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-ops.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 {
  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 (!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_P2P_DEVICE)
 120                         continue;
 121
 122                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 123                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 124
 125                 /* Check to see if we should disable beaconing. */
 126                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 127                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 128                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 129                         ieee80211_bss_info_change_notify(
 130                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 131
 132                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 133                         netif_tx_stop_all_queues(sdata->dev);
 134                         if (offchannel_ps_enable &&
 135                             (sdata->vif.type == NL80211_IFTYPE_STATION) &&
 136                             sdata->u.mgd.associated)
 137                                 ieee80211_offchannel_ps_enable(sdata);
 138                 }
 139         }
 140         mutex_unlock(&local->iflist_mtx);
 141 }
 142
 143 void ieee80211_offchannel_return(struct ieee80211_local *local,
 144                                  bool offchannel_ps_disable)
 145 {
 146         struct ieee80211_sub_if_data *sdata;
 147
 148         mutex_lock(&local->iflist_mtx);
 149         list_for_each_entry(sdata, &local->interfaces, list) {
 150                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
 151                         continue;
 152
 153                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 154                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 155
 156                 if (!ieee80211_sdata_running(sdata))
 157                         continue;
 158
 159                 /* Tell AP we're back */
 160                 if (offchannel_ps_disable &&
 161                     sdata->vif.type == NL80211_IFTYPE_STATION) {
 162                         if (sdata->u.mgd.associated)
 163                                 ieee80211_offchannel_ps_disable(sdata);
 164                 }
 165
 166                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 167                         /*
 168                          * This may wake up queues even though the driver
 169                          * currently has them stopped. This is not very
 170                          * likely, since the driver won't have gotten any
 171                          * (or hardly any) new packets while we weren't
 172                          * on the right channel, and even if it happens
 173                          * it will at most lead to queueing up one more
 174                          * packet per queue in mac80211 rather than on
 175                          * the interface qdisc.
 176                          */
 177                         netif_tx_wake_all_queues(sdata->dev);
 178                 }
 179
 180                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 181                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 182                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 183                         ieee80211_bss_info_change_notify(
 184                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 185         }
 186         mutex_unlock(&local->iflist_mtx);
 187 }
 188
 189 void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc)
 190 {
 191         if (roc->notified)
 192                 return;
 193
 194         if (roc->mgmt_tx_cookie) {
 195                 if (!WARN_ON(!roc->frame)) {
 196                         ieee80211_tx_skb(roc->sdata, roc->frame);
 197                         roc->frame = NULL;
 198                 }
 199         } else {
 200                 cfg80211_ready_on_channel(&roc->sdata->wdev, (unsigned long)roc,
 201                                           roc->chan, roc->chan_type,
 202                                           roc->req_duration, GFP_KERNEL);
 203         }
 204
 205         roc->notified = true;
 206 }
 207
 208 static void ieee80211_hw_roc_start(struct work_struct *work)
 209 {
 210         struct ieee80211_local *local =
 211                 container_of(work, struct ieee80211_local, hw_roc_start);
 212         struct ieee80211_roc_work *roc, *dep, *tmp;
 213
 214         mutex_lock(&local->mtx);
 215
 216         if (list_empty(&local->roc_list))
 217                 goto out_unlock;
 218
 219         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 220                                list);
 221
 222         if (!roc->started)
 223                 goto out_unlock;
 224
 225         roc->hw_begun = true;
 226         roc->hw_start_time = local->hw_roc_start_time;
 227
 228         ieee80211_handle_roc_started(roc);
 229         list_for_each_entry_safe(dep, tmp, &roc->dependents, list) {
 230                 ieee80211_handle_roc_started(dep);
 231
 232                 if (dep->duration > roc->duration) {
 233                         u32 dur = dep->duration;
 234                         dep->duration = dur - roc->duration;
 235                         roc->duration = dur;
 236                         list_move(&dep->list, &roc->list);
 237                 }
 238         }
 239  out_unlock:
 240         mutex_unlock(&local->mtx);
 241 }
 242
 243 void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
 244 {
 245         struct ieee80211_local *local = hw_to_local(hw);
 246
 247         local->hw_roc_start_time = jiffies;
 248
 249         trace_api_ready_on_channel(local);
 250
 251         ieee80211_queue_work(hw, &local->hw_roc_start);
 252 }
 253 EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
 254
 255 void ieee80211_start_next_roc(struct ieee80211_local *local)
 256 {
 257         struct ieee80211_roc_work *roc;
 258
 259         lockdep_assert_held(&local->mtx);
 260
 261         if (list_empty(&local->roc_list)) {
 262                 ieee80211_run_deferred_scan(local);
 263                 return;
 264         }
 265
 266         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 267                                list);
 268
 269         if (WARN_ON_ONCE(roc->started))
 270                 return;
 271
 272         if (local->ops->remain_on_channel) {
 273                 int ret, duration = roc->duration;
 274
 275                 /* XXX: duplicated, see ieee80211_start_roc_work() */
 276                 if (!duration)
 277                         duration = 10;
 278
 279                 ret = drv_remain_on_channel(local, roc->chan,
 280                                             roc->chan_type,
 281                                             duration);
 282
 283                 roc->started = true;
 284
 285                 if (ret) {
 286                         wiphy_warn(local->hw.wiphy,
