Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
/*
 * IBSS mode implementation
 * Copyright 2003-2008, Jouni Malinen <j@w1.fi>
 * Copyright 2004, Instant802 Networks, Inc.
 * Copyright 2005, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
 * Copyright 2009, Johannes Berg <johannes@sipsolutions.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/delay.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <net/mac80211.h>
#include <asm/unaligned.h>

#include "ieee80211_i.h"
#include "driver-ops.h"
#include "rate.h"

#define IEEE80211_SCAN_INTERVAL (2 * HZ)
#define IEEE80211_SCAN_INTERVAL_SLOW (15 * HZ)
#define IEEE80211_IBSS_JOIN_TIMEOUT (7 * HZ)

#define IEEE80211_IBSS_MERGE_INTERVAL (30 * HZ)
#define IEEE80211_IBSS_MERGE_DELAY 0x400000
#define IEEE80211_IBSS_INACTIVITY_LIMIT (60 * HZ)

#define IEEE80211_IBSS_MAX_STA_ENTRIES 128


static void ieee80211_rx_mgmt_auth_ibss(struct ieee80211_sub_if_data *sdata,
					struct ieee80211_mgmt *mgmt,
					size_t len)
{
	u16 auth_alg, auth_transaction, status_code;

	if (len < 24 + 6)
		return;

	auth_alg = le16_to_cpu(mgmt->u.auth.auth_alg);
	auth_transaction = le16_to_cpu(mgmt->u.auth.auth_transaction);
	status_code = le16_to_cpu(mgmt->u.auth.status_code);

	/*
	 * IEEE 802.11 standard does not require authentication in IBSS
	 * networks and most implementations do not seem to use it.
	 * However, try to reply to authentication attempts if someone
	 * has actually implemented this.
	 */
	if (auth_alg == WLAN_AUTH_OPEN && auth_transaction == 1)
		ieee80211_send_auth(sdata, 2, WLAN_AUTH_OPEN, NULL, 0,
				    sdata->u.ibss.bssid, NULL, 0, 0);
}

static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
				      const u8 *bssid, const int beacon_int,
				      struct ieee80211_channel *chan,
				      const u32 basic_rates,
				      const u16 capability, u64 tsf)
{
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
	struct ieee80211_local *local = sdata->local;
	int rates, i;
	struct sk_buff *skb;
	struct ieee80211_mgmt *mgmt;
	u8 *pos;
	struct ieee80211_supported_band *sband;
	struct cfg80211_bss *bss;
	u32 bss_change;
	u8 supp_rates[IEEE80211_MAX_SUPP_RATES];

	/* Reset own TSF to allow time synchronization work. */
	drv_reset_tsf(local);

	skb = ifibss->skb;
	rcu_assign_pointer(ifibss->presp, NULL);
	synchronize_rcu();
	skb->data = skb->head;
	skb->len = 0;
	skb_reset_tail_pointer(skb);
	skb_reserve(skb, sdata->local->hw.extra_tx_headroom);

	if (memcmp(ifibss->bssid, bssid, ETH_ALEN))
		sta_info_flush(sdata->local, sdata);

	memcpy(ifibss->bssid, bssid, ETH_ALEN);

	sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;

	local->oper_channel = chan;
	local->oper_channel_type = NL80211_CHAN_NO_HT;
	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);

	sband = local->hw.wiphy->bands[chan->band];

	/* build supported rates array */
	pos = supp_rates;
	for (i = 0; i < sband->n_bitrates; i++) {
		int rate = sband->bitrates[i].bitrate;
		u8 basic = 0;
		if (basic_rates & BIT(i))
			basic = 0x80;
		*pos++ = basic | (u8) (rate / 5);
	}

