xref: /illumos-gate/usr/src/uts/common/io/dls/dls.c (revision 9e4af98f99ed7cc13379dff1aca68e7a3dfe29bd)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  * Copyright 2012, Nexenta Systems, Inc. All rights reserved.
25  */
26 
27 /*
28  * Copyright 2019 Joyent, Inc.
29  */
30 
31 /*
32  * Data-Link Services Module
33  */
34 
35 #include	<sys/strsun.h>
36 #include	<sys/vlan.h>
37 #include	<sys/dld_impl.h>
38 #include	<sys/mac_client_priv.h>
39 
40 int
41 dls_open(dls_link_t *dlp, dls_dl_handle_t ddh, dld_str_t *dsp)
42 {
43 	zoneid_t	zid = getzoneid();
44 	boolean_t	local;
45 	int		err;
46 
47 	/*
48 	 * Check whether this client belongs to the zone of this dlp. Note that
49 	 * a global zone client is allowed to open a local zone dlp.
50 	 */
51 	if (zid != GLOBAL_ZONEID && dlp->dl_zid != zid)
52 		return (ENOENT);
53 
54 	/*
55 	 * mac_start() is required for non-legacy MACs to show accurate
56 	 * kstats even before the interface is brought up. For legacy
57 	 * drivers, this is not needed. Further, calling mac_start() for
58 	 * legacy drivers would make the shared-lower-stream to stay in
59 	 * the DL_IDLE state, which in turn causes performance regression.
60 	 */
61 	if (!mac_capab_get(dlp->dl_mh, MAC_CAPAB_LEGACY, NULL) &&
62 	    ((err = mac_start(dlp->dl_mh)) != 0)) {
63 		return (err);
64 	}
65 
66 	local = (zid == dlp->dl_zid);
67 	dlp->dl_zone_ref += (local ? 1 : 0);
68 
69 	/*
70 	 * Cache a copy of the MAC interface handle, a pointer to the
71 	 * immutable MAC info.
72 	 */
73 	dsp->ds_dlp = dlp;
74 	dsp->ds_mh = dlp->dl_mh;
75 	dsp->ds_mch = dlp->dl_mch;
76 	dsp->ds_mip = dlp->dl_mip;
77 	dsp->ds_ddh = ddh;
78 	dsp->ds_local = local;
79 
80 	ASSERT(MAC_PERIM_HELD(dsp->ds_mh));
81 	return (0);
82 }
83 
84 void
85 dls_close(dld_str_t *dsp)
86 {
87 	dls_link_t		*dlp = dsp->ds_dlp;
88 	dls_multicst_addr_t	*p;
89 	dls_multicst_addr_t	*nextp;
90 
91 	ASSERT(dsp->ds_datathr_cnt == 0);
92 	ASSERT(MAC_PERIM_HELD(dsp->ds_mh));
93 
94 	if (dsp->ds_local)
95 		dlp->dl_zone_ref--;
96 	dsp->ds_local = B_FALSE;
97 
98 	/*
99 	 * Walk the list of multicast addresses, disabling each at the MAC.
100 	 * Note that we must remove multicast address before
101 	 * mac_unicast_remove() (called by dls_active_clear()) because
102 	 * mac_multicast_remove() relies on the unicast flows on the mac
103 	 * client.
104 	 */
105 	for (p = dsp->ds_dmap; p != NULL; p = nextp) {
106 		(void) mac_multicast_remove(dsp->ds_mch, p->dma_addr);
107 		nextp = p->dma_nextp;
108 		kmem_free(p, sizeof (dls_multicst_addr_t));
109 	}
110 	dsp->ds_dmap = NULL;
111 
112 	dls_active_clear(dsp, B_TRUE);
113 
114 	/*
115 	 * If the dld_str_t is bound then unbind it.
116 	 */
117 	if (dsp->ds_dlstate == DL_IDLE) {
118 		dls_unbind(dsp);
119 		dsp->ds_dlstate = DL_UNBOUND;
120 	}
121 
122 	/*
123 	 * If the MAC has been set in promiscuous mode then disable it.
124 	 * This needs to be done before resetting ds_rx.
