/*
 * This is the linux wireless configuration interface.
 *
 * Copyright 2006-2010          Johannes Berg <johannes@sipsolutions.net>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/if.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/nl80211.h>
#include <linux/debugfs.h>
#include <linux/notifier.h>
#include <linux/device.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <linux/sched.h>
#include <net/genetlink.h>
#include <net/cfg80211.h>
#include "nl80211.h"
#include "core.h"
#include "sysfs.h"
#include "debugfs.h"
#include "wext-compat.h"
#include "ethtool.h"

/* name for sysfs, %d is appended */
#define PHY_NAME "phy"

MODULE_AUTHOR("Johannes Berg");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("wireless configuration support");

/* RCU-protected (and cfg80211_mutex for writers) */
LIST_HEAD(cfg80211_rdev_list);
int cfg80211_rdev_list_generation;

DEFINE_MUTEX(cfg80211_mutex);

/* for debugfs */
static struct dentry *ieee80211_debugfs_dir;

/* for the cleanup, scan and event works */
struct workqueue_struct *cfg80211_wq;

static bool cfg80211_disable_40mhz_24ghz;
module_param(cfg80211_disable_40mhz_24ghz, bool, 0644);
MODULE_PARM_DESC(cfg80211_disable_40mhz_24ghz,
                 "Disable 40MHz support in the 2.4GHz band");

/* requires cfg80211_mutex to be held! */
struct cfg80211_registered_device *cfg80211_rdev_by_wiphy_idx(int wiphy_idx)
{
        struct cfg80211_registered_device *result = NULL, *rdev;

        if (!wiphy_idx_valid(wiphy_idx))
                return NULL;

        assert_cfg80211_lock();

        list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
                if (rdev->wiphy_idx == wiphy_idx) {
                        result = rdev;
                        break;
                }
        }

        return result;
}

int get_wiphy_idx(struct wiphy *wiphy)
{
        struct cfg80211_registered_device *rdev;
        if (!wiphy)
                return WIPHY_IDX_STALE;
        rdev = wiphy_to_dev(wiphy);
        return rdev->wiphy_idx;
}

/* requires cfg80211_rdev_mutex to be held! */
struct wiphy *wiphy_idx_to_wiphy(int wiphy_idx)
{
        struct cfg80211_registered_device *rdev;

        if (!wiphy_idx_valid(wiphy_idx))
                return NULL;

        assert_cfg80211_lock();

        rdev = cfg80211_rdev_by_wiphy_idx(wiphy_idx);
        if (!rdev)
                return NULL;
        return &rdev->wiphy;
}

struct cfg80211_registered_device *
cfg80211_get_dev_from_ifindex(struct net *net, int ifindex)
{
        struct cfg80211_registered_device *rdev = ERR_PTR(-ENODEV);
        struct net_device *dev;

        mutex_lock(&cfg80211_mutex);
        dev = dev_get_by_index(net, ifindex);
        if (!dev)
                goto out;
        if (dev->ieee80211_ptr) {
                rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
                mutex_lock(&rdev->mtx);
        } else
                rdev = ERR_PTR(-ENODEV);
        dev_put(dev);
 out:
        mutex_unlock(&cfg80211_mutex);
        return rdev;
}

/* requires cfg80211_mutex to be held */
int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
                        char *newname)
{
        struct cfg80211_registered_device *rdev2;
        int wiphy_idx, taken = -1, result, digits;

        assert_cfg80211_lock();

        /* prohibit calling the thing phy%d when %d is not its number */
        sscanf(newname, PHY_NAME "%d%n", &wiphy_idx, &taken);
        if (taken == strlen(newname) && wiphy_idx != rdev->wiphy_idx) {
                /* count number of places needed to print wiphy_idx */
                digits = 1;
                while (wiphy_idx /= 10)
                        digits++;
                /*
                 * deny the name if it is phy<idx> where <idx> is printed
                 * without leading zeroes. taken == strlen(newname) here
                 */
                if (taken == strlen(PHY_NAME) + digits)
                        return -EINVAL;
        }


        /* Ignore nop renames */
        if (strcmp(newname, dev_name(&rdev->wiphy.dev)) == 0)
                return 0;

