FwpmEngineGetOption0 function (fwpmu.h)

Article
10/13/2021

The FwpmEngineGetOption0 function retrieves a filter engine option.

Syntax

DWORD FwpmEngineGetOption0(
  [in]  HANDLE             engineHandle,
  [in]  FWPM_ENGINE_OPTION option,
  [out] FWP_VALUE0         **value
);

Parameters

[in] engineHandle

Type: HANDLE

Handle for an open session to the filter engine. Call FwpmEngineOpen0 to open a session to the filter engine.

[in] option

Type: FWPM_ENGINE_OPTION

The option to be retrieved.

[out] value

Type: FWP_VALUE0**

The option value. The data type contained in the value parameter will be FWP_UINT32.

If option is FWPM_ENGINE_COLLECT_NET_EVENTS, value will be one of the following.

Value	Meaning
0	Network events are not being collected.
1	Network events are being collected.

If option is FWPM_ENGINE_NET_EVENT_MATCH_ANY_KEYWORDS, value will be a bitwise combination of the following values.

Value	Meaning
FWPM_NET_EVENT_KEYWORD_INBOUND_MCAST 1	Inbound multicast network events are being collected.
FWPM_NET_EVENT_KEYWORD_INBOUND_BCAST 2	Inbound broadcast network events are not being collected.

If option is FWPM_ENGINE_PACKET_QUEUING (available only in Windows 8 and Windows Server 2012), value will be one of the following.

Value	Meaning
FWPM_ENGINE_OPTION_PACKET_QUEUE_NONE 0	No packet queuing is enabled.
FWPM_ENGINE_OPTION_PACKET_QUEUE_INBOUND 1	Inbound packet queuing is enabled.
FWPM_ENGINE_OPTION_PACKET_QUEUE_OUTBOUND 2	Outbound packet queuing is enabled.

If option is FWPM_ENGINE_MONITOR_IPSEC_CONNECTIONS (available only in Windows 8 and Windows Server 2012), value will be one of the following.

Value	Meaning
0	The IPsec Connection Monitoring feature is disabled. No IPsec connection events or notifications are being logged.
1	The IPsec Connection Monitoring feature is enabled. New IPsec connection events and notifications are being logged.

If option is FWPM_ENGINE_TXN_WATCHDOG_TIMEOUT_IN_MSEC (available only in Windows 8 and Windows Server 2012), value will be the time in milliseconds that specifies the maximum duration for a single WFP transaction. Transactions taking longer than this duration will trigger a watchdog event.

The FWPM_ENGINE_NAME_CACHE option is reserved for internal use.

Return value

Type: DWORD

Return code/value	Description
ERROR_SUCCESS 0	The option was retrieved successfully.
*FWP_E_ error code** 0x80320001—0x80320039	A Windows Filtering Platform (WFP) specific error. See WFP Error Codes for details.
*RPC_ error code** 0x80010001—0x80010122	Failure to communicate with the remote or local firewall engine.

Remarks

The caller must free the returned object by a call to FwpmFreeMemory0.

The caller needs FWPM_ACTRL_READ access to the filter engine. See Access Control for more information.

FwpmEngineGetOption0 is a specific implementation of FwpmEngineGetOption. See WFP Version-Independent Names and Targeting Specific Versions of Windows for more information.

Examples

The following C++ example illustrates the use of FwpmEngineGetOption0 to determine if network events are being collected.

#include <windows.h>
#include <fwpmu.h>
#include <stdio.h>

#pragma comment(lib, "Fwpuclnt.lib")

void main()
{
    HANDLE engineHandle = NULL; 
    DWORD  result = ERROR_SUCCESS; 

    FWPM_ENGINE_OPTION option = FWPM_ENGINE_COLLECT_NET_EVENTS;
    FWP_VALUE0* fwpValue = NULL;

    result = FwpmEngineOpen0( NULL, RPC_C_AUTHN_WINNT, NULL, NULL, &engineHandle );
    if (result != ERROR_SUCCESS)
    {
        printf("FwpmEngineOpen0 failed.\n");
        return;
    }

    result = FwpmEngineGetOption0( engineHandle, option, &fwpValue);

    if (result != ERROR_SUCCESS)
    {
        printf("FwpmEngineGetOption0 failed.\n");
        return;
    }
    else if(fwpValue->type == FWP_UINT32)
    {
        if(fwpValue->uint32 == 1 ) 
            printf("Network events are being collected.\n");
        else
            printf("Network events are NOT being collected.\n");
    }
    else
        printf("Unexpected data type received.\n");

    FwpmFreeMemory0((void**)&fwpValue); 

    return;
}

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2008 [desktop apps only]
Target Platform	Windows
Header	fwpmu.h
Library	Fwpuclnt.lib
DLL	Fwpuclnt.dll

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