inputOutputHandler
Class NextMixConnectionHandler

java.lang.Object
  java.lang.Thread
      inputOutputHandler.NextMixConnectionHandler

All Implemented Interfaces:

java.lang.Runnable

final class NextMixConnectionHandler
extends java.lang.Thread

Handles communication with the next mix in the cascade.

Establishes a (TCP) connection with the next mix which is used to transmit messages (Requests and Replyies) of all users connected to the cascade's fist mix (multiplex channel).

(De-)multiplexes Requests/Replyies using an (encrypted) header (see generateInterMixHeader()).

Replyies are put in the InputOutputHandlerController's replyInputQueue (see InputOutputHandlerController.addUnprocessedReply()). Requests are taken from the InputOutputHandlerController's requestOutputQueue (see InputOutputHandlerController.getProcessedRequest()).

Note: Authentication is NOT implemented!

Author:

Karl-Peter Fuchs

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

java.lang.Thread.State, java.lang.Thread.UncaughtExceptionHandler

Field Summary

private ExternalInformationPortController	externalInformationPort Reference on component ExternalInformationPort (Used to provide the cryptographic key used to encrypt/decrypt multiplex-headers to the previous mix.
private java.util.concurrent.atomic.AtomicBoolean	handleRepliesIsWaitingForConnection Indicates that method handleReplies() wants to send replies (to next mix), but the connection is lost (Used for synchronization, when reestablishing connection).
private InputOutputHandlerController	inputOutputHandler Reference on InputOutputHandlerController() (Used to get processed replies and add unprocessed requests).
private int	INTER_MIX_BLOCK_SIZE Block size of the cryptographic algorithm used to encrypt the multiplex-header.
private javax.crypto.Cipher	interMixDecryptCipherWithNextMix Cipher for decrypting multiplex-headers of replies.
private javax.crypto.Cipher	interMixEncryptCipherWithNextMix Cipher for encrypting multiplex-headers of requests.
private javax.crypto.spec.IvParameterSpec	interMixIVWithNextMix Initialization vector used to encrypt data between this mix and the next one.
private javax.crypto.SecretKey	interMixKeyWithNextMix Key used to encrypt data between this mix and the next one.
private static InternalInformationPortController	internalInformationPort Reference on component InternalInformationPort.
private static java.util.logging.Logger	LOGGER Logger used to log and display information.
private java.net.InetAddress	NEXT_MIX_ADDRESS Address of the next mix (in the cascade).
private int	NEXT_MIX_INFO_PORT Port number of the next mix' ExternalInformationProvider component (used to receive key for enrypting/decrypting multiplex-headers).
private int	NEXT_MIX_PORT Port number of the next mix (in the cascade).
private java.io.InputStream	nextMixInputStream InputStream for communicating with next mix.
private java.io.OutputStream	nextMixOutputStream OutputStream for communicating with next mix.
private java.net.Socket	nextMixSocket Socket for communicating with next mix.
private int	POSITION_OF_MIX_IN_CASCADE The mix' position in the cascade this object belongs to. "1" means "first mix", "2" means "a middle mix" and "3" means "last mix" of cascade.
private UserDatabaseController	userDatabase Reference on component UserDatabase (Used to add/remove users).

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

protected

NextMixConnectionHandler(InputOutputHandlerController inputOutputHandler, UserDatabaseController userDatabase, ExternalInformationPortController externalInformationPort) Constructs a new NextMixConnectionHandler which handles communication with the next mix in the cascade.

Method Summary

private void	connectToNextMix() Establishes a (permanent) connection to the next mix of the cascade.
private byte[]	encryptInterMixHeader(byte[] message) Encrypts the block containing the multiplex-header of the bypassed message.
private byte[]	generateInterMixHeader(Request request) Adds an (encrypted) header to a Request containing an identifier for the suiting channel (the identifier is unique for any neighboured mixes).
private byte[]	getPayload(Request request) Returns the payload of the bypassed Request.
private static java.lang.String	getProperty(java.lang.String key) Simply used to shorten method calls (calls internalInformationPort.getProperty(key)).
private void	handleReplies() Waits for Replyies sent by next mix.
private void	resetInterMixCiphers() Resets the Ciphers used to encrypt data between this mix and the next one.
void	run() Sends processed messages (Requests) to next mix.
private void	setUpInterMixCiphers() Receives a cryptographic key, that is used to encrypt multiplex-headers (between this mix an the next mix) from the next mix and sets up suiting Ciphers.
private void	waitForConnection() Waits until a connection to the next mix is (re)established.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

internalInformationPort

private static InternalInformationPortController internalInformationPort

Reference on component InternalInformationPort. Used to display and/or log data and read general settings.

LOGGER

private static final java.util.logging.Logger LOGGER

Logger used to log and display information.

POSITION_OF_MIX_IN_CASCADE

private final int POSITION_OF_MIX_IN_CASCADE

The mix' position in the cascade this object belongs to. "1" means "first mix", "2" means "a middle mix" and "3" means "last mix" of cascade.

INTER_MIX_BLOCK_SIZE

private final int INTER_MIX_BLOCK_SIZE

Block size of the cryptographic algorithm used to encrypt the multiplex-header.

