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--[[
Copyright (c) 2016, Steve Freegard <steve.freegard@fsl.com>
Copyright (c) 2016, Vsevolod Stakhov
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.
]]--
-- Check messages for 'bulkiness' using DCC
local N = 'dcc'
local symbol_bulk = "DCC_BULK"
local opts = rspamd_config:get_all_opt(N)
local rspamd_logger = require "rspamd_logger"
local lua_util = require "lua_util"
local tcp = require "rspamd_tcp"
local upstream_list = require "rspamd_upstream_list"
local fun = require "fun"
if confighelp then
rspamd_config:add_example(nil, 'dcc',
"Check messages for 'bulkiness' using DCC",
[[
dcc {
socket = "/var/dcc/dccifd"; # Unix socket
servers = "127.0.0.1:10045" # OR TCP upstreams
timeout = 2s; # Timeout to wait for checks
}
]])
return
end
local function check_dcc (task)
-- Connection
local client = '0.0.0.0'
local client_ip = task:get_from_ip()
local dcc_upstream
local upstream
local addr
local port
local retransmits = 2
if opts['servers'] then
dcc_upstream = upstream_list.create(rspamd_config, opts['servers'])
upstream = dcc_upstream:get_upstream_round_robin()
addr = upstream:get_addr()
port = addr:get_port()
else
lua_util.debugm(N, task, 'using socket %s', opts['socket'])
addr = opts['socket']
end
if client_ip and client_ip:is_valid() then
client = client_ip:to_string()
end
local client_host = task:get_hostname()
if client_host then
client = client .. "\r" .. client_host
end
-- HELO
local helo = task:get_helo() or ''
-- Envelope From
local ef = task:get_from()
local envfrom = 'test@example.com'
if ef and ef[1] then
envfrom = ef[1]['addr']
end
-- Envelope To
local envrcpt = 'test@example.com'
local rcpts = task:get_recipients();
if rcpts then
local r = table.concat(fun.totable(fun.map(function(rcpt)
return rcpt['addr'] end,
rcpts)), '\n')
if r then
envrcpt = r
end
end
-- Callback function to receive async result from DCC
local function cb(err, data)
if err then
if retransmits > 0 then
retransmits = retransmits - 1
-- Select a different upstream or the socket again
if opts['servers'] then
upstream = dcc_upstream:get_upstream_round_robin()
addr = upstream:get_addr()
port = addr:get_port()
else
addr = opts['socket']
end
lua_util.debugm(N, task, "sending query to %s:%s",tostring(addr), port)
data = {
"header\n",
client .. "\n",
helo .. "\n",
envfrom .. "\n",
envrcpt .. "\n",
"\n",
task:get_content()
}
tcp.request({
task = task,
host = tostring(addr),
port = port or 1,
timeout = opts['timeout'] or 2.0,
shutdown = true,
data = data,
callback = cb
})
else
rspamd_logger.errx(task, 'failed to scan, maximum retransmits exceed')
upstream:fail()
end
else
-- Parse the response
local _,_,result,disposition,header = tostring(data):find("(.-)\n(.-)\n(.-)\n")
lua_util.debugm(N, task, 'DCC result=%1 disposition=%2 header="%3"',
result, disposition, header)
if header then
local _,_,info = header:find("; (.-)$")
if (result == 'R') then
-- Reject
task:insert_result(symbol_bulk, 1.0, info)
elseif (result == 'T') then
-- Temporary failure
rspamd_logger.warnx(task, 'DCC returned a temporary failure result')
else
if result ~= 'A' and result ~= 'G' and result ~= 'S' then
-- Unknown result
rspamd_logger.warnx(task, 'DCC result error: %1', result);
end
end
end
end
end
-- Build the DCC query
-- https://www.dcc-servers.net/dcc/dcc-tree/dccifd.html#Protocol
local data = {
"header\n",
client .. "\n",
helo .. "\n",
envfrom .. "\n",
envrcpt .. "\n",
"\n",
task:get_content()
}
rspamd_logger.warnx(task, "sending to %s:%s",tostring(addr), port)
tcp.request({
task = task,
host = tostring(addr),
port = port or 1,
timeout = opts['timeout'] or 2.0,
shutdown = true,
data = data,
callback = cb
})
end
-- Configuration
-- WORKAROUND for deprecated host and port settings
if opts['host'] ~= nil and opts['port'] ~= nil then
opts['servers'] = opts['host'] .. ':' .. opts['port']
rspamd_logger.warnx(rspamd_config, 'Using host and port parameters is deprecated. '..
'Please use servers = "%s:%s"; instead', opts['host'], opts['port'])
end
if opts['host'] ~= nil and not opts['port'] then
opts['socket'] = opts['host']
rspamd_logger.warnx(rspamd_config, 'Using host parameters is deprecated. '..
'Please use socket = "%s"; instead', opts['host'])
end
-- WORKAROUND for deprecated host and port settings
if opts and ( opts['servers'] or opts['socket'] ) then
rspamd_config:register_symbol({
name = symbol_bulk,
callback = check_dcc
})
rspamd_config:set_metric_symbol({
group = N,
score = 2.0,
description = 'Detected as bulk mail by DCC',
one_shot = true,
name = symbol_bulk
})
else
lua_util.disable_module(N, "config")
rspamd_logger.infox('DCC module not configured');
end
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