xref: /freebsd/sys/netinet/in.c (revision c37420b0d5b3b6ef875fbf0b84a13f6f09be56d6)
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  * Return 1 if an internet address is for the local host and configured
98  * on one of its interfaces.
99  */
100 int
101 in_localip(in)
102 	struct in_addr in;
103 {
104 	struct in_ifaddr *ia;
105 
106 	LIST_FOREACH(ia, INADDR_HASH(in.s_addr), ia_hash) {
107 		if (IA_SIN(ia)->sin_addr.s_addr == in.s_addr)
108 			return 1;
109 	}
110 	return 0;
111 }
112 
113 /*
114  * Determine whether an IP address is in a reserved set of addresses
115  * that may not be forwarded, or whether datagrams to that destination
116  * may be forwarded.
117  */
118 int
119 in_canforward(in)
120 	struct in_addr in;
121 {
122 	register u_long i = ntohl(in.s_addr);
123 	register u_long net;
124 
125 	if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i))
126 		return (0);
127 	if (IN_CLASSA(i)) {
128 		net = i & IN_CLASSA_NET;
129 		if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
130 			return (0);
131 	}
132 	return (1);
133 }
134 
135 /*
136  * Trim a mask in a sockaddr
137  */
138 static void
139 in_socktrim(ap)
140 struct sockaddr_in *ap;
141 {
142     register char *cplim = (char *) &ap->sin_addr;
143     register char *cp = (char *) (&ap->sin_addr + 1);
144 
145     ap->sin_len = 0;
146     while (--cp >= cplim)
147         if (*cp) {
148 	    (ap)->sin_len = cp - (char *) (ap) + 1;
149 	    break;
150 	}
151 }
152 
153 static int
154 in_mask2len(mask)
155 	struct in_addr *mask;
156 {
157 	int x, y;
158 	u_char *p;
159 
160 	p = (u_char *)mask;
161 	for (x = 0; x < sizeof(*mask); x++) {
162 		if (p[x] != 0xff)
163 			break;
164 	}
165 	y = 0;
166 	if (x < sizeof(*mask)) {
167 		for (y = 0; y < 8; y++) {
168 			if ((p[x] & (0x80 >> y)) == 0)
169 				break;
170 		}
171 	}
172 	return x * 8 + y;
173 }
174 
175 static void
176 in_len2mask(mask, len)
177 	struct in_addr *mask;
178 	int len;
179 {
180 	int i;
181 	u_char *p;
182 
183 	p = (u_char *)mask;
184 	bzero(mask, sizeof(*mask));
185 	for (i = 0; i < len / 8; i++)
186 		p[i] = 0xff;
187 	if (len % 8)
188 		p[i] = (0xff00 >> (len % 8)) & 0xff;
189 }
190 
191 /*
192  * Generic internet control operations (ioctl's).
193  * Ifp is 0 if not an interface-specific ioctl.
194  */
195 /* ARGSUSED */
196 int
197 in_control(so, cmd, data, ifp, td)
198 	struct socket *so;
199 	u_long cmd;
200 	caddr_t data;
201 	register struct ifnet *ifp;
202 	struct thread *td;
203 {
204 	register struct ifreq *ifr = (struct ifreq *)data;
205 	register struct in_ifaddr *ia = 0, *iap;
206 	register struct ifaddr *ifa;
207 	struct in_addr dst;
208 	struct in_ifaddr *oia;
209 	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
210 	struct sockaddr_in oldaddr;
211 	int error, hostIsNew, iaIsNew, maskIsNew, s;
212 
213 	iaIsNew = 0;
214 
215 	switch (cmd) {
216 	case SIOCALIFADDR:
217 	case SIOCDLIFADDR:
218 		if (td && (error = suser(td)) != 0)
219 			return error;
220 		/*fall through*/
221 	case SIOCGLIFADDR:
222 		if (!ifp)
223 			return EINVAL;
224 		return in_lifaddr_ioctl(so, cmd, data, ifp, td);
225 	}
226 
227 	/*
228 	 * Find address for this interface, if it exists.
