1520 lines
51 KiB
Python
1520 lines
51 KiB
Python
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
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# Copyright (C) 2003-2017 Nominum, Inc.
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#
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# Permission to use, copy, modify, and distribute this software and its
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# documentation for any purpose with or without fee is hereby granted,
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# provided that the above copyright notice and this permission notice
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# appear in all copies.
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#
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# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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"""Talk to a DNS server."""
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import base64
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import contextlib
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import enum
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import errno
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import os
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import selectors
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import socket
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import struct
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import time
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from typing import Any, Dict, Optional, Tuple, Union
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import dns.exception
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import dns.inet
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import dns.message
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import dns.name
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import dns.quic
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import dns.rcode
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import dns.rdataclass
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import dns.rdatatype
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import dns.serial
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import dns.transaction
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import dns.tsig
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import dns.xfr
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def _remaining(expiration):
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if expiration is None:
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return None
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timeout = expiration - time.time()
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if timeout <= 0.0:
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raise dns.exception.Timeout
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return timeout
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def _expiration_for_this_attempt(timeout, expiration):
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if expiration is None:
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return None
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return min(time.time() + timeout, expiration)
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_have_httpx = False
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_have_http2 = False
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try:
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import httpcore
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import httpcore._backends.sync
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import httpx
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_CoreNetworkBackend = httpcore.NetworkBackend
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_CoreSyncStream = httpcore._backends.sync.SyncStream
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_have_httpx = True
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try:
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# See if http2 support is available.
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with httpx.Client(http2=True):
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_have_http2 = True
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except Exception:
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pass
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class _NetworkBackend(_CoreNetworkBackend):
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def __init__(self, resolver, local_port, bootstrap_address, family):
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super().__init__()
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self._local_port = local_port
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self._resolver = resolver
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self._bootstrap_address = bootstrap_address
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self._family = family
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def connect_tcp(
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self, host, port, timeout, local_address, socket_options=None
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): # pylint: disable=signature-differs
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addresses = []
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_, expiration = _compute_times(timeout)
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if dns.inet.is_address(host):
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addresses.append(host)
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elif self._bootstrap_address is not None:
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addresses.append(self._bootstrap_address)
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else:
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timeout = _remaining(expiration)
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family = self._family
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if local_address:
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family = dns.inet.af_for_address(local_address)
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answers = self._resolver.resolve_name(
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host, family=family, lifetime=timeout
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)
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addresses = answers.addresses()
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for address in addresses:
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af = dns.inet.af_for_address(address)
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if local_address is not None or self._local_port != 0:
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source = dns.inet.low_level_address_tuple(
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(local_address, self._local_port), af
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)
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else:
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source = None
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sock = _make_socket(af, socket.SOCK_STREAM, source)
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attempt_expiration = _expiration_for_this_attempt(2.0, expiration)
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try:
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_connect(
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sock,
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dns.inet.low_level_address_tuple((address, port), af),
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attempt_expiration,
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)
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return _CoreSyncStream(sock)
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except Exception:
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pass
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raise httpcore.ConnectError
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def connect_unix_socket(
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self, path, timeout, socket_options=None
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): # pylint: disable=signature-differs
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raise NotImplementedError
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class _HTTPTransport(httpx.HTTPTransport):
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def __init__(
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self,
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*args,
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local_port=0,
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bootstrap_address=None,
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resolver=None,
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family=socket.AF_UNSPEC,
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**kwargs,
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):
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if resolver is None:
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# pylint: disable=import-outside-toplevel,redefined-outer-name
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import dns.resolver
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resolver = dns.resolver.Resolver()
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super().__init__(*args, **kwargs)
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self._pool._network_backend = _NetworkBackend(
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resolver, local_port, bootstrap_address, family
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)
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except ImportError: # pragma: no cover
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class _HTTPTransport: # type: ignore
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def connect_tcp(self, host, port, timeout, local_address):
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raise NotImplementedError
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have_doh = _have_httpx
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try:
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import ssl
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except ImportError: # pragma: no cover
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class ssl: # type: ignore
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class WantReadException(Exception):
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pass
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class WantWriteException(Exception):
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pass
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class SSLContext:
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pass
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class SSLSocket:
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pass
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@classmethod
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def create_default_context(cls, *args, **kwargs):
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raise Exception("no ssl support") # pylint: disable=broad-exception-raised
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# Function used to create a socket. Can be overridden if needed in special
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# situations.
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socket_factory = socket.socket
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class UnexpectedSource(dns.exception.DNSException):
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"""A DNS query response came from an unexpected address or port."""
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class BadResponse(dns.exception.FormError):
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"""A DNS query response does not respond to the question asked."""
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class NoDOH(dns.exception.DNSException):
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"""DNS over HTTPS (DOH) was requested but the httpx module is not
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available."""
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class NoDOQ(dns.exception.DNSException):
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"""DNS over QUIC (DOQ) was requested but the aioquic module is not
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available."""
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# for backwards compatibility
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TransferError = dns.xfr.TransferError
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def _compute_times(timeout):
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now = time.time()
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if timeout is None:
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return (now, None)
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else:
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return (now, now + timeout)
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def _wait_for(fd, readable, writable, _, expiration):
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# Use the selected selector class to wait for any of the specified
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# events. An "expiration" absolute time is converted into a relative
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# timeout.
