xref: /freebsd/sys/net/if_vlan.c (revision 6780ab54325a71e7e70112b11657973edde8655e)
1 /*
2  * Copyright 1998 Massachusetts Institute of Technology
3  *
4  * Permission to use, copy, modify, and distribute this software and
5  * its documentation for any purpose and without fee is hereby
6  * granted, provided that both the above copyright notice and this
7  * permission notice appear in all copies, that both the above
8  * copyright notice and this permission notice appear in all
9  * supporting documentation, and that the name of M.I.T. not be used
10  * in advertising or publicity pertaining to distribution of the
11  * software without specific, written prior permission.  M.I.T. makes
12  * no representations about the suitability of this software for any
13  * purpose.  It is provided "as is" without express or implied
14  * warranty.
15  *
16  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
17  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
18  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
20  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
23  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
26  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 
32 /*
33  * if_vlan.c - pseudo-device driver for IEEE 802.1Q virtual LANs.
34  * Might be extended some day to also handle IEEE 802.1p priority
35  * tagging.  This is sort of sneaky in the implementation, since
36  * we need to pretend to be enough of an Ethernet implementation
37  * to make arp work.  The way we do this is by telling everyone
38  * that we are an Ethernet, and then catch the packets that
39  * ether_output() left on our output queue when it calls
40  * if_start(), rewrite them for use by the real outgoing interface,
41  * and ask it to send them.
42  */
43 
44 #include "opt_inet.h"
45 
46 #include <sys/param.h>
47 #include <sys/kernel.h>
48 #include <sys/malloc.h>
49 #include <sys/mbuf.h>
50 #include <sys/module.h>
51 #include <sys/queue.h>
52 #include <sys/socket.h>
53 #include <sys/sockio.h>
54 #include <sys/sysctl.h>
55 #include <sys/systm.h>
56 
57 #include <net/bpf.h>
58 #include <net/ethernet.h>
59 #include <net/if.h>
60 #include <net/if_arp.h>
61 #include <net/if_dl.h>
62 #include <net/if_types.h>
63 #include <net/if_vlan_var.h>
64 
65 #ifdef INET
66 #include <netinet/in.h>
67 #include <netinet/if_ether.h>
68 #endif
69 
70 #define VLANNAME	"vlan"
71 
72 struct vlan_mc_entry {
73 	struct ether_addr		mc_addr;
74 	SLIST_ENTRY(vlan_mc_entry)	mc_entries;
75 };
76 
77 struct	ifvlan {
78 	struct	arpcom ifv_ac;	/* make this an interface */
79 	struct	ifnet *ifv_p;	/* parent inteface of this vlan */
80 	struct	ifv_linkmib {
81 		int	ifvm_parent;
82 		int	ifvm_encaplen;	/* encapsulation length */
83 		int	ifvm_mtufudge;	/* MTU fudged by this much */
84 		int	ifvm_mintu;	/* min transmission unit */
85 		u_int16_t ifvm_proto; /* encapsulation ethertype */
86 		u_int16_t ifvm_tag; /* tag to apply on packets leaving if */
87 	}	ifv_mib;
88 	SLIST_HEAD(__vlan_mchead, vlan_mc_entry)	vlan_mc_listhead;
89 	LIST_ENTRY(ifvlan) ifv_list;
90 	int	ifv_flags;
91 };
92 #define	ifv_if	ifv_ac.ac_if
93 #define	ifv_tag	ifv_mib.ifvm_tag
94 #define	ifv_encaplen	ifv_mib.ifvm_encaplen
95 #define	ifv_mtufudge	ifv_mib.ifvm_mtufudge
96 #define	ifv_mintu	ifv_mib.ifvm_mintu
97 
98 #define	IFVF_PROMISC	0x01		/* promiscuous mode enabled */
99 
100 SYSCTL_DECL(_net_link);
