Пример #1
0
    def __init__(self, id, config_file, policy_file, logger):
        # participant id
        self.id = id
        self.logger = logger

        # used to signal termination
        self.run = True
        self.prefix_lock = {}

        # Initialize participant params
        self.cfg = PConfig(config_file, self.id)

        # load policies
        self.policies = self.load_policies(policy_file)

        # The port 0 MAC is used for tagging outbound rules as belonging to us
        self.port0_mac = self.cfg.port0_mac

        self.nexthop_2_part = self.cfg.get_nexthop_2_part()

        # VNHs related params
        self.num_VNHs_in_use = 0
        self.VNH_2_vmac = {}
        self.vmac_2_VNH = {}
        self.FEC_list = {}
        self.prefix_2_FEC = {}
        self.prefix_2_VNH_nrfp = {}
        #SWIFT Backup equivalence class
        self.BEC_list = {((-1, -1, -1), (-1, -1, -1)): {'id': 1, 'as_path': None, 'backup_nbs': None, 'as_path_vmac': None}}
        self.prefix_2_BEC = {}
        self.BECid_FECid_2_VNH = {}
        self.prefix_2_BEC_nrfp = {}
        self.max_depth = self.cfg.Swift_vmac["max_depth"]
        self.nexthops_nb_bits = self.cfg.Swift_vmac["nexthops_nb_bits"]
        self.Swift_flow_rule_timeout = self.cfg.Swift_vmac["hard timeout"]
        self.vnh_2_BFEC = {}
        #swift tag dic mapping ip to mac
        self.tag_dict = {}
        self.prefix_2_FEC_nrfp = {}
        self.prefix_2_BEC_nrfp = {}

        # Superset related params
        if self.cfg.isSupersetsMode():
            self.supersets = SuperSets(self, self.cfg.vmac_options)

        # Keep track of flow rules pushed
        self.dp_pushed = []
        # Keep track of flow rules which are scheduled to be pushed
        self.dp_queued = []
Пример #2
0
    def __init__(self, pid, config_file, policy_file, rib_file, logger, asn_2_id, prefrns):
        # participant id
        self.id = pid
        # print ID for logging
        self.route_id = 0
        self.end_time = 0
        self.logger = logger

        # used to signal termination
        self.run = True
        self.prefix_lock = {}

        # Initialize participant params
        self.cfg = PConfig(config_file, self.id)
        # Vmac encoding mode
        # self.cfg.vmac_mode = config_file["vmac_mode"]
        # Dataplane mode---multi table or multi switch
        # self.cfg.dp_mode = config_file["dp_mode"]

        # ExaBGP Peering Instance
        self.bgp_instance = self.cfg.get_bgp_instance()
        self.bgp_instance.init(asn_2_id, prefrns, rib_file)

        self.policies = self.load_policies(policy_file)

        # The port 0 MAC is used for tagging outbound rules as belonging to us
        self.port0_mac = self.cfg.port0_mac

        self.nexthop_2_part = self.cfg.get_nexthop_2_part()

        # VNHs related params
        self.num_VNHs_in_use = 0
        self.VNH_2_prefix = {}
        self.prefix_2_VNH = {}


        # Superset related params
        if self.cfg.isSupersetsMode():
            self.supersets = SuperSets(self, self.cfg.vmac_options)
        else:
            # TODO: create similar class and variables for MDS
            self.mds = None

        # Keep track of flow rules pushed
        self.dp_pushed = []
        # Keep track of flow rules which are scheduled to be pushed
        self.dp_queued = []
Пример #3
0
    def __init__(self, id, config_file, policy_file, logger):
        # participant id
        self.id = id
        # print ID for logging
        self.logger = logger

        # used to signal termination
        self.run = True
        self.prefix_lock = {}

        # Initialize participant params
        self.cfg = PConfig(config_file, self.id)
        # Vmac encoding mode
        # self.cfg.vmac_mode = config_file["vmac_mode"]
        # Dataplane mode---multi table or multi switch
        # self.cfg.dp_mode = config_file["dp_mode"]


        self.load_policies(policy_file)

        # The port 0 MAC is used for tagging outbound rules as belonging to us
        self.port0_mac = self.cfg.port0_mac

        self.nexthop_2_part = self.cfg.get_nexthop_2_part()

        # VNHs related params
        self.num_VNHs_in_use = 0
        self.VNH_2_prefix = {}
        self.prefix_2_VNH = {}


        # Superset related params
        if self.cfg.isSupersetsMode():
            self.supersets = SuperSets(self, self.cfg.vmac_options)
        else:
            # TODO: create similar class and variables for MDS
            self.mds = None

        # Keep track of flow rules pushed
        self.dp_pushed = []
        # Keep track of flow rules which are scheduled to be pushed
        self.dp_queued = []
Пример #4
0
class ParticipantController(object):
    def __init__(self, id, config_file, policy_file, logger):
        # participant id
        self.id = id
        # print ID for logging
        self.logger = logger

        # used to signal termination
        self.run = True
        self.prefix_lock = {}

        # Initialize participant params
        self.cfg = PConfig(config_file, self.id)
        # Vmac encoding mode
        # self.cfg.vmac_mode = config_file["vmac_mode"]
        # Dataplane mode---multi table or multi switch
        # self.cfg.dp_mode = config_file["dp_mode"]

        self.policies = self.load_policies(policy_file)

        # The port 0 MAC is used for tagging outbound rules as belonging to us
        self.port0_mac = self.cfg.port0_mac

        self.nexthop_2_part = self.cfg.get_nexthop_2_part()

        # VNHs related params
        self.num_VNHs_in_use = 0
        self.VNH_2_prefix = {}
        self.prefix_2_VNH = {}

        # Superset related params
        if self.cfg.isSupersetsMode():
            self.supersets = SuperSets(self, self.cfg.vmac_options)
        else:
            # TODO: create similar class and variables for MDS
            self.mds = None

        # Keep track of flow rules pushed
        self.dp_pushed = []
        # Keep track of flow rules which are scheduled to be pushed
        self.dp_queued = []

    def xstart(self):
        # Start all clients/listeners/whatevs
        self.logger.info("Starting controller for participant")

        # ExaBGP Peering Instance
        self.bgp_instance = self.cfg.get_bgp_instance()

        # Route server client, Reference monitor client, Arp Proxy client
        self.xrs_client = self.cfg.get_xrs_client(self.logger)
        self.xrs_client.send({
            'msgType': 'hello',
            'id': self.cfg.id,
            'peers_in': self.cfg.peers_in,
            'peers_out': self.cfg.peers_out,
            'ports': self.cfg.get_ports()
        })

        self.arp_client = self.cfg.get_arp_client(self.logger)
        self.arp_client.send({'msgType': 'hello', 'macs': self.cfg.get_macs()})

        # Participant Server for dynamic route updates
        self.participant_server = self.cfg.get_participant_server(
            self.id, self.logger)
        if self.participant_server is not None:
            self.participant_server.start(self)

        self.refmon_client = self.cfg.get_refmon_client(self.logger)

        # Send flow rules for initial policies to the SDX's Reference Monitor
        self.initialize_dataplane()
        self.push_dp()

        # Start the event handlers
        ps_thread_arp = Thread(target=self.start_eh_arp)
        ps_thread_arp.daemon = True
        ps_thread_arp.start()

        ps_thread_xrs = Thread(target=self.start_eh_xrs)
        ps_thread_xrs.daemon = True
        ps_thread_xrs.start()

        ps_thread_arp.join()
        ps_thread_xrs.join()
        self.logger.debug("Return from ps_thread.join()")

    def sanitize_policies(self, policies):

        port_count = len(self.cfg.ports)

        # sanitize the inbound policies
        if 'inbound' in policies:
            for policy in policies['inbound']:
                if 'action' not in policy:
                    continue
                if 'fwd' in policy['action'] and int(
                        policy['action']['fwd']) >= port_count:
                    policy['action']['fwd'] = 0
                    self.logger.warn(
                        'Port count in inbound policy is too big.  Setting it to 0.'
                    )

        # sanitize the outbound policies
        if 'outbound' in policies:
            for policy in policies['outbound']:
                # If no cookie field, give it cookie 0. (Should be OK for multiple flows with same cookie,
                # though they can't be individually removed.  TODO: THIS SHOULD BE VERIFIED)
                if 'cookie' not in policy:
                    policy['cookie'] = 0
                    self.logger.warn(
                        'Cookie not specified in new policy.  Defaulting to 0.'
                    )

        return policies

    def load_policies(self, policy_file):
        # Load policies from file

        with open(policy_file, 'r') as f:
            policies = json.load(f)

        return self.sanitize_policies(policies)

    def initialize_dataplane(self):
        "Read the config file and update the queued policy variable"

        self.logger.info("Initializing inbound rules")

        final_switch = "main-in"
        if self.cfg.isMultiTableMode():
            final_switch = "main-out"

        self.init_vnh_assignment()

        rule_msgs = init_inbound_rules(self.id, self.policies, self.supersets,
                                       final_switch)
        self.logger.debug("Rule Messages INBOUND:: " + json.dumps(rule_msgs))

        rule_msgs2 = init_outbound_rules(self, self.id, self.policies,
                                         self.supersets, final_switch)
        self.logger.debug("Rule Messages OUTBOUND:: " + json.dumps(rule_msgs2))

        if 'changes' in rule_msgs2:
            if 'changes' not in rule_msgs:
                rule_msgs['changes'] = []
            rule_msgs['changes'] += rule_msgs2['changes']

        #TODO: Initialize Outbound Policies from RIB
        self.logger.debug("Rule Messages:: " + json.dumps(rule_msgs))
        if 'changes' in rule_msgs:
            self.dp_queued.extend(rule_msgs["changes"])

    def push_dp(self):
        '''
        (1) Check if there are any policies queued to be pushed
        (2) Send the queued policies to reference monitor
        '''

        self.logger.debug("Pushing current flow mod queue:")

        # it is crucial that dp_queued is traversed chronologically
        fm_builder = FlowModMsgBuilder(self.id, self.refmon_client.key)
        for flowmod in self.dp_queued:
            self.logger.debug("MOD: " + str(flowmod))
            if (flowmod['mod_type'] == 'remove'):
                fm_builder.delete_flow_mod(flowmod['mod_type'],
                                           flowmod['rule_type'],
                                           flowmod['cookie'][0],
                                           flowmod['cookie'][1])
            elif (flowmod['mod_type'] == 'insert'):
                fm_builder.add_flow_mod(**flowmod)
            else:
                self.logger.error("Unhandled flow type: " +
                                  flowmod['mod_type'])
                continue
            self.dp_pushed.append(flowmod)

        self.dp_queued = []
        self.refmon_client.send(json.dumps(fm_builder.get_msg()))

    def stop(self):
        "Stop the Participants' SDN Controller"

        self.logger.info("Stopping Controller.")

        # Signal Termination and close blocking listener
        self.run = False

        # TODO: confirm that this isn't silly
        #self.refmon_client = None

    def start_eh_arp(self):
        self.logger.info("ARP Event Handler started.")

        while self.run:
            # need to poll since recv() will not detect close from this end
            # and need some way to shutdown gracefully.
            if not self.arp_client.poll(1):
                continue
            try:
                tmp = self.arp_client.recv()
            except EOFError:
                break

            data = json.loads(tmp)
            self.logger.debug("ARP Event received: %s", data)

            # Starting a thread for independently processing each incoming network event
            event_processor_thread = Thread(target=self.process_event,
                                            args=(data, ))
            event_processor_thread.daemon = True
            event_processor_thread.start()

        self.arp_client.close()
        self.logger.debug("Exiting start_eh_arp")

    def start_eh_xrs(self):
        self.logger.info("XRS Event Handler started.")

        while self.run:
            # need to poll since recv() will not detect close from this end
            # and need some way to shutdown gracefully.
            if not self.xrs_client.poll(1):
                continue
            try:
                tmp = self.xrs_client.recv()
            except EOFError:
                break

            data = json.loads(tmp)
            self.logger.debug("XRS Event received: %s", json.dumps(data))

            self.process_event(data)

        self.xrs_client.close()
        self.logger.debug("Exiting start_eh_xrs")

    def process_event(self, data):
        "Locally process each incoming network event"

        if 'bgp' in data:
            self.logger.debug("Event Received: BGP Update.")
            route = data['bgp']
            # Process the incoming BGP updates from XRS
            #self.logger.debug("BGP Route received: "+str(route)+" "+str(type(route)))
            self.process_bgp_route(route)

        elif 'policy' in data:
            # Process the event requesting change of participants' policies
            self.logger.debug("Event Received: Policy change.")
            change_info = data['policy']
            self.process_policy_changes(change_info)

        elif 'arp' in data:
            (requester_srcmac, requested_vnh) = tuple(data['arp'])
            self.logger.debug("Event Received: ARP request for IP " +
                              str(requested_vnh))
            self.process_arp_request(requester_srcmac, requested_vnh)

        else:
            self.logger.warn("UNKNOWN EVENT TYPE RECEIVED: " + str(data))

    def update_policies(self, new_policies, in_out):
        if in_out != 'inbound' and in_out != 'outbound':
            self.logger.exception("Illegal argument to update_policies: " +
                                  in_out)
            raise
        if in_out not in new_policies:
            return
        if in_out not in self.policies:
            self.policies[in_out] = []
        new_cookies = {
            x['cookie']
            for x in new_policies[in_out] if 'cookie' in x
        }
        self.logger.debug('new_cookies: ' + str(new_cookies))

