kea/src/lib/dns/tests/testdata/gen-wiredata.py.in

#!@PYTHON@

# Copyright (C) 2010  Internet Systems Consortium.
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SYSTEMS CONSORTIUM
# DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
# INTERNET SYSTEMS CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
# FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
# WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

import configparser, re, time, socket, sys
from datetime import datetime
from optparse import OptionParser

re_hex = re.compile(r'^0x[0-9a-fA-F]+')
re_decimal = re.compile(r'^\d+$')
re_string = re.compile(r"\'(.*)\'$")

dnssec_timefmt = '%Y%m%d%H%M%S'

dict_qr = { 'query' : 0, 'response' : 1 }
dict_opcode = { 'query' : 0, 'iquery' : 1, 'status' : 2, 'notify' : 4,
                'update' : 5 }
rdict_opcode = dict([(dict_opcode[k], k.upper()) for k in dict_opcode.keys()])
dict_rcode = { 'noerror' : 0, 'formerr' : 1, 'servfail' : 2, 'nxdomain' : 3,
               'notimp' : 4, 'refused' : 5, 'yxdomain' : 6, 'yxrrset' : 7,
               'nxrrset' : 8, 'notauth' : 9, 'notzone' : 10 }
rdict_rcode = dict([(dict_rcode[k], k.upper()) for k in dict_rcode.keys()])
dict_rrtype = { 'none' : 0, 'a' : 1, 'ns' : 2, 'md' : 3, 'mf' : 4, 'cname' : 5,
                'soa' : 6, 'mb' : 7, 'mg' : 8, 'mr' : 9, 'null' : 10,
                'wks' : 11, 'ptr' : 12, 'hinfo' : 13, 'minfo' : 14, 'mx' : 15,
                'txt' : 16, 'rp' : 17, 'afsdb' : 18, 'x25' : 19, 'isdn' : 20,
                'rt' : 21, 'nsap' : 22, 'nsap_tr' : 23, 'sig' : 24, 'key' : 25,
                'px' : 26, 'gpos' : 27, 'aaaa' : 28, 'loc' : 29, 'nxt' : 30,
                'srv' : 33, 'naptr' : 35, 'kx' : 36, 'cert' : 37, 'a6' : 38,
                'dname' : 39, 'opt' : 41, 'apl' : 42, 'ds' : 43, 'sshfp' : 44,
                'ipseckey' : 45, 'rrsig' : 46, 'nsec' : 47, 'dnskey' : 48,
                'dhcid' : 49, 'nsec3' : 50, 'nsec3param' : 51, 'hip' : 55,
                'spf' : 99, 'unspec' : 103, 'tkey' : 249, 'tsig' : 250,
                'dlv' : 32769, 'ixfr' : 251, 'axfr' : 252, 'mailb' : 253,
                'maila' : 254, 'any' : 255 }
rdict_rrtype = dict([(dict_rrtype[k], k.upper()) for k in dict_rrtype.keys()])
dict_rrclass = { 'in' : 1, 'ch' : 3, 'hs' : 4, 'any' : 255 }
rdict_rrclass = dict([(dict_rrclass[k], k.upper()) for k in \
                          dict_rrclass.keys()])
dict_algorithm = { 'rsamd5' : 1, 'dh' : 2, 'dsa' : 3, 'ecc' : 4,
                   'rsasha1' : 5 }
dict_nsec3_algorithm = { 'reserved' : 0, 'sha1' : 1 }
rdict_algorithm = dict([(dict_algorithm[k], k.upper()) for k in \
                            dict_algorithm.keys()])
rdict_nsec3_algorithm = dict([(dict_nsec3_algorithm[k], k.upper()) for k in \
                                  dict_nsec3_algorithm.keys()])

header_xtables = { 'qr' : dict_qr, 'opcode' : dict_opcode,
                   'rcode' : dict_rcode }
question_xtables = { 'rrtype' : dict_rrtype, 'rrclass' : dict_rrclass }
rrsig_xtables = { 'algorithm' : dict_algorithm }

