/*
 * Interface handling
 *
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
 * Copyright 2008, 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/slab.h>
#include <linux/kernel.h>
#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <net/mac80211.h>
#include <net/ieee80211_radiotap.h>
#include "ieee80211_i.h"
#include "sta_info.h"
#include "debugfs_netdev.h"
#include "mesh.h"
#include "led.h"
#include "driver-ops.h"
#include "wme.h"
#include "rate.h"

/**
 * DOC: Interface list locking
 *
 * The interface list in each struct ieee80211_local is protected
 * three-fold:
 *
 * (1) modifications may only be done under the RTNL
 * (2) modifications and readers are protected against each other by
 *     the iflist_mtx.
 * (3) modifications are done in an RCU manner so atomic readers
 *     can traverse the list in RCU-safe blocks.
 *
 * As a consequence, reads (traversals) of the list can be protected
 * by either the RTNL, the iflist_mtx or RCU.
 */

bool __ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata)
{
        struct ieee80211_chanctx_conf *chanctx_conf;
        int power;

        rcu_read_lock();
        chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
        if (!chanctx_conf) {
                rcu_read_unlock();
                return false;
        }

        power = chanctx_conf->def.chan->max_power;
        rcu_read_unlock();

        if (sdata->user_power_level != IEEE80211_UNSET_POWER_LEVEL)
                power = min(power, sdata->user_power_level);

        if (sdata->ap_power_level != IEEE80211_UNSET_POWER_LEVEL)
                power = min(power, sdata->ap_power_level);

        if (power != sdata->vif.bss_conf.txpower) {
                sdata->vif.bss_conf.txpower = power;
                ieee80211_hw_config(sdata->local, 0);
                return true;
        }

        return false;
}

void ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata)
{
        if (__ieee80211_recalc_txpower(sdata))
                ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_TXPOWER);
}

static u32 __ieee80211_idle_off(struct ieee80211_local *local)
{
        if (!(local->hw.conf.flags & IEEE80211_CONF_IDLE))
                return 0;

        local->hw.conf.flags &= ~IEEE80211_CONF_IDLE;
        return IEEE80211_CONF_CHANGE_IDLE;
}

static u32 __ieee80211_idle_on(struct ieee80211_local *local)
{
        if (local->hw.conf.flags & IEEE80211_CONF_IDLE)
                return 0;

        ieee80211_flush_queues(local, NULL);

        local->hw.conf.flags |= IEEE80211_CONF_IDLE;
        return IEEE80211_CONF_CHANGE_IDLE;
}

static u32 __ieee80211_recalc_idle(struct ieee80211_local *local,
                                   bool force_active)
{
        bool working = false, scanning, active;
        unsigned int led_trig_start = 0, led_trig_stop = 0;
        struct ieee80211_roc_work *roc;

        lockdep_assert_held(&local->mtx);

        active = force_active ||
                 !list_empty(&local->chanctx_list) ||
                 local->monitors;

        if (!local->ops->remain_on_channel) {
                list_for_each_entry(roc, &local->roc_list, list) {
                        working = true;
                        break;
                }
        }

        scanning = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
                   test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);

        if (working || scanning)
                led_trig_start |= IEEE80211_TPT_LEDTRIG_FL_WORK;
        else
                led_trig_stop |= IEEE80211_TPT_LEDTRIG_FL_WORK;

        if (active)
                led_trig_start |= IEEE80211_TPT_LEDTRIG_FL_CONNECTED;
        else
                led_trig_stop |= IEEE80211_TPT_LEDTRIG_FL_CONNECTED;

        ieee80211_mod_tpt_led_trig(local, led_trig_start, led_trig_stop);

        if (working || scanning || active)
                return __ieee80211_idle_off(local);
        return __ieee80211_idle_on(local);
}

u32 ieee80211_idle_off(struct ieee80211_local *local)
{
        return __ieee80211_recalc_idle(local, true);
}

void ieee80211_recalc_idle(struct ieee80211_local *local)
{
        u32 change = __ieee80211_recalc_idle(local, false);
        if (change)
                ieee80211_hw_config(local, change);
}

static int ieee80211_change_mtu(struct net_device *dev, int new_mtu)
{
        if (new_mtu < 256 || new_mtu > IEEE80211_MAX_DATA_LEN)
                return -EINVAL;

        dev->mtu = new_mtu;
        return 0;
}

static int ieee80211_verify_mac(struct ieee80211_sub_if_data *sdata, u8 *addr,
                                bool check_dup)
{
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_sub_if_data *iter;
        u64 new, mask, tmp;
        u8 *m;
        int ret = 0;

        if (is_zero_ether_addr(local->hw.wiphy->addr_mask))
                return 0;

        m = addr;
        new =   ((u64)m[0] << 5*8) | ((u64)m[1] << 4*8) |
                ((u64)m[2] << 3*8) | ((u64)m[3] << 2*8) |
                ((u64)m[4] << 1*8) | ((u64)m[5] << 0*8);

        m = local->hw.wiphy->addr_mask;
        mask =  ((u64)m[0] << 5*8) | ((u64)m[1] << 4*8) |
                ((u64)m[2] << 3*8) | ((u64)m[3] << 2*8) |
                ((u64)m[4] << 1*8) | ((u64)m[5] << 0*8);

        if (!check_dup)
                return ret;

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

                if (iter->vif.type == NL80211_IFTYPE_MONITOR &&
                    !(iter->u.mntr_flags & MONITOR_FLAG_ACTIVE))
                        continue;

                m = iter->vif.addr;
                tmp =   ((u64)m[0] << 5*8) | ((u64)m[1] << 4*8) |
                        ((u64)m[2] << 3*8) | ((u64)m[3] << 2*8) |
                        ((u64)m[4] << 1*8) | ((u64)m[5] << 0*8);

                if ((new & ~mask) != (tmp & ~mask)) {
                        ret = -EINVAL;
                        break;
                }
        }
        mutex_unlock(&local->iflist_mtx);

        return ret;
}

static int ieee80211_change_mac(struct net_device *dev, void *addr)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct sockaddr *sa = addr;
        bool check_dup = true;
        int ret;

        if (ieee80211_sdata_running(sdata))
                return -EBUSY;

        if (sdata->vif.type == NL80211_IFTYPE_MONITOR &&
            !(sdata->u.mntr_flags & MONITOR_FLAG_ACTIVE))
                check_dup = false;

        ret = ieee80211_verify_mac(sdata, sa->sa_data, check_dup);
        if (ret)
                return ret;

        ret = eth_mac_addr(dev, sa);

        if (ret == 0)
                memcpy(sdata->vif.addr, sa->sa_data, ETH_ALEN);

        return ret;
}

static inline int identical_mac_addr_allowed(int type1, int type2)
{
        return type1 == NL80211_IFTYPE_MONITOR ||
                type2 == NL80211_IFTYPE_MONITOR ||
                type1 == NL80211_IFTYPE_P2P_DEVICE ||
                type2 == NL80211_IFTYPE_P2P_DEVICE ||
                (type1 == NL80211_IFTYPE_AP && type2 == NL80211_IFTYPE_WDS) ||
                (type1 == NL80211_IFTYPE_WDS &&
                        (type2 == NL80211_IFTYPE_WDS ||
                         type2 == NL80211_IFTYPE_AP)) ||
                (type1 == NL80211_IFTYPE_AP && type2 == NL80211_IFTYPE_AP_VLAN) ||
                (type1 == NL80211_IFTYPE_AP_VLAN &&
                        (type2 == NL80211_IFTYPE_AP ||
                         type2 == NL80211_IFTYPE_AP_VLAN));
}

static int ieee80211_check_concurrent_iface(struct ieee80211_sub_if_data *sdata,
                                            enum nl80211_iftype iftype)
{
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_sub_if_data *nsdata;

