xref: /freebsd/sys/net/if_ethersubr.c (revision ef5d438ed4bc17ad7ece3e40fe4d1f9baf3aadf7)
1 /*
2  * Copyright (c) 1982, 1989, 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  *	@(#)if_ethersubr.c	8.1 (Berkeley) 6/10/93
34  * $Id: if_ethersubr.c,v 1.13 1995/12/20 21:53:40 wollman Exp $
35  */
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/kernel.h>
40 #include <sys/malloc.h>
41 #include <sys/mbuf.h>
42 #include <sys/protosw.h>
43 #include <sys/socket.h>
44 #include <sys/ioctl.h>
45 #include <sys/errno.h>
46 #include <sys/syslog.h>
47 #include <sys/sysctl.h>
48 
49 #include <machine/cpu.h>
50 
51 #include <net/if.h>
52 #include <net/netisr.h>
53 #include <net/route.h>
54 #include <net/if_llc.h>
55 #include <net/if_dl.h>
56 #include <net/if_types.h>
57 
58 #ifdef INET
59 #include <netinet/in.h>
60 #include <netinet/in_var.h>
61 #endif
62 #include <netinet/if_ether.h>
63 
64 #ifdef IPX
65 #include <netipx/ipx.h>
66 #include <netipx/ipx_if.h>
67 #endif
68 
69 #ifdef NS
70 #include <netns/ns.h>
71 #include <netns/ns_if.h>
72 #endif
73 
74 #ifdef ISO
75 #include <netiso/argo_debug.h>
76 #include <netiso/iso.h>
77 #include <netiso/iso_var.h>
78 #include <netiso/iso_snpac.h>
79 #endif
80 
81 #ifdef LLC
82 #include <netccitt/dll.h>
83 #include <netccitt/llc_var.h>
84 #endif
85 
86 #if defined(LLC) && defined(CCITT)
87 extern struct ifqueue pkintrq;
88 #endif
89 
90 u_char	etherbroadcastaddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
91 #define senderr(e) { error = (e); goto bad;}
92 
93 /*
94  * Ethernet output routine.
95  * Encapsulate a packet of type family for the local net.
96  * Use trailer local net encapsulation if enough data in first
97  * packet leaves a multiple of 512 bytes of data in remainder.
98  * Assumes that ifp is actually pointer to arpcom structure.
99  */
100 int
101 ether_output(ifp, m0, dst, rt0)
102 	register struct ifnet *ifp;
103 	struct mbuf *m0;
104 	struct sockaddr *dst;
105 	struct rtentry *rt0;
106 {
107 	short type;
108 	int s, error = 0;
109  	u_char edst[6];
110 	register struct mbuf *m = m0;
111 	register struct rtentry *rt;
112 	struct mbuf *mcopy = (struct mbuf *)0;
113 	register struct ether_header *eh;
114 	int off, len = m->m_pkthdr.len;
115 	struct arpcom *ac = (struct arpcom *)ifp;
116 
117 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
118 		senderr(ENETDOWN);
119 	ifp->if_lastchange = time;
120 	rt = rt0;
121 	if (rt) {
122 		if ((rt->rt_flags & RTF_UP) == 0) {
123 			rt0 = rt = rtalloc1(dst, 1, 0UL);
124 			if (rt0)
125 				rt->rt_refcnt--;
126 			else
127 				senderr(EHOSTUNREACH);
128 		}
129 		if (rt->rt_flags & RTF_GATEWAY) {
130 			if (rt->rt_gwroute == 0)
131 				goto lookup;
132 			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
133 				rtfree(rt); rt = rt0;
134 			lookup: rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1,
135 							  0UL);
136 				if ((rt = rt->rt_gwroute) == 0)
137 					senderr(EHOSTUNREACH);
138 			}
139 		}
140 		if (rt->rt_flags & RTF_REJECT)
