aboutsummaryrefslogtreecommitdiffstats
path: root/net/mac80211/util.c
blob: cee4884b9d06215f86b73630362fae1f9ab87168 (plain) (blame)
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
/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007	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.
 *
 * utilities for mac80211
 */

#include <net/mac80211.h>
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <linux/wireless.h>
#include <linux/bitmap.h>
#include <net/net_namespace.h>
#include <net/cfg80211.h>
#include <net/rtnetlink.h>

#include "ieee80211_i.h"
#include "rate.h"
#include "mesh.h"
#include "wme.h"

/* privid for wiphys to determine whether they belong to us or not */
void *mac80211_wiphy_privid = &mac80211_wiphy_privid;

/* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
/* Ethernet-II snap header (RFC1042 for most EtherTypes) */
const unsigned char rfc1042_header[] __aligned(2) =
	{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };

/* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
const unsigned char bridge_tunnel_header[] __aligned(2) =
	{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };


u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
			enum nl80211_iftype type)
{
	__le16 fc = hdr->frame_control;

	 /* drop ACK/CTS frames and incorrect hdr len (ctrl) */
	if (len < 16)
		return NULL;

	if (ieee80211_is_data(fc)) {
		if (len < 24) /* drop incorrect hdr len (data) */
			return NULL;

		if (ieee80211_has_a4(fc))
			return NULL;
		if (ieee80211_has_tods(fc))
			return hdr->addr1;
		if (ieee80211_has_fromds(fc))
			return hdr->addr2;

		return hdr->addr3;
	}

	if (ieee80211_is_mgmt(fc)) {
		if (len < 24) /* drop incorrect hdr len (mgmt) */
			return NULL;
		return hdr->addr3;
	}

	if (ieee80211_is_ctl(fc)) {
		if(ieee80211_is_pspoll(fc))
			return hdr->addr1;

		if (ieee80211_is_back_req(fc)) {
			switch (type) {
			case NL80211_IFTYPE_STATION:
				return hdr->addr2;
			case NL80211_IFTYPE_AP:
			case NL80211_IFTYPE_AP_VLAN:
				return hdr->addr1;
			default:
				break; /* fall through to the return */
			}
		}
	}

	return NULL;
}

unsigned int ieee80211_hdrlen(__le16 fc)
{
	unsigned int hdrlen = 24;

	if (ieee80211_is_data(fc)) {
		if (ieee80211_has_a4(fc))
			hdrlen = 30;
		if (ieee80211_is_data_qos(fc))
			hdrlen += IEEE80211_QOS_CTL_LEN;
		goto out;
	}

	if (ieee80211_is_ctl(fc)) {
		/*
		 * ACK and CTS are 10 bytes, all others 16. To see how
		 * to get this condition consider
		 *   subtype mask:   0b0000000011110000 (0x00F0)
		 *   ACK subtype:    0b0000000011010000 (0x00D0)
		 *   CTS subtype:    0b0000000011000000 (0x00C0)
		 *   bits that matter:         ^^^      (0x00E0)
		 *   value of those: 0b0000000011000000 (0x00C0)
		 */
		if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0))
			hdrlen = 10;
		else
			hdrlen = 16;
	}
out:
	return hdrlen;
}
EXPORT_SYMBOL(ieee80211_hdrlen);

unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
{
	const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *)skb->data;
	unsigned int hdrlen;

	if (unlikely(skb->len < 10))
		return 0;
	hdrlen = ieee80211_hdrlen(hdr->frame_control);
	if (unlikely(hdrlen > skb->len))
		return 0;
	return hdrlen;
}
EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);

int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
{
	int ae = meshhdr->flags & IEEE80211S_FLAGS_AE;
	/* 7.1.3.5a.2 */
	switch (ae) {
	case 0:
		return 6;
	case 1:
		return 12;
	case 2:
		return 18;
	case 3:
		return 24;
	default:
		return 6;
	}
}

void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
{
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;

	hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
	if (tx->extra_frag) {
		struct ieee80211_hdr *fhdr;
		int i;
		for (i = 0; i < tx->num_extra_frag; i++) {
			fhdr = (struct ieee80211_hdr *)
				tx->extra_frag[i]->data;
			fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
		}
	}
}

int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
			     int rate, int erp, int short_preamble)
{
	int dur;

