xref: /freebsd/sys/netinet/in.c (revision ee41f1b1cf5e3d4f586cb85b46123b416275862c)
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 
52 #include <netinet/igmp_var.h>
53 
54 #include "gif.h"
55 #if NGIF > 0
56 #include <net/if_gif.h>
57 #endif
58 
59 static MALLOC_DEFINE(M_IPMADDR, "in_multi", "internet multicast address");
60 
61 static int in_mask2len __P((struct in_addr *));
62 static void in_len2mask __P((struct in_addr *, int));
63 static int in_lifaddr_ioctl __P((struct socket *, u_long, caddr_t,
64 	struct ifnet *, struct proc *));
65 
66 static void	in_socktrim __P((struct sockaddr_in *));
67 static int	in_ifinit __P((struct ifnet *,
68 	    struct in_ifaddr *, struct sockaddr_in *, int));
69 
70 static int subnetsarelocal = 0;
71 SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW,
72 	&subnetsarelocal, 0, "");
73 
74 struct in_multihead in_multihead; /* XXX BSS initialization */
75 
76 /*
77  * Return 1 if an internet address is for a ``local'' host
78  * (one to which we have a connection).  If subnetsarelocal
79  * is true, this includes other subnets of the local net.
80  * Otherwise, it includes only the directly-connected (sub)nets.
81  */
82 int
83 in_localaddr(in)
84 	struct in_addr in;
85 {
86 	register u_long i = ntohl(in.s_addr);
87 	register struct in_ifaddr *ia;
88 
89 	if (subnetsarelocal) {
90 		for (ia = TAILQ_FIRST(&in_ifaddrhead); ia;
91 		     ia = TAILQ_NEXT(ia, ia_link))
92 			if ((i & ia->ia_netmask) == ia->ia_net)
93 				return (1);
94 	} else {
95 		TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link)
96 			if ((i & ia->ia_subnetmask) == ia->ia_subnet)
97 				return (1);
98 	}
99 	return (0);
100 }
101 
102 /*
103  * Determine whether an IP address is in a reserved set of addresses
104  * that may not be forwarded, or whether datagrams to that destination
105  * may be forwarded.
106  */
107 int
108 in_canforward(in)
109 	struct in_addr in;
110 {
111 	register u_long i = ntohl(in.s_addr);
112 	register u_long net;
113 
114 	if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i))
115 		return (0);
116 	if (IN_CLASSA(i)) {
117 		net = i & IN_CLASSA_NET;
118 		if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
119 			return (0);
120 	}
121 	return (1);
122 }
123 
124 /*
125  * Trim a mask in a sockaddr
126  */
127 static void
128 in_socktrim(ap)
129 struct sockaddr_in *ap;
130 {
131     register char *cplim = (char *) &ap->sin_addr;
132     register char *cp = (char *) (&ap->sin_addr + 1);
133 
134     ap->sin_len = 0;
135     while (--cp >= cplim)
136         if (*cp) {
137 	    (ap)->sin_len = cp - (char *) (ap) + 1;
138 	    break;
139 	}
140 }
141 
142 static int
143 in_mask2len(mask)
144 	struct in_addr *mask;
145 {
146 	int x, y;
147 	u_char *p;
148 
149 	p = (u_char *)mask;
150 	for (x = 0; x < sizeof(*mask); x++) {
151 		if (p[x] != 0xff)
152 			break;
153 	}
154 	y = 0;
155 	if (x < sizeof(*mask)) {
156 		for (y = 0; y < 8; y++) {
157 			if ((p[x] & (0x80 >> y)) == 0)
158 				break;
159 		}
160 	}
161 	return x * 8 + y;
162 }
163 
164 static void
165 in_len2mask(mask, len)
166 	struct in_addr *mask;
167 	int len;
168 {
169 	int i;
170 	u_char *p;
171 
172 	p = (u_char *)mask;
173 	bzero(mask, sizeof(*mask));
174 	for (i = 0; i < len / 8; i++)
175 		p[i] = 0xff;
176 	if (len % 8)
177 		p[i] = (0xff00 >> (len % 8)) & 0xff;
178 }
179 
180 static int in_interfaces;	/* number of external internet interfaces */
181 
182 /*
183  * Generic internet control operations (ioctl's).
184  * Ifp is 0 if not an interface-specific ioctl.
