mirror of https://gerrit.osmocom.org/asn1c
4264 lines
73 KiB
Plaintext
4264 lines
73 KiB
Plaintext
#LyX 1.3 created this file. For more info see http://www.lyx.org/
|
|
\lyxformat 221
|
|
\textclass book
|
|
\begin_preamble
|
|
\usepackage{extramarks}
|
|
\lhead{\firstxmark}
|
|
\rfoot{\lastxmark}
|
|
\usepackage{color}
|
|
\definecolor{gray40}{gray}{.4}
|
|
\definecolor{urlblue}{rgb}{0,0,.6}
|
|
\usepackage[colorlinks=true,
|
|
linkcolor={gray40},
|
|
urlcolor={urlblue},
|
|
pdfauthor={Lev Walkin},
|
|
pdftitle={Using the Open Source ASN.1 Compiler},
|
|
pdfkeywords={ASN.1,asn1c,compiler}
|
|
]{hyperref}
|
|
%\fancyhf{}
|
|
%\fancyhead[LE,RO]{\thepage}
|
|
%\fancyhead[LO]{\rightmark}
|
|
%\fancyhead[RE]{\leftmark}
|
|
%\fancyfoot[R]{\lastxmark}
|
|
\end_preamble
|
|
\language english
|
|
\inputencoding latin1
|
|
\fontscheme times
|
|
\graphics default
|
|
\paperfontsize default
|
|
\spacing single
|
|
\papersize Default
|
|
\paperpackage a4
|
|
\use_geometry 0
|
|
\use_amsmath 0
|
|
\use_natbib 0
|
|
\use_numerical_citations 0
|
|
\paperorientation portrait
|
|
\secnumdepth 2
|
|
\tocdepth 2
|
|
\paragraph_separation indent
|
|
\defskip medskip
|
|
\quotes_language swedish
|
|
\quotes_times 2
|
|
\papercolumns 1
|
|
\papersides 2
|
|
\paperpagestyle fancy
|
|
|
|
\layout Title
|
|
|
|
Using the Open Source ASN.1 Compiler
|
|
\layout Author
|
|
|
|
Lev Walkin <
|
|
\begin_inset ERT
|
|
status Collapsed
|
|
|
|
\layout Standard
|
|
|
|
\backslash
|
|
href{mailto:vlm@lionet.info?Subject=asn1c}{vlm@lionet.info}
|
|
\end_inset
|
|
|
|
>
|
|
\layout Standard
|
|
|
|
|
|
\begin_inset ERT
|
|
status Open
|
|
|
|
\layout Standard
|
|
|
|
\backslash
|
|
lhead{This document describes
|
|
\backslash
|
|
href{http://lionet.info/asn1c}{asn1c-0.9.20}}
|
|
\layout Standard
|
|
|
|
\backslash
|
|
rhead{$Revision$}
|
|
\end_inset
|
|
|
|
|
|
\layout Standard
|
|
|
|
|
|
\begin_inset LatexCommand \tableofcontents{}
|
|
|
|
\end_inset
|
|
|
|
|
|
\layout Standard
|
|
|
|
|
|
\begin_inset ERT
|
|
status Open
|
|
|
|
\layout Standard
|
|
|
|
\backslash
|
|
pagestyle{headings}
|
|
\end_inset
|
|
|
|
|
|
\layout Part
|
|
|
|
Using the ASN.1 Compiler
|
|
\layout Chapter
|
|
|
|
Introduction to the ASN.1 Compiler
|
|
\layout Standard
|
|
|
|
The purpose of the ASN.1 compiler, of which this document is part, is to
|
|
convert the specifications in ASN.1 notation into some other language.
|
|
At this moment, only C and C++ target languages are supported, the latter
|
|
is in upward compatibility mode.
|
|
\layout Standard
|
|
|
|
The compiler reads the specification and emits a series of target language
|
|
structures (C's structs, unions, enums) describing the corresponding ASN.1
|
|
types.
|
|
The compiler also creates the code which allows automatic serialization
|
|
and deserialization of these structures using several standardized encoding
|
|
rules (BER, DER, XER).
|
|
\layout Standard
|
|
|
|
For example, suppose the following ASN.1 module is given
|
|
\begin_inset Foot
|
|
collapsed true
|
|
|
|
\layout Standard
|
|
|
|
Please look into Part
|
|
\begin_inset LatexCommand \vref{par:ASN.1-Basics}
|
|
|
|
\end_inset
|
|
|
|
for a quick reference on how to understand the ASN.1 notation.
|
|
\end_inset
|
|
|
|
:
|
|
\layout LyX-Code
|
|
|
|
RectangleTest DEFINITIONS ::=
|
|
\layout LyX-Code
|
|
|
|
BEGIN
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
Rectangle ::= SEQUENCE {
|
|
\layout LyX-Code
|
|
|
|
height INTEGER, -- Height of the rectangle
|
|
\layout LyX-Code
|
|
|
|
width INTEGER -- Width of the rectangle
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
END
|
|
\layout Standard
|
|
|
|
The compiler would read this ASN.1 definition and produce the following C
|
|
type
|
|
\begin_inset Foot
|
|
collapsed false
|
|
|
|
\layout Standard
|
|
|
|
|
|
\emph on
|
|
-fnative-types
|
|
\emph default
|
|
compiler option is used to produce basic C
|
|
\emph on
|
|
int
|
|
\emph default
|
|
types instead of infinite width INTEGER_t structures.
|
|
See Section
|
|
\begin_inset LatexCommand \vref{sec:Command-line-options}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\end_inset
|
|
|
|
:
|
|
\layout LyX-Code
|
|
|
|
typedef struct Rectangle_s {
|
|
\layout LyX-Code
|
|
|
|
int height;
|
|
\layout LyX-Code
|
|
|
|
int width;
|
|
\layout LyX-Code
|
|
|
|
} Rectangle_t;
|
|
\layout Standard
|
|
|
|
It would also create the code for converting this structure into platform-indepe
|
|
ndent wire representation (a serializer API) and the decoder of such wire
|
|
representation back into local, machine-specific type (a deserializer API).
|
|
\layout Section
|
|
|
|
Quick start with asn1c
|
|
\layout Standard
|
|
|
|
After building and installing the compiler, the
|
|
\emph on
|
|
asn1c
|
|
\begin_inset Foot
|
|
collapsed false
|
|
|
|
\layout Standard
|
|
|
|
The 1 symbol in asn
|
|
\series bold
|
|
1
|
|
\series default
|
|
c is a digit, not an
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
ell
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
letter.
|
|
\end_inset
|
|
|
|
|
|
\emph default
|
|
command may be used to compile the ASN.1 module
|
|
\begin_inset Foot
|
|
collapsed false
|
|
|
|
\layout Standard
|
|
|
|
This is probably
|
|
\series bold
|
|
not
|
|
\series default
|
|
what you want to try out right now -- read through the rest of this chapter
|
|
and check the Section
|
|
\begin_inset LatexCommand \vref{sec:Command-line-options}
|
|
|
|
\end_inset
|
|
|
|
to find out about
|
|
\series bold
|
|
-P
|
|
\series default
|
|
and
|
|
\series bold
|
|
-R
|
|
\series default
|
|
options.
|
|
\end_inset
|
|
|
|
:
|
|
\layout LyX-Code
|
|
|
|
asn1c
|
|
\emph on
|
|
<module.asn1>
|
|
\layout Standard
|
|
|
|
If several ASN.1 modules contain interdependencies, all of the files must
|
|
be specified altogether:
|
|
\layout LyX-Code
|
|
|
|
asn1c
|
|
\emph on
|
|
<module1.asn1> <module2.asn1> ...
|
|
\layout Standard
|
|
|
|
The compiler
|
|
\series bold
|
|
-E
|
|
\series default
|
|
and
|
|
\series bold
|
|
-EF
|
|
\series default
|
|
options are used for testing the parser and the semantic fixer, respectively.
|
|
These options will instruct the compiler to dump out the parsed (and fixed,
|
|
if
|
|
\series bold
|
|
-F
|
|
\series default
|
|
is involved) ASN.1 specification as it was "understood" by the compiler.
|
|
It might be useful to check whether a particular syntactic construction
|
|
is properly supported by the compiler.
|
|
\layout LyX-Code
|
|
|
|
asn1c
|
|
\series bold
|
|
-EF
|
|
\series default
|
|
|
|
\emph on
|
|
<module-to-test.asn1>
|
|
\layout Standard
|
|
|
|
The
|
|
\series bold
|
|
-P
|
|
\series default
|
|
option is used to dump the compiled output on the screen instead of creating
|
|
a bunch of .c and .h files on disk in the current directory.
|
|
You would probably want to start with
|
|
\series bold
|
|
-P
|
|
\series default
|
|
option instead of creating a mess in your current directory.
|
|
Another option,
|
|
\series bold
|
|
-R
|
|
\series default
|
|
, asks compiler to only generate the files which need to be generated, and
|
|
supress linking in the numerous support files.
