scan.c revision 392b9ffb05b62fe38aa813b924d160ab663cec8d 
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/etherdevice.h>
17#include <linux/rtnetlink.h>
18#include <linux/pm_qos.h>
19#include <net/sch_generic.h>
20#include <linux/slab.h>
21#include <linux/export.h>
22#include <net/mac80211.h>
23
24#include "ieee80211_i.h"
25#include "driver-ops.h"
26#include "mesh.h"
27
28#define IEEE80211_PROBE_DELAY (HZ / 33)
29#define IEEE80211_CHANNEL_TIME (HZ / 33)
30#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
31
32void ieee80211_rx_bss_put(struct ieee80211_local *local,
33			  struct ieee80211_bss *bss)
34{
35	if (!bss)
36		return;
37	cfg80211_put_bss(local->hw.wiphy,
38			 container_of((void *)bss, struct cfg80211_bss, priv));
39}
40
41static bool is_uapsd_supported(struct ieee802_11_elems *elems)
42{
43	u8 qos_info;
44
45	if (elems->wmm_info && elems->wmm_info_len == 7
46	    && elems->wmm_info[5] == 1)
47		qos_info = elems->wmm_info[6];
48	else if (elems->wmm_param && elems->wmm_param_len == 24
49		 && elems->wmm_param[5] == 1)
50		qos_info = elems->wmm_param[6];
51	else
52		/* no valid wmm information or parameter element found */
53		return false;
54
55	return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
56}
57
58struct ieee80211_bss *
59ieee80211_bss_info_update(struct ieee80211_local *local,
60			  struct ieee80211_rx_status *rx_status,
61			  struct ieee80211_mgmt *mgmt, size_t len,
62			  struct ieee802_11_elems *elems,
63			  struct ieee80211_channel *channel)
64{
65	bool beacon = ieee80211_is_beacon(mgmt->frame_control);
66	struct cfg80211_bss *cbss;
67	struct ieee80211_bss *bss;
68	int clen, srlen;
69	enum nl80211_bss_scan_width scan_width;
70	s32 signal = 0;
71
72	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
73		signal = rx_status->signal * 100;
74	else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
75		signal = (rx_status->signal * 100) / local->hw.max_signal;
76
77	scan_width = NL80211_BSS_CHAN_WIDTH_20;
78	if (rx_status->flag & RX_FLAG_5MHZ)
79		scan_width = NL80211_BSS_CHAN_WIDTH_5;
80	if (rx_status->flag & RX_FLAG_10MHZ)
81		scan_width = NL80211_BSS_CHAN_WIDTH_10;
82
83	cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel,
84					       scan_width, mgmt, len, signal,
85					       GFP_ATOMIC);
86	if (!cbss)
87		return NULL;
88
89	bss = (void *)cbss->priv;
90
91	if (beacon)
92		bss->device_ts_beacon = rx_status->device_timestamp;
93	else
94		bss->device_ts_presp = rx_status->device_timestamp;
95
96	if (elems->parse_error) {
97		if (beacon)
98			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
99		else
100			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
101	} else {
102		if (beacon)
103			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
104		else
105			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
106	}
107
108	/* save the ERP value so that it is available at association time */
109	if (elems->erp_info && (!elems->parse_error ||
110				!(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
111		bss->erp_value = elems->erp_info[0];
112		bss->has_erp_value = true;
113		if (!elems->parse_error)
114			bss->valid_data |= IEEE80211_BSS_VALID_ERP;
115	}
116
117	/* replace old supported rates if we get new values */
118	if (!elems->parse_error ||
119	    !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
120		srlen = 0;
121		if (elems->supp_rates) {
122			clen = IEEE80211_MAX_SUPP_RATES;
123			if (clen > elems->supp_rates_len)
124				clen = elems->supp_rates_len;
125			memcpy(bss->supp_rates, elems->supp_rates, clen);
126			srlen += clen;
127		}
128		if (elems->ext_supp_rates) {
129			clen = IEEE80211_MAX_SUPP_RATES - srlen;
130			if (clen > elems->ext_supp_rates_len)
131				clen = elems->ext_supp_rates_len;
132			memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
133			       clen);
134			srlen += clen;
135		}
136		if (srlen) {
137			bss->supp_rates_len = srlen;
138			if (!elems->parse_error)
139				bss->valid_data |= IEEE80211_BSS_VALID_RATES;
140		}
141	}
142
143	if (!elems->parse_error ||
