Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
[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 "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[] =
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[] =
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         u16 fc;
49
50          /* drop ACK/CTS frames and incorrect hdr len (ctrl) */
51         if (len < 16)
52                 return NULL;
53
54         fc = le16_to_cpu(hdr->frame_control);
55
56         switch (fc & IEEE80211_FCTL_FTYPE) {
57         case IEEE80211_FTYPE_DATA:
58                 if (len < 24) /* drop incorrect hdr len (data) */
59                         return NULL;
60                 switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
61                 case IEEE80211_FCTL_TODS:
62                         return hdr->addr1;
63                 case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
64                         return NULL;
65                 case IEEE80211_FCTL_FROMDS:
66                         return hdr->addr2;
67                 case 0:
68                         return hdr->addr3;
69                 }
70                 break;
71         case IEEE80211_FTYPE_MGMT:
72                 if (len < 24) /* drop incorrect hdr len (mgmt) */
73                         return NULL;
74                 return hdr->addr3;
75         case IEEE80211_FTYPE_CTL:
76                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
77                         return hdr->addr1;
78                 else if ((fc & IEEE80211_FCTL_STYPE) ==
79                                                 IEEE80211_STYPE_BACK_REQ) {
80                         switch (type) {
81                         case IEEE80211_IF_TYPE_STA:
82                                 return hdr->addr2;
83                         case IEEE80211_IF_TYPE_AP:
84                         case IEEE80211_IF_TYPE_VLAN:
85                                 return hdr->addr1;
86                         default:
87                                 return NULL;
88                         }
89                 }
90                 else
91                         return NULL;
92         }
93
94         return NULL;
95 }
96
97 int ieee80211_get_hdrlen(u16 fc)
98 {
99         int hdrlen = 24;
100
101         switch (fc & IEEE80211_FCTL_FTYPE) {
102         case IEEE80211_FTYPE_DATA:
103                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
104                         hdrlen = 30; /* Addr4 */
105                 /*
106                  * The QoS Control field is two bytes and its presence is
107                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
108                  * hdrlen if that bit is set.
109                  * This works by masking out the bit and shifting it to
110                  * bit position 1 so the result has the value 0 or 2.
111                  */
112                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
113                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
114                 break;
115         case IEEE80211_FTYPE_CTL:
116                 /*
117                  * ACK and CTS are 10 bytes, all others 16. To see how
118                  * to get this condition consider
119                  *   subtype mask:   0b0000000011110000 (0x00F0)
120                  *   ACK subtype:    0b0000000011010000 (0x00D0)
121                  *   CTS subtype:    0b0000000011000000 (0x00C0)
122                  *   bits that matter:         ^^^      (0x00E0)
123                  *   value of those: 0b0000000011000000 (0x00C0)
124                  */
125                 if ((fc & 0xE0) == 0xC0)
126                         hdrlen = 10;
127                 else
128                         hdrlen = 16;
129                 break;
130         }
131
132         return hdrlen;
133 }
134 EXPORT_SYMBOL(ieee80211_get_hdrlen);
135
136 int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
137 {
138         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
139         int hdrlen;
140
141         if (unlikely(skb->len < 10))
142                 return 0;
143         hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
144         if (unlikely(hdrlen > skb->len))
145                 return 0;
146         return hdrlen;
147 }
148 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
149
150 int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
151 {
152         int ae = meshhdr->flags & IEEE80211S_FLAGS_AE;
153         /* 7.1.3.5a.2 */
154         switch (ae) {
155         case 0:
156                 return 5;
157         case 1:
158                 return 11;
159         case 2:
160                 return 17;
161         case 3:
162                 return 23;
163         default:
164                 return 5;
165         }
166 }
167
168 void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
169 {
170         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
171
172         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
173         if (tx->extra_frag) {
174                 struct ieee80211_hdr *fhdr;
175                 int i;
176                 for (i = 0; i < tx->num_extra_frag; i++) {
177                         fhdr = (struct ieee80211_hdr *)
178                                 tx->extra_frag[i]->data;
179                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
180                 }
181         }
182 }
183
184 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
185                              int rate, int erp, int short_preamble)
186 {
187         int dur;
188
189         /* calculate duration (in microseconds, rounded up to next higher
190          * integer if it includes a fractional microsecond) to send frame of
191          * len bytes (does not include FCS) at the given rate. Duration will
192          * also include SIFS.
193          *
194          * rate is in 100 kbps, so divident is multiplied by 10 in the
195          * DIV_ROUND_UP() operations.
