/*
   * Copyright 2002-2005, Instant802 Networks, Inc.
   * Copyright 2005-2006, Devicescape Software, Inc.
   * Copyright 2007	Johannes Berg <johannes@sipsolutions.net>

   * Copyright 2008	Luis R. Rodriguez <lrodriguz@atheros.com>

   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */

  /**
   * DOC: Wireless regulatory infrastructure

   *
   * The usual implementation is for a driver to read a device EEPROM to
   * determine which regulatory domain it should be operating under, then
   * looking up the allowable channels in a driver-local table and finally
   * registering those channels in the wiphy structure.
   *

   * Another set of compliance enforcement is for drivers to use their
   * own compliance limits which can be stored on the EEPROM. The host
   * driver or firmware may ensure these are used.
   *
   * In addition to all this we provide an extra layer of regulatory
   * conformance. For drivers which do not have any regulatory
   * information CRDA provides the complete regulatory solution.
   * For others it provides a community effort on further restrictions
   * to enhance compliance.
   *
   * Note: When number of rules --> infinity we will not be able to
   * index on alpha2 any more, instead we'll probably have to
   * rely on some SHA1 checksum of the regdomain for example.
   *

   */

  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/kernel.h>

  #include <linux/slab.h>

  #include <linux/list.h>
  #include <linux/random.h>

  #include <linux/ctype.h>

  #include <linux/nl80211.h>
  #include <linux/platform_device.h>

  #include <net/cfg80211.h>

  #include "core.h"

  #include "reg.h"

  #include "regdb.h"

  #include "nl80211.h"

  #ifdef CONFIG_CFG80211_REG_DEBUG

  #define REG_DBG_PRINT(format, args...) \

  	do { \

  		printk(KERN_DEBUG pr_fmt(format), ##args);	\

  	} while (0)
  #else

  #define REG_DBG_PRINT(args...)

  #endif

  /* Receipt of information from last regulatory request */

  static struct regulatory_request *last_request;

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

  /*
   * Central wireless core regulatory domains, we only need two,

   * the current one and a world regulatory domain in case we have no

   * information to give us an alpha2
   */

  const struct ieee80211_regdomain *cfg80211_regdomain;

  /*

   * Protects static reg.c components:
   *     - cfg80211_world_regdom
   *     - cfg80211_regdom

   *     - last_request
   */

  static DEFINE_MUTEX(reg_mutex);

  
  static inline void assert_reg_lock(void)
  {
  	lockdep_assert_held(&reg_mutex);
  }

  /* Used to queue up regulatory hints */

  static LIST_HEAD(reg_requests_list);
  static spinlock_t reg_requests_lock;

  /* Used to queue up beacon hints for review */
  static LIST_HEAD(reg_pending_beacons);
  static spinlock_t reg_pending_beacons_lock;
  
  /* Used to keep track of processed beacon hints */
  static LIST_HEAD(reg_beacon_list);
  
  struct reg_beacon {
  	struct list_head list;
  	struct ieee80211_channel chan;
  };

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

  /* We keep a static world regulatory domain in case of the absence of CRDA */
  static const struct ieee80211_regdomain world_regdom = {

  	.n_reg_rules = 5,

  	.alpha2 =  "00",
  	.reg_rules = {

  		/* IEEE 802.11b/g, channels 1..11 */
  		REG_RULE(2412-10, 2462+10, 40, 6, 20, 0),

  		/* IEEE 802.11b/g, channels 12..13. No HT40
  		 * channel fits here. */
  		REG_RULE(2467-10, 2472+10, 20, 6, 20,

  			NL80211_RRF_PASSIVE_SCAN |
  			NL80211_RRF_NO_IBSS),

  		/* IEEE 802.11 channel 14 - Only JP enables
  		 * this and for 802.11b only */
  		REG_RULE(2484-10, 2484+10, 20, 6, 20,
  			NL80211_RRF_PASSIVE_SCAN |
  			NL80211_RRF_NO_IBSS |
  			NL80211_RRF_NO_OFDM),
  		/* IEEE 802.11a, channel 36..48 */

  		REG_RULE(5180-10, 5240+10, 40, 6, 20,

                          NL80211_RRF_PASSIVE_SCAN |
                          NL80211_RRF_NO_IBSS),

  
  		/* NB: 5260 MHz - 5700 MHz requies DFS */
  
  		/* IEEE 802.11a, channel 149..165 */

  		REG_RULE(5745-10, 5825+10, 40, 6, 20,

  			NL80211_RRF_PASSIVE_SCAN |
  			NL80211_RRF_NO_IBSS),

  	}
  };

  static const struct ieee80211_regdomain *cfg80211_world_regdom =
  	&world_regdom;

  static char *ieee80211_regdom = "00";

  static char user_alpha2[2];

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

  static void reset_regdomains(void)
  {

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

  
  	kfree(cfg80211_regdomain);
  	kfree(cfg80211_world_regdom);

  	cfg80211_world_regdom = &world_regdom;

  	cfg80211_regdomain = NULL;
  }

  /*
   * Dynamic world regulatory domain requested by the wireless
   * core upon initialization
   */

  static void update_world_regdomain(const struct ieee80211_regdomain *rd)

  {

  	BUG_ON(!last_request);

  
  	reset_regdomains();
  
  	cfg80211_world_regdom = rd;
  	cfg80211_regdomain = rd;
  }

  bool is_world_regdom(const char *alpha2)

  {
  	if (!alpha2)
  		return false;
  	if (alpha2[0] == '0' && alpha2[1] == '0')
  		return true;
  	return false;
  }

  static bool is_alpha2_set(const char *alpha2)

  {
  	if (!alpha2)
  		return false;
  	if (alpha2[0] != 0 && alpha2[1] != 0)
  		return true;
  	return false;
  }

  static bool is_unknown_alpha2(const char *alpha2)

  {
  	if (!alpha2)
  		return false;

  	/*
  	 * Special case where regulatory domain was built by driver
  	 * but a specific alpha2 cannot be determined
  	 */

  	if (alpha2[0] == '9' && alpha2[1] == '9')
  		return true;
  	return false;
  }

  static bool is_intersected_alpha2(const char *alpha2)
  {
  	if (!alpha2)
  		return false;

  	/*
  	 * Special case where regulatory domain is the

  	 * result of an intersection between two regulatory domain

  	 * structures
  	 */

  	if (alpha2[0] == '9' && alpha2[1] == '8')
  		return true;
  	return false;
  }

  static bool is_an_alpha2(const char *alpha2)

  {
  	if (!alpha2)
  		return false;

  	if (isalpha(alpha2[0]) && isalpha(alpha2[1]))

  		return true;
  	return false;
  }

  static bool alpha2_equal(const char *alpha2_x, const char *alpha2_y)

