--- /dev/null
+# 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()
git.samba.org / samba.git / blobdiff