1 /*
2 * Scanning implementation
3 *
4 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
5 * Copyright 2004, Instant802 Networks, Inc.
6 * Copyright 2005, Devicescape Software, Inc.
7 * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
8 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14
15 #include <linux/if_arp.h>
16 #include <linux/rtnetlink.h>
17 #include <linux/pm_qos_params.h>
18 #include <net/sch_generic.h>
19 #include <linux/slab.h>
20 #include <net/mac80211.h>
21
22 #include "ieee80211_i.h"
23 #include "driver-ops.h"
24 #include "mesh.h"
25
26 #define IEEE80211_PROBE_DELAY (HZ / 33)
27 #define IEEE80211_CHANNEL_TIME (HZ / 33)
28 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
29
30 struct ieee80211_bss *
ieee80211_rx_bss_get(struct ieee80211_local * local,u8 * bssid,int freq,u8 * ssid,u8 ssid_len)31 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
32 u8 *ssid, u8 ssid_len)
33 {
34 struct cfg80211_bss *cbss;
35
36 cbss = cfg80211_get_bss(local->hw.wiphy,
37 ieee80211_get_channel(local->hw.wiphy, freq),
38 bssid, ssid, ssid_len, 0, 0);
39 if (!cbss)
40 return NULL;
41 return (void *)cbss->priv;
42 }
43
ieee80211_rx_bss_free(struct cfg80211_bss * cbss)44 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
45 {
46 struct ieee80211_bss *bss = (void *)cbss->priv;
47
48 kfree(bss_mesh_id(bss));
49 kfree(bss_mesh_cfg(bss));
50 }
51
ieee80211_rx_bss_put(struct ieee80211_local * local,struct ieee80211_bss * bss)52 void ieee80211_rx_bss_put(struct ieee80211_local *local,
53 struct ieee80211_bss *bss)
54 {
55 if (!bss)
56 return;
57 cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
58 }
59
is_uapsd_supported(struct ieee802_11_elems * elems)60 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
61 {
62 u8 qos_info;
63
64 if (elems->wmm_info && elems->wmm_info_len == 7
65 && elems->wmm_info[5] == 1)
66 qos_info = elems->wmm_info[6];
67 else if (elems->wmm_param && elems->wmm_param_len == 24
68 && elems->wmm_param[5] == 1)
69 qos_info = elems->wmm_param[6];
70 else
71 /* no valid wmm information or parameter element found */
72 return false;
73
74 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
75 }
76
77 struct ieee80211_bss *
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)78 ieee80211_bss_info_update(struct ieee80211_local *local,
79 struct ieee80211_rx_status *rx_status,
80 struct ieee80211_mgmt *mgmt,
81 size_t len,
82 struct ieee802_11_elems *elems,
83 struct ieee80211_channel *channel,
84 bool beacon)
85 {
86 struct cfg80211_bss *cbss;
87 struct ieee80211_bss *bss;
88 int clen, srlen;
89 s32 signal = 0;
90
91 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
92 signal = rx_status->signal * 100;
93 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
94 signal = (rx_status->signal * 100) / local->hw.max_signal;
95
96 cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
97 mgmt, len, signal, GFP_ATOMIC);
98
99 if (!cbss)
100 return NULL;
101
102 cbss->free_priv = ieee80211_rx_bss_free;
103 bss = (void *)cbss->priv;
104
105 /* save the ERP value so that it is available at association time */
106 if (elems->erp_info && elems->erp_info_len >= 1) {
107 bss->erp_value = elems->erp_info[0];
108 bss->has_erp_value = 1;
109 }
110
111 if (elems->tim) {
112 struct ieee80211_tim_ie *tim_ie =
113 (struct ieee80211_tim_ie *)elems->tim;
114 bss->dtim_period = tim_ie->dtim_period;
115 }
116
117 /* If the beacon had no TIM IE, or it was invalid, use 1 */
118 if (beacon && !bss->dtim_period)
119 bss->dtim_period = 1;
120
121 /* replace old supported rates if we get new values */
122 srlen = 0;
123 if (elems->supp_rates) {
124 clen = IEEE80211_MAX_SUPP_RATES;
125 if (clen > elems->supp_rates_len)
126 clen = elems->supp_rates_len;
127 memcpy(bss->supp_rates, elems->supp_rates, clen);
128 srlen += clen;
129 }
130 if (elems->ext_supp_rates) {
131 clen = IEEE80211_MAX_SUPP_RATES - srlen;
132 if (clen > elems->ext_supp_rates_len)
133 clen = elems->ext_supp_rates_len;
