Termtunnel

Termtunnel is a tool that allows you to create a tunnel via multiple hops or fight against intranet isolation in a very simple way. As lrzsz can, termtunnel supports not only file transfer but also network proxy.

Quickstart

You must ensure that the termtunnel binary exists on both the local and remote first.

Please use termtunnel to open any locally terminal application such as ssh, bash, etc.

sh-3.2$ >> termtunnel ssh [email protected]

After running, the terminal output is the same as without the termtunnel prefix, and you can keep your normal usage habits.

sh-3.2$ >> termtunnel ssh [email protected]
root@host:~# echo loulou
loulou
root@host:~# uname -a
Linux 5.10.0-11-amd64 #1 SMP Debian 5.10.92-2 (2022-02-28) x86_64 GNU/Linux

When a tunnel needs to be established, just run command termtunnel -a on that remote host.

In the remote termtunnel console, you are allowed to download and upload files or create socks5 proxy.

For example, you can execute termtunnel ssh [email protected] locally, then start /tmp/termtunnel -a on the ssh host to enter the interactive console, and then you can type upload to upload a local file to remote or create a port forward. supported commands are listed in the REPL Command section.

sh-3.2$ >> termtunnel ssh [email protected]
root@host:~# /tmp/termsocks -a
termtunnel>> help

Install

• Linux

  • Provide prebuilt static binaries to run. See lastest releases

• MacOS

  • brew install beordle/tap/termtunnel

• Windows

  • Provide prebuilt binaries to run. Download

Working principle

As you can imagine, we use the method of tapping the string to upload a message to the remote in terminal, and then get a message back from the remote, and in this way, we get a point-to-point transmission channel.

flowchart LR
    local(temrtunnel local) <--> ssh
    ssh <--> sshd
    sshd <--> bash
    bash <--> remote(termtunnel remote)

Termtunnel use pty to control local application, write data to its stdin, and read data from its stdout. and then the local application stdin and stdout be linked with remote termtunnel.

REPL Command

This documentation may be out of date, please refer to the output of the help command.

• help:

  • view command help

• local_listen

  • local_listen [local_host] [local_port] [remote_host] [remote_port]
  • when remote_port==0, the service listen on remote_port will be a socks5.

• remote_listen

  • remote_listen [remote_host] [remote_port] [local_host] [local_port]
  • when remote_port==0, the service listen on remote_port will be a socks5.

• download

  • download a file

• upload

  • upload a file

Build from Source

Windows

Please use MSYS2 to compile under windows.

pacman -Syu libuv libuv-devel cmake make 
pacman -Syu openssh  # optional
cmake .
make

Other platform

cmake .
make

FAQ

1. Can I make the whole process unattended？ To reduce user intervention, you can try to use UNIX expect tool.
2. How to use it with tmux？ Out of the box. Designed with tmux in mind. But because of the implementation of tmux, the speed is very limited. If you want to improve the speed, you need to modify the source code and recompile tmux
3. My office network can't connect to apt, and yum, etc, can this program help me？ Yes, use remote_listen

License

This application is free software; you can redistribute it and/or modify it under the terms of the MIT license. See LICENSE file for details.