include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit...

[mv-sheeva.git] / net / wireless / reg.c

/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2007       Johannes Berg <johannes@sipsolutions.net>
 * Copyright 2008       Luis R. Rodriguez <lrodriguz@atheros.com>
 *
 * 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.
 */

/**
 * DOC: Wireless regulatory infrastructure
 *
 * The usual implementation is for a driver to read a device EEPROM to
 * determine which regulatory domain it should be operating under, then
 * looking up the allowable channels in a driver-local table and finally
 * registering those channels in the wiphy structure.
 *
 * Another set of compliance enforcement is for drivers to use their
 * own compliance limits which can be stored on the EEPROM. The host
 * driver or firmware may ensure these are used.
 *
 * In addition to all this we provide an extra layer of regulatory
 * conformance. For drivers which do not have any regulatory
 * information CRDA provides the complete regulatory solution.
 * For others it provides a community effort on further restrictions
 * to enhance compliance.
 *
 * Note: When number of rules --> infinity we will not be able to
 * index on alpha2 any more, instead we'll probably have to
 * rely on some SHA1 checksum of the regdomain for example.
 *
 */
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/random.h>
#include <linux/nl80211.h>
#include <linux/platform_device.h>
#include <net/cfg80211.h>
#include "core.h"
#include "reg.h"
#include "regdb.h"
#include "nl80211.h"

#ifdef CONFIG_CFG80211_REG_DEBUG
#define REG_DBG_PRINT(format, args...) \
        do { \
                printk(KERN_DEBUG format , ## args); \
        } while (0)
#else
#define REG_DBG_PRINT(args...)
#endif

/* Receipt of information from last regulatory request */
static struct regulatory_request *last_request;

/* To trigger userspace events */
static struct platform_device *reg_pdev;

/*
 * Central wireless core regulatory domains, we only need two,
 * the current one and a world regulatory domain in case we have no
 * information to give us an alpha2
 */
const struct ieee80211_regdomain *cfg80211_regdomain;

/*
 * We use this as a place for the rd structure built from the
 * last parsed country IE to rest until CRDA gets back to us with
 * what it thinks should apply for the same country
 */
static const struct ieee80211_regdomain *country_ie_regdomain;

/*
 * Protects static reg.c components:
 *     - cfg80211_world_regdom
 *     - cfg80211_regdom
 *     - country_ie_regdomain
 *     - last_request
 */
DEFINE_MUTEX(reg_mutex);
#define assert_reg_lock() WARN_ON(!mutex_is_locked(&reg_mutex))

/* Used to queue up regulatory hints */
static LIST_HEAD(reg_requests_list);
static spinlock_t reg_requests_lock;

/* Used to queue up beacon hints for review */
static LIST_HEAD(reg_pending_beacons);
static spinlock_t reg_pending_beacons_lock;

/* Used to keep track of processed beacon hints */
static LIST_HEAD(reg_beacon_list);

struct reg_beacon {
        struct list_head list;
        struct ieee80211_channel chan;
};

/* We keep a static world regulatory domain in case of the absence of CRDA */
static const struct ieee80211_regdomain world_regdom = {
        .n_reg_rules = 5,
        .alpha2 =  "00",
        .reg_rules = {
                /* IEEE 802.11b/g, channels 1..11 */
                REG_RULE(2412-10, 2462+10, 40, 6, 20, 0),
                /* IEEE 802.11b/g, channels 12..13. No HT40
                 * channel fits here. */
                REG_RULE(2467-10, 2472+10, 20, 6, 20,
                        NL80211_RRF_PASSIVE_SCAN |
                        NL80211_RRF_NO_IBSS),
                /* IEEE 802.11 channel 14 - Only JP enables
                 * this and for 802.11b only */
                REG_RULE(2484-10, 2484+10, 20, 6, 20,
                        NL80211_RRF_PASSIVE_SCAN |
                        NL80211_RRF_NO_IBSS |
                        NL80211_RRF_NO_OFDM),
                /* IEEE 802.11a, channel 36..48 */
                REG_RULE(5180-10, 5240+10, 40, 6, 20,
                        NL80211_RRF_PASSIVE_SCAN |
                        NL80211_RRF_NO_IBSS),

                /* NB: 5260 MHz - 5700 MHz requies DFS */

                /* IEEE 802.11a, channel 149..165 */
                REG_RULE(5745-10, 5825+10, 40, 6, 20,
                        NL80211_RRF_PASSIVE_SCAN |
                        NL80211_RRF_NO_IBSS),
        }
};

static const struct ieee80211_regdomain *cfg80211_world_regdom =
        &world_regdom;

static char *ieee80211_regdom = "00";
static char user_alpha2[2];

module_param(ieee80211_regdom, charp, 0444);
MODULE_PARM_DESC(ieee80211_regdom, "IEEE 802.11 regulatory domain code");

static void reset_regdomains(void)
{
        /* avoid freeing static information or freeing something twice */
        if (cfg80211_regdomain == cfg80211_world_regdom)
                cfg80211_regdomain = NULL;
        if (cfg80211_world_regdom == &world_regdom)
                cfg80211_world_regdom = NULL;
        if (cfg80211_regdomain == &world_regdom)
                cfg80211_regdomain = NULL;

        kfree(cfg80211_regdomain);
        kfree(cfg80211_world_regdom);

        cfg80211_world_regdom = &world_regdom;
        cfg80211_regdomain = NULL;
}

/*
 * Dynamic world regulatory domain requested by the wireless
 * core upon initialization
 */
static void update_world_regdomain(const struct ieee80211_regdomain *rd)
{
        BUG_ON(!last_request);

        reset_regdomains();

        cfg80211_world_regdom = rd;
        cfg80211_regdomain = rd;
}

bool is_world_regdom(const char *alpha2)
{
        if (!alpha2)
                return false;
        if (alpha2[0] == '0' && alpha2[1] == '0')
                return true;
        return false;
}

static bool is_alpha2_set(const char *alpha2)
{
        if (!alpha2)
                return false;
        if (alpha2[0] != 0 && alpha2[1] != 0)
                return true;
        return false;
}

static bool is_alpha_upper(char letter)
{
        /* ASCII A - Z */
        if (letter >= 65 && letter <= 90)
                return true;
        return false;
}

static bool is_unknown_alpha2(const char *alpha2)
{
        if (!alpha2)
                return false;
        /*
         * Special case where regulatory domain was built by driver
         * but a specific alpha2 cannot be determined
         */
        if (alpha2[0] == '9' && alpha2[1] == '9')
                return true;
        return false;
}

static bool is_intersected_alpha2(const char *alpha2)
{
        if (!alpha2)
                return false;
        /*
         * Special case where regulatory domain is the
         * result of an intersection between two regulatory domain
         * structures
         */
        if (alpha2[0] == '9' && alpha2[1] == '8')
                return true;
        return false;
}

static bool is_an_alpha2(const char *alpha2)
{
        if (!alpha2)
                return false;
        if (is_alpha_upper(alpha2[0]) && is_alpha_upper(alpha2[1]))
                return true;
        return false;
}

static bool alpha2_equal(const char *alpha2_x, const char *alpha2_y)
{
        if (!alpha2_x || !alpha2_y)
                return false;
        if (alpha2_x[0] == alpha2_y[0] &&
                alpha2_x[1] == alpha2_y[1])
                return true;
        return false;
}

static bool regdom_changes(const char *alpha2)
{
        assert_cfg80211_lock();

        if (!cfg80211_regdomain)
                return true;
        if (alpha2_equal(cfg80211_regdomain->alpha2, alpha2))
                return false;
        return true;
}

/*
 * The NL80211_REGDOM_SET_BY_USER regdom alpha2 is cached, this lets
 * you know if a valid regulatory hint with NL80211_REGDOM_SET_BY_USER
 * has ever been issued.
 */
static bool is_user_regdom_saved(void)
{
        if (user_alpha2[0] == '9' && user_alpha2[1] == '7')
                return false;

        /* This would indicate a mistake on the design */
        if (WARN((!is_world_regdom(user_alpha2) &&
                  !is_an_alpha2(user_alpha2)),
                 "Unexpected user alpha2: %c%c\n",
                 user_alpha2[0],
                 user_alpha2[1]))
                return false;

        return true;
}

/**
 * country_ie_integrity_changes - tells us if the country IE has changed
 * @checksum: checksum of country IE of fields we are interested in
 *
 * If the country IE has not changed you can ignore it safely. This is
 * useful to determine if two devices are seeing two different country IEs
 * even on the same alpha2. Note that this will return false if no IE has
 * been set on the wireless core yet.
 */
static bool country_ie_integrity_changes(u32 checksum)
{
        /* If no IE has been set then the checksum doesn't change */
        if (unlikely(!last_request->country_ie_checksum))
                return false;
        if (unlikely(last_request->country_ie_checksum != checksum))
                return true;
        return false;
}

static int reg_copy_regd(const struct ieee80211_regdomain **dst_regd,
                         const struct ieee80211_regdomain *src_regd)
{
        struct ieee80211_regdomain *regd;
        int size_of_regd = 0;
        unsigned int i;

        size_of_regd = sizeof(struct ieee80211_regdomain) +
          ((src_regd->n_reg_rules + 1) * sizeof(struct ieee80211_reg_rule));

        regd = kzalloc(size_of_regd, GFP_KERNEL);
        if (!regd)
                return -ENOMEM;

        memcpy(regd, src_regd, sizeof(struct ieee80211_regdomain));

        for (i = 0; i < src_regd->n_reg_rules; i++)
                memcpy(&regd->reg_rules[i], &src_regd->reg_rules[i],
                        sizeof(struct ieee80211_reg_rule));

        *dst_regd = regd;
        return 0;
}

#ifdef CONFIG_CFG80211_INTERNAL_REGDB
struct reg_regdb_search_request {
        char alpha2[2];
        struct list_head list;
};

static LIST_HEAD(reg_regdb_search_list);
static DEFINE_SPINLOCK(reg_regdb_search_lock);

static void reg_regdb_search(struct work_struct *work)
{
        struct reg_regdb_search_request *request;
        const struct ieee80211_regdomain *curdom, *regdom;
        int i, r;

        spin_lock(&reg_regdb_search_lock);
        while (!list_empty(&reg_regdb_search_list)) {
                request = list_first_entry(&reg_regdb_search_list,
                                           struct reg_regdb_search_request,
                                           list);
                list_del(&request->list);

                for (i=0; i<reg_regdb_size; i++) {
                        curdom = reg_regdb[i];

