xref: /dragonfly/sys/netinet/in.c (revision 1d1731fa)
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: src/sys/netinet/in.c,v 1.44.2.14 2002/11/08 00:45:50 suz Exp $
35  * $DragonFly: src/sys/netinet/in.c,v 1.7 2003/08/23 11:18:00 rob Exp $
36  */
37 
38 #include "opt_bootp.h"
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/sockio.h>
42 #include <sys/malloc.h>
43 #include <sys/proc.h>
44 #include <sys/socket.h>
45 #include <sys/kernel.h>
46 #include <sys/sysctl.h>
47 
48 #include <net/if.h>
49 #include <net/if_types.h>
50 #include <net/route.h>
51 
52 #include <netinet/in.h>
53 #include <netinet/in_var.h>
54 #include <netinet/in_pcb.h>
55 
56 #include <netinet/igmp_var.h>
57 
58 static MALLOC_DEFINE(M_IPMADDR, "in_multi", "internet multicast address");
59 
60 static int in_mask2len (struct in_addr *);
61 static void in_len2mask (struct in_addr *, int);
62 static int in_lifaddr_ioctl (struct socket *, u_long, caddr_t,
63 	struct ifnet *, struct thread *);
64 
65 static void	in_socktrim (struct sockaddr_in *);
66 static int	in_ifinit (struct ifnet *,
67 	    struct in_ifaddr *, struct sockaddr_in *, int);
68 
69 static int subnetsarelocal = 0;
70 SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW,
71 	&subnetsarelocal, 0, "");
72 
73 struct in_multihead in_multihead; /* XXX BSS initialization */
74 
75 extern struct inpcbinfo ripcbinfo;
76 extern struct inpcbinfo udbinfo;
77 
78 /*
79  * Return 1 if an internet address is for a ``local'' host
80  * (one to which we have a connection).  If subnetsarelocal
81  * is true, this includes other subnets of the local net.
82  * Otherwise, it includes only the directly-connected (sub)nets.
83  */
84 int
85 in_localaddr(in)
86 	struct in_addr in;
87 {
88 	u_long i = ntohl(in.s_addr);
89 	struct in_ifaddr *ia;
90 
91 	if (subnetsarelocal) {
92 		TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link)
93 			if ((i & ia->ia_netmask) == ia->ia_net)
94 				return (1);
95 	} else {
96 		TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link)
97 			if ((i & ia->ia_subnetmask) == ia->ia_subnet)
98 				return (1);
99 	}
100 	return (0);
101 }
102 
103 /*
104  * Determine whether an IP address is in a reserved set of addresses
105  * that may not be forwarded, or whether datagrams to that destination
106  * may be forwarded.
107  */
108 int
109 in_canforward(in)
110 	struct in_addr in;
111 {
112 	u_long i = ntohl(in.s_addr);
113 	u_long net;
114 
115 	if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i))
116 		return (0);
117 	if (IN_CLASSA(i)) {
118 		net = i & IN_CLASSA_NET;
119 		if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
120 			return (0);
121 	}
122 	return (1);
123 }
124 
125 /*
126  * Trim a mask in a sockaddr
127  */
128 static void
129 in_socktrim(ap)
130 struct sockaddr_in *ap;
131 {
132     char *cplim = (char *) &ap->sin_addr;
133     char *cp = (char *) (&ap->sin_addr + 1);
134 
135     ap->sin_len = 0;
136     while (--cp >= cplim)
137         if (*cp) {
138 	    (ap)->sin_len = cp - (char *) (ap) + 1;
139 	    break;
140 	}
141 }
142 
143 static int
144 in_mask2len(mask)
145 	struct in_addr *mask;
146 {
147 	int x, y;
148 	u_char *p;
149 
150 	p = (u_char *)mask;
151 	for (x = 0; x < sizeof(*mask); x++) {
152 		if (p[x] != 0xff)
153 			break;
154 	}
155 	y = 0;
156 	if (x < sizeof(*mask)) {
157 		for (y = 0; y < 8; y++) {
158 			if ((p[x] & (0x80 >> y)) == 0)
159 				break;
160 		}
161 	}
162 	return x * 8 + y;
163 }
164 
165 static void
166 in_len2mask(mask, len)
167 	struct in_addr *mask;
168 	int len;
169 {
170 	int i;
171 	u_char *p;
172 
173 	p = (u_char *)mask;
174 	bzero(mask, sizeof(*mask));
175 	for (i = 0; i < len / 8; i++)
176 		p[i] = 0xff;
177 	if (len % 8)
178 		p[i] = (0xff00 >> (len % 8)) & 0xff;
179 }
180 
181 static int in_interfaces;	/* number of external internet interfaces */
182 
183 /*
184  * Generic internet control operations (ioctl's).
