Hesham/wintun
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Use explicit running boolean and use set instead of exchange

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Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2019-07-23 13:19:37 +00:00
parent 999a6744db
commit 18cfd522aa
1 changed files with 31 additions and 24 deletions
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55
wintun.c
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@ -106,14 +106,9 @@ typedef struct _TUN_REGISTER_RINGS
/* Force close all open handles to allow for updating. */
#define TUN_IOCTL_FORCE_CLOSE_HANDLES CTL_CODE(51820, 0x971, METHOD_NEITHER, FILE_READ_DATA | FILE_WRITE_DATA)
typedef enum _TUN_FLAGS
{
TUN_FLAGS_RUNNING = 1 << 0, /* Toggles between paused and running state */
} TUN_FLAGS;
typedef struct _TUN_CTX
{
volatile LONG Flags;
volatile LONG Running;
/* Used like RCU. When we're making use of rings, we take a shared lock. When we want to register or release the
* rings and toggle the state, we take an exclusive lock before toggling the atomic and then releasing. It's similar
@ -168,10 +163,22 @@ static DRIVER_DISPATCH *NdisDispatchDeviceControl, *NdisDispatchClose;
static ERESOURCE TunDispatchCtxGuard;
static SECURITY_DESCRIPTOR *TunDispatchSecurityDescriptor;
static __forceinline ULONG
InterlockedExchangeU(_Inout_ _Interlocked_operand_ ULONG volatile *Target, _In_ ULONG Value)
static __forceinline VOID
InterlockedSet(_Inout_ _Interlocked_operand_ LONG volatile *Target, _In_ LONG Value)
{
return (ULONG)InterlockedExchange((LONG volatile *)Target, Value);
*Target = Value;
}
static __forceinline VOID
InterlockedSetU(_Inout_ _Interlocked_operand_ ULONG volatile *Target, _In_ ULONG Value)
{
*Target = Value;
}
static __forceinline VOID
InterlockedSetPointer(_Inout_ _Interlocked_operand_ VOID * volatile *Target, _In_opt_ VOID *Value)
{
*Target = Value;
}
static __forceinline LONG
@ -286,7 +293,7 @@ TunSendNetBufferLists(
KIRQL Irql = ExAcquireSpinLockShared(&Ctx->TransitionLock);
NDIS_STATUS Status;
if ((Status = NDIS_STATUS_PAUSED, !(InterlockedGet(&Ctx->Flags) & TUN_FLAGS_RUNNING)) ||
if ((Status = NDIS_STATUS_PAUSED, !InterlockedGet(&Ctx->Running)) ||
(Status = NDIS_STATUS_MEDIA_DISCONNECTED, KeReadStateEvent(&Ctx->Device.Disconnected)))
goto skipNbl;
@ -357,7 +364,7 @@ TunSendNetBufferLists(
{
NET_BUFFER_LIST *CompletedNbl = Ctx->Device.Send.ActiveNbls.Head;
Ctx->Device.Send.ActiveNbls.Head = NET_BUFFER_LIST_NEXT_NBL(CompletedNbl);
InterlockedExchangeU(&Ring->Tail, TunNblGetOffset(CompletedNbl));
InterlockedSetU(&Ring->Tail, TunNblGetOffset(CompletedNbl));
KeSetEvent(Ctx->Device.Send.TailMoved, IO_NETWORK_INCREMENT, FALSE);
NET_BUFFER_LIST_NEXT_NBL(CompletedNbl) = NULL;
NdisMSendNetBufferListsComplete(
@ -440,7 +447,7 @@ TunReturnNetBufferLists(NDIS_HANDLE MiniportAdapterContext, PNET_BUFFER_LIST Net
}
Ctx->Device.Receive.ActiveNbls.Head = NET_BUFFER_LIST_NEXT_NBL_EX(CompletedNbl);
KeReleaseInStackQueuedSpinLock(&LockHandle);
InterlockedExchangeU(&Ring->Head, TunNblGetOffset(CompletedNbl));
InterlockedSetU(&Ring->Head, TunNblGetOffset(CompletedNbl));
NdisFreeNetBufferList(CompletedNbl);
}
@ -496,16 +503,16 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
}
if (RingHead == RingTail)
{
InterlockedExchange(&Ring->Alertable, TRUE);
InterlockedSet(&Ring->Alertable, TRUE);
RingTail = InterlockedGetU(&Ring->Tail);
if (RingHead == RingTail)
{
KeWaitForMultipleObjects(
RTL_NUMBER_OF(Events), Events, WaitAny, Executive, KernelMode, FALSE, NULL, NULL);
