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  * inform AP that we will go to sleep so that it will buffer the frames
  22  * while we scan
  23  */
  24 static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata)
  25 {
  26         struct ieee80211_local *local = sdata->local;
  27         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
  28
  29         local->offchannel_ps_enabled = false;
  30
  31         /* FIXME: what to do when local->pspolling is true? */
  32
  33         del_timer_sync(&local->dynamic_ps_timer);
  34         del_timer_sync(&ifmgd->bcn_mon_timer);
  35         del_timer_sync(&ifmgd->conn_mon_timer);
  36
  37         cancel_work_sync(&local->dynamic_ps_enable_work);
  38
  39         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
  40                 local->offchannel_ps_enabled = true;
  41                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
  42                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  43         }
  44
  45         if (!(local->offchannel_ps_enabled) ||
  46             !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
  47                 /*
  48                  * If power save was enabled, no need to send a nullfunc
  49                  * frame because AP knows that we are sleeping. But if the
  50                  * hardware is creating the nullfunc frame for power save
  51                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
  52                  * enabled) and power save was enabled, the firmware just
  53                  * sent a null frame with power save disabled. So we need
  54                  * to send a new nullfunc frame to inform the AP that we
  55                  * are again sleeping.
  56                  */
  57                 ieee80211_send_nullfunc(local, sdata, 1);
  58 }
  59
  60 /* inform AP that we are awake again, unless power save is enabled */
  61 static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
  62 {
  63         struct ieee80211_local *local = sdata->local;
  64
  65         if (!local->ps_sdata)
  66                 ieee80211_send_nullfunc(local, sdata, 0);
  67         else if (local->offchannel_ps_enabled) {
  68                 /*
  69                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
  70                  * will send a nullfunc frame with the powersave bit set
  71                  * even though the AP already knows that we are sleeping.
  72                  * This could be avoided by sending a null frame with power
  73                  * save bit disabled before enabling the power save, but
  74                  * this doesn't gain anything.
  75                  *
  76                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
  77                  * to send a nullfunc frame because AP already knows that
  78                  * we are sleeping, let's just enable power save mode in
  79                  * hardware.
  80                  */
  81                 local->hw.conf.flags |= IEEE80211_CONF_PS;
  82                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  83         } else if (local->hw.conf.dynamic_ps_timeout > 0) {
  84                 /*
  85                  * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
  86                  * had been running before leaving the operating channel,
  87                  * restart the timer now and send a nullfunc frame to inform
  88                  * the AP that we are awake.
  89                  */
  90                 ieee80211_send_nullfunc(local, sdata, 0);
  91                 mod_timer(&local->dynamic_ps_timer, jiffies +
  92                           msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
  93         }
  94
  95         ieee80211_sta_reset_beacon_monitor(sdata);
  96         ieee80211_sta_reset_conn_monitor(sdata);
  97 }
  98
  99 void ieee80211_offchannel_stop_beaconing(struct ieee80211_local *local)
 100 {
 101         struct ieee80211_sub_if_data *sdata;
 102
 103         mutex_lock(&local->iflist_mtx);
 104         list_for_each_entry(sdata, &local->interfaces, list) {
 105                 if (!ieee80211_sdata_running(sdata))
 106                         continue;
 107
 108                 /* disable beaconing */
 109                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 110                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 111                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 112                         ieee80211_bss_info_change_notify(
 113                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 114
 115                 /*
 116                  * only handle non-STA interfaces here, STA interfaces
 117                  * are handled in ieee80211_offchannel_stop_station(),
 118                  * e.g., from the background scan state machine.
 119                  *
 120                  * In addition, do not stop monitor interface to allow it to be
 121                  * used from user space controlled off-channel operations.
