xref: /netbsd-src/sys/net/if_vlan.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: if_vlan.c,v 1.47 2005/12/11 12:24:51 christos 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 1.47 2005/12/11 12:24:51 christos 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 int	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 	snprintf(ifp->if_xname, sizeof(ifp->if_xname), "%s%d", ifc->ifc_name,
237 	    unit);
238 	ifp->if_softc = ifv;
239 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
240 	ifp->if_start = vlan_start;
241 	ifp->if_ioctl = vlan_ioctl;
242 	IFQ_SET_READY(&ifp->if_snd);
243 
244 	if_attach(ifp);
245 	vlan_reset_linkname(ifp);
246 
247 	return (0);
248 }
249 
250 static int
251 vlan_clone_destroy(struct ifnet *ifp)
252 {
253 	struct ifvlan *ifv = ifp->if_softc;
254 	int s;
255 
256 	s = splnet();
257 	LIST_REMOVE(ifv, ifv_list);
258 	vlan_unconfig(ifp);
259 	splx(s);
260 
261 	if_detach(ifp);
262 	free(ifv, M_DEVBUF);
263 
264 	return (0);
265 }
266 
267 /*
268  * Configure a VLAN interface.  Must be called at splnet().
269  */
270 static int
271 vlan_config(struct ifvlan *ifv, struct ifnet *p)
272 {
273 	struct ifnet *ifp = &ifv->ifv_if;
274 	int error;
275 
276 	if (ifv->ifv_p != NULL)
277 		return (EBUSY);
278 
279 	switch (p->if_type) {
280 	case IFT_ETHER:
281 	    {
282 		struct ethercom *ec = (void *) p;
283 
284 		ifv->ifv_msw = &vlan_ether_multisw;
285 		ifv->ifv_encaplen = ETHER_VLAN_ENCAP_LEN;
286 		ifv->ifv_mintu = ETHERMIN;
287 
288 		/*
289 		 * If the parent supports the VLAN_MTU capability,
290 		 * i.e. can Tx/Rx larger than ETHER_MAX_LEN frames,
291 		 * enable it.
292 		 */
293 		if (ec->ec_nvlans++ == 0 &&
294 		    (ec->ec_capabilities & ETHERCAP_VLAN_MTU) != 0) {
295 			/*
296 			 * Enable Tx/Rx of VLAN-sized frames.
297 			 */
298 			ec->ec_capenable |= ETHERCAP_VLAN_MTU;
299 			if (p->if_flags & IFF_UP) {
300 				struct ifreq ifr;
301 
302 				ifr.ifr_flags = p->if_flags;
303 				error = (*p->if_ioctl)(p, SIOCSIFFLAGS,
304 				    (caddr_t) &ifr);
305 				if (error) {
306 					if (ec->ec_nvlans-- == 1)
307 						ec->ec_capenable &=
308 						    ~ETHERCAP_VLAN_MTU;
309 					return (error);
310 				}
311 			}
312 			ifv->ifv_mtufudge = 0;
313 		} else if ((ec->ec_capabilities & ETHERCAP_VLAN_MTU) == 0) {
314 			/*
315 			 * Fudge the MTU by the encapsulation size.  This
316 			 * makes us incompatible with strictly compliant
317 			 * 802.1Q implementations, but allows us to use
318 			 * the feature with other NetBSD implementations,
319 			 * which might still be useful.
320 			 */
321 			ifv->ifv_mtufudge = ifv->ifv_encaplen;
322 		}
323 
324 		/*
325 		 * If the parent interface can do hardware-assisted
326 		 * VLAN encapsulation, then propagate its hardware-
327 		 * assisted checksumming flags.
328 		 */
329 		if (ec->ec_capabilities & ETHERCAP_VLAN_HWTAGGING)
330 			ifp->if_capabilities = p->if_capabilities &
331 			    (IFCAP_CSUM_IPv4_Tx|IFCAP_CSUM_IPv4_Rx|
332 			     IFCAP_CSUM_TCPv4_Tx|IFCAP_CSUM_TCPv4_Rx|
333 			     IFCAP_CSUM_UDPv4_Tx|IFCAP_CSUM_UDPv4_Rx|
334 			     IFCAP_CSUM_TCPv6_Tx|IFCAP_CSUM_TCPv6_Rx|
335 			     IFCAP_CSUM_UDPv6_Tx|IFCAP_CSUM_UDPv6_Rx);
336 
337 		/*
338 		 * We inherit the parent's Ethernet address.
