mac80211: Retry null data frame for power save

[linux-2.6/mini2440.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 <net/ieee80211_radiotap.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/wireless.h>
#include <linux/rtnetlink.h>
#include <linux/bitmap.h>
#include <linux/pm_qos_params.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 "wme.h"
#include "aes_ccm.h"
#include "led.h"
#include "cfg.h"
#include "debugfs.h"
#include "debugfs_netdev.h"

/*
 * For seeing transmitted packets on monitor interfaces
 * we have a radiotap header too.
 */
struct ieee80211_tx_status_rtap_hdr {
        struct ieee80211_radiotap_header hdr;
        u8 rate;
        u8 padding_for_rate;
        __le16 tx_flags;
        u8 data_retries;
} __attribute__ ((packed));


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_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_count, 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);
}

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;

        might_sleep();

        scan_chan = local->scan_channel;

        if (scan_chan) {
                chan = scan_chan;
                channel_type = NL80211_CHAN_NO_HT;
        } else {
                chan = local->oper_channel;
                channel_type = local->oper_channel_type;
        }

        if (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 (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->dev->dev_addr;
        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_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 || !netif_running(sdata->dev) ||
                    test_bit(SCAN_SW_SCANNING, &local->scanning)) {
                        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 =
                                        !!rcu_dereference(sdata->u.ap.beacon);
                                break;
                        case NL80211_IFTYPE_ADHOC:
                                sdata->vif.bss_conf.enable_beacon =
                                        !!rcu_dereference(sdata->u.ibss.presp);
                                break;
                        case NL80211_IFTYPE_MESH_POINT:
                                sdata->vif.bss_conf.enable_beacon = true;
                                break;
                        default:
                                /* not reached */
                                WARN_ON(1);
                                break;
                        }
                }
        }

        drv_bss_info_changed(local, &sdata->vif,
                             &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;
}

void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
                                 struct sk_buff *skb)
{
        struct ieee80211_local *local = hw_to_local(hw);
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        int tmp;

        skb->pkt_type = IEEE80211_TX_STATUS_MSG;
        skb_queue_tail(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS ?
                       &local->skb_queue : &local->skb_queue_unreliable, skb);
        tmp = skb_queue_len(&local->skb_queue) +
                skb_queue_len(&local->skb_queue_unreliable);
        while (tmp > IEEE80211_IRQSAFE_QUEUE_LIMIT &&
               (skb = skb_dequeue(&local->skb_queue_unreliable))) {
                dev_kfree_skb_irq(skb);
                tmp--;
                I802_DEBUG_INC(local->tx_status_drop);
        }
        tasklet_schedule(&local->tasklet);
}
EXPORT_SYMBOL(ieee80211_tx_status_irqsafe);

static void ieee80211_tasklet_handler(unsigned long data)
{
        struct ieee80211_local *local = (struct ieee80211_local *) data;
        struct sk_buff *skb;
        struct ieee80211_ra_tid *ra_tid;

        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;
                case IEEE80211_DELBA_MSG:
                        ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
                        ieee80211_stop_tx_ba_cb(local_to_hw(local),
                                                ra_tid->ra, ra_tid->tid);
                        dev_kfree_skb(skb);
                        break;
                case IEEE80211_ADDBA_MSG:
                        ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
                        ieee80211_start_tx_ba_cb(local_to_hw(local),
                                                 ra_tid->ra, ra_tid->tid);
                        dev_kfree_skb(skb);
                        break ;
                default:
                        WARN(1, "mac80211: Packet is of unknown type %d\n",
                             skb->pkt_type);
                        dev_kfree_skb(skb);
                        break;
                }
        }
}

static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
                                            struct sta_info *sta,
                                            struct sk_buff *skb)
{
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);

        /*
         * XXX: This is temporary!
         *
         *      The problem here is that when we get here, the driver will
         *      quite likely have pretty much overwritten info->control by
         *      using info->driver_data or info->rate_driver_data. Thus,
         *      when passing out the frame to the driver again, we would be
         *      passing completely bogus data since the driver would then
         *      expect a properly filled info->control. In mac80211 itself
         *      the same problem occurs, since we need info->control.vif
         *      internally.
         *
         *      To fix this, we should send the frame through TX processing
         *      again. However, it's not that simple, since the frame will
         *      have been software-encrypted (if applicable) already, and
         *      encrypting it again doesn't do much good. So to properly do
         *      that, we not only have to skip the actual 'raw' encryption
         *      (key selection etc. still has to be done!) but also the
         *      sequence number assignment since that impacts the crypto
         *      encapsulation, of course.
         *
         *      Hence, for now, fix the bug by just dropping the frame.
         */
        goto drop;

        sta->tx_filtered_count++;

        /*
         * Clear the TX filter mask for this STA when sending the next
         * packet. If the STA went to power save mode, this will happen
         * when it wakes up for the next time.
         */
        set_sta_flags(sta, WLAN_STA_CLEAR_PS_FILT);

        /*
         * This code races in the following way:
         *
         *  (1) STA sends frame indicating it will go to sleep and does so
         *  (2) hardware/firmware adds STA to filter list, passes frame up
         *  (3) hardware/firmware processes TX fifo and suppresses a frame
         *  (4) we get TX status before having processed the frame and
         *      knowing that the STA has gone to sleep.
         *
         * This is actually quite unlikely even when both those events are
         * processed from interrupts coming in quickly after one another or
         * even at the same time because we queue both TX status events and
         * RX frames to be processed by a tasklet and process them in the
         * same order that they were received or TX status last. Hence, there
         * is no race as long as the frame RX is processed before the next TX
         * status, which drivers can ensure, see below.
         *
         * Note that this can only happen if the hardware or firmware can
         * actually add STAs to the filter list, if this is done by the
         * driver in response to set_tim() (which will only reduce the race
         * this whole filtering tries to solve, not completely solve it)
         * this situation cannot happen.
         *
         * To completely solve this race drivers need to make sure that they
         *  (a) don't mix the irq-safe/not irq-safe TX status/RX processing
         *      functions and
         *  (b) always process RX events before TX status events if ordering
         *      can be unknown, for example with different interrupt status
         *      bits.
         */
        if (test_sta_flags(sta, WLAN_STA_PS) &&
            skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
                skb_queue_tail(&sta->tx_filtered, skb);
                return;
        }

        if (!test_sta_flags(sta, WLAN_STA_PS) &&
            !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
                /* Software retry the packet once */
                info->flags |= IEEE80211_TX_INTFL_RETRIED;
                ieee80211_add_pending_skb(local, skb);
                return;
        }

 drop:
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
        if (net_ratelimit())
                printk(KERN_DEBUG "%s: dropped TX filtered frame, "
                       "queue_len=%d PS=%d @%lu\n",
                       wiphy_name(local->hw.wiphy),
                       skb_queue_len(&sta->tx_filtered),
                       !!test_sta_flags(sta, WLAN_STA_PS), jiffies);
#endif
        dev_kfree_skb(skb);
}

void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
{
        struct sk_buff *skb2;
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
        struct ieee80211_local *local = hw_to_local(hw);
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        u16 frag, type;
        __le16 fc;
        struct ieee80211_supported_band *sband;
        struct ieee80211_tx_status_rtap_hdr *rthdr;
        struct ieee80211_sub_if_data *sdata;
        struct net_device *prev_dev = NULL;
        struct sta_info *sta;
        int retry_count = -1, i;

        for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
                /* the HW cannot have attempted that rate */
                if (i >= hw->max_rates) {
                        info->status.rates[i].idx = -1;
                        info->status.rates[i].count = 0;
                }

                retry_count += info->status.rates[i].count;
        }
        if (retry_count < 0)
                retry_count = 0;

        rcu_read_lock();

        sband = local->hw.wiphy->bands[info->band];
        fc = hdr->frame_control;

        sta = sta_info_get(local, hdr->addr1);

        if (sta) {
                if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
                    test_sta_flags(sta, WLAN_STA_PS)) {
                        /*
                         * The STA is in power save mode, so assume
                         * that this TX packet failed because of that.
                         */
                        ieee80211_handle_filtered_frame(local, sta, skb);
                        rcu_read_unlock();
                        return;
                }

                fc = hdr->frame_control;

                if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
                    (ieee80211_is_data_qos(fc))) {
                        u16 tid, ssn;
                        u8 *qc;

                        qc = ieee80211_get_qos_ctl(hdr);
                        tid = qc[0] & 0xf;
                        ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
                                                & IEEE80211_SCTL_SEQ);
                        ieee80211_send_bar(sta->sdata, hdr->addr1,
                                           tid, ssn);
                }

                if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
                        ieee80211_handle_filtered_frame(local, sta, skb);
                        rcu_read_unlock();
                        return;
                } else {
                        if (!(info->flags & IEEE80211_TX_STAT_ACK))
                                sta->tx_retry_failed++;
                        sta->tx_retry_count += retry_count;
                }

                rate_control_tx_status(local, sband, sta, skb);
                if (ieee80211_vif_is_mesh(&sta->sdata->vif))
                        ieee80211s_update_metric(local, sta, skb);
        }

        rcu_read_unlock();

        ieee80211_led_tx(local, 0);

        /* SNMP counters
         * Fragments are passed to low-level drivers as separate skbs, so these
         * are actually fragments, not frames. Update frame counters only for
         * the first fragment of the frame. */

        frag = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG;
        type = le16_to_cpu(hdr->frame_control) & IEEE80211_FCTL_FTYPE;

        if (info->flags & IEEE80211_TX_STAT_ACK) {
                if (frag == 0) {
                        local->dot11TransmittedFrameCount++;
                        if (is_multicast_ether_addr(hdr->addr1))
                                local->dot11MulticastTransmittedFrameCount++;
                        if (retry_count > 0)
                                local->dot11RetryCount++;
                        if (retry_count > 1)
                                local->dot11MultipleRetryCount++;
                }

                /* This counter shall be incremented for an acknowledged MPDU
                 * with an individual address in the address 1 field or an MPDU
                 * with a multicast address in the address 1 field of type Data
                 * or Management. */
                if (!is_multicast_ether_addr(hdr->addr1) ||
                    type == IEEE80211_FTYPE_DATA ||
                    type == IEEE80211_FTYPE_MGMT)
                        local->dot11TransmittedFragmentCount++;
        } else {
                if (frag == 0)
                        local->dot11FailedCount++;
        }

        if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
            (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) &&
            !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
            local->ps_sdata && !(local->scanning)) {
                if (info->flags & IEEE80211_TX_STAT_ACK) {
                        local->ps_sdata->u.mgd.flags |=
                                IEEE80211_STA_NULLFUNC_ACKED;
                        ieee80211_queue_work(&local->hw,
                                             &local->dynamic_ps_enable_work);
                } else
                        mod_timer(&local->dynamic_ps_timer, jiffies +
                                  msecs_to_jiffies(10));
        }

        /* this was a transmitted frame, but now we want to reuse it */
        skb_orphan(skb);

        /*
         * This is a bit racy but we can avoid a lot of work
         * with this test...
         */
        if (!local->monitors && !local->cooked_mntrs) {
                dev_kfree_skb(skb);
                return;
        }

        /* send frame to monitor interfaces now */

        if (skb_headroom(skb) < sizeof(*rthdr)) {
                printk(KERN_ERR "ieee80211_tx_status: headroom too small\n");
                dev_kfree_skb(skb);
                return;
        }

        rthdr = (struct ieee80211_tx_status_rtap_hdr *)
                                skb_push(skb, sizeof(*rthdr));

        memset(rthdr, 0, sizeof(*rthdr));
        rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
        rthdr->hdr.it_present =
                cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
                            (1 << IEEE80211_RADIOTAP_DATA_RETRIES) |
                            (1 << IEEE80211_RADIOTAP_RATE));

        if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
            !is_multicast_ether_addr(hdr->addr1))
                rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_FAIL);

        /*
         * XXX: Once radiotap gets the bitmap reset thing the vendor
         *      extensions proposal contains, we can actually report
         *      the whole set of tries we did.
         */
        if ((info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) ||
            (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
                rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_CTS);
        else if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
                rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_RTS);
        if (info->status.rates[0].idx >= 0 &&
            !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS))
                rthdr->rate = sband->bitrates[
                                info->status.rates[0].idx].bitrate / 5;

        /* for now report the total retry_count */
        rthdr->data_retries = retry_count;

        /* XXX: is this sufficient for BPF? */
        skb_set_mac_header(skb, 0);
        skb->ip_summed = CHECKSUM_UNNECESSARY;
        skb->pkt_type = PACKET_OTHERHOST;
        skb->protocol = htons(ETH_P_802_2);
        memset(skb->cb, 0, sizeof(skb->cb));

        rcu_read_lock();
        list_for_each_entry_rcu(sdata, &local->interfaces, list) {
                if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
                        if (!netif_running(sdata->dev))
                                continue;

                        if (prev_dev) {
                                skb2 = skb_clone(skb, GFP_ATOMIC);
                                if (skb2) {
                                        skb2->dev = prev_dev;
                                        netif_rx(skb2);
                                }
                        }

                        prev_dev = sdata->dev;
                }
        }
        if (prev_dev) {
                skb->dev = prev_dev;
                netif_rx(skb);
                skb = NULL;
        }
        rcu_read_unlock();
        dev_kfree_skb(skb);
}
EXPORT_SYMBOL(ieee80211_tx_status);

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

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

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

        /* use this reason, __ieee80211_resume will unblock it */
        ieee80211_stop_queues_by_reason(hw,
                IEEE80211_QUEUE_STOP_REASON_SUSPEND);

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

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->netnsok = true;
        wiphy->privid = mac80211_wiphy_privid;

        /* Yes, putting cfg80211_bss into ieee80211_bss is a hack */
        wiphy->bss_priv_size = sizeof(struct ieee80211_bss) -
                               sizeof(struct cfg80211_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.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;

        INIT_LIST_HEAD(&local->interfaces);
        mutex_init(&local->iflist_mtx);
        mutex_init(&local->scan_mtx);

        spin_lock_init(&local->key_lock);
        spin_lock_init(&local->filter_lock);
        spin_lock_init(&local->queue_stop_reason_lock);

        INIT_DELAYED_WORK(&local->scan_work, ieee80211_scan_work);

        INIT_WORK(&local->restart_work, ieee80211_restart_work);

        INIT_WORK(&local->reconfig_filter, ieee80211_reconfig_filter);

        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]);
        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);

        spin_lock_init(&local->ampdu_lock);

        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, i, j, max_bitrates;
        bool supp_ht;
        static const u32 cipher_suites[] = {
                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
        };

        /*
         * 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);

        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;

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

        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--;

        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 =
                create_singlethread_workqueue(wiphy_name(local->hw.wiphy));
        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.
         */
        local->tx_headroom = max_t(unsigned int , local->hw.extra_tx_headroom,
                                   sizeof(struct ieee80211_tx_status_rtap_hdr));

        debugfs_hw_add(local);

        if (local->hw.max_listen_interval == 0)
                local->hw.max_listen_interval = 1;

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

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

        result = ieee80211_wep_init(local);
        if (result < 0) {
                printk(KERN_DEBUG "%s: Failed to initialize wep: %d\n",
                       wiphy_name(local->hw.wiphy), result);
                goto fail_wep;
        }

        rtnl_lock();

        result = ieee80211_init_rate_ctrl_alg(local,
                                              hw->rate_control_algorithm);
        if (result < 0) {
                printk(KERN_DEBUG "%s: Failed to initialize rate control "
                       "algorithm\n", wiphy_name(local->hw.wiphy));
                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)
                        printk(KERN_WARNING "%s: Failed to add default virtual iface\n",
                               wiphy_name(local->hw.wiphy));
        }

        rtnl_unlock();

        ieee80211_led_init(local);

        /* alloc internal scan request */
        i = 0;
        local->int_scan_req->ssids = &local->scan_ssid;
        local->int_scan_req->n_ssids = 1;
        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                if (!hw->wiphy->bands[band])
                        continue;
                for (j = 0; j < hw->wiphy->bands[band]->n_channels; j++) {
                        local->int_scan_req->channels[i] =
                                &hw->wiphy->bands[band]->channels[j];
                        i++;
                }
        }

        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;
        }

        return 0;

 fail_pm_qos:
        ieee80211_led_exit(local);
        ieee80211_remove_interfaces(local);
 fail_rate:
        rtnl_unlock();
        ieee80211_wep_free(local);
 fail_wep:
        sta_info_stop(local);
 fail_sta_info:
        debugfs_hw_del(local);
        destroy_workqueue(local->workqueue);
 fail_workqueue:
        wiphy_unregister(local->hw.wiphy);
 fail_wiphy_register:
        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);

        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();

        cancel_work_sync(&local->reconfig_filter);

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

        if (skb_queue_len(&local->skb_queue)
                        || skb_queue_len(&local->skb_queue_unreliable))
                printk(KERN_WARNING "%s: skb_queue not empty\n",
                       wiphy_name(local->hw.wiphy));
        skb_queue_purge(&local->skb_queue);
        skb_queue_purge(&local->skb_queue_unreliable);

        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->scan_mtx);

        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_pid_init();
        if (ret)
                return ret;

        ieee80211_debugfs_netdev_init();

        return 0;
}

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

        /*
         * For key todo, it'll be empty by now but the work
         * might still be scheduled.
         */
        flush_scheduled_work();

        if (mesh_allocated)
                ieee80211s_stop();

        ieee80211_debugfs_netdev_exit();
}


subsys_initcall(ieee80211_init);
module_exit(ieee80211_exit);

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