144	    !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
145		bss->wmm_used = elems->wmm_param || elems->wmm_info;
146		bss->uapsd_supported = is_uapsd_supported(elems);
147		if (!elems->parse_error)
148			bss->valid_data |= IEEE80211_BSS_VALID_WMM;
149	}
150
151	if (beacon) {
152		struct ieee80211_supported_band *sband =
153			local->hw.wiphy->bands[rx_status->band];
154		if (!(rx_status->flag & RX_FLAG_HT) &&
155		    !(rx_status->flag & RX_FLAG_VHT))
156			bss->beacon_rate =
157				&sband->bitrates[rx_status->rate_idx];
158	}
159
160	return bss;
161}
162
163void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
164{
165	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
166	struct ieee80211_sub_if_data *sdata1, *sdata2;
167	struct ieee80211_mgmt *mgmt = (void *)skb->data;
168	struct ieee80211_bss *bss;
169	u8 *elements;
170	struct ieee80211_channel *channel;
171	size_t baselen;
172	struct ieee802_11_elems elems;
173
174	if (skb->len < 24 ||
175	    (!ieee80211_is_probe_resp(mgmt->frame_control) &&
176	     !ieee80211_is_beacon(mgmt->frame_control)))
177		return;
178
179	sdata1 = rcu_dereference(local->scan_sdata);
180	sdata2 = rcu_dereference(local->sched_scan_sdata);
181
182	if (likely(!sdata1 && !sdata2))
183		return;
184
185	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
186		/* ignore ProbeResp to foreign address */
187		if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
188		    (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
189			return;
190
191		elements = mgmt->u.probe_resp.variable;
192		baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
193	} else {
194		baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
195		elements = mgmt->u.beacon.variable;
196	}
197
198	if (baselen > skb->len)
199		return;
200
201	ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
202
203	channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
204
205	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
206		return;
207
208	bss = ieee80211_bss_info_update(local, rx_status,
209					mgmt, skb->len, &elems,
210					channel);
211	if (bss)
212		ieee80211_rx_bss_put(local, bss);
213}
214
215static void
216ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
217			       enum nl80211_bss_scan_width scan_width)
218{
219	memset(chandef, 0, sizeof(*chandef));
220	switch (scan_width) {
221	case NL80211_BSS_CHAN_WIDTH_5:
222		chandef->width = NL80211_CHAN_WIDTH_5;
223		break;
224	case NL80211_BSS_CHAN_WIDTH_10:
225		chandef->width = NL80211_CHAN_WIDTH_10;
226		break;
227	default:
228		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
229		break;
230	}
231}
232
233/* return false if no more work */
234static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
235{
236	struct cfg80211_scan_request *req = local->scan_req;
237	struct cfg80211_chan_def chandef;
238	enum ieee80211_band band;
239	int i, ielen, n_chans;
240
241	do {
242		if (local->hw_scan_band == IEEE80211_NUM_BANDS)
243			return false;
244
245		band = local->hw_scan_band;
246		n_chans = 0;
247		for (i = 0; i < req->n_channels; i++) {
248			if (req->channels[i]->band == band) {
249				local->hw_scan_req->channels[n_chans] =
250							req->channels[i];
251				n_chans++;
252			}
253		}
254
255		local->hw_scan_band++;
256	} while (!n_chans);
257
258	local->hw_scan_req->n_channels = n_chans;
259	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
260
261	ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
262					 local->hw_scan_ies_bufsize,
263					 req->ie, req->ie_len, band,
264					 req->rates[band], &chandef);
265	local->hw_scan_req->ie_len = ielen;
266	local->hw_scan_req->no_cck = req->no_cck;
267
268	return true;
269}
270
271static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
272				       bool was_hw_scan)
273{
274	struct ieee80211_local *local = hw_to_local(hw);
275
276	lockdep_assert_held(&local->mtx);
277
278	/*
279	 * It's ok to abort a not-yet-running scan (that
280	 * we have one at all will be verified by checking
281	 * local->scan_req next), but not to complete it
282	 * successfully.