229 	 *
230 	 * If an alias address was specified, find that one instead of
231 	 * the first one on the interface, if possible.
232 	 */
233 	if (ifp) {
234 		dst = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
235 		LIST_FOREACH(iap, INADDR_HASH(dst.s_addr), ia_hash)
236 			if (iap->ia_ifp == ifp &&
237 			    iap->ia_addr.sin_addr.s_addr == dst.s_addr) {
238 				ia = iap;
239 				break;
240 			}
241 		if (ia == NULL)
242 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
243 				iap = ifatoia(ifa);
244 				if (iap->ia_addr.sin_family == AF_INET) {
245 					ia = iap;
246 					break;
247 				}
248 			}
249 	}
250 
251 	switch (cmd) {
252 
253 	case SIOCAIFADDR:
254 	case SIOCDIFADDR:
255 		if (ifp == 0)
256 			return (EADDRNOTAVAIL);
257 		if (ifra->ifra_addr.sin_family == AF_INET) {
258 			for (oia = ia; ia; ia = TAILQ_NEXT(ia, ia_link)) {
259 				if (ia->ia_ifp == ifp  &&
260 				    ia->ia_addr.sin_addr.s_addr ==
261 				    ifra->ifra_addr.sin_addr.s_addr)
262 					break;
263 			}
264 			if ((ifp->if_flags & IFF_POINTOPOINT)
265 			    && (cmd == SIOCAIFADDR)
266 			    && (ifra->ifra_dstaddr.sin_addr.s_addr
267 				== INADDR_ANY)) {
268 				return EDESTADDRREQ;
269 			}
270 		}
271 		if (cmd == SIOCDIFADDR && ia == 0)
272 			return (EADDRNOTAVAIL);
273 		/* FALLTHROUGH */
274 	case SIOCSIFADDR:
275 	case SIOCSIFNETMASK:
276 	case SIOCSIFDSTADDR:
277 		if (td && (error = suser(td)) != 0)
278 			return error;
279 
280 		if (ifp == 0)
281 			return (EADDRNOTAVAIL);
282 		if (ia == (struct in_ifaddr *)0) {
283 			ia = (struct in_ifaddr *)
284 				malloc(sizeof *ia, M_IFADDR, M_WAITOK | M_ZERO);
285 			if (ia == (struct in_ifaddr *)NULL)
286 				return (ENOBUFS);
287 			/*
288 			 * Protect from ipintr() traversing address list
289 			 * while we're modifying it.
290 			 */
291 			s = splnet();
292 			TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
293 
294 			ifa = &ia->ia_ifa;
295 			IFA_LOCK_INIT(ifa);
296 			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
297 			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
298 			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
299 			ifa->ifa_refcnt = 1;
300 			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
301 
302 			ia->ia_sockmask.sin_len = 8;
303 			ia->ia_sockmask.sin_family = AF_INET;
304 			if (ifp->if_flags & IFF_BROADCAST) {
305 				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
306 				ia->ia_broadaddr.sin_family = AF_INET;
307 			}
308 			ia->ia_ifp = ifp;
309 			splx(s);
310 			iaIsNew = 1;
311 		}
312 		break;
313 
314 	case SIOCSIFBRDADDR:
315 		if (td && (error = suser(td)) != 0)
316 			return error;
317 		/* FALLTHROUGH */
318 
319 	case SIOCGIFADDR:
320 	case SIOCGIFNETMASK:
321 	case SIOCGIFDSTADDR:
322 	case SIOCGIFBRDADDR:
323 		if (ia == (struct in_ifaddr *)0)
324 			return (EADDRNOTAVAIL);
325 		break;
326 	}
327 	switch (cmd) {
328 
329 	case SIOCGIFADDR:
330 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
331 		return (0);
332 
333 	case SIOCGIFBRDADDR:
334 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
335 			return (EINVAL);
336 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
337 		return (0);
338 
339 	case SIOCGIFDSTADDR:
340 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
341 			return (EINVAL);
342 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
343 		return (0);
344 
345 	case SIOCGIFNETMASK:
346 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
347 		return (0);
348 
349 	case SIOCSIFDSTADDR:
