in.c revision 64853
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: head/sys/netinet/in.c 64853 2000-08-19 22:10:10Z bde $
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
60static MALLOC_DEFINE(M_IPMADDR, "in_multi", "internet multicast address");
61
62static int in_mask2len __P((struct in_addr *));
63static void in_len2mask __P((struct in_addr *, int));
64static int in_lifaddr_ioctl __P((struct socket *, u_long, caddr_t,
65	struct ifnet *, struct proc *));
66
67static void	in_socktrim __P((struct sockaddr_in *));
68static int	in_ifinit __P((struct ifnet *,
69	    struct in_ifaddr *, struct sockaddr_in *, int));
70
71static int subnetsarelocal = 0;
72SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW,
73	&subnetsarelocal, 0, "");
74
75struct 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 */
83int
84in_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 */
109int
110in_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 */
129static void
130in_socktrim(ap)
131struct 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
144static int
145in_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
166static void
167in_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
182static 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 */
189int
190in_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		case SIOCDIFPHYADDR:
211			if (p &&
212			    (error = suser(p)) != 0)
213        			return(error);
214                case SIOCGIFPSRCADDR:
215                case SIOCGIFPDSTADDR:
216                        return gif_ioctl(ifp, cmd, data);
217                }
218        }
219#endif
220
221	switch (cmd) {
222	case SIOCALIFADDR:
223	case SIOCDLIFADDR:
224		if (p && (error = suser(p)) != 0)
225			return error;
226		/*fall through*/
227	case SIOCGLIFADDR:
228		if (!ifp)
229			return EINVAL;
230		return in_lifaddr_ioctl(so, cmd, data, ifp, p);
231	}
232
233	/*
234	 * Find address for this interface, if it exists.
235	 *
236	 * If an alias address was specified, find that one instead of
237	 * the first one on the interface.
238	 */
239	if (ifp)
240		for (iap = in_ifaddrhead.tqh_first; iap;
241		     iap = iap->ia_link.tqe_next)
242			if (iap->ia_ifp == ifp) {
243				if (((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr.s_addr ==
244				    iap->ia_addr.sin_addr.s_addr) {
245					ia = iap;
246					break;
247				} else if (ia == NULL) {
248					ia = iap;
249					if (ifr->ifr_addr.sa_family != AF_INET)
250						break;
251				}
252			}
253
254	switch (cmd) {
255
256	case SIOCAIFADDR:
257	case SIOCDIFADDR:
258		if (ifp == 0)
259			return (EADDRNOTAVAIL);
260		if (ifra->ifra_addr.sin_family == AF_INET) {
261			for (oia = ia; ia; ia = ia->ia_link.tqe_next) {
262				if (ia->ia_ifp == ifp  &&
263				    ia->ia_addr.sin_addr.s_addr ==
264				    ifra->ifra_addr.sin_addr.s_addr)
265					break;
266			}
267			if ((ifp->if_flags & IFF_POINTOPOINT)
268			    && (cmd == SIOCAIFADDR)
269			    && (ifra->ifra_dstaddr.sin_addr.s_addr
270				== INADDR_ANY)) {
271				return EDESTADDRREQ;
272			}
273		}
274		if (cmd == SIOCDIFADDR && ia == 0)
275			return (EADDRNOTAVAIL);
276		/* FALLTHROUGH */
277	case SIOCSIFADDR:
278	case SIOCSIFNETMASK:
279	case SIOCSIFDSTADDR:
280		if (p && (error = suser(p)) != 0)
281			return error;
282
283		if (ifp == 0)
284			return (EADDRNOTAVAIL);
285		if (ia == (struct in_ifaddr *)0) {
286			ia = (struct in_ifaddr *)
287				malloc(sizeof *ia, M_IFADDR, M_WAITOK);
288			if (ia == (struct in_ifaddr *)NULL)
289				return (ENOBUFS);
290			bzero((caddr_t)ia, sizeof *ia);
291			/*
292			 * Protect from ipintr() traversing address list
293			 * while we're modifying it.
