971 lines
35 KiB
Python
971 lines
35 KiB
Python
# Copyright (C) 2014 Xinguard, Inc.
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# Copyright (C) 2013 Nippon Telegraph and Telephone Corporation.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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Implementation of Bidirectional Forwarding Detection for IPv4 (Single Hop)
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This module provides a simple way to let OSKen act like a daemon for running
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IPv4 single hop BFD (RFC5881).
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Please note that:
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* Demand mode and echo function are not yet supported.
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* Mechanism on negotiating L2/L3 addresses for an established
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session is not yet implemented.
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* The interoperability of authentication support is not tested.
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* Configuring a BFD session with too small interval may lead to
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full of event queue and congestion of Openflow channels.
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For deploying a low-latency configuration or with a large number
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of BFD sessions, use standalone BFD daemon instead.
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"""
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import logging
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import time
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import random
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import six
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from os_ken.base import app_manager
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from os_ken.controller import event
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from os_ken.controller import ofp_event
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from os_ken.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER
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from os_ken.controller.handler import set_ev_cls
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from os_ken.exception import OSKenException
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from os_ken.ofproto.ether import ETH_TYPE_IP, ETH_TYPE_ARP
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from os_ken.ofproto import ofproto_v1_3
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from os_ken.ofproto import inet
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from os_ken.lib import hub
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from os_ken.lib.packet import packet
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from os_ken.lib.packet import ethernet
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from os_ken.lib.packet import ipv4
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from os_ken.lib.packet import udp
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from os_ken.lib.packet import bfd
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from os_ken.lib.packet import arp
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from os_ken.lib.packet.arp import ARP_REQUEST, ARP_REPLY
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LOG = logging.getLogger(__name__)
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UINT16_MAX = (1 << 16) - 1
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UINT32_MAX = (1 << 32) - 1
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# RFC5881 Section 8
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BFD_CONTROL_UDP_PORT = 3784
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BFD_ECHO_UDP_PORT = 3785
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class BFDSession(object):
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"""BFD Session class.
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An instance maintains a BFD session.
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"""
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def __init__(self, app, my_discr, dpid, ofport,
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src_mac, src_ip, src_port,
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dst_mac="FF:FF:FF:FF:FF:FF", dst_ip="255.255.255.255",
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detect_mult=3,
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desired_min_tx_interval=1000000,
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required_min_rx_interval=1000000,
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auth_type=0, auth_keys=None):
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"""
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Initialize a BFD session.
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__init__ takes the corresponding args in this order.
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.. tabularcolumns:: |l|L|
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========================= ============================================
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Argument Description
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========================= ============================================
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app The instance of BFDLib.
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my_discr My Discriminator.
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dpid Datapath ID of the BFD interface.
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ofport Openflow port number of the BFD interface.
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src_mac Source MAC address of the BFD interface.
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src_ip Source IPv4 address of the BFD interface.
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dst_mac (Optional) Destination MAC address of the
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BFD interface.
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dst_ip (Optional) Destination IPv4 address of the
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BFD interface.
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detect_mult (Optional) Detection time multiplier.
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desired_min_tx_interval (Optional) Desired Min TX Interval.
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(in microseconds)
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required_min_rx_interval (Optional) Required Min RX Interval.
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(in microseconds)
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auth_type (Optional) Authentication type.
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auth_keys (Optional) A dictionary of authentication
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key chain which key is an integer of
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*Auth Key ID* and value is a string of
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*Password* or *Auth Key*.
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========================= ============================================
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Example::
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sess = BFDSession(app=self.bfdlib,
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my_discr=1,
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dpid=1,
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ofport=1,
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src_mac="01:23:45:67:89:AB",
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src_ip="192.168.1.1",
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dst_mac="12:34:56:78:9A:BC",
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dst_ip="192.168.1.2",
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detect_mult=3,
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desired_min_tx_interval=1000000,
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required_min_rx_interval=1000000,
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auth_type=bfd.BFD_AUTH_KEYED_SHA1,
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auth_keys={1: "secret key 1",
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2: "secret key 2"})
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"""
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auth_keys = auth_keys if auth_keys else {}
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assert not (auth_type and len(auth_keys) == 0)
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# OSKenApp reference to BFDLib
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self.app = app
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# RFC5880 Section 6.8.1.
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# BFD Internal Variables
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self._session_state = bfd.BFD_STATE_DOWN
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self._remote_session_state = bfd.BFD_STATE_DOWN
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self._local_discr = my_discr
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self._remote_discr = 0
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self._local_diag = 0
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self._desired_min_tx_interval = 1000000
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self._required_min_rx_interval = required_min_rx_interval
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self._remote_min_rx_interval = -1
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# TODO: Demand mode is not yet supported.
