xref: /linux/net/mac80211/ibss.c (revision ce7240e445303de3ca66e6d08f17a2ec278a5bf6)
1 /*
2  * IBSS mode implementation
3  * Copyright 2003-2008, Jouni Malinen <j@w1.fi>
4  * Copyright 2004, Instant802 Networks, Inc.
5  * Copyright 2005, Devicescape Software, Inc.
6  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
7  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
8  * Copyright 2009, Johannes Berg <johannes@sipsolutions.net>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2 as
12  * published by the Free Software Foundation.
13  */
14 
15 #include <linux/delay.h>
16 #include <linux/slab.h>
17 #include <linux/if_ether.h>
18 #include <linux/skbuff.h>
19 #include <linux/if_arp.h>
20 #include <linux/etherdevice.h>
21 #include <linux/rtnetlink.h>
22 #include <net/mac80211.h>
23 
24 #include "ieee80211_i.h"
25 #include "driver-ops.h"
26 #include "rate.h"
27 
28 #define IEEE80211_SCAN_INTERVAL (2 * HZ)
29 #define IEEE80211_SCAN_INTERVAL_SLOW (15 * HZ)
30 #define IEEE80211_IBSS_JOIN_TIMEOUT (7 * HZ)
31 
32 #define IEEE80211_IBSS_MERGE_INTERVAL (30 * HZ)
33 #define IEEE80211_IBSS_INACTIVITY_LIMIT (60 * HZ)
34 
35 #define IEEE80211_IBSS_MAX_STA_ENTRIES 128
36 
37 
38 static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
39 				      const u8 *bssid, const int beacon_int,
40 				      struct ieee80211_channel *chan,
41 				      const u32 basic_rates,
42 				      const u16 capability, u64 tsf)
43 {
44 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
45 	struct ieee80211_local *local = sdata->local;
46 	int rates, i;
47 	struct sk_buff *skb;
48 	struct ieee80211_mgmt *mgmt;
49 	u8 *pos;
50 	struct ieee80211_supported_band *sband;
51 	struct cfg80211_bss *bss;
52 	u32 bss_change;
53 	u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
54 	enum nl80211_channel_type channel_type;
55 
56 	lockdep_assert_held(&ifibss->mtx);
57 
58 	/* Reset own TSF to allow time synchronization work. */
59 	drv_reset_tsf(local, sdata);
60 
61 	skb = ifibss->skb;
62 	RCU_INIT_POINTER(ifibss->presp, NULL);
63 	synchronize_rcu();
64 	skb->data = skb->head;
65 	skb->len = 0;
66 	skb_reset_tail_pointer(skb);
67 	skb_reserve(skb, sdata->local->hw.extra_tx_headroom);
68 
69 	if (!ether_addr_equal(ifibss->bssid, bssid))
70 		sta_info_flush(sdata->local, sdata);
71 
72 	/* if merging, indicate to driver that we leave the old IBSS */
73 	if (sdata->vif.bss_conf.ibss_joined) {
74 		sdata->vif.bss_conf.ibss_joined = false;
75 		netif_carrier_off(sdata->dev);
76 		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IBSS);
77 	}
78 
79 	memcpy(ifibss->bssid, bssid, ETH_ALEN);
80 
81 	sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;
82 
83 	local->oper_channel = chan;
84 	channel_type = ifibss->channel_type;
85 	if (channel_type > NL80211_CHAN_HT20 &&
86 	    !cfg80211_can_beacon_sec_chan(local->hw.wiphy, chan, channel_type))
87 		channel_type = NL80211_CHAN_HT20;
88 	if (!ieee80211_set_channel_type(local, sdata, channel_type)) {
89 		/* can only fail due to HT40+/- mismatch */
90 		channel_type = NL80211_CHAN_HT20;
91 		WARN_ON(!ieee80211_set_channel_type(local, sdata,
92 						    NL80211_CHAN_HT20));
93 	}
94 	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
95 
96 	sband = local->hw.wiphy->bands[chan->band];
97 
98 	/* build supported rates array */
99 	pos = supp_rates;
100 	for (i = 0; i < sband->n_bitrates; i++) {
101 		int rate = sband->bitrates[i].bitrate;
102 		u8 basic = 0;
103 		if (basic_rates & BIT(i))
104 			basic = 0x80;
105 		*pos++ = basic | (u8) (rate / 5);
106 	}
107 
108 	/* Build IBSS probe response */
109 	mgmt = (void *) skb_put(skb, 24 + sizeof(mgmt->u.beacon));
110 	memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
111 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
112 					  IEEE80211_STYPE_PROBE_RESP);
113 	memset(mgmt->da, 0xff, ETH_ALEN);
114 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
115 	memcpy(mgmt->bssid, ifibss->bssid, ETH_ALEN);
116 	mgmt->u.beacon.beacon_int = cpu_to_le16(beacon_int);
117 	mgmt->u.beacon.timestamp = cpu_to_le64(tsf);
118 	mgmt->u.beacon.capab_info = cpu_to_le16(capability);
119 
120 	pos = skb_put(skb, 2 + ifibss->ssid_len);
121 	*pos++ = WLAN_EID_SSID;
122 	*pos++ = ifibss->ssid_len;
123 	memcpy(pos, ifibss->ssid, ifibss->ssid_len);
124 
125 	rates = sband->n_bitrates;
126 	if (rates > 8)
127 		rates = 8;
128 	pos = skb_put(skb, 2 + rates);
129 	*pos++ = WLAN_EID_SUPP_RATES;
130 	*pos++ = rates;
131 	memcpy(pos, supp_rates, rates);
132 
133 	if (sband->band == IEEE80211_BAND_2GHZ) {
134 		pos = skb_put(skb, 2 + 1);
135 		*pos++ = WLAN_EID_DS_PARAMS;
136 		*pos++ = 1;
137 		*pos++ = ieee80211_frequency_to_channel(chan->center_freq);
138 	}
139 
140 	pos = skb_put(skb, 2 + 2);
141 	*pos++ = WLAN_EID_IBSS_PARAMS;
142 	*pos++ = 2;
143 	/* FIX: set ATIM window based on scan results */
144 	*pos++ = 0;
145 	*pos++ = 0;
146 
147 	if (sband->n_bitrates > 8) {
148 		rates = sband->n_bitrates - 8;
149 		pos = skb_put(skb, 2 + rates);
150 		*pos++ = WLAN_EID_EXT_SUPP_RATES;
151 		*pos++ = rates;
152 		memcpy(pos, &supp_rates[8], rates);
153 	}
