5b714c6a37
Somebody noticed this problem, and I outlined to them how to fix it, but haven't heard back from them. So while I was adding the state field I figured I could use it to fix it. The problem, as I understand it, is that when we go offchannel while the driver has a queue stopped, the driver will likely start draining the queue and then enable it while offchannel. This in turn will enable the interface queue, and that leads to transmitting data frames on the wrong channel. Fix this by keeping track of offchannel status per interface, and not enabling the interface queues on interfaces that are offchannel when the driver enables a queue. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
186 lines
6.0 KiB
C
186 lines
6.0 KiB
C
/*
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* Off-channel operation helpers
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*
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* Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
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* Copyright 2004, Instant802 Networks, Inc.
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* Copyright 2005, Devicescape Software, Inc.
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* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
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* Copyright 2007, Michael Wu <flamingice@sourmilk.net>
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* Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <net/mac80211.h>
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#include "ieee80211_i.h"
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/*
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* inform AP that we will go to sleep so that it will buffer the frames
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* while we scan
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*/
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static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata)
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{
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struct ieee80211_local *local = sdata->local;
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local->offchannel_ps_enabled = false;
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/* FIXME: what to do when local->pspolling is true? */
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del_timer_sync(&local->dynamic_ps_timer);
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cancel_work_sync(&local->dynamic_ps_enable_work);
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if (local->hw.conf.flags & IEEE80211_CONF_PS) {
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local->offchannel_ps_enabled = true;
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local->hw.conf.flags &= ~IEEE80211_CONF_PS;
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ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
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}
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if (!(local->offchannel_ps_enabled) ||
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!(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
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/*
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* If power save was enabled, no need to send a nullfunc
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* frame because AP knows that we are sleeping. But if the
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* hardware is creating the nullfunc frame for power save
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* status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
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* enabled) and power save was enabled, the firmware just
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* sent a null frame with power save disabled. So we need
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* to send a new nullfunc frame to inform the AP that we
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* are again sleeping.
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*/
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ieee80211_send_nullfunc(local, sdata, 1);
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}
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/* inform AP that we are awake again, unless power save is enabled */
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static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
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{
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struct ieee80211_local *local = sdata->local;
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if (!local->ps_sdata)
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ieee80211_send_nullfunc(local, sdata, 0);
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else if (local->offchannel_ps_enabled) {
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/*
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* In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
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* will send a nullfunc frame with the powersave bit set
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* even though the AP already knows that we are sleeping.
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* This could be avoided by sending a null frame with power
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* save bit disabled before enabling the power save, but
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* this doesn't gain anything.
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*
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* When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
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* to send a nullfunc frame because AP already knows that
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* we are sleeping, let's just enable power save mode in
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* hardware.
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*/
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local->hw.conf.flags |= IEEE80211_CONF_PS;
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ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
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} else if (local->hw.conf.dynamic_ps_timeout > 0) {
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/*
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* If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
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* had been running before leaving the operating channel,
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* restart the timer now and send a nullfunc frame to inform
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* the AP that we are awake.
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*/
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ieee80211_send_nullfunc(local, sdata, 0);
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mod_timer(&local->dynamic_ps_timer, jiffies +
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msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
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}
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}
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void ieee80211_offchannel_stop_beaconing(struct ieee80211_local *local)
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{
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struct ieee80211_sub_if_data *sdata;
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mutex_lock(&local->iflist_mtx);
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list_for_each_entry(sdata, &local->interfaces, list) {
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if (!ieee80211_sdata_running(sdata))
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continue;
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/* disable beaconing */
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if (sdata->vif.type == NL80211_IFTYPE_AP ||
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sdata->vif.type == NL80211_IFTYPE_ADHOC ||
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sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
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ieee80211_bss_info_change_notify(
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sdata, BSS_CHANGED_BEACON_ENABLED);
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/*
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* only handle non-STA interfaces here, STA interfaces
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* are handled in ieee80211_offchannel_stop_station(),
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* e.g., from the background scan state machine.
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*
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* In addition, do not stop monitor interface to allow it to be
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* used from user space controlled off-channel operations.
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*/
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if (sdata->vif.type != NL80211_IFTYPE_STATION &&
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sdata->vif.type != NL80211_IFTYPE_MONITOR) {
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set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
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netif_tx_stop_all_queues(sdata->dev);
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}
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}
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mutex_unlock(&local->iflist_mtx);
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}
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void ieee80211_offchannel_stop_station(struct ieee80211_local *local)
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{
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struct ieee80211_sub_if_data *sdata;
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/*
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* notify the AP about us leaving the channel and stop all STA interfaces
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*/
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mutex_lock(&local->iflist_mtx);
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list_for_each_entry(sdata, &local->interfaces, list) {
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if (!ieee80211_sdata_running(sdata))
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continue;
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if (sdata->vif.type == NL80211_IFTYPE_STATION) {
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set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
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netif_tx_stop_all_queues(sdata->dev);
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if (sdata->u.mgd.associated)
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ieee80211_offchannel_ps_enable(sdata);
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}
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}
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mutex_unlock(&local->iflist_mtx);
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}
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void ieee80211_offchannel_return(struct ieee80211_local *local,
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bool enable_beaconing)
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{
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struct ieee80211_sub_if_data *sdata;
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mutex_lock(&local->iflist_mtx);
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list_for_each_entry(sdata, &local->interfaces, list) {
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if (!ieee80211_sdata_running(sdata))
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continue;
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/* Tell AP we're back */
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if (sdata->vif.type == NL80211_IFTYPE_STATION) {
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if (sdata->u.mgd.associated)
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ieee80211_offchannel_ps_disable(sdata);
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}
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if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
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clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
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/*
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* This may wake up queues even though the driver
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* currently has them stopped. This is not very
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* likely, since the driver won't have gotten any
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* (or hardly any) new packets while we weren't
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* on the right channel, and even if it happens
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* it will at most lead to queueing up one more
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* packet per queue in mac80211 rather than on
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* the interface qdisc.
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*/
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netif_tx_wake_all_queues(sdata->dev);
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}
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/* re-enable beaconing */
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if (enable_beaconing &&
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(sdata->vif.type == NL80211_IFTYPE_AP ||
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sdata->vif.type == NL80211_IFTYPE_ADHOC ||
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sdata->vif.type == NL80211_IFTYPE_MESH_POINT))
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ieee80211_bss_info_change_notify(
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sdata, BSS_CHANGED_BEACON_ENABLED);
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}
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mutex_unlock(&local->iflist_mtx);
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}
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