185  * Ifp is 0 if not an interface-specific ioctl.
186  *
187  * NOTE! td might be NULL.
188  */
189 /* ARGSUSED */
190 int
191 in_control(so, cmd, data, ifp, td)
192 	struct socket *so;
193 	u_long cmd;
194 	caddr_t data;
195 	struct ifnet *ifp;
196 	struct thread *td;
197 {
198 	struct ifreq *ifr = (struct ifreq *)data;
199 	struct in_ifaddr *ia = 0, *iap;
200 	struct ifaddr *ifa;
201 	struct in_addr dst;
202 	struct in_ifaddr *oia;
203 	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
204 	struct sockaddr_in oldaddr;
205 	int hostIsNew, iaIsNew, maskIsNew, s;
206 	int error = 0;
207 
208 	iaIsNew = 0;
209 
210 	switch (cmd) {
211 	case SIOCALIFADDR:
212 	case SIOCDLIFADDR:
213 		if (td && (error = suser(td)) != 0)
214 			return error;
215 		/*fall through*/
216 	case SIOCGLIFADDR:
217 		if (!ifp)
218 			return EINVAL;
219 		return in_lifaddr_ioctl(so, cmd, data, ifp, td);
220 	}
221 
222 	/*
223 	 * Find address for this interface, if it exists.
224 	 *
225 	 * If an alias address was specified, find that one instead of
226 	 * the first one on the interface, if possible
227 	 */
228 	if (ifp) {
229 		dst = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
230 		LIST_FOREACH(iap, INADDR_HASH(dst.s_addr), ia_hash)
231 			if (iap->ia_ifp == ifp &&
232 			    iap->ia_addr.sin_addr.s_addr == dst.s_addr) {
233 				ia = iap;
234 				break;
235 			}
236 		if (ia == NULL)
237 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
238 				iap = ifatoia(ifa);
239 				if (iap->ia_addr.sin_family == AF_INET) {
240 					ia = iap;
241 					break;
242 				}
243 			}
244 	}
245 
246 	switch (cmd) {
247 
248 	case SIOCAIFADDR:
249 	case SIOCDIFADDR:
250 		if (ifp == 0)
251 			return (EADDRNOTAVAIL);
252 		if (ifra->ifra_addr.sin_family == AF_INET) {
253 			for (oia = ia; ia; ia = TAILQ_NEXT(ia, ia_link)) {
254 				if (ia->ia_ifp == ifp  &&
255 				    ia->ia_addr.sin_addr.s_addr ==
256 				    ifra->ifra_addr.sin_addr.s_addr)
257 					break;
258 			}
259 			if ((ifp->if_flags & IFF_POINTOPOINT)
260 			    && (cmd == SIOCAIFADDR)
261 			    && (ifra->ifra_dstaddr.sin_addr.s_addr
262 				== INADDR_ANY)) {
263 				return EDESTADDRREQ;
264 			}
265 		}
266 		if (cmd == SIOCDIFADDR && ia == 0)
267 			return (EADDRNOTAVAIL);
268 		/* FALLTHROUGH */
269 	case SIOCSIFADDR:
270 	case SIOCSIFNETMASK:
271 	case SIOCSIFDSTADDR:
272 		if (td && (error = suser(td)) != 0)
273 			return error;
274 
275 		if (ifp == 0)
276 			return (EADDRNOTAVAIL);
277 		if (ia == (struct in_ifaddr *)0) {
278 			ia = (struct in_ifaddr *)
279 				malloc(sizeof *ia, M_IFADDR, M_WAITOK);
280 			if (ia == (struct in_ifaddr *)NULL)
281 				return (ENOBUFS);
282 			bzero((caddr_t)ia, sizeof *ia);
283 			/*
284 			 * Protect from ipintr() traversing address list
285 			 * while we're modifying it.
