IDNCONV(1) IDNCONV(1)
NAME
idnconv - codeset converter for named.conf and zone master files
SYNOPSIS
idnconv [options..] [file...]
DESCRIPTION
idnconv is a codeset converter for named configuration files and zone
master files. idnconv performs codeset conversion specified either by
the command-line arguments or by the configuration file, and writes the
converted text to stdout.
If file name is specified, idnconv converts the contents of the file.
Otherwise, idnconv converts stdin.
Since idnconv is specifically designed for converting internatinalized
domain names, it may not be suitable as a general codeset converter.
OPERATION MODES
idnconv has two operation modes.
One is a mode to convert local-encoded domain names to IDN-encoded one.
Usually this mode is used for preparing domain names to be listed in
named configuration files or zone master files. In this mode, the fol
lowing processes are performed in addition to the codeset (encoding)
conversion.
- local mapping
- standard domain name preperation (NAMEPREP)
The other mode is a reverse conversion, from IDN-encoded domain name to
local-encoded domain names. In this mode, local mapping and NAMEPREP
are not performed since IDN-encoded names should already be normalized.
Instead, a check is done in order to make sure the IDN-encoded domain
name is properly NAMEPREPed. If it is not, the name will be output in
IDN encoding, not in the local encoding.
OPTIONS
Normally idnconv reads systems default configuration file (idn.conf)
and performs conversion or name preparation according to the parameters
specified in the file. You can override the setting in the configura
tion file by various command line options below.
-in in-code, -i in-code
Specify the codeset name of the input text. Any of the following
codeset names can be specified.
Any codeset names which iconv_open() library function accepts
Punycode
UTF-8
Any alias names for the above, defined by the codeset alias file.
If this option is not specified, the default codeset is determined
from the locale in normal conversion mode. In reverse conversion
mode, the default codeset is the IDN encoding specified by the con
figuration file (idn-encoding entry).
-out out-code, -o out-code
Specify the codeset name of the output text. out-code can be any
codeset name that can be specified for -in option.
If this option is not specified, the default is the IDN encoding
specified by the configuration file (idn-encoding entry) in
normal conversion mode. In reverse conversion mode, the default
codeset is determined from the locale.
-conf path, -c path
Specify the pathname of idnkit configuration file (idn.conf).
If not specified, systems default file is used, unless -noconf
option is specified.
-noconf, -C
Specify that no configuration file is to be used.
-reverse, -r
Specify reverse conversion mode.
If this option is not specified, the normal conversion mode is
used.
-nameprep version, -n version
Specify the version of NAMEPREP. The following is a list of cur
rently available versions.
RFC3491
Perform NAMEPREP according to the RFC3491 rfc-3491.txt.
-nonameprep, -N
Specify to skip NAMEPREP process (or NAMEPREP verification process
in the reverse conversion mode). This option implies -nounas
signcheck and -nobidicheck.
-localmap map
Specify the name of local mapping rule. Currently, following maps
are available.
RFC3491
Use the list of mappings specified by RFC3491.
filemap:path
Use list of mappings specified by mapfile path. See
idn.conf(5) for the format of a mapfile.
This option can be specified more than once. In that case, each
mapping will be performed in the order of the specification.
-nounassigncheck, -U
Skip unassigned codepoint check.
-nobidicheck, -B
Skip bidi character check.
-nolengthcheck
Do not check label length of normal conversion result. This option
is only meaningful in the normal conversion mode.
-noasciicheck, -A
Do not check ASCII range characters. This option is only meaning
ful in the normal conversion mode.
-noroundtripcheck
Do not perform round trip check. This option is only meaningful in
the reverse conversion mode.
-delimiter codepoint
Specify the character to be mapped to domain name delimiter
(period). This option can be specified more than once in order to
specify multiple characters.
This option is only meaningful in the normal conversion mode.
-whole, -w
Perform local mapping, nameprep and conversion to output codeset
for the entire input text. If this option is not specified, only
non-ASCII characters and their surrounding texts will be processed.
See NORAML CONVERSION MECHANISM and REVERSE CONVERSION MECHA
NISM for details.
-alias path, -a path
Specify a codeset alias file. It is a simple text file, where each
line has a pair of alias name and real name separated by one or
more white spaces like below:
alias-codeset-name real-codeset-name
Lines starting with # are treated as comments.
-flush
Force line-buffering mode.
-version, -v
Print version information and quit.
LOCAL CODESET
idnconv guesses local codeset from locale and environment variables.
See the LOCAL CODESET section in idn.conf(5) for more details.
NORMAL CONVERSION MECHANISM
idnconv performs conversion line by line. Here describes how idnconv
does its job for each line.
