You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
683 lines
23 KiB
683 lines
23 KiB
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
|
|
|
|
# Copyright (C) 2003-2017 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.
|
|
|
|
"""Talk to a DNS server."""
|
|
|
|
from __future__ import generators
|
|
|
|
import errno
|
|
import select
|
|
import socket
|
|
import struct
|
|
import sys
|
|
import time
|
|
|
|
import dns.exception
|
|
import dns.inet
|
|
import dns.name
|
|
import dns.message
|
|
import dns.rcode
|
|
import dns.rdataclass
|
|
import dns.rdatatype
|
|
from ._compat import long, string_types, PY3
|
|
|
|
if PY3:
|
|
select_error = OSError
|
|
else:
|
|
select_error = select.error
|
|
|
|
# Function used to create a socket. Can be overridden if needed in special
|
|
# situations.
|
|
socket_factory = socket.socket
|
|
|
|
class UnexpectedSource(dns.exception.DNSException):
|
|
"""A DNS query response came from an unexpected address or port."""
|
|
|
|
|
|
class BadResponse(dns.exception.FormError):
|
|
"""A DNS query response does not respond to the question asked."""
|
|
|
|
|
|
class TransferError(dns.exception.DNSException):
|
|
"""A zone transfer response got a non-zero rcode."""
|
|
|
|
def __init__(self, rcode):
|
|
message = 'Zone transfer error: %s' % dns.rcode.to_text(rcode)
|
|
super(TransferError, self).__init__(message)
|
|
self.rcode = rcode
|
|
|
|
|
|
def _compute_expiration(timeout):
|
|
if timeout is None:
|
|
return None
|
|
else:
|
|
return time.time() + timeout
|
|
|
|
# This module can use either poll() or select() as the "polling backend".
|
|
#
|
|
# A backend function takes an fd, bools for readability, writablity, and
|
|
# error detection, and a timeout.
|
|
|
|
def _poll_for(fd, readable, writable, error, timeout):
|
|
"""Poll polling backend."""
|
|
|
|
event_mask = 0
|
|
if readable:
|
|
event_mask |= select.POLLIN
|
|
if writable:
|
|
event_mask |= select.POLLOUT
|
|
if error:
|
|
event_mask |= select.POLLERR
|
|
|
|
pollable = select.poll()
|
|
pollable.register(fd, event_mask)
|
|
|
|
if timeout:
|
|
event_list = pollable.poll(long(timeout * 1000))
|
|
else:
|
|
event_list = pollable.poll()
|
|
|
|
return bool(event_list)
|
|
|
|
|
|
def _select_for(fd, readable, writable, error, timeout):
|
|
"""Select polling backend."""
|
|
|
|
rset, wset, xset = [], [], []
|
|
|
|
if readable:
|
|
rset = [fd]
|
|
if writable:
|
|
wset = [fd]
|
|
if error:
|
|
xset = [fd]
|
|
|
|
if timeout is None:
|
|
(rcount, wcount, xcount) = select.select(rset, wset, xset)
|
|
else:
|
|
(rcount, wcount, xcount) = select.select(rset, wset, xset, timeout)
|
|
|
|
return bool((rcount or wcount or xcount))
|
|
|
|
|
|
def _wait_for(fd, readable, writable, error, expiration):
|
|
# Use the selected polling backend to wait for any of the specified
|
|
# events. An "expiration" absolute time is converted into a relative
|
|
# timeout.
|
|
|
|
done = False
|
|
while not done:
|
|
if expiration is None:
|
|
timeout = None
|
|
else:
|
|
timeout = expiration - time.time()
|
|
if timeout <= 0.0:
|
|
raise dns.exception.Timeout
|
|
try:
|
|
if not _polling_backend(fd, readable, writable, error, timeout):
|
|
raise dns.exception.Timeout
|
|
except select_error as e:
|
|
if e.args[0] != errno.EINTR:
|
|
raise e
|
|
done = True
|
|
|
|
|
|
def _set_polling_backend(fn):
|
|
# Internal API. Do not use.
|
|
|
|
global _polling_backend
|
|
|
|
_polling_backend = fn
|
|
|
|
if hasattr(select, 'poll'):
