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 #include "driver-ops.h"
  20
  21 /*
  22  * Tell our hardware to disable PS.
  23  * Optionally inform AP that we will go to sleep so that it will buffer
  24  * the frames while we are doing off-channel work.  This is optional
  25  * because we *may* be doing work on-operating channel, and want our
  26  * hardware unconditionally awake, but still let the AP send us normal frames.
  27  */
  28 static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata)
  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 (!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);
 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 void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc)
 185 {
 186         if (roc->notified)
 187                 return;
 188
 189         if (roc->mgmt_tx_cookie) {
 190                 if (!WARN_ON(!roc->frame)) {
 191                         ieee80211_tx_skb(roc->sdata, roc->frame);
 192                         roc->frame = NULL;
 193                 }
 194         } else {
 195                 cfg80211_ready_on_channel(roc->sdata->dev, (unsigned long)roc,
 196                                           roc->chan, roc->chan_type,
 197                                           roc->req_duration, GFP_KERNEL);
 198         }
 199
 200         roc->notified = true;
 201 }
 202
 203 static void ieee80211_hw_roc_start(struct work_struct *work)
 204 {
 205         struct ieee80211_local *local =
 206                 container_of(work, struct ieee80211_local, hw_roc_start);
 207         struct ieee80211_roc_work *roc, *dep, *tmp;
 208
 209         mutex_lock(&local->mtx);
 210
 211         if (list_empty(&local->roc_list))
 212                 goto out_unlock;
 213
 214         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 215                                list);
 216
 217         if (!roc->started)
 218                 goto out_unlock;
 219
 220         roc->hw_begun = true;
 221         roc->hw_start_time = local->hw_roc_start_time;
 222
 223         ieee80211_handle_roc_started(roc);
 224         list_for_each_entry_safe(dep, tmp, &roc->dependents, list) {
 225                 ieee80211_handle_roc_started(dep);
 226
 227                 if (dep->duration > roc->duration) {
 228                         u32 dur = dep->duration;
 229                         dep->duration = dur - roc->duration;
 230                         roc->duration = dur;
 231                         list_del(&dep->list);
 232                         list_add(&dep->list, &roc->list);
 233                 }
 234         }
 235  out_unlock:
 236         mutex_unlock(&local->mtx);
 237 }
 238
 239 void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
 240 {
 241         struct ieee80211_local *local = hw_to_local(hw);
 242
 243         local->hw_roc_start_time = jiffies;
 244
 245         trace_api_ready_on_channel(local);
 246
 247         ieee80211_queue_work(hw, &local->hw_roc_start);
 248 }
 249 EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
 250
 251 void ieee80211_start_next_roc(struct ieee80211_local *local)
 252 {
 253         struct ieee80211_roc_work *roc;
 254
 255         lockdep_assert_held(&local->mtx);
 256
 257         if (list_empty(&local->roc_list)) {
 258                 ieee80211_run_deferred_scan(local);
 259                 return;
 260         }
 261
 262         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 263                                list);
 264
 265         if (WARN_ON_ONCE(roc->started))
 266                 return;
 267
 268         if (local->ops->remain_on_channel) {
 269                 int ret, duration = roc->duration;
 270
 271                 /* XXX: duplicated, see ieee80211_start_roc_work() */
 272                 if (!duration)
 273                         duration = 10;
 274
 275                 ret = drv_remain_on_channel(local, roc->chan,
 276                                             roc->chan_type,
 277                                             duration);
 278
 279                 roc->started = true;
 280
 281                 if (ret) {
 282                         wiphy_warn(local->hw.wiphy,
 283                                    "failed to start next HW ROC (%d)\n", ret);
 284                         /*
 285                          * queue the work struct again to avoid recursion
 286                          * when multiple failures occur
 287                          */
 288                         ieee80211_remain_on_channel_expired(&local->hw);
 289                 }
 290         } else {
 291                 /* delay it a bit */
 292                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 293                                              round_jiffies_relative(HZ/2));
 294         }
 295 }
 296
 297 void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc)
 298 {
 299         struct ieee80211_roc_work *dep, *tmp;
 300
 301         /* was never transmitted */
 302         if (roc->frame) {
 303                 cfg80211_mgmt_tx_status(roc->sdata->dev,
 304                                         (unsigned long)roc->frame,
 305                                         roc->frame->data, roc->frame->len,
 306                                         false, GFP_KERNEL);
 307                 kfree_skb(roc->frame);
 308         }
 309
 310         if (!roc->mgmt_tx_cookie)
 311                 cfg80211_remain_on_channel_expired(roc->sdata->dev,
 312                                                    (unsigned long)roc,
 313                                                    roc->chan, roc->chan_type,
