Package net.i2p.router.transport.udp

The UDP transport (also known as 'SSU' or Secure Semi-reliable UDP transport) for I2P, allowing I2P messages to be passed over UDP connections.

See: Description

Interface Summary

Interface	Description
ACKBitfield	Generic means of SACK/NACK transmission for partially or fully received messages
SocketListener	Listener for socket events.
SSU2Bitfield.Callback	Callback interface for bitfield operations.
SSU2Payload.PayloadCallback	For all callbacks, recommend throwing exceptions only from the handshake.
SSU2Sender	Basic interface over top of PeerState2 and PeerStateDestroyed, so we can pass them both to PacketBuilder2 to send packets.

Class Summary

Class	Description
EstablishmentManager	Coordinate the establishment of new sessions - both inbound and outbound.
EstablishmentManager.Token	Token used for SSU2 session establishment and validation.
InboundEstablishState	Data for a new connection being established, where the remote peer has initiated the connection with us.
InboundEstablishState2	Data for a new connection being established, where the remote peer has initiated the connection with us.
InboundMessageFragments	Organize the received data message fragments, feeding completed messages to the MessageReceiver and telling the PeerState to ACK.
InboundMessageFragments.ModifiableLong	Modifiable Long, no locking
InboundMessageState	Hold the raw data fragments of an inbound message.
IntroductionManager	Keep track of inbound and outbound introductions.
IPThrottler	Throttles connection attempts by IP address to prevent abuse.
MessageReceiver	Pull fully completed fragments off the InboundMessageFragments queue, parse 'em into I2NPMessages, and stick them on the InNetMessagePool by way of the UDPTransport.
MTU	Get the MTU for the network interface of an address.
OutboundEstablishState	Data for a new connection being established, where we initiated the connection with a remote peer.
OutboundEstablishState2	Data for a new connection being established, where we initiated the connection with a remote peer.
OutboundMessageFragments	Coordinate the outbound fragments and select the next one to be built.
OutboundMessageState	Maintain the outbound fragmentation for resending, for a single message.
PacketBuilder	Builder for UDP packets.
PacketBuilder.Fragment	Class for passing multiple fragments to buildPacket()
PacketBuilder2	Builds and encrypts SSU2 protocol packets for UDP transport.
PacketHandler	Pull inbound packets from the inbound receiver's queue, figure out what peer session they belong to (if any), authenticate and decrypt them with the appropriate keys, and push them to the appropriate handler.
PacketPusher	Blocking thread to grab new packets off the outbound fragment pool and toss them onto the outbound packet queues.
PeerState	Contain all of the state about a UDP connection to a peer.
PeerState2	Contain all of the state about a UDP connection to a peer.
PeerStateDestroyed	Small, stub version of PeerState2, for handling destroy acks with possible tokens in them.
PeerTestEvent	Initiate a test (we are Alice)
PeerTestManager	Entry points are runTest() to start a new test as Alice, and receiveTest() for all received test packets.
PeerTestState	Track the state of a peer test.
RemoteHostId	Unique ID for a peer - its IP + port, all bundled into a tidy obj.
SimpleBandwidthEstimator	A Westwood+ bandwidth estimator with: <ul> <li>A first-stage anti-aliasing low-pass filter based on RTT</li> <li>A time-varying EWMA filter based on inter-arrival time</li> </ul> <p>This estimator is adapted from the Linux kernel's <code>tcp_westwood.c</code> implementation and the Westwood+ research paper.</p> <p>Ref: <em>TCP Westwood: End-to-End Congestion Control for Wired/Wireless Networks</em> - Casetti et al.</p> <p>Ref: <em>End-to-End Bandwidth Estimation for Congestion Control in Packet Networks</em> - Grieco and Mascolo.</p> <p>Adapted for I2P streaming transport in 0.9.49.</p>
SSU2Bitfield	Container of a long array representing set and unset bits.
SSU2Header	Encrypt/decrypt headers
SSU2Header.Header	A temporary structure returned from trial decrypt, with methods to access the fields.
SSU2Payload	SSU2 Payload generation and parsing utilities.
SSU2Payload.AckBlock	Block containing acknowledgment data.
SSU2Payload.AddressBlock	Block containing IP address and port information.
SSU2Payload.Block	Base class for blocks to be transmitted.
SSU2Payload.DateTimeBlock	Block containing the current date and time.
SSU2Payload.FirstFragBlock	Same format as I2NPBlock
SSU2Payload.FollowFragBlock	Follow-on fragment block for SSU2 payload.
SSU2Payload.I2NPBlock	Block containing I2NP message data.
SSU2Payload.NewTokenBlock	Block containing a new session token.
SSU2Payload.OptionsBlock	Block containing session options.
SSU2Payload.PaddingBlock	Block containing padding data.
SSU2Payload.PathChallengeBlock	Path challenge block for SSU2 payload.
SSU2Payload.PathResponseBlock	Path response block for SSU2 payload.
SSU2Payload.PeerTestBlock	Block containing peer test data.
SSU2Payload.RelayIntroBlock	Block containing relay introduction data.
SSU2Payload.RelayRequestBlock	Block containing relay request data.
SSU2Payload.RelayResponseBlock	Block containing relay response data.
SSU2Payload.RelayTagBlock	Block containing relay tag data.
SSU2Payload.RelayTagRequestBlock	Block containing relay tag request data.
SSU2Payload.RIBlock	Block containing router information data.
SSU2Payload.TerminationBlock	Block containing session termination data.
SSU2Util	SSU2 Utils and constants
UDPAddress	UDP address parser and validator for I2P peer information.
UDPEndpoint	Coordinate the low-level datagram socket, creating and managing the UDPSender and UDPReceiver.
UDPPacket	UDP packet wrapper with caching and metadata support.
UDPReceiver	Lowest level component to pull raw UDP datagrams off the wire as fast as possible, controlled by both the bandwidth limiter and the router's throttle.
UDPSender	Lowest level UDP packet sender that pushes packets from its queue ASAP.
UDPTransport	Secure Semi-reliable UDP (SSU) transport implementation for I2P.

Enum Summary

Enum	Description
InboundEstablishState.InboundState	States for inbound SSU session establishment.
OutboundEstablishState.OutboundState	States for outbound SSU session establishment.
OutboundEstablishState2.IntroState	Per-introducer introduction states
PeerTestState.Role	Roles for peer testing scenarios.

Package net.i2p.router.transport.udp Description

The UDP transport (also known as 'SSU' or Secure Semi-reliable UDP transport) for I2P, allowing I2P messages to be passed over UDP connections.

This package provides:

• UDP-based peer connections
• Secure semi-reliable message delivery
• NAT traversal capabilities
• Introduction and rendezvous protocols
• Faster peer discovery compared to TCP

SSU is optimized for firewall and NAT traversal, making it ideal for routers behind restrictive network configurations. It provides improved performance for peer discovery and connectivity in challenging network environments.