t_connect.3.man

This a separate release of the OpenSS7 X/Open XTI/TLI library, TLI modules (timod, tirdwr) and the I

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.\"
.\"
.\"
.\"
.TH T_CONNECT 3 "2004/05/16 02:35:36" "strxnet-0_9_2-4" "OpenSS7 XTI/TLI Library"
.\"
.\"
.SH NAME
.B t_connect
\- establish a transport connection
.\"
.\"
.SH SYNOPSIS
.PP
.B #include <xti.h>
.HP 8
.BI "int t_connect(int " fd ", struct t_call *" sndcall ", struct t_call *" rcvcall );
.\"
.\"
.SH ARGUMENTS
.PP
.TP
.I fd
the transport endpoint to connect.
.TP
.I sndcall
a pointer to a
.B t_call
structure specifying the peer address, options and data.
.TP
.I rcvcall
a pointer to a
.B t_call
structure returning the responding address, options and data.
.\"
.\"
.SH DESCRIPTION
.PP
.I fd
is the file descriptor of the local transport endpoint.
.PP
.I sndcall
is a
.B t_call
structure that specifies the address of the peer and the options and
connection data to send to the peer.
.PP
.I rcvcall
is a
.B t_call
structure that specifies the responding address, response options and
connection data received from the peer.
.PP
The
.IR sndcall " and " rcvcall
are
.B t_call
structures that specify the called and responding addresses.  The
.B t_call
structure is formated as follows:
.sp
.nf
\fC\s-1\
struct t_call {
        struct netbuf addr;             /* address */
        struct netbuf opt;              /* options */
        struct netbuf udata;            /* user data */
        int sequence;                   /* sequence number */
};
\fR\s+1
.fi
.TP
.I addr
is a
.BR netbuf (3)
structure specifying the area and length of the protocol address.
.I sndcall->addr
passes in on call the called address for the connection, if any.
.I sndcall->addr.len
is significant and
.I sndcall->addr.maxlen
is not.
.I rcvcall->addr
returns the responding address for the connection, if any.
.I rcvcall->addr.maxlen
is significant on call and
.I rcvcall->addr.len
is significant on return.
.TP
.I opt
is a
.BR netbuf (3)
structure specifying the area and length of the connection options.
.I sndcall->opt
passes in on call the local connection options.
.I sndcall->opt.len
is significant and
.I sndcall->opt.maxlen
is not.
.I rcvcall->opt
returns the remote connection options.
.I rcvcall->opt.maxlen
is significant on call and
.I rcvcall->opt.len
is significant on return.
.TP
.I udata
is a
.BR netbuf (3)
structure specifying the area and length of the connection data.
.I sndcall->udata
passes in on call the local connection data.
.I sndcall->udata.len
is significant and
.I sndcall->udata.maxlen
is not.
.I rcvcall->udata
returns the remote connection data.
.I rcvcall->udata.maxlen
is significant on call and
.I rcvcall->udata.len
is significant on return.
.TP
.I sequence
is not significant in the
.BR t_connect ()
call.
.\"
.\"
.SH OPTIONS
.PP
Options in the
.I sndcall->opt
and
.I rcvcall->opt
buffers are formatted as described in
.BR t_optmgmt (3).
.PP
Illegal options (where the
.I t_opthdr.len
exceeds the remaining size of the option buffer, or where the option value is
illegal)
cause
.BR t_connect ()
to either fail with
.IR t_errno (3)
set to
.RB [ TBADOPT ],
or the connection establishment to fail at a later stage, depending on when
the implementation detects the illegal option.
If multiple options are passed in
.I sndcall->opt
and on of them is illegal, the call fails.  It is possible, however, that some
or all of the submitted legal options were successfully negotiated.  Use the
.B T_CURRENT
management flag to
.BR t_optmgmt (3)
to establish which options were successful.
.PP
Options specified in
.I sndcall->opt
can address multiple option levels.
A legal option is ignored by
.BR t_connect ()
if it is for an option level unknown to the transport provider.  A legal
option is ignored by
.BR t_connect ()
if it is for an option name unsupported by (unknown to) the transport provider.
.PP
If a proposed value is an absolute requirement and the negotiated value is the
same, the returned option will have a status of
.BR T_SUCCESS .
If the option is supported and the negotiation is rejected, any attempt to
establish a connection aborts; a
.B T_DISCONNECT
event occurs, and a synchronous call to
.BR t_connect ()
fails with
.RB [ TLOOK ].
When multiple options are provided and one of them is rejected and the
connection establishment fails, one or all of the options successfully
negotiated before failure may retain their negotiated values.  Use
.BR t_optmgmt (3)
with the
.B T_CURRENT
flag to determine which options retains their negotiated values.
.PP
If a proposed value is not an absolute requirement, and the negotiated value
equals the proposed value, the returned option will have a status of
.BR T_SUCCESS .
If the negotiated value is of lesser quality than the proposed value, the
returned option will have a status of
.BR T_PARTSUCCESS .
If the option is not supported, it is quietly ignored.
.PP
.BR t_connect ()
initiates the negotiation of all options with end-to-end significance.
Options not explicitly specified in
.I sndcall->opt
are taken from an internal option buffer used by the transport provider that
contains the previously negotiated values or default values for the implicit
options of end-to-end significance.
.PP
If a transport user requests negotiation of a read-only option, or a
non-privileged user requests illegal access to a privileged option,
.BR t_connect ()
will either fail with
.RB [ TACCES ],
or the connection establishment aborts and a
.B T_DISCONNECT
event occurs.  If the connection aborts, a synchronous call to
.BR t_connect ()
fails with
.RB [ TLOOK ].
.PP
.BR t_connect ()
returns in
.I rcvcall->opt
the values of all options with end-to-end significance that were received with
the connection response and the negotiated values of those options without
end-to-end significance that had been specified in
.IR sndcall->opt .
However, options specified in
.I sndcall->opt
that are not supported or refer to an unknown option level are discarded and
not returned on output.  The status field of each option returned in
.I rcvcall->opt
indicates if the proposed value
.RB ( T_SUCCESS )
or a degraded value
.RB ( T_PARTSUCCESS )
has been negotiated.  The status field of received ancilliary information that is not
subject to negotiation is always set to
.BR T_SUCCESS .