	/* calculate duration (in microseconds, rounded up to next higher
	 * integer if it includes a fractional microsecond) to send frame of
	 * len bytes (does not include FCS) at the given rate. Duration will
	 * also include SIFS.
	 *
	 * rate is in 100 kbps, so divident is multiplied by 10 in the
	 * DIV_ROUND_UP() operations.
	 */

	if (local->hw.conf.channel->band == IEEE80211_BAND_5GHZ || erp) {
		/*
		 * OFDM:
		 *
		 * N_DBPS = DATARATE x 4
		 * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
		 *	(16 = SIGNAL time, 6 = tail bits)
		 * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
		 *
		 * T_SYM = 4 usec
		 * 802.11a - 17.5.2: aSIFSTime = 16 usec
		 * 802.11g - 19.8.4: aSIFSTime = 10 usec +
		 *	signal ext = 6 usec
		 */
		dur = 16; /* SIFS + signal ext */
		dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
		dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
		dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
					4 * rate); /* T_SYM x N_SYM */
	} else {
		/*
		 * 802.11b or 802.11g with 802.11b compatibility:
		 * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
		 * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
		 *
		 * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
		 * aSIFSTime = 10 usec
		 * aPreambleLength = 144 usec or 72 usec with short preamble
		 * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
		 */
		dur = 10; /* aSIFSTime = 10 usec */
		dur += short_preamble ? (72 + 24) : (144 + 48);

		dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
	}

	return dur;
}

/* Exported duration function for driver use */
__le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
					struct ieee80211_vif *vif,
					size_t frame_len,
					struct ieee80211_rate *rate)
{
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_sub_if_data *sdata;
	u16 dur;
	int erp;
	bool short_preamble = false;

	erp = 0;
	if (vif) {
		sdata = vif_to_sdata(vif);
		short_preamble = sdata->bss_conf.use_short_preamble;
		if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
			erp = rate->flags & IEEE80211_RATE_ERP_G;
	}

	dur = ieee80211_frame_duration(local, frame_len, rate->bitrate, erp,
				       short_preamble);

	return cpu_to_le16(dur);
}
EXPORT_SYMBOL(ieee80211_generic_frame_duration);

__le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
			      struct ieee80211_vif *vif, size_t frame_len,
			      const struct ieee80211_tx_info *frame_txctl)
{
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_rate *rate;
	struct ieee80211_sub_if_data *sdata;
	bool short_preamble;
	int erp;
	u16 dur;
	struct ieee80211_supported_band *sband;

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

	short_preamble = false;

	rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];

	erp = 0;
	if (vif) {
		sdata = vif_to_sdata(vif);
		short_preamble = sdata->bss_conf.use_short_preamble;
		if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
			erp = rate->flags & IEEE80211_RATE_ERP_G;
	}

	/* CTS duration */
	dur = ieee80211_frame_duration(local, 10, rate->bitrate,
				       erp, short_preamble);
	/* Data frame duration */
	dur += ieee80211_frame_duration(local, frame_len, rate->bitrate,
					erp, short_preamble);
	/* ACK duration */
	dur += ieee80211_frame_duration(local, 10, rate->bitrate,
					erp, short_preamble);

	return cpu_to_le16(dur);
}
EXPORT_SYMBOL(ieee80211_rts_duration);

__le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
				    struct ieee80211_vif *vif,
				    size_t frame_len,
				    const struct ieee80211_tx_info *frame_txctl)
{
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_rate *rate;
	struct ieee80211_sub_if_data *sdata;
	bool short_preamble;
	int erp;
	u16 dur;
	struct ieee80211_supported_band *sband;

