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# -*- coding: binary -*-
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module Msf
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module Ui
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module Console
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module CommandDispatcher
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class DNS
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10
  include Msf::Ui::Console::CommandDispatcher
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  ADD_USAGE = 'dns [add] [--index <insertion index>] [--rule <wildcard DNS entry>] [--session <session id>] <resolver> ...'.freeze
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  @@add_opts = Rex::Parser::Arguments.new(
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    ['-i', '--index'] => [true, 'Index to insert at'],
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    ['-r', '--rule'] => [true, 'Set a DNS wildcard entry to match against'],
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    ['-s', '--session'] => [true, 'Force the DNS request to occur over a particular channel (override routing rules)']
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  )
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  ADD_STATIC_USAGE = 'dns [add-static] <hostname> <IP address> ...'.freeze
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  REMOVE_USAGE = 'dns [remove/del] -i <entry id> [-i <entry id> ...]'.freeze
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  @@remove_opts = Rex::Parser::Arguments.new(
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    ['-i', '--index'] => [true, 'Index to remove at']
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  )
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  REMOVE_STATIC_USAGE = 'dns [remove-static] <hostname> [<IP address> ...]'.freeze
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  RESET_CONFIG_USAGE = 'dns [reset-config] [-y/--yes] [--system]'.freeze
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  @@reset_config_opts = Rex::Parser::Arguments.new(
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    ['-y', '--yes'] => [false, 'Assume yes and do not prompt for confirmation before resetting'],
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    ['--system'] => [false, 'Include the system resolver']
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  )
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  RESOLVE_USAGE = 'dns [resolve] [-f <address family>] <hostname> ...'.freeze
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  @@resolve_opts = Rex::Parser::Arguments.new(
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    # same usage syntax as Rex::Post::Meterpreter::Ui::Console::CommandDispatcher::Stdapi
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    ['-f'] => [true,  'Address family - IPv4 or IPv6 (default IPv4)']
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  )
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  def initialize(driver)
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    super
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  end
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  def name
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    'DNS'
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  end
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  def commands
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    commands = {}
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    if framework.features.enabled?(Msf::FeatureManager::DNS)
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      commands = {
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        'dns' => "Manage Metasploit's DNS resolving behaviour"
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      }
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    end
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    commands
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  end
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  #
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  # Tab completion for the dns command
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  #
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  # @param str [String] the string currently being typed before tab was hit
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  # @param words [Array<String>] the previously completed words on the command line. The array
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  # contains at least one entry when tab completion has reached this stage since the command itself has been completed
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  def cmd_dns_tabs(str, words)
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    return if driver.framework.dns_resolver.nil?
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    subcommands = %w[ add add-static delete flush-cache flush-entries flush-static help print query remove remove-static reset-config resolve ]
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    if words.length == 1
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      return subcommands.select { |opt| opt.start_with?(str) }
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    end
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    cmd = words[1]
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    case cmd
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    when 'add'
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      # We expect a repeating pattern of tag (e.g. -r) and then a value (e.g. *.metasploit.com)
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      # Once this pattern is violated, we're just specifying DNS servers at that point.
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      tag_is_expected = true
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      if words.length > 2
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        words[2..-1].each do |word|
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          if tag_is_expected && !word.start_with?('-')
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            return
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          end
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          tag_is_expected = !tag_is_expected
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        end
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      end
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      case words[-1]
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      when '-r', '--rule'
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        # Hard to auto-complete a rule with any meaningful value; just return
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        return
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      when '-s', '--session'
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        session_ids = driver.framework.sessions.keys.map { |k| k.to_s }
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        return session_ids.select { |id| id.start_with?(str) }
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      when /^-/
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        # Unknown tag
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        return
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      end
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      options = @@add_opts.option_keys.select { |opt| opt.start_with?(str) }
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      options << '' # Prevent tab-completion of a dash, given they could provide an IP address at this point
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      return options
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    when 'add-static'
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      if words.length == 2
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        # tab complete existing hostnames because they can have more than one IP address
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        return resolver.static_hostnames.each.select { |hostname,_| hostname.downcase.start_with?(str.downcase) }.map { |hostname,_| hostname }
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      end
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    when 'help'
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      # These commands don't have any arguments
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      return subcommands.select { |sc| sc.start_with?(str) }
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    when 'remove','delete'
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      if words[-1] == '-i'
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        return
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      else
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        return @@remove_opts.option_keys.select { |opt| opt.start_with?(str) }
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      end
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    when 'remove-static'
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      if words.length == 2
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        return resolver.static_hostnames.each.select { |hostname,_| hostname.downcase.start_with?(str.downcase) }.map { |hostname,_| hostname }
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      elsif words.length > 2
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        hostname = words[2]
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        ip_addresses = resolver.static_hostnames.get(hostname, Dnsruby::Types::A) + resolver.static_hostnames.get(hostname, Dnsruby::Types::AAAA)
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        return ip_addresses.map(&:to_s).select { |ip_address| ip_address.start_with?(str) }
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      end
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    when 'reset-config'
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      @@reset_config_opts.option_keys.select { |opt| opt.start_with?(str) }
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    when 'resolve','query'
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      if words[-1] == '-f'
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        families = %w[ IPv4 IPv6 ] # The family argument is case-insensitive
