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 <linux/export.h>
  16 #include <net/mac80211.h>
  17 #include "ieee80211_i.h"
  18 #include "driver-trace.h"
  19
  20 /*
  21  * Tell our hardware to disable PS.
  22  * Optionally inform AP that we will go to sleep so that it will buffer
  23  * the frames while we are doing off-channel work.  This is optional
  24  * because we *may* be doing work on-operating channel, and want our
  25  * hardware unconditionally awake, but still let the AP send us normal frames.
  26  */
  27 static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata,
  28                                            bool tell_ap)
  29 {
  30         struct ieee80211_local *local = sdata->local;
  31         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
  32
  33         local->offchannel_ps_enabled = false;
  34
  35         /* FIXME: what to do when local->pspolling is true? */
  36
  37         del_timer_sync(&local->dynamic_ps_timer);
  38         del_timer_sync(&ifmgd->bcn_mon_timer);
  39         del_timer_sync(&ifmgd->conn_mon_timer);
  40
  41         cancel_work_sync(&local->dynamic_ps_enable_work);
  42
  43         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
  44                 local->offchannel_ps_enabled = true;
  45                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
  46                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  47         }
  48
  49         if (tell_ap && (!local->offchannel_ps_enabled ||
  50                         !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)))
  51                 /*
  52                  * If power save was enabled, no need to send a nullfunc
  53                  * frame because AP knows that we are sleeping. But if the
  54                  * hardware is creating the nullfunc frame for power save
  55                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
  56                  * enabled) and power save was enabled, the firmware just
  57                  * sent a null frame with power save disabled. So we need
  58                  * to send a new nullfunc frame to inform the AP that we
  59                  * are again sleeping.
  60                  */
  61                 ieee80211_send_nullfunc(local, sdata, 1);
  62 }
  63
  64 /* inform AP that we are awake again, unless power save is enabled */
  65 static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
  66 {
  67         struct ieee80211_local *local = sdata->local;
  68
  69         if (!local->ps_sdata)
  70                 ieee80211_send_nullfunc(local, sdata, 0);
  71         else if (local->offchannel_ps_enabled) {
  72                 /*
  73                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
  74                  * will send a nullfunc frame with the powersave bit set
  75                  * even though the AP already knows that we are sleeping.
  76                  * This could be avoided by sending a null frame with power
  77                  * save bit disabled before enabling the power save, but
  78                  * this doesn't gain anything.
  79                  *
  80                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
  81                  * to send a nullfunc frame because AP already knows that
  82                  * we are sleeping, let's just enable power save mode in
  83                  * hardware.
  84                  */
  85                 /* TODO:  Only set hardware if CONF_PS changed?
  86                  * TODO:  Should we set offchannel_ps_enabled to false?
  87                  */
  88                 local->hw.conf.flags |= IEEE80211_CONF_PS;
  89                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  90         } else if (local->hw.conf.dynamic_ps_timeout > 0) {
  91                 /*
  92                  * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
  93                  * had been running before leaving the operating channel,
  94                  * restart the timer now and send a nullfunc frame to inform
  95                  * the AP that we are awake.
  96                  */
  97                 ieee80211_send_nullfunc(local, sdata, 0);
  98                 mod_timer(&local->dynamic_ps_timer, jiffies +
  99                           msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
 100         }
 101
 102         ieee80211_sta_reset_beacon_monitor(sdata);
 103         ieee80211_sta_reset_conn_monitor(sdata);
 104 }
 105
 106 void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local,
 107                                     bool offchannel_ps_enable)
 108 {
 109         struct ieee80211_sub_if_data *sdata;
 110
 111         /*
 112          * notify the AP about us leaving the channel and stop all
 113          * STA interfaces.
