33cd169013781321a813e10ebfb474c9595bd857
[~shefty/rdma-dev.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 / 8)
31
32 struct ieee80211_bss *
33 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
34                      u8 *ssid, u8 ssid_len)
35 {
36         struct cfg80211_bss *cbss;
37
38         cbss = cfg80211_get_bss(local->hw.wiphy,
39                                 ieee80211_get_channel(local->hw.wiphy, freq),
40                                 bssid, ssid, ssid_len, 0, 0);
41         if (!cbss)
42                 return NULL;
43         return (void *)cbss->priv;
44 }
45
46 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
47 {
48         struct ieee80211_bss *bss = (void *)cbss->priv;
49
50         kfree(bss_mesh_id(bss));
51         kfree(bss_mesh_cfg(bss));
52 }
53
54 void ieee80211_rx_bss_put(struct ieee80211_local *local,
55                           struct ieee80211_bss *bss)
56 {
57         if (!bss)
58                 return;
59         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
60 }
61
62 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
63 {
64         u8 qos_info;
65
66         if (elems->wmm_info && elems->wmm_info_len == 7
67             && elems->wmm_info[5] == 1)
68                 qos_info = elems->wmm_info[6];
69         else if (elems->wmm_param && elems->wmm_param_len == 24
70                  && elems->wmm_param[5] == 1)
71                 qos_info = elems->wmm_param[6];
72         else
73                 /* no valid wmm information or parameter element found */
74                 return false;
75
76         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
77 }
78
79 struct ieee80211_bss *
80 ieee80211_bss_info_update(struct ieee80211_local *local,
81                           struct ieee80211_rx_status *rx_status,
82                           struct ieee80211_mgmt *mgmt,
83                           size_t len,
84                           struct ieee802_11_elems *elems,
85                           struct ieee80211_channel *channel,
86                           bool beacon)
87 {
88         struct cfg80211_bss *cbss;
89         struct ieee80211_bss *bss;
90         int clen, srlen;
91         s32 signal = 0;
92
93         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
94                 signal = rx_status->signal * 100;
95         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
96                 signal = (rx_status->signal * 100) / local->hw.max_signal;
97
98         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
99                                          mgmt, len, signal, GFP_ATOMIC);
100
101         if (!cbss)
102                 return NULL;
103
104         cbss->free_priv = ieee80211_rx_bss_free;
105         bss = (void *)cbss->priv;
106
107         if (elems->parse_error) {
108                 if (beacon)
109                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
110                 else
111                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
112         } else {
113                 if (beacon)
114                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
115                 else
116                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
117         }
118
119         /* save the ERP value so that it is available at association time */
120         if (elems->erp_info && elems->erp_info_len >= 1 &&
121                         (!elems->parse_error ||
122                          !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
123                 bss->erp_value = elems->erp_info[0];
124                 bss->has_erp_value = true;
125                 if (!elems->parse_error)
126                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
127         }
128
129         if (elems->tim && (!elems->parse_error ||
130                            !(bss->valid_data & IEEE80211_BSS_VALID_DTIM))) {
131                 struct ieee80211_tim_ie *tim_ie =
132                         (struct ieee80211_tim_ie *)elems->tim;
133                 bss->dtim_period = tim_ie->dtim_period;
134                 if (!elems->parse_error)
135                                 bss->valid_data |= IEEE80211_BSS_VALID_DTIM;
136         }
137
138         /* If the beacon had no TIM IE, or it was invalid, use 1 */
139         if (beacon && !bss->dtim_period)
140                 bss->dtim_period = 1;
141
142         /* replace old supported rates if we get new values */
143         if (!elems->parse_error ||
144             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
145                 srlen = 0;
146                 if (elems->supp_rates) {
147                         clen = IEEE80211_MAX_SUPP_RATES;
148                         if (clen > elems->supp_rates_len)
149                                 clen = elems->supp_rates_len;
150                         memcpy(bss->supp_rates, elems->supp_rates, clen);
151                         srlen += clen;
152                 }
153                 if (elems->ext_supp_rates) {
154                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
155                         if (clen > elems->ext_supp_rates_len)
156                                 clen = elems->ext_supp_rates_len;
157                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