350 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
351 			return (EINVAL);
352 		oldaddr = ia->ia_dstaddr;
353 		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
354 		if (ifp->if_ioctl && (error = (*ifp->if_ioctl)
355 					(ifp, SIOCSIFDSTADDR, (caddr_t)ia))) {
356 			ia->ia_dstaddr = oldaddr;
357 			return (error);
358 		}
359 		if (ia->ia_flags & IFA_ROUTE) {
360 			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
361 			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
362 			ia->ia_ifa.ifa_dstaddr =
363 					(struct sockaddr *)&ia->ia_dstaddr;
364 			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
365 		}
366 		return (0);
367 
368 	case SIOCSIFBRDADDR:
369 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
370 			return (EINVAL);
371 		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
372 		return (0);
373 
374 	case SIOCSIFADDR:
375 		error = in_ifinit(ifp, ia,
376 		    (struct sockaddr_in *) &ifr->ifr_addr, 1);
377 		if (error != 0 && iaIsNew)
378 			break;
379 		if (error == 0)
380 			EVENTHANDLER_INVOKE(ifaddr_event, ifp);
381 		return (0);
382 
383 	case SIOCSIFNETMASK:
384 		ia->ia_sockmask.sin_addr = ifra->ifra_addr.sin_addr;
385 		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr);
386 		return (0);
387 
388 	case SIOCAIFADDR:
389 		maskIsNew = 0;
390 		hostIsNew = 1;
391 		error = 0;
392 		if (ia->ia_addr.sin_family == AF_INET) {
393 			if (ifra->ifra_addr.sin_len == 0) {
394 				ifra->ifra_addr = ia->ia_addr;
395 				hostIsNew = 0;
396 			} else if (ifra->ifra_addr.sin_addr.s_addr ==
397 					       ia->ia_addr.sin_addr.s_addr)
398 				hostIsNew = 0;
399 		}
400 		if (ifra->ifra_mask.sin_len) {
401 			in_ifscrub(ifp, ia);
402 			ia->ia_sockmask = ifra->ifra_mask;
403 			ia->ia_sockmask.sin_family = AF_INET;
404 			ia->ia_subnetmask =
405 			     ntohl(ia->ia_sockmask.sin_addr.s_addr);
406 			maskIsNew = 1;
407 		}
408 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
409 		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
410 			in_ifscrub(ifp, ia);
411 			ia->ia_dstaddr = ifra->ifra_dstaddr;
412 			maskIsNew  = 1; /* We lie; but the effect's the same */
413 		}
414 		if (ifra->ifra_addr.sin_family == AF_INET &&
415 		    (hostIsNew || maskIsNew))
416 			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
417 		if (error != 0 && iaIsNew)
418 			break;
419 
420 		if ((ifp->if_flags & IFF_BROADCAST) &&
421 		    (ifra->ifra_broadaddr.sin_family == AF_INET))
422 			ia->ia_broadaddr = ifra->ifra_broadaddr;
423 		if (error == 0)
424 			EVENTHANDLER_INVOKE(ifaddr_event, ifp);
425 		return (error);
426 
427 	case SIOCDIFADDR:
428 		/*
429 		 * in_ifscrub kills the interface route.
430 		 */
431 		in_ifscrub(ifp, ia);
432 		/*
433 		 * in_ifadown gets rid of all the rest of
434 		 * the routes.  This is not quite the right
435 		 * thing to do, but at least if we are running
436 		 * a routing process they will come back.
437 		 */
438 		in_ifadown(&ia->ia_ifa, 1);
439 		/*
440 		 * XXX horrible hack to detect that we are being called
441 		 * from if_detach()
442 		 */
443 		if (ifaddr_byindex(ifp->if_index) == NULL) {
444 			in_pcbpurgeif0(&ripcbinfo, ifp);
445 			in_pcbpurgeif0(&udbinfo, ifp);
446 		}
447 		EVENTHANDLER_INVOKE(ifaddr_event, ifp);
448 		error = 0;
449 		break;
450 
451 	default:
452 		if (ifp == 0 || ifp->if_ioctl == 0)
453 			return (EOPNOTSUPP);
454 		return ((*ifp->if_ioctl)(ifp, cmd, data));
455 	}
456 
457 	/*
458 	 * Protect from ipintr() traversing address list while we're modifying
459 	 * it.
