Update WisunBorderRouter class

Add set_dns_query_result to WisunBorderRouter.

Author: Arto Kinnunen

connectivity/nanostack/mbed-mesh-api/mbed-mesh-api/WisunBorderRouter.h

@@ -307,6 +307,19 @@ class WisunBorderRouter {
      * */
     mesh_error_t validate_radius_timing(ws_br_radius_timing_t *timing);
 
+    /**
+     * \brief Set DNS query result to Nanostack cache.
+     *
+     * Function sets DNS query result to Nanostack cache to get distributed to the devices in the Wi-SUN network.
+     * Function must be called for a running Wi-SUN Border Router instance.
+     *
+     * \param address resolved address of domain_name.
+     * \param domain_name name of the domain. Must be non-NULL.
+     * \return MESH_ERROR_NONE on success.
+     * \return error value in case of failure.
+     * */
+    mesh_error_t set_dns_query_result(SocketAddress *address, char *domain_name);
+
 private:
     mesh_error_t configure();
     mesh_error_t apply_configuration(int8_t mesh_if_id);

connectivity/nanostack/mbed-mesh-api/source/WisunBorderRouter.cpp

@@ -452,3 +452,20 @@ mesh_error_t WisunBorderRouter::validate_radius_timing(ws_br_radius_timing_t *ti
 
     return MESH_ERROR_NONE;
 }
+
+mesh_error_t WisunBorderRouter::set_dns_query_result(SocketAddress *address, char *domain_name)
+{
+    if (!domain_name || !address) {
+        return MESH_ERROR_PARAM;
+    }
+
+    if (_mesh_if_id < 0) {
+        return MESH_ERROR_STATE;
+    }
+
+    if (ws_bbr_dns_query_result_set(_mesh_if_id, (const uint8_t *)address->get_ip_bytes(), domain_name) >= 0 ) {
+        return MESH_ERROR_NONE;
+    }
+
+    return MESH_ERROR_UNKNOWN;
+}