xref: /freebsd/sys/netinet/in.c (revision 2546665afcaf0d53dc2c7058fee96354b3680f5a)
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  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	@(#)in.c	8.4 (Berkeley) 1/9/95
30  * $FreeBSD$
31  */
32 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/sockio.h>
36 #include <sys/malloc.h>
37 #include <sys/socket.h>
38 #include <sys/kernel.h>
39 #include <sys/sysctl.h>
40 
41 #include <net/if.h>
42 #include <net/if_types.h>
43 #include <net/route.h>
44 
45 #include <netinet/in.h>
46 #include <netinet/in_var.h>
47 #include <netinet/in_pcb.h>
48 
49 #include <netinet/igmp_var.h>
50 
51 static MALLOC_DEFINE(M_IPMADDR, "in_multi", "internet multicast address");
52 
53 static int in_mask2len(struct in_addr *);
54 static void in_len2mask(struct in_addr *, int);
55 static int in_lifaddr_ioctl(struct socket *, u_long, caddr_t,
56 	struct ifnet *, struct thread *);
57 
58 static void	in_socktrim(struct sockaddr_in *);
59 static int	in_ifinit(struct ifnet *,
60 	    struct in_ifaddr *, struct sockaddr_in *, int);
61 
62 static int subnetsarelocal = 0;
63 SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW,
64 	&subnetsarelocal, 0, "Treat all subnets as directly connected");
65 
66 struct in_multihead in_multihead; /* XXX BSS initialization */
67 
68 extern struct inpcbinfo ripcbinfo;
69 extern struct inpcbinfo udbinfo;
70 
71 /*
72  * Return 1 if an internet address is for a ``local'' host
73  * (one to which we have a connection).  If subnetsarelocal
74  * is true, this includes other subnets of the local net.
75  * Otherwise, it includes only the directly-connected (sub)nets.
76  */
77 int
78 in_localaddr(in)
79 	struct in_addr in;
80 {
81 	register u_long i = ntohl(in.s_addr);
82 	register struct in_ifaddr *ia;
83 
84 	if (subnetsarelocal) {
85 		TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link)
86 			if ((i & ia->ia_netmask) == ia->ia_net)
87 				return (1);
88 	} else {
89 		TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link)
90 			if ((i & ia->ia_subnetmask) == ia->ia_subnet)
91 				return (1);
92 	}
93 	return (0);
94 }
95 
96 /*
97  * Determine whether an IP address is in a reserved set of addresses
98  * that may not be forwarded, or whether datagrams to that destination
99  * may be forwarded.
100  */
101 int
102 in_canforward(in)
103 	struct in_addr in;
104 {
105 	register u_long i = ntohl(in.s_addr);
106 	register u_long net;
107 
108 	if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i))
109 		return (0);
110 	if (IN_CLASSA(i)) {
111 		net = i & IN_CLASSA_NET;
112 		if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
113 			return (0);
114 	}
115 	return (1);
116 }
117 
118 /*
119  * Trim a mask in a sockaddr
120  */
121 static void
122 in_socktrim(ap)
123 struct sockaddr_in *ap;
124 {
125     register char *cplim = (char *) &ap->sin_addr;
126     register char *cp = (char *) (&ap->sin_addr + 1);
127 
128     ap->sin_len = 0;
129     while (--cp >= cplim)
130         if (*cp) {
131 	    (ap)->sin_len = cp - (char *) (ap) + 1;
132 	    break;
133 	}
134 }
135 
136 static int
137 in_mask2len(mask)
138 	struct in_addr *mask;
139 {
140 	int x, y;
141 	u_char *p;
142 
143 	p = (u_char *)mask;
144 	for (x = 0; x < sizeof(*mask); x++) {
145 		if (p[x] != 0xff)
146 			break;
147 	}
148 	y = 0;
149 	if (x < sizeof(*mask)) {
150 		for (y = 0; y < 8; y++) {
151 			if ((p[x] & (0x80 >> y)) == 0)
152 				break;
153 		}
154 	}
155 	return x * 8 + y;
156 }
157 
158 static void
159 in_len2mask(mask, len)
160 	struct in_addr *mask;
161 	int len;
162 {
163 	int i;
164 	u_char *p;
165 
166 	p = (u_char *)mask;
167 	bzero(mask, sizeof(*mask));
168 	for (i = 0; i < len / 8; i++)
169 		p[i] = 0xff;
170 	if (len % 8)
171 		p[i] = (0xff00 >> (len % 8)) & 0xff;
172 }
173 
174 /*
175  * Generic internet control operations (ioctl's).
