From da6d73f5a5818b3cc874f7ed319014d591e101e8 Mon Sep 17 00:00:00 2001
From: Kenny Root <kenny@the-b.org>
Date: Sat, 8 Nov 2008 10:01:55 +0000
Subject: * Add dynamic port forwarding.

---
 .../jsocks/server/ServerAuthenticatorNone.java     | 169 +++++++++++++++++++++
 1 file changed, 169 insertions(+)
 create mode 100644 src/net/sourceforge/jsocks/server/ServerAuthenticatorNone.java

(limited to 'src/net/sourceforge/jsocks/server/ServerAuthenticatorNone.java')

diff --git a/src/net/sourceforge/jsocks/server/ServerAuthenticatorNone.java b/src/net/sourceforge/jsocks/server/ServerAuthenticatorNone.java
new file mode 100644
index 0000000..30eb265
--- /dev/null
+++ b/src/net/sourceforge/jsocks/server/ServerAuthenticatorNone.java
@@ -0,0 +1,169 @@
+package net.sourceforge.jsocks.server;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.PushbackInputStream;
+import java.net.Socket;
+
+import net.sourceforge.jsocks.ProxyMessage;
+import net.sourceforge.jsocks.UDPEncapsulation;
+
+/**
+ An implementation of ServerAuthenticator, which does <b>not</b> do
+ any authentication.
+<P>
+<FONT size="+3" color ="FF0000"> Warning!!</font><br> Should not be
+used on machines which are not behind the firewall.
+<p>
+It is only provided to make implementing other authentication schemes
+easier.<br>
+For Example: <tt><pre>
+   class MyAuth extends socks.server.ServerAuthenticator{
+    ...
+    public ServerAuthenticator startSession(java.net.Socket s){
+      if(!checkHost(s.getInetAddress()) return null;
+      return super.startSession(s);
+    }
+
+    boolean checkHost(java.net.Inetaddress addr){
+      boolean allow;
+      //Do it somehow
+      return allow;
+    }
+   }
+</pre></tt>
+*/
+public class ServerAuthenticatorNone implements ServerAuthenticator{
+
+   static final byte[] socks5response = {5,0};
+
+   InputStream in;
+   OutputStream out;
+
+   /**
+    Creates new instance of the ServerAuthenticatorNone.
+   */
+   public ServerAuthenticatorNone(){
+     this.in = null;
+     this.out = null;
+   }
+   /**
+    Constructs new ServerAuthenticatorNone object suitable for returning
+    from the startSession function.
+    @param in Input stream to return from getInputStream method.
+    @param out Output stream to return from getOutputStream method.
+   */
+   public ServerAuthenticatorNone(InputStream in, OutputStream out){
+      this.in = in;
+      this.out = out;
+   }
+   /**
+    Grants access to everyone.Removes authentication related bytes from
+    the stream, when a SOCKS5 connection is being made, selects an
+    authentication NONE.
+    */
+   public ServerAuthenticator startSession(Socket s)
+                                  throws IOException{
+
+     PushbackInputStream in =  new PushbackInputStream(s.getInputStream());
+     OutputStream out = s.getOutputStream();
+
+     int version = in.read();
+     if(version == 5){
+       if(!selectSocks5Authentication(in,out,0))
+          return null;
+     }else if(version == 4){
+       //Else it is the request message allready, version 4
+       in.unread(version);
+     }else
+       return null;
+     
+
+     return new ServerAuthenticatorNone(in,out);
+   }
+
+   /**
+     Get input stream.
+     @return Input stream speciefied in the constructor.
+   */
+   public InputStream getInputStream(){
+      return in;
+   }
+   /**
+     Get output stream.
+     @return Output stream speciefied in the constructor.
+   */
+   public OutputStream getOutputStream(){
+      return out;
+   }
+   /**
+     Allways returns null.
+     @return null
+   */
+   public UDPEncapsulation getUdpEncapsulation(){
+      return null;
+   }
+
+   /**
+    Allways returns true.
+   */
+   public boolean checkRequest(ProxyMessage msg){
+     return true;
+   }
+
+   /**
+    Allways returns true.
+   */
+   public boolean checkRequest(java.net.DatagramPacket dp, boolean out){
+     return true;
+   }
+
+   /**
+    Does nothing.
+    */
+   public void endSession(){
+   }
+
+   /**
+     Convinience routine for selecting SOCKSv5 authentication.
+     <p>
+     This method reads in authentication methods that client supports,
+     checks wether it supports given method. If it does, the notification
+     method is written back to client, that this method have been chosen
+     for authentication. If given method was not found, authentication
+     failure message is send to client ([5,FF]).
+     @param in Input stream, version byte should be removed from the stream
+               before calling this method.
+     @param out Output stream.
+     @param methodId Method which should be selected.
+     @return true if methodId was found, false otherwise.
+   */
+   static public boolean selectSocks5Authentication(InputStream in, 
+                                                    OutputStream out,
+                                                    int methodId)
+                                                    throws IOException{
+                                                    
+      int num_methods = in.read();
+      if (num_methods <= 0) return false;
+      byte method_ids[] = new byte[num_methods];
+      byte response[] = new byte[2];
+      boolean found = false;
+
+      response[0] = (byte) 5;    //SOCKS version
+      response[1] = (byte) 0xFF; //Not found, we are pessimistic
+
+      int bread = 0; //bytes read so far
+      while(bread < num_methods)
+         bread += in.read(method_ids,bread,num_methods-bread);
+
+      for(int i=0;i<num_methods;++i)
+         if(method_ids[i] == methodId){
+           found = true;
+           response[1] = (byte) methodId;
+           break;
+         }
+
+      out.write(response);
+      return found;
+   }
+}
-- 
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