294			 */
295			s = splnet();
296
297			TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
298			ifa = &ia->ia_ifa;
299			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
300
301			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
302			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
303			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
304			ia->ia_sockmask.sin_len = 8;
305			if (ifp->if_flags & IFF_BROADCAST) {
306				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
307				ia->ia_broadaddr.sin_family = AF_INET;
308			}
309			ia->ia_ifp = ifp;
310			if (!(ifp->if_flags & IFF_LOOPBACK))
311				in_interfaces++;
312			splx(s);
313		}
314		break;
315
316	case SIOCSIFBRDADDR:
317		if (p && (error = suser(p)) != 0)
318			return error;
319		/* FALLTHROUGH */
320
321	case SIOCGIFADDR:
322	case SIOCGIFNETMASK:
323	case SIOCGIFDSTADDR:
324	case SIOCGIFBRDADDR:
325		if (ia == (struct in_ifaddr *)0)
326			return (EADDRNOTAVAIL);
327		break;
328	}
329	switch (cmd) {
330
331	case SIOCGIFADDR:
332		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
333		break;
334
335	case SIOCGIFBRDADDR:
336		if ((ifp->if_flags & IFF_BROADCAST) == 0)
337			return (EINVAL);
338		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
339		break;
340
341	case SIOCGIFDSTADDR:
342		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
343			return (EINVAL);
344		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
345		break;
346
347	case SIOCGIFNETMASK:
348		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
349		break;
350
351	case SIOCSIFDSTADDR:
352		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
353			return (EINVAL);
354		oldaddr = ia->ia_dstaddr;
355		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
356		if (ifp->if_ioctl && (error = (*ifp->if_ioctl)
357					(ifp, SIOCSIFDSTADDR, (caddr_t)ia))) {
358			ia->ia_dstaddr = oldaddr;
359			return (error);
360		}
361		if (ia->ia_flags & IFA_ROUTE) {
362			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
363			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
364			ia->ia_ifa.ifa_dstaddr =
365					(struct sockaddr *)&ia->ia_dstaddr;
366			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
367		}
368		break;
369
370	case SIOCSIFBRDADDR:
371		if ((ifp->if_flags & IFF_BROADCAST) == 0)
372			return (EINVAL);
373		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
374		break;
375
376	case SIOCSIFADDR:
377		return (in_ifinit(ifp, ia,
378		    (struct sockaddr_in *) &ifr->ifr_addr, 1));
379
380	case SIOCSIFNETMASK:
381		i = ifra->ifra_addr.sin_addr.s_addr;
382		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr = i);
383		break;
384
385	case SIOCAIFADDR:
386		maskIsNew = 0;
387		hostIsNew = 1;
388		error = 0;
389		if (ia->ia_addr.sin_family == AF_INET) {
390			if (ifra->ifra_addr.sin_len == 0) {
391				ifra->ifra_addr = ia->ia_addr;
392				hostIsNew = 0;
393			} else if (ifra->ifra_addr.sin_addr.s_addr ==
394					       ia->ia_addr.sin_addr.s_addr)
395				hostIsNew = 0;
396		}
397		if (ifra->ifra_mask.sin_len) {
398			in_ifscrub(ifp, ia);
399			ia->ia_sockmask = ifra->ifra_mask;
400			ia->ia_subnetmask =
401			     ntohl(ia->ia_sockmask.sin_addr.s_addr);
402			maskIsNew = 1;
403		}
404		if ((ifp->if_flags & IFF_POINTOPOINT) &&
405		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
406			in_ifscrub(ifp, ia);
407			ia->ia_dstaddr = ifra->ifra_dstaddr;
408			maskIsNew  = 1; /* We lie; but the effect's the same */
409		}
410		if (ifra->ifra_addr.sin_family == AF_INET &&
411		    (hostIsNew || maskIsNew))
412			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
413		if ((ifp->if_flags & IFF_BROADCAST) &&
414		    (ifra->ifra_broadaddr.sin_family == AF_INET))
415			ia->ia_broadaddr = ifra->ifra_broadaddr;
416		return (error);
417
418	case SIOCDIFADDR:
419		in_ifscrub(ifp, ia);
420		/*
421		 * Protect from ipintr() traversing address list
422		 * while we're modifying it.
423		 */
424		s = splnet();
425
426		ifa = &ia->ia_ifa;
427		TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
428		oia = ia;
429		TAILQ_REMOVE(&in_ifaddrhead, oia, ia_link);
430		IFAFREE(&oia->ia_ifa);
431		splx(s);
432		break;
433
434	default:
435		if (ifp == 0 || ifp->if_ioctl == 0)
436			return (EOPNOTSUPP);
437		return ((*ifp->if_ioctl)(ifp, cmd, data));
438	}
439	return (0);
440}
441
442/*
443 * SIOC[GAD]LIFADDR.
444 *	SIOCGLIFADDR: get first address. (?!?)
445 *	SIOCGLIFADDR with IFLR_PREFIX:
446 *		get first address that matches the specified prefix.
