xref: /openbmc/linux/net/mac80211/iface.c (revision 9ac8d3fb)
1 /*
2  * Interface handling (except master interface)
3  *
4  * Copyright 2002-2005, Instant802 Networks, Inc.
5  * Copyright 2005-2006, Devicescape Software, Inc.
6  * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
7  * Copyright 2008, Johannes Berg <johannes@sipsolutions.net>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 #include <linux/kernel.h>
14 #include <linux/if_arp.h>
15 #include <linux/netdevice.h>
16 #include <linux/rtnetlink.h>
17 #include <net/mac80211.h>
18 #include "ieee80211_i.h"
19 #include "sta_info.h"
20 #include "debugfs_netdev.h"
21 #include "mesh.h"
22 #include "led.h"
23 
24 static int ieee80211_change_mtu(struct net_device *dev, int new_mtu)
25 {
26 	int meshhdrlen;
27 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
28 
29 	meshhdrlen = (sdata->vif.type == NL80211_IFTYPE_MESH_POINT) ? 5 : 0;
30 
31 	/* FIX: what would be proper limits for MTU?
32 	 * This interface uses 802.3 frames. */
33 	if (new_mtu < 256 ||
34 	    new_mtu > IEEE80211_MAX_DATA_LEN - 24 - 6 - meshhdrlen) {
35 		return -EINVAL;
36 	}
37 
38 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
39 	printk(KERN_DEBUG "%s: setting MTU %d\n", dev->name, new_mtu);
40 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
41 	dev->mtu = new_mtu;
42 	return 0;
43 }
44 
45 static inline int identical_mac_addr_allowed(int type1, int type2)
46 {
47 	return type1 == NL80211_IFTYPE_MONITOR ||
48 		type2 == NL80211_IFTYPE_MONITOR ||
49 		(type1 == NL80211_IFTYPE_AP && type2 == NL80211_IFTYPE_WDS) ||
50 		(type1 == NL80211_IFTYPE_WDS &&
51 			(type2 == NL80211_IFTYPE_WDS ||
52 			 type2 == NL80211_IFTYPE_AP)) ||
53 		(type1 == NL80211_IFTYPE_AP && type2 == NL80211_IFTYPE_AP_VLAN) ||
54 		(type1 == NL80211_IFTYPE_AP_VLAN &&
55 			(type2 == NL80211_IFTYPE_AP ||
56 			 type2 == NL80211_IFTYPE_AP_VLAN));
57 }
58 
59 static int ieee80211_open(struct net_device *dev)
60 {
61 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
62 	struct ieee80211_sub_if_data *nsdata;
63 	struct ieee80211_local *local = sdata->local;
64 	struct sta_info *sta;
65 	struct ieee80211_if_init_conf conf;
66 	u32 changed = 0;
67 	int res;
68 	bool need_hw_reconfig = 0;
69 	u8 null_addr[ETH_ALEN] = {0};
70 
71 	/* fail early if user set an invalid address */
72 	if (compare_ether_addr(dev->dev_addr, null_addr) &&
73 	    !is_valid_ether_addr(dev->dev_addr))
74 		return -EADDRNOTAVAIL;
75 
76 	/* we hold the RTNL here so can safely walk the list */
77 	list_for_each_entry(nsdata, &local->interfaces, list) {
78 		struct net_device *ndev = nsdata->dev;
79 
80 		if (ndev != dev && netif_running(ndev)) {
81 			/*
82 			 * Allow only a single IBSS interface to be up at any
83 			 * time. This is restricted because beacon distribution
84 			 * cannot work properly if both are in the same IBSS.
85 			 *
86 			 * To remove this restriction we'd have to disallow them
87 			 * from setting the same SSID on different IBSS interfaces
88 			 * belonging to the same hardware. Then, however, we're
89 			 * faced with having to adopt two different TSF timers...
