2.7 KiB
discv5
Overview
This is a rust implementation of the Discovery v5 peer discovery protocol.
Discovery v5 is a protocol designed for encrypted peer discovery and topic advertisement. Each peer/node
on the network is identified via it's ENR (Ethereum Node
Record), which is essentially a signed key-value store
containing the node's public key and optionally IP address and port.
Discv5 employs a kademlia-like routing table to store and manage discovered peers and topics. The protocol allows for external IP discovery in NAT environments through regular PING/PONG's with discovered nodes. Nodes return the external IP address that they have received and a simple majority is chosen as our external IP address. If an external IP address is updated, this is produced as an event to notify the swarm (if one is used for this behaviour).
For a simple CLI discovery service see discv5-cli
Usage
A simple example of creating this service is as follows:
use discv5::{enr, enr::{CombinedKey, NodeId}, TokioExecutor, Discv5, Discv5ConfigBuilder};
use std::net::SocketAddr;
// listening address and port
let listen_addr = "0.0.0.0:9000".parse::<SocketAddr>().unwrap();
// construct a local ENR
let enr_key = CombinedKey::generate_secp256k1();
let enr = enr::EnrBuilder::new("v4").build(&enr_key).unwrap();
// build the tokio executor
let mut runtime = tokio::runtime::Builder::new_multi_thread()
.thread_name("Discv5-example")
.enable_all()
.build()
.unwrap();
// default configuration
let config = Discv5ConfigBuilder::new().build();
// construct the discv5 server
let mut discv5 = Discv5::new(enr, enr_key, config).unwrap();
// In order to bootstrap the routing table an external ENR should be added
// This can be done via add_enr. I.e.:
// discv5.add_enr(<ENR>)
// start the discv5 server
runtime.block_on(discv5.start(listen_addr));
// run a find_node query
runtime.block_on(async {
let found_nodes = discv5.find_node(NodeId::random()).await.unwrap();
println!("Found nodes: {:?}", found_nodes);
});