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Diffstat (limited to 'dns/masterfile.py')
| -rw-r--r-- | dns/masterfile.py | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/dns/masterfile.py b/dns/masterfile.py new file mode 100644 index 0000000..30553b5 --- /dev/null +++ b/dns/masterfile.py @@ -0,0 +1,404 @@ +# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license + +# Copyright (C) 2003-2007, 2009-2011 Nominum, Inc. +# +# Permission to use, copy, modify, and distribute this software and its +# documentation 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 NOMINUM DISCLAIMS ALL WARRANTIES +# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM 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. + +"""DNS Zones.""" + +import re +import sys + +import dns.exception +import dns.name +import dns.node +import dns.rdataclass +import dns.rdatatype +import dns.rdata +import dns.rdtypes.ANY.SOA +import dns.rrset +import dns.tokenizer +import dns.transaction +import dns.ttl +import dns.grange + + +class UnknownOrigin(dns.exception.DNSException): + """Unknown origin""" + + +class Reader: + + """Read a DNS master file into a transaction.""" + + def __init__(self, tok, origin, rdclass, relativize, txn, + allow_include=False): + if isinstance(origin, str): + origin = dns.name.from_text(origin) + self.tok = tok + self.current_origin = origin + self.relativize = relativize + self.last_ttl = 0 + self.last_ttl_known = False + self.default_ttl = 0 + self.default_ttl_known = False + self.last_name = self.current_origin + self.zone_origin = origin + self.zone_rdclass = rdclass + self.txn = txn + self.saved_state = [] + self.current_file = None + self.allow_include = allow_include + + def _eat_line(self): + while 1: + token = self.tok.get() + if token.is_eol_or_eof(): + break + + def _rr_line(self): + """Process one line from a DNS master file.""" + # Name + if self.current_origin is None: + raise UnknownOrigin + token = self.tok.get(want_leading=True) + if not token.is_whitespace(): + self.last_name = self.tok.as_name(token, self.current_origin) + else: + token = self.tok.get() + if token.is_eol_or_eof(): + # treat leading WS followed by EOL/EOF as if they were EOL/EOF. + return + self.tok.unget(token) + name = self.last_name + if not name.is_subdomain(self.zone_origin): + self._eat_line() + return + if self.relativize: + name = name.relativize(self.zone_origin) + token = self.tok.get() + if not token.is_identifier(): + raise dns.exception.SyntaxError + + # TTL + ttl = None + try: + ttl = dns.ttl.from_text(token.value) + self.last_ttl = ttl + self.last_ttl_known = True + token = self.tok.get() + if not token.is_identifier(): + raise dns.exception.SyntaxError + except dns.ttl.BadTTL: + if self.default_ttl_known: + ttl = self.default_ttl + elif self.last_ttl_known: + ttl = self.last_ttl + + # Class + try: + rdclass = dns.rdataclass.from_text(token.value) + token = self.tok.get() + if not token.is_identifier(): + raise dns.exception.SyntaxError + except dns.exception.SyntaxError: + raise + except Exception: + rdclass = self.zone_rdclass + if rdclass != self.zone_rdclass: + raise dns.exception.SyntaxError("RR class is not zone's class") + # Type + try: + rdtype = dns.rdatatype.from_text(token.value) + except Exception: + raise dns.exception.SyntaxError( + "unknown rdatatype '%s'" % token.value) + try: + rd = dns.rdata.from_text(rdclass, rdtype, self.tok, + self.current_origin, self.relativize, + self.zone_origin) + except dns.exception.SyntaxError: + # Catch and reraise. + raise + except Exception: + # All exceptions that occur in the processing of rdata + # are treated as syntax errors. This is not strictly + # correct, but it is correct almost all of the time. + # We convert them to syntax errors so