460 	 */
461 	s = splnet();
462 	TAILQ_REMOVE(&ifp->if_addrhead, &ia->ia_ifa, ifa_link);
463 	TAILQ_REMOVE(&in_ifaddrhead, ia, ia_link);
464 	LIST_REMOVE(ia, ia_hash);
465 	IFAFREE(&ia->ia_ifa);
466 	splx(s);
467 
468 	return (error);
469 }
470 
471 /*
472  * SIOC[GAD]LIFADDR.
473  *	SIOCGLIFADDR: get first address. (?!?)
474  *	SIOCGLIFADDR with IFLR_PREFIX:
475  *		get first address that matches the specified prefix.
476  *	SIOCALIFADDR: add the specified address.
477  *	SIOCALIFADDR with IFLR_PREFIX:
478  *		EINVAL since we can't deduce hostid part of the address.
479  *	SIOCDLIFADDR: delete the specified address.
480  *	SIOCDLIFADDR with IFLR_PREFIX:
481  *		delete the first address that matches the specified prefix.
482  * return values:
483  *	EINVAL on invalid parameters
484  *	EADDRNOTAVAIL on prefix match failed/specified address not found
485  *	other values may be returned from in_ioctl()
486  */
487 static int
488 in_lifaddr_ioctl(so, cmd, data, ifp, td)
489 	struct socket *so;
490 	u_long cmd;
491 	caddr_t	data;
492 	struct ifnet *ifp;
493 	struct thread *td;
494 {
495 	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
496 	struct ifaddr *ifa;
497 
498 	/* sanity checks */
499 	if (!data || !ifp) {
500 		panic("invalid argument to in_lifaddr_ioctl");
501 		/*NOTRECHED*/
502 	}
503 
504 	switch (cmd) {
505 	case SIOCGLIFADDR:
506 		/* address must be specified on GET with IFLR_PREFIX */
507 		if ((iflr->flags & IFLR_PREFIX) == 0)
508 			break;
509 		/*FALLTHROUGH*/
510 	case SIOCALIFADDR:
511 	case SIOCDLIFADDR:
512 		/* address must be specified on ADD and DELETE */
513 		if (iflr->addr.ss_family != AF_INET)
514 			return EINVAL;
515 		if (iflr->addr.ss_len != sizeof(struct sockaddr_in))
516 			return EINVAL;
517 		/* XXX need improvement */
518 		if (iflr->dstaddr.ss_family
519 		 && iflr->dstaddr.ss_family != AF_INET)
520 			return EINVAL;
521 		if (iflr->dstaddr.ss_family
522 		 && iflr->dstaddr.ss_len != sizeof(struct sockaddr_in))
523 			return EINVAL;
524 		break;
525 	default: /*shouldn't happen*/
526 		return EOPNOTSUPP;
527 	}
528 	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
529 		return EINVAL;
530 
531 	switch (cmd) {
532 	case SIOCALIFADDR:
533 	    {
534 		struct in_aliasreq ifra;
535 
536 		if (iflr->flags & IFLR_PREFIX)
537 			return EINVAL;
538 
539 		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
540 		bzero(&ifra, sizeof(ifra));
541 		bcopy(iflr->iflr_name, ifra.ifra_name,
542 			sizeof(ifra.ifra_name));
543 
544 		bcopy(&iflr->addr, &ifra.ifra_addr, iflr->addr.ss_len);
545 
546 		if (iflr->dstaddr.ss_family) {	/*XXX*/
547 			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
548 				iflr->dstaddr.ss_len);
549 		}
550 
551 		ifra.ifra_mask.sin_family = AF_INET;
552 		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
553 		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
554 
555 		return in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, td);
556 	    }
557 	case SIOCGLIFADDR:
558 	case SIOCDLIFADDR:
559 	    {
560 		struct in_ifaddr *ia;
561 		struct in_addr mask, candidate, match;
562 		struct sockaddr_in *sin;
563 		int cmp;
564 
565 		bzero(&mask, sizeof(mask));
566 		if (iflr->flags & IFLR_PREFIX) {
567 			/* lookup a prefix rather than address. */
568 			in_len2mask(&mask, iflr->prefixlen);
569 
570 			sin = (struct sockaddr_in *)&iflr->addr;
571 			match.s_addr = sin->sin_addr.s_addr;
