xref: /freebsd/sys/net/if_ethersubr.c (revision 8e6b01171e30297084bb0b4457c4183c2746aacc)
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 1.9 1995/06/11 19:31:39 rgrimes 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 
48 #include <machine/cpu.h>
49 
50 #include <net/if.h>
51 #include <net/netisr.h>
52 #include <net/route.h>
53 #include <net/if_llc.h>
54 #include <net/if_dl.h>
55 #include <net/if_types.h>
56 
57 #ifdef INET
58 #include <netinet/in.h>
59 #include <netinet/in_var.h>
60 #endif
61 #include <netinet/if_ether.h>
62 
63 #ifdef IPX
64 #include <netipx/ipx.h>
65 #include <netipx/ipx_if.h>
66 #endif
67 
68 #ifdef NS
69 #include <netns/ns.h>
70 #include <netns/ns_if.h>
71 #endif
72 
73 #ifdef ISO
74 #include <netiso/argo_debug.h>
75 #include <netiso/iso.h>
76 #include <netiso/iso_var.h>
77 #include <netiso/iso_snpac.h>
78 #endif
79 
80 #ifdef LLC
81 #include <netccitt/dll.h>
82 #include <netccitt/llc_var.h>
83 #endif
84 
85 #if defined(LLC) && defined(CCITT)
86 extern struct ifqueue pkintrq;
87 #endif
88 
89 u_char	etherbroadcastaddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
90 #define senderr(e) { error = (e); goto bad;}
91 
92 /*
93  * Ethernet output routine.
94  * Encapsulate a packet of type family for the local net.
95  * Use trailer local net encapsulation if enough data in first
96  * packet leaves a multiple of 512 bytes of data in remainder.
97  * Assumes that ifp is actually pointer to arpcom structure.
98  */
99 int
100 ether_output(ifp, m0, dst, rt0)
101 	register struct ifnet *ifp;
102 	struct mbuf *m0;
103 	struct sockaddr *dst;
104 	struct rtentry *rt0;
105 {
106 	short type;
107 	int s, error = 0;
108  	u_char edst[6];
109 	register struct mbuf *m = m0;
110 	register struct rtentry *rt;
111 	struct mbuf *mcopy = (struct mbuf *)0;
112 	register struct ether_header *eh;
113 	int off, len = m->m_pkthdr.len;
114 	struct arpcom *ac = (struct arpcom *)ifp;
115 
116 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
117 		senderr(ENETDOWN);
118 	ifp->if_lastchange = time;
119 	if (rt = rt0) {
120 		if ((rt->rt_flags & RTF_UP) == 0) {
121 			if (rt0 = rt = rtalloc1(dst, 1, 0UL))
122 				rt->rt_refcnt--;
123 			else
124 				senderr(EHOSTUNREACH);
125 		}
126 		if (rt->rt_flags & RTF_GATEWAY) {
127 			if (rt->rt_gwroute == 0)
128 				goto lookup;
129 			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
130 				rtfree(rt); rt = rt0;
131 			lookup: rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1,
132 							  0UL);
133 				if ((rt = rt->rt_gwroute) == 0)
134 					senderr(EHOSTUNREACH);
135 			}
136 		}
137 		if (rt->rt_flags & RTF_REJECT)
138 			if (rt->rt_rmx.rmx_expire == 0 ||
139 			    time.tv_sec < rt->rt_rmx.rmx_expire)
140 				senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
141 	}
142 	switch (dst->sa_family) {
143 
144 #ifdef INET
145 	case AF_INET:
146 		if (!arpresolve(ac, rt, m, dst, edst, rt0))
147 			return (0);	/* if not yet resolved */
148 		/* If broadcasting on a simplex interface, loopback a copy */
149 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
150 			mcopy = m_copy(m, 0, (int)M_COPYALL);
151 		off = m->m_pkthdr.len - m->m_len;
152 		type = ETHERTYPE_IP;
153 		break;
154 #endif
155 #ifdef IPX
156 	case AF_IPX:
157 		type = ETHERTYPE_IPX;
158  		bcopy((caddr_t)&(((struct sockaddr_ipx *)dst)->sipx_addr.x_host),
159 		    (caddr_t)edst, sizeof (edst));
160 		if (!bcmp((caddr_t)edst, (caddr_t)&ipx_thishost, sizeof(edst)))
161 			return (looutput(ifp, m, dst, rt));
162 		/* If broadcasting on a simplex interface, loopback a copy */
163 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
164 			mcopy = m_copy(m, 0, (int)M_COPYALL);
165 		break;
166 #endif
167 #ifdef NS
168 	case AF_NS:
