xref: /netbsd-src/sys/net/if_vlan.c (revision d20841bb642898112fe68f0ad3f7b26dddf56f07)
1 /*	$NetBSD: if_vlan.c,v 1.38 2003/12/05 19:35:43 scw Exp $	*/
2 
3 /*-
4  * Copyright (c) 2000, 2001 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Andrew Doran, and by Jason R. Thorpe of Zembu Labs, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the NetBSD
21  *	Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Copyright 1998 Massachusetts Institute of Technology
41  *
42  * Permission to use, copy, modify, and distribute this software and
43  * its documentation for any purpose and without fee is hereby
44  * granted, provided that both the above copyright notice and this
45  * permission notice appear in all copies, that both the above
46  * copyright notice and this permission notice appear in all
47  * supporting documentation, and that the name of M.I.T. not be used
48  * in advertising or publicity pertaining to distribution of the
49  * software without specific, written prior permission.  M.I.T. makes
50  * no representations about the suitability of this software for any
51  * purpose.  It is provided "as is" without express or implied
52  * warranty.
53  *
54  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
55  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
56  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
57  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
58  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
59  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
60  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
61  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
62  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
63  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
64  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
65  * SUCH DAMAGE.
66  *
67  * from FreeBSD: if_vlan.c,v 1.16 2000/03/26 15:21:40 charnier Exp
68  * via OpenBSD: if_vlan.c,v 1.4 2000/05/15 19:15:00 chris Exp
69  */
70 
71 /*
72  * if_vlan.c - pseudo-device driver for IEEE 802.1Q virtual LANs.  Might be
73  * extended some day to also handle IEEE 802.1P priority tagging.  This is
74  * sort of sneaky in the implementation, since we need to pretend to be
75  * enough of an Ethernet implementation to make ARP work.  The way we do
76  * this is by telling everyone that we are an Ethernet interface, and then
77  * catch the packets that ether_output() left on our output queue when it
78  * calls if_start(), rewrite them for use by the real outgoing interface,
79  * and ask it to send them.
80  *
81  * TODO:
82  *
83  *	- Need some way to notify vlan interfaces when the parent
84  *	  interface changes MTU.
85  */
86 
87 #include <sys/cdefs.h>
88 __KERNEL_RCSID(0, "$NetBSD: if_vlan.c,v 1.38 2003/12/05 19:35:43 scw Exp $");
89 
90 #include "opt_inet.h"
91 #include "bpfilter.h"
92 
93 #include <sys/param.h>
94 #include <sys/kernel.h>
95 #include <sys/mbuf.h>
96 #include <sys/queue.h>
97 #include <sys/socket.h>
98 #include <sys/sockio.h>
99 #include <sys/systm.h>
100 #include <sys/proc.h>
101 
102 #if NBPFILTER > 0
103 #include <net/bpf.h>
104 #endif
105 #include <net/if.h>
106 #include <net/if_dl.h>
107 #include <net/if_types.h>
108 #include <net/if_ether.h>
109 #include <net/if_vlanvar.h>
110 
111 #ifdef INET
112 #include <netinet/in.h>
113 #include <netinet/if_inarp.h>
114 #endif
115 
116 struct vlan_mc_entry {
117 	LIST_ENTRY(vlan_mc_entry)	mc_entries;
118 	/*
119 	 * A key to identify this entry.  The mc_addr below can't be
120 	 * used since multiple sockaddr may mapped into the same
121 	 * ether_multi (e.g., AF_UNSPEC).
