    rdp2tcp 0.1

rdp2tcp is a tunneling tool on top of remote desktop protocol (RDP). It uses RDP virtual channel capabilities to multiplex several ports forwarding over an already established rdesktop or FreeRDP session.

Available features:

tcp port forwarding
reverse tcp port forwarding
process stdin/out forwarding
SOCKS5 minimal support

The code is splitted into 2 parts:

the client running on the rdesktop or FreeRDP client side
the server running on the Terminal Server side

Once both rdp2tcp client and server are running, tunnels management is performed by the controller (on client side). The controller typically listen on localhost (port 8477) waiting for new tunnel registrations.

-[ client (rdesktop side) ]--------------------

First of all, rdesktop must be compiled with OOP patch (see INSTALL). The OOP patch comes with a additional rdesktop command line option.

-r addin:NAME:HANDLER[:OPT1[:OPTN]]

NAME: the name of the RDP virtual channel HANDLER: the path of the executable which handle the virtual channel. OPT: argument passed to HANDLER executable

The rdp2tcp client must be initialized when the rdesktop client starts.

rdesktop -r addin:rdp2tcp:/path/to/rdp2tcp <ip>

rdp2tcp client usage:

rdp2tcp [[HOST] PORT]

HOST: rdp2tcp controller hostname or IP address (default is 127.0.0.1). PORT: rdp2tcp controller port (default is 8477).

Several instances of rdp2tcp client can be run on a single rdesktop session:

rdesktop -r addin:rdp2tcp-1:/path/to/rdp2tcp:8477
-r addin:rdp2tcp-2:/path/to/rdp2tcp:8478 <ip>

After rdesktop is started with rdp2tcp channel configured, port forwarding can be configured by connecting to the controller and sending commands. All commands are ASCII and ends with a CR "\n".

List rdp2tcp managed sockets: "l\n"
Remove tunnel
"- LHOST LPORT\n"

LHOST: tunnel local host LPORT: tunnel local port
Start SOCKS5 proxy "s LHOST LPORT\n"

LHOST: proxy local host LPORT: proxy local port
stdin/stdout forwarding tunnel (bind on rdesktop) "x LHOST LPORT CMD\n"

LHOST: local listener host LPORT: local listener port CMD: command line to execute on Terminal Server host
TCP forwarding tunnel (bind on rdesktop) "t LHOST LPORT RHOST RPORT\n"

LHOST: local listener host LPORT: local listener port RHOST: remote target host RPORT: remote target port
TCP reverse-connect tunnel (bind on Terminal Server) "r LHOST LPORT RHOST RPORT\n"

LHOST: local target host LPORT: local target port RHOST: remote listener host RPORT: remote listener port

rdp2tcp.py (located in "tools" folder) can be used to manage tunnels with simple command lines. ex: "rdp2tcp.py add forward LHOST LPORT RHOST RPORT"

-[ client (FreeRDP side) ]--------------------

In FreeRDP, rdp2tcp has been available since version 2.0.0 (released on 2020-04-09). It can be used with the /rdp2tcp command-line parameter:

xfreerdp /u:myuser /v:myserver:3389 /rdp2tcp:/path/to/rdp2tcp/client/rdp2tcp

After FreeRDP is started, it is possible to configure port forwarding by connecting to the controller and sending commands. This is similar as when using rdesktop. rdp2tcp.py (located in "tools" folder) can also be used to manage tunnels.

-[ server (Terminal Server side) ]-------------

Before starting the rdp2tcp server, you must be logged on the Terminal Server with one or more rdp2tcp clients attached to rdesktop or FreeRDP.

The rdp2tcp server won't magically appear on the Terminal Server. So the rdp2tcp.exe executable must be first uploaded.

rdp2tcp.exe doesn't require to be run with a privileged Windows account.

Terminal Server policy may block file sharing through the RDP session. Thus you may have to find a way to upload the .exe binary on the remote system. The binary can be uploaded by scripting the TS input.

Uploading binary data to the server can be automated by encoding data to key stroke sequences that will be given to rdesktop as keyboard input.

The rdpupload script (located in "tools" folder) generates a X11 script. xte (http://hoopajoo.net/projects/xautomation.html) run the X11 script.

start rdesktop with rdp2tcp client
tools/rdpupload -x -f vb server/rdp2tcp.exe | xte"
focus on the rdesktop window within 5 seconds
xte will feed rdesktop with keyboard input. focused window must not change or you may get some trouble :)
run the Visual Basic script uploaded by xte.
run rdp2tcp server by using the executable generated by the Visual Basic script.

-[ dev ]---------------------------------------

edit Makefile / enable -DDEBUG
use client/memcheck.sh to use valgrind as a RDP channel wrapper
doxygen can be used to generate the project documentation "doxygen Doxyfile-client" --> docs/client/html "doxygen Doxyfile-server" --> docs/server/html
export DEBUG (-1 to 2) environment variable to print debug statements
export TRACE (00 to ff) environment variable to print function traces

bit 0: I/O buffer management 1: network socket
2: RDP virtual channel 3: events loop 4: process 5: rdp2tcp controller 6: tunnel management 7: SOCKS5 protocol

Rdp2tcp

Install / Use

README