aboutsummaryrefslogtreecommitdiffstats
path: root/net/wireless/chan.c
blob: 50f6195c8b70b816ab35ade4075c5f71de105b35 (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
/*
 * This file contains helper code to handle channel
 * settings and keeping track of what is possible at
 * any point in time.
 *
 * Copyright 2009	Johannes Berg <johannes@sipsolutions.net>
 */

#include <linux/export.h>
#include <net/cfg80211.h>
#include "core.h"
#include "rdev-ops.h"

void cfg80211_chandef_create(struct cfg80211_chan_def *chandef,
			     struct ieee80211_channel *chan,
			     enum nl80211_channel_type chan_type)
{
	if (WARN_ON(!chan))
		return;

	chandef->chan = chan;
	chandef->center_freq2 = 0;

	switch (chan_type) {
	case NL80211_CHAN_NO_HT:
		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
		chandef->center_freq1 = chan->center_freq;
		break;
	case NL80211_CHAN_HT20:
		chandef->width = NL80211_CHAN_WIDTH_20;
		chandef->center_freq1 = chan->center_freq;
		break;
	case NL80211_CHAN_HT40PLUS:
		chandef->width = NL80211_CHAN_WIDTH_40;
		chandef->center_freq1 = chan->center_freq + 10;
		break;
	case NL80211_CHAN_HT40MINUS:
		chandef->width = NL80211_CHAN_WIDTH_40;
		chandef->center_freq1 = chan->center_freq - 10;
		break;
	default:
		WARN_ON(1);
	}
}
EXPORT_SYMBOL(cfg80211_chandef_create);

bool cfg80211_chandef_valid(const struct cfg80211_chan_def *chandef)
{
	u32 control_freq;

	if (!chandef->chan)
		return false;

	control_freq = chandef->chan->center_freq;

	switch (chandef->width) {
	case NL80211_CHAN_WIDTH_5:
	case NL80211_CHAN_WIDTH_10:
	case NL80211_CHAN_WIDTH_20:
	case NL80211_CHAN_WIDTH_20_NOHT:
		if (chandef->center_freq1 != control_freq)
			return false;
		if (chandef->center_freq2)
			return false;
		break;
	case NL80211_CHAN_WIDTH_40:
		if (chandef->center_freq1 != control_freq + 10 &&
		    chandef->center_freq1 != control_freq - 10)
			return false;
		if (chandef->center_freq2)
			return false;
		break;
	case NL80211_CHAN_WIDTH_80P80:
		if (chandef->center_freq1 != control_freq + 30 &&
		    chandef->center_freq1 != control_freq + 10 &&
		    chandef->center_freq1 != control_freq - 10 &&
		    chandef->center_freq1 != control_freq - 30)
			return false;
		if (!chandef->center_freq2)
			return false;
		/* adjacent is not allowed -- that's a 160 MHz channel */
		if (chandef->center_freq1 - chandef->center_freq2 == 80 ||
		    chandef->center_freq2 - chandef->center_freq1 == 80)
			return false;
		break;
	case NL80211_CHAN_WIDTH_80:
		if (chandef->center_freq1 != control_freq + 30 &&
		    chandef->center_freq1 != control_freq + 10 &&
		    chandef->center_freq1 != control_freq - 10 &&
		    chandef->center_freq1 != control_freq - 30)
			return false;
		if (chandef->center_freq2)
			return false;
		break;
	case NL80211_CHAN_WIDTH_160:
		if (chandef->center_freq1 != control_freq + 70 &&
		    chandef->center_freq1 != control_freq + 50 &&
		    chandef->center_freq1 != control_freq + 30 &&
		    chandef->center_freq1 != control_freq + 10 &&
		    chandef->center_freq1 != control_freq - 10 &&
		    chandef->center_freq1 != control_freq - 30 &&
		    chandef->center_freq1 != control_freq - 50 &&
		    chandef->center_freq1 != control_freq - 70)
			return false;
		if (chandef->center_freq2)
			return false;
		break;
	default:
		return false;
	}

	return true;
}
EXPORT_SYMBOL(cfg80211_chandef_valid);

static void chandef_primary_freqs(const struct cfg80211_chan_def *c,
				  int *pri40, int *pri80)
{
	int tmp;

