253 lines
8.4 KiB
Groff
253 lines
8.4 KiB
Groff
.\"
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.\" Copyright (c) 2001-2003
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.\" Fraunhofer Institute for Open Communication Systems (FhG Fokus).
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.\" All rights reserved.
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.\"
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.\" Author: Hartmut Brandt <harti@freebsd.org>
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $Begemot: libunimsg/man/unifunc.3,v 1.5 2005/05/23 12:04:55 brandt_h Exp $
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.\"
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.Dd May 23, 2005
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.Dt UNIFUNC 3
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.Os
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.Sh NAME
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.Nm libngatm ,
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.Nm uni_decode ,
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.Nm uni_decode_head ,
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.Nm uni_decode_body ,
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.Nm uni_decode_ie_hdr ,
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.Nm uni_decode_ie_body ,
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.Nm uni_encode ,
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.Nm uni_encode_msg_hdr ,
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.Nm uni_encode_ie ,
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.Nm uni_encode_ie_hdr ,
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.Nm uni_check_ie ,
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.Nm uni_print_cref ,
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.Nm uni_print_msghdr ,
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.Nm uni_print ,
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.Nm uni_print_ie ,
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.Nm uni_initcx ,
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.Nm uni_print_cx
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.Nd "ATM signalling library - message handling functions"
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.Sh LIBRARY
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Begemot ATM signalling library
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.Pq libngatm, -lngatm
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.Sh SYNOPSIS
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.In netnatm/msg/unistruct.h
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.In netnatm/msg/unimsglib.h
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.Ft int
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.Fn uni_decode "struct uni_msg *buf" "struct uni_all *msg" "struct unicx *cx"
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.Ft int
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.Fn uni_decode_head "struct uni_msg *buf" "struct uni_all *msg" "struct unicx *cx"
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.Ft int
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.Fn uni_decode_body "struct uni_msg *buf" "struct uni_all *msg" "struct unicx *cx"
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.Ft int
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.Fn uni_decode_ie_hdr "enum uni_ietype *type" "struct uni_iehdr *hdr" "struct uni_msg *buf" "struct unicx *cx" "u_int *ielen"
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.Ft int
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.Fn uni_decode_ie_body "enum uni_ietype type" "union uni_ieall *ie" "struct uni_msg *buf" "u_int ielen" "struct unicx *cx"
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.Ft int
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.Fn uni_encode "struct uni_msg *buf" "struct uni_all *msg" "struct unicx *cx"
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.Ft int
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.Fn uni_encode_msg_hdr "struct uni_msg *buf" "struct uni_msghdr *hdr" "enum uni_msgtype type" "struct unicx *cx" "int *mlen"
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.Ft int
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.Fn uni_encode_ie "enum uni_ietype type" "struct uni_msg *buf" "union uni_ieall *ie" "struct unicx *cx"
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.Ft int
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.Fn uni_encode_ie_hdr "struct uni_msg *buf" "enum uni_ietype type" "struct uni_iehdr *hdr" "u_int len" "struct unicx *cx"
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.Ft int
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.Fn uni_check_ie "enum uni_ietype type" "union uni_ieall *ie" "struct unicx *cx"
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.Ft void
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.Fn uni_print_cref "char *buf" "size_t buflen" "struct uni_cref *cref" "struct unicx *cx"
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.Ft void
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.Fn uni_print_msghdr "char *buf" "size_t buflen" "struct uni_msghdr *hdr" "struct unicx *cx"
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.Ft void
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.Fn uni_print "char *buf" "size_t buflen" "struct uni_all *msg" "struct unicx *cx"
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.Ft void
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.Fn uni_print_ie "char *buf" "size_t buflen" "enum uni_ietype type" "union uni_ieall *ie" "struct unicx *cx"
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.Ft void
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.Fn uni_initcx "struct unicx *cx"
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.Ft void
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.Fn uni_print_cx "char *buf" "size_t buflen" "struct unicx *cx"
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.Sh DESCRIPTION
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The
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.Nm
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library handles UNI 4.0 messages.
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For each information element and message
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type the header files contain a structure definition.
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Additionally there
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are a number of help structures and a global context structure for some
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of the library functions.
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This document describes the functions that are
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used to handle messages.
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.Ss DECODING
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Decoding is the process of taking an octet stream containing a UNI message
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or IE, parsing it and filling in a message or IE structure.