125 	 */
126 	(void) dls_promisc(dsp, 0);
127 
128 	/*
129 	 * At this point we have cutoff inbound packet flow from the mac
130 	 * for this 'dsp'. The dls_link_remove above cut off packets meant
131 	 * for us and waited for upcalls to finish. Similarly the dls_promisc
132 	 * reset above waited for promisc callbacks to finish. Now we can
133 	 * safely reset ds_rx to NULL
134 	 */
135 	dsp->ds_rx = NULL;
136 	dsp->ds_rx_arg = NULL;
137 
138 	dsp->ds_dlp = NULL;
139 
140 	if (!mac_capab_get(dsp->ds_mh, MAC_CAPAB_LEGACY, NULL))
141 		mac_stop(dsp->ds_mh);
142 
143 	/*
144 	 * Release our reference to the dls_link_t allowing that to be
145 	 * destroyed if there are no more dls_impl_t.
146 	 */
147 	dls_link_rele(dlp);
148 }
149 
150 int
151 dls_bind(dld_str_t *dsp, uint32_t sap)
152 {
153 	uint32_t	dls_sap;
154 
155 	ASSERT(MAC_PERIM_HELD(dsp->ds_mh));
156 
157 	/*
158 	 * Check to see the value is legal for the media type.
159 	 */
160 	if (!mac_sap_verify(dsp->ds_mh, sap, &dls_sap))
161 		return (EINVAL);
162 
163 	if (dsp->ds_promisc & DLS_PROMISC_SAP)
164 		dls_sap = DLS_SAP_PROMISC;
165 
166 	/*
167 	 * Set up the dld_str_t to mark it as able to receive packets.
168 	 */
169 	dsp->ds_sap = sap;
170 
171 	/*
172 	 * The MAC layer does the VLAN demultiplexing and will only pass up
173 	 * untagged packets to non-promiscuous primary MAC clients. In order to
174 	 * support the binding to the VLAN SAP which is required by DLPI, dls
175 	 * needs to get a copy of all tagged packets when the client binds to
176 	 * the VLAN SAP. We do this by registering a separate promiscuous
177 	 * callback for each dls client binding to that SAP.
178 	 *
179 	 * Note: even though there are two promiscuous handles in dld_str_t,
180 	 * ds_mph is for the regular promiscuous mode, ds_vlan_mph is the handle
181 	 * to receive VLAN pkt when promiscuous mode is not on. Only one of
182 	 * them can be non-NULL at the same time, to avoid receiving dup copies
183 	 * of pkts.
184 	 */
185 	if (sap == ETHERTYPE_VLAN && dsp->ds_promisc == 0) {
186 		int err;
187 
188 		if (dsp->ds_vlan_mph != NULL)
189 			return (EINVAL);
190 		err = mac_promisc_add(dsp->ds_mch,
191 		    MAC_CLIENT_PROMISC_ALL, dls_rx_vlan_promisc, dsp,
192 		    &dsp->ds_vlan_mph, MAC_PROMISC_FLAGS_NO_PHYS);
193 
194 		if (err == 0 && dsp->ds_nonip &&
195 		    dsp->ds_dlp->dl_nonip_cnt++ == 0)
196 			mac_rx_bypass_disable(dsp->ds_mch);
197 
198 		return (err);
199 	}
200 
201 	/*
202 	 * Now bind the dld_str_t by adding it into the hash table in the
203 	 * dls_link_t.
204 	 */
205 	dls_link_add(dsp->ds_dlp, dls_sap, dsp);
206 	if (dsp->ds_nonip && dsp->ds_dlp->dl_nonip_cnt++ == 0)
207 		mac_rx_bypass_disable(dsp->ds_mch);
208 
209 	return (0);
210 }
211 
212 void
213 dls_unbind(dld_str_t *dsp)
214 {
215 	ASSERT(MAC_PERIM_HELD(dsp->ds_mh));
216 
217 	if (dsp->ds_nonip && --dsp->ds_dlp->dl_nonip_cnt == 0)
218 		mac_rx_bypass_enable(dsp->ds_mch);
219 
220 	/*
221 	 * A VLAN SAP does not actually add itself to the STREAM head today.
222 	 * While we initially set up a VLAN handle below, it's possible that
223 	 * something else will have come in and clobbered it.
