xref: /dragonfly/sys/netinet/in.c (revision 984263bc)
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  */
36 
37 #include "opt_bootp.h"
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/sockio.h>
41 #include <sys/malloc.h>
42 #include <sys/proc.h>
43 #include <sys/socket.h>
44 #include <sys/kernel.h>
45 #include <sys/sysctl.h>
46 
47 #include <net/if.h>
48 #include <net/if_types.h>
49 #include <net/route.h>
50 
51 #include <netinet/in.h>
52 #include <netinet/in_var.h>
53 #include <netinet/in_pcb.h>
54 
55 #include <netinet/igmp_var.h>
56 
57 static MALLOC_DEFINE(M_IPMADDR, "in_multi", "internet multicast address");
58 
59 static int in_mask2len __P((struct in_addr *));
60 static void in_len2mask __P((struct in_addr *, int));
61 static int in_lifaddr_ioctl __P((struct socket *, u_long, caddr_t,
62 	struct ifnet *, struct proc *));
63 
64 static void	in_socktrim __P((struct sockaddr_in *));
65 static int	in_ifinit __P((struct ifnet *,
66 	    struct in_ifaddr *, struct sockaddr_in *, int));
67 
68 static int subnetsarelocal = 0;
69 SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW,
70 	&subnetsarelocal, 0, "");
71 
72 struct in_multihead in_multihead; /* XXX BSS initialization */
73 
74 extern struct inpcbinfo ripcbinfo;
75 extern struct inpcbinfo udbinfo;
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 		TAILQ_FOREACH(ia, &in_ifaddrhead, 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_addr dst;
199 	struct in_ifaddr *oia;
200 	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
201 	struct sockaddr_in oldaddr;
202 	int error, hostIsNew, iaIsNew, maskIsNew, s;
203 
204 	iaIsNew = 0;
205 
206 	switch (cmd) {
207 	case SIOCALIFADDR:
208 	case SIOCDLIFADDR:
209 		if (p && (error = suser(p)) != 0)
210 			return error;
211 		/*fall through*/
212 	case SIOCGLIFADDR:
213 		if (!ifp)
214 			return EINVAL;
215 		return in_lifaddr_ioctl(so, cmd, data, ifp, p);
216 	}
217 
218 	/*
219 	 * Find address for this interface, if it exists.
220 	 *
221 	 * If an alias address was specified, find that one instead of
222 	 * the first one on the interface, if possible
223 	 */
224 	if (ifp) {
225 		dst = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
226 		LIST_FOREACH(iap, INADDR_HASH(dst.s_addr), ia_hash)
227 			if (iap->ia_ifp == ifp &&
228 			    iap->ia_addr.sin_addr.s_addr == dst.s_addr) {
229 				ia = iap;
230 				break;
231 			}
232 		if (ia == NULL)
233 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
234 				iap = ifatoia(ifa);
235 				if (iap->ia_addr.sin_family == AF_INET) {
236 					ia = iap;
237 					break;
238 				}
239 			}
240 	}
241 
242 	switch (cmd) {
243 
244 	case SIOCAIFADDR:
245 	case SIOCDIFADDR:
246 		if (ifp == 0)
247 			return (EADDRNOTAVAIL);
248 		if (ifra->ifra_addr.sin_family == AF_INET) {
249 			for (oia = ia; ia; ia = TAILQ_NEXT(ia, ia_link)) {
250 				if (ia->ia_ifp == ifp  &&
251 				    ia->ia_addr.sin_addr.s_addr ==
252 				    ifra->ifra_addr.sin_addr.s_addr)
253 					break;
254 			}
255 			if ((ifp->if_flags & IFF_POINTOPOINT)
256 			    && (cmd == SIOCAIFADDR)
257 			    && (ifra->ifra_dstaddr.sin_addr.s_addr
258 				== INADDR_ANY)) {
259 				return EDESTADDRREQ;
260 			}
261 		}
262 		if (cmd == SIOCDIFADDR && ia == 0)
263 			return (EADDRNOTAVAIL);
264 		/* FALLTHROUGH */
265 	case SIOCSIFADDR:
266 	case SIOCSIFNETMASK:
267 	case SIOCSIFDSTADDR:
268 		if (p && (error = suser(p)) != 0)
269 			return error;
270 
271 		if (ifp == 0)
272 			return (EADDRNOTAVAIL);
273 		if (ia == (struct in_ifaddr *)0) {
274 			ia = (struct in_ifaddr *)
275 				malloc(sizeof *ia, M_IFADDR, M_WAITOK);
276 			if (ia == (struct in_ifaddr *)NULL)
277 				return (ENOBUFS);
278 			bzero((caddr_t)ia, sizeof *ia);
279 			/*
280 			 * Protect from ipintr() traversing address list
281 			 * while we're modifying it.