134 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
135 srlen += clen;
136 }
137 if (srlen)
138 bss->supp_rates_len = srlen;
139
140 bss->wmm_used = elems->wmm_param || elems->wmm_info;
141 bss->uapsd_supported = is_uapsd_supported(elems);
142
143 if (!beacon)
144 bss->last_probe_resp = jiffies;
145
146 return bss;
147 }
148
149 ieee80211_rx_result
ieee80211_scan_rx(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)150 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
151 {
152 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
153 struct ieee80211_mgmt *mgmt;
154 struct ieee80211_bss *bss;
155 u8 *elements;
156 struct ieee80211_channel *channel;
157 size_t baselen;
158 int freq;
159 __le16 fc;
160 bool presp, beacon = false;
161 struct ieee802_11_elems elems;
162
163 if (skb->len < 2)
164 return RX_DROP_UNUSABLE;
165
166 mgmt = (struct ieee80211_mgmt *) skb->data;
167 fc = mgmt->frame_control;
168
169 if (ieee80211_is_ctl(fc))
170 return RX_CONTINUE;
171
172 if (skb->len < 24)
173 return RX_DROP_MONITOR;
174
175 presp = ieee80211_is_probe_resp(fc);
176 if (presp) {
177 /* ignore ProbeResp to foreign address */
178 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
179 return RX_DROP_MONITOR;
180
181 presp = true;
182 elements = mgmt->u.probe_resp.variable;
183 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
184 } else {
185 beacon = ieee80211_is_beacon(fc);
186 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
187 elements = mgmt->u.beacon.variable;
188 }
189
190 if (!presp && !beacon)
191 return RX_CONTINUE;
192
193 if (baselen > skb->len)
194 return RX_DROP_MONITOR;
195
196 ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
197
198 if (elems.ds_params && elems.ds_params_len == 1)
199 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
200 rx_status->band);
201 else
202 freq = rx_status->freq;
203
204 channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
205
206 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
207 return RX_DROP_MONITOR;
208
209 bss = ieee80211_bss_info_update(sdata->local, rx_status,
210 mgmt, skb->len, &elems,
211 channel, beacon);
212 if (bss)
213 ieee80211_rx_bss_put(sdata->local, bss);
214
215 /* If we are on-operating-channel, and this packet is for the
216 * current channel, pass the pkt on up the stack so that
217 * the rest of the stack can make use of it.
218 */
219 if (ieee80211_cfg_on_oper_channel(sdata->local)
220 && (channel == sdata->local->oper_channel))
221 return RX_CONTINUE;
222
223 dev_kfree_skb(skb);
224 return RX_QUEUED;
225 }
226
227 /* return false if no more work */
ieee80211_prep_hw_scan(struct ieee80211_local * local)228 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
229 {
230 struct cfg80211_scan_request *req = local->scan_req;
231 enum ieee80211_band band;
232 int i, ielen, n_chans;
233
234 do {
235 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
236 return false;
237
238 band = local->hw_scan_band;
239 n_chans = 0;
240 for (i = 0; i < req->n_channels; i++) {
241 if (req->channels[i]->band == band) {
242 local->hw_scan_req->channels[n_chans] =
243 req->channels[i];
244 n_chans++;
245 }
246 }
247
248 local->hw_scan_band++;
249 } while (!n_chans);
250
251 local->hw_scan_req->n_channels = n_chans;
252
253 ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
254 req->ie, req->ie_len, band, (u32) -1,
255 0);
256 local->hw_scan_req->ie_len = ielen;
257
258 return true;
259 }
260
__ieee80211_scan_completed(struct ieee80211_hw * hw,bool aborted,bool was_hw_scan)261 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
262 bool was_hw_scan)
263 {
264 struct ieee80211_local *local = hw_to_local(hw);
265 bool on_oper_chan;
266 bool enable_beacons = false;
267
268 lockdep_assert_held(&local->mtx);
269
270 /*
271 * It's ok to abort a not-yet-running scan (that
272 * we have one at all will be verified by checking
273 * local->scan_req next), but not to complete it
274 * successfully.