|
|
# Prefer poll() on platforms that support it because it has no
|
|
# limits on the maximum value of a file descriptor (plus it will
|
|
# be more efficient for high values).
|
|
_polling_backend = _poll_for
|
|
else:
|
|
_polling_backend = _select_for
|
|
|
|
|
|
def _wait_for_readable(s, expiration):
|
|
_wait_for(s, True, False, True, expiration)
|
|
|
|
|
|
def _wait_for_writable(s, expiration):
|
|
_wait_for(s, False, True, True, expiration)
|
|
|
|
|
|
def _addresses_equal(af, a1, a2):
|
|
# Convert the first value of the tuple, which is a textual format
|
|
# address into binary form, so that we are not confused by different
|
|
# textual representations of the same address
|
|
try:
|
|
n1 = dns.inet.inet_pton(af, a1[0])
|
|
n2 = dns.inet.inet_pton(af, a2[0])
|
|
except dns.exception.SyntaxError:
|
|
return False
|
|
return n1 == n2 and a1[1:] == a2[1:]
|
|
|
|
|
|
def _destination_and_source(af, where, port, source, source_port):
|
|
# Apply defaults and compute destination and source tuples
|
|
# suitable for use in connect(), sendto(), or bind().
|
|
if af is None:
|
|
try:
|
|
af = dns.inet.af_for_address(where)
|
|
except Exception:
|
|
af = dns.inet.AF_INET
|
|
if af == dns.inet.AF_INET:
|
|
destination = (where, port)
|
|
if source is not None or source_port != 0:
|
|
if source is None:
|
|
source = '0.0.0.0'
|
|
source = (source, source_port)
|
|
elif af == dns.inet.AF_INET6:
|
|
destination = (where, port, 0, 0)
|
|
if source is not None or source_port != 0:
|
|
if source is None:
|
|
source = '::'
|
|
source = (source, source_port, 0, 0)
|
|
return (af, destination, source)
|
|
|
|
|
|
def send_udp(sock, what, destination, expiration=None):
|
|
"""Send a DNS message to the specified UDP socket.
|
|
|
|
*sock*, a ``socket``.
|
|
|
|
*what*, a ``binary`` or ``dns.message.Message``, the message to send.
|
|
|
|
*destination*, a destination tuple appropriate for the address family
|
|
of the socket, specifying where to send the query.
|
|
|
|
*expiration*, a ``float`` or ``None``, the absolute time at which
|
|
a timeout exception should be raised. If ``None``, no timeout will
|
|
occur.
|
|
|
|
Returns an ``(int, float)`` tuple of bytes sent and the sent time.
|
|
"""
|
|
|
|
if isinstance(what, dns.message.Message):
|
|
what = what.to_wire()
|
|
_wait_for_writable(sock, expiration)
|
|
sent_time = time.time()
|
|
n = sock.sendto(what, destination)
|
|
return (n, sent_time)
|
|
|
|
|
|
def receive_udp(sock, destination, expiration=None,
|
|
ignore_unexpected=False, one_rr_per_rrset=False,
|
|
keyring=None, request_mac=b'', ignore_trailing=False):
|
|
"""Read a DNS message from a UDP socket.
|
|
|
|
*sock*, a ``socket``.
|
|
|
|
*destination*, a destination tuple appropriate for the address family
|
|
of the socket, specifying where the associated query was sent.
|
|
|
|
*expiration*, a ``float`` or ``None``, the absolute time at which
|
|
a timeout exception should be raised. If ``None``, no timeout will
|
|
occur.
|
|
|
|
*ignore_unexpected*, a ``bool``. If ``True``, ignore responses from
|
|
unexpected sources.
|
|
|
|
*one_rr_per_rrset*, a ``bool``. If ``True``, put each RR into its own
|
|
RRset.
|
|
|
|
*keyring*, a ``dict``, the keyring to use for TSIG.
|
|
|
|
*request_mac*, a ``binary``, the MAC of the request (for TSIG).
|
|
|
|
*ignore_trailing*, a ``bool``. If ``True``, ignore trailing
|
|
junk at end of the received message.
|
|
|
|
Raises if the message is malformed, if network errors occur, of if
|
|
there is a timeout.
|
|
|
|
Returns a ``dns.message.Message`` object.