158                                clen);
159                         srlen += clen;
160                 }
161                 if (srlen) {
162                         bss->supp_rates_len = srlen;
163                         if (!elems->parse_error)
164                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
165                 }
166         }
167
168         if (!elems->parse_error ||
169             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
170                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
171                 bss->uapsd_supported = is_uapsd_supported(elems);
172                 if (!elems->parse_error)
173                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
174         }
175
176         if (!beacon)
177                 bss->last_probe_resp = jiffies;
178
179         return bss;
180 }
181
182 ieee80211_rx_result
183 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
184 {
185         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
186         struct ieee80211_mgmt *mgmt;
187         struct ieee80211_bss *bss;
188         u8 *elements;
189         struct ieee80211_channel *channel;
190         size_t baselen;
191         int freq;
192         __le16 fc;
193         bool presp, beacon = false;
194         struct ieee802_11_elems elems;
195
196         if (skb->len < 2)
197                 return RX_DROP_UNUSABLE;
198
199         mgmt = (struct ieee80211_mgmt *) skb->data;
200         fc = mgmt->frame_control;
201
202         if (ieee80211_is_ctl(fc))
203                 return RX_CONTINUE;
204
205         if (skb->len < 24)
206                 return RX_CONTINUE;
207
208         presp = ieee80211_is_probe_resp(fc);
209         if (presp) {
210                 /* ignore ProbeResp to foreign address */
211                 if (compare_ether_addr(mgmt->da, sdata->vif.addr))
212                         return RX_DROP_MONITOR;
213
214                 presp = true;
215                 elements = mgmt->u.probe_resp.variable;
216                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
217         } else {
218                 beacon = ieee80211_is_beacon(fc);
219                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
220                 elements = mgmt->u.beacon.variable;
221         }
222
223         if (!presp && !beacon)
224                 return RX_CONTINUE;
225
226         if (baselen > skb->len)
227                 return RX_DROP_MONITOR;
228
229         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
230
231         if (elems.ds_params && elems.ds_params_len == 1)
232                 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
233                                                       rx_status->band);
234         else
235                 freq = rx_status->freq;
236
237         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
238
239         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
240                 return RX_DROP_MONITOR;
241
242         bss = ieee80211_bss_info_update(sdata->local, rx_status,
243                                         mgmt, skb->len, &elems,
244                                         channel, beacon);
245         if (bss)
246                 ieee80211_rx_bss_put(sdata->local, bss);
247
248         if (channel == sdata->local->oper_channel)
249                 return RX_CONTINUE;
250
251         dev_kfree_skb(skb);
252         return RX_QUEUED;
253 }
254
255 /* return false if no more work */
256 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
257 {
258         struct cfg80211_scan_request *req = local->scan_req;
259         enum ieee80211_band band;
260         int i, ielen, n_chans;
261
262         do {
263                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
264                         return false;
265
266                 band = local->hw_scan_band;
267                 n_chans = 0;
268                 for (i = 0; i < req->n_channels; i++) {
269                         if (req->channels[i]->band == band) {
270                                 local->hw_scan_req->channels[n_chans] =
271                                                         req->channels[i];
272                                 n_chans++;
273                         }
274                 }
275
276                 local->hw_scan_band++;
277         } while (!n_chans);
278
279         local->hw_scan_req->n_channels = n_chans;
280
281         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
282                                          req->ie, req->ie_len, band,
283                                          req->rates[band], 0);
284         local->hw_scan_req->ie_len = ielen;
285         local->hw_scan_req->no_cck = req->no_cck;
286
287         return true;
288 }
289
290 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
291                                        bool was_hw_scan)
292 {
293         struct ieee80211_local *local = hw_to_local(hw);
294
295         lockdep_assert_held(&local->mtx);
296
297         /*
298          * It's ok to abort a not-yet-running scan (that
299          * we have one at all will be verified by checking
300          * local->scan_req next), but not to complete it
301          * successfully.
