mac80211: fix ie memory allocation for scheduled scans
[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         enum ieee80211_band band;
232         int i, ielen, n_chans;
233
234         do {
235                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
236                         return false;
237
238                 band = local->hw_scan_band;
239                 n_chans = 0;
240                 for (i = 0; i < req->n_channels; i++) {
241                         if (req->channels[i]->band == band) {
242                                 local->hw_scan_req->channels[n_chans] =
243                                                         req->channels[i];
244                                 n_chans++;
245                         }
246                 }
247
248                 local->hw_scan_band++;
249         } while (!n_chans);
250
251         local->hw_scan_req->n_channels = n_chans;
252
253         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
254                                          req->ie, req->ie_len, band, (u32) -1,
255                                          0);
256         local->hw_scan_req->ie_len = ielen;
257
258         return true;
259 }
260
261 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
262                                        bool was_hw_scan)
263 {
264         struct ieee80211_local *local = hw_to_local(hw);
265         bool on_oper_chan;
266         bool enable_beacons = false;
267
268         lockdep_assert_held(&local->mtx);
269
270         /*
271          * It's ok to abort a not-yet-running scan (that
272          * we have one at all will be verified by checking
273          * local->scan_req next), but not to complete it
274          * successfully.
275          */
276         if (WARN_ON(!local->scanning && !aborted))
277                 aborted = true;
278
279         if (WARN_ON(!local->scan_req))
280                 return;
281
282         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
283                 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
284                 if (rc == 0)
285                         return;
286         }
287
288         kfree(local->hw_scan_req);
289         local->hw_scan_req = NULL;
290
291         if (local->scan_req != local->int_scan_req)
292                 cfg80211_scan_done(local->scan_req, aborted);
293         local->scan_req = NULL;
294         local->scan_sdata = NULL;
295
296         local->scanning = 0;
297         local->scan_channel = NULL;
298
299         on_oper_chan = ieee80211_cfg_on_oper_channel(local);
300
301         if (was_hw_scan || !on_oper_chan)
302                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
303         else
304                 /* Set power back to normal operating levels. */
305                 ieee80211_hw_config(local, 0);
306
307         if (!was_hw_scan) {
308                 bool on_oper_chan2;
309                 ieee80211_configure_filter(local);
310                 drv_sw_scan_complete(local);
311                 on_oper_chan2 = ieee80211_cfg_on_oper_channel(local);
312                 /* We should always be on-channel at this point. */
313                 WARN_ON(!on_oper_chan2);
314                 if (on_oper_chan2 && (on_oper_chan != on_oper_chan2))
315                         enable_beacons = true;
316
317                 ieee80211_offchannel_return(local, enable_beacons, true);
318         }
319
320         ieee80211_recalc_idle(local);
321
322         ieee80211_mlme_notify_scan_completed(local);
323         ieee80211_ibss_notify_scan_completed(local);
324         ieee80211_mesh_notify_scan_completed(local);
325         ieee80211_queue_work(&local->hw, &local->work_work);
326 }
327
328 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
329 {
330         struct ieee80211_local *local = hw_to_local(hw);
331
332         trace_api_scan_completed(local, aborted);
333
334         set_bit(SCAN_COMPLETED, &local->scanning);
335         if (aborted)
336                 set_bit(SCAN_ABORTED, &local->scanning);
337         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
338 }
339 EXPORT_SYMBOL(ieee80211_scan_completed);
340
341 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
342 {
343         /*
344          * Hardware/driver doesn't support hw_scan, so use software
345          * scanning instead. First send a nullfunc frame with power save
346          * bit on so that AP will buffer the frames for us while we are not
347          * listening, then send probe requests to each channel and wait for
348          * the responses. After all channels are scanned, tune back to the
349          * original channel and send a nullfunc frame with power save bit
350          * off to trigger the AP to send us all the buffered frames.
351          *
352          * Note that while local->sw_scanning is true everything else but
353          * nullfunc frames and probe requests will be dropped in
354          * ieee80211_tx_h_check_assoc().
355          */
356         drv_sw_scan_start(local);
357
358         local->leave_oper_channel_time = 0;
359         local->next_scan_state = SCAN_DECISION;
360         local->scan_channel_idx = 0;
361
362         /* We always want to use off-channel PS, even if we
363          * are not really leaving oper-channel.  Don't
364          * tell the AP though, as long as we are on-channel.
