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         if (WARN_ON(local->use_chanctx))
 111                 return;
 112
 113         /*
 114          * notify the AP about us leaving the channel and stop all
 115          * STA interfaces.
 116          */
 117         mutex_lock(&local->iflist_mtx);
 118         list_for_each_entry(sdata, &local->interfaces, list) {
 119                 if (!ieee80211_sdata_running(sdata))
 120                         continue;
 121
 122                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
 123                         continue;
 124
 125                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 126                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 127
 128                 /* Check to see if we should disable beaconing. */
 129                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 130                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 131                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 132                         ieee80211_bss_info_change_notify(
 133                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 134
 135                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 136                         netif_tx_stop_all_queues(sdata->dev);
 137                         if (offchannel_ps_enable &&
 138                             (sdata->vif.type == NL80211_IFTYPE_STATION) &&
 139                             sdata->u.mgd.associated)
 140                                 ieee80211_offchannel_ps_enable(sdata);
 141                 }
 142         }
 143         mutex_unlock(&local->iflist_mtx);
 144 }
 145
 146 void ieee80211_offchannel_return(struct ieee80211_local *local,
 147                                  bool offchannel_ps_disable)
 148 {
 149         struct ieee80211_sub_if_data *sdata;
 150
 151         if (WARN_ON(local->use_chanctx))
 152                 return;
 153
 154         mutex_lock(&local->iflist_mtx);
 155         list_for_each_entry(sdata, &local->interfaces, list) {
 156                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
 157                         continue;
 158
 159                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 160                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 161
 162                 if (!ieee80211_sdata_running(sdata))
 163                         continue;
 164
 165                 /* Tell AP we're back */
 166                 if (offchannel_ps_disable &&
 167                     sdata->vif.type == NL80211_IFTYPE_STATION) {
 168                         if (sdata->u.mgd.associated)
 169                                 ieee80211_offchannel_ps_disable(sdata);
 170                 }
 171
 172                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 173                         /*
 174                          * This may wake up queues even though the driver
 175                          * currently has them stopped. This is not very
 176                          * likely, since the driver won't have gotten any
 177                          * (or hardly any) new packets while we weren't
 178                          * on the right channel, and even if it happens
 179                          * it will at most lead to queueing up one more
 180                          * packet per queue in mac80211 rather than on
 181                          * the interface qdisc.
 182                          */
 183                         netif_tx_wake_all_queues(sdata->dev);
 184                 }
 185
 186                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 187                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 188                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 189                         ieee80211_bss_info_change_notify(
 190                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 191         }
 192         mutex_unlock(&local->iflist_mtx);
 193 }
 194
 195 void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc)
 196 {
 197         if (roc->notified)
 198                 return;
 199
 200         if (roc->mgmt_tx_cookie) {
 201                 if (!WARN_ON(!roc->frame)) {
 202                         ieee80211_tx_skb_tid_band(roc->sdata, roc->frame, 7,
 203                                                   roc->chan->band);
 204                         roc->frame = NULL;
 205                 }
 206         } else {
 207                 cfg80211_ready_on_channel(&roc->sdata->wdev, roc->cookie,
 208                                           roc->chan, roc->req_duration,
 209                                           GFP_KERNEL);
 210         }
 211
 212         roc->notified = true;
 213 }
 214
 215 static void ieee80211_hw_roc_start(struct work_struct *work)
