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 {
 107         struct ieee80211_sub_if_data *sdata;
 108
 109         if (WARN_ON(local->use_chanctx))
 110                 return;
 111
 112         /*
 113          * notify the AP about us leaving the channel and stop all
 114          * STA interfaces.
 115          */
 116
 117         /*
 118          * Stop queues and transmit all frames queued by the driver
 119          * before sending nullfunc to enable powersave at the AP.
 120          */
 121         ieee80211_stop_queues_by_reason(&local->hw,
 122                                         IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL);
 123         drv_flush(local, false);
 124
 125         mutex_lock(&local->iflist_mtx);
 126         list_for_each_entry(sdata, &local->interfaces, list) {
 127                 if (!ieee80211_sdata_running(sdata))
 128                         continue;
 129
 130                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
 131                         continue;
 132
 133                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 134                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 135
 136                 /* Check to see if we should disable beaconing. */
 137                 if (sdata->vif.bss_conf.enable_beacon) {
 138                         set_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
 139                                 &sdata->state);
 140                         sdata->vif.bss_conf.enable_beacon = false;
 141                         ieee80211_bss_info_change_notify(
 142                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 143                 }
 144
 145                 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 146                     sdata->u.mgd.associated)
 147                         ieee80211_offchannel_ps_enable(sdata);
 148         }
 149         mutex_unlock(&local->iflist_mtx);
 150 }
 151
 152 void ieee80211_offchannel_return(struct ieee80211_local *local)
 153 {
 154         struct ieee80211_sub_if_data *sdata;
 155
 156         if (WARN_ON(local->use_chanctx))
 157                 return;
 158
 159         mutex_lock(&local->iflist_mtx);
 160         list_for_each_entry(sdata, &local->interfaces, list) {
 161                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
 162                         continue;
 163
 164                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 165                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 166
 167                 if (!ieee80211_sdata_running(sdata))
 168                         continue;
 169
 170                 /* Tell AP we're back */
 171                 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 172                     sdata->u.mgd.associated)
 173                         ieee80211_offchannel_ps_disable(sdata);
 174
 175                 if (test_and_clear_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
 176                                        &sdata->state)) {
 177                         sdata->vif.bss_conf.enable_beacon = true;
 178                         ieee80211_bss_info_change_notify(
 179                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 180                 }
 181         }
 182         mutex_unlock(&local->iflist_mtx);
 183
 184         ieee80211_wake_queues_by_reason(&local->hw,
 185                                         IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL);
 186 }
 187
 188 void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc)
 189 {
 190         if (roc->notified)
 191                 return;
 192
 193         if (roc->mgmt_tx_cookie) {
 194                 if (!WARN_ON(!roc->frame)) {
 195                         ieee80211_tx_skb_tid_band(roc->sdata, roc->frame, 7,
 196                                                   roc->chan->band);
 197                         roc->frame = NULL;
 198                 }
 199         } else {
 200                 cfg80211_ready_on_channel(&roc->sdata->wdev, roc->cookie,
 201                                           roc->chan, roc->req_duration,
 202                                           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->sdata, roc->chan,
 280                                             duration);
 281
 282                 roc->started = true;
 283
 284                 if (ret) {
 285                         wiphy_warn(local->hw.wiphy,
 286                                    "failed to start next HW ROC (%d)\n", ret);
 287                         /*
 288                          * queue the work struct again to avoid recursion
 289                          * when multiple failures occur
 290                          */
 291                         ieee80211_remain_on_channel_expired(&local->hw);
 292                 }
 293         } else {
 294                 /* delay it a bit */
 295                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 296                                              round_jiffies_relative(HZ/2));
 297         }
 298 }
 299
 300 void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc)
 301 {
 302         struct ieee80211_roc_work *dep, *tmp;
 303
 304         /* was never transmitted */
 305         if (roc->frame) {
 306                 cfg80211_mgmt_tx_status(&roc->sdata->wdev,
 307                                         (unsigned long)roc->frame,
