xref: /netbsd-src/sys/net/if_ethersubr.c (revision 1f2744e6e4915c9da2a3f980279398c4cf7d5e6d)
1 /*	$NetBSD: if_ethersubr.c,v 1.10 1995/03/08 02:56:55 cgd Exp $	*/
2 
3 /*
4  * Copyright (c) 1982, 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)if_ethersubr.c	8.1 (Berkeley) 6/10/93
36  */
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
41 #include <sys/malloc.h>
42 #include <sys/mbuf.h>
43 #include <sys/protosw.h>
44 #include <sys/socket.h>
45 #include <sys/ioctl.h>
46 #include <sys/errno.h>
47 #include <sys/syslog.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 NS
65 #include <netns/ns.h>
66 #include <netns/ns_if.h>
67 #endif
68 
69 #ifdef ISO
70 #include <netiso/argo_debug.h>
71 #include <netiso/iso.h>
72 #include <netiso/iso_var.h>
73 #include <netiso/iso_snpac.h>
74 #endif
75 
76 #ifdef LLC
77 #include <netccitt/dll.h>
78 #include <netccitt/llc_var.h>
79 #endif
80 
81 #if defined(LLC) && defined(CCITT)
82 extern struct ifqueue pkintrq;
83 #endif
84 
85 u_char	etherbroadcastaddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
86 extern	struct ifnet loif;
87 #define senderr(e) { error = (e); goto bad;}
88 
89 /*
90  * Ethernet output routine.
91  * Encapsulate a packet of type family for the local net.
92  * Use trailer local net encapsulation if enough data in first
93  * packet leaves a multiple of 512 bytes of data in remainder.
94  * Assumes that ifp is actually pointer to arpcom structure.
95  */
96 int
97 ether_output(ifp, m0, dst, rt0)
98 	register struct ifnet *ifp;
99 	struct mbuf *m0;
100 	struct sockaddr *dst;
101 	struct rtentry *rt0;
102 {
103 	u_int16_t etype;
104 	int s, error = 0;
105  	u_char edst[6];
106 	register struct mbuf *m = m0;
107 	register struct rtentry *rt;
108 	struct mbuf *mcopy = (struct mbuf *)0;
109 	register struct ether_header *eh;
110 	int off, len = m->m_pkthdr.len;
111 	struct arpcom *ac = (struct arpcom *)ifp;
112 
113 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
114 		senderr(ENETDOWN);
115 	ifp->if_lastchange = time;
116 	if (rt = rt0) {
117 		if ((rt->rt_flags & RTF_UP) == 0) {
118 			if (rt0 = rt = rtalloc1(dst, 1))
119 				rt->rt_refcnt--;
120 			else
121 				senderr(EHOSTUNREACH);
122 		}
123 		if (rt->rt_flags & RTF_GATEWAY) {
124 			if (rt->rt_gwroute == 0)
125 				goto lookup;
126 			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
127 				rtfree(rt); rt = rt0;
128 			lookup: rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1);
129 				if ((rt = rt->rt_gwroute) == 0)
130 					senderr(EHOSTUNREACH);
131 			}
132 		}
133 		if (rt->rt_flags & RTF_REJECT)
134 			if (rt->rt_rmx.rmx_expire == 0 ||
135 			    time.tv_sec < rt->rt_rmx.rmx_expire)
136 				senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
137 	}
138 	switch (dst->sa_family) {
139 
140 #ifdef INET
141 	case AF_INET:
142 		if (!arpresolve(ac, rt, m, dst, edst))
143 			return (0);	/* if not yet resolved */
144 		/* If broadcasting on a simplex interface, loopback a copy */
145 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
146 			mcopy = m_copy(m, 0, (int)M_COPYALL);
147 		off = m->m_pkthdr.len - m->m_len;
148 		etype = ETHERTYPE_IP;
149 		break;
150 #endif
151 #ifdef NS
152 	case AF_NS:
153 		etype = ETHERTYPE_NS;
154  		bcopy((caddr_t)&(((struct sockaddr_ns *)dst)->sns_addr.x_host),
155 		    (caddr_t)edst, sizeof (edst));
156 		if (!bcmp((caddr_t)edst, (caddr_t)&ns_thishost, sizeof(edst)))
157 			return (looutput(ifp, m, dst, rt));
158 		/* If broadcasting on a simplex interface, loopback a copy */