|
|
\layout Standard
|
|
|
|
Print the compiled output instead of creating multiple source files:
|
|
\layout LyX-Code
|
|
|
|
asn1c
|
|
\series bold
|
|
-P
|
|
\series default
|
|
|
|
\emph on
|
|
<module-to-compile-and-print.asn1>
|
|
\layout Section
|
|
|
|
Recognizing compiler output
|
|
\layout Standard
|
|
|
|
After compiling, the following entities will be created in your current
|
|
directory:
|
|
\layout Itemize
|
|
|
|
A set of .c and .h files, generally a single pair for each type defined in
|
|
the ASN.1 specifications.
|
|
These files will be named similarly to the ASN.1 types (
|
|
\emph on
|
|
Rectangle.c
|
|
\emph default
|
|
and
|
|
\emph on
|
|
Rectangle.h
|
|
\emph default
|
|
for the RectangleTest ASN.1 module defined in the beginning of this document).
|
|
\layout Itemize
|
|
|
|
A set of helper .c and .h files which contain generic encoders, decoders and
|
|
other useful routines.
|
|
There will be quite a few of them, some of them even are not always necessary,
|
|
but the overall amount of code after compilation will be rather small anyway.
|
|
\layout Itemize
|
|
|
|
A
|
|
\emph on
|
|
Makefile.am.sample
|
|
\emph default
|
|
file mentioning all the files created at the earlier steps.
|
|
This file is suitable for either automake suite or the plain `make` utility.
|
|
\layout Standard
|
|
|
|
It is your responsibility to create .c file with the
|
|
\emph on
|
|
int main()
|
|
\emph default
|
|
routine.
|
|
\layout Standard
|
|
|
|
In other words, after compiling the Rectangle module, you have the following
|
|
set of files: { Makefile.am.sample, Rectangle.c, Rectangle.h,
|
|
\series bold
|
|
\SpecialChar \ldots{}
|
|
|
|
\series default
|
|
}, where
|
|
\series bold
|
|
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
\SpecialChar \ldots{}
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
|
|
\series default
|
|
stands for the set of additional
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
helper
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
files created by the compiler.
|
|
If you add a simple file with the
|
|
\emph on
|
|
int main()
|
|
\emph default
|
|
routine, it would even be possible to compile everything with the single
|
|
instruction:
|
|
\layout LyX-Code
|
|
|
|
cc -I.
|
|
-o rectangle.exe *.c # It could be
|
|
\emph on
|
|
that
|
|
\emph default
|
|
simple
|
|
\layout Standard
|
|
|
|
Refer to the Chapter
|
|
\begin_inset LatexCommand \vref{cha:Step-by-step-examples}
|
|
|
|
\end_inset
|
|
|
|
for a sample
|
|
\emph on
|
|
int main()
|
|
\emph default
|
|
routine.
|
|
\layout Section
|
|
|
|
|
|
\begin_inset LatexCommand \label{sec:Command-line-options}
|
|
|
|
\end_inset
|
|
|
|
Command line options
|
|
\layout Standard
|
|
|
|
The following table summarizes the asn1c command line options.
|
|
\layout Standard
|
|
|
|
|
|
\begin_inset Tabular
|
|
<lyxtabular version="3" rows="26" columns="2">
|
|
<features islongtable="true">
|
|
<column alignment="left" valignment="top" leftline="true" width="0">
|
|
<column alignment="block" valignment="top" leftline="true" rightline="true" width="3in">
|
|
<row topline="true" bottomline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\series bold
|
|
\size small
|
|
Overall Options
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\series bold
|
|
\size small
|
|
Description
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-E
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Stop after the parsing stage and print the reconstructed ASN.1 specification
|
|
code to the standard output.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-F
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Used together with -E, instructs the compiler to stop after the ASN.1 syntax
|
|
tree fixing stage and dump the reconstructed ASN.1 specification to the
|
|
standard output.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-P
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Dump the compiled output to the standard output instead of cre- ating the
|
|
target language files on disk.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-R
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Restrict the compiler to generate only the ASN.1 tables, omit- ting the usual
|
|
support code.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-S
|
|
\emph on
|
|
<directory>
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Use the specified directory with ASN.1 skeleton files.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true" bottomline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-X
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Generate the XML DTD for the specified ASN.1 modules.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\series bold
|
|
\size small
|
|
Warning Options
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\series bold
|
|
\size small
|
|
Description
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-Werror
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Treat warnings as errors; abort if any warning is produced.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-Wdebug-lexer
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Enable lexer debugging during the ASN.1 parsing stage.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-Wdebug-fixer
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Enable ASN.1 syntax tree fixer debugging during the fixing stage.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true" bottomline="true" newpage="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-Wdebug-compiler
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Enable debugging during the actual compile time.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\series bold
|
|
\size small
|
|
Language Options
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\series bold
|
|
\size small
|
|
Description
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-fall-defs-global
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Normally the compiler hides the definitions (asn_DEF_xxx) of the inner structure
|
|
elements (members of SEQUENCE, SET and other types).
|
|
This option makes all such definitions global.
|
|
Enabling this option may pollute the namespace by making lots of asn_DEF_xxx
|
|
structures globally visible, but will allow you to manipulate (encode and
|
|
decode) the individual members of any complex ASN.1 structure.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-fbless-SIZE
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Allow SIZE() constraint for INTEGER, ENUMERATED, and other types for which
|
|
this constraint is normally prohibited by the standard.
|
|
This is a violation of an ASN.1 standard and compiler may fail to produce
|
|
the meaningful code.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-fcompound-names
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Use complex names for C structures.
|
|
Using complex names prevents name clashes in case the module reuses the
|
|
same identifiers in multiple contexts.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-findirect-choice
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
When generating code for a CHOICE type, compile the CHOICE members as indirect
|
|
pointers instead of declaring them inline.
|
|
Consider using this option together with
|
|
\series bold
|
|
-fno-include-deps
|
|
\series default
|
|
to prevent circular references.
|
|
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-fknown-extern-type=
|
|
\emph on
|
|
<name>
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Pretend the specified type is known.
|
|
The compiler will assume the target language source files for the given
|
|
type have been provided manually.
|
|
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-fnative-types
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Use the native machine's data types (int, double) whenever possible, instead
|
|
of the compound INTEGER_t, ENUMERATED_t and REAL_t types.
|
|
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-fno-constraints
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Do not generate ASN.1 subtype constraint checking code.
|
|
This may produce a shorter executable.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-fno-include-deps
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Do not generate courtesy #include lines for non-critical dependencies.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-funnamed-unions
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Enable unnamed unions in the definitions of target language's structures.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true" bottomline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-fskeletons-copy
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Copy support files rather than symlink them.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\series bold
|
|
\size small
|
|
Output Options
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\series bold
|
|
\size small
|
|
Description
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-print-constraints
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
When -EF are also specified, this option forces the compiler to explain
|
|
its internal understanding of subtype constraints.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
<row topline="true" bottomline="true">
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
-print-lines
|
|
\end_inset
|
|
</cell>
|
|
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
|
|
\begin_inset Text
|
|
|
|
\layout Standard
|
|
|
|
|
|
\size small
|
|
Generate "-- #line" comments in -E output.
|
|
\end_inset
|
|
</cell>
|
|
</row>
|
|
</lyxtabular>
|
|
|
|
\end_inset
|
|
|
|
|
|
\layout Chapter
|
|
|
|
Using the ASN.1 Compiler
|
|
\layout Section
|
|
|
|
Invoking the ASN.1 helper code
|
|
\begin_inset OptArg
|
|
collapsed true
|
|
|
|
\layout Standard
|
|
|
|
Invoking the helper code
|
|
\end_inset
|
|
|
|
|
|
\layout Standard
|
|
|
|
First of all, you should include one or more header files into your application.
|
|
Typically, it is enough to include the header file of the main PDU type.
|
|
For our Rectangle module, including the Rectangle.h file is sufficient:
|
|
\layout LyX-Code
|
|
|
|
#include <Rectangle.h>
|
|
\layout Standard
|
|
|
|
The header files defines the C structure corresponding to the ASN.1 definition
|
|
of a rectangle and the declaration of the ASN.1 type descriptor, which is
|
|
used as an argument to most of the functions provided by the ASN.1 module.
|
|
For example, here is the code which frees the Rectangle_t structure:
|
|
\layout LyX-Code
|
|
|
|
Rectangle_t *rect = ...;
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
asn_DEF_Rectangle.free_struct(&asn_DEF_Rectangle,
|
|
\layout LyX-Code
|
|
|
|
rect, 0);
|
|
\layout Standard
|
|
|
|
This code defines a
|
|
\emph on
|
|
rect
|
|
\emph default
|
|
pointer which points to the Rectangle_t structure which needs to be freed.
|
|
The second line invokes the generic
|
|
\emph on
|
|
free_struct()
|
|
\emph default
|
|
routine created specifically for this Rectangle_t structure.
|
|
The
|
|
\emph on
|
|
asn_DEF_Rectangle
|
|
\emph default
|
|
is the type descriptor, which holds a collection of routines to deal with
|
|
the Rectangle_t structure.
|
|
\layout Standard
|
|
|
|
The following member functions of the asn_DEF_Rectangle type descriptor
|
|
are of interest:
|
|
\layout Description
|
|
|
|
ber_decoder This is the generic
|
|
\emph on
|
|
restartable
|
|
\begin_inset Foot
|
|
collapsed false
|
|
|
|
\layout Standard
|
|
|
|
Restartable means that if the decoder encounters the end of the buffer,
|
|
it will fail, but may later be invoked again with the rest of the buffer
|
|
to continue decoding.