122 	 */
123 	union {
124 		struct ether_multi	*mcu_enm;
125 	} mc_u;
126 	struct sockaddr_storage		mc_addr;
127 };
128 
129 #define	mc_enm		mc_u.mcu_enm
130 
131 struct ifvlan {
132 	union {
133 		struct ethercom ifvu_ec;
134 	} ifv_u;
135 	struct ifnet *ifv_p;	/* parent interface of this vlan */
136 	struct ifv_linkmib {
137 		const struct vlan_multisw *ifvm_msw;
138 		int	ifvm_encaplen;	/* encapsulation length */
139 		int	ifvm_mtufudge;	/* MTU fudged by this much */
140 		int	ifvm_mintu;	/* min transmission unit */
141 		u_int16_t ifvm_proto;	/* encapsulation ethertype */
142 		u_int16_t ifvm_tag;	/* tag to apply on packets */
143 	} ifv_mib;
144 	LIST_HEAD(__vlan_mchead, vlan_mc_entry) ifv_mc_listhead;
145 	LIST_ENTRY(ifvlan) ifv_list;
146 	int ifv_flags;
147 };
148 
149 #define	IFVF_PROMISC	0x01		/* promiscuous mode enabled */
150 
151 #define	ifv_ec		ifv_u.ifvu_ec
152 
153 #define	ifv_if		ifv_ec.ec_if
154 
155 #define	ifv_msw		ifv_mib.ifvm_msw
156 #define	ifv_encaplen	ifv_mib.ifvm_encaplen
157 #define	ifv_mtufudge	ifv_mib.ifvm_mtufudge
158 #define	ifv_mintu	ifv_mib.ifvm_mintu
159 #define	ifv_tag		ifv_mib.ifvm_tag
160 
161 struct vlan_multisw {
162 	int	(*vmsw_addmulti)(struct ifvlan *, struct ifreq *);
163 	int	(*vmsw_delmulti)(struct ifvlan *, struct ifreq *);
164 	void	(*vmsw_purgemulti)(struct ifvlan *);
165 };
166 
167 static int	vlan_ether_addmulti(struct ifvlan *, struct ifreq *);
168 static int	vlan_ether_delmulti(struct ifvlan *, struct ifreq *);
169 static void	vlan_ether_purgemulti(struct ifvlan *);
170 
171 const struct vlan_multisw vlan_ether_multisw = {
172 	vlan_ether_addmulti,
173 	vlan_ether_delmulti,
174 	vlan_ether_purgemulti,
175 };
176 
177 static int	vlan_clone_create(struct if_clone *, int);
178 static void	vlan_clone_destroy(struct ifnet *);
179 static int	vlan_config(struct ifvlan *, struct ifnet *);
180 static int	vlan_ioctl(struct ifnet *, u_long, caddr_t);
181 static void	vlan_start(struct ifnet *);
182 static void	vlan_unconfig(struct ifnet *);
183 
184 void		vlanattach(int);
185 
186 /* XXX This should be a hash table with the tag as the basis of the key. */
187 static LIST_HEAD(, ifvlan) ifv_list;
188 
189 struct if_clone vlan_cloner =
190     IF_CLONE_INITIALIZER("vlan", vlan_clone_create, vlan_clone_destroy);
191 
192 /* Used to pad ethernet frames with < ETHER_MIN_LEN bytes */
193 static char vlan_zero_pad_buff[ETHER_MIN_LEN];
194 
195 void
196 vlanattach(int n)
197 {
198 
199 	LIST_INIT(&ifv_list);
200 	if_clone_attach(&vlan_cloner);
201 }
202 
203 static void
204 vlan_reset_linkname(struct ifnet *ifp)
205 {
206 
207 	/*
208 	 * We start out with a "802.1Q VLAN" type and zero-length
209 	 * addresses.  When we attach to a parent interface, we
210 	 * inherit its type, address length, address, and data link
211 	 * type.
212 	 */
213 
214 	ifp->if_type = IFT_L2VLAN;
215 	ifp->if_addrlen = 0;
216 	ifp->if_dlt = DLT_NULL;
217 	if_alloc_sadl(ifp);
218 }
219 
220 static int
221 vlan_clone_create(struct if_clone *ifc, int unit)
222 {
223 	struct ifvlan *ifv;
224 	struct ifnet *ifp;
225 	int s;
226 
227 	ifv = malloc(sizeof(struct ifvlan), M_DEVBUF, M_WAITOK);
228 	memset(ifv, 0, sizeof(struct ifvlan));
229 	ifp = &ifv->ifv_if;
230 	LIST_INIT(&ifv->ifv_mc_listhead);
231 
232 	s = splnet();
233 	LIST_INSERT_HEAD(&ifv_list, ifv, ifv_list);
234 	splx(s);
235 
236 	sprintf(ifp->if_xname, "%s%d", ifc->ifc_name, unit);
237 	ifp->if_softc = ifv;
238 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
239 	ifp->if_start = vlan_start;
240 	ifp->if_ioctl = vlan_ioctl;
241 	IFQ_SET_READY(&ifp->if_snd);
242 
243 	if_attach(ifp);
244 	vlan_reset_linkname(ifp);
245 
246 	return (0);
247 }
248 
249 static void
250 vlan_clone_destroy(struct ifnet *ifp)
251 {
252 	struct ifvlan *ifv = ifp->if_softc;
253 	int s;
254 
255 	s = splnet();
256 	LIST_REMOVE(ifv, ifv_list);
257 	vlan_unconfig(ifp);
258 	splx(s);
259 
260 	if_detach(ifp);
261 	free(ifv, M_DEVBUF);
262 }
263 
264 /*
265  * Configure a VLAN interface.  Must be called at splnet().