159 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
160 			mcopy = m_copy(m, 0, (int)M_COPYALL);
161 		break;
162 #endif
163 #ifdef	ISO
164 	case AF_ISO: {
165 		int	snpalen;
166 		struct	llc *l;
167 		register struct sockaddr_dl *sdl;
168 
169 		if (rt && (sdl = (struct sockaddr_dl *)rt->rt_gateway) &&
170 		    sdl->sdl_family == AF_LINK && sdl->sdl_alen > 0) {
171 			bcopy(LLADDR(sdl), (caddr_t)edst, sizeof(edst));
172 		} else if (error =
173 			    iso_snparesolve(ifp, (struct sockaddr_iso *)dst,
174 					    (char *)edst, &snpalen))
175 			goto bad; /* Not Resolved */
176 		/* If broadcasting on a simplex interface, loopback a copy */
177 		if (*edst & 1)
178 			m->m_flags |= (M_BCAST|M_MCAST);
179 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX) &&
180 		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
181 			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
182 			if (mcopy) {
183 				eh = mtod(mcopy, struct ether_header *);
184 				bcopy((caddr_t)edst,
185 				      (caddr_t)eh->ether_dhost, sizeof (edst));
186 				bcopy((caddr_t)ac->ac_enaddr,
187 				      (caddr_t)eh->ether_shost, sizeof (edst));
188 			}
189 		}
190 		M_PREPEND(m, 3, M_DONTWAIT);
191 		if (m == NULL)
192 			return (0);
193 		etype = m->m_pkthdr.len;
194 		l = mtod(m, struct llc *);
195 		l->llc_dsap = l->llc_ssap = LLC_ISO_LSAP;
196 		l->llc_control = LLC_UI;
197 		len += 3;
198 		IFDEBUG(D_ETHER)
199 			int i;
200 			printf("unoutput: sending pkt to: ");
201 			for (i=0; i<6; i++)
202 				printf("%x ", edst[i] & 0xff);
203 			printf("\n");
204 		ENDDEBUG
205 		} break;
206 #endif /* ISO */
207 #ifdef	LLC
208 /*	case AF_NSAP: */
209 	case AF_CCITT: {
210 		register struct sockaddr_dl *sdl =
211 			(struct sockaddr_dl *) rt -> rt_gateway;
212 
213 		if (sdl && sdl->sdl_family == AF_LINK
214 		    && sdl->sdl_alen > 0) {
215 			bcopy(LLADDR(sdl), (char *)edst,
216 				sizeof(edst));
217 		} else goto bad; /* Not a link interface ? Funny ... */
218 		if ((ifp->if_flags & IFF_SIMPLEX) && (*edst & 1) &&
219 		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
220 			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
221 			if (mcopy) {
222 				eh = mtod(mcopy, struct ether_header *);
223 				bcopy((caddr_t)edst,
224 				      (caddr_t)eh->ether_dhost, sizeof (edst));
225 				bcopy((caddr_t)ac->ac_enaddr,
226 				      (caddr_t)eh->ether_shost, sizeof (edst));
227 			}
228 		}
229 		etype = m->m_pkthdr.len;
230 #ifdef LLC_DEBUG
231 		{
232 			int i;
233 			register struct llc *l = mtod(m, struct llc *);
234 
235 			printf("ether_output: sending LLC2 pkt to: ");
236 			for (i=0; i<6; i++)
237 				printf("%x ", edst[i] & 0xff);
238 			printf(" len 0x%x dsap 0x%x ssap 0x%x control 0x%x\n",
239 			       etype & 0xff, l->llc_dsap & 0xff, l->llc_ssap &0xff,
240 			       l->llc_control & 0xff);
241 
242 		}
243 #endif /* LLC_DEBUG */
244 		} break;
245 #endif /* LLC */
246 
247 	case AF_UNSPEC:
248 		eh = (struct ether_header *)dst->sa_data;
249  		bcopy((caddr_t)eh->ether_dhost, (caddr_t)edst, sizeof (edst));
250 		/* AF_UNSPEC doesn't swap the byte order of the ether_type. */
251 		etype = ntohs(eh->ether_type);
252 		break;
253 
254 	default:
255 		printf("%s%d: can't handle af%d\n", ifp->if_name, ifp->if_unit,
256 			dst->sa_family);
257 		senderr(EAFNOSUPPORT);
258 	}
259 
260 
261 	if (mcopy)
262 		(void) looutput(ifp, mcopy, dst, rt);
263 	/*
264 	 * Add local net header.  If no space in first mbuf,
265 	 * allocate another.