90 			 */
91 			if (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
92 			    nsdata->vif.type == NL80211_IFTYPE_ADHOC)
93 				return -EBUSY;
94 
95 			/*
96 			 * The remaining checks are only performed for interfaces
97 			 * with the same MAC address.
98 			 */
99 			if (compare_ether_addr(dev->dev_addr, ndev->dev_addr))
100 				continue;
101 
102 			/*
103 			 * check whether it may have the same address
104 			 */
105 			if (!identical_mac_addr_allowed(sdata->vif.type,
106 							nsdata->vif.type))
107 				return -ENOTUNIQ;
108 
109 			/*
110 			 * can only add VLANs to enabled APs
111 			 */
112 			if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
113 			    nsdata->vif.type == NL80211_IFTYPE_AP)
114 				sdata->bss = &nsdata->u.ap;
115 		}
116 	}
117 
118 	switch (sdata->vif.type) {
119 	case NL80211_IFTYPE_WDS:
120 		if (!is_valid_ether_addr(sdata->u.wds.remote_addr))
121 			return -ENOLINK;
122 		break;
123 	case NL80211_IFTYPE_AP_VLAN:
124 		if (!sdata->bss)
125 			return -ENOLINK;
126 		list_add(&sdata->u.vlan.list, &sdata->bss->vlans);
127 		break;
128 	case NL80211_IFTYPE_AP:
129 		sdata->bss = &sdata->u.ap;
130 		break;
131 	case NL80211_IFTYPE_MESH_POINT:
132 		if (!ieee80211_vif_is_mesh(&sdata->vif))
133 			break;
134 		/* mesh ifaces must set allmulti to forward mcast traffic */
135 		atomic_inc(&local->iff_allmultis);
136 		break;
137 	case NL80211_IFTYPE_STATION:
138 	case NL80211_IFTYPE_MONITOR:
139 	case NL80211_IFTYPE_ADHOC:
140 		/* no special treatment */
141 		break;
142 	case NL80211_IFTYPE_UNSPECIFIED:
143 	case __NL80211_IFTYPE_AFTER_LAST:
144 		/* cannot happen */
145 		WARN_ON(1);
146 		break;
147 	}
148 
149 	if (local->open_count == 0) {
150 		res = 0;
151 		if (local->ops->start)
152 			res = local->ops->start(local_to_hw(local));
153 		if (res)
154 			goto err_del_bss;
155 		need_hw_reconfig = 1;
156 		ieee80211_led_radio(local, local->hw.conf.radio_enabled);
157 	}
158 
159 	/*
160 	 * Check all interfaces and copy the hopefully now-present
161 	 * MAC address to those that have the special null one.
162 	 */
163 	list_for_each_entry(nsdata, &local->interfaces, list) {
164 		struct net_device *ndev = nsdata->dev;
165 
166 		/*
167 		 * No need to check netif_running since we do not allow
168 		 * it to start up with this invalid address.
169 		 */
170 		if (compare_ether_addr(null_addr, ndev->dev_addr) == 0)
171 			memcpy(ndev->dev_addr,
172 			       local->hw.wiphy->perm_addr,
173 			       ETH_ALEN);
174 	}
175 
176 	if (compare_ether_addr(null_addr, local->mdev->dev_addr) == 0)
177 		memcpy(local->mdev->dev_addr, local->hw.wiphy->perm_addr,
178 		       ETH_ALEN);
179 
180 	/*
181 	 * Validate the MAC address for this device.