def parse_value(value, xtable = {}):
    if re.search(re_hex, value):
        return int(value, 16)
    if re.search(re_decimal, value):
        return int(value)
    m = re.match(re_string, value)
    if m:
        return m.group(1)
    lovalue = value.lower()
    if lovalue in xtable:
        return xtable[lovalue]
    return value

def code_totext(code, dict):
    if code in dict.keys():
        return dict[code] + '(' + str(code) + ')'
    return str(code)

def encode_name(name, absolute=True):
    # make sure the name is dot-terminated.  duplicate dots will be ignored
    # below.
    name += '.'
    labels = name.split('.')
    wire = ''
    for l in labels:
        if len(l) > 4 and l[0:4] == 'ptr=':
            # special meta-syntax for compression pointer
            wire += '%04x' % (0xc000 | int(l[4:]))
            break
        if absolute or len(l) > 0:
            wire += '%02x' % len(l)
            wire += ''.join(['%02x' % ord(ch) for ch in l])
        if len(l) == 0:
            break
    return wire

def encode_string(name, len=None):
    if type(name) is int and len is not None:
        return '%0.*x' % (len * 2, name)
    return ''.join(['%02x' % ord(ch) for ch in name])

def count_namelabels(name):
    if name == '.':             # special case
        return 0
    m = re.match('^(.*)\.$', name)
    if m:
        name = m.group(1)
    return len(name.split('.'))

def get_config(config, section, configobj, xtables = {}):
    try:
        for field in config.options(section):
            value = config.get(section, field)
            if field in xtables.keys():
                xtable = xtables[field]
            else:
                xtable = {}
            configobj.__dict__[field] = parse_value(value, xtable)
    except configparser.NoSectionError:
        return False
    return True

def print_header(f, input_file):
    f.write('''###
### This data file was auto-generated from ''' + input_file + '''
###
''')

class Name:
    name = 'example.com'
    pointer = None                # no compression by default
    def dump(self, f):
        name = self.name
        if self.pointer is not None:
            if len(name) > 0 and name[-1] != '.':
                name += '.'
            name += 'ptr=%d' % self.pointer
        name_wire = encode_name(name)
        f.write('\n# DNS Name: %s' % self.name)
        if self.pointer is not None:
            f.write(' + compression pointer: %d' % self.pointer)
        f.write('\n')
        f.write('%s' % name_wire)
        f.write('\n')

class DNSHeader:
    id = 0x1035
    (qr, aa, tc, rd, ra, ad, cd) = 0, 0, 0, 0, 0, 0, 0
    mbz = 0
    rcode = 0                   # noerror
    opcode = 0                  # query
    (qdcount, ancount, nscount, arcount) = 1, 0, 0, 0
    def dump(self, f):
        f.write('\n# Header Section\n')
        f.write('# ID=' + str(self.id))
        f.write(' QR=' + ('Response' if self.qr else 'Query'))
        f.write(' Opcode=' + code_totext(self.opcode, rdict_opcode))
        f.write(' Rcode=' + code_totext(self.rcode, rdict_rcode))
        f.write('%s' % (' AA' if self.aa else ''))
        f.write('%s' % (' TC' if self.tc else ''))
        f.write('%s' % (' RD' if self.rd else ''))
        f.write('%s' % (' AD' if self.ad else ''))
        f.write('%s' % (' CD' if self.cd else ''))
        f.write('\n')
        f.write('%04x ' % self.id)
        flag_and_code = 0
        flag_and_code |= (self.qr << 15 | self.opcode << 14 | self.aa << 10 |
                          self.tc << 9 | self.rd << 8 | self.ra << 7 |
                          self.mbz << 6 | self.ad << 5 | self.cd << 4 |
                          self.rcode)
        f.write('%04x\n' % flag_and_code)
        f.write('# QDCNT=%d, ANCNT=%d, NSCNT=%d, ARCNT=%d\n' %
                (self.qdcount, self.ancount, self.nscount, self.arcount))
        f.write('%04x %04x %04x %04x\n' % (self.qdcount, self.ancount,
                                           self.nscount, self.arcount))

