Current File : //lib/python3/dist-packages/dns/zonefile.py
# 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
from typing import Any, Iterable, List, Optional, Set, Tuple, Union
import dns.exception
import dns.grange
import dns.name
import dns.node
import dns.rdata
import dns.rdataclass
import dns.rdatatype
import dns.rdtypes.ANY.SOA
import dns.rrset
import dns.tokenizer
import dns.transaction
import dns.ttl
class UnknownOrigin(dns.exception.DNSException):
"""Unknown origin"""
class CNAMEAndOtherData(dns.exception.DNSException):
"""A node has a CNAME and other data"""
def _check_cname_and_other_data(txn, name, rdataset):
rdataset_kind = dns.node.NodeKind.classify_rdataset(rdataset)
node = txn.get_node(name)
if node is None:
# empty nodes are neutral.
return
node_kind = node.classify()
if (
node_kind == dns.node.NodeKind.CNAME
and rdataset_kind == dns.node.NodeKind.REGULAR
):
raise CNAMEAndOtherData("rdataset type is not compatible with a CNAME node")
elif (
node_kind == dns.node.NodeKind.REGULAR
and rdataset_kind == dns.node.NodeKind.CNAME
):
raise CNAMEAndOtherData(
"CNAME rdataset is not compatible with a regular data node"
)
# Otherwise at least one of the node and the rdataset is neutral, so
# adding the rdataset is ok
SavedStateType = Tuple[
dns.tokenizer.Tokenizer,
Optional[dns.name.Name], # current_origin
Optional[dns.name.Name], # last_name
Optional[Any], # current_file
int, # last_ttl
bool, # last_ttl_known
int, # default_ttl
bool,
] # default_ttl_known
def _upper_dollarize(s):
s = s.upper()
if not s.startswith("$"):
s = "$" + s
return s
class Reader:
"""Read a DNS zone file into a transaction."""
def __init__(
self,
tok: dns.tokenizer.Tokenizer,
rdclass: dns.rdataclass.RdataClass,
txn: dns.transaction.Transaction,
allow_include: bool = False,
allow_directives: Union[bool, Iterable[str]] = True,
force_name: Optional[dns.name.Name] = None,
force_ttl: Optional[int] = None,
force_rdclass: Optional[dns.rdataclass.RdataClass] = None,
force_rdtype: Optional[dns.rdatatype.RdataType] = None,
default_ttl: Optional[int] = None,
):
self.tok = tok
(self.zone_origin, self.relativize, _) = txn.manager.origin_information()
self.current_origin = self.zone_origin
self.last_ttl = 0
self.last_ttl_known = False
if force_ttl is not None:
default_ttl = force_ttl
if default_ttl is None:
self.default_ttl = 0
self.default_ttl_known = False
else:
self.default_ttl = default_ttl
self.default_ttl_known = True
self.last_name = self.current_origin
self.zone_rdclass = rdclass
self.txn = txn
self.saved_state: List[SavedStateType] = []
self.current_file: Optional[Any] = None
self.allowed_directives: Set[str]
if allow_directives is True:
self.allowed_directives = {"$GENERATE", "$ORIGIN", "$TTL"}
if allow_include:
self.allowed_directives.add("$INCLUDE")
elif allow_directives is False:
# allow_include was ignored in earlier releases if allow_directives was
# False, so we continue that.
self.allowed_directives = set()
else:
# Note that if directives are explicitly specified, then allow_include
# is ignored.
self.allowed_directives = set(_upper_dollarize(d) for d in allow_directives)
self.force_name = force_name
self.force_ttl = force_ttl
self.force_rdclass = force_rdclass
self.force_rdtype = force_rdtype
self.txn.check_put_rdataset(_check_cname_and_other_data)
def _eat_line(self):
while 1:
token = self.tok.get()
if token.is_eol_or_eof():
break
def _get_identifier(self):
token = self.tok.get()
if not token.is_identifier():
raise dns.exception.SyntaxError
return token
def _rr_line(self):
"""Process one line from a DNS zone file."""
