t_snddis

- send user-initiated disconnection request

Synopsis

#include <xti.h> 

int t_snddis(int fd, const struct t_call *call);

Description

This routine is part of the XTI interfaces which 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, the tiuser.h header file must be used. Refer to the TLI COMPATIBILITY section for a description of differences between the two interfaces.

This function is used to initiate an abortive release on an already established connection, or to reject a connection request. The argument fd identifies the local transport endpoint of the connection, and call specifies information associated with the abortive release. The argument call points to a t_call structure which contains the following members:

struct netbuf addr;
struct netbuf opt;
struct netbuf udata;
int sequence;

The values in call have different semantics, depending on the context of the call to t_snddis(). When rejecting a connection request, call must be non-null and contain a valid value of sequence to uniquely identify the rejected connection indication to the transport provider. The sequence field is only meaningful if the transport connection is in the T_INCON state. The addr and opt fields of call are ignored. In all other cases, call need only be used when data is being sent with the disconnection request. The addr, opt and sequence fields of the t_call structure are ignored. If the user does not wish to send data to the remote user, the value of call may be a null pointer.

The udata structure specifies the user data to be sent to the remote user. The amount of user data must not exceed the limits supported by the transport provider, as returned in the discon 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 remote user.

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

T_DATAXFER, T_OUTCON, T_OUTREL, T_INREL, T_INCON(ocnt > 0).

Errors

On failure, t_errno is set to one of the following:

TBADF

The specified file descriptor does not refer to a transport endpoint.

TBADDATA

The amount of user data specified was not within the bounds allowed by the transport provider.

TBADSEQ

An invalid sequence number was specified, or a null call pointer was specified, when rejecting a connection request.

TLOOK

An asynchronous event, which requires attention, has occurred.

TNOTSUPPORT

This function is not supported by the underlying transport provider.

TOUTSTATE

The communications endpoint referenced by fd 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).

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:

Error Description Values

The t_errno value TPROTO can be set by the XTI interface but not by the TLI interface.

Option Buffers

The format of the options in an opt buffer is dictated by the transport provider. Unlike the XTI interface, the TLI interface does not fix the buffer format.

Attributes

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

See Also

t_connect(3NSL), t_getinfo(3NSL), t_listen(3NSL), t_open(3NSL), t_snd(3NSL), attributes(5)

Warnings

t_snddis() is an abortive disconnection. Therefore a t_snddis() issued on a connection endpoint may cause data previously sent by means of t_snd(3NSL), or data not yet received, to be lost, even if an error is returned.