mac80211: Generalize off-channel operation helpers from scan code

The off-channel operations for going into power save mode (station
mode) or stop beaconing (AP/IBSS) are not limited to scanning. Move
these into a separate file and allow them to be used for other
purposes, too.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 164 insertions, 0 deletions

diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c
new file mode 100644
index 000000000000..2cd880e444d1
--- /dev/null
+++ b/net/mac80211/offchannel.c
@@ -0,0 +1,164 @@
+/*
+ * Off-channel operation helpers
+ *
+ * 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>
+ * Copyright 2009       Johannes Berg <johannes@sipsolutions.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 <net/mac80211.h>
+#include "ieee80211_i.h"
+
+/*
+ * inform AP that we will go to sleep so that it will buffer the frames
+ * while we scan
+ */
+static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata)
+{
+        struct ieee80211_local *local = sdata->local;
+
+        local->offchannel_ps_enabled = false;
+
+        /* FIXME: what to do when local->pspolling is true? */
+
+        del_timer_sync(&local->dynamic_ps_timer);
+        cancel_work_sync(&local->dynamic_ps_enable_work);
+
+        if (local->hw.conf.flags & IEEE80211_CONF_PS) {
+                local->offchannel_ps_enabled = true;
+                local->hw.conf.flags &= ~IEEE80211_CONF_PS;
+                ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+        }
+
+        if (!(local->offchannel_ps_enabled) ||
+            !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
+                /*
+                 * If power save was enabled, no need to send a nullfunc
+                 * frame because AP knows that we are sleeping. But if the
+                 * hardware is creating the nullfunc frame for power save
+                 * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
+                 * enabled) and power save was enabled, the firmware just
+                 * sent a null frame with power save disabled. So we need
+                 * to send a new nullfunc frame to inform the AP that we
+                 * are again sleeping.
+                 */
+                ieee80211_send_nullfunc(local, sdata, 1);
+}
+
+/* inform AP that we are awake again, unless power save is enabled */
+static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
+{
+        struct ieee80211_local *local = sdata->local;
+
+        if (!local->ps_sdata)
+                ieee80211_send_nullfunc(local, sdata, 0);
+        else if (local->offchannel_ps_enabled) {
+                /*
+                 * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
+                 * will send a nullfunc frame with the powersave bit set
+                 * even though the AP already knows that we are sleeping.
+                 * This could be avoided by sending a null frame with power
+                 * save bit disabled before enabling the power save, but
+                 * this doesn't gain anything.
+                 *
+                 * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
+                 * to send a nullfunc frame because AP already knows that
+                 * we are sleeping, let's just enable power save mode in
+                 * hardware.
+                 */
+                local->hw.conf.flags |= IEEE80211_CONF_PS;
+                ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+        } else if (local->hw.conf.dynamic_ps_timeout > 0) {
+                /*
+                 * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
+                 * had been running before leaving the operating channel,
+                 * restart the timer now and send a nullfunc frame to inform
+                 * the AP that we are awake.
+                 */
+                ieee80211_send_nullfunc(local, sdata, 0);
+                mod_timer(&local->dynamic_ps_timer, jiffies +
+                          msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
+        }
+}
+
+void ieee80211_offchannel_stop_beaconing(struct ieee80211_local *local)
+{
+        struct ieee80211_sub_if_data *sdata;
+
+        mutex_lock(&local->iflist_mtx);
+        list_for_each_entry(sdata, &local->interfaces, list) {
+                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_bss_info_change_notify(
+                                sdata, BSS_CHANGED_BEACON_ENABLED);
+
+                /*
+                 * only handle non-STA interfaces here, STA interfaces
+                 * are handled in ieee80211_offchannel_stop_station(),
+                 * e.g., from the background scan state machine
+                 */
+                if (sdata->vif.type != NL80211_IFTYPE_STATION)
+                        netif_stop_queue(sdata->dev);
+        }
+        mutex_unlock(&local->iflist_mtx);
+}
+
+void ieee80211_offchannel_stop_station(struct ieee80211_local *local)
+{
+        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 (!ieee80211_sdata_running(sdata))
+                        continue;
+
+                if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+                        netif_stop_queue(sdata->dev);
+                        if (sdata->u.mgd.associated)
+                                ieee80211_offchannel_ps_enable(sdata);
+                }
+        }
+        mutex_unlock(&local->iflist_mtx);
+}
+
+void ieee80211_offchannel_return(struct ieee80211_local *local,
+                                 bool enable_beaconing)
+{
+        struct ieee80211_sub_if_data *sdata;
+
+        mutex_lock(&local->iflist_mtx);
+        list_for_each_entry(sdata, &local->interfaces, list) {
+                if (!ieee80211_sdata_running(sdata))
+                        continue;
+
+                /* Tell AP we're back */
+                if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+                        if (sdata->u.mgd.associated)
+                                ieee80211_offchannel_ps_disable(sdata);
+                        netif_wake_queue(sdata->dev);
+                }
+
+                /* re-enable beaconing */
+                if (enable_beaconing &&
+                    (sdata->vif.type == NL80211_IFTYPE_AP ||
+                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
+                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT))
+                        ieee80211_bss_info_change_notify(
+                                sdata, BSS_CHANGED_BEACON_ENABLED);
+        }
+        mutex_unlock(&local->iflist_mtx);
+}