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·657 lines (576 loc) · 24.4 KB
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"""
Mininet: A simple networking testbed for OpenFlow/SDN!
author: Bob Lantz (rlantz@cs.stanford.edu)
author: Brandon Heller (brandonh@stanford.edu)
Mininet creates scalable OpenFlow test networks by using
process-based virtualization and network namespaces.
Simulated hosts are created as processes in separate network
namespaces. This allows a complete OpenFlow network to be simulated on
top of a single Linux kernel.
Each host has:
A virtual console (pipes to a shell)
A virtual interfaces (half of a veth pair)
A parent shell (and possibly some child processes) in a namespace
Hosts have a network interface which is configured via ifconfig/ip
link/etc.
This version supports both the kernel and us
8000
er space datapaths
from the OpenFlow reference implementation (openflowswitch.org)
as well as OpenVSwitch (openvswitch.org.)
In kernel datapath mode, the controller and switches are simply
processes in the root namespace.
Kernel OpenFlow datapaths are instantiated using dpctl(8), and are
attached to the one side of a veth pair; the other side resides in the
host namespace. In this mode, switch processes can simply connect to the
controller via the loopback interface.
In user datapath mode, the controller and switches can be full-service
nodes that live in their own network namespaces and have management
interfaces and IP addresses on a control network (e.g. 192.168.123.1,
currently routed although it could be bridged.)
In addition to a management interface, user mode switches also have
several switch interfaces, halves of veth pairs whose other halves
reside in the host nodes that the switches are connected to.
Consistent, straightforward naming is important in order to easily
identify hosts, switches and controllers, both from the CLI and
from program code. Interfaces are named to make it easy to identify
which interfaces belong to which node.
The basic naming scheme is as follows:
Host nodes are named h1-hN
Switch nodes are named s1-sN
Controller nodes are named c0-cN
Interfaces are named {nodename}-eth0 .. {nodename}-ethN
Note: If the network topology is created using mininet.topo, then
node numbers are unique among hosts and switches (e.g. we have
h1..hN and SN..SN+M) and also correspond to their default IP addresses
of 10.x.y.z/8 where x.y.z is the base-256 representation of N for
hN. This mapping allows easy determination of a node's IP
address from its name, e.g. h1 -> 10.0.0.1, h257 -> 10.0.1.1.
Note also that 10.0.0.1 can often be written as 10.1 for short, e.g.
"ping 10.1" is equivalent to "ping 10.0.0.1".
Currently we wrap the entire network in a 'mininet' object, which
constructs a simulated network based on a network topology created
using a topology object (e.g. LinearTopo) from mininet.topo or
mininet.topolib, and a Controller which the switches will connect
to. Several configuration options are provided for functions such as
automatically setting MAC addresses, populating the ARP table, or
even running a set of terminals to allow direct interaction with nodes.
After the network is created, it can be started using start(), and a
variety of useful tasks maybe performed, including basic connectivity
and bandwidth tests and running the mininet CLI.
Once the network is up and running, test code can easily get access
to host and switch objects which can then be used for arbitrary
experiments, typically involving running a series of commands on the
hosts.
After all desired tests or activities have been completed, the stop()
method may be called to shut down the network.
"""
import os
import re
import select
import signal
from time import sleep
from datetime import datetime
from multiprocessing import Process
from mininet.cli import CLI
from mininet.log import info, error, debug, output
from mininet.node import Host, OVSKernelSwitch, Controller
from mininet.link import Link, Intf
from mininet.util import quietRun, fixLimits, numCores
from mininet.util import macColonHex, ipStr, ipParse, netParse, ipAdd
from mininet.term import cleanUpScreens, makeTerms
from mininet.monitor import Monitor
class Mininet( object ):
"Network emulation with hosts spawned in network namespaces."
def __init__( self, topo=None, switch=OVSKernelSwitch, host=Host,
controller=Controller, link=Link, intf=Intf,
build=True, xterms=False, cleanup=False, ipBase='10.0.0.0/8',
inNamespace=False,
autoSetMacs=False, autoStaticArp=False, autoPinCpus=False,
listenPort=None ):
"""Create Mininet object.
