515 lines
14 KiB
C
515 lines
14 KiB
C
/*++
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Copyright (c) 1997-2001 Microsoft Corporation
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Module Name:
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timer.c
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Abstract:
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Contains timer management structures.
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Author:
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Sanjay Anand (SanjayAn) 26-May-1997
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ChunYe
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Environment:
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Kernel mode
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Revision History:
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--*/
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#include "precomp.h"
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#pragma hdrstop
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BOOLEAN
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IPSecInitTimer()
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/*++
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Routine Description:
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Initialize the timer structures.
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Arguments:
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None
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Return Value:
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None
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--*/
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{
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PIPSEC_TIMER_LIST pTimerList;
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LONG i;
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INIT_LOCK(&g_ipsec.TimerLock);
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//
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// Allocate timer structures
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//
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for (i = 0; i < IPSEC_CLASS_MAX; i++) {
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pTimerList = &(g_ipsec.TimerList[i]);
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#if DBG
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pTimerList->atl_sig = atl_signature;
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#endif
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pTimerList->pTimers = IPSecAllocateMemory(
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sizeof(IPSEC_TIMER) * IPSecTimerListSize[i],
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IPSEC_TAG_TIMER);
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if (pTimerList->pTimers == NULL_PIPSEC_TIMER) {
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while (--i >= 0) {
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pTimerList = &(g_ipsec.TimerList[i]);
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IPSecFreeMemory(pTimerList->pTimers);
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}
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return FALSE;
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}
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}
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//
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// Initialize timer wheels.
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//
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for (i = 0; i < IPSEC_CLASS_MAX; i++) {
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pTimerList = &(g_ipsec.TimerList[i]);
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IPSecZeroMemory(pTimerList->pTimers,
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sizeof(IPSEC_TIMER) * IPSecTimerListSize[i]);
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pTimerList->MaxTimer = IPSecMaxTimerValue[i];
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pTimerList->TimerPeriod = IPSecTimerPeriod[i];
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pTimerList->TimerListSize = IPSecTimerListSize[i];
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IPSEC_INIT_SYSTEM_TIMER(
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&(pTimerList->NdisTimer),
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IPSecTickHandler,
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(PVOID)pTimerList);
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}
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return TRUE;
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}
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VOID
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IPSecStartTimer(
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IN PIPSEC_TIMER pTimer,
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IN IPSEC_TIMEOUT_HANDLER TimeoutHandler,
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IN ULONG SecondsToGo,
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IN PVOID Context
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)
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/*++
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Routine Description:
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Start an IPSEC timer. Based on the length (SecondsToGo) of the
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timer, we decide on whether to insert it in the short duration
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timer list or in the long duration timer list in the Interface
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structure.
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NOTE: the caller is assumed to either hold a lock to the structure
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that contains the timer, or ensure that it is safe to access the
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timer structure.
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Arguments:
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pTimer - Pointer to IPSEC Timer structure
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TimeoutHandler - Handler function to be called if this timer expires
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SecondsToGo - When does this timer go off?
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Context - To be passed to timeout handler if this timer expires
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Return Value:
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None
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--*/
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{
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PIPSEC_TIMER_LIST pTimerList; // List to which this timer goes
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PIPSEC_TIMER pTimerListHead; // Head of above list
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ULONG Index; // Into timer wheel
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ULONG TicksToGo = 1;
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KIRQL kIrql;
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INT i;
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IPSEC_DEBUG(TIMER,
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("StartTimer: Secs %d, Handler 0x%x, Ctxt 0x%x, pTimer 0x%x\n",
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SecondsToGo, TimeoutHandler, Context, pTimer));
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if (IPSEC_IS_TIMER_ACTIVE(pTimer)) {
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IPSEC_DEBUG(TIMER,
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("Start timer: pTimer 0x%x: is active (list 0x%x, hnd 0x%x), stopping it\n",
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pTimer, pTimer->pTimerList, pTimer->TimeoutHandler));
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if (!IPSecStopTimer(pTimer)) {
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IPSEC_DEBUG(TIMER, ("Couldnt stop prev timer - bail\n"));
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return;
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}
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}
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ACQUIRE_LOCK(&g_ipsec.TimerLock, &kIrql);
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ASSERT(!IPSEC_IS_TIMER_ACTIVE(pTimer));
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//
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// Find the list to which this timer should go, and the
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// offset (TicksToGo)
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//
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for (i = 0; i < IPSEC_CLASS_MAX; i++) {
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pTimerList = &(g_ipsec.TimerList[i]);
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if (SecondsToGo < pTimerList->MaxTimer) {
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//
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// Found it.
