mac80211: Allow scanning on existing channel-type.

[mirror_ubuntu-artful-kernel.git] / net / mac80211 / main.c

/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
 *
 * 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 <net/mac80211.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <linux/rtnetlink.h>
#include <linux/bitmap.h>
#include <linux/pm_qos_params.h>
#include <linux/inetdevice.h>
#include <net/net_namespace.h>
#include <net/cfg80211.h>

#include "ieee80211_i.h"
#include "driver-ops.h"
#include "rate.h"
#include "mesh.h"
#include "wep.h"
#include "led.h"
#include "cfg.h"
#include "debugfs.h"


bool ieee80211_disable_40mhz_24ghz;
module_param(ieee80211_disable_40mhz_24ghz, bool, 0644);
MODULE_PARM_DESC(ieee80211_disable_40mhz_24ghz,
                 "Disable 40MHz support in the 2.4GHz band");

static struct lock_class_key ieee80211_rx_skb_queue_class;

void ieee80211_configure_filter(struct ieee80211_local *local)
{
        u64 mc;
        unsigned int changed_flags;
        unsigned int new_flags = 0;

        if (atomic_read(&local->iff_promiscs))
                new_flags |= FIF_PROMISC_IN_BSS;

        if (atomic_read(&local->iff_allmultis))
                new_flags |= FIF_ALLMULTI;

        if (local->monitors || local->scanning)
                new_flags |= FIF_BCN_PRBRESP_PROMISC;

        if (local->fif_probe_req || local->probe_req_reg)
                new_flags |= FIF_PROBE_REQ;

        if (local->fif_fcsfail)
                new_flags |= FIF_FCSFAIL;

        if (local->fif_plcpfail)
                new_flags |= FIF_PLCPFAIL;

        if (local->fif_control)
                new_flags |= FIF_CONTROL;

        if (local->fif_other_bss)
                new_flags |= FIF_OTHER_BSS;

        if (local->fif_pspoll)
                new_flags |= FIF_PSPOLL;

        spin_lock_bh(&local->filter_lock);
        changed_flags = local->filter_flags ^ new_flags;

        mc = drv_prepare_multicast(local, &local->mc_list);
        spin_unlock_bh(&local->filter_lock);

        /* be a bit nasty */
        new_flags |= (1<<31);

        drv_configure_filter(local, changed_flags, &new_flags, mc);

        WARN_ON(new_flags & (1<<31));

        local->filter_flags = new_flags & ~(1<<31);
}

static void ieee80211_reconfig_filter(struct work_struct *work)
{
        struct ieee80211_local *local =
                container_of(work, struct ieee80211_local, reconfig_filter);

        ieee80211_configure_filter(local);
}

/*
 * Returns true if we are logically configured to be on
 * the operating channel AND the hardware-conf is currently
 * configured on the operating channel.  Compares channel-type
 * as well.
 */
bool ieee80211_cfg_on_oper_channel(struct ieee80211_local *local)
{
        struct ieee80211_channel *chan, *scan_chan;
        enum nl80211_channel_type channel_type;

        /* This logic needs to match logic in ieee80211_hw_config */
        if (local->scan_channel) {
                chan = local->scan_channel;
                /* If scanning on oper channel, use whatever channel-type
                 * is currently in use.
                 */
                if (chan == local->oper_channel)
                        channel_type = local->_oper_channel_type;
                else
                        channel_type = NL80211_CHAN_NO_HT;
        } else if (local->tmp_channel) {
                chan = scan_chan = local->tmp_channel;
                channel_type = local->tmp_channel_type;
        } else {
                chan = local->oper_channel;
                channel_type = local->_oper_channel_type;
        }

        if (chan != local->oper_channel ||
            channel_type != local->_oper_channel_type)
                return false;

        /* Check current hardware-config against oper_channel. */
        if ((local->oper_channel != local->hw.conf.channel) ||
            (local->_oper_channel_type != local->hw.conf.channel_type))
                return false;

        return true;
}

int ieee80211_hw_config(struct ieee80211_local *local, u32 changed)
{
        struct ieee80211_channel *chan, *scan_chan;
        int ret = 0;
        int power;
        enum nl80211_channel_type channel_type;
        u32 offchannel_flag;

        might_sleep();

        scan_chan = local->scan_channel;

        /* If this off-channel logic ever changes,  ieee80211_on_oper_channel
         * may need to change as well.
         */
        offchannel_flag = local->hw.conf.flags & IEEE80211_CONF_OFFCHANNEL;
        if (scan_chan) {
                chan = scan_chan;
                /* If scanning on oper channel, use whatever channel-type
                 * is currently in use.
                 */
                if (chan == local->oper_channel)
                        channel_type = local->_oper_channel_type;
                else
                        channel_type = NL80211_CHAN_NO_HT;
        } else if (local->tmp_channel) {
                chan = scan_chan = local->tmp_channel;
                channel_type = local->tmp_channel_type;
        } else {
                chan = local->oper_channel;
                channel_type = local->_oper_channel_type;
        }

        if (chan != local->oper_channel ||
            channel_type != local->_oper_channel_type)
                local->hw.conf.flags |= IEEE80211_CONF_OFFCHANNEL;
        else
                local->hw.conf.flags &= ~IEEE80211_CONF_OFFCHANNEL;

        offchannel_flag ^= local->hw.conf.flags & IEEE80211_CONF_OFFCHANNEL;

        if (offchannel_flag || chan != local->hw.conf.channel ||
            channel_type != local->hw.conf.channel_type) {
                local->hw.conf.channel = chan;
                local->hw.conf.channel_type = channel_type;
                changed |= IEEE80211_CONF_CHANGE_CHANNEL;
        }

        if (!conf_is_ht(&local->hw.conf)) {
                /*
                 * mac80211.h documents that this is only valid
                 * when the channel is set to an HT type, and
                 * that otherwise STATIC is used.
                 */
                local->hw.conf.smps_mode = IEEE80211_SMPS_STATIC;
        } else if (local->hw.conf.smps_mode != local->smps_mode) {
                local->hw.conf.smps_mode = local->smps_mode;
                changed |= IEEE80211_CONF_CHANGE_SMPS;
        }

        if (scan_chan)
                power = chan->max_power;
        else
                power = local->power_constr_level ?
                        (chan->max_power - local->power_constr_level) :
                        chan->max_power;

        if (local->user_power_level >= 0)
                power = min(power, local->user_power_level);

        if (local->hw.conf.power_level != power) {
                changed |= IEEE80211_CONF_CHANGE_POWER;
                local->hw.conf.power_level = power;
        }

        if (changed && local->open_count) {
                ret = drv_config(local, changed);
                /*
                 * Goal:
                 * HW reconfiguration should never fail, the driver has told
                 * us what it can support so it should live up to that promise.
                 *
                 * Current status:
                 * rfkill is not integrated with mac80211 and a
                 * configuration command can thus fail if hardware rfkill
                 * is enabled
                 *
                 * FIXME: integrate rfkill with mac80211 and then add this
                 * WARN_ON() back
                 *
                 */
                /* WARN_ON(ret); */
        }

        return ret;
}

void ieee80211_bss_info_change_notify(struct ieee80211_sub_if_data *sdata,
                                      u32 changed)
{
        struct ieee80211_local *local = sdata->local;
        static const u8 zero[ETH_ALEN] = { 0 };

        if (!changed)
                return;

        if (sdata->vif.type == NL80211_IFTYPE_STATION) {
                /*
                 * While not associated, claim a BSSID of all-zeroes
                 * so that drivers don't do any weird things with the
                 * BSSID at that time.
                 */
                if (sdata->vif.bss_conf.assoc)
                        sdata->vif.bss_conf.bssid = sdata->u.mgd.bssid;
                else
                        sdata->vif.bss_conf.bssid = zero;
        } else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
                sdata->vif.bss_conf.bssid = sdata->u.ibss.bssid;
        else if (sdata->vif.type == NL80211_IFTYPE_AP)
                sdata->vif.bss_conf.bssid = sdata->vif.addr;
        else if (sdata->vif.type == NL80211_IFTYPE_WDS)
                sdata->vif.bss_conf.bssid = NULL;
        else if (ieee80211_vif_is_mesh(&sdata->vif)) {
                sdata->vif.bss_conf.bssid = zero;
        } else {
                WARN_ON(1);
                return;
        }

        switch (sdata->vif.type) {
        case NL80211_IFTYPE_AP:
        case NL80211_IFTYPE_ADHOC:
        case NL80211_IFTYPE_WDS:
        case NL80211_IFTYPE_MESH_POINT:
                break;
        default:
                /* do not warn to simplify caller in scan.c */
                changed &= ~BSS_CHANGED_BEACON_ENABLED;
                if (WARN_ON(changed & BSS_CHANGED_BEACON))
                        return;
                break;
        }

        if (changed & BSS_CHANGED_BEACON_ENABLED) {
                if (local->quiescing || !ieee80211_sdata_running(sdata) ||
                    test_bit(SDATA_STATE_OFFCHANNEL, &sdata->state)) {
                        sdata->vif.bss_conf.enable_beacon = false;
                } else {
                        /*
                         * Beacon should be enabled, but AP mode must
                         * check whether there is a beacon configured.
                         */
                        switch (sdata->vif.type) {
                        case NL80211_IFTYPE_AP:
                                sdata->vif.bss_conf.enable_beacon =
                                        !!sdata->u.ap.beacon;
                                break;
                        case NL80211_IFTYPE_ADHOC:
                                sdata->vif.bss_conf.enable_beacon =
                                        !!sdata->u.ibss.presp;
                                break;
#ifdef CONFIG_MAC80211_MESH
                        case NL80211_IFTYPE_MESH_POINT:
                                sdata->vif.bss_conf.enable_beacon =
                                        !!sdata->u.mesh.mesh_id_len;
                                break;
#endif
                        default:
                                /* not reached */
                                WARN_ON(1);
                                break;
                        }
                }
        }

        drv_bss_info_changed(local, sdata, &sdata->vif.bss_conf, changed);
}

u32 ieee80211_reset_erp_info(struct ieee80211_sub_if_data *sdata)
{
        sdata->vif.bss_conf.use_cts_prot = false;
        sdata->vif.bss_conf.use_short_preamble = false;
        sdata->vif.bss_conf.use_short_slot = false;
        return BSS_CHANGED_ERP_CTS_PROT |
               BSS_CHANGED_ERP_PREAMBLE |
               BSS_CHANGED_ERP_SLOT;
}

static void ieee80211_tasklet_handler(unsigned long data)
{
        struct ieee80211_local *local = (struct ieee80211_local *) data;
        struct sk_buff *skb;

        while ((skb = skb_dequeue(&local->skb_queue)) ||
               (skb = skb_dequeue(&local->skb_queue_unreliable))) {
                switch (skb->pkt_type) {
                case IEEE80211_RX_MSG:
                        /* Clear skb->pkt_type in order to not confuse kernel
                         * netstack. */
                        skb->pkt_type = 0;
                        ieee80211_rx(local_to_hw(local), skb);
                        break;
                case IEEE80211_TX_STATUS_MSG:
                        skb->pkt_type = 0;
                        ieee80211_tx_status(local_to_hw(local), skb);
                        break;
                default:
                        WARN(1, "mac80211: Packet is of unknown type %d\n",
                             skb->pkt_type);
                        dev_kfree_skb(skb);
                        break;
                }
        }
}

static void ieee80211_restart_work(struct work_struct *work)
{
        struct ieee80211_local *local =
                container_of(work, struct ieee80211_local, restart_work);

        /* wait for scan work complete */
        flush_workqueue(local->workqueue);

        mutex_lock(&local->mtx);
        WARN(test_bit(SCAN_HW_SCANNING, &local->scanning),
                "%s called with hardware scan in progress\n", __func__);
        mutex_unlock(&local->mtx);

        rtnl_lock();
        ieee80211_scan_cancel(local);
        ieee80211_reconfig(local);
        rtnl_unlock();
}

void ieee80211_restart_hw(struct ieee80211_hw *hw)
{
        struct ieee80211_local *local = hw_to_local(hw);

        trace_api_restart_hw(local);

        /* use this reason, ieee80211_reconfig will unblock it */
        ieee80211_stop_queues_by_reason(hw,
                IEEE80211_QUEUE_STOP_REASON_SUSPEND);

        schedule_work(&local->restart_work);
}
EXPORT_SYMBOL(ieee80211_restart_hw);

static void ieee80211_recalc_smps_work(struct work_struct *work)
{
        struct ieee80211_local *local =
                container_of(work, struct ieee80211_local, recalc_smps);

        mutex_lock(&local->iflist_mtx);
        ieee80211_recalc_smps(local);
        mutex_unlock(&local->iflist_mtx);
}

#ifdef CONFIG_INET
static int ieee80211_ifa_changed(struct notifier_block *nb,
                                 unsigned long data, void *arg)
{
        struct in_ifaddr *ifa = arg;
        struct ieee80211_local *local =
                container_of(nb, struct ieee80211_local,
                             ifa_notifier);
        struct net_device *ndev = ifa->ifa_dev->dev;
        struct wireless_dev *wdev = ndev->ieee80211_ptr;
        struct in_device *idev;
        struct ieee80211_sub_if_data *sdata;
        struct ieee80211_bss_conf *bss_conf;
        struct ieee80211_if_managed *ifmgd;
        int c = 0;

        /* Make sure it's our interface that got changed */
        if (!wdev)
                return NOTIFY_DONE;

        if (wdev->wiphy != local->hw.wiphy)
                return NOTIFY_DONE;

        sdata = IEEE80211_DEV_TO_SUB_IF(ndev);
        bss_conf = &sdata->vif.bss_conf;

        if (!ieee80211_sdata_running(sdata))
                return NOTIFY_DONE;

