The transition lock ensures that TunPause won't drop its last reference
until the shared transition lock is dropped.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
It turns out that waiting for them to come back in the return function
introduces extremely high latency.
We need to eventually stop doing this and move to a proper ring buffer.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Even though we're comparing this with a ptrdiff_t in one place and
adding it to a void* in another place, it's still a length and as such
should be a size_t, which I guess in our weird universe here is a ULONG.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
WHLK 1903 CHAOS tests are reporting lots of issues regarding surprise
removal misbehavior:
WDTF_PNP: INFO : Result: TestSurpriseRemove operation timed out waiting
for IRP_MN_REMOVE_DEVICE..
WDTF_PNP: ERROR : Result: Failed to receive IRP_MN_REMOVE_DEVICE after
receiving IRP_MN_SURPRISE_REMOVAL. Ensure that there are no open
handles or references to the test device (in user mode or in kernel
mode) preventing IRP_MN_REMOVE_DEVICE from being sent. You may need
to terminate any processes or services that may have open user mode
handles to this device. ( 80004005 ).
Signed-off-by: Simon Rozman <simon@rozman.si>
By replacing the NDIS' IRP_MJ_PNP dispatch handler we get the first
chance to clear the NBL queue to make NDIS proceed to TunPause() on
device removal.
This method is simpler than PnP notifications and we are chasing
surprise removal issues in WHLK tests. If this works, I'll hopefully
come back and update this commit message.
Signed-off-by: Simon Rozman <simon@rozman.si>
The Microsoft Documentation is clear:
"The PnP manager can still call the driver's notification callback
routine, but in such calls the file object in the NotificationStructure
is not valid."[1]
Therefore, we must not touch the notification->FileObject in
GUID_TARGET_DEVICE_REMOVE_CANCELLED.
"Because the driver closed the previous registration handle in response
to the query-remove notification, the driver must open a new handle. The
driver must:
1. Remove the old registration with IoUnregisterPlugPlayNotification.
2. Open a new handle to the device.
3. Reregister for notification on the new handle with
IoRegisterPlugPlayNotification."
Therefore, let's do it. Unfortunately, in order to implement this, we
must save the driver object and device symbolic name.
[1](https://docs.microsoft.com/en-us/windows-hardware/drivers/kernel/handling-a-guid-target-device-query-remove-event)
[2](https://docs.microsoft.com/en-us/windows-hardware/drivers/kernel/handling-a-guid-target-device-remove-cancelled-event)
Signed-off-by: Simon Rozman <simon@rozman.si>
As ActiveTransacrionCount is all about counting NBLs in flight (or just
about to push some more NBLs), rename it to a more suitable name.
Signed-off-by: Simon Rozman <simon@rozman.si>
Asserting on 63-bit overflow seems a bit excessive.
While 31-bit overflow is more likely to happen, we should introduce a
real check if we are concerned about it. Rather than using an ASSERT in
Debug configuration run by probably nobody else but me.
Signed-off-by: Simon Rozman <simon@rozman.si>
When we are transitioning to a state that suspends some operations, we
must get an exclusive transition lock to wait for all operations that
have a shared transition lock. And TunHaltEx() is no exception.
Signed-off-by: Simon Rozman <simon@rozman.si>
TunCheckForPause() was inlined and adjusted: it had two calls with two
potential new ones, but each call would have a slightly different
optimal variant: some with ActiveTransactionCount increment, others
without; some with Device.RefCount check, others without... No two
particular use cases were completely identical:
1. TunSendNetBufferLists:
- requires ActiveTransactionCount increment
- requires Device.RefCount > 0 check
- reports NDIS_STATUS in case of rejection
2. IRP_MJ_READ:
- no ActiveTransactionCount increment
- no Device.RefCount > 0 check, as IRP_MJ_READ implies it
- reports NTSTATUS in case of rejection
3. IRP_MJ_WRITE:
- requires ActiveTransactionCount increment
- no Device.RefCount > 0 check, as IRP_MJ_WRITE implies it
- reports NTSTATUS in case of rejection
4. IRP_MJ_CREATE:
- no ActiveTransactionCount increment
- no Device.RefCount > 0 check to allow initial client connection
- reports NTSTATUS in case of rejection, with slightly different
status codes than IRP_MJ_READ and IRP_MJ_WRITE.
TUN_FLAGS_ENABLED was renamed to TUN_FLAGS_RUNNING: enabled/disabled
adapter means initialized&running/paused&halted in Windows world.
Signed-off-by: Simon Rozman <simon@rozman.si>