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#
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# The unused parameter is 'error', which is always set when
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# selecting for read or write, and we have no error-only selects.
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if readable and isinstance(fd, ssl.SSLSocket) and fd.pending() > 0:
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return True
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sel = _selector_class()
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events = 0
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if readable:
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events |= selectors.EVENT_READ
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if writable:
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events |= selectors.EVENT_WRITE
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if events:
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sel.register(fd, events)
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if expiration is None:
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timeout = None
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else:
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timeout = expiration - time.time()
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if timeout <= 0.0:
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raise dns.exception.Timeout
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if not sel.select(timeout):
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raise dns.exception.Timeout
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def _set_selector_class(selector_class):
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# Internal API. Do not use.
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global _selector_class
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_selector_class = selector_class
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if hasattr(selectors, "PollSelector"):
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# Prefer poll() on platforms that support it because it has no
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# limits on the maximum value of a file descriptor (plus it will
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# be more efficient for high values).
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#
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# We ignore typing here as we can't say _selector_class is Any
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# on python < 3.8 due to a bug.
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_selector_class = selectors.PollSelector # type: ignore
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else:
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_selector_class = selectors.SelectSelector # type: ignore
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def _wait_for_readable(s, expiration):
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_wait_for(s, True, False, True, expiration)
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def _wait_for_writable(s, expiration):
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_wait_for(s, False, True, True, expiration)
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def _addresses_equal(af, a1, a2):
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# Convert the first value of the tuple, which is a textual format
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# address into binary form, so that we are not confused by different
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# textual representations of the same address
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try:
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n1 = dns.inet.inet_pton(af, a1[0])
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n2 = dns.inet.inet_pton(af, a2[0])
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except dns.exception.SyntaxError:
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return False
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return n1 == n2 and a1[1:] == a2[1:]
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def _matches_destination(af, from_address, destination, ignore_unexpected):
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# Check that from_address is appropriate for a response to a query
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# sent to destination.
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if not destination:
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return True
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if _addresses_equal(af, from_address, destination) or (
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dns.inet.is_multicast(destination[0]) and from_address[1:] == destination[1:]
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):
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return True
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elif ignore_unexpected:
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return False
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raise UnexpectedSource(
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f"got a response from {from_address} instead of " f"{destination}"
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)
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def _destination_and_source(
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where, port, source, source_port, where_must_be_address=True
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):
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# Apply defaults and compute destination and source tuples
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# suitable for use in connect(), sendto(), or bind().
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af = None
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destination = None
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try:
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af = dns.inet.af_for_address(where)
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destination = where
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except Exception:
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if where_must_be_address:
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raise
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# URLs are ok so eat the exception
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if source:
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saf = dns.inet.af_for_address(source)
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if af:
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# We know the destination af, so source had better agree!
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if saf != af:
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raise ValueError(
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"different address families for source and destination"
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)
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else:
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# We didn't know the destination af, but we know the source,
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# so that's our af.
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af = saf
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if source_port and not source:
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# Caller has specified a source_port but not an address, so we
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# need to return a source, and we need to use the appropriate
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# wildcard address as the address.
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try:
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source = dns.inet.any_for_af(af)
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except Exception:
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# we catch this and raise ValueError for backwards compatibility
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raise ValueError("source_port specified but address family is unknown")
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# Convert high-level (address, port) tuples into low-level address
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# tuples.
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if destination:
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destination = dns.inet.low_level_address_tuple((destination, port), af)
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if source:
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source = dns.inet.low_level_address_tuple((source, source_port), af)
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return (af, destination, source)
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def _make_socket(af, type, source, ssl_context=None, server_hostname=None):
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s = socket_factory(af, type)
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try:
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s.setblocking(False)
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if source is not None:
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s.bind(source)
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if ssl_context:
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# LGTM gets a false positive here, as our default context is OK
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return ssl_context.wrap_socket(
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s,
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do_handshake_on_connect=False, # lgtm[py/insecure-protocol]
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server_hostname=server_hostname,
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)
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else:
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return s
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except Exception:
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s.close()
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raise
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def https(
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q: dns.message.Message,
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where: str,
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timeout: Optional[float] = None,
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port: int = 443,
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source: Optional[str] = None,
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source_port: int = 0,
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one_rr_per_rrset: bool = False,
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ignore_trailing: bool = False,
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session: Optional[Any] = None,
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path: str = "/dns-query",
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post: bool = True,
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bootstrap_address: Optional[str] = None,
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verify: Union[bool, str] = True,
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resolver: Optional["dns.resolver.Resolver"] = None,
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family: Optional[int] = socket.AF_UNSPEC,
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) -> dns.message.Message:
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"""Return the response obtained after sending a query via DNS-over-HTTPS.
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*q*, a ``dns.message.Message``, the query to send.
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*where*, a ``str``, the nameserver IP address or the full URL. If an IP address is
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given, the URL will be constructed using the following schema:
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https://<IP-address>:<port>/<path>.
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*timeout*, a ``float`` or ``None``, the number of seconds to wait before the query
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times out. If ``None``, the default, wait forever.
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*port*, a ``int``, the port to send the query to. The default is 443.