182 	 */
183 	if (!is_valid_ether_addr(dev->dev_addr)) {
184 		if (!local->open_count && local->ops->stop)
185 			local->ops->stop(local_to_hw(local));
186 		return -EADDRNOTAVAIL;
187 	}
188 
189 	switch (sdata->vif.type) {
190 	case NL80211_IFTYPE_AP_VLAN:
191 		/* no need to tell driver */
192 		break;
193 	case NL80211_IFTYPE_MONITOR:
194 		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {
195 			local->cooked_mntrs++;
196 			break;
197 		}
198 
199 		/* must be before the call to ieee80211_configure_filter */
200 		local->monitors++;
201 		if (local->monitors == 1)
202 			local->hw.conf.flags |= IEEE80211_CONF_RADIOTAP;
203 
204 		if (sdata->u.mntr_flags & MONITOR_FLAG_FCSFAIL)
205 			local->fif_fcsfail++;
206 		if (sdata->u.mntr_flags & MONITOR_FLAG_PLCPFAIL)
207 			local->fif_plcpfail++;
208 		if (sdata->u.mntr_flags & MONITOR_FLAG_CONTROL)
209 			local->fif_control++;
210 		if (sdata->u.mntr_flags & MONITOR_FLAG_OTHER_BSS)
211 			local->fif_other_bss++;
212 
213 		netif_addr_lock_bh(local->mdev);
214 		ieee80211_configure_filter(local);
215 		netif_addr_unlock_bh(local->mdev);
216 		break;
217 	case NL80211_IFTYPE_STATION:
218 	case NL80211_IFTYPE_ADHOC:
219 		sdata->u.sta.flags &= ~IEEE80211_STA_PREV_BSSID_SET;
220 		/* fall through */
221 	default:
222 		conf.vif = &sdata->vif;
223 		conf.type = sdata->vif.type;
224 		conf.mac_addr = dev->dev_addr;
225 		res = local->ops->add_interface(local_to_hw(local), &conf);
226 		if (res)
227 			goto err_stop;
228 
229 		if (ieee80211_vif_is_mesh(&sdata->vif))
230 			ieee80211_start_mesh(sdata);
231 		changed |= ieee80211_reset_erp_info(sdata);
232 		ieee80211_bss_info_change_notify(sdata, changed);
233 		ieee80211_enable_keys(sdata);
234 
235 		if (sdata->vif.type == NL80211_IFTYPE_STATION &&
236 		    !(sdata->flags & IEEE80211_SDATA_USERSPACE_MLME))
237 			netif_carrier_off(dev);
238 		else
239 			netif_carrier_on(dev);
240 	}
241 
242 	if (sdata->vif.type == NL80211_IFTYPE_WDS) {
243 		/* Create STA entry for the WDS peer */
244 		sta = sta_info_alloc(sdata, sdata->u.wds.remote_addr,
245 				     GFP_KERNEL);
246 		if (!sta) {
247 			res = -ENOMEM;
248 			goto err_del_interface;
249 		}
250 
251 		/* no locking required since STA is not live yet */
252 		sta->flags |= WLAN_STA_AUTHORIZED;
253 
254 		res = sta_info_insert(sta);
255 		if (res) {
256 			/* STA has been freed */
257 			goto err_del_interface;
258 		}
259 	}
260 
261 	if (local->open_count == 0) {
262 		res = dev_open(local->mdev);
263 		WARN_ON(res);
264 		if (res)
265 			goto err_del_interface;
266 		tasklet_enable(&local->tx_pending_tasklet);
267 		tasklet_enable(&local->tasklet);
268 	}
269 
270 	/*
271 	 * set_multicast_list will be invoked by the networking core
272 	 * which will check whether any increments here were done in
273 	 * error and sync them down to the hardware as filter flags.
274 	 */
275 	if (sdata->flags & IEEE80211_SDATA_ALLMULTI)
276 		atomic_inc(&local->iff_allmultis);
277 
278 	if (sdata->flags & IEEE80211_SDATA_PROMISC)
279 		atomic_inc(&local->iff_promiscs);
280 
281 	local->open_count++;
282 	if (need_hw_reconfig) {
283 		ieee80211_hw_config(local);
284 		/*
285 		 * set default queue parameters so drivers don't
286 		 * need to initialise the hardware if the hardware
287 		 * doesn't start up with sane defaults
288 		 */
289 		ieee80211_set_wmm_default(sdata);
290 	}
291 
292 	/*
293 	 * ieee80211_sta_work is disabled while network interface
294 	 * is down. Therefore, some configuration changes may not
295 	 * yet be effective. Trigger execution of ieee80211_sta_work
296 	 * to fix this.
