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 #include "driver-trace.h"
  18
  19 /*
  20  * inform AP that we will go to sleep so that it will buffer the frames
  21  * while we scan
  22  */
  23 static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata)
  24 {
  25         struct ieee80211_local *local = sdata->local;
  26         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
  27
  28         local->offchannel_ps_enabled = false;
  29
  30         /* FIXME: what to do when local->pspolling is true? */
  31
  32         del_timer_sync(&local->dynamic_ps_timer);
  33         del_timer_sync(&ifmgd->bcn_mon_timer);
  34         del_timer_sync(&ifmgd->conn_mon_timer);
  35
  36         cancel_work_sync(&local->dynamic_ps_enable_work);
  37
  38         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
  39                 local->offchannel_ps_enabled = true;
  40                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
  41                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  42         }
  43
  44         if (!(local->offchannel_ps_enabled) ||
  45             !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
  46                 /*
  47                  * If power save was enabled, no need to send a nullfunc
  48                  * frame because AP knows that we are sleeping. But if the
  49                  * hardware is creating the nullfunc frame for power save
  50                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
  51                  * enabled) and power save was enabled, the firmware just
  52                  * sent a null frame with power save disabled. So we need
  53                  * to send a new nullfunc frame to inform the AP that we
  54                  * are again sleeping.
  55                  */
  56                 ieee80211_send_nullfunc(local, sdata, 1);
  57 }
  58
  59 /* inform AP that we are awake again, unless power save is enabled */
  60 static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
  61 {
  62         struct ieee80211_local *local = sdata->local;
  63
  64         if (!local->ps_sdata)
  65                 ieee80211_send_nullfunc(local, sdata, 0);
  66         else if (local->offchannel_ps_enabled) {
  67                 /*
  68                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
  69                  * will send a nullfunc frame with the powersave bit set
  70                  * even though the AP already knows that we are sleeping.
  71                  * This could be avoided by sending a null frame with power
  72                  * save bit disabled before enabling the power save, but
  73                  * this doesn't gain anything.
  74                  *
  75                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
  76                  * to send a nullfunc frame because AP already knows that
  77                  * we are sleeping, let's just enable power save mode in
  78                  * hardware.
  79                  */
  80                 local->hw.conf.flags |= IEEE80211_CONF_PS;
  81                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  82         } else if (local->hw.conf.dynamic_ps_timeout > 0) {
  83                 /*
  84                  * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
  85                  * had been running before leaving the operating channel,
  86                  * restart the timer now and send a nullfunc frame to inform
  87                  * the AP that we are awake.
  88                  */
  89                 ieee80211_send_nullfunc(local, sdata, 0);
  90                 mod_timer(&local->dynamic_ps_timer, jiffies +
  91                           msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
  92         }
  93
  94         ieee80211_sta_reset_beacon_monitor(sdata);
  95         ieee80211_sta_reset_conn_monitor(sdata);
  96 }
  97
  98 void ieee80211_offchannel_stop_beaconing(struct ieee80211_local *local)
  99 {
 100         struct ieee80211_sub_if_data *sdata;
 101
 102         mutex_lock(&local->iflist_mtx);
 103         list_for_each_entry(sdata, &local->interfaces, list) {
 104                 if (!ieee80211_sdata_running(sdata))
 105                         continue;
 106
 107                 /* disable beaconing */
 108                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 109                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 110                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 111                         ieee80211_bss_info_change_notify(
 112                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 113
 114                 /*
 115                  * only handle non-STA interfaces here, STA interfaces
 116                  * are handled in ieee80211_offchannel_stop_station(),
 117                  * e.g., from the background scan state machine.
 118                  *
 119                  * In addition, do not stop monitor interface to allow it to be
 120                  * used from user space controlled off-channel operations.