176  * Ifp is 0 if not an interface-specific ioctl.
177  */
178 /* ARGSUSED */
179 int
180 in_control(so, cmd, data, ifp, td)
181 	struct socket *so;
182 	u_long cmd;
183 	caddr_t data;
184 	register struct ifnet *ifp;
185 	struct thread *td;
186 {
187 	register struct ifreq *ifr = (struct ifreq *)data;
188 	register struct in_ifaddr *ia = 0, *iap;
189 	register struct ifaddr *ifa;
190 	struct in_addr dst;
191 	struct in_ifaddr *oia;
192 	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
193 	struct sockaddr_in oldaddr;
194 	int error, hostIsNew, iaIsNew, maskIsNew, s;
195 
196 	iaIsNew = 0;
197 
198 	switch (cmd) {
199 	case SIOCALIFADDR:
200 	case SIOCDLIFADDR:
201 		if (td && (error = suser(td)) != 0)
202 			return error;
203 		/*fall through*/
204 	case SIOCGLIFADDR:
205 		if (!ifp)
206 			return EINVAL;
207 		return in_lifaddr_ioctl(so, cmd, data, ifp, td);
208 	}
209 
210 	/*
211 	 * Find address for this interface, if it exists.
212 	 *
213 	 * If an alias address was specified, find that one instead of
214 	 * the first one on the interface, if possible.
215 	 */
216 	if (ifp) {
217 		dst = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
218 		LIST_FOREACH(iap, INADDR_HASH(dst.s_addr), ia_hash)
219 			if (iap->ia_ifp == ifp &&
220 			    iap->ia_addr.sin_addr.s_addr == dst.s_addr) {
221 				ia = iap;
222 				break;
223 			}
224 		if (ia == NULL)
225 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
226 				iap = ifatoia(ifa);
227 				if (iap->ia_addr.sin_family == AF_INET) {
228 					ia = iap;
229 					break;
230 				}
231 			}
232 	}
233 
234 	switch (cmd) {
235 
236 	case SIOCAIFADDR:
237 	case SIOCDIFADDR:
238 		if (ifp == 0)
239 			return (EADDRNOTAVAIL);
240 		if (ifra->ifra_addr.sin_family == AF_INET) {
241 			for (oia = ia; ia; ia = TAILQ_NEXT(ia, ia_link)) {
242 				if (ia->ia_ifp == ifp  &&
243 				    ia->ia_addr.sin_addr.s_addr ==
244 				    ifra->ifra_addr.sin_addr.s_addr)
245 					break;
246 			}
247 			if ((ifp->if_flags & IFF_POINTOPOINT)
248 			    && (cmd == SIOCAIFADDR)
249 			    && (ifra->ifra_dstaddr.sin_addr.s_addr
250 				== INADDR_ANY)) {
251 				return EDESTADDRREQ;
252 			}
253 		}
254 		if (cmd == SIOCDIFADDR && ia == 0)
255 			return (EADDRNOTAVAIL);
256 		/* FALLTHROUGH */
257 	case SIOCSIFADDR:
258 	case SIOCSIFNETMASK:
259 	case SIOCSIFDSTADDR:
260 		if (td && (error = suser(td)) != 0)
261 			return error;
262 
263 		if (ifp == 0)
264 			return (EADDRNOTAVAIL);
265 		if (ia == (struct in_ifaddr *)0) {
266 			ia = (struct in_ifaddr *)
267 				malloc(sizeof *ia, M_IFADDR, M_WAITOK | M_ZERO);
268 			if (ia == (struct in_ifaddr *)NULL)
269 				return (ENOBUFS);
270 			/*
271 			 * Protect from ipintr() traversing address list
272 			 * while we're modifying it.