	/* Build IBSS probe response */
	mgmt = (void *) skb_put(skb, 24 + sizeof(mgmt->u.beacon));
	memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
					  IEEE80211_STYPE_PROBE_RESP);
	memset(mgmt->da, 0xff, ETH_ALEN);
	memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
	memcpy(mgmt->bssid, ifibss->bssid, ETH_ALEN);
	mgmt->u.beacon.beacon_int = cpu_to_le16(beacon_int);
	mgmt->u.beacon.timestamp = cpu_to_le64(tsf);
	mgmt->u.beacon.capab_info = cpu_to_le16(capability);

	pos = skb_put(skb, 2 + ifibss->ssid_len);
	*pos++ = WLAN_EID_SSID;
	*pos++ = ifibss->ssid_len;
	memcpy(pos, ifibss->ssid, ifibss->ssid_len);

	rates = sband->n_bitrates;
	if (rates > 8)
		rates = 8;
	pos = skb_put(skb, 2 + rates);
	*pos++ = WLAN_EID_SUPP_RATES;
	*pos++ = rates;
	memcpy(pos, supp_rates, rates);

	if (sband->band == IEEE80211_BAND_2GHZ) {
		pos = skb_put(skb, 2 + 1);
		*pos++ = WLAN_EID_DS_PARAMS;
		*pos++ = 1;
		*pos++ = ieee80211_frequency_to_channel(chan->center_freq);
	}

	pos = skb_put(skb, 2 + 2);
	*pos++ = WLAN_EID_IBSS_PARAMS;
	*pos++ = 2;
	/* FIX: set ATIM window based on scan results */
	*pos++ = 0;
	*pos++ = 0;

	if (sband->n_bitrates > 8) {
		rates = sband->n_bitrates - 8;
		pos = skb_put(skb, 2 + rates);
		*pos++ = WLAN_EID_EXT_SUPP_RATES;
		*pos++ = rates;
		memcpy(pos, &supp_rates[8], rates);
	}

	if (ifibss->ie_len)
		memcpy(skb_put(skb, ifibss->ie_len),
		       ifibss->ie, ifibss->ie_len);

	rcu_assign_pointer(ifibss->presp, skb);

	sdata->vif.bss_conf.beacon_int = beacon_int;
	bss_change = BSS_CHANGED_BEACON_INT;
	bss_change |= ieee80211_reset_erp_info(sdata);
	bss_change |= BSS_CHANGED_BSSID;
	bss_change |= BSS_CHANGED_BEACON;
	bss_change |= BSS_CHANGED_BEACON_ENABLED;
	ieee80211_bss_info_change_notify(sdata, bss_change);

	ieee80211_sta_def_wmm_params(sdata, sband->n_bitrates, supp_rates);

	ifibss->state = IEEE80211_IBSS_MLME_JOINED;
	mod_timer(&ifibss->timer,
		  round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));

	bss = cfg80211_inform_bss_frame(local->hw.wiphy, local->hw.conf.channel,
					mgmt, skb->len, 0, GFP_KERNEL);
	cfg80211_put_bss(bss);
	cfg80211_ibss_joined(sdata->dev, ifibss->bssid, GFP_KERNEL);
}

static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
				    struct ieee80211_bss *bss)
{
	struct ieee80211_supported_band *sband;
	u32 basic_rates;
	int i, j;
	u16 beacon_int = bss->cbss.beacon_interval;

	if (beacon_int < 10)
		beacon_int = 10;

	sband = sdata->local->hw.wiphy->bands[bss->cbss.channel->band];

	basic_rates = 0;

	for (i = 0; i < bss->supp_rates_len; i++) {
		int rate = (bss->supp_rates[i] & 0x7f) * 5;
		bool is_basic = !!(bss->supp_rates[i] & 0x80);

		for (j = 0; j < sband->n_bitrates; j++) {
			if (sband->bitrates[j].bitrate == rate) {
				if (is_basic)
					basic_rates |= BIT(j);
				break;
			}
		}
	}

