From 3e7a1ee575235394fd98cfd23989a9d4b569b478 Mon Sep 17 00:00:00 2001
From: whitequark <pz@m-labs.hk>
Date: Wed, 28 Dec 2016 04:10:17 +0000
Subject: [PATCH] Implement the TCP FIN-WAIT-2 state.

---
 src/socket/tcp.rs | 59 +++++++++++++++++++++++++++++++----------------
 1 file changed, 39 insertions(+), 20 deletions(-)

diff --git a/src/socket/tcp.rs b/src/socket/tcp.rs
index e85e518..db4a9d5 100644
--- a/src/socket/tcp.rs
+++ b/src/socket/tcp.rs
@@ -514,7 +514,7 @@ impl<'a> TcpSocket<'a> {
                 let unacknowledged = self.tx_buffer.len() + control_len;
                 if !(ack_number >= self.local_seq_no &&
                      ack_number <= (self.local_seq_no + unacknowledged)) {
-                    net_trace!("tcp:{}:{}: unacceptable ACK ({} not in {}..{})",
+                    net_trace!("tcp:{}:{}: unacceptable ACK ({} not in {}...{})",
                                self.local_endpoint, self.remote_endpoint,
                                ack_number, self.local_seq_no, self.local_seq_no + unacknowledged);
                     return Err(Error::Malformed)
@@ -608,12 +608,19 @@ impl<'a> TcpSocket<'a> {
             }
 
             // FIN packets in FIN-WAIT-1 state change it to CLOSING.
-            (State::FinWait1, TcpRepr { control: TcpControl::Fin, .. })  => {
+            (State::FinWait1, TcpRepr { control: TcpControl::Fin, .. }) => {
                 self.remote_seq_no  += 1;
                 self.set_state(State::Closing);
                 self.retransmit.reset();
             }
 
+            // FIN packets in FIN-WAIT-2 state change it to TIME-WAIT.
+            (State::FinWait2, TcpRepr { control: TcpControl::Fin, .. }) => {
+                self.remote_seq_no  += 1;
+                self.set_state(State::TimeWait);
+                self.retransmit.reset();
+            }
+
             // ACK packets in CLOSE-WAIT state do nothing.
             (State::CloseWait, TcpRepr { control: TcpControl::None, .. }) => (),
 
@@ -1347,6 +1354,18 @@ mod test {
         s
     }
 
+    #[test]
+    fn test_fin_wait_2_fin() {
+        let mut s = socket_fin_wait_2();
+        send!(s, [TcpRepr {
+            control: TcpControl::Fin,
+            seq_number: REMOTE_SEQ + 1,
+            ack_number: Some(LOCAL_SEQ + 1 + 1),
+            ..SEND_TEMPL
+        }]);
+        assert_eq!(s.state, State::TimeWait);
+    }
+
     #[test]
     fn test_fin_wait_2_close() {
         let mut s = socket_fin_wait_2();
@@ -1372,6 +1391,24 @@ mod test {
         assert_eq!(s.state, State::Closing);
     }
 
+    // =========================================================================================//
+    // Tests for the TIME-WAIT state.
+    // =========================================================================================//
+    fn socket_time_wait() -> TcpSocket<'static> {
+        let mut s = socket_fin_wait_2();
+        s.state           = State::TimeWait;
+        s.remote_seq_no   = REMOTE_SEQ + 1 + 1;
+        s.remote_last_ack = REMOTE_SEQ + 1 + 1;
+        s
+    }
+
+    #[test]
+    fn test_time_wait_close() {
+        let mut s = socket_time_wait();
+        s.close();
+        assert_eq!(s.state, State::TimeWait);
+    }
+
     // =========================================================================================//
     // Tests for the CLOSE-WAIT state.
     // =========================================================================================//
@@ -1441,24 +1478,6 @@ mod test {
         assert_eq!(s.state, State::LastAck);
     }
 
-    // =========================================================================================//
-    // Tests for the TIME-WAIT state.
-    // =========================================================================================//
-    fn socket_time_wait() -> TcpSocket<'static> {
-        let mut s = socket_fin_wait_2();
-        s.state           = State::TimeWait;
-        s.remote_seq_no   = REMOTE_SEQ + 1 + 1;
-        s.remote_last_ack = REMOTE_SEQ + 1 + 1;
-        s
-    }
-
-    #[test]
-    fn test_time_wait_close() {
-        let mut s = socket_time_wait();
-        s.close();
-        assert_eq!(s.state, State::TimeWait);
-    }
-
     // =========================================================================================//
     // Tests for transitioning through multiple states.
     // =========================================================================================//