xref: /freebsd/sys/netinet/in.c (revision 0f8f86b71f022b803e99151c19db81b280f245dc)
1 /*
2  * Copyright (c) 1982, 1986, 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)in.c	8.4 (Berkeley) 1/9/95
34  * $FreeBSD$
35  */
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/sockio.h>
40 #include <sys/malloc.h>
41 #include <sys/socket.h>
42 #include <sys/kernel.h>
43 #include <sys/sysctl.h>
44 
45 #include <net/if.h>
46 #include <net/if_types.h>
47 #include <net/route.h>
48 
49 #include <netinet/in.h>
50 #include <netinet/in_var.h>
51 #include <netinet/in_pcb.h>
52 
53 #include <netinet/igmp_var.h>
54 
55 static MALLOC_DEFINE(M_IPMADDR, "in_multi", "internet multicast address");
56 
57 static int in_mask2len(struct in_addr *);
58 static void in_len2mask(struct in_addr *, int);
59 static int in_lifaddr_ioctl(struct socket *, u_long, caddr_t,
60 	struct ifnet *, struct thread *);
61 
62 static void	in_socktrim(struct sockaddr_in *);
63 static int	in_ifinit(struct ifnet *,
64 	    struct in_ifaddr *, struct sockaddr_in *, int);
65 
66 static int subnetsarelocal = 0;
67 SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW,
68 	&subnetsarelocal, 0, "Treat all subnets as directly connected");
69 
70 struct in_multihead in_multihead; /* XXX BSS initialization */
71 
72 extern struct inpcbinfo ripcbinfo;
73 extern struct inpcbinfo udbinfo;
74 
75 /*
76  * Return 1 if an internet address is for a ``local'' host
77  * (one to which we have a connection).  If subnetsarelocal
78  * is true, this includes other subnets of the local net.
79  * Otherwise, it includes only the directly-connected (sub)nets.
80  */
81 int
82 in_localaddr(in)
83 	struct in_addr in;
84 {
85 	register u_long i = ntohl(in.s_addr);
86 	register struct in_ifaddr *ia;
87 
88 	if (subnetsarelocal) {
89 		TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link)
90 			if ((i & ia->ia_netmask) == ia->ia_net)
91 				return (1);
92 	} else {
93 		TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link)
94 			if ((i & ia->ia_subnetmask) == ia->ia_subnet)
95 				return (1);
96 	}
97 	return (0);
98 }
99 
100 /*
101  * Determine whether an IP address is in a reserved set of addresses
102  * that may not be forwarded, or whether datagrams to that destination
103  * may be forwarded.
104  */
105 int
106 in_canforward(in)
107 	struct in_addr in;
108 {
109 	register u_long i = ntohl(in.s_addr);
110 	register u_long net;
111 
112 	if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i))
113 		return (0);
114 	if (IN_CLASSA(i)) {
115 		net = i & IN_CLASSA_NET;
116 		if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
117 			return (0);
118 	}
119 	return (1);
120 }
121 
122 /*
123  * Trim a mask in a sockaddr
124  */
125 static void
126 in_socktrim(ap)
127 struct sockaddr_in *ap;
128 {
129     register char *cplim = (char *) &ap->sin_addr;
130     register char *cp = (char *) (&ap->sin_addr + 1);
131 
132     ap->sin_len = 0;
133     while (--cp >= cplim)
134         if (*cp) {
135 	    (ap)->sin_len = cp - (char *) (ap) + 1;
136 	    break;
137 	}
138 }
139 
140 static int
141 in_mask2len(mask)
142 	struct in_addr *mask;
143 {
144 	int x, y;
145 	u_char *p;
146 
147 	p = (u_char *)mask;
148 	for (x = 0; x < sizeof(*mask); x++) {
149 		if (p[x] != 0xff)
150 			break;
151 	}
152 	y = 0;
153 	if (x < sizeof(*mask)) {
154 		for (y = 0; y < 8; y++) {
155 			if ((p[x] & (0x80 >> y)) == 0)
156 				break;
157 		}
158 	}
159 	return x * 8 + y;
160 }
161 
162 static void
163 in_len2mask(mask, len)
164 	struct in_addr *mask;
165 	int len;
166 {
167 	int i;
168 	u_char *p;
169 
170 	p = (u_char *)mask;
171 	bzero(mask, sizeof(*mask));
172 	for (i = 0; i < len / 8; i++)
173 		p[i] = 0xff;
174 	if (len % 8)
175 		p[i] = (0xff00 >> (len % 8)) & 0xff;
176 }
177 
178 /*
179  * Generic internet control operations (ioctl's).
