/aten-proxy

VNC protocol converter for ATEN iKVM products

Primary LanguageC++

aten-proxy

Introduction

aten-proxy is currently in development and not yet suitable for end-users.

ATEN iKVM products are often found in remote management interfaces providing the keyboard, video and mouse functionality. The official client relies on both Java and native libraries to connect. aten-proxy is a LibVNCServer based translator that allows the use of any VNC client. Since the protocol used by the ATEN iKVM is a raw bitmap encoding, aten-proxy might also be used as an accelerator over longer distance using LibVNCServer’s various compression features.

aten-proxy is intended as a replacement for chicken-aten-ikvm, a proof-of-concept fork of the Chicken VNC viewer modified for use with ATEN iKVM products.

Building

aten-proxy requires LibVNCServer, libev, pkg-config, and CMake. Once they are installed, run CMake.

mkdir build && cd build
cmake .. && make

This repository can also be built with Nix.

License

aten-proxy is licensed under the terms of the GNU General Public License (GPL), in order to comply with the terms of LibVNCServer. If the dependency on LibVNCServer is removed, the author is open to other licensing options.

Tasks

Disconnection and graceful termination

The keyboard interface seems to no longer pass keys after forcefully terminating aten-proxy.

Error handling

Most transient errors result in reconnection, and permanent errors result in abort().

Mouse support

Lazy initialisation

The backend is currently connected immediately, and remains connected at all times. The backend should only be connected while a client is present.

Authentication methods

Currently only LibVNCServer’s built-in authentication methods are available, and the upstream authentication is hardcoded.

[#C] Remote media

No work has yet been done on the remote media protocol.

Keymap support

The ATEN iKVM expects HID codes for key events, while the VNC protocol works with X11 keysyms. This presently works by assuming everything is using the same keyboard layout as the author.

For example, pressing “Shift” and “2” on my keyboard results in “@”. This is sent over VNC as XK_Shift_L and XK_at. aten-proxy is able to pass the shift key directly (HID usage 0xE1), but has to infer how XK_at should be handled. keymap.cc uses a hardcoded table and guesses that with the current modifier state, it should send the “2” key (HID usage 0x1f) to enter “@”.

Testing

aten-proxy has only been tested with a Supermicro X9SCM-iiF.

Performance

The code is written to be simple to understand and safe at the expense of runtime performance. The following areas should be reviewed:

Authors

  • Andrew Childs <lorne@cons.org.nz>