mac80211: introduce flush operation
[linux-2.6.git] / net / mac80211 / scan.c
1 /*
2  * Scanning implementation
3  *
4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
5  * Copyright 2004, Instant802 Networks, Inc.
6  * Copyright 2005, Devicescape Software, Inc.
7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2 as
12  * published by the Free Software Foundation.
13  */
14
15 #include <linux/wireless.h>
16 #include <linux/if_arp.h>
17 #include <linux/rtnetlink.h>
18 #include <net/mac80211.h>
19
20 #include "ieee80211_i.h"
21 #include "driver-ops.h"
22 #include "mesh.h"
23
24 #define IEEE80211_PROBE_DELAY (HZ / 33)
25 #define IEEE80211_CHANNEL_TIME (HZ / 33)
26 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
27
28 struct ieee80211_bss *
29 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
30                      u8 *ssid, u8 ssid_len)
31 {
32         return (void *)cfg80211_get_bss(local->hw.wiphy,
33                                         ieee80211_get_channel(local->hw.wiphy,
34                                                               freq),
35                                         bssid, ssid, ssid_len,
36                                         0, 0);
37 }
38
39 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
40 {
41         struct ieee80211_bss *bss = (void *)cbss;
42
43         kfree(bss_mesh_id(bss));
44         kfree(bss_mesh_cfg(bss));
45 }
46
47 void ieee80211_rx_bss_put(struct ieee80211_local *local,
48                           struct ieee80211_bss *bss)
49 {
50         cfg80211_put_bss((struct cfg80211_bss *)bss);
51 }
52
53 struct ieee80211_bss *
54 ieee80211_bss_info_update(struct ieee80211_local *local,
55                           struct ieee80211_rx_status *rx_status,
56                           struct ieee80211_mgmt *mgmt,
57                           size_t len,
58                           struct ieee802_11_elems *elems,
59                           struct ieee80211_channel *channel,
60                           bool beacon)
61 {
62         struct ieee80211_bss *bss;
63         int clen;
64         s32 signal = 0;
65
66         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
67                 signal = rx_status->signal * 100;
68         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
69                 signal = (rx_status->signal * 100) / local->hw.max_signal;
70
71         bss = (void *)cfg80211_inform_bss_frame(local->hw.wiphy, channel,
72                                                 mgmt, len, signal, GFP_ATOMIC);
73
74         if (!bss)
75                 return NULL;
76
77         bss->cbss.free_priv = ieee80211_rx_bss_free;
78
79         /* save the ERP value so that it is available at association time */
80         if (elems->erp_info && elems->erp_info_len >= 1) {
81                 bss->erp_value = elems->erp_info[0];
82                 bss->has_erp_value = 1;
83         }
84
85         if (elems->tim) {
86                 struct ieee80211_tim_ie *tim_ie =
87                         (struct ieee80211_tim_ie *)elems->tim;
88                 bss->dtim_period = tim_ie->dtim_period;
89         }
90
91         /* set default value for buggy AP/no TIM element */
92         if (bss->dtim_period == 0)
93                 bss->dtim_period = 1;
94
95         bss->supp_rates_len = 0;
96         if (elems->supp_rates) {
97                 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
98                 if (clen > elems->supp_rates_len)
99                         clen = elems->supp_rates_len;
100                 memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates,
101                        clen);
102                 bss->supp_rates_len += clen;
103         }
104         if (elems->ext_supp_rates) {
105                 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
106                 if (clen > elems->ext_supp_rates_len)
107                         clen = elems->ext_supp_rates_len;
108                 memcpy(&bss->supp_rates[bss->supp_rates_len],
109                        elems->ext_supp_rates, clen);
110                 bss->supp_rates_len += clen;
111         }
112
113         bss->wmm_used = elems->wmm_param || elems->wmm_info;
114
115         if (!beacon)
116                 bss->last_probe_resp = jiffies;
117
118         return bss;
119 }
120
121 ieee80211_rx_result
122 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
123 {
124         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
125         struct ieee80211_mgmt *mgmt;
126         struct ieee80211_bss *bss;
127         u8 *elements;
128         struct ieee80211_channel *channel;
129         size_t baselen;
130         int freq;
131         __le16 fc;
132         bool presp, beacon = false;
133         struct ieee802_11_elems elems;
134
135         if (skb->len < 2)
136                 return RX_DROP_UNUSABLE;
137
138         mgmt = (struct ieee80211_mgmt *) skb->data;
139         fc = mgmt->frame_control;
140
141         if (ieee80211_is_ctl(fc))
142                 return RX_CONTINUE;
143
144         if (skb->len < 24)