266  */
267 static int
268 vlan_config(struct ifvlan *ifv, struct ifnet *p)
269 {
270 	struct ifnet *ifp = &ifv->ifv_if;
271 	int error;
272 
273 	if (ifv->ifv_p != NULL)
274 		return (EBUSY);
275 
276 	switch (p->if_type) {
277 	case IFT_ETHER:
278 	    {
279 		struct ethercom *ec = (void *) p;
280 
281 		ifv->ifv_msw = &vlan_ether_multisw;
282 		ifv->ifv_encaplen = ETHER_VLAN_ENCAP_LEN;
283 		ifv->ifv_mintu = ETHERMIN;
284 
285 		/*
286 		 * If the parent supports the VLAN_MTU capability,
287 		 * i.e. can Tx/Rx larger than ETHER_MAX_LEN frames,
288 		 * enable it.
289 		 */
290 		if (ec->ec_nvlans++ == 0 &&
291 		    (ec->ec_capabilities & ETHERCAP_VLAN_MTU) != 0) {
292 			/*
293 			 * Enable Tx/Rx of VLAN-sized frames.
294 			 */
295 			ec->ec_capenable |= ETHERCAP_VLAN_MTU;
296 			if (p->if_flags & IFF_UP) {
297 				struct ifreq ifr;
298 
299 				ifr.ifr_flags = p->if_flags;
300 				error = (*p->if_ioctl)(p, SIOCSIFFLAGS,
301 				    (caddr_t) &ifr);
302 				if (error) {
303 					if (ec->ec_nvlans-- == 1)
304 						ec->ec_capenable &=
305 						    ~ETHERCAP_VLAN_MTU;
306 					return (error);
307 				}
308 			}
309 			ifv->ifv_mtufudge = 0;
310 		} else if ((ec->ec_capabilities & ETHERCAP_VLAN_MTU) == 0) {
311 			/*
312 			 * Fudge the MTU by the encapsulation size.  This
313 			 * makes us incompatible with strictly compliant
314 			 * 802.1Q implementations, but allows us to use
315 			 * the feature with other NetBSD implementations,
316 			 * which might still be useful.
317 			 */
318 			ifv->ifv_mtufudge = ifv->ifv_encaplen;
319 		}
320 
321 		/*
322 		 * If the parent interface can do hardware-assisted
323 		 * VLAN encapsulation, then propagate its hardware-
324 		 * assisted checksumming flags.
325 		 */
326 		if (ec->ec_capabilities & ETHERCAP_VLAN_HWTAGGING)
327 			ifp->if_capabilities = p->if_capabilities &
328 			    (IFCAP_CSUM_IPv4|IFCAP_CSUM_TCPv4|
329 			     IFCAP_CSUM_UDPv4|IFCAP_CSUM_TCPv6|
330 			     IFCAP_CSUM_UDPv6);
331 
332 		/*
333 		 * We inherit the parent's Ethernet address.
334 		 */
335 		ether_ifattach(ifp, LLADDR(p->if_sadl));
336 		ifp->if_hdrlen = sizeof(struct ether_vlan_header); /* XXX? */
337 		break;
338 	    }
339 
340 	default:
341 		return (EPROTONOSUPPORT);
342 	}
343 
344 	ifv->ifv_p = p;
345 	ifv->ifv_if.if_mtu = p->if_mtu - ifv->ifv_mtufudge;
346 	ifv->ifv_if.if_flags = p->if_flags &
347 	    (IFF_UP | IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
348 
349 	/*
350 	 * Inherit the if_type from the parent.  This allows us
351 	 * to participate in bridges of that type.
