xref: /netbsd-src/sys/net/if_vlan.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: if_vlan.c,v 1.66 2010/04/05 07:22:24 joerg 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  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*
33  * Copyright 1998 Massachusetts Institute of Technology
34  *
35  * Permission to use, copy, modify, and distribute this software and
36  * its documentation for any purpose and without fee is hereby
37  * granted, provided that both the above copyright notice and this
38  * permission notice appear in all copies, that both the above
39  * copyright notice and this permission notice appear in all
40  * supporting documentation, and that the name of M.I.T. not be used
41  * in advertising or publicity pertaining to distribution of the
42  * software without specific, written prior permission.  M.I.T. makes
43  * no representations about the suitability of this software for any
44  * purpose.  It is provided "as is" without express or implied
45  * warranty.
46  *
47  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
48  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
49  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
50  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
51  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
52  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
53  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
54  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
55  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
56  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
57  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58  * SUCH DAMAGE.
59  *
60  * from FreeBSD: if_vlan.c,v 1.16 2000/03/26 15:21:40 charnier Exp
61  * via OpenBSD: if_vlan.c,v 1.4 2000/05/15 19:15:00 chris Exp
62  */
63 
64 /*
65  * if_vlan.c - pseudo-device driver for IEEE 802.1Q virtual LANs.  Might be
66  * extended some day to also handle IEEE 802.1P priority tagging.  This is
67  * sort of sneaky in the implementation, since we need to pretend to be
68  * enough of an Ethernet implementation to make ARP work.  The way we do
69  * this is by telling everyone that we are an Ethernet interface, and then
70  * catch the packets that ether_output() left on our output queue when it
71  * calls if_start(), rewrite them for use by the real outgoing interface,
72  * and ask it to send them.
73  *
74  * TODO:
75  *
76  *	- Need some way to notify vlan interfaces when the parent
77  *	  interface changes MTU.
78  */
79 
80 #include <sys/cdefs.h>
81 __KERNEL_RCSID(0, "$NetBSD: if_vlan.c,v 1.66 2010/04/05 07:22:24 joerg Exp $");
82 
83 #include "opt_inet.h"
84 
85 #include <sys/param.h>
86 #include <sys/kernel.h>
87 #include <sys/mbuf.h>
88 #include <sys/queue.h>
89 #include <sys/socket.h>
90 #include <sys/sockio.h>
91 #include <sys/systm.h>
92 #include <sys/proc.h>
93 #include <sys/kauth.h>
94 
95 #include <net/bpf.h>
96 #include <net/if.h>
97 #include <net/if_dl.h>
98 #include <net/if_types.h>
99 #include <net/if_ether.h>
100 #include <net/if_vlanvar.h>
101 
102 #ifdef INET
103 #include <netinet/in.h>
104 #include <netinet/if_inarp.h>
105 #endif
106 
107 struct vlan_mc_entry {
108 	LIST_ENTRY(vlan_mc_entry)	mc_entries;
109 	/*
110 	 * A key to identify this entry.  The mc_addr below can't be
111 	 * used since multiple sockaddr may mapped into the same
112 	 * ether_multi (e.g., AF_UNSPEC).
