X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=net%2Fmac80211%2Fscan.c;h=b822dce9786706e65a30480aa97b1cfd031211e6;hb=070bb5477fb4029131aad4941d7aaf0093db0c38;hp=f883ab9f1e6e436de1f4a311963410a341a931cd;hpb=00d3f14cf9f12c21428121026a5e1d5f65926447;p=safe%2Fjmp%2Flinux-2.6

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index f883ab9..b822dce 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -12,35 +12,35 @@
  * published by the Free Software Foundation.
  */
 
-/* TODO: figure out how to avoid that the "current BSS" expires */
-
-#include <linux/wireless.h>
 #include <linux/if_arp.h>
 #include <linux/rtnetlink.h>
 #include <net/mac80211.h>
-#include <net/iw_handler.h>
 
 #include "ieee80211_i.h"
+#include "driver-ops.h"
 #include "mesh.h"
 
 #define IEEE80211_PROBE_DELAY (HZ / 33)
 #define IEEE80211_CHANNEL_TIME (HZ / 33)
-#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5)
+#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
 
 struct ieee80211_bss *
 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
 		     u8 *ssid, u8 ssid_len)
 {
-	return (void *)cfg80211_get_bss(local->hw.wiphy,
-					ieee80211_get_channel(local->hw.wiphy,
-							      freq),
-					bssid, ssid, ssid_len,
-					0, 0);
+	struct cfg80211_bss *cbss;
+
+	cbss = cfg80211_get_bss(local->hw.wiphy,
+				ieee80211_get_channel(local->hw.wiphy, freq),
+				bssid, ssid, ssid_len, 0, 0);
+	if (!cbss)
+		return NULL;
+	return (void *)cbss->priv;
 }
 
 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
 {
-	struct ieee80211_bss *bss = (void *)cbss;
+	struct ieee80211_bss *bss = (void *)cbss->priv;
 
 	kfree(bss_mesh_id(bss));
 	kfree(bss_mesh_cfg(bss));
@@ -49,7 +49,26 @@ static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
 void ieee80211_rx_bss_put(struct ieee80211_local *local,
 			  struct ieee80211_bss *bss)
 {
-	cfg80211_put_bss((struct cfg80211_bss *)bss);
+	if (!bss)
+		return;
+	cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
+}
+
+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;
 }
 
 struct ieee80211_bss *
@@ -61,27 +80,24 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
 			  struct ieee80211_channel *channel,
 			  bool beacon)
 {
+	struct cfg80211_bss *cbss;
 	struct ieee80211_bss *bss;
 	int clen;
-	enum cfg80211_signal_type sigtype = CFG80211_SIGNAL_TYPE_NONE;
 	s32 signal = 0;
 
-	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
-		sigtype = CFG80211_SIGNAL_TYPE_MBM;
+	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
 		signal = rx_status->signal * 100;
-	} else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) {
-		sigtype = CFG80211_SIGNAL_TYPE_UNSPEC;
+	else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
 		signal = (rx_status->signal * 100) / local->hw.max_signal;
-	}
 
-	bss = (void *)cfg80211_inform_bss_frame(local->hw.wiphy, channel,
-						mgmt, len, signal, sigtype,
-						GFP_ATOMIC);
+	cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
+					 mgmt, len, signal, GFP_ATOMIC);
 
-	if (!bss)
+	if (!cbss)
 		return NULL;
 
-	bss->cbss.free_priv = ieee80211_rx_bss_free;
+	cbss->free_priv = ieee80211_rx_bss_free;
+	bss = (void *)cbss->priv;
 
 	/* save the ERP value so that it is available at association time */
 	if (elems->erp_info && elems->erp_info_len >= 1) {
@@ -95,10 +111,6 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
 		bss->dtim_period = tim_ie->dtim_period;
 	}
 
