net/mac80211/offchannel.c

   1 /*
   2  * Off-channel operation helpers
   3  *
   4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   5  * Copyright 2004, Instant802 Networks, Inc.
   6  * Copyright 2005, Devicescape Software, Inc.
   7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   9  * Copyright 2009       Johannes Berg <johannes@sipsolutions.net>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15 #include <net/mac80211.h>
  16 #include "ieee80211_i.h"
  17
  18 /*
  19  * inform AP that we will go to sleep so that it will buffer the frames
  20  * while we scan
  21  */
  22 static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata)
  23 {
  24         struct ieee80211_local *local = sdata->local;
  25
  26         local->offchannel_ps_enabled = false;
  27
  28         /* FIXME: what to do when local->pspolling is true? */
  29
  30         del_timer_sync(&local->dynamic_ps_timer);
  31         cancel_work_sync(&local->dynamic_ps_enable_work);
  32
  33         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
  34                 local->offchannel_ps_enabled = true;
  35                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
  36                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  37         }
  38
  39         if (!(local->offchannel_ps_enabled) ||
  40             !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
  41                 /*
  42                  * If power save was enabled, no need to send a nullfunc
  43                  * frame because AP knows that we are sleeping. But if the
  44                  * hardware is creating the nullfunc frame for power save
  45                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
  46                  * enabled) and power save was enabled, the firmware just
  47                  * sent a null frame with power save disabled. So we need
  48                  * to send a new nullfunc frame to inform the AP that we
  49                  * are again sleeping.
  50                  */
  51                 ieee80211_send_nullfunc(local, sdata, 1);
  52 }
  53
  54 /* inform AP that we are awake again, unless power save is enabled */
  55 static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
  56 {
  57         struct ieee80211_local *local = sdata->local;
  58
  59         if (!local->ps_sdata)
  60                 ieee80211_send_nullfunc(local, sdata, 0);
  61         else if (local->offchannel_ps_enabled) {
  62                 /*
  63                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
  64                  * will send a nullfunc frame with the powersave bit set
  65                  * even though the AP already knows that we are sleeping.
  66                  * This could be avoided by sending a null frame with power
  67                  * save bit disabled before enabling the power save, but
  68                  * this doesn't gain anything.
  69                  *
  70                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
  71                  * to send a nullfunc frame because AP already knows that
  72                  * we are sleeping, let's just enable power save mode in
  73                  * hardware.
  74                  */
  75                 local->hw.conf.flags |= IEEE80211_CONF_PS;
  76                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  77         } else if (local->hw.conf.dynamic_ps_timeout > 0) {
  78                 /*
  79                  * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
  80                  * had been running before leaving the operating channel,
  81                  * restart the timer now and send a nullfunc frame to inform
  82                  * the AP that we are awake.
  83                  */
  84                 ieee80211_send_nullfunc(local, sdata, 0);
  85                 mod_timer(&local->dynamic_ps_timer, jiffies +
  86                           msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
  87         }
  88 }
  89
  90 void ieee80211_offchannel_stop_beaconing(struct ieee80211_local *local)
  91 {
  92         struct ieee80211_sub_if_data *sdata;
  93
  94         mutex_lock(&local->iflist_mtx);
  95         list_for_each_entry(sdata, &local->interfaces, list) {
  96                 if (!ieee80211_sdata_running(sdata))
  97                         continue;
  98
  99                 /* disable beaconing */
 100                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 101                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 102                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 103                         ieee80211_bss_info_change_notify(
 104                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 105
 106                 /*
 107                  * only handle non-STA interfaces here, STA interfaces
 108                  * are handled in ieee80211_offchannel_stop_station(),
 109                  * e.g., from the background scan state machine.
 110                  *
 111                  * In addition, do not stop monitor interface to allow it to be
 112                  * used from user space controlled off-channel operations.
 113                  */
 114                 if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 115                     sdata->vif.type != NL80211_IFTYPE_MONITOR)
 116                         netif_stop_queue(sdata->dev);
 117         }
 118         mutex_unlock(&local->iflist_mtx);
 119 }
 120
 121 void ieee80211_offchannel_stop_station(struct ieee80211_local *local)
 122 {
 123         struct ieee80211_sub_if_data *sdata;
 124
 125         /*
 126          * notify the AP about us leaving the channel and stop all STA interfaces
 127          */
 128         mutex_lock(&local->iflist_mtx);
 129         list_for_each_entry(sdata, &local->interfaces, list) {
 130                 if (!ieee80211_sdata_running(sdata))
 131                         continue;
 132
 133                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 134                         netif_stop_queue(sdata->dev);
 135                         if (sdata->u.mgd.associated)
 136                                 ieee80211_offchannel_ps_enable(sdata);
 137                 }
 138         }
 139         mutex_unlock(&local->iflist_mtx);
 140 }
 141
 142 void ieee80211_offchannel_return(struct ieee80211_local *local,
 143                                  bool enable_beaconing)
 144 {
 145         struct ieee80211_sub_if_data *sdata;
 146
 147         mutex_lock(&local->iflist_mtx);
 148         list_for_each_entry(sdata, &local->interfaces, list) {
 149                 if (!ieee80211_sdata_running(sdata))
 150                         continue;
 151
 152                 /* Tell AP we're back */
 153                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 154                         if (sdata->u.mgd.associated)
 155                                 ieee80211_offchannel_ps_disable(sdata);
 156                         netif_wake_queue(sdata->dev);
 157                 }
 158
 159                 /* re-enable beaconing */
 160                 if (enable_beaconing &&
 161                     (sdata->vif.type == NL80211_IFTYPE_AP ||
 162                      sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 163                      sdata->vif.type == NL80211_IFTYPE_MESH_POINT))
 164                         ieee80211_bss_info_change_notify(
 165                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 166         }
 167         mutex_unlock(&local->iflist_mtx);
 168 }