Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[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/if_arp.h>
16 #include <linux/rtnetlink.h>
17 #include <linux/pm_qos_params.h>
18 #include <net/sch_generic.h>
19 #include <linux/slab.h>
20 #include <net/mac80211.h>
21
22 #include "ieee80211_i.h"
23 #include "driver-ops.h"
24 #include "mesh.h"
25
26 #define IEEE80211_PROBE_DELAY (HZ / 33)
27 #define IEEE80211_CHANNEL_TIME (HZ / 33)
28 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
29
30 struct ieee80211_bss *
31 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
32                      u8 *ssid, u8 ssid_len)
33 {
34         struct cfg80211_bss *cbss;
35
36         cbss = cfg80211_get_bss(local->hw.wiphy,
37                                 ieee80211_get_channel(local->hw.wiphy, freq),
38                                 bssid, ssid, ssid_len, 0, 0);
39         if (!cbss)
40                 return NULL;
41         return (void *)cbss->priv;
42 }
43
44 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
45 {
46         struct ieee80211_bss *bss = (void *)cbss->priv;
47
48         kfree(bss_mesh_id(bss));
49         kfree(bss_mesh_cfg(bss));
50 }
51
52 void ieee80211_rx_bss_put(struct ieee80211_local *local,
53                           struct ieee80211_bss *bss)
54 {
55         if (!bss)
56                 return;
57         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
58 }
59
60 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
61 {
62         u8 qos_info;
63
64         if (elems->wmm_info && elems->wmm_info_len == 7
65             && elems->wmm_info[5] == 1)
66                 qos_info = elems->wmm_info[6];
67         else if (elems->wmm_param && elems->wmm_param_len == 24
68                  && elems->wmm_param[5] == 1)
69                 qos_info = elems->wmm_param[6];
70         else
71                 /* no valid wmm information or parameter element found */
72                 return false;
73
74         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
75 }
76
77 struct ieee80211_bss *
78 ieee80211_bss_info_update(struct ieee80211_local *local,
79                           struct ieee80211_rx_status *rx_status,
80                           struct ieee80211_mgmt *mgmt,
81                           size_t len,
82                           struct ieee802_11_elems *elems,
83                           struct ieee80211_channel *channel,
84                           bool beacon)
85 {
86         struct cfg80211_bss *cbss;
87         struct ieee80211_bss *bss;
88         int clen, srlen;
89         s32 signal = 0;
90
91         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
92                 signal = rx_status->signal * 100;
93         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
94                 signal = (rx_status->signal * 100) / local->hw.max_signal;
95
96         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
97                                          mgmt, len, signal, GFP_ATOMIC);
98
99         if (!cbss)
100                 return NULL;
101
102         cbss->free_priv = ieee80211_rx_bss_free;
103         bss = (void *)cbss->priv;
104
105         /* save the ERP value so that it is available at association time */
106         if (elems->erp_info && elems->erp_info_len >= 1) {
107                 bss->erp_value = elems->erp_info[0];
108                 bss->has_erp_value = 1;
109         }
110
111         if (elems->tim) {
112                 struct ieee80211_tim_ie *tim_ie =
113                         (struct ieee80211_tim_ie *)elems->tim;
114                 bss->dtim_period = tim_ie->dtim_period;
115         }
116
117         /* If the beacon had no TIM IE, or it was invalid, use 1 */
118         if (beacon && !bss->dtim_period)
119                 bss->dtim_period = 1;
120
121         /* replace old supported rates if we get new values */
122         srlen = 0;
123         if (elems->supp_rates) {
124                 clen = IEEE80211_MAX_SUPP_RATES;
125                 if (clen > elems->supp_rates_len)
126                         clen = elems->supp_rates_len;
127                 memcpy(bss->supp_rates, elems->supp_rates, clen);
128                 srlen += clen;
129         }
130         if (elems->ext_supp_rates) {
131                 clen = IEEE80211_MAX_SUPP_RATES - srlen;
132                 if (clen > elems->ext_supp_rates_len)
133                         clen = elems->ext_supp_rates_len;
134                 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
135                 srlen += clen;
136         }
137         if (srlen)
138                 bss->supp_rates_len = srlen;
139
140         bss->wmm_used = elems->wmm_param || elems->wmm_info;
141         bss->uapsd_supported = is_uapsd_supported(elems);
142
143         if (!beacon)
144                 bss->last_probe_resp = jiffies;
