xref: /freebsd/sys/netinet/in.c (revision cb166ce422ac2bc81f42c2a2e2cd68625c11478d)
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/proc.h>
42 #include <sys/socket.h>
43 #include <sys/kernel.h>
44 #include <sys/sysctl.h>
45 
46 #include <net/if.h>
47 #include <net/if_types.h>
48 #include <net/route.h>
49 
50 #include <netinet/in.h>
51 #include <netinet/in_var.h>
52 
53 #include <netinet/igmp_var.h>
54 
55 #include "gif.h"
56 #if NGIF > 0
57 #include <net/if_gif.h>
58 #endif
59 
60 static MALLOC_DEFINE(M_IPMADDR, "in_multi", "internet multicast address");
61 
62 static int in_mask2len __P((struct in_addr *));
63 static void in_len2mask __P((struct in_addr *, int));
64 static int in_lifaddr_ioctl __P((struct socket *, u_long, caddr_t,
65 	struct ifnet *, struct proc *));
66 
67 static void	in_socktrim __P((struct sockaddr_in *));
68 static int	in_ifinit __P((struct ifnet *,
69 	    struct in_ifaddr *, struct sockaddr_in *, int));
70 
71 static int subnetsarelocal = 0;
72 SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW,
73 	&subnetsarelocal, 0, "");
74 
75 struct in_multihead in_multihead; /* XXX BSS initialization */
76 
77 /*
78  * Return 1 if an internet address is for a ``local'' host
79  * (one to which we have a connection).  If subnetsarelocal
80  * is true, this includes other subnets of the local net.
81  * Otherwise, it includes only the directly-connected (sub)nets.
82  */
83 int
84 in_localaddr(in)
85 	struct in_addr in;
86 {
87 	register u_long i = ntohl(in.s_addr);
88 	register struct in_ifaddr *ia;
89 
90 	if (subnetsarelocal) {
91 		for (ia = in_ifaddrhead.tqh_first; ia;
92 		     ia = ia->ia_link.tqe_next)
93 			if ((i & ia->ia_netmask) == ia->ia_net)
94 				return (1);
95 	} else {
96 		for (ia = in_ifaddrhead.tqh_first; ia;
97 		     ia = ia->ia_link.tqe_next)
98 			if ((i & ia->ia_subnetmask) == ia->ia_subnet)
99 				return (1);
100 	}
101 	return (0);
102 }
103 
104 /*
105  * Determine whether an IP address is in a reserved set of addresses
106  * that may not be forwarded, or whether datagrams to that destination
107  * may be forwarded.
108  */
109 int
110 in_canforward(in)
111 	struct in_addr in;
112 {
113 	register u_long i = ntohl(in.s_addr);
114 	register u_long net;
115 
116 	if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i))
117 		return (0);
118 	if (IN_CLASSA(i)) {
119 		net = i & IN_CLASSA_NET;
120 		if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
121 			return (0);
122 	}
123 	return (1);
124 }
125 
126 /*
127  * Trim a mask in a sockaddr
128  */
129 static void
130 in_socktrim(ap)
131 struct sockaddr_in *ap;
132 {
133     register char *cplim = (char *) &ap->sin_addr;
134     register char *cp = (char *) (&ap->sin_addr + 1);
135 
136     ap->sin_len = 0;
137     while (--cp >= cplim)
138         if (*cp) {
139 	    (ap)->sin_len = cp - (char *) (ap) + 1;
140 	    break;
141 	}
142 }
143 
144 static int
145 in_mask2len(mask)
146 	struct in_addr *mask;
147 {
148 	int x, y;
149 	u_char *p;
150 
151 	p = (u_char *)mask;
152 	for (x = 0; x < sizeof(*mask); x++) {
153 		if (p[x] != 0xff)
154 			break;
155 	}
156 	y = 0;
157 	if (x < sizeof(*mask)) {
158 		for (y = 0; y < 8; y++) {
159 			if ((p[x] & (0x80 >> y)) == 0)
160 				break;
161 		}
162 	}
163 	return x * 8 + y;
164 }
165 
166 static void
167 in_len2mask(mask, len)
168 	struct in_addr *mask;
169 	int len;
170 {
171 	int i;
172 	u_char *p;
173 
174 	p = (u_char *)mask;
175 	bzero(mask, sizeof(*mask));
176 	for (i = 0; i < len / 8; i++)
177 		p[i] = 0xff;
178 	if (len % 8)
179 		p[i] = (0xff00 >> (len % 8)) & 0xff;
180 }
181 
182 static int in_interfaces;	/* number of external internet interfaces */
183 
184 /*
185  * Generic internet control operations (ioctl's).
