Moved upstreams to their own dedicated namespace

Signed-off-by: Jacob Kiers <code@kiers.eu>

src/upstreams/mod.rs

@@ -0,0 +1,51 @@
+mod proxy_to_upstream;
+
+use log::debug;
+use serde::Deserialize;
+use std::error::Error;
+use tokio::io;
+use tokio::io::{AsyncRead, AsyncWrite, AsyncWriteExt};
+use tokio::net::TcpStream;
+
+pub use crate::upstreams::proxy_to_upstream::ProxyToUpstream;
+
+#[derive(Debug, Clone, Deserialize)]
+pub enum Upstream {
+    Ban,
+    Echo,
+    Proxy(ProxyToUpstream),
+}
+
+impl Upstream {
+    pub(crate) async fn process(&self, mut inbound: TcpStream) -> Result<(), Box<dyn Error>> {
+        match self {
+            Upstream::Ban => {
+                inbound.shutdown().await?;
+            }
+            Upstream::Echo => {
+                let (mut ri, mut wi) = io::split(inbound);
+                let inbound_to_inbound = copy(&mut ri, &mut wi);
+                let bytes_tx = inbound_to_inbound.await;
+                debug!("Bytes read: {:?}", bytes_tx);
+            }
+            Upstream::Proxy(config) => {
+                config.proxy(inbound).await?;
+            }
+        };
+        Ok(())
+    }
+}
+
+async fn copy<'a, R, W>(reader: &'a mut R, writer: &'a mut W) -> io::Result<u64>
+where
+    R: AsyncRead + Unpin + ?Sized,
+    W: AsyncWrite + Unpin + ?Sized,
+{
+    match io::copy(reader, writer).await {
+        Ok(u64) => {
+            let _ = writer.shutdown().await;
+            Ok(u64)
+        }
+        Err(_) => Ok(0),
+    }
+}