Performance during MiTM

[hazcod]

Hi, just to let you know that when using mitmHandler, a lot of CPU time is spent in mitm_handler.transmit.

Not sure if the client-side connections are pooled?

[telanflow]

Yes, I know. MITM does not use connection pooling, and I am still considering a solution.

The tunnel agent has used the connection pool.

mps/mitm_handler.go

Lines 133 to 193 in 668b4ac

	func (mitm *MitmHandler) transmit(clientConn net.Conn, originalReq *http.Request, tlsConfig *tls.Config) {
	// TODO: cache connections to the remote website
	rawClientTls := tls.Server(clientConn, tlsConfig)
	if err := rawClientTls.Handshake(); err != nil {
	ConnError(clientConn)
	_ = rawClientTls.Close()
	return
	}
	defer rawClientTls.Close()
	clientTlsReader := bufio.NewReader(rawClientTls)
	for !isEof(clientTlsReader) {
	req, err := http.ReadRequest(clientTlsReader)
	if err != nil {
	break
	}
	// since we're converting the request, need to carry over the original connecting IP as well
	req.RemoteAddr = originalReq.RemoteAddr
	if !httpsRegexp.MatchString(req.URL.String()) {
	req.URL, err = url.Parse("https://" + originalReq.Host + req.URL.String())
	}
	if err != nil {
	return
	}
	var resp *http.Response
	// Copying a Context preserves the Transport, Middleware
	ctx := mitm.Ctx.WithRequest(req)
	resp, err = ctx.Next(req)
	if err != nil {
	return
	}
	var (
	// Body buffer
	buffer = new(bytes.Buffer)
	// Body size
	bufferSize int64
	)
	buf := mitm.buffer().Get()
	bufferSize, err = io.CopyBuffer(buffer, resp.Body, buf)
	mitm.buffer().Put(buf)
	if err != nil {
	_ = resp.Body.Close()
	return
	}
	resp.Body.Close()
	resp.ContentLength = bufferSize
	resp.Header.Set("Content-Length", strconv.Itoa(int(bufferSize)))
	resp.Body = ioutil.NopCloser(buffer)
	err = resp.Write(rawClientTls)
	if err != nil {
	return
	}
	}
	}

[telanflow]

the reason for the TLS handshake should be that you did not reuse the connection for each request.

You need to pay attention to:

The client needs to reuse the connection every time it initiates a http request. Otherwise the http request will re-create the connection, resulting in repeated TLS handshake

[hazcod]

Hi @telanflow , i'll check the http protocol version.
So what does this todo refer to then? https://github.com/telanflow/mps/blob/master/mitm_handler.go#L134

[hazcod]

@telanflow Interesting, I've disabled connection: close on request & response and always use HTTP/1.1.