|
|
"""
|
|
|
|
wire = b''
|
|
while 1:
|
|
_wait_for_readable(sock, expiration)
|
|
(wire, from_address) = sock.recvfrom(65535)
|
|
if _addresses_equal(sock.family, from_address, destination) or \
|
|
(dns.inet.is_multicast(destination[0]) and
|
|
from_address[1:] == destination[1:]):
|
|
break
|
|
if not ignore_unexpected:
|
|
raise UnexpectedSource('got a response from '
|
|
'%s instead of %s' % (from_address,
|
|
destination))
|
|
received_time = time.time()
|
|
r = dns.message.from_wire(wire, keyring=keyring, request_mac=request_mac,
|
|
one_rr_per_rrset=one_rr_per_rrset,
|
|
ignore_trailing=ignore_trailing)
|
|
return (r, received_time)
|
|
|
|
def udp(q, where, timeout=None, port=53, af=None, source=None, source_port=0,
|
|
ignore_unexpected=False, one_rr_per_rrset=False, ignore_trailing=False):
|
|
"""Return the response obtained after sending a query via UDP.
|
|
|
|
*q*, a ``dns.message.Message``, the query to send
|
|
|
|
*where*, a ``text`` containing an IPv4 or IPv6 address, where
|
|
to send the message.
|
|
|
|
*timeout*, a ``float`` or ``None``, the number of seconds to wait before the
|
|
query times out. If ``None``, the default, wait forever.
|
|
|
|
*port*, an ``int``, the port send the message to. The default is 53.
|
|
|
|
*af*, an ``int``, the address family to use. The default is ``None``,
|
|
which causes the address family to use to be inferred from the form of
|
|
*where*. If the inference attempt fails, AF_INET is used. This
|
|
parameter is historical; you need never set it.
|
|
|
|
*source*, a ``text`` containing an IPv4 or IPv6 address, specifying
|
|
the source address. The default is the wildcard address.
|
|
|
|
*source_port*, an ``int``, the port from which to send the message.
|
|
The default is 0.
|
|
|
|
*ignore_unexpected*, a ``bool``. If ``True``, ignore responses from
|
|
unexpected sources.
|
|
|
|
*one_rr_per_rrset*, a ``bool``. If ``True``, put each RR into its own
|
|
RRset.
|
|
|
|
*ignore_trailing*, a ``bool``. If ``True``, ignore trailing
|
|
junk at end of the received message.
|
|
|
|
Returns a ``dns.message.Message``.
|
|
"""
|
|
|
|
wire = q.to_wire()
|
|
(af, destination, source) = _destination_and_source(af, where, port,
|
|
source, source_port)
|
|
s = socket_factory(af, socket.SOCK_DGRAM, 0)
|
|
received_time = None
|
|
sent_time = None
|
|
try:
|
|
expiration = _compute_expiration(timeout)
|
|
s.setblocking(0)
|
|
if source is not None:
|
|
s.bind(source)
|
|
(_, sent_time) = send_udp(s, wire, destination, expiration)
|
|
(r, received_time) = receive_udp(s, destination, expiration,
|
|
ignore_unexpected, one_rr_per_rrset,
|
|
q.keyring, q.mac, ignore_trailing)
|
|
finally:
|
|
if sent_time is None or received_time is None:
|
|
response_time = 0
|
|
else:
|
|
response_time = received_time - sent_time
|
|
s.close()
|
|
r.time = response_time
|
|
if not q.is_response(r):
|
|
raise BadResponse
|
|
return r
|
|
|
|
|
|
def _net_read(sock, count, expiration):
|
|
"""Read the specified number of bytes from sock. Keep trying until we
|
|
either get the desired amount, or we hit EOF.
|
|
A Timeout exception will be raised if the operation is not completed
|
|
by the expiration time.
|
|
"""
|
|
s = b''
|
|
while count > 0:
|
|
_wait_for_readable(sock, expiration)
|
|
n = sock.recv(count)
|
|
if n == b'':
|
|
raise EOFError
|
|
count = count - len(n)
|
|
s = s + n
|
|
return s
|
|
|
|
|
|
def _net_write(sock, data, expiration):
|
|
"""Write the specified data to the socket.
|
|
A Timeout exception will be raised if the operation is not completed
|
|
by the expiration time.
|
|
"""
|
|
current = 0
|
|
l = len(data)
|
|
while current < l:
|
|
_wait_for_writable(sock, expiration)
|
|
current += sock.send(data[current:])
|
|
|
|
|
|
def send_tcp(sock, what, expiration=None):
|
|
"""Send a DNS message to the specified TCP socket.
|
|
|
|
*sock*, a ``socket``.
|
|
|
|
*what*, a ``binary`` or ``dns.message.Message``, the message to send.
|
|
|
|
*expiration*, a ``float`` or ``None``, the absolute time at which
|
|
a timeout exception should be raised. If ``None``, no timeout will
|
|
occur.
|
|
|
|
Returns an ``(int, float)`` tuple of bytes sent and the sent time.
