xref: /netbsd-src/sys/net/if_ethersubr.c (revision ce0bb6e8d2e560ecacbe865a848624f94498063b)
1 /*	$NetBSD: if_ethersubr.c,v 1.12 1995/04/07 22:19:29 mycroft 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 #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  * Use trailer local net encapsulation if enough data in first
92  * packet leaves a multiple of 512 bytes of data in remainder.
93  * Assumes that ifp is actually pointer to arpcom structure.
94  */
95 int
96 ether_output(ifp, m0, dst, rt0)
97 	register struct ifnet *ifp;
98 	struct mbuf *m0;
99 	struct sockaddr *dst;
100 	struct rtentry *rt0;
101 {
102 	u_int16_t etype;
103 	int s, error = 0;
104  	u_char edst[6];
105 	register struct mbuf *m = m0;
106 	register struct rtentry *rt;
107 	struct mbuf *mcopy = (struct mbuf *)0;
108 	register struct ether_header *eh;
109 	int off, len = m->m_pkthdr.len;
110 	struct arpcom *ac = (struct arpcom *)ifp;
111 
112 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
113 		senderr(ENETDOWN);
114 	ifp->if_lastchange = time;
115 	if (rt = rt0) {
116 		if ((rt->rt_flags & RTF_UP) == 0) {
117 			if (rt0 = rt = rtalloc1(dst, 1))
118 				rt->rt_refcnt--;
119 			else
120 				senderr(EHOSTUNREACH);
121 		}
122 		if (rt->rt_flags & RTF_GATEWAY) {
123 			if (rt->rt_gwroute == 0)
124 				goto lookup;
125 			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
126 				rtfree(rt); rt = rt0;
127 			lookup: rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1);
128 				if ((rt = rt->rt_gwroute) == 0)
129 					senderr(EHOSTUNREACH);
130 			}
131 		}
132 		if (rt->rt_flags & RTF_REJECT)
133 			if (rt->rt_rmx.rmx_expire == 0 ||
134 			    time.tv_sec < rt->rt_rmx.rmx_expire)
135 				senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
136 	}
137 	switch (dst->sa_family) {
138 
139 #ifdef INET
140 	case AF_INET:
141 		if (!arpresolve(ac, rt, m, dst, edst))
142 			return (0);	/* if not yet resolved */
143 		/* If broadcasting on a simplex interface, loopback a copy */
144 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
145 			mcopy = m_copy(m, 0, (int)M_COPYALL);
146 		off = m->m_pkthdr.len - m->m_len;
147 		etype = ETHERTYPE_IP;
148 		break;
149 #endif
150 #ifdef NS
151 	case AF_NS:
152 		etype = ETHERTYPE_NS;
153  		bcopy((caddr_t)&(((struct sockaddr_ns *)dst)->sns_addr.x_host),
154 		    (caddr_t)edst, sizeof (edst));
155 		if (!bcmp((caddr_t)edst, (caddr_t)&ns_thishost, sizeof(edst)))
156 			return (looutput(ifp, m, dst, rt));
157 		/* If broadcasting on a simplex interface, loopback a copy */
158 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
159 			mcopy = m_copy(m, 0, (int)M_COPYALL);
160 		break;
161 #endif
162 #ifdef	ISO
163 	case AF_ISO: {
164 		int	snpalen;
165 		struct	llc *l;
166 		register struct sockaddr_dl *sdl;
167 
168 		if (rt && (sdl = (struct sockaddr_dl *)rt->rt_gateway) &&
169 		    sdl->sdl_family == AF_LINK && sdl->sdl_alen > 0) {
170 			bcopy(LLADDR(sdl), (caddr_t)edst, sizeof(edst));
171 		} else if (error =
172 			    iso_snparesolve(ifp, (struct sockaddr_iso *)dst,
173 					    (char *)edst, &snpalen))
174 			goto bad; /* Not Resolved */
175 		/* If broadcasting on a simplex interface, loopback a copy */
176 		if (*edst & 1)
177 			m->m_flags |= (M_BCAST|M_MCAST);
178 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX) &&
179 		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
180 			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
181 			if (mcopy) {
182 				eh = mtod(mcopy, struct ether_header *);
183 				bcopy((caddr_t)edst,
184 				      (caddr_t)eh->ether_dhost, sizeof (edst));