302          */
303         if (WARN_ON(!local->scanning && !aborted))
304                 aborted = true;
305
306         if (WARN_ON(!local->scan_req))
307                 return;
308
309         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
310                 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
311                 if (rc == 0)
312                         return;
313         }
314
315         kfree(local->hw_scan_req);
316         local->hw_scan_req = NULL;
317
318         if (local->scan_req != local->int_scan_req)
319                 cfg80211_scan_done(local->scan_req, aborted);
320         local->scan_req = NULL;
321         local->scan_sdata = NULL;
322
323         local->scanning = 0;
324         local->scan_channel = NULL;
325
326         /* Set power back to normal operating levels. */
327         ieee80211_hw_config(local, 0);
328
329         if (!was_hw_scan) {
330                 ieee80211_configure_filter(local);
331                 drv_sw_scan_complete(local);
332                 ieee80211_offchannel_return(local, true);
333         }
334
335         ieee80211_recalc_idle(local);
336
337         ieee80211_mlme_notify_scan_completed(local);
338         ieee80211_ibss_notify_scan_completed(local);
339         ieee80211_mesh_notify_scan_completed(local);
340         ieee80211_queue_work(&local->hw, &local->work_work);
341 }
342
343 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
344 {
345         struct ieee80211_local *local = hw_to_local(hw);
346
347         trace_api_scan_completed(local, aborted);
348
349         set_bit(SCAN_COMPLETED, &local->scanning);
350         if (aborted)
351                 set_bit(SCAN_ABORTED, &local->scanning);
352         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
353 }
354 EXPORT_SYMBOL(ieee80211_scan_completed);
355
356 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
357 {
358         /*
359          * Hardware/driver doesn't support hw_scan, so use software
360          * scanning instead. First send a nullfunc frame with power save
361          * bit on so that AP will buffer the frames for us while we are not
362          * listening, then send probe requests to each channel and wait for
363          * the responses. After all channels are scanned, tune back to the
364          * original channel and send a nullfunc frame with power save bit
365          * off to trigger the AP to send us all the buffered frames.
366          *
367          * Note that while local->sw_scanning is true everything else but
368          * nullfunc frames and probe requests will be dropped in
369          * ieee80211_tx_h_check_assoc().
370          */
371         drv_sw_scan_start(local);
372
373         local->leave_oper_channel_time = 0;
374         local->next_scan_state = SCAN_DECISION;
375         local->scan_channel_idx = 0;
376
377         ieee80211_offchannel_stop_vifs(local, true);
378
379         ieee80211_configure_filter(local);
380
381         /* We need to set power level at maximum rate for scanning. */
382         ieee80211_hw_config(local, 0);
383
384         ieee80211_queue_delayed_work(&local->hw,
385                                      &local->scan_work, 0);
386
387         return 0;
388 }
389
390
391 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
392                                   struct cfg80211_scan_request *req)
393 {
394         struct ieee80211_local *local = sdata->local;
395         int rc;
396
397         lockdep_assert_held(&local->mtx);
398
399         if (local->scan_req)
400                 return -EBUSY;
401
402         if (!list_empty(&local->work_list)) {
403                 /* wait for the work to finish/time out */
404                 local->scan_req = req;
405                 local->scan_sdata = sdata;
406                 return 0;
407         }
408
409         if (local->ops->hw_scan) {
410                 u8 *ies;
411
412                 local->hw_scan_req = kmalloc(
413                                 sizeof(*local->hw_scan_req) +
414                                 req->n_channels * sizeof(req->channels[0]) +
415                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
416                                 req->ie_len, GFP_KERNEL);
417                 if (!local->hw_scan_req)
418                         return -ENOMEM;
419
420                 local->hw_scan_req->ssids = req->ssids;
421                 local->hw_scan_req->n_ssids = req->n_ssids;
422                 ies = (u8 *)local->hw_scan_req +
423                         sizeof(*local->hw_scan_req) +
424                         req->n_channels * sizeof(req->channels[0]);
425                 local->hw_scan_req->ie = ies;
426
427                 local->hw_scan_band = 0;
428
429                 /*
430                  * After allocating local->hw_scan_req, we must
431                  * go through until ieee80211_prep_hw_scan(), so
432                  * anything that might be changed here and leave
433                  * this function early must not go after this
434                  * allocation.