186  * Ifp is 0 if not an interface-specific ioctl.
187  */
188 /* ARGSUSED */
189 int
190 in_control(so, cmd, data, ifp, p)
191 	struct socket *so;
192 	u_long cmd;
193 	caddr_t data;
194 	register struct ifnet *ifp;
195 	struct proc *p;
196 {
197 	register struct ifreq *ifr = (struct ifreq *)data;
198 	register struct in_ifaddr *ia = 0, *iap;
199 	register struct ifaddr *ifa;
200 	struct in_ifaddr *oia;
201 	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
202 	struct sockaddr_in oldaddr;
203 	int error, hostIsNew, maskIsNew, s;
204 	u_long i;
205 
206 #if NGIF > 0
207         if (ifp && ifp->if_type == IFT_GIF) {
208                 switch (cmd) {
209                 case SIOCSIFPHYADDR:
210 			if (p &&
211 			    (error = suser(p)) != 0)
212         			return(error);
213                 case SIOCGIFPSRCADDR:
214                 case SIOCGIFPDSTADDR:
215                         return gif_ioctl(ifp, cmd, data);
216                 }
217         }
218 #endif
219 
220 	switch (cmd) {
221 	case SIOCALIFADDR:
222 	case SIOCDLIFADDR:
223 		if (p && (error = suser(p)) != 0)
224 			return error;
225 		/*fall through*/
226 	case SIOCGLIFADDR:
227 		if (!ifp)
228 			return EINVAL;
229 		return in_lifaddr_ioctl(so, cmd, data, ifp, p);
230 	}
231 
232 	/*
233 	 * Find address for this interface, if it exists.
234 	 *
235 	 * If an alias address was specified, find that one instead of
236 	 * the first one on the interface.
237 	 */
238 	if (ifp)
239 		for (iap = in_ifaddrhead.tqh_first; iap;
240 		     iap = iap->ia_link.tqe_next)
241 			if (iap->ia_ifp == ifp) {
242 				if (((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr.s_addr ==
243 				    iap->ia_addr.sin_addr.s_addr) {
244 					ia = iap;
245 					break;
246 				} else if (ia == NULL) {
247 					ia = iap;
248 					if (ifr->ifr_addr.sa_family != AF_INET)
249 						break;
250 				}
251 			}
252 
253 	switch (cmd) {
254 
255 	case SIOCAIFADDR:
256 	case SIOCDIFADDR:
257 		if (ifp == 0)
258 			return (EADDRNOTAVAIL);
259 		if (ifra->ifra_addr.sin_family == AF_INET) {
260 			for (oia = ia; ia; ia = ia->ia_link.tqe_next) {
261 				if (ia->ia_ifp == ifp  &&
262 				    ia->ia_addr.sin_addr.s_addr ==
263 				    ifra->ifra_addr.sin_addr.s_addr)
264 					break;
265 			}
266 			if ((ifp->if_flags & IFF_POINTOPOINT)
267 			    && (cmd == SIOCAIFADDR)
268 			    && (ifra->ifra_dstaddr.sin_addr.s_addr
269 				== INADDR_ANY)) {
270 				return EDESTADDRREQ;
271 			}
272 		}
273 		if (cmd == SIOCDIFADDR && ia == 0)
274 			return (EADDRNOTAVAIL);
275 		/* FALLTHROUGH */
276 	case SIOCSIFADDR:
277 	case SIOCSIFNETMASK:
278 	case SIOCSIFDSTADDR:
279 		if (p && (error = suser(p)) != 0)
280 			return error;
281 
282 		if (ifp == 0)
283 			return (EADDRNOTAVAIL);
284 		if (ia == (struct in_ifaddr *)0) {
285 			ia = (struct in_ifaddr *)
286 				malloc(sizeof *ia, M_IFADDR, M_WAITOK);
287 			if (ia == (struct in_ifaddr *)NULL)
288 				return (ENOBUFS);
289 			bzero((caddr_t)ia, sizeof *ia);
290 			/*
291 			 * Protect from ipintr() traversing address list
292 			 * while we're modifying it.