282 			 */
283 			s = splnet();
284 
285 			TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
286 			ifa = &ia->ia_ifa;
287 			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
288 
289 			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
290 			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
291 			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
292 			ia->ia_sockmask.sin_len = 8;
293 			ia->ia_sockmask.sin_family = AF_INET;
294 			if (ifp->if_flags & IFF_BROADCAST) {
295 				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
296 				ia->ia_broadaddr.sin_family = AF_INET;
297 			}
298 			ia->ia_ifp = ifp;
299 			if (!(ifp->if_flags & IFF_LOOPBACK))
300 				in_interfaces++;
301 			iaIsNew = 1;
302 			splx(s);
303 		}
304 		break;
305 
306 	case SIOCSIFBRDADDR:
307 		if (p && (error = suser(p)) != 0)
308 			return error;
309 		/* FALLTHROUGH */
310 
311 	case SIOCGIFADDR:
312 	case SIOCGIFNETMASK:
313 	case SIOCGIFDSTADDR:
314 	case SIOCGIFBRDADDR:
315 		if (ia == (struct in_ifaddr *)0)
316 			return (EADDRNOTAVAIL);
317 		break;
318 	}
319 	switch (cmd) {
320 
321 	case SIOCGIFADDR:
322 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
323 		return (0);
324 
325 	case SIOCGIFBRDADDR:
326 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
327 			return (EINVAL);
328 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
329 		return (0);
330 
331 	case SIOCGIFDSTADDR:
332 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
333 			return (EINVAL);
334 		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
335 		return (0);
336 
337 	case SIOCGIFNETMASK:
338 		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
339 		return (0);
340 
341 	case SIOCSIFDSTADDR:
342 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
343 			return (EINVAL);
344 		oldaddr = ia->ia_dstaddr;
345 		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
346 		if (ifp->if_ioctl && (error = (*ifp->if_ioctl)
347 					(ifp, SIOCSIFDSTADDR, (caddr_t)ia))) {
348 			ia->ia_dstaddr = oldaddr;
349 			return (error);
350 		}
351 		if (ia->ia_flags & IFA_ROUTE) {
352 			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
353 			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
354 			ia->ia_ifa.ifa_dstaddr =
355 					(struct sockaddr *)&ia->ia_dstaddr;
356 			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
357 		}
358 		return (0);
359 
360 	case SIOCSIFBRDADDR:
361 		if ((ifp->if_flags & IFF_BROADCAST) == 0)
362 			return (EINVAL);
363 		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
364 		return (0);
365 
366 	case SIOCSIFADDR:
367 		error = in_ifinit(ifp, ia,
368 		    (struct sockaddr_in *) &ifr->ifr_addr, 1);
369 		if (error != 0 && iaIsNew)
370 			break;
371 		return (0);
372 
373 	case SIOCSIFNETMASK:
374 		ia->ia_sockmask.sin_addr = ifra->ifra_addr.sin_addr;
375 		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr);
376 		return (0);
377 
378 	case SIOCAIFADDR:
379 		maskIsNew = 0;
380 		hostIsNew = 1;
381 		error = 0;
382 		if (ia->ia_addr.sin_family == AF_INET) {
383 			if (ifra->ifra_addr.sin_len == 0) {
384 				ifra->ifra_addr = ia->ia_addr;
385 				hostIsNew = 0;
386 			} else if (ifra->ifra_addr.sin_addr.s_addr ==
387 					       ia->ia_addr.sin_addr.s_addr)
388 				hostIsNew = 0;
389 		}
390 		if (ifra->ifra_mask.sin_len) {
391 			in_ifscrub(ifp, ia);
392 			ia->ia_sockmask = ifra->ifra_mask;
393 			ia->ia_sockmask.sin_family = AF_INET;
394 			ia->ia_subnetmask =
395 			     ntohl(ia->ia_sockmask.sin_addr.s_addr);
396 			maskIsNew = 1;
397 		}
398 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
399 		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
400 			in_ifscrub(ifp, ia);
401 			ia->ia_dstaddr = ifra->ifra_dstaddr;
402 			maskIsNew  = 1; /* We lie; but the effect's the same */
403 		}
404 		if (ifra->ifra_addr.sin_family == AF_INET &&
405 		    (hostIsNew || maskIsNew))
406 			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
407 
408 		if (error != 0 && iaIsNew)
409 			break;
410 
411 		if ((ifp->if_flags & IFF_BROADCAST) &&
412 		    (ifra->ifra_broadaddr.sin_family == AF_INET))
413 			ia->ia_broadaddr = ifra->ifra_broadaddr;
414 		return (error);
415 
416 	case SIOCDIFADDR:
417 		/*
418 		 * in_ifscrub kills the interface route.
