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Merge branch 'aarch64/kvm-bounce-page' into aarch64/for-next/core
[deliverable/linux.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 * 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
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
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 *
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
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 struct cfg80211_scan_request *scan_req;
188 struct cfg80211_sched_scan_request *sched_scan_req;
189
190 scan_req = rcu_dereference(local->scan_req);
191 sched_scan_req = rcu_dereference(local->sched_scan_req);
192
193 /* ignore ProbeResp to foreign address unless scanning
194 * with randomised address
195 */
196 if (!(sdata1 &&
197 (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
198 scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
199 !(sdata2 &&
200 (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
201 sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
202 return;
203
204 elements = mgmt->u.probe_resp.variable;
205 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
206 } else {
207 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
208 elements = mgmt->u.beacon.variable;
209 }
210
211 if (baselen > skb->len)
212 return;
213
214 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
215
216 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
217
218 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
219 return;
220
221 bss = ieee80211_bss_info_update(local, rx_status,
222 mgmt, skb->len, &elems,
223 channel);
224 if (bss)
225 ieee80211_rx_bss_put(local, bss);
226 }
227
228 static void
229 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
230 enum nl80211_bss_scan_width scan_width)
231 {
232 memset(chandef, 0, sizeof(*chandef));
233 switch (scan_width) {
234 case NL80211_BSS_CHAN_WIDTH_5:
235 chandef->width = NL80211_CHAN_WIDTH_5;
236 break;
237 case NL80211_BSS_CHAN_WIDTH_10:
238 chandef->width = NL80211_CHAN_WIDTH_10;
239 break;
240 default:
241 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
242 break;
243 }
244 }
245
246 /* return false if no more work */
247 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
248 {
249 struct cfg80211_scan_request *req;
250 struct cfg80211_chan_def chandef;
251 u8 bands_used = 0;
252 int i, ielen, n_chans;
253
254 req = rcu_dereference_protected(local->scan_req,
255 lockdep_is_held(&local->mtx));
256
257 if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
258 return false;
259
260 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
261 for (i = 0; i < req->n_channels; i++) {
262 local->hw_scan_req->req.channels[i] = req->channels[i];
263 bands_used |= BIT(req->channels[i]->band);
264 }
265
266 n_chans = req->n_channels;
267 } else {
268 do {
269 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
270 return false;
271
272 n_chans = 0;
273
274 for (i = 0; i < req->n_channels; i++) {
275 if (req->channels[i]->band !=
276 local->hw_scan_band)
277 continue;
278 local->hw_scan_req->req.channels[n_chans] =
279 req->channels[i];
280 n_chans++;
281 bands_used |= BIT(req->channels[i]->band);
282 }
283
284 local->hw_scan_band++;
285 } while (!n_chans);
286 }
287
288 local->hw_scan_req->req.n_channels = n_chans;
289 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
290
291 ielen = ieee80211_build_preq_ies(local,
292 (u8 *)local->hw_scan_req->req.ie,
293 local->hw_scan_ies_bufsize,
294 &local->hw_scan_req->ies,
295 req->ie, req->ie_len,
296 bands_used, req->rates, &chandef);
297 local->hw_scan_req->req.ie_len = ielen;
298 local->hw_scan_req->req.no_cck = req->no_cck;
299 ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
300 ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
301 req->mac_addr_mask);
302
303 return true;
304 }
305
306 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
307 {
308 struct ieee80211_local *local = hw_to_local(hw);
309 bool hw_scan = local->ops->hw_scan;
310 bool was_scanning = local->scanning;
311 struct cfg80211_scan_request *scan_req;
312 struct ieee80211_sub_if_data *scan_sdata;
313
314 lockdep_assert_held(&local->mtx);
315
316 /*
317 * It's ok to abort a not-yet-running scan (that
318 * we have one at all will be verified by checking
319 * local->scan_req next), but not to complete it
320 * successfully.