180  * Ifp is 0 if not an interface-specific ioctl.
181  */
182 /* ARGSUSED */
183 int
184 in_control(so, cmd, data, ifp, td)
185 	struct socket *so;
186 	u_long cmd;
187 	caddr_t data;
188 	register struct ifnet *ifp;
189 	struct thread *td;
190 {
191 	register struct ifreq *ifr = (struct ifreq *)data;
192 	register struct in_ifaddr *ia = 0, *iap;
193 	register struct ifaddr *ifa;
194 	struct in_addr dst;
195 	struct in_ifaddr *oia;
196 	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
197 	struct sockaddr_in oldaddr;
198 	int error, hostIsNew, iaIsNew, maskIsNew, s;
199 
200 	iaIsNew = 0;
201 
202 	switch (cmd) {
203 	case SIOCALIFADDR:
204 	case SIOCDLIFADDR:
205 		if (td && (error = suser(td)) != 0)
206 			return error;
207 		/*fall through*/
208 	case SIOCGLIFADDR:
209 		if (!ifp)
210 			return EINVAL;
211 		return in_lifaddr_ioctl(so, cmd, data, ifp, td);
212 	}
213 
214 	/*
215 	 * Find address for this interface, if it exists.
216 	 *
217 	 * If an alias address was specified, find that one instead of
218 	 * the first one on the interface, if possible.
219 	 */
220 	if (ifp) {
221 		dst = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
222 		LIST_FOREACH(iap, INADDR_HASH(dst.s_addr), ia_hash)
223 			if (iap->ia_ifp == ifp &&
224 			    iap->ia_addr.sin_addr.s_addr == dst.s_addr) {
225 				ia = iap;
226 				break;
227 			}
228 		if (ia == NULL)
229 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
230 				iap = ifatoia(ifa);
231 				if (iap->ia_addr.sin_family == AF_INET) {
232 					ia = iap;
233 					break;
234 				}
235 			}
236 	}
237 
238 	switch (cmd) {
239 
240 	case SIOCAIFADDR:
241 	case SIOCDIFADDR:
242 		if (ifp == 0)
243 			return (EADDRNOTAVAIL);
244 		if (ifra->ifra_addr.sin_family == AF_INET) {
245 			for (oia = ia; ia; ia = TAILQ_NEXT(ia, ia_link)) {
246 				if (ia->ia_ifp == ifp  &&
247 				    ia->ia_addr.sin_addr.s_addr ==
248 				    ifra->ifra_addr.sin_addr.s_addr)
249 					break;
250 			}
251 			if ((ifp->if_flags & IFF_POINTOPOINT)
252 			    && (cmd == SIOCAIFADDR)
253 			    && (ifra->ifra_dstaddr.sin_addr.s_addr
254 				== INADDR_ANY)) {
255 				return EDESTADDRREQ;
256 			}
257 		}
258 		if (cmd == SIOCDIFADDR && ia == 0)
259 			return (EADDRNOTAVAIL);
260 		/* FALLTHROUGH */
261 	case SIOCSIFADDR:
262 	case SIOCSIFNETMASK:
263 	case SIOCSIFDSTADDR:
264 		if (td && (error = suser(td)) != 0)
265 			return error;
266 
267 		if (ifp == 0)
268 			return (EADDRNOTAVAIL);
269 		if (ia == (struct in_ifaddr *)0) {
270 			ia = (struct in_ifaddr *)
271 				malloc(sizeof *ia, M_IFADDR, M_WAITOK | M_ZERO);
272 			if (ia == (struct in_ifaddr *)NULL)
273 				return (ENOBUFS);
274 			/*
275 			 * Protect from ipintr() traversing address list
276 			 * while we're modifying it.