145
146         return bss;
147 }
148
149 ieee80211_rx_result
150 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
151 {
152         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
153         struct ieee80211_mgmt *mgmt;
154         struct ieee80211_bss *bss;
155         u8 *elements;
156         struct ieee80211_channel *channel;
157         size_t baselen;
158         int freq;
159         __le16 fc;
160         bool presp, beacon = false;
161         struct ieee802_11_elems elems;
162
163         if (skb->len < 2)
164                 return RX_DROP_UNUSABLE;
165
166         mgmt = (struct ieee80211_mgmt *) skb->data;
167         fc = mgmt->frame_control;
168
169         if (ieee80211_is_ctl(fc))
170                 return RX_CONTINUE;
171
172         if (skb->len < 24)
173                 return RX_CONTINUE;
174
175         presp = ieee80211_is_probe_resp(fc);
176         if (presp) {
177                 /* ignore ProbeResp to foreign address */
178                 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
179                         return RX_DROP_MONITOR;
180
181                 presp = true;
182                 elements = mgmt->u.probe_resp.variable;
183                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
184         } else {
185                 beacon = ieee80211_is_beacon(fc);
186                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
187                 elements = mgmt->u.beacon.variable;
188         }
189
190         if (!presp && !beacon)
191                 return RX_CONTINUE;
192
193         if (baselen > skb->len)
194                 return RX_DROP_MONITOR;
195
196         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
197
198         if (elems.ds_params && elems.ds_params_len == 1)
199                 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
200                                                       rx_status->band);
201         else
202                 freq = rx_status->freq;
203
204         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
205
206         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
207                 return RX_DROP_MONITOR;
208
209         bss = ieee80211_bss_info_update(sdata->local, rx_status,
210                                         mgmt, skb->len, &elems,
211                                         channel, beacon);
212         if (bss)
213                 ieee80211_rx_bss_put(sdata->local, bss);
214
215         /* If we are on-operating-channel, and this packet is for the
216          * current channel, pass the pkt on up the stack so that
217          * the rest of the stack can make use of it.
218          */
219         if (ieee80211_cfg_on_oper_channel(sdata->local)
220             && (channel == sdata->local->oper_channel))
221                 return RX_CONTINUE;
222
223         dev_kfree_skb(skb);
224         return RX_QUEUED;
225 }
226
227 /* return false if no more work */
228 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
229 {
230         struct cfg80211_scan_request *req = local->scan_req;
231         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
232         enum ieee80211_band band;
233         int i, ielen, n_chans;
234
235         do {
236                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
237                         return false;
238
239                 band = local->hw_scan_band;
240                 n_chans = 0;
241                 for (i = 0; i < req->n_channels; i++) {
242                         if (req->channels[i]->band == band) {
243                                 local->hw_scan_req->channels[n_chans] =
244                                                         req->channels[i];
245                                 n_chans++;
246                         }
247                 }
248
249                 local->hw_scan_band++;
250         } while (!n_chans);
251
252         local->hw_scan_req->n_channels = n_chans;
253
254         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
255                                          req->ie, req->ie_len, band,
256                                          sdata->rc_rateidx_mask[band], 0);
257         local->hw_scan_req->ie_len = ielen;
258
259         return true;
260 }
261
262 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
263                                        bool was_hw_scan)
264 {
265         struct ieee80211_local *local = hw_to_local(hw);
266         bool on_oper_chan;
267         bool enable_beacons = false;
268
269         lockdep_assert_held(&local->mtx);
270
271         /*
272          * It's ok to abort a not-yet-running scan (that
273          * we have one at all will be verified by checking
274          * local->scan_req next), but not to complete it
275          * successfully.
