Inside Macintosh: Open Transport /

Chapter 6 - Configuration Management / Configuration Management Reference

Constants and Data Types

The Port Structure

Open Transport uses a port structure to describe a port's characteristics, such as its port name, its child ports, whether it is active or disabled, whether it is private or sharable, and the kind of framing it can use.

The port structure is defined by the OTPortRecord data type.

struct OTPortRecord {
   OTPortRef   fRef;
   UInt32      fPortFlags;
   UInt32      fInfoFlags;
   UInt32      fCapabilities;
   size_t      fNumChildPorts;
   OTPortRef*  fChildPorts;
   char        fPortName[kMaxProviderNameSize];
   char        fModuleName[kMaxModuleNameSize];
   char        fSlotID[kMaxSlotIDSize];
   char        fResourceInfo[kMaxResourceInfoSize];
   char        fReserved[164];
};

Field Description

fRef

The port reference; a 32-bit value encoding the port's device type, bus type, slot number, and multiport identifier. For more details, see the next section, "The Port Reference."

fPortFlags

Flags describing the port's status. Only 1 bit can be set at a time. If no bits are set, the port is currently inactive--that is, it is not in use at this time.

Flag	Value	Description
kOTPortIsActive	0x00000001	The port is in use.
kOTPortIsDisabled	0x00000002	The port may or may not be in use, but no other client can use it.
kOTPortIsUnavailable	0x00000004	The port is not available for use.

fInfoFlags

Flags providing additional information about the port.

Flag	Value	Description
kOTPortIsDLPI	0x00000001	The port is a DLPI Streams module.
kOTPortIsTPI	0x00000002	The port is a TPI Streams module.
kOTPortCanYield	0x00000004	The port can yield when requested.
kOTPortIsSystemRegistered	0x00004000	The port is registered in the system registry.
kOTPortIsPrivate	0x00008000	The port is a private port.
kOTPortIsAlias	0x80000000	The port is an alias for another port.

fCapabilities

Flags indicating the type of framing capability that a port has. If the port can handle only one type of framing, this field is 0. For example, Ethernet framing uses the following values:

Flag	Value	Description
kOTFramingEthernet	0x01	The port can use standard Ethernet framing.
kOTFramingEthernetIPX	0x02	The port can use IPX Ethernet framing.
kOTFraming8023	0x04	The port can use 802.3 Ethernet framing.
kOTFraming8022	0x08	The port can use 802.2 Ethernet framing.

fNumChildPorts

The number of child ports associated with this port.

fChildPorts

An array of the port references for the child ports associated with this port.

fPortName

A unique name for this port. The port name is a zero-
terminated string that can have a maximum length as indicated by the constant kMaxProviderNameSize.

fModuleName

The name of the actual Streams module that implements the driver for this port. Open Transport uses this name internally; you do not use this name.

fSlotID

An 8-byte identifier for a port's slot that contains a 7-byte character string plus a zero for termination. This identifier is typically available for PCI cards.

fResourceInfo

A zero-terminated string that describes a shared library that can handle configuration information for the device. This field contains an identifier that allows Open Transport to access auxiliary information about your driver (Open Transport creates shared library IDs from this string to be able to find these extra shared libraries). This string should either be unique to your driver or should be set to a NULL string.

fReserved

Reserved.