fix(tcpreuse): handle connection that failed to be sampled

p2p/transport/tcpreuse/demultiplex.go

@@ -40,35 +40,35 @@ func (t DemultiplexedConnType) IsKnown() bool {
 
 // identifyConnType attempts to identify the connection type by peeking at the
 // first few bytes.
-// It Callers must not use the passed in Conn after this
-// function returns. if an error is returned, the connection will be closed.
+// Its Callers must not use the passed in Conn after this function returns.
+// If an error is returned, the connection will be closed.
 func identifyConnType(c manet.Conn) (DemultiplexedConnType, manet.Conn, error) {
 	if err := c.SetReadDeadline(time.Now().Add(identifyConnTimeout)); err != nil {
 		closeErr := c.Close()
 		return 0, nil, errors.Join(err, closeErr)
 	}
 
-	s, c, err := sampledconn.PeekBytes(c)
+	s, peekableConn, err := sampledconn.PeekBytes(c)
 	if err != nil {
 		closeErr := c.Close()
 		return 0, nil, errors.Join(err, closeErr)
 	}
 
-	if err := c.SetReadDeadline(time.Time{}); err != nil {
-		closeErr := c.Close()
+	if err := peekableConn.SetReadDeadline(time.Time{}); err != nil {
+		closeErr := peekableConn.Close()
 		return 0, nil, errors.Join(err, closeErr)
 	}
 
 	if IsMultistreamSelect(s) {
-		return DemultiplexedConnType_MultistreamSelect, c, nil
+		return DemultiplexedConnType_MultistreamSelect, peekableConn, nil
 	}
 	if IsTLS(s) {
-		return DemultiplexedConnType_TLS, c, nil
+		return DemultiplexedConnType_TLS, peekableConn, nil
 	}
 	if IsHTTP(s) {
-		return DemultiplexedConnType_HTTP, c, nil
+		return DemultiplexedConnType_HTTP, peekableConn, nil
 	}
-	return DemultiplexedConnType_Unknown, c, nil
+	return DemultiplexedConnType_Unknown, peekableConn, nil
 }
 
 // Matchers are implemented here instead of in the transports so we can easily fuzz them together.

p2p/transport/tcpreuse/listener.go

@@ -231,8 +231,6 @@ func (m *multiplexedListener) run() error {
 			t, c, err := identifyConnType(c)
 			if err != nil {
 				connScope.Done()
-				closeErr := c.Close()
-				err = errors.Join(err, closeErr)
 				log.Debugf("error demultiplexing connection: %s", err.Error())
 				return
 			}