  {
  	if (!alpha2_x || !alpha2_y)
  		return false;
  	if (alpha2_x[0] == alpha2_y[0] &&
  		alpha2_x[1] == alpha2_y[1])
  		return true;
  	return false;
  }

  static bool regdom_changes(const char *alpha2)

  {

  	assert_cfg80211_lock();

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

  /*
   * The NL80211_REGDOM_SET_BY_USER regdom alpha2 is cached, this lets
   * you know if a valid regulatory hint with NL80211_REGDOM_SET_BY_USER
   * has ever been issued.
   */
  static bool is_user_regdom_saved(void)
  {
  	if (user_alpha2[0] == '9' && user_alpha2[1] == '7')
  		return false;
  
  	/* This would indicate a mistake on the design */
  	if (WARN((!is_world_regdom(user_alpha2) &&
  		  !is_an_alpha2(user_alpha2)),
  		 "Unexpected user alpha2: %c%c
  ",
  		 user_alpha2[0],
  	         user_alpha2[1]))
  		return false;
  
  	return true;
  }

  static int reg_copy_regd(const struct ieee80211_regdomain **dst_regd,
  			 const struct ieee80211_regdomain *src_regd)
  {
  	struct ieee80211_regdomain *regd;
  	int size_of_regd = 0;
  	unsigned int i;
  
  	size_of_regd = sizeof(struct ieee80211_regdomain) +
  	  ((src_regd->n_reg_rules + 1) * sizeof(struct ieee80211_reg_rule));
  
  	regd = kzalloc(size_of_regd, GFP_KERNEL);
  	if (!regd)
  		return -ENOMEM;
  
  	memcpy(regd, src_regd, sizeof(struct ieee80211_regdomain));
  
  	for (i = 0; i < src_regd->n_reg_rules; i++)
  		memcpy(&regd->reg_rules[i], &src_regd->reg_rules[i],
  			sizeof(struct ieee80211_reg_rule));
  
  	*dst_regd = regd;
  	return 0;
  }
  
  #ifdef CONFIG_CFG80211_INTERNAL_REGDB
  struct reg_regdb_search_request {
  	char alpha2[2];
  	struct list_head list;
  };
  
  static LIST_HEAD(reg_regdb_search_list);

  static DEFINE_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;
  	int i, r;

  	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 (!memcmp(request->alpha2, curdom->alpha2, 2)) {
  				r = reg_copy_regd(&regdom, curdom);
  				if (r)
  					break;

  				mutex_lock(&cfg80211_mutex);
  				set_regdom(regdom);
  				mutex_unlock(&cfg80211_mutex);

  				break;
  			}
  		}
  
  		kfree(request);
  	}

  	mutex_unlock(&reg_regdb_search_mutex);

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

  /*
   * This lets us keep regulatory code which is updated on a regulatory
   * basis in userspace.
   */

  static int call_crda(const char *alpha2)
  {
  	char country_env[9 + 2] = "COUNTRY=";
  	char *envp[] = {
  		country_env,
  		NULL
  	};
  
  	if (!is_world_regdom((char *) alpha2))

  		pr_info("Calling CRDA for country: %c%c
  ",

  			alpha2[0], alpha2[1]);
  	else

  		pr_info("Calling CRDA to update world regulatory domain
  ");

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

  	country_env[8] = alpha2[0];
  	country_env[9] = alpha2[1];
  
  	return kobject_uevent_env(&reg_pdev->dev.kobj, KOBJ_CHANGE, envp);
  }

  /* Used by nl80211 before kmalloc'ing our regulatory domain */

  bool reg_is_valid_request(const char *alpha2)

  {

  	assert_cfg80211_lock();

  	if (!last_request)
  		return false;
  
  	return alpha2_equal(last_request->alpha2, alpha2);

  }

  /* Sanity check on a regulatory rule */

  static bool is_valid_reg_rule(const struct ieee80211_reg_rule *rule)

  {

  	const struct ieee80211_freq_range *freq_range = &rule->freq_range;

  	u32 freq_diff;

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

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

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

  		return false;
  
  	return true;
  }

  static bool is_valid_rd(const struct ieee80211_regdomain *rd)

  {

  	const struct ieee80211_reg_rule *reg_rule = NULL;

  	unsigned int i;

  	if (!rd->n_reg_rules)
  		return false;

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

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

  }

  static bool reg_does_bw_fit(const struct ieee80211_freq_range *freq_range,
  			    u32 center_freq_khz,
  			    u32 bw_khz)

  {

  	u32 start_freq_khz, end_freq_khz;
  
  	start_freq_khz = center_freq_khz - (bw_khz/2);
  	end_freq_khz = center_freq_khz + (bw_khz/2);
  
  	if (start_freq_khz >= freq_range->start_freq_khz &&
  	    end_freq_khz <= freq_range->end_freq_khz)
  		return true;
  
  	return false;

  }

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

  /*

   * Helper for regdom_intersect(), this does the real
   * mathematical intersection fun
   */

  static int reg_rules_intersect(
  	const struct ieee80211_reg_rule *rule1,
  	const struct ieee80211_reg_rule *rule2,
  	struct ieee80211_reg_rule *intersected_rule)
  {
  	const struct ieee80211_freq_range *freq_range1, *freq_range2;
  	struct ieee80211_freq_range *freq_range;
  	const struct ieee80211_power_rule *power_rule1, *power_rule2;
  	struct ieee80211_power_rule *power_rule;
  	u32 freq_diff;
  
  	freq_range1 = &rule1->freq_range;
  	freq_range2 = &rule2->freq_range;
  	freq_range = &intersected_rule->freq_range;
  
  	power_rule1 = &rule1->power_rule;
  	power_rule2 = &rule2->power_rule;
  	power_rule = &intersected_rule->power_rule;
  
  	freq_range->start_freq_khz = max(freq_range1->start_freq_khz,
  		freq_range2->start_freq_khz);
  	freq_range->end_freq_khz = min(freq_range1->end_freq_khz,
  		freq_range2->end_freq_khz);
  	freq_range->max_bandwidth_khz = min(freq_range1->max_bandwidth_khz,
  		freq_range2->max_bandwidth_khz);
  
  	freq_diff = freq_range->end_freq_khz - freq_range->start_freq_khz;
  	if (freq_range->max_bandwidth_khz > freq_diff)
  		freq_range->max_bandwidth_khz = freq_diff;
  
  	power_rule->max_eirp = min(power_rule1->max_eirp,
  		power_rule2->max_eirp);
  	power_rule->max_antenna_gain = min(power_rule1->max_antenna_gain,
  		power_rule2->max_antenna_gain);
  
  	intersected_rule->flags = (rule1->flags | rule2->flags);
  
  	if (!is_valid_reg_rule(intersected_rule))
  		return -EINVAL;
  
  	return 0;
  }
  
  /**
   * regdom_intersect - do the intersection between two regulatory domains
   * @rd1: first regulatory domain
   * @rd2: second regulatory domain
   *
   * Use this function to get the intersection between two regulatory domains.
   * Once completed we will mark the alpha2 for the rd as intersected, "98",
   * as no one single alpha2 can represent this regulatory domain.
   *
   * Returns a pointer to the regulatory domain structure which will hold the
   * resulting intersection of rules between rd1 and rd2. We will
   * kzalloc() this structure for you.
   */
  static struct ieee80211_regdomain *regdom_intersect(
  	const struct ieee80211_regdomain *rd1,
  	const struct ieee80211_regdomain *rd2)
  {
  	int r, size_of_regd;
  	unsigned int x, y;
  	unsigned int num_rules = 0, rule_idx = 0;
  	const struct ieee80211_reg_rule *rule1, *rule2;
  	struct ieee80211_reg_rule *intersected_rule;
  	struct ieee80211_regdomain *rd;
  	/* This is just a dummy holder to help us count */
  	struct ieee80211_reg_rule irule;
  