185 				bcopy((caddr_t)ac->ac_enaddr,
186 				      (caddr_t)eh->ether_shost, sizeof (edst));
187 			}
188 		}
189 		M_PREPEND(m, 3, M_DONTWAIT);
190 		if (m == NULL)
191 			return (0);
192 		etype = m->m_pkthdr.len;
193 		l = mtod(m, struct llc *);
194 		l->llc_dsap = l->llc_ssap = LLC_ISO_LSAP;
195 		l->llc_control = LLC_UI;
196 		len += 3;
197 		IFDEBUG(D_ETHER)
198 			int i;
199 			printf("unoutput: sending pkt to: ");
200 			for (i=0; i<6; i++)
201 				printf("%x ", edst[i] & 0xff);
202 			printf("\n");
203 		ENDDEBUG
204 		} break;
205 #endif /* ISO */
206 #ifdef	LLC
207 /*	case AF_NSAP: */
208 	case AF_CCITT: {
209 		register struct sockaddr_dl *sdl =
210 			(struct sockaddr_dl *) rt -> rt_gateway;
211 
212 		if (sdl && sdl->sdl_family == AF_LINK
213 		    && sdl->sdl_alen > 0) {
214 			bcopy(LLADDR(sdl), (char *)edst,
215 				sizeof(edst));
216 		} else goto bad; /* Not a link interface ? Funny ... */
217 		if ((ifp->if_flags & IFF_SIMPLEX) && (*edst & 1) &&
218 		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
219 			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
220 			if (mcopy) {
221 				eh = mtod(mcopy, struct ether_header *);
222 				bcopy((caddr_t)edst,
223 				      (caddr_t)eh->ether_dhost, sizeof (edst));
224 				bcopy((caddr_t)ac->ac_enaddr,
225 				      (caddr_t)eh->ether_shost, sizeof (edst));
226 			}
227 		}
228 		etype = m->m_pkthdr.len;
229 #ifdef LLC_DEBUG
230 		{
231 			int i;
232 			register struct llc *l = mtod(m, struct llc *);
233 
234 			printf("ether_output: sending LLC2 pkt to: ");
235 			for (i=0; i<6; i++)
236 				printf("%x ", edst[i] & 0xff);
237 			printf(" len 0x%x dsap 0x%x ssap 0x%x control 0x%x\n",
238 			       etype & 0xff, l->llc_dsap & 0xff, l->llc_ssap &0xff,
239 			       l->llc_control & 0xff);
240 
241 		}
242 #endif /* LLC_DEBUG */
243 		} break;
244 #endif /* LLC */
245 
246 	case AF_UNSPEC:
247 		eh = (struct ether_header *)dst->sa_data;
248  		bcopy((caddr_t)eh->ether_dhost, (caddr_t)edst, sizeof (edst));
249 		/* AF_UNSPEC doesn't swap the byte order of the ether_type. */
250 		etype = ntohs(eh->ether_type);
251 		break;
252 
253 	default:
254 		printf("%s%d: can't handle af%d\n", ifp->if_name, ifp->if_unit,
255 			dst->sa_family);
256 		senderr(EAFNOSUPPORT);
257 	}
258 
259 
260 	if (mcopy)
261 		(void) looutput(ifp, mcopy, dst, rt);
262 	/*
263 	 * Add local net header.  If no space in first mbuf,
264 	 * allocate another.
265 	 */
266 	M_PREPEND(m, sizeof (struct ether_header), M_DONTWAIT);
267 	if (m == 0)
268 		senderr(ENOBUFS);
269 	eh = mtod(m, struct ether_header *);
270 	etype = htons(etype);
271 	bcopy((caddr_t)&etype,(caddr_t)&eh->ether_type,
272 		sizeof(eh->ether_type));
273  	bcopy((caddr_t)edst, (caddr_t)eh->ether_dhost, sizeof (edst));
274  	bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost,
275 	    sizeof(eh->ether_shost));
276 	s = splimp();
277 	/*
278 	 * Queue message on interface, and start output if interface
279 	 * not yet active.
280 	 */
281 	if (IF_QFULL(&ifp->if_snd)) {
282 		IF_DROP(&ifp->if_snd);
283 		splx(s);
284 		senderr(ENOBUFS);
285 	}
286 	IF_ENQUEUE(&ifp->if_snd, m);
287 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
288 		(*ifp->if_start)(ifp);
289 	splx(s);
290 	ifp->if_obytes += len + sizeof (struct ether_header);
291 	if (m->m_flags & M_MCAST)
292 		ifp->if_omcasts++;
293 	return (error);
294 
295 bad:
296 	if (m)
297 		m_freem(m);
298 	return (error);
299 }
300 
301 /*
302  * Process a received Ethernet packet;
303  * the packet is in the mbuf chain m without
304  * the ether header, which is provided separately.
