mac80211: wait for beacon before enabling powersave
[linux-2.6.git] / net / mac80211 / scan.c
index 68fa782..bc061f6 100644 (file)
@@ -1,5 +1,6 @@
 /*
- * BSS client mode implementation
+ * Scanning implementation
+ *
  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
  * Copyright 2004, Instant802 Networks, Inc.
  * Copyright 2005, Devicescape Software, Inc.
  * published by the Free Software Foundation.
  */
 
-#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)
+{
+       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_send_nullfunc(struct ieee80211_local *local,
-                                   struct ieee80211_sub_if_data *sdata,
-                                   int powersave)
+static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
 {
-       struct sk_buff *skb;
-       struct ieee80211_hdr *nullfunc;
-       __le16 fc;
+       struct ieee80211_bss *bss = (void *)cbss->priv;
 
-       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);
+       kfree(bss_mesh_id(bss));
+       kfree(bss_mesh_cfg(bss));
+}
+
+void ieee80211_rx_bss_put(struct ieee80211_local *local,
+                         struct ieee80211_bss *bss)
+{
+       if (!bss)
                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_sta_tx(sdata, skb, 0);
+       cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
 }
 
-static void ieee80211_restart_sta_timer(struct ieee80211_sub_if_data *sdata)
+static bool is_uapsd_supported(struct ieee802_11_elems *elems)
 {
-       if (sdata->vif.type == IEEE80211_IF_TYPE_STA ||
-           ieee80211_vif_is_mesh(&sdata->vif))
-               ieee80211_sta_timer((unsigned long)sdata);
+       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;
 }
 
-void ieee80211_scan_completed(struct ieee80211_hw *hw)
+struct ieee80211_bss *
+ieee80211_bss_info_update(struct ieee80211_local *local,
+                         struct ieee80211_rx_status *rx_status,
+                         struct ieee80211_mgmt *mgmt,
+                         size_t len,
+                         struct ieee802_11_elems *elems,
+                         struct ieee80211_channel *channel,
+                         bool beacon)
 {
-       struct ieee80211_local *local = hw_to_local(hw);
-       struct ieee80211_sub_if_data *sdata;
-       union iwreq_data wrqu;
-
-       local->last_scan_completed = jiffies;
-       memset(&wrqu, 0, sizeof(wrqu));
-       wireless_send_event(local->scan_sdata->dev, SIOCGIWSCAN, &wrqu, NULL);
-
-       if (local->sta_hw_scanning) {
-               local->sta_hw_scanning = 0;
-               if (ieee80211_hw_config(local))
-                       printk(KERN_DEBUG "%s: failed to restore operational "
-                              "channel after scan\n", wiphy_name(local->hw.wiphy));
-               /* Restart STA timer for HW scan case */
-               rcu_read_lock();
-               list_for_each_entry_rcu(sdata, &local->interfaces, list)
-                       ieee80211_restart_sta_timer(sdata);
-               rcu_read_unlock();
+       struct cfg80211_bss *cbss;
+       struct ieee80211_bss *bss;
+       int clen;
+       s32 signal = 0;
 
-               goto done;
+       if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
+               signal = rx_status->signal * 100;
+       else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
+               signal = (rx_status->signal * 100) / local->hw.max_signal;
+
+       cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
+                                        mgmt, len, signal, GFP_ATOMIC);
+
+       if (!cbss)
+               return NULL;
+
+       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) {
+               bss->erp_value = elems->erp_info[0];
+               bss->has_erp_value = 1;
        }
 
-       local->sta_sw_scanning = 0;
-       if (ieee80211_hw_config(local))
-               printk(KERN_DEBUG "%s: failed to restore operational "
-                      "channel after scan\n", wiphy_name(local->hw.wiphy));
-
-
-       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);
-
-       rcu_read_lock();
-       list_for_each_entry_rcu(sdata, &local->interfaces, list) {
-               /* Tell AP we're back */
-               if (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
-                       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);
+       if (elems->tim) {
+               struct ieee80211_tim_ie *tim_ie =
+                       (struct ieee80211_tim_ie *)elems->tim;
+               bss->dtim_period = tim_ie->dtim_period;
+       }
 