277 			 */
278 			s = splnet();
279 			TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
280 
281 			ifa = &ia->ia_ifa;
282 			IFA_LOCK_INIT(ifa);
283 			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
284 			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
285 			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
286 			ifa->ifa_refcnt = 1;
287 			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
288 
289 			ia->ia_sockmask.sin_len = 8;
290 			ia->ia_sockmask.sin_family = AF_INET;
291 			if (ifp->if_flags & IFF_BROADCAST) {
292 				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
293 				ia->ia_broadaddr.sin_family = AF_INET;
294 			}
295 			ia->ia_ifp = ifp;
296 			splx(s);
297 			iaIsNew = 1;
298 		}
299 		break;
300 
301 	case SIOCSIFBRDADDR:
302 		if (td && (error = suser(td)) != 0)
303 			return error;
304 		/* FALLTHROUGH */
305 
306 	case SIOCGIFADDR:
307 	case SIOCGIFNETMASK:
308 	case SIOCGIFDSTADDR:
309 	case SIOCGIFBRDADDR:
310 		if (ia == (struct in_ifaddr *)0)
311 			return (EADDRNOTAVAIL);
312 		break;
313 	}
314 	switch (cmd) {
315 
316 	case SIOCGIFADDR:
317 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
318 		return (0);
319 
320 	case SIOCGIFBRDADDR:
321 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
322 			return (EINVAL);
323 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
324 		return (0);
325 
326 	case SIOCGIFDSTADDR:
327 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
328 			return (EINVAL);
329 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
330 		return (0);
331 
332 	case SIOCGIFNETMASK:
333 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
334 		return (0);
335 
336 	case SIOCSIFDSTADDR:
337 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
338 			return (EINVAL);
339 		oldaddr = ia->ia_dstaddr;
340 		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
341 		if (ifp->if_ioctl && (error = (*ifp->if_ioctl)
342 					(ifp, SIOCSIFDSTADDR, (caddr_t)ia))) {
343 			ia->ia_dstaddr = oldaddr;
344 			return (error);
345 		}
346 		if (ia->ia_flags & IFA_ROUTE) {
347 			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
348 			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
349 			ia->ia_ifa.ifa_dstaddr =
350 					(struct sockaddr *)&ia->ia_dstaddr;
351 			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
352 		}
353 		return (0);
354 
355 	case SIOCSIFBRDADDR:
356 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
357 			return (EINVAL);
358 		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
359 		return (0);
360 
361 	case SIOCSIFADDR:
362 		error = in_ifinit(ifp, ia,
363 		    (struct sockaddr_in *) &ifr->ifr_addr, 1);
364 		if (error != 0 && iaIsNew)
365 			break;
366 		if (error == 0)
367 			EVENTHANDLER_INVOKE(ifaddr_event, ifp);
368 		return (0);
369 
370 	case SIOCSIFNETMASK:
371 		ia->ia_sockmask.sin_addr = ifra->ifra_addr.sin_addr;
372 		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr);
373 		return (0);
374 
375 	case SIOCAIFADDR:
376 		maskIsNew = 0;
377 		hostIsNew = 1;
378 		error = 0;
379 		if (ia->ia_addr.sin_family == AF_INET) {
380 			if (ifra->ifra_addr.sin_len == 0) {
381 				ifra->ifra_addr = ia->ia_addr;
382 				hostIsNew = 0;
383 			} else if (ifra->ifra_addr.sin_addr.s_addr ==
384 					       ia->ia_addr.sin_addr.s_addr)
385 				hostIsNew = 0;
386 		}
387 		if (ifra->ifra_mask.sin_len) {
388 			in_ifscrub(ifp, ia);
389 			ia->ia_sockmask = ifra->ifra_mask;
390 			ia->ia_sockmask.sin_family = AF_INET;
391 			ia->ia_subnetmask =
392 			     ntohl(ia->ia_sockmask.sin_addr.s_addr);
393 			maskIsNew = 1;
394 		}
395 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
396 		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
397 			in_ifscrub(ifp, ia);
398 			ia->ia_dstaddr = ifra->ifra_dstaddr;
399 			maskIsNew  = 1; /* We lie; but the effect's the same */
400 		}
401 		if (ifra->ifra_addr.sin_family == AF_INET &&
402 		    (hostIsNew || maskIsNew))
403 			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
404 		if (error != 0 && iaIsNew)
405 			break;
406 
407 		if ((ifp->if_flags & IFF_BROADCAST) &&
408 		    (ifra->ifra_broadaddr.sin_family == AF_INET))
409 			ia->ia_broadaddr = ifra->ifra_broadaddr;
410 		if (error == 0)
411 			EVENTHANDLER_INVOKE(ifaddr_event, ifp);
412 		return (error);
413 
414 	case SIOCDIFADDR:
415 		/*
416 		 * in_ifscrub kills the interface route.