	switch (c->width) {
	case NL80211_CHAN_WIDTH_40:
		*pri40 = c->center_freq1;
		*pri80 = 0;
		break;
	case NL80211_CHAN_WIDTH_80:
	case NL80211_CHAN_WIDTH_80P80:
		*pri80 = c->center_freq1;
		/* n_P20 */
		tmp = (30 + c->chan->center_freq - c->center_freq1)/20;
		/* n_P40 */
		tmp /= 2;
		/* freq_P40 */
		*pri40 = c->center_freq1 - 20 + 40 * tmp;
		break;
	case NL80211_CHAN_WIDTH_160:
		/* n_P20 */
		tmp = (70 + c->chan->center_freq - c->center_freq1)/20;
		/* n_P40 */
		tmp /= 2;
		/* freq_P40 */
		*pri40 = c->center_freq1 - 60 + 40 * tmp;
		/* n_P80 */
		tmp /= 2;
		*pri80 = c->center_freq1 - 40 + 80 * tmp;
		break;
	default:
		WARN_ON_ONCE(1);
	}
}

static int cfg80211_chandef_get_width(const struct cfg80211_chan_def *c)
{
	int width;

	switch (c->width) {
	case NL80211_CHAN_WIDTH_5:
		width = 5;
		break;
	case NL80211_CHAN_WIDTH_10:
		width = 10;
		break;
	case NL80211_CHAN_WIDTH_20:
	case NL80211_CHAN_WIDTH_20_NOHT:
		width = 20;
		break;
	case NL80211_CHAN_WIDTH_40:
		width = 40;
		break;
	case NL80211_CHAN_WIDTH_80P80:
	case NL80211_CHAN_WIDTH_80:
		width = 80;
		break;
	case NL80211_CHAN_WIDTH_160:
		width = 160;
		break;
	default:
		WARN_ON_ONCE(1);
		return -1;
	}
	return width;
}

const struct cfg80211_chan_def *
cfg80211_chandef_compatible(const struct cfg80211_chan_def *c1,
			    const struct cfg80211_chan_def *c2)
{
	u32 c1_pri40, c1_pri80, c2_pri40, c2_pri80;

	/* If they are identical, return */
	if (cfg80211_chandef_identical(c1, c2))
		return c1;

	/* otherwise, must have same control channel */
	if (c1->chan != c2->chan)
		return NULL;

	/*
	 * If they have the same width, but aren't identical,
	 * then they can't be compatible.
	 */
	if (c1->width == c2->width)
		return NULL;

	/*
	 * can't be compatible if one of them is 5 or 10 MHz,
	 * but they don't have the same width.
	 */
	if (c1->width == NL80211_CHAN_WIDTH_5 ||
	    c1->width == NL80211_CHAN_WIDTH_10 ||
	    c2->width == NL80211_CHAN_WIDTH_5 ||
	    c2->width == NL80211_CHAN_WIDTH_10)
		return NULL;

	if (c1->width == NL80211_CHAN_WIDTH_20_NOHT ||
	    c1->width == NL80211_CHAN_WIDTH_20)
		return c2;

	if (c2->width == NL80211_CHAN_WIDTH_20_NOHT ||
	    c2->width == NL80211_CHAN_WIDTH_20)
		return c1;

	chandef_primary_freqs(c1, &c1_pri40, &c1_pri80);
	chandef_primary_freqs(c2, &c2_pri40, &c2_pri80);

	if (c1_pri40 != c2_pri40)
		return NULL;

	WARN_ON(!c1_pri80 && !c2_pri80);
	if (c1_pri80 && c2_pri80 && c1_pri80 != c2_pri80)
		return NULL;

	if (c1->width > c2->width)
		return c1;
	return c2;
}
EXPORT_SYMBOL(cfg80211_chandef_compatible);

static void cfg80211_set_chans_dfs_state(struct wiphy *wiphy, u32 center_freq,
					 u32 bandwidth,
					 enum nl80211_dfs_state dfs_state)
{
	struct ieee80211_channel *c;
	u32 freq;

	for (freq = center_freq - bandwidth/2 + 10;
	     freq <= center_freq + bandwidth/2 - 10;
	     freq += 20) {
		c = ieee80211_get_channel(wiphy, freq);
		if (!c || !(c->flags & IEEE80211_CHAN_RADAR))
			continue;

		c->dfs_state = dfs_state;
		c->dfs_state_entered = jiffies;
	}
}

void cfg80211_set_dfs_state(struct wiphy *wiphy,
			    const struct cfg80211_chan_def *chandef,
			    enum nl80211_dfs_state dfs_state)
{
	int width;

