dccp: Auto-load (when supported) CCID plugins for negotiation
[linux-2.6.git] / 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 "rate.h"
29 #include "mesh.h"
30 #include "wme.h"
31
32 /* privid for wiphys to determine whether they belong to us or not */
33 void *mac80211_wiphy_privid = &mac80211_wiphy_privid;
34
35 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
36 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
37 const unsigned char rfc1042_header[] __aligned(2) =
38         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
39
40 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
41 const unsigned char bridge_tunnel_header[] __aligned(2) =
42         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
43
44
45 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
46                         enum ieee80211_if_types type)
47 {
48         __le16 fc = hdr->frame_control;
49
50          /* drop ACK/CTS frames and incorrect hdr len (ctrl) */
51         if (len < 16)
52                 return NULL;
53
54         if (ieee80211_is_data(fc)) {
55                 if (len < 24) /* drop incorrect hdr len (data) */
56                         return NULL;
57
58                 if (ieee80211_has_a4(fc))
59                         return NULL;
60                 if (ieee80211_has_tods(fc))
61                         return hdr->addr1;
62                 if (ieee80211_has_fromds(fc))
63                         return hdr->addr2;
64
65                 return hdr->addr3;
66         }
67
68         if (ieee80211_is_mgmt(fc)) {
69                 if (len < 24) /* drop incorrect hdr len (mgmt) */
70                         return NULL;
71                 return hdr->addr3;
72         }
73
74         if (ieee80211_is_ctl(fc)) {
75                 if(ieee80211_is_pspoll(fc))
76                         return hdr->addr1;
77
78                 if (ieee80211_is_back_req(fc)) {
79                         switch (type) {
80                         case IEEE80211_IF_TYPE_STA:
81                                 return hdr->addr2;
82                         case IEEE80211_IF_TYPE_AP:
83                         case IEEE80211_IF_TYPE_VLAN:
84                                 return hdr->addr1;
85                         default:
86                                 break; /* fall through to the return */
87                         }
88                 }
89         }
90
91         return NULL;
92 }
93
94 int ieee80211_get_hdrlen(u16 fc)
95 {
96         int hdrlen = 24;
97
98         switch (fc & IEEE80211_FCTL_FTYPE) {
99         case IEEE80211_FTYPE_DATA:
100                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
101                         hdrlen = 30; /* Addr4 */
102                 /*
103                  * The QoS Control field is two bytes and its presence is
104                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
105                  * hdrlen if that bit is set.
106                  * This works by masking out the bit and shifting it to
107                  * bit position 1 so the result has the value 0 or 2.
108                  */
109                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
110                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
111                 break;
112         case IEEE80211_FTYPE_CTL:
113                 /*
114                  * ACK and CTS are 10 bytes, all others 16. To see how
115                  * to get this condition consider
116                  *   subtype mask:   0b0000000011110000 (0x00F0)
117                  *   ACK subtype:    0b0000000011010000 (0x00D0)
118                  *   CTS subtype:    0b0000000011000000 (0x00C0)
119                  *   bits that matter:         ^^^      (0x00E0)
120                  *   value of those: 0b0000000011000000 (0x00C0)
121                  */
122                 if ((fc & 0xE0) == 0xC0)
123                         hdrlen = 10;
124                 else
125                         hdrlen = 16;
126                 break;
127         }
128
129         return hdrlen;
130 }
131 EXPORT_SYMBOL(ieee80211_get_hdrlen);
132
133 unsigned int ieee80211_hdrlen(__le16 fc)
134 {
135         unsigned int hdrlen = 24;
136
137         if (ieee80211_is_data(fc)) {
138                 if (ieee80211_has_a4(fc))
139                         hdrlen = 30;
140                 if (ieee80211_is_data_qos(fc))
141                         hdrlen += IEEE80211_QOS_CTL_LEN;
142                 goto out;
143         }
144
145         if (ieee80211_is_ctl(fc)) {
146                 /*
147                  * ACK and CTS are 10 bytes, all others 16. To see how
148                  * to get this condition consider
149                  *   subtype mask:   0b0000000011110000 (0x00F0)
150                  *   ACK subtype:    0b0000000011010000 (0x00D0)
151                  *   CTS subtype:    0b0000000011000000 (0x00C0)
152                  *   bits that matter:         ^^^      (0x00E0)
153                  *   value of those: 0b0000000011000000 (0x00C0)
154                  */
155                 if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0))
156                         hdrlen = 10;
157                 else
158                         hdrlen = 16;
159         }
160 out:
161         return hdrlen;
162 }
163 EXPORT_SYMBOL(ieee80211_hdrlen);
164
165 unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
166 {
167         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *)skb->data;
168         unsigned int hdrlen;
169
170         if (unlikely(skb->len < 10))
171                 return 0;
172         hdrlen = ieee80211_hdrlen(hdr->frame_control);