365          */
366         ieee80211_offchannel_enable_all_ps(local, false);
367
368         ieee80211_configure_filter(local);
369
370         /* We need to set power level at maximum rate for scanning. */
371         ieee80211_hw_config(local, 0);
372
373         ieee80211_queue_delayed_work(&local->hw,
374                                      &local->scan_work,
375                                      IEEE80211_CHANNEL_TIME);
376
377         return 0;
378 }
379
380
381 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
382                                   struct cfg80211_scan_request *req)
383 {
384         struct ieee80211_local *local = sdata->local;
385         int rc;
386
387         lockdep_assert_held(&local->mtx);
388
389         if (local->scan_req)
390                 return -EBUSY;
391
392         if (!list_empty(&local->work_list)) {
393                 /* wait for the work to finish/time out */
394                 local->scan_req = req;
395                 local->scan_sdata = sdata;
396                 return 0;
397         }
398
399         if (local->ops->hw_scan) {
400                 u8 *ies;
401
402                 local->hw_scan_req = kmalloc(
403                                 sizeof(*local->hw_scan_req) +
404                                 req->n_channels * sizeof(req->channels[0]) +
405                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
406                                 req->ie_len, GFP_KERNEL);
407                 if (!local->hw_scan_req)
408                         return -ENOMEM;
409
410                 local->hw_scan_req->ssids = req->ssids;
411                 local->hw_scan_req->n_ssids = req->n_ssids;
412                 ies = (u8 *)local->hw_scan_req +
413                         sizeof(*local->hw_scan_req) +
414                         req->n_channels * sizeof(req->channels[0]);
415                 local->hw_scan_req->ie = ies;
416
417                 local->hw_scan_band = 0;
418
419                 /*
420                  * After allocating local->hw_scan_req, we must
421                  * go through until ieee80211_prep_hw_scan(), so
422                  * anything that might be changed here and leave
423                  * this function early must not go after this
424                  * allocation.
425                  */
426         }
427
428         local->scan_req = req;
429         local->scan_sdata = sdata;
430
431         if (local->ops->hw_scan)
432                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
433         else
434                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
435
436         ieee80211_recalc_idle(local);
437
438         if (local->ops->hw_scan) {
439                 WARN_ON(!ieee80211_prep_hw_scan(local));
440                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
441         } else
442                 rc = ieee80211_start_sw_scan(local);
443
444         if (rc) {
445                 kfree(local->hw_scan_req);
446                 local->hw_scan_req = NULL;
447                 local->scanning = 0;
448
449                 ieee80211_recalc_idle(local);
450
451                 local->scan_req = NULL;
452                 local->scan_sdata = NULL;
453         }
454
455         return rc;
456 }
457
458 static unsigned long
459 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
460 {
461         /*
462          * TODO: channel switching also consumes quite some time,
463          * add that delay as well to get a better estimation
464          */
465         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
466                 return IEEE80211_PASSIVE_CHANNEL_TIME;
467         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
468 }
469
470 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
471                                           unsigned long *next_delay)
472 {
473         bool associated = false;
474         bool tx_empty = true;
475         bool bad_latency;
476         bool listen_int_exceeded;
477         unsigned long min_beacon_int = 0;
478         struct ieee80211_sub_if_data *sdata;
479         struct ieee80211_channel *next_chan;
480
481         /*
482          * check if at least one STA interface is associated,
483          * check if at least one STA interface has pending tx frames
484          * and grab the lowest used beacon interval
485          */
486         mutex_lock(&local->iflist_mtx);
487         list_for_each_entry(sdata, &local->interfaces, list) {
488                 if (!ieee80211_sdata_running(sdata))
489                         continue;
490
491                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
492                         if (sdata->u.mgd.associated) {
493                                 associated = true;
494
495                                 if (sdata->vif.bss_conf.beacon_int <
496                                     min_beacon_int || min_beacon_int == 0)
497                                         min_beacon_int =
498                                                 sdata->vif.bss_conf.beacon_int;
499
500                                 if (!qdisc_all_tx_empty(sdata->dev)) {
501                                         tx_empty = false;
502                                         break;
503                                 }
504                         }
505                 }
506         }
507         mutex_unlock(&local->iflist_mtx);
508
509         next_chan = local->scan_req->channels[local->scan_channel_idx];
510
511         if (ieee80211_cfg_on_oper_channel(local)) {
512                 /* We're currently on operating channel. */
513                 if (next_chan == local->oper_channel)
514                         /* We don't need to move off of operating channel. */
515                         local->next_scan_state = SCAN_SET_CHANNEL;
516                 else
517                         /*
518                          * We do need to leave operating channel, as next
519                          * scan is somewhere else.
520                          */
521                         local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
522         } else {
523                 /*
524                  * we're currently scanning a different channel, let's
525                  * see if we can scan another channel without interfering
526                  * with the current traffic situation.
527                  *
528                  * Since we don't know if the AP has pending frames for us
529                  * we can only check for our tx queues and use the current
530                  * pm_qos requirements for rx. Hence, if no tx traffic occurs
531                  * at all we will scan as many channels in a row as the pm_qos
532                  * latency allows us to. Additionally we also check for the
533                  * currently negotiated listen interval to prevent losing
534                  * frames unnecessarily.
535                  *
536                  * Otherwise switch back to the operating channel.
537                  */
538
539                 bad_latency = time_after(jiffies +
540                                 ieee80211_scan_get_channel_time(next_chan),
541                                 local->leave_oper_channel_time +
542                                 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
543
544                 listen_int_exceeded = time_after(jiffies +
545                                 ieee80211_scan_get_channel_time(next_chan),
546                                 local->leave_oper_channel_time +
547                                 usecs_to_jiffies(min_beacon_int * 1024) *
548                                 local->hw.conf.listen_interval);
549
550                 if (associated && ( !tx_empty || bad_latency ||
551                     listen_int_exceeded))
552                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
553                 else
554                         local->next_scan_state = SCAN_SET_CHANNEL;
555         }
556
557         *next_delay = 0;
558 }
559
560 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
561                                                     unsigned long *next_delay)
562 {
563         /* PS will already be in off-channel mode,
564          * we do that once at the beginning of scanning.
565          */
566         ieee80211_offchannel_stop_vifs(local, false);
567
568         /*
569          * What if the nullfunc frames didn't arrive?
570          */
571         drv_flush(local, false);
572         if (local->ops->flush)
573                 *next_delay = 0;
574         else
575                 *next_delay = HZ / 10;
576
577         /* remember when we left the operating channel */
578         local->leave_oper_channel_time = jiffies;
579
580         /* advance to the next channel to be scanned */
581         local->next_scan_state = SCAN_SET_CHANNEL;
582 }
583
584 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
585                                                     unsigned long *next_delay)
586 {
587         /* switch back to the operating channel */
588         local->scan_channel = NULL;
589         if (!ieee80211_cfg_on_oper_channel(local))
590                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
591
592         /*
593          * Re-enable vifs and beaconing.  Leave PS
594          * in off-channel state..will put that back
595          * on-channel at the end of scanning.
596          */
597         ieee80211_offchannel_return(local, true, false);
598
599         *next_delay = HZ / 5;
600         local->next_scan_state = SCAN_DECISION;
601 }
602
603 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
604                                              unsigned long *next_delay)
605 {
606         int skip;
607         struct ieee80211_channel *chan;
608
609         skip = 0;
610         chan = local->scan_req->channels[local->scan_channel_idx];
611
612         local->scan_channel = chan;
613
614         /* Only call hw-config if we really need to change channels. */
615         if (chan != local->hw.conf.channel)
616                 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
617                         skip = 1;
618
619         /* advance state machine to next channel/band */
620         local->scan_channel_idx++;
621
622         if (skip) {
623                 /* if we skip this channel return to the decision state */
624                 local->next_scan_state = SCAN_DECISION;
625                 return;
626         }
627
628         /*
629          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
630          * (which unfortunately doesn't say _why_ step a) is done,
631          * but it waits for the probe delay or until a frame is
632          * received - and the received frame would update the NAV).
633          * For now, we do not support waiting until a frame is
634          * received.
635          *
636          * In any case, it is not necessary for a passive scan.
637          */
638         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
639             !local->scan_req->n_ssids) {
640                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
641                 local->next_scan_state = SCAN_DECISION;
642                 return;
643         }
644
645         /* active scan, send probes */
646         *next_delay = IEEE80211_PROBE_DELAY;
647         local->next_scan_state = SCAN_SEND_PROBE;
648 }
649
650 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
651                                             unsigned long *next_delay)
652 {
653         int i;
654         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
655
656         for (i = 0; i < local->scan_req->n_ssids; i++)
657                 ieee80211_send_probe_req(
658                         sdata, NULL,
659                         local->scan_req->ssids[i].ssid,
660                         local->scan_req->ssids[i].ssid_len,
661                         local->scan_req->ie, local->scan_req->ie_len);
662
663         /*
664          * After sending probe requests, wait for probe responses
665          * on the channel.