321 */
322 if (WARN_ON(!local->scanning && !aborted))
323 aborted = true;
324
325 if (WARN_ON(!local->scan_req))
326 return;
327
328 if (hw_scan && !aborted &&
329 !(local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) &&
330 ieee80211_prep_hw_scan(local)) {
331 int rc;
332
333 rc = drv_hw_scan(local,
334 rcu_dereference_protected(local->scan_sdata,
335 lockdep_is_held(&local->mtx)),
336 local->hw_scan_req);
337
338 if (rc == 0)
339 return;
340 }
341
342 kfree(local->hw_scan_req);
343 local->hw_scan_req = NULL;
344
345 scan_req = rcu_dereference_protected(local->scan_req,
346 lockdep_is_held(&local->mtx));
347
348 if (scan_req != local->int_scan_req)
349 cfg80211_scan_done(scan_req, aborted);
350 RCU_INIT_POINTER(local->scan_req, NULL);
351
352 scan_sdata = rcu_dereference_protected(local->scan_sdata,
353 lockdep_is_held(&local->mtx));
354 RCU_INIT_POINTER(local->scan_sdata, NULL);
355
356 local->scanning = 0;
357 local->scan_chandef.chan = NULL;
358
359 /* Set power back to normal operating levels. */
360 ieee80211_hw_config(local, 0);
361
362 if (!hw_scan) {
363 ieee80211_configure_filter(local);
364 drv_sw_scan_complete(local, scan_sdata);
365 ieee80211_offchannel_return(local);
366 }
367
368 ieee80211_recalc_idle(local);
369
370 ieee80211_mlme_notify_scan_completed(local);
371 ieee80211_ibss_notify_scan_completed(local);
372 ieee80211_mesh_notify_scan_completed(local);
373 if (was_scanning)
374 ieee80211_start_next_roc(local);
375 }
376
377 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
378 {
379 struct ieee80211_local *local = hw_to_local(hw);
380
381 trace_api_scan_completed(local, aborted);
382
383 set_bit(SCAN_COMPLETED, &local->scanning);
384 if (aborted)
385 set_bit(SCAN_ABORTED, &local->scanning);
386 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
387 }
388 EXPORT_SYMBOL(ieee80211_scan_completed);
389
390 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
391 struct ieee80211_sub_if_data *sdata)
392 {
393 /* Software scan is not supported in multi-channel cases */
394 if (local->use_chanctx)
395 return -EOPNOTSUPP;
396
397 /*
398 * Hardware/driver doesn't support hw_scan, so use software
399 * scanning instead. First send a nullfunc frame with power save
400 * bit on so that AP will buffer the frames for us while we are not
401 * listening, then send probe requests to each channel and wait for
402 * the responses. After all channels are scanned, tune back to the
403 * original channel and send a nullfunc frame with power save bit
404 * off to trigger the AP to send us all the buffered frames.
405 *
406 * Note that while local->sw_scanning is true everything else but
407 * nullfunc frames and probe requests will be dropped in
408 * ieee80211_tx_h_check_assoc().
409 */
410 drv_sw_scan_start(local, sdata, local->scan_addr);
411
412 local->leave_oper_channel_time = jiffies;
413 local->next_scan_state = SCAN_DECISION;
414 local->scan_channel_idx = 0;
415
416 ieee80211_offchannel_stop_vifs(local);
417
418 /* ensure nullfunc is transmitted before leaving operating channel */
419 ieee80211_flush_queues(local, NULL, false);
420
421 ieee80211_configure_filter(local);
422
423 /* We need to set power level at maximum rate for scanning. */
424 ieee80211_hw_config(local, 0);
425
426 ieee80211_queue_delayed_work(&local->hw,
427 &local->scan_work, 0);
428
429 return 0;
430 }
431
432 static bool ieee80211_can_scan(struct ieee80211_local *local,
433 struct ieee80211_sub_if_data *sdata)
434 {
435 if (ieee80211_is_radar_required(local))
436 return false;
437
438 if (!list_empty(&local->roc_list))
439 return false;
440
441 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
442 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
443 return false;
444
445 return true;
446 }
447
448 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
449 {
450 lockdep_assert_held(&local->mtx);
451
452 if (!local->scan_req || local->scanning)
453 return;
454
455 if (!ieee80211_can_scan(local,
456 rcu_dereference_protected(
457 local->scan_sdata,
458 lockdep_is_held(&local->mtx))))
459 return;
460
461 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
462 round_jiffies_relative(0));
463 }
464
465 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
466 unsigned long *next_delay)
467 {
468 int i;
469 struct ieee80211_sub_if_data *sdata;
470 struct cfg80211_scan_request *scan_req;
471 enum ieee80211_band band = local->hw.conf.chandef.chan->band;
472 u32 tx_flags;
473
474 scan_req = rcu_dereference_protected(local->scan_req,
475 lockdep_is_held(&local->mtx));
476
477 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
478 if (scan_req->no_cck)
479 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
480
481 sdata = rcu_dereference_protected(local->scan_sdata,
482 lockdep_is_held(&local->mtx));
483
484 for (i = 0; i < scan_req->n_ssids; i++)
485 ieee80211_send_probe_req(
486 sdata, local->scan_addr, NULL,
487 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
488 scan_req->ie, scan_req->ie_len,
489 scan_req->rates[band], false,
490 tx_flags, local->hw.conf.chandef.chan, true);
491
492 /*
493 * After sending probe requests, wait for probe responses
494 * on the channel.