|
|
\end_inset
|
|
|
|
|
|
\emph default
|
|
BER decoder (Basic Encoding Rules).
|
|
This decoder would create and/or fill the target structure for you.
|
|
Please refer to Section
|
|
\begin_inset LatexCommand \vref{sub:Decoding-BER}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\layout Description
|
|
|
|
der_encoder This is the generic DER encoder (Distinguished Encoding Rules).
|
|
This encoder will take the target structure and encode it into a series
|
|
of bytes.
|
|
Please refer to Section
|
|
\begin_inset LatexCommand \vref{sub:Encoding-DER}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\layout Description
|
|
|
|
xer_encoder This is the XER encoder (XML Encoding Rules).
|
|
This encoder will take the target structure and represent it as an XML
|
|
(text) document using either BASIC-XER or CANONICAL-XER encoding rules.
|
|
Please refer to Section
|
|
\begin_inset LatexCommand \vref{sub:Encoding-XER}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\layout Description
|
|
|
|
xer_decoder This is the generic XER decoder.
|
|
It takes both BASIC-XER or CANONICAL-XER encodings and deserializes the
|
|
data into a local, machine-dependent representation.
|
|
Please refer to Section
|
|
\begin_inset LatexCommand \vref{sub:Decoding-XER}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\layout Description
|
|
|
|
check_constraints Check that the contents of the target structure are semantical
|
|
ly valid and constrained to appropriate implicit or explicit subtype constraints.
|
|
Please refer to Section
|
|
\begin_inset LatexCommand \vref{sub:Validating-the-target}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\layout Description
|
|
|
|
print_struct This function convert the contents of the passed target structure
|
|
into human readable form.
|
|
This form is not formal and cannot be converted back into the structure,
|
|
but it may turn out to be useful for debugging or quick-n-dirty printing.
|
|
Please refer to Section
|
|
\begin_inset LatexCommand \vref{sub:Printing-the-target}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\layout Description
|
|
|
|
free_struct This is a generic disposal which frees the target structure.
|
|
Please refer to Section
|
|
\begin_inset LatexCommand \vref{sub:Freeing-the-target}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\layout Standard
|
|
|
|
Each of the above function takes the type descriptor (
|
|
\emph on
|
|
asn_DEF_\SpecialChar \ldots{}
|
|
|
|
\emph default
|
|
) and the target structure (
|
|
\emph on
|
|
rect
|
|
\emph default
|
|
, in the above example).
|
|
\layout Subsection
|
|
|
|
|
|
\begin_inset LatexCommand \label{sub:Decoding-BER}
|
|
|
|
\end_inset
|
|
|
|
Decoding BER
|
|
\layout Standard
|
|
|
|
The Basic Encoding Rules describe the most widely used (by the ASN.1 community)
|
|
way to encode and decode a given structure in a machine-independent way.
|
|
Several other encoding rules (CER, DER) define a more restrictive versions
|
|
of BER, so the generic BER parser is also capable of decoding the data
|
|
encoded by CER and DER encoders.
|
|
The opposite is not true.
|
|
\layout Standard
|
|
|
|
|
|
\emph on
|
|
The ASN.1 compiler provides the generic BER decoder which is implicitly capable
|
|
of decoding BER, CER and DER encoded data.
|
|
\layout Standard
|
|
|
|
The decoder is restartable (stream-oriented), which means that in case the
|
|
buffer has less data than it is expected, the decoder will process whatever
|
|
there is available and ask for more data to be provided.
|
|
Please note that the decoder may actually process less data than it was
|
|
given in the buffer, which means that you must be able to make the next
|
|
buffer contain the unprocessed part of the previous buffer.
|
|
\layout Standard
|
|
|
|
Suppose, you have two buffers of encoded data: 100 bytes and 200 bytes.
|
|
\layout Itemize
|
|
|
|
You may concatenate these buffers and feed the BER decoder with 300 bytes
|
|
of data, or
|
|
\layout Itemize
|
|
|
|
You may feed it the first buffer of 100 bytes of data, realize that the
|
|
ber_decoder consumed only 95 bytes from it and later feed the decoder with
|
|
205 bytes buffer which consists of 5 unprocessed bytes from the first buffer
|
|
and the additional 200 bytes from the second buffer.
|
|
\layout Standard
|
|
|
|
This is not as convenient as it could be (like, the BER encoder could consume
|
|
the whole 100 bytes and keep these 5 bytes in some temporary storage),
|
|
but in case of existing stream based processing it might actually fit well
|
|
into existing algorithm.
|
|
Suggestions are welcome.
|
|
\layout Standard
|
|
|
|
Here is the simplest example of BER decoding.
|
|
\layout LyX-Code
|
|
|
|
Rectangle_t *
|
|
\layout LyX-Code
|
|
|
|
simple_deserializer(const void *buffer, size_t buf_size) {
|
|
\layout LyX-Code
|
|
|
|
Rectangle_t *rect = 0; /* Note this 0! */
|
|
\layout LyX-Code
|
|
|
|
asn_dec_rval_t rval;
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
rval =
|
|
\series bold
|
|
asn_DEF_Rectangle.ber_decoder
|
|
\series default
|
|
(0,
|
|
\layout LyX-Code
|
|
|
|
&asn_DEF_Rectangle,
|
|
\layout LyX-Code
|
|
|
|
(void **)&rect,
|
|
\layout LyX-Code
|
|
|
|
buffer, buf_size,
|
|
\layout LyX-Code
|
|
|
|
0);
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
if(rval
|
|
\series bold
|
|
.code
|
|
\series default
|
|
== RC_OK) {
|
|
\layout LyX-Code
|
|
|
|
return rect; /* Decoding succeeded */
|
|
\layout LyX-Code
|
|
|
|
} else {
|
|
\layout LyX-Code
|
|
|
|
/* Free partially decoded rect */
|
|
\layout LyX-Code
|
|
|
|
asn_DEF_Rectangle.free_struct(
|
|
\layout LyX-Code
|
|
|
|
&asn_DEF_Rectangle, rect, 0);
|
|
\layout LyX-Code
|
|
|
|
return 0;
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout Standard
|
|
|
|
The code above defines a function,
|
|
\emph on
|
|
simple_deserializer
|
|
\emph default
|
|
, which takes a buffer and its length and is expected to return a pointer
|
|
to the Rectangle_t structure.
|
|
Inside, it tries to convert the bytes passed into the target structure
|
|
(rect) using the BER decoder and returns the rect pointer afterwards.
|
|
If the structure cannot be deserialized, it frees the memory which might
|
|
be left allocated by the unfinished
|
|
\emph on
|
|
ber_decoder
|
|
\emph default
|
|
routine and returns 0 (no data).
|
|
(This
|
|
\series bold
|
|
freeing is necessary
|
|
\series default
|
|
because the ber_decoder is a restartable procedure, and may fail just because
|
|
there is more data needs to be provided before decoding could be finalized).
|
|
The code above obviously does not take into account the way the
|
|
\emph on
|
|
ber_decoder()
|
|
\emph default
|
|
failed, so the freeing is necessary because the part of the buffer may
|
|
already be decoded into the structure by the time something goes wrong.
|
|
\layout Standard
|
|
|
|
A little less wordy would be to invoke a globally available
|
|
\emph on
|
|
ber_decode()
|
|
\emph default
|
|
function instead of dereferencing the asn_DEF_Rectangle type descriptor:
|
|
\layout LyX-Code
|
|
|
|
rval = ber_decode(0, &asn_DEF_Rectangle, (void **)&rect,
|
|
\layout LyX-Code
|
|
|
|
buffer, buf_size);
|
|
\layout Standard
|
|
|
|
Note that the initial (asn_DEF_Rectangle.ber_decoder) reference is gone,
|
|
and also the last argument (0) is no longer necessary.
|
|
\layout Standard
|
|
|
|
These two ways of BER decoder invocations are fully equivalent.
|
|
\layout Standard
|
|
|
|
The BER de
|
|
\emph on
|
|
coder
|
|
\emph default
|
|
may fail because of (
|
|
\emph on
|
|
the following RC_\SpecialChar \ldots{}
|
|
codes are defined in ber_decoder.h
|
|
\emph default
|
|
):
|
|
\layout Itemize
|
|
|
|
RC_WMORE: There is more data expected than it is provided (stream mode continuat
|
|
ion feature);
|
|
\layout Itemize
|
|
|
|
RC_FAIL: General failure to decode the buffer;
|
|
\layout Itemize
|
|
|
|
\SpecialChar \ldots{}
|
|
other codes may be defined as well.
|
|
\layout Standard
|
|
|
|
Together with the return code (.code) the asn_dec_rval_t type contains the
|
|
number of bytes which is consumed from the buffer.
|
|
In the previous hypothetical example of two buffers (of 100 and 200 bytes),
|
|
the first call to ber_decode() would return with .code = RC_WMORE and .consumed
|
|
= 95.
|
|
The .consumed field of the BER decoder return value is
|
|
\series bold
|
|
always
|
|
\series default
|
|
valid, even if the decoder succeeds or fails with any other return code.
