--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/net/sourceforge/jsocks/Socks4Message.java	Thu May 22 10:41:19 2014 -0700
@@ -0,0 +1,182 @@
+package net.sourceforge.jsocks;
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+/**
+  SOCKS4 Reply/Request message.
+*/
+
+public class Socks4Message extends ProxyMessage {
+
+    private byte[] msgBytes;
+    private int msgLength;
+
+    /**
+     * Server failed reply, cmd command for failed request
+     */
+    public Socks4Message(int cmd) {
+        super(cmd, null, 0);
+        this.user    = null;
+        msgLength = 2;
+        msgBytes = new byte[2];
+        msgBytes[0] = (byte) 0;
+        msgBytes[1] = (byte) command;
+    }
+
+    /**
+     *  Server successfull reply
+     */
+    public Socks4Message(int cmd, InetAddress ip, int port) {
+        this(0, cmd, ip, port, null);
+    }
+
+    /**
+     *  Client request
+     */
+    public Socks4Message(int cmd, InetAddress ip, int port, String user) {
+        this(SOCKS_VERSION, cmd, ip, port, user);
+    }
+
+    /**
+     * Most general constructor
+     */
+    public Socks4Message(int version, int cmd,
+                         InetAddress ip, int port, String user) {
+        super(cmd, ip, port);
+        this.user    = user;
+        this.version = version;
+        msgLength = user == null ? 8 : 9 + user.length();
+        msgBytes = new byte[msgLength];
+        msgBytes[0] = (byte) version;
+        msgBytes[1] = (byte) command;
+        msgBytes[2] = (byte)(port >> 8);
+        msgBytes[3] = (byte) port;
+        byte[] addr;
+
+        if (ip != null)
+            addr = ip.getAddress();
+        else {
+            addr = new byte[4];
+            addr[0] = addr[1] = addr[2] = addr[3] = 0;
+        }
+
+        System.arraycopy(addr, 0, msgBytes, 4, 4);
+
+        if (user != null) {
+            byte[] buf = user.getBytes();
+            System.arraycopy(buf, 0, msgBytes, 8, buf.length);
+            msgBytes[msgBytes.length - 1 ] = 0;
+        }
+    }
+
+    /**
+     *Initialise from the stream
+     *If clientMode is true attempts to read a server response
+     *otherwise reads a client request
+     *see read for more detail
+     */
+    public Socks4Message(InputStream in, boolean clientMode) throws IOException {
+        msgBytes = null;
+        read(in, clientMode);
+    }
+
+    @Override
+    public void read(InputStream in) throws IOException {
+        read(in, true);
+    }
+
+    @Override
+    public void read(InputStream in, boolean clientMode) throws IOException {
+        boolean mode4a = false;
+        DataInputStream d_in = new DataInputStream(in);
+        version = d_in.readUnsignedByte();
+        command = d_in.readUnsignedByte();
+
+        if (clientMode && command != REPLY_OK) {
+            String errMsg;
+
+            if (command > REPLY_OK && command < REPLY_BAD_IDENTD)
+                errMsg = replyMessage[command - REPLY_OK];
+            else
+                errMsg = "Unknown Reply Code";
+
+            throw new SocksException(command, errMsg);
+        }
+
+        port = d_in.readUnsignedShort();
+        byte[] addr = new byte[4];
+        d_in.readFully(addr);
+
+        if (addr[0] == 0 && addr[1] == 0 && addr[2] == 0 && addr[3] != 0)
+            mode4a = true;
+        else {
+            ip = bytes2IP(addr);
+            host = ip.getHostName();
+        }
+
+        if (!clientMode) {
+            StringBuilder sb = new StringBuilder();
+            int b;
+
+            while ((b = in.read()) != 0)
+                sb.append((char) b);
+
+            user = sb.toString();
+
+            if (mode4a) {
+                sb.setLength(0);
+
+                while ((b = in.read()) != 0)
+                    sb.append((char) b);
+
+                host = sb.toString();
+            }
+        }
+    }
+    @Override
+    public void write(OutputStream out) throws IOException {
+        if (msgBytes == null) {
+            Socks4Message msg = new Socks4Message(version, command, ip, port, user);
+            msgBytes = msg.msgBytes;
+            msgLength = msg.msgLength;
+        }
+
+        out.write(msgBytes);
+    }
+
+    //Class methods
+    static InetAddress bytes2IP(byte[] addr) {
+        String s = bytes2IPV4(addr, 0);
+
+        try {
+            return InetAddress.getByName(s);
+        }
+        catch (UnknownHostException uh_ex) {
+            return null;
+        }
+    }
+
+    //Constants
+
+    static final String[] replyMessage = {
+        "Request Granted",
+        "Request Rejected or Failed",
+        "Failed request, can't connect to Identd",
+        "Failed request, bad user name"
+    };
+
+    static final int SOCKS_VERSION = 4;
+
+    public final static int REQUEST_CONNECT      = 1;
+    public final static int REQUEST_BIND         = 2;
+
+    public final static int REPLY_OK             = 90;
+    public final static int REPLY_REJECTED       = 91;
+    public final static int REPLY_NO_CONNECT     = 92;
+    public final static int REPLY_BAD_IDENTD     = 93;
+
+}