I have created a .net core app that runs very well on the Raspberry Pi.
I wish to try and connect this device to a wifi router or an access point from an iPhone.
After looking I know you can create a conf file and put it onto the sd card via a card reader.
What I would like to do is allow the user to enter their wifi details via my own interface and for my own c# program to make the chnages.
i have spent sometime but found no examples.
If anyone knows...
The usual approach for GUI based configuration is not to edit the system config files directly, but to talk through the configuration interface provided by the network daemons.
wpa_supplicant can be talked to through the wpa_cli utility. You use it by spawning wpa_cli as a separate process with stdio redirected into a pipe, into which/from you send the configurations commands.
Update: To talk to wpa_cli you'd create a process with redirected output. With Mono you'd do it as following
private void start_wpa_cli()
{
ProcessStartInfo psI = new ProcessStartInfo("wpa_cli");
psI.UseShellExecute = false;
psI.RedirectStandardInput = true;
psI.RedirectStandardOutput = true;
Process p = new Process();
p.StartInfo = psI;
p.Start();
StreamWriter sw = p.StandardInput;
sw.AutoFlush = true;
StreamReader sr = p.StandardOutput;
...
You can then send wpa_cli commands through sw and read the result from sr. The commands for wpa_cli you can find in its manpage.
If NetworkManager is used, you talk to it through its D-Bus interface. Update: To access D-Bus from .Net/Mono you could for example use https://github.com/mono/dbus-sharp
Related
I want to write simple application that communicates between the Hyper-V host and its virtual machine using Hyper-V sockets (netcat over vsock). In the Internet there are a few documents describing how to do it: Make your own integration services, Practical Hyper-V socket communication. However, any of them helps me to achieve my goal.
First of all, I've made sure that the connection using Hyper-V sockets is possible. On the guest Linux I loaded hv_sock module and run nc-vsock application which is able to listen on vsocks:
$ sudo modprobe hv_sock
$ nc-vsock -l 1234
On Windows in PowerShell I ran hvc, which utilises Hyper-V sockets and is able to emulate netcat:
hvc nc -t vsock little-helper 1234
and it works. I can see data sent from server to client and vice versa.
Then I wrote a simple application basing on 1 and 2 with slight changes.
I registered my application with the Hyper-V Host's registry as said in 1 and I ran my application. The connection was not established and the connect function returned error 10049.
I've tried to run my application as a administrator and manipulate GUIDs in the source code and on the Hyper-V Host's registry as well. However, nothing helps and application always reports error 10049.
In my opinion in the document are some ambiguity. E.g. it's said that the service id shall be a random GUID. But later on there is a note that the first four octets translate to port in AF_VSOCK address family, and the specific GUID is presented for this purpose.
Question is rather simple: what I did wrong or misunderstood. Is it possible to write netcat utilising vsock between Windows and Linux?
Full code:
#include <iostream>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <hvsocket.h>
#include <combaseapi.h>
int main()
{
struct __declspec(uuid("00000000-185c-4e04-985a-4c2eee3e03cc")) VSockTemplate {};
struct __declspec(uuid("2a9fa68e-4add-45cb-85c8-de97fc66d388")) ServerVsockTemplate {};
//----------------------
// Initialize Winsock
WSADATA wsaData;
int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != NO_ERROR) {
wprintf(L"WSAStartup function failed with error: %d\n", iResult);
return 1;
}
//----------------------
// Create a SOCKET for connecting to server
SOCKET ConnectSocket;
ConnectSocket = socket(AF_HYPERV, SOCK_STREAM, HV_PROTOCOL_RAW);
if (ConnectSocket == INVALID_SOCKET) {
wprintf(L"socket function failed with error: %ld\n", WSAGetLastError());
WSACleanup();
return 1;
}
//----------------------
// The sockaddr_in structure specifies the address family,
// IP address, and port of the server to be connected to.