286 			 */
287 			s = splnet();
288 
289 			TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
290 			ifa = &ia->ia_ifa;
291 			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
292 
293 			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
294 			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
295 			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
296 			ia->ia_sockmask.sin_len = 8;
297 			ia->ia_sockmask.sin_family = AF_INET;
298 			if (ifp->if_flags & IFF_BROADCAST) {
299 				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
300 				ia->ia_broadaddr.sin_family = AF_INET;
301 			}
302 			ia->ia_ifp = ifp;
303 			if (!(ifp->if_flags & IFF_LOOPBACK))
304 				in_interfaces++;
305 			iaIsNew = 1;
306 			splx(s);
307 		}
308 		break;
309 
310 	case SIOCSIFBRDADDR:
311 		if (td && (error = suser(td)) != 0)
312 			return error;
313 		/* FALLTHROUGH */
314 
315 	case SIOCGIFADDR:
316 	case SIOCGIFNETMASK:
317 	case SIOCGIFDSTADDR:
318 	case SIOCGIFBRDADDR:
319 		if (ia == (struct in_ifaddr *)0)
320 			return (EADDRNOTAVAIL);
321 		break;
322 	}
323 	switch (cmd) {
324 
325 	case SIOCGIFADDR:
326 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
327 		return (0);
328 
329 	case SIOCGIFBRDADDR:
330 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
331 			return (EINVAL);
332 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
333 		return (0);
334 
335 	case SIOCGIFDSTADDR:
336 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
337 			return (EINVAL);
338 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
339 		return (0);
340 
341 	case SIOCGIFNETMASK:
342 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
343 		return (0);
344 
345 	case SIOCSIFDSTADDR:
346 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
347 			return (EINVAL);
348 		oldaddr = ia->ia_dstaddr;
349 		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
350 		if (ifp->if_ioctl && (error = (*ifp->if_ioctl)
351 					(ifp, SIOCSIFDSTADDR, (caddr_t)ia))) {
352 			ia->ia_dstaddr = oldaddr;
353 			return (error);
354 		}
355 		if (ia->ia_flags & IFA_ROUTE) {
356 			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
357 			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
358 			ia->ia_ifa.ifa_dstaddr =
359 					(struct sockaddr *)&ia->ia_dstaddr;
360 			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
361 		}
362 		return (0);
363 
364 	case SIOCSIFBRDADDR:
365 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
366 			return (EINVAL);
367 		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
368 		return (0);
369 
370 	case SIOCSIFADDR:
371 		error = in_ifinit(ifp, ia,
372 		    (struct sockaddr_in *) &ifr->ifr_addr, 1);
373 		if (error != 0 && iaIsNew)
374 			break;
375 		return (0);
376 
377 	case SIOCSIFNETMASK:
378 		ia->ia_sockmask.sin_addr = ifra->ifra_addr.sin_addr;
379 		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr);
380 		return (0);
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_sockmask.sin_family = AF_INET;
398 			ia->ia_subnetmask =
399 			     ntohl(ia->ia_sockmask.sin_addr.s_addr);
400 			maskIsNew = 1;
401 		}
402 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
403 		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
404 			in_ifscrub(ifp, ia);
405 			ia->ia_dstaddr = ifra->ifra_dstaddr;
406 			maskIsNew  = 1; /* We lie; but the effect's the same */
407 		}
408 		if (ifra->ifra_addr.sin_family == AF_INET &&
409 		    (hostIsNew || maskIsNew))
410 			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
411 
412 		if (error != 0 && iaIsNew)
413 			break;
414 
415 		if ((ifp->if_flags & IFF_BROADCAST) &&
416 		    (ifra->ifra_broadaddr.sin_family == AF_INET))
417 			ia->ia_broadaddr = ifra->ifra_broadaddr;
418 		return (error);
419 
420 	case SIOCDIFADDR:
421 		/*
422 		 * in_ifscrub kills the interface route.
423 		 */
424 		in_ifscrub(ifp, ia);
425 		/*
426 		 * in_ifadown gets rid of all the rest of
427 		 * the routes.  This is not quite the right
428 		 * thing to do, but at least if we are running
429 		 * a routing process they will come back.
