ICD: Checking counter check moved from CheckInHandler to CheckinMessage.

[rcasallas-silabs]

Summary

ICD: Checking counter check moved from CheckInHandler to CheckinMessage.

Related issues

MATTER-2246.

Testing

UNTESTED.

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[gemini-code-assist]

Code Review

This pull request refactors the ICD check-in message processing by moving duplicate message detection logic from CheckInHandler into CheckinMessage::ParseCheckinMessagePayload. The ProcessCheckInPayload interface has been updated to handle counter offsets directly. A significant issue was identified in DefaultICDClientStorage::ProcessCheckInPayload where the lastErr variable is initialized but never updated within the loop, which prevents the function from returning specific error codes such as CHIP_ERROR_DUPLICATE_MESSAGE_RECEIVED when a duplicate message is correctly identified during decryption.

[gemini-code-assist]

The lastErr variable is initialized to CHIP_ERROR_NOT_FOUND but is never updated within the loop. This results in the function always returning CHIP_ERROR_NOT_FOUND if no successful match is found, masking more specific errors like CHIP_ERROR_DUPLICATE_MESSAGE_RECEIVED.

Since check-in message keys are unique per client, if ParseCheckinMessagePayload returns CHIP_ERROR_DUPLICATE_MESSAGE_RECEIVED, it confirms that the correct client was found (as decryption succeeded) but the message is a duplicate. The loop should terminate and return this specific error to allow the caller to log or handle the duplicate correctly.

    CHIP_ERROR lastErr = CHIP_ERROR_NOT_FOUND;

    while (iterator->Next(clientInfo))
    {
        CHIP_ERROR err = chip::Protocols::SecureChannel::CheckinMessage::ParseCheckinMessagePayload(
            clientInfo.aes_key_handle, clientInfo.hmac_key_handle, clientInfo.start_icd_counter, clientInfo.offset, payload, offset,
            appData);
        if (CHIP_NO_ERROR == err)
        {
            clientInfo.offset = offset;
            iterator->Release();
            return CHIP_NO_ERROR;
        }

        if (err == CHIP_ERROR_DUPLICATE_MESSAGE_RECEIVED)
        {
            lastErr = err;
            break;
        }
    }
    iterator->Release();
    return lastErr;