297 	 */
298 	if (sdata->vif.type == NL80211_IFTYPE_STATION ||
299 	    sdata->vif.type == NL80211_IFTYPE_ADHOC) {
300 		struct ieee80211_if_sta *ifsta = &sdata->u.sta;
301 		queue_work(local->hw.workqueue, &ifsta->work);
302 	}
303 
304 	netif_tx_start_all_queues(dev);
305 
306 	return 0;
307  err_del_interface:
308 	local->ops->remove_interface(local_to_hw(local), &conf);
309  err_stop:
310 	if (!local->open_count && local->ops->stop)
311 		local->ops->stop(local_to_hw(local));
312  err_del_bss:
313 	sdata->bss = NULL;
314 	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
315 		list_del(&sdata->u.vlan.list);
316 	return res;
317 }
318 
319 static int ieee80211_stop(struct net_device *dev)
320 {
321 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
322 	struct ieee80211_local *local = sdata->local;
323 	struct ieee80211_if_init_conf conf;
324 	struct sta_info *sta;
325 
326 	/*
327 	 * Stop TX on this interface first.
328 	 */
329 	netif_tx_stop_all_queues(dev);
330 
331 	/*
332 	 * Now delete all active aggregation sessions.
333 	 */
334 	rcu_read_lock();
335 
336 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
337 		if (sta->sdata == sdata)
338 			ieee80211_sta_tear_down_BA_sessions(sdata,
339 							    sta->sta.addr);
340 	}
341 
342 	rcu_read_unlock();
343 
344 	/*
345 	 * Remove all stations associated with this interface.
346 	 *
347 	 * This must be done before calling ops->remove_interface()
348 	 * because otherwise we can later invoke ops->sta_notify()
349 	 * whenever the STAs are removed, and that invalidates driver
350 	 * assumptions about always getting a vif pointer that is valid
351 	 * (because if we remove a STA after ops->remove_interface()
352 	 * the driver will have removed the vif info already!)
353 	 *
354 	 * We could relax this and only unlink the stations from the
355 	 * hash table and list but keep them on a per-sdata list that
356 	 * will be inserted back again when the interface is brought
357 	 * up again, but I don't currently see a use case for that,
358 	 * except with WDS which gets a STA entry created when it is
359 	 * brought up.
360 	 */
361 	sta_info_flush(local, sdata);
362 
363 	/*
364 	 * Don't count this interface for promisc/allmulti while it
365 	 * is down. dev_mc_unsync() will invoke set_multicast_list
366 	 * on the master interface which will sync these down to the
367 	 * hardware as filter flags.
368 	 */
369 	if (sdata->flags & IEEE80211_SDATA_ALLMULTI)
370 		atomic_dec(&local->iff_allmultis);
371 
372 	if (sdata->flags & IEEE80211_SDATA_PROMISC)
373 		atomic_dec(&local->iff_promiscs);
374 
375 	dev_mc_unsync(local->mdev, dev);
376 
377 	/* APs need special treatment */
378 	if (sdata->vif.type == NL80211_IFTYPE_AP) {
379 		struct ieee80211_sub_if_data *vlan, *tmp;
380 		struct beacon_data *old_beacon = sdata->u.ap.beacon;
381 
382 		/* remove beacon */
383 		rcu_assign_pointer(sdata->u.ap.beacon, NULL);
384 		synchronize_rcu();
385 		kfree(old_beacon);
386 
387 		/* down all dependent devices, that is VLANs */
388 		list_for_each_entry_safe(vlan, tmp, &sdata->u.ap.vlans,
389 					 u.vlan.list)
