release/src/router/openvpn/tap-win32/tmp/lock.h

   1 /*
   2  *  TAP-Win32/TAP-Win64 -- A kernel driver to provide virtual tap
   3  *                         device functionality on Windows.
   4  *
   5  *  This code was inspired by the CIPE-Win32 driver by Damion K. Wilson.
   6  *
   7  *  This source code is Copyright (C) 2002-2009 OpenVPN Technologies, Inc.,
   8  *  and is released under the GPL version 2 (see below), however due
   9  *  to the extra costs of supporting Windows Vista, OpenVPN Solutions
  10  *  LLC reserves the right to change the terms of the TAP-Win32/TAP-Win64
  11  *  license for versions 9.1 and higher prior to the official release of
  12  *  OpenVPN 2.1.
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License version 2
  16  *  as published by the Free Software Foundation.
  17  *
  18  *  This program is distributed in the hope that it will be useful,
  19  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  *  GNU General Public License for more details.
  22  *
  23  *  You should have received a copy of the GNU General Public License
  24  *  along with this program (see the file COPYING included with this
  25  *  distribution); if not, write to the Free Software Foundation, Inc.,
  26  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  27  */
  28
  29 typedef struct
  30 {
  31   volatile long count;
  32 } MUTEX;
  33
  34 #define MUTEX_SLEEP_TIME  10000 // microseconds
  35
  36 #define INIT_MUTEX(m) { (m)->count = 0; }
  37
  38 #define ACQUIRE_MUTEX_BLOCKING(m)                         \
  39 {                                                         \
  40     while (NdisInterlockedIncrement (&((m)->count)) != 1) \
  41     {                                                     \
  42         NdisInterlockedDecrement(&((m)->count));          \
  43         NdisMSleep(MUTEX_SLEEP_TIME);                     \
  44     }                                                     \
  45 }
  46
  47 #define RELEASE_MUTEX(m)                                  \
  48 {                                                         \
  49         NdisInterlockedDecrement(&((m)->count));          \
  50 }
  51
  52 #define ACQUIRE_MUTEX_NONBLOCKING(m, result)              \
  53 {                                                         \
  54     if (NdisInterlockedIncrement (&((m)->count)) != 1)    \
  55     {                                                     \
  56         NdisInterlockedDecrement(&((m)->count));          \
  57         result = FALSE;                                   \
  58     }                                                     \
  59     else                                                  \
  60     {                                                     \
  61         result = TRUE;                                    \
  62     }                                                     \
  63 }
  64
  65 #define ACQUIRE_MUTEX_ADAPTIVE(m, result)                 \
  66 {                                                         \
  67     result = TRUE;                                        \
  68     while (NdisInterlockedIncrement (&((m)->count)) != 1) \
  69     {                                                     \
  70         NdisInterlockedDecrement(&((m)->count));          \
  71         if (KeGetCurrentIrql () < DISPATCH_LEVEL)         \
  72             NdisMSleep(MUTEX_SLEEP_TIME);                 \
  73         else                                              \
  74         {                                                 \
  75             result = FALSE;                               \
  76             break;                                        \
  77         }                                                 \
  78     }                                                     \
  79 }