154 
155 	if (ifibss->ie_len)
156 		memcpy(skb_put(skb, ifibss->ie_len),
157 		       ifibss->ie, ifibss->ie_len);
158 
159 	/* add HT capability and information IEs */
160 	if (channel_type && sband->ht_cap.ht_supported) {
161 		pos = skb_put(skb, 4 +
162 				   sizeof(struct ieee80211_ht_cap) +
163 				   sizeof(struct ieee80211_ht_operation));
164 		pos = ieee80211_ie_build_ht_cap(pos, &sband->ht_cap,
165 						sband->ht_cap.cap);
166 		/*
167 		 * Note: According to 802.11n-2009 9.13.3.1, HT Protection
168 		 * field and RIFS Mode are reserved in IBSS mode, therefore
169 		 * keep them at 0
170 		 */
171 		pos = ieee80211_ie_build_ht_oper(pos, &sband->ht_cap,
172 						 chan, channel_type, 0);
173 	}
174 
175 	if (local->hw.queues >= IEEE80211_NUM_ACS) {
176 		pos = skb_put(skb, 9);
177 		*pos++ = WLAN_EID_VENDOR_SPECIFIC;
178 		*pos++ = 7; /* len */
179 		*pos++ = 0x00; /* Microsoft OUI 00:50:F2 */
180 		*pos++ = 0x50;
181 		*pos++ = 0xf2;
182 		*pos++ = 2; /* WME */
183 		*pos++ = 0; /* WME info */
184 		*pos++ = 1; /* WME ver */
185 		*pos++ = 0; /* U-APSD no in use */
186 	}
187 
188 	rcu_assign_pointer(ifibss->presp, skb);
189 
190 	sdata->vif.bss_conf.beacon_int = beacon_int;
191 	sdata->vif.bss_conf.basic_rates = basic_rates;
192 	bss_change = BSS_CHANGED_BEACON_INT;
193 	bss_change |= ieee80211_reset_erp_info(sdata);
194 	bss_change |= BSS_CHANGED_BSSID;
195 	bss_change |= BSS_CHANGED_BEACON;
196 	bss_change |= BSS_CHANGED_BEACON_ENABLED;
197 	bss_change |= BSS_CHANGED_BASIC_RATES;
198 	bss_change |= BSS_CHANGED_HT;
199 	bss_change |= BSS_CHANGED_IBSS;
200 	sdata->vif.bss_conf.ibss_joined = true;
201 	ieee80211_bss_info_change_notify(sdata, bss_change);
202 
203 	ieee80211_sta_def_wmm_params(sdata, sband->n_bitrates, supp_rates);
204 
205 	ifibss->state = IEEE80211_IBSS_MLME_JOINED;
206 	mod_timer(&ifibss->timer,
207 		  round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
208 
209 	bss = cfg80211_inform_bss_frame(local->hw.wiphy, local->hw.conf.channel,
210 					mgmt, skb->len, 0, GFP_KERNEL);
211 	cfg80211_put_bss(bss);
212 	netif_carrier_on(sdata->dev);
213 	cfg80211_ibss_joined(sdata->dev, ifibss->bssid, GFP_KERNEL);
214 }
215 
216 static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
217 				    struct ieee80211_bss *bss)
218 {
219 	struct cfg80211_bss *cbss =
220 		container_of((void *)bss, struct cfg80211_bss, priv);
221 	struct ieee80211_supported_band *sband;
222 	u32 basic_rates;
223 	int i, j;
224 	u16 beacon_int = cbss->beacon_interval;
225 
226 	lockdep_assert_held(&sdata->u.ibss.mtx);
227 
228 	if (beacon_int < 10)
229 		beacon_int = 10;
230 
231 	sband = sdata->local->hw.wiphy->bands[cbss->channel->band];
232 
233 	basic_rates = 0;
234 
235 	for (i = 0; i < bss->supp_rates_len; i++) {
236 		int rate = (bss->supp_rates[i] & 0x7f) * 5;
237 		bool is_basic = !!(bss->supp_rates[i] & 0x80);
238 
239 		for (j = 0; j < sband->n_bitrates; j++) {
240 			if (sband->bitrates[j].bitrate == rate) {
241 				if (is_basic)
242 					basic_rates |= BIT(j);
243 				break;
244 			}
245 		}
246 	}
247 
248 	__ieee80211_sta_join_ibss(sdata, cbss->bssid,
249 				  beacon_int,
250 				  cbss->channel,
251 				  basic_rates,
252 				  cbss->capability,
253 				  cbss->tsf);
254 }
255 
256 static struct sta_info *ieee80211_ibss_finish_sta(struct sta_info *sta,
257 						  bool auth)
258 	__acquires(RCU)
259 {
260 	struct ieee80211_sub_if_data *sdata = sta->sdata;
261 	u8 addr[ETH_ALEN];
262 
263 	memcpy(addr, sta->sta.addr, ETH_ALEN);
264 
265 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
266 	wiphy_debug(sdata->local->hw.wiphy,
267 		    "Adding new IBSS station %pM (dev=%s)\n",
268 		    addr, sdata->name);
269 #endif
270 
271 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
272 	sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
273 	/* authorize the station only if the network is not RSN protected. If
274 	 * not wait for the userspace to authorize it */
275 	if (!sta->sdata->u.ibss.control_port)
276 		sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
277 
278 	rate_control_rate_init(sta);
279 
280 	/* If it fails, maybe we raced another insertion? */
281 	if (sta_info_insert_rcu(sta))
282 		return sta_info_get(sdata, addr);
283 	if (auth) {
284 #ifdef CONFIG_MAC80211_IBSS_DEBUG
285 		printk(KERN_DEBUG "TX Auth SA=%pM DA=%pM BSSID=%pM"
286 		       "(auth_transaction=1)\n", sdata->vif.addr,
287 		       sdata->u.ibss.bssid, addr);
288 #endif
289 		ieee80211_send_auth(sdata, 1, WLAN_AUTH_OPEN, NULL, 0,
290 				    addr, sdata->u.ibss.bssid, NULL, 0, 0);
291 	}
292 	return sta;
293 }
294 
295 static struct sta_info *
296 ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
297 		       const u8 *bssid, const u8 *addr,
298 		       u32 supp_rates, bool auth)
299 	__acquires(RCU)
300 {
301 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
302 	struct ieee80211_local *local = sdata->local;
303 	struct sta_info *sta;
304 	int band = local->hw.conf.channel->band;
305 
306 	/*
307 	 * XXX: Consider removing the least recently used entry and
308 	 * 	allow new one to be added.