352 	 */
353 	ifv->ifv_if.if_type = p->if_type;
354 
355 	return (0);
356 }
357 
358 /*
359  * Unconfigure a VLAN interface.  Must be called at splnet().
360  */
361 static void
362 vlan_unconfig(struct ifnet *ifp)
363 {
364 	struct ifvlan *ifv = ifp->if_softc;
365 
366 	if (ifv->ifv_p == NULL)
367 		return;
368 
369 	/*
370  	 * Since the interface is being unconfigured, we need to empty the
371 	 * list of multicast groups that we may have joined while we were
372 	 * alive and remove them from the parent's list also.
373 	 */
374 	(*ifv->ifv_msw->vmsw_purgemulti)(ifv);
375 
376 	/* Disconnect from parent. */
377 	switch (ifv->ifv_p->if_type) {
378 	case IFT_ETHER:
379 	    {
380 		struct ethercom *ec = (void *) ifv->ifv_p;
381 
382 		if (ec->ec_nvlans-- == 1) {
383 			/*
384 			 * Disable Tx/Rx of VLAN-sized frames.
385 			 */
386 			ec->ec_capenable &= ~ETHERCAP_VLAN_MTU;
387 			if (ifv->ifv_p->if_flags & IFF_UP) {
388 				struct ifreq ifr;
389 
390 				ifr.ifr_flags = ifv->ifv_p->if_flags;
391 				(void) (*ifv->ifv_p->if_ioctl)(ifv->ifv_p,
392 				    SIOCSIFFLAGS, (caddr_t) &ifr);
393 			}
394 		}
395 
396 		ether_ifdetach(ifp);
397 		vlan_reset_linkname(ifp);
398 		break;
399 	    }
400 
401 #ifdef DIAGNOSTIC
402 	default:
403 		panic("vlan_unconfig: impossible");
404 #endif
405 	}
406 
407 	ifv->ifv_p = NULL;
408 	ifv->ifv_if.if_mtu = 0;
409 	ifv->ifv_flags = 0;
410 
411 	if_down(ifp);
412 	ifp->if_flags &= ~(IFF_UP|IFF_RUNNING);
413 	ifp->if_capabilities = 0;
414 }
415 
416 /*
417  * Called when a parent interface is detaching; destroy any VLAN
418  * configuration for the parent interface.
419  */
420 void
421 vlan_ifdetach(struct ifnet *p)
422 {
423 	struct ifvlan *ifv;
424 	int s;
425 
426 	s = splnet();
427 
428 	for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
429 	     ifv = LIST_NEXT(ifv, ifv_list)) {
430 		if (ifv->ifv_p == p)
431 			vlan_unconfig(&ifv->ifv_if);
432 	}
433 
434 	splx(s);
435 }
436 
437 static int
438 vlan_set_promisc(struct ifnet *ifp)
439 {
440 	struct ifvlan *ifv = ifp->if_softc;
441 	int error = 0;
442 
443 	if ((ifp->if_flags & IFF_PROMISC) != 0) {
444 		if ((ifv->ifv_flags & IFVF_PROMISC) == 0) {
445 			error = ifpromisc(ifv->ifv_p, 1);
446 			if (error == 0)
447 				ifv->ifv_flags |= IFVF_PROMISC;
448 		}
449 	} else {
450 		if ((ifv->ifv_flags & IFVF_PROMISC) != 0) {
451 			error = ifpromisc(ifv->ifv_p, 0);
452 			if (error == 0)
453 				ifv->ifv_flags &= ~IFVF_PROMISC;
454 		}
455 	}
456 
457 	return (error);
458 }
459 
460 static int
461 vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
462 {
463 	struct proc *p = curproc;	/* XXX */
464 	struct ifvlan *ifv = ifp->if_softc;
465 	struct ifaddr *ifa = (struct ifaddr *) data;
466 	struct ifreq *ifr = (struct ifreq *) data;
467 	struct ifnet *pr;
468 	struct vlanreq vlr;
469 	struct sockaddr *sa;
470 	int s, error = 0;
471 
472 	s = splnet();
473 
474 	switch (cmd) {
475 	case SIOCSIFADDR:
476 		if (ifv->ifv_p != NULL) {