 216 {
 217         struct ieee80211_local *local =
 218                 container_of(work, struct ieee80211_local, hw_roc_start);
 219         struct ieee80211_roc_work *roc, *dep, *tmp;
 220
 221         mutex_lock(&local->mtx);
 222
 223         if (list_empty(&local->roc_list))
 224                 goto out_unlock;
 225
 226         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 227                                list);
 228
 229         if (!roc->started)
 230                 goto out_unlock;
 231
 232         roc->hw_begun = true;
 233         roc->hw_start_time = local->hw_roc_start_time;
 234
 235         ieee80211_handle_roc_started(roc);
 236         list_for_each_entry_safe(dep, tmp, &roc->dependents, list) {
 237                 ieee80211_handle_roc_started(dep);
 238
 239                 if (dep->duration > roc->duration) {
 240                         u32 dur = dep->duration;
 241                         dep->duration = dur - roc->duration;
 242                         roc->duration = dur;
 243                         list_move(&dep->list, &roc->list);
 244                 }
 245         }
 246  out_unlock:
 247         mutex_unlock(&local->mtx);
 248 }
 249
 250 void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
 251 {
 252         struct ieee80211_local *local = hw_to_local(hw);
 253
 254         local->hw_roc_start_time = jiffies;
 255
 256         trace_api_ready_on_channel(local);
 257
 258         ieee80211_queue_work(hw, &local->hw_roc_start);
 259 }
 260 EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
 261
 262 void ieee80211_start_next_roc(struct ieee80211_local *local)
 263 {
 264         struct ieee80211_roc_work *roc;
 265
 266         lockdep_assert_held(&local->mtx);
 267
 268         if (list_empty(&local->roc_list)) {
 269                 ieee80211_run_deferred_scan(local);
 270                 return;
 271         }
 272
 273         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 274                                list);
 275
 276         if (WARN_ON_ONCE(roc->started))
 277                 return;
 278
 279         if (local->ops->remain_on_channel) {
 280                 int ret, duration = roc->duration;
 281
 282                 /* XXX: duplicated, see ieee80211_start_roc_work() */
 283                 if (!duration)
 284                         duration = 10;
 285
 286                 ret = drv_remain_on_channel(local, roc->sdata, roc->chan,
 287                                             duration);
 288
 289                 roc->started = true;
 290
 291                 if (ret) {
 292                         wiphy_warn(local->hw.wiphy,
 293                                    "failed to start next HW ROC (%d)\n", ret);
 294                         /*
 295                          * queue the work struct again to avoid recursion
 296                          * when multiple failures occur
 297                          */
 298                         ieee80211_remain_on_channel_expired(&local->hw);
 299                 }
 300         } else {
 301                 /* delay it a bit */
 302                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 303                                              round_jiffies_relative(HZ/2));
 304         }
 305 }
 306
 307 void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc)
 308 {
 309         struct ieee80211_roc_work *dep, *tmp;
 310
 311         /* was never transmitted */
 312         if (roc->frame) {
 313                 cfg80211_mgmt_tx_status(&roc->sdata->wdev,
 314                                         (unsigned long)roc->frame,
 315                                         roc->frame->data, roc->frame->len,
 316                                         false, GFP_KERNEL);
 317                 kfree_skb(roc->frame);
 318         }
 319
 320         if (!roc->mgmt_tx_cookie)
 321                 cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
 322                                                    roc->cookie, roc->chan,
 323                                                    GFP_KERNEL);
 324
 325         list_for_each_entry_safe(dep, tmp, &roc->dependents, list)
 326                 ieee80211_roc_notify_destroy(dep);
 327
 328         kfree(roc);
 329 }
 330
 331 void ieee80211_sw_roc_work(struct work_struct *work)
 332 {
 333         struct ieee80211_roc_work *roc =
 334                 container_of(work, struct ieee80211_roc_work, work.work);
 335         struct ieee80211_sub_if_data *sdata = roc->sdata;
 336         struct ieee80211_local *local = sdata->local;
 337         bool started;
 338
 339         mutex_lock(&local->mtx);
 340
 341         if (roc->abort)
 342                 goto finish;
 343
 344         if (WARN_ON(list_empty(&local->roc_list)))
