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[timer] add NextFireTime class (openthread#10295)
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This commit introduces `NextFireTime`, a helper object for tracking
the next fire time along with the current time. It provides an
`UpdateIfEarlier(Time)` method to update the tracked next fire time
with a new given time only if it is earlier.

The `NextFireTime` class simplifies a common code pattern used across
modules to determine the earliest fire time when scheduling a timer.
It also ensures that the next fire time is never set before the
current time, improving code safety.
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@abtink
abtink authored May 28, 2024
1 parent ef10dec commit 10cff14
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Showing 15 changed files with 240 additions and 196 deletions.
95 changes: 35 additions & 60 deletions src/core/border_router/routing_manager.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1475,54 +1475,42 @@ void RoutingManager::RxRaTracker::RemoveOrDeprecateEntriesFromInactiveRouters(vo

void RoutingManager::RxRaTracker::ScheduleStaleTimer(void)
{
TimeMilli now = TimerMilli::GetNow();
TimeMilli onLinkStaleTime = now;
TimeMilli staleTime = now.GetDistantFuture();
bool foundOnLink = false;
NextFireTime staleTime;
TimeMilli onLinkStaleTime = staleTime.GetNow();
bool foundOnLink = false;

// For on-link prefixes, we consider stale time as when all on-link
// prefixes become stale (the latest stale time) but for route
// prefixes we consider the earliest stale time.

mStaleTimer.Stop();

for (const Router &router : mRouters)
{
for (const OnLinkPrefix &entry : router.mOnLinkPrefixes)
{
if (!entry.IsDeprecated())
{
TimeMilli entryStaleTime = Max(now, entry.GetStaleTime());

onLinkStaleTime = Max(onLinkStaleTime, entryStaleTime);
onLinkStaleTime = Max(onLinkStaleTime, Max(staleTime.GetNow(), entry.GetStaleTime()));
foundOnLink = true;
}
}

for (const RoutePrefix &entry : router.mRoutePrefixes)
{
TimeMilli entryStaleTime = Max(now, entry.GetStaleTime());

staleTime = Min(staleTime, entryStaleTime);
staleTime.UpdateIfEarlier(entry.GetStaleTime());
}
}

if (foundOnLink)
{
staleTime = Min(staleTime, onLinkStaleTime);
staleTime.UpdateIfEarlier(onLinkStaleTime);
}

if (mLocalRaHeader.IsValid())
{
TimeMilli raHeaderStaleTime = Max(now, mLocalRaHeaderUpdateTime + Time::SecToMsec(kRtrAdvStaleTime));

staleTime = Min(staleTime, raHeaderStaleTime);
staleTime.UpdateIfEarlier(mLocalRaHeaderUpdateTime + Time::SecToMsec(kRtrAdvStaleTime));
}

if (staleTime != now.GetDistantFuture())
{
mStaleTimer.FireAt(staleTime);
}
mStaleTimer.FireAt(staleTime);
}

void RoutingManager::RxRaTracker::HandleStaleTimer(void)
Expand All @@ -1545,13 +1533,13 @@ void RoutingManager::RxRaTracker::HandleExpirationTimer(void) { RemoveExpiredEnt

void RoutingManager::RxRaTracker::RemoveExpiredEntries(void)
{
TimeMilli now = TimerMilli::GetNow();
TimeMilli nextExpireTime = now.GetDistantFuture();
LifetimedPrefix::ExpirationChecker expirationChecker(now);
bool didRemove = false;
NextFireTime nextExpireTime;
bool didRemove = false;

for (Router &router : mRouters)
{
LifetimedPrefix::ExpirationChecker expirationChecker(nextExpireTime.GetNow());

didRemove |= router.mOnLinkPrefixes.RemoveAndFreeAllMatching(expirationChecker);
didRemove |= router.mRoutePrefixes.RemoveAndFreeAllMatching(expirationChecker);
}
Expand All @@ -1569,19 +1557,16 @@ void RoutingManager::RxRaTracker::RemoveExpiredEntries(void)
{
for (const OnLinkPrefix &entry : router.mOnLinkPrefixes)
{
nextExpireTime = Min(nextExpireTime, entry.GetExpireTime());
nextExpireTime.UpdateIfEarlier(entry.GetExpireTime());
}

for (const RoutePrefix &entry : router.mRoutePrefixes)
{
nextExpireTime = Min(nextExpireTime, entry.GetExpireTime());
nextExpireTime.UpdateIfEarlier(entry.GetExpireTime());
}
}

if (nextExpireTime != now.GetDistantFuture())
{
mExpirationTimer.FireAt(nextExpireTime);
}
mExpirationTimer.FireAt(nextExpireTime);
}