 114          */
 115         mutex_lock(&local->iflist_mtx);
 116         list_for_each_entry(sdata, &local->interfaces, list) {
 117                 if (!ieee80211_sdata_running(sdata))
 118                         continue;
 119
 120                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 121                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 122
 123                 /* Check to see if we should disable beaconing. */
 124                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 125                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 126                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 127                         ieee80211_bss_info_change_notify(
 128                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 129
 130                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 131                         netif_tx_stop_all_queues(sdata->dev);
 132                         if (offchannel_ps_enable &&
 133                             (sdata->vif.type == NL80211_IFTYPE_STATION) &&
 134                             sdata->u.mgd.associated)
 135                                 ieee80211_offchannel_ps_enable(sdata, true);
 136                 }
 137         }
 138         mutex_unlock(&local->iflist_mtx);
 139 }
 140
 141 void ieee80211_offchannel_return(struct ieee80211_local *local,
 142                                  bool offchannel_ps_disable)
 143 {
 144         struct ieee80211_sub_if_data *sdata;
 145
 146         mutex_lock(&local->iflist_mtx);
 147         list_for_each_entry(sdata, &local->interfaces, list) {
 148                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 149                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 150
 151                 if (!ieee80211_sdata_running(sdata))
 152                         continue;
 153
 154                 /* Tell AP we're back */
 155                 if (offchannel_ps_disable &&
 156                     sdata->vif.type == NL80211_IFTYPE_STATION) {
 157                         if (sdata->u.mgd.associated)
 158                                 ieee80211_offchannel_ps_disable(sdata);
 159                 }
 160
 161                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 162                         /*
 163                          * This may wake up queues even though the driver
 164                          * currently has them stopped. This is not very
 165                          * likely, since the driver won't have gotten any
 166                          * (or hardly any) new packets while we weren't
 167                          * on the right channel, and even if it happens
 168                          * it will at most lead to queueing up one more
 169                          * packet per queue in mac80211 rather than on
 170                          * the interface qdisc.
 171                          */
 172                         netif_tx_wake_all_queues(sdata->dev);
 173                 }
 174
 175                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 176                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 177                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 178                         ieee80211_bss_info_change_notify(
 179                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 180         }
 181         mutex_unlock(&local->iflist_mtx);
 182 }
 183
 184 static void ieee80211_hw_roc_start(struct work_struct *work)
 185 {
 186         struct ieee80211_local *local =
 187                 container_of(work, struct ieee80211_local, hw_roc_start);
 188         struct ieee80211_sub_if_data *sdata;
 189
 190         mutex_lock(&local->mtx);
 191
 192         if (!local->hw_roc_channel) {
 193                 mutex_unlock(&local->mtx);
 194                 return;
 195         }
 196
 197         if (local->hw_roc_skb) {
 198                 sdata = IEEE80211_DEV_TO_SUB_IF(local->hw_roc_dev);
 199                 ieee80211_tx_skb(sdata, local->hw_roc_skb);
 200                 local->hw_roc_skb = NULL;
 201         } else {
 202                 cfg80211_ready_on_channel(local->hw_roc_dev,
 203                                           local->hw_roc_cookie,
 204                                           local->hw_roc_channel,
 205                                           local->hw_roc_channel_type,
 206                                           local->hw_roc_duration,
 207                                           GFP_KERNEL);
 208         }
 209
 210         ieee80211_recalc_idle(local);
 211
 212         mutex_unlock(&local->mtx);
 213 }
 214
 215 void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
 216 {
 217         struct ieee80211_local *local = hw_to_local(hw);
 218
 219         trace_api_ready_on_channel(local);
 220
 221         ieee80211_queue_work(hw, &local->hw_roc_start);
 222 }
 223 EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
 224
 225 static void ieee80211_hw_roc_done(struct work_struct *work)
 226 {
 227         struct ieee80211_local *local =
 228                 container_of(work, struct ieee80211_local, hw_roc_done);
 229
 230         mutex_lock(&local->mtx);
 231
 232         if (!local->hw_roc_channel) {
 233                 mutex_unlock(&local->mtx);
 234                 return;
 235         }
 236
 237         if (!local->hw_roc_for_tx)
 238                 cfg80211_remain_on_channel_expired(local->hw_roc_dev,
 239                                                    local->hw_roc_cookie,
 240                                                    local->hw_roc_channel,
 241                                                    local->hw_roc_channel_type,
 242                                                    GFP_KERNEL);
 243
 244         local->hw_roc_channel = NULL;
 245         local->hw_roc_cookie = 0;
 246
 247         ieee80211_recalc_idle(local);
 248
 249         mutex_unlock(&local->mtx);
 250 }
 251
 252 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 253 {
 254         struct ieee80211_local *local = hw_to_local(hw);
 255
 256         trace_api_remain_on_channel_expired(local);
 257
 258         ieee80211_queue_work(hw, &local->hw_roc_done);
 259 }
 260 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 261
 262 void ieee80211_hw_roc_setup(struct ieee80211_local *local)
 263 {
 264         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 265         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 266 }