309 	 */
310 	if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
311 		net_dbg_ratelimited("%s: No room for a new IBSS STA entry %pM\n",
312 				    sdata->name, addr);
313 		rcu_read_lock();
314 		return NULL;
315 	}
316 
317 	if (ifibss->state == IEEE80211_IBSS_MLME_SEARCH) {
318 		rcu_read_lock();
319 		return NULL;
320 	}
321 
322 	if (!ether_addr_equal(bssid, sdata->u.ibss.bssid)) {
323 		rcu_read_lock();
324 		return NULL;
325 	}
326 
327 	sta = sta_info_alloc(sdata, addr, GFP_KERNEL);
328 	if (!sta) {
329 		rcu_read_lock();
330 		return NULL;
331 	}
332 
333 	sta->last_rx = jiffies;
334 
335 	/* make sure mandatory rates are always added */
336 	sta->sta.supp_rates[band] = supp_rates |
337 			ieee80211_mandatory_rates(local, band);
338 
339 	return ieee80211_ibss_finish_sta(sta, auth);
340 }
341 
342 static void ieee80211_rx_mgmt_auth_ibss(struct ieee80211_sub_if_data *sdata,
343 					struct ieee80211_mgmt *mgmt,
344 					size_t len)
345 {
346 	u16 auth_alg, auth_transaction;
347 
348 	lockdep_assert_held(&sdata->u.ibss.mtx);
349 
350 	if (len < 24 + 6)
351 		return;
352 
353 	auth_alg = le16_to_cpu(mgmt->u.auth.auth_alg);
354 	auth_transaction = le16_to_cpu(mgmt->u.auth.auth_transaction);
355 
356 	if (auth_alg != WLAN_AUTH_OPEN || auth_transaction != 1)
357 		return;
358 #ifdef CONFIG_MAC80211_IBSS_DEBUG
359 	printk(KERN_DEBUG "%s: RX Auth SA=%pM DA=%pM BSSID=%pM."
360 	       "(auth_transaction=%d)\n",
361 	       sdata->name, mgmt->sa, mgmt->da, mgmt->bssid, auth_transaction);
362 #endif
363 	sta_info_destroy_addr(sdata, mgmt->sa);
364 	ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, 0, false);
365 	rcu_read_unlock();
366 
367 	/*
368 	 * IEEE 802.11 standard does not require authentication in IBSS
369 	 * networks and most implementations do not seem to use it.
370 	 * However, try to reply to authentication attempts if someone
371 	 * has actually implemented this.
372 	 */
373 	ieee80211_send_auth(sdata, 2, WLAN_AUTH_OPEN, NULL, 0,
374 			    mgmt->sa, sdata->u.ibss.bssid, NULL, 0, 0);
375 }
376 
377 static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
378 				  struct ieee80211_mgmt *mgmt,
379 				  size_t len,
380 				  struct ieee80211_rx_status *rx_status,
381 				  struct ieee802_11_elems *elems,
382 				  bool beacon)
383 {
384 	struct ieee80211_local *local = sdata->local;
385 	int freq;
386 	struct cfg80211_bss *cbss;
387 	struct ieee80211_bss *bss;
388 	struct sta_info *sta;
389 	struct ieee80211_channel *channel;
390 	u64 beacon_timestamp, rx_timestamp;
391 	u32 supp_rates = 0;
392 	enum ieee80211_band band = rx_status->band;
393 	struct ieee80211_supported_band *sband = local->hw.wiphy->bands[band];
394 	bool rates_updated = false;
395 
396 	if (elems->ds_params && elems->ds_params_len == 1)
397 		freq = ieee80211_channel_to_frequency(elems->ds_params[0],
398 						      band);
399 	else
400 		freq = rx_status->freq;
401 
402 	channel = ieee80211_get_channel(local->hw.wiphy, freq);
403 
404 	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
405 		return;
406 
407 	if (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
408 	    ether_addr_equal(mgmt->bssid, sdata->u.ibss.bssid)) {
409 
410 		rcu_read_lock();
411 		sta = sta_info_get(sdata, mgmt->sa);
412 
413 		if (elems->supp_rates) {
414 			supp_rates = ieee80211_sta_get_rates(local, elems,
415 							     band, NULL);
416 			if (sta) {
417 				u32 prev_rates;
418 
419 				prev_rates = sta->sta.supp_rates[band];
420 				/* make sure mandatory rates are always added */
421 				sta->sta.supp_rates[band] = supp_rates |
422 					ieee80211_mandatory_rates(local, band);
423 
424 				if (sta->sta.supp_rates[band] != prev_rates) {
425 #ifdef CONFIG_MAC80211_IBSS_DEBUG
426 					printk(KERN_DEBUG
427 						"%s: updated supp_rates set "
428 						"for %pM based on beacon"
429 						"/probe_resp (0x%x -> 0x%x)\n",
430 						sdata->name, sta->sta.addr,
431 						prev_rates,
432 						sta->sta.supp_rates[band]);
433 #endif
434 					rates_updated = true;
435 				}
436 			} else {
437 				rcu_read_unlock();
438 				sta = ieee80211_ibss_add_sta(sdata, mgmt->bssid,
439 						mgmt->sa, supp_rates, true);
440 			}
441 		}
442 
443 		if (sta && elems->wmm_info)
444 			set_sta_flag(sta, WLAN_STA_WME);
445 
446 		if (sta && elems->ht_operation && elems->ht_cap_elem &&
447 		    sdata->u.ibss.channel_type != NL80211_CHAN_NO_HT) {
448 			/* we both use HT */
449 			struct ieee80211_sta_ht_cap sta_ht_cap_new;
450 			enum nl80211_channel_type channel_type =
