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--[[
Copyright (c) 2011-2015, Vsevolod Stakhov <vsevolod@highsecure.ru>
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
]]--
-- A plugin that implements ratelimits using redis or kvstorage server
-- Default port for redis upstreams
local default_port = 6379
-- 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 upstreams
local ratelimit_symbol
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 _ = 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 pos,_ = string.find(str, ':')
if not pos then
return {0, 0}
else
local atime = tonumber(string.sub(str, 1, pos - 1))
local bucket = tonumber(string.sub(str, pos + 1))
return {atime,bucket}
end
end
return _.iter(data):map(function(e)
if type(e) == 'string' then
return parse_limit_elt(e)
else
return {0, 0}
end
end):totable()
end
local function generate_format_string(args, is_set)
if is_set then
return 'MSET'
--return _.foldl(function(acc, k) return acc .. ' %s %s' end, 'MSET', args)
end
return 'MGET'
--return _.foldl(function(acc, k) return acc .. ' %s' end, 'MGET', args)
end
--- Check specific limit inside redis
local function check_limits(task, args)
local key = _.foldl(function(acc, k) return acc .. k[2] end, '', args)
local upstream = upstreams:get_upstream_by_hash(key)
local addr = upstream:get_addr()
--- Called when value was set on server
local function rate_set_key_cb(task, err, data)
if err then
rspamd_logger.infox(task, 'got error while getting limit: %1', err)
upstream:fail()
else
upstream:ok()
end
end
--- Called when value is got from server
local function rate_get_cb(task, err, data)
if data then
local tv = task:get_timeval()
local ntime = tv['tv_usec'] / 1000000. + tv['tv_sec']
_.each(function(elt, limit)
local bucket = elt[2]
local rate = limit[2]
local threshold = limit[1]
local atime = elt[1]
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, _.zip(parse_limits(data), _.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
if upstream then
local cmd = generate_format_string(args, false)
rspamd_redis.make_request(task, addr, rate_get_cb, cmd,
_.totable(_.map(function(l) return l[2] end, args)))
end
end
--- Set specific limit inside redis
local function set_limits(task, args)
local key = _.foldl(function(acc, k) return acc .. k[2] end, '', args)
local upstream = upstreams:get_upstream_by_hash(key)
local addr = upstream:get_addr()
local function rate_set_key_cb(task, err, data)
if err then
rspamd_logger.infox(task, 'got error while setting limit: %1', err)
upstream:fail()
else
upstream:ok()
end
end
local function rate_set_cb(task, err, data)
if data then
local tv = task:get_timeval()
local ntime = tv['tv_usec'] / 1000000. + tv['tv_sec']
local values = {}
_.each(function(elt, limit)
local bucket = elt[2]
local rate = limit[1][2]
local threshold = limit[1][1]
local atime = elt[1]
if bucket > 0 then
bucket = bucket - rate * (ntime - atime) + 1;
if bucket < 0 then
bucket = 1
end
else
bucket = 1
end
local lstr = string.format('%.3f:%.3f', ntime, bucket)
table.insert(values, limit[2])
table.insert(values, lstr)
end, _.zip(parse_limits(data), _.iter(args)))
local cmd = generate_format_string(values, true)
rspamd_redis.make_request(task, addr, rate_set_key_cb, cmd, values)
elseif err then
rspamd_logger.infox(task, 'got error while setting limit: %1', err)
upstream:fail()
end
end
if upstream then
local cmd = generate_format_string(args, false)
rspamd_redis.make_request(task, addr, rate_set_cb, cmd,
_.totable(_.map(function(l) return l[2] end, args)))
end
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 _.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
_.each(function(r) table.insert(rcpts_user, r['user']) end, rcpts)
if _.any(function(r)
_.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'] > 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
_.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
--- Utility function for split string to table
local function split(str, delim, maxNb)
-- Eliminate bad cases...
if string.find(str, delim) == nil then
return { str }
end
if maxNb == nil or maxNb < 1 then
maxNb = 0 -- No limit
end
local result = {}
local pat = "(.-)" .. delim .. "()"
local nb = 0
local lastPos
for part, pos in string.gmatch(str, pat) do
nb = nb + 1
result[nb] = part
lastPos = pos
if nb == maxNb then break end
end
-- Handle the last field
if nb ~= maxNb then
result[nb + 1] = string.sub(str, lastPos)
end
return result
end
--- Parse a single limit description
local function parse_limit(str)
local params = split(str, ':', 0)
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
_.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
_.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 = _.totable(_.map(function(t, lim)
return t
end, _.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 = 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 not opts['servers'] then
rspamd_logger.infox(rspamd_config, 'no servers are specified, disabling module')
else
upstreams = upstream_list.create(rspamd_config, opts['servers'], default_port)
if not upstreams 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(ratelimit_symbol, 1.0, rate_test)
end
rspamd_config:register_post_filter(rate_set)
end
end
end
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