447 *	SIOCALIFADDR: add the specified address.
448 *	SIOCALIFADDR with IFLR_PREFIX:
449 *		EINVAL since we can't deduce hostid part of the address.
450 *	SIOCDLIFADDR: delete the specified address.
451 *	SIOCDLIFADDR with IFLR_PREFIX:
452 *		delete the first address that matches the specified prefix.
453 * return values:
454 *	EINVAL on invalid parameters
455 *	EADDRNOTAVAIL on prefix match failed/specified address not found
456 *	other values may be returned from in_ioctl()
457 */
458static int
459in_lifaddr_ioctl(so, cmd, data, ifp, p)
460	struct socket *so;
461	u_long cmd;
462	caddr_t	data;
463	struct ifnet *ifp;
464	struct proc *p;
465{
466	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
467	struct ifaddr *ifa;
468
469	/* sanity checks */
470	if (!data || !ifp) {
471		panic("invalid argument to in_lifaddr_ioctl");
472		/*NOTRECHED*/
473	}
474
475	switch (cmd) {
476	case SIOCGLIFADDR:
477		/* address must be specified on GET with IFLR_PREFIX */
478		if ((iflr->flags & IFLR_PREFIX) == 0)
479			break;
480		/*FALLTHROUGH*/
481	case SIOCALIFADDR:
482	case SIOCDLIFADDR:
483		/* address must be specified on ADD and DELETE */
484		if (iflr->addr.ss_family != AF_INET)
485			return EINVAL;
486		if (iflr->addr.ss_len != sizeof(struct sockaddr_in))
487			return EINVAL;
488		/* XXX need improvement */
489		if (iflr->dstaddr.ss_family
490		 && iflr->dstaddr.ss_family != AF_INET)
491			return EINVAL;
492		if (iflr->dstaddr.ss_family
493		 && iflr->dstaddr.ss_len != sizeof(struct sockaddr_in))
494			return EINVAL;
495		break;
496	default: /*shouldn't happen*/
497		return EOPNOTSUPP;
498	}
499	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
500		return EINVAL;
501
502	switch (cmd) {
503	case SIOCALIFADDR:
504	    {
505		struct in_aliasreq ifra;
506
507		if (iflr->flags & IFLR_PREFIX)
508			return EINVAL;
509
510		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
511		bzero(&ifra, sizeof(ifra));
512		bcopy(iflr->iflr_name, ifra.ifra_name,
513			sizeof(ifra.ifra_name));
514
515		bcopy(&iflr->addr, &ifra.ifra_addr, iflr->addr.ss_len);
516
517		if (iflr->dstaddr.ss_family) {	/*XXX*/
518			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
519				iflr->dstaddr.ss_len);
520		}
521
522		ifra.ifra_mask.sin_family = AF_INET;
523		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
524		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
525
526		return in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, p);
527	    }
528	case SIOCGLIFADDR:
529	case SIOCDLIFADDR:
530	    {
531		struct in_ifaddr *ia;
532		struct in_addr mask, candidate, match;
533		struct sockaddr_in *sin;
534		int cmp;
535
536		bzero(&mask, sizeof(mask));
537		if (iflr->flags & IFLR_PREFIX) {
538			/* lookup a prefix rather than address. */
539			in_len2mask(&mask, iflr->prefixlen);
540
541			sin = (struct sockaddr_in *)&iflr->addr;
542			match.s_addr = sin->sin_addr.s_addr;
543			match.s_addr &= mask.s_addr;
544
545			/* if you set extra bits, that's wrong */
546			if (match.s_addr != sin->sin_addr.s_addr)
547				return EINVAL;
548
549			cmp = 1;
550		} else {
551			if (cmd == SIOCGLIFADDR) {
552				/* on getting an address, take the 1st match */
553				cmp = 0;	/*XXX*/
554			} else {
555				/* on deleting an address, do exact match */
556				in_len2mask(&mask, 32);
557				sin = (struct sockaddr_in *)&iflr->addr;
558				match.s_addr = sin->sin_addr.s_addr;
559
560				cmp = 1;
561			}
562		}
563
564		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)	{
565			if (ifa->ifa_addr->sa_family != AF_INET6)
566				continue;
567			if (!cmp)
568				break;
569			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
570			candidate.s_addr &= mask.s_addr;
571			if (candidate.s_addr == match.s_addr)
572				break;
573		}
574		if (!ifa)
575			return EADDRNOTAVAIL;
576		ia = (struct in_ifaddr *)ifa;
577
578		if (cmd == SIOCGLIFADDR) {
579			/* fill in the if_laddrreq structure */
580			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
581
582			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
583				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
584					ia->ia_dstaddr.sin_len);
585			} else
586				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
587
588			iflr->prefixlen =
589				in_mask2len(&ia->ia_sockmask.sin_addr);
590
591			iflr->flags = 0;	/*XXX*/
592
593			return 0;
594		} else {
595			struct in_aliasreq ifra;
596
597			/* fill in_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
598			bzero(&ifra, sizeof(ifra));
599			bcopy(iflr->iflr_name, ifra.ifra_name,
600				sizeof(ifra.ifra_name));
601
602			bcopy(&ia->ia_addr, &ifra.ifra_addr,
603				ia->ia_addr.sin_len);
604			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
605				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
606					ia->ia_dstaddr.sin_len);
607			}
608			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
609				ia->ia_sockmask.sin_len);
610
611			return in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
612					  ifp, p);
613		}
614	    }
615	}
616
617	return EOPNOTSUPP;	/*just for safety*/
618}
619
620/*
621 * Delete any existing route for an interface.
