t_accept(NET)

Synopsis

#include <xti.h>

int t_accept(int fd, int resfd, struct t_call call)

Description

It may also be used to pass a connection to another endpoint.

This function is a service of connection-mode transport providers and is supported only if the provider returned service type T_COTS or T_COTS_ORD on t_open or t_getinfo.

A transport user may accept a connection on either the same or local transport endpoint or on an endpoint different than the one on which the connect indication arrived. Before the connection can be accepted on the same endpoint (resfd==fd), the user must have responded to any previous connect indications received on that endpoint (via t_accept or t_snddis). Otherwise, t_accept will fail and set t_errno to T_INDOUT.

If a different transport endpoint is specified (fd!=resfd), then the user may or may not choose to bind the endpoint before t_accept is issued. If the endpoint is not bound, then the transport provider will automatically bind it to the same protocol address that fd is bound to. If the user chooses to bind to a local address, then qlen must be zero for that protocol address, and the state of the endpoint must be T_IDLE. t_accept will change the address of resfd to be the same as that of fd. For portability, the first alternative is recommended.

Parameters

fd

the file descriptor for the local transport endpoint where the connect request arrived.

resfd

file descriptor for the local transport endpoint on which the connection is to be established.

call

points to the t_call structure used to complete the connection.

Structure definitions

   struct netbuf addr;     /* address            */
   struct netbuf opt;      /* options            */
   struct netbuf udata;    /* user data          */
   int sequence;           /* sequence number    */

The values of parameters specified by opt and the syntax of those values are protocol specific. The udata argument enables the called transport user to send user data to the caller and the amount of user data must not exceed the limits supported by the transport provider as returned in the ``connect'' field of the info argument of t_open or t_getinfo. If the ``len'' field of udata is 0, no data will be sent to the caller.

State transitions

fd

T_INCON on entry. T_INCON, T_IDLE or T_DATAXFER on exit.

resfd

T_IDLE, T_UNBND on entry.

Files

/usr/lib/libxti.so

X/Open^® Transport Interface Library (shared object)

/usr/lib/libnsl.so

Network Services Library (shared object)

Usage

A server application may retry t_accept unless a TOUTSTATE or TSYSERR error is received.

If the user does not specify protocol-specific options (the ``len'' field of opt is 0), it is assumed that the connection should accepted unconditionally. Options other than the defaults may be selected by the transport provider to ensure that the connection is accepted successfully.

Return values

Errors

TBADF

The specified file descriptor does not refer to a transport endpoint, or the user is invalidly accepting a connection on the same transport endpoint on which the connect indication arrived.

TOUTSTATE

The function was issued in the wrong sequence on the transport endpoint referenced by fd, or the transport endpoint referred to by resfd is not in the T_IDLE state.

TACCES

The user does not have permission to accept a connection on the responding transport endpoint or use the specified options.

TBADOPT

The specified options were in an incorrect format or contained invalid information.

TBADDATA

The amount of user data specified was not within the bounds supported by the transport provider as returned in the ``connect'' field of the info argument of t_open or t_getinfo.

TBADSEQ

An invalid sequence number was specified.

TBADADDR

The specified protocol address was in an incorrect format or contained illegal information.

TLOOK

An asynchronous event has occurred on the transport endpoint referenced by fd and requires immediate attention. t_accept will fail and set t_errno to TLOOK when fd is not the same as resfd and there are indications (for example, a connect or disconnect) waiting to be received on that endpoint.

TNOTSUPPORT

This function is not supported by the underlying transport provider.

TSYSERR

A system error has occurred during execution of this function.

TINDOUT

The function was called with fd equal to resfd but there are outstanding connection indications on the endpoint. The other connection indications must be handled either by rejecting them via t_snddis or accepting them via t_accept.

TPROVMISMATCH

The file descriptors fd and resfd do not refer to the same transport provider.

TRESQLEN

The endpoint referenced by resfd where resfd!=fd was bound to a protocol address with a qlen greater than 0.

TRESADDR

This transport provider requires that both fd and resfd be bound to the same address.

TPROTO

A communication problem has been detected with the transport provider and there is no other value of t_errno to describe the error condition.

References