390 			dev_close(vlan->dev);
391 		WARN_ON(!list_empty(&sdata->u.ap.vlans));
392 	}
393 
394 	local->open_count--;
395 
396 	switch (sdata->vif.type) {
397 	case NL80211_IFTYPE_AP_VLAN:
398 		list_del(&sdata->u.vlan.list);
399 		/* no need to tell driver */
400 		break;
401 	case NL80211_IFTYPE_MONITOR:
402 		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {
403 			local->cooked_mntrs--;
404 			break;
405 		}
406 
407 		local->monitors--;
408 		if (local->monitors == 0)
409 			local->hw.conf.flags &= ~IEEE80211_CONF_RADIOTAP;
410 
411 		if (sdata->u.mntr_flags & MONITOR_FLAG_FCSFAIL)
412 			local->fif_fcsfail--;
413 		if (sdata->u.mntr_flags & MONITOR_FLAG_PLCPFAIL)
414 			local->fif_plcpfail--;
415 		if (sdata->u.mntr_flags & MONITOR_FLAG_CONTROL)
416 			local->fif_control--;
417 		if (sdata->u.mntr_flags & MONITOR_FLAG_OTHER_BSS)
418 			local->fif_other_bss--;
419 
420 		netif_addr_lock_bh(local->mdev);
421 		ieee80211_configure_filter(local);
422 		netif_addr_unlock_bh(local->mdev);
423 		break;
424 	case NL80211_IFTYPE_STATION:
425 	case NL80211_IFTYPE_ADHOC:
426 		sdata->u.sta.state = IEEE80211_STA_MLME_DISABLED;
427 		memset(sdata->u.sta.bssid, 0, ETH_ALEN);
428 		del_timer_sync(&sdata->u.sta.timer);
429 		/*
430 		 * If the timer fired while we waited for it, it will have
431 		 * requeued the work. Now the work will be running again
432 		 * but will not rearm the timer again because it checks
433 		 * whether the interface is running, which, at this point,
434 		 * it no longer is.
435 		 */
436 		cancel_work_sync(&sdata->u.sta.work);
437 		/*
438 		 * When we get here, the interface is marked down.
439 		 * Call synchronize_rcu() to wait for the RX path
440 		 * should it be using the interface and enqueuing
441 		 * frames at this very time on another CPU.
442 		 */
443 		synchronize_rcu();
444 		skb_queue_purge(&sdata->u.sta.skb_queue);
445 
446 		sdata->u.sta.flags &= ~IEEE80211_STA_PRIVACY_INVOKED;
447 		kfree(sdata->u.sta.extra_ie);
448 		sdata->u.sta.extra_ie = NULL;
449 		sdata->u.sta.extra_ie_len = 0;
450 		/* fall through */
451 	case NL80211_IFTYPE_MESH_POINT:
452 		if (ieee80211_vif_is_mesh(&sdata->vif)) {
453 			/* allmulti is always set on mesh ifaces */
454 			atomic_dec(&local->iff_allmultis);
455 			ieee80211_stop_mesh(sdata);
456 		}
457 		/* fall through */
458 	default:
459 		if (local->scan_sdata == sdata) {
460 			if (!local->ops->hw_scan)
461 				cancel_delayed_work_sync(&local->scan_work);
462 			/*
463 			 * The software scan can no longer run now, so we can
464 			 * clear out the scan_sdata reference. However, the
465 			 * hardware scan may still be running. The complete
466 			 * function must be prepared to handle a NULL value.
467 			 */
468 			local->scan_sdata = NULL;
469 			/*
470 			 * The memory barrier guarantees that another CPU
471 			 * that is hardware-scanning will now see the fact
472 			 * that this interface is gone.
473 			 */
474 			smp_mb();
475 			/*
476 			 * If software scanning, complete the scan but since
477 			 * the scan_sdata is NULL already don't send out a
478 			 * scan event to userspace -- the scan is incomplete.
