scan.c 29.0 KB
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/*
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 * Scanning implementation
 *
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 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
 * Copyright 2004, Instant802 Networks, Inc.
 * Copyright 2005, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/if_arp.h>
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#include <linux/etherdevice.h>
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#include <linux/rtnetlink.h>
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#include <linux/pm_qos.h>
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#include <net/sch_generic.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <net/mac80211.h>

#include "ieee80211_i.h"
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#include "driver-ops.h"
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#include "mesh.h"
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#define IEEE80211_PROBE_DELAY (HZ / 33)
#define IEEE80211_CHANNEL_TIME (HZ / 33)
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#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
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void ieee80211_rx_bss_put(struct ieee80211_local *local,
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			  struct ieee80211_bss *bss)
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{
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	if (!bss)
		return;
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	cfg80211_put_bss(local->hw.wiphy,
			 container_of((void *)bss, struct cfg80211_bss, priv));
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}

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static bool is_uapsd_supported(struct ieee802_11_elems *elems)
{
	u8 qos_info;

	if (elems->wmm_info && elems->wmm_info_len == 7
	    && elems->wmm_info[5] == 1)
		qos_info = elems->wmm_info[6];
	else if (elems->wmm_param && elems->wmm_param_len == 24
		 && elems->wmm_param[5] == 1)
		qos_info = elems->wmm_param[6];
	else
		/* no valid wmm information or parameter element found */
		return false;

	return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
}

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struct ieee80211_bss *
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ieee80211_bss_info_update(struct ieee80211_local *local,
			  struct ieee80211_rx_status *rx_status,
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			  struct ieee80211_mgmt *mgmt, size_t len,
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			  struct ieee802_11_elems *elems,
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			  struct ieee80211_channel *channel)
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{
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	bool beacon = ieee80211_is_beacon(mgmt->frame_control);
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	struct cfg80211_bss *cbss;
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	struct ieee80211_bss *bss;
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	int clen, srlen;
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	enum nl80211_bss_scan_width scan_width;
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	s32 signal = 0;

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	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
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		signal = rx_status->signal * 100;
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	else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
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		signal = (rx_status->signal * 100) / local->hw.max_signal;

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	scan_width = NL80211_BSS_CHAN_WIDTH_20;
	if (rx_status->flag & RX_FLAG_5MHZ)
		scan_width = NL80211_BSS_CHAN_WIDTH_5;
	if (rx_status->flag & RX_FLAG_10MHZ)
		scan_width = NL80211_BSS_CHAN_WIDTH_10;

	cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel,
					       scan_width, mgmt, len, signal,
					       GFP_ATOMIC);
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	if (!cbss)
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		return NULL;

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	bss = (void *)cbss->priv;
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	if (beacon)
		bss->device_ts_beacon = rx_status->device_timestamp;
	else
		bss->device_ts_presp = rx_status->device_timestamp;
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	if (elems->parse_error) {
		if (beacon)
			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
		else
			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
	} else {
		if (beacon)
			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
		else
			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
	}

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	/* save the ERP value so that it is available at association time */
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	if (elems->erp_info && (!elems->parse_error ||
				!(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
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		bss->erp_value = elems->erp_info[0];
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		bss->has_erp_value = true;
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		if (!elems->parse_error)
			bss->valid_data |= IEEE80211_BSS_VALID_ERP;
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	}

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	/* replace old supported rates if we get new values */
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	if (!elems->parse_error ||
	    !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
		srlen = 0;
		if (elems->supp_rates) {
			clen = IEEE80211_MAX_SUPP_RATES;
			if (clen > elems->supp_rates_len)
				clen = elems->supp_rates_len;
			memcpy(bss->supp_rates, elems->supp_rates, clen);
			srlen += clen;
		}
		if (elems->ext_supp_rates) {
			clen = IEEE80211_MAX_SUPP_RATES - srlen;
			if (clen > elems->ext_supp_rates_len)
				clen = elems->ext_supp_rates_len;
			memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
			       clen);
			srlen += clen;
		}
		if (srlen) {
			bss->supp_rates_len = srlen;
			if (!elems->parse_error)
				bss->valid_data |= IEEE80211_BSS_VALID_RATES;
		}
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	}