477 			ifp->if_flags |= IFF_UP;
478 
479 			switch (ifa->ifa_addr->sa_family) {
480 #ifdef INET
481 			case AF_INET:
482 				arp_ifinit(ifp, ifa);
483 				break;
484 #endif
485 			default:
486 				break;
487 			}
488 		} else {
489 			error = EINVAL;
490 		}
491 		break;
492 
493 	case SIOCGIFADDR:
494 		sa = (struct sockaddr *)&ifr->ifr_data;
495 		memcpy(sa->sa_data, LLADDR(ifp->if_sadl), ifp->if_addrlen);
496 		break;
497 
498 	case SIOCSIFMTU:
499 		if (ifv->ifv_p != NULL) {
500 			if (ifr->ifr_mtu >
501 			     (ifv->ifv_p->if_mtu - ifv->ifv_mtufudge) ||
502 			    ifr->ifr_mtu <
503 			     (ifv->ifv_mintu - ifv->ifv_mtufudge))
504 				error = EINVAL;
505 			else
506 				ifp->if_mtu = ifr->ifr_mtu;
507 		} else
508 			error = EINVAL;
509 		break;
510 
511 	case SIOCSETVLAN:
512 		if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
513 			break;
514 		if ((error = copyin(ifr->ifr_data, &vlr, sizeof(vlr))) != 0)
515 			break;
516 		if (vlr.vlr_parent[0] == '\0') {
517 			vlan_unconfig(ifp);
518 			break;
519 		}
520 		if (vlr.vlr_tag != EVL_VLANOFTAG(vlr.vlr_tag)) {
521 			error = EINVAL;		 /* check for valid tag */
522 			break;
523 		}
524 		if ((pr = ifunit(vlr.vlr_parent)) == 0) {
525 			error = ENOENT;
526 			break;
527 		}
528 		if ((error = vlan_config(ifv, pr)) != 0)
529 			break;
530 		ifv->ifv_tag = vlr.vlr_tag;
531 		ifp->if_flags |= IFF_RUNNING;
532 
533 		/* Update promiscuous mode, if necessary. */
534 		vlan_set_promisc(ifp);
535 		break;
536 
537 	case SIOCGETVLAN:
538 		memset(&vlr, 0, sizeof(vlr));
539 		if (ifv->ifv_p != NULL) {
540 			snprintf(vlr.vlr_parent, sizeof(vlr.vlr_parent), "%s",
541 			    ifv->ifv_p->if_xname);
542 			vlr.vlr_tag = ifv->ifv_tag;
543 		}
544 		error = copyout(&vlr, ifr->ifr_data, sizeof(vlr));
545 		break;
546 
547 	case SIOCSIFFLAGS:
548 		/*
549 		 * For promiscuous mode, we enable promiscuous mode on
550 		 * the parent if we need promiscuous on the VLAN interface.
551 		 */
552 		if (ifv->ifv_p != NULL)
553 			error = vlan_set_promisc(ifp);
554 		break;
555 
556 	case SIOCADDMULTI:
557 		error = (ifv->ifv_p != NULL) ?
558 		    (*ifv->ifv_msw->vmsw_addmulti)(ifv, ifr) : EINVAL;
559 		break;
560 
561 	case SIOCDELMULTI:
562 		error = (ifv->ifv_p != NULL) ?
563 		    (*ifv->ifv_msw->vmsw_delmulti)(ifv, ifr) : EINVAL;
564 		break;
565 
566 	default:
567 		error = EINVAL;
568 	}
569 
570 	splx(s);
571 
572 	return (error);
573 }
574 
575 static int
576 vlan_ether_addmulti(struct ifvlan *ifv, struct ifreq *ifr)
577 {
578 	struct vlan_mc_entry *mc;
579 	u_int8_t addrlo[ETHER_ADDR_LEN], addrhi[ETHER_ADDR_LEN];
580 	int error;
581 
582 	if (ifr->ifr_addr.sa_len > sizeof(struct sockaddr_storage))
583 		return (EINVAL);
584 
585 	error = ether_addmulti(ifr, &ifv->ifv_ec);
586 	if (error != ENETRESET)
587 		return (error);
588 
589 	/*
590 	 * This is new multicast address.  We have to tell parent
591 	 * about it.  Also, remember this multicast address so that
592 	 * we can delete them on unconfigure.
