class Gem::Resolv::DNS::Requester::UnconnectedUDP

def close
  @mutex.synchronize {
    if @initialized
      super
      @senders.each_key {|service, id|
        DNS.free_request_id(service[0], service[1], id)
      }
      @initialized = false
    end
  }
end

def initialize(*nameserver_port)
  super()
  @nameserver_port = nameserver_port
  @initialized = false
  @mutex = Thread::Mutex.new
end

def lazy_initialize
  @mutex.synchronize {
    next if @initialized
    @initialized = true
    @socks_hash = {}
    @socks = []
    @nameserver_port.each {|host, port|
      if host.index(':')
        bind_host = "::"
        af = Socket::AF_INET6
      else
        bind_host = "0.0.0.0"
        af = Socket::AF_INET
      end
      next if @socks_hash[bind_host]
      begin
        sock = UDPSocket.new(af)
      rescue Errno::EAFNOSUPPORT, Errno::EPROTONOSUPPORT
        next # The kernel doesn't support the address family.
      end
      @socks << sock
      @socks_hash[bind_host] = sock
      sock.do_not_reverse_lookup = true
      DNS.bind_random_port(sock, bind_host)
    }
  }
  self
end

def recv_reply(readable_socks)
  lazy_initialize
  reply, from = readable_socks[0].recvfrom(UDPSize)
  return reply, [from[3],from[1]]
end

def sender(msg, data, host, port=Port)
  host = Addrinfo.ip(host).ip_address
  lazy_initialize
  sock = @socks_hash[host.index(':') ? "::" : "0.0.0.0"]
  return nil if !sock
  service = [host, port]
  id = DNS.allocate_request_id(host, port)
  request = msg.encode
  request[0,2] = [id].pack('n')
  return @senders[[service, id]] =
    Sender.new(request, data, sock, host, port)
end