+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))
+ 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;
+ }
+
+ *next_delay = 0;
+ return 0;
+}
+
+static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
+ unsigned long *next_delay)
+{
+ struct ieee80211_sub_if_data *sdata;
+
+ /*
+ * notify the AP about us leaving the channel and stop all STA interfaces
+ */
+ mutex_lock(&local->iflist_mtx);
+ list_for_each_entry(sdata, &local->interfaces, list) {
+ if (!netif_running(sdata->dev))
+ continue;
+
+ if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+ netif_tx_stop_all_queues(sdata->dev);
+ if (sdata->u.mgd.associated)
+ ieee80211_scan_ps_enable(sdata);
+ }
+ }
+ mutex_unlock(&local->iflist_mtx);
+
+ __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
+
+ /* advance to the next channel to be scanned */
+ *next_delay = HZ / 10;
+ local->next_scan_state = SCAN_SET_CHANNEL;
+}
+
+static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
+ unsigned long *next_delay)
+{
+ struct ieee80211_sub_if_data *sdata = local->scan_sdata;
+
+ /* switch back to the operating channel */
+ local->scan_channel = NULL;
+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+
+ /*
+ * notify the AP about us being back and restart all STA interfaces
+ */
+ mutex_lock(&local->iflist_mtx);
+ list_for_each_entry(sdata, &local->interfaces, list) {
+ if (!netif_running(sdata->dev))
+ continue;
+
+ /* Tell AP we're back */
+ if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+ if (sdata->u.mgd.associated)
+ ieee80211_scan_ps_disable(sdata);
+ netif_tx_wake_all_queues(sdata->dev);
+ }
+ }
+ mutex_unlock(&local->iflist_mtx);
+
+ __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)
+{
+ int skip;
+ struct ieee80211_channel *chan;
+ struct ieee80211_sub_if_data *sdata = local->scan_sdata;
+
+ 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;
+ }
+
+ /* advance state machine to next channel/band */
+ local->scan_channel_idx++;
+
+ if (skip) {
+ /* if we skip this channel return to the decision state */
+ local->next_scan_state = SCAN_DECISION;
+ return;
+ }
+
+ /*
+ * 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);
+
+ /*
+ * After sending probe requests, wait for probe responses
+ * on the channel.
+ */
+ *next_delay = IEEE80211_CHANNEL_TIME;
+ local->next_scan_state = SCAN_DECISION;
+}
+