modify end server to connect to a local TCP server

Tested with netcat on each end and it works great.

prototypes/quic_demo/README.md

@@ -0,0 +1,14 @@
+# Testing
+
+
+
+There are 5 processes, so you'll need 5 terminal windows or screen / tmux
+sessions:
+
+1. TCP end server: `nc -l -p 30382`
+2. QUIC relay server: `RUST_LOG=quic_demo_relay_server=debug cargo run --bin quic_demo_relay_server`
+3. Server-side adapter: `RUST_LOG=quic_demo_end_server=debug cargo run --bin quic_demo_end_server`
+4. Client-side adapter: `RUST_LOG=quic_demo_client cargo run --bin quic_demo_client`
+5. TCP end client: `nc 127.0.0.1 30381`
+
+The netcat processes from steps 1 and 5 should now be connected to each other.

prototypes/quic_demo/src/bin/quic_demo_client.rs

@@ -29,6 +29,8 @@ async fn main () -> anyhow::Result <()> {
 	
 	let (mut relay_send, mut relay_recv) = connection.open_bi ().await?;
 	
+	debug! ("Relaying bytes...");
+	
 	let uplink_task = tokio::spawn (async move {
 		// Uplink - local client to relay server
 		

prototypes/quic_demo/src/bin/quic_demo_end_server.rs

@@ -1,9 +1,15 @@
+use tokio::net::TcpStream;
+
 use quic_demo::prelude::*;
 
 #[tokio::main]
 async fn main () -> anyhow::Result <()> {
 	tracing_subscriber::fmt::init ();
 	
+	let stream = TcpStream::connect ("127.0.0.1:30382").await?;
+	
+	let (mut local_recv, mut local_send) = stream.into_split ();
+	
 	let server_cert = tokio::fs::read ("quic_server.crt").await?;
 	let server_addr = "127.0.0.1:30380".parse ()?;
 	let endpoint = make_client_endpoint ("0.0.0.0:0".parse ()?, &[&server_cert])?;
@@ -15,15 +21,43 @@ async fn main () -> anyhow::Result <()> {
 		..
 	} = endpoint.connect (&server_addr, "localhost")?.await?;
 	
-	debug! ("Waiting for incoming bi stream");
+	debug! ("Waiting for relay server to forward a bi stream");
 	
-	let (mut send, mut recv) = bi_streams.next ().await.ok_or_else (|| anyhow::anyhow! ("Relay server didn't open a bi stream"))??;
+	let (mut relay_send, mut relay_recv) = bi_streams.next ().await.ok_or_else (|| anyhow::anyhow! ("Relay server didn't open a bi stream"))??;
+	
+	debug! ("Relaying bytes...");
+	
+	let uplink_task = tokio::spawn (async move {
+		// Uplink - local client to relay server
 		
 		let mut buf = vec! [0u8; 65_536];
-	while let Some (bytes_read) = recv.read (&mut buf).await? {
+		loop {
-		let s = format! ("bytes_read: {}", bytes_read);
+			let bytes_read = local_recv.read (&mut buf).await?;
-		send.write_all (s.as_bytes ()).await?;
+			let buf_slice = &buf [0..bytes_read];
+			relay_send.write_all (buf_slice).await?;
 		}
 		
+		debug! ("Uplink closed");
+		
+		Ok::<_, anyhow::Error> (())
+	});
+	
+	let downlink_task = tokio::spawn (async move {
+		// Downlink - Relay server to local client
+		
+		let mut buf = vec! [0u8; 65_536];
+		while let Some (bytes_read) = relay_recv.read (&mut buf).await? {
+			let buf_slice = &buf [0..bytes_read];
+			local_send.write_all (buf_slice).await?;
+		}
+		
+		debug! ("Downlink closed");
+		
+		Ok::<_, anyhow::Error> (())
+	});
+	
+	uplink_task.await??;
+	downlink_task.await??;
+	
 	Ok (())
 }

prototypes/quic_demo/src/prelude.rs

@@ -2,6 +2,7 @@ pub use std::{
 	time::Duration,
 };
 
+pub use anyhow::bail;
 pub use futures_util::StreamExt;
 pub use tokio::{
 	io::{

prototypes/quic_demo/src/quinn_utils.rs

@@ -1,14 +1,16 @@
 // I'm not sure where I got this module from, but it's probably from the
 // quinn examples, so the license should be okay.
 
+use std::{
+	net::SocketAddr,
+	sync::Arc,
+	time::Duration,
+};
+
 use quinn::{
 	Certificate, CertificateChain, ClientConfig, ClientConfigBuilder, Endpoint, Incoming,
 	PrivateKey, ServerConfig, ServerConfigBuilder, TransportConfig,
 };
-use std::{
-	net::SocketAddr,
-	sync::Arc,
-};
 
 /// Constructs a QUIC endpoint configured for use a client only.
 ///
@@ -20,7 +22,12 @@ pub fn make_client_endpoint(
 	bind_addr: SocketAddr,
 	server_certs: &[&[u8]],
 ) -> anyhow::Result<Endpoint> {
-	let client_cfg = configure_client(server_certs)?;
+	let mut client_cfg = configure_client (server_certs)?;
+	let mut transport = quinn::TransportConfig::default ();
+	transport.keep_alive_interval (Some (Duration::from_millis (5_000)));
+	
+	client_cfg.transport = Arc::new (transport);
+	
 	let mut endpoint_builder = Endpoint::builder ();
 	endpoint_builder.default_client_config (client_cfg);
 	let (endpoint, _incoming) = endpoint_builder.bind(&bind_addr)?;