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self._demand_mode = 0
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self._remote_demand_mode = 0
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self._detect_mult = detect_mult
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self._auth_type = auth_type
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self._auth_keys = auth_keys
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if self._auth_type in [bfd.BFD_AUTH_KEYED_MD5,
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bfd.BFD_AUTH_METICULOUS_KEYED_MD5,
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bfd.BFD_AUTH_KEYED_SHA1,
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bfd.BFD_AUTH_METICULOUS_KEYED_SHA1]:
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self._rcv_auth_seq = 0
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self._xmit_auth_seq = random.randint(0, UINT32_MAX)
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self._auth_seq_known = 0
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# BFD Runtime Variables
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self._cfg_desired_min_tx_interval = desired_min_tx_interval
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self._cfg_required_min_echo_rx_interval = 0
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self._active_role = True
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self._detect_time = 0
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self._xmit_period = None
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self._update_xmit_period()
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self._is_polling = True
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self._pending_final = False
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# _enable_send indicates the switch of the periodic transmission of
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# BFD Control packets.
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self._enable_send = True
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self._lock = None
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# L2/L3/L4 Header fields
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self.src_mac = src_mac
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self.dst_mac = dst_mac
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self.src_ip = src_ip
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self.dst_ip = dst_ip
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self.ipv4_id = random.randint(0, UINT16_MAX)
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self.src_port = src_port
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self.dst_port = BFD_CONTROL_UDP_PORT
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if dst_mac == "FF:FF:FF:FF:FF:FF" or dst_ip == "255.255.255.255":
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self._remote_addr_config = False
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else:
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self._remote_addr_config = True
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# Switch and port associated to this BFD session.
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self.dpid = dpid
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self.datapath = None
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self.ofport = ofport
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# Spawn a periodic transmission loop for BFD Control packets.
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hub.spawn(self._send_loop)
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LOG.info("[BFD][%s][INIT] BFD Session initialized.",
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hex(self._local_discr))
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@property
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def my_discr(self):
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"""
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Returns My Discriminator of the BFD session.
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"""
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return self._local_discr
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@property
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def your_discr(self):
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"""
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Returns Your Discriminator of the BFD session.
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"""
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return self._remote_discr
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def set_remote_addr(self, dst_mac, dst_ip):
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"""
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Configure remote ethernet and IP addresses.
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"""
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self.dst_mac = dst_mac
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self.dst_ip = dst_ip
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if not (dst_mac == "FF:FF:FF:FF:FF:FF" or dst_ip == "255.255.255.255"):
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self._remote_addr_config = True
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LOG.info("[BFD][%s][REMOTE] Remote address configured: %s, %s.",
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hex(self._local_discr), self.dst_ip, self.dst_mac)
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def recv(self, bfd_pkt):
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"""
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BFD packet receiver.
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"""
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LOG.debug("[BFD][%s][RECV] BFD Control received: %s",
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hex(self._local_discr), six.binary_type(bfd_pkt))
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self._remote_discr = bfd_pkt.my_discr
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self._remote_state = bfd_pkt.state
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self._remote_demand_mode = bfd_pkt.flags & bfd.BFD_FLAG_DEMAND
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if self._remote_min_rx_interval != bfd_pkt.required_min_rx_interval:
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self._remote_min_rx_interval = bfd_pkt.required_min_rx_interval
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# Update transmit interval (RFC5880 Section 6.8.2.)
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self._update_xmit_period()
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# TODO: Echo function (RFC5880 Page 35)
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if bfd_pkt.flags & bfd.BFD_FLAG_FINAL and self._is_polling:
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self._is_polling = False
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# Check and update the session state (RFC5880 Page 35)
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if self._session_state == bfd.BFD_STATE_ADMIN_DOWN:
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return
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if bfd_pkt.state == bfd.BFD_STATE_ADMIN_DOWN:
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if self._session_state != bfd.BFD_STATE_DOWN:
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self._set_state(bfd.BFD_STATE_DOWN,
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bfd.BFD_DIAG_NEIG_SIG_SESS_DOWN)
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else:
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if self._session_state == bfd.BFD_STATE_DOWN:
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if bfd_pkt.state == bfd.BFD_STATE_DOWN:
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self._set_state(bfd.BFD_STATE_INIT)
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elif bfd_pkt.state == bfd.BFD_STATE_INIT:
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self._set_state(bfd.BFD_STATE_UP)
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elif self._session_state == bfd.BFD_STATE_INIT:
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if bfd_pkt.state in [bfd.BFD_STATE_INIT, bfd.BFD_STATE_UP]:
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self._set_state(bfd.BFD_STATE_UP)
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else:
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if bfd_pkt.state == bfd.BFD_STATE_DOWN:
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self._set_state(bfd.BFD_STATE_DOWN,
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bfd.BFD_DIAG_NEIG_SIG_SESS_DOWN)
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# TODO: Demand mode support.
