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--[[
Copyright (c) 2011-2015, Vsevolod Stakhov <vsevolod@highsecure.ru>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
]]--
-- A plugin that implements ratelimits using redis or kvstorage server
-- Default settings for limits, 1-st member is burst, second is rate and the third is numeric type
local settings = {
-- Limit for all mail per recipient (burst 100, rate 2 per minute)
to = {0, 0.033333333},
-- Limit for all mail per one source ip (burst 30, rate 1.5 per minute)
to_ip = {0, 0.025},
-- Limit for all mail per one source ip and from address (burst 20, rate 1 per minute)
to_ip_from = {0, 0.01666666667},
-- Limit for all bounce mail (burst 10, rate 2 per hour)
bounce_to = {0, 0.000555556},
-- Limit for bounce mail per one source ip (burst 5, rate 1 per hour)
bounce_to_ip = {0, 0.000277778},
-- Limit for all mail per user (authuser) (burst 20, rate 1 per minute)
user = {0, 0.01666666667}
}
-- Senders that are considered as bounce
local bounce_senders = {'postmaster', 'mailer-daemon', '', 'null', 'fetchmail-daemon', 'mdaemon'}
-- Do not check ratelimits for these senders
local whitelisted_rcpts = {'postmaster', 'mailer-daemon'}
local whitelisted_ip
local max_rcpt = 5
local redis_params
local ratelimit_symbol
-- Do not delay mail after 1 day
local max_delay = 24 * 3600
local rspamd_logger = require "rspamd_logger"
local rspamd_redis = require "rspamd_redis"
local upstream_list = require "rspamd_upstream_list"
local rspamd_util = require "rspamd_util"
local fun = require "fun"
--local dumper = require 'pl.pretty'.dump
--- Parse atime and bucket of limit
local function parse_limits(data)
local function parse_limit_elt(str)
local elts = rspamd_str_split(str, ':')
if not elts or #elts < 2 then
return {0, 0, 0}
else
local atime = tonumber(elts[1])
local bucket = tonumber(elts[2])
local ctime = atime
if elts[3] then
ctime = tonumber(elts[3])
end
if not ctime then
ctime = atime
end
return {atime,bucket,ctime}
end
end
return fun.iter(data):map(function(e)
if type(e) == 'string' then
return parse_limit_elt(e)
else
return {0, 0, 0}
end
end):totable()
end
local function generate_format_string(args, is_set)
if is_set then
return 'MSET'
--return fun.foldl(function(acc, k) return acc .. ' %s %s' end, 'MSET', args)
end
return 'MGET'
--return fun.foldl(function(acc, k) return acc .. ' %s' end, 'MGET', args)
end
--- Check specific limit inside redis
local function check_limits(task, args)
local key = fun.foldl(function(acc, k) return acc .. k[2] end, '', args)
local ret,upstream
--- Called when value is got from server
local function rate_get_cb(task, err, data)
if data then
local ntime = rspamd_util.get_time()
fun.each(function(elt, limit)
local bucket = elt[2]
local rate = limit[2]
local threshold = limit[1]
local atime = elt[1]
local ctime = elt[3]
if atime == 0 then return end
if atime - ctime > max_delay then
rspamd_logger.infox(task, 'limit is too old: %1 seconds; ignore it',
atime - ctime)
else
bucket = bucket - rate * (ntime - atime);
if bucket > 0 then
if ratelimit_symbol then
local mult = 2 * rspamd_util.tanh(bucket / (threshold * 2))
if mult > 0.5 then
task:insert_result(ratelimit_symbol, mult,
tostring(mult))
end
else
if bucket > threshold then
task:set_pre_result('soft reject', 'Ratelimit exceeded')
end
end
end
end
end, fun.zip(parse_limits(data), fun.map(function(a) return a[1] end, args)))
elseif err then
rspamd_logger.infox(task, 'got error while getting limit: %1', err)
upstream:fail()
end
end
