nilfs2: fix preempt count underflow in nilfs_btnode_prepare_change_key

[linux-2.6/mini2440.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/list.h>
#include <linux/random.h>
#include <linux/nl80211.h>
#include <linux/platform_device.h>
#include <net/wireless.h>
#include <net/cfg80211.h>
#include "core.h"
#include "reg.h"
#include "nl80211.h"

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

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

/* Keep the ordering from large to small */
static u32 supported_bandwidths[] = {
        MHZ_TO_KHZ(40),
        MHZ_TO_KHZ(20),
};

/*
 * 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;

/* 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;

#ifdef CONFIG_WIRELESS_OLD_REGULATORY
static char *ieee80211_regdom = "US";
#else
static char *ieee80211_regdom = "00";
#endif

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

#ifdef CONFIG_WIRELESS_OLD_REGULATORY
/*
 * We assume 40 MHz bandwidth for the old regulatory work.
 * We make emphasis we are using the exact same frequencies
 * as before
 */

static const struct ieee80211_regdomain us_regdom = {
        .n_reg_rules = 6,
        .alpha2 =  "US",
        .reg_rules = {
                /* IEEE 802.11b/g, channels 1..11 */
                REG_RULE(2412-10, 2462+10, 40, 6, 27, 0),
                /* IEEE 802.11a, channel 36 */
                REG_RULE(5180-10, 5180+10, 40, 6, 23, 0),
                /* IEEE 802.11a, channel 40 */
                REG_RULE(5200-10, 5200+10, 40, 6, 23, 0),
                /* IEEE 802.11a, channel 44 */
                REG_RULE(5220-10, 5220+10, 40, 6, 23, 0),
                /* IEEE 802.11a, channels 48..64 */
                REG_RULE(5240-10, 5320+10, 40, 6, 23, 0),
                /* IEEE 802.11a, channels 149..165, outdoor */
                REG_RULE(5745-10, 5825+10, 40, 6, 30, 0),
        }
};

static const struct ieee80211_regdomain jp_regdom = {
        .n_reg_rules = 3,
        .alpha2 =  "JP",
        .reg_rules = {
                /* IEEE 802.11b/g, channels 1..14 */
                REG_RULE(2412-10, 2484+10, 40, 6, 20, 0),
                /* IEEE 802.11a, channels 34..48 */
                REG_RULE(5170-10, 5240+10, 40, 6, 20,
                        NL80211_RRF_PASSIVE_SCAN),
                /* IEEE 802.11a, channels 52..64 */
                REG_RULE(5260-10, 5320+10, 40, 6, 20,
                        NL80211_RRF_NO_IBSS |
                        NL80211_RRF_DFS),
        }
};

static const struct ieee80211_regdomain eu_regdom = {
        .n_reg_rules = 6,
        /*
         * This alpha2 is bogus, we leave it here just for stupid
         * backward compatibility
         */
        .alpha2 =  "EU",
        .reg_rules = {
                /* IEEE 802.11b/g, channels 1..13 */
                REG_RULE(2412-10, 2472+10, 40, 6, 20, 0),
                /* IEEE 802.11a, channel 36 */
                REG_RULE(5180-10, 5180+10, 40, 6, 23,
                        NL80211_RRF_PASSIVE_SCAN),
                /* IEEE 802.11a, channel 40 */
                REG_RULE(5200-10, 5200+10, 40, 6, 23,
                        NL80211_RRF_PASSIVE_SCAN),
                /* IEEE 802.11a, channel 44 */
                REG_RULE(5220-10, 5220+10, 40, 6, 23,
                        NL80211_RRF_PASSIVE_SCAN),
                /* IEEE 802.11a, channels 48..64 */
                REG_RULE(5240-10, 5320+10, 40, 6, 20,
                        NL80211_RRF_NO_IBSS |
                        NL80211_RRF_DFS),
                /* IEEE 802.11a, channels 100..140 */
                REG_RULE(5500-10, 5700+10, 40, 6, 30,
                        NL80211_RRF_NO_IBSS |
                        NL80211_RRF_DFS),
        }
};

