cfg80211: validate scan channels
[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->dev->dev_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         bool ps = false;
231
232         /* FIXME: what to do when local->pspolling is true? */
233
234         del_timer_sync(&local->dynamic_ps_timer);
235         cancel_work_sync(&local->dynamic_ps_enable_work);
236
237         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
238                 ps = true;
239                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
240                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
241         }
242
243         if (!ps || !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
244                 /*
245                  * If power save was enabled, no need to send a nullfunc
246                  * frame because AP knows that we are sleeping. But if the
247                  * hardware is creating the nullfunc frame for power save
248                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
249                  * enabled) and power save was enabled, the firmware just
250                  * sent a null frame with power save disabled. So we need
251                  * to send a new nullfunc frame to inform the AP that we
252                  * are again sleeping.
253                  */
254                 ieee80211_send_nullfunc(local, sdata, 1);
255 }
256
257 /* inform AP that we are awake again, unless power save is enabled */
258 static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data *sdata)
259 {
260         struct ieee80211_local *local = sdata->local;
261
262         if (!local->ps_sdata)
263                 ieee80211_send_nullfunc(local, sdata, 0);
264         else {
265                 /*
266                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
267                  * will send a nullfunc frame with the powersave bit set
268                  * even though the AP already knows that we are sleeping.
269                  * This could be avoided by sending a null frame with power
270                  * save bit disabled before enabling the power save, but
271                  * this doesn't gain anything.
272                  *
273                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
274                  * to send a nullfunc frame because AP already knows that
275                  * we are sleeping, let's just enable power save mode in
276                  * hardware.
277                  */
278                 local->hw.conf.flags |= IEEE80211_CONF_PS;
279                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
280         }
281 }
282
283 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
284 {
285         struct ieee80211_local *local = hw_to_local(hw);
286         struct ieee80211_sub_if_data *sdata;
287         bool was_hw_scan;
288
289         mutex_lock(&local->scan_mtx);
290
291         /*
292          * It's ok to abort a not-yet-running scan (that
293          * we have one at all will be verified by checking
294          * local->scan_req next), but not to complete it
295          * successfully.
296          */
297         if (WARN_ON(!local->scanning && !aborted))
298                 aborted = true;
299
300         if (WARN_ON(!local->scan_req)) {
301                 mutex_unlock(&local->scan_mtx);
302                 return;
303         }
304
305         was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
306         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
307                 ieee80211_queue_delayed_work(&local->hw,
308                                              &local->scan_work, 0);
309                 mutex_unlock(&local->scan_mtx);
310                 return;
311         }
312
313         kfree(local->hw_scan_req);
314         local->hw_scan_req = NULL;
315
316         if (local->scan_req != local->int_scan_req)
317                 cfg80211_scan_done(local->scan_req, aborted);
318         local->scan_req = NULL;
319         local->scan_sdata = NULL;
320
321         local->scanning = 0;
322         local->scan_channel = NULL;
323
324         /* we only have to protect scan_req and hw/sw scan */
325         mutex_unlock(&local->scan_mtx);
326
327         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
328         if (was_hw_scan)
329                 goto done;
330
331         ieee80211_configure_filter(local);
332
333         drv_sw_scan_complete(local);
334
335         mutex_lock(&local->iflist_mtx);
336         list_for_each_entry(sdata, &local->interfaces, list) {
337                 if (!netif_running(sdata->dev))
338                         continue;
339
340                 /* Tell AP we're back */
341                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
342                         if (sdata->u.mgd.associated) {
343                                 ieee80211_scan_ps_disable(sdata);
344                                 netif_wake_queue(sdata->dev);
345                         }
346                 } else
347                         netif_wake_queue(sdata->dev);
348
349                 /* re-enable beaconing */
350                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
351                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
352                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
353                         ieee80211_bss_info_change_notify(
354                                 sdata, BSS_CHANGED_BEACON_ENABLED);
355         }
356         mutex_unlock(&local->iflist_mtx);
357
358  done:
359         ieee80211_recalc_idle(local);
360         ieee80211_mlme_notify_scan_completed(local);
361         ieee80211_ibss_notify_scan_completed(local);
362         ieee80211_mesh_notify_scan_completed(local);
363 }
364 EXPORT_SYMBOL(ieee80211_scan_completed);
365
366 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
367 {
368         struct ieee80211_sub_if_data *sdata;
369
370         /*
371          * Hardware/driver doesn't support hw_scan, so use software
372          * scanning instead. First send a nullfunc frame with power save
373          * bit on so that AP will buffer the frames for us while we are not
374          * listening, then send probe requests to each channel and wait for
375          * the responses. After all channels are scanned, tune back to the
376          * original channel and send a nullfunc frame with power save bit
377          * off to trigger the AP to send us all the buffered frames.