  	/* Uses the stack temporarily for counter arithmetic */
  	intersected_rule = &irule;
  
  	memset(intersected_rule, 0, sizeof(struct ieee80211_reg_rule));
  
  	if (!rd1 || !rd2)
  		return NULL;

  	/*
  	 * First we get a count of the rules we'll need, then we actually

  	 * build them. This is to so we can malloc() and free() a
  	 * regdomain once. The reason we use reg_rules_intersect() here
  	 * is it will return -EINVAL if the rule computed makes no sense.

  	 * All rules that do check out OK are valid.
  	 */

  
  	for (x = 0; x < rd1->n_reg_rules; x++) {
  		rule1 = &rd1->reg_rules[x];
  		for (y = 0; y < rd2->n_reg_rules; y++) {
  			rule2 = &rd2->reg_rules[y];
  			if (!reg_rules_intersect(rule1, rule2,
  					intersected_rule))
  				num_rules++;
  			memset(intersected_rule, 0,
  					sizeof(struct ieee80211_reg_rule));
  		}
  	}
  
  	if (!num_rules)
  		return NULL;
  
  	size_of_regd = sizeof(struct ieee80211_regdomain) +
  		((num_rules + 1) * sizeof(struct ieee80211_reg_rule));
  
  	rd = kzalloc(size_of_regd, GFP_KERNEL);
  	if (!rd)
  		return NULL;
  
  	for (x = 0; x < rd1->n_reg_rules; x++) {
  		rule1 = &rd1->reg_rules[x];
  		for (y = 0; y < rd2->n_reg_rules; y++) {
  			rule2 = &rd2->reg_rules[y];

  			/*
  			 * This time around instead of using the stack lets

  			 * write to the target rule directly saving ourselves

  			 * a memcpy()
  			 */

  			intersected_rule = &rd->reg_rules[rule_idx];
  			r = reg_rules_intersect(rule1, rule2,
  				intersected_rule);

  			/*
  			 * No need to memset here the intersected rule here as
  			 * we're not using the stack anymore
  			 */

  			if (r)
  				continue;
  			rule_idx++;
  		}
  	}
  
  	if (rule_idx != num_rules) {
  		kfree(rd);
  		return NULL;
  	}
  
  	rd->n_reg_rules = num_rules;
  	rd->alpha2[0] = '9';
  	rd->alpha2[1] = '8';
  
  	return rd;
  }

  /*
   * XXX: add support for the rest of enum nl80211_reg_rule_flags, we may
   * want to just have the channel structure use these
   */

  static u32 map_regdom_flags(u32 rd_flags)
  {
  	u32 channel_flags = 0;
  	if (rd_flags & NL80211_RRF_PASSIVE_SCAN)
  		channel_flags |= IEEE80211_CHAN_PASSIVE_SCAN;
  	if (rd_flags & NL80211_RRF_NO_IBSS)
  		channel_flags |= IEEE80211_CHAN_NO_IBSS;
  	if (rd_flags & NL80211_RRF_DFS)
  		channel_flags |= IEEE80211_CHAN_RADAR;
  	return channel_flags;
  }

  static int freq_reg_info_regd(struct wiphy *wiphy,
  			      u32 center_freq,

  			      u32 desired_bw_khz,

  			      const struct ieee80211_reg_rule **reg_rule,
  			      const struct ieee80211_regdomain *custom_regd)

  {
  	int i;

  	bool band_rule_found = false;

  	const struct ieee80211_regdomain *regd;

  	bool bw_fits = false;
  
  	if (!desired_bw_khz)
  		desired_bw_khz = MHZ_TO_KHZ(20);

  	regd = custom_regd ? custom_regd : cfg80211_regdomain;

  	/*
  	 * Follow the driver's regulatory domain, if present, unless a country
  	 * IE has been processed or a user wants to help complaince further
  	 */

  	if (!custom_regd &&
  	    last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&

  	    last_request->initiator != NL80211_REGDOM_SET_BY_USER &&

  	    wiphy->regd)
  		regd = wiphy->regd;
  
  	if (!regd)

  		return -EINVAL;

  	for (i = 0; i < regd->n_reg_rules; i++) {

  		const struct ieee80211_reg_rule *rr;
  		const struct ieee80211_freq_range *fr = NULL;
  		const struct ieee80211_power_rule *pr = NULL;

  		rr = &regd->reg_rules[i];

  		fr = &rr->freq_range;
  		pr = &rr->power_rule;

  		/*
  		 * We only need to know if one frequency rule was

  		 * was in center_freq's band, that's enough, so lets

  		 * not overwrite it once found
  		 */

  		if (!band_rule_found)
  			band_rule_found = freq_in_rule_band(fr, center_freq);

  		bw_fits = reg_does_bw_fit(fr,
  					  center_freq,
  					  desired_bw_khz);

  		if (band_rule_found && bw_fits) {

  			*reg_rule = rr;

  			return 0;

  		}
  	}

  	if (!band_rule_found)
  		return -ERANGE;

  	return -EINVAL;

  }

  int freq_reg_info(struct wiphy *wiphy,
  		  u32 center_freq,
  		  u32 desired_bw_khz,
  		  const struct ieee80211_reg_rule **reg_rule)

  {

  	assert_cfg80211_lock();

  	return freq_reg_info_regd(wiphy,
  				  center_freq,
  				  desired_bw_khz,
  				  reg_rule,
  				  NULL);

  }

  EXPORT_SYMBOL(freq_reg_info);

  #ifdef CONFIG_CFG80211_REG_DEBUG
  static const char *reg_initiator_name(enum nl80211_reg_initiator initiator)
  {
  	switch (initiator) {
  	case NL80211_REGDOM_SET_BY_CORE:
  		return "Set by core";
  	case NL80211_REGDOM_SET_BY_USER:
  		return "Set by user";
  	case NL80211_REGDOM_SET_BY_DRIVER:
  		return "Set by driver";
  	case NL80211_REGDOM_SET_BY_COUNTRY_IE:
  		return "Set by country IE";
  	default:
  		WARN_ON(1);
  		return "Set by bug";
  	}
  }

  
  static void chan_reg_rule_print_dbg(struct ieee80211_channel *chan,
  				    u32 desired_bw_khz,
  				    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];
  
  	power_rule = &reg_rule->power_rule;
  	freq_range = &reg_rule->freq_range;
  
  	if (!power_rule->max_antenna_gain)
  		snprintf(max_antenna_gain, 32, "N/A");
  	else
  		snprintf(max_antenna_gain, 32, "%d", power_rule->max_antenna_gain);

