Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/drzeus/mmc
[linux-2.6] / net / mac80211 / util.c
1 /*
2  * Copyright 2002-2005, Instant802 Networks, Inc.
3  * Copyright 2005-2006, Devicescape Software, Inc.
4  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
5  * Copyright 2007       Johannes Berg <johannes@sipsolutions.net>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  * utilities for mac80211
12  */
13
14 #include <net/mac80211.h>
15 #include <linux/netdevice.h>
16 #include <linux/types.h>
17 #include <linux/slab.h>
18 #include <linux/skbuff.h>
19 #include <linux/etherdevice.h>
20 #include <linux/if_arp.h>
21 #include <linux/wireless.h>
22 #include <linux/bitmap.h>
23 #include <net/net_namespace.h>
24 #include <net/cfg80211.h>
25
26 #include "ieee80211_i.h"
27 #include "ieee80211_rate.h"
28 #include "wme.h"
29
30 /* privid for wiphys to determine whether they belong to us or not */
31 void *mac80211_wiphy_privid = &mac80211_wiphy_privid;
32
33 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
34 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
35 const unsigned char rfc1042_header[] =
36         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
37
38 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
39 const unsigned char bridge_tunnel_header[] =
40         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
41
42 /* No encapsulation header if EtherType < 0x600 (=length) */
43 static const unsigned char eapol_header[] =
44         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x88, 0x8e };
45
46
47 static int rate_list_match(const int *rate_list, int rate)
48 {
49         int i;
50
51         if (!rate_list)
52                 return 0;
53
54         for (i = 0; rate_list[i] >= 0; i++)
55                 if (rate_list[i] == rate)
56                         return 1;
57
58         return 0;
59 }
60
61 void ieee80211_prepare_rates(struct ieee80211_local *local,
62                              struct ieee80211_hw_mode *mode)
63 {
64         int i;
65
66         for (i = 0; i < mode->num_rates; i++) {
67                 struct ieee80211_rate *rate = &mode->rates[i];
68
69                 rate->flags &= ~(IEEE80211_RATE_SUPPORTED |
70                                  IEEE80211_RATE_BASIC);
71
72                 if (local->supp_rates[mode->mode]) {
73                         if (!rate_list_match(local->supp_rates[mode->mode],
74                                              rate->rate))
75                                 continue;
76                 }
77
78                 rate->flags |= IEEE80211_RATE_SUPPORTED;
79
80                 /* Use configured basic rate set if it is available. If not,
81                  * use defaults that are sane for most cases. */
82                 if (local->basic_rates[mode->mode]) {
83                         if (rate_list_match(local->basic_rates[mode->mode],
84                                             rate->rate))
85                                 rate->flags |= IEEE80211_RATE_BASIC;
86                 } else switch (mode->mode) {
87                 case MODE_IEEE80211A:
88                         if (rate->rate == 60 || rate->rate == 120 ||
89                             rate->rate == 240)
90                                 rate->flags |= IEEE80211_RATE_BASIC;
91                         break;
92                 case MODE_IEEE80211B:
93                         if (rate->rate == 10 || rate->rate == 20)
94                                 rate->flags |= IEEE80211_RATE_BASIC;
95                         break;
96                 case MODE_IEEE80211G:
97                         if (rate->rate == 10 || rate->rate == 20 ||
98                             rate->rate == 55 || rate->rate == 110)
99                                 rate->flags |= IEEE80211_RATE_BASIC;
100                         break;
101                 case NUM_IEEE80211_MODES:
102                         /* not useful */
103                         break;
104                 }
105
106                 /* Set ERP and MANDATORY flags based on phymode */
107                 switch (mode->mode) {
108                 case MODE_IEEE80211A:
109                         if (rate->rate == 60 || rate->rate == 120 ||
110                             rate->rate == 240)
111                                 rate->flags |= IEEE80211_RATE_MANDATORY;
112                         break;
113                 case MODE_IEEE80211B:
114                         if (rate->rate == 10)
115                                 rate->flags |= IEEE80211_RATE_MANDATORY;
116                         break;
117                 case MODE_IEEE80211G:
118                         if (rate->rate == 10 || rate->rate == 20 ||
119                             rate->rate == 55 || rate->rate == 110 ||
120                             rate->rate == 60 || rate->rate == 120 ||
121                             rate->rate == 240)
122                                 rate->flags |= IEEE80211_RATE_MANDATORY;
123                         break;
124                 case NUM_IEEE80211_MODES:
125                         /* not useful */
126                         break;
127                 }
128                 if (ieee80211_is_erp_rate(mode->mode, rate->rate))
129                         rate->flags |= IEEE80211_RATE_ERP;
130         }
131 }
132
133 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len)
134 {
135         u16 fc;
136
137         if (len < 24)
138                 return NULL;
139
140         fc = le16_to_cpu(hdr->frame_control);
141
142         switch (fc & IEEE80211_FCTL_FTYPE) {
143         case IEEE80211_FTYPE_DATA:
144                 switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
145                 case IEEE80211_FCTL_TODS:
146                         return hdr->addr1;
147                 case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
148                         return NULL;
149                 case IEEE80211_FCTL_FROMDS:
150                         return hdr->addr2;
151                 case 0:
152                         return hdr->addr3;
153                 }
154                 break;
155         case IEEE80211_FTYPE_MGMT:
156                 return hdr->addr3;
157         case IEEE80211_FTYPE_CTL:
158                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
159                         return hdr->addr1;
160                 else
161                         return NULL;
162         }
163
164         return NULL;
165 }
166
167 int ieee80211_get_hdrlen(u16 fc)
168 {
169         int hdrlen = 24;
170
171         switch (fc & IEEE80211_FCTL_FTYPE) {
172         case IEEE80211_FTYPE_DATA:
173                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
174                         hdrlen = 30; /* Addr4 */
175                 /*
176                  * The QoS Control field is two bytes and its presence is
177                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
178                  * hdrlen if that bit is set.