293 			 */
294 			s = splnet();
295 
296 			TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
297 			ifa = &ia->ia_ifa;
298 			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
299 
300 			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
301 			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
302 			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
303 			ia->ia_sockmask.sin_len = 8;
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 			if (!(ifp->if_flags & IFF_LOOPBACK))
310 				in_interfaces++;
311 			splx(s);
312 		}
313 		break;
314 
315 	case SIOCSIFBRDADDR:
316 		if (p && (error = suser(p)) != 0)
317 			return error;
318 		/* FALLTHROUGH */
319 
320 	case SIOCGIFADDR:
321 	case SIOCGIFNETMASK:
322 	case SIOCGIFDSTADDR:
323 	case SIOCGIFBRDADDR:
324 		if (ia == (struct in_ifaddr *)0)
325 			return (EADDRNOTAVAIL);
326 		break;
327 	}
328 	switch (cmd) {
329 
330 	case SIOCGIFADDR:
331 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
332 		break;
333 
334 	case SIOCGIFBRDADDR:
335 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
336 			return (EINVAL);
337 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
338 		break;
339 
340 	case SIOCGIFDSTADDR:
341 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
342 			return (EINVAL);
343 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
344 		break;
345 
346 	case SIOCGIFNETMASK:
347 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
348 		break;
349 
350 	case SIOCSIFDSTADDR:
351 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
352 			return (EINVAL);
353 		oldaddr = ia->ia_dstaddr;
354 		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
355 		if (ifp->if_ioctl && (error = (*ifp->if_ioctl)
356 					(ifp, SIOCSIFDSTADDR, (caddr_t)ia))) {
357 			ia->ia_dstaddr = oldaddr;
358 			return (error);
359 		}
360 		if (ia->ia_flags & IFA_ROUTE) {
361 			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
362 			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
363 			ia->ia_ifa.ifa_dstaddr =
364 					(struct sockaddr *)&ia->ia_dstaddr;
365 			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
366 		}
367 		break;
368 
369 	case SIOCSIFBRDADDR:
370 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
371 			return (EINVAL);
372 		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
373 		break;
374 
375 	case SIOCSIFADDR:
376 		return (in_ifinit(ifp, ia,
377 		    (struct sockaddr_in *) &ifr->ifr_addr, 1));
378 
379 	case SIOCSIFNETMASK:
380 		i = ifra->ifra_addr.sin_addr.s_addr;
381 		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr = i);
382 		break;
383 
384 	case SIOCAIFADDR:
385 		maskIsNew = 0;
386 		hostIsNew = 1;
387 		error = 0;
388 		if (ia->ia_addr.sin_family == AF_INET) {
389 			if (ifra->ifra_addr.sin_len == 0) {
390 				ifra->ifra_addr = ia->ia_addr;
391 				hostIsNew = 0;
392 			} else if (ifra->ifra_addr.sin_addr.s_addr ==
393 					       ia->ia_addr.sin_addr.s_addr)
394 				hostIsNew = 0;
395 		}
396 		if (ifra->ifra_mask.sin_len) {
397 			in_ifscrub(ifp, ia);
398 			ia->ia_sockmask = ifra->ifra_mask;
399 			ia->ia_subnetmask =
400 			     ntohl(ia->ia_sockmask.sin_addr.s_addr);
401 			maskIsNew = 1;
402 		}
403 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
404 		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
405 			in_ifscrub(ifp, ia);
406 			ia->ia_dstaddr = ifra->ifra_dstaddr;
407 			maskIsNew  = 1; /* We lie; but the effect's the same */
408 		}
409 		if (ifra->ifra_addr.sin_family == AF_INET &&
410 		    (hostIsNew || maskIsNew))
411 			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
412 		if ((ifp->if_flags & IFF_BROADCAST) &&
413 		    (ifra->ifra_broadaddr.sin_family == AF_INET))
414 			ia->ia_broadaddr = ifra->ifra_broadaddr;
415 		return (error);
416 
417 	case SIOCDIFADDR:
418 		in_ifscrub(ifp, ia);
419 		/*
420 		 * Protect from ipintr() traversing address list
421 		 * while we're modifying it.