430 		 */
431 		in_ifadown(&ia->ia_ifa, 1);
432 		/*
433 		 * XXX horrible hack to detect that we are being called
434 		 * from if_detach()
435 		 */
436 		if (!ifnet_addrs[ifp->if_index - 1]) {
437 			in_pcbpurgeif0(LIST_FIRST(ripcbinfo.listhead), ifp);
438 			in_pcbpurgeif0(LIST_FIRST(udbinfo.listhead), ifp);
439 		}
440 		error = 0;
441 		break;
442 
443 	default:
444 		if (ifp == 0 || ifp->if_ioctl == 0)
445 			return (EOPNOTSUPP);
446 		return ((*ifp->if_ioctl)(ifp, cmd, data));
447 	}
448 
449 	/*
450 	 * Protect from ipintr() traversing address list while we're modifying
451 	 * it.
452 	 */
453 	s = splnet();
454 	TAILQ_REMOVE(&ifp->if_addrhead, &ia->ia_ifa, ifa_link);
455 	TAILQ_REMOVE(&in_ifaddrhead, ia, ia_link);
456 	LIST_REMOVE(ia, ia_hash);
457 	IFAFREE(&ia->ia_ifa);
458 	splx(s);
459 
460 	return (error);
461 }
462 
463 /*
464  * SIOC[GAD]LIFADDR.
465  *	SIOCGLIFADDR: get first address. (?!?)
466  *	SIOCGLIFADDR with IFLR_PREFIX:
467  *		get first address that matches the specified prefix.
468  *	SIOCALIFADDR: add the specified address.
469  *	SIOCALIFADDR with IFLR_PREFIX:
470  *		EINVAL since we can't deduce hostid part of the address.
471  *	SIOCDLIFADDR: delete the specified address.
472  *	SIOCDLIFADDR with IFLR_PREFIX:
473  *		delete the first address that matches the specified prefix.
474  * return values:
475  *	EINVAL on invalid parameters
476  *	EADDRNOTAVAIL on prefix match failed/specified address not found
477  *	other values may be returned from in_ioctl()
478  *
479  * NOTE! td might be NULL.
480  */
481 static int
482 in_lifaddr_ioctl(so, cmd, data, ifp, td)
483 	struct socket *so;
484 	u_long cmd;
485 	caddr_t	data;
486 	struct ifnet *ifp;
487 	struct thread *td;
488 {
489 	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
490 	struct ifaddr *ifa;
491 
492 	/* sanity checks */
493 	if (!data || !ifp) {
494 		panic("invalid argument to in_lifaddr_ioctl");
495 		/*NOTRECHED*/
496 	}
497 
498 	switch (cmd) {
499 	case SIOCGLIFADDR:
500 		/* address must be specified on GET with IFLR_PREFIX */
501 		if ((iflr->flags & IFLR_PREFIX) == 0)
502 			break;
503 		/*FALLTHROUGH*/
504 	case SIOCALIFADDR:
505 	case SIOCDLIFADDR:
506 		/* address must be specified on ADD and DELETE */
507 		if (iflr->addr.ss_family != AF_INET)
508 			return EINVAL;
509 		if (iflr->addr.ss_len != sizeof(struct sockaddr_in))
510 			return EINVAL;
511 		/* XXX need improvement */
512 		if (iflr->dstaddr.ss_family
513 		 && iflr->dstaddr.ss_family != AF_INET)
514 			return EINVAL;
515 		if (iflr->dstaddr.ss_family
516 		 && iflr->dstaddr.ss_len != sizeof(struct sockaddr_in))
517 			return EINVAL;
518 		break;
519 	default: /*shouldn't happen*/
520 		return EOPNOTSUPP;
521 	}
522 	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
523 		return EINVAL;
524 
525 	switch (cmd) {
526 	case SIOCALIFADDR:
527 	    {
528 		struct in_aliasreq ifra;
529 
530 		if (iflr->flags & IFLR_PREFIX)
531 			return EINVAL;
532 
533 		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
534 		bzero(&ifra, sizeof(ifra));
535 		bcopy(iflr->iflr_name, ifra.ifra_name,
536 			sizeof(ifra.ifra_name));
537 
538 		bcopy(&iflr->addr, &ifra.ifra_addr, iflr->addr.ss_len);
539 
540 		if (iflr->dstaddr.ss_family) {	/*XXX*/
541 			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
542 				iflr->dstaddr.ss_len);
543 		}
544 
545 		ifra.ifra_mask.sin_family = AF_INET;
546 		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
547 		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
548 
549 		return in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, td);
550 	    }
551 	case SIOCGLIFADDR:
552 	case SIOCDLIFADDR:
553 	    {
554 		struct in_ifaddr *ia;
555 		struct in_addr mask, candidate, match;
556 		struct sockaddr_in *sin;
