Current File : //proc/self/root/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
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 zone file into a transaction."""
def __init__(self, tok, rdclass, txn, allow_include=False):
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
self.default_ttl = 0
self.default_ttl_known = False
self.last_name = self.current_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 zone 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
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
# 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('$%s' % (rmod), rzfindex)
self.last_name = dns.name.from_text(name, self.current_origin,
self.tok.idna_codec)
name = self.last_name
if not name.is_subdomain(self.zone_origin):
self._eat_line()
return
if self.relativize:
name = name.relativize(self.zone_origin)
try:
rd = dns.rdata.from_text(rdclass, rdtype, rdata,
self.current_origin, self.relativize,
self.zone_origin)
except dns.exception.SyntaxError:
# Catch and reraise.
raise
except Exception:
# All exceptions that occur in the processing of rdata
# are treated as syntax errors. This is not strictly
# correct, but it is correct almost all of the time.
# We convert them to syntax errors so that we can emit
# helpful filename:line info.
(ty, va) = sys.exc_info()[:2]
raise dns.exception.SyntaxError("caught exception %s: %s" %
(str(ty), str(va)))
self.txn.add(name, ttl, rd)
def read(self):
"""Read a DNS zone file and build a zone object.
@raises dns.zone.NoSOA: No SOA RR was found at the zone origin
@raises dns.zone.NoNS: No NS RRset was found at the zone origin
"""
try:
while 1:
token = self.tok.get(True, True)
if token.is_eof():
if self.current_file is not None:
self.current_file.close()
if len(self.saved_state) > 0:
(self.tok,
self.current_origin,
self.last_name,
self.current_file,
self.last_ttl,
self.last_ttl_known,
self.default_ttl,
self.default_ttl_known) = self.saved_state.pop(-1)
continue
break
elif token.is_eol():
continue
elif token.is_comment():
self.tok.get_eol()
continue
elif token.value[0] == '$':
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 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
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