 314                                                    GFP_KERNEL);
 315
 316         list_for_each_entry_safe(dep, tmp, &roc->dependents, list)
 317                 ieee80211_roc_notify_destroy(dep);
 318
 319         kfree(roc);
 320 }
 321
 322 void ieee80211_sw_roc_work(struct work_struct *work)
 323 {
 324         struct ieee80211_roc_work *roc =
 325                 container_of(work, struct ieee80211_roc_work, work.work);
 326         struct ieee80211_sub_if_data *sdata = roc->sdata;
 327         struct ieee80211_local *local = sdata->local;
 328
 329         mutex_lock(&local->mtx);
 330
 331         if (roc->abort)
 332                 goto finish;
 333
 334         if (WARN_ON(list_empty(&local->roc_list)))
 335                 goto out_unlock;
 336
 337         if (WARN_ON(roc != list_first_entry(&local->roc_list,
 338                                             struct ieee80211_roc_work,
 339                                             list)))
 340                 goto out_unlock;
 341
 342         if (!roc->started) {
 343                 struct ieee80211_roc_work *dep;
 344
 345                 /* start this ROC */
 346
 347                 /* switch channel etc */
 348                 ieee80211_recalc_idle(local);
 349
 350                 local->tmp_channel = roc->chan;
 351                 local->tmp_channel_type = roc->chan_type;
 352                 ieee80211_hw_config(local, 0);
 353
 354                 /* tell userspace or send frame */
 355                 ieee80211_handle_roc_started(roc);
 356                 list_for_each_entry(dep, &roc->dependents, list)
 357                         ieee80211_handle_roc_started(dep);
 358
 359                 /* if it was pure TX, just finish right away */
 360                 if (!roc->duration)
 361                         goto finish;
 362
 363                 roc->started = true;
 364                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 365                                              msecs_to_jiffies(roc->duration));
 366         } else {
 367                 /* finish this ROC */
 368  finish:
 369                 list_del(&roc->list);
 370                 ieee80211_roc_notify_destroy(roc);
 371
 372                 if (roc->started) {
 373                         drv_flush(local, false);
 374
 375                         local->tmp_channel = NULL;
 376                         ieee80211_hw_config(local, 0);
 377
 378                         ieee80211_offchannel_return(local, true);
 379                 }
 380
 381                 ieee80211_recalc_idle(local);
 382
 383                 if (roc->started)
 384                         ieee80211_start_next_roc(local);
 385         }
 386
 387  out_unlock:
 388         mutex_unlock(&local->mtx);
 389 }
 390
 391 static void ieee80211_hw_roc_done(struct work_struct *work)
 392 {
 393         struct ieee80211_local *local =
 394                 container_of(work, struct ieee80211_local, hw_roc_done);
 395         struct ieee80211_roc_work *roc;
 396
 397         mutex_lock(&local->mtx);
 398
 399         if (list_empty(&local->roc_list))
 400                 goto out_unlock;
 401
 402         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 403                                list);
 404
 405         if (!roc->started)
 406                 goto out_unlock;
 407
 408         list_del(&roc->list);
 409
 410         ieee80211_roc_notify_destroy(roc);
 411
 412         /* if there's another roc, start it now */
 413         ieee80211_start_next_roc(local);
 414
 415  out_unlock:
 416         mutex_unlock(&local->mtx);
 417 }
 418
 419 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 420 {
 421         struct ieee80211_local *local = hw_to_local(hw);
 422
 423         trace_api_remain_on_channel_expired(local);
 424
 425         ieee80211_queue_work(hw, &local->hw_roc_done);
 426 }
 427 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 428
 429 void ieee80211_roc_setup(struct ieee80211_local *local)
 430 {
 431         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 432         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 433         INIT_LIST_HEAD(&local->roc_list);
 434 }
 435
 436 void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata)
 437 {
 438         struct ieee80211_local *local = sdata->local;
 439         struct ieee80211_roc_work *roc, *tmp;
 440         LIST_HEAD(tmp_list);
 441
 442         mutex_lock(&local->mtx);
 443         list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
 444                 if (roc->sdata != sdata)
 445                         continue;
 446
 447                 if (roc->started && local->ops->remain_on_channel) {
 448                         /* can race, so ignore return value */
 449                         drv_cancel_remain_on_channel(local);
 450                 }
 451
 452                 list_move_tail(&roc->list, &tmp_list);
 453                 roc->abort = true;
 454         }
 455
 456         ieee80211_start_next_roc(local);
 457         mutex_unlock(&local->mtx);
 458
 459         list_for_each_entry_safe(roc, tmp, &tmp_list, list) {
 460                 if (local->ops->remain_on_channel) {
 461                         list_del(&roc->list);
 462                         ieee80211_roc_notify_destroy(roc);
 463                 } else {
 464                         ieee80211_queue_delayed_work(&local->hw, &roc->work, 0);
 465
 466                         /* work will clean up etc */
 467                         flush_delayed_work(&roc->work);
 468                 }
 469         }
 470
 471         WARN_ON_ONCE(!list_empty(&tmp_list));
 472 }