Re: Reading multiple channels under the same session

[g4-lisz@xxxxxxxxxxxx]

On 29.01.19 23:23, Alberto Garcia wrote:

> Hi,
>
> First of all I want to clarify that I'm doing my tests in Windows so I
> had to adapt the code to work in it (I modified the minimum possible
> from your code). I'm worried that the problem may be in the windows
> support of libssh. 
>
> I've been able to reproduce in a "consistent" way the crash. I wrote a
> simple python code that in 5 threads uses the proxy socks to do
> requests and it crashes immediately.  It ALWAYS crashes
> within cb_readsock but at different places in it which makes me think
> that is a race condition of some sort which is weird because I'm only
> threading at ssh_bind_accept().
>
> If there is anything that comes to your mind please let me know.
>
That's interesting! I always wanted to make it work on Windows, but I
did not find the time to get into all this Visual Studio stuff... I'm a
Linux guy ;-)

You also compiled libssh by yourself, or you downloaded it from somewhere?

On Linux my code is working - At least I tested it with 5 parallel
channels over one session with OpenSSH client:

ssh -v -v -p2022 -N myuser@localhost -L8088:somedomain.com:80

The problem is to find a website which does not send redirects or has a
baseurl tag. I used the site of a client, so I had to remove the name
here. But as you can see there are a few channels open simultaneously:

debug1: Connection to port 8088 forwarding to XXXXXXX port 80 requested.
debug2: fd 11 setting TCP_NODELAY
debug2: fd 11 setting O_NONBLOCK
debug1: channel 6: new [direct-tcpip]
debug1: Connection to port 8088 forwarding to XXXXXXX port 80 requested.
debug2: fd 12 setting TCP_NODELAY
debug2: fd 12 setting O_NONBLOCK
debug1: channel 7: new [direct-tcpip]
debug2: channel 4: open confirm rwindow 32000 rmax 35000
debug2: channel 5: open confirm rwindow 32000 rmax 35000
debug2: channel 6: open confirm rwindow 32000 rmax 35000
debug2: channel 7: open confirm rwindow 32000 rmax 35000
debug2: channel 3: rcvd adjust 1248429
debug2: channel 4: rcvd adjust 1248438
debug2: channel 5: rcvd adjust 1248443
debug2: channel 6: rcvd adjust 1248435
debug2: channel 7: rcvd adjust 1248429
debug2: channel 4: window 1997957 sent adjust 99195
debug2: channel 5: window 1998454 sent adjust 98698
debug2: channel 4: window 1992032 sent adjust 105120
debug2: channel 2: rcvd eof
debug2: channel 2: output open -> drain
debug2: channel 2: obuf empty
debug2: channel 2: close_write
debug2: channel 2: output drain -> closed
debug2: channel 2: rcvd close
debug2: channel 2: close_read
debug2: channel 2: input open -> closed
debug2: channel 2: send close
debug2: channel 2: is dead
debug2: channel 2: garbage collecting

I will stresstest this code a bit further tomorrow.

Regards,
Till