276          */
277         if (WARN_ON(!local->scanning && !aborted))
278                 aborted = true;
279
280         if (WARN_ON(!local->scan_req))
281                 return;
282
283         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
284                 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
285                 if (rc == 0)
286                         return;
287         }
288
289         kfree(local->hw_scan_req);
290         local->hw_scan_req = NULL;
291
292         if (local->scan_req != local->int_scan_req)
293                 cfg80211_scan_done(local->scan_req, aborted);
294         local->scan_req = NULL;
295         local->scan_sdata = NULL;
296
297         local->scanning = 0;
298         local->scan_channel = NULL;
299
300         on_oper_chan = ieee80211_cfg_on_oper_channel(local);
301
302         if (was_hw_scan || !on_oper_chan)
303                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
304         else
305                 /* Set power back to normal operating levels. */
306                 ieee80211_hw_config(local, 0);
307
308         if (!was_hw_scan) {
309                 bool on_oper_chan2;
310                 ieee80211_configure_filter(local);
311                 drv_sw_scan_complete(local);
312                 on_oper_chan2 = ieee80211_cfg_on_oper_channel(local);
313                 /* We should always be on-channel at this point. */
314                 WARN_ON(!on_oper_chan2);
315                 if (on_oper_chan2 && (on_oper_chan != on_oper_chan2))
316                         enable_beacons = true;
317
318                 ieee80211_offchannel_return(local, enable_beacons, true);
319         }
320
321         ieee80211_recalc_idle(local);
322
323         ieee80211_mlme_notify_scan_completed(local);
324         ieee80211_ibss_notify_scan_completed(local);
325         ieee80211_mesh_notify_scan_completed(local);
326         ieee80211_queue_work(&local->hw, &local->work_work);
327 }
328
329 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
330 {
331         struct ieee80211_local *local = hw_to_local(hw);
332
333         trace_api_scan_completed(local, aborted);
334
335         set_bit(SCAN_COMPLETED, &local->scanning);
336         if (aborted)
337                 set_bit(SCAN_ABORTED, &local->scanning);
338         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
339 }
340 EXPORT_SYMBOL(ieee80211_scan_completed);
341
342 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
343 {
344         /*
345          * Hardware/driver doesn't support hw_scan, so use software
346          * scanning instead. First send a nullfunc frame with power save
347          * bit on so that AP will buffer the frames for us while we are not
348          * listening, then send probe requests to each channel and wait for
349          * the responses. After all channels are scanned, tune back to the
350          * original channel and send a nullfunc frame with power save bit
351          * off to trigger the AP to send us all the buffered frames.
352          *
353          * Note that while local->sw_scanning is true everything else but
354          * nullfunc frames and probe requests will be dropped in
355          * ieee80211_tx_h_check_assoc().
356          */
357         drv_sw_scan_start(local);
358
359         local->leave_oper_channel_time = 0;
360         local->next_scan_state = SCAN_DECISION;
361         local->scan_channel_idx = 0;
362
363         /* We always want to use off-channel PS, even if we
364          * are not really leaving oper-channel.  Don't
365          * tell the AP though, as long as we are on-channel.
366          */
367         ieee80211_offchannel_enable_all_ps(local, false);
368
369         ieee80211_configure_filter(local);
370
371         /* We need to set power level at maximum rate for scanning. */
372         ieee80211_hw_config(local, 0);
373
374         ieee80211_queue_delayed_work(&local->hw,
375                                      &local->scan_work,
376                                      IEEE80211_CHANNEL_TIME);
377
378         return 0;
379 }
380
381
382 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
383                                   struct cfg80211_scan_request *req)
384 {
385         struct ieee80211_local *local = sdata->local;
386         int rc;
387
388         lockdep_assert_held(&local->mtx);
389
390         if (local->scan_req)
391                 return -EBUSY;
392
393         if (!list_empty(&local->work_list)) {
394                 /* wait for the work to finish/time out */
395                 local->scan_req = req;
396                 local->scan_sdata = sdata;
397                 return 0;
398         }
399
400         if (local->ops->hw_scan) {
401                 u8 *ies;
402
403                 local->hw_scan_req = kmalloc(
404                                 sizeof(*local->hw_scan_req) +
405                                 req->n_channels * sizeof(req->channels[0]) +
406                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
407                                 req->ie_len, GFP_KERNEL);
408                 if (!local->hw_scan_req)
409                         return -ENOMEM;
410
411                 local->hw_scan_req->ssids = req->ssids;
412                 local->hw_scan_req->n_ssids = req->n_ssids;
413                 ies = (u8 *)local->hw_scan_req +
414                         sizeof(*local->hw_scan_req) +
415                         req->n_channels * sizeof(req->channels[0]);
416                 local->hw_scan_req->ie = ies;
417
418                 local->hw_scan_band = 0;
419
420                 /*
421                  * After allocating local->hw_scan_req, we must
422                  * go through until ieee80211_prep_hw_scan(), so
423                  * anything that might be changed here and leave
424                  * this function early must not go after this
425                  * allocation.