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	if (!elems->parse_error ||
	    !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
		bss->wmm_used = elems->wmm_param || elems->wmm_info;
		bss->uapsd_supported = is_uapsd_supported(elems);
		if (!elems->parse_error)
			bss->valid_data |= IEEE80211_BSS_VALID_WMM;
	}
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	if (beacon) {
		struct ieee80211_supported_band *sband =
			local->hw.wiphy->bands[rx_status->band];
		if (!(rx_status->flag & RX_FLAG_HT) &&
		    !(rx_status->flag & RX_FLAG_VHT))
			bss->beacon_rate =
				&sband->bitrates[rx_status->rate_idx];
	}

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	return bss;
}
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void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
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{
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	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
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	struct ieee80211_sub_if_data *sdata1, *sdata2;
	struct ieee80211_mgmt *mgmt = (void *)skb->data;
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	struct ieee80211_bss *bss;
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	u8 *elements;
	struct ieee80211_channel *channel;
	size_t baselen;
	struct ieee802_11_elems elems;

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	if (skb->len < 24 ||
	    (!ieee80211_is_probe_resp(mgmt->frame_control) &&
	     !ieee80211_is_beacon(mgmt->frame_control)))
		return;
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	sdata1 = rcu_dereference(local->scan_sdata);
	sdata2 = rcu_dereference(local->sched_scan_sdata);
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	if (likely(!sdata1 && !sdata2))
		return;
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	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
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		/* ignore ProbeResp to foreign address */
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		if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
		    (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
			return;
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		elements = mgmt->u.probe_resp.variable;
		baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
	} else {
		baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
		elements = mgmt->u.beacon.variable;
	}

	if (baselen > skb->len)
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		return;
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	ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
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	channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
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	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
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		return;
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	bss = ieee80211_bss_info_update(local, rx_status,
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					mgmt, skb->len, &elems,
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					channel);
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	if (bss)
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		ieee80211_rx_bss_put(local, bss);
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}

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static void
ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
			       enum nl80211_bss_scan_width scan_width)
{
	memset(chandef, 0, sizeof(*chandef));
	switch (scan_width) {
	case NL80211_BSS_CHAN_WIDTH_5:
		chandef->width = NL80211_CHAN_WIDTH_5;
		break;
	case NL80211_BSS_CHAN_WIDTH_10:
		chandef->width = NL80211_CHAN_WIDTH_10;
		break;
	default:
		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
		break;
	}
}

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/* return false if no more work */
static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
{
	struct cfg80211_scan_request *req = local->scan_req;
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	struct cfg80211_chan_def chandef;
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	enum ieee80211_band band;
	int i, ielen, n_chans;

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	if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
		return false;

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	do {
		if (local->hw_scan_band == IEEE80211_NUM_BANDS)
			return false;

		band = local->hw_scan_band;
		n_chans = 0;
		for (i = 0; i < req->n_channels; i++) {
			if (req->channels[i]->band == band) {
				local->hw_scan_req->channels[n_chans] =
							req->channels[i];
				n_chans++;
			}
		}

		local->hw_scan_band++;
	} while (!n_chans);

	local->hw_scan_req->n_channels = n_chans;
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	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
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	ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
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					 local->hw_scan_ies_bufsize,
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					 req->ie, req->ie_len, band,
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					 req->rates[band], &chandef);
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	local->hw_scan_req->ie_len = ielen;
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	local->hw_scan_req->no_cck = req->no_cck;
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	return true;
}

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static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
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{
	struct ieee80211_local *local = hw_to_local(hw);
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	bool hw_scan = local->ops->hw_scan;
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	bool was_scanning = local->scanning;
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	lockdep_assert_held(&local->mtx);
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	/*
	 * It's ok to abort a not-yet-running scan (that
	 * we have one at all will be verified by checking
	 * local->scan_req next), but not to complete it
	 * successfully.
	 */
	if (WARN_ON(!local->scanning && !aborted))
		aborted = true;
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	if (WARN_ON(!local->scan_req))
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		return;
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	if (hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
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		int rc;

		rc = drv_hw_scan(local,
			rcu_dereference_protected(local->scan_sdata,
						  lockdep_is_held(&local->mtx)),
			local->hw_scan_req);