417 		 */
418 		in_ifscrub(ifp, ia);
419 		/*
420 		 * in_ifadown gets rid of all the rest of
421 		 * the routes.  This is not quite the right
422 		 * thing to do, but at least if we are running
423 		 * a routing process they will come back.
424 		 */
425 		in_ifadown(&ia->ia_ifa, 1);
426 		/*
427 		 * XXX horrible hack to detect that we are being called
428 		 * from if_detach()
429 		 */
430 		if (ifaddr_byindex(ifp->if_index) == NULL) {
431 			in_pcbpurgeif0(&ripcbinfo, ifp);
432 			in_pcbpurgeif0(&udbinfo, ifp);
433 		}
434 		EVENTHANDLER_INVOKE(ifaddr_event, ifp);
435 		error = 0;
436 		break;
437 
438 	default:
439 		if (ifp == 0 || ifp->if_ioctl == 0)
440 			return (EOPNOTSUPP);
441 		return ((*ifp->if_ioctl)(ifp, cmd, data));
442 	}
443 
444 	/*
445 	 * Protect from ipintr() traversing address list while we're modifying
446 	 * it.
447 	 */
448 	s = splnet();
449 	TAILQ_REMOVE(&ifp->if_addrhead, &ia->ia_ifa, ifa_link);
450 	TAILQ_REMOVE(&in_ifaddrhead, ia, ia_link);
451 	LIST_REMOVE(ia, ia_hash);
452 	IFAFREE(&ia->ia_ifa);
453 	splx(s);
454 
455 	return (error);
456 }
457 
458 /*
459  * SIOC[GAD]LIFADDR.
460  *	SIOCGLIFADDR: get first address. (?!?)
461  *	SIOCGLIFADDR with IFLR_PREFIX:
462  *		get first address that matches the specified prefix.
463  *	SIOCALIFADDR: add the specified address.
464  *	SIOCALIFADDR with IFLR_PREFIX:
465  *		EINVAL since we can't deduce hostid part of the address.
466  *	SIOCDLIFADDR: delete the specified address.
467  *	SIOCDLIFADDR with IFLR_PREFIX:
468  *		delete the first address that matches the specified prefix.
469  * return values:
470  *	EINVAL on invalid parameters
471  *	EADDRNOTAVAIL on prefix match failed/specified address not found
472  *	other values may be returned from in_ioctl()
473  */
474 static int
475 in_lifaddr_ioctl(so, cmd, data, ifp, td)
476 	struct socket *so;
477 	u_long cmd;
478 	caddr_t	data;
479 	struct ifnet *ifp;
480 	struct thread *td;
481 {
482 	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
483 	struct ifaddr *ifa;
484 
485 	/* sanity checks */
486 	if (!data || !ifp) {
487 		panic("invalid argument to in_lifaddr_ioctl");
488 		/*NOTRECHED*/
489 	}
490 
491 	switch (cmd) {
492 	case SIOCGLIFADDR:
493 		/* address must be specified on GET with IFLR_PREFIX */
494 		if ((iflr->flags & IFLR_PREFIX) == 0)
495 			break;
496 		/*FALLTHROUGH*/
497 	case SIOCALIFADDR:
498 	case SIOCDLIFADDR:
499 		/* address must be specified on ADD and DELETE */
500 		if (iflr->addr.ss_family != AF_INET)
501 			return EINVAL;
502 		if (iflr->addr.ss_len != sizeof(struct sockaddr_in))
503 			return EINVAL;
504 		/* XXX need improvement */
505 		if (iflr->dstaddr.ss_family
506 		 && iflr->dstaddr.ss_family != AF_INET)
507 			return EINVAL;
508 		if (iflr->dstaddr.ss_family
509 		 && iflr->dstaddr.ss_len != sizeof(struct sockaddr_in))
510 			return EINVAL;
511 		break;
512 	default: /*shouldn't happen*/
513 		return EOPNOTSUPP;
514 	}
515 	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
516 		return EINVAL;
517 
518 	switch (cmd) {
519 	case SIOCALIFADDR:
520 	    {
521 		struct in_aliasreq ifra;
522 
523 		if (iflr->flags & IFLR_PREFIX)
524 			return EINVAL;
525 
526 		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
527 		bzero(&ifra, sizeof(ifra));
528 		bcopy(iflr->iflr_name, ifra.ifra_name,
529 			sizeof(ifra.ifra_name));
530 
531 		bcopy(&iflr->addr, &ifra.ifra_addr, iflr->addr.ss_len);
532 
533 		if (iflr->dstaddr.ss_family) {	/*XXX*/
534 			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