479 			 */
480 			if (local->sw_scanning)
481 				ieee80211_scan_completed(&local->hw);
482 		}
483 
484 		conf.vif = &sdata->vif;
485 		conf.type = sdata->vif.type;
486 		conf.mac_addr = dev->dev_addr;
487 		/* disable all keys for as long as this netdev is down */
488 		ieee80211_disable_keys(sdata);
489 		local->ops->remove_interface(local_to_hw(local), &conf);
490 	}
491 
492 	sdata->bss = NULL;
493 
494 	if (local->open_count == 0) {
495 		if (netif_running(local->mdev))
496 			dev_close(local->mdev);
497 
498 		if (local->ops->stop)
499 			local->ops->stop(local_to_hw(local));
500 
501 		ieee80211_led_radio(local, 0);
502 
503 		flush_workqueue(local->hw.workqueue);
504 
505 		tasklet_disable(&local->tx_pending_tasklet);
506 		tasklet_disable(&local->tasklet);
507 	}
508 
509 	return 0;
510 }
511 
512 static void ieee80211_set_multicast_list(struct net_device *dev)
513 {
514 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
515 	struct ieee80211_local *local = sdata->local;
516 	int allmulti, promisc, sdata_allmulti, sdata_promisc;
517 
518 	allmulti = !!(dev->flags & IFF_ALLMULTI);
519 	promisc = !!(dev->flags & IFF_PROMISC);
520 	sdata_allmulti = !!(sdata->flags & IEEE80211_SDATA_ALLMULTI);
521 	sdata_promisc = !!(sdata->flags & IEEE80211_SDATA_PROMISC);
522 
523 	if (allmulti != sdata_allmulti) {
524 		if (dev->flags & IFF_ALLMULTI)
525 			atomic_inc(&local->iff_allmultis);
526 		else
527 			atomic_dec(&local->iff_allmultis);
528 		sdata->flags ^= IEEE80211_SDATA_ALLMULTI;
529 	}
530 
531 	if (promisc != sdata_promisc) {
532 		if (dev->flags & IFF_PROMISC)
533 			atomic_inc(&local->iff_promiscs);
534 		else
535 			atomic_dec(&local->iff_promiscs);
536 		sdata->flags ^= IEEE80211_SDATA_PROMISC;
537 	}
538 
539 	dev_mc_sync(local->mdev, dev);
540 }
541 
542 static void ieee80211_if_setup(struct net_device *dev)
543 {
544 	ether_setup(dev);
545 	dev->hard_start_xmit = ieee80211_subif_start_xmit;
546 	dev->wireless_handlers = &ieee80211_iw_handler_def;
547 	dev->set_multicast_list = ieee80211_set_multicast_list;
548 	dev->change_mtu = ieee80211_change_mtu;
549 	dev->open = ieee80211_open;
550 	dev->stop = ieee80211_stop;
551 	dev->destructor = free_netdev;
552 	/* we will validate the address ourselves in ->open */
553 	dev->validate_addr = NULL;
554 }
555 /*
556  * Called when the netdev is removed or, by the code below, before
557  * the interface type changes.