113 	 */
114 	union {
115 		struct ether_multi	*mcu_enm;
116 	} mc_u;
117 	struct sockaddr_storage		mc_addr;
118 };
119 
120 #define	mc_enm		mc_u.mcu_enm
121 
122 struct ifvlan {
123 	union {
124 		struct ethercom ifvu_ec;
125 	} ifv_u;
126 	struct ifnet *ifv_p;	/* parent interface of this vlan */
127 	struct ifv_linkmib {
128 		const struct vlan_multisw *ifvm_msw;
129 		int	ifvm_encaplen;	/* encapsulation length */
130 		int	ifvm_mtufudge;	/* MTU fudged by this much */
131 		int	ifvm_mintu;	/* min transmission unit */
132 		uint16_t ifvm_proto;	/* encapsulation ethertype */
133 		uint16_t ifvm_tag;	/* tag to apply on packets */
134 	} ifv_mib;
135 	LIST_HEAD(__vlan_mchead, vlan_mc_entry) ifv_mc_listhead;
136 	LIST_ENTRY(ifvlan) ifv_list;
137 	int ifv_flags;
138 };
139 
140 #define	IFVF_PROMISC	0x01		/* promiscuous mode enabled */
141 
142 #define	ifv_ec		ifv_u.ifvu_ec
143 
144 #define	ifv_if		ifv_ec.ec_if
145 
146 #define	ifv_msw		ifv_mib.ifvm_msw
147 #define	ifv_encaplen	ifv_mib.ifvm_encaplen
148 #define	ifv_mtufudge	ifv_mib.ifvm_mtufudge
149 #define	ifv_mintu	ifv_mib.ifvm_mintu
150 #define	ifv_tag		ifv_mib.ifvm_tag
151 
152 struct vlan_multisw {
153 	int	(*vmsw_addmulti)(struct ifvlan *, struct ifreq *);
154 	int	(*vmsw_delmulti)(struct ifvlan *, struct ifreq *);
155 	void	(*vmsw_purgemulti)(struct ifvlan *);
156 };
157 
158 static int	vlan_ether_addmulti(struct ifvlan *, struct ifreq *);
159 static int	vlan_ether_delmulti(struct ifvlan *, struct ifreq *);
160 static void	vlan_ether_purgemulti(struct ifvlan *);
161 
162 const struct vlan_multisw vlan_ether_multisw = {
163 	vlan_ether_addmulti,
164 	vlan_ether_delmulti,
165 	vlan_ether_purgemulti,
166 };
167 
168 static int	vlan_clone_create(struct if_clone *, int);
169 static int	vlan_clone_destroy(struct ifnet *);
170 static int	vlan_config(struct ifvlan *, struct ifnet *);
171 static int	vlan_ioctl(struct ifnet *, u_long, void *);
172 static void	vlan_start(struct ifnet *);
173 static void	vlan_unconfig(struct ifnet *);
174 
175 void		vlanattach(int);
176 
177 /* XXX This should be a hash table with the tag as the basis of the key. */
178 static LIST_HEAD(, ifvlan) ifv_list;
179 
180 struct if_clone vlan_cloner =
181     IF_CLONE_INITIALIZER("vlan", vlan_clone_create, vlan_clone_destroy);
182 
183 /* Used to pad ethernet frames with < ETHER_MIN_LEN bytes */
184 static char vlan_zero_pad_buff[ETHER_MIN_LEN];
185 
186 void
187 vlanattach(int n)
188 {
189 
190 	LIST_INIT(&ifv_list);
191 	if_clone_attach(&vlan_cloner);
192 }
193 
194 static void
195 vlan_reset_linkname(struct ifnet *ifp)
196 {
197 
198 	/*
199 	 * We start out with a "802.1Q VLAN" type and zero-length
200 	 * addresses.  When we attach to a parent interface, we
201 	 * inherit its type, address length, address, and data link
202 	 * type.
203 	 */
204 
205 	ifp->if_type = IFT_L2VLAN;
206 	ifp->if_addrlen = 0;
207 	ifp->if_dlt = DLT_NULL;
208 	if_alloc_sadl(ifp);
209 }
210 
211 static int
212 vlan_clone_create(struct if_clone *ifc, int unit)
213 {
214 	struct ifvlan *ifv;
215 	struct ifnet *ifp;
216 	int s;
217 
218 	ifv = malloc(sizeof(struct ifvlan), M_DEVBUF, M_WAITOK|M_ZERO);
219 	ifp = &ifv->ifv_if;
220 	LIST_INIT(&ifv->ifv_mc_listhead);
221 
222 	s = splnet();
223 	LIST_INSERT_HEAD(&ifv_list, ifv, ifv_list);
224 	splx(s);
225 
226 	if_initname(ifp, ifc->ifc_name, unit);
227 	ifp->if_softc = ifv;
228 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
229 	ifp->if_start = vlan_start;
230 	ifp->if_ioctl = vlan_ioctl;
231 	IFQ_SET_READY(&ifp->if_snd);
232 
233 	if_attach(ifp);
234 	vlan_reset_linkname(ifp);
235 
236 	return (0);
237 }
238 
239 static int
240 vlan_clone_destroy(struct ifnet *ifp)
241 {
242 	struct ifvlan *ifv = ifp->if_softc;
243 	int s;
244 
245 	s = splnet();
246 	LIST_REMOVE(ifv, ifv_list);
247 	vlan_unconfig(ifp);
248 	splx(s);
249 
250 	if_detach(ifp);
251 	free(ifv, M_DEVBUF);
252 
253 	return (0);
254 }
255 
256 /*
257  * Configure a VLAN interface.  Must be called at splnet().