.\"
.\"
.SH CAVEATS
.PP
.BR t_connect ()
is only valid in state
.BR T_IDLE .
.PP
In synchronous mode,
.BR t_connect ()
blocks until it successfully receives a connection confirmation.
In asynchronous mode (i.e.
.BR O_NONBLOCK " or " O_NDELAY
is set with
.BR t_open "(3) or " fcntl (2)),
.BR t_connect ()
will return immediately after failing to read a connection confirmation
with a a return value of -1 and
.IR t_errno (3)
set to
.BR T_NODATA .
.\"
.\"
.SH "RETURN VALUE"
.PP
Upon success,
.BR t_connect ()
returns zero (0), confirms the connection request and provides the responding
address, options and connection data in the
.I rcvcall
.B t_call
structure.
Upon failure,
.BR t_connect ()
returns -1 and sets
.IR t_errno (3)
to an appropriate error number.
.\"
.\"
.SH ERRORS
.PP
When
.BR t_connect ()
fails, it returns -1 and sets
.IR t_errno (3)
to an appropriate error number as follows:
.TP \w'[TNOTSUPPORT]\(em'u
.RB [ TACCES ]
The caller did not have sufficient permissions to use the address or options specified in
.IR sndcall->addr " or " sndcall->opt .
.TP
.RB [ TADDRBUSY ]
The
.I sndcall->addr
specificed was already in use by another transport endpoint.
.TP
.RB [ TBADADDR ]
The
.I sndcall->addr
specified was of an invalid format or contained invalid information.
.TP
.RB [ TBADDATA ]
The amount of data specified for the call
.I sndcall->udata.len
provider was invalid for the underlying transport service (i.e. was outside
the protocol limits).  See
.BR t_getinfo "(3) and " t_open (3)
for more information.
.TP
.RB [ TBADF ]
.I fd
is invalid.
.TP
.RB [ TBADOPT ]
The options specified were of an invalid format or contained invalid information.
See
.BR t_optmgmt (3)
for more information on option formats.
.TP
.RB [ TBUFOVFLW ]
The
.I maxlen
field of a
.BR netbuf (3)
structure,
.IR rcvcall->addr.maxlen ", " rcvcall->opt.maxlen " or " rcvcall->udata.maxlen ,
passed to the call was non-zero, but insufficient to hold the available opaque
information.  See,
.BR netbuf (3)
for more information.
.TP
.RB [ TLOOK ]
An asynchronous event occurred before the call could complete.  See
.BR t_look (3)
for more information.
.TP
.RB [ TNODATA ]
An attempt was made to read a connection confirmation but
.I fd
was set for non-blocking operation with
.BR O_NONBLOCK " or " O_NDELAY
and no connection confirmation was available.
The connection confirmation can be retrieved later with
.BR t_rcvconnect (3).
.TP
.RB [ TNOTSUPPORT ]
The call requires the use of a TLI primitive not supported by the underlying transport provider.
.TP
.RB [ TOUTSTATE ]
The call was issued with the interface in an incorrect state.
.TP
.RB [ TPROTO ]
A protocol error occurred between the XTI/TLI library and the underlying transport provider.
.TP
.RB [ TSYSERR ]
A
.B Linux
system error occurred and the
.B Linux
error number is set in
.IR errno (3).
.\"
.\"
.SH "SEE ALSO"
.PP
.BR fcntl (2),
.BR netbuf (3),
.BR t_errno (3),
.BR t_getinfo (3),
.BR t_look (3),
.BR t_open (3),
.BR t_rcvconnect (3).
.PP
.\"
.\"
.SH "BUGS"
.PP
.BR t_connect ()
has no known bugs.
.BR t_connect ()
has been tested for the described behaviour using the
.I /usr/bin/test-xnet
conformance test program.
.\"
.\"
.SH "CONFORMING TO"
.PP
XTI/TLI,
.[
XTI
.]
TPI,
.[
TPI Revision 2.0.0
.]
XPG5,
XNS 5.2,
.[
xns
.]
SUSv2.
.[
susv2
.]
.\"
.\"
.[
$LIST$
.]
.T4