224 	 */
225 	if (dsp->ds_sap == ETHERTYPE_VLAN) {
226 		if (dsp->ds_vlan_mph != NULL) {
227 			mac_promisc_remove(dsp->ds_vlan_mph);
228 			dsp->ds_vlan_mph = NULL;
229 		}
230 		return;
231 	}
232 
233 	/*
234 	 * Unbind the dld_str_t by removing it from the hash table in the
235 	 * dls_link_t.
236 	 */
237 	dls_link_remove(dsp->ds_dlp, dsp);
238 	dsp->ds_sap = 0;
239 }
240 
241 /*
242  * In order to prevent promiscuous-mode processing with dsp->ds_promisc
243  * set to inaccurate values, this function sets dsp->ds_promisc with new
244  * flags.  For enabling (mac_promisc_add), the flags are set prior to the
245  * actual enabling.  For disabling (mac_promisc_remove), the flags are set
246  * after the actual disabling.
247  */
248 int
249 dls_promisc(dld_str_t *dsp, uint32_t new_flags)
250 {
251 	int err = 0;
252 	uint32_t old_flags = dsp->ds_promisc;
253 	mac_client_promisc_type_t mptype = MAC_CLIENT_PROMISC_ALL;
254 
255 	ASSERT(MAC_PERIM_HELD(dsp->ds_mh));
256 	ASSERT(!(new_flags & ~(DLS_PROMISC_SAP | DLS_PROMISC_MULTI |
257 	    DLS_PROMISC_PHYS)));
258 
259 	/*
260 	 * If the user has only requested DLS_PROMISC_MULTI then we need to make
261 	 * sure that they don't see all packets.
262 	 */
263 	if (new_flags == DLS_PROMISC_MULTI)
264 		mptype = MAC_CLIENT_PROMISC_MULTI;
265 
266 	if (dsp->ds_promisc == 0 && new_flags != 0) {
267 		/*
268 		 * If only DLS_PROMISC_SAP, we don't turn on the
269 		 * physical promisc mode
270 		 */
271 		dsp->ds_promisc = new_flags;
272 		err = mac_promisc_add(dsp->ds_mch, mptype,
273 		    dls_rx_promisc, dsp, &dsp->ds_mph,
274 		    (new_flags != DLS_PROMISC_SAP) ? 0 :
275 		    MAC_PROMISC_FLAGS_NO_PHYS);
276 		if (err != 0) {
277 			dsp->ds_promisc = old_flags;
278 			return (err);
279 		}
280 
281 		/* Remove vlan promisc handle to avoid sending dup copy up */
282 		if (dsp->ds_vlan_mph != NULL) {
283 			mac_promisc_remove(dsp->ds_vlan_mph);
284 			dsp->ds_vlan_mph = NULL;
285 		}
286 	} else if (dsp->ds_promisc != 0 && new_flags == 0) {
287 		ASSERT(dsp->ds_mph != NULL);
288 
289 		mac_promisc_remove(dsp->ds_mph);
290 		dsp->ds_promisc = new_flags;
291 		dsp->ds_mph = NULL;
292 
293 		if (dsp->ds_sap == ETHERTYPE_VLAN &&
294 		    dsp->ds_dlstate != DL_UNBOUND) {
295 			if (dsp->ds_vlan_mph != NULL)
296 				return (EINVAL);
297 			err = mac_promisc_add(dsp->ds_mch,
298 			    MAC_CLIENT_PROMISC_ALL, dls_rx_vlan_promisc, dsp,
299 			    &dsp->ds_vlan_mph, MAC_PROMISC_FLAGS_NO_PHYS);
300 		}
301 	} else if (dsp->ds_promisc == DLS_PROMISC_SAP && new_flags != 0 &&
302 	    new_flags != dsp->ds_promisc) {
303 		/*
304 		 * If the old flag is PROMISC_SAP, but the current flag has
305 		 * changed to some new non-zero value, we need to turn the
306 		 * physical promiscuous mode.