-	/* set default value for buggy APs */
-	if (!elems->tim || bss->dtim_period == 0)
-		bss->dtim_period = 1;
-
 	bss->supp_rates_len = 0;
 	if (elems->supp_rates) {
 		clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
@@ -118,6 +130,7 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
 	}
 
 	bss->wmm_used = elems->wmm_param || elems->wmm_info;
+	bss->uapsd_supported = is_uapsd_supported(elems);
 
 	if (!beacon)
 		bss->last_probe_resp = jiffies;
@@ -125,23 +138,10 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
 	return bss;
 }
 
-void ieee80211_rx_bss_remove(struct ieee80211_sub_if_data *sdata, u8 *bssid,
-			     int freq, u8 *ssid, u8 ssid_len)
-{
-	struct ieee80211_bss *bss;
-	struct ieee80211_local *local = sdata->local;
-
-	bss = ieee80211_rx_bss_get(local, bssid, freq, ssid, ssid_len);
-	if (bss) {
-		cfg80211_unlink_bss(local->hw.wiphy, (void *)bss);
-		ieee80211_rx_bss_put(local, bss);
-	}
-}
-
 ieee80211_rx_result
-ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
-		  struct ieee80211_rx_status *rx_status)
+ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 {
+	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 	struct ieee80211_mgmt *mgmt;
 	struct ieee80211_bss *bss;
 	u8 *elements;
@@ -167,7 +167,7 @@ ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
 	presp = ieee80211_is_probe_resp(fc);
 	if (presp) {
 		/* ignore ProbeResp to foreign address */
-		if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
+		if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
 			return RX_DROP_MONITOR;
 
 		presp = true;
@@ -207,304 +207,500 @@ ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
 	return RX_QUEUED;
 }
 
-void ieee80211_send_nullfunc(struct ieee80211_local *local,
-				    struct ieee80211_sub_if_data *sdata,
-				    int powersave)
+/* return false if no more work */
+static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 {
-	struct sk_buff *skb;
-	struct ieee80211_hdr *nullfunc;
-	__le16 fc;
+	struct cfg80211_scan_request *req = local->scan_req;
+	enum ieee80211_band band;
+	int i, ielen, n_chans;
+
+	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++;
+			}
+		}
 
-	skb = dev_alloc_skb(local->hw.extra_tx_headroom + 24);
-	if (!skb) {
-		printk(KERN_DEBUG "%s: failed to allocate buffer for nullfunc "
-		       "frame\n", sdata->dev->name);
-		return;
-	}
-	skb_reserve(skb, local->hw.extra_tx_headroom);
-
-	nullfunc = (struct ieee80211_hdr *) skb_put(skb, 24);
-	memset(nullfunc, 0, 24);
-	fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_NULLFUNC |
-			 IEEE80211_FCTL_TODS);
-	if (powersave)
-		fc |= cpu_to_le16(IEEE80211_FCTL_PM);
-	nullfunc->frame_control = fc;
-	memcpy(nullfunc->addr1, sdata->u.sta.bssid, ETH_ALEN);
-	memcpy(nullfunc->addr2, sdata->dev->dev_addr, ETH_ALEN);
-	memcpy(nullfunc->addr3, sdata->u.sta.bssid, ETH_ALEN);
-
-	ieee80211_tx_skb(sdata, skb, 0);
+		local->hw_scan_band++;
+	} while (!n_chans);
+
+	local->hw_scan_req->n_channels = n_chans;
+
+	ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
+					 req->ie, req->ie_len, band);
+	local->hw_scan_req->ie_len = ielen;
+
+	return true;
 }
 
 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
-	struct ieee80211_sub_if_data *sdata;
+	bool was_hw_scan;
+
+	mutex_lock(&local->scan_mtx);
+
+	/*
+	 * 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;
 
-	if (WARN_ON(!local->hw_scanning && !local->sw_scanning))
+	if (WARN_ON(!local->scan_req)) {
+		mutex_unlock(&local->scan_mtx);
 		return;
+	}
 