173         if (unlikely(hdrlen > skb->len))
174                 return 0;
175         return hdrlen;
176 }
177 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
178
179 int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
180 {
181         int ae = meshhdr->flags & IEEE80211S_FLAGS_AE;
182         /* 7.1.3.5a.2 */
183         switch (ae) {
184         case 0:
185                 return 6;
186         case 1:
187                 return 12;
188         case 2:
189                 return 18;
190         case 3:
191                 return 24;
192         default:
193                 return 6;
194         }
195 }
196
197 void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
198 {
199         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
200
201         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
202         if (tx->extra_frag) {
203                 struct ieee80211_hdr *fhdr;
204                 int i;
205                 for (i = 0; i < tx->num_extra_frag; i++) {
206                         fhdr = (struct ieee80211_hdr *)
207                                 tx->extra_frag[i]->data;
208                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
209                 }
210         }
211 }
212
213 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
214                              int rate, int erp, int short_preamble)
215 {
216         int dur;
217
218         /* calculate duration (in microseconds, rounded up to next higher
219          * integer if it includes a fractional microsecond) to send frame of
220          * len bytes (does not include FCS) at the given rate. Duration will
221          * also include SIFS.
222          *
223          * rate is in 100 kbps, so divident is multiplied by 10 in the
224          * DIV_ROUND_UP() operations.
225          */
226
227         if (local->hw.conf.channel->band == IEEE80211_BAND_5GHZ || erp) {
228                 /*
229                  * OFDM:
230                  *
231                  * N_DBPS = DATARATE x 4
232                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
233                  *      (16 = SIGNAL time, 6 = tail bits)
234                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
235                  *
236                  * T_SYM = 4 usec
237                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
238                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
239                  *      signal ext = 6 usec
240                  */
241                 dur = 16; /* SIFS + signal ext */
242                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
243                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
244                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
245                                         4 * rate); /* T_SYM x N_SYM */
246         } else {
247                 /*
248                  * 802.11b or 802.11g with 802.11b compatibility:
249                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
250                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
251                  *
252                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
253                  * aSIFSTime = 10 usec
254                  * aPreambleLength = 144 usec or 72 usec with short preamble
255                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
256                  */
257                 dur = 10; /* aSIFSTime = 10 usec */
258                 dur += short_preamble ? (72 + 24) : (144 + 48);
259
260                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
261         }
262
263         return dur;
264 }
265
266 /* Exported duration function for driver use */
267 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
268                                         struct ieee80211_vif *vif,
269                                         size_t frame_len,
270                                         struct ieee80211_rate *rate)
271 {
272         struct ieee80211_local *local = hw_to_local(hw);
273         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
274         u16 dur;
275         int erp;
276
277         erp = 0;
278         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
279                 erp = rate->flags & IEEE80211_RATE_ERP_G;
280
281         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate, erp,
282                                        sdata->bss_conf.use_short_preamble);
283
284         return cpu_to_le16(dur);
285 }
286 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
287
288 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
289                               struct ieee80211_vif *vif, size_t frame_len,
290                               const struct ieee80211_tx_info *frame_txctl)
291 {
292         struct ieee80211_local *local = hw_to_local(hw);
293         struct ieee80211_rate *rate;
294         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
295         bool short_preamble;
296         int erp;
297         u16 dur;
298         struct ieee80211_supported_band *sband;
299
300         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
301
302         short_preamble = sdata->bss_conf.use_short_preamble;
303
304         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
305
306         erp = 0;
307         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
308                 erp = rate->flags & IEEE80211_RATE_ERP_G;
309
310         /* CTS duration */
311         dur = ieee80211_frame_duration(local, 10, rate->bitrate,
312                                        erp, short_preamble);