419 		 */
420 		in_ifscrub(ifp, ia);
421 		/*
422 		 * in_ifadown gets rid of all the rest of
423 		 * the routes.  This is not quite the right
424 		 * thing to do, but at least if we are running
425 		 * a routing process they will come back.
426 		 */
427 		in_ifadown(&ia->ia_ifa, 1);
428 		/*
429 		 * XXX horrible hack to detect that we are being called
430 		 * from if_detach()
431 		 */
432 		if (!ifnet_addrs[ifp->if_index - 1]) {
433 			in_pcbpurgeif0(LIST_FIRST(ripcbinfo.listhead), ifp);
434 			in_pcbpurgeif0(LIST_FIRST(udbinfo.listhead), ifp);
435 		}
436 		error = 0;
437 		break;
438 
439 	default:
440 		if (ifp == 0 || ifp->if_ioctl == 0)
441 			return (EOPNOTSUPP);
442 		return ((*ifp->if_ioctl)(ifp, cmd, data));
443 	}
444 
445 	/*
446 	 * Protect from ipintr() traversing address list while we're modifying
447 	 * it.
448 	 */
449 	s = splnet();
450 	TAILQ_REMOVE(&ifp->if_addrhead, &ia->ia_ifa, ifa_link);
451 	TAILQ_REMOVE(&in_ifaddrhead, ia, ia_link);
452 	LIST_REMOVE(ia, ia_hash);
453 	IFAFREE(&ia->ia_ifa);
454 	splx(s);
455 
456 	return (error);
457 }
458 
459 /*
460  * SIOC[GAD]LIFADDR.
461  *	SIOCGLIFADDR: get first address. (?!?)
462  *	SIOCGLIFADDR with IFLR_PREFIX:
463  *		get first address that matches the specified prefix.
464  *	SIOCALIFADDR: add the specified address.
465  *	SIOCALIFADDR with IFLR_PREFIX:
466  *		EINVAL since we can't deduce hostid part of the address.
467  *	SIOCDLIFADDR: delete the specified address.
468  *	SIOCDLIFADDR with IFLR_PREFIX:
469  *		delete the first address that matches the specified prefix.
470  * return values:
471  *	EINVAL on invalid parameters
472  *	EADDRNOTAVAIL on prefix match failed/specified address not found
473  *	other values may be returned from in_ioctl()
474  */
475 static int
476 in_lifaddr_ioctl(so, cmd, data, ifp, p)
477 	struct socket *so;
478 	u_long cmd;
479 	caddr_t	data;
480 	struct ifnet *ifp;
481 	struct proc *p;
482 {
483 	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
484 	struct ifaddr *ifa;
485 
486 	/* sanity checks */
487 	if (!data || !ifp) {
488 		panic("invalid argument to in_lifaddr_ioctl");
489 		/*NOTRECHED*/
490 	}
491 
492 	switch (cmd) {
493 	case SIOCGLIFADDR:
494 		/* address must be specified on GET with IFLR_PREFIX */
495 		if ((iflr->flags & IFLR_PREFIX) == 0)
496 			break;
497 		/*FALLTHROUGH*/
498 	case SIOCALIFADDR:
499 	case SIOCDLIFADDR:
500 		/* address must be specified on ADD and DELETE */
501 		if (iflr->addr.ss_family != AF_INET)
502 			return EINVAL;
503 		if (iflr->addr.ss_len != sizeof(struct sockaddr_in))
504 			return EINVAL;
505 		/* XXX need improvement */
506 		if (iflr->dstaddr.ss_family
507 		 && iflr->dstaddr.ss_family != AF_INET)
508 			return EINVAL;
509 		if (iflr->dstaddr.ss_family
510 		 && iflr->dstaddr.ss_len != sizeof(struct sockaddr_in))
511 			return EINVAL;
512 		break;
513 	default: /*shouldn't happen*/
514 		return EOPNOTSUPP;
515 	}
516 	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
517 		return EINVAL;
518 
519 	switch (cmd) {
520 	case SIOCALIFADDR:
521 	    {
522 		struct in_aliasreq ifra;
523 
524 		if (iflr->flags & IFLR_PREFIX)
525 			return EINVAL;
526 
527 		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
528 		bzero(&ifra, sizeof(ifra));
529 		bcopy(iflr->iflr_name, ifra.ifra_name,
530 			sizeof(ifra.ifra_name));
531 
532 		bcopy(&iflr->addr, &ifra.ifra_addr, iflr->addr.ss_len);
533 
534 		if (iflr->dstaddr.ss_family) {	/*XXX*/
535 			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