|
|
"""
|
|
|
|
if isinstance(what, dns.message.Message):
|
|
what = what.to_wire()
|
|
l = len(what)
|
|
# copying the wire into tcpmsg is inefficient, but lets us
|
|
# avoid writev() or doing a short write that would get pushed
|
|
# onto the net
|
|
tcpmsg = struct.pack("!H", l) + what
|
|
_wait_for_writable(sock, expiration)
|
|
sent_time = time.time()
|
|
_net_write(sock, tcpmsg, expiration)
|
|
return (len(tcpmsg), sent_time)
|
|
|
|
def receive_tcp(sock, expiration=None, one_rr_per_rrset=False,
|
|
keyring=None, request_mac=b'', ignore_trailing=False):
|
|
"""Read a DNS message from a TCP socket.
|
|
|
|
*sock*, a ``socket``.
|
|
|
|
*expiration*, a ``float`` or ``None``, the absolute time at which
|
|
a timeout exception should be raised. If ``None``, no timeout will
|
|
occur.
|
|
|
|
*one_rr_per_rrset*, a ``bool``. If ``True``, put each RR into its own
|
|
RRset.
|
|
|
|
*keyring*, a ``dict``, the keyring to use for TSIG.
|
|
|
|
*request_mac*, a ``binary``, the MAC of the request (for TSIG).
|
|
|
|
*ignore_trailing*, a ``bool``. If ``True``, ignore trailing
|
|
junk at end of the received message.
|
|
|
|
Raises if the message is malformed, if network errors occur, of if
|
|
there is a timeout.
|
|
|
|
Returns a ``dns.message.Message`` object.
|
|
"""
|
|
|
|
ldata = _net_read(sock, 2, expiration)
|
|
(l,) = struct.unpack("!H", ldata)
|
|
wire = _net_read(sock, l, expiration)
|
|
received_time = time.time()
|
|
r = dns.message.from_wire(wire, keyring=keyring, request_mac=request_mac,
|
|
one_rr_per_rrset=one_rr_per_rrset,
|
|
ignore_trailing=ignore_trailing)
|
|
return (r, received_time)
|
|
|
|
def _connect(s, address):
|
|
try:
|
|
s.connect(address)
|
|
except socket.error:
|
|
(ty, v) = sys.exc_info()[:2]
|
|
|
|
if hasattr(v, 'errno'):
|
|
v_err = v.errno
|
|
else:
|
|
v_err = v[0]
|
|
if v_err not in [errno.EINPROGRESS, errno.EWOULDBLOCK, errno.EALREADY]:
|
|
raise v
|
|
|
|
|
|
def tcp(q, where, timeout=None, port=53, af=None, source=None, source_port=0,
|
|
one_rr_per_rrset=False, ignore_trailing=False):
|
|
"""Return the response obtained after sending a query via TCP.
|
|
|
|
*q*, a ``dns.message.Message``, the query to send
|
|
|
|
*where*, a ``text`` containing an IPv4 or IPv6 address, where
|
|
to send the message.
|
|
|
|
*timeout*, a ``float`` or ``None``, the number of seconds to wait before the
|
|
query times out. If ``None``, the default, wait forever.
|
|
|
|
*port*, an ``int``, the port send the message to. The default is 53.
|
|
|
|
*af*, an ``int``, the address family to use. The default is ``None``,
|
|
which causes the address family to use to be inferred from the form of
|
|
*where*. If the inference attempt fails, AF_INET is used. This
|
|
parameter is historical; you need never set it.
|
|
|
|
*source*, a ``text`` containing an IPv4 or IPv6 address, specifying
|
|
the source address. The default is the wildcard address.
|
|
|
|
*source_port*, an ``int``, the port from which to send the message.
|
|
The default is 0.
|
|
|
|
*one_rr_per_rrset*, a ``bool``. If ``True``, put each RR into its own
|
|
RRset.
|
|
|
|
*ignore_trailing*, a ``bool``. If ``True``, ignore trailing
|
|
junk at end of the received message.
|
|
|
|
Returns a ``dns.message.Message``.
