[ICD] Subscription resumption should respect min interval on startup

src/app/InteractionModelEngine.cpp

@@ -1591,6 +1591,47 @@ CHIP_ERROR InteractionModelEngine::ResumeSubscriptions()
 #if CHIP_CONFIG_PERSIST_SUBSCRIPTIONS
     ReturnErrorCodeIf(!mpSubscriptionResumptionStorage, CHIP_NO_ERROR);
 
+    // To avoid the case of a reboot loop causing rapid traffic generation / power consumption, subscription resumption should make
+    // use of the persisted min-interval values, and wait before resumption. Ideally, each persisted subscription should wait their
+    // own min-interval value before resumption, but that both A) potentially runs into a timer resource issue, and B) having a
+    // low-powered device wake many times also has energy use implications. The logic below waits the largest of the persisted
+    // min-interval values before resuming subscriptions.
+
+    // Even though this causes subscription-to-subscription interaction by linking the min-interval values, this is the right thing
+    // to do for now because it's both simple and avoids the timer resource and multiple-wake problems. This issue is to track
+    // future improvements: https://github.com/project-chip/connectedhomeip/issues/25439
+
+    SubscriptionResumptionStorage::SubscriptionInfo subscriptionInfo;
+    auto * iterator           = mpSubscriptionResumptionStorage->IterateSubscriptions();
+    int subscriptionsToResume = 0;
+    uint16_t minInterval      = 0;
+    while (iterator->Next(subscriptionInfo))
+    {
+        subscriptionsToResume++;
+        minInterval = std::max(minInterval, subscriptionInfo.mMinInterval);
+    }
+    iterator->Release();
+
+    if (subscriptionsToResume)
+    {
+        ChipLogProgress(InteractionModel, "Resuming %d subscriptions in %u seconds", subscriptionsToResume, minInterval);
+        ReturnErrorOnFailure(mpExchangeMgr->GetSessionManager()->SystemLayer()->StartTimer(
+            System::Clock::Seconds16(minInterval),
+            [](System::Layer *, void * me) { static_cast<InteractionModelEngine *>(me)->ResumeSubscriptionsTimerCallback(); },
+            this));
+    }
+    else
+    {
+        ChipLogProgress(InteractionModel, "No subscriptions to resume");
+    }
+#endif // CHIP_CONFIG_PERSIST_SUBSCRIPTIONS
+
+    return CHIP_NO_ERROR;
+}
+
+CHIP_ERROR InteractionModelEngine::ResumeSubscriptionsTimerCallback()
+{
+#if CHIP_CONFIG_PERSIST_SUBSCRIPTIONS
     SubscriptionResumptionStorage::SubscriptionInfo subscriptionInfo;
     auto * iterator = mpSubscriptionResumptionStorage->IterateSubscriptions();
     while (iterator->Next(subscriptionInfo))

src/app/InteractionModelEngine.h

@@ -536,6 +536,8 @@ class InteractionModelEngine : public Messaging::UnsolicitedMessageHandler,
     void ShutdownMatchingSubscriptions(const Optional<FabricIndex> & aFabricIndex = NullOptional,
                                        const Optional<NodeId> & aPeerNodeId       = NullOptional);
 
+    CHIP_ERROR ResumeSubscriptionsTimerCallback();
+
     template <typename T, size_t N>
     void ReleasePool(ObjectList<T> *& aObjectList, ObjectPool<ObjectList<T>, N> & aObjectPool);
     template <typename T, size_t N>