summaryrefslogtreecommitdiffstats
path: root/net/mac80211/util.c
blob: 07686bda26cdae55952ad4e55ae1329d3cb2fd83 (plain)
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
/*
 * 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/cfg80211.h>

#include "ieee80211_i.h"
#include "ieee80211_rate.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[] =
	{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };

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

/* No encapsulation header if EtherType < 0x600 (=length) */
static const unsigned char eapol_header[] =
	{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x88, 0x8e };


static int rate_list_match(const int *rate_list, int rate)
{
	int i;

	if (!rate_list)
		return 0;

	for (i = 0; rate_list[i] >= 0; i++)
		if (rate_list[i] == rate)
			return 1;

	return 0;
}

void ieee80211_prepare_rates(struct ieee80211_local *local,
			     struct ieee80211_hw_mode *mode)
{
	int i;

	for (i = 0; i < mode->num_rates; i++) {
		struct ieee80211_rate *rate = &mode->rates[i];

		rate->flags &= ~(IEEE80211_RATE_SUPPORTED |
				 IEEE80211_RATE_BASIC);

		if (local->supp_rates[mode->mode]) {
			if (!rate_list_match(local->supp_rates[mode->mode],
					     rate->rate))
				continue;
		}

		rate->flags |= IEEE80211_RATE_SUPPORTED;

		/* Use configured basic rate set if it is available. If not,
		 * use defaults that are sane for most cases. */
		if (local->basic_rates[mode->mode]) {
			if (rate_list_match(local->basic_rates[mode->mode],
					    rate->rate))
				rate->flags |= IEEE80211_RATE_BASIC;
		} else switch (mode->mode) {
		case MODE_IEEE80211A:
			if (rate->rate == 60 || rate->rate == 120 ||
			    rate->rate == 240)
				rate->flags |= IEEE80211_RATE_BASIC;
			break;
		case MODE_IEEE80211B:
			if (rate->rate == 10 || rate->rate == 20)
				rate->flags |= IEEE80211_RATE_BASIC;
			break;
		case MODE_ATHEROS_TURBO:
			if (rate->rate == 120 || rate->rate == 240 ||
			    rate->rate == 480)
				rate->flags |= IEEE80211_RATE_BASIC;
			break;
		case MODE_IEEE80211G:
			if (rate->rate == 10 || rate->rate == 20 ||
			    rate->rate == 55 || rate->rate == 110)
				rate->flags |= IEEE80211_RATE_BASIC;
			break;
		}

		/* Set ERP and MANDATORY flags based on phymode */
		switch (mode->mode) {
		case MODE_IEEE80211A:
			if (rate->rate == 60 || rate->rate == 120 ||
			    rate->rate == 240)
				rate->flags |= IEEE80211_RATE_MANDATORY;
			break;
		case MODE_IEEE80211B:
			if (rate->rate == 10)
				rate->flags |= IEEE80211_RATE_MANDATORY;
			break;
		case MODE_ATHEROS_TURBO:
			break;
		case MODE_IEEE80211G:
			if (rate->rate == 10 || rate->rate == 20 ||
			    rate->rate == 55 || rate->rate == 110 ||
			    rate->rate == 60 || rate->rate == 120 ||
			    rate->rate == 240)
				rate->flags |= IEEE80211_RATE_MANDATORY;
			break;
		}
		if (ieee80211_is_erp_rate(mode->mode, rate->rate))
			rate->flags |= IEEE80211_RATE_ERP;
	}
}

u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len)
{
	u16 fc;

	if (len < 24)
		return NULL;

	fc = le16_to_cpu(hdr->frame_control);

	switch (fc & IEEE80211_FCTL_FTYPE) {
	case IEEE80211_FTYPE_DATA:
		switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
		case IEEE80211_FCTL_TODS:
			return hdr->addr1;
		case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
			return NULL;
		case IEEE80211_FCTL_FROMDS:
			return hdr->addr2;
		case 0:
			return hdr->addr3;
		}
		break;
	case IEEE80211_FTYPE_MGMT:
		return hdr->addr3;
	case IEEE80211_FTYPE_CTL:
		if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
			return hdr->addr1;
		else
			return NULL;
	}

	return NULL;
}

int ieee80211_get_hdrlen(u16 fc)
{
	int hdrlen = 24;

	switch (fc & IEEE80211_FCTL_FTYPE) {
	case IEEE80211_FTYPE_DATA:
		if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
			hdrlen = 30; /* Addr4 */
		/*
		 * The QoS Control field is two bytes and its presence is
		 * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
		 * hdrlen if that bit is set.
		 * This works by masking out the bit and shifting it to
		 * bit position 1 so the result has the value 0 or 2.
		 */
		hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
				>> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
		break;
	case IEEE80211_FTYPE_CTL:
		/*
		 * 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 & 0xE0) == 0xC0)
			hdrlen = 10;
		else
			hdrlen = 16;
		break;
	}

	return hdrlen;
}
EXPORT_SYMBOL(ieee80211_get_hdrlen);