that we can emit + # helpful filename:line info. + (ty, va) = sys.exc_info()[:2] + raise dns.exception.SyntaxError( + "caught exception {}: {}".format(str(ty), str(va))) + + if not self.default_ttl_known and rdtype == dns.rdatatype.SOA: + # The pre-RFC2308 and pre-BIND9 behavior inherits the zone default + # TTL from the SOA minttl if no $TTL statement is present before the + # SOA is parsed. + self.default_ttl = rd.minimum + self.default_ttl_known = True + if ttl is None: + # if we didn't have a TTL on the SOA, set it! + ttl = rd.minimum + + # TTL check. We had to wait until now to do this as the SOA RR's + # own TTL can be inferred from its minimum. + if ttl is None: + raise dns.exception.SyntaxError("Missing default TTL value") + + self.txn.add(name, ttl, rd) + + def _parse_modify(self, side): + # Here we catch everything in '{' '}' in a group so we can replace it + # with ''. + is_generate1 = re.compile(r"^.*\$({(\+|-?)(\d+),(\d+),(.)}).*$") + is_generate2 = re.compile(r"^.*\$({(\+|-?)(\d+)}).*$") + is_generate3 = re.compile(r"^.*\$({(\+|-?)(\d+),(\d+)}).*$") + # Sometimes there are modifiers in the hostname. These come after + # the dollar sign. They are in the form: ${offset[,width[,base]]}. + # Make names + g1 = is_generate1.match(side) + if g1: + mod, sign, offset, width, base = g1.groups() + if sign == '': + sign = '+' + g2 = is_generate2.match(side) + if g2: + mod, sign, offset = g2.groups() + if sign == '': + sign = '+' + width = 0 + base = 'd' + g3 = is_generate3.match(side) + if g3: + mod, sign, offset, width = g3.groups() + if sign == '': + sign = '+' + base = 'd' + + if not (g1 or g2 or g3): + mod = '' + sign = '+' + offset = 0 + width = 0 + base = 'd' + + if base != 'd': + raise NotImplementedError() + + return mod, sign, offset, width, base + + def _generate_line(self): + # range lhs [ttl] [class] type rhs [ comment ] + """Process one line containing the GENERATE statement from a DNS + master file.""" + if self.current_origin is None: + raise UnknownOrigin + + token = self.tok.get() + # Range (required) + try: + start, stop, step = dns.grange.from_text(token.value) + token = self.tok.get() + if not token.is_identifier(): + raise dns.exception.SyntaxError + except Exception: + raise dns.exception.SyntaxError + + # lhs (required) + try: + lhs = token.value + token = self.tok.get() + if not token.is_identifier(): + raise dns.exception.SyntaxError + except Exception: + raise dns.exception.SyntaxError + + # TTL + try: + ttl = dns.ttl.from_text(token.value) + self.last_ttl = ttl + self.last_ttl_known = True + token = self.tok.get() + if not token.is_identifier(): + raise dns.exception.SyntaxError + except dns.ttl.BadTTL: + if not (self.last_ttl_known or self.default_ttl_known): + raise dns.exception.SyntaxError("Missing default TTL value") + if self.default_ttl_known: + ttl = self.default_ttl + elif self.last_ttl_known: + ttl = self.last_ttl + # Class + try: + rdclass = dns.rdataclass.from_text(token.value) + token = self.tok.get() + if not token.is_identifier(): + raise dns.exception.SyntaxError + except dns.exception.SyntaxError: + raise dns.exception.SyntaxError + except Exception: + rdclass = self.zone_rdclass + if rdclass != self.zone_rdclass: + raise dns.exception.SyntaxError("RR class is not zone's class") + # Type + try: + rdtype = dns.rdatatype.from_text(token.value) + token = self.tok.get() + if not token.is_identifier(): + raise dns.exception.SyntaxError + except Exception: + raise dns.exception.SyntaxError("unknown rdatatype '%s'" % + token.value) + + # rhs (required) + rhs = token.value + + # The code currently only supports base 'd', so the last value + # in the tuple _parse_modify returns is ignored + lmod, lsign, loffset, lwidth, _ = self._parse_modify(lhs) + rmod, rsign, roffset, rwidth, _ = self._parse_modify(rhs) + for i in range(start, stop + 1, step): + # +1 because bind is inclusive and python is exclusive + + if lsign == '+': + lindex = i + int(loffset) + elif lsign == '-': + lindex = i - int(loffset) + + if rsign == '-': + rindex = i - int(roffset) + elif rsign == '+': + rindex = i + int(roffset) + + lzfindex = str(lindex).zfill(int(lwidth)) + rzfindex = str(rindex).zfill(int(rwidth)) + + name = lhs.replace('$%s' % (lmod), lzfindex) + rdata = rhs.replace('$%s' % (rmod), rzfindex) + + self.last_name = dns.name.from_text(name, self.current_origin, + self.tok.idna_codec) + name = self.last_name + if not name.is_subdomain(self.zone_origin): + self._eat_line() + return + if self.relativize: + name = name.relativize(self.zone_origin) + + try: + rd = dns.rdata.from_text(rdclass, rdtype, rdata, + self.current_origin, self.relativize, + self.zone_origin) + except dns.exception.SyntaxError: + # Catch and reraise. + raise + except Exception: + # All exceptions that occur in the processing of rdata + # are treated as syntax errors. This is not strictly + # correct, but it is correct almost all of the time. + # We convert them to syntax errors so that we can emit + # helpful filename:line info. + (ty, va) = sys.exc_info()[:2] + raise dns.exception.SyntaxError("caught exception %s: %s" % + (str(ty), str(va))) + + self.txn.add(name, ttl, rd) + + def read(self): + """Read a DNS master file and build a zone object. + + @raises dns.zone.NoSOA: No SOA RR was found at the zone origin + @raises dns.zone.NoNS: No NS RRset was found at the zone origin + """ + + try: + while 1: + token = self.tok.get(True, True) + if token.is_eof(): + if self.current_file is not None: + self.current_file.close() + if len(self.saved_state) > 0: + (self.tok, + self.current_origin, + self.last_name, + self.current_file, + self.last_ttl, + self.last_ttl_known, + self.default_ttl, + self.default_ttl_known) = self.saved_state.pop(-1) + continue + break + elif token.is_eol(): + continue + elif token.is_comment(): + self.tok.get_eol() + continue + elif token.value[0] == '$': + c = token.value.upper() + if c == '$TTL': + token = self.tok.get() + if not token.is_identifier(): + raise dns.exception.SyntaxError("bad $TTL") + self.default_ttl = dns.ttl.from_text(token.value) + self.default_ttl_known = True + self.tok.get_eol() + elif c == '$ORIGIN': + self.current_origin = self.tok.get_name() + self.tok.get_eol() + if self.zone_origin is None: + self.zone_origin = self.current_origin + self.txn._set_origin(self.current_origin) + elif c == '$INCLUDE' and self.allow_include: + token = self.tok.get() + filename = token.value + token = self.tok.get() + if token.is_identifier(): + new_origin =\ + dns.name.from_text(token.value, + self.current_origin, + self.tok.idna_codec) + self.tok.get_eol() + elif not token.is_eol_or_eof(): + raise dns.exception.SyntaxError( + "bad origin in $INCLUDE") + else: + new_origin = self.current_origin + self.saved_state.append((self.tok, + self.current_origin, + self.last_name, + self.current_file, + self.last_ttl, + self.last_ttl_known, + self.default_ttl, + self.default_ttl_known)) + self.current_file = open(filename, 'r') + self.tok = dns.tokenizer.Tokenizer(self.current_file, + filename) + self.current_origin = new_origin + elif c == '$GENERATE': + self._generate_line() + else: + raise dns.exception.SyntaxError( + "Unknown master file directive '" + c + "'") + continue + self.tok.unget(token) + self._rr_line() + except dns.exception.SyntaxError as detail: + (filename, line_number) = self.tok.where() + if detail is None: + detail = "syntax error" + ex = dns.exception.SyntaxError( + "%s:%d: %s" % (filename, line_number, detail)) + tb = sys.exc_info()[2] + raise ex.with_traceback(tb) from None |