275 */
276 if (WARN_ON(!local->scanning && !aborted))
277 aborted = true;
278
279 if (WARN_ON(!local->scan_req))
280 return;
281
282 if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
283 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
284 if (rc == 0)
285 return;
286 }
287
288 kfree(local->hw_scan_req);
289 local->hw_scan_req = NULL;
290
291 if (local->scan_req != local->int_scan_req)
292 cfg80211_scan_done(local->scan_req, aborted);
293 local->scan_req = NULL;
294 local->scan_sdata = NULL;
295
296 local->scanning = 0;
297 local->scan_channel = NULL;
298
299 on_oper_chan = ieee80211_cfg_on_oper_channel(local);
300
301 if (was_hw_scan || !on_oper_chan)
302 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
303 else
304 /* Set power back to normal operating levels. */
305 ieee80211_hw_config(local, 0);
306
307 if (!was_hw_scan) {
308 bool on_oper_chan2;
309 ieee80211_configure_filter(local);
310 drv_sw_scan_complete(local);
311 on_oper_chan2 = ieee80211_cfg_on_oper_channel(local);
312 /* We should always be on-channel at this point. */
313 WARN_ON(!on_oper_chan2);
314 if (on_oper_chan2 && (on_oper_chan != on_oper_chan2))
315 enable_beacons = true;
316
317 ieee80211_offchannel_return(local, enable_beacons, true);
318 }
319
320 ieee80211_recalc_idle(local);
321
322 ieee80211_mlme_notify_scan_completed(local);
323 ieee80211_ibss_notify_scan_completed(local);
324 ieee80211_mesh_notify_scan_completed(local);
325 ieee80211_queue_work(&local->hw, &local->work_work);
326 }
327
ieee80211_scan_completed(struct ieee80211_hw * hw,bool aborted)328 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
329 {
330 struct ieee80211_local *local = hw_to_local(hw);
331
332 trace_api_scan_completed(local, aborted);
333
334 set_bit(SCAN_COMPLETED, &local->scanning);
335 if (aborted)
336 set_bit(SCAN_ABORTED, &local->scanning);
337 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
338 }
339 EXPORT_SYMBOL(ieee80211_scan_completed);
340
ieee80211_start_sw_scan(struct ieee80211_local * local)341 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
342 {
343 /*
344 * Hardware/driver doesn't support hw_scan, so use software
345 * scanning instead. First send a nullfunc frame with power save
346 * bit on so that AP will buffer the frames for us while we are not
347 * listening, then send probe requests to each channel and wait for
348 * the responses. After all channels are scanned, tune back to the
349 * original channel and send a nullfunc frame with power save bit
350 * off to trigger the AP to send us all the buffered frames.
351 *
352 * Note that while local->sw_scanning is true everything else but
353 * nullfunc frames and probe requests will be dropped in
354 * ieee80211_tx_h_check_assoc().
355 */
356 drv_sw_scan_start(local);
357
358 local->leave_oper_channel_time = 0;
359 local->next_scan_state = SCAN_DECISION;
360 local->scan_channel_idx = 0;
361
362 /* We always want to use off-channel PS, even if we
363 * are not really leaving oper-channel. Don't
364 * tell the AP though, as long as we are on-channel.
