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.h>
18 #include <net/sch_generic.h>
19 #include <linux/slab.h>
20 #include <linux/export.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 *
ieee80211_rx_bss_get(struct ieee80211_local * local,u8 * bssid,int freq,u8 * ssid,u8 ssid_len)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
ieee80211_rx_bss_free(struct cfg80211_bss * cbss)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
ieee80211_rx_bss_put(struct ieee80211_local * local,struct ieee80211_bss * bss)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
is_uapsd_supported(struct ieee802_11_elems * elems)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 *
ieee80211_bss_info_update(struct ieee80211_local * local,struct ieee80211_rx_status * rx_status,struct ieee80211_mgmt * mgmt,size_t len,struct ieee802_11_elems * elems,struct ieee80211_channel * channel,bool beacon)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 = true;
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
ieee80211_scan_rx(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)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 (channel == sdata->local->oper_channel)
217 return RX_CONTINUE;
218
219 dev_kfree_skb(skb);
220 return RX_QUEUED;
221 }
222
223 /* return false if no more work */
ieee80211_prep_hw_scan(struct ieee80211_local * local)224 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
225 {
226 struct cfg80211_scan_request *req = local->scan_req;
227 enum ieee80211_band band;
228 int i, ielen, n_chans;
229
230 do {
231 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
232 return false;
233
234 band = local->hw_scan_band;
235 n_chans = 0;
236 for (i = 0; i < req->n_channels; i++) {
237 if (req->channels[i]->band == band) {
238 local->hw_scan_req->channels[n_chans] =
239 req->channels[i];
240 n_chans++;
241 }
242 }
243
244 local->hw_scan_band++;
245 } while (!n_chans);
246
247 local->hw_scan_req->n_channels = n_chans;
248
249 ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
250 req->ie, req->ie_len, band,
251 req->rates[band], 0);
252 local->hw_scan_req->ie_len = ielen;
253 local->hw_scan_req->no_cck = req->no_cck;
254
255 return true;
256 }
257
__ieee80211_scan_completed(struct ieee80211_hw * hw,bool aborted,bool was_hw_scan)258 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
259 bool was_hw_scan)
260 {
261 struct ieee80211_local *local = hw_to_local(hw);
262
263 lockdep_assert_held(&local->mtx);
264
265 /*
266 * It's ok to abort a not-yet-running scan (that
267 * we have one at all will be verified by checking
268 * local->scan_req next), but not to complete it
269 * successfully.
270 */
271 if (WARN_ON(!local->scanning && !aborted))
272 aborted = true;
273
274 if (WARN_ON(!local->scan_req))
275 return;
276
277 if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
278 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
279 if (rc == 0)
280 return;
281 }
282
283 kfree(local->hw_scan_req);
284 local->hw_scan_req = NULL;
285
286 if (local->scan_req != local->int_scan_req)
287 cfg80211_scan_done(local->scan_req, aborted);
288 local->scan_req = NULL;
289 local->scan_sdata = NULL;
290
291 local->scanning = 0;
292 local->scan_channel = NULL;
293
294 /* Set power back to normal operating levels. */
295 ieee80211_hw_config(local, 0);
296
297 if (!was_hw_scan) {
298 ieee80211_configure_filter(local);
299 drv_sw_scan_complete(local);
300 ieee80211_offchannel_return(local, true);
301 }
302
303 ieee80211_recalc_idle(local);
304
305 ieee80211_mlme_notify_scan_completed(local);
306 ieee80211_ibss_notify_scan_completed(local);
307 ieee80211_mesh_notify_scan_completed(local);
308 ieee80211_queue_work(&local->hw, &local->work_work);
309 }
310
ieee80211_scan_completed(struct ieee80211_hw * hw,bool aborted)311 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
312 {
313 struct ieee80211_local *local = hw_to_local(hw);
314
315 trace_api_scan_completed(local, aborted);
316
317 set_bit(SCAN_COMPLETED, &local->scanning);
318 if (aborted)
319 set_bit(SCAN_ABORTED, &local->scanning);
320 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
321 }
322 EXPORT_SYMBOL(ieee80211_scan_completed);
323
ieee80211_start_sw_scan(struct ieee80211_local * local)324 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
325 {
326 /*
327 * Hardware/driver doesn't support hw_scan, so use software
328 * scanning instead. First send a nullfunc frame with power save
329 * bit on so that AP will buffer the frames for us while we are not
330 * listening, then send probe requests to each channel and wait for
331 * the responses. After all channels are scanned, tune back to the
332 * original channel and send a nullfunc frame with power save bit
333 * off to trigger the AP to send us all the buffered frames.
334 *
335 * Note that while local->sw_scanning is true everything else but
336 * nullfunc frames and probe requests will be dropped in
337 * ieee80211_tx_h_check_assoc().
338 */
339 drv_sw_scan_start(local);
340
341 local->leave_oper_channel_time = 0;
342 local->next_scan_state = SCAN_DECISION;
343 local->scan_channel_idx = 0;
344
345 ieee80211_offchannel_stop_vifs(local, true);
346
347 ieee80211_configure_filter(local);
348
349 /* We need to set power level at maximum rate for scanning. */
350 ieee80211_hw_config(local, 0);
351
352 ieee80211_queue_delayed_work(&local->hw,
353 &local->scan_work, 0);
354
355 return 0;
356 }
357
358
__ieee80211_start_scan(struct ieee80211_sub_if_data * sdata,struct cfg80211_scan_request * req)359 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
360 struct cfg80211_scan_request *req)
361 {
362 struct ieee80211_local *local = sdata->local;
363 int rc;
364
365 lockdep_assert_held(&local->mtx);
366
367 if (local->scan_req)
368 return -EBUSY;
369
370 if (!list_empty(&local->work_list)) {
371 /* wait for the work to finish/time out */
372 local->scan_req = req;
373 local->scan_sdata = sdata;
374 return 0;
375 }
376
377 if (local->ops->hw_scan) {
378 u8 *ies;
379
380 local->hw_scan_req = kmalloc(
381 sizeof(*local->hw_scan_req) +
382 req->n_channels * sizeof(req->channels[0]) +
383 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
384 req->ie_len, GFP_KERNEL);
385 if (!local->hw_scan_req)
386 return -ENOMEM;
387
388 local->hw_scan_req->ssids = req->ssids;
389 local->hw_scan_req->n_ssids = req->n_ssids;
390 ies = (u8 *)local->hw_scan_req +
391 sizeof(*local->hw_scan_req) +
392 req->n_channels * sizeof(req->channels[0]);
393 local->hw_scan_req->ie = ies;
394
395 local->hw_scan_band = 0;
396
397 /*
398 * After allocating local->hw_scan_req, we must
399 * go through until ieee80211_prep_hw_scan(), so
400 * anything that might be changed here and leave
401 * this function early must not go after this
402 * allocation.
403 */
404 }
405
406 local->scan_req = req;
407 local->scan_sdata = sdata;
408
409 if (local->ops->hw_scan)
410 __set_bit(SCAN_HW_SCANNING, &local->scanning);
411 else
412 __set_bit(SCAN_SW_SCANNING, &local->scanning);
413
414 ieee80211_recalc_idle(local);
415
416 if (local->ops->hw_scan) {
417 WARN_ON(!ieee80211_prep_hw_scan(local));
418 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
419 } else
420 rc = ieee80211_start_sw_scan(local);
421
422 if (rc) {
423 kfree(local->hw_scan_req);
424 local->hw_scan_req = NULL;
425 local->scanning = 0;
426
427 ieee80211_recalc_idle(local);
428
429 local->scan_req = NULL;
430 local->scan_sdata = NULL;
431 }
432
433 return rc;
434 }
435
436 static unsigned long
ieee80211_scan_get_channel_time(struct ieee80211_channel * chan)437 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
438 {
439 /*
440 * TODO: channel switching also consumes quite some time,
441 * add that delay as well to get a better estimation
442 */
443 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
444 return IEEE80211_PASSIVE_CHANNEL_TIME;
445 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
446 }
447
ieee80211_scan_state_decision(struct ieee80211_local * local,unsigned long * next_delay)448 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
449 unsigned long *next_delay)
450 {
451 bool associated = false;
452 bool tx_empty = true;
453 bool bad_latency;
454 bool listen_int_exceeded;
455 unsigned long min_beacon_int = 0;
456 struct ieee80211_sub_if_data *sdata;
457 struct ieee80211_channel *next_chan;
458
459 /*
460 * check if at least one STA interface is associated,
461 * check if at least one STA interface has pending tx frames
462 * and grab the lowest used beacon interval
463 */
464 mutex_lock(&local->iflist_mtx);
465 list_for_each_entry(sdata, &local->interfaces, list) {
466 if (!ieee80211_sdata_running(sdata))
467 continue;
468
469 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
470 if (sdata->u.mgd.associated) {
471 associated = true;
472
473 if (sdata->vif.bss_conf.beacon_int <
474 min_beacon_int || min_beacon_int == 0)
475 min_beacon_int =
476 sdata->vif.bss_conf.beacon_int;
477
478 if (!qdisc_all_tx_empty(sdata->dev)) {
479 tx_empty = false;
480 break;
481 }
482 }
483 }
484 }
485 mutex_unlock(&local->iflist_mtx);
486
487 next_chan = local->scan_req->channels[local->scan_channel_idx];
488
489 /*
490 * we're currently scanning a different channel, let's
491 * see if we can scan another channel without interfering
492 * with the current traffic situation.
493 *
494 * Since we don't know if the AP has pending frames for us
495 * we can only check for our tx queues and use the current
496 * pm_qos requirements for rx. Hence, if no tx traffic occurs
497 * at all we will scan as many channels in a row as the pm_qos
498 * latency allows us to. Additionally we also check for the
499 * currently negotiated listen interval to prevent losing
500 * frames unnecessarily.
501 *
502 * Otherwise switch back to the operating channel.
503 */
504
505 bad_latency = time_after(jiffies +
506 ieee80211_scan_get_channel_time(next_chan),
507 local->leave_oper_channel_time +
508 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
509
510 listen_int_exceeded = time_after(jiffies +
511 ieee80211_scan_get_channel_time(next_chan),
512 local->leave_oper_channel_time +
513 usecs_to_jiffies(min_beacon_int * 1024) *
514 local->hw.conf.listen_interval);
515
516 if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
517 local->next_scan_state = SCAN_SUSPEND;
518 else
519 local->next_scan_state = SCAN_SET_CHANNEL;
520
521 *next_delay = 0;
522 }
523
ieee80211_scan_state_set_channel(struct ieee80211_local * local,unsigned long * next_delay)524 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
525 unsigned long *next_delay)
526 {
527 int skip;
528 struct ieee80211_channel *chan;
529
530 skip = 0;
531 chan = local->scan_req->channels[local->scan_channel_idx];
532
533 local->scan_channel = chan;
534
535 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
536 skip = 1;
537
538 /* advance state machine to next channel/band */
539 local->scan_channel_idx++;
540
541 if (skip) {
542 /* if we skip this channel return to the decision state */
543 local->next_scan_state = SCAN_DECISION;
544 return;
545 }
546
547 /*
548 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
549 * (which unfortunately doesn't say _why_ step a) is done,
550 * but it waits for the probe delay or until a frame is
551 * received - and the received frame would update the NAV).
552 * For now, we do not support waiting until a frame is
553 * received.
554 *
555 * In any case, it is not necessary for a passive scan.
556 */
557 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
558 !local->scan_req->n_ssids) {
559 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
560 local->next_scan_state = SCAN_DECISION;
561 return;
562 }
563
564 /* active scan, send probes */
565 *next_delay = IEEE80211_PROBE_DELAY;
566 local->next_scan_state = SCAN_SEND_PROBE;
567 }
568
ieee80211_scan_state_send_probe(struct ieee80211_local * local,unsigned long * next_delay)569 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
570 unsigned long *next_delay)
571 {
572 int i;
573 struct ieee80211_sub_if_data *sdata = local->scan_sdata;
574 enum ieee80211_band band = local->hw.conf.channel->band;
575
576 for (i = 0; i < local->scan_req->n_ssids; i++)
577 ieee80211_send_probe_req(
578 sdata, NULL,
579 local->scan_req->ssids[i].ssid,
580 local->scan_req->ssids[i].ssid_len,
581 local->scan_req->ie, local->scan_req->ie_len,
582 local->scan_req->rates[band], false,
583 local->scan_req->no_cck);
584
585 /*
586 * After sending probe requests, wait for probe responses
587 * on the channel.
588 */
589 *next_delay = IEEE80211_CHANNEL_TIME;
590 local->next_scan_state = SCAN_DECISION;
591 }
592
ieee80211_scan_state_suspend(struct ieee80211_local * local,unsigned long * next_delay)593 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
594 unsigned long *next_delay)
595 {
596 /* switch back to the operating channel */
597 local->scan_channel = NULL;
598 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
599
600 /*
601 * Re-enable vifs and beaconing. Leave PS
602 * in off-channel state..will put that back
603 * on-channel at the end of scanning.
604 */
605 ieee80211_offchannel_return(local, false);
606
607 *next_delay = HZ / 5;
608 /* afterwards, resume scan & go to next channel */
609 local->next_scan_state = SCAN_RESUME;
610 }
611
ieee80211_scan_state_resume(struct ieee80211_local * local,unsigned long * next_delay)612 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
613 unsigned long *next_delay)
614 {
615 /* PS already is in off-channel mode */
616 ieee80211_offchannel_stop_vifs(local, false);
617
618 if (local->ops->flush) {
619 drv_flush(local, false);
620 *next_delay = 0;
621 } else
622 *next_delay = HZ / 10;
623
624 /* remember when we left the operating channel */
625 local->leave_oper_channel_time = jiffies;
626
627 /* advance to the next channel to be scanned */
628 local->next_scan_state = SCAN_SET_CHANNEL;
629 }
630
ieee80211_scan_work(struct work_struct * work)631 void ieee80211_scan_work(struct work_struct *work)
632 {
633 struct ieee80211_local *local =
634 container_of(work, struct ieee80211_local, scan_work.work);
635 struct ieee80211_sub_if_data *sdata;
636 unsigned long next_delay = 0;
637 bool aborted, hw_scan;
638
639 mutex_lock(&local->mtx);
640
641 sdata = local->scan_sdata;
642
643 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
644 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
645 goto out_complete;
646 }
647
648 if (!sdata || !local->scan_req)
649 goto out;
650
651 if (local->scan_req && !local->scanning) {
652 struct cfg80211_scan_request *req = local->scan_req;
653 int rc;
654
655 local->scan_req = NULL;
656 local->scan_sdata = NULL;
657
658 rc = __ieee80211_start_scan(sdata, req);
659 if (rc) {
660 /* need to complete scan in cfg80211 */
661 local->scan_req = req;
662 aborted = true;
663 goto out_complete;
664 } else
665 goto out;
666 }
667
668 /*
669 * Avoid re-scheduling when the sdata is going away.
670 */
671 if (!ieee80211_sdata_running(sdata)) {
672 aborted = true;
673 goto out_complete;
674 }
675
676 /*
677 * as long as no delay is required advance immediately
678 * without scheduling a new work
679 */
680 do {
681 if (!ieee80211_sdata_running(sdata)) {
682 aborted = true;
683 goto out_complete;
684 }
685
686 switch (local->next_scan_state) {
687 case SCAN_DECISION:
688 /* if no more bands/channels left, complete scan */
689 if (local->scan_channel_idx >= local->scan_req->n_channels) {
690 aborted = false;
691 goto out_complete;
692 }
693 ieee80211_scan_state_decision(local, &next_delay);
694 break;
695 case SCAN_SET_CHANNEL:
696 ieee80211_scan_state_set_channel(local, &next_delay);
697 break;
698 case SCAN_SEND_PROBE:
699 ieee80211_scan_state_send_probe(local, &next_delay);
700 break;
701 case SCAN_SUSPEND:
702 ieee80211_scan_state_suspend(local, &next_delay);
703 break;
704 case SCAN_RESUME:
705 ieee80211_scan_state_resume(local, &next_delay);
706 break;
707 }
708 } while (next_delay == 0);
709
710 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
711 goto out;
712
713 out_complete:
714 hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
715 __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
716 out:
717 mutex_unlock(&local->mtx);
718 }
719
ieee80211_request_scan(struct ieee80211_sub_if_data * sdata,struct cfg80211_scan_request * req)720 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
721 struct cfg80211_scan_request *req)
722 {
723 int res;
724
725 mutex_lock(&sdata->local->mtx);
726 res = __ieee80211_start_scan(sdata, req);
727 mutex_unlock(&sdata->local->mtx);
728
729 return res;
730 }
731
ieee80211_request_internal_scan(struct ieee80211_sub_if_data * sdata,const u8 * ssid,u8 ssid_len,struct ieee80211_channel * chan)732 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
733 const u8 *ssid, u8 ssid_len,
734 struct ieee80211_channel *chan)
735 {
736 struct ieee80211_local *local = sdata->local;
737 int ret = -EBUSY;
738 enum ieee80211_band band;
739
740 mutex_lock(&local->mtx);
741
742 /* busy scanning */
743 if (local->scan_req)
744 goto unlock;
745
746 /* fill internal scan request */
747 if (!chan) {
748 int i, nchan = 0;
749
750 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
751 if (!local->hw.wiphy->bands[band])
752 continue;
753 for (i = 0;
754 i < local->hw.wiphy->bands[band]->n_channels;
755 i++) {
756 local->int_scan_req->channels[nchan] =
757 &local->hw.wiphy->bands[band]->channels[i];
758 nchan++;
759 }
760 }
761
762 local->int_scan_req->n_channels = nchan;
763 } else {
764 local->int_scan_req->channels[0] = chan;
765 local->int_scan_req->n_channels = 1;
766 }
767
768 local->int_scan_req->ssids = &local->scan_ssid;
769 local->int_scan_req->n_ssids = 1;
770 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
771 local->int_scan_req->ssids[0].ssid_len = ssid_len;
772
773 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
774 unlock:
775 mutex_unlock(&local->mtx);
776 return ret;
777 }
778
779 /*
780 * Only call this function when a scan can't be queued -- under RTNL.
781 */
ieee80211_scan_cancel(struct ieee80211_local * local)782 void ieee80211_scan_cancel(struct ieee80211_local *local)
783 {
784 /*
785 * We are canceling software scan, or deferred scan that was not
786 * yet really started (see __ieee80211_start_scan ).
787 *
788 * Regarding hardware scan:
789 * - we can not call __ieee80211_scan_completed() as when
790 * SCAN_HW_SCANNING bit is set this function change
791 * local->hw_scan_req to operate on 5G band, what race with
792 * driver which can use local->hw_scan_req
793 *
794 * - we can not cancel scan_work since driver can schedule it
795 * by ieee80211_scan_completed(..., true) to finish scan
796 *
797 * Hence we only call the cancel_hw_scan() callback, but the low-level
798 * driver is still responsible for calling ieee80211_scan_completed()
799 * after the scan was completed/aborted.