572 			match.s_addr &= mask.s_addr;
573 
574 			/* if you set extra bits, that's wrong */
575 			if (match.s_addr != sin->sin_addr.s_addr)
576 				return EINVAL;
577 
578 			cmp = 1;
579 		} else {
580 			if (cmd == SIOCGLIFADDR) {
581 				/* on getting an address, take the 1st match */
582 				cmp = 0;	/*XXX*/
583 			} else {
584 				/* on deleting an address, do exact match */
585 				in_len2mask(&mask, 32);
586 				sin = (struct sockaddr_in *)&iflr->addr;
587 				match.s_addr = sin->sin_addr.s_addr;
588 
589 				cmp = 1;
590 			}
591 		}
592 
593 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)	{
594 			if (ifa->ifa_addr->sa_family != AF_INET6)
595 				continue;
596 			if (!cmp)
597 				break;
598 			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
599 			candidate.s_addr &= mask.s_addr;
600 			if (candidate.s_addr == match.s_addr)
601 				break;
602 		}
603 		if (!ifa)
604 			return EADDRNOTAVAIL;
605 		ia = (struct in_ifaddr *)ifa;
606 
607 		if (cmd == SIOCGLIFADDR) {
608 			/* fill in the if_laddrreq structure */
609 			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
610 
611 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
612 				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
613 					ia->ia_dstaddr.sin_len);
614 			} else
615 				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
616 
617 			iflr->prefixlen =
618 				in_mask2len(&ia->ia_sockmask.sin_addr);
619 
620 			iflr->flags = 0;	/*XXX*/
621 
622 			return 0;
623 		} else {
624 			struct in_aliasreq ifra;
625 
626 			/* fill in_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
627 			bzero(&ifra, sizeof(ifra));
628 			bcopy(iflr->iflr_name, ifra.ifra_name,
629 				sizeof(ifra.ifra_name));
630 
631 			bcopy(&ia->ia_addr, &ifra.ifra_addr,
632 				ia->ia_addr.sin_len);
633 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
634 				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
635 					ia->ia_dstaddr.sin_len);
636 			}
637 			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
638 				ia->ia_sockmask.sin_len);
639 
640 			return in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
641 					  ifp, td);
642 		}
643 	    }
644 	}
645 
646 	return EOPNOTSUPP;	/*just for safety*/
647 }
648 
649 /*
650  * Delete any existing route for an interface.
651  */
652 void
653 in_ifscrub(ifp, ia)
654 	register struct ifnet *ifp;
655 	register struct in_ifaddr *ia;
656 {
657 
658 	if ((ia->ia_flags & IFA_ROUTE) == 0)
659 		return;
660 	if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
661 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
662 	else
663 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
664 	ia->ia_flags &= ~IFA_ROUTE;
665 }
666 
667 /*
668  * Initialize an interface's internet address
669  * and routing table entry.
670  */
671 static int
672 in_ifinit(ifp, ia, sin, scrub)
673 	register struct ifnet *ifp;
674 	register struct in_ifaddr *ia;
675 	struct sockaddr_in *sin;
676 	int scrub;
677 {
678 	register u_long i = ntohl(sin->sin_addr.s_addr);
679 	struct sockaddr_in oldaddr;
680 	int s = splimp(), flags = RTF_UP, error = 0;
681 
682 	oldaddr = ia->ia_addr;
683 	if (oldaddr.sin_family == AF_INET)
684 		LIST_REMOVE(ia, ia_hash);
685 	ia->ia_addr = *sin;
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 	/*
690 	 * Give the interface a chance to initialize
691 	 * if this is its first address,
692 	 * and to validate the address if necessary.
