|
1
|
|
|
# encoding: utf-8 |
|
2
|
|
|
""" |
|
3
|
|
|
srcap.py |
|
4
|
|
|
|
|
5
|
|
|
Created by Evelio Vila |
|
6
|
|
|
Copyright (c) 2014-2017 Exa Networks. All rights reserved. |
|
7
|
|
|
""" |
|
8
|
|
|
|
|
9
|
|
|
import json |
|
10
|
|
|
from struct import unpack |
|
11
|
|
|
|
|
12
|
|
|
from exabgp.bgp.message.update.attribute.bgpls.linkstate import LINKSTATE, LsGenericFlags |
|
13
|
|
|
from exabgp.bgp.message.notification import Notify |
|
14
|
|
|
|
|
15
|
|
|
# draft-gredler-idr-bgp-ls-segment-routing-ext-03 |
|
16
|
|
|
# 0 1 2 3 |
|
17
|
|
|
# 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 |
|
18
|
|
|
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
|
19
|
|
|
# | Type | Length | |
|
20
|
|
|
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
|
21
|
|
|
# | Flags | RESERVED | |
|
22
|
|
|
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
|
23
|
|
|
# |
|
24
|
|
|
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
|
25
|
|
|
# | Range Size | |
|
26
|
|
|
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
|
27
|
|
|
# // SID/Label Sub-TLV (variable) // |
|
28
|
|
|
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
|
29
|
|
|
# |
|
30
|
|
|
# SR Node Cap Flags |
|
31
|
|
|
# + |
|
32
|
|
|
# One or more entries, each of which have the following format: |
|
33
|
|
|
# |
|
34
|
|
|
# Range Size: 3 octet value indicating the number of labels in |
|
35
|
|
|
# the range. |
|
36
|
|
|
# |
|
37
|
|
|
# SID/Label sub-TLV (as defined in Section 2.3.7.2). |
|
38
|
|
|
|
|
39
|
|
|
|
|
40
|
|
|
@LINKSTATE.register() |
|
41
|
|
|
class SrCapabilities(object): |
|
42
|
|
|
TLV = 1034 |
|
43
|
|
|
|
|
44
|
|
|
def __init__(self, sr_flags, sids): |
|
45
|
|
|
self.sr_flags = sr_flags |
|
46
|
|
|
self.sids = sids |
|
47
|
|
|
|
|
48
|
|
|
def __repr__(self): |
|
49
|
|
|
return "sr_capability_flags: %s, sids: %s" % (self.sr_flags, self.sids) |
|
50
|
|
|
|
|
51
|
|
|
@classmethod |
|
52
|
|
|
def unpack(cls, data, length): |
|
53
|
|
|
# Extract node capability flags |
|
54
|
|
|
flags = LsGenericFlags.unpack(data[0:1], LsGenericFlags.ISIS_SR_CAP_FLAGS) |
|
55
|
|
|
# Move pointer past flags and reserved bytes |
|
56
|
|
|
data = data[2:] |
|
57
|
|
|
sids = [] |
|
58
|
|
|
while data: |
|
59
|
|
|
# Range Size: 3 octet value indicating the number of labels in |
|
60
|
|
|
# the range. |
|
61
|
|
|
range_size = unpack('!L', bytes([0]) + data[:3])[0] |
|
62
|
|
|
|
|
63
|
|
|
# SID/Label: If length is set to 3, then the 20 rightmost bits |
|
64
|
|
|
# represent a label. If length is set to 4, then the value |
|
65
|
|
|
# represents a 32 bit SID. |
|
66
|
|
|
t, l = unpack('!HH', data[3:7]) |
|
67
|
|
|
if t != 1161: |
|
68
|
|
|
raise Notify(3, 5, "Invalid sub-TLV type: {}".format(t)) |
|
69
|
|
|
v = data[7 : l + 7] |
|
70
|
|
|
if l == 3: |
|
71
|
|
|
sid = unpack('!L', bytes([0]) + data[:3])[0] |
|
72
|
|
|
elif l == 4: |
|
73
|
|
|
sid = unpack('!I', v)[0] |
|
74
|
|
|
sids.append((range_size, sid)) |
|
|
|
|
|
|
75
|
|
|
data = data[l + 7 :] |
|
76
|
|
|
|
|
77
|
|
|
return cls(sr_flags=flags, sids=sids) |
|
78
|
|
|
|
|
79
|
|
|
def json(self, compact=None): |
|
80
|
|
|
return ', '.join( |
|
81
|
|
|
['"sr-capability-flags": {}'.format(self.sr_flags.json()), '"sids": {}'.format(json.dumps(self.sids))] |
|
82
|
|
|
) |
|
83
|
|
|
|
Exa-Networks /
exabgp
Loading history...