339 		 */
340 		ether_ifattach(ifp, LLADDR(p->if_sadl));
341 		ifp->if_hdrlen = sizeof(struct ether_vlan_header); /* XXX? */
342 		break;
343 	    }
344 
345 	default:
346 		return (EPROTONOSUPPORT);
347 	}
348 
349 	ifv->ifv_p = p;
350 	ifv->ifv_if.if_mtu = p->if_mtu - ifv->ifv_mtufudge;
351 	ifv->ifv_if.if_flags = p->if_flags &
352 	    (IFF_UP | IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
353 
354 	/*
355 	 * Inherit the if_type from the parent.  This allows us
356 	 * to participate in bridges of that type.
357 	 */
358 	ifv->ifv_if.if_type = p->if_type;
359 
360 	return (0);
361 }
362 
363 /*
364  * Unconfigure a VLAN interface.  Must be called at splnet().
365  */
366 static void
367 vlan_unconfig(struct ifnet *ifp)
368 {
369 	struct ifvlan *ifv = ifp->if_softc;
370 
371 	if (ifv->ifv_p == NULL)
372 		return;
373 
374 	/*
375  	 * Since the interface is being unconfigured, we need to empty the
376 	 * list of multicast groups that we may have joined while we were
377 	 * alive and remove them from the parent's list also.
378 	 */
379 	(*ifv->ifv_msw->vmsw_purgemulti)(ifv);
380 
381 	/* Disconnect from parent. */
382 	switch (ifv->ifv_p->if_type) {
383 	case IFT_ETHER:
384 	    {
385 		struct ethercom *ec = (void *) ifv->ifv_p;
386 
387 		if (ec->ec_nvlans-- == 1) {
388 			/*
389 			 * Disable Tx/Rx of VLAN-sized frames.
390 			 */
391 			ec->ec_capenable &= ~ETHERCAP_VLAN_MTU;
392 			if (ifv->ifv_p->if_flags & IFF_UP) {
393 				struct ifreq ifr;
394 
395 				ifr.ifr_flags = ifv->ifv_p->if_flags;
396 				(void) (*ifv->ifv_p->if_ioctl)(ifv->ifv_p,
397 				    SIOCSIFFLAGS, (caddr_t) &ifr);
398 			}
399 		}
400 
401 		ether_ifdetach(ifp);
402 		vlan_reset_linkname(ifp);
403 		break;
404 	    }
405 
406 #ifdef DIAGNOSTIC
407 	default:
408 		panic("vlan_unconfig: impossible");
409 #endif
410 	}
411 
412 	ifv->ifv_p = NULL;
413 	ifv->ifv_if.if_mtu = 0;
414 	ifv->ifv_flags = 0;
415 
416 	if_down(ifp);
417 	ifp->if_flags &= ~(IFF_UP|IFF_RUNNING);
418 	ifp->if_capabilities = 0;
419 }
420 
421 /*
422  * Called when a parent interface is detaching; destroy any VLAN
423  * configuration for the parent interface.
