namespace ara::fw

The namespace ara::fw provides types and interfaces for Firewall control and its standardized error handling in the AUTOSAR Adaptive Platform. The module defines an interface for Firewall states with FirewallStateSwitchInterface and generates typed error objects based on the error domain FwErrorDomain [AP_SWS_Fw_83003] via the thread-safe function MakeErrorCode. Occurring problems are mapped by the enumeration FwErrc, which indicates, among other things, unavailable services or invalid state-dependent configurations [AP_SWS_Fw_83001]. All core functions for error generation are thread-safe and declared as noexcept.

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Context

Namespace ara::fw bundles the programming interfaces and types for the Firewall functionality of the AUTOSAR Adaptive Platform in release R25-11. The primary role of the module is to provide mechanisms for filtering and securing intra-vehicle network communication. Core components of the namespace include the interface FirewallStateSwitchInterface as well as the components for standardized error handling, consisting of FwErrorDomain, FwException, and the associated error codes. The architecture integrates seamlessly into the platform error concept of ara::core. External interaction partners, such as state-managing platform services or applications, use the namespace to control security-relevant Firewall states or resolve execution errors that occur. Interpretation: Class FirewallStateSwitchInterface presumably serves as the primary interface for activating and switching rule sets depending on the superordinate system state. Question Q-d4ba0994e0147cf1 (open)

Context diagram: Interaction of application, FirewallStateSwitchInterface, and FwErrorDomain during error resolution. Sources: [AP_SWS_Fw_83001], [AP_SWS_Fw_83002], [AP_SWS_Fw_83003].

Usage Path

The typical usage path in namespace ara::fw comprises initiating state changes as well as generating, forwarding, and evaluating error states during the execution of Firewall functions. If an operation fails in the context of FirewallStateSwitchInterface or a state request cannot be fulfilled, the module accesses the specific error domain to provide the caller with a precise diagnostic result. To instantiate such an error, function MakeErrorCode is called [AP_SWS_Fw_83003]. This function creates a ara::core::ErrorCode by accepting an error value from FwErrc [AP_SWS_Fw_83001] and optional vendor-specific supplementary data of type ara::core::ErrorDomain::SupportDataType [AP_SWS_Fw_83003]. Since MakeErrorCode is declared as constexpr and noexcept, error code creation can be performed in a resource-efficient and deterministic manner.

On the caller side, the returned error is usually received in a result object (such as ara::core::Result). The free function GetFwErrorDomain [AP_SWS_Fw_83002], which returns a constant reference to the singleton of the error domain FwErrorDomain, serves for programmatic verification of the error origin. Callers can use this to check whether an error that occurred actually originates from the Firewall module and to determine its textual description. Interpretation: In system architectures employing C++ exceptions, class FwException presumably serves the purpose of encapsulating the ara::core::ErrorCode so that it can be caught and forwarded synchronously to higher-level error handling routines. Question (open)

Error Scenarios

For error situations, enumeration FwErrc in namespace ara::fw defines specific error causes for error domain FwErrorDomain [AP_SWS_Fw_83001]. Header file ara/fw/fw_error_domain.h declares the following standardized error states:

• kServiceNotAvailable (value 1): Indicates that the addressed Firewall service is unreachable at runtime or is currently not operational [AP_SWS_Fw_83001]. Possible causes lie in not yet initialized background components or temporary connection drops. Preconditions for subsequent invocations are not met, so callers must query the service status or retry the request at a later time.
• kInvalidStateDependentFirewall (value 2): Occurs when a requested state-dependent Firewall configuration is invalid or an invalid state transition has been requested [AP_SWS_Fw_83001]. A precondition for successful switching operations is that the target Firewall supports the desired states and the system is in an admissible base state. After this error occurs, the Firewall remains unchanged in its previous protection mode.

Both error values are based on the base type ara::core::ErrorDomain::CodeType [AP_SWS_Fw_83001]. The functions GetFwErrorDomain [AP_SWS_Fw_83002] and MakeErrorCode [AP_SWS_Fw_83003] are explicitly declared as thread-safe (thread-safe) and noexcept, thereby ensuring safe error handling even in highly concurrent or time-critical contexts.