185  */
186 /* ARGSUSED */
187 int
188 in_control(so, cmd, data, ifp, p)
189 	struct socket *so;
190 	u_long cmd;
191 	caddr_t data;
192 	register struct ifnet *ifp;
193 	struct proc *p;
194 {
195 	register struct ifreq *ifr = (struct ifreq *)data;
196 	register struct in_ifaddr *ia = 0, *iap;
197 	register struct ifaddr *ifa;
198 	struct in_ifaddr *oia;
199 	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
200 	struct sockaddr_in oldaddr;
201 	int error, hostIsNew, maskIsNew, s;
202 	u_long i;
203 
204 #if NGIF > 0
205         if (ifp && ifp->if_type == IFT_GIF) {
206                 switch (cmd) {
207                 case SIOCSIFPHYADDR:
208 		case SIOCDIFPHYADDR:
209 			if (p &&
210 			    (error = suser(p)) != 0)
211         			return(error);
212                 case SIOCGIFPSRCADDR:
213                 case SIOCGIFPDSTADDR:
214                         return gif_ioctl(ifp, cmd, data);
215                 }
216         }
217 #endif
218 
219 	switch (cmd) {
220 	case SIOCALIFADDR:
221 	case SIOCDLIFADDR:
222 		if (p && (error = suser(p)) != 0)
223 			return error;
224 		/*fall through*/
225 	case SIOCGLIFADDR:
226 		if (!ifp)
227 			return EINVAL;
228 		return in_lifaddr_ioctl(so, cmd, data, ifp, p);
229 	}
230 
231 	/*
232 	 * Find address for this interface, if it exists.
233 	 *
234 	 * If an alias address was specified, find that one instead of
235 	 * the first one on the interface.
236 	 */
237 	if (ifp)
238 		for (iap = TAILQ_FIRST(&in_ifaddrhead); iap;
239 		     iap = TAILQ_NEXT(iap, ia_link))
240 			if (iap->ia_ifp == ifp) {
241 				if (((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr.s_addr ==
242 				    iap->ia_addr.sin_addr.s_addr) {
243 					ia = iap;
244 					break;
245 				} else if (ia == NULL) {
246 					ia = iap;
247 					if (ifr->ifr_addr.sa_family != AF_INET)
248 						break;
249 				}
250 			}
251 
252 	switch (cmd) {
253 
254 	case SIOCAIFADDR:
255 	case SIOCDIFADDR:
256 		if (ifp == 0)
257 			return (EADDRNOTAVAIL);
258 		if (ifra->ifra_addr.sin_family == AF_INET) {
259 			for (oia = ia; ia; ia = TAILQ_NEXT(ia, ia_link)) {
260 				if (ia->ia_ifp == ifp  &&
261 				    ia->ia_addr.sin_addr.s_addr ==
262 				    ifra->ifra_addr.sin_addr.s_addr)
263 					break;
264 			}
265 			if ((ifp->if_flags & IFF_POINTOPOINT)
266 			    && (cmd == SIOCAIFADDR)
267 			    && (ifra->ifra_dstaddr.sin_addr.s_addr
268 				== INADDR_ANY)) {
269 				return EDESTADDRREQ;
270 			}
271 		}
272 		if (cmd == SIOCDIFADDR && ia == 0)
273 			return (EADDRNOTAVAIL);
274 		/* FALLTHROUGH */
275 	case SIOCSIFADDR:
276 	case SIOCSIFNETMASK:
277 	case SIOCSIFDSTADDR:
278 		if (p && (error = suser(p)) != 0)
279 			return error;
280 
281 		if (ifp == 0)
282 			return (EADDRNOTAVAIL);
283 		if (ia == (struct in_ifaddr *)0) {
284 			ia = (struct in_ifaddr *)
285 				malloc(sizeof *ia, M_IFADDR, M_WAITOK | M_ZERO);
286 			if (ia == (struct in_ifaddr *)NULL)
287 				return (ENOBUFS);
288 			/*
289 			 * Protect from ipintr() traversing address list
290 			 * while we're modifying it.
