/*
* 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.
*
* In addition, do not stop monitor interface to allow it to be
* used from user space controlled off-channel operations.
*/
if (sdata->vif.type != NL80211_IFTYPE_STATION &&
sdata->vif.type != NL80211_IFTYPE_MONITOR) {
set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
netif_tx_stop_all_queues(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) {
set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
netif_tx_stop_all_queues(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);
}
if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
/*
* 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);
}
/* 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);
}