-               ieee80211_restart_sta_timer(sdata);
+       bss->supp_rates_len = 0;
+       if (elems->supp_rates) {
+               clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
+               if (clen > elems->supp_rates_len)
+                       clen = elems->supp_rates_len;
+               memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates,
+                      clen);
+               bss->supp_rates_len += clen;
+       }
+       if (elems->ext_supp_rates) {
+               clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
+               if (clen > elems->ext_supp_rates_len)
+                       clen = elems->ext_supp_rates_len;
+               memcpy(&bss->supp_rates[bss->supp_rates_len],
+                      elems->ext_supp_rates, clen);
+               bss->supp_rates_len += clen;
        }
-       rcu_read_unlock();
 
- done:
-       ieee80211_mlme_notify_scan_completed(local);
-}
-EXPORT_SYMBOL(ieee80211_scan_completed);
+       bss->wmm_used = elems->wmm_param || elems->wmm_info;
+       bss->uapsd_supported = is_uapsd_supported(elems);
 
+       if (!beacon)
+               bss->last_probe_resp = jiffies;
 
-void ieee80211_sta_scan_work(struct work_struct *work)
+       return bss;
+}
+
+ieee80211_rx_result
+ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 {
-       struct ieee80211_local *local =
-               container_of(work, struct ieee80211_local, scan_work.work);
-       struct ieee80211_sub_if_data *sdata = local->scan_sdata;
-       struct ieee80211_supported_band *sband;
-       struct ieee80211_channel *chan;
-       int skip;
-       unsigned long next_delay = 0;
+       struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
+       struct ieee80211_mgmt *mgmt;
+       struct ieee80211_bss *bss;
+       u8 *elements;
+       struct ieee80211_channel *channel;
+       size_t baselen;
+       int freq;
+       __le16 fc;
+       bool presp, beacon = false;
+       struct ieee802_11_elems elems;
 
-       if (!local->sta_sw_scanning)
-               return;
+       if (skb->len < 2)
+               return RX_DROP_UNUSABLE;
 
-       switch (local->scan_state) {
-       case SCAN_SET_CHANNEL:
-               /*
-                * Get current scan band. scan_band may be IEEE80211_NUM_BANDS
-                * after we successfully scanned the last channel of the last
-                * band (and the last band is supported by the hw)
-                */
-               if (local->scan_band < IEEE80211_NUM_BANDS)
-                       sband = local->hw.wiphy->bands[local->scan_band];
-               else
-                       sband = NULL;
+       mgmt = (struct ieee80211_mgmt *) skb->data;
+       fc = mgmt->frame_control;
 
-               /*
-                * If we are at an unsupported band and have more bands
-                * left to scan, advance to the next supported one.
-                */
-               while (!sband && local->scan_band < IEEE80211_NUM_BANDS - 1) {
-                       local->scan_band++;
-                       sband = local->hw.wiphy->bands[local->scan_band];
-                       local->scan_channel_idx = 0;
-               }
+       if (ieee80211_is_ctl(fc))
+               return RX_CONTINUE;
 
-               /* if no more bands/channels left, complete scan */
-               if (!sband || local->scan_channel_idx >= sband->n_channels) {
-                       ieee80211_scan_completed(local_to_hw(local));
-                       return;
-               }
-               skip = 0;
-               chan = &sband->channels[local->scan_channel_idx];
-
-               if (chan->flags & IEEE80211_CHAN_DISABLED ||
-                   (sdata->vif.type == IEEE80211_IF_TYPE_IBSS &&
-                    chan->flags & IEEE80211_CHAN_NO_IBSS))
-                       skip = 1;
-
-               if (!skip) {
-                       local->scan_channel = chan;
-                       if (ieee80211_hw_config(local)) {
-                               printk(KERN_DEBUG "%s: failed to set freq to "
-                                      "%d MHz for scan\n", wiphy_name(local->hw.wiphy),
-                                      chan->center_freq);
-                               skip = 1;
-                       }
-               }
+       if (skb->len < 24)
+               return RX_DROP_MONITOR;
 
-               /* advance state machine to next channel/band */
-               local->scan_channel_idx++;
-               if (local->scan_channel_idx >= sband->n_channels) {
-                       /*
-                        * scan_band may end up == IEEE80211_NUM_BANDS, but
-                        * we'll catch that case above and complete the scan
-                        * if that is the case.
-                        */
-                       local->scan_band++;
-                       local->scan_channel_idx = 0;
-               }
+       presp = ieee80211_is_probe_resp(fc);
+       if (presp) {
+               /* ignore ProbeResp to foreign address */
+               if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
+                       return RX_DROP_MONITOR;
 
-               if (skip)
-                       break;
+               presp = true;
+               elements = mgmt->u.probe_resp.variable;
+               baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
+       } else {
+               beacon = ieee80211_is_beacon(fc);
+               baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
+               elements = mgmt->u.beacon.variable;
+       }
 
