com.subgraph.orchid

Interface CircuitNode

All Known Implementing Classes:

CircuitNodeImpl

public interface CircuitNode

Represents the state of a single onion router hop in a connected or connecting Circuit

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.
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.
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.

Method Detail

getRouter

Router getRouter()

Return the Router associated with this node.

Returns:

The Router for this hop of the circuit chain.

updateForwardDigest

void updateForwardDigest(RelayCell cell)

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

Parameters:

cell - The RelayCell to add to the digest.

getForwardDigestBytes

byte[] getForwardDigestBytes()

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

Returns:

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

encryptForwardCell

void encryptForwardCell(RelayCell cell)

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

Parameters:

cell - The RelayCell to encrypt.

getPreviousNode

CircuitNode getPreviousNode()

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

Returns:

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

waitForSendWindow

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.

waitForSendWindowAndDecrement

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. This method will always decrement the packaging window before returning unless the circuit has been destroyed.

incrementSendWindow

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. This will also wake up any threads that are waiting for the packaging window to open.

decrementDeliverWindow

void decrementDeliverWindow()

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

considerSendingSendme

boolean considerSendingSendme()

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.

Returns:

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

decryptBackwardCell

boolean decryptBackwardCell(Cell cell)