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        return families.select { |family| family.downcase.start_with?(str.downcase) }
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      else
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        @@resolve_opts.option_keys.select { |opt| opt.start_with?(str) }
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      end
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    end
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  end
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137
  def cmd_dns_help(*args)
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    if args.first.present?
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      handler = "#{args.first.gsub('-', '_')}_dns"
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      if respond_to?("#{handler}_help")
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        # if it is a valid command with dedicated help information
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        return send("#{handler}_help")
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      elsif respond_to?(handler)
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        # if it is a valid command without dedicated help information
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        print_error("No help menu is available for #{args.first}")
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        return
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      else
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        print_error("Invalid subcommand: #{args.first}")
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      end
150
    end
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152
    print_line "Manage Metasploit's DNS resolution behaviour"
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    print_line
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    print_line "USAGE:"
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    print_line "  #{ADD_USAGE}"
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    print_line "  #{ADD_STATIC_USAGE}"
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    print_line "  #{REMOVE_USAGE}"
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    print_line "  #{REMOVE_STATIC_USAGE}"
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    print_line "  dns [flush-cache]"
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    print_line "  dns [flush-entries]"
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    print_line "  dns [flush-static]"
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    print_line "  dns [print]"
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    print_line "  #{RESET_CONFIG_USAGE}"
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    print_line "  #{RESOLVE_USAGE}"
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    print_line "  dns [help] [subcommand]"
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    print_line
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    print_line "SUBCOMMANDS:"
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    print_line "  add           - Add a DNS resolution entry to resolve certain domain names through a particular DNS resolver"
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    print_line "  add-static    - Add a statically defined hostname"
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    print_line "  flush-cache   - Remove all cached DNS answers"
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    print_line "  flush-entries - Remove all configured DNS resolution entries"
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    print_line "  flush-static  - Remove all statically defined hostnames"
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    print_line "  print         - Show all configured DNS resolution entries"
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    print_line "  remove        - Delete a DNS resolution entry"
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    print_line "  remove-static - Delete a statically defined hostname"
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    print_line "  reset-config  - Reset the DNS configuration"
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    print_line "  resolve       - Resolve a hostname"
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    print_line
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    print_line "EXAMPLES:"
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    print_line "  Display help information for the 'add' subcommand"
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    print_line "    dns help add"
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    print_line
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  end
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  #
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  # Manage Metasploit's DNS resolution rules
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  #
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  def cmd_dns(*args)
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    if driver.framework.dns_resolver.nil?
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      print_warning("Run the #{Msf::Ui::Tip.highlight("save")} command and restart the console for this feature configuration to take effect.")
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      return
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    end
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194
    args << 'print' if args.length == 0
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    # Short-circuit help
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    if args.delete("-h") || args.delete("--help")
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      subcommand = args.first
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      if subcommand && respond_to?("#{subcommand.gsub('-', '_')}_dns_help")
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        # if it is a valid command with dedicated help information
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        send("#{subcommand.gsub('-', '_')}_dns_help")
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      else
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        # otherwise print the top-level help information
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        cmd_dns_help
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      end
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      return
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    end
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208
    action = args.shift
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    begin
210
      case action
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      when "add"
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        add_dns(*args)
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      when "add-static"
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        add_static_dns(*args)
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      when "flush-entries"
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        flush_entries_dns
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      when "flush-cache"
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        flush_cache_dns
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      when "flush-static"
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        flush_static_dns
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      when "help"
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        cmd_dns_help(*args)
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      when "print"
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        print_dns
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      when "remove", "rm", "delete", "del"
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        remove_dns(*args)
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      when "remove-static"
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        remove_static_dns(*args)
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      when "reset-config"
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        reset_config_dns(*args)
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      when "resolve", "query"
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        resolve_dns(*args)
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      else
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        print_error("Invalid command. To view help: dns -h")
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      end
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    rescue ::ArgumentError => e
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      print_error(e.message)
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    end
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  end
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241
  def add_dns(*args)
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    rules = ['*']
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    first_rule = true
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    comm = nil
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    resolvers = []
246
    index = -1
247
    @@add_opts.parse(args) do |opt, idx, val|
248
      unless resolvers.empty? || opt.nil?
249
        raise ::ArgumentError.new("Invalid command near #{opt}")
250
      end
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      case opt
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      when '-i', '--index'
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        raise ::ArgumentError.new("Not a valid index: #{val}") unless val.to_i > 0
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255
        index = val.to_i - 1
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      when '-r', '--rule'
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        raise ::ArgumentError.new('No rule specified') if val.nil?
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259
        rules.clear if first_rule # if the user defines even one rule, clear the defaults
260
        first_rule = false
261
        rules << val
262
      when '-s', '--session'
263
        if val.nil?
264
          raise ::ArgumentError.new('No session specified')
265
        end
266