307 		 */
308 		ASSERT(dsp->ds_mph != NULL);
309 		mac_promisc_remove(dsp->ds_mph);
310 		/* Honors both after-remove and before-add semantics! */
311 		dsp->ds_promisc = new_flags;
312 		err = mac_promisc_add(dsp->ds_mch, mptype,
313 		    dls_rx_promisc, dsp, &dsp->ds_mph, 0);
314 		if (err != 0)
315 			dsp->ds_promisc = old_flags;
316 	} else {
317 		/* No adding or removing, but record the new flags anyway. */
318 		dsp->ds_promisc = new_flags;
319 	}
320 
321 	return (err);
322 }
323 
324 int
325 dls_multicst_add(dld_str_t *dsp, const uint8_t *addr)
326 {
327 	int			err;
328 	dls_multicst_addr_t	**pp;
329 	dls_multicst_addr_t	*p;
330 	uint_t			addr_length;
331 
332 	ASSERT(MAC_PERIM_HELD(dsp->ds_mh));
333 
334 	/*
335 	 * Check whether the address is in the list of enabled addresses for
336 	 * this dld_str_t.
337 	 */
338 	addr_length = dsp->ds_mip->mi_addr_length;
339 
340 	/*
341 	 * Protect against concurrent access of ds_dmap by data threads using
342 	 * ds_rw_lock. The mac perimeter serializes the dls_multicst_add and
343 	 * remove operations. Dropping the ds_rw_lock across mac calls is thus
344 	 * ok and is also required by the locking protocol.
345 	 */
346 	rw_enter(&dsp->ds_rw_lock, RW_WRITER);
347 	for (pp = &(dsp->ds_dmap); (p = *pp) != NULL; pp = &(p->dma_nextp)) {
348 		if (bcmp(addr, p->dma_addr, addr_length) == 0) {
349 			/*
350 			 * It is there so there's nothing to do.
351 			 */
352 			err = 0;
353 			goto done;
354 		}
355 	}
356 
357 	/*
358 	 * Allocate a new list item and add it to the list.
359 	 */
360 	p = kmem_zalloc(sizeof (dls_multicst_addr_t), KM_SLEEP);
361 	bcopy(addr, p->dma_addr, addr_length);
362 	*pp = p;
363 	rw_exit(&dsp->ds_rw_lock);
364 
365 	/*
366 	 * Enable the address at the MAC.
367 	 */
368 	err = mac_multicast_add(dsp->ds_mch, addr);
369 	if (err == 0)
370 		return (0);
371 
372 	/* Undo the operation as it has failed */
373 	rw_enter(&dsp->ds_rw_lock, RW_WRITER);
374 	ASSERT(*pp == p && p->dma_nextp == NULL);
375 	*pp = NULL;
376 	kmem_free(p, sizeof (dls_multicst_addr_t));
377 done:
378 	rw_exit(&dsp->ds_rw_lock);
379 	return (err);
380 }
381 
382 int
383 dls_multicst_remove(dld_str_t *dsp, const uint8_t *addr)
384 {
385 	dls_multicst_addr_t	**pp;
386 	dls_multicst_addr_t	*p;
387 	uint_t			addr_length;
388 
389 	ASSERT(MAC_PERIM_HELD(dsp->ds_mh));
390 
391 	/*
392 	 * Find the address in the list of enabled addresses for this
393 	 * dld_str_t.
394 	 */
395 	addr_length = dsp->ds_mip->mi_addr_length;
396 
397 	/*
398 	 * Protect against concurrent access to ds_dmap by data threads using
399 	 * ds_rw_lock. The mac perimeter serializes the dls_multicst_add and
400 	 * remove operations. Dropping the ds_rw_lock across mac calls is thus
401 	 * ok and is also required by the locking protocol.
402 	 */
403 	rw_enter(&dsp->ds_rw_lock, RW_WRITER);
404 	for (pp = &(dsp->ds_dmap); (p = *pp) != NULL; pp = &(p->dma_nextp)) {
405 		if (bcmp(addr, p->dma_addr, addr_length) == 0)
406 			break;
407 	}
408 
409 	/*
410 	 * If we walked to the end of the list then the given address is
411 	 * not currently enabled for this dld_str_t.
412 	 */
413 	if (p == NULL) {
414 		rw_exit(&dsp->ds_rw_lock);
415 		return (ENOENT);
416 	}
417 
418 	/*
419 	 * Remove the address from the list.