622 */
623void
624in_ifscrub(ifp, ia)
625	register struct ifnet *ifp;
626	register struct in_ifaddr *ia;
627{
628
629	if ((ia->ia_flags & IFA_ROUTE) == 0)
630		return;
631	if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
632		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
633	else
634		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
635	ia->ia_flags &= ~IFA_ROUTE;
636}
637
638/*
639 * Initialize an interface's internet address
640 * and routing table entry.
641 */
642static int
643in_ifinit(ifp, ia, sin, scrub)
644	register struct ifnet *ifp;
645	register struct in_ifaddr *ia;
646	struct sockaddr_in *sin;
647	int scrub;
648{
649	register u_long i = ntohl(sin->sin_addr.s_addr);
650	struct sockaddr_in oldaddr;
651	int s = splimp(), flags = RTF_UP, error;
652
653	oldaddr = ia->ia_addr;
654	ia->ia_addr = *sin;
655	/*
656	 * Give the interface a chance to initialize
657	 * if this is its first address,
658	 * and to validate the address if necessary.
659	 */
660	if (ifp->if_ioctl &&
661	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
662		splx(s);
663		ia->ia_addr = oldaddr;
664		return (error);
665	}
666	splx(s);
667	if (scrub) {
668		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
669		in_ifscrub(ifp, ia);
670		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
671	}
672	if (IN_CLASSA(i))
673		ia->ia_netmask = IN_CLASSA_NET;
674	else if (IN_CLASSB(i))
675		ia->ia_netmask = IN_CLASSB_NET;
676	else
677		ia->ia_netmask = IN_CLASSC_NET;
678	/*
679	 * The subnet mask usually includes at least the standard network part,
680	 * but may may be smaller in the case of supernetting.
681	 * If it is set, we believe it.
682	 */
683	if (ia->ia_subnetmask == 0) {
684		ia->ia_subnetmask = ia->ia_netmask;
685		ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
686	} else
687		ia->ia_netmask &= ia->ia_subnetmask;
688	ia->ia_net = i & ia->ia_netmask;
689	ia->ia_subnet = i & ia->ia_subnetmask;
690	in_socktrim(&ia->ia_sockmask);
691	/*
692	 * Add route for the network.
693	 */
694	ia->ia_ifa.ifa_metric = ifp->if_metric;
695	if (ifp->if_flags & IFF_BROADCAST) {
696		ia->ia_broadaddr.sin_addr.s_addr =
697			htonl(ia->ia_subnet | ~ia->ia_subnetmask);
698		ia->ia_netbroadcast.s_addr =
699			htonl(ia->ia_net | ~ ia->ia_netmask);
700	} else if (ifp->if_flags & IFF_LOOPBACK) {
701		ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
702		flags |= RTF_HOST;
703	} else if (ifp->if_flags & IFF_POINTOPOINT) {
704		if (ia->ia_dstaddr.sin_family != AF_INET)
705			return (0);
706		flags |= RTF_HOST;
707	}
708	if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD, flags)) == 0)
709		ia->ia_flags |= IFA_ROUTE;
710
711	/*
712	 * If the interface supports multicast, join the "all hosts"
713	 * multicast group on that interface.
714	 */
715	if (ifp->if_flags & IFF_MULTICAST) {
716		struct in_addr addr;
717
718		addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
719		in_addmulti(&addr, ifp);
720	}
721	return (error);
722}
723
724
725/*
726 * Return 1 if the address might be a local broadcast address.
