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, IEEE80211_MAX_QUEUE_MAP,
 122                                         IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL,
 123                                         false);
 124         ieee80211_flush_queues(local, NULL);
 125
 126         mutex_lock(&local->iflist_mtx);
 127         list_for_each_entry(sdata, &local->interfaces, list) {
 128                 if (!ieee80211_sdata_running(sdata))
 129                         continue;
 130
 131                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
 132                         continue;
 133
 134                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 135                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 136
 137                 /* Check to see if we should disable beaconing. */
 138                 if (sdata->vif.bss_conf.enable_beacon) {
 139                         set_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
 140                                 &sdata->state);
 141                         sdata->vif.bss_conf.enable_beacon = false;
 142                         ieee80211_bss_info_change_notify(
 143                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 144                 }
 145
 146                 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 147                     sdata->u.mgd.associated)
 148                         ieee80211_offchannel_ps_enable(sdata);
 149         }
 150         mutex_unlock(&local->iflist_mtx);
 151 }
 152
 153 void ieee80211_offchannel_return(struct ieee80211_local *local)
 154 {
 155         struct ieee80211_sub_if_data *sdata;
 156
 157         if (WARN_ON(local->use_chanctx))
 158                 return;
 159
 160         mutex_lock(&local->iflist_mtx);
 161         list_for_each_entry(sdata, &local->interfaces, list) {
 162                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
 163                         continue;
 164
 165                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 166                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 167
 168                 if (!ieee80211_sdata_running(sdata))
 169                         continue;
 170
 171                 /* Tell AP we're back */
 172                 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 173                     sdata->u.mgd.associated)
 174                         ieee80211_offchannel_ps_disable(sdata);
 175
 176                 if (test_and_clear_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
 177                                        &sdata->state)) {
 178                         sdata->vif.bss_conf.enable_beacon = true;
 179                         ieee80211_bss_info_change_notify(
 180                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 181                 }
 182         }
 183         mutex_unlock(&local->iflist_mtx);
 184
 185         ieee80211_wake_queues_by_reason(&local->hw, IEEE80211_MAX_QUEUE_MAP,
 186                                         IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL,
 187                                         false);
 188 }
 189
 190 void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc)
 191 {
 192         if (roc->notified)
 193                 return;
 194
 195         if (roc->mgmt_tx_cookie) {
 196                 if (!WARN_ON(!roc->frame)) {
 197                         ieee80211_tx_skb_tid_band(roc->sdata, roc->frame, 7,
 198                                                   roc->chan->band);
 199                         roc->frame = NULL;
 200                 }
 201         } else {
 202                 cfg80211_ready_on_channel(&roc->sdata->wdev, roc->cookie,
 203                                           roc->chan, roc->req_duration,
 204                                           GFP_KERNEL);
 205         }
 206
 207         roc->notified = true;
 208 }
 209
 210 static void ieee80211_hw_roc_start(struct work_struct *work)
 211 {
 212         struct ieee80211_local *local =
 213                 container_of(work, struct ieee80211_local, hw_roc_start);
 214         struct ieee80211_roc_work *roc, *dep, *tmp;
 215
 216         mutex_lock(&local->mtx);
 217
 218         if (list_empty(&local->roc_list))
 219                 goto out_unlock;
 220
 221         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 222                                list);
 223
 224         if (!roc->started)
 225                 goto out_unlock;
 226
 227         roc->hw_begun = true;
 228         roc->hw_start_time = local->hw_roc_start_time;
 229
 230         ieee80211_handle_roc_started(roc);
 231         list_for_each_entry_safe(dep, tmp, &roc->dependents, list) {
 232                 ieee80211_handle_roc_started(dep);
 233
 234                 if (dep->duration > roc->duration) {
 235                         u32 dur = dep->duration;