101 SYSCTL_NODE(_net_link, IFT_L2VLAN, vlan, CTLFLAG_RW, 0, "IEEE 802.1Q VLAN");
102 SYSCTL_NODE(_net_link_vlan, PF_LINK, link, CTLFLAG_RW, 0, "for consistency");
103 
104 static MALLOC_DEFINE(M_VLAN, "vlan", "802.1Q Virtual LAN Interface");
105 static LIST_HEAD(, ifvlan) ifv_list;
106 
107 static	int vlan_clone_create(struct if_clone *, int);
108 static	void vlan_clone_destroy(struct ifnet *);
109 static	void vlan_start(struct ifnet *ifp);
110 static	void vlan_ifinit(void *foo);
111 static	void vlan_input(struct ifnet *ifp, struct mbuf *m);
112 static	int vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr);
113 static	int vlan_setmulti(struct ifnet *ifp);
114 static	int vlan_unconfig(struct ifnet *ifp);
115 static	int vlan_config(struct ifvlan *ifv, struct ifnet *p);
116 
117 struct if_clone vlan_cloner = IF_CLONE_INITIALIZER("vlan",
118     vlan_clone_create, vlan_clone_destroy, 0, IF_MAXUNIT);
119 
120 /*
121  * Program our multicast filter. What we're actually doing is
122  * programming the multicast filter of the parent. This has the
123  * side effect of causing the parent interface to receive multicast
124  * traffic that it doesn't really want, which ends up being discarded
125  * later by the upper protocol layers. Unfortunately, there's no way
126  * to avoid this: there really is only one physical interface.
127  */
128 static int
129 vlan_setmulti(struct ifnet *ifp)
130 {
131 	struct ifnet		*ifp_p;
132 	struct ifmultiaddr	*ifma, *rifma = NULL;
133 	struct ifvlan		*sc;
134 	struct vlan_mc_entry	*mc = NULL;
135 	struct sockaddr_dl	sdl;
136 	int			error;
137 
138 	/* Find the parent. */
139 	sc = ifp->if_softc;
140 	ifp_p = sc->ifv_p;
141 
142 	/*
143 	 * If we don't have a parent, just remember the membership for
144 	 * when we do.
145 	 */
146 	if (ifp_p == NULL)
147 		return(0);
148 
149 	bzero((char *)&sdl, sizeof sdl);
150 	sdl.sdl_len = sizeof sdl;
151 	sdl.sdl_family = AF_LINK;
152 	sdl.sdl_index = ifp_p->if_index;
153 	sdl.sdl_type = IFT_ETHER;
154 	sdl.sdl_alen = ETHER_ADDR_LEN;
155 
156 	/* First, remove any existing filter entries. */
157 	while(SLIST_FIRST(&sc->vlan_mc_listhead) != NULL) {
158 		mc = SLIST_FIRST(&sc->vlan_mc_listhead);
159 		bcopy((char *)&mc->mc_addr, LLADDR(&sdl), ETHER_ADDR_LEN);
160 		error = if_delmulti(ifp_p, (struct sockaddr *)&sdl);
161 		if (error)
162 			return(error);
163 		SLIST_REMOVE_HEAD(&sc->vlan_mc_listhead, mc_entries);
164 		free(mc, M_VLAN);
165 	}
166 
167 	/* Now program new ones. */
168 	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
169 		if (ifma->ifma_addr->sa_family != AF_LINK)
170 			continue;
171 		mc = malloc(sizeof(struct vlan_mc_entry), M_VLAN, 0);
172 		bcopy(LLADDR((struct sockaddr_dl *)ifma->ifma_addr),
173 		    (char *)&mc->mc_addr, ETHER_ADDR_LEN);
174 		SLIST_INSERT_HEAD(&sc->vlan_mc_listhead, mc, mc_entries);
175 		bcopy(LLADDR((struct sockaddr_dl *)ifma->ifma_addr),
176 		    LLADDR(&sdl), ETHER_ADDR_LEN);
177 		error = if_addmulti(ifp_p, (struct sockaddr *)&sdl, &rifma);
178 		if (error)
179 			return(error);
180 	}
181 
182 	return(0);
183 }
184 
185 /*
186  * VLAN support can be loaded as a module.  The only place in the
187  * system that's intimately aware of this is ether_input.  We hook
188  * into this code through vlan_input_p which is defined there and
189  * set here.  Noone else in the system should be aware of this so
190  * we use an explicit reference here.