378          *
379          * Note that while local->sw_scanning is true everything else but
380          * nullfunc frames and probe requests will be dropped in
381          * ieee80211_tx_h_check_assoc().
382          */
383         drv_sw_scan_start(local);
384
385         mutex_lock(&local->iflist_mtx);
386         list_for_each_entry(sdata, &local->interfaces, list) {
387                 if (!netif_running(sdata->dev))
388                         continue;
389
390                 /* disable beaconing */
391                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
392                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
393                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
394                         ieee80211_bss_info_change_notify(
395                                 sdata, BSS_CHANGED_BEACON_ENABLED);
396
397                 /*
398                  * only handle non-STA interfaces here, STA interfaces
399                  * are handled in the scan state machine
400                  */
401                 if (sdata->vif.type != NL80211_IFTYPE_STATION)
402                         netif_stop_queue(sdata->dev);
403         }
404         mutex_unlock(&local->iflist_mtx);
405
406         local->next_scan_state = SCAN_DECISION;
407         local->scan_channel_idx = 0;
408
409         ieee80211_configure_filter(local);
410
411         /* TODO: start scan as soon as all nullfunc frames are ACKed */
412         ieee80211_queue_delayed_work(&local->hw,
413                                      &local->scan_work,
414                                      IEEE80211_CHANNEL_TIME);
415
416         return 0;
417 }
418
419
420 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
421                                   struct cfg80211_scan_request *req)
422 {
423         struct ieee80211_local *local = sdata->local;
424         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
425         int rc;
426
427         if (local->scan_req)
428                 return -EBUSY;
429
430         if (local->ops->hw_scan) {
431                 u8 *ies;
432
433                 local->hw_scan_req = kmalloc(
434                                 sizeof(*local->hw_scan_req) +
435                                 req->n_channels * sizeof(req->channels[0]) +
436                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
437                                 req->ie_len, GFP_KERNEL);
438                 if (!local->hw_scan_req)
439                         return -ENOMEM;
440
441                 local->hw_scan_req->ssids = req->ssids;
442                 local->hw_scan_req->n_ssids = req->n_ssids;
443                 ies = (u8 *)local->hw_scan_req +
444                         sizeof(*local->hw_scan_req) +
445                         req->n_channels * sizeof(req->channels[0]);
446                 local->hw_scan_req->ie = ies;
447
448                 local->hw_scan_band = 0;
449         }
450
451         local->scan_req = req;
452         local->scan_sdata = sdata;
453
454         if (req != local->int_scan_req &&
455             sdata->vif.type == NL80211_IFTYPE_STATION &&
456             !list_empty(&ifmgd->work_list)) {
457                 /* actually wait for the work it's doing to finish/time out */
458                 set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
459                 return 0;
460         }
461
462         if (local->ops->hw_scan)
463                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
464         else
465                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
466         /*
467          * Kicking off the scan need not be protected,
468          * only the scan variable stuff, since now
469          * local->scan_req is assigned and other callers
470          * will abort their scan attempts.
471          *
472          * This avoids getting a scan_mtx -> iflist_mtx
473          * dependency, so that the scan completed calls
474          * have more locking freedom.