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if self._remote_demand_mode and \
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self._session_state == bfd.BFD_STATE_UP and \
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self._remote_session_state == bfd.BFD_STATE_UP:
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self._enable_send = False
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if not self._remote_demand_mode or \
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self._session_state != bfd.BFD_STATE_UP or \
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self._remote_session_state != bfd.BFD_STATE_UP:
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if not self._enable_send:
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self._enable_send = True
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hub.spawn(self._send_loop)
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# Update the detection time (RFC5880 Section 6.8.4.)
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if self._detect_time == 0:
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self._detect_time = bfd_pkt.desired_min_tx_interval * \
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bfd_pkt.detect_mult / 1000000.0
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# Start the timeout loop.
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hub.spawn(self._recv_timeout_loop)
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if bfd_pkt.flags & bfd.BFD_FLAG_POLL:
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self._pending_final = True
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self._detect_time = bfd_pkt.desired_min_tx_interval * \
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bfd_pkt.detect_mult / 1000000.0
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# Update the remote authentication sequence number.
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if self._auth_type in [bfd.BFD_AUTH_KEYED_MD5,
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bfd.BFD_AUTH_METICULOUS_KEYED_MD5,
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bfd.BFD_AUTH_KEYED_SHA1,
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bfd.BFD_AUTH_METICULOUS_KEYED_SHA1]:
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self._rcv_auth_seq = bfd_pkt.auth_cls.seq
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self._auth_seq_known = 1
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# Set the lock.
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if self._lock is not None:
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self._lock.set()
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def _set_state(self, new_state, diag=None):
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"""
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Set the state of the BFD session.
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"""
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old_state = self._session_state
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LOG.info("[BFD][%s][STATE] State changed from %s to %s.",
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hex(self._local_discr),
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bfd.BFD_STATE_NAME[old_state],
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bfd.BFD_STATE_NAME[new_state])
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self._session_state = new_state
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if new_state == bfd.BFD_STATE_DOWN:
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if diag is not None:
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self._local_diag = diag
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self._desired_min_tx_interval = 1000000
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self._is_polling = True
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self._update_xmit_period()
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elif new_state == bfd.BFD_STATE_UP:
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self._desired_min_tx_interval = self._cfg_desired_min_tx_interval
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self._is_polling = True
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self._update_xmit_period()
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self.app.send_event_to_observers(
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EventBFDSessionStateChanged(self, old_state, new_state))
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def _recv_timeout_loop(self):
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"""
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A loop to check timeout of receiving remote BFD packet.
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"""
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while self._detect_time:
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last_wait = time.time()
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self._lock = hub.Event()
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self._lock.wait(timeout=self._detect_time)
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if self._lock.is_set():
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# Authentication variable check (RFC5880 Section 6.8.1.)
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if getattr(self, "_auth_seq_known", 0):
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if last_wait > time.time() + 2 * self._detect_time:
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self._auth_seq_known = 0
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else:
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# Check Detection Time expiration (RFC5880 section 6.8.4.)
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LOG.info("[BFD][%s][RECV] BFD Session timed out.",
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hex(self._local_discr))
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if self._session_state not in [bfd.BFD_STATE_DOWN,
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bfd.BFD_STATE_ADMIN_DOWN]:
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self._set_state(bfd.BFD_STATE_DOWN,
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bfd.BFD_DIAG_CTRL_DETECT_TIME_EXPIRED)
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# Authentication variable check (RFC5880 Section 6.8.1.)
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if getattr(self, "_auth_seq_known", 0):
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self._auth_seq_known = 0
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def _update_xmit_period(self):
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"""
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Update transmission period of the BFD session.
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"""
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# RFC5880 Section 6.8.7.
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if self._desired_min_tx_interval > self._remote_min_rx_interval:
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xmit_period = self._desired_min_tx_interval
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else:
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xmit_period = self._remote_min_rx_interval
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# This updates the transmission period of BFD Control packets.
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# (RFC5880 Section 6.8.2 & 6.8.3.)
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if self._detect_mult == 1:
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xmit_period *= random.randint(75, 90) / 100.0
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else:
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xmit_period *= random.randint(75, 100) / 100.0
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self._xmit_period = xmit_period / 1000000.0
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LOG.info("[BFD][%s][XMIT] Transmission period changed to %f",
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hex(self._local_discr), self._xmit_period)
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def _send_loop(self):
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"""
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A loop to proceed periodic BFD packet transmission.
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"""
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while self._enable_send:
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hub.sleep(self._xmit_period)
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# Send BFD packet. (RFC5880 Section 6.8.7.)