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		if (rc == 0)
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			return;
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	}

	kfree(local->hw_scan_req);
	local->hw_scan_req = NULL;
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	if (local->scan_req != local->int_scan_req)
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		cfg80211_scan_done(local->scan_req, aborted);
	local->scan_req = NULL;
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	RCU_INIT_POINTER(local->scan_sdata, NULL);
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	local->scanning = 0;
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	local->scan_chandef.chan = NULL;
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	/* Set power back to normal operating levels. */
	ieee80211_hw_config(local, 0);
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	if (!hw_scan) {
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		ieee80211_configure_filter(local);
		drv_sw_scan_complete(local);
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		ieee80211_offchannel_return(local);
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	}
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	ieee80211_recalc_idle(local);
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	ieee80211_mlme_notify_scan_completed(local);
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	ieee80211_ibss_notify_scan_completed(local);
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	ieee80211_mesh_notify_scan_completed(local);
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	if (was_scanning)
		ieee80211_start_next_roc(local);
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}
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void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
{
	struct ieee80211_local *local = hw_to_local(hw);

	trace_api_scan_completed(local, aborted);

	set_bit(SCAN_COMPLETED, &local->scanning);
	if (aborted)
		set_bit(SCAN_ABORTED, &local->scanning);
	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
}
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EXPORT_SYMBOL(ieee80211_scan_completed);

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static int ieee80211_start_sw_scan(struct ieee80211_local *local)
{
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	/* Software scan is not supported in multi-channel cases */
	if (local->use_chanctx)
		return -EOPNOTSUPP;

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	/*
	 * Hardware/driver doesn't support hw_scan, so use software
	 * scanning instead. First send a nullfunc frame with power save
	 * bit on so that AP will buffer the frames for us while we are not
	 * listening, then send probe requests to each channel and wait for
	 * the responses. After all channels are scanned, tune back to the
	 * original channel and send a nullfunc frame with power save bit
	 * off to trigger the AP to send us all the buffered frames.
	 *
	 * Note that while local->sw_scanning is true everything else but
	 * nullfunc frames and probe requests will be dropped in
	 * ieee80211_tx_h_check_assoc().
	 */
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	drv_sw_scan_start(local);
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	local->leave_oper_channel_time = jiffies;
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	local->next_scan_state = SCAN_DECISION;
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	local->scan_channel_idx = 0;

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	ieee80211_offchannel_stop_vifs(local);
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	/* ensure nullfunc is transmitted before leaving operating channel */
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	ieee80211_flush_queues(local, NULL);
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	ieee80211_configure_filter(local);
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	/* We need to set power level at maximum rate for scanning. */
	ieee80211_hw_config(local, 0);

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	ieee80211_queue_delayed_work(&local->hw,
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				     &local->scan_work, 0);
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	return 0;
}

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static bool ieee80211_can_scan(struct ieee80211_local *local,
			       struct ieee80211_sub_if_data *sdata)
{
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	if (local->radar_detect_enabled)
		return false;

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	if (!list_empty(&local->roc_list))
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		return false;

	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
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	    sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
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		return false;

	return true;
}

void ieee80211_run_deferred_scan(struct ieee80211_local *local)
{
	lockdep_assert_held(&local->mtx);

	if (!local->scan_req || local->scanning)
		return;

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	if (!ieee80211_can_scan(local,
				rcu_dereference_protected(
					local->scan_sdata,
					lockdep_is_held(&local->mtx))))
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		return;

	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
				     round_jiffies_relative(0));
}
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static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
					    unsigned long *next_delay)
{
	int i;
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	struct ieee80211_sub_if_data *sdata;
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	enum ieee80211_band band = local->hw.conf.chandef.chan->band;
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	u32 tx_flags;

	tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
	if (local->scan_req->no_cck)
		tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
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	sdata = rcu_dereference_protected(local->scan_sdata,
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					  lockdep_is_held(&local->mtx));
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	for (i = 0; i < local->scan_req->n_ssids; i++)
		ieee80211_send_probe_req(
			sdata, NULL,
			local->scan_req->ssids[i].ssid,
			local->scan_req->ssids[i].ssid_len,
			local->scan_req->ie, local->scan_req->ie_len,
			local->scan_req->rates[band], false,
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			tx_flags, local->hw.conf.chandef.chan, true);
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	/*
	 * After sending probe requests, wait for probe responses
	 * on the channel.
	 */
	*next_delay = IEEE80211_CHANNEL_TIME;
	local->next_scan_state = SCAN_DECISION;
}

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static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
				  struct cfg80211_scan_request *req)
{
	struct ieee80211_local *local = sdata->local;
	int rc;

