Crate tari_comms_dht 

Tari Comms DHT

Overview

The tari_comms_dht crate adds DHT functionality to tari_comms. It provides two sets of middleware (inbound and outbound) which process incoming requests and outgoing messages respectively.

Attaching to comms

In tari_comms, incoming and outgoing messages are connected using two mpsc sender/receiver pairs. One for incoming messages (receiving InboundMessages) and one for outbound messages (sending OutboundMessages).

The DHT module consists of two middleware layers (as in tower_layer::Layer) which form an inbound and outbound pipeline for augmenting messages.

Inbound Message Flow

InboundMessages are received from the incoming comms channel (as in the receiver side of of the mpsc channel which goes into CommsBuilder::new().incoming_message_sink(sender)). Typically, a ServicePipeline from the tari_comms::middleware crate is used to connect a stream from comms to the middleware service.

InboundMessage(comms) -> DHT Inbound Middleware -> DhtInboundMessage(domain)

The DHT inbound middleware consist of:

• metrics: monitors the number of inbound messages
• decryption: deserializes and decrypts the InboundMessage and produces a DecryptedDhtMessage.
• dedup: discards the message if previously received.
• logging: message logging
• DHT message handler: handles DHT protocol messages (discovery, join etc.)

Outbound Message Flow

OutboundMessages are sent to the outgoing comms channel (as in the receiver side of of the mpsc channel which goes into CommsBuilder::new().outgoing_message_stream(receiver)). Typically, a ServicePipeline from the tari_comms::middleware crate is used to connect a stream from the domain-level to the middleware service and a SinkMiddleware to connect the middleware to the OMS in comms. Outbound requests to the DHT middleware are furnished by the OutboundMessageRequester, obtained from the Dht::outbound_requester factory method.

DhtOutboundRequest (domain) -> DHT Outbound Middleware -> OutboundMessage (comms)

The DHT outbound middleware consist of:

• broadcast layer: produces multiple outbound messages according on the BroadcastStrategy from the received DhtOutboundRequest message. The next_service is called for each resulting message.
• message logger layer.
• serialization: wraps the body in a DhtOutboundMessage, serializes the result, constructs an OutboundMessage and calls next_service. Typically, next_service will be a SinkMiddleware which send the message to comms messaging.

Modules

broadcast_strategy

Broadcast strategy

domain_message

envelope

event

inbound

DHT middleware layers for inbound messages.

outbound

DHT middleware layers for outbound messages.

Structs

DHTCommsHashDomain

A hashing domain instance

DedupLayer

Dht

Responsible for starting the DHT actor, building the DHT middleware stack and as a factory for producing DHT requesters.

DhtBuilder

Builder for the DHT.

DhtConfig

DhtConnectivityConfig

DhtDiscoveryRequester

DhtRequester

DHT actor requester

MetricsCollectorHandle

NetworkDiscoveryConfig

Enums

BootstrapMethod

DhtActorError

Error type for the DHT actor

DhtDiscoveryError

DhtEncryptError

DhtInitializationError

DhtProtocolVersion

Versions for the DHT protocol

DhtRequest

Request type for the DHT actor

DiscoveryPhase

Functions

comms_dht_hash_domain_challenge

Hash domain used to produce binding message hashes

comms_dht_hash_domain_key_mask

Hash domain used for message encryption key masking

comms_dht_hash_domain_key_message

Hash domain used for message encryption keys

comms_dht_hash_domain_message_signature

Hash domain used for message signing