267
        unless comm.nil?
268
          raise ::ArgumentError.new('Only one session can be specified')
269
        end
270

271
        comm = val
272
      when nil
273
        val = 'black-hole' if val.casecmp?('blackhole')
274
        resolvers << val
275
      else
276
        raise ::ArgumentError.new("Unknown flag: #{opt}")
277
      end
278
    end
279

280
    # The remaining args should be the DNS servers
281
    if resolvers.length < 1
282
      raise ::ArgumentError.new('You must specify at least one upstream DNS resolver')
283
    end
284

285
    resolvers.each do |resolver|
286
      unless Rex::Proto::DNS::UpstreamRule.valid_resolver?(resolver)
287
        message = "Invalid DNS resolver: #{resolver}."
288
        if (suggestions = Rex::Proto::DNS::UpstreamRule.spell_check_resolver(resolver)).present?
289
          message << " Did you mean #{suggestions.first}?"
290
        end
291

292
        raise ::ArgumentError.new(message)
293
      end
294
    end
295

296
    comm_obj = nil
297

298
    unless comm.nil?
299
      raise ::ArgumentError.new("Not a valid session: #{comm}") unless comm =~ /\A-?[0-9]+\Z/
300

301
      comm_obj = driver.framework.sessions.get(comm.to_i)
302
      raise ::ArgumentError.new("Session does not exist: #{comm}") unless comm_obj
303
      raise ::ArgumentError.new("Socket Comm (Session #{comm}) does not implement Rex::Socket::Comm") unless comm_obj.is_a? ::Rex::Socket::Comm
304

305
      if resolvers.any? { |resolver| SPECIAL_RESOLVERS.include?(resolver.downcase) }
306
        print_warning("The session argument will be ignored for the system resolver")
307
      end
308
    end
309

310
    rules.each_with_index do |rule, offset|
311
      print_warning("DNS rule #{rule} does not contain wildcards, it will not match subdomains") unless rule.include?('*')
312
      driver.framework.dns_resolver.add_upstream_rule(
313
        resolvers,
314
        comm: comm_obj,
315
        wildcard: rule,
316
        index: (index == -1 ? -1 : offset + index)
317
      )
318
    end
319

320
    print_good("#{rules.length} DNS #{rules.length > 1 ? 'entries' : 'entry'} added")
321
  end
322

