initial import of rndc module

README

+RNDC Protocol Library
+
+This library implements the RNDC protocol natively in Python, to allow direct
+control of BIND instances from within your Python programs.

rndc.py

+############################################################################
+# Copyright (C) 2016  Internet Systems Consortium, Inc. ("ISC")
+#
+# Permission to use, copy, modify, and/or distribute this software 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 ISC DISCLAIMS ALL WARRANTIES WITH
+# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+# AND FITNESS.  IN NO EVENT SHALL ISC 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.
+############################################################################
+# rndc.py
+# This module implements the RNDC control protocol.
+############################################################################
+
+from collections import OrderedDict
+from exceptions import TypeError
+import time
+import struct
+import hashlib
+import hmac
+import base64
+import random
+import socket
+
+
+class rndc(object):
+    """RNDC protocol client library"""
+    __algos = {'md5':    157,
+               'sha1':   161,
+               'sha224': 162,
+               'sha256': 163,
+               'sha384': 164,
+               'sha512': 165}
+
+    def __init__(self, host, algo, secret):
+        """Creates a persistent connection to RNDC and logs in
+        host - (ip, port) tuple
+        algo - HMAC algorithm, one of md5, sha1, sha224, sha256, sha384, sha512
+        secret - HMAC secret, base64 encoded"""
+        self.host = host
+        self.algo = algo
+        self.hlalgo = getattr(hashlib, algo)
+        self.secret = base64.b64decode(secret)
+        self.ser = random.randint(0, 1 << 24)
+        self.nonce = None
+        self.__connect_login()
+
+    def call(self, cmd):
+        """Call a RNDC command, all parsing is done on the server side
+        cmd - a complete string with a command (eg 'reload zone example.com')
+        """
+        return dict(self.__command(type=cmd)['_data'])
+
+    def __serialize_dict(self, data, ignore_auth=False):
+        rv = ''
+        for k, v in data.iteritems():
+            if ignore_auth and k == '_auth':
+                continue
+            rv += chr(len(k))
+            rv += k
+            if type(v) == str:
+                rv += struct.pack('>BI', 1, len(v)) + v
+            elif type(v) == OrderedDict:
+                sd = self.__serialize_dict(v)
+                rv += struct.pack('>BI', 2, len(sd)) + sd
+            else:
+                raise NotImplementedError('Cannot serialize element of type %s'
+                                          % type(v))
+        return rv
+
+    def __prep_message(self, *args, **kwargs):
+        self.ser += 1
+        now = int(time.time())
+        data = OrderedDict(*args, **kwargs)
+
+        d = OrderedDict()
+        d['_auth'] = OrderedDict()
+        d['_ctrl'] = OrderedDict()
+        d['_ctrl']['_ser'] = str(self.ser)
+        d['_ctrl']['_tim'] = str(now)
+        d['_ctrl']['_exp'] = str(now+60)
+        if self.nonce is not None:
+            d['_ctrl']['_nonce'] = self.nonce
+        d['_data'] = data
+
+        msg = self.__serialize_dict(d, ignore_auth=True)
+        hash = hmac.new(self.secret, msg, self.hlalgo).digest()
+        bhash = base64.b64encode(hash)
+        if self.algo == 'md5':
+            d['_auth']['hmd5'] = struct.pack('22s', bhash)
+        else:
+            d['_auth']['hsha'] = struct.pack('B88s',
+                                             self.__algos[self.algo], bhash)
+        msg = self.__serialize_dict(d)
+        msg = struct.pack('>II', len(msg) + 4, 1) + msg
+        return msg
+
+    def __verify_msg(self, msg):
+        if self.nonce is not None and msg['_ctrl']['_nonce'] != self.nonce:
+            return False
+        bhash = msg['_auth']['hmd5' if self.algo == 'md5' else 'hsha']
+        bhash += '=' * (4 - (len(bhash) % 4))
+        remote_hash = base64.b64decode(bhash)
+        my_msg = self.__serialize_dict(msg, ignore_auth=True)
+        my_hash = hmac.new(self.secret, my_msg, self.hlalgo).digest()
+        return (my_hash == remote_hash)
+
+    def __command(self, *args, **kwargs):
+        msg = self.__prep_message(*args, **kwargs)
+        sent = self.socket.send(msg)
+        if sent != len(msg):
+            raise IOError("Cannot send the message")
+
+        header = self.socket.recv(8)
+        if len(header) != 8:
+            # What should we throw here? Bad auth can cause this...
+            raise IOError("Can't read response header")
+
+        length, version = struct.unpack('>II', header)
+        if version != 1:
+            raise NotImplementedError('Wrong message version %d' % version)
+
+        # it includes the header
+        length -= 4
+        data = self.socket.recv(length, socket.MSG_WAITALL)
+        if len(data) != length:
+            raise IOError("Can't read response data")
+
+        msg = self.__parse_message(data)
+        if not self.__verify_msg(msg):
+            raise IOError("Authentication failure")
+
+        return msg
+
+    def __connect_login(self):
+        self.socket = socket.create_connection(self.host)
+        self.nonce = None
+        msg = self.__command(type='null')
+        self.nonce = msg['_ctrl']['_nonce']
+
+    def __parse_element(self, input):
+        pos = 0
+        labellen = ord(input[pos])
+        pos += 1
+        label = input[pos:pos+labellen]
+        pos += labellen
+        type = ord(input[pos])
+        pos += 1
+        datalen = struct.unpack('>I', input[pos:pos+4])[0]
+        pos += 4
+        data = input[pos:pos+datalen]
+        pos += datalen
+        rest = input[pos:]
+
+        if type == 1:         # raw binary value
+            return label, data, rest
+        elif type == 2:       # dictionary
+            d = OrderedDict()
+            while len(data) > 0:
+                ilabel, value, data = self.__parse_element(data)
+                d[ilabel] = value
+            return label, d, rest
+        # TODO type 3 - list
+        else:
+            raise NotImplementedError('Unknown element type %d' % type)
+
+    def __parse_message(self, input):
+        rv = OrderedDict()
+        hdata = None
+        while len(input) > 0:
+            label, value, input = self.__parse_element(input)
+            rv[label] = value
+        return rv

setup.cfg

+[bdist_wheel]
+universal = 1

setup.py

+"""
+Pythin RNDC protocol library
+
+A native python library that implements the RNDC protocol.
+"""
+from setuptools import setup, find_packages
+
+setup(
+    name="rndc",
+    version="0.0.1",
+    description="RNDC Protocol Library",
+    long_description=__doc__,
+    keywords="library DNS RNDC BIND",
+
+    author="",
+    author_email="",
+    license="",
+
+    classifiers=[
+        'Development Status :: 4 - Beta',
+        'Intended Audience :: Developers',
+        'Natural Language :: English',
+        'Operating System :: POSIX',
+        'Operating System :: Unix',
+        'Programming Language :: Python',
+        'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3.6',
+        'Topic :: Internet :: Name Service (DNS)',
+        'Topic :: Software Development :: Libraries',
+        'Topic :: System :: Networking',
+    ],
+
+    packages=find_packages(),
+    install_requires=[],
+
+)