169 		type = ETHERTYPE_NS;
170  		bcopy((caddr_t)&(((struct sockaddr_ns *)dst)->sns_addr.x_host),
171 		    (caddr_t)edst, sizeof (edst));
172 		if (!bcmp((caddr_t)edst, (caddr_t)&ns_thishost, sizeof(edst)))
173 			return (looutput(ifp, m, dst, rt));
174 		/* If broadcasting on a simplex interface, loopback a copy */
175 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
176 			mcopy = m_copy(m, 0, (int)M_COPYALL);
177 		break;
178 #endif
179 #ifdef	ISO
180 	case AF_ISO: {
181 		int	snpalen;
182 		struct	llc *l;
183 		register struct sockaddr_dl *sdl;
184 
185 		if (rt && (sdl = (struct sockaddr_dl *)rt->rt_gateway) &&
186 		    sdl->sdl_family == AF_LINK && sdl->sdl_alen > 0) {
187 			bcopy(LLADDR(sdl), (caddr_t)edst, sizeof(edst));
188 		} else if (error =
189 			    iso_snparesolve(ifp, (struct sockaddr_iso *)dst,
190 					    (char *)edst, &snpalen))
191 			goto bad; /* Not Resolved */
192 		/* If broadcasting on a simplex interface, loopback a copy */
193 		if (*edst & 1)
194 			m->m_flags |= (M_BCAST|M_MCAST);
195 		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX) &&
196 		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
197 			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
198 			if (mcopy) {
199 				eh = mtod(mcopy, struct ether_header *);
200 				bcopy((caddr_t)edst,
201 				      (caddr_t)eh->ether_dhost, sizeof (edst));
202 				bcopy((caddr_t)ac->ac_enaddr,
203 				      (caddr_t)eh->ether_shost, sizeof (edst));
204 			}
205 		}
206 		M_PREPEND(m, 3, M_DONTWAIT);
207 		if (m == NULL)
208 			return (0);
209 		type = m->m_pkthdr.len;
210 		l = mtod(m, struct llc *);
211 		l->llc_dsap = l->llc_ssap = LLC_ISO_LSAP;
212 		l->llc_control = LLC_UI;
213 		len += 3;
214 		IFDEBUG(D_ETHER)
215 			int i;
216 			printf("unoutput: sending pkt to: ");
217 			for (i=0; i<6; i++)
218 				printf("%x ", edst[i] & 0xff);
219 			printf("\n");
220 		ENDDEBUG
221 		} break;
222 #endif /* ISO */
223 #ifdef	LLC
224 /*	case AF_NSAP: */
225 	case AF_CCITT: {
226 		register struct sockaddr_dl *sdl =
227 			(struct sockaddr_dl *) rt -> rt_gateway;
228 
229 		if (sdl && sdl->sdl_family == AF_LINK
230 		    && sdl->sdl_alen > 0) {
231 			bcopy(LLADDR(sdl), (char *)edst,
232 				sizeof(edst));
233 		} else goto bad; /* Not a link interface ? Funny ... */
234 		if ((ifp->if_flags & IFF_SIMPLEX) && (*edst & 1) &&
235 		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
236 			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
237 			if (mcopy) {
238 				eh = mtod(mcopy, struct ether_header *);
239 				bcopy((caddr_t)edst,
240 				      (caddr_t)eh->ether_dhost, sizeof (edst));
241 				bcopy((caddr_t)ac->ac_enaddr,
242 				      (caddr_t)eh->ether_shost, sizeof (edst));
243 			}
244 		}
245 		type = m->m_pkthdr.len;
246 #ifdef LLC_DEBUG
247 		{
248 			int i;
249 			register struct llc *l = mtod(m, struct llc *);
250 
251 			printf("ether_output: sending LLC2 pkt to: ");
252 			for (i=0; i<6; i++)
253 				printf("%x ", edst[i] & 0xff);
254 			printf(" len 0x%x dsap 0x%x ssap 0x%x control 0x%x\n",
255 			       type & 0xff, l->llc_dsap & 0xff, l->llc_ssap &0xff,
256 			       l->llc_control & 0xff);
257 
258 		}
259 #endif /* LLC_DEBUG */
260 		} break;
261 #endif /* LLC */
262 
263 	case AF_UNSPEC:
264 		eh = (struct ether_header *)dst->sa_data;
265  		(void)memcpy(edst, eh->ether_dhost, sizeof (edst));
266 		type = eh->ether_type;
267 		break;
268 
269 	default:
270 		printf("%s%d: can't handle af%d\n", ifp->if_name, ifp->if_unit,
271 			dst->sa_family);
272 		senderr(EAFNOSUPPORT);
273 	}
274 
275 
276 	if (mcopy)
277 		(void) looutput(ifp, mcopy, dst, rt);
278 	/*
279 	 * Add local net header.  If no space in first mbuf,
280 	 * allocate another.
