n_data_req.7.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 N_DATA_REQ 7 "2004/05/16 02:35:46" "strxnet-0_9_2-4" "Network Provider Interface (NPI)"
.SH NAME
.BR N_DATA_REQ " (" N_data_req_t )
\- normal data transfer request
.SH SYNOPSIS
The format of the message is one or more
.B M_DATA
blocks.  Use of a
.B M_PROTO
message block is optional.
.PP
The structure of the
.B M_PROTO
message block, if present, is as follows:
.sp
.nf
\fC\s-1\
typedef struct {
    ulong PRIM_type;            /* always N_DATA_REQ */
    ulong DATA_xfer_flags;      /* bit masking for data xfer
                                   flags */
} N_data_req_t;

/* Data Transfer Flags */
#define N_MORE_DATA_FLAG    0x00000001L
#define N_RC_FLAG           0x00000002L
\fR\s+1
.fi
.SH DESCRIPTION
This user-originated primitive indicates to the NS provider that this message
contains NS user data.  It allows the transfer of NS user data between NS users,
without modification by the NS provider.  The NS user must send any integral
number of octets of data greater than zero.  In a case where the size of the
NSDU exceeds the NIDU (as specified by the size of the
.I NIDU_size
parameter of the
.BR N_INFO_ACK (7)
primitive), the NSDU may be broken up into more than one NIDU.  When an NSDU
is broken up into more than one NIDU, the
.B N_MORE_DATA_FLAG
will be set on each NIDU except the last one.  The
.B RC_flag
may only be set on the last NIDU.
.PP
The
.B M_PROTO
message block is used for two reasons:
.IP "i." 5
to indicate that the NSDU is broken into more than one NIDUs, and that the
data carried in the following
.B M_DATA
message block constitutes one NIDU;
.IP ii.
to indicate whether receipt confirmation is desired for the NSDU.  Guidelines
for use of
.BR M_PROTO :
The following guidelines must be followed with respect to the
use of the
.B M_PROTO
message block:
.RS
.IP "1." 4
The
.B M_PROTO
message block need not be present when the NSDU size is less than or equal to
the NIDU size and one of the following is true:
.RS
.IP \- 4
receipt confirmation has been negotiated for non-use (via the
.B N_CONN
primitives); or
.IP \-
receipt confirmation has been successfully negotiated for use or non-use
and the default selection as specified via the
.B N_OPTMGMT
primitive is to be used.
.RE
.IP 2.
The
.B M_PROTO
message block must be present when:
.RS
.IP \- 4
the NSDU size is greater than the NIDU size;
.IP \-
receipt confirmation has been successfully negotiated for use and the
default selection as specified via
.BR N_OPTMGMT_REQ (7)
primitive needs to be overridden.
.SH PARAMETERS
.TP
.I PRIM_type
Indicates the primitive type.

.TP
.I DATA_xfer_flags
.RS

.TP
.B N_MORE_DATA_FLAG
When set, the
.B MORE_DATA_FLAG indicates thatthe next
.B N_DATA_REQ
message (NIDU) is also part of this NSDU.

.TP
.B N_RC_FLAG
By setting this flag on the
.BR N_DATA_REQ ,
the originating NS user can request confirmation of receipt of the
.B N_DATA
primitive.  The receipt is provided by the
.B N_DATACK
primitives.  The parameter may only be present if use of Receipt Confirmation
was agreed by both NS users and the NS provider during NC establishment.
.SH STATE
This primitive is valid in the
.B NS_DATA_XFER
state.
.SH "NEW STATE"
The resulting state remains the same
.RB ( NS_DATA_XFER ).
.SH RESPONSE
This primitive does not require any acknowledgments, although it may generate
a fatal error.  This is indicated to the NS user via a
.B M_ERROR
.I STREAMS
message type (specifying an
.IR errno (3)
value of
.BR EPROTO )
which results in the failure of all system calls on that stream.
.SH ERRORS
The applicable errors are defined as follows:
.TP
.B [ EPROTO ]
This indicates one of the following unrecoverable protocol conditions:
.RS
.IP \- 4
The network interface was found to be in an incorrect state.
.IP \-
The amount of NS user data associated with the primitive is outside the range
supported by the NS provider (as specified by the
.I NIDU_size
parameter of
.BR N_INFO_ACK (7)
primitive).
.IP \-
The options requested are either not supported by the NS provider or its use
not specified with the
.BR N_CONN_REQ (7)
primitive.
.IP \-
The
.B M_PROTO
message block was not followed by one or more
.B M_DATA
message blocks.
.IP \-
The amount of NS user data associated with the current NSDU is outside the
range supported by the NS provider (as specified by the
.I NSDU_size
parameter in the
.BR N_INFO_ACK (7)
primitive.)
.IP \-
The
.B N_RC_FLAG
and
.B N_MORE_DATA_FLAG
were both set in the primitive, or the flags field contained an unknown value.
.RE
.PP
.B Note:
If the interface is in the
.B NS_IDLE
or
.B NS_WRES_RIND
states when the provider receives the
.B N_DATA_REQ
primitive, then the NS provider should discard the request without generating
a fatal error.
.SH "SEE ALSO"
.BR N_CONN_REQ (7),
.BR N_DATACK_IND (7),
.BR N_DATACK_REQ (7),
.BR N_DATA_IND (7),
.BR N_DATA_REQ (7),
.BR N_INFO_ACK (7)
.BR N_OPTMGMT_REQ (7),
.BR errno (3).
.SH HISTORY
.PP
The Network Provider Interface first appeared in SVR 4.
.[
svr4
.]
.SH CONFORMANCE
.PP
This interface conforms to NPI Revision 2.
.[
npi
.]
.XX
.[
magic
.]
.[
advprog
.]
.[
$LIST$
.]
.T2