  	REG_DBG_PRINT("Updating information on frequency %d MHz "

  		      "for a %d MHz width channel with regulatory rule:
  ",

  		      chan->center_freq,
  		      KHZ_TO_MHZ(desired_bw_khz));

  	REG_DBG_PRINT("%d KHz - %d KHz @  KHz), (%s mBi, %d mBm)
  ",

  		      freq_range->start_freq_khz,
  		      freq_range->end_freq_khz,
  		      max_antenna_gain,
  		      power_rule->max_eirp);
  }
  #else
  static void chan_reg_rule_print_dbg(struct ieee80211_channel *chan,
  				    u32 desired_bw_khz,
  				    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). To support
   * smaller custom bandwidths such as 5 MHz or 10 MHz we'll need a
   * new ieee80211_channel.target_bw and re run the regulatory check
   * on the wiphy with the target_bw specified. Then we can simply use
   * that below for the desired_bw_khz below.
   */

  static void handle_channel(struct wiphy *wiphy,
  			   enum nl80211_reg_initiator initiator,
  			   enum ieee80211_band band,

  			   unsigned int chan_idx)

  {
  	int r;

  	u32 flags, bw_flags = 0;
  	u32 desired_bw_khz = MHZ_TO_KHZ(20);

  	const struct ieee80211_reg_rule *reg_rule = NULL;
  	const struct ieee80211_power_rule *power_rule = NULL;

  	const struct ieee80211_freq_range *freq_range = NULL;

  	struct ieee80211_supported_band *sband;
  	struct ieee80211_channel *chan;

  	struct wiphy *request_wiphy = NULL;

  	assert_cfg80211_lock();

  	request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx);

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

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

  	if (r) {
  		/*
  		 * We will disable all channels that do not match our
  		 * recieved 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 &&
  		    r == -ERANGE)
  			return;

  		REG_DBG_PRINT("Disabling freq %d MHz
  ", chan->center_freq);

  		chan->flags = IEEE80211_CHAN_DISABLED;

  		return;

  	}

  	chan_reg_rule_print_dbg(chan, desired_bw_khz, reg_rule);

  	power_rule = &reg_rule->power_rule;

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

  	if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER &&

  	    request_wiphy && request_wiphy == wiphy &&

  	    request_wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY) {

  		/*
  		 * This gaurantees the driver's requested regulatory domain

  		 * will always be used as a base for further regulatory

  		 * settings
  		 */

  		chan->flags = chan->orig_flags =

  			map_regdom_flags(reg_rule->flags) | bw_flags;

  		chan->max_antenna_gain = chan->orig_mag =
  			(int) MBI_TO_DBI(power_rule->max_antenna_gain);

  		chan->max_power = chan->orig_mpwr =
  			(int) MBM_TO_DBM(power_rule->max_eirp);
  		return;
  	}

  	chan->flags = flags | bw_flags | map_regdom_flags(reg_rule->flags);

  	chan->max_antenna_gain = min(chan->orig_mag,

  		(int) MBI_TO_DBI(power_rule->max_antenna_gain));

  	if (chan->orig_mpwr)

  		chan->max_power = min(chan->orig_mpwr,
  			(int) MBM_TO_DBM(power_rule->max_eirp));

  	else

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

  }

  static void handle_band(struct wiphy *wiphy,
  			enum ieee80211_band band,
  			enum nl80211_reg_initiator initiator)

  {

  	unsigned int i;
  	struct ieee80211_supported_band *sband;
  
  	BUG_ON(!wiphy->bands[band]);
  	sband = wiphy->bands[band];

  
  	for (i = 0; i < sband->n_channels; i++)

  		handle_channel(wiphy, initiator, band, i);

  }

  static bool ignore_reg_update(struct wiphy *wiphy,
  			      enum nl80211_reg_initiator initiator)

  {

  	if (!last_request) {

  		REG_DBG_PRINT("Ignoring regulatory request %s since "

  			      "last_request is not set
  ",
  			      reg_initiator_name(initiator));

  		return true;

  	}

  	if (initiator == NL80211_REGDOM_SET_BY_CORE &&

  	    wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY) {

  		REG_DBG_PRINT("Ignoring regulatory request %s "

  			      "since the driver uses its own custom "
  			      "regulatory domain ",
  			      reg_initiator_name(initiator));

  		return true;

  	}

  	/*
  	 * wiphy->regd will be set once the device has its own
  	 * desired regulatory domain set
  	 */

  	if (wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY && !wiphy->regd &&

  	    initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&

  	    !is_world_regdom(last_request->alpha2)) {

  		REG_DBG_PRINT("Ignoring regulatory request %s "

  			      "since the driver requires its own regulaotry "
  			      "domain to be set first",
  			      reg_initiator_name(initiator));

  		return true;

  	}

  	return false;
  }

  static void update_all_wiphy_regulatory(enum nl80211_reg_initiator initiator)

  {

  	struct cfg80211_registered_device *rdev;

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

  }

  static void handle_reg_beacon(struct wiphy *wiphy,
  			      unsigned int chan_idx,
  			      struct reg_beacon *reg_beacon)
  {

  	struct ieee80211_supported_band *sband;
  	struct ieee80211_channel *chan;

  	bool channel_changed = false;
  	struct ieee80211_channel chan_before;

  
  	assert_cfg80211_lock();
  
  	sband = wiphy->bands[reg_beacon->chan.band];
  	chan = &sband->channels[chan_idx];
  
  	if (likely(chan->center_freq != reg_beacon->chan.center_freq))
  		return;

  	if (chan->beacon_found)
  		return;
  
  	chan->beacon_found = true;

  	if (wiphy->flags & WIPHY_FLAG_DISABLE_BEACON_HINTS)

  		return;

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

  	if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) {

  		chan->flags &= ~IEEE80211_CHAN_PASSIVE_SCAN;

  		channel_changed = true;

  	}

  	if (chan->flags & IEEE80211_CHAN_NO_IBSS) {

  		chan->flags &= ~IEEE80211_CHAN_NO_IBSS;

  		channel_changed = true;