        # remove any items with same cookie (TODO: verify that this is the behavior we want)
        self.policies[in_out] = [
            x for x in self.policies[in_out] if x['cookie'] not in new_cookies
        ]
        self.logger.debug('new_policies[io]: ' + str(new_policies[in_out]))
        self.policies[in_out].extend(new_policies[in_out])

    # Remove polices that match the cookies and return the list of cookies for removed policies
    def remove_policies_by_cookies(self, cookies, in_out):
        if in_out != 'inbound' and in_out != 'outbound':
            self.logger.exception("Illegal argument to update_policies: " +
                                  in_out)
            raise
        if in_out in self.policies:
            to_remove = [
                x['cookie'] for x in self.policies[in_out]
                if x['cookie'] in cookies
            ]
            self.policies[in_out] = [
                x for x in self.policies[in_out] if x['cookie'] not in cookies
            ]
            self.logger.debug('removed cookies: ' + str(to_remove) +
                              ' from: ' + in_out)
            return to_remove
        return []

    def queue_flow_removals(self, cookies, in_out):
        removal_msgs = []
        for cookie in cookies:
            mod = {
                "rule_type": in_out,
                "cookie": (cookie, 2**16 - 1),
                "mod_type": "remove"
            }
            removal_msgs.append(mod)
        self.logger.debug('queue_flow_removals: ' + str(removal_msgs))
        self.dp_queued.extend(removal_msgs)

    def process_policy_changes(self, change_info):
        if not self.cfg.isSupersetsMode():
            self.logger.warn(
                'Dynamic policy updates only supported in SuperSet mode')
            return

        # First step towards a less brute force approach: Handle removals without having to remove everything
        if 'removal_cookies' in change_info:
            cookies = change_info['removal_cookies']
            removed_in_cookies = self.remove_policies_by_cookies(
                cookies, 'inbound')
            self.queue_flow_removals(removed_in_cookies, 'inbound')
            removed_out_cookies = self.remove_policies_by_cookies(
                cookies, 'outbound')
            self.queue_flow_removals(removed_out_cookies, 'outbound')
            if not 'new_policies' in change_info:
                self.push_dp()
                return

        # Remainder of this method is brute force approach: wipe everything and re-do it
        # This should be replaced by a more fine grained approach
        self.logger.debug("Wiping outbound rules.")
        wipe_msgs = msg_clear_all_outbound(self.policies, self.port0_mac)
        self.dp_queued.extend(wipe_msgs)

        self.logger.debug("pre-updated policies: " + json.dumps(self.policies))
        if 'removal_cookies' in change_info:
            cookies = change_info['removal_cookies']
            self.remove_policies_by_cookies(cookies, 'inbound')
            self.remove_policies_by_cookies(cookies, 'outbound')

        if 'new_policies' in change_info:
            new_policies = change_info['new_policies']
            self.sanitize_policies(new_policies)
            self.update_policies(new_policies, 'inbound')
            self.update_policies(new_policies, 'outbound')

        self.logger.debug("updated policies: " + json.dumps(self.policies))
        self.logger.debug("pre-recomputed supersets: " +
                          json.dumps(self.supersets.supersets))

        self.initialize_dataplane()
        self.push_dp()

        # Send gratuitous ARP responses for all
        garp_required_vnhs = self.VNH_2_prefix.keys()
        for vnh in garp_required_vnhs:
            self.process_arp_request(None, vnh)

        return

        # Original code below...

        "Process the changes in participants' policies"
        # TODO: Implement the logic of dynamically changing participants' outbound and inbound policy
        '''
            change_info =
            {
                'removal_cookies' : [cookie1, ...], # Cookies of deleted policies
                'new_policies' :
                {
                    <policy file format>
                }

            }
        '''
        # remove flow rules for the old policies
        removal_msgs = []
        '''
        for cookie in change_info['removal_cookies']:
            mod =  {"rule_type":"outbound", "priority":0,
                    "match":match_args , "action":{},
                    "cookie":cookie, "mod_type":"remove"}
            removal_msgs.append(mod)
        '''

        self.dp_queued.extend(removal_msgs)

        # add flow rules for the new policies
        if self.cfg.isSupersetsMode():
            dp_msgs = ss_process_policy_change(self.supersets, add_policies,
                                               remove_policies, policies,
                                               self.port_count, self.port0_mac)
        else:
            dp_msgs = []

        self.dp_queued.extend(dp_msgs)

        self.push_dp()

        return 0

    def process_arp_request(self, part_mac, vnh):
        vmac = ""
        if self.cfg.isSupersetsMode():
            vmac = self.supersets.get_vmac(self, vnh)
        else:
            vmac = "whoa"  # MDS vmac goes here

        arp_responses = list()

        # if this is gratuitous, send a reply to the part's ID
        if part_mac is None:
            gratuitous = True
            # set fields appropriately for gratuitous arps
            i = 0
            for port in self.cfg.ports:
                eth_dst = vmac_part_port_match(self.id, i, self.supersets,
                                               False)
                arp_responses.append({
                    'SPA': vnh,
                    'TPA': vnh,
                    'SHA': vmac,
                    'THA': vmac,
                    'eth_src': vmac,
                    'eth_dst': eth_dst
                })
                i += 1

        else:  # if it wasn't gratuitous
            gratuitous = False
            # dig up the IP of the target participant
            for port in self.cfg.ports:
                if part_mac == port["MAC"]:
                    part_ip = port["IP"]
                    break

            # set field appropriately for arp responses
            arp_responses.append({
                'SPA': vnh,
                'TPA': part_ip,
                'SHA': vmac,
                'THA': part_mac,
                'eth_src': vmac,
                'eth_dst': part_mac
            })

        if gratuitous:
            self.logger.debug("Sending Gratuitious ARP: " + str(arp_responses))
        else:
            self.logger.debug("Sending ARP Response: " + str(arp_responses))

        for arp_response in arp_responses:
            arp_response['msgType'] = 'garp'
            self.arp_client.send(arp_response)

    def getlock(self, prefixes):
        prefixes.sort()
        hsh = "-".join(prefixes)
        if hsh not in self.prefix_lock:
            #self.logger.debug("First Lock:: "+str(hsh))
            self.prefix_lock[hsh] = RLock()
        #else:
        #self.logger.debug("Repeat :: "+str(hsh))
        return self.prefix_lock[hsh]

    def process_bgp_route(self, route):
        "Process each incoming BGP advertisement"
        tstart = time.time()

        # Map to update for each prefix in the route advertisement.
        updates = self.bgp_instance.update(route)
        #self.logger.debug("process_bgp_route:: "+str(updates))
        # TODO: This step should be parallelized
        # TODO: The decision process for these prefixes is going to be same, we
        # should think about getting rid of such redundant computations.
        for update in updates:
            self.bgp_instance.decision_process_local(update)
            self.vnh_assignment(update)

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.debug("Time taken for decision process: " +
                              str(elapsed))
            tstart = time.time()

        if self.cfg.isSupersetsMode():
            ################## SUPERSET RESPONSE TO BGP ##################
            # update supersets
            "Map the set of BGP updates to a list of superset expansions."
            ss_changes, ss_changed_prefs = self.supersets.update_supersets(
                self, updates)

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken to update supersets: " +
                                  str(elapsed))
                tstart = time.time()

            # ss_changed_prefs are prefixes for which the VMAC bits have changed
            # these prefixes must have gratuitous arps sent
            garp_required_vnhs = [
                self.prefix_2_VNH[prefix] for prefix in ss_changed_prefs
            ]

            "If a recomputation event was needed, wipe out the flow rules."
            if ss_changes["type"] == "new":
                self.logger.debug("Wiping outbound rules.")
                wipe_msgs = msg_clear_all_outbound(self.policies,
                                                   self.port0_mac)
                self.dp_queued.extend(wipe_msgs)

                #if a recomputation was needed, all VMACs must be reARPed
                # TODO: confirm reARPed is a word
                garp_required_vnhs = self.VNH_2_prefix.keys()

            if len(ss_changes['changes']) > 0:

                self.logger.debug("Supersets have changed: " + str(ss_changes))

                "Map the superset changes to a list of new flow rules."
                flow_msgs = update_outbound_rules(ss_changes, self.policies,
                                                  self.supersets,
                                                  self.port0_mac)

                self.logger.debug("Flow msgs: " + str(flow_msgs))
                "Dump the new rules into the dataplane queue."
                self.dp_queued.extend(flow_msgs)

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken to deal with ss_changes: " +
                                  str(elapsed))
                tstart = time.time()

        ################## END SUPERSET RESPONSE ##################

        else:
            # TODO: similar logic for MDS
            self.logger.debug("Creating ctrlr messages for MDS scheme")

        self.push_dp()

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.debug("Time taken to push dp msgs: " + str(elapsed))
            tstart = time.time()

        changed_vnhs, announcements = self.bgp_instance.bgp_update_peers(
            updates, self.prefix_2_VNH, self.cfg.ports)
        """ Combine the VNHs which have changed BGP default routes with the
            VNHs which have changed supersets.
        """

        changed_vnhs = set(changed_vnhs)
        changed_vnhs.update(garp_required_vnhs)

        # Send gratuitous ARP responses for all them
        for vnh in changed_vnhs:
            self.process_arp_request(None, vnh)

        # Tell Route Server that it needs to announce these routes
        for announcement in announcements:
            # TODO: Complete the logic for this function
            self.send_announcement(announcement)

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.debug("Time taken to send garps/announcements: " +
                              str(elapsed))
            tstart = time.time()

    def send_announcement(self, announcement):
        "Send the announcements to XRS"
        self.logger.debug("Sending announcements to XRS: %s", announcement)
        self.xrs_client.send({'msgType': 'bgp', 'announcement': announcement})

    def vnh_assignment(self, update):
        "Assign VNHs for the advertised prefixes"
        if self.cfg.isSupersetsMode():
            " Superset"
            # TODO: Do we really need to assign a VNH for each advertised prefix?
            if ('announce' in update):
                prefix = update['announce'].prefix

                if (prefix not in self.prefix_2_VNH):
                    # get next VNH and assign it the prefix
                    self.num_VNHs_in_use += 1
                    vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])

                    self.prefix_2_VNH[prefix] = vnh
                    self.VNH_2_prefix[vnh] = prefix
        else:
            "Disjoint"
            # TODO: @Robert: Place your logic here for VNH assignment for MDS scheme
            self.logger.debug("VNH assignment called for disjoint vmac_mode")

    def init_vnh_assignment(self):
        "Assign VNHs for the advertised prefixes"
        if self.cfg.isSupersetsMode():
            " Superset"
            # TODO: Do we really need to assign a VNH for each advertised prefix?
            #self.bgp_instance.rib["local"].dump()
            prefixes = self.bgp_instance.rib["local"].get_prefixes()
            #print 'init_vnh_assignment: prefixes:', prefixes
            #print 'init_vnh_assignment: prefix_2_VNH:', self.prefix_2_VNH
            for prefix in prefixes:
                if (prefix not in self.prefix_2_VNH):
                    # get next VNH and assign it the prefix
                    self.num_VNHs_in_use += 1
                    vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])

                    self.prefix_2_VNH[prefix] = vnh
                    self.VNH_2_prefix[vnh] = prefix
        else:
            "Disjoint"
            # TODO: @Robert: Place your logic here for VNH assignment for MDS scheme
            self.logger.debug("VNH assignment called for disjoint vmac_mode")
Пример #5
0
class ParticipantController(object):
    def __init__(self, id, config_file, policy_file, logger):
        # participant id
        self.id = id
        # print ID for logging
        self.logger = logger

        # used to signal termination
        self.run = True
        self.prefix_lock = {}

        # Initialize participant params
        self.cfg = PConfig(config_file, self.id)
        # Vmac encoding mode
        # self.cfg.vmac_mode = config_file["vmac_mode"]
        # Dataplane mode---multi table or multi switch
        # self.cfg.dp_mode = config_file["dp_mode"]


        self.load_policies(policy_file)

