Bob Lantz
6cb68f26c9
The justification for this is that 1) the options are already documented in the API documentation and 2) the class names are fairly self-explanatory, so adding short descriptions doesn't add much. In the future, however, we could add a short description by simply using the first line or sentence of the docstring; note that docstrings would have to be canonicalized, which they aren't now.
355 lines
12 KiB
Python
355 lines
12 KiB
Python
#!/usr/bin/env python
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"""@package topo
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Network topology creation.
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@author Brandon Heller (brandonh@stanford.edu)
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This package includes code to represent network topologies.
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A Topo object can be a topology database for NOX, can represent a physical
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setup for testing, and can even be emulated with the Mininet package.
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"""
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from mininet.util import irange, natural, naturalSeq
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class MultiGraph( object ):
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"Utility class to track nodes and edges - replaces networkx.MultiGraph"
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def __init__( self ):
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self.node = {}
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self.edge = {}
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def add_node( self, node, attr_dict=None, **attrs):
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"""Add node to graph
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attr_dict: attribute dict (optional)
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attrs: more attributes (optional)
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warning: updates attr_dict with attrs"""
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attr_dict = {} if attr_dict is None else attr_dict
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attr_dict.update( attrs )
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self.node[ node ] = attr_dict
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def add_edge( self, src, dst, key=None, attr_dict=None, **attrs ):
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"""Add edge to graph
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key: optional key
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attr_dict: optional attribute dict
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attrs: more attributes
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warning: udpates attr_dict with attrs"""
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attr_dict = {} if attr_dict is None else attr_dict
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attr_dict.update( attrs )
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self.node.setdefault( src, {} )
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self.node.setdefault( dst, {} )
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self.edge.setdefault( src, {} )
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self.edge.setdefault( dst, {} )
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self.edge[ src ].setdefault( dst, {} )
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entry = self.edge[ dst ][ src ] = self.edge[ src ][ dst ]
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# If no key, pick next ordinal number
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if key is None:
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keys = [ k for k in entry.keys() if isinstance( k, int ) ]
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key = max( [ 0 ] + keys ) + 1
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entry[ key ] = attr_dict
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return key
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def nodes( self, data=False):
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"""Return list of graph nodes
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data: return list of ( node, attrs)"""
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return self.node.items() if data else self.node.keys()
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def edges_iter( self, data=False, keys=False ):
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"Iterator: return graph edges"
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for src, entry in self.edge.iteritems():
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for dst, keys in entry.iteritems():
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if src > dst:
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# Skip duplicate edges
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continue
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for k, attrs in keys.iteritems():
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if data:
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if keys:
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yield( src, dst, k, attrs )
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else:
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yield( src, dst, attrs )
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else:
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if keys:
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yield( src, dst, k )
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else:
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yield( src, dst )
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def edges( self, data=False, keys=False ):
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"Return list of graph edges"
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return list( self.edges_iter( data=data, keys=keys ) )
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def __getitem__( self, node ):
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"Return link dict for given src node"
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return self.edge[ node ]
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def __len__( self ):
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"Return the number of nodes"
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return len( self.node )
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def convertTo( self, cls, data=False, keys=False ):
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"""Convert to a new object of networkx.MultiGraph-like class cls
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data: include node and edge data
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keys: include edge keys as well as edge data"""
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g = cls()
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g.add_nodes_from( self.nodes( data=data ) )
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g.add_edges_from( self.edges( data=( data or keys ), keys=keys ) )
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return g
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class Topo( object ):
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"Data center network representation for structured multi-trees."
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def __init__( self, *args, **params ):
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"""Topo object.
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Optional named parameters:
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hinfo: default host options
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sopts: default switch options
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lopts: default link options
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calls build()"""
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self.g = MultiGraph()
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self.hopts = params.pop( 'hopts', {} )
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self.sopts = params.pop( 'sopts', {} )
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self.lopts = params.pop( 'lopts', {} )
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# ports[src][dst][sport] is port on dst that connects to src
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self.ports = {}
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self.build( *args, **params )
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def build( self, *args, **params ):
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"Override this method to build your topology."