class DNSQuestion:
    name = 'example.com.'
    rrtype = parse_value('A', dict_rrtype)
    rrclass = parse_value('IN', dict_rrclass)
    def dump(self, f):
        f.write('\n# Question Section\n')
        f.write('# QNAME=%s QTYPE=%s QCLASS=%s\n' %
                (self.name,
                 code_totext(self.rrtype, rdict_rrtype),
                 code_totext(self.rrclass, rdict_rrclass)))
        f.write(encode_name(self.name))
        f.write(' %04x %04x\n' % (self.rrtype, self.rrclass))

class EDNS:
    name = '.'
    udpsize = 4096
    extrcode = 0
    version = 0
    do = 0
    mbz = 0
    rdlen = 0
    def dump(self, f):
        f.write('\n# EDNS OPT RR\n')
        f.write('# NAME=%s TYPE=%s UDPSize=%d ExtRcode=%s Version=%s DO=%d\n' %
                (self.name, code_totext(dict_rrtype['opt'], rdict_rrtype),
                 self.udpsize, self.extrcode, self.version,
                 1 if self.do else 0))
        
        code_vers = (self.extrcode << 8) | (self.version & 0x00ff)
        extflags = (self.do << 15) | (self.mbz & 0x8000)
        f.write('%s %04x %04x %04x %04x\n' %
                (encode_name(self.name), dict_rrtype['opt'], self.udpsize,
                 code_vers, extflags))
        f.write('# RDLEN=%d\n' % self.rdlen)
        f.write('%04x\n' % self.rdlen)

class RR:
    '''This is a base class for various types of RR test data.
    For each RR type (A, AAAA, NS, etc), we define a derived class of RR
    to dump type specific RDATA parameters.  This class defines parameters
    common to all types of RDATA, namely the owner name, RR class and TTL.
    The dump() method of derived classes are expected to call dump_header(),
    whose default implementation is provided in this class.  This method
    decides whether to dump the test data as an RR (with name, type, class)
    or only as RDATA (with its length), and dumps the corresponding data
    via the specified file object.

    By convention we assume derived classes are named after the common
    standard mnemonic of the corresponding RR types.  For example, the
    derived class for the RR type SOA should be named "SOA".

    Configurable parameters are as follows:
    - as_rr (bool): Whether or not the data is to be dumped as an RR.  False
      by default.
    - rr_class (string): The RR class of the data.  Only meaningful when the
      data is dumped as an RR.  Default is 'IN'.
    - rr_ttl (integer): The TTL value of the RR.  Only meaningful when the
      data is dumped as an RR.  Default is 86400 (1 day).
    '''

    def __init__(self):
        self.as_rr = False
        # only when as_rr is True, same for class/TTL:
        self.rr_name = 'example.com'
        self.rr_class = 'IN'
        self.rr_ttl = 86400
    def dump_header(self, f, rdlen):
        type_txt = self.__class__.__name__
        type_code = parse_value(type_txt, dict_rrtype)
        if self.as_rr:
            rrclass = parse_value(self.rr_class, dict_rrclass)
            f.write('\n# %s RR (QNAME=%s Class=%s TTL=%d RDLEN=%d)\n' %
                    (type_txt, self.rr_name,
                     code_totext(rrclass, rdict_rrclass), self.rr_ttl, rdlen))
            f.write('%s %04x %04x %08x %04x\n' %
                    (encode_name(self.rr_name), type_code, rrclass,
                     self.rr_ttl, rdlen))
        else:
            f.write('\n# %s RDATA (RDLEN=%d)\n' % (type_txt, rdlen))
            f.write('%04x\n' % rdlen)