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if self._remote_discr == 0 and not self._active_role:
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continue
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if self._remote_min_rx_interval == 0:
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continue
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if self._remote_demand_mode and \
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self._session_state == bfd.BFD_STATE_UP and \
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self._remote_session_state == bfd.BFD_STATE_UP and \
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not self._is_polling:
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continue
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self._send()
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def _send(self):
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"""
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BFD packet sender.
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"""
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# If the switch was not connected to controller, exit.
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if self.datapath is None:
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return
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# BFD Flags Setup
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flags = 0
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if self._pending_final:
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flags |= bfd.BFD_FLAG_FINAL
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self._pending_final = False
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self._is_polling = False
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if self._is_polling:
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flags |= bfd.BFD_FLAG_POLL
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# Authentication Section
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auth_cls = None
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if self._auth_type:
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auth_key_id = list(self._auth_keys.keys())[
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random.randint(0, len(list(self._auth_keys.keys())) - 1)]
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auth_key = self._auth_keys[auth_key_id]
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if self._auth_type == bfd.BFD_AUTH_SIMPLE_PASS:
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auth_cls = bfd.SimplePassword(auth_key_id=auth_key_id,
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password=auth_key)
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if self._auth_type in [bfd.BFD_AUTH_KEYED_MD5,
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bfd.BFD_AUTH_METICULOUS_KEYED_MD5,
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bfd.BFD_AUTH_KEYED_SHA1,
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bfd.BFD_AUTH_METICULOUS_KEYED_SHA1]:
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if self._auth_type in [bfd.BFD_AUTH_KEYED_MD5,
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bfd.BFD_AUTH_KEYED_SHA1]:
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if random.randint(0, 1):
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self._xmit_auth_seq = \
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(self._xmit_auth_seq + 1) & UINT32_MAX
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else:
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self._xmit_auth_seq = \
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(self._xmit_auth_seq + 1) & UINT32_MAX
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auth_cls = bfd.bfd._auth_parsers[self._auth_type](
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auth_key_id=auth_key_id,
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seq=self._xmit_auth_seq,
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auth_key=auth_key)
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if auth_cls is not None:
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flags |= bfd.BFD_FLAG_AUTH_PRESENT
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if self._demand_mode and \
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self._session_state == bfd.BFD_STATE_UP and \
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self._remote_session_state == bfd.BFD_STATE_UP:
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flags |= bfd.BFD_FLAG_DEMAND
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diag = self._local_diag
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state = self._session_state
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detect_mult = self._detect_mult
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my_discr = self._local_discr
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your_discr = self._remote_discr
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desired_min_tx_interval = self._desired_min_tx_interval
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required_min_rx_interval = self._required_min_rx_interval
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required_min_echo_rx_interval = self._cfg_required_min_echo_rx_interval
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# Prepare for Ethernet/IP/UDP header fields
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src_mac = self.src_mac
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dst_mac = self.dst_mac
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src_ip = self.src_ip
|
|
dst_ip = self.dst_ip
|
|
self.ipv4_id = (self.ipv4_id + 1) & UINT16_MAX
|
|
ipv4_id = self.ipv4_id
|
|
src_port = self.src_port
|
|
dst_port = self.dst_port
|
|
|
|
# Construct BFD Control packet
|
|
data = BFDPacket.bfd_packet(
|
|
src_mac=src_mac, dst_mac=dst_mac,
|
|
src_ip=src_ip, dst_ip=dst_ip, ipv4_id=ipv4_id,
|
|
src_port=src_port, dst_port=dst_port,
|
|
diag=diag, state=state, flags=flags, detect_mult=detect_mult,
|
|
my_discr=my_discr, your_discr=your_discr,
|
|
desired_min_tx_interval=desired_min_tx_interval,
|
|
required_min_rx_interval=required_min_rx_interval,
|
|
required_min_echo_rx_interval=required_min_echo_rx_interval,
|
|
auth_cls=auth_cls)
|
|
|
|
# Prepare for a datapath
|
|
datapath = self.datapath
|
|
ofproto = datapath.ofproto
|
|
parser = datapath.ofproto_parser
|
|
|
|
actions = [parser.OFPActionOutput(self.ofport)]
|
|
|
|
out = parser.OFPPacketOut(datapath=datapath,
|
|
buffer_id=ofproto.OFP_NO_BUFFER,
|
|
in_port=ofproto.OFPP_CONTROLLER,
|
|
actions=actions,
|
|
data=data)
|
|
|
|
datapath.send_msg(out)
|
|
LOG.debug("[BFD][%s][SEND] BFD Control sent.", hex(self._local_discr))
|
|
|
|
|
|
class BFDPacket(object):
|
|
"""
|
|
BFDPacket class for parsing raw BFD packet, and generating BFD packet with
|
|
Ethernet, IPv4, and UDP headers.
