--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/src/main/java/net/sourceforge/jsocks/Socks5DatagramSocket.java	Thu Dec 03 11:23:55 2015 -0800
@@ -0,0 +1,487 @@
+package net.sourceforge.jsocks;
+import java.net.*;
+import java.io.*;
+
+/**
+  Datagram socket to interract through the firewall.<BR>
+  Can be used same way as the normal DatagramSocket. One should
+  be carefull though with the datagram sizes used, as additional data
+  is present in both incomming and outgoing datagrams.
+   <p>
+   SOCKS5 protocol allows to send host address as either:
+   <ul>
+    <li> IPV4, normal 4 byte address. (10 bytes header size)
+    <li> IPV6, version 6 ip address (not supported by Java as for now).
+         22 bytes header size.
+    <li> Host name,(7+length of the host name bytes header size).
+   </ul>
+  As with other Socks equivalents, direct addresses are handled
+  transparently, that is data will be send directly when required 
+  by the proxy settings.
+  <p>
+  <b>NOTE:</b><br>
+  Unlike other SOCKS Sockets, it <b>does not</b> support proxy chaining,
+  and will throw an exception if proxy has a chain proxy attached. The
+  reason for that is not my laziness, but rather the restrictions of
+  the SOCKSv5 protocol. Basicaly SOCKSv5 proxy server, needs to know from
+  which host:port datagrams will be send for association, and returns address
+  to which datagrams should be send by the client, but it does not
+  inform client from which host:port it is going to send datagrams, in fact
+  there is even no guarantee they will be send at all and from the same address
+  each time.
+ 
+ */
+public class Socks5DatagramSocket extends DatagramSocket{
+
+   InetAddress relayIP;
+   int relayPort;
+   Socks5Proxy proxy;
+   private boolean server_mode = false;
+   UDPEncapsulation encapsulation;
+
+
+   /**
+      Construct Datagram socket for communication over SOCKS5 proxy
+      server. This constructor uses default proxy, the one set with
+      CProxy.setDefaultProxy() method. If default proxy is not set or
+      it is set to version4 proxy, which does not support datagram
+      forwarding, throws SocksException.
+
+    */
+   public Socks5DatagramSocket() throws SocksException,
+                                        IOException{
+      this(CProxy.defaultProxy,0,null);
+   }
+   /**
+      Construct Datagram socket for communication over SOCKS5 proxy
+      server. And binds it to the specified local port.
+      This constructor uses default proxy, the one set with
+      CProxy.setDefaultProxy() method. If default proxy is not set or
+      it is set to version4 proxy, which does not support datagram
+      forwarding, throws SocksException.
+    */
+   public Socks5DatagramSocket(int port) throws SocksException,
+                                                IOException{
+      this(CProxy.defaultProxy,port,null);
+   }
+   /**
+      Construct Datagram socket for communication over SOCKS5 proxy
+      server. And binds it to the specified local port and address.
+      This constructor uses default proxy, the one set with
+      CProxy.setDefaultProxy() method. If default proxy is not set or
+      it is set to version4 proxy, which does not support datagram
+      forwarding, throws SocksException.
+    */
+   public Socks5DatagramSocket(int port,InetAddress ip) throws SocksException,
+                                        IOException{
+      this(CProxy.defaultProxy,port,ip);
+   }
+
+   /**
+     Constructs datagram socket for communication over specified proxy.
+     And binds it to the given local address and port. Address of null 
+     and port of 0, signify any availabale port/address.
+     Might throw SocksException, if:
+     <ol>
+      <li> Given version of proxy does not support UDP_ASSOCIATE.
+      <li> CProxy can't be reached.
+      <li> Authorization fails.
+      <li> CProxy does not want to perform udp forwarding, for any reason.
+     </ol>
+     Might throw IOException if binding dtagram socket to given address/port
+     fails.
+     See java.net.DatagramSocket for more details.