535 				iflr->dstaddr.ss_len);
536 		}
537 
538 		ifra.ifra_mask.sin_family = AF_INET;
539 		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
540 		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
541 
542 		return in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, td);
543 	    }
544 	case SIOCGLIFADDR:
545 	case SIOCDLIFADDR:
546 	    {
547 		struct in_ifaddr *ia;
548 		struct in_addr mask, candidate, match;
549 		struct sockaddr_in *sin;
550 		int cmp;
551 
552 		bzero(&mask, sizeof(mask));
553 		if (iflr->flags & IFLR_PREFIX) {
554 			/* lookup a prefix rather than address. */
555 			in_len2mask(&mask, iflr->prefixlen);
556 
557 			sin = (struct sockaddr_in *)&iflr->addr;
558 			match.s_addr = sin->sin_addr.s_addr;
559 			match.s_addr &= mask.s_addr;
560 
561 			/* if you set extra bits, that's wrong */
562 			if (match.s_addr != sin->sin_addr.s_addr)
563 				return EINVAL;
564 
565 			cmp = 1;
566 		} else {
567 			if (cmd == SIOCGLIFADDR) {
568 				/* on getting an address, take the 1st match */
569 				cmp = 0;	/*XXX*/
570 			} else {
571 				/* on deleting an address, do exact match */
572 				in_len2mask(&mask, 32);
573 				sin = (struct sockaddr_in *)&iflr->addr;
574 				match.s_addr = sin->sin_addr.s_addr;
575 
576 				cmp = 1;
577 			}
578 		}
579 
580 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)	{
581 			if (ifa->ifa_addr->sa_family != AF_INET6)
582 				continue;
583 			if (!cmp)
584 				break;
585 			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
586 			candidate.s_addr &= mask.s_addr;
587 			if (candidate.s_addr == match.s_addr)
588 				break;
589 		}
590 		if (!ifa)
591 			return EADDRNOTAVAIL;
592 		ia = (struct in_ifaddr *)ifa;
593 
594 		if (cmd == SIOCGLIFADDR) {
595 			/* fill in the if_laddrreq structure */
596 			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
597 
598 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
599 				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
600 					ia->ia_dstaddr.sin_len);
601 			} else
602 				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
603 
604 			iflr->prefixlen =
605 				in_mask2len(&ia->ia_sockmask.sin_addr);
606 
607 			iflr->flags = 0;	/*XXX*/
608 
609 			return 0;
610 		} else {
611 			struct in_aliasreq ifra;
612 
613 			/* fill in_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
614 			bzero(&ifra, sizeof(ifra));
615 			bcopy(iflr->iflr_name, ifra.ifra_name,
616 				sizeof(ifra.ifra_name));
617 
618 			bcopy(&ia->ia_addr, &ifra.ifra_addr,
619 				ia->ia_addr.sin_len);
620 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
621 				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
622 					ia->ia_dstaddr.sin_len);
623 			}
624 			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
625 				ia->ia_sockmask.sin_len);
626 
627 			return in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
628 					  ifp, td);
629 		}
630 	    }
631 	}
632 
633 	return EOPNOTSUPP;	/*just for safety*/
634 }
635 
636 /*
637  * Delete any existing route for an interface.
638  */
639 void
640 in_ifscrub(ifp, ia)
641 	register struct ifnet *ifp;
642 	register struct in_ifaddr *ia;
643 {
644 
645 	if ((ia->ia_flags & IFA_ROUTE) == 0)
646 		return;
647 	if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
648 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
649 	else
650 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
651 	ia->ia_flags &= ~IFA_ROUTE;
652 }
653 
654 /*
655  * Initialize an interface's internet address
656  * and routing table entry.
