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/*
* Copyright (c) 2010, Manuel Mausz. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - The names of the authors may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
import java.io.*;
import javax.crypto.*;
import java.util.Collection;
import java.util.Iterator;
import org.bouncycastle.util.encoders.Base64;
import java.security.GeneralSecurityException;
/*
* Common static methods used by all applications
*
* @author Manuel Mausz (0728348)
*/
class Utils
{
static class Shutdown
extends java.lang.RuntimeException
{
public Shutdown()
{
super();
}
public Shutdown(String message)
{
super(message);
}
}
/*==========================================================================*/
private static final String B64 = "a-zA-Z0-9/+";
/*==========================================================================*/
public static <T> String join(final Collection<T> objs, final String delimiter)
{
if (objs == null || objs.isEmpty())
return "";
Iterator<T> iter = objs.iterator();
StringBuffer buffer = new StringBuffer(iter.next().toString());
while (iter.hasNext())
buffer.append(delimiter).append(iter.next().toString());
return buffer.toString();
}
/*--------------------------------------------------------------------------*/
public static long parseHeaderNum(String[] args, int index)
{
long num = -1;
try
{
if (args.length < index + 1)
throw new NumberFormatException();
num = Long.parseLong(args[index]);
if (num < 0)
throw new NumberFormatException();
}
catch(NumberFormatException e)
{
System.err.println("Error: Invalid network paket from peer:");
System.err.println(join(java.util.Arrays.asList(args), " "));
}
return num;
}
/*------------------------------------------------------------------------*/
public static void sendOutput(EncObjectOutputStream out, String[] msgs)
throws IOException
{
out.writeLine("!output " + msgs.length);
for(String msg : msgs)
out.writeLine("!" + msg);
out.flush();
}
/*------------------------------------------------------------------------*/
public static void sendOutput(EncObjectOutputStream out, String msg)
throws IOException
{
String[] tmp = { msg };
sendOutput(out, tmp);
}
/*------------------------------------------------------------------------*/
public static void sendError(EncObjectOutputStream out, String[] msgs)
throws IOException
{
out.writeLine("!error " + msgs.length);
for(String msg : msgs)
out.writeLine("!" + msg);
out.flush();
}
/*------------------------------------------------------------------------*/
public static void sendError(EncObjectOutputStream out, String msg)
throws IOException
{
String[] tmp = { "Error: " + msg };
sendError(out, tmp);
}
/*==========================================================================*/
static class EncObjectInputStream
extends ObjectInputStream
{
private Cipher cipher = null;
private Mac mac = null;
public EncObjectInputStream(InputStream in)
throws IOException
{
super(in);
}
/*------------------------------------------------------------------------*/
public void setCipher(Cipher cipher)
{
this.cipher = cipher;
}
/*------------------------------------------------------------------------*/
public void setMAC(Mac mac)
{
this.mac = mac;
}
/*------------------------------------------------------------------------*/
private String decode(String msg)
{
if (msg == null)
return null;
if ((cipher == null && mac == null) || msg.charAt(0) == '!')
return msg;
if (mac != null)
{
msg = new String(Base64.decode(msg));
assert msg.matches("[" + B64 + "]{43}= [\\s[^\\s]]+");
int ix = msg.indexOf(' ');
if (ix == -1)
{
System.err.println("Error: invalid hashed message format:");
System.err.println(msg);
return null;
}
String hasht = msg.substring(0, ix);
String msgtmp = msg.substring(ix + 1);
String hashc = new String(Base64.encode(mac.doFinal(msgtmp.getBytes())));
if (!hasht.equals(hashc))
{
System.err.println("Error: invalid MAC:");
System.err.println(msg);
throw new HashError();
//return null;
}
msg = msgtmp;
}
if (cipher != null)
{
try
{
byte[] decmsg = Base64.decode(msg);
return new String(cipher.doFinal(decmsg));
}
catch(GeneralSecurityException e)
{
System.err.println("Error: Unable to decode message: " + e.getMessage());
return null;
}
}
return msg;
}
/*------------------------------------------------------------------------*/
public String readUTF()
throws IOException
{
return decode(super.readUTF());
}
/*------------------------------------------------------------------------*/
@SuppressWarnings("deprecation")
public String readLine()
throws IOException
{
return decode(super.readLine());
}
}
/*==========================================================================*/
static class EncObjectOutputStream
extends ObjectOutputStream
{
private Cipher cipher = null;
private Mac mac = null;
public EncObjectOutputStream(OutputStream out)
throws IOException
{
super(out);
}
/*------------------------------------------------------------------------*/
public void setCipher(Cipher cipher)
{
this.cipher = cipher;
}
/*------------------------------------------------------------------------*/
public void setMAC(Mac mac)
{
this.mac = mac;
}
/*------------------------------------------------------------------------*/
private byte[] encode(byte[] msg)
{
try
{
return Base64.encode(cipher.doFinal(msg));
}
catch(GeneralSecurityException e)
{
System.err.println("Error: Unable to encode message: " + e.getMessage());
}
return null;
}
/*------------------------------------------------------------------------*/
public void writeUTF(String msg)
throws IOException
{
if (cipher == null && mac == null)
{
super.writeUTF(msg);
return;
}
if (mac != null)
{
byte[] hash = mac.doFinal(msg.getBytes());
msg = new String(Base64.encode(hash)) + " " + msg;
assert msg.matches("[" + B64 + "]{43}= [\\s[^\\s]]+");
}
if (cipher != null)
{
super.writeUTF(new String(encode(msg.getBytes())));
return;
}
String hashedmsg = new String(Base64.encode(msg.getBytes()));
super.writeUTF(hashedmsg);
return;
}
/*------------------------------------------------------------------------*/
public void writeLine(String msg)
throws IOException
{
if (cipher == null && mac == null)
{
super.writeBytes(msg + "\n");
return;
}
if (mac != null)
{
byte[] hash = mac.doFinal(msg.getBytes());
msg = new String(Base64.encode(hash)) + " " + msg;
assert msg.matches("[" + B64 + "]{43}= [\\s[^\\s]]+");
}
if (cipher != null)
{
super.writeBytes(new String(encode(msg.getBytes())) + "\n");
return;
}
super.writeBytes(new String(Base64.encode(msg.getBytes())) + "\n");
return;
}
}
/*==========================================================================*/
static class HashError
extends java.lang.RuntimeException
{
public HashError()
{
super();
}
}
}