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[cascardo/linux.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 2008-2011  Luis R. Rodriguez <mcgrof@qca.qualcomm.com>
 * Copyright 2013-2014  Intel Mobile Communications GmbH
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */


/**
 * 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.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/ctype.h>
#include <linux/nl80211.h>
#include <linux/platform_device.h>
#include <linux/moduleparam.h>
#include <net/cfg80211.h>
#include "core.h"
#include "reg.h"
#include "rdev-ops.h"
#include "regdb.h"
#include "nl80211.h"

#ifdef CONFIG_CFG80211_REG_DEBUG
#define REG_DBG_PRINT(format, args...)                  \
        printk(KERN_DEBUG pr_fmt(format), ##args)
#else
#define REG_DBG_PRINT(args...)
#endif

/*
 * Grace period we give before making sure all current interfaces reside on
 * channels allowed by the current regulatory domain.
 */
#define REG_ENFORCE_GRACE_MS 60000

/**
 * enum reg_request_treatment - regulatory request treatment
 *
 * @REG_REQ_OK: continue processing the regulatory request
 * @REG_REQ_IGNORE: ignore the regulatory request
 * @REG_REQ_INTERSECT: the regulatory domain resulting from this request should
 *      be intersected with the current one.
 * @REG_REQ_ALREADY_SET: the regulatory request will not change the current
 *      regulatory settings, and no further processing is required.
 * @REG_REQ_USER_HINT_HANDLED: a non alpha2  user hint was handled and no
 *      further processing is required, i.e., not need to update last_request
 *      etc. This should be used for user hints that do not provide an alpha2
 *      but some other type of regulatory hint, i.e., indoor operation.
 */
enum reg_request_treatment {
        REG_REQ_OK,
        REG_REQ_IGNORE,
        REG_REQ_INTERSECT,
        REG_REQ_ALREADY_SET,
        REG_REQ_USER_HINT_HANDLED,
};

static struct regulatory_request core_request_world = {
        .initiator = NL80211_REGDOM_SET_BY_CORE,
        .alpha2[0] = '0',
        .alpha2[1] = '0',
        .intersect = false,
        .processed = true,
        .country_ie_env = ENVIRON_ANY,
};

/*
 * Receipt of information from last regulatory request,
 * protected by RTNL (and can be accessed with RCU protection)
 */
static struct regulatory_request __rcu *last_request =
        (void __rcu *)&core_request_world;

/* 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.
 * (protected by RTNL, can be read under RCU)
 */
const struct ieee80211_regdomain __rcu *cfg80211_regdomain;

/*
 * Number of devices that registered to the core
 * that support cellular base station regulatory hints
 * (protected by RTNL)
 */
static int reg_num_devs_support_basehint;

/*
 * State variable indicating if the platform on which the devices
 * are attached is operating in an indoor environment. The state variable
 * is relevant for all registered devices.
 * (protected by RTNL)
 */
static bool reg_is_indoor;

static const struct ieee80211_regdomain *get_cfg80211_regdom(void)
{
        return rtnl_dereference(cfg80211_regdomain);
}

static const struct ieee80211_regdomain *get_wiphy_regdom(struct wiphy *wiphy)
{
        return rtnl_dereference(wiphy->regd);
}

static const char *reg_dfs_region_str(enum nl80211_dfs_regions dfs_region)
{
        switch (dfs_region) {
        case NL80211_DFS_UNSET:
                return "unset";
        case NL80211_DFS_FCC:
                return "FCC";
        case NL80211_DFS_ETSI:
                return "ETSI";
        case NL80211_DFS_JP:
                return "JP";
        }
        return "Unknown";
}

enum nl80211_dfs_regions reg_get_dfs_region(struct wiphy *wiphy)
{
        const struct ieee80211_regdomain *regd = NULL;
        const struct ieee80211_regdomain *wiphy_regd = NULL;

        regd = get_cfg80211_regdom();
        if (!wiphy)
                goto out;

        wiphy_regd = get_wiphy_regdom(wiphy);
        if (!wiphy_regd)
                goto out;

        if (wiphy_regd->dfs_region == regd->dfs_region)
                goto out;

        REG_DBG_PRINT("%s: device specific dfs_region "
                      "(%s) disagrees with cfg80211's "
                      "central dfs_region (%s)\n",
                      dev_name(&wiphy->dev),
                      reg_dfs_region_str(wiphy_regd->dfs_region),
                      reg_dfs_region_str(regd->dfs_region));

out:
        return regd->dfs_region;
}

static void rcu_free_regdom(const struct ieee80211_regdomain *r)
{
        if (!r)
                return;
        kfree_rcu((struct ieee80211_regdomain *)r, rcu_head);
}

static struct regulatory_request *get_last_request(void)
{
        return rcu_dereference_rtnl(last_request);
}

/* 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;
};

static void reg_check_chans_work(struct work_struct *work);
static DECLARE_DELAYED_WORK(reg_check_chans, reg_check_chans_work);

static void reg_todo(struct work_struct *work);
static DECLARE_WORK(reg_work, reg_todo);

static void reg_timeout_work(struct work_struct *work);
static DECLARE_DELAYED_WORK(reg_timeout, reg_timeout_work);

/* We keep a static world regulatory domain in case of the absence of CRDA */
static const struct ieee80211_regdomain world_regdom = {
        .n_reg_rules = 6,
        .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. */
                REG_RULE(2467-10, 2472+10, 40, 6, 20,
                        NL80211_RRF_NO_IR),
                /* 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_NO_IR |
                        NL80211_RRF_NO_OFDM),
                /* IEEE 802.11a, channel 36..48 */
                REG_RULE(5180-10, 5240+10, 160, 6, 20,
                        NL80211_RRF_NO_IR),

                /* IEEE 802.11a, channel 52..64 - DFS required */
                REG_RULE(5260-10, 5320+10, 160, 6, 20,
                        NL80211_RRF_NO_IR |
                        NL80211_RRF_DFS),

                /* IEEE 802.11a, channel 100..144 - DFS required */
                REG_RULE(5500-10, 5720+10, 160, 6, 20,
                        NL80211_RRF_NO_IR |
                        NL80211_RRF_DFS),

                /* IEEE 802.11a, channel 149..165 */
                REG_RULE(5745-10, 5825+10, 80, 6, 20,
                        NL80211_RRF_NO_IR),

                /* IEEE 802.11ad (60gHz), channels 1..3 */
                REG_RULE(56160+2160*1-1080, 56160+2160*3+1080, 2160, 0, 0, 0),
        }
};

/* protected by RTNL */
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 reg_free_request(struct regulatory_request *request)
{
        if (request != get_last_request())
                kfree(request);
}

static void reg_free_last_request(void)
{
        struct regulatory_request *lr = get_last_request();

        if (lr != &core_request_world && lr)
                kfree_rcu(lr, rcu_head);
}

static void reg_update_last_request(struct regulatory_request *request)
{
        struct regulatory_request *lr;

        lr = get_last_request();
        if (lr == request)
                return;

        reg_free_last_request();
        rcu_assign_pointer(last_request, request);
}

static void reset_regdomains(bool full_reset,
                             const struct ieee80211_regdomain *new_regdom)
{
        const struct ieee80211_regdomain *r;

        ASSERT_RTNL();

        r = get_cfg80211_regdom();

        /* avoid freeing static information or freeing something twice */
        if (r == cfg80211_world_regdom)
                r = NULL;
        if (cfg80211_world_regdom == &world_regdom)
                cfg80211_world_regdom = NULL;
        if (r == &world_regdom)
                r = NULL;

        rcu_free_regdom(r);
        rcu_free_regdom(cfg80211_world_regdom);

        cfg80211_world_regdom = &world_regdom;
        rcu_assign_pointer(cfg80211_regdomain, new_regdom);

        if (!full_reset)
                return;

        reg_update_last_request(&core_request_world);
}

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

        lr = get_last_request();

        WARN_ON(!lr);

        reset_regdomains(false, rd);

        cfg80211_world_regdom = rd;
}

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

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

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
         */
        return alpha2[0] == '9' && alpha2[1] == '9';
}

