weston-rdp - the RDP backend for Weston
The RDP backend allows to run a weston environment without
the need of specific graphic hardware, or input devices. Users can interact
with weston only by connecting using the RDP protocol.
The RDP backend uses FreeRDP to implement the RDP part, it acts as
a RDP server listening for incoming connections. It supports different
codecs for encoding the graphical content. Depending on what is supported by
the RDP client, the backend will encode images using remoteFx codec, NS
codec or will fallback to raw bitmapUpdate.
On the security part, the backend supports RDP security or TLS,
keys and certificates must be provided to the backend depending on which
kind of security is requested. The RDP backend will announce security
options based on which files have been given.
The RDP backend is multi-seat aware, so if two clients connect on
the backend, they will get their own seat.
The RDP backend uses the following entries from
weston.ini.
- refresh-rate=rate
- Specifies the desktop redraw rate in Hz. If unspecified, the default is
60Hz. Changing this may be useful if you have a faster than 60Hz display,
or if you want to reduce updates to reduce network traffic.
- tls-key=file
- The file containing the key for doing TLS security. To have TLS security
you also need to ship a file containing a certificate.
- tls-cert=file
- The file containing the certificate for doing TLS security. To have TLS
security you also need to ship a key file.
When the RDP backend is loaded, weston will understand the
following additional command line options.
- --address=address
- The IP address on which the RDP backend will listen for RDP connections.
By default it listens on 0.0.0.0.
- --port=port
- The TCP port to listen on for connections, it defaults to 3389.
- --no-clients-resize
- By default when a client connects on the RDP backend, it will instruct
weston to resize to the dimensions of the client's announced resolution.
When this option is set, weston will force the client to resize to its own
resolution.
- --no-remotefx-codec
- The RemoteFX compression codec is enabled by default, but it may be
necessary to disable it to work around incompatabilities between
implementations. This option may be removed in the future when all known
issues are resolved.
- --rdp4-key=file
- The file containing the RSA key for doing RDP security. As RDP security is
known to be insecure, this option should be avoided in production.
- --rdp-tls-key=file
- The file containing the key for doing TLS security. To have TLS security
you also need to ship a file containing a certificate.
- --rdp-tls-cert=file
- The file containing the certificate for doing TLS security. To have TLS
security you also need to ship a key file.
- --external-listener-fd=fd
- Specifies a file descriptor inherited from the process that launched
weston to be listened on for client connections. Only local (such as
AF_VSOCK) sockets should be used, as this will be considered to be a local
connection by the RDP backend, and TLS and RDP security will be bypassed.
To generate a key file to use for RDP security, you need the
winpr-makecert utility shipped with FreeRDP:
$ winpr-makecert -rdp -silent -n rdp-security
This will create a rdp-security.key file.
You can generate a key and certificate file to use with TLS
security using a typical openssl invocations:
$ openssl genrsa -out tls.key 2048
Generating RSA private key, 2048 bit long modulus
[...]
$ openssl req -new -key tls.key -out tls.csr
[...]
$ openssl x509 -req -days 365 -signkey tls.key -in tls.csr -out tls.crt
[...]
You will get the tls.key and tls.crt files to use with the RDP
backend.