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//
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TicksToGo = SecondsToGo / (pTimerList->TimerPeriod);
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break;
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}
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}
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//
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// Find the position in the list for this timer
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//
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Index = pTimerList->CurrentTick + TicksToGo;
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if (Index >= pTimerList->TimerListSize) {
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Index -= pTimerList->TimerListSize;
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}
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ASSERT(Index < pTimerList->TimerListSize);
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pTimerListHead = &(pTimerList->pTimers[Index]);
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//
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// Fill in the timer
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//
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pTimer->pTimerList = pTimerList;
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pTimer->LastRefreshTime = pTimerList->CurrentTick;
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pTimer->Duration = TicksToGo;
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pTimer->TimeoutHandler = TimeoutHandler;
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pTimer->Context = Context;
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//
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// Insert this timer in the "ticking" list
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//
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pTimer->pPrevTimer = pTimerListHead;
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pTimer->pNextTimer = pTimerListHead->pNextTimer;
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if (pTimer->pNextTimer != NULL_PIPSEC_TIMER) {
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pTimer->pNextTimer->pPrevTimer = pTimer;
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}
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pTimerListHead->pNextTimer = pTimer;
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//
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// Start off the system tick timer if necessary.
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//
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pTimerList->TimerCount++;
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if (pTimerList->TimerCount == 1) {
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IPSEC_DEBUG(TIMER,
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("StartTimer: Starting system timer 0x%x, class %d\n",
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&(pTimerList->NdisTimer), i));
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IPSEC_START_SYSTEM_TIMER(&(pTimerList->NdisTimer), pTimerList->TimerPeriod);
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}
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RELEASE_LOCK(&g_ipsec.TimerLock, kIrql);
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//
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// We're done
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//
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IPSEC_DEBUG(TIMER,
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("Started timer 0x%x, Secs %d, Index %d, Head 0x%x\n",
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pTimer,
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SecondsToGo,
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Index,
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pTimerListHead));
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IPSEC_INCREMENT(g_ipsec.NumTimers);
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return;
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}
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BOOLEAN
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IPSecStopTimer(
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IN PIPSEC_TIMER pTimer
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)
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/*++
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Routine Description:
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Stop an IPSEC timer, if it is running. We remove this timer from
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the active timer list and mark it so that we know it's not running.
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NOTE: the caller is assumed to either hold a lock to the structure
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that contains the timer, or ensure that it is safe to access the
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timer structure.
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SIDE EFFECT: If we happen to stop the last timer (of this "duration") on
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the Interface, we also stop the appropriate Tick function.
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Arguments:
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pTimer - Pointer to IPSEC Timer structure
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Return Value:
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TRUE if the timer was running, FALSE otherwise.
