-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local create_throttle = require "util.throttle".create;

local new_cache = require "util.cache".new;

local ip_util = require "util.ip";

local new_ip = ip_util.new_ip;

local match_ip = ip_util.match;

local parse_cidr = ip_util.parse_cidr;

local errors = require "util.error";

local min_seconds_between_registrations = module:get_option_number("min_seconds_between_registrations");

local whitelist_only = module:get_option_boolean("whitelist_registration_only");

local whitelisted_ips = module:get_option_set("registration_whitelist", { "127.0.0.1", "::1" })._items;

local blacklisted_ips = module:get_option_set("registration_blacklist", {})._items;

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

local function ip_in_set(set, ip)

	if set[ip] then

		return true;

	end

	ip = new_ip(ip);

	for in_set in pairs(set) do

		if match_ip(ip, parse_cidr(in_set)) then

			return true;

		end

	end

	return false;

end

local err_registry = {

	blacklisted = {

		text = "Your IP address is blacklisted";

		type = "auth";

		condition = "forbidden";

	};

	not_whitelisted = {

		text = "Your IP address is not whitelisted";

		type = "auth";

		condition = "forbidden";

	};

	throttled = {

		reason = "Too many registrations from this IP address recently";

		type = "wait";

		condition = "policy-violation";

	};

}

module:hook("user-registering", function (event)

	local session = event.session;

	local ip = event.ip or session and session.ip;

	local log = session and session.log or module._log;

	if not ip then

		log("warn", "IP not known; can't apply blacklist/whitelist");

	elseif ip_in_set(blacklisted_ips, ip) then

		log("debug", "Registration disallowed by blacklist");

		event.allowed = false;

		event.error = errors.new("blacklisted", event, err_registry);

	elseif (whitelist_only and not ip_in_set(whitelisted_ips, ip)) then

		log("debug", "Registration disallowed by whitelist");

		event.allowed = false;

		event.error = errors.new("not_whitelisted", event, err_registry);

	elseif throttle_max and not ip_in_set(whitelisted_ips, ip) then

		if not check_throttle(ip) then

			log("debug", "Registrations over limit for ip %s", ip or "?");

			event.allowed = false;

		end

	end

	if event.error then

		-- COMPAT pre-util.error

		event.reason = event.error.text;

		event.error_type = event.error.type;

		event.error_condition = event.error.condition;

	end

end);