GetIpForwardTable2 function

The GetIpForwardTable2 function retrieves the IP route entries on a local computer.

Syntax


NETIOAPI_API GetIpForwardTable2(
  _In_   ADDRESS_FAMILY Family,
  _Out_  PMIB_IPFORWARD_TABLE2 *Table
);

Parameters

Family [in]

The address family to retrieve.

Possible values for the address family are listed in the Winsock2.h header file. Note that the values for the AF_ address family and PF_ protocol family constants are identical (for example, AF_INET and PF_INET), so you can use either constant.

On Windows Vista and later versions of the Windows operating systems, possible values for the Family parameter are defined in the Ws2def.h header file. Note that the Ws2def.h header file is automatically included in Netioapi.h and you should never use Ws2def.h directly.

The following values are currently supported for the address family:

AF_INET

The IPv4 address family. When this value is specified, this function returns the IP routing table that contains only IPv4 entries.

AF_INET6

The IPv6 address family. When this value is specified, this function returns the IP routing table that contains only IPv6 entries.

AF_UNSPEC

The address family is unspecified. When this value is specified, this function returns the IP routing table that contains both IPv4 and IPv6 entries.

Table [out]

A pointer to a MIB_IPFORWARD_TABLE2 structure that contains a table of IP route entries on the local computer.

Return value

GetIpForwardTable2 returns STATUS_SUCCESS if the function succeeds.

If the function fails, GetIpForwardTable2 returns one of the following error codes:

Return codeDescription
STATUS_INVALID_PARAMETER

An invalid parameter was passed to the function. This error is returned if a NULL pointer is passed in the Table parameter or the Family parameter was not specified as AF_INET, AF_INET6, or AF_UNSPEC.

STATUS_NOT_ENOUGH_MEMORY

Insufficient memory resources are available to complete the operation.

STATUS_NOT_FOUND

No IP route entries, as specified in the Family parameter, were found.

STATUS_NOT_SUPPORTED

The request is not supported. This error is returned if no IPv4 stack is located on the local computer and AF_INET was specified in the Family parameter, or if no IPv6 stack is located on the local computer and AF_INET6 was specified in the Family parameter. This error is also returned on versions of Windows where this function is not supported.

Other

Use the FormatMessage function to obtain the message string for the returned error.

 

Remarks

The GetIpForwardTable2 function enumerates the IP route entries on a local computer and returns this information in a MIB_IPFORWARD_TABLE2 structure.

The IP route entries are returned in a MIB_IPFORWARD_TABLE2 structure in the buffer that the Table parameter points to. The MIB_IPFORWARD_TABLE2 structure contains an IP route entry count and an array of MIB_IPFORWARD_ROW2 structures for each IP route entry. When these returned structures are no longer required, your driver should free the memory by calling FreeMibTable.

Your driver must initialize the Family parameter to either AF_INET, AF_INET6, or AF_UNSPEC.

Note that the returned MIB_IPFORWARD_TABLE2 structure that the Table parameter points to might contain padding for alignment between the NumEntries member and the first MIB_IPFORWARD_ROW2 array entry in the Table member of the MIB_IPFORWARD_TABLE2 structure. Padding for alignment might also be present between the MIB_IPFORWARD_ROW2 array entries. Any access to a MIB_IPFORWARD_ROW2 array entry should assume padding might exist.

Requirements

Version

Available in Windows Vista and later versions of the Windows operating systems.

Header

Netioapi.h (include Netioapi.h)

IRQL

< DISPATCH_LEVEL

See also

CreateIpForwardEntry2
DeleteIpForwardEntry2
FreeMibTable
GetBestRoute2
GetIpForwardEntry2
InitializeIpForwardEntry
MIB_IPFORWARD_ROW2
MIB_IPFORWARD_TABLE2
NotifyRouteChange2
SetIpForwardEntry2

 

 

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