191  *
192  * NB: Noone should ever need to check if vlan_input_p is null or
193  *     not.  This is because interfaces have a count of the number
194  *     of active vlans (if_nvlans) and this should never be bumped
195  *     except by vlan_config--which is in this module so therefore
196  *     the module must be loaded and vlan_input_p must be non-NULL.
197  */
198 extern	void (*vlan_input_p)(struct ifnet *, struct mbuf *);
199 
200 static int
201 vlan_modevent(module_t mod, int type, void *data)
202 {
203 
204 	switch (type) {
205 	case MOD_LOAD:
206 		LIST_INIT(&ifv_list);
207 		vlan_input_p = vlan_input;
208 		if_clone_attach(&vlan_cloner);
209 		break;
210 	case MOD_UNLOAD:
211 		if_clone_detach(&vlan_cloner);
212 		vlan_input_p = NULL;
213 		while (!LIST_EMPTY(&ifv_list))
214 			vlan_clone_destroy(&LIST_FIRST(&ifv_list)->ifv_if);
215 		break;
216 	}
217 	return 0;
218 }
219 
220 static moduledata_t vlan_mod = {
221 	"if_vlan",
222 	vlan_modevent,
223 	0
224 };
225 
226 DECLARE_MODULE(if_vlan, vlan_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
227 
228 static int
229 vlan_clone_create(struct if_clone *ifc, int unit)
230 {
231 	struct ifvlan *ifv;
232 	struct ifnet *ifp;
233 	int s;
234 
235 	ifv = malloc(sizeof(struct ifvlan), M_VLAN, M_ZERO);
236 	ifp = &ifv->ifv_if;
237 	SLIST_INIT(&ifv->vlan_mc_listhead);
238 
239 	s = splnet();
240 	LIST_INSERT_HEAD(&ifv_list, ifv, ifv_list);
241 	splx(s);
242 
243 	ifp->if_softc = ifv;
244 	ifp->if_name = "vlan";
245 	ifp->if_unit = unit;
246 	/* NB: flags are not set here */
247 	ifp->if_linkmib = &ifv->ifv_mib;
248 	ifp->if_linkmiblen = sizeof ifv->ifv_mib;
249 	/* NB: mtu is not set here */
250 
251 	ifp->if_init = vlan_ifinit;
252 	ifp->if_start = vlan_start;
253 	ifp->if_ioctl = vlan_ioctl;
254 	ifp->if_snd.ifq_maxlen = ifqmaxlen;
255 	ether_ifattach(ifp, ifv->ifv_ac.ac_enaddr);
256 	/* Now undo some of the damage... */
257 	ifp->if_baudrate = 0;
258 	ifp->if_type = IFT_L2VLAN;
259 	ifp->if_hdrlen = ETHER_VLAN_ENCAP_LEN;
260 
261 	return (0);
262 }
263 
264 static void
265 vlan_clone_destroy(struct ifnet *ifp)
266 {
267 	struct ifvlan *ifv = ifp->if_softc;
268 	int s;
269 
270 	s = splnet();
271 	LIST_REMOVE(ifv, ifv_list);
272 	vlan_unconfig(ifp);
273 	splx(s);
274 
275 	ether_ifdetach(ifp);
276 
277 	free(ifv, M_VLAN);
278 }
279 
280 static void
281 vlan_ifinit(void *foo)
282 {
283 	return;
284 }
285 
286 static void
287 vlan_start(struct ifnet *ifp)
288 {
289 	struct ifvlan *ifv;
290 	struct ifnet *p;
291 	struct ether_vlan_header *evl;
292 	struct mbuf *m;
293 
294 	ifv = ifp->if_softc;
295 	p = ifv->ifv_p;
296 
297 	ifp->if_flags |= IFF_OACTIVE;
298 	for (;;) {
299 		IF_DEQUEUE(&ifp->if_snd, m);
300 		if (m == 0)
301 			break;
302 		BPF_MTAP(ifp, m);
303 
304 		/*
305 		 * Do not run parent's if_start() if the parent is not up,
306 		 * or parent's driver will cause a system crash.
