Changes to CommandSender and CommandHandler for supporting commands

with large payloads.

Author: pidarped

src/app/CommandHandlerExchangeInterface.h

@@ -102,6 +102,18 @@ class CommandHandlerExchangeInterface
      * Called by CommandHandler to relay this information to the requester.
      */
     virtual void ResponseDropped() = 0;
+
+    /**
+     * @brief Gets the maximum size of a packet buffer to encode a Command
+     * message. This size depends on the underlying session used by the
+     * exchange.
+     *
+     * The size returned here is the size not including the prepended headers.
+     *
+     * Called by CommandHandler when allocating buffer for encoding the Command
+     * response.
+     */
+    virtual size_t GetCommandMaxBufferSize() = 0;
 };
 
 } // namespace app

src/app/CommandHandlerImpl.cpp

@@ -58,14 +58,17 @@ CommandHandlerImpl::~CommandHandlerImpl()
 
 CHIP_ERROR CommandHandlerImpl::AllocateBuffer()
 {
+    System::PacketBufferHandle commandPacket = nullptr;
     // We should only allocate a buffer if we will be sending out a response.
     VerifyOrReturnError(ResponsesAccepted(), CHIP_ERROR_INCORRECT_STATE);
 
     if (!mBufferAllocated)
     {
         mCommandMessageWriter.Reset();
 
-        System::PacketBufferHandle commandPacket = System::PacketBufferHandle::New(chip::app::kMaxSecureSduLengthBytes);
+        size_t commandBufferMaxSize = mpResponder->GetCommandMaxBufferSize();
+        commandPacket               = System::PacketBufferHandle::New(commandBufferMaxSize);
+
         VerifyOrReturnError(!commandPacket.IsNull(), CHIP_ERROR_NO_MEMORY);
 
         mCommandMessageWriter.Init(std::move(commandPacket));

src/app/CommandResponseSender.cpp

@@ -206,6 +206,10 @@ void CommandResponseSender::OnInvokeCommandRequest(Messaging::ExchangeContext *
     VerifyOrDieWithMsg(ec != nullptr, DataManagement, "Incoming exchange context should not be null");
     VerifyOrDieWithMsg(mState == State::ReadyForInvokeResponses, DataManagement, "state should be ReadyForInvokeResponses");
 
+    if (ec->GetSessionHandle()->AllowsLargePayload())
+    {
+        mUseLargePayloadBuffer = true;
+    }
     // NOTE: we already know this is an InvokeRequestMessage because we explicitly registered with the
     // Exchange Manager for unsolicited InvokeRequestMessages.
     mExchangeCtx.Grab(ec);
@@ -226,6 +230,21 @@ void CommandResponseSender::OnInvokeCommandRequest(Messaging::ExchangeContext *
     }
 }
 
+size_t CommandResponseSender::GetCommandMaxBufferSize()
+{
+    VerifyOrExit(mExchangeCtx && mExchangeCtx->HasSessionHandle(),
+                 ChipLogError(DataManagement, "Session not available. Unable to infer session-specific buffer capacities."));
+
+    if (mExchangeCtx->GetSessionHandle()->AllowsLargePayload())
+    {
+        return kMaxLargeSecureSduLengthBytes;
+    }
+
+exit:
+
+    return kMaxSecureSduLengthBytes;
+}
+
 #if CHIP_WITH_NLFAULTINJECTION
 
 void CommandResponseSender::TestOnlyInvokeCommandRequestWithFaultsInjected(Messaging::ExchangeContext * ec,

src/app/CommandResponseSender.h

@@ -124,6 +124,8 @@ class CommandResponseSender : public Messaging::ExchangeDelegate,
 
     void ResponseDropped() override { mReportResponseDropped = true; }
 
+    size_t GetCommandMaxBufferSize() override;
+
     /*
      * Main entrypoint for this class to handle an invoke request.
      *
@@ -188,6 +190,7 @@ class CommandResponseSender : public Messaging::ExchangeDelegate,
     State mState = State::ReadyForInvokeResponses;
 
     bool mReportResponseDropped = false;
+    bool mUseLargePayloadBuffer = false;
 };
 
 } // namespace app

src/app/CommandSender.cpp

@@ -55,18 +55,19 @@ CHIP_ERROR GetRef(ParserT aParser, Optional<uint16_t> & aRef, bool commandRefReq
 } // namespace
 
 CommandSender::CommandSender(Callback * apCallback, Messaging::ExchangeManager * apExchangeMgr, bool aIsTimedRequest,
-                             bool aSuppressResponse) :
+                             bool aSuppressResponse, bool aRequireLargePayload) :
     mExchangeCtx(*this),
-    mCallbackHandle(apCallback), mpExchangeMgr(apExchangeMgr), mSuppressResponse(aSuppressResponse), mTimedRequest(aIsTimedRequest)
+    mCallbackHandle(apCallback), mpExchangeMgr(apExchangeMgr), mSuppressResponse(aSuppressResponse), mTimedRequest(aIsTimedRequest),
+    mRequireLargePayload(aRequireLargePayload)
 {
     assertChipStackLockedByCurrentThread();
 }
 