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--*/
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{
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PIPSEC_TIMER_LIST pTimerList; // Timer List to which this timer belongs
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BOOLEAN WasRunning;
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KIRQL kIrql;
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IPSEC_DEBUG(TIMER,
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("Stopping Timer 0x%x, List 0x%x, Prev 0x%x, Next 0x%x\n",
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pTimer,
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pTimer->pTimerList,
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pTimer->pPrevTimer,
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pTimer->pNextTimer));
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ACQUIRE_LOCK(&g_ipsec.TimerLock, &kIrql);
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if (IPSEC_IS_TIMER_ACTIVE(pTimer)) {
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WasRunning = TRUE;
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//
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// Unlink timer from the list
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//
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ASSERT(pTimer->pPrevTimer); // the list head always exists
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if (pTimer->pPrevTimer) {
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pTimer->pPrevTimer->pNextTimer = pTimer->pNextTimer;
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}
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if (pTimer->pNextTimer) {
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pTimer->pNextTimer->pPrevTimer = pTimer->pPrevTimer;
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}
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pTimer->pNextTimer = pTimer->pPrevTimer = NULL_PIPSEC_TIMER;
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//
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// Update timer count on Interface, for this class of timers
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//
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pTimerList = pTimer->pTimerList;
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pTimerList->TimerCount--;
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//
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// If all timers of this class are gone, stop the system tick timer
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// for this class
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//
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if (pTimerList->TimerCount == 0) {
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IPSEC_DEBUG(TIMER, ("Stopping system timer 0x%x, List 0x%x\n",
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&(pTimerList->NdisTimer),
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pTimerList));
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pTimerList->CurrentTick = 0;
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IPSEC_STOP_SYSTEM_TIMER(&(pTimerList->NdisTimer));
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}
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//
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// Mark stopped timer as not active
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//
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pTimer->pTimerList = (PIPSEC_TIMER_LIST)NULL;
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IPSEC_DECREMENT(g_ipsec.NumTimers);
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} else {
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WasRunning = FALSE;
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}
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RELEASE_LOCK(&g_ipsec.TimerLock, kIrql);
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return WasRunning;
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}
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VOID
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IPSecTickHandler(
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IN PVOID SystemSpecific1,
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IN PVOID Context,
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IN PVOID SystemSpecific2,
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IN PVOID SystemSpecific3
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)
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/*++
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Routine Description:
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This is the handler we register with the system for processing each
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Timer List. This is called every "tick" seconds, where "tick" is
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determined by the granularity of the timer type.
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Arguments:
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Context - Actually a pointer to a Timer List structure
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SystemSpecific[1-3] - Not used
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Return Value:
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None
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--*/
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{
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PIPSEC_TIMER_LIST pTimerList;
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PIPSEC_TIMER pExpiredTimer; // Start of list of expired timers
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PIPSEC_TIMER pNextTimer; // for walking above list
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PIPSEC_TIMER pTimer; // temp, for walking timer list
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PIPSEC_TIMER pPrevExpiredTimer; // for creating expired timer list
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ULONG Index; // into the timer wheel
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ULONG NewIndex; // for refreshed timers
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KIRQL kIrql;
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pTimerList = (PIPSEC_TIMER_LIST)Context;
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IPSEC_DEBUG(TIMER, ("Tick: List 0x%x, Count %d\n",
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pTimerList, pTimerList->TimerCount));
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pExpiredTimer = NULL_PIPSEC_TIMER;
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ACQUIRE_LOCK(&g_ipsec.TimerLock, &kIrql);
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if (TRUE) {
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//
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// Pick up the list of timers scheduled to have expired at the
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// current tick. Some of these might have been refreshed.
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//
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Index = pTimerList->CurrentTick;
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pExpiredTimer = (pTimerList->pTimers[Index]).pNextTimer;
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(pTimerList->pTimers[Index]).pNextTimer = NULL_PIPSEC_TIMER;
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//
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// Go through the list of timers scheduled to expire at this tick.
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// Prepare a list of expired timers, using the pNextExpiredTimer
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// link to chain them together.
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//
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// Some timers may have been refreshed, in which case we reinsert
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// them in the active timer list.
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//
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pPrevExpiredTimer = NULL_PIPSEC_TIMER;
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for (pTimer = pExpiredTimer;
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pTimer != NULL_PIPSEC_TIMER;
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pTimer = pNextTimer) {
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//
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// Save a pointer to the next timer, for the next iteration.