307 		 */
308 		if ((p->if_flags & (IFF_UP | IFF_RUNNING)) !=
309 					(IFF_UP | IFF_RUNNING)) {
310 			m_freem(m);
311 			ifp->if_collisions++;
312 			continue;
313 		}
314 
315 		/*
316 		 * If underlying interface can do VLAN tag insertion itself,
317 		 * just pass the packet along. However, we need some way to
318 		 * tell the interface where the packet came from so that it
319 		 * knows how to find the VLAN tag to use, so we attach a
320 		 * packet tag that holds it.
321 		 */
322 		if (ifp->if_capabilities & IFCAP_VLAN_HWTAGGING) {
323 			struct m_tag *mtag = m_tag_alloc(MTAG_VLAN,
324 							 MTAG_VLAN_TAG,
325 							 sizeof (u_int),
326 							 M_NOWAIT);
327 			if (mtag == NULL) {
328 				ifp->if_oerrors++;
329 				m_freem(m);
330 				continue;
331 			}
332 			*(u_int*)(mtag+1) = ifv->ifv_tag;
333 			m_tag_prepend(m, mtag);
334 		} else {
335 			M_PREPEND(m, ifv->ifv_encaplen, M_NOWAIT);
336 			if (m == NULL) {
337 				if_printf(ifp, "unable to prepend VLAN header");
338 				ifp->if_ierrors++;
339 				continue;
340 			}
341 			/* M_PREPEND takes care of m_len, m_pkthdr.len for us */
342 
343 			if (m->m_len < sizeof(*evl)) {
344 				m = m_pullup(m, sizeof(*evl));
345 				if (m == NULL) {
346 					if_printf(ifp,
347 					    "cannot pullup VLAN header");
348 					ifp->if_ierrors++;
349 					continue;
350 				}
351 			}
352 
353 			/*
354 			 * Transform the Ethernet header into an Ethernet header
355 			 * with 802.1Q encapsulation.
356 			 */
357 			bcopy(mtod(m, char *) + ifv->ifv_encaplen,
358 			      mtod(m, char *), sizeof(struct ether_header));
359 			evl = mtod(m, struct ether_vlan_header *);
360 			evl->evl_proto = evl->evl_encap_proto;
361 			evl->evl_encap_proto = htons(ETHERTYPE_VLAN);
362 			evl->evl_tag = htons(ifv->ifv_tag);
363 #ifdef DEBUG
364 			printf("vlan_start: %*D\n", (int)sizeof *evl,
365 			    (unsigned char *)evl, ":");
366 #endif
367 		}
368 
369 		/*
370 		 * Send it, precisely as ether_output() would have.
371 		 * We are already running at splimp.
372 		 */
373 		if (IF_HANDOFF(&p->if_snd, m, p))
374 			ifp->if_opackets++;
375 		else
376 			ifp->if_oerrors++;
377 	}
378 	ifp->if_flags &= ~IFF_OACTIVE;
379 
380 	return;
381 }
382 
383 static void
384 vlan_input(struct ifnet *ifp, struct mbuf *m)
385 {
386 	struct ether_vlan_header *evl;
387 	struct ifvlan *ifv;
388 	struct m_tag *mtag;
389 	u_int tag;
390 
391 	mtag = m_tag_locate(m, MTAG_VLAN, MTAG_VLAN_TAG, NULL);
392 	if (mtag != NULL) {
393 		/*
394 		 * Packet is tagged, m contains a normal
395 		 * Ethernet frame; the tag is stored out-of-band.