422 		 */
423 		s = splnet();
424 
425 		ifa = &ia->ia_ifa;
426 		TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
427 		oia = ia;
428 		TAILQ_REMOVE(&in_ifaddrhead, oia, ia_link);
429 		IFAFREE(&oia->ia_ifa);
430 		splx(s);
431 		break;
432 
433 	default:
434 		if (ifp == 0 || ifp->if_ioctl == 0)
435 			return (EOPNOTSUPP);
436 		return ((*ifp->if_ioctl)(ifp, cmd, data));
437 	}
438 	return (0);
439 }
440 
441 /*
442  * SIOC[GAD]LIFADDR.
443  *	SIOCGLIFADDR: get first address. (?!?)
444  *	SIOCGLIFADDR with IFLR_PREFIX:
445  *		get first address that matches the specified prefix.
446  *	SIOCALIFADDR: add the specified address.
447  *	SIOCALIFADDR with IFLR_PREFIX:
448  *		EINVAL since we can't deduce hostid part of the address.
449  *	SIOCDLIFADDR: delete the specified address.
450  *	SIOCDLIFADDR with IFLR_PREFIX:
451  *		delete the first address that matches the specified prefix.
452  * return values:
453  *	EINVAL on invalid parameters
454  *	EADDRNOTAVAIL on prefix match failed/specified address not found
455  *	other values may be returned from in_ioctl()
456  */
457 static int
458 in_lifaddr_ioctl(so, cmd, data, ifp, p)
459 	struct socket *so;
460 	u_long cmd;
461 	caddr_t	data;
462 	struct ifnet *ifp;
463 	struct proc *p;
464 {
465 	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
466 	struct ifaddr *ifa;
467 
468 	/* sanity checks */
469 	if (!data || !ifp) {
470 		panic("invalid argument to in_lifaddr_ioctl");
471 		/*NOTRECHED*/
472 	}
473 
474 	switch (cmd) {
475 	case SIOCGLIFADDR:
476 		/* address must be specified on GET with IFLR_PREFIX */
477 		if ((iflr->flags & IFLR_PREFIX) == 0)
478 			break;
479 		/*FALLTHROUGH*/
480 	case SIOCALIFADDR:
481 	case SIOCDLIFADDR:
482 		/* address must be specified on ADD and DELETE */
483 		if (iflr->addr.ss_family != AF_INET)
484 			return EINVAL;
485 		if (iflr->addr.ss_len != sizeof(struct sockaddr_in))
486 			return EINVAL;
487 		/* XXX need improvement */
488 		if (iflr->dstaddr.ss_family
489 		 && iflr->dstaddr.ss_family != AF_INET)
490 			return EINVAL;
491 		if (iflr->dstaddr.ss_family
492 		 && iflr->dstaddr.ss_len != sizeof(struct sockaddr_in))
493 			return EINVAL;
494 		break;
495 	default: /*shouldn't happen*/
496 		return EOPNOTSUPP;
497 	}
498 	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
499 		return EINVAL;
500 
501 	switch (cmd) {
502 	case SIOCALIFADDR:
503 	    {
504 		struct in_aliasreq ifra;
505 
506 		if (iflr->flags & IFLR_PREFIX)
507 			return EINVAL;
508 
509 		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
510 		bzero(&ifra, sizeof(ifra));
511 		bcopy(iflr->iflr_name, ifra.ifra_name,
512 			sizeof(ifra.ifra_name));
513 
514 		bcopy(&iflr->addr, &ifra.ifra_addr, iflr->addr.ss_len);
515 
516 		if (iflr->dstaddr.ss_family) {	/*XXX*/
517 			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
518 				iflr->dstaddr.ss_len);
519 		}
520 
521 		ifra.ifra_mask.sin_family = AF_INET;
522 		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
523 		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
524 
525 		return in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, p);
526 	    }
527 	case SIOCGLIFADDR:
528 	case SIOCDLIFADDR:
529 	    {
530 		struct in_ifaddr *ia;
531 		struct in_addr mask, candidate, match;
532 		struct sockaddr_in *sin;
533 		int cmp;
534 
535 		bzero(&mask, sizeof(mask));
536 		if (iflr->flags & IFLR_PREFIX) {
537 			/* lookup a prefix rather than address. */
538 			in_len2mask(&mask, iflr->prefixlen);
539 
540 			sin = (struct sockaddr_in *)&iflr->addr;
541 			match.s_addr = sin->sin_addr.s_addr;
542 			match.s_addr &= mask.s_addr;
543 
544 			/* if you set extra bits, that's wrong */
545 			if (match.s_addr != sin->sin_addr.s_addr)
546 				return EINVAL;
547 
548 			cmp = 1;
549 		} else {
550 			if (cmd == SIOCGLIFADDR) {
551 				/* on getting an address, take the 1st match */
552 				cmp = 0;	/*XXX*/
553 			} else {
554 				/* on deleting an address, do exact match */
555 				in_len2mask(&mask, 32);
556 				sin = (struct sockaddr_in *)&iflr->addr;
557 				match.s_addr = sin->sin_addr.s_addr;
558 
559 				cmp = 1;
560 			}
561 		}
562 
563 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)	{
564 			if (ifa->ifa_addr->sa_family != AF_INET6)
565 				continue;
566 			if (!cmp)
567 				break;
568 			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
569 			candidate.s_addr &= mask.s_addr;
570 			if (candidate.s_addr == match.s_addr)
571 				break;
572 		}
573 		if (!ifa)
574 			return EADDRNOTAVAIL;
575 		ia = (struct in_ifaddr *)ifa;
576 
577 		if (cmd == SIOCGLIFADDR) {
578 			/* fill in the if_laddrreq structure */
579 			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
580 
581 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
582 				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
583 					ia->ia_dstaddr.sin_len);
584 			} else
585 				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
586 
587 			iflr->prefixlen =
588 				in_mask2len(&ia->ia_sockmask.sin_addr);
589 
590 			iflr->flags = 0;	/*XXX*/
591 
592 			return 0;
593 		} else {
594 			struct in_aliasreq ifra;
595 
596 			/* fill in_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
597 			bzero(&ifra, sizeof(ifra));
598 			bcopy(iflr->iflr_name, ifra.ifra_name,
599 				sizeof(ifra.ifra_name));
600 
601 			bcopy(&ia->ia_addr, &ifra.ifra_addr,
602 				ia->ia_addr.sin_len);
603 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
604 				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
605 					ia->ia_dstaddr.sin_len);
606 			}
607 			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
608 				ia->ia_sockmask.sin_len);
609 
610 			return in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
611 					  ifp, p);
612 		}
613 	    }
614 	}
615 
616 	return EOPNOTSUPP;	/*just for safety*/
617 }
618 
619 /*
620  * Delete any existing route for an interface.
621  */
622 void
623 in_ifscrub(ifp, ia)
624 	register struct ifnet *ifp;
625 	register struct in_ifaddr *ia;
626 {
627 
628 	if ((ia->ia_flags & IFA_ROUTE) == 0)
629 		return;
630 	if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
631 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
632 	else
633 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
634 	ia->ia_flags &= ~IFA_ROUTE;
635 }
636 
637 /*
638  * Initialize an interface's internet address
639  * and routing table entry.