-	if (WARN_ON(!local->scan_req))
+	was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
+	if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
+		ieee80211_queue_delayed_work(&local->hw,
+					     &local->scan_work, 0);
+		mutex_unlock(&local->scan_mtx);
 		return;
+	}
+
+	kfree(local->hw_scan_req);
+	local->hw_scan_req = NULL;
 
-	if (local->scan_req != &local->int_scan_req)
+	if (local->scan_req != local->int_scan_req)
 		cfg80211_scan_done(local->scan_req, aborted);
 	local->scan_req = NULL;
+	local->scan_sdata = NULL;
 
-	local->last_scan_completed = jiffies;
+	local->scanning = 0;
+	local->scan_channel = NULL;
 
-	if (local->hw_scanning) {
-		local->hw_scanning = false;
-		/*
-		 * Somebody might have requested channel change during scan
-		 * that we won't have acted upon, try now. ieee80211_hw_config
-		 * will set the flag based on actual changes.
-		 */
-		ieee80211_hw_config(local, 0);
-		goto done;
-	}
+	/* we only have to protect scan_req and hw/sw scan */
+	mutex_unlock(&local->scan_mtx);
 
-	local->sw_scanning = false;
 	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+	if (was_hw_scan)
+		goto done;
 
-	netif_tx_lock_bh(local->mdev);
-	netif_addr_lock(local->mdev);
-	local->filter_flags &= ~FIF_BCN_PRBRESP_PROMISC;
-	local->ops->configure_filter(local_to_hw(local),
-				     FIF_BCN_PRBRESP_PROMISC,
-				     &local->filter_flags,
-				     local->mdev->mc_count,
-				     local->mdev->mc_list);
-
-	netif_addr_unlock(local->mdev);
-	netif_tx_unlock_bh(local->mdev);
+	ieee80211_configure_filter(local);
 
-	mutex_lock(&local->iflist_mtx);
-	list_for_each_entry(sdata, &local->interfaces, list) {
-		if (!netif_running(sdata->dev))
-			continue;
+	drv_sw_scan_complete(local);
 
-		/* Tell AP we're back */
-		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
-			if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) {
-				ieee80211_send_nullfunc(local, sdata, 0);
-				netif_tx_wake_all_queues(sdata->dev);
-			}
-		} else
-			netif_tx_wake_all_queues(sdata->dev);
-
-		/* re-enable beaconing */
-		if (sdata->vif.type == NL80211_IFTYPE_AP ||
-		    sdata->vif.type == NL80211_IFTYPE_ADHOC ||
-		    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
-			ieee80211_if_config(sdata,
-					    IEEE80211_IFCC_BEACON_ENABLED);
-	}
-	mutex_unlock(&local->iflist_mtx);
+	ieee80211_offchannel_return(local, true);
 
  done:
+	ieee80211_recalc_idle(local);
 	ieee80211_mlme_notify_scan_completed(local);
+	ieee80211_ibss_notify_scan_completed(local);
 	ieee80211_mesh_notify_scan_completed(local);
+	ieee80211_queue_work(&local->hw, &local->work_work);
 }
 EXPORT_SYMBOL(ieee80211_scan_completed);
 
-void ieee80211_scan_work(struct work_struct *work)
+static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 {
-	struct ieee80211_local *local =
-		container_of(work, struct ieee80211_local, scan_work.work);
-	struct ieee80211_sub_if_data *sdata = local->scan_sdata;
-	struct ieee80211_channel *chan;
-	int skip, i;
-	unsigned long next_delay = 0;
-
 	/*
-	 * Avoid re-scheduling when the sdata is going away.
+	 * 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().
 	 */
-	if (!netif_running(sdata->dev))
-		return;
+	drv_sw_scan_start(local);
 