1. read a line from input text
2. convert the line to UTF-8
idnconv converts the line from local encoding to UTF-8.
3. find internationalized domain names
If the -whole (or -w) option is specified, the entire line is
assumed as an internationalized domain name. Otherwise, idnconv
recognizes any character sequences having the following properties
in the line as internationalized domain names.
containing at least one non-ASCII character, and
consisting of legal domain name characters (alphabets, digits,
hypens), non-ASCII characters and period.
4. convert internationalized domain names to ACE
For each internationalized domain name found in the line, idnconv
converts the name to ACE. The details about the conversion proce
dure is:
4.1. delimiter mapping
Substibute certain characters specified as domain name delim
iter with period.
4.2. local mapping
Perform local mapping. If the local mapping is specified by
command line option -localmap, the specified mapping rule is
applied. Otherwise, find the mapping rule from the configura
tion file which matches to the TLD of the name, and perform
mapping according to the matched rule.
This step is skipped if the -nolocalmap (or -L) option is spec
ified.
4.3. NAMEPREP
Perform name preparation (NAMEPREP). Mapping, normalization,
prohibited character checking, unassigned codepoint checking,
bidirectional character checking are done in that order. If
the prohibited character check, unassigned codepoint check, or
bidi character check fails, the normal conversion procedure
aborts.
This step is skipped if the -nonameprep (or -N) option is spec
ified.
4.4. ASCII character checking
Checks ASCII range character in the domain name. the normal
conversion procedure aborts, if the domain name has a label
beginning or end with hyphen (U+002D) or it contains ASCII
range character except for alphanumeric and hyphen,
This step is skipped if the -noasciicheck (or -A) option is
specified.
4.5. ACE conversion
Convert the string to ACE.
4.6. label length checking
The normal conversion procedure aborts, if the domain name has
an empty label or too long label (64 characters or more).
This step is skipped if the -nolengthcheck option is specified.
5. output the result
REVERSE CONVERSION MECHANISM
This is like the normal conversion mechanism, but they are not symmet
ric. idnconv does its job for each line.
1. read a line from input text
2. convert the line to UTF-8
idnconv converts the line from local encoding to UTF-8.
3. find internationalized domain names
If the -whole (or -w) option is specified, the entire line is
assumed as an internationalized domain name. Otherwise, idnconv
decodes any valid ASCII domain names including ACE names in the
line.
4. convert domain names to local encoding
Then, idnconv decodes the domain names. The decode procedure con
sists of the following steps.
4.1. Delimiter mapping
Substibute certain characters specified as domain name delim
iter with period.
4.2. NAMEPREP
Perform name preparation (NAMEPREP) for each label in the
domain name. Mapping, normalization, prohibited character
checking, unassigned codepoint checking, bidirectional charac
ter checking are done in that order. If the prohibited charac
ter check, unassigned codepoint check, or bidi character check
fails, disqualified labels are restored to original input
strings and further conversion on those labels are not per
formed.
This step is skipped if the -nonameprep (or -N) option is spec
ified.
4.3. ACE conversion
Convert the string from ACE to UTF-8.
4.4. Round trip checkning
For each label, perform the normal conversion and compare it
with the result of the step 4.2. This check succeeds, if they
are equivalent strings. In case of failure, disqualified
labels are restored to original input strings and further con
version on those labels are not performed.
This step is skipped if the -noroundtripcheck option is speci
fied.
4.5. local encoding conversion
Convert the result of the step 4.3. from UTF-8 to local encod
ing. If a label in the domain name contains a character which
cannot be represented in the local encoding, the label is
restored to the original input string.
5. output the result
FILE MANAGEMENT
Maybe the best way to manage named.conf or zone master files that con
tains internationalized domain name is to keep them in your local code
set so that they can be edited with your favorite editor, and generate
a version in the IDN encoding using idnconv.
make is a convenient tool for this purpose. Suppose the local code
set version has suffix .lc, and its ACE version has suffix .ace.
The following Makefile enables you to generate ACE version from local
codeset version by just typing make.
.SUFFIXES: .lc .ace
.lc.ace:
idnconv -in $(LOCALCODE) -out $(IDNCODE) \
$(IDNCONVOPT) $< > $@
LOCALCODE = EUC-JP
IDNCODE = Punycode
IDNCONVOPT =
DESTFILES = db.zone1.ace db.zone2.ace
all: $(DESTFILES)
SEE ALSO
idn.conf(5), iconv(3)
BUGS
The automatic input-code selection depends on your system, and some
times it cannot guess or guess wrong. It is better to explicitly spec
ify it using -in option.
Mar 3, 2001 IDNCONV(1)
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