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
         */
        return alpha2[0] == '9' && alpha2[1] == '8';
}

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

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

static bool regdom_changes(const char *alpha2)
{
        const struct ieee80211_regdomain *r = get_cfg80211_regdom();

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

/*
 * 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;
}

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

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

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

        return regd;
}

#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_MUTEX(reg_regdb_search_mutex);

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

        rtnl_lock();

        mutex_lock(&reg_regdb_search_mutex);
        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 (alpha2_equal(request->alpha2, curdom->alpha2)) {
                                regdom = reg_copy_regd(curdom);
                                break;
                        }
                }

                kfree(request);
        }
        mutex_unlock(&reg_regdb_search_mutex);

        if (!IS_ERR_OR_NULL(regdom))
                set_regdom(regdom);

        rtnl_unlock();
}

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);

        mutex_lock(&reg_regdb_search_mutex);
        list_add_tail(&request->list, &reg_regdb_search_list);
        mutex_unlock(&reg_regdb_search_mutex);

        schedule_work(&reg_regdb_work);
}

/* Feel free to add any other sanity checks here */
static void reg_regdb_size_check(void)
{
        /* We should ideally BUILD_BUG_ON() but then random builds would fail */
        WARN_ONCE(!reg_regdb_size, "db.txt is empty, you should update it...");
}
#else
static inline void reg_regdb_size_check(void) {}
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[12];
        char *env[] = { country, NULL };

        snprintf(country, sizeof(country), "COUNTRY=%c%c",
                 alpha2[0], alpha2[1]);

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

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

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

static enum reg_request_treatment
reg_call_crda(struct regulatory_request *request)
{
        if (call_crda(request->alpha2))
                return REG_REQ_IGNORE;
        return REG_REQ_OK;
}

bool reg_is_valid_request(const char *alpha2)
{
        struct regulatory_request *lr = get_last_request();

        if (!lr || lr->processed)
                return false;

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

static const struct ieee80211_regdomain *reg_get_regdomain(struct wiphy *wiphy)
{
        struct regulatory_request *lr = get_last_request();

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

        return get_cfg80211_regdom();
}

static unsigned int
reg_get_max_bandwidth_from_range(const struct ieee80211_regdomain *rd,
                                 const struct ieee80211_reg_rule *rule)
{
        const struct ieee80211_freq_range *freq_range = &rule->freq_range;
        const struct ieee80211_freq_range *freq_range_tmp;
        const struct ieee80211_reg_rule *tmp;
        u32 start_freq, end_freq, idx, no;

        for (idx = 0; idx < rd->n_reg_rules; idx++)
                if (rule == &rd->reg_rules[idx])
                        break;

        if (idx == rd->n_reg_rules)
                return 0;

        /* get start_freq */
        no = idx;

        while (no) {
                tmp = &rd->reg_rules[--no];
                freq_range_tmp = &tmp->freq_range;

                if (freq_range_tmp->end_freq_khz < freq_range->start_freq_khz)
                        break;

                freq_range = freq_range_tmp;
        }

        start_freq = freq_range->start_freq_khz;

        /* get end_freq */
        freq_range = &rule->freq_range;
        no = idx;

        while (no < rd->n_reg_rules - 1) {
                tmp = &rd->reg_rules[++no];
                freq_range_tmp = &tmp->freq_range;

                if (freq_range_tmp->start_freq_khz > freq_range->end_freq_khz)
                        break;

                freq_range = freq_range_tmp;
        }

        end_freq = freq_range->end_freq_khz;

        return end_freq - start_freq;
}

unsigned int reg_get_max_bandwidth(const struct ieee80211_regdomain *rd,
                                   const struct ieee80211_reg_rule *rule)
{
        unsigned int bw = reg_get_max_bandwidth_from_range(rd, rule);

        if (rule->flags & NL80211_RRF_NO_160MHZ)
                bw = min_t(unsigned int, bw, MHZ_TO_KHZ(80));
        if (rule->flags & NL80211_RRF_NO_80MHZ)
                bw = min_t(unsigned int, bw, MHZ_TO_KHZ(40));

        /*
         * HT40+/HT40- limits are handled per-channel. Only limit BW if both
         * are not allowed.
         */
        if (rule->flags & NL80211_RRF_NO_HT40MINUS &&
            rule->flags & NL80211_RRF_NO_HT40PLUS)
                bw = min_t(unsigned int, bw, MHZ_TO_KHZ(20));

        return bw;
}

/* 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", the "5 GHz band" and the "60GHz 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 for the 2.4 and 5 GHz bands, and by more than 10 GHz for the
 * 60 GHz band.
 * 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
        /*
         * From 802.11ad: directional multi-gigabit (DMG):
         * Pertaining to operation in a frequency band containing a channel
         * with the Channel starting frequency above 45 GHz.
         */
        u32 limit = freq_khz > 45 * ONE_GHZ_IN_KHZ ?
                        10 * ONE_GHZ_IN_KHZ : 2 * ONE_GHZ_IN_KHZ;
        if (abs(freq_khz - freq_range->start_freq_khz) <= limit)
                return true;
        if (abs(freq_khz - freq_range->end_freq_khz) <= limit)
                return true;
        return false;
#undef ONE_GHZ_IN_KHZ
}

/*
 * Later on we can perhaps use the more restrictive DFS
 * region but we don't have information for that yet so
 * for now simply disallow conflicts.
 */
static enum nl80211_dfs_regions
reg_intersect_dfs_region(const enum nl80211_dfs_regions dfs_region1,
                         const enum nl80211_dfs_regions dfs_region2)
{
        if (dfs_region1 != dfs_region2)
                return NL80211_DFS_UNSET;
        return dfs_region1;
}

/*
 * Helper for regdom_intersect(), this does the real
 * mathematical intersection fun
 */
static int reg_rules_intersect(const struct ieee80211_regdomain *rd1,
                               const struct ieee80211_regdomain *rd2,
                               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, max_bandwidth1, max_bandwidth2;

        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);

        max_bandwidth1 = freq_range1->max_bandwidth_khz;
        max_bandwidth2 = freq_range2->max_bandwidth_khz;

        if (rule1->flags & NL80211_RRF_AUTO_BW)
                max_bandwidth1 = reg_get_max_bandwidth(rd1, rule1);
        if (rule2->flags & NL80211_RRF_AUTO_BW)
                max_bandwidth2 = reg_get_max_bandwidth(rd2, rule2);

        freq_range->max_bandwidth_khz = min(max_bandwidth1, max_bandwidth2);

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

        /*
         * In case NL80211_RRF_AUTO_BW requested for both rules
         * set AUTO_BW in intersected rule also. Next we will
         * calculate BW correctly in handle_channel function.
         * In other case remove AUTO_BW flag while we calculate
         * maximum bandwidth correctly and auto calculation is
         * not required.
         */
        if ((rule1->flags & NL80211_RRF_AUTO_BW) &&
            (rule2->flags & NL80211_RRF_AUTO_BW))
                intersected_rule->flags |= NL80211_RRF_AUTO_BW;
        else
                intersected_rule->flags &= ~NL80211_RRF_AUTO_BW;

        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->dfs_cac_ms = max(rule1->dfs_cac_ms,
                                           rule2->dfs_cac_ms);

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

        return 0;
}

/* check whether old rule contains new rule */
static bool rule_contains(struct ieee80211_reg_rule *r1,
                          struct ieee80211_reg_rule *r2)
{
        /* for simplicity, currently consider only same flags */
        if (r1->flags != r2->flags)
                return false;

        /* verify r1 is more restrictive */
        if ((r1->power_rule.max_antenna_gain >
             r2->power_rule.max_antenna_gain) ||
            r1->power_rule.max_eirp > r2->power_rule.max_eirp)
                return false;

        /* make sure r2's range is contained within r1 */
        if (r1->freq_range.start_freq_khz > r2->freq_range.start_freq_khz ||
            r1->freq_range.end_freq_khz < r2->freq_range.end_freq_khz)
                return false;