258  */
259 static int
260 vlan_config(struct ifvlan *ifv, struct ifnet *p)
261 {
262 	struct ifnet *ifp = &ifv->ifv_if;
263 	int error;
264 
265 	if (ifv->ifv_p != NULL)
266 		return (EBUSY);
267 
268 	switch (p->if_type) {
269 	case IFT_ETHER:
270 	    {
271 		struct ethercom *ec = (void *) p;
272 
273 		ifv->ifv_msw = &vlan_ether_multisw;
274 		ifv->ifv_encaplen = ETHER_VLAN_ENCAP_LEN;
275 		ifv->ifv_mintu = ETHERMIN;
276 
277 		/*
278 		 * If the parent supports the VLAN_MTU capability,
279 		 * i.e. can Tx/Rx larger than ETHER_MAX_LEN frames,
280 		 * enable it.
281 		 */
282 		if (ec->ec_nvlans++ == 0 &&
283 		    (ec->ec_capabilities & ETHERCAP_VLAN_MTU) != 0) {
284 			/*
285 			 * Enable Tx/Rx of VLAN-sized frames.
286 			 */
287 			ec->ec_capenable |= ETHERCAP_VLAN_MTU;
288 			if (p->if_flags & IFF_UP) {
289 				struct ifreq ifr;
290 
291 				ifr.ifr_flags = p->if_flags;
292 				error = (*p->if_ioctl)(p, SIOCSIFFLAGS,
293 				    (void *) &ifr);
294 				if (error) {
295 					if (ec->ec_nvlans-- == 1)
296 						ec->ec_capenable &=
297 						    ~ETHERCAP_VLAN_MTU;
298 					return (error);
299 				}
300 			}
301 			ifv->ifv_mtufudge = 0;
302 		} else if ((ec->ec_capabilities & ETHERCAP_VLAN_MTU) == 0) {
303 			/*
304 			 * Fudge the MTU by the encapsulation size.  This
305 			 * makes us incompatible with strictly compliant
306 			 * 802.1Q implementations, but allows us to use
307 			 * the feature with other NetBSD implementations,
308 			 * which might still be useful.
309 			 */
310 			ifv->ifv_mtufudge = ifv->ifv_encaplen;
311 		}
312 
313 		/*
314 		 * If the parent interface can do hardware-assisted
315 		 * VLAN encapsulation, then propagate its hardware-
316 		 * assisted checksumming flags and tcp segmentation
317 		 * offload.
318 		 */
319 		if (ec->ec_capabilities & ETHERCAP_VLAN_HWTAGGING)
320 			ifp->if_capabilities = p->if_capabilities &
321 			    (IFCAP_TSOv4 | IFCAP_TSOv6 |
322 			     IFCAP_CSUM_IPv4_Tx|IFCAP_CSUM_IPv4_Rx|
323 			     IFCAP_CSUM_TCPv4_Tx|IFCAP_CSUM_TCPv4_Rx|
324 			     IFCAP_CSUM_UDPv4_Tx|IFCAP_CSUM_UDPv4_Rx|
325 			     IFCAP_CSUM_TCPv6_Tx|IFCAP_CSUM_TCPv6_Rx|
326 			     IFCAP_CSUM_UDPv6_Tx|IFCAP_CSUM_UDPv6_Rx);
327 
328 		/*
329 		 * We inherit the parent's Ethernet address.
330 		 */
331 		ether_ifattach(ifp, CLLADDR(p->if_sadl));
332 		ifp->if_hdrlen = sizeof(struct ether_vlan_header); /* XXX? */
333 		break;
334 	    }
335 
336 	default:
337 		return (EPROTONOSUPPORT);
338 	}
339 
340 	ifv->ifv_p = p;
341 	ifv->ifv_if.if_mtu = p->if_mtu - ifv->ifv_mtufudge;
342 	ifv->ifv_if.if_flags = p->if_flags &
343 	    (IFF_UP | IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
344 
345 	/*
346 	 * Inherit the if_type from the parent.  This allows us
347 	 * to participate in bridges of that type.