                        if (!memcmp(request->alpha2, curdom->alpha2, 2)) {
                                r = reg_copy_regd(&regdom, curdom);
                                if (r)
                                        break;
                                spin_unlock(&reg_regdb_search_lock);
                                mutex_lock(&cfg80211_mutex);
                                set_regdom(regdom);
                                mutex_unlock(&cfg80211_mutex);
                                spin_lock(&reg_regdb_search_lock);
                                break;
                        }
                }

                kfree(request);
        }
        spin_unlock(&reg_regdb_search_lock);
}

static DECLARE_WORK(reg_regdb_work, reg_regdb_search);

static void reg_regdb_query(const char *alpha2)
{
        struct reg_regdb_search_request *request;

        if (!alpha2)
                return;

        request = kzalloc(sizeof(struct reg_regdb_search_request), GFP_KERNEL);
        if (!request)
                return;

        memcpy(request->alpha2, alpha2, 2);

        spin_lock(&reg_regdb_search_lock);
        list_add_tail(&request->list, &reg_regdb_search_list);
        spin_unlock(&reg_regdb_search_lock);

        schedule_work(&reg_regdb_work);
}
#else
static inline void reg_regdb_query(const char *alpha2) {}
#endif /* CONFIG_CFG80211_INTERNAL_REGDB */

/*
 * This lets us keep regulatory code which is updated on a regulatory
 * basis in userspace.
 */
static int call_crda(const char *alpha2)
{
        char country_env[9 + 2] = "COUNTRY=";
        char *envp[] = {
                country_env,
                NULL
        };

        if (!is_world_regdom((char *) alpha2))
                printk(KERN_INFO "cfg80211: Calling CRDA for country: %c%c\n",
                        alpha2[0], alpha2[1]);
        else
                printk(KERN_INFO "cfg80211: Calling CRDA to update world "
                        "regulatory domain\n");

        /* query internal regulatory database (if it exists) */
        reg_regdb_query(alpha2);

        country_env[8] = alpha2[0];
        country_env[9] = alpha2[1];

        return kobject_uevent_env(&reg_pdev->dev.kobj, KOBJ_CHANGE, envp);
}

/* Used by nl80211 before kmalloc'ing our regulatory domain */
bool reg_is_valid_request(const char *alpha2)
{
        assert_cfg80211_lock();

        if (!last_request)
                return false;

        return alpha2_equal(last_request->alpha2, alpha2);
}

/* Sanity check on a regulatory rule */
static bool is_valid_reg_rule(const struct ieee80211_reg_rule *rule)
{
        const struct ieee80211_freq_range *freq_range = &rule->freq_range;
        u32 freq_diff;

        if (freq_range->start_freq_khz <= 0 || freq_range->end_freq_khz <= 0)
                return false;

        if (freq_range->start_freq_khz > freq_range->end_freq_khz)
                return false;

        freq_diff = freq_range->end_freq_khz - freq_range->start_freq_khz;

        if (freq_range->end_freq_khz <= freq_range->start_freq_khz ||
                        freq_range->max_bandwidth_khz > freq_diff)
                return false;

        return true;
}

static bool is_valid_rd(const struct ieee80211_regdomain *rd)
{
        const struct ieee80211_reg_rule *reg_rule = NULL;
        unsigned int i;

        if (!rd->n_reg_rules)
                return false;

        if (WARN_ON(rd->n_reg_rules > NL80211_MAX_SUPP_REG_RULES))
                return false;

        for (i = 0; i < rd->n_reg_rules; i++) {
                reg_rule = &rd->reg_rules[i];
                if (!is_valid_reg_rule(reg_rule))
                        return false;
        }

        return true;
}

static bool reg_does_bw_fit(const struct ieee80211_freq_range *freq_range,
                            u32 center_freq_khz,
                            u32 bw_khz)
{
        u32 start_freq_khz, end_freq_khz;

        start_freq_khz = center_freq_khz - (bw_khz/2);
        end_freq_khz = center_freq_khz + (bw_khz/2);

        if (start_freq_khz >= freq_range->start_freq_khz &&
            end_freq_khz <= freq_range->end_freq_khz)
                return true;

        return false;
}

/**
 * freq_in_rule_band - tells us if a frequency is in a frequency band
 * @freq_range: frequency rule we want to query
 * @freq_khz: frequency we are inquiring about
 *
 * This lets us know if a specific frequency rule is or is not relevant to
 * a specific frequency's band. Bands are device specific and artificial
 * definitions (the "2.4 GHz band" and the "5 GHz band"), however it is
 * safe for now to assume that a frequency rule should not be part of a
 * frequency's band if the start freq or end freq are off by more than 2 GHz.
 * This resolution can be lowered and should be considered as we add
 * regulatory rule support for other "bands".
 **/
static bool freq_in_rule_band(const struct ieee80211_freq_range *freq_range,
        u32 freq_khz)
{
#define ONE_GHZ_IN_KHZ  1000000
        if (abs(freq_khz - freq_range->start_freq_khz) <= (2 * ONE_GHZ_IN_KHZ))
                return true;
        if (abs(freq_khz - freq_range->end_freq_khz) <= (2 * ONE_GHZ_IN_KHZ))
                return true;
        return false;
#undef ONE_GHZ_IN_KHZ
}

/*
 * This is a work around for sanity checking ieee80211_channel_to_frequency()'s
 * work. ieee80211_channel_to_frequency() can for example currently provide a
 * 2 GHz channel when in fact a 5 GHz channel was desired. An example would be
 * an AP providing channel 8 on a country IE triplet when it sent this on the
 * 5 GHz band, that channel is designed to be channel 8 on 5 GHz, not a 2 GHz
 * channel.
 *
 * This can be removed once ieee80211_channel_to_frequency() takes in a band.
 */
static bool chan_in_band(int chan, enum ieee80211_band band)
{
        int center_freq = ieee80211_channel_to_frequency(chan);

        switch (band) {
        case IEEE80211_BAND_2GHZ:
                if (center_freq <= 2484)
                        return true;
                return false;
        case IEEE80211_BAND_5GHZ:
                if (center_freq >= 5005)
                        return true;
                return false;
        default:
                return false;
        }
}

/*
 * Some APs may send a country IE triplet for each channel they
 * support and while this is completely overkill and silly we still
 * need to support it. We avoid making a single rule for each channel
 * though and to help us with this we use this helper to find the
 * actual subband end channel. These type of country IE triplet
 * scenerios are handled then, all yielding two regulaotry rules from
 * parsing a country IE:
 *
 * [1]
 * [2]
 * [36]
 * [40]
 *
 * [1]
 * [2-4]
 * [5-12]
 * [36]
 * [40-44]
 *
 * [1-4]
 * [5-7]
 * [36-44]
 * [48-64]
 *
 * [36-36]
 * [40-40]
 * [44-44]
 * [48-48]
 * [52-52]
 * [56-56]
 * [60-60]
 * [64-64]
 * [100-100]
 * [104-104]
 * [108-108]
 * [112-112]
 * [116-116]
 * [120-120]
 * [124-124]
 * [128-128]
 * [132-132]
 * [136-136]
 * [140-140]
 *
 * Returns 0 if the IE has been found to be invalid in the middle
 * somewhere.
 */
static int max_subband_chan(enum ieee80211_band band,
                            int orig_cur_chan,
                            int orig_end_channel,
                            s8 orig_max_power,
                            u8 **country_ie,
                            u8 *country_ie_len)
{
        u8 *triplets_start = *country_ie;
        u8 len_at_triplet = *country_ie_len;
        int end_subband_chan = orig_end_channel;

        /*
         * We'll deal with padding for the caller unless
         * its not immediate and we don't process any channels
         */
        if (*country_ie_len == 1) {
                *country_ie += 1;
                *country_ie_len -= 1;
                return orig_end_channel;
        }

        /* Move to the next triplet and then start search */
        *country_ie += 3;
        *country_ie_len -= 3;

        if (!chan_in_band(orig_cur_chan, band))
                return 0;

        while (*country_ie_len >= 3) {
                int end_channel = 0;
                struct ieee80211_country_ie_triplet *triplet =
                        (struct ieee80211_country_ie_triplet *) *country_ie;
                int cur_channel = 0, next_expected_chan;

                /* means last triplet is completely unrelated to this one */
                if (triplet->ext.reg_extension_id >=
                                IEEE80211_COUNTRY_EXTENSION_ID) {
                        *country_ie -= 3;
                        *country_ie_len += 3;
                        break;
                }

                if (triplet->chans.first_channel == 0) {
                        *country_ie += 1;
                        *country_ie_len -= 1;
                        if (*country_ie_len != 0)
                                return 0;
                        break;
                }

                if (triplet->chans.num_channels == 0)
                        return 0;

                /* Monitonically increasing channel order */
                if (triplet->chans.first_channel <= end_subband_chan)
                        return 0;

                if (!chan_in_band(triplet->chans.first_channel, band))
                        return 0;

                /* 2 GHz */
                if (triplet->chans.first_channel <= 14) {
                        end_channel = triplet->chans.first_channel +
                                triplet->chans.num_channels - 1;
                }
                else {
                        end_channel =  triplet->chans.first_channel +
                                (4 * (triplet->chans.num_channels - 1));
                }

                if (!chan_in_band(end_channel, band))
                        return 0;

                if (orig_max_power != triplet->chans.max_power) {
                        *country_ie -= 3;
                        *country_ie_len += 3;
                        break;
                }

                cur_channel = triplet->chans.first_channel;

                /* The key is finding the right next expected channel */
                if (band == IEEE80211_BAND_2GHZ)
                        next_expected_chan = end_subband_chan + 1;
                 else
                        next_expected_chan = end_subband_chan + 4;

                if (cur_channel != next_expected_chan) {
                        *country_ie -= 3;
                        *country_ie_len += 3;
                        break;
                }

                end_subband_chan = end_channel;

                /* Move to the next one */
                *country_ie += 3;
                *country_ie_len -= 3;

                /*
                 * Padding needs to be dealt with if we processed
                 * some channels.
                 */
                if (*country_ie_len == 1) {
                        *country_ie += 1;
                        *country_ie_len -= 1;
                        break;
                }