|
|
"""
|
|
|
|
class BFDUnknownFormat(OSKenException):
|
|
message = '%(msg)s'
|
|
|
|
@staticmethod
|
|
def bfd_packet(src_mac, dst_mac, src_ip, dst_ip, ipv4_id,
|
|
src_port, dst_port,
|
|
diag=0, state=0, flags=0, detect_mult=0,
|
|
my_discr=0, your_discr=0, desired_min_tx_interval=0,
|
|
required_min_rx_interval=0,
|
|
required_min_echo_rx_interval=0,
|
|
auth_cls=None):
|
|
"""
|
|
Generate BFD packet with Ethernet/IPv4/UDP encapsulated.
|
|
"""
|
|
# Generate ethernet header first.
|
|
pkt = packet.Packet()
|
|
eth_pkt = ethernet.ethernet(dst_mac, src_mac, ETH_TYPE_IP)
|
|
pkt.add_protocol(eth_pkt)
|
|
|
|
# IPv4 encapsulation
|
|
# set ToS to 192 (Network control/CS6)
|
|
# set TTL to 255 (RFC5881 Section 5.)
|
|
ipv4_pkt = ipv4.ipv4(proto=inet.IPPROTO_UDP, src=src_ip, dst=dst_ip,
|
|
tos=192, identification=ipv4_id, ttl=255)
|
|
pkt.add_protocol(ipv4_pkt)
|
|
|
|
# UDP encapsulation
|
|
udp_pkt = udp.udp(src_port=src_port, dst_port=dst_port)
|
|
pkt.add_protocol(udp_pkt)
|
|
|
|
# BFD payload
|
|
bfd_pkt = bfd.bfd(
|
|
ver=1, diag=diag, state=state, flags=flags,
|
|
detect_mult=detect_mult,
|
|
my_discr=my_discr, your_discr=your_discr,
|
|
desired_min_tx_interval=desired_min_tx_interval,
|
|
required_min_rx_interval=required_min_rx_interval,
|
|
required_min_echo_rx_interval=required_min_echo_rx_interval,
|
|
auth_cls=auth_cls)
|
|
pkt.add_protocol(bfd_pkt)
|
|
|
|
pkt.serialize()
|
|
return pkt.data
|
|
|
|
@staticmethod
|
|
def bfd_parse(data):
|
|
"""
|
|
Parse raw packet and return BFD class from packet library.
|
|
"""
|
|
pkt = packet.Packet(data)
|
|
i = iter(pkt)
|
|
eth_pkt = next(i)
|
|
|
|
assert isinstance(eth_pkt, ethernet.ethernet)
|
|
|
|
ipv4_pkt = next(i)
|
|
assert isinstance(ipv4_pkt, ipv4.ipv4)
|
|
|
|
udp_pkt = next(i)
|
|
assert isinstance(udp_pkt, udp.udp)
|
|
|
|
udp_payload = next(i)
|
|
|
|
return bfd.bfd.parser(udp_payload)[0]
|
|
|
|
|
|
class ARPPacket(object):
|
|
"""
|
|
ARPPacket class for parsing raw ARP packet, and generating ARP packet with
|
|
Ethernet header.
|
|
"""
|
|
|
|
class ARPUnknownFormat(OSKenException):
|
|
message = '%(msg)s'
|
|
|
|
@staticmethod
|
|
def arp_packet(opcode, src_mac, src_ip, dst_mac, dst_ip):
|
|
"""
|
|
Generate ARP packet with ethernet encapsulated.
|
|
"""
|
|
# Generate ethernet header first.
|
|
pkt = packet.Packet()
|
|
eth_pkt = ethernet.ethernet(dst_mac, src_mac, ETH_TYPE_ARP)
|
|
pkt.add_protocol(eth_pkt)
|
|
|
|
# Use IPv4 ARP wrapper from packet library directly.
|
|
arp_pkt = arp.arp_ip(opcode, src_mac, src_ip, dst_mac, dst_ip)
|
|
pkt.add_protocol(arp_pkt)
|
|
|
|
pkt.serialize()
|
|
return pkt.data
|
|
|
|
@staticmethod
|
|
def arp_parse(data):
|
|
"""
|
|
Parse ARP packet, return ARP class from packet library.