558  */
559 static void ieee80211_teardown_sdata(struct net_device *dev)
560 {
561 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
562 	struct ieee80211_local *local = sdata->local;
563 	struct beacon_data *beacon;
564 	struct sk_buff *skb;
565 	int flushed;
566 	int i;
567 
568 	/* free extra data */
569 	ieee80211_free_keys(sdata);
570 
571 	ieee80211_debugfs_remove_netdev(sdata);
572 
573 	for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++)
574 		__skb_queue_purge(&sdata->fragments[i].skb_list);
575 	sdata->fragment_next = 0;
576 
577 	switch (sdata->vif.type) {
578 	case NL80211_IFTYPE_AP:
579 		beacon = sdata->u.ap.beacon;
580 		rcu_assign_pointer(sdata->u.ap.beacon, NULL);
581 		synchronize_rcu();
582 		kfree(beacon);
583 
584 		while ((skb = skb_dequeue(&sdata->u.ap.ps_bc_buf))) {
585 			local->total_ps_buffered--;
586 			dev_kfree_skb(skb);
587 		}
588 
589 		break;
590 	case NL80211_IFTYPE_MESH_POINT:
591 		if (ieee80211_vif_is_mesh(&sdata->vif))
592 			mesh_rmc_free(sdata);
593 		break;
594 	case NL80211_IFTYPE_STATION:
595 	case NL80211_IFTYPE_ADHOC:
596 		kfree(sdata->u.sta.extra_ie);
597 		kfree(sdata->u.sta.assocreq_ies);
598 		kfree(sdata->u.sta.assocresp_ies);
599 		kfree_skb(sdata->u.sta.probe_resp);
600 		break;
601 	case NL80211_IFTYPE_WDS:
602 	case NL80211_IFTYPE_AP_VLAN:
603 	case NL80211_IFTYPE_MONITOR:
604 		break;
605 	case NL80211_IFTYPE_UNSPECIFIED:
606 	case __NL80211_IFTYPE_AFTER_LAST:
607 		BUG();
608 		break;
609 	}
610 
611 	flushed = sta_info_flush(local, sdata);
612 	WARN_ON(flushed);
613 }
614 
615 /*
616  * Helper function to initialise an interface to a specific type.
617  */
618 static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata,
619 				  enum nl80211_iftype type)
620 {
621 	/* clear type-dependent union */
622 	memset(&sdata->u, 0, sizeof(sdata->u));
623 
624 	/* and set some type-dependent values */
625 	sdata->vif.type = type;
626 	sdata->dev->hard_start_xmit = ieee80211_subif_start_xmit;
627 	sdata->wdev.iftype = type;
628 
629 	/* only monitor differs */
630 	sdata->dev->type = ARPHRD_ETHER;
631 
632 	switch (type) {
633 	case NL80211_IFTYPE_AP:
634 		skb_queue_head_init(&sdata->u.ap.ps_bc_buf);
635 		INIT_LIST_HEAD(&sdata->u.ap.vlans);
636 		break;
637 	case NL80211_IFTYPE_STATION:
638 	case NL80211_IFTYPE_ADHOC:
639 		ieee80211_sta_setup_sdata(sdata);
640 		break;
641 	case NL80211_IFTYPE_MESH_POINT:
642 		if (ieee80211_vif_is_mesh(&sdata->vif))
643 			ieee80211_mesh_init_sdata(sdata);
644 		break;
645 	case NL80211_IFTYPE_MONITOR:
646 		sdata->dev->type = ARPHRD_IEEE80211_RADIOTAP;
647 		sdata->dev->hard_start_xmit = ieee80211_monitor_start_xmit;
648 		sdata->u.mntr_flags = MONITOR_FLAG_CONTROL |
649 				      MONITOR_FLAG_OTHER_BSS;
650 		break;
651 	case NL80211_IFTYPE_WDS:
652 	case NL80211_IFTYPE_AP_VLAN:
653 		break;
654 	case NL80211_IFTYPE_UNSPECIFIED:
655 	case __NL80211_IFTYPE_AFTER_LAST:
656 		BUG();
657 		break;
658 	}
659 
660 	ieee80211_debugfs_add_netdev(sdata);
661 }
662 
663 int ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
664 			     enum nl80211_iftype type)
665 {
666 	ASSERT_RTNL();
667 
668 	if (type == sdata->vif.type)
669 		return 0;
670 
671 	/*
672 	 * We could, here, on changes between IBSS/STA/MESH modes,
673 	 * invoke an MLME function instead that disassociates etc.
674 	 * and goes into the requested mode.
