Firewall on Demand

import nxpy as np

from ncclient import manager

from ncclient.transport.errors import AuthenticationError, SSHError

from lxml import etree as ET

from django.conf import settings

import logging

from django.core.cache import cache

FORMAT = '%(asctime)s %(levelname)s: %(message)s'

logging.basicConfig(format=FORMAT)

logger = logging.getLogger(__name__)

logger.setLevel(logging.DEBUG)

class Retriever(object):

    def __init__(self, device=settings.NETCONF_DEVICE, username=settings.NETCONF_USER, password=settings.NETCONF_PASS, filter=settings.ROUTES_FILTER, route_name=None, xml=None):

        self.device = device

        self.username = username

        self.password = password

        self.filter = filter

        self.xml = xml

        if route_name:

            self.filter = settings.ROUTE_FILTER%route_name

    def fetch_xml(self):

        with manager.connect(host=self.device, port=830, username=self.username, password=self.password) as m:

            xmlconfig = m.get_config(source='running', filter=('subtree',self.filter)).data_xml

        return xmlconfig

    def proccess_xml(self):

        if self.xml:

            xmlconfig = self.xml

        else:

            xmlconfig = self.fetch_xml()

        parser = np.Parser()

        parser.confile = xmlconfig

        device = parser.export()

        return device    

    def fetch_device(self):

        device = cache.get("device")

        if device:

            return device

        else:

            device = self.proccess_xml()

            if device.routing_options:

                cache.set("device", device, 600)

                return device

            else:

                return False

class Applier(object):

    def __init__(self, route_objects = [], route_object=None, device=settings.NETCONF_DEVICE, username=settings.NETCONF_USER, password=settings.NETCONF_PASS):

        self.route_object = route_object

        self.route_objects = route_objects

        self.device = device

        self.username = username

        self.password = password

    def to_xml(self, operation=None):

        logger.info("Operation: %s"%operation)

        if self.route_object:

            logger.info("Generating XML config")

            route_obj = self.route_object

            device = np.Device()

            flow = np.Flow()

            route = np.Route()

            flow.routes.append(route)

            device.routing_options.append(flow)

            route.name = route_obj.name

            if operation == "delete":

                logger.info("Requesting a delete operation")

                route.operation = operation

                device = device.export(netconf_config=True)

                return ET.tostring(device)

            if route_obj.source:

                route.match['source'].append(route_obj.source)

            if route_obj.destination:

                route.match['destination'].append(route_obj.destination)

            if route_obj.protocol:

                route.match['protocol'].append(route_obj.protocol)

            try:

                if route_obj.port:

                    for port in route_obj.port.all():

                        route.match['port'].append(port.port)

            except:

                pass

            try:

                if route_obj.destinationport:

                    for port in route_obj.destinationport.all():

                        route.match['destination-port'].append(port.port)

            except:

                pass

            try:

                if route_obj.sourceport:

                    for port in route_obj.sourceport.all():

                        route.match['source-port'].append(port.port)

            except:

                pass

            if route_obj.icmpcode:

                route.match['icmp-code'].append(route_obj.icmpcode)

            if route_obj.icmptype:

                route.match['icmp-type'].append(route_obj.icmptype)

            if route_obj.tcpflag:

                route.match['tcp-flags'].append(route_obj.tcpflag)

            try:

                if route_obj.dscp:

                    for dscp in route_obj.dscp.all():

                        route.match['dscp'].append(dscp.dscp)

            except:

                pass

            if route_obj.fragmenttype:

                route.match['fragment'].append(route_obj.fragmenttype)

            for thenaction in route_obj.then.all():

                if thenaction.action_value:

                    route.then[thenaction.action] = thenaction.action_value

                else:

                    route.then[thenaction.action] = True

            if operation == "replace":

                logger.info("Requesting a replace operation")

                route.operation = operation

            device = device.export(netconf_config=True)

            return ET.tostring(device)

        else:

            return False

    def delete_routes(self):

        if self.route_objects:

            logger.info("Generating XML config")

            device = np.Device()

            flow = np.Flow()

            for route_object in self.route_objects:

                route_obj = route_object

                route = np.Route()

                flow.routes.append(route)

                route.name = route_obj.name

                route.operation = 'delete'

            device.routing_options.append(flow)

            device = device.export(netconf_config=True)

            return ET.tostring(device)

        else:

            return False    

    def apply(self, configuration = None, operation=None):

        reason = None

        if not configuration:

            configuration = self.to_xml(operation=operation)

        edit_is_successful = False

        commit_confirmed_is_successful = False

        commit_is_successful = False

        if configuration:

            with manager.connect(host=self.device, port=830, username=self.username, password=self.password) as m:

                assert(":candidate" in m.server_capabilities)

                with m.locked(target='candidate'):

                    m.discard_changes()

                    try:

                        edit_response = m.edit_config(target='candidate', config=configuration, test_option='test-then-set')

                        edit_is_successful, reason = is_successful(edit_response)

                        logger.info("Successfully edited @ %s" % self.device)

                        if not edit_is_successful:

                            raise Exception()

                    except Exception as e:

                        cause="Caught edit exception: %s %s" %(e,reason)

                        cause=cause.replace('\n', '')

                        logger.error(cause)

                        m.discard_changes()

                        return False, cause

                    if edit_is_successful:

                        try:

                            commit_confirmed_response = m.commit(confirmed=True, timeout=settings.COMMIT_CONFIRMED_TIMEOUT)

                            commit_confirmed_is_successful, reason = is_successful(commit_confirmed_response)

                            if not commit_confirmed_is_successful:

                                raise Exception()

                            else:

                                logger.info("Successfully confirmed committed @ %s" % self.device)

                                if not settings.COMMIT:

                                    return True, "Successfully confirmed committed"

                        except Exception as e:

                            cause="Caught commit confirmed exception: %s %s" %(e,reason)

                            cause=cause.replace('\n', '')

                            logger.error(cause)

                            return False, cause

                        if settings.COMMIT:

                            if edit_is_successful and commit_confirmed_is_successful:

                                try:

                                    commit_response = m.commit(confirmed=False)

                                    commit_is_successful, reason = is_successful(commit_response)

                                    logger.info("Successfully committed @ %s" % self.device)

                                    newconfig = m.get_config(source='running', filter=('subtree',settings.ROUTES_FILTER)).data_xml

                                    retrieve = Retriever(xml=newconfig)

                                    cache.set("device", retrieve.proccess_xml(), 600)

                                    if not commit_is_successful:

                                        raise Exception()

                                    else:

                                        logger.info("Successfully cached device configuration")

                                        return True, "Successfully committed"

                                except Exception as e:

                                    cause="Caught commit exception: %s %s" %(e,reason)

                                    cause=cause.replace('\n', '')

                                    logger.error(cause)

                                    return False, cause

        else:

            return False, "No configuration was supplied"

def is_successful(response):

    from StringIO import StringIO

    doc = parsexml_(StringIO(response))

    rootNode = doc.getroot()

    success_list = rootNode.xpath("//*[local-name()='ok']")

    if len(success_list)>0:

        return True, None

    else:

        reason_return = ''

        reason_list = rootNode.xpath("//*[local-name()='error-message']")

        for reason in reason_list:

            reason_return = "%s %s" %(reason_return, reason.text)  

        return False, reason_return

def parsexml_(*args, **kwargs):

    if 'parser' not in kwargs:

        kwargs['parser'] = ET.ETCompatXMLParser()

    doc = ET.parse(*args, **kwargs)

    return doc