I have tried extending IOUserNetworkEthernet and calling RegisterEthernetInterface(). This works perfectly for one ethernet interface, though the driver crashes when RegisterEthernetInterface is called a second time (doesn't return an error code). I have tried registering with separate queues.
Another approach was extending IOUserClient instead, and calling IOService::Create to create child IOUserNetworkEthernet instances. Everything about this approach works (the children appear within ioreg). However, once I call RegisterEthernetInterface on just one of the children, macOS crashes.
How would I go about creating a dext with multiple ethernet interfaces? Have I been approaching it the right way?
Appreciate any help.
I haven't yet implemented an ethernet dext myself, but based on my experience with using DriverKit for other types of drivers and knowing its design goals, I have an idea what the solution might be.
First off, let's clarify: you're implementing either a virtual ethernet device, or you're building a driver for hardware that unites multiple independent ports in one physical device. In the former case (I'm guessing this is what you're doing based on your IOUserClient comment), your driver will be matching IOUserResources and you create the ethernet driver instance when you receive the corresponding message from your user space component.
Now, DriverKit design: DriverKit is built around a goal of keeping the driver instance for each device in its own separate process. Sort of circling back to the microkernel idea. Specifically, this means that multiple devices that use the same driver will each create an independent instance of that driver in its own process. This very likely means that NetworkingDriverKit was never designed to support more than one instance of IOUserNetworkEthernet, because they are seen as separate devices. Hence the crashes.
OK, what do we do about it? Use DriverKit the way it was intended. Put each virtual ethernet adapter in its own driver instance. This gets a bit tricky. I think this should work:
Your dext has a "control" instance. This is the thing that matches IOUserResources. It's a simple IOService class which listens for the signal (presumably IOUserClient) to create or destroy a virtual ethernet device. When creating a virtual ethernet device, you need that to run in its own driver instance though. (For an actual device with multiple ports, this would match the USB/PCI device nub, manage bus communication with the device, and enumerate the ports.)
Instead of creating an instance of a IOUserNetworkEthernet subclass, create an instance of a "nub" class and attach it to your central control class instance. Call RegisterService() in its startup code, so it's considered for IOKit matching.
Set up a second IOKit matching dictionary in your Info.plist, which matches your new "nub" object. Here, use your IOUserNetworkEthernet-derived class to "drive" the nub. Once the virtual ethernet device is ready to use, call RegisterEthernetInterface().
2 extra things to note:
The virtual device will run in a separate process from the control object, so they can only communicate via DriverKit inter-process calls, i.e. user clients. Hopefully, they don't really need to communicate much though, and the control client can pass all the information required via properties on the nub. If you're implementing support for multi-port hardware, you probably won't be able to avoid this part though.
Your user space component (app, daemon) will need to open a new communication channel with the virtual device, so you'll probably need to implement user client support there too.
I'm not sure how you'd go about shutting down an individual virtual ethernet device, you could try calling Terminate() on either it or the nub it's matched on and see what happens.
Related
I am writing a driverkit extension whose goal is to block some categories of USB devices, such as flash drives. The driver should block (match to) any device of the relevant device classes, except those, which are whitelisted (based on their vendor and product ID). The whitelist can be set dynamically by user of the application.
The question is, how to pass these data to the driver as reading from a file or something like Windows registry is not available in the DriverKit. The tricky part is that the driver requires the whitelist data before the device is matched.
From what I understood, rejection of device is possible by returning an error from Start() method and returning from it prematurely. I got an idea to send the data while the driver is running this function, however this is not possible as the communication via IOUserClass is not available until the Start method returns.
Is this somehow doable?
As far as I'm aware, communicating with user space apps from the initial Start() method is not possible from DriverKit extensions. As you say, IOUserClients are the mechanism to use for user space communication, and those aren't available until the service is started and registered. You can have your driver match IOResources/IOUserResources so it is always loaded, but each matched service starts up an independed process of your dext, and I'm not aware of a way to directly communicate between these instances.
If I understand you correctly, you're trying to block other drivers from acquiring the device. I don't think the solution you have in mind will help you with this. If you return success from Start(), your dext will drive the device. If you return failure, no driver is loaded for the device, because matching has already concluded. So other drivers would never get a chance anyway, regardless of whether the device is on your allow-list or deny-list.