topo: Topo (topology) object or None
switch: default Switch class
host: default Host class/constructor
controller: default Controller class/constructor
link: default Link class/constructor
intf: default Intf class/constructor
ipBase: base IP address for hosts,
build: build now from topo?
xterms: if build now, spawn xterms?
cleanup: if build now, cleanup before creating?
inNamespace: spawn switches and controller in net namespaces?
autoSetMacs: set MAC addrs automatically like IP addresses?
autoStaticArp: set all-pairs static MAC addrs?
autoPinCpus: pin hosts to (real) cores (requires CPULimitedHost)?
listenPort: base listening port to open; will be incremented for
each additional switch in the net if inNamespace=False"""
self.topo = topo
self.switch = switch
self.host = host
self.controller = controller
self.link = link
self.intf = intf
self.ipBase = ipBase
self.ipBaseNum, self.prefixLen = netParse( self.ipBase )
self.nextIP = 1 # start for address allocation
self.inNamespace = inNamespace
self.xterms = xterms
self.cleanup = cleanup
self.autoSetMacs = autoSetMacs
self.autoStaticArp = autoStaticArp
self.autoPinCpus = autoPinCpus
self.numCores = numCores()
self.nextCore = 0 # next core for pinning hosts to CPUs
self.listenPort = listenPort
self.monitoring = None
self.hosts = []
self.switches = []
self.controllers = []
self.nameToNode = {} # name to Node (Host/Switch) objects
self.terms = [] # list of spawned xterm processes
Mininet.init() # Initialize Mininet if necessary
self.built = False
if topo and build:
self.build()
def set_debug(self, output_dir=None):
'''Enable debugging, with output to the specified directory'''
dt = datetime.now()
if not output_dir:
output_dir = '/tmp/mininet-%s-%s' % (str(dt.date()), str(dt.time()))
self.monitoring = Monitor(output_dir=output_dir)
def addHost( self, name, cls=None, **params ):
"""Add host.
name: name of host to add
cls: custom host class/constructor (optional)
params: parameters for host
returns: added host"""
# Default IP and MAC addresses
defaults = { 'ip': ipAdd( self.nextIP,
ipBaseNum=self.ipBaseNum,
prefixLen=self.prefixLen ) }
if self.autoSetMacs:
defaults[ 'mac'] = macColonHex( self.nextIP )
if self.autoPinCpus:
defaults[ 'cores' ] = self.nextCore
self.nextCore = ( self.nextCore + 1 ) % self.numCores
self.nextIP += 1
defaults.update( params )
if not cls:
cls = self.host
h = cls( name, **defaults )
self.hosts.append( h )
self.nameToNode[ name ] = h
return h
def addSwitch( self, name, cls=None, **params ):
"""Add switch.
name: name of switch to add
cls: custom switch class/constructor (optional)
returns: added switch
side effect: increments listenPort ivar ."""
defaults = { 'listenPort': self.listenPort,
'inNamespace': self.inNamespace }
defaults.update( params )
if not cls:
cls = self.switch
sw = cls( name, **defaults )
if not self.inNamespace and self.listenPort:
self.listenPort += 1
self.switches.append( sw )
self.nameToNode[ name ] = sw
return sw
def addController( self, name='c0', controller=None, **params ):
"""Add controller.
controller: Controller class"""
if not controller:
controller = self.controller
controller_new = controller( name, **params )
if controller_new: # allow controller-less setups
self.controllers.append( controller_new )
self.nameToNode[ name ] = controller_new
return controller_new
# BL: is this better than just using nameToNode[] ?
# Should it have a better name?
def getNodeByName( self, *args ):
"Return node(s) with given name(s)"
if len( args ) == 1:
return self.nameToNode[ args[ 0 ] ]
return [ self.nameToNode[ n ] for n in args ]
def addLink( self, node1, node2, port1=None, port2=None,
cls=None, **params ):
""""Add a link from node1 to node2
node1: source node
node2: dest node
port1: source port
port2: dest port
returns: link object"""
defaults = { 'port1': port1,
'port2': port2,
'intf': self.intf }
defaults.update( params )
if not cls:
cls = self.link
return cls( node1, node2, **defaults )
def configHosts( self ):
"Configure a set of hosts."
for host in self.hosts:
info( host.name + ' ' )
host.configDefault( defaultRoute=host.defaultIntf() )
# You're low priority, dude!
# BL: do we want to do this here or not?
# May not make sense if we have CPU lmiting...
# quietRun( 'renice +18 -p ' + repr( host.pid ) )
# This may not be the right place to do this, but
# it needs to be done somewhere.
host.cmd( 'ifconfig lo up' )
info( '\n' )
def buildFromTopo( self, topo=None ):
"""Build mininet from a topology object
At the end of this function, everything should be connected
and up."""
