mac80211: correctly close cancelled scans
[linux-3.10.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/if_arp.h>
16 #include <linux/etherdevice.h>
17 #include <linux/rtnetlink.h>
18 #include <linux/pm_qos.h>
19 #include <net/sch_generic.h>
20 #include <linux/slab.h>
21 #include <linux/export.h>
22 #include <net/mac80211.h>
23
24 #include "ieee80211_i.h"
25 #include "driver-ops.h"
26 #include "mesh.h"
27
28 #define IEEE80211_PROBE_DELAY (HZ / 33)
29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
31
32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
33                           struct ieee80211_bss *bss)
34 {
35         if (!bss)
36                 return;
37         cfg80211_put_bss(local->hw.wiphy,
38                          container_of((void *)bss, struct cfg80211_bss, priv));
39 }
40
41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
42 {
43         u8 qos_info;
44
45         if (elems->wmm_info && elems->wmm_info_len == 7
46             && elems->wmm_info[5] == 1)
47                 qos_info = elems->wmm_info[6];
48         else if (elems->wmm_param && elems->wmm_param_len == 24
49                  && elems->wmm_param[5] == 1)
50                 qos_info = elems->wmm_param[6];
51         else
52                 /* no valid wmm information or parameter element found */
53                 return false;
54
55         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
56 }
57
58 struct ieee80211_bss *
59 ieee80211_bss_info_update(struct ieee80211_local *local,
60                           struct ieee80211_rx_status *rx_status,
61                           struct ieee80211_mgmt *mgmt, size_t len,
62                           struct ieee802_11_elems *elems,
63                           struct ieee80211_channel *channel)
64 {
65         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
66         struct cfg80211_bss *cbss;
67         struct ieee80211_bss *bss;
68         int clen, srlen;
69         s32 signal = 0;
70
71         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
72                 signal = rx_status->signal * 100;
73         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
74                 signal = (rx_status->signal * 100) / local->hw.max_signal;
75
76         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
77                                          mgmt, len, signal, GFP_ATOMIC);
78         if (!cbss)
79                 return NULL;
80
81         bss = (void *)cbss->priv;
82
83         if (beacon)
84                 bss->device_ts_beacon = rx_status->device_timestamp;
85         else
86                 bss->device_ts_presp = rx_status->device_timestamp;
87
88         if (elems->parse_error) {
89                 if (beacon)
90                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
91                 else
92                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
93         } else {
94                 if (beacon)
95                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
96                 else
97                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
98         }
99
100         /* save the ERP value so that it is available at association time */
101         if (elems->erp_info && (!elems->parse_error ||
102                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
103                 bss->erp_value = elems->erp_info[0];
104                 bss->has_erp_value = true;
105                 if (!elems->parse_error)
106                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
107         }
108
109         /* replace old supported rates if we get new values */
110         if (!elems->parse_error ||
111             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
112                 srlen = 0;
113                 if (elems->supp_rates) {
114                         clen = IEEE80211_MAX_SUPP_RATES;
115                         if (clen > elems->supp_rates_len)
116                                 clen = elems->supp_rates_len;
117                         memcpy(bss->supp_rates, elems->supp_rates, clen);
118                         srlen += clen;
119                 }
120                 if (elems->ext_supp_rates) {
121                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
122                         if (clen > elems->ext_supp_rates_len)
123                                 clen = elems->ext_supp_rates_len;
124                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
125                                clen);
126                         srlen += clen;
127                 }
128                 if (srlen) {
129                         bss->supp_rates_len = srlen;
130                         if (!elems->parse_error)
131                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
132                 }
133         }
134
135         if (!elems->parse_error ||
136             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
137                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
138                 bss->uapsd_supported = is_uapsd_supported(elems);
139                 if (!elems->parse_error)
140                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
141         }
142
143         return bss;
144 }
145
146 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
147 {
148         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
149         struct ieee80211_sub_if_data *sdata1, *sdata2;
150         struct ieee80211_mgmt *mgmt = (void *)skb->data;
151         struct ieee80211_bss *bss;
152         u8 *elements;
153         struct ieee80211_channel *channel;
154         size_t baselen;
155         struct ieee802_11_elems elems;
156
157         if (skb->len < 24 ||
158             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
159              !ieee80211_is_beacon(mgmt->frame_control)))
160                 return;
161
162         sdata1 = rcu_dereference(local->scan_sdata);
163         sdata2 = rcu_dereference(local->sched_scan_sdata);
164
