Custom channel support in NeutrinoRDP proxy

[lex-andreev]

Hello,

I use xrdp as a proxy using NeutrinoRDP module. So, my workflow in the same as mentioned in wiki:
RDP client -> xrdp load neutrino proxy module -> RDP server

My goal is to send some data from the RDP server side to the proxy using a custom static virtual channel.
Unfortunately, I ran out of ideas how to implement this.
I know there is a sample with the echo channel, but it doesn't help much since it's mainly for RDP client -> RDP server interaction without any proxies. As far as I know, static virtual channels are established during the initial connection at the basic settings exchange state. So, just calling WTSVirtualChannelOpen on the RDP server side would not be enough without "teaching" the NeutrinoRDP how to handle the custom channel.
If to call WTSVirtualChannelOpen for a custom channel on the server side now, it's failed with the ERROR_NOT_SUPPORTED error, which is quite reasonable.

Is there a way to implement this without digging deep into the core?

[lex-andreev]

I'll answer my own question.
It's enough to add the custom channel manually to self->mcs_layer->channel_list in xrdp_sec_process_mcs_data_channels, and it will work like a charm.