It's new in DriverKit 21 (i.e. macOS Monterey), and I've not had a chance to try it yet, but there is an API for reading files, OSMappedFile. I would imagine that the DriverKit sandbox will have something to say about which files a dext can open, but this seems like an avenue worth exploring whether you can open configuration files this way.
Note that none of this will help you during early boot, as your dext will never be considered for matching at that time. And you may not be able to get required entitlements from Apple to build a dext which matches USB device classes rather than specific product/vendor ID patterns. (Apologies for repeating myself, but other users may come across this answer and not be aware of this issue.)
From a general standpoint, I am trying to figure out how to access a platform device from userspace. To be more specific, I have a EMIF controller on and SoC of which I have added to my device tree and I believe it is correctly bound to a pre-written EMIF platform device driver. Now I am trying to figure out how I can access this EMIF device from a userspace application. I have come accross a couple different topics that seem to have some connection to this issue but I cannot quite find out how they relate.
1) As I read it seems like most I/O is done through the use of device nodes which are created by mknod(), do I need to create a device node in order to access this device?
2) I have read a couple threads that talk about writting a Kernel module (Character?, Block?) that can interface with both userspace and the platform device driver, and use it as an intermediary.
3) I have read about the possibility of using mmap() to map the memory of my platform device into my virtual memory space. Is this possible?
4) It seems that when the EMIF driver is instantiated, it calls the probe() fucntion. What functions would a userpace application call in the driver?
It's not completely clear what you're needing to do (and I should caveat that I have no experience with EMIF or with "platform devices" specifically), but here's some overview to help you get started:
Yes, the usual way of providing access to a device is via a device node. Usually this access is provided by a character device driver unless there's some more specific way of providing it. Most of the time if an application is talking "directly" to your driver, it's a character device. Most other types of devices are used in interfacing with other kernel subsystems: for example, a block device is typically used to provide access from a file system driver (say) to an underlying disk drive; a network driver provides access to the network from the in-kernel TCP/IP stack, etc.
There are several char device methods or entry points that can be supported by your driver, but the most common are "read" (i.e. if a user-space program opens your device and does a read(2) from it), "write" (analogous for write(2)) and "ioctl" (often used for configuration/administrative tasks that don't fall naturally into either a read or write). Note that mknod(2) only creates the user-space side of the device. There needs to be a corresponding device driver in the kernel (the "major device number" given in the mknod call links the user-space node with the driver).
For actually creating the device node in the file system, this can be automated (i.e. the node will automatically show up in /dev) if you call the right kernel functions while setting up your device. There's a special daemon that gets notifications from the kernel and responds by executing the mknod(2) system call.
A kernel module is merely a dynamically loadable way of creating a driver or other kernel extension. It can create a character, block or network device (et al.), but then so can a statically linked module. There are some differences in capability mostly because not all kernel functions you might want to use are "exported" to (i.e. visible to) dynamically loaded modules.
It's possible to support mapping of the device memory into user virtual memory space. This would be implemented by yet another driver entry point (mmap). See struct file_operations for all the entry points a char driver can support.
This is pretty much up to you: it depends on what the application needs to be able to do. There are many drivers in the kernel that provide no direct function to user-space, only to other kernel code. As to "probe", there are many probe functions defined in various interfaces. In most cases, these are called by the kernel (or perhaps by a 'higher level "class" driver') to allow the specific driver to discover, identify and "claim" individual devices. They (probe functions) don't usually have anything directly to do with providing access from user-space but I might well be missing something in a particular interface.
You need to create a device node in order to access the device.
The probe function is called when the driver finds a matching device.
For information on platform device API, the following articles could be useful.
The platform device API
Platform devices and device trees
I'm trying to put together a cross-platform application that interfaces with Insteon automation hardware. In the .Net based examples I've found, the System.IO.Ports.SerialPort class is used to read data from both an RS-232 Serial Port based device and a USB Serial Modem. On a Windows platform, the Serial Modems generally get mapped to a virtual COM Port and it's not to difficult to run down a list, passing in new COM addresses and attempting to figure out which one the USB or Serial device is attached to.
