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         mutex_lock(&local->iflist_mtx);
 117         list_for_each_entry(sdata, &local->interfaces, list) {
 118                 if (!ieee80211_sdata_running(sdata))
 119                         continue;
 120
 121                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
 122                         continue;
 123
 124                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 125                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 126
 127                 /* Check to see if we should disable beaconing. */
 128                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 129                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 130                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 131                         ieee80211_bss_info_change_notify(
 132                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 133
 134                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 135                         netif_tx_stop_all_queues(sdata->dev);
 136                         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 137                             sdata->u.mgd.associated)
 138                                 ieee80211_offchannel_ps_enable(sdata);
 139                 }
 140         }
 141         mutex_unlock(&local->iflist_mtx);
 142 }
 143
 144 void ieee80211_offchannel_return(struct ieee80211_local *local)
 145 {
 146         struct ieee80211_sub_if_data *sdata;
 147
 148         if (WARN_ON(local->use_chanctx))
 149                 return;
 150
 151         mutex_lock(&local->iflist_mtx);
 152         list_for_each_entry(sdata, &local->interfaces, list) {
 153                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
 154                         continue;
 155
 156                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 157                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 158
 159                 if (!ieee80211_sdata_running(sdata))
 160                         continue;
 161
 162                 /* Tell AP we're back */
 163                 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 164                     sdata->u.mgd.associated)
 165                         ieee80211_offchannel_ps_disable(sdata);
 166
 167                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 168                         /*
 169                          * This may wake up queues even though the driver
 170                          * currently has them stopped. This is not very
 171                          * likely, since the driver won't have gotten any
 172                          * (or hardly any) new packets while we weren't
 173                          * on the right channel, and even if it happens
 174                          * it will at most lead to queueing up one more
 175                          * packet per queue in mac80211 rather than on
 176                          * the interface qdisc.
 177                          */
 178                         netif_tx_wake_all_queues(sdata->dev);
 179                 }
 180
 181                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 182                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 183                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 184                         ieee80211_bss_info_change_notify(
 185                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 186         }
 187         mutex_unlock(&local->iflist_mtx);
 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);
 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)
 303 {
 304         struct ieee80211_roc_work *dep, *tmp;
 305
 306         /* was never transmitted */
 307         if (roc->frame) {
 308                 cfg80211_mgmt_tx_status(&roc->sdata->wdev,
 309                                         (unsigned long)roc->frame,
 310                                         roc->frame->data, roc->frame->len,
 311                                         false, GFP_KERNEL);
 312                 kfree_skb(roc->frame);
 313         }
 314
 315         if (!roc->mgmt_tx_cookie)
 316                 cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
 317                                                    roc->cookie, roc->chan,
 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                 ieee80211_hw_config(local, 0);
 357
 358                 /* tell userspace or send frame */
 359                 ieee80211_handle_roc_started(roc);
 360                 list_for_each_entry(dep, &roc->dependents, list)
 361                         ieee80211_handle_roc_started(dep);
 362
 363                 /* if it was pure TX, just finish right away */
 364                 if (!roc->duration)
 365                         goto finish;
 366
 367                 roc->started = true;
 368                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
 369                                              msecs_to_jiffies(roc->duration));
 370         } else {
 371                 /* finish this ROC */
 372  finish:
 373                 list_del(&roc->list);
 374                 started = roc->started;
 375                 ieee80211_roc_notify_destroy(roc);
 376
 377                 if (started) {
 378                         drv_flush(local, false);
 379
 380                         local->tmp_channel = NULL;
 381                         ieee80211_hw_config(local, 0);
 382
 383                         ieee80211_offchannel_return(local);
 384                 }
 385
 386                 ieee80211_recalc_idle(local);
 387
 388                 if (started)
 389                         ieee80211_start_next_roc(local);
 390         }
 391
 392  out_unlock:
 393         mutex_unlock(&local->mtx);
 394 }
 395
 396 static void ieee80211_hw_roc_done(struct work_struct *work)
 397 {
 398         struct ieee80211_local *local =
 399                 container_of(work, struct ieee80211_local, hw_roc_done);
 400         struct ieee80211_roc_work *roc;
 401
 402         mutex_lock(&local->mtx);
 403
 404         if (list_empty(&local->roc_list))
 405                 goto out_unlock;
 406
 407         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 408                                list);
 409
 410         if (!roc->started)
 411                 goto out_unlock;
 412
 413         list_del(&roc->list);
 414
 415         ieee80211_roc_notify_destroy(roc);
 416
 417         /* if there's another roc, start it now */
 418         ieee80211_start_next_roc(local);
 419
 420  out_unlock:
 421         mutex_unlock(&local->mtx);
 422 }
 423
 424 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
 425 {
 426         struct ieee80211_local *local = hw_to_local(hw);
 427
 428         trace_api_remain_on_channel_expired(local);
 429
 430         ieee80211_queue_work(hw, &local->hw_roc_done);
 431 }
 432 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 433
 434 void ieee80211_roc_setup(struct ieee80211_local *local)
 435 {
 436         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
 437         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
 438         INIT_LIST_HEAD(&local->roc_list);
 439 }
 440
 441 void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata)
 442 {
 443         struct ieee80211_local *local = sdata->local;
 444         struct ieee80211_roc_work *roc, *tmp;
 445         LIST_HEAD(tmp_list);
 446
 447         mutex_lock(&local->mtx);
 448         list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
 449                 if (roc->sdata != sdata)
 450                         continue;
 451
 452                 if (roc->started && local->ops->remain_on_channel) {
 453                         /* can race, so ignore return value */
 454                         drv_cancel_remain_on_channel(local);
 455                 }
 456
 457                 list_move_tail(&roc->list, &tmp_list);
 458                 roc->abort = true;
 459         }
 460         mutex_unlock(&local->mtx);
 461
 462         list_for_each_entry_safe(roc, tmp, &tmp_list, list) {
 463                 if (local->ops->remain_on_channel) {
 464                         list_del(&roc->list);
 465                         ieee80211_roc_notify_destroy(roc);
 466                 } else {
 467                         ieee80211_queue_delayed_work(&local->hw, &roc->work, 0);
 468
 469                         /* work will clean up etc */
 470                         flush_delayed_work(&roc->work);
 471                 }
 472         }
 473
 474         WARN_ON_ONCE(!list_empty(&tmp_list));
 475 }