+    */
+   public Socks5DatagramSocket(CProxy p,int port,InetAddress ip)
+                                        throws SocksException,
+                                               IOException{
+      super(port,ip);
+      if(p == null) throw new SocksException(CProxy.SOCKS_NO_PROXY);
+      if(!(p instanceof Socks5Proxy)) 
+         throw new SocksException(-1,"Datagram Socket needs Proxy version 5");
+
+      if(p.chainProxy != null)
+           throw new SocksException(CProxy.SOCKS_JUST_ERROR,
+               "Datagram Sockets do not support proxy chaining.");
+
+      proxy =(Socks5Proxy) p.copy();
+
+      ProxyMessage msg = proxy.udpAssociate(super.getLocalAddress(),
+                                            super.getLocalPort());
+      relayIP = msg.ip;
+      if(relayIP.getHostAddress().equals("0.0.0.0")) relayIP = proxy.proxyIP;
+      relayPort = msg.port;
+
+      encapsulation = proxy.udp_encapsulation;
+
+      //debug("Datagram Socket:"+getLocalAddress()+":"+getLocalPort()+"\n");
+      //debug("Socks5Datagram: "+relayIP+":"+relayPort+"\n");
+   }
+
+   /**
+     Used by UDPRelayServer.
+    */
+   Socks5DatagramSocket(boolean server_mode,UDPEncapsulation encapsulation,
+                        InetAddress relayIP,int relayPort)
+                        throws IOException{
+      super();
+      this.server_mode = server_mode;
+      this.relayIP = relayIP;
+      this.relayPort = relayPort;
+      this.encapsulation = encapsulation;
+      this.proxy = null;
+   }
+
+   /**
+     Sends the Datagram either through the proxy or directly depending
+     on current proxy settings and destination address. <BR>
+
+     <B> NOTE: </B> DatagramPacket size should be at least 10 bytes less
+                    than the systems limit.
+
+     <P>
+     See documentation on java.net.DatagramSocket
+     for full details on how to use this method. 
+     @param dp Datagram to send.
+     @throws IOException If error happens with I/O.
+    */
+   public void send(DatagramPacket dp) throws IOException{
+     //If the host should be accessed directly, send it as is.
+     if(!server_mode && proxy.isDirect(dp.getAddress())){
+        super.send(dp);
+        //debug("Sending directly:");
+        return;
+     }
+
+     byte[] head = formHeader(dp.getAddress(),dp.getPort());
+     byte[] buf = new byte[head.length + dp.getLength()];
+     byte[] data = dp.getData();
+     //Merge head and data
+     System.arraycopy(head,0,buf,0,head.length);
+     //System.arraycopy(data,dp.getOffset(),buf,head.length,dp.getLength());
+     System.arraycopy(data,0,buf,head.length,dp.getLength());
+
+     if(encapsulation != null)
+        buf = encapsulation.udpEncapsulate(buf,true);
+
+     super.send(new DatagramPacket(buf,buf.length,relayIP,relayPort));
+   }
+   /**
+     This method allows to send datagram packets with address type DOMAINNAME.
+     SOCKS5 allows to specify host as names rather than ip addresses.Using
+     this method one can send udp datagrams through the proxy, without having
+     to know the ip address of the destination host.
+     <p> 
+     If proxy specified for that socket has an option resolveAddrLocally set
+     to true host will be resolved, and the datagram will be send with address
+     type IPV4, if resolve fails, UnknownHostException is thrown.
+     @param dp Datagram to send, it should contain valid port and data
+     @param host Host name to which datagram should be send.
+     @throws IOException If error happens with I/O, or the host can't be 
+     resolved when proxy settings say that hosts should be resolved locally.
+     @see Socks5Proxy#resolveAddrLocally(boolean)
+    */
+   public void send(DatagramPacket dp, String host) throws IOException{
+     if(proxy.isDirect(host)){
+        dp.setAddress(InetAddress.getByName(host));
+        super.send(dp);
+        return;
+     }
+
+     if(((Socks5Proxy)proxy).resolveAddrLocally){
+        dp.setAddress(InetAddress.getByName(host));
+     }
+
+     byte[] head = formHeader(host,dp.getPort());
+     byte[] buf = new byte[head.length + dp.getLength()];
+     byte[] data = dp.getData();
+     //Merge head and data
+     System.arraycopy(head,0,buf,0,head.length);
+     //System.arraycopy(data,dp.getOffset(),buf,head.length,dp.getLength());
+     System.arraycopy(data,0,buf,head.length,dp.getLength());
+
+     if(encapsulation != null)
+        buf = encapsulation.udpEncapsulate(buf,true);
+
+     super.send(new DatagramPacket(buf,buf.length,relayIP,relayPort));
+   }
+
+   /**
+    * Receives udp packet. If packet have arrived from the proxy relay server,
+    * it is processed and address and port of the packet are set to the
+    * address and port of sending host.<BR>
+    * If the packet arrived from anywhere else it is not changed.<br>
+    * <B> NOTE: </B> DatagramPacket size should be at least 10 bytes bigger
+    * than the largest packet you expect (this is for IPV4 addresses). 