266 	 */
267 	M_PREPEND(m, sizeof (struct ether_header), M_DONTWAIT);
268 	if (m == 0)
269 		senderr(ENOBUFS);
270 	eh = mtod(m, struct ether_header *);
271 	etype = htons(etype);
272 	bcopy((caddr_t)&etype,(caddr_t)&eh->ether_type,
273 		sizeof(eh->ether_type));
274  	bcopy((caddr_t)edst, (caddr_t)eh->ether_dhost, sizeof (edst));
275  	bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost,
276 	    sizeof(eh->ether_shost));
277 	s = splimp();
278 	/*
279 	 * Queue message on interface, and start output if interface
280 	 * not yet active.
281 	 */
282 	if (IF_QFULL(&ifp->if_snd)) {
283 		IF_DROP(&ifp->if_snd);
284 		splx(s);
285 		senderr(ENOBUFS);
286 	}
287 	IF_ENQUEUE(&ifp->if_snd, m);
288 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
289 		(*ifp->if_start)(ifp);
290 	splx(s);
291 	ifp->if_obytes += len + sizeof (struct ether_header);
292 	if (m->m_flags & M_MCAST)
293 		ifp->if_omcasts++;
294 	return (error);
295 
296 bad:
297 	if (m)
298 		m_freem(m);
299 	return (error);
300 }
301 
302 /*
303  * Process a received Ethernet packet;
304  * the packet is in the mbuf chain m without
305  * the ether header, which is provided separately.
306  */
307 void
308 ether_input(ifp, eh, m)
309 	struct ifnet *ifp;
310 	register struct ether_header *eh;
311 	struct mbuf *m;
312 {
313 	register struct ifqueue *inq;
314 	register struct llc *l;
315 	u_int16_t etype;
316 	struct arpcom *ac = (struct arpcom *)ifp;
317 	int s;
318 
319 	if ((ifp->if_flags & IFF_UP) == 0) {
320 		m_freem(m);
321 		return;
322 	}
323 	ifp->if_lastchange = time;
324 	ifp->if_ibytes += m->m_pkthdr.len + sizeof (*eh);
325 	if (eh->ether_dhost[0] & 1) {
326 		if (bcmp((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
327 		    sizeof(etherbroadcastaddr)) == 0)
328 			m->m_flags |= M_BCAST;
329 		else
330 			m->m_flags |= M_MCAST;
331 	}
332 	if (m->m_flags & (M_BCAST|M_MCAST))
333 		ifp->if_imcasts++;
334 
335 	etype = ntohs(eh->ether_type);
336 	switch (etype) {
337 #ifdef INET
338 	case ETHERTYPE_IP:
339 		schednetisr(NETISR_IP);
340 		inq = &ipintrq;
341 		break;
342 
343 	case ETHERTYPE_ARP:
344 		schednetisr(NETISR_ARP);
345 		inq = &arpintrq;
346 		break;
347 
348 	case ETHERTYPE_REVARP:
349 		revarpinput(m);	/* XXX queue? */
350 		return;
351 #endif
352 #ifdef NS
353 	case ETHERTYPE_NS:
354 		schednetisr(NETISR_NS);
355 		inq = &nsintrq;
356 		break;
357 
358 #endif
359 	default:
360 #if defined (ISO) || defined (LLC)
361 		if (eh->ether_type > ETHERMTU)
362 			goto dropanyway;
363 		l = mtod(m, struct llc *);
364 		switch (l->llc_dsap) {
365 #ifdef	ISO
366 		case LLC_ISO_LSAP:
367 			switch (l->llc_control) {
368 			case LLC_UI:
369 				/* LLC_UI_P forbidden in class 1 service */
370 				if ((l->llc_dsap == LLC_ISO_LSAP) &&
371 				    (l->llc_ssap == LLC_ISO_LSAP)) {
372 					/* LSAP for ISO */
373 					if (m->m_pkthdr.len > eh->ether_type)
374 						m_adj(m, eh->ether_type - m->m_pkthdr.len);
375 					m->m_data += 3;		/* XXX */
376 					m->m_len -= 3;		/* XXX */
377 					m->m_pkthdr.len -= 3;	/* XXX */
378 					M_PREPEND(m, sizeof *eh, M_DONTWAIT);
379 					if (m == 0)
380 						return;
381 					*mtod(m, struct ether_header *) = *eh;
382 					IFDEBUG(D_ETHER)
383 						printf("clnp packet");
384 					ENDDEBUG
385 					schednetisr(NETISR_ISO);
386 					inq = &clnlintrq;
387 					break;
388 				}
389 				goto dropanyway;
390 
391 			case LLC_XID:
392 			case LLC_XID_P:
393 				if(m->m_len < 6)
