Legacy Document

Inside Macintosh: Networking With Open Transport / Part 2 - Open Transport Reference

Chapter 26 - Ports 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 shareable, 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];
};
typedef struct OTPortRecord OTPortRecord;

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.

fPortFlags

Flags describing the port's status. 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.
kOTPortIsOffline	0x00000008	The port is off-line. This bit is typically only set when the port is active, the port autoconnects, and it is currently not connected.

fInfoFlags

Flags providing additional information about the port.

Flag	Value	Description
kOTPortIsDLPI	0x00000001	The port driver is a DLPI STREAMS module.
kOTPortIsTPI	0x00000002	The port driver is a TPI STREAMS module.
kOTPortCanYield	0x00000004	The port can yield when requested.
kOTPortCanArbitrate	0x00000008	Reserved
kOTPortIsTransitory	0x00000010	The port has off-line/on-line status.
kOTPortAutoConnects	0x00000020	The port auto connects. The port goes on-line and off-line on demand. ISDN is a typical example.
kOTPortIsSystemRegistered	0x00004000	The port was registered by the system from the Name 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. This field is dependent on the ports device type. 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. When you get a Port Record, this pointer typically points into the SReserved field at the end of the record.

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; applications rarely need to 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 only 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 the 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 the driver or should be set to a NULL string.

fReserved

Reserved.