666          */
667         *next_delay = IEEE80211_CHANNEL_TIME;
668         local->next_scan_state = SCAN_DECISION;
669 }
670
671 void ieee80211_scan_work(struct work_struct *work)
672 {
673         struct ieee80211_local *local =
674                 container_of(work, struct ieee80211_local, scan_work.work);
675         struct ieee80211_sub_if_data *sdata;
676         unsigned long next_delay = 0;
677         bool aborted, hw_scan;
678
679         mutex_lock(&local->mtx);
680
681         sdata = local->scan_sdata;
682
683         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
684                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
685                 goto out_complete;
686         }
687
688         if (!sdata || !local->scan_req)
689                 goto out;
690
691         if (local->scan_req && !local->scanning) {
692                 struct cfg80211_scan_request *req = local->scan_req;
693                 int rc;
694
695                 local->scan_req = NULL;
696                 local->scan_sdata = NULL;
697
698                 rc = __ieee80211_start_scan(sdata, req);
699                 if (rc) {
700                         /* need to complete scan in cfg80211 */
701                         local->scan_req = req;
702                         aborted = true;
703                         goto out_complete;
704                 } else
705                         goto out;
706         }
707
708         /*
709          * Avoid re-scheduling when the sdata is going away.
710          */
711         if (!ieee80211_sdata_running(sdata)) {
712                 aborted = true;
713                 goto out_complete;
714         }
715
716         /*
717          * as long as no delay is required advance immediately
718          * without scheduling a new work
719          */
720         do {
721                 if (!ieee80211_sdata_running(sdata)) {
722                         aborted = true;
723                         goto out_complete;
724                 }
725
726                 switch (local->next_scan_state) {
727                 case SCAN_DECISION:
728                         /* if no more bands/channels left, complete scan */
729                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
730                                 aborted = false;
731                                 goto out_complete;
732                         }
733                         ieee80211_scan_state_decision(local, &next_delay);
734                         break;
735                 case SCAN_SET_CHANNEL:
736                         ieee80211_scan_state_set_channel(local, &next_delay);
737                         break;
738                 case SCAN_SEND_PROBE:
739                         ieee80211_scan_state_send_probe(local, &next_delay);
740                         break;
741                 case SCAN_LEAVE_OPER_CHANNEL:
742                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
743                         break;
744                 case SCAN_ENTER_OPER_CHANNEL:
745                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
746                         break;
747                 }
748         } while (next_delay == 0);
749
750         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
751         goto out;
752
753 out_complete:
754         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
755         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
756 out:
757         mutex_unlock(&local->mtx);
758 }
759
760 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
761                            struct cfg80211_scan_request *req)
762 {
763         int res;
764
765         mutex_lock(&sdata->local->mtx);
766         res = __ieee80211_start_scan(sdata, req);
767         mutex_unlock(&sdata->local->mtx);
768
769         return res;
770 }
771
772 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
773                                     const u8 *ssid, u8 ssid_len,
774                                     struct ieee80211_channel *chan)
775 {
776         struct ieee80211_local *local = sdata->local;
777         int ret = -EBUSY;
778         enum ieee80211_band band;
779
780         mutex_lock(&local->mtx);
781
782         /* busy scanning */
783         if (local->scan_req)
784                 goto unlock;
785
786         /* fill internal scan request */
787         if (!chan) {
788                 int i, nchan = 0;
789
790                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
791                         if (!local->hw.wiphy->bands[band])
792                                 continue;
793                         for (i = 0;
794                              i < local->hw.wiphy->bands[band]->n_channels;
795                              i++) {
796                                 local->int_scan_req->channels[nchan] =
797                                     &local->hw.wiphy->bands[band]->channels[i];
798                                 nchan++;
799                         }
800                 }
801
802                 local->int_scan_req->n_channels = nchan;
803         } else {
804                 local->int_scan_req->channels[0] = chan;
805                 local->int_scan_req->n_channels = 1;
806         }
807
808         local->int_scan_req->ssids = &local->scan_ssid;
809         local->int_scan_req->n_ssids = 1;
810         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
811         local->int_scan_req->ssids[0].ssid_len = ssid_len;
812
813         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
814  unlock:
815         mutex_unlock(&local->mtx);
816         return ret;
817 }
818
819 /*
820  * Only call this function when a scan can't be queued -- under RTNL.