                /* If seen, the IE is invalid */
                if (*country_ie_len == 2)
                        return 0;
        }

        if (end_subband_chan == orig_end_channel) {
                *country_ie = triplets_start;
                *country_ie_len = len_at_triplet;
                return orig_end_channel;
        }

        return end_subband_chan;
}

/*
 * Converts a country IE to a regulatory domain. A regulatory domain
 * structure has a lot of information which the IE doesn't yet have,
 * so for the other values we use upper max values as we will intersect
 * with our userspace regulatory agent to get lower bounds.
 */
static struct ieee80211_regdomain *country_ie_2_rd(
                                enum ieee80211_band band,
                                u8 *country_ie,
                                u8 country_ie_len,
                                u32 *checksum)
{
        struct ieee80211_regdomain *rd = NULL;
        unsigned int i = 0;
        char alpha2[2];
        u32 flags = 0;
        u32 num_rules = 0, size_of_regd = 0;
        u8 *triplets_start = NULL;
        u8 len_at_triplet = 0;
        /* the last channel we have registered in a subband (triplet) */
        int last_sub_max_channel = 0;

        *checksum = 0xDEADBEEF;

        /* Country IE requirements */
        BUG_ON(country_ie_len < IEEE80211_COUNTRY_IE_MIN_LEN ||
                country_ie_len & 0x01);

        alpha2[0] = country_ie[0];
        alpha2[1] = country_ie[1];

        /*
         * Third octet can be:
         *    'I' - Indoor
         *    'O' - Outdoor
         *
         *  anything else we assume is no restrictions
         */
        if (country_ie[2] == 'I')
                flags = NL80211_RRF_NO_OUTDOOR;
        else if (country_ie[2] == 'O')
                flags = NL80211_RRF_NO_INDOOR;

        country_ie += 3;
        country_ie_len -= 3;

        triplets_start = country_ie;
        len_at_triplet = country_ie_len;

        *checksum ^= ((flags ^ alpha2[0] ^ alpha2[1]) << 8);

        /*
         * We need to build a reg rule for each triplet, but first we must
         * calculate the number of reg rules we will need. We will need one
         * for each channel subband
         */
        while (country_ie_len >= 3) {
                int end_channel = 0;
                struct ieee80211_country_ie_triplet *triplet =
                        (struct ieee80211_country_ie_triplet *) country_ie;
                int cur_sub_max_channel = 0, cur_channel = 0;

                if (triplet->ext.reg_extension_id >=
                                IEEE80211_COUNTRY_EXTENSION_ID) {
                        country_ie += 3;
                        country_ie_len -= 3;
                        continue;
                }

                /*
                 * APs can add padding to make length divisible
                 * by two, required by the spec.
                 */
                if (triplet->chans.first_channel == 0) {
                        country_ie++;
                        country_ie_len--;
                        /* This is expected to be at the very end only */
                        if (country_ie_len != 0)
                                return NULL;
                        break;
                }

                if (triplet->chans.num_channels == 0)
                        return NULL;

                if (!chan_in_band(triplet->chans.first_channel, band))
                        return NULL;

                /* 2 GHz */
                if (band == IEEE80211_BAND_2GHZ)
                        end_channel = triplet->chans.first_channel +
                                triplet->chans.num_channels - 1;
                else
                        /*
                         * 5 GHz -- For example in country IEs if the first
                         * channel given is 36 and the number of channels is 4
                         * then the individual channel numbers defined for the
                         * 5 GHz PHY by these parameters are: 36, 40, 44, and 48
                         * and not 36, 37, 38, 39.
                         *
                         * See: http://tinyurl.com/11d-clarification
                         */
                        end_channel =  triplet->chans.first_channel +
                                (4 * (triplet->chans.num_channels - 1));

                cur_channel = triplet->chans.first_channel;

                /*
                 * Enhancement for APs that send a triplet for every channel
                 * or for whatever reason sends triplets with multiple channels
                 * separated when in fact they should be together.
                 */
                end_channel = max_subband_chan(band,
                                               cur_channel,
                                               end_channel,
                                               triplet->chans.max_power,
                                               &country_ie,
                                               &country_ie_len);
                if (!end_channel)
                        return NULL;

                if (!chan_in_band(end_channel, band))
                        return NULL;

                cur_sub_max_channel = end_channel;

                /* Basic sanity check */
                if (cur_sub_max_channel < cur_channel)
                        return NULL;

                /*
                 * Do not allow overlapping channels. Also channels
                 * passed in each subband must be monotonically
                 * increasing
                 */
                if (last_sub_max_channel) {
                        if (cur_channel <= last_sub_max_channel)
                                return NULL;
                        if (cur_sub_max_channel <= last_sub_max_channel)
                                return NULL;
                }

                /*
                 * When dot11RegulatoryClassesRequired is supported
                 * we can throw ext triplets as part of this soup,
                 * for now we don't care when those change as we
                 * don't support them
                 */
                *checksum ^= ((cur_channel ^ cur_sub_max_channel) << 8) |
                  ((cur_sub_max_channel ^ cur_sub_max_channel) << 16) |
                  ((triplet->chans.max_power ^ cur_sub_max_channel) << 24);

                last_sub_max_channel = cur_sub_max_channel;

                num_rules++;

                if (country_ie_len >= 3) {
                        country_ie += 3;
                        country_ie_len -= 3;
                }

                /*
                 * Note: this is not a IEEE requirement but
                 * simply a memory requirement
                 */
                if (num_rules > NL80211_MAX_SUPP_REG_RULES)
                        return NULL;
        }

        country_ie = triplets_start;
        country_ie_len = len_at_triplet;

        size_of_regd = sizeof(struct ieee80211_regdomain) +
                (num_rules * sizeof(struct ieee80211_reg_rule));

        rd = kzalloc(size_of_regd, GFP_KERNEL);
        if (!rd)
                return NULL;

        rd->n_reg_rules = num_rules;
        rd->alpha2[0] = alpha2[0];
        rd->alpha2[1] = alpha2[1];

        /* This time around we fill in the rd */
        while (country_ie_len >= 3) {
                int end_channel = 0;
                struct ieee80211_country_ie_triplet *triplet =
                        (struct ieee80211_country_ie_triplet *) country_ie;
                struct ieee80211_reg_rule *reg_rule = NULL;
                struct ieee80211_freq_range *freq_range = NULL;
                struct ieee80211_power_rule *power_rule = NULL;

                /*
                 * Must parse if dot11RegulatoryClassesRequired is true,
                 * we don't support this yet
                 */
                if (triplet->ext.reg_extension_id >=
                                IEEE80211_COUNTRY_EXTENSION_ID) {
                        country_ie += 3;
                        country_ie_len -= 3;
                        continue;
                }

                if (triplet->chans.first_channel == 0) {
                        country_ie++;
                        country_ie_len--;
                        break;
                }

                reg_rule = &rd->reg_rules[i];
                freq_range = &reg_rule->freq_range;
                power_rule = &reg_rule->power_rule;

                reg_rule->flags = flags;

                /* 2 GHz */
                if (band == IEEE80211_BAND_2GHZ)
                        end_channel = triplet->chans.first_channel +
                                triplet->chans.num_channels -1;
                else
                        end_channel =  triplet->chans.first_channel +
                                (4 * (triplet->chans.num_channels - 1));

                end_channel = max_subband_chan(band,
                                               triplet->chans.first_channel,
                                               end_channel,
                                               triplet->chans.max_power,
                                               &country_ie,
                                               &country_ie_len);

                /*
                 * The +10 is since the regulatory domain expects
                 * the actual band edge, not the center of freq for
                 * its start and end freqs, assuming 20 MHz bandwidth on
                 * the channels passed
                 */
                freq_range->start_freq_khz =
                        MHZ_TO_KHZ(ieee80211_channel_to_frequency(
                                triplet->chans.first_channel) - 10);
                freq_range->end_freq_khz =
                        MHZ_TO_KHZ(ieee80211_channel_to_frequency(
                                end_channel) + 10);

                /*
                 * These are large arbitrary values we use to intersect later.
                 * Increment this if we ever support >= 40 MHz channels
                 * in IEEE 802.11
                 */
                freq_range->max_bandwidth_khz = MHZ_TO_KHZ(40);
                power_rule->max_antenna_gain = DBI_TO_MBI(100);
                power_rule->max_eirp = DBM_TO_MBM(triplet->chans.max_power);

                i++;

                if (country_ie_len >= 3) {
                        country_ie += 3;
                        country_ie_len -= 3;
                }

                BUG_ON(i > NL80211_MAX_SUPP_REG_RULES);
        }

        return rd;
}


/*
 * Helper for regdom_intersect(), this does the real
 * mathematical intersection fun
 */
static int reg_rules_intersect(
        const struct ieee80211_reg_rule *rule1,
        const struct ieee80211_reg_rule *rule2,
        struct ieee80211_reg_rule *intersected_rule)
{
        const struct ieee80211_freq_range *freq_range1, *freq_range2;
        struct ieee80211_freq_range *freq_range;
        const struct ieee80211_power_rule *power_rule1, *power_rule2;
        struct ieee80211_power_rule *power_rule;
        u32 freq_diff;

        freq_range1 = &rule1->freq_range;
        freq_range2 = &rule2->freq_range;
        freq_range = &intersected_rule->freq_range;

        power_rule1 = &rule1->power_rule;
        power_rule2 = &rule2->power_rule;
        power_rule = &intersected_rule->power_rule;

        freq_range->start_freq_khz = max(freq_range1->start_freq_khz,
                freq_range2->start_freq_khz);
        freq_range->end_freq_khz = min(freq_range1->end_freq_khz,
                freq_range2->end_freq_khz);
        freq_range->max_bandwidth_khz = min(freq_range1->max_bandwidth_khz,
                freq_range2->max_bandwidth_khz);

        freq_diff = freq_range->end_freq_khz - freq_range->start_freq_khz;
        if (freq_range->max_bandwidth_khz > freq_diff)
                freq_range->max_bandwidth_khz = freq_diff;

        power_rule->max_eirp = min(power_rule1->max_eirp,
                power_rule2->max_eirp);
        power_rule->max_antenna_gain = min(power_rule1->max_antenna_gain,
                power_rule2->max_antenna_gain);

        intersected_rule->flags = (rule1->flags | rule2->flags);

        if (!is_valid_reg_rule(intersected_rule))
                return -EINVAL;

        return 0;
}

/**
 * regdom_intersect - do the intersection between two regulatory domains
 * @rd1: first regulatory domain
 * @rd2: second regulatory domain
 *
 * Use this function to get the intersection between two regulatory domains.
 * Once completed we will mark the alpha2 for the rd as intersected, "98",
 * as no one single alpha2 can represent this regulatory domain.
 *
 * Returns a pointer to the regulatory domain structure which will hold the
 * resulting intersection of rules between rd1 and rd2. We will
 * kzalloc() this structure for you.
 */
static struct ieee80211_regdomain *regdom_intersect(
        const struct ieee80211_regdomain *rd1,
        const struct ieee80211_regdomain *rd2)
{
        int r, size_of_regd;
        unsigned int x, y;
        unsigned int num_rules = 0, rule_idx = 0;
        const struct ieee80211_reg_rule *rule1, *rule2;
        struct ieee80211_reg_rule *intersected_rule;
        struct ieee80211_regdomain *rd;
        /* This is just a dummy holder to help us count */
        struct ieee80211_reg_rule irule;