495 */
496 *next_delay = IEEE80211_CHANNEL_TIME;
497 local->next_scan_state = SCAN_DECISION;
498 }
499
500 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
501 struct cfg80211_scan_request *req)
502 {
503 struct ieee80211_local *local = sdata->local;
504 int rc;
505
506 lockdep_assert_held(&local->mtx);
507
508 if (local->scan_req || ieee80211_is_radar_required(local))
509 return -EBUSY;
510
511 if (!ieee80211_can_scan(local, sdata)) {
512 /* wait for the work to finish/time out */
513 rcu_assign_pointer(local->scan_req, req);
514 rcu_assign_pointer(local->scan_sdata, sdata);
515 return 0;
516 }
517
518 if (local->ops->hw_scan) {
519 u8 *ies;
520
521 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
522
523 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
524 int i, n_bands = 0;
525 u8 bands_counted = 0;
526
527 for (i = 0; i < req->n_channels; i++) {
528 if (bands_counted & BIT(req->channels[i]->band))
529 continue;
530 bands_counted |= BIT(req->channels[i]->band);
531 n_bands++;
532 }
533
534 local->hw_scan_ies_bufsize *= n_bands;
535 }
536
537 local->hw_scan_req = kmalloc(
538 sizeof(*local->hw_scan_req) +
539 req->n_channels * sizeof(req->channels[0]) +
540 local->hw_scan_ies_bufsize, GFP_KERNEL);
541 if (!local->hw_scan_req)
542 return -ENOMEM;
543
544 local->hw_scan_req->req.ssids = req->ssids;
545 local->hw_scan_req->req.n_ssids = req->n_ssids;
546 ies = (u8 *)local->hw_scan_req +
547 sizeof(*local->hw_scan_req) +
548 req->n_channels * sizeof(req->channels[0]);
549 local->hw_scan_req->req.ie = ies;
550 local->hw_scan_req->req.flags = req->flags;
551
552 local->hw_scan_band = 0;
553
554 /*
555 * After allocating local->hw_scan_req, we must
556 * go through until ieee80211_prep_hw_scan(), so
557 * anything that might be changed here and leave
558 * this function early must not go after this
559 * allocation.
560 */
561 }
562
563 rcu_assign_pointer(local->scan_req, req);
564 rcu_assign_pointer(local->scan_sdata, sdata);
565
566 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
567 get_random_mask_addr(local->scan_addr,
568 req->mac_addr,
569 req->mac_addr_mask);
570 else
571 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
572
573 if (local->ops->hw_scan) {
574 __set_bit(SCAN_HW_SCANNING, &local->scanning);
575 } else if ((req->n_channels == 1) &&
576 (req->channels[0] == local->_oper_chandef.chan)) {
577 /*
578 * If we are scanning only on the operating channel
579 * then we do not need to stop normal activities
580 */
581 unsigned long next_delay;
582
583 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
584
585 ieee80211_recalc_idle(local);
586
587 /* Notify driver scan is starting, keep order of operations
588 * same as normal software scan, in case that matters. */
589 drv_sw_scan_start(local, sdata, local->scan_addr);
590
591 ieee80211_configure_filter(local); /* accept probe-responses */
592
593 /* We need to ensure power level is at max for scanning. */
594 ieee80211_hw_config(local, 0);
595
596 if ((req->channels[0]->flags &
597 IEEE80211_CHAN_NO_IR) ||
598 !req->n_ssids) {
599 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
600 } else {
601 ieee80211_scan_state_send_probe(local, &next_delay);
602 next_delay = IEEE80211_CHANNEL_TIME;
603 }
604
605 /* Now, just wait a bit and we are all done! */
606 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
607 next_delay);
608 return 0;
609 } else {
610 /* Do normal software scan */
611 __set_bit(SCAN_SW_SCANNING, &local->scanning);
612 }
613
614 ieee80211_recalc_idle(local);
615
616 if (local->ops->hw_scan) {
617 WARN_ON(!ieee80211_prep_hw_scan(local));