323
  def add_dns_help
324
    print_line "USAGE:"
325
    print_line "  #{ADD_USAGE}"
326
    print_line @@add_opts.usage
327
    print_line "RESOLVERS:"
328
    print_line "  ipv4 / ipv6 address - The IP address of an upstream DNS server to resolve from"
329
    print_line "  #{Rex::Proto::DNS::UpstreamResolver::Type::BLACK_HOLE.to_s.ljust(19)} - Drop all queries"
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    print_line "  #{Rex::Proto::DNS::UpstreamResolver::Type::STATIC.to_s.ljust(19)    } - Reply with statically configured addresses (only for A/AAAA records)"
331
    print_line "  #{Rex::Proto::DNS::UpstreamResolver::Type::SYSTEM.to_s.ljust(19)    } - Use the host operating systems DNS resolution functionality (only for A/AAAA records)"
332
    print_line
333
    print_line "EXAMPLES:"
334
    print_line "  Set the DNS server(s) to be used for *.metasploit.com to 192.168.1.10"
335
    print_line "    dns add --rule *.metasploit.com 192.168.1.10"
336
    print_line
337
    print_line "  Add multiple entries at once"
338
    print_line "    dns add --rule *.metasploit.com --rule *.google.com 192.168.1.10 192.168.1.11"
339
    print_line
340
    print_line "  Set the DNS server(s) to be used for *.metasploit.com to 192.168.1.10, but specifically to go through session 2"
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    print_line "    dns add --session 2 --rule *.metasploit.com 192.168.1.10"
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  end
343

344
  def add_static_dns(*args)
345
    if args.length < 2
346
      raise ::ArgumentError.new('A hostname and IP address must be provided')
347
    end
348

349
    hostname = args.shift
350
    if !Rex::Proto::DNS::StaticHostnames.is_valid_hostname?(hostname)
351
      raise ::ArgumentError.new("Invalid hostname: #{hostname}")
352
    end
353

354
    ip_addresses = args
355
    if (ip_address = ip_addresses.find { |a| !Rex::Socket.is_ip_addr?(a) })
356
      raise ::ArgumentError.new("Invalid IP address: #{ip_address}")
357
    end
358

359
    ip_addresses.each do |ip_address|
360
      resolver.static_hostnames.add(hostname, ip_address)
361
      print_status("Added static hostname mapping #{hostname} to #{ip_address}")
362
    end
363
  end
364

365
  def add_static_dns_help
366
    print_line "USAGE:"
367
    print_line "  #{ADD_STATIC_USAGE}"
368
    print_line
369
    print_line "EXAMPLES:"
370
    print_line "  Define a static entry mapping localhost6 to ::1"
371
    print_line "    dns add-static localhost6 ::1"
372
  end
373

374
  #
375
  # Query a hostname using the configuration. This is useful for debugging and
376
  # inspecting the active settings.
377
  #
378
  def resolve_dns(*args)
379
    names = []
380
    query_type = Dnsruby::Types::A
381

382
    @@resolve_opts.parse(args) do |opt, idx, val|
383
      unless names.empty? || opt.nil?
384
        raise ::ArgumentError.new("Invalid command near #{opt}")
385
      end
386
      case opt
387
      when '-f'
388
        case val.downcase
389
        when 'ipv4'
390
          query_type = Dnsruby::Types::A
391
        when'ipv6'
392
          query_type = Dnsruby::Types::AAAA
393
        else
394
          raise ::ArgumentError.new("Invalid family: #{val}")
395
        end
396
      when nil
397
        names << val
398
      else
399
        raise ::ArgumentError.new("Unknown flag: #{opt}")
400
      end
401
    end
402

403
    if names.length < 1
404
      raise ::ArgumentError.new('You must specify at least one hostname to resolve')
405
    end
406

407
    tbl = Table.new(
408
      Table::Style::Default,
409
      'Header'    => 'Host resolutions',
410
      'Prefix'    => "\n",
411
      'Postfix'   => "\n",
412
      'Columns'   => ['Hostname', 'IP Address', 'Rule #', 'Rule', 'Resolver', 'Comm channel'],
413
      'ColProps'  => { 'Hostname' => { 'Strip' => false } },
414
      'SortIndex' => -1,
415
      'WordWrap'  => false
416
    )
417
    names.each do |name|
418
      upstream_rule = resolver.upstream_rules.find { |ur| ur.matches_name?(name) }
419
      if upstream_rule.nil?
420
        tbl << [name, '[Failed To Resolve]', '', '', '', '']
421
        next
422
      end
423