396 		 */
397 		tag = *(u_int*)(mtag+1);
398 		m_tag_delete(m, mtag);
399 	} else {
400 		switch (ifp->if_type) {
401 		case IFT_ETHER:
402 			if (m->m_len < sizeof (*evl) &&
403 			    (m = m_pullup(m, sizeof (*evl))) == NULL) {
404 				if_printf(ifp, "cannot pullup VLAN header\n");
405 				return;
406 			}
407 			evl = mtod(m, struct ether_vlan_header *);
408 			KASSERT(ntohs(evl->evl_encap_proto) == ETHERTYPE_VLAN,
409 				("vlan_input: bad encapsulated protocols (%u)",
410 				 ntohs(evl->evl_encap_proto)));
411 
412 			tag = EVL_VLANOFTAG(ntohs(evl->evl_tag));
413 
414 			/*
415 			 * Restore the original ethertype.  We'll remove
416 			 * the encapsulation after we've found the vlan
417 			 * interface corresponding to the tag.
418 			 */
419 			evl->evl_encap_proto = evl->evl_proto;
420 			break;
421 		default:
422 			tag = (u_int) -1;
423 #ifdef DIAGNOSTIC
424 			panic("vlan_input: unsupported if type %u", ifp->if_type);
425 #endif
426 			break;
427 		}
428 	}
429 
430 	for (ifv = LIST_FIRST(&ifv_list); ifv != NULL;
431 	    ifv = LIST_NEXT(ifv, ifv_list))
432 		if (ifp == ifv->ifv_p && tag == ifv->ifv_tag)
433 			break;
434 
435 	if (ifv == NULL || (ifv->ifv_if.if_flags & IFF_UP) == 0) {
436 		m_freem(m);
437 		ifp->if_noproto++;
438 		return;
439 	}
440 
441 	if (mtag == NULL) {
442 		/*
443 		 * Packet had an in-line encapsulation header;
444 		 * remove it.  The original header has already
445 		 * been fixed up above.
446 		 */
447 		bcopy(mtod(m, caddr_t),
448 		      mtod(m, caddr_t) + ETHER_VLAN_ENCAP_LEN,
449 		      sizeof (struct ether_header));
450 		m_adj(m, ETHER_VLAN_ENCAP_LEN);
451 	}
452 
453 	m->m_pkthdr.rcvif = &ifv->ifv_if;
454 	ifv->ifv_if.if_ipackets++;
455 
456 	/* Pass it back through the parent's input routine. */
457 	(*ifp->if_input)(&ifv->ifv_if, m);
458 }
459 
460 static int
461 vlan_config(struct ifvlan *ifv, struct ifnet *p)
462 {
463 	struct ifaddr *ifa1, *ifa2;
464 	struct sockaddr_dl *sdl1, *sdl2;
465 
466 	if (p->if_data.ifi_type != IFT_ETHER)
467 		return EPROTONOSUPPORT;
468 	if (ifv->ifv_p)
469 		return EBUSY;
470 
471 	ifv->ifv_encaplen = ETHER_VLAN_ENCAP_LEN;
472 	ifv->ifv_mintu = ETHERMIN;
473 	ifv->ifv_flags = 0;
474 
475 	/*
476 	 * If the parent supports the VLAN_MTU capability,
477 	 * i.e. can Tx/Rx larger than ETHER_MAX_LEN frames,
478 	 * enable it.
479 	 */
480 	p->if_nvlans++;
481 	if (p->if_nvlans == 1 && (p->if_capabilities & IFCAP_VLAN_MTU) != 0) {
482 		/*
483 		 * Enable Tx/Rx of VLAN-sized frames.