SOCKADDR_HV clientService;
clientService.Family = AF_HYPERV;
clientService.VmId = __uuidof(ServerVsockTemplate);
clientService.ServiceId = __uuidof(VSockTemplate);
clientService.ServiceId.Data1 = 1234;
//----------------------
// Connect to server.
iResult = connect(ConnectSocket, (SOCKADDR*)&clientService, sizeof(clientService));
if (iResult == SOCKET_ERROR) {
wprintf(L"connect function failed with error: %ld\n", WSAGetLastError());
iResult = closesocket(ConnectSocket);
if (iResult == SOCKET_ERROR)
wprintf(L"closesocket function failed with error: %ld\n", WSAGetLastError());
WSACleanup();
return 1;
}
wprintf(L"Connected to server.\n");
iResult = closesocket(ConnectSocket);
if (iResult == SOCKET_ERROR) {
wprintf(L"closesocket function failed with error: %ld\n", WSAGetLastError());
WSACleanup();
return 1;
}
WSACleanup();
return 0;
}
For whoever is not very familiar with Hyper-V and does not want to spend 2 hours debugging, like I did, a few points:
Ensure that the hv_sock kernel module is enabled on the guest, I used Ubuntu Server 20.04, which does not have this enabled by default.
lsmod | grep hv_sock
If it's not there you need to add it and reboot:
sudo sh -c 'echo "hv_sock" > /etc/modules-load.d/hv_sock.conf'
sudo reboot
You need to register a new application with Hyper-V Host's registry, but the docs are misleading, as the random GUID is only needed with a Windows guest, for Linux guests the GUID needs to be in a very specific format, as described by HV_GUID_VSOCK_TEMPLATE, meaning <port>-facb-11e6-bd58-64006a7986d3
So for port 5001 the registry key should be 00001389-facb-11e6-bd58-64006a7986d3 (1389 is 5001 in hex)
You can do that easily from powershell as described in the Register a new application section
$service = New-Item -Path "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Virtualization\GuestCommunicationServices" -Name "00001389-facb-11e6-bd58-64006a7986d3"
$service.SetValue("ElementName", "HV Socket Demo")
You can find some simple code samples here, win_server.c for the Windows host and wsl_client.c for the Linux guest.
What is the ServerVsockTemplate GUID you have there? I'm pretty sure that's supposed to be the GUID of a running VM, e.g., (Get-VM -Name $VMName).Id, so it'd be hard to hard-code into your source. If that's the GUID you generated per 'Register a new application', that'll be the problem.
The docs aren't clear, but I have the strong suspicion that 'Register a new application' part is only for when you're listening on Windows for incoming connections from other Windows VMs, or when writing a Linux device driver that talks to a service on the host. It might also be to allow a VM to offer services to other VMs, but I would assume not.
Edit: Quick Testing VSOCK (Hyper-V) Support in X410 says you need to make the registry keys for the vsock GUIDs as well, to receive connections from the vm.
In Linux userspace, you only have access to vsock; the other services are managed by drivers under Linux.
There's a clearer explanation of the vsock workflow in the Linux source for the Hyper-V vsock implementation.
I assume it's possible to use VSock between a Windows VM and the host as well, of course.
Edit, because I actually went and tested this.
Two mistakes in the code, on top of the ServerVsockTemplate GUID needing to be the GUID of the target VM.
The VSockTemplate GUID is wrong. I don't know where that came from, but there's a constant HV_GUID_VSOCK_TEMPLATE in <hvsocket.h> anyway, which matches the one on the Microsoft Docs site: 00000000-facb-11e6-bd58-64006a7986d3
It turns out, you need to zero the Reserved member of the SOCKADDR_HV, or it'll fail. Traditionally, one would use memset to zero a new sockaddr_* structure, but in this case, we can take the easy path.
So to make this work, change the SOCKADDR_HV creation code to the following:
// The sockaddr_in structure specifies the address family,
// IP address, and port of the server to be connected to.
SOCKADDR_HV clientService;
clientService.Family = AF_HYPERV;
clientService.Reserved = 0;
clientService.VmId = __uuidof(ServerVsockTemplate);
clientService.ServiceId = HV_GUID_VSOCK_TEMPLATE;
clientService.ServiceId.Data1 = 1234;
Then you delete VSockTemplate, and make sure ServerVsockTemplate is the GUID of the VM or Micro-VM where you're running nc-vsock.