        /* Uses the stack temporarily for counter arithmetic */
        intersected_rule = &irule;

        memset(intersected_rule, 0, sizeof(struct ieee80211_reg_rule));

        if (!rd1 || !rd2)
                return NULL;

        /*
         * First we get a count of the rules we'll need, then we actually
         * build them. This is to so we can malloc() and free() a
         * regdomain once. The reason we use reg_rules_intersect() here
         * is it will return -EINVAL if the rule computed makes no sense.
         * All rules that do check out OK are valid.
         */

        for (x = 0; x < rd1->n_reg_rules; x++) {
                rule1 = &rd1->reg_rules[x];
                for (y = 0; y < rd2->n_reg_rules; y++) {
                        rule2 = &rd2->reg_rules[y];
                        if (!reg_rules_intersect(rule1, rule2,
                                        intersected_rule))
                                num_rules++;
                        memset(intersected_rule, 0,
                                        sizeof(struct ieee80211_reg_rule));
                }
        }

        if (!num_rules)
                return NULL;

        size_of_regd = sizeof(struct ieee80211_regdomain) +
                ((num_rules + 1) * sizeof(struct ieee80211_reg_rule));

        rd = kzalloc(size_of_regd, GFP_KERNEL);
        if (!rd)
                return NULL;

        for (x = 0; x < rd1->n_reg_rules; x++) {
                rule1 = &rd1->reg_rules[x];
                for (y = 0; y < rd2->n_reg_rules; y++) {
                        rule2 = &rd2->reg_rules[y];
                        /*
                         * This time around instead of using the stack lets
                         * write to the target rule directly saving ourselves
                         * a memcpy()
                         */
                        intersected_rule = &rd->reg_rules[rule_idx];
                        r = reg_rules_intersect(rule1, rule2,
                                intersected_rule);
                        /*
                         * No need to memset here the intersected rule here as
                         * we're not using the stack anymore
                         */
                        if (r)
                                continue;
                        rule_idx++;
                }
        }

        if (rule_idx != num_rules) {
                kfree(rd);
                return NULL;
        }

        rd->n_reg_rules = num_rules;
        rd->alpha2[0] = '9';
        rd->alpha2[1] = '8';

        return rd;
}

/*
 * XXX: add support for the rest of enum nl80211_reg_rule_flags, we may
 * want to just have the channel structure use these
 */
static u32 map_regdom_flags(u32 rd_flags)
{
        u32 channel_flags = 0;
        if (rd_flags & NL80211_RRF_PASSIVE_SCAN)
                channel_flags |= IEEE80211_CHAN_PASSIVE_SCAN;
        if (rd_flags & NL80211_RRF_NO_IBSS)
                channel_flags |= IEEE80211_CHAN_NO_IBSS;
        if (rd_flags & NL80211_RRF_DFS)
                channel_flags |= IEEE80211_CHAN_RADAR;
        return channel_flags;
}

static int freq_reg_info_regd(struct wiphy *wiphy,
                              u32 center_freq,
                              u32 desired_bw_khz,
                              const struct ieee80211_reg_rule **reg_rule,
                              const struct ieee80211_regdomain *custom_regd)
{
        int i;
        bool band_rule_found = false;
        const struct ieee80211_regdomain *regd;
        bool bw_fits = false;

        if (!desired_bw_khz)
                desired_bw_khz = MHZ_TO_KHZ(20);

        regd = custom_regd ? custom_regd : cfg80211_regdomain;

        /*
         * Follow the driver's regulatory domain, if present, unless a country
         * IE has been processed or a user wants to help complaince further
         */
        if (last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&
            last_request->initiator != NL80211_REGDOM_SET_BY_USER &&
            wiphy->regd)
                regd = wiphy->regd;

        if (!regd)
                return -EINVAL;

        for (i = 0; i < regd->n_reg_rules; i++) {
                const struct ieee80211_reg_rule *rr;
                const struct ieee80211_freq_range *fr = NULL;
                const struct ieee80211_power_rule *pr = NULL;

                rr = &regd->reg_rules[i];
                fr = &rr->freq_range;
                pr = &rr->power_rule;

                /*
                 * We only need to know if one frequency rule was
                 * was in center_freq's band, that's enough, so lets
                 * not overwrite it once found
                 */
                if (!band_rule_found)
                        band_rule_found = freq_in_rule_band(fr, center_freq);

                bw_fits = reg_does_bw_fit(fr,
                                          center_freq,
                                          desired_bw_khz);

                if (band_rule_found && bw_fits) {
                        *reg_rule = rr;
                        return 0;
                }
        }

        if (!band_rule_found)
                return -ERANGE;

        return -EINVAL;
}
EXPORT_SYMBOL(freq_reg_info);

int freq_reg_info(struct wiphy *wiphy,
                  u32 center_freq,
                  u32 desired_bw_khz,
                  const struct ieee80211_reg_rule **reg_rule)
{
        assert_cfg80211_lock();
        return freq_reg_info_regd(wiphy,
                                  center_freq,
                                  desired_bw_khz,
                                  reg_rule,
                                  NULL);
}

/*
 * Note that right now we assume the desired channel bandwidth
 * is always 20 MHz for each individual channel (HT40 uses 20 MHz
 * per channel, the primary and the extension channel). To support
 * smaller custom bandwidths such as 5 MHz or 10 MHz we'll need a
 * new ieee80211_channel.target_bw and re run the regulatory check
 * on the wiphy with the target_bw specified. Then we can simply use
 * that below for the desired_bw_khz below.
 */
static void handle_channel(struct wiphy *wiphy, enum ieee80211_band band,
                           unsigned int chan_idx)
{
        int r;
        u32 flags, bw_flags = 0;
        u32 desired_bw_khz = MHZ_TO_KHZ(20);
        const struct ieee80211_reg_rule *reg_rule = NULL;
        const struct ieee80211_power_rule *power_rule = NULL;
        const struct ieee80211_freq_range *freq_range = NULL;
        struct ieee80211_supported_band *sband;
        struct ieee80211_channel *chan;
        struct wiphy *request_wiphy = NULL;

        assert_cfg80211_lock();

        request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx);

        sband = wiphy->bands[band];
        BUG_ON(chan_idx >= sband->n_channels);
        chan = &sband->channels[chan_idx];

        flags = chan->orig_flags;

        r = freq_reg_info(wiphy,
                          MHZ_TO_KHZ(chan->center_freq),
                          desired_bw_khz,
                          &reg_rule);

        if (r) {
                /*
                 * This means no regulatory rule was found in the country IE
                 * with a frequency range on the center_freq's band, since
                 * IEEE-802.11 allows for a country IE to have a subset of the
                 * regulatory information provided in a country we ignore
                 * disabling the channel unless at least one reg rule was
                 * found on the center_freq's band. For details see this
                 * clarification:
                 *
                 * http://tinyurl.com/11d-clarification
                 */
                if (r == -ERANGE &&
                    last_request->initiator ==
                    NL80211_REGDOM_SET_BY_COUNTRY_IE) {
                        REG_DBG_PRINT("cfg80211: Leaving channel %d MHz "
                                "intact on %s - no rule found in band on "
                                "Country IE\n",
                        chan->center_freq, wiphy_name(wiphy));
                } else {
                /*
                 * In this case we know the country IE has at least one reg rule
                 * for the band so we respect its band definitions
                 */
                        if (last_request->initiator ==
                            NL80211_REGDOM_SET_BY_COUNTRY_IE)
                                REG_DBG_PRINT("cfg80211: Disabling "
                                        "channel %d MHz on %s due to "
                                        "Country IE\n",
                                        chan->center_freq, wiphy_name(wiphy));
                        flags |= IEEE80211_CHAN_DISABLED;
                        chan->flags = flags;
                }
                return;
        }

        power_rule = &reg_rule->power_rule;
        freq_range = &reg_rule->freq_range;

        if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(40))
                bw_flags = IEEE80211_CHAN_NO_HT40;

        if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER &&
            request_wiphy && request_wiphy == wiphy &&
            request_wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY) {
                /*
                 * This gaurantees the driver's requested regulatory domain
                 * will always be used as a base for further regulatory
                 * settings
                 */
                chan->flags = chan->orig_flags =
                        map_regdom_flags(reg_rule->flags) | bw_flags;
                chan->max_antenna_gain = chan->orig_mag =
                        (int) MBI_TO_DBI(power_rule->max_antenna_gain);
                chan->max_power = chan->orig_mpwr =
                        (int) MBM_TO_DBM(power_rule->max_eirp);
                return;
        }

        chan->flags = flags | bw_flags | map_regdom_flags(reg_rule->flags);
        chan->max_antenna_gain = min(chan->orig_mag,
                (int) MBI_TO_DBI(power_rule->max_antenna_gain));
        if (chan->orig_mpwr)
                chan->max_power = min(chan->orig_mpwr,
                        (int) MBM_TO_DBM(power_rule->max_eirp));
        else
                chan->max_power = (int) MBM_TO_DBM(power_rule->max_eirp);
}

static void handle_band(struct wiphy *wiphy, enum ieee80211_band band)
{
        unsigned int i;
        struct ieee80211_supported_band *sband;

