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#!/usr/bin/python
#
# Copyright 2012 Google Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Generator for DNS based network definitions."""
__author__ = 'msu@google.com (Martin Suess)'
import logging
import socket
from third_party import ipaddr
import generator
class DnsGeneratorError(Exception):
"""Exception to use when DnsGenerator fails."""
class DnsGenerator(generator.Generator):
"""Generator implementation for network definitions based on DNS."""
SUPPORTED_TYPES = ['A', 'AAAA']
def GenerateDefinition(self, config, unused_global_config):
"""Generates a list of all nodes in a network definition.
This method basically processes all the configuration which is
hierarchically below "networks" in the "definitions" section in the
configuration file to generate a list of all nodes in that definition.
Args:
config: YAML configuration structure (dictionaries, lists and strings)
representing the "networks" section in "definitions" of the
configuration file.
unused_global_config: YAML configuration structure (dictionaries, lists
and strings) representing the "global" section of the configuration
file.
Returns:
Tuples of IPNetwork objects and string comments representing all the nodes
in one definition.
Raises:
DefinateConfigError: The configuration is not well formed.
DnsGeneratorError: There is a problem generating the output.
"""
nodes = []
yaml_structure = {
'names': ['str'],
'types': ['str'],
}
for network in config:
self._yaml_validator.CheckConfiguration(network, yaml_structure)
for typ in network['types']:
if typ not in self.SUPPORTED_TYPES:
raise DnsGeneratorError('Unsupported DNS type found: %s' % typ)
for name in network['names']:
try:
addr_list = socket.getaddrinfo(name, None)
except socket.gaierror:
raise DnsGeneratorError('Hostname not found: %s' % name)
for family, _, _, _, sockaddr in addr_list:
ip_addr = None
if family == socket.AF_INET and 'A' in network['types']:
# sockaddr = (address, port)
ip_addr = ipaddr.IPv4Network(sockaddr[0])
elif family == socket.AF_INET6 and 'AAAA' in network['types']:
# sockaddr = (address, port, flow info, scope id)
ip_addr = ipaddr.IPv6Network(sockaddr[0])
else:
logging.debug('Skipping unknown AF \'%d\' for: %s', family, name)
if ip_addr:
nodes.append((ip_addr, name))
return nodes
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