273 			 */
274 			s = splnet();
275 			TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
276 
277 			ifa = &ia->ia_ifa;
278 			IFA_LOCK_INIT(ifa);
279 			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
280 			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
281 			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
282 			ifa->ifa_refcnt = 1;
283 			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
284 
285 			ia->ia_sockmask.sin_len = 8;
286 			ia->ia_sockmask.sin_family = AF_INET;
287 			if (ifp->if_flags & IFF_BROADCAST) {
288 				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
289 				ia->ia_broadaddr.sin_family = AF_INET;
290 			}
291 			ia->ia_ifp = ifp;
292 			splx(s);
293 			iaIsNew = 1;
294 		}
295 		break;
296 
297 	case SIOCSIFBRDADDR:
298 		if (td && (error = suser(td)) != 0)
299 			return error;
300 		/* FALLTHROUGH */
301 
302 	case SIOCGIFADDR:
303 	case SIOCGIFNETMASK:
304 	case SIOCGIFDSTADDR:
305 	case SIOCGIFBRDADDR:
306 		if (ia == (struct in_ifaddr *)0)
307 			return (EADDRNOTAVAIL);
308 		break;
309 	}
310 	switch (cmd) {
311 
312 	case SIOCGIFADDR:
313 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
314 		return (0);
315 
316 	case SIOCGIFBRDADDR:
317 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
318 			return (EINVAL);
319 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
320 		return (0);
321 
322 	case SIOCGIFDSTADDR:
323 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
324 			return (EINVAL);
325 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
326 		return (0);
327 
328 	case SIOCGIFNETMASK:
329 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
330 		return (0);
331 
332 	case SIOCSIFDSTADDR:
333 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
334 			return (EINVAL);
335 		oldaddr = ia->ia_dstaddr;
336 		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
337 		if (ifp->if_ioctl && (error = (*ifp->if_ioctl)
338 					(ifp, SIOCSIFDSTADDR, (caddr_t)ia))) {
339 			ia->ia_dstaddr = oldaddr;
340 			return (error);
341 		}
342 		if (ia->ia_flags & IFA_ROUTE) {
343 			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
344 			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
345 			ia->ia_ifa.ifa_dstaddr =
346 					(struct sockaddr *)&ia->ia_dstaddr;
347 			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
348 		}
349 		return (0);
350 
351 	case SIOCSIFBRDADDR:
352 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
353 			return (EINVAL);
354 		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
355 		return (0);
356 
357 	case SIOCSIFADDR:
358 		error = in_ifinit(ifp, ia,
359 		    (struct sockaddr_in *) &ifr->ifr_addr, 1);
360 		if (error != 0 && iaIsNew)
361 			break;
362 		if (error == 0)
363 			EVENTHANDLER_INVOKE(ifaddr_event, ifp);
364 		return (0);
365 
366 	case SIOCSIFNETMASK:
367 		ia->ia_sockmask.sin_addr = ifra->ifra_addr.sin_addr;
368 		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr);
369 		return (0);
370 
371 	case SIOCAIFADDR:
372 		maskIsNew = 0;
373 		hostIsNew = 1;
374 		error = 0;
375 		if (ia->ia_addr.sin_family == AF_INET) {
376 			if (ifra->ifra_addr.sin_len == 0) {
377 				ifra->ifra_addr = ia->ia_addr;
378 				hostIsNew = 0;
379 			} else if (ifra->ifra_addr.sin_addr.s_addr ==
380 					       ia->ia_addr.sin_addr.s_addr)
381 				hostIsNew = 0;
382 		}
383 		if (ifra->ifra_mask.sin_len) {
384 			in_ifscrub(ifp, ia);
385 			ia->ia_sockmask = ifra->ifra_mask;
386 			ia->ia_sockmask.sin_family = AF_INET;
387 			ia->ia_subnetmask =
388 			     ntohl(ia->ia_sockmask.sin_addr.s_addr);
389 			maskIsNew = 1;
390 		}
391 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
392 		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
393 			in_ifscrub(ifp, ia);
394 			ia->ia_dstaddr = ifra->ifra_dstaddr;
395 			maskIsNew  = 1; /* We lie; but the effect's the same */
396 		}
397 		if (ifra->ifra_addr.sin_family == AF_INET &&
398 		    (hostIsNew || maskIsNew))
399 			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
400 		if (error != 0 && iaIsNew)
401 			break;
402 
403 		if ((ifp->if_flags & IFF_BROADCAST) &&
404 		    (ifra->ifra_broadaddr.sin_family == AF_INET))
405 			ia->ia_broadaddr = ifra->ifra_broadaddr;
406 		if (error == 0)
407 			EVENTHANDLER_INVOKE(ifaddr_event, ifp);
408 		return (error);
409 
410 	case SIOCDIFADDR:
411 		/*
412 		 * in_ifscrub kills the interface route.