        BUG_ON(!wiphy->bands[band]);
        sband = wiphy->bands[band];

        for (i = 0; i < sband->n_channels; i++)
                handle_channel(wiphy, band, i);
}

static bool ignore_reg_update(struct wiphy *wiphy,
                              enum nl80211_reg_initiator initiator)
{
        if (!last_request)
                return true;
        if (initiator == NL80211_REGDOM_SET_BY_CORE &&
            wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY)
                return true;
        /*
         * wiphy->regd will be set once the device has its own
         * desired regulatory domain set
         */
        if (wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY && !wiphy->regd &&
            !is_world_regdom(last_request->alpha2))
                return true;
        return false;
}

static void update_all_wiphy_regulatory(enum nl80211_reg_initiator initiator)
{
        struct cfg80211_registered_device *rdev;

        list_for_each_entry(rdev, &cfg80211_rdev_list, list)
                wiphy_update_regulatory(&rdev->wiphy, initiator);
}

static void handle_reg_beacon(struct wiphy *wiphy,
                              unsigned int chan_idx,
                              struct reg_beacon *reg_beacon)
{
        struct ieee80211_supported_band *sband;
        struct ieee80211_channel *chan;
        bool channel_changed = false;
        struct ieee80211_channel chan_before;

        assert_cfg80211_lock();

        sband = wiphy->bands[reg_beacon->chan.band];
        chan = &sband->channels[chan_idx];

        if (likely(chan->center_freq != reg_beacon->chan.center_freq))
                return;

        if (chan->beacon_found)
                return;

        chan->beacon_found = true;

        if (wiphy->flags & WIPHY_FLAG_DISABLE_BEACON_HINTS)
                return;

        chan_before.center_freq = chan->center_freq;
        chan_before.flags = chan->flags;

        if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) {
                chan->flags &= ~IEEE80211_CHAN_PASSIVE_SCAN;
                channel_changed = true;
        }

        if (chan->flags & IEEE80211_CHAN_NO_IBSS) {
                chan->flags &= ~IEEE80211_CHAN_NO_IBSS;
                channel_changed = true;
        }

        if (channel_changed)
                nl80211_send_beacon_hint_event(wiphy, &chan_before, chan);
}

/*
 * Called when a scan on a wiphy finds a beacon on
 * new channel
 */
static void wiphy_update_new_beacon(struct wiphy *wiphy,
                                    struct reg_beacon *reg_beacon)
{
        unsigned int i;
        struct ieee80211_supported_band *sband;

        assert_cfg80211_lock();

        if (!wiphy->bands[reg_beacon->chan.band])
                return;

        sband = wiphy->bands[reg_beacon->chan.band];

        for (i = 0; i < sband->n_channels; i++)
                handle_reg_beacon(wiphy, i, reg_beacon);
}

/*
 * Called upon reg changes or a new wiphy is added
 */
static void wiphy_update_beacon_reg(struct wiphy *wiphy)
{
        unsigned int i;
        struct ieee80211_supported_band *sband;
        struct reg_beacon *reg_beacon;

        assert_cfg80211_lock();

        if (list_empty(&reg_beacon_list))
                return;

        list_for_each_entry(reg_beacon, &reg_beacon_list, list) {
                if (!wiphy->bands[reg_beacon->chan.band])
                        continue;
                sband = wiphy->bands[reg_beacon->chan.band];
                for (i = 0; i < sband->n_channels; i++)
                        handle_reg_beacon(wiphy, i, reg_beacon);
        }
}

static bool reg_is_world_roaming(struct wiphy *wiphy)
{
        if (is_world_regdom(cfg80211_regdomain->alpha2) ||
            (wiphy->regd && is_world_regdom(wiphy->regd->alpha2)))
                return true;
        if (last_request &&
            last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&
            wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY)
                return true;
        return false;
}

/* Reap the advantages of previously found beacons */
static void reg_process_beacons(struct wiphy *wiphy)
{
        /*
         * Means we are just firing up cfg80211, so no beacons would
         * have been processed yet.
         */
        if (!last_request)
                return;
        if (!reg_is_world_roaming(wiphy))
                return;
        wiphy_update_beacon_reg(wiphy);
}

static bool is_ht40_not_allowed(struct ieee80211_channel *chan)
{
        if (!chan)
                return true;
        if (chan->flags & IEEE80211_CHAN_DISABLED)
                return true;
        /* This would happen when regulatory rules disallow HT40 completely */
        if (IEEE80211_CHAN_NO_HT40 == (chan->flags & (IEEE80211_CHAN_NO_HT40)))
                return true;
        return false;
}

static void reg_process_ht_flags_channel(struct wiphy *wiphy,
                                         enum ieee80211_band band,
                                         unsigned int chan_idx)
{
        struct ieee80211_supported_band *sband;
        struct ieee80211_channel *channel;
        struct ieee80211_channel *channel_before = NULL, *channel_after = NULL;
        unsigned int i;

        assert_cfg80211_lock();

        sband = wiphy->bands[band];
        BUG_ON(chan_idx >= sband->n_channels);
        channel = &sband->channels[chan_idx];

        if (is_ht40_not_allowed(channel)) {
                channel->flags |= IEEE80211_CHAN_NO_HT40;
                return;
        }

        /*
         * We need to ensure the extension channels exist to
         * be able to use HT40- or HT40+, this finds them (or not)
         */
        for (i = 0; i < sband->n_channels; i++) {
                struct ieee80211_channel *c = &sband->channels[i];
                if (c->center_freq == (channel->center_freq - 20))
                        channel_before = c;
                if (c->center_freq == (channel->center_freq + 20))
                        channel_after = c;
        }

        /*
         * Please note that this assumes target bandwidth is 20 MHz,
         * if that ever changes we also need to change the below logic
         * to include that as well.
         */
        if (is_ht40_not_allowed(channel_before))
                channel->flags |= IEEE80211_CHAN_NO_HT40MINUS;
        else
                channel->flags &= ~IEEE80211_CHAN_NO_HT40MINUS;

        if (is_ht40_not_allowed(channel_after))
                channel->flags |= IEEE80211_CHAN_NO_HT40PLUS;
        else
                channel->flags &= ~IEEE80211_CHAN_NO_HT40PLUS;
}

static void reg_process_ht_flags_band(struct wiphy *wiphy,
                                      enum ieee80211_band band)
{
        unsigned int i;
        struct ieee80211_supported_band *sband;

        BUG_ON(!wiphy->bands[band]);
        sband = wiphy->bands[band];

        for (i = 0; i < sband->n_channels; i++)
                reg_process_ht_flags_channel(wiphy, band, i);
}

static void reg_process_ht_flags(struct wiphy *wiphy)
{
        enum ieee80211_band band;

        if (!wiphy)
                return;

        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                if (wiphy->bands[band])
                        reg_process_ht_flags_band(wiphy, band);
        }

}

void wiphy_update_regulatory(struct wiphy *wiphy,
                             enum nl80211_reg_initiator initiator)
{
        enum ieee80211_band band;

        if (ignore_reg_update(wiphy, initiator))
                goto out;
        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                if (wiphy->bands[band])
                        handle_band(wiphy, band);
        }
out:
        reg_process_beacons(wiphy);
        reg_process_ht_flags(wiphy);
        if (wiphy->reg_notifier)
                wiphy->reg_notifier(wiphy, last_request);
}

static void handle_channel_custom(struct wiphy *wiphy,
                                  enum ieee80211_band band,
                                  unsigned int chan_idx,
                                  const struct ieee80211_regdomain *regd)
{
        int r;
        u32 desired_bw_khz = MHZ_TO_KHZ(20);
        u32 bw_flags = 0;
        const struct ieee80211_reg_rule *reg_rule = NULL;
        const struct ieee80211_power_rule *power_rule = NULL;
        const struct ieee80211_freq_range *freq_range = NULL;
        struct ieee80211_supported_band *sband;
        struct ieee80211_channel *chan;

        assert_reg_lock();

        sband = wiphy->bands[band];
        BUG_ON(chan_idx >= sband->n_channels);
        chan = &sband->channels[chan_idx];

        r = freq_reg_info_regd(wiphy,
                               MHZ_TO_KHZ(chan->center_freq),
                               desired_bw_khz,
                               &reg_rule,
                               regd);

        if (r) {
                chan->flags = IEEE80211_CHAN_DISABLED;
                return;
        }

        power_rule = &reg_rule->power_rule;
        freq_range = &reg_rule->freq_range;

        if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(40))
                bw_flags = IEEE80211_CHAN_NO_HT40;

        chan->flags |= map_regdom_flags(reg_rule->flags) | bw_flags;
        chan->max_antenna_gain = (int) MBI_TO_DBI(power_rule->max_antenna_gain);
        chan->max_power = (int) MBM_TO_DBM(power_rule->max_eirp);
}

static void handle_band_custom(struct wiphy *wiphy, enum ieee80211_band band,
                               const struct ieee80211_regdomain *regd)
{
        unsigned int i;
        struct ieee80211_supported_band *sband;

        BUG_ON(!wiphy->bands[band]);
        sband = wiphy->bands[band];

        for (i = 0; i < sband->n_channels; i++)
                handle_channel_custom(wiphy, band, i, regd);
}

/* Used by drivers prior to wiphy registration */
void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
                                   const struct ieee80211_regdomain *regd)
{
        enum ieee80211_band band;
        unsigned int bands_set = 0;

        mutex_lock(&reg_mutex);
        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                if (!wiphy->bands[band])
                        continue;
                handle_band_custom(wiphy, band, regd);
                bands_set++;
        }
        mutex_unlock(&reg_mutex);

        /*
         * no point in calling this if it won't have any effect
         * on your device's supportd bands.
         */
        WARN_ON(!bands_set);
}
EXPORT_SYMBOL(wiphy_apply_custom_regulatory);

/*
 * Return value which can be used by ignore_request() to indicate
 * it has been determined we should intersect two regulatory domains
 */
#define REG_INTERSECT   1

/* This has the logic which determines when a new request
 * should be ignored. */
static int ignore_request(struct wiphy *wiphy,
                          struct regulatory_request *pending_request)
{
        struct wiphy *last_wiphy = NULL;

        assert_cfg80211_lock();

        /* All initial requests are respected */
        if (!last_request)
                return 0;

        switch (pending_request->initiator) {
        case NL80211_REGDOM_SET_BY_CORE:
                return 0;
        case NL80211_REGDOM_SET_BY_COUNTRY_IE:

                last_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx);

                if (unlikely(!is_an_alpha2(pending_request->alpha2)))
                        return -EINVAL;
                if (last_request->initiator ==
                    NL80211_REGDOM_SET_BY_COUNTRY_IE) {
                        if (last_wiphy != wiphy) {
                                /*
                                 * Two cards with two APs claiming different
                                 * Country IE alpha2s. We could
                                 * intersect them, but that seems unlikely
                                 * to be correct. Reject second one for now.
                                 */
                                if (regdom_changes(pending_request->alpha2))
                                        return -EOPNOTSUPP;
                                return -EALREADY;
                        }
                        /*
                         * Two consecutive Country IE hints on the same wiphy.
                         * This should be picked up early by the driver/stack
                         */
                        if (WARN_ON(regdom_changes(pending_request->alpha2)))
                                return 0;
                        return -EALREADY;
                }
                return REG_INTERSECT;
        case NL80211_REGDOM_SET_BY_DRIVER:
                if (last_request->initiator == NL80211_REGDOM_SET_BY_CORE) {
                        if (regdom_changes(pending_request->alpha2))
                                return 0;
                        return -EALREADY;
                }