435                  */
436         }
437
438         local->scan_req = req;
439         local->scan_sdata = sdata;
440
441         if (local->ops->hw_scan)
442                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
443         else
444                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
445
446         ieee80211_recalc_idle(local);
447
448         if (local->ops->hw_scan) {
449                 WARN_ON(!ieee80211_prep_hw_scan(local));
450                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
451         } else
452                 rc = ieee80211_start_sw_scan(local);
453
454         if (rc) {
455                 kfree(local->hw_scan_req);
456                 local->hw_scan_req = NULL;
457                 local->scanning = 0;
458
459                 ieee80211_recalc_idle(local);
460
461                 local->scan_req = NULL;
462                 local->scan_sdata = NULL;
463         }
464
465         return rc;
466 }
467
468 static unsigned long
469 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
470 {
471         /*
472          * TODO: channel switching also consumes quite some time,
473          * add that delay as well to get a better estimation
474          */
475         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
476                 return IEEE80211_PASSIVE_CHANNEL_TIME;
477         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
478 }
479
480 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
481                                           unsigned long *next_delay)
482 {
483         bool associated = false;
484         bool tx_empty = true;
485         bool bad_latency;
486         bool listen_int_exceeded;
487         unsigned long min_beacon_int = 0;
488         struct ieee80211_sub_if_data *sdata;
489         struct ieee80211_channel *next_chan;
490
491         /*
492          * check if at least one STA interface is associated,
493          * check if at least one STA interface has pending tx frames
494          * and grab the lowest used beacon interval
495          */
496         mutex_lock(&local->iflist_mtx);
497         list_for_each_entry(sdata, &local->interfaces, list) {
498                 if (!ieee80211_sdata_running(sdata))
499                         continue;
500
501                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
502                         if (sdata->u.mgd.associated) {
503                                 associated = true;
504
505                                 if (sdata->vif.bss_conf.beacon_int <
506                                     min_beacon_int || min_beacon_int == 0)
507                                         min_beacon_int =
508                                                 sdata->vif.bss_conf.beacon_int;
509
510                                 if (!qdisc_all_tx_empty(sdata->dev)) {
511                                         tx_empty = false;
512                                         break;
513                                 }
514                         }
515                 }
516         }
517         mutex_unlock(&local->iflist_mtx);
518
519         next_chan = local->scan_req->channels[local->scan_channel_idx];
520
521         /*
522          * we're currently scanning a different channel, let's
523          * see if we can scan another channel without interfering
524          * with the current traffic situation.
525          *
526          * Since we don't know if the AP has pending frames for us
527          * we can only check for our tx queues and use the current
528          * pm_qos requirements for rx. Hence, if no tx traffic occurs
529          * at all we will scan as many channels in a row as the pm_qos
530          * latency allows us to. Additionally we also check for the
531          * currently negotiated listen interval to prevent losing
532          * frames unnecessarily.
533          *
534          * Otherwise switch back to the operating channel.
535          */
536
537         bad_latency = time_after(jiffies +
538                         ieee80211_scan_get_channel_time(next_chan),
539                         local->leave_oper_channel_time +
540                         usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
541
542         listen_int_exceeded = time_after(jiffies +
543                         ieee80211_scan_get_channel_time(next_chan),
544                         local->leave_oper_channel_time +
545                         usecs_to_jiffies(min_beacon_int * 1024) *
546                         local->hw.conf.listen_interval);
547
548         if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
549                 local->next_scan_state = SCAN_SUSPEND;
550         else
551                 local->next_scan_state = SCAN_SET_CHANNEL;
552
553         *next_delay = 0;
554 }
555
556 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
557                                              unsigned long *next_delay)
558 {
559         int skip;
560         struct ieee80211_channel *chan;
561
562         skip = 0;
563         chan = local->scan_req->channels[local->scan_channel_idx];
564
565         local->scan_channel = chan;
566
567         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
568                 skip = 1;
569
570         /* advance state machine to next channel/band */
571         local->scan_channel_idx++;
572
573         if (skip) {
574                 /* if we skip this channel return to the decision state */
575                 local->next_scan_state = SCAN_DECISION;
576                 return;
577         }
578
579         /*
580          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
581          * (which unfortunately doesn't say _why_ step a) is done,
582          * but it waits for the probe delay or until a frame is
583          * received - and the received frame would update the NAV).