141 			if (rt->rt_rmx.rmx_expire == 0 ||
142 			    time.tv_sec < rt->rt_rmx.rmx_expire)
143 				senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
144 	}
145 	switch (dst->sa_family) {
146 
147 #ifdef INET
148 	case AF_INET:
149 		if (!arpresolve(ac, rt, m, dst, edst, rt0))
150 			return (0);	/* if not yet resolved */
151 		/* If broadcasting on a simplex interface, loopback a copy */
152 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
153 			mcopy = m_copy(m, 0, (int)M_COPYALL);
154 		off = m->m_pkthdr.len - m->m_len;
155 		type = ETHERTYPE_IP;
156 		break;
157 #endif
158 #ifdef IPX
159 	case AF_IPX:
160 		type = ETHERTYPE_IPX;
161  		bcopy((caddr_t)&(((struct sockaddr_ipx *)dst)->sipx_addr.x_host),
162 		    (caddr_t)edst, sizeof (edst));
163 		if (!bcmp((caddr_t)edst, (caddr_t)&ipx_thishost, sizeof(edst)))
164 			return (looutput(ifp, m, dst, rt));
165 		/* If broadcasting on a simplex interface, loopback a copy */
166 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
167 			mcopy = m_copy(m, 0, (int)M_COPYALL);
168 		break;
169 #endif
170 #ifdef NS
171 	case AF_NS:
172 		type = ETHERTYPE_NS;
173  		bcopy((caddr_t)&(((struct sockaddr_ns *)dst)->sns_addr.x_host),
174 		    (caddr_t)edst, sizeof (edst));
175 		if (!bcmp((caddr_t)edst, (caddr_t)&ns_thishost, sizeof(edst)))
176 			return (looutput(ifp, m, dst, rt));
177 		/* If broadcasting on a simplex interface, loopback a copy */
178 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
179 			mcopy = m_copy(m, 0, (int)M_COPYALL);
180 		break;
181 #endif
182 #ifdef	ISO
183 	case AF_ISO: {
184 		int	snpalen;
185 		struct	llc *l;
186 		register struct sockaddr_dl *sdl;
187 
188 		if (rt && (sdl = (struct sockaddr_dl *)rt->rt_gateway) &&
189 		    sdl->sdl_family == AF_LINK && sdl->sdl_alen > 0) {
190 			bcopy(LLADDR(sdl), (caddr_t)edst, sizeof(edst));
191 		} else if (error =
192 			    iso_snparesolve(ifp, (struct sockaddr_iso *)dst,
193 					    (char *)edst, &snpalen))
194 			goto bad; /* Not Resolved */
195 		/* If broadcasting on a simplex interface, loopback a copy */
196 		if (*edst & 1)
197 			m->m_flags |= (M_BCAST|M_MCAST);
198 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX) &&
199 		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
200 			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
201 			if (mcopy) {
202 				eh = mtod(mcopy, struct ether_header *);
203 				bcopy((caddr_t)edst,
204 				      (caddr_t)eh->ether_dhost, sizeof (edst));
205 				bcopy((caddr_t)ac->ac_enaddr,
206 				      (caddr_t)eh->ether_shost, sizeof (edst));
207 			}
208 		}
209 		M_PREPEND(m, 3, M_DONTWAIT);
210 		if (m == NULL)
211 			return (0);
212 		type = m->m_pkthdr.len;
213 		l = mtod(m, struct llc *);
214 		l->llc_dsap = l->llc_ssap = LLC_ISO_LSAP;
215 		l->llc_control = LLC_UI;
216 		len += 3;
217 		IFDEBUG(D_ETHER)
218 			int i;
219 			printf("unoutput: sending pkt to: ");
220 			for (i=0; i<6; i++)
221 				printf("%x ", edst[i] & 0xff);