+    * For hostnames and IPV6 it is even more.
+      @param dp Datagram in which all relevent information will be copied.
+    */
+   public void receive(DatagramPacket dp) throws IOException{
+      super.receive(dp);
+
+      if(server_mode){
+        //Drop all datagrams not from relayIP/relayPort
+         int init_length = dp.getLength();
+         int initTimeout = getSoTimeout();
+         long startTime = System.currentTimeMillis();
+
+         while(!relayIP.equals(dp.getAddress()) ||
+                relayPort != dp.getPort()){
+
+           //Restore datagram size
+           dp.setLength(init_length);
+
+           //If there is a non-infinit timeout on this socket
+           //Make sure that it happens no matter how often unexpected
+           //packets arrive.
+           if(initTimeout != 0){
+             int newTimeout = initTimeout - (int)(System.currentTimeMillis() - 
+                                                        startTime);
+             if(newTimeout <= 0) throw new InterruptedIOException(
+                                 "In Socks5DatagramSocket->receive()");
+             setSoTimeout(newTimeout);
+           }
+
+           super.receive(dp);
+         }
+
+         //Restore timeout settings
+         if(initTimeout != 0) setSoTimeout(initTimeout);
+
+      }else if(!relayIP.equals(dp.getAddress()) ||
+                relayPort != dp.getPort()) 
+          return; // Recieved direct packet
+      //If the datagram is not from the relay server, return it it as is.
+
+      byte[] data;
+      data = dp.getData();
+
+      if(encapsulation != null)
+         data = encapsulation.udpEncapsulate(data,false);
+
+      int offset = 0; //Java 1.1
+      //int offset = dp.getOffset(); //Java 1.2
+
+      ByteArrayInputStream bIn = new ByteArrayInputStream(data,offset,
+                                                              dp.getLength());
+
+
+      ProxyMessage msg = new Socks5Message(bIn);
+      dp.setPort(msg.port);
+      dp.setAddress(msg.getInetAddress());
+
+      //what wasn't read by the Message is the data
+      int data_length = bIn.available();
+      //Shift data to the left
+      System.arraycopy(data,offset+dp.getLength()-data_length,
+                       data,offset,data_length);
+
+
+      dp.setLength(data_length);
+   }
+
+   /**
+    * Returns port assigned by the proxy, to which datagrams are relayed.
+    * It is not the same port to which other party should send datagrams.
+      @return Port assigned by socks server to which datagrams are send
+      for association.
+    */
+   public int getLocalPort(){
+     if(server_mode) return super.getLocalPort();
+     return relayPort;
+   }
+   /**
+    * Address assigned by the proxy, to which datagrams are send for relay.
+    * It is not necesseraly the same address, to which other party should send
+    * datagrams.
+      @return Address to which datagrams are send for association.
+    */
+   public InetAddress getLocalAddress(){
+     if(server_mode) return super.getLocalAddress();
+     return relayIP;
+   }
+
+   /**
+    * Closes datagram socket, and proxy connection.
+    */
+   public void close(){
+      if(!server_mode) proxy.endSession();
+      super.close();
+   }
+
+   /**
+     This method checks wether proxy still runs udp forwarding service
+     for this socket.
+     <p>
+     This methods checks wether the primary connection to proxy server
+     is active. If it is, chances are that proxy continues to forward
+     datagrams being send from this socket. If it was closed, most likely
+     datagrams are no longer being forwarded by the server.
+     <p>
+     CProxy might decide to stop forwarding datagrams, in which case it
+     should close primary connection. This method allows to check, wether
+     this have been done.
+     <p>
+     You can specify timeout for which we should be checking EOF condition
+     on the primary connection. Timeout is in milliseconds. Specifying 0 as
+     timeout implies infinity, in which case method will block, until 
+     connection to proxy is closed or an error happens, and then return false.
+     <p>
+     One possible scenario is to call isProxyactive(0) in separate thread,
+     and once it returned notify other threads about this event.
+
+     @param timeout For how long this method should block, before returning.
+     @return true if connection to proxy is active, false if eof or error
+             condition have been encountered on the connection.