424  */
425 void
426 vlan_ifdetach(struct ifnet *p)
427 {
428 	struct ifvlan *ifv;
429 	int s;
430 
431 	s = splnet();
432 
433 	for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
434 	     ifv = LIST_NEXT(ifv, ifv_list)) {
435 		if (ifv->ifv_p == p)
436 			vlan_unconfig(&ifv->ifv_if);
437 	}
438 
439 	splx(s);
440 }
441 
442 static int
443 vlan_set_promisc(struct ifnet *ifp)
444 {
445 	struct ifvlan *ifv = ifp->if_softc;
446 	int error = 0;
447 
448 	if ((ifp->if_flags & IFF_PROMISC) != 0) {
449 		if ((ifv->ifv_flags & IFVF_PROMISC) == 0) {
450 			error = ifpromisc(ifv->ifv_p, 1);
451 			if (error == 0)
452 				ifv->ifv_flags |= IFVF_PROMISC;
453 		}
454 	} else {
455 		if ((ifv->ifv_flags & IFVF_PROMISC) != 0) {
456 			error = ifpromisc(ifv->ifv_p, 0);
457 			if (error == 0)
458 				ifv->ifv_flags &= ~IFVF_PROMISC;
459 		}
460 	}
461 
462 	return (error);
463 }
464 
465 static int
466 vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
467 {
468 	struct proc *p = curproc;	/* XXX */
469 	struct ifvlan *ifv = ifp->if_softc;
470 	struct ifaddr *ifa = (struct ifaddr *) data;
471 	struct ifreq *ifr = (struct ifreq *) data;
472 	struct ifnet *pr;
473 	struct vlanreq vlr;
474 	struct sockaddr *sa;
475 	int s, error = 0;
476 
477 	s = splnet();
478 
479 	switch (cmd) {
480 	case SIOCSIFADDR:
481 		if (ifv->ifv_p != NULL) {
482 			ifp->if_flags |= IFF_UP;
483 
484 			switch (ifa->ifa_addr->sa_family) {
485 #ifdef INET
486 			case AF_INET:
487 				arp_ifinit(ifp, ifa);
488 				break;
489 #endif
490 			default:
491 				break;
492 			}
493 		} else {
494 			error = EINVAL;
495 		}
496 		break;
497 
498 	case SIOCGIFADDR:
499 		sa = (struct sockaddr *)&ifr->ifr_data;
500 		memcpy(sa->sa_data, LLADDR(ifp->if_sadl), ifp->if_addrlen);
501 		break;
502 
503 	case SIOCSIFMTU:
504 		if (ifv->ifv_p != NULL) {
505 			if (ifr->ifr_mtu >
506 			     (ifv->ifv_p->if_mtu - ifv->ifv_mtufudge) ||
507 			    ifr->ifr_mtu <
508 			     (ifv->ifv_mintu - ifv->ifv_mtufudge))
509 				error = EINVAL;
510 			else
511 				ifp->if_mtu = ifr->ifr_mtu;
512 		} else
513 			error = EINVAL;
514 		break;
515 
516 	case SIOCSETVLAN:
517 		if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
518 			break;
519 		if ((error = copyin(ifr->ifr_data, &vlr, sizeof(vlr))) != 0)
520 			break;
521 		if (vlr.vlr_parent[0] == '\0') {
522 			vlan_unconfig(ifp);
523 			break;
524 		}
525 		if (vlr.vlr_tag != EVL_VLANOFTAG(vlr.vlr_tag)) {
526 			error = EINVAL;		 /* check for valid tag */
527 			break;
528 		}
529 		if ((pr = ifunit(vlr.vlr_parent)) == 0) {
530 			error = ENOENT;
531 			break;
532 		}
533 		if ((error = vlan_config(ifv, pr)) != 0)
534 			break;
535 		ifv->ifv_tag = vlr.vlr_tag;
536 		ifp->if_flags |= IFF_RUNNING;
537 
538 		/* Update promiscuous mode, if necessary. */
539 		vlan_set_promisc(ifp);
540 		break;
541 
542 	case SIOCGETVLAN:
543 		memset(&vlr, 0, sizeof(vlr));
544 		if (ifv->ifv_p != NULL) {
545 			snprintf(vlr.vlr_parent, sizeof(vlr.vlr_parent), "%s",
546 			    ifv->ifv_p->if_xname);
547 			vlr.vlr_tag = ifv->ifv_tag;
548 		}
549 		error = copyout(&vlr, ifr->ifr_data, sizeof(vlr));
550 		break;
551 
552 	case SIOCSIFFLAGS:
553 		/*
554 		 * For promiscuous mode, we enable promiscuous mode on
555 		 * the parent if we need promiscuous on the VLAN interface.
556 		 */
557 		if (ifv->ifv_p != NULL)
558 			error = vlan_set_promisc(ifp);
559 		break;
560 
561 	case SIOCADDMULTI:
562 		error = (ifv->ifv_p != NULL) ?
563 		    (*ifv->ifv_msw->vmsw_addmulti)(ifv, ifr) : EINVAL;
564 		break;
565 
566 	case SIOCDELMULTI:
567 		error = (ifv->ifv_p != NULL) ?