424
      upstream_rule_idx = resolver.upstream_rules.index(upstream_rule) + 1
425

426
      begin
427
        result = resolver.query(name, query_type)
428
      rescue NoResponseError
429
        tbl = append_resolver_cells!(tbl, upstream_rule, prefix: [name, '[Failed To Resolve]'], index: upstream_rule_idx)
430
      else
431
        if result.answer.empty?
432
          tbl = append_resolver_cells!(tbl, upstream_rule, prefix: [name, '[Failed To Resolve]'], index: upstream_rule_idx)
433
        else
434
          result.answer.select do |answer|
435
            answer.type == query_type
436
          end.map(&:address).map(&:to_s).each do |address|
437
            tbl = append_resolver_cells!(tbl, upstream_rule, prefix: [name, address], index: upstream_rule_idx)
438
          end
439
        end
440
      end
441
    end
442
    print(tbl.to_s)
443
  end
444

445
  def resolve_dns_help
446
    print_line "USAGE:"
447
    print_line "  #{RESOLVE_USAGE}"
448
    print_line @@resolve_opts.usage
449
    print_line "EXAMPLES:"
450
    print_line "  Resolve a hostname to an IPv6 address using the current configuration"
451
    print_line "    dns resolve -f IPv6 www.metasploit.com"
452
    print_line
453
  end
454

455
  #
456
  # Remove all matching user-configured DNS entries
457
  #
458
  def remove_dns(*args)
459
    remove_ids = []
460
    @@remove_opts.parse(args) do |opt, idx, val|
461
      case opt
462
      when '-i', '--index'
463
        raise ::ArgumentError.new("Not a valid index: #{val}") unless val.to_i > 0
464

465
        remove_ids << val.to_i - 1
466
      end
467
    end
468

469
    if remove_ids.empty?
470
      raise ::ArgumentError.new('At least one index to remove must be provided')
471
    end
472

473
    removed = resolver.remove_ids(remove_ids)
474
    print_warning('Some entries were not removed') unless removed.length == remove_ids.length
475
    if removed.length > 0
476
      print_good("#{removed.length} DNS #{removed.length > 1 ? 'entries' : 'entry'} removed")
477
      print_dns_set('Deleted entries', removed, ids: [nil] * removed.length)
478
    end
479
  end
480

481
  def remove_dns_help
482
    print_line "USAGE:"
483
    print_line "  #{REMOVE_USAGE}"
484
    print_line(@@remove_opts.usage)
485
    print_line "EXAMPLES:"
486
    print_line "  Delete the DNS resolution rule #3"
487
    print_line "    dns remove -i 3"
488
    print_line
489
    print_line "  Delete multiple rules in one command"
490
    print_line "    dns remove -i 3 -i 4 -i 5"
491
    print_line
492
  end
493

494
  def remove_static_dns(*args)
495
    if args.length < 1
496
      raise ::ArgumentError.new('A hostname must be provided')
497
    end
498

499
    hostname = args.shift
500
    if !Rex::Proto::DNS::StaticHostnames.is_valid_hostname?(hostname)
501
      raise ::ArgumentError.new("Invalid hostname: #{hostname}")
502
    end
503

504
    ip_addresses = args
505
    if ip_addresses.empty?
506
      ip_addresses = resolver.static_hostnames.get(hostname, Dnsruby::Types::A) + resolver.static_hostnames.get(hostname, Dnsruby::Types::AAAA)
507
      if ip_addresses.empty?
508
        print_status("There are no definitions for hostname: #{hostname}")
509
      end
510
    elsif (ip_address = ip_addresses.find { |ip| !Rex::Socket.is_ip_addr?(ip) })
511
      raise ::ArgumentError.new("Invalid IP address: #{ip_address}")
512
    end
513

514
    ip_addresses.each do |ip_address|
515
      resolver.static_hostnames.delete(hostname, ip_address)
516
      print_status("Removed static hostname mapping #{hostname} to #{ip_address}")
517
    end
518
  end
519