727 */
728int
729in_broadcast(in, ifp)
730	struct in_addr in;
731        struct ifnet *ifp;
732{
733	register struct ifaddr *ifa;
734	u_long t;
735
736	if (in.s_addr == INADDR_BROADCAST ||
737	    in.s_addr == INADDR_ANY)
738		return 1;
739	if ((ifp->if_flags & IFF_BROADCAST) == 0)
740		return 0;
741	t = ntohl(in.s_addr);
742	/*
743	 * Look through the list of addresses for a match
744	 * with a broadcast address.
745	 */
746#define ia ((struct in_ifaddr *)ifa)
747	for (ifa = ifp->if_addrhead.tqh_first; ifa;
748	     ifa = ifa->ifa_link.tqe_next)
749		if (ifa->ifa_addr->sa_family == AF_INET &&
750		    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
751		     in.s_addr == ia->ia_netbroadcast.s_addr ||
752		     /*
753		      * Check for old-style (host 0) broadcast.
754		      */
755		     t == ia->ia_subnet || t == ia->ia_net) &&
756		     /*
757		      * Check for an all one subnetmask. These
758		      * only exist when an interface gets a secondary
759		      * address.
760		      */
761		     ia->ia_subnetmask != (u_long)0xffffffff)
762			    return 1;
763	return (0);
764#undef ia
765}
766/*
767 * Add an address to the list of IP multicast addresses for a given interface.
768 */
769struct in_multi *
770in_addmulti(ap, ifp)
771	register struct in_addr *ap;
772	register struct ifnet *ifp;
773{
774	register struct in_multi *inm;
775	int error;
776	struct sockaddr_in sin;
777	struct ifmultiaddr *ifma;
778	int s = splnet();
779
780	/*
781	 * Call generic routine to add membership or increment
782	 * refcount.  It wants addresses in the form of a sockaddr,
783	 * so we build one here (being careful to zero the unused bytes).
784	 */
785	bzero(&sin, sizeof sin);
786	sin.sin_family = AF_INET;
787	sin.sin_len = sizeof sin;
788	sin.sin_addr = *ap;
789	error = if_addmulti(ifp, (struct sockaddr *)&sin, &ifma);
790	if (error) {
791		splx(s);
792		return 0;
793	}
794
795	/*
796	 * If ifma->ifma_protospec is null, then if_addmulti() created
797	 * a new record.  Otherwise, we are done.
798	 */
799	if (ifma->ifma_protospec != 0) {
800		splx(s);
801		return ifma->ifma_protospec;
802	}
803
804	/* XXX - if_addmulti uses M_WAITOK.  Can this really be called
805	   at interrupt time?  If so, need to fix if_addmulti. XXX */
806	inm = (struct in_multi *)malloc(sizeof(*inm), M_IPMADDR, M_NOWAIT);
807	if (inm == NULL) {
808		splx(s);
809		return (NULL);
810	}
811
812	bzero(inm, sizeof *inm);
813	inm->inm_addr = *ap;
814	inm->inm_ifp = ifp;
815	inm->inm_ifma = ifma;
816	ifma->ifma_protospec = inm;
817	LIST_INSERT_HEAD(&in_multihead, inm, inm_link);
818
819	/*
820	 * Let IGMP know that we have joined a new IP multicast group.
821	 */
822	igmp_joingroup(inm);
823	splx(s);
824	return (inm);
825}
826
827/*
828 * Delete a multicast address record.
829 */
830void
831in_delmulti(inm)
832	register struct in_multi *inm;
833{
834	struct ifmultiaddr *ifma = inm->inm_ifma;
835	struct in_multi my_inm;
836	int s = splnet();
837
838	my_inm.inm_ifp = NULL ; /* don't send the leave msg */
839	if (ifma->ifma_refcount == 1) {
840		/*
841		 * No remaining claims to this record; let IGMP know that
842		 * we are leaving the multicast group.
843		 * But do it after the if_delmulti() which might reset
844		 * the interface and nuke the packet.
845		 */
846		my_inm = *inm ;
847		ifma->ifma_protospec = 0;
848		LIST_REMOVE(inm, inm_link);
849		free(inm, M_IPMADDR);
850	}
851	/* XXX - should be separate API for when we have an ifma? */
852	if_delmulti(ifma->ifma_ifp, ifma->ifma_addr);
853	if (my_inm.inm_ifp != NULL)
854		igmp_leavegroup(&my_inm);
855	splx(s);
856}
857