413 		 */
414 		in_ifscrub(ifp, ia);
415 		/*
416 		 * in_ifadown gets rid of all the rest of
417 		 * the routes.  This is not quite the right
418 		 * thing to do, but at least if we are running
419 		 * a routing process they will come back.
420 		 */
421 		in_ifadown(&ia->ia_ifa, 1);
422 		/*
423 		 * XXX horrible hack to detect that we are being called
424 		 * from if_detach()
425 		 */
426 		if (ifaddr_byindex(ifp->if_index) == NULL) {
427 			in_pcbpurgeif0(&ripcbinfo, ifp);
428 			in_pcbpurgeif0(&udbinfo, ifp);
429 		}
430 		EVENTHANDLER_INVOKE(ifaddr_event, ifp);
431 		error = 0;
432 		break;
433 
434 	default:
435 		if (ifp == 0 || ifp->if_ioctl == 0)
436 			return (EOPNOTSUPP);
437 		return ((*ifp->if_ioctl)(ifp, cmd, data));
438 	}
439 
440 	/*
441 	 * Protect from ipintr() traversing address list while we're modifying
442 	 * it.
443 	 */
444 	s = splnet();
445 	TAILQ_REMOVE(&ifp->if_addrhead, &ia->ia_ifa, ifa_link);
446 	TAILQ_REMOVE(&in_ifaddrhead, ia, ia_link);
447 	LIST_REMOVE(ia, ia_hash);
448 	IFAFREE(&ia->ia_ifa);
449 	splx(s);
450 
451 	return (error);
452 }
453 
454 /*
455  * SIOC[GAD]LIFADDR.
456  *	SIOCGLIFADDR: get first address. (?!?)
457  *	SIOCGLIFADDR with IFLR_PREFIX:
458  *		get first address that matches the specified prefix.
459  *	SIOCALIFADDR: add the specified address.
460  *	SIOCALIFADDR with IFLR_PREFIX:
461  *		EINVAL since we can't deduce hostid part of the address.
462  *	SIOCDLIFADDR: delete the specified address.
463  *	SIOCDLIFADDR with IFLR_PREFIX:
464  *		delete the first address that matches the specified prefix.
465  * return values:
466  *	EINVAL on invalid parameters
467  *	EADDRNOTAVAIL on prefix match failed/specified address not found
468  *	other values may be returned from in_ioctl()
469  */
470 static int
471 in_lifaddr_ioctl(so, cmd, data, ifp, td)
472 	struct socket *so;
473 	u_long cmd;
474 	caddr_t	data;
475 	struct ifnet *ifp;
476 	struct thread *td;
477 {
478 	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
479 	struct ifaddr *ifa;
480 
481 	/* sanity checks */
482 	if (!data || !ifp) {
483 		panic("invalid argument to in_lifaddr_ioctl");
484 		/*NOTRECHED*/
485 	}
486 
487 	switch (cmd) {
488 	case SIOCGLIFADDR:
489 		/* address must be specified on GET with IFLR_PREFIX */
490 		if ((iflr->flags & IFLR_PREFIX) == 0)
491 			break;
492 		/*FALLTHROUGH*/
493 	case SIOCALIFADDR:
494 	case SIOCDLIFADDR:
495 		/* address must be specified on ADD and DELETE */
496 		if (iflr->addr.ss_family != AF_INET)
497 			return EINVAL;
498 		if (iflr->addr.ss_len != sizeof(struct sockaddr_in))
499 			return EINVAL;
500 		/* XXX need improvement */
501 		if (iflr->dstaddr.ss_family
502 		 && iflr->dstaddr.ss_family != AF_INET)
503 			return EINVAL;
504 		if (iflr->dstaddr.ss_family
505 		 && iflr->dstaddr.ss_len != sizeof(struct sockaddr_in))
506 			return EINVAL;
507 		break;
508 	default: /*shouldn't happen*/
509 		return EOPNOTSUPP;
510 	}
511 	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
512 		return EINVAL;
513 
514 	switch (cmd) {
515 	case SIOCALIFADDR:
516 	    {
517 		struct in_aliasreq ifra;
518 
519 		if (iflr->flags & IFLR_PREFIX)
520 			return EINVAL;
521 
522 		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
523 		bzero(&ifra, sizeof(ifra));
524 		bcopy(iflr->iflr_name, ifra.ifra_name,
525 			sizeof(ifra.ifra_name));
526 
527 		bcopy(&iflr->addr, &ifra.ifra_addr, iflr->addr.ss_len);
528 
529 		if (iflr->dstaddr.ss_family) {	/*XXX*/
530 			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