 287                                    "failed to start next HW ROC (%d)\n", ret);
 288                         /*
 289                          * queue the work struct again to avoid recursion
 290                          * when multiple failures occur
 291                          */
 292                         ieee80211_remain_on_channel_expired(&local->hw);
 293                 }
 294         } else {
 295                 /* delay it a bit */
 296                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 297                                              round_jiffies_relative(HZ/2));
 298         }
 299 }
 300
 301 void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc)
 302 {
 303         struct ieee80211_roc_work *dep, *tmp;
 304
 305         /* was never transmitted */
 306         if (roc->frame) {
 307                 cfg80211_mgmt_tx_status(&roc->sdata->wdev,
 308                                         (unsigned long)roc->frame,
 309                                         roc->frame->data, roc->frame->len,
 310                                         false, GFP_KERNEL);
 311                 kfree_skb(roc->frame);
 312         }
 313
 314         if (!roc->mgmt_tx_cookie)
 315                 cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
 316                                                    (unsigned long)roc,
 317                                                    roc->chan, roc->chan_type,
 318                                                    GFP_KERNEL);
 319
 320         list_for_each_entry_safe(dep, tmp, &roc->dependents, list)
 321                 ieee80211_roc_notify_destroy(dep);
 322
 323         kfree(roc);
 324 }
 325
 326 void ieee80211_sw_roc_work(struct work_struct *work)
 327 {
 328         struct ieee80211_roc_work *roc =
 329                 container_of(work, struct ieee80211_roc_work, work.work);
 330         struct ieee80211_sub_if_data *sdata = roc->sdata;
 331         struct ieee80211_local *local = sdata->local;
 332         bool started;
 333
 334         mutex_lock(&local->mtx);
 335
 336         if (roc->abort)
 337                 goto finish;
 338
 339         if (WARN_ON(list_empty(&local->roc_list)))
 340                 goto out_unlock;
 341
 342         if (WARN_ON(roc != list_first_entry(&local->roc_list,
 343                                             struct ieee80211_roc_work,
 344                                             list)))
 345                 goto out_unlock;
 346
 347         if (!roc->started) {
 348                 struct ieee80211_roc_work *dep;
 349
 350                 /* start this ROC */
 351
 352                 /* switch channel etc */
 353                 ieee80211_recalc_idle(local);
 354
 355                 local->tmp_channel = roc->chan;
 356                 local->tmp_channel_type = roc->chan_type;
 357                 ieee80211_hw_config(local, 0);
 358
 359                 /* tell userspace or send frame */
 360                 ieee80211_handle_roc_started(roc);
 361                 list_for_each_entry(dep, &roc->dependents, list)
 362                         ieee80211_handle_roc_started(dep);
 363
 364                 /* if it was pure TX, just finish right away */
 365                 if (!roc->duration)
 366                         goto finish;
 367
 368                 roc->started = true;
 369                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 370                                              msecs_to_jiffies(roc->duration));
 371         } else {
 372                 /* finish this ROC */
 373  finish:
 374                 list_del(&roc->list);
 375                 started = roc->started;
 376                 ieee80211_roc_notify_destroy(roc);
 377
 378                 if (started) {
 379                         drv_flush(local, false);
 380
 381                         local->tmp_channel = NULL;
 382                         ieee80211_hw_config(local, 0);
 383
 384                         ieee80211_offchannel_return(local, true);
 385                 }
 386
 387                 ieee80211_recalc_idle(local);
 388
 389                 if (started)
 390                         ieee80211_start_next_roc(local);
 391         }
 392
 393  out_unlock:
 394         mutex_unlock(&local->mtx);
 395 }
 396
 397 static void ieee80211_hw_roc_done(struct work_struct *work)
 398 {
 399         struct ieee80211_local *local =
 400                 container_of(work, struct ieee80211_local, hw_roc_done);
 401         struct ieee80211_roc_work *roc;
 402
 403         mutex_lock(&local->mtx);
 404
 405         if (list_empty(&local->roc_list))
 406                 goto out_unlock;
 407
 408         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 409                                list);
 410
 411         if (!roc->started)
 412                 goto out_unlock;
 413
 414         list_del(&roc->list);
 415
 416         ieee80211_roc_notify_destroy(roc);
 417
 418         /* if there's another roc, start it now */
 419         ieee80211_start_next_roc(local);
 420
 421  out_unlock:
 422         mutex_unlock(&local->mtx);
 423 }
 424
 425 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 426 {
 427         struct ieee80211_local *local = hw_to_local(hw);
 428
 429         trace_api_remain_on_channel_expired(local);
 430
 431         ieee80211_queue_work(hw, &local->hw_roc_done);
 432 }
 433 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 434
 435 void ieee80211_roc_setup(struct ieee80211_local *local)
 436 {
 437         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 438         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 439         INIT_LIST_HEAD(&local->roc_list);
 440 }
 441
 442 void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata)
 443 {
 444         struct ieee80211_local *local = sdata->local;
 445         struct ieee80211_roc_work *roc, *tmp;
 446         LIST_HEAD(tmp_list);
 447
 448         mutex_lock(&local->mtx);
 449         list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
 450                 if (roc->sdata != sdata)
 451                         continue;
 452
 453                 if (roc->started && local->ops->remain_on_channel) {
 454                         /* can race, so ignore return value */
 455                         drv_cancel_remain_on_channel(local);
 456                 }
 457
 458                 list_move_tail(&roc->list, &tmp_list);
 459                 roc->abort = true;
 460         }
 461         mutex_unlock(&local->mtx);
 462
 463         list_for_each_entry_safe(roc, tmp, &tmp_list, list) {
 464                 if (local->ops->remain_on_channel) {
 465                         list_del(&roc->list);
 466                         ieee80211_roc_notify_destroy(roc);
 467                 } else {
 468                         ieee80211_queue_delayed_work(&local->hw, &roc->work, 0);
 469
 470                         /* work will clean up etc */
 471                         flush_delayed_work(&roc->work);
 472                 }
 473         }
 474
 475         WARN_ON_ONCE(!list_empty(&tmp_list));
 476 }