class A(RR):
    rdlen = 4                   # fixed by default
    address = '192.0.2.1'

    def dump(self, f):
        self.dump_header(f, self.rdlen)
        f.write('# Address=%s\n' % (self.address))
        bin_address = socket.inet_aton(self.address)
        f.write('%02x%02x%02x%02x\n' % (bin_address[0], bin_address[1],
                                        bin_address[2], bin_address[3]))

class NS(RR):
    rdlen = None                   # auto calculate
    nsname = 'ns.example.com'

    def dump(self, f):
        nsname_wire = encode_name(self.nsname)
        if self.rdlen is None:
            self.rdlen = len(nsname_wire) / 2
        self.dump_header(f, self.rdlen)
        f.write('# NS name=%s\n' % (self.nsname))
        f.write('%s\n' % nsname_wire)

class SOA:
    # this currently doesn't support name compression within the RDATA.
    rdlen = -1                  # auto-calculate
    mname = 'ns.example.com'
    rname = 'root.example.com'
    serial = 2010012601
    refresh = 3600
    retry = 300
    expire = 3600000
    minimum = 1200
    def dump(self, f):
        mname_wire = encode_name(self.mname)
        rname_wire = encode_name(self.rname)
        rdlen = self.rdlen
        if rdlen < 0:
            rdlen = int(20 + len(mname_wire) / 2 + len(str(rname_wire)) / 2)
        f.write('\n# SOA RDATA (RDLEN=%d)\n' % rdlen)
        f.write('%04x\n' % rdlen);
        f.write('# NNAME=%s RNAME=%s\n' % (self.mname, self.rname))
        f.write('%s %s\n' % (mname_wire, rname_wire))
        f.write('# SERIAL(%d) REFRESH(%d) RETRY(%d) EXPIRE(%d) MINIMUM(%d)\n' %
                (self.serial, self.refresh, self.retry, self.expire,
                 self.minimum))
        f.write('%08x %08x %08x %08x %08x\n' % (self.serial, self.refresh,
                                                self.retry, self.expire,
                                                self.minimum))

class TXT:
    rdlen = -1                  # auto-calculate
    nstring = 1                 # number of character-strings
    stringlen = -1              # default string length, auto-calculate
    string = 'Test String'      # default string
    def dump(self, f):
        stringlen_list = []
        string_list = []
        wirestring_list = []
        for i in range(0, self.nstring):
            key_string = 'string' + str(i)
            if key_string in self.__dict__:
                string_list.append(self.__dict__[key_string])
            else:
                string_list.append(self.string)
            wirestring_list.append(encode_string(string_list[-1]))
            key_stringlen = 'stringlen' + str(i)
            if key_stringlen in self.__dict__:
                stringlen_list.append(self.__dict__[key_stringlen])
            else:
                stringlen_list.append(self.stringlen)
            if stringlen_list[-1] < 0:
                stringlen_list[-1] = int(len(wirestring_list[-1]) / 2)
        rdlen = self.rdlen
        if rdlen < 0:
            rdlen = int(len(''.join(wirestring_list)) / 2) + self.nstring
        f.write('\n# TXT RDATA (RDLEN=%d)\n' % rdlen)
        f.write('%04x\n' % rdlen);
        for i in range(0, self.nstring):
            f.write('# String Len=%d, String=\"%s\"\n' %
                    (stringlen_list[i], string_list[i]))
            f.write('%02x%s%s\n' % (stringlen_list[i],
                                    ' ' if len(wirestring_list[i]) > 0 else '',
                                    wirestring_list[i]))