  	}

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

  }
  
  /*
   * Called when a scan on a wiphy finds a beacon on
   * new channel
   */
  static void wiphy_update_new_beacon(struct wiphy *wiphy,
  				    struct reg_beacon *reg_beacon)
  {
  	unsigned int i;
  	struct ieee80211_supported_band *sband;
  
  	assert_cfg80211_lock();
  
  	if (!wiphy->bands[reg_beacon->chan.band])
  		return;
  
  	sband = wiphy->bands[reg_beacon->chan.band];
  
  	for (i = 0; i < sband->n_channels; i++)
  		handle_reg_beacon(wiphy, i, reg_beacon);
  }
  
  /*
   * Called upon reg changes or a new wiphy is added
   */
  static void wiphy_update_beacon_reg(struct wiphy *wiphy)
  {
  	unsigned int i;
  	struct ieee80211_supported_band *sband;
  	struct reg_beacon *reg_beacon;
  
  	assert_cfg80211_lock();
  
  	if (list_empty(&reg_beacon_list))
  		return;
  
  	list_for_each_entry(reg_beacon, &reg_beacon_list, list) {
  		if (!wiphy->bands[reg_beacon->chan.band])
  			continue;
  		sband = wiphy->bands[reg_beacon->chan.band];
  		for (i = 0; i < sband->n_channels; i++)
  			handle_reg_beacon(wiphy, i, reg_beacon);
  	}
  }
  
  static bool reg_is_world_roaming(struct wiphy *wiphy)
  {
  	if (is_world_regdom(cfg80211_regdomain->alpha2) ||
  	    (wiphy->regd && is_world_regdom(wiphy->regd->alpha2)))
  		return true;

  	if (last_request &&
  	    last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&

  	    wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY)

  		return true;
  	return false;
  }
  
  /* Reap the advantages of previously found beacons */
  static void reg_process_beacons(struct wiphy *wiphy)
  {

  	/*
  	 * Means we are just firing up cfg80211, so no beacons would
  	 * have been processed yet.
  	 */
  	if (!last_request)
  		return;

  	if (!reg_is_world_roaming(wiphy))
  		return;
  	wiphy_update_beacon_reg(wiphy);
  }

  static bool is_ht40_not_allowed(struct ieee80211_channel *chan)
  {
  	if (!chan)
  		return true;
  	if (chan->flags & IEEE80211_CHAN_DISABLED)
  		return true;
  	/* This would happen when regulatory rules disallow HT40 completely */
  	if (IEEE80211_CHAN_NO_HT40 == (chan->flags & (IEEE80211_CHAN_NO_HT40)))
  		return true;
  	return false;
  }
  
  static void reg_process_ht_flags_channel(struct wiphy *wiphy,
  					 enum ieee80211_band band,
  					 unsigned int chan_idx)
  {
  	struct ieee80211_supported_band *sband;
  	struct ieee80211_channel *channel;
  	struct ieee80211_channel *channel_before = NULL, *channel_after = NULL;
  	unsigned int i;
  
  	assert_cfg80211_lock();
  
  	sband = wiphy->bands[band];
  	BUG_ON(chan_idx >= sband->n_channels);
  	channel = &sband->channels[chan_idx];
  
  	if (is_ht40_not_allowed(channel)) {
  		channel->flags |= IEEE80211_CHAN_NO_HT40;
  		return;
  	}
  
  	/*
  	 * We need to ensure the extension channels exist to
  	 * be able to use HT40- or HT40+, this finds them (or not)
  	 */
  	for (i = 0; i < sband->n_channels; i++) {
  		struct ieee80211_channel *c = &sband->channels[i];
  		if (c->center_freq == (channel->center_freq - 20))
  			channel_before = c;
  		if (c->center_freq == (channel->center_freq + 20))
  			channel_after = c;
  	}
  
  	/*
  	 * Please note that this assumes target bandwidth is 20 MHz,
  	 * if that ever changes we also need to change the below logic
  	 * to include that as well.
  	 */
  	if (is_ht40_not_allowed(channel_before))

  		channel->flags |= IEEE80211_CHAN_NO_HT40MINUS;

  	else

  		channel->flags &= ~IEEE80211_CHAN_NO_HT40MINUS;

  
  	if (is_ht40_not_allowed(channel_after))

  		channel->flags |= IEEE80211_CHAN_NO_HT40PLUS;

  	else

  		channel->flags &= ~IEEE80211_CHAN_NO_HT40PLUS;

  }
  
  static void reg_process_ht_flags_band(struct wiphy *wiphy,
  				      enum ieee80211_band band)
  {
  	unsigned int i;
  	struct ieee80211_supported_band *sband;
  
  	BUG_ON(!wiphy->bands[band]);
  	sband = wiphy->bands[band];
  
  	for (i = 0; i < sband->n_channels; i++)
  		reg_process_ht_flags_channel(wiphy, band, i);
  }
  
  static void reg_process_ht_flags(struct wiphy *wiphy)
  {
  	enum ieee80211_band band;
  
  	if (!wiphy)
  		return;
  
  	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
  		if (wiphy->bands[band])
  			reg_process_ht_flags_band(wiphy, band);
  	}
  
  }

  void wiphy_update_regulatory(struct wiphy *wiphy,
  			     enum nl80211_reg_initiator initiator)

  {
  	enum ieee80211_band band;

  	if (ignore_reg_update(wiphy, initiator))

  		goto out;

  	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {

  		if (wiphy->bands[band])

  			handle_band(wiphy, band, initiator);

  	}

  out:
  	reg_process_beacons(wiphy);

  	reg_process_ht_flags(wiphy);

  	if (wiphy->reg_notifier)

  		wiphy->reg_notifier(wiphy, last_request);

  }

  static void handle_channel_custom(struct wiphy *wiphy,
  				  enum ieee80211_band band,
  				  unsigned int chan_idx,
  				  const struct ieee80211_regdomain *regd)
  {
  	int r;

  	u32 desired_bw_khz = MHZ_TO_KHZ(20);
  	u32 bw_flags = 0;

  	const struct ieee80211_reg_rule *reg_rule = NULL;
  	const struct ieee80211_power_rule *power_rule = NULL;

  	const struct ieee80211_freq_range *freq_range = NULL;

  	struct ieee80211_supported_band *sband;
  	struct ieee80211_channel *chan;

  	assert_reg_lock();

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

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

  
  	if (r) {

  		REG_DBG_PRINT("Disabling freq %d MHz as custom "

  			      "regd has no rule that fits a %d MHz "
  			      "wide channel
  ",
  			      chan->center_freq,
  			      KHZ_TO_MHZ(desired_bw_khz));

  		chan->flags = IEEE80211_CHAN_DISABLED;
  		return;
  	}

  	chan_reg_rule_print_dbg(chan, desired_bw_khz, reg_rule);

  	power_rule = &reg_rule->power_rule;

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

  	chan->flags |= map_regdom_flags(reg_rule->flags) | bw_flags;

  	chan->max_antenna_gain = (int) MBI_TO_DBI(power_rule->max_antenna_gain);

  	chan->max_power = (int) MBM_TO_DBM(power_rule->max_eirp);
  }
  
  static void handle_band_custom(struct wiphy *wiphy, enum ieee80211_band band,
  			       const struct ieee80211_regdomain *regd)
  {
  	unsigned int i;
  	struct ieee80211_supported_band *sband;
  