536 				iflr->dstaddr.ss_len);
537 		}
538 
539 		ifra.ifra_mask.sin_family = AF_INET;
540 		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
541 		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
542 
543 		return in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, p);
544 	    }
545 	case SIOCGLIFADDR:
546 	case SIOCDLIFADDR:
547 	    {
548 		struct in_ifaddr *ia;
549 		struct in_addr mask, candidate, match;
550 		struct sockaddr_in *sin;
551 		int cmp;
552 
553 		bzero(&mask, sizeof(mask));
554 		if (iflr->flags & IFLR_PREFIX) {
555 			/* lookup a prefix rather than address. */
556 			in_len2mask(&mask, iflr->prefixlen);
557 
558 			sin = (struct sockaddr_in *)&iflr->addr;
559 			match.s_addr = sin->sin_addr.s_addr;
560 			match.s_addr &= mask.s_addr;
561 
562 			/* if you set extra bits, that's wrong */
563 			if (match.s_addr != sin->sin_addr.s_addr)
564 				return EINVAL;
565 
566 			cmp = 1;
567 		} else {
568 			if (cmd == SIOCGLIFADDR) {
569 				/* on getting an address, take the 1st match */
570 				cmp = 0;	/*XXX*/
571 			} else {
572 				/* on deleting an address, do exact match */
573 				in_len2mask(&mask, 32);
574 				sin = (struct sockaddr_in *)&iflr->addr;
575 				match.s_addr = sin->sin_addr.s_addr;
576 
577 				cmp = 1;
578 			}
579 		}
580 
581 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)	{
582 			if (ifa->ifa_addr->sa_family != AF_INET6)
583 				continue;
584 			if (!cmp)
585 				break;
586 			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
587 			candidate.s_addr &= mask.s_addr;
588 			if (candidate.s_addr == match.s_addr)
589 				break;
590 		}
591 		if (!ifa)
592 			return EADDRNOTAVAIL;
593 		ia = (struct in_ifaddr *)ifa;
594 
595 		if (cmd == SIOCGLIFADDR) {
596 			/* fill in the if_laddrreq structure */
597 			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
598 
599 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
600 				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
601 					ia->ia_dstaddr.sin_len);
602 			} else
603 				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
604 
605 			iflr->prefixlen =
606 				in_mask2len(&ia->ia_sockmask.sin_addr);
607 
608 			iflr->flags = 0;	/*XXX*/
609 
610 			return 0;
611 		} else {
612 			struct in_aliasreq ifra;
613 
614 			/* fill in_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
615 			bzero(&ifra, sizeof(ifra));
616 			bcopy(iflr->iflr_name, ifra.ifra_name,
617 				sizeof(ifra.ifra_name));
618 
619 			bcopy(&ia->ia_addr, &ifra.ifra_addr,
620 				ia->ia_addr.sin_len);
621 			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
622 				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
623 					ia->ia_dstaddr.sin_len);
624 			}
625 			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
626 				ia->ia_sockmask.sin_len);
627 
628 			return in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
629 					  ifp, p);
630 		}
631 	    }
632 	}
633 
634 	return EOPNOTSUPP;	/*just for safety*/
635 }
636 
637 /*
638  * Delete any existing route for an interface.
639  */
640 void
641 in_ifscrub(ifp, ia)
642 	register struct ifnet *ifp;
643 	register struct in_ifaddr *ia;
644 {
645 
646 	if ((ia->ia_flags & IFA_ROUTE) == 0)
647 		return;
648 	if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
649 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
650 	else
651 		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
652 	ia->ia_flags &= ~IFA_ROUTE;
653 }
654 
655 /*
656  * Initialize an interface's internet address
657  * and routing table entry.