|
|
"""
|
|
|
|
wire = q.to_wire()
|
|
(af, destination, source) = _destination_and_source(af, where, port,
|
|
source, source_port)
|
|
s = socket_factory(af, socket.SOCK_STREAM, 0)
|
|
begin_time = None
|
|
received_time = None
|
|
try:
|
|
expiration = _compute_expiration(timeout)
|
|
s.setblocking(0)
|
|
begin_time = time.time()
|
|
if source is not None:
|
|
s.bind(source)
|
|
_connect(s, destination)
|
|
send_tcp(s, wire, expiration)
|
|
(r, received_time) = receive_tcp(s, expiration, one_rr_per_rrset,
|
|
q.keyring, q.mac, ignore_trailing)
|
|
finally:
|
|
if begin_time is None or received_time is None:
|
|
response_time = 0
|
|
else:
|
|
response_time = received_time - begin_time
|
|
s.close()
|
|
r.time = response_time
|
|
if not q.is_response(r):
|
|
raise BadResponse
|
|
return r
|
|
|
|
|
|
def xfr(where, zone, rdtype=dns.rdatatype.AXFR, rdclass=dns.rdataclass.IN,
|
|
timeout=None, port=53, keyring=None, keyname=None, relativize=True,
|
|
af=None, lifetime=None, source=None, source_port=0, serial=0,
|
|
use_udp=False, keyalgorithm=dns.tsig.default_algorithm):
|
|
"""Return a generator for the responses to a zone transfer.
|
|
|
|
*where*. If the inference attempt fails, AF_INET is used. This
|
|
parameter is historical; you need never set it.
|
|
|
|
*zone*, a ``dns.name.Name`` or ``text``, the name of the zone to transfer.
|
|
|
|
*rdtype*, an ``int`` or ``text``, the type of zone transfer. The
|
|
default is ``dns.rdatatype.AXFR``. ``dns.rdatatype.IXFR`` can be
|
|
used to do an incremental transfer instead.
|
|
|
|
*rdclass*, an ``int`` or ``text``, the class of the zone transfer.
|
|
The default is ``dns.rdataclass.IN``.
|
|
|
|
*timeout*, a ``float``, the number of seconds to wait for each
|
|
response message. If None, the default, wait forever.
|
|
|
|
*port*, an ``int``, the port send the message to. The default is 53.
|
|
|
|
*keyring*, a ``dict``, the keyring to use for TSIG.
|
|
|
|
*keyname*, a ``dns.name.Name`` or ``text``, the name of the TSIG
|
|
key to use.
|
|
|
|
*relativize*, a ``bool``. If ``True``, all names in the zone will be
|
|
relativized to the zone origin. It is essential that the
|
|
relativize setting matches the one specified to
|
|
``dns.zone.from_xfr()`` if using this generator to make a zone.
|
|
|
|
*af*, an ``int``, the address family to use. The default is ``None``,
|
|
which causes the address family to use to be inferred from the form of
|
|
*where*. If the inference attempt fails, AF_INET is used. This
|
|
parameter is historical; you need never set it.
|
|
|
|
*lifetime*, a ``float``, the total number of seconds to spend
|
|
doing the transfer. If ``None``, the default, then there is no
|
|
limit on the time the transfer may take.
|
|
|
|
*source*, a ``text`` containing an IPv4 or IPv6 address, specifying
|
|
the source address. The default is the wildcard address.
|
|
|
|
*source_port*, an ``int``, the port from which to send the message.
|
|
The default is 0.
|
|
|
|
*serial*, an ``int``, the SOA serial number to use as the base for
|
|
an IXFR diff sequence (only meaningful if *rdtype* is
|
|
``dns.rdatatype.IXFR``).
|
|
|
|
*use_udp*, a ``bool``. If ``True``, use UDP (only meaningful for IXFR).
|
|
|
|
*keyalgorithm*, a ``dns.name.Name`` or ``text``, the TSIG algorithm to use.
|
|
|
|
Raises on errors, and so does the generator.
|
|
|
|
Returns a generator of ``dns.message.Message`` objects.
