--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/src/main/java/net/sourceforge/jsocks/ProxyServer.java	Thu Dec 03 11:23:55 2015 -0800
@@ -0,0 +1,604 @@
+package net.sourceforge.jsocks;
+import net.sourceforge.jsocks.server.ServerAuthenticator;
+import java.net.*;
+import java.io.*;
+
+/**
+    SOCKS4 and SOCKS5 proxy, handles both protocols simultaniously.
+    Implements all SOCKS commands, including UDP relaying.
+    <p>
+    In order to use it you will need to implement ServerAuthenticator
+    interface. There is an implementation of this interface which does
+    no authentication ServerAuthenticatorNone, but it is very dangerous
+    to use, as it will give access to your local network to anybody
+    in the world. One should never use this authentication scheme unless
+    one have pretty good reason to do so.
+    There is a couple of other authentication schemes in socks.server package.
+    @see socks.server.ServerAuthenticator
+*/
+public class ProxyServer implements Runnable{
+
+   ServerAuthenticator auth;
+   ProxyMessage msg = null;
+
+   Socket sock=null,remote_sock=null;
+   ServerSocket ss=null;
+   UDPRelayServer relayServer = null;
+   InputStream in,remote_in;
+   OutputStream out,remote_out;
+
+   int mode;
+   static final int START_MODE	= 0;
+   static final int ACCEPT_MODE	= 1;
+   static final int PIPE_MODE	= 2;
+   static final int ABORT_MODE	= 3;
+
+   static final int BUF_SIZE	= 8192;
+
+   Thread pipe_thread1,pipe_thread2;
+   long lastReadTime;
+
+   static int iddleTimeout	= 180000; //3 minutes
+   static int acceptTimeout	= 180000; //3 minutes
+
+   static PrintStream log = null;
+   static CProxy proxy;
+
+
+//Public Constructors
+/////////////////////
+
+
+   /**
+    Creates a proxy server with given Authentication scheme.
+    @param auth Authentication scheme to be used.
+    */
+   public ProxyServer(ServerAuthenticator auth){
+     this.auth = auth;
+   }
+
+//Other constructors
+////////////////////
+
+   ProxyServer(ServerAuthenticator auth,Socket s){
+      this.auth  = auth;
+      this.sock  = s;
+      mode = START_MODE;
+   }
+
+//Public methods
+/////////////////
+
+   /**
+     Set the logging stream. Specifying null disables logging.
+   */
+   public static void setLog(OutputStream out){
+      if(out == null){
+        log = null;
+      }else{
+        log = new PrintStream(out,true);
+      }
+
+      UDPRelayServer.log = log;
+   }
+   
+   /**
+    Set proxy.
+    <p>
+    Allows CProxy chaining so that one CProxy server is connected to another
+    and so on. If proxy supports SOCKSv4, then only some SOCKSv5 requests
+    can be handled, UDP would not work, however CONNECT and BIND will be
+    translated.
+
+    @param p CProxy which should be used to handle user requests.
+   */
+   public static void setProxy(CProxy p){
+      proxy =p;
+      UDPRelayServer.proxy = proxy;
+   }
+
+   /**
+    Get proxy.
+    @return CProxy wich is used to handle user requests.
+   */
+   public static CProxy getProxy(){
+      return proxy;
+   }
+
+   /**
+    Sets the timeout for connections, how long shoud server wait
+    for data to arrive before dropping the connection.<br>
+    Zero timeout implies infinity.<br>
+    Default timeout is 3 minutes.
+   */
+   public static void setIddleTimeout(int timeout){
+      iddleTimeout = timeout;
+   }
+   /**
+    Sets the timeout for BIND command, how long the server should
+    wait for the incoming connection.<br>
+    Zero timeout implies infinity.<br>
+    Default timeout is 3 minutes.