 CommandSender::CommandSender(ExtendableCallback * apExtendableCallback, Messaging::ExchangeManager * apExchangeMgr,
-                             bool aIsTimedRequest, bool aSuppressResponse) :
+                             bool aIsTimedRequest, bool aSuppressResponse, bool aRequireLargePayload) :
     mExchangeCtx(*this),
     mCallbackHandle(apExtendableCallback), mpExchangeMgr(apExchangeMgr), mSuppressResponse(aSuppressResponse),
-    mTimedRequest(aIsTimedRequest), mUseExtendableCallback(true)
+    mTimedRequest(aIsTimedRequest), mUseExtendableCallback(true), mRequireLargePayload(aRequireLargePayload)
 {
     assertChipStackLockedByCurrentThread();
 #if CHIP_CONFIG_COMMAND_SENDER_BUILTIN_SUPPORT_FOR_BATCHED_COMMANDS
@@ -85,7 +86,15 @@ CHIP_ERROR CommandSender::AllocateBuffer()
     {
         mCommandMessageWriter.Reset();
 
-        System::PacketBufferHandle commandPacket = System::PacketBufferHandle::New(chip::app::kMaxSecureSduLengthBytes);
+        System::PacketBufferHandle commandPacket;
+        if (mRequireLargePayload)
+        {
+            commandPacket = System::PacketBufferHandle::New(kMaxLargeSecureSduLengthBytes);
+        }
+        else
+        {
+            commandPacket = System::PacketBufferHandle::New(kMaxSecureSduLengthBytes);
+        }
         VerifyOrReturnError(!commandPacket.IsNull(), CHIP_ERROR_NO_MEMORY);
 
         mCommandMessageWriter.Init(std::move(commandPacket));
@@ -139,6 +148,12 @@ CHIP_ERROR CommandSender::TestOnlyCommandSenderTimedRequestFlagWithNoTimedInvoke
 
 CHIP_ERROR CommandSender::SendCommandRequest(const SessionHandle & session, Optional<System::Clock::Timeout> timeout)
 {
+    // If the command is expected to be large, ensure that the underlying
+    // session supports it.
+    if (mRequireLargePayload)
+    {
+        VerifyOrReturnError(session->AllowsLargePayload(), CHIP_ERROR_INCORRECT_STATE);
+    }
 
     if (mTimedRequest != mTimedInvokeTimeoutMs.HasValue())
     {

src/app/CommandSender.h

@@ -308,18 +308,19 @@ class CommandSender final : public Messaging::ExchangeDelegate
      * If callbacks are passed the only one that will be called in a group sesttings is the onDone
      */
     CommandSender(Callback * apCallback, Messaging::ExchangeManager * apExchangeMgr, bool aIsTimedRequest = false,
-                  bool aSuppressResponse = false);
+                  bool aSuppressResponse = false, bool aRequireLargePayload = false);
     CommandSender(std::nullptr_t, Messaging::ExchangeManager * apExchangeMgr, bool aIsTimedRequest = false,
-                  bool aSuppressResponse = false) :
-        CommandSender(static_cast<Callback *>(nullptr), apExchangeMgr, aIsTimedRequest, aSuppressResponse)
+                  bool aSuppressResponse = false, bool aRequireLargePayload = false) :
+        CommandSender(static_cast<Callback *>(nullptr), apExchangeMgr, aIsTimedRequest, aSuppressResponse, aRequireLargePayload)
     {}
     CommandSender(ExtendableCallback * apCallback, Messaging::ExchangeManager * apExchangeMgr, bool aIsTimedRequest = false,
-                  bool aSuppressResponse = false);
+                  bool aSuppressResponse = false, bool aRequireLargePayload = false);
     // TODO(#32138): After there is a macro that is always defined for all unit tests, the constructor with
     // TestOnlyMarker should only be compiled if that macro is defined.
     CommandSender(TestOnlyMarker aTestMarker, ExtendableCallback * apCallback, Messaging::ExchangeManager * apExchangeMgr,
-                  PendingResponseTracker * apPendingResponseTracker, bool aIsTimedRequest = false, bool aSuppressResponse = false) :
-        CommandSender(apCallback, apExchangeMgr, aIsTimedRequest, aSuppressResponse)
+                  PendingResponseTracker * apPendingResponseTracker, bool aIsTimedRequest = false, bool aSuppressResponse = false,
+                  bool aRequireLargePayload = false) :
+        CommandSender(apCallback, apExchangeMgr, aIsTimedRequest, aSuppressResponse, aRequireLargePayload)
     {
         mpPendingResponseTracker = apPendingResponseTracker;
     }
@@ -636,6 +637,7 @@ class CommandSender final : public Messaging::ExchangeDelegate
     bool mBufferAllocated       = false;
     bool mBatchCommandsEnabled  = false;
     bool mUseExtendableCallback = false;
+    bool mRequireLargePayload   = false;
 };
 
 } // namespace app

src/app/tests/TestCommandInteraction.cpp

@@ -330,6 +330,8 @@ class MockCommandResponder : public CommandHandlerExchangeInterface
     void AddInvokeResponseToSend(System::PacketBufferHandle && aPacket) override { mChunks.AddToEnd(std::move(aPacket)); }
     void ResponseDropped() override { mResponseDropped = true; }
 
+    size_t GetCommandMaxBufferSize() override { return kMaxSecureSduLengthBytes; }
+
     System::PacketBufferHandle mChunks;
     bool mResponseDropped = false;
 };