348 	 */
349 	ifv->ifv_if.if_type = p->if_type;
350 
351 	return (0);
352 }
353 
354 /*
355  * Unconfigure a VLAN interface.  Must be called at splnet().
356  */
357 static void
358 vlan_unconfig(struct ifnet *ifp)
359 {
360 	struct ifvlan *ifv = ifp->if_softc;
361 
362 	if (ifv->ifv_p == NULL)
363 		return;
364 
365 	/*
366  	 * Since the interface is being unconfigured, we need to empty the
367 	 * list of multicast groups that we may have joined while we were
368 	 * alive and remove them from the parent's list also.
369 	 */
370 	(*ifv->ifv_msw->vmsw_purgemulti)(ifv);
371 
372 	/* Disconnect from parent. */
373 	switch (ifv->ifv_p->if_type) {
374 	case IFT_ETHER:
375 	    {
376 		struct ethercom *ec = (void *) ifv->ifv_p;
377 
378 		if (ec->ec_nvlans-- == 1) {
379 			/*
380 			 * Disable Tx/Rx of VLAN-sized frames.
381 			 */
382 			ec->ec_capenable &= ~ETHERCAP_VLAN_MTU;
383 			if (ifv->ifv_p->if_flags & IFF_UP) {
384 				struct ifreq ifr;
385 
386 				ifr.ifr_flags = ifv->ifv_p->if_flags;
387 				(void) (*ifv->ifv_p->if_ioctl)(ifv->ifv_p,
388 				    SIOCSIFFLAGS, (void *) &ifr);
389 			}
390 		}
391 
392 		ether_ifdetach(ifp);
393 		vlan_reset_linkname(ifp);
394 		break;
395 	    }
396 
397 #ifdef DIAGNOSTIC
398 	default:
399 		panic("vlan_unconfig: impossible");
400 #endif
401 	}
402 
403 	ifv->ifv_p = NULL;
404 	ifv->ifv_if.if_mtu = 0;
405 	ifv->ifv_flags = 0;
406 
407 	if_down(ifp);
408 	ifp->if_flags &= ~(IFF_UP|IFF_RUNNING);
409 	ifp->if_capabilities = 0;
410 }
411 
412 /*
413  * Called when a parent interface is detaching; destroy any VLAN
414  * configuration for the parent interface.
415  */
416 void
417 vlan_ifdetach(struct ifnet *p)
418 {
419 	struct ifvlan *ifv;
420 	int s;
421 
422 	s = splnet();
423 
424 	for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
425 	     ifv = LIST_NEXT(ifv, ifv_list)) {
426 		if (ifv->ifv_p == p)
427 			vlan_unconfig(&ifv->ifv_if);
428 	}
429 
430 	splx(s);
431 }
432 
433 static int
434 vlan_set_promisc(struct ifnet *ifp)
435 {
436 	struct ifvlan *ifv = ifp->if_softc;
437 	int error = 0;
438 
439 	if ((ifp->if_flags & IFF_PROMISC) != 0) {
440 		if ((ifv->ifv_flags & IFVF_PROMISC) == 0) {
441 			error = ifpromisc(ifv->ifv_p, 1);
442 			if (error == 0)
443 				ifv->ifv_flags |= IFVF_PROMISC;
444 		}
445 	} else {
446 		if ((ifv->ifv_flags & IFVF_PROMISC) != 0) {
447 			error = ifpromisc(ifv->ifv_p, 0);
448 			if (error == 0)
449 				ifv->ifv_flags &= ~IFVF_PROMISC;
450 		}
451 	}
452 
453 	return (error);
454 }
455 
456 static int
457 vlan_ioctl(struct ifnet *ifp, u_long cmd, void *data)
458 {
459 	struct lwp *l = curlwp;	/* XXX */