 121                  */
 122                 if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 123                     sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 124                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 125                         netif_tx_stop_all_queues(sdata->dev);
 126                 }
 127         }
 128         mutex_unlock(&local->iflist_mtx);
 129 }
 130
 131 void ieee80211_offchannel_stop_station(struct ieee80211_local *local)
 132 {
 133         struct ieee80211_sub_if_data *sdata;
 134
 135         /*
 136          * notify the AP about us leaving the channel and stop all STA interfaces
 137          */
 138         mutex_lock(&local->iflist_mtx);
 139         list_for_each_entry(sdata, &local->interfaces, list) {
 140                 if (!ieee80211_sdata_running(sdata))
 141                         continue;
 142
 143                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 144                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 145                         netif_tx_stop_all_queues(sdata->dev);
 146                         if (sdata->u.mgd.associated)
 147                                 ieee80211_offchannel_ps_enable(sdata);
 148                 }
 149         }
 150         mutex_unlock(&local->iflist_mtx);
 151 }
 152
 153 void ieee80211_offchannel_return(struct ieee80211_local *local,
 154                                  bool enable_beaconing)
 155 {
 156         struct ieee80211_sub_if_data *sdata;
 157
 158         mutex_lock(&local->iflist_mtx);
 159         list_for_each_entry(sdata, &local->interfaces, list) {
 160                 if (!ieee80211_sdata_running(sdata))
 161                         continue;
 162
 163                 /* Tell AP we're back */
 164                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 165                         if (sdata->u.mgd.associated)
 166                                 ieee80211_offchannel_ps_disable(sdata);
 167                 }
 168
 169                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 170                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 171                         /*
 172                          * This may wake up queues even though the driver
 173                          * currently has them stopped. This is not very
 174                          * likely, since the driver won't have gotten any
 175                          * (or hardly any) new packets while we weren't
 176                          * on the right channel, and even if it happens
 177                          * it will at most lead to queueing up one more
 178                          * packet per queue in mac80211 rather than on
 179                          * the interface qdisc.
 180                          */
 181                         netif_tx_wake_all_queues(sdata->dev);
 182                 }
 183
 184                 /* re-enable beaconing */
 185                 if (enable_beaconing &&
 186                     (sdata->vif.type == NL80211_IFTYPE_AP ||
 187                      sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 188                      sdata->vif.type == NL80211_IFTYPE_MESH_POINT))
 189                         ieee80211_bss_info_change_notify(
 190                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 191         }
 192         mutex_unlock(&local->iflist_mtx);
 193 }
 194
 195 static void ieee80211_hw_roc_start(struct work_struct *work)
 196 {
 197         struct ieee80211_local *local =
 198                 container_of(work, struct ieee80211_local, hw_roc_start);
 199         struct ieee80211_sub_if_data *sdata;
 200
 201         mutex_lock(&local->mtx);
 202
 203         if (!local->hw_roc_channel) {
 204                 mutex_unlock(&local->mtx);
 205                 return;
 206         }
 207
 208         ieee80211_recalc_idle(local);
 209
 210         if (local->hw_roc_skb) {
 211                 sdata = IEEE80211_DEV_TO_SUB_IF(local->hw_roc_dev);
 212                 ieee80211_tx_skb(sdata, local->hw_roc_skb);
 213                 local->hw_roc_skb = NULL;
 214         } else {
 215                 cfg80211_ready_on_channel(local->hw_roc_dev,
 216                                           local->hw_roc_cookie,
 217                                           local->hw_roc_channel,
 218                                           local->hw_roc_channel_type,
 219                                           local->hw_roc_duration,
 220                                           GFP_KERNEL);
 221         }
 222
 223         mutex_unlock(&local->mtx);
 224 }
 225
 226 void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
 227 {
 228         struct ieee80211_local *local = hw_to_local(hw);
 229
 230         trace_api_ready_on_channel(local);
 231
 232         ieee80211_queue_work(hw, &local->hw_roc_start);
 233 }
 234 EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
 235
 236 static void ieee80211_hw_roc_done(struct work_struct *work)
 237 {
 238         struct ieee80211_local *local =
 239                 container_of(work, struct ieee80211_local, hw_roc_done);
 240
 241         mutex_lock(&local->mtx);
 242
 243         if (!local->hw_roc_channel) {
 244                 mutex_unlock(&local->mtx);
 245                 return;
 246         }
 247
 248         if (!local->hw_roc_for_tx)
 249                 cfg80211_remain_on_channel_expired(local->hw_roc_dev,
 250                                                    local->hw_roc_cookie,
 251                                                    local->hw_roc_channel,
 252                                                    local->hw_roc_channel_type,
 253                                                    GFP_KERNEL);
 254
 255         local->hw_roc_channel = NULL;
 256         local->hw_roc_cookie = 0;
 257
 258         ieee80211_recalc_idle(local);
 259
 260         mutex_unlock(&local->mtx);
 261 }
 262
 263 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 264 {
 265         struct ieee80211_local *local = hw_to_local(hw);
 266
 267         trace_api_remain_on_channel_expired(local);
 268
 269         ieee80211_queue_work(hw, &local->hw_roc_done);
 270 }
 271 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 272
 273 void ieee80211_hw_roc_setup(struct ieee80211_local *local)
 274 {
 275         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 276         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 277 }