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*source*, a ``str`` containing an IPv4 or IPv6 address, specifying the source
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address. The default is the wildcard address.
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*source_port*, an ``int``, the port from which to send the message. The default is
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0.
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*one_rr_per_rrset*, a ``bool``. If ``True``, put each RR into its own RRset.
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*ignore_trailing*, a ``bool``. If ``True``, ignore trailing junk at end of the
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received message.
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*session*, an ``httpx.Client``. If provided, the client session to use to send the
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queries.
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*path*, a ``str``. If *where* is an IP address, then *path* will be used to
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construct the URL to send the DNS query to.
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*post*, a ``bool``. If ``True``, the default, POST method will be used.
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*bootstrap_address*, a ``str``, the IP address to use to bypass resolution.
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*verify*, a ``bool`` or ``str``. If a ``True``, then TLS certificate verification
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of the server is done using the default CA bundle; if ``False``, then no
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verification is done; if a `str` then it specifies the path to a certificate file or
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directory which will be used for verification.
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*resolver*, a ``dns.resolver.Resolver`` or ``None``, the resolver to use for
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resolution of hostnames in URLs. If not specified, a new resolver with a default
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configuration will be used; note this is *not* the default resolver as that resolver
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might have been configured to use DoH causing a chicken-and-egg problem. This
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parameter only has an effect if the HTTP library is httpx.
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*family*, an ``int``, the address family. If socket.AF_UNSPEC (the default), both A
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and AAAA records will be retrieved.
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Returns a ``dns.message.Message``.
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"""
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if not have_doh:
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raise NoDOH # pragma: no cover
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if session and not isinstance(session, httpx.Client):
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raise ValueError("session parameter must be an httpx.Client")
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wire = q.to_wire()
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(af, _, the_source) = _destination_and_source(
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where, port, source, source_port, False
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)
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transport = None
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headers = {"accept": "application/dns-message"}
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if af is not None and dns.inet.is_address(where):
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if af == socket.AF_INET:
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url = "https://{}:{}{}".format(where, port, path)
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elif af == socket.AF_INET6:
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url = "https://[{}]:{}{}".format(where, port, path)
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else:
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url = where
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# set source port and source address
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if the_source is None:
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local_address = None
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local_port = 0
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else:
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local_address = the_source[0]
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local_port = the_source[1]
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transport = _HTTPTransport(
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local_address=local_address,
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http1=True,
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http2=_have_http2,
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verify=verify,
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local_port=local_port,
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bootstrap_address=bootstrap_address,
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resolver=resolver,
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family=family,
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)
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if session:
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cm: contextlib.AbstractContextManager = contextlib.nullcontext(session)
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else:
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cm = httpx.Client(
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http1=True, http2=_have_http2, verify=verify, transport=transport
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)
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with cm as session:
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# see https://tools.ietf.org/html/rfc8484#section-4.1.1 for DoH
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# GET and POST examples
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if post:
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headers.update(
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{
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"content-type": "application/dns-message",
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"content-length": str(len(wire)),
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}
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)
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response = session.post(url, headers=headers, content=wire, timeout=timeout)
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else:
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wire = base64.urlsafe_b64encode(wire).rstrip(b"=")
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twire = wire.decode() # httpx does a repr() if we give it bytes
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response = session.get(
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url, headers=headers, timeout=timeout, params={"dns": twire}
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)
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# see https://tools.ietf.org/html/rfc8484#section-4.2.1 for info about DoH
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# status codes
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if response.status_code < 200 or response.status_code > 299:
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raise ValueError(
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"{} responded with status code {}"
|
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"\nResponse body: {}".format(where, response.status_code, response.content)
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)
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r = dns.message.from_wire(
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response.content,
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keyring=q.keyring,
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request_mac=q.request_mac,
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one_rr_per_rrset=one_rr_per_rrset,
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ignore_trailing=ignore_trailing,
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)
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r.time = response.elapsed.total_seconds()
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if not q.is_response(r):
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raise BadResponse
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return r
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|
|
|
|
def _udp_recv(sock, max_size, expiration):
|
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"""Reads a datagram from the socket.
|
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A Timeout exception will be raised if the operation is not completed
|
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by the expiration time.
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"""
|
|
while True:
|
|
try:
|
|
return sock.recvfrom(max_size)
|
|
except BlockingIOError:
|
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_wait_for_readable(sock, expiration)
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|
|
|
|
|
def _udp_send(sock, data, destination, expiration):
|
|
"""Sends the specified datagram to destination over the socket.
|
|
A Timeout exception will be raised if the operation is not completed
|
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by the expiration time.
|
|
"""
|
|
while True:
|
|
try:
|
|
if destination:
|
|
return sock.sendto(data, destination)
|
|
else:
|
|
return sock.send(data)
|
|
except BlockingIOError: # pragma: no cover
|
|
_wait_for_writable(sock, expiration)
|
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|
|
|
|
def send_udp(
|
|
sock: Any,
|
|
what: Union[dns.message.Message, bytes],
|
|
destination: Any,
|
|
expiration: Optional[float] = None,
|
|
) -> Tuple[int, float]:
|
|
"""Send a DNS message to the specified UDP socket.