484 		 */
485 		p->if_capenable |= IFCAP_VLAN_MTU;
486 		if (p->if_flags & IFF_UP) {
487 			struct ifreq ifr;
488 			int error;
489 
490 			ifr.ifr_flags = p->if_flags;
491 			error = (*p->if_ioctl)(p, SIOCSIFFLAGS,
492 			    (caddr_t) &ifr);
493 			if (error) {
494 				p->if_nvlans--;
495 				if (p->if_nvlans == 0)
496 					p->if_capenable &= ~IFCAP_VLAN_MTU;
497 				return (error);
498 			}
499 		}
500 		ifv->ifv_mtufudge = 0;
501 	} else if ((p->if_capabilities & IFCAP_VLAN_MTU) == 0) {
502 		/*
503 		 * Fudge the MTU by the encapsulation size.  This
504 		 * makes us incompatible with strictly compliant
505 		 * 802.1Q implementations, but allows us to use
506 		 * the feature with other NetBSD implementations,
507 		 * which might still be useful.
508 		 */
509 		ifv->ifv_mtufudge = ifv->ifv_encaplen;
510 	}
511 
512 	ifv->ifv_p = p;
513 	ifv->ifv_if.if_mtu = p->if_mtu - ifv->ifv_mtufudge;
514 	/*
515 	 * Copy only a selected subset of flags from the parent.
516 	 * Other flags are none of our business.
517 	 */
518 	ifv->ifv_if.if_flags = (p->if_flags &
519 	    (IFF_BROADCAST | IFF_MULTICAST | IFF_SIMPLEX | IFF_POINTOPOINT));
520 
521 	/*
522 	 * If the parent interface can do hardware-assisted
523 	 * VLAN encapsulation, then propagate its hardware-
524 	 * assisted checksumming flags.
525 	 */
526 	if (p->if_capabilities & IFCAP_VLAN_HWTAGGING)
527 		ifv->ifv_if.if_capabilities |= p->if_capabilities & IFCAP_HWCSUM;
528 
529 	/*
530 	 * Set up our ``Ethernet address'' to reflect the underlying
531 	 * physical interface's.
532 	 */
533 	ifa1 = ifaddr_byindex(ifv->ifv_if.if_index);
534 	ifa2 = ifaddr_byindex(p->if_index);
535 	sdl1 = (struct sockaddr_dl *)ifa1->ifa_addr;
536 	sdl2 = (struct sockaddr_dl *)ifa2->ifa_addr;
537 	sdl1->sdl_type = IFT_ETHER;
538 	sdl1->sdl_alen = ETHER_ADDR_LEN;
539 	bcopy(LLADDR(sdl2), LLADDR(sdl1), ETHER_ADDR_LEN);
540 	bcopy(LLADDR(sdl2), ifv->ifv_ac.ac_enaddr, ETHER_ADDR_LEN);
541 
542 	/*
543 	 * Configure multicast addresses that may already be
544 	 * joined on the vlan device.
545 	 */
546 	(void)vlan_setmulti(&ifv->ifv_if);
547 
548 	return 0;
549 }
550 
551 static int
552 vlan_unconfig(struct ifnet *ifp)
553 {
554 	struct ifaddr *ifa;
555 	struct sockaddr_dl *sdl;
556 	struct vlan_mc_entry *mc;
557 	struct ifvlan *ifv;
558 	struct ifnet *p;
559 	int error;
560 
561 	ifv = ifp->if_softc;
562 	p = ifv->ifv_p;
563 
564 	if (p) {
565 		struct sockaddr_dl sdl;
566 
567 		/*
568 		 * Since the interface is being unconfigured, we need to
569 		 * empty the list of multicast groups that we may have joined
570 		 * while we were alive from the parent's list.