520
  def remove_static_dns_help
521
    print_line "USAGE:"
522
    print_line "  #{REMOVE_STATIC_USAGE}"
523
    print_line
524
    print_line "EXAMPLES:"
525
    print_line "  Remove all IPv4 and IPv6 addresses for 'localhost'"
526
    print_line "    dns remove-static localhost"
527
    print_line
528
  end
529

530
  def reset_config_dns(*args)
531
    add_system_resolver = false
532
    should_confirm = true
533
    @@reset_config_opts.parse(args) do |opt, idx, val|
534
      case opt
535
      when '--system'
536
        add_system_resolver = true
537
      when '-y', '--yes'
538
        should_confirm = false
539
      end
540
    end
541

542
    if should_confirm
543
      print("Are you sure you want to reset the DNS configuration? [y/N]: ")
544
      response = gets.downcase.chomp
545
      return unless response =~ /^y/i
546
    end
547

548
    resolver.reinit
549
    print_status('The DNS configuration has been reset')
550

551
    if add_system_resolver
552
      # if the user requested that we add the system resolver
553
      system_resolver = Rex::Proto::DNS::UpstreamResolver.create_system
554
      # first find the default, catch-all rule
555
      default_rule = resolver.upstream_rules.find { |ur| ur.matches_all? }
556
      if default_rule.nil?
557
        resolver.add_upstream_rule([ system_resolver ])
558
      else
559
        # if the first resolver is for static hostnames, insert after that one
560
        if default_rule.resolvers.first&.type == Rex::Proto::DNS::UpstreamResolver::Type::STATIC
561
          index = 1
562
        else
563
          index = 0
564
        end
565
        default_rule.resolvers.insert(index, system_resolver)
566
      end
567
    end
568

569
    print_dns
570

571
    if ENV['PROXYCHAINS_CONF_FILE'] && !add_system_resolver
572
      print_warning('Detected proxychains but the system resolver was not added')
573
    end
574
  end
575

576
  def reset_config_dns_help
577
    print_line "USAGE:"
578
    print_line "  #{RESET_CONFIG_USAGE}"
579
    print_line @@reset_config_opts.usage
580
    print_line "EXAMPLES:"
581
    print_line "  Reset the configuration without prompting to confirm"
582
    print_line "    dns reset-config --yes"
583
    print_line
584
  end
585

586
  #
587
  # Delete all cached DNS answers
588
  #
589
  def flush_cache_dns
590
    resolver.cache.flush
591
    print_good('DNS cache flushed')
592
  end
593

594
  #
595
  # Delete all user-configured DNS settings
596
  #
597
  def flush_entries_dns
598
    resolver.flush
599
    print_good('DNS entries flushed')
600
  end
601

602
  def flush_static_dns
603
    resolver.static_hostnames.flush
604
    print_good('DNS static hostnames flushed')
605
  end
606

607
  #
608
  # Display the user-configured DNS settings
609
  #
610
  def print_dns
611
    default_domain = 'N/A'
612
    if resolver.defname? && resolver.domain.present?
613
      default_domain = resolver.domain
614
    end
615
    print_line("Default search domain: #{default_domain}")
616

617
    searchlist = resolver.searchlist
618
    case searchlist.length
619
    when 0
620
      print_line('Default search list:   N/A')
621
    when 1
622
      print_line("Default search list:   #{searchlist.first}")
623
    else
624
      print_line('Default search list:')
625
      searchlist.each do |entry|
626
        print_line("  * #{entry}")
627
      end
628
    end
629
    print_line("Current cache size:    #{resolver.cache.records.length}")
630

631
    upstream_rules = resolver.upstream_rules
632
    print_dns_set('Resolver rule entries', upstream_rules, ids: (1..upstream_rules.length).to_a)
633
    if upstream_rules.empty?
634
      print_line
635
      print_error('No DNS nameserver entries configured')
636
    end
637