|
|
|
|
*sock*, a ``socket``.
|
|
|
|
*what*, a ``bytes`` 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()
|
|
sent_time = time.time()
|
|
n = _udp_send(sock, what, destination, expiration)
|
|
return (n, sent_time)
|
|
|
|
|
|
def receive_udp(
|
|
sock: Any,
|
|
destination: Optional[Any] = None,
|
|
expiration: Optional[float] = None,
|
|
ignore_unexpected: bool = False,
|
|
one_rr_per_rrset: bool = False,
|
|
keyring: Optional[Dict[dns.name.Name, dns.tsig.Key]] = None,
|
|
request_mac: Optional[bytes] = b"",
|
|
ignore_trailing: bool = False,
|
|
raise_on_truncation: bool = False,
|
|
) -> Any:
|
|
"""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 message is expected to arrive from.
|
|
When receiving a response, this would be 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 ``bytes`` or ``None``, the MAC of the request (for TSIG).
|
|
|
|
*ignore_trailing*, a ``bool``. If ``True``, ignore trailing
|
|
junk at end of the received message.
|
|
|
|
*raise_on_truncation*, a ``bool``. If ``True``, raise an exception if
|
|
the TC bit is set.
|
|
|
|
Raises if the message is malformed, if network errors occur, of if
|
|
there is a timeout.
|
|
|
|
If *destination* is not ``None``, returns a ``(dns.message.Message, float)``
|
|
tuple of the received message and the received time.
|
|
|
|
If *destination* is ``None``, returns a
|
|
``(dns.message.Message, float, tuple)``
|
|
tuple of the received message, the received time, and the address where
|
|
the message arrived from.
|
|
"""
|
|
|
|
wire = b""
|
|
while True:
|
|
(wire, from_address) = _udp_recv(sock, 65535, expiration)
|
|
if _matches_destination(
|
|
sock.family, from_address, destination, ignore_unexpected
|
|
):
|
|
break
|
|
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,
|
|
raise_on_truncation=raise_on_truncation,
|
|
)
|
|
if destination:
|
|
return (r, received_time)
|
|
else:
|
|
return (r, received_time, from_address)
|
|
|
|
|
|
def udp(
|
|
q: dns.message.Message,
|
|
where: str,
|
|
timeout: Optional[float] = None,
|
|
port: int = 53,
|
|
source: Optional[str] = None,
|
|
source_port: int = 0,
|
|
ignore_unexpected: bool = False,
|
|
one_rr_per_rrset: bool = False,
|
|
ignore_trailing: bool = False,
|
|
raise_on_truncation: bool = False,
|
|
sock: Optional[Any] = None,
|
|
) -> dns.message.Message:
|
|
"""Return the response obtained after sending a query via UDP.
|
|
|
|
*q*, a ``dns.message.Message``, the query to send
|
|
|
|
*where*, a ``str`` 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.
|
|
|
|
*source*, a ``str`` 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.
|
|
|
|
*raise_on_truncation*, a ``bool``. If ``True``, raise an exception if
|
|
the TC bit is set.
|
|
|
|
*sock*, a ``socket.socket``, or ``None``, the socket to use for the
|
|
query. If ``None``, the default, a socket is created. Note that
|
|
if a socket is provided, it must be a nonblocking datagram socket,
|
|
and the *source* and *source_port* are ignored.
|
|
|
|
Returns a ``dns.message.Message``.
|
|
"""
|
|
|
|
wire = q.to_wire()
|
|
(af, destination, source) = _destination_and_source(
|
|
where, port, source, source_port
|
|
)
|
|
(begin_time, expiration) = _compute_times(timeout)
|
|
if sock:
|
|
cm: contextlib.AbstractContextManager = contextlib.nullcontext(sock)
|
|
else:
|
|
cm = _make_socket(af, socket.SOCK_DGRAM, source)
|
|
with cm as s:
|
|
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,
|
|
raise_on_truncation,
|
|
)
|
|
r.time = received_time - begin_time
|
|
if not q.is_response(r):
|
|
raise BadResponse
|
|
return r
|
|
assert (
|
|
False # help mypy figure out we can't get here lgtm[py/unreachable-statement]
|
|
)
|
|
|
|
|
|
def udp_with_fallback(
|
|
q: dns.message.Message,
|
|
where: str,
|
|
timeout: Optional[float] = None,
|
|
port: int = 53,
|
|
source: Optional[str] = None,
|
|
source_port: int = 0,
|
|
ignore_unexpected: bool = False,
|
|
one_rr_per_rrset: bool = False,
|
|
ignore_trailing: bool = False,
|
|
udp_sock: Optional[Any] = None,
|
|
tcp_sock: Optional[Any] = None,
|
|
) -> Tuple[dns.message.Message, bool]:
|
|
"""Return the response to the query, trying UDP first and falling back
|
|
to TCP if UDP results in a truncated response.
|
|
|
|
*q*, a ``dns.message.Message``, the query to send
|
|
|
|
*where*, a ``str`` 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.
|
|
|
|
*source*, a ``str`` 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.
|
|
|
|
*udp_sock*, a ``socket.socket``, or ``None``, the socket to use for the
|
|
UDP query. If ``None``, the default, a socket is created. Note that
|
|
if a socket is provided, it must be a nonblocking datagram socket,
|
|
and the *source* and *source_port* are ignored for the UDP query.