568 		    (*ifv->ifv_msw->vmsw_delmulti)(ifv, ifr) : EINVAL;
569 		break;
570 
571 	default:
572 		error = EINVAL;
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 	struct vlan_mc_entry *mc;
584 	u_int8_t addrlo[ETHER_ADDR_LEN], addrhi[ETHER_ADDR_LEN];
585 	int error;
586 
587 	if (ifr->ifr_addr.sa_len > sizeof(struct sockaddr_storage))
588 		return (EINVAL);
589 
590 	error = ether_addmulti(ifr, &ifv->ifv_ec);
591 	if (error != ENETRESET)
592 		return (error);
593 
594 	/*
595 	 * This is new multicast address.  We have to tell parent
596 	 * about it.  Also, remember this multicast address so that
597 	 * we can delete them on unconfigure.
598 	 */
599 	MALLOC(mc, struct vlan_mc_entry *, sizeof(struct vlan_mc_entry),
600 	    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(&ifr->ifr_addr, addrlo, addrhi);
611 	ETHER_LOOKUP_MULTI(addrlo, addrhi, &ifv->ifv_ec, mc->mc_enm);
612 	memcpy(&mc->mc_addr, &ifr->ifr_addr, ifr->ifr_addr.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 	    (caddr_t)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(ifr, &ifv->ifv_ec);
626 	return (error);
627 }
628 
629 static int
630 vlan_ether_delmulti(struct ifvlan *ifv, struct ifreq *ifr)
631 {
632 	struct ether_multi *enm;
633 	struct vlan_mc_entry *mc;
634 	u_int8_t addrlo[ETHER_ADDR_LEN], addrhi[ETHER_ADDR_LEN];
635 	int error;
636 
637 	/*
638 	 * Find a key to lookup vlan_mc_entry.  We have to do this
639 	 * before calling ether_delmulti for obvious reason.
640 	 */
641 	if ((error = ether_multiaddr(&ifr->ifr_addr, addrlo, addrhi)) != 0)
642 		return (error);
643 	ETHER_LOOKUP_MULTI(addrlo, addrhi, &ifv->ifv_ec, enm);
644 
645 	error = ether_delmulti(ifr, &ifv->ifv_ec);
646 	if (error != ENETRESET)
647 		return (error);
648 
649 	/* We no longer use this multicast address.  Tell parent so. */
650 	error = (*ifv->ifv_p->if_ioctl)(ifv->ifv_p, SIOCDELMULTI,
651 	    (caddr_t)ifr);
652 	if (error == 0) {
653 		/* And forget about this address. */
654 		for (mc = LIST_FIRST(&ifv->ifv_mc_listhead); mc != NULL;
655 		    mc = LIST_NEXT(mc, mc_entries)) {
656 			if (mc->mc_enm == enm) {
657 				LIST_REMOVE(mc, mc_entries);
658 				FREE(mc, M_DEVBUF);
659 				break;
660 			}
661 		}
662 		KASSERT(mc != NULL);
663 	} else
664 		(void)ether_addmulti(ifr, &ifv->ifv_ec);
665 	return (error);
666 }
667 
668 /*
669  * Delete any multicast address we have asked to add from parent
670  * interface.  Called when the vlan is being unconfigured.
671  */
672 static void
673 vlan_ether_purgemulti(struct ifvlan *ifv)
674 {
675 	struct ifnet *ifp = ifv->ifv_p;		/* Parent. */
676 	struct vlan_mc_entry *mc;
677 	union {
678 		struct ifreq ifreq;
679 		struct {
680 			char ifr_name[IFNAMSIZ];
681 			struct sockaddr_storage ifr_ss;
682 		} ifreq_storage;
683 	} ifreq;
684 	struct ifreq *ifr = &ifreq.ifreq;
685 
686 	memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ);
687 	while ((mc = LIST_FIRST(&ifv->ifv_mc_listhead)) != NULL) {
688 		memcpy(&ifr->ifr_addr, &mc->mc_addr, mc->mc_addr.ss_len);
689 		(void)(*ifp->if_ioctl)(ifp, SIOCDELMULTI, (caddr_t)ifr);
690 		LIST_REMOVE(mc, mc_entries);
691 		FREE(mc, M_DEVBUF);
692 	}
693 }
694 
695 static void
696 vlan_start(struct ifnet *ifp)
697 {
698 	struct ifvlan *ifv = ifp->if_softc;
699 	struct ifnet *p = ifv->ifv_p;
700 	struct ethercom *ec = (void *) ifv->ifv_p;
701 	struct mbuf *m;
702 	int error;
703 	ALTQ_DECL(struct altq_pktattr pktattr;)
704 
705 	ifp->if_flags |= IFF_OACTIVE;
706 
707 	for (;;) {
708 		IFQ_DEQUEUE(&ifp->if_snd, m);
709 		if (m == NULL)
710 			break;
711 
712 #ifdef ALTQ
713 		/*
714 		 * If ALTQ is enabled on the parent interface, do
715 		 * classification; the queueing discipline might
716 		 * not require classification, but might require
717 		 * the address family/header pointer in the pktattr.
