		IFF_UNLOCKGIANT(ifp);
485 		return (error);
486 	}
487 
488 	/*
489 	 * Protect from ipintr() traversing address list while we're modifying
490 	 * it.
491 	 */
492 	s = splnet();
493 	TAILQ_REMOVE(&ifp->if_addrhead, &ia->ia_ifa, ifa_link);
494 	TAILQ_REMOVE(&in_ifaddrhead, ia, ia_link);
495 	if (ia->ia_addr.sin_family == AF_INET) {
496 		LIST_REMOVE(ia, ia_hash);
497 		/*
498 		 * If this is the last IPv4 address configured on this
499 		 * interface, leave the all-hosts group.
500 		 * XXX: This is quite ugly because of locking and structure.
501 		 */
502 		oia = NULL;
503 		IFP_TO_IA(ifp, oia);
504 		if (oia == NULL) {
505 			struct in_multi *inm;
506 
507 			IFF_LOCKGIANT(ifp);
508 			IN_MULTI_LOCK();
509 			IN_LOOKUP_MULTI(allhosts_addr, ifp, inm);
510 			if (inm != NULL)
511 				in_delmulti_locked(inm);
512 			IN_MULTI_UNLOCK();
513 			IFF_UNLOCKGIANT(ifp);
514 		}
515 	}
516 	IFAFREE(&ia->ia_ifa);
517 	splx(s);
518 
519 	return (error);
520 }
521 
522 /*
523  * SIOC[GAD]LIFADDR.
524  *	SIOCGLIFADDR: get first address. (?!?)
525  *	SIOCGLIFADDR with IFLR_PREFIX:
526  *		get first address that matches the specified prefix.
527  *	SIOCALIFADDR: add the specified address.
528  *	SIOCALIFADDR with IFLR_PREFIX:
529  *		EINVAL since we can't deduce hostid part of the address.
530  *	SIOCDLIFADDR: delete the specified address.
531  *	SIOCDLIFADDR with IFLR_PREFIX:
532  *		delete the first address that matches the specified prefix.
533  * return values:
534  *	EINVAL on invalid parameters
535  *	EADDRNOTAVAIL on prefix match failed/specified address not found
536  *	other values may be returned from in_ioctl()
537  */
538 static int
539 in_lifaddr_ioctl(struct socket *so, u_long cmd, caddr_t data,
540     struct ifnet *ifp, struct thread *td)
541 {
542 	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
543 	struct ifaddr *ifa;
544 
545 	/* sanity checks */
546 	if (!data || !ifp) {
547 		panic("invalid argument to in_lifaddr_ioctl");
548 		/*NOTRECHED*/
549 	}
550 
551 	switch (cmd) {
552 	case SIOCGLIFADDR:
553 		/* address must be specified on GET with IFLR_PREFIX */
554 		if ((iflr->flags & IFLR_PREFIX) == 0)
555 			break;
556 		/*FALLTHROUGH*/
557 	case SIOCALIFADDR:
558 	case SIOCDLIFADDR:
559 		/* address must be specified on ADD and DELETE */
560 		if (iflr->addr.ss_family != AF_INET)
561 			return EINVAL;
562 		if (iflr->addr.ss_len != sizeof(struct sockaddr_in))
563 			return EINVAL;
564 		/* XXX need improvement */
565 		if (iflr->dstaddr.ss_family
566 		 && iflr->dstaddr.ss_family != AF_INET)
567 			return EINVAL;
568 		if (iflr->dstaddr.ss_family
569 		 && iflr->dstaddr.ss_len != sizeof(struct sockaddr_in))
570 			return EINVAL;
571 		break;
572 	default: /*shouldn't happen*/
573 		return EOPNOTSUPP;
574 	}
575 	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
576 		return EINVAL;
577 
578 	switch (cmd) {
579 	case SIOCALIFADDR:
580 	    {
581 		struct in_aliasreq ifra;
582 
583 		if (iflr->flags & IFLR_PREFIX)
584 			return EINVAL;
585 
586 		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
587 		bzero(&ifra, sizeof(ifra));
588 		bcopy(iflr->iflr_name, ifra.ifra_name,
589 			sizeof(ifra.ifra_name));
590 
591 		bcopy(&iflr->addr, &ifra.ifra_addr, iflr->addr.ss_len);
592 
593 		if (iflr->dstaddr.ss_family) {	/*XXX*/
594 			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
595 				iflr->dstaddr.ss_len);
596 		}
597 
598 		ifra.ifra_mask.sin_family = AF_INET;
599 		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
600 		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
601 
602 		return in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, td);
603 	    }
604 	case SIOCGLIFADDR:
605 	case SIOCDLIFADDR:
606 	    {
607 		struct in_ifaddr *ia;
608 		struct in_addr mask, candidate, match;
609 		struct sockaddr_in *sin;
610 
611 		bzero(&mask, sizeof(mask));
612 		bzero(&match, sizeof(match));
613 		if (iflr->flags & IFLR_PREFIX) {
614 			/* lookup a prefix rather than address. */
615 			in_len2mask(&mask, iflr->prefixlen);
616 
617 			sin = (struct sockaddr_in *)&iflr->addr;
