"""

Node objects for Mininet.

Nodes provide a simple abstraction for interacting with hosts, switches

and controllers. Local nodes are simply one or more processes on the local

machine.

Node: superclass for all (primarily local) network nodes.

Host: a virtual host. By default, a host is simply a shell; commands

may be sent using Cmd (which waits for output), or using sendCmd(),

which returns immediately, allowing subsequent monitoring using

monitor(). Examples of how to run experiments using this

functionality are provided in the examples/ directory. By default,

hosts share the root file system, but they may also specify private

directories.

CPULimitedHost: a virtual host whose CPU bandwidth is limited by

RT or CFS bandwidth limiting.

Switch: superclass for switch nodes.

UserSwitch: a switch using the user-space switch from the OpenFlow

reference implementation.

KernelSwitch: a switch using the kernel switch from the OpenFlow reference

implementation.

OVSSwitch: a switch using the OpenVSwitch OpenFlow-compatible switch

implementation (openvswitch.org).

Controller: superclass for OpenFlow controllers. The default controller

is controller(8) from the reference implementation.

NOXController: a controller node using NOX (noxrepo.org).

RemoteController: a remote controller node, which may use any

arbitrary OpenFlow-compatible controller, and which is not

created or managed by mininet.

Future enhancements:

- Possibly make Node, Switch and Controller more abstract so that

they can be used for both local and remote nodes

- Create proxy objects for remote nodes (Mininet: Cluster Edition)

"""

import os

import pty

import re

import signal

import select

from subprocess import Popen, PIPE

from time import sleep

from mininet.log import info, error, warn, debug

from mininet.util import ( quietRun, errRun, errFail, moveIntf, isShellBuiltin,

numCores, retry, mountCgroups )

from mininet.moduledeps import moduleDeps, pathCheck, OVS_KMOD, OF_KMOD, TUN

from mininet.link import Link, Intf, TCIntf, OVSIntf

from re import findall

from distutils.version import StrictVersion

class Node( object ):

"""A virtual network node is simply a shell in a network namespace.

We communicate with it using pipes."""

portBase = 0 # Nodes always start with eth0/port0, even in OF 1.0

def __init__( self, name, inNamespace=True, **params ):

"""name: name of node

inNamespace: in network namespace?

privateDirs: list of private directory strings or tuples

params: Node parameters (see config() for details)"""

# Make sure class actually works

self.checkSetup()

self.name = params.get( 'name', name )

self.privateDirs = params.get( 'privateDirs', [] )

self.inNamespace = params.get( 'inNamespace', inNamespace )

# Stash configuration parameters for future reference

self.params = params

self.intfs = {} # dict of port numbers to interfaces

self.ports = {} # dict of interfaces to port numbers

# replace with Port objects, eventually ?

self.nameToIntf = {} # dict of interface names to Intfs

# Make pylint happy

( self.shell, self.execed, self.pid, self.stdin, self.stdout,

self.lastPid, self.lastCmd, self.pollOut ) = (

None, None, None, None, None, None, None, None )

self.waiting = False

self.readbuf = ''

# Start command interpreter shell

self.startShell()

self.mountPrivateDirs()

# File descriptor to node mapping support

# Class variables and methods

inToNode = {} # mapping of input fds to nodes

outToNode = {} # mapping of output fds to nodes

@classmethod

def fdToNode( cls, fd ):

"""Return node corresponding to given file descriptor.

fd: file descriptor

returns: node"""

node = cls.outToNode.get( fd )

return node or cls.inToNode.get( fd )

# Command support via shell process in namespace

def startShell( self, mnopts=None ):

"Start a shell process for running commands"

if self.shell:

error( "%s: shell is already running\n" % self.name )

return

# mnexec: (c)lose descriptors, (d)etach from tty,

# (p)rint pid, and run in (n)amespace

opts = '-cd' if mnopts is None else mnopts

if self.inNamespace:

opts += 'n'

# bash -m: enable job control, i: force interactive

# -s: pass $* to shell, and make process easy to find in ps

# prompt is set to sentinel chr( 127 )

cmd = [ 'mnexec', opts, 'env', 'PS1=' + chr( 127 ),

'bash', '--norc', '-mis', 'mininet:' + self.name ]

# Spawn a shell subprocess in a pseudo-tty, to disable buffering

# in the subprocess and insulate it from signals (e.g. SIGINT)

# received by the parent

master, slave = pty.openpty()

self.shell = self._popen( cmd, stdin=slave, stdout=slave, stderr=slave,

close_fds=False )

self.stdin = os.fdopen( master, 'rw' )

self.stdout = self.stdin

self.pid = self.shell.pid

self.pollOut = select.poll()

self.pollOut.register( self.stdout )

# Maintain mapping between file descriptors and nodes

# This is useful for monitoring multiple nodes

# using select.poll()

self.outToNode[ self.stdout.fileno() ] = self

self.inToNode[ self.stdin.fileno() ] = self

self.execed = False

self.lastCmd = None

self.lastPid = None

self.readbuf = ''

# Wait for prompt

while True:

data = self.read( 1024 )

if data[ -1 ] == chr( 127 ):

break

self.pollOut.poll()

self.waiting = False

self.cmd( 'stty -echo' )

self.cmd( 'set +m' )

def mountPrivateDirs( self ):