222 			printf("\n");
223 		ENDDEBUG
224 		} break;
225 #endif /* ISO */
226 #ifdef	LLC
227 /*	case AF_NSAP: */
228 	case AF_CCITT: {
229 		register struct sockaddr_dl *sdl =
230 			(struct sockaddr_dl *) rt -> rt_gateway;
231 
232 		if (sdl && sdl->sdl_family == AF_LINK
233 		    && sdl->sdl_alen > 0) {
234 			bcopy(LLADDR(sdl), (char *)edst,
235 				sizeof(edst));
236 		} else goto bad; /* Not a link interface ? Funny ... */
237 		if ((ifp->if_flags & IFF_SIMPLEX) && (*edst & 1) &&
238 		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
239 			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
240 			if (mcopy) {
241 				eh = mtod(mcopy, struct ether_header *);
242 				bcopy((caddr_t)edst,
243 				      (caddr_t)eh->ether_dhost, sizeof (edst));
244 				bcopy((caddr_t)ac->ac_enaddr,
245 				      (caddr_t)eh->ether_shost, sizeof (edst));
246 			}
247 		}
248 		type = m->m_pkthdr.len;
249 #ifdef LLC_DEBUG
250 		{
251 			int i;
252 			register struct llc *l = mtod(m, struct llc *);
253 
254 			printf("ether_output: sending LLC2 pkt to: ");
255 			for (i=0; i<6; i++)
256 				printf("%x ", edst[i] & 0xff);
257 			printf(" len 0x%x dsap 0x%x ssap 0x%x control 0x%x\n",
258 			       type & 0xff, l->llc_dsap & 0xff, l->llc_ssap &0xff,
259 			       l->llc_control & 0xff);
260 
261 		}
262 #endif /* LLC_DEBUG */
263 		} break;
264 #endif /* LLC */
265 
266 	case AF_UNSPEC:
267 		eh = (struct ether_header *)dst->sa_data;
268  		(void)memcpy(edst, eh->ether_dhost, sizeof (edst));
269 		type = eh->ether_type;
270 		break;
271 
272 	default:
273 		printf("%s%d: can't handle af%d\n", ifp->if_name, ifp->if_unit,
274 			dst->sa_family);
275 		senderr(EAFNOSUPPORT);
276 	}
277 
278 
279 	if (mcopy)
280 		(void) looutput(ifp, mcopy, dst, rt);
281 	/*
282 	 * Add local net header.  If no space in first mbuf,
283 	 * allocate another.
284 	 */
285 	M_PREPEND(m, sizeof (struct ether_header), M_DONTWAIT);
286 	if (m == 0)
287 		senderr(ENOBUFS);
288 	eh = mtod(m, struct ether_header *);
289 	type = htons((u_short)type);
290 	(void)memcpy(&eh->ether_type, &type,
291 		sizeof(eh->ether_type));
292  	(void)memcpy(eh->ether_dhost, edst, sizeof (edst));
293  	(void)memcpy(eh->ether_shost, ac->ac_enaddr,
294 	    sizeof(eh->ether_shost));
295 	s = splimp();
296 	/*
297 	 * Queue message on interface, and start output if interface
298 	 * not yet active.
299 	 */
300 	if (IF_QFULL(&ifp->if_snd)) {
301 		IF_DROP(&ifp->if_snd);
302 		splx(s);
303 		senderr(ENOBUFS);
304 	}
305 	IF_ENQUEUE(&ifp->if_snd, m);
306 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
307 		(*ifp->if_start)(ifp);
308 	splx(s);
309 	ifp->if_obytes += len + sizeof (struct ether_header);
310 	if (m->m_flags & M_MCAST)
311 		ifp->if_omcasts++;
312 	return (error);
313 
314 bad:
315 	if (m)
316 		m_freem(m);
317 	return (error);
318 }
319 
320 /*
321  * Process a received Ethernet packet;
322  * the packet is in the mbuf chain m without
323  * the ether header, which is provided separately.