460 	struct ifvlan *ifv = ifp->if_softc;
461 	struct ifaddr *ifa = (struct ifaddr *) data;
462 	struct ifreq *ifr = (struct ifreq *) data;
463 	struct ifnet *pr;
464 	struct ifcapreq *ifcr;
465 	struct vlanreq vlr;
466 	int s, error = 0;
467 
468 	s = splnet();
469 
470 	switch (cmd) {
471 	case SIOCINITIFADDR:
472 		if (ifv->ifv_p != NULL) {
473 			ifp->if_flags |= IFF_UP;
474 
475 			switch (ifa->ifa_addr->sa_family) {
476 #ifdef INET
477 			case AF_INET:
478 				arp_ifinit(ifp, ifa);
479 				break;
480 #endif
481 			default:
482 				break;
483 			}
484 		} else {
485 			error = EINVAL;
486 		}
487 		break;
488 
489 	case SIOCSIFMTU:
490 		if (ifv->ifv_p == NULL)
491 			error = EINVAL;
492 		else if (
493 		    ifr->ifr_mtu > (ifv->ifv_p->if_mtu - ifv->ifv_mtufudge) ||
494 		    ifr->ifr_mtu < (ifv->ifv_mintu - ifv->ifv_mtufudge))
495 			error = EINVAL;
496 		else if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
497 			error = 0;
498 		break;
499 
500 	case SIOCSETVLAN:
501 		if ((error = kauth_authorize_network(l->l_cred,
502 		    KAUTH_NETWORK_INTERFACE,
503 		    KAUTH_REQ_NETWORK_INTERFACE_SETPRIV, ifp, (void *)cmd,
504 		    NULL)) != 0)
505 			break;
506 		if ((error = copyin(ifr->ifr_data, &vlr, sizeof(vlr))) != 0)
507 			break;
508 		if (vlr.vlr_parent[0] == '\0') {
509 			vlan_unconfig(ifp);
510 			break;
511 		}
512 		if (vlr.vlr_tag != EVL_VLANOFTAG(vlr.vlr_tag)) {
513 			error = EINVAL;		 /* check for valid tag */
514 			break;
515 		}
516 		if ((pr = ifunit(vlr.vlr_parent)) == 0) {
517 			error = ENOENT;
518 			break;
519 		}
520 		if ((error = vlan_config(ifv, pr)) != 0)
521 			break;
522 		ifv->ifv_tag = vlr.vlr_tag;
523 		ifp->if_flags |= IFF_RUNNING;
524 
525 		/* Update promiscuous mode, if necessary. */
526 		vlan_set_promisc(ifp);
527 		break;
528 
529 	case SIOCGETVLAN:
530 		memset(&vlr, 0, sizeof(vlr));
531 		if (ifv->ifv_p != NULL) {
532 			snprintf(vlr.vlr_parent, sizeof(vlr.vlr_parent), "%s",
533 			    ifv->ifv_p->if_xname);
534 			vlr.vlr_tag = ifv->ifv_tag;
535 		}
536 		error = copyout(&vlr, ifr->ifr_data, sizeof(vlr));
537 		break;
538 
539 	case SIOCSIFFLAGS:
540 		if ((error = ifioctl_common(ifp, cmd, data)) != 0)
541 			break;
542 		/*
543 		 * For promiscuous mode, we enable promiscuous mode on
544 		 * the parent if we need promiscuous on the VLAN interface.
545 		 */
546 		if (ifv->ifv_p != NULL)
547 			error = vlan_set_promisc(ifp);
548 		break;
549 
550 	case SIOCADDMULTI:
551 		error = (ifv->ifv_p != NULL) ?
552 		    (*ifv->ifv_msw->vmsw_addmulti)(ifv, ifr) : EINVAL;
553 		break;
554 
555 	case SIOCDELMULTI:
556 		error = (ifv->ifv_p != NULL) ?