+   */
+   public boolean isProxyAlive(int timeout){
+     if(server_mode) return false;
+     if(proxy != null){
+         try{
+           proxy.proxySocket.setSoTimeout(timeout);
+
+           int eof = proxy.in.read();
+           if(eof < 0) return false; // EOF encountered.
+           else return true;         // This really should not happen
+
+         }catch(InterruptedIOException iioe){
+            return true;          // read timed out.
+         }catch(IOException ioe){
+            return false;
+         }
+     }
+     return false;
+   }
+
+//PRIVATE METHODS
+//////////////////
+
+
+   private byte[] formHeader(InetAddress ip, int port){
+      Socks5Message request = new Socks5Message(0,ip,port);
+      request.data[0] = 0;
+      return request.data;
+   }
+
+
+   private byte[] formHeader(String host,int port){
+      Socks5Message request = new Socks5Message(0,host,port);
+      request.data[0] = 0;
+      return request.data;
+   }
+
+
+/*======================================================================
+
+//Mainly Test functions
+//////////////////////
+
+   private String bytes2String(byte[] b){
+      String s="";
+      char[] hex_digit = { '0','1','2','3','4','5','6','7','8','9',
+                           'A','B','C','D','E','F'}; 
+      for(int i=0;i<b.length;++i){
+          int i1 = (b[i] & 0xF0) >> 4;
+          int i2 = b[i] & 0xF;
+          s+=hex_digit[i1];
+          s+=hex_digit[i2];
+          s+=" ";
+      }
+      return s;
+   }
+   private static final void debug(String s){
+      if(DEBUG)
+         System.out.print(s);
+   }
+
+   private static final boolean DEBUG = true;
+
+
+   public static void usage(){
+      System.err.print(
+    "Usage: java Socks.SocksDatagramSocket host port [socksHost socksPort]\n");
+   }
+
+   static final int defaultProxyPort = 1080;           //Default Port
+   static final String defaultProxyHost = "www-proxy"; //Default proxy
+
+   public static void main(String args[]){
+      int port;
+      String host;
+      int proxyPort;
+      String proxyHost;
+      InetAddress ip;
+
+      if(args.length > 1 && args.length < 5){
+	 try{
+
+	     host = args[0];
+	     port = Integer.parseInt(args[1]);
+
+	     proxyPort =(args.length > 3)? Integer.parseInt(args[3])	     
+	                                 : defaultProxyPort;
+
+	     host = args[0];
+	     ip = InetAddress.getByName(host);
+
+	     proxyHost =(args.length > 2)? args[2]
+	                                 : defaultProxyHost;
+
+	     CProxy.setDefaultProxy(proxyHost,proxyPort);
+	     CProxy p = CProxy.getDefaultProxy();
+	     p.addDirect("lux");
+
+
+	     DatagramSocket ds = new Socks5DatagramSocket();
+	                             
+
+	     BufferedReader in = new BufferedReader(
+				 new InputStreamReader(System.in));
+             String s;
+
+             System.out.print("Enter line:");
+             s = in.readLine();
+
+	     while(s != null){
+                byte[] data = (s+"\r\n").getBytes();
+                DatagramPacket dp = new DatagramPacket(data,0,data.length,
+                                        ip,port);
+                System.out.println("Sending to: "+ip+":"+port);
+                ds.send(dp);
+	        dp = new DatagramPacket(new byte[1024],1024);
+
+	        System.out.println("Trying to recieve on port:"+
+	                            ds.getLocalPort());
+	        ds.receive(dp);
+	        System.out.print("Recieved:\n"+
+	                         "From:"+dp.getAddress()+":"+dp.getPort()+
+	                         "\n\n"+
+                new String(dp.getData(),dp.getOffset(),dp.getLength())+"\n"
+                );
+                System.out.print("Enter line:");
+                s = in.readLine();
+
+	     }
+	     ds.close();
+	     System.exit(1);
+
+	 }catch(SocksException s_ex){
+	   System.err.println("SocksException:"+s_ex);
+	   s_ex.printStackTrace();
+	   System.exit(1); 
+	 }catch(IOException io_ex){
+	   io_ex.printStackTrace();
+	   System.exit(1);
+	 }catch(NumberFormatException num_ex){
+	   usage();
+	   num_ex.printStackTrace();
+	   System.exit(1);
+	 }
+
+      }else{
+	usage();
+      }
+   }
+*/
+
+}