token = None
# Name
if self.force_name is not None:
name = self.force_name
else:
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)
# TTL
if self.force_ttl is not None:
ttl = self.force_ttl
self.last_ttl = ttl
self.last_ttl_known = True
else:
token = self._get_identifier()
ttl = None
try:
ttl = dns.ttl.from_text(token.value)
self.last_ttl = ttl
self.last_ttl_known = True
token = None
except dns.ttl.BadTTL:
self.tok.unget(token)
# Class
if self.force_rdclass is not None:
rdclass = self.force_rdclass
else:
token = self._get_identifier()
try:
rdclass = dns.rdataclass.from_text(token.value)
except dns.exception.SyntaxError:
raise
except Exception:
rdclass = self.zone_rdclass
self.tok.unget(token)
if rdclass != self.zone_rdclass:
raise dns.exception.SyntaxError("RR class is not zone's class")
if ttl is None:
# support for <class> <ttl> <type> syntax
token = self._get_identifier()
ttl = None
try:
ttl = dns.ttl.from_text(token.value)
self.last_ttl = ttl
self.last_ttl_known = True
token = None
except dns.ttl.BadTTL:
if self.default_ttl_known:
ttl = self.default_ttl
elif self.last_ttl_known:
ttl = self.last_ttl
self.tok.unget(token)
# Type
if self.force_rdtype is not None:
rdtype = self.force_rdtype
else:
token = self._get_identifier()
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 $TTL statement is present before the
# SOA is parsed.
self.default_ttl = rd.minimum
self.default_ttl_known = True
if ttl is None:
# if we didn't have a TTL on the SOA, set it!
ttl = rd.minimum
# TTL check. We had to wait until now to do this as the SOA RR's
# own TTL can be inferred from its minimum.
if ttl is None:
raise dns.exception.SyntaxError("Missing default TTL value")
self.txn.add(name, ttl, rd)
def _parse_modify(self, side: str) -> Tuple[str, str, int, int, str]:
# Here we catch everything in '{' '}' in a group so we can replace it
# with ''.
is_generate1 = re.compile(r"^.*\$({(\+|-?)(\d+),(\d+),(.)}).*$")
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"
offset = int(offset)
width = int(width)
if sign not in ["+", "-"]:
raise dns.exception.SyntaxError("invalid offset sign %s" % sign)
if base not in ["d", "o", "x", "X", "n", "N"]:
raise dns.exception.SyntaxError("invalid type %s" % base)
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
zone 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
def _calculate_index(counter: int, offset_sign: str, offset: int) -> int:
"""Calculate the index from the counter and offset."""
if offset_sign == "-":
offset *= -1
return counter + offset
def _format_index(index: int, base: str, width: int) -> str:
"""Format the index with the given base, and zero-fill it
to the given width."""
if base in ["d", "o", "x", "X"]:
return format(index, base).zfill(width)
# base can only be n or N here
hexa = _format_index(index, "x", width)
nibbles = ".".join(hexa[::-1])[:width]
if base == "N":
nibbles = nibbles.upper()
return nibbles
lmod, lsign, loffset, lwidth, lbase = self._parse_modify(lhs)
rmod, rsign, roffset, rwidth, rbase = self._parse_modify(rhs)
for i in range(start, stop + 1, step):
# +1 because bind is inclusive and python is exclusive
lindex = _calculate_index(i, lsign, loffset)
rindex = _calculate_index(i, rsign, roffset)
lzfindex = _format_index(lindex, lbase, lwidth)
rzfindex = _format_index(rindex, rbase, rwidth)
name = lhs.replace("$%s" % (lmod), lzfindex)
rdata = rhs.replace("$%s" % (rmod), rzfindex)
self.last_name = dns.name.from_text(
name, self.current_origin, self.tok.idna_codec
)
name = self.last_name
if not name.is_subdomain(self.zone_origin):
self._eat_line()
return
if self.relativize:
name = name.relativize(self.zone_origin)
try:
rd = dns.rdata.from_text(
rdclass,
rdtype,
rdata,
self.current_origin,
self.relativize,
self.zone_origin,
)
except dns.exception.SyntaxError:
# Catch and reraise.
raise
except Exception:
# All exceptions that occur in the processing of rdata
# are treated as syntax errors. This is not strictly
# correct, but it is correct almost all of the time.
# We convert them to syntax errors so that we can emit
# helpful filename:line info.
(ty, va) = sys.exc_info()[:2]
raise dns.exception.SyntaxError(
"caught exception %s: %s" % (str(ty), str(va))
)
self.txn.add(name, ttl, rd)
def read(self) -> None:
"""Read a DNS zone file and build a zone object.