324  */
325 void
326 ether_input(ifp, eh, m)
327 	struct ifnet *ifp;
328 	register struct ether_header *eh;
329 	struct mbuf *m;
330 {
331 	register struct ifqueue *inq;
332 	register struct llc *l;
333 	u_short ether_type;
334 	int s;
335 
336 	if ((ifp->if_flags & IFF_UP) == 0) {
337 		m_freem(m);
338 		return;
339 	}
340 	ifp->if_lastchange = time;
341 	ifp->if_ibytes += m->m_pkthdr.len + sizeof (*eh);
342 	if (bcmp((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
343 	    sizeof(etherbroadcastaddr)) == 0)
344 		m->m_flags |= M_BCAST;
345 	else if (eh->ether_dhost[0] & 1)
346 		m->m_flags |= M_MCAST;
347 	if (m->m_flags & (M_BCAST|M_MCAST))
348 		ifp->if_imcasts++;
349 
350 	ether_type = ntohs(eh->ether_type);
351 
352 	switch (ether_type) {
353 #ifdef INET
354 	case ETHERTYPE_IP:
355 		schednetisr(NETISR_IP);
356 		inq = &ipintrq;
357 		break;
358 
359 	case ETHERTYPE_ARP:
360 		schednetisr(NETISR_ARP);
361 		inq = &arpintrq;
362 		break;
363 #endif
364 #ifdef IPX
365 	case ETHERTYPE_IPX:
366 		schednetisr(NETISR_IPX);
367 		inq = &ipxintrq;
368 		break;
369 #endif
370 #ifdef NS
371 	case ETHERTYPE_NS:
372 		schednetisr(NETISR_NS);
373 		inq = &nsintrq;
374 		break;
375 #endif
376 	default:
377 #if defined (ISO) || defined (LLC)
378 		if (ether_type > ETHERMTU)
379 			goto dropanyway;
380 		l = mtod(m, struct llc *);
381 		switch (l->llc_dsap) {
382 #ifdef	ISO
383 		case LLC_ISO_LSAP:
384 			switch (l->llc_control) {
385 			case LLC_UI:
386 				/* LLC_UI_P forbidden in class 1 service */
387 				if ((l->llc_dsap == LLC_ISO_LSAP) &&
388 				    (l->llc_ssap == LLC_ISO_LSAP)) {
389 					/* LSAP for ISO */
390 					if (m->m_pkthdr.len > ether_type)
391 						m_adj(m, ether_type - m->m_pkthdr.len);
392 					m->m_data += 3;		/* XXX */
393 					m->m_len -= 3;		/* XXX */
394 					m->m_pkthdr.len -= 3;	/* XXX */
395 					M_PREPEND(m, sizeof *eh, M_DONTWAIT);
396 					if (m == 0)
397 						return;
398 					*mtod(m, struct ether_header *) = *eh;
399 					IFDEBUG(D_ETHER)
400 						printf("clnp packet");
401 					ENDDEBUG
402 					schednetisr(NETISR_ISO);
403 					inq = &clnlintrq;
404 					break;
405 				}
406 				goto dropanyway;
407 
408 			case LLC_XID:
409 			case LLC_XID_P:
410 				if(m->m_len < 6)
411 					goto dropanyway;
412 				l->llc_window = 0;
413 				l->llc_fid = 9;
414 				l->llc_class = 1;
415 				l->llc_dsap = l->llc_ssap = 0;
416 				/* Fall through to */
417 			case LLC_TEST:
418 			case LLC_TEST_P:
419 			{
420 				struct sockaddr sa;
421 				register struct ether_header *eh2;
422 				int i;
423 				u_char c = l->llc_dsap;
424 
425 				l->llc_dsap = l->llc_ssap;
426 				l->llc_ssap = c;
427 				if (m->m_flags & (M_BCAST | M_MCAST))
428 					bcopy((caddr_t)ac->ac_enaddr,
429 					      (caddr_t)eh->ether_dhost, 6);
430 				sa.sa_family = AF_UNSPEC;
431 				sa.sa_len = sizeof(sa);
432 				eh2 = (struct ether_header *)sa.sa_data;
433 				for (i = 0; i < 6; i++) {
434 					eh2->ether_shost[i] = c = eh->ether_dhost[i];
435 					eh2->ether_dhost[i] =
436 						eh->ether_dhost[i] = eh->ether_shost[i];
437 					eh->ether_shost[i] = c;
438 				}
439 				ifp->if_output(ifp, m, &sa, NULL);
440 				return;
441 			}
442 			default:
443 				m_freem(m);
444 				return;
445 			}
446 			break;
447 #endif /* ISO */
448 #ifdef LLC
449 		case LLC_X25_LSAP:
450 		{