-	switch (local->scan_state) {
-	case SCAN_SET_CHANNEL:
-		/* if no more bands/channels left, complete scan */
-		if (local->scan_channel_idx >= local->scan_req->n_channels) {
-			ieee80211_scan_completed(local_to_hw(local), false);
-			return;
-		}
-		skip = 0;
-		chan = local->scan_req->channels[local->scan_channel_idx];
-
-		if (chan->flags & IEEE80211_CHAN_DISABLED ||
-		    (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
-		     chan->flags & IEEE80211_CHAN_NO_IBSS))
-			skip = 1;
-
-		if (!skip) {
-			local->scan_channel = chan;
-			if (ieee80211_hw_config(local,
-						IEEE80211_CONF_CHANGE_CHANNEL))
-				skip = 1;
-		}
+	ieee80211_offchannel_stop_beaconing(local);
 
-		/* advance state machine to next channel/band */
-		local->scan_channel_idx++;
+	local->next_scan_state = SCAN_DECISION;
+	local->scan_channel_idx = 0;
 
-		if (skip)
-			break;
+	drv_flush(local, false);
 
-		next_delay = IEEE80211_PROBE_DELAY +
-			     usecs_to_jiffies(local->hw.channel_change_time);
-		local->scan_state = SCAN_SEND_PROBE;
-		break;
-	case SCAN_SEND_PROBE:
-		next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
-		local->scan_state = SCAN_SET_CHANNEL;
+	ieee80211_configure_filter(local);
 
-		if (local->scan_channel->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
-		    !local->scan_req->n_ssids)
-			break;
-		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);
-		next_delay = IEEE80211_CHANNEL_TIME;
-		break;
-	}
+	ieee80211_queue_delayed_work(&local->hw,
+				     &local->scan_work,
+				     IEEE80211_CHANNEL_TIME);
 
-	queue_delayed_work(local->hw.workqueue, &local->scan_work,
-			   next_delay);
+	return 0;
 }
 
 
-int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,
-			 struct cfg80211_scan_request *req)
+static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
+				  struct cfg80211_scan_request *req)
 {
-	struct ieee80211_local *local = scan_sdata->local;
-	struct ieee80211_sub_if_data *sdata;
-
-	if (!req)
-		return -EINVAL;
+	struct ieee80211_local *local = sdata->local;
+	int rc;
 
-	if (local->scan_req && local->scan_req != req)
+	if (local->scan_req)
 		return -EBUSY;
 
+	if (!list_empty(&local->work_list)) {
+		/* wait for the work to finish/time out */
+		local->scan_req = req;
+		local->scan_sdata = sdata;
+		return 0;
+	}
+
+	if (local->ops->hw_scan) {
+		u8 *ies;
+
+		local->hw_scan_req = kmalloc(
+				sizeof(*local->hw_scan_req) +
+				req->n_channels * sizeof(req->channels[0]) +
+				2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
+				req->ie_len, GFP_KERNEL);
+		if (!local->hw_scan_req)
+			return -ENOMEM;
+
+		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;
+
+		local->hw_scan_band = 0;
+
+		/*
+		 * 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.
+		 */
+	}
+
 	local->scan_req = req;
+	local->scan_sdata = sdata;
 
-	/* MLME-SCAN.request (page 118)  page 144 (11.1.3.1)
-	 * BSSType: INFRASTRUCTURE, INDEPENDENT, ANY_BSS
-	 * BSSID: MACAddress
-	 * SSID
-	 * ScanType: ACTIVE, PASSIVE
-	 * ProbeDelay: delay (in microseconds) to be used prior to transmitting
-	 *    a Probe frame during active scanning
-	 * ChannelList
-	 * MinChannelTime (>= ProbeDelay), in TU
-	 * MaxChannelTime: (>= MinChannelTime), in TU
-	 */
+	if (local->ops->hw_scan)
+		__set_bit(SCAN_HW_SCANNING, &local->scanning);
+	else
+		__set_bit(SCAN_SW_SCANNING, &local->scanning);
 