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	lockdep_assert_held(&local->mtx);

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	if (local->scan_req)
		return -EBUSY;

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	if (!ieee80211_can_scan(local, sdata)) {
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		/* wait for the work to finish/time out */
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		local->scan_req = req;
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		rcu_assign_pointer(local->scan_sdata, sdata);
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		return 0;
	}

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	if (local->ops->hw_scan) {
		u8 *ies;

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		local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
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		local->hw_scan_req = kmalloc(
				sizeof(*local->hw_scan_req) +
				req->n_channels * sizeof(req->channels[0]) +
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				local->hw_scan_ies_bufsize, GFP_KERNEL);
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		if (!local->hw_scan_req)
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			return -ENOMEM;

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		local->hw_scan_req->ssids = req->ssids;
		local->hw_scan_req->n_ssids = req->n_ssids;
		ies = (u8 *)local->hw_scan_req +
			sizeof(*local->hw_scan_req) +
			req->n_channels * sizeof(req->channels[0]);
		local->hw_scan_req->ie = ies;
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		local->hw_scan_req->flags = req->flags;
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		local->hw_scan_band = 0;
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		/*
		 * After allocating local->hw_scan_req, we must
		 * go through until ieee80211_prep_hw_scan(), so
		 * anything that might be changed here and leave
		 * this function early must not go after this
		 * allocation.
		 */
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	}

	local->scan_req = req;
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	rcu_assign_pointer(local->scan_sdata, sdata);
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	if (local->ops->hw_scan) {
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		__set_bit(SCAN_HW_SCANNING, &local->scanning);
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	} else if ((req->n_channels == 1) &&
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		   (req->channels[0] == local->_oper_chandef.chan)) {
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		/*
		 * If we are scanning only on the operating channel
		 * then we do not need to stop normal activities
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		 */
		unsigned long next_delay;

		__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);

		ieee80211_recalc_idle(local);

		/* Notify driver scan is starting, keep order of operations
		 * same as normal software scan, in case that matters. */
		drv_sw_scan_start(local);

		ieee80211_configure_filter(local); /* accept probe-responses */

		/* We need to ensure power level is at max for scanning. */
		ieee80211_hw_config(local, 0);

		if ((req->channels[0]->flags &
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		     IEEE80211_CHAN_NO_IR) ||
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		    !local->scan_req->n_ssids) {
			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
		} else {
			ieee80211_scan_state_send_probe(local, &next_delay);
			next_delay = IEEE80211_CHANNEL_TIME;
		}

		/* Now, just wait a bit and we are all done! */
		ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
					     next_delay);
		return 0;
	} else {
		/* Do normal software scan */
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		__set_bit(SCAN_SW_SCANNING, &local->scanning);
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	}
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	ieee80211_recalc_idle(local);
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	if (local->ops->hw_scan) {
		WARN_ON(!ieee80211_prep_hw_scan(local));
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		rc = drv_hw_scan(local, sdata, local->hw_scan_req);
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	} else
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		rc = ieee80211_start_sw_scan(local);

	if (rc) {
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		kfree(local->hw_scan_req);
		local->hw_scan_req = NULL;
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		local->scanning = 0;
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		ieee80211_recalc_idle(local);

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		local->scan_req = NULL;
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		RCU_INIT_POINTER(local->scan_sdata, NULL);
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	}

	return rc;
}

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static unsigned long
ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
{
	/*
	 * TODO: channel switching also consumes quite some time,
	 * add that delay as well to get a better estimation
	 */
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	if (chan->flags & IEEE80211_CHAN_NO_IR)
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		return IEEE80211_PASSIVE_CHANNEL_TIME;
	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
}

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static void ieee80211_scan_state_decision(struct ieee80211_local *local,
					  unsigned long *next_delay)
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{
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	bool associated = false;
584 585
	bool tx_empty = true;
	bool bad_latency;
586
	struct ieee80211_sub_if_data *sdata;
587
	struct ieee80211_channel *next_chan;
588
	enum mac80211_scan_state next_scan_state;
589

590 591 592 593 594
	/*
	 * check if at least one STA interface is associated,
	 * check if at least one STA interface has pending tx frames
	 * and grab the lowest used beacon interval
	 */
595 596
	mutex_lock(&local->iflist_mtx);
	list_for_each_entry(sdata, &local->interfaces, list) {
597
		if (!ieee80211_sdata_running(sdata))
598 599 600 601 602
			continue;