658  */
659 static int
660 in_ifinit(ifp, ia, sin, scrub)
661 	register struct ifnet *ifp;
662 	register struct in_ifaddr *ia;
663 	struct sockaddr_in *sin;
664 	int scrub;
665 {
666 	register u_long i = ntohl(sin->sin_addr.s_addr);
667 	struct sockaddr_in oldaddr;
668 	int s = splimp(), flags = RTF_UP, error = 0;
669 
670 	oldaddr = ia->ia_addr;
671 	if (oldaddr.sin_family == AF_INET)
672 		LIST_REMOVE(ia, ia_hash);
673 	ia->ia_addr = *sin;
674 	if (ia->ia_addr.sin_family == AF_INET)
675 		LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
676 		    ia, ia_hash);
677 	/*
678 	 * Give the interface a chance to initialize
679 	 * if this is its first address,
680 	 * and to validate the address if necessary.
681 	 */
682 	if (ifp->if_ioctl &&
683 	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
684 		splx(s);
685 		/* LIST_REMOVE(ia, ia_hash) is done in in_control */
686 		ia->ia_addr = oldaddr;
687 		if (ia->ia_addr.sin_family == AF_INET)
688 			LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
689 			    ia, ia_hash);
690 		return (error);
691 	}
692 	splx(s);
693 	if (scrub) {
694 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
695 		in_ifscrub(ifp, ia);
696 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
697 	}
698 	if (IN_CLASSA(i))
699 		ia->ia_netmask = IN_CLASSA_NET;
700 	else if (IN_CLASSB(i))
701 		ia->ia_netmask = IN_CLASSB_NET;
702 	else
703 		ia->ia_netmask = IN_CLASSC_NET;
704 	/*
705 	 * The subnet mask usually includes at least the standard network part,
706 	 * but may may be smaller in the case of supernetting.
707 	 * If it is set, we believe it.
708 	 */
709 	if (ia->ia_subnetmask == 0) {
710 		ia->ia_subnetmask = ia->ia_netmask;
711 		ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
712 	} else
713 		ia->ia_netmask &= ia->ia_subnetmask;
714 	ia->ia_net = i & ia->ia_netmask;
715 	ia->ia_subnet = i & ia->ia_subnetmask;
716 	in_socktrim(&ia->ia_sockmask);
717 	/*
718 	 * Add route for the network.
719 	 */
720 	ia->ia_ifa.ifa_metric = ifp->if_metric;
721 	if (ifp->if_flags & IFF_BROADCAST) {
722 		ia->ia_broadaddr.sin_addr.s_addr =
723 			htonl(ia->ia_subnet | ~ia->ia_subnetmask);
724 		ia->ia_netbroadcast.s_addr =
725 			htonl(ia->ia_net | ~ ia->ia_netmask);
726 	} else if (ifp->if_flags & IFF_LOOPBACK) {
727 		ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
728 		flags |= RTF_HOST;
729 	} else if (ifp->if_flags & IFF_POINTOPOINT) {
730 		if (ia->ia_dstaddr.sin_family != AF_INET)
731 			return (0);
732 		flags |= RTF_HOST;
733 	}
734 
735 	/*-
736 	 * Don't add host routes for interface addresses of
737 	 * 0.0.0.0 --> 0.255.255.255 netmask 255.0.0.0.  This makes it
738 	 * possible to assign several such address pairs with consistent
739 	 * results (no host route) and is required by BOOTP.
740 	 *
741 	 * XXX: This is ugly !  There should be a way for the caller to
742 	 *      say that they don't want a host route.
743 	 */
744 	if (ia->ia_addr.sin_addr.s_addr != INADDR_ANY ||
745 	    ia->ia_netmask != IN_CLASSA_NET ||
746 	    ia->ia_dstaddr.sin_addr.s_addr != htonl(IN_CLASSA_HOST)) {
747 		if ((error = rtinit(&ia->ia_ifa, (int)RTM_ADD, flags)) != 0) {
748 			ia->ia_addr = oldaddr;
749 			return (error);
750 		}
751 		ia->ia_flags |= IFA_ROUTE;
752 	}
753 
754 	/*
755 	 * If the interface supports multicast, join the "all hosts"
756 	 * multicast group on that interface.
757 	 */
758 	if (ifp->if_flags & IFF_MULTICAST) {
759 		struct in_addr addr;
760 
761 		addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
762 		in_addmulti(&addr, ifp);
763 	}
764 	return (error);
765 }
766 
767 
768 /*
769  * Return 1 if the address might be a local broadcast address.
