T_ACCEPT(3NSL) Networking Services Library Functions T_ACCEPT(3NSL)
NAME
t_accept - accept a connection request
SYNOPSIS
#include <xti.h>
int t_accept(
int fd,
int resfd,
const struct t_call *call);
DESCRIPTION
This routine is part of the
XTI interfaces that evolved from the
TLI interfaces.
XTI represents the future evolution of these interfaces.
However,
TLI interfaces are supported for compatibility. When using a
TLI routine that has the same name as an
XTI routine, a different
header file,
tiuser.h, must be used. Refer to the
TLI COMPATIBILITY section for a description of differences between the two interfaces.
This function is issued by a transport user to accept a connection
request. The parameter
fd identifies the local transport endpoint
where the connection indication arrived;
resfd specifies the local
transport endpoint where the connection is to be established, and
call contains information required by the transport provider to
complete the connection. The parameter
call points to a
t_call structure which contains the following members:
struct netbuf addr;
struct netbuf opt;
struct netbuf udata;
int sequence;
In
call,
addr is the protocol address of the calling transport user,
opt indicates any options associated with the connection,
udata points to any user data to be returned to the caller, and
sequence is
the value returned by
t_listen(3NSL) that uniquely associates the
response with a previously received connection indication. The
address of the caller,
addr may be null (length zero). Where
addr is
not null then it may optionally be checked by XTI.
A transport user may accept a connection on either the same, or on a
different, local transport endpoint than the one on which the
connection indication arrived. Before the connection can be accepted
on the same endpoint (
resfd==fd), the user must have responded to any
previous connection indications received on that transport endpoint
by means of
t_accept() or
t_snddis(3NSL). Otherwise,
t_accept() will
fail and set
t_errno to
TINDOUT.
If a different transport endpoint is specified (
resfd!=fd), then the
user may or may not choose to bind the endpoint before the
t_accept() is issued. If the endpoint is not bound prior to the
t_accept(), the
endpoint must be in the
T_UNBND state before the
t_accept() is
issued, and the transport provider will automatically bind it to an
address that is appropriate for the protocol concerned. If the
transport user chooses to bind the endpoint it must be bound to a
protocol address with a
qlen of zero and must be in the
T_IDLE state
before the
t_accept() is issued.
Responding endpoints should be supplied to
t_accept() in the state
T_UNBND. The call to
t_accept() may fail with t_errno set to
TLOOK if there
are indications (for example connect or disconnect) waiting to be
received on endpoint
fd. Applications should be prepared for such a
failure.
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(3NSL) or
t_getinfo(3NSL). If the
len field of
udata is zero, no data will be sent to the caller. All
the
maxlen fields are meaningless.
When the user does not indicate any option (
call->opt.len = 0) the
connection shall be accepted with the option values currently set for
the responding endpoint
resfd.
RETURN VALUES
Upon successful completion, a value of
0 is returned. Otherwise, a
value of -1 is returned and
t_errno is set to indicate an error.
VALID STATES
fd: T_INCON resfd (fd!=resfd): T_IDLE, T_UNBNDERRORS
On failure,
t_errno is set to one of the following:
TACCES The user does not have permission to accept a
connection on the responding transport endpoint or
to use the specified options.
TBADADDR The specified protocol address was in an incorrect
format or contained illegal information.
TBADDATA The amount of user data specified was not within the
bounds allowed by the transport provider.
TBADF The file descriptor
fd or
resfd does not refer to a
transport endpoint.
TBADOPT The specified options were in an incorrect format or
contained illegal information.
TBADSEQ Either an invalid sequence number was specified, or
a valid sequence number was specified but the
connection request was aborted by the peer. In the
latter case, its
T_DISCONNECT event will be
received on the listening endpoint.
TINDOUT The function was called with
fd==resfd but there are
outstanding connection indications on the endpoint.
Those other connection indications must be handled
either by rejecting them by means of
t_snddis(3NSL) or accepting them on a different endpoint by means
of
t_accept.
TLOOK An asynchronous event has occurred on the transport
endpoint referenced by
fd and requires immediate
attention.
TNOTSUPPORT This function is not supported by the underlying
transport provider.
TOUTSTATE The communications endpoint referenced by
fd or
resfd is not in one of the states in which a call to
this function is valid.
TPROTO This error indicates that a communication problem
has been detected between XTI and the transport
provider for which there is no other suitable XTI
error (
t_errno).
TPROVMISMATCH The file descriptors
fd and
resfd do not refer to
the same transport provider.
TRESADDR This transport provider requires both
fd and
resfd to be bound to the same address. This error results
if they are not.
TRESQLEN The endpoint referenced by
resfd (where
resfd !=
fd)
was bound to a protocol address with a
qlen that is
greater than zero.
TSYSERR A system error has occurred during execution of this
function.
TLI COMPATIBILITY
The
XTI and
TLI interface definitions have common names but use
different header files. This, and other semantic differences between
the two interfaces are described in the subsections below.
Interface Header
The
XTI interfaces use the header file,
xti.h.
TLI interfaces should
not use this header. They should use the header:
#include <tiuser.h>
Error Description Values
The
t_errno values that can be set by the
XTI interface and cannot be
set by the
TLI interface are:
TPROTO TINDOUT TPROVMISMATCH TRESADDR TRESQLEN Option Buffer
The format of the options in an
opt buffer is dictated by the
transport provider. Unlike the
XTI interface, the
TLI interface does
not specify the buffer format.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+---------------+-----------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------+
|MT Level | Safe |
+---------------+-----------------+
SEE ALSO
t_connect(3NSL),
t_getinfo(3NSL),
t_getstate(3NSL),
t_listen(3NSL),
t_open(3NSL),
t_optmgmt(3NSL),
t_rcvconnect(3NSL),
t_snddis(3NSL),
attributes(7)WARNINGS
There may be transport provider-specific restrictions on address
binding.
Some transport providers do not differentiate between a connection
indication and the connection itself. If the connection has already
been established after a successful return of
t_listen(3NSL),
t_accept() will assign the existing connection to the transport
endpoint specified by
resfd.
May 1, 1998 T_ACCEPT(3NSL)