800 */
801
802 mutex_lock(&local->mtx);
803 if (!local->scan_req)
804 goto out;
805
806 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
807 if (local->ops->cancel_hw_scan)
808 drv_cancel_hw_scan(local, local->scan_sdata);
809 goto out;
810 }
811
812 /*
813 * If the work is currently running, it must be blocked on
814 * the mutex, but we'll set scan_sdata = NULL and it'll
815 * simply exit once it acquires the mutex.
816 */
817 cancel_delayed_work(&local->scan_work);
818 /* and clean up */
819 __ieee80211_scan_completed(&local->hw, true, false);
820 out:
821 mutex_unlock(&local->mtx);
822 }
823
ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data * sdata,struct cfg80211_sched_scan_request * req)824 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
825 struct cfg80211_sched_scan_request *req)
826 {
827 struct ieee80211_local *local = sdata->local;
828 int ret, i;
829
830 mutex_lock(&sdata->local->mtx);
831
832 if (local->sched_scanning) {
833 ret = -EBUSY;
834 goto out;
835 }
836
837 if (!local->ops->sched_scan_start) {
838 ret = -ENOTSUPP;
839 goto out;
840 }
841
842 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
843 local->sched_scan_ies.ie[i] = kzalloc(2 +
844 IEEE80211_MAX_SSID_LEN +
845 local->scan_ies_len +
846 req->ie_len,
847 GFP_KERNEL);
848 if (!local->sched_scan_ies.ie[i]) {
849 ret = -ENOMEM;
850 goto out_free;
851 }
852
853 local->sched_scan_ies.len[i] =
854 ieee80211_build_preq_ies(local,
855 local->sched_scan_ies.ie[i],
856 req->ie, req->ie_len, i,
857 (u32) -1, 0);
858 }
859
860 ret = drv_sched_scan_start(local, sdata, req,
861 &local->sched_scan_ies);
862 if (ret == 0) {
863 local->sched_scanning = true;
864 goto out;
865 }
866
867 out_free:
868 while (i > 0)
869 kfree(local->sched_scan_ies.ie[--i]);
870 out:
871 mutex_unlock(&sdata->local->mtx);
872 return ret;
873 }
874
ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data * sdata)875 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
876 {
877 struct ieee80211_local *local = sdata->local;
878 int ret = 0, i;
879
880 mutex_lock(&sdata->local->mtx);
881
882 if (!local->ops->sched_scan_stop) {
883 ret = -ENOTSUPP;
884 goto out;
885 }
886
887 if (local->sched_scanning) {
888 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
889 kfree(local->sched_scan_ies.ie[i]);
890
891 drv_sched_scan_stop(local, sdata);
892 local->sched_scanning = false;
893 }
894 out:
895 mutex_unlock(&sdata->local->mtx);
896
897 return ret;
898 }
899
ieee80211_sched_scan_results(struct ieee80211_hw * hw)900 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
901 {
902 struct ieee80211_local *local = hw_to_local(hw);
903
904 trace_api_sched_scan_results(local);
905
906 cfg80211_sched_scan_results(hw->wiphy);
907 }
908 EXPORT_SYMBOL(ieee80211_sched_scan_results);
909
ieee80211_sched_scan_stopped_work(struct work_struct * work)910 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
911 {
912 struct ieee80211_local *local =
913 container_of(work, struct ieee80211_local,
914 sched_scan_stopped_work);
915 int i;
916
917 mutex_lock(&local->mtx);
918
919 if (!local->sched_scanning) {
920 mutex_unlock(&local->mtx);
921 return;
922 }
923
924 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
925 kfree(local->sched_scan_ies.ie[i]);
926
927 local->sched_scanning = false;
928
929 mutex_unlock(&local->mtx);
930
931 cfg80211_sched_scan_stopped(local->hw.wiphy);
932 }
933
ieee80211_sched_scan_stopped(struct ieee80211_hw * hw)934 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
935 {
936 struct ieee80211_local *local = hw_to_local(hw);
937
938 trace_api_sched_scan_stopped(local);
939
940 ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
941 }
942 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
943