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pass
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def addNode( self, name, **opts ):
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"""Add Node to graph.
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name: name
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opts: node options
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returns: node name"""
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self.g.add_node( name, **opts )
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return name
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def addHost( self, name, **opts ):
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"""Convenience method: Add host to graph.
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name: host name
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opts: host options
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returns: host name"""
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if not opts and self.hopts:
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opts = self.hopts
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return self.addNode( name, **opts )
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def addSwitch( self, name, **opts ):
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"""Convenience method: Add switch to graph.
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name: switch name
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opts: switch options
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returns: switch name"""
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if not opts and self.sopts:
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opts = self.sopts
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result = self.addNode( name, isSwitch=True, **opts )
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return result
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def addLink( self, node1, node2, port1=None, port2=None,
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key=None, **opts ):
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"""node1, node2: nodes to link together
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port1, port2: ports (optional)
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opts: link options (optional)
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returns: link info key"""
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if not opts and self.lopts:
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opts = self.lopts
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port1, port2 = self.addPort( node1, node2, port1, port2 )
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opts = dict( opts )
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opts.update( node1=node1, node2=node2, port1=port1, port2=port2 )
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self.g.add_edge(node1, node2, key, opts )
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return key
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def nodes( self, sort=True ):
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"Return nodes in graph"
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if sort:
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return self.sorted( self.g.nodes() )
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else:
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return self.g.nodes()
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def isSwitch( self, n ):
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"Returns true if node is a switch."
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return self.g.node[ n ].get( 'isSwitch', False )
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def switches( self, sort=True ):
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"""Return switches.
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sort: sort switches alphabetically
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returns: dpids list of dpids"""
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return [ n for n in self.nodes( sort ) if self.isSwitch( n ) ]
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def hosts( self, sort=True ):
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"""Return hosts.
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sort: sort hosts alphabetically
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returns: list of hosts"""
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return [ n for n in self.nodes( sort ) if not self.isSwitch( n ) ]
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def iterLinks( self, withKeys=False, withInfo=False ):
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"""Return links (iterator)
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withKeys: return link keys
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withInfo: return link info
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returns: list of ( src, dst [,key, info ] )"""
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for _src, _dst, key, info in self.g.edges_iter( data=True, keys=True ):
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node1, node2 = info[ 'node1' ], info[ 'node2' ]
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if withKeys:
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if withInfo:
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yield( node1, node2, key, info )
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else:
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yield( node1, node2, key )
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else:
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if withInfo:
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yield( node1, node2, info )
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else:
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yield( node1, node2 )
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def links( self, sort=False, withKeys=False, withInfo=False ):
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"""Return links
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sort: sort links alphabetically, preserving (src, dst) order
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withKeys: return link keys
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withInfo: return link info
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returns: list of ( src, dst [,key, info ] )"""
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links = list( self.iterLinks( withKeys, withInfo ) )
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if not sort:
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return links
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# Ignore info when sorting
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tupleSize = 3 if withKeys else 2
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return sorted( links, key=( lambda l: naturalSeq( l[ :tupleSize ] ) ) )
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# This legacy port management mechanism is clunky and will probably
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# be removed at some point.
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def addPort( self, src, dst, sport=None, dport=None ):
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"""Generate port mapping for new edge.
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src: source switch name
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dst: destination switch name"""
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# Initialize if necessary
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ports = self.ports
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ports.setdefault( src, {} )
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ports.setdefault( dst, {} )
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# New port: number of outlinks + base
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if sport is None:
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src_base = 1 if self.isSwitch( src ) else 0
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sport = len( ports[ src ] ) + src_base
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if dport is None:
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dst_base = 1 if self.isSwitch( dst ) else 0
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dport = len( ports[ dst ] ) + dst_base
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ports[ src ][ sport ] = ( dst, dport )
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ports[ dst ][ dport ] = ( src, sport )
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return sport, dport
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def port( self, src, dst ):
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"""Get port numbers.