 345                 goto out_unlock;
 346
 347         if (WARN_ON(roc != list_first_entry(&local->roc_list,
 348                                             struct ieee80211_roc_work,
 349                                             list)))
 350                 goto out_unlock;
 351
 352         if (!roc->started) {
 353                 struct ieee80211_roc_work *dep;
 354
 355                 /* start this ROC */
 356
 357                 /* switch channel etc */
 358                 ieee80211_recalc_idle(local);
 359
 360                 local->tmp_channel = roc->chan;
 361                 ieee80211_hw_config(local, 0);
 362
 363                 /* tell userspace or send frame */
 364                 ieee80211_handle_roc_started(roc);
 365                 list_for_each_entry(dep, &roc->dependents, list)
 366                         ieee80211_handle_roc_started(dep);
 367
 368                 /* if it was pure TX, just finish right away */
 369                 if (!roc->duration)
 370                         goto finish;
 371
 372                 roc->started = true;
 373                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 374                                              msecs_to_jiffies(roc->duration));
 375         } else {
 376                 /* finish this ROC */
 377  finish:
 378                 list_del(&roc->list);
 379                 started = roc->started;
 380                 ieee80211_roc_notify_destroy(roc);
 381
 382                 if (started) {
 383                         drv_flush(local, false);
 384
 385                         local->tmp_channel = NULL;
 386                         ieee80211_hw_config(local, 0);
 387
 388                         ieee80211_offchannel_return(local, true);
 389                 }
 390
 391                 ieee80211_recalc_idle(local);
 392
 393                 if (started)
 394                         ieee80211_start_next_roc(local);
 395         }
 396
 397  out_unlock:
 398         mutex_unlock(&local->mtx);
 399 }
 400
 401 static void ieee80211_hw_roc_done(struct work_struct *work)
 402 {
 403         struct ieee80211_local *local =
 404                 container_of(work, struct ieee80211_local, hw_roc_done);
 405         struct ieee80211_roc_work *roc;
 406
 407         mutex_lock(&local->mtx);
 408
 409         if (list_empty(&local->roc_list))
 410                 goto out_unlock;
 411
 412         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 413                                list);
 414
 415         if (!roc->started)
 416                 goto out_unlock;
 417
 418         list_del(&roc->list);
 419
 420         ieee80211_roc_notify_destroy(roc);
 421
 422         /* if there's another roc, start it now */
 423         ieee80211_start_next_roc(local);
 424
 425  out_unlock:
 426         mutex_unlock(&local->mtx);
 427 }
 428
 429 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 430 {
 431         struct ieee80211_local *local = hw_to_local(hw);
 432
 433         trace_api_remain_on_channel_expired(local);
 434
 435         ieee80211_queue_work(hw, &local->hw_roc_done);
 436 }
 437 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 438
 439 void ieee80211_roc_setup(struct ieee80211_local *local)
 440 {
 441         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 442         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 443         INIT_LIST_HEAD(&local->roc_list);
 444 }
 445
 446 void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata)
 447 {
 448         struct ieee80211_local *local = sdata->local;
 449         struct ieee80211_roc_work *roc, *tmp;
 450         LIST_HEAD(tmp_list);
 451
 452         mutex_lock(&local->mtx);
 453         list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
 454                 if (roc->sdata != sdata)
 455                         continue;
 456
 457                 if (roc->started && local->ops->remain_on_channel) {
 458                         /* can race, so ignore return value */
 459                         drv_cancel_remain_on_channel(local);
 460                 }
 461
 462                 list_move_tail(&roc->list, &tmp_list);
 463                 roc->abort = true;
 464         }
 465         mutex_unlock(&local->mtx);
 466
 467         list_for_each_entry_safe(roc, tmp, &tmp_list, list) {
 468                 if (local->ops->remain_on_channel) {
 469                         list_del(&roc->list);
 470                         ieee80211_roc_notify_destroy(roc);
 471                 } else {
 472                         ieee80211_queue_delayed_work(&local->hw, &roc->work, 0);
 473
 474                         /* work will clean up etc */
 475                         flush_delayed_work(&roc->work);
 476                 }
 477         }
 478
 479         WARN_ON_ONCE(!list_empty(&tmp_list));
 480 }