165         if (likely(!sdata1 && !sdata2))
166                 return;
167
168         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
169                 /* ignore ProbeResp to foreign address */
170                 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
171                     (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
172                         return;
173
174                 elements = mgmt->u.probe_resp.variable;
175                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
176         } else {
177                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
178                 elements = mgmt->u.beacon.variable;
179         }
180
181         if (baselen > skb->len)
182                 return;
183
184         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
185
186         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
187
188         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
189                 return;
190
191         bss = ieee80211_bss_info_update(local, rx_status,
192                                         mgmt, skb->len, &elems,
193                                         channel);
194         if (bss)
195                 ieee80211_rx_bss_put(local, bss);
196 }
197
198 /* return false if no more work */
199 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
200 {
201         struct cfg80211_scan_request *req = local->scan_req;
202         enum ieee80211_band band;
203         int i, ielen, n_chans;
204
205         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
206                 return false;
207
208         do {
209                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
210                         return false;
211
212                 band = local->hw_scan_band;
213                 n_chans = 0;
214                 for (i = 0; i < req->n_channels; i++) {
215                         if (req->channels[i]->band == band) {
216                                 local->hw_scan_req->channels[n_chans] =
217                                                         req->channels[i];
218                                 n_chans++;
219                         }
220                 }
221
222                 local->hw_scan_band++;
223         } while (!n_chans);
224
225         local->hw_scan_req->n_channels = n_chans;
226
227         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
228                                          local->hw_scan_ies_bufsize,
229                                          req->ie, req->ie_len, band,
230                                          req->rates[band], 0);
231         local->hw_scan_req->ie_len = ielen;
232         local->hw_scan_req->no_cck = req->no_cck;
233
234         return true;
235 }
236
237 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
238                                        bool was_hw_scan)
239 {
240         struct ieee80211_local *local = hw_to_local(hw);
241
242         lockdep_assert_held(&local->mtx);
243
244         /*
245          * It's ok to abort a not-yet-running scan (that
246          * we have one at all will be verified by checking
247          * local->scan_req next), but not to complete it
248          * successfully.
249          */
250         if (WARN_ON(!local->scanning && !aborted))
251                 aborted = true;
252
253         if (WARN_ON(!local->scan_req))
254                 return;
255
256         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
257                 int rc;
258
259                 rc = drv_hw_scan(local,
260                         rcu_dereference_protected(local->scan_sdata,
261                                                   lockdep_is_held(&local->mtx)),
262                         local->hw_scan_req);
263
264                 if (rc == 0)
265                         return;
266         }
267
268         kfree(local->hw_scan_req);
269         local->hw_scan_req = NULL;
270
271         if (local->scan_req != local->int_scan_req)
272                 cfg80211_scan_done(local->scan_req, aborted);
273         local->scan_req = NULL;
274         rcu_assign_pointer(local->scan_sdata, NULL);
275
276         local->scanning = 0;
277         local->scan_channel = NULL;
278
279         /* Set power back to normal operating levels. */
280         ieee80211_hw_config(local, 0);
281
282         if (!was_hw_scan) {
283                 ieee80211_configure_filter(local);
284                 drv_sw_scan_complete(local);
285                 ieee80211_offchannel_return(local);
286         }
287
288         ieee80211_recalc_idle(local);
289
290         ieee80211_mlme_notify_scan_completed(local);
291         ieee80211_ibss_notify_scan_completed(local);
292         ieee80211_mesh_notify_scan_completed(local);
293         ieee80211_start_next_roc(local);
294 }
295
296 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
297 {
298         struct ieee80211_local *local = hw_to_local(hw);
299
300         trace_api_scan_completed(local, aborted);
301
302         set_bit(SCAN_COMPLETED, &local->scanning);
303         if (aborted)
304                 set_bit(SCAN_ABORTED, &local->scanning);
305         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
306 }
307 EXPORT_SYMBOL(ieee80211_scan_completed);
308
309 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
310 {
311         /* Software scan is not supported in multi-channel cases */
312         if (local->use_chanctx)
313                 return -EOPNOTSUPP;
314
315         /*
316          * Hardware/driver doesn't support hw_scan, so use software
317          * scanning instead. First send a nullfunc frame with power save
318          * bit on so that AP will buffer the frames for us while we are not
319          * listening, then send probe requests to each channel and wait for
320          * the responses. After all channels are scanned, tune back to the
321          * original channel and send a nullfunc frame with power save bit
322          * off to trigger the AP to send us all the buffered frames.