618 			match.s_addr = sin->sin_addr.s_addr;
619 			match.s_addr &= mask.s_addr;
620 
621 			/* if you set extra bits, that's wrong */
622 			if (match.s_addr != sin->sin_addr.s_addr)
623 				return EINVAL;
624 
625 		} else {
626 			/* on getting an address, take the 1st match */
627 			/* on deleting an address, do exact match */
628 			if (cmd != SIOCGLIFADDR) {
629 				in_len2mask(&mask, 32);
630 				sin = (struct sockaddr_in *)&iflr->addr;
631 				match.s_addr = sin->sin_addr.s_addr;
632 			}
633 		}
634 
635 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)	{
636 			if (ifa->ifa_addr->sa_family != AF_INET6)
637 				continue;
638 			if (match.s_addr == 0)
639 				break;
640 			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
641 			candidate.s_addr &= mask.s_addr;
642 			if (candidate.s_addr == match.s_addr)
643 				break;
644 		}
645 		if (!ifa)
646 			return EADDRNOTAVAIL;
647 		ia = (struct in_ifaddr *)ifa;
648 
649 		if (cmd == SIOCGLIFADDR) {
650 			/* fill in the if_laddrreq structure */
651 			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
652 
653 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
654 				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
655 					ia->ia_dstaddr.sin_len);
656 			} else
657 				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
658 
659 			iflr->prefixlen =
660 				in_mask2len(&ia->ia_sockmask.sin_addr);
661 
662 			iflr->flags = 0;	/*XXX*/
663 
664 			return 0;
665 		} else {
666 			struct in_aliasreq ifra;
667 
668 			/* fill in_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
669 			bzero(&ifra, sizeof(ifra));
670 			bcopy(iflr->iflr_name, ifra.ifra_name,
671 				sizeof(ifra.ifra_name));
672 
673 			bcopy(&ia->ia_addr, &ifra.ifra_addr,
674 				ia->ia_addr.sin_len);
675 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
676 				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
677 					ia->ia_dstaddr.sin_len);
678 			}
679 			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
680 				ia->ia_sockmask.sin_len);
681 
682 			return in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
683 					  ifp, td);
684 		}
685 	    }
686 	}
687 
688 	return EOPNOTSUPP;	/*just for safety*/
689 }
690 
691 /*
692  * Delete any existing route for an interface.
693  */
694 void
695 in_ifscrub(struct ifnet *ifp, struct in_ifaddr *ia)
696 {
697 
698 	in_scrubprefix(ia);
699 }
700 
701 /*
702  * Initialize an interface's internet address
703  * and routing table entry.
704  */
705 static int
706 in_ifinit(struct ifnet *ifp, struct in_ifaddr *ia, struct sockaddr_in *sin,
707     int scrub)
708 {
709 	register u_long i = ntohl(sin->sin_addr.s_addr);
710 	struct sockaddr_in oldaddr;
711 	int s = splimp(), flags = RTF_UP, error = 0;
712 
713 	oldaddr = ia->ia_addr;
714 	if (oldaddr.sin_family == AF_INET)
715 		LIST_REMOVE(ia, ia_hash);
716 	ia->ia_addr = *sin;
717 	if (ia->ia_addr.sin_family == AF_INET)
718 		LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
719 		    ia, ia_hash);
720 	/*
721 	 * Give the interface a chance to initialize
722 	 * if this is its first address,
723 	 * and to validate the address if necessary.
724 	 */
725 	if (ifp->if_ioctl) {
726 		IFF_LOCKGIANT(ifp);
727 		error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia);
728 		IFF_UNLOCKGIANT(ifp);
729 		if (error) {
730 			splx(s);
731 			/* LIST_REMOVE(ia, ia_hash) is done in in_control */
732 			ia->ia_addr = oldaddr;
733 			if (ia->ia_addr.sin_family == AF_INET)
734 				LIST_INSERT_HEAD(INADDR_HASH(
735 				    ia->ia_addr.sin_addr.s_addr), ia, ia_hash);
736 			return (error);
737 		}
738 	}
739 	splx(s);
740 	if (scrub) {
741 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
742 		in_ifscrub(ifp, ia);
743 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
744 	}
745 	if (IN_CLASSA(i))
746 		ia->ia_netmask = IN_CLASSA_NET;
747 	else if (IN_CLASSB(i))
748 		ia->ia_netmask = IN_CLASSB_NET;
749 	else
750 		ia->ia_netmask = IN_CLASSC_NET;
751 	/*
752 	 * The subnet mask usually includes at least the standard network part,
753 	 * but may may be smaller in the case of supernetting.