584          * For now, we do not support waiting until a frame is
585          * received.
586          *
587          * In any case, it is not necessary for a passive scan.
588          */
589         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
590             !local->scan_req->n_ssids) {
591                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
592                 local->next_scan_state = SCAN_DECISION;
593                 return;
594         }
595
596         /* active scan, send probes */
597         *next_delay = IEEE80211_PROBE_DELAY;
598         local->next_scan_state = SCAN_SEND_PROBE;
599 }
600
601 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
602                                             unsigned long *next_delay)
603 {
604         int i;
605         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
606         enum ieee80211_band band = local->hw.conf.channel->band;
607
608         for (i = 0; i < local->scan_req->n_ssids; i++)
609                 ieee80211_send_probe_req(
610                         sdata, NULL,
611                         local->scan_req->ssids[i].ssid,
612                         local->scan_req->ssids[i].ssid_len,
613                         local->scan_req->ie, local->scan_req->ie_len,
614                         local->scan_req->rates[band], false,
615                         local->scan_req->no_cck);
616
617         /*
618          * After sending probe requests, wait for probe responses
619          * on the channel.
620          */
621         *next_delay = IEEE80211_CHANNEL_TIME;
622         local->next_scan_state = SCAN_DECISION;
623 }
624
625 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
626                                          unsigned long *next_delay)
627 {
628         /* switch back to the operating channel */
629         local->scan_channel = NULL;
630         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
631
632         /*
633          * Re-enable vifs and beaconing.  Leave PS
634          * in off-channel state..will put that back
635          * on-channel at the end of scanning.
636          */
637         ieee80211_offchannel_return(local, false);
638
639         *next_delay = HZ / 5;
640         /* afterwards, resume scan & go to next channel */
641         local->next_scan_state = SCAN_RESUME;
642 }
643
644 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
645                                         unsigned long *next_delay)
646 {
647         /* PS already is in off-channel mode */
648         ieee80211_offchannel_stop_vifs(local, false);
649
650         if (local->ops->flush) {
651                 drv_flush(local, false);
652                 *next_delay = 0;
653         } else
654                 *next_delay = HZ / 10;
655
656         /* remember when we left the operating channel */
657         local->leave_oper_channel_time = jiffies;
658
659         /* advance to the next channel to be scanned */
660         local->next_scan_state = SCAN_SET_CHANNEL;
661 }
662
663 void ieee80211_scan_work(struct work_struct *work)
664 {
665         struct ieee80211_local *local =
666                 container_of(work, struct ieee80211_local, scan_work.work);
667         struct ieee80211_sub_if_data *sdata;
668         unsigned long next_delay = 0;
669         bool aborted, hw_scan;
670
671         mutex_lock(&local->mtx);
672
673         sdata = local->scan_sdata;
674
675         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
676                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
677                 goto out_complete;
678         }
679
680         if (!sdata || !local->scan_req)
681                 goto out;
682
683         if (local->scan_req && !local->scanning) {
684                 struct cfg80211_scan_request *req = local->scan_req;
685                 int rc;
686
687                 local->scan_req = NULL;
688                 local->scan_sdata = NULL;
689
690                 rc = __ieee80211_start_scan(sdata, req);
691                 if (rc) {
692                         /* need to complete scan in cfg80211 */
693                         local->scan_req = req;
694                         aborted = true;
695                         goto out_complete;
696                 } else
697                         goto out;
698         }
699
700         /*
701          * Avoid re-scheduling when the sdata is going away.