323          *
324          * Note that while local->sw_scanning is true everything else but
325          * nullfunc frames and probe requests will be dropped in
326          * ieee80211_tx_h_check_assoc().
327          */
328         drv_sw_scan_start(local);
329
330         local->leave_oper_channel_time = jiffies;
331         local->next_scan_state = SCAN_DECISION;
332         local->scan_channel_idx = 0;
333
334         ieee80211_offchannel_stop_vifs(local);
335
336         /* ensure nullfunc is transmitted before leaving operating channel */
337         ieee80211_flush_queues(local, NULL);
338
339         ieee80211_configure_filter(local);
340
341         /* We need to set power level at maximum rate for scanning. */
342         ieee80211_hw_config(local, 0);
343
344         ieee80211_queue_delayed_work(&local->hw,
345                                      &local->scan_work, 0);
346
347         return 0;
348 }
349
350 static bool ieee80211_can_scan(struct ieee80211_local *local,
351                                struct ieee80211_sub_if_data *sdata)
352 {
353         if (local->radar_detect_enabled)
354                 return false;
355
356         if (!list_empty(&local->roc_list))
357                 return false;
358
359         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
360             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
361                                   IEEE80211_STA_CONNECTION_POLL))
362                 return false;
363
364         return true;
365 }
366
367 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
368 {
369         lockdep_assert_held(&local->mtx);
370
371         if (!local->scan_req || local->scanning)
372                 return;
373
374         if (!ieee80211_can_scan(local,
375                                 rcu_dereference_protected(
376                                         local->scan_sdata,
377                                         lockdep_is_held(&local->mtx))))
378                 return;
379
380         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
381                                      round_jiffies_relative(0));
382 }
383
384 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
385                                             unsigned long *next_delay)
386 {
387         int i;
388         struct ieee80211_sub_if_data *sdata;
389         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
390         u32 tx_flags;
391
392         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
393         if (local->scan_req->no_cck)
394                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
395
396         sdata = rcu_dereference_protected(local->scan_sdata,
397                                           lockdep_is_held(&local->mtx));
398
399         for (i = 0; i < local->scan_req->n_ssids; i++)
400                 ieee80211_send_probe_req(
401                         sdata, NULL,
402                         local->scan_req->ssids[i].ssid,
403                         local->scan_req->ssids[i].ssid_len,
404                         local->scan_req->ie, local->scan_req->ie_len,
405                         local->scan_req->rates[band], false,
406                         tx_flags, local->hw.conf.chandef.chan, true);
407
408         /*
409          * After sending probe requests, wait for probe responses
410          * on the channel.
411          */
412         *next_delay = IEEE80211_CHANNEL_TIME;
413         local->next_scan_state = SCAN_DECISION;
414 }
415
416 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
417                                   struct cfg80211_scan_request *req)
418 {
419         struct ieee80211_local *local = sdata->local;
420         int rc;
421
422         lockdep_assert_held(&local->mtx);
423
424         if (local->scan_req)
425                 return -EBUSY;
426
427         if (!ieee80211_can_scan(local, sdata)) {
428                 /* wait for the work to finish/time out */
429                 local->scan_req = req;
430                 rcu_assign_pointer(local->scan_sdata, sdata);
431                 return 0;
432         }
433
434         if (local->ops->hw_scan) {
435                 u8 *ies;
436
437                 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
438                                              local->scan_ies_len +
439                                              req->ie_len;
440                 local->hw_scan_req = kmalloc(
441                                 sizeof(*local->hw_scan_req) +
442                                 req->n_channels * sizeof(req->channels[0]) +
443                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
444                 if (!local->hw_scan_req)
445                         return -ENOMEM;
446
447                 local->hw_scan_req->ssids = req->ssids;
448                 local->hw_scan_req->n_ssids = req->n_ssids;
449                 ies = (u8 *)local->hw_scan_req +
450                         sizeof(*local->hw_scan_req) +
451                         req->n_channels * sizeof(req->channels[0]);
452                 local->hw_scan_req->ie = ies;
453                 local->hw_scan_req->flags = req->flags;
454
455                 local->hw_scan_band = 0;
456
457                 /*
458                  * After allocating local->hw_scan_req, we must
459                  * go through until ieee80211_prep_hw_scan(), so
460                  * anything that might be changed here and leave
461                  * this function early must not go after this
462                  * allocation.