281 	 */
282 	M_PREPEND(m, sizeof (struct ether_header), M_DONTWAIT);
283 	if (m == 0)
284 		senderr(ENOBUFS);
285 	eh = mtod(m, struct ether_header *);
286 	type = htons((u_short)type);
287 	(void)memcpy(&eh->ether_type, &type,
288 		sizeof(eh->ether_type));
289  	(void)memcpy(eh->ether_dhost, edst, sizeof (edst));
290  	(void)memcpy(eh->ether_shost, ac->ac_enaddr,
291 	    sizeof(eh->ether_shost));
292 	s = splimp();
293 	/*
294 	 * Queue message on interface, and start output if interface
295 	 * not yet active.
296 	 */
297 	if (IF_QFULL(&ifp->if_snd)) {
298 		IF_DROP(&ifp->if_snd);
299 		splx(s);
300 		senderr(ENOBUFS);
301 	}
302 	IF_ENQUEUE(&ifp->if_snd, m);
303 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
304 		(*ifp->if_start)(ifp);
305 	splx(s);
306 	ifp->if_obytes += len + sizeof (struct ether_header);
307 	if (m->m_flags & M_MCAST)
308 		ifp->if_omcasts++;
309 	return (error);
310 
311 bad:
312 	if (m)
313 		m_freem(m);
314 	return (error);
315 }
316 
317 /*
318  * Process a received Ethernet packet;
319  * the packet is in the mbuf chain m without
320  * the ether header, which is provided separately.
321  */
322 void
323 ether_input(ifp, eh, m)
324 	struct ifnet *ifp;
325 	register struct ether_header *eh;
326 	struct mbuf *m;
327 {
328 	register struct ifqueue *inq;
329 	register struct llc *l;
330 	struct arpcom *ac = (struct arpcom *)ifp;
331 	u_short ether_type;
332 	int s;
333 
334 	if ((ifp->if_flags & IFF_UP) == 0) {
335 		m_freem(m);
336 		return;
337 	}
338 	ifp->if_lastchange = time;
339 	ifp->if_ibytes += m->m_pkthdr.len + sizeof (*eh);
340 	if (bcmp((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
341 	    sizeof(etherbroadcastaddr)) == 0)
342 		m->m_flags |= M_BCAST;
343 	else if (eh->ether_dhost[0] & 1)
344 		m->m_flags |= M_MCAST;
345 	if (m->m_flags & (M_BCAST|M_MCAST))
346 		ifp->if_imcasts++;
347 
348 	ether_type = ntohs(eh->ether_type);
349 
350 	switch (ether_type) {
351 #ifdef INET
352 	case ETHERTYPE_IP:
353 		schednetisr(NETISR_IP);
354 		inq = &ipintrq;
355 		break;
356 
357 	case ETHERTYPE_ARP:
358 		schednetisr(NETISR_ARP);
359 		inq = &arpintrq;
360 		break;
361 #endif
362 #ifdef IPX
363 	case ETHERTYPE_IPX:
364 		schednetisr(NETISR_IPX);
365 		inq = &ipxintrq;
366 		break;
367 #endif
368 #ifdef NS
369 	case ETHERTYPE_NS:
370 		schednetisr(NETISR_NS);
371 		inq = &nsintrq;
372 		break;
373 #endif
374 	default:
375 #if defined (ISO) || defined (LLC)
376 		if (ether_type > ETHERMTU)
377 			goto dropanyway;
378 		l = mtod(m, struct llc *);
379 		switch (l->llc_dsap) {
380 #ifdef	ISO
381 		case LLC_ISO_LSAP:
382 			switch (l->llc_control) {
383 			case LLC_UI:
384 				/* LLC_UI_P forbidden in class 1 service */
385 				if ((l->llc_dsap == LLC_ISO_LSAP) &&