  	BUG_ON(!wiphy->bands[band]);
  	sband = wiphy->bands[band];
  
  	for (i = 0; i < sband->n_channels; i++)
  		handle_channel_custom(wiphy, band, i, regd);
  }
  
  /* Used by drivers prior to wiphy registration */
  void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
  				   const struct ieee80211_regdomain *regd)
  {
  	enum ieee80211_band band;

  	unsigned int bands_set = 0;

  	mutex_lock(&reg_mutex);

  	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {

  		if (!wiphy->bands[band])
  			continue;
  		handle_band_custom(wiphy, band, regd);
  		bands_set++;

  	}

  	mutex_unlock(&reg_mutex);

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

  }

  EXPORT_SYMBOL(wiphy_apply_custom_regulatory);

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

  #define REG_INTERSECT	1

  /* This has the logic which determines when a new request
   * should be ignored. */

  static int ignore_request(struct wiphy *wiphy,
  			  struct regulatory_request *pending_request)

  {

  	struct wiphy *last_wiphy = NULL;

  
  	assert_cfg80211_lock();

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

  	switch (pending_request->initiator) {

  	case NL80211_REGDOM_SET_BY_CORE:

  		return 0;

  	case NL80211_REGDOM_SET_BY_COUNTRY_IE:

  
  		last_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx);

  		if (unlikely(!is_an_alpha2(pending_request->alpha2)))

  			return -EINVAL;

  		if (last_request->initiator ==
  		    NL80211_REGDOM_SET_BY_COUNTRY_IE) {

  			if (last_wiphy != wiphy) {

  				/*
  				 * Two cards with two APs claiming different

  				 * Country IE alpha2s. We could

  				 * intersect them, but that seems unlikely
  				 * to be correct. Reject second one for now.
  				 */

  				if (regdom_changes(pending_request->alpha2))

  					return -EOPNOTSUPP;
  				return -EALREADY;
  			}

  			/*
  			 * Two consecutive Country IE hints on the same wiphy.
  			 * This should be picked up early by the driver/stack
  			 */

  			if (WARN_ON(regdom_changes(pending_request->alpha2)))

  				return 0;
  			return -EALREADY;
  		}

  		return 0;

  	case NL80211_REGDOM_SET_BY_DRIVER:
  		if (last_request->initiator == NL80211_REGDOM_SET_BY_CORE) {

  			if (regdom_changes(pending_request->alpha2))

  				return 0;

  			return -EALREADY;

  		}

  
  		/*
  		 * This would happen if you unplug and plug your card
  		 * back in or if you add a new device for which the previously
  		 * loaded card also agrees on the regulatory domain.
  		 */

  		if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER &&

  		    !regdom_changes(pending_request->alpha2))

  			return -EALREADY;

  		return REG_INTERSECT;

  	case NL80211_REGDOM_SET_BY_USER:
  		if (last_request->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE)

  			return REG_INTERSECT;

  		/*
  		 * If the user knows better the user should set the regdom
  		 * to their country before the IE is picked up
  		 */

  		if (last_request->initiator == NL80211_REGDOM_SET_BY_USER &&

  			  last_request->intersect)
  			return -EOPNOTSUPP;

  		/*
  		 * Process user requests only after previous user/driver/core
  		 * requests have been processed
  		 */

  		if (last_request->initiator == NL80211_REGDOM_SET_BY_CORE ||
  		    last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER ||
  		    last_request->initiator == NL80211_REGDOM_SET_BY_USER) {

  			if (regdom_changes(last_request->alpha2))

  				return -EAGAIN;
  		}

  		if (!regdom_changes(pending_request->alpha2))

  			return -EALREADY;

  		return 0;
  	}
  
  	return -EINVAL;
  }

  static void reg_set_request_processed(void)
  {
  	bool need_more_processing = false;
  
  	last_request->processed = true;
  
  	spin_lock(&reg_requests_lock);
  	if (!list_empty(&reg_requests_list))
  		need_more_processing = true;
  	spin_unlock(&reg_requests_lock);
  
  	if (need_more_processing)
  		schedule_work(&reg_work);
  }

  /**
   * __regulatory_hint - hint to the wireless core a regulatory domain
   * @wiphy: if the hint comes from country information from an AP, this
   *	is required to be set to the wiphy that received the information

   * @pending_request: the regulatory request currently being processed

   *
   * The Wireless subsystem can use this function to hint to the wireless core

   * what it believes should be the current regulatory domain.

   *
   * Returns zero if all went fine, %-EALREADY if a regulatory domain had
   * already been set or other standard error codes.
   *

   * Caller must hold &cfg80211_mutex and &reg_mutex

   */

  static int __regulatory_hint(struct wiphy *wiphy,
  			     struct regulatory_request *pending_request)

  {

  	bool intersect = false;

  	int r = 0;

  	assert_cfg80211_lock();

  	r = ignore_request(wiphy, pending_request);

  	if (r == REG_INTERSECT) {

  		if (pending_request->initiator ==
  		    NL80211_REGDOM_SET_BY_DRIVER) {

  			r = reg_copy_regd(&wiphy->regd, cfg80211_regdomain);

  			if (r) {
  				kfree(pending_request);

  				return r;

  			}

  		}

  		intersect = true;

  	} else if (r) {

  		/*
  		 * If the regulatory domain being requested by the

  		 * driver has already been set just copy it to the

  		 * wiphy
  		 */

  		if (r == -EALREADY &&

  		    pending_request->initiator ==
  		    NL80211_REGDOM_SET_BY_DRIVER) {

  			r = reg_copy_regd(&wiphy->regd, cfg80211_regdomain);

  			if (r) {
  				kfree(pending_request);

  				return r;

  			}

  			r = -EALREADY;
  			goto new_request;
  		}

  		kfree(pending_request);

  		return r;

  	}

  new_request:

  	kfree(last_request);

  	last_request = pending_request;
  	last_request->intersect = intersect;

  	pending_request = NULL;

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

  	/* When r == REG_INTERSECT we do need to call CRDA */

  	if (r < 0) {
  		/*
  		 * Since CRDA will not be called in this case as we already
  		 * have applied the requested regulatory domain before we just
  		 * inform userspace we have processed the request
  		 */

  		if (r == -EALREADY) {

  			nl80211_send_reg_change_event(last_request);

  			reg_set_request_processed();
  		}

  		return r;

  	}

  	return call_crda(last_request->alpha2);

  }

  /* This processes *all* regulatory hints */

  static void reg_process_hint(struct regulatory_request *reg_request)

  {
  	int r = 0;
  	struct wiphy *wiphy = NULL;

  	enum nl80211_reg_initiator initiator = reg_request->initiator;