475          */
476
477         ieee80211_recalc_idle(local);
478         mutex_unlock(&local->scan_mtx);
479
480         if (local->ops->hw_scan) {
481                 WARN_ON(!ieee80211_prep_hw_scan(local));
482                 rc = drv_hw_scan(local, local->hw_scan_req);
483         } else
484                 rc = ieee80211_start_sw_scan(local);
485
486         mutex_lock(&local->scan_mtx);
487
488         if (rc) {
489                 kfree(local->hw_scan_req);
490                 local->hw_scan_req = NULL;
491                 local->scanning = 0;
492
493                 ieee80211_recalc_idle(local);
494
495                 local->scan_req = NULL;
496                 local->scan_sdata = NULL;
497         }
498
499         return rc;
500 }
501
502 static int ieee80211_scan_state_decision(struct ieee80211_local *local,
503                                          unsigned long *next_delay)
504 {
505         bool associated = false;
506         struct ieee80211_sub_if_data *sdata;
507
508         /* if no more bands/channels left, complete scan and advance to the idle state */
509         if (local->scan_channel_idx >= local->scan_req->n_channels) {
510                 ieee80211_scan_completed(&local->hw, false);
511                 return 1;
512         }
513
514         /* check if at least one STA interface is associated */
515         mutex_lock(&local->iflist_mtx);
516         list_for_each_entry(sdata, &local->interfaces, list) {
517                 if (!netif_running(sdata->dev))
518                         continue;
519
520                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
521                         if (sdata->u.mgd.associated) {
522                                 associated = true;
523                                 break;
524                         }
525                 }
526         }
527         mutex_unlock(&local->iflist_mtx);
528
529         if (local->scan_channel) {
530                 /*
531                  * we're currently scanning a different channel, let's
532                  * switch back to the operating channel now if at least
533                  * one interface is associated. Otherwise just scan the
534                  * next channel
535                  */
536                 if (associated)
537                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
538                 else
539                         local->next_scan_state = SCAN_SET_CHANNEL;
540         } else {
541                 /*
542                  * we're on the operating channel currently, let's
543                  * leave that channel now to scan another one
544                  */
545                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
546         }
547
548         *next_delay = 0;
549         return 0;
550 }
551
552 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
553                                                     unsigned long *next_delay)
554 {
555         struct ieee80211_sub_if_data *sdata;
556
557         /*
558          * notify the AP about us leaving the channel and stop all STA interfaces
559          */
560         mutex_lock(&local->iflist_mtx);
561         list_for_each_entry(sdata, &local->interfaces, list) {
562                 if (!netif_running(sdata->dev))
563                         continue;
564
565                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
566                         netif_stop_queue(sdata->dev);
567                         if (sdata->u.mgd.associated)
568                                 ieee80211_scan_ps_enable(sdata);
569                 }
570         }
571         mutex_unlock(&local->iflist_mtx);
572
573         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
574
575         /* advance to the next channel to be scanned */
576         *next_delay = HZ / 10;
577         local->next_scan_state = SCAN_SET_CHANNEL;
578 }
579
580 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
581                                                     unsigned long *next_delay)
582 {
583         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
584
585         /* switch back to the operating channel */
586         local->scan_channel = NULL;
587         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
588
589         /*
590          * notify the AP about us being back and restart all STA interfaces
591          */
592         mutex_lock(&local->iflist_mtx);
593         list_for_each_entry(sdata, &local->interfaces, list) {
594                 if (!netif_running(sdata->dev))
595                         continue;
596
597                 /* Tell AP we're back */
598                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
599                         if (sdata->u.mgd.associated)
600                                 ieee80211_scan_ps_disable(sdata);
601                         netif_wake_queue(sdata->dev);
602                 }
603         }
604         mutex_unlock(&local->iflist_mtx);
605
606         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
607
608         *next_delay = HZ / 5;
609         local->next_scan_state = SCAN_DECISION;
610 }
611
612 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
613                                              unsigned long *next_delay)
614 {
615         int skip;
616         struct ieee80211_channel *chan;
617
618         skip = 0;
619         chan = local->scan_req->channels[local->scan_channel_idx];
620
621         local->scan_channel = chan;
622         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
623                 skip = 1;
624
625         /* advance state machine to next channel/band */
626         local->scan_channel_idx++;
627
628         if (skip) {
629                 /* if we skip this channel return to the decision state */
630                 local->next_scan_state = SCAN_DECISION;
631                 return;
632         }
633
634         /*
635          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
636          * (which unfortunately doesn't say _why_ step a) is done,
637          * but it waits for the probe delay or until a frame is
638          * received - and the received frame would update the NAV).
639          * For now, we do not support waiting until a frame is
640          * received.
641          *
642          * In any case, it is not necessary for a passive scan.