463                  */
464         }
465
466         local->scan_req = req;
467         rcu_assign_pointer(local->scan_sdata, sdata);
468
469         if (local->ops->hw_scan) {
470                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
471         } else if ((req->n_channels == 1) &&
472                    (req->channels[0] == local->_oper_chandef.chan)) {
473                 /*
474                  * If we are scanning only on the operating channel
475                  * then we do not need to stop normal activities
476                  */
477                 unsigned long next_delay;
478
479                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
480
481                 ieee80211_recalc_idle(local);
482
483                 /* Notify driver scan is starting, keep order of operations
484                  * same as normal software scan, in case that matters. */
485                 drv_sw_scan_start(local);
486
487                 ieee80211_configure_filter(local); /* accept probe-responses */
488
489                 /* We need to ensure power level is at max for scanning. */
490                 ieee80211_hw_config(local, 0);
491
492                 if ((req->channels[0]->flags &
493                      IEEE80211_CHAN_PASSIVE_SCAN) ||
494                     !local->scan_req->n_ssids) {
495                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
496                 } else {
497                         ieee80211_scan_state_send_probe(local, &next_delay);
498                         next_delay = IEEE80211_CHANNEL_TIME;
499                 }
500
501                 /* Now, just wait a bit and we are all done! */
502                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
503                                              next_delay);
504                 return 0;
505         } else {
506                 /* Do normal software scan */
507                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
508         }
509
510         ieee80211_recalc_idle(local);
511
512         if (local->ops->hw_scan) {
513                 WARN_ON(!ieee80211_prep_hw_scan(local));
514                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
515         } else
516                 rc = ieee80211_start_sw_scan(local);
517
518         if (rc) {
519                 kfree(local->hw_scan_req);
520                 local->hw_scan_req = NULL;
521                 local->scanning = 0;
522
523                 ieee80211_recalc_idle(local);
524
525                 local->scan_req = NULL;
526                 rcu_assign_pointer(local->scan_sdata, NULL);
527         }
528
529         return rc;
530 }
531
532 static unsigned long
533 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
534 {
535         /*
536          * TODO: channel switching also consumes quite some time,
537          * add that delay as well to get a better estimation
538          */
539         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
540                 return IEEE80211_PASSIVE_CHANNEL_TIME;
541         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
542 }
543
544 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
545                                           unsigned long *next_delay)
546 {
547         bool associated = false;
548         bool tx_empty = true;
549         bool bad_latency;
550         struct ieee80211_sub_if_data *sdata;
551         struct ieee80211_channel *next_chan;
552         enum mac80211_scan_state next_scan_state;
553
554         /*
555          * check if at least one STA interface is associated,
556          * check if at least one STA interface has pending tx frames
557          * and grab the lowest used beacon interval
558          */
559         mutex_lock(&local->iflist_mtx);
560         list_for_each_entry(sdata, &local->interfaces, list) {
561                 if (!ieee80211_sdata_running(sdata))
562                         continue;
563
564                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
565                         if (sdata->u.mgd.associated) {
566                                 associated = true;
567
568                                 if (!qdisc_all_tx_empty(sdata->dev)) {
569                                         tx_empty = false;
570                                         break;
571                                 }
572                         }
573                 }
574         }
575         mutex_unlock(&local->iflist_mtx);
576
577         next_chan = local->scan_req->channels[local->scan_channel_idx];
578
579         /*
580          * we're currently scanning a different channel, let's
581          * see if we can scan another channel without interfering
582          * with the current traffic situation.