class RP:
    '''Implements rendering RP RDATA in the wire format.
    Configurable parameters are as follows:
    - rdlen: 16-bit RDATA length.  If omitted, the accurate value is auto
      calculated and used; if negative, the RDLEN field will be omitted from
      the output data.
    - mailbox: The mailbox field.
    - text: The text field.
    All of these parameters have the default values and can be omitted.
    '''
    rdlen = None                # auto-calculate
    mailbox = 'root.example.com'
    text = 'rp-text.example.com'
    def dump(self, f):
        mailbox_wire = encode_name(self.mailbox)
        text_wire = encode_name(self.text)
        if self.rdlen is None:
            self.rdlen = (len(mailbox_wire) + len(text_wire)) / 2
        else:
            self.rdlen = int(self.rdlen)
        if self.rdlen >= 0:
            f.write('\n# RP RDATA (RDLEN=%d)\n' % self.rdlen)
            f.write('%04x\n' % self.rdlen)
        else:
            f.write('\n# RP RDATA (RDLEN omitted)\n')
        f.write('# MAILBOX=%s TEXT=%s\n' % (self.mailbox, self.text))
        f.write('%s %s\n' % (mailbox_wire, text_wire))

class NSECBASE:
    '''Implements rendering NSEC/NSEC3 type bitmaps commonly used for
    these RRs.  The NSEC and NSEC3 classes will be inherited from this
    class.'''
    nbitmap = 1                 # number of bitmaps
    block = 0
    maplen = None              # default bitmap length, auto-calculate
    bitmap = '040000000003'     # an arbtrarily chosen bitmap sample
    def dump(self, f):
        # first, construct the bitmpa data
        block_list = []
        maplen_list = []
        bitmap_list = []
        for i in range(0, self.nbitmap):
            key_bitmap = 'bitmap' + str(i)
            if key_bitmap in self.__dict__:
                bitmap_list.append(self.__dict__[key_bitmap])
            else:
                bitmap_list.append(self.bitmap)
            key_maplen = 'maplen' + str(i)
            if key_maplen in self.__dict__:
                maplen_list.append(self.__dict__[key_maplen])
            else:
                maplen_list.append(self.maplen)
            if maplen_list[-1] is None: # calculate it if not specified
                maplen_list[-1] = int(len(bitmap_list[-1]) / 2)
            key_block = 'block' + str(i)
            if key_block in self.__dict__:
               block_list.append(self.__dict__[key_block])
            else:
                block_list.append(self.block)

        # dump RR-type specific part (NSEC or NSEC3)
        self.dump_fixedpart(f, 2 * self.nbitmap + \
                                int(len(''.join(bitmap_list)) / 2))

        # dump the bitmap
        for i in range(0, self.nbitmap):
            f.write('# Bitmap: Block=%d, Length=%d\n' %
                    (block_list[i], maplen_list[i]))
            f.write('%02x %02x %s\n' %
                    (block_list[i], maplen_list[i], bitmap_list[i]))

class NSEC(NSECBASE):
    rdlen = None                # auto-calculate
    nextname = 'next.example.com'
    def dump_fixedpart(self, f, bitmap_totallen):
        name_wire = encode_name(self.nextname)
        if self.rdlen is None:
            # if rdlen needs to be calculated, it must be based on the bitmap
            # length, because the configured maplen can be fake.
            self.rdlen = int(len(name_wire) / 2) + bitmap_totallen
        f.write('\n# NSEC RDATA (RDLEN=%d)\n' % self.rdlen)
        f.write('%04x\n' % self.rdlen);
        f.write('# Next Name=%s (%d bytes)\n' % (self.nextname,
                                                 int(len(name_wire) / 2)))
        f.write('%s\n' % name_wire)

