/*
 * Off-channel operation helpers
 *
 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
 * Copyright 2004, Instant802 Networks, Inc.
 * Copyright 2005, Devicescape Software, Inc.
 * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
 * Copyright 2009       Johannes Berg <johannes@sipsolutions.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/export.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"

/*
 * Tell our hardware to disable PS.
 * Optionally inform AP that we will go to sleep so that it will buffer
 * the frames while we are doing off-channel work.  This is optional
 * because we *may* be doing work on-operating channel, and want our
 * hardware unconditionally awake, but still let the AP send us normal frames.
 */
static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata)
{
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;

        local->offchannel_ps_enabled = false;

        /* FIXME: what to do when local->pspolling is true? */

        del_timer_sync(&local->dynamic_ps_timer);
        del_timer_sync(&ifmgd->bcn_mon_timer);
        del_timer_sync(&ifmgd->conn_mon_timer);

        cancel_work_sync(&local->dynamic_ps_enable_work);

        if (local->hw.conf.flags & IEEE80211_CONF_PS) {
                local->offchannel_ps_enabled = true;
                local->hw.conf.flags &= ~IEEE80211_CONF_PS;
                ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
        }

        if (!local->offchannel_ps_enabled ||
            !ieee80211_hw_check(&local->hw, PS_NULLFUNC_STACK))
                /*
                 * If power save was enabled, no need to send a nullfunc
                 * frame because AP knows that we are sleeping. But if the
                 * hardware is creating the nullfunc frame for power save
                 * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
                 * enabled) and power save was enabled, the firmware just
                 * sent a null frame with power save disabled. So we need
                 * to send a new nullfunc frame to inform the AP that we
                 * are again sleeping.
                 */
                ieee80211_send_nullfunc(local, sdata, true);
}

/* inform AP that we are awake again, unless power save is enabled */
static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
{
        struct ieee80211_local *local = sdata->local;

        if (!local->ps_sdata)
                ieee80211_send_nullfunc(local, sdata, false);
        else if (local->offchannel_ps_enabled) {
                /*
                 * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
                 * will send a nullfunc frame with the powersave bit set
                 * even though the AP already knows that we are sleeping.
                 * This could be avoided by sending a null frame with power
                 * save bit disabled before enabling the power save, but
                 * this doesn't gain anything.
                 *
                 * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
                 * to send a nullfunc frame because AP already knows that
                 * we are sleeping, let's just enable power save mode in
                 * hardware.
                 */
                /* TODO:  Only set hardware if CONF_PS changed?
                 * TODO:  Should we set offchannel_ps_enabled to false?
                 */
                local->hw.conf.flags |= IEEE80211_CONF_PS;
                ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
        } else if (local->hw.conf.dynamic_ps_timeout > 0) {
                /*
                 * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
                 * had been running before leaving the operating channel,
                 * restart the timer now and send a nullfunc frame to inform
                 * the AP that we are awake.
                 */
                ieee80211_send_nullfunc(local, sdata, false);
                mod_timer(&local->dynamic_ps_timer, jiffies +
                          msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
        }

        ieee80211_sta_reset_beacon_monitor(sdata);
        ieee80211_sta_reset_conn_monitor(sdata);
}

void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local)
{
        struct ieee80211_sub_if_data *sdata;

        if (WARN_ON(local->use_chanctx))
                return;

        /*
         * notify the AP about us leaving the channel and stop all
         * STA interfaces.
         */

        /*
         * Stop queues and transmit all frames queued by the driver
         * before sending nullfunc to enable powersave at the AP.
         */
        ieee80211_stop_queues_by_reason(&local->hw, IEEE80211_MAX_QUEUE_MAP,
                                        IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL,
                                        false);
        ieee80211_flush_queues(local, NULL, false);

        mutex_lock(&local->iflist_mtx);
        list_for_each_entry(sdata, &local->interfaces, list) {
                if (!ieee80211_sdata_running(sdata))
                        continue;

                if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE ||
                    sdata->vif.type == NL80211_IFTYPE_NAN)
                        continue;

                if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
                        set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);

