diff --git a/src/tun2proxy.rs b/src/tun2proxy.rs
index 46b6d68..75a36f9 100644
--- a/src/tun2proxy.rs
+++ b/src/tun2proxy.rs
@@ -690,6 +690,45 @@ impl<'a> TunToProxy<'a> {
         Ok(())
     }
 
+    fn process_incoming_tcp_packets(
+        &mut self,
+        first_packet: bool,
+        manager: &Rc<dyn ConnectionManager>,
+        info: &ConnectionInfo,
+        origin_dst: SocketAddr,
+        frame: &[u8],
+    ) -> Result<()> {
+        if first_packet {
+            let proxy_handler = manager.new_proxy_handler(info, false)?;
+            let server = manager.get_server_addr();
+            let state = self.create_new_tcp_connection_state(server, origin_dst, proxy_handler, false)?;
+            self.connection_map.insert(info.clone(), state);
+
+            log::info!("Connect done {} ({})", info, origin_dst);
+        } else if !self.connection_map.contains_key(info) {
+            log::trace!("Drop middle session {} ({})", info, origin_dst);
+            return Ok(());
+        } else {
+            log::trace!("Subsequent packet {} ({})", info, origin_dst);
+        }
+
+        // Inject the packet to advance the remote proxy server smoltcp socket state
+        self.device.inject_packet(frame);
+
+        // Having advanced the socket state, we expect the socket to ACK
+        // Exfiltrate the response packets generated by the socket and inject them
+        // into the tunnel interface.
+        self.expect_smoltcp_send()?;
+
+        // Read from the smoltcp socket and push the data to the connection handler.
+        self.tunsocket_read_and_forward(info)?;
+
+        // The connection handler builds up the connection or encapsulates the data.
+        // Therefore, we now expect it to write data to the server.
+        self.write_to_server(info)?;
+        Ok(())
+    }
+
     // A raw packet was received on the tunnel interface.
     fn receive_tun(&mut self, frame: &mut [u8]) -> Result<(), Error> {
         let mut handler = || -> Result<(), Error> {
@@ -698,41 +737,14 @@ impl<'a> TunToProxy<'a> {
                 log::debug!("{}, ignored", error);
                 return Ok(());
             }
-            let (info, _first_packet, payload_offset, payload_size) = result?;
+            let (info, first_packet, payload_offset, payload_size) = result?;
             let origin_dst = SocketAddr::try_from(&info.dst)?;
             let info = self.preprocess_origin_connection_info(info)?;
 
             let manager = self.get_connection_manager().ok_or("get connection manager")?;
 
             if info.protocol == IpProtocol::Tcp {
-                if _first_packet {
-                    let proxy_handler = manager.new_proxy_handler(&info, false)?;
-                    let server = manager.get_server_addr();
-                    let state = self.create_new_tcp_connection_state(server, origin_dst, proxy_handler, false)?;
-                    self.connection_map.insert(info.clone(), state);
-
-                    log::info!("Connect done {} ({})", info, origin_dst);
-                } else if !self.connection_map.contains_key(&info) {
-                    log::trace!("Drop middle session {} ({})", info, origin_dst);
-                    return Ok(());
-                } else {
-                    log::trace!("Subsequent packet {} ({})", info, origin_dst);
-                }
-
-                // Inject the packet to advance the remote proxy server smoltcp socket state
-                self.device.inject_packet(frame);
-
-                // Having advanced the socket state, we expect the socket to ACK
-                // Exfiltrate the response packets generated by the socket and inject them
-                // into the tunnel interface.
-                self.expect_smoltcp_send()?;
-
-                // Read from the smoltcp socket and push the data to the connection handler.
-                self.tunsocket_read_and_forward(&info)?;
-
-                // The connection handler builds up the connection or encapsulates the data.
-                // Therefore, we now expect it to write data to the server.
-                self.write_to_server(&info)?;
+                self.process_incoming_tcp_packets(first_packet, &manager, &info, origin_dst, frame)?;
             } else if info.protocol == IpProtocol::Udp {
                 let port = info.dst.port();
                 let payload = &frame[payload_offset..payload_offset + payload_size];