313         /* Data frame duration */
314         dur += ieee80211_frame_duration(local, frame_len, rate->bitrate,
315                                         erp, short_preamble);
316         /* ACK duration */
317         dur += ieee80211_frame_duration(local, 10, rate->bitrate,
318                                         erp, short_preamble);
319
320         return cpu_to_le16(dur);
321 }
322 EXPORT_SYMBOL(ieee80211_rts_duration);
323
324 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
325                                     struct ieee80211_vif *vif,
326                                     size_t frame_len,
327                                     const struct ieee80211_tx_info *frame_txctl)
328 {
329         struct ieee80211_local *local = hw_to_local(hw);
330         struct ieee80211_rate *rate;
331         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
332         bool short_preamble;
333         int erp;
334         u16 dur;
335         struct ieee80211_supported_band *sband;
336
337         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
338
339         short_preamble = sdata->bss_conf.use_short_preamble;
340
341         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
342         erp = 0;
343         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
344                 erp = rate->flags & IEEE80211_RATE_ERP_G;
345
346         /* Data frame duration */
347         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate,
348                                        erp, short_preamble);
349         if (!(frame_txctl->flags & IEEE80211_TX_CTL_NO_ACK)) {
350                 /* ACK duration */
351                 dur += ieee80211_frame_duration(local, 10, rate->bitrate,
352                                                 erp, short_preamble);
353         }
354
355         return cpu_to_le16(dur);
356 }
357 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
358
359 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
360 {
361         struct ieee80211_local *local = hw_to_local(hw);
362
363         if (test_bit(queue, local->queues_pending)) {
364                 set_bit(queue, local->queues_pending_run);
365                 tasklet_schedule(&local->tx_pending_tasklet);
366         } else {
367                 netif_wake_subqueue(local->mdev, queue);
368         }
369 }
370 EXPORT_SYMBOL(ieee80211_wake_queue);
371
372 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
373 {
374         struct ieee80211_local *local = hw_to_local(hw);
375
376         netif_stop_subqueue(local->mdev, queue);
377 }
378 EXPORT_SYMBOL(ieee80211_stop_queue);
379
380 void ieee80211_stop_queues(struct ieee80211_hw *hw)
381 {
382         int i;
383
384         for (i = 0; i < ieee80211_num_queues(hw); i++)
385                 ieee80211_stop_queue(hw, i);
386 }
387 EXPORT_SYMBOL(ieee80211_stop_queues);
388
389 void ieee80211_wake_queues(struct ieee80211_hw *hw)
390 {
391         int i;
392
393         for (i = 0; i < hw->queues + hw->ampdu_queues; i++)
394                 ieee80211_wake_queue(hw, i);
395 }
396 EXPORT_SYMBOL(ieee80211_wake_queues);
397
398 void ieee80211_iterate_active_interfaces(
399         struct ieee80211_hw *hw,
400         void (*iterator)(void *data, u8 *mac,
401                          struct ieee80211_vif *vif),
402         void *data)
403 {
404         struct ieee80211_local *local = hw_to_local(hw);
405         struct ieee80211_sub_if_data *sdata;
406
407         rtnl_lock();
408
409         list_for_each_entry(sdata, &local->interfaces, list) {
410                 switch (sdata->vif.type) {
411                 case IEEE80211_IF_TYPE_INVALID:
412                 case IEEE80211_IF_TYPE_MNTR:
413                 case IEEE80211_IF_TYPE_VLAN:
414                         continue;
415                 case IEEE80211_IF_TYPE_AP:
416                 case IEEE80211_IF_TYPE_STA:
417                 case IEEE80211_IF_TYPE_IBSS:
418                 case IEEE80211_IF_TYPE_WDS:
419                 case IEEE80211_IF_TYPE_MESH_POINT:
420                         break;
421                 }
422                 if (netif_running(sdata->dev))
423                         iterator(data, sdata->dev->dev_addr,
424                                  &sdata->vif);
425         }
426
427         rtnl_unlock();
428 }
429 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
430
431 void ieee80211_iterate_active_interfaces_atomic(
432         struct ieee80211_hw *hw,
433         void (*iterator)(void *data, u8 *mac,
434                          struct ieee80211_vif *vif),
435         void *data)
436 {
437         struct ieee80211_local *local = hw_to_local(hw);
438         struct ieee80211_sub_if_data *sdata;
439
440         rcu_read_lock();
441
442         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
443                 switch (sdata->vif.type) {
444                 case IEEE80211_IF_TYPE_INVALID:
445                 case IEEE80211_IF_TYPE_MNTR:
446                 case IEEE80211_IF_TYPE_VLAN:
447                         continue;
448                 case IEEE80211_IF_TYPE_AP:
449                 case IEEE80211_IF_TYPE_STA:
450                 case IEEE80211_IF_TYPE_IBSS:
451                 case IEEE80211_IF_TYPE_WDS:
452                 case IEEE80211_IF_TYPE_MESH_POINT:
453                         break;
454                 }
455                 if (netif_running(sdata->dev))
456                         iterator(data, sdata->dev->dev_addr,
457                                  &sdata->vif);
458         }
459
460         rcu_read_unlock();
461 }
462 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic);