Technical Reference: Communications, Volume 1

XID Data Received Routine for DLC

Purpose

Receives an exchange identification (XID) 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.rcvx_fa)( m, ext) struct mbuf *m; struct dlc_io_ext *ext;

Description

The DLC XID Data Received routine receives an XID packet each time the routine is coded by the kernel user and called by GDLC.

Parameters

m	Points to a communication 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 XID mbuf data has been accepted.
DLC_FUNC_RETRY	Indicates that the received XID mbuf data 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 may close the link station.

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

Related Information

read Subroutine Extended Parameters for DLC .

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