class NSEC3(NSECBASE):
    rdlen = None                # auto-calculate
    hashalg = 1                 # SHA-1
    optout = False              # opt-out flag
    mbz = 0                     # other flag fields (none defined yet)
    iterations = 1
    saltlen = 5
    salt = 's' * saltlen
    hashlen = 20
    hash = 'h' * hashlen
    def dump_fixedpart(self, f, bitmap_totallen):
        if self.rdlen is None:
            # if rdlen needs to be calculated, it must be based on the bitmap
            # length, because the configured maplen can be fake.
            self.rdlen = 4 + 1 + len(self.salt) + 1 + len(self.hash) \
                + bitmap_totallen
        f.write('\n# NSEC3 RDATA (RDLEN=%d)\n' % self.rdlen)
        f.write('%04x\n' % self.rdlen)
        optout_val = 1 if self.optout else 0
        f.write('# Hash Alg=%s, Opt-Out=%d, Other Flags=%0x, Iterations=%d\n' %
                (code_totext(self.hashalg, rdict_nsec3_algorithm),
                 optout_val, self.mbz, self.iterations))
        f.write('%02x %02x %04x\n' %
                (self.hashalg, (self.mbz << 1) | optout_val, self.iterations))
        f.write("# Salt Len=%d, Salt='%s'\n" % (self.saltlen, self.salt))
        f.write('%02x%s%s\n' % (self.saltlen,
                                ' ' if len(self.salt) > 0 else '',
                                encode_string(self.salt)))
        f.write("# Hash Len=%d, Hash='%s'\n" % (self.hashlen, self.hash))
        f.write('%02x%s%s\n' % (self.hashlen,
                                ' ' if len(self.hash) > 0 else '',
                                encode_string(self.hash)))

class RRSIG:
    rdlen = -1                  # auto-calculate
    covered = 1                 # A
    algorithm = 5               # RSA-SHA1
    labels = -1                 # auto-calculate (#labels of signer)
    originalttl = 3600
    expiration = int(time.mktime(datetime.strptime('20100131120000',
                                                   dnssec_timefmt).timetuple()))
    inception = int(time.mktime(datetime.strptime('20100101120000',
                                                  dnssec_timefmt).timetuple()))
    tag = 0x1035
    signer = 'example.com'
    signature = 0x123456789abcdef123456789abcdef
    def dump(self, f):
        name_wire = encode_name(self.signer)
        sig_wire = '%x' % self.signature 
        rdlen = self.rdlen
        if rdlen < 0:
            rdlen = int(18 + len(name_wire) / 2 + len(str(sig_wire)) / 2)
        labels = self.labels
        if labels < 0:
            labels = count_namelabels(self.signer)
        f.write('\n# RRSIG RDATA (RDLEN=%d)\n' % rdlen)
        f.write('%04x\n' % rdlen);
        f.write('# Covered=%s Algorithm=%s Labels=%d OrigTTL=%d\n' %
                (code_totext(self.covered, rdict_rrtype),
                 code_totext(self.algorithm, rdict_algorithm), labels,
                 self.originalttl))
        f.write('%04x %02x %02x %08x\n' % (self.covered, self.algorithm,
                                           labels, self.originalttl))
        f.write('# Expiration=%s, Inception=%s\n' %
                (str(self.expiration), str(self.inception)))
        f.write('%08x %08x\n' % (self.expiration, self.inception))
        f.write('# Tag=%d Signer=%s and Signature\n' % (self.tag, self.signer))
        f.write('%04x %s %s\n' % (self.tag, name_wire, sig_wire))

class TSIG(RR):
    rdlen = None                # auto-calculate
    algorithm = 'hmac-sha256'
    time_signed = 1286978795    # arbitrarily chosen default
    fudge = 300
    mac_size = None             # use a common value for the algorithm
    mac = None                  # use 'x' * mac_size
    original_id = 2845          # arbitrarily chosen default
    error = 0
    other_len = None         # 6 if error is BADTIME; otherwise 0
    other_data = None        # use time_signed + fudge + 1 for BADTIME
    dict_macsize = { 'hmac-md5' : 16, 'hmac-sha1' : 20, 'hmac-sha256' : 32 }