		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
			if (sdata->u.mgd.associated) {
				associated = true;
603 604 605 606 607

				if (!qdisc_all_tx_empty(sdata->dev)) {
					tx_empty = false;
					break;
				}
608 609 610 611 612
			}
		}
	}
	mutex_unlock(&local->iflist_mtx);

613 614
	next_chan = local->scan_req->channels[local->scan_channel_idx];

615
	/*
616 617 618 619
	 * we're currently scanning a different channel, let's
	 * see if we can scan another channel without interfering
	 * with the current traffic situation.
	 *
620
	 * Keep good latency, do not stay off-channel more than 125 ms.
621 622
	 */

623
	bad_latency = time_after(jiffies +
624 625
				 ieee80211_scan_get_channel_time(next_chan),
				 local->leave_oper_channel_time + HZ / 8);
626

627 628 629 630 631
	if (associated && !tx_empty) {
		if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
			next_scan_state = SCAN_ABORT;
		else
			next_scan_state = SCAN_SUSPEND;
632
	} else if (associated && bad_latency) {
633 634 635 636 637 638
		next_scan_state = SCAN_SUSPEND;
	} else {
		next_scan_state = SCAN_SET_CHANNEL;
	}

	local->next_scan_state = next_scan_state;
639

640
	*next_delay = 0;
641 642
}

643 644 645 646 647
static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
					     unsigned long *next_delay)
{
	int skip;
	struct ieee80211_channel *chan;
648
	enum nl80211_bss_scan_width oper_scan_width;
649

H
Helmut Schaa 已提交
650 651 652
	skip = 0;
	chan = local->scan_req->channels[local->scan_channel_idx];

653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675
	local->scan_chandef.chan = chan;
	local->scan_chandef.center_freq1 = chan->center_freq;
	local->scan_chandef.center_freq2 = 0;
	switch (local->scan_req->scan_width) {
	case NL80211_BSS_CHAN_WIDTH_5:
		local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
		break;
	case NL80211_BSS_CHAN_WIDTH_10:
		local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
		break;
	case NL80211_BSS_CHAN_WIDTH_20:
		/* If scanning on oper channel, use whatever channel-type
		 * is currently in use.
		 */
		oper_scan_width = cfg80211_chandef_to_scan_width(
					&local->_oper_chandef);
		if (chan == local->_oper_chandef.chan &&
		    oper_scan_width == local->scan_req->scan_width)
			local->scan_chandef = local->_oper_chandef;
		else
			local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
		break;
	}
676

677 678
	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
		skip = 1;
H
Helmut Schaa 已提交
679 680 681 682

	/* advance state machine to next channel/band */
	local->scan_channel_idx++;

683 684 685
	if (skip) {
		/* if we skip this channel return to the decision state */
		local->next_scan_state = SCAN_DECISION;
686
		return;
687
	}
H
Helmut Schaa 已提交
688 689 690 691 692 693 694 695 696 697 698

	/*
	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
	 * (which unfortunately doesn't say _why_ step a) is done,
	 * but it waits for the probe delay or until a frame is
	 * received - and the received frame would update the NAV).
	 * For now, we do not support waiting until a frame is
	 * received.
	 *
	 * In any case, it is not necessary for a passive scan.
	 */
699
	if (chan->flags & IEEE80211_CHAN_NO_IR ||
H
Helmut Schaa 已提交
700 701
	    !local->scan_req->n_ssids) {
		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
702
		local->next_scan_state = SCAN_DECISION;
703
		return;
H
Helmut Schaa 已提交
704 705
	}

706
	/* active scan, send probes */
H
Helmut Schaa 已提交
707
	*next_delay = IEEE80211_PROBE_DELAY;
708
	local->next_scan_state = SCAN_SEND_PROBE;
H
Helmut Schaa 已提交
709 710
}

711 712 713 714
static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
					 unsigned long *next_delay)
{
	/* switch back to the operating channel */
715
	local->scan_chandef.chan = NULL;
716 717
	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);

718 719
	/* disable PS */
	ieee80211_offchannel_return(local);
720 721 722 723 724 725 726 727 728