@raises dns.zone.NoSOA: No SOA RR was found at the zone origin
@raises dns.zone.NoNS: No NS RRset was found at the zone origin
"""
try:
while 1:
token = self.tok.get(True, True)
if token.is_eof():
if self.current_file is not None:
self.current_file.close()
if len(self.saved_state) > 0:
(
self.tok,
self.current_origin,
self.last_name,
self.current_file,
self.last_ttl,
self.last_ttl_known,
self.default_ttl,
self.default_ttl_known,
) = self.saved_state.pop(-1)
continue
break
elif token.is_eol():
continue
elif token.is_comment():
self.tok.get_eol()
continue
elif token.value[0] == "$" and len(self.allowed_directives) > 0:
# Note that we only run directive processing code if at least
# one directive is allowed in order to be backwards compatible
c = token.value.upper()
if c not in self.allowed_directives:
raise dns.exception.SyntaxError(
f"zone file directive '{c}' is not allowed"
)
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":
token = self.tok.get()
filename = token.value
token = self.tok.get()
new_origin: Optional[dns.name.Name]
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(
f"Unknown zone 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
class RRsetsReaderTransaction(dns.transaction.Transaction):
def __init__(self, manager, replacement, read_only):
assert not read_only
super().__init__(manager, replacement, read_only)
self.rdatasets = {}
def _get_rdataset(self, name, rdtype, covers):
return self.rdatasets.get((name, rdtype, covers))
def _get_node(self, name):
rdatasets = []
for (rdataset_name, _, _), rdataset in self.rdatasets.items():
if name == rdataset_name:
rdatasets.append(rdataset)
if len(rdatasets) == 0:
return None
node = dns.node.Node()
node.rdatasets = rdatasets
return node
def _put_rdataset(self, name, rdataset):
self.rdatasets[(name, rdataset.rdtype, rdataset.covers)] = rdataset
def _delete_name(self, name):
# First remove any changes involving the name
remove = []
for key in self.rdatasets:
if key[0] == name:
remove.append(key)
if len(remove) > 0:
for key in remove:
del self.rdatasets[key]
def _delete_rdataset(self, name, rdtype, covers):
try:
del self.rdatasets[(name, rdtype, covers)]
except KeyError:
pass
def _name_exists(self, name):
for n, _, _ in self.rdatasets:
if n == name:
return True
return False
def _changed(self):
return len(self.rdatasets) > 0
def _end_transaction(self, commit):
if commit and self._changed():
rrsets = []
for (name, _, _), rdataset in self.rdatasets.items():
rrset = dns.rrset.RRset(
name, rdataset.rdclass, rdataset.rdtype, rdataset.covers
)
rrset.update(rdataset)
rrsets.append(rrset)
self.manager.set_rrsets(rrsets)
def _set_origin(self, origin):
pass
def _iterate_rdatasets(self):
raise NotImplementedError # pragma: no cover
def _iterate_names(self):
raise NotImplementedError # pragma: no cover
class RRSetsReaderManager(dns.transaction.TransactionManager):
def __init__(
self, origin=dns.name.root, relativize=False, rdclass=dns.rdataclass.IN
):
self.origin = origin
self.relativize = relativize
self.rdclass = rdclass
self.rrsets = []
def reader(self): # pragma: no cover
raise NotImplementedError
def writer(self, replacement=False):
assert replacement is True
return RRsetsReaderTransaction(self, True, False)
def get_class(self):
return self.rdclass
def origin_information(self):
if self.relativize:
effective = dns.name.empty
else:
effective = self.origin
return (self.origin, self.relativize, effective)
def set_rrsets(self, rrsets):
self.rrsets = rrsets
def read_rrsets(
text: Any,
name: Optional[Union[dns.name.Name, str]] = None,
ttl: Optional[int] = None,
rdclass: Optional[Union[dns.rdataclass.RdataClass, str]] = dns.rdataclass.IN,
default_rdclass: Union[dns.rdataclass.RdataClass, str] = dns.rdataclass.IN,
rdtype: Optional[Union[dns.rdatatype.RdataType, str]] = None,
default_ttl: Optional[Union[int, str]] = None,
idna_codec: Optional[dns.name.IDNACodec] = None,
origin: Optional[Union[dns.name.Name, str]] = dns.name.root,
relativize: bool = False,
) -> List[dns.rrset.RRset]:
"""Read one or more rrsets from the specified text, possibly subject
to restrictions.
