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         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
  26
  27         local->offchannel_ps_enabled = false;
  28
  29         /* FIXME: what to do when local->pspolling is true? */
  30
  31         del_timer_sync(&local->dynamic_ps_timer);
  32         del_timer_sync(&ifmgd->bcn_mon_timer);
  33         del_timer_sync(&ifmgd->conn_mon_timer);
  34
  35         cancel_work_sync(&local->dynamic_ps_enable_work);
  36
  37         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
  38                 local->offchannel_ps_enabled = true;
  39                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
  40                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  41         }
  42
  43         if (!(local->offchannel_ps_enabled) ||
  44             !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
  45                 /*
  46                  * If power save was enabled, no need to send a nullfunc
  47                  * frame because AP knows that we are sleeping. But if the
  48                  * hardware is creating the nullfunc frame for power save
  49                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
  50                  * enabled) and power save was enabled, the firmware just
  51                  * sent a null frame with power save disabled. So we need
  52                  * to send a new nullfunc frame to inform the AP that we
  53                  * are again sleeping.
  54                  */
  55                 ieee80211_send_nullfunc(local, sdata, 1);
  56 }
  57
  58 /* inform AP that we are awake again, unless power save is enabled */
  59 static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
  60 {
  61         struct ieee80211_local *local = sdata->local;
  62
  63         if (!local->ps_sdata)
  64                 ieee80211_send_nullfunc(local, sdata, 0);
  65         else if (local->offchannel_ps_enabled) {
  66                 /*
  67                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
  68                  * will send a nullfunc frame with the powersave bit set
  69                  * even though the AP already knows that we are sleeping.
  70                  * This could be avoided by sending a null frame with power
  71                  * save bit disabled before enabling the power save, but
  72                  * this doesn't gain anything.
  73                  *
  74                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
  75                  * to send a nullfunc frame because AP already knows that
  76                  * we are sleeping, let's just enable power save mode in
  77                  * hardware.
  78                  */
  79                 local->hw.conf.flags |= IEEE80211_CONF_PS;
  80                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  81         } else if (local->hw.conf.dynamic_ps_timeout > 0) {
  82                 /*
  83                  * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
  84                  * had been running before leaving the operating channel,
  85                  * restart the timer now and send a nullfunc frame to inform
  86                  * the AP that we are awake.
  87                  */
  88                 ieee80211_send_nullfunc(local, sdata, 0);
  89                 mod_timer(&local->dynamic_ps_timer, jiffies +
  90                           msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
  91         }
  92
  93         ieee80211_sta_reset_beacon_monitor(sdata);
  94         ieee80211_sta_reset_conn_monitor(sdata);
  95 }
  96
  97 void ieee80211_offchannel_stop_beaconing(struct ieee80211_local *local)
  98 {
  99         struct ieee80211_sub_if_data *sdata;
 100
 101         mutex_lock(&local->iflist_mtx);
 102         list_for_each_entry(sdata, &local->interfaces, list) {
 103                 if (!ieee80211_sdata_running(sdata))
 104                         continue;
 105
 106                 /* disable beaconing */
 107                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 108                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 109                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 110                         ieee80211_bss_info_change_notify(
 111                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 112
 113                 /*
 114                  * only handle non-STA interfaces here, STA interfaces
 115                  * are handled in ieee80211_offchannel_stop_station(),
 116                  * e.g., from the background scan state machine.
 117                  *
 118                  * In addition, do not stop monitor interface to allow it to be
 119                  * used from user space controlled off-channel operations.
 120                  */
 121                 if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 122                     sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 123                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 124                         netif_tx_stop_all_queues(sdata->dev);
 125                 }
 126         }
 127         mutex_unlock(&local->iflist_mtx);
 128 }
 129
 130 void ieee80211_offchannel_stop_station(struct ieee80211_local *local)
 131 {
 132         struct ieee80211_sub_if_data *sdata;
 133
 134         /*
 135          * notify the AP about us leaving the channel and stop all STA interfaces
 136          */
 137         mutex_lock(&local->iflist_mtx);
 138         list_for_each_entry(sdata, &local->interfaces, list) {
 139                 if (!ieee80211_sdata_running(sdata))
 140                         continue;
 141
 142                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 143                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 144                         netif_tx_stop_all_queues(sdata->dev);
 145                         if (sdata->u.mgd.associated)
 146                                 ieee80211_offchannel_ps_enable(sdata);
 147                 }
 148         }
 149         mutex_unlock(&local->iflist_mtx);
 150 }
 151
 152 void ieee80211_offchannel_return(struct ieee80211_local *local,
 153                                  bool enable_beaconing)
 154 {
 155         struct ieee80211_sub_if_data *sdata;
 156
 157         mutex_lock(&local->iflist_mtx);
 158         list_for_each_entry(sdata, &local->interfaces, list) {
 159                 if (!ieee80211_sdata_running(sdata))
 160                         continue;
 161
 162                 /* Tell AP we're back */
 163                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 164                         if (sdata->u.mgd.associated)
 165                                 ieee80211_offchannel_ps_disable(sdata);
 166                 }
 167
 168                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 169                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 170                         /*
 171                          * This may wake up queues even though the driver
 172                          * currently has them stopped. This is not very
 173                          * likely, since the driver won't have gotten any
 174                          * (or hardly any) new packets while we weren't
 175                          * on the right channel, and even if it happens
 176                          * it will at most lead to queueing up one more
 177                          * packet per queue in mac80211 rather than on
 178                          * the interface qdisc.
 179                          */
 180                         netif_tx_wake_all_queues(sdata->dev);
 181                 }
 182
 183                 /* re-enable beaconing */
 184                 if (enable_beaconing &&
 185                     (sdata->vif.type == NL80211_IFTYPE_AP ||
 186                      sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 187                      sdata->vif.type == NL80211_IFTYPE_MESH_POINT))
 188                         ieee80211_bss_info_change_notify(
 189                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 190         }
 191         mutex_unlock(&local->iflist_mtx);
 192 }