451 			if (m->m_pkthdr.len > ether_type)
452 				m_adj(m, ether_type - m->m_pkthdr.len);
453 			M_PREPEND(m, sizeof(struct sdl_hdr) , M_DONTWAIT);
454 			if (m == 0)
455 				return;
456 			if ( !sdl_sethdrif(ifp, eh->ether_shost, LLC_X25_LSAP,
457 					    eh->ether_dhost, LLC_X25_LSAP, 6,
458 					    mtod(m, struct sdl_hdr *)))
459 				panic("ETHER cons addr failure");
460 			mtod(m, struct sdl_hdr *)->sdlhdr_len = ether_type;
461 #ifdef LLC_DEBUG
462 				printf("llc packet\n");
463 #endif /* LLC_DEBUG */
464 			schednetisr(NETISR_CCITT);
465 			inq = &llcintrq;
466 			break;
467 		}
468 #endif /* LLC */
469 		dropanyway:
470 		default:
471 			m_freem(m);
472 			return;
473 		}
474 #else /* ISO || LLC */
475 	    m_freem(m);
476 	    return;
477 #endif /* ISO || LLC */
478 	}
479 
480 	s = splimp();
481 	if (IF_QFULL(inq)) {
482 		IF_DROP(inq);
483 		m_freem(m);
484 	} else
485 		IF_ENQUEUE(inq, m);
486 	splx(s);
487 }
488 
489 /*
490  * Perform common duties while attaching to interface list
491  */
492 void
493 ether_ifattach(ifp)
494 	register struct ifnet *ifp;
495 {
496 	register struct ifaddr *ifa;
497 	register struct sockaddr_dl *sdl;
498 
499 	ifp->if_type = IFT_ETHER;
500 	ifp->if_addrlen = 6;
501 	ifp->if_hdrlen = 14;
502 	ifp->if_mtu = ETHERMTU;
503 	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
504 		if ((sdl = (struct sockaddr_dl *)ifa->ifa_addr) &&
505 		    sdl->sdl_family == AF_LINK) {
506 			sdl->sdl_type = IFT_ETHER;
507 			sdl->sdl_alen = ifp->if_addrlen;
508 			bcopy((caddr_t)((struct arpcom *)ifp)->ac_enaddr,
509 			      LLADDR(sdl), ifp->if_addrlen);
510 			break;
511 		}
512 }
513 
514 static u_char ether_ipmulticast_min[6] =
515 	{ 0x01, 0x00, 0x5e, 0x00, 0x00, 0x00 };
516 static u_char ether_ipmulticast_max[6] =
517 	{ 0x01, 0x00, 0x5e, 0x7f, 0xff, 0xff };
518 /*
519  * Add an Ethernet multicast address or range of addresses to the list for a
520  * given interface.
521  */
522 int
523 ether_addmulti(ifr, ac)
524 	struct ifreq *ifr;
525 	register struct arpcom *ac;
526 {
527 	register struct ether_multi *enm;
528 	struct sockaddr_in *sin;
529 	u_char addrlo[6];
530 	u_char addrhi[6];
531       int set_allmulti = 0;
532 	int s = splimp();
533 
534 	switch (ifr->ifr_addr.sa_family) {
535 
536 	case AF_UNSPEC:
537 		bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
538 		bcopy(addrlo, addrhi, 6);
539 		break;
540 
541 #ifdef INET
542 	case AF_INET:
543 		sin = (struct sockaddr_in *)&(ifr->ifr_addr);
544 		if (sin->sin_addr.s_addr == INADDR_ANY) {
545 			/*
546 			 * An IP address of INADDR_ANY means listen to all
547 			 * of the Ethernet multicast addresses used for IP.
548 			 * (This is for the sake of IP multicast routers.)
549 			 */
550 			bcopy(ether_ipmulticast_min, addrlo, 6);
551 			bcopy(ether_ipmulticast_max, addrhi, 6);
552                       set_allmulti = 1;
553 		}
554 		else {
555 			ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
556 			bcopy(addrlo, addrhi, 6);
557 		}
558 		break;
559 #endif
560 
561 	default:
562 		splx(s);
563 		return (EAFNOSUPPORT);
564 	}
565 
566 	/*
567 	 * Verify that we have valid Ethernet multicast addresses.
568 	 */
569 	if ((addrlo[0] & 0x01) != 1 || (addrhi[0] & 0x01) != 1) {
570 		splx(s);
571 		return (EINVAL);
572 	}
573 	/*
574 	 * See if the address range is already in the list.