657  */
658 static int
659 in_ifinit(ifp, ia, sin, scrub)
660 	register struct ifnet *ifp;
661 	register struct in_ifaddr *ia;
662 	struct sockaddr_in *sin;
663 	int scrub;
664 {
665 	register u_long i = ntohl(sin->sin_addr.s_addr);
666 	struct sockaddr_in oldaddr;
667 	int s = splimp(), flags = RTF_UP, error = 0;
668 
669 	oldaddr = ia->ia_addr;
670 	if (oldaddr.sin_family == AF_INET)
671 		LIST_REMOVE(ia, ia_hash);
672 	ia->ia_addr = *sin;
673 	if (ia->ia_addr.sin_family == AF_INET)
674 		LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
675 		    ia, ia_hash);
676 	/*
677 	 * Give the interface a chance to initialize
678 	 * if this is its first address,
679 	 * and to validate the address if necessary.
680 	 */
681 	if (ifp->if_ioctl &&
682 	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
683 		splx(s);
684 		/* LIST_REMOVE(ia, ia_hash) is done in in_control */
685 		ia->ia_addr = oldaddr;
686 		if (ia->ia_addr.sin_family == AF_INET)
687 			LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
688 			    ia, ia_hash);
689 		return (error);
690 	}
691 	splx(s);
692 	if (scrub) {
693 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
694 		in_ifscrub(ifp, ia);
695 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
696 	}
697 	if (IN_CLASSA(i))
698 		ia->ia_netmask = IN_CLASSA_NET;
699 	else if (IN_CLASSB(i))
700 		ia->ia_netmask = IN_CLASSB_NET;
701 	else
702 		ia->ia_netmask = IN_CLASSC_NET;
703 	/*
704 	 * The subnet mask usually includes at least the standard network part,
705 	 * but may may be smaller in the case of supernetting.
706 	 * If it is set, we believe it.
707 	 */
708 	if (ia->ia_subnetmask == 0) {
709 		ia->ia_subnetmask = ia->ia_netmask;
710 		ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
711 	} else
712 		ia->ia_netmask &= ia->ia_subnetmask;
713 	ia->ia_net = i & ia->ia_netmask;
714 	ia->ia_subnet = i & ia->ia_subnetmask;
715 	in_socktrim(&ia->ia_sockmask);
716 	/*
717 	 * Add route for the network.
718 	 */
719 	ia->ia_ifa.ifa_metric = ifp->if_metric;
720 	if (ifp->if_flags & IFF_BROADCAST) {
721 		ia->ia_broadaddr.sin_addr.s_addr =
722 			htonl(ia->ia_subnet | ~ia->ia_subnetmask);
723 		ia->ia_netbroadcast.s_addr =
724 			htonl(ia->ia_net | ~ ia->ia_netmask);
725 	} else if (ifp->if_flags & IFF_LOOPBACK) {
726 		ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
727 		flags |= RTF_HOST;
728 	} else if (ifp->if_flags & IFF_POINTOPOINT) {
729 		if (ia->ia_dstaddr.sin_family != AF_INET)
730 			return (0);
731 		flags |= RTF_HOST;
732 	}
733 
734 	/*-
735 	 * Don't add host routes for interface addresses of
736 	 * 0.0.0.0 --> 0.255.255.255 netmask 255.0.0.0.  This makes it
737 	 * possible to assign several such address pairs with consistent
738 	 * results (no host route) and is required by BOOTP.
739 	 *
740 	 * XXX: This is ugly !  There should be a way for the caller to
741 	 *      say that they don't want a host route.
742 	 */
743 	if (ia->ia_addr.sin_addr.s_addr != INADDR_ANY ||
744 	    ia->ia_netmask != IN_CLASSA_NET ||
745 	    ia->ia_dstaddr.sin_addr.s_addr != htonl(IN_CLASSA_HOST)) {
746 		if ((error = rtinit(&ia->ia_ifa, (int)RTM_ADD, flags)) != 0) {
747 			ia->ia_addr = oldaddr;
748 			return (error);
749 		}
750 		ia->ia_flags |= IFA_ROUTE;
751 	}
752 
753 	/*
754 	 * If the interface supports multicast, join the "all hosts"
755 	 * multicast group on that interface.
756 	 */
757 	if (ifp->if_flags & IFF_MULTICAST) {
758 		struct in_addr addr;
759 
760 		addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
761 		in_addmulti(&addr, ifp);
762 	}
763 	return (error);
764 }
765 
766 
767 /*
768  * Return 1 if the address might be a local broadcast address.