        /* Ensure another device does not already have this name. */
        list_for_each_entry(rdev2, &cfg80211_rdev_list, list)
                if (strcmp(newname, dev_name(&rdev2->wiphy.dev)) == 0)
                        return -EINVAL;

        result = device_rename(&rdev->wiphy.dev, newname);
        if (result)
                return result;

        if (rdev->wiphy.debugfsdir &&
            !debugfs_rename(rdev->wiphy.debugfsdir->d_parent,
                            rdev->wiphy.debugfsdir,
                            rdev->wiphy.debugfsdir->d_parent,
                            newname))
                pr_err("failed to rename debugfs dir to %s!\n", newname);

        nl80211_notify_dev_rename(rdev);

        return 0;
}

int cfg80211_switch_netns(struct cfg80211_registered_device *rdev,
                          struct net *net)
{
        struct wireless_dev *wdev;
        int err = 0;

        if (!(rdev->wiphy.flags & WIPHY_FLAG_NETNS_OK))
                return -EOPNOTSUPP;

        list_for_each_entry(wdev, &rdev->wdev_list, list) {
                if (!wdev->netdev)
                        continue;
                wdev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
                err = dev_change_net_namespace(wdev->netdev, net, "wlan%d");
                if (err)
                        break;
                wdev->netdev->features |= NETIF_F_NETNS_LOCAL;
        }

        if (err) {
                /* failed -- clean up to old netns */
                net = wiphy_net(&rdev->wiphy);

                list_for_each_entry_continue_reverse(wdev, &rdev->wdev_list,
                                                     list) {
                        if (!wdev->netdev)
                                continue;
                        wdev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
                        err = dev_change_net_namespace(wdev->netdev, net,
                                                        "wlan%d");
                        WARN_ON(err);
                        wdev->netdev->features |= NETIF_F_NETNS_LOCAL;
                }

                return err;
        }

        wiphy_net_set(&rdev->wiphy, net);

        err = device_rename(&rdev->wiphy.dev, dev_name(&rdev->wiphy.dev));
        WARN_ON(err);

        return 0;
}

static void cfg80211_rfkill_poll(struct rfkill *rfkill, void *data)
{
        struct cfg80211_registered_device *rdev = data;

        rdev->ops->rfkill_poll(&rdev->wiphy);
}

static int cfg80211_rfkill_set_block(void *data, bool blocked)
{
        struct cfg80211_registered_device *rdev = data;
        struct wireless_dev *wdev;

        if (!blocked)
                return 0;

        rtnl_lock();
        mutex_lock(&rdev->devlist_mtx);

        list_for_each_entry(wdev, &rdev->wdev_list, list)
                if (wdev->netdev)
                        dev_close(wdev->netdev);

        mutex_unlock(&rdev->devlist_mtx);
        rtnl_unlock();

        return 0;
}

static void cfg80211_rfkill_sync_work(struct work_struct *work)
{
        struct cfg80211_registered_device *rdev;

        rdev = container_of(work, struct cfg80211_registered_device, rfkill_sync);
        cfg80211_rfkill_set_block(rdev, rfkill_blocked(rdev->rfkill));
}

static void cfg80211_event_work(struct work_struct *work)
{
        struct cfg80211_registered_device *rdev;

        rdev = container_of(work, struct cfg80211_registered_device,
                            event_work);

        rtnl_lock();
        cfg80211_lock_rdev(rdev);

        cfg80211_process_rdev_events(rdev);
        cfg80211_unlock_rdev(rdev);
        rtnl_unlock();
}

/* exported functions */

struct wiphy *wiphy_new(const struct cfg80211_ops *ops, int sizeof_priv)
{
        static int wiphy_counter;

        struct cfg80211_registered_device *rdev;
        int alloc_size;

        WARN_ON(ops->add_key && (!ops->del_key || !ops->set_default_key));
        WARN_ON(ops->auth && (!ops->assoc || !ops->deauth || !ops->disassoc));
        WARN_ON(ops->connect && !ops->disconnect);
        WARN_ON(ops->join_ibss && !ops->leave_ibss);
        WARN_ON(ops->add_virtual_intf && !ops->del_virtual_intf);
        WARN_ON(ops->add_station && !ops->del_station);
        WARN_ON(ops->add_mpath && !ops->del_mpath);
        WARN_ON(ops->join_mesh && !ops->leave_mesh);

        alloc_size = sizeof(*rdev) + sizeof_priv;

        rdev = kzalloc(alloc_size, GFP_KERNEL);
        if (!rdev)
                return NULL;

        rdev->ops = ops;

        mutex_lock(&cfg80211_mutex);

        rdev->wiphy_idx = wiphy_counter++;

        if (unlikely(!wiphy_idx_valid(rdev->wiphy_idx))) {
                wiphy_counter--;
                mutex_unlock(&cfg80211_mutex);
                /* ugh, wrapped! */
                kfree(rdev);
                return NULL;
        }

        mutex_unlock(&cfg80211_mutex);

        /* give it a proper name */
        dev_set_name(&rdev->wiphy.dev, PHY_NAME "%d", rdev->wiphy_idx);

        mutex_init(&rdev->mtx);
        mutex_init(&rdev->devlist_mtx);
        mutex_init(&rdev->sched_scan_mtx);
        INIT_LIST_HEAD(&rdev->wdev_list);
        spin_lock_init(&rdev->bss_lock);
        INIT_LIST_HEAD(&rdev->bss_list);
        INIT_WORK(&rdev->scan_done_wk, __cfg80211_scan_done);
        INIT_WORK(&rdev->sched_scan_results_wk, __cfg80211_sched_scan_results);
#ifdef CONFIG_CFG80211_WEXT
        rdev->wiphy.wext = &cfg80211_wext_handler;
#endif

        device_initialize(&rdev->wiphy.dev);
        rdev->wiphy.dev.class = &ieee80211_class;
        rdev->wiphy.dev.platform_data = rdev;

#ifdef CONFIG_CFG80211_DEFAULT_PS
        rdev->wiphy.flags |= WIPHY_FLAG_PS_ON_BY_DEFAULT;
#endif

        wiphy_net_set(&rdev->wiphy, &init_net);

        rdev->rfkill_ops.set_block = cfg80211_rfkill_set_block;
        rdev->rfkill = rfkill_alloc(dev_name(&rdev->wiphy.dev),
                                   &rdev->wiphy.dev, RFKILL_TYPE_WLAN,
                                   &rdev->rfkill_ops, rdev);

        if (!rdev->rfkill) {
                kfree(rdev);
                return NULL;
        }

        INIT_WORK(&rdev->rfkill_sync, cfg80211_rfkill_sync_work);
        INIT_WORK(&rdev->conn_work, cfg80211_conn_work);
        INIT_WORK(&rdev->event_work, cfg80211_event_work);

        init_waitqueue_head(&rdev->dev_wait);

        /*
         * Initialize wiphy parameters to IEEE 802.11 MIB default values.
         * Fragmentation and RTS threshold are disabled by default with the
         * special -1 value.
         */
        rdev->wiphy.retry_short = 7;
        rdev->wiphy.retry_long = 4;
        rdev->wiphy.frag_threshold = (u32) -1;
        rdev->wiphy.rts_threshold = (u32) -1;
        rdev->wiphy.coverage_class = 0;

        return &rdev->wiphy;
}
EXPORT_SYMBOL(wiphy_new);

static int wiphy_verify_combinations(struct wiphy *wiphy)
{
        const struct ieee80211_iface_combination *c;
        int i, j;

        for (i = 0; i < wiphy->n_iface_combinations; i++) {
                u32 cnt = 0;
                u16 all_iftypes = 0;

                c = &wiphy->iface_combinations[i];

                /* Combinations with just one interface aren't real */
                if (WARN_ON(c->max_interfaces < 2))
                        return -EINVAL;

                /* Need at least one channel */
                if (WARN_ON(!c->num_different_channels))
                        return -EINVAL;

                /*
                 * Put a sane limit on maximum number of different
                 * channels to simplify channel accounting code.
                 */
                if (WARN_ON(c->num_different_channels >
                                CFG80211_MAX_NUM_DIFFERENT_CHANNELS))
                        return -EINVAL;

                if (WARN_ON(!c->n_limits))
                        return -EINVAL;

                for (j = 0; j < c->n_limits; j++) {
                        u16 types = c->limits[j].types;

                        /*
                         * interface types shouldn't overlap, this is
                         * used in cfg80211_can_change_interface()
                         */
                        if (WARN_ON(types & all_iftypes))
                                return -EINVAL;
                        all_iftypes |= types;

                        if (WARN_ON(!c->limits[j].max))
                                return -EINVAL;

                        /* Shouldn't list software iftypes in combinations! */
                        if (WARN_ON(wiphy->software_iftypes & types))
                                return -EINVAL;

                        cnt += c->limits[j].max;
                        /*
                         * Don't advertise an unsupported type
                         * in a combination.
                         */
                        if (WARN_ON((wiphy->interface_modes & types) != types))
                                return -EINVAL;
                }

                /* You can't even choose that many! */
                if (WARN_ON(cnt < c->max_interfaces))
                        return -EINVAL;
        }

        return 0;
}

int wiphy_register(struct wiphy *wiphy)
{
        struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
        int res;
        enum ieee80211_band band;
        struct ieee80211_supported_band *sband;
        bool have_band = false;
        int i;
        u16 ifmodes = wiphy->interface_modes;

#ifdef CONFIG_PM
        if (WARN_ON((wiphy->wowlan.flags & WIPHY_WOWLAN_GTK_REKEY_FAILURE) &&
                    !(wiphy->wowlan.flags & WIPHY_WOWLAN_SUPPORTS_GTK_REKEY)))
                return -EINVAL;
#endif

        if (WARN_ON(wiphy->ap_sme_capa &&
                    !(wiphy->flags & WIPHY_FLAG_HAVE_AP_SME)))
                return -EINVAL;

        if (WARN_ON(wiphy->addresses && !wiphy->n_addresses))
                return -EINVAL;

        if (WARN_ON(wiphy->addresses &&
                    !is_zero_ether_addr(wiphy->perm_addr) &&
                    memcmp(wiphy->perm_addr, wiphy->addresses[0].addr,
                           ETH_ALEN)))
                return -EINVAL;

        if (wiphy->addresses)
                memcpy(wiphy->perm_addr, wiphy->addresses[0].addr, ETH_ALEN);

        /* sanity check ifmodes */
        WARN_ON(!ifmodes);
        ifmodes &= ((1 << NUM_NL80211_IFTYPES) - 1) & ~1;
        if (WARN_ON(ifmodes != wiphy->interface_modes))
                wiphy->interface_modes = ifmodes;

        res = wiphy_verify_combinations(wiphy);
        if (res)
                return res;

        /* sanity check supported bands/channels */
        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                sband = wiphy->bands[band];
                if (!sband)
                        continue;

                sband->band = band;
                if (WARN_ON(!sband->n_channels))
                        return -EINVAL;
                /*
                 * on 60gHz band, there are no legacy rates, so
                 * n_bitrates is 0
                 */
                if (WARN_ON(band != IEEE80211_BAND_60GHZ &&
                            !sband->n_bitrates))
                        return -EINVAL;

                /*
                 * Since cfg80211_disable_40mhz_24ghz is global, we can
                 * modify the sband's ht data even if the driver uses a
                 * global structure for that.
                 */
                if (cfg80211_disable_40mhz_24ghz &&
                    band == IEEE80211_BAND_2GHZ &&
                    sband->ht_cap.ht_supported) {
                        sband->ht_cap.cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
                        sband->ht_cap.cap &= ~IEEE80211_HT_CAP_SGI_40;
                }

                /*
                 * Since we use a u32 for rate bitmaps in
                 * ieee80211_get_response_rate, we cannot
                 * have more than 32 legacy rates.
                 */
                if (WARN_ON(sband->n_bitrates > 32))
                        return -EINVAL;

                for (i = 0; i < sband->n_channels; i++) {
                        sband->channels[i].orig_flags =
                                sband->channels[i].flags;
                        sband->channels[i].orig_mag = INT_MAX;
                        sband->channels[i].orig_mpwr =
                                sband->channels[i].max_power;
                        sband->channels[i].band = band;
                }

                have_band = true;
        }

        if (!have_band) {
                WARN_ON(1);
                return -EINVAL;
        }

#ifdef CONFIG_PM
        if (rdev->wiphy.wowlan.n_patterns) {
                if (WARN_ON(!rdev->wiphy.wowlan.pattern_min_len ||
                            rdev->wiphy.wowlan.pattern_min_len >
                            rdev->wiphy.wowlan.pattern_max_len))
                        return -EINVAL;
        }
#endif

        /* check and set up bitrates */
        ieee80211_set_bitrate_flags(wiphy);

        mutex_lock(&cfg80211_mutex);

        res = device_add(&rdev->wiphy.dev);
        if (res) {
                mutex_unlock(&cfg80211_mutex);
                return res;
        }

        /* set up regulatory info */
        wiphy_regulatory_register(wiphy);

        list_add_rcu(&rdev->list, &cfg80211_rdev_list);
        cfg80211_rdev_list_generation++;

        /* add to debugfs */
        rdev->wiphy.debugfsdir =
                debugfs_create_dir(wiphy_name(&rdev->wiphy),
                                   ieee80211_debugfs_dir);
        if (IS_ERR(rdev->wiphy.debugfsdir))
                rdev->wiphy.debugfsdir = NULL;

        if (wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY) {
                struct regulatory_request request;

                request.wiphy_idx = get_wiphy_idx(wiphy);
                request.initiator = NL80211_REGDOM_SET_BY_DRIVER;
                request.alpha2[0] = '9';
                request.alpha2[1] = '9';

                nl80211_send_reg_change_event(&request);
        }

        cfg80211_debugfs_rdev_add(rdev);
        mutex_unlock(&cfg80211_mutex);

        /*
         * due to a locking dependency this has to be outside of the
         * cfg80211_mutex lock
         */
        res = rfkill_register(rdev->rfkill);
        if (res)
                goto out_rm_dev;

        rtnl_lock();
        rdev->wiphy.registered = true;
        rtnl_unlock();
        return 0;

out_rm_dev:
        device_del(&rdev->wiphy.dev);
        return res;
}
EXPORT_SYMBOL(wiphy_register);

void wiphy_rfkill_start_polling(struct wiphy *wiphy)
{
        struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);

        if (!rdev->ops->rfkill_poll)
                return;
        rdev->rfkill_ops.poll = cfg80211_rfkill_poll;
        rfkill_resume_polling(rdev->rfkill);
}
EXPORT_SYMBOL(wiphy_rfkill_start_polling);

void wiphy_rfkill_stop_polling(struct wiphy *wiphy)
{
        struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);

        rfkill_pause_polling(rdev->rfkill);
}
EXPORT_SYMBOL(wiphy_rfkill_stop_polling);

void wiphy_unregister(struct wiphy *wiphy)
{
        struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);

        rtnl_lock();
        rdev->wiphy.registered = false;
        rtnl_unlock();

        rfkill_unregister(rdev->rfkill);

        /* protect the device list */
        mutex_lock(&cfg80211_mutex);

        wait_event(rdev->dev_wait, ({
                int __count;
                mutex_lock(&rdev->devlist_mtx);
                __count = rdev->opencount;
                mutex_unlock(&rdev->devlist_mtx);
                __count == 0; }));

        mutex_lock(&rdev->devlist_mtx);
        BUG_ON(!list_empty(&rdev->wdev_list));
        mutex_unlock(&rdev->devlist_mtx);

        /*
         * First remove the hardware from everywhere, this makes
         * it impossible to find from userspace.
         */
        debugfs_remove_recursive(rdev->wiphy.debugfsdir);
        list_del_rcu(&rdev->list);
        synchronize_rcu();

        /*
         * Try to grab rdev->mtx. If a command is still in progress,
         * hopefully the driver will refuse it since it's tearing
         * down the device already. We wait for this command to complete
         * before unlinking the item from the list.
         * Note: as codified by the BUG_ON above we cannot get here if
         * a virtual interface is still present. Hence, we can only get
         * to lock contention here if userspace issues a command that
         * identified the hardware by wiphy index.
         */
        cfg80211_lock_rdev(rdev);
        /* nothing */
        cfg80211_unlock_rdev(rdev);

        /*
         * If this device got a regulatory hint tell core its
         * free to listen now to a new shiny device regulatory hint
         */
        wiphy_regulatory_deregister(wiphy);

        cfg80211_rdev_list_generation++;
        device_del(&rdev->wiphy.dev);

        mutex_unlock(&cfg80211_mutex);

        flush_work(&rdev->scan_done_wk);
        cancel_work_sync(&rdev->conn_work);
        flush_work(&rdev->event_work);

        if (rdev->wowlan && rdev->ops->set_wakeup)
                rdev->ops->set_wakeup(&rdev->wiphy, false);
        cfg80211_rdev_free_wowlan(rdev);
}
EXPORT_SYMBOL(wiphy_unregister);

void cfg80211_dev_free(struct cfg80211_registered_device *rdev)
{
        struct cfg80211_internal_bss *scan, *tmp;
        rfkill_destroy(rdev->rfkill);
        mutex_destroy(&rdev->mtx);
        mutex_destroy(&rdev->devlist_mtx);
        mutex_destroy(&rdev->sched_scan_mtx);
        list_for_each_entry_safe(scan, tmp, &rdev->bss_list, list)
                cfg80211_put_bss(&scan->pub);
        kfree(rdev);
}