291 			 */
292 			s = splnet();
293 
294 			TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
295 			ifa = &ia->ia_ifa;
296 			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
297 
298 			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
299 			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
300 			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
301 			ia->ia_sockmask.sin_len = 8;
302 			if (ifp->if_flags & IFF_BROADCAST) {
303 				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
304 				ia->ia_broadaddr.sin_family = AF_INET;
305 			}
306 			ia->ia_ifp = ifp;
307 			if (!(ifp->if_flags & IFF_LOOPBACK))
308 				in_interfaces++;
309 			splx(s);
310 		}
311 		break;
312 
313 	case SIOCSIFBRDADDR:
314 		if (p && (error = suser(p)) != 0)
315 			return error;
316 		/* FALLTHROUGH */
317 
318 	case SIOCGIFADDR:
319 	case SIOCGIFNETMASK:
320 	case SIOCGIFDSTADDR:
321 	case SIOCGIFBRDADDR:
322 		if (ia == (struct in_ifaddr *)0)
323 			return (EADDRNOTAVAIL);
324 		break;
325 	}
326 	switch (cmd) {
327 
328 	case SIOCGIFADDR:
329 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
330 		break;
331 
332 	case SIOCGIFBRDADDR:
333 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
334 			return (EINVAL);
335 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
336 		break;
337 
338 	case SIOCGIFDSTADDR:
339 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
340 			return (EINVAL);
341 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
342 		break;
343 
344 	case SIOCGIFNETMASK:
345 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
346 		break;
347 
348 	case SIOCSIFDSTADDR:
349 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
350 			return (EINVAL);
351 		oldaddr = ia->ia_dstaddr;
352 		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
353 		if (ifp->if_ioctl && (error = (*ifp->if_ioctl)
354 					(ifp, SIOCSIFDSTADDR, (caddr_t)ia))) {
355 			ia->ia_dstaddr = oldaddr;
356 			return (error);
357 		}
358 		if (ia->ia_flags & IFA_ROUTE) {
359 			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
360 			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
361 			ia->ia_ifa.ifa_dstaddr =
362 					(struct sockaddr *)&ia->ia_dstaddr;
363 			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
364 		}
365 		break;
366 
367 	case SIOCSIFBRDADDR:
368 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
369 			return (EINVAL);
370 		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
371 		break;
372 
373 	case SIOCSIFADDR:
374 		return (in_ifinit(ifp, ia,
375 		    (struct sockaddr_in *) &ifr->ifr_addr, 1));
376 
377 	case SIOCSIFNETMASK:
378 		i = ifra->ifra_addr.sin_addr.s_addr;
379 		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr = i);
380 		break;
381 
382 	case SIOCAIFADDR:
383 		maskIsNew = 0;
384 		hostIsNew = 1;
385 		error = 0;
386 		if (ia->ia_addr.sin_family == AF_INET) {
387 			if (ifra->ifra_addr.sin_len == 0) {
388 				ifra->ifra_addr = ia->ia_addr;
389 				hostIsNew = 0;
390 			} else if (ifra->ifra_addr.sin_addr.s_addr ==
391 					       ia->ia_addr.sin_addr.s_addr)
392 				hostIsNew = 0;
393 		}
394 		if (ifra->ifra_mask.sin_len) {
395 			in_ifscrub(ifp, ia);
396 			ia->ia_sockmask = ifra->ifra_mask;
397 			ia->ia_subnetmask =
398 			     ntohl(ia->ia_sockmask.sin_addr.s_addr);
399 			maskIsNew = 1;
400 		}
401 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
402 		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
403 			in_ifscrub(ifp, ia);
404 			ia->ia_dstaddr = ifra->ifra_dstaddr;
405 			maskIsNew  = 1; /* We lie; but the effect's the same */
406 		}
407 		if (ifra->ifra_addr.sin_family == AF_INET &&
408 		    (hostIsNew || maskIsNew))
409 			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
410 		if ((ifp->if_flags & IFF_BROADCAST) &&
411 		    (ifra->ifra_broadaddr.sin_family == AF_INET))
412 			ia->ia_broadaddr = ifra->ifra_broadaddr;
413 		return (error);
414 
415 	case SIOCDIFADDR:
416 		in_ifscrub(ifp, ia);
417 		/*
418 		 * Protect from ipintr() traversing address list
419 		 * while we're modifying it.
420 		 */
421 		s = splnet();
422 
423 		ifa = &ia->ia_ifa;
424 		TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
425 		oia = ia;
426 		TAILQ_REMOVE(&in_ifaddrhead, oia, ia_link);
427 		IFAFREE(&oia->ia_ifa);
428 		splx(s);
429 		break;
430 
431 	default:
432 		if (ifp == 0 || ifp->if_ioctl == 0)
433 			return (EOPNOTSUPP);
434 		return ((*ifp->if_ioctl)(ifp, cmd, data));
435 	}
436 	return (0);
437 }
438 
439 /*
440  * SIOC[GAD]LIFADDR.