557 		    (*ifv->ifv_msw->vmsw_delmulti)(ifv, ifr) : EINVAL;
558 		break;
559 
560 	case SIOCSIFCAP:
561 		ifcr = data;
562 		/* make sure caps are enabled on parent */
563 		if ((ifv->ifv_p->if_capenable & ifcr->ifcr_capenable) !=
564 		    ifcr->ifcr_capenable) {
565 			error = EINVAL;
566 			break;
567 		}
568 		if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
569 			error = 0;
570 		break;
571 	default:
572 		error = ether_ioctl(ifp, cmd, data);
573 	}
574 
575 	splx(s);
576 
577 	return (error);
578 }
579 
580 static int
581 vlan_ether_addmulti(struct ifvlan *ifv, struct ifreq *ifr)
582 {
583 	const struct sockaddr *sa = ifreq_getaddr(SIOCADDMULTI, ifr);
584 	struct vlan_mc_entry *mc;
585 	uint8_t addrlo[ETHER_ADDR_LEN], addrhi[ETHER_ADDR_LEN];
586 	int error;
587 
588 	if (sa->sa_len > sizeof(struct sockaddr_storage))
589 		return (EINVAL);
590 
591 	error = ether_addmulti(sa, &ifv->ifv_ec);
592 	if (error != ENETRESET)
593 		return (error);
594 
595 	/*
596 	 * This is new multicast address.  We have to tell parent
597 	 * about it.  Also, remember this multicast address so that
598 	 * we can delete them on unconfigure.
599 	 */
600 	mc = malloc(sizeof(struct vlan_mc_entry), M_DEVBUF, M_NOWAIT);
601 	if (mc == NULL) {
602 		error = ENOMEM;
603 		goto alloc_failed;
604 	}
605 
606 	/*
607 	 * As ether_addmulti() returns ENETRESET, following two
608 	 * statement shouldn't fail.
609 	 */
610 	(void)ether_multiaddr(sa, addrlo, addrhi);
611 	ETHER_LOOKUP_MULTI(addrlo, addrhi, &ifv->ifv_ec, mc->mc_enm);
612 	memcpy(&mc->mc_addr, sa, sa->sa_len);
613 	LIST_INSERT_HEAD(&ifv->ifv_mc_listhead, mc, mc_entries);
614 
615 	error = (*ifv->ifv_p->if_ioctl)(ifv->ifv_p, SIOCADDMULTI,
616 	    (void *)ifr);
617 	if (error != 0)
618 		goto ioctl_failed;
619 	return (error);
620 
621  ioctl_failed:
622 	LIST_REMOVE(mc, mc_entries);
623 	free(mc, M_DEVBUF);
624  alloc_failed:
625 	(void)ether_delmulti(sa, &ifv->ifv_ec);
626 	return (error);
627 }
628 
629 static int
630 vlan_ether_delmulti(struct ifvlan *ifv, struct ifreq *ifr)
631 {
632 	const struct sockaddr *sa = ifreq_getaddr(SIOCDELMULTI, ifr);
633 	struct ether_multi *enm;
634 	struct vlan_mc_entry *mc;
635 	uint8_t addrlo[ETHER_ADDR_LEN], addrhi[ETHER_ADDR_LEN];
636 	int error;
637 
638 	/*
639 	 * Find a key to lookup vlan_mc_entry.  We have to do this
640 	 * before calling ether_delmulti for obvious reason.
641 	 */
642 	if ((error = ether_multiaddr(sa, addrlo, addrhi)) != 0)
643 		return (error);
644 	ETHER_LOOKUP_MULTI(addrlo, addrhi, &ifv->ifv_ec, enm);
645 
646 	error = ether_delmulti(sa, &ifv->ifv_ec);
647 	if (error != ENETRESET)
648 		return (error);
649 
650 	/* We no longer use this multicast address.  Tell parent so. */
651 	error = (*ifv->ifv_p->if_ioctl)(ifv->ifv_p, SIOCDELMULTI,
652 	    (void *)ifr);
653 	if (error == 0) {
654 		/* And forget about this address. */
655 		for (mc = LIST_FIRST(&ifv->ifv_mc_listhead); mc != NULL;
656 		    mc = LIST_NEXT(mc, mc_entries)) {
657 			if (mc->mc_enm == enm) {
658 				LIST_REMOVE(mc, mc_entries);
659 				free(mc, M_DEVBUF);
660 				break;
661 			}
662 		}
663 		KASSERT(mc != NULL);
664 	} else
665 		(void)ether_addmulti(sa, &ifv->ifv_ec);
666 	return (error);
667 }
668 
669 /*
670  * Delete any multicast address we have asked to add from parent
671  * interface.  Called when the vlan is being unconfigured.