void RoutingManager::RxRaTracker::SignalTableChanged(void) { mSignalTask.Post(); }
Expand Down Expand Up @@ -1620,8 +1605,7 @@ void RoutingManager::RxRaTracker::UpdateRouterOnRx(Router &aRouter)

void RoutingManager::RxRaTracker::HandleRouterTimer(void)
{
TimeMilli now = TimerMilli::GetNow();
TimeMilli nextTime = now.GetDistantFuture();
NextFireTime nextTime;

for (Router &router : mRouters)
{
Expand All @@ -1639,7 +1623,7 @@ void RoutingManager::RxRaTracker::HandleRouterTimer(void)
continue;
}

if (router.mTimeout <= now)
if (router.mTimeout <= nextTime.GetNow())
{
router.mNsProbeCount++;

Expand All @@ -1650,21 +1634,19 @@ void RoutingManager::RxRaTracker::HandleRouterTimer(void)
continue;
}

router.mTimeout = now + ((router.mNsProbeCount < Router::kMaxNsProbes) ? Router::kNsProbeRetryInterval
router.mTimeout =
nextTime.GetNow() + ((router.mNsProbeCount < Router::kMaxNsProbes) ? Router::kNsProbeRetryInterval
: Router::kNsProbeTimeout);

SendNeighborSolicitToRouter(router);
}

nextTime = Min(nextTime, router.mTimeout);
nextTime.UpdateIfEarlier(router.mTimeout);
}

RemoveOrDeprecateEntriesFromInactiveRouters();

if (nextTime != now.GetDistantFuture())
{
mRouterTimer.FireAtIfEarlier(nextTime);
}
mRouterTimer.FireAt(nextTime);
}

void RoutingManager::RxRaTracker::SendNeighborSolicitToRouter(const Router &aRouter)
Expand Down Expand Up @@ -2635,8 +2617,8 @@ void RoutingManager::OnLinkPrefixManager::SavePrefix(const Ip6::Prefix &aPrefix,

void RoutingManager::OnLinkPrefixManager::HandleTimer(void)
{
TimeMilli now = TimerMilli::GetNow();
TimeMilli nextExpireTime = now.GetDistantFuture();
NextFireTime nextExpireTime;

Array<Ip6::Prefix, kMaxOldPrefixes> expiredPrefixes;

switch (GetState())
Expand All @@ -2646,27 +2628,27 @@ void RoutingManager::OnLinkPrefixManager::HandleTimer(void)
case kPublishing:
case kAdvertising:
case kDeprecating:
if (now >= mExpireTime)
if (nextExpireTime.GetNow() >= mExpireTime)
{
IgnoreError(Get<Settings>().RemoveBrOnLinkPrefix(mLocalPrefix));
SetState(kIdle);
}
else
{
nextExpireTime = mExpireTime;
nextExpireTime.UpdateIfEarlier(mExpireTime);
}
break;
}

for (OldPrefix &entry : mOldLocalPrefixes)
{
if (now >= entry.mExpireTime)
if (nextExpireTime.GetNow() >= entry.mExpireTime)
{
SuccessOrAssert(expiredPrefixes.PushBack(entry.mPrefix));
}
else
{
nextExpireTime = Min(nextExpireTime, entry.mExpireTime);
nextExpireTime.UpdateIfEarlier(entry.mExpireTime);
}
}

Expand All @@ -2677,10 +2659,7 @@ void RoutingManager::OnLinkPrefixManager::HandleTimer(void)
mOldLocalPrefixes.RemoveMatching(prefix);
}

if (nextExpireTime != now.GetDistantFuture())
{
mTimer.FireAtIfEarlier(nextExpireTime);
}
mTimer.FireAtIfEarlier(nextExpireTime);

Get<RoutingManager>().mRoutePublisher.Evaluate();
}
Expand Down Expand Up @@ -2782,9 +2761,8 @@ Error RoutingManager::RioAdvertiser::InvalidatPrevRios(RouterAdvert::TxMessage &

Error RoutingManager::RioAdvertiser::AppendRios(RouterAdvert::TxMessage &aRaMessage)
{
Error error = kErrorNone;
TimeMilli now = TimerMilli::GetNow();
TimeMilli nextTime = now.GetDistantFuture();
Error error = kErrorNone;
NextFireTime nextTime;
RioPrefixArray oldPrefixes;
NetworkData::Iterator iterator = NetworkData::kIteratorInit;
NetworkData::OnMeshPrefixConfig prefixConfig;
Expand Down Expand Up @@ -2867,7 +2845,7 @@ Error RoutingManager::RioAdvertiser::AppendRios(RouterAdvert::TxMessage &aRaMess