void wiphy_free(struct wiphy *wiphy)
{
        put_device(&wiphy->dev);
}
EXPORT_SYMBOL(wiphy_free);

void wiphy_rfkill_set_hw_state(struct wiphy *wiphy, bool blocked)
{
        struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);

        if (rfkill_set_hw_state(rdev->rfkill, blocked))
                schedule_work(&rdev->rfkill_sync);
}
EXPORT_SYMBOL(wiphy_rfkill_set_hw_state);

static void wdev_cleanup_work(struct work_struct *work)
{
        struct wireless_dev *wdev;
        struct cfg80211_registered_device *rdev;

        wdev = container_of(work, struct wireless_dev, cleanup_work);
        rdev = wiphy_to_dev(wdev->wiphy);

        cfg80211_lock_rdev(rdev);

        if (WARN_ON(rdev->scan_req && rdev->scan_req->wdev == wdev)) {
                rdev->scan_req->aborted = true;
                ___cfg80211_scan_done(rdev, true);
        }

        cfg80211_unlock_rdev(rdev);

        mutex_lock(&rdev->sched_scan_mtx);

        if (WARN_ON(rdev->sched_scan_req &&
                    rdev->sched_scan_req->dev == wdev->netdev)) {
                __cfg80211_stop_sched_scan(rdev, false);
        }

        mutex_unlock(&rdev->sched_scan_mtx);

        mutex_lock(&rdev->devlist_mtx);
        rdev->opencount--;
        mutex_unlock(&rdev->devlist_mtx);
        wake_up(&rdev->dev_wait);

        dev_put(wdev->netdev);
}

static struct device_type wiphy_type = {
        .name   = "wlan",
};

void cfg80211_update_iface_num(struct cfg80211_registered_device *rdev,
                               enum nl80211_iftype iftype, int num)
{
        ASSERT_RTNL();

        rdev->num_running_ifaces += num;
        if (iftype == NL80211_IFTYPE_MONITOR)
                rdev->num_running_monitor_ifaces += num;
}

static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
                                         unsigned long state,
                                         void *ndev)
{
        struct net_device *dev = ndev;
        struct wireless_dev *wdev = dev->ieee80211_ptr;
        struct cfg80211_registered_device *rdev;
        int ret;

        if (!wdev)
                return NOTIFY_DONE;

        rdev = wiphy_to_dev(wdev->wiphy);

        WARN_ON(wdev->iftype == NL80211_IFTYPE_UNSPECIFIED);

        switch (state) {
        case NETDEV_POST_INIT:
                SET_NETDEV_DEVTYPE(dev, &wiphy_type);
                break;
        case NETDEV_REGISTER:
                /*
                 * NB: cannot take rdev->mtx here because this may be
                 * called within code protected by it when interfaces
                 * are added with nl80211.
                 */
                mutex_init(&wdev->mtx);
                INIT_WORK(&wdev->cleanup_work, wdev_cleanup_work);
                INIT_LIST_HEAD(&wdev->event_list);
                spin_lock_init(&wdev->event_lock);
                INIT_LIST_HEAD(&wdev->mgmt_registrations);
                spin_lock_init(&wdev->mgmt_registrations_lock);

                mutex_lock(&rdev->devlist_mtx);
                wdev->identifier = ++rdev->wdev_id;
                list_add_rcu(&wdev->list, &rdev->wdev_list);
                rdev->devlist_generation++;
                /* can only change netns with wiphy */
                dev->features |= NETIF_F_NETNS_LOCAL;

                if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
                                      "phy80211")) {
                        pr_err("failed to add phy80211 symlink to netdev!\n");
                }
                wdev->netdev = dev;
                wdev->sme_state = CFG80211_SME_IDLE;
                mutex_unlock(&rdev->devlist_mtx);
#ifdef CONFIG_CFG80211_WEXT
                wdev->wext.default_key = -1;
                wdev->wext.default_mgmt_key = -1;
                wdev->wext.connect.auth_type = NL80211_AUTHTYPE_AUTOMATIC;
#endif

                if (wdev->wiphy->flags & WIPHY_FLAG_PS_ON_BY_DEFAULT)
                        wdev->ps = true;
                else
                        wdev->ps = false;
                /* allow mac80211 to determine the timeout */
                wdev->ps_timeout = -1;

                if (!dev->ethtool_ops)
                        dev->ethtool_ops = &cfg80211_ethtool_ops;

                if ((wdev->iftype == NL80211_IFTYPE_STATION ||
                     wdev->iftype == NL80211_IFTYPE_P2P_CLIENT ||
                     wdev->iftype == NL80211_IFTYPE_ADHOC) && !wdev->use_4addr)
                        dev->priv_flags |= IFF_DONT_BRIDGE;
                break;
        case NETDEV_GOING_DOWN:
                switch (wdev->iftype) {
                case NL80211_IFTYPE_ADHOC:
                        cfg80211_leave_ibss(rdev, dev, true);
                        break;
                case NL80211_IFTYPE_P2P_CLIENT:
                case NL80211_IFTYPE_STATION:
                        mutex_lock(&rdev->sched_scan_mtx);
                        __cfg80211_stop_sched_scan(rdev, false);
                        mutex_unlock(&rdev->sched_scan_mtx);

                        wdev_lock(wdev);
#ifdef CONFIG_CFG80211_WEXT
                        kfree(wdev->wext.ie);
                        wdev->wext.ie = NULL;
                        wdev->wext.ie_len = 0;
                        wdev->wext.connect.auth_type = NL80211_AUTHTYPE_AUTOMATIC;
#endif
                        __cfg80211_disconnect(rdev, dev,
                                              WLAN_REASON_DEAUTH_LEAVING, true);
                        cfg80211_mlme_down(rdev, dev);
                        wdev_unlock(wdev);
                        break;
                case NL80211_IFTYPE_MESH_POINT:
                        cfg80211_leave_mesh(rdev, dev);
                        break;
                case NL80211_IFTYPE_AP:
                        cfg80211_stop_ap(rdev, dev);
                        break;
                default:
                        break;
                }
                wdev->beacon_interval = 0;
                break;
        case NETDEV_DOWN:
                cfg80211_update_iface_num(rdev, wdev->iftype, -1);
                dev_hold(dev);
                queue_work(cfg80211_wq, &wdev->cleanup_work);
                break;
        case NETDEV_UP:
                /*
                 * If we have a really quick DOWN/UP succession we may
                 * have this work still pending ... cancel it and see
                 * if it was pending, in which case we need to account
                 * for some of the work it would have done.
                 */
                if (cancel_work_sync(&wdev->cleanup_work)) {
                        mutex_lock(&rdev->devlist_mtx);
                        rdev->opencount--;
                        mutex_unlock(&rdev->devlist_mtx);
                        dev_put(dev);
                }
                cfg80211_update_iface_num(rdev, wdev->iftype, 1);
                cfg80211_lock_rdev(rdev);
                mutex_lock(&rdev->devlist_mtx);
                wdev_lock(wdev);
                switch (wdev->iftype) {
#ifdef CONFIG_CFG80211_WEXT
                case NL80211_IFTYPE_ADHOC:
                        cfg80211_ibss_wext_join(rdev, wdev);
                        break;
                case NL80211_IFTYPE_STATION:
                        cfg80211_mgd_wext_connect(rdev, wdev);
                        break;
#endif
#ifdef CONFIG_MAC80211_MESH
                case NL80211_IFTYPE_MESH_POINT:
                        {
                                /* backward compat code... */
                                struct mesh_setup setup;
                                memcpy(&setup, &default_mesh_setup,
                                                sizeof(setup));
                                 /* back compat only needed for mesh_id */
                                setup.mesh_id = wdev->ssid;
                                setup.mesh_id_len = wdev->mesh_id_up_len;
                                if (wdev->mesh_id_up_len)
                                        __cfg80211_join_mesh(rdev, dev,
                                                        &setup,
                                                        &default_mesh_config);
                                break;
                        }
#endif
                default:
                        break;
                }
                wdev_unlock(wdev);
                rdev->opencount++;
                mutex_unlock(&rdev->devlist_mtx);
                cfg80211_unlock_rdev(rdev);