# Possibly we should clean up here and/or validate
# the topo
if self.cleanup:
pass
info( '*** Creating network\n' )
if not self.controllers:
# Add a default controller
info( '*** Adding controller\n' )
self.addController( 'c0' )
info( '*** Adding hosts:\n' )
for hostName in topo.hosts():
self.addHost( hostName, **topo.nodeInfo( hostName ) )
info( hostName + ' ' )
info( '\n*** Adding switches:\n' )
for switchName in topo.switches():
self.addSwitch( switchName, **topo.nodeInfo( switchName) )
info( switchName + ' ' )
info( '\n*** Adding links:\n' )
for srcName, dstName in topo.links(sort=True):
src, dst = self.nameToNode[ srcName ], self.nameToNode[ dstName ]
params = topo.linkInfo( srcName, dstName )
srcPort, dstPort = topo.port( srcName, dstName )
self.addLink( src, dst, srcPort, dstPort, **params )
info( '(%s, %s) ' % ( src.name, dst.name ) )
info( '\n' )
def configureControlNetwork( self ):
"Control net config hook: override in subclass"
raise Exception( 'configureControlNetwork: '
'should be overriden in subclass', self )
def build( self ):
"Build mininet."
if self.topo:
self.buildFromTopo( self.topo )
if ( self.inNamespace ):
self.configureControlNetwork()
info( '*** Configuring hosts\n' )
self.configHosts()
if self.xterms:
self.startTerms()
if self.autoStaticArp:
self.staticArp()
self.built = True
def startTerms( self ):
"Start a terminal for each node."
info( "*** Running terms on %s\n" % os.environ[ 'DISPLAY' ] )
cleanUpScreens()
self.terms += makeTerms( self.controllers, 'controller' )
self.terms += makeTerms( self.switches, 'switch' )
self.terms += makeTerms( self.hosts, 'host' )
def stopXterms( self ):
"Kill each xterm."
for term in self.terms:
os.kill( term.pid, signal.SIGKILL )
cleanUpScreens()
def staticArp( self ):
"Add all-pairs ARP entries to remove the need to handle broadcast."
for src in self.hosts:
for dst in self.hosts:
if src != dst:
src.setARP( ip=dst.IP(), mac=dst.MAC() )
def start( self ):
"Start controller and switches."
if not self.built:
self.build()
info( '*** Starting controller\n' )
for controller in self.controllers:
controller.start()
info( '*** Starting %s switches\n' % len( self.switches ) )
for switch in self.switches:
info( switch.name + ' ')
switch.start( self.controllers )
info( '\n' )
info( '*** Starting system monitor\n' )
if self.monitoring:
m = self.monitoring
m.monitors.append(Process(target=m.monitor_cpuacct,
args=(self.hosts, '%s/cpuacct.txt' % m.output_dir)))
m.start()
info( 'Logging monitoring info in: %s\n' % m.output_dir )
def stop( self ):
"Stop the controller(s), switches and hosts"
info( '*** Stopping system monitor\n' )
if self.monitoring:
self.monitoring.stop()
if self.terms:
info( '*** Stopping %i terms\n' % len( self.terms ) )
self.stopXterms()
info( '*** Stopping %i hosts\n' % len( self.hosts ) )
for host in self.hosts:
info( host.name + ' ' )
host.terminate()
info( '\n' )
info( '*** Stopping %i switches\n' % len( self.switches ) )
for switch in self.switches:
info( switch.name + ' ' )
switch.stop()
info( '\n' )
info( '*** Stopping %i controllers\n' % len( self.controllers ) )
for controller in self.controllers:
info( controller.name + ' ' )
controller.stop()
info( '\n' )
info( '\n*** Done\n' )
def run( self, test, *args, **kwargs ):
"Perform a complete start/test/stop cycle."