	__ieee80211_sta_join_ibss(sdata, bss->cbss.bssid,
				  beacon_int,
				  bss->cbss.channel,
				  basic_rates,
				  bss->cbss.capability,
				  bss->cbss.tsf);
}

static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
				  struct ieee80211_mgmt *mgmt,
				  size_t len,
				  struct ieee80211_rx_status *rx_status,
				  struct ieee802_11_elems *elems,
				  bool beacon)
{
	struct ieee80211_local *local = sdata->local;
	int freq;
	struct ieee80211_bss *bss;
	struct sta_info *sta;
	struct ieee80211_channel *channel;
	u64 beacon_timestamp, rx_timestamp;
	u32 supp_rates = 0;
	enum ieee80211_band band = rx_status->band;

	if (elems->ds_params && elems->ds_params_len == 1)
		freq = ieee80211_channel_to_frequency(elems->ds_params[0]);
	else
		freq = rx_status->freq;

	channel = ieee80211_get_channel(local->hw.wiphy, freq);

	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
		return;

	if (sdata->vif.type == NL80211_IFTYPE_ADHOC && elems->supp_rates &&
	    memcmp(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0) {
		supp_rates = ieee80211_sta_get_rates(local, elems, band);

		rcu_read_lock();

		sta = sta_info_get(local, mgmt->sa);
		if (sta) {
			u32 prev_rates;

			prev_rates = sta->sta.supp_rates[band];
			/* make sure mandatory rates are always added */
			sta->sta.supp_rates[band] = supp_rates |
				ieee80211_mandatory_rates(local, band);

#ifdef CONFIG_MAC80211_IBSS_DEBUG
			if (sta->sta.supp_rates[band] != prev_rates)
				printk(KERN_DEBUG "%s: updated supp_rates set "
				    "for %pM based on beacon info (0x%llx | "
				    "0x%llx -> 0x%llx)\n",
				    sdata->dev->name,
				    sta->sta.addr,
				    (unsigned long long) prev_rates,
				    (unsigned long long) supp_rates,
				    (unsigned long long) sta->sta.supp_rates[band]);
#endif
		} else
			ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, supp_rates);

		rcu_read_unlock();
	}

	bss = ieee80211_bss_info_update(local, rx_status, mgmt, len, elems,
					channel, beacon);
	if (!bss)
		return;

	/* was just updated in ieee80211_bss_info_update */
	beacon_timestamp = bss->cbss.tsf;

	/* check if we need to merge IBSS */

	/* merge only on beacons (???) */
	if (!beacon)
		goto put_bss;

	/* we use a fixed BSSID */
	if (sdata->u.ibss.bssid)
		goto put_bss;

	/* not an IBSS */
	if (!(bss->cbss.capability & WLAN_CAPABILITY_IBSS))
		goto put_bss;

	/* different channel */
	if (bss->cbss.channel != local->oper_channel)
		goto put_bss;

	/* different SSID */
	if (elems->ssid_len != sdata->u.ibss.ssid_len ||
	    memcmp(elems->ssid, sdata->u.ibss.ssid,
				sdata->u.ibss.ssid_len))
		goto put_bss;

	/* same BSSID */
	if (memcmp(bss->cbss.bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0)
		goto put_bss;

	if (rx_status->flag & RX_FLAG_TSFT) {
		/*
		 * For correct IBSS merging we need mactime; since mactime is
		 * defined as the time the first data symbol of the frame hits
		 * the PHY, and the timestamp of the beacon is defined as "the
		 * time that the data symbol containing the first bit of the
		 * timestamp is transmitted to the PHY plus the transmitting
		 * STA's delays through its local PHY from the MAC-PHY
		 * interface to its interface with the WM" (802.11 11.1.2)
		 * - equals the time this bit arrives at the receiver - we have
		 * to take into account the offset between the two.
		 *
		 * E.g. at 1 MBit that means mactime is 192 usec earlier
		 * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
		 */
		int rate;

		if (rx_status->flag & RX_FLAG_HT)
			rate = 65; /* TODO: HT rates */
		else
			rate = local->hw.wiphy->bands[band]->
				bitrates[rx_status->rate_idx].bitrate;

		rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
	} else {
		/*
		 * second best option: get current TSF
		 * (will return -1 if not supported)
		 */
		rx_timestamp = drv_get_tsf(local);
	}

