com.subgraph.orchid.circuits

Class CircuitNodeImpl

java.lang.Object

com.subgraph.orchid.circuits.CircuitNodeImpl

All Implemented Interfaces:

CircuitNode

public class CircuitNodeImpl
extends Object
implements CircuitNode

Method Summary

Modifier and Type	Method and Description
boolean	considerSendingSendme() Examines the delivery window and determines if it would be an appropriate time to send a RELAY_SENDME cell.
static CircuitNode	createAnonymous(CircuitNode previous, byte[] keyMaterial, byte[] verifyDigest)
static CircuitNode	createFirstHop(Router r, byte[] keyMaterial, byte[] verifyDigest)
static CircuitNode	createNode(Router r, CircuitNode previous, byte[] keyMaterial, byte[] verifyDigest)
void	decrementDeliverWindow() This method is called when a RELAY_DATA cell is received from this node to decrement the deliver window counter.
boolean	decryptBackwardCell(Cell cell)
void	encryptForwardCell(RelayCell cell) Encrypt a RelayCell for this node with the current 'forward' cipher state.
byte[]	getForwardDigestBytes() Return the current 'forward' running digest value for this node as an array of TOR_DIGEST_SIZE bytes.
CircuitNode	getPreviousNode() Return the CircuitNode which immediately preceeds this one in the circuit node chain or null if this is the first hop.
Router	getRouter() Return the Router associated with this node.
void	incrementSendWindow() This method is called to signal that a RELAY_SENDME cell has been received from this node and the packaging window should be incremented.
String	toString()
void	updateForwardDigest(RelayCell cell) Update the 'forward' cryptographic digest state for this node with the contents of cell
void	waitForSendWindow() Return immediately if the packaging window for this node is open (ie: greater than 0), otherwise block until the circuit is destroyed or the window is incremented by receiving a RELAY_SENDME cell from this node.
void	waitForSendWindowAndDecrement() If the packaging window for this node is open (ie: greater than 0) this method decrements the packaging window by 1 and returns immediately, otherwise it will block until the circuit is destroyed or the window is incremented by receiving a RELAY_SENDME cell from this node.

Methods inherited from class java.lang.Object

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

Method Detail

createAnonymous

public static CircuitNode createAnonymous(CircuitNode previous,
                                          byte[] keyMaterial,
                                          byte[] verifyDigest)

createFirstHop

public static CircuitNode createFirstHop(Router r,
                                         byte[] keyMaterial,
                                         byte[] verifyDigest)

createNode

public static CircuitNode createNode(Router r,
                                     CircuitNode previous,
                                     byte[] keyMaterial,
                                     byte[] verifyDigest)

getRouter

public Router getRouter()

Description copied from interface: CircuitNode

Return the Router associated with this node.

Specified by:

getRouter in interface CircuitNode

Returns:

The Router for this hop of the circuit chain.

getPreviousNode

public CircuitNode getPreviousNode()

Description copied from interface: CircuitNode

Return the CircuitNode which immediately preceeds this one in the circuit node chain or null if this is the first hop.

Specified by:

getPreviousNode in interface CircuitNode

Returns:

The previous CircuitNode in the chain or null if this is the first node.

encryptForwardCell

public void encryptForwardCell(RelayCell cell)

Description copied from interface: CircuitNode

Encrypt a RelayCell for this node with the current 'forward' cipher state.

Specified by:

encryptForwardCell in interface CircuitNode

Parameters:

cell - The RelayCell to encrypt.

decryptBackwardCell

public boolean decryptBackwardCell(Cell cell)

Specified by:

decryptBackwardCell in interface CircuitNode

updateForwardDigest

public void updateForwardDigest(RelayCell cell)

Description copied from interface: CircuitNode

Update the 'forward' cryptographic digest state for this node with the contents of cell

Specified by:

updateForwardDigest in interface CircuitNode

Parameters:

cell - The RelayCell to add to the digest.

getForwardDigestBytes

public byte[] getForwardDigestBytes()

Description copied from interface: CircuitNode

Return the current 'forward' running digest value for this node as an array of TOR_DIGEST_SIZE bytes.

Specified by:

getForwardDigestBytes in interface CircuitNode

Returns:

The current 'forward' running digest value for this node.

toString

public String toString()

Overrides:

toString in class Object

decrementDeliverWindow

public void decrementDeliverWindow()

Description copied from interface: CircuitNode

This method is called when a RELAY_DATA cell is received from this node to decrement the deliver window counter.

Specified by:

decrementDeliverWindow in interface CircuitNode

considerSendingSendme

public boolean considerSendingSendme()

Description copied from interface: CircuitNode

Examines the delivery window and determines if it would be an appropriate time to send a RELAY_SENDME cell. If this method returns true, it increments the delivery window assuming that a RELAY_SENDME cell will be transmitted.

Specified by:

considerSendingSendme in interface CircuitNode

Returns:

Returns true if the deliver window is small enough that sending a RELAY_SENDME cell would be appropriate.

waitForSendWindow

public void waitForSendWindow()

Description copied from interface: CircuitNode

Return immediately if the packaging window for this node is open (ie: greater than 0), otherwise block until the circuit is destroyed or the window is incremented by receiving a RELAY_SENDME cell from this node.

Specified by:

waitForSendWindow in interface CircuitNode

waitForSendWindowAndDecrement

public void waitForSendWindowAndDecrement()

Description copied from interface: CircuitNode

If the packaging window for this node is open (ie: greater than 0) this method decrements the packaging window by 1 and returns immediately, otherwise it will block until the circuit is destroyed or the window is incremented by receiving a RELAY_SENDME cell from this node. This method will always decrement the packaging window before returning unless the circuit has been destroyed.

Specified by:

waitForSendWindowAndDecrement in interface CircuitNode

incrementSendWindow

public void incrementSendWindow()

Description copied from interface: CircuitNode

This method is called to signal that a RELAY_SENDME cell has been received from this node and the packaging window should be incremented. This will also wake up any threads that are waiting for the packaging window to open.

Specified by:

incrementSendWindow in interface CircuitNode