                /*
                 * This would happen if you unplug and plug your card
                 * back in or if you add a new device for which the previously
                 * loaded card also agrees on the regulatory domain.
                 */
                if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER &&
                    !regdom_changes(pending_request->alpha2))
                        return -EALREADY;

                return REG_INTERSECT;
        case NL80211_REGDOM_SET_BY_USER:
                if (last_request->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE)
                        return REG_INTERSECT;
                /*
                 * If the user knows better the user should set the regdom
                 * to their country before the IE is picked up
                 */
                if (last_request->initiator == NL80211_REGDOM_SET_BY_USER &&
                          last_request->intersect)
                        return -EOPNOTSUPP;
                /*
                 * Process user requests only after previous user/driver/core
                 * requests have been processed
                 */
                if (last_request->initiator == NL80211_REGDOM_SET_BY_CORE ||
                    last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER ||
                    last_request->initiator == NL80211_REGDOM_SET_BY_USER) {
                        if (regdom_changes(last_request->alpha2))
                                return -EAGAIN;
                }

                if (!regdom_changes(pending_request->alpha2))
                        return -EALREADY;

                return 0;
        }

        return -EINVAL;
}

/**
 * __regulatory_hint - hint to the wireless core a regulatory domain
 * @wiphy: if the hint comes from country information from an AP, this
 *      is required to be set to the wiphy that received the information
 * @pending_request: the regulatory request currently being processed
 *
 * The Wireless subsystem can use this function to hint to the wireless core
 * what it believes should be the current regulatory domain.
 *
 * Returns zero if all went fine, %-EALREADY if a regulatory domain had
 * already been set or other standard error codes.
 *
 * Caller must hold &cfg80211_mutex and &reg_mutex
 */
static int __regulatory_hint(struct wiphy *wiphy,
                             struct regulatory_request *pending_request)
{
        bool intersect = false;
        int r = 0;

        assert_cfg80211_lock();

        r = ignore_request(wiphy, pending_request);

        if (r == REG_INTERSECT) {
                if (pending_request->initiator ==
                    NL80211_REGDOM_SET_BY_DRIVER) {
                        r = reg_copy_regd(&wiphy->regd, cfg80211_regdomain);
                        if (r) {
                                kfree(pending_request);
                                return r;
                        }
                }
                intersect = true;
        } else if (r) {
                /*
                 * If the regulatory domain being requested by the
                 * driver has already been set just copy it to the
                 * wiphy
                 */
                if (r == -EALREADY &&
                    pending_request->initiator ==
                    NL80211_REGDOM_SET_BY_DRIVER) {
                        r = reg_copy_regd(&wiphy->regd, cfg80211_regdomain);
                        if (r) {
                                kfree(pending_request);
                                return r;
                        }
                        r = -EALREADY;
                        goto new_request;
                }
                kfree(pending_request);
                return r;
        }

new_request:
        kfree(last_request);

        last_request = pending_request;
        last_request->intersect = intersect;

        pending_request = NULL;

        if (last_request->initiator == NL80211_REGDOM_SET_BY_USER) {
                user_alpha2[0] = last_request->alpha2[0];
                user_alpha2[1] = last_request->alpha2[1];
        }

        /* When r == REG_INTERSECT we do need to call CRDA */
        if (r < 0) {
                /*
                 * Since CRDA will not be called in this case as we already
                 * have applied the requested regulatory domain before we just
                 * inform userspace we have processed the request
                 */
                if (r == -EALREADY)
                        nl80211_send_reg_change_event(last_request);
                return r;
        }

        return call_crda(last_request->alpha2);
}

/* This processes *all* regulatory hints */
static void reg_process_hint(struct regulatory_request *reg_request)
{
        int r = 0;
        struct wiphy *wiphy = NULL;

        BUG_ON(!reg_request->alpha2);

        mutex_lock(&cfg80211_mutex);
        mutex_lock(&reg_mutex);

        if (wiphy_idx_valid(reg_request->wiphy_idx))
                wiphy = wiphy_idx_to_wiphy(reg_request->wiphy_idx);

        if (reg_request->initiator == NL80211_REGDOM_SET_BY_DRIVER &&
            !wiphy) {
                kfree(reg_request);
                goto out;
        }

        r = __regulatory_hint(wiphy, reg_request);
        /* This is required so that the orig_* parameters are saved */
        if (r == -EALREADY && wiphy &&
            wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY)
                wiphy_update_regulatory(wiphy, reg_request->initiator);
out:
        mutex_unlock(&reg_mutex);
        mutex_unlock(&cfg80211_mutex);
}

/* Processes regulatory hints, this is all the NL80211_REGDOM_SET_BY_* */
static void reg_process_pending_hints(void)
        {
        struct regulatory_request *reg_request;

        spin_lock(&reg_requests_lock);
        while (!list_empty(&reg_requests_list)) {
                reg_request = list_first_entry(&reg_requests_list,
                                               struct regulatory_request,
                                               list);
                list_del_init(&reg_request->list);

                spin_unlock(&reg_requests_lock);
                reg_process_hint(reg_request);
                spin_lock(&reg_requests_lock);
        }
        spin_unlock(&reg_requests_lock);
}

/* Processes beacon hints -- this has nothing to do with country IEs */
static void reg_process_pending_beacon_hints(void)
{
        struct cfg80211_registered_device *rdev;
        struct reg_beacon *pending_beacon, *tmp;

        /*
         * No need to hold the reg_mutex here as we just touch wiphys
         * and do not read or access regulatory variables.
         */
        mutex_lock(&cfg80211_mutex);

        /* This goes through the _pending_ beacon list */
        spin_lock_bh(&reg_pending_beacons_lock);

        if (list_empty(&reg_pending_beacons)) {
                spin_unlock_bh(&reg_pending_beacons_lock);
                goto out;
        }

        list_for_each_entry_safe(pending_beacon, tmp,
                                 &reg_pending_beacons, list) {

                list_del_init(&pending_beacon->list);

                /* Applies the beacon hint to current wiphys */
                list_for_each_entry(rdev, &cfg80211_rdev_list, list)
                        wiphy_update_new_beacon(&rdev->wiphy, pending_beacon);

                /* Remembers the beacon hint for new wiphys or reg changes */
                list_add_tail(&pending_beacon->list, &reg_beacon_list);
        }

        spin_unlock_bh(&reg_pending_beacons_lock);
out:
        mutex_unlock(&cfg80211_mutex);
}

static void reg_todo(struct work_struct *work)
{
        reg_process_pending_hints();
        reg_process_pending_beacon_hints();
}

static DECLARE_WORK(reg_work, reg_todo);

static void queue_regulatory_request(struct regulatory_request *request)
{
        spin_lock(&reg_requests_lock);
        list_add_tail(&request->list, &reg_requests_list);
        spin_unlock(&reg_requests_lock);

        schedule_work(&reg_work);
}

/*
 * Core regulatory hint -- happens during cfg80211_init()
 * and when we restore regulatory settings.
 */
static int regulatory_hint_core(const char *alpha2)
{
        struct regulatory_request *request;

        kfree(last_request);
        last_request = NULL;

        request = kzalloc(sizeof(struct regulatory_request),
                          GFP_KERNEL);
        if (!request)
                return -ENOMEM;

        request->alpha2[0] = alpha2[0];
        request->alpha2[1] = alpha2[1];
        request->initiator = NL80211_REGDOM_SET_BY_CORE;

        /*
         * This ensures last_request is populated once modules
         * come swinging in and calling regulatory hints and
         * wiphy_apply_custom_regulatory().
         */
        reg_process_hint(request);

        return 0;
}

/* User hints */
int regulatory_hint_user(const char *alpha2)
{
        struct regulatory_request *request;

        BUG_ON(!alpha2);

        request = kzalloc(sizeof(struct regulatory_request), GFP_KERNEL);
        if (!request)
                return -ENOMEM;

        request->wiphy_idx = WIPHY_IDX_STALE;
        request->alpha2[0] = alpha2[0];
        request->alpha2[1] = alpha2[1];
        request->initiator = NL80211_REGDOM_SET_BY_USER;

        queue_regulatory_request(request);

        return 0;
}

/* Driver hints */
int regulatory_hint(struct wiphy *wiphy, const char *alpha2)
{
        struct regulatory_request *request;

        BUG_ON(!alpha2);
        BUG_ON(!wiphy);

        request = kzalloc(sizeof(struct regulatory_request), GFP_KERNEL);
        if (!request)
                return -ENOMEM;

        request->wiphy_idx = get_wiphy_idx(wiphy);

        /* Must have registered wiphy first */
        BUG_ON(!wiphy_idx_valid(request->wiphy_idx));

        request->alpha2[0] = alpha2[0];
        request->alpha2[1] = alpha2[1];
        request->initiator = NL80211_REGDOM_SET_BY_DRIVER;

        queue_regulatory_request(request);

        return 0;
}
EXPORT_SYMBOL(regulatory_hint);

/* Caller must hold reg_mutex */
static bool reg_same_country_ie_hint(struct wiphy *wiphy,
                        u32 country_ie_checksum)
{
        struct wiphy *request_wiphy;

        assert_reg_lock();

        if (unlikely(last_request->initiator !=
            NL80211_REGDOM_SET_BY_COUNTRY_IE))
                return false;

        request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx);

        if (!request_wiphy)
                return false;

        if (likely(request_wiphy != wiphy))
                return !country_ie_integrity_changes(country_ie_checksum);
        /*
         * We should not have let these through at this point, they
         * should have been picked up earlier by the first alpha2 check
         * on the device
         */
        if (WARN_ON(!country_ie_integrity_changes(country_ie_checksum)))
                return true;
        return false;
}

/*
 * We hold wdev_lock() here so we cannot hold cfg80211_mutex() and
 * therefore cannot iterate over the rdev list here.
 */
void regulatory_hint_11d(struct wiphy *wiphy,
                         enum ieee80211_band band,
                         u8 *country_ie,
                         u8 country_ie_len)
{
        struct ieee80211_regdomain *rd = NULL;
        char alpha2[2];
        u32 checksum = 0;
        enum environment_cap env = ENVIRON_ANY;
        struct regulatory_request *request;

        mutex_lock(&reg_mutex);

        if (unlikely(!last_request))
                goto out;