196          */
197
198         if (local->hw.conf.channel->band == IEEE80211_BAND_5GHZ || erp) {
199                 /*
200                  * OFDM:
201                  *
202                  * N_DBPS = DATARATE x 4
203                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
204                  *      (16 = SIGNAL time, 6 = tail bits)
205                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
206                  *
207                  * T_SYM = 4 usec
208                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
209                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
210                  *      signal ext = 6 usec
211                  */
212                 dur = 16; /* SIFS + signal ext */
213                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
214                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
215                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
216                                         4 * rate); /* T_SYM x N_SYM */
217         } else {
218                 /*
219                  * 802.11b or 802.11g with 802.11b compatibility:
220                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
221                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
222                  *
223                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
224                  * aSIFSTime = 10 usec
225                  * aPreambleLength = 144 usec or 72 usec with short preamble
226                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
227                  */
228                 dur = 10; /* aSIFSTime = 10 usec */
229                 dur += short_preamble ? (72 + 24) : (144 + 48);
230
231                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
232         }
233
234         return dur;
235 }
236
237 /* Exported duration function for driver use */
238 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
239                                         struct ieee80211_vif *vif,
240                                         size_t frame_len,
241                                         struct ieee80211_rate *rate)
242 {
243         struct ieee80211_local *local = hw_to_local(hw);
244         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
245         u16 dur;
246         int erp;
247
248         erp = 0;
249         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
250                 erp = rate->flags & IEEE80211_RATE_ERP_G;
251
252         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate, erp,
253                                        sdata->bss_conf.use_short_preamble);
254
255         return cpu_to_le16(dur);
256 }
257 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
258
259 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
260                               struct ieee80211_vif *vif, size_t frame_len,
261                               const struct ieee80211_tx_control *frame_txctl)
262 {
263         struct ieee80211_local *local = hw_to_local(hw);
264         struct ieee80211_rate *rate;
265         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
266         bool short_preamble;
267         int erp;
268         u16 dur;
269
270         short_preamble = sdata->bss_conf.use_short_preamble;
271
272         rate = frame_txctl->rts_cts_rate;
273
274         erp = 0;
275         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
276                 erp = rate->flags & IEEE80211_RATE_ERP_G;
277
278         /* CTS duration */
279         dur = ieee80211_frame_duration(local, 10, rate->bitrate,
280                                        erp, short_preamble);
281         /* Data frame duration */
282         dur += ieee80211_frame_duration(local, frame_len, rate->bitrate,
283                                         erp, short_preamble);
284         /* ACK duration */
285         dur += ieee80211_frame_duration(local, 10, rate->bitrate,
286                                         erp, short_preamble);
287
288         return cpu_to_le16(dur);
289 }
290 EXPORT_SYMBOL(ieee80211_rts_duration);
291
292 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
293                                     struct ieee80211_vif *vif,
294                                     size_t frame_len,
295                                     const struct ieee80211_tx_control *frame_txctl)
296 {
297         struct ieee80211_local *local = hw_to_local(hw);
298         struct ieee80211_rate *rate;
299         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
300         bool short_preamble;
301         int erp;
302         u16 dur;
303
304         short_preamble = sdata->bss_conf.use_short_preamble;
305
306         rate = frame_txctl->rts_cts_rate;
307         erp = 0;
308         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
309                 erp = rate->flags & IEEE80211_RATE_ERP_G;
310
311         /* Data frame duration */
312         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate,
313                                        erp, short_preamble);
314         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
315                 /* ACK duration */
316                 dur += ieee80211_frame_duration(local, 10, rate->bitrate,
317                                                 erp, short_preamble);
318         }
319
320         return cpu_to_le16(dur);
321 }
322 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
323
324 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
325 {
326         struct ieee80211_local *local = hw_to_local(hw);
327
328         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
329                                &local->state[queue])) {
330                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
331                              &local->state[queue]))
332                         tasklet_schedule(&local->tx_pending_tasklet);
333                 else
334                         if (!ieee80211_qdisc_installed(local->mdev)) {
335                                 if (queue == 0)
336                                         netif_wake_queue(local->mdev);
337                         } else
338                                 __netif_schedule(local->mdev);
339         }
340 }
341 EXPORT_SYMBOL(ieee80211_wake_queue);
342
343 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
344 {
345         struct ieee80211_local *local = hw_to_local(hw);
346
347         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
348                 netif_stop_queue(local->mdev);
349         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
350 }
351 EXPORT_SYMBOL(ieee80211_stop_queue);
352
353 void ieee80211_start_queues(struct ieee80211_hw *hw)
354 {
355         struct ieee80211_local *local = hw_to_local(hw);
356         int i;
357
358         for (i = 0; i < local->hw.queues; i++)
359                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
360         if (!ieee80211_qdisc_installed(local->mdev))
361                 netif_start_queue(local->mdev);
362 }
363 EXPORT_SYMBOL(ieee80211_start_queues);
364
365 void ieee80211_stop_queues(struct ieee80211_hw *hw)
366 {
367         int i;
368
369         for (i = 0; i < hw->queues; i++)
370                 ieee80211_stop_queue(hw, i);
371 }
372 EXPORT_SYMBOL(ieee80211_stop_queues);
373
374 void ieee80211_wake_queues(struct ieee80211_hw *hw)
375 {
376         int i;
377
378         for (i = 0; i < hw->queues; i++)
379                 ieee80211_wake_queue(hw, i);
380 }
381 EXPORT_SYMBOL(ieee80211_wake_queues);
382
383 void ieee80211_iterate_active_interfaces(
384         struct ieee80211_hw *hw,
385         void (*iterator)(void *data, u8 *mac,
386                          struct ieee80211_vif *vif),
387         void *data)
388 {
389         struct ieee80211_local *local = hw_to_local(hw);
390         struct ieee80211_sub_if_data *sdata;
391
392         rcu_read_lock();
393
394         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
395                 switch (sdata->vif.type) {
396                 case IEEE80211_IF_TYPE_INVALID:
397                 case IEEE80211_IF_TYPE_MNTR:
398                 case IEEE80211_IF_TYPE_VLAN:
399                         continue;
400                 case IEEE80211_IF_TYPE_AP:
401                 case IEEE80211_IF_TYPE_STA:
402                 case IEEE80211_IF_TYPE_IBSS:
403                 case IEEE80211_IF_TYPE_WDS:
404                 case IEEE80211_IF_TYPE_MESH_POINT:
405                         break;
406                 }
407                 if (sdata->dev == local->mdev)
408                         continue;
409                 if (netif_running(sdata->dev))
410                         iterator(data, sdata->dev->dev_addr,
411                                  &sdata->vif);
412         }
413
414         rcu_read_unlock();
415 }
416 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);