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 * Copyright 2013-2014 Intel Mobile Communications GmbH
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 */
15
16 #include <linux/if_arp.h>
17 #include <linux/etherdevice.h>
18 #include <linux/rtnetlink.h>
19 #include <linux/pm_qos.h>
20 #include <net/sch_generic.h>
21 #include <linux/slab.h>
22 #include <linux/export.h>
23 #include <net/mac80211.h>
24
25 #include "ieee80211_i.h"
26 #include "driver-ops.h"
27 #include "mesh.h"
28
29 #define IEEE80211_PROBE_DELAY (HZ / 33)
30 #define IEEE80211_CHANNEL_TIME (HZ / 33)
31 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
32
ieee80211_rx_bss_put(struct ieee80211_local * local,struct ieee80211_bss * bss)33 void ieee80211_rx_bss_put(struct ieee80211_local *local,
34 struct ieee80211_bss *bss)
35 {
36 if (!bss)
37 return;
38 cfg80211_put_bss(local->hw.wiphy,
39 container_of((void *)bss, struct cfg80211_bss, priv));
40 }
41
is_uapsd_supported(struct ieee802_11_elems * elems)42 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
43 {
44 u8 qos_info;
45
46 if (elems->wmm_info && elems->wmm_info_len == 7
47 && elems->wmm_info[5] == 1)
48 qos_info = elems->wmm_info[6];
49 else if (elems->wmm_param && elems->wmm_param_len == 24
50 && elems->wmm_param[5] == 1)
51 qos_info = elems->wmm_param[6];
52 else
53 /* no valid wmm information or parameter element found */
54 return false;
55
56 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
57 }
58
59 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)60 ieee80211_bss_info_update(struct ieee80211_local *local,
61 struct ieee80211_rx_status *rx_status,
62 struct ieee80211_mgmt *mgmt, size_t len,
63 struct ieee802_11_elems *elems,
64 struct ieee80211_channel *channel)
65 {
66 bool beacon = ieee80211_is_beacon(mgmt->frame_control);
67 struct cfg80211_bss *cbss;
68 struct ieee80211_bss *bss;
69 int clen, srlen;
70 enum nl80211_bss_scan_width scan_width;
71 s32 signal = 0;
72
73 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
74 signal = rx_status->signal * 100;
75 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
76 signal = (rx_status->signal * 100) / local->hw.max_signal;
77
78 scan_width = NL80211_BSS_CHAN_WIDTH_20;
79 if (rx_status->flag & RX_FLAG_5MHZ)
80 scan_width = NL80211_BSS_CHAN_WIDTH_5;
81 if (rx_status->flag & RX_FLAG_10MHZ)
82 scan_width = NL80211_BSS_CHAN_WIDTH_10;
83
84 cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel,
85 scan_width, mgmt, len, signal,
86 GFP_ATOMIC);
87 if (!cbss)
88 return NULL;
89
90 bss = (void *)cbss->priv;
91
92 if (beacon)
93 bss->device_ts_beacon = rx_status->device_timestamp;
94 else
95 bss->device_ts_presp = rx_status->device_timestamp;
96
97 if (elems->parse_error) {
98 if (beacon)
99 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
100 else
101 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
102 } else {
103 if (beacon)
104 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
105 else
106 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
107 }
108
109 /* save the ERP value so that it is available at association time */
110 if (elems->erp_info && (!elems->parse_error ||
111 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
112 bss->erp_value = elems->erp_info[0];
113 bss->has_erp_value = true;
114 if (!elems->parse_error)
115 bss->valid_data |= IEEE80211_BSS_VALID_ERP;
116 }
117
118 /* replace old supported rates if we get new values */
119 if (!elems->parse_error ||
120 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
121 srlen = 0;
122 if (elems->supp_rates) {
123 clen = IEEE80211_MAX_SUPP_RATES;
124 if (clen > elems->supp_rates_len)
125 clen = elems->supp_rates_len;
126 memcpy(bss->supp_rates, elems->supp_rates, clen);
127 srlen += clen;
128 }
129 if (elems->ext_supp_rates) {
130 clen = IEEE80211_MAX_SUPP_RATES - srlen;
131 if (clen > elems->ext_supp_rates_len)
132 clen = elems->ext_supp_rates_len;
133 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
134 clen);
135 srlen += clen;
136 }
137 if (srlen) {
138 bss->supp_rates_len = srlen;
139 if (!elems->parse_error)
140 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
141 }
142 }
143
144 if (!elems->parse_error ||
145 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
146 bss->wmm_used = elems->wmm_param || elems->wmm_info;
147 bss->uapsd_supported = is_uapsd_supported(elems);
148 if (!elems->parse_error)
149 bss->valid_data |= IEEE80211_BSS_VALID_WMM;
150 }
151
152 if (beacon) {
153 struct ieee80211_supported_band *sband =
154 local->hw.wiphy->bands[rx_status->band];
155 if (!(rx_status->flag & RX_FLAG_HT) &&
156 !(rx_status->flag & RX_FLAG_VHT))
157 bss->beacon_rate =
158 &sband->bitrates[rx_status->rate_idx];
159 }
160
161 return bss;
162 }
163
ieee80211_scan_rx(struct ieee80211_local * local,struct sk_buff * skb)164 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
165 {
166 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
167 struct ieee80211_sub_if_data *sdata1, *sdata2;
168 struct ieee80211_mgmt *mgmt = (void *)skb->data;
169 struct ieee80211_bss *bss;
170 u8 *elements;
171 struct ieee80211_channel *channel;
172 size_t baselen;
173 struct ieee802_11_elems elems;
174
175 if (skb->len < 24 ||
176 (!ieee80211_is_probe_resp(mgmt->frame_control) &&
177 !ieee80211_is_beacon(mgmt->frame_control)))
178 return;
179
180 sdata1 = rcu_dereference(local->scan_sdata);
181 sdata2 = rcu_dereference(local->sched_scan_sdata);
182
183 if (likely(!sdata1 && !sdata2))
184 return;
185
186 if (ieee80211_is_probe_resp(mgmt->frame_control)) {
187 /* ignore ProbeResp to foreign address */
188 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
189 (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
190 return;
191
192 elements = mgmt->u.probe_resp.variable;
193 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
194 } else {
195 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
196 elements = mgmt->u.beacon.variable;
197 }
198
199 if (baselen > skb->len)
200 return;
201
202 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
203
204 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
205
206 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
207 return;
208
209 bss = ieee80211_bss_info_update(local, rx_status,
210 mgmt, skb->len, &elems,
211 channel);
212 if (bss)
213 ieee80211_rx_bss_put(local, bss);
214 }
215
216 static void
ieee80211_prepare_scan_chandef(struct cfg80211_chan_def * chandef,enum nl80211_bss_scan_width scan_width)217 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
218 enum nl80211_bss_scan_width scan_width)
219 {
220 memset(chandef, 0, sizeof(*chandef));
221 switch (scan_width) {
222 case NL80211_BSS_CHAN_WIDTH_5:
223 chandef->width = NL80211_CHAN_WIDTH_5;
224 break;
225 case NL80211_BSS_CHAN_WIDTH_10:
226 chandef->width = NL80211_CHAN_WIDTH_10;
227 break;
228 default:
229 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
230 break;
231 }
232 }
233
234 /* return false if no more work */
ieee80211_prep_hw_scan(struct ieee80211_local * local)235 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
236 {
237 struct cfg80211_scan_request *req = local->scan_req;
238 struct cfg80211_chan_def chandef;
239 u8 bands_used = 0;
240 int i, ielen, n_chans;
241
242 if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
243 return false;
244
245 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
246 for (i = 0; i < req->n_channels; i++) {
247 local->hw_scan_req->req.channels[i] = req->channels[i];
248 bands_used |= BIT(req->channels[i]->band);
249 }
250
251 n_chans = req->n_channels;
252 } else {
253 do {
254 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
255 return false;
256
257 n_chans = 0;
258
259 for (i = 0; i < req->n_channels; i++) {
260 if (req->channels[i]->band !=
261 local->hw_scan_band)
262 continue;
263 local->hw_scan_req->req.channels[n_chans] =
264 req->channels[i];
265 n_chans++;
266 bands_used |= BIT(req->channels[i]->band);
267 }
268
269 local->hw_scan_band++;
270 } while (!n_chans);
271 }
272
273 local->hw_scan_req->req.n_channels = n_chans;
274 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
275
276 ielen = ieee80211_build_preq_ies(local,
277 (u8 *)local->hw_scan_req->req.ie,
278 local->hw_scan_ies_bufsize,
279 &local->hw_scan_req->ies,
280 req->ie, req->ie_len,
281 bands_used, req->rates, &chandef);
282 local->hw_scan_req->req.ie_len = ielen;
283 local->hw_scan_req->req.no_cck = req->no_cck;
284
285 return true;
286 }
287
__ieee80211_scan_completed(struct ieee80211_hw * hw,bool aborted)288 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
289 {
290 struct ieee80211_local *local = hw_to_local(hw);
291 bool hw_scan = local->ops->hw_scan;
292 bool was_scanning = local->scanning;
293 struct ieee80211_sub_if_data *sdata;
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 (hw_scan && !aborted &&
310 !(local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) &&
311 ieee80211_prep_hw_scan(local)) {
312 int rc;
313
314 rc = drv_hw_scan(local,
315 rcu_dereference_protected(local->scan_sdata,
316 lockdep_is_held(&local->mtx)),
317 local->hw_scan_req);
318
319 if (rc == 0)
320 return;
321 }
322
323 kfree(local->hw_scan_req);
324 local->hw_scan_req = NULL;
325
326 if (local->scan_req != local->int_scan_req)
327 cfg80211_scan_done(local->scan_req, aborted);
328 local->scan_req = NULL;
329 RCU_INIT_POINTER(local->scan_sdata, NULL);
330
331 local->scanning = 0;
332 local->scan_chandef.chan = NULL;
333
334 /* Set power back to normal operating levels. */
335 ieee80211_hw_config(local, 0);
336
337 if (!hw_scan) {
338 ieee80211_configure_filter(local);
339 drv_sw_scan_complete(local);
340 ieee80211_offchannel_return(local);
341 }
342
343 ieee80211_recalc_idle(local);
344
345 ieee80211_mlme_notify_scan_completed(local);
346 ieee80211_ibss_notify_scan_completed(local);
347
348 /* Requeue all the work that might have been ignored while
349 * the scan was in progress; if there was none this will
350 * just be a no-op for the particular interface.
351 */
352 list_for_each_entry_rcu(sdata, &local->interfaces, list) {
353 if (ieee80211_sdata_running(sdata))
354 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
355 }
356
357 if (was_scanning)
358 ieee80211_start_next_roc(local);
359 }
360
ieee80211_scan_completed(struct ieee80211_hw * hw,bool aborted)361 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
362 {
363 struct ieee80211_local *local = hw_to_local(hw);
364
365 trace_api_scan_completed(local, aborted);
366
367 set_bit(SCAN_COMPLETED, &local->scanning);
368 if (aborted)
369 set_bit(SCAN_ABORTED, &local->scanning);
370 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
371 }
372 EXPORT_SYMBOL(ieee80211_scan_completed);
373
ieee80211_start_sw_scan(struct ieee80211_local * local)374 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
375 {
376 /* Software scan is not supported in multi-channel cases */
377 if (local->use_chanctx)
378 return -EOPNOTSUPP;
379
380 /*
381 * Hardware/driver doesn't support hw_scan, so use software
382 * scanning instead. First send a nullfunc frame with power save
383 * bit on so that AP will buffer the frames for us while we are not
384 * listening, then send probe requests to each channel and wait for
385 * the responses. After all channels are scanned, tune back to the
386 * original channel and send a nullfunc frame with power save bit
387 * off to trigger the AP to send us all the buffered frames.
388 *
389 * Note that while local->sw_scanning is true everything else but
390 * nullfunc frames and probe requests will be dropped in
391 * ieee80211_tx_h_check_assoc().
392 */
393 drv_sw_scan_start(local);
394
395 local->leave_oper_channel_time = jiffies;
396 local->next_scan_state = SCAN_DECISION;
397 local->scan_channel_idx = 0;
398
399 ieee80211_offchannel_stop_vifs(local);
400
401 /* ensure nullfunc is transmitted before leaving operating channel */
402 ieee80211_flush_queues(local, NULL);
403
404 ieee80211_configure_filter(local);
405
406 /* We need to set power level at maximum rate for scanning. */
407 ieee80211_hw_config(local, 0);
408
409 ieee80211_queue_delayed_work(&local->hw,
410 &local->scan_work, 0);
411
412 return 0;
413 }
414
ieee80211_can_scan(struct ieee80211_local * local,struct ieee80211_sub_if_data * sdata)415 static bool ieee80211_can_scan(struct ieee80211_local *local,
416 struct ieee80211_sub_if_data *sdata)
417 {
418 if (local->radar_detect_enabled)
419 return false;
420
421 if (!list_empty(&local->roc_list))
422 return false;
423
424 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
425 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
426 return false;
427
428 return true;
429 }
430
ieee80211_run_deferred_scan(struct ieee80211_local * local)431 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
432 {
433 lockdep_assert_held(&local->mtx);
434
435 if (!local->scan_req || local->scanning)
436 return;
437
438 if (!ieee80211_can_scan(local,
439 rcu_dereference_protected(
440 local->scan_sdata,
441 lockdep_is_held(&local->mtx))))
442 return;
443
444 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
445 round_jiffies_relative(0));
446 }
447
ieee80211_scan_state_send_probe(struct ieee80211_local * local,unsigned long * next_delay)448 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
449 unsigned long *next_delay)
450 {
451 int i;
452 struct ieee80211_sub_if_data *sdata;
453 enum ieee80211_band band = local->hw.conf.chandef.chan->band;
454 u32 tx_flags;
455
456 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
457 if (local->scan_req->no_cck)
458 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
459
460 sdata = rcu_dereference_protected(local->scan_sdata,
461 lockdep_is_held(&local->mtx));
462
463 for (i = 0; i < local->scan_req->n_ssids; i++)
464 ieee80211_send_probe_req(
465 sdata, NULL,
466 local->scan_req->ssids[i].ssid,
467 local->scan_req->ssids[i].ssid_len,
468 local->scan_req->ie, local->scan_req->ie_len,
469 local->scan_req->rates[band], false,
470 tx_flags, local->hw.conf.chandef.chan, true);
471
472 /*
473 * After sending probe requests, wait for probe responses
474 * on the channel.
475 */
476 *next_delay = IEEE80211_CHANNEL_TIME;
477 local->next_scan_state = SCAN_DECISION;
478 }
479
__ieee80211_start_scan(struct ieee80211_sub_if_data * sdata,struct cfg80211_scan_request * req)480 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
481 struct cfg80211_scan_request *req)
482 {
483 struct ieee80211_local *local = sdata->local;
484 int rc;
485
486 lockdep_assert_held(&local->mtx);
487
488 if (local->scan_req)
489 return -EBUSY;
490
491 if (!ieee80211_can_scan(local, sdata)) {
492 /* wait for the work to finish/time out */
493 local->scan_req = req;
494 rcu_assign_pointer(local->scan_sdata, sdata);
495 return 0;
496 }
497
498 if (local->ops->hw_scan) {
499 u8 *ies;
500
501 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
502
503 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
504 int i, n_bands = 0;
505 u8 bands_counted = 0;
506
507 for (i = 0; i < req->n_channels; i++) {
508 if (bands_counted & BIT(req->channels[i]->band))
509 continue;
510 bands_counted |= BIT(req->channels[i]->band);
511 n_bands++;
512 }
513
514 local->hw_scan_ies_bufsize *= n_bands;
515 }
516
517 local->hw_scan_req = kmalloc(
518 sizeof(*local->hw_scan_req) +
519 req->n_channels * sizeof(req->channels[0]) +
520 local->hw_scan_ies_bufsize, GFP_KERNEL);
521 if (!local->hw_scan_req)
522 return -ENOMEM;
523
524 local->hw_scan_req->req.ssids = req->ssids;
525 local->hw_scan_req->req.n_ssids = req->n_ssids;
526 ies = (u8 *)local->hw_scan_req +
527 sizeof(*local->hw_scan_req) +
528 req->n_channels * sizeof(req->channels[0]);
529 local->hw_scan_req->req.ie = ies;
530 local->hw_scan_req->req.flags = req->flags;
531
532 local->hw_scan_band = 0;
533
534 /*
535 * After allocating local->hw_scan_req, we must
536 * go through until ieee80211_prep_hw_scan(), so
537 * anything that might be changed here and leave
538 * this function early must not go after this
539 * allocation.
540 */
541 }
542
543 local->scan_req = req;
544 rcu_assign_pointer(local->scan_sdata, sdata);
545
546 if (local->ops->hw_scan) {
547 __set_bit(SCAN_HW_SCANNING, &local->scanning);
548 } else if ((req->n_channels == 1) &&
549 (req->channels[0] == local->_oper_chandef.chan)) {
550 /*
551 * If we are scanning only on the operating channel
552 * then we do not need to stop normal activities
553 */
554 unsigned long next_delay;
555
556 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
557
558 ieee80211_recalc_idle(local);
559
560 /* Notify driver scan is starting, keep order of operations
561 * same as normal software scan, in case that matters. */
562 drv_sw_scan_start(local);
563
564 ieee80211_configure_filter(local); /* accept probe-responses */
565
566 /* We need to ensure power level is at max for scanning. */
567 ieee80211_hw_config(local, 0);
568
569 if ((req->channels[0]->flags &
570 IEEE80211_CHAN_NO_IR) ||
571 !local->scan_req->n_ssids) {
572 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
573 } else {
574 ieee80211_scan_state_send_probe(local, &next_delay);
575 next_delay = IEEE80211_CHANNEL_TIME;
576 }
577
578 /* Now, just wait a bit and we are all done! */
579 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
580 next_delay);
581 return 0;
582 } else {
583 /* Do normal software scan */
584 __set_bit(SCAN_SW_SCANNING, &local->scanning);
585 }
586
587 ieee80211_recalc_idle(local);
588
589 if (local->ops->hw_scan) {
590 WARN_ON(!ieee80211_prep_hw_scan(local));
591 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
592 } else
593 rc = ieee80211_start_sw_scan(local);
594
595 if (rc) {
596 kfree(local->hw_scan_req);
597 local->hw_scan_req = NULL;
598 local->scanning = 0;
599
600 ieee80211_recalc_idle(local);
601
602 local->scan_req = NULL;
603 RCU_INIT_POINTER(local->scan_sdata, NULL);
604 }
605
606 return rc;
607 }
608
609 static unsigned long
ieee80211_scan_get_channel_time(struct ieee80211_channel * chan)610 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
611 {
612 /*
613 * TODO: channel switching also consumes quite some time,
614 * add that delay as well to get a better estimation
615 */
616 if (chan->flags & IEEE80211_CHAN_NO_IR)
617 return IEEE80211_PASSIVE_CHANNEL_TIME;
618 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
619 }
620
ieee80211_scan_state_decision(struct ieee80211_local * local,unsigned long * next_delay)621 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
622 unsigned long *next_delay)
623 {
624 bool associated = false;
625 bool tx_empty = true;
626 bool bad_latency;
627 struct ieee80211_sub_if_data *sdata;
628 struct ieee80211_channel *next_chan;
629 enum mac80211_scan_state next_scan_state;
630
631 /*
632 * check if at least one STA interface is associated,
633 * check if at least one STA interface has pending tx frames
634 * and grab the lowest used beacon interval
635 */
636 mutex_lock(&local->iflist_mtx);
637 list_for_each_entry(sdata, &local->interfaces, list) {
638 if (!ieee80211_sdata_running(sdata))
639 continue;
640
641 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
642 if (sdata->u.mgd.associated) {
643 associated = true;
644
645 if (!qdisc_all_tx_empty(sdata->dev)) {
646 tx_empty = false;
647 break;
648 }
649 }
650 }
651 }
652 mutex_unlock(&local->iflist_mtx);
653
654 next_chan = local->scan_req->channels[local->scan_channel_idx];
655
656 /*
657 * we're currently scanning a different channel, let's
658 * see if we can scan another channel without interfering
659 * with the current traffic situation.
660 *
661 * Keep good latency, do not stay off-channel more than 125 ms.
662 */
663
664 bad_latency = time_after(jiffies +
665 ieee80211_scan_get_channel_time(next_chan),
666 local->leave_oper_channel_time + HZ / 8);
667
668 if (associated && !tx_empty) {
669 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
670 next_scan_state = SCAN_ABORT;
671 else
672 next_scan_state = SCAN_SUSPEND;
673 } else if (associated && bad_latency) {
674 next_scan_state = SCAN_SUSPEND;
675 } else {
676 next_scan_state = SCAN_SET_CHANNEL;
677 }
678
679 local->next_scan_state = next_scan_state;
680
681 *next_delay = 0;
682 }
683
ieee80211_scan_state_set_channel(struct ieee80211_local * local,unsigned long * next_delay)684 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
685 unsigned long *next_delay)
686 {
687 int skip;
688 struct ieee80211_channel *chan;
689 enum nl80211_bss_scan_width oper_scan_width;
690
691 skip = 0;
692 chan = local->scan_req->channels[local->scan_channel_idx];
693
694 local->scan_chandef.chan = chan;
695 local->scan_chandef.center_freq1 = chan->center_freq;
696 local->scan_chandef.center_freq2 = 0;
697 switch (local->scan_req->scan_width) {
698 case NL80211_BSS_CHAN_WIDTH_5:
699 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
700 break;
701 case NL80211_BSS_CHAN_WIDTH_10:
702 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
703 break;
704 case NL80211_BSS_CHAN_WIDTH_20:
705 /* If scanning on oper channel, use whatever channel-type
706 * is currently in use.
707 */
708 oper_scan_width = cfg80211_chandef_to_scan_width(
709 &local->_oper_chandef);
710 if (chan == local->_oper_chandef.chan &&
711 oper_scan_width == local->scan_req->scan_width)
712 local->scan_chandef = local->_oper_chandef;
713 else
714 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
715 break;
716 }
717
718 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
719 skip = 1;
720
721 /* advance state machine to next channel/band */
722 local->scan_channel_idx++;
723
724 if (skip) {
725 /* if we skip this channel return to the decision state */
726 local->next_scan_state = SCAN_DECISION;
727 return;
728 }
729
730 /*
731 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
732 * (which unfortunately doesn't say _why_ step a) is done,
733 * but it waits for the probe delay or until a frame is
734 * received - and the received frame would update the NAV).
735 * For now, we do not support waiting until a frame is
736 * received.
737 *
738 * In any case, it is not necessary for a passive scan.
739 */
740 if (chan->flags & IEEE80211_CHAN_NO_IR ||
741 !local->scan_req->n_ssids) {
742 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
743 local->next_scan_state = SCAN_DECISION;
744 return;
745 }
746
747 /* active scan, send probes */
748 *next_delay = IEEE80211_PROBE_DELAY;
749 local->next_scan_state = SCAN_SEND_PROBE;
750 }
751
ieee80211_scan_state_suspend(struct ieee80211_local * local,unsigned long * next_delay)752 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
753 unsigned long *next_delay)
754 {
755 /* switch back to the operating channel */
756 local->scan_chandef.chan = NULL;
757 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
758
759 /* disable PS */
760 ieee80211_offchannel_return(local);
761
762 *next_delay = HZ / 5;
763 /* afterwards, resume scan & go to next channel */
764 local->next_scan_state = SCAN_RESUME;
765 }
766
ieee80211_scan_state_resume(struct ieee80211_local * local,unsigned long * next_delay)767 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
768 unsigned long *next_delay)
769 {
770 ieee80211_offchannel_stop_vifs(local);
771
772 if (local->ops->flush) {
773 ieee80211_flush_queues(local, NULL);
774 *next_delay = 0;
775 } else
776 *next_delay = HZ / 10;
777
778 /* remember when we left the operating channel */
779 local->leave_oper_channel_time = jiffies;
780
781 /* advance to the next channel to be scanned */
782 local->next_scan_state = SCAN_SET_CHANNEL;
783 }
784
ieee80211_scan_work(struct work_struct * work)785 void ieee80211_scan_work(struct work_struct *work)
786 {
787 struct ieee80211_local *local =
788 container_of(work, struct ieee80211_local, scan_work.work);
789 struct ieee80211_sub_if_data *sdata;
790 unsigned long next_delay = 0;
791 bool aborted;
792
793 mutex_lock(&local->mtx);
794
795 sdata = rcu_dereference_protected(local->scan_sdata,
796 lockdep_is_held(&local->mtx));
797
798 /* When scanning on-channel, the first-callback means completed. */
799 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
800 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
801 goto out_complete;
802 }
803
804 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
805 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
806 goto out_complete;
807 }
808
809 if (!sdata || !local->scan_req)
810 goto out;
811
812 if (local->scan_req && !local->scanning) {
813 struct cfg80211_scan_request *req = local->scan_req;
814 int rc;
815
816 local->scan_req = NULL;
817 RCU_INIT_POINTER(local->scan_sdata, NULL);
818
819 rc = __ieee80211_start_scan(sdata, req);
820 if (rc) {
821 /* need to complete scan in cfg80211 */
822 local->scan_req = req;
823 aborted = true;
824 goto out_complete;
825 } else
826 goto out;
827 }
828
829 /*
830 * as long as no delay is required advance immediately
831 * without scheduling a new work
832 */
833 do {
834 if (!ieee80211_sdata_running(sdata)) {
835 aborted = true;
836 goto out_complete;
837 }
838
839 switch (local->next_scan_state) {
840 case SCAN_DECISION:
841 /* if no more bands/channels left, complete scan */
842 if (local->scan_channel_idx >= local->scan_req->n_channels) {
843 aborted = false;
844 goto out_complete;
845 }
846 ieee80211_scan_state_decision(local, &next_delay);
847 break;
848 case SCAN_SET_CHANNEL:
849 ieee80211_scan_state_set_channel(local, &next_delay);
850 break;
851 case SCAN_SEND_PROBE:
852 ieee80211_scan_state_send_probe(local, &next_delay);
853 break;
854 case SCAN_SUSPEND:
855 ieee80211_scan_state_suspend(local, &next_delay);
856 break;
857 case SCAN_RESUME:
858 ieee80211_scan_state_resume(local, &next_delay);
859 break;
860 case SCAN_ABORT:
861 aborted = true;
862 goto out_complete;
863 }
864 } while (next_delay == 0);
865
866 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
867 goto out;
868
869 out_complete:
870 __ieee80211_scan_completed(&local->hw, aborted);
871 out:
872 mutex_unlock(&local->mtx);
873 }
874