-	 /* MLME-SCAN.confirm
-	  * BSSDescriptionSet
-	  * ResultCode: SUCCESS, INVALID_PARAMETERS
+	/*
+	 * Kicking off the scan need not be protected,
+	 * only the scan variable stuff, since now
+	 * local->scan_req is assigned and other callers
+	 * will abort their scan attempts.
+	 *
+	 * This avoids too many locking dependencies
+	 * so that the scan completed calls have more
+	 * locking freedom.
 	 */
 
-	if (local->sw_scanning || local->hw_scanning) {
-		if (local->scan_sdata == scan_sdata)
-			return 0;
-		return -EBUSY;
-	}
+	ieee80211_recalc_idle(local);
+	mutex_unlock(&local->scan_mtx);
 
 	if (local->ops->hw_scan) {
-		int rc;
+		WARN_ON(!ieee80211_prep_hw_scan(local));
+		rc = drv_hw_scan(local, local->hw_scan_req);
+	} else
+		rc = ieee80211_start_sw_scan(local);
 
-		local->hw_scanning = true;
-		rc = local->ops->hw_scan(local_to_hw(local), req);
-		if (rc) {
-			local->hw_scanning = false;
-			return rc;
-		}
-		local->scan_sdata = scan_sdata;
-		return 0;
+	mutex_lock(&local->scan_mtx);
+
+	if (rc) {
+		kfree(local->hw_scan_req);
+		local->hw_scan_req = NULL;
+		local->scanning = 0;
+
+		ieee80211_recalc_idle(local);
+
+		local->scan_req = NULL;
+		local->scan_sdata = NULL;
 	}
 
-	local->sw_scanning = true;
+	return rc;
+}
+
+static int ieee80211_scan_state_decision(struct ieee80211_local *local,
+					 unsigned long *next_delay)
+{
+	bool associated = false;
+	struct ieee80211_sub_if_data *sdata;
+
+	/* if no more bands/channels left, complete scan and advance to the idle state */
+	if (local->scan_channel_idx >= local->scan_req->n_channels) {
+		ieee80211_scan_completed(&local->hw, false);
+		return 1;
+	}
 
+	/* check if at least one STA interface is associated */
 	mutex_lock(&local->iflist_mtx);
 	list_for_each_entry(sdata, &local->interfaces, list) {
-		if (!netif_running(sdata->dev))
+		if (!ieee80211_sdata_running(sdata))
 			continue;
 
-		/* disable beaconing */
-		if (sdata->vif.type == NL80211_IFTYPE_AP ||
-		    sdata->vif.type == NL80211_IFTYPE_ADHOC ||
-		    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
-			ieee80211_if_config(sdata,
-					    IEEE80211_IFCC_BEACON_ENABLED);
-
 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
-			if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) {
-				netif_tx_stop_all_queues(sdata->dev);
-				ieee80211_send_nullfunc(local, sdata, 1);
+			if (sdata->u.mgd.associated) {
+				associated = true;
+				break;
 			}
-		} else
-			netif_tx_stop_all_queues(sdata->dev);
+		}
 	}
 	mutex_unlock(&local->iflist_mtx);
 
-	local->scan_state = SCAN_SET_CHANNEL;
-	local->scan_channel_idx = 0;
-	local->scan_sdata = scan_sdata;
-	local->scan_req = req;
+	if (local->scan_channel) {
+		/*
+		 * we're currently scanning a different channel, let's
+		 * switch back to the operating channel now if at least
+		 * one interface is associated. Otherwise just scan the
+		 * next channel
+		 */
+		if (associated)
+			local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
+		else
+			local->next_scan_state = SCAN_SET_CHANNEL;
+	} else {
+		/*
+		 * we're on the operating channel currently, let's
+		 * leave that channel now to scan another one
+		 */
+		local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
+	}
 