394 					goto dropanyway;
395 				l->llc_window = 0;
396 				l->llc_fid = 9;
397 				l->llc_class = 1;
398 				l->llc_dsap = l->llc_ssap = 0;
399 				/* Fall through to */
400 			case LLC_TEST:
401 			case LLC_TEST_P:
402 			{
403 				struct sockaddr sa;
404 				register struct ether_header *eh2;
405 				int i;
406 				u_char c = l->llc_dsap;
407 
408 				l->llc_dsap = l->llc_ssap;
409 				l->llc_ssap = c;
410 				if (m->m_flags & (M_BCAST | M_MCAST))
411 					bcopy((caddr_t)ac->ac_enaddr,
412 					      (caddr_t)eh->ether_dhost, 6);
413 				sa.sa_family = AF_UNSPEC;
414 				sa.sa_len = sizeof(sa);
415 				eh2 = (struct ether_header *)sa.sa_data;
416 				for (i = 0; i < 6; i++) {
417 					eh2->ether_shost[i] = c = eh->ether_dhost[i];
418 					eh2->ether_dhost[i] =
419 						eh->ether_dhost[i] = eh->ether_shost[i];
420 					eh->ether_shost[i] = c;
421 				}
422 				ifp->if_output(ifp, m, &sa, NULL);
423 				return;
424 			}
425 			default:
426 				m_freem(m);
427 				return;
428 			}
429 			break;
430 #endif /* ISO */
431 #ifdef LLC
432 		case LLC_X25_LSAP:
433 		{
434 			if (m->m_pkthdr.len > eh->ether_type)
435 				m_adj(m, eh->ether_type - m->m_pkthdr.len);
436 			M_PREPEND(m, sizeof(struct sdl_hdr) , M_DONTWAIT);
437 			if (m == 0)
438 				return;
439 			if ( !sdl_sethdrif(ifp, eh->ether_shost, LLC_X25_LSAP,
440 					    eh->ether_dhost, LLC_X25_LSAP, 6,
441 					    mtod(m, struct sdl_hdr *)))
442 				panic("ETHER cons addr failure");
443 			mtod(m, struct sdl_hdr *)->sdlhdr_len = eh->ether_type;
444 #ifdef LLC_DEBUG
445 				printf("llc packet\n");
446 #endif /* LLC_DEBUG */
447 			schednetisr(NETISR_CCITT);
448 			inq = &llcintrq;
449 			break;
450 		}
451 #endif /* LLC */
452 		dropanyway:
453 		default:
454 			m_freem(m);
455 			return;
456 		}
457 #else /* ISO || LLC */
458 	    m_freem(m);
459 	    return;
460 #endif /* ISO || LLC */
461 	}
462 
463 	s = splimp();
464 	if (IF_QFULL(inq)) {
465 		IF_DROP(inq);
466 		m_freem(m);
467 	} else
468 		IF_ENQUEUE(inq, m);
469 	splx(s);
470 }
471 
472 /*
473  * Convert Ethernet address to printable (loggable) representation.
474  */
475 static char digits[] = "0123456789abcdef";
476 char *
477 ether_sprintf(ap)
478 	register u_char *ap;
479 {
480 	register i;
481 	static char etherbuf[18];
482 	register char *cp = etherbuf;
483 
484 	for (i = 0; i < 6; i++) {
485 		*cp++ = digits[*ap >> 4];
486 		*cp++ = digits[*ap++ & 0xf];
487 		*cp++ = ':';
488 	}
489 	*--cp = 0;
490 	return (etherbuf);
491 }
492 
493 /*
494  * Perform common duties while attaching to interface list
495  */
496 void
497 ether_ifattach(ifp)
498 	register struct ifnet *ifp;
499 {
500 	register struct ifaddr *ifa;
501 	register struct sockaddr_dl *sdl;
502 
503 	ifp->if_type = IFT_ETHER;
504 	ifp->if_addrlen = 6;
505 	ifp->if_hdrlen = 14;
506 	ifp->if_mtu = ETHERMTU;
507 	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
508 		if ((sdl = (struct sockaddr_dl *)ifa->ifa_addr) &&
509 		    sdl->sdl_family == AF_LINK) {
510 			sdl->sdl_type = IFT_ETHER;
511 			sdl->sdl_alen = ifp->if_addrlen;
512 			bcopy((caddr_t)((struct arpcom *)ifp)->ac_enaddr,
513 			      LLADDR(sdl), ifp->if_addrlen);
514 			break;
515 		}
516 }
517 
518 u_char	ether_ipmulticast_min[6] = { 0x01, 0x00, 0x5e, 0x00, 0x00, 0x00 };
519 u_char	ether_ipmulticast_max[6] = { 0x01, 0x00, 0x5e, 0x7f, 0xff, 0xff };
520 /*
521  * Add an Ethernet multicast address or range of addresses to the list for a
522  * given interface.