+   */
+   public static void setAcceptTimeout(int timeout){
+      acceptTimeout = timeout;
+   }
+
+   /**
+    Sets the timeout for UDPRelay server.<br>
+    Zero timeout implies infinity.<br>
+    Default timeout is 3 minutes.
+   */
+   public static void setUDPTimeout(int timeout){
+      UDPRelayServer.setTimeout(timeout);
+   }
+
+   /**
+     Sets the size of the datagrams used in the UDPRelayServer.<br>
+     Default size is 64K, a bit more than maximum possible size of the
+     datagram.
+    */
+   public static void setDatagramSize(int size){
+      UDPRelayServer.setDatagramSize(size);
+   }
+
+
+   /**
+     Start the CProxy server at given port.<br>
+     This methods blocks.
+    */
+   public void start(int port){
+      start(port,5,null);
+   }
+
+   /**
+     Create a server with the specified port, listen backlog, and local 
+     IP address to bind to. The localIP argument can be used on a multi-homed
+     host for a ServerSocket that will only accept connect requests to one of 
+     its addresses. If localIP is null, it will default accepting connections 
+     on any/all local addresses. The port must be between 0 and 65535, 
+     inclusive. <br>
+     This methods blocks. 
+    */
+   public void start(int port,int backlog,InetAddress localIP){
+      try{
+        ss = new ServerSocket(port,backlog,localIP);
+        log("Starting SOCKS Proxy on:"+ss.getInetAddress().getHostAddress()+":"
+                                      +ss.getLocalPort());
+        while(true){
+          Socket s = ss.accept();
+          log("Accepted from:"+s.getInetAddress().getHostName()+":"
+                              +s.getPort());
+          ProxyServer ps = new ProxyServer(auth,s);
+          (new Thread(ps)).start();
+        }
+      }catch(IOException ioe){
+        ioe.printStackTrace();
+      }finally{
+      }
+   }
+
+   /**
+     Stop server operation.It would be wise to interrupt thread running the
+     server afterwards.
+    */
+   public void stop(){
+     try{
+       if(ss != null) ss.close();
+     }catch(IOException ioe){
+     }
+   }
+
+//Runnable interface
+////////////////////
+   public void run(){
+      switch(mode){
+        case START_MODE:
+         try{
+           startSession();
+         }catch(IOException ioe){
+           handleException(ioe);
+           //ioe.printStackTrace();
+         }finally{
+           abort();
+           if(auth!=null) auth.endSession();
+           log("Main thread(client->remote)stopped.");
+         }
+        break;
+        case ACCEPT_MODE:
+          try{
+            doAccept();
+            mode = PIPE_MODE;
+            pipe_thread1.interrupt(); //Tell other thread that connection have
+                                      //been accepted.
+            pipe(remote_in,out);
+          }catch(IOException ioe){
+            //log("Accept exception:"+ioe);
+            handleException(ioe);
+          }finally{
+            abort();
+            log("Accept thread(remote->client) stopped");
+          }
+        break;
+        case PIPE_MODE:
+         try{
+            pipe(remote_in,out);
+         }catch(IOException ioe){
+         }finally{
+            abort();
+            log("Support thread(remote->client) stopped");
+         }
+        break;
+        case ABORT_MODE:
+        break;
+        default:
+         log("Unexpected MODE "+mode);
+      }
+   }
+
+//Private methods
+/////////////////
+   private void startSession() throws IOException{
+     sock.setSoTimeout(iddleTimeout);
+
+     try{
+        auth = auth.startSession(sock);
+     }catch(IOException ioe){
+       log("Auth throwed exception:"+ioe);
+       auth = null;
+       return;
+     }
+
+     if(auth == null){ //Authentication failed
+        log("Authentication failed");
+        return;
+     }
+
+     in = auth.getInputStream();
+     out = auth.getOutputStream();
+
+     msg = readMsg(in);
+     handleRequest(msg);
+   }
+   
+   private void handleRequest(ProxyMessage msg)
+                throws IOException{
+      if(!auth.checkRequest(msg)) throw new 