441  *	SIOCGLIFADDR: get first address. (?!?)
442  *	SIOCGLIFADDR with IFLR_PREFIX:
443  *		get first address that matches the specified prefix.
444  *	SIOCALIFADDR: add the specified address.
445  *	SIOCALIFADDR with IFLR_PREFIX:
446  *		EINVAL since we can't deduce hostid part of the address.
447  *	SIOCDLIFADDR: delete the specified address.
448  *	SIOCDLIFADDR with IFLR_PREFIX:
449  *		delete the first address that matches the specified prefix.
450  * return values:
451  *	EINVAL on invalid parameters
452  *	EADDRNOTAVAIL on prefix match failed/specified address not found
453  *	other values may be returned from in_ioctl()
454  */
455 static int
456 in_lifaddr_ioctl(so, cmd, data, ifp, p)
457 	struct socket *so;
458 	u_long cmd;
459 	caddr_t	data;
460 	struct ifnet *ifp;
461 	struct proc *p;
462 {
463 	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
464 	struct ifaddr *ifa;
465 
466 	/* sanity checks */
467 	if (!data || !ifp) {
468 		panic("invalid argument to in_lifaddr_ioctl");
469 		/*NOTRECHED*/
470 	}
471 
472 	switch (cmd) {
473 	case SIOCGLIFADDR:
474 		/* address must be specified on GET with IFLR_PREFIX */
475 		if ((iflr->flags & IFLR_PREFIX) == 0)
476 			break;
477 		/*FALLTHROUGH*/
478 	case SIOCALIFADDR:
479 	case SIOCDLIFADDR:
480 		/* address must be specified on ADD and DELETE */
481 		if (iflr->addr.ss_family != AF_INET)
482 			return EINVAL;
483 		if (iflr->addr.ss_len != sizeof(struct sockaddr_in))
484 			return EINVAL;
485 		/* XXX need improvement */
486 		if (iflr->dstaddr.ss_family
487 		 && iflr->dstaddr.ss_family != AF_INET)
488 			return EINVAL;
489 		if (iflr->dstaddr.ss_family
490 		 && iflr->dstaddr.ss_len != sizeof(struct sockaddr_in))
491 			return EINVAL;
492 		break;
493 	default: /*shouldn't happen*/
494 		return EOPNOTSUPP;
495 	}
496 	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
497 		return EINVAL;
498 
499 	switch (cmd) {
500 	case SIOCALIFADDR:
501 	    {
502 		struct in_aliasreq ifra;
503 
504 		if (iflr->flags & IFLR_PREFIX)
505 			return EINVAL;
506 
507 		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
508 		bzero(&ifra, sizeof(ifra));
509 		bcopy(iflr->iflr_name, ifra.ifra_name,
510 			sizeof(ifra.ifra_name));
511 
512 		bcopy(&iflr->addr, &ifra.ifra_addr, iflr->addr.ss_len);
513 
514 		if (iflr->dstaddr.ss_family) {	/*XXX*/
515 			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
516 				iflr->dstaddr.ss_len);
517 		}
518 
519 		ifra.ifra_mask.sin_family = AF_INET;
520 		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
521 		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
522 
523 		return in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, p);
524 	    }
525 	case SIOCGLIFADDR:
526 	case SIOCDLIFADDR:
527 	    {
528 		struct in_ifaddr *ia;
529 		struct in_addr mask, candidate, match;
530 		struct sockaddr_in *sin;
531 		int cmp;
532 
533 		bzero(&mask, sizeof(mask));
534 		if (iflr->flags & IFLR_PREFIX) {
535 			/* lookup a prefix rather than address. */
536 			in_len2mask(&mask, iflr->prefixlen);
537 
538 			sin = (struct sockaddr_in *)&iflr->addr;
539 			match.s_addr = sin->sin_addr.s_addr;
540 			match.s_addr &= mask.s_addr;
541 
542 			/* if you set extra bits, that's wrong */
543 			if (match.s_addr != sin->sin_addr.s_addr)
544 				return EINVAL;
545 
546 			cmp = 1;
547 		} else {
548 			if (cmd == SIOCGLIFADDR) {
549 				/* on getting an address, take the 1st match */
550 				cmp = 0;	/*XXX*/
551 			} else {
552 				/* on deleting an address, do exact match */
553 				in_len2mask(&mask, 32);
554 				sin = (struct sockaddr_in *)&iflr->addr;
555 				match.s_addr = sin->sin_addr.s_addr;
556 
557 				cmp = 1;
558 			}
559 		}
560 
561 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)	{