|
|
"""
|
|
# Iteratize pkt
|
|
pkt = packet.Packet(data)
|
|
i = iter(pkt)
|
|
eth_pkt = next(i)
|
|
# Ensure it's an ethernet frame.
|
|
assert isinstance(eth_pkt, ethernet.ethernet)
|
|
|
|
arp_pkt = next(i)
|
|
if not isinstance(arp_pkt, arp.arp):
|
|
raise ARPPacket.ARPUnknownFormat()
|
|
|
|
if arp_pkt.opcode not in (ARP_REQUEST, ARP_REPLY):
|
|
raise ARPPacket.ARPUnknownFormat(
|
|
msg='unsupported opcode %d' % arp_pkt.opcode)
|
|
|
|
if arp_pkt.proto != ETH_TYPE_IP:
|
|
raise ARPPacket.ARPUnknownFormat(
|
|
msg='unsupported arp ethtype 0x%04x' % arp_pkt.proto)
|
|
|
|
return arp_pkt
|
|
|
|
|
|
class EventBFDSessionStateChanged(event.EventBase):
|
|
"""
|
|
An event class that notifies the state change of a BFD session.
|
|
"""
|
|
|
|
def __init__(self, session, old_state, new_state):
|
|
super(EventBFDSessionStateChanged, self).__init__()
|
|
self.session = session
|
|
self.old_state = old_state
|
|
self.new_state = new_state
|
|
|
|
|
|
class BFDLib(app_manager.OSKenApp):
|
|
"""
|
|
BFD daemon library.
|
|
|
|
Add this library as a context in your app and use ``add_bfd_session``
|
|
function to establish a BFD session.
|
|
|
|
Example::
|
|
|
|
from os_ken.base import app_manager
|
|
from os_ken.controller.handler import set_ev_cls
|
|
from os_ken.ofproto import ofproto_v1_3
|
|
from os_ken.lib import bfdlib
|
|
from os_ken.lib.packet import bfd
|
|
|
|
class Foo(app_manager.OSKenApp):
|
|
OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
|
|
|
|
_CONTEXTS = {
|
|
'bfdlib': bfdlib.BFDLib
|
|
}
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
super(Foo, self).__init__(*args, **kwargs)
|
|
self.bfdlib = kwargs['bfdlib']
|
|
self.my_discr = \
|
|
self.bfdlib.add_bfd_session(dpid=1,
|
|
ofport=1,
|
|
src_mac="00:23:45:67:89:AB",
|
|
src_ip="192.168.1.1")
|
|
|
|
@set_ev_cls(bfdlib.EventBFDSessionStateChanged)
|
|
def bfd_state_handler(self, ev):
|
|
if ev.session.my_discr != self.my_discr:
|
|
return
|
|
|
|
if ev.new_state == bfd.BFD_STATE_DOWN:
|
|
print "BFD Session=%d is DOWN!" % ev.session.my_discr
|
|
elif ev.new_state == bfd.BFD_STATE_UP:
|
|
print "BFD Session=%d is UP!" % ev.session.my_discr
|
|
"""
|
|
OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
|
|
|
|
_EVENTS = [EventBFDSessionStateChanged]
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
super(BFDLib, self).__init__(*args, **kwargs)
|
|
|
|
# BFD Session Dictionary
|
|
# key: My Discriminator
|
|
# value: BFDSession object
|
|
self.session = {}
|
|
|
|
def close(self):
|
|
pass
|
|
|
|
@set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
|
|
def switch_features_handler(self, ev):
|
|
datapath = ev.msg.datapath
|
|
ofproto = datapath.ofproto
|
|
parser = datapath.ofproto_parser
|
|
|
|
# Update datapath object in BFD sessions
|
|
for s in self.session.values():
|
|
if s.dpid == datapath.id:
|
|
s.datapath = datapath
|
|
|
|
# Install default flows for capturing ARP & BFD packets.
|
|
match = parser.OFPMatch(eth_type=ETH_TYPE_ARP)
|
|
actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,
|
|
ofproto.OFPCML_NO_BUFFER)]
|
|
self.add_flow(datapath, 0xFFFF, match, actions)
|
|
|
|
match = parser.OFPMatch(eth_type=ETH_TYPE_IP,
|
|
ip_proto=inet.IPPROTO_UDP,
|
|
udp_dst=3784)
|
|
actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,
|
|
ofproto.OFPCML_NO_BUFFER)]
|
|
self.add_flow(datapath, 0xFFFF, match, actions)
|
|
|
|
def add_flow(self, datapath, priority, match, actions):
|
|
ofproto = datapath.ofproto
|
|
parser = datapath.ofproto_parser
|
|
|
|
inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS,
|
|
actions)]
|
|
|
|
mod = parser.OFPFlowMod(datapath=datapath, priority=priority,
|
|
match=match, instructions=inst)
|
|
datapath.send_msg(mod)