557 		int cmp;
558 
559 		bzero(&mask, sizeof(mask));
560 		if (iflr->flags & IFLR_PREFIX) {
561 			/* lookup a prefix rather than address. */
562 			in_len2mask(&mask, iflr->prefixlen);
563 
564 			sin = (struct sockaddr_in *)&iflr->addr;
565 			match.s_addr = sin->sin_addr.s_addr;
566 			match.s_addr &= mask.s_addr;
567 
568 			/* if you set extra bits, that's wrong */
569 			if (match.s_addr != sin->sin_addr.s_addr)
570 				return EINVAL;
571 
572 			cmp = 1;
573 		} else {
574 			if (cmd == SIOCGLIFADDR) {
575 				/* on getting an address, take the 1st match */
576 				cmp = 0;	/*XXX*/
577 			} else {
578 				/* on deleting an address, do exact match */
579 				in_len2mask(&mask, 32);
580 				sin = (struct sockaddr_in *)&iflr->addr;
581 				match.s_addr = sin->sin_addr.s_addr;
582 
583 				cmp = 1;
584 			}
585 		}
586 
587 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)	{
588 			if (ifa->ifa_addr->sa_family != AF_INET6)
589 				continue;
590 			if (!cmp)
591 				break;
592 			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
593 			candidate.s_addr &= mask.s_addr;
594 			if (candidate.s_addr == match.s_addr)
595 				break;
596 		}
597 		if (!ifa)
598 			return EADDRNOTAVAIL;
599 		ia = (struct in_ifaddr *)ifa;
600 
601 		if (cmd == SIOCGLIFADDR) {
602 			/* fill in the if_laddrreq structure */
603 			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
604 
605 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
606 				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
607 					ia->ia_dstaddr.sin_len);
608 			} else
609 				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
610 
611 			iflr->prefixlen =
612 				in_mask2len(&ia->ia_sockmask.sin_addr);
613 
614 			iflr->flags = 0;	/*XXX*/
615 
616 			return 0;
617 		} else {
618 			struct in_aliasreq ifra;
619 
620 			/* fill in_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
621 			bzero(&ifra, sizeof(ifra));
622 			bcopy(iflr->iflr_name, ifra.ifra_name,
623 				sizeof(ifra.ifra_name));
624 
625 			bcopy(&ia->ia_addr, &ifra.ifra_addr,
626 				ia->ia_addr.sin_len);
627 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
628 				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
629 					ia->ia_dstaddr.sin_len);
630 			}
631 			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
632 				ia->ia_sockmask.sin_len);
633 
634 			return in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
635 					  ifp, td);
636 		}
637 	    }
638 	}
639 
640 	return EOPNOTSUPP;	/*just for safety*/
641 }
642 
643 /*
644  * Delete any existing route for an interface.
645  */
646 void
647 in_ifscrub(ifp, ia)
648 	struct ifnet *ifp;
649 	struct in_ifaddr *ia;
650 {
651 
652 	if ((ia->ia_flags & IFA_ROUTE) == 0)
653 		return;
654 	if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
655 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
656 	else
657 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
658 	ia->ia_flags &= ~IFA_ROUTE;
659 }
660 
661 /*
662  * Initialize an interface's internet address
663  * and routing table entry.
664  */
665 static int
666 in_ifinit(ifp, ia, sin, scrub)
667 	struct ifnet *ifp;
668 	struct in_ifaddr *ia;
669 	struct sockaddr_in *sin;
670 	int scrub;
671 {
672 	u_long i = ntohl(sin->sin_addr.s_addr);
673 	struct sockaddr_in oldaddr;
674 	int s = splimp(), flags = RTF_UP, error = 0;
675 
676 	oldaddr = ia->ia_addr;
677 	if (oldaddr.sin_family == AF_INET)
678 		LIST_REMOVE(ia, ia_hash);
679 	ia->ia_addr = *sin;
680 	if (ia->ia_addr.sin_family == AF_INET)
681 		LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
682 		    ia, ia_hash);
683 	/*
684 	 * Give the interface a chance to initialize
685 	 * if this is its first address,
686 	 * and to validate the address if necessary.
