1 files changed, 158 insertions, 8 deletions

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 34983a825ac1..3f18a1d03a55 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;