static const struct ieee80211_regdomain *static_regdom(char *alpha2)
{
        if (alpha2[0] == 'U' && alpha2[1] == 'S')
                return &us_regdom;
        if (alpha2[0] == 'J' && alpha2[1] == 'P')
                return &jp_regdom;
        if (alpha2[0] == 'E' && alpha2[1] == 'U')
                return &eu_regdom;
        /* Default, as per the old rules */
        return &us_regdom;
}

static bool is_old_static_regdom(const struct ieee80211_regdomain *rd)
{
        if (rd == &us_regdom || rd == &jp_regdom || rd == &eu_regdom)
                return true;
        return false;
}
#else
static inline bool is_old_static_regdom(const struct ieee80211_regdomain *rd)
{
        return false;
}
#endif

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;
        if (is_old_static_regdom(cfg80211_regdomain))
                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;
}

/**
 * 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;
}

/*
 * 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");

        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;
}

/* Returns value in KHz */
static u32 freq_max_bandwidth(const struct ieee80211_freq_range *freq_range,
        u32 freq)
{
        unsigned int i;
        for (i = 0; i < ARRAY_SIZE(supported_bandwidths); i++) {
                u32 start_freq_khz = freq - supported_bandwidths[i]/2;
                u32 end_freq_khz = freq + supported_bandwidths[i]/2;
                if (start_freq_khz >= freq_range->start_freq_khz &&
                        end_freq_khz <= freq_range->end_freq_khz)
                        return supported_bandwidths[i];
        }
        return 0;
}

/**
 * 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
}

/*
 * 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(
                                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;
                }

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

                country_ie += 3;
                country_ie_len -= 3;
                num_rules++;

                /*
                 * 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;
                }

                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 (triplet->chans.first_channel <= 14)
                        end_channel = triplet->chans.first_channel +
                                triplet->chans.num_channels;
                else
                        end_channel =  triplet->chans.first_channel +
                                (4 * (triplet->chans.num_channels - 1));

                /*
                 * 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(100);

                country_ie += 3;
                country_ie_len -= 3;
                i++;

                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 *bandwidth,
                              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;
        u32 max_bandwidth = 0;

        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);

                max_bandwidth = freq_max_bandwidth(fr, center_freq);

                if (max_bandwidth && *bandwidth <= max_bandwidth) {
                        *reg_rule = rr;
                        *bandwidth = max_bandwidth;
                        break;
                }
        }

        if (!band_rule_found)
                return -ERANGE;

        return !max_bandwidth;
}
EXPORT_SYMBOL(freq_reg_info);

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

static void handle_channel(struct wiphy *wiphy, enum ieee80211_band band,
                           unsigned int chan_idx)
{
        int r;
        u32 flags;
        u32 max_bandwidth = 0;
        const struct ieee80211_reg_rule *reg_rule = NULL;
        const struct ieee80211_power_rule *power_rule = 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),
                &max_bandwidth, &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) {
#ifdef CONFIG_CFG80211_REG_DEBUG
                        printk(KERN_DEBUG "cfg80211: Leaving channel %d MHz "
                                "intact on %s - no rule found in band on "
                                "Country IE\n",
                                chan->center_freq, wiphy_name(wiphy));
#endif
                } else {
                /*
                 * In this case we know the country IE has at least one reg rule
                 * for the band so we respect its band definitions
                 */
#ifdef CONFIG_CFG80211_REG_DEBUG
                        if (last_request->initiator ==
                            NL80211_REGDOM_SET_BY_COUNTRY_IE)
                                printk(KERN_DEBUG "cfg80211: Disabling "
                                        "channel %d MHz on %s due to "
                                        "Country IE\n",
                                        chan->center_freq, wiphy_name(wiphy));
#endif
                        flags |= IEEE80211_CHAN_DISABLED;
                        chan->flags = flags;
                }
                return;
        }

        power_rule = &reg_rule->power_rule;

        if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER &&
            request_wiphy && request_wiphy == wiphy &&
            request_wiphy->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);
                chan->max_antenna_gain = chan->orig_mag =
                        (int) MBI_TO_DBI(power_rule->max_antenna_gain);
                chan->max_bandwidth = KHZ_TO_MHZ(max_bandwidth);
                chan->max_power = chan->orig_mpwr =
                        (int) MBM_TO_DBM(power_rule->max_eirp);
                return;
        }