+                                  SocksException(CProxy.SOCKS_FAILURE);
+
+      if(msg.ip == null){
+        if(msg instanceof Socks5Message){
+          msg.ip = InetAddress.getByName(msg.host);
+        }else
+          throw new SocksException(CProxy.SOCKS_FAILURE);
+      }
+      log(msg);
+
+      switch(msg.command){
+        case CProxy.SOCKS_CMD_CONNECT:
+          onConnect(msg);
+        break;
+        case CProxy.SOCKS_CMD_BIND:
+          onBind(msg);
+        break;
+        case CProxy.SOCKS_CMD_UDP_ASSOCIATE:
+          onUDP(msg);
+        break;
+        default:
+          throw new SocksException(CProxy.SOCKS_CMD_NOT_SUPPORTED);
+      }
+   }
+
+   private void handleException(IOException ioe){
+      //If we couldn't read the request, return;
+      if(msg == null) return;
+      //If have been aborted by other thread
+      if(mode == ABORT_MODE) return;
+      //If the request was successfully completed, but exception happened later
+      if(mode == PIPE_MODE) return;
+
+      int error_code = CProxy.SOCKS_FAILURE;
+
+      if(ioe instanceof SocksException)
+          error_code = ((SocksException)ioe).errCode;
+      else if(ioe instanceof NoRouteToHostException)
+          error_code = CProxy.SOCKS_HOST_UNREACHABLE;
+      else if(ioe instanceof ConnectException)
+          error_code = CProxy.SOCKS_CONNECTION_REFUSED;
+      else if(ioe instanceof InterruptedIOException)
+          error_code = CProxy.SOCKS_TTL_EXPIRE;
+
+      if(error_code > CProxy.SOCKS_ADDR_NOT_SUPPORTED || error_code < 0){
+          error_code = CProxy.SOCKS_FAILURE;
+      }
+
+      sendErrorMessage(error_code);
+   }
+
+    private void onConnect(ProxyMessage msg) throws IOException {
+        Socket s = null;
+        ProxyMessage response = null;
+        int iSock5Cmd = CProxy.SOCKS_FAILURE;    //defaulting to failure
+        int iSock4Msg = Socks4Message.REPLY_NO_CONNECT;
+        InetAddress sIp = null; int iPort = 0;
+
+        try {
+            if (proxy == null) {
+                s = new Socket(msg.ip, msg.port);
+            } else {
+                s = new SocksSocket(proxy, msg.ip, msg.port);
+            }
+            log("Connected to " + s.getInetAddress() + ":" + s.getPort());
+
+            iSock5Cmd = CProxy.SOCKS_SUCCESS; iSock4Msg = Socks4Message.REPLY_OK;
+            sIp = s.getInetAddress(); iPort = s.getPort();
+
+        }
+        catch (Exception sE) {
+            log("Failed connecting to remote socket. Exception: " + sE.getLocalizedMessage());
+
+            //TBD Pick proper socks error for corresponding socket error, below is too generic
+            iSock5Cmd = CProxy.SOCKS_CONNECTION_REFUSED; iSock4Msg = Socks4Message.REPLY_NO_CONNECT;
+        }
+
+        if (msg instanceof Socks5Message) {
+            response = new Socks5Message(iSock5Cmd, sIp, iPort);
+        } else {
+            response = new Socks4Message(iSock4Msg, sIp, iPort);
+        }
+
+        response.write(out);
+
+        if (s != null) {
+            startPipe(s);
+        }
+        else {
+            throw (new RuntimeException("onConnect() Failed to create Socket()"));
+        }
+
+        return;
+    }
+
+
+   private void onBind(ProxyMessage msg) throws IOException{
+      ProxyMessage response = null;
+
+      if(proxy == null)
+        ss = new ServerSocket(0);
+      else
+        ss = new SocksServerSocket(proxy, msg.ip, msg.port);
+
+      ss.setSoTimeout(acceptTimeout);
+
+      log("Trying accept on "+ss.getInetAddress()+":"+ss.getLocalPort());
+
+      if(msg.version == 5)
+         response = new Socks5Message(CProxy.SOCKS_SUCCESS,ss.getInetAddress(),
+                                                          ss.getLocalPort());
+      else
+         response = new Socks4Message(Socks4Message.REPLY_OK,
+                                      ss.getInetAddress(),
+                                      ss.getLocalPort());
+      response.write(out);
+
+      mode = ACCEPT_MODE;
+
+      pipe_thread1 = Thread.currentThread();
+      pipe_thread2 = new Thread(this);
+      pipe_thread2.start();
+
+      //Make timeout infinit.
