Develop Reference

Issue with providing load balancing information using AxMSTSCLib

I am trying to establish a remote desktop connection via a remote desktop session broker in my C# application using the 'AxInterop.MSTSCLib' where I encounter problems with the transfer of the load balancing information.
Basically, I create a new object and set the basic parameters. A connection directly to a single Remote Desktop (RD) server is already possible with this:
var rd = new AxMsRdpClient11NotSafeForScripting();
rd.Server = "target-server.domain.local";
rd.UserName = "user";
var secured = (MSTSCLib.IMsTscNonScriptable)rd.GetOcx();
secured.ClearTextPassword = "password";
The RD environment I want to connect to consists of multiple RD service collections, each managing one or more RD Servers. For new RD connections, RD clients connect to an RD broker server, which redirects the clients according to the individual load balancing information they provide.
To provide this load balancing info, using mstsc.exe and a .rdp file I provide the setting 'loadbalanceinfo:s:tsv://MS Terminal Services Plugin.1.99999' where '99999' is the name of the targeted RD Collection which works fine. To implement this in MSTSCLib, I have to set it with 'rd.AdvancedSettings9.LoadBalanceInfo'.
However, as this post on the Microsoft Technet forum also describes, the load balancing info string must first be re-encoded.
var lbinfo = "loadbalanceinfo:s:tsv://MS Terminal Services Plugin.1.99999";
if (lbinfo.Length % 2 == 1) lbinfo += " ";
lbinfo += "\r\n";
var b = Encoding.UTF8.GetBytes(lbinfo);
var final = Encoding.Unicode.GetString(b);
rd.AdvancedSettings9.LoadBalanceInfo = final;
According to the last comment in the Technet post, the number of bytes must be even, so a space (U+0020) is added if necessary.
With 'rd.Connect()' the connection is established and my client reaches the connection broker. In the first step, my connection request appears in the logs of the broker server:
[TerminalServices-SessionBroker (Operational)]
The Remote Desktop Connection Broker has received a connection request for user {user}.
Notes in the RDP file (TSV URL) = 'tsv://MS Terminal Services Plugin.1.99999 '
(note: there are two empty spaces at the end of the string)
Original application = NULL
The call comes from the redirection server = broker.domain.local
The redirector is configured as a virtual machine redirector.
Note the two spaces at the end of the TSV URL that gets added by the used code because the bytes count would be uneven otherwise. The only difference to mstsc.exe is that there is only one space (which is the new line break we also add I guess) displayed.
In the next step, the error occurs and our connection attempt fails. It says 'The farm specified for the connection does not exist.'
The OnDisconnected event is triggered and provides me the information: 'DiscReason: 3' and 'ExtendedDisconnectReason: 1040'.
My guess: Because of the space we add, the name of the RD collection can't be assigned correctly anymore. If we compare the passed information (loadbalanceinfo:s:tsv://MS Terminal Services Plugin.1.99999) on byte level, we also see that this added space is the only difference:
mstsc.exe
74 73 76 3a 2f 2f 4d 53 20 54 65 72 6d 69 6e 61 6c 20 53 65 72 76 69 63 65 73 20 50 6c 75 67 69 6e 2e 31 2e 39 39 39 39 39 0d 0a
AxMSTSCLib:
74 73 76 3a 2f 2f 4d 53 20 54 65 72 6d 69 6e 61 6c 20 53 65 72 76 69 63 65 73 20 50 6c 75 67 69 6e 2e 31 2e 39 39 39 39 39 20 0d 0a
Note the third last byte, the U+0020, which we added to achieve an even byte count.
If I do not add the space and the number of bytes (43) is thus not even, I see in WireShark that the TPKT packet is not even sent anymore. The broker server, according to its logs, also takes no notice of the connection attempt. The OnDisconnected event provides me the information:: 'DiscReason: 4' and 'ExtendedDisconnectReason: exDiscReasonNoInfo'. So it seems that the AxMSTSCLib already assumes that the byte number is even.
Unfortunately, I can't figure out how mstsc.exe manages to successfully transmit the same odd string. On the byte level, I work supposedly identically.
I have uploaded the entire byte contents of the TPKT packages here for better comparison: https://pastebin.com/tLtfWHiP
I am grateful for any ideas.
Thanks and regards
Lukas P.