675 	 */
676 
677 	if (netif_running(sdata->dev))
678 		return -EBUSY;
679 
680 	/* Purge and reset type-dependent state. */
681 	ieee80211_teardown_sdata(sdata->dev);
682 	ieee80211_setup_sdata(sdata, type);
683 
684 	/* reset some values that shouldn't be kept across type changes */
685 	sdata->bss_conf.basic_rates =
686 		ieee80211_mandatory_rates(sdata->local,
687 			sdata->local->hw.conf.channel->band);
688 	sdata->drop_unencrypted = 0;
689 
690 	return 0;
691 }
692 
693 int ieee80211_if_add(struct ieee80211_local *local, const char *name,
694 		     struct net_device **new_dev, enum nl80211_iftype type,
695 		     struct vif_params *params)
696 {
697 	struct net_device *ndev;
698 	struct ieee80211_sub_if_data *sdata = NULL;
699 	int ret, i;
700 
701 	ASSERT_RTNL();
702 
703 	ndev = alloc_netdev(sizeof(*sdata) + local->hw.vif_data_size,
704 			    name, ieee80211_if_setup);
705 	if (!ndev)
706 		return -ENOMEM;
707 
708 	ndev->needed_headroom = local->tx_headroom +
709 				4*6 /* four MAC addresses */
710 				+ 2 + 2 + 2 + 2 /* ctl, dur, seq, qos */
711 				+ 6 /* mesh */
712 				+ 8 /* rfc1042/bridge tunnel */
713 				- ETH_HLEN /* ethernet hard_header_len */
714 				+ IEEE80211_ENCRYPT_HEADROOM;
715 	ndev->needed_tailroom = IEEE80211_ENCRYPT_TAILROOM;
716 
717 	ret = dev_alloc_name(ndev, ndev->name);
718 	if (ret < 0)
719 		goto fail;
720 
721 	memcpy(ndev->dev_addr, local->hw.wiphy->perm_addr, ETH_ALEN);
722 	SET_NETDEV_DEV(ndev, wiphy_dev(local->hw.wiphy));
723 
724 	/* don't use IEEE80211_DEV_TO_SUB_IF because it checks too much */
725 	sdata = netdev_priv(ndev);
726 	ndev->ieee80211_ptr = &sdata->wdev;
727 
728 	/* initialise type-independent data */
729 	sdata->wdev.wiphy = local->hw.wiphy;
730 	sdata->local = local;
731 	sdata->dev = ndev;
732 
733 	for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++)
734 		skb_queue_head_init(&sdata->fragments[i].skb_list);
735 
736 	INIT_LIST_HEAD(&sdata->key_list);
737 
738 	sdata->force_unicast_rateidx = -1;
739 	sdata->max_ratectrl_rateidx = -1;
740 
741 	/* setup type-dependent data */
742 	ieee80211_setup_sdata(sdata, type);
743 
744 	ret = register_netdevice(ndev);
745 	if (ret)
746 		goto fail;
747 
748 	ndev->uninit = ieee80211_teardown_sdata;
749 
750 	if (ieee80211_vif_is_mesh(&sdata->vif) &&
751 	    params && params->mesh_id_len)
752 		ieee80211_sdata_set_mesh_id(sdata,
753 					    params->mesh_id_len,
754 					    params->mesh_id);
755 
756 	list_add_tail_rcu(&sdata->list, &local->interfaces);
757 
758 	if (new_dev)
759 		*new_dev = ndev;
760 
761 	return 0;
762 
763  fail:
764 	free_netdev(ndev);
765 	return ret;
766 }
767 
768 void ieee80211_if_remove(struct ieee80211_sub_if_data *sdata)
769 {
770 	ASSERT_RTNL();
771 
772 	list_del_rcu(&sdata->list);
773 	synchronize_rcu();
774 	unregister_netdevice(sdata->dev);
775 }
776 
777 /*
778  * Remove all interfaces, may only be called at hardware unregistration
779  * time because it doesn't do RCU-safe list removals.
780  */
781 void ieee80211_remove_interfaces(struct ieee80211_local *local)
782 {
783 	struct ieee80211_sub_if_data *sdata, *tmp;
784 
785 	ASSERT_RTNL();
786 
787 	list_for_each_entry_safe(sdata, tmp, &local->interfaces, list) {
788 		list_del(&sdata->list);
789 		unregister_netdevice(sdata->dev);
790 	}
791 }
792