Merge pull request #1449 from microsoft/bugfix-inetstack-close-corout…

…ines

Bug Fix: Retransmit FIN on close

network_simulator/input/tcp/close/close-local-retransmission.pkt

@@ -32,6 +32,9 @@
 // Receive ACK on data packet.
 +.1 TCP < . seq 1(0) ack 1001 win 65535 <nop>
 
+// Send FIN again since no ack on it yet.
++.0 TCP > F. seq 1001(0) ack 1 win 65535 <nop>
+
 // Send completes
 +.0 wait(500, ...) = 9
 

network_simulator/input/tcp/close/close-remote-retransmission.pkt

@@ -0,0 +1,38 @@
+// Tests for remote close.
+
+// Establish a connection.
+ +.0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 500
++.2 connect(500, ..., ...) = 0
+
+// Send SYN segment.
++.0 TCP > S seq 0(0) win 65535 <mss 1450, wscale 0>
+// Receive SYN-ACK segment.
++.1 TCP < S. seq 0(0) ack 1 win 65535 <mss 1450, wscale 0>
+// Send ACK on SYN-ACK segment.
++.0 TCP > . seq 1(0) ack 1 win 65535 <nop>
+
+// Succeed to establish connection.
++.0 wait(500, ...) = 0
+
+// Receive FIN segment.
++.1 TCP < F. seq 1(0) ack 1 win 65535 <nop>
+// Send ACK on FIN segment.
++.0 TCP > . seq 1(0) ack 2 win 65534 <nop>
+
+// Close connection.
++.2 close(500) = 0
+
+// Send FIN segment.
++.0 TCP > F. seq 1(0) ack 2 win 65534 <nop>
+
+// Re-send FIN segment.
++1 TCP > F. seq 1(0) ack 2 win 65534 <nop>
+
+// Re-send FIN segment.
++3 TCP > F. seq 1(0) ack 2 win 65534 <nop>
+
+// Receive ACK on FIN segment.
++.1 TCP < . seq 2(0) ack 2 win 65535 <nop>
+
+// Succeed to close connection immediately.
++.0 wait(500, ...) = 0

src/rust/inetstack/protocols/layer4/tcp/established/background/mod.rs

@@ -25,11 +25,6 @@ pub async fn background(cb: SharedControlBlock, _dead_socket_tx: mpsc::Unbounded
     let receiver = async_timer!("tcp::established::background::receiver", cb2.poll()).fuse();
     pin_mut!(receiver);
 
-    let r = futures::select_biased! {
-        r = receiver => r,
-        r = acknowledger => r,
-        r = retransmitter => r,
-        r = sender => r,
-    };
+    let r = futures::join!(receiver, acknowledger, retransmitter, sender);
     error!("Connection terminated: {:?}", r);
 }