523  */
524 int
525 ether_addmulti(ifr, ac)
526 	struct ifreq *ifr;
527 	register struct arpcom *ac;
528 {
529 	register struct ether_multi *enm;
530 	struct sockaddr_in *sin;
531 	u_char addrlo[6];
532 	u_char addrhi[6];
533 	int s = splimp();
534 
535 	switch (ifr->ifr_addr.sa_family) {
536 
537 	case AF_UNSPEC:
538 		bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
539 		bcopy(addrlo, addrhi, 6);
540 		break;
541 
542 #ifdef INET
543 	case AF_INET:
544 		sin = (struct sockaddr_in *)&(ifr->ifr_addr);
545 		if (sin->sin_addr.s_addr == INADDR_ANY) {
546 			/*
547 			 * An IP address of INADDR_ANY means listen to all
548 			 * of the Ethernet multicast addresses used for IP.
549 			 * (This is for the sake of IP multicast routers.)
550 			 */
551 			bcopy(ether_ipmulticast_min, addrlo, 6);
552 			bcopy(ether_ipmulticast_max, addrhi, 6);
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 	/*
603 	 * Return ENETRESET to inform the driver that the list has changed
604 	 * and its reception filter should be adjusted accordingly.
605 	 */
606 	return (ENETRESET);
607 }
608 
609 /*
610  * Delete a multicast address record.
611  */
612 int
613 ether_delmulti(ifr, ac)
614 	struct ifreq *ifr;
615 	register struct arpcom *ac;
616 {
617 	register struct ether_multi *enm;
618 	register struct ether_multi **p;
619 	struct sockaddr_in *sin;
620 	u_char addrlo[6];
621 	u_char addrhi[6];
622 	int s = splimp();
623 
624 	switch (ifr->ifr_addr.sa_family) {
625 
626 	case AF_UNSPEC:
627 		bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
628 		bcopy(addrlo, addrhi, 6);
629 		break;
630 
631 #ifdef INET
632 	case AF_INET:
633 		sin = (struct sockaddr_in *)&(ifr->ifr_addr);
634 		if (sin->sin_addr.s_addr == INADDR_ANY) {
635 			/*
636 			 * An IP address of INADDR_ANY means stop listening
637 			 * to the range of Ethernet multicast addresses used
638 			 * for IP.
639 			 */
640 			bcopy(ether_ipmulticast_min, addrlo, 6);
641 			bcopy(ether_ipmulticast_max, addrhi, 6);
642 		}
643 		else {
644 			ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
645 			bcopy(addrlo, addrhi, 6);
646 		}
647 		break;
648 #endif
649 
650 	default:
651 		splx(s);
652 		return (EAFNOSUPPORT);
653 	}
654 
655 	/*
656 	 * Look up the address in our list.
657 	 */
658 	ETHER_LOOKUP_MULTI(addrlo, addrhi, ac, enm);
659 	if (enm == NULL) {
660 		splx(s);
661 		return (ENXIO);
662 	}
663 	if (--enm->enm_refcount != 0) {
664 		/*
665 		 * Still some claims to this record.
666 		 */
667 		splx(s);
668 		return (0);
669 	}
670 	/*
671 	 * No remaining claims to this record; unlink and free it.
672 	 */
673 	for (p = &enm->enm_ac->ac_multiaddrs;
674 	     *p != enm;
675 	     p = &(*p)->enm_next)
676 		continue;
677 	*p = (*p)->enm_next;
678 	free(enm, M_IFMADDR);
679 	ac->ac_multicnt--;
680 	splx(s);
681 	/*
682 	 * Return ENETRESET to inform the driver that the list has changed
683 	 * and its reception filter should be adjusted accordingly.
684 	 */
685 	return (ENETRESET);
686 }
687