ieee80211_request_scan(struct ieee80211_sub_if_data * sdata,struct cfg80211_scan_request * req)875 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
876 struct cfg80211_scan_request *req)
877 {
878 int res;
879
880 mutex_lock(&sdata->local->mtx);
881 res = __ieee80211_start_scan(sdata, req);
882 mutex_unlock(&sdata->local->mtx);
883
884 return res;
885 }
886
ieee80211_request_ibss_scan(struct ieee80211_sub_if_data * sdata,const u8 * ssid,u8 ssid_len,struct ieee80211_channel * chan,enum nl80211_bss_scan_width scan_width)887 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
888 const u8 *ssid, u8 ssid_len,
889 struct ieee80211_channel *chan,
890 enum nl80211_bss_scan_width scan_width)
891 {
892 struct ieee80211_local *local = sdata->local;
893 int ret = -EBUSY;
894 enum ieee80211_band band;
895
896 mutex_lock(&local->mtx);
897
898 /* busy scanning */
899 if (local->scan_req)
900 goto unlock;
901
902 /* fill internal scan request */
903 if (!chan) {
904 int i, max_n;
905 int n_ch = 0;
906
907 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
908 if (!local->hw.wiphy->bands[band])
909 continue;
910
911 max_n = local->hw.wiphy->bands[band]->n_channels;
912 for (i = 0; i < max_n; i++) {
913 struct ieee80211_channel *tmp_ch =
914 &local->hw.wiphy->bands[band]->channels[i];
915
916 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
917 IEEE80211_CHAN_DISABLED))
918 continue;
919
920 local->int_scan_req->channels[n_ch] = tmp_ch;
921 n_ch++;
922 }
923 }
924
925 if (WARN_ON_ONCE(n_ch == 0))
926 goto unlock;
927
928 local->int_scan_req->n_channels = n_ch;
929 } else {
930 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR |
931 IEEE80211_CHAN_DISABLED)))
932 goto unlock;
933
934 local->int_scan_req->channels[0] = chan;
935 local->int_scan_req->n_channels = 1;
936 }
937
938 local->int_scan_req->ssids = &local->scan_ssid;
939 local->int_scan_req->n_ssids = 1;
940 local->int_scan_req->scan_width = scan_width;
941 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
942 local->int_scan_req->ssids[0].ssid_len = ssid_len;
943
944 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
945 unlock:
946 mutex_unlock(&local->mtx);
947 return ret;
948 }
949
950 /*
951 * Only call this function when a scan can't be queued -- under RTNL.
952 */
ieee80211_scan_cancel(struct ieee80211_local * local)953 void ieee80211_scan_cancel(struct ieee80211_local *local)
954 {
955 /*
956 * We are canceling software scan, or deferred scan that was not
957 * yet really started (see __ieee80211_start_scan ).
958 *
959 * Regarding hardware scan:
960 * - we can not call __ieee80211_scan_completed() as when
961 * SCAN_HW_SCANNING bit is set this function change
962 * local->hw_scan_req to operate on 5G band, what race with
963 * driver which can use local->hw_scan_req
964 *
965 * - we can not cancel scan_work since driver can schedule it
966 * by ieee80211_scan_completed(..., true) to finish scan
967 *
968 * Hence we only call the cancel_hw_scan() callback, but the low-level
969 * driver is still responsible for calling ieee80211_scan_completed()
970 * after the scan was completed/aborted.
971 */
972
973 mutex_lock(&local->mtx);
974 if (!local->scan_req)
975 goto out;
976
977 /*
978 * We have a scan running and the driver already reported completion,
979 * but the worker hasn't run yet or is stuck on the mutex - mark it as
980 * cancelled.
981 */
982 if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
983 test_bit(SCAN_COMPLETED, &local->scanning)) {
984 set_bit(SCAN_HW_CANCELLED, &local->scanning);
985 goto out;
986 }
987
988 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
989 /*
990 * Make sure that __ieee80211_scan_completed doesn't trigger a
991 * scan on another band.
992 */
993 set_bit(SCAN_HW_CANCELLED, &local->scanning);
994 if (local->ops->cancel_hw_scan)
995 drv_cancel_hw_scan(local,
996 rcu_dereference_protected(local->scan_sdata,
997 lockdep_is_held(&local->mtx)));
998 goto out;
999 }
1000
1001 /*
1002 * If the work is currently running, it must be blocked on
1003 * the mutex, but we'll set scan_sdata = NULL and it'll
1004 * simply exit once it acquires the mutex.