531 				iflr->dstaddr.ss_len);
532 		}
533 
534 		ifra.ifra_mask.sin_family = AF_INET;
535 		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
536 		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
537 
538 		return in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, td);
539 	    }
540 	case SIOCGLIFADDR:
541 	case SIOCDLIFADDR:
542 	    {
543 		struct in_ifaddr *ia;
544 		struct in_addr mask, candidate, match;
545 		struct sockaddr_in *sin;
546 		int cmp;
547 
548 		bzero(&mask, sizeof(mask));
549 		if (iflr->flags & IFLR_PREFIX) {
550 			/* lookup a prefix rather than address. */
551 			in_len2mask(&mask, iflr->prefixlen);
552 
553 			sin = (struct sockaddr_in *)&iflr->addr;
554 			match.s_addr = sin->sin_addr.s_addr;
555 			match.s_addr &= mask.s_addr;
556 
557 			/* if you set extra bits, that's wrong */
558 			if (match.s_addr != sin->sin_addr.s_addr)
559 				return EINVAL;
560 
561 			cmp = 1;
562 		} else {
563 			if (cmd == SIOCGLIFADDR) {
564 				/* on getting an address, take the 1st match */
565 				cmp = 0;	/*XXX*/
566 			} else {
567 				/* on deleting an address, do exact match */
568 				in_len2mask(&mask, 32);
569 				sin = (struct sockaddr_in *)&iflr->addr;
570 				match.s_addr = sin->sin_addr.s_addr;
571 
572 				cmp = 1;
573 			}
574 		}
575 
576 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)	{
577 			if (ifa->ifa_addr->sa_family != AF_INET6)
578 				continue;
579 			if (!cmp)
580 				break;
581 			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
582 			candidate.s_addr &= mask.s_addr;
583 			if (candidate.s_addr == match.s_addr)
584 				break;
585 		}
586 		if (!ifa)
587 			return EADDRNOTAVAIL;
588 		ia = (struct in_ifaddr *)ifa;
589 
590 		if (cmd == SIOCGLIFADDR) {
591 			/* fill in the if_laddrreq structure */
592 			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
593 
594 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
595 				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
596 					ia->ia_dstaddr.sin_len);
597 			} else
598 				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
599 
600 			iflr->prefixlen =
601 				in_mask2len(&ia->ia_sockmask.sin_addr);
602 
603 			iflr->flags = 0;	/*XXX*/
604 
605 			return 0;
606 		} else {
607 			struct in_aliasreq ifra;
608 
609 			/* fill in_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
610 			bzero(&ifra, sizeof(ifra));
611 			bcopy(iflr->iflr_name, ifra.ifra_name,
612 				sizeof(ifra.ifra_name));
613 
614 			bcopy(&ia->ia_addr, &ifra.ifra_addr,
615 				ia->ia_addr.sin_len);
616 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
617 				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
618 					ia->ia_dstaddr.sin_len);
619 			}
620 			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
621 				ia->ia_sockmask.sin_len);
622 
623 			return in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
624 					  ifp, td);
625 		}
626 	    }
627 	}
628 
629 	return EOPNOTSUPP;	/*just for safety*/
630 }
631 
632 /*
633  * Delete any existing route for an interface.
634  */
635 void
636 in_ifscrub(ifp, ia)
637 	register struct ifnet *ifp;
638 	register struct in_ifaddr *ia;
639 {
640 
641 	if ((ia->ia_flags & IFA_ROUTE) == 0)
642 		return;
643 	if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
644 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
645 	else
646 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
647 	ia->ia_flags &= ~IFA_ROUTE;
648 }
649 
650 /*
651  * Initialize an interface's internet address
652  * and routing table entry.