693 	 */
694 	if (ifp->if_ioctl &&
695 	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
696 		splx(s);
697 		/* LIST_REMOVE(ia, ia_hash) is done in in_control */
698 		ia->ia_addr = oldaddr;
699 		if (ia->ia_addr.sin_family == AF_INET)
700 			LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
701 			    ia, ia_hash);
702 		return (error);
703 	}
704 	splx(s);
705 	if (scrub) {
706 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
707 		in_ifscrub(ifp, ia);
708 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
709 	}
710 	if (IN_CLASSA(i))
711 		ia->ia_netmask = IN_CLASSA_NET;
712 	else if (IN_CLASSB(i))
713 		ia->ia_netmask = IN_CLASSB_NET;
714 	else
715 		ia->ia_netmask = IN_CLASSC_NET;
716 	/*
717 	 * The subnet mask usually includes at least the standard network part,
718 	 * but may may be smaller in the case of supernetting.
719 	 * If it is set, we believe it.
720 	 */
721 	if (ia->ia_subnetmask == 0) {
722 		ia->ia_subnetmask = ia->ia_netmask;
723 		ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
724 	} else
725 		ia->ia_netmask &= ia->ia_subnetmask;
726 	ia->ia_net = i & ia->ia_netmask;
727 	ia->ia_subnet = i & ia->ia_subnetmask;
728 	in_socktrim(&ia->ia_sockmask);
729 	/*
730 	 * Add route for the network.
731 	 */
732 	ia->ia_ifa.ifa_metric = ifp->if_metric;
733 	if (ifp->if_flags & IFF_BROADCAST) {
734 		ia->ia_broadaddr.sin_addr.s_addr =
735 			htonl(ia->ia_subnet | ~ia->ia_subnetmask);
736 		ia->ia_netbroadcast.s_addr =
737 			htonl(ia->ia_net | ~ ia->ia_netmask);
738 	} else if (ifp->if_flags & IFF_LOOPBACK) {
739 		ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
740 		flags |= RTF_HOST;
741 	} else if (ifp->if_flags & IFF_POINTOPOINT) {
742 		if (ia->ia_dstaddr.sin_family != AF_INET)
743 			return (0);
744 		flags |= RTF_HOST;
745 	}
746 
747 	/*-
748 	 * Don't add host routes for interface addresses of
749 	 * 0.0.0.0 --> 0.255.255.255 netmask 255.0.0.0.  This makes it
750 	 * possible to assign several such address pairs with consistent
751 	 * results (no host route) and is required by BOOTP.
752 	 *
753 	 * XXX: This is ugly !  There should be a way for the caller to
754 	 *      say that they don't want a host route.
755 	 */
756 	if (ia->ia_addr.sin_addr.s_addr != INADDR_ANY ||
757 	    ia->ia_netmask != IN_CLASSA_NET ||
758 	    ia->ia_dstaddr.sin_addr.s_addr != htonl(IN_CLASSA_HOST)) {
759 		if ((error = rtinit(&ia->ia_ifa, (int)RTM_ADD, flags)) != 0) {
760 			ia->ia_addr = oldaddr;
761 			return (error);
762 		}
763 		ia->ia_flags |= IFA_ROUTE;
764 	}
765 
766 	/*
767 	 * If the interface supports multicast, join the "all hosts"
768 	 * multicast group on that interface.
769 	 */
770 	if (ifp->if_flags & IFF_MULTICAST) {
771 		struct in_addr addr;
772 
773 		addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
774 		in_addmulti(&addr, ifp);
775 	}
776 	return (error);
777 }
778 
779 
780 /*
781  * Return 1 if the address might be a local broadcast address.
782  */
783 int
784 in_broadcast(in, ifp)
785 	struct in_addr in;
786         struct ifnet *ifp;
787 {
788 	register struct ifaddr *ifa;
789 	u_long t;
790 
791 	if (in.s_addr == INADDR_BROADCAST ||
792 	    in.s_addr == INADDR_ANY)
793 		return 1;
794 	if ((ifp->if_flags & IFF_BROADCAST) == 0)
795 		return 0;
796 	t = ntohl(in.s_addr);
797 	/*
798 	 * Look through the list of addresses for a match
799 	 * with a broadcast address.