754 	 * If it is set, we believe it.
755 	 */
756 	if (ia->ia_subnetmask == 0) {
757 		ia->ia_subnetmask = ia->ia_netmask;
758 		ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
759 	} else
760 		ia->ia_netmask &= ia->ia_subnetmask;
761 	ia->ia_net = i & ia->ia_netmask;
762 	ia->ia_subnet = i & ia->ia_subnetmask;
763 	in_socktrim(&ia->ia_sockmask);
764 #ifdef DEV_CARP
765 	/*
766 	 * XXX: carp(4) does not have interface route
767 	 */
768 	if (ifp->if_type == IFT_CARP)
769 		return (0);
770 #endif
771 	/*
772 	 * Add route for the network.
773 	 */
774 	ia->ia_ifa.ifa_metric = ifp->if_metric;
775 	if (ifp->if_flags & IFF_BROADCAST) {
776 		ia->ia_broadaddr.sin_addr.s_addr =
777 			htonl(ia->ia_subnet | ~ia->ia_subnetmask);
778 		ia->ia_netbroadcast.s_addr =
779 			htonl(ia->ia_net | ~ ia->ia_netmask);
780 	} else if (ifp->if_flags & IFF_LOOPBACK) {
781 		ia->ia_dstaddr = ia->ia_addr;
782 		flags |= RTF_HOST;
783 	} else if (ifp->if_flags & IFF_POINTOPOINT) {
784 		if (ia->ia_dstaddr.sin_family != AF_INET)
785 			return (0);
786 		flags |= RTF_HOST;
787 	}
788 	if ((error = in_addprefix(ia, flags)) != 0)
789 		return (error);
790 
791 	return (error);
792 }
793 
794 #define rtinitflags(x) \
795 	((((x)->ia_ifp->if_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) != 0) \
796 	    ? RTF_HOST : 0)
797 /*
798  * Check if we have a route for the given prefix already or add one accordingly.
799  */
800 static int
801 in_addprefix(struct in_ifaddr *target, int flags)
802 {
803 	struct in_ifaddr *ia;
804 	struct in_addr prefix, mask, p, m;
805 	int error;
806 
807 	if ((flags & RTF_HOST) != 0) {
808 		prefix = target->ia_dstaddr.sin_addr;
809 		mask.s_addr = 0;
810 	} else {
811 		prefix = target->ia_addr.sin_addr;
812 		mask = target->ia_sockmask.sin_addr;
813 		prefix.s_addr &= mask.s_addr;
814 	}
815 
816 	TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link) {
817 		if (rtinitflags(ia)) {
818 			p = ia->ia_addr.sin_addr;
819 
820 			if (prefix.s_addr != p.s_addr)
821 				continue;
822 		} else {
823 			p = ia->ia_addr.sin_addr;
824 			m = ia->ia_sockmask.sin_addr;
825 			p.s_addr &= m.s_addr;
826 
827 			if (prefix.s_addr != p.s_addr ||
828 			    mask.s_addr != m.s_addr)
829 				continue;
830 		}
831 
832 		/*
833 		 * If we got a matching prefix route inserted by other
834 		 * interface address, we are done here.
835 		 */
836 		if (ia->ia_flags & IFA_ROUTE) {
837 			if (sameprefixcarponly &&
838 			    target->ia_ifp->if_type != IFT_CARP &&
839 			    ia->ia_ifp->if_type != IFT_CARP)
840 				return (EEXIST);
841 			else
842 				return (0);
843 		}
844 	}
845 
846 	/*
847 	 * No-one seem to have this prefix route, so we try to insert it.
848 	 */
849 	error = rtinit(&target->ia_ifa, (int)RTM_ADD, flags);
850 	if (!error)
851 		target->ia_flags |= IFA_ROUTE;
852 	return error;
853 }
854 
855 /*
856  * If there is no other address in the system that can serve a route to the
857  * same prefix, remove the route.  Hand over the route to the new address
858  * otherwise.
