La ricerca del router tramite l'invio di pacchetti broadcast tramite UPnP non funziona

Question

Sto cercando di implementare una semplice libreria in grado di rilevare il router tramite il protocollo UPnP se l'applicazione è in esecuzione in un ambiente NAT. Ho provato due modi, multi-cast e datagramma, per inviare il pacchetto di scoperta al router e provare ad ascoltare la porta 1901 per la risposta dal router. Tuttavia, ho alcuni problemi con i codici. Ho provato i seguenti tre tipi di modi, e solo il terzo può ricevere correttamente la risposta dal router. Non ho idea del perché non funzioni sul primo e sul secondo modo.

Il primo: invia il pacchetto multi-cast e ascolta la porta 1901 per la risposta.

Codici:

public void discovery() throws IOException { 
    // SSDP port 
    final int SSDP_PORT = 1900; 
    final int SSDP_SEARCH_PORT = 1901; 
    // Broadcast address for finding routers. 
    final String SSDP_IP = "239.255.255.250"; 
    // Time out of the connection. 
    int TIMEOUT = 5000; 
    // Localhost address. 
    InetAddress localhost = InetAddress.getLocalHost(); 

    // Send from localhost:1901 
    InetSocketAddress srcAddress = new InetSocketAddress(localhost, SSDP_SEARCH_PORT); 
    // Send to 239.255.255.250:1900 
    InetSocketAddress dstAddress = new InetSocketAddress(InetAddress.getByName(SSDP_IP), SSDP_PORT); 

    // ----------------------------------------- // 
    //  Construct the request packet.  // 
    // ----------------------------------------- // 
    StringBuffer discoveryMessage = new StringBuffer(); 
    discoveryMessage.append("M-SEARCH * HTTP/1.1\r\n"); 
    discoveryMessage.append("HOST: " + SSDP_IP + ":" + SSDP_PORT + "\r\n"); 
    discoveryMessage.append("ST: urn:schemas-upnp-org:device:InternetGatewayDevice:1\r\n"); 
    // ST: urn:schemas-upnp-org:service:WANIPConnection:1\r\n 
    discoveryMessage.append("MAN: \"ssdp:discover\"\r\n"); 
    discoveryMessage.append("MX: 2\r\n"); 
    discoveryMessage.append("\r\n"); 
    // System.out.println("Request: " + discoveryMessage.toString() + "\n"); 
    byte[] discoveryMessageBytes = discoveryMessage.toString().getBytes(); 
    DatagramPacket discoveryPacket = new DatagramPacket(discoveryMessageBytes, discoveryMessageBytes.length, dstAddress); 

    // ----------------------------------- // 
    //  Send multi-cast packet.  // 
    // ----------------------------------- // 
    MulticastSocket multicast = null; 
    try { 
     multicast = new MulticastSocket(null); 
     multicast.bind(srcAddress); 
     multicast.setTimeToLive(4); 
     System.out.println("Send multicast request."); 
     // ----- Sending multi-cast packet ----- // 
     multicast.send(discoveryPacket); 
    } finally { 
     System.out.println("Multicast ends. Close connection."); 
     multicast.disconnect(); 
     multicast.close(); 
    } 

    // -------------------------------------------------- // 
    //  Listening to response from the router.  // 
    // -------------------------------------------------- // 
    DatagramSocket wildSocket = null; 
    DatagramPacket receivePacket = null; 
    try { 
     wildSocket = new DatagramSocket(SSDP_SEARCH_PORT); 
     wildSocket.setSoTimeout(TIMEOUT); 

     while (true) { 
      try { 
       System.out.println("Receive ssdp."); 
       receivePacket = new DatagramPacket(new byte[1536], 1536); 
       wildSocket.receive(receivePacket); 
       String message = new String(receivePacket.getData()); 
       System.out.println("Recieved messages:"); 
       System.out.println(message); 
      } catch (SocketTimeoutException e) { 
       System.err.print("Time out."); 
       break; 
      } 
     } 
    } finally { 
     if (wildSocket != null) { 
      wildSocket.disconnect(); 
      wildSocket.close(); 
     } 
    } 
} 

Risultato: Il router fa pacchetto di risposta (sniffered da Wireshark, come la schermata seguente), ma il codice non recieve nulla. code 1 http://img705.imageshack.us/img705/6531/ssdp1.png

risultato Codice:

Send multicast request. 
Multicast ends. Close connection. 
Receive ssdp. 
Time out. 

Il secondo: inviare datagram di pacchetti, e in ascolto sulla porta 1901 per la risposta.

Codici:

public void discovery() throws IOException { 
    // Ignore this part of the codes since they are the same as the first one. 
    .............. 

    // -------------------------------------------------- // 
    //  Listening to response from the router.  // 
    // -------------------------------------------------- // 
    DatagramSocket wildSocket = null; 
    DatagramPacket receivePacket = null; 
    try { 
     wildSocket = new DatagramSocket(SSDP_SEARCH_PORT); 
     wildSocket.setSoTimeout(TIMEOUT); 
     // ----- Sending datagram packet ----- // 
     System.out.println("Send datagram packet."); 
     wildSocket.send(discoveryPacket); 

     while (true) { 
      try { 
       System.out.println("Receive ssdp."); 
       receivePacket = new DatagramPacket(new byte[1536], 1536); 
       wildSocket.receive(receivePacket); 
       String message = new String(receivePacket.getData()); 
       System.out.println("Recieved messages:"); 
       System.out.println(message); 
      } catch (SocketTimeoutException e) { 
       System.err.print("Time out."); 
       break; 
      } 
     } 
    } finally { 
     if (wildSocket != null) { 
      wildSocket.disconnect(); 
      wildSocket.close(); 
     } 
    } 
} 

Risultato: Wireshark non ottiene nulla. Nessun pacchetto viene sniffered sulla porta 1900 e il 1901.

risultato Codice:

Send datagram packet. 
Receive ssdp. 
Time out. 