769  */
770 int
771 in_broadcast(in, ifp)
772 	struct in_addr in;
773         struct ifnet *ifp;
774 {
775 	register struct ifaddr *ifa;
776 	u_long t;
777 
778 	if (in.s_addr == INADDR_BROADCAST ||
779 	    in.s_addr == INADDR_ANY)
780 		return 1;
781 	if ((ifp->if_flags & IFF_BROADCAST) == 0)
782 		return 0;
783 	t = ntohl(in.s_addr);
784 	/*
785 	 * Look through the list of addresses for a match
786 	 * with a broadcast address.
787 	 */
788 #define ia ((struct in_ifaddr *)ifa)
789 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
790 		if (ifa->ifa_addr->sa_family == AF_INET &&
791 		    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
792 		     in.s_addr == ia->ia_netbroadcast.s_addr ||
793 		     /*
794 		      * Check for old-style (host 0) broadcast.
795 		      */
796 		     t == ia->ia_subnet || t == ia->ia_net) &&
797 		     /*
798 		      * Check for an all one subnetmask. These
799 		      * only exist when an interface gets a secondary
800 		      * address.
801 		      */
802 		     ia->ia_subnetmask != (u_long)0xffffffff)
803 			    return 1;
804 	return (0);
805 #undef ia
806 }
807 /*
808  * Add an address to the list of IP multicast addresses for a given interface.
809  */
810 struct in_multi *
811 in_addmulti(ap, ifp)
812 	register struct in_addr *ap;
813 	register struct ifnet *ifp;
814 {
815 	register struct in_multi *inm;
816 	int error;
817 	struct sockaddr_in sin;
818 	struct ifmultiaddr *ifma;
819 	int s = splnet();
820 
821 	/*
822 	 * Call generic routine to add membership or increment
823 	 * refcount.  It wants addresses in the form of a sockaddr,
824 	 * so we build one here (being careful to zero the unused bytes).
825 	 */
826 	bzero(&sin, sizeof sin);
827 	sin.sin_family = AF_INET;
828 	sin.sin_len = sizeof sin;
829 	sin.sin_addr = *ap;
830 	error = if_addmulti(ifp, (struct sockaddr *)&sin, &ifma);
831 	if (error) {
832 		splx(s);
833 		return 0;
834 	}
835 
836 	/*
837 	 * If ifma->ifma_protospec is null, then if_addmulti() created
838 	 * a new record.  Otherwise, we are done.
839 	 */
840 	if (ifma->ifma_protospec != 0) {
841 		splx(s);
842 		return ifma->ifma_protospec;
843 	}
844 
845 	/* XXX - if_addmulti uses M_WAITOK.  Can this really be called
846 	   at interrupt time?  If so, need to fix if_addmulti. XXX */
847 	inm = (struct in_multi *)malloc(sizeof(*inm), M_IPMADDR,
848 	    M_NOWAIT | M_ZERO);
849 	if (inm == NULL) {
850 		splx(s);
851 		return (NULL);
852 	}
853 
854 	inm->inm_addr = *ap;
855 	inm->inm_ifp = ifp;
856 	inm->inm_ifma = ifma;
857 	ifma->ifma_protospec = inm;
858 	LIST_INSERT_HEAD(&in_multihead, inm, inm_link);
859 
860 	/*
861 	 * Let IGMP know that we have joined a new IP multicast group.
862 	 */
863 	igmp_joingroup(inm);
864 	splx(s);
865 	return (inm);
866 }
867 
868 /*
869  * Delete a multicast address record.
870  */
871 void
872 in_delmulti(inm)
873 	register struct in_multi *inm;
874 {
875 	struct ifmultiaddr *ifma = inm->inm_ifma;
876 	struct in_multi my_inm;
877 	int s = splnet();
878 
879 	my_inm.inm_ifp = NULL ; /* don't send the leave msg */
880 	if (ifma->ifma_refcount == 1) {
881 		/*
882 		 * No remaining claims to this record; let IGMP know that
883 		 * we are leaving the multicast group.
884 		 * But do it after the if_delmulti() which might reset
885 		 * the interface and nuke the packet.
886 		 */
887 		my_inm = *inm ;
888 		ifma->ifma_protospec = 0;
889 		LIST_REMOVE(inm, inm_link);
890 		free(inm, M_IPMADDR);
891 	}
892 	/* XXX - should be separate API for when we have an ifma? */
893 	if_delmulti(ifma->ifma_ifp, ifma->ifma_addr);
894 	if (my_inm.inm_ifp != NULL)
895 		igmp_leavegroup(&my_inm);
896 	splx(s);
897 }
898