        # The port 0 MAC is used for tagging outbound rules as belonging to us
        self.port0_mac = self.cfg.port0_mac

        self.nexthop_2_part = self.cfg.get_nexthop_2_part()

        # VNHs related params
        self.num_VNHs_in_use = 0
        self.VNH_2_prefix = {}
        self.prefix_2_VNH = {}


        # Superset related params
        if self.cfg.isSupersetsMode():
            self.supersets = SuperSets(self, self.cfg.vmac_options)
        else:
            # TODO: create similar class and variables for MDS
            self.mds = None

        # Keep track of flow rules pushed
        self.dp_pushed = []
        # Keep track of flow rules which are scheduled to be pushed
        self.dp_queued = []


    def start(self):
        # Start all clients/listeners/whatevs
        self.logger.info("Starting controller for participant")

        # ExaBGP Peering Instance
        self.bgp_instance = self.cfg.get_bgp_instance()
        self.logger.debug("Trace: Started controller for participant")

        # Route server client, Reference monitor client, Arp Proxy client
        self.xrs_client = self.cfg.get_xrs_client(self.logger)
        self.arp_client = self.cfg.get_arp_client(self.logger)
        self.refmon_client = self.cfg.get_refmon_client(self.logger)
         # class for building flow mod msgs to the reference monitor
        self.fm_builder = FlowModMsgBuilder(self.id, self.refmon_client.key)

        # Send flow rules for initial policies to the SDX's Reference Monitor
        self.initialize_dataplane()
        self.push_dp()

        # Start the event handler
        eh_socket = self.cfg.get_eh_info()
        self.listener_eh = Listener(eh_socket, authkey=None)
        self.start_eh()
        #ps_thread = Thread(target=self.start_eh)
        #ps_thread.daemon = True
        #ps_thread.start()


    def load_policies(self, policy_file):
        # Load policies from file

        with open(policy_file, 'r') as f:
            self.policies = json.load(f)

        port_count = len(self.cfg.ports)

        # sanitize the input policies
        if 'inbound' in self.policies:
            for policy in self.policies['inbound']:
                if 'action' not in policy:
                    continue
                if 'fwd' in policy['action'] and int(policy['action']['fwd']) >= port_count:
                    policy['action']['fwd'] = 0


    def initialize_dataplane(self):
        "Read the config file and update the queued policy variable"

        self.logger.info("Initializing inbound rules")

        final_switch = "main-in"
        if self.cfg.isMultiTableMode():
            final_switch = "main-out"

        self.init_vnh_assignment()

        rule_msgs = init_inbound_rules(self.id, self.policies,
                                        self.supersets, final_switch)
        self.logger.debug("Rule Messages INBOUND:: "+str(rule_msgs))

        rule_msgs2 = init_outbound_rules(self, self.id, self.policies,
                                        self.supersets, final_switch)
        self.logger.debug("Rule Messages OUTBOUND:: "+str(rule_msgs2))

        if 'changes' in rule_msgs2:
            if 'changes' not in rule_msgs:
                rule_msgs['changes'] = []
            rule_msgs['changes'] += rule_msgs2['changes']

        #TODO: Initialize Outbound Policies from RIB
        self.logger.debug("Rule Messages:: "+str(rule_msgs))
        if 'changes' in rule_msgs:
            self.dp_queued.extend(rule_msgs["changes"])


    def push_dp(self):
        '''
        (1) Check if there are any policies queued to be pushed
        (2) Send the queued policies to reference monitor
        '''

        self.logger.debug("Pushing current flow mod queue:")

        # it is crucial that dp_queued is traversed chronologically
        for flowmod in self.dp_queued:
            self.logger.debug("MOD: "+str(flowmod))
            self.fm_builder.add_flow_mod(**flowmod)
            self.dp_pushed.append(flowmod)

        self.dp_queued = []
        self.refmon_client.send(json.dumps(self.fm_builder.get_msg()))


    def stop(self):
        "Stop the Participants' SDN Controller"
        self.logger.info("Stopping Controller. "+str(self.logger_info))

        # Signal Termination and close blocking listener
        self.run = False
        conn = Client(self.cfg.get_eh_info(), authkey=None)
        conn.send("terminate")
        conn.close()

        # TODO: confirm that this isn't silly
        self.xrs_client = None
        self.refmon_client = None
        self.arp_client = None

        # TODO: Think of better way of terminating this listener
        self.listener_eh.close()


    def start_eh(self):
        '''Socket listener for network events '''
        self.logger.info("Event Handler started.")

        while self.run:
            self.logger.debug("EH waiting for connection...")
            conn_eh = self.listener_eh.accept()

            tmp = conn_eh.recv()

            if tmp != "terminate":
                self.logger.debug("EH established connection...")

                data = json.loads(tmp)

                self.logger.debug("Event received of type "+str(data.keys()))

                # Starting a thread for independently processing each incoming network event
                event_processor_thread = Thread(target = self.process_event, args = [data])
                event_processor_thread.daemon = True
                event_processor_thread.start()

                # Send a message back to the sender.
                reply = "Event Received"
                conn_eh.send(reply)
            conn_eh.close()

    def process_event(self, data):
        "Locally process each incoming network event"


        if 'bgp' in data:
            self.logger.debug("Event Received: BGP Update.")
            route = data['bgp']
            # Process the incoming BGP updates from XRS
            #self.logger.debug("BGP Route received: "+str(route)+" "+str(type(route)))
            self.process_bgp_route(route)

        elif 'policy' in data:
            # Process the event requesting change of participants' policies
            self.logger.debug("Event Received: Policy change.")
            change_info = data['policy']
            self.process_policy_changes(change_info)

        elif 'arp' in data:
            (requester_srcmac, requested_vnh) = tuple(data['arp'])
            self.logger.debug("Event Received: ARP request for IP "+str(requested_vnh))
            self.process_arp_request(requester_srcmac, requested_vnh)

        else:
            self.logger.warn("UNKNOWN EVENT TYPE RECEIVED: "+str(data))


    def process_policy_changes(self, change_info):
        "Process the changes in participants' policies"
        # TODO: Implement the logic of dynamically changing participants' outbound and inbound policy
        '''
            change_info =
            {
                'removal_cookies' : [cookie1, ...], # Cookies of deleted policies
                'new_policies' :
                {
                    <policy file format>
                }

            }
        '''
        # remove flow rules for the old policies
        removal_msgs = []

        '''
        for cookie in change_info['removal_cookies']:
            mod =  {"rule_type":"outbound", "priority":0,
                    "match":match_args , "action":{},
                    "cookie":cookie, "mod_type":"remove"}
            removal_msgs.append(mod)
        '''

        self.dp_queued.extend(removal_msgs)


        # add flow rules for the new policies
        if self.cfg.isSupersetsMode():
            dp_msgs = ss_process_policy_change(self.supersets, add_policies, remove_policies, policies,
                                                self.port_count, self.port0_mac)
        else:
            dp_msgs = []

        self.dp_queued.extend(dp_msgs)

        self.push_dp()

        return 0




    def process_arp_request(self, part_mac, vnh):
        vmac = ""
        if self.cfg.isSupersetsMode():
            vmac = self.supersets.get_vmac(self, vnh)
        else:
            vmac = "whoa" # MDS vmac goes here

        arp_responses = list()

        # if this is gratuitous, send a reply to the part's ID
        if part_mac is None:
            gratuitous = True
            # set fields appropriately for gratuitous arps
            i = 0
            for port in self.cfg.ports:
                eth_dst = vmac_part_port_match(self.id, i, self.supersets, False)
                arp_responses.append({'SPA': vnh, 'TPA': vnh,
                                   'SHA': vmac, 'THA': vmac,
                                   'eth_src': vmac, 'eth_dst': eth_dst})
                i += 1

        else: # if it wasn't gratuitous
            gratuitous = False
            # dig up the IP of the target participant
            for port in self.cfg.ports:
                if part_mac == port["MAC"]:
                    part_ip = port["IP"]
                    break

            # set field appropriately for arp responses
            arp_responses.append({'SPA': vnh, 'TPA': part_ip,
                        'SHA': vmac, 'THA': part_mac,
                        'eth_src': vmac, 'eth_dst': part_mac})

        if gratuitous:
            self.logger.debug("Sending Gratuitious ARP: "+str(arp_responses))
        else:
            self.logger.debug("Sending ARP Response: "+str(arp_responses))

        for arp_response in arp_responses:
            self.arp_client.send(json.dumps(arp_response))

    def getlock(self, prefixes):
        prefixes.sort()
        hsh = "-".join(prefixes)
        if hsh not in self.prefix_lock:
            #self.logger.debug("First Lock:: "+str(hsh))
            self.prefix_lock[hsh] = RLock()
        #else:
            #self.logger.debug("Repeat :: "+str(hsh))
        return self.prefix_lock[hsh]

    def process_bgp_route(self, route):
        "Process each incoming BGP advertisement"
        tstart = time.time()

        prefixes = get_prefixes_from_announcements(route)
        with self.getlock(prefixes):
            reply = ''
            # Map to update for each prefix in the route advertisement.
            updates = self.bgp_instance.update(route)
            #self.logger.debug("process_bgp_route:: "+str(updates))
            # TODO: This step should be parallelized
            # TODO: The decision process for these prefixes is going to be same, we
            # should think about getting rid of such redundant computations.
            for update in updates:
                self.bgp_instance.decision_process_local(update)
                self.vnh_assignment(update)

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken for decision process: "+str(elapsed))
                tstart = time.time()

            if self.cfg.isSupersetsMode():
            ################## SUPERSET RESPONSE TO BGP ##################
                # update supersets
                "Map the set of BGP updates to a list of superset expansions."
                ss_changes, ss_changed_prefs = self.supersets.update_supersets(self, updates)

                if TIMING:
                    elapsed = time.time() - tstart
                    self.logger.debug("Time taken to update supersets: "+str(elapsed))
                    tstart = time.time()

                # ss_changed_prefs are prefixes for which the VMAC bits have changed
                # these prefixes must have gratuitous arps sent
                garp_required_vnhs = [self.prefix_2_VNH[prefix] for prefix in ss_changed_prefs]

                "If a recomputation event was needed, wipe out the flow rules."
                if ss_changes["type"] == "new":
                    self.logger.debug("Wiping outbound rules.")
                    wipe_msgs = msg_clear_all_outbound(self.policies, self.port0_mac)
                    self.dp_queued.extend(wipe_msgs)

                    #if a recomputation was needed, all VMACs must be reARPed
                    # TODO: confirm reARPed is a word
                    garp_required_vnhs = self.VNH_2_prefix.keys()

                if len(ss_changes['changes']) > 0:

                    self.logger.debug("Supersets have changed: "+str(ss_changes))

                    "Map the superset changes to a list of new flow rules."
                    flow_msgs = update_outbound_rules(ss_changes, self.policies,
                            self.supersets, self.port0_mac)

                    self.logger.debug("Flow msgs: "+str(flow_msgs))
                    "Dump the new rules into the dataplane queue."
                    self.dp_queued.extend(flow_msgs)

                if TIMING:
                    elapsed = time.time() - tstart
                    self.logger.debug("Time taken to deal with ss_changes: "+str(elapsed))
                    tstart = time.time()

            ################## END SUPERSET RESPONSE ##################

            else:
                # TODO: similar logic for MDS
                self.logger.debug("Creating ctrlr messages for MDS scheme")

            self.push_dp()

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken to push dp msgs: "+str(elapsed))
                tstart = time.time()

            changed_vnhs, announcements = self.bgp_instance.bgp_update_peers(updates,
                    self.prefix_2_VNH, self.cfg.ports)

            """ Combine the VNHs which have changed BGP default routes with the
                VNHs which have changed supersets.
            """

            changed_vnhs = set(changed_vnhs)
            changed_vnhs.update(garp_required_vnhs)

            # Send gratuitous ARP responses for all them
            for vnh in changed_vnhs:
                self.process_arp_request(None, vnh)

            # Tell Route Server that it needs to announce these routes
            for announcement in announcements:
                # TODO: Complete the logic for this function
                self.send_announcement(announcement)