        ASSERT_RTNL();

        /* we hold the RTNL here so can safely walk the list */
        list_for_each_entry(nsdata, &local->interfaces, list) {
                if (nsdata != sdata && ieee80211_sdata_running(nsdata)) {
                        /*
                         * Allow only a single IBSS interface to be up at any
                         * time. This is restricted because beacon distribution
                         * cannot work properly if both are in the same IBSS.
                         *
                         * To remove this restriction we'd have to disallow them
                         * from setting the same SSID on different IBSS interfaces
                         * belonging to the same hardware. Then, however, we're
                         * faced with having to adopt two different TSF timers...
                         */
                        if (iftype == NL80211_IFTYPE_ADHOC &&
                            nsdata->vif.type == NL80211_IFTYPE_ADHOC)
                                return -EBUSY;

                        /*
                         * The remaining checks are only performed for interfaces
                         * with the same MAC address.
                         */
                        if (!ether_addr_equal(sdata->vif.addr,
                                              nsdata->vif.addr))
                                continue;

                        /*
                         * check whether it may have the same address
                         */
                        if (!identical_mac_addr_allowed(iftype,
                                                        nsdata->vif.type))
                                return -ENOTUNIQ;

                        /*
                         * can only add VLANs to enabled APs
                         */
                        if (iftype == NL80211_IFTYPE_AP_VLAN &&
                            nsdata->vif.type == NL80211_IFTYPE_AP)
                                sdata->bss = &nsdata->u.ap;
                }
        }

        return 0;
}

static int ieee80211_check_queues(struct ieee80211_sub_if_data *sdata)
{
        int n_queues = sdata->local->hw.queues;
        int i;

        if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE) {
                for (i = 0; i < IEEE80211_NUM_ACS; i++) {
                        if (WARN_ON_ONCE(sdata->vif.hw_queue[i] ==
                                         IEEE80211_INVAL_HW_QUEUE))
                                return -EINVAL;
                        if (WARN_ON_ONCE(sdata->vif.hw_queue[i] >=
                                         n_queues))
                                return -EINVAL;
                }
        }

        if ((sdata->vif.type != NL80211_IFTYPE_AP &&
             sdata->vif.type != NL80211_IFTYPE_MESH_POINT) ||
            !(sdata->local->hw.flags & IEEE80211_HW_QUEUE_CONTROL)) {
                sdata->vif.cab_queue = IEEE80211_INVAL_HW_QUEUE;
                return 0;
        }

        if (WARN_ON_ONCE(sdata->vif.cab_queue == IEEE80211_INVAL_HW_QUEUE))
                return -EINVAL;

        if (WARN_ON_ONCE(sdata->vif.cab_queue >= n_queues))
                return -EINVAL;

        return 0;
}

void ieee80211_adjust_monitor_flags(struct ieee80211_sub_if_data *sdata,
                                    const int offset)
{
        struct ieee80211_local *local = sdata->local;
        u32 flags = sdata->u.mntr_flags;

#define ADJUST(_f, _s)  do {                                    \
        if (flags & MONITOR_FLAG_##_f)                          \
                local->fif_##_s += offset;                      \
        } while (0)

        ADJUST(FCSFAIL, fcsfail);
        ADJUST(PLCPFAIL, plcpfail);
        ADJUST(CONTROL, control);
        ADJUST(CONTROL, pspoll);
        ADJUST(OTHER_BSS, other_bss);

#undef ADJUST
}

static void ieee80211_set_default_queues(struct ieee80211_sub_if_data *sdata)
{
        struct ieee80211_local *local = sdata->local;
        int i;

        for (i = 0; i < IEEE80211_NUM_ACS; i++) {
                if (local->hw.flags & IEEE80211_HW_QUEUE_CONTROL)
                        sdata->vif.hw_queue[i] = IEEE80211_INVAL_HW_QUEUE;
                else if (local->hw.queues >= IEEE80211_NUM_ACS)
                        sdata->vif.hw_queue[i] = i;
                else
                        sdata->vif.hw_queue[i] = 0;
        }
        sdata->vif.cab_queue = IEEE80211_INVAL_HW_QUEUE;
}

int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
{
        struct ieee80211_sub_if_data *sdata;
        int ret;

        if (!(local->hw.flags & IEEE80211_HW_WANT_MONITOR_VIF))
                return 0;

        ASSERT_RTNL();

        if (local->monitor_sdata)
                return 0;

        sdata = kzalloc(sizeof(*sdata) + local->hw.vif_data_size, GFP_KERNEL);
        if (!sdata)
                return -ENOMEM;

        /* set up data */
        sdata->local = local;
        sdata->vif.type = NL80211_IFTYPE_MONITOR;
        snprintf(sdata->name, IFNAMSIZ, "%s-monitor",
                 wiphy_name(local->hw.wiphy));

        ieee80211_set_default_queues(sdata);

        ret = drv_add_interface(local, sdata);
        if (WARN_ON(ret)) {
                /* ok .. stupid driver, it asked for this! */
                kfree(sdata);
                return ret;
        }

        ret = ieee80211_check_queues(sdata);
        if (ret) {
                kfree(sdata);
                return ret;
        }

        ret = ieee80211_vif_use_channel(sdata, &local->monitor_chandef,
                                        IEEE80211_CHANCTX_EXCLUSIVE);
        if (ret) {
                drv_remove_interface(local, sdata);
                kfree(sdata);
                return ret;
        }

        mutex_lock(&local->iflist_mtx);
        rcu_assign_pointer(local->monitor_sdata, sdata);
        mutex_unlock(&local->iflist_mtx);

        return 0;
}

void ieee80211_del_virtual_monitor(struct ieee80211_local *local)
{
        struct ieee80211_sub_if_data *sdata;

        if (!(local->hw.flags & IEEE80211_HW_WANT_MONITOR_VIF))
                return;

        ASSERT_RTNL();

        mutex_lock(&local->iflist_mtx);

        sdata = rcu_dereference_protected(local->monitor_sdata,
                                          lockdep_is_held(&local->iflist_mtx));
        if (!sdata) {
                mutex_unlock(&local->iflist_mtx);
                return;
        }

        rcu_assign_pointer(local->monitor_sdata, NULL);
        mutex_unlock(&local->iflist_mtx);

        synchronize_net();

        ieee80211_vif_release_channel(sdata);

        drv_remove_interface(local, sdata);

        kfree(sdata);
}

/*
 * NOTE: Be very careful when changing this function, it must NOT return
 * an error on interface type changes that have been pre-checked, so most
 * checks should be in ieee80211_check_concurrent_iface.
 */
int ieee80211_do_open(struct wireless_dev *wdev, bool coming_up)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
        struct net_device *dev = wdev->netdev;
        struct ieee80211_local *local = sdata->local;
        struct sta_info *sta;
        u32 changed = 0;
        int res;
        u32 hw_reconf_flags = 0;

        switch (sdata->vif.type) {
        case NL80211_IFTYPE_WDS:
                if (!is_valid_ether_addr(sdata->u.wds.remote_addr))
                        return -ENOLINK;
                break;
        case NL80211_IFTYPE_AP_VLAN: {
                struct ieee80211_sub_if_data *master;