#ifdef CONFIG_MAC80211_IBSS_DEBUG
	printk(KERN_DEBUG "RX beacon SA=%pM BSSID="
	       "%pM TSF=0x%llx BCN=0x%llx diff=%lld @%lu\n",
	       mgmt->sa, mgmt->bssid,
	       (unsigned long long)rx_timestamp,
	       (unsigned long long)beacon_timestamp,
	       (unsigned long long)(rx_timestamp - beacon_timestamp),
	       jiffies);
#endif

	/* give slow hardware some time to do the TSF sync */
	if (rx_timestamp < IEEE80211_IBSS_MERGE_DELAY)
		goto put_bss;

	if (beacon_timestamp > rx_timestamp) {
#ifdef CONFIG_MAC80211_IBSS_DEBUG
		printk(KERN_DEBUG "%s: beacon TSF higher than "
		       "local TSF - IBSS merge with BSSID %pM\n",
		       sdata->dev->name, mgmt->bssid);
#endif
		ieee80211_sta_join_ibss(sdata, bss);
		ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, supp_rates);
	}

 put_bss:
	ieee80211_rx_bss_put(local, bss);
}

/*
 * Add a new IBSS station, will also be called by the RX code when,
 * in IBSS mode, receiving a frame from a yet-unknown station, hence
 * must be callable in atomic context.
 */
struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
					u8 *bssid,u8 *addr, u32 supp_rates)
{
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
	struct ieee80211_local *local = sdata->local;
	struct sta_info *sta;
	int band = local->hw.conf.channel->band;

	/*
	 * XXX: Consider removing the least recently used entry and
	 * 	allow new one to be added.
	 */
	if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
		if (net_ratelimit())
			printk(KERN_DEBUG "%s: No room for a new IBSS STA entry %pM\n",
			       sdata->dev->name, addr);
		return NULL;
	}

	if (ifibss->state == IEEE80211_IBSS_MLME_SEARCH)
		return NULL;

	if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
		return NULL;

#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	printk(KERN_DEBUG "%s: Adding new IBSS station %pM (dev=%s)\n",
	       wiphy_name(local->hw.wiphy), addr, sdata->dev->name);
#endif

	sta = sta_info_alloc(sdata, addr, GFP_ATOMIC);
	if (!sta)
		return NULL;

	set_sta_flags(sta, WLAN_STA_AUTHORIZED);

	/* make sure mandatory rates are always added */
	sta->sta.supp_rates[band] = supp_rates |
			ieee80211_mandatory_rates(local, band);

	rate_control_rate_init(sta);

	if (sta_info_insert(sta))
		return NULL;

	return sta;
}

static int ieee80211_sta_active_ibss(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_local *local = sdata->local;
	int active = 0;
	struct sta_info *sta;

	rcu_read_lock();

	list_for_each_entry_rcu(sta, &local->sta_list, list) {
		if (sta->sdata == sdata &&
		    time_after(sta->last_rx + IEEE80211_IBSS_MERGE_INTERVAL,
			       jiffies)) {
			active++;
			break;
		}
	}

	rcu_read_unlock();

	return active;
}


static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;

	mod_timer(&ifibss->timer,
		  round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));

	ieee80211_sta_expire(sdata, IEEE80211_IBSS_INACTIVITY_LIMIT);

	if (time_before(jiffies, ifibss->last_scan_completed +
		       IEEE80211_IBSS_MERGE_INTERVAL))
		return;

	if (ieee80211_sta_active_ibss(sdata))
		return;

	if (ifibss->fixed_channel)
		return;

	printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
	       "IBSS networks with same SSID (merge)\n", sdata->dev->name);

	ieee80211_request_internal_scan(sdata, ifibss->ssid, ifibss->ssid_len);
}

static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_supported_band *sband;
	u8 bssid[ETH_ALEN];
	u16 capability;
	int i;

	if (ifibss->fixed_bssid) {
		memcpy(bssid, ifibss->bssid, ETH_ALEN);
	} else {
		/* Generate random, not broadcast, locally administered BSSID. Mix in
		 * own MAC address to make sure that devices that do not have proper
		 * random number generator get different BSSID. */
		get_random_bytes(bssid, ETH_ALEN);
		for (i = 0; i < ETH_ALEN; i++)
			bssid[i] ^= sdata->dev->dev_addr[i];
		bssid[0] &= ~0x01;
		bssid[0] |= 0x02;
	}

	printk(KERN_DEBUG "%s: Creating new IBSS network, BSSID %pM\n",
	       sdata->dev->name, bssid);

	sband = local->hw.wiphy->bands[ifibss->channel->band];

	capability = WLAN_CAPABILITY_IBSS;

	if (ifibss->privacy)
		capability |= WLAN_CAPABILITY_PRIVACY;
	else
		sdata->drop_unencrypted = 0;

	__ieee80211_sta_join_ibss(sdata, bssid, sdata->vif.bss_conf.beacon_int,
				  ifibss->channel, 3, /* first two are basic */
				  capability, 0);
}

static void ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_bss *bss;
	struct ieee80211_channel *chan = NULL;
	const u8 *bssid = NULL;
	int active_ibss;
	u16 capability;

	active_ibss = ieee80211_sta_active_ibss(sdata);
#ifdef CONFIG_MAC80211_IBSS_DEBUG
	printk(KERN_DEBUG "%s: sta_find_ibss (active_ibss=%d)\n",
	       sdata->dev->name, active_ibss);
#endif /* CONFIG_MAC80211_IBSS_DEBUG */

	if (active_ibss)
		return;

	capability = WLAN_CAPABILITY_IBSS;
	if (ifibss->privacy)
		capability |= WLAN_CAPABILITY_PRIVACY;
	if (ifibss->fixed_bssid)
		bssid = ifibss->bssid;
	if (ifibss->fixed_channel)
		chan = ifibss->channel;
	if (!is_zero_ether_addr(ifibss->bssid))
		bssid = ifibss->bssid;
	bss = (void *)cfg80211_get_bss(local->hw.wiphy, chan, bssid,
				       ifibss->ssid, ifibss->ssid_len,
				       WLAN_CAPABILITY_IBSS |
				       WLAN_CAPABILITY_PRIVACY,
				       capability);

	if (bss) {
#ifdef CONFIG_MAC80211_IBSS_DEBUG
		printk(KERN_DEBUG "   sta_find_ibss: selected %pM current "
		       "%pM\n", bss->cbss.bssid, ifibss->bssid);
#endif /* CONFIG_MAC80211_IBSS_DEBUG */

		printk(KERN_DEBUG "%s: Selected IBSS BSSID %pM"
		       " based on configured SSID\n",
		       sdata->dev->name, bss->cbss.bssid);

		ieee80211_sta_join_ibss(sdata, bss);
		ieee80211_rx_bss_put(local, bss);
		return;
	}

#ifdef CONFIG_MAC80211_IBSS_DEBUG
	printk(KERN_DEBUG "   did not try to join ibss\n");
#endif /* CONFIG_MAC80211_IBSS_DEBUG */