  
  	BUG_ON(!reg_request->alpha2);

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

  	if (reg_request->initiator == NL80211_REGDOM_SET_BY_DRIVER &&

  	    !wiphy) {

  		kfree(reg_request);

  		return;

  	}

  	r = __regulatory_hint(wiphy, reg_request);

  	/* This is required so that the orig_* parameters are saved */

  	if (r == -EALREADY && wiphy &&
  	    wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY)

  		wiphy_update_regulatory(wiphy, initiator);

  }

  /*
   * 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;

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

  	/* When last_request->processed becomes true this will be rescheduled */
  	if (last_request && !last_request->processed) {
  		REG_DBG_PRINT("Pending regulatory request, waiting "
  			      "for it to be processed...");
  		goto out;
  	}

  	spin_lock(&reg_requests_lock);

  	if (list_empty(&reg_requests_list)) {

  		spin_unlock(&reg_requests_lock);

  		goto out;

  	}

  
  	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);
  
  out:

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

  }

  /* Processes beacon hints -- this has nothing to do with country IEs */
  static void reg_process_pending_beacon_hints(void)
  {

  	struct cfg80211_registered_device *rdev;

  	struct reg_beacon *pending_beacon, *tmp;

  	/*
  	 * No need to hold the reg_mutex here as we just touch wiphys
  	 * and do not read or access regulatory variables.
  	 */

  	mutex_lock(&cfg80211_mutex);
  
  	/* This goes through the _pending_ beacon list */
  	spin_lock_bh(&reg_pending_beacons_lock);
  
  	if (list_empty(&reg_pending_beacons)) {
  		spin_unlock_bh(&reg_pending_beacons_lock);
  		goto out;
  	}
  
  	list_for_each_entry_safe(pending_beacon, tmp,
  				 &reg_pending_beacons, list) {
  
  		list_del_init(&pending_beacon->list);
  
  		/* Applies the beacon hint to current wiphys */

  		list_for_each_entry(rdev, &cfg80211_rdev_list, list)
  			wiphy_update_new_beacon(&rdev->wiphy, pending_beacon);

  
  		/* Remembers the beacon hint for new wiphys or reg changes */
  		list_add_tail(&pending_beacon->list, &reg_beacon_list);
  	}
  
  	spin_unlock_bh(&reg_pending_beacons_lock);
  out:
  	mutex_unlock(&cfg80211_mutex);
  }

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

  	reg_process_pending_beacon_hints();

  }

  static void queue_regulatory_request(struct regulatory_request *request)
  {

  	if (isalpha(request->alpha2[0]))
  		request->alpha2[0] = toupper(request->alpha2[0]);
  	if (isalpha(request->alpha2[1]))
  		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;

  	kfree(last_request);
  	last_request = NULL;

  
  	request = kzalloc(sizeof(struct regulatory_request),
  			  GFP_KERNEL);
  	if (!request)
  		return -ENOMEM;
  
  	request->alpha2[0] = alpha2[0];
  	request->alpha2[1] = alpha2[1];

  	request->initiator = NL80211_REGDOM_SET_BY_CORE;

  	queue_regulatory_request(request);

  	return 0;

  }

  /* User hints */
  int regulatory_hint_user(const char *alpha2)

  {

  	struct regulatory_request *request;

  	BUG_ON(!alpha2);

  	request = kzalloc(sizeof(struct regulatory_request), GFP_KERNEL);
  	if (!request)
  		return -ENOMEM;
  
  	request->wiphy_idx = WIPHY_IDX_STALE;
  	request->alpha2[0] = alpha2[0];
  	request->alpha2[1] = alpha2[1];

  	request->initiator = NL80211_REGDOM_SET_BY_USER;

  
  	queue_regulatory_request(request);
  
  	return 0;
  }
  
  /* Driver hints */
  int regulatory_hint(struct wiphy *wiphy, const char *alpha2)
  {
  	struct regulatory_request *request;
  
  	BUG_ON(!alpha2);
  	BUG_ON(!wiphy);
  
  	request = kzalloc(sizeof(struct regulatory_request), GFP_KERNEL);
  	if (!request)
  		return -ENOMEM;
  
  	request->wiphy_idx = get_wiphy_idx(wiphy);
  
  	/* Must have registered wiphy first */
  	BUG_ON(!wiphy_idx_valid(request->wiphy_idx));
  
  	request->alpha2[0] = alpha2[0];
  	request->alpha2[1] = alpha2[1];

  	request->initiator = NL80211_REGDOM_SET_BY_DRIVER;

  
  	queue_regulatory_request(request);
  
  	return 0;

  }
  EXPORT_SYMBOL(regulatory_hint);

  /*
   * We hold wdev_lock() here so we cannot hold cfg80211_mutex() and
   * therefore cannot iterate over the rdev list here.
   */

  void regulatory_hint_11d(struct wiphy *wiphy,

  			 enum ieee80211_band band,
  			 u8 *country_ie,
  			 u8 country_ie_len)

  {

  	char alpha2[2];

  	enum environment_cap env = ENVIRON_ANY;

  	struct regulatory_request *request;

  	mutex_lock(&reg_mutex);

  	if (unlikely(!last_request))
  		goto out;

  	/* IE len must be evenly divisible by 2 */
  	if (country_ie_len & 0x01)
  		goto out;
  
  	if (country_ie_len < IEEE80211_COUNTRY_IE_MIN_LEN)
  		goto out;

  	alpha2[0] = country_ie[0];
  	alpha2[1] = country_ie[1];
  
  	if (country_ie[2] == 'I')
  		env = ENVIRON_INDOOR;
  	else if (country_ie[2] == 'O')
  		env = ENVIRON_OUTDOOR;

  	/*

  	 * We will run this only upon a successful connection on cfg80211.

  	 * We leave conflict resolution to the workqueue, where can hold
  	 * cfg80211_mutex.

  	 */

  	if (likely(last_request->initiator ==
  	    NL80211_REGDOM_SET_BY_COUNTRY_IE &&

  	    wiphy_idx_valid(last_request->wiphy_idx)))
  		goto out;

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

  		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;

  	mutex_unlock(&reg_mutex);

  	queue_regulatory_request(request);
  
  	return;

  out:

  	mutex_unlock(&reg_mutex);

  }

  static void restore_alpha2(char *alpha2, bool reset_user)
  {
  	/* indicates there is no alpha2 to consider for restoration */
  	alpha2[0] = '9';
  	alpha2[1] = '7';
  
  	/* The user setting has precedence over the module parameter */
  	if (is_user_regdom_saved()) {
  		/* Unless we're asked to ignore it and reset it */
  		if (reset_user) {

  			REG_DBG_PRINT("Restoring regulatory settings "

  			       "including user preference
  ");
  			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
  ",
  				       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
  ",
  			       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
  ",
  		       ieee80211_regdom[0],
  		       ieee80211_regdom[1]);
  		alpha2[0] = ieee80211_regdom[0];
  		alpha2[1] = ieee80211_regdom[1];
  	} else