451 				ieee80211_ht_oper_to_channel_type(
452 							elems->ht_operation);
453 
454 			ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
455 							  elems->ht_cap_elem,
456 							  &sta_ht_cap_new);
457 
458 			/*
459 			 * fall back to HT20 if we don't use or use
460 			 * the other extension channel
461 			 */
462 			if (!(channel_type == NL80211_CHAN_HT40MINUS ||
463 			      channel_type == NL80211_CHAN_HT40PLUS) ||
464 			    channel_type != sdata->u.ibss.channel_type)
465 				sta_ht_cap_new.cap &=
466 					~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
467 
468 			if (memcmp(&sta->sta.ht_cap, &sta_ht_cap_new,
469 				   sizeof(sta_ht_cap_new))) {
470 				memcpy(&sta->sta.ht_cap, &sta_ht_cap_new,
471 				       sizeof(sta_ht_cap_new));
472 				rates_updated = true;
473 			}
474 		}
475 
476 		if (sta && rates_updated)
477 			rate_control_rate_init(sta);
478 
479 		rcu_read_unlock();
480 	}
481 
482 	bss = ieee80211_bss_info_update(local, rx_status, mgmt, len, elems,
483 					channel, beacon);
484 	if (!bss)
485 		return;
486 
487 	cbss = container_of((void *)bss, struct cfg80211_bss, priv);
488 
489 	/* was just updated in ieee80211_bss_info_update */
490 	beacon_timestamp = cbss->tsf;
491 
492 	/* check if we need to merge IBSS */
493 
494 	/* we use a fixed BSSID */
495 	if (sdata->u.ibss.fixed_bssid)
496 		goto put_bss;
497 
498 	/* not an IBSS */
499 	if (!(cbss->capability & WLAN_CAPABILITY_IBSS))
500 		goto put_bss;
501 
502 	/* different channel */
503 	if (cbss->channel != local->oper_channel)
504 		goto put_bss;
505 
506 	/* different SSID */
507 	if (elems->ssid_len != sdata->u.ibss.ssid_len ||
508 	    memcmp(elems->ssid, sdata->u.ibss.ssid,
509 				sdata->u.ibss.ssid_len))
510 		goto put_bss;
511 
512 	/* same BSSID */
513 	if (ether_addr_equal(cbss->bssid, sdata->u.ibss.bssid))
514 		goto put_bss;
515 
516 	if (rx_status->flag & RX_FLAG_MACTIME_MPDU) {
517 		/*
518 		 * For correct IBSS merging we need mactime; since mactime is
519 		 * defined as the time the first data symbol of the frame hits
520 		 * the PHY, and the timestamp of the beacon is defined as "the
521 		 * time that the data symbol containing the first bit of the
522 		 * timestamp is transmitted to the PHY plus the transmitting
523 		 * STA's delays through its local PHY from the MAC-PHY
524 		 * interface to its interface with the WM" (802.11 11.1.2)
525 		 * - equals the time this bit arrives at the receiver - we have
526 		 * to take into account the offset between the two.
527 		 *
528 		 * E.g. at 1 MBit that means mactime is 192 usec earlier
529 		 * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
530 		 */
531 		int rate;
532 
533 		if (rx_status->flag & RX_FLAG_HT)
534 			rate = 65; /* TODO: HT rates */
535 		else
536 			rate = local->hw.wiphy->bands[band]->
537 				bitrates[rx_status->rate_idx].bitrate;
538 
539 		rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
540 	} else {
541 		/*
542 		 * second best option: get current TSF
543 		 * (will return -1 if not supported)
544 		 */
545 		rx_timestamp = drv_get_tsf(local, sdata);
546 	}
547 
548 #ifdef CONFIG_MAC80211_IBSS_DEBUG
549 	printk(KERN_DEBUG "RX beacon SA=%pM BSSID="
550 	       "%pM TSF=0x%llx BCN=0x%llx diff=%lld @%lu\n",
551 	       mgmt->sa, mgmt->bssid,
552 	       (unsigned long long)rx_timestamp,
553 	       (unsigned long long)beacon_timestamp,
554 	       (unsigned long long)(rx_timestamp - beacon_timestamp),
555 	       jiffies);
556 #endif
557 
558 	if (beacon_timestamp > rx_timestamp) {
559 #ifdef CONFIG_MAC80211_IBSS_DEBUG
560 		printk(KERN_DEBUG "%s: beacon TSF higher than "
561 		       "local TSF - IBSS merge with BSSID %pM\n",
562 		       sdata->name, mgmt->bssid);
563 #endif
564 		ieee80211_sta_join_ibss(sdata, bss);
565 		supp_rates = ieee80211_sta_get_rates(local, elems, band, NULL);
566 		ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa,
567 				       supp_rates, true);
568 		rcu_read_unlock();
569 	}
570 
571  put_bss:
572 	ieee80211_rx_bss_put(local, bss);
573 }
574 
575 void ieee80211_ibss_rx_no_sta(struct ieee80211_sub_if_data *sdata,
576 			      const u8 *bssid, const u8 *addr,
577 			      u32 supp_rates)
578 {
579 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
580 	struct ieee80211_local *local = sdata->local;
581 	struct sta_info *sta;
582 	int band = local->hw.conf.channel->band;
583 
584 	/*
585 	 * XXX: Consider removing the least recently used entry and
586 	 * 	allow new one to be added.