	/* Selected IBSS not found in current scan results - try to scan */
	if (ifibss->state == IEEE80211_IBSS_MLME_JOINED &&
	    !ieee80211_sta_active_ibss(sdata)) {
		mod_timer(&ifibss->timer,
			  round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
	} else if (time_after(jiffies, ifibss->last_scan_completed +
					IEEE80211_SCAN_INTERVAL)) {
		printk(KERN_DEBUG "%s: Trigger new scan to find an IBSS to "
		       "join\n", sdata->dev->name);

		ieee80211_request_internal_scan(sdata, ifibss->ssid,
						ifibss->ssid_len);
	} else if (ifibss->state != IEEE80211_IBSS_MLME_JOINED) {
		int interval = IEEE80211_SCAN_INTERVAL;

		if (time_after(jiffies, ifibss->ibss_join_req +
			       IEEE80211_IBSS_JOIN_TIMEOUT)) {
			if (!(local->oper_channel->flags & IEEE80211_CHAN_NO_IBSS)) {
				ieee80211_sta_create_ibss(sdata);
				return;
			}
			printk(KERN_DEBUG "%s: IBSS not allowed on"
			       " %d MHz\n", sdata->dev->name,
			       local->hw.conf.channel->center_freq);

			/* No IBSS found - decrease scan interval and continue
			 * scanning. */
			interval = IEEE80211_SCAN_INTERVAL_SLOW;
		}

		ifibss->state = IEEE80211_IBSS_MLME_SEARCH;
		mod_timer(&ifibss->timer,
			  round_jiffies(jiffies + interval));
	}
}

static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
					struct ieee80211_mgmt *mgmt,
					size_t len)
{
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
	struct ieee80211_local *local = sdata->local;
	int tx_last_beacon;
	struct sk_buff *skb;
	struct ieee80211_mgmt *resp;
	u8 *pos, *end;

	if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
	    len < 24 + 2 || !ifibss->presp)
		return;

	tx_last_beacon = drv_tx_last_beacon(local);

#ifdef CONFIG_MAC80211_IBSS_DEBUG
	printk(KERN_DEBUG "%s: RX ProbeReq SA=%pM DA=%pM BSSID=%pM"
	       " (tx_last_beacon=%d)\n",
	       sdata->dev->name, mgmt->sa, mgmt->da,
	       mgmt->bssid, tx_last_beacon);
#endif /* CONFIG_MAC80211_IBSS_DEBUG */

	if (!tx_last_beacon)
		return;

	if (memcmp(mgmt->bssid, ifibss->bssid, ETH_ALEN) != 0 &&
	    memcmp(mgmt->bssid, "\xff\xff\xff\xff\xff\xff", ETH_ALEN) != 0)
		return;

	end = ((u8 *) mgmt) + len;
	pos = mgmt->u.probe_req.variable;
	if (pos[0] != WLAN_EID_SSID ||
	    pos + 2 + pos[1] > end) {
#ifdef CONFIG_MAC80211_IBSS_DEBUG
		printk(KERN_DEBUG "%s: Invalid SSID IE in ProbeReq "
		       "from %pM\n",
		       sdata->dev->name, mgmt->sa);
#endif
		return;
	}
	if (pos[1] != 0 &&
	    (pos[1] != ifibss->ssid_len ||
	     memcmp(pos + 2, ifibss->ssid, ifibss->ssid_len))) {
		/* Ignore ProbeReq for foreign SSID */
		return;
	}

	/* Reply with ProbeResp */
	skb = skb_copy(ifibss->presp, GFP_KERNEL);
	if (!skb)
		return;

	resp = (struct ieee80211_mgmt *) skb->data;
	memcpy(resp->da, mgmt->sa, ETH_ALEN);
#ifdef CONFIG_MAC80211_IBSS_DEBUG
	printk(KERN_DEBUG "%s: Sending ProbeResp to %pM\n",
	       sdata->dev->name, resp->da);
#endif /* CONFIG_MAC80211_IBSS_DEBUG */
	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
	ieee80211_tx_skb(sdata, skb);
}

static void ieee80211_rx_mgmt_probe_resp(struct ieee80211_sub_if_data *sdata,
					 struct ieee80211_mgmt *mgmt,
					 size_t len,
					 struct ieee80211_rx_status *rx_status)
{
	size_t baselen;
	struct ieee802_11_elems elems;

	if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
		return; /* ignore ProbeResp to foreign address */

	baselen = (u8 *) mgmt->u.probe_resp.variable - (u8 *) mgmt;
	if (baselen > len)
		return;

	ieee802_11_parse_elems(mgmt->u.probe_resp.variable, len - baselen,
				&elems);

	ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, false);
}

static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
				     struct ieee80211_mgmt *mgmt,
				     size_t len,
				     struct ieee80211_rx_status *rx_status)
{
	size_t baselen;
	struct ieee802_11_elems elems;

	/* Process beacon from the current BSS */
	baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
	if (baselen > len)
		return;

	ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);

	ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, true);
}

static void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
					  struct sk_buff *skb)
{
	struct ieee80211_rx_status *rx_status;
	struct ieee80211_mgmt *mgmt;
	u16 fc;

	rx_status = IEEE80211_SKB_RXCB(skb);
	mgmt = (struct ieee80211_mgmt *) skb->data;
	fc = le16_to_cpu(mgmt->frame_control);

	switch (fc & IEEE80211_FCTL_STYPE) {
	case IEEE80211_STYPE_PROBE_REQ:
		ieee80211_rx_mgmt_probe_req(sdata, mgmt, skb->len);
		break;
	case IEEE80211_STYPE_PROBE_RESP:
		ieee80211_rx_mgmt_probe_resp(sdata, mgmt, skb->len,
					     rx_status);
		break;
	case IEEE80211_STYPE_BEACON:
		ieee80211_rx_mgmt_beacon(sdata, mgmt, skb->len,
					 rx_status);
		break;
	case IEEE80211_STYPE_AUTH:
		ieee80211_rx_mgmt_auth_ibss(sdata, mgmt, skb->len);
		break;
	}

	kfree_skb(skb);
}

static void ieee80211_ibss_work(struct work_struct *work)
{
	struct ieee80211_sub_if_data *sdata =
		container_of(work, struct ieee80211_sub_if_data, u.ibss.work);
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_if_ibss *ifibss;
	struct sk_buff *skb;

	if (WARN_ON(local->suspended))
		return;

	if (!netif_running(sdata->dev))
		return;

	if (local->scanning)
		return;

	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_ADHOC))
		return;
	ifibss = &sdata->u.ibss;

	while ((skb = skb_dequeue(&ifibss->skb_queue)))
		ieee80211_ibss_rx_queued_mgmt(sdata, skb);

	if (!test_and_clear_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request))
		return;

	switch (ifibss->state) {
	case IEEE80211_IBSS_MLME_SEARCH:
		ieee80211_sta_find_ibss(sdata);
		break;
	case IEEE80211_IBSS_MLME_JOINED:
		ieee80211_sta_merge_ibss(sdata);
		break;
	default:
		WARN_ON(1);
		break;
	}
}

static void ieee80211_ibss_timer(unsigned long data)
{
	struct ieee80211_sub_if_data *sdata =
		(struct ieee80211_sub_if_data *) data;
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
	struct ieee80211_local *local = sdata->local;

	if (local->quiescing) {
		ifibss->timer_running = true;
		return;
	}

	set_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request);
	ieee80211_queue_work(&local->hw, &ifibss->work);
}

#ifdef CONFIG_PM
void ieee80211_ibss_quiesce(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;

	cancel_work_sync(&ifibss->work);
	if (del_timer_sync(&ifibss->timer))
		ifibss->timer_running = true;
}

void ieee80211_ibss_restart(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;

	if (ifibss->timer_running) {
		add_timer(&ifibss->timer);
		ifibss->timer_running = false;
	}
}
#endif

void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;

	INIT_WORK(&ifibss->work, ieee80211_ibss_work);
	setup_timer(&ifibss->timer, ieee80211_ibss_timer,
		    (unsigned long) sdata);
	skb_queue_head_init(&ifibss->skb_queue);
}

