mac80211: make key locking clearer
[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 <linux/slab.h>
19 #include <net/sch_generic.h>
20 #include <linux/slab.h>
21 #include <net/mac80211.h>
22
23 #include "ieee80211_i.h"
24 #include "driver-ops.h"
25 #include "mesh.h"
26
27 #define IEEE80211_PROBE_DELAY (HZ / 33)
28 #define IEEE80211_CHANNEL_TIME (HZ / 33)
29 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
30
31 struct ieee80211_bss *
32 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
33                      u8 *ssid, u8 ssid_len)
34 {
35         struct cfg80211_bss *cbss;
36
37         cbss = cfg80211_get_bss(local->hw.wiphy,
38                                 ieee80211_get_channel(local->hw.wiphy, freq),
39                                 bssid, ssid, ssid_len, 0, 0);
40         if (!cbss)
41                 return NULL;
42         return (void *)cbss->priv;
43 }
44
45 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
46 {
47         struct ieee80211_bss *bss = (void *)cbss->priv;
48
49         kfree(bss_mesh_id(bss));
50         kfree(bss_mesh_cfg(bss));
51 }
52
53 void ieee80211_rx_bss_put(struct ieee80211_local *local,
54                           struct ieee80211_bss *bss)
55 {
56         if (!bss)
57                 return;
58         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
59 }
60
61 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
62 {
63         u8 qos_info;
64
65         if (elems->wmm_info && elems->wmm_info_len == 7
66             && elems->wmm_info[5] == 1)
67                 qos_info = elems->wmm_info[6];
68         else if (elems->wmm_param && elems->wmm_param_len == 24
69                  && elems->wmm_param[5] == 1)
70                 qos_info = elems->wmm_param[6];
71         else
72                 /* no valid wmm information or parameter element found */
73                 return false;
74
75         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
76 }
77
78 struct ieee80211_bss *
79 ieee80211_bss_info_update(struct ieee80211_local *local,
80                           struct ieee80211_rx_status *rx_status,
81                           struct ieee80211_mgmt *mgmt,
82                           size_t len,
83                           struct ieee802_11_elems *elems,
84                           struct ieee80211_channel *channel,
85                           bool beacon)
86 {
87         struct cfg80211_bss *cbss;
88         struct ieee80211_bss *bss;
89         int clen, srlen;
90         s32 signal = 0;
91
92         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
93                 signal = rx_status->signal * 100;
94         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
95                 signal = (rx_status->signal * 100) / local->hw.max_signal;
96
97         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
98                                          mgmt, len, signal, GFP_ATOMIC);
99
100         if (!cbss)
101                 return NULL;
102
103         cbss->free_priv = ieee80211_rx_bss_free;
104         bss = (void *)cbss->priv;
105
106         /* save the ERP value so that it is available at association time */
107         if (elems->erp_info && elems->erp_info_len >= 1) {
108                 bss->erp_value = elems->erp_info[0];
109                 bss->has_erp_value = 1;
110         }
111
112         if (elems->tim) {
113                 struct ieee80211_tim_ie *tim_ie =
114                         (struct ieee80211_tim_ie *)elems->tim;
115                 bss->dtim_period = tim_ie->dtim_period;
116         }
117
118         /* If the beacon had no TIM IE, or it was invalid, use 1 */
119         if (beacon && !bss->dtim_period)
120                 bss->dtim_period = 1;
121
122         /* replace old supported rates if we get new values */
123         srlen = 0;
124         if (elems->supp_rates) {
125                 clen = IEEE80211_MAX_SUPP_RATES;
126                 if (clen > elems->supp_rates_len)
127                         clen = elems->supp_rates_len;
128                 memcpy(bss->supp_rates, elems->supp_rates, clen);
129                 srlen += clen;
130         }
131         if (elems->ext_supp_rates) {
132                 clen = IEEE80211_MAX_SUPP_RATES - srlen;
133                 if (clen > elems->ext_supp_rates_len)
134                         clen = elems->ext_supp_rates_len;
135                 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
136                 srlen += clen;
137         }
138         if (srlen)
139                 bss->supp_rates_len = srlen;
140
141         bss->wmm_used = elems->wmm_param || elems->wmm_info;
142         bss->uapsd_supported = is_uapsd_supported(elems);
143
144         if (!beacon)
145                 bss->last_probe_resp = jiffies;
146
147         return bss;
148 }
149
150 ieee80211_rx_result
151 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
152 {
153         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
154         struct ieee80211_mgmt *mgmt;
155         struct ieee80211_bss *bss;
156         u8 *elements;
157         struct ieee80211_channel *channel;
158         size_t baselen;
159         int freq;
160         __le16 fc;
161         bool presp, beacon = false;
162         struct ieee802_11_elems elems;
163
164         if (skb->len < 2)
165                 return RX_DROP_UNUSABLE;
166
167         mgmt = (struct ieee80211_mgmt *) skb->data;
168         fc = mgmt->frame_control;
169
170         if (ieee80211_is_ctl(fc))
171                 return RX_CONTINUE;
172
173         if (skb->len < 24)
174                 return RX_CONTINUE;
175
176         presp = ieee80211_is_probe_resp(fc);
177         if (presp) {
178                 /* ignore ProbeResp to foreign address */
179                 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
180                         return RX_DROP_MONITOR;
181
182                 presp = true;
183                 elements = mgmt->u.probe_resp.variable;
184                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
185         } else {
186                 beacon = ieee80211_is_beacon(fc);
187                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
188                 elements = mgmt->u.beacon.variable;
189         }
190
191         if (!presp && !beacon)
192                 return RX_CONTINUE;
193
194         if (baselen > skb->len)
195                 return RX_DROP_MONITOR;
196
197         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
198
199         if (elems.ds_params && elems.ds_params_len == 1)
200                 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
201                                                       rx_status->band);
202         else
203                 freq = rx_status->freq;
204
205         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
206
207         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
208                 return RX_DROP_MONITOR;
209
210         bss = ieee80211_bss_info_update(sdata->local, rx_status,
211                                         mgmt, skb->len, &elems,
212                                         channel, beacon);
213         if (bss)
214                 ieee80211_rx_bss_put(sdata->local, bss);
215
216         /* If we are on-operating-channel, and this packet is for the
217          * current channel, pass the pkt on up the stack so that
218          * the rest of the stack can make use of it.
