xref: /netbsd-src/sys/net/if_ethersubr.c (revision 76dfffe33547c37f8bdd446e3e4ab0f3c16cea4b)
1 /*	$NetBSD: if_ethersubr.c,v 1.21 1996/10/13 02:11:00 christos 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 #include <netinet/in.h>
59 #ifdef INET
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 #define senderr(e) { error = (e); goto bad;}
87 
88 /*
89  * Ethernet output routine.
90  * Encapsulate a packet of type family for the local net.
91  * Assumes that ifp is actually pointer to arpcom structure.
92  */
93 int
94 ether_output(ifp, m0, dst, rt0)
95 	register struct ifnet *ifp;
96 	struct mbuf *m0;
97 	struct sockaddr *dst;
98 	struct rtentry *rt0;
99 {
100 	u_int16_t etype;
101 	int s, error = 0;
102  	u_char edst[6];
103 	register struct mbuf *m = m0;
104 	register struct rtentry *rt;
105 	struct mbuf *mcopy = (struct mbuf *)0;
106 	register struct ether_header *eh;
107 	struct arpcom *ac = (struct arpcom *)ifp;
108 
109 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
110 		senderr(ENETDOWN);
111 	ifp->if_lastchange = time;
112 	if ((rt = rt0) != NULL) {
113 		if ((rt->rt_flags & RTF_UP) == 0) {
114 			if ((rt0 = rt = rtalloc1(dst, 1)) != NULL)
115 				rt->rt_refcnt--;
116 			else
117 				senderr(EHOSTUNREACH);
118 		}
119 		if (rt->rt_flags & RTF_GATEWAY) {
120 			if (rt->rt_gwroute == 0)
121 				goto lookup;
122 			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
123 				rtfree(rt); rt = rt0;
124 			lookup: rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1);
125 				if ((rt = rt->rt_gwroute) == 0)
126 					senderr(EHOSTUNREACH);
127 			}
128 		}
129 		if (rt->rt_flags & RTF_REJECT)
130 			if (rt->rt_rmx.rmx_expire == 0 ||
131 			    time.tv_sec < rt->rt_rmx.rmx_expire)
132 				senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
133 	}
134 	switch (dst->sa_family) {
135 
136 #ifdef INET
137 	case AF_INET:
138 		if (!arpresolve(ac, rt, m, dst, edst))
139 			return (0);	/* if not yet resolved */
140 		/* If broadcasting on a simplex interface, loopback a copy */
141 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
142 			mcopy = m_copy(m, 0, (int)M_COPYALL);
143 		etype = htons(ETHERTYPE_IP);
144 		break;
145 #endif
146 #ifdef NS
147 	case AF_NS:
148 		etype = htons(ETHERTYPE_NS);
149  		bcopy((caddr_t)&(((struct sockaddr_ns *)dst)->sns_addr.x_host),
150 		    (caddr_t)edst, sizeof (edst));
151 		if (!bcmp((caddr_t)edst, (caddr_t)&ns_thishost, sizeof(edst)))
152 			return (looutput(ifp, m, dst, rt));
153 		/* If broadcasting on a simplex interface, loopback a copy */
154 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
155 			mcopy = m_copy(m, 0, (int)M_COPYALL);
156 		break;
157 #endif
158 #ifdef	ISO
159 	case AF_ISO: {
160 		int	snpalen;
161 		struct	llc *l;
162 		register struct sockaddr_dl *sdl;
163 
164 		if (rt && (sdl = (struct sockaddr_dl *)rt->rt_gateway) &&
165 		    sdl->sdl_family == AF_LINK && sdl->sdl_alen > 0) {
166 			bcopy(LLADDR(sdl), (caddr_t)edst, sizeof(edst));
167 		} else {
168 			error = iso_snparesolve(ifp, (struct sockaddr_iso *)dst,
169 						(char *)edst, &snpalen);
170 			if (error)
171 				goto bad; /* Not Resolved */
172 		}
173 		/* If broadcasting on a simplex interface, loopback a copy */
174 		if (*edst & 1)
175 			m->m_flags |= (M_BCAST|M_MCAST);
176 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX) &&
177 		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
178 			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
179 			if (mcopy) {
180 				eh = mtod(mcopy, struct ether_header *);
181 				bcopy((caddr_t)edst,
182 				      (caddr_t)eh->ether_dhost, sizeof (edst));
