vsock-proxy 0.1.2

A minimal CLI to proxy TCP traffic to or from VSock
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use clap::{Arg, Command};

mod net;

use net::{Address, Error, Listener};

fn main() {
    let matches = Command::new("vsock-proxy")
        .about("A simple proxy to pipe traffic to/from a vsock connection")
        .arg(
            Arg::new("tcp-source")
                .long("tcp-source")
                .help("The tcp address for the proxy to listen on.")
                .conflicts_with("vsock-source")
                .required(false),
        )
        .arg(
            Arg::new("tcp-destination")
                .long("tcp-dest")
                .help("The tcp address for the proxy to forward to.")
                .conflicts_with("vsock-destination")
                .conflicts_with("tcp-source")
                .required(false),
        )
        .arg(
            Arg::new("vsock-source")
                .long("vsock-source")
                .help("The vsock address for the proxy to listen on.")
                .required(false),
        )
        .arg(
            Arg::new("vsock-destination")
                .long("vsock-dest")
                .help("The vsock address for the proxy to forward to.")
                .conflicts_with("vsock-source")
                .required(false),
        )
        .get_matches();

    let tcp_source = matches.get_one::<String>("tcp-source");
    let vsock_source = matches.get_one::<String>("vsock-source");

    if tcp_source.is_none() && vsock_source.is_none() {
        eprintln!("Error: no source address provided. Either tcp-source or vsock-source must be provided.");
        return;
    }

    let tcp_destination = matches.get_one::<String>("tcp-destination");
    let vsock_destination = matches.get_one::<String>("vsock-destination");

    if tcp_destination.is_none() && vsock_destination.is_none() {
        eprintln!("Error: no destination address provided. Either tcp-destination or vsock-destination must be provided.");
        return;
    }

    let parsed_source_address: Result<Address, Error> = tcp_source
        .map(|tcp_addr| Address::new_tcp_address(tcp_addr.as_str()))
        .or_else(|| vsock_source.map(|vsock_addr| Address::new_vsock_address(vsock_addr.as_str())))
        .expect("Infallible: either tcp or vsock source address must exist.");

    let source_address = match parsed_source_address {
        Ok(source_addr) => source_addr,
        Err(e) => {
            eprintln!("Error: {e}");
            return;
        }
    };

    let parsed_destination: Result<Address, Error> = tcp_destination
        .map(|tcp_addr| Address::new_tcp_address(tcp_addr))
        .or_else(|| vsock_destination.map(|vsock_addr| Address::new_vsock_address(vsock_addr)))
        .expect("Infallible: either tcp or vsock address must exist");

    let destination_address = match parsed_destination {
        Ok(dest_addr) => dest_addr,
        Err(e) => {
            eprintln!("Error: {e}");
            return;
        }
    };

    let runtime = tokio::runtime::Builder::new_current_thread()
        .enable_io()
        .build()
        .expect("Failed to build tokio runtime");

    runtime.block_on(async move {
        let mut source = match source_address.into_listener().await {
            Ok(source_conn) => source_conn,
            Err(e) => {
                eprintln!("Failed to create source connection - {e}");
                return;
            }
        };

        loop {
            let mut accepted_conn = match source.accept().await {
                Ok(source_conn) => source_conn,
                Err(e) => {
                    eprintln!("Failed to accept incoming connection - {e}");
                    continue;
                }
            };

            let mut destination = match destination_address.get_destination_connection().await {
                Ok(dest_conn) => dest_conn,
                Err(e) => {
                    eprintln!("Failed to create destination connection - {e}");
                    continue;
                }
            };

            if let Err(e) =
                tokio::io::copy_bidirectional(&mut accepted_conn, &mut destination).await
            {
                eprintln!("Error piping connections - {e}");
            }
        }
    });
}