672  */
673 static void
674 vlan_ether_purgemulti(struct ifvlan *ifv)
675 {
676 	struct ifnet *ifp = ifv->ifv_p;		/* Parent. */
677 	struct vlan_mc_entry *mc;
678 	union {
679 		struct ifreq ifreq;
680 		struct {
681 			char ifr_name[IFNAMSIZ];
682 			struct sockaddr_storage ifr_ss;
683 		} ifreq_storage;
684 	} ifreq;
685 	struct ifreq *ifr = &ifreq.ifreq;
686 
687 	memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ);
688 	while ((mc = LIST_FIRST(&ifv->ifv_mc_listhead)) != NULL) {
689 		ifreq_setaddr(SIOCDELMULTI, ifr,
690 		    (const struct sockaddr *)&mc->mc_addr);
691 		(void)(*ifp->if_ioctl)(ifp, SIOCDELMULTI, (void *)ifr);
692 		LIST_REMOVE(mc, mc_entries);
693 		free(mc, M_DEVBUF);
694 	}
695 }
696 
697 static void
698 vlan_start(struct ifnet *ifp)
699 {
700 	struct ifvlan *ifv = ifp->if_softc;
701 	struct ifnet *p = ifv->ifv_p;
702 	struct ethercom *ec = (void *) ifv->ifv_p;
703 	struct mbuf *m;
704 	int error;
705 	ALTQ_DECL(struct altq_pktattr pktattr;)
706 
707 	ifp->if_flags |= IFF_OACTIVE;
708 
709 	for (;;) {
710 		IFQ_DEQUEUE(&ifp->if_snd, m);
711 		if (m == NULL)
712 			break;
713 
714 #ifdef ALTQ
715 		/*
716 		 * If ALTQ is enabled on the parent interface, do
717 		 * classification; the queueing discipline might
718 		 * not require classification, but might require
719 		 * the address family/header pointer in the pktattr.
720 		 */
721 		if (ALTQ_IS_ENABLED(&p->if_snd)) {
722 			switch (p->if_type) {
723 			case IFT_ETHER:
724 				altq_etherclassify(&p->if_snd, m, &pktattr);
725 				break;
726 #ifdef DIAGNOSTIC
727 			default:
728 				panic("vlan_start: impossible (altq)");
729 #endif
730 			}
731 		}
732 #endif /* ALTQ */
733 
734 		bpf_mtap(ifp, m);
735 		/*
736 		 * If the parent can insert the tag itself, just mark
737 		 * the tag in the mbuf header.
738 		 */
739 		if (ec->ec_capabilities & ETHERCAP_VLAN_HWTAGGING) {
740 			struct m_tag *mtag;
741 
742 			mtag = m_tag_get(PACKET_TAG_VLAN, sizeof(u_int),
743 			    M_NOWAIT);
744 			if (mtag == NULL) {
745 				ifp->if_oerrors++;
746 				m_freem(m);
747 				continue;
748 			}
749 			*(u_int *)(mtag + 1) = ifv->ifv_tag;
750 			m_tag_prepend(m, mtag);
751 		} else {
752 			/*
753 			 * insert the tag ourselves
754 			 */
755 			M_PREPEND(m, ifv->ifv_encaplen, M_DONTWAIT);
756 			if (m == NULL) {
757 				printf("%s: unable to prepend encap header",
758 				    ifv->ifv_p->if_xname);
759 				ifp->if_oerrors++;
760 				continue;
761 			}
762 
763 			switch (p->if_type) {
764 			case IFT_ETHER:
765 			    {
766 				struct ether_vlan_header *evl;
767 
768 				if (m->m_len < sizeof(struct ether_vlan_header))
769 					m = m_pullup(m,
770 					    sizeof(struct ether_vlan_header));
771 				if (m == NULL) {
772 					printf("%s: unable to pullup encap "
773 					    "header", ifv->ifv_p->if_xname);
774 					ifp->if_oerrors++;
775 					continue;
776 				}
777 
778 				/*
779 				 * Transform the Ethernet header into an
780 				 * Ethernet header with 802.1Q encapsulation.