if (prefix.mIsDeprecating)
{
if (now >= prefix.mExpirationTime)
if (nextTime.GetNow() >= prefix.mExpirationTime)
{
SuccessOrExit(error = AppendRio(prefix.mPrefix, /* aRouteLifetime */ 0, aRaMessage));
continue;
Expand All @@ -2876,7 +2854,7 @@ Error RoutingManager::RioAdvertiser::AppendRios(RouterAdvert::TxMessage &aRaMess
else
{
prefix.mIsDeprecating = true;
prefix.mExpirationTime = now + kDeprecationTime;
prefix.mExpirationTime = nextTime.GetNow() + kDeprecationTime;
}

if (mPrefixes.PushBack(prefix) != kErrorNone)
Expand All @@ -2885,7 +2863,7 @@ Error RoutingManager::RioAdvertiser::AppendRios(RouterAdvert::TxMessage &aRaMess
SuccessOrExit(error = AppendRio(prefix.mPrefix, /* aRouteLifetime */ 0, aRaMessage));
}

nextTime = Min(nextTime, prefix.mExpirationTime);
nextTime.UpdateIfEarlier(prefix.mExpirationTime);
}

// Advertise all prefixes in `mPrefixes`
Expand All @@ -2896,16 +2874,13 @@ Error RoutingManager::RioAdvertiser::AppendRios(RouterAdvert::TxMessage &aRaMess

if (prefix.mIsDeprecating)
{
lifetime = TimeMilli::MsecToSec(prefix.mExpirationTime - now);
lifetime = TimeMilli::MsecToSec(prefix.mExpirationTime - nextTime.GetNow());
}

SuccessOrExit(error = AppendRio(prefix.mPrefix, lifetime, aRaMessage));
}

if (nextTime != now.GetDistantFuture())
{
mTimer.FireAtIfEarlier(nextTime);
}
mTimer.FireAtIfEarlier(nextTime);

exit:
return error;
Expand Down
26 changes: 9 additions & 17 deletions src/core/coap/coap.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -464,16 +464,15 @@ void CoapBase::HandleRetransmissionTimer(Timer &aTimer)

void CoapBase::HandleRetransmissionTimer(void)
{
TimeMilli now = TimerMilli::GetNow();
TimeMilli nextTime = now.GetDistantFuture();
NextFireTime nextTime;
Metadata metadata;
Ip6::MessageInfo messageInfo;

for (Message &message : mPendingRequests)
{
metadata.ReadFrom(message);

if (now >= metadata.mNextTimerShot)
if (nextTime.GetNow() >= metadata.mNextTimerShot)
{
#if OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE
if (message.IsRequest() && metadata.mObserve && metadata.mAcknowledged)
Expand All @@ -493,7 +492,7 @@ void CoapBase::HandleRetransmissionTimer(void)
// Increment retransmission counter and timer.
metadata.mRetransmissionsRemaining--;
metadata.mRetransmissionTimeout *= 2;
metadata.mNextTimerShot = now + metadata.mRetransmissionTimeout;
metadata.mNextTimerShot = nextTime.GetNow() + metadata.mRetransmissionTimeout;
metadata.UpdateIn(message);

// Retransmit
Expand All @@ -512,13 +511,10 @@ void CoapBase::HandleRetransmissionTimer(void)
}
}

nextTime = Min(nextTime, metadata.mNextTimerShot);
nextTime.UpdateIfEarlier(metadata.mNextTimerShot);
}

if (nextTime < now.GetDistantFuture())
{
mRetransmissionTimer.FireAt(nextTime);
}
mRetransmissionTimer.FireAt(nextTime);
}

void CoapBase::FinalizeCoapTransaction(Message &aRequest,
Expand Down Expand Up @@ -1590,28 +1586,24 @@ void ResponsesQueue::HandleTimer(Timer &aTimer)

void ResponsesQueue::HandleTimer(void)
{
TimeMilli now = TimerMilli::GetNow();
TimeMilli nextDequeueTime = now.GetDistantFuture();
NextFireTime nextDequeueTime;

for (Message &message : mQueue)
{
ResponseMetadata metadata;

metadata.ReadFrom(message);

if (now >= metadata.mDequeueTime)
if (nextDequeueTime.GetNow() >= metadata.mDequeueTime)
{
DequeueResponse(message);
continue;
}

nextDequeueTime = Min(nextDequeueTime, metadata.mDequeueTime);
nextDequeueTime.UpdateIfEarlier(metadata.mDequeueTime);
}

if (nextDequeueTime < now.GetDistantFuture())
{
mTimer.FireAt(nextDequeueTime);
}
mTimer.FireAt(nextDequeueTime);
}

void ResponsesQueue::ResponseMetadata::ReadFrom(const Message &aMessage)
Expand Down
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