426                  */
427         }
428
429         local->scan_req = req;
430         local->scan_sdata = sdata;
431
432         if (local->ops->hw_scan)
433                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
434         else
435                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
436
437         ieee80211_recalc_idle(local);
438
439         if (local->ops->hw_scan) {
440                 WARN_ON(!ieee80211_prep_hw_scan(local));
441                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
442         } else
443                 rc = ieee80211_start_sw_scan(local);
444
445         if (rc) {
446                 kfree(local->hw_scan_req);
447                 local->hw_scan_req = NULL;
448                 local->scanning = 0;
449
450                 ieee80211_recalc_idle(local);
451
452                 local->scan_req = NULL;
453                 local->scan_sdata = NULL;
454         }
455
456         return rc;
457 }
458
459 static unsigned long
460 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
461 {
462         /*
463          * TODO: channel switching also consumes quite some time,
464          * add that delay as well to get a better estimation
465          */
466         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
467                 return IEEE80211_PASSIVE_CHANNEL_TIME;
468         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
469 }
470
471 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
472                                           unsigned long *next_delay)
473 {
474         bool associated = false;
475         bool tx_empty = true;
476         bool bad_latency;
477         bool listen_int_exceeded;
478         unsigned long min_beacon_int = 0;
479         struct ieee80211_sub_if_data *sdata;
480         struct ieee80211_channel *next_chan;
481
482         /*
483          * check if at least one STA interface is associated,
484          * check if at least one STA interface has pending tx frames
485          * and grab the lowest used beacon interval
486          */
487         mutex_lock(&local->iflist_mtx);
488         list_for_each_entry(sdata, &local->interfaces, list) {
489                 if (!ieee80211_sdata_running(sdata))
490                         continue;
491
492                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
493                         if (sdata->u.mgd.associated) {
494                                 associated = true;
495
496                                 if (sdata->vif.bss_conf.beacon_int <
497                                     min_beacon_int || min_beacon_int == 0)
498                                         min_beacon_int =
499                                                 sdata->vif.bss_conf.beacon_int;
500
501                                 if (!qdisc_all_tx_empty(sdata->dev)) {
502                                         tx_empty = false;
503                                         break;
504                                 }
505                         }
506                 }
507         }
508         mutex_unlock(&local->iflist_mtx);
509
510         next_chan = local->scan_req->channels[local->scan_channel_idx];
511
512         if (ieee80211_cfg_on_oper_channel(local)) {
513                 /* We're currently on operating channel. */
514                 if (next_chan == local->oper_channel)
515                         /* We don't need to move off of operating channel. */
516                         local->next_scan_state = SCAN_SET_CHANNEL;
517                 else
518                         /*
519                          * We do need to leave operating channel, as next
520                          * scan is somewhere else.
521                          */
522                         local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
523         } else {
524                 /*
525                  * we're currently scanning a different channel, let's
526                  * see if we can scan another channel without interfering
527                  * with the current traffic situation.
528                  *
529                  * Since we don't know if the AP has pending frames for us
530                  * we can only check for our tx queues and use the current
531                  * pm_qos requirements for rx. Hence, if no tx traffic occurs
532                  * at all we will scan as many channels in a row as the pm_qos
533                  * latency allows us to. Additionally we also check for the
534                  * currently negotiated listen interval to prevent losing
535                  * frames unnecessarily.
536                  *
537                  * Otherwise switch back to the operating channel.
