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  * Tell our hardware to disable PS.
  21  * Optionally inform AP that we will go to sleep so that it will buffer
  22  * the frames while we are doing off-channel work.  This is optional
  23  * because we *may* be doing work on-operating channel, and want our
  24  * hardware unconditionally awake, but still let the AP send us normal frames.
  25  */
  26 static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata,
  27                                            bool tell_ap)
  28 {
  29         struct ieee80211_local *local = sdata->local;
  30         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
  31
  32         local->offchannel_ps_enabled = false;
  33
  34         /* FIXME: what to do when local->pspolling is true? */
  35
  36         del_timer_sync(&local->dynamic_ps_timer);
  37         del_timer_sync(&ifmgd->bcn_mon_timer);
  38         del_timer_sync(&ifmgd->conn_mon_timer);
  39
  40         cancel_work_sync(&local->dynamic_ps_enable_work);
  41
  42         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
  43                 local->offchannel_ps_enabled = true;
  44                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
  45                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  46         }
  47
  48         if (tell_ap && (!local->offchannel_ps_enabled ||
  49                         !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)))
  50                 /*
  51                  * If power save was enabled, no need to send a nullfunc
  52                  * frame because AP knows that we are sleeping. But if the
  53                  * hardware is creating the nullfunc frame for power save
  54                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
  55                  * enabled) and power save was enabled, the firmware just
  56                  * sent a null frame with power save disabled. So we need
  57                  * to send a new nullfunc frame to inform the AP that we
  58                  * are again sleeping.
  59                  */
  60                 ieee80211_send_nullfunc(local, sdata, 1);
  61 }
  62
  63 /* inform AP that we are awake again, unless power save is enabled */
  64 static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
  65 {
  66         struct ieee80211_local *local = sdata->local;
  67
  68         if (!local->ps_sdata)
  69                 ieee80211_send_nullfunc(local, sdata, 0);
  70         else if (local->offchannel_ps_enabled) {
  71                 /*
  72                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
  73                  * will send a nullfunc frame with the powersave bit set
  74                  * even though the AP already knows that we are sleeping.
  75                  * This could be avoided by sending a null frame with power
  76                  * save bit disabled before enabling the power save, but
  77                  * this doesn't gain anything.
  78                  *
  79                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
  80                  * to send a nullfunc frame because AP already knows that
  81                  * we are sleeping, let's just enable power save mode in
  82                  * hardware.
  83                  */
  84                 /* TODO:  Only set hardware if CONF_PS changed?
  85                  * TODO:  Should we set offchannel_ps_enabled to false?
  86                  */
  87                 local->hw.conf.flags |= IEEE80211_CONF_PS;
  88                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  89         } else if (local->hw.conf.dynamic_ps_timeout > 0) {
  90                 /*
  91                  * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
  92                  * had been running before leaving the operating channel,
  93                  * restart the timer now and send a nullfunc frame to inform
  94                  * the AP that we are awake.
  95                  */
  96                 ieee80211_send_nullfunc(local, sdata, 0);
  97                 mod_timer(&local->dynamic_ps_timer, jiffies +
  98                           msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
  99         }
 100
 101         ieee80211_sta_reset_beacon_monitor(sdata);
 102         ieee80211_sta_reset_conn_monitor(sdata);
 103 }
 104
 105 void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local,
 106                                     bool offchannel_ps_enable)
 107 {
 108         struct ieee80211_sub_if_data *sdata;
 109
 110         /*
 111          * notify the AP about us leaving the channel and stop all
 112          * STA interfaces.
