Merge branches 'release' and 'hp-cid' into release
[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 #include <net/rtnetlink.h>
26
27 #include "ieee80211_i.h"
28 #include "ieee80211_rate.h"
29 #include "wme.h"
30
31 /* privid for wiphys to determine whether they belong to us or not */
32 void *mac80211_wiphy_privid = &mac80211_wiphy_privid;
33
34 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
35 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
36 const unsigned char rfc1042_header[] =
37         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
38
39 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
40 const unsigned char bridge_tunnel_header[] =
41         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
42
43
44 static int rate_list_match(const int *rate_list, int rate)
45 {
46         int i;
47
48         if (!rate_list)
49                 return 0;
50
51         for (i = 0; rate_list[i] >= 0; i++)
52                 if (rate_list[i] == rate)
53                         return 1;
54
55         return 0;
56 }
57
58 void ieee80211_prepare_rates(struct ieee80211_local *local,
59                              struct ieee80211_hw_mode *mode)
60 {
61         int i;
62
63         for (i = 0; i < mode->num_rates; i++) {
64                 struct ieee80211_rate *rate = &mode->rates[i];
65
66                 rate->flags &= ~(IEEE80211_RATE_SUPPORTED |
67                                  IEEE80211_RATE_BASIC);
68
69                 if (local->supp_rates[mode->mode]) {
70                         if (!rate_list_match(local->supp_rates[mode->mode],
71                                              rate->rate))
72                                 continue;
73                 }
74
75                 rate->flags |= IEEE80211_RATE_SUPPORTED;
76
77                 /* Use configured basic rate set if it is available. If not,
78                  * use defaults that are sane for most cases. */
79                 if (local->basic_rates[mode->mode]) {
80                         if (rate_list_match(local->basic_rates[mode->mode],
81                                             rate->rate))
82                                 rate->flags |= IEEE80211_RATE_BASIC;
83                 } else switch (mode->mode) {
84                 case MODE_IEEE80211A:
85                         if (rate->rate == 60 || rate->rate == 120 ||
86                             rate->rate == 240)
87                                 rate->flags |= IEEE80211_RATE_BASIC;
88                         break;
89                 case MODE_IEEE80211B:
90                         if (rate->rate == 10 || rate->rate == 20)
91                                 rate->flags |= IEEE80211_RATE_BASIC;
92                         break;
93                 case MODE_IEEE80211G:
94                         if (rate->rate == 10 || rate->rate == 20 ||
95                             rate->rate == 55 || rate->rate == 110)
96                                 rate->flags |= IEEE80211_RATE_BASIC;
97                         break;
98                 case NUM_IEEE80211_MODES:
99                         /* not useful */
100                         break;
101                 }
102
103                 /* Set ERP and MANDATORY flags based on phymode */
104                 switch (mode->mode) {
105                 case MODE_IEEE80211A:
106                         if (rate->rate == 60 || rate->rate == 120 ||
107                             rate->rate == 240)
108                                 rate->flags |= IEEE80211_RATE_MANDATORY;
109                         break;
110                 case MODE_IEEE80211B:
111                         if (rate->rate == 10)
112                                 rate->flags |= IEEE80211_RATE_MANDATORY;
113                         break;
114                 case MODE_IEEE80211G:
115                         if (rate->rate == 10 || rate->rate == 20 ||
116                             rate->rate == 55 || rate->rate == 110 ||
117                             rate->rate == 60 || rate->rate == 120 ||
118                             rate->rate == 240)
119                                 rate->flags |= IEEE80211_RATE_MANDATORY;
120                         break;
121                 case NUM_IEEE80211_MODES:
122                         /* not useful */
123                         break;
124                 }
125                 if (ieee80211_is_erp_rate(mode->mode, rate->rate))
126                         rate->flags |= IEEE80211_RATE_ERP;
127         }
128 }
129
130 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
131                         enum ieee80211_if_types type)
132 {
133         u16 fc;
134
135          /* drop ACK/CTS frames and incorrect hdr len (ctrl) */
136         if (len < 16)
137                 return NULL;
138
139         fc = le16_to_cpu(hdr->frame_control);
140
141         switch (fc & IEEE80211_FCTL_FTYPE) {
142         case IEEE80211_FTYPE_DATA:
143                 if (len < 24) /* drop incorrect hdr len (data) */
144                         return NULL;
145                 switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
146                 case IEEE80211_FCTL_TODS:
147                         return hdr->addr1;
148                 case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
149                         return NULL;
150                 case IEEE80211_FCTL_FROMDS:
151                         return hdr->addr2;
152                 case 0:
153                         return hdr->addr3;
154                 }
155                 break;
156         case IEEE80211_FTYPE_MGMT:
157                 if (len < 24) /* drop incorrect hdr len (mgmt) */
158                         return NULL;
159                 return hdr->addr3;
160         case IEEE80211_FTYPE_CTL:
161                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
162                         return hdr->addr1;
163                 else if ((fc & IEEE80211_FCTL_STYPE) ==
164                                                 IEEE80211_STYPE_BACK_REQ) {
165                         switch (type) {
166                         case IEEE80211_IF_TYPE_STA:
167                                 return hdr->addr2;
168                         case IEEE80211_IF_TYPE_AP:
169                         case IEEE80211_IF_TYPE_VLAN:
170                                 return hdr->addr1;
171                         default:
172                                 return NULL;
173                         }
174                 }
175                 else
176                         return NULL;
177         }
178
179         return NULL;
180 }
181
182 int ieee80211_get_hdrlen(u16 fc)
183 {
184         int hdrlen = 24;
185
186         switch (fc & IEEE80211_FCTL_FTYPE) {
187         case IEEE80211_FTYPE_DATA:
188                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
189                         hdrlen = 30; /* Addr4 */
190                 /*
191                  * The QoS Control field is two bytes and its presence is
192                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
193                  * hdrlen if that bit is set.
