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IgpMetric.unpack()   A

↳ Parent: exabgp.bgp.message.update.attribute.bgpls.link.igpmetric

Complexity

Conditions 4

Size

Total Lines 15
Code Lines 9

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
cc 4
eloc 9
nop 3
dl 0
loc 15
rs 9.95
c 0
b 0
f 0
1 
# encoding: utf-8
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"""
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igpmetric.py
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Created by Evelio Vila on 2016-12-01.

            


            
                                                                                                            
                            
            
                                    
            
            

                
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Copyright (c) 2014-2017 Exa Networks. All rights reserved.

            


            
                                                                                                            
                            
            
                                    
            
            

                
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"""

            


            
                                                                                                            
                            
            
                                    
            
            

                
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from struct import unpack

            


            
                                                                                                            
                            
            
                                    
            
            

                
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from exabgp.bgp.message.notification import Notify

            


            
                                                                                                            
                            
            
                                    
            
            

                
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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 BaseLS

            


            
                                                                                                            
                            
            
                                    
            
            

                
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#   The IGP Metric TLV carries the metric for this link.  The length of

            


            
                                                                                                            
                            
            
                                    
            
            

                
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#   this TLV is variable, depending on the metric width of the underlying

            


            
                                                                                                            
                            
            
                                    
            
            

                
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#   protocol.  IS-IS small metrics have a length of 1 octet (the two most

            


            
                                                                                                            
                            
            
                                    
            
            

                
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#   significant bits are ignored).  OSPF link metrics have a length of 2

            


            
                                                                                                            
                            
            
                                    
            
            

                
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#   octets.  IS-IS wide metrics have a length of 3 octets.

            


            
                                                                                                            
                            
            
                                    
            
            

                
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#

            


            
                                                                                                            
                            
            
                                    
            
            

                
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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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#     //      IGP Link Metric (variable length)      //

            


            
                                                                                                            
                            
            
                                    
            
            

                
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#     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

            


            
                                                                                                            
                            
            
                                    
            
            

                
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@LinkState.register()

            


            
                                                                                                            
                            
            
                                    
            
            

                
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class IgpMetric(BaseLS):

            


            
                                                                                                            
                            
            
                                    
            
            

                
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    TLV = 1095

            


            
                                                                                                            
                            
            
                                    
            
            

                
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    REPR = 'IGP Metric'

            


            
                                                                                                            
                            
            
                                    
            
            

                
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    JSON = 'igp-metric'

            


            
                                                                                                            
                                                                
            
                                    
            
            

                
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    @classmethod

            


            
                                                        
            
                                    
            
            

                
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    def unpack(cls, data, length):

            


            
                                                        
            
                                    
            
            

                
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        if len(data) == 2:

            


            
                                                        
            
                                    
            
            

                
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            # OSPF

            


            
                                                        
            
                                    
            
            

                
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            return cls(unpack('!H', data)[0])

            


            
                                                        
            
                                    
            
            

                
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        if len(data) == 1:

            


            
                                                        
            
                                    
            
            

                
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            # ISIS small metrics

            


            
                                                        
            
                                    
            
            

                
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            return cls(data[0])

            


            
                                                        
            
                                    
            
            

                
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        if len(data) == 3:

            


            
                                                        
            
                                    
            
            

                
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            # ISIS wide metrics

            


            
                                                        
            
                                    
            
            

                
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            return cls(unpack('!L', bytes([0]) + data)[0])

            


            
                                                        
            
                                    
            
            

                
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        raise Notify(3, 5, "Incorrect IGP Metric Size")

            


            
                                                        
            
                                    
            
            

                
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