        /* and finally verify that r1.max_bw >= r2.max_bw */
        if (r1->freq_range.max_bandwidth_khz <
            r2->freq_range.max_bandwidth_khz)
                return false;

        return true;
}

/* add or extend current rules. do nothing if rule is already contained */
static void add_rule(struct ieee80211_reg_rule *rule,
                     struct ieee80211_reg_rule *reg_rules, u32 *n_rules)
{
        struct ieee80211_reg_rule *tmp_rule;
        int i;

        for (i = 0; i < *n_rules; i++) {
                tmp_rule = &reg_rules[i];
                /* rule is already contained - do nothing */
                if (rule_contains(tmp_rule, rule))
                        return;

                /* extend rule if possible */
                if (rule_contains(rule, tmp_rule)) {
                        memcpy(tmp_rule, rule, sizeof(*rule));
                        return;
                }
        }

        memcpy(&reg_rules[*n_rules], rule, sizeof(*rule));
        (*n_rules)++;
}

/**
 * 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;
        const struct ieee80211_reg_rule *rule1, *rule2;
        struct ieee80211_reg_rule intersected_rule;
        struct ieee80211_regdomain *rd;

        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(rd1, rd2, rule1, rule2,
                                                 &intersected_rule))
                                num_rules++;
                }
        }

        if (!num_rules)
                return NULL;

        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;

        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];
                        r = reg_rules_intersect(rd1, rd2, rule1, rule2,
                                                &intersected_rule);
                        /*
                         * No need to memset here the intersected rule here as
                         * we're not using the stack anymore
                         */
                        if (r)
                                continue;

                        add_rule(&intersected_rule, rd->reg_rules,
                                 &rd->n_reg_rules);
                }
        }

        rd->alpha2[0] = '9';
        rd->alpha2[1] = '8';
        rd->dfs_region = reg_intersect_dfs_region(rd1->dfs_region,
                                                  rd2->dfs_region);

        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_NO_IR_ALL)
                channel_flags |= IEEE80211_CHAN_NO_IR;
        if (rd_flags & NL80211_RRF_DFS)
                channel_flags |= IEEE80211_CHAN_RADAR;
        if (rd_flags & NL80211_RRF_NO_OFDM)
                channel_flags |= IEEE80211_CHAN_NO_OFDM;
        if (rd_flags & NL80211_RRF_NO_OUTDOOR)
                channel_flags |= IEEE80211_CHAN_INDOOR_ONLY;
        if (rd_flags & NL80211_RRF_GO_CONCURRENT)
                channel_flags |= IEEE80211_CHAN_GO_CONCURRENT;
        if (rd_flags & NL80211_RRF_NO_HT40MINUS)
                channel_flags |= IEEE80211_CHAN_NO_HT40MINUS;
        if (rd_flags & NL80211_RRF_NO_HT40PLUS)
                channel_flags |= IEEE80211_CHAN_NO_HT40PLUS;
        if (rd_flags & NL80211_RRF_NO_80MHZ)
                channel_flags |= IEEE80211_CHAN_NO_80MHZ;
        if (rd_flags & NL80211_RRF_NO_160MHZ)
                channel_flags |= IEEE80211_CHAN_NO_160MHZ;
        return channel_flags;
}

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

        if (!regd)
                return ERR_PTR(-EINVAL);

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

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

                /*
                 * 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, MHZ_TO_KHZ(20));

                if (band_rule_found && bw_fits)
                        return rr;
        }

        if (!band_rule_found)
                return ERR_PTR(-ERANGE);

        return ERR_PTR(-EINVAL);
}

const struct ieee80211_reg_rule *freq_reg_info(struct wiphy *wiphy,
                                               u32 center_freq)
{
        const struct ieee80211_regdomain *regd;

        regd = reg_get_regdomain(wiphy);

        return freq_reg_info_regd(wiphy, center_freq, regd);
}
EXPORT_SYMBOL(freq_reg_info);

const char *reg_initiator_name(enum nl80211_reg_initiator initiator)
{
        switch (initiator) {
        case NL80211_REGDOM_SET_BY_CORE:
                return "core";
        case NL80211_REGDOM_SET_BY_USER:
                return "user";
        case NL80211_REGDOM_SET_BY_DRIVER:
                return "driver";
        case NL80211_REGDOM_SET_BY_COUNTRY_IE:
                return "country IE";
        default:
                WARN_ON(1);
                return "bug";
        }
}
EXPORT_SYMBOL(reg_initiator_name);

#ifdef CONFIG_CFG80211_REG_DEBUG
static void chan_reg_rule_print_dbg(const struct ieee80211_regdomain *regd,
                                    struct ieee80211_channel *chan,
                                    const struct ieee80211_reg_rule *reg_rule)
{
        const struct ieee80211_power_rule *power_rule;
        const struct ieee80211_freq_range *freq_range;
        char max_antenna_gain[32], bw[32];

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

        if (!power_rule->max_antenna_gain)
                snprintf(max_antenna_gain, sizeof(max_antenna_gain), "N/A");
        else
                snprintf(max_antenna_gain, sizeof(max_antenna_gain), "%d",
                         power_rule->max_antenna_gain);

        if (reg_rule->flags & NL80211_RRF_AUTO_BW)
                snprintf(bw, sizeof(bw), "%d KHz, %d KHz AUTO",
                         freq_range->max_bandwidth_khz,
                         reg_get_max_bandwidth(regd, reg_rule));
        else
                snprintf(bw, sizeof(bw), "%d KHz",
                         freq_range->max_bandwidth_khz);

        REG_DBG_PRINT("Updating information on frequency %d MHz with regulatory rule:\n",
                      chan->center_freq);

        REG_DBG_PRINT("%d KHz - %d KHz @ %s), (%s mBi, %d mBm)\n",
                      freq_range->start_freq_khz, freq_range->end_freq_khz,
                      bw, max_antenna_gain,
                      power_rule->max_eirp);
}
#else
static void chan_reg_rule_print_dbg(const struct ieee80211_regdomain *regd,
                                    struct ieee80211_channel *chan,
                                    const struct ieee80211_reg_rule *reg_rule)
{
        return;
}
#endif

/*
 * 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).
 */
static void handle_channel(struct wiphy *wiphy,
                           enum nl80211_reg_initiator initiator,
                           struct ieee80211_channel *chan)
{
        u32 flags, 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 wiphy *request_wiphy = NULL;
        struct regulatory_request *lr = get_last_request();
        const struct ieee80211_regdomain *regd;
        u32 max_bandwidth_khz;

        request_wiphy = wiphy_idx_to_wiphy(lr->wiphy_idx);

        flags = chan->orig_flags;

        reg_rule = freq_reg_info(wiphy, MHZ_TO_KHZ(chan->center_freq));
        if (IS_ERR(reg_rule)) {
                /*
                 * We will disable all channels that do not match our
                 * received regulatory rule unless the hint is coming
                 * from a Country IE and the Country IE had no information
                 * about a band. The IEEE 802.11 spec allows for an AP
                 * to send only a subset of the regulatory rules allowed,
                 * so an AP in the US that only supports 2.4 GHz may only send
                 * a country IE with information for the 2.4 GHz band
                 * while 5 GHz is still supported.
                 */
                if (initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE &&
                    PTR_ERR(reg_rule) == -ERANGE)
                        return;

                if (lr->initiator == NL80211_REGDOM_SET_BY_DRIVER &&
                    request_wiphy && request_wiphy == wiphy &&
                    request_wiphy->regulatory_flags & REGULATORY_STRICT_REG) {
                        REG_DBG_PRINT("Disabling freq %d MHz for good\n",
                                      chan->center_freq);
                        chan->orig_flags |= IEEE80211_CHAN_DISABLED;
                        chan->flags = chan->orig_flags;
                } else {
                        REG_DBG_PRINT("Disabling freq %d MHz\n",
                                      chan->center_freq);
                        chan->flags |= IEEE80211_CHAN_DISABLED;
                }
                return;
        }

        regd = reg_get_regdomain(wiphy);
        chan_reg_rule_print_dbg(regd, chan, reg_rule);