                /* Check to see if we should disable beaconing. */
                if (sdata->vif.bss_conf.enable_beacon) {
                        set_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
                                &sdata->state);
                        sdata->vif.bss_conf.enable_beacon = false;
                        ieee80211_bss_info_change_notify(
                                sdata, BSS_CHANGED_BEACON_ENABLED);
                }

                if (sdata->vif.type == NL80211_IFTYPE_STATION &&
                    sdata->u.mgd.associated)
                        ieee80211_offchannel_ps_enable(sdata);
        }
        mutex_unlock(&local->iflist_mtx);
}

void ieee80211_offchannel_return(struct ieee80211_local *local)
{
        struct ieee80211_sub_if_data *sdata;

        if (WARN_ON(local->use_chanctx))
                return;

        mutex_lock(&local->iflist_mtx);
        list_for_each_entry(sdata, &local->interfaces, list) {
                if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
                        continue;

                if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
                        clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);

                if (!ieee80211_sdata_running(sdata))
                        continue;

                /* Tell AP we're back */
                if (sdata->vif.type == NL80211_IFTYPE_STATION &&
                    sdata->u.mgd.associated)
                        ieee80211_offchannel_ps_disable(sdata);

                if (test_and_clear_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
                                       &sdata->state)) {
                        sdata->vif.bss_conf.enable_beacon = true;
                        ieee80211_bss_info_change_notify(
                                sdata, BSS_CHANGED_BEACON_ENABLED);
                }
        }
        mutex_unlock(&local->iflist_mtx);

        ieee80211_wake_queues_by_reason(&local->hw, IEEE80211_MAX_QUEUE_MAP,
                                        IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL,
                                        false);
}

static void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc)
{
        /* was never transmitted */
        if (roc->frame) {
                cfg80211_mgmt_tx_status(&roc->sdata->wdev, roc->mgmt_tx_cookie,
                                        roc->frame->data, roc->frame->len,
                                        false, GFP_KERNEL);
                ieee80211_free_txskb(&roc->sdata->local->hw, roc->frame);
        }

        if (!roc->mgmt_tx_cookie)
                cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
                                                   roc->cookie, roc->chan,
                                                   GFP_KERNEL);

        list_del(&roc->list);
        kfree(roc);
}

static unsigned long ieee80211_end_finished_rocs(struct ieee80211_local *local,
                                                 unsigned long now)
{
        struct ieee80211_roc_work *roc, *tmp;
        long remaining_dur_min = LONG_MAX;

        lockdep_assert_held(&local->mtx);

        list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
                long remaining;

                if (!roc->started)
                        break;

                remaining = roc->start_time +
                            msecs_to_jiffies(roc->duration) -
                            now;

                /* In case of HW ROC, it is possible that the HW finished the
                 * ROC session before the actual requested time. In such a case
                 * end the ROC session (disregarding the remaining time).
                 */
                if (roc->abort || roc->hw_begun || remaining <= 0)
                        ieee80211_roc_notify_destroy(roc);
                else
                        remaining_dur_min = min(remaining_dur_min, remaining);
        }

        return remaining_dur_min;
}

static bool ieee80211_recalc_sw_work(struct ieee80211_local *local,
                                     unsigned long now)
{
        long dur = ieee80211_end_finished_rocs(local, now);

        if (dur == LONG_MAX)
                return false;

        mod_delayed_work(local->workqueue, &local->roc_work, dur);
        return true;
}

static void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc,
                                         unsigned long start_time)
{
        if (WARN_ON(roc->notified))
                return;

        roc->start_time = start_time;
        roc->started = true;

        if (roc->mgmt_tx_cookie) {
                if (!WARN_ON(!roc->frame)) {
                        ieee80211_tx_skb_tid_band(roc->sdata, roc->frame, 7,
                                                  roc->chan->band);
                        roc->frame = NULL;
                }
        } else {
                cfg80211_ready_on_channel(&roc->sdata->wdev, roc->cookie,
                                          roc->chan, roc->req_duration,
                                          GFP_KERNEL);
        }

        roc->notified = true;
}

static void ieee80211_hw_roc_start(struct work_struct *work)
{
        struct ieee80211_local *local =
                container_of(work, struct ieee80211_local, hw_roc_start);
        struct ieee80211_roc_work *roc;

        mutex_lock(&local->mtx);

        list_for_each_entry(roc, &local->roc_list, list) {
                if (!roc->started)
                        break;

                roc->hw_begun = true;
                ieee80211_handle_roc_started(roc, local->hw_roc_start_time);
        }

