x11 - X11 channel 到底是什么

Question

到目前为止我发现的所有 X11 文档中都写有这样的内容

Communication between server and clients is done by exchanging packets over a channel. The connection is established by the client (how the client is started is not specified in the protocol). (from wikipedia)

我没能找到这个 channel 到底是什么？例如网络 channel ？是在港口吗？它是内存映射吗？感谢您的帮助。

Answer 1

“ channel ”的措辞故意含糊不清，因为它可以通过本地套接字、远程连接(例如 SSH)、命名管道或其他允许客户端/服务器双向通信的方法。也就是说，“ channel ”只是两点之间促进数据交换的连接。

通过SSH进行X11转发时， channel 为SSH连接。例如，参见 SSH man 页面:

$ man ssh

X11 connections and arbitrary TCP/IP ports can also be forwarded over the secure channel.

或根据 x.org文档:

The communications channel between an X client and server is full-duplex: either side can send a message to the other at any time. This is canonically implemented over a TCP/IP socket interface, though other communications channels are often used, including Unix domain sockets, named pipes and shared memory. The channel must provide a reliable, ordered byte stream---the X protocol provides no mechanism for reordering or resending packets.