-               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;
+       if (!presp && !beacon)
+               return RX_CONTINUE;
 
-               if (local->scan_channel->flags & IEEE80211_CHAN_PASSIVE_SCAN)
-                       break;
-               ieee80211_send_probe_req(sdata, NULL, local->scan_ssid,
-                                        local->scan_ssid_len);
-               next_delay = IEEE80211_CHANNEL_TIME;
-               break;
-       }
+       if (baselen > skb->len)
+               return RX_DROP_MONITOR;
+
+       ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
+
+       if (elems.ds_params && elems.ds_params_len == 1)
+               freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
+       else
+               freq = rx_status->freq;
+
+       channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
 
-       if (local->sta_sw_scanning)
-               queue_delayed_work(local->hw.workqueue, &local->scan_work,
-                                  next_delay);
+       if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
+               return RX_DROP_MONITOR;
+
+       bss = ieee80211_bss_info_update(sdata->local, rx_status,
+                                       mgmt, skb->len, &elems,
+                                       channel, beacon);
+       if (bss)
+               ieee80211_rx_bss_put(sdata->local, bss);
+
+       dev_kfree_skb(skb);
+       return RX_QUEUED;
 }
 
+/* return false if no more work */
+static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
+{
+       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++;
+                       }
+               }
+
+               local->hw_scan_band++;
+       } while (!n_chans);
+
+       local->hw_scan_req->n_channels = n_chans;
 
-int ieee80211_sta_start_scan(struct ieee80211_sub_if_data *scan_sdata,
-                            u8 *ssid, size_t ssid_len)
+       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 = scan_sdata->local;
-       struct ieee80211_sub_if_data *sdata;
+       struct ieee80211_local *local = hw_to_local(hw);
+       bool was_hw_scan;
 
-       if (ssid_len > IEEE80211_MAX_SSID_LEN)
-               return -EINVAL;
-
-       /* 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
-        */
+       mutex_lock(&local->scan_mtx);
 
-        /* MLME-SCAN.confirm
-         * BSSDescriptionSet
-         * ResultCode: SUCCESS, INVALID_PARAMETERS
+       /*
+        * 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 (local->sta_sw_scanning || local->sta_hw_scanning) {
-               if (local->scan_sdata == scan_sdata)
-                       return 0;
-               return -EBUSY;
+       if (WARN_ON(!local->scan_req)) {
+               mutex_unlock(&local->scan_mtx);
+               return;
        }
 
-       if (local->ops->hw_scan) {
-               int rc = local->ops->hw_scan(local_to_hw(local),
-                                            ssid, ssid_len);
-               if (!rc) {
-                       local->sta_hw_scanning = 1;
-                       local->scan_sdata = scan_sdata;
-               }
-               return rc;
+       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;
        }
 
-       local->sta_sw_scanning = 1;
+       kfree(local->hw_scan_req);
+       local->hw_scan_req = NULL;
 
-       rcu_read_lock();
-       list_for_each_entry_rcu(sdata, &local->interfaces, list) {
-               if (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
-                       if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) {
-                               netif_tx_stop_all_queues(sdata->dev);
-                               ieee80211_send_nullfunc(local, sdata, 1);
-                       }
-               } else
-                       netif_tx_stop_all_queues(sdata->dev);
-       }
-       rcu_read_unlock();
+       if (local->scan_req != local->int_scan_req)
+               cfg80211_scan_done(local->scan_req, aborted);
+       local->scan_req = NULL;
+       local->scan_sdata = NULL;
 
-       if (ssid) {
-               local->scan_ssid_len = ssid_len;
-               memcpy(local->scan_ssid, ssid, ssid_len);
-       } else
-               local->scan_ssid_len = 0;
-       local->scan_state = SCAN_SET_CHANNEL;
+       local->scanning = 0;
+       local->scan_channel = NULL;
+
+       /* we only have to protect scan_req and hw/sw scan */
+       mutex_unlock(&local->scan_mtx);
+
+       ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+       if (was_hw_scan)
+               goto done;
+
+       ieee80211_configure_filter(local);
+
+       drv_sw_scan_complete(local);
+
+       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);
+
+static int ieee80211_start_sw_scan(struct ieee80211_local *local)
+{
+       /*
+        * 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().
+        */
+       drv_sw_scan_start(local);
+
+       ieee80211_offchannel_stop_beaconing(local);
+
+       local->next_scan_state = SCAN_DECISION;
        local->scan_channel_idx = 0;
-       local->scan_band = IEEE80211_BAND_2GHZ;
-       local->scan_sdata = scan_sdata;
-
-       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);
-
-       /* TODO: start scan as soon as all nullfunc frames are ACKed */
-       queue_delayed_work(local->hw.workqueue, &local->scan_work,
-                          IEEE80211_CHANNEL_TIME);
+
+       drv_flush(local, false);
+
+       ieee80211_configure_filter(local);
+
+       ieee80211_queue_delayed_work(&local->hw,
+                                    &local->scan_work,
+                                    IEEE80211_CHANNEL_TIME);
 