575 	 */
576 	ETHER_LOOKUP_MULTI(addrlo, addrhi, ac, enm);
577 	if (enm != NULL) {
578 		/*
579 		 * Found it; just increment the reference count.
580 		 */
581 		++enm->enm_refcount;
582 		splx(s);
583 		return (0);
584 	}
585 	/*
586 	 * New address or range; malloc a new multicast record
587 	 * and link it into the interface's multicast list.
588 	 */
589 	enm = (struct ether_multi *)malloc(sizeof(*enm), M_IFMADDR, M_NOWAIT);
590 	if (enm == NULL) {
591 		splx(s);
592 		return (ENOBUFS);
593 	}
594 	bcopy(addrlo, enm->enm_addrlo, 6);
595 	bcopy(addrhi, enm->enm_addrhi, 6);
596 	enm->enm_ac = ac;
597 	enm->enm_refcount = 1;
598 	enm->enm_next = ac->ac_multiaddrs;
599 	ac->ac_multiaddrs = enm;
600 	ac->ac_multicnt++;
601 	splx(s);
602       if (set_allmulti)
603               ac->ac_if.if_flags |= IFF_ALLMULTI;
604 
605 	/*
606 	 * Return ENETRESET to inform the driver that the list has changed
607 	 * and its reception filter should be adjusted accordingly.
608 	 */
609 	return (ENETRESET);
610 }
611 
612 /*
613  * Delete a multicast address record.
614  */
615 int
616 ether_delmulti(ifr, ac)
617 	struct ifreq *ifr;
618 	register struct arpcom *ac;
619 {
620 	register struct ether_multi *enm;
621 	register struct ether_multi **p;
622 	struct sockaddr_in *sin;
623 	u_char addrlo[6];
624 	u_char addrhi[6];
625       int unset_allmulti = 0;
626 	int s = splimp();
627 
628 	switch (ifr->ifr_addr.sa_family) {
629 
630 	case AF_UNSPEC:
631 		bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
632 		bcopy(addrlo, addrhi, 6);
633 		break;
634 
635 #ifdef INET
636 	case AF_INET:
637 		sin = (struct sockaddr_in *)&(ifr->ifr_addr);
638 		if (sin->sin_addr.s_addr == INADDR_ANY) {
639 			/*
640 			 * An IP address of INADDR_ANY means stop listening
641 			 * to the range of Ethernet multicast addresses used
642 			 * for IP.
643 			 */
644 			bcopy(ether_ipmulticast_min, addrlo, 6);
645 			bcopy(ether_ipmulticast_max, addrhi, 6);
646                       unset_allmulti = 1;
647 		}
648 		else {
649 			ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
650 			bcopy(addrlo, addrhi, 6);
651 		}
652 		break;
653 #endif
654 
655 	default:
656 		splx(s);
657 		return (EAFNOSUPPORT);
658 	}
659 
660 	/*
661 	 * Look up the address in our list.
662 	 */
663 	ETHER_LOOKUP_MULTI(addrlo, addrhi, ac, enm);
664 	if (enm == NULL) {
665 		splx(s);
666 		return (ENXIO);
667 	}
668 	if (--enm->enm_refcount != 0) {
669 		/*
670 		 * Still some claims to this record.
671 		 */
672 		splx(s);
673 		return (0);
674 	}
675 	/*
676 	 * No remaining claims to this record; unlink and free it.
677 	 */
678 	for (p = &enm->enm_ac->ac_multiaddrs;
679 	     *p != enm;
680 	     p = &(*p)->enm_next)
681 		continue;
682 	*p = (*p)->enm_next;
683 	free(enm, M_IFMADDR);
684 	ac->ac_multicnt--;
685 	splx(s);
686       if (unset_allmulti)
687               ac->ac_if.if_flags &= ~IFF_ALLMULTI;
688 
689 	/*
690 	 * Return ENETRESET to inform the driver that the list has changed
691 	 * and its reception filter should be adjusted accordingly.
692 	 */
693 	return (ENETRESET);
694 }
695 
696 SYSCTL_NODE(_net_link, IFT_ETHER, ether, CTLFLAG_RW, 0, "Ethernet");
697