|
|
|
|
# Packet-In Handler, only for BFD packets.
|
|
@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
|
|
def _packet_in_handler(self, ev):
|
|
msg = ev.msg
|
|
datapath = msg.datapath
|
|
ofproto = datapath.ofproto
|
|
parser = datapath.ofproto_parser
|
|
in_port = msg.match['in_port']
|
|
|
|
pkt = packet.Packet(msg.data)
|
|
|
|
# If there's someone asked for an IP address associated
|
|
# with a BFD session, generate an ARP reply for it.
|
|
if arp.arp in pkt:
|
|
arp_pkt = ARPPacket.arp_parse(msg.data)
|
|
if arp_pkt.opcode == ARP_REQUEST:
|
|
for s in self.session.values():
|
|
if s.dpid == datapath.id and \
|
|
s.ofport == in_port and \
|
|
s.src_ip == arp_pkt.dst_ip:
|
|
|
|
ans = ARPPacket.arp_packet(
|
|
ARP_REPLY,
|
|
s.src_mac, s.src_ip,
|
|
arp_pkt.src_mac, arp_pkt.src_ip)
|
|
|
|
actions = [parser.OFPActionOutput(in_port)]
|
|
out = parser.OFPPacketOut(
|
|
datapath=datapath,
|
|
buffer_id=ofproto.OFP_NO_BUFFER,
|
|
in_port=ofproto.OFPP_CONTROLLER,
|
|
actions=actions, data=ans)
|
|
|
|
datapath.send_msg(out)
|
|
return
|
|
return
|
|
|
|
# Check whether it's BFD packet or not.
|
|
if ipv4.ipv4 not in pkt or udp.udp not in pkt:
|
|
return
|
|
|
|
udp_hdr = pkt.get_protocols(udp.udp)[0]
|
|
if udp_hdr.dst_port != BFD_CONTROL_UDP_PORT:
|
|
return
|
|
|
|
# Parse BFD packet here.
|
|
self.recv_bfd_pkt(datapath, in_port, msg.data)
|
|
|
|
def add_bfd_session(self, dpid, ofport, src_mac, src_ip,
|
|
dst_mac="FF:FF:FF:FF:FF:FF", dst_ip="255.255.255.255",
|
|
auth_type=0, auth_keys=None):
|
|
"""
|
|
Establish a new BFD session and return My Discriminator of new session.
|
|
|
|
Configure the BFD session with the following arguments.
|
|
|
|
================ ======================================================
|
|
Argument Description
|
|
================ ======================================================
|
|
dpid Datapath ID of the BFD interface.
|
|
ofport Openflow port number of the BFD interface.
|
|
src_mac Source MAC address of the BFD interface.
|
|
src_ip Source IPv4 address of the BFD interface.
|
|
dst_mac (Optional) Destination MAC address of the BFD
|
|
interface.
|
|
dst_ip (Optional) Destination IPv4 address of the BFD
|
|
interface.
|
|
auth_type (Optional) Authentication type.
|
|
auth_keys (Optional) A dictionary of authentication key chain
|
|
which key is an integer of *Auth Key ID* and value
|
|
is a string of *Password* or *Auth Key*.
|
|
================ ======================================================
|
|
|
|
Example::
|
|
|
|
add_bfd_session(dpid=1,
|
|
ofport=1,
|
|
src_mac="01:23:45:67:89:AB",
|
|
src_ip="192.168.1.1",
|
|
dst_mac="12:34:56:78:9A:BC",
|
|
dst_ip="192.168.1.2",
|
|
auth_type=bfd.BFD_AUTH_KEYED_SHA1,
|
|
auth_keys={1: "secret key 1",
|
|
2: "secret key 2"})
|
|
"""
|
|
auth_keys = auth_keys if auth_keys else {}
|
|
# Generate a unique discriminator
|
|
while True:
|
|
# Generate My Discriminator
|
|
my_discr = random.randint(1, UINT32_MAX)
|
|
|
|
# Generate an UDP destination port according to RFC5881 Section 4.
|
|
src_port = random.randint(49152, 65535)
|
|
|
|
# Ensure generated discriminator and UDP port are unique.
|
|
if my_discr in self.session:
|
|
continue
|
|
|
|
unique_flag = True
|
|
|
|
for s in self.session.values():
|
|
if s.your_discr == my_discr or s.src_port == src_port:
|
|
unique_flag = False
|
|
break
|
|
|
|
if unique_flag:
|
|
break
|
|
|
|
sess = BFDSession(app=self, my_discr=my_discr,
|
|
dpid=dpid, ofport=ofport,
|
|
src_mac=src_mac, src_ip=src_ip, src_port=src_port,
|
|
dst_mac=dst_mac, dst_ip=dst_ip,
|
|
auth_type=auth_type, auth_keys=auth_keys)
|
|
|
|
self.session[my_discr] = sess
|
|
|
|
return my_discr
|
|
|
|
def recv_bfd_pkt(self, datapath, in_port, data):
|
|
pkt = packet.Packet(data)
|
|
eth = pkt.get_protocols(ethernet.ethernet)[0]
|
|
|
|
if eth.ethertype != ETH_TYPE_IP:
|
|
return
|
|
|
|
ip_pkt = pkt.get_protocols(ipv4.ipv4)[0]
