Class: DNSBL::Client

Inherits:
Object
  • Object
show all
Defined in:
lib/dnsbl/client.rb,
lib/dnsbl/client/version.rb

Overview

Client actually handles the sending of queries to a recursive DNS server and places any replies into DNSBLResults

Constant Summary collapse

VERSION =

Current version of the dnsbl-client gem

'1.1.1'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(config = YAML.safe_load(File.read("#{File.expand_path '../../data', __dir__}/dnsbl.yaml")), two_level_tldfile = "#{File.expand_path '../../data', __dir__}/two-level-tlds", three_level_tldfile = "#{File.expand_path '../../data', __dir__}/three-level-tlds") ⇒ Client

initialize a new DNSBL::Client object the config file automatically points to a YAML file containing the list of DNSBLs and their return codes the two-level-tlds file lists most of the two level tlds, needed for hostname to domain normalization



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# File 'lib/dnsbl/client.rb', line 54

def initialize(config = YAML.safe_load(File.read("#{File.expand_path '../../data', __dir__}/dnsbl.yaml")),
               two_level_tldfile = "#{File.expand_path '../../data', __dir__}/two-level-tlds",
               three_level_tldfile = "#{File.expand_path '../../data', __dir__}/three-level-tlds")
  @dnsbls = config
  @timeout = 1.5
  @first_only = false
  @two_level_tld = []
  @three_level_tld = []
  File.open(two_level_tldfile).readlines.each do |l|
    @two_level_tld << l.strip
  end
  File.open(three_level_tldfile).readlines.each do |l|
    @three_level_tld << l.strip
  end
  @sockets = []
  config = Resolv::DNS::Config.new

  # let's just the first nameserver in this version of the library
  ip, port = config.nameservers.first

  sock = UDPSocket.new
  sock.connect ip, port
  @sockets << sock
  @socket_index = 0
end

Instance Attribute Details

#first_only=(value) ⇒ Object (writeonly)

Sets the attribute first_only

Parameters:

  • value —

    the value to set the attribute first_only to.



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# File 'lib/dnsbl/client.rb', line 48

def first_only=(value)
  @first_only = value
end

#timeout=(value) ⇒ Object (writeonly)

Sets the attribute timeout

Parameters:

  • value —

    the value to set the attribute timeout to.



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# File 'lib/dnsbl/client.rb', line 48

def timeout=(value)
  @timeout = value
end

Instance Method Details

#add_dnsbl(name, domain, type = 'ip', codes = { '0' => 'OK', '127.0.0.2' => 'Blacklisted' }) ⇒ Object

allows the adding of a new DNSBL to the set of configured DNSBLs



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# File 'lib/dnsbl/client.rb', line 108

def add_dnsbl(name, domain, type = 'ip', codes = { '0' => 'OK', '127.0.0.2' => 'Blacklisted' })
  @dnsbls[name] = codes
  @dnsbls[name]['domain'] = domain
  @dnsbls[name]['type'] = type
end

#dnsbls ⇒ Object

returns a list of DNSBL names currently configured



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# File 'lib/dnsbl/client.rb', line 115

def dnsbls
  @dnsbls.keys
end

#lookup(loopup_item) ⇒ Object

lookup performs the sending of DNS queries for the given items returns an array of DNSBLResult



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# File 'lib/dnsbl/client.rb', line 121

def lookup(loopup_item)
  # if item is an array, use it, otherwise make it one
  items = Array loopup_item

  # place the results in the results array
  results = []
  # for each ip or hostname
  items.each do |item|
    # sent is used to determine when we have all the answers
    sent = 0
    # record the start time
    @starttime = Time.now.to_f
    # determine the type of query
    itemtype = item.match?(/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/) ? 'ip' : 'domain'
    if item.match?(/^\s*((([0-9A-Fa-f]{1,4}:){7}([0-9A-Fa-f]{1,4}|:))|(([0-9A-Fa-f]{1,4}:){6}(:[0-9A-Fa-f]{1,4}|((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3})|((:[0-9A-Fa-f]{1,4})?:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){1,4})|((:[0-9A-Fa-f]{1,4}){0,2}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5})|((:[0-9A-Fa-f]{1,4}){0,3}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){1,6})|((:[0-9A-Fa-f]{1,4}){0,4}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(:(((:[0-9A-Fa-f]{1,4}){1,7})|((:[0-9A-Fa-f]{1,4}){0,5}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:)))(%.+)?\s*$/) # rubocop: disable Layout/LineLength
      itemtype = 'ip'
    end

    # for each dnsbl that supports our type, create the DNS query packet and send it
    # rotate across our configured name servers and increment sent
    @dnsbls.each do |name, config|
      next if config['disabled']
      next unless config['type'] == itemtype

      begin
        msg = encode_query item, itemtype, config['domain'], config['apikey']
        @sockets[@socket_index].send msg, 0
        @socket_index += 1
        @socket_index %= @sockets.length
        sent += 1
      rescue StandardError => e
        puts "error for #{name}: e"
        puts e.backtrace.join("\n")
      end
    end

    # while we still expect answers
    while sent.positive?
      # wait on the socket for maximally @timeout seconds
      r, = IO.select @sockets, nil, nil, @timeout
      # if we time out, break out of the loop
      break unless r

      # for each reply, decode it and receive results, decrement the pending answers
      first_only = false
      r.each do |s|
        begin
          response = decode_response(s.recv(4096))
          results += response
        rescue StandardError => e
          puts e
          puts e.backtrace.join("\n")
        end
        sent -= 1
        if @first_only
          first_only = true
          break
        end
      end
      break if first_only
    end
  end
  results
end

#nameservers=(nss = Resolv::DNS::Config.new.nameservers) ⇒ Object

sets the nameservers used for performing DNS lookups in round-robin fashion



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# File 'lib/dnsbl/client.rb', line 81

def nameservers=(nss = Resolv::DNS::Config.new.nameservers)
  @sockets.each(&:close)
  @sockets = []

  # let's just the first nameserver in this version of the library
  ip, port = nss.first

  sock = UDPSocket.new
  sock.connect ip, port
  @sockets << sock
  @socket_index = 0
end

#normalize(domain) ⇒ Object

Converts a hostname to the domain: e.g., www.google.com => google.com, science.somewhere.co.uk => somewhere.co.uk



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# File 'lib/dnsbl/client.rb', line 95

def normalize(domain)
  # strip off the protocol (\w{1,20}://), the URI (/), parameters (?), port number (:), and username (.*@)
  # then split into parts via the .
  parts = domain.gsub(%r{^\w{1,20}://}, '').gsub(%r{[/?:].*}, '').gsub(/.*?@/, '').split('.')
  # grab the last two parts of the domain
  dom = parts[-2, 2].join '.'
  # if the dom is in the two_level_tld list, then use three parts
  dom = parts[-3, 3].join '.' if @two_level_tld.index dom
  dom = parts[-4, 4].join '.' if @three_level_tld.index dom
  dom
end