From 0836bc949aa8f9094008e7f51f0ffd81b8ed31bf Mon Sep 17 00:00:00 2001
From: whitequark <pz@m-labs.hk>
Date: Sun, 5 Mar 2017 05:31:12 +0000
Subject: [PATCH] Fix condition for acceptable RST|ACK in TCP SYN-SENT state.

---
 src/socket/tcp.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/socket/tcp.rs b/src/socket/tcp.rs
index b15fc29..1263b1d 100644
--- a/src/socket/tcp.rs
+++ b/src/socket/tcp.rs
@@ -674,7 +674,7 @@ impl<'a> TcpSocket<'a> {
             (State::SynSent, TcpRepr {
                 control: TcpControl::Rst, ack_number: Some(ack_number), ..
             }) => {
-                if ack_number != self.local_seq_no {
+                if ack_number != self.local_seq_no + 1 {
                     net_trace!("[{}]{}:{}: unacceptable RST|ACK in response to initial SYN",
                                self.debug_id, self.local_endpoint, self.remote_endpoint);
                     return Err(Error::Malformed)
@@ -1501,7 +1501,7 @@ mod test {
         send!(s, TcpRepr {
             control: TcpControl::Rst,
             seq_number: REMOTE_SEQ,
-            ack_number: Some(LOCAL_SEQ),
+            ack_number: Some(LOCAL_SEQ + 1),
             ..SEND_TEMPL
         });
         assert_eq!(s.state, State::Closed);