781 				 */
782 				memmove(mtod(m, void *),
783 				    mtod(m, char *) + ifv->ifv_encaplen,
784 				    sizeof(struct ether_header));
785 				evl = mtod(m, struct ether_vlan_header *);
786 				evl->evl_proto = evl->evl_encap_proto;
787 				evl->evl_encap_proto = htons(ETHERTYPE_VLAN);
788 				evl->evl_tag = htons(ifv->ifv_tag);
789 
790 				/*
791 				 * To cater for VLAN-aware layer 2 ethernet
792 				 * switches which may need to strip the tag
793 				 * before forwarding the packet, make sure
794 				 * the packet+tag is at least 68 bytes long.
795 				 * This is necessary because our parent will
796 				 * only pad to 64 bytes (ETHER_MIN_LEN) and
797 				 * some switches will not pad by themselves
798 				 * after deleting a tag.
799 				 */
800 				if (m->m_pkthdr.len <
801 				    (ETHER_MIN_LEN + ETHER_VLAN_ENCAP_LEN)) {
802 					m_copyback(m, m->m_pkthdr.len,
803 					    (ETHER_MIN_LEN +
804 					     ETHER_VLAN_ENCAP_LEN) -
805 					     m->m_pkthdr.len,
806 					    vlan_zero_pad_buff);
807 				}
808 				break;
809 			    }
810 
811 #ifdef DIAGNOSTIC
812 			default:
813 				panic("vlan_start: impossible");
814 #endif
815 			}
816 		}
817 
818 		/*
819 		 * Send it, precisely as the parent's output routine
820 		 * would have.  We are already running at splnet.
821 		 */
822 		IFQ_ENQUEUE(&p->if_snd, m, &pktattr, error);
823 		if (error) {
824 			/* mbuf is already freed */
825 			ifp->if_oerrors++;
826 			continue;
827 		}
828 
829 		ifp->if_opackets++;
830 		if ((p->if_flags & (IFF_RUNNING|IFF_OACTIVE)) == IFF_RUNNING)
831 			(*p->if_start)(p);
832 	}
833 
834 	ifp->if_flags &= ~IFF_OACTIVE;
835 }
836 
837 /*
838  * Given an Ethernet frame, find a valid vlan interface corresponding to the
839  * given source interface and tag, then run the real packet through the
840  * parent's input routine.
841  */
842 void
843 vlan_input(struct ifnet *ifp, struct mbuf *m)
844 {
845 	struct ifvlan *ifv;
846 	u_int tag;
847 	struct m_tag *mtag;
848 
849 	mtag = m_tag_find(m, PACKET_TAG_VLAN, NULL);
850 	if (mtag != NULL) {
851 		/* m contains a normal ethernet frame, the tag is in mtag */
852 		tag = EVL_VLANOFTAG(*(u_int *)(mtag + 1));
853 		m_tag_delete(m, mtag);
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 
889 	for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
890 	    ifv = LIST_NEXT(ifv, ifv_list))
891 		if (ifp == ifv->ifv_p && tag == ifv->ifv_tag)
892 			break;
893 
894 	if (ifv == NULL ||
895 	    (ifv->ifv_if.if_flags & (IFF_UP|IFF_RUNNING)) !=
896 	     (IFF_UP|IFF_RUNNING)) {
897 		m_freem(m);
898 		ifp->if_noproto++;
899 		return;
900 	}
901 
902 	/*
903 	 * Now, remove the encapsulation header.  The original
904 	 * header has already been fixed up above.
905 	 */
906 	if (mtag == NULL) {
907 		memmove(mtod(m, char *) + ifv->ifv_encaplen,
908 		    mtod(m, void *), sizeof(struct ether_header));
909 		m_adj(m, ifv->ifv_encaplen);
910 	}
911 
912 	m->m_pkthdr.rcvif = &ifv->ifv_if;
913 	ifv->ifv_if.if_ipackets++;
914 
915 	bpf_mtap(&ifv->ifv_if, m);
916 
917 	/* Pass it back through the parent's input routine. */
918 	(*ifp->if_input)(&ifv->ifv_if, m);
919 }
920