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

        max_bandwidth_khz = freq_range->max_bandwidth_khz;
        /* Check if auto calculation requested */
        if (reg_rule->flags & NL80211_RRF_AUTO_BW)
                max_bandwidth_khz = reg_get_max_bandwidth(regd, reg_rule);

        if (max_bandwidth_khz < MHZ_TO_KHZ(40))
                bw_flags = IEEE80211_CHAN_NO_HT40;
        if (max_bandwidth_khz < MHZ_TO_KHZ(80))
                bw_flags |= IEEE80211_CHAN_NO_80MHZ;
        if (max_bandwidth_khz < MHZ_TO_KHZ(160))
                bw_flags |= IEEE80211_CHAN_NO_160MHZ;

        if (lr->initiator == NL80211_REGDOM_SET_BY_DRIVER &&
            request_wiphy && request_wiphy == wiphy &&
            request_wiphy->regulatory_flags & REGULATORY_STRICT_REG) {
                /*
                 * This guarantees 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_reg_power = chan->max_power = chan->orig_mpwr =
                        (int) MBM_TO_DBM(power_rule->max_eirp);

                if (chan->flags & IEEE80211_CHAN_RADAR) {
                        chan->dfs_cac_ms = IEEE80211_DFS_MIN_CAC_TIME_MS;
                        if (reg_rule->dfs_cac_ms)
                                chan->dfs_cac_ms = reg_rule->dfs_cac_ms;
                }

                return;
        }

        chan->dfs_state = NL80211_DFS_USABLE;
        chan->dfs_state_entered = jiffies;

        chan->beacon_found = false;
        chan->flags = flags | bw_flags | map_regdom_flags(reg_rule->flags);
        chan->max_antenna_gain =
                min_t(int, chan->orig_mag,
                      MBI_TO_DBI(power_rule->max_antenna_gain));
        chan->max_reg_power = (int) MBM_TO_DBM(power_rule->max_eirp);

        if (chan->flags & IEEE80211_CHAN_RADAR) {
                if (reg_rule->dfs_cac_ms)
                        chan->dfs_cac_ms = reg_rule->dfs_cac_ms;
                else
                        chan->dfs_cac_ms = IEEE80211_DFS_MIN_CAC_TIME_MS;
        }

        if (chan->orig_mpwr) {
                /*
                 * Devices that use REGULATORY_COUNTRY_IE_FOLLOW_POWER
                 * will always follow the passed country IE power settings.
                 */
                if (initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE &&
                    wiphy->regulatory_flags & REGULATORY_COUNTRY_IE_FOLLOW_POWER)
                        chan->max_power = chan->max_reg_power;
                else
                        chan->max_power = min(chan->orig_mpwr,
                                              chan->max_reg_power);
        } else
                chan->max_power = chan->max_reg_power;
}

static void handle_band(struct wiphy *wiphy,
                        enum nl80211_reg_initiator initiator,
                        struct ieee80211_supported_band *sband)
{
        unsigned int i;

        if (!sband)
                return;

        for (i = 0; i < sband->n_channels; i++)
                handle_channel(wiphy, initiator, &sband->channels[i]);
}

static bool reg_request_cell_base(struct regulatory_request *request)
{
        if (request->initiator != NL80211_REGDOM_SET_BY_USER)
                return false;
        return request->user_reg_hint_type == NL80211_USER_REG_HINT_CELL_BASE;
}

static bool reg_request_indoor(struct regulatory_request *request)
{
        if (request->initiator != NL80211_REGDOM_SET_BY_USER)
                return false;
        return request->user_reg_hint_type == NL80211_USER_REG_HINT_INDOOR;
}

bool reg_last_request_cell_base(void)
{
        return reg_request_cell_base(get_last_request());
}

#ifdef CONFIG_CFG80211_REG_CELLULAR_HINTS
/* Core specific check */
static enum reg_request_treatment
reg_ignore_cell_hint(struct regulatory_request *pending_request)
{
        struct regulatory_request *lr = get_last_request();

        if (!reg_num_devs_support_basehint)
                return REG_REQ_IGNORE;

        if (reg_request_cell_base(lr) &&
            !regdom_changes(pending_request->alpha2))
                return REG_REQ_ALREADY_SET;

        return REG_REQ_OK;
}

/* Device specific check */
static bool reg_dev_ignore_cell_hint(struct wiphy *wiphy)
{
        return !(wiphy->features & NL80211_FEATURE_CELL_BASE_REG_HINTS);
}
#else
static int reg_ignore_cell_hint(struct regulatory_request *pending_request)
{
        return REG_REQ_IGNORE;
}

static bool reg_dev_ignore_cell_hint(struct wiphy *wiphy)
{
        return true;
}
#endif

static bool wiphy_strict_alpha2_regd(struct wiphy *wiphy)
{
        if (wiphy->regulatory_flags & REGULATORY_STRICT_REG &&
            !(wiphy->regulatory_flags & REGULATORY_CUSTOM_REG))
                return true;
        return false;
}

static bool ignore_reg_update(struct wiphy *wiphy,
                              enum nl80211_reg_initiator initiator)
{
        struct regulatory_request *lr = get_last_request();

        if (!lr) {
                REG_DBG_PRINT("Ignoring regulatory request set by %s "
                              "since last_request is not set\n",
                              reg_initiator_name(initiator));
                return true;
        }

        if (initiator == NL80211_REGDOM_SET_BY_CORE &&
            wiphy->regulatory_flags & REGULATORY_CUSTOM_REG) {
                REG_DBG_PRINT("Ignoring regulatory request set by %s "
                              "since the driver uses its own custom "
                              "regulatory domain\n",
                              reg_initiator_name(initiator));
                return true;
        }

        /*
         * wiphy->regd will be set once the device has its own
         * desired regulatory domain set
         */
        if (wiphy_strict_alpha2_regd(wiphy) && !wiphy->regd &&
            initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&
            !is_world_regdom(lr->alpha2)) {
                REG_DBG_PRINT("Ignoring regulatory request set by %s "
                              "since the driver requires its own regulatory "
                              "domain to be set first\n",
                              reg_initiator_name(initiator));
                return true;
        }

        if (reg_request_cell_base(lr))
                return reg_dev_ignore_cell_hint(wiphy);

        return false;
}

static bool reg_is_world_roaming(struct wiphy *wiphy)
{
        const struct ieee80211_regdomain *cr = get_cfg80211_regdom();
        const struct ieee80211_regdomain *wr = get_wiphy_regdom(wiphy);
        struct regulatory_request *lr = get_last_request();

        if (is_world_regdom(cr->alpha2) || (wr && is_world_regdom(wr->alpha2)))
                return true;

        if (lr && lr->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&
            wiphy->regulatory_flags & REGULATORY_CUSTOM_REG)
                return true;

        return false;
}

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;

        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 (!reg_is_world_roaming(wiphy))
                return;

        if (wiphy->regulatory_flags & REGULATORY_DISABLE_BEACON_HINTS)
                return;

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

        if (chan->flags & IEEE80211_CHAN_NO_IR) {
                chan->flags &= ~IEEE80211_CHAN_NO_IR;
                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;

        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;