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

	if (unlikely(skb->len < 10))
		return 0;
	hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
	if (unlikely(hdrlen > skb->len))
		return 0;
	return hdrlen;
}
EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);

int ieee80211_is_eapol(const struct sk_buff *skb)
{
	const struct ieee80211_hdr *hdr;
	u16 fc;
	int hdrlen;

	if (unlikely(skb->len < 10))
		return 0;

	hdr = (const struct ieee80211_hdr *) skb->data;
	fc = le16_to_cpu(hdr->frame_control);

	if (unlikely(!WLAN_FC_DATA_PRESENT(fc)))
		return 0;

	hdrlen = ieee80211_get_hdrlen(fc);

	if (unlikely(skb->len >= hdrlen + sizeof(eapol_header) &&
		     memcmp(skb->data + hdrlen, eapol_header,
			    sizeof(eapol_header)) == 0))
		return 1;

	return 0;
}

void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
{
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;

	hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
	if (tx->u.tx.extra_frag) {
		struct ieee80211_hdr *fhdr;
		int i;
		for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
			fhdr = (struct ieee80211_hdr *)
				tx->u.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.phymode == MODE_IEEE80211A || erp ||
	    local->hw.conf.phymode == MODE_ATHEROS_TURBO) {
		/*
		 * 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
		 */
		/* FIX: Atheros Turbo may have different (shorter) duration? */
		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, int if_id,
					size_t frame_len, int rate)
{
	struct ieee80211_local *local = hw_to_local(hw);
	struct net_device *bdev = dev_get_by_index(if_id);
	struct ieee80211_sub_if_data *sdata;
	u16 dur;
	int erp;

	if (unlikely(!bdev))
		return 0;

	sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
	erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
	dur = ieee80211_frame_duration(local, frame_len, rate,
		       erp, sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE);

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

__le16 ieee80211_rts_duration(struct ieee80211_hw *hw, int if_id,
			      size_t frame_len,
			      const struct ieee80211_tx_control *frame_txctl)
{
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_rate *rate;
	struct net_device *bdev = dev_get_by_index(if_id);
	struct ieee80211_sub_if_data *sdata;
	int short_preamble;
	int erp;
	u16 dur;

	if (unlikely(!bdev))
		return 0;

	sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
	short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;

	rate = frame_txctl->rts_rate;
	erp = !!(rate->flags & IEEE80211_RATE_ERP);

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

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

__le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, int if_id,
				    size_t frame_len,
				    const struct ieee80211_tx_control *frame_txctl)
{
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_rate *rate;
	struct net_device *bdev = dev_get_by_index(if_id);
	struct ieee80211_sub_if_data *sdata;
	int short_preamble;
	int erp;
	u16 dur;

	if (unlikely(!bdev))
		return 0;

	sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
	short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;

	rate = frame_txctl->rts_rate;
	erp = !!(rate->flags & IEEE80211_RATE_ERP);

	/* Data frame duration */
	dur = ieee80211_frame_duration(local, frame_len, rate->rate,
				       erp, short_preamble);
	if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
		/* ACK duration */
		dur += ieee80211_frame_duration(local, 10, rate->rate,
						erp, short_preamble);
	}

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

struct ieee80211_rate *
ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
{
	struct ieee80211_hw_mode *mode;
	int r;

	list_for_each_entry(mode, &local->modes_list, list) {
		if (mode->mode != phymode)
			continue;
		for (r = 0; r < mode->num_rates; r++) {
			struct ieee80211_rate *rate = &mode->rates[r];
			if (rate->val == hw_rate ||
			    (rate->flags & IEEE80211_RATE_PREAMBLE2 &&
			     rate->val2 == hw_rate))
				return rate;
		}
	}

	return NULL;
}

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

	if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
			       &local->state[queue])) {
		if (test_bit(IEEE80211_LINK_STATE_PENDING,
			     &local->state[queue]))
			tasklet_schedule(&local->tx_pending_tasklet);
		else
			if (!ieee80211_qdisc_installed(local->mdev)) {
				if (queue == 0)
					netif_wake_queue(local->mdev);
			} else
				__netif_schedule(local->mdev);
	}
}
EXPORT_SYMBOL(ieee80211_wake_queue);

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

	if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
		netif_stop_queue(local->mdev);
	set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
}
EXPORT_SYMBOL(ieee80211_stop_queue);

void ieee80211_start_queues(struct ieee80211_hw *hw)
{
	struct ieee80211_local *local = hw_to_local(hw);
	int i;

	for (i = 0; i < local->hw.queues; i++)
		clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
	if (!ieee80211_qdisc_installed(local->mdev))
		netif_start_queue(local->mdev);
}
EXPORT_SYMBOL(ieee80211_start_queues);

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

	for (i = 0; i < hw->queues; i++)
		ieee80211_stop_queue(hw, i);
}
EXPORT_SYMBOL(ieee80211_stop_queues);

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

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