219          */
220         if (ieee80211_cfg_on_oper_channel(sdata->local)
221             && (channel == sdata->local->oper_channel))
222                 return RX_CONTINUE;
223
224         dev_kfree_skb(skb);
225         return RX_QUEUED;
226 }
227
228 /* return false if no more work */
229 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
230 {
231         struct cfg80211_scan_request *req = local->scan_req;
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, (u32) -1,
256                                          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
664         /*
665          * After sending probe requests, wait for probe responses
666          * on the channel.
667          */
668         *next_delay = IEEE80211_CHANNEL_TIME;
669         local->next_scan_state = SCAN_DECISION;
670 }
671
672 void ieee80211_scan_work(struct work_struct *work)
673 {
674         struct ieee80211_local *local =
675                 container_of(work, struct ieee80211_local, scan_work.work);
676         struct ieee80211_sub_if_data *sdata;
677         unsigned long next_delay = 0;
678         bool aborted, hw_scan;
679
680         mutex_lock(&local->mtx);
681
682         sdata = local->scan_sdata;
683
684         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
685                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
686                 goto out_complete;
687         }
688
689         if (!sdata || !local->scan_req)
690                 goto out;
691
692         if (local->scan_req && !local->scanning) {
693                 struct cfg80211_scan_request *req = local->scan_req;
694                 int rc;
695
696                 local->scan_req = NULL;
697                 local->scan_sdata = NULL;
698
699                 rc = __ieee80211_start_scan(sdata, req);
700                 if (rc) {
701                         /* need to complete scan in cfg80211 */
702                         local->scan_req = req;
703                         aborted = true;
704                         goto out_complete;
705                 } else
706                         goto out;
707         }
708
709         /*
710          * Avoid re-scheduling when the sdata is going away.
711          */
712         if (!ieee80211_sdata_running(sdata)) {
713                 aborted = true;
714                 goto out_complete;
715         }
716
717         /*
718          * as long as no delay is required advance immediately
719          * without scheduling a new work
720          */
721         do {
722                 switch (local->next_scan_state) {
723                 case SCAN_DECISION:
724                         /* if no more bands/channels left, complete scan */
725                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
726                                 aborted = false;
727                                 goto out_complete;
728                         }
729                         ieee80211_scan_state_decision(local, &next_delay);
730                         break;
731                 case SCAN_SET_CHANNEL:
732                         ieee80211_scan_state_set_channel(local, &next_delay);
733                         break;
734                 case SCAN_SEND_PROBE:
735                         ieee80211_scan_state_send_probe(local, &next_delay);
736                         break;
737                 case SCAN_LEAVE_OPER_CHANNEL:
738                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
739                         break;
740                 case SCAN_ENTER_OPER_CHANNEL:
741                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
742                         break;
743                 }
744         } while (next_delay == 0);
745
746         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
747         goto out;
748
749 out_complete:
750         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
751         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
752 out:
753         mutex_unlock(&local->mtx);
754 }
755
756 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
757                            struct cfg80211_scan_request *req)
758 {
759         int res;
760
761         mutex_lock(&sdata->local->mtx);
762         res = __ieee80211_start_scan(sdata, req);
763         mutex_unlock(&sdata->local->mtx);
764
765         return res;
766 }
767
768 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
769                                     const u8 *ssid, u8 ssid_len,
770                                     struct ieee80211_channel *chan)
771 {
772         struct ieee80211_local *local = sdata->local;
773         int ret = -EBUSY;
774         enum ieee80211_band band;
775
776         mutex_lock(&local->mtx);
777
778         /* busy scanning */
779         if (local->scan_req)
780                 goto unlock;
781
782         /* fill internal scan request */
783         if (!chan) {
784                 int i, nchan = 0;
785
786                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
787                         if (!local->hw.wiphy->bands[band])
788                                 continue;
789                         for (i = 0;
790                              i < local->hw.wiphy->bands[band]->n_channels;
791                              i++) {
792                                 local->int_scan_req->channels[nchan] =
793                                     &local->hw.wiphy->bands[band]->channels[i];
794                                 nchan++;
795                         }
796                 }
797
798                 local->int_scan_req->n_channels = nchan;
799         } else {
800                 local->int_scan_req->channels[0] = chan;
801                 local->int_scan_req->n_channels = 1;
802         }
803
804         local->int_scan_req->ssids = &local->scan_ssid;
805         local->int_scan_req->n_ssids = 1;
806         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
807         local->int_scan_req->ssids[0].ssid_len = ssid_len;
808
809         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
810  unlock:
811         mutex_unlock(&local->mtx);
812         return ret;
813 }
814
815 /*
816  * Only call this function when a scan can't be queued -- under RTNL.