859  */
860 static int
861 in_scrubprefix(struct in_ifaddr *target)
862 {
863 	struct in_ifaddr *ia;
864 	struct in_addr prefix, mask, p;
865 	int error;
866 
867 	if ((target->ia_flags & IFA_ROUTE) == 0)
868 		return 0;
869 
870 	if (rtinitflags(target))
871 		prefix = target->ia_dstaddr.sin_addr;
872 	else {
873 		prefix = target->ia_addr.sin_addr;
874 		mask = target->ia_sockmask.sin_addr;
875 		prefix.s_addr &= mask.s_addr;
876 	}
877 
878 	TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link) {
879 		if (rtinitflags(ia))
880 			p = ia->ia_dstaddr.sin_addr;
881 		else {
882 			p = ia->ia_addr.sin_addr;
883 			p.s_addr &= ia->ia_sockmask.sin_addr.s_addr;
884 		}
885 
886 		if (prefix.s_addr != p.s_addr)
887 			continue;
888 
889 		/*
890 		 * If we got a matching prefix address, move IFA_ROUTE and
891 		 * the route itself to it.  Make sure that routing daemons
892 		 * get a heads-up.
893 		 *
894 		 * XXX: a special case for carp(4) interface
895 		 */
896 		if ((ia->ia_flags & IFA_ROUTE) == 0
897 #ifdef DEV_CARP
898 		    && (ia->ia_ifp->if_type != IFT_CARP)
899 #endif
900 							) {
901 			rtinit(&(target->ia_ifa), (int)RTM_DELETE,
902 			    rtinitflags(target));
903 			target->ia_flags &= ~IFA_ROUTE;
904 
905 			error = rtinit(&ia->ia_ifa, (int)RTM_ADD,
906 			    rtinitflags(ia) | RTF_UP);
907 			if (error == 0)
908 				ia->ia_flags |= IFA_ROUTE;
909 			return error;
910 		}
911 	}
912 
913 	/*
914 	 * As no-one seem to have this prefix, we can remove the route.
915 	 */
916 	rtinit(&(target->ia_ifa), (int)RTM_DELETE, rtinitflags(target));
917 	target->ia_flags &= ~IFA_ROUTE;
918 	return 0;
919 }
920 
921 #undef rtinitflags
922 
923 /*
924  * Return 1 if the address might be a local broadcast address.
925  */
926 int
927 in_broadcast(struct in_addr in, struct ifnet *ifp)
928 {
929 	register struct ifaddr *ifa;
930 	u_long t;
931 
932 	if (in.s_addr == INADDR_BROADCAST ||
933 	    in.s_addr == INADDR_ANY)
934 		return 1;
935 	if ((ifp->if_flags & IFF_BROADCAST) == 0)
936 		return 0;
937 	t = ntohl(in.s_addr);
938 	/*
939 	 * Look through the list of addresses for a match
940 	 * with a broadcast address.
941 	 */
942 #define ia ((struct in_ifaddr *)ifa)
943 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
944 		if (ifa->ifa_addr->sa_family == AF_INET &&
945 		    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
946 		     in.s_addr == ia->ia_netbroadcast.s_addr ||
947 		     /*
948 		      * Check for old-style (host 0) broadcast.
949 		      */
950 		     t == ia->ia_subnet || t == ia->ia_net) &&
951 		     /*
952 		      * Check for an all one subnetmask. These
953 		      * only exist when an interface gets a secondary
954 		      * address.
955 		      */
956 		     ia->ia_subnetmask != (u_long)0xffffffff)
957 			    return 1;
958 	return (0);
959 #undef ia
960 }
961 
962 /*
963  * Delete all IPv4 multicast address records, and associated link-layer
964  * multicast address records, associated with ifp.
965  */
966 static void
967 in_purgemaddrs(struct ifnet *ifp)
968 {
969 	struct in_multi *inm;
970 	struct in_multi *oinm;
971 
972 #ifdef DIAGNOSTIC
973 	printf("%s: purging ifp %p\n", __func__, ifp);
974 #endif
975 	IFF_LOCKGIANT(ifp);
976 	IN_MULTI_LOCK();
977 	LIST_FOREACH_SAFE(inm, &in_multihead, inm_link, oinm) {
978 		if (inm->inm_ifp == ifp)
979 			in_delmulti_locked(inm);
980 	}
981 	IN_MULTI_UNLOCK();
982 	IFF_UNLOCKGIANT(ifp);
983 }
984 
985 /*
986  * On interface removal, clean up IPv4 data structures hung off of the ifnet.
987  */
988 void
989 in_ifdetach(struct ifnet *ifp)
990 {
991 
992 	in_pcbpurgeif0(&ripcbinfo, ifp);
993 	in_pcbpurgeif0(&udbinfo, ifp);
994 	in_purgemaddrs(ifp);
995 }
996