Merge pull request #1465 from microsoft/ab-tcp-handle-rst-packet

[inetstack] Handle RST packet from peer endpoint

src/rust/inetstack/mod.rs

@@ -88,15 +88,14 @@ impl SharedInetStack {
             runtime: runtime.clone(),
             layer4_endpoint,
         }));
-        runtime.insert_background_coroutine("bgc::inetstack::poll_recv", Box::pin(me.clone().poll().fuse()))?;
+        runtime.insert_background_coroutine("bgc::inetstack::poll", Box::pin(me.clone().poll().fuse()))?;
         Ok(me)
     }
 
     /// Scheduler will poll all futures that are ready to make progress.
     /// Then ask the runtime to receive new data which we will forward to the engine to parse and
     /// route to the correct protocol.
     pub async fn poll(mut self) {
-        timer!("inetstack::poll");
         loop {
             for _ in 0..MAX_RECV_ITERS {
                 self.layer4_endpoint.poll_once();

src/rust/inetstack/protocols/layer4/tcp/established/ctrlblk.rs

@@ -337,6 +337,11 @@ impl SharedControlBlock {
     pub fn get_state(&self) -> State {
         self.state
     }
+
+    pub fn set_state(&mut self, state: State) {
+        self.state = state;
+    }
+
     // This coroutine runs the close protocol.
     pub async fn close(&mut self) -> Result<(), Fail> {
         // Assert we are in a valid state and move to new state.

src/rust/inetstack/protocols/layer4/tcp/established/receiver.rs

@@ -188,7 +188,7 @@ impl Receiver {
             &mut seg_len,
             &mut cb,
         )?;
-        self.check_rst(&header)?;
+        self.check_and_process_rst(&header, &mut cb)?;
         self.check_syn(&header)?;
         self.process_ack(&header, &mut cb, now)?;
 
@@ -374,20 +374,16 @@ impl Receiver {
         Ok(())
     }
 
-    // Check the RST bit.
-    fn check_rst(&mut self, header: &TcpHeader) -> Result<(), Fail> {
-        if header.rst {
-            // TODO: RFC 5961 "Blind Reset Attack Using the RST Bit" prevention would have us ACK and drop if the new
-            // segment doesn't start precisely on RCV.NXT.
-
-            // Our peer has given up.  Shut the connection down hard.
-            info!("Received RST");
-            // TODO: Schedule a close coroutine.
-            let cause: String = format!("remote reset connection");
-            info!("check_rst(): {}", cause);
-            return Err(Fail::new(libc::ECONNRESET, &cause));
+    // TODO: RFC 5961 "Blind Reset Attack Using the RST Bit" prevention would have us ACK and drop if the new segment
+    // doesn't start precisely on RCV.NXT.
+    fn check_and_process_rst(&mut self, header: &TcpHeader, cb: &mut SharedControlBlock) -> Result<(), Fail> {
+        if !header.rst {
+            return Ok(());
         }
-        Ok(())
+        info!("Received RST: remote reset connection");
+        cb.set_state(State::Closed);
+        self.push_fin();
+        return Err(Fail::new(libc::ECONNRESET, "remote reset connection"));
     }
 
     // Check the SYN bit.