	*next_delay = HZ / 5;
	/* afterwards, resume scan & go to next channel */
	local->next_scan_state = SCAN_RESUME;
}

static void ieee80211_scan_state_resume(struct ieee80211_local *local,
					unsigned long *next_delay)
{
729
	ieee80211_offchannel_stop_vifs(local);
730 731

	if (local->ops->flush) {
732
		ieee80211_flush_queues(local, NULL);
733 734 735 736 737 738 739 740
		*next_delay = 0;
	} else
		*next_delay = HZ / 10;

	/* remember when we left the operating channel */
	local->leave_oper_channel_time = jiffies;

	/* advance to the next channel to be scanned */
741
	local->next_scan_state = SCAN_SET_CHANNEL;
742 743
}

744
void ieee80211_scan_work(struct work_struct *work)
745 746 747
{
	struct ieee80211_local *local =
		container_of(work, struct ieee80211_local, scan_work.work);
748
	struct ieee80211_sub_if_data *sdata;
749
	unsigned long next_delay = 0;
750
	bool aborted;
751

752
	mutex_lock(&local->mtx);
753

754 755
	sdata = rcu_dereference_protected(local->scan_sdata,
					  lockdep_is_held(&local->mtx));
756

757 758 759 760 761 762
	/* When scanning on-channel, the first-callback means completed. */
	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
		goto out_complete;
	}

763
	if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
764
		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
765
		goto out_complete;
766 767
	}

768 769
	if (!sdata || !local->scan_req)
		goto out;
770

771
	if (local->scan_req && !local->scanning) {
772 773 774 775
		struct cfg80211_scan_request *req = local->scan_req;
		int rc;

		local->scan_req = NULL;
M
Monam Agarwal 已提交
776
		RCU_INIT_POINTER(local->scan_sdata, NULL);
777 778

		rc = __ieee80211_start_scan(sdata, req);
779
		if (rc) {
780 781
			/* need to complete scan in cfg80211 */
			local->scan_req = req;
782 783 784 785
			aborted = true;
			goto out_complete;
		} else
			goto out;
786 787
	}

788 789 790 791 792
	/*
	 * as long as no delay is required advance immediately
	 * without scheduling a new work
	 */
	do {
793 794 795 796 797
		if (!ieee80211_sdata_running(sdata)) {
			aborted = true;
			goto out_complete;
		}

798
		switch (local->next_scan_state) {
799
		case SCAN_DECISION:
800 801 802 803 804 805
			/* if no more bands/channels left, complete scan */
			if (local->scan_channel_idx >= local->scan_req->n_channels) {
				aborted = false;
				goto out_complete;
			}
			ieee80211_scan_state_decision(local, &next_delay);
806
			break;
807 808 809
		case SCAN_SET_CHANNEL:
			ieee80211_scan_state_set_channel(local, &next_delay);
			break;
810 811 812
		case SCAN_SEND_PROBE:
			ieee80211_scan_state_send_probe(local, &next_delay);
			break;
813 814
		case SCAN_SUSPEND:
			ieee80211_scan_state_suspend(local, &next_delay);
815
			break;
816 817
		case SCAN_RESUME:
			ieee80211_scan_state_resume(local, &next_delay);
818
			break;
819 820 821
		case SCAN_ABORT:
			aborted = true;
			goto out_complete;
822 823
		}
	} while (next_delay == 0);
824

825
	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
826
	goto out;
827 828

out_complete:
829
	__ieee80211_scan_completed(&local->hw, aborted);
830 831
out:
	mutex_unlock(&local->mtx);
832 833
}

834 835
int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
			   struct cfg80211_scan_request *req)
836
{
837
	int res;
838

839
	mutex_lock(&sdata->local->mtx);
840
	res = __ieee80211_start_scan(sdata, req);
841
	mutex_unlock(&sdata->local->mtx);
842

843
	return res;
844 845
}

S
Stanislaw Gruszka 已提交
846 847
int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
				const u8 *ssid, u8 ssid_len,
848 849
				struct ieee80211_channel *chan,
				enum nl80211_bss_scan_width scan_width)
850 851
{
	struct ieee80211_local *local = sdata->local;
852
	int ret = -EBUSY;
853
	enum ieee80211_band band;
854

855
	mutex_lock(&local->mtx);
856

857 858 859
	/* busy scanning */
	if (local->scan_req)
		goto unlock;
J
Johannes Berg 已提交
860

