> ## Documentation Index
> Fetch the complete documentation index at: https://notevil.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# CAPLfunctionOnSecurityOfNodeQueryFreshness

[Open topic with navigation](../../../../../CANoeDEFamily.htm#Topics/CAPLFunctions/Security/CallbackHandler/CAPLfunctionOnSecurityOfNodeQueryFreshness.md)

## OnSecurityOfNodeQueryFreshness

[CAPL Functions](../../CAPLfunctions.md) » [Security](../CAPLFunctionsSecurityOverview.md) » OnSecurityOfNodeQueryFreshness

**Valid for:** CANoe DE • CANoe4SW DE

### Function Syntax

```
long OnSecurityOfNodeQueryFreshness(char nodeName[], char nameName[], dword context, char pduName[], dword dataId, dword freshnessValueId, dword attemptNr, byte payload[], dword payloadLength, qword& freshness, dword& freshnessLength, qword truncatedRxFreshness, dword truncatedRxFreshnessBitLength)
```

### Description

This callback is called for every secured PDU of the specified node on the specified network for which a MAC has to be calculated or verified. The callback is triggered before the MAC calculation starts. The callback provides the possibility to calculate a freshness value in CAPL and force the Security Manager to use this freshness value for the next MAC calculation/verification. You have to call [SecurityLocalStartControlSimulationNode](../Functions/CAPLfunctionSecurityLocalStartControlSimulationNode.md) before this callback is called.

### Parameters

* **char nodeName\[]**: The name of the node.
* **char networkName\[]**: The name of the network the node is on.
* **dword context**:
  * 1: PDU is received (MAC verification)
  * 0: PDU is transmitted (MAC calculation)
* **char pduName\[]**: The name of the PDU.
* **dword dataId**: The data ID of the PDU.
* **dword freshnessValueId**: The freshness value ID of the PDU.
* **dword attemptNr**: The number of the attempted verification.
* **byte payload\[]**: The payload of the PDU.
* **dword payloadLength**: The payload length of the PDU in bytes.
* **qword& freshness \[Out]**: The freshness the CAPL code provides.
* **dword& freshnessLength \[Out]**: The freshness length of the freshness the CAPL code provides in bits.
* **qword truncatedRxFreshness**: The received freshness (only in case context is 1).
* **dword truncatedRxFreshnessBitLength**: The received freshness length in bits (only in case context is 1).

### Return Values

* **qword& freshness \[Out]**: The freshness the CAPL code provides.

* **dword& freshnessLength \[Out]**: The freshness length of the freshness the CAPL code provides in bits.

* 0: No freshness is provided by this callback.

* 1: The freshness and freshnessLength shall be used for MAC calculation/verification.

### Example

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