283	 */
284	if (WARN_ON(!local->scanning && !aborted))
285		aborted = true;
286
287	if (WARN_ON(!local->scan_req))
288		return;
289
290	if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
291		int rc;
292
293		rc = drv_hw_scan(local,
294			rcu_dereference_protected(local->scan_sdata,
295						  lockdep_is_held(&local->mtx)),
296			local->hw_scan_req);
297
298		if (rc == 0)
299			return;
300	}
301
302	kfree(local->hw_scan_req);
303	local->hw_scan_req = NULL;
304
305	if (local->scan_req != local->int_scan_req)
306		cfg80211_scan_done(local->scan_req, aborted);
307	local->scan_req = NULL;
308	rcu_assign_pointer(local->scan_sdata, NULL);
309
310	local->scanning = 0;
311	local->scan_chandef.chan = NULL;
312
313	/* Set power back to normal operating levels. */
314	ieee80211_hw_config(local, 0);
315
316	if (!was_hw_scan) {
317		ieee80211_configure_filter(local);
318		drv_sw_scan_complete(local);
319		ieee80211_offchannel_return(local);
320	}
321
322	ieee80211_recalc_idle(local);
323
324	ieee80211_mlme_notify_scan_completed(local);
325	ieee80211_ibss_notify_scan_completed(local);
326	ieee80211_mesh_notify_scan_completed(local);
327	ieee80211_start_next_roc(local);
328}
329
330void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
331{
332	struct ieee80211_local *local = hw_to_local(hw);
333
334	trace_api_scan_completed(local, aborted);
335
336	set_bit(SCAN_COMPLETED, &local->scanning);
337	if (aborted)
338		set_bit(SCAN_ABORTED, &local->scanning);
339	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
340}
341EXPORT_SYMBOL(ieee80211_scan_completed);
342
343static int ieee80211_start_sw_scan(struct ieee80211_local *local)
344{
345	/* Software scan is not supported in multi-channel cases */
346	if (local->use_chanctx)
347		return -EOPNOTSUPP;
348
349	/*
350	 * Hardware/driver doesn't support hw_scan, so use software
351	 * scanning instead. First send a nullfunc frame with power save
352	 * bit on so that AP will buffer the frames for us while we are not
353	 * listening, then send probe requests to each channel and wait for
354	 * the responses. After all channels are scanned, tune back to the
355	 * original channel and send a nullfunc frame with power save bit
356	 * off to trigger the AP to send us all the buffered frames.
357	 *
358	 * Note that while local->sw_scanning is true everything else but
359	 * nullfunc frames and probe requests will be dropped in
360	 * ieee80211_tx_h_check_assoc().