*text*, a file object or a string, is the input to process.
*name*, a string, ``dns.name.Name``, or ``None``, is the owner name of
the rrset. If not ``None``, then the owner name is "forced", and the
input must not specify an owner name. If ``None``, then any owner names
are allowed and must be present in the input.
*ttl*, an ``int``, string, or None. If not ``None``, the the TTL is
forced to be the specified value and the input must not specify a TTL.
If ``None``, then a TTL may be specified in the input. If it is not
specified, then the *default_ttl* will be used.
*rdclass*, a ``dns.rdataclass.RdataClass``, string, or ``None``. If
not ``None``, then the class is forced to the specified value, and the
input must not specify a class. If ``None``, then the input may specify
a class that matches *default_rdclass*. Note that it is not possible to
return rrsets with differing classes; specifying ``None`` for the class
simply allows the user to optionally type a class as that may be convenient
when cutting and pasting.
*default_rdclass*, a ``dns.rdataclass.RdataClass`` or string. The class
of the returned rrsets.
*rdtype*, a ``dns.rdatatype.RdataType``, string, or ``None``. If not
``None``, then the type is forced to the specified value, and the
input must not specify a type. If ``None``, then a type must be present
for each RR.
*default_ttl*, an ``int``, string, or ``None``. If not ``None``, then if
the TTL is not forced and is not specified, then this value will be used.
if ``None``, then if the TTL is not forced an error will occur if the TTL
is not specified.
*idna_codec*, a ``dns.name.IDNACodec``, specifies the IDNA
encoder/decoder. If ``None``, the default IDNA 2003 encoder/decoder
is used. Note that codecs only apply to the owner name; dnspython does
not do IDNA for names in rdata, as there is no IDNA zonefile format.
*origin*, a string, ``dns.name.Name``, or ``None``, is the origin for any
relative names in the input, and also the origin to relativize to if
*relativize* is ``True``.
*relativize*, a bool. If ``True``, names are relativized to the *origin*;
if ``False`` then any relative names in the input are made absolute by
appending the *origin*.
"""
if isinstance(origin, str):
origin = dns.name.from_text(origin, dns.name.root, idna_codec)
if isinstance(name, str):
name = dns.name.from_text(name, origin, idna_codec)
if isinstance(ttl, str):
ttl = dns.ttl.from_text(ttl)
if isinstance(default_ttl, str):
default_ttl = dns.ttl.from_text(default_ttl)
if rdclass is not None:
rdclass = dns.rdataclass.RdataClass.make(rdclass)
else:
rdclass = None
default_rdclass = dns.rdataclass.RdataClass.make(default_rdclass)
if rdtype is not None:
rdtype = dns.rdatatype.RdataType.make(rdtype)
else:
rdtype = None
manager = RRSetsReaderManager(origin, relativize, default_rdclass)
with manager.writer(True) as txn:
tok = dns.tokenizer.Tokenizer(text, "<input>", idna_codec=idna_codec)
reader = Reader(
tok,
default_rdclass,
txn,
allow_directives=False,
force_name=name,
force_ttl=ttl,
force_rdclass=rdclass,
force_rdtype=rdtype,
default_ttl=default_ttl,
)
reader.read()
return manager.rrsets
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