bore/src/shared.rs

103 lines
3.2 KiB
Rust

//! Shared data structures, utilities, and protocol definitions.
use std::time::Duration;
use anyhow::{Context, Result};
use serde::de::DeserializeOwned;
use serde::{Deserialize, Serialize};
use tokio::io::{self, AsyncBufRead, AsyncBufReadExt, AsyncRead, AsyncWrite, AsyncWriteExt};
use tokio::time::timeout;
use tracing::trace;
use uuid::Uuid;
/// TCP port used for control connections with the server.
pub const CONTROL_PORT: u16 = 7835;
/// Timeout for network connections and initial protocol messages.
pub const NETWORK_TIMEOUT: Duration = Duration::from_secs(3);
/// A message from the client on the control connection.
#[derive(Debug, Serialize, Deserialize)]
pub enum ClientMessage {
/// Response to an authentication challenge from the server.
Authenticate(String),
/// Initial client message specifying a port to forward.
Hello(u16),
/// Accepts an incoming TCP connection, using this stream as a proxy.
Accept(Uuid),
}
/// A message from the server on the control connection.
#[derive(Debug, Serialize, Deserialize)]
pub enum ServerMessage {
/// Authentication challenge, sent as the first message, if enabled.
Challenge(Uuid),
/// Response to a client's initial message, with actual public port.
Hello(u16),
/// No-op used to test if the client is still reachable.
Heartbeat,
/// Asks the client to accept a forwarded TCP connection.
Connection(Uuid),
/// Indicates a server error that terminates the connection.
Error(String),
}
/// Copy data mutually between two read/write streams.
pub async fn proxy<S1, S2>(stream1: S1, stream2: S2) -> io::Result<()>
where
S1: AsyncRead + AsyncWrite + Unpin,
S2: AsyncRead + AsyncWrite + Unpin,
{
let (mut s1_read, mut s1_write) = io::split(stream1);
let (mut s2_read, mut s2_write) = io::split(stream2);
tokio::select! {
res = io::copy(&mut s1_read, &mut s2_write) => res,
res = io::copy(&mut s2_read, &mut s1_write) => res,
}?;
Ok(())
}
/// Read the next null-delimited JSON instruction from a stream.
pub async fn recv_json<T: DeserializeOwned>(
reader: &mut (impl AsyncBufRead + Unpin),
buf: &mut Vec<u8>,
) -> Result<Option<T>> {
trace!("waiting to receive json message");
buf.clear();
reader.read_until(0, buf).await?;
if buf.is_empty() {
return Ok(None);
}
if buf.last() == Some(&0) {
buf.pop();
}
Ok(serde_json::from_slice(buf).context("failed to parse JSON")?)
}
/// Read the next null-delimited JSON instruction, with a default timeout.
///
/// This is useful for parsing the initial message of a stream for handshake or
/// other protocol purposes, where we do not want to wait indefinitely.
pub async fn recv_json_timeout<T: DeserializeOwned>(
reader: &mut (impl AsyncBufRead + Unpin),
) -> Result<Option<T>> {
timeout(NETWORK_TIMEOUT, recv_json(reader, &mut Vec::new()))
.await
.context("timed out waiting for initial message")?
}
/// Send a null-terminated JSON instruction on a stream.
pub async fn send_json<T: Serialize>(writer: &mut (impl AsyncWrite + Unpin), msg: T) -> Result<()> {
trace!("sending json message");
let msg = serde_json::to_vec(&msg)?;
writer.write_all(&msg).await?;
writer.write_all(&[0]).await?;
Ok(())
}