587 	 */
588 	if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
589 		net_dbg_ratelimited("%s: No room for a new IBSS STA entry %pM\n",
590 				    sdata->name, addr);
591 		return;
592 	}
593 
594 	if (ifibss->state == IEEE80211_IBSS_MLME_SEARCH)
595 		return;
596 
597 	if (!ether_addr_equal(bssid, sdata->u.ibss.bssid))
598 		return;
599 
600 	sta = sta_info_alloc(sdata, addr, GFP_ATOMIC);
601 	if (!sta)
602 		return;
603 
604 	sta->last_rx = jiffies;
605 
606 	/* make sure mandatory rates are always added */
607 	sta->sta.supp_rates[band] = supp_rates |
608 			ieee80211_mandatory_rates(local, band);
609 
610 	spin_lock(&ifibss->incomplete_lock);
611 	list_add(&sta->list, &ifibss->incomplete_stations);
612 	spin_unlock(&ifibss->incomplete_lock);
613 	ieee80211_queue_work(&local->hw, &sdata->work);
614 }
615 
616 static int ieee80211_sta_active_ibss(struct ieee80211_sub_if_data *sdata)
617 {
618 	struct ieee80211_local *local = sdata->local;
619 	int active = 0;
620 	struct sta_info *sta;
621 
622 	lockdep_assert_held(&sdata->u.ibss.mtx);
623 
624 	rcu_read_lock();
625 
626 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
627 		if (sta->sdata == sdata &&
628 		    time_after(sta->last_rx + IEEE80211_IBSS_MERGE_INTERVAL,
629 			       jiffies)) {
630 			active++;
631 			break;
632 		}
633 	}
634 
635 	rcu_read_unlock();
636 
637 	return active;
638 }
639 
640 /*
641  * This function is called with state == IEEE80211_IBSS_MLME_JOINED
642  */
643 
644 static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
645 {
646 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
647 
648 	lockdep_assert_held(&ifibss->mtx);
649 
650 	mod_timer(&ifibss->timer,
651 		  round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
652 
653 	ieee80211_sta_expire(sdata, IEEE80211_IBSS_INACTIVITY_LIMIT);
654 
655 	if (time_before(jiffies, ifibss->last_scan_completed +
656 		       IEEE80211_IBSS_MERGE_INTERVAL))
657 		return;
658 
659 	if (ieee80211_sta_active_ibss(sdata))
660 		return;
661 
662 	if (ifibss->fixed_channel)
663 		return;
664 
665 	printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
666 	       "IBSS networks with same SSID (merge)\n", sdata->name);
667 
668 	ieee80211_request_internal_scan(sdata,
669 			ifibss->ssid, ifibss->ssid_len, NULL);
670 }
671 
672 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
673 {
674 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
675 	u8 bssid[ETH_ALEN];
676 	u16 capability;
677 	int i;
678 
679 	lockdep_assert_held(&ifibss->mtx);
680 
681 	if (ifibss->fixed_bssid) {
682 		memcpy(bssid, ifibss->bssid, ETH_ALEN);
683 	} else {
684 		/* Generate random, not broadcast, locally administered BSSID. Mix in
685 		 * own MAC address to make sure that devices that do not have proper
686 		 * random number generator get different BSSID. */
687 		get_random_bytes(bssid, ETH_ALEN);
688 		for (i = 0; i < ETH_ALEN; i++)
689 			bssid[i] ^= sdata->vif.addr[i];
690 		bssid[0] &= ~0x01;
691 		bssid[0] |= 0x02;
692 	}
693 
694 	printk(KERN_DEBUG "%s: Creating new IBSS network, BSSID %pM\n",
695 	       sdata->name, bssid);
696 
697 	capability = WLAN_CAPABILITY_IBSS;
698 
699 	if (ifibss->privacy)
700 		capability |= WLAN_CAPABILITY_PRIVACY;
701 	else
702 		sdata->drop_unencrypted = 0;
703 
704 	__ieee80211_sta_join_ibss(sdata, bssid, sdata->vif.bss_conf.beacon_int,
705 				  ifibss->channel, ifibss->basic_rates,
706 				  capability, 0);
707 }
708 
709 /*
710  * This function is called with state == IEEE80211_IBSS_MLME_SEARCH
711  */
712 
713 static void ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
714 {
715 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
716 	struct ieee80211_local *local = sdata->local;
717 	struct cfg80211_bss *cbss;
718 	struct ieee80211_channel *chan = NULL;
719 	const u8 *bssid = NULL;
720 	int active_ibss;
721 	u16 capability;
722 
723 	lockdep_assert_held(&ifibss->mtx);
724 
725 	active_ibss = ieee80211_sta_active_ibss(sdata);
726 #ifdef CONFIG_MAC80211_IBSS_DEBUG
727 	printk(KERN_DEBUG "%s: sta_find_ibss (active_ibss=%d)\n",
728 	       sdata->name, active_ibss);
729 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
730 
731 	if (active_ibss)
732 		return;
733 
734 	capability = WLAN_CAPABILITY_IBSS;
735 	if (ifibss->privacy)
736 		capability |= WLAN_CAPABILITY_PRIVACY;
737 	if (ifibss->fixed_bssid)
738 		bssid = ifibss->bssid;
739 	if (ifibss->fixed_channel)
740 		chan = ifibss->channel;
741 	if (!is_zero_ether_addr(ifibss->bssid))
742 		bssid = ifibss->bssid;
743 	cbss = cfg80211_get_bss(local->hw.wiphy, chan, bssid,
744 				ifibss->ssid, ifibss->ssid_len,
745 				WLAN_CAPABILITY_IBSS | WLAN_CAPABILITY_PRIVACY,
746 				capability);
747 
748 	if (cbss) {
749 		struct ieee80211_bss *bss;
750 
751 		bss = (void *)cbss->priv;
752 #ifdef CONFIG_MAC80211_IBSS_DEBUG
753 		printk(KERN_DEBUG "   sta_find_ibss: selected %pM current "
754 		       "%pM\n", cbss->bssid, ifibss->bssid);
755 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
756 
757 		printk(KERN_DEBUG "%s: Selected IBSS BSSID %pM"
758 		       " based on configured SSID\n",
759 		       sdata->name, cbss->bssid);
760 
761 		ieee80211_sta_join_ibss(sdata, bss);
762 		ieee80211_rx_bss_put(local, bss);
763 		return;
764 	}
765 
766 #ifdef CONFIG_MAC80211_IBSS_DEBUG
767 	printk(KERN_DEBUG "   did not try to join ibss\n");
768 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
769 
770 	/* Selected IBSS not found in current scan results - try to scan */
771 	if (time_after(jiffies, ifibss->last_scan_completed +
772 					IEEE80211_SCAN_INTERVAL)) {
