rust-libp2p/libp2p-tcp-transport/src/lib.rs

extern crate libp2p_transport as transport;
extern crate tokio_core;
extern crate tokio_io;
extern crate multiaddr;
extern crate futures;

use std::io::Error as IoError;
use std::net::{IpAddr, Ipv4Addr, SocketAddr};
use tokio_core::reactor::Handle;
use tokio_core::net::{TcpStream, TcpListener};
use futures::Future;
use futures::stream::Stream;
use multiaddr::{Multiaddr, Protocol};
use transport::Transport;

pub struct TCP;

impl Transport for TCP {
    /// The raw connection.
    type RawConn = TcpStream;

    /// The listener produces incoming connections.
    type Listener = Box<Stream<Item=Self::RawConn, Error=IoError>>;

    /// A future which indicates currently dialing to a peer.
    type Dial = Box<Future<Item=Self::RawConn, Error=IoError>>;

	/// Listen on the given multi-addr.
	/// Returns the address back if it isn't supported.
	fn listen_on(&mut self, handle: &Handle, addr: Multiaddr) -> Result<Self::Listener, Multiaddr> {
		if let Ok(socket_addr) = multiaddr_to_socketaddr(&addr) {
			Ok(Box::new(futures::future::result(TcpListener::bind(&socket_addr, handle)).map(|listener| {
				// Pull out a stream of sockets for incoming connections
				listener.incoming().map(|x| x.0)
			}).flatten_stream()))
		} else {
			Err(addr)
		}
	}

	/// Dial to the given multi-addr.
	/// Returns either a future which may resolve to a connection,
	/// or gives back the multiaddress.
	fn dial(&mut self, handle: &Handle, addr: Multiaddr) -> Result<Self::Dial, Multiaddr> {
		if let Ok(socket_addr) = multiaddr_to_socketaddr(&addr) {
			Ok(Box::new(TcpStream::connect(&socket_addr, handle)))
		} else {
			Err(addr)
		}
	}
}

// This type of logic should probably be moved into the multiaddr package
fn multiaddr_to_socketaddr(addr: &Multiaddr) -> Result<SocketAddr, &Multiaddr>  {
	let protocols = addr.protocol();
	match (protocols[0], protocols[1]) {
		(Protocol::IP4, Protocol::TCP) => {
			let bs = addr.as_slice();
			Ok(SocketAddr::new(
				IpAddr::V4(Ipv4Addr::new(bs[1], bs[2], bs[3], bs[4])),
				(bs[6] as u16) << 8 | bs[7] as u16
			))
		},
		(Protocol::IP6, Protocol::TCP) => {
			let bs = addr.as_slice();
			if let Ok(Some(s)) = Protocol::IP6.bytes_to_string(&bs[1..17]) {
				if let Ok(ipv6addr) = s.parse() {
					return Ok(SocketAddr::new(IpAddr::V6(ipv6addr), (bs[18] as u16) << 8 | bs[19] as u16))
				}
			}
			Err(addr)
		},
		_ => Err(addr),
	}
}

#[test]
fn multiaddr_to_tcp_conversion() {
	use std::net::{Ipv6Addr};

	assert_eq!(
		multiaddr_to_socketaddr(&Multiaddr::new("/ip4/127.0.0.1/tcp/12345").unwrap()),
		Ok(SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), 12345))
	);
	assert_eq!(
		multiaddr_to_socketaddr(&Multiaddr::new("/ip4/255.255.255.255/tcp/8080").unwrap()),
		Ok(SocketAddr::new(IpAddr::V4(Ipv4Addr::new(255, 255, 255, 255)), 8080))
	);
	assert_eq!(
		multiaddr_to_socketaddr(&Multiaddr::new("/ip6/::1/tcp/12345").unwrap()),
		Ok(SocketAddr::new(IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1)), 12345))
	);
	assert_eq!(
		multiaddr_to_socketaddr(&Multiaddr::new("/ip6/ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff/tcp/8080").unwrap()),
		Ok(SocketAddr::new(IpAddr::V6(Ipv6Addr::new(65535, 65535, 65535, 65535, 65535, 65535, 65535, 65535)), 8080))
	);
}

#[test]
fn communicating_between_dialer_and_listener() {
	use tokio_core::reactor::Core;
	use std::io::Write;

	/// This thread is running the listener
	/// while the main thread runs the dialer
	std::thread::spawn(move || {
		let addr = Multiaddr::new("/ip4/127.0.0.1/tcp/12345").unwrap();
		let mut ev_loop = Core::new().unwrap();
		let handle = ev_loop.handle();
		let server = TCP.listen_on(&handle, addr).unwrap().for_each(|sock| {
			// Define what to do with the socket that just connected to us
			// Which in this case is read 3 bytes
			let handle_conn = tokio_io::io::read_exact(sock, [0; 3]).map(|(_, buf)| {
				println!("Actually read {:?}", buf);
				assert_eq!(buf, [1,2,3])
			}).map_err(|err| {
				panic!("IO error {:?}", err)
			});

			// Spawn the future as a concurrent task
			handle.spawn(handle_conn);

			Ok(())
		});

		// Spin up the server on the event loop
		ev_loop.run(server).unwrap();
	});
	let addr = Multiaddr::new("/ip4/127.0.0.1/tcp/12345").unwrap();
	let mut ev_loop = Core::new().unwrap();
	let handle = ev_loop.handle();
	// Obtain a future socket through dialing
	let socket = TCP.dial(&handle, addr.clone()).unwrap();
	// Define what to do with the socket once it's obtained
	let action = socket.then(|sock| {
		match sock {
			Ok(mut s) => {
				let written = s.write(&[0x1,0x2,0x3]).unwrap();
				Ok(written)
			}
			Err(x) => Err(x)
		}
	});
	// Execute the future in our event loop
	ev_loop.run(action).unwrap();
	std::thread::sleep(std::time::Duration::from_millis(1000));
}