361	 */
362	drv_sw_scan_start(local);
363
364	local->leave_oper_channel_time = jiffies;
365	local->next_scan_state = SCAN_DECISION;
366	local->scan_channel_idx = 0;
367
368	ieee80211_offchannel_stop_vifs(local);
369
370	/* ensure nullfunc is transmitted before leaving operating channel */
371	ieee80211_flush_queues(local, NULL);
372
373	ieee80211_configure_filter(local);
374
375	/* We need to set power level at maximum rate for scanning. */
376	ieee80211_hw_config(local, 0);
377
378	ieee80211_queue_delayed_work(&local->hw,
379				     &local->scan_work, 0);
380
381	return 0;
382}
383
384static bool ieee80211_can_scan(struct ieee80211_local *local,
385			       struct ieee80211_sub_if_data *sdata)
386{
387	if (local->radar_detect_enabled)
388		return false;
389
390	if (!list_empty(&local->roc_list))
391		return false;
392
393	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
394	    sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
395		return false;
396
397	return true;
398}
399
400void ieee80211_run_deferred_scan(struct ieee80211_local *local)
401{
402	lockdep_assert_held(&local->mtx);
403
404	if (!local->scan_req || local->scanning)
405		return;
406
407	if (!ieee80211_can_scan(local,
408				rcu_dereference_protected(
409					local->scan_sdata,
410					lockdep_is_held(&local->mtx))))
411		return;
412
413	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
414				     round_jiffies_relative(0));
415}
416
417static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
418					    unsigned long *next_delay)
419{
420	int i;
421	struct ieee80211_sub_if_data *sdata;
422	enum ieee80211_band band = local->hw.conf.chandef.chan->band;
423	u32 tx_flags;
424
425	tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
426	if (local->scan_req->no_cck)
427		tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
428
429	sdata = rcu_dereference_protected(local->scan_sdata,
430					  lockdep_is_held(&local->mtx));
431
432	for (i = 0; i < local->scan_req->n_ssids; i++)
433		ieee80211_send_probe_req(
434			sdata, NULL,
435			local->scan_req->ssids[i].ssid,
436			local->scan_req->ssids[i].ssid_len,
437			local->scan_req->ie, local->scan_req->ie_len,
438			local->scan_req->rates[band], false,
439			tx_flags, local->hw.conf.chandef.chan, true);
440
441	/*
442	 * After sending probe requests, wait for probe responses
443	 * on the channel.
444	 */
445	*next_delay = IEEE80211_CHANNEL_TIME;
446	local->next_scan_state = SCAN_DECISION;
447}
448
449static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
450				  struct cfg80211_scan_request *req)
451{
452	struct ieee80211_local *local = sdata->local;
453	int rc;
454
455	lockdep_assert_held(&local->mtx);
456
457	if (local->scan_req)
458		return -EBUSY;
459
460	if (!ieee80211_can_scan(local, sdata)) {
461		/* wait for the work to finish/time out */
462		local->scan_req = req;
463		rcu_assign_pointer(local->scan_sdata, sdata);
464		return 0;
465	}
466
467	if (local->ops->hw_scan) {
468		u8 *ies;
469
470		local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
471					     local->scan_ies_len +
472					     req->ie_len;
473		local->hw_scan_req = kmalloc(
474				sizeof(*local->hw_scan_req) +
475				req->n_channels * sizeof(req->channels[0]) +
476				local->hw_scan_ies_bufsize, GFP_KERNEL);
477		if (!local->hw_scan_req)
478			return -ENOMEM;
479
480		local->hw_scan_req->ssids = req->ssids;
481		local->hw_scan_req->n_ssids = req->n_ssids;
482		ies = (u8 *)local->hw_scan_req +
483			sizeof(*local->hw_scan_req) +
484			req->n_channels * sizeof(req->channels[0]);
485		local->hw_scan_req->ie = ies;
486		local->hw_scan_req->flags = req->flags;
487
488		local->hw_scan_band = 0;
489
490		/*
491		 * After allocating local->hw_scan_req, we must
492		 * go through until ieee80211_prep_hw_scan(), so
493		 * anything that might be changed here and leave
494		 * this function early must not go after this
495		 * allocation.