InterlockedExchange(&Ring->Alertable, FALSE);
InterlockedSet(&Ring->Alertable, FALSE);
continue;
}
InterlockedExchange(&Ring->Alertable, FALSE);
InterlockedSet(&Ring->Alertable, FALSE);
KeClearEvent(Ctx->Device.Receive.TailMoved);
}
}
@ -563,7 +570,7 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
KeReleaseInStackQueuedSpinLock(&LockHandle);
KIRQL Irql = ExAcquireSpinLockShared(&Ctx->TransitionLock);
if (!(InterlockedGet(&Ctx->Flags) & TUN_FLAGS_RUNNING))
if (!InterlockedGet(&Ctx->Running))
goto skipNbl;
if (!NT_SUCCESS(IoAcquireRemoveLock(&Ctx->Device.Receive.ActiveNbls.RemoveLock, Nbl)))
@ -590,7 +597,7 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
if (NT_SUCCESS(IoAcquireRemoveLock(&Ctx->Device.Receive.ActiveNbls.RemoveLock, NULL)))
IoReleaseRemoveLockAndWait(&Ctx->Device.Receive.ActiveNbls.RemoveLock, NULL);
cleanup:
InterlockedExchangeU(&Ring->Head, MAXULONG);
InterlockedSetU(&Ring->Head, MAXULONG);
}
#define IS_POW2(x) ((x) && !((x) & ((x)-1)))
@ -606,7 +613,7 @@ TunRegisterBuffers(_Inout_ TUN_CTX *Ctx, _Inout_ IRP *Irp)
if (InterlockedCompareExchangePointer(&Ctx->Device.Owner, Stack->FileObject, NULL) != NULL)
return STATUS_ALREADY_INITIALIZED;
ASSERT(InterlockedGet(&Ctx->Flags) & TUN_FLAGS_RUNNING);
ASSERT(InterlockedGet(&Ctx->Running));
TUN_REGISTER_RINGS *Rrb = Irp->AssociatedIrp.SystemBuffer;
if (Status = STATUS_INVALID_PARAMETER, Stack->Parameters.DeviceIoControl.InputBufferLength != sizeof(*Rrb))
@ -712,7 +719,7 @@ cleanupSendMdl:
cleanupSendTailMoved:
ObDereferenceObject(Ctx->Device.Send.TailMoved);
cleanupResetOwner:
InterlockedExchangePointer(&Ctx->Device.Owner, NULL);
InterlockedSetPointer(&Ctx->Device.Owner, NULL);
return Status;
}
@ -739,7 +746,7 @@ TunUnregisterBuffers(_Inout_ TUN_CTX *Ctx, _In_ FILE_OBJECT *Owner)
}
ZwClose(Ctx->Device.Receive.Thread);
InterlockedExchangeU(&Ctx->Device.Send.Ring->Tail, MAXULONG);
InterlockedSetU(&Ctx->Device.Send.Ring->Tail, MAXULONG);
KeSetEvent(Ctx->Device.Send.TailMoved, IO_NO_INCREMENT, FALSE);
MmUnlockPages(Ctx->Device.Receive.Mdl);
@ -923,7 +930,7 @@ TunRestart(NDIS_HANDLE MiniportAdapterContext, PNDIS_MINIPORT_RESTART_PARAMETERS
{
TUN_CTX *Ctx = (TUN_CTX *)MiniportAdapterContext;
IoInitializeRemoveLock(&Ctx->Device.Receive.ActiveNbls.RemoveLock, TUN_MEMORY_TAG, 0, 0);
InterlockedOr(&Ctx->Flags, TUN_FLAGS_RUNNING);
InterlockedSet(&Ctx->Running, TRUE);
return NDIS_STATUS_SUCCESS;
}
@ -934,7 +941,7 @@ TunPause(NDIS_HANDLE MiniportAdapterContext, PNDIS_MINIPORT_PAUSE_PARAMETERS Min
{
TUN_CTX *Ctx = (TUN_CTX *)MiniportAdapterContext;
InterlockedAnd(&Ctx->Flags, ~TUN_FLAGS_RUNNING);
InterlockedSet(&Ctx->Running, FALSE);
ExReleaseSpinLockExclusive(
&Ctx->TransitionLock,
ExAcquireSpinLockExclusive(&Ctx->TransitionLock)); /* Ensure above change is visible to all readers. */
@ -1123,9 +1130,9 @@ TunHaltEx(NDIS_HANDLE MiniportAdapterContext, NDIS_HALT_ACTION HaltAction)
ExAcquireSpinLockExclusive(&Ctx->TransitionLock)); /* Ensure above change is visible to all readers. */
NdisFreeNetBufferListPool(Ctx->NblPool);
InterlockedExchangePointer(&Ctx->MiniportAdapterHandle, NULL);
InterlockedSetPointer(&Ctx->MiniportAdapterHandle, NULL);
#pragma warning(suppress : 28175)
InterlockedExchangePointer(&Ctx->FunctionalDeviceObject->Reserved, NULL);
InterlockedSetPointer(&Ctx->FunctionalDeviceObject->Reserved, NULL);
ExAcquireResourceExclusiveLite(&TunDispatchCtxGuard, TRUE); /* Ensure above change is visible to all readers. */
ExReleaseResourceLite(&TunDispatchCtxGuard);
ExFreePoolWithTag(Ctx, TUN_MEMORY_TAG);