        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);
        }
}

/* 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;
        wiphy_update_beacon_reg(wiphy);
}

static bool is_ht40_allowed(struct ieee80211_channel *chan)
{
        if (!chan)
                return false;
        if (chan->flags & IEEE80211_CHAN_DISABLED)
                return false;
        /* This would happen when regulatory rules disallow HT40 completely */
        if ((chan->flags & IEEE80211_CHAN_NO_HT40) == IEEE80211_CHAN_NO_HT40)
                return false;
        return true;
}

static void reg_process_ht_flags_channel(struct wiphy *wiphy,
                                         struct ieee80211_channel *channel)
{
        struct ieee80211_supported_band *sband = wiphy->bands[channel->band];
        struct ieee80211_channel *channel_before = NULL, *channel_after = NULL;
        unsigned int i;

        if (!is_ht40_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_allowed(channel_before))
                channel->flags |= IEEE80211_CHAN_NO_HT40MINUS;
        else
                channel->flags &= ~IEEE80211_CHAN_NO_HT40MINUS;

        if (!is_ht40_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,
                                      struct ieee80211_supported_band *sband)
{
        unsigned int i;

        if (!sband)
                return;

        for (i = 0; i < sband->n_channels; i++)
                reg_process_ht_flags_channel(wiphy, &sband->channels[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++)
                reg_process_ht_flags_band(wiphy, wiphy->bands[band]);
}

static void reg_call_notifier(struct wiphy *wiphy,
                              struct regulatory_request *request)
{
        if (wiphy->reg_notifier)
                wiphy->reg_notifier(wiphy, request);
}

static bool reg_wdev_chan_valid(struct wiphy *wiphy, struct wireless_dev *wdev)
{
        struct ieee80211_channel *ch;
        struct cfg80211_chan_def chandef;
        struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
        bool ret = true;

        wdev_lock(wdev);

        if (!wdev->netdev || !netif_running(wdev->netdev))
                goto out;

        switch (wdev->iftype) {
        case NL80211_IFTYPE_AP:
        case NL80211_IFTYPE_P2P_GO:
                if (!wdev->beacon_interval)
                        goto out;

                ret = cfg80211_reg_can_beacon(wiphy,
                                              &wdev->chandef, wdev->iftype);
                break;
        case NL80211_IFTYPE_ADHOC:
                if (!wdev->ssid_len)
                        goto out;

                ret = cfg80211_reg_can_beacon(wiphy,
                                              &wdev->chandef, wdev->iftype);
                break;
        case NL80211_IFTYPE_STATION:
        case NL80211_IFTYPE_P2P_CLIENT:
                if (!wdev->current_bss ||
                    !wdev->current_bss->pub.channel)
                        goto out;

                ch = wdev->current_bss->pub.channel;
                if (rdev->ops->get_channel &&
                    !rdev_get_channel(rdev, wdev, &chandef))
                        ret = cfg80211_chandef_usable(wiphy, &chandef,
                                                      IEEE80211_CHAN_DISABLED);
                else
                        ret = !(ch->flags & IEEE80211_CHAN_DISABLED);
                break;
        case NL80211_IFTYPE_MONITOR:
        case NL80211_IFTYPE_AP_VLAN:
        case NL80211_IFTYPE_P2P_DEVICE:
                /* no enforcement required */
                break;
        default:
                /* others not implemented for now */
                WARN_ON(1);
                break;
        }

out:
        wdev_unlock(wdev);
        return ret;
}

static void reg_leave_invalid_chans(struct wiphy *wiphy)
{
        struct wireless_dev *wdev;
        struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);

        ASSERT_RTNL();

        list_for_each_entry(wdev, &rdev->wdev_list, list)
                if (!reg_wdev_chan_valid(wiphy, wdev))
                        cfg80211_leave(rdev, wdev);
}

static void reg_check_chans_work(struct work_struct *work)
{
        struct cfg80211_registered_device *rdev;

        REG_DBG_PRINT("Verifying active interfaces after reg change\n");
        rtnl_lock();

        list_for_each_entry(rdev, &cfg80211_rdev_list, list)
                if (!(rdev->wiphy.regulatory_flags &
                      REGULATORY_IGNORE_STALE_KICKOFF))
                        reg_leave_invalid_chans(&rdev->wiphy);

        rtnl_unlock();
}

static void reg_check_channels(void)
{
        /*
         * Give usermode a chance to do something nicer (move to another
         * channel, orderly disconnection), before forcing a disconnection.
         */
        mod_delayed_work(system_power_efficient_wq,
                         &reg_check_chans,
                         msecs_to_jiffies(REG_ENFORCE_GRACE_MS));
}

static void wiphy_update_regulatory(struct wiphy *wiphy,
                                    enum nl80211_reg_initiator initiator)
{
        enum ieee80211_band band;
        struct regulatory_request *lr = get_last_request();

        if (ignore_reg_update(wiphy, initiator)) {
                /*
                 * Regulatory updates set by CORE are ignored for custom
                 * regulatory cards. Let us notify the changes to the driver,
                 * as some drivers used this to restore its orig_* reg domain.
                 */
                if (initiator == NL80211_REGDOM_SET_BY_CORE &&
                    wiphy->regulatory_flags & REGULATORY_CUSTOM_REG)
                        reg_call_notifier(wiphy, lr);
                return;
        }

        lr->dfs_region = get_cfg80211_regdom()->dfs_region;

        for (band = 0; band < IEEE80211_NUM_BANDS; band++)
                handle_band(wiphy, initiator, wiphy->bands[band]);

        reg_process_beacons(wiphy);
        reg_process_ht_flags(wiphy);
        reg_call_notifier(wiphy, lr);
}

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

        ASSERT_RTNL();

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

        reg_check_channels();
}

static void handle_channel_custom(struct wiphy *wiphy,
                                  struct ieee80211_channel *chan,
                                  const struct ieee80211_regdomain *regd)
{
        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;
        u32 max_bandwidth_khz;

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

        if (IS_ERR(reg_rule)) {
                REG_DBG_PRINT("Disabling freq %d MHz as custom regd has no rule that fits it\n",
                              chan->center_freq);
                chan->orig_flags |= IEEE80211_CHAN_DISABLED;
                chan->flags = chan->orig_flags;
                return;
        }

        chan_reg_rule_print_dbg(regd, chan, reg_rule);

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

        max_bandwidth_khz = freq_range->max_bandwidth_khz;
        /* Check if auto calculation requested */
        if (reg_rule->flags & NL80211_RRF_AUTO_BW)
                max_bandwidth_khz = reg_get_max_bandwidth(regd, reg_rule);

        if (max_bandwidth_khz < MHZ_TO_KHZ(40))
                bw_flags = IEEE80211_CHAN_NO_HT40;
        if (max_bandwidth_khz < MHZ_TO_KHZ(80))
                bw_flags |= IEEE80211_CHAN_NO_80MHZ;
        if (max_bandwidth_khz < MHZ_TO_KHZ(160))
                bw_flags |= IEEE80211_CHAN_NO_160MHZ;

        chan->dfs_state_entered = jiffies;
        chan->dfs_state = NL80211_DFS_USABLE;

        chan->beacon_found = false;
        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_reg_power = chan->max_power =
                (int) MBM_TO_DBM(power_rule->max_eirp);

        if (chan->flags & IEEE80211_CHAN_RADAR) {
                if (reg_rule->dfs_cac_ms)
                        chan->dfs_cac_ms = reg_rule->dfs_cac_ms;
                else
                        chan->dfs_cac_ms = IEEE80211_DFS_MIN_CAC_TIME_MS;
        }

        chan->max_power = chan->max_reg_power;
}

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

        if (!sband)
                return;

        for (i = 0; i < sband->n_channels; i++)
                handle_channel_custom(wiphy, &sband->channels[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;

        WARN(!(wiphy->regulatory_flags & REGULATORY_CUSTOM_REG),
             "wiphy should have REGULATORY_CUSTOM_REG\n");
        wiphy->regulatory_flags |= REGULATORY_CUSTOM_REG;

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

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

static void reg_set_request_processed(void)
{
        bool need_more_processing = false;
        struct regulatory_request *lr = get_last_request();

        lr->processed = true;

        spin_lock(&reg_requests_lock);
        if (!list_empty(&reg_requests_list))
                need_more_processing = true;
        spin_unlock(&reg_requests_lock);

        if (lr->initiator == NL80211_REGDOM_SET_BY_USER)
                cancel_delayed_work(&reg_timeout);

        if (need_more_processing)
                schedule_work(&reg_work);
}

/**
 * reg_process_hint_core - process core regulatory requests
 * @pending_request: a pending core regulatory request
 *
 * The wireless subsystem can use this function to process
 * a regulatory request issued by the regulatory core.
 *
 * Returns one of the different reg request treatment values.
 */
static enum reg_request_treatment
reg_process_hint_core(struct regulatory_request *core_request)
{

        core_request->intersect = false;
        core_request->processed = false;

        reg_update_last_request(core_request);

        return reg_call_crda(core_request);
}

static enum reg_request_treatment
__reg_process_hint_user(struct regulatory_request *user_request)
{
        struct regulatory_request *lr = get_last_request();

        if (reg_request_indoor(user_request)) {
                reg_is_indoor = true;
                return REG_REQ_USER_HINT_HANDLED;
        }

        if (reg_request_cell_base(user_request))
                return reg_ignore_cell_hint(user_request);

        if (reg_request_cell_base(lr))
                return REG_REQ_IGNORE;