        mutex_unlock(&local->mtx);
}

void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
{
        struct ieee80211_local *local = hw_to_local(hw);

        local->hw_roc_start_time = jiffies;

        trace_api_ready_on_channel(local);

        ieee80211_queue_work(hw, &local->hw_roc_start);
}
EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);

static void _ieee80211_start_next_roc(struct ieee80211_local *local)
{
        struct ieee80211_roc_work *roc, *tmp;
        enum ieee80211_roc_type type;
        u32 min_dur, max_dur;

        lockdep_assert_held(&local->mtx);

        if (WARN_ON(list_empty(&local->roc_list)))
                return;

        roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
                               list);

        if (WARN_ON(roc->started))
                return;

        min_dur = roc->duration;
        max_dur = roc->duration;
        type = roc->type;

        list_for_each_entry(tmp, &local->roc_list, list) {
                if (tmp == roc)
                        continue;
                if (tmp->sdata != roc->sdata || tmp->chan != roc->chan)
                        break;
                max_dur = max(tmp->duration, max_dur);
                min_dur = min(tmp->duration, min_dur);
                type = max(tmp->type, type);
        }

        if (local->ops->remain_on_channel) {
                int ret = drv_remain_on_channel(local, roc->sdata, roc->chan,
                                                max_dur, type);

                if (ret) {
                        wiphy_warn(local->hw.wiphy,
                                   "failed to start next HW ROC (%d)\n", ret);
                        /*
                         * queue the work struct again to avoid recursion
                         * when multiple failures occur
                         */
                        list_for_each_entry(tmp, &local->roc_list, list) {
                                if (tmp->sdata != roc->sdata ||
                                    tmp->chan != roc->chan)
                                        break;
                                tmp->started = true;
                                tmp->abort = true;
                        }
                        ieee80211_queue_work(&local->hw, &local->hw_roc_done);
                        return;
                }

                /* we'll notify about the start once the HW calls back */
                list_for_each_entry(tmp, &local->roc_list, list) {
                        if (tmp->sdata != roc->sdata || tmp->chan != roc->chan)
                                break;
                        tmp->started = true;
                }
        } else {
                /* If actually operating on the desired channel (with at least
                 * 20 MHz channel width) don't stop all the operations but still
                 * treat it as though the ROC operation started properly, so
                 * other ROC operations won't interfere with this one.
                 */
                roc->on_channel = roc->chan == local->_oper_chandef.chan &&
                                  local->_oper_chandef.width != NL80211_CHAN_WIDTH_5 &&
                                  local->_oper_chandef.width != NL80211_CHAN_WIDTH_10;

                /* start this ROC */
                ieee80211_recalc_idle(local);

                if (!roc->on_channel) {
                        ieee80211_offchannel_stop_vifs(local);

                        local->tmp_channel = roc->chan;
                        ieee80211_hw_config(local, 0);
                }

                ieee80211_queue_delayed_work(&local->hw, &local->roc_work,
                                             msecs_to_jiffies(min_dur));

                /* tell userspace or send frame(s) */
                list_for_each_entry(tmp, &local->roc_list, list) {
                        if (tmp->sdata != roc->sdata || tmp->chan != roc->chan)
                                break;

                        tmp->on_channel = roc->on_channel;
                        ieee80211_handle_roc_started(tmp, jiffies);
                }
        }
}

void ieee80211_start_next_roc(struct ieee80211_local *local)
{
        struct ieee80211_roc_work *roc;

        lockdep_assert_held(&local->mtx);

        if (list_empty(&local->roc_list)) {
                ieee80211_run_deferred_scan(local);
                return;
        }

        /* defer roc if driver is not started (i.e. during reconfig) */
        if (local->in_reconfig)
                return;

        roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
                               list);

        if (WARN_ON_ONCE(roc->started))
                return;

        if (local->ops->remain_on_channel) {
                _ieee80211_start_next_roc(local);
        } else {
                /* delay it a bit */
                ieee80211_queue_delayed_work(&local->hw, &local->roc_work,
                                             round_jiffies_relative(HZ/2));
        }
}

static void __ieee80211_roc_work(struct ieee80211_local *local)
{
        struct ieee80211_roc_work *roc;
        bool on_channel;

        lockdep_assert_held(&local->mtx);

        if (WARN_ON(local->ops->remain_on_channel))
                return;

        roc = list_first_entry_or_null(&local->roc_list,
                                       struct ieee80211_roc_work, list);
        if (!roc)
                return;

        if (!roc->started) {
                WARN_ON(local->use_chanctx);
                _ieee80211_start_next_roc(local);
        } else {
                on_channel = roc->on_channel;
                if (ieee80211_recalc_sw_work(local, jiffies))
                        return;

                /* careful - roc pointer became invalid during recalc */

                if (!on_channel) {
                        ieee80211_flush_queues(local, NULL, false);

                        local->tmp_channel = NULL;
                        ieee80211_hw_config(local, 0);

                        ieee80211_offchannel_return(local);
                }

                ieee80211_recalc_idle(local);
                ieee80211_start_next_roc(local);
        }
}

static void ieee80211_roc_work(struct work_struct *work)
{
        struct ieee80211_local *local =
                container_of(work, struct ieee80211_local, roc_work.work);

        mutex_lock(&local->mtx);
        __ieee80211_roc_work(local);
        mutex_unlock(&local->mtx);
}

static void ieee80211_hw_roc_done(struct work_struct *work)
{
        struct ieee80211_local *local =
                container_of(work, struct ieee80211_local, hw_roc_done);

        mutex_lock(&local->mtx);

        ieee80211_end_finished_rocs(local, jiffies);

        /* if there's another roc, start it now */
        ieee80211_start_next_roc(local);

        mutex_unlock(&local->mtx);
}

void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
{
        struct ieee80211_local *local = hw_to_local(hw);

        trace_api_remain_on_channel_expired(local);

        ieee80211_queue_work(hw, &local->hw_roc_done);
}
EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);

static bool
ieee80211_coalesce_hw_started_roc(struct ieee80211_local *local,
                                  struct ieee80211_roc_work *new_roc,
                                  struct ieee80211_roc_work *cur_roc)
{
        unsigned long now = jiffies;
        unsigned long remaining;

        if (WARN_ON(!cur_roc->started))
                return false;

        /* if it was scheduled in the hardware, but not started yet,
         * we can only combine if the older one had a longer duration
         */
        if (!cur_roc->hw_begun && new_roc->duration > cur_roc->duration)
                return false;

        remaining = cur_roc->start_time +
                    msecs_to_jiffies(cur_roc->duration) -
                    now;

        /* if it doesn't fit entirely, schedule a new one */
        if (new_roc->duration > jiffies_to_msecs(remaining))
                return false;

        /* add just after the current one so we combine their finish later */
        list_add(&new_roc->list, &cur_roc->list);

        /* if the existing one has already begun then let this one also
         * begin, otherwise they'll both be marked properly by the work
         * struct that runs once the driver notifies us of the beginning
         */
        if (cur_roc->hw_begun) {
                new_roc->hw_begun = true;
                ieee80211_handle_roc_started(new_roc, now);
        }

        return true;
}

static int ieee80211_start_roc_work(struct ieee80211_local *local,
                                    struct ieee80211_sub_if_data *sdata,
                                    struct ieee80211_channel *channel,
                                    unsigned int duration, u64 *cookie,
                                    struct sk_buff *txskb,
                                    enum ieee80211_roc_type type)
{
        struct ieee80211_roc_work *roc, *tmp;
        bool queued = false, combine_started = true;
        int ret;

        lockdep_assert_held(&local->mtx);

        if (local->use_chanctx && !local->ops->remain_on_channel)
                return -EOPNOTSUPP;

        roc = kzalloc(sizeof(*roc), GFP_KERNEL);
        if (!roc)
                return -ENOMEM;

        /*
         * If the duration is zero, then the driver
         * wouldn't actually do anything. Set it to
         * 10 for now.
         *
         * TODO: cancel the off-channel operation
         *       when we get the SKB's TX status and
         *       the wait time was zero before.
         */
        if (!duration)
                duration = 10;

        roc->chan = channel;
        roc->duration = duration;
        roc->req_duration = duration;
        roc->frame = txskb;
        roc->type = type;
        roc->sdata = sdata;

        /*
         * cookie is either the roc cookie (for normal roc)
         * or the SKB (for mgmt TX)
         */
        if (!txskb) {
                roc->cookie = ieee80211_mgmt_tx_cookie(local);
                *cookie = roc->cookie;
        } else {
                roc->mgmt_tx_cookie = *cookie;
        }