        return 0;
 }
 
 
-int ieee80211_sta_req_scan(struct ieee80211_sub_if_data *sdata, u8 *ssid, size_t ssid_len)
+static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
+                                 struct cfg80211_scan_request *req)
 {
-       struct ieee80211_if_sta *ifsta = &sdata->u.sta;
        struct ieee80211_local *local = sdata->local;
+       int rc;
 
-       if (sdata->vif.type != IEEE80211_IF_TYPE_STA)
-               return ieee80211_sta_start_scan(sdata, ssid, ssid_len);
-
-       if (local->sta_sw_scanning || local->sta_hw_scanning) {
-               if (local->scan_sdata == sdata)
-                       return 0;
+       if (local->scan_req)
                return -EBUSY;
+
+       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;
        }
 
-       ifsta->scan_ssid_len = ssid_len;
-       if (ssid_len)
-               memcpy(ifsta->scan_ssid, ssid, ssid_len);
-       set_bit(IEEE80211_STA_REQ_SCAN, &ifsta->request);
-       queue_work(local->hw.workqueue, &ifsta->work);
-       return 0;
+       local->scan_req = req;
+       local->scan_sdata = sdata;
+
+       if (!list_empty(&local->work_list)) {
+               /* wait for the work to finish/time out */
+               return 0;
+       }
+
+       if (local->ops->hw_scan)
+               __set_bit(SCAN_HW_SCANNING, &local->scanning);
+       else
+               __set_bit(SCAN_SW_SCANNING, &local->scanning);
+       /*
+        * 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 getting a scan_mtx -> iflist_mtx
+        * dependency, so that the scan completed calls
+        * have more locking freedom.
+        */
+
+       ieee80211_recalc_idle(local);
+       mutex_unlock(&local->scan_mtx);
+
+       if (local->ops->hw_scan) {
+               WARN_ON(!ieee80211_prep_hw_scan(local));
+               rc = drv_hw_scan(local, local->hw_scan_req);
+       } else
+               rc = ieee80211_start_sw_scan(local);
+
+       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;
+       }
+
+       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 (!ieee80211_sdata_running(sdata))
+                       continue;
+
+               if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+                       if (sdata->u.mgd.associated) {
+                               associated = true;
+                               break;
+                       }
+               }
+       }
+       mutex_unlock(&local->iflist_mtx);
+
+       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;
+       }
 
-static void ieee80211_sta_add_scan_ies(struct iw_request_info *info,
-                                      struct ieee80211_sta_bss *bss,
-                                      char **current_ev, char *end_buf)
+       *next_delay = 0;
+       return 0;
+}
+
+static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
+                                                   unsigned long *next_delay)
 {
-       u8 *pos, *end, *next;
-       struct iw_event iwe;
+       ieee80211_offchannel_stop_station(local);
 
-       if (bss == NULL || bss->ies == NULL)
-               return;
+       __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
 
        /*
-        * If needed, fragment the IEs buffer (at IE boundaries) into short
-        * enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
+        * What if the nullfunc frames didn't arrive?
         */
-       pos = bss->ies;
-       end = pos + bss->ies_len;
+       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);
+
+       /*
+        * 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);
 
-       while (end - pos > IW_GENERIC_IE_MAX) {
-               next = pos + 2 + pos[1];
-               while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
-                       next = next + 2 + next[1];
+       *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)
+{
+       int skip;
+       struct ieee80211_channel *chan;
+
+       skip = 0;
+       chan = local->scan_req->channels[local->scan_channel_idx];
+
+       local->scan_channel = chan;
+       if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
+               skip = 1;
 
-               memset(&iwe, 0, sizeof(iwe));
-               iwe.cmd = IWEVGENIE;
-               iwe.u.data.length = next - pos;
-               *current_ev = iwe_stream_add_point(info, *current_ev,
-                                                  end_buf, &iwe, pos);
+       /* advance state machine to next channel/band */
+       local->scan_channel_idx++;
 