 113          */
 114         mutex_lock(&local->iflist_mtx);
 115         list_for_each_entry(sdata, &local->interfaces, list) {
 116                 if (!ieee80211_sdata_running(sdata))
 117                         continue;
 118
 119                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 120                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 121
 122                 /* Check to see if we should disable beaconing. */
 123                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 124                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 125                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 126                         ieee80211_bss_info_change_notify(
 127                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 128
 129                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 130                         netif_tx_stop_all_queues(sdata->dev);
 131                         if (offchannel_ps_enable &&
 132                             (sdata->vif.type == NL80211_IFTYPE_STATION) &&
 133                             sdata->u.mgd.associated)
 134                                 ieee80211_offchannel_ps_enable(sdata, true);
 135                 }
 136         }
 137         mutex_unlock(&local->iflist_mtx);
 138 }
 139
 140 void ieee80211_offchannel_enable_all_ps(struct ieee80211_local *local,
 141                                         bool tell_ap)
 142 {
 143         struct ieee80211_sub_if_data *sdata;
 144
 145         mutex_lock(&local->iflist_mtx);
 146         list_for_each_entry(sdata, &local->interfaces, list) {
 147                 if (!ieee80211_sdata_running(sdata))
 148                         continue;
 149
 150                 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 151                     sdata->u.mgd.associated)
 152                         ieee80211_offchannel_ps_enable(sdata, tell_ap);
 153         }
 154         mutex_unlock(&local->iflist_mtx);
 155 }
 156
 157 void ieee80211_offchannel_return(struct ieee80211_local *local,
 158                                  bool enable_beaconing,
 159                                  bool offchannel_ps_disable)
 160 {
 161         struct ieee80211_sub_if_data *sdata;
 162
 163         mutex_lock(&local->iflist_mtx);
 164         list_for_each_entry(sdata, &local->interfaces, list) {
 165                 if (!ieee80211_sdata_running(sdata))
 166                         continue;
 167
 168                 /* Tell AP we're back */
 169                 if (offchannel_ps_disable &&
 170                     sdata->vif.type == NL80211_IFTYPE_STATION) {
 171                         if (sdata->u.mgd.associated)
 172                                 ieee80211_offchannel_ps_disable(sdata);
 173                 }
 174
 175                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 176                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 177                         /*
 178                          * This may wake up queues even though the driver
 179                          * currently has them stopped. This is not very
 180                          * likely, since the driver won't have gotten any
 181                          * (or hardly any) new packets while we weren't
 182                          * on the right channel, and even if it happens
 183                          * it will at most lead to queueing up one more
 184                          * packet per queue in mac80211 rather than on
 185                          * the interface qdisc.
 186                          */
 187                         netif_tx_wake_all_queues(sdata->dev);
 188                 }
 189
 190                 /* Check to see if we should re-enable beaconing */
 191                 if (enable_beaconing &&
 192                     (sdata->vif.type == NL80211_IFTYPE_AP ||
 193                      sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 194                      sdata->vif.type == NL80211_IFTYPE_MESH_POINT))
 195                         ieee80211_bss_info_change_notify(
 196                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 197         }
 198         mutex_unlock(&local->iflist_mtx);
 199 }
 200
 201 static void ieee80211_hw_roc_start(struct work_struct *work)
 202 {
 203         struct ieee80211_local *local =
 204                 container_of(work, struct ieee80211_local, hw_roc_start);
 205         struct ieee80211_sub_if_data *sdata;
 206
 207         mutex_lock(&local->mtx);
 208
 209         if (!local->hw_roc_channel) {
 210                 mutex_unlock(&local->mtx);
 211                 return;
 212         }
 213
 214         ieee80211_recalc_idle(local);
 215
 216         if (local->hw_roc_skb) {
 217                 sdata = IEEE80211_DEV_TO_SUB_IF(local->hw_roc_dev);
 218                 ieee80211_tx_skb(sdata, local->hw_roc_skb);
 219                 local->hw_roc_skb = NULL;
 220         } else {
 221                 cfg80211_ready_on_channel(local->hw_roc_dev,
 222                                           local->hw_roc_cookie,
 223                                           local->hw_roc_channel,
 224                                           local->hw_roc_channel_type,
 225                                           local->hw_roc_duration,
 226                                           GFP_KERNEL);
 227         }
 228
 229         mutex_unlock(&local->mtx);
 230 }
 231
 232 void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
 233 {
 234         struct ieee80211_local *local = hw_to_local(hw);
 235
 236         trace_api_ready_on_channel(local);
 237
 238         ieee80211_queue_work(hw, &local->hw_roc_start);
 239 }
 240 EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
 241
 242 static void ieee80211_hw_roc_done(struct work_struct *work)
 243 {
 244         struct ieee80211_local *local =
 245                 container_of(work, struct ieee80211_local, hw_roc_done);
 246
 247         mutex_lock(&local->mtx);
 248
 249         if (!local->hw_roc_channel) {
 250                 mutex_unlock(&local->mtx);
 251                 return;
 252         }
 253
 254         if (!local->hw_roc_for_tx)
 255                 cfg80211_remain_on_channel_expired(local->hw_roc_dev,
 256                                                    local->hw_roc_cookie,
 257                                                    local->hw_roc_channel,
 258                                                    local->hw_roc_channel_type,
 259                                                    GFP_KERNEL);
 260
 261         local->hw_roc_channel = NULL;
 262         local->hw_roc_cookie = 0;
 263
 264         ieee80211_recalc_idle(local);
 265
 266         mutex_unlock(&local->mtx);
 267 }
 268
 269 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 270 {
 271         struct ieee80211_local *local = hw_to_local(hw);
 272
 273         trace_api_remain_on_channel_expired(local);
 274
 275         ieee80211_queue_work(hw, &local->hw_roc_done);
 276 }
 277 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 278
 279 void ieee80211_hw_roc_setup(struct ieee80211_local *local)
 280 {
 281         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 282         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 283 }