        /* if there's no need to queue, handle it immediately */
        if (list_empty(&local->roc_list) &&
            !local->scanning && !ieee80211_is_radar_required(local)) {
                /* if not HW assist, just queue & schedule work */
                if (!local->ops->remain_on_channel) {
                        list_add_tail(&roc->list, &local->roc_list);
                        ieee80211_queue_delayed_work(&local->hw,
                                                     &local->roc_work, 0);
                } else {
                        /* otherwise actually kick it off here
                         * (for error handling)
                         */
                        ret = drv_remain_on_channel(local, sdata, channel,
                                                    duration, type);
                        if (ret) {
                                kfree(roc);
                                return ret;
                        }
                        roc->started = true;
                        list_add_tail(&roc->list, &local->roc_list);
                }

                return 0;
        }

        /* otherwise handle queueing */

        list_for_each_entry(tmp, &local->roc_list, list) {
                if (tmp->chan != channel || tmp->sdata != sdata)
                        continue;

                /*
                 * Extend this ROC if possible: If it hasn't started, add
                 * just after the new one to combine.
                 */
                if (!tmp->started) {
                        list_add(&roc->list, &tmp->list);
                        queued = true;
                        break;
                }

                if (!combine_started)
                        continue;

                if (!local->ops->remain_on_channel) {
                        /* If there's no hardware remain-on-channel, and
                         * doing so won't push us over the maximum r-o-c
                         * we allow, then we can just add the new one to
                         * the list and mark it as having started now.
                         * If it would push over the limit, don't try to
                         * combine with other started ones (that haven't
                         * been running as long) but potentially sort it
                         * with others that had the same fate.
                         */
                        unsigned long now = jiffies;
                        u32 elapsed = jiffies_to_msecs(now - tmp->start_time);
                        struct wiphy *wiphy = local->hw.wiphy;
                        u32 max_roc = wiphy->max_remain_on_channel_duration;

                        if (elapsed + roc->duration > max_roc) {
                                combine_started = false;
                                continue;
                        }

                        list_add(&roc->list, &tmp->list);
                        queued = true;
                        roc->on_channel = tmp->on_channel;
                        ieee80211_handle_roc_started(roc, now);
                        ieee80211_recalc_sw_work(local, now);
                        break;
                }

                queued = ieee80211_coalesce_hw_started_roc(local, roc, tmp);
                if (queued)
                        break;
                /* if it wasn't queued, perhaps it can be combined with
                 * another that also couldn't get combined previously,
                 * but no need to check for already started ones, since
                 * that can't work.
                 */
                combine_started = false;
        }

        if (!queued)
                list_add_tail(&roc->list, &local->roc_list);

        return 0;
}

int ieee80211_remain_on_channel(struct wiphy *wiphy, struct wireless_dev *wdev,
                                struct ieee80211_channel *chan,
                                unsigned int duration, u64 *cookie)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
        struct ieee80211_local *local = sdata->local;
        int ret;

        mutex_lock(&local->mtx);
        ret = ieee80211_start_roc_work(local, sdata, chan,
                                       duration, cookie, NULL,
                                       IEEE80211_ROC_TYPE_NORMAL);
        mutex_unlock(&local->mtx);

        return ret;
}

static int ieee80211_cancel_roc(struct ieee80211_local *local,
                                u64 cookie, bool mgmt_tx)
{
        struct ieee80211_roc_work *roc, *tmp, *found = NULL;
        int ret;

        if (!cookie)
                return -ENOENT;

        mutex_lock(&local->mtx);
        list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
                if (!mgmt_tx && roc->cookie != cookie)
                        continue;
                else if (mgmt_tx && roc->mgmt_tx_cookie != cookie)
                        continue;

                found = roc;
                break;
        }

        if (!found) {
                mutex_unlock(&local->mtx);
                return -ENOENT;
        }

        if (!found->started) {
                ieee80211_roc_notify_destroy(found);
                goto out_unlock;
        }

        if (local->ops->remain_on_channel) {
                ret = drv_cancel_remain_on_channel(local);
                if (WARN_ON_ONCE(ret)) {
                        mutex_unlock(&local->mtx);
                        return ret;
                }