        /* IE len must be evenly divisible by 2 */
        if (country_ie_len & 0x01)
                goto out;

        if (country_ie_len < IEEE80211_COUNTRY_IE_MIN_LEN)
                goto out;

        /*
         * Pending country IE processing, this can happen after we
         * call CRDA and wait for a response if a beacon was received before
         * we were able to process the last regulatory_hint_11d() call
         */
        if (country_ie_regdomain)
                goto out;

        alpha2[0] = country_ie[0];
        alpha2[1] = country_ie[1];

        if (country_ie[2] == 'I')
                env = ENVIRON_INDOOR;
        else if (country_ie[2] == 'O')
                env = ENVIRON_OUTDOOR;

        /*
         * We will run this only upon a successful connection on cfg80211.
         * We leave conflict resolution to the workqueue, where can hold
         * cfg80211_mutex.
         */
        if (likely(last_request->initiator ==
            NL80211_REGDOM_SET_BY_COUNTRY_IE &&
            wiphy_idx_valid(last_request->wiphy_idx)))
                goto out;

        rd = country_ie_2_rd(band, country_ie, country_ie_len, &checksum);
        if (!rd) {
                REG_DBG_PRINT("cfg80211: Ignoring bogus country IE\n");
                goto out;
        }

        /*
         * This will not happen right now but we leave it here for the
         * the future when we want to add suspend/resume support and having
         * the user move to another country after doing so, or having the user
         * move to another AP. Right now we just trust the first AP.
         *
         * If we hit this before we add this support we want to be informed of
         * it as it would indicate a mistake in the current design
         */
        if (WARN_ON(reg_same_country_ie_hint(wiphy, checksum)))
                goto free_rd_out;

        request = kzalloc(sizeof(struct regulatory_request), GFP_KERNEL);
        if (!request)
                goto free_rd_out;

        /*
         * We keep this around for when CRDA comes back with a response so
         * we can intersect with that
         */
        country_ie_regdomain = rd;

        request->wiphy_idx = get_wiphy_idx(wiphy);
        request->alpha2[0] = rd->alpha2[0];
        request->alpha2[1] = rd->alpha2[1];
        request->initiator = NL80211_REGDOM_SET_BY_COUNTRY_IE;
        request->country_ie_checksum = checksum;
        request->country_ie_env = env;

        mutex_unlock(&reg_mutex);

        queue_regulatory_request(request);

        return;

free_rd_out:
        kfree(rd);
out:
        mutex_unlock(&reg_mutex);
}

static void restore_alpha2(char *alpha2, bool reset_user)
{
        /* indicates there is no alpha2 to consider for restoration */
        alpha2[0] = '9';
        alpha2[1] = '7';

        /* The user setting has precedence over the module parameter */
        if (is_user_regdom_saved()) {
                /* Unless we're asked to ignore it and reset it */
                if (reset_user) {
                        REG_DBG_PRINT("cfg80211: Restoring regulatory settings "
                               "including user preference\n");
                        user_alpha2[0] = '9';
                        user_alpha2[1] = '7';

                        /*
                         * If we're ignoring user settings, we still need to
                         * check the module parameter to ensure we put things
                         * back as they were for a full restore.
                         */
                        if (!is_world_regdom(ieee80211_regdom)) {
                                REG_DBG_PRINT("cfg80211: Keeping preference on "
                                       "module parameter ieee80211_regdom: %c%c\n",
                                       ieee80211_regdom[0],
                                       ieee80211_regdom[1]);
                                alpha2[0] = ieee80211_regdom[0];
                                alpha2[1] = ieee80211_regdom[1];
                        }
                } else {
                        REG_DBG_PRINT("cfg80211: Restoring regulatory settings "
                               "while preserving user preference for: %c%c\n",
                               user_alpha2[0],
                               user_alpha2[1]);
                        alpha2[0] = user_alpha2[0];
                        alpha2[1] = user_alpha2[1];
                }
        } else if (!is_world_regdom(ieee80211_regdom)) {
                REG_DBG_PRINT("cfg80211: Keeping preference on "
                       "module parameter ieee80211_regdom: %c%c\n",
                       ieee80211_regdom[0],
                       ieee80211_regdom[1]);
                alpha2[0] = ieee80211_regdom[0];
                alpha2[1] = ieee80211_regdom[1];
        } else
                REG_DBG_PRINT("cfg80211: Restoring regulatory settings\n");
}

/*
 * Restoring regulatory settings involves ingoring any
 * possibly stale country IE information and user regulatory
 * settings if so desired, this includes any beacon hints
 * learned as we could have traveled outside to another country
 * after disconnection. To restore regulatory settings we do
 * exactly what we did at bootup:
 *
 *   - send a core regulatory hint
 *   - send a user regulatory hint if applicable
 *
 * Device drivers that send a regulatory hint for a specific country
 * keep their own regulatory domain on wiphy->regd so that does does
 * not need to be remembered.
 */
static void restore_regulatory_settings(bool reset_user)
{
        char alpha2[2];
        struct reg_beacon *reg_beacon, *btmp;

        mutex_lock(&cfg80211_mutex);
        mutex_lock(&reg_mutex);

        reset_regdomains();
        restore_alpha2(alpha2, reset_user);

        /* Clear beacon hints */
        spin_lock_bh(&reg_pending_beacons_lock);
        if (!list_empty(&reg_pending_beacons)) {
                list_for_each_entry_safe(reg_beacon, btmp,
                                         &reg_pending_beacons, list) {
                        list_del(&reg_beacon->list);
                        kfree(reg_beacon);
                }
        }
        spin_unlock_bh(&reg_pending_beacons_lock);

        if (!list_empty(&reg_beacon_list)) {
                list_for_each_entry_safe(reg_beacon, btmp,
                                         &reg_beacon_list, list) {
                        list_del(&reg_beacon->list);
                        kfree(reg_beacon);
                }
        }

        /* First restore to the basic regulatory settings */
        cfg80211_regdomain = cfg80211_world_regdom;

        mutex_unlock(&reg_mutex);
        mutex_unlock(&cfg80211_mutex);

        regulatory_hint_core(cfg80211_regdomain->alpha2);

        /*
         * This restores the ieee80211_regdom module parameter
         * preference or the last user requested regulatory
         * settings, user regulatory settings takes precedence.
         */
        if (is_an_alpha2(alpha2))
                regulatory_hint_user(user_alpha2);
}


void regulatory_hint_disconnect(void)
{
        REG_DBG_PRINT("cfg80211: All devices are disconnected, going to "
                      "restore regulatory settings\n");
        restore_regulatory_settings(false);
}

static bool freq_is_chan_12_13_14(u16 freq)
{
        if (freq == ieee80211_channel_to_frequency(12) ||
            freq == ieee80211_channel_to_frequency(13) ||
            freq == ieee80211_channel_to_frequency(14))
                return true;
        return false;
}

int regulatory_hint_found_beacon(struct wiphy *wiphy,
                                 struct ieee80211_channel *beacon_chan,
                                 gfp_t gfp)
{
        struct reg_beacon *reg_beacon;

        if (likely((beacon_chan->beacon_found ||
            (beacon_chan->flags & IEEE80211_CHAN_RADAR) ||
            (beacon_chan->band == IEEE80211_BAND_2GHZ &&
             !freq_is_chan_12_13_14(beacon_chan->center_freq)))))
                return 0;

        reg_beacon = kzalloc(sizeof(struct reg_beacon), gfp);
        if (!reg_beacon)
                return -ENOMEM;

        REG_DBG_PRINT("cfg80211: Found new beacon on "
                      "frequency: %d MHz (Ch %d) on %s\n",
                      beacon_chan->center_freq,
                      ieee80211_frequency_to_channel(beacon_chan->center_freq),
                      wiphy_name(wiphy));

        memcpy(&reg_beacon->chan, beacon_chan,
                sizeof(struct ieee80211_channel));


        /*
         * Since we can be called from BH or and non-BH context
         * we must use spin_lock_bh()
         */
        spin_lock_bh(&reg_pending_beacons_lock);
        list_add_tail(&reg_beacon->list, &reg_pending_beacons);
        spin_unlock_bh(&reg_pending_beacons_lock);

        schedule_work(&reg_work);

        return 0;
}

static void print_rd_rules(const struct ieee80211_regdomain *rd)
{
        unsigned int i;
        const struct ieee80211_reg_rule *reg_rule = NULL;
        const struct ieee80211_freq_range *freq_range = NULL;
        const struct ieee80211_power_rule *power_rule = NULL;

        printk(KERN_INFO "    (start_freq - end_freq @ bandwidth), "
                "(max_antenna_gain, max_eirp)\n");

        for (i = 0; i < rd->n_reg_rules; i++) {
                reg_rule = &rd->reg_rules[i];
                freq_range = &reg_rule->freq_range;
                power_rule = &reg_rule->power_rule;

                /*
                 * There may not be documentation for max antenna gain
                 * in certain regions
                 */
                if (power_rule->max_antenna_gain)
                        printk(KERN_INFO "    (%d KHz - %d KHz @ %d KHz), "
                                "(%d mBi, %d mBm)\n",
                                freq_range->start_freq_khz,
                                freq_range->end_freq_khz,
                                freq_range->max_bandwidth_khz,
                                power_rule->max_antenna_gain,
                                power_rule->max_eirp);
                else
                        printk(KERN_INFO "    (%d KHz - %d KHz @ %d KHz), "
                                "(N/A, %d mBm)\n",
                                freq_range->start_freq_khz,
                                freq_range->end_freq_khz,
                                freq_range->max_bandwidth_khz,
                                power_rule->max_eirp);
        }
}

static void print_regdomain(const struct ieee80211_regdomain *rd)
{

        if (is_intersected_alpha2(rd->alpha2)) {

                if (last_request->initiator ==
                    NL80211_REGDOM_SET_BY_COUNTRY_IE) {
                        struct cfg80211_registered_device *rdev;
                        rdev = cfg80211_rdev_by_wiphy_idx(
                                last_request->wiphy_idx);
                        if (rdev) {
                                printk(KERN_INFO "cfg80211: Current regulatory "
                                        "domain updated by AP to: %c%c\n",
                                        rdev->country_ie_alpha2[0],
                                        rdev->country_ie_alpha2[1]);
                        } else
                                printk(KERN_INFO "cfg80211: Current regulatory "
                                        "domain intersected: \n");
                } else
                                printk(KERN_INFO "cfg80211: Current regulatory "
                                        "domain intersected: \n");
        } else if (is_world_regdom(rd->alpha2))
                printk(KERN_INFO "cfg80211: World regulatory "
                        "domain updated:\n");
        else {
                if (is_unknown_alpha2(rd->alpha2))
                        printk(KERN_INFO "cfg80211: Regulatory domain "
                                "changed to driver built-in settings "
                                "(unknown country)\n");
                else
                        printk(KERN_INFO "cfg80211: Regulatory domain "
                                "changed to country: %c%c\n",
                                rd->alpha2[0], rd->alpha2[1]);
        }
        print_rd_rules(rd);
}

static void print_regdomain_info(const struct ieee80211_regdomain *rd)
{
        printk(KERN_INFO "cfg80211: Regulatory domain: %c%c\n",
                rd->alpha2[0], rd->alpha2[1]);
        print_rd_rules(rd);
}