+      sock.setSoTimeout(0);
+      int eof=0;
+
+      try{
+        while((eof=in.read())>=0){
+          if(mode != ACCEPT_MODE){
+            if(mode != PIPE_MODE) return;//Accept failed
+
+            remote_out.write(eof);
+            break;
+          }
+        }
+      }catch(EOFException eofe){
+        //System.out.println("EOF exception");
+        return;//Connection closed while we were trying to accept.
+      }catch(InterruptedIOException iioe){ 
+        //Accept thread interrupted us.
+        //System.out.println("Interrupted");
+        if(mode != PIPE_MODE)
+          return;//If accept thread was not successfull return.
+      }finally{
+        //System.out.println("Finnaly!");
+      }
+
+      if(eof < 0)//Connection closed while we were trying to accept;
+        return;
+      
+      //Do not restore timeout, instead timeout is set on the
+      //remote socket. It does not make any difference.
+
+      pipe(in,remote_out);
+   }
+
+   private void onUDP(ProxyMessage msg) throws IOException{
+      if(msg.ip.getHostAddress().equals("0.0.0.0"))
+         msg.ip = sock.getInetAddress();
+      log("Creating UDP relay server for "+msg.ip+":"+msg.port);
+      relayServer = new UDPRelayServer(msg.ip,msg.port,
+                        Thread.currentThread(),sock,auth);
+
+      ProxyMessage response;
+
+      response = new Socks5Message(CProxy.SOCKS_SUCCESS,
+                                   relayServer.relayIP,relayServer.relayPort);
+
+      response.write(out);
+
+      relayServer.start();
+
+      //Make timeout infinit.
+      sock.setSoTimeout(0);
+      try{
+        while(in.read()>=0) /*do nothing*/;
+      }catch(EOFException eofe){
+      }
+   }
+
+//Private methods
+//////////////////
+
+   private void doAccept() throws IOException{
+      Socket s;
+      long startTime = System.currentTimeMillis();
+
+      while(true){
+         s = ss.accept();
+         if(s.getInetAddress().equals(msg.ip)){
+            //got the connection from the right host
+            //Close listenning socket.
