/*
 Derived from source code of TrueCrypt 7.1a, which is
 Copyright (c) 2008-2012 TrueCrypt Developers Association and which is governed
 by the TrueCrypt License 3.0.

 Modifications and additions to the original source code (contained in this file) 
 and all other portions of this file are Copyright (c) 2013-2016 IDRIX
 and are governed by the Apache License 2.0 the full text of which is
 contained in the file License.txt included in VeraCrypt binary and source
 code distribution packages.
*/

#ifndef TC_HEADER_DRIVER_ENCRYPTED_IO_QUEUE
#define TC_HEADER_DRIVER_ENCRYPTED_IO_QUEUE

#include "TCdefs.h"
#include "Apidrvr.h"

#if 0
#	define TC_TRACE_IO_QUEUE
#endif

#define TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE (256 * 1024)

#define TC_ENC_IO_QUEUE_PREALLOCATED_ITEM_COUNT 8
#define TC_ENC_IO_QUEUE_PREALLOCATED_IO_REQUEST_COUNT 16


typedef struct EncryptedIoQueueBufferStruct
{
	struct EncryptedIoQueueBufferStruct *NextBuffer;

	void *Address;
	ULONG Size;
	BOOL InUse;

} EncryptedIoQueueBuffer;


typedef struct
{
	PDEVICE_OBJECT DeviceObject;
	
	KMUTEX BufferPoolMutex;
	EncryptedIoQueueBuffer *FirstPoolBuffer;

	CRYPTO_INFO *CryptoInfo;
	
	// File-handle-based IO
	HANDLE HostFileHandle;
	int64 VirtualDeviceLength;
	SECURITY_CLIENT_CONTEXT *SecurityClientContext;

	// Filter device
	BOOL IsFilterDevice;
	PDEVICE_OBJECT LowerDeviceObject;
	int64 EncryptedAreaStart;
	volatile int64 EncryptedAreaEnd;
	volatile BOOL EncryptedAreaEndUpdatePending;
	BOOL RemapEncryptedArea;
	int64 RemappedAreaOffset;
	int64 RemappedAreaDataUnitOffset;
	IO_REMOVE_LOCK RemoveLock;

	// Main tread
	PKTHREAD MainThread;
	LIST_ENTRY MainThreadQueue;
	KSPIN_LOCK MainThreadQueueLock;
	KEVENT MainThreadQueueNotEmptyEvent;

	// IO thread
	PKTHREAD IoThread;
	LIST_ENTRY IoThreadQueue;
	KSPIN_LOCK IoThreadQueueLock;
	KEVENT IoThreadQueueNotEmptyEvent;

	// Completion thread
	PKTHREAD CompletionThread;
	LIST_ENTRY CompletionThreadQueue;
	KSPIN_LOCK CompletionThreadQueueLock;
	KEVENT CompletionThreadQueueNotEmptyEvent;

	// Fragment buffers
	byte *FragmentBufferA;
	byte *FragmentBufferB;
	KEVENT FragmentBufferAFreeEvent;
	KEVENT FragmentBufferBFreeEvent;

	// Read-ahead buffer
	BOOL ReadAheadBufferValid;
	LARGE_INTEGER LastReadOffset;
	ULONG LastReadLength;
	LARGE_INTEGER ReadAheadOffset;
	ULONG ReadAheadLength;
	byte *ReadAheadBuffer;
	LARGE_INTEGER MaxReadAheadOffset;

	LONG OutstandingIoCount;
	KEVENT NoOutstandingIoEvent;
	LONG IoThreadPendingRequestCount;

	KEVENT PoolBufferFreeEvent;

	__int64 TotalBytesRead;
	__int64 TotalBytesWritten;

	volatile BOOL StartPending;
	volatile BOOL ThreadExitRequested;
	
	volatile BOOL Suspended;
	volatile BOOL SuspendPending;
	volatile BOOL StopPending;

	KEVENT QueueResumedEvent;

#ifdef TC_TRACE_IO_QUEUE
	LARGE_INTEGER LastPerformanceCounter;
#endif

}  EncryptedIoQueue;


typedef struct
{
	EncryptedIoQueue *Queue;
	PIRP OriginalIrp;
	BOOL Write;
	ULONG OriginalLength;
	LARGE_INTEGER OriginalOffset;
	NTSTATUS Status;

#ifdef TC_TRACE_IO_QUEUE
	LARGE_INTEGER OriginalIrpOffset;
#endif

} EncryptedIoQueueItem;


typedef struct
{
	EncryptedIoQueueItem *Item;

	BOOL CompleteOriginalIrp;
	LARGE_INTEGER Offset;
	ULONG Length;
	int64 EncryptedOffset;
	ULONG EncryptedLength;
	byte *Data;
	byte *OrigDataBufferFragment;

	LIST_ENTRY ListEntry;
	LIST_ENTRY CompletionListEntry;
} EncryptedIoRequest;


NTSTATUS EncryptedIoQueueAddIrp (EncryptedIoQueue *queue, PIRP irp);
BOOL EncryptedIoQueueIsRunning (EncryptedIoQueue *queue);
BOOL EncryptedIoQueueIsSuspended (EncryptedIoQueue *queue);
NTSTATUS EncryptedIoQueueResumeFromHold (EncryptedIoQueue *queue);
NTSTATUS EncryptedIoQueueStart (EncryptedIoQueue *queue);
NTSTATUS EncryptedIoQueueStop (EncryptedIoQueue *queue);
NTSTATUS EncryptedIoQueueHoldWhenIdle (EncryptedIoQueue *queue, int64 timeout);


#endif // TC_HEADER_DRIVER_ENCRYPTED_IO_QUEUE