Unfortunately on the Mac, I'm totally out of my element. MonoMac allows me to program in a more comfortable language, but something as low level as talking to hardware is a bit beyond my reach. My initialization code is as follows:
private void OpenSerialConnection(string comPort)
{
_serialPort = new System.IO.Ports.SerialPort("/dev/ttys1", 19200, System.IO.Ports.Parity.None, 8, System.IO.Ports.StopBits.One);
_serialPort.Encoding = System.Text.Encoding.Default;
_serialPort.WriteTimeout = 1000;
_serialPort.DataReceived += OnDataReceived;
_serialPort.Open();
}
The "/dev/ttsy1" value which is in place of where the "comPort" variable would go is part of some examples I found that suggest the address might be in the form of /dev/ttys*. After some searching, I discovered that a usb device would likely register as "/dev/tty.usbserial*", but I'm wondering if there's a more elegant way if detecting what this value is that I can leverage in Mono rather than instructing a user to go into Terminal and type "ls /dev/tty.*" and type it themselves?
I don't have any personal experience with Mono on the Mac, but I think it's possible to include and use Objective-C classes in your Mono projects. Assuming that's the case, take a look at ORSSerialPort. ORSSerialPortManager's -availablePorts method will give you an array of all the serial ports available on the system. You can also sign up to receive notifications when ports are added/removed, and the library also makes it easy to open a port, configure it, and send and receive data.
Without something like this, you have to use IOKit to discover ports on the system, and the POSIX APIs for opening, configuring, reading from, and writing to serial ports. IOKit and the POSIX serial port APIs are low(ish) level C APIs.
I am new to Linux and I need to write a USB driver for a device with 2 interfaces. One interface is HID class (3/0/0) with one interrupt in endpoint and a report descriptor. The other interface is vendor defined with 3 bulk endpoints. In my usb_device_id table I have a USB_DEVICE entry with the VID and PID.
When I plug in the device, my xxx_probe function is called for the vendor defined interface but not for the HID interface. Instead, it appears that a built-in driver called 'generic-usb' is taking control of the HID interface.
Is there a way to ensure that my driver probe function is called first?
Why doesn't Linux make multiple passes looking for a more specific driver first (like Windows does)?
Alternatively, can the 'generic-usb' driver be used to receive data on the interrupt endpoint and to set reports and features on the control pipe?
It appears that libusb-1.0.8 allows an application to take control of interfaces on an attached device without the need of a custom driver. So far it appears to provide all the support that I need.
In my computer, there are two network adapters, connecting to different subnet. As below:
adapter A: 10.20.30.201
adapter B: 10.20.31.201
I want to make all outgoing data of a special process (for example Process A) through adapter A. That is I want to make adapter A as the process's default route.
I know, I can modify route table for some special destination, But what I want to do here is very different. Process A may communicate with many different IP and I don't know in advance.
Winsock2 provides LSP as a way to lay a dll in TCP/IP stack. I'm not familiar with LSP and don't know whether LSP can do what I want to do.
Can anybody give me some suggestion, Thanks.
A quick background on LSP:
An application, which uses Winsock2 API, calls a combination of WSA-prefix functions, eg WSAConnect, WSASocket, WSASend, WSARecv, etc.
If an application still use old winsock functions, these functions are mapped to Winsock2 behind the scene anyway. For instances: send() is mapped to WSASend(), recv() to WSARecv(), etc
WSA-prefix functions will internally call their corresponding WSP-prefix functions provided by LSP. For instances WSASend() calls WSPSend(), WSASocket() call WSPSocket(), etc. In short, WSAWhateverFunction() will calls WSPWhateverFunction(). Their parameters/returns are also the same (Not quite, but kind of).
LSP is a dll with these WSP-prefix functions implemented, eg. modify outbound/inbound traffic, filtering, etc. However an LSP is still a userspace dll. It's as limited as other userspace programs, and has no higher privilege than its host application, eg internet browsers. It has access to same set of system functions that is available to other programs, eg. winsock etc.
Conclusion is if your program can direct out-coming traffic to specific NIC, LSP can do it too. If it can't, neither can LSP. LSP therefore is irrelevant to your problem.