#!/usr/bin/env python

'''@package topo

Network topology creation.

@author Brandon Heller ([email protected])

This package includes code to represent network topologies.

A Topo object can be a topology database for NOX, can represent a physical

setup for testing, and can even be emulated with the Mininet package.

'''

# BL: we may have to fix compatibility here.

# networkx is also a fairly heavyweight dependency

# from networkx.classes.graph import Graph

from networkx import Graph

from mininet.util import irange, natural, naturalSeq

class Topo(object):

"Data center network representation for structured multi-trees."

def __init__(self, hopts=None, sopts=None, lopts=None):

"""Topo object:

hinfo: default host options

sopts: default switch options

lopts: default link options"""

self.g = Graph()

self.node_info = {}

self.link_info = {} # (src, dst) tuples hash to EdgeInfo objects

self.hopts = {} if hopts is None else hopts

self.sopts = {} if sopts is None else sopts

self.lopts = {} if lopts is None else lopts

self.ports = {} # ports[src][dst] is port on src that connects to dst

def add_node(self, name, **opts):

"""Add Node to graph.

name: name

opts: node options

returns: node name"""

self.g.add_node(name)

self.node_info[name] = opts

return name

def add_host(self, name, **opts):

"""Convenience method: Add host to graph.

name: host name

opts: host options

returns: host name"""

if not opts and self.hopts:

opts = self.hopts

return self.add_node(name, **opts)

def add_switch(self, name, **opts):

"""Convenience method: Add switch to graph.

name: switch name

opts: switch options

returns: switch name"""

if not opts and self.sopts:

opts = self.sopts

result = self.add_node(name, is_switch=True, **opts)

return result

def add_link(self, node1, node2, port1=None, port2=None,

**opts):

"""node1, node2: nodes to link together

port1, port2: ports (optional)

opts: link options (optional)

returns: link info key"""

if not opts and self.lopts:

opts = self.lopts

self.add_port(node1, node2, port1, port2)

key = tuple(self.sorted([node1, node2]))

self.link_info[key] = opts

self.g.add_edge(*key)

return key

def add_port(self, src, dst, sport=None, dport=None):

'''Generate port mapping for new edge.

@param src source switch name

@param dst destination switch name

'''

self.ports.setdefault(src, {})

self.ports.setdefault(dst, {})

# New port: number of outlinks + base

src_base = 1 if self.is_switch(src) else 0

dst_base = 1 if self.is_switch(dst) else 0

if sport is None:

sport = len(self.ports[src]) + src_base

if dport is None:

dport = len(self.ports[dst]) + dst_base

self.ports[src][dst] = sport

self.ports[dst][src] = dport

def nodes(self, sort=True):

"Return nodes in graph"

if sort:

return self.sorted( self.g.nodes() )

else:

return self.g.nodes()

def is_switch(self, n):

'''Returns true if node is a switch.'''

info = self.node_info[n]

return info and info.get('is_switch', False)

def switches(self, sort=True):

'''Return switches.

sort: sort switches alphabetically

@return dpids list of dpids

'''

return [n for n in self.nodes(sort) if self.is_switch(n)]

def hosts(self, sort=True):

'''Return hosts.

sort: sort hosts alphabetically

@return dpids list of dpids

'''

return [n for n in self.nodes(sort) if not self.is_switch(n)]

def links(self, sort=True):

'''Return links.

sort: sort links alphabetically

@return links list of name pairs

'''

if not sort:

return self.g.edges()

else:

links = [tuple(self.sorted(e)) for e in self.g.edges()]

return sorted( links, key=naturalSeq )

def port(self, src, dst):

'''Get port number.

@param src source switch name

@param dst destination switch name

@return tuple (src_port, dst_port):

src_port: port on source switch leading to the destination switch

dst_port: port on destination switch leading to the source switch

'''

if src in self.ports and dst in self.ports[src]:

assert dst in self.ports and src in self.ports[dst]

return (self.ports[src][dst], self.ports[dst][src])

def linkInfo( self, src, dst ):

"Return link metadata"

src, dst = self.sorted([src, dst])

return self.link_info[(src, dst)]

def nodeInfo( self, name ):

"Return metadata (dict) for node"

info = self.node_info[ name ]

return info if info is not None else {}

def setNodeInfo( self, name, info ):

"Set metadata (dict) for node"

self.node_info[ name ] = info

@staticmethod

def sorted( items ):

"Items sorted in natural (i.e. alphabetical) order"

return sorted(items, key=natural)

class SingleSwitchTopo(Topo):

'''Single switch connected to k hosts.'''

def __init__(self, k=2, **opts):

'''Init.

@param k number of hosts

@param enable_all enables all nodes and switches?

'''

super(SingleSwitchTopo, self).__init__(**opts)

self.k = k

switch = self.add_switch('s1')

for h in irange(1, k):

host = self.add_host('h%s' % h)

self.add_link(host, switch)

class SingleSwitchReversedTopo(Topo):

'''Single switch connected to k hosts, with reversed ports.

The lowest-numbered host is connected to the highest-numbered port.

Useful to verify that Mininet properly handles custom port numberings.

'''

def __init__(self, k=2, **opts):

'''Init.

@param k number of hosts

@param enable_all enables all nodes and switches?

'''

super(SingleSwitchReversedTopo, self).__init__(**opts)

self.k = k

switch = self.add_switch('s1')

for h in irange(1, k):

host = self.add_host('h%s' % h)

self.add_link(host, switch,

port1=0, port2=(k - h + 1))

class LinearTopo(Topo):

"Linear topology of k switches, with one host per switch."

def __init__(self, k=2, **opts):

"""Init.

k: number of switches (and hosts)

hconf: host configuration options

lconf: link configuration options"""

super(LinearTopo, self).__init__(**opts)

self.k = k

lastSwitch = None

for i in irange(1, k):

host = self.add_host('h%s' % i)

switch = self.add_switch('s%s' % i)

self.add_link( host, switch)

if lastSwitch:

self.add_link( switch, lastSwitch)

lastSwitch = switch