self.start()
info( '*** Running test\n' )
result = test( *args, **kwargs )
self.stop()
return result
def monitor( self, hosts=None, timeoutms=-1 ):
"""Monitor a set of hosts (or all hosts by default),
and return their output, a line at a time.
hosts: (optional) set of hosts to monitor
timeoutms: (optional) timeout value in ms
returns: iterator which returns host, line"""
if hosts is None:
hosts = self.hosts
poller = select.poll()
Node = hosts[ 0 ] # so we can call class method fdToNode
for host in hosts:
poller.register( host.stdout )
while True:
ready = poller.poll( timeoutms )
for fd, event in ready:
host = Node.fdToNode( fd )
if event & select.POLLIN:
line = host.readline()
if line is not None:
yield host, line
# Return if non-blocking
if not ready and timeoutms >= 0:
yield None, None
# XXX These test methods should be moved out of this class.
# Probably we should create a tests.py for them
@staticmethod
def _parsePing( pingOutput ):
"Parse ping output and return packets sent, received."
# Check for downed link
if 'connect: Network is unreachable' in pingOutput:
return (1, 0)
r = r'(\d+) packets transmitted, (\d+) received'
m = re.search( r, pingOutput )
if m == None:
error( '*** Error: could not parse ping output: %s\n' %
pingOutput )
return (1, 0)
sent, received = int( m.group( 1 ) ), int( m.group( 2 ) )
return sent, received
def ping( self, hosts=None ):
"""Ping between all specified hosts.
hosts: list of hosts
returns: ploss packet loss percentage"""
# should we check if running?
packets = 0
lost = 0
ploss = None
if not hosts:
hosts = self.hosts
output( '*** Ping: testing ping reachability\n' )
for node in hosts:
output( '%s -> ' % node.name )
for dest in hosts:
if node != dest:
result = node.cmd( 'ping -c1 ' + dest.IP() )
sent, received = self._parsePing( result )
packets += sent
if received > sent:
error( '*** Error: received too many packets' )
error( '%s' % result )
node.cmdPrint( 'route' )
exit( 1 )
lost += sent - received
output( ( '%s ' % dest.name ) if received else 'X ' )
output( '\n' )
ploss = 100 * lost / packets
output( "*** Results: %i%% dropped (%d/%d lost)\n" %
( ploss, lost, packets ) )
return ploss
def pingAll( self ):
"""Ping between all hosts.
returns: ploss packet loss percentage"""
return self.ping()
def pingPair( self ):
"""Ping between first two hosts, useful for testing.
returns: ploss packet loss percentage"""
hosts = [ self.hosts[ 0 ], self.hosts[ 1 ] ]
return self.ping( hosts=hosts )
@staticmethod
def _parseIperf( iperfOutput ):
"""Parse iperf output and return bandwidth.
iperfOutput: string
returns: result string"""
r = r'([\d\.]+ \w+/sec)'
m = re.findall( r, iperfOutput )
if m:
return m[-1]
else:
# was: raise Exception(...)
error( 'could not parse iperf output: ' + iperfOutput )
return ''
# XXX This should be cleaned up
def iperf( self, hosts=None, l4Type='TCP', udpBw='10M' ):
"""Run iperf between two hosts.
hosts: list of hosts; if None, uses opposite hosts
l4Type: string, one of [ TCP, UDP ]
returns: results two-element array of server and client speeds"""
if not quietRun( 'which telnet' ):
error( 'Cannot find telnet in $PATH - required for iperf test' )
return
if not hosts:
hosts = [ self.hosts[ 0 ], self.hosts[ -1 ] ]
else:
assert len( hosts ) == 2
client, server = hosts
output( '*** Iperf: testing ' + l4Type + ' bandwidth between ' )
output( "%s and %s\n" % ( client.name, server.name ) )
server.cmd( 'killall -9 iperf' )
iperfArgs = 'iperf '
bwArgs = ''
if l4Type == 'UDP':
iperfArgs += '-u '
bwArgs = '-b ' + udpBw + ' '
elif l4Type != 'TCP':
raise Exception( 'Unexpected l4 type: %s' % l4Type )
server.sendCmd( iperfArgs + '-s', printPid=True )
servout = ''
while server.lastPid is None:
servout += server.monitor()
if l4Type == 'TCP':
while 'Connected' not in client.cmd(
'sh -c "echo A | telnet -e A %s 5001"' % server.IP()):
output('waiting for iperf to start up...')
