def __do_update(self):
'''Scan, check, and execute the Update section in the
DDNS Update message.
Returns an Rcode to signal the result (NOERROR upon success,
any error result otherwise).
'''
# prescan
prescan_result = self.__do_prescan()
if prescan_result != Rcode.NOERROR:
return prescan_result
# update
try:
# Do special handling for SOA first
self.__update_soa()
# Algorithm from RFC2136 Section 3.4
# Note that this works on full rrsets, not individual RRs.
# Some checks might be easier with individual RRs, but only if we
# would use the ZoneUpdater directly (so we can query the
# 'zone-as-it-would-be-so-far'. However, due to the current use
# of the Diff class, this is not the case, and therefore it
# is easier to work with full rrsets for the most parts
# (less lookups needed; conversion to individual rrs is
# the same effort whether it is done here or in the several
# do_update statements)
for rrset in self.__message.get_section(SECTION_UPDATE):
if rrset.get_class() == self.__zclass:
self.__do_update_add_rrs_to_rrset(rrset)
elif rrset.get_class() == RRClass.ANY:
if rrset.get_type() == RRType.ANY:
self.__do_update_delete_name(rrset)
else:
self.__do_update_delete_rrset(rrset)
elif rrset.get_class() == RRClass.NONE:
self.__do_update_delete_rrs_from_rrset(rrset)
if not check_zone(self.__zname, self.__zclass,
self.__diff.get_rrset_collection(),
(self.__validate_error, self.__validate_warning)):
raise UpdateError('Validation of the new zone failed',
self.__zname, self.__zclass, Rcode.REFUSED)
self.__diff.commit()
return Rcode.NOERROR
except UpdateError:
# Propagate UpdateError exceptions (don't catch them in the
# blocks below)
raise
except isc.datasrc.Error as dse:
logger.info(LIBDDNS_UPDATE_DATASRC_COMMIT_FAILED, dse)
return Rcode.SERVFAIL
except Exception as uce:
logger.error(LIBDDNS_UPDATE_UNCAUGHT_EXCEPTION,
ClientFormatter(self.__client_addr),
ZoneFormatter(self.__zname, self.__zclass),
uce)
return Rcode.SERVFAIL
def handle(self):
'''Handle the update request according to RFC2136.
This method returns a tuple of the following three elements that
indicate the result of the request.
- Result code of the request processing, which are:
UPDATE_SUCCESS Update request granted and succeeded.
UPDATE_ERROR Some error happened to be reported in the response.
UPDATE_DROP Error happened and no response should be sent.
Except the case of UPDATE_DROP, the UpdateSession object will have
created a response that is to be returned to the request client,
which can be retrieved by get_message(). If it's UPDATE_DROP,
subsequent call to get_message() returns None.
- The name of the updated zone (isc.dns.Name object) in case of
UPDATE_SUCCESS; otherwise None.
- The RR class of the updated zone (isc.dns.RRClass object) in case
of UPDATE_SUCCESS; otherwise None.
'''
try:
self._get_update_zone()
# Contrary to what RFC2136 specifies, we do ACL checks before
# prerequisites. It's now generally considered to be a bad
# idea, and actually does harm such as information
# leak. It should make more sense to prevent any security issues
# by performing ACL check as early as possible.
self.__check_update_acl(self.__zname, self.__zclass)
self._create_diff()
prereq_result = self.__check_prerequisites()
if prereq_result != Rcode.NOERROR():
self.__make_response(prereq_result)
return UPDATE_ERROR, self.__zname, self.__zclass
update_result = self.__do_update()
if update_result != Rcode.NOERROR():
self.__make_response(update_result)
return UPDATE_ERROR, self.__zname, self.__zclass
self.__make_response(Rcode.NOERROR())
return UPDATE_SUCCESS, self.__zname, self.__zclass
except UpdateError as e:
if not e.nolog:
logger.debug(logger.DBGLVL_TRACE_BASIC, LIBDDNS_UPDATE_ERROR,
ClientFormatter(self.__client_addr, self.__tsig),
ZoneFormatter(e.zname, e.zclass), e)
# If RCODE is specified, create a corresponding resonse and return
# ERROR; otherwise clear the message and return DROP.
if e.rcode is not None:
self.__make_response(e.rcode)
return UPDATE_ERROR, None, None
self.__message = None
return UPDATE_DROP, None, None
except isc.datasrc.Error as e:
logger.error(LIBDDNS_DATASRC_ERROR,
ClientFormatter(self.__client_addr, self.__tsig), e)
self.__make_response(Rcode.SERVFAIL())
return UPDATE_ERROR, None, None
def __validate_error(self, reason):
'''
Used as error callback below.
'''
logger.error(LIBDDNS_ZONE_INVALID_ERROR, self.__zname, self.__zclass,
reason)