"mount private directories"

for directory in self.privateDirs:

if isinstance( directory, tuple ):

# mount given private directory

privateDir = directory[ 1 ] % self.__dict__

mountPoint = directory[ 0 ]

self.cmd( 'mkdir -p %s' % privateDir )

self.cmd( 'mkdir -p %s' % mountPoint )

self.cmd( 'mount --bind %s %s' %

( privateDir, mountPoint ) )

else:

# mount temporary filesystem on directory

self.cmd( 'mkdir -p %s' % directory )

self.cmd( 'mount -n -t tmpfs tmpfs %s' % directory )

def unmountPrivateDirs( self ):

"mount private directories"

for directory in self.privateDirs:

if isinstance( directory, tuple ):

self.cmd( 'umount ', directory[ 0 ] )

else:

self.cmd( 'umount ', directory )

def _popen( self, cmd, **params ):

"""Internal method: spawn and return a process

cmd: command to run (list)

params: parameters to Popen()"""

# Leave this is as an instance method for now

assert self

return Popen( cmd, **params )

def cleanup( self ):

"Help python collect its garbage."

# Intfs may end up in root NS

for intfName in self.intfNames():

if self.name in intfName:

quietRun( 'ip link del ' + intfName )

self.shell = None

# Subshell I/O, commands and control

def read( self, maxbytes=1024 ):

"""Buffered read from node, non-blocking.

maxbytes: maximum number of bytes to return"""

count = len( self.readbuf )

if count < maxbytes:

data = os.read( self.stdout.fileno(), maxbytes - count )

self.readbuf += data

if maxbytes >= len( self.readbuf ):

result = self.readbuf

self.readbuf = ''

else:

result = self.readbuf[ :maxbytes ]

self.readbuf = self.readbuf[ maxbytes: ]

return result

def readline( self ):

"""Buffered readline from node, non-blocking.

returns: line (minus newline) or None"""

self.readbuf += self.read( 1024 )

if '\n' not in self.readbuf:

return None

pos = self.readbuf.find( '\n' )

line = self.readbuf[ 0: pos ]

self.readbuf = self.readbuf[ pos + 1: ]

return line

def write( self, data ):

"""Write data to node.

data: string"""

os.write( self.stdin.fileno(), data )

def terminate( self ):

"Send kill signal to Node and clean up after it."

self.unmountPrivateDirs()

if self.shell:

if self.shell.poll() is None:

os.killpg( self.shell.pid, signal.SIGHUP )

self.cleanup()

def stop( self, deleteIntfs=False ):

"""Stop node.

deleteIntfs: delete interfaces? (False)"""

if deleteIntfs:

self.deleteIntfs()

self.terminate()

def waitReadable( self, timeoutms=None ):

"""Wait until node's output is readable.

timeoutms: timeout in ms or None to wait indefinitely."""

if len( self.readbuf ) == 0:

self.pollOut.poll( timeoutms )

def sendCmd( self, *args, **kwargs ):

"""Send a command, followed by a command to echo a sentinel,

and return without waiting for the command to complete.

args: command and arguments, or string

printPid: print command's PID?"""

assert not self.waiting

printPid = kwargs.get( 'printPid', True )

# Allow sendCmd( [ list ] )

if len( args ) == 1 and isinstance( args[ 0 ], list ):

cmd = args[ 0 ]

# Allow sendCmd( cmd, arg1, arg2... )

elif len( args ) > 0:

cmd = args

# Convert to string

if not isinstance( cmd, str ):

cmd = ' '.join( [ str( c ) for c in cmd ] )

if not re.search( r'\w', cmd ):

# Replace empty commands with something harmless

cmd = 'echo -n'

self.lastCmd = cmd

# if a builtin command is backgrounded, it still yields a PID

if len( cmd ) > 0 and cmd[ -1 ] == '&':

# print ^A{pid}\n so monitor() can set lastPid

cmd += ' printf "\\001%d\\012" $! '

elif printPid and not isShellBuiltin( cmd ):

cmd = 'mnexec -p ' + cmd

self.write( cmd + '\n' )

self.lastPid = None

self.waiting = True

def sendInt( self, intr=chr( 3 ) ):

"Interrupt running command."

debug( 'sendInt: writing chr(%d)\n' % ord( intr ) )

self.write( intr )

def monitor( self, timeoutms=None, findPid=True ):

"""Monitor and return the output of a command.

Set self.waiting to False if command has completed.

timeoutms: timeout in ms or None to wait indefinitely

findPid: look for PID from mnexec -p"""

self.waitReadable( timeoutms )

data = self.read( 1024 )

pidre = r'\[\d+\] \d+\r\n'

# Look for PID

marker = chr( 1 ) + r'\d+\r\n'

if findPid and chr( 1 ) in data:

# suppress the job and PID of a backgrounded command

if re.findall( pidre, data ):

data = re.sub( pidre, '', data )

# Marker can be read in chunks; continue until all of it is read

while not re.findall( marker, data ):

data += self.read( 1024 )

markers = re.findall( marker, data )

if markers:

self.lastPid = int( markers[ 0 ][ 1: ] )

data = