mac80211: make retry limits part of hw config

[deliverable/linux.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 <net/net_namespace.h>
#include <net/cfg80211.h>

#include "ieee80211_i.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;
        __le16 tx_flags;
        u8 data_retries;
} __attribute__ ((packed));


/* must be called under mdev tx lock */
void ieee80211_configure_filter(struct ieee80211_local *local)
{
        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)
                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;

        changed_flags = local->filter_flags ^ new_flags;

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

        local->ops->configure_filter(local_to_hw(local),
                                     changed_flags, &new_flags,
                                     local->mdev->mc_count,
                                     local->mdev->mc_list);

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

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

/* master interface */

static int header_parse_80211(const struct sk_buff *skb, unsigned char *haddr)
{
        memcpy(haddr, skb_mac_header(skb) + 10, ETH_ALEN); /* addr2 */
        return ETH_ALEN;
}

static const struct header_ops ieee80211_header_ops = {
        .create         = eth_header,
        .parse          = header_parse_80211,
        .rebuild        = eth_rebuild_header,
        .cache          = eth_header_cache,
        .cache_update   = eth_header_cache_update,
};

static int ieee80211_master_open(struct net_device *dev)
{
        struct ieee80211_master_priv *mpriv = netdev_priv(dev);
        struct ieee80211_local *local = mpriv->local;
        struct ieee80211_sub_if_data *sdata;
        int res = -EOPNOTSUPP;

        /* we hold the RTNL here so can safely walk the list */
        list_for_each_entry(sdata, &local->interfaces, list) {
                if (netif_running(sdata->dev)) {
                        res = 0;
                        break;
                }
        }

        if (res)
                return res;

        netif_tx_start_all_queues(local->mdev);

        return 0;
}

static int ieee80211_master_stop(struct net_device *dev)
{
        struct ieee80211_master_priv *mpriv = netdev_priv(dev);
        struct ieee80211_local *local = mpriv->local;
        struct ieee80211_sub_if_data *sdata;

        /* we hold the RTNL here so can safely walk the list */
        list_for_each_entry(sdata, &local->interfaces, list)
                if (netif_running(sdata->dev))
                        dev_close(sdata->dev);

        return 0;
}

static void ieee80211_master_set_multicast_list(struct net_device *dev)
{
        struct ieee80211_master_priv *mpriv = netdev_priv(dev);
        struct ieee80211_local *local = mpriv->local;

        ieee80211_configure_filter(local);
}

/* everything else */

int ieee80211_if_config(struct ieee80211_sub_if_data *sdata, u32 changed)
{
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_if_conf conf;

        if (WARN_ON(!netif_running(sdata->dev)))
                return 0;

        if (WARN_ON(sdata->vif.type == NL80211_IFTYPE_AP_VLAN))
                return -EINVAL;

        if (!local->ops->config_interface)
                return 0;

        memset(&conf, 0, sizeof(conf));
        conf.changed = changed;

        if (sdata->vif.type == NL80211_IFTYPE_STATION ||
            sdata->vif.type == NL80211_IFTYPE_ADHOC) {
                conf.bssid = sdata->u.sta.bssid;
                conf.ssid = sdata->u.sta.ssid;
                conf.ssid_len = sdata->u.sta.ssid_len;
        } else if (sdata->vif.type == NL80211_IFTYPE_AP) {
                conf.bssid = sdata->dev->dev_addr;
                conf.ssid = sdata->u.ap.ssid;
                conf.ssid_len = sdata->u.ap.ssid_len;
        } else if (ieee80211_vif_is_mesh(&sdata->vif)) {
                u8 zero[ETH_ALEN] = { 0 };
                conf.bssid = zero;
                conf.ssid = zero;
                conf.ssid_len = 0;
        } else {
                WARN_ON(1);
                return -EINVAL;
        }

        if (WARN_ON(!conf.bssid && (changed & IEEE80211_IFCC_BSSID)))
                return -EINVAL;

        if (WARN_ON(!conf.ssid && (changed & IEEE80211_IFCC_SSID)))
                return -EINVAL;

        return local->ops->config_interface(local_to_hw(local),
                                            &sdata->vif, &conf);
}

int ieee80211_hw_config(struct ieee80211_local *local, u32 changed)
{
        struct ieee80211_channel *chan;
        int ret = 0;
        int power;

        if (local->sw_scanning)
                chan = local->scan_channel;
        else
                chan = local->oper_channel;

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


        if (!local->hw.conf.power_level)
                power = chan->max_power;
        else
                power = min(chan->max_power, local->hw.conf.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 = local->ops->config(local_to_hw(local), changed);
                /*
                 * HW reconfiguration should never fail, the driver has told
                 * us what it can support so it should live up to that promise.
                 */
                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;

        if (WARN_ON(sdata->vif.type == NL80211_IFTYPE_AP_VLAN))
                return;

        if (!changed)
                return;

        if (local->ops->bss_info_changed)
                local->ops->bss_info_changed(local_to_hw(local),
                                             &sdata->vif,
                                             &sdata->bss_conf,
                                             changed);
}

u32 ieee80211_reset_erp_info(struct ieee80211_sub_if_data *sdata)
{
        sdata->bss_conf.use_cts_prot = false;
        sdata->bss_conf.use_short_preamble = false;
        sdata->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->dev = local->mdev;
        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_rx_status rx_status;
        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:
                        /* status is in skb->cb */
                        memcpy(&rx_status, skb->cb, sizeof(rx_status));
                        /* Clear skb->pkt_type in order to not confuse kernel
                         * netstack. */
                        skb->pkt_type = 0;
                        __ieee80211_rx(local_to_hw(local), skb, &rx_status);
                        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_ON(1);
                        dev_kfree_skb(skb);
                        break;
                }
        }
}

/* Remove added headers (e.g., QoS control), encryption header/MIC, etc. to
 * make a prepared TX frame (one that has been given to hw) to look like brand
 * new IEEE 802.11 frame that is ready to go through TX processing again.
 */
static void ieee80211_remove_tx_extra(struct ieee80211_local *local,
                                      struct ieee80211_key *key,
                                      struct sk_buff *skb)
{
        unsigned int hdrlen, iv_len, mic_len;
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;

        hdrlen = ieee80211_hdrlen(hdr->frame_control);

        if (!key)
                goto no_key;

        switch (key->conf.alg) {
        case ALG_WEP:
                iv_len = WEP_IV_LEN;
                mic_len = WEP_ICV_LEN;
                break;
        case ALG_TKIP:
                iv_len = TKIP_IV_LEN;
                mic_len = TKIP_ICV_LEN;
                break;
        case ALG_CCMP:
                iv_len = CCMP_HDR_LEN;
                mic_len = CCMP_MIC_LEN;
                break;
        default:
                goto no_key;
        }

        if (skb->len >= hdrlen + mic_len &&
            !(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
                skb_trim(skb, skb->len - mic_len);
        if (skb->len >= hdrlen + iv_len) {
                memmove(skb->data + iv_len, skb->data, hdrlen);
                hdr = (struct ieee80211_hdr *)skb_pull(skb, iv_len);
        }

no_key:
        if (ieee80211_is_data_qos(hdr->frame_control)) {
                hdr->frame_control &= ~cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
                memmove(skb->data + IEEE80211_QOS_CTL_LEN, skb->data,
                        hdrlen - IEEE80211_QOS_CTL_LEN);
                skb_pull(skb, IEEE80211_QOS_CTL_LEN);
        }
}

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);

        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) {
                ieee80211_remove_tx_extra(local, sta->key, skb);
                skb_queue_tail(&sta->tx_filtered, skb);
                return;
        }

        if (!test_sta_flags(sta, WLAN_STA_PS) &&
            !(info->flags & IEEE80211_TX_CTL_REQUEUE)) {
                /* Software retry the packet once */
                info->flags |= IEEE80211_TX_CTL_REQUEUE;
                ieee80211_remove_tx_extra(local, sta->key, skb);
                dev_queue_xmit(skb);
                return;
        }

#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;

        rcu_read_lock();

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

        if (sta) {
                if (info->status.excessive_retries &&
                    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->status.excessive_retries)
                                sta->tx_retry_failed++;
                        sta->tx_retry_count += info->status.retry_count;
                }

                sband = local->hw.wiphy->bands[info->band];
                rate_control_tx_status(local, sband, 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 (info->status.retry_count > 0)
                                local->dot11RetryCount++;
                        if (info->status.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++;
        }

        /* 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));

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

        if ((info->flags & IEEE80211_TX_CTL_USE_RTS_CTS) &&
            (info->flags & IEEE80211_TX_CTL_USE_CTS_PROTECT))
                rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_CTS);
        else if (info->flags & IEEE80211_TX_CTL_USE_RTS_CTS)
                rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_RTS);

        rthdr->data_retries = info->status.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);

struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
                                        const struct ieee80211_ops *ops)
{
        struct ieee80211_local *local;
        int priv_size;
        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 = ((sizeof(struct ieee80211_local) +
                      NETDEV_ALIGN_CONST) & ~NETDEV_ALIGN_CONST) +
                    priv_data_len;

        wiphy = wiphy_new(&mac80211_config_ops, priv_size);

        if (!wiphy)
                return NULL;

        wiphy->privid = mac80211_wiphy_privid;

        local = wiphy_priv(wiphy);
        local->hw.wiphy = wiphy;

        local->hw.priv = (char *)local +
                         ((sizeof(struct ieee80211_local) +
                           NETDEV_ALIGN_CONST) & ~NETDEV_ALIGN_CONST);

        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;

        local->hw.queues = 1; /* default */

        local->rts_threshold = IEEE80211_MAX_RTS_THRESHOLD;
        local->fragmentation_threshold = IEEE80211_MAX_FRAG_THRESHOLD;
        local->hw.conf.long_frame_max_tx_count = 4;
        local->hw.conf.short_frame_max_tx_count = 7;
        local->hw.conf.radio_enabled = true;

        INIT_LIST_HEAD(&local->interfaces);

        spin_lock_init(&local->key_lock);

        INIT_DELAYED_WORK(&local->scan_work, ieee80211_scan_work);

        sta_info_init(local);

        tasklet_init(&local->tx_pending_tasklet, ieee80211_tx_pending,
                     (unsigned long)local);
        tasklet_disable(&local->tx_pending_tasklet);

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

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

        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);
        const char *name;
        int result;
        enum ieee80211_band band;
        struct net_device *mdev;
        struct ieee80211_master_priv *mpriv;

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

                sband = local->hw.wiphy->bands[band];
                if (sband) {
                        /* init channel we're on */
                        local->hw.conf.channel =
                        local->oper_channel =
                        local->scan_channel = &sband->channels[0];
                        break;
                }
        }

        /* 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);

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

        /*
         * 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;
        if (hw->ampdu_queues > IEEE80211_MAX_AMPDU_QUEUES)
                hw->ampdu_queues = IEEE80211_MAX_AMPDU_QUEUES;
        if (hw->queues < 4)
                hw->ampdu_queues = 0;

        mdev = alloc_netdev_mq(sizeof(struct ieee80211_master_priv),
                               "wmaster%d", ether_setup,
                               ieee80211_num_queues(hw));
        if (!mdev)
                goto fail_mdev_alloc;

        mpriv = netdev_priv(mdev);
        mpriv->local = local;
        local->mdev = mdev;

        ieee80211_rx_bss_list_init(local);

        mdev->hard_start_xmit = ieee80211_master_start_xmit;
        mdev->open = ieee80211_master_open;
        mdev->stop = ieee80211_master_stop;
        mdev->type = ARPHRD_IEEE80211;
        mdev->header_ops = &ieee80211_header_ops;
        mdev->set_multicast_list = ieee80211_master_set_multicast_list;

        name = wiphy_dev(local->hw.wiphy)->driver->name;
        local->hw.workqueue = create_freezeable_workqueue(name);
        if (!local->hw.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.conf.beacon_int < 10)
                local->hw.conf.beacon_int = 100;

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

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

        local->wstats_flags |= local->hw.flags & (IEEE80211_HW_SIGNAL_UNSPEC |
                                                  IEEE80211_HW_SIGNAL_DB |
                                                  IEEE80211_HW_SIGNAL_DBM) ?
                               IW_QUAL_QUAL_UPDATED : IW_QUAL_QUAL_INVALID;
        local->wstats_flags |= local->hw.flags & IEEE80211_HW_NOISE_DBM ?
                               IW_QUAL_NOISE_UPDATED : IW_QUAL_NOISE_INVALID;
        if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
                local->wstats_flags |= IW_QUAL_DBM;

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

        rtnl_lock();
        result = dev_alloc_name(local->mdev, local->mdev->name);
        if (result < 0)
                goto fail_dev;

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

        result = register_netdevice(local->mdev);
        if (result < 0)
                goto fail_dev;

        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;
        }

        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;
        }

        local->mdev->select_queue = ieee80211_select_queue;

        /* add one default STA interface */
        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);

        return 0;

fail_wep:
        rate_control_deinitialize(local);
fail_rate:
        unregister_netdevice(local->mdev);
        local->mdev = NULL;
fail_dev:
        rtnl_unlock();
        sta_info_stop(local);
fail_sta_info:
        debugfs_hw_del(local);
        destroy_workqueue(local->hw.workqueue);
fail_workqueue:
        if (local->mdev)
                free_netdev(local->mdev);
fail_mdev_alloc:
        wiphy_unregister(local->hw.wiphy);
        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);

        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.
         */

        /* First, we remove all virtual interfaces. */
        ieee80211_remove_interfaces(local);

        /* then, finally, remove the master interface */
        unregister_netdevice(local->mdev);

        rtnl_unlock();

        ieee80211_rx_bss_list_deinit(local);
        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->hw.workqueue);
        wiphy_unregister(local->hw.wiphy);
        ieee80211_wep_free(local);
        ieee80211_led_exit(local);
        free_netdev(local->mdev);
}
EXPORT_SYMBOL(ieee80211_unregister_hw);

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

        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");