653  */
654 static int
655 in_ifinit(ifp, ia, sin, scrub)
656 	register struct ifnet *ifp;
657 	register struct in_ifaddr *ia;
658 	struct sockaddr_in *sin;
659 	int scrub;
660 {
661 	register u_long i = ntohl(sin->sin_addr.s_addr);
662 	struct sockaddr_in oldaddr;
663 	int s = splimp(), flags = RTF_UP, error = 0;
664 
665 	oldaddr = ia->ia_addr;
666 	if (oldaddr.sin_family == AF_INET)
667 		LIST_REMOVE(ia, ia_hash);
668 	ia->ia_addr = *sin;
669 	if (ia->ia_addr.sin_family == AF_INET)
670 		LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
671 		    ia, ia_hash);
672 	/*
673 	 * Give the interface a chance to initialize
674 	 * if this is its first address,
675 	 * and to validate the address if necessary.
676 	 */
677 	if (ifp->if_ioctl &&
678 	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
679 		splx(s);
680 		/* LIST_REMOVE(ia, ia_hash) is done in in_control */
681 		ia->ia_addr = oldaddr;
682 		if (ia->ia_addr.sin_family == AF_INET)
683 			LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
684 			    ia, ia_hash);
685 		return (error);
686 	}
687 	splx(s);
688 	if (scrub) {
689 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
690 		in_ifscrub(ifp, ia);
691 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
692 	}
693 	if (IN_CLASSA(i))
694 		ia->ia_netmask = IN_CLASSA_NET;
695 	else if (IN_CLASSB(i))
696 		ia->ia_netmask = IN_CLASSB_NET;
697 	else
698 		ia->ia_netmask = IN_CLASSC_NET;
699 	/*
700 	 * The subnet mask usually includes at least the standard network part,
701 	 * but may may be smaller in the case of supernetting.
702 	 * If it is set, we believe it.
703 	 */
704 	if (ia->ia_subnetmask == 0) {
705 		ia->ia_subnetmask = ia->ia_netmask;
706 		ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
707 	} else
708 		ia->ia_netmask &= ia->ia_subnetmask;
709 	ia->ia_net = i & ia->ia_netmask;
710 	ia->ia_subnet = i & ia->ia_subnetmask;
711 	in_socktrim(&ia->ia_sockmask);
712 	/*
713 	 * Add route for the network.
714 	 */
715 	ia->ia_ifa.ifa_metric = ifp->if_metric;
716 	if (ifp->if_flags & IFF_BROADCAST) {
717 		ia->ia_broadaddr.sin_addr.s_addr =
718 			htonl(ia->ia_subnet | ~ia->ia_subnetmask);
719 		ia->ia_netbroadcast.s_addr =
720 			htonl(ia->ia_net | ~ ia->ia_netmask);
721 	} else if (ifp->if_flags & IFF_LOOPBACK) {
722 		ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
723 		flags |= RTF_HOST;
724 	} else if (ifp->if_flags & IFF_POINTOPOINT) {
725 		if (ia->ia_dstaddr.sin_family != AF_INET)
726 			return (0);
727 		flags |= RTF_HOST;
728 	}
729 
730 	/*-
731 	 * Don't add host routes for interface addresses of
732 	 * 0.0.0.0 --> 0.255.255.255 netmask 255.0.0.0.  This makes it
733 	 * possible to assign several such address pairs with consistent
734 	 * results (no host route) and is required by BOOTP.
735 	 *
736 	 * XXX: This is ugly !  There should be a way for the caller to
737 	 *      say that they don't want a host route.
738 	 */
739 	if (ia->ia_addr.sin_addr.s_addr != INADDR_ANY ||
740 	    ia->ia_netmask != IN_CLASSA_NET ||
741 	    ia->ia_dstaddr.sin_addr.s_addr != htonl(IN_CLASSA_HOST)) {
742 		if ((error = rtinit(&ia->ia_ifa, (int)RTM_ADD, flags)) != 0) {
743 			ia->ia_addr = oldaddr;
744 			return (error);
745 		}
746 		ia->ia_flags |= IFA_ROUTE;
747 	}
748 
749 	/*
750 	 * If the interface supports multicast, join the "all hosts"
751 	 * multicast group on that interface.
752 	 */
753 	if (ifp->if_flags & IFF_MULTICAST) {
754 		struct in_addr addr;
755 
756 		addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
757 		in_addmulti(&addr, ifp);
758 	}
759 	return (error);
760 }
761 
762 
763 /*
764  * Return 1 if the address might be a local broadcast address.