618 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
619 } else {
620 rc = ieee80211_start_sw_scan(local, sdata);
621 }
622
623 if (rc) {
624 kfree(local->hw_scan_req);
625 local->hw_scan_req = NULL;
626 local->scanning = 0;
627
628 ieee80211_recalc_idle(local);
629
630 local->scan_req = NULL;
631 RCU_INIT_POINTER(local->scan_sdata, NULL);
632 }
633
634 return rc;
635 }
636
637 static unsigned long
638 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
639 {
640 /*
641 * TODO: channel switching also consumes quite some time,
642 * add that delay as well to get a better estimation
643 */
644 if (chan->flags & IEEE80211_CHAN_NO_IR)
645 return IEEE80211_PASSIVE_CHANNEL_TIME;
646 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
647 }
648
649 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
650 unsigned long *next_delay)
651 {
652 bool associated = false;
653 bool tx_empty = true;
654 bool bad_latency;
655 struct ieee80211_sub_if_data *sdata;
656 struct ieee80211_channel *next_chan;
657 enum mac80211_scan_state next_scan_state;
658 struct cfg80211_scan_request *scan_req;
659
660 /*
661 * check if at least one STA interface is associated,
662 * check if at least one STA interface has pending tx frames
663 * and grab the lowest used beacon interval
664 */
665 mutex_lock(&local->iflist_mtx);
666 list_for_each_entry(sdata, &local->interfaces, list) {
667 if (!ieee80211_sdata_running(sdata))
668 continue;
669
670 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
671 if (sdata->u.mgd.associated) {
672 associated = true;
673
674 if (!qdisc_all_tx_empty(sdata->dev)) {
675 tx_empty = false;
676 break;
677 }
678 }
679 }
680 }
681 mutex_unlock(&local->iflist_mtx);
682
683 scan_req = rcu_dereference_protected(local->scan_req,
684 lockdep_is_held(&local->mtx));
685
686 next_chan = scan_req->channels[local->scan_channel_idx];
687
688 /*
689 * we're currently scanning a different channel, let's
690 * see if we can scan another channel without interfering
691 * with the current traffic situation.
692 *
693 * Keep good latency, do not stay off-channel more than 125 ms.
694 */
695
696 bad_latency = time_after(jiffies +
697 ieee80211_scan_get_channel_time(next_chan),
698 local->leave_oper_channel_time + HZ / 8);
699
700 if (associated && !tx_empty) {
701 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
702 next_scan_state = SCAN_ABORT;
703 else
704 next_scan_state = SCAN_SUSPEND;
705 } else if (associated && bad_latency) {
706 next_scan_state = SCAN_SUSPEND;
707 } else {
708 next_scan_state = SCAN_SET_CHANNEL;
709 }
710
711 local->next_scan_state = next_scan_state;
712
713 *next_delay = 0;
714 }
715
716 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
717 unsigned long *next_delay)
718 {
719 int skip;
720 struct ieee80211_channel *chan;
721 enum nl80211_bss_scan_width oper_scan_width;
722 struct cfg80211_scan_request *scan_req;
723
724 scan_req = rcu_dereference_protected(local->scan_req,
725 lockdep_is_held(&local->mtx));
726
727 skip = 0;
728 chan = scan_req->channels[local->scan_channel_idx];
729
730 local->scan_chandef.chan = chan;
731 local->scan_chandef.center_freq1 = chan->center_freq;
732 local->scan_chandef.center_freq2 = 0;
733 switch (scan_req->scan_width) {
734 case NL80211_BSS_CHAN_WIDTH_5:
735 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
736 break;
737 case NL80211_BSS_CHAN_WIDTH_10:
738 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
739 break;
740 case NL80211_BSS_CHAN_WIDTH_20:
741 /* If scanning on oper channel, use whatever channel-type
742 * is currently in use.