593 	 */
594 	MALLOC(mc, struct vlan_mc_entry *, sizeof(struct vlan_mc_entry),
595 	    M_DEVBUF, M_NOWAIT);
596 	if (mc == NULL) {
597 		error = ENOMEM;
598 		goto alloc_failed;
599 	}
600 
601 	/*
602 	 * As ether_addmulti() returns ENETRESET, following two
603 	 * statement shouldn't fail.
604 	 */
605 	(void)ether_multiaddr(&ifr->ifr_addr, addrlo, addrhi);
606 	ETHER_LOOKUP_MULTI(addrlo, addrhi, &ifv->ifv_ec, mc->mc_enm);
607 	memcpy(&mc->mc_addr, &ifr->ifr_addr, ifr->ifr_addr.sa_len);
608 	LIST_INSERT_HEAD(&ifv->ifv_mc_listhead, mc, mc_entries);
609 
610 	error = (*ifv->ifv_p->if_ioctl)(ifv->ifv_p, SIOCADDMULTI,
611 	    (caddr_t)ifr);
612 	if (error != 0)
613 		goto ioctl_failed;
614 	return (error);
615 
616  ioctl_failed:
617 	LIST_REMOVE(mc, mc_entries);
618 	FREE(mc, M_DEVBUF);
619  alloc_failed:
620 	(void)ether_delmulti(ifr, &ifv->ifv_ec);
621 	return (error);
622 }
623 
624 static int
625 vlan_ether_delmulti(struct ifvlan *ifv, struct ifreq *ifr)
626 {
627 	struct ether_multi *enm;
628 	struct vlan_mc_entry *mc;
629 	u_int8_t addrlo[ETHER_ADDR_LEN], addrhi[ETHER_ADDR_LEN];
630 	int error;
631 
632 	/*
633 	 * Find a key to lookup vlan_mc_entry.  We have to do this
634 	 * before calling ether_delmulti for obvious reason.
635 	 */
636 	if ((error = ether_multiaddr(&ifr->ifr_addr, addrlo, addrhi)) != 0)
637 		return (error);
638 	ETHER_LOOKUP_MULTI(addrlo, addrhi, &ifv->ifv_ec, enm);
639 
640 	error = ether_delmulti(ifr, &ifv->ifv_ec);
641 	if (error != ENETRESET)
642 		return (error);
643 
644 	/* We no longer use this multicast address.  Tell parent so. */
645 	error = (*ifv->ifv_p->if_ioctl)(ifv->ifv_p, SIOCDELMULTI,
646 	    (caddr_t)ifr);
647 	if (error == 0) {
648 		/* And forget about this address. */
649 		for (mc = LIST_FIRST(&ifv->ifv_mc_listhead); mc != NULL;
650 		    mc = LIST_NEXT(mc, mc_entries)) {
651 			if (mc->mc_enm == enm) {
652 				LIST_REMOVE(mc, mc_entries);
653 				FREE(mc, M_DEVBUF);
654 				break;
655 			}
656 		}
657 		KASSERT(mc != NULL);
658 	} else
659 		(void)ether_addmulti(ifr, &ifv->ifv_ec);
660 	return (error);
661 }
662 
663 /*
664  * Delete any multicast address we have asked to add from parent
665  * interface.  Called when the vlan is being unconfigured.
666  */
667 static void
668 vlan_ether_purgemulti(struct ifvlan *ifv)
669 {
670 	struct ifnet *ifp = ifv->ifv_p;		/* Parent. */
671 	struct vlan_mc_entry *mc;
672 	union {
673 		struct ifreq ifreq;
674 		struct {
675 			char ifr_name[IFNAMSIZ];
676 			struct sockaddr_storage ifr_ss;
677 		} ifreq_storage;
678 	} ifreq;
679 	struct ifreq *ifr = &ifreq.ifreq;
680 
681 	memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ);
682 	while ((mc = LIST_FIRST(&ifv->ifv_mc_listhead)) != NULL) {
683 		memcpy(&ifr->ifr_addr, &mc->mc_addr, mc->mc_addr.ss_len);
684 		(void)(*ifp->if_ioctl)(ifp, SIOCDELMULTI, (caddr_t)ifr);
685 		LIST_REMOVE(mc, mc_entries);
686 		FREE(mc, M_DEVBUF);
687 	}
688 }
689 
690 static void
691 vlan_start(struct ifnet *ifp)
692 {
693 	struct ifvlan *ifv = ifp->if_softc;
694 	struct ifnet *p = ifv->ifv_p;
695 	struct ethercom *ec = (void *) ifv->ifv_p;
696 	struct mbuf *m;
697 	int error;
698 	ALTQ_DECL(struct altq_pktattr pktattr;)
699 
700 	ifp->if_flags |= IFF_OACTIVE;
701 
702 	for (;;) {
703 		IFQ_DEQUEUE(&ifp->if_snd, m);
704 		if (m == NULL)
705 			break;
706 
707 #ifdef ALTQ
708 		/*
709 		 * If ALTQ is enabled on the parent interface, do
710 		 * classification; the queueing discipline might
711 		 * not require classification, but might require
712 		 * the address family/header pointer in the pktattr.