-	netif_addr_lock_bh(local->mdev);
-	local->filter_flags |= FIF_BCN_PRBRESP_PROMISC;
-	local->ops->configure_filter(local_to_hw(local),
-				     FIF_BCN_PRBRESP_PROMISC,
-				     &local->filter_flags,
-				     local->mdev->mc_count,
-				     local->mdev->mc_list);
-	netif_addr_unlock_bh(local->mdev);
+	*next_delay = 0;
+	return 0;
+}
 
-	/* TODO: start scan as soon as all nullfunc frames are ACKed */
-	queue_delayed_work(local->hw.workqueue, &local->scan_work,
-			   IEEE80211_CHANNEL_TIME);
+static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
+						    unsigned long *next_delay)
+{
+	ieee80211_offchannel_stop_station(local);
 
-	return 0;
+	__set_bit(SCAN_OFF_CHANNEL, &local->scanning);
+
+	/*
+	 * What if the nullfunc frames didn't arrive?
+	 */
+	drv_flush(local, false);
+	if (local->ops->flush)
+		*next_delay = 0;
+	else
+		*next_delay = HZ / 10;
+
+	/* advance to the next channel to be scanned */
+	local->next_scan_state = SCAN_SET_CHANNEL;
 }
 
+static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
+						    unsigned long *next_delay)
+{
+	/* switch back to the operating channel */
+	local->scan_channel = NULL;
+	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 
-int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
-			   struct cfg80211_scan_request *req)
+	/*
+	 * Only re-enable station mode interface now; beaconing will be
+	 * re-enabled once the full scan has been completed.
+	 */
+	ieee80211_offchannel_return(local, false);
+
+	__clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
+
+	*next_delay = HZ / 5;
+	local->next_scan_state = SCAN_DECISION;
+}
+
+static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
+					     unsigned long *next_delay)
 {
-	struct ieee80211_local *local = sdata->local;
-	struct ieee80211_if_sta *ifsta;
+	int skip;
+	struct ieee80211_channel *chan;
 
-	if (!req)
-		return -EINVAL;
+	skip = 0;
+	chan = local->scan_req->channels[local->scan_channel_idx];
 
-	if (local->scan_req && local->scan_req != req)
-		return -EBUSY;
+	local->scan_channel = chan;
+	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
+		skip = 1;
 
-	local->scan_req = req;
+	/* advance state machine to next channel/band */
+	local->scan_channel_idx++;
 
-	if (sdata->vif.type != NL80211_IFTYPE_STATION)
-		return ieee80211_start_scan(sdata, req);
+	if (skip) {
+		/* if we skip this channel return to the decision state */
+		local->next_scan_state = SCAN_DECISION;
+		return;
+	}
 
 	/*
-	 * STA has a state machine that might need to defer scanning
-	 * while it's trying to associate/authenticate, therefore we
-	 * queue it up to the state machine in that case.
+	 * 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.
 	 */
+	if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
+	    !local->scan_req->n_ssids) {
+		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
+		local->next_scan_state = SCAN_DECISION;
+		return;
+	}
 
-	if (local->sw_scanning || local->hw_scanning) {
-		if (local->scan_sdata == sdata)
-			return 0;
-		return -EBUSY;
+	/* active scan, send probes */
+	*next_delay = IEEE80211_PROBE_DELAY;
+	local->next_scan_state = SCAN_SEND_PROBE;
+}
+
+static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
+					    unsigned long *next_delay)
+{
+	int i;
+	struct ieee80211_sub_if_data *sdata = local->scan_sdata;
+
+	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);
+
+	/*
+	 * After sending probe requests, wait for probe responses
+	 * on the channel.
+	 */
+	*next_delay = IEEE80211_CHANNEL_TIME;
+	local->next_scan_state = SCAN_DECISION;
+}
+
+void ieee80211_scan_work(struct work_struct *work)
+{
+	struct ieee80211_local *local =
+		container_of(work, struct ieee80211_local, scan_work.work);
+	struct ieee80211_sub_if_data *sdata = local->scan_sdata;
+	unsigned long next_delay = 0;
+
+	mutex_lock(&local->scan_mtx);
+	if (!sdata || !local->scan_req) {
+		mutex_unlock(&local->scan_mtx);
+		return;
 	}
 
