/*
 *  TAP-Windows -- A kernel driver to provide virtual tap
 *                 device functionality on Windows.
 *
 *  This code was inspired by the CIPE-Win32 driver by Damion K. Wilson.
 *
 *  This source code is Copyright (C) 2002-2014 OpenVPN Technologies, Inc.,
 *  and is released under the GPL version 2 (see below).
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program (see the file COPYING included with this
 *  distribution); if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

//------------------
// Memory Management
//------------------

PVOID
MemAlloc(__in ULONG p_Size, __in BOOLEAN zero);

VOID MemFree(__in PVOID p_Addr, __in ULONG p_Size);

//======================================================================
// TAP Packet Queue
//======================================================================

typedef struct _TAP_PACKET {
  LIST_ENTRY QueueLink;

#define TAP_PACKET_SIZE(data_size) (sizeof(TAP_PACKET) + (data_size))
#define TP_TUN 0x80000000
#define TP_SIZE_MASK (~TP_TUN)
  ULONG m_SizeFlags;

  // m_Data must be the last struct member
  UCHAR m_Data[];
} TAP_PACKET, *PTAP_PACKET;

#define TAP_PACKET_TAG '6PAT'  // "TAP6"

typedef struct _TAP_PACKET_QUEUE {
  KSPIN_LOCK QueueLock;
  LIST_ENTRY Queue;
  ULONG Count;  // Count of currently queued items
  ULONG MaxCount;
} TAP_PACKET_QUEUE, *PTAP_PACKET_QUEUE;

VOID tapPacketQueueInsertTail(__in PTAP_PACKET_QUEUE TapPacketQueue, __in PTAP_PACKET TapPacket);

// Call with QueueLock held
PTAP_PACKET
tapPacketRemoveHeadLocked(__in PTAP_PACKET_QUEUE TapPacketQueue);

VOID tapPacketQueueInitialize(__in PTAP_PACKET_QUEUE TapPacketQueue);

//----------------------
// Cancel-Safe IRP Queue
//----------------------

typedef struct _TAP_IRP_CSQ {
  IO_CSQ CsqQueue;
  KSPIN_LOCK QueueLock;
  LIST_ENTRY Queue;
  ULONG Count;  // Count of currently queued items
  ULONG MaxCount;
} TAP_IRP_CSQ, *PTAP_IRP_CSQ;

VOID tapIrpCsqInitialize(__in PTAP_IRP_CSQ TapIrpCsq);

VOID tapIrpCsqFlush(__in PTAP_IRP_CSQ TapIrpCsq);