638
    tbl = Table.new(
639
      Table::Style::Default,
640
      'Header'    => 'Static hostnames',
641
      'Prefix'    => "\n",
642
      'Postfix'   => "\n",
643
      'Columns'   => ['Hostname', 'IPv4 Address', 'IPv6 Address'],
644
      'ColProps'  => { 'Hostname' => { 'Strip' => false } },
645
      'SortIndex' => -1,
646
      'WordWrap'  => false
647
    )
648
    resolver.static_hostnames.sort_by { |hostname, _| hostname }.each do |hostname, addresses|
649
      ipv4_addresses = addresses.fetch(Dnsruby::Types::A, []).sort_by(&:to_i)
650
      ipv6_addresses = addresses.fetch(Dnsruby::Types::AAAA, []).sort_by(&:to_i)
651
      if (ipv4_addresses.length <= 1 && ipv6_addresses.length <= 1) && ((ipv4_addresses + ipv6_addresses).length > 0)
652
        tbl << [hostname, ipv4_addresses.first, ipv6_addresses.first]
653
      else
654
        tbl << [hostname, '', '']
655
        0.upto([ipv4_addresses.length, ipv6_addresses.length].max - 1) do |idx|
656
          tbl << [TABLE_INDENT, ipv4_addresses[idx], ipv6_addresses[idx]]
657
        end
658
      end
659
    end
660
    print_line(tbl.to_s)
661
    if resolver.static_hostnames.empty?
662
      print_line('No static hostname entries are configured')
663
    end
664
  end
665

666
  private
667

668
  SPECIAL_RESOLVERS = [
669
    Rex::Proto::DNS::UpstreamResolver::Type::BLACK_HOLE.to_s.downcase,
670
    Rex::Proto::DNS::UpstreamResolver::Type::SYSTEM.to_s.downcase
671
  ].freeze
672

673
  TABLE_INDENT = "  \\_ ".freeze
674

675
  #
676
  # Get user-friendly text for displaying the session that this entry would go through
677
  #
678
  def prettify_comm(comm, upstream_resolver)
679
    if !Rex::Socket.is_ip_addr?(upstream_resolver.destination)
680
      'N/A'
681
    elsif comm.nil?
682
      channel = Rex::Socket::SwitchBoard.best_comm(upstream_resolver.destination)
683
      if channel.nil?
684
        nil
685
      else
686
        "Session #{channel.sid} (route)"
687
      end
688
    else
689
      if comm.alive?
690
        "Session #{comm.sid}"
691
      else
692
        "Closed session (#{comm.sid})"
693
      end
694
    end
695
  end
696

697
  def print_dns_set(heading, result_set, ids: [])
698
    return if result_set.length == 0
699
    columns = ['#', 'Rule', 'Resolver', 'Comm channel']
700
    col_props = { 'Rule' => { 'Strip' => false } }
701

702
    tbl = Table.new(
703
      Table::Style::Default,
704
      'Header'    => heading,
705
      'Prefix'    => "\n",
706
      'Postfix'   => "\n",
707
      'Columns'   => columns,
708
      'ColProps' => col_props,
709
      'SortIndex' => -1,
710
      'WordWrap'  => false
711
    )
712
    result_set.each_with_index do |entry, index|
713
      tbl = append_resolver_cells!(tbl, entry, index: ids[index])
714
    end
715

716
    print(tbl.to_s) if tbl.rows.length > 0
717
  end
718

719
  def append_resolver_cells!(tbl, entry, prefix: [], suffix: [], index: nil)
720
    alignment_prefix = prefix.empty? ? [] : (['.'] * prefix.length)
721

722
    if entry.resolvers.length == 1
723
      tbl << prefix + [index.to_s, entry.wildcard, entry.resolvers.first, prettify_comm(entry.comm, entry.resolvers.first)] + suffix
724
    elsif entry.resolvers.length > 1
725
      tbl << prefix + [index.to_s, entry.wildcard, '', ''] + suffix
726
      entry.resolvers.each do |resolver|
727
        tbl << alignment_prefix + ['.', TABLE_INDENT, resolver, prettify_comm(entry.comm, resolver)] + ([''] * suffix.length)
728
      end
729
    end
730
    tbl
731
  end
732

733
  def resolver
734
    self.driver.framework.dns_resolver
735
  end
736
end
737

738
end
739
end
740
end
741
end
742

743