dat_psp_create

- create a persistent Public Service Point

Synopsis

cc [ flag… ] file… -ldat [ library… ] 
#include <dat/udat.h>

DAT_RETURN
    dat_psp_create(
    IN    DAT_IA_HANDLE    ia_handle,
    IN    DAT_CONN_QUAL    conn_qual,
    IN    DAT_EVD_HANDLE   evd_handle,
    IN    DAT_PSP_FLAGS    psp_flags,
    OUT   DAT_PSP_HANDLE   *psp_handle
    )

Parameters

ia_handle

Handle for an instance of DAT IA.

conn_qual

Connection Qualifier of the IA on which the Public Service Point is listening.

evd_handle

Event Dispatcher that provides the Connection Requested Events to the Consumer. The size of the event queue for the Event Dispatcher controls the size of the backlog for the created Public Service Point.

psp_flags

Flag that indicates whether the Provider or Consumer creates an Endpoint per arrived Connection Request. The value of DAT_PSP_PROVIDER indicates that the Consumer wants to get an Endpoint from the Provider; a value of DAT_PSP_CONSUMER means the Consumer does not want the Provider to provide an Endpoint for each arrived Connection Request.

psp_handle

Handle to an opaque Public Service Point.

Description

The dat_psp_create() function creates a persistent Public Service Point that can receive multiple requests for connection and generate multiple Connection Request instances that are delivered through the specified Event Dispatcher in Notification events.

The dat_psp_create() function is blocking. When the Public Service Point is created, DAT_SUCCESS is returned and psp_handle contains a handle to an opaque Public Service Point Object.

There is no explicit backlog for a Public Service Point. Instead, Consumers can control the size of backlog through the queue size of the associated Event Dispatcher.

The psp_flags parameter allows Consumers to request that the Provider create an implicit Endpoint for each incoming Connection Request, or request that the Provider should not create one per Connection Request. If the Provider cannot satisfy the request, the operation shall fail and DAT_MODEL_NOT_SUPPORTED is returned.

All Endpoints created by the Provider have DAT_HANDLE_NULL for the Protection Zone and all Event Dispatchers. The Provider sets up Endpoint attributes to match the Active side connection request. The Consumer can change Endpoint parameters. Consumers should change Endpoint parameters, especially PZ and EVD, and are advised to change parameters for local accesses prior to the connection request acceptance with the Endpoint.

Return Values

DAT_SUCCESS

The operation was successful.

DAT_INSUFFICIENT_RESOURCES

The operation failed due to resource limitations.

DAT_INVALID_HANDLE

The ia_handle or evd_handle parameter is invalid.

DAT_INVALID_PARAMETER

The conn_qual or psp_flags parameter is invalid.

DAT_CONN_QUAL_IN_USE

The specified Connection Qualifier was in use.

DAT_MODEL_NOT_SUPPORTED

The requested Model was not supported by the Provider.

Usage

Two uses of a Public Service Point are as follows:

Model 1

For this model, the Provider manipulates a pool of Endpoints for a Public Service Point. The Provider can use the same pool for more than one Public Service Point.

• The DAT Consumer creates a Public Service Point with a flag set to DAT_PSP_PROVIDER.

• The Public Service Point does the following:

  • Collects native transport information reflecting a received Connection Reques

  • Creates an instance of Connection Reques

  • Creates a Connection Request Notice (event) that includes the Connection Request instance (thatwhich includes, among others, Public Service Point, its Connection Qualifier, Provider-generated Local Endpoint, and information about remote Endpoint)

  • Delivers the Connection Request Notice to the Consumer-specified target (CNO) evd_handle

    The Public Service Point is persistent and continues to listen for incoming requests for connection.

• Upon receiving a connection request, or at some time subsequent to that, the DAT Consumer can modify the provided local Endpoint to match the Connection Request and must either accept() or reject() the pending Connection Request.

• If accepted, the provided Local Endpoint is now in a "connected" state and is fully usable for this connection, pending only any native transport mandated RTU (ready-to-use) messages. This includes binding it to the IA port if that was not done previously. The Consumer is notified that the Endpoint is in Connected state by a Connection Established Event on the Endpoint connect_evd_handle.

• If rejected, control of the Local Endpoint point is returned back to the Provider and its ep_handle is no longer usable by the Consumer.

Model 2

For this model, the Consumer manipulates a pool of Endpoints. Consumers can use the same pool for more than one Service Point.

• DAT Consumer creates a Public Service Point with a flag set to DAT_PSP_CONSUMER.

• Public Service Point:

  • Collects native transport information reflecting a received Connection Request

  • Creates an instance of Connection Request

  • Creates a Connection Request Notice (event) that includes the Connection Request instance (which includes, among others, Public Service Point, its Connection Qualifier, Provider-generated Local Endpoint and information about remote Endpoint)

  • Delivers the Connection Request Notice to the Consumer-specified target (CNO) evd_handle

    The Public Service Point is persistent and continues to listen for incoming requests for connection.

• The Consumer creates a pool of Endpoints that it uses for accepting Connection Requests. Endpoints can be created and modified at any time prior to accepting a Connection Request with that Endpoint.

• Upon receiving a connection request or at some time subsequent to that, the DAT Consumer can modify its local Endpoint to match the Connection Request and must either accept() or reject() the pending Connection Request.

• If accepted, the provided Local Endpoint is now in a "connected" state and is fully usable for this connection, pending only any native transport mandated RTU messages. This includes binding it to the IA port if that was not done previously. The Consumer is notified that the Endpoint is in Connected state by a Connection Established Event on the Endpoint connect_evd_handle.

• If rejected, the Consumer does not have to provide any Endpoint for dat_cr_reject(3DAT).

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

dat_cr_reject(3DAT), libdat(3LIB), attributes(5)