702          */
703         if (!ieee80211_sdata_running(sdata)) {
704                 aborted = true;
705                 goto out_complete;
706         }
707
708         /*
709          * as long as no delay is required advance immediately
710          * without scheduling a new work
711          */
712         do {
713                 if (!ieee80211_sdata_running(sdata)) {
714                         aborted = true;
715                         goto out_complete;
716                 }
717
718                 switch (local->next_scan_state) {
719                 case SCAN_DECISION:
720                         /* if no more bands/channels left, complete scan */
721                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
722                                 aborted = false;
723                                 goto out_complete;
724                         }
725                         ieee80211_scan_state_decision(local, &next_delay);
726                         break;
727                 case SCAN_SET_CHANNEL:
728                         ieee80211_scan_state_set_channel(local, &next_delay);
729                         break;
730                 case SCAN_SEND_PROBE:
731                         ieee80211_scan_state_send_probe(local, &next_delay);
732                         break;
733                 case SCAN_SUSPEND:
734                         ieee80211_scan_state_suspend(local, &next_delay);
735                         break;
736                 case SCAN_RESUME:
737                         ieee80211_scan_state_resume(local, &next_delay);
738                         break;
739                 }
740         } while (next_delay == 0);
741
742         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
743         goto out;
744
745 out_complete:
746         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
747         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
748 out:
749         mutex_unlock(&local->mtx);
750 }
751
752 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
753                            struct cfg80211_scan_request *req)
754 {
755         int res;
756
757         mutex_lock(&sdata->local->mtx);
758         res = __ieee80211_start_scan(sdata, req);
759         mutex_unlock(&sdata->local->mtx);
760
761         return res;
762 }
763
764 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
765                                     const u8 *ssid, u8 ssid_len,
766                                     struct ieee80211_channel *chan)
767 {
768         struct ieee80211_local *local = sdata->local;
769         int ret = -EBUSY;
770         enum ieee80211_band band;
771
772         mutex_lock(&local->mtx);
773
774         /* busy scanning */
775         if (local->scan_req)
776                 goto unlock;
777
778         /* fill internal scan request */
779         if (!chan) {
780                 int i, nchan = 0;
781
782                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
783                         if (!local->hw.wiphy->bands[band])
784                                 continue;
785                         for (i = 0;
786                              i < local->hw.wiphy->bands[band]->n_channels;
787                              i++) {
788                                 local->int_scan_req->channels[nchan] =
789                                     &local->hw.wiphy->bands[band]->channels[i];
790                                 nchan++;
791                         }
792                 }
793
794                 local->int_scan_req->n_channels = nchan;
795         } else {
796                 local->int_scan_req->channels[0] = chan;
797                 local->int_scan_req->n_channels = 1;
798         }
799
800         local->int_scan_req->ssids = &local->scan_ssid;
801         local->int_scan_req->n_ssids = 1;
802         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
803         local->int_scan_req->ssids[0].ssid_len = ssid_len;
804
805         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
806  unlock:
807         mutex_unlock(&local->mtx);
808         return ret;
809 }
810
811 /*
812  * Only call this function when a scan can't be queued -- under RTNL.
813  */
814 void ieee80211_scan_cancel(struct ieee80211_local *local)
815 {
816         /*
817          * We are canceling software scan, or deferred scan that was not
818          * yet really started (see __ieee80211_start_scan ).
819          *
820          * Regarding hardware scan:
821          * - we can not call  __ieee80211_scan_completed() as when
822          *   SCAN_HW_SCANNING bit is set this function change
823          *   local->hw_scan_req to operate on 5G band, what race with
824          *   driver which can use local->hw_scan_req
825          *
826          * - we can not cancel scan_work since driver can schedule it
827          *   by ieee80211_scan_completed(..., true) to finish scan
828          *
829          * Hence we only call the cancel_hw_scan() callback, but the low-level
830          * driver is still responsible for calling ieee80211_scan_completed()
831          * after the scan was completed/aborted.
