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# encoding: utf-8 |
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""" |
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sradjlan.py |
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Created by Evelio Vila |
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Copyright (c) 2014-2017 Exa Networks. All rights reserved. |
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""" |
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import json |
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from struct import unpack |
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from exabgp.util import hexstring |
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from exabgp.protocol.iso import ISO |
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from exabgp.bgp.message.update.attribute.bgpls.linkstate import LinkState |
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from exabgp.bgp.message.update.attribute.bgpls.linkstate import FlagLS |
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# 0 1 2 3 |
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# 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 |
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# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
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# | Type | Length | |
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# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
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# | Flags | Weight | Reserved | |
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# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
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# |
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# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
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# | OSPF Neighbor ID / IS-IS System-ID | |
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# + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
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# | | |
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# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
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# |
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# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
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# | SID/Label/Index (variable) | |
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# +---------------------------------------------------------------+ |
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# draft-gredler-idr-bgp-ls-segment-routing-ext-03 |
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# draft-ietf-isis-segment-routing-extensions - Adj-SID IS-IS Flags |
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@LinkState.register() |
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class SrAdjacencyLan(FlagLS): |
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TLV = 1100 |
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FLAGS = ['F', 'B', 'V', 'L', 'S', 'P', 'RSV', 'RSV'] |
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MERGE = True |
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def __init__(self, sradjlans): |
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self.sr_adj_lan_sids = [] |
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def __repr__(self): |
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return "sr-adj-lan-sids: {}".format(self.sr_adj_lan_sids) |
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@classmethod |
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def unpack(cls, data, length): |
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# We only support IS-IS flags for now. |
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flags = cls.unpack_flags(data[0:1]) |
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# Parse adj weight |
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weight = data[1] |
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# Move pointer 4 bytes: Flags(1) + Weight(1) + Reserved(2) |
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system_id = ISO.unpack_sysid(data[4:10]) |
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data = data[10:] |
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# SID/Index/Label: according to the V and L flags, it contains |
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# either: |
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# * A 3 octet local label where the 20 rightmost bits are used for |
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# encoding the label value. In this case the V and L flags MUST |
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# be set. |
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# |
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# * A 4 octet index defining the offset in the SID/Label space |
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# advertised by this router using the encodings defined in |
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# Section 3.1. In this case V and L flags MUST be unset. |
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sids = [] |
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raw = [] |
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while data: |
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# Range Size: 3 octet value indicating the number of labels in |
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# the range. |
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if int(flags.flags['V']) and int(flags.flags['L']): |
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sid = unpack('!L', bytes([0]) + data[:3])[0] |
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data = data[3:] |
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sids.append(sid) |
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elif (not flags.flags['V']) and (not flags.flags['L']): |
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sid = unpack('!I', data[:4])[0] |
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data = data[4:] |
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sids.append(sid) |
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else: |
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raw.append(hexstring(data)) |
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break |
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return cls([{'flags': flags, 'weight': weight, 'system-id': system_id, 'sid': sid, 'undecoded': raw}]) |
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def json(self, compact=None): |
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return '"sr-adj-lan-sids": {}'.format(json.dumps(self.sr_adj_lan_sids)) |
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def merge(self, klass): |
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self.sr_adj_lan_sids.extend(klass.sr_adj_lan_sids) |
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Exa-Networks /
exabgp
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