|
|
|
|
# Discard it if TTL != 255 for single hop bfd. (RFC5881 Section 5.)
|
|
if ip_pkt.ttl != 255:
|
|
return
|
|
|
|
# Parse BFD packet here.
|
|
bfd_pkt = BFDPacket.bfd_parse(data)
|
|
|
|
if not isinstance(bfd_pkt, bfd.bfd):
|
|
return
|
|
|
|
# BFD sanity checks
|
|
# RFC 5880 Section 6.8.6.
|
|
if bfd_pkt.ver != 1:
|
|
return
|
|
|
|
if bfd_pkt.flags & bfd.BFD_FLAG_AUTH_PRESENT:
|
|
if bfd_pkt.length < 26:
|
|
return
|
|
else:
|
|
if bfd_pkt.length < 24:
|
|
return
|
|
|
|
if bfd_pkt.detect_mult == 0:
|
|
return
|
|
|
|
if bfd_pkt.flags & bfd.BFD_FLAG_MULTIPOINT:
|
|
return
|
|
|
|
if bfd_pkt.my_discr == 0:
|
|
return
|
|
|
|
if bfd_pkt.your_discr != 0 and bfd_pkt.your_discr not in self.session:
|
|
return
|
|
|
|
if bfd_pkt.your_discr == 0 and \
|
|
bfd_pkt.state not in [bfd.BFD_STATE_ADMIN_DOWN,
|
|
bfd.BFD_STATE_DOWN]:
|
|
return
|
|
|
|
sess_my_discr = None
|
|
|
|
if bfd_pkt.your_discr == 0:
|
|
# Select session (Page 34)
|
|
for s in self.session.values():
|
|
if s.dpid == datapath.id and s.ofport == in_port:
|
|
sess_my_discr = s.my_discr
|
|
break
|
|
|
|
# BFD Session not found.
|
|
if sess_my_discr is None:
|
|
return
|
|
else:
|
|
sess_my_discr = bfd_pkt.your_discr
|
|
|
|
sess = self.session[sess_my_discr]
|
|
|
|
if bfd_pkt.flags & bfd.BFD_FLAG_AUTH_PRESENT and sess._auth_type == 0:
|
|
return
|
|
|
|
if bfd_pkt.flags & bfd.BFD_FLAG_AUTH_PRESENT == 0 and \
|
|
sess._auth_type != 0:
|
|
return
|
|
|
|
# Authenticate the session (Section 6.7.)
|
|
if bfd_pkt.flags & bfd.BFD_FLAG_AUTH_PRESENT:
|
|
if sess._auth_type == 0:
|
|
return
|
|
|
|
if bfd_pkt.auth_cls.auth_type != sess._auth_type:
|
|
return
|
|
|
|
# Check authentication sequence number to defend replay attack.
|
|
if sess._auth_type in [bfd.BFD_AUTH_KEYED_MD5,
|
|
bfd.BFD_AUTH_METICULOUS_KEYED_MD5,
|
|
bfd.BFD_AUTH_KEYED_SHA1,
|
|
bfd.BFD_AUTH_METICULOUS_KEYED_SHA1]:
|
|
if sess._auth_seq_known:
|
|
if bfd_pkt.auth_cls.seq < sess._rcv_auth_seq:
|
|
return
|
|
|
|
if sess._auth_type in [bfd.BFD_AUTH_METICULOUS_KEYED_MD5,
|
|
bfd.BFD_AUTH_METICULOUS_KEYED_SHA1]:
|
|
if bfd_pkt.auth_cls.seq <= sess._rcv_auth_seq:
|
|
return
|
|
|
|
if bfd_pkt.auth_cls.seq > sess._rcv_auth_seq \
|
|
+ 3 * sess._detect_mult:
|
|
return
|
|
|
|
if not bfd_pkt.authenticate(sess._auth_keys):
|
|
LOG.debug("[BFD][%s][AUTH] BFD Control authentication failed.",
|
|
hex(sess._local_discr))
|
|
return
|
|
|
|
# Sanity check passed, proceed.
|
|
if sess is not None:
|
|
# Check whether L2/L3 addresses were configured or not.
|
|
# TODO: L2/L3 addresses negotiation for an established session.
|
|
if not sess._remote_addr_config:
|
|
sess.set_remote_addr(eth.src, ip_pkt.src)
|
|
# Proceed to session update.
|
|
sess.recv(bfd_pkt)
|