|
|
|
|
*tcp_sock*, a ``socket.socket``, or ``None``, the connected socket to use for the
|
|
TCP query. If ``None``, the default, a socket is created. Note that
|
|
if a socket is provided, it must be a nonblocking connected stream
|
|
socket, and *where*, *source* and *source_port* are ignored for the TCP
|
|
query.
|
|
|
|
Returns a (``dns.message.Message``, tcp) tuple where tcp is ``True``
|
|
if and only if TCP was used.
|
|
"""
|
|
try:
|
|
response = udp(
|
|
q,
|
|
where,
|
|
timeout,
|
|
port,
|
|
source,
|
|
source_port,
|
|
ignore_unexpected,
|
|
one_rr_per_rrset,
|
|
ignore_trailing,
|
|
True,
|
|
udp_sock,
|
|
)
|
|
return (response, False)
|
|
except dns.message.Truncated:
|
|
response = tcp(
|
|
q,
|
|
where,
|
|
timeout,
|
|
port,
|
|
source,
|
|
source_port,
|
|
one_rr_per_rrset,
|
|
ignore_trailing,
|
|
tcp_sock,
|
|
)
|
|
return (response, True)
|
|
|
|
|
|
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:
|
|
try:
|
|
n = sock.recv(count)
|
|
if n == b"":
|
|
raise EOFError
|
|
count -= len(n)
|
|
s += n
|
|
except (BlockingIOError, ssl.SSLWantReadError):
|
|
_wait_for_readable(sock, expiration)
|
|
except ssl.SSLWantWriteError: # pragma: no cover
|
|
_wait_for_writable(sock, expiration)
|
|
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:
|
|
try:
|
|
current += sock.send(data[current:])
|
|
except (BlockingIOError, ssl.SSLWantWriteError):
|
|
_wait_for_writable(sock, expiration)
|
|
except ssl.SSLWantReadError: # pragma: no cover
|
|
_wait_for_readable(sock, expiration)
|
|
|
|
|
|
def send_tcp(
|
|
sock: Any,
|
|
what: Union[dns.message.Message, bytes],
|
|
expiration: Optional[float] = None,
|
|
) -> Tuple[int, float]:
|
|
"""Send a DNS message to the specified TCP socket.
|
|
|
|
*sock*, a ``socket``.
|
|
|
|
*what*, a ``bytes`` 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):
|
|
wire = what.to_wire()
|
|
else:
|
|
wire = what
|
|
l = len(wire)
|
|
# 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) + wire
|
|
sent_time = time.time()
|
|
_net_write(sock, tcpmsg, expiration)
|
|
return (len(tcpmsg), sent_time)
|
|
|
|
|
|
def receive_tcp(
|
|
sock: Any,
|
|
expiration: Optional[float] = None,
|
|
one_rr_per_rrset: bool = False,
|
|
keyring: Optional[Dict[dns.name.Name, dns.tsig.Key]] = None,
|
|
request_mac: Optional[bytes] = b"",
|
|
ignore_trailing: bool = False,
|
|
) -> Tuple[dns.message.Message, float]:
|
|
"""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 ``bytes`` or ``None``, 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, float)`` tuple of the received message
|
|
and the received time.
|
|
"""
|
|
|
|
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, expiration):
|
|
err = s.connect_ex(address)
|
|
if err == 0:
|
|
return
|
|
if err in (errno.EINPROGRESS, errno.EWOULDBLOCK, errno.EALREADY):
|
|
_wait_for_writable(s, expiration)
|
|
err = s.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
|
|
if err != 0:
|
|
raise OSError(err, os.strerror(err))
|
|
|
|
|
|
def tcp(
|
|
q: dns.message.Message,
|
|
where: str,
|
|
timeout: Optional[float] = None,
|
|
port: int = 53,
|
|
source: Optional[str] = None,
|
|
source_port: int = 0,
|
|
one_rr_per_rrset: bool = False,
|
|
ignore_trailing: bool = False,
|
|
sock: Optional[Any] = None,
|
|
) -> dns.message.Message:
|
|
"""Return the response obtained after sending a query via TCP.
|
|
|
|
*q*, a ``dns.message.Message``, the query to send
|
|
|
|
*where*, a ``str`` 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.
|
|
|
|
*source*, a ``str`` 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.
|
|
|
|
*sock*, a ``socket.socket``, or ``None``, the connected socket to use for the
|
|
query. If ``None``, the default, a socket is created. Note that
|
|
if a socket is provided, it must be a nonblocking connected stream
|
|
socket, and *where*, *port*, *source* and *source_port* are ignored.
|
|
|
|
Returns a ``dns.message.Message``.