194                  * This works by masking out the bit and shifting it to
195                  * bit position 1 so the result has the value 0 or 2.
196                  */
197                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
198                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
199                 break;
200         case IEEE80211_FTYPE_CTL:
201                 /*
202                  * ACK and CTS are 10 bytes, all others 16. To see how
203                  * to get this condition consider
204                  *   subtype mask:   0b0000000011110000 (0x00F0)
205                  *   ACK subtype:    0b0000000011010000 (0x00D0)
206                  *   CTS subtype:    0b0000000011000000 (0x00C0)
207                  *   bits that matter:         ^^^      (0x00E0)
208                  *   value of those: 0b0000000011000000 (0x00C0)
209                  */
210                 if ((fc & 0xE0) == 0xC0)
211                         hdrlen = 10;
212                 else
213                         hdrlen = 16;
214                 break;
215         }
216
217         return hdrlen;
218 }
219 EXPORT_SYMBOL(ieee80211_get_hdrlen);
220
221 int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
222 {
223         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
224         int hdrlen;
225
226         if (unlikely(skb->len < 10))
227                 return 0;
228         hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
229         if (unlikely(hdrlen > skb->len))
230                 return 0;
231         return hdrlen;
232 }
233 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
234
235 void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
236 {
237         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
238
239         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
240         if (tx->u.tx.extra_frag) {
241                 struct ieee80211_hdr *fhdr;
242                 int i;
243                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
244                         fhdr = (struct ieee80211_hdr *)
245                                 tx->u.tx.extra_frag[i]->data;
246                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
247                 }
248         }
249 }
250
251 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
252                              int rate, int erp, int short_preamble)
253 {
254         int dur;
255
256         /* calculate duration (in microseconds, rounded up to next higher
257          * integer if it includes a fractional microsecond) to send frame of
258          * len bytes (does not include FCS) at the given rate. Duration will
259          * also include SIFS.
260          *
261          * rate is in 100 kbps, so divident is multiplied by 10 in the
262          * DIV_ROUND_UP() operations.
263          */
264
265         if (local->hw.conf.phymode == MODE_IEEE80211A || erp) {
266                 /*
267                  * OFDM:
268                  *
269                  * N_DBPS = DATARATE x 4
270                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
271                  *      (16 = SIGNAL time, 6 = tail bits)
272                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
273                  *
274                  * T_SYM = 4 usec
275                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
276                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
277                  *      signal ext = 6 usec
278                  */
279                 dur = 16; /* SIFS + signal ext */
280                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
281                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
282                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
283                                         4 * rate); /* T_SYM x N_SYM */
284         } else {
285                 /*
286                  * 802.11b or 802.11g with 802.11b compatibility:
287                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
288                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
289                  *
290                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
291                  * aSIFSTime = 10 usec
292                  * aPreambleLength = 144 usec or 72 usec with short preamble
293                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
294                  */
295                 dur = 10; /* aSIFSTime = 10 usec */
296                 dur += short_preamble ? (72 + 24) : (144 + 48);
297
298                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
299         }
300
301         return dur;
302 }
303
304 /* Exported duration function for driver use */
305 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
306                                         struct ieee80211_vif *vif,
307                                         size_t frame_len, int rate)
308 {
309         struct ieee80211_local *local = hw_to_local(hw);
310         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
311         u16 dur;
312         int erp;
313
314         erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
315         dur = ieee80211_frame_duration(local, frame_len, rate, erp,
316                                        sdata->bss_conf.use_short_preamble);
317
318         return cpu_to_le16(dur);
319 }
320 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
321
322 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
323                               struct ieee80211_vif *vif, size_t frame_len,
324                               const struct ieee80211_tx_control *frame_txctl)
325 {
326         struct ieee80211_local *local = hw_to_local(hw);
327         struct ieee80211_rate *rate;
328         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
329         bool short_preamble;
330         int erp;
331         u16 dur;
332
333         short_preamble = sdata->bss_conf.use_short_preamble;
334
335         rate = frame_txctl->rts_rate;