I actually tested this with the WSL2 micro-VM, for which the VM ID comes from hcsdiag list rather than Get-VM, but I was able to connect to nc-vsock inside my WSL2 session using the source here, modified as I have described.
I have previously paired with a Bluetooth device that supports RFCOMM.
When my app is opened I continuously try to connect to the device by opening the RFCOMM. This way my app automatically connects when the device comes in range.
deviceInfoCollection = await DeviceInformation.FindAllAsync(RfcommDeviceService.GetDeviceSelector(RfcommServiceId.SerialPort));
LogData(String.Format("Number of mldp devices is {0}", deviceInfoCollection.Count));
foreach (DeviceInformation deviceInfo in deviceInfoCollection)
{
LogData(String.Format("ID:{0}, NAME:{1}", deviceInfo.Id, deviceInfo.Name));
}
Then run this on a timer:
try
{
// The first time this method is invoked by a store app, it should be called
// from a UI thread in order to display the consent prompt
// https://msdn.microsoft.com/en-us/windows.devices.bluetooth.rfcomm.rfcommdeviceservice.fromidasync
RfcommDeviceService rfcommService = await RfcommDeviceService.FromIdAsync(deviceInfo.Id);
LogData(String.Format("ID:{0}, NAME:{1}", deviceInfo.Id, deviceInfo.Name));
}
catch (Exception)
{
LogData(String.Format("Can not request rfcomm service from device ID:{0}, NAME:{1}", deviceInfo.Id, deviceInfo.Name));
}
Is there any way to query when the device is in range , rather than trying to connect? I would prefer to only attempt connection when the device is in range.
For RFCOMM (BT2.0, BT2.1) you can run a device enumeration periodically, see also Get bluetooth devices in range
However your actual implementation with a connection attempt may work a little better.
For Bluetooth 4.0, you can listen to the advertisements of the BT module, see also https://github.com/Microsoft/Windows-universal-samples/tree/master/Samples/BluetoothAdvertisement
If you're talking to an embedded device (e.g. some robot, or homebrew appliances using RFCOMM) I am afraid there is no better solution than what you're doing.
If you're taking to a phone (which supports both BT4.0 and BT2.1) you can use the BT4 advertisements to signal the proximity of the device, then connect via RFCOMM.
I am trying to stream Audio to a bluetooth device in-code in C#. I've picked up the 32feet.net library to help with this. I am able to get a bluetooth speaker paired just fine, and then I use the code below to connect to the device.
globalClient.BeginConnect(device.DeviceAddress, BluetoothService.SerialPort, new AsyncCallback(BluetoothConnectedAsyncHandler), device);
Async Callback method:
private void BluetoothConnectedAsyncHandler(IAsyncResult result)
{
BluetoothDeviceInfo connectedDevice = (BluetoothDeviceInfo)result.AsyncState;
globalClient.EndConnect(result);
if (result.IsCompleted)
{
NetworkStream btStream = globalClient.GetStream();
}
}
This all works well, but when I try to set the service from BluetoothService.SerialPort to BluetoothService.AudioSource, then I receive a SocketException on the "globalClient.EndConnect(result);" line saying "A socket operation failed because the destination host was down". See screenshot:
I've also tried to throw data at the speaker through the NetworkStream when it is setup with BluetoothService.SerialPort, but it doesn't play anything - no noise or static.
My running hypothesis is that this can't be done easily with 32feet.net, and I would have to code up the a2dp spec in code. I think the 32feet.net library is used so that I can tell the Operating System to use the speaker as an output device, rather than control audio output in-code as a supported feature.
Please help! Has anyone done this?
Would it even work if I sent an a2dp compliant stream to the device over the BluetoothService.SerialPort connection?
A2DP spec: https://www.bluetooth.org/docman/handlers/DownloadDoc.ashx?doc_id=8236
Thanks for any help!
Update:
This isn't possible within the 32feet.net library, you can only set the device up to talk the the Microsoft audio service using the setService method call in 32feet.net
www.nudoq.org/#!/Packages/32feet.NET/InTheHand.Net.Personal/MicrosoftSdpService/M/SetService
This MS service manages the A2DP output to the device. There is no way to directly output audio from code into the Bluetooth Device using this library in C#.