386 				    (l->llc_ssap == LLC_ISO_LSAP)) {
387 					/* LSAP for ISO */
388 					if (m->m_pkthdr.len > ether_type)
389 						m_adj(m, ether_type - m->m_pkthdr.len);
390 					m->m_data += 3;		/* XXX */
391 					m->m_len -= 3;		/* XXX */
392 					m->m_pkthdr.len -= 3;	/* XXX */
393 					M_PREPEND(m, sizeof *eh, M_DONTWAIT);
394 					if (m == 0)
395 						return;
396 					*mtod(m, struct ether_header *) = *eh;
397 					IFDEBUG(D_ETHER)
398 						printf("clnp packet");
399 					ENDDEBUG
400 					schednetisr(NETISR_ISO);
401 					inq = &clnlintrq;
402 					break;
403 				}
404 				goto dropanyway;
405 
406 			case LLC_XID:
407 			case LLC_XID_P:
408 				if(m->m_len < 6)
409 					goto dropanyway;
410 				l->llc_window = 0;
411 				l->llc_fid = 9;
412 				l->llc_class = 1;
413 				l->llc_dsap = l->llc_ssap = 0;
414 				/* Fall through to */
415 			case LLC_TEST:
416 			case LLC_TEST_P:
417 			{
418 				struct sockaddr sa;
419 				register struct ether_header *eh2;
420 				int i;
421 				u_char c = l->llc_dsap;
422 
423 				l->llc_dsap = l->llc_ssap;
424 				l->llc_ssap = c;
425 				if (m->m_flags & (M_BCAST | M_MCAST))
426 					bcopy((caddr_t)ac->ac_enaddr,
427 					      (caddr_t)eh->ether_dhost, 6);
428 				sa.sa_family = AF_UNSPEC;
429 				sa.sa_len = sizeof(sa);
430 				eh2 = (struct ether_header *)sa.sa_data;
431 				for (i = 0; i < 6; i++) {
432 					eh2->ether_shost[i] = c = eh->ether_dhost[i];
433 					eh2->ether_dhost[i] =
434 						eh->ether_dhost[i] = eh->ether_shost[i];
435 					eh->ether_shost[i] = c;
436 				}
437 				ifp->if_output(ifp, m, &sa, NULL);
438 				return;
439 			}
440 			default:
441 				m_freem(m);
442 				return;
443 			}
444 			break;
445 #endif /* ISO */
446 #ifdef LLC
447 		case LLC_X25_LSAP:
448 		{
449 			if (m->m_pkthdr.len > ether_type)
450 				m_adj(m, ether_type - m->m_pkthdr.len);
451 			M_PREPEND(m, sizeof(struct sdl_hdr) , M_DONTWAIT);
452 			if (m == 0)
453 				return;
454 			if ( !sdl_sethdrif(ifp, eh->ether_shost, LLC_X25_LSAP,
455 					    eh->ether_dhost, LLC_X25_LSAP, 6,
456 					    mtod(m, struct sdl_hdr *)))
457 				panic("ETHER cons addr failure");
458 			mtod(m, struct sdl_hdr *)->sdlhdr_len = ether_type;
459 #ifdef LLC_DEBUG
460 				printf("llc packet\n");
461 #endif /* LLC_DEBUG */
462 			schednetisr(NETISR_CCITT);
463 			inq = &llcintrq;
464 			break;
465 		}
466 #endif /* LLC */
467 		dropanyway:
468 		default:
469 			m_freem(m);
470 			return;
471 		}
472 #else /* ISO || LLC */
473 	    m_freem(m);
474 	    return;
475 #endif /* ISO || LLC */
476 	}
477 
478 	s = splimp();
479 	if (IF_QFULL(inq)) {
480 		IF_DROP(inq);
481 		m_freem(m);
482 	} else
483 		IF_ENQUEUE(inq, m);
484 	splx(s);
485 }
486 
487 /*
488  * Convert Ethernet address to printable (loggable) representation.