 308                                         roc->frame->data, roc->frame->len,
 309                                         false, GFP_KERNEL);
 310                 kfree_skb(roc->frame);
 311         }
 312
 313         if (!roc->mgmt_tx_cookie)
 314                 cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
 315                                                    roc->cookie, roc->chan,
 316                                                    GFP_KERNEL);
 317
 318         list_for_each_entry_safe(dep, tmp, &roc->dependents, list)
 319                 ieee80211_roc_notify_destroy(dep);
 320
 321         kfree(roc);
 322 }
 323
 324 void ieee80211_sw_roc_work(struct work_struct *work)
 325 {
 326         struct ieee80211_roc_work *roc =
 327                 container_of(work, struct ieee80211_roc_work, work.work);
 328         struct ieee80211_sub_if_data *sdata = roc->sdata;
 329         struct ieee80211_local *local = sdata->local;
 330         bool started;
 331
 332         mutex_lock(&local->mtx);
 333
 334         if (roc->abort)
 335                 goto finish;
 336
 337         if (WARN_ON(list_empty(&local->roc_list)))
 338                 goto out_unlock;
 339
 340         if (WARN_ON(roc != list_first_entry(&local->roc_list,
 341                                             struct ieee80211_roc_work,
 342                                             list)))
 343                 goto out_unlock;
 344
 345         if (!roc->started) {
 346                 struct ieee80211_roc_work *dep;
 347
 348                 /* start this ROC */
 349
 350                 /* switch channel etc */
 351                 ieee80211_recalc_idle(local);
 352
 353                 local->tmp_channel = roc->chan;
 354                 ieee80211_hw_config(local, 0);
 355
 356                 /* tell userspace or send frame */
 357                 ieee80211_handle_roc_started(roc);
 358                 list_for_each_entry(dep, &roc->dependents, list)
 359                         ieee80211_handle_roc_started(dep);
 360
 361                 /* if it was pure TX, just finish right away */
 362                 if (!roc->duration)
 363                         goto finish;
 364
 365                 roc->started = true;
 366                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 367                                              msecs_to_jiffies(roc->duration));
 368         } else {
 369                 /* finish this ROC */
 370  finish:
 371                 list_del(&roc->list);
 372                 started = roc->started;
 373                 ieee80211_roc_notify_destroy(roc);
 374
 375                 if (started) {
 376                         drv_flush(local, false);
 377
 378                         local->tmp_channel = NULL;
 379                         ieee80211_hw_config(local, 0);
 380
 381                         ieee80211_offchannel_return(local);
 382                 }
 383
 384                 ieee80211_recalc_idle(local);
 385
 386                 if (started)
 387                         ieee80211_start_next_roc(local);
 388         }
 389
 390  out_unlock:
 391         mutex_unlock(&local->mtx);
 392 }
 393
 394 static void ieee80211_hw_roc_done(struct work_struct *work)
 395 {
 396         struct ieee80211_local *local =
 397                 container_of(work, struct ieee80211_local, hw_roc_done);
 398         struct ieee80211_roc_work *roc;
 399
 400         mutex_lock(&local->mtx);
 401
 402         if (list_empty(&local->roc_list))
 403                 goto out_unlock;
 404
 405         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 406                                list);
 407
 408         if (!roc->started)
 409                 goto out_unlock;
 410
 411         list_del(&roc->list);
 412
 413         ieee80211_roc_notify_destroy(roc);
 414
 415         /* if there's another roc, start it now */
 416         ieee80211_start_next_roc(local);
 417
 418  out_unlock:
 419         mutex_unlock(&local->mtx);
 420 }
 421
 422 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 423 {
 424         struct ieee80211_local *local = hw_to_local(hw);
 425
 426         trace_api_remain_on_channel_expired(local);
 427
 428         ieee80211_queue_work(hw, &local->hw_roc_done);
 429 }
 430 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 431
 432 void ieee80211_roc_setup(struct ieee80211_local *local)
 433 {
 434         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 435         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 436         INIT_LIST_HEAD(&local->roc_list);
 437 }
 438
 439 void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata)
 440 {
 441         struct ieee80211_local *local = sdata->local;
 442         struct ieee80211_roc_work *roc, *tmp;
 443         LIST_HEAD(tmp_list);
 444
 445         mutex_lock(&local->mtx);
 446         list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
 447                 if (roc->sdata != sdata)
 448                         continue;
 449
 450                 if (roc->started && local->ops->remain_on_channel) {
 451                         /* can race, so ignore return value */
 452                         drv_cancel_remain_on_channel(local);
 453                 }
 454
 455                 list_move_tail(&roc->list, &tmp_list);
 456                 roc->abort = true;
 457         }
 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 }