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Technical Reference: Communications, Volume 1


I-Frame Data Received Routine for DLC

Purpose

Receives a normal sequenced data packet each time it is coded by the kernel user and called by generic data link control (GDLC).

Syntax

#include <sys/gdlextcb.h>


int (*dlc_open_ext.rcvi_fa)( m, ext)
struct mbuf *m;
struct dlc_io_ext *ext;

Description

The DLC I-Frame Data Received routine receives a normal sequenced data packet each time it is coded by the kernel user and called by GDLC.

Parameters


m Points to a communications memory buffer (mbuf).
ext Specifies the receive extension parameter. This is a pointer to the dlc_io_ext extended I/O structure for reads. The argument to this parameter must be in the kernel space.

Return Values


DLC_FUNC_OK Indicates that the received I-frame function call is accepted.
DLC_FUNC_BUSY Indicates that the received I-frame function call cannot be accepted at this time. The ioctl command operation DLC_EXIT_LBUSY must be issued later using the ioctl subroutine.
DLC_FUNC_RETRY Indicates that the received I-frame function call cannot be accepted at this time. GDLC should retry this function call later. The actual retry wait period depends on the DLC in use. Excessive retries can be subject to a halt of the link station.

Implementation Specifics

Each GDLC supports a subset of the data-received routines. It is critical to performance that the I-Frame Data Received routine be coded to minimize the amount of time spent prior to returning to the GDLC that called it.

Related Information

The ioctl subroutine.

Parameter Blocks by ioctl Operation for DLC .

read Subroutine Extended Parameters for DLC .

Generic Data Link Control (GDLC) Environment Overview in AIX 5L Version 5.1 Communications Programming Concepts.


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