687 	 */
688 	if (ifp->if_ioctl &&
689 	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
690 		splx(s);
691 		/* LIST_REMOVE(ia, ia_hash) is done in in_control */
692 		ia->ia_addr = oldaddr;
693 		if (ia->ia_addr.sin_family == AF_INET)
694 			LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
695 			    ia, ia_hash);
696 		return (error);
697 	}
698 	splx(s);
699 	if (scrub) {
700 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
701 		in_ifscrub(ifp, ia);
702 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
703 	}
704 	if (IN_CLASSA(i))
705 		ia->ia_netmask = IN_CLASSA_NET;
706 	else if (IN_CLASSB(i))
707 		ia->ia_netmask = IN_CLASSB_NET;
708 	else
709 		ia->ia_netmask = IN_CLASSC_NET;
710 	/*
711 	 * The subnet mask usually includes at least the standard network part,
712 	 * but may may be smaller in the case of supernetting.
713 	 * If it is set, we believe it.
714 	 */
715 	if (ia->ia_subnetmask == 0) {
716 		ia->ia_subnetmask = ia->ia_netmask;
717 		ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
718 	} else
719 		ia->ia_netmask &= ia->ia_subnetmask;
720 	ia->ia_net = i & ia->ia_netmask;
721 	ia->ia_subnet = i & ia->ia_subnetmask;
722 	in_socktrim(&ia->ia_sockmask);
723 	/*
724 	 * Add route for the network.
725 	 */
726 	ia->ia_ifa.ifa_metric = ifp->if_metric;
727 	if (ifp->if_flags & IFF_BROADCAST) {
728 		ia->ia_broadaddr.sin_addr.s_addr =
729 			htonl(ia->ia_subnet | ~ia->ia_subnetmask);
730 		ia->ia_netbroadcast.s_addr =
731 			htonl(ia->ia_net | ~ ia->ia_netmask);
732 	} else if (ifp->if_flags & IFF_LOOPBACK) {
733 		ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
734 		flags |= RTF_HOST;
735 	} else if (ifp->if_flags & IFF_POINTOPOINT) {
736 		if (ia->ia_dstaddr.sin_family != AF_INET)
737 			return (0);
738 		flags |= RTF_HOST;
739 	}
740 
741 	/*-
742 	 * Don't add host routes for interface addresses of
743 	 * 0.0.0.0 --> 0.255.255.255 netmask 255.0.0.0.  This makes it
744 	 * possible to assign several such address pairs with consistent
745 	 * results (no host route) and is required by BOOTP.
746 	 *
747 	 * XXX: This is ugly !  There should be a way for the caller to
748 	 *      say that they don't want a host route.
749 	 */
750 	if (ia->ia_addr.sin_addr.s_addr != INADDR_ANY ||
751 	    ia->ia_netmask != IN_CLASSA_NET ||
752 	    ia->ia_dstaddr.sin_addr.s_addr != htonl(IN_CLASSA_HOST)) {
753 		if ((error = rtinit(&ia->ia_ifa, (int)RTM_ADD, flags)) != 0) {
754 			ia->ia_addr = oldaddr;
755 			return (error);
756 		}
757 		ia->ia_flags |= IFA_ROUTE;
758 	}
759 
760 	/*
761 	 * If the interface supports multicast, join the "all hosts"
762 	 * multicast group on that interface.
763 	 */
764 	if (ifp->if_flags & IFF_MULTICAST) {
765 		struct in_addr addr;
766 
767 		addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
768 		in_addmulti(&addr, ifp);
769 	}
770 	return (error);
771 }
772 
773 
774 /*
775  * Return 1 if the address might be a local broadcast address.
776  */
777 int
778 in_broadcast(in, ifp)
779 	struct in_addr in;
780         struct ifnet *ifp;
781 {
782 	struct ifaddr *ifa;
783 	u_long t;
784 
785 	if (in.s_addr == INADDR_BROADCAST ||
786 	    in.s_addr == INADDR_ANY)
787 		return 1;
788 	if ((ifp->if_flags & IFF_BROADCAST) == 0)
789 		return 0;
790 	t = ntohl(in.s_addr);
791 	/*
792 	 * Look through the list of addresses for a match
793 	 * with a broadcast address.