179                  * This works by masking out the bit and shifting it to
180                  * bit position 1 so the result has the value 0 or 2.
181                  */
182                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
183                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
184                 break;
185         case IEEE80211_FTYPE_CTL:
186                 /*
187                  * ACK and CTS are 10 bytes, all others 16. To see how
188                  * to get this condition consider
189                  *   subtype mask:   0b0000000011110000 (0x00F0)
190                  *   ACK subtype:    0b0000000011010000 (0x00D0)
191                  *   CTS subtype:    0b0000000011000000 (0x00C0)
192                  *   bits that matter:         ^^^      (0x00E0)
193                  *   value of those: 0b0000000011000000 (0x00C0)
194                  */
195                 if ((fc & 0xE0) == 0xC0)
196                         hdrlen = 10;
197                 else
198                         hdrlen = 16;
199                 break;
200         }
201
202         return hdrlen;
203 }
204 EXPORT_SYMBOL(ieee80211_get_hdrlen);
205
206 int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
207 {
208         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
209         int hdrlen;
210
211         if (unlikely(skb->len < 10))
212                 return 0;
213         hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
214         if (unlikely(hdrlen > skb->len))
215                 return 0;
216         return hdrlen;
217 }
218 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
219
220 int ieee80211_is_eapol(const struct sk_buff *skb)
221 {
222         const struct ieee80211_hdr *hdr;
223         u16 fc;
224         int hdrlen;
225
226         if (unlikely(skb->len < 10))
227                 return 0;
228
229         hdr = (const struct ieee80211_hdr *) skb->data;
230         fc = le16_to_cpu(hdr->frame_control);
231
232         if (unlikely(!WLAN_FC_DATA_PRESENT(fc)))
233                 return 0;
234
235         hdrlen = ieee80211_get_hdrlen(fc);
236
237         if (unlikely(skb->len >= hdrlen + sizeof(eapol_header) &&
238                      memcmp(skb->data + hdrlen, eapol_header,
239                             sizeof(eapol_header)) == 0))
240                 return 1;
241
242         return 0;
243 }
244
245 void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
246 {
247         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
248
249         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
250         if (tx->u.tx.extra_frag) {
251                 struct ieee80211_hdr *fhdr;
252                 int i;
253                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
254                         fhdr = (struct ieee80211_hdr *)
255                                 tx->u.tx.extra_frag[i]->data;
256                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
257                 }
258         }
259 }
260
261 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
262                              int rate, int erp, int short_preamble)
263 {
264         int dur;
265
266         /* calculate duration (in microseconds, rounded up to next higher
267          * integer if it includes a fractional microsecond) to send frame of
268          * len bytes (does not include FCS) at the given rate. Duration will
269          * also include SIFS.
270          *
271          * rate is in 100 kbps, so divident is multiplied by 10 in the
272          * DIV_ROUND_UP() operations.