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

	short_preamble = false;

	rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
	erp = 0;
	if (vif) {
		sdata = vif_to_sdata(vif);
		short_preamble = sdata->bss_conf.use_short_preamble;
		if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
			erp = rate->flags & IEEE80211_RATE_ERP_G;
	}

	/* Data frame duration */
	dur = ieee80211_frame_duration(local, frame_len, rate->bitrate,
				       erp, short_preamble);
	if (!(frame_txctl->flags & IEEE80211_TX_CTL_NO_ACK)) {
		/* ACK duration */
		dur += ieee80211_frame_duration(local, 10, rate->bitrate,
						erp, short_preamble);
	}

	return cpu_to_le16(dur);
}
EXPORT_SYMBOL(ieee80211_ctstoself_duration);

void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
{
	struct ieee80211_local *local = hw_to_local(hw);

	if (test_bit(queue, local->queues_pending)) {
		set_bit(queue, local->queues_pending_run);
		tasklet_schedule(&local->tx_pending_tasklet);
	} else {
		netif_wake_subqueue(local->mdev, queue);
	}
}
EXPORT_SYMBOL(ieee80211_wake_queue);

void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
{
	struct ieee80211_local *local = hw_to_local(hw);

	netif_stop_subqueue(local->mdev, queue);
}
EXPORT_SYMBOL(ieee80211_stop_queue);

void ieee80211_stop_queues(struct ieee80211_hw *hw)
{
	int i;

	for (i = 0; i < ieee80211_num_queues(hw); i++)
		ieee80211_stop_queue(hw, i);
}
EXPORT_SYMBOL(ieee80211_stop_queues);

int ieee80211_queue_stopped(struct ieee80211_hw *hw, int queue)
{
	struct ieee80211_local *local = hw_to_local(hw);
	return __netif_subqueue_stopped(local->mdev, queue);
}
EXPORT_SYMBOL(ieee80211_queue_stopped);

void ieee80211_wake_queues(struct ieee80211_hw *hw)
{
	int i;

	for (i = 0; i < hw->queues + hw->ampdu_queues; i++)
		ieee80211_wake_queue(hw, i);
}
EXPORT_SYMBOL(ieee80211_wake_queues);

void ieee80211_iterate_active_interfaces(
	struct ieee80211_hw *hw,
	void (*iterator)(void *data, u8 *mac,
			 struct ieee80211_vif *vif),
	void *data)
{
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_sub_if_data *sdata;

	rtnl_lock();

	list_for_each_entry(sdata, &local->interfaces, list) {
		switch (sdata->vif.type) {
		case __NL80211_IFTYPE_AFTER_LAST:
		case NL80211_IFTYPE_UNSPECIFIED:
		case NL80211_IFTYPE_MONITOR:
		case NL80211_IFTYPE_AP_VLAN:
			continue;
		case NL80211_IFTYPE_AP:
		case NL80211_IFTYPE_STATION:
		case NL80211_IFTYPE_ADHOC:
		case NL80211_IFTYPE_WDS:
		case NL80211_IFTYPE_MESH_POINT:
			break;
		}
		if (netif_running(sdata->dev))
			iterator(data, sdata->dev->dev_addr,
				 &sdata->vif);
	}

	rtnl_unlock();
}
EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);

void ieee80211_iterate_active_interfaces_atomic(
	struct ieee80211_hw *hw,
	void (*iterator)(void *data, u8 *mac,
			 struct ieee80211_vif *vif),
	void *data)
{
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_sub_if_data *sdata;

	rcu_read_lock();