145                 return RX_DROP_MONITOR;
146
147         presp = ieee80211_is_probe_resp(fc);
148         if (presp) {
149                 /* ignore ProbeResp to foreign address */
150                 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
151                         return RX_DROP_MONITOR;
152
153                 presp = true;
154                 elements = mgmt->u.probe_resp.variable;
155                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
156         } else {
157                 beacon = ieee80211_is_beacon(fc);
158                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
159                 elements = mgmt->u.beacon.variable;
160         }
161
162         if (!presp && !beacon)
163                 return RX_CONTINUE;
164
165         if (baselen > skb->len)
166                 return RX_DROP_MONITOR;
167
168         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
169
170         if (elems.ds_params && elems.ds_params_len == 1)
171                 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
172         else
173                 freq = rx_status->freq;
174
175         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
176
177         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
178                 return RX_DROP_MONITOR;
179
180         bss = ieee80211_bss_info_update(sdata->local, rx_status,
181                                         mgmt, skb->len, &elems,
182                                         channel, beacon);
183         if (bss)
184                 ieee80211_rx_bss_put(sdata->local, bss);
185
186         dev_kfree_skb(skb);
187         return RX_QUEUED;
188 }
189
190 /* return false if no more work */
191 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
192 {
193         struct cfg80211_scan_request *req = local->scan_req;
194         enum ieee80211_band band;
195         int i, ielen, n_chans;
196
197         do {
198                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
199                         return false;
200
201                 band = local->hw_scan_band;
202                 n_chans = 0;
203                 for (i = 0; i < req->n_channels; i++) {
204                         if (req->channels[i]->band == band) {
205                                 local->hw_scan_req->channels[n_chans] =
206                                                         req->channels[i];
207                                 n_chans++;
208                         }
209                 }
210
211                 local->hw_scan_band++;
212         } while (!n_chans);
213
214         local->hw_scan_req->n_channels = n_chans;
215
216         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
217                                          req->ie, req->ie_len, band);
218         local->hw_scan_req->ie_len = ielen;
219
220         return true;
221 }
222
223 /*
224  * inform AP that we will go to sleep so that it will buffer the frames
225  * while we scan
226  */
227 static void ieee80211_scan_ps_enable(struct ieee80211_sub_if_data *sdata)
228 {
229         struct ieee80211_local *local = sdata->local;
230
231         local->scan_ps_enabled = false;
232
233         /* FIXME: what to do when local->pspolling is true? */
234
235         del_timer_sync(&local->dynamic_ps_timer);
236         cancel_work_sync(&local->dynamic_ps_enable_work);
237
238         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
239                 local->scan_ps_enabled = true;
240                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
241                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
242         }
243
244         if (!(local->scan_ps_enabled) ||
245             !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
246                 /*
247                  * If power save was enabled, no need to send a nullfunc
248                  * frame because AP knows that we are sleeping. But if the
249                  * hardware is creating the nullfunc frame for power save
250                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
251                  * enabled) and power save was enabled, the firmware just
252                  * sent a null frame with power save disabled. So we need
253                  * to send a new nullfunc frame to inform the AP that we
254                  * are again sleeping.
255                  */
256                 ieee80211_send_nullfunc(local, sdata, 1);
257 }
258
259 /* inform AP that we are awake again, unless power save is enabled */
260 static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data *sdata)
261 {
262         struct ieee80211_local *local = sdata->local;
263
264         if (!local->ps_sdata)
265                 ieee80211_send_nullfunc(local, sdata, 0);
266         else if (local->scan_ps_enabled) {
267                 /*
268                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
269                  * will send a nullfunc frame with the powersave bit set
270                  * even though the AP already knows that we are sleeping.