        /* ARP filtering is only supported in managed mode */
        if (sdata->vif.type != NL80211_IFTYPE_STATION)
                return NOTIFY_DONE;

        idev = __in_dev_get_rtnl(sdata->dev);
        if (!idev)
                return NOTIFY_DONE;

        ifmgd = &sdata->u.mgd;
        mutex_lock(&ifmgd->mtx);

        /* Copy the addresses to the bss_conf list */
        ifa = idev->ifa_list;
        while (c < IEEE80211_BSS_ARP_ADDR_LIST_LEN && ifa) {
                bss_conf->arp_addr_list[c] = ifa->ifa_address;
                ifa = ifa->ifa_next;
                c++;
        }

        /* If not all addresses fit the list, disable filtering */
        if (ifa) {
                sdata->arp_filter_state = false;
                c = 0;
        } else {
                sdata->arp_filter_state = true;
        }
        bss_conf->arp_addr_cnt = c;

        /* Configure driver only if associated */
        if (ifmgd->associated) {
                bss_conf->arp_filter_enabled = sdata->arp_filter_state;
                ieee80211_bss_info_change_notify(sdata,
                                                 BSS_CHANGED_ARP_FILTER);
        }

        mutex_unlock(&ifmgd->mtx);

        return NOTIFY_DONE;
}
#endif

static int ieee80211_napi_poll(struct napi_struct *napi, int budget)
{
        struct ieee80211_local *local =
                container_of(napi, struct ieee80211_local, napi);

        return local->ops->napi_poll(&local->hw, budget);
}

void ieee80211_napi_schedule(struct ieee80211_hw *hw)
{
        struct ieee80211_local *local = hw_to_local(hw);

        napi_schedule(&local->napi);
}
EXPORT_SYMBOL(ieee80211_napi_schedule);

void ieee80211_napi_complete(struct ieee80211_hw *hw)
{
        struct ieee80211_local *local = hw_to_local(hw);

        napi_complete(&local->napi);
}
EXPORT_SYMBOL(ieee80211_napi_complete);

/* There isn't a lot of sense in it, but you can transmit anything you like */
static const struct ieee80211_txrx_stypes
ieee80211_default_mgmt_stypes[NUM_NL80211_IFTYPES] = {
        [NL80211_IFTYPE_ADHOC] = {
                .tx = 0xffff,
                .rx = BIT(IEEE80211_STYPE_ACTION >> 4),
        },
        [NL80211_IFTYPE_STATION] = {
                .tx = 0xffff,
                .rx = BIT(IEEE80211_STYPE_ACTION >> 4) |
                        BIT(IEEE80211_STYPE_PROBE_REQ >> 4),
        },
        [NL80211_IFTYPE_AP] = {
                .tx = 0xffff,
                .rx = BIT(IEEE80211_STYPE_ASSOC_REQ >> 4) |
                        BIT(IEEE80211_STYPE_REASSOC_REQ >> 4) |
                        BIT(IEEE80211_STYPE_PROBE_REQ >> 4) |
                        BIT(IEEE80211_STYPE_DISASSOC >> 4) |
                        BIT(IEEE80211_STYPE_AUTH >> 4) |
                        BIT(IEEE80211_STYPE_DEAUTH >> 4) |
                        BIT(IEEE80211_STYPE_ACTION >> 4),
        },
        [NL80211_IFTYPE_AP_VLAN] = {
                /* copy AP */
                .tx = 0xffff,
                .rx = BIT(IEEE80211_STYPE_ASSOC_REQ >> 4) |
                        BIT(IEEE80211_STYPE_REASSOC_REQ >> 4) |
                        BIT(IEEE80211_STYPE_PROBE_REQ >> 4) |
                        BIT(IEEE80211_STYPE_DISASSOC >> 4) |
                        BIT(IEEE80211_STYPE_AUTH >> 4) |
                        BIT(IEEE80211_STYPE_DEAUTH >> 4) |
                        BIT(IEEE80211_STYPE_ACTION >> 4),
        },
        [NL80211_IFTYPE_P2P_CLIENT] = {
                .tx = 0xffff,
                .rx = BIT(IEEE80211_STYPE_ACTION >> 4) |
                        BIT(IEEE80211_STYPE_PROBE_REQ >> 4),
        },
        [NL80211_IFTYPE_P2P_GO] = {
                .tx = 0xffff,
                .rx = BIT(IEEE80211_STYPE_ASSOC_REQ >> 4) |
                        BIT(IEEE80211_STYPE_REASSOC_REQ >> 4) |
                        BIT(IEEE80211_STYPE_PROBE_REQ >> 4) |
                        BIT(IEEE80211_STYPE_DISASSOC >> 4) |
                        BIT(IEEE80211_STYPE_AUTH >> 4) |
                        BIT(IEEE80211_STYPE_DEAUTH >> 4) |
                        BIT(IEEE80211_STYPE_ACTION >> 4),
        },
        [NL80211_IFTYPE_MESH_POINT] = {
                .tx = 0xffff,
                .rx = BIT(IEEE80211_STYPE_ACTION >> 4),
        },
};

struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
                                        const struct ieee80211_ops *ops)
{
        struct ieee80211_local *local;
        int priv_size, i;
        struct wiphy *wiphy;

        /* Ensure 32-byte alignment of our private data and hw private data.
         * We use the wiphy priv data for both our ieee80211_local and for
         * the driver's private data
         *
         * In memory it'll be like this:
         *
         * +-------------------------+
         * | struct wiphy           |
         * +-------------------------+
         * | struct ieee80211_local  |
         * +-------------------------+
         * | driver's private data   |
         * +-------------------------+
         *
         */
        priv_size = ALIGN(sizeof(*local), NETDEV_ALIGN) + priv_data_len;

        wiphy = wiphy_new(&mac80211_config_ops, priv_size);

        if (!wiphy)
                return NULL;

        wiphy->mgmt_stypes = ieee80211_default_mgmt_stypes;

        wiphy->privid = mac80211_wiphy_privid;

        wiphy->flags |= WIPHY_FLAG_NETNS_OK |
                        WIPHY_FLAG_4ADDR_AP |
                        WIPHY_FLAG_4ADDR_STATION |
                        WIPHY_FLAG_SUPPORTS_SEPARATE_DEFAULT_KEYS;

        if (!ops->set_key)
                wiphy->flags |= WIPHY_FLAG_IBSS_RSN;

        wiphy->bss_priv_size = sizeof(struct ieee80211_bss);

        local = wiphy_priv(wiphy);

        local->hw.wiphy = wiphy;

        local->hw.priv = (char *)local + ALIGN(sizeof(*local), NETDEV_ALIGN);

        BUG_ON(!ops->tx);
        BUG_ON(!ops->start);
        BUG_ON(!ops->stop);
        BUG_ON(!ops->config);
        BUG_ON(!ops->add_interface);
        BUG_ON(!ops->remove_interface);
        BUG_ON(!ops->configure_filter);
        local->ops = ops;

        /* set up some defaults */
        local->hw.queues = 1;
        local->hw.max_rates = 1;
        local->hw.max_report_rates = 0;
        local->hw.max_rx_aggregation_subframes = IEEE80211_MAX_AMPDU_BUF;
        local->hw.conf.long_frame_max_tx_count = wiphy->retry_long;
        local->hw.conf.short_frame_max_tx_count = wiphy->retry_short;
        local->user_power_level = -1;
        local->uapsd_queues = IEEE80211_DEFAULT_UAPSD_QUEUES;
        local->uapsd_max_sp_len = IEEE80211_DEFAULT_MAX_SP_LEN;

        INIT_LIST_HEAD(&local->interfaces);

        __hw_addr_init(&local->mc_list);

        mutex_init(&local->iflist_mtx);
        mutex_init(&local->mtx);

        mutex_init(&local->key_mtx);
        spin_lock_init(&local->filter_lock);
        spin_lock_init(&local->queue_stop_reason_lock);

        /*
         * The rx_skb_queue is only accessed from tasklets,
         * but other SKB queues are used from within IRQ
         * context. Therefore, this one needs a different
         * locking class so our direct, non-irq-safe use of
         * the queue's lock doesn't throw lockdep warnings.
         */
        skb_queue_head_init_class(&local->rx_skb_queue,
                                  &ieee80211_rx_skb_queue_class);

        INIT_DELAYED_WORK(&local->scan_work, ieee80211_scan_work);

        ieee80211_work_init(local);

        INIT_WORK(&local->restart_work, ieee80211_restart_work);

        INIT_WORK(&local->reconfig_filter, ieee80211_reconfig_filter);
        INIT_WORK(&local->recalc_smps, ieee80211_recalc_smps_work);
        local->smps_mode = IEEE80211_SMPS_OFF;

        INIT_WORK(&local->dynamic_ps_enable_work,
                  ieee80211_dynamic_ps_enable_work);
        INIT_WORK(&local->dynamic_ps_disable_work,
                  ieee80211_dynamic_ps_disable_work);
        setup_timer(&local->dynamic_ps_timer,
                    ieee80211_dynamic_ps_timer, (unsigned long) local);

        sta_info_init(local);

        for (i = 0; i < IEEE80211_MAX_QUEUES; i++) {
                skb_queue_head_init(&local->pending[i]);
                atomic_set(&local->agg_queue_stop[i], 0);
        }
        tasklet_init(&local->tx_pending_tasklet, ieee80211_tx_pending,
                     (unsigned long)local);

        tasklet_init(&local->tasklet,
                     ieee80211_tasklet_handler,
                     (unsigned long) local);

        skb_queue_head_init(&local->skb_queue);
        skb_queue_head_init(&local->skb_queue_unreliable);

        /* init dummy netdev for use w/ NAPI */
        init_dummy_netdev(&local->napi_dev);

        ieee80211_led_names(local);

        ieee80211_hw_roc_setup(local);

        return local_to_hw(local);
}
EXPORT_SYMBOL(ieee80211_alloc_hw);

int ieee80211_register_hw(struct ieee80211_hw *hw)
{
        struct ieee80211_local *local = hw_to_local(hw);
        int result;
        enum ieee80211_band band;
        int channels, max_bitrates;
        bool supp_ht;
        static const u32 cipher_suites[] = {
                /* keep WEP first, it may be removed below */
                WLAN_CIPHER_SUITE_WEP40,
                WLAN_CIPHER_SUITE_WEP104,
                WLAN_CIPHER_SUITE_TKIP,
                WLAN_CIPHER_SUITE_CCMP,

                /* keep last -- depends on hw flags! */
                WLAN_CIPHER_SUITE_AES_CMAC
        };

        if (hw->max_report_rates == 0)
                hw->max_report_rates = hw->max_rates;

        /*
         * generic code guarantees at least one band,
         * set this very early because much code assumes
         * that hw.conf.channel is assigned
         */
        channels = 0;
        max_bitrates = 0;
        supp_ht = false;
        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                struct ieee80211_supported_band *sband;

                sband = local->hw.wiphy->bands[band];
                if (!sband)
                        continue;
                if (!local->oper_channel) {
                        /* init channel we're on */
                        local->hw.conf.channel =
                        local->oper_channel = &sband->channels[0];
                        local->hw.conf.channel_type = NL80211_CHAN_NO_HT;
                }
                channels += sband->n_channels;

                if (max_bitrates < sband->n_bitrates)
                        max_bitrates = sband->n_bitrates;
                supp_ht = supp_ht || sband->ht_cap.ht_supported;
        }

        local->int_scan_req = kzalloc(sizeof(*local->int_scan_req) +
                                      sizeof(void *) * channels, GFP_KERNEL);
        if (!local->int_scan_req)
                return -ENOMEM;

        /* if low-level driver supports AP, we also support VLAN */
        if (local->hw.wiphy->interface_modes & BIT(NL80211_IFTYPE_AP))
                local->hw.wiphy->interface_modes |= BIT(NL80211_IFTYPE_AP_VLAN);

        /* mac80211 always supports monitor */
        local->hw.wiphy->interface_modes |= BIT(NL80211_IFTYPE_MONITOR);

#ifndef CONFIG_MAC80211_MESH
        /* mesh depends on Kconfig, but drivers should set it if they want */
        local->hw.wiphy->interface_modes &= ~BIT(NL80211_IFTYPE_MESH_POINT);
#endif

        /* mac80211 supports control port protocol changing */
        local->hw.wiphy->flags |= WIPHY_FLAG_CONTROL_PORT_PROTOCOL;

        if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
                local->hw.wiphy->signal_type = CFG80211_SIGNAL_TYPE_MBM;
        else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
                local->hw.wiphy->signal_type = CFG80211_SIGNAL_TYPE_UNSPEC;

        WARN((local->hw.flags & IEEE80211_HW_SUPPORTS_UAPSD)
             && (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK),
             "U-APSD not supported with HW_PS_NULLFUNC_STACK\n");

        /*
         * Calculate scan IE length -- we need this to alloc
         * memory and to subtract from the driver limit. It
         * includes the DS Params, (extended) supported rates, and HT
         * information -- SSID is the driver's responsibility.
         */
        local->scan_ies_len = 4 + max_bitrates /* (ext) supp rates */ +
                3 /* DS Params */;
        if (supp_ht)
                local->scan_ies_len += 2 + sizeof(struct ieee80211_ht_cap);

        if (!local->ops->hw_scan) {
                /* For hw_scan, driver needs to set these up. */
                local->hw.wiphy->max_scan_ssids = 4;
                local->hw.wiphy->max_scan_ie_len = IEEE80211_MAX_DATA_LEN;
        }

        /*
         * If the driver supports any scan IEs, then assume the
         * limit includes the IEs mac80211 will add, otherwise
         * leave it at zero and let the driver sort it out; we
         * still pass our IEs to the driver but userspace will
         * not be allowed to in that case.
         */
        if (local->hw.wiphy->max_scan_ie_len)
                local->hw.wiphy->max_scan_ie_len -= local->scan_ies_len;

        /* Set up cipher suites unless driver already did */
        if (!local->hw.wiphy->cipher_suites) {
                local->hw.wiphy->cipher_suites = cipher_suites;
                local->hw.wiphy->n_cipher_suites = ARRAY_SIZE(cipher_suites);
                if (!(local->hw.flags & IEEE80211_HW_MFP_CAPABLE))
                        local->hw.wiphy->n_cipher_suites--;
        }
        if (IS_ERR(local->wep_tx_tfm) || IS_ERR(local->wep_rx_tfm)) {
                if (local->hw.wiphy->cipher_suites == cipher_suites) {
                        local->hw.wiphy->cipher_suites += 2;
                        local->hw.wiphy->n_cipher_suites -= 2;
                } else {
                        u32 *suites;
                        int r, w = 0;

                        /* Filter out WEP */

                        suites = kmemdup(
                                local->hw.wiphy->cipher_suites,
                                sizeof(u32) * local->hw.wiphy->n_cipher_suites,
                                GFP_KERNEL);
                        if (!suites)
                                return -ENOMEM;
                        for (r = 0; r < local->hw.wiphy->n_cipher_suites; r++) {
                                u32 suite = local->hw.wiphy->cipher_suites[r];
                                if (suite == WLAN_CIPHER_SUITE_WEP40 ||
                                    suite == WLAN_CIPHER_SUITE_WEP104)
                                        continue;
                                suites[w++] = suite;
                        }
                        local->hw.wiphy->cipher_suites = suites;
                        local->hw.wiphy->n_cipher_suites = w;
                        local->wiphy_ciphers_allocated = true;
                }
        }

        if (!local->ops->remain_on_channel)
                local->hw.wiphy->max_remain_on_channel_duration = 5000;

        result = wiphy_register(local->hw.wiphy);
        if (result < 0)
                goto fail_wiphy_register;

        /*
         * We use the number of queues for feature tests (QoS, HT) internally
         * so restrict them appropriately.
         */
        if (hw->queues > IEEE80211_MAX_QUEUES)
                hw->queues = IEEE80211_MAX_QUEUES;

        local->workqueue =
                alloc_ordered_workqueue(wiphy_name(local->hw.wiphy), 0);
        if (!local->workqueue) {
                result = -ENOMEM;
                goto fail_workqueue;
        }

        /*
         * The hardware needs headroom for sending the frame,
         * and we need some headroom for passing the frame to monitor
         * interfaces, but never both at the same time.
         */
        BUILD_BUG_ON(IEEE80211_TX_STATUS_HEADROOM !=
                        sizeof(struct ieee80211_tx_status_rtap_hdr));
        local->tx_headroom = max_t(unsigned int , local->hw.extra_tx_headroom,
                                   sizeof(struct ieee80211_tx_status_rtap_hdr));

        debugfs_hw_add(local);

        /*
         * if the driver doesn't specify a max listen interval we
         * use 5 which should be a safe default
         */
        if (local->hw.max_listen_interval == 0)
                local->hw.max_listen_interval = 5;

        local->hw.conf.listen_interval = local->hw.max_listen_interval;

        local->dynamic_ps_forced_timeout = -1;

        result = sta_info_start(local);
        if (result < 0)
                goto fail_sta_info;

        result = ieee80211_wep_init(local);
        if (result < 0)
                wiphy_debug(local->hw.wiphy, "Failed to initialize wep: %d\n",
                            result);

        rtnl_lock();

        result = ieee80211_init_rate_ctrl_alg(local,
                                              hw->rate_control_algorithm);
        if (result < 0) {
                wiphy_debug(local->hw.wiphy,
                            "Failed to initialize rate control algorithm\n");
                goto fail_rate;
        }

        /* add one default STA interface if supported */
        if (local->hw.wiphy->interface_modes & BIT(NL80211_IFTYPE_STATION)) {
                result = ieee80211_if_add(local, "wlan%d", NULL,
                                          NL80211_IFTYPE_STATION, NULL);
                if (result)
                        wiphy_warn(local->hw.wiphy,
                                   "Failed to add default virtual iface\n");
        }

        rtnl_unlock();

        ieee80211_led_init(local);

        local->network_latency_notifier.notifier_call =
                ieee80211_max_network_latency;
        result = pm_qos_add_notifier(PM_QOS_NETWORK_LATENCY,
                                     &local->network_latency_notifier);
        if (result) {
                rtnl_lock();
                goto fail_pm_qos;
        }