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//
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pNextTimer = pTimer->pNextTimer;
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IPSEC_DEBUG(TIMER,
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("Tick Handler: looking at timer 0x%x, next 0x%x\n",
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pTimer, pNextTimer));
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//
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// Find out when this timer should actually expire.
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//
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NewIndex = pTimer->LastRefreshTime + pTimer->Duration;
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if (NewIndex >= pTimerList->TimerListSize) {
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NewIndex -= pTimerList->TimerListSize;
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}
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//
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// Check if we are currently at the point of expiry.
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//
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if (NewIndex != Index) {
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//
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// This timer still has some way to go, so put it back.
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//
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IPSEC_DEBUG(TIMER,
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("Tick: Reinserting Timer 0x%x: Hnd 0x%x, Durn %d, Ind %d, NewInd %d\n",
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pTimer, pTimer->TimeoutHandler, pTimer->Duration, Index, NewIndex));
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//
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// Remove it from the expired timer list. Note that we only
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// need to update the forward (pNextExpiredTimer) links.
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//
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if (pPrevExpiredTimer == NULL_PIPSEC_TIMER) {
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pExpiredTimer = pNextTimer;
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} else {
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pPrevExpiredTimer->pNextExpiredTimer = pNextTimer;
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}
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//
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// And insert it back into the running timer list.
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//
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pTimer->pNextTimer = (pTimerList->pTimers[NewIndex]).pNextTimer;
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if (pTimer->pNextTimer != NULL_PIPSEC_TIMER) {
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pTimer->pNextTimer->pPrevTimer = pTimer;
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}
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pTimer->pPrevTimer = &(pTimerList->pTimers[NewIndex]);
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(pTimerList->pTimers[NewIndex]).pNextTimer = pTimer;
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} else {
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//
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// This one has expired. Keep it in the expired timer list.
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//
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pTimer->pNextExpiredTimer = pNextTimer;
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if (pPrevExpiredTimer == NULL_PIPSEC_TIMER) {
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pExpiredTimer = pTimer;
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}
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pPrevExpiredTimer = pTimer;
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//
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// Mark it as inactive.
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//
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ASSERT(pTimer->pTimerList == pTimerList);
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pTimer->pTimerList = (PIPSEC_TIMER_LIST)NULL;
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//
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// Update the active timer count.
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//
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pTimerList->TimerCount--;
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}
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}
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//
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// Update current tick index in readiness for the next tick.
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//
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if (++Index == pTimerList->TimerListSize) {
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pTimerList->CurrentTick = 0;
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} else {
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pTimerList->CurrentTick = Index;
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}
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if (pTimerList->TimerCount > 0) {
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//
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// Re-arm the tick handler
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//
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IPSEC_DEBUG(TIMER, ("Tick[%d]: Starting system timer 0x%x\n",
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pTimerList->CurrentTick, &(pTimerList->NdisTimer)));
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IPSEC_START_SYSTEM_TIMER(&(pTimerList->NdisTimer), pTimerList->TimerPeriod);
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} else {
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pTimerList->CurrentTick = 0;
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}
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}
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RELEASE_LOCK(&g_ipsec.TimerLock, kIrql);
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//
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// Now pExpiredTimer is a list of expired timers.
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// Walk through the list and call the timeout handlers
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// for each timer.
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//
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while (pExpiredTimer != NULL_PIPSEC_TIMER) {
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pNextTimer = pExpiredTimer->pNextExpiredTimer;
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IPSEC_DEBUG(TIMER,
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("Expired timer 0x%x: handler 0x%x, next 0x%x\n",
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pExpiredTimer, pExpiredTimer->TimeoutHandler, pNextTimer));
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(*(pExpiredTimer->TimeoutHandler))( pExpiredTimer,
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pExpiredTimer->Context);
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IPSEC_DECREMENT(g_ipsec.NumTimers);
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pExpiredTimer = pNextTimer;
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}
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}
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