496		 */
497	}
498
499	local->scan_req = req;
500	rcu_assign_pointer(local->scan_sdata, sdata);
501
502	if (local->ops->hw_scan) {
503		__set_bit(SCAN_HW_SCANNING, &local->scanning);
504	} else if ((req->n_channels == 1) &&
505		   (req->channels[0] == local->_oper_chandef.chan)) {
506		/*
507		 * If we are scanning only on the operating channel
508		 * then we do not need to stop normal activities
509		 */
510		unsigned long next_delay;
511
512		__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
513
514		ieee80211_recalc_idle(local);
515
516		/* Notify driver scan is starting, keep order of operations
517		 * same as normal software scan, in case that matters. */
518		drv_sw_scan_start(local);
519
520		ieee80211_configure_filter(local); /* accept probe-responses */
521
522		/* We need to ensure power level is at max for scanning. */
523		ieee80211_hw_config(local, 0);
524
525		if ((req->channels[0]->flags &
526		     IEEE80211_CHAN_PASSIVE_SCAN) ||
527		    !local->scan_req->n_ssids) {
528			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
529		} else {
530			ieee80211_scan_state_send_probe(local, &next_delay);
531			next_delay = IEEE80211_CHANNEL_TIME;
532		}
533
534		/* Now, just wait a bit and we are all done! */
535		ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
536					     next_delay);
537		return 0;
538	} else {
539		/* Do normal software scan */
540		__set_bit(SCAN_SW_SCANNING, &local->scanning);
541	}
542
543	ieee80211_recalc_idle(local);
544
545	if (local->ops->hw_scan) {
546		WARN_ON(!ieee80211_prep_hw_scan(local));
547		rc = drv_hw_scan(local, sdata, local->hw_scan_req);
548	} else
549		rc = ieee80211_start_sw_scan(local);
550
551	if (rc) {
552		kfree(local->hw_scan_req);
553		local->hw_scan_req = NULL;
554		local->scanning = 0;
555
556		ieee80211_recalc_idle(local);
557
558		local->scan_req = NULL;
559		rcu_assign_pointer(local->scan_sdata, NULL);
560	}
561
562	return rc;
563}
564
565static unsigned long
566ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
567{
568	/*
569	 * TODO: channel switching also consumes quite some time,
570	 * add that delay as well to get a better estimation
571	 */
572	if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
573		return IEEE80211_PASSIVE_CHANNEL_TIME;
574	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
575}
576
577static void ieee80211_scan_state_decision(struct ieee80211_local *local,
578					  unsigned long *next_delay)
579{
580	bool associated = false;
581	bool tx_empty = true;
582	bool bad_latency;
583	struct ieee80211_sub_if_data *sdata;
584	struct ieee80211_channel *next_chan;
585	enum mac80211_scan_state next_scan_state;
586
587	/*
588	 * check if at least one STA interface is associated,
589	 * check if at least one STA interface has pending tx frames
590	 * and grab the lowest used beacon interval
591	 */
592	mutex_lock(&local->iflist_mtx);
593	list_for_each_entry(sdata, &local->interfaces, list) {
594		if (!ieee80211_sdata_running(sdata))
595			continue;
596
597		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
598			if (sdata->u.mgd.associated) {
599				associated = true;
600
601				if (!qdisc_all_tx_empty(sdata->dev)) {
602					tx_empty = false;
603					break;
604				}
605			}
606		}
607	}
608	mutex_unlock(&local->iflist_mtx);
609
610	next_chan = local->scan_req->channels[local->scan_channel_idx];
611
612	/*
613	 * we're currently scanning a different channel, let's
614	 * see if we can scan another channel without interfering
615	 * with the current traffic situation.
616	 *
617	 * Keep good latency, do not stay off-channel more than 125 ms.
618	 */
619
620	bad_latency = time_after(jiffies +
621				 ieee80211_scan_get_channel_time(next_chan),
622				 local->leave_oper_channel_time + HZ / 8);
623
624	if (associated && !tx_empty) {
625		if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
626			next_scan_state = SCAN_ABORT;
627		else
628			next_scan_state = SCAN_SUSPEND;
629	} else if (associated && bad_latency) {
630		next_scan_state = SCAN_SUSPEND;
631	} else {
632		next_scan_state = SCAN_SET_CHANNEL;
633	}
634
635	local->next_scan_state = next_scan_state;
636
637	*next_delay = 0;
638}
639
640static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
641					     unsigned long *next_delay)
642{
643	int skip;
644	struct ieee80211_channel *chan;
645	enum nl80211_bss_scan_width oper_scan_width;
646
647	skip = 0;
648	chan = local->scan_req->channels[local->scan_channel_idx];
649
650	local->scan_chandef.chan = chan;
651	local->scan_chandef.center_freq1 = chan->center_freq;
652	local->scan_chandef.center_freq2 = 0;
653	switch (local->scan_req->scan_width) {
654	case NL80211_BSS_CHAN_WIDTH_5:
655		local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
656		break;
657	case NL80211_BSS_CHAN_WIDTH_10:
658		local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
659		break;
660	case NL80211_BSS_CHAN_WIDTH_20:
661		/* If scanning on oper channel, use whatever channel-type
662		 * is currently in use.