562 			if (ifa->ifa_addr->sa_family != AF_INET6)
563 				continue;
564 			if (!cmp)
565 				break;
566 			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
567 			candidate.s_addr &= mask.s_addr;
568 			if (candidate.s_addr == match.s_addr)
569 				break;
570 		}
571 		if (!ifa)
572 			return EADDRNOTAVAIL;
573 		ia = (struct in_ifaddr *)ifa;
574 
575 		if (cmd == SIOCGLIFADDR) {
576 			/* fill in the if_laddrreq structure */
577 			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
578 
579 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
580 				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
581 					ia->ia_dstaddr.sin_len);
582 			} else
583 				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
584 
585 			iflr->prefixlen =
586 				in_mask2len(&ia->ia_sockmask.sin_addr);
587 
588 			iflr->flags = 0;	/*XXX*/
589 
590 			return 0;
591 		} else {
592 			struct in_aliasreq ifra;
593 
594 			/* fill in_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
595 			bzero(&ifra, sizeof(ifra));
596 			bcopy(iflr->iflr_name, ifra.ifra_name,
597 				sizeof(ifra.ifra_name));
598 
599 			bcopy(&ia->ia_addr, &ifra.ifra_addr,
600 				ia->ia_addr.sin_len);
601 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
602 				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
603 					ia->ia_dstaddr.sin_len);
604 			}
605 			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
606 				ia->ia_sockmask.sin_len);
607 
608 			return in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
609 					  ifp, p);
610 		}
611 	    }
612 	}
613 
614 	return EOPNOTSUPP;	/*just for safety*/
615 }
616 
617 /*
618  * Delete any existing route for an interface.
619  */
620 void
621 in_ifscrub(ifp, ia)
622 	register struct ifnet *ifp;
623 	register struct in_ifaddr *ia;
624 {
625 
626 	if ((ia->ia_flags & IFA_ROUTE) == 0)
627 		return;
628 	if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
629 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
630 	else
631 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
632 	ia->ia_flags &= ~IFA_ROUTE;
633 }
634 
635 /*
636  * Initialize an interface's internet address
637  * and routing table entry.
638  */
639 static int
640 in_ifinit(ifp, ia, sin, scrub)
641 	register struct ifnet *ifp;
642 	register struct in_ifaddr *ia;
643 	struct sockaddr_in *sin;
644 	int scrub;
645 {
646 	register u_long i = ntohl(sin->sin_addr.s_addr);
647 	struct sockaddr_in oldaddr;
648 	int s = splimp(), flags = RTF_UP, error;
649 
650 	oldaddr = ia->ia_addr;
651 	ia->ia_addr = *sin;
652 	/*
653 	 * Give the interface a chance to initialize
654 	 * if this is its first address,
655 	 * and to validate the address if necessary.
656 	 */
657 	if (ifp->if_ioctl &&
658 	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
659 		splx(s);
660 		ia->ia_addr = oldaddr;
661 		return (error);
662 	}
663 	splx(s);
664 	if (scrub) {
665 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
666 		in_ifscrub(ifp, ia);
667 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
668 	}
669 	if (IN_CLASSA(i))
670 		ia->ia_netmask = IN_CLASSA_NET;
671 	else if (IN_CLASSB(i))
672 		ia->ia_netmask = IN_CLASSB_NET;
673 	else
674 		ia->ia_netmask = IN_CLASSC_NET;
675 	/*
676 	 * The subnet mask usually includes at least the standard network part,
677 	 * but may may be smaller in the case of supernetting.
678 	 * If it is set, we believe it.
679 	 */
680 	if (ia->ia_subnetmask == 0) {
681 		ia->ia_subnetmask = ia->ia_netmask;
682 		ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
683 	} else
684 		ia->ia_netmask &= ia->ia_subnetmask;
685 	ia->ia_net = i & ia->ia_netmask;
686 	ia->ia_subnet = i & ia->ia_subnetmask;
687 	in_socktrim(&ia->ia_sockmask);
688 	/*
689 	 * Add route for the network.
