darkfi/src/net/transport.rs

use std::net::SocketAddr;

use async_trait::async_trait;
// TODO remove *
use futures::prelude::*;
use futures_rustls::{TlsAcceptor, TlsStream};
use url::Url;

use crate::Result;

mod upgrade_tls;
pub use upgrade_tls::TlsUpgrade;

mod tcp;
pub use tcp::TcpTransport;

mod tor;
pub use tor::TorTransport;

mod unix;
pub use unix::UnixTransport;

/// A helper function to convert SocketAddr to Url and add scheme
pub(crate) fn socket_addr_to_url(addr: SocketAddr, scheme: &str) -> Result<Url> {
    let url = Url::parse(&format!("{}://{}", scheme, addr))?;
    Ok(url)
}

/// Used as wrapper for stream used by  Transport trait
pub trait TransportStream: AsyncWrite + AsyncRead + Unpin + Send + Sync {}

/// Used as wrapper for listener used by Transport trait
#[async_trait]
pub trait TransportListener: Send + Sync + Unpin {
    async fn next(&self) -> Result<(Box<dyn TransportStream>, Url)>;
}

#[derive(Clone)]
pub enum TransportName {
    Tcp(Option<String>),
    Tor(Option<String>),
    Nym(Option<String>),
    Unix,
}

impl TryFrom<Url> for TransportName {
    type Error = crate::Error;

    fn try_from(url: Url) -> Result<Self> {
        let transport_name = match url.scheme() {
            "tcp" => Self::Tcp(None),
            "tcp+tls" | "tls" => Self::Tcp(Some("tls".into())),
            "tor" => Self::Tor(None),
            "tor+tls" => Self::Tor(Some("tls".into())),
            "nym" => Self::Nym(None),
            "nym+tls" => Self::Nym(Some("tls".into())),
            "unix" => Self::Unix,
            n => return Err(crate::Error::UnsupportedTransport(n.into())),
        };
        Ok(transport_name)
    }
}

/// The `Transport` trait serves as a base for implementing transport protocols.
/// Base transports can optionally be upgraded with TLS in order to support encryption.
/// The implementation of our TLS authentication can be found in the [`upgrade_tls`] module.
pub trait Transport {
    type Acceptor;
    type Connector;

    type Listener: Future<Output = Result<Self::Acceptor>>;
    type Dial: Future<Output = Result<Self::Connector>>;

    type TlsListener: Future<Output = Result<(TlsAcceptor, Self::Acceptor)>>;
    type TlsDialer: Future<Output = Result<TlsStream<Self::Connector>>>;

    fn listen_on(self, url: Url) -> Result<Self::Listener>
    where
        Self: Sized;

    fn upgrade_listener(self, acceptor: Self::Acceptor) -> Result<Self::TlsListener>
    where
        Self: Sized;

    fn dial(self, url: Url) -> Result<Self::Dial>
    where
        Self: Sized;

    fn upgrade_dialer(self, stream: Self::Connector) -> Result<Self::TlsDialer>
    where
        Self: Sized;
}