From 44b7c0f55e2866600c3f305cf6432a4279541284 Mon Sep 17 00:00:00 2001
From: Datong Sun <dndx@idndx.com>
Date: Thu, 16 Sep 2021 22:17:47 -0700
Subject: [PATCH] fix(fake_tcp) fixed incorrect RST SEQ/ACK

---
 src/bin/client.rs   | 12 +++++++++---
 src/fake_tcp/mod.rs |  4 ++--
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/bin/client.rs b/src/bin/client.rs
index 630f25a..5142042 100644
--- a/src/bin/client.rs
+++ b/src/bin/client.rs
@@ -64,8 +64,8 @@ async fn main() {
     info!("Created TUN device {}", tun.name());
 
     let udp_sock = Arc::new(UdpSocket::bind(local_addr).await.unwrap());
-    let connections = Mutex::new(LruCache::<SocketAddrV4, Arc<Socket>>::with_expiry_duration(
-        UDP_TTL,
+    let connections = Arc::new(Mutex::new(
+        LruCache::<SocketAddrV4, Arc<Socket>>::with_expiry_duration(UDP_TTL),
     ));
 
     let mut stack = Stack::new(tun);
@@ -96,8 +96,10 @@ async fn main() {
                     }
 
                     assert!(connections.lock().await.insert(addr, sock.clone()).is_none());
+                    debug!("inserted fake TCP socket into LruCache");
                     let udp_sock = udp_sock.clone();
 
+                    let connections = connections.clone();
                     tokio::spawn(async move {
                         loop {
                             let mut buf_r = [0u8; MAX_PACKET_LEN];
@@ -105,7 +107,11 @@ async fn main() {
                                 Some(size) => {
                                     udp_sock.send_to(&buf_r[..size], addr).await.unwrap();
                                 },
-                                None => { return; },
+                                None => {
+                                    connections.lock().await.remove(&addr);
+                                    debug!("removed fake TCP socket from LruCache");
+                                    return;
+                                },
                             }
                         }
                     });
diff --git a/src/fake_tcp/mod.rs b/src/fake_tcp/mod.rs
index 6658810..f743e77 100644
--- a/src/fake_tcp/mod.rs
+++ b/src/fake_tcp/mod.rs
@@ -399,7 +399,7 @@ impl Stack {
                                 local_addr,
                                 remote_addr,
                                 0,
-                                tcp_packet.get_acknowledgement() + 1,
+                                tcp_packet.get_sequence() + 1,
                                 tcp::TcpFlags::RST,
                                 None,
                             );
@@ -410,8 +410,8 @@ impl Stack {
                         let buf = build_tcp_packet(
                             local_addr,
                             remote_addr,
+                            tcp_packet.get_acknowledgement(),
                             0,
-                            tcp_packet.get_acknowledgement() + 1,
                             tcp::TcpFlags::RST,
                             None,
                         );