net/mac80211/offchannel.c - kernel/windcharger - Git at Google

 /*
  * 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 <linux/export.h>
 #include <net/mac80211.h>
 #include "ieee80211_i.h"
 #include "driver-trace.h"

 /*
  * Tell our hardware to disable PS.
  * Optionally inform AP that we will go to sleep so that it will buffer
  * the frames while we are doing off-channel work.  This is optional
  * because we *may* be doing work on-operating channel, and want our
  * hardware unconditionally awake, but still let the AP send us normal frames.
  */
 static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata,
 					   bool tell_ap)
 {
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;

 	local->offchannel_ps_enabled = false;

 	/* FIXME: what to do when local->pspolling is true? */

 	del_timer_sync(&local->dynamic_ps_timer);
 	del_timer_sync(&ifmgd->bcn_mon_timer);
 	del_timer_sync(&ifmgd->conn_mon_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 (tell_ap && (!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.
 		 */
 		/* TODO:  Only set hardware if CONF_PS changed?
 		 * TODO:  Should we set offchannel_ps_enabled to false?
 		 */
 		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));
 	}

 	ieee80211_sta_reset_beacon_monitor(sdata);
 	ieee80211_sta_reset_conn_monitor(sdata);
 }

 void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local,
 				    bool offchannel_ps_enable)
 {
 	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_MONITOR)
 			set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);

 		/* Check to see if we should 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);

 		if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 			netif_tx_stop_all_queues(sdata->dev);
 			if (offchannel_ps_enable &&
 			    (sdata->vif.type == NL80211_IFTYPE_STATION) &&
 			    sdata->u.mgd.associated)
 				ieee80211_offchannel_ps_enable(sdata, true);
 		}
 	}
 	mutex_unlock(&local->iflist_mtx);
 }

 void ieee80211_offchannel_return(struct ieee80211_local *local,
 				 bool offchannel_ps_disable)
 {
 	struct ieee80211_sub_if_data *sdata;

 	mutex_lock(&local->iflist_mtx);
 	list_for_each_entry(sdata, &local->interfaces, list) {
 		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 			clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);

 		if (!ieee80211_sdata_running(sdata))
 			continue;

 		/* Tell AP we're back */
 		if (offchannel_ps_disable &&
 		    sdata->vif.type == NL80211_IFTYPE_STATION) {
 			if (sdata->u.mgd.associated)
 				ieee80211_offchannel_ps_disable(sdata);
 		}

 		if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 			/*
 			 * This may wake up queues even though the driver
 			 * currently has them stopped. This is not very
 			 * likely, since the driver won't have gotten any
 			 * (or hardly any) new packets while we weren't
 			 * on the right channel, and even if it happens
 			 * it will at most lead to queueing up one more
 			 * packet per queue in mac80211 rather than on
 			 * the interface qdisc.
 			 */
 			netif_tx_wake_all_queues(sdata->dev);
 		}

 		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);
 	}
 	mutex_unlock(&local->iflist_mtx);
 }

 static void ieee80211_hw_roc_start(struct work_struct *work)
 {
 	struct ieee80211_local *local =
 		container_of(work, struct ieee80211_local, hw_roc_start);
 	struct ieee80211_sub_if_data *sdata;

 	mutex_lock(&local->mtx);

 	if (!local->hw_roc_channel) {
 		mutex_unlock(&local->mtx);
 		return;
 	}

 	if (local->hw_roc_skb) {
 		sdata = IEEE80211_DEV_TO_SUB_IF(local->hw_roc_dev);
 		ieee80211_tx_skb(sdata, local->hw_roc_skb);
 		local->hw_roc_skb = NULL;
 	} else {
 		cfg80211_ready_on_channel(local->hw_roc_dev,
 					  local->hw_roc_cookie,
 					  local->hw_roc_channel,
 					  local->hw_roc_channel_type,
 					  local->hw_roc_duration,
 					  GFP_KERNEL);
 	}

 	ieee80211_recalc_idle(local);

 	mutex_unlock(&local->mtx);
 }

 void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
 {
 	struct ieee80211_local *local = hw_to_local(hw);

 	trace_api_ready_on_channel(local);

 	ieee80211_queue_work(hw, &local->hw_roc_start);
 }
 EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);

 static void ieee80211_hw_roc_done(struct work_struct *work)
 {
 	struct ieee80211_local *local =
 		container_of(work, struct ieee80211_local, hw_roc_done);

 	mutex_lock(&local->mtx);

 	if (!local->hw_roc_channel) {
 		mutex_unlock(&local->mtx);
 		return;
 	}

 	if (!local->hw_roc_for_tx)
 		cfg80211_remain_on_channel_expired(local->hw_roc_dev,
 						   local->hw_roc_cookie,
 						   local->hw_roc_channel,
 						   local->hw_roc_channel_type,
 						   GFP_KERNEL);

 	local->hw_roc_channel = NULL;
 	local->hw_roc_cookie = 0;

 	ieee80211_recalc_idle(local);

 	mutex_unlock(&local->mtx);
 }

 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 {
 	struct ieee80211_local *local = hw_to_local(hw);

 	trace_api_remain_on_channel_expired(local);

 	ieee80211_queue_work(hw, &local->hw_roc_done);
 }
 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);

 void ieee80211_hw_roc_setup(struct ieee80211_local *local)
 {
 	INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 	INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 }
	/*
	* 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 <linux/export.h>
	#include <net/mac80211.h>
	#include "ieee80211_i.h"
	#include "driver-trace.h"