J
Johannes Berg 已提交
861 862
	/* fill internal scan request */
	if (!chan) {
S
Stanislaw Gruszka 已提交
863 864
		int i, max_n;
		int n_ch = 0;
J
Johannes Berg 已提交
865 866 867 868

		for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
			if (!local->hw.wiphy->bands[band])
				continue;
S
Stanislaw Gruszka 已提交
869 870 871 872

			max_n = local->hw.wiphy->bands[band]->n_channels;
			for (i = 0; i < max_n; i++) {
				struct ieee80211_channel *tmp_ch =
J
Johannes Berg 已提交
873
				    &local->hw.wiphy->bands[band]->channels[i];
S
Stanislaw Gruszka 已提交
874

875
				if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
S
Stanislaw Gruszka 已提交
876 877 878 879 880
						     IEEE80211_CHAN_DISABLED))
					continue;

				local->int_scan_req->channels[n_ch] = tmp_ch;
				n_ch++;
J
Johannes Berg 已提交
881 882 883
			}
		}

S
Stanislaw Gruszka 已提交
884 885 886 887
		if (WARN_ON_ONCE(n_ch == 0))
			goto unlock;

		local->int_scan_req->n_channels = n_ch;
J
Johannes Berg 已提交
888
	} else {
889
		if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR |
S
Stanislaw Gruszka 已提交
890 891 892
						IEEE80211_CHAN_DISABLED)))
			goto unlock;

J
Johannes Berg 已提交
893 894 895 896 897 898
		local->int_scan_req->channels[0] = chan;
		local->int_scan_req->n_channels = 1;
	}

	local->int_scan_req->ssids = &local->scan_ssid;
	local->int_scan_req->n_ssids = 1;
899
	local->int_scan_req->scan_width = scan_width;
900 901
	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
	local->int_scan_req->ssids[0].ssid_len = ssid_len;
J
Johannes Berg 已提交
902

903
	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
904
 unlock:
905
	mutex_unlock(&local->mtx);
906
	return ret;
907
}
908

909 910 911
/*
 * Only call this function when a scan can't be queued -- under RTNL.
 */
912 913 914
void ieee80211_scan_cancel(struct ieee80211_local *local)
{
	/*
915
	 * We are canceling software scan, or deferred scan that was not
916 917 918 919 920 921 922 923 924 925 926
	 * yet really started (see __ieee80211_start_scan ).
	 *
	 * Regarding hardware scan:
	 * - we can not call  __ieee80211_scan_completed() as when
	 *   SCAN_HW_SCANNING bit is set this function change
	 *   local->hw_scan_req to operate on 5G band, what race with
	 *   driver which can use local->hw_scan_req
	 *
	 * - we can not cancel scan_work since driver can schedule it
	 *   by ieee80211_scan_completed(..., true) to finish scan
	 *
927 928 929
	 * Hence we only call the cancel_hw_scan() callback, but the low-level
	 * driver is still responsible for calling ieee80211_scan_completed()
	 * after the scan was completed/aborted.
930
	 */
931

932
	mutex_lock(&local->mtx);
933 934 935
	if (!local->scan_req)
		goto out;

936 937 938 939 940 941 942 943 944 945 946
	/*
	 * We have a scan running and the driver already reported completion,
	 * but the worker hasn't run yet or is stuck on the mutex - mark it as
	 * cancelled.
	 */
	if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
	    test_bit(SCAN_COMPLETED, &local->scanning)) {
		set_bit(SCAN_HW_CANCELLED, &local->scanning);
		goto out;
	}

947
	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
948 949 950 951 952
		/*
		 * Make sure that __ieee80211_scan_completed doesn't trigger a
		 * scan on another band.
		 */
		set_bit(SCAN_HW_CANCELLED, &local->scanning);
953
		if (local->ops->cancel_hw_scan)
954 955 956
			drv_cancel_hw_scan(local,
				rcu_dereference_protected(local->scan_sdata,
						lockdep_is_held(&local->mtx)));
957
		goto out;
958
	}
959 960 961 962 963 964 965 966

	/*
	 * If the work is currently running, it must be blocked on
	 * the mutex, but we'll set scan_sdata = NULL and it'll
	 * simply exit once it acquires the mutex.
	 */
	cancel_delayed_work(&local->scan_work);
	/* and clean up */
967
	__ieee80211_scan_completed(&local->hw, true);
968
out:
969
	mutex_unlock(&local->mtx);
970
}
971