663		 */
664		oper_scan_width = cfg80211_chandef_to_scan_width(
665					&local->_oper_chandef);
666		if (chan == local->_oper_chandef.chan &&
667		    oper_scan_width == local->scan_req->scan_width)
668			local->scan_chandef = local->_oper_chandef;
669		else
670			local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
671		break;
672	}
673
674	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
675		skip = 1;
676
677	/* advance state machine to next channel/band */
678	local->scan_channel_idx++;
679
680	if (skip) {
681		/* if we skip this channel return to the decision state */
682		local->next_scan_state = SCAN_DECISION;
683		return;
684	}
685
686	/*
687	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
688	 * (which unfortunately doesn't say _why_ step a) is done,
689	 * but it waits for the probe delay or until a frame is
690	 * received - and the received frame would update the NAV).
691	 * For now, we do not support waiting until a frame is
692	 * received.
693	 *
694	 * In any case, it is not necessary for a passive scan.
695	 */
696	if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
697	    !local->scan_req->n_ssids) {
698		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
699		local->next_scan_state = SCAN_DECISION;
700		return;
701	}
702
703	/* active scan, send probes */
704	*next_delay = IEEE80211_PROBE_DELAY;
705	local->next_scan_state = SCAN_SEND_PROBE;
706}
707
708static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
709					 unsigned long *next_delay)
710{
711	/* switch back to the operating channel */
712	local->scan_chandef.chan = NULL;
713	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
714
715	/* disable PS */
716	ieee80211_offchannel_return(local);
717
718	*next_delay = HZ / 5;
719	/* afterwards, resume scan & go to next channel */
720	local->next_scan_state = SCAN_RESUME;
721}
722
723static void ieee80211_scan_state_resume(struct ieee80211_local *local,
724					unsigned long *next_delay)
725{
726	ieee80211_offchannel_stop_vifs(local);
727
728	if (local->ops->flush) {
729		ieee80211_flush_queues(local, NULL);
730		*next_delay = 0;
731	} else
732		*next_delay = HZ / 10;
733
734	/* remember when we left the operating channel */
735	local->leave_oper_channel_time = jiffies;
736
737	/* advance to the next channel to be scanned */
738	local->next_scan_state = SCAN_SET_CHANNEL;
739}
740
741void ieee80211_scan_work(struct work_struct *work)
742{
743	struct ieee80211_local *local =
744		container_of(work, struct ieee80211_local, scan_work.work);
745	struct ieee80211_sub_if_data *sdata;
746	unsigned long next_delay = 0;
747	bool aborted, hw_scan;
748
749	mutex_lock(&local->mtx);
750
751	sdata = rcu_dereference_protected(local->scan_sdata,
752					  lockdep_is_held(&local->mtx));
753
754	/* When scanning on-channel, the first-callback means completed. */
755	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
756		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
757		goto out_complete;
758	}
759
760	if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
761		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
762		goto out_complete;
763	}
764
765	if (!sdata || !local->scan_req)
766		goto out;
767
768	if (local->scan_req && !local->scanning) {
769		struct cfg80211_scan_request *req = local->scan_req;
770		int rc;
771
772		local->scan_req = NULL;
773		rcu_assign_pointer(local->scan_sdata, NULL);
774
775		rc = __ieee80211_start_scan(sdata, req);
776		if (rc) {
777			/* need to complete scan in cfg80211 */
778			local->scan_req = req;
779			aborted = true;
780			goto out_complete;
781		} else
782			goto out;
783	}
784
785	/*
786	 * Avoid re-scheduling when the sdata is going away.