571 		 */
572 		bzero((char *)&sdl, sizeof sdl);
573 		sdl.sdl_len = sizeof sdl;
574 		sdl.sdl_family = AF_LINK;
575 		sdl.sdl_index = p->if_index;
576 		sdl.sdl_type = IFT_ETHER;
577 		sdl.sdl_alen = ETHER_ADDR_LEN;
578 
579 		while(SLIST_FIRST(&ifv->vlan_mc_listhead) != NULL) {
580 			mc = SLIST_FIRST(&ifv->vlan_mc_listhead);
581 			bcopy((char *)&mc->mc_addr, LLADDR(&sdl), ETHER_ADDR_LEN);
582 			error = if_delmulti(p, (struct sockaddr *)&sdl);
583 			if (error)
584 				return(error);
585 			SLIST_REMOVE_HEAD(&ifv->vlan_mc_listhead, mc_entries);
586 			free(mc, M_VLAN);
587 		}
588 
589 		p->if_nvlans--;
590 		if (p->if_nvlans == 0) {
591 			/*
592 			 * Disable Tx/Rx of VLAN-sized frames.
593 			 */
594 			p->if_capenable &= ~IFCAP_VLAN_MTU;
595 			if (p->if_flags & IFF_UP) {
596 				struct ifreq ifr;
597 
598 				ifr.ifr_flags = p->if_flags;
599 				(*p->if_ioctl)(p, SIOCSIFFLAGS, (caddr_t) &ifr);
600 			}
601 		}
602 	}
603 
604 	/* Disconnect from parent. */
605 	ifv->ifv_p = NULL;
606 	ifv->ifv_if.if_mtu = ETHERMTU;		/* XXX why not 0? */
607 	ifv->ifv_flags = 0;
608 
609 	/* Clear our MAC address. */
610 	ifa = ifaddr_byindex(ifv->ifv_if.if_index);
611 	sdl = (struct sockaddr_dl *)ifa->ifa_addr;
612 	sdl->sdl_type = IFT_ETHER;
613 	sdl->sdl_alen = ETHER_ADDR_LEN;
614 	bzero(LLADDR(sdl), ETHER_ADDR_LEN);
615 	bzero(ifv->ifv_ac.ac_enaddr, ETHER_ADDR_LEN);
616 
617 	return 0;
618 }
619 
620 static int
621 vlan_set_promisc(struct ifnet *ifp)
622 {
623 	struct ifvlan *ifv = ifp->if_softc;
624 	int error = 0;
625 
626 	if ((ifp->if_flags & IFF_PROMISC) != 0) {
627 		if ((ifv->ifv_flags & IFVF_PROMISC) == 0) {
628 			error = ifpromisc(ifv->ifv_p, 1);
629 			if (error == 0)
630 				ifv->ifv_flags |= IFVF_PROMISC;
631 		}
632 	} else {
633 		if ((ifv->ifv_flags & IFVF_PROMISC) != 0) {
634 			error = ifpromisc(ifv->ifv_p, 0);
635 			if (error == 0)
636 				ifv->ifv_flags &= ~IFVF_PROMISC;
637 		}
638 	}
639 
640 	return (error);
641 }
642 
643 static int
644 vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
645 {
646 	struct ifaddr *ifa;
647 	struct ifnet *p;
648 	struct ifreq *ifr;
649 	struct ifvlan *ifv;
650 	struct vlanreq vlr;
651 	int error = 0;
652 
653 	ifr = (struct ifreq *)data;
654 	ifa = (struct ifaddr *)data;
655 	ifv = ifp->if_softc;
656 
657 	switch (cmd) {
658 	case SIOCSIFADDR:
659 		ifp->if_flags |= IFF_UP;
660 
661 		switch (ifa->ifa_addr->sa_family) {
662 #ifdef INET
663 		case AF_INET:
664 			arp_ifinit(&ifv->ifv_if, ifa);
665 			break;
666 #endif
667 		default:
668 			break;
669 		}
670 		break;
671 
672 	case SIOCGIFADDR:
673 		{
674 			struct sockaddr *sa;
