FM / dns

/usr/lib/python3.6/site-packages/dns

Name	Size	Mode	Actions
rdtypes/	-	0755	rm
__pycache__/	-	0755	rm
dnssec.py	14791	0644	edit dl rm
e164.py	3147	0644	edit dl rm
edns.py	4384	0644	edit dl rm
entropy.py	4465	0644	edit dl rm
exception.py	4626	0644	edit dl rm
flags.py	2664	0644	edit dl rm
grange.py	1973	0644	edit dl rm
hash.py	1100	0644	edit dl rm
inet.py	3242	0644	edit dl rm
ipv4.py	2031	0644	edit dl rm
ipv6.py	5293	0644	edit dl rm
message.py	43129	0644	edit dl rm
name.py	29425	0644	edit dl rm
namedict.py	3677	0644	edit dl rm
node.py	6056	0644	edit dl rm
opcode.py	2538	0644	edit dl rm
query.py	19645	0644	edit dl rm
rcode.py	3104	0644	edit dl rm
rdata.py	14997	0644	edit dl rm
rdataclass.py	3258	0644	edit dl rm
rdataset.py	11556	0644	edit dl rm
rdatatype.py	5339	0644	edit dl rm
renderer.py	11923	0644	edit dl rm
resolver.py	52105	0644	edit dl rm
reversename.py	3311	0644	edit dl rm
rrset.py	5995	0644	edit dl rm
set.py	7715	0644	edit dl rm
tokenizer.py	18313	0644	edit dl rm
tsig.py	7718	0644	edit dl rm
tsigkeyring.py	1737	0644	edit dl rm
ttl.py	2283	0644	edit dl rm
update.py	10012	0644	edit dl rm
version.py	1258	0644	edit dl rm
wiredata.py	3731	0644	edit dl rm
zone.py	40026	0644	edit dl rm
_compat.py	1313	0644	edit dl rm
__init__.py	1327	0644	edit dl rm

Edit: /usr/lib/python3.6/site-packages/dns/query.py (19645B)

# 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.

"""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.rdataclass
import dns.rdatatype
from ._compat import long, string_types

if sys.version_info > (3,):
    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."""

def _compute_expiration(timeout):
    if timeout is None:
        return None
    else:
        return time.time() + timeout

def _poll_for(fd, readable, writable, error, timeout):
    """Poll polling backend.
    @param fd: File descriptor
    @type fd: int
    @param readable: Whether to wait for readability
    @type readable: bool
    @param writable: Whether to wait for writability
    @type writable: bool
    @param timeout: Deadline timeout (expiration time, in seconds)
    @type timeout: float
    @return True on success, False on timeout
    """
    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.
    @param fd: File descriptor
    @type fd: int
    @param readable: Whether to wait for readability
    @type readable: bool
    @param writable: Whether to wait for writability
    @type writable: bool
    @param timeout: Deadline timeout (expiration time, in seconds)
    @type timeout: float
    @return True on success, False on timeout
    """
    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):
    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
    n1 = dns.inet.inet_pton(af, a1[0])
    n2 = dns.inet.inet_pton(af, a2[0])
    return n1 == n2 and a1[1:] == a2[1:]

def _matches_destination(af, from_address, destination, ignore_unexpected):
    # Check that from_address is appropriate for a response to a query
    # sent to destination.
    if not destination:
        return True
    if _addresses_equal(af, from_address, destination) or (
        dns.inet.is_multicast(destination[0]) and from_address[1:] == destination[1:]
    ):
        return True
    elif ignore_unexpected:
        return False
    raise UnexpectedSource(
        f"got a response from {from_address} instead of " f"{destination}"
    )

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 udp(q, where, timeout=None, port=53, af=None, source=None, source_port=0,
        ignore_unexpected=False, one_rr_per_rrset=False, ignore_errors=False):
    """Return the response obtained after sending a query via UDP.