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

        if (!regdom_changes(user_request->alpha2))
                return REG_REQ_ALREADY_SET;

        return REG_REQ_OK;
}

/**
 * reg_process_hint_user - process user regulatory requests
 * @user_request: a pending user regulatory request
 *
 * The wireless subsystem can use this function to process
 * a regulatory request initiated by userspace.
 *
 * Returns one of the different reg request treatment values.
 */
static enum reg_request_treatment
reg_process_hint_user(struct regulatory_request *user_request)
{
        enum reg_request_treatment treatment;

        treatment = __reg_process_hint_user(user_request);
        if (treatment == REG_REQ_IGNORE ||
            treatment == REG_REQ_ALREADY_SET ||
            treatment == REG_REQ_USER_HINT_HANDLED) {
                reg_free_request(user_request);
                return treatment;
        }

        user_request->intersect = treatment == REG_REQ_INTERSECT;
        user_request->processed = false;

        reg_update_last_request(user_request);

        user_alpha2[0] = user_request->alpha2[0];
        user_alpha2[1] = user_request->alpha2[1];

        return reg_call_crda(user_request);
}

static enum reg_request_treatment
__reg_process_hint_driver(struct regulatory_request *driver_request)
{
        struct regulatory_request *lr = get_last_request();

        if (lr->initiator == NL80211_REGDOM_SET_BY_CORE) {
                if (regdom_changes(driver_request->alpha2))
                        return REG_REQ_OK;
                return REG_REQ_ALREADY_SET;
        }

        /*
         * 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 (lr->initiator == NL80211_REGDOM_SET_BY_DRIVER &&
            !regdom_changes(driver_request->alpha2))
                return REG_REQ_ALREADY_SET;

        return REG_REQ_INTERSECT;
}

/**
 * reg_process_hint_driver - process driver regulatory requests
 * @driver_request: a pending driver regulatory request
 *
 * The wireless subsystem can use this function to process
 * a regulatory request issued by an 802.11 driver.
 *
 * Returns one of the different reg request treatment values.
 */
static enum reg_request_treatment
reg_process_hint_driver(struct wiphy *wiphy,
                        struct regulatory_request *driver_request)
{
        const struct ieee80211_regdomain *regd, *tmp;
        enum reg_request_treatment treatment;

        treatment = __reg_process_hint_driver(driver_request);

        switch (treatment) {
        case REG_REQ_OK:
                break;
        case REG_REQ_IGNORE:
        case REG_REQ_USER_HINT_HANDLED:
                reg_free_request(driver_request);
                return treatment;
        case REG_REQ_INTERSECT:
                /* fall through */
        case REG_REQ_ALREADY_SET:
                regd = reg_copy_regd(get_cfg80211_regdom());
                if (IS_ERR(regd)) {
                        reg_free_request(driver_request);
                        return REG_REQ_IGNORE;
                }

                tmp = get_wiphy_regdom(wiphy);
                rcu_assign_pointer(wiphy->regd, regd);
                rcu_free_regdom(tmp);
        }


        driver_request->intersect = treatment == REG_REQ_INTERSECT;
        driver_request->processed = false;

        reg_update_last_request(driver_request);

        /*
         * 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 (treatment == REG_REQ_ALREADY_SET) {
                nl80211_send_reg_change_event(driver_request);
                reg_set_request_processed();
                return treatment;
        }

        return reg_call_crda(driver_request);
}

static enum reg_request_treatment
__reg_process_hint_country_ie(struct wiphy *wiphy,
                              struct regulatory_request *country_ie_request)
{
        struct wiphy *last_wiphy = NULL;
        struct regulatory_request *lr = get_last_request();

        if (reg_request_cell_base(lr)) {
                /* Trust a Cell base station over the AP's country IE */
                if (regdom_changes(country_ie_request->alpha2))
                        return REG_REQ_IGNORE;
                return REG_REQ_ALREADY_SET;
        } else {
                if (wiphy->regulatory_flags & REGULATORY_COUNTRY_IE_IGNORE)
                        return REG_REQ_IGNORE;
        }

        if (unlikely(!is_an_alpha2(country_ie_request->alpha2)))
                return -EINVAL;

        if (lr->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE)
                return REG_REQ_OK;

        last_wiphy = wiphy_idx_to_wiphy(lr->wiphy_idx);

        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(country_ie_request->alpha2))
                        return REG_REQ_IGNORE;
                return REG_REQ_ALREADY_SET;
        }

        if (regdom_changes(country_ie_request->alpha2))
                return REG_REQ_OK;
        return REG_REQ_ALREADY_SET;
}

/**
 * reg_process_hint_country_ie - process regulatory requests from country IEs
 * @country_ie_request: a regulatory request from a country IE
 *
 * The wireless subsystem can use this function to process
 * a regulatory request issued by a country Information Element.
 *
 * Returns one of the different reg request treatment values.
 */
static enum reg_request_treatment
reg_process_hint_country_ie(struct wiphy *wiphy,
                            struct regulatory_request *country_ie_request)
{
        enum reg_request_treatment treatment;

        treatment = __reg_process_hint_country_ie(wiphy, country_ie_request);

        switch (treatment) {
        case REG_REQ_OK:
                break;
        case REG_REQ_IGNORE:
        case REG_REQ_USER_HINT_HANDLED:
                /* fall through */
        case REG_REQ_ALREADY_SET:
                reg_free_request(country_ie_request);
                return treatment;
        case REG_REQ_INTERSECT:
                reg_free_request(country_ie_request);
                /*
                 * This doesn't happen yet, not sure we
                 * ever want to support it for this case.
                 */
                WARN_ONCE(1, "Unexpected intersection for country IEs");
                return REG_REQ_IGNORE;
        }

        country_ie_request->intersect = false;
        country_ie_request->processed = false;

        reg_update_last_request(country_ie_request);

        return reg_call_crda(country_ie_request);
}

/* This processes *all* regulatory hints */
static void reg_process_hint(struct regulatory_request *reg_request)
{
        struct wiphy *wiphy = NULL;
        enum reg_request_treatment treatment;

        if (reg_request->wiphy_idx != WIPHY_IDX_INVALID)
                wiphy = wiphy_idx_to_wiphy(reg_request->wiphy_idx);

        switch (reg_request->initiator) {
        case NL80211_REGDOM_SET_BY_CORE:
                reg_process_hint_core(reg_request);
                return;
        case NL80211_REGDOM_SET_BY_USER:
                treatment = reg_process_hint_user(reg_request);
                if (treatment == REG_REQ_IGNORE ||
                    treatment == REG_REQ_ALREADY_SET ||
                    treatment == REG_REQ_USER_HINT_HANDLED)
                        return;
                queue_delayed_work(system_power_efficient_wq,
                                   &reg_timeout, msecs_to_jiffies(3142));
                return;
        case NL80211_REGDOM_SET_BY_DRIVER:
                if (!wiphy)
                        goto out_free;
                treatment = reg_process_hint_driver(wiphy, reg_request);
                break;
        case NL80211_REGDOM_SET_BY_COUNTRY_IE:
                if (!wiphy)
                        goto out_free;
                treatment = reg_process_hint_country_ie(wiphy, reg_request);
                break;
        default:
                WARN(1, "invalid initiator %d\n", reg_request->initiator);
                goto out_free;
        }