420 	 */
421 	*pp = p->dma_nextp;
422 	rw_exit(&dsp->ds_rw_lock);
423 
424 	/*
425 	 * Disable the address at the MAC.
426 	 */
427 	mac_multicast_remove(dsp->ds_mch, addr);
428 	kmem_free(p, sizeof (dls_multicst_addr_t));
429 	return (0);
430 }
431 
432 mblk_t *
433 dls_header(dld_str_t *dsp, const uint8_t *addr, uint16_t sap, uint_t pri,
434     mblk_t **payloadp)
435 {
436 	uint16_t vid;
437 	size_t extra_len;
438 	uint16_t mac_sap;
439 	mblk_t *mp, *payload;
440 	boolean_t is_ethernet = (dsp->ds_mip->mi_media == DL_ETHER);
441 	struct ether_vlan_header *evhp;
442 
443 	vid = mac_client_vid(dsp->ds_mch);
444 	payload = (payloadp == NULL) ? NULL : (*payloadp);
445 
446 	/*
447 	 * In the case of Ethernet, we need to tell mac_header() if we need
448 	 * extra room beyond the Ethernet header for a VLAN header.  We'll
449 	 * need to add a VLAN header if this isn't an ETHERTYPE_VLAN listener
450 	 * (because such streams will be handling VLAN headers on their own)
451 	 * and one of the following conditions is satisfied:
452 	 *
453 	 * - This is a VLAN stream
454 	 * - This is a physical stream, the priority is not 0, and user
455 	 *   priority tagging is allowed.
456 	 */
457 	if (is_ethernet && sap != ETHERTYPE_VLAN &&
458 	    (vid != VLAN_ID_NONE ||
459 	    (pri != 0 && dsp->ds_dlp->dl_tagmode != LINK_TAGMODE_VLANONLY))) {
460 		extra_len = sizeof (struct ether_vlan_header) -
461 		    sizeof (struct ether_header);
462 		mac_sap = ETHERTYPE_VLAN;
463 	} else {
464 		extra_len = 0;
465 		mac_sap = sap;
466 	}
467 
468 	mp = mac_header(dsp->ds_mh, addr, mac_sap, payload, extra_len);
469 	if (mp == NULL)
470 		return (NULL);
471 
472 	if ((vid == VLAN_ID_NONE && (pri == 0 ||
473 	    dsp->ds_dlp->dl_tagmode == LINK_TAGMODE_VLANONLY)) || !is_ethernet)
474 		return (mp);
475 
476 	/*
477 	 * Fill in the tag information.
478 	 */
479 	ASSERT(MBLKL(mp) == sizeof (struct ether_header));
480 	if (extra_len != 0) {
481 		mp->b_wptr += extra_len;
482 		evhp = (struct ether_vlan_header *)mp->b_rptr;
483 		evhp->ether_tci = htons(VLAN_TCI(pri, ETHER_CFI, vid));
484 		evhp->ether_type = htons(sap);
485 	} else {
486 		/*
487 		 * The stream is ETHERTYPE_VLAN listener, so its VLAN tag is
488 		 * in the payload. Update the priority.
489 		 */
490 		struct ether_vlan_extinfo *extinfo;
491 		size_t len = sizeof (struct ether_vlan_extinfo);
492 
493 		ASSERT(sap == ETHERTYPE_VLAN);
494 		ASSERT(payload != NULL);
495 
496 		if ((DB_REF(payload) > 1) || (MBLKL(payload) < len)) {
497 			mblk_t *newmp;
498 
499 			/*
500 			 * Because some DLS consumers only check the db_ref
501 			 * count of the first mblk, we pullup 'payload' into
502 			 * a single mblk.