832          */
833
834         mutex_lock(&local->mtx);
835         if (!local->scan_req)
836                 goto out;
837
838         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
839                 if (local->ops->cancel_hw_scan)
840                         drv_cancel_hw_scan(local, local->scan_sdata);
841                 goto out;
842         }
843
844         /*
845          * If the work is currently running, it must be blocked on
846          * the mutex, but we'll set scan_sdata = NULL and it'll
847          * simply exit once it acquires the mutex.
848          */
849         cancel_delayed_work(&local->scan_work);
850         /* and clean up */
851         __ieee80211_scan_completed(&local->hw, true, false);
852 out:
853         mutex_unlock(&local->mtx);
854 }
855
856 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
857                                        struct cfg80211_sched_scan_request *req)
858 {
859         struct ieee80211_local *local = sdata->local;
860         int ret, i;
861
862         mutex_lock(&sdata->local->mtx);
863
864         if (local->sched_scanning) {
865                 ret = -EBUSY;
866                 goto out;
867         }
868
869         if (!local->ops->sched_scan_start) {
870                 ret = -ENOTSUPP;
871                 goto out;
872         }
873
874         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
875                 local->sched_scan_ies.ie[i] = kzalloc(2 +
876                                                       IEEE80211_MAX_SSID_LEN +
877                                                       local->scan_ies_len +
878                                                       req->ie_len,
879                                                       GFP_KERNEL);
880                 if (!local->sched_scan_ies.ie[i]) {
881                         ret = -ENOMEM;
882                         goto out_free;
883                 }
884
885                 local->sched_scan_ies.len[i] =
886                         ieee80211_build_preq_ies(local,
887                                                  local->sched_scan_ies.ie[i],
888                                                  req->ie, req->ie_len, i,
889                                                  (u32) -1, 0);
890         }
891
892         ret = drv_sched_scan_start(local, sdata, req,
893                                    &local->sched_scan_ies);
894         if (ret == 0) {
895                 local->sched_scanning = true;
896                 goto out;
897         }
898
899 out_free:
900         while (i > 0)
901                 kfree(local->sched_scan_ies.ie[--i]);
902 out:
903         mutex_unlock(&sdata->local->mtx);
904         return ret;
905 }
906
907 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
908 {
909         struct ieee80211_local *local = sdata->local;
910         int ret = 0, i;
911
912         mutex_lock(&sdata->local->mtx);
913
914         if (!local->ops->sched_scan_stop) {
915                 ret = -ENOTSUPP;
916                 goto out;
917         }
918
919         if (local->sched_scanning) {
920                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
921                         kfree(local->sched_scan_ies.ie[i]);
922
923                 drv_sched_scan_stop(local, sdata);
924                 local->sched_scanning = false;
925         }
926 out:
927         mutex_unlock(&sdata->local->mtx);
928
929         return ret;
930 }
931
932 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
933 {
934         struct ieee80211_local *local = hw_to_local(hw);
935
936         trace_api_sched_scan_results(local);
937
938         cfg80211_sched_scan_results(hw->wiphy);
939 }
940 EXPORT_SYMBOL(ieee80211_sched_scan_results);
941
942 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
943 {
944         struct ieee80211_local *local =
945                 container_of(work, struct ieee80211_local,
946                              sched_scan_stopped_work);
947         int i;
948
949         mutex_lock(&local->mtx);
950
951         if (!local->sched_scanning) {
952                 mutex_unlock(&local->mtx);
953                 return;
954         }
955
956         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
957                 kfree(local->sched_scan_ies.ie[i]);
958
959         local->sched_scanning = false;
960
961         mutex_unlock(&local->mtx);
962
963         cfg80211_sched_scan_stopped(local->hw.wiphy);
964 }
965
966 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
967 {
968         struct ieee80211_local *local = hw_to_local(hw);
969
970         trace_api_sched_scan_stopped(local);
971
972         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
973 }
974 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);