770  */
771 int
772 in_broadcast(in, ifp)
773 	struct in_addr in;
774         struct ifnet *ifp;
775 {
776 	register struct ifaddr *ifa;
777 	u_long t;
778 
779 	if (in.s_addr == INADDR_BROADCAST ||
780 	    in.s_addr == INADDR_ANY)
781 		return 1;
782 	if ((ifp->if_flags & IFF_BROADCAST) == 0)
783 		return 0;
784 	t = ntohl(in.s_addr);
785 	/*
786 	 * Look through the list of addresses for a match
787 	 * with a broadcast address.
788 	 */
789 #define ia ((struct in_ifaddr *)ifa)
790 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
791 		if (ifa->ifa_addr->sa_family == AF_INET &&
792 		    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
793 		     in.s_addr == ia->ia_netbroadcast.s_addr ||
794 		     /*
795 		      * Check for old-style (host 0) broadcast.
796 		      */
797 		     t == ia->ia_subnet || t == ia->ia_net) &&
798 		     /*
799 		      * Check for an all one subnetmask. These
800 		      * only exist when an interface gets a secondary
801 		      * address.
802 		      */
803 		     ia->ia_subnetmask != (u_long)0xffffffff)
804 			    return 1;
805 	return (0);
806 #undef ia
807 }
808 /*
809  * Add an address to the list of IP multicast addresses for a given interface.
810  */
811 struct in_multi *
812 in_addmulti(ap, ifp)
813 	register struct in_addr *ap;
814 	register struct ifnet *ifp;
815 {
816 	register struct in_multi *inm;
817 	int error;
818 	struct sockaddr_in sin;
819 	struct ifmultiaddr *ifma;
820 	int s = splnet();
821 
822 	/*
823 	 * Call generic routine to add membership or increment
824 	 * refcount.  It wants addresses in the form of a sockaddr,
825 	 * so we build one here (being careful to zero the unused bytes).
826 	 */
827 	bzero(&sin, sizeof sin);
828 	sin.sin_family = AF_INET;
829 	sin.sin_len = sizeof sin;
830 	sin.sin_addr = *ap;
831 	error = if_addmulti(ifp, (struct sockaddr *)&sin, &ifma);
832 	if (error) {
833 		splx(s);
834 		return 0;
835 	}
836 
837 	/*
838 	 * If ifma->ifma_protospec is null, then if_addmulti() created
839 	 * a new record.  Otherwise, we are done.
840 	 */
841 	if (ifma->ifma_protospec != 0) {
842 		splx(s);
843 		return ifma->ifma_protospec;
844 	}
845 
846 	/* XXX - if_addmulti uses M_WAITOK.  Can this really be called
847 	   at interrupt time?  If so, need to fix if_addmulti. XXX */
848 	inm = (struct in_multi *)malloc(sizeof(*inm), M_IPMADDR, M_NOWAIT);
849 	if (inm == NULL) {
850 		splx(s);
851 		return (NULL);
852 	}
853 
854 	bzero(inm, sizeof *inm);
855 	inm->inm_addr = *ap;
856 	inm->inm_ifp = ifp;
857 	inm->inm_ifma = ifma;
858 	ifma->ifma_protospec = inm;
859 	LIST_INSERT_HEAD(&in_multihead, inm, inm_link);
860 
861 	/*
862 	 * Let IGMP know that we have joined a new IP multicast group.
863 	 */
864 	igmp_joingroup(inm);
865 	splx(s);
866 	return (inm);
867 }
868 
869 /*
870  * Delete a multicast address record.
871  */
872 void
873 in_delmulti(inm)
874 	register struct in_multi *inm;
875 {
876 	struct ifmultiaddr *ifma = inm->inm_ifma;
877 	struct in_multi my_inm;
878 	int s = splnet();
879 
880 	my_inm.inm_ifp = NULL ; /* don't send the leave msg */
881 	if (ifma->ifma_refcount == 1) {
882 		/*
883 		 * No remaining claims to this record; let IGMP know that
884 		 * we are leaving the multicast group.
885 		 * But do it after the if_delmulti() which might reset
886 		 * the interface and nuke the packet.
887 		 */
888 		my_inm = *inm ;
889 		ifma->ifma_protospec = 0;
890 		LIST_REMOVE(inm, inm_link);
891 		free(inm, M_IPMADDR);
892 	}
893 	/* XXX - should be separate API for when we have an ifma? */
894 	if_delmulti(ifma->ifma_ifp, ifma->ifma_addr);
895 	if (my_inm.inm_ifp != NULL)
896 		igmp_leavegroup(&my_inm);
897 	splx(s);
898 }
899