local cmd = generate_format_string(args, false)
ret,_,upstream = rspamd_redis_make_request(task,
redis_params, -- connect params
key, -- hash key
false, -- is write
rate_get_cb, --callback
cmd, -- command
fun.totable(fun.map(function(l) return l[2] end, args)) -- arguments
)
end
--- Set specific limit inside redis
local function set_limits(task, args)
local key = fun.foldl(function(acc, k) return acc .. k[2] end, '', args)
local ret, upstream
local function rate_set_cb(task, err, data)
if data then
local ntime = rspamd_util.get_time()
local values = {}
fun.each(function(elt, limit)
local bucket = elt[2]
local rate = limit[1][2]
local threshold = limit[1][1]
local atime = elt[1]
local ctime = elt[3]
if atime - ctime > max_delay then
rspamd_logger.infox(task, 'limit is too old: %1 seconds; start it over',
atime - ctime)
bucket = 1
ctime = ntime
atime = ntime
else
if bucket > 0 then
bucket = bucket - rate * (ntime - atime) + 1;
if bucket < 0 then
bucket = 1
end
else
bucket = 1
end
end
if ctime == 0 then ctime = ntime end
local lstr = string.format('%.3f:%.3f:%.3f', ntime, bucket, ctime)
table.insert(values, {limit[2], max_delay, lstr})
end, fun.zip(parse_limits(data), fun.iter(args)))
local conn = rspamd_redis.connect({
task = task,
host = upstream:get_addr()
})
if conn then
fun.each(function(v)
conn:add_cmd('setex', v)
end, values)
else
rspamd_logger.infox(task, 'got error while connecting to redis: %1', addr)
upstream:fail()
end
elseif err then
rspamd_logger.infox(task, 'got error while setting limit: %1', err)
upstream:fail()
end
end
local cmd = generate_format_string(args, false)
ret,_,upstream = rspamd_redis_make_request(task,
redis_params, -- connect params
key, -- hash key
true, -- is write
rate_set_cb, --callback
cmd, -- command
fun.totable(fun.map(function(l) return l[2] end, args)) -- arguments
)
end
--- Make rate key
local function make_rate_key(from, to, ip)
if from and ip and ip:is_valid() then
return string.format('%s:%s:%s', from, to, ip:to_string())
elseif from then
return string.format('%s:%s', from, to)
elseif ip and ip:is_valid() then
return string.format('%s:%s', to, ip:to_string())
elseif to then
return to
else
return nil
end
end
--- Check whether this addr is bounce
local function check_bounce(from)
return fun.any(function(b) return b == from end, bounce_senders)
end
--- Check or update ratelimit
local function rate_test_set(task, func)
local args = {}
-- Get initial task data
local ip = task:get_from_ip()
if ip and ip:is_valid() and whitelisted_ip then
if whitelisted_ip:get_key(ip) then
-- Do not check whitelisted ip
rspamd_logger.infox(task, 'skip ratelimit for whitelisted IP')
return
end
end
-- Parse all rcpts
local rcpts = task:get_recipients()
local rcpts_user = {}
if rcpts then
fun.each(function(r) table.insert(rcpts_user, r['user']) end, rcpts)
if fun.any(function(r)
fun.any(function(w) return r == w end, whitelisted_rcpts) end,
rcpts_user) then
rspamd_logger.infox(task, 'skip ratelimit for whitelisted recipient')
return
end
end
-- Parse from
local from = task:get_from()
local from_user = '<>'
local from_addr = '<>'
if from and from[1] and from[1]['addr'] then
from_user = from[1]['user']
from_addr = from[1]['addr']
end
-- Get user (authuser)
local auser = task:get_user()
if auser and settings['user'][1] > 0 then
table.insert(args, {settings['user'], make_rate_key (auser, '<auth>', nil)})
end
local is_bounce = check_bounce(from_user)
if rcpts and not auser then
fun.each(function(r)
if is_bounce then
if settings['bounce_to'][1] > 0 then
