From 375551542f8ded99bc80b65b663174e806fa4dda Mon Sep 17 00:00:00 2001
From: Nilstrieb <48135649+Nilstrieb@users.noreply.github.com>
Date: Wed, 9 Feb 2022 11:32:51 +0100
Subject: [PATCH] connectoin

---
 amqp_transport/src/connection.rs | 58 ++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 amqp_transport/src/connection.rs

diff --git a/amqp_transport/src/connection.rs b/amqp_transport/src/connection.rs
new file mode 100644
index 0000000..a910702
--- /dev/null
+++ b/amqp_transport/src/connection.rs
@@ -0,0 +1,58 @@
+use anyhow::{bail, ensure, Result};
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::TcpStream;
+use tracing::{debug, error};
+
+pub struct Connection {
+    stream: TcpStream,
+}
+
+impl Connection {
+    pub fn new(stream: TcpStream) -> Self {
+        Self { stream }
+    }
+
+    pub async fn start(mut self) {
+        match self.run().await {
+            Ok(()) => {}
+            Err(err) => error!(%err, "Error during processing of connection"),
+        }
+    }
+
+    pub async fn run(&mut self) -> Result<()> {
+        self.negotiate_version().await?;
+        Ok(())
+    }
+
+    async fn negotiate_version(&mut self) -> Result<()> {
+        const HEADER_SIZE: usize = 8;
+        const PROTOCOL_VERSION: &[u8] = &[0, 9, 1];
+        const PROTOCOL_HEADER: &[u8] = b"AMQP\0\0\x09\x01";
+
+        debug!("Negotiating version");
+
+        let mut read_header_buf = [0; HEADER_SIZE];
+
+        self.stream.read_exact(&mut read_header_buf).await?;
+
+        debug!(received_header = ?read_header_buf,"Received protocol header");
+
+        ensure!(
+            &read_header_buf[0..5] == b"AMQP\0",
+            "Received wrong protocol"
+        );
+
+        let version = &read_header_buf[5..8];
+
+        self.stream.write_all(PROTOCOL_HEADER).await?;
+
+        if version == PROTOCOL_VERSION {
+            debug!(?version, "Version negotiation successful");
+            Ok(())
+        } else {
+            debug!(?version, expected_version = ?PROTOCOL_VERSION, "Version negotiation failed, unsupported version");
+            self.stream.shutdown().await?;
+            bail!("Unsupported protocol version {:?}", version);
+        }
+    }
+}