#ifdef CONFIG_INET
        local->ifa_notifier.notifier_call = ieee80211_ifa_changed;
        result = register_inetaddr_notifier(&local->ifa_notifier);
        if (result)
                goto fail_ifa;
#endif

        netif_napi_add(&local->napi_dev, &local->napi, ieee80211_napi_poll,
                        local->hw.napi_weight);

        return 0;

#ifdef CONFIG_INET
 fail_ifa:
        pm_qos_remove_notifier(PM_QOS_NETWORK_LATENCY,
                               &local->network_latency_notifier);
        rtnl_lock();
#endif
 fail_pm_qos:
        ieee80211_led_exit(local);
        ieee80211_remove_interfaces(local);
 fail_rate:
        rtnl_unlock();
        ieee80211_wep_free(local);
        sta_info_stop(local);
 fail_sta_info:
        destroy_workqueue(local->workqueue);
 fail_workqueue:
        wiphy_unregister(local->hw.wiphy);
 fail_wiphy_register:
        if (local->wiphy_ciphers_allocated)
                kfree(local->hw.wiphy->cipher_suites);
        kfree(local->int_scan_req);
        return result;
}
EXPORT_SYMBOL(ieee80211_register_hw);

void ieee80211_unregister_hw(struct ieee80211_hw *hw)
{
        struct ieee80211_local *local = hw_to_local(hw);

        tasklet_kill(&local->tx_pending_tasklet);
        tasklet_kill(&local->tasklet);

        pm_qos_remove_notifier(PM_QOS_NETWORK_LATENCY,
                               &local->network_latency_notifier);
#ifdef CONFIG_INET
        unregister_inetaddr_notifier(&local->ifa_notifier);
#endif

        rtnl_lock();

        /*
         * At this point, interface list manipulations are fine
         * because the driver cannot be handing us frames any
         * more and the tasklet is killed.
         */
        ieee80211_remove_interfaces(local);

        rtnl_unlock();

        /*
         * Now all work items will be gone, but the
         * timer might still be armed, so delete it
         */
        del_timer_sync(&local->work_timer);

        cancel_work_sync(&local->restart_work);
        cancel_work_sync(&local->reconfig_filter);

        ieee80211_clear_tx_pending(local);
        sta_info_stop(local);
        rate_control_deinitialize(local);

        if (skb_queue_len(&local->skb_queue) ||
            skb_queue_len(&local->skb_queue_unreliable))
                wiphy_warn(local->hw.wiphy, "skb_queue not empty\n");
        skb_queue_purge(&local->skb_queue);
        skb_queue_purge(&local->skb_queue_unreliable);
        skb_queue_purge(&local->rx_skb_queue);

        destroy_workqueue(local->workqueue);
        wiphy_unregister(local->hw.wiphy);
        ieee80211_wep_free(local);
        ieee80211_led_exit(local);
        kfree(local->int_scan_req);
}
EXPORT_SYMBOL(ieee80211_unregister_hw);

void ieee80211_free_hw(struct ieee80211_hw *hw)
{
        struct ieee80211_local *local = hw_to_local(hw);

        mutex_destroy(&local->iflist_mtx);
        mutex_destroy(&local->mtx);

        if (local->wiphy_ciphers_allocated)
                kfree(local->hw.wiphy->cipher_suites);

        wiphy_free(local->hw.wiphy);
}
EXPORT_SYMBOL(ieee80211_free_hw);

static int __init ieee80211_init(void)
{
        struct sk_buff *skb;
        int ret;

        BUILD_BUG_ON(sizeof(struct ieee80211_tx_info) > sizeof(skb->cb));
        BUILD_BUG_ON(offsetof(struct ieee80211_tx_info, driver_data) +
                     IEEE80211_TX_INFO_DRIVER_DATA_SIZE > sizeof(skb->cb));

        ret = rc80211_minstrel_init();
        if (ret)
                return ret;

        ret = rc80211_minstrel_ht_init();
        if (ret)
                goto err_minstrel;

        ret = rc80211_pid_init();
        if (ret)
                goto err_pid;

        ret = ieee80211_iface_init();
        if (ret)
                goto err_netdev;

        return 0;
 err_netdev:
        rc80211_pid_exit();
 err_pid:
        rc80211_minstrel_ht_exit();
 err_minstrel:
        rc80211_minstrel_exit();

        return ret;
}

static void __exit ieee80211_exit(void)
{
        rc80211_pid_exit();
        rc80211_minstrel_ht_exit();
        rc80211_minstrel_exit();

        if (mesh_allocated)
                ieee80211s_stop();

        ieee80211_iface_exit();
}


subsys_initcall(ieee80211_init);
module_exit(ieee80211_exit);

MODULE_DESCRIPTION("IEEE 802.11 subsystem");
MODULE_LICENSE("GPL");