table.insert(args, { settings['bounce_to'], make_rate_key('<>', r['addr'], nil) })
end
if ip and settings['bounce_to_ip'][1] > 0 then
table.insert(args, { settings['bounce_to_ip'], make_rate_key('<>', r['addr'], ip) })
end
end
if settings['to'][1] > 0 then
table.insert(args, { settings['to'], make_rate_key(nil, r['addr'], nil) })
end
if ip then
if settings['to_ip'][1] > 0 then
table.insert(args, { settings['to_ip'], make_rate_key(nil, r['addr'], ip) })
end
if settings['to_ip_from'][1] > 0 then
table.insert(args, { settings['to_ip_from'], make_rate_key(from_addr, r['addr'], ip) })
end
end
end, rcpts)
end
if #args > 0 then
func(task, args)
end
end
--- Check limit
local function rate_test(task)
rate_test_set(task, check_limits)
end
--- Update limit
local function rate_set(task)
rate_test_set(task, set_limits)
end
--- Parse a single limit description
local function parse_limit(str)
local params = rspamd_str_split(str, ':')
local function set_limit(limit, burst, rate)
limit[1] = tonumber(burst)
limit[2] = tonumber(rate)
end
if table.maxn(params) ~= 3 then
rspamd_logger.errx(rspamd_config, 'invalid limit definition: ' .. str)
return
end
if params[1] == 'to' then
set_limit(settings['to'], params[2], params[3])
elseif params[1] == 'to_ip' then
set_limit(settings['to_ip'], params[2], params[3])
elseif params[1] == 'to_ip_from' then
set_limit(settings['to_ip_from'], params[2], params[3])
elseif params[1] == 'bounce_to' then
set_limit(settings['bounce_to'], params[2], params[3])
elseif params[1] == 'bounce_to_ip' then
set_limit(settings['bounce_to_ip'], params[2], params[3])
elseif params[1] == 'user' then
set_limit(settings['user'], params[2], params[3])
else
rspamd_logger.errx(rspamd_config, 'invalid limit type: ' .. params[1])
end
end
local opts = rspamd_config:get_all_opt('ratelimit')
if opts then
local rates = opts['limit']
if rates and type(rates) == 'table' then
fun.each(parse_limit, rates)
elseif rates and type(rates) == 'string' then
parse_limit(rates)
end
if opts['rates'] and type(opts['rates']) == 'table' then
-- new way of setting limits
fun.each(function(t, lim)
if type(lim) == 'table' and settings[t] then
settings[t] = lim
else
rspamd_logger.errx(rspamd_config, 'bad rate: %s: %s', t, lim)
end
end, opts['rates'])
end
local enabled_limits = fun.totable(fun.map(function(t, lim)
return t
end, fun.filter(function(t, lim) return lim[1] > 0 end, settings)))
rspamd_logger.infox(rspamd_config, 'enabled rate buckets: %s', enabled_limits)
if opts['whitelisted_rcpts'] and type(opts['whitelisted_rcpts']) == 'string' then
whitelisted_rcpts = rspamd_str_split(opts['whitelisted_rcpts'], ',')
elseif type(opts['whitelisted_rcpts']) == 'table' then
whitelisted_rcpts = opts['whitelisted_rcpts']
end
if opts['whitelisted_ip'] then
whitelisted_ip = rspamd_config:add_radix_map(opts['whitelisted_ip'], 'Ratelimit whitelist ip map')
end
if opts['symbol'] then
-- We want symbol instead of pre-result
ratelimit_symbol = opts['symbol']
end
if opts['max_rcpt'] then
max_rcpt = tonumber(opts['max_rcpt'])
end
if opts['max_delay'] then
max_rcpt = tonumber(opts['max_delay'])
end
redis_params = rspamd_parse_redis_server('ratelimit')
if not redis_params then
rspamd_logger.infox(rspamd_config, 'no servers are specified, disabling module')
else
if not ratelimit_symbol then
rspamd_config:register_pre_filter(rate_test)
else
rspamd_config:register_symbol({
name = ratelimit_symbol,
callback = rate_test,
flags = 'empty'
})
end
rspamd_config:register_post_filter(rate_set)
end
end
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