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# encoding: utf-8
"""
igpmetric.py
Created by Evelio Vila on 2016-12-01.
Copyright (c) 2014-2017 Exa Networks. All rights reserved.
from struct import unpack
from exabgp.bgp.message.notification import Notify
from exabgp.bgp.message.update.attribute.bgpls.linkstate import LinkState
from exabgp.bgp.message.update.attribute.bgpls.linkstate import BaseLS
# The IGP Metric TLV carries the metric for this link. The length of
# this TLV is variable, depending on the metric width of the underlying
# protocol. IS-IS small metrics have a length of 1 octet (the two most
# significant bits are ignored). OSPF link metrics have a length of 2
# octets. IS-IS wide metrics have a length of 3 octets.
#
# 0 1 2 3
# 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
# | Type | Length |
# // IGP Link Metric (variable length) //
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@LinkState.register()
class IgpMetric(BaseLS):
TLV = 1095
REPR = 'IGP Metric'
JSON = 'igp-metric'
@classmethod
def unpack(cls, data, length):
if len(data) == 2:
# OSPF
return cls(unpack('!H', data)[0])
if len(data) == 1:
# ISIS small metrics
return cls(data[0])
if len(data) == 3:
# ISIS wide metrics
return cls(unpack('!L', bytes([0]) + data)[0])
raise Notify(3, 5, "Incorrect IGP Metric Size")
Exa-Networks /
exabgp