640  */
641 static int
642 in_ifinit(ifp, ia, sin, scrub)
643 	register struct ifnet *ifp;
644 	register struct in_ifaddr *ia;
645 	struct sockaddr_in *sin;
646 	int scrub;
647 {
648 	register u_long i = ntohl(sin->sin_addr.s_addr);
649 	struct sockaddr_in oldaddr;
650 	int s = splimp(), flags = RTF_UP, error;
651 
652 	oldaddr = ia->ia_addr;
653 	ia->ia_addr = *sin;
654 	/*
655 	 * Give the interface a chance to initialize
656 	 * if this is its first address,
657 	 * and to validate the address if necessary.
658 	 */
659 	if (ifp->if_ioctl &&
660 	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
661 		splx(s);
662 		ia->ia_addr = oldaddr;
663 		return (error);
664 	}
665 	splx(s);
666 	if (scrub) {
667 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
668 		in_ifscrub(ifp, ia);
669 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
670 	}
671 	if (IN_CLASSA(i))
672 		ia->ia_netmask = IN_CLASSA_NET;
673 	else if (IN_CLASSB(i))
674 		ia->ia_netmask = IN_CLASSB_NET;
675 	else
676 		ia->ia_netmask = IN_CLASSC_NET;
677 	/*
678 	 * The subnet mask usually includes at least the standard network part,
679 	 * but may may be smaller in the case of supernetting.
680 	 * If it is set, we believe it.
681 	 */
682 	if (ia->ia_subnetmask == 0) {
683 		ia->ia_subnetmask = ia->ia_netmask;
684 		ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
685 	} else
686 		ia->ia_netmask &= ia->ia_subnetmask;
687 	ia->ia_net = i & ia->ia_netmask;
688 	ia->ia_subnet = i & ia->ia_subnetmask;
689 	in_socktrim(&ia->ia_sockmask);
690 	/*
691 	 * Add route for the network.
692 	 */
693 	ia->ia_ifa.ifa_metric = ifp->if_metric;
694 	if (ifp->if_flags & IFF_BROADCAST) {
695 		ia->ia_broadaddr.sin_addr.s_addr =
696 			htonl(ia->ia_subnet | ~ia->ia_subnetmask);
697 		ia->ia_netbroadcast.s_addr =
698 			htonl(ia->ia_net | ~ ia->ia_netmask);
699 	} else if (ifp->if_flags & IFF_LOOPBACK) {
700 		ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
701 		flags |= RTF_HOST;
702 	} else if (ifp->if_flags & IFF_POINTOPOINT) {
703 		if (ia->ia_dstaddr.sin_family != AF_INET)
704 			return (0);
705 		flags |= RTF_HOST;
706 	}
707 	if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD, flags)) == 0)
708 		ia->ia_flags |= IFA_ROUTE;
709 
710 	/*
711 	 * If the interface supports multicast, join the "all hosts"
712 	 * multicast group on that interface.
713 	 */
714 	if (ifp->if_flags & IFF_MULTICAST) {
715 		struct in_addr addr;
716 
717 		addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
718 		in_addmulti(&addr, ifp);
719 	}
720 	return (error);
721 }
722 
723 
724 /*
725  * Return 1 if the address might be a local broadcast address.
726  */
727 int
728 in_broadcast(in, ifp)
729 	struct in_addr in;
730         struct ifnet *ifp;
731 {
732 	register struct ifaddr *ifa;
733 	u_long t;
734 
735 	if (in.s_addr == INADDR_BROADCAST ||
736 	    in.s_addr == INADDR_ANY)
737 		return 1;
738 	if ((ifp->if_flags & IFF_BROADCAST) == 0)
739 		return 0;
740 	t = ntohl(in.s_addr);
741 	/*
742 	 * Look through the list of addresses for a match
743 	 * with a broadcast address.