	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
		switch (sdata->vif.type) {
		case __NL80211_IFTYPE_AFTER_LAST:
		case NL80211_IFTYPE_UNSPECIFIED:
		case NL80211_IFTYPE_MONITOR:
		case NL80211_IFTYPE_AP_VLAN:
			continue;
		case NL80211_IFTYPE_AP:
		case NL80211_IFTYPE_STATION:
		case NL80211_IFTYPE_ADHOC:
		case NL80211_IFTYPE_WDS:
		case NL80211_IFTYPE_MESH_POINT:
			break;
		}
		if (netif_running(sdata->dev))
			iterator(data, sdata->dev->dev_addr,
				 &sdata->vif);
	}

	rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic);

void ieee802_11_parse_elems(u8 *start, size_t len,
			    struct ieee802_11_elems *elems)
{
	size_t left = len;
	u8 *pos = start;

	memset(elems, 0, sizeof(*elems));
	elems->ie_start = start;
	elems->total_len = len;

	while (left >= 2) {
		u8 id, elen;

		id = *pos++;
		elen = *pos++;
		left -= 2;

		if (elen > left)
			return;

		switch (id) {
		case WLAN_EID_SSID:
			elems->ssid = pos;
			elems->ssid_len = elen;
			break;
		case WLAN_EID_SUPP_RATES:
			elems->supp_rates = pos;
			elems->supp_rates_len = elen;
			break;
		case WLAN_EID_FH_PARAMS:
			elems->fh_params = pos;
			elems->fh_params_len = elen;
			break;
		case WLAN_EID_DS_PARAMS:
			elems->ds_params = pos;
			elems->ds_params_len = elen;
			break;
		case WLAN_EID_CF_PARAMS:
			elems->cf_params = pos;
			elems->cf_params_len = elen;
			break;
		case WLAN_EID_TIM:
			elems->tim = pos;
			elems->tim_len = elen;
			break;
		case WLAN_EID_IBSS_PARAMS:
			elems->ibss_params = pos;
			elems->ibss_params_len = elen;
			break;
		case WLAN_EID_CHALLENGE:
			elems->challenge = pos;
			elems->challenge_len = elen;
			break;
		case WLAN_EID_WPA:
			if (elen >= 4 && pos[0] == 0x00 && pos[1] == 0x50 &&
			    pos[2] == 0xf2) {
				/* Microsoft OUI (00:50:F2) */
				if (pos[3] == 1) {
					/* OUI Type 1 - WPA IE */
					elems->wpa = pos;
					elems->wpa_len = elen;
				} else if (elen >= 5 && pos[3] == 2) {
					if (pos[4] == 0) {
						elems->wmm_info = pos;
						elems->wmm_info_len = elen;
					} else if (pos[4] == 1) {
						elems->wmm_param = pos;
						elems->wmm_param_len = elen;
					}
				}
			}
			break;
		case WLAN_EID_RSN:
			elems->rsn = pos;
			elems->rsn_len = elen;
			break;
		case WLAN_EID_ERP_INFO:
			elems->erp_info = pos;
			elems->erp_info_len = elen;
			break;
		case WLAN_EID_EXT_SUPP_RATES:
			elems->ext_supp_rates = pos;
			elems->ext_supp_rates_len = elen;
			break;
		case WLAN_EID_HT_CAPABILITY:
			if (elen >= sizeof(struct ieee80211_ht_cap))
				elems->ht_cap_elem = (void *)pos;
			break;
		case WLAN_EID_HT_EXTRA_INFO:
			if (elen >= sizeof(struct ieee80211_ht_addt_info))
				elems->ht_info_elem = (void *)pos;
			break;
		case WLAN_EID_MESH_ID:
			elems->mesh_id = pos;
			elems->mesh_id_len = elen;
			break;
		case WLAN_EID_MESH_CONFIG:
			elems->mesh_config = pos;
			elems->mesh_config_len = elen;
			break;
		case WLAN_EID_PEER_LINK:
			elems->peer_link = pos;
			elems->peer_link_len = elen;
			break;
		case WLAN_EID_PREQ:
			elems->preq = pos;
			elems->preq_len = elen;
			break;
		case WLAN_EID_PREP:
			elems->prep = pos;
			elems->prep_len = elen;
			break;
		case WLAN_EID_PERR:
			elems->perr = pos;
			elems->perr_len = elen;
			break;
		case WLAN_EID_CHANNEL_SWITCH:
			elems->ch_switch_elem = pos;
			elems->ch_switch_elem_len = elen;
			break;
		case WLAN_EID_QUIET:
			if (!elems->quiet_elem) {
				elems->quiet_elem = pos;
				elems->quiet_elem_len = elen;
			}
			elems->num_of_quiet_elem++;
			break;
		case WLAN_EID_COUNTRY:
			elems->country_elem = pos;
			elems->country_elem_len = elen;
			break;
		case WLAN_EID_PWR_CONSTRAINT:
			elems->pwr_constr_elem = pos;
			elems->pwr_constr_elem_len = elen;
			break;
		default:
			break;
		}