|
|
"""
|
|
|
|
wire = q.to_wire()
|
|
(begin_time, expiration) = _compute_times(timeout)
|
|
if sock:
|
|
cm: contextlib.AbstractContextManager = contextlib.nullcontext(sock)
|
|
else:
|
|
(af, destination, source) = _destination_and_source(
|
|
where, port, source, source_port
|
|
)
|
|
cm = _make_socket(af, socket.SOCK_STREAM, source)
|
|
with cm as s:
|
|
if not sock:
|
|
_connect(s, destination, expiration)
|
|
send_tcp(s, wire, expiration)
|
|
(r, received_time) = receive_tcp(
|
|
s, expiration, one_rr_per_rrset, q.keyring, q.mac, ignore_trailing
|
|
)
|
|
r.time = received_time - begin_time
|
|
if not q.is_response(r):
|
|
raise BadResponse
|
|
return r
|
|
assert (
|
|
False # help mypy figure out we can't get here lgtm[py/unreachable-statement]
|
|
)
|
|
|
|
|
|
def _tls_handshake(s, expiration):
|
|
while True:
|
|
try:
|
|
s.do_handshake()
|
|
return
|
|
except ssl.SSLWantReadError:
|
|
_wait_for_readable(s, expiration)
|
|
except ssl.SSLWantWriteError: # pragma: no cover
|
|
_wait_for_writable(s, expiration)
|
|
|
|
|
|
def tls(
|
|
q: dns.message.Message,
|
|
where: str,
|
|
timeout: Optional[float] = None,
|
|
port: int = 853,
|
|
source: Optional[str] = None,
|
|
source_port: int = 0,
|
|
one_rr_per_rrset: bool = False,
|
|
ignore_trailing: bool = False,
|
|
sock: Optional[ssl.SSLSocket] = None,
|
|
ssl_context: Optional[ssl.SSLContext] = None,
|
|
server_hostname: Optional[str] = None,
|
|
) -> dns.message.Message:
|
|
"""Return the response obtained after sending a query via TLS.
|
|
|
|
*q*, a ``dns.message.Message``, the query to send
|
|
|
|
*where*, a ``str`` 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 853.
|
|
|
|
*source*, a ``str`` 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.
|
|
|
|
*sock*, an ``ssl.SSLSocket``, or ``None``, the socket to use for
|
|
the query. If ``None``, the default, a socket is created. Note
|
|
that if a socket is provided, it must be a nonblocking connected
|
|
SSL stream socket, and *where*, *port*, *source*, *source_port*,
|
|
and *ssl_context* are ignored.
|
|
|
|
*ssl_context*, an ``ssl.SSLContext``, the context to use when establishing
|
|
a TLS connection. If ``None``, the default, creates one with the default
|
|
configuration.
|
|
|
|
*server_hostname*, a ``str`` containing the server's hostname. The
|
|
default is ``None``, which means that no hostname is known, and if an
|
|
SSL context is created, hostname checking will be disabled.
|
|
|
|
Returns a ``dns.message.Message``.
|
|
|
|
"""
|
|
|
|
if sock:
|
|
#
|
|
# If a socket was provided, there's no special TLS handling needed.
|
|
#
|
|
return tcp(
|
|
q,
|
|
where,
|
|
timeout,
|
|
port,
|
|
source,
|
|
source_port,
|
|
one_rr_per_rrset,
|
|
ignore_trailing,
|
|
sock,
|
|
)
|
|
|
|
wire = q.to_wire()
|
|
(begin_time, expiration) = _compute_times(timeout)
|
|
(af, destination, source) = _destination_and_source(
|
|
where, port, source, source_port
|
|
)
|
|
if ssl_context is None and not sock:
|
|
ssl_context = ssl.create_default_context()
|
|
ssl_context.minimum_version = ssl.TLSVersion.TLSv1_2
|
|
if server_hostname is None:
|
|
ssl_context.check_hostname = False
|
|
|
|
with _make_socket(
|
|
af,
|
|
socket.SOCK_STREAM,
|
|
source,
|
|
ssl_context=ssl_context,
|
|
server_hostname=server_hostname,
|
|
) as s:
|
|
_connect(s, destination, expiration)
|
|
_tls_handshake(s, expiration)
|
|
send_tcp(s, wire, expiration)
|
|
(r, received_time) = receive_tcp(
|
|
s, expiration, one_rr_per_rrset, q.keyring, q.mac, ignore_trailing
|
|
)
|
|
r.time = received_time - begin_time
|
|
if not q.is_response(r):
|
|
raise BadResponse
|
|
return r
|
|
assert (
|
|
False # help mypy figure out we can't get here lgtm[py/unreachable-statement]
|
|
)
|
|
|
|
|
|
def quic(
|
|
q: dns.message.Message,
|
|
where: str,
|
|
timeout: Optional[float] = None,
|
|
port: int = 853,
|
|
source: Optional[str] = None,
|
|
source_port: int = 0,
|
|
one_rr_per_rrset: bool = False,
|
|
ignore_trailing: bool = False,
|
|
connection: Optional[dns.quic.SyncQuicConnection] = None,
|
|
verify: Union[bool, str] = True,
|
|
server_hostname: Optional[str] = None,
|
|
) -> dns.message.Message:
|
|
"""Return the response obtained after sending a query via DNS-over-QUIC.
|
|
|
|
*q*, a ``dns.message.Message``, the query to send.
|
|
|
|
*where*, a ``str``, the nameserver IP address.
|
|
|
|
*timeout*, a ``float`` or ``None``, the number of seconds to wait before the query
|
|
times out. If ``None``, the default, wait forever.
|
|
|
|
*port*, a ``int``, the port to send the query to. The default is 853.