336         erp = !!(rate->flags & IEEE80211_RATE_ERP);
337
338         /* CTS duration */
339         dur = ieee80211_frame_duration(local, 10, rate->rate,
340                                        erp, short_preamble);
341         /* Data frame duration */
342         dur += ieee80211_frame_duration(local, frame_len, rate->rate,
343                                         erp, short_preamble);
344         /* ACK duration */
345         dur += ieee80211_frame_duration(local, 10, rate->rate,
346                                         erp, short_preamble);
347
348         return cpu_to_le16(dur);
349 }
350 EXPORT_SYMBOL(ieee80211_rts_duration);
351
352 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
353                                     struct ieee80211_vif *vif,
354                                     size_t frame_len,
355                                     const struct ieee80211_tx_control *frame_txctl)
356 {
357         struct ieee80211_local *local = hw_to_local(hw);
358         struct ieee80211_rate *rate;
359         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
360         bool short_preamble;
361         int erp;
362         u16 dur;
363
364         short_preamble = sdata->bss_conf.use_short_preamble;
365
366         rate = frame_txctl->rts_rate;
367         erp = !!(rate->flags & IEEE80211_RATE_ERP);
368
369         /* Data frame duration */
370         dur = ieee80211_frame_duration(local, frame_len, rate->rate,
371                                        erp, short_preamble);
372         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
373                 /* ACK duration */
374                 dur += ieee80211_frame_duration(local, 10, rate->rate,
375                                                 erp, short_preamble);
376         }
377
378         return cpu_to_le16(dur);
379 }
380 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
381
382 struct ieee80211_rate *
383 ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
384 {
385         struct ieee80211_hw_mode *mode;
386         int r;
387
388         list_for_each_entry(mode, &local->modes_list, list) {
389                 if (mode->mode != phymode)
390                         continue;
391                 for (r = 0; r < mode->num_rates; r++) {
392                         struct ieee80211_rate *rate = &mode->rates[r];
393                         if (rate->val == hw_rate ||
394                             (rate->flags & IEEE80211_RATE_PREAMBLE2 &&
395                              rate->val2 == hw_rate))
396                                 return rate;
397                 }
398         }
399
400         return NULL;
401 }
402
403 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
404 {
405         struct ieee80211_local *local = hw_to_local(hw);
406
407         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
408                                &local->state[queue])) {
409                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
410                              &local->state[queue]))
411                         tasklet_schedule(&local->tx_pending_tasklet);
412                 else
413                         if (!ieee80211_qdisc_installed(local->mdev)) {
414                                 if (queue == 0)
415                                         netif_wake_queue(local->mdev);
416                         } else
417                                 __netif_schedule(local->mdev);
418         }
419 }
420 EXPORT_SYMBOL(ieee80211_wake_queue);
421
422 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
423 {
424         struct ieee80211_local *local = hw_to_local(hw);
425
426         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
427                 netif_stop_queue(local->mdev);
428         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
429 }
430 EXPORT_SYMBOL(ieee80211_stop_queue);
431
432 void ieee80211_start_queues(struct ieee80211_hw *hw)
433 {
434         struct ieee80211_local *local = hw_to_local(hw);
435         int i;
436
437         for (i = 0; i < local->hw.queues; i++)
438                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
439         if (!ieee80211_qdisc_installed(local->mdev))
440                 netif_start_queue(local->mdev);
441 }
442 EXPORT_SYMBOL(ieee80211_start_queues);
443
444 void ieee80211_stop_queues(struct ieee80211_hw *hw)
445 {
446         int i;
447
448         for (i = 0; i < hw->queues; i++)
449                 ieee80211_stop_queue(hw, i);
450 }
451 EXPORT_SYMBOL(ieee80211_stop_queues);
452
453 void ieee80211_wake_queues(struct ieee80211_hw *hw)
454 {
455         int i;
456
457         for (i = 0; i < hw->queues; i++)
458                 ieee80211_wake_queue(hw, i);
459 }
460 EXPORT_SYMBOL(ieee80211_wake_queues);
461
462 void ieee80211_iterate_active_interfaces(
463         struct ieee80211_hw *hw,
464         void (*iterator)(void *data, u8 *mac,
465                          struct ieee80211_vif *vif),
466         void *data)
467 {
468         struct ieee80211_local *local = hw_to_local(hw);
469         struct ieee80211_sub_if_data *sdata;
470
471         rcu_read_lock();
472
473         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
474                 switch (sdata->vif.type) {
475                 case IEEE80211_IF_TYPE_INVALID:
476                 case IEEE80211_IF_TYPE_MNTR:
477                 case IEEE80211_IF_TYPE_VLAN:
478                         continue;
479                 case IEEE80211_IF_TYPE_AP:
480                 case IEEE80211_IF_TYPE_STA:
481                 case IEEE80211_IF_TYPE_IBSS:
482                 case IEEE80211_IF_TYPE_WDS:
483                         break;
484                 }
485                 if (sdata->dev == local->mdev)
486                         continue;
487                 if (netif_running(sdata->dev))
488                         iterator(data, sdata->dev->dev_addr,
489                                  &sdata->vif);
490         }
491
492         rcu_read_unlock();
493 }
494 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);