        chan->flags = flags | map_regdom_flags(reg_rule->flags);
        chan->max_antenna_gain = min(chan->orig_mag,
                (int) MBI_TO_DBI(power_rule->max_antenna_gain));
        chan->max_bandwidth = KHZ_TO_MHZ(max_bandwidth);
        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->custom_regulatory)
                return true;
        /*
         * wiphy->regd will be set once the device has its own
         * desired regulatory domain set
         */
        if (wiphy->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 *drv;

        list_for_each_entry(drv, &cfg80211_drv_list, list)
                wiphy_update_regulatory(&drv->wiphy, initiator);
}

static void handle_reg_beacon(struct wiphy *wiphy,
                              unsigned int chan_idx,
                              struct reg_beacon *reg_beacon)
{
#ifdef CONFIG_CFG80211_REG_DEBUG
#define REG_DEBUG_BEACON_FLAG(desc) \
        printk(KERN_DEBUG "cfg80211: Enabling " desc " on " \
                "frequency: %d MHz (Ch %d) on %s\n", \
                reg_beacon->chan.center_freq, \
                ieee80211_frequency_to_channel(reg_beacon->chan.center_freq), \
                wiphy_name(wiphy));
#else
#define REG_DEBUG_BEACON_FLAG(desc) do {} while (0)
#endif
        struct ieee80211_supported_band *sband;
        struct ieee80211_channel *chan;

        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->flags & IEEE80211_CHAN_PASSIVE_SCAN) {
                chan->flags &= ~IEEE80211_CHAN_PASSIVE_SCAN;
                REG_DEBUG_BEACON_FLAG("active scanning");
        }

        if (chan->flags & IEEE80211_CHAN_NO_IBSS) {
                chan->flags &= ~IEEE80211_CHAN_NO_IBSS;
                REG_DEBUG_BEACON_FLAG("beaconing");
        }

        chan->beacon_found = true;
#undef REG_DEBUG_BEACON_FLAG
}

/*
 * 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->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);
}

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);
        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 max_bandwidth = 0;
        const struct ieee80211_reg_rule *reg_rule = NULL;
        const struct ieee80211_power_rule *power_rule = NULL;
        struct ieee80211_supported_band *sband;
        struct ieee80211_channel *chan;

        assert_cfg80211_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),
                &max_bandwidth, &reg_rule, regd);

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

        power_rule = &reg_rule->power_rule;

        chan->flags |= map_regdom_flags(reg_rule->flags);
        chan->max_antenna_gain = (int) MBI_TO_DBI(power_rule->max_antenna_gain);
        chan->max_bandwidth = KHZ_TO_MHZ(max_bandwidth);
        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;

        mutex_lock(&cfg80211_mutex);
        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                if (wiphy->bands[band])
                        handle_band_custom(wiphy, band, regd);
        }
        mutex_unlock(&cfg80211_mutex);
}
EXPORT_SYMBOL(wiphy_apply_custom_regulatory);

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;
}

/*
 * 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 -EINVAL;
        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
                                 * 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 (is_old_static_regdom(cfg80211_regdomain))
                                return 0;
                        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 (!is_old_static_regdom(cfg80211_regdomain) &&
                    !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
 */
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;

        /* 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);

        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->strict_regulatory)
                wiphy_update_regulatory(wiphy, reg_request->initiator);
out:
        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 *drv;
        struct reg_beacon *pending_beacon, *tmp;

        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(drv, &cfg80211_drv_list, list)
                        wiphy_update_new_beacon(&drv->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 once during cfg80211_init() */
static int regulatory_hint_core(const char *alpha2)
{
        struct regulatory_request *request;

        BUG_ON(last_request);

        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;

        queue_regulatory_request(request);

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

        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);

static bool reg_same_country_ie_hint(struct wiphy *wiphy,
                        u32 country_ie_checksum)
{
        struct wiphy *request_wiphy;

        assert_cfg80211_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;
}

void regulatory_hint_11d(struct wiphy *wiphy,
                        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(&cfg80211_mutex);

        if (unlikely(!last_request)) {
                mutex_unlock(&cfg80211_mutex);
                return;
        }

        /* 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 for *every* beacon processed for the BSSID, so
         * we optimize an early check to exit out early if we don't have to
         * do anything
         */
        if (likely(last_request->initiator ==
            NL80211_REGDOM_SET_BY_COUNTRY_IE &&
            wiphy_idx_valid(last_request->wiphy_idx))) {
                struct cfg80211_registered_device *drv_last_ie;

                drv_last_ie =
                        cfg80211_drv_by_wiphy_idx(last_request->wiphy_idx);

                /*
                 * Lets keep this simple -- we trust the first AP
                 * after we intersect with CRDA
                 */
                if (likely(&drv_last_ie->wiphy == wiphy)) {
                        /*
                         * Ignore IEs coming in on this wiphy with
                         * the same alpha2 and environment cap
                         */
                        if (likely(alpha2_equal(drv_last_ie->country_ie_alpha2,
                                  alpha2) &&
                                  env == drv_last_ie->env)) {
                                goto out;
                        }
                        /*
                         * the wiphy moved on to another BSSID or the AP
                         * was reconfigured. XXX: We need to deal with the
                         * case where the user suspends and goes to goes
                         * to another country, and then gets IEs from an
                         * AP with different settings
                         */
                        goto out;
                } else {
                        /*
                         * Ignore IEs coming in on two separate wiphys with
                         * the same alpha2 and environment cap
                         */
                        if (likely(alpha2_equal(drv_last_ie->country_ie_alpha2,
                                  alpha2) &&
                                  env == drv_last_ie->env)) {
                                goto out;
                        }
                        /* We could potentially intersect though */
                        goto out;
                }
        }

        rd = country_ie_2_rd(country_ie, country_ie_len, &checksum);
        if (!rd)
                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(&cfg80211_mutex);

        queue_regulatory_request(request);

        return;

free_rd_out:
        kfree(rd);
out:
        mutex_unlock(&cfg80211_mutex);
}
EXPORT_SYMBOL(regulatory_hint_11d);

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;

#ifdef CONFIG_CFG80211_REG_DEBUG
        printk(KERN_DEBUG "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));
#endif
        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 "\t(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 "\t(%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 "\t(%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 *drv;
                        drv = cfg80211_drv_by_wiphy_idx(
                                last_request->wiphy_idx);
                        if (drv) {
                                printk(KERN_INFO "cfg80211: Current regulatory "
                                        "domain updated by AP to: %c%c\n",
                                        drv->country_ie_alpha2[0],
                                        drv->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 *drv = 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 (!is_old_static_regdom(cfg80211_regdomain) &&
                    !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
                 */

                BUG_ON(request_wiphy->regd);

                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;

        drv = wiphy_to_dev(request_wiphy);

        drv->country_ie_alpha2[0] = rd->alpha2[0];
        drv->country_ie_alpha2[1] = rd->alpha2[1];
        drv->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();

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

        return r;
}

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

        assert_cfg80211_lock();

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

        kfree(wiphy->regd);
        if (!last_request || !request_wiphy)
                return;
        if (request_wiphy != wiphy)
                return;
        last_request->wiphy_idx = WIPHY_IDX_STALE;
        last_request->country_ie_env = ENVIRON_ANY;
}

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);

#ifdef CONFIG_WIRELESS_OLD_REGULATORY
        cfg80211_regdomain = static_regdom(ieee80211_regdom);

        printk(KERN_INFO "cfg80211: Using static regulatory domain info\n");
        print_regdomain_info(cfg80211_regdomain);
        /*
         * The old code still requests for a new regdomain and if
         * you have CRDA you get it updated, otherwise you get
         * stuck with the static values. Since "EU" is not a valid
         * ISO / IEC 3166 alpha2 code we can't expect userpace to
         * give us a regulatory domain for it. We need last_request
         * iniitalized though so lets just send a request which we
         * know will be ignored... this crap will be removed once
         * OLD_REG dies.
         */
        err = regulatory_hint_core(ieee80211_regdom);
#else
        cfg80211_regdomain = cfg80211_world_regdom;

        err = regulatory_hint_core(ieee80211_regdom);
#endif
        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
        }

        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);

        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(&cfg80211_mutex);
}