|
|
|
|
*source*, a ``str`` 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.
|
|
|
|
*connection*, a ``dns.quic.SyncQuicConnection``. If provided, the
|
|
connection to use to send the query.
|
|
|
|
*verify*, a ``bool`` or ``str``. If a ``True``, then TLS certificate verification
|
|
of the server is done using the default CA bundle; if ``False``, then no
|
|
verification is done; if a `str` then it specifies the path to a certificate file or
|
|
directory which will be used for verification.
|
|
|
|
*server_hostname*, a ``str`` containing the server's hostname. The
|
|
default is ``None``, which means that no hostname is known, and if an
|
|
SSL context is created, hostname checking will be disabled.
|
|
|
|
Returns a ``dns.message.Message``.
|
|
"""
|
|
|
|
if not dns.quic.have_quic:
|
|
raise NoDOQ("DNS-over-QUIC is not available.") # pragma: no cover
|
|
|
|
q.id = 0
|
|
wire = q.to_wire()
|
|
the_connection: dns.quic.SyncQuicConnection
|
|
the_manager: dns.quic.SyncQuicManager
|
|
if connection:
|
|
manager: contextlib.AbstractContextManager = contextlib.nullcontext(None)
|
|
the_connection = connection
|
|
else:
|
|
manager = dns.quic.SyncQuicManager(
|
|
verify_mode=verify, server_name=server_hostname
|
|
)
|
|
the_manager = manager # for type checking happiness
|
|
|
|
with manager:
|
|
if not connection:
|
|
the_connection = the_manager.connect(where, port, source, source_port)
|
|
(start, expiration) = _compute_times(timeout)
|
|
with the_connection.make_stream(timeout) as stream:
|
|
stream.send(wire, True)
|
|
wire = stream.receive(_remaining(expiration))
|
|
finish = time.time()
|
|
r = dns.message.from_wire(
|
|
wire,
|
|
keyring=q.keyring,
|
|
request_mac=q.request_mac,
|
|
one_rr_per_rrset=one_rr_per_rrset,
|
|
ignore_trailing=ignore_trailing,
|
|
)
|
|
r.time = max(finish - start, 0.0)
|
|
if not q.is_response(r):
|
|
raise BadResponse
|
|
return r
|
|
|
|
|
|
def xfr(
|
|
where: str,
|
|
zone: Union[dns.name.Name, str],
|
|
rdtype: Union[dns.rdatatype.RdataType, str] = dns.rdatatype.AXFR,
|
|
rdclass: Union[dns.rdataclass.RdataClass, str] = dns.rdataclass.IN,
|
|
timeout: Optional[float] = None,
|
|
port: int = 53,
|
|
keyring: Optional[Dict[dns.name.Name, dns.tsig.Key]] = None,
|
|
keyname: Optional[Union[dns.name.Name, str]] = None,
|
|
relativize: bool = True,
|
|
lifetime: Optional[float] = None,
|
|
source: Optional[str] = None,
|
|
source_port: int = 0,
|
|
serial: int = 0,
|
|
use_udp: bool = False,
|
|
keyalgorithm: Union[dns.name.Name, str] = dns.tsig.default_algorithm,
|
|
) -> Any:
|
|
"""Return a generator for the responses to a zone transfer.
|
|
|
|
*where*, a ``str`` containing an IPv4 or IPv6 address, where
|
|
to send the message.
|
|
|
|
*zone*, a ``dns.name.Name`` or ``str``, the name of the zone to transfer.
|
|
|
|
*rdtype*, an ``int`` or ``str``, 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 ``str``, 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 ``str``, 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.
|
|
|
|
*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 ``str`` 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 ``str``, the TSIG algorithm to use.
|
|
|
|
Raises on errors, and so does the generator.
|
|
|
|
Returns a generator of ``dns.message.Message`` objects.
|
|
"""
|
|
|
|
if isinstance(zone, str):
|
|
zone = dns.name.from_text(zone)
|
|
rdtype = dns.rdatatype.RdataType.make(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(
|
|
where, port, source, source_port
|
|
)
|
|
if use_udp and rdtype != dns.rdatatype.IXFR:
|
|
raise ValueError("cannot do a UDP AXFR")
|
|
sock_type = socket.SOCK_DGRAM if use_udp else socket.SOCK_STREAM
|
|
with _make_socket(af, sock_type, source) as s:
|
|
(_, expiration) = _compute_times(lifetime)
|
|
_connect(s, destination, expiration)
|
|
l = len(wire)
|
|
if use_udp:
|
|
_udp_send(s, wire, None, expiration)
|
|
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
|
|
while not done:
|
|
(_, mexpiration) = _compute_times(timeout)
|
|
if mexpiration is None or (
|
|
expiration is not None and mexpiration > expiration
|
|
):
|
|
mexpiration = expiration
|
|
if use_udp:
|
|
(wire, _) = _udp_recv(s, 65535, mexpiration)
|
|
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,
|
|
one_rr_per_rrset=is_ixfr,
|
|
)
|
|
rcode = r.rcode()
|
|
if rcode != dns.rcode.NOERROR:
|
|
raise TransferError(rcode)
|
|
tsig_ctx = r.tsig_ctx
|
|
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 dns.serial.Serial(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
|
|
|
|
|
|
class UDPMode(enum.IntEnum):
|
|
"""How should UDP be used in an IXFR from :py:func:`inbound_xfr()`?