|
|
"""
|
|
|
|
if isinstance(zone, string_types):
|
|
zone = dns.name.from_text(zone)
|
|
if isinstance(rdtype, string_types):
|
|
rdtype = dns.rdatatype.from_text(rdtype)
|
|
q = dns.message.make_query(zone, rdtype, rdclass)
|
|
if rdtype == dns.rdatatype.IXFR:
|
|
rrset = dns.rrset.from_text(zone, 0, 'IN', 'SOA',
|
|
'. . %u 0 0 0 0' % serial)
|
|
q.authority.append(rrset)
|
|
if keyring is not None:
|
|
q.use_tsig(keyring, keyname, algorithm=keyalgorithm)
|
|
wire = q.to_wire()
|
|
(af, destination, source) = _destination_and_source(af, where, port,
|
|
source, source_port)
|
|
if use_udp:
|
|
if rdtype != dns.rdatatype.IXFR:
|
|
raise ValueError('cannot do a UDP AXFR')
|
|
s = socket_factory(af, socket.SOCK_DGRAM, 0)
|
|
else:
|
|
s = socket_factory(af, socket.SOCK_STREAM, 0)
|
|
s.setblocking(0)
|
|
if source is not None:
|
|
s.bind(source)
|
|
expiration = _compute_expiration(lifetime)
|
|
_connect(s, destination)
|
|
l = len(wire)
|
|
if use_udp:
|
|
_wait_for_writable(s, expiration)
|
|
s.send(wire)
|
|
else:
|
|
tcpmsg = struct.pack("!H", l) + wire
|
|
_net_write(s, tcpmsg, expiration)
|
|
done = False
|
|
delete_mode = True
|
|
expecting_SOA = False
|
|
soa_rrset = None
|
|
if relativize:
|
|
origin = zone
|
|
oname = dns.name.empty
|
|
else:
|
|
origin = None
|
|
oname = zone
|
|
tsig_ctx = None
|
|
first = True
|
|
while not done:
|
|
mexpiration = _compute_expiration(timeout)
|
|
if mexpiration is None or mexpiration > expiration:
|
|
mexpiration = expiration
|
|
if use_udp:
|
|
_wait_for_readable(s, expiration)
|
|
(wire, from_address) = s.recvfrom(65535)
|
|
else:
|
|
ldata = _net_read(s, 2, mexpiration)
|
|
(l,) = struct.unpack("!H", ldata)
|
|
wire = _net_read(s, l, mexpiration)
|
|
is_ixfr = (rdtype == dns.rdatatype.IXFR)
|
|
r = dns.message.from_wire(wire, keyring=q.keyring, request_mac=q.mac,
|
|
xfr=True, origin=origin, tsig_ctx=tsig_ctx,
|
|
multi=True, first=first,
|
|
one_rr_per_rrset=is_ixfr)
|
|
rcode = r.rcode()
|
|
if rcode != dns.rcode.NOERROR:
|
|
raise TransferError(rcode)
|
|
tsig_ctx = r.tsig_ctx
|
|
first = False
|
|
answer_index = 0
|
|
if soa_rrset is None:
|
|
if not r.answer or r.answer[0].name != oname:
|
|
raise dns.exception.FormError(
|
|
"No answer or RRset not for qname")
|
|
rrset = r.answer[0]
|
|
if rrset.rdtype != dns.rdatatype.SOA:
|
|
raise dns.exception.FormError("first RRset is not an SOA")
|
|
answer_index = 1
|
|
soa_rrset = rrset.copy()
|
|
if rdtype == dns.rdatatype.IXFR:
|
|
if soa_rrset[0].serial <= serial:
|
|
#
|
|
# We're already up-to-date.
|
|
#
|
|
done = True
|
|
else:
|
|
expecting_SOA = True
|
|
#
|
|
# Process SOAs in the answer section (other than the initial
|
|
# SOA in the first message).
|
|
#
|
|
for rrset in r.answer[answer_index:]:
|
|
if done:
|
|
raise dns.exception.FormError("answers after final SOA")
|
|
if rrset.rdtype == dns.rdatatype.SOA and rrset.name == oname:
|
|
if expecting_SOA:
|
|
if rrset[0].serial != serial:
|
|
raise dns.exception.FormError(
|
|
"IXFR base serial mismatch")
|
|
expecting_SOA = False
|
|
elif rdtype == dns.rdatatype.IXFR:
|
|
delete_mode = not delete_mode
|
|
#
|
|
# If this SOA RRset is equal to the first we saw then we're
|
|
# finished. If this is an IXFR we also check that we're seeing
|
|
# the record in the expected part of the response.
|
|
#
|
|
if rrset == soa_rrset and \
|
|
(rdtype == dns.rdatatype.AXFR or
|
|
(rdtype == dns.rdatatype.IXFR and delete_mode)):
|
|
done = True
|
|
elif expecting_SOA:
|
|
#
|
|
# We made an IXFR request and are expecting another
|
|
# SOA RR, but saw something else, so this must be an
|
|
# AXFR response.
|
|
#
|
|
rdtype = dns.rdatatype.AXFR
|
|
expecting_SOA = False
|
|
if done and q.keyring and not r.had_tsig:
|
|
raise dns.exception.FormError("missing TSIG")
|
|
yield r
|
|
s.close()
|