Il terzo: inviare multi-Cast e datagramma pacchetti, e in ascolto sulla porta 1901 per la risposta.

Codici:

public void discovery() throws IOException { 
    // Ignore this part of the codes since they are the same as the first one. 
    .............. 

    // ----------------------------------- // 
    //  Send multi-cast packet.  // 
    // ----------------------------------- // 
    MulticastSocket multicast = null; 
    try { 
     multicast = new MulticastSocket(null); 
     multicast.bind(srcAddress); 
     multicast.setTimeToLive(4); 
     System.out.println("Send multicast request."); 
     // ----- Sending multi-cast packet ----- // 
     multicast.send(discoveryPacket); 
    } finally { 
     System.out.println("Multicast ends. Close connection."); 
     multicast.disconnect(); 
     multicast.close(); 
    } 

    // -------------------------------------------------- // 
    //  Listening to response from the router.  // 
    // -------------------------------------------------- // 
    DatagramSocket wildSocket = null; 
    DatagramPacket receivePacket = null; 
    try { 
     wildSocket = new DatagramSocket(SSDP_SEARCH_PORT); 
     wildSocket.setSoTimeout(TIMEOUT); 
     // ----- Sending datagram packet ----- // 
     System.out.println("Send datagram packet."); 
     wildSocket.send(discoveryPacket); 

     while (true) { 
      try { 
       System.out.println("Receive ssdp."); 
       receivePacket = new DatagramPacket(new byte[1536], 1536); 
       wildSocket.receive(receivePacket); 
       String message = new String(receivePacket.getData()); 
       System.out.println("Recieved messages:"); 
       System.out.println(message); 
      } catch (SocketTimeoutException e) { 
       System.err.print("Time out."); 
       break; 
      } 
     } 
    } finally { 
     if (wildSocket != null) { 
      wildSocket.disconnect(); 
      wildSocket.close(); 
     } 
    } 
} 

risultati: inviare due pacchetti di broadcast successo, e ottenere due risposte da router. code 1 http://img707.imageshack.us/img707/1607/ssdp3.png

risultato Codice:

Send multicast request. 
Multicast ends. Close connection. 
Send datagram packet. 
Receive ssdp. 
Recieved messages: 
HTTP/1.1 200 OK 
Cache-Control: max-age=300 
Date: Wed, 06 Mar 2013 05:15:43 GMT 
Ext: 
Location: http://192.168.1.1:1780/InternetGatewayDevice.xml 
Server: POSIX UPnP/1.0 DD-WRT Linux/V24 
ST: urn:schemas-upnp-org:device:InternetGatewayDevice:1 
USN: uuid:C42C1F3F-6E63-7FFC-F982-035B355D6E76::urn:schemas-upnp-org:device:InternetGatewayDevice:1 

Receive ssdp. 
Recieved messages: 
HTTP/1.1 200 OK 
Cache-Control: max-age=300 
Date: Wed, 06 Mar 2013 05:15:43 GMT 
Ext: 
Location: http://192.168.1.1:1780/InternetGatewayDevice.xml 
Server: POSIX UPnP/1.0 DD-WRT Linux/V24 
ST: urn:schemas-upnp-org:device:InternetGatewayDevice:1 
USN: uuid:C42C1F3F-6E63-7FFC-F982-035B355D6E76::urn:schemas-upnp-org:device:InternetGatewayDevice:1 

Receive ssdp. 
Time out. 

C'è qualche idea del perché il primo e il secondo modo è riuscito a chiedere al router tramite protocollo UPnP? E perché il secondo sembra non inviare nulla?

Grazie mille!

Answer 1

Suppongo che potrebbe trattarsi di un problema relativo al firmware del router OS +. Assicurati che il tuo firewall sia spento.

Prima Methot: Questo metodo non funziona per niente sul mio computer (OS X):

Send multicast request. 
Exception in thread "main" java.io.IOException: Can't assign requested address 
Multicast ends. Close connection. 
    at java.net.PlainDatagramSocketImpl.send(Native Method) 
    at java.net.DatagramSocket.send(DatagramSocket.java:676) 
    at Test.discovery(Test.java:55) 
    at Test.main(Test.java:93) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:601) 
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120) 

Tuttavia, dopo che ho cambiato:

InetSocketAddress srcAddress = new InetSocketAddress(localhost, SSDP_SEARCH_PORT); 

a

InetSocketAddress srcAddress = new InetSocketAddress(SSDP_SEARCH_PORT); 

Funziona perfettamente:

Send multicast request. 
Multicast ends. Close connection. 
Receive ssdp. 
Recieved messages: 
HTTP/1.1 200 OK 
Cache-Control: max-age=60 
Date: Sun, 04 Jan 1970 21:55:18 GMT 
Ext: 
Location: http://192.168.0.2:1780/InternetGatewayDevice.xml 
Server: POSIX UPnP/1.0 linux/5.20.61.0 
ST: urn:schemas-upnp-org:device:InternetGatewayDevice:1 
USN: uuid:C04E066F-F351-72B6-CCCF-E98237DCB05C::urn:schemas-upnp-org:device:InternetGatewayDevice:1 


Receive ssdp. 
Time out. 

Secondo metodo: Works.

Terzo metodo: Opere.

(troppo lungo per il commento)

[modifica]

Nel caso in cui il vostro obiettivo è quello di produrre software stabile, Consiglierei di attenersi a modo convenzionale: https://stackoverflow.com/a/4405143