	/*
	* Tell our hardware to disable PS.
	* Optionally inform AP that we will go to sleep so that it will buffer
	* the frames while we are doing off-channel work. This is optional
	* because we may be doing work on-operating channel, and want our
	* hardware unconditionally awake, but still let the AP send us normal frames.
	*/
	static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata,
	bool tell_ap)
	{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;

	local->offchannel_ps_enabled = false;

	/* FIXME: what to do when local->pspolling is true? */

	del_timer_sync(&local->dynamic_ps_timer);
	del_timer_sync(&ifmgd->bcn_mon_timer);
	del_timer_sync(&ifmgd->conn_mon_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 (tell_ap && (!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.
	*/
	/* TODO: Only set hardware if CONF_PS changed?
	* TODO: Should we set offchannel_ps_enabled to false?
	*/
	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));
	}

	ieee80211_sta_reset_beacon_monitor(sdata);
	ieee80211_sta_reset_conn_monitor(sdata);
	}

	void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local,
	bool offchannel_ps_enable)
	{
	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_MONITOR)
	set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);

	/* Check to see if we should 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);

	if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
	netif_tx_stop_all_queues(sdata->dev);
	if (offchannel_ps_enable &&
	(sdata->vif.type == NL80211_IFTYPE_STATION) &&
	sdata->u.mgd.associated)
	ieee80211_offchannel_ps_enable(sdata, true);
	}
	}
	mutex_unlock(&local->iflist_mtx);
	}

	void ieee80211_offchannel_return(struct ieee80211_local *local,
	bool offchannel_ps_disable)
	{
	struct ieee80211_sub_if_data *sdata;

	mutex_lock(&local->iflist_mtx);
	list_for_each_entry(sdata, &local->interfaces, list) {
	if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
	clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);

	if (!ieee80211_sdata_running(sdata))
	continue;

	/* Tell AP we're back */
	if (offchannel_ps_disable &&
	sdata->vif.type == NL80211_IFTYPE_STATION) {
	if (sdata->u.mgd.associated)
	ieee80211_offchannel_ps_disable(sdata);
	}

	if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
	/*
	* This may wake up queues even though the driver
	* currently has them stopped. This is not very
	* likely, since the driver won't have gotten any
	* (or hardly any) new packets while we weren't
	* on the right channel, and even if it happens
	* it will at most lead to queueing up one more
	* packet per queue in mac80211 rather than on
	* the interface qdisc.
	*/
	netif_tx_wake_all_queues(sdata->dev);
	}

	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);
	}
	mutex_unlock(&local->iflist_mtx);
	}

	static void ieee80211_hw_roc_start(struct work_struct *work)
	{
	struct ieee80211_local *local =
	container_of(work, struct ieee80211_local, hw_roc_start);
	struct ieee80211_sub_if_data *sdata;

	mutex_lock(&local->mtx);

	if (!local->hw_roc_channel) {
	mutex_unlock(&local->mtx);
	return;
	}

	if (local->hw_roc_skb) {
	sdata = IEEE80211_DEV_TO_SUB_IF(local->hw_roc_dev);
	ieee80211_tx_skb(sdata, local->hw_roc_skb);
	local->hw_roc_skb = NULL;
	} else {
	cfg80211_ready_on_channel(local->hw_roc_dev,
	local->hw_roc_cookie,
	local->hw_roc_channel,
	local->hw_roc_channel_type,
	local->hw_roc_duration,
	GFP_KERNEL);
	}

	ieee80211_recalc_idle(local);

	mutex_unlock(&local->mtx);
	}

	void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
	{
	struct ieee80211_local *local = hw_to_local(hw);

	trace_api_ready_on_channel(local);

	ieee80211_queue_work(hw, &local->hw_roc_start);
	}
	EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);

	static void ieee80211_hw_roc_done(struct work_struct *work)
	{
	struct ieee80211_local *local =
	container_of(work, struct ieee80211_local, hw_roc_done);

	mutex_lock(&local->mtx);

	if (!local->hw_roc_channel) {
	mutex_unlock(&local->mtx);
	return;
	}

	if (!local->hw_roc_for_tx)
	cfg80211_remain_on_channel_expired(local->hw_roc_dev,
	local->hw_roc_cookie,
	local->hw_roc_channel,
	local->hw_roc_channel_type,
	GFP_KERNEL);

	local->hw_roc_channel = NULL;
	local->hw_roc_cookie = 0;

	ieee80211_recalc_idle(local);

	mutex_unlock(&local->mtx);
	}

	void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
	{
	struct ieee80211_local *local = hw_to_local(hw);

	trace_api_remain_on_channel_expired(local);

	ieee80211_queue_work(hw, &local->hw_roc_done);
	}
	EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);

	void ieee80211_hw_roc_setup(struct ieee80211_local *local)
	{
	INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
	INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
	}