 236                         dep->duration = dur - roc->duration;
 237                         roc->duration = dur;
 238                         list_move(&dep->list, &roc->list);
 239                 }
 240         }
 241  out_unlock:
 242         mutex_unlock(&local->mtx);
 243 }
 244
 245 void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
 246 {
 247         struct ieee80211_local *local = hw_to_local(hw);
 248
 249         local->hw_roc_start_time = jiffies;
 250
 251         trace_api_ready_on_channel(local);
 252
 253         ieee80211_queue_work(hw, &local->hw_roc_start);
 254 }
 255 EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
 256
 257 void ieee80211_start_next_roc(struct ieee80211_local *local)
 258 {
 259         struct ieee80211_roc_work *roc;
 260
 261         lockdep_assert_held(&local->mtx);
 262
 263         if (list_empty(&local->roc_list)) {
 264                 ieee80211_run_deferred_scan(local);
 265                 return;
 266         }
 267
 268         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 269                                list);
 270
 271         if (WARN_ON_ONCE(roc->started))
 272                 return;
 273
 274         if (local->ops->remain_on_channel) {
 275                 int ret, duration = roc->duration;
 276
 277                 /* XXX: duplicated, see ieee80211_start_roc_work() */
 278                 if (!duration)
 279                         duration = 10;
 280
 281                 ret = drv_remain_on_channel(local, roc->sdata, roc->chan,
 282                                             duration, roc->type);
 283
 284                 roc->started = true;
 285
 286                 if (ret) {
 287                         wiphy_warn(local->hw.wiphy,
 288                                    "failed to start next HW ROC (%d)\n", ret);
 289                         /*
 290                          * queue the work struct again to avoid recursion
 291                          * when multiple failures occur
 292                          */
 293                         ieee80211_remain_on_channel_expired(&local->hw);
 294                 }
 295         } else {
 296                 /* delay it a bit */
 297                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 298                                              round_jiffies_relative(HZ/2));
 299         }
 300 }
 301
 302 void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc, bool free)
 303 {
 304         struct ieee80211_roc_work *dep, *tmp;
 305
 306         if (WARN_ON(roc->to_be_freed))
 307                 return;
 308
 309         /* was never transmitted */
 310         if (roc->frame) {
 311                 cfg80211_mgmt_tx_status(&roc->sdata->wdev,
 312                                         (unsigned long)roc->frame,
 313                                         roc->frame->data, roc->frame->len,
 314                                         false, GFP_KERNEL);
 315                 kfree_skb(roc->frame);
 316         }
 317
 318         if (!roc->mgmt_tx_cookie)
 319                 cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
 320                                                    roc->cookie, roc->chan,
 321                                                    GFP_KERNEL);
 322
 323         list_for_each_entry_safe(dep, tmp, &roc->dependents, list)
 324                 ieee80211_roc_notify_destroy(dep, true);
 325
 326         if (free)
 327                 kfree(roc);
 328         else
 329                 roc->to_be_freed = true;
 330 }
 331
 332 void ieee80211_sw_roc_work(struct work_struct *work)
 333 {
 334         struct ieee80211_roc_work *roc =
 335                 container_of(work, struct ieee80211_roc_work, work.work);
 336         struct ieee80211_sub_if_data *sdata = roc->sdata;
 337         struct ieee80211_local *local = sdata->local;
 338         bool started, on_channel;
 339
 340         mutex_lock(&local->mtx);
 341
 342         if (roc->to_be_freed)
 343                 goto out_unlock;
 344
 345         if (roc->abort)
 346                 goto finish;
 347
 348         if (WARN_ON(list_empty(&local->roc_list)))
 349                 goto out_unlock;
 350
 351         if (WARN_ON(roc != list_first_entry(&local->roc_list,
 352                                             struct ieee80211_roc_work,
 353                                             list)))
 354                 goto out_unlock;
 355
 356         if (!roc->started) {
 357                 struct ieee80211_roc_work *dep;
 358
 359                 WARN_ON(local->use_chanctx);
 360
 361                 /* If actually operating on the desired channel (with at least
 362                  * 20 MHz channel width) don't stop all the operations but still
 363                  * treat it as though the ROC operation started properly, so
 364                  * other ROC operations won't interfere with this one.