817  */
818 void ieee80211_scan_cancel(struct ieee80211_local *local)
819 {
820         bool abortscan;
821
822         /*
823          * We are only canceling software scan, or deferred scan that was not
824          * yet really started (see __ieee80211_start_scan ).
825          *
826          * Regarding hardware scan:
827          * - we can not call  __ieee80211_scan_completed() as when
828          *   SCAN_HW_SCANNING bit is set this function change
829          *   local->hw_scan_req to operate on 5G band, what race with
830          *   driver which can use local->hw_scan_req
831          *
832          * - we can not cancel scan_work since driver can schedule it
833          *   by ieee80211_scan_completed(..., true) to finish scan
834          *
835          * Hence low lever driver is responsible for canceling HW scan.
836          */
837
838         mutex_lock(&local->mtx);
839         abortscan = local->scan_req && !test_bit(SCAN_HW_SCANNING, &local->scanning);
840         if (abortscan) {
841                 /*
842                  * The scan is canceled, but stop work from being pending.
843                  *
844                  * If the work is currently running, it must be blocked on
845                  * the mutex, but we'll set scan_sdata = NULL and it'll
846                  * simply exit once it acquires the mutex.
847                  */
848                 cancel_delayed_work(&local->scan_work);
849                 /* and clean up */
850                 __ieee80211_scan_completed(&local->hw, true, false);
851         }
852         mutex_unlock(&local->mtx);
853 }
854
855 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
856                                        struct cfg80211_sched_scan_request *req)
857 {
858         struct ieee80211_local *local = sdata->local;
859         int ret, i;
860
861         mutex_lock(&sdata->local->mtx);
862
863         if (local->sched_scanning) {
864                 ret = -EBUSY;
865                 goto out;
866         }
867
868         if (!local->ops->sched_scan_start) {
869                 ret = -ENOTSUPP;
870                 goto out;
871         }
872
873         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
874                 local->sched_scan_ies.ie[i] = kzalloc(2 +
875                                                       IEEE80211_MAX_SSID_LEN +
876                                                       local->scan_ies_len,
877                                                       GFP_KERNEL);
878                 if (!local->sched_scan_ies.ie[i]) {
879                         ret = -ENOMEM;
880                         goto out_free;
881                 }
882
883                 local->sched_scan_ies.len[i] =
884                         ieee80211_build_preq_ies(local,
885                                                  local->sched_scan_ies.ie[i],
886                                                  req->ie, req->ie_len, i,
887                                                  (u32) -1, 0);
888         }
889
890         ret = drv_sched_scan_start(local, sdata, req,
891                                    &local->sched_scan_ies);
892         if (ret == 0) {
893                 local->sched_scanning = true;
894                 goto out;
895         }
896
897 out_free:
898         while (i > 0)
899                 kfree(local->sched_scan_ies.ie[--i]);
900 out:
901         mutex_unlock(&sdata->local->mtx);
902         return ret;
903 }
904
905 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata,
906                                       bool driver_initiated)
907 {
908         struct ieee80211_local *local = sdata->local;
909         int ret = 0, i;
910
911         mutex_lock(&sdata->local->mtx);
912
913         if (!local->ops->sched_scan_stop) {
914                 ret = -ENOTSUPP;
915                 goto out;
916         }
917
918         if (local->sched_scanning) {
919                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
920                         kfree(local->sched_scan_ies.ie[i]);
921
922                 if (!driver_initiated)
923                         drv_sched_scan_stop(local, sdata);
924                 local->sched_scanning = false;
925         }
926
927 out:
928         mutex_unlock(&sdata->local->mtx);
929
930         return ret;
931 }
932
933 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
934 {
935         struct ieee80211_local *local = hw_to_local(hw);
936
937         trace_api_sched_scan_results(local);
938
939         cfg80211_sched_scan_results(hw->wiphy);
940 }
941 EXPORT_SYMBOL(ieee80211_sched_scan_results);
942
943 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
944 {
945         struct ieee80211_local *local = hw_to_local(hw);
946
947         trace_api_sched_scan_stopped(local);
948
949         cfg80211_sched_scan_stopped(hw->wiphy);
950 }
951 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);