        /* This is required so that the orig_* parameters are saved */
        if (treatment == REG_REQ_ALREADY_SET && wiphy &&
            wiphy->regulatory_flags & REGULATORY_STRICT_REG) {
                wiphy_update_regulatory(wiphy, reg_request->initiator);
                reg_check_channels();
        }

        return;

out_free:
        reg_free_request(reg_request);
}

/*
 * Processes regulatory hints, this is all the NL80211_REGDOM_SET_BY_*
 * Regulatory hints come on a first come first serve basis and we
 * must process each one atomically.
 */
static void reg_process_pending_hints(void)
{
        struct regulatory_request *reg_request, *lr;

        lr = get_last_request();

        /* When last_request->processed becomes true this will be rescheduled */
        if (lr && !lr->processed) {
                reg_process_hint(lr);
                return;
        }

        spin_lock(&reg_requests_lock);

        if (list_empty(&reg_requests_list)) {
                spin_unlock(&reg_requests_lock);
                return;
        }

        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);
}

/* 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;

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

        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);
}

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

static void queue_regulatory_request(struct regulatory_request *request)
{
        request->alpha2[0] = toupper(request->alpha2[0]);
        request->alpha2[1] = toupper(request->alpha2[1]);

        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;

        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);

        return 0;
}

/* User hints */
int regulatory_hint_user(const char *alpha2,
                         enum nl80211_user_reg_hint_type user_reg_hint_type)
{
        struct regulatory_request *request;

        if (WARN_ON(!alpha2))
                return -EINVAL;

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

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

        queue_regulatory_request(request);

        return 0;
}

int regulatory_hint_indoor_user(void)
{
        struct regulatory_request *request;

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

        request->wiphy_idx = WIPHY_IDX_INVALID;
        request->initiator = NL80211_REGDOM_SET_BY_USER;
        request->user_reg_hint_type = NL80211_USER_REG_HINT_INDOOR;
        queue_regulatory_request(request);

        return 0;
}

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

        if (WARN_ON(!alpha2 || !wiphy))
                return -EINVAL;

        wiphy->regulatory_flags &= ~REGULATORY_CUSTOM_REG;

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

        request->wiphy_idx = get_wiphy_idx(wiphy);

        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);

void regulatory_hint_country_ie(struct wiphy *wiphy, enum ieee80211_band band,
                                const u8 *country_ie, u8 country_ie_len)
{
        char alpha2[2];
        enum environment_cap env = ENVIRON_ANY;
        struct regulatory_request *request = NULL, *lr;

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

        if (country_ie_len < IEEE80211_COUNTRY_IE_MIN_LEN)
                return;

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

        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;

        rcu_read_lock();
        lr = get_last_request();

        if (unlikely(!lr))
                goto out;

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

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

        queue_regulatory_request(request);
        request = NULL;
out:
        kfree(request);
        rcu_read_unlock();
}

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("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("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("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("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("Restoring regulatory settings\n");
}

static void restore_custom_reg_settings(struct wiphy *wiphy)
{
        struct ieee80211_supported_band *sband;
        enum ieee80211_band band;
        struct ieee80211_channel *chan;
        int i;

        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                sband = wiphy->bands[band];
                if (!sband)
                        continue;
                for (i = 0; i < sband->n_channels; i++) {
                        chan = &sband->channels[i];
                        chan->flags = chan->orig_flags;
                        chan->max_antenna_gain = chan->orig_mag;
                        chan->max_power = chan->orig_mpwr;
                        chan->beacon_found = false;
                }
        }
}

/*
 * 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];
        char world_alpha2[2];
        struct reg_beacon *reg_beacon, *btmp;
        struct regulatory_request *reg_request, *tmp;
        LIST_HEAD(tmp_reg_req_list);
        struct cfg80211_registered_device *rdev;

        ASSERT_RTNL();

        reg_is_indoor = false;

        reset_regdomains(true, &world_regdom);
        restore_alpha2(alpha2, reset_user);

        /*
         * If there's any pending requests we simply
         * stash them to a temporary pending queue and
         * add then after we've restored regulatory
         * settings.
         */
        spin_lock(&reg_requests_lock);
        list_for_each_entry_safe(reg_request, tmp, &reg_requests_list, list) {
                if (reg_request->initiator != NL80211_REGDOM_SET_BY_USER)
                        continue;
                list_move_tail(&reg_request->list, &tmp_reg_req_list);
        }
        spin_unlock(&reg_requests_lock);

        /* Clear beacon hints */
        spin_lock_bh(&reg_pending_beacons_lock);
        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);

        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 */
        world_alpha2[0] = cfg80211_world_regdom->alpha2[0];
        world_alpha2[1] = cfg80211_world_regdom->alpha2[1];

        list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
                if (rdev->wiphy.regulatory_flags & REGULATORY_CUSTOM_REG)
                        restore_custom_reg_settings(&rdev->wiphy);
        }

        regulatory_hint_core(world_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, NL80211_USER_REG_HINT_USER);

        spin_lock(&reg_requests_lock);
        list_splice_tail_init(&tmp_reg_req_list, &reg_requests_list);
        spin_unlock(&reg_requests_lock);

        REG_DBG_PRINT("Kicking the queue\n");

        schedule_work(&reg_work);
}

void regulatory_hint_disconnect(void)
{
        REG_DBG_PRINT("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, IEEE80211_BAND_2GHZ) ||
            freq == ieee80211_channel_to_frequency(13, IEEE80211_BAND_2GHZ) ||
            freq == ieee80211_channel_to_frequency(14, IEEE80211_BAND_2GHZ))
                return true;
        return false;
}

static bool pending_reg_beacon(struct ieee80211_channel *beacon_chan)
{
        struct reg_beacon *pending_beacon;

        list_for_each_entry(pending_beacon, &reg_pending_beacons, list)
                if (beacon_chan->center_freq ==
                    pending_beacon->chan.center_freq)
                        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;
        bool processing;

        if (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;

        spin_lock_bh(&reg_pending_beacons_lock);
        processing = pending_reg_beacon(beacon_chan);
        spin_unlock_bh(&reg_pending_beacons_lock);

        if (processing)
                return 0;

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

        REG_DBG_PRINT("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;
        char bw[32], cac_time[32];

        pr_info("  (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)\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;

                if (reg_rule->flags & NL80211_RRF_AUTO_BW)
                        snprintf(bw, sizeof(bw), "%d KHz, %d KHz AUTO",
                                 freq_range->max_bandwidth_khz,
                                 reg_get_max_bandwidth(rd, reg_rule));
                else
                        snprintf(bw, sizeof(bw), "%d KHz",
                                 freq_range->max_bandwidth_khz);

                if (reg_rule->flags & NL80211_RRF_DFS)
                        scnprintf(cac_time, sizeof(cac_time), "%u s",
                                  reg_rule->dfs_cac_ms/1000);
                else
                        scnprintf(cac_time, sizeof(cac_time), "N/A");


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

bool reg_supported_dfs_region(enum nl80211_dfs_regions dfs_region)
{
        switch (dfs_region) {
        case NL80211_DFS_UNSET:
        case NL80211_DFS_FCC:
        case NL80211_DFS_ETSI:
        case NL80211_DFS_JP:
                return true;
        default:
                REG_DBG_PRINT("Ignoring uknown DFS master region: %d\n",
                              dfs_region);
                return false;
        }
}

static void print_regdomain(const struct ieee80211_regdomain *rd)
{
        struct regulatory_request *lr = get_last_request();

        if (is_intersected_alpha2(rd->alpha2)) {
                if (lr->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE) {
                        struct cfg80211_registered_device *rdev;
                        rdev = cfg80211_rdev_by_wiphy_idx(lr->wiphy_idx);
                        if (rdev) {
                                pr_info("Current regulatory domain updated by AP to: %c%c\n",
                                        rdev->country_ie_alpha2[0],
                                        rdev->country_ie_alpha2[1]);
                        } else
                                pr_info("Current regulatory domain intersected:\n");
                } else
                        pr_info("Current regulatory domain intersected:\n");
        } else if (is_world_regdom(rd->alpha2)) {
                pr_info("World regulatory domain updated:\n");
        } else {
                if (is_unknown_alpha2(rd->alpha2))
                        pr_info("Regulatory domain changed to driver built-in settings (unknown country)\n");
                else {
                        if (reg_request_cell_base(lr))
                                pr_info("Regulatory domain changed to country: %c%c by Cell Station\n",
                                        rd->alpha2[0], rd->alpha2[1]);
                        else
                                pr_info("Regulatory domain changed to country: %c%c\n",
                                        rd->alpha2[0], rd->alpha2[1]);
                }
        }

        pr_info(" DFS Master region: %s", reg_dfs_region_str(rd->dfs_region));
        print_rd_rules(rd);
}