794 	 */
795 #define ia ((struct in_ifaddr *)ifa)
796 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
797 		if (ifa->ifa_addr->sa_family == AF_INET &&
798 		    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
799 		     in.s_addr == ia->ia_netbroadcast.s_addr ||
800 		     /*
801 		      * Check for old-style (host 0) broadcast.
802 		      */
803 		     t == ia->ia_subnet || t == ia->ia_net) &&
804 		     /*
805 		      * Check for an all one subnetmask. These
806 		      * only exist when an interface gets a secondary
807 		      * address.
808 		      */
809 		     ia->ia_subnetmask != (u_long)0xffffffff)
810 			    return 1;
811 	return (0);
812 #undef ia
813 }
814 /*
815  * Add an address to the list of IP multicast addresses for a given interface.
816  */
817 struct in_multi *
818 in_addmulti(ap, ifp)
819 	struct in_addr *ap;
820 	struct ifnet *ifp;
821 {
822 	struct in_multi *inm;
823 	int error;
824 	struct sockaddr_in sin;
825 	struct ifmultiaddr *ifma;
826 	int s = splnet();
827 
828 	/*
829 	 * Call generic routine to add membership or increment
830 	 * refcount.  It wants addresses in the form of a sockaddr,
831 	 * so we build one here (being careful to zero the unused bytes).
832 	 */
833 	bzero(&sin, sizeof sin);
834 	sin.sin_family = AF_INET;
835 	sin.sin_len = sizeof sin;
836 	sin.sin_addr = *ap;
837 	error = if_addmulti(ifp, (struct sockaddr *)&sin, &ifma);
838 	if (error) {
839 		splx(s);
840 		return 0;
841 	}
842 
843 	/*
844 	 * If ifma->ifma_protospec is null, then if_addmulti() created
845 	 * a new record.  Otherwise, we are done.
846 	 */
847 	if (ifma->ifma_protospec != 0) {
848 		splx(s);
849 		return ifma->ifma_protospec;
850 	}
851 
852 	/* XXX - if_addmulti uses M_WAITOK.  Can this really be called
853 	   at interrupt time?  If so, need to fix if_addmulti. XXX */
854 	inm = (struct in_multi *)malloc(sizeof(*inm), M_IPMADDR, M_NOWAIT);
855 	if (inm == NULL) {
856 		splx(s);
857 		return (NULL);
858 	}
859 
860 	bzero(inm, sizeof *inm);
861 	inm->inm_addr = *ap;
862 	inm->inm_ifp = ifp;
863 	inm->inm_ifma = ifma;
864 	ifma->ifma_protospec = inm;
865 	LIST_INSERT_HEAD(&in_multihead, inm, inm_link);
866 
867 	/*
868 	 * Let IGMP know that we have joined a new IP multicast group.
869 	 */
870 	igmp_joingroup(inm);
871 	splx(s);
872 	return (inm);
873 }
874 
875 /*
876  * Delete a multicast address record.
877  */
878 void
879 in_delmulti(inm)
880 	struct in_multi *inm;
881 {
882 	struct ifmultiaddr *ifma = inm->inm_ifma;
883 	struct in_multi my_inm;
884 	int s = splnet();
885 
886 	my_inm.inm_ifp = NULL ; /* don't send the leave msg */
887 	if (ifma->ifma_refcount == 1) {
888 		/*
889 		 * No remaining claims to this record; let IGMP know that
890 		 * we are leaving the multicast group.
891 		 * But do it after the if_delmulti() which might reset
892 		 * the interface and nuke the packet.
893 		 */
894 		my_inm = *inm ;
895 		ifma->ifma_protospec = 0;
896 		LIST_REMOVE(inm, inm_link);
897 		free(inm, M_IPMADDR);
898 	}
899 	/* XXX - should be separate API for when we have an ifma? */
900 	if_delmulti(ifma->ifma_ifp, ifma->ifma_addr);
901 	if (my_inm.inm_ifp != NULL)
902 		igmp_leavegroup(&my_inm);
903 	splx(s);
904 }
905