538                  */
539
540                 bad_latency = time_after(jiffies +
541                                 ieee80211_scan_get_channel_time(next_chan),
542                                 local->leave_oper_channel_time +
543                                 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
544
545                 listen_int_exceeded = time_after(jiffies +
546                                 ieee80211_scan_get_channel_time(next_chan),
547                                 local->leave_oper_channel_time +
548                                 usecs_to_jiffies(min_beacon_int * 1024) *
549                                 local->hw.conf.listen_interval);
550
551                 if (associated && ( !tx_empty || bad_latency ||
552                     listen_int_exceeded))
553                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
554                 else
555                         local->next_scan_state = SCAN_SET_CHANNEL;
556         }
557
558         *next_delay = 0;
559 }
560
561 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
562                                                     unsigned long *next_delay)
563 {
564         /* PS will already be in off-channel mode,
565          * we do that once at the beginning of scanning.
566          */
567         ieee80211_offchannel_stop_vifs(local, false);
568
569         /*
570          * What if the nullfunc frames didn't arrive?
571          */
572         drv_flush(local, false);
573         if (local->ops->flush)
574                 *next_delay = 0;
575         else
576                 *next_delay = HZ / 10;
577
578         /* remember when we left the operating channel */
579         local->leave_oper_channel_time = jiffies;
580
581         /* advance to the next channel to be scanned */
582         local->next_scan_state = SCAN_SET_CHANNEL;
583 }
584
585 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
586                                                     unsigned long *next_delay)
587 {
588         /* switch back to the operating channel */
589         local->scan_channel = NULL;
590         if (!ieee80211_cfg_on_oper_channel(local))
591                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
592
593         /*
594          * Re-enable vifs and beaconing.  Leave PS
595          * in off-channel state..will put that back
596          * on-channel at the end of scanning.
597          */
598         ieee80211_offchannel_return(local, true, false);
599
600         *next_delay = HZ / 5;
601         local->next_scan_state = SCAN_DECISION;
602 }
603
604 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
605                                              unsigned long *next_delay)
606 {
607         int skip;
608         struct ieee80211_channel *chan;
609
610         skip = 0;
611         chan = local->scan_req->channels[local->scan_channel_idx];
612
613         local->scan_channel = chan;
614
615         /* Only call hw-config if we really need to change channels. */
616         if (chan != local->hw.conf.channel)
617                 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
618                         skip = 1;
619
620         /* advance state machine to next channel/band */
621         local->scan_channel_idx++;
622
623         if (skip) {
624                 /* if we skip this channel return to the decision state */
625                 local->next_scan_state = SCAN_DECISION;
626                 return;
627         }
628
629         /*
630          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
631          * (which unfortunately doesn't say _why_ step a) is done,
632          * but it waits for the probe delay or until a frame is
633          * received - and the received frame would update the NAV).
634          * For now, we do not support waiting until a frame is
635          * received.
636          *
637          * In any case, it is not necessary for a passive scan.
638          */
639         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
640             !local->scan_req->n_ssids) {
641                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
642                 local->next_scan_state = SCAN_DECISION;
643                 return;
644         }
645
646         /* active scan, send probes */
647         *next_delay = IEEE80211_PROBE_DELAY;
648         local->next_scan_state = SCAN_SEND_PROBE;
649 }
650
651 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
652                                             unsigned long *next_delay)
653 {
654         int i;
655         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
656
657         for (i = 0; i < local->scan_req->n_ssids; i++)
658                 ieee80211_send_probe_req(
659                         sdata, NULL,
660                         local->scan_req->ssids[i].ssid,
661                         local->scan_req->ssids[i].ssid_len,
662                         local->scan_req->ie, local->scan_req->ie_len,
663                         false);
664
665         /*
666          * After sending probe requests, wait for probe responses
667          * on the channel.
668          */
669         *next_delay = IEEE80211_CHANNEL_TIME;
670         local->next_scan_state = SCAN_DECISION;
671 }
672
673 void ieee80211_scan_work(struct work_struct *work)
674 {
675         struct ieee80211_local *local =
676                 container_of(work, struct ieee80211_local, scan_work.work);
677         struct ieee80211_sub_if_data *sdata;
678         unsigned long next_delay = 0;
679         bool aborted, hw_scan;
680
681         mutex_lock(&local->mtx);
682
683         sdata = local->scan_sdata;
684
685         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
686                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
687                 goto out_complete;
688         }
689
690         if (!sdata || !local->scan_req)
691                 goto out;
692
693         if (local->scan_req && !local->scanning) {
694                 struct cfg80211_scan_request *req = local->scan_req;
695                 int rc;
696
697                 local->scan_req = NULL;
698                 local->scan_sdata = NULL;
699
700                 rc = __ieee80211_start_scan(sdata, req);
701                 if (rc) {
702                         /* need to complete scan in cfg80211 */
703                         local->scan_req = req;
704                         aborted = true;
705                         goto out_complete;
706                 } else
707                         goto out;
708         }
709
710         /*
711          * Avoid re-scheduling when the sdata is going away.
