1 files changed, 158 insertions, 8 deletions

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 34983a825ac..3f18a1d03a5 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -50,6 +50,7 @@ struct regulatory_request {
 	struct wiphy *wiphy;
 	enum reg_set_by initiator;
 	char alpha2[2];
+	bool intersect;
 };
 
 static struct regulatory_request *last_request;
@@ -359,6 +360,143 @@ static u32 freq_max_bandwidth(const struct ieee80211_freq_range *freq_range,
 	return 0;
 }
 
+/* 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)
@@ -468,6 +606,10 @@ void wiphy_update_regulatory(struct wiphy *wiphy, enum reg_set_by setby)
 	}
 }
 
+/* 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, enum reg_set_by set_by,
@@ -517,14 +659,8 @@ static int ignore_request(struct wiphy *wiphy, enum reg_set_by set_by,
 			return -EALREADY;
 		return 0;
 	case REGDOM_SET_BY_USER:
-		/*
-		 * If the user wants to override the AP's hint, we may
-		 * need to follow both and use the intersection. For now,
-		 * reject any such attempt (but we don't support country
-		 * IEs right now anyway.)
-		 */
 		if (last_request->initiator == REGDOM_SET_BY_COUNTRY_IE)
-			return -EOPNOTSUPP;
+			return REG_INTERSECT;
 		return 0;
 	}
 
@@ -536,10 +672,14 @@ int __regulatory_hint(struct wiphy *wiphy, enum reg_set_by set_by,
 		      const char *alpha2)
 {
 	struct regulatory_request *request;
+	bool intersect = false;
 	int r = 0;
 
 	r = ignore_request(wiphy, set_by, alpha2);
-	if (r)
+
+	if (r == REG_INTERSECT)
+		intersect = true;
+	else if (r)
 		return r;
 
 	switch (set_by) {
@@ -556,6 +696,7 @@ int __regulatory_hint(struct wiphy *wiphy, enum reg_set_by set_by,
 		request->alpha2[1] = alpha2[1];
 		request->initiator = set_by;
 		request->wiphy = wiphy;
+		request->intersect = intersect;
 
 		kfree(last_request);
 		last_request = request;
@@ -648,6 +789,7 @@ static void print_regdomain_info(const struct ieee80211_regdomain *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;
 	/* Some basic sanity checks first */
 
 	if (is_world_regdom(rd->alpha2)) {
@@ -697,6 +839,14 @@ static int __set_regdom(const struct ieee80211_regdomain *rd)
 		return -EOPNOTSUPP;
 	}
 
+	if (unlikely(last_request->intersect)) {
+		intersected_rd = regdom_intersect(rd, cfg80211_regdomain);
+		if (!intersected_rd)
+			return -EINVAL;
+		kfree(rd);
+		rd = intersected_rd;
+	}
+
 	/* Tada! */
 	cfg80211_regdomain = rd;