489  */
490 static char digits[] = "0123456789abcdef";
491 char *
492 ether_sprintf(ap)
493 	register u_char *ap;
494 {
495 	register i;
496 	static char etherbuf[18];
497 	register char *cp = etherbuf;
498 
499 	for (i = 0; i < 6; i++) {
500 		*cp++ = digits[*ap >> 4];
501 		*cp++ = digits[*ap++ & 0xf];
502 		*cp++ = ':';
503 	}
504 	*--cp = 0;
505 	return (etherbuf);
506 }
507 
508 /*
509  * Perform common duties while attaching to interface list
510  */
511 void
512 ether_ifattach(ifp)
513 	register struct ifnet *ifp;
514 {
515 	register struct ifaddr *ifa;
516 	register struct sockaddr_dl *sdl;
517 
518 	ifp->if_type = IFT_ETHER;
519 	ifp->if_addrlen = 6;
520 	ifp->if_hdrlen = 14;
521 	ifp->if_mtu = ETHERMTU;
522 	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
523 		if ((sdl = (struct sockaddr_dl *)ifa->ifa_addr) &&
524 		    sdl->sdl_family == AF_LINK) {
525 			sdl->sdl_type = IFT_ETHER;
526 			sdl->sdl_alen = ifp->if_addrlen;
527 			bcopy((caddr_t)((struct arpcom *)ifp)->ac_enaddr,
528 			      LLADDR(sdl), ifp->if_addrlen);
529 			break;
530 		}
531 }
532 
533 u_char	ether_ipmulticast_min[6] = { 0x01, 0x00, 0x5e, 0x00, 0x00, 0x00 };
534 u_char	ether_ipmulticast_max[6] = { 0x01, 0x00, 0x5e, 0x7f, 0xff, 0xff };
535 /*
536  * Add an Ethernet multicast address or range of addresses to the list for a
537  * given interface.
538  */
539 int
540 ether_addmulti(ifr, ac)
541 	struct ifreq *ifr;
542 	register struct arpcom *ac;
543 {
544 	register struct ether_multi *enm;
545 	struct sockaddr_in *sin;
546 	u_char addrlo[6];
547 	u_char addrhi[6];
548       int set_allmulti = 0;
549 	int s = splimp();
550 
551 	switch (ifr->ifr_addr.sa_family) {
552 
553 	case AF_UNSPEC:
554 		bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
555 		bcopy(addrlo, addrhi, 6);
556 		break;
557 
558 #ifdef INET
559 	case AF_INET:
560 		sin = (struct sockaddr_in *)&(ifr->ifr_addr);
561 		if (sin->sin_addr.s_addr == INADDR_ANY) {
562 			/*
563 			 * An IP address of INADDR_ANY means listen to all
564 			 * of the Ethernet multicast addresses used for IP.
565 			 * (This is for the sake of IP multicast routers.)
566 			 */
567 			bcopy(ether_ipmulticast_min, addrlo, 6);
568 			bcopy(ether_ipmulticast_max, addrhi, 6);
569                       set_allmulti = 1;
570 		}
571 		else {
572 			ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
573 			bcopy(addrlo, addrhi, 6);
574 		}
575 		break;
576 #endif
577 
578 	default:
579 		splx(s);
580 		return (EAFNOSUPPORT);
581 	}
582 
583 	/*
584 	 * Verify that we have valid Ethernet multicast addresses.