365 */
366 ieee80211_offchannel_enable_all_ps(local, false);
367
368 ieee80211_configure_filter(local);
369
370 /* We need to set power level at maximum rate for scanning. */
371 ieee80211_hw_config(local, 0);
372
373 ieee80211_queue_delayed_work(&local->hw,
374 &local->scan_work,
375 IEEE80211_CHANNEL_TIME);
376
377 return 0;
378 }
379
380
__ieee80211_start_scan(struct ieee80211_sub_if_data * sdata,struct cfg80211_scan_request * req)381 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
382 struct cfg80211_scan_request *req)
383 {
384 struct ieee80211_local *local = sdata->local;
385 int rc;
386
387 lockdep_assert_held(&local->mtx);
388
389 if (local->scan_req)
390 return -EBUSY;
391
392 if (!list_empty(&local->work_list)) {
393 /* wait for the work to finish/time out */
394 local->scan_req = req;
395 local->scan_sdata = sdata;
396 return 0;
397 }
398
399 if (local->ops->hw_scan) {
400 u8 *ies;
401
402 local->hw_scan_req = kmalloc(
403 sizeof(*local->hw_scan_req) +
404 req->n_channels * sizeof(req->channels[0]) +
405 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
406 req->ie_len, GFP_KERNEL);
407 if (!local->hw_scan_req)
408 return -ENOMEM;
409
410 local->hw_scan_req->ssids = req->ssids;
411 local->hw_scan_req->n_ssids = req->n_ssids;
412 ies = (u8 *)local->hw_scan_req +
413 sizeof(*local->hw_scan_req) +
414 req->n_channels * sizeof(req->channels[0]);
415 local->hw_scan_req->ie = ies;
416
417 local->hw_scan_band = 0;
418
419 /*
420 * After allocating local->hw_scan_req, we must
421 * go through until ieee80211_prep_hw_scan(), so
422 * anything that might be changed here and leave
423 * this function early must not go after this
424 * allocation.
425 */
426 }
427
428 local->scan_req = req;
429 local->scan_sdata = sdata;
430
431 if (local->ops->hw_scan)
432 __set_bit(SCAN_HW_SCANNING, &local->scanning);
433 else
434 __set_bit(SCAN_SW_SCANNING, &local->scanning);
435
436 ieee80211_recalc_idle(local);
437
438 if (local->ops->hw_scan) {
439 WARN_ON(!ieee80211_prep_hw_scan(local));
440 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
441 } else
442 rc = ieee80211_start_sw_scan(local);
443
444 if (rc) {
445 kfree(local->hw_scan_req);
446 local->hw_scan_req = NULL;
447 local->scanning = 0;
448
449 ieee80211_recalc_idle(local);
450
451 local->scan_req = NULL;
452 local->scan_sdata = NULL;
453 }
454
455 return rc;
456 }
457
458 static unsigned long
ieee80211_scan_get_channel_time(struct ieee80211_channel * chan)459 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
460 {
461 /*
462 * TODO: channel switching also consumes quite some time,
463 * add that delay as well to get a better estimation
464 */
465 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
466 return IEEE80211_PASSIVE_CHANNEL_TIME;
467 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
468 }
469
ieee80211_scan_state_decision(struct ieee80211_local * local,unsigned long * next_delay)470 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
471 unsigned long *next_delay)
472 {
473 bool associated = false;
474 bool tx_empty = true;
475 bool bad_latency;
476 bool listen_int_exceeded;
477 unsigned long min_beacon_int = 0;
478 struct ieee80211_sub_if_data *sdata;
479 struct ieee80211_channel *next_chan;
480
481 /*
482 * check if at least one STA interface is associated,
483 * check if at least one STA interface has pending tx frames
484 * and grab the lowest used beacon interval
485 */
486 mutex_lock(&local->iflist_mtx);
487 list_for_each_entry(sdata, &local->interfaces, list) {
488 if (!ieee80211_sdata_running(sdata))
489 continue;
490
491 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
492 if (sdata->u.mgd.associated) {
493 associated = true;
494
495 if (sdata->vif.bss_conf.beacon_int <
496 min_beacon_int || min_beacon_int == 0)
497 min_beacon_int =
498 sdata->vif.bss_conf.beacon_int;
499
500 if (!qdisc_all_tx_empty(sdata->dev)) {
501 tx_empty = false;
502 break;
503 }
504 }
505 }
506 }
507 mutex_unlock(&local->iflist_mtx);
508
509 next_chan = local->scan_req->channels[local->scan_channel_idx];
510
511 if (ieee80211_cfg_on_oper_channel(local)) {
512 /* We're currently on operating channel. */
513 if (next_chan == local->oper_channel)
514 /* We don't need to move off of operating channel. */
515 local->next_scan_state = SCAN_SET_CHANNEL;
516 else
517 /*
518 * We do need to leave operating channel, as next
519 * scan is somewhere else.
