def parse_attributes(data, asn4=False):
"""
Parses an RFC4271 encoded blob of BGP attributes into a list
:param data:
:param asn4: support 4 bytes asn or not
:return:
"""
attributes = {}
postfix = data
while len(postfix) > 0:
try:
flags, type_code = struct.unpack('!BB', postfix[:2])
if flags & AttributeFlag.EXTENDED_LENGTH:
attr_len = struct.unpack('!H', postfix[2:4])[0]
attr_value = postfix[4:4 + attr_len]
postfix = postfix[4 + attr_len:] # Next attribute
else: # standard 1-octet length
if isinstance(postfix[2], int):
attr_len = postfix[2]
else:
attr_len = ord(postfix[2])
attr_value = postfix[3:3 + attr_len]
postfix = postfix[3 + attr_len:] # Next attribute
except Exception as e:
LOG.error(e)
error_str = traceback.format_exc()
LOG.debug(error_str)
raise excep.UpdateMessageError(
sub_error=bgp_cons.ERR_MSG_UPDATE_MALFORMED_ATTR_LIST,
data='')
if type_code == bgp_cons.BGPTYPE_ORIGIN:
decode_value = Origin.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_AS_PATH:
decode_value = ASPath.parse(value=attr_value, asn4=asn4)
elif type_code == bgp_cons.BGPTYPE_NEXT_HOP:
decode_value = NextHop.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_MULTI_EXIT_DISC:
decode_value = MED.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_LOCAL_PREF:
decode_value = LocalPreference.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_ATOMIC_AGGREGATE:
decode_value = AtomicAggregate.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_AGGREGATOR:
decode_value = Aggregator.parse(value=attr_value, asn4=asn4)
elif type_code == bgp_cons.BGPTYPE_COMMUNITIES:
decode_value = Community.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_ORIGINATOR_ID:
decode_value = OriginatorID.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_CLUSTER_LIST:
decode_value = ClusterList.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_NEW_AS_PATH:
decode_value = ASPath.parse(value=attr_value, asn4=True)
elif type_code == bgp_cons.BGPTYPE_NEW_AGGREGATOR:
decode_value = Aggregator.parse(value=attr_value, asn4=True)
elif type_code == bgp_cons.BGPTYPE_MP_REACH_NLRI:
decode_value = MpReachNLRI.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_MP_UNREACH_NLRI:
decode_value = MpUnReachNLRI.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_EXTENDED_COMMUNITY:
decode_value = ExtCommunity.parse(value=attr_value)
else:
decode_value = repr(attr_value)
attributes[type_code] = decode_value
return attributes
def parse_attributes(data, asn4=False):
"""
Parses an RFC4271 encoded blob of BGP attributes into a list
:param data:
:param asn4: support 4 bytes asn or not
:return:
"""
attributes = {}
postfix = data
while len(postfix) > 0:
try:
flags, type_code = struct.unpack("!BB", postfix[:2])
if flags & AttributeFlag.EXTENDED_LENGTH:
attr_len = struct.unpack("!H", postfix[2:4])[0]
attr_value = postfix[4 : 4 + attr_len]
postfix = postfix[4 + attr_len :] # Next attribute
else: # standard 1-octet length
if isinstance(postfix[2], int):
attr_len = postfix[2]
else:
attr_len = ord(postfix[2])
attr_value = postfix[3 : 3 + attr_len]
postfix = postfix[3 + attr_len :] # Next attribute
except Exception as e:
LOG.error(e)
error_str = traceback.format_exc()
LOG.debug(error_str)
raise excep.UpdateMessageError(sub_error=bgp_cons.ERR_MSG_UPDATE_MALFORMED_ATTR_LIST, data="")
if type_code == bgp_cons.BGPTYPE_ORIGIN:
decode_value = Origin.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_AS_PATH:
decode_value = ASPath.parse(value=attr_value, asn4=asn4)
elif type_code == bgp_cons.BGPTYPE_NEXT_HOP:
decode_value = NextHop.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_MULTI_EXIT_DISC:
decode_value = MED.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_LOCAL_PREF:
decode_value = LocalPreference.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_ATOMIC_AGGREGATE:
decode_value = AtomicAggregate.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_AGGREGATOR:
decode_value = Aggregator.parse(value=attr_value, asn4=asn4)
elif type_code == bgp_cons.BGPTYPE_COMMUNITIES:
decode_value = Community.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_ORIGINATOR_ID:
decode_value = OriginatorID.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_CLUSTER_LIST:
decode_value = ClusterList.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_NEW_AS_PATH:
decode_value = ASPath.parse(value=attr_value, asn4=True)
elif type_code == bgp_cons.BGPTYPE_NEW_AGGREGATOR:
decode_value = Aggregator.parse(value=attr_value, asn4=True)
elif type_code == bgp_cons.BGPTYPE_MP_REACH_NLRI:
decode_value = MpReachNLRI.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_MP_UNREACH_NLRI:
decode_value = MpUnReachNLRI.parse(value=attr_value)
elif type_code == bgp_cons.BGPTYPE_EXTENDED_COMMUNITY:
decode_value = ExtCommunity.parse(value=attr_value)
else:
decode_value = repr(attr_value)
attributes[type_code] = decode_value
return attributes