#ifdef CONFIG_CFG80211_REG_DEBUG
static void reg_country_ie_process_debug(
        const struct ieee80211_regdomain *rd,
        const struct ieee80211_regdomain *country_ie_regdomain,
        const struct ieee80211_regdomain *intersected_rd)
{
        printk(KERN_DEBUG "cfg80211: Received country IE:\n");
        print_regdomain_info(country_ie_regdomain);
        printk(KERN_DEBUG "cfg80211: CRDA thinks this should applied:\n");
        print_regdomain_info(rd);
        if (intersected_rd) {
                printk(KERN_DEBUG "cfg80211: We intersect both of these "
                        "and get:\n");
                print_regdomain_info(intersected_rd);
                return;
        }
        printk(KERN_DEBUG "cfg80211: Intersection between both failed\n");
}
#else
static inline void reg_country_ie_process_debug(
        const struct ieee80211_regdomain *rd,
        const struct ieee80211_regdomain *country_ie_regdomain,
        const struct ieee80211_regdomain *intersected_rd)
{
}
#endif

/* Takes ownership of rd only if it doesn't fail */
static int __set_regdom(const struct ieee80211_regdomain *rd)
{
        const struct ieee80211_regdomain *intersected_rd = NULL;
        struct cfg80211_registered_device *rdev = NULL;
        struct wiphy *request_wiphy;
        /* Some basic sanity checks first */

        if (is_world_regdom(rd->alpha2)) {
                if (WARN_ON(!reg_is_valid_request(rd->alpha2)))
                        return -EINVAL;
                update_world_regdomain(rd);
                return 0;
        }

        if (!is_alpha2_set(rd->alpha2) && !is_an_alpha2(rd->alpha2) &&
                        !is_unknown_alpha2(rd->alpha2))
                return -EINVAL;

        if (!last_request)
                return -EINVAL;

        /*
         * Lets only bother proceeding on the same alpha2 if the current
         * rd is non static (it means CRDA was present and was used last)
         * and the pending request came in from a country IE
         */
        if (last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE) {
                /*
                 * If someone else asked us to change the rd lets only bother
                 * checking if the alpha2 changes if CRDA was already called
                 */
                if (!regdom_changes(rd->alpha2))
                        return -EINVAL;
        }

        /*
         * Now lets set the regulatory domain, update all driver channels
         * and finally inform them of what we have done, in case they want
         * to review or adjust their own settings based on their own
         * internal EEPROM data
         */

        if (WARN_ON(!reg_is_valid_request(rd->alpha2)))
                return -EINVAL;

        if (!is_valid_rd(rd)) {
                printk(KERN_ERR "cfg80211: Invalid "
                        "regulatory domain detected:\n");
                print_regdomain_info(rd);
                return -EINVAL;
        }

        request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx);

        if (!last_request->intersect) {
                int r;

                if (last_request->initiator != NL80211_REGDOM_SET_BY_DRIVER) {
                        reset_regdomains();
                        cfg80211_regdomain = rd;
                        return 0;
                }

                /*
                 * For a driver hint, lets copy the regulatory domain the
                 * driver wanted to the wiphy to deal with conflicts
                 */

                /*
                 * Userspace could have sent two replies with only
                 * one kernel request.
                 */
                if (request_wiphy->regd)
                        return -EALREADY;

                r = reg_copy_regd(&request_wiphy->regd, rd);
                if (r)
                        return r;

                reset_regdomains();
                cfg80211_regdomain = rd;
                return 0;
        }

        /* Intersection requires a bit more work */

        if (last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE) {

                intersected_rd = regdom_intersect(rd, cfg80211_regdomain);
                if (!intersected_rd)
                        return -EINVAL;

                /*
                 * We can trash what CRDA provided now.
                 * However if a driver requested this specific regulatory
                 * domain we keep it for its private use
                 */
                if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER)
                        request_wiphy->regd = rd;
                else
                        kfree(rd);

                rd = NULL;

                reset_regdomains();
                cfg80211_regdomain = intersected_rd;

                return 0;
        }

        /*
         * Country IE requests are handled a bit differently, we intersect
         * the country IE rd with what CRDA believes that country should have
         */

        /*
         * Userspace could have sent two replies with only
         * one kernel request. By the second reply we would have
         * already processed and consumed the country_ie_regdomain.
         */
        if (!country_ie_regdomain)
                return -EALREADY;
        BUG_ON(rd == country_ie_regdomain);

        /*
         * Intersect what CRDA returned and our what we
         * had built from the Country IE received
         */

        intersected_rd = regdom_intersect(rd, country_ie_regdomain);

        reg_country_ie_process_debug(rd,
                                     country_ie_regdomain,
                                     intersected_rd);

        kfree(country_ie_regdomain);
        country_ie_regdomain = NULL;

        if (!intersected_rd)
                return -EINVAL;

        rdev = wiphy_to_dev(request_wiphy);

        rdev->country_ie_alpha2[0] = rd->alpha2[0];
        rdev->country_ie_alpha2[1] = rd->alpha2[1];
        rdev->env = last_request->country_ie_env;

        BUG_ON(intersected_rd == rd);

        kfree(rd);
        rd = NULL;

        reset_regdomains();
        cfg80211_regdomain = intersected_rd;

        return 0;
}


/*
 * Use this call to set the current regulatory domain. Conflicts with
 * multiple drivers can be ironed out later. Caller must've already
 * kmalloc'd the rd structure. Caller must hold cfg80211_mutex
 */
int set_regdom(const struct ieee80211_regdomain *rd)
{
        int r;

        assert_cfg80211_lock();

        mutex_lock(&reg_mutex);

        /* Note that this doesn't update the wiphys, this is done below */
        r = __set_regdom(rd);
        if (r) {
                kfree(rd);
                mutex_unlock(&reg_mutex);
                return r;
        }

        /* This would make this whole thing pointless */
        if (!last_request->intersect)
                BUG_ON(rd != cfg80211_regdomain);

        /* update all wiphys now with the new established regulatory domain */
        update_all_wiphy_regulatory(last_request->initiator);

        print_regdomain(cfg80211_regdomain);

        nl80211_send_reg_change_event(last_request);

        mutex_unlock(&reg_mutex);

        return r;
}

/* Caller must hold cfg80211_mutex */
void reg_device_remove(struct wiphy *wiphy)
{
        struct wiphy *request_wiphy = NULL;

        assert_cfg80211_lock();

        mutex_lock(&reg_mutex);

        kfree(wiphy->regd);

        if (last_request)
                request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx);

        if (!request_wiphy || request_wiphy != wiphy)
                goto out;

        last_request->wiphy_idx = WIPHY_IDX_STALE;
        last_request->country_ie_env = ENVIRON_ANY;
out:
        mutex_unlock(&reg_mutex);
}

int regulatory_init(void)
{
        int err = 0;

        reg_pdev = platform_device_register_simple("regulatory", 0, NULL, 0);
        if (IS_ERR(reg_pdev))
                return PTR_ERR(reg_pdev);

        spin_lock_init(&reg_requests_lock);
        spin_lock_init(&reg_pending_beacons_lock);

        cfg80211_regdomain = cfg80211_world_regdom;

        user_alpha2[0] = '9';
        user_alpha2[1] = '7';

        /* We always try to get an update for the static regdomain */
        err = regulatory_hint_core(cfg80211_regdomain->alpha2);
        if (err) {
                if (err == -ENOMEM)
                        return err;
                /*
                 * N.B. kobject_uevent_env() can fail mainly for when we're out
                 * memory which is handled and propagated appropriately above
                 * but it can also fail during a netlink_broadcast() or during
                 * early boot for call_usermodehelper(). For now treat these
                 * errors as non-fatal.
                 */
                printk(KERN_ERR "cfg80211: kobject_uevent_env() was unable "
                        "to call CRDA during init");
#ifdef CONFIG_CFG80211_REG_DEBUG
                /* We want to find out exactly why when debugging */
                WARN_ON(err);
#endif
        }

        /*
         * Finally, if the user set the module parameter treat it
         * as a user hint.
         */
        if (!is_world_regdom(ieee80211_regdom))
                regulatory_hint_user(ieee80211_regdom);

        return 0;
}

void regulatory_exit(void)
{
        struct regulatory_request *reg_request, *tmp;
        struct reg_beacon *reg_beacon, *btmp;

        cancel_work_sync(&reg_work);

        mutex_lock(&cfg80211_mutex);
        mutex_lock(&reg_mutex);

        reset_regdomains();

        kfree(country_ie_regdomain);
        country_ie_regdomain = NULL;

        kfree(last_request);

        platform_device_unregister(reg_pdev);

        spin_lock_bh(&reg_pending_beacons_lock);
        if (!list_empty(&reg_pending_beacons)) {
                list_for_each_entry_safe(reg_beacon, btmp,
                                         &reg_pending_beacons, list) {
                        list_del(&reg_beacon->list);
                        kfree(reg_beacon);
                }
        }
        spin_unlock_bh(&reg_pending_beacons_lock);

        if (!list_empty(&reg_beacon_list)) {
                list_for_each_entry_safe(reg_beacon, btmp,
                                         &reg_beacon_list, list) {
                        list_del(&reg_beacon->list);
                        kfree(reg_beacon);
                }
        }

        spin_lock(&reg_requests_lock);
        if (!list_empty(&reg_requests_list)) {
                list_for_each_entry_safe(reg_request, tmp,
                                         &reg_requests_list, list) {
                        list_del(&reg_request->list);
                        kfree(reg_request);
                }
        }
        spin_unlock(&reg_requests_lock);

        mutex_unlock(&reg_mutex);
        mutex_unlock(&cfg80211_mutex);
}