743 */
744 oper_scan_width = cfg80211_chandef_to_scan_width(
745 &local->_oper_chandef);
746 if (chan == local->_oper_chandef.chan &&
747 oper_scan_width == scan_req->scan_width)
748 local->scan_chandef = local->_oper_chandef;
749 else
750 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
751 break;
752 }
753
754 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
755 skip = 1;
756
757 /* advance state machine to next channel/band */
758 local->scan_channel_idx++;
759
760 if (skip) {
761 /* if we skip this channel return to the decision state */
762 local->next_scan_state = SCAN_DECISION;
763 return;
764 }
765
766 /*
767 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
768 * (which unfortunately doesn't say _why_ step a) is done,
769 * but it waits for the probe delay or until a frame is
770 * received - and the received frame would update the NAV).
771 * For now, we do not support waiting until a frame is
772 * received.
773 *
774 * In any case, it is not necessary for a passive scan.
775 */
776 if (chan->flags & IEEE80211_CHAN_NO_IR || !scan_req->n_ssids) {
777 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
778 local->next_scan_state = SCAN_DECISION;
779 return;
780 }
781
782 /* active scan, send probes */
783 *next_delay = IEEE80211_PROBE_DELAY;
784 local->next_scan_state = SCAN_SEND_PROBE;
785 }
786
787 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
788 unsigned long *next_delay)
789 {
790 /* switch back to the operating channel */
791 local->scan_chandef.chan = NULL;
792 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
793
794 /* disable PS */
795 ieee80211_offchannel_return(local);
796
797 *next_delay = HZ / 5;
798 /* afterwards, resume scan & go to next channel */
799 local->next_scan_state = SCAN_RESUME;
800 }
801
802 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
803 unsigned long *next_delay)
804 {
805 ieee80211_offchannel_stop_vifs(local);
806
807 if (local->ops->flush) {
808 ieee80211_flush_queues(local, NULL, false);
809 *next_delay = 0;
810 } else
811 *next_delay = HZ / 10;
812
813 /* remember when we left the operating channel */
814 local->leave_oper_channel_time = jiffies;
815
816 /* advance to the next channel to be scanned */
817 local->next_scan_state = SCAN_SET_CHANNEL;
818 }
819
820 void ieee80211_scan_work(struct work_struct *work)
821 {
822 struct ieee80211_local *local =
823 container_of(work, struct ieee80211_local, scan_work.work);
824 struct ieee80211_sub_if_data *sdata;
825 struct cfg80211_scan_request *scan_req;
826 unsigned long next_delay = 0;
827 bool aborted;
828
829 mutex_lock(&local->mtx);
830
831 if (!ieee80211_can_run_worker(local)) {
832 aborted = true;
833 goto out_complete;
834 }
835
836 sdata = rcu_dereference_protected(local->scan_sdata,
837 lockdep_is_held(&local->mtx));
838 scan_req = rcu_dereference_protected(local->scan_req,
839 lockdep_is_held(&local->mtx));
840
841 /* When scanning on-channel, the first-callback means completed. */
842 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
843 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
844 goto out_complete;
845 }
846
847 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
848 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
849 goto out_complete;
850 }
851
852 if (!sdata || !scan_req)
853 goto out;
854
855 if (!local->scanning) {
856 int rc;
857
858 RCU_INIT_POINTER(local->scan_req, NULL);
859 RCU_INIT_POINTER(local->scan_sdata, NULL);
860
861 rc = __ieee80211_start_scan(sdata, scan_req);
862 if (rc) {
863 /* need to complete scan in cfg80211 */
864 rcu_assign_pointer(local->scan_req, scan_req);
865 aborted = true;
866 goto out_complete;
867 } else
868 goto out;
869 }
870
871 /*
872 * as long as no delay is required advance immediately
873 * without scheduling a new work
874 */
875 do {
876 if (!ieee80211_sdata_running(sdata)) {
877 aborted = true;
878 goto out_complete;
879 }
880
881 switch (local->next_scan_state) {
882 case SCAN_DECISION:
883 /* if no more bands/channels left, complete scan */
884 if (local->scan_channel_idx >= scan_req->n_channels) {
885 aborted = false;
886 goto out_complete;
887 }
888 ieee80211_scan_state_decision(local, &next_delay);
889 break;
890 case SCAN_SET_CHANNEL:
891 ieee80211_scan_state_set_channel(local, &next_delay);
892 break;
893 case SCAN_SEND_PROBE:
894 ieee80211_scan_state_send_probe(local, &next_delay);