712          */
713         if (!ieee80211_sdata_running(sdata)) {
714                 aborted = true;
715                 goto out_complete;
716         }
717
718         /*
719          * as long as no delay is required advance immediately
720          * without scheduling a new work
721          */
722         do {
723                 if (!ieee80211_sdata_running(sdata)) {
724                         aborted = true;
725                         goto out_complete;
726                 }
727
728                 switch (local->next_scan_state) {
729                 case SCAN_DECISION:
730                         /* if no more bands/channels left, complete scan */
731                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
732                                 aborted = false;
733                                 goto out_complete;
734                         }
735                         ieee80211_scan_state_decision(local, &next_delay);
736                         break;
737                 case SCAN_SET_CHANNEL:
738                         ieee80211_scan_state_set_channel(local, &next_delay);
739                         break;
740                 case SCAN_SEND_PROBE:
741                         ieee80211_scan_state_send_probe(local, &next_delay);
742                         break;
743                 case SCAN_LEAVE_OPER_CHANNEL:
744                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
745                         break;
746                 case SCAN_ENTER_OPER_CHANNEL:
747                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
748                         break;
749                 }
750         } while (next_delay == 0);
751
752         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
753         goto out;
754
755 out_complete:
756         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
757         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
758 out:
759         mutex_unlock(&local->mtx);
760 }
761
762 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
763                            struct cfg80211_scan_request *req)
764 {
765         int res;
766
767         mutex_lock(&sdata->local->mtx);
768         res = __ieee80211_start_scan(sdata, req);
769         mutex_unlock(&sdata->local->mtx);
770
771         return res;
772 }
773
774 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
775                                     const u8 *ssid, u8 ssid_len,
776                                     struct ieee80211_channel *chan)
777 {
778         struct ieee80211_local *local = sdata->local;
779         int ret = -EBUSY;
780         enum ieee80211_band band;
781
782         mutex_lock(&local->mtx);
783
784         /* busy scanning */
785         if (local->scan_req)
786                 goto unlock;
787
788         /* fill internal scan request */
789         if (!chan) {
790                 int i, nchan = 0;
791
792                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
793                         if (!local->hw.wiphy->bands[band])
794                                 continue;
795                         for (i = 0;
796                              i < local->hw.wiphy->bands[band]->n_channels;
797                              i++) {
798                                 local->int_scan_req->channels[nchan] =
799                                     &local->hw.wiphy->bands[band]->channels[i];
800                                 nchan++;
801                         }
802                 }
803
804                 local->int_scan_req->n_channels = nchan;
805         } else {
806                 local->int_scan_req->channels[0] = chan;
807                 local->int_scan_req->n_channels = 1;
808         }
809
810         local->int_scan_req->ssids = &local->scan_ssid;
811         local->int_scan_req->n_ssids = 1;
812         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
813         local->int_scan_req->ssids[0].ssid_len = ssid_len;
814
815         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
816  unlock:
817         mutex_unlock(&local->mtx);
818         return ret;
819 }
820
821 /*
822  * Only call this function when a scan can't be queued -- under RTNL.
823  */
824 void ieee80211_scan_cancel(struct ieee80211_local *local)
825 {
826         /*
827          * We are canceling software scan, or deferred scan that was not
828          * yet really started (see __ieee80211_start_scan ).
829          *
830          * Regarding hardware scan:
831          * - we can not call  __ieee80211_scan_completed() as when
832          *   SCAN_HW_SCANNING bit is set this function change
833          *   local->hw_scan_req to operate on 5G band, what race with
834          *   driver which can use local->hw_scan_req
835          *
836          * - we can not cancel scan_work since driver can schedule it
837          *   by ieee80211_scan_completed(..., true) to finish scan
838          *
839          * Hence we only call the cancel_hw_scan() callback, but the low-level
840          * driver is still responsible for calling ieee80211_scan_completed()
841          * after the scan was completed/aborted.