                if (!sdata->bss)
                        return -ENOLINK;

                list_add(&sdata->u.vlan.list, &sdata->bss->vlans);

                master = container_of(sdata->bss,
                                      struct ieee80211_sub_if_data, u.ap);
                sdata->control_port_protocol =
                        master->control_port_protocol;
                sdata->control_port_no_encrypt =
                        master->control_port_no_encrypt;
                sdata->vif.cab_queue = master->vif.cab_queue;
                memcpy(sdata->vif.hw_queue, master->vif.hw_queue,
                       sizeof(sdata->vif.hw_queue));
                break;
                }
        case NL80211_IFTYPE_AP:
                sdata->bss = &sdata->u.ap;
                break;
        case NL80211_IFTYPE_MESH_POINT:
        case NL80211_IFTYPE_STATION:
        case NL80211_IFTYPE_MONITOR:
        case NL80211_IFTYPE_ADHOC:
        case NL80211_IFTYPE_P2P_DEVICE:
                /* no special treatment */
                break;
        case NL80211_IFTYPE_UNSPECIFIED:
        case NUM_NL80211_IFTYPES:
        case NL80211_IFTYPE_P2P_CLIENT:
        case NL80211_IFTYPE_P2P_GO:
                /* cannot happen */
                WARN_ON(1);
                break;
        }

        if (local->open_count == 0) {
                res = drv_start(local);
                if (res)
                        goto err_del_bss;
                /* we're brought up, everything changes */
                hw_reconf_flags = ~0;
                ieee80211_led_radio(local, true);
                ieee80211_mod_tpt_led_trig(local,
                                           IEEE80211_TPT_LEDTRIG_FL_RADIO, 0);
        }

        /*
         * Copy the hopefully now-present MAC address to
         * this interface, if it has the special null one.
         */
        if (dev && is_zero_ether_addr(dev->dev_addr)) {
                memcpy(dev->dev_addr,
                       local->hw.wiphy->perm_addr,
                       ETH_ALEN);
                memcpy(dev->perm_addr, dev->dev_addr, ETH_ALEN);

                if (!is_valid_ether_addr(dev->dev_addr)) {
                        res = -EADDRNOTAVAIL;
                        goto err_stop;
                }
        }

        switch (sdata->vif.type) {
        case NL80211_IFTYPE_AP_VLAN:
                /* no need to tell driver, but set carrier and chanctx */
                if (rtnl_dereference(sdata->bss->beacon)) {
                        ieee80211_vif_vlan_copy_chanctx(sdata);
                        netif_carrier_on(dev);
                } else {
                        netif_carrier_off(dev);
                }
                break;
        case NL80211_IFTYPE_MONITOR:
                if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {
                        local->cooked_mntrs++;
                        break;
                }

                if (sdata->u.mntr_flags & MONITOR_FLAG_ACTIVE) {
                        res = drv_add_interface(local, sdata);
                        if (res)
                                goto err_stop;
                } else if (local->monitors == 0 && local->open_count == 0) {
                        res = ieee80211_add_virtual_monitor(local);
                        if (res)
                                goto err_stop;
                }

                /* must be before the call to ieee80211_configure_filter */
                local->monitors++;
                if (local->monitors == 1) {
                        local->hw.conf.flags |= IEEE80211_CONF_MONITOR;
                        hw_reconf_flags |= IEEE80211_CONF_CHANGE_MONITOR;
                }

                ieee80211_adjust_monitor_flags(sdata, 1);
                ieee80211_configure_filter(local);
                mutex_lock(&local->mtx);
                ieee80211_recalc_idle(local);
                mutex_unlock(&local->mtx);

                netif_carrier_on(dev);
                break;
        default:
                if (coming_up) {
                        ieee80211_del_virtual_monitor(local);

                        res = drv_add_interface(local, sdata);
                        if (res)
                                goto err_stop;
                        res = ieee80211_check_queues(sdata);
                        if (res)
                                goto err_del_interface;
                }

                if (sdata->vif.type == NL80211_IFTYPE_AP) {
                        local->fif_pspoll++;
                        local->fif_probe_req++;

                        ieee80211_configure_filter(local);
                } else if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
                        local->fif_probe_req++;
                }

                if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE)
                        changed |= ieee80211_reset_erp_info(sdata);
                ieee80211_bss_info_change_notify(sdata, changed);

                switch (sdata->vif.type) {
                case NL80211_IFTYPE_STATION:
                case NL80211_IFTYPE_ADHOC:
                case NL80211_IFTYPE_AP:
                case NL80211_IFTYPE_MESH_POINT:
                        netif_carrier_off(dev);
                        break;
                case NL80211_IFTYPE_WDS:
                case NL80211_IFTYPE_P2P_DEVICE:
                        break;
                default:
                        /* not reached */
                        WARN_ON(1);
                }

                /*
                 * set default queue parameters so drivers don't
                 * need to initialise the hardware if the hardware
                 * doesn't start up with sane defaults
                 */
                ieee80211_set_wmm_default(sdata, true);
        }

        set_bit(SDATA_STATE_RUNNING, &sdata->state);

        if (sdata->vif.type == NL80211_IFTYPE_WDS) {
                /* Create STA entry for the WDS peer */
                sta = sta_info_alloc(sdata, sdata->u.wds.remote_addr,
                                     GFP_KERNEL);
                if (!sta) {
                        res = -ENOMEM;
                        goto err_del_interface;
                }

                sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
                sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
                sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);

                res = sta_info_insert(sta);
                if (res) {
                        /* STA has been freed */
                        goto err_del_interface;
                }

                rate_control_rate_init(sta);
                netif_carrier_on(dev);
        } else if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE) {
                rcu_assign_pointer(local->p2p_sdata, sdata);
        }

        /*
         * set_multicast_list will be invoked by the networking core
         * which will check whether any increments here were done in
         * error and sync them down to the hardware as filter flags.
         */
        if (sdata->flags & IEEE80211_SDATA_ALLMULTI)
                atomic_inc(&local->iff_allmultis);

        if (sdata->flags & IEEE80211_SDATA_PROMISC)
                atomic_inc(&local->iff_promiscs);

        if (coming_up)
                local->open_count++;

        if (hw_reconf_flags)
                ieee80211_hw_config(local, hw_reconf_flags);

        ieee80211_recalc_ps(local, -1);

        if (sdata->vif.type == NL80211_IFTYPE_MONITOR ||
            sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
                /* XXX: for AP_VLAN, actually track AP queues */
                netif_tx_start_all_queues(dev);
        } else if (dev) {
                unsigned long flags;
                int n_acs = IEEE80211_NUM_ACS;
                int ac;

                if (local->hw.queues < IEEE80211_NUM_ACS)
                        n_acs = 1;

                spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
                if (sdata->vif.cab_queue == IEEE80211_INVAL_HW_QUEUE ||
                    (local->queue_stop_reasons[sdata->vif.cab_queue] == 0 &&
                     skb_queue_empty(&local->pending[sdata->vif.cab_queue]))) {
                        for (ac = 0; ac < n_acs; ac++) {
                                int ac_queue = sdata->vif.hw_queue[ac];

                                if (local->queue_stop_reasons[ac_queue] == 0 &&
                                    skb_queue_empty(&local->pending[ac_queue]))
                                        netif_start_subqueue(dev, ac);
                        }
                }
                spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
        }

        return 0;
 err_del_interface:
        drv_remove_interface(local, sdata);
 err_stop:
        if (!local->open_count)
                drv_stop(local);
 err_del_bss:
        sdata->bss = NULL;
        if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
                list_del(&sdata->u.vlan.list);
        /* might already be clear but that doesn't matter */
        clear_bit(SDATA_STATE_RUNNING, &sdata->state);
        return res;
}

static int ieee80211_open(struct net_device *dev)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        int err;

        /* fail early if user set an invalid address */
        if (!is_valid_ether_addr(dev->dev_addr))
                return -EADDRNOTAVAIL;

        err = ieee80211_check_concurrent_iface(sdata, sdata->vif.type);
        if (err)
                return err;

        return ieee80211_do_open(&sdata->wdev, true);
}

static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
                              bool going_down)
{
        struct ieee80211_local *local = sdata->local;
        unsigned long flags;
        struct sk_buff *skb, *tmp;
        u32 hw_reconf_flags = 0;
        int i, flushed;
        struct ps_data *ps;

        clear_bit(SDATA_STATE_RUNNING, &sdata->state);

        if (rcu_access_pointer(local->scan_sdata) == sdata)
                ieee80211_scan_cancel(local);

        /*
         * Stop TX on this interface first.
         */
        if (sdata->dev)
                netif_tx_stop_all_queues(sdata->dev);

        ieee80211_roc_purge(local, sdata);

        if (sdata->vif.type == NL80211_IFTYPE_STATION)
                ieee80211_mgd_stop(sdata);

        /*
         * Remove all stations associated with this interface.
         *
         * This must be done before calling ops->remove_interface()
         * because otherwise we can later invoke ops->sta_notify()
         * whenever the STAs are removed, and that invalidates driver
         * assumptions about always getting a vif pointer that is valid
         * (because if we remove a STA after ops->remove_interface()
         * the driver will have removed the vif info already!)
         *
         * This is relevant only in WDS mode, in all other modes we've
         * already removed all stations when disconnecting or similar,
         * so warn otherwise.
         *
         * We call sta_info_flush_cleanup() later, to combine RCU waits.
         */
        flushed = sta_info_flush_defer(sdata);
        WARN_ON_ONCE((sdata->vif.type != NL80211_IFTYPE_WDS && flushed > 0) ||
                     (sdata->vif.type == NL80211_IFTYPE_WDS && flushed != 1));

        /* don't count this interface for promisc/allmulti while it is down */
        if (sdata->flags & IEEE80211_SDATA_ALLMULTI)
                atomic_dec(&local->iff_allmultis);

        if (sdata->flags & IEEE80211_SDATA_PROMISC)
                atomic_dec(&local->iff_promiscs);

        if (sdata->vif.type == NL80211_IFTYPE_AP) {
                local->fif_pspoll--;
                local->fif_probe_req--;
        } else if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
                local->fif_probe_req--;
        }

        if (sdata->dev) {
                netif_addr_lock_bh(sdata->dev);
                spin_lock_bh(&local->filter_lock);
                __hw_addr_unsync(&local->mc_list, &sdata->dev->mc,
                                 sdata->dev->addr_len);
                spin_unlock_bh(&local->filter_lock);
                netif_addr_unlock_bh(sdata->dev);
        }

        del_timer_sync(&local->dynamic_ps_timer);
        cancel_work_sync(&local->dynamic_ps_enable_work);

        cancel_work_sync(&sdata->recalc_smps);

        cancel_delayed_work_sync(&sdata->dfs_cac_timer_work);

        if (sdata->wdev.cac_started) {
                WARN_ON(local->suspended);
                mutex_lock(&local->iflist_mtx);
                ieee80211_vif_release_channel(sdata);
                mutex_unlock(&local->iflist_mtx);
                cfg80211_cac_event(sdata->dev, NL80211_RADAR_CAC_ABORTED,
                                   GFP_KERNEL);
        }

        /* APs need special treatment */
        if (sdata->vif.type == NL80211_IFTYPE_AP) {
                struct ieee80211_sub_if_data *vlan, *tmpsdata;

                /* down all dependent devices, that is VLANs */
                list_for_each_entry_safe(vlan, tmpsdata, &sdata->u.ap.vlans,
                                         u.vlan.list)
                        dev_close(vlan->dev);
                WARN_ON(!list_empty(&sdata->u.ap.vlans));
        } else if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
                /* remove all packets in parent bc_buf pointing to this dev */
                ps = &sdata->bss->ps;

                spin_lock_irqsave(&ps->bc_buf.lock, flags);
                skb_queue_walk_safe(&ps->bc_buf, skb, tmp) {
                        if (skb->dev == sdata->dev) {
                                __skb_unlink(skb, &ps->bc_buf);
                                local->total_ps_buffered--;
                                ieee80211_free_txskb(&local->hw, skb);
                        }
                }
                spin_unlock_irqrestore(&ps->bc_buf.lock, flags);
        }

        if (going_down)
                local->open_count--;

        switch (sdata->vif.type) {
        case NL80211_IFTYPE_AP_VLAN:
                list_del(&sdata->u.vlan.list);
                rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
                /* no need to tell driver */
                break;
        case NL80211_IFTYPE_MONITOR:
                if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {
                        local->cooked_mntrs--;
                        break;
                }

                local->monitors--;
                if (local->monitors == 0) {
                        local->hw.conf.flags &= ~IEEE80211_CONF_MONITOR;
                        hw_reconf_flags |= IEEE80211_CONF_CHANGE_MONITOR;
                }

                ieee80211_adjust_monitor_flags(sdata, -1);
                break;
        case NL80211_IFTYPE_P2P_DEVICE:
                /* relies on synchronize_rcu() below */
                rcu_assign_pointer(local->p2p_sdata, NULL);
                /* fall through */
        default:
                cancel_work_sync(&sdata->work);
                /*
                 * When we get here, the interface is marked down.
                 *
                 * sta_info_flush_cleanup() requires rcu_barrier()
                 * first to wait for the station call_rcu() calls
                 * to complete, and we also need synchronize_rcu()
                 * to wait for the RX path in case it is using the
                 * interface and enqueuing frames at this very time on
                 * another CPU.
                 */
                synchronize_rcu();
                rcu_barrier();
                sta_info_flush_cleanup(sdata);

                /*
                 * Free all remaining keys, there shouldn't be any,
                 * except maybe in WDS mode?
                 */
                ieee80211_free_keys(sdata);

                /* fall through */
        case NL80211_IFTYPE_AP:
                skb_queue_purge(&sdata->skb_queue);
        }

        sdata->bss = NULL;

        spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
        for (i = 0; i < IEEE80211_MAX_QUEUES; i++) {
                skb_queue_walk_safe(&local->pending[i], skb, tmp) {
                        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
                        if (info->control.vif == &sdata->vif) {
                                __skb_unlink(skb, &local->pending[i]);
                                ieee80211_free_txskb(&local->hw, skb);
                        }
                }
        }
        spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);

        if (local->open_count == 0)
                ieee80211_clear_tx_pending(local);

        /*
         * If the interface goes down while suspended, presumably because
         * the device was unplugged and that happens before our resume,
         * then the driver is already unconfigured and the remainder of
         * this function isn't needed.
         * XXX: what about WoWLAN? If the device has software state, e.g.
         *      memory allocated, it might expect teardown commands from
         *      mac80211 here?
         */
        if (local->suspended) {
                WARN_ON(local->wowlan);
                WARN_ON(rtnl_dereference(local->monitor_sdata));
                return;
        }

        switch (sdata->vif.type) {
        case NL80211_IFTYPE_AP_VLAN:
                break;
        case NL80211_IFTYPE_MONITOR:
                if (local->monitors == 0)
                        ieee80211_del_virtual_monitor(local);

                mutex_lock(&local->mtx);
                ieee80211_recalc_idle(local);
                mutex_unlock(&local->mtx);

                if (!(sdata->u.mntr_flags & MONITOR_FLAG_ACTIVE))
                        break;

                /* fall through */
        default:
                if (going_down)
                        drv_remove_interface(local, sdata);
        }

        ieee80211_recalc_ps(local, -1);

        if (local->open_count == 0) {
                ieee80211_stop_device(local);

                /* no reconfiguring after stop! */
                return;
        }

        /* do after stop to avoid reconfiguring when we stop anyway */
        ieee80211_configure_filter(local);
        ieee80211_hw_config(local, hw_reconf_flags);

        if (local->monitors == local->open_count)
                ieee80211_add_virtual_monitor(local);
}

static int ieee80211_stop(struct net_device *dev)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);

        ieee80211_do_stop(sdata, true);

        return 0;
}

static void ieee80211_set_multicast_list(struct net_device *dev)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct ieee80211_local *local = sdata->local;
        int allmulti, promisc, sdata_allmulti, sdata_promisc;

        allmulti = !!(dev->flags & IFF_ALLMULTI);
        promisc = !!(dev->flags & IFF_PROMISC);
        sdata_allmulti = !!(sdata->flags & IEEE80211_SDATA_ALLMULTI);
        sdata_promisc = !!(sdata->flags & IEEE80211_SDATA_PROMISC);

        if (allmulti != sdata_allmulti) {
                if (dev->flags & IFF_ALLMULTI)
                        atomic_inc(&local->iff_allmultis);
                else
                        atomic_dec(&local->iff_allmultis);
                sdata->flags ^= IEEE80211_SDATA_ALLMULTI;
        }

        if (promisc != sdata_promisc) {
                if (dev->flags & IFF_PROMISC)
                        atomic_inc(&local->iff_promiscs);
                else
                        atomic_dec(&local->iff_promiscs);
                sdata->flags ^= IEEE80211_SDATA_PROMISC;
        }

        /*
         * TODO: If somebody needs this on AP interfaces,
         *       it can be enabled easily but multicast
         *       addresses from VLANs need to be synced.
         */
        if (sdata->vif.type != NL80211_IFTYPE_MONITOR &&
            sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
            sdata->vif.type != NL80211_IFTYPE_AP)
                drv_set_multicast_list(local, sdata, &dev->mc);

        spin_lock_bh(&local->filter_lock);
        __hw_addr_sync(&local->mc_list, &dev->mc, dev->addr_len);
        spin_unlock_bh(&local->filter_lock);
        ieee80211_queue_work(&local->hw, &local->reconfig_filter);
}

/*
 * Called when the netdev is removed or, by the code below, before
 * the interface type changes.
 */
static void ieee80211_teardown_sdata(struct ieee80211_sub_if_data *sdata)
{
        int flushed;
        int i;

        /* free extra data */
        ieee80211_free_keys(sdata);

        ieee80211_debugfs_remove_netdev(sdata);

        for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++)
                __skb_queue_purge(&sdata->fragments[i].skb_list);
        sdata->fragment_next = 0;

        if (ieee80211_vif_is_mesh(&sdata->vif))
                mesh_rmc_free(sdata);

        flushed = sta_info_flush(sdata);
        WARN_ON(flushed);
}

static void ieee80211_uninit(struct net_device *dev)
{
        ieee80211_teardown_sdata(IEEE80211_DEV_TO_SUB_IF(dev));
}

static u16 ieee80211_netdev_select_queue(struct net_device *dev,
                                         struct sk_buff *skb)
{
        return ieee80211_select_queue(IEEE80211_DEV_TO_SUB_IF(dev), skb);
}

static const struct net_device_ops ieee80211_dataif_ops = {
        .ndo_open               = ieee80211_open,
        .ndo_stop               = ieee80211_stop,
        .ndo_uninit             = ieee80211_uninit,
        .ndo_start_xmit         = ieee80211_subif_start_xmit,
        .ndo_set_rx_mode        = ieee80211_set_multicast_list,
        .ndo_change_mtu         = ieee80211_change_mtu,
        .ndo_set_mac_address    = ieee80211_change_mac,
        .ndo_select_queue       = ieee80211_netdev_select_queue,
};

static u16 ieee80211_monitor_select_queue(struct net_device *dev,
                                          struct sk_buff *skb)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_hdr *hdr;
        struct ieee80211_radiotap_header *rtap = (void *)skb->data;

        if (local->hw.queues < IEEE80211_NUM_ACS)
                return 0;

        if (skb->len < 4 ||
            skb->len < le16_to_cpu(rtap->it_len) + 2 /* frame control */)
                return 0; /* doesn't matter, frame will be dropped */

        hdr = (void *)((u8 *)skb->data + le16_to_cpu(rtap->it_len));

        return ieee80211_select_queue_80211(sdata, skb, hdr);
}

static const struct net_device_ops ieee80211_monitorif_ops = {
        .ndo_open               = ieee80211_open,
        .ndo_stop               = ieee80211_stop,
        .ndo_uninit             = ieee80211_uninit,
        .ndo_start_xmit         = ieee80211_monitor_start_xmit,
        .ndo_set_rx_mode        = ieee80211_set_multicast_list,
        .ndo_change_mtu         = ieee80211_change_mtu,
        .ndo_set_mac_address    = ieee80211_change_mac,
        .ndo_select_queue       = ieee80211_monitor_select_queue,
};

static void ieee80211_if_setup(struct net_device *dev)
{
        ether_setup(dev);
        dev->priv_flags &= ~IFF_TX_SKB_SHARING;
        dev->netdev_ops = &ieee80211_dataif_ops;
        dev->destructor = free_netdev;
}

static void ieee80211_iface_work(struct work_struct *work)
{
        struct ieee80211_sub_if_data *sdata =
                container_of(work, struct ieee80211_sub_if_data, work);
        struct ieee80211_local *local = sdata->local;
        struct sk_buff *skb;
        struct sta_info *sta;
        struct ieee80211_ra_tid *ra_tid;

        if (!ieee80211_sdata_running(sdata))
                return;

        if (local->scanning)
                return;

        /*
         * ieee80211_queue_work() should have picked up most cases,
         * here we'll pick the rest.
         */
        if (WARN(local->suspended,
                 "interface work scheduled while going to suspend\n"))
                return;

        /* first process frames */
        while ((skb = skb_dequeue(&sdata->skb_queue))) {
                struct ieee80211_mgmt *mgmt = (void *)skb->data;

                if (skb->pkt_type == IEEE80211_SDATA_QUEUE_AGG_START) {
                        ra_tid = (void *)&skb->cb;
                        ieee80211_start_tx_ba_cb(&sdata->vif, ra_tid->ra,
                                                 ra_tid->tid);
                } else if (skb->pkt_type == IEEE80211_SDATA_QUEUE_AGG_STOP) {
                        ra_tid = (void *)&skb->cb;
                        ieee80211_stop_tx_ba_cb(&sdata->vif, ra_tid->ra,
                                                ra_tid->tid);
                } else if (ieee80211_is_action(mgmt->frame_control) &&
                           mgmt->u.action.category == WLAN_CATEGORY_BACK) {
                        int len = skb->len;

                        mutex_lock(&local->sta_mtx);
                        sta = sta_info_get_bss(sdata, mgmt->sa);
                        if (sta) {
                                switch (mgmt->u.action.u.addba_req.action_code) {
                                case WLAN_ACTION_ADDBA_REQ:
                                        ieee80211_process_addba_request(
                                                        local, sta, mgmt, len);
                                        break;
                                case WLAN_ACTION_ADDBA_RESP:
                                        ieee80211_process_addba_resp(local, sta,
                                                                     mgmt, len);
                                        break;
                                case WLAN_ACTION_DELBA:
                                        ieee80211_process_delba(sdata, sta,
                                                                mgmt, len);
                                        break;
                                default:
                                        WARN_ON(1);
                                        break;
                                }
                        }
                        mutex_unlock(&local->sta_mtx);
                } else if (ieee80211_is_data_qos(mgmt->frame_control)) {
                        struct ieee80211_hdr *hdr = (void *)mgmt;
                        /*
                         * So the frame isn't mgmt, but frame_control
                         * is at the right place anyway, of course, so
                         * the if statement is correct.
                         *
                         * Warn if we have other data frame types here,
                         * they must not get here.
                         */
                        WARN_ON(hdr->frame_control &
                                        cpu_to_le16(IEEE80211_STYPE_NULLFUNC));
                        WARN_ON(!(hdr->seq_ctrl &
                                        cpu_to_le16(IEEE80211_SCTL_FRAG)));
                        /*
                         * This was a fragment of a frame, received while
                         * a block-ack session was active. That cannot be
                         * right, so terminate the session.
                         */
                        mutex_lock(&local->sta_mtx);
                        sta = sta_info_get_bss(sdata, mgmt->sa);
                        if (sta) {
                                u16 tid = *ieee80211_get_qos_ctl(hdr) &
                                                IEEE80211_QOS_CTL_TID_MASK;

                                __ieee80211_stop_rx_ba_session(
                                        sta, tid, WLAN_BACK_RECIPIENT,
                                        WLAN_REASON_QSTA_REQUIRE_SETUP,
                                        true);
                        }
                        mutex_unlock(&local->sta_mtx);
                } else switch (sdata->vif.type) {
                case NL80211_IFTYPE_STATION:
                        ieee80211_sta_rx_queued_mgmt(sdata, skb);
                        break;
                case NL80211_IFTYPE_ADHOC:
                        ieee80211_ibss_rx_queued_mgmt(sdata, skb);
                        break;
                case NL80211_IFTYPE_MESH_POINT:
                        if (!ieee80211_vif_is_mesh(&sdata->vif))
                                break;
                        ieee80211_mesh_rx_queued_mgmt(sdata, skb);
                        break;
                default:
                        WARN(1, "frame for unexpected interface type");
                        break;
                }

                kfree_skb(skb);
        }

        /* then other type-dependent work */
        switch (sdata->vif.type) {
        case NL80211_IFTYPE_STATION:
                ieee80211_sta_work(sdata);
                break;
        case NL80211_IFTYPE_ADHOC:
                ieee80211_ibss_work(sdata);
                break;
        case NL80211_IFTYPE_MESH_POINT:
                if (!ieee80211_vif_is_mesh(&sdata->vif))
                        break;
                ieee80211_mesh_work(sdata);
                break;
        default:
                break;
        }
}

static void ieee80211_recalc_smps_work(struct work_struct *work)
{
        struct ieee80211_sub_if_data *sdata =
                container_of(work, struct ieee80211_sub_if_data, recalc_smps);

        ieee80211_recalc_smps(sdata);
}

/*
 * Helper function to initialise an interface to a specific type.
 */
static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata,
                                  enum nl80211_iftype type)
{
        /* clear type-dependent union */
        memset(&sdata->u, 0, sizeof(sdata->u));

        /* and set some type-dependent values */
        sdata->vif.type = type;
        sdata->vif.p2p = false;
        sdata->wdev.iftype = type;

        sdata->control_port_protocol = cpu_to_be16(ETH_P_PAE);
        sdata->control_port_no_encrypt = false;

        sdata->noack_map = 0;

        /* only monitor/p2p-device differ */
        if (sdata->dev) {
                sdata->dev->netdev_ops = &ieee80211_dataif_ops;
                sdata->dev->type = ARPHRD_ETHER;
        }

        skb_queue_head_init(&sdata->skb_queue);
        INIT_WORK(&sdata->work, ieee80211_iface_work);
        INIT_WORK(&sdata->recalc_smps, ieee80211_recalc_smps_work);

        switch (type) {
        case NL80211_IFTYPE_P2P_GO:
                type = NL80211_IFTYPE_AP;
                sdata->vif.type = type;
                sdata->vif.p2p = true;
                /* fall through */
        case NL80211_IFTYPE_AP:
                skb_queue_head_init(&sdata->u.ap.ps.bc_buf);
                INIT_LIST_HEAD(&sdata->u.ap.vlans);
                sdata->vif.bss_conf.bssid = sdata->vif.addr;
                break;
        case NL80211_IFTYPE_P2P_CLIENT:
                type = NL80211_IFTYPE_STATION;
                sdata->vif.type = type;
                sdata->vif.p2p = true;
                /* fall through */
        case NL80211_IFTYPE_STATION:
                sdata->vif.bss_conf.bssid = sdata->u.mgd.bssid;
                ieee80211_sta_setup_sdata(sdata);
                break;
        case NL80211_IFTYPE_ADHOC:
                sdata->vif.bss_conf.bssid = sdata->u.ibss.bssid;
                ieee80211_ibss_setup_sdata(sdata);
                break;
        case NL80211_IFTYPE_MESH_POINT:
                if (ieee80211_vif_is_mesh(&sdata->vif))
                        ieee80211_mesh_init_sdata(sdata);
                break;
        case NL80211_IFTYPE_MONITOR:
                sdata->dev->type = ARPHRD_IEEE80211_RADIOTAP;
                sdata->dev->netdev_ops = &ieee80211_monitorif_ops;
                sdata->u.mntr_flags = MONITOR_FLAG_CONTROL |
                                      MONITOR_FLAG_OTHER_BSS;
                break;
        case NL80211_IFTYPE_WDS:
                sdata->vif.bss_conf.bssid = NULL;
                break;
        case NL80211_IFTYPE_AP_VLAN:
                break;
        case NL80211_IFTYPE_P2P_DEVICE:
                sdata->vif.bss_conf.bssid = sdata->vif.addr;
                break;
        case NL80211_IFTYPE_UNSPECIFIED:
        case NUM_NL80211_IFTYPES:
                BUG();
                break;
        }

        ieee80211_debugfs_add_netdev(sdata);
}

static int ieee80211_runtime_change_iftype(struct ieee80211_sub_if_data *sdata,
                                           enum nl80211_iftype type)
{
        struct ieee80211_local *local = sdata->local;
        int ret, err;
        enum nl80211_iftype internal_type = type;
        bool p2p = false;

