open_datagram_socket / open_udp_socket中的EventMachine RuntimeError没有数据报套接字

Question

当我在端口open_datagram_socket上尝试1900时出现以下错误：

/Users/timbaas/.rvm/gems/ruby-1.9.3-p194/gems/eventmachine-1.0.0/lib/eventmachine.rb:859:in `open_udp_socket': no datagram socket (RuntimeError)
from /Users/timbaas/.rvm/gems/ruby-1.9.3-p194/gems/eventmachine-1.0.0/lib/eventmachine.rb:859:in `open_datagram_socket'
from /Users/timbaas/Applications/ruby/upnp/ssdp.rb:36:in `block in initialize'
from /Users/timbaas/.rvm/gems/ruby-1.9.3-p194/gems/eventmachine-1.0.0/lib/eventmachine.rb:187:in `call'
from /Users/timbaas/.rvm/gems/ruby-1.9.3-p194/gems/eventmachine-1.0.0/lib/eventmachine.rb:187:in `run_machine'
from /Users/timbaas/.rvm/gems/ruby-1.9.3-p194/gems/eventmachine-1.0.0/lib/eventmachine.rb:187:in `run'
from /Users/timbaas/Applications/ruby/upnp/ssdp.rb:35:in `initialize'
from upnp.rb:4:in `new'
from upnp.rb:4:in `<main>'

我在Ruby 1.9.3上使用以下代码：

module SSDP

  IP = "239.255.255.250"
  PORT = 1900

  class Server < EM::Connection
    def receive_data(data)
      p "d" + data
    end
  end

  class Socket
    attr_accessor :socket

    def initialize
      EventMachine::run do
        @socket = EM::open_datagram_socket SSDP::IP, SSDP::PORT, SSDP::Server
        p "Started EchoServer on #{SSDP::IP}:#{SSDP::PORT}..."
      end
    end
  end
end

Socket.new

当我使用端口1901时，它可以工作..

由于