1005 */
1006 cancel_delayed_work(&local->scan_work);
1007 /* and clean up */
1008 __ieee80211_scan_completed(&local->hw, true);
1009 out:
1010 mutex_unlock(&local->mtx);
1011 }
1012
__ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data * sdata,struct cfg80211_sched_scan_request * req)1013 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1014 struct cfg80211_sched_scan_request *req)
1015 {
1016 struct ieee80211_local *local = sdata->local;
1017 struct ieee80211_scan_ies sched_scan_ies = {};
1018 struct cfg80211_chan_def chandef;
1019 int ret, i, iebufsz, num_bands = 0;
1020 u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1021 u8 bands_used = 0;
1022 u8 *ie;
1023 size_t len;
1024
1025 iebufsz = local->scan_ies_len + req->ie_len;
1026
1027 lockdep_assert_held(&local->mtx);
1028
1029 if (!local->ops->sched_scan_start)
1030 return -ENOTSUPP;
1031
1032 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1033 if (local->hw.wiphy->bands[i]) {
1034 bands_used |= BIT(i);
1035 rate_masks[i] = (u32) -1;
1036 num_bands++;
1037 }
1038 }
1039
1040 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1041 if (!ie) {
1042 ret = -ENOMEM;
1043 goto out;
1044 }
1045
1046 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1047
1048 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1049 &sched_scan_ies, req->ie,
1050 req->ie_len, bands_used,
1051 rate_masks, &chandef);
1052
1053 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1054 if (ret == 0) {
1055 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1056 local->sched_scan_req = req;
1057 }
1058
1059 kfree(ie);
1060
1061 out:
1062 if (ret) {
1063 /* Clean in case of failure after HW restart or upon resume. */
1064 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1065 local->sched_scan_req = NULL;
1066 }
1067
1068 return ret;
1069 }
1070
ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data * sdata,struct cfg80211_sched_scan_request * req)1071 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1072 struct cfg80211_sched_scan_request *req)
1073 {
1074 struct ieee80211_local *local = sdata->local;
1075 int ret;
1076
1077 mutex_lock(&local->mtx);
1078
1079 if (rcu_access_pointer(local->sched_scan_sdata)) {
1080 mutex_unlock(&local->mtx);
1081 return -EBUSY;
1082 }
1083
1084 ret = __ieee80211_request_sched_scan_start(sdata, req);
1085
1086 mutex_unlock(&local->mtx);
1087 return ret;
1088 }
1089
ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data * sdata)1090 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1091 {
1092 struct ieee80211_local *local = sdata->local;
1093 int ret = 0;
1094
1095 mutex_lock(&local->mtx);
1096
1097 if (!local->ops->sched_scan_stop) {
1098 ret = -ENOTSUPP;
1099 goto out;
1100 }
1101
1102 /* We don't want to restart sched scan anymore. */
1103 local->sched_scan_req = NULL;
1104
1105 if (rcu_access_pointer(local->sched_scan_sdata)) {
1106 ret = drv_sched_scan_stop(local, sdata);
1107 if (!ret)
1108 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1109 }
1110 out:
1111 mutex_unlock(&local->mtx);
1112
1113 return ret;
1114 }
1115
ieee80211_sched_scan_results(struct ieee80211_hw * hw)1116 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1117 {
1118 struct ieee80211_local *local = hw_to_local(hw);
1119
1120 trace_api_sched_scan_results(local);
1121
1122 cfg80211_sched_scan_results(hw->wiphy);
1123 }
1124 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1125
ieee80211_sched_scan_end(struct ieee80211_local * local)1126 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1127 {
1128 mutex_lock(&local->mtx);
1129
1130 if (!rcu_access_pointer(local->sched_scan_sdata)) {
1131 mutex_unlock(&local->mtx);
1132 return;
1133 }
1134
1135 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1136
1137 /* If sched scan was aborted by the driver. */
1138 local->sched_scan_req = NULL;
1139
1140 mutex_unlock(&local->mtx);
1141
1142 cfg80211_sched_scan_stopped(local->hw.wiphy);
1143 }
1144
ieee80211_sched_scan_stopped_work(struct work_struct * work)1145 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1146 {
1147 struct ieee80211_local *local =
1148 container_of(work, struct ieee80211_local,
1149 sched_scan_stopped_work);
1150
1151 ieee80211_sched_scan_end(local);
1152 }
1153
ieee80211_sched_scan_stopped(struct ieee80211_hw * hw)1154 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1155 {
1156 struct ieee80211_local *local = hw_to_local(hw);
1157
1158 trace_api_sched_scan_stopped(local);
1159
1160 schedule_work(&local->sched_scan_stopped_work);
1161 }
1162 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1163