|
|
\layout Standard
|
|
|
|
Please look into ber_decoder.h for the precise definition of ber_decode()
|
|
and related types.
|
|
\layout Subsection
|
|
|
|
|
|
\begin_inset LatexCommand \label{sub:Encoding-DER}
|
|
|
|
\end_inset
|
|
|
|
Encoding DER
|
|
\layout Standard
|
|
|
|
The Distinguished Encoding Rules is the
|
|
\emph on
|
|
canonical
|
|
\emph default
|
|
variant of BER encoding rules.
|
|
The DER is best suited to encode the structures where all the lengths are
|
|
known beforehand.
|
|
This is probably exactly how you want to encode: either after a BER decoding
|
|
or after a manual fill-up, the target structure contains the data which
|
|
size is implicitly known before encoding.
|
|
Among other uses, the DER encoding is used to encode X.509 certificates.
|
|
\layout Standard
|
|
|
|
As with BER decoder, the DER encoder may be invoked either directly from
|
|
the ASN.1 type descriptor (asn_DEF_Rectangle) or from the stand-alone function,
|
|
which is somewhat simpler:
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
/*
|
|
\layout LyX-Code
|
|
|
|
* This is the serializer itself,
|
|
\layout LyX-Code
|
|
|
|
* it supplies the DER encoder with the
|
|
\layout LyX-Code
|
|
|
|
* pointer to the custom output function.
|
|
\layout LyX-Code
|
|
|
|
*/
|
|
\layout LyX-Code
|
|
|
|
ssize_t
|
|
\layout LyX-Code
|
|
|
|
simple_serializer(FILE *ostream, Rectangle_t *rect) {
|
|
\layout LyX-Code
|
|
|
|
asn_enc_rval_t er; /* Encoder return value */
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
er = der_encode(&asn_DEF_Rect, rect,
|
|
\layout LyX-Code
|
|
|
|
write_stream, ostream);
|
|
\layout LyX-Code
|
|
|
|
if(er.
|
|
\series bold
|
|
encoded
|
|
\series default
|
|
== -1) {
|
|
\layout LyX-Code
|
|
|
|
/*
|
|
\layout LyX-Code
|
|
|
|
* Failed to encode the rectangle data.
|
|
\layout LyX-Code
|
|
|
|
*/
|
|
\layout LyX-Code
|
|
|
|
fprintf(stderr,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Cannot encode %s: %s
|
|
\backslash
|
|
n
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\layout LyX-Code
|
|
|
|
er.
|
|
\series bold
|
|
failed_type
|
|
\series default
|
|
->name,
|
|
\layout LyX-Code
|
|
|
|
strerror(errno));
|
|
\layout LyX-Code
|
|
|
|
return -1;
|
|
\layout LyX-Code
|
|
|
|
} else {
|
|
\layout LyX-Code
|
|
|
|
/* Return the number of bytes */
|
|
\layout LyX-Code
|
|
|
|
return er.encoded;
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout Standard
|
|
|
|
As you see, the DER encoder does not write into some sort of buffer or something.
|
|
It just invokes the custom function (possible, multiple times) which would
|
|
save the data into appropriate storage.
|
|
The optional argument
|
|
\emph on
|
|
app_key
|
|
\emph default
|
|
is opaque for the DER encoder code and just used by
|
|
\emph on
|
|
_write_stream()
|
|
\emph default
|
|
as the pointer to the appropriate output stream to be used.
|
|
\layout Standard
|
|
|
|
If the custom write function is not given (passed as 0), then the DER encoder
|
|
will essentially do the same thing (i.e., encode the data) but no callbacks
|
|
will be invoked (so the data goes nowhere).
|
|
It may prove useful to determine the size of the structure's encoding before
|
|
actually doing the encoding
|
|
\begin_inset Foot
|
|
collapsed false
|
|
|
|
\layout Standard
|
|
|
|
It is actually faster too: the encoder might skip over some computations
|
|
which aren't important for the size determination.
|
|
\end_inset
|
|
|
|
.
|
|
\layout Standard
|
|
|
|
Please look into der_encoder.h for the precise definition of der_encode()
|
|
and related types.
|
|
\layout Subsection
|
|
|
|
|
|
\begin_inset LatexCommand \label{sub:Encoding-XER}
|
|
|
|
\end_inset
|
|
|
|
Encoding XER
|
|
\layout Standard
|
|
|
|
The XER stands for XML Encoding Rules, where XML, in turn, is eXtensible
|
|
Markup Language, a text-based format for information exchange.
|
|
The encoder routine API comes in two flavors: stdio-based and callback-based.
|
|
With the callback-based encoder, the encoding process is very similar to
|
|
the DER one, described in Section
|
|
\begin_inset LatexCommand \vref{sub:Encoding-DER}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
The following example uses the definition of write_stream() from up there.
|
|
\layout LyX-Code
|
|
|
|
/*
|
|
\layout LyX-Code
|
|
|
|
* This procedure generates the XML document
|
|
\layout LyX-Code
|
|
|
|
* by invoking the XER encoder.
|
|
\layout LyX-Code
|
|
|
|
* NOTE: Do not copy this code verbatim!
|
|
\layout LyX-Code
|
|
|
|
* If the stdio output is necessary,
|
|
\layout LyX-Code
|
|
|
|
* use the xer_fprint() procedure instead.
|
|
\layout LyX-Code
|
|
|
|
* See Section
|
|
\begin_inset LatexCommand \vref{sub:Printing-the-target}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\layout LyX-Code
|
|
|
|
*/
|
|
\layout LyX-Code
|
|
|
|
int
|
|
\layout LyX-Code
|
|
|
|
print_as_XML(FILE *ostream, Rectangle_t *rect) {
|
|
\layout LyX-Code
|
|
|
|
asn_enc_rval_t er; /* Encoder return value */
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
er = xer_encode(&asn_DEF_Rectangle, rect,
|
|
\layout LyX-Code
|
|
|
|
XER_F_BASIC, /* BASIC-XER or CANONICAL-XER */
|
|
\layout LyX-Code
|
|
|
|
write_stream, ostream);
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
return (er.encoded == -1) ? -1 : 0;
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout Standard
|
|
|
|
Please look into xer_encoder.h for the precise definition of xer_encode()
|
|
and related types.
|
|
\layout Standard
|
|
|
|
See Section
|
|
\begin_inset LatexCommand \ref{sub:Printing-the-target}
|
|
|
|
\end_inset
|
|
|
|
for the example of stdio-based XML encoder and other pretty-printing suggestion
|
|
s.
|
|
\layout Subsection
|
|
|
|
|
|
\begin_inset LatexCommand \label{sub:Decoding-XER}
|
|
|
|
\end_inset
|
|
|
|
Decoding XER
|
|
\layout Standard
|
|
|
|
The data encoded using the XER rules can be subsequently decoded using the
|
|
xer_decode() API call:
|
|
\layout LyX-Code
|
|
|
|
Rectangle_t *
|
|
\layout LyX-Code
|
|
|
|
XML_to_Rectangle(const void *buffer, size_t buf_size) {
|
|
\layout LyX-Code
|
|
|
|
Rectangle_t *rect = 0; /* Note this 0! */
|
|
\layout LyX-Code
|
|
|
|
asn_dec_rval_t rval;
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
rval = xer_decode(0, &asn_DEF_Rectangle, (void **)&rect,
|
|
\layout LyX-Code
|
|
|
|
buffer, buf_size);
|
|
\layout LyX-Code
|
|
|
|
if(rval
|
|
\series bold
|
|
.code
|
|
\series default
|
|
== RC_OK) {
|
|
\layout LyX-Code
|
|
|
|
return rect; /* Decoding succeeded */
|
|
\layout LyX-Code
|
|
|
|
} else {
|
|
\layout LyX-Code
|
|
|
|
/* Free partially decoded rect */
|
|
\layout LyX-Code
|
|
|
|
asn_DEF_Rectangle.free_struct(
|
|
\layout LyX-Code
|
|
|
|
&asn_DEF_Rectangle, rect, 0);
|
|
\layout LyX-Code
|
|
|
|
return 0;
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout Standard
|
|
|
|
The decoder takes both BASIC-XER and CANONICAL-XER encodings.
|
|
\layout Standard
|
|
|
|
The decoder shares its data consumption properties with BER decoder; please
|
|
read the Section
|
|
\begin_inset LatexCommand \vref{sub:Decoding-BER}
|
|
|
|
\end_inset
|
|
|
|
to know more.
|
|
\layout Standard
|
|
|
|
Please look into xer_decoder.h for the precise definition of xer_decode()
|
|
and related types.
|
|
\layout Subsection
|
|
|
|
|
|
\begin_inset LatexCommand \label{sub:Validating-the-target}
|
|
|
|
\end_inset
|
|
|
|
Validating the target structure
|
|
\layout Standard
|
|
|
|
Sometimes the target structure needs to be validated.
|
|
For example, if the structure was created by the application (as opposed
|
|
to being decoded from some external source), some important information
|
|
required by the ASN.1 specification might be missing.
|
|
On the other hand, the successful decoding of the data from some external
|
|
source does not necessarily mean that the data is fully valid either.
|
|
It might well be the case that the specification describes some subtype
|
|
constraints that were not taken into account during decoding, and it would
|
|
actually be useful to perform the last check when the data is ready to
|
|
be encoded or when the data has just been decoded to ensure its validity
|
|
according to some stricter rules.