821  */
822 void ieee80211_scan_cancel(struct ieee80211_local *local)
823 {
824         bool abortscan;
825
826         /*
827          * We are only 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 low lever driver is responsible for canceling HW scan.
840          */
841
842         mutex_lock(&local->mtx);
843         abortscan = local->scan_req && !test_bit(SCAN_HW_SCANNING, &local->scanning);
844         if (abortscan) {
845                 /*
846                  * The scan is canceled, but stop work from being pending.
847                  *
848                  * If the work is currently running, it must be blocked on
849                  * the mutex, but we'll set scan_sdata = NULL and it'll
850                  * simply exit once it acquires the mutex.
851                  */
852                 cancel_delayed_work(&local->scan_work);
853                 /* and clean up */
854                 __ieee80211_scan_completed(&local->hw, true, false);
855         }
856         mutex_unlock(&local->mtx);
857 }
858
859 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
860                                        struct cfg80211_sched_scan_request *req)
861 {
862         struct ieee80211_local *local = sdata->local;
863         int ret, i;
864
865         mutex_lock(&sdata->local->mtx);
866
867         if (local->sched_scanning) {
868                 ret = -EBUSY;
869                 goto out;
870         }
871
872         if (!local->ops->sched_scan_start) {
873                 ret = -ENOTSUPP;
874                 goto out;
875         }
876
877         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
878                 local->sched_scan_ies.ie[i] = kzalloc(2 +
879                                                       IEEE80211_MAX_SSID_LEN +
880                                                       local->scan_ies_len +
881                                                       req->ie_len,
882                                                       GFP_KERNEL);
883                 if (!local->sched_scan_ies.ie[i]) {
884                         ret = -ENOMEM;
885                         goto out_free;
886                 }
887
888                 local->sched_scan_ies.len[i] =
889                         ieee80211_build_preq_ies(local,
890                                                  local->sched_scan_ies.ie[i],
891                                                  req->ie, req->ie_len, i,
892                                                  (u32) -1, 0);
893         }
894
895         ret = drv_sched_scan_start(local, sdata, req,
896                                    &local->sched_scan_ies);
897         if (ret == 0) {
898                 local->sched_scanning = true;
899                 goto out;
900         }
901
902 out_free:
903         while (i > 0)
904                 kfree(local->sched_scan_ies.ie[--i]);
905 out:
906         mutex_unlock(&sdata->local->mtx);
907         return ret;
908 }
909
910 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
911 {
912         struct ieee80211_local *local = sdata->local;
913         int ret = 0, i;
914
915         mutex_lock(&sdata->local->mtx);
916
917         if (!local->ops->sched_scan_stop) {
918                 ret = -ENOTSUPP;
919                 goto out;
920         }
921
922         if (local->sched_scanning) {
923                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
924                         kfree(local->sched_scan_ies.ie[i]);
925
926                 drv_sched_scan_stop(local, sdata);
927                 local->sched_scanning = false;
928         }
929 out:
930         mutex_unlock(&sdata->local->mtx);
931
932         return ret;
933 }
934
935 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
936 {
937         struct ieee80211_local *local = hw_to_local(hw);
938
939         trace_api_sched_scan_results(local);
940
941         cfg80211_sched_scan_results(hw->wiphy);
942 }
943 EXPORT_SYMBOL(ieee80211_sched_scan_results);
944
945 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
946 {
947         struct ieee80211_local *local =
948                 container_of(work, struct ieee80211_local,
949                              sched_scan_stopped_work);
950         int i;
951
952         mutex_lock(&local->mtx);
953
954         if (!local->sched_scanning) {
955                 mutex_unlock(&local->mtx);
956                 return;
957         }
958
959         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
960                 kfree(local->sched_scan_ies.ie[i]);
961
962         local->sched_scanning = false;
963
964         mutex_unlock(&local->mtx);
965
966         cfg80211_sched_scan_stopped(local->hw.wiphy);
967 }
968
969 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
970 {
971         struct ieee80211_local *local = hw_to_local(hw);
972
973         trace_api_sched_scan_stopped(local);
974
975         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
976 }
977 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);