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.Pp
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The function
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.Fn uni_decode
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takes a message buffer, interprets it as a UNI message and fills in the
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structure pointed to by
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.Fa msg .
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It also takes a context argument and may fill the error array in the context.
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It returns -1 if there is an error decoding the message header and
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-2 if there is an error decoding the message body.
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The function returns 0 on success.
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.Pp
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The process of decoding a message can be split up by calling
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.Fn uni_decode_head
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and
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.Fn uni_decode_body .
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The first of these functions decodes only the message header and the second
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one decodes only the information elements.
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.Fn uni_decode_head
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returns 0 if it could decode the message header
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and -1 if the message could not be decoded (bad protocol
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identifier, bad length or broken call reference).
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.Fn uni_decode_body
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return 0 on success and -1 for unknown message types or if any
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IE had an error.
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.Pp
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The function
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.Fn uni_decode_ie_hdr
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decodes the next information element header.
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It returns the IE type and its length
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in the variables pointed to by
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.Va type
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and
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.Va ielen
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and stores the decoded header in the structure pointed to by
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.Va hdr .
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The function returns 0 on success and -1 if there were not enough bytes
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in the buffer left for a complete IE header.
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.Pp
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The function
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.Fn uni_decode_ie_body
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decodes the body of an information element. It is passed the buffer with the
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message
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.Fa buf ,
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the information element type
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.Fa type
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and length
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.Fa ielen .
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The IE is stored in the union pointed to by
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.Fa ie .
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The function returns -1 on errors and 0 on success.
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In any case the most correct
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number of bytes is consumed from the input buffer.
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.Ss ENCODING
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Encoding is the process of taking a message or IE structure and producing
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an octet stream from it.
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.Pp
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The function
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.Fn uni_encode
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encodes a UNI message.
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It returns -1 if the message type is out of bounds, -3
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if the message type is unknown.
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The encoding functions for the message types
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can return their own error codes.
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The function returns 0 on success.
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.Pp
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The function
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.Fn uni_encode_msg_hdr
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encodes a message header.
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The variable pointed to by
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.Fa mlen
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is set to the offset of the message length field from the begin of the
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byte stream.
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This is needed because the length of the message body will
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be known only after all the IEs have been encoded.
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Then the length
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has to be inserted into this place.
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The function returns -1 if the call reference
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was bad and 0 on success.
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.Pp
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The function
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.Fn uni_encode_ie
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encodes one information element.
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The function returns 0 on success or -1
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on errors.
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The function
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.Fn uni_encode_ie_hdr
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encodes the four byte IE header.
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The argument
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.Fa len
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is the maximum expected length of the information element, not the real length.
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The function inserts a 0 in the real length field.
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This must be
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fixed up by the caller after encoding the IE contents.
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The function
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return -1 if an empty IE is to be encoded (in this case the length field will
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have been set to 4) or 0 otherwise.
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.Ss CHECKING
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There exists a number of function that do consistency checks on information
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elements.
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Note, that these functions do not check inter-IE consistency, but
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each IE by itself.
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.Pp
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The function
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.Fn uni_check_ie
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check an information element for consistency.
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It returns 0 if the IE seems
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ok, -1 otherwise.
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.Ss PRINTING
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A number of functions can be used to print decoded messages and IEs in
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a human readable form.
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This is intended mainly for debugging.
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Some fields of the library context are used to control how the printing is done
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(see
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.Xr unistruct 3 ).
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Each of the function takes a
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.Fa buf
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and a
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.Fa buflen
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argument.
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The string that is generated in the buffer pointed to by
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.Fa buf
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is guaranteed to be NUL terminated.
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.Pp
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The function
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.Fn uni_print_cref
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formats a call reference taking into account special call references.
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The function
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.Fn uni_print_msg_hdr
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formats a message header.
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The functions
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.Fn uni_print
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and
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.Fn uni_print_ie
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print messages and information elements.
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.Ss CONTEXTS
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There are two functions for context handling.
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.Fn uni_initcx
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initializes a context with default values and
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.Fn uni_print_cx
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prints a context to the given buffer.
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.Sh SEE ALSO
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.Xr libngatm 3
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.Sh STANDARDS
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This implementation conforms to the applicable ITU-T
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recommendations and ATM Forum standards with the exception of some limitations
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(see the Configuration section).
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.Sh AUTHORS
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.An Hartmut Brandt Aq harti@freebsd.org
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