                /* TODO:
                 * if multiple items were combined here then we really shouldn't
                 * cancel them all - we should wait for as much time as needed
                 * for the longest remaining one, and only then cancel ...
                 */
                list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
                        if (!roc->started)
                                break;
                        if (roc == found)
                                found = NULL;
                        ieee80211_roc_notify_destroy(roc);
                }

                /* that really must not happen - it was started */
                WARN_ON(found);

                ieee80211_start_next_roc(local);
        } else {
                /* go through work struct to return to the operating channel */
                found->abort = true;
                mod_delayed_work(local->workqueue, &local->roc_work, 0);
        }

 out_unlock:
        mutex_unlock(&local->mtx);

        return 0;
}

int ieee80211_cancel_remain_on_channel(struct wiphy *wiphy,
                                       struct wireless_dev *wdev, u64 cookie)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
        struct ieee80211_local *local = sdata->local;

        return ieee80211_cancel_roc(local, cookie, false);
}

int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
                      struct cfg80211_mgmt_tx_params *params, u64 *cookie)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
        struct ieee80211_local *local = sdata->local;
        struct sk_buff *skb;
        struct sta_info *sta;
        const struct ieee80211_mgmt *mgmt = (void *)params->buf;
        bool need_offchan = false;
        u32 flags;
        int ret;
        u8 *data;

        if (params->dont_wait_for_ack)
                flags = IEEE80211_TX_CTL_NO_ACK;
        else
                flags = IEEE80211_TX_INTFL_NL80211_FRAME_TX |
                        IEEE80211_TX_CTL_REQ_TX_STATUS;

        if (params->no_cck)
                flags |= IEEE80211_TX_CTL_NO_CCK_RATE;

        switch (sdata->vif.type) {
        case NL80211_IFTYPE_ADHOC:
                if (!sdata->vif.bss_conf.ibss_joined)
                        need_offchan = true;
                /* fall through */
#ifdef CONFIG_MAC80211_MESH
        case NL80211_IFTYPE_MESH_POINT:
                if (ieee80211_vif_is_mesh(&sdata->vif) &&
                    !sdata->u.mesh.mesh_id_len)
                        need_offchan = true;
                /* fall through */
#endif
        case NL80211_IFTYPE_AP:
        case NL80211_IFTYPE_AP_VLAN:
        case NL80211_IFTYPE_P2P_GO:
                if (sdata->vif.type != NL80211_IFTYPE_ADHOC &&
                    !ieee80211_vif_is_mesh(&sdata->vif) &&
                    !rcu_access_pointer(sdata->bss->beacon))
                        need_offchan = true;
                if (!ieee80211_is_action(mgmt->frame_control) ||
                    mgmt->u.action.category == WLAN_CATEGORY_PUBLIC ||
                    mgmt->u.action.category == WLAN_CATEGORY_SELF_PROTECTED ||
                    mgmt->u.action.category == WLAN_CATEGORY_SPECTRUM_MGMT)
                        break;
                rcu_read_lock();
                sta = sta_info_get_bss(sdata, mgmt->da);
                rcu_read_unlock();
                if (!sta)
                        return -ENOLINK;
                break;
        case NL80211_IFTYPE_STATION:
        case NL80211_IFTYPE_P2P_CLIENT:
                sdata_lock(sdata);
                if (!sdata->u.mgd.associated ||
                    (params->offchan && params->wait &&
                     local->ops->remain_on_channel &&
                     memcmp(sdata->u.mgd.associated->bssid,
                            mgmt->bssid, ETH_ALEN)))
                        need_offchan = true;
                sdata_unlock(sdata);
                break;
        case NL80211_IFTYPE_P2P_DEVICE:
                need_offchan = true;
                break;
        case NL80211_IFTYPE_NAN:
        default:
                return -EOPNOTSUPP;
        }

        /* configurations requiring offchan cannot work if no channel has been
         * specified
         */
        if (need_offchan && !params->chan)
                return -EINVAL;

        mutex_lock(&local->mtx);