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

static int reg_set_rd_core(const struct ieee80211_regdomain *rd)
{
        if (!is_world_regdom(rd->alpha2))
                return -EINVAL;
        update_world_regdomain(rd);
        return 0;
}

static int reg_set_rd_user(const struct ieee80211_regdomain *rd,
                           struct regulatory_request *user_request)
{
        const struct ieee80211_regdomain *intersected_rd = NULL;

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

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

        if (!user_request->intersect) {
                reset_regdomains(false, rd);
                return 0;
        }

        intersected_rd = regdom_intersect(rd, get_cfg80211_regdom());
        if (!intersected_rd)
                return -EINVAL;

        kfree(rd);
        rd = NULL;
        reset_regdomains(false, intersected_rd);

        return 0;
}

static int reg_set_rd_driver(const struct ieee80211_regdomain *rd,
                             struct regulatory_request *driver_request)
{
        const struct ieee80211_regdomain *regd;
        const struct ieee80211_regdomain *intersected_rd = NULL;
        const struct ieee80211_regdomain *tmp;
        struct wiphy *request_wiphy;

        if (is_world_regdom(rd->alpha2))
                return -EINVAL;

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

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

        request_wiphy = wiphy_idx_to_wiphy(driver_request->wiphy_idx);
        if (!request_wiphy) {
                queue_delayed_work(system_power_efficient_wq,
                                   &reg_timeout, 0);
                return -ENODEV;
        }

        if (!driver_request->intersect) {
                if (request_wiphy->regd)
                        return -EALREADY;

                regd = reg_copy_regd(rd);
                if (IS_ERR(regd))
                        return PTR_ERR(regd);

                rcu_assign_pointer(request_wiphy->regd, regd);
                reset_regdomains(false, rd);
                return 0;
        }

        intersected_rd = regdom_intersect(rd, get_cfg80211_regdom());
        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
         */
        tmp = get_wiphy_regdom(request_wiphy);
        rcu_assign_pointer(request_wiphy->regd, rd);
        rcu_free_regdom(tmp);

        rd = NULL;

        reset_regdomains(false, intersected_rd);

        return 0;
}

static int reg_set_rd_country_ie(const struct ieee80211_regdomain *rd,
                                 struct regulatory_request *country_ie_request)
{
        struct wiphy *request_wiphy;

        if (!is_alpha2_set(rd->alpha2) && !is_an_alpha2(rd->alpha2) &&
            !is_unknown_alpha2(rd->alpha2))
                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 (!is_valid_rd(rd)) {
                pr_err("Invalid regulatory domain detected:\n");
                print_regdomain_info(rd);
                return -EINVAL;
        }

        request_wiphy = wiphy_idx_to_wiphy(country_ie_request->wiphy_idx);
        if (!request_wiphy) {
                queue_delayed_work(system_power_efficient_wq,
                                   &reg_timeout, 0);
                return -ENODEV;
        }

        if (country_ie_request->intersect)
                return -EINVAL;

        reset_regdomains(false, 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.
 */
int set_regdom(const struct ieee80211_regdomain *rd)
{
        struct regulatory_request *lr;
        bool user_reset = false;
        int r;

        if (!reg_is_valid_request(rd->alpha2)) {
                kfree(rd);
                return -EINVAL;
        }

        lr = get_last_request();

        /* Note that this doesn't update the wiphys, this is done below */
        switch (lr->initiator) {
        case NL80211_REGDOM_SET_BY_CORE:
                r = reg_set_rd_core(rd);
                break;
        case NL80211_REGDOM_SET_BY_USER:
                r = reg_set_rd_user(rd, lr);
                user_reset = true;
                break;
        case NL80211_REGDOM_SET_BY_DRIVER:
                r = reg_set_rd_driver(rd, lr);
                break;
        case NL80211_REGDOM_SET_BY_COUNTRY_IE:
                r = reg_set_rd_country_ie(rd, lr);
                break;
        default:
                WARN(1, "invalid initiator %d\n", lr->initiator);
                return -EINVAL;
        }

        if (r) {
                switch (r) {
                case -EALREADY:
                        reg_set_request_processed();
                        break;
                default:
                        /* Back to world regulatory in case of errors */
                        restore_regulatory_settings(user_reset);
                }

                kfree(rd);
                return r;
        }

        /* This would make this whole thing pointless */
        if (WARN_ON(!lr->intersect && rd != get_cfg80211_regdom()))
                return -EINVAL;

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

        print_regdomain(get_cfg80211_regdom());

        nl80211_send_reg_change_event(lr);

        reg_set_request_processed();

        return 0;
}

void wiphy_regulatory_register(struct wiphy *wiphy)
{
        struct regulatory_request *lr;

        if (!reg_dev_ignore_cell_hint(wiphy))
                reg_num_devs_support_basehint++;

        lr = get_last_request();
        wiphy_update_regulatory(wiphy, lr->initiator);
}

void wiphy_regulatory_deregister(struct wiphy *wiphy)
{
        struct wiphy *request_wiphy = NULL;
        struct regulatory_request *lr;

        lr = get_last_request();

        if (!reg_dev_ignore_cell_hint(wiphy))
                reg_num_devs_support_basehint--;

        rcu_free_regdom(get_wiphy_regdom(wiphy));
        RCU_INIT_POINTER(wiphy->regd, NULL);

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

        if (!request_wiphy || request_wiphy != wiphy)
                return;

        lr->wiphy_idx = WIPHY_IDX_INVALID;
        lr->country_ie_env = ENVIRON_ANY;
}

static void reg_timeout_work(struct work_struct *work)
{
        REG_DBG_PRINT("Timeout while waiting for CRDA to reply, restoring regulatory settings\n");
        rtnl_lock();
        restore_regulatory_settings(true);
        rtnl_unlock();
}

/*
 * See http://www.fcc.gov/document/5-ghz-unlicensed-spectrum-unii, for
 * UNII band definitions
 */
int cfg80211_get_unii(int freq)
{
        /* UNII-1 */
        if (freq >= 5150 && freq <= 5250)
                return 0;

        /* UNII-2A */
        if (freq > 5250 && freq <= 5350)
                return 1;

        /* UNII-2B */
        if (freq > 5350 && freq <= 5470)
                return 2;

        /* UNII-2C */
        if (freq > 5470 && freq <= 5725)
                return 3;

        /* UNII-3 */
        if (freq > 5725 && freq <= 5825)
                return 4;

        return -EINVAL;
}

bool regulatory_indoor_allowed(void)
{
        return reg_is_indoor;
}

int __init 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);

        reg_regdb_size_check();

        rcu_assign_pointer(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_world_regdom->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.
                 */
                pr_err("kobject_uevent_env() was unable to call CRDA during init\n");
        }

        /*
         * 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,
                                     NL80211_USER_REG_HINT_USER);

        return 0;
}

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

        cancel_work_sync(&reg_work);
        cancel_delayed_work_sync(&reg_timeout);
        cancel_delayed_work_sync(&reg_check_chans);

        /* Lock to suppress warnings */
        rtnl_lock();
        reset_regdomains(true, NULL);
        rtnl_unlock();

        dev_set_uevent_suppress(&reg_pdev->dev, true);

        platform_device_unregister(reg_pdev);

        list_for_each_entry_safe(reg_beacon, btmp, &reg_pending_beacons, list) {
                list_del(&reg_beacon->list);
                kfree(reg_beacon);
        }

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

        list_for_each_entry_safe(reg_request, tmp, &reg_requests_list, list) {
                list_del(&reg_request->list);
                kfree(reg_request);
        }
}