NEXT_MIX_ADDRESS

private final java.net.InetAddress NEXT_MIX_ADDRESS

Address of the next mix (in the cascade).

NEXT_MIX_PORT

private final int NEXT_MIX_PORT

Port number of the next mix (in the cascade).

NEXT_MIX_INFO_PORT

private final int NEXT_MIX_INFO_PORT

Port number of the next mix' ExternalInformationProvider component (used to receive key for enrypting/decrypting multiplex-headers).

userDatabase

private UserDatabaseController userDatabase

Reference on component UserDatabase (Used to add/remove users).

inputOutputHandler

private InputOutputHandlerController inputOutputHandler

Reference on InputOutputHandlerController() (Used to get processed replies and add unprocessed requests).

See Also:

InputOutputHandlerController.addUnprocessedRequest(Request), InputOutputHandlerController.getProcessedReply()

externalInformationPort

private ExternalInformationPortController externalInformationPort

Reference on component ExternalInformationPort (Used to provide the cryptographic key used to encrypt/decrypt multiplex-headers to the previous mix.

nextMixSocket

private java.net.Socket nextMixSocket

Socket for communicating with next mix.

nextMixInputStream

private java.io.InputStream nextMixInputStream

InputStream for communicating with next mix.

nextMixOutputStream

private java.io.OutputStream nextMixOutputStream

OutputStream for communicating with next mix.

interMixEncryptCipherWithNextMix

private javax.crypto.Cipher interMixEncryptCipherWithNextMix

Cipher for encrypting multiplex-headers of requests.

interMixDecryptCipherWithNextMix

private javax.crypto.Cipher interMixDecryptCipherWithNextMix

Cipher for decrypting multiplex-headers of replies.

interMixKeyWithNextMix

private javax.crypto.SecretKey interMixKeyWithNextMix

Key used to encrypt data between this mix and the next one.

interMixIVWithNextMix

private javax.crypto.spec.IvParameterSpec interMixIVWithNextMix

Initialization vector used to encrypt data between this mix and the next one.

handleRepliesIsWaitingForConnection

private java.util.concurrent.atomic.AtomicBoolean handleRepliesIsWaitingForConnection

Indicates that method handleReplies() wants to send replies (to next mix), but the connection is lost (Used for synchronization, when reestablishing connection).

See Also:

handleReplies(), connectToNextMix()

Constructor Detail

NextMixConnectionHandler

protected NextMixConnectionHandler(InputOutputHandlerController inputOutputHandler,
                                   UserDatabaseController userDatabase,
                                   ExternalInformationPortController externalInformationPort)

Constructs a new NextMixConnectionHandler which handles communication with the next mix in the cascade.

Establishes a (TCP) connection with the next mix which is used to transmit messages (Requests and Replyies) of all users connected to the cascade's fist mix (multiplex channel).

(De-)multiplexes Requests/Replyies using an (encrypted) header (see generateInterMixHeader()).

Replyies are put in the InputOutputHandlerController's replyInputQueue (see InputOutputHandlerController.addUnprocessedReply()). Requests are taken from the InputOutputHandlerController's requestOutputQueue (see InputOutputHandlerController.getProcessedRequest()).

Note: Authentication is NOT implemented!

Method Detail

handleReplies

private void handleReplies()

Waits for Replyies sent by next mix.

waitForConnection

private void waitForConnection()

Waits until a connection to the next mix is (re)established.

run

public void run()

Sends processed messages (Requests) to next mix.

Specified by:

run in interface java.lang.Runnable

Overrides:

run in class java.lang.Thread

See Also:

InputOutputHandlerController.getProcessedRequest()

connectToNextMix

private void connectToNextMix()

Establishes a (permanent) connection to the next mix of the cascade.

generateInterMixHeader

private byte[] generateInterMixHeader(Request request)

Adds an (encrypted) header to a Request containing an identifier for the suiting channel (the identifier is unique for any neighboured mixes).

Parameters:

request - Request without header.

Returns:

Request with header.

getPayload

private byte[] getPayload(Request request)

Returns the payload of the bypassed Request.

Parameters:

request - Request containing the payload to be returned.

Returns:

Payload of the bypassed Request.

encryptInterMixHeader

private byte[] encryptInterMixHeader(byte[] message)

Encrypts the block containing the multiplex-header of the bypassed message.

Parameters:

message - Message with plaintext multiplex-header.

Returns:

Message with encrypted multiplex-header.

setUpInterMixCiphers

private void setUpInterMixCiphers()

Receives a cryptographic key, that is used to encrypt multiplex-headers (between this mix an the next mix) from the next mix and sets up suiting Ciphers.

Note: Authentication NOT implemented!

resetInterMixCiphers

private void resetInterMixCiphers()

Resets the Ciphers used to encrypt data between this mix and the next one. Must be called when connection was lost, since Ciphers might be out of sync in that case.

getProperty

private static java.lang.String getProperty(java.lang.String key)

Simply used to shorten method calls (calls internalInformationPort.getProperty(key)). Returns the property with the specified key from the property file.

Parameters:

key - The property key.

Returns:

The property with the specified key in the property file.