@param q: the query
    @type q: dns.message.Message
    @param where: where to send the message
    @type where: string containing an IPv4 or IPv6 address
    @param timeout: The number of seconds to wait before the query times out.
    If None, the default, wait forever.
    @type timeout: float
    @param port: The port to which to send the message.  The default is 53.
    @type port: int
    @param af: 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.
    @type af: int
    @rtype: dns.message.Message object
    @param source: source address.  The default is the wildcard address.
    @type source: string
    @param source_port: The port from which to send the message.
    The default is 0.
    @type source_port: int
    @param ignore_unexpected: If True, ignore responses from unexpected
    sources.  The default is False.
    @type ignore_unexpected: bool
    @param one_rr_per_rrset: Put each RR into its own RRset
    @type one_rr_per_rrset: bool
    """

wire = q.to_wire()
    (af, destination, source) = _destination_and_source(af, where, port,
                                                        source, source_port)
    s = socket_factory(af, socket.SOCK_DGRAM, 0)
    begin_time = None
    try:
        expiration = _compute_expiration(timeout)
        s.setblocking(0)
        if source is not None:
            s.bind(source)
        _wait_for_writable(s, expiration)
        begin_time = time.time()
        s.sendto(wire, destination)
        while 1:
            _wait_for_readable(s, expiration)
            (wire, from_address) = s.recvfrom(65535)
            if not _matches_destination(
                s.family, from_address, destination, ignore_unexpected
            ):
                continue

response_time = time.time() - begin_time

try:
                r = dns.message.from_wire(wire, keyring=q.keyring, request_mac=q.mac,
                                  one_rr_per_rrset=one_rr_per_rrset)
                r.time = response_time
            except Exception:
                if ignore_errors:
                    continue
                else:
                    raise

if q.is_response(r):
                return r
            else:
                if ignore_errors:
                    continue
                else:
                    raise BadResponse
    finally:
        s.close()

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 _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):
    """Return the response obtained after sending a query via TCP.

@param q: the query
    @type q: dns.message.Message object
    @param where: where to send the message
    @type where: string containing an IPv4 or IPv6 address
    @param timeout: The number of seconds to wait before the query times out.
    If None, the default, wait forever.
    @type timeout: float
    @param port: The port to which to send the message.  The default is 53.
    @type port: int
    @param af: 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.
    @type af: int
    @rtype: dns.message.Message object
    @param source: source address.  The default is the wildcard address.
    @type source: string
    @param source_port: The port from which to send the message.
    The default is 0.
    @type source_port: int
    @param one_rr_per_rrset: Put each RR into its own RRset
    @type one_rr_per_rrset: bool
    """

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
    try:
        expiration = _compute_expiration(timeout)
        s.setblocking(0)
        begin_time = time.time()
        if source is not None:
            s.bind(source)
        _connect(s, destination)

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
        _net_write(s, tcpmsg, expiration)
        ldata = _net_read(s, 2, expiration)
        (l,) = struct.unpack("!H", ldata)
        wire = _net_read(s, l, expiration)
    finally:
        if begin_time is None:
            response_time = 0
        else:
            response_time = time.time() - begin_time
        s.close()
    r = dns.message.from_wire(wire, keyring=q.keyring, request_mac=q.mac,
                              one_rr_per_rrset=one_rr_per_rrset)
    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.

@param where: where to send the message
    @type where: string containing an IPv4 or IPv6 address
    @param zone: The name of the zone to transfer
    @type zone: dns.name.Name object or string
    @param rdtype: The type of zone transfer.  The default is
    dns.rdatatype.AXFR.
    @type rdtype: int or string
    @param rdclass: The class of the zone transfer.  The default is
    dns.rdataclass.IN.
    @type rdclass: int or string
    @param timeout: The number of seconds to wait for each response message.
    If None, the default, wait forever.
    @type timeout: float
    @param port: The port to which to send the message.  The default is 53.
    @type port: int
    @param keyring: The TSIG keyring to use
    @type keyring: dict
    @param keyname: The name of the TSIG key to use
    @type keyname: dns.name.Name object or string
    @param relativize: 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().
    @type relativize: bool
    @param af: 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.
    @type af: int
    @param lifetime: 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.
    @type lifetime: float
    @rtype: generator of dns.message.Message objects.
    @param source: source address.  The default is the wildcard address.
    @type source: string
    @param source_port: The port from which to send the message.
    The default is 0.
    @type source_port: int
    @param serial: The SOA serial number to use as the base for an IXFR diff
    sequence (only meaningful if rdtype == dns.rdatatype.IXFR).
    @type serial: int
    @param use_udp: Use UDP (only meaningful for IXFR)
    @type use_udp: bool
    @param keyalgorithm: The TSIG algorithm to use; defaults to
    dns.tsig.default_algorithm
    @type keyalgorithm: string
    """

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 \
           (expiration is not None and 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)
        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()

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