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken to send garps/announcements: "+str(elapsed))
                tstart = time.time()

            return reply


    def send_announcement(self, announcement):
        "Send the announcements to XRS"
        self.logger.debug("Sending announcements to XRS. "+str(type(announcement)))

        self.xrs_client.send(json.dumps(announcement))


    def vnh_assignment(self, update):
        "Assign VNHs for the advertised prefixes"
        if self.cfg.isSupersetsMode():
            " Superset"
            # TODO: Do we really need to assign a VNH for each advertised prefix?
            if ('announce' in update):
                prefix = update['announce'].prefix

                if (prefix not in self.prefix_2_VNH):
                    # get next VNH and assign it the prefix
                    self.num_VNHs_in_use += 1
                    vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])

                    self.prefix_2_VNH[prefix] = vnh
                    self.VNH_2_prefix[vnh] = prefix
        else:
            "Disjoint"
            # TODO: @Robert: Place your logic here for VNH assignment for MDS scheme
            self.logger.debug("VNH assignment called for disjoint vmac_mode")


    def init_vnh_assignment(self):
        "Assign VNHs for the advertised prefixes"
        if self.cfg.isSupersetsMode():
            " Superset"
            # TODO: Do we really need to assign a VNH for each advertised prefix?
            #self.bgp_instance.rib["local"].dump()
            prefixes = self.bgp_instance.rib["local"].get_prefixes()
            #print 'init_vnh_assignment: prefixes:', prefixes
            #print 'init_vnh_assignment: prefix_2_VNH:', self.prefix_2_VNH
            for prefix in prefixes:
                if (prefix not in self.prefix_2_VNH):
                    # get next VNH and assign it the prefix
                    self.num_VNHs_in_use += 1
                    vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])

                    self.prefix_2_VNH[prefix] = vnh
                    self.VNH_2_prefix[vnh] = prefix
        else:
            "Disjoint"
            # TODO: @Robert: Place your logic here for VNH assignment for MDS scheme
            self.logger.debug("VNH assignment called for disjoint vmac_mode")
Пример #6
0
class ParticipantController(object):
    def __init__(self, id, config_file, policy_file, logger):
        # participant id
        self.id = id
        self.logger = logger

        # used to signal termination
        self.run = True
        self.prefix_lock = {}

        # Initialize participant params
        self.cfg = PConfig(config_file, self.id)

        # load policies
        self.policies = self.load_policies(policy_file)

        # The port 0 MAC is used for tagging outbound rules as belonging to us
        self.port0_mac = self.cfg.port0_mac

        self.nexthop_2_part = self.cfg.get_nexthop_2_part()

        # VNHs related params
        self.num_VNHs_in_use = 0
        self.VNH_2_vmac = {}
        self.vmac_2_VNH = {}
        self.FEC_list = {}
        self.prefix_2_FEC = {}
        self.prefix_2_VNH_nrfp = {}
        #SWIFT Backup equivalence class
        self.BEC_list = {((-1, -1, -1), (-1, -1, -1)): {'id': 1, 'as_path': None, 'backup_nbs': None, 'as_path_vmac': None}}
        self.prefix_2_BEC = {}
        self.BECid_FECid_2_VNH = {}
        self.prefix_2_BEC_nrfp = {}
        self.max_depth = self.cfg.Swift_vmac["max_depth"]
        self.nexthops_nb_bits = self.cfg.Swift_vmac["nexthops_nb_bits"]
        self.Swift_flow_rule_timeout = self.cfg.Swift_vmac["hard timeout"]
        self.vnh_2_BFEC = {}
        #swift tag dic mapping ip to mac
        self.tag_dict = {}
        self.prefix_2_FEC_nrfp = {}
        self.prefix_2_BEC_nrfp = {}

        # Superset related params
        if self.cfg.isSupersetsMode():
            self.supersets = SuperSets(self, self.cfg.vmac_options)

        # Keep track of flow rules pushed
        self.dp_pushed = []
        # Keep track of flow rules which are scheduled to be pushed
        self.dp_queued = []

    def xstart(self):
        # Start all clients/listeners/whatevs
        self.logger.info("Starting controller for participant")

        # ExaBGP Peering Instance
        self.bgp_instance = self.cfg.get_bgp_instance()
        self.FEC = FEC(self)
        self.BEC = BEC(self)

        # Route server client, Reference monitor client, Arp Proxy client
        self.xrs_client = self.cfg.get_xrs_client(self.logger)
        self.xrs_client.send({'msgType': 'hello', 'id': self.cfg.id, 'peers_in': self.cfg.peers_in, 'peers_out': self.cfg.peers_out, 'ports': self.cfg.get_ports()})

        self.arp_client = self.cfg.get_arp_client(self.logger)
        self.arp_client.send({'msgType': 'hello', 'macs': self.cfg.get_macs()})

        # Participant Server for dynamic route updates
        self.participant_server = self.cfg.get_participant_server(self.id, self.logger)
        if self.participant_server is not None:
            self.participant_server.start(self)

        self.refmon_client = self.cfg.get_refmon_client(self.logger)

        # Send flow rules for initial policies to the SDX's Reference Monitor
        self.initialize_dataplane()
        self.push_dp()

        # Start the event handlers
        ps_thread_arp = Thread(target=self.start_eh_arp)
        ps_thread_arp.daemon = True
        ps_thread_arp.start()

        ps_thread_xrs = Thread(target=self.start_eh_xrs)
        ps_thread_xrs.daemon = True
        ps_thread_xrs.start()

        ps_thread_arp.join()
        ps_thread_xrs.join()
        self.logger.debug("Return from ps_thread.join()")

    def sanitize_policies(self, policies):

        port_count = len(self.cfg.ports)

        # sanitize the inbound policies
        if 'inbound' in policies:
            for policy in policies['inbound']:
                if 'action' not in policy:
                    continue
                if 'fwd' in policy['action'] and int(policy['action']['fwd']) >= port_count:
                    policy['action']['fwd'] = 0
                    self.logger.warn('Port count in inbound policy is too big.  Setting it to 0.')

        # sanitize the outbound policies
        if 'outbound' in policies:
            for policy in policies['outbound']:
                # If no cookie field, give it cookie 0. (Should be OK for multiple flows with same cookie,
                # though they can't be individually removed.)
                if 'cookie' not in policy:
                    policy['cookie'] = 0
                    self.logger.warn('Cookie not specified in new policy.  Defaulting to 0.')

        return policies

    def load_policies(self, policy_file):
        # Load policies from file

        with open(policy_file, 'r') as f:
            policies = json.load(f)

        return self.sanitize_policies(policies)

    def initialize_dataplane(self):
        "Read the config file and update the queued policy variable"

        self.logger.info("Initializing inbound rules")

        final_switch = "main-in"
        if self.cfg.isMultiTableMode():
            final_switch = "main-out"

        self.FEC.init_FEC_assignment()
        self.BEC.init_BEC_assignment()
        self.init_vnh_assignment()

        rule_msgs = init_inbound_rules(self.id, self.policies,
                                        self.supersets, final_switch)
        self.logger.debug("Rule Messages INBOUND:: "+json.dumps(rule_msgs))

        rule_msgs2 = init_outbound_rules(self, self.id, self.policies,
                                        self.supersets, final_switch)
        self.logger.debug("Rule Messages OUTBOUND:: "+json.dumps(rule_msgs2))

        if 'changes' in rule_msgs2:
            if 'changes' not in rule_msgs:
                rule_msgs['changes'] = []
            rule_msgs['changes'] += rule_msgs2['changes']

        #TODO: Initialize Outbound Policies from RIB
        self.logger.debug("Rule Messages:: "+json.dumps(rule_msgs))
        if 'changes' in rule_msgs:
            self.dp_queued.extend(rule_msgs["changes"])

    def push_dp(self):
        '''
        (1) Check if there are any policies queued to be pushed
        (2) Send the queued policies to reference monitor
        '''

        self.logger.debug("Pushing current flow mod queue:")

        # it is crucial that dp_queued is traversed chronologically
        fm_builder = FlowModMsgBuilder(self.id, self.refmon_client.key)
        for flowmod in self.dp_queued:
            self.logger.debug("MOD: "+str(flowmod))
            if (flowmod['mod_type'] == 'remove'):
                fm_builder.delete_flow_mod(flowmod['mod_type'], flowmod['rule_type'], flowmod['cookie'][0], flowmod['cookie'][1])
            elif (flowmod['mod_type'] == 'insert'):
                fm_builder.add_flow_mod(**flowmod)
            else:
                self.logger.error("Unhandled flow type: " + flowmod['mod_type'])
                continue
            self.dp_pushed.append(flowmod)

        self.dp_queued = []
        self.refmon_client.send(json.dumps(fm_builder.get_msg()))

    def stop(self):
        "Stop the Participants' SDN Controller"

        self.logger.info("Stopping Controller.")

        # Signal Termination and close blocking listener
        self.run = False

    def start_eh_arp(self):
        self.logger.info("ARP Event Handler started.")

        while self.run:
            # need to poll since recv() will not detect close from this end
            # and need some way to shutdown gracefully.
            if not self.arp_client.poll(1):
                continue
            try:
                tmp = self.arp_client.recv()
            except EOFError:
                break

            data = json.loads(tmp)
            self.logger.debug("ARP Event received: %s", data)

            # Starting a thread for independently processing each incoming network event
            event_processor_thread = Thread(target=self.process_event, args=(data,))
            event_processor_thread.daemon = True
            event_processor_thread.start()

        self.arp_client.close()
        self.logger.debug("Exiting start_eh_arp")

    def start_eh_xrs(self):
        self.logger.info("XRS Event Handler started.")

        while self.run:
            # need to poll since recv() will not detect close from this end
            # and need some way to shutdown gracefully.
            if not self.xrs_client.poll(1):
                continue
            try:
                tmp = self.xrs_client.recv()
            except EOFError:
                break

            data = tmp
            self.logger.debug("XRS Event received: %s", data)

            self.process_event(data)

        self.xrs_client.close()
        self.logger.debug("Exiting start_eh_xrs")

    def process_event(self, data):
        "Locally process each incoming network event"

        #@TODO: when receiving swift FR push backup rules
        if 'FR' in data:
            self.logger.info("Event Received: FR request"+ str(data))
            self.logger.debug("Event Received: FR request")
            FR_parameters = data['FR']
            self.process_FR(FR_parameters)

        elif 'down' in data:
            self.logger.info("processing down participant")
            down_ip = data['down']
            self.deal_with_local_failure(down_ip)

        elif 'bgp' in data :
            self.logger.debug("Event Received: BGP Update.")
            update = data['bgp']
            # Process the incoming BGP updates from XRS
            #self.logger.debug("BGP Route received: "+str(route)+" "+str(type(route)))
            self.process_bgp_route(update)

        elif 'policy' in data:
            # Process the event requesting change of participants' policies
            self.logger.debug("Event Received: Policy change.")
            change_info = data['policy']
            self.process_policy_changes(change_info)

        elif 'arp' in data:
            (requester_srcmac, requested_vnh) = tuple(data['arp'])
            self.logger.debug("Event Received: ARP request for IP "+str(requested_vnh))
            self.process_arp_request(requester_srcmac, requested_vnh)

        else:
            self.logger.warn("UNKNOWN EVENT TYPE RECEIVED: "+str(data))

    #@TODO: Make sure the message type sent from route-server matches
    def process_FR(self, FR_parameters):
        peer_id = FR_parameters['peer_id']
        as_path_vmac = FR_parameters['as_path_vmac']
        as_path_bitmask = FR_parameters['as_path_bitmask']
        depth = FR_parameters['depth']
        rules = []
        if depth > self.max_depth+1:
            return
        for backup_part in self.tag_dict.keys():
            if backup_part != peer_id:
                backup_vmac = ''
                backup_bitmask = ''
                for i in range(1, self.max_depth+1):
                    if i == depth:
                        backup_tag = self.tag_dict[backup_part]
                        backup_vmac += bin(backup_tag)[2:].zfill(self.nexthops_nb_bits)
                        backup_bitmask += '1' * self.nexthops_nb_bits

                    else:
                        backup_vmac += '0' * self.nexthops_nb_bits
                        backup_bitmask += '0' * self.nexthops_nb_bits


                next_hop_match = vmac_next_hop_match_iSDXmac_bitsring(peer_id, self.supersets,only_isdx_vmac=True)
                next_hop_mask = vmac_next_hop_mask_iSDXmac_bitstring(self.supersets, only_isdx_vmac=True)

                vmac = next_hop_match + backup_vmac + as_path_vmac
                vmac_bitmask = next_hop_mask + backup_bitmask + as_path_bitmask
                vmac = '{num:0{width}x}'.format(num=int(vmac, 2), width=48 / 4)
                vmac= ':'.join([vmac[i] + vmac[i + 1] for i in range(0, 48 / 4, 2)])
                vmac_bitmask = '{num:0{width}x}'.format(num=int(vmac_bitmask, 2), width=48 / 4)
                vmac_bitmask = ':'.join([vmac_bitmask[i] + vmac_bitmask[i + 1] for i in range(0, 48 / 4, 2)])

                for port in self.cfg.get_macs():


                    match_args = {
                        "eth_dst": (vmac, vmac_bitmask),
                    }

                    match_args["eth_src"] = port

                    #set dst mac to mac with best next hop
                    dst_mac = vmac_next_hop_match_iSDXmac(backup_part, self.supersets, inbound_bit=True)
                    actions = {"set_eth_dst": dst_mac, "fwd": ["outbound"]}
                    rule = {
                        "mod_type": "insert",
                        "rule_type": "main-in",
                        "priority": "fast_reroute",
                        "match": match_args,
                        "action": actions,
                        "hard_timeout": self.Swift_flow_rule_timeout
                    }
                    rules.append(rule)

                    self.logger.info("FR - rule:" + str(vmac)+ str(dst_mac))

                    print self.id, "FR rule match:", (vmac, vmac_bitmask)
                    print self.id, "VNH2VMAC", self.VNH_2_vmac
                    print self.id, "tag_dict:", self.tag_dict

        self.dp_queued.extend(rules)

        self.push_dp()

        self.logger.info("finished pushing FR rules")


    def update_policies(self, new_policies, in_out):
        if in_out != 'inbound' and in_out != 'outbound':
            self.logger.exception("Illegal argument to update_policies: " + in_out)
            raise
        if in_out not in new_policies:
            return
        if in_out not in self.policies:
            self.policies[in_out] = []
        new_cookies = {x['cookie'] for x in new_policies[in_out] if 'cookie' in x}
        self.logger.debug('new_cookies: ' + str(new_cookies))

        # remove any items with same cookie (TODO: verify that this is the behavior we want)
        self.policies[in_out] = [x for x in self.policies[in_out] if x['cookie'] not in new_cookies]
        self.logger.debug('new_policies[io]: ' + str(new_policies[in_out]))
        self.policies[in_out].extend(new_policies[in_out])

    # Remove polices that match the cookies and return the list of cookies for removed policies
    def remove_policies_by_cookies(self, cookies, in_out):
        if in_out != 'inbound' and in_out != 'outbound':
            self.logger.exception("Illegal argument to update_policies: " + in_out)
            raise
        if in_out in self.policies:
            to_remove = [x['cookie'] for x in self.policies[in_out] if x['cookie'] in cookies]
            self.policies[in_out] = [x for x in self.policies[in_out] if x['cookie'] not in cookies]
            self.logger.debug('removed cookies: ' + str(to_remove) + ' from: ' + in_out)
            return to_remove
        return []

    def queue_flow_removals(self, cookies, in_out):
        removal_msgs = []
        for cookie in cookies:
            mod =  {"rule_type":in_out,
                    "cookie":(cookie,2**16-1), "mod_type":"remove"}
            removal_msgs.append(mod)
        self.logger.debug('queue_flow_removals: ' + str(removal_msgs))
        self.dp_queued.extend(removal_msgs)

    def process_policy_changes(self, change_info):
        if not self.cfg.isSupersetsMode():
            self.logger.warn('Dynamic policy updates only supported in SuperSet mode')
            return

        # First step towards a less brute force approach: Handle removals without having to remove everything
        if 'removal_cookies' in change_info:
            cookies = change_info['removal_cookies']
            removed_in_cookies = self.remove_policies_by_cookies(cookies, 'inbound')
            self.queue_flow_removals(removed_in_cookies, 'inbound')
            removed_out_cookies = self.remove_policies_by_cookies(cookies, 'outbound')
            self.queue_flow_removals(removed_out_cookies, 'outbound')
            if not 'new_policies' in change_info:
                self.push_dp()
                return

        # Remainder of this method is brute force approach: wipe everything and re-do it
        # This should be replaced by a more fine grained approach
        self.logger.debug("Wiping outbound rules.")
        wipe_msgs = msg_clear_all_outbound(self.policies, self.port0_mac)
        self.dp_queued.extend(wipe_msgs)

        self.logger.debug("pre-updated policies: " + json.dumps(self.policies))
        if 'removal_cookies' in change_info:
            cookies = change_info['removal_cookies']
            self.remove_policies_by_cookies(cookies, 'inbound')
            self.remove_policies_by_cookies(cookies, 'outbound')

        if 'new_policies' in change_info:
            new_policies = change_info['new_policies']
            self.sanitize_policies(new_policies)
            self.update_policies(new_policies, 'inbound')
            self.update_policies(new_policies, 'outbound')

        self.logger.debug("updated policies: " + json.dumps(self.policies))
        self.logger.debug("pre-recomputed supersets: " + json.dumps(self.supersets.supersets))

        self.initialize_dataplane()
        self.push_dp()

        # Send gratuitous ARP responses for all
        garp_required_FECs = self.prefix_2_FEC.values()['vnh']
        #garp_required_vnhs = self.VNH_2_prefix.keys()
        for FEC in garp_required_FECs:
            self.process_arp_request(None, FEC)
            
        return

    def process_arp_request(self, part_mac, vnh):
        vmac = ""
        #if self.cfg.isSupersetsMode():
            #vmac = self.supersets.get_vmac(self, FEC)

        arp_responses = list()

        # if this is gratuitous, send a reply to the part's ID
        if part_mac is None:
            gratuitous = True
            # set fields appropriately for gratuitous arps
            vmac = self.supersets.get_vmac(self, vnh)
            i = 0
            self.VNH_2_vmac[vnh] = vmac
            self.vmac_2_VNH[vmac] = vnh
            for port in self.cfg.ports:
                eth_dst = vmac_part_port_match(self.id, i, self.supersets, False)
                arp_responses.append({'SPA': vnh, 'TPA': vnh,
                                   'SHA': vmac, 'THA': vmac,
                                   'eth_src': vmac, 'eth_dst': eth_dst})
                i += 1

        else: # if it wasn't gratuitous
            gratuitous = False
            # dig up the IP of the target participant
            if vnh not in self.VNH_2_vmac:
                return
            vmac = self.VNH_2_vmac[vnh]
            for port in self.cfg.ports:
                if part_mac == port["MAC"]:
                    part_ip = port["IP"]
                    break

            # set field appropriately for arp responses
            arp_responses.append({'SPA': vnh, 'TPA': part_ip,
                        'SHA': vmac, 'THA': part_mac,
                        'eth_src': vmac, 'eth_dst': part_mac})

        if gratuitous:
            self.logger.debug("Sending Gratuitious ARP: ")
        else:
            self.logger.debug("Sending ARP Response: ")

        for arp_response in arp_responses:
            arp_response['msgType'] = 'garp'
            self.arp_client.send(arp_response)


    def getlock(self, prefixes):
        prefixes.sort()
        hsh = "-".join(prefixes)
        if hsh not in self.prefix_lock:
            #self.logger.debug("First Lock:: "+str(hsh))
            self.prefix_lock[hsh] = RLock()
        #else:
            #self.logger.debug("Repeat :: "+str(hsh))
        return self.prefix_lock[hsh]

    def process_bgp_route(self, update):

        "Process each incoming BGP advertisement"
        tstart = time.time()

        #Check for local failure, push fast reroute rules if local failure
        #self.deal_with_local_failure(routes)

        # Map to update for each prefix in the route advertisement.
        self.bgp_instance.update(update)
        self.logger.info("process_bgp_route:: " + str(update))
        self.logger.debug("process_bgp_route:: "+str(update))
        # TODO: This step should be parallelized
        # TODO: The decision process for these prefixes is going to be same, we
        # should think about getting rid of such redundant computations.
        self.bgp_instance.decision_process(update)
        #assign FEC to prefix
        self.FEC.assignment(update)
        #assign BEC to prefix
        self.BEC.assignment(update)
        #assign VNH to FEC, BEC pair of prefix
        self.vnh_assignment(update)

        if TIMING:
            elapsed = time.time() - tstart
            #self.logger.info("Time taken for decision process: " + str(elapsed))
            self.logger.debug("Time taken for decision process: " + str(elapsed))
            tstart = time.time()


        if self.cfg.isSupersetsMode():
            ################## SUPERSET RESPONSE TO BGP ##################
            # update supersets
            "Map the set of BGP updates to a list of superset expansions."
            ss_changes, ss_changed_prefs = self.supersets.update_supersets(self, update)

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken to update supersets: "+str(elapsed))
                tstart = time.time()

            # ss_changed_prefs are prefixes for which the VMAC bits have changed
            # these prefixes must have gratuitous arps sent
            garp_required_VNHs = []
            for prefix in ss_changed_prefs:
                BEC_id = self.prefix_2_BEC[prefix]['id']
                FEC_id = self.prefix_2_FEC[prefix]['id']
                garp_required_VNHs.append(self.BECid_FECid_2_VNH[(BEC_id,FEC_id)])

            "If a recomputation event was needed, wipe out the flow rules."
            if ss_changes["type"] == "new":
                self.logger.debug("Wiping outbound rules.")
                wipe_msgs = msg_clear_all_outbound(self.policies, self.port0_mac)
                self.dp_queued.extend(wipe_msgs)

                #if a recomputation was needed, all VMACs must be reARPed
                # TODO: confirm reARPed is a word
                #garp_required_vnhs = self.VNH_2_prefix.keys()
                garp_required_VNHs =[]
                for VNH in self.BECid_FECid_2_VNH.values():
                    garp_required_VNHs.append(VNH)
                #garp_required_vnhs = self.prefix_2_FEC.values()['vnh']

            if len(ss_changes['changes']) > 0:

                self.logger.debug("Supersets have changed: "+str(ss_changes))

                "Map the superset changes to a list of new flow rules."
                flow_msgs = update_outbound_rules(ss_changes, self.policies,
                        self.supersets, self.port0_mac)

                self.logger.debug("Flow msgs: "+str(flow_msgs))
                "Dump the new rules into the dataplane queue."
                self.dp_queued.extend(flow_msgs)

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken to deal with ss_changes: "+str(elapsed))
                tstart = time.time()

        ################## END SUPERSET RESPONSE ##################

        else:
            # TODO: similar logic for MDS
            self.logger.debug("Creating ctrlr messages for MDS scheme")

        if len(self.dp_queued) != 0:
            self.push_dp()

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.debug("Time taken to push dp msgs: "+str(elapsed))
            tstart = time.time()

        new_VNHs, announcements = self.bgp_instance.bgp_update_peer(update,self.prefix_2_VNH_nrfp,
                self.prefix_2_FEC, self.prefix_2_BEC, self.BECid_FECid_2_VNH, self.VNH_2_vmac, self.cfg.ports)

        """ Combine the VNHs which have changed BGP default routes with the
            VNHs which have changed supersets.
        """

        #new_FECs = set(new_FECs)

        new_VNHs = new_VNHs + garp_required_VNHs

        #remove duplicates
        new_VNHs = list(set(new_VNHs))

        # Send gratuitous ARP responses for all them
        for VNH in new_VNHs:
            self.process_arp_request(None, VNH)

        # Tell Route Server that it needs to announce these routes
        for announcement in announcements:
            # TODO: Complete the logic for this function
            self.send_announcement(announcement)

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.info("Time taken to send garps/announcements: "+str(elapsed))
            self.logger.debug("Time taken to send garps/announcements: " + str(elapsed))
            tstart = time.time()

        #print self.id, "BEC_list", self.BEC_list
        #print self.id, "VHN_2_VMAC", self.VNH_2_vmac

    def send_announcement(self, announcement):
        "Send the announcements to XRS"
        #self.logger.debug("Sending announcements to XRS: %s", announcement)
        self.xrs_client.send({'msgType': 'bgp', 'announcement': announcement})

    def vnh_assignment(self,update):
        if self.cfg.isSupersetsMode():
            if 'announce' in update:
                prefix = update['announce'].prefix
            if 'withdraw' in update:
                prefix = update['withdraw'].prefix
            if prefix:
                route = self.bgp_instance.get_routes('local', False, prefix = prefix)
                if route:
                    FEC_id = self.prefix_2_FEC[prefix]['id']
                    BEC_id = self.prefix_2_BEC[prefix]['id']
                    if (BEC_id, FEC_id) not in self.BECid_FECid_2_VNH:
                        self.num_VNHs_in_use += 1
                        vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])
                        if vnh in self.nexthop_2_part:
                            self.num_VNHs_in_use += 1
                            vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])
                        self.BECid_FECid_2_VNH[(BEC_id, FEC_id)] = vnh
                        self.vnh_2_BFEC[vnh] = [self.prefix_2_BEC[prefix], self.prefix_2_FEC[prefix]]
                    else:
                        vnh = self.BECid_FECid_2_VNH[(BEC_id, FEC_id)]
                        self.vnh_2_BFEC[vnh] = [self.prefix_2_BEC[prefix], self.prefix_2_FEC[prefix]]
                else:
                    BEC_id = self.prefix_2_BEC_nrfp[prefix]['id']
                    FEC_id = self.prefix_2_FEC_nrfp[prefix]['id']
                    self.prefix_2_VNH_nrfp[prefix] = self.BECid_FECid_2_VNH[(BEC_id,FEC_id)]





    def init_vnh_assignment(self):
        if self.cfg.isSupersetsMode():
            bgp_routes = self.bgp_instance.get_routes('local', True)
            for bgp_route in bgp_routes:
                prefix = bgp_route.prefix
                FEC_id = self.prefix_2_FEC[prefix]['id']
                BEC_id = self.prefix_2_BEC[prefix]['id']
                if (BEC_id, FEC_id) not in self.BECid_FECid_2_VNH:
                    self.num_VNHs_in_use += 1
                    vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])
                    if vnh in self.nexthop_2_part:
                        self.num_VNHs_in_use += 1
                        vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])
                    self.BECid_FECid_2_VNH[(BEC_id, FEC_id)] = vnh
                    self.vnh_2_BFEC[vnh] = [self.prefix_2_BEC[prefix], self.prefix_2_FEC[prefix]]

    def deal_with_local_failure(self,down_ip):
        route_list = []