|
|
\layout Standard
|
|
|
|
The asn_check_constraints() function checks the type for various implicit
|
|
and explicit constraints.
|
|
It is recommended to use asn_check_constraints() function after each decoding
|
|
and before each encoding.
|
|
\layout Standard
|
|
|
|
Please look into constraints.h for the precise definition of asn_check_constraint
|
|
s() and related types.
|
|
\layout Subsection
|
|
|
|
|
|
\begin_inset LatexCommand \label{sub:Printing-the-target}
|
|
|
|
\end_inset
|
|
|
|
Printing the target structure
|
|
\layout Standard
|
|
|
|
There are two ways to print the target structure: either invoke the print_struct
|
|
member of the ASN.1 type descriptor, or using the asn_fprint() function,
|
|
which is a simpler wrapper of the former:
|
|
\layout LyX-Code
|
|
|
|
asn_fprint(stdout, &asn_DEF_Rectangle, rect);
|
|
\layout Standard
|
|
|
|
Please look into constr_TYPE.h for the precise definition of asn_fprint()
|
|
and related types.
|
|
\layout Standard
|
|
|
|
Another practical alternative to this custom format printing would be to
|
|
invoke XER encoder.
|
|
The default BASIC-XER encoder performs reasonable formatting for the output
|
|
to be useful and human readable.
|
|
To invoke the XER decoder in a manner similar to asn_fprint(), use the
|
|
xer_fprint() call:
|
|
\layout LyX-Code
|
|
|
|
xer_fprint(stdout, &asn_DEF_Rectangle, rect);
|
|
\layout Standard
|
|
|
|
See Section
|
|
\begin_inset LatexCommand \vref{sub:Encoding-XER}
|
|
|
|
\end_inset
|
|
|
|
for XML-related details.
|
|
\layout Subsection
|
|
|
|
|
|
\begin_inset LatexCommand \label{sub:Freeing-the-target}
|
|
|
|
\end_inset
|
|
|
|
Freeing the target structure
|
|
\layout Standard
|
|
|
|
Freeing the structure is slightly more complex than it may seem to.
|
|
When the ASN.1 structure is freed, all the members of the structure and
|
|
their submembers etc etc are recursively freed too.
|
|
But it might not be feasible to free the structure itself.
|
|
Consider the following case:
|
|
\layout LyX-Code
|
|
|
|
struct my_figure { /* The custom structure */
|
|
\layout LyX-Code
|
|
|
|
int flags; /* <some custom member> */
|
|
\layout LyX-Code
|
|
|
|
/* The type is generated by the ASN.1 compiler */
|
|
\layout LyX-Code
|
|
|
|
|
|
\emph on
|
|
Rectangle_t rect;
|
|
\layout LyX-Code
|
|
|
|
/* other members of the structure */
|
|
\layout LyX-Code
|
|
|
|
};
|
|
\layout Standard
|
|
|
|
In this example, the application programmer defined a custom structure with
|
|
one ASN.1-derived member (rect).
|
|
This member is not a reference to the Rectangle_t, but an in-place inclusion
|
|
of the Rectangle_t structure.
|
|
If the freeing is necessary, the usual procedure of freeing everything
|
|
must not be applied to the &rect pointer itself, because it does not point
|
|
to the memory block directly allocated by the memory allocation routine,
|
|
but instead lies within a block allocated for the my_figure structure.
|
|
\layout Standard
|
|
|
|
To solve this problem, the free_struct routine has the additional argument
|
|
(besides the obvious type descriptor and target structure pointers), which
|
|
is the flag specifying whether the outer pointer itself must be freed (0,
|
|
default) or it should be left intact (non-zero value).
|
|
\layout LyX-Code
|
|
|
|
|
|
\series bold
|
|
/* 1.
|
|
Rectangle_t is defined within my_figure */
|
|
\layout LyX-Code
|
|
|
|
struct my_figure {
|
|
\layout LyX-Code
|
|
|
|
Rectangle_t rect;
|
|
\layout LyX-Code
|
|
|
|
} *mf =
|
|
\series bold
|
|
...
|
|
\series default
|
|
;
|
|
\layout LyX-Code
|
|
|
|
/*
|
|
\layout LyX-Code
|
|
|
|
* Freeing the Rectangle_t
|
|
\layout LyX-Code
|
|
|
|
* without freeing the mf->rect area
|
|
\layout LyX-Code
|
|
|
|
*/
|
|
\layout LyX-Code
|
|
|
|
asn_DEF_Rectangle.free_struct(
|
|
\layout LyX-Code
|
|
|
|
&asn_DEF_Rectangle, &mf->rect,
|
|
\series bold
|
|
1
|
|
\emph on
|
|
|
|
\emph default
|
|
/* !free */
|
|
\series default
|
|
);
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\series bold
|
|
/* 2.
|
|
Rectangle_t is a stand-alone pointer */
|
|
\layout LyX-Code
|
|
|
|
Rectangle_t *rect =
|
|
\series bold
|
|
...
|
|
\series default
|
|
;
|
|
\layout LyX-Code
|
|
|
|
/*
|
|
\layout LyX-Code
|
|
|
|
* Freeing the Rectangle_t
|
|
\layout LyX-Code
|
|
|
|
* and freeing the rect pointer
|
|
\layout LyX-Code
|
|
|
|
*/
|
|
\layout LyX-Code
|
|
|
|
asn_DEF_Rectangle.free_struct(
|
|
\layout LyX-Code
|
|
|
|
&asn_DEF_Rectangle, rect,
|
|
\series bold
|
|
0
|
|
\emph on
|
|
|
|
\emph default
|
|
/* free the pointer too */
|
|
\series default
|
|
);
|
|
\layout Standard
|
|
|
|
It is safe to invoke the
|
|
\emph on
|
|
free_struct
|
|
\emph default
|
|
function with the target structure pointer set to 0 (NULL), the function
|
|
will do nothing.
|
|
\layout Chapter
|
|
|
|
|
|
\begin_inset LatexCommand \label{cha:Step-by-step-examples}
|
|
|
|
\end_inset
|
|
|
|
Step by step examples
|
|
\layout Section
|
|
|
|
A
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Rectangle
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
Encoder
|
|
\layout Standard
|
|
|
|
This example will help you to create a simple BER and XER encoder of a
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Rectangle
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
type used throughout this document.
|
|
\layout Enumerate
|
|
|
|
Create a file named
|
|
\series bold
|
|
rectangle.asn1
|
|
\series default
|
|
with the following contents:
|
|
\begin_deeper
|
|
\layout LyX-Code
|
|
|
|
RectangleModule1 DEFINITIONS ::=
|
|
\layout LyX-Code
|
|
|
|
BEGIN
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
Rectangle ::= SEQUENCE {
|
|
\layout LyX-Code
|
|
|
|
height INTEGER,
|
|
\layout LyX-Code
|
|
|
|
width INTEGER
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
END
|
|
\end_deeper
|
|
\layout Enumerate
|
|
|
|
Compile it into the set of .c and .h files using asn1c compiler
|
|
\begin_inset LatexCommand \cite{ASN1C}
|
|
|
|
\end_inset
|
|
|
|
:
|
|
\begin_deeper
|
|
\layout LyX-Code
|
|
|
|
|
|
\emph on
|
|
asn1c -fnative-types
|
|
\series bold
|
|
\emph default
|
|
rectangle.asn1
|
|
\end_deeper
|
|
\layout Enumerate
|
|
|
|
Alternatively, use the Online ASN.1 compiler
|
|
\begin_inset LatexCommand \cite{AONL}
|
|
|
|
\end_inset
|
|
|
|
by uploading the
|
|
\series bold
|
|
rectangle.asn1
|
|
\series default
|
|
file into the Web form and unpacking the produced archive on your computer.
|
|
\layout Enumerate
|
|
|
|
By this time, you should have gotten multiple files in the current directory,
|
|
including the
|
|
\series bold
|
|
Rectangle.c
|
|
\series default
|
|
and
|
|
\series bold
|
|
Rectangle.h
|
|
\series default
|
|
.
|
|
\layout Enumerate
|
|
|
|
Create a main() routine which creates the Rectangle_t structure in memory
|
|
and encodes it using BER and XER encoding rules.
|
|
Let's name the file
|
|
\series bold
|
|
main.c
|
|
\series default
|
|
:
|
|
\begin_inset ERT
|
|
status Open
|
|
|
|
\layout Standard
|
|
|
|
\backslash
|
|
clearpage{}
|
|
\end_inset
|
|
|
|
|
|
\begin_deeper
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
#include <stdio.h>
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
#include <sys/types.h>
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
#include <Rectangle.h> /* Rectangle ASN.1 type */
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/*
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
* This is a custom function which writes the
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
* encoded output into some FILE stream.