|
|
|
|
NEVER means "never use UDP; always use TCP"
|
|
TRY_FIRST means "try to use UDP but fall back to TCP if needed"
|
|
ONLY means "raise ``dns.xfr.UseTCP`` if trying UDP does not succeed"
|
|
"""
|
|
|
|
NEVER = 0
|
|
TRY_FIRST = 1
|
|
ONLY = 2
|
|
|
|
|
|
def inbound_xfr(
|
|
where: str,
|
|
txn_manager: dns.transaction.TransactionManager,
|
|
query: Optional[dns.message.Message] = None,
|
|
port: int = 53,
|
|
timeout: Optional[float] = None,
|
|
lifetime: Optional[float] = None,
|
|
source: Optional[str] = None,
|
|
source_port: int = 0,
|
|
udp_mode: UDPMode = UDPMode.NEVER,
|
|
) -> None:
|
|
"""Conduct an inbound transfer and apply it via a transaction from the
|
|
txn_manager.
|
|
|
|
*where*, a ``str`` containing an IPv4 or IPv6 address, where
|
|
to send the message.
|
|
|
|
*txn_manager*, a ``dns.transaction.TransactionManager``, the txn_manager
|
|
for this transfer (typically a ``dns.zone.Zone``).
|
|
|
|
*query*, the query to send. If not supplied, a default query is
|
|
constructed using information from the *txn_manager*.
|
|
|
|
*port*, an ``int``, the port send the message to. The default is 53.
|
|
|
|
*timeout*, a ``float``, the number of seconds to wait for each
|
|
response message. If None, the default, wait forever.
|
|
|
|
*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 ``str`` 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.
|
|
|
|
*udp_mode*, a ``dns.query.UDPMode``, determines how UDP is used
|
|
for IXFRs. The default is ``dns.UDPMode.NEVER``, i.e. only use
|
|
TCP. Other possibilities are ``dns.UDPMode.TRY_FIRST``, which
|
|
means "try UDP but fallback to TCP if needed", and
|
|
``dns.UDPMode.ONLY``, which means "try UDP and raise
|
|
``dns.xfr.UseTCP`` if it does not succeed.
|
|
|
|
Raises on errors.
|
|
"""
|
|
if query is None:
|
|
(query, serial) = dns.xfr.make_query(txn_manager)
|
|
else:
|
|
serial = dns.xfr.extract_serial_from_query(query)
|
|
rdtype = query.question[0].rdtype
|
|
is_ixfr = rdtype == dns.rdatatype.IXFR
|
|
origin = txn_manager.from_wire_origin()
|
|
wire = query.to_wire()
|
|
(af, destination, source) = _destination_and_source(
|
|
where, port, source, source_port
|
|
)
|
|
(_, expiration) = _compute_times(lifetime)
|
|
retry = True
|
|
while retry:
|
|
retry = False
|
|
if is_ixfr and udp_mode != UDPMode.NEVER:
|
|
sock_type = socket.SOCK_DGRAM
|
|
is_udp = True
|
|
else:
|
|
sock_type = socket.SOCK_STREAM
|
|
is_udp = False
|
|
with _make_socket(af, sock_type, source) as s:
|
|
_connect(s, destination, expiration)
|
|
if is_udp:
|
|
_udp_send(s, wire, None, expiration)
|
|
else:
|
|
tcpmsg = struct.pack("!H", len(wire)) + wire
|
|
_net_write(s, tcpmsg, expiration)
|
|
with dns.xfr.Inbound(txn_manager, rdtype, serial, is_udp) as inbound:
|
|
done = False
|
|
tsig_ctx = None
|
|
while not done:
|
|
(_, mexpiration) = _compute_times(timeout)
|
|
if mexpiration is None or (
|
|
expiration is not None and mexpiration > expiration
|
|
):
|
|
mexpiration = expiration
|
|
if is_udp:
|
|
(rwire, _) = _udp_recv(s, 65535, mexpiration)
|
|
else:
|
|
ldata = _net_read(s, 2, mexpiration)
|
|
(l,) = struct.unpack("!H", ldata)
|
|
rwire = _net_read(s, l, mexpiration)
|
|
r = dns.message.from_wire(
|
|
rwire,
|
|
keyring=query.keyring,
|
|
request_mac=query.mac,
|
|
xfr=True,
|
|
origin=origin,
|
|
tsig_ctx=tsig_ctx,
|
|
multi=(not is_udp),
|
|
one_rr_per_rrset=is_ixfr,
|
|
)
|
|
try:
|
|
done = inbound.process_message(r)
|
|
except dns.xfr.UseTCP:
|
|
assert is_udp # should not happen if we used TCP!
|
|
if udp_mode == UDPMode.ONLY:
|
|
raise
|
|
done = True
|
|
retry = True
|
|
udp_mode = UDPMode.NEVER
|
|
continue
|
|
tsig_ctx = r.tsig_ctx
|
|
if not retry and query.keyring and not r.had_tsig:
|
|
raise dns.exception.FormError("missing TSIG")
|