""" BFD protocol implementation """ from random import randint from socket import AF_INET, AF_INET6, inet_pton from scapy.all import bind_layers from scapy.layers.inet import UDP from scapy.packet import Packet from scapy.fields import BitField, BitEnumField, XByteField, FlagsField,\ ConditionalField, StrField from vpp_object import VppObject from util import NumericConstant from vpp_ip import VppIpAddress from vpp_papi import VppEnum class BFDDiagCode(NumericConstant): """ BFD Diagnostic Code """ no_diagnostic = 0 control_detection_time_expired = 1 echo_function_failed = 2 neighbor_signaled_session_down = 3 forwarding_plane_reset = 4 path_down = 5 concatenated_path_down = 6 administratively_down = 7 reverse_concatenated_path_down = 8 desc_dict = { no_diagnostic: "No diagnostic", control_detection_time_expired: "Control Detection Time Expired", echo_function_failed: "Echo Function Failed", neighbor_signaled_session_down: "Neighbor Signaled Session Down", forwarding_plane_reset: "Forwarding Plane Reset", path_down: "Path Down", concatenated_path_down: "Concatenated Path Down", administratively_down: "Administratively Down", reverse_concatenated_path_down: "Reverse Concatenated Path Down", } class BFDState(NumericConstant): """ BFD State """ admin_down = 0 down = 1 init = 2 up = 3 desc_dict = { admin_down: "AdminDown", down: "Down", init: "Init", up: "Up", } class BFDAuthType(NumericConstant): """ BFD Authentication Type """ no_auth = 0 simple_pwd = 1 keyed_md5 = 2 meticulous_keyed_md5 = 3 keyed_sha1 = 4 meticulous_keyed_sha1 = 5 desc_dict = { no_auth: "No authentication", simple_pwd: "Simple Password", keyed_md5: "Keyed MD5", meticulous_keyed_md5: "Meticulous Keyed MD5", keyed_sha1: "Keyed SHA1", meticulous_keyed_sha1: "Meticulous Keyed SHA1", } def bfd_is_auth_used(pkt): """ is packet authenticated? """ return "A" in pkt.sprintf("%BFD.flags%") def bfd_is_simple_pwd_used(pkt): """ is simple password authentication used? """ return bfd_is_auth_used(pkt) and pkt.auth_type == BFDAuthType.simple_pwd def bfd_is_sha1_used(pkt): """ is sha1 authentication used? """ return bfd_is_auth_used(pkt) and pkt.auth_type in \ (BFDAuthType.keyed_sha1, BFDAuthType.meticulous_keyed_sha1) def bfd_is_md5_used(pkt): """ is md5 authentication used? """ return bfd_is_auth_used(pkt) and pkt.auth_type in \ (BFDAuthType.keyed_md5, BFDAuthType.meticulous_keyed_md5) def bfd_is_md5_or_sha1_used(pkt): """ is md5 or sha1 used? """ return bfd_is_md5_used(pkt) or bfd_is_sha1_used(pkt) class BFD(Packet): """ BFD protocol layer for scapy """ udp_dport = 3784 #: BFD destination port per RFC 5881 udp_dport_echo = 3785 # : BFD destination port for ECHO per RFC 5881 udp_sport_min = 49152 #: BFD source port min value per RFC 5881 udp_sport_max = 65535 #: BFD source port max value per RFC 5881 bfd_pkt_len = 24 # : length of BFD pkt without authentication section sha1_auth_len = 28 # : length of authentication section if SHA1 used name = "BFD" fields_desc = [ BitField("version", 1, 3), BitEnumField("diag", 0, 5, BFDDiagCode.desc_dict), BitEnumField("state", 0, 2, BFDState.desc_dict), FlagsField("flags", 0, 6, ['M', 'D', 'A', 'C', 'F', 'P']), XByteField("detect_mult", 0), BitField("length", bfd_pkt_len, 8), BitField("my_discriminator", 0, 32), BitField("your_discriminator", 0, 32), BitField("desired_min_tx_interval", 0, 32), BitField("required_min_rx_interval", 0, 32), BitField("required_min_echo_rx_interval", 0, 32), ConditionalField( BitEnumField("auth_type", 0, 