503 			 */
504 			newmp = msgpullup(payload, -1);
505 			if ((newmp == NULL) || (MBLKL(newmp) < len)) {
506 				freemsg(newmp);
507 				freemsg(mp);
508 				return (NULL);
509 			} else {
510 				freemsg(payload);
511 				*payloadp = payload = newmp;
512 			}
513 		}
514 
515 		extinfo = (struct ether_vlan_extinfo *)payload->b_rptr;
516 		extinfo->ether_tci = htons(VLAN_TCI(pri, ETHER_CFI,
517 		    VLAN_ID(ntohs(extinfo->ether_tci))));
518 	}
519 	return (mp);
520 }
521 
522 void
523 dls_rx_set(dld_str_t *dsp, dls_rx_t rx, void *arg)
524 {
525 	mutex_enter(&dsp->ds_lock);
526 	dsp->ds_rx = rx;
527 	dsp->ds_rx_arg = arg;
528 	mutex_exit(&dsp->ds_lock);
529 }
530 
531 static boolean_t
532 dls_accept_common(dld_str_t *dsp, mac_header_info_t *mhip, dls_rx_t *ds_rx,
533     void **ds_rx_arg, boolean_t promisc, boolean_t promisc_loopback)
534 {
535 	dls_multicst_addr_t	*dmap;
536 	size_t			addr_length = dsp->ds_mip->mi_addr_length;
537 
538 	/*
539 	 * We must not accept packets if the dld_str_t is not marked as bound
540 	 * or is being removed.
541 	 */
542 	if (dsp->ds_dlstate != DL_IDLE)
543 		goto refuse;
544 
545 	if (dsp->ds_promisc != 0) {
546 		/*
547 		 * Filter out packets that arrived from the data path
548 		 * (i_dls_link_rx) when promisc mode is on. We need to correlate
549 		 * the ds_promisc flags with the mac header destination type. If
550 		 * only DLS_PROMISC_MULTI is enabled, we need to only reject
551 		 * multicast packets as those are the only ones which filter up
552 		 * the promiscuous path. If we have DLS_PROMISC_PHYS or
553 		 * DLS_PROMISC_SAP set, then we know that we'll be seeing
554 		 * everything, so we should drop it now.
555 		 */
556 		if (!promisc && !(dsp->ds_promisc == DLS_PROMISC_MULTI &&
557 		    mhip->mhi_dsttype != MAC_ADDRTYPE_MULTICAST))
558 			goto refuse;
559 		/*
560 		 * If the dls_impl_t is in 'all physical' mode then
561 		 * always accept.
562 		 */
563 		if (dsp->ds_promisc & DLS_PROMISC_PHYS)
564 			goto accept;
565 
566 		/*
567 		 * Loopback packets i.e. packets sent out by DLS on a given
568 		 * mac end point, will be accepted back by DLS on loopback
569 		 * from the mac, only in the 'all physical' mode which has been
570 		 * covered by the previous check above
571 		 */
572 		if (promisc_loopback)
573 			goto refuse;
574 	}
575 
576 	switch (mhip->mhi_dsttype) {
577 	case MAC_ADDRTYPE_UNICAST:
578 	case MAC_ADDRTYPE_BROADCAST:
579 		/*
580 		 * We can accept unicast and broadcast packets because
581 		 * filtering is already done by the mac layer.
582 		 */
583 		goto accept;
584 	case MAC_ADDRTYPE_MULTICAST:
585 		/*
586 		 * Additional filtering is needed for multicast addresses
587 		 * because different streams may be interested in different
588 		 * addresses.
589 		 */
590 		if (dsp->ds_promisc & DLS_PROMISC_MULTI)
591 			goto accept;
592 
593 		rw_enter(&dsp->ds_rw_lock, RW_READER);
594 		for (dmap = dsp->ds_dmap; dmap != NULL;
595 		    dmap = dmap->dma_nextp) {
596 			if (memcmp(mhip->mhi_daddr, dmap->dma_addr,
597 			    addr_length) == 0) {
598 				rw_exit(&dsp->ds_rw_lock);
599 				goto accept;
600 			}
601 		}
602 		rw_exit(&dsp->ds_rw_lock);
603 		break;
604 	}
605 
606 refuse:
607 	return (B_FALSE);
608 
609 accept:
610 	/*
611 	 * the returned ds_rx and ds_rx_arg will always be in sync.
