tests: rework the actually useful tests to live in the integration crate

crates/irtt-server/tests/traffic_class.rs

@@ -0,0 +1,133 @@
+//! Observe the emitted IP byte, independently of protocol negotiation.
+#![cfg(target_os = "linux")]
+
+use std::{io::IoSliceMut, net::UdpSocket as StdSocket, os::fd::AsRawFd, time::Duration};
+
+use irtt_proto::{
+    decode_echo_reply, decode_open_reply, encode_request, OpenReply, Params, RequestToEncode,
+    FLAG_CLOSE,
+};
+use irtt_server::{Server, ServerConfig};
+use nix::sys::socket::{recvmsg, ControlMessageOwned, MsgFlags};
+use tokio::{net::UdpSocket, sync::oneshot, time::timeout};
+
+async fn exchange(client: &UdpSocket, request: &[u8], expected: u8) -> Vec<u8> {
+    client.send(request).await.unwrap();
+    loop {
+        client.readable().await.unwrap();
+        let packet = client.try_io(tokio::io::Interest::READABLE, || {
+            let mut bytes = [0; 2048];
+            let mut control = nix::cmsg_space!(u8);
+            let mut iov = [IoSliceMut::new(&mut bytes)];
+            let msg = recvmsg::<()>(
+                client.as_raw_fd(),
+                &mut iov,
+                Some(&mut control),
+                MsgFlags::MSG_DONTWAIT,
+            )?;
+            let size = msg.bytes;
+            let class = msg.cmsgs().unwrap().find_map(|message| match message {
+                ControlMessageOwned::Ipv4Tos(class) => Some(class),
+                _ => None,
+            });
+            assert_eq!(class, Some(expected));
+            Ok(bytes[..size].to_vec())
+        });
+        match packet {
+            Ok(packet) => return packet,
+            Err(error) if error.kind() == std::io::ErrorKind::WouldBlock => {}
+            Err(error) => panic!("receive failed: {error}"),
+        }
+    }
+}
+
+fn echo(opened: &OpenReply, sequence: u32) -> Vec<u8> {
+    encode_request(
+        RequestToEncode::Echo {
+            token: opened.token,
+            sequence,
+            params: &opened.params,
+            payload: &[],
+        },
+        None,
+    )
+    .unwrap()
+}
+
+#[tokio::test(flavor = "current_thread")]
+async fn every_open_echo_and_server_close_applies_its_own_raw_traffic_class() {
+    timeout(Duration::from_secs(8), async {
+        let maximum = Duration::from_millis(1);
+        let mut server = Server::bind(
+            "127.0.0.1:0".parse().unwrap(),
+            ServerConfig::default()
+                .with_min_send_interval(Duration::ZERO)
+                .with_idle_timeout(Duration::MAX)
+                .with_max_test_duration(maximum),
+        )
+        .await
+        .unwrap();
+        let addr = server.local_addr().unwrap();
+        let (shutdown, stopped) = oneshot::channel();
+        let task = tokio::spawn(async move {
+            server
+                .run(async {
+                    let _ = stopped.await;
+                })
+                .await
+        });
+        let socket = StdSocket::bind("127.0.0.1:0").unwrap();
+        socket2::SockRef::from(&socket)
+            .set_recv_tos_v4(true)
+            .unwrap();
+        socket.set_nonblocking(true).unwrap();
+        let client = UdpSocket::from_std(socket).unwrap();
+        client.connect(addr).await.unwrap();
+        let mut sessions = Vec::new();
+        // Each new OPEN follows a prior ECHO. The first raw byte also includes
+        // ECN bits: neither a codepoint shift nor masking would preserve it.
+        for (requested, class) in [(185, 185), (32, 32), (0, 0), (256, 0), (-1, 0)] {
+            let params = Params {
+                dscp: requested,
+                ..Params::with_protocol_defaults()
+            };
+            let request = encode_request(
+                RequestToEncode::Open {
+                    params: &params,
+                    no_test: false,
+                },
+                None,
+            )
+            .unwrap();
+            let packet = exchange(&client, &request, 0).await;
+            let opened = decode_open_reply(&packet, None).unwrap();
+            assert_eq!(opened.params.dscp, requested);
+            let packet = exchange(&client, &echo(&opened, 0), class).await;
+            assert_eq!(
+                decode_echo_reply(&packet, &opened.params, None)
+                    .unwrap()
+                    .flags
+                    & FLAG_CLOSE,
+                0
+            );
+            sessions.push((opened, class));
+        }
+        // Every session has now served its first echo. Waiting past all duration
+        // deadlines is safe under oversleep; idle expiry cannot intervene.
+        tokio::time::sleep(maximum + Duration::from_secs(2)).await;
+        for (opened, class) in sessions {
+            let packet = exchange(&client, &echo(&opened, 1), class).await;
+            assert_ne!(
+                decode_echo_reply(&packet, &opened.params, None)
+                    .unwrap()
+                    .flags
+                    & FLAG_CLOSE,
+                0
+            );
+        }
+        shutdown.send(()).unwrap();
+        task.await.unwrap().unwrap();
+    })
+    .await
+    .expect("marked runtime exchanges did not complete");
+}