net.i2p.router.tunnel

Class HopProcessor

java.lang.Object

net.i2p.router.tunnel.HopProcessor

Direct Known Subclasses:

InboundGatewayProcessor

class HopProcessor
extends Object

Take a received tunnel message, verify that it isn't a duplicate, and translate it into what the next hop will want. The hop processor works the same on all peers - inbound and outbound participants, outbound endpoints, and inbound gateways (with a small modification per InboundGatewayProcessor).

Field Summary

Fields

Modifier and Type	Field and Description
protected HopConfig	_config
protected I2PAppContext	_context
(package private) static int	IV_LENGTH as of i2p 0.6, the tunnel crypto changed to encrypt the IV both before and after using it at each hop so as to prevent a certain type of replay/confirmation attack.

Constructor Summary

Constructors

Constructor and Description
HopProcessor(I2PAppContext ctx, HopConfig config, IVValidator validator)

Method Summary

Modifier and Type	Method and Description
boolean	process(byte[] orig, int offset, int length, Hash prev) Process the data for the current hop, overwriting the original data with what should be sent to the next peer.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

_config

protected final HopConfig _config

_context

protected final I2PAppContext _context

IV_LENGTH

static final int IV_LENGTH

as of i2p 0.6, the tunnel crypto changed to encrypt the IV both before and after using it at each hop so as to prevent a certain type of replay/confirmation attack. See: http://osdir.com/ml/network.i2p/2005-07/msg00031.html

See Also:

Constant Field Values

Constructor Detail

HopProcessor

public HopProcessor(I2PAppContext ctx,
                    HopConfig config,
                    IVValidator validator)

Method Detail

process

public boolean process(byte[] orig,
                       int offset,
                       int length,
                       Hash prev)

Process the data for the current hop, overwriting the original data with what should be sent to the next peer. This also validates the previous peer and the IV, making sure its not a repeat and not a loop.

Parameters:

orig - IV+data of the message

offset - index into orig where the IV begins

length - how long after the offset does the IV+message go for? Should always be 1024 bytes.

prev - previous hop in the tunnel, or null if we are the gateway

Returns:

true if the message was updated and valid, false if it was not.

toString

public String toString()

Overrides:

toString in class Object