895 break;
896 case SCAN_SUSPEND:
897 ieee80211_scan_state_suspend(local, &next_delay);
898 break;
899 case SCAN_RESUME:
900 ieee80211_scan_state_resume(local, &next_delay);
901 break;
902 case SCAN_ABORT:
903 aborted = true;
904 goto out_complete;
905 }
906 } while (next_delay == 0);
907
908 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
909 goto out;
910
911 out_complete:
912 __ieee80211_scan_completed(&local->hw, aborted);
913 out:
914 mutex_unlock(&local->mtx);
915 }
916
917 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
918 struct cfg80211_scan_request *req)
919 {
920 int res;
921
922 mutex_lock(&sdata->local->mtx);
923 res = __ieee80211_start_scan(sdata, req);
924 mutex_unlock(&sdata->local->mtx);
925
926 return res;
927 }
928
929 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
930 const u8 *ssid, u8 ssid_len,
931 struct ieee80211_channel *chan,
932 enum nl80211_bss_scan_width scan_width)
933 {
934 struct ieee80211_local *local = sdata->local;
935 int ret = -EBUSY;
936 enum ieee80211_band band;
937
938 mutex_lock(&local->mtx);
939
940 /* busy scanning */
941 if (local->scan_req)
942 goto unlock;
943
944 /* fill internal scan request */
945 if (!chan) {
946 int i, max_n;
947 int n_ch = 0;
948
949 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
950 if (!local->hw.wiphy->bands[band])
951 continue;
952
953 max_n = local->hw.wiphy->bands[band]->n_channels;
954 for (i = 0; i < max_n; i++) {
955 struct ieee80211_channel *tmp_ch =
956 &local->hw.wiphy->bands[band]->channels[i];
957
958 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
959 IEEE80211_CHAN_DISABLED))
960 continue;
961
962 local->int_scan_req->channels[n_ch] = tmp_ch;
963 n_ch++;
964 }
965 }
966
967 if (WARN_ON_ONCE(n_ch == 0))
968 goto unlock;
969
970 local->int_scan_req->n_channels = n_ch;
971 } else {
972 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR |
973 IEEE80211_CHAN_DISABLED)))
974 goto unlock;
975
976 local->int_scan_req->channels[0] = chan;
977 local->int_scan_req->n_channels = 1;
978 }
979
980 local->int_scan_req->ssids = &local->scan_ssid;
981 local->int_scan_req->n_ssids = 1;
982 local->int_scan_req->scan_width = scan_width;
983 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
984 local->int_scan_req->ssids[0].ssid_len = ssid_len;
985
986 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
987 unlock:
988 mutex_unlock(&local->mtx);
989 return ret;
990 }
991
992 /*
993 * Only call this function when a scan can't be queued -- under RTNL.
994 */
995 void ieee80211_scan_cancel(struct ieee80211_local *local)
996 {
997 /*
998 * We are canceling software scan, or deferred scan that was not
999 * yet really started (see __ieee80211_start_scan ).
1000 *
1001 * Regarding hardware scan:
1002 * - we can not call __ieee80211_scan_completed() as when
1003 * SCAN_HW_SCANNING bit is set this function change
1004 * local->hw_scan_req to operate on 5G band, what race with
1005 * driver which can use local->hw_scan_req
1006 *
1007 * - we can not cancel scan_work since driver can schedule it
1008 * by ieee80211_scan_completed(..., true) to finish scan
1009 *
1010 * Hence we only call the cancel_hw_scan() callback, but the low-level
1011 * driver is still responsible for calling ieee80211_scan_completed()
1012 * after the scan was completed/aborted.
1013 */
1014
1015 mutex_lock(&local->mtx);
1016 if (!local->scan_req)
1017 goto out;
1018
1019 /*
1020 * We have a scan running and the driver already reported completion,
1021 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1022 * cancelled.
1023 */
1024 if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1025 test_bit(SCAN_COMPLETED, &local->scanning)) {
1026 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1027 goto out;
1028 }
1029
1030 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1031 /*
1032 * Make sure that __ieee80211_scan_completed doesn't trigger a
1033 * scan on another band.
1034 */
1035 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1036 if (local->ops->cancel_hw_scan)
1037 drv_cancel_hw_scan(local,
1038 rcu_dereference_protected(local->scan_sdata,
1039 lockdep_is_held(&local->mtx)));
1040 goto out;
1041 }
1042
1043 /*
1044 * If the work is currently running, it must be blocked on
1045 * the mutex, but we'll set scan_sdata = NULL and it'll
1046 * simply exit once it acquires the mutex.
