linux/net/mac80211/offchannel.c
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   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 */
  27static 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 */
  64static 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
 105void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local)
 106{
 107        struct ieee80211_sub_if_data *sdata;
 108
 109        /*
 110         * notify the AP about us leaving the channel and stop all
 111         * STA interfaces.
 112         */
 113        mutex_lock(&local->iflist_mtx);
 114        list_for_each_entry(sdata, &local->interfaces, list) {
 115                if (!ieee80211_sdata_running(sdata))
 116                        continue;
 117
 118                if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
 119                        continue;
 120
 121                if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 122                        set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 123
 124                /* Check to see if we should disable beaconing. */
 125                if (sdata->vif.type == NL80211_IFTYPE_AP ||
 126                    sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 127                    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 128                        ieee80211_bss_info_change_notify(
 129                                sdata, BSS_CHANGED_BEACON_ENABLED);
 130
 131                if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 132                        netif_tx_stop_all_queues(sdata->dev);
 133                        if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 134                            sdata->u.mgd.associated)
 135                                ieee80211_offchannel_ps_enable(sdata);
 136                }
 137        }
 138        mutex_unlock(&local->iflist_mtx);
 139}
 140
 141void ieee80211_offchannel_return(struct ieee80211_local *local)
 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_P2P_DEVICE)
 148                        continue;
 149
 150                if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
 151                        clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
 152
 153                if (!ieee80211_sdata_running(sdata))
 154                        continue;
 155
 156                /* Tell AP we're back */
 157                if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 158                    sdata->u.mgd.associated)
 159                        ieee80211_offchannel_ps_disable(sdata);
 160
 161                if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
 162                        /*
 163                         * This may wake up queues even though the driver
 164                         * currently has them stopped. This is not very
 165                         * likely, since the driver won't have gotten any
 166                         * (or hardly any) new packets while we weren't
 167                         * on the right channel, and even if it happens
 168                         * it will at most lead to queueing up one more
 169                         * packet per queue in mac80211 rather than on
 170                         * the interface qdisc.
 171                         */
 172                        netif_tx_wake_all_queues(sdata->dev);
 173                }
 174
 175                if (sdata->vif.type == NL80211_IFTYPE_AP ||
 176                    sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 177                    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 178                        ieee80211_bss_info_change_notify(
 179                                sdata, BSS_CHANGED_BEACON_ENABLED);
 180        }
 181        mutex_unlock(&local->iflist_mtx);
 182}
 183
 184void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc)
 185{
 186        if (roc->notified)
 187                return;
 188
 189        if (roc->mgmt_tx_cookie) {
 190                if (!WARN_ON(!roc->frame)) {
 191                        ieee80211_tx_skb(roc->sdata, roc->frame);
 192                        roc->frame = NULL;
 193                }
 194        } else {
 195                cfg80211_ready_on_channel(&roc->sdata->wdev, (unsigned long)roc,
 196                                          roc->chan, roc->chan_type,
 197                                          roc->req_duration, GFP_KERNEL);
 198        }
 199
 200        roc->notified = true;
 201}
 202
 203static void ieee80211_hw_roc_start(struct work_struct *work)
 204{
 205        struct ieee80211_local *local =
 206                container_of(work, struct ieee80211_local, hw_roc_start);
 207        struct ieee80211_roc_work *roc, *dep, *tmp;
 208
 209        mutex_lock(&local->mtx);
 210
 211        if (list_empty(&local->roc_list))
 212                goto out_unlock;
 213
 214        roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
 215                               list);
 216
 217        if (!roc->started)
 218                goto out_unlock;
 219
 220        roc->hw_begun = true;
 221        roc->hw_start_time = local->hw_roc_start_time;
 222
 223        ieee80211_handle_roc_started(roc);
 224        list_for_each_entry_safe(dep, tmp, &roc->dependents, list) {
 225                ieee80211_handle_roc_started(dep);
 226
 227                if (dep->duration > roc->duration) {
 228                        u32 dur = dep->duration;
 229                        dep->duration = dur - roc->duration;
 230                        roc->duration = dur;
 231                        list_move(&dep->list, &roc->list);
 232                }
 233        }
 234 out_unlock:
 235        mutex_unlock(&local->mtx);
 236}
 237
 238void 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}
 248EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
 249
 250void 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
 296void 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
 321void 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);
 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
 392static 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
 420void 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}
 428EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
 429
 430void 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
 437void 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        mutex_unlock(&local->mtx);
 457
 458        list_for_each_entry_safe(roc, tmp, &tmp_list, list) {
 459                if (local->ops->remain_on_channel) {
 460                        list_del(&roc->list);
 461                        ieee80211_roc_notify_destroy(roc);
 462                } else {
 463                        ieee80211_queue_delayed_work(&local->hw, &roc->work, 0);
 464
 465                        /* work will clean up etc */
 466                        flush_delayed_work(&roc->work);
 467                }
 468        }
 469
 470        WARN_ON_ONCE(!list_empty(&tmp_list));
 471}
 472
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