787	 */
788	if (!ieee80211_sdata_running(sdata)) {
789		aborted = true;
790		goto out_complete;
791	}
792
793	/*
794	 * as long as no delay is required advance immediately
795	 * without scheduling a new work
796	 */
797	do {
798		if (!ieee80211_sdata_running(sdata)) {
799			aborted = true;
800			goto out_complete;
801		}
802
803		switch (local->next_scan_state) {
804		case SCAN_DECISION:
805			/* if no more bands/channels left, complete scan */
806			if (local->scan_channel_idx >= local->scan_req->n_channels) {
807				aborted = false;
808				goto out_complete;
809			}
810			ieee80211_scan_state_decision(local, &next_delay);
811			break;
812		case SCAN_SET_CHANNEL:
813			ieee80211_scan_state_set_channel(local, &next_delay);
814			break;
815		case SCAN_SEND_PROBE:
816			ieee80211_scan_state_send_probe(local, &next_delay);
817			break;
818		case SCAN_SUSPEND:
819			ieee80211_scan_state_suspend(local, &next_delay);
820			break;
821		case SCAN_RESUME:
822			ieee80211_scan_state_resume(local, &next_delay);
823			break;
824		case SCAN_ABORT:
825			aborted = true;
826			goto out_complete;
827		}
828	} while (next_delay == 0);
829
830	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
831	goto out;
832
833out_complete:
834	hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
835	__ieee80211_scan_completed(&local->hw, aborted, hw_scan);
836out:
837	mutex_unlock(&local->mtx);
838}
839
840int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
841			   struct cfg80211_scan_request *req)
842{
843	int res;
844
845	mutex_lock(&sdata->local->mtx);
846	res = __ieee80211_start_scan(sdata, req);
847	mutex_unlock(&sdata->local->mtx);
848
849	return res;
850}
851
852int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
853				const u8 *ssid, u8 ssid_len,
854				struct ieee80211_channel *chan,
855				enum nl80211_bss_scan_width scan_width)
856{
857	struct ieee80211_local *local = sdata->local;
858	int ret = -EBUSY;
859	enum ieee80211_band band;
860
861	mutex_lock(&local->mtx);
862
863	/* busy scanning */
864	if (local->scan_req)
865		goto unlock;
866
867	/* fill internal scan request */
868	if (!chan) {
869		int i, max_n;
870		int n_ch = 0;
871
872		for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
873			if (!local->hw.wiphy->bands[band])
874				continue;
875
876			max_n = local->hw.wiphy->bands[band]->n_channels;
877			for (i = 0; i < max_n; i++) {
878				struct ieee80211_channel *tmp_ch =
879				    &local->hw.wiphy->bands[band]->channels[i];
880
881				if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
882						     IEEE80211_CHAN_DISABLED))
883					continue;
884
885				local->int_scan_req->channels[n_ch] = tmp_ch;
886				n_ch++;
887			}
888		}
889
890		if (WARN_ON_ONCE(n_ch == 0))
891			goto unlock;
892
893		local->int_scan_req->n_channels = n_ch;
894	} else {
895		if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
896						IEEE80211_CHAN_DISABLED)))
897			goto unlock;
898
899		local->int_scan_req->channels[0] = chan;
900		local->int_scan_req->n_channels = 1;
901	}
902
903	local->int_scan_req->ssids = &local->scan_ssid;
904	local->int_scan_req->n_ssids = 1;
905	local->int_scan_req->scan_width = scan_width;
906	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
907	local->int_scan_req->ssids[0].ssid_len = ssid_len;
908
909	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
910 unlock:
911	mutex_unlock(&local->mtx);
912	return ret;
913}
914
915/*
916 * Only call this function when a scan can't be queued -- under RTNL.
917 */
918void ieee80211_scan_cancel(struct ieee80211_local *local)
919{
920	/*
921	 * We are canceling software scan, or deferred scan that was not
922	 * yet really started (see __ieee80211_start_scan ).
923	 *
924	 * Regarding hardware scan:
925	 * - we can not call  __ieee80211_scan_completed() as when
926	 *   SCAN_HW_SCANNING bit is set this function change
927	 *   local->hw_scan_req to operate on 5G band, what race with
928	 *   driver which can use local->hw_scan_req
929	 *
930	 * - we can not cancel scan_work since driver can schedule it
931	 *   by ieee80211_scan_completed(..., true) to finish scan
932	 *
933	 * Hence we only call the cancel_hw_scan() callback, but the low-level
934	 * driver is still responsible for calling ieee80211_scan_completed()
935	 * after the scan was completed/aborted.