773 		printk(KERN_DEBUG "%s: Trigger new scan to find an IBSS to "
774 		       "join\n", sdata->name);
775 
776 		ieee80211_request_internal_scan(sdata,
777 				ifibss->ssid, ifibss->ssid_len,
778 				ifibss->fixed_channel ? ifibss->channel : NULL);
779 	} else {
780 		int interval = IEEE80211_SCAN_INTERVAL;
781 
782 		if (time_after(jiffies, ifibss->ibss_join_req +
783 			       IEEE80211_IBSS_JOIN_TIMEOUT)) {
784 			if (!(local->oper_channel->flags & IEEE80211_CHAN_NO_IBSS)) {
785 				ieee80211_sta_create_ibss(sdata);
786 				return;
787 			}
788 			printk(KERN_DEBUG "%s: IBSS not allowed on"
789 			       " %d MHz\n", sdata->name,
790 			       local->hw.conf.channel->center_freq);
791 
792 			/* No IBSS found - decrease scan interval and continue
793 			 * scanning. */
794 			interval = IEEE80211_SCAN_INTERVAL_SLOW;
795 		}
796 
797 		mod_timer(&ifibss->timer,
798 			  round_jiffies(jiffies + interval));
799 	}
800 }
801 
802 static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
803 					struct sk_buff *req)
804 {
805 	struct ieee80211_mgmt *mgmt = (void *)req->data;
806 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
807 	struct ieee80211_local *local = sdata->local;
808 	int tx_last_beacon, len = req->len;
809 	struct sk_buff *skb;
810 	struct ieee80211_mgmt *resp;
811 	struct sk_buff *presp;
812 	u8 *pos, *end;
813 
814 	lockdep_assert_held(&ifibss->mtx);
815 
816 	presp = rcu_dereference_protected(ifibss->presp,
817 					  lockdep_is_held(&ifibss->mtx));
818 
819 	if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
820 	    len < 24 + 2 || !presp)
821 		return;
822 
823 	tx_last_beacon = drv_tx_last_beacon(local);
824 
825 #ifdef CONFIG_MAC80211_IBSS_DEBUG
826 	printk(KERN_DEBUG "%s: RX ProbeReq SA=%pM DA=%pM BSSID=%pM"
827 	       " (tx_last_beacon=%d)\n",
828 	       sdata->name, mgmt->sa, mgmt->da,
829 	       mgmt->bssid, tx_last_beacon);
830 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
831 
832 	if (!tx_last_beacon && is_multicast_ether_addr(mgmt->da))
833 		return;
834 
835 	if (!ether_addr_equal(mgmt->bssid, ifibss->bssid) &&
836 	    !is_broadcast_ether_addr(mgmt->bssid))
837 		return;
838 
839 	end = ((u8 *) mgmt) + len;
840 	pos = mgmt->u.probe_req.variable;
841 	if (pos[0] != WLAN_EID_SSID ||
842 	    pos + 2 + pos[1] > end) {
843 #ifdef CONFIG_MAC80211_IBSS_DEBUG
844 		printk(KERN_DEBUG "%s: Invalid SSID IE in ProbeReq "
845 		       "from %pM\n",
846 		       sdata->name, mgmt->sa);
847 #endif
848 		return;
849 	}
850 	if (pos[1] != 0 &&
851 	    (pos[1] != ifibss->ssid_len ||
852 	     memcmp(pos + 2, ifibss->ssid, ifibss->ssid_len))) {
853 		/* Ignore ProbeReq for foreign SSID */
854 		return;
855 	}
856 
857 	/* Reply with ProbeResp */
858 	skb = skb_copy(presp, GFP_KERNEL);
859 	if (!skb)
860 		return;
861 
862 	resp = (struct ieee80211_mgmt *) skb->data;
863 	memcpy(resp->da, mgmt->sa, ETH_ALEN);
864 #ifdef CONFIG_MAC80211_IBSS_DEBUG
865 	printk(KERN_DEBUG "%s: Sending ProbeResp to %pM\n",
866 	       sdata->name, resp->da);
867 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
868 	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
869 	ieee80211_tx_skb(sdata, skb);
870 }
871 
872 static void ieee80211_rx_mgmt_probe_resp(struct ieee80211_sub_if_data *sdata,
873 					 struct ieee80211_mgmt *mgmt,
874 					 size_t len,
875 					 struct ieee80211_rx_status *rx_status)
876 {
877 	size_t baselen;
878 	struct ieee802_11_elems elems;
879 
880 	baselen = (u8 *) mgmt->u.probe_resp.variable - (u8 *) mgmt;
881 	if (baselen > len)
882 		return;
883 
884 	ieee802_11_parse_elems(mgmt->u.probe_resp.variable, len - baselen,
885 				&elems);
886 
887 	ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, false);
888 }
889 
890 static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
891 				     struct ieee80211_mgmt *mgmt,
892 				     size_t len,
893 				     struct ieee80211_rx_status *rx_status)
894 {
895 	size_t baselen;
896 	struct ieee802_11_elems elems;
897 
898 	/* Process beacon from the current BSS */
899 	baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
900 	if (baselen > len)
901 		return;
902 
903 	ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);
904 
905 	ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, true);
906 }
907 
908 void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
909 				   struct sk_buff *skb)
910 {
911 	struct ieee80211_rx_status *rx_status;
912 	struct ieee80211_mgmt *mgmt;
913 	u16 fc;
914 
915 	rx_status = IEEE80211_SKB_RXCB(skb);
916 	mgmt = (struct ieee80211_mgmt *) skb->data;
917 	fc = le16_to_cpu(mgmt->frame_control);
918 
919 	mutex_lock(&sdata->u.ibss.mtx);
920 
921 	if (!sdata->u.ibss.ssid_len)
922 		goto mgmt_out; /* not ready to merge yet */
923 
924 	switch (fc & IEEE80211_FCTL_STYPE) {
925 	case IEEE80211_STYPE_PROBE_REQ:
926 		ieee80211_rx_mgmt_probe_req(sdata, skb);
927 		break;
928 	case IEEE80211_STYPE_PROBE_RESP:
929 		ieee80211_rx_mgmt_probe_resp(sdata, mgmt, skb->len,
930 					     rx_status);
931 		break;
932 	case IEEE80211_STYPE_BEACON:
933 		ieee80211_rx_mgmt_beacon(sdata, mgmt, skb->len,
934 					 rx_status);
935 		break;
936 	case IEEE80211_STYPE_AUTH:
937 		ieee80211_rx_mgmt_auth_ibss(sdata, mgmt, skb->len);
938 		break;
939 	}
940 
941  mgmt_out:
942 	mutex_unlock(&sdata->u.ibss.mtx);
943 }
944 
945 void ieee80211_ibss_work(struct ieee80211_sub_if_data *sdata)
946 {
947 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
948 	struct sta_info *sta;
949 
950 	mutex_lock(&ifibss->mtx);
951 
952 	/*
953 	 * Work could be scheduled after scan or similar
954 	 * when we aren't even joined (or trying) with a
955 	 * network.