-	ifsta = &sdata->u.sta;
-	set_bit(IEEE80211_STA_REQ_SCAN, &ifsta->request);
-	queue_work(local->hw.workqueue, &ifsta->work);
+	if (local->hw_scan_req) {
+		int rc = drv_hw_scan(local, local->hw_scan_req);
+		mutex_unlock(&local->scan_mtx);
+		if (rc)
+			ieee80211_scan_completed(&local->hw, true);
+		return;
+	}
 
-	return 0;
+	if (local->scan_req && !local->scanning) {
+		struct cfg80211_scan_request *req = local->scan_req;
+		int rc;
+
+		local->scan_req = NULL;
+		local->scan_sdata = NULL;
+
+		rc = __ieee80211_start_scan(sdata, req);
+		mutex_unlock(&local->scan_mtx);
+
+		if (rc)
+			ieee80211_scan_completed(&local->hw, true);
+		return;
+	}
+
+	mutex_unlock(&local->scan_mtx);
+
+	/*
+	 * Avoid re-scheduling when the sdata is going away.
+	 */
+	if (!ieee80211_sdata_running(sdata)) {
+		ieee80211_scan_completed(&local->hw, true);
+		return;
+	}
+
+	/*
+	 * as long as no delay is required advance immediately
+	 * without scheduling a new work
+	 */
+	do {
+		switch (local->next_scan_state) {
+		case SCAN_DECISION:
+			if (ieee80211_scan_state_decision(local, &next_delay))
+				return;
+			break;
+		case SCAN_SET_CHANNEL:
+			ieee80211_scan_state_set_channel(local, &next_delay);
+			break;
+		case SCAN_SEND_PROBE:
+			ieee80211_scan_state_send_probe(local, &next_delay);
+			break;
+		case SCAN_LEAVE_OPER_CHANNEL:
+			ieee80211_scan_state_leave_oper_channel(local, &next_delay);
+			break;
+		case SCAN_ENTER_OPER_CHANNEL:
+			ieee80211_scan_state_enter_oper_channel(local, &next_delay);
+			break;
+		}
+	} while (next_delay == 0);
+
+	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
+}
+
+int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
+			   struct cfg80211_scan_request *req)
+{
+	int res;
+
+	mutex_lock(&sdata->local->scan_mtx);
+	res = __ieee80211_start_scan(sdata, req);
+	mutex_unlock(&sdata->local->scan_mtx);
+
+	return res;
+}
+
+int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
+				    const u8 *ssid, u8 ssid_len)
+{
+	struct ieee80211_local *local = sdata->local;
+	int ret = -EBUSY;
+
+	mutex_lock(&local->scan_mtx);
+
+	/* busy scanning */
+	if (local->scan_req)
+		goto unlock;
+
+	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
+	local->int_scan_req->ssids[0].ssid_len = ssid_len;
+
+	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
+ unlock:
+	mutex_unlock(&local->scan_mtx);
+	return ret;
+}
+
+void ieee80211_scan_cancel(struct ieee80211_local *local)
+{
+	bool abortscan;
+
+	cancel_delayed_work_sync(&local->scan_work);
+
+	/*
+	 * Only call this function when a scan can't be
+	 * queued -- mostly at suspend under RTNL.
+	 */
+	mutex_lock(&local->scan_mtx);
+	abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
+		    (!local->scanning && local->scan_req);
+	mutex_unlock(&local->scan_mtx);
+
+	if (abortscan)
+		ieee80211_scan_completed(&local->hw, true);
 }