718 		 */
719 		if (ALTQ_IS_ENABLED(&p->if_snd)) {
720 			switch (p->if_type) {
721 			case IFT_ETHER:
722 				altq_etherclassify(&p->if_snd, m, &pktattr);
723 				break;
724 #ifdef DIAGNOSTIC
725 			default:
726 				panic("vlan_start: impossible (altq)");
727 #endif
728 			}
729 		}
730 #endif /* ALTQ */
731 
732 #if NBPFILTER > 0
733 		if (ifp->if_bpf)
734 			bpf_mtap(ifp->if_bpf, m);
735 #endif
736 		/*
737 		 * If the parent can insert the tag itself, just mark
738 		 * the tag in the mbuf header.
739 		 */
740 		if (ec->ec_capabilities & ETHERCAP_VLAN_HWTAGGING) {
741 			struct m_tag *mtag;
742 
743 			mtag = m_tag_get(PACKET_TAG_VLAN, sizeof(u_int),
744 			    M_NOWAIT);
745 			if (mtag == NULL) {
746 				ifp->if_oerrors++;
747 				m_freem(m);
748 				continue;
749 			}
750 			*(u_int *)(mtag + 1) = ifv->ifv_tag;
751 			m_tag_prepend(m, mtag);
752 		} else {
753 			/*
754 			 * insert the tag ourselves
755 			 */
756 			M_PREPEND(m, ifv->ifv_encaplen, M_DONTWAIT);
757 			if (m == NULL) {
758 				printf("%s: unable to prepend encap header",
759 				    ifv->ifv_p->if_xname);
760 				ifp->if_oerrors++;
761 				continue;
762 			}
763 
764 			switch (p->if_type) {
765 			case IFT_ETHER:
766 			    {
767 				struct ether_vlan_header *evl;
768 
769 				if (m->m_len < sizeof(struct ether_vlan_header))
770 					m = m_pullup(m,
771 					    sizeof(struct ether_vlan_header));
772 				if (m == NULL) {
773 					printf("%s: unable to pullup encap "
774 					    "header", ifv->ifv_p->if_xname);
775 					ifp->if_oerrors++;
776 					continue;
777 				}
778 
779 				/*
780 				 * Transform the Ethernet header into an
781 				 * Ethernet header with 802.1Q encapsulation.
782 				 */
783 				memmove(mtod(m, caddr_t),
784 				    mtod(m, caddr_t) + ifv->ifv_encaplen,
785 				    sizeof(struct ether_header));
786 				evl = mtod(m, struct ether_vlan_header *);
787 				evl->evl_proto = evl->evl_encap_proto;
788 				evl->evl_encap_proto = htons(ETHERTYPE_VLAN);
789 				evl->evl_tag = htons(ifv->ifv_tag);
790 
791 				/*
792 				 * To cater for VLAN-aware layer 2 ethernet
793 				 * switches which may need to strip the tag
794 				 * before forwarding the packet, make sure
795 				 * the packet+tag is at least 68 bytes long.
796 				 * This is necessary because our parent will
797 				 * only pad to 64 bytes (ETHER_MIN_LEN) and
798 				 * some switches will not pad by themselves
799 				 * after deleting a tag.