183 				bcopy((caddr_t)ac->ac_enaddr,
184 				      (caddr_t)eh->ether_shost, sizeof (edst));
185 			}
186 		}
187 		M_PREPEND(m, 3, M_DONTWAIT);
188 		if (m == NULL)
189 			return (0);
190 		etype = htons(m->m_pkthdr.len);
191 		l = mtod(m, struct llc *);
192 		l->llc_dsap = l->llc_ssap = LLC_ISO_LSAP;
193 		l->llc_control = LLC_UI;
194 #ifdef ARGO_DEBUG
195 		if (argo_debug[D_ETHER]) {
196 			int i;
197 			printf("unoutput: sending pkt to: ");
198 			for (i=0; i<6; i++)
199 				printf("%x ", edst[i] & 0xff);
200 			printf("\n");
201 		}
202 #endif
203 		} break;
204 #endif /* ISO */
205 #ifdef	LLC
206 /*	case AF_NSAP: */
207 	case AF_CCITT: {
208 		register struct sockaddr_dl *sdl =
209 			(struct sockaddr_dl *) rt -> rt_gateway;
210 
211 		if (sdl && sdl->sdl_family == AF_LINK
212 		    && sdl->sdl_alen > 0) {
213 			bcopy(LLADDR(sdl), (char *)edst,
214 				sizeof(edst));
215 		} else goto bad; /* Not a link interface ? Funny ... */
216 		if ((ifp->if_flags & IFF_SIMPLEX) && (*edst & 1) &&
217 		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
218 			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
219 			if (mcopy) {
220 				eh = mtod(mcopy, struct ether_header *);
221 				bcopy((caddr_t)edst,
222 				      (caddr_t)eh->ether_dhost, sizeof (edst));
223 				bcopy((caddr_t)ac->ac_enaddr,
224 				      (caddr_t)eh->ether_shost, sizeof (edst));
225 			}
226 		}
227 		etype = htons(m->m_pkthdr.len);
228 #ifdef LLC_DEBUG
229 		{
230 			int i;
231 			register struct llc *l = mtod(m, struct llc *);
232 
233 			printf("ether_output: sending LLC2 pkt to: ");
234 			for (i=0; i<6; i++)
235 				printf("%x ", edst[i] & 0xff);
236 			printf(" len 0x%x dsap 0x%x ssap 0x%x control 0x%x\n",
237 			    m->m_pkthdr.len, l->llc_dsap & 0xff, l->llc_ssap &0xff,
238 			    l->llc_control & 0xff);
239 
240 		}
241 #endif /* LLC_DEBUG */
242 		} break;
243 #endif /* LLC */
244 
245 	case AF_UNSPEC:
246 		eh = (struct ether_header *)dst->sa_data;
247  		bcopy((caddr_t)eh->ether_dhost, (caddr_t)edst, sizeof (edst));
248 		/* AF_UNSPEC doesn't swap the byte order of the ether_type. */
249 		etype = eh->ether_type;
250 		break;
251 
252 	default:
253 		printf("%s: can't handle af%d\n", ifp->if_xname,
254 			dst->sa_family);
255 		senderr(EAFNOSUPPORT);
256 	}
257 
258 	if (mcopy)
259 		(void) looutput(ifp, mcopy, dst, rt);
260 
261 	/*
262 	 * Add local net header.  If no space in first mbuf,
263 	 * allocate another.
264 	 */
265 	M_PREPEND(m, sizeof (struct ether_header), M_DONTWAIT);
266 	if (m == 0)
267 		senderr(ENOBUFS);
268 	eh = mtod(m, struct ether_header *);
269 	bcopy((caddr_t)&etype,(caddr_t)&eh->ether_type,
270 		sizeof(eh->ether_type));
271  	bcopy((caddr_t)edst, (caddr_t)eh->ether_dhost, sizeof (edst));
272  	bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost,
273 	    sizeof(eh->ether_shost));
274 	s = splimp();
275 	/*
276 	 * Queue message on interface, and start output if interface
277 	 * not yet active.
278 	 */
279 	if (IF_QFULL(&ifp->if_snd)) {
280 		IF_DROP(&ifp->if_snd);
281 		splx(s);
282 		senderr(ENOBUFS);
283 	}
284 	ifp->if_obytes += m->m_pkthdr.len;
285 	IF_ENQUEUE(&ifp->if_snd, m);
286 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
287 		(*ifp->if_start)(ifp);
288 	splx(s);
289 	if (m->m_flags & M_MCAST)
290 		ifp->if_omcasts++;
291 	return (error);
292 
293 bad:
294 	if (m)
295 		m_freem(m);
296 	return (error);
297 }
298 
299 /*
300  * Process a received Ethernet packet;
301  * the packet is in the mbuf chain m without
302  * the ether header, which is provided separately.
