Package net.i2p.router.tunnel

Class TrivialPreprocessor

java.lang.Object

net.i2p.router.tunnel.TrivialPreprocessor

All Implemented Interfaces:

TunnelGateway.QueuePreprocessor

Direct Known Subclasses:

BatchedPreprocessor, TrivialRouterPreprocessor

class TrivialPreprocessor
extends Object
implements TunnelGateway.QueuePreprocessor

Do the simplest thing possible for preprocessing - for each message available, turn it into the minimum number of fragmented preprocessed blocks, sending each of those out. This does not coallesce message fragments or delay for more optimal throughput. See FragmentHandler Javadoc for tunnel message fragment format Not instantiated directly except in unit tests; see BatchedPreprocessor

Field Summary

Fields

Modifier and Type	Field	Description
protected final RouterContext	_context
protected static final ByteCache	_dataCache	Here in tunnels, we take from the cache but never add to it.
protected final Log	_log
protected static final int	IV_SIZE
static final int	PREPROCESSED_SIZE

Constructor Summary

Constructors

Constructor	Description
TrivialPreprocessor(RouterContext ctx)

Method Summary

Modifier and Type	Method	Description
long	getDelayAmount()	how long do we want to wait before flushing
protected static int	getInstructionAugmentationSize(PendingGatewayMessage msg, int offset, int instructionsSize)
protected static int	getInstructionsSize(PendingGatewayMessage msg)
protected void	notePreprocessing(long messageId, int numFragments, int totalLength, List<Long> messageIds, String msg)
protected void	preprocess(byte[] fragments, int fragmentLength)	Wrap the preprocessed fragments with the necessary padding / checksums to act as a tunnel message.
boolean	preprocessQueue(List<PendingGatewayMessage> pending, TunnelGateway.Sender sender, TunnelGateway.Receiver rec)	Return true if there were messages remaining, and we should queue up a delayed flush to clear them NOTE: Unused here, see BatchedPreprocessor override, super is not called.
protected int	writeFirstFragment(PendingGatewayMessage msg, byte[] target, int offset)
protected int	writeSubsequentFragment(PendingGatewayMessage msg, byte[] target, int offset)

Methods inherited from class java.lang.Object

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

Field Details

_context

protected final RouterContext _context

_log

protected final Log _log

PREPROCESSED_SIZE

public static final int PREPROCESSED_SIZE

See Also:

• Constant Field Values

IV_SIZE

protected static final int IV_SIZE

See Also:

• Constant Field Values

_dataCache

protected static final ByteCache _dataCache

Here in tunnels, we take from the cache but never add to it. In other words, we take advantage of other places in the router also using 1024-byte ByteCaches (since ByteCache only maintains once instance for each size) Used in BatchedPreprocessor; see add'l comments there

Constructor Details

TrivialPreprocessor

public TrivialPreprocessor(RouterContext ctx)

Method Details

getDelayAmount

public long getDelayAmount()

how long do we want to wait before flushing

Specified by:

getDelayAmount in interface TunnelGateway.QueuePreprocessor

preprocessQueue

public boolean preprocessQueue(List<PendingGatewayMessage> pending,
 TunnelGateway.Sender sender,
 TunnelGateway.Receiver rec)

Return true if there were messages remaining, and we should queue up a delayed flush to clear them NOTE: Unused here, see BatchedPreprocessor override, super is not called.

Specified by:

preprocessQueue in interface TunnelGateway.QueuePreprocessor

Parameters:

pending - list of Pending objects for messages either unsent or partly sent. This list should be update with any values removed (the preprocessor owns the lock) Messages are not removed from the list until actually sent. The status of unsent and partially-sent messages is stored in the Pending structure.

Returns:

true if we should delay before preprocessing again

notePreprocessing

protected void notePreprocessing(long messageId,
 int numFragments,
 int totalLength,
 List<Long> messageIds,
 String msg)

preprocess

protected void preprocess(byte[] fragments,
 int fragmentLength)

Wrap the preprocessed fragments with the necessary padding / checksums to act as a tunnel message.

Parameters:

fragmentLength - fragments[0:fragmentLength] is used

writeFirstFragment

protected int writeFirstFragment(PendingGatewayMessage msg,
 byte[] target,
 int offset)

writeSubsequentFragment

protected int writeSubsequentFragment(PendingGatewayMessage msg,
 byte[] target,
 int offset)

getInstructionsSize

protected static int getInstructionsSize(PendingGatewayMessage msg)

Returns:

generally 3 or 35 or 39 for first fragment, 7 for subsequent fragments. Does NOT include 4 for the message ID if the message will be fragmented; call getInstructionAugmentationSize() for that.

getInstructionAugmentationSize

protected static int getInstructionAugmentationSize(PendingGatewayMessage msg,
 int offset,
 int instructionsSize)

Returns:

0 or 4