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