	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
		return;

	width = cfg80211_chandef_get_width(chandef);
	if (width < 0)
		return;

	cfg80211_set_chans_dfs_state(wiphy, chandef->center_freq1,
				     width, dfs_state);

	if (!chandef->center_freq2)
		return;
	cfg80211_set_chans_dfs_state(wiphy, chandef->center_freq2,
				     width, dfs_state);
}

static int cfg80211_get_chans_dfs_required(struct wiphy *wiphy,
					    u32 center_freq,
					    u32 bandwidth)
{
	struct ieee80211_channel *c;
	u32 freq, start_freq, end_freq;

	if (bandwidth <= 20) {
		start_freq = center_freq;
		end_freq = center_freq;
	} else {
		start_freq = center_freq - bandwidth/2 + 10;
		end_freq = center_freq + bandwidth/2 - 10;
	}

	for (freq = start_freq; freq <= end_freq; freq += 20) {
		c = ieee80211_get_channel(wiphy, freq);
		if (!c)
			return -EINVAL;

		if (c->flags & IEEE80211_CHAN_RADAR)
			return 1;
	}
	return 0;
}


int cfg80211_chandef_dfs_required(struct wiphy *wiphy,
				  const struct cfg80211_chan_def *chandef)
{
	int width;
	int r;

	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
		return -EINVAL;

	width = cfg80211_chandef_get_width(chandef);
	if (width < 0)
		return -EINVAL;

	r = cfg80211_get_chans_dfs_required(wiphy, chandef->center_freq1,
					    width);
	if (r)
		return r;

	if (!chandef->center_freq2)
		return 0;

	return cfg80211_get_chans_dfs_required(wiphy, chandef->center_freq2,
					       width);
}

static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
					u32 center_freq, u32 bandwidth,
					u32 prohibited_flags)
{
	struct ieee80211_channel *c;
	u32 freq, start_freq, end_freq;

	if (bandwidth <= 20) {
		start_freq = center_freq;
		end_freq = center_freq;
	} else {
		start_freq = center_freq - bandwidth/2 + 10;
		end_freq = center_freq + bandwidth/2 - 10;
	}

	for (freq = start_freq; freq <= end_freq; freq += 20) {
		c = ieee80211_get_channel(wiphy, freq);
		if (!c)
			return false;

		/* check for radar flags */
		if ((prohibited_flags & c->flags & IEEE80211_CHAN_RADAR) &&
		    (c->dfs_state != NL80211_DFS_AVAILABLE))
			return false;

		/* check for the other flags */
		if (c->flags & prohibited_flags & ~IEEE80211_CHAN_RADAR)
			return false;
	}

	return true;
}

bool cfg80211_chandef_usable(struct wiphy *wiphy,
			     const struct cfg80211_chan_def *chandef,
			     u32 prohibited_flags)
{
	struct ieee80211_sta_ht_cap *ht_cap;
	struct ieee80211_sta_vht_cap *vht_cap;
	u32 width, control_freq;

	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
		return false;

	ht_cap = &wiphy->bands[chandef->chan->band]->ht_cap;
	vht_cap = &wiphy->bands[chandef->chan->band]->vht_cap;

	control_freq = chandef->chan->center_freq;

	switch (chandef->width) {
	case NL80211_CHAN_WIDTH_5:
		width = 5;
		break;
	case NL80211_CHAN_WIDTH_10:
		width = 10;
		break;
	case NL80211_CHAN_WIDTH_20:
		if (!ht_cap->ht_supported)
			return false;
	case NL80211_CHAN_WIDTH_20_NOHT:
		width = 20;
		break;
	case NL80211_CHAN_WIDTH_40:
		width = 40;
		if (!ht_cap->ht_supported)
			return false;
		if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)
			return false;
		if (chandef->center_freq1 < control_freq &&
		    chandef->chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
			return false;
		if (chandef->center_freq1 > control_freq &&
		    chandef->chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
			return false;
		break;
	case NL80211_CHAN_WIDTH_80P80:
		if (!(vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ))
			return false;
	case NL80211_CHAN_WIDTH_80:
		if (!vht_cap->vht_supported)
			return false;
		prohibited_flags |= IEEE80211_CHAN_NO_80MHZ;
		width = 80;
		break;
	case NL80211_CHAN_WIDTH_160:
		if (!vht_cap->vht_supported)
			return false;
		if (!(vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ))
			return false;
		prohibited_flags |= IEEE80211_CHAN_NO_160MHZ;
		width = 160;
		break;
	default:
		WARN_ON_ONCE(1);
		return false;
	}