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
*/
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
static int
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
write_out(const void *buffer, size_t size, void *app_key) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
FILE *out_fp = app_key;
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
size_t wrote;
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
wrote = fwrite(buffer, 1, size, out_fp);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
return (wrote == size) ? 0 : -1;
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
int main(int ac, char **av) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
Rectangle_t *rectangle; /* Type to encode */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
asn_enc_rval_t ec; /* Encoder return value */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* Allocate the Rectangle_t */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
rectangle = calloc(1, sizeof(Rectangle_t)); /* not malloc! */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
if(!rectangle) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
perror(
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
calloc() failed
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
exit(71); /* better, EX_OSERR */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* Initialize the Rectangle members */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
rectangle->height = 42; /* any random value */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
rectangle->width = 23; /* any random value */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* BER encode the data if filename is given */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
if(ac < 2) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
fprintf(stderr,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Specify filename for BER output
|
|
\backslash
|
|
n
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
} else {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
const char *filename = av[1];
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
FILE *fp = fopen(filename,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
wb
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
); /* for BER output */
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
if(!fp) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
perror(filename);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
exit(71); /* better, EX_OSERR */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* Encode the Rectangle type as BER (DER) */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
ec = der_encode(&asn_DEF_Rectangle,
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
rectangle, write_out, fp);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
fclose(fp);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
if(ec.encoded == -1) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
fprintf(stderr,
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Could not encode Rectangle (at %s)
|
|
\backslash
|
|
n
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
ec.failed_type ? ec.failed_type->name :
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
unknown
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
exit(65); /* better, EX_DATAERR */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
} else {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
fprintf(stderr,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Created %s with BER encoded Rectangle
|
|
\backslash
|
|
n
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
filename);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* Also print the constructed Rectangle XER encoded (XML) */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
xer_fprint(stdout, &asn_DEF_Rectangle, rectangle);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
return 0; /* Encoding finished successfully */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\end_deeper
|
|
\layout Enumerate
|
|
|
|
Compile all files together using C compiler (varies by platform):
|
|
\begin_deeper
|
|
\layout LyX-Code
|
|
|
|
|
|
\emph on
|
|
cc -I.
|
|
-o
|
|
\series bold
|
|
rencode
|
|
\series default
|
|
*.c
|
|
\end_deeper
|
|
\layout Enumerate
|
|
|
|
Voila! You have just created the BER and XER encoder of a Rectangle type,
|
|
named
|
|
\series bold
|
|
rencode
|
|
\series default
|
|
!
|
|
\layout Standard
|
|
|
|
|
|
\begin_inset ERT
|
|
status Collapsed
|
|
|
|
\layout Standard
|
|
|
|
\backslash
|
|
clearpage{}
|
|
\end_inset
|
|
|
|
|
|
\layout Section
|
|
|
|
|
|
\begin_inset LatexCommand \label{sec:A-Rectangle-Decoder}
|
|
|
|
\end_inset
|
|
|
|
A
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Rectangle
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
Decoder
|
|
\layout Standard
|
|
|
|
This example will help you to create a simple BER decoder of a simple
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Rectangle
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
type used throughout this document.
|
|
\layout Enumerate
|
|
|
|
Create a file named
|
|
\series bold
|
|
rectangle.asn1
|
|
\series default
|
|
with the following contents:
|
|
\begin_deeper
|
|
\layout LyX-Code
|
|
|
|
RectangleModule1 DEFINITIONS ::=
|
|
\layout LyX-Code
|
|
|
|
BEGIN
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
Rectangle ::= SEQUENCE {
|
|
\layout LyX-Code
|
|
|
|
height INTEGER,
|
|
\layout LyX-Code
|
|
|
|
width INTEGER
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
END
|
|
\end_deeper
|
|
\layout Enumerate
|
|
|
|
Compile it into the set of .c and .h files using asn1c compiler
|
|
\begin_inset LatexCommand \cite{ASN1C}
|
|
|
|
\end_inset
|
|
|
|
:
|
|
\begin_deeper
|
|
\layout LyX-Code
|
|
|
|
|
|
\emph on
|
|
asn1c -fnative-types
|
|
\series bold
|
|
\emph default
|
|
rectangle.asn1
|
|
\end_deeper
|
|
\layout Enumerate
|
|
|
|
Alternatively, use the Online ASN.1 compiler
|
|
\begin_inset LatexCommand \cite{AONL}
|
|
|
|
\end_inset
|
|
|
|
by uploading the
|
|
\series bold
|
|
rectangle.asn1
|
|
\series default
|
|
file into the Web form and unpacking the produced archive on your computer.
|
|
\layout Enumerate
|
|
|
|
By this time, you should have gotten multiple files in the current directory,
|
|
including the
|
|
\series bold
|
|
Rectangle.c
|
|
\series default
|
|
and
|
|
\series bold
|
|
Rectangle.h
|
|
\series default
|
|
.
|
|
\layout Enumerate
|
|
|
|
Create a main() routine which takes the binary input file, decodes it as
|
|
it were a BER-encoded Rectangle type, and prints out the text (XML) representat
|
|
ion of the Rectangle type.
|
|
Let's name the file
|
|
\series bold
|
|
main.c
|
|
\series default
|
|
:
|
|
\begin_inset ERT
|
|
status Collapsed
|
|
|
|
\layout Standard
|
|
|
|
\backslash
|
|
clearpage{}
|
|
\end_inset
|
|
|
|
|
|
\begin_deeper
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
#include <stdio.h>
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
#include <sys/types.h>
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
#include <Rectangle.h> /* Rectangle ASN.1 type */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
int main(int ac, char **av) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
char buf[1024]; /* Temporary buffer */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
Rectangle_t *rectangle = 0; /* Type to decode */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
asn_dec_rval_t rval; /* Decoder return value */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
FILE *fp; /* Input file handler */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
size_t size; /* Number of bytes read */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
char *filename; /* Input file name */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* Require a single filename argument */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
if(ac != 2) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
fprintf(stderr,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Usage: %s <file.ber>
|
|
\backslash
|
|
n
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
, av[0]);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
exit(64); /* better, EX_USAGE */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
} else {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
filename = av[1];
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* Open input file as read-only binary */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
fp = fopen(filename,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
rb
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
if(!fp) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
perror(filename);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
exit(66); /* better, EX_NOINPUT */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* Read up to the buffer size */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
size = fread(buf, 1, sizeof(buf), fp);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
fclose(fp);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
if(!size) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
fprintf(stderr,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
%s: Empty or broken
|
|
\backslash
|
|
n
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
, filename);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
exit(65); /* better, EX_DATAERR */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* Decode the input buffer as Rectangle type */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
rval = ber_decode(0, &asn_DEF_Rectangle,
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
(void **)&rectangle, buf, size);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
if(rval.code != RC_OK) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
fprintf(stderr,
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
%s: Broken Rectangle encoding at byte %ld
|
|
\backslash
|
|
n
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
filename, (long)rval.consumed);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
exit(65); /* better, EX_DATAERR */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* Print the decoded Rectangle type as XML */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
xer_fprint(stdout, &asn_DEF_Rectangle, rectangle);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
return 0; /* Decoding finished successfully */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\end_deeper
|
|
\layout Enumerate
|
|
|
|
Compile all files together using C compiler (varies by platform):
|
|
\begin_deeper
|
|
\layout LyX-Code
|
|
|
|
|
|
\emph on
|
|
cc -I.
|
|
-o
|
|
\series bold
|
|
rdecode
|
|
\series default
|
|
*.c
|
|
\end_deeper
|
|
\layout Enumerate
|
|
|
|
Voila! You have just created the BER decoder of a Rectangle type, named
|
|
|
|
\series bold
|
|
rdecode
|
|
\series default
|
|
!
|
|
\layout Chapter
|
|
|
|
Constraint validation examples
|
|
\layout Standard
|
|
|
|
This chapter shows how to define ASN.1 constraints and use the generated
|
|
validation code.
|
|
\layout Section
|
|
|
|
Adding constraints into
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Rectangle
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
type
|
|
\layout Standard
|
|
|
|
This example shows how to add basic constraints to the ASN.1 specification
|
|
and how to invoke the constraints validation code in your application.
|
|
\layout Enumerate
|
|
|
|
Create a file named
|
|
\series bold
|
|
rectangle.asn1
|
|
\series default
|
|
with the following contents:
|
|
\begin_deeper
|
|
\layout LyX-Code
|
|
|
|
RectangleModuleWithConstraints DEFINITIONS ::=
|
|
\layout LyX-Code
|
|
|
|
BEGIN
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
Rectangle ::= SEQUENCE {
|
|
\layout LyX-Code
|
|
|
|
height INTEGER (0..100), -- Value range constraint
|
|
\layout LyX-Code
|
|
|
|
width INTEGER (0..MAX) -- Makes width non-negative
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
END
|
|
\end_deeper
|
|
\layout Enumerate
|
|
|
|
Compile the file according to procedures shown in the previous chapter.
|
|
\layout Enumerate
|
|
|
|
Modify the Rectangle type processing routine (you can start with the main()
|
|
routine shown in the Section
|
|
\begin_inset LatexCommand \vref{sec:A-Rectangle-Decoder}
|
|
|
|
\end_inset
|
|
|
|
) by placing the following snippet of code
|
|
\emph on
|
|
before
|
|
\emph default
|
|
encoding and/or
|
|
\emph on
|
|
after
|
|
\emph default
|
|
decoding the Rectangle type
|
|
\begin_inset Foot
|
|
collapsed true
|
|
|
|
\layout Standard
|
|
|
|
Placing the constraint checking code
|
|
\emph on
|
|
before
|
|
\emph default
|
|
encoding helps to make sure you know the data is correct and within constraints
|
|
before sharing the data with anyone else.
