dat_cr_accept

- establishes a Connection between the active remote side requesting Endpoint and the passive side local Endpoint

Synopsis

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

DAT_RETURN
    dat_cr_accept (
    IN    DAT_CR_HANDLE    cr_handle,
    IN    DAT_EP_HANDLE    ep_handle,
    IN    DAT_COUNT        private_data_size,
    IN const DAT_PVOID     private_data
    )

Parameters

cr_handle

Handle to an instance of a Connection Request that the Consumer is accepting.

ep_handle

Handle for an instance of a local Endpoint that the Consumer is accepting the Connection Request on. If the local Endpoint is specified by the Connection Request, the ep_handle shall be DAT_HANDLE_NULL.

private_data_size

Size of the private_data, which must be nonnegative.

private_data

Pointer to the private data that should be provided to the remote Consumer when the Connection is established. If private_data_size is zero, then private_data can be NULL.

Description

The dat_cr_accept() function establishes a Connection between the active remote side requesting Endpoint and the passive side local Endpoint. The local Endpoint is either specified explicitly by ep_handle or implicitly by a Connection Request. In the second case, ep_handle is DAT_HANDLE_NULL.

Consumers can specify private data that is provided to the remote side upon Connection establishment.

If the provided local Endpoint does not satisfy the requested Connection Request, the operation fails without any effect on the local Endpoint, Pending Connection Request, private data, or remote Endpoint.

The operation is asynchronous. The successful completion of the operation is reported through a Connection Event of type DAT_CONNECTION_EVENT_ESTABLISHED on the connect_evd of the local Endpoint.

If the Provider cannot complete the Connection establishment, the connection is not established and the Consumer is notified through a Connection Event of type DAT_CONNECTION_EVENT_ACCEPT_COMPLETION_ERROR on the connect_evd of the local Endpoint. It can be caused by the active side timeout expiration, transport error, or any other reason. If Connection is not established, Endpoint transitions into Disconnected state and all posted Recv DTOs are flushed to its recv_evd_handle.

This operation, if successful, also destroys the Connection Request instance. Use of the handle of the destroyed cr_handle in any consequent operation fails.

Return Values

DAT_SUCCESS

The operation was successful.

DAT_INVALID_HANDLE

The cr_handle or ep_handle parameter is invalid.

DAT_INVALID_PARAMETER

The private_data_size or private_data parameter is invalid, out of range, or a combination of parameters was invalid

Usage

Consumers should be aware that Connection establishment might fail in the following cases: If the accepting Endpoint has an outstanding RDMA Read outgoing attribute larger than the requesting remote Endpoint or outstanding RDMA Read incoming attribute, or if the outstanding RDMA Read incoming attribute is smaller than the requesting remote Endpoint or outstanding RDMA Read outgoing attribute.

Consumers should set the accepting Endpoint RDMA Reads as the target (incoming) to a number larger than or equal to the remote Endpoint RDMA Read outstanding as the originator (outgoing), and the accepting Endpoint RDMA Reads as the originator to a number smaller than or equal to the remote Endpoint RDMA Read outstanding as the target. DAT API does not define a protocol on how remote peers exchange Endpoint attributes. The exchange of outstanding RDMA Read incoming and outgoing attributes of EPs is left to the Consumer ULP. Consumer can use Private Data for it.

If the Consumer does not care about posting RDMA Read operations or remote RDMA Read operations on the connection, it can set the two outstanding RDMA Read attribute values to 0.

If the Consumer does not set the two outstanding RDMA Read attributes of the Endpoint, the Provider is free to pick up any value for default. The Provider can change these default values during connection setup.

Attributes

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

See Also

libdat(3LIB), attributes(5)