	/*
	 * TODO: What if there are only certain 80/160/80+80 MHz channels
	 *	 allowed by the driver, or only certain combinations?
	 *	 For 40 MHz the driver can set the NO_HT40 flags, but for
	 *	 80/160 MHz and in particular 80+80 MHz this isn't really
	 *	 feasible and we only have NO_80MHZ/NO_160MHZ so far but
	 *	 no way to cover 80+80 MHz or more complex restrictions.
	 *	 Note that such restrictions also need to be advertised to
	 *	 userspace, for example for P2P channel selection.
	 */

	if (width > 20)
		prohibited_flags |= IEEE80211_CHAN_NO_OFDM;

	/* 5 and 10 MHz are only defined for the OFDM PHY */
	if (width < 20)
		prohibited_flags |= IEEE80211_CHAN_NO_OFDM;


	if (!cfg80211_secondary_chans_ok(wiphy, chandef->center_freq1,
					 width, prohibited_flags))
		return false;

	if (!chandef->center_freq2)
		return true;
	return cfg80211_secondary_chans_ok(wiphy, chandef->center_freq2,
					   width, prohibited_flags);
}
EXPORT_SYMBOL(cfg80211_chandef_usable);

bool cfg80211_reg_can_beacon(struct wiphy *wiphy,
			     struct cfg80211_chan_def *chandef)
{
	bool res;

	trace_cfg80211_reg_can_beacon(wiphy, chandef);

	res = cfg80211_chandef_usable(wiphy, chandef,
				      IEEE80211_CHAN_DISABLED |
				      IEEE80211_CHAN_PASSIVE_SCAN |
				      IEEE80211_CHAN_NO_IBSS |
				      IEEE80211_CHAN_RADAR);

	trace_cfg80211_return_bool(res);
	return res;
}
EXPORT_SYMBOL(cfg80211_reg_can_beacon);

int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
				 struct cfg80211_chan_def *chandef)
{
	if (!rdev->ops->set_monitor_channel)
		return -EOPNOTSUPP;
	if (!cfg80211_has_monitors_only(rdev))
		return -EBUSY;

	return rdev_set_monitor_channel(rdev, chandef);
}

void
cfg80211_get_chan_state(struct wireless_dev *wdev,
		        struct ieee80211_channel **chan,
		        enum cfg80211_chan_mode *chanmode)
{
	*chan = NULL;
	*chanmode = CHAN_MODE_UNDEFINED;

	ASSERT_WDEV_LOCK(wdev);

	if (wdev->netdev && !netif_running(wdev->netdev))
		return;

	switch (wdev->iftype) {
	case NL80211_IFTYPE_ADHOC:
		if (wdev->current_bss) {
			*chan = wdev->current_bss->pub.channel;
			*chanmode = wdev->ibss_fixed
				  ? CHAN_MODE_SHARED
				  : CHAN_MODE_EXCLUSIVE;
			return;
		}
	case NL80211_IFTYPE_STATION:
	case NL80211_IFTYPE_P2P_CLIENT:
		if (wdev->current_bss) {
			*chan = wdev->current_bss->pub.channel;
			*chanmode = CHAN_MODE_SHARED;
			return;
		}
		break;
	case NL80211_IFTYPE_AP:
	case NL80211_IFTYPE_P2P_GO:
		if (wdev->cac_started) {
			*chan = wdev->channel;
			*chanmode = CHAN_MODE_SHARED;
		} else if (wdev->beacon_interval) {
			*chan = wdev->channel;
			*chanmode = CHAN_MODE_SHARED;
		}
		return;
	case NL80211_IFTYPE_MESH_POINT:
		if (wdev->mesh_id_len) {
			*chan = wdev->channel;
			*chanmode = CHAN_MODE_SHARED;
		}
		return;
	case NL80211_IFTYPE_MONITOR:
	case NL80211_IFTYPE_AP_VLAN:
	case NL80211_IFTYPE_WDS:
		/* these interface types don't really have a channel */
		return;
	case NL80211_IFTYPE_P2P_DEVICE:
		if (wdev->wiphy->features &
				NL80211_FEATURE_P2P_DEVICE_NEEDS_CHANNEL)
			*chanmode = CHAN_MODE_EXCLUSIVE;
		return;
	case NL80211_IFTYPE_UNSPECIFIED:
	case NUM_NL80211_IFTYPES:
		WARN_ON(1);
	}

	return;
}