|
|
\layout Standard
|
|
|
|
Placing the constraint checking code
|
|
\emph on
|
|
after
|
|
\emph default
|
|
decoding, but before any further action depending on the decoded data,
|
|
helps to make sure the application got the valid contents before making
|
|
use of it.
|
|
\end_inset
|
|
|
|
:
|
|
\begin_inset ERT
|
|
status Collapsed
|
|
|
|
\layout Standard
|
|
|
|
\backslash
|
|
clearpage{}
|
|
\end_inset
|
|
|
|
|
|
\begin_deeper
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
int ret; /* Return value */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
char errbuf[128]; /* Buffer for error message */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
size_t errlen = sizeof(errbuf); /* Size of the buffer */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* ...
|
|
here may go Rectangle decoding code ...
|
|
*/
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
ret = asn_check_constraints(&asn_DEF_Rectangle,
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
rectangle, errbuf, &errlen);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* assert(errlen < sizeof(errbuf)); // you may rely on that */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
if(ret) {
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
fprintf(stderr,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Constraint validation failed: %s
|
|
\backslash
|
|
n
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
errbuf /* errbuf is properly nul-terminated */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
);
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* exit(...); // Replace with appropriate action */
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
|
|
\layout LyX-Code
|
|
|
|
|
|
\size small
|
|
/* ...
|
|
here may go Rectangle encoding code ...
|
|
*/
|
|
\end_deeper
|
|
\layout Enumerate
|
|
|
|
Compile the resulting C code as shown in the previous chapters.
|
|
\layout Enumerate
|
|
|
|
Try to test the constraints checking code by assigning integer value 101
|
|
to the
|
|
\series bold
|
|
.height
|
|
\series default
|
|
member of the Rectangle structure, or a negative value to the
|
|
\series bold
|
|
.width
|
|
\series default
|
|
member.
|
|
In either case, the program should print
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Constraint validation failed
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
message, followed by the short explanation why validation did not succeed.
|
|
\layout Enumerate
|
|
|
|
Done.
|
|
\layout Part
|
|
|
|
|
|
\begin_inset LatexCommand \label{par:ASN.1-Basics}
|
|
|
|
\end_inset
|
|
|
|
ASN.1 Basics
|
|
\layout Chapter
|
|
|
|
|
|
\begin_inset LatexCommand \label{cha:Abstract-Syntax-Notation:}
|
|
|
|
\end_inset
|
|
|
|
Abstract Syntax Notation: ASN.1
|
|
\layout Standard
|
|
|
|
|
|
\emph on
|
|
This chapter defines some basic ASN.1 concepts and describes several most
|
|
widely used types.
|
|
It is by no means an authoritative or complete reference.
|
|
For more complete ASN.1 description, please refer to Olivier Dubuisson's
|
|
book
|
|
\begin_inset LatexCommand \cite{Dub00}
|
|
|
|
\end_inset
|
|
|
|
or the ASN.1 body of standards itself
|
|
\begin_inset LatexCommand \cite{ITU-T/ASN.1}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\layout Standard
|
|
|
|
The Abstract Syntax Notation One is used to formally describe the semantics
|
|
of data transmitted across the network.
|
|
Two communicating parties may have different formats of their native data
|
|
types (i.e.
|
|
number of bits in the integer type), thus it is important to have a way
|
|
to describe the data in a manner which is independent from the particular
|
|
machine's representation.
|
|
The ASN.1 specifications are used to achieve the following:
|
|
\layout Itemize
|
|
|
|
The specification expressed in the ASN.1 notation is a formal and precise
|
|
way to communicate the data semantics to human readers;
|
|
\layout Itemize
|
|
|
|
The ASN.1 specifications may be used as input for automatic compilers which
|
|
produce the code for some target language (C, C++, Java, etc) to encode
|
|
and decode the data according to some encoding rules (which are also defined
|
|
by the ASN.1 standard).
|
|
\layout Standard
|
|
|
|
Consider the following example:
|
|
\layout LyX-Code
|
|
|
|
Rectangle ::= SEQUENCE {
|
|
\layout LyX-Code
|
|
|
|
height INTEGER,
|
|
\layout LyX-Code
|
|
|
|
width INTEGER
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout Standard
|
|
|
|
This ASN.1 specification describes a constructed type,
|
|
\emph on
|
|
Rectangle
|
|
\emph default
|
|
, containing two integer fields.
|
|
This specification may tell the reader that there exists this kind of data
|
|
structure and that some entity may be prepared to send or receive it.
|
|
The question on
|
|
\emph on
|
|
how
|
|
\emph default
|
|
that entity is going to send or receive the
|
|
\emph on
|
|
encoded data
|
|
\emph default
|
|
is outside the scope of ASN.1.
|
|
For example, this data structure may be encoded according to some encoding
|
|
rules and sent to the destination using the TCP protocol.
|
|
The ASN.1 specifies several ways of encoding (or
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
serializing
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
, or
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
marshaling
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
) the data: BER, PER, XER and others, including CER and DER derivatives
|
|
from BER.
|
|
\layout Standard
|
|
|
|
The complete specification must be wrapped in a module, which looks like
|
|
this:
|
|
\layout LyX-Code
|
|
|
|
RectangleModule1
|
|
\layout LyX-Code
|
|
|
|
{ iso org(3) dod(6) internet(1) private(4)
|
|
\layout LyX-Code
|
|
|
|
enterprise(1) spelio(9363) software(1)
|
|
\layout LyX-Code
|
|
|
|
asn1c(5) docs(2) rectangle(1) 1 }
|
|
\layout LyX-Code
|
|
|
|
DEFINITIONS AUTOMATIC TAGS ::=
|
|
\layout LyX-Code
|
|
|
|
BEGIN
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
-- This is a comment which describes nothing.
|
|
\layout LyX-Code
|
|
|
|
Rectangle ::= SEQUENCE {
|
|
\layout LyX-Code
|
|
|
|
height INTEGER, -- Height of the rectangle
|
|
\layout LyX-Code
|
|
|
|
width INTEGER -- Width of the rectangle
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
END
|
|
\layout Standard
|
|
|
|
The module header consists of module name (RectangleModule1), the module
|
|
object identifier ({...}), a keyword
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
DEFINITIONS
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
, a set of module flags (AUTOMATIC TAGS) and
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
::= BEGIN
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
.
|
|
The module ends with an
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
END
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
statement.
|
|
\layout Section
|
|
|
|
Some of the ASN.1 Basic Types
|
|
\layout Subsection
|
|
|
|
The BOOLEAN type
|
|
\layout Standard
|
|
|
|
The BOOLEAN type models the simple binary TRUE/FALSE, YES/NO, ON/OFF or
|
|
a similar kind of two-way choice.
|
|
\layout Subsection
|
|
|
|
The INTEGER type
|
|
\layout Standard
|
|
|
|
The INTEGER type is a signed natural number type without any restrictions
|
|
on its size.
|
|
If the automatic checking on INTEGER value bounds are necessary, the subtype
|
|
constraints must be used.
|
|
\layout LyX-Code
|
|
|
|
SimpleInteger ::= INTEGER
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
-- An integer with a very limited range
|
|
\layout LyX-Code
|
|
|
|
SmallPositiveInt ::= INTEGER (0..127)
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
-- Integer, negative
|
|
\layout LyX-Code
|
|
|
|
NegativeInt ::= INTEGER (MIN..0)
|
|
\layout Subsection
|
|
|
|
The ENUMERATED type
|
|
\layout Standard
|
|
|
|
The ENUMERATED type is semantically equivalent to the INTEGER type with
|
|
some integer values explicitly named.
|
|
\layout LyX-Code
|
|
|
|
FruitId ::= ENUMERATED { apple(1), orange(2) }
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
-- The numbers in braces are optional,
|
|
\layout LyX-Code
|
|
|
|
-- the enumeration can be performed
|
|
\layout LyX-Code
|
|
|
|
-- automatically by the compiler
|
|
\layout LyX-Code
|
|
|
|
ComputerOSType ::= ENUMERATED {
|
|
\layout LyX-Code
|
|
|
|
FreeBSD, -- acquires value 0
|
|
\layout LyX-Code
|
|
|
|
Windows, -- acquires value 1
|
|
\layout LyX-Code
|
|
|
|
Solaris(5), -- remains 5
|
|
\layout LyX-Code
|
|
|
|
Linux, -- becomes 6
|
|
\layout LyX-Code
|
|
|
|
MacOS -- becomes 7
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout Subsection
|
|
|
|
The OCTET STRING type
|
|
\layout Standard
|
|
|
|
This type models the sequence of 8-bit bytes.
|
|
This may be used to transmit some opaque data or data serialized by other
|
|
types of encoders (i.e.
|
|
video file, photo picture, etc).
|
|
\layout Subsection
|
|
|
|
The OBJECT IDENTIFIER type
|
|
\layout Standard
|
|
|
|
The OBJECT IDENTIFIER is used to represent the unique identifier of any
|
|
object, starting from the very root of the registration tree.