936	 */
937
938	mutex_lock(&local->mtx);
939	if (!local->scan_req)
940		goto out;
941
942	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
943		if (local->ops->cancel_hw_scan)
944			drv_cancel_hw_scan(local,
945				rcu_dereference_protected(local->scan_sdata,
946						lockdep_is_held(&local->mtx)));
947		goto out;
948	}
949
950	/*
951	 * If the work is currently running, it must be blocked on
952	 * the mutex, but we'll set scan_sdata = NULL and it'll
953	 * simply exit once it acquires the mutex.
954	 */
955	cancel_delayed_work(&local->scan_work);
956	/* and clean up */
957	__ieee80211_scan_completed(&local->hw, true, false);
958out:
959	mutex_unlock(&local->mtx);
960}
961
962int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
963				       struct cfg80211_sched_scan_request *req)
964{
965	struct ieee80211_local *local = sdata->local;
966	struct ieee80211_sched_scan_ies sched_scan_ies = {};
967	struct cfg80211_chan_def chandef;
968	int ret, i, iebufsz;
969
970	iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
971		  local->scan_ies_len + req->ie_len;
972
973	mutex_lock(&local->mtx);
974
975	if (rcu_access_pointer(local->sched_scan_sdata)) {
976		ret = -EBUSY;
977		goto out;
978	}
979
980	if (!local->ops->sched_scan_start) {
981		ret = -ENOTSUPP;
982		goto out;
983	}
984
985	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
986		if (!local->hw.wiphy->bands[i])
987			continue;
988
989		sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
990		if (!sched_scan_ies.ie[i]) {
991			ret = -ENOMEM;
992			goto out_free;
993		}
994
995		ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
996
997		sched_scan_ies.len[i] =
998			ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
999						 iebufsz, req->ie, req->ie_len,
1000						 i, (u32) -1, &chandef);
1001	}
1002
1003	ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1004	if (ret == 0)
1005		rcu_assign_pointer(local->sched_scan_sdata, sdata);
1006
1007out_free:
1008	while (i > 0)
1009		kfree(sched_scan_ies.ie[--i]);
1010out:
1011	mutex_unlock(&local->mtx);
1012	return ret;
1013}
1014
1015int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1016{
1017	struct ieee80211_local *local = sdata->local;
1018	int ret = 0;
1019
1020	mutex_lock(&local->mtx);
1021
1022	if (!local->ops->sched_scan_stop) {
1023		ret = -ENOTSUPP;
1024		goto out;
1025	}
1026
1027	if (rcu_access_pointer(local->sched_scan_sdata))
1028		drv_sched_scan_stop(local, sdata);
1029
1030out:
1031	mutex_unlock(&local->mtx);
1032
1033	return ret;
1034}
1035
1036void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1037{
1038	struct ieee80211_local *local = hw_to_local(hw);
1039
1040	trace_api_sched_scan_results(local);
1041
1042	cfg80211_sched_scan_results(hw->wiphy);
1043}
1044EXPORT_SYMBOL(ieee80211_sched_scan_results);
1045
1046void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1047{
1048	struct ieee80211_local *local =
1049		container_of(work, struct ieee80211_local,
1050			     sched_scan_stopped_work);
1051
1052	mutex_lock(&local->mtx);
1053
1054	if (!rcu_access_pointer(local->sched_scan_sdata)) {
1055		mutex_unlock(&local->mtx);
1056		return;
1057	}
1058
1059	rcu_assign_pointer(local->sched_scan_sdata, NULL);
1060
1061	mutex_unlock(&local->mtx);
1062
1063	cfg80211_sched_scan_stopped(local->hw.wiphy);
1064}
1065
1066void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1067{
1068	struct ieee80211_local *local = hw_to_local(hw);
1069
1070	trace_api_sched_scan_stopped(local);
1071
1072	ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1073}
1074EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1075