  		REG_DBG_PRINT("Restoring regulatory settings
  ");

  }
  
  /*
   * Restoring regulatory settings involves ingoring any
   * possibly stale country IE information and user regulatory
   * settings if so desired, this includes any beacon hints
   * learned as we could have traveled outside to another country
   * after disconnection. To restore regulatory settings we do
   * exactly what we did at bootup:
   *
   *   - send a core regulatory hint
   *   - send a user regulatory hint if applicable
   *
   * Device drivers that send a regulatory hint for a specific country
   * keep their own regulatory domain on wiphy->regd so that does does
   * not need to be remembered.
   */
  static void restore_regulatory_settings(bool reset_user)
  {
  	char alpha2[2];
  	struct reg_beacon *reg_beacon, *btmp;
  
  	mutex_lock(&cfg80211_mutex);
  	mutex_lock(&reg_mutex);
  
  	reset_regdomains();
  	restore_alpha2(alpha2, reset_user);
  
  	/* Clear beacon hints */
  	spin_lock_bh(&reg_pending_beacons_lock);
  	if (!list_empty(&reg_pending_beacons)) {
  		list_for_each_entry_safe(reg_beacon, btmp,
  					 &reg_pending_beacons, list) {
  			list_del(&reg_beacon->list);
  			kfree(reg_beacon);
  		}
  	}
  	spin_unlock_bh(&reg_pending_beacons_lock);
  
  	if (!list_empty(&reg_beacon_list)) {
  		list_for_each_entry_safe(reg_beacon, btmp,
  					 &reg_beacon_list, list) {
  			list_del(&reg_beacon->list);
  			kfree(reg_beacon);
  		}
  	}
  
  	/* First restore to the basic regulatory settings */
  	cfg80211_regdomain = cfg80211_world_regdom;
  
  	mutex_unlock(&reg_mutex);
  	mutex_unlock(&cfg80211_mutex);
  
  	regulatory_hint_core(cfg80211_regdomain->alpha2);
  
  	/*
  	 * This restores the ieee80211_regdom module parameter
  	 * preference or the last user requested regulatory
  	 * settings, user regulatory settings takes precedence.
  	 */
  	if (is_an_alpha2(alpha2))
  		regulatory_hint_user(user_alpha2);
  }
  
  
  void regulatory_hint_disconnect(void)
  {

  	REG_DBG_PRINT("All devices are disconnected, going to "

  		      "restore regulatory settings
  ");
  	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;
  }
  
  int regulatory_hint_found_beacon(struct wiphy *wiphy,
  				 struct ieee80211_channel *beacon_chan,
  				 gfp_t gfp)
  {
  	struct reg_beacon *reg_beacon;
  
  	if (likely((beacon_chan->beacon_found ||
  	    (beacon_chan->flags & IEEE80211_CHAN_RADAR) ||
  	    (beacon_chan->band == IEEE80211_BAND_2GHZ &&
  	     !freq_is_chan_12_13_14(beacon_chan->center_freq)))))
  		return 0;
  
  	reg_beacon = kzalloc(sizeof(struct reg_beacon), gfp);
  	if (!reg_beacon)
  		return -ENOMEM;

  	REG_DBG_PRINT("Found new beacon on "

  		      "frequency: %d MHz (Ch %d) on %s
  ",
  		      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;

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

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

  		/*
  		 * There may not be documentation for max antenna gain
  		 * in certain regions
  		 */

  		if (power_rule->max_antenna_gain)

  			pr_info("    (%d KHz - %d KHz @ %d KHz), (%d mBi, %d mBm)
  ",

  				freq_range->start_freq_khz,
  				freq_range->end_freq_khz,
  				freq_range->max_bandwidth_khz,
  				power_rule->max_antenna_gain,
  				power_rule->max_eirp);
  		else

  			pr_info("    (%d KHz - %d KHz @ %d KHz), (N/A, %d mBm)
  ",

  				freq_range->start_freq_khz,
  				freq_range->end_freq_khz,
  				freq_range->max_bandwidth_khz,
  				power_rule->max_eirp);
  	}
  }

  static void print_regdomain(const struct ieee80211_regdomain *rd)

  {

  	if (is_intersected_alpha2(rd->alpha2)) {

  		if (last_request->initiator ==
  		    NL80211_REGDOM_SET_BY_COUNTRY_IE) {

  			struct cfg80211_registered_device *rdev;
  			rdev = cfg80211_rdev_by_wiphy_idx(

  				last_request->wiphy_idx);

  			if (rdev) {

  				pr_info("Current regulatory domain updated by AP to: %c%c
  ",

  					rdev->country_ie_alpha2[0],
  					rdev->country_ie_alpha2[1]);

  			} else

  				pr_info("Current regulatory domain intersected:
  ");

  		} else

  			pr_info("Current regulatory domain intersected:
  ");

  	} else if (is_world_regdom(rd->alpha2))

  		pr_info("World regulatory domain updated:
  ");

  	else {
  		if (is_unknown_alpha2(rd->alpha2))

  			pr_info("Regulatory domain changed to driver built-in settings (unknown country)
  ");

  		else

  			pr_info("Regulatory domain changed to country: %c%c
  ",

  				rd->alpha2[0], rd->alpha2[1]);
  	}
  	print_rd_rules(rd);
  }

  static void print_regdomain_info(const struct ieee80211_regdomain *rd)

  {

  	pr_info("Regulatory domain: %c%c
  ", rd->alpha2[0], rd->alpha2[1]);

  	print_rd_rules(rd);
  }

  /* Takes ownership of rd only if it doesn't fail */

  static int __set_regdom(const struct ieee80211_regdomain *rd)

  {

  	const struct ieee80211_regdomain *intersected_rd = NULL;

  	struct cfg80211_registered_device *rdev = NULL;

  	struct wiphy *request_wiphy;

  	/* Some basic sanity checks first */

  	if (is_world_regdom(rd->alpha2)) {

  		if (WARN_ON(!reg_is_valid_request(rd->alpha2)))

  			return -EINVAL;
  		update_world_regdomain(rd);
  		return 0;
  	}

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

  	if (!last_request)

  		return -EINVAL;

  	/*
  	 * Lets only bother proceeding on the same alpha2 if the current

  	 * rd is non static (it means CRDA was present and was used last)

  	 * and the pending request came in from a country IE
  	 */

  	if (last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE) {

  		/*
  		 * If someone else asked us to change the rd lets only bother
  		 * checking if the alpha2 changes if CRDA was already called
  		 */

  		if (!regdom_changes(rd->alpha2))

  			return -EINVAL;
  	}

  	/*
  	 * Now lets set the regulatory domain, update all driver channels

  	 * and finally inform them of what we have done, in case they want
  	 * to review or adjust their own settings based on their own

  	 * internal EEPROM data
  	 */