585 	 */
586 	if ((addrlo[0] & 0x01) != 1 || (addrhi[0] & 0x01) != 1) {
587 		splx(s);
588 		return (EINVAL);
589 	}
590 	/*
591 	 * See if the address range is already in the list.
592 	 */
593 	ETHER_LOOKUP_MULTI(addrlo, addrhi, ac, enm);
594 	if (enm != NULL) {
595 		/*
596 		 * Found it; just increment the reference count.
597 		 */
598 		++enm->enm_refcount;
599 		splx(s);
600 		return (0);
601 	}
602 	/*
603 	 * New address or range; malloc a new multicast record
604 	 * and link it into the interface's multicast list.
605 	 */
606 	enm = (struct ether_multi *)malloc(sizeof(*enm), M_IFMADDR, M_NOWAIT);
607 	if (enm == NULL) {
608 		splx(s);
609 		return (ENOBUFS);
610 	}
611 	bcopy(addrlo, enm->enm_addrlo, 6);
612 	bcopy(addrhi, enm->enm_addrhi, 6);
613 	enm->enm_ac = ac;
614 	enm->enm_refcount = 1;
615 	enm->enm_next = ac->ac_multiaddrs;
616 	ac->ac_multiaddrs = enm;
617 	ac->ac_multicnt++;
618 	splx(s);
619       if (set_allmulti)
620               ac->ac_if.if_flags |= IFF_ALLMULTI;
621 
622 	/*
623 	 * Return ENETRESET to inform the driver that the list has changed
624 	 * and its reception filter should be adjusted accordingly.
625 	 */
626 	return (ENETRESET);
627 }
628 
629 /*
630  * Delete a multicast address record.
631  */
632 int
633 ether_delmulti(ifr, ac)
634 	struct ifreq *ifr;
635 	register struct arpcom *ac;
636 {
637 	register struct ether_multi *enm;
638 	register struct ether_multi **p;
639 	struct sockaddr_in *sin;
640 	u_char addrlo[6];
641 	u_char addrhi[6];
642       int unset_allmulti = 0;
643 	int s = splimp();
644 
645 	switch (ifr->ifr_addr.sa_family) {
646 
647 	case AF_UNSPEC:
648 		bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
649 		bcopy(addrlo, addrhi, 6);
650 		break;
651 
652 #ifdef INET
653 	case AF_INET:
654 		sin = (struct sockaddr_in *)&(ifr->ifr_addr);
655 		if (sin->sin_addr.s_addr == INADDR_ANY) {
656 			/*
657 			 * An IP address of INADDR_ANY means stop listening
658 			 * to the range of Ethernet multicast addresses used
659 			 * for IP.
660 			 */
661 			bcopy(ether_ipmulticast_min, addrlo, 6);
662 			bcopy(ether_ipmulticast_max, addrhi, 6);
663                       unset_allmulti = 1;
664 		}
665 		else {
666 			ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
667 			bcopy(addrlo, addrhi, 6);
668 		}
669 		break;
670 #endif
671 
672 	default:
673 		splx(s);
674 		return (EAFNOSUPPORT);
675 	}
676 
677 	/*
678 	 * Look up the address in our list.
679 	 */
680 	ETHER_LOOKUP_MULTI(addrlo, addrhi, ac, enm);
681 	if (enm == NULL) {
682 		splx(s);
683 		return (ENXIO);
684 	}
685 	if (--enm->enm_refcount != 0) {
686 		/*
687 		 * Still some claims to this record.
688 		 */
689 		splx(s);
690 		return (0);
691 	}
692 	/*
693 	 * No remaining claims to this record; unlink and free it.
694 	 */
695 	for (p = &enm->enm_ac->ac_multiaddrs;
696 	     *p != enm;
697 	     p = &(*p)->enm_next)
698 		continue;
699 	*p = (*p)->enm_next;
700 	free(enm, M_IFMADDR);
701 	ac->ac_multicnt--;
702 	splx(s);
703       if (unset_allmulti)
704               ac->ac_if.if_flags &= ~IFF_ALLMULTI;
705 
706 	/*
707 	 * Return ENETRESET to inform the driver that the list has changed
708 	 * and its reception filter should be adjusted accordingly.
709 	 */
710 	return (ENETRESET);
711 }
712