-               pos = next;
+       if (skip) {
+               /* if we skip this channel return to the decision state */
+               local->next_scan_state = SCAN_DECISION;
+               return;
        }
 
-       if (end > pos) {
-               memset(&iwe, 0, sizeof(iwe));
-               iwe.cmd = IWEVGENIE;
-               iwe.u.data.length = end - pos;
-               *current_ev = iwe_stream_add_point(info, *current_ev,
-                                                  end_buf, &iwe, pos);
+       /*
+        * 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;
        }
+
+       /* 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);
 
-static char *
-ieee80211_sta_scan_result(struct ieee80211_local *local,
-                         struct iw_request_info *info,
-                         struct ieee80211_sta_bss *bss,
-                         char *current_ev, char *end_buf)
+       /*
+        * 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 iw_event iwe;
-       char *buf;
-
-       if (time_after(jiffies,
-                      bss->last_update + IEEE80211_SCAN_RESULT_EXPIRE))
-               return current_ev;
-
-       memset(&iwe, 0, sizeof(iwe));
-       iwe.cmd = SIOCGIWAP;
-       iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
-       memcpy(iwe.u.ap_addr.sa_data, bss->bssid, ETH_ALEN);
-       current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
-                                         IW_EV_ADDR_LEN);
-
-       memset(&iwe, 0, sizeof(iwe));
-       iwe.cmd = SIOCGIWESSID;
-       if (bss_mesh_cfg(bss)) {
-               iwe.u.data.length = bss_mesh_id_len(bss);
-               iwe.u.data.flags = 1;
-               current_ev = iwe_stream_add_point(info, current_ev, end_buf,
-                                                 &iwe, bss_mesh_id(bss));
-       } else {
-               iwe.u.data.length = bss->ssid_len;
-               iwe.u.data.flags = 1;
-               current_ev = iwe_stream_add_point(info, current_ev, end_buf,
-                                                 &iwe, bss->ssid);
+       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;
        }
 
-       if (bss->capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS)
-           || bss_mesh_cfg(bss)) {
-               memset(&iwe, 0, sizeof(iwe));
-               iwe.cmd = SIOCGIWMODE;
-               if (bss_mesh_cfg(bss))
-                       iwe.u.mode = IW_MODE_MESH;
-               else if (bss->capability & WLAN_CAPABILITY_ESS)
-                       iwe.u.mode = IW_MODE_MASTER;
-               else
-                       iwe.u.mode = IW_MODE_ADHOC;
-               current_ev = iwe_stream_add_event(info, current_ev, end_buf,
-                                                 &iwe, IW_EV_UINT_LEN);
+       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;
        }
 
-       memset(&iwe, 0, sizeof(iwe));
-       iwe.cmd = SIOCGIWFREQ;
-       iwe.u.freq.m = ieee80211_frequency_to_channel(bss->freq);
-       iwe.u.freq.e = 0;
-       current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
-                                         IW_EV_FREQ_LEN);
-
-       memset(&iwe, 0, sizeof(iwe));
-       iwe.cmd = SIOCGIWFREQ;
-       iwe.u.freq.m = bss->freq;
-       iwe.u.freq.e = 6;
-       current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
-                                         IW_EV_FREQ_LEN);
-       memset(&iwe, 0, sizeof(iwe));
-       iwe.cmd = IWEVQUAL;
-       iwe.u.qual.qual = bss->qual;
-       iwe.u.qual.level = bss->signal;
-       iwe.u.qual.noise = bss->noise;
-       iwe.u.qual.updated = local->wstats_flags;
-       current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
-                                         IW_EV_QUAL_LEN);
-
-       memset(&iwe, 0, sizeof(iwe));
-       iwe.cmd = SIOCGIWENCODE;
-       if (bss->capability & WLAN_CAPABILITY_PRIVACY)
-               iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
-       else
-               iwe.u.data.flags = IW_ENCODE_DISABLED;
-       iwe.u.data.length = 0;
-       current_ev = iwe_stream_add_point(info, current_ev, end_buf,
-                                         &iwe, "");
-
-       ieee80211_sta_add_scan_ies(info, bss, &current_ev, end_buf);
-
-       if (bss->supp_rates_len > 0) {
-               /* display all supported rates in readable format */
-               char *p = current_ev + iwe_stream_lcp_len(info);
-               int i;
-
-               memset(&iwe, 0, sizeof(iwe));
-               iwe.cmd = SIOCGIWRATE;
-               /* Those two flags are ignored... */
-               iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;
-
-               for (i = 0; i < bss->supp_rates_len; i++) {
-                       iwe.u.bitrate.value = ((bss->supp_rates[i] &
-                                                       0x7f) * 500000);
-                       p = iwe_stream_add_value(info, current_ev, p,
-                                       end_buf, &iwe, IW_EV_PARAM_LEN);
-               }
-               current_ev = p;
+       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;
        }
 