612 	 */
613 	mutex_enter(&dsp->ds_lock);
614 	*ds_rx = dsp->ds_rx;
615 	*ds_rx_arg = dsp->ds_rx_arg;
616 	mutex_exit(&dsp->ds_lock);
617 
618 	return (B_TRUE);
619 }
620 
621 /* ARGSUSED */
622 boolean_t
623 dls_accept(dld_str_t *dsp, mac_header_info_t *mhip, dls_rx_t *ds_rx,
624     void **ds_rx_arg)
625 {
626 	return (dls_accept_common(dsp, mhip, ds_rx, ds_rx_arg, B_FALSE,
627 	    B_FALSE));
628 }
629 
630 boolean_t
631 dls_accept_promisc(dld_str_t *dsp, mac_header_info_t *mhip, dls_rx_t *ds_rx,
632     void **ds_rx_arg, boolean_t loopback)
633 {
634 	return (dls_accept_common(dsp, mhip, ds_rx, ds_rx_arg, B_TRUE,
635 	    loopback));
636 }
637 
638 int
639 dls_mac_active_set(dls_link_t *dlp)
640 {
641 	int err = 0;
642 
643 	/*
644 	 * First client; add the primary unicast address.
645 	 */
646 	if (dlp->dl_nactive == 0) {
647 		/*
648 		 * First client; add the primary unicast address.
649 		 */
650 		mac_diag_t diag;
651 
652 		/* request the primary MAC address */
653 		if ((err = mac_unicast_add(dlp->dl_mch, NULL,
654 		    MAC_UNICAST_PRIMARY | MAC_UNICAST_TAG_DISABLE |
655 		    MAC_UNICAST_DISABLE_TX_VID_CHECK, &dlp->dl_mah, 0,
656 		    &diag)) != 0) {
657 			return (err);
658 		}
659 
660 		/*
661 		 * Set the function to start receiving packets.
662 		 */
663 		mac_rx_set(dlp->dl_mch, i_dls_link_rx, dlp);
664 	}
665 	dlp->dl_nactive++;
666 	return (0);
667 }
668 
669 void
670 dls_mac_active_clear(dls_link_t *dlp)
671 {
672 	if (--dlp->dl_nactive == 0) {
673 		ASSERT(dlp->dl_mah != NULL);
674 		(void) mac_unicast_remove(dlp->dl_mch, dlp->dl_mah);
675 		dlp->dl_mah = NULL;
676 		mac_rx_clear(dlp->dl_mch);
677 	}
678 }
679 
680 int
681 dls_active_set(dld_str_t *dsp)
682 {
683 	int err = 0;
684 
685 	ASSERT(MAC_PERIM_HELD(dsp->ds_mh));
686 
687 	if (dsp->ds_passivestate == DLD_PASSIVE)
688 		return (0);
689 
690 	/* If we're already active, then there's nothing more to do. */
691 	if ((dsp->ds_nactive == 0) &&
692 	    ((err = dls_mac_active_set(dsp->ds_dlp)) != 0)) {
693 		/* except for ENXIO all other errors are mapped to EBUSY */
694 		if (err != ENXIO)
695 			return (EBUSY);
696 		return (err);
697 	}
698 
699 	dsp->ds_passivestate = DLD_ACTIVE;
700 	dsp->ds_nactive++;
701 	return (0);
702 }
703 
704 /*
705  * Note that dls_active_set() is called whenever an active operation
706  * (DL_BIND_REQ, DL_ENABMULTI_REQ ...) is processed and
707  * dls_active_clear(dsp, B_FALSE) is called whenever the active operation
708  * is being undone (DL_UNBIND_REQ, DL_DISABMULTI_REQ ...). In some cases,
709  * a stream is closed without every active operation being undone and we
710  * need to clear all the "active" states by calling
711  * dls_active_clear(dsp, B_TRUE).
712  */
713 void
714 dls_active_clear(dld_str_t *dsp, boolean_t all)
715 {
716 	ASSERT(MAC_PERIM_HELD(dsp->ds_mh));
717 
718 	if (dsp->ds_passivestate == DLD_PASSIVE)
719 		return;
720 
721 	if (all && dsp->ds_nactive == 0)
722 		return;
723 
724 	ASSERT(dsp->ds_nactive > 0);
725 
726 	dsp->ds_nactive -= (all ? dsp->ds_nactive : 1);
727 	if (dsp->ds_nactive != 0)
728 		return;
729 
730 	ASSERT(dsp->ds_passivestate == DLD_ACTIVE);
731 	dls_mac_active_clear(dsp->ds_dlp);
732 	dsp->ds_passivestate = DLD_UNINITIALIZED;
733 }
734