Tribblix: manual page: t

T_BIND(3NSL) Networking Services Library Functions T_BIND(3NSL)

NAME

t_bind - bind an address to a tansport endpoint

SYNOPSIS

Network Services Library (libnsl, -lnsl)
#include <xti.h>

int
t_bind(int fd, const struct t_bind *req, stuct t_bind *ret);

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, 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 associates a protocol address with the transport endpoint
specified by fd and activates that transport endpoint. In connection
mode, the transport provider may begin enqueuing incoming connect
indications, or servicing a connection request on the transport
endpoint. In connectionless-mode, the transport user may send or
receive data units through the transport endpoint.

The req and ret arguments point to a t_bind structure containing the
following members:

struct netbuf addr;
unsigned qlen;

The addr field of the t_bind structure specifies a protocol address,
and the qlen field is used to indicate the maximum number of
outstanding connection indications.

The parameter req is used to request that an address, represented by
the netbuf structure, be bound to the given transport endpoint. The
parameter len specifies the number of bytes in the address, and buf
points to the address buffer. For tcp(4P) and udp(4P) transports, buf
points to a sockaddr(3SOCKET) buffer -- either struct sockaddr_in or
struct sockaddr_in6 (depending on if IPv4 or IPv6 is being used). The
parameter maxlen has no meaning for the req argument.

On return, ret contains an encoding for the address that the transport
provider actually bound to the transport endpoint; if an address was
specified in req, this will be an encoding of the same address. In
ret, the user specifies maxlen, which is the maximum size of the
address buffer, and buf which points to the buffer where the address is
to be placed. On return, len specifies the number of bytes in the
bound address, and buf points to the bound address. If maxlen equals
zero, no address is returned. If maxlen is greater than zero and less
than the length of the address, t_bind() fails with t_errno set to
TBUFOVFLW.

If the requested address is not available, t_bind() will return -1
with t_errno set as appropriate. If no address is specified in req
(the len field of addr in req is zero or req is NULL), the transport
provider will assign an appropriate address to be bound, and will
return that address in the addr field of ret. If the transport
provider could not allocate an address, t_bind() will fail with t_errno
set to TNOADDR.

The parameter req may be a null pointer if the user does not wish to
specify an address to be bound. Here, the value of qlen is assumed to
be zero, and the transport provider will assign an address to the
transport endpoint. Similarly, ret may be a null pointer if the user
does not care what address was bound by the provider and is not
interested in the negotiated value of qlen. It is valid to set req and
ret to the null pointer for the same call, in which case the provider
chooses the address to bind to the transport endpoint and does not
return that information to the user.

The qlen field has meaning only when initializing a connection-mode
service. It specifies the number of outstanding connection indications
that the transport provider should support for the given transport
endpoint. An outstanding connection indication is one that has been
passed to the transport user by the transport provider but which has
not been accepted or rejected. A value of qlen greater than zero is
only meaningful when issued by a passive transport user that expects
other users to call it. The value of qlen will be negotiated by the
transport provider and may be changed if the transport provider cannot
support the specified number of outstanding connection indications.
However, this value of qlen will never be negotiated from a requested
value greater than zero to zero. This is a requirement on transport
providers; see WARNINGS below. On return, the qlen field in ret will
contain the negotiated value.

If fd refers to a connection-mode service, this function allows more
than one transport endpoint to be bound to the same protocol address.
It is not possible to bind more than one protocol address to the same
transport endpoint. However, the transport provider must also support
this capability. If a user binds more than one transport endpoint to
the same protocol address, only one endpoint can be used to listen for
connection indications associated with that protocol address. In other
words, only one t_bind() for a given protocol address may specify a
value of qlen greater than zero. In this way, the transport provider
can identify which transport endpoint should be notified of an incoming
connection indication. If a user attempts to bind a protocol address
to a second transport endpoint with a value of qlen greater than zero,
t_bind() will return -1 and set t_errno to TADDRBUSY. When a user
accepts a connection on the transport endpoint that is being used as
the listening endpoint, the bound protocol address will be found to be
busy for the duration of the connection, until a t_unbind(3NSL) or
t_close(3NSL) call has been issued. No other transport endpoints may
be bound for listening on that same protocol address while that initial
listening endpoint is active (in the data transfer phase or in the
T_IDLE state). This will prevent more than one transport endpoint
bound to the same protocol address from accepting connection
indications.

If fd refers to connectionless mode service, this function allows for
more than one transport endpoint to be associated with a protocol
address, where the underlying transport provider supports this
capability (often in conjunction with value of a protocol-specific
option). If a user attempts to bind a second transport endpoint to an
already bound protocol address when such capability is not supported
for a transport provider, t_bind() will return -1 and set t_errno to
TADDRBUSY.

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_UNBND

ERRORS

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

TACCES The user does not have permission to use the
specified address.

TADDRBUSY The requested address is in use.

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

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

TBUFOVFLW The number of bytes allowed for an incoming argument
~ maxlen is greater than 0 but not sufficient to
store the value of that argument. The provider's
state will change to T_IDLE and the information to
be returned in ret will be discarded.

TOUTSTATE The communications endpoint referenced by fd is not
in one of the states in which a call to this
function is valid.

TNOADDR The transport provider could not allocate an
address.

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: <tiuser.h>

Address Bound

The user can compare the addresses in req and ret to determine whether
the transport provider bound the transport endpoint to a different
address than that requested.

Error Description Values

The t_errno values TPROTO and TADDRBUSY can be set by the XTI interface
but cannot be set by the TLI interface.

A t_errno value that this routine can return under different
circumstances than its XTI counterpart is TBUFOVFLW. It can be
returned even when the maxlen field of the corresponding buffer has
been set to zero.

MT-LEVEL
Safe

WARNINGS

The requirement that the value of qlen never be negotiated from a
requested value greater than zero to zero implies that transport
providers, rather than the XTI implementation itself, accept this
restriction.

An implementation need not allow an application explicitly to bind more
than one communications endpoint to a single protocol address, while
permitting more than one connection to be accepted to the same protocol
address. That means that although an attempt to bind a communications
endpoint to some address with qlen=0 might be rejected with TADDRBUSY,
the user may nevertheless use this (unbound) endpoint as a responding
endpoint in a call to t_accept(3NSL). To become independent of such
implementation differences, the user should supply unbound responding
endpoints to t_accept(3NSL).

The local address bound to an endpoint may change as result of a
t_accept(3NSL) or t_connect(3NSL) call. Such changes are not
necessarily reversed when the connection is released.

illumos September 28, 2017 illumos