520 */
521 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
522 } else {
523 /*
524 * we're currently scanning a different channel, let's
525 * see if we can scan another channel without interfering
526 * with the current traffic situation.
527 *
528 * Since we don't know if the AP has pending frames for us
529 * we can only check for our tx queues and use the current
530 * pm_qos requirements for rx. Hence, if no tx traffic occurs
531 * at all we will scan as many channels in a row as the pm_qos
532 * latency allows us to. Additionally we also check for the
533 * currently negotiated listen interval to prevent losing
534 * frames unnecessarily.
535 *
536 * Otherwise switch back to the operating channel.
537 */
538
539 bad_latency = time_after(jiffies +
540 ieee80211_scan_get_channel_time(next_chan),
541 local->leave_oper_channel_time +
542 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
543
544 listen_int_exceeded = time_after(jiffies +
545 ieee80211_scan_get_channel_time(next_chan),
546 local->leave_oper_channel_time +
547 usecs_to_jiffies(min_beacon_int * 1024) *
548 local->hw.conf.listen_interval);
549
550 if (associated && ( !tx_empty || bad_latency ||
551 listen_int_exceeded))
552 local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
553 else
554 local->next_scan_state = SCAN_SET_CHANNEL;
555 }
556
557 *next_delay = 0;
558 }
559
ieee80211_scan_state_leave_oper_channel(struct ieee80211_local * local,unsigned long * next_delay)560 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
561 unsigned long *next_delay)
562 {
563 /* PS will already be in off-channel mode,
564 * we do that once at the beginning of scanning.
565 */
566 ieee80211_offchannel_stop_vifs(local, false);
567
568 /*
569 * What if the nullfunc frames didn't arrive?
570 */
571 drv_flush(local, false);
572 if (local->ops->flush)
573 *next_delay = 0;
574 else
575 *next_delay = HZ / 10;
576
577 /* remember when we left the operating channel */
578 local->leave_oper_channel_time = jiffies;
579
580 /* advance to the next channel to be scanned */
581 local->next_scan_state = SCAN_SET_CHANNEL;
582 }
583
ieee80211_scan_state_enter_oper_channel(struct ieee80211_local * local,unsigned long * next_delay)584 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
585 unsigned long *next_delay)
586 {
587 /* switch back to the operating channel */
588 local->scan_channel = NULL;
589 if (!ieee80211_cfg_on_oper_channel(local))
590 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
591
592 /*
593 * Re-enable vifs and beaconing. Leave PS
594 * in off-channel state..will put that back
595 * on-channel at the end of scanning.