        ASSERT_RTNL();

        if (!local->ops->change_interface)
                return -EBUSY;

        switch (sdata->vif.type) {
        case NL80211_IFTYPE_AP:
        case NL80211_IFTYPE_STATION:
        case NL80211_IFTYPE_ADHOC:
                /*
                 * Could maybe also all others here?
                 * Just not sure how that interacts
                 * with the RX/config path e.g. for
                 * mesh.
                 */
                break;
        default:
                return -EBUSY;
        }

        switch (type) {
        case NL80211_IFTYPE_AP:
        case NL80211_IFTYPE_STATION:
        case NL80211_IFTYPE_ADHOC:
                /*
                 * Could probably support everything
                 * but WDS here (WDS do_open can fail
                 * under memory pressure, which this
                 * code isn't prepared to handle).
                 */
                break;
        case NL80211_IFTYPE_P2P_CLIENT:
                p2p = true;
                internal_type = NL80211_IFTYPE_STATION;
                break;
        case NL80211_IFTYPE_P2P_GO:
                p2p = true;
                internal_type = NL80211_IFTYPE_AP;
                break;
        default:
                return -EBUSY;
        }

        ret = ieee80211_check_concurrent_iface(sdata, internal_type);
        if (ret)
                return ret;

        ieee80211_do_stop(sdata, false);

        ieee80211_teardown_sdata(sdata);

        ret = drv_change_interface(local, sdata, internal_type, p2p);
        if (ret)
                type = sdata->vif.type;

        /*
         * Ignore return value here, there's not much we can do since
         * the driver changed the interface type internally already.
         * The warnings will hopefully make driver authors fix it :-)
         */
        ieee80211_check_queues(sdata);

        ieee80211_setup_sdata(sdata, type);

        err = ieee80211_do_open(&sdata->wdev, false);
        WARN(err, "type change: do_open returned %d", err);

        return ret;
}

int ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
                             enum nl80211_iftype type)
{
        int ret;

        ASSERT_RTNL();

        if (type == ieee80211_vif_type_p2p(&sdata->vif))
                return 0;

        if (ieee80211_sdata_running(sdata)) {
                ret = ieee80211_runtime_change_iftype(sdata, type);
                if (ret)
                        return ret;
        } else {
                /* Purge and reset type-dependent state. */
                ieee80211_teardown_sdata(sdata);
                ieee80211_setup_sdata(sdata, type);
        }

        /* reset some values that shouldn't be kept across type changes */
        sdata->drop_unencrypted = 0;
        if (type == NL80211_IFTYPE_STATION)
                sdata->u.mgd.use_4addr = false;

        return 0;
}

static void ieee80211_assign_perm_addr(struct ieee80211_local *local,
                                       u8 *perm_addr, enum nl80211_iftype type)
{
        struct ieee80211_sub_if_data *sdata;
        u64 mask, start, addr, val, inc;
        u8 *m;
        u8 tmp_addr[ETH_ALEN];
        int i;

        /* default ... something at least */
        memcpy(perm_addr, local->hw.wiphy->perm_addr, ETH_ALEN);

        if (is_zero_ether_addr(local->hw.wiphy->addr_mask) &&
            local->hw.wiphy->n_addresses <= 1)
                return;

        mutex_lock(&local->iflist_mtx);

        switch (type) {
        case NL80211_IFTYPE_MONITOR:
                /* doesn't matter */
                break;
        case NL80211_IFTYPE_WDS:
        case NL80211_IFTYPE_AP_VLAN:
                /* match up with an AP interface */
                list_for_each_entry(sdata, &local->interfaces, list) {
                        if (sdata->vif.type != NL80211_IFTYPE_AP)
                                continue;
                        memcpy(perm_addr, sdata->vif.addr, ETH_ALEN);
                        break;
                }
                /* keep default if no AP interface present */
                break;
        case NL80211_IFTYPE_P2P_CLIENT:
        case NL80211_IFTYPE_P2P_GO:
                if (local->hw.flags & IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF) {
                        list_for_each_entry(sdata, &local->interfaces, list) {
                                if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE)
                                        continue;
                                if (!ieee80211_sdata_running(sdata))
                                        continue;
                                memcpy(perm_addr, sdata->vif.addr, ETH_ALEN);
                                goto out_unlock;
                        }
                }
                /* otherwise fall through */
        default:
                /* assign a new address if possible -- try n_addresses first */
                for (i = 0; i < local->hw.wiphy->n_addresses; i++) {
                        bool used = false;

                        list_for_each_entry(sdata, &local->interfaces, list) {
                                if (memcmp(local->hw.wiphy->addresses[i].addr,
                                           sdata->vif.addr, ETH_ALEN) == 0) {
                                        used = true;
                                        break;
                                }
                        }

                        if (!used) {
                                memcpy(perm_addr,
                                       local->hw.wiphy->addresses[i].addr,
                                       ETH_ALEN);
                                break;
                        }
                }

                /* try mask if available */
                if (is_zero_ether_addr(local->hw.wiphy->addr_mask))
                        break;

                m = local->hw.wiphy->addr_mask;
                mask =  ((u64)m[0] << 5*8) | ((u64)m[1] << 4*8) |
                        ((u64)m[2] << 3*8) | ((u64)m[3] << 2*8) |
                        ((u64)m[4] << 1*8) | ((u64)m[5] << 0*8);

                if (__ffs64(mask) + hweight64(mask) != fls64(mask)) {
                        /* not a contiguous mask ... not handled now! */
                        pr_info("not contiguous\n");
                        break;
                }

                /*
                 * Pick address of existing interface in case user changed
                 * MAC address manually, default to perm_addr.
                 */
                m = local->hw.wiphy->perm_addr;
                list_for_each_entry(sdata, &local->interfaces, list) {
                        if (sdata->vif.type == NL80211_IFTYPE_MONITOR)
                                continue;
                        m = sdata->vif.addr;
                        break;
                }
                start = ((u64)m[0] << 5*8) | ((u64)m[1] << 4*8) |
                        ((u64)m[2] << 3*8) | ((u64)m[3] << 2*8) |
                        ((u64)m[4] << 1*8) | ((u64)m[5] << 0*8);

                inc = 1ULL<<__ffs64(mask);
                val = (start & mask);
                addr = (start & ~mask) | (val & mask);
                do {
                        bool used = false;

                        tmp_addr[5] = addr >> 0*8;
                        tmp_addr[4] = addr >> 1*8;
                        tmp_addr[3] = addr >> 2*8;
                        tmp_addr[2] = addr >> 3*8;
                        tmp_addr[1] = addr >> 4*8;
                        tmp_addr[0] = addr >> 5*8;

                        val += inc;

                        list_for_each_entry(sdata, &local->interfaces, list) {
                                if (memcmp(tmp_addr, sdata->vif.addr,
                                                        ETH_ALEN) == 0) {
                                        used = true;
                                        break;
                                }
                        }

                        if (!used) {
                                memcpy(perm_addr, tmp_addr, ETH_ALEN);
                                break;
                        }
                        addr = (start & ~mask) | (val & mask);
                } while (addr != start);

                break;
        }

 out_unlock:
        mutex_unlock(&local->iflist_mtx);
}

static void ieee80211_cleanup_sdata_stas_wk(struct work_struct *wk)
{
        struct ieee80211_sub_if_data *sdata;

        sdata = container_of(wk, struct ieee80211_sub_if_data, cleanup_stations_wk);

        ieee80211_cleanup_sdata_stas(sdata);
}

int ieee80211_if_add(struct ieee80211_local *local, const char *name,
                     struct wireless_dev **new_wdev, enum nl80211_iftype type,
                     struct vif_params *params)
{
        struct net_device *ndev = NULL;
        struct ieee80211_sub_if_data *sdata = NULL;
        int ret, i;
        int txqs = 1;