                /*
                 * Configure power management to the driver here so that its
                 * correctly set also after interface type changes etc.
                 */
                if ((wdev->iftype == NL80211_IFTYPE_STATION ||
                     wdev->iftype == NL80211_IFTYPE_P2P_CLIENT) &&
                    rdev->ops->set_power_mgmt)
                        if (rdev->ops->set_power_mgmt(wdev->wiphy, dev,
                                                      wdev->ps,
                                                      wdev->ps_timeout)) {
                                /* assume this means it's off */
                                wdev->ps = false;
                        }
                break;
        case NETDEV_UNREGISTER:
                /*
                 * NB: cannot take rdev->mtx here because this may be
                 * called within code protected by it when interfaces
                 * are removed with nl80211.
                 */
                mutex_lock(&rdev->devlist_mtx);
                /*
                 * It is possible to get NETDEV_UNREGISTER
                 * multiple times. To detect that, check
                 * that the interface is still on the list
                 * of registered interfaces, and only then
                 * remove and clean it up.
                 */
                if (!list_empty(&wdev->list)) {
                        sysfs_remove_link(&dev->dev.kobj, "phy80211");
                        list_del_rcu(&wdev->list);
                        rdev->devlist_generation++;
                        cfg80211_mlme_purge_registrations(wdev);
#ifdef CONFIG_CFG80211_WEXT
                        kfree(wdev->wext.keys);
#endif
                }
                mutex_unlock(&rdev->devlist_mtx);
                /*
                 * synchronise (so that we won't find this netdev
                 * from other code any more) and then clear the list
                 * head so that the above code can safely check for
                 * !list_empty() to avoid double-cleanup.
                 */
                synchronize_rcu();
                INIT_LIST_HEAD(&wdev->list);
                /*
                 * Ensure that all events have been processed and
                 * freed.
                 */
                cfg80211_process_wdev_events(wdev);
                break;
        case NETDEV_PRE_UP:
                if (!(wdev->wiphy->interface_modes & BIT(wdev->iftype)))
                        return notifier_from_errno(-EOPNOTSUPP);
                if (rfkill_blocked(rdev->rfkill))
                        return notifier_from_errno(-ERFKILL);
                mutex_lock(&rdev->devlist_mtx);
                ret = cfg80211_can_add_interface(rdev, wdev->iftype);
                mutex_unlock(&rdev->devlist_mtx);
                if (ret)
                        return notifier_from_errno(ret);
                break;
        }

        return NOTIFY_DONE;
}

static struct notifier_block cfg80211_netdev_notifier = {
        .notifier_call = cfg80211_netdev_notifier_call,
};

static void __net_exit cfg80211_pernet_exit(struct net *net)
{
        struct cfg80211_registered_device *rdev;

        rtnl_lock();
        mutex_lock(&cfg80211_mutex);
        list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
                if (net_eq(wiphy_net(&rdev->wiphy), net))
                        WARN_ON(cfg80211_switch_netns(rdev, &init_net));
        }
        mutex_unlock(&cfg80211_mutex);
        rtnl_unlock();
}

static struct pernet_operations cfg80211_pernet_ops = {
        .exit = cfg80211_pernet_exit,
};

static int __init cfg80211_init(void)
{
        int err;

        err = register_pernet_device(&cfg80211_pernet_ops);
        if (err)
                goto out_fail_pernet;

        err = wiphy_sysfs_init();
        if (err)
                goto out_fail_sysfs;

        err = register_netdevice_notifier(&cfg80211_netdev_notifier);
        if (err)
                goto out_fail_notifier;

        err = nl80211_init();
        if (err)
                goto out_fail_nl80211;

        ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);

        err = regulatory_init();
        if (err)
                goto out_fail_reg;

        cfg80211_wq = create_singlethread_workqueue("cfg80211");
        if (!cfg80211_wq)
                goto out_fail_wq;

        return 0;

out_fail_wq:
        regulatory_exit();
out_fail_reg:
        debugfs_remove(ieee80211_debugfs_dir);
out_fail_nl80211:
        unregister_netdevice_notifier(&cfg80211_netdev_notifier);
out_fail_notifier:
        wiphy_sysfs_exit();
out_fail_sysfs:
        unregister_pernet_device(&cfg80211_pernet_ops);
out_fail_pernet:
        return err;
}
subsys_initcall(cfg80211_init);

static void __exit cfg80211_exit(void)
{
        debugfs_remove(ieee80211_debugfs_dir);
        nl80211_exit();
        unregister_netdevice_notifier(&cfg80211_netdev_notifier);
        wiphy_sysfs_exit();
        regulatory_exit();
        unregister_pernet_device(&cfg80211_pernet_ops);
        destroy_workqueue(cfg80211_wq);
}
module_exit(cfg80211_exit);