.\"
.\" Copyright (c) 2004-2005
.\"	Hartmut Brandt.
.\" 	All rights reserved.
.\" Copyright (c) 2001-2003
.\"	Fraunhofer Institute for Open Communication Systems (FhG Fokus).
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.\" Author: Hartmut Brandt <harti@FreeBSD.org>
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.\" $Begemot: libunimsg/man/unistruct.3,v 1.5 2005/06/15 11:37:12 brandt_h Exp $
.\"
.Dd May 23, 2005
.Dt UNISTRUCT 3
.Os
.Sh NAME
.Nm libngatm
.Nd "ATM signalling library"
.Sh LIBRARY
Begemot ATM signalling library
.Pq libngatm, -lngatm
.Sh SYNOPSIS
.In netnatm/msg/unistruct.h
.In netnatm/msg/unimsglib.h
.Sh DESCRIPTION
The
.Nm
library handles UNI 4.0 messages.
For each information element and message
type the header files contain a structure definition.
Additionally there
are a number of help structures and a global context structure for some
of the library functions.
This document only describes the common structures.
For information element and message structures see the header files.
.Ss LIBRARY CONFIGURATION
When the library is compiled a number of constants are define in the file
.Pa uni_config.h .
They define certain limits.
Because of the use of these definitions a change
in any of them requires a complete recompilation of all library code and
all code that uses the library.
The following constants are defined (they
value behind the name is the default value):
.Bl -tag -width XXXX
.It Dv UNI_MAX_ERRIE ( Li 50 )
When decoding information elements and analyzing them the library fills
an array in the context with the identifiers of IEs that had errors.
This is the size of this array.
.It Dv UNI_NUM_IE_GIT ( Li 3 )
A message is allowed to contain more than one General Identifier Transport
information element.
This is the maximum supported number of these IEs.
.It Dv UNI_NUM_IE_BLLI ( Li 3 )
The maximum number of BLLI information elements in a SETUP message.
.It Dv UNI_NUM_IE_CALLEDSUB ( Li 2 )
The maximum number of Called Subaddress information elements in a SETUP message.
.It Dv UNI_NUM_IE_CALLINGSUB ( Li 2 )
The maximum number of Calling Subaddress information elements in a SETUP
message.
.It Dv UNI_NUM_IE_TNS ( Li 4 )
The maximum number of Transit Network Selection information elements in a SETUP
message.
.It Dv UNI_TNS_MAXLEN ( Li 4 )
The maximum size of a name in the TNS IE.
.It Dv UNI_UU_MAXLEN ( Li 128 )
Maximum size of user data in the UU IE.
.It Dv UNI_ADDR_MAXLEN ( Li 20 )
Maximum address size.
.It Dv UNI_SUBADDR_MAXLEN ( Li 20 )
Maximum subaddress size.
.It Dv UNI_NUM_IE_DTL ( Li 10 )
Maximum number of DTL information elements in a SETUP message.
.It Dv UNI_DTL_MAXNUM ( Li 20 )
Maximum number of identifiers in one DTL information element.
.El
.Ss INFORMATION ELEMENTS
Each information element structure starts with a field of type:
.Bd -literal -offset indent
struct uni_iehdr {
	enum uni_coding	coding;	/* coding standard */
	enum uni_ieact	act;	/* action indicator */
	u_int		pass:1;	/* PNNI pass along request */
	u_int		present;/* which optional elements are present */
};
.Ed
.Pp
The
.Fa coding
field is the coding standard of the information element and may be one of
.Dv UNI_CODING_ITU
or
.Dv UNI_CODING_NET .
The action indicator
.Fa act
is used for error processing and is one of:
.Bl -tag -width XXXX
.It Dv UNI_IEACT_CLEAR
clear call
.It Dv UNI_IEACT_IGNORE
ignore IE and proceed
.It Dv UNI_IEACT_REPORT
ignore IE, report and proceed
.It Dv UNI_IEACT_MSG_IGNORE
ignore message
.It Dv UNI_IEACT_MSG_REPORT
ignore message and report
.It Dv UNI_IEACT_DEFAULT
the use action indicator flag was not set.
.El
.Pp
For information elements in PNNI message the
.Fa pass
fields contains the pass along flag from the IE header.
.Pp
The
.Fa present
field is a bit field, which contains four common bits describing the current
state of the information element.
The rest of the bits are used by the
information elements to indicate which of the optional fields of the IE are
present.
Most of the IE header files contain definitions for those bits.
The common bits are:
.Bd -literal -offset indent
#define UNI_IE_EMPTY	0x80000000
#define UNI_IE_PRESENT	0x40000000
#define UNI_IE_ERROR	0x20000000
#define UNI_IE_XXX	0x10000000
.Ed
.Pp
The flag
.Dv UNI_IE_EMPTY
indicates that the information element is present, but empty (its length is
zero).