        #@TODO: PUSH BACKUP RULES IF NECESSARY

        routes = self.bgp_instance.get_routes('input', True, neighbor=down_ip)
        for route_item in routes:
            route_list.append({'withdraw': route_item})

        self.bgp_instance.delete_all_routes('input', neighbor=down_ip)

        for route in route_list:
            self.process_bgp_route(route)
Пример #7
0
class ParticipantController(object):
    def __init__(self, id, config_file, policy_file, logger):
        # participant id
        self.id = id
        # print ID for logging
        self.logger = logger

        # used to signal termination
        self.run = True
        self.prefix_lock = {}

        # Initialize participant params
        self.cfg = PConfig(config_file, self.id)
        # Vmac encoding mode
        # self.cfg.vmac_mode = config_file["vmac_mode"]
        # Dataplane mode---multi table or multi switch
        # self.cfg.dp_mode = config_file["dp_mode"]


        self.policies = self.load_policies(policy_file)

        # The port 0 MAC is used for tagging outbound rules as belonging to us
        self.port0_mac = self.cfg.port0_mac

        self.nexthop_2_part = self.cfg.get_nexthop_2_part()

        # VNHs related params
        self.num_VNHs_in_use = 0
        self.VNH_2_prefix = {}
        self.prefix_2_VNH = {}


        # Superset related params
        if self.cfg.isSupersetsMode():
            self.supersets = SuperSets(self, self.cfg.vmac_options)
        else:
            # TODO: create similar class and variables for MDS
            self.mds = None

        # Keep track of flow rules pushed
        self.dp_pushed = []
        # Keep track of flow rules which are scheduled to be pushed
        self.dp_queued = []


    def xstart(self):
        # Start all clients/listeners/whatevs
        self.logger.info("Starting controller for participant")

        # ExaBGP Peering Instance
        self.bgp_instance = self.cfg.get_bgp_instance()

        # Route server client, Reference monitor client, Arp Proxy client
        self.xrs_client = self.cfg.get_xrs_client(self.logger)
	self.xrs_client.send({'msgType': 'hello', 'id': self.cfg.id, 'peers_in': self.cfg.peers_in, 'peers_out': self.cfg.peers_out, 'ports': self.cfg.get_ports()})

        self.arp_client = self.cfg.get_arp_client(self.logger)
        self.arp_client.send({'msgType': 'hello', 'macs': self.cfg.get_macs()})

        # Participant Server for dynamic route updates
        self.participant_server = self.cfg.get_participant_server(self.id, self.logger)
        if self.participant_server is not None:
            self.participant_server.start(self)

        self.refmon_client = self.cfg.get_refmon_client(self.logger)

        # Send flow rules for initial policies to the SDX's Reference Monitor
        self.initialize_dataplane()
        self.push_dp()

        # Start the event handlers
        ps_thread_arp = Thread(target=self.start_eh_arp)
        ps_thread_arp.daemon = True
        ps_thread_arp.start()

        ps_thread_xrs = Thread(target=self.start_eh_xrs)
        ps_thread_xrs.daemon = True
        ps_thread_xrs.start()

        ps_thread_arp.join()
        ps_thread_xrs.join()
        self.logger.debug("Return from ps_thread.join()")

    def sanitize_policies(self, policies):

        port_count = len(self.cfg.ports)

        # sanitize the inbound policies
        if 'inbound' in policies:
            for policy in policies['inbound']:
                if 'action' not in policy:
                    continue
                if 'fwd' in policy['action'] and int(policy['action']['fwd']) >= port_count:
                    policy['action']['fwd'] = 0
                    self.logger.warn('Port count in inbound policy is too big.  Setting it to 0.')

        # sanitize the outbound policies
        if 'outbound' in policies:
            for policy in policies['outbound']:
                # If no cookie field, give it cookie 0. (Should be OK for multiple flows with same cookie,
                # though they can't be individually removed.  TODO: THIS SHOULD BE VERIFIED)
                if 'cookie' not in policy:
                    policy['cookie'] = 0
                    self.logger.warn('Cookie not specified in new policy.  Defaulting to 0.')

        return policies


    def load_policies(self, policy_file):
        # Load policies from file

        with open(policy_file, 'r') as f:
            policies = json.load(f)

        return self.sanitize_policies(policies)


    def initialize_dataplane(self):
        "Read the config file and update the queued policy variable"

        self.logger.info("Initializing inbound rules")

        final_switch = "main-in"
        if self.cfg.isMultiTableMode():
            final_switch = "main-out"

        self.init_vnh_assignment()

        rule_msgs = init_inbound_rules(self.id, self.policies,
                                        self.supersets, final_switch)
        self.logger.debug("Rule Messages INBOUND:: "+json.dumps(rule_msgs))

        rule_msgs2 = init_outbound_rules(self, self.id, self.policies,
                                        self.supersets, final_switch)
        self.logger.debug("Rule Messages OUTBOUND:: "+json.dumps(rule_msgs2))

        if 'changes' in rule_msgs2:
            if 'changes' not in rule_msgs:
                rule_msgs['changes'] = []
            rule_msgs['changes'] += rule_msgs2['changes']

        #TODO: Initialize Outbound Policies from RIB
        self.logger.debug("Rule Messages:: "+json.dumps(rule_msgs))
        if 'changes' in rule_msgs:
            self.dp_queued.extend(rule_msgs["changes"])


    def push_dp(self):
        '''
        (1) Check if there are any policies queued to be pushed
        (2) Send the queued policies to reference monitor
        '''

        self.logger.debug("Pushing current flow mod queue:")

        # it is crucial that dp_queued is traversed chronologically
        fm_builder = FlowModMsgBuilder(self.id, self.refmon_client.key)
        for flowmod in self.dp_queued:
            self.logger.debug("MOD: "+str(flowmod))
            if (flowmod['mod_type'] == 'remove'):
                fm_builder.delete_flow_mod(flowmod['mod_type'], flowmod['rule_type'], flowmod['cookie'][0], flowmod['cookie'][1])
            elif (flowmod['mod_type'] == 'insert'):
                fm_builder.add_flow_mod(**flowmod)
            else:
                self.logger.error("Unhandled flow type: " + flowmod['mod_type'])
                continue
            self.dp_pushed.append(flowmod)

        self.dp_queued = []
        self.refmon_client.send(json.dumps(fm_builder.get_msg()))


    def stop(self):
        "Stop the Participants' SDN Controller"

        self.logger.info("Stopping Controller.")

        # Signal Termination and close blocking listener
        self.run = False

        # TODO: confirm that this isn't silly
        #self.refmon_client = None


    def start_eh_arp(self):
        self.logger.info("ARP Event Handler started.")

        while self.run:
            # need to poll since recv() will not detect close from this end
            # and need some way to shutdown gracefully.
            if not self.arp_client.poll(1):
                continue
            try:
                tmp = self.arp_client.recv()
            except EOFError:
                break

            data = json.loads(tmp)
            self.logger.debug("ARP Event received: %s", data)

            # Starting a thread for independently processing each incoming network event
            event_processor_thread = Thread(target=self.process_event, args=(data,))
            event_processor_thread.daemon = True
            event_processor_thread.start()

        self.arp_client.close()
        self.logger.debug("Exiting start_eh_arp")


    def start_eh_xrs(self):
        self.logger.info("XRS Event Handler started.")

        while self.run:
            # need to poll since recv() will not detect close from this end
            # and need some way to shutdown gracefully.
            if not self.xrs_client.poll(1):
                continue
            try:
                tmp = self.xrs_client.recv()
            except EOFError:
                break

            data = json.loads(tmp)
            self.logger.debug("XRS Event received: %s", json.dumps(data))

            self.process_event(data)

        self.xrs_client.close()
        self.logger.debug("Exiting start_eh_xrs")


    def process_event(self, data):
        "Locally process each incoming network event"


        if 'bgp' in data:
            self.logger.debug("Event Received: BGP Update.")
            route = data['bgp']
            # Process the incoming BGP updates from XRS
            #self.logger.debug("BGP Route received: "+str(route)+" "+str(type(route)))
            self.process_bgp_route(route)

        elif 'policy' in data:
            # Process the event requesting change of participants' policies
            self.logger.debug("Event Received: Policy change.")
            change_info = data['policy']
            self.process_policy_changes(change_info)

        elif 'arp' in data:
            (requester_srcmac, requested_vnh) = tuple(data['arp'])
            self.logger.debug("Event Received: ARP request for IP "+str(requested_vnh))
            self.process_arp_request(requester_srcmac, requested_vnh)

        else:
            self.logger.warn("UNKNOWN EVENT TYPE RECEIVED: "+str(data))


    def update_policies(self, new_policies, in_out):
        if in_out != 'inbound' and in_out != 'outbound':
            self.logger.exception("Illegal argument to update_policies: " + in_out)
            raise
        if in_out not in new_policies:
            return
        if in_out not in self.policies:
            self.policies[in_out] = []
        new_cookies = {x['cookie'] for x in new_policies[in_out] if 'cookie' in x}
        self.logger.debug('new_cookies: ' + str(new_cookies))

        # remove any items with same cookie (TODO: verify that this is the behavior we want)
        self.policies[in_out] = [x for x in self.policies[in_out] if x['cookie'] not in new_cookies]
        self.logger.debug('new_policies[io]: ' + str(new_policies[in_out]))
        self.policies[in_out].extend(new_policies[in_out])

    # Remove polices that match the cookies and return the list of cookies for removed policies
    def remove_policies_by_cookies(self, cookies, in_out):
        if in_out != 'inbound' and in_out != 'outbound':
            self.logger.exception("Illegal argument to update_policies: " + in_out)
            raise
        if in_out in self.policies:
            to_remove = [x['cookie'] for x in self.policies[in_out] if x['cookie'] in cookies]
            self.policies[in_out] = [x for x in self.policies[in_out] if x['cookie'] not in cookies]
            self.logger.debug('removed cookies: ' + str(to_remove) + ' from: ' + in_out)
            return to_remove
        return []

    def queue_flow_removals(self, cookies, in_out):
        removal_msgs = []
        for cookie in cookies:
            mod =  {"rule_type":in_out,
                    "cookie":(cookie,2**16-1), "mod_type":"remove"}
            removal_msgs.append(mod)
        self.logger.debug('queue_flow_removals: ' + str(removal_msgs))
        self.dp_queued.extend(removal_msgs)
            

    def process_policy_changes(self, change_info):
        if not self.cfg.isSupersetsMode():
            self.logger.warn('Dynamic policy updates only supported in SuperSet mode')
            return

        # First step towards a less brute force approach: Handle removals without having to remove everything
        if 'removal_cookies' in change_info:
            cookies = change_info['removal_cookies']
            removed_in_cookies = self.remove_policies_by_cookies(cookies, 'inbound')
            self.queue_flow_removals(removed_in_cookies, 'inbound')
            removed_out_cookies = self.remove_policies_by_cookies(cookies, 'outbound')
            self.queue_flow_removals(removed_out_cookies, 'outbound')
            if not 'new_policies' in change_info:
                self.push_dp()
                return

        # Remainder of this method is brute force approach: wipe everything and re-do it
        # This should be replaced by a more fine grained approach
        self.logger.debug("Wiping outbound rules.")
        wipe_msgs = msg_clear_all_outbound(self.policies, self.port0_mac)
        self.dp_queued.extend(wipe_msgs)

        self.logger.debug("pre-updated policies: " + json.dumps(self.policies))
        if 'removal_cookies' in change_info:
            cookies = change_info['removal_cookies']
            self.remove_policies_by_cookies(cookies, 'inbound')
            self.remove_policies_by_cookies(cookies, 'outbound')

        if 'new_policies' in change_info:
            new_policies = change_info['new_policies']
            self.sanitize_policies(new_policies)
            self.update_policies(new_policies, 'inbound')
            self.update_policies(new_policies, 'outbound')

        self.logger.debug("updated policies: " + json.dumps(self.policies))
        self.logger.debug("pre-recomputed supersets: " + json.dumps(self.supersets.supersets))

        self.initialize_dataplane()
        self.push_dp()

        # Send gratuitous ARP responses for all
        garp_required_vnhs = self.VNH_2_prefix.keys()
        for vnh in garp_required_vnhs:
            self.process_arp_request(None, vnh)
            
        return

        # Original code below...
        
        "Process the changes in participants' policies"
        # TODO: Implement the logic of dynamically changing participants' outbound and inbound policy
        '''
            change_info =
            {
                'removal_cookies' : [cookie1, ...], # Cookies of deleted policies
                'new_policies' :
                {
                    <policy file format>
                }

            }
        '''
        # remove flow rules for the old policies
        removal_msgs = []

        '''
        for cookie in change_info['removal_cookies']:
            mod =  {"rule_type":"outbound", "priority":0,
                    "match":match_args , "action":{},
                    "cookie":cookie, "mod_type":"remove"}
            removal_msgs.append(mod)
        '''

        self.dp_queued.extend(removal_msgs)


        # add flow rules for the new policies
        if self.cfg.isSupersetsMode():
            dp_msgs = ss_process_policy_change(self.supersets, add_policies, remove_policies, policies,
                                                self.port_count, self.port0_mac)
        else:
            dp_msgs = []

        self.dp_queued.extend(dp_msgs)

        self.push_dp()

        return 0




    def process_arp_request(self, part_mac, vnh):
        vmac = ""
        if self.cfg.isSupersetsMode():
            vmac = self.supersets.get_vmac(self, vnh)
        else:
            vmac = "whoa" # MDS vmac goes here

        arp_responses = list()

        # if this is gratuitous, send a reply to the part's ID
        if part_mac is None:
            gratuitous = True
            # set fields appropriately for gratuitous arps
            i = 0
            for port in self.cfg.ports:
                eth_dst = vmac_part_port_match(self.id, i, self.supersets, False)
                arp_responses.append({'SPA': vnh, 'TPA': vnh,
                                   'SHA': vmac, 'THA': vmac,
                                   'eth_src': vmac, 'eth_dst': eth_dst})
                i += 1

        else: # if it wasn't gratuitous
            gratuitous = False
            # dig up the IP of the target participant
            for port in self.cfg.ports:
                if part_mac == port["MAC"]:
                    part_ip = port["IP"]
                    break

            # set field appropriately for arp responses
            arp_responses.append({'SPA': vnh, 'TPA': part_ip,
                        'SHA': vmac, 'THA': part_mac,
                        'eth_src': vmac, 'eth_dst': part_mac})

        if gratuitous:
            self.logger.debug("Sending Gratuitious ARP: "+str(arp_responses))
        else:
            self.logger.debug("Sending ARP Response: "+str(arp_responses))

        for arp_response in arp_responses:
            arp_response['msgType'] = 'garp'
            self.arp_client.send(arp_response)


    def getlock(self, prefixes):
        prefixes.sort()
        hsh = "-".join(prefixes)
        if hsh not in self.prefix_lock:
            #self.logger.debug("First Lock:: "+str(hsh))
            self.prefix_lock[hsh] = RLock()
        #else:
            #self.logger.debug("Repeat :: "+str(hsh))
        return self.prefix_lock[hsh]

    def process_bgp_route(self, route):
        "Process each incoming BGP advertisement"
        tstart = time.time()

        # Map to update for each prefix in the route advertisement.
        updates = self.bgp_instance.update(route)
        #self.logger.debug("process_bgp_route:: "+str(updates))
        # TODO: This step should be parallelized
        # TODO: The decision process for these prefixes is going to be same, we
        # should think about getting rid of such redundant computations.
        for update in updates:
            self.bgp_instance.decision_process_local(update)
            self.vnh_assignment(update)

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.debug("Time taken for decision process: "+str(elapsed))
            tstart = time.time()

        if self.cfg.isSupersetsMode():
            ################## SUPERSET RESPONSE TO BGP ##################
            # update supersets
            "Map the set of BGP updates to a list of superset expansions."
            ss_changes, ss_changed_prefs = self.supersets.update_supersets(self, updates)

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken to update supersets: "+str(elapsed))
                tstart = time.time()

            # ss_changed_prefs are prefixes for which the VMAC bits have changed
            # these prefixes must have gratuitous arps sent
            garp_required_vnhs = [self.prefix_2_VNH[prefix] for prefix in ss_changed_prefs]

            "If a recomputation event was needed, wipe out the flow rules."
            if ss_changes["type"] == "new":
                self.logger.debug("Wiping outbound rules.")
                wipe_msgs = msg_clear_all_outbound(self.policies, self.port0_mac)
                self.dp_queued.extend(wipe_msgs)

                #if a recomputation was needed, all VMACs must be reARPed
                # TODO: confirm reARPed is a word
                garp_required_vnhs = self.VNH_2_prefix.keys()

            if len(ss_changes['changes']) > 0:

                self.logger.debug("Supersets have changed: "+str(ss_changes))

                "Map the superset changes to a list of new flow rules."
                flow_msgs = update_outbound_rules(ss_changes, self.policies,
                        self.supersets, self.port0_mac)

                self.logger.debug("Flow msgs: "+str(flow_msgs))
                "Dump the new rules into the dataplane queue."
                self.dp_queued.extend(flow_msgs)

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken to deal with ss_changes: "+str(elapsed))
                tstart = time.time()

        ################## END SUPERSET RESPONSE ##################

        else:
            # TODO: similar logic for MDS
            self.logger.debug("Creating ctrlr messages for MDS scheme")

        self.push_dp()

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.debug("Time taken to push dp msgs: "+str(elapsed))
            tstart = time.time()

        changed_vnhs, announcements = self.bgp_instance.bgp_update_peers(updates,
                self.prefix_2_VNH, self.cfg.ports)

        """ Combine the VNHs which have changed BGP default routes with the
            VNHs which have changed supersets.
        """

        changed_vnhs = set(changed_vnhs)
        changed_vnhs.update(garp_required_vnhs)

        # Send gratuitous ARP responses for all them
        for vnh in changed_vnhs:
            self.process_arp_request(None, vnh)

        # Tell Route Server that it needs to announce these routes
        for announcement in announcements:
            # TODO: Complete the logic for this function
            self.send_announcement(announcement)

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.debug("Time taken to send garps/announcements: "+str(elapsed))
            tstart = time.time()


    def send_announcement(self, announcement):
        "Send the announcements to XRS"
	self.logger.debug("Sending announcements to XRS: %s", announcement)
	self.xrs_client.send({'msgType': 'bgp', 'announcement': announcement})


    def vnh_assignment(self, update):
        "Assign VNHs for the advertised prefixes"
        if self.cfg.isSupersetsMode():
            " Superset"
            # TODO: Do we really need to assign a VNH for each advertised prefix?
            if ('announce' in update):
                prefix = update['announce'].prefix

                if (prefix not in self.prefix_2_VNH):
                    # get next VNH and assign it the prefix
                    self.num_VNHs_in_use += 1
                    vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])

                    self.prefix_2_VNH[prefix] = vnh
                    self.VNH_2_prefix[vnh] = prefix
        else:
            "Disjoint"
            # TODO: @Robert: Place your logic here for VNH assignment for MDS scheme
            self.logger.debug("VNH assignment called for disjoint vmac_mode")


    def init_vnh_assignment(self):
        "Assign VNHs for the advertised prefixes"
        if self.cfg.isSupersetsMode():
            " Superset"
            # TODO: Do we really need to assign a VNH for each advertised prefix?
            #self.bgp_instance.rib["local"].dump()
            prefixes = self.bgp_instance.rib["local"].get_prefixes()
            #print 'init_vnh_assignment: prefixes:', prefixes
            #print 'init_vnh_assignment: prefix_2_VNH:', self.prefix_2_VNH
            for prefix in prefixes:
                if (prefix not in self.prefix_2_VNH):
                    # get next VNH and assign it the prefix
                    self.num_VNHs_in_use += 1
                    vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])

                    self.prefix_2_VNH[prefix] = vnh
                    self.VNH_2_prefix[vnh] = prefix
        else:
            "Disjoint"
            # TODO: @Robert: Place your logic here for VNH assignment for MDS scheme
            self.logger.debug("VNH assignment called for disjoint vmac_mode")
class ParticipantController(object):
    def __init__(self, id, config_file, policy_file, logger):
        # participant id
        self.id = id
        # print ID for logging
        self.logger = logger

        # used to signal termination
        self.run = True
        self.prefix_lock = {}

        # Initialize participant params
        self.cfg = PConfig(config_file, self.id)
        # Vmac encoding mode
        # self.cfg.vmac_mode = config_file["vmac_mode"]
        # Dataplane mode---multi table or multi switch
        # self.cfg.dp_mode = config_file["dp_mode"]


        self.policies = self.load_policies(policy_file)

        # The port 0 MAC is used for tagging outbound rules as belonging to us
        self.port0_mac = self.cfg.port0_mac

        self.nexthop_2_part = self.cfg.get_nexthop_2_part()

        # VNHs related params
        self.num_VNHs_in_use = 0
        self.VNH_2_prefix = {}
        self.prefix_2_VNH = {}


        # Superset related params
        if self.cfg.isSupersetsMode():
            self.supersets = SuperSets(self, self.cfg.vmac_options)
        else:
            # TODO: create similar class and variables for MDS
            self.mds = None

        # Keep track of flow rules pushed
        self.dp_pushed = []
        # Keep track of flow rules which are scheduled to be pushed
        self.dp_queued = []


    def xstart(self):
        # Start all clients/listeners/whatevs
        self.logger.info("Starting controller for participant")

        # ExaBGP Peering Instance
        self.bgp_instance = self.cfg.get_bgp_instance()

        # Route server client, Reference monitor client, Arp Proxy client
        self.xrs_client = self.cfg.get_xrs_client(self.logger)
        self.xrs_client.send({'msgType': 'hello', 'id': self.cfg.id, 'peers_in': self.cfg.peers_in, 'peers_out': self.cfg.peers_out, 'ports': self.cfg.get_ports()})

        self.arp_client = self.cfg.get_arp_client(self.logger)
        self.arp_client.send({'msgType': 'hello', 'macs': self.cfg.get_macs()})

        # Participant API for dynamic route updates
        self.participant_api = self.cfg.get_participant_api(self.id, self.logger)
        self.participant_api.start(self)

        # RefMon Instance
        self.refmon_client = self.cfg.get_refmon_client(self.logger)
        
         # class for building flow mod msgs to the reference monitor
        self.fm_builder = FlowModMsgBuilder(self.id, self.refmon_client.key)

        # Send flow rules for initial policies to the SDX's Reference Monitor
        self.initialize_dataplane()
        self.push_dp()

        # Start the event handlers
        ps_thread_arp = Thread(target=self.start_eh_arp)
        ps_thread_arp.daemon = True
        ps_thread_arp.start()

        ps_thread_xrs = Thread(target=self.start_eh_xrs)
        ps_thread_xrs.daemon = True
        ps_thread_xrs.start()

        ps_thread_arp.join()
        ps_thread_xrs.join()
        self.logger.debug("Return from ps_thread.join()")

    def sanitize_policies(self, policies):

        port_count = len(self.cfg.ports)

        # sanitize the input policies
        if 'inbound' in policies:
            for policy in policies['inbound']:
                if 'action' not in policy:
                    continue
                if 'fwd' in policy['action'] and int(policy['action']['fwd']) >= port_count:
                    policy['action']['fwd'] = 0

        return policies


    def load_policies(self, policy_file):
        # Load policies from file

        with open(policy_file, 'r') as f:
            policies = json.load(f)

        return self.sanitize_policies(policies)


    def initialize_dataplane(self):
        "Read the config file and update the queued policy variable"

        self.logger.info("Initializing inbound rules")

        final_switch = "main-in"
        if self.cfg.isMultiTableMode():
            final_switch = "main-out"

        self.init_vnh_assignment()

        rule_msgs = init_inbound_rules(self.id, self.policies,
                                        self.supersets, final_switch)
        self.logger.debug("Rule Messages INBOUND:: "+str(rule_msgs))

        rule_msgs2 = init_outbound_rules(self, self.id, self.policies,
                                        self.supersets, final_switch)
        self.logger.debug("Rule Messages OUTBOUND:: "+str(rule_msgs2))

        if 'changes' in rule_msgs2:
            if 'changes' not in rule_msgs:
                rule_msgs['changes'] = []
            rule_msgs['changes'] += rule_msgs2['changes']

        #TODO: Initialize Outbound Policies from RIB
        self.logger.debug("Rule Messages:: "+str(rule_msgs))
        if 'changes' in rule_msgs:
            self.dp_queued.extend(rule_msgs["changes"])


    def push_dp(self):
        '''
        (1) Check if there are any policies queued to be pushed
        (2) Send the queued policies to reference monitor
        '''

        # it is crucial that dp_queued is traversed chronologically
        for flowmod in self.dp_queued:
            self.fm_builder.add_flow_mod(**flowmod)
            self.dp_pushed.append(flowmod)

        # reset queue
        self.dp_queued = []

        self.refmon_client.send(json.dumps(self.fm_builder.get_msg()))
        
        # reset flow_mods after send - self.flow_mods = []
        self.fm_builder.reset_flow_mod()


    def stop(self):
        "Stop the Participants' SDN Controller"

        self.logger.info("Stopping Controller.")

