[winswitch] UDP connection issues

[Antoine Martin]

Sorry for the slow response, this was a tricky one.

On 15/01/2020 20:56, Igor Bukanov via shifter-users wrote:
> Hi,
> 
> I am trying to setup a udp connection to xpra server on Linux from a a
> Linux client. Both server and client uses 3.0.5 version. I run the
> server using
> 
> xpra start --bind-udp=0.0.0.0:port
> --udp-auth=file:filename=.config/xpra/password :28
> 
> I can connect to it using ssh, but when I tried on the client:
> 
> xpra attach udp://server-ip:port/28
That's all correct.

> The client reported an error:
> 
> 2020-01-15 14:28:23,228 Xpra GTK3 X11 client version 3.0.5-r24939 64-bit
> ...
> 2020-01-15 14:28:25,966 Error: failed to connect, received
> 2020-01-15 14:28:25,966
> '8000000032108494958117100112459911111011611411110810548101105481011054810110548101100101108101101'
> 
> On the server side I see from the log:
> 
> 2020-01-15 13:30:25,696 Error: connection timed out: udp socket:
> 0.0.0.0:server_port <- client_ip:52119
> 
> The connection is done over OpenVPN and I can ping the client ip from
> the server.
Note that UDP has not been tested or used much lately and there will be
some improvements in the next release as I've just spotted some
sub-optimal behaviour.

> 
> Any clues?
Yes: there was a bug affecting all python3 builds, and since v3 switched
to python3 by default, this broke UDP for default installations.
(we should add regression tests for this)

This is now fixed and will be included in the next stable update.
For the gory details, see:
https://xpra.org/trac/ticket/2554

Cheers,
Antoine