Hesham/wintun
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Better ctx management

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Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2019-03-27 17:16:35 +01:00
parent 51f9f59ea9
commit 03a45fb768
1 changed files with 14 additions and 6 deletions
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20
wintun.c
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@ -102,6 +102,7 @@ static NDIS_HANDLE NdisMiniportDriverHandle = NULL;
#define InterlockedGet(val) (InterlockedAdd((val), 0)) #define InterlockedGet(val) (InterlockedAdd((val), 0))
#define InterlockedGet64(val) (InterlockedAdd64((val), 0)) #define InterlockedGet64(val) (InterlockedAdd64((val), 0))
#define InterlockedGetPointer(val) (InterlockedCompareExchangePointer((val), NULL, NULL))
#define InterlockedSubtract(val, n) (InterlockedAdd((val), -(LONG)(n))) #define InterlockedSubtract(val, n) (InterlockedAdd((val), -(LONG)(n)))
#define InterlockedSubtract64(val, n) (InterlockedAdd64((val), -(LONG64)(n))) #define InterlockedSubtract64(val, n) (InterlockedAdd64((val), -(LONG64)(n)))
#define TunPacketAlign(size) (((UINT)(size) + (UINT)(TUN_EXCH_ALIGNMENT - 1)) & ~(UINT)(TUN_EXCH_ALIGNMENT - 1)) #define TunPacketAlign(size) (((UINT)(size) + (UINT)(TUN_EXCH_ALIGNMENT - 1)) & ~(UINT)(TUN_EXCH_ALIGNMENT - 1))
@ -139,11 +140,18 @@ static void TunIndicateStatus(_In_ TUN_CTX *ctx)
NdisMIndicateStatusEx(ctx->MiniportAdapterHandle, &t); NdisMIndicateStatusEx(ctx->MiniportAdapterHandle, &t);
} }
_IRQL_requires_max_(HIGH_LEVEL)
static TUN_CTX * volatile *TunGetContextPointer(_In_ DEVICE_OBJECT *DeviceObject)
{
return (TUN_CTX * volatile *)NdisGetDeviceReservedExtension(DeviceObject);
}
_IRQL_requires_max_(HIGH_LEVEL) _IRQL_requires_max_(HIGH_LEVEL)
static TUN_CTX *TunGetContext(_In_ DEVICE_OBJECT *DeviceObject) static TUN_CTX *TunGetContext(_In_ DEVICE_OBJECT *DeviceObject)
{ {
volatile TUN_CTX **control_device_extension = (volatile TUN_CTX **)NdisGetDeviceReservedExtension(DeviceObject); TUN_CTX * volatile * ctx = TunGetContextPointer(DeviceObject);
return control_device_extension ? (TUN_CTX*)*control_device_extension : NULL; return ctx ? InterlockedGetPointer(ctx) : NULL;
} }
_IRQL_requires_max_(DISPATCH_LEVEL) _IRQL_requires_max_(DISPATCH_LEVEL)
@ -1081,12 +1089,12 @@ static NDIS_STATUS TunInitializeEx(NDIS_HANDLE MiniportAdapterHandle, NDIS_HANDL
ctx->Device.Object->Flags &= ~DO_BUFFERED_IO; ctx->Device.Object->Flags &= ~DO_BUFFERED_IO;
ctx->Device.Object->Flags |= DO_DIRECT_IO; ctx->Device.Object->Flags |= DO_DIRECT_IO;
volatile TUN_CTX **control_device_extension = (volatile TUN_CTX **)NdisGetDeviceReservedExtension(ctx->Device.Object); TUN_CTX * volatile * control_device_extension = TunGetContextPointer(ctx->Device.Object);
if (!control_device_extension) { if (!control_device_extension) {
status = NDIS_STATUS_FAILURE; status = NDIS_STATUS_FAILURE;
goto cleanup_NdisDeregisterDeviceEx; goto cleanup_NdisDeregisterDeviceEx;
} }
*control_device_extension = ctx; InterlockedExchangePointer(control_device_extension, ctx);
ctx->State = TUN_STATE_PAUSED; ctx->State = TUN_STATE_PAUSED;
return NDIS_STATUS_SUCCESS; return NDIS_STATUS_SUCCESS;
@ -1119,9 +1127,9 @@ static void TunHaltEx(NDIS_HANDLE MiniportAdapterContext, NDIS_HALT_ACTION HaltA
ASSERT(!InterlockedGet64(&ctx->Device.RefCount)); ASSERT(!InterlockedGet64(&ctx->Device.RefCount));
/* Reset adapter context in device object, as Windows keeps calling dispatch handlers even after NdisDeregisterDeviceEx(). */ /* Reset adapter context in device object, as Windows keeps calling dispatch handlers even after NdisDeregisterDeviceEx(). */
volatile TUN_CTX **control_device_extension = (volatile TUN_CTX **)NdisGetDeviceReservedExtension(ctx->Device.Object); TUN_CTX * volatile * control_device_extension = TunGetContextPointer(ctx->Device.Object);
if (control_device_extension) if (control_device_extension)
*control_device_extension = NULL; InterlockedExchangePointer(control_device_extension, NULL);
/* Release resources. */ /* Release resources. */
NdisDeregisterDeviceEx(ctx->Device.Handle); NdisDeregisterDeviceEx(ctx->Device.Handle);