596 */
597 ieee80211_offchannel_return(local, true, false);
598
599 *next_delay = HZ / 5;
600 local->next_scan_state = SCAN_DECISION;
601 }
602
ieee80211_scan_state_set_channel(struct ieee80211_local * local,unsigned long * next_delay)603 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
604 unsigned long *next_delay)
605 {
606 int skip;
607 struct ieee80211_channel *chan;
608
609 skip = 0;
610 chan = local->scan_req->channels[local->scan_channel_idx];
611
612 local->scan_channel = chan;
613
614 /* Only call hw-config if we really need to change channels. */
615 if (chan != local->hw.conf.channel)
616 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
617 skip = 1;
618
619 /* advance state machine to next channel/band */
620 local->scan_channel_idx++;
621
622 if (skip) {
623 /* if we skip this channel return to the decision state */
624 local->next_scan_state = SCAN_DECISION;
625 return;
626 }
627
628 /*
629 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
630 * (which unfortunately doesn't say _why_ step a) is done,
631 * but it waits for the probe delay or until a frame is
632 * received - and the received frame would update the NAV).
633 * For now, we do not support waiting until a frame is
634 * received.
635 *
636 * In any case, it is not necessary for a passive scan.
637 */
638 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
639 !local->scan_req->n_ssids) {
640 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
641 local->next_scan_state = SCAN_DECISION;
642 return;
643 }
644
645 /* active scan, send probes */
646 *next_delay = IEEE80211_PROBE_DELAY;
647 local->next_scan_state = SCAN_SEND_PROBE;
648 }
649
ieee80211_scan_state_send_probe(struct ieee80211_local * local,unsigned long * next_delay)650 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
651 unsigned long *next_delay)
652 {
653 int i;
654 struct ieee80211_sub_if_data *sdata = local->scan_sdata;
655
656 for (i = 0; i < local->scan_req->n_ssids; i++)
657 ieee80211_send_probe_req(
658 sdata, NULL,
659 local->scan_req->ssids[i].ssid,
660 local->scan_req->ssids[i].ssid_len,
661 local->scan_req->ie, local->scan_req->ie_len);
662
663 /*
664 * After sending probe requests, wait for probe responses
665 * on the channel.
666 */
667 *next_delay = IEEE80211_CHANNEL_TIME;
668 local->next_scan_state = SCAN_DECISION;
669 }
670
ieee80211_scan_work(struct work_struct * work)671 void ieee80211_scan_work(struct work_struct *work)
672 {
673 struct ieee80211_local *local =
674 container_of(work, struct ieee80211_local, scan_work.work);
675 struct ieee80211_sub_if_data *sdata;
676 unsigned long next_delay = 0;
677 bool aborted, hw_scan;
678
679 mutex_lock(&local->mtx);
680
681 sdata = local->scan_sdata;
682
683 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
684 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
685 goto out_complete;
686 }
687
688 if (!sdata || !local->scan_req)
689 goto out;
690
691 if (local->scan_req && !local->scanning) {
692 struct cfg80211_scan_request *req = local->scan_req;
693 int rc;
694
695 local->scan_req = NULL;
696 local->scan_sdata = NULL;
697
698 rc = __ieee80211_start_scan(sdata, req);
699 if (rc) {
700 /* need to complete scan in cfg80211 */
701 local->scan_req = req;
702 aborted = true;
703 goto out_complete;
704 } else
705 goto out;
706 }
707
708 /*
709 * Avoid re-scheduling when the sdata is going away.
