--[[
Copyright (c) 2011-2016, Vsevolod Stakhov <vsevolod@highsecure.ru>
Copyright (c) 2016, Andrew Lewis <nerf@judo.za.org>

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.
]]--

local rspamd_logger = require "rspamd_logger"
local rspamd_regexp = require "rspamd_regexp"

local options = {
  provider_type = 'cymru',
  provider_info = {
    ip4 = 'origin.asn.cymru.com',
    ip6 = 'origin6.asn.cymru.com',
  },
  symbol = 'ASN',
}

local cymru_re = rspamd_regexp.create_cached("[\\|\\s]")

local function asn_check(task)

  local function asn_set(asn, ipnet, country)
    local descr_t = {}
    if asn then
      task:get_mempool():set_variable("asn", asn)
      table.insert(descr_t, "asn:" .. asn)
    end
    if ipnet then
      task:get_mempool():set_variable("ipnet", ipnet)
      table.insert(descr_t, "ipnet:" .. ipnet)
    end
    if country then
      task:get_mempool():set_variable("country", country)
      table.insert(descr_t, "country:" .. country)
    end
    if options['symbol'] then
      task:insert_result(options['symbol'], 0.0, table.concat(descr_t, ', '))
    end
  end

  local asn_check_func = {}
  function asn_check_func.cymru(ip)
    local function cymru_dns_cb(resolver, to_resolve, results, err, key)
      if not (results and results[1]) then return end
      local parts = cymru_re:split(results[1])
      -- "15169 | 8.8.8.0/24 | US | arin |" for 8.8.8.8
      asn_set(parts[1], parts[2], parts[3])
    end
    local dnsbl = options['provider_info']['ip' .. ip:get_version()]
    local req_name = rspamd_logger.slog("%1.%2",
        table.concat(ip:inversed_str_octets(), '.'), dnsbl)
    task:get_resolver():resolve_txt(task:get_session(), task:get_mempool(),
        req_name, cymru_dns_cb)
  end

  local ip = task:get_from_ip()
  if not (ip and ip:is_valid()) then return end
  asn_check_func[options['provider_type']](ip)
end

-- Configuration options
local configure_asn_module = function()
  local opts =  rspamd_config:get_all_opt('asn')
  if opts then
    for k,v in pairs(opts) do
      options[k] = v
    end
  end
  if options['provider_type'] == 'cymru' then
    if not options['provider_info'] and options['provider_info']['ip4'] and
        options['provider_info']['ip6'] then
      rspamd_logger.errx("Missing required provider_info for cymru")
      return false
    end
  else
    rspamd_logger.errx("Unknown provider_type: %s", options['provider_type'])
    return false
  end
  return true
end

if configure_asn_module() then
  rspamd_config:register_symbol({
    name = 'ASN_CHECK',
    type = 'prefilter',
    callback = asn_check,
    priority = 10,
  })
end