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GetIpForwardTable2 (NETIOAPI) (Compact 2013)

  • Article

3/26/2014

This function retrieves the IP route entries on a local device.

Syntax

NETIOAPI_API
  GetIpForwardTable2(
    IN ADDRESS_FAMILY  Family,
    OUT PMIB_IPFORWARD_TABLE2*  Table
    );

Parameters

  • Family
    The address family to retrieve.

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

    Possible values for the Family parameter are defined in the Ws2def.h header file. Be aware 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_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.
    • 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.
  • Table
    A pointer to a MIB_IPFORWARD_TABLE2 structure that contains a table of IP route entries on the local device.

Return Value

GetIpForwardTable2 returns STATUS_SUCCESS if the function succeeds.

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

Error Code

Meaning

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 device and AF_INET was specified in the Family parameter, or if no IPv6 stack is located on the local device 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 device 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 the FreeMibTable (NETIOAPI).

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

Be aware 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.

See Also

Reference

IP Helper Kernel-Mode Functions
CreateIpForwardEntry2 (NETIOAPI)
DeleteIpForwardEntry2 (NETIOAPI)
FreeMibTable (NETIOAPI)
GetBestRoute2 (NETIOAPI)
GetIpForwardEntry2 (NETIOAPI)
InitializeIpForwardEntry (NETIOAPI)
MIB_IPFORWARD_ROW2
MIB_IPFORWARD_TABLE2
NotifyRouteChange2 (NETIOAPI)
SetIpForwardEntry2 (NETIOAPI)