+local throttle_max = module:get_option_number("registration_throttle_max", min_seconds_between_registrations and 1);
+local throttle_period = module:get_option_number("registration_throttle_period", min_seconds_between_registrations);
+local throttle_cache_size = module:get_option_number("registration_throttle_cache_size", 100);
+local blacklist_overflow = module:get_option_boolean("blacklist_on_registration_throttle_overload", false);
+
+local throttle_cache = new_cache(throttle_cache_size, blacklist_overflow and function (ip, throttle)
+ if not throttle:peek() then
+ module:log("info", "Adding ip %s to registration blacklist", ip);
+ blacklisted_ips[ip] = true;
+ end
+end or nil);
+
+local function check_throttle(ip)
+ if not throttle_max then return true end
+ local throttle = throttle_cache:get(ip);
+ if not throttle then
+ throttle = create_throttle(throttle_max, throttle_period);
+ end
+ throttle_cache:set(ip, throttle);
+ return throttle:poll(1);
+end
+