 365                  */
 366                 roc->on_channel = roc->chan == local->_oper_chandef.chan &&
 367                                   local->_oper_chandef.width != NL80211_CHAN_WIDTH_5 &&
 368                                   local->_oper_chandef.width != NL80211_CHAN_WIDTH_10;
 369
 370                 /* start this ROC */
 371                 ieee80211_recalc_idle(local);
 372
 373                 if (!roc->on_channel) {
 374                         ieee80211_offchannel_stop_vifs(local);
 375
 376                         local->tmp_channel = roc->chan;
 377                         ieee80211_hw_config(local, 0);
 378                 }
 379
 380                 /* tell userspace or send frame */
 381                 ieee80211_handle_roc_started(roc);
 382                 list_for_each_entry(dep, &roc->dependents, list)
 383                         ieee80211_handle_roc_started(dep);
 384
 385                 /* if it was pure TX, just finish right away */
 386                 if (!roc->duration)
 387                         goto finish;
 388
 389                 roc->started = true;
 390                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 391                                              msecs_to_jiffies(roc->duration));
 392         } else {
 393                 /* finish this ROC */
 394  finish:
 395                 list_del(&roc->list);
 396                 started = roc->started;
 397                 on_channel = roc->on_channel;
 398                 ieee80211_roc_notify_destroy(roc, !roc->abort);
 399
 400                 if (started && !on_channel) {
 401                         ieee80211_flush_queues(local, NULL);
 402
 403                         local->tmp_channel = NULL;
 404                         ieee80211_hw_config(local, 0);
 405
 406                         ieee80211_offchannel_return(local);
 407                 }
 408
 409                 ieee80211_recalc_idle(local);
 410
 411                 if (started)
 412                         ieee80211_start_next_roc(local);
 413                 else if (list_empty(&local->roc_list))
 414                         ieee80211_run_deferred_scan(local);
 415         }
 416
 417  out_unlock:
 418         mutex_unlock(&local->mtx);
 419 }
 420
 421 static void ieee80211_hw_roc_done(struct work_struct *work)
 422 {
 423         struct ieee80211_local *local =
 424                 container_of(work, struct ieee80211_local, hw_roc_done);
 425         struct ieee80211_roc_work *roc;
 426
 427         mutex_lock(&local->mtx);
 428
 429         if (list_empty(&local->roc_list))
 430                 goto out_unlock;
 431
 432         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 433                                list);
 434
 435         if (!roc->started)
 436                 goto out_unlock;
 437
 438         list_del(&roc->list);
 439
 440         ieee80211_roc_notify_destroy(roc, true);
 441
 442         /* if there's another roc, start it now */
 443         ieee80211_start_next_roc(local);
 444
 445  out_unlock:
 446         mutex_unlock(&local->mtx);
 447 }
 448
 449 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 450 {
 451         struct ieee80211_local *local = hw_to_local(hw);
 452
 453         trace_api_remain_on_channel_expired(local);
 454
 455         ieee80211_queue_work(hw, &local->hw_roc_done);
 456 }
 457 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 458
 459 void ieee80211_roc_setup(struct ieee80211_local *local)
 460 {
 461         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 462         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 463         INIT_LIST_HEAD(&local->roc_list);
 464 }
 465
 466 void ieee80211_roc_purge(struct ieee80211_local *local,
 467                          struct ieee80211_sub_if_data *sdata)
 468 {
 469         struct ieee80211_roc_work *roc, *tmp;
 470         LIST_HEAD(tmp_list);
 471
 472         mutex_lock(&local->mtx);
 473         list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
 474                 if (sdata && roc->sdata != sdata)
 475                         continue;
 476
 477                 if (roc->started && local->ops->remain_on_channel) {
 478                         /* can race, so ignore return value */
 479                         drv_cancel_remain_on_channel(local);
 480                 }
 481
 482                 list_move_tail(&roc->list, &tmp_list);
 483                 roc->abort = true;
 484         }
 485         mutex_unlock(&local->mtx);
 486
 487         list_for_each_entry_safe(roc, tmp, &tmp_list, list) {
 488                 if (local->ops->remain_on_channel) {
 489                         list_del(&roc->list);
 490                         ieee80211_roc_notify_destroy(roc, true);
 491                 } else {
 492                         ieee80211_queue_delayed_work(&local->hw, &roc->work, 0);
 493
 494                         /* work will clean up etc */
 495                         flush_delayed_work(&roc->work);
 496                         WARN_ON(!roc->to_be_freed);
 497                         kfree(roc);
 498                 }
 499         }
 500
 501         WARN_ON_ONCE(!list_empty(&tmp_list));
 502 }