305  */
306 void
307 ether_input(ifp, eh, m)
308 	struct ifnet *ifp;
309 	register struct ether_header *eh;
310 	struct mbuf *m;
311 {
312 	register struct ifqueue *inq;
313 	register struct llc *l;
314 	u_int16_t etype;
315 	struct arpcom *ac = (struct arpcom *)ifp;
316 	int s;
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 					IFDEBUG(D_ETHER)
382 						printf("clnp packet");
383 					ENDDEBUG
384 					schednetisr(NETISR_ISO);
385 					inq = &clnlintrq;
386 					break;
387 				}
388 				goto dropanyway;
389 
390 			case LLC_XID:
391 			case LLC_XID_P:
392 				if(m->m_len < 6)
393 					goto dropanyway;
394 				l->llc_window = 0;
395 				l->llc_fid = 9;
396 				l->llc_class = 1;
397 				l->llc_dsap = l->llc_ssap = 0;
398 				/* Fall through to */
399 			case LLC_TEST:
400 			case LLC_TEST_P:
401 			{
402 				struct sockaddr sa;
403 				register struct ether_header *eh2;
404 				int i;
405 				u_char c = l->llc_dsap;
406 
407 				l->llc_dsap = l->llc_ssap;
408 				l->llc_ssap = c;
409 				if (m->m_flags & (M_BCAST | M_MCAST))
410 					bcopy((caddr_t)ac->ac_enaddr,
411 					      (caddr_t)eh->ether_dhost, 6);
412 				sa.sa_family = AF_UNSPEC;
413 				sa.sa_len = sizeof(sa);
414 				eh2 = (struct ether_header *)sa.sa_data;
415 				for (i = 0; i < 6; i++) {
416 					eh2->ether_shost[i] = c = eh->ether_dhost[i];
417 					eh2->ether_dhost[i] =
418 						eh->ether_dhost[i] = eh->ether_shost[i];
419 					eh->ether_shost[i] = c;
420 				}
421 				ifp->if_output(ifp, m, &sa, NULL);
422 				return;
423 			}
424 			default:
425 				m_freem(m);
426 				return;
427 			}
428 			break;
429 #endif /* ISO */
430 #ifdef LLC
431 		case LLC_X25_LSAP:
432 		{
433 			if (m->m_pkthdr.len > etype)
434 				m_adj(m, etype - m->m_pkthdr.len);
435 			M_PREPEND(m, sizeof(struct sdl_hdr) , M_DONTWAIT);
436 			if (m == 0)
437 				return;
438 			if ( !sdl_sethdrif(ifp, eh->ether_shost, LLC_X25_LSAP,
439 					    eh->ether_dhost, LLC_X25_LSAP, 6,
440 					    mtod(m, struct sdl_hdr *)))
441 				panic("ETHER cons addr failure");
442 			mtod(m, struct sdl_hdr *)->sdlhdr_len = etype;
443 #ifdef LLC_DEBUG
444 				printf("llc packet\n");
445 #endif /* LLC_DEBUG */
446 			schednetisr(NETISR_CCITT);
447 			inq = &llcintrq;
448 			break;
449 		}
450 #endif /* LLC */
451 		dropanyway:
452 		default:
453 			m_freem(m);
454 			return;
455 		}
456 #else /* ISO || LLC */
457 	    m_freem(m);
458 	    return;
459 #endif /* ISO || LLC */
460 	}
461 
462 	s = splimp();
463 	if (IF_QFULL(inq)) {
464 		IF_DROP(inq);
465 		m_freem(m);
466 	} else
467 		IF_ENQUEUE(inq, m);
468 	splx(s);
469 }
470 
471 /*
472  * Convert Ethernet address to printable (loggable) representation.
473  */
474 static char digits[] = "0123456789abcdef";
475 char *
476 ether_sprintf(ap)
477 	register u_char *ap;
478 {
479 	register i;
480 	static char etherbuf[18];
481 	register char *cp = etherbuf;
482 
483 	for (i = 0; i < 6; i++) {
484 		*cp++ = digits[*ap >> 4];
485 		*cp++ = digits[*ap++ & 0xf];
486 		*cp++ = ':';
487 	}
488 	*--cp = 0;
489 	return (etherbuf);
490 }
491 
492 /*
493  * Perform common duties while attaching to interface list
494  */
495 void
496 ether_ifattach(ifp)
497 	register struct ifnet *ifp;
498 {
499 	register struct ifaddr *ifa;
500 	register struct sockaddr_dl *sdl;
501 
502 	ifp->if_type = IFT_ETHER;
503 	ifp->if_addrlen = 6;
504 	ifp->if_hdrlen = 14;
505 	ifp->if_mtu = ETHERMTU;
506 	ifp->if_output = ether_output;
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