713 		 */
714 		if (ALTQ_IS_ENABLED(&p->if_snd)) {
715 			switch (p->if_type) {
716 			case IFT_ETHER:
717 				altq_etherclassify(&p->if_snd, m, &pktattr);
718 				break;
719 #ifdef DIAGNOSTIC
720 			default:
721 				panic("vlan_start: impossible (altq)");
722 #endif
723 			}
724 		}
725 #endif /* ALTQ */
726 
727 #if NBPFILTER > 0
728 		if (ifp->if_bpf)
729 			bpf_mtap(ifp->if_bpf, m);
730 #endif
731 		/*
732 		 * If the parent can insert the tag itself, just mark
733 		 * the tag in the mbuf header.
734 		 */
735 		if (ec->ec_capabilities & ETHERCAP_VLAN_HWTAGGING) {
736 			struct m_tag *mtag;
737 
738 			mtag = m_tag_get(PACKET_TAG_VLAN, sizeof(u_int),
739 			    M_NOWAIT);
740 			if (mtag == NULL) {
741 				ifp->if_oerrors++;
742 				m_freem(m);
743 				continue;
744 			}
745 			*(u_int *)(mtag + 1) = ifv->ifv_tag;
746 			m_tag_prepend(m, mtag);
747 		} else {
748 			/*
749 			 * insert the tag ourselves
750 			 */
751 			M_PREPEND(m, ifv->ifv_encaplen, M_DONTWAIT);
752 			if (m == NULL) {
753 				printf("%s: unable to prepend encap header",
754 				    ifv->ifv_p->if_xname);
755 				ifp->if_oerrors++;
756 				continue;
757 			}
758 
759 			switch (p->if_type) {
760 			case IFT_ETHER:
761 			    {
762 				struct ether_vlan_header *evl;
763 
764 				if (m->m_len < sizeof(struct ether_vlan_header))
765 					m = m_pullup(m,
766 					    sizeof(struct ether_vlan_header));
767 				if (m == NULL) {
768 					printf("%s: unable to pullup encap "
769 					    "header", ifv->ifv_p->if_xname);
770 					ifp->if_oerrors++;
771 					continue;
772 				}
773 
774 				/*
775 				 * Transform the Ethernet header into an
776 				 * Ethernet header with 802.1Q encapsulation.
777 				 */
778 				memmove(mtod(m, caddr_t),
779 				    mtod(m, caddr_t) + ifv->ifv_encaplen,
780 				    sizeof(struct ether_header));
781 				evl = mtod(m, struct ether_vlan_header *);
782 				evl->evl_proto = evl->evl_encap_proto;
783 				evl->evl_encap_proto = htons(ETHERTYPE_VLAN);
784 				evl->evl_tag = htons(ifv->ifv_tag);
785 
786 				/*
787 				 * To cater for VLAN-aware layer 2 ethernet
788 				 * switches which may need to strip the tag
789 				 * before forwarding the packet, make sure
790 				 * the packet+tag is at least 68 bytes long.
791 				 * This is necessary because our parent will
792 				 * only pad to 64 bytes (ETHER_MIN_LEN) and
793 				 * some switches will not pad by themselves
794 				 * after deleting a tag.
795 				 */
796 				if (m->m_pkthdr.len <
797 				    (ETHER_MIN_LEN + ETHER_VLAN_ENCAP_LEN)) {
798 					m_copyback(m, m->m_pkthdr.len,
799 					    (ETHER_MIN_LEN +
800 					     ETHER_VLAN_ENCAP_LEN) -
801 					     m->m_pkthdr.len,
802 					    vlan_zero_pad_buff);
803 				}
804 				break;
805 			    }
806 
807 #ifdef DIAGNOSTIC
808 			default:
809 				panic("vlan_start: impossible");
810 #endif
811 			}
812 		}
813 
814 		/*
815 		 * Send it, precisely as the parent's output routine
816 		 * would have.  We are already running at splnet.