744 	 */
745 #define ia ((struct in_ifaddr *)ifa)
746 	for (ifa = ifp->if_addrhead.tqh_first; ifa;
747 	     ifa = ifa->ifa_link.tqe_next)
748 		if (ifa->ifa_addr->sa_family == AF_INET &&
749 		    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
750 		     in.s_addr == ia->ia_netbroadcast.s_addr ||
751 		     /*
752 		      * Check for old-style (host 0) broadcast.
753 		      */
754 		     t == ia->ia_subnet || t == ia->ia_net) &&
755 		     /*
756 		      * Check for an all one subnetmask. These
757 		      * only exist when an interface gets a secondary
758 		      * address.
759 		      */
760 		     ia->ia_subnetmask != (u_long)0xffffffff)
761 			    return 1;
762 	return (0);
763 #undef ia
764 }
765 /*
766  * Add an address to the list of IP multicast addresses for a given interface.
767  */
768 struct in_multi *
769 in_addmulti(ap, ifp)
770 	register struct in_addr *ap;
771 	register struct ifnet *ifp;
772 {
773 	register struct in_multi *inm;
774 	int error;
775 	struct sockaddr_in sin;
776 	struct ifmultiaddr *ifma;
777 	int s = splnet();
778 
779 	/*
780 	 * Call generic routine to add membership or increment
781 	 * refcount.  It wants addresses in the form of a sockaddr,
782 	 * so we build one here (being careful to zero the unused bytes).
783 	 */
784 	bzero(&sin, sizeof sin);
785 	sin.sin_family = AF_INET;
786 	sin.sin_len = sizeof sin;
787 	sin.sin_addr = *ap;
788 	error = if_addmulti(ifp, (struct sockaddr *)&sin, &ifma);
789 	if (error) {
790 		splx(s);
791 		return 0;
792 	}
793 
794 	/*
795 	 * If ifma->ifma_protospec is null, then if_addmulti() created
796 	 * a new record.  Otherwise, we are done.
797 	 */
798 	if (ifma->ifma_protospec != 0)
799 		return ifma->ifma_protospec;
800 
801 	/* XXX - if_addmulti uses M_WAITOK.  Can this really be called
802 	   at interrupt time?  If so, need to fix if_addmulti. XXX */
803 	inm = (struct in_multi *)malloc(sizeof(*inm), M_IPMADDR, M_NOWAIT);
804 	if (inm == NULL) {
805 		splx(s);
806 		return (NULL);
807 	}
808 
809 	bzero(inm, sizeof *inm);
810 	inm->inm_addr = *ap;
811 	inm->inm_ifp = ifp;
812 	inm->inm_ifma = ifma;
813 	ifma->ifma_protospec = inm;
814 	LIST_INSERT_HEAD(&in_multihead, inm, inm_link);
815 
816 	/*
817 	 * Let IGMP know that we have joined a new IP multicast group.
818 	 */
819 	igmp_joingroup(inm);
820 	splx(s);
821 	return (inm);
822 }
823 
824 /*
825  * Delete a multicast address record.
826  */
827 void
828 in_delmulti(inm)
829 	register struct in_multi *inm;
830 {
831 	struct ifmultiaddr *ifma = inm->inm_ifma;
832 	struct in_multi my_inm;
833 	int s = splnet();
834 
835 	my_inm.inm_ifp = NULL ; /* don't send the leave msg */
836 	if (ifma->ifma_refcount == 1) {
837 		/*
838 		 * No remaining claims to this record; let IGMP know that
839 		 * we are leaving the multicast group.
840 		 * But do it after the if_delmulti() which might reset
841 		 * the interface and nuke the packet.
842 		 */
843 		my_inm = *inm ;
844 		ifma->ifma_protospec = 0;
845 		LIST_REMOVE(inm, inm_link);
846 		free(inm, M_IPMADDR);
847 	}
848 	/* XXX - should be separate API for when we have an ifma? */
849 	if_delmulti(ifma->ifma_ifp, ifma->ifma_addr);
850 	if (my_inm.inm_ifp != NULL)
851 		igmp_leavegroup(&my_inm);
852 	splx(s);
853 }
854