303  */
304 void
305 ether_input(ifp, eh, m)
306 	struct ifnet *ifp;
307 	register struct ether_header *eh;
308 	struct mbuf *m;
309 {
310 	register struct ifqueue *inq;
311 	u_int16_t etype;
312 	int s;
313 #if defined (ISO) || defined (LLC)
314 	register struct llc *l;
315 	struct arpcom *ac = (struct arpcom *)ifp;
316 #endif
317 
318 	if ((ifp->if_flags & IFF_UP) == 0) {
319 		m_freem(m);
320 		return;
321 	}
322 	ifp->if_lastchange = time;
323 	ifp->if_ibytes += m->m_pkthdr.len + sizeof (*eh);
324 	if (eh->ether_dhost[0] & 1) {
325 		if (bcmp((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
326 		    sizeof(etherbroadcastaddr)) == 0)
327 			m->m_flags |= M_BCAST;
328 		else
329 			m->m_flags |= M_MCAST;
330 	}
331 	if (m->m_flags & (M_BCAST|M_MCAST))
332 		ifp->if_imcasts++;
333 
334 	etype = ntohs(eh->ether_type);
335 	switch (etype) {
336 #ifdef INET
337 	case ETHERTYPE_IP:
338 		schednetisr(NETISR_IP);
339 		inq = &ipintrq;
340 		break;
341 
342 	case ETHERTYPE_ARP:
343 		schednetisr(NETISR_ARP);
344 		inq = &arpintrq;
345 		break;
346 
347 	case ETHERTYPE_REVARP:
348 		revarpinput(m);	/* XXX queue? */
349 		return;
350 #endif
351 #ifdef NS
352 	case ETHERTYPE_NS:
353 		schednetisr(NETISR_NS);
354 		inq = &nsintrq;
355 		break;
356 
357 #endif
358 	default:
359 #if defined (ISO) || defined (LLC)
360 		if (etype > ETHERMTU)
361 			goto dropanyway;
362 		l = mtod(m, struct llc *);
363 		switch (l->llc_dsap) {
364 #ifdef	ISO
365 		case LLC_ISO_LSAP:
366 			switch (l->llc_control) {
367 			case LLC_UI:
368 				/* LLC_UI_P forbidden in class 1 service */
369 				if ((l->llc_dsap == LLC_ISO_LSAP) &&
370 				    (l->llc_ssap == LLC_ISO_LSAP)) {
371 					/* LSAP for ISO */
372 					if (m->m_pkthdr.len > etype)
373 						m_adj(m, etype - m->m_pkthdr.len);
374 					m->m_data += 3;		/* XXX */
375 					m->m_len -= 3;		/* XXX */
376 					m->m_pkthdr.len -= 3;	/* XXX */
377 					M_PREPEND(m, sizeof *eh, M_DONTWAIT);
378 					if (m == 0)
379 						return;
380 					*mtod(m, struct ether_header *) = *eh;
381 #ifdef ARGO_DEBUG
382 					if (argo_debug[D_ETHER])
383 						printf("clnp packet");
384 #endif
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 > etype)
435 				m_adj(m, etype - 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 = etype;
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 	ifp->if_output = ether_output;
508 	for (ifa = ifp->if_addrlist.tqh_first; ifa != 0;
509 	    ifa = ifa->ifa_list.tqe_next)
510 		if ((sdl = (struct sockaddr_dl *)ifa->ifa_addr) &&
511 		    sdl->sdl_family == AF_LINK) {
512 			sdl->sdl_type = IFT_ETHER;
513 			sdl->sdl_alen = ifp->if_addrlen;
514 			bcopy((caddr_t)((struct arpcom *)ifp)->ac_enaddr,
515 			      LLADDR(sdl), ifp->if_addrlen);
516 			break;
517 		}
518 	LIST_INIT(&((struct arpcom *)ifp)->ac_multiaddrs);
519 }
520 
521 u_char	ether_ipmulticast_min[6] = { 0x01, 0x00, 0x5e, 0x00, 0x00, 0x00 };
522 u_char	ether_ipmulticast_max[6] = { 0x01, 0x00, 0x5e, 0x7f, 0xff, 0xff };
523 /*
524  * Add an Ethernet multicast address or range of addresses to the list for a
525  * given interface.
526  */
527 int
528 ether_addmulti(ifr, ac)
529 	struct ifreq *ifr;
530 	register struct arpcom *ac;
531 {
532 	register struct ether_multi *enm;
533 	struct sockaddr_in *sin;
534 	u_char addrlo[6];
535 	u_char addrhi[6];
536 	int s = splimp();
537 
538 	switch (ifr->ifr_addr.sa_family) {
539 
540 	case AF_UNSPEC:
541 		bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
542 		bcopy(addrlo, addrhi, 6);
543 		break;
544 
545 #ifdef INET
546 	case AF_INET:
547 		sin = (struct sockaddr_in *)&(ifr->ifr_addr);
548 		if (sin->sin_addr.s_addr == INADDR_ANY) {
549 			/*
550 			 * An IP address of INADDR_ANY means listen to all
551 			 * of the Ethernet multicast addresses used for IP.