842          */
843
844         mutex_lock(&local->mtx);
845         if (!local->scan_req)
846                 goto out;
847
848         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
849                 if (local->ops->cancel_hw_scan)
850                         drv_cancel_hw_scan(local, local->scan_sdata);
851                 goto out;
852         }
853
854         /*
855          * If the work is currently running, it must be blocked on
856          * the mutex, but we'll set scan_sdata = NULL and it'll
857          * simply exit once it acquires the mutex.
858          */
859         cancel_delayed_work(&local->scan_work);
860         /* and clean up */
861         __ieee80211_scan_completed(&local->hw, true, false);
862 out:
863         mutex_unlock(&local->mtx);
864 }
865
866 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
867                                        struct cfg80211_sched_scan_request *req)
868 {
869         struct ieee80211_local *local = sdata->local;
870         int ret, i;
871
872         mutex_lock(&sdata->local->mtx);
873
874         if (local->sched_scanning) {
875                 ret = -EBUSY;
876                 goto out;
877         }
878
879         if (!local->ops->sched_scan_start) {
880                 ret = -ENOTSUPP;
881                 goto out;
882         }
883
884         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
885                 local->sched_scan_ies.ie[i] = kzalloc(2 +
886                                                       IEEE80211_MAX_SSID_LEN +
887                                                       local->scan_ies_len +
888                                                       req->ie_len,
889                                                       GFP_KERNEL);
890                 if (!local->sched_scan_ies.ie[i]) {
891                         ret = -ENOMEM;
892                         goto out_free;
893                 }
894
895                 local->sched_scan_ies.len[i] =
896                         ieee80211_build_preq_ies(local,
897                                                  local->sched_scan_ies.ie[i],
898                                                  req->ie, req->ie_len, i,
899                                                  (u32) -1, 0);
900         }
901
902         ret = drv_sched_scan_start(local, sdata, req,
903                                    &local->sched_scan_ies);
904         if (ret == 0) {
905                 local->sched_scanning = true;
906                 goto out;
907         }
908
909 out_free:
910         while (i > 0)
911                 kfree(local->sched_scan_ies.ie[--i]);
912 out:
913         mutex_unlock(&sdata->local->mtx);
914         return ret;
915 }
916
917 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
918 {
919         struct ieee80211_local *local = sdata->local;
920         int ret = 0, i;
921
922         mutex_lock(&sdata->local->mtx);
923
924         if (!local->ops->sched_scan_stop) {
925                 ret = -ENOTSUPP;
926                 goto out;
927         }
928
929         if (local->sched_scanning) {
930                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
931                         kfree(local->sched_scan_ies.ie[i]);
932
933                 drv_sched_scan_stop(local, sdata);
934                 local->sched_scanning = false;
935         }
936 out:
937         mutex_unlock(&sdata->local->mtx);
938
939         return ret;
940 }
941
942 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
943 {
944         struct ieee80211_local *local = hw_to_local(hw);
945
946         trace_api_sched_scan_results(local);
947
948         cfg80211_sched_scan_results(hw->wiphy);
949 }
950 EXPORT_SYMBOL(ieee80211_sched_scan_results);
951
952 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
953 {
954         struct ieee80211_local *local =
955                 container_of(work, struct ieee80211_local,
956                              sched_scan_stopped_work);
957         int i;
958
959         mutex_lock(&local->mtx);
960
961         if (!local->sched_scanning) {
962                 mutex_unlock(&local->mtx);
963                 return;
964         }
965
966         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
967                 kfree(local->sched_scan_ies.ie[i]);
968
969         local->sched_scanning = false;
970
971         mutex_unlock(&local->mtx);
972
973         cfg80211_sched_scan_stopped(local->hw.wiphy);
974 }
975
976 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
977 {
978         struct ieee80211_local *local = hw_to_local(hw);
979
980         trace_api_sched_scan_stopped(local);
981
982         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
983 }
984 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);