710 */
711 if (!ieee80211_sdata_running(sdata)) {
712 aborted = true;
713 goto out_complete;
714 }
715
716 /*
717 * as long as no delay is required advance immediately
718 * without scheduling a new work
719 */
720 do {
721 switch (local->next_scan_state) {
722 case SCAN_DECISION:
723 /* if no more bands/channels left, complete scan */
724 if (local->scan_channel_idx >= local->scan_req->n_channels) {
725 aborted = false;
726 goto out_complete;
727 }
728 ieee80211_scan_state_decision(local, &next_delay);
729 break;
730 case SCAN_SET_CHANNEL:
731 ieee80211_scan_state_set_channel(local, &next_delay);
732 break;
733 case SCAN_SEND_PROBE:
734 ieee80211_scan_state_send_probe(local, &next_delay);
735 break;
736 case SCAN_LEAVE_OPER_CHANNEL:
737 ieee80211_scan_state_leave_oper_channel(local, &next_delay);
738 break;
739 case SCAN_ENTER_OPER_CHANNEL:
740 ieee80211_scan_state_enter_oper_channel(local, &next_delay);
741 break;
742 }
743 } while (next_delay == 0);
744
745 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
746 goto out;
747
748 out_complete:
749 hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
750 __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
751 out:
752 mutex_unlock(&local->mtx);
753 }
754
ieee80211_request_scan(struct ieee80211_sub_if_data * sdata,struct cfg80211_scan_request * req)755 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
756 struct cfg80211_scan_request *req)
757 {
758 int res;
759
760 mutex_lock(&sdata->local->mtx);
761 res = __ieee80211_start_scan(sdata, req);
762 mutex_unlock(&sdata->local->mtx);
763
764 return res;
765 }
766
ieee80211_request_internal_scan(struct ieee80211_sub_if_data * sdata,const u8 * ssid,u8 ssid_len,struct ieee80211_channel * chan)767 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
768 const u8 *ssid, u8 ssid_len,
769 struct ieee80211_channel *chan)
770 {
771 struct ieee80211_local *local = sdata->local;
772 int ret = -EBUSY;
773 enum ieee80211_band band;
774
775 mutex_lock(&local->mtx);
776
777 /* busy scanning */
778 if (local->scan_req)
779 goto unlock;
780
781 /* fill internal scan request */
782 if (!chan) {
783 int i, nchan = 0;
784
785 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
786 if (!local->hw.wiphy->bands[band])
787 continue;
788 for (i = 0;
789 i < local->hw.wiphy->bands[band]->n_channels;
790 i++) {
791 local->int_scan_req->channels[nchan] =
792 &local->hw.wiphy->bands[band]->channels[i];
793 nchan++;
794 }
795 }
796
797 local->int_scan_req->n_channels = nchan;
798 } else {
799 local->int_scan_req->channels[0] = chan;
800 local->int_scan_req->n_channels = 1;
801 }
802
803 local->int_scan_req->ssids = &local->scan_ssid;
804 local->int_scan_req->n_ssids = 1;
805 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
806 local->int_scan_req->ssids[0].ssid_len = ssid_len;
807
808 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
809 unlock:
810 mutex_unlock(&local->mtx);
811 return ret;
812 }
813
814 /*
815 * Only call this function when a scan can't be queued -- under RTNL.
816 */
ieee80211_scan_cancel(struct ieee80211_local * local)817 void ieee80211_scan_cancel(struct ieee80211_local *local)
818 {
819 bool abortscan;
820
821 /*
822 * We are only canceling software scan, or deferred scan that was not
823 * yet really started (see __ieee80211_start_scan ).
824 *
825 * Regarding hardware scan:
826 * - we can not call __ieee80211_scan_completed() as when
827 * SCAN_HW_SCANNING bit is set this function change
828 * local->hw_scan_req to operate on 5G band, what race with
829 * driver which can use local->hw_scan_req
830 *
831 * - we can not cancel scan_work since driver can schedule it
832 * by ieee80211_scan_completed(..., true) to finish scan
833 *
834 * Hence low lever driver is responsible for canceling HW scan.
835 */
836
837 mutex_lock(&local->mtx);
838 abortscan = local->scan_req && !test_bit(SCAN_HW_SCANNING, &local->scanning);
839 if (abortscan) {
840 /*
841 * The scan is canceled, but stop work from being pending.
842 *
843 * If the work is currently running, it must be blocked on
844 * the mutex, but we'll set scan_sdata = NULL and it'll
845 * simply exit once it acquires the mutex.
846 */
847 cancel_delayed_work(&local->scan_work);
848 /* and clean up */
849 __ieee80211_scan_completed(&local->hw, true, false);
850 }
851 mutex_unlock(&local->mtx);
852 }
853