583          *
584          * Keep good latency, do not stay off-channel more than 125 ms.
585          */
586
587         bad_latency = time_after(jiffies +
588                                  ieee80211_scan_get_channel_time(next_chan),
589                                  local->leave_oper_channel_time + HZ / 8);
590
591         if (associated && !tx_empty) {
592                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
593                         next_scan_state = SCAN_ABORT;
594                 else
595                         next_scan_state = SCAN_SUSPEND;
596         } else if (associated && bad_latency) {
597                 next_scan_state = SCAN_SUSPEND;
598         } else {
599                 next_scan_state = SCAN_SET_CHANNEL;
600         }
601
602         local->next_scan_state = next_scan_state;
603
604         *next_delay = 0;
605 }
606
607 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
608                                              unsigned long *next_delay)
609 {
610         int skip;
611         struct ieee80211_channel *chan;
612
613         skip = 0;
614         chan = local->scan_req->channels[local->scan_channel_idx];
615
616         local->scan_channel = chan;
617
618         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
619                 skip = 1;
620
621         /* advance state machine to next channel/band */
622         local->scan_channel_idx++;
623
624         if (skip) {
625                 /* if we skip this channel return to the decision state */
626                 local->next_scan_state = SCAN_DECISION;
627                 return;
628         }
629
630         /*
631          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
632          * (which unfortunately doesn't say _why_ step a) is done,
633          * but it waits for the probe delay or until a frame is
634          * received - and the received frame would update the NAV).
635          * For now, we do not support waiting until a frame is
636          * received.
637          *
638          * In any case, it is not necessary for a passive scan.
639          */
640         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
641             !local->scan_req->n_ssids) {
642                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
643                 local->next_scan_state = SCAN_DECISION;
644                 return;
645         }
646
647         /* active scan, send probes */
648         *next_delay = IEEE80211_PROBE_DELAY;
649         local->next_scan_state = SCAN_SEND_PROBE;
650 }
651
652 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
653                                          unsigned long *next_delay)
654 {
655         /* switch back to the operating channel */
656         local->scan_channel = NULL;
657         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
658
659         /* disable PS */
660         ieee80211_offchannel_return(local);
661
662         *next_delay = HZ / 5;
663         /* afterwards, resume scan & go to next channel */
664         local->next_scan_state = SCAN_RESUME;
665 }
666
667 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
668                                         unsigned long *next_delay)
669 {
670         ieee80211_offchannel_stop_vifs(local);
671
672         if (local->ops->flush) {
673                 ieee80211_flush_queues(local, NULL);
674                 *next_delay = 0;
675         } else
676                 *next_delay = HZ / 10;
677
678         /* remember when we left the operating channel */
679         local->leave_oper_channel_time = jiffies;
680
681         /* advance to the next channel to be scanned */
682         local->next_scan_state = SCAN_SET_CHANNEL;
683 }
684
685 void ieee80211_scan_work(struct work_struct *work)
686 {
687         struct ieee80211_local *local =
688                 container_of(work, struct ieee80211_local, scan_work.work);
689         struct ieee80211_sub_if_data *sdata;
690         unsigned long next_delay = 0;
691         bool aborted, hw_scan;
692
693         mutex_lock(&local->mtx);
694
695         sdata = rcu_dereference_protected(local->scan_sdata,
696                                           lockdep_is_held(&local->mtx));
697
698         /* When scanning on-channel, the first-callback means completed. */
699         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
700                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
701                 goto out_complete;
702         }
703
704         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
705                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
706                 goto out_complete;
707         }
708
709         if (!sdata || !local->scan_req)
710                 goto out;
711
712         if (local->scan_req && !local->scanning) {
713                 struct cfg80211_scan_request *req = local->scan_req;
714                 int rc;
715
716                 local->scan_req = NULL;
717                 rcu_assign_pointer(local->scan_sdata, NULL);
718
719                 rc = __ieee80211_start_scan(sdata, req);
720                 if (rc) {
721                         /* need to complete scan in cfg80211 */
722                         local->scan_req = req;
723                         aborted = true;
724                         goto out_complete;
725                 } else
726                         goto out;
727         }
728
729         /*
730          * Avoid re-scheduling when the sdata is going away.