 122                  */
 123                 if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 124                     sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 125                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 126                         netif_tx_stop_all_queues(sdata->dev);
 127                 }
 128         }
 129         mutex_unlock(&local->iflist_mtx);
 130 }
 131
 132 void ieee80211_offchannel_stop_station(struct ieee80211_local *local)
 133 {
 134         struct ieee80211_sub_if_data *sdata;
 135
 136         /*
 137          * notify the AP about us leaving the channel and stop all STA interfaces
 138          */
 139         mutex_lock(&local->iflist_mtx);
 140         list_for_each_entry(sdata, &local->interfaces, list) {
 141                 if (!ieee80211_sdata_running(sdata))
 142                         continue;
 143
 144                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 145                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 146                         netif_tx_stop_all_queues(sdata->dev);
 147                         if (sdata->u.mgd.associated)
 148                                 ieee80211_offchannel_ps_enable(sdata);
 149                 }
 150         }
 151         mutex_unlock(&local->iflist_mtx);
 152 }
 153
 154 void ieee80211_offchannel_return(struct ieee80211_local *local,
 155                                  bool enable_beaconing)
 156 {
 157         struct ieee80211_sub_if_data *sdata;
 158
 159         mutex_lock(&local->iflist_mtx);
 160         list_for_each_entry(sdata, &local->interfaces, list) {
 161                 if (!ieee80211_sdata_running(sdata))
 162                         continue;
 163
 164                 /* Tell AP we're back */
 165                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 166                         if (sdata->u.mgd.associated)
 167                                 ieee80211_offchannel_ps_disable(sdata);
 168                 }
 169
 170                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 171                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 172                         /*
 173                          * This may wake up queues even though the driver
 174                          * currently has them stopped. This is not very
 175                          * likely, since the driver won't have gotten any
 176                          * (or hardly any) new packets while we weren't
 177                          * on the right channel, and even if it happens
 178                          * it will at most lead to queueing up one more
 179                          * packet per queue in mac80211 rather than on
 180                          * the interface qdisc.
 181                          */
 182                         netif_tx_wake_all_queues(sdata->dev);
 183                 }
 184
 185                 /* re-enable beaconing */
 186                 if (enable_beaconing &&
 187                     (sdata->vif.type == NL80211_IFTYPE_AP ||
 188                      sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 189                      sdata->vif.type == NL80211_IFTYPE_MESH_POINT))
 190                         ieee80211_bss_info_change_notify(
 191                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 192         }
 193         mutex_unlock(&local->iflist_mtx);
 194 }
 195
 196 static void ieee80211_hw_roc_start(struct work_struct *work)
 197 {
 198         struct ieee80211_local *local =
 199                 container_of(work, struct ieee80211_local, hw_roc_start);
 200         struct ieee80211_sub_if_data *sdata;
 201
 202         mutex_lock(&local->mtx);
 203
 204         if (!local->hw_roc_channel) {
 205                 mutex_unlock(&local->mtx);
 206                 return;
 207         }
 208
 209         ieee80211_recalc_idle(local);
 210
 211         if (local->hw_roc_skb) {
 212                 sdata = IEEE80211_DEV_TO_SUB_IF(local->hw_roc_dev);
 213                 ieee80211_tx_skb(sdata, local->hw_roc_skb);
 214                 local->hw_roc_skb = NULL;
 215         } else {
 216                 cfg80211_ready_on_channel(local->hw_roc_dev,
 217                                           local->hw_roc_cookie,
 218                                           local->hw_roc_channel,
 219                                           local->hw_roc_channel_type,
 220                                           local->hw_roc_duration,
 221                                           GFP_KERNEL);
 222         }
 223
 224         mutex_unlock(&local->mtx);
 225 }
 226
 227 void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
 228 {
 229         struct ieee80211_local *local = hw_to_local(hw);
 230
 231         trace_api_ready_on_channel(local);
 232
 233         ieee80211_queue_work(hw, &local->hw_roc_start);
 234 }
 235 EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
 236
 237 static void ieee80211_hw_roc_done(struct work_struct *work)
 238 {
 239         struct ieee80211_local *local =
 240                 container_of(work, struct ieee80211_local, hw_roc_done);
 241
 242         mutex_lock(&local->mtx);
 243
 244         if (!local->hw_roc_channel) {
 245                 mutex_unlock(&local->mtx);
 246                 return;
 247         }
 248
 249         if (!local->hw_roc_for_tx)
 250                 cfg80211_remain_on_channel_expired(local->hw_roc_dev,
 251                                                    local->hw_roc_cookie,
 252                                                    local->hw_roc_channel,
 253                                                    local->hw_roc_channel_type,
 254                                                    GFP_KERNEL);
 255
 256         local->hw_roc_channel = NULL;
 257         local->hw_roc_cookie = 0;
 258
 259         ieee80211_recalc_idle(local);
 260
 261         mutex_unlock(&local->mtx);
 262 }
 263
 264 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 265 {
 266         struct ieee80211_local *local = hw_to_local(hw);
 267
 268         trace_api_remain_on_channel_expired(local);
 269
 270         ieee80211_queue_work(hw, &local->hw_roc_done);
 271 }
 272 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 273
 274 void ieee80211_hw_roc_setup(struct ieee80211_local *local)
 275 {
 276         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 277         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 278 }