sleep(.5)
cliout = client.cmd( iperfArgs + '-t 5 -c ' + server.IP() + ' ' +
bwArgs )
debug( 'Client output: %s\n' % cliout )
server.sendInt()
servout += server.waitOutput()
debug( 'Server output: %s\n' % servout )
result = [ self._parseIperf( servout ), self._parseIperf( cliout ) ]
if l4Type == 'UDP':
result.insert( 0, udpBw )
output( '*** Results: %s\n' % result )
return result
# BL: I think this can be rewritten now that we have
# a real link class.
def configLinkStatus( self, src, dst, status ):
"""Change status of src <-> dst links.
src: node name
dst: node name
status: string {up, down}"""
if src not in self.nameToNode:
error( 'src not in network: %s\n' % src )
elif dst not in self.nameToNode:
error( 'dst not in network: %s\n' % dst )
else:
if type( src ) is str:
src = self.nameToNode[ src ]
if type( dst ) is str:
dst = self.nameToNode[ dst ]
connections = src.connectionsTo( dst )
if len( connections ) == 0:
error( 'src and dst not connected: %s %s\n' % ( src, dst) )
for srcIntf, dstIntf in connections:
result = srcIntf.ifconfig( status )
if result:
error( 'link src status change failed: %s\n' % result )
result = dstIntf.ifconfig( status )
if result:
error( 'link dst status change failed: %s\n' % result )
def interact( self ):
"Start network and run our simple CLI."
self.start()
result = CLI( self )
self.stop()
return result
inited = False
@classmethod
def init( cls ):
"Initialize Mininet"
if cls.inited:
return
if os.getuid() != 0:
# Note: this script must be run as root
# Probably we should only sudo when we need
# to as per Big Switch's patch
print "*** Mininet must run as root."
exit( 1 )
fixLimits()
cls.inited = True
class MininetWithControlNet( Mininet ):
"""Control network support:
Create an explicit control network. Currently this is only
used/usable with the user datapath.
Notes:
1. If the controller and switches are in the same (e.g. root)
namespace, they can just use the loopback connection.
2. If we can get unix domain sockets to work, we can use them
instead of an explicit control network.
3. Instead of routing, we could bridge or use 'in-band' control.
4. Even if we dispense with this in general, it could still be
useful for people who wish to simulate a separate control
network (since real networks may need one!)
5. Basically nobody ever used this code, so it has been moved
into its own class.
6. Ultimately we may wish to extend this to allow us to create a
control network which every node's control interface is
attached to."""
def configureControlNetwork( self ):
"Configure control network."
self.configureRoutedControlNetwork()
# We still need to figure out the right way to pass
# in the control network location.
def configureRoutedControlNetwork( self, ip='192.168.123.1',
prefixLen=16 ):
"""Configure a routed control network on controller and switches.
For use with the user datapath only right now."""
controller = self.controllers[ 0 ]
info( controller.name + ' <->' )
cip = ip
snum = ipParse( ip )
for switch in self.switches:
info( ' ' + switch.name )
link = self.link( switch, controller, port1=0 )
sintf, cintf = link.intf1, link.intf2
switch.controlIntf = sintf
snum += 1
while snum & 0xff in [ 0, 255 ]:
snum += 1
sip = ipStr( snum )
cintf.setIP( cip, prefixLen )
sintf.setIP( sip, prefixLen )
controller.setHostRoute( sip, cintf )
switch.setHostRoute( cip, sintf )
info( '\n' )
info( '*** Testing control network\n' )
while not cintf.isUp():
info( '*** Waiting for', cintf, 'to come up\n' )
sleep( 1 )
for switch in self.switches:
while not sintf.isUp():
info( '*** Waiting for', sintf, 'to come up\n' )
sleep( 1 )
if self.ping( hosts=[ switch, controller ] ) != 0:
error( '*** Error: control network test failed\n' )
exit( 1 )
info( '\n' )
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