[inetstack] Bug Fix: Implement MSL

src/rust/inetstack/protocols/tcp/constants.rs

@@ -7,4 +7,5 @@ pub use crate::runtime::network::consts::{
     MAX_MSS,
     MAX_WINDOW_SCALE,
     MIN_MSS,
+    MSL,
 };

src/rust/inetstack/protocols/tcp/established/ctrlblk.rs

@@ -23,6 +23,7 @@ use crate::{
         ip::IpProtocol,
         ipv4::Ipv4Header,
         tcp::{
+            constants::MSL,
             established::{
                 congestion_control::{
                     self,
@@ -49,6 +50,7 @@ use crate::{
             types::MacAddress,
             NetworkRuntime,
         },
+        yield_with_timeout,
         SharedDemiRuntime,
         SharedObject,
     },
@@ -1125,10 +1127,10 @@ impl<N: NetworkRuntime> SharedControlBlock<N> {
     }
 
     // This coroutine runs the close protocol.
-    pub async fn close(&mut self) -> Result<(), Fail> {
+    pub async fn close(&mut self, linger: Option<Duration>) -> Result<(), Fail> {
         // Assert we are in a valid state and move to new state.
         match self.state {
-            State::Established => self.local_close().await,
+            State::Established => self.local_close(linger).await,
             State::CloseWait => self.remote_already_closed().await,
             _ => {
                 let cause: String = format!("socket is already closing");
@@ -1138,12 +1140,13 @@ impl<N: NetworkRuntime> SharedControlBlock<N> {
         }
     }
 
-    async fn local_close(&mut self) -> Result<(), Fail> {
+    async fn local_close(&mut self, linger: Option<Duration>) -> Result<(), Fail> {
         // 0. Set state.
         self.state = State::FinWait1;
         // 1. Send FIN.
         self.send_fin();
 
+        // 2. TIME_WAIT
         while self.state != State::TimeWait {
             // Wait for next packet.
             let (_, header, _) = self.recv_queue.pop(None).await?;
@@ -1178,14 +1181,9 @@ impl<N: NetworkRuntime> SharedControlBlock<N> {
             }
         }
 
-        // TODO: Get 2MSL value or linger option if set.
-        // TODO: Turn this on when our tests support it.
-        // let timeout_yielder: Yielder = Yielder::new();
-        // self.runtime
-        //     .get_timer()
-        //     .wait(Duration::from_secs(1), &timeout_yielder)
-        //     .await?;
-
+        // 3. TIMED_WAIT
+        let timeout: Duration = linger.unwrap_or(MSL * 2);
+        yield_with_timeout(timeout).await;
         self.state = State::Closed;
         Ok(())
     }

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

@@ -129,8 +129,8 @@ impl<N: NetworkRuntime> EstablishedSocket<N> {
         self.cb.pop(size).await
     }
 
-    pub async fn close(&mut self) -> Result<(), Fail> {
-        self.cb.close().await
+    pub async fn close(&mut self, linger: Option<Duration>) -> Result<(), Fail> {
+        self.cb.close(linger).await
     }
 
     pub fn remote_mss(&self) -> usize {

src/rust/inetstack/protocols/tcp/socket.rs

@@ -245,10 +245,12 @@ impl<N: NetworkRuntime> SharedTcpSocket<N> {
     }
 
     pub async fn close(&mut self) -> Result<Option<SocketId>, Fail> {
+        let linger: Option<Duration> = self.tcp_options.get_linger();
+
         match self.state {
             // Closing an active socket.
             SocketState::Established(ref mut socket) => {
-                socket.close().await?;
+                socket.close(linger).await?;
                 Ok(Some(SocketId::Active(socket.endpoints().0, socket.endpoints().1)))
             },
             // Closing a listening socket.

src/rust/runtime/network/consts.rs

@@ -20,6 +20,10 @@ pub const MIN_MSS: usize = FALLBACK_MSS;
 /// Maximum MSS Parameter for TCP
 pub const MAX_MSS: usize = u16::max_value() as usize;
 
+/// Maximum Segment Lifetime
+/// See: https://www.rfc-editor.org/rfc/rfc793.txt
+pub const MSL: Duration = Duration::from_secs(2);
+
 /// Delay timeout for TCP ACKs.
 /// See: https://www.rfc-editor.org/rfc/rfc5681#section-4.2
 pub const TCP_ACK_DELAY_TIMEOUT: Duration = Duration::from_millis(500);

src/rust/runtime/network/socket/option.rs

@@ -38,6 +38,9 @@ impl TcpSocketOptions {
 
 impl Default for TcpSocketOptions {
     fn default() -> Self {
-        Self { linger: None }
+        Self {
+            // Setting this to zero by default.
+            linger: Some(Duration::ZERO),
+        }
     }
 }