s4-python: import a copy of the python dns library

This library is not installed on enough systems for us to rely
on it being available. We use the system copy if possible, and
fallback to this local copy

Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>

1 files changed, 428 insertions, 0 deletions

diff --git a/source4/scripting/python/samba_external/dnspython/dns/query.py b/source4/scripting/python/samba_external/dnspython/dns/query.py
new file mode 100644
index 0000000000..c023b140af
--- /dev/null
+++ b/source4/scripting/python/samba_external/dnspython/dns/query.py
@@ -0,0 +1,428 @@
+# Copyright (C) 2003-2007, 2009, 2010 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
+
+class UnexpectedSource(dns.exception.DNSException):
+    """Raised if a query response comes from an unexpected address or port."""
+    pass
+
+class BadResponse(dns.exception.FormError):
+    """Raised if a query response does not respond to the question asked."""
+    pass
+
+def _compute_expiration(timeout):
+    if timeout is None:
+        return None
+    else:
+        return time.time() + timeout
+
+def _wait_for(ir, iw, ix, 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 timeout is None:
+                (r, w, x) = select.select(ir, iw, ix)
+            else:
+                (r, w, x) = select.select(ir, iw, ix, timeout)
+        except select.error, e:
+            if e.args[0] != errno.EINTR:
+                raise e
+        done = True
+        if len(r) == 0 and len(w) == 0 and len(x) == 0:
+            raise dns.exception.Timeout
+
+def _wait_for_readable(s, expiration):
+    _wait_for([s], [], [s], expiration)
+
+def _wait_for_writable(s, expiration):
+    _wait_for([], [s], [s], 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 udp(q, where, timeout=None, port=53, af=None, source=None, source_port=0,
+        ignore_unexpected=False, one_rr_per_rrset=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 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 IPv4 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()
+    if af is None:
+        try:
+            af = dns.inet.af_for_address(where)
+        except:
+            af = dns.inet.AF_INET
+    if af == dns.inet.AF_INET:
+        destination = (where, port)
+        if source is not None:
+            source = (source, source_port)
+    elif af == dns.inet.AF_INET6:
+        destination = (where, port, 0, 0)
+        if source is not None:
+            source = (source, source_port, 0, 0)
+    s = socket.socket(af, socket.SOCK_DGRAM, 0)
+    try:
+        expiration = _compute_expiration(timeout)
+        s.setblocking(0)
+        if source is not None:
+            s.bind(source)
+        _wait_for_writable(s, expiration)
+        s.sendto(wire, destination)
+        while 1:
+            _wait_for_readable(s, expiration)
+            (wire, from_address) = s.recvfrom(65535)
+            if _addresses_equal(af, from_address, destination) or \
+                    (dns.inet.is_multicast(where) and \
+                         from_address[1:] == destination[1:]):
+                break
+            if not ignore_unexpected:
+                raise UnexpectedSource('got a response from '
+                                       '%s instead of %s' % (from_address,
+                                                             destination))
+    finally:
+        s.close()
+    r = dns.message.from_wire(wire, keyring=q.keyring, request_mac=q.mac,
+                              one_rr_per_rrset=one_rr_per_rrset)
+    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 = ''
+    while count > 0:
+        _wait_for_readable(sock, expiration)
+        n = sock.recv(count)
+        if n == '':
+            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 v[0] != errno.EINPROGRESS and \
+               v[0] != errno.EWOULDBLOCK and \
+               v[0] != 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 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 IPv4 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()
+    if af is None:
+        try:
+            af = dns.inet.af_for_address(where)
+        except:
+            af = dns.inet.AF_INET
+    if af == dns.inet.AF_INET:
+        destination = (where, port)
+        if source is not None:
+            source = (source, source_port)
+    elif af == dns.inet.AF_INET6:
+        destination = (where, port, 0, 0)
+        if source is not None:
+            source = (source, source_port, 0, 0)
+    s = socket.socket(af, socket.SOCK_STREAM, 0)
+    try:
+        expiration = _compute_expiration(timeout)
+        s.setblocking(0)
+        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:
+        s.close()
+    r = dns.message.from_wire(wire, keyring=q.keyring, request_mac=q.mac,
+                              one_rr_per_rrset=one_rr_per_rrset)
+    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.rdatatype.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 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 IPv4 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, (str, unicode)):
+        zone = dns.name.from_text(zone)
+    if isinstance(rdtype, str):
+        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 not keyring is None:
+        q.use_tsig(keyring, keyname, algorithm=keyalgorithm)
+    wire = q.to_wire()
+    if af is None:
+        try:
+            af = dns.inet.af_for_address(where)
+        except:
+            af = dns.inet.AF_INET
+    if af == dns.inet.AF_INET:
+        destination = (where, port)
+        if source is not None:
+            source = (source, source_port)
+    elif af == dns.inet.AF_INET6:
+        destination = (where, port, 0, 0)
+        if source is not None:
+            source = (source, source_port, 0, 0)
+    if use_udp:
+        if rdtype != dns.rdatatype.IXFR:
+            raise ValueError('cannot do a UDP AXFR')
+        s = socket.socket(af, socket.SOCK_DGRAM, 0)
+    else:
+        s = socket.socket(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
+    soa_rrset = None
+    soa_count = 0
+    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)
+        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=(rdtype==dns.rdatatype.IXFR))
+        tsig_ctx = r.tsig_ctx
+        first = False
+        answer_index = 0
+        delete_mode = False
+        expecting_SOA = False
+        if soa_rrset is None:
+            if not r.answer or r.answer[0].name != oname:
+                raise dns.exception.FormError
+            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 rrset == soa_rrset and not 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()