Establish CASE on re-subscription

src/app/BufferedReadCallback.h

@@ -86,9 +86,9 @@ class BufferedReadCallback : public ReadClient::Callback
         mCallback.OnSubscriptionEstablished(aSubscriptionId);
     }
 
-    void OnResubscriptionAttempt(CHIP_ERROR aTerminationCause, uint32_t aNextResubscribeIntervalMsec) override
+    CHIP_ERROR OnResubscriptionNeeded(ReadClient * apReadClient, CHIP_ERROR aTerminationCause) override
     {
-        mCallback.OnResubscriptionAttempt(aTerminationCause, aNextResubscribeIntervalMsec);
+        return mCallback.OnResubscriptionNeeded(apReadClient, aTerminationCause);
     }
 
     void OnDeallocatePaths(chip::app::ReadPrepareParams && aReadPrepareParams) override

src/app/ClusterStateCache.h

@@ -576,9 +576,9 @@ class ClusterStateCache : protected ReadClient::Callback
         mCallback.OnSubscriptionEstablished(aSubscriptionId);
     }
 
-    void OnResubscriptionAttempt(CHIP_ERROR aTerminationCause, uint32_t aNextResubscribeIntervalMsec) override
+    CHIP_ERROR OnResubscriptionNeeded(ReadClient * apReadClient, CHIP_ERROR aTerminationCause) override
     {
-        mCallback.OnResubscriptionAttempt(aTerminationCause, aNextResubscribeIntervalMsec);
+        return mCallback.OnResubscriptionNeeded(apReadClient, aTerminationCause);
     }
 
     void OnDeallocatePaths(chip::app::ReadPrepareParams && aReadPrepareParams) override

src/app/DeviceProxy.h

@@ -27,7 +27,6 @@
 #pragma once
 
 #include <app/CommandSender.h>
-#include <app/InteractionModelEngine.h>
 #include <lib/core/CHIPCallback.h>
 #include <lib/core/CHIPCore.h>
 #include <lib/support/DLLUtil.h>

src/app/InteractionModelEngine.cpp

@@ -43,13 +43,17 @@ InteractionModelEngine * InteractionModelEngine::GetInstance()
     return &sInteractionModelEngine;
 }
 
-CHIP_ERROR InteractionModelEngine::Init(Messaging::ExchangeManager * apExchangeMgr, FabricTable * apFabricTable)
+CHIP_ERROR InteractionModelEngine::Init(Messaging::ExchangeManager * apExchangeMgr, FabricTable * apFabricTable,
+                                        CASESessionManager * apCASESessionMgr)
 {
-    mpExchangeMgr = apExchangeMgr;
-    mpFabricTable = apFabricTable;
+    VerifyOrReturnError(apFabricTable != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
+    VerifyOrReturnError(apExchangeMgr != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
+
+    mpExchangeMgr    = apExchangeMgr;
+    mpFabricTable    = apFabricTable;
+    mpCASESessionMgr = apCASESessionMgr;
 
     ReturnErrorOnFailure(mpExchangeMgr->RegisterUnsolicitedMessageHandlerForProtocol(Protocols::InteractionModel::Id, this));
-    VerifyOrReturnError(mpFabricTable != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
 
     mReportingEngine.Init();
     mMagic++;
@@ -122,6 +126,16 @@ void InteractionModelEngine::Shutdown()
     mEventPathPool.ReleaseAll();
     mDataVersionFilterPool.ReleaseAll();
     mpExchangeMgr->UnregisterUnsolicitedMessageHandlerForProtocol(Protocols::InteractionModel::Id);
+
+    mpCASESessionMgr = nullptr;
+
+    //
+    // We _should_ be clearing these out, but doing so invites a world
+    // of trouble. #21233 tracks fixing the underlying assumptions to make
+    // this possible.
+    //
+    // mpFabricTable    = nullptr;
+    // mpExchangeMgr    = nullptr;
 }
 
 uint32_t InteractionModelEngine::GetNumActiveReadHandlers() const

src/app/InteractionModelEngine.h

@@ -59,6 +59,8 @@
 #include <app/util/attribute-metadata.h>
 #include <app/util/basic-types.h>
 
+#include <app/CASESessionManager.h>
+
 namespace chip {
 namespace app {
 
@@ -102,17 +104,28 @@ class InteractionModelEngine : public Messaging::UnsolicitedMessageHandler,
      *  Initialize the InteractionModel Engine.
      *
      *  @param[in]    apExchangeMgr    A pointer to the ExchangeManager object.
+     *  @param[in]    apFabricTable    A pointer to the FabricTable object.
+     *  @param[in]    apCASESessionMgr An optional pointer to a CASESessionManager (used for re-subscriptions).
      *
      *  @retval #CHIP_ERROR_INCORRECT_STATE If the state is not equal to
      *          kState_NotInitialized.
      *  @retval #CHIP_NO_ERROR On success.
      *
      */
-    CHIP_ERROR Init(Messaging::ExchangeManager * apExchangeMgr, FabricTable * apFabricTable);
+    CHIP_ERROR Init(Messaging::ExchangeManager * apExchangeMgr, FabricTable * apFabricTable,
+                    CASESessionManager * apCASESessionMgr = nullptr);
 
     void Shutdown();
 
-    Messaging::ExchangeManager * GetExchangeManager(void) const { return mpExchangeMgr; };
+    Messaging::ExchangeManager * GetExchangeManager(void) const { return mpExchangeMgr; }
+
+    /**
+     * Returns a pointer to the CASESessionManager. This can return nullptr if one wasn't
+     * provided in the call to Init().
+     */
+    CASESessionManager * GetCASESessionManager() const { return mpCASESessionMgr; }
+
+    FabricTable * GetFabricTable() const { return mpFabricTable; }
 
     /**
      * Tears down an active subscription.
@@ -551,6 +564,8 @@ class InteractionModelEngine : public Messaging::UnsolicitedMessageHandler,
 
     FabricTable * mpFabricTable;
 
+    CASESessionManager * mpCASESessionMgr = nullptr;
+
     // A magic number for tracking values between stack Shutdown()-s and Init()-s.
     // An ObjectHandle is valid iff. its magic equals to this one.
     uint32_t mMagic = 0;

src/app/OperationalDeviceProxy.cpp

@@ -24,12 +24,11 @@
  *    messages to and from the corresponding CHIP devices.
  */
 
-#include "OperationalDeviceProxy.h"
+#include <app/OperationalDeviceProxy.h>
 
-#include "CASEClient.h"
-#include "CommandSender.h"
-#include "ReadPrepareParams.h"
-#include "transport/SecureSession.h"
+#include <app/CASEClient.h>
+#include <app/InteractionModelEngine.h>
+#include <transport/SecureSession.h>
 
 #include <lib/address_resolve/AddressResolve.h>
 #include <lib/core/CHIPCore.h>