8, BFDAuthType.desc_dict), bfd_is_auth_used), ConditionalField(BitField("auth_len", 0, 8), bfd_is_auth_used), ConditionalField(BitField("auth_key_id", 0, 8), bfd_is_auth_used), ConditionalField(BitField("auth_reserved", 0, 8), bfd_is_md5_or_sha1_used), ConditionalField( BitField("auth_seq_num", 0, 32), bfd_is_md5_or_sha1_used), ConditionalField(StrField("auth_key_hash", "0" * 16), bfd_is_md5_used), ConditionalField( StrField("auth_key_hash", "0" * 20), bfd_is_sha1_used), ] def mysummary(self): return self.sprintf("BFD(my_disc=%BFD.my_discriminator%," "your_disc=%BFD.your_discriminator%)") # glue the BFD packet class to scapy parser bind_layers(UDP, BFD, dport=BFD.udp_dport) class BFD_vpp_echo(Packet): """ BFD echo packet as used by VPP (non-rfc, as rfc doesn't define one) """ udp_dport = 3785 #: BFD echo destination port per RFC 5881 name = "BFD_VPP_ECHO" fields_desc = [ BitField("discriminator", 0, 32), BitField("expire_time_clocks", 0, 64), BitField("checksum", 0, 64) ] def mysummary(self): return self.sprintf( "BFD_VPP_ECHO(disc=%BFD_VPP_ECHO.discriminator%," "expire_time_clocks=%BFD_VPP_ECHO.expire_time_clocks%)") # glue the BFD echo packet class to scapy parser bind_layers(UDP, BFD_vpp_echo, dport=BFD_vpp_echo.udp_dport) class VppBFDAuthKey(VppObject): """ Represents BFD authentication key in VPP """ def __init__(self, test, conf_key_id, auth_type, key): self._test = test self._key = key self._auth_type = auth_type test.assertIn(auth_type, BFDAuthType.desc_dict) self._conf_key_id = conf_key_id @property def test(self): """ Test which created this key """ return self._test @property def auth_type(self): """ Authentication type for this key """ return self._auth_type @property def key(self): """ key data """ return self._key @key.setter def key(self, value): self._key = value @property def conf_key_id(self): """ configuration key ID """ return self._conf_key_id def add_vpp_config(self): self.test.vapi.bfd_auth_set_key( conf_key_id=self._conf_key_id, auth_type=self._auth_type, key=self._key, key_len=len(self._key)) self._test.registry.register(self, self.test.logger) def get_bfd_auth_keys_dump_entry(self): """ get the entry in the auth keys dump corresponding to this key """ result = self.test.vapi.bfd_auth_keys_dump() for k in result: if k.conf_key_id == self._conf_key_id: return k return None def query_vpp_config(self): return self.get_bfd_auth_keys_dump_entry() is not None def remove_vpp_config(self): self.test.vapi.bfd_auth_del_key(conf_key_id=self._conf_key_id) def object_id(self): return "bfd-auth-key-%s" % self._conf_key_id class VppBFDUDPSession(VppObject): """ Represents BFD UDP session in VPP """ def __init__(self, test, interface, peer_addr, local_addr=None, af=AF_INET, desired_min_tx=300000, required_min_rx=300000, detect_mult=3, sha1_key=None, bfd_key_id=None, is_tunnel=False): self._test = test self._interface = interface self._af = af if local_addr: self._local_addr = VppIpAddress(local_addr) else: self._local_addr = None self._peer_addr = VppIpAddress(peer_addr) self._desired_min_tx = desired_min_tx self._required_min_rx = required_min_rx self._detect_mult = detect_mult self._sha1_key = sha1_key if bfd_key_id is not None: self._bfd_key_id = bfd_key_id else: self._bfd_key_id = randint(0, 255) self._is_tunnel = is_tunnel @property def test(self): """ Test which created this session """ return self._test @property def interface(self): """ Interface on which this session lives """ return self._interface @property def af(self): """ Address family - AF_INET or AF_INET6 """ return self._af @property def local_addr(self): """ BFD session local address (VPP address) """ if self._local_addr is None: if self.af == AF_INET: return self._interface.local_ip4 elif self.af == AF_INET6: return self._interface.local_ip6 else: raise Exception("Unexpected af '%s'" % self.af) return self._local_addr.address @property def peer_addr(self): """ BFD session peer address """ return self._peer_addr.address def get_bfd_udp_session_dump_entry(self): """ get the namedtuple entry from bfd udp session dump """ result = self.test.vapi.bfd_udp_session_dump() for s in result: self.test.logger.debug("session entry: %s" % str(s)) if s.sw_if_index == self.interface.sw_if_index: if self.af == AF_INET \ and self.interface.local_ip4 == str(s.local_addr) \ and self.interface.remote_ip4 == str(s.peer_addr): return s if self.af == AF_INET6 \ and self.interface.local_ip6 == str(s.local_addr) \ and self.interface.remote_ip6 == str(s.peer_addr): return s return None @property def state(self): """ BFD session state """ session = self.get_bfd_udp_session_dump_entry() if session is None: raise Exception("Could not find BFD session in VPP response") return session.state @property def desired_min_tx(self): """ desired minimum tx interval """ return self._desired_min_tx @property def required_min_rx(self): """ required minimum rx interval """ return self._required_min_rx @property def detect_mult(self): """ detect multiplier """ return self._detect_mult @property def sha1_key(self): """ sha1 key """ return self._sha1_key @property def bfd_key_id(self): """ bfd key id in use """ return self._bfd_key_id @property def is_tunnel(self): return self._is_tunnel def activate_auth(self, key, bfd_key_id=None, delayed=False): """ activate authentication for this session """ self._bfd_key_id = bfd_key_id if bfd_key_id else randint(0, 255) self._sha1_key = key conf_key_id = self._sha1_key.conf_key_id is_delayed = 1 if delayed else 0 self.test.vapi.bfd_udp_auth_activate( sw_if_index=self._interface.sw_if_index, local_addr=self.local_addr.encode(), peer_addr=self.peer_addr.encode(), bfd_key_id=self._bfd_key_id, conf_key_id=conf_key_id, is_delayed=is_delayed) def deactivate_auth(self, delayed=False): """ deactivate authentication """ self._bfd_key_id = None self._sha1_key = None is_delayed = 1 if delayed else 0 self.test.vapi.bfd_udp_auth_deactivate( sw_if_index=self._interface.sw_if_index, local_addr=self.local_addr.encode(), peer_addr=self.peer_addr.encode(), is_delayed=is_delayed) def modify_parameters(self, detect_mult=None, desired_min_tx=None, required_min_rx=None): """ modify session parameters """ if detect_mult: self._detect_mult = detect_mult if desired_min_tx: self._desired_min_tx = desired_min_tx if required_min_rx: self._required_min_rx = required_min_rx self.test.vapi.bfd_udp_mod(sw_if_index=self._interface.sw_if_index, desired_min_tx=self.desired_min_tx, required_min_rx=self.required_min_rx, detect_mult=self.detect_mult, local_addr=self.local_addr.encode(), peer_addr=self.peer_addr.encode()) def add_vpp_config(self): bfd_key_id = self._bfd_key_id if self._sha1_key else None conf_key_id = self._sha1_key.conf_key_id if self._sha1_key else None is_authenticated = True if self._sha1_key else False self.test.vapi.bfd_udp_add(sw_if_index=self._interface.sw_if_index, desired_min_tx=self.desired_min_tx, required_min_rx=self.required_min_rx, detect_mult=self.detect_mult, local_addr=self.local_addr.encode(),