This is legal for all information elements.
The flag
.Dv UNI_IE_PRESENT
indicates that the IE is present in the message and the flag
.Dv UNI_IE_ERROR
indicates that the IE had an error.
The flag
.Dv UNI_IE_XXX
is currently not used.
.Pp
The following macros may be used to test or change these flags:
.Bl -tag -width XXXX
.It Dv IE_ISPRESENT
Check whether the IE is present and not empty.
Returns true in this case.
.It Dv IE_SETPRESENT
Set the IE to be present and not empty.
.It Dv IE_ISEMPTY
Check whether the IE is present and empty.
Returns true in this case.
.It Dv IE_SETEMPTY
Set the IE to be present and empty.
.It Dv IE_ISERROR
Check whether the IE is present and has an error.
Returns true in this case.
.It Dv IE_SETERROR
Sets the IE to be present and to have an error.
.It Dv IE_ISGOOD
Checks whether the IE is present, not empty and without error.
Returns true in this case.
.El
.Pp
For each IE type there is an
.Vt enum uni_ietype
definition of the form
.Dv UNI_IE_*
in
.Pa uni_hdr.h .
.Pp
.Pa unistruct.h
contains a
.Vt union uni_ieall
that is the union of all IE structures and a
.Bd -literal -offset indent
struct uni_ie {
	enum uni_ietype		ietype;
	union uni_ieall		u;
};
.Ed
.Ss MESSAGES
Each message structure starts with a
.Bd -literal -offset indent
struct uni_msghdr {
	struct uni_cref	cref;
	enum uni_msgact	act;	/* action indicator */
	u_int		pass:1;	/* PNNI pass along request */
};
.Ed
.Pp
The
.Fa cref
is the call reference:
.Bd -literal -offset indent
struct uni_cref {
	u_int	flag;
	u_int	cref;
};
.Ed
.Pp
There are two special call references:
.Dv CREF_GLOBAL
and
.Dv CREF_DUMMY .
The
.Fa act
field is the message action indicator and has one of the following values:
.Bl -tag -width XXXX
.It Dv UNI_MSGACT_CLEAR
clear call
.It Dv UNI_MSGACT_IGNORE
ignore message
.It Dv UNI_MSGACT_REPORT
send STATUS message
.It Dv UNI_MSGACT_DEFAULT
default handling for this message type
.El
.Pp
The
.Fa pass
field is the pass along indicator in the case of PNNI messages.
.Pp
For each message type there is a
.Vt enum uni_msgtype
definition of the form
.Dv UNI_*
in
.Pa uni_hdr.h .
.Pa uni_struct.h
contains a
.Vt union_msgall
that is the union of all message structures and a
.Bd -literal -offset indent
struct uni_all {
	enum uni_msgtype	mtype;
	union uni_msgall	u;
};
.Ed
.Ss CONTEXTS
The header file
.Pa unimsglib.h
contains a definition of a
.Vt struct uni_context
that is used to minimize the number of arguments passed to certain functions
and to avoid the use of global variables.
This structure has the following
public fields (all other fields are used internally by the library):
.Bl -tag -width XXXX
.It Fa err
This is an array consisting of the following structures:
.Bd -literal -offset indent
struct uni_ierr {
	enum uni_ierr_type err;	/* what error */
	enum uni_ieact	act;	/* the action indicator */
	u_int		ie:8;	/* the ie type */
	u_int		man:1;	/* mandatory flag */
	u_int		epref:1;/* Q.2971 9.5.3.2.1 low-pri epref */
};
.Ed
When decoding information elements the information about IEs with errors is
stuffed into this array.
.It Fa errcnt
The current number of IEs in
.Fa err .
.It Fa q2932
Enable the Q.2932.1 Generic Functional Protocol.
Currently only message
and IE decoding/encoding is supported.
The signalling part is still missing.
.It Fa pnni
Enable PNNI extensions.
Currently only message and IE decoding/encoding
is supported.
The signalling part is still missing.
.It Fa git_hard
Do hard checking on GIT information elements.
.It Fa bearer_hard
Do hard checking on Broadband Bearer IEs.
This involves rejecting old bearer
type values.
.It Fa cause_hard
Do hard checking on Cause information elements.
.It Fa multiline
This is used by the printing routines.
Legal values are 0 to 4 and give
different kinds of printout.
.It Fa tabsiz
The size of tabulation to use in printing.
4 is a good value.
.El
.Sh SEE ALSO
.Xr libunimsg 3
.Sh STANDARDS
This implementation conforms to the applicable ITU-T
recommendations and ATM Forum standards with the exception of some limitations
(see the Configuration section).
.Sh AUTHORS
.An Hartmut Brandt Aq harti@FreeBSD.org