+            ss.close();
+            break;
+         }else if(ss instanceof SocksServerSocket){
+            //We can't accept more then one connection
+            s.close();
+            ss.close();
+            throw new SocksException(CProxy.SOCKS_FAILURE);
+         }else{
+            if(acceptTimeout!=0){ //If timeout is not infinit
+               int newTimeout = acceptTimeout-(int)(System.currentTimeMillis()-
+                                                           startTime);
+               if(newTimeout <= 0) throw new InterruptedIOException(
+                                "In doAccept()");
+               ss.setSoTimeout(newTimeout);
+            }
+            s.close(); //Drop all connections from other hosts
+         }
+      }
+
+      //Accepted connection
+      remote_sock = s;
+      remote_in = s.getInputStream();
+      remote_out = s.getOutputStream();
+
+      //Set timeout
+      remote_sock.setSoTimeout(iddleTimeout);
+
+      log("Accepted from "+s.getInetAddress()+":"+s.getPort());
+
+      ProxyMessage response;
+
+      if(msg.version == 5)
+         response = new Socks5Message(CProxy.SOCKS_SUCCESS, s.getInetAddress(),
+                                                           s.getPort());
+      else
+         response = new Socks4Message(Socks4Message.REPLY_OK,
+                                      s.getInetAddress(), s.getPort());
+      response.write(out);
+   }
+
+   private ProxyMessage readMsg(InputStream in) throws IOException{
+      PushbackInputStream push_in;  
+      if(in instanceof PushbackInputStream)
+         push_in = (PushbackInputStream) in;
+      else
+         push_in = new PushbackInputStream(in);
+
+      int version = push_in.read();
+      push_in.unread(version);
+
+
+      ProxyMessage msg;
+
+      if(version == 5){
+        msg = new Socks5Message(push_in,false);
+      }else if(version == 4){
+        msg = new Socks4Message(push_in,false);
+      }else{
+        throw new SocksException(CProxy.SOCKS_FAILURE);
+      }
+      return msg;
+   }
+
+   private void startPipe(Socket s){
+      mode = PIPE_MODE;
+      remote_sock = s;
+      try{
+         remote_in = s.getInputStream();
+         remote_out = s.getOutputStream();
+         pipe_thread1 = Thread.currentThread();
+         pipe_thread2 = new Thread(this);
+         pipe_thread2.start();
+         pipe(in,remote_out);
+      }catch(IOException ioe){
+      }
+   }
+
+   private void sendErrorMessage(int error_code){
+      ProxyMessage err_msg;
+      if(msg instanceof Socks4Message)
+         err_msg = new Socks4Message(Socks4Message.REPLY_REJECTED);
+      else
+         err_msg = new Socks5Message(error_code);
+      try{
+         err_msg.write(out);
+      }catch(IOException ioe){}
+   }
+
+   private synchronized void abort(){
+      if(mode == ABORT_MODE) return;
+      mode = ABORT_MODE;
+      try{
+         log("Aborting operation");
+         if(remote_sock != null) remote_sock.close();
+         if(sock != null) sock.close();
+         if(relayServer!=null) relayServer.stop();
+         if(ss!=null) ss.close();
+         if(pipe_thread1 != null) pipe_thread1.interrupt();
+         if(pipe_thread2 != null) pipe_thread2.interrupt();
+      }catch(IOException ioe){}
+   }
+
+   static final void log(String s){
+     if(log != null){
+       log.println(s);
+       log.flush();
+     }
+   }
+
+   static final void log(ProxyMessage msg){
+      log("Request version:"+msg.version+
+          "\tCommand: "+command2String(msg.command));
+      log("IP:"+msg.ip +"\tPort:"+msg.port+
+         (msg.version==4?"\tUser:"+msg.user:""));
+   }
+
+   private void pipe(InputStream in,OutputStream out) throws IOException{
+      lastReadTime = System.currentTimeMillis();
+      byte[] buf = new byte[BUF_SIZE];
+      int len = 0;
+      while(len >= 0){
+         try{
+           if(len!=0){
+             out.write(buf,0,len);
+             out.flush();
+           }
+           len= in.read(buf);
+           lastReadTime = System.currentTimeMillis();
+         }catch(InterruptedIOException iioe){
+           if(iddleTimeout == 0) return;//Other thread interrupted us.
+           long timeSinceRead = System.currentTimeMillis() - lastReadTime;
+           if(timeSinceRead >= iddleTimeout - 1000) //-1s for adjustment.
+              return;
+           len = 0;
+
+         }
+      }
+   }
+   static final String command_names[] = {"CONNECT","BIND","UDP_ASSOCIATE"};
+
+   static final String command2String(int cmd){
+      if(cmd > 0 && cmd < 4) return command_names[cmd-1];
+      else return "Unknown Command "+cmd;
+   }
+}