972 973
int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
					struct cfg80211_sched_scan_request *req)
974 975
{
	struct ieee80211_local *local = sdata->local;
D
David Spinadel 已提交
976
	struct ieee80211_sched_scan_ies sched_scan_ies = {};
977
	struct cfg80211_chan_def chandef;
978 979
	int ret, i, iebufsz;

D
David Spinadel 已提交
980
	iebufsz = local->scan_ies_len + req->ie_len;
981

982
	lockdep_assert_held(&local->mtx);
983

984 985
	if (!local->ops->sched_scan_start)
		return -ENOTSUPP;
986 987

	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
988 989 990
		if (!local->hw.wiphy->bands[i])
			continue;

991
		sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
992
		if (!sched_scan_ies.ie[i]) {
993 994 995 996
			ret = -ENOMEM;
			goto out_free;
		}

997 998
		ieee80211_prepare_scan_chandef(&chandef, req->scan_width);

999 1000
		sched_scan_ies.len[i] =
			ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
1001
						 iebufsz, req->ie, req->ie_len,
1002
						 i, (u32) -1, &chandef);
1003 1004
	}

1005
	ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1006
	if (ret == 0) {
1007
		rcu_assign_pointer(local->sched_scan_sdata, sdata);
1008 1009
		local->sched_scan_req = req;
	}
1010 1011 1012

out_free:
	while (i > 0)
1013
		kfree(sched_scan_ies.ie[--i]);
1014 1015 1016

	if (ret) {
		/* Clean in case of failure after HW restart or upon resume. */
M
Monam Agarwal 已提交
1017
		RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038
		local->sched_scan_req = NULL;
	}

	return ret;
}

int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
				       struct cfg80211_sched_scan_request *req)
{
	struct ieee80211_local *local = sdata->local;
	int ret;

	mutex_lock(&local->mtx);

	if (rcu_access_pointer(local->sched_scan_sdata)) {
		mutex_unlock(&local->mtx);
		return -EBUSY;
	}

	ret = __ieee80211_request_sched_scan_start(sdata, req);

1039
	mutex_unlock(&local->mtx);
1040 1041 1042
	return ret;
}

1043
int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1044 1045
{
	struct ieee80211_local *local = sdata->local;
1046
	int ret = 0;
1047

1048
	mutex_lock(&local->mtx);
1049 1050 1051 1052 1053 1054

	if (!local->ops->sched_scan_stop) {
		ret = -ENOTSUPP;
		goto out;
	}

1055 1056 1057
	/* We don't want to restart sched scan anymore. */
	local->sched_scan_req = NULL;

1058
	if (rcu_access_pointer(local->sched_scan_sdata)) {
1059
		ret = drv_sched_scan_stop(local, sdata);
1060 1061 1062
		if (!ret)
			rcu_assign_pointer(local->sched_scan_sdata, NULL);
	}
1063
out:
1064
	mutex_unlock(&local->mtx);
1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078

	return ret;
}

void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
{
	struct ieee80211_local *local = hw_to_local(hw);

	trace_api_sched_scan_results(local);

	cfg80211_sched_scan_results(hw->wiphy);
}
EXPORT_SYMBOL(ieee80211_sched_scan_results);

1079
void ieee80211_sched_scan_end(struct ieee80211_local *local)
1080 1081 1082
{
	mutex_lock(&local->mtx);

1083
	if (!rcu_access_pointer(local->sched_scan_sdata)) {
1084 1085 1086 1087
		mutex_unlock(&local->mtx);
		return;
	}

M
Monam Agarwal 已提交
1088
	RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1089

1090 1091 1092
	/* If sched scan was aborted by the driver. */
	local->sched_scan_req = NULL;

1093 1094 1095 1096 1097
	mutex_unlock(&local->mtx);

	cfg80211_sched_scan_stopped(local->hw.wiphy);
}

1098 1099 1100 1101 1102 1103 1104 1105 1106
void ieee80211_sched_scan_stopped_work(struct work_struct *work)
{
	struct ieee80211_local *local =
		container_of(work, struct ieee80211_local,
			     sched_scan_stopped_work);

	ieee80211_sched_scan_end(local);
}

1107 1108 1109 1110 1111 1112
void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
{
	struct ieee80211_local *local = hw_to_local(hw);

	trace_api_sched_scan_stopped(local);

1113
	schedule_work(&local->sched_scan_stopped_work);
1114 1115
}
EXPORT_SYMBOL(ieee80211_sched_scan_stopped);