class apext::com::secoc::FVM

The member function apext::com::secoc::FVM::GetRxFreshness serves the SecOC layer to determine the full freshness value for received messages [SWS_CM_11288]. As input parameters, the function expects the identifier SecOCFreshnessValueID, the truncated freshness value extracted from the secured message in FVContainer according to [SWS_CM_11286], as well as the counter SecOCAuthVerifyAttempts [SWS_CM_11288]. This counter starts with value 0 on the first verification attempt and is incremented on each subsequent failed attempt for the same message [SWS_CM_11288].

The method is specified as noexcept and exception safe (AUTOSAR_AP_SWS_CommunicationManagement §C.1.2.2.1.1 “GetRxFreshness”). Due to the direct return of a ara::core::Result<FVContainer> without a future type, the call is expected to be processed synchronously blocking. Question Q-2609cb9ffeb0d41d (open) In case of success, the result contains the full freshness value for the subsequent MAC verification of the authenticator [SWS_CM_11288]. If the value cannot be provided, the function returns the recoverable error code ComSecOcFvmErrc::kFVNotAvailable [SWS_CM_11288].

Freshness value determination is an integral part of the SecOC reception path: Message authentication generally takes place prior to downstream E2E checks [SWS_CM_11276] and is coupled with the counter for authentication attempts [SWS_CM_11277]. Specific requirements for reentrancy or thread safety are not defined in the standard; behavior upon concurrent calls is therefore likely to depend on the concrete implementation of the Freshness Value Manager. Question Q-071e92f80c6e44db (open)

The synchronous library function apext::com::secoc::FVM::GetTxFreshness ([SWS_CM_11289]) serves SecOC processing to obtain the current freshness value when sending secured messages via Communication Management ([SWS_CM_11274], AUTOSAR_AP_SWS_CommunicationManagement p. 224 “SecOC secure channel sending”).

Usage and Call Context

The call is made by ara::com, provided that a freshnessValueId is stored in the configuration for the respective service interface element ([SWS_CM_11274]):

• Parameter: SecOCFreshnessValueID (type std::uint16_t) identifies the freshness value to be requested ([SWS_CM_11289]).
• Return value: A ara::core::Result<FVContainer> ([SWS_CM_11289]). In case of success, this contains a apext::com::secoc::FVContainer ([SWS_CM_11286]) whose freshness value is used for the subsequent authenticator or MAC calculation ([SWS_CM_11274]).
• Exception safety: The function is declared as noexcept ([SWS_CM_11289]).

Error Handling and Boundary Conditions

If no valid freshness value can be provided, the function returns a ara::core::Result with the error code ComSecOcFvmErrc::kFVNotAvailable ("Freshness Value not available") with rollback semantics ([SWS_CM_11289]). Specific notifications to DET or DEM are not defined for this interface in the Adaptive standard.

Sequence and concurrency

Within the sending process, the call is subject to a strict sequence ([SWS_CM_11274]):

1. Previously, the lifecycle of the Freshness Value Manager must have been managed by ara::com ([SWS_CM_11272]) and the instance initialized via apext::com::secoc::FVM::Initialize ([SWS_CM_11273]).
2. When sending, GetTxFreshness takes place downstream of the E2E protection calculations ([SWS_CM_11274]).
3. Subsequently, MAC calculation, optional truncations, and the assembly of the secured message are performed ([SWS_CM_11274]).

The specification is silent regarding reentrancy; however, the FVM implementation presumably needs to be designed thread-safe or reentrant if concurrent communication flows request freshness values simultaneously. Question Q-a1d3e04b91b6c24d (open)

Usage and Call Context

The synchronous library function Initialize within the scope apext::com::secoc::FVM serves to initialize the vendor-specific plugin implementation of the Freshness Value Manager (FVM) for safety- and security-relevant communication via SecOC [SWS_CM_11290]. The declaration is available via the header apext/com/secoc/fvm.h SWS CommunicationManagement §C.1.2.2.1.3 “Initialize”.

The function takes no parameters and declares the exception safety noexcept (exception safe) [SWS_CM_11290]. Lifecycle management of the FVM is mandatorily handled by the communication middleware ara::com [SWS_CM_11272], which performs the initialization of the FVM plugin by explicitly calling this interface [SWS_CM_11273]. Interpretation: No direct call context exists for application developers, as it is provided as a plugin for the platform and control resides entirely with ara::com. Question Q-5b5c8b1a42c3bd3a (open)

Error handling

The result of the operation is communicated via the return type ara::core::Result<void> [SWS_CM_11290]:

• Success: Upon successful initialization, the ara::core::Result contains an empty value (value_type is void) [SWS_CM_11290].
• Failed initialization: If the Freshness Value Manager could not be initialized, an error object with the specific error code ComSecOcFvmErrc::kFVInitializeFailed is returned; rollback semantics take effect here to maintain a defined state [SWS_CM_11290].

Interaction and Sequence

Initialization using Initialize forms the functional prerequisite for all further FVM services in the system [SWS_CM_11273]. Only after successful execution may ara::com access the interface apext::com::secoc::FVM::GetTxFreshness as part of SecOC send operations after the E2E calculation in order to retrieve freshness values for configured freshnessValueId attributes [SWS_CM_11274].

use

The synchronous method apext::com::secoc::FVM::SetVerificationStatus is called by SecOC to report the result of a verification to the Freshness Value Manager (FVM) [SWS_CM_19999]. It is declared via header apext/com/secoc/fvm.h and requires two parameters AUTOSAR_AP_SWS_CommunicationManagement §C.1.2.2.1.4 “SetVerificationStatus”:

• secOCFreshnessValueID (std::uint16_t): Unique identifier of the freshness value.
• secOCVerificationStatus (VerificationStatus): Verification result for the specified identifier.

Error Handling and Concurrency

The function is declared as noexcept and is considered exception safe (exception safe) [SWS_CM_19999]. The return type ara::core::Result<void> signals successful execution via an empty result. In case of error, the result object contains an error code of type ara::com::ComErrc, although the specification defines no specific standardized error codes [SWS_CM_19999].

Interplay and status

The function couples SecOC and the FVM in managing freshness values. It has the status DRAFT AUTOSAR_AP_SWS_CommunicationManagement §C.1.2.2.1.4 “SetVerificationStatus”. Interpretation: The transmitted status information is likely used internally by the FVM to update synchronization states or counter values of freshness values. Question Q-156ad8f991c99b7d (open)