I tried a lot before I came up with a solution: adding space, zero width space chars like \u200B, before the load balancing string, and behind it. But the rd broker didn't take it.
Solution:
In case of an odd number of bytes, if we put a dot (U+002E) in the right place, the rd session broker can extract the required identifier for the targeted rd collection and the connection will be established correctly.
private void RdpLogic()
{
AdvancedSettings9.LoadBalanceInfo = ToLoadBalanceString($"tsv://MS Terminal Services Plugin.1.lbinfo");
}
private string ToLoadBalanceString(string loadBalanceInfo)
{
var temp = loadBalanceInfo;
if (temp.Length % 2 == 1) temp = temp.Insert(temp.LastIndexOf('.'), ".");
var final = Encoding.Unicode.GetString(Encoding.UTF8.GetBytes(temp + "\r\n"));
return final;
}
Samples:
ToLoadBalanceString("tsv://MS Terminal Services Plugin.1.even")
Result: 'tsv://MS Terminal Services Plugin.1.even/r/n'
ToLoadBalanceString("tsv://MS Terminal Services Plugin.1.odd")
Results in 'tsv://MS Terminal Services Plugin.1..odd/r/n'

C# Renci SshNet The server response contains a null character at position 0x0000002A

i have multiple Raspberries running with SSH server:
(OpenSSH_7.4p1 Raspbian-10+deb9u7, OpenSSL 1.0.2u 20 Dec 2019).
And if i try to connect via Renci SshNet, i get the following error message:
Renci.SshNet.Common.SshConnectionException: "The server response
contains a null character at position 0x0000002A:
00000000 53 53 48 2D 32 2E 30 2D 4F 70 65 6E 53 53 48 5F
SSH-2.0-OpenSSH_ 00000010 37 2E 34 70 31 20 52 61 73 70 62 69 61 6E
2D 31 7.4p1 Raspbian-1 00000020 30 2B 64 65 62 39 75 37 0A 00
0+deb9u7..
A server must not send a null character before the Protocol Version
Exchange is complete.
More information is available here:
https://www.rfc-editor.org/rfc/rfc4253#section-4.2"
SshClient scClient = new SshClient("123.123.123.123", "pi", "raspberry");
scClient.Connect();
is it possible to change the behavior of the ssh server,
or even better; can i tell renci ssh to ignore these protocol errors?

I think it's a problem of the latest SSH.NET NuGet Package. Currently the newest is 2020.0.0. And the one prior to that is 2020.0.0-beta1.
2020.0.0 gives me this problem, 2020.0.0-beta1 does not.
I will report this issue on https://github.com/sshnet/SSH.NET/issues
EDIT:
2020.0.1 just got published. That doesn't seem to have this problem. I recommend you to try that version.

Read printer status after writing test string

I'm trying to write a string to a serial port, then send a command to tell the printer to return it's status in real time, if OK then send the next string.
I know how to create the form, create a serial port and write my string:
serialPort.Write("ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMN\n");
// send command to read status
// if status = 4, warn user & close port, if not...
// send next string
serialPort.Write("ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMN\n");
Where I'm having trouble is sending & receiving the real time status.
The command is:
Transmit real-time status
ASCII DLE EOTn [a]
Hex 10 04 n [a]
Decimal 16 4 n [a]
TM-T90, TM-T88IV, TM-U220 : 1 ≤ n ≤ 4, n = 7
TM-L90: 1 ≤ n ≤ 4, n = 8, a = 3 (when n = 8) (TM-L90 with Peeler)
1 ≤ n ≤ 4 (TM-L90 without Peeler)
n a Function
1 -- Transmit printer status
2 -- Transmit offline status
3 -- Transmit error status
4 -- Transmit roll paper sensor status
7 1 Transmit ink status A
2 Transmit ink status B
8 3 Transmit peeler status
All I care about is where n = 4 (Transmit roll paper sensor status)
If n returns 4, stop and close port with message to user that paper is low.
I will be using the same program for a 4 printers listed, like I said all I care about is if the status changes from 0 to 4.
I hope someone can help. Thank you.