		left -= elen;
		pos += elen;
	}
}

void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_tx_queue_params qparam;
	int i;

	if (!local->ops->conf_tx)
		return;

	memset(&qparam, 0, sizeof(qparam));

	qparam.aifs = 2;

	if (local->hw.conf.channel->band == IEEE80211_BAND_2GHZ &&
	    !(sdata->flags & IEEE80211_SDATA_OPERATING_GMODE))
		qparam.cw_min = 31;
	else
		qparam.cw_min = 15;

	qparam.cw_max = 1023;
	qparam.txop = 0;

	for (i = 0; i < local_to_hw(local)->queues; i++)
		local->ops->conf_tx(local_to_hw(local), i, &qparam);
}

void ieee80211_tx_skb(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
		      int encrypt)
{
	skb->dev = sdata->local->mdev;
	skb_set_mac_header(skb, 0);
	skb_set_network_header(skb, 0);
	skb_set_transport_header(skb, 0);

	skb->iif = sdata->dev->ifindex;
	skb->do_not_encrypt = !encrypt;

	dev_queue_xmit(skb);
}

int ieee80211_set_freq(struct ieee80211_sub_if_data *sdata, int freqMHz)
{
	int ret = -EINVAL;
	struct ieee80211_channel *chan;
	struct ieee80211_local *local = sdata->local;

	chan = ieee80211_get_channel(local->hw.wiphy, freqMHz);

	if (chan && !(chan->flags & IEEE80211_CHAN_DISABLED)) {
		if (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
		    chan->flags & IEEE80211_CHAN_NO_IBSS) {
			printk(KERN_DEBUG "%s: IBSS not allowed on frequency "
				"%d MHz\n", sdata->dev->name, chan->center_freq);
			return ret;
		}
		local->oper_channel = chan;

		if (local->sw_scanning || local->hw_scanning)
			ret = 0;
		else
			ret = ieee80211_hw_config(local);

		rate_control_clear(local);
	}

	return ret;
}

u64 ieee80211_mandatory_rates(struct ieee80211_local *local,
			      enum ieee80211_band band)
{
	struct ieee80211_supported_band *sband;
	struct ieee80211_rate *bitrates;
	u64 mandatory_rates;
	enum ieee80211_rate_flags mandatory_flag;
	int i;

	sband = local->hw.wiphy->bands[band];
	if (!sband) {
		WARN_ON(1);
		sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
	}

	if (band == IEEE80211_BAND_2GHZ)
		mandatory_flag = IEEE80211_RATE_MANDATORY_B;
	else
		mandatory_flag = IEEE80211_RATE_MANDATORY_A;

	bitrates = sband->bitrates;
	mandatory_rates = 0;
	for (i = 0; i < sband->n_bitrates; i++)
		if (bitrates[i].flags & mandatory_flag)
			mandatory_rates |= BIT(i);
	return mandatory_rates;
}