I wanted to use Usage default app to determine how much data my own app send when in roaming mode.
I was very surprised to see that my device sent about 500 Mo. Then I realised that other apps on my phone should have used the network also.
So my question is: how can I enable roaming for just my app and prevent network access for everything else (updates, agenda, mail, ...)?
I run Firefox-OS 2.0 on a ZTE-Open device.
No, this is not possible.
The Data Usage App performs a test like this using the with the Network Stats API:
var end = new Date();
var start = new Date();
// Returns a mozNetworkStats object
var test = navigator.mozNetworkStats.getSamples('mobile', start, end);
console.log(test);
But this test will return a sample of all device connections, not only yours. The simplest solution is to measure the traffic in your Network Monitor.
However, if you want to reduce the amount of mobile traffic for your application, you can restrict all connections to specific connection types (like wifi). Just listen to the typechange event of the NetworkInformation.connection API.
In your WebIDE console (Firefox OS 2.0):
navigator.connection
NetworkInformation { type: "wifi", ontypechange: null }
or
navigator.connection
NetworkInformation { type: "cellular", ontypechange: null }
Please notice, that Firefox OS <=1.5 will never show you a cellular type of connection (it will return none if not wifi).
Anybody knows what changes are necessary for a server to work with xinetd ?
The server being a .NET mailserver that runs on Linux.
See the bottom of this post for reference:
Lumisoft Mailserver Forum Post
Note: xinetd, not mono-service. [x]inetd is an internet superserver.
A superserver starts a server service on demand.
(As opposed to the server service running continuously, which is what mono-service does)
An inetd service runs differently from a standalone server. inetd services read stdin and write to stdout, letting inetd handle the gory details of TCP/IP, rather than keeping track of their own sockets. If you want to make a server run under inetd, it'll have to do the same.
The following program runs just fine under xinetd on my machine:
#include <iostream>
#include <string>
using namespace std; // yeah, i'm lazy.
int main()
{
string name;
cout << "What's your name? " << flush;
cin >> name;
cout << "Hi, " << name << "!" << endl;
}
Note i'm not at all worried about sockets -- xinetd arranges things so that the service can read standard input and write to standard output. You just write your app like you'd be running it on the console, for the most part. The socket details are specified in the config file for the service. (Note, you might be able to get/set details about the socket using stdin/stdout, which may be the actual socket -- i'm not sure -- but you really should leave that stuff up to inetd.)
An inetd services are really great for one off apps that need to take in data and act with some degree of interaction with the user. IT works over tcp/udp by piping the data viva a socket from (x)inetd to std{in,out,err}. inetd apps also works well with tcpwrappers to inhance security though system policy files and ACL.
So yes you would write your app like its a console app since in reality it is a console app. Just think of inetd as a transparent reverse proxy from the network to your app's inputs.
A Word of advice, write your code to handle the process signals correctly and if you need to interact with another process on the system use unix sockets/fifo for that.
Also, don't try to write an app that streams a lot of data all at once or needs a lot of connections. Scalability is an issue as inetd becomes a bottle neck, this is why Apache and Sendmail dropped support for inetd and sit as mono apps instead. HTTP fits this role better and a fastcgi (or insert favorite framework) script with nginx works best for that use case.
A good example for an inetd would be:
lock = Mutex.new
trap :HUP { #log the connection and cleanup }
trap :USR1 { lock.synchronize do #stuff; end }
trap :TERM { #clean up }
trap :KILL { #clean up and die with error codes }
puts "App name - version"
loop do
('%s> ' % Console.prompt).display
input = gets.chomp
command, *params = input.split /\s/
case command
when /\Ahelp\z/i
puts App.help_text
when /\Ado\z/i
Action.perform *params
when /\Aquit\z/i
exit
else
puts 'Invalid command'
end
end
exit
Edit your /etc/services to include your app like this:
myapp port#/proto
and add your app to /etc/inetd.conf (or xinetd.d) like this:
myapp stream tcp6 nowait myappuser /path/to/myapp myapp -arg_flags