    # TSIG has some special defaults
    def __init__(self):
        super().__init__()
        self.rr_class = 'ANY'
        self.rr_ttl = 0

    def dump(self, f):
        if str(self.algorithm) == 'hmac-md5':
            name_wire = encode_name('hmac-md5.sig-alg.reg.int')
        else:
            name_wire = encode_name(self.algorithm)
        mac_size = self.mac_size
        if mac_size is None:
            if self.algorithm in self.dict_macsize.keys():
                mac_size = self.dict_macsize[self.algorithm]
            else:
                raise RuntimeError('TSIG Mac Size cannot be determined')
        mac = encode_string('x' * mac_size) if self.mac is None else \
            encode_string(self.mac, mac_size)
        other_len = self.other_len
        if other_len is None:
            # 18 = BADTIME
            other_len = 6 if self.error == 18 else 0
        other_data = self.other_data
        if other_data is None:
            other_data = '%012x' % (self.time_signed + self.fudge + 1) \
                if self.error == 18 else ''
        else:
            other_data = encode_string(self.other_data, other_len)
        if self.rdlen is None:
            self.rdlen = int(len(name_wire) / 2 + 16 + len(mac) / 2 + \
                                 len(other_data) / 2)
        self.dump_header(f, self.rdlen)
        f.write('# Algorithm=%s Time-Signed=%d Fudge=%d\n' %
                (self.algorithm, self.time_signed, self.fudge))
        f.write('%s %012x %04x\n' % (name_wire, self.time_signed, self.fudge))
        f.write('# MAC Size=%d MAC=(see hex)\n' % mac_size)
        f.write('%04x%s\n' % (mac_size, ' ' + mac if len(mac) > 0 else ''))
        f.write('# Original-ID=%d Error=%d\n' % (self.original_id, self.error))
        f.write('%04x %04x\n' %  (self.original_id, self.error))
        f.write('# Other-Len=%d Other-Data=(see hex)\n' % other_len)
        f.write('%04x%s\n' % (other_len,
                              ' ' + other_data if len(other_data) > 0 else ''))

def get_config_param(section):
    config_param = {'name' : (Name, {}),
                    'header' : (DNSHeader, header_xtables),
                    'question' : (DNSQuestion, question_xtables),
                    'edns' : (EDNS, {}), 'a' : (A, {}), 'ns' : (NS, {}),
                    'soa' : (SOA, {}), 'txt' : (TXT, {}),
                    'rp' : (RP, {}), 'rrsig' : (RRSIG, {}),
                    'nsec' : (NSEC, {}), 'nsec3' : (NSEC3, {}),
                    'tsig' : (TSIG, {}) }
    s = section
    m = re.match('^([^:]+)/\d+$', section)
    if m:
        s = m.group(1)
    return config_param[s]

usage = '''usage: %prog [options] input_file'''

if __name__ == "__main__":
    parser = OptionParser(usage=usage)
    parser.add_option('-o', '--output', action='store', dest='output',
                      default=None, metavar='FILE',
                      help='output file name [default: prefix of input_file]')
    (options, args) = parser.parse_args()

    if len(args) == 0:
        parser.error('input file is missing')
    configfile = args[0]

    outputfile = options.output
    if not outputfile:
        m = re.match('(.*)\.[^.]+$', configfile)
        if m:
            outputfile = m.group(1)
        else:
            raise ValueError('output file is not specified and input file is not in the form of "output_file.suffix"')

    config = configparser.SafeConfigParser()
    config.read(configfile)

    output = open(outputfile, 'w')

    print_header(output, configfile)

    # First try the 'custom' mode; if it fails assume the standard mode.
    try:
        sections = config.get('custom', 'sections').split(':')
    except configparser.NoSectionError:
        sections = ['header', 'question', 'edns']

    for s in sections:
        section_param = get_config_param(s)
        (obj, xtables) = (section_param[0](), section_param[1])
        if get_config(config, s, obj, xtables):
            obj.dump(output)

    output.close()