271                  * This could be avoided by sending a null frame with power
272                  * save bit disabled before enabling the power save, but
273                  * this doesn't gain anything.
274                  *
275                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
276                  * to send a nullfunc frame because AP already knows that
277                  * we are sleeping, let's just enable power save mode in
278                  * hardware.
279                  */
280                 local->hw.conf.flags |= IEEE80211_CONF_PS;
281                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
282         } else if (local->hw.conf.dynamic_ps_timeout > 0) {
283                 /*
284                  * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
285                  * had been running before leaving the operating channel,
286                  * restart the timer now and send a nullfunc frame to inform
287                  * the AP that we are awake.
288                  */
289                 ieee80211_send_nullfunc(local, sdata, 0);
290                 mod_timer(&local->dynamic_ps_timer, jiffies +
291                           msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
292         }
293 }
294
295 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
296 {
297         struct ieee80211_local *local = hw_to_local(hw);
298         struct ieee80211_sub_if_data *sdata;
299         bool was_hw_scan;
300
301         mutex_lock(&local->scan_mtx);
302
303         /*
304          * It's ok to abort a not-yet-running scan (that
305          * we have one at all will be verified by checking
306          * local->scan_req next), but not to complete it
307          * successfully.
308          */
309         if (WARN_ON(!local->scanning && !aborted))
310                 aborted = true;
311
312         if (WARN_ON(!local->scan_req)) {
313                 mutex_unlock(&local->scan_mtx);
314                 return;
315         }
316
317         was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
318         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
319                 ieee80211_queue_delayed_work(&local->hw,
320                                              &local->scan_work, 0);
321                 mutex_unlock(&local->scan_mtx);
322                 return;
323         }
324
325         kfree(local->hw_scan_req);
326         local->hw_scan_req = NULL;
327
328         if (local->scan_req != local->int_scan_req)
329                 cfg80211_scan_done(local->scan_req, aborted);
330         local->scan_req = NULL;
331         local->scan_sdata = NULL;
332
333         local->scanning = 0;
334         local->scan_channel = NULL;
335
336         /* we only have to protect scan_req and hw/sw scan */
337         mutex_unlock(&local->scan_mtx);
338
339         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
340         if (was_hw_scan)
341                 goto done;
342
343         ieee80211_configure_filter(local);
344
345         drv_sw_scan_complete(local);
346
347         mutex_lock(&local->iflist_mtx);
348         list_for_each_entry(sdata, &local->interfaces, list) {
349                 if (!ieee80211_sdata_running(sdata))
350                         continue;
351
352                 /* Tell AP we're back */
353                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
354                         if (sdata->u.mgd.associated) {
355                                 ieee80211_scan_ps_disable(sdata);
356                                 netif_wake_queue(sdata->dev);
357                         }
358                 } else
359                         netif_wake_queue(sdata->dev);
360
361                 /* re-enable beaconing */
362                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
363                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
364                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
365                         ieee80211_bss_info_change_notify(
366                                 sdata, BSS_CHANGED_BEACON_ENABLED);
367         }
368         mutex_unlock(&local->iflist_mtx);
369
370  done:
371         ieee80211_recalc_idle(local);
372         ieee80211_mlme_notify_scan_completed(local);
373         ieee80211_ibss_notify_scan_completed(local);
374         ieee80211_mesh_notify_scan_completed(local);
375 }
376 EXPORT_SYMBOL(ieee80211_scan_completed);
377
378 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
379 {
380         struct ieee80211_sub_if_data *sdata;
381
382         /*
383          * Hardware/driver doesn't support hw_scan, so use software
384          * scanning instead. First send a nullfunc frame with power save
385          * bit on so that AP will buffer the frames for us while we are not
386          * listening, then send probe requests to each channel and wait for
387          * the responses. After all channels are scanned, tune back to the
388          * original channel and send a nullfunc frame with power save bit
389          * off to trigger the AP to send us all the buffered frames.
390          *
391          * Note that while local->sw_scanning is true everything else but
392          * nullfunc frames and probe requests will be dropped in
393          * ieee80211_tx_h_check_assoc().