765  */
766 int
767 in_broadcast(in, ifp)
768 	struct in_addr in;
769         struct ifnet *ifp;
770 {
771 	register struct ifaddr *ifa;
772 	u_long t;
773 
774 	if (in.s_addr == INADDR_BROADCAST ||
775 	    in.s_addr == INADDR_ANY)
776 		return 1;
777 	if ((ifp->if_flags & IFF_BROADCAST) == 0)
778 		return 0;
779 	t = ntohl(in.s_addr);
780 	/*
781 	 * Look through the list of addresses for a match
782 	 * with a broadcast address.
783 	 */
784 #define ia ((struct in_ifaddr *)ifa)
785 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
786 		if (ifa->ifa_addr->sa_family == AF_INET &&
787 		    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
788 		     in.s_addr == ia->ia_netbroadcast.s_addr ||
789 		     /*
790 		      * Check for old-style (host 0) broadcast.
791 		      */
792 		     t == ia->ia_subnet || t == ia->ia_net) &&
793 		     /*
794 		      * Check for an all one subnetmask. These
795 		      * only exist when an interface gets a secondary
796 		      * address.
797 		      */
798 		     ia->ia_subnetmask != (u_long)0xffffffff)
799 			    return 1;
800 	return (0);
801 #undef ia
802 }
803 /*
804  * Add an address to the list of IP multicast addresses for a given interface.
805  */
806 struct in_multi *
807 in_addmulti(ap, ifp)
808 	register struct in_addr *ap;
809 	register struct ifnet *ifp;
810 {
811 	register struct in_multi *inm;
812 	int error;
813 	struct sockaddr_in sin;
814 	struct ifmultiaddr *ifma;
815 	int s = splnet();
816 
817 	/*
818 	 * Call generic routine to add membership or increment
819 	 * refcount.  It wants addresses in the form of a sockaddr,
820 	 * so we build one here (being careful to zero the unused bytes).
821 	 */
822 	bzero(&sin, sizeof sin);
823 	sin.sin_family = AF_INET;
824 	sin.sin_len = sizeof sin;
825 	sin.sin_addr = *ap;
826 	error = if_addmulti(ifp, (struct sockaddr *)&sin, &ifma);
827 	if (error) {
828 		splx(s);
829 		return 0;
830 	}
831 
832 	/*
833 	 * If ifma->ifma_protospec is null, then if_addmulti() created
834 	 * a new record.  Otherwise, we are done.
835 	 */
836 	if (ifma->ifma_protospec != 0) {
837 		splx(s);
838 		return ifma->ifma_protospec;
839 	}
840 
841 	/* XXX - if_addmulti uses M_WAITOK.  Can this really be called
842 	   at interrupt time?  If so, need to fix if_addmulti. XXX */
843 	inm = (struct in_multi *)malloc(sizeof(*inm), M_IPMADDR,
844 	    M_NOWAIT | M_ZERO);
845 	if (inm == NULL) {
846 		splx(s);
847 		return (NULL);
848 	}
849 
850 	inm->inm_addr = *ap;
851 	inm->inm_ifp = ifp;
852 	inm->inm_ifma = ifma;
853 	ifma->ifma_protospec = inm;
854 	LIST_INSERT_HEAD(&in_multihead, inm, inm_link);
855 
856 	/*
857 	 * Let IGMP know that we have joined a new IP multicast group.
858 	 */
859 	igmp_joingroup(inm);
860 	splx(s);
861 	return (inm);
862 }
863 
864 /*
865  * Delete a multicast address record.
866  */
867 void
868 in_delmulti(inm)
869 	register struct in_multi *inm;
870 {
871 	struct ifmultiaddr *ifma = inm->inm_ifma;
872 	struct in_multi my_inm;
873 	int s = splnet();
874 
875 	my_inm.inm_ifp = NULL ; /* don't send the leave msg */
876 	if (ifma->ifma_refcount == 1) {
877 		/*
878 		 * No remaining claims to this record; let IGMP know that
879 		 * we are leaving the multicast group.
880 		 * But do it after the if_delmulti() which might reset
881 		 * the interface and nuke the packet.
882 		 */
883 		my_inm = *inm ;
884 		ifma->ifma_protospec = 0;
885 		LIST_REMOVE(inm, inm_link);
886 		free(inm, M_IPMADDR);
887 	}
888 	/* XXX - should be separate API for when we have an ifma? */
889 	if_delmulti(ifma->ifma_ifp, ifma->ifma_addr);
890 	if (my_inm.inm_ifp != NULL)
891 		igmp_leavegroup(&my_inm);
892 	splx(s);
893 }
894