956 	 */
957 	if (!ifibss->ssid_len)
958 		goto out;
959 
960 	spin_lock_bh(&ifibss->incomplete_lock);
961 	while (!list_empty(&ifibss->incomplete_stations)) {
962 		sta = list_first_entry(&ifibss->incomplete_stations,
963 				       struct sta_info, list);
964 		list_del(&sta->list);
965 		spin_unlock_bh(&ifibss->incomplete_lock);
966 
967 		ieee80211_ibss_finish_sta(sta, true);
968 		rcu_read_unlock();
969 		spin_lock_bh(&ifibss->incomplete_lock);
970 	}
971 	spin_unlock_bh(&ifibss->incomplete_lock);
972 
973 	switch (ifibss->state) {
974 	case IEEE80211_IBSS_MLME_SEARCH:
975 		ieee80211_sta_find_ibss(sdata);
976 		break;
977 	case IEEE80211_IBSS_MLME_JOINED:
978 		ieee80211_sta_merge_ibss(sdata);
979 		break;
980 	default:
981 		WARN_ON(1);
982 		break;
983 	}
984 
985  out:
986 	mutex_unlock(&ifibss->mtx);
987 }
988 
989 static void ieee80211_ibss_timer(unsigned long data)
990 {
991 	struct ieee80211_sub_if_data *sdata =
992 		(struct ieee80211_sub_if_data *) data;
993 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
994 	struct ieee80211_local *local = sdata->local;
995 
996 	if (local->quiescing) {
997 		ifibss->timer_running = true;
998 		return;
999 	}
1000 
1001 	ieee80211_queue_work(&local->hw, &sdata->work);
1002 }
1003 
1004 #ifdef CONFIG_PM
1005 void ieee80211_ibss_quiesce(struct ieee80211_sub_if_data *sdata)
1006 {
1007 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
1008 
1009 	if (del_timer_sync(&ifibss->timer))
1010 		ifibss->timer_running = true;
1011 }
1012 
1013 void ieee80211_ibss_restart(struct ieee80211_sub_if_data *sdata)
1014 {
1015 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
1016 
1017 	if (ifibss->timer_running) {
1018 		add_timer(&ifibss->timer);
1019 		ifibss->timer_running = false;
1020 	}
1021 }
1022 #endif
1023 
1024 void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata)
1025 {
1026 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
1027 
1028 	setup_timer(&ifibss->timer, ieee80211_ibss_timer,
1029 		    (unsigned long) sdata);
1030 	mutex_init(&ifibss->mtx);
1031 	INIT_LIST_HEAD(&ifibss->incomplete_stations);
1032 	spin_lock_init(&ifibss->incomplete_lock);
1033 }
1034 
1035 /* scan finished notification */
1036 void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local)
1037 {
1038 	struct ieee80211_sub_if_data *sdata;
1039 
1040 	mutex_lock(&local->iflist_mtx);
1041 	list_for_each_entry(sdata, &local->interfaces, list) {
1042 		if (!ieee80211_sdata_running(sdata))
1043 			continue;
1044 		if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
1045 			continue;
1046 		sdata->u.ibss.last_scan_completed = jiffies;
1047 		ieee80211_queue_work(&local->hw, &sdata->work);
1048 	}
1049 	mutex_unlock(&local->iflist_mtx);
1050 }
1051 
1052 int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
1053 			struct cfg80211_ibss_params *params)
1054 {
1055 	struct sk_buff *skb;
1056 	u32 changed = 0;
1057 
1058 	skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
1059 			    sizeof(struct ieee80211_hdr_3addr) +
1060 			    12 /* struct ieee80211_mgmt.u.beacon */ +
1061 			    2 + IEEE80211_MAX_SSID_LEN /* max SSID */ +
1062 			    2 + 8 /* max Supported Rates */ +
1063 			    3 /* max DS params */ +
1064 			    4 /* IBSS params */ +
1065 			    2 + (IEEE80211_MAX_SUPP_RATES - 8) +
1066 			    2 + sizeof(struct ieee80211_ht_cap) +
1067 			    2 + sizeof(struct ieee80211_ht_operation) +
1068 			    params->ie_len);
1069 	if (!skb)
1070 		return -ENOMEM;
1071 
1072 	mutex_lock(&sdata->u.ibss.mtx);
1073 
1074 	if (params->bssid) {
1075 		memcpy(sdata->u.ibss.bssid, params->bssid, ETH_ALEN);
1076 		sdata->u.ibss.fixed_bssid = true;
1077 	} else
1078 		sdata->u.ibss.fixed_bssid = false;
1079 
1080 	sdata->u.ibss.privacy = params->privacy;
1081 	sdata->u.ibss.control_port = params->control_port;
1082 	sdata->u.ibss.basic_rates = params->basic_rates;
1083 	memcpy(sdata->vif.bss_conf.mcast_rate, params->mcast_rate,
1084 	       sizeof(params->mcast_rate));
1085 
1086 	sdata->vif.bss_conf.beacon_int = params->beacon_interval;
1087 
1088 	sdata->u.ibss.channel = params->channel;
1089 	sdata->u.ibss.channel_type = params->channel_type;