731          */
732         if (!ieee80211_sdata_running(sdata)) {
733                 aborted = true;
734                 goto out_complete;
735         }
736
737         /*
738          * as long as no delay is required advance immediately
739          * without scheduling a new work
740          */
741         do {
742                 if (!ieee80211_sdata_running(sdata)) {
743                         aborted = true;
744                         goto out_complete;
745                 }
746
747                 switch (local->next_scan_state) {
748                 case SCAN_DECISION:
749                         /* if no more bands/channels left, complete scan */
750                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
751                                 aborted = false;
752                                 goto out_complete;
753                         }
754                         ieee80211_scan_state_decision(local, &next_delay);
755                         break;
756                 case SCAN_SET_CHANNEL:
757                         ieee80211_scan_state_set_channel(local, &next_delay);
758                         break;
759                 case SCAN_SEND_PROBE:
760                         ieee80211_scan_state_send_probe(local, &next_delay);
761                         break;
762                 case SCAN_SUSPEND:
763                         ieee80211_scan_state_suspend(local, &next_delay);
764                         break;
765                 case SCAN_RESUME:
766                         ieee80211_scan_state_resume(local, &next_delay);
767                         break;
768                 case SCAN_ABORT:
769                         aborted = true;
770                         goto out_complete;
771                 }
772         } while (next_delay == 0);
773
774         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
775         goto out;
776
777 out_complete:
778         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
779         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
780 out:
781         mutex_unlock(&local->mtx);
782 }
783
784 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
785                            struct cfg80211_scan_request *req)
786 {
787         int res;
788
789         mutex_lock(&sdata->local->mtx);
790         res = __ieee80211_start_scan(sdata, req);
791         mutex_unlock(&sdata->local->mtx);
792
793         return res;
794 }
795
796 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
797                                 const u8 *ssid, u8 ssid_len,
798                                 struct ieee80211_channel *chan)
799 {
800         struct ieee80211_local *local = sdata->local;
801         int ret = -EBUSY;
802         enum ieee80211_band band;
803
804         mutex_lock(&local->mtx);
805
806         /* busy scanning */
807         if (local->scan_req)
808                 goto unlock;
809
810         /* fill internal scan request */
811         if (!chan) {
812                 int i, max_n;
813                 int n_ch = 0;
814
815                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
816                         if (!local->hw.wiphy->bands[band])
817                                 continue;
818
819                         max_n = local->hw.wiphy->bands[band]->n_channels;
820                         for (i = 0; i < max_n; i++) {
821                                 struct ieee80211_channel *tmp_ch =
822                                     &local->hw.wiphy->bands[band]->channels[i];
823
824                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
825                                                      IEEE80211_CHAN_DISABLED))
826                                         continue;
827
828                                 local->int_scan_req->channels[n_ch] = tmp_ch;
829                                 n_ch++;
830                         }
831                 }
832
833                 if (WARN_ON_ONCE(n_ch == 0))
834                         goto unlock;
835
836                 local->int_scan_req->n_channels = n_ch;
837         } else {
838                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
839                                                 IEEE80211_CHAN_DISABLED)))
840                         goto unlock;
841
842                 local->int_scan_req->channels[0] = chan;
843                 local->int_scan_req->n_channels = 1;
844         }
845
846         local->int_scan_req->ssids = &local->scan_ssid;
847         local->int_scan_req->n_ssids = 1;
848         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
849         local->int_scan_req->ssids[0].ssid_len = ssid_len;
850
851         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
852  unlock:
853         mutex_unlock(&local->mtx);
854         return ret;
855 }
856
857 /*
858  * Only call this function when a scan can't be queued -- under RTNL.
859  */
860 void ieee80211_scan_cancel(struct ieee80211_local *local)
861 {
862         /*
863          * We are canceling software scan, or deferred scan that was not
864          * yet really started (see __ieee80211_start_scan ).
865          *
866          * Regarding hardware scan:
867          * - we can not call  __ieee80211_scan_completed() as when
868          *   SCAN_HW_SCANNING bit is set this function change
869          *   local->hw_scan_req to operate on 5G band, what race with
870          *   driver which can use local->hw_scan_req
871          *
872          * - we can not cancel scan_work since driver can schedule it
873          *   by ieee80211_scan_completed(..., true) to finish scan
874          *
875          * Hence we only call the cancel_hw_scan() callback, but the low-level
876          * driver is still responsible for calling ieee80211_scan_completed()
877          * after the scan was completed/aborted.