690 	 */
691 	ia->ia_ifa.ifa_metric = ifp->if_metric;
692 	if (ifp->if_flags & IFF_BROADCAST) {
693 		ia->ia_broadaddr.sin_addr.s_addr =
694 			htonl(ia->ia_subnet | ~ia->ia_subnetmask);
695 		ia->ia_netbroadcast.s_addr =
696 			htonl(ia->ia_net | ~ ia->ia_netmask);
697 	} else if (ifp->if_flags & IFF_LOOPBACK) {
698 		ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
699 		flags |= RTF_HOST;
700 	} else if (ifp->if_flags & IFF_POINTOPOINT) {
701 		if (ia->ia_dstaddr.sin_family != AF_INET)
702 			return (0);
703 		flags |= RTF_HOST;
704 	}
705 	if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD, flags)) == 0)
706 		ia->ia_flags |= IFA_ROUTE;
707 
708 	/*
709 	 * If the interface supports multicast, join the "all hosts"
710 	 * multicast group on that interface.
711 	 */
712 	if (ifp->if_flags & IFF_MULTICAST) {
713 		struct in_addr addr;
714 
715 		addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
716 		in_addmulti(&addr, ifp);
717 	}
718 	return (error);
719 }
720 
721 
722 /*
723  * Return 1 if the address might be a local broadcast address.
724  */
725 int
726 in_broadcast(in, ifp)
727 	struct in_addr in;
728         struct ifnet *ifp;
729 {
730 	register struct ifaddr *ifa;
731 	u_long t;
732 
733 	if (in.s_addr == INADDR_BROADCAST ||
734 	    in.s_addr == INADDR_ANY)
735 		return 1;
736 	if ((ifp->if_flags & IFF_BROADCAST) == 0)
737 		return 0;
738 	t = ntohl(in.s_addr);
739 	/*
740 	 * Look through the list of addresses for a match
741 	 * with a broadcast address.
742 	 */
743 #define ia ((struct in_ifaddr *)ifa)
744 	for (ifa = TAILQ_FIRST(&ifp->if_addrhead); ifa;
745 	     ifa = TAILQ_NEXT(ifa, ifa_link))
746 		if (ifa->ifa_addr->sa_family == AF_INET &&
747 		    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
748 		     in.s_addr == ia->ia_netbroadcast.s_addr ||
749 		     /*
750 		      * Check for old-style (host 0) broadcast.
751 		      */
752 		     t == ia->ia_subnet || t == ia->ia_net) &&
753 		     /*
754 		      * Check for an all one subnetmask. These
755 		      * only exist when an interface gets a secondary
756 		      * address.
757 		      */
758 		     ia->ia_subnetmask != (u_long)0xffffffff)
759 			    return 1;
760 	return (0);
761 #undef ia
762 }
763 /*
764  * Add an address to the list of IP multicast addresses for a given interface.
765  */
766 struct in_multi *
767 in_addmulti(ap, ifp)
768 	register struct in_addr *ap;
769 	register struct ifnet *ifp;
770 {
771 	register struct in_multi *inm;
772 	int error;
773 	struct sockaddr_in sin;
774 	struct ifmultiaddr *ifma;
775 	int s = splnet();
776 
777 	/*
778 	 * Call generic routine to add membership or increment
779 	 * refcount.  It wants addresses in the form of a sockaddr,
780 	 * so we build one here (being careful to zero the unused bytes).
781 	 */
782 	bzero(&sin, sizeof sin);
783 	sin.sin_family = AF_INET;
784 	sin.sin_len = sizeof sin;
785 	sin.sin_addr = *ap;
786 	error = if_addmulti(ifp, (struct sockaddr *)&sin, &ifma);
787 	if (error) {
788 		splx(s);
789 		return 0;
790 	}
791 
792 	/*
793 	 * If ifma->ifma_protospec is null, then if_addmulti() created
794 	 * a new record.  Otherwise, we are done.
795 	 */
796 	if (ifma->ifma_protospec != 0) {
797 		splx(s);
798 		return ifma->ifma_protospec;
799 	}
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,
804 	    M_NOWAIT | M_ZERO);
805 	if (inm == NULL) {
806 		splx(s);
807 		return (NULL);
808 	}
809 
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