        ASSERT_RTNL();

        if (type == NL80211_IFTYPE_P2P_DEVICE) {
                struct wireless_dev *wdev;

                sdata = kzalloc(sizeof(*sdata) + local->hw.vif_data_size,
                                GFP_KERNEL);
                if (!sdata)
                        return -ENOMEM;
                wdev = &sdata->wdev;

                sdata->dev = NULL;
                strlcpy(sdata->name, name, IFNAMSIZ);
                ieee80211_assign_perm_addr(local, wdev->address, type);
                memcpy(sdata->vif.addr, wdev->address, ETH_ALEN);
        } else {
                if (local->hw.queues >= IEEE80211_NUM_ACS)
                        txqs = IEEE80211_NUM_ACS;

                ndev = alloc_netdev_mqs(sizeof(*sdata) +
                                        local->hw.vif_data_size,
                                        name, ieee80211_if_setup, txqs, 1);
                if (!ndev)
                        return -ENOMEM;
                dev_net_set(ndev, wiphy_net(local->hw.wiphy));

                ndev->needed_headroom = local->tx_headroom +
                                        4*6 /* four MAC addresses */
                                        + 2 + 2 + 2 + 2 /* ctl, dur, seq, qos */
                                        + 6 /* mesh */
                                        + 8 /* rfc1042/bridge tunnel */
                                        - ETH_HLEN /* ethernet hard_header_len */
                                        + IEEE80211_ENCRYPT_HEADROOM;
                ndev->needed_tailroom = IEEE80211_ENCRYPT_TAILROOM;

                ret = dev_alloc_name(ndev, ndev->name);
                if (ret < 0) {
                        free_netdev(ndev);
                        return ret;
                }

                ieee80211_assign_perm_addr(local, ndev->perm_addr, type);
                memcpy(ndev->dev_addr, ndev->perm_addr, ETH_ALEN);
                SET_NETDEV_DEV(ndev, wiphy_dev(local->hw.wiphy));

                /* don't use IEEE80211_DEV_TO_SUB_IF -- it checks too much */
                sdata = netdev_priv(ndev);
                ndev->ieee80211_ptr = &sdata->wdev;
                memcpy(sdata->vif.addr, ndev->dev_addr, ETH_ALEN);
                memcpy(sdata->name, ndev->name, IFNAMSIZ);

                sdata->dev = ndev;
        }

        /* initialise type-independent data */
        sdata->wdev.wiphy = local->hw.wiphy;
        sdata->local = local;

        for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++)
                skb_queue_head_init(&sdata->fragments[i].skb_list);

        INIT_LIST_HEAD(&sdata->key_list);

        spin_lock_init(&sdata->cleanup_stations_lock);
        INIT_LIST_HEAD(&sdata->cleanup_stations);
        INIT_WORK(&sdata->cleanup_stations_wk, ieee80211_cleanup_sdata_stas_wk);
        INIT_DELAYED_WORK(&sdata->dfs_cac_timer_work,
                          ieee80211_dfs_cac_timer_work);
        INIT_DELAYED_WORK(&sdata->dec_tailroom_needed_wk,
                          ieee80211_delayed_tailroom_dec);

        for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
                struct ieee80211_supported_band *sband;
                sband = local->hw.wiphy->bands[i];
                sdata->rc_rateidx_mask[i] =
                        sband ? (1 << sband->n_bitrates) - 1 : 0;
                if (sband)
                        memcpy(sdata->rc_rateidx_mcs_mask[i],
                               sband->ht_cap.mcs.rx_mask,
                               sizeof(sdata->rc_rateidx_mcs_mask[i]));
                else
                        memset(sdata->rc_rateidx_mcs_mask[i], 0,
                               sizeof(sdata->rc_rateidx_mcs_mask[i]));
        }

        ieee80211_set_default_queues(sdata);

        sdata->ap_power_level = IEEE80211_UNSET_POWER_LEVEL;
        sdata->user_power_level = local->user_power_level;

        /* setup type-dependent data */
        ieee80211_setup_sdata(sdata, type);

        if (ndev) {
                if (params) {
                        ndev->ieee80211_ptr->use_4addr = params->use_4addr;
                        if (type == NL80211_IFTYPE_STATION)
                                sdata->u.mgd.use_4addr = params->use_4addr;
                }

                ndev->features |= local->hw.netdev_features;

                ret = register_netdevice(ndev);
                if (ret) {
                        free_netdev(ndev);
                        return ret;
                }
        }

        mutex_lock(&local->iflist_mtx);
        list_add_tail_rcu(&sdata->list, &local->interfaces);
        mutex_unlock(&local->iflist_mtx);

        if (new_wdev)
                *new_wdev = &sdata->wdev;

        return 0;
}

void ieee80211_if_remove(struct ieee80211_sub_if_data *sdata)
{
        ASSERT_RTNL();

        mutex_lock(&sdata->local->iflist_mtx);
        list_del_rcu(&sdata->list);
        mutex_unlock(&sdata->local->iflist_mtx);

        synchronize_rcu();

        if (sdata->dev) {
                unregister_netdevice(sdata->dev);
        } else {
                cfg80211_unregister_wdev(&sdata->wdev);
                kfree(sdata);
        }
}

void ieee80211_sdata_stop(struct ieee80211_sub_if_data *sdata)
{
        if (WARN_ON_ONCE(!test_bit(SDATA_STATE_RUNNING, &sdata->state)))
                return;
        ieee80211_do_stop(sdata, true);
        ieee80211_teardown_sdata(sdata);
}

/*
 * Remove all interfaces, may only be called at hardware unregistration
 * time because it doesn't do RCU-safe list removals.
 */
void ieee80211_remove_interfaces(struct ieee80211_local *local)
{
        struct ieee80211_sub_if_data *sdata, *tmp;
        LIST_HEAD(unreg_list);
        LIST_HEAD(wdev_list);

        ASSERT_RTNL();

        /*
         * Close all AP_VLAN interfaces first, as otherwise they
         * might be closed while the AP interface they belong to
         * is closed, causing unregister_netdevice_many() to crash.
         */
        list_for_each_entry(sdata, &local->interfaces, list)
                if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
                        dev_close(sdata->dev);

        mutex_lock(&local->iflist_mtx);
        list_for_each_entry_safe(sdata, tmp, &local->interfaces, list) {
                list_del(&sdata->list);

                if (sdata->dev)
                        unregister_netdevice_queue(sdata->dev, &unreg_list);
                else
                        list_add(&sdata->list, &wdev_list);
        }
        mutex_unlock(&local->iflist_mtx);
        unregister_netdevice_many(&unreg_list);
        list_del(&unreg_list);

        list_for_each_entry_safe(sdata, tmp, &wdev_list, list) {
                list_del(&sdata->list);
                cfg80211_unregister_wdev(&sdata->wdev);
                kfree(sdata);
        }
}

static int netdev_notify(struct notifier_block *nb,
                         unsigned long state, void *ptr)
{
        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
        struct ieee80211_sub_if_data *sdata;

        if (state != NETDEV_CHANGENAME)
                return 0;

        if (!dev->ieee80211_ptr || !dev->ieee80211_ptr->wiphy)
                return 0;

        if (dev->ieee80211_ptr->wiphy->privid != mac80211_wiphy_privid)
                return 0;

        sdata = IEEE80211_DEV_TO_SUB_IF(dev);

        memcpy(sdata->name, dev->name, IFNAMSIZ);

        ieee80211_debugfs_rename_netdev(sdata);
        return 0;
}

static struct notifier_block mac80211_netdev_notifier = {
        .notifier_call = netdev_notify,
};

int ieee80211_iface_init(void)
{
        return register_netdevice_notifier(&mac80211_netdev_notifier);
}

void ieee80211_iface_exit(void)
{
        unregister_netdevice_notifier(&mac80211_netdev_notifier);
}