        /* Check if the operating channel is the requested channel */
        if (!need_offchan) {
                struct ieee80211_chanctx_conf *chanctx_conf;

                rcu_read_lock();
                chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);

                if (chanctx_conf) {
                        need_offchan = params->chan &&
                                       (params->chan !=
                                        chanctx_conf->def.chan);
                } else if (!params->chan) {
                        ret = -EINVAL;
                        rcu_read_unlock();
                        goto out_unlock;
                } else {
                        need_offchan = true;
                }
                rcu_read_unlock();
        }

        if (need_offchan && !params->offchan) {
                ret = -EBUSY;
                goto out_unlock;
        }

        skb = dev_alloc_skb(local->hw.extra_tx_headroom + params->len);
        if (!skb) {
                ret = -ENOMEM;
                goto out_unlock;
        }
        skb_reserve(skb, local->hw.extra_tx_headroom);

        data = skb_put(skb, params->len);
        memcpy(data, params->buf, params->len);

        /* Update CSA counters */
        if (sdata->vif.csa_active &&
            (sdata->vif.type == NL80211_IFTYPE_AP ||
             sdata->vif.type == NL80211_IFTYPE_MESH_POINT ||
             sdata->vif.type == NL80211_IFTYPE_ADHOC) &&
            params->n_csa_offsets) {
                int i;
                struct beacon_data *beacon = NULL;

                rcu_read_lock();

                if (sdata->vif.type == NL80211_IFTYPE_AP)
                        beacon = rcu_dereference(sdata->u.ap.beacon);
                else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
                        beacon = rcu_dereference(sdata->u.ibss.presp);
                else if (ieee80211_vif_is_mesh(&sdata->vif))
                        beacon = rcu_dereference(sdata->u.mesh.beacon);

                if (beacon)
                        for (i = 0; i < params->n_csa_offsets; i++)
                                data[params->csa_offsets[i]] =
                                        beacon->csa_current_counter;

                rcu_read_unlock();
        }

        IEEE80211_SKB_CB(skb)->flags = flags;

        skb->dev = sdata->dev;

        if (!params->dont_wait_for_ack) {
                /* make a copy to preserve the frame contents
                 * in case of encryption.
                 */
                ret = ieee80211_attach_ack_skb(local, skb, cookie, GFP_KERNEL);
                if (ret) {
                        kfree_skb(skb);
                        goto out_unlock;
                }
        } else {
                /* Assign a dummy non-zero cookie, it's not sent to
                 * userspace in this case but we rely on its value
                 * internally in the need_offchan case to distinguish
                 * mgmt-tx from remain-on-channel.
                 */
                *cookie = 0xffffffff;
        }

        if (!need_offchan) {
                ieee80211_tx_skb(sdata, skb);
                ret = 0;
                goto out_unlock;
        }

        IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_TX_OFFCHAN |
                                        IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
        if (ieee80211_hw_check(&local->hw, QUEUE_CONTROL))
                IEEE80211_SKB_CB(skb)->hw_queue =
                        local->hw.offchannel_tx_hw_queue;

        /* This will handle all kinds of coalescing and immediate TX */
        ret = ieee80211_start_roc_work(local, sdata, params->chan,
                                       params->wait, cookie, skb,
                                       IEEE80211_ROC_TYPE_MGMT_TX);
        if (ret)
                ieee80211_free_txskb(&local->hw, skb);
 out_unlock:
        mutex_unlock(&local->mtx);
        return ret;
}

int ieee80211_mgmt_tx_cancel_wait(struct wiphy *wiphy,
                                  struct wireless_dev *wdev, u64 cookie)
{
        struct ieee80211_local *local = wiphy_priv(wiphy);

        return ieee80211_cancel_roc(local, cookie, true);
}

void ieee80211_roc_setup(struct ieee80211_local *local)
{
        INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
        INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
        INIT_DELAYED_WORK(&local->roc_work, ieee80211_roc_work);
        INIT_LIST_HEAD(&local->roc_list);
}

void ieee80211_roc_purge(struct ieee80211_local *local,
                         struct ieee80211_sub_if_data *sdata)
{
        struct ieee80211_roc_work *roc, *tmp;
        bool work_to_do = false;

        mutex_lock(&local->mtx);
        list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
                if (sdata && roc->sdata != sdata)
                        continue;

                if (roc->started) {
                        if (local->ops->remain_on_channel) {
                                /* can race, so ignore return value */
                                drv_cancel_remain_on_channel(local);
                                ieee80211_roc_notify_destroy(roc);
                        } else {
                                roc->abort = true;
                                work_to_do = true;
                        }
                } else {
                        ieee80211_roc_notify_destroy(roc);
                }

        }
        if (work_to_do)
                __ieee80211_roc_work(local);
        mutex_unlock(&local->mtx);
}