394          */
395         drv_sw_scan_start(local);
396
397         mutex_lock(&local->iflist_mtx);
398         list_for_each_entry(sdata, &local->interfaces, list) {
399                 if (!ieee80211_sdata_running(sdata))
400                         continue;
401
402                 /* disable beaconing */
403                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
404                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
405                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
406                         ieee80211_bss_info_change_notify(
407                                 sdata, BSS_CHANGED_BEACON_ENABLED);
408
409                 /*
410                  * only handle non-STA interfaces here, STA interfaces
411                  * are handled in the scan state machine
412                  */
413                 if (sdata->vif.type != NL80211_IFTYPE_STATION)
414                         netif_stop_queue(sdata->dev);
415         }
416         mutex_unlock(&local->iflist_mtx);
417
418         local->next_scan_state = SCAN_DECISION;
419         local->scan_channel_idx = 0;
420
421         drv_flush(local, false);
422
423         ieee80211_configure_filter(local);
424
425         ieee80211_queue_delayed_work(&local->hw,
426                                      &local->scan_work,
427                                      IEEE80211_CHANNEL_TIME);
428
429         return 0;
430 }
431
432
433 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
434                                   struct cfg80211_scan_request *req)
435 {
436         struct ieee80211_local *local = sdata->local;
437         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
438         int rc;
439
440         if (local->scan_req)
441                 return -EBUSY;
442
443         if (local->ops->hw_scan) {
444                 u8 *ies;
445
446                 local->hw_scan_req = kmalloc(
447                                 sizeof(*local->hw_scan_req) +
448                                 req->n_channels * sizeof(req->channels[0]) +
449                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
450                                 req->ie_len, GFP_KERNEL);
451                 if (!local->hw_scan_req)
452                         return -ENOMEM;
453
454                 local->hw_scan_req->ssids = req->ssids;
455                 local->hw_scan_req->n_ssids = req->n_ssids;
456                 ies = (u8 *)local->hw_scan_req +
457                         sizeof(*local->hw_scan_req) +
458                         req->n_channels * sizeof(req->channels[0]);
459                 local->hw_scan_req->ie = ies;
460
461                 local->hw_scan_band = 0;
462         }
463
464         local->scan_req = req;
465         local->scan_sdata = sdata;
466
467         if (req != local->int_scan_req &&
468             sdata->vif.type == NL80211_IFTYPE_STATION &&
469             !list_empty(&ifmgd->work_list)) {
470                 /* actually wait for the work it's doing to finish/time out */
471                 set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
472                 return 0;
473         }
474
475         if (local->ops->hw_scan)
476                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
477         else
478                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
479         /*
480          * Kicking off the scan need not be protected,
481          * only the scan variable stuff, since now
482          * local->scan_req is assigned and other callers
483          * will abort their scan attempts.
484          *
485          * This avoids getting a scan_mtx -> iflist_mtx
486          * dependency, so that the scan completed calls
487          * have more locking freedom.
488          */
489
490         ieee80211_recalc_idle(local);
491         mutex_unlock(&local->scan_mtx);
492
493         if (local->ops->hw_scan) {
494                 WARN_ON(!ieee80211_prep_hw_scan(local));
495                 rc = drv_hw_scan(local, local->hw_scan_req);
496         } else
497                 rc = ieee80211_start_sw_scan(local);
498
499         mutex_lock(&local->scan_mtx);
500
501         if (rc) {
502                 kfree(local->hw_scan_req);
503                 local->hw_scan_req = NULL;
504                 local->scanning = 0;
505
506                 ieee80211_recalc_idle(local);
507
508                 local->scan_req = NULL;
509                 local->scan_sdata = NULL;
510         }
511
512         return rc;
513 }
514
515 static int ieee80211_scan_state_decision(struct ieee80211_local *local,
516                                          unsigned long *next_delay)
517 {
518         bool associated = false;
519         struct ieee80211_sub_if_data *sdata;
520
521         /* if no more bands/channels left, complete scan and advance to the idle state */
522         if (local->scan_channel_idx >= local->scan_req->n_channels) {
523                 ieee80211_scan_completed(&local->hw, false);
524                 return 1;
525         }
526
527         /* check if at least one STA interface is associated */
528         mutex_lock(&local->iflist_mtx);
529         list_for_each_entry(sdata, &local->interfaces, list) {
530                 if (!ieee80211_sdata_running(sdata))
531                         continue;
532
533                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
534                         if (sdata->u.mgd.associated) {
535                                 associated = true;
536                                 break;
537                         }
538                 }
539         }
540         mutex_unlock(&local->iflist_mtx);
541
542         if (local->scan_channel) {
543                 /*