817 		 */
818 		IFQ_ENQUEUE(&p->if_snd, m, &pktattr, error);
819 		if (error) {
820 			/* mbuf is already freed */
821 			ifp->if_oerrors++;
822 			continue;
823 		}
824 
825 		ifp->if_opackets++;
826 		if ((p->if_flags & IFF_OACTIVE) == 0)
827 			(*p->if_start)(p);
828 	}
829 
830 	ifp->if_flags &= ~IFF_OACTIVE;
831 }
832 
833 /*
834  * Given an Ethernet frame, find a valid vlan interface corresponding to the
835  * given source interface and tag, then run the the real packet through
836  * the parent's input routine.
837  */
838 void
839 vlan_input(struct ifnet *ifp, struct mbuf *m)
840 {
841 	struct ifvlan *ifv;
842 	u_int tag;
843 	struct m_tag *mtag;
844 
845 	mtag = m_tag_find(m, PACKET_TAG_VLAN, NULL);
846 	if (mtag != NULL) {
847 		/* m contains a normal ethernet frame, the tag is in mtag */
848 		tag = *(u_int *)(mtag + 1);
849 		m_tag_delete(m, mtag);
850 		for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
851 		    ifv = LIST_NEXT(ifv, ifv_list))
852 			if (ifp == ifv->ifv_p && tag == ifv->ifv_tag)
853 				break;
854 	} else {
855 		switch (ifp->if_type) {
856 		case IFT_ETHER:
857 		    {
858 			struct ether_vlan_header *evl;
859 
860 			if (m->m_len < sizeof(struct ether_vlan_header) &&
861 			    (m = m_pullup(m,
862 			     sizeof(struct ether_vlan_header))) == NULL) {
863 				printf("%s: no memory for VLAN header, "
864 				    "dropping packet.\n", ifp->if_xname);
865 				return;
866 			}
867 			evl = mtod(m, struct ether_vlan_header *);
868 			KASSERT(ntohs(evl->evl_encap_proto) == ETHERTYPE_VLAN);
869 
870 			tag = EVL_VLANOFTAG(ntohs(evl->evl_tag));
871 
872 			/*
873 			 * Restore the original ethertype.  We'll remove
874 			 * the encapsulation after we've found the vlan
875 			 * interface corresponding to the tag.
876 			 */
877 			evl->evl_encap_proto = evl->evl_proto;
878 			break;
879 		    }
880 
881 		default:
882 			tag = (u_int) -1;	/* XXX GCC */
883 #ifdef DIAGNOSTIC
884 			panic("vlan_input: impossible");
885 #endif
886 		}
887 
888 		for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
889 		     ifv = LIST_NEXT(ifv, ifv_list))
890 			if (ifp == ifv->ifv_p && tag == ifv->ifv_tag)
891 				break;
892 
893 
894 		/*
895 		 * Now, remove the encapsulation header.  The original
896 		 * header has already been fixed up above.
897 		 */
898 		if (ifv) {
899 			memmove(mtod(m, caddr_t) + ifv->ifv_encaplen,
900 			    mtod(m, caddr_t), sizeof(struct ether_header));
901 			m_adj(m, ifv->ifv_encaplen);
902 		}
903 	}
904 
905 	if (ifv == NULL ||
906 	    (ifv->ifv_if.if_flags & (IFF_UP|IFF_RUNNING)) !=
907 	     (IFF_UP|IFF_RUNNING)) {
908 		m_freem(m);
909 		ifp->if_noproto++;
910 		return;
911 	}
912 	m->m_pkthdr.rcvif = &ifv->ifv_if;
913 	ifv->ifv_if.if_ipackets++;
914 
915 #if NBPFILTER > 0
916 	if (ifv->ifv_if.if_bpf)
917 		bpf_mtap(ifv->ifv_if.if_bpf, m);
918 #endif
919 
920 	/* Pass it back through the parent's input routine. */
921 	(*ifp->if_input)(&ifv->ifv_if, m);
922 }
923