/* scan finished notification */
void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local)
{
	struct ieee80211_sub_if_data *sdata;

	mutex_lock(&local->iflist_mtx);
	list_for_each_entry(sdata, &local->interfaces, list) {
		if (!netif_running(sdata->dev))
			continue;
		if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
			continue;
		if (!sdata->u.ibss.ssid_len)
			continue;
		sdata->u.ibss.last_scan_completed = jiffies;
		mod_timer(&sdata->u.ibss.timer, 0);
	}
	mutex_unlock(&local->iflist_mtx);
}

ieee80211_rx_result
ieee80211_ibss_rx_mgmt(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_mgmt *mgmt;
	u16 fc;

	if (skb->len < 24)
		return RX_DROP_MONITOR;

	mgmt = (struct ieee80211_mgmt *) skb->data;
	fc = le16_to_cpu(mgmt->frame_control);

	switch (fc & IEEE80211_FCTL_STYPE) {
	case IEEE80211_STYPE_PROBE_RESP:
	case IEEE80211_STYPE_BEACON:
	case IEEE80211_STYPE_PROBE_REQ:
	case IEEE80211_STYPE_AUTH:
		skb_queue_tail(&sdata->u.ibss.skb_queue, skb);
		ieee80211_queue_work(&local->hw, &sdata->u.ibss.work);
		return RX_QUEUED;
	}

	return RX_DROP_MONITOR;
}

int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
			struct cfg80211_ibss_params *params)
{
	struct sk_buff *skb;

	if (params->bssid) {
		memcpy(sdata->u.ibss.bssid, params->bssid, ETH_ALEN);
		sdata->u.ibss.fixed_bssid = true;
	} else
		sdata->u.ibss.fixed_bssid = false;

	sdata->u.ibss.privacy = params->privacy;

	sdata->vif.bss_conf.beacon_int = params->beacon_interval;

	sdata->u.ibss.channel = params->channel;
	sdata->u.ibss.fixed_channel = params->channel_fixed;

	if (params->ie) {
		sdata->u.ibss.ie = kmemdup(params->ie, params->ie_len,
					   GFP_KERNEL);
		if (sdata->u.ibss.ie)
			sdata->u.ibss.ie_len = params->ie_len;
	}

	skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
			    36 /* bitrates */ +
			    34 /* SSID */ +
			    3  /* DS params */ +
			    4  /* IBSS params */ +
			    params->ie_len);
	if (!skb)
		return -ENOMEM;

	sdata->u.ibss.skb = skb;
	sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
	sdata->u.ibss.ibss_join_req = jiffies;

	memcpy(sdata->u.ibss.ssid, params->ssid, IEEE80211_MAX_SSID_LEN);

	/*
	 * The ssid_len setting below is used to see whether
	 * we are active, and we need all other settings
	 * before that may get visible.
	 */
	mb();

	sdata->u.ibss.ssid_len = params->ssid_len;

	ieee80211_recalc_idle(sdata->local);

	set_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
	ieee80211_queue_work(&sdata->local->hw, &sdata->u.ibss.work);

	return 0;
}

int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
{
	struct sk_buff *skb;

	del_timer_sync(&sdata->u.ibss.timer);
	clear_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
	cancel_work_sync(&sdata->u.ibss.work);
	clear_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);

	sta_info_flush(sdata->local, sdata);

	/* remove beacon */
	kfree(sdata->u.ibss.ie);
	skb = sdata->u.ibss.presp;
	rcu_assign_pointer(sdata->u.ibss.presp, NULL);
	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON_ENABLED);
	synchronize_rcu();
	kfree_skb(skb);

	skb_queue_purge(&sdata->u.ibss.skb_queue);
	memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
	sdata->u.ibss.ssid_len = 0;

	ieee80211_recalc_idle(sdata->local);

	return 0;
}