java.lang.Object
net.i2p.router.tunnel.HopProcessor
Direct Known Subclasses:
InboundGatewayProcessor
class HopProcessorextends 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
    Description
    protected final HopConfig
    _config
    Config for this hop, holding the IV and layer keys and the expected previous hop.
    protected final I2PAppContext
    _context
    Router or client context, supplying the log and the AES engine.
    (package private) static final int
    IV_LENGTH
    Length in bytes of the per-hop IV preceding the message data (16).

  • Constructor Summary

    Constructors
    Constructor
    Description
    HopProcessor(I2PAppContext ctx, HopConfig config, IVValidator validator)
    Create a processor for a single hop of a tunnel.

  • Method Summary

    All Methods
    Modifier and Type
    Method
    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()
    Processor summary for log messages.

    Methods inherited from class Object

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

  • Field Details

    • _context

      protected final I2PAppContext _context
      Router or client context, supplying the log and the AES engine.

    • _config

      protected final HopConfig _config
      Config for this hop, holding the IV and layer keys and the expected previous hop.

    • IV_LENGTH

      static final int IV_LENGTH
      Length in bytes of the per-hop IV preceding the message data (16). The tunnel crypto encrypts 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:

  • Constructor Details

    • HopProcessor

      public HopProcessor(I2PAppContext ctx, HopConfig config, IVValidator validator)
      Create a processor for a single hop of a tunnel.
      Parameters:
      ctx - the router or client context
      config - this hop's tunnel config
      validator - checks that the message IV is one we have not seen

  • Method Details

    • 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()
      Processor summary for log messages.
      Overrides:
      toString in class Object