1090 	sdata->u.ibss.fixed_channel = params->channel_fixed;
1091 
1092 	/* fix ourselves to that channel now already */
1093 	if (params->channel_fixed) {
1094 		sdata->local->oper_channel = params->channel;
1095 		if (!ieee80211_set_channel_type(sdata->local, sdata,
1096 					       params->channel_type)) {
1097 			mutex_unlock(&sdata->u.ibss.mtx);
1098 			kfree_skb(skb);
1099 			return -EINVAL;
1100 		}
1101 	}
1102 
1103 	if (params->ie) {
1104 		sdata->u.ibss.ie = kmemdup(params->ie, params->ie_len,
1105 					   GFP_KERNEL);
1106 		if (sdata->u.ibss.ie)
1107 			sdata->u.ibss.ie_len = params->ie_len;
1108 	}
1109 
1110 	sdata->u.ibss.skb = skb;
1111 	sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
1112 	sdata->u.ibss.ibss_join_req = jiffies;
1113 
1114 	memcpy(sdata->u.ibss.ssid, params->ssid, IEEE80211_MAX_SSID_LEN);
1115 	sdata->u.ibss.ssid_len = params->ssid_len;
1116 
1117 	mutex_unlock(&sdata->u.ibss.mtx);
1118 
1119 	mutex_lock(&sdata->local->mtx);
1120 	ieee80211_recalc_idle(sdata->local);
1121 	mutex_unlock(&sdata->local->mtx);
1122 
1123 	/*
1124 	 * 802.11n-2009 9.13.3.1: In an IBSS, the HT Protection field is
1125 	 * reserved, but an HT STA shall protect HT transmissions as though
1126 	 * the HT Protection field were set to non-HT mixed mode.
1127 	 *
1128 	 * In an IBSS, the RIFS Mode field of the HT Operation element is
1129 	 * also reserved, but an HT STA shall operate as though this field
1130 	 * were set to 1.
1131 	 */
1132 
1133 	sdata->vif.bss_conf.ht_operation_mode |=
1134 		  IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED
1135 		| IEEE80211_HT_PARAM_RIFS_MODE;
1136 
1137 	changed |= BSS_CHANGED_HT;
1138 	ieee80211_bss_info_change_notify(sdata, changed);
1139 
1140 	ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1141 
1142 	return 0;
1143 }
1144 
1145 int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
1146 {
1147 	struct sk_buff *skb;
1148 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
1149 	struct ieee80211_local *local = sdata->local;
1150 	struct cfg80211_bss *cbss;
1151 	u16 capability;
1152 	int active_ibss;
1153 	struct sta_info *sta;
1154 
1155 	mutex_lock(&sdata->u.ibss.mtx);
1156 
1157 	sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
1158 	memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
1159 	sdata->u.ibss.ssid_len = 0;
1160 
1161 	active_ibss = ieee80211_sta_active_ibss(sdata);
1162 
1163 	if (!active_ibss && !is_zero_ether_addr(ifibss->bssid)) {
1164 		capability = WLAN_CAPABILITY_IBSS;
1165 
1166 		if (ifibss->privacy)
1167 			capability |= WLAN_CAPABILITY_PRIVACY;
1168 
1169 		cbss = cfg80211_get_bss(local->hw.wiphy, ifibss->channel,
1170 					ifibss->bssid, ifibss->ssid,
1171 					ifibss->ssid_len, WLAN_CAPABILITY_IBSS |
1172 					WLAN_CAPABILITY_PRIVACY,
1173 					capability);
1174 
1175 		if (cbss) {
1176 			cfg80211_unlink_bss(local->hw.wiphy, cbss);
1177 			cfg80211_put_bss(cbss);
1178 		}
1179 	}
1180 
1181 	sta_info_flush(sdata->local, sdata);
1182 
1183 	spin_lock_bh(&ifibss->incomplete_lock);
1184 	while (!list_empty(&ifibss->incomplete_stations)) {
1185 		sta = list_first_entry(&ifibss->incomplete_stations,
1186 				       struct sta_info, list);
1187 		list_del(&sta->list);
1188 		spin_unlock_bh(&ifibss->incomplete_lock);
1189 
1190 		sta_info_free(local, sta);
1191 		spin_lock_bh(&ifibss->incomplete_lock);
1192 	}
1193 	spin_unlock_bh(&ifibss->incomplete_lock);
1194 
1195 	netif_carrier_off(sdata->dev);
1196 
1197 	/* remove beacon */
1198 	kfree(sdata->u.ibss.ie);
1199 	skb = rcu_dereference_protected(sdata->u.ibss.presp,
1200 					lockdep_is_held(&sdata->u.ibss.mtx));
1201 	RCU_INIT_POINTER(sdata->u.ibss.presp, NULL);
1202 	sdata->vif.bss_conf.ibss_joined = false;
1203 	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON_ENABLED |
1204 						BSS_CHANGED_IBSS);
1205 	synchronize_rcu();
1206 	kfree_skb(skb);
1207 
1208 	skb_queue_purge(&sdata->skb_queue);
1209 
1210 	del_timer_sync(&sdata->u.ibss.timer);
1211 
1212 	mutex_unlock(&sdata->u.ibss.mtx);
1213 
1214 	mutex_lock(&local->mtx);
1215 	ieee80211_recalc_idle(sdata->local);
1216 	mutex_unlock(&local->mtx);
1217 
1218 	return 0;
1219 }
1220