        # Signal Termination and close blocking listener
        self.run = False

        # TODO: confirm that this isn't silly
        #self.refmon_client = None


    def start_eh_arp(self):
        self.logger.info("ARP Event Handler started.")

        while self.run:
            # need to poll since recv() will not detect close from this end
            # and need some way to shutdown gracefully.
            if not self.arp_client.poll(1):
                continue
            try:
                tmp = self.arp_client.recv()
            except EOFError:
                break

            data = json.loads(tmp)
            self.logger.debug("ARP Event received: %s", data)

            # Starting a thread for independently processing each incoming network event
            event_processor_thread = Thread(target=self.process_event, args=(data,))
            event_processor_thread.daemon = True
            event_processor_thread.start()

        self.arp_client.close()
        self.logger.debug("Exiting start_eh_arp")


    def start_eh_xrs(self):
        self.logger.info("XRS Event Handler started.")

        while self.run:
            # need to poll since recv() will not detect close from this end
            # and need some way to shutdown gracefully.
            if not self.xrs_client.poll(1):
                continue
            try:
                tmp = self.xrs_client.recv()
            except EOFError:
                break

            data = json.loads(tmp)
            self.logger.debug("XRS Event received: %s", data)

            self.process_event(data)

        self.xrs_client.close()
        self.logger.debug("Exiting start_eh_xrs")


    def process_event(self, data, mod_type=None):  
        "Locally process each incoming network event"

        if 'bgp' in data:
            self.logger.debug("Event Received: BGP Update.")
            route = data['bgp']
            # Process the incoming BGP updates from XRS
            #self.logger.debug("BGP Route received: "+str(route)+" "+str(type(route)))
            self.process_bgp_route(route)

        elif 'policy' in data:
            # Process the event requesting change of participants' policies
            self.logger.debug("Event Received: Policy change.")
            change_info = data['policy']
            for element in change_info:
                if 'remove' in element:
                    self.process_policy_changes(element['remove'], 'remove')
                    #self.logger.debug("PART_Test: REMOVE: %s" % element)
                if 'insert' in element:
                    self.process_policy_changes(element['insert'], 'insert')
                    #self.logger.debug("PART_Test: INSERT: %s" % element)

        elif 'arp' in data:
            (requester_srcmac, requested_vnh) = tuple(data['arp'])
            self.logger.debug("Event Received: ARP request for IP "+str(requested_vnh))
            self.process_arp_request(requester_srcmac, requested_vnh)

        else:
            self.logger.warn("UNKNOWN EVENT TYPE RECEIVED: "+str(data))


    def process_policy_changes(self, change_info, mod_type):
        # idea to remove flow rules for the old policies with cookies
        '''
        removal_msgs = []
        for element in change_info:

            if 'removal_cookies' in element:
        
                for cookie in element['removal_cookies']:
                    cookie_id = (cookie['cookie'],65535)
                    match_args = cookie['match']
                    mod =  {"rule_type":"inbound", "priority":4,"match":{} , "action":{}, "cookie":cookie_id, "mod_type":"remove"}
                    removal_msgs.append(mod)
        
        self.dp_queued.extend(removal_msgs)
        '''

        # json file format for change_info - mod_type = remove or insert
        '''
        {
            "policy": [
            {
                mod_type: [ 
        
        # change_info begin

                    {
                        "inbound": [
                            { cookie1 ... match ... action }
                            { cookie2 ... match ... action }
                        ]
                    }

                    {
                        "outbound": [
                            { cookie1 ... match ... action }
                            { cookie2 ... match ... action }
                        ]
                    }

        # change_info end
                
                ]           // end mod_type-array
            }, 
            
            {
                mod_type: ...

            }

            ]               // end policy-array
        }
        '''

        policies = self.sanitize_policies(change_info)

        final_switch = "main-in"
        if self.cfg.isMultiTableMode():
            final_switch = "main-out"

        #self.init_vnh_assignment() // not used
        inbound_policies = {}
        outbound_policies = {}
        
        for element in policies:
            if 'inbound' in element:
                inbound_policies = element
            if 'outbound' in element:
                outbound_policies = element

        #self.logger.debug("PART_Test: INBOUND: %s" % inbound_policies)
        #self.logger.debug("PART_Test: OUTBOUND: %s" % outbound_policies)

        rule_msgs = init_inbound_rules(self.id, inbound_policies,
                                        self.supersets, final_switch)

        rule_msgs2 = init_outbound_rules(self, self.id, outbound_policies,
                                        self.supersets, final_switch)

        if 'changes' in rule_msgs2:
            if 'changes' not in rule_msgs:
                rule_msgs['changes'] = []
            rule_msgs['changes'] += rule_msgs2['changes']


        for rule in rule_msgs['changes']:
            rule['mod_type'] = mod_type


        #self.logger.debug("PART_Test: Rule Msgs: %s" % rule_msgs)

        if 'changes' in rule_msgs:
            self.dp_queued.extend(rule_msgs["changes"])

        self.push_dp()


    def process_arp_request(self, part_mac, vnh):
        vmac = ""
        if self.cfg.isSupersetsMode():
            vmac = self.supersets.get_vmac(self, vnh)
        else:
            vmac = "whoa" # MDS vmac goes here

        arp_responses = list()

        # if this is gratuitous, send a reply to the part's ID
        if part_mac is None:
            gratuitous = True
            # set fields appropriately for gratuitous arps
            i = 0
            for port in self.cfg.ports:
                eth_dst = vmac_part_port_match(self.id, i, self.supersets, False)
                arp_responses.append({'SPA': vnh, 'TPA': vnh,
                                   'SHA': vmac, 'THA': vmac,
                                   'eth_src': vmac, 'eth_dst': eth_dst})
                i += 1

        else: # if it wasn't gratuitous
            gratuitous = False
            # dig up the IP of the target participant
            for port in self.cfg.ports:
                if part_mac == port["MAC"]:
                    part_ip = port["IP"]
                    break

            # set field appropriately for arp responses
            arp_responses.append({'SPA': vnh, 'TPA': part_ip,
                        'SHA': vmac, 'THA': part_mac,
                        'eth_src': vmac, 'eth_dst': part_mac})

        if gratuitous:
            self.logger.debug("Sending Gratuitious ARP: "+str(arp_responses))
        else:
            self.logger.debug("Sending ARP Response: "+str(arp_responses))

        for arp_response in arp_responses:
            arp_response['msgType'] = 'garp'
            self.arp_client.send(arp_response)


    def getlock(self, prefixes):
        prefixes.sort()
        hsh = "-".join(prefixes)
        if hsh not in self.prefix_lock:
            #self.logger.debug("First Lock:: "+str(hsh))
            self.prefix_lock[hsh] = RLock()
        #else:
            #self.logger.debug("Repeat :: "+str(hsh))
        return self.prefix_lock[hsh]

    def process_bgp_route(self, route):
        "Process each incoming BGP advertisement"
        tstart = time.time()

        # Map to update for each prefix in the route advertisement.
        updates = self.bgp_instance.update(route)
        #self.logger.debug("process_bgp_route:: "+str(updates))
        # TODO: This step should be parallelized
        # TODO: The decision process for these prefixes is going to be same, we
        # should think about getting rid of such redundant computations.
        for update in updates:
            self.bgp_instance.decision_process_local(update)
            self.vnh_assignment(update)

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.debug("Time taken for decision process: "+str(elapsed))
            tstart = time.time()

        if self.cfg.isSupersetsMode():
            ################## SUPERSET RESPONSE TO BGP ##################
            # update supersets
            "Map the set of BGP updates to a list of superset expansions."
            ss_changes, ss_changed_prefs = self.supersets.update_supersets(self, updates)

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken to update supersets: "+str(elapsed))
                tstart = time.time()

            # ss_changed_prefs are prefixes for which the VMAC bits have changed
            # these prefixes must have gratuitous arps sent
            garp_required_vnhs = [self.prefix_2_VNH[prefix] for prefix in ss_changed_prefs]

            "If a recomputation event was needed, wipe out the flow rules."
            if ss_changes["type"] == "new":
                self.logger.debug("Wiping outbound rules.")
                wipe_msgs = msg_clear_all_outbound(self.policies, self.port0_mac)
                self.dp_queued.extend(wipe_msgs)

                #if a recomputation was needed, all VMACs must be reARPed
                # TODO: confirm reARPed is a word
                garp_required_vnhs = self.VNH_2_prefix.keys()

            if len(ss_changes['changes']) > 0:

                self.logger.debug("Supersets have changed: "+str(ss_changes))

                "Map the superset changes to a list of new flow rules."
                flow_msgs = update_outbound_rules(ss_changes, self.policies,
                        self.supersets, self.port0_mac)

                self.logger.debug("Flow msgs: "+str(flow_msgs))
                "Dump the new rules into the dataplane queue."
                self.dp_queued.extend(flow_msgs)

            if TIMING:
                elapsed = time.time() - tstart
                self.logger.debug("Time taken to deal with ss_changes: "+str(elapsed))
                tstart = time.time()

        ################## END SUPERSET RESPONSE ##################

        else:
            # TODO: similar logic for MDS
            self.logger.debug("Creating ctrlr messages for MDS scheme")

        self.push_dp()

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.debug("Time taken to push dp msgs: "+str(elapsed))
            tstart = time.time()

        changed_vnhs, announcements = self.bgp_instance.bgp_update_peers(updates,
                self.prefix_2_VNH, self.cfg.ports)

        """ Combine the VNHs which have changed BGP default routes with the
            VNHs which have changed supersets.
        """

        changed_vnhs = set(changed_vnhs)
        changed_vnhs.update(garp_required_vnhs)

        # Send gratuitous ARP responses for all them
        for vnh in changed_vnhs:
            self.process_arp_request(None, vnh)

        # Tell Route Server that it needs to announce these routes
        for announcement in announcements:
            # TODO: Complete the logic for this function
            self.send_announcement(announcement)

        if TIMING:
            elapsed = time.time() - tstart
            self.logger.debug("Time taken to send garps/announcements: "+str(elapsed))
            tstart = time.time()


    def send_announcement(self, announcement):
        "Send the announcements to XRS"
	self.logger.debug("Sending announcements to XRS: %s", announcement)
	self.xrs_client.send({'msgType': 'bgp', 'announcement': announcement})


    def vnh_assignment(self, update):
        "Assign VNHs for the advertised prefixes"
        if self.cfg.isSupersetsMode():
            " Superset"
            # TODO: Do we really need to assign a VNH for each advertised prefix?
            if ('announce' in update):
                prefix = update['announce'].prefix

                if (prefix not in self.prefix_2_VNH):
                    # get next VNH and assign it the prefix
                    self.num_VNHs_in_use += 1
                    vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])

                    self.prefix_2_VNH[prefix] = vnh
                    self.VNH_2_prefix[vnh] = prefix
        else:
            "Disjoint"
            # TODO: @Robert: Place your logic here for VNH assignment for MDS scheme
            self.logger.debug("VNH assignment called for disjoint vmac_mode")


    def init_vnh_assignment(self):
        "Assign VNHs for the advertised prefixes"
        if self.cfg.isSupersetsMode():
            " Superset"
            # TODO: Do we really need to assign a VNH for each advertised prefix?
            #self.bgp_instance.rib["local"].dump()
            prefixes = self.bgp_instance.rib["local"].get_prefixes()
            #print 'init_vnh_assignment: prefixes:', prefixes
            #print 'init_vnh_assignment: prefix_2_VNH:', self.prefix_2_VNH
            for prefix in prefixes:
                if (prefix not in self.prefix_2_VNH):
                    # get next VNH and assign it the prefix
                    self.num_VNHs_in_use += 1
                    vnh = str(self.cfg.VNHs[self.num_VNHs_in_use])

                    self.prefix_2_VNH[prefix] = vnh
                    self.VNH_2_prefix[vnh] = prefix
        else:
            "Disjoint"
            # TODO: @Robert: Place your logic here for VNH assignment for MDS scheme
            self.logger.debug("VNH assignment called for disjoint vmac_mode")