1047 */
1048 cancel_delayed_work(&local->scan_work);
1049 /* and clean up */
1050 __ieee80211_scan_completed(&local->hw, true);
1051 out:
1052 mutex_unlock(&local->mtx);
1053 }
1054
1055 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1056 struct cfg80211_sched_scan_request *req)
1057 {
1058 struct ieee80211_local *local = sdata->local;
1059 struct ieee80211_scan_ies sched_scan_ies = {};
1060 struct cfg80211_chan_def chandef;
1061 int ret, i, iebufsz, num_bands = 0;
1062 u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1063 u8 bands_used = 0;
1064 u8 *ie;
1065 size_t len;
1066
1067 iebufsz = local->scan_ies_len + req->ie_len;
1068
1069 lockdep_assert_held(&local->mtx);
1070
1071 if (!local->ops->sched_scan_start)
1072 return -ENOTSUPP;
1073
1074 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1075 if (local->hw.wiphy->bands[i]) {
1076 bands_used |= BIT(i);
1077 rate_masks[i] = (u32) -1;
1078 num_bands++;
1079 }
1080 }
1081
1082 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1083 if (!ie) {
1084 ret = -ENOMEM;
1085 goto out;
1086 }
1087
1088 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1089
1090 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1091 &sched_scan_ies, req->ie,
1092 req->ie_len, bands_used,
1093 rate_masks, &chandef);
1094
1095 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1096 if (ret == 0) {
1097 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1098 rcu_assign_pointer(local->sched_scan_req, req);
1099 }
1100
1101 kfree(ie);
1102
1103 out:
1104 if (ret) {
1105 /* Clean in case of failure after HW restart or upon resume. */
1106 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1107 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1108 }
1109
1110 return ret;
1111 }
1112
1113 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1114 struct cfg80211_sched_scan_request *req)
1115 {
1116 struct ieee80211_local *local = sdata->local;
1117 int ret;
1118
1119 mutex_lock(&local->mtx);
1120
1121 if (rcu_access_pointer(local->sched_scan_sdata)) {
1122 mutex_unlock(&local->mtx);
1123 return -EBUSY;
1124 }
1125
1126 ret = __ieee80211_request_sched_scan_start(sdata, req);
1127
1128 mutex_unlock(&local->mtx);
1129 return ret;
1130 }
1131
1132 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1133 {
1134 struct ieee80211_local *local = sdata->local;
1135 int ret = 0;
1136
1137 mutex_lock(&local->mtx);
1138
1139 if (!local->ops->sched_scan_stop) {
1140 ret = -ENOTSUPP;
1141 goto out;
1142 }
1143
1144 /* We don't want to restart sched scan anymore. */
1145 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1146
1147 if (rcu_access_pointer(local->sched_scan_sdata)) {
1148 ret = drv_sched_scan_stop(local, sdata);
1149 if (!ret)
1150 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1151 }
1152 out:
1153 mutex_unlock(&local->mtx);
1154
1155 return ret;
1156 }
1157
1158 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1159 {
1160 struct ieee80211_local *local = hw_to_local(hw);
1161
1162 trace_api_sched_scan_results(local);
1163
1164 cfg80211_sched_scan_results(hw->wiphy);
1165 }
1166 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1167
1168 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1169 {
1170 mutex_lock(&local->mtx);
1171
1172 if (!rcu_access_pointer(local->sched_scan_sdata)) {
1173 mutex_unlock(&local->mtx);
1174 return;
1175 }
1176
1177 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1178
1179 /* If sched scan was aborted by the driver. */
1180 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1181
1182 mutex_unlock(&local->mtx);
1183
1184 cfg80211_sched_scan_stopped(local->hw.wiphy);
1185 }
1186
1187 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1188 {
1189 struct ieee80211_local *local =
1190 container_of(work, struct ieee80211_local,
1191 sched_scan_stopped_work);
1192
1193 ieee80211_sched_scan_end(local);
1194 }
1195
1196 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1197 {
1198 struct ieee80211_local *local = hw_to_local(hw);
1199
1200 trace_api_sched_scan_stopped(local);
1201
1202 schedule_work(&local->sched_scan_stopped_work);
1203 }
1204 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
Linux kernel - Deliverables
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