Failed to open a handle to the device when opening GPIO pin

Everytime I open a GPIO pin I get this exception:
WinRT information: Failed to open a handle to the device.
A resource required for this operation is disabled.
I can't seem to find much information for this on the internet. Probably because UAP is still in a preview. And I don't think something is wrong with my code, it is almost the same one from the Blink example:
GpioController gpio = GpioController.GetDefault();
if (gpio != null)
{
var ledpin = gpio.OpenPin(11);
ledpin.Write(_light ? GpioPinValue.High : GpioPinValue.Low);
ledpin.SetDriveMode(GpioPinDriveMode.Output);
}

Only a subset of pins are available to usermode. Most pins are reserved by the system and cannot be accessed from usermode.
As far as I know pin 11 is not available. Try pin 12 or 13.
List of available Pins:
GPIO# Power-on Pull Header Pin
4 PullUp 7
5 PullUp 29
6 PullUp 31
12 PullDown 32
13 PullDown 33
16 PullDown 36
17 PullDown 11
18 PullDown 12
19 PullDown 35
20 PullDown 38
21 PullDown 40
22 PullDown 15
23 PullDown 16
24 PullDown 18
25 PullDown 22
26 PullDown 37
27 PullDown 13
35 PullUp Red Power LED
47 PullUp Green Activity LED
Edit: Added missing GPIOs

Calling WAMS from Windows Forms application, freezes

I have a simple Windows Azure Mobile Service. I can get data from it by IOS, now I want to do it from Windows Forms application. My problem, it is not working. It is very strange, because when I call the same code from unit test from the same solution, it works, but when from a Windows Forms app, it freezes. Project targets .net 4.5 and references WAMS client lib by nuget.
Here is my code:
var testTable = WAMSService.MobileService.GetTable<HBCDataLib.WAMS.Test>();
var testResult = testTable.Take(1000).ToListAsync().Result;
By investigating it by Fiddler, i can see this:
CONNECT xy.azure-mobile.net:443 HTTP/1.1
Host: xy.azure-mobile.net
Connection: Keep-Alive
A SSLv3-compatible ClientHello handshake was found. Fiddler extracted the parameters below.
Version: 3.1 (TLS/1.0)
Random: 52 A0 0F 12 01 B1 9A 53 9A 2C 43 13 BD AD 44 6E 9D FB 2E A1 92 FC 5A C0 15 EB 72 30 B9 29 C4 B6
SessionID: empty
Extensions:
renegotiation_info 00
server_name xy.azure-mobile.net
elliptic_curves 00 05 00 18 00 20
ec_point_formats 01 00
SessionTicket TLS empty
Ciphers:
[002F] TLS_RSA_AES_128_SHA
[0035] TLS_RSA_AES_256_SHA
[0005] SSL_RSA_WITH_RC4_128_SHA
[000A] SSL_RSA_WITH_3DES_EDE_SHA
[C013] TLS1_CK_ECDHE_RSA_WITH_AES_128_CBC_SHA
[C014] TLS1_CK_ECDHE_RSA_WITH_AES_256_CBC_SHA
[C009] TLS1_CK_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
[C00A] TLS1_CK_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
[0032] TLS_DHE_DSS_WITH_AES_128_SHA
[0038] TLS_DHE_DSS_WITH_AES_256_SHA
[0013] SSL_DHE_DSS_WITH_3DES_EDE_SHA
[0004] SSL_RSA_WITH_RC4_128_MD5
Compression:
[00] NO_COMPRESSION
It is trivial, and works from unit test from the same solution. So, is it restricted (?!) to call WAMS from Windows forms app? Or what could be the problem?
Thanks in advance!