|
|
If your organization needs to uniquely identify something (a router, a
|
|
room, a person, a standard, or whatever), you are encouraged to get your
|
|
own identification subtree at
|
|
\begin_inset LatexCommand \htmlurl{http://www.iana.org/protocols/forms.htm}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
\layout Standard
|
|
|
|
For example, the very first ASN.1 module in this Chapter (RectangleModule1)
|
|
has the following OBJECT IDENTIFIER: 1 3 6 1 4 1 9363 1 5 2 1 1.
|
|
\layout LyX-Code
|
|
|
|
ExampleOID ::= OBJECT IDENTIFIER
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
rectangleModule1-oid ExampleOID
|
|
\layout LyX-Code
|
|
|
|
::= { 1 3 6 1 4 1 9363 1 5 2 1 1 }
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
-- An identifier of the Internet.
|
|
\layout LyX-Code
|
|
|
|
internet-id OBJECT IDENTIFIER
|
|
\layout LyX-Code
|
|
|
|
::= { iso(1) identified-organization(3)
|
|
\layout LyX-Code
|
|
|
|
dod(6) internet(1) }
|
|
\layout Standard
|
|
|
|
As you see, names are optional.
|
|
\layout Subsection
|
|
|
|
The RELATIVE-OID type
|
|
\layout Standard
|
|
|
|
The RELATIVE-OID type has the semantics of a subtree of an OBJECT IDENTIFIER.
|
|
There may be no need to repeat the whole sequence of numbers from the root
|
|
of the registration tree where the only thing of interest is some of the
|
|
tree's subsequence.
|
|
\layout LyX-Code
|
|
|
|
this-document RELATIVE-OID ::= { docs(2) usage(1) }
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
this-example RELATIVE-OID ::= {
|
|
\layout LyX-Code
|
|
|
|
this-document assorted-examples(0) this-example(1) }
|
|
\layout Section
|
|
|
|
Some of the ASN.1 String Types
|
|
\layout Subsection
|
|
|
|
The IA5String type
|
|
\layout Standard
|
|
|
|
This is essentially the ASCII, with 128 character codes available (7 lower
|
|
bits of an 8-bit byte).
|
|
\layout Subsection
|
|
|
|
The UTF8String type
|
|
\layout Standard
|
|
|
|
This is the character string which encodes the full Unicode range (4 bytes)
|
|
using multibyte character sequences.
|
|
\layout Subsection
|
|
|
|
The NumericString type
|
|
\layout Standard
|
|
|
|
This type represents the character string with the alphabet consisting of
|
|
numbers (
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
0
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
to
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
9
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
) and a space.
|
|
\layout Subsection
|
|
|
|
The PrintableString type
|
|
\layout Standard
|
|
|
|
The character string with the following alphabet: space,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
'
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
(single quote),
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
(
|
|
\series default
|
|
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
)
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
+
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
,
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
(comma),
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
-
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
.
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
/
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
, digits (
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
0
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
to
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
9
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
),
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
:
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
=
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
?
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
, upper-case and lower-case letters (
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
A
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
to
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
Z
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
and
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
a
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
to
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
z
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
).
|
|
\layout Subsection
|
|
|
|
The VisibleString type
|
|
\layout Standard
|
|
|
|
The character string with the alphabet which is more or less a subset of
|
|
ASCII between the space and the
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
~
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
symbol (tilde).
|
|
\layout Standard
|
|
|
|
Alternatively, the alphabet may be described as the PrintableString alphabet
|
|
presented earlier, plus the following characters:
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
!
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
#
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
$
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
%
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
&
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
*
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
;
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
<
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
>
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
[
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
|
|
\backslash
|
|
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
]
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
^
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
_
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
`
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
(single left quote),
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
{
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
|
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
}
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
,
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
|
|
\series bold
|
|
~
|
|
\series default
|
|
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
.
|
|
\layout Section
|
|
|
|
ASN.1 Constructed Types
|
|
\layout Subsection
|
|
|
|
The SEQUENCE type
|
|
\layout Standard
|
|
|
|
This is an ordered collection of other simple or constructed types.
|
|
The SEQUENCE constructed type resembles the C
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
struct
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
statement.
|
|
\layout LyX-Code
|
|
|
|
Address ::= SEQUENCE {
|
|
\layout LyX-Code
|
|
|
|
-- The apartment number may be omitted
|
|
\layout LyX-Code
|
|
|
|
apartmentNumber NumericString OPTIONAL,
|
|
\layout LyX-Code
|
|
|
|
streetName PrintableString,
|
|
\layout LyX-Code
|
|
|
|
cityName PrintableString,
|
|
\layout LyX-Code
|
|
|
|
stateName PrintableString,
|
|
\layout LyX-Code
|
|
|
|
-- This one may be omitted too
|
|
\layout LyX-Code
|
|
|
|
zipNo NumericString OPTIONAL
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout Subsection
|
|
|
|
The SET type
|
|
\layout Standard
|
|
|
|
This is a collection of other simple or constructed types.
|
|
Ordering is not important.
|
|
The data may arrive in the order which is different from the order of specifica
|
|
tion.
|
|
Data is encoded in the order not necessarily corresponding to the order
|
|
of specification.
|
|
\layout Subsection
|
|
|
|
The CHOICE type
|
|
\layout Standard
|
|
|
|
This type is just a choice between the subtypes specified in it.
|
|
The CHOICE type contains at most one of the subtypes specified, and it
|
|
is always implicitly known which choice is being decoded or encoded.
|
|
This one resembles the C
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
union
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
statement.
|
|
\layout Standard
|
|
|
|
The following type defines a response code, which may be either an integer
|
|
code or a boolean
|
|
\begin_inset Quotes sld
|
|
\end_inset
|
|
|
|
true
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
/
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
false
|
|
\begin_inset Quotes srd
|
|
\end_inset
|
|
|
|
code.
|
|
\layout LyX-Code
|
|
|
|
ResponseCode ::= CHOICE {
|
|
\layout LyX-Code
|
|
|
|
intCode INTEGER,
|
|
\layout LyX-Code
|
|
|
|
boolCode BOOLEAN
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout LyX-Code
|
|
|
|
\layout Subsection
|
|
|
|
The SEQUENCE OF type
|
|
\layout Standard
|
|
|
|
This one is the list (array) of simple or constructed types:
|
|
\layout LyX-Code
|
|
|
|
-- Example 1
|
|
\layout LyX-Code
|
|
|
|
ManyIntegers ::= SEQUENCE OF INTEGER
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
-- Example 2
|
|
\layout LyX-Code
|
|
|
|
ManyRectangles ::= SEQUENCE OF Rectangle
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
-- More complex example:
|
|
\layout LyX-Code
|
|
|
|
-- an array of structures defined in place.
|
|
\layout LyX-Code
|
|
|
|
ManyCircles ::= SEQUENCE OF SEQUENCE {
|
|
\layout LyX-Code
|
|
|
|
radius INTEGER
|
|
\layout LyX-Code
|
|
|
|
}
|
|
\layout Subsection
|
|
|
|
The SET OF type
|
|
\layout Standard
|
|
|
|
The SET OF type models the bag of structures.
|
|
It resembles the SEQUENCE OF type, but the order is not important: i.e.
|
|
the elements may arrive in the order which is not necessarily the same
|
|
as the in-memory order on the remote machines.
|
|
\layout LyX-Code
|
|
|
|
-- A set of structures defined elsewhere
|
|
\layout LyX-Code
|
|
|
|
SetOfApples :: SET OF Apple
|
|
\layout LyX-Code
|
|
|
|
|
|
\layout LyX-Code
|
|
|
|
-- Set of integers encoding the kind of a fruit
|
|
\layout LyX-Code
|
|
|
|
FruitBag ::= SET OF ENUMERATED { apple, orange }
|
|
\layout Bibliography
|
|
\bibitem [ASN1C]{ASN1C}
|
|
|
|
The Open Source ASN.1 Compiler.
|
|
|
|
\begin_inset LatexCommand \htmlurl{http://lionet.info/asn1c}
|
|
|
|
\end_inset
|
|
|
|
|
|
\layout Bibliography
|
|
\bibitem [AONL]{AONL}
|
|
|
|
Online ASN.1 Compiler.
|
|
|
|
\begin_inset LatexCommand \htmlurl{http://lionet.info/asn1c/asn1c.cgi}
|
|
|
|
\end_inset
|
|
|
|
|
|
\layout Bibliography
|
|
\bibitem [Dub00]{Dub00}
|
|
|
|
Olivier Dubuisson ---
|
|
\emph on
|
|
ASN.1 Communication between heterogeneous systems
|
|
\emph default
|
|
--- Morgan Kaufmann Publishers, 2000.
|
|
|
|
\begin_inset LatexCommand \htmlurl{http://asn1.elibel.tm.fr/en/book/}
|
|
|
|
\end_inset
|
|
|
|
.
|
|
ISBN:0-12-6333361-0.
|
|
\layout Bibliography
|
|
\bibitem [ITU-T/ASN.1]{ITU-T/ASN.1}
|
|
|
|
ITU-T Study Group 17 -- Languages for Telecommunication Systems
|
|
\begin_inset LatexCommand \url{http://www.itu.int/ITU-T/studygroups/com17/languages/}
|
|
|
|
\end_inset
|
|
|
|
|
|
\the_end
|