878          */
879
880         mutex_lock(&local->mtx);
881         if (!local->scan_req)
882                 goto out;
883
884         /*
885          * We have a scan running and the driver already reported completion,
886          * but the worker hasn't run yet or is stuck on the mutex - mark it as
887          * cancelled.
888          */
889         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
890             test_bit(SCAN_COMPLETED, &local->scanning)) {
891                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
892                 goto out;
893         }
894
895         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
896                 /*
897                  * Make sure that __ieee80211_scan_completed doesn't trigger a
898                  * scan on another band.
899                  */
900                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
901                 if (local->ops->cancel_hw_scan)
902                         drv_cancel_hw_scan(local,
903                                 rcu_dereference_protected(local->scan_sdata,
904                                                 lockdep_is_held(&local->mtx)));
905                 goto out;
906         }
907
908         /*
909          * If the work is currently running, it must be blocked on
910          * the mutex, but we'll set scan_sdata = NULL and it'll
911          * simply exit once it acquires the mutex.
912          */
913         cancel_delayed_work(&local->scan_work);
914         /* and clean up */
915         __ieee80211_scan_completed(&local->hw, true, false);
916 out:
917         mutex_unlock(&local->mtx);
918 }
919
920 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
921                                        struct cfg80211_sched_scan_request *req)
922 {
923         struct ieee80211_local *local = sdata->local;
924         struct ieee80211_sched_scan_ies sched_scan_ies = {};
925         int ret, i, iebufsz;
926
927         iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
928                   local->scan_ies_len + req->ie_len;
929
930         mutex_lock(&local->mtx);
931
932         if (rcu_access_pointer(local->sched_scan_sdata)) {
933                 ret = -EBUSY;
934                 goto out;
935         }
936
937         if (!local->ops->sched_scan_start) {
938                 ret = -ENOTSUPP;
939                 goto out;
940         }
941
942         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
943                 if (!local->hw.wiphy->bands[i])
944                         continue;
945
946                 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
947                 if (!sched_scan_ies.ie[i]) {
948                         ret = -ENOMEM;
949                         goto out_free;
950                 }
951
952                 sched_scan_ies.len[i] =
953                         ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
954                                                  iebufsz, req->ie, req->ie_len,
955                                                  i, (u32) -1, 0);
956         }
957
958         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
959         if (ret == 0)
960                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
961
962 out_free:
963         while (i > 0)
964                 kfree(sched_scan_ies.ie[--i]);
965 out:
966         mutex_unlock(&local->mtx);
967         return ret;
968 }
969
970 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
971 {
972         struct ieee80211_local *local = sdata->local;
973         int ret = 0;
974
975         mutex_lock(&local->mtx);
976
977         if (!local->ops->sched_scan_stop) {
978                 ret = -ENOTSUPP;
979                 goto out;
980         }
981
982         if (rcu_access_pointer(local->sched_scan_sdata))
983                 drv_sched_scan_stop(local, sdata);
984
985 out:
986         mutex_unlock(&local->mtx);
987
988         return ret;
989 }
990
991 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
992 {
993         struct ieee80211_local *local = hw_to_local(hw);
994
995         trace_api_sched_scan_results(local);
996
997         cfg80211_sched_scan_results(hw->wiphy);
998 }
999 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1000
1001 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1002 {
1003         struct ieee80211_local *local =
1004                 container_of(work, struct ieee80211_local,
1005                              sched_scan_stopped_work);
1006
1007         mutex_lock(&local->mtx);
1008
1009         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1010                 mutex_unlock(&local->mtx);
1011                 return;
1012         }
1013
1014         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1015
1016         mutex_unlock(&local->mtx);
1017
1018         cfg80211_sched_scan_stopped(local->hw.wiphy);
1019 }
1020
1021 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1022 {
1023         struct ieee80211_local *local = hw_to_local(hw);
1024
1025         trace_api_sched_scan_stopped(local);
1026
1027         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1028 }
1029 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);