800 	 */
801 #define ia ((struct in_ifaddr *)ifa)
802 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
803 		if (ifa->ifa_addr->sa_family == AF_INET &&
804 		    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
805 		     in.s_addr == ia->ia_netbroadcast.s_addr ||
806 		     /*
807 		      * Check for old-style (host 0) broadcast.
808 		      */
809 		     t == ia->ia_subnet || t == ia->ia_net) &&
810 		     /*
811 		      * Check for an all one subnetmask. These
812 		      * only exist when an interface gets a secondary
813 		      * address.
814 		      */
815 		     ia->ia_subnetmask != (u_long)0xffffffff)
816 			    return 1;
817 	return (0);
818 #undef ia
819 }
820 /*
821  * Add an address to the list of IP multicast addresses for a given interface.
822  */
823 struct in_multi *
824 in_addmulti(ap, ifp)
825 	register struct in_addr *ap;
826 	register struct ifnet *ifp;
827 {
828 	register struct in_multi *inm;
829 	int error;
830 	struct sockaddr_in sin;
831 	struct ifmultiaddr *ifma;
832 	int s = splnet();
833 
834 	/*
835 	 * Call generic routine to add membership or increment
836 	 * refcount.  It wants addresses in the form of a sockaddr,
837 	 * so we build one here (being careful to zero the unused bytes).
838 	 */
839 	bzero(&sin, sizeof sin);
840 	sin.sin_family = AF_INET;
841 	sin.sin_len = sizeof sin;
842 	sin.sin_addr = *ap;
843 	error = if_addmulti(ifp, (struct sockaddr *)&sin, &ifma);
844 	if (error) {
845 		splx(s);
846 		return 0;
847 	}
848 
849 	/*
850 	 * If ifma->ifma_protospec is null, then if_addmulti() created
851 	 * a new record.  Otherwise, we are done.
852 	 */
853 	if (ifma->ifma_protospec != 0) {
854 		splx(s);
855 		return ifma->ifma_protospec;
856 	}
857 
858 	/* XXX - if_addmulti uses M_WAITOK.  Can this really be called
859 	   at interrupt time?  If so, need to fix if_addmulti. XXX */
860 	inm = (struct in_multi *)malloc(sizeof(*inm), M_IPMADDR,
861 	    M_NOWAIT | M_ZERO);
862 	if (inm == NULL) {
863 		splx(s);
864 		return (NULL);
865 	}
866 
867 	inm->inm_addr = *ap;
868 	inm->inm_ifp = ifp;
869 	inm->inm_ifma = ifma;
870 	ifma->ifma_protospec = inm;
871 	LIST_INSERT_HEAD(&in_multihead, inm, inm_link);
872 
873 	/*
874 	 * Let IGMP know that we have joined a new IP multicast group.
875 	 */
876 	igmp_joingroup(inm);
877 	splx(s);
878 	return (inm);
879 }
880 
881 /*
882  * Delete a multicast address record.
883  */
884 void
885 in_delmulti(inm)
886 	register struct in_multi *inm;
887 {
888 	struct ifmultiaddr *ifma = inm->inm_ifma;
889 	struct in_multi my_inm;
890 	int s = splnet();
891 
892 	my_inm.inm_ifp = NULL ; /* don't send the leave msg */
893 	if (ifma->ifma_refcount == 1) {
894 		/*
895 		 * No remaining claims to this record; let IGMP know that
896 		 * we are leaving the multicast group.
897 		 * But do it after the if_delmulti() which might reset
898 		 * the interface and nuke the packet.
899 		 */
900 		my_inm = *inm ;
901 		ifma->ifma_protospec = 0;
902 		LIST_REMOVE(inm, inm_link);
903 		free(inm, M_IPMADDR);
904 	}
905 	/* XXX - should be separate API for when we have an ifma? */
906 	if_delmulti(ifma->ifma_ifp, ifma->ifma_addr);
907 	if (my_inm.inm_ifp != NULL)
908 		igmp_leavegroup(&my_inm);
909 	splx(s);
910 }
911