--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/src/main/java/net/sourceforge/jsocks/server/ServerAuthenticator.java	Thu Dec 03 11:23:55 2015 -0800
@@ -0,0 +1,119 @@
+package net.sourceforge.jsocks.server;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.Socket;
+import java.net.DatagramPacket;
+import net.sourceforge.jsocks.ProxyMessage;
+import net.sourceforge.jsocks.UDPEncapsulation;
+
+/**
+ Classes implementing this interface should provide socks server with
+ authentication and authorization of users.
+**/
+public interface ServerAuthenticator{
+
+   /**
+     This method is called when a new connection accepted by the server.
+     <p>
+     At this point no data have been extracted from the connection. It is
+     responsibility of this method to ensure that the next byte in the
+     stream after this method have been called is the first byte of the
+     socks request message. For SOCKSv4 there is no authentication data and
+     the first byte in the stream is part of the request. With SOCKSv5 however
+     there is an authentication data first. It is expected that implementaions
+     will process this authentication data. 
+     <p>
+     If authentication was successful an instance of ServerAuthentication
+     should be returned, it later will be used by the server to perform
+     authorization and some other things. If authentication fails null should
+     be returned, or an exception may be thrown.
+
+     @param s Accepted Socket.
+     @return An instance of ServerAuthenticator to be used for this connection
+     or null
+   */
+   ServerAuthenticator startSession(Socket s) throws IOException;
+
+   /**
+    This method should return input stream which should be used on the
+    accepted socket.
+    <p>
+    SOCKSv5 allows to have multiple authentication methods, and these methods
+    might require some kind of transformations being made on the data.
+    <p>
+    This method is called on the object returned from the startSession
+    function.
+   */
+   InputStream getInputStream();
+   /**
+    This method should return output stream to use to write to the accepted
+    socket.
+    <p>
+    SOCKSv5 allows to have multiple authentication methods, and these methods
+    might require some kind of transformations being made on the data.
+    <p>
+    This method is called on the object returned from the startSession
+    function.
+   */
+   OutputStream getOutputStream();
+
+   /**
+    This method should return UDPEncapsulation, which should be used
+    on the datagrams being send in/out.
+    <p>
+    If no transformation should be done on the datagrams, this method
+    should return null.
+    <p>
+    This method is called on the object returned from the startSession
+    function.
+   */
+
+   UDPEncapsulation getUdpEncapsulation();
+
+   /**
+    This method is called when a request have been read.
+    <p>
+    Implementation should decide wether to grant request or not. Returning
+    true implies granting the request, false means request should be rejected.
+    <p>
+    This method is called on the object returned from the startSession
+    function.
+    @param msg Request message.
+    @return true to grant request, false to reject it.
+   */
+   boolean checkRequest(ProxyMessage msg);
+
+   /**
+    This method is called when datagram is received by the server.
+    <p>
+    Implementaions should decide wether it should be forwarded or dropped.
+    It is expecteed that implementation will use datagram address and port
+    information to make a decision, as well as anything else. Address and
+    port of the datagram are always correspond to remote machine. It is
+    either destination or source address. If out is true address is destination
+    address, else it is a source address, address of the machine from which
+    datagram have been received for the client.
+    <p>
+    Implementaions should return true if the datagram is to be forwarded, and
+    false if the datagram should be dropped.
+    <p>
+    This method is called on the object returned from the startSession
+    function.
+
+    @param out If true the datagram is being send out(from the client),
+               otherwise it is an incoming datagram.
+    @return True to forward datagram false drop it silently.
+   */
+   boolean checkRequest(DatagramPacket dp, boolean out);
+
+   /**
+    This method is called when session is completed. Either due to normal
+    termination or due to any error condition.
+    <p>
+    This method is called on the object returned from the startSession
+    function.
+   */
+   void endSession();
+}