-       buf = kmalloc(30, GFP_ATOMIC);
-       if (buf) {
-               memset(&iwe, 0, sizeof(iwe));
-               iwe.cmd = IWEVCUSTOM;
-               sprintf(buf, "tsf=%016llx", (unsigned long long)(bss->timestamp));
-               iwe.u.data.length = strlen(buf);
-               current_ev = iwe_stream_add_point(info, current_ev, end_buf,
-                                                 &iwe, buf);
-               memset(&iwe, 0, sizeof(iwe));
-               iwe.cmd = IWEVCUSTOM;
-               sprintf(buf, " Last beacon: %dms ago",
-                       jiffies_to_msecs(jiffies - bss->last_update));
-               iwe.u.data.length = strlen(buf);
-               current_ev = iwe_stream_add_point(info, current_ev,
-                                                 end_buf, &iwe, buf);
-               kfree(buf);
+       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;
        }
 
-       if (bss_mesh_cfg(bss)) {
-               u8 *cfg = bss_mesh_cfg(bss);
-               buf = kmalloc(50, GFP_ATOMIC);
-               if (buf) {
-                       memset(&iwe, 0, sizeof(iwe));
-                       iwe.cmd = IWEVCUSTOM;
-                       sprintf(buf, "Mesh network (version %d)", cfg[0]);
-                       iwe.u.data.length = strlen(buf);
-                       current_ev = iwe_stream_add_point(info, current_ev,
-                                                         end_buf,
-                                                         &iwe, buf);
-                       sprintf(buf, "Path Selection Protocol ID: "
-                               "0x%02X%02X%02X%02X", cfg[1], cfg[2], cfg[3],
-                                                       cfg[4]);
-                       iwe.u.data.length = strlen(buf);
-                       current_ev = iwe_stream_add_point(info, current_ev,
-                                                         end_buf,
-                                                         &iwe, buf);
-                       sprintf(buf, "Path Selection Metric ID: "
-                               "0x%02X%02X%02X%02X", cfg[5], cfg[6], cfg[7],
-                                                       cfg[8]);
-                       iwe.u.data.length = strlen(buf);
-                       current_ev = iwe_stream_add_point(info, current_ev,
-                                                         end_buf,
-                                                         &iwe, buf);
-                       sprintf(buf, "Congestion Control Mode ID: "
-                               "0x%02X%02X%02X%02X", cfg[9], cfg[10],
-                                                       cfg[11], cfg[12]);
-                       iwe.u.data.length = strlen(buf);
-                       current_ev = iwe_stream_add_point(info, current_ev,
-                                                         end_buf,
-                                                         &iwe, buf);
-                       sprintf(buf, "Channel Precedence: "
-                               "0x%02X%02X%02X%02X", cfg[13], cfg[14],
-                                                       cfg[15], cfg[16]);
-                       iwe.u.data.length = strlen(buf);
-                       current_ev = iwe_stream_add_point(info, current_ev,
-                                                         end_buf,
-                                                         &iwe, buf);
-                       kfree(buf);
+       /*
+        * 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);
 
-       return current_ev;
+       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_sta_scan_results(struct ieee80211_local *local,
-                              struct iw_request_info *info,
-                              char *buf, size_t len)
+int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
+                                   const u8 *ssid, u8 ssid_len)
 {
-       char *current_ev = buf;
-       char *end_buf = buf + len;
-       struct ieee80211_sta_bss *bss;
-
-       spin_lock_bh(&local->sta_bss_lock);
-       list_for_each_entry(bss, &local->sta_bss_list, list) {
-               if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
-                       spin_unlock_bh(&local->sta_bss_lock);
-                       return -E2BIG;
-               }
-               current_ev = ieee80211_sta_scan_result(local, info, bss,
-                                                      current_ev, end_buf);
-       }
-       spin_unlock_bh(&local->sta_bss_lock);
-       return current_ev - buf;
+       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);
 }