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src: source switch name
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dst: destination switch name
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sport: optional source port (otherwise use lowest src port)
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returns: tuple (sport, dport), where
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sport = port on source switch leading to the destination switch
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dport = port on destination switch leading to the source switch
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Note that you can also look up ports using linkInfo()"""
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# A bit ugly and slow vs. single-link implementation ;-(
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ports = [ ( sport, entry[ 1 ] )
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for sport, entry in self.ports[ src ].items()
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if entry[ 0 ] == dst ]
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return ports if len( ports ) != 1 else ports[ 0 ]
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def _linkEntry( self, src, dst, key=None ):
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"Helper function: return link entry and key"
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entry = self.g[ src ][ dst ]
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if key is None:
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key = min( entry )
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return entry, key
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def linkInfo( self, src, dst, key=None ):
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"Return link metadata dict"
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entry, key = self._linkEntry( src, dst, key )
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return entry[ key ]
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def setlinkInfo( self, src, dst, info, key=None ):
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"Set link metadata dict"
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entry, key = self._linkEntry( src, dst, key )
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entry[ key ] = info
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def nodeInfo( self, name ):
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"Return metadata (dict) for node"
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return self.g.node[ name ]
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def setNodeInfo( self, name, info ):
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"Set metadata (dict) for node"
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self.g.node[ name ] = info
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def convertTo( self, cls, data=True, keys=True ):
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"""Convert to a new object of networkx.MultiGraph-like class cls
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data: include node and edge data (default True)
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keys: include edge keys as well as edge data (default True)"""
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return self.g.convertTo( cls, data=data, keys=keys )
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@staticmethod
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def sorted( items ):
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"Items sorted in natural (i.e. alphabetical) order"
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return sorted( items, key=natural )
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# Our idiom defines additional parameters in build(param...)
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# pylint: disable=arguments-differ
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class SingleSwitchTopo( Topo ):
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"Single switch connected to k hosts."
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def build( self, k=2, **_opts ):
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"k: number of hosts"
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self.k = k
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switch = self.addSwitch( 's1' )
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for h in irange( 1, k ):
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host = self.addHost( 'h%s' % h )
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self.addLink( host, switch )
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class SingleSwitchReversedTopo( Topo ):
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"""Single switch connected to k hosts, with reversed ports.
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The lowest-numbered host is connected to the highest-numbered port.
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Useful to verify that Mininet properly handles custom port
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numberings."""
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def build( self, k=2 ):
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"k: number of hosts"
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self.k = k
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switch = self.addSwitch( 's1' )
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for h in irange( 1, k ):
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host = self.addHost( 'h%s' % h )
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self.addLink( host, switch,
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port1=0, port2=( k - h + 1 ) )
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class MinimalTopo( SingleSwitchTopo ):
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"Minimal topology with two hosts and one switch"
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def build( self ):
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return SingleSwitchTopo.build( self, k=2 )
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class LinearTopo( Topo ):
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"Linear topology of k switches, with n hosts per switch."
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def build( self, k=2, n=1, **_opts):
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"""k: number of switches
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n: number of hosts per switch"""
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self.k = k
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self.n = n
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if n == 1:
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genHostName = lambda i, j: 'h%s' % i
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else:
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genHostName = lambda i, j: 'h%ss%d' % ( j, i )
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lastSwitch = None
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for i in irange( 1, k ):
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# Add switch
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switch = self.addSwitch( 's%s' % i )
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# Add hosts to switch
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for j in irange( 1, n ):
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host = self.addHost( genHostName( i, j ) )
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self.addLink( host, switch )
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# Connect switch to previous
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if lastSwitch:
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self.addLink( switch, lastSwitch )
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lastSwitch = switch
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# pylint: enable=arguments-differ
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