675 
676 			sa = (struct sockaddr *) &ifr->ifr_data;
677 			bcopy(((struct arpcom *)ifp->if_softc)->ac_enaddr,
678 			      (caddr_t) sa->sa_data, ETHER_ADDR_LEN);
679 		}
680 		break;
681 
682 	case SIOCGIFMEDIA:
683 		if (ifv->ifv_p != NULL) {
684 			error = (ifv->ifv_p->if_ioctl)(ifv->ifv_p, SIOCGIFMEDIA, data);
685 			/* Limit the result to the parent's current config. */
686 			if (error == 0) {
687 				struct ifmediareq *ifmr;
688 
689 				ifmr = (struct ifmediareq *) data;
690 				if (ifmr->ifm_count >= 1 && ifmr->ifm_ulist) {
691 					ifmr->ifm_count = 1;
692 					error = copyout(&ifmr->ifm_current,
693 						ifmr->ifm_ulist,
694 						sizeof(int));
695 				}
696 			}
697 		} else
698 			error = EINVAL;
699 		break;
700 
701 	case SIOCSIFMEDIA:
702 		error = EINVAL;
703 		break;
704 
705 	case SIOCSIFMTU:
706 		/*
707 		 * Set the interface MTU.
708 		 */
709 		if (ifv->ifv_p != NULL) {
710 			if (ifr->ifr_mtu >
711 			     (ifv->ifv_p->if_mtu - ifv->ifv_mtufudge) ||
712 			    ifr->ifr_mtu <
713 			     (ifv->ifv_mintu - ifv->ifv_mtufudge))
714 				error = EINVAL;
715 			else
716 				ifp->if_mtu = ifr->ifr_mtu;
717 		} else
718 			error = EINVAL;
719 		break;
720 
721 	case SIOCSETVLAN:
722 		error = copyin(ifr->ifr_data, &vlr, sizeof vlr);
723 		if (error)
724 			break;
725 		if (vlr.vlr_parent[0] == '\0') {
726 			vlan_unconfig(ifp);
727 			if (ifp->if_flags & IFF_UP) {
728 				int s = splimp();
729 				if_down(ifp);
730 				splx(s);
731 			}
732 			ifp->if_flags &= ~IFF_RUNNING;
733 			break;
734 		}
735 		p = ifunit(vlr.vlr_parent);
736 		if (p == 0) {
737 			error = ENOENT;
738 			break;
739 		}
740 		error = vlan_config(ifv, p);
741 		if (error)
742 			break;
743 		ifv->ifv_tag = vlr.vlr_tag;
744 		ifp->if_flags |= IFF_RUNNING;
745 
746 		/* Update promiscuous mode, if necessary. */
747 		vlan_set_promisc(ifp);
748 		break;
749 
750 	case SIOCGETVLAN:
751 		bzero(&vlr, sizeof vlr);
752 		if (ifv->ifv_p) {
753 			snprintf(vlr.vlr_parent, sizeof(vlr.vlr_parent),
754 			    "%s%d", ifv->ifv_p->if_name, ifv->ifv_p->if_unit);
755 			vlr.vlr_tag = ifv->ifv_tag;
756 		}
757 		error = copyout(&vlr, ifr->ifr_data, sizeof vlr);
758 		break;
759 
760 	case SIOCSIFFLAGS:
761 		/*
762 		 * For promiscuous mode, we enable promiscuous mode on
763 		 * the parent if we need promiscuous on the VLAN interface.
764 		 */
765 		if (ifv->ifv_p != NULL)
766 			error = vlan_set_promisc(ifp);
767 		break;
768 
769 	case SIOCADDMULTI:
770 	case SIOCDELMULTI:
771 		error = vlan_setmulti(ifp);
772 		break;
773 	default:
774 		error = EINVAL;
775 	}
776 	return error;
777 }
778