Browser Dialer

BETA v1.4.1+

Background

Based on an idea from 2020open in new tag, a concise WSS Browser Dialer has been implemented using native JS, achieving true browser TLS fingerprints and behavioral characteristics. However, WSS still has significant issues with ALPN, so the next step is to forward HTTP/2 and QUIC through the browser."

Xray & JS

A very simple and clever communication mechanism has been created：

  • Xray listens on address port A as an HTTP service, and the browser accesses A to load the JS in the webpage.
  • The JS actively establishes a WebSocket connection to A. After a successful connection, Xray sends the connection to the channel.
  • When a connection needs to be established, Xray receives an available connection from the channel and sends the target URL and optional early data.
  • Once the JS successfully connects to the target, it informs Xray and continues to use this conn to bi-directionally forward data. Connection closing behavior is synchronized.
  • After the connection is used, it will be closed, but the JS ensures that there is always a new idle connection available."

Early data

According to the browser's needs, the early data mechanism has been adjusted as follows:

  • The server response header will contain the requested Sec-WebSocket-Protocol, which also initially obfuscates the length characteristic of the WSS handshake response.
  • The encoding used for early data for browsers is base64.RawURLEncoding instead of StdEncoding, and the server has made it compatible.
  • In addition, due to Xray-core#375open in new tag recommendations for ?ed=2048, this PR also increased server MaxHeaderBytes by 4096. (Although it seems like it would work without modification.)

Configuration v1.4.1

This is an exploratory process, and the configuration method used when both sides are Xray-core v1.4.1 is as follows:

  • Prepare a usable WSS configuration, making sure to fill in the domain name for the address. If you need to specify an IP address, configure DNS or system hosts.
  • If browser traffic will also pass through Xray-core, be sure to set this domain name as a direct connection, otherwise it will cause traffic looping.
  • Set the environment variable to specify the address port to listen on, such as XRAY_BROWSER_DIALER = 127.0.0.1:8080.
  • First run Xray-core, then use any browser to access the specified address port, and you can also check Console and Network with F12.
  • The browser will limit the number of WebSocket connections, so it is recommended to enable Mux.Cool.