544                  * we're currently scanning a different channel, let's
545                  * switch back to the operating channel now if at least
546                  * one interface is associated. Otherwise just scan the
547                  * next channel
548                  */
549                 if (associated)
550                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
551                 else
552                         local->next_scan_state = SCAN_SET_CHANNEL;
553         } else {
554                 /*
555                  * we're on the operating channel currently, let's
556                  * leave that channel now to scan another one
557                  */
558                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
559         }
560
561         *next_delay = 0;
562         return 0;
563 }
564
565 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
566                                                     unsigned long *next_delay)
567 {
568         struct ieee80211_sub_if_data *sdata;
569
570         /*
571          * notify the AP about us leaving the channel and stop all STA interfaces
572          */
573         mutex_lock(&local->iflist_mtx);
574         list_for_each_entry(sdata, &local->interfaces, list) {
575                 if (!ieee80211_sdata_running(sdata))
576                         continue;
577
578                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
579                         netif_stop_queue(sdata->dev);
580                         if (sdata->u.mgd.associated)
581                                 ieee80211_scan_ps_enable(sdata);
582                 }
583         }
584         mutex_unlock(&local->iflist_mtx);
585
586         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
587
588         /*
589          * What if the nullfunc frames didn't arrive?
590          */
591         drv_flush(local, false);
592         if (local->ops->flush)
593                 *next_delay = 0;
594         else
595                 *next_delay = HZ / 10;
596
597         /* advance to the next channel to be scanned */
598         local->next_scan_state = SCAN_SET_CHANNEL;
599 }
600
601 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
602                                                     unsigned long *next_delay)
603 {
604         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
605
606         /* switch back to the operating channel */
607         local->scan_channel = NULL;
608         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
609
610         /*
611          * notify the AP about us being back and restart all STA interfaces
612          */
613         mutex_lock(&local->iflist_mtx);
614         list_for_each_entry(sdata, &local->interfaces, list) {
615                 if (!ieee80211_sdata_running(sdata))
616                         continue;
617
618                 /* Tell AP we're back */
619                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
620                         if (sdata->u.mgd.associated)
621                                 ieee80211_scan_ps_disable(sdata);
622                         netif_wake_queue(sdata->dev);
623                 }
624         }
625         mutex_unlock(&local->iflist_mtx);
626
627         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
628
629         *next_delay = HZ / 5;
630         local->next_scan_state = SCAN_DECISION;
631 }
632
633 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
634                                              unsigned long *next_delay)
635 {
636         int skip;
637         struct ieee80211_channel *chan;
638
639         skip = 0;
640         chan = local->scan_req->channels[local->scan_channel_idx];
641
642         local->scan_channel = chan;
643         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
644                 skip = 1;
645
646         /* advance state machine to next channel/band */
647         local->scan_channel_idx++;
648
649         if (skip) {
650                 /* if we skip this channel return to the decision state */
651                 local->next_scan_state = SCAN_DECISION;
652                 return;
653         }
654
655         /*
656          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
657          * (which unfortunately doesn't say _why_ step a) is done,
658          * but it waits for the probe delay or until a frame is
659          * received - and the received frame would update the NAV).
660          * For now, we do not support waiting until a frame is
661          * received.
662          *
663          * In any case, it is not necessary for a passive scan.
664          */
665         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
666             !local->scan_req->n_ssids) {
667                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
668                 local->next_scan_state = SCAN_DECISION;
669                 return;
670         }
671
672         /* active scan, send probes */
673         *next_delay = IEEE80211_PROBE_DELAY;
674         local->next_scan_state = SCAN_SEND_PROBE;
675 }
676
677 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
678                                             unsigned long *next_delay)
679 {
680         int i;
681         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
682
683         for (i = 0; i < local->scan_req->n_ssids; i++)
684                 ieee80211_send_probe_req(
685                         sdata, NULL,
686                         local->scan_req->ssids[i].ssid,
687                         local->scan_req->ssids[i].ssid_len,
688                         local->scan_req->ie, local->scan_req->ie_len);
689
690         /*
691          * After sending probe requests, wait for probe responses
692          * on the channel.