273          */
274
275         if (local->hw.conf.phymode == MODE_IEEE80211A || erp) {
276                 /*
277                  * OFDM:
278                  *
279                  * N_DBPS = DATARATE x 4
280                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
281                  *      (16 = SIGNAL time, 6 = tail bits)
282                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
283                  *
284                  * T_SYM = 4 usec
285                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
286                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
287                  *      signal ext = 6 usec
288                  */
289                 dur = 16; /* SIFS + signal ext */
290                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
291                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
292                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
293                                         4 * rate); /* T_SYM x N_SYM */
294         } else {
295                 /*
296                  * 802.11b or 802.11g with 802.11b compatibility:
297                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
298                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
299                  *
300                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
301                  * aSIFSTime = 10 usec
302                  * aPreambleLength = 144 usec or 72 usec with short preamble
303                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
304                  */
305                 dur = 10; /* aSIFSTime = 10 usec */
306                 dur += short_preamble ? (72 + 24) : (144 + 48);
307
308                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
309         }
310
311         return dur;
312 }
313
314 /* Exported duration function for driver use */
315 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, int if_id,
316                                         size_t frame_len, int rate)
317 {
318         struct ieee80211_local *local = hw_to_local(hw);
319         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
320         struct ieee80211_sub_if_data *sdata;
321         u16 dur;
322         int erp;
323
324         if (unlikely(!bdev))
325                 return 0;
326
327         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
328         erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
329         dur = ieee80211_frame_duration(local, frame_len, rate,
330                        erp, sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE);
331
332         dev_put(bdev);
333         return cpu_to_le16(dur);
334 }
335 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
336
337 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw, int if_id,
338                               size_t frame_len,
339                               const struct ieee80211_tx_control *frame_txctl)
340 {
341         struct ieee80211_local *local = hw_to_local(hw);
342         struct ieee80211_rate *rate;
343         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
344         struct ieee80211_sub_if_data *sdata;
345         int short_preamble;
346         int erp;
347         u16 dur;
348
349         if (unlikely(!bdev))
350                 return 0;
351
352         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
353         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
354
355         rate = frame_txctl->rts_rate;
356         erp = !!(rate->flags & IEEE80211_RATE_ERP);
357
358         /* CTS duration */
359         dur = ieee80211_frame_duration(local, 10, rate->rate,
360                                        erp, short_preamble);
361         /* Data frame duration */
362         dur += ieee80211_frame_duration(local, frame_len, rate->rate,
363                                         erp, short_preamble);
364         /* ACK duration */
365         dur += ieee80211_frame_duration(local, 10, rate->rate,
366                                         erp, short_preamble);
367
368         dev_put(bdev);
369         return cpu_to_le16(dur);
370 }
371 EXPORT_SYMBOL(ieee80211_rts_duration);
372
373 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, int if_id,
374                                     size_t frame_len,
375                                     const struct ieee80211_tx_control *frame_txctl)
376 {
377         struct ieee80211_local *local = hw_to_local(hw);
378         struct ieee80211_rate *rate;
379         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
380         struct ieee80211_sub_if_data *sdata;
381         int short_preamble;
382         int erp;
383         u16 dur;
384
385         if (unlikely(!bdev))
386                 return 0;
387
388         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
389         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
390
391         rate = frame_txctl->rts_rate;
392         erp = !!(rate->flags & IEEE80211_RATE_ERP);
393
394         /* Data frame duration */
395         dur = ieee80211_frame_duration(local, frame_len, rate->rate,
396                                        erp, short_preamble);
397         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
398                 /* ACK duration */
399                 dur += ieee80211_frame_duration(local, 10, rate->rate,
400                                                 erp, short_preamble);
401         }
402
403         dev_put(bdev);
404         return cpu_to_le16(dur);
405 }
406 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
407
408 struct ieee80211_rate *
409 ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
410 {
411         struct ieee80211_hw_mode *mode;
412         int r;
413
414         list_for_each_entry(mode, &local->modes_list, list) {
415                 if (mode->mode != phymode)
416                         continue;
417                 for (r = 0; r < mode->num_rates; r++) {
418                         struct ieee80211_rate *rate = &mode->rates[r];
419                         if (rate->val == hw_rate ||
420                             (rate->flags & IEEE80211_RATE_PREAMBLE2 &&
421                              rate->val2 == hw_rate))
422                                 return rate;
423                 }
424         }
425
426         return NULL;
427 }
428
429 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
430 {
431         struct ieee80211_local *local = hw_to_local(hw);
432
433         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
434                                &local->state[queue])) {
435                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
436                              &local->state[queue]))
437                         tasklet_schedule(&local->tx_pending_tasklet);
438                 else
439                         if (!ieee80211_qdisc_installed(local->mdev)) {
440                                 if (queue == 0)
441                                         netif_wake_queue(local->mdev);
442                         } else
443                                 __netif_schedule(local->mdev);
444         }
445 }
446 EXPORT_SYMBOL(ieee80211_wake_queue);
447
448 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
449 {
450         struct ieee80211_local *local = hw_to_local(hw);
451
452         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
453                 netif_stop_queue(local->mdev);
454         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
455 }
456 EXPORT_SYMBOL(ieee80211_stop_queue);
457
458 void ieee80211_start_queues(struct ieee80211_hw *hw)
459 {
460         struct ieee80211_local *local = hw_to_local(hw);
461         int i;
462
463         for (i = 0; i < local->hw.queues; i++)
464                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
465         if (!ieee80211_qdisc_installed(local->mdev))
466                 netif_start_queue(local->mdev);
467 }
468 EXPORT_SYMBOL(ieee80211_start_queues);
469
470 void ieee80211_stop_queues(struct ieee80211_hw *hw)
471 {
472         int i;
473
474         for (i = 0; i < hw->queues; i++)
475                 ieee80211_stop_queue(hw, i);
476 }
477 EXPORT_SYMBOL(ieee80211_stop_queues);
478
479 void ieee80211_wake_queues(struct ieee80211_hw *hw)
480 {
481         int i;
482
483         for (i = 0; i < hw->queues; i++)
484                 ieee80211_wake_queue(hw, i);
485 }
486 EXPORT_SYMBOL(ieee80211_wake_queues);