643          */
644         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
645             !local->scan_req->n_ssids) {
646                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
647                 local->next_scan_state = SCAN_DECISION;
648                 return;
649         }
650
651         /* active scan, send probes */
652         *next_delay = IEEE80211_PROBE_DELAY;
653         local->next_scan_state = SCAN_SEND_PROBE;
654 }
655
656 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
657                                             unsigned long *next_delay)
658 {
659         int i;
660         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
661
662         for (i = 0; i < local->scan_req->n_ssids; i++)
663                 ieee80211_send_probe_req(
664                         sdata, NULL,
665                         local->scan_req->ssids[i].ssid,
666                         local->scan_req->ssids[i].ssid_len,
667                         local->scan_req->ie, local->scan_req->ie_len);
668
669         /*
670          * After sending probe requests, wait for probe responses
671          * on the channel.
672          */
673         *next_delay = IEEE80211_CHANNEL_TIME;
674         local->next_scan_state = SCAN_DECISION;
675 }
676
677 void ieee80211_scan_work(struct work_struct *work)
678 {
679         struct ieee80211_local *local =
680                 container_of(work, struct ieee80211_local, scan_work.work);
681         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
682         unsigned long next_delay = 0;
683
684         mutex_lock(&local->scan_mtx);
685         if (!sdata || !local->scan_req) {
686                 mutex_unlock(&local->scan_mtx);
687                 return;
688         }
689
690         if (local->hw_scan_req) {
691                 int rc = drv_hw_scan(local, local->hw_scan_req);
692                 mutex_unlock(&local->scan_mtx);
693                 if (rc)
694                         ieee80211_scan_completed(&local->hw, true);
695                 return;
696         }
697
698         if (local->scan_req && !local->scanning) {
699                 struct cfg80211_scan_request *req = local->scan_req;
700                 int rc;
701
702                 local->scan_req = NULL;
703                 local->scan_sdata = NULL;
704
705                 rc = __ieee80211_start_scan(sdata, req);
706                 mutex_unlock(&local->scan_mtx);
707
708                 if (rc)
709                         ieee80211_scan_completed(&local->hw, true);
710                 return;
711         }
712
713         mutex_unlock(&local->scan_mtx);
714
715         /*
716          * Avoid re-scheduling when the sdata is going away.
717          */
718         if (!netif_running(sdata->dev)) {
719                 ieee80211_scan_completed(&local->hw, true);
720                 return;
721         }
722
723         /*
724          * as long as no delay is required advance immediately
725          * without scheduling a new work
726          */
727         do {
728                 switch (local->next_scan_state) {
729                 case SCAN_DECISION:
730                         if (ieee80211_scan_state_decision(local, &next_delay))
731                                 return;
732                         break;
733                 case SCAN_SET_CHANNEL:
734                         ieee80211_scan_state_set_channel(local, &next_delay);
735                         break;
736                 case SCAN_SEND_PROBE:
737                         ieee80211_scan_state_send_probe(local, &next_delay);
738                         break;
739                 case SCAN_LEAVE_OPER_CHANNEL:
740                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
741                         break;
742                 case SCAN_ENTER_OPER_CHANNEL:
743                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
744                         break;
745                 }
746         } while (next_delay == 0);
747
748         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
749 }
750
751 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
752                            struct cfg80211_scan_request *req)
753 {
754         int res;
755
756         mutex_lock(&sdata->local->scan_mtx);
757         res = __ieee80211_start_scan(sdata, req);
758         mutex_unlock(&sdata->local->scan_mtx);
759
760         return res;
761 }
762
763 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
764                                     const u8 *ssid, u8 ssid_len)
765 {
766         struct ieee80211_local *local = sdata->local;
767         int ret = -EBUSY;
768
769         mutex_lock(&local->scan_mtx);
770
771         /* busy scanning */
772         if (local->scan_req)
773                 goto unlock;
774
775         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
776         local->int_scan_req->ssids[0].ssid_len = ssid_len;
777
778         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
779  unlock:
780         mutex_unlock(&local->scan_mtx);
781         return ret;
782 }
783
784 void ieee80211_scan_cancel(struct ieee80211_local *local)
785 {
786         bool abortscan;
787
788         cancel_delayed_work_sync(&local->scan_work);
789
790         /*
791          * Only call this function when a scan can't be
792          * queued -- mostly at suspend under RTNL.
793          */
794         mutex_lock(&local->scan_mtx);
795         abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
796                     (!local->scanning && local->scan_req);
797         mutex_unlock(&local->scan_mtx);
798
799         if (abortscan)
800                 ieee80211_scan_completed(&local->hw, true);
801 }