Networking Services Library Functions topen(3NSL)
NAME
topen - establish a transport endpoint
SYNOPSIS
#include
#include
int topen(const char *name, int oflag, struct tinfo *info);
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.
The topen() function must be called as the first step in
the initialization of a transport endpoint. This function
establishes a transport endpoint by supplying a transport
provider identifier that indicates a particular transport
provider, that is, transport protocol, and returning a file
descriptor that identifies that endpoint.
The argument name points to a transport provider identifier
and oflag identifies any open flags, as in open(2). The
argument oflag is constructed from ORDWR optionally bit-
wise inclusive-OR'ed with ONONBLOCK. These flags are
defined by the header . The file descriptor
returned by topen() will be used by all subsequent func-
tions to identify the particular local transport endpoint.
This function also returns various default characteristics
of the underlying transport protocol by setting fields in
the tinfo structure. This argument points to a tinfo which
contains the following members:
tscalart addr; /* max size of the transport protocol address */
tscalart options; /* max number of bytes of */
/* protocol-specific options */
tscalart tsdu; /* max size of a transport service data */
/* unit (TSDU) */
tscalart etsdu; /* max size of an expedited transport */
/* service data unit (ETSDU) */
SunOS 5.11 Last change: 7 May 1998 1
Networking Services Library Functions topen(3NSL)
tscalart connect; /* max amount of data allowed on */
/* connection establishment functions */
tscalart discon; /* max amount of data allowed on */
/* tsnddis() and trcvdis() functions */
tscalart servtype; /* service type supported by the */
/* transport provider */
tscalart flags; /* other info about the transport provider */
The values of the fields have the following meanings:
addr A value greater than zero (TNUL) indicates the
maximum size of a transport protocol address and
a value of -2 (TINVALID) specifies that the
transport provider does not provide user access
to transport protocol addresses.
options A value greater than zero (TNUL) indicates the
maximum number of bytes of protocol-specific
options supported by the provider, and a value
of -2 (TINVALID) specifies that the transport
provider does not support user-settable options.
tsdu A value greater than zero (TNUL specifies the
maximum size of a transport service data unit
(TSDU); a value of zero (TNUL) specifies that
the transport provider does not support the con-
cept of TSDU, although it does support the send-
ing of a data stream with no logical boundaries
preserved across a connection; a value of -1
(TINFINITE) specifies that there is no limit to
the size of a TSDU; and a value of -2
(TINVALID) specifies that the transfer of nor-
mal data is not supported by the transport pro-
vider.
etsdu A value greater than zero (TNUL) specifies the
maximum size of an expedited transport service
data unit (ETSDU); a value of zero (TNUL)
specifies that the transport provider does not
support the concept of ETSDU, although it does
support the sending of an expedited data stream
with no logical boundaries preserved across a
connection; a value of -1 (TINFINITE) speci-
fies that there is no limit on the size of an
ETSDU; and a value of -2 (TINVALID) specifies
that the transfer of expedited data is not sup-
ported by the transport provider. Note that the
SunOS 5.11 Last change: 7 May 1998 2
Networking Services Library Functions topen(3NSL)
semantics of expedited data may be quite dif-
ferent for different transport providers.
connect A value greater than zero (TNUL) specifies the
maximum amount of data that may be associated
with connection establishment functions, and a
value of -2 (TINVALID) specifies that the tran-
sport provider does not allow data to be sent
with connection establishment functions.
discon If the TORDRELDATA bit in flags is clear, a
value greater than zero (TNUL) specifies the
maximum amount of data that may be associated
with the tsnddis(3NSL) and trcvdis(3NSL) func-
tions, and a value of -2 (TINVALID) specifies
that the transport provider does not allow data
to be sent with the abortive release functions.
If the TORDRELDATA bit is set in flags, a
value greater than zero (TNUL) specifies the
maximum number of octets that may be associated
with the tsndreldata(), trcvreldata(),
tsnddis(3NSL) and trcvdis(3NSL) functions.
servtype This field specifies the service type supported
by the transport provider, as described below.
flags This is a bit field used to specify other infor-
mation about the communications provider. If
the TORDRELDATA bit is set, the communications
provider supports user data to be sent with an
orderly release. If the TSENDZERO bit is set
in flags, this indicates the underlying tran-
sport provider supports the sending of zero-
length TSDUs.
If a transport user is concerned with protocol independence,
the above sizes may be accessed to determine how large the
buffers must be to hold each piece of information. Alterna-
tively, the talloc(3NSL) function may be used to allocate
these buffers. An error will result if a transport user
exceeds the allowed data size on any function.
The servtype field of info specifies one of the following
values on return:
SunOS 5.11 Last change: 7 May 1998 3
Networking Services Library Functions topen(3NSL)
TCOTS The transport provider supports a
connection-mode service but does not support
the optional orderly release facility.
TCOTSORD The transport provider supports a
connection-mode service with the optional
orderly release facility.
TCLTS The transport provider supports a
connectionless-mode service. For this service
type, topen() will return -2 (TINVALID) for
etsdu, connect and discon.
A single transport endpoint may support only one of the
above services at one time.
If info is set to a null pointer by the transport user, no
protocol information is returned by topen().
RETURN VALUES
A valid file descriptor is returned upon successful comple-
tion. Otherwise, a value of -1 is returned and terrno is
set to indicate an error.
VALID STATES
TUNINIT.
ERORS
On failure, terrno is set to the following:
TBADFLAG An invalid flag is specified.
TBADNAME Invalid transport provider name.
TPROTO This error indicates that a communication prob-
lem has been detected between XTI and the tran-
sport provider for which there is no other suit-
able XTI error (terrno).
TSYSER A system error has occurred during execution of
this function.
SunOS 5.11 Last change: 7 May 1998 4
Networking Services Library Functions topen(3NSL)
TLI COMPATIBILITY
The XTI and TLI interface definitions have common names but
use different header files. This and other semantic differ-
ences between the two interfaces are described in the sub-
sections below.
Interface Header
The XTI interfaces use the xti.h TLI interfaces should not
use this header. They should use the header:
#include
Error Description Values
The terrno values TPROTO and TBADNAME can be set by the XTI
interface but cannot be set by the TLI interface.
Notes
For TLI , the tinfo structure referenced by info lacks the
following structure member:
tscalart flags; /* other info about the transport provider */
This member was added to struct tinfo in the XTI inter-
faces.
When a value of -1 is observed as the return value in vari-
ous tinfo structure members, it signifies that the tran-
sport provider can handle an infinite length buffer for a
corresponding attribute, such as address data, option data,
TSDU (octet size), ETSDU (octet size), connection data, and
disconnection data. The corresponding structure members are
addr, options, tsdu, estdu, connect, and discon, respec-
tively.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
MT Level Safe
SEE ALSO
open(2), attributes(5)
SunOS 5.11 Last change: 7 May 1998 5
|