800 				 */
801 				if (m->m_pkthdr.len <
802 				    (ETHER_MIN_LEN + ETHER_VLAN_ENCAP_LEN)) {
803 					m_copyback(m, m->m_pkthdr.len,
804 					    (ETHER_MIN_LEN +
805 					     ETHER_VLAN_ENCAP_LEN) -
806 					     m->m_pkthdr.len,
807 					    vlan_zero_pad_buff);
808 				}
809 				break;
810 			    }
811 
812 #ifdef DIAGNOSTIC
813 			default:
814 				panic("vlan_start: impossible");
815 #endif
816 			}
817 		}
818 
819 		/*
820 		 * Send it, precisely as the parent's output routine
821 		 * would have.  We are already running at splnet.
822 		 */
823 		IFQ_ENQUEUE(&p->if_snd, m, &pktattr, error);
824 		if (error) {
825 			/* mbuf is already freed */
826 			ifp->if_oerrors++;
827 			continue;
828 		}
829 
830 		ifp->if_opackets++;
831 		if ((p->if_flags & (IFF_RUNNING|IFF_OACTIVE)) == IFF_RUNNING)
832 			(*p->if_start)(p);
833 	}
834 
835 	ifp->if_flags &= ~IFF_OACTIVE;
836 }
837 
838 /*
839  * Given an Ethernet frame, find a valid vlan interface corresponding to the
840  * given source interface and tag, then run the real packet through the
841  * parent's input routine.
842  */
843 void
844 vlan_input(struct ifnet *ifp, struct mbuf *m)
845 {
846 	struct ifvlan *ifv;
847 	u_int tag;
848 	struct m_tag *mtag;
849 
850 	mtag = m_tag_find(m, PACKET_TAG_VLAN, NULL);
851 	if (mtag != NULL) {
852 		/* m contains a normal ethernet frame, the tag is in mtag */
853 		tag = EVL_VLANOFTAG(*(u_int *)(mtag + 1));
854 		m_tag_delete(m, mtag);
855 	} else {
856 		switch (ifp->if_type) {
857 		case IFT_ETHER:
858 		    {
859 			struct ether_vlan_header *evl;
860 
861 			if (m->m_len < sizeof(struct ether_vlan_header) &&
862 			    (m = m_pullup(m,
863 			     sizeof(struct ether_vlan_header))) == NULL) {
864 				printf("%s: no memory for VLAN header, "
865 				    "dropping packet.\n", ifp->if_xname);
866 				return;
867 			}
868 			evl = mtod(m, struct ether_vlan_header *);
869 			KASSERT(ntohs(evl->evl_encap_proto) == ETHERTYPE_VLAN);
870 
871 			tag = EVL_VLANOFTAG(ntohs(evl->evl_tag));
872 
873 			/*
874 			 * Restore the original ethertype.  We'll remove
875 			 * the encapsulation after we've found the vlan
876 			 * interface corresponding to the tag.
877 			 */
878 			evl->evl_encap_proto = evl->evl_proto;
879 			break;
880 		    }
881 
882 		default:
883 			tag = (u_int) -1;	/* XXX GCC */
884 #ifdef DIAGNOSTIC
885 			panic("vlan_input: impossible");
886 #endif
887 		}
888 	}
889 
890 	for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
891 	    ifv = LIST_NEXT(ifv, ifv_list))
892 		if (ifp == ifv->ifv_p && tag == ifv->ifv_tag)
893 			break;
894 
895 	if (ifv == NULL ||
896 	    (ifv->ifv_if.if_flags & (IFF_UP|IFF_RUNNING)) !=
897 	     (IFF_UP|IFF_RUNNING)) {
898 		m_freem(m);
899 		ifp->if_noproto++;
900 		return;
901 	}
902 
903 	/*
904 	 * Now, remove the encapsulation header.  The original
905 	 * header has already been fixed up above.
906 	 */
907 	if (mtag == NULL) {
908 		memmove(mtod(m, caddr_t) + ifv->ifv_encaplen,
909 		    mtod(m, caddr_t), sizeof(struct ether_header));
910 		m_adj(m, ifv->ifv_encaplen);
911 	}
912 
913 	m->m_pkthdr.rcvif = &ifv->ifv_if;
914 	ifv->ifv_if.if_ipackets++;
915 
916 #if NBPFILTER > 0
917 	if (ifv->ifv_if.if_bpf)
918 		bpf_mtap(ifv->ifv_if.if_bpf, m);
919 #endif
920 
921 	/* Pass it back through the parent's input routine. */
922 	(*ifp->if_input)(&ifv->ifv_if, m);
923 }
924