552 			 * (This is for the sake of IP multicast routers.)
553 			 */
554 			bcopy(ether_ipmulticast_min, addrlo, 6);
555 			bcopy(ether_ipmulticast_max, addrhi, 6);
556 		}
557 		else {
558 			ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
559 			bcopy(addrlo, addrhi, 6);
560 		}
561 		break;
562 #endif
563 
564 	default:
565 		splx(s);
566 		return (EAFNOSUPPORT);
567 	}
568 
569 	/*
570 	 * Verify that we have valid Ethernet multicast addresses.
571 	 */
572 	if ((addrlo[0] & 0x01) != 1 || (addrhi[0] & 0x01) != 1) {
573 		splx(s);
574 		return (EINVAL);
575 	}
576 	/*
577 	 * See if the address range is already in the list.
578 	 */
579 	ETHER_LOOKUP_MULTI(addrlo, addrhi, ac, enm);
580 	if (enm != NULL) {
581 		/*
582 		 * Found it; just increment the reference count.
583 		 */
584 		++enm->enm_refcount;
585 		splx(s);
586 		return (0);
587 	}
588 	/*
589 	 * New address or range; malloc a new multicast record
590 	 * and link it into the interface's multicast list.
591 	 */
592 	enm = (struct ether_multi *)malloc(sizeof(*enm), M_IFMADDR, M_NOWAIT);
593 	if (enm == NULL) {
594 		splx(s);
595 		return (ENOBUFS);
596 	}
597 	bcopy(addrlo, enm->enm_addrlo, 6);
598 	bcopy(addrhi, enm->enm_addrhi, 6);
599 	enm->enm_ac = ac;
600 	enm->enm_refcount = 1;
601 	LIST_INSERT_HEAD(&ac->ac_multiaddrs, enm, enm_list);
602 	ac->ac_multicnt++;
603 	splx(s);
604 	/*
605 	 * Return ENETRESET to inform the driver that the list has changed
606 	 * and its reception filter should be adjusted accordingly.
607 	 */
608 	return (ENETRESET);
609 }
610 
611 /*
612  * Delete a multicast address record.
613  */
614 int
615 ether_delmulti(ifr, ac)
616 	struct ifreq *ifr;
617 	register struct arpcom *ac;
618 {
619 	register struct ether_multi *enm;
620 	struct sockaddr_in *sin;
621 	u_char addrlo[6];
622 	u_char addrhi[6];
623 	int s = splimp();
624 
625 	switch (ifr->ifr_addr.sa_family) {
626 
627 	case AF_UNSPEC:
628 		bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
629 		bcopy(addrlo, addrhi, 6);
630 		break;
631 
632 #ifdef INET
633 	case AF_INET:
634 		sin = (struct sockaddr_in *)&(ifr->ifr_addr);
635 		if (sin->sin_addr.s_addr == INADDR_ANY) {
636 			/*
637 			 * An IP address of INADDR_ANY means stop listening
638 			 * to the range of Ethernet multicast addresses used
639 			 * for IP.
640 			 */
641 			bcopy(ether_ipmulticast_min, addrlo, 6);
642 			bcopy(ether_ipmulticast_max, addrhi, 6);
643 		}
644 		else {
645 			ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
646 			bcopy(addrlo, addrhi, 6);
647 		}
648 		break;
649 #endif
650 
651 	default:
652 		splx(s);
653 		return (EAFNOSUPPORT);
654 	}
655 
656 	/*
657 	 * Look up the address in our list.
658 	 */
659 	ETHER_LOOKUP_MULTI(addrlo, addrhi, ac, enm);
660 	if (enm == NULL) {
661 		splx(s);
662 		return (ENXIO);
663 	}
664 	if (--enm->enm_refcount != 0) {
665 		/*
666 		 * Still some claims to this record.
667 		 */
668 		splx(s);
669 		return (0);
670 	}
671 	/*
672 	 * No remaining claims to this record; unlink and free it.
673 	 */
674 	LIST_REMOVE(enm, enm_list);
675 	free(enm, M_IFMADDR);
676 	ac->ac_multicnt--;
677 	splx(s);
678 	/*
679 	 * Return ENETRESET to inform the driver that the list has changed
680 	 * and its reception filter should be adjusted accordingly.
681 	 */
682 	return (ENETRESET);
683 }
684