693          */
694         *next_delay = IEEE80211_CHANNEL_TIME;
695         local->next_scan_state = SCAN_DECISION;
696 }
697
698 void ieee80211_scan_work(struct work_struct *work)
699 {
700         struct ieee80211_local *local =
701                 container_of(work, struct ieee80211_local, scan_work.work);
702         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
703         unsigned long next_delay = 0;
704
705         mutex_lock(&local->scan_mtx);
706         if (!sdata || !local->scan_req) {
707                 mutex_unlock(&local->scan_mtx);
708                 return;
709         }
710
711         if (local->hw_scan_req) {
712                 int rc = drv_hw_scan(local, local->hw_scan_req);
713                 mutex_unlock(&local->scan_mtx);
714                 if (rc)
715                         ieee80211_scan_completed(&local->hw, true);
716                 return;
717         }
718
719         if (local->scan_req && !local->scanning) {
720                 struct cfg80211_scan_request *req = local->scan_req;
721                 int rc;
722
723                 local->scan_req = NULL;
724                 local->scan_sdata = NULL;
725
726                 rc = __ieee80211_start_scan(sdata, req);
727                 mutex_unlock(&local->scan_mtx);
728
729                 if (rc)
730                         ieee80211_scan_completed(&local->hw, true);
731                 return;
732         }
733
734         mutex_unlock(&local->scan_mtx);
735
736         /*
737          * Avoid re-scheduling when the sdata is going away.
738          */
739         if (!ieee80211_sdata_running(sdata)) {
740                 ieee80211_scan_completed(&local->hw, true);
741                 return;
742         }
743
744         /*
745          * as long as no delay is required advance immediately
746          * without scheduling a new work
747          */
748         do {
749                 switch (local->next_scan_state) {
750                 case SCAN_DECISION:
751                         if (ieee80211_scan_state_decision(local, &next_delay))
752                                 return;
753                         break;
754                 case SCAN_SET_CHANNEL:
755                         ieee80211_scan_state_set_channel(local, &next_delay);
756                         break;
757                 case SCAN_SEND_PROBE:
758                         ieee80211_scan_state_send_probe(local, &next_delay);
759                         break;
760                 case SCAN_LEAVE_OPER_CHANNEL:
761                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
762                         break;
763                 case SCAN_ENTER_OPER_CHANNEL:
764                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
765                         break;
766                 }
767         } while (next_delay == 0);
768
769         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
770 }
771
772 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
773                            struct cfg80211_scan_request *req)
774 {
775         int res;
776
777         mutex_lock(&sdata->local->scan_mtx);
778         res = __ieee80211_start_scan(sdata, req);
779         mutex_unlock(&sdata->local->scan_mtx);
780
781         return res;
782 }
783
784 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
785                                     const u8 *ssid, u8 ssid_len)
786 {
787         struct ieee80211_local *local = sdata->local;
788         int ret = -EBUSY;
789
790         mutex_lock(&local->scan_mtx);
791
792         /* busy scanning */
793         if (local->scan_req)
794                 goto unlock;
795
796         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
797         local->int_scan_req->ssids[0].ssid_len = ssid_len;
798
799         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
800  unlock:
801         mutex_unlock(&local->scan_mtx);
802         return ret;
803 }
804
805 void ieee80211_scan_cancel(struct ieee80211_local *local)
806 {
807         bool abortscan;
808
809         cancel_delayed_work_sync(&local->scan_work);
810
811         /*
812          * Only call this function when a scan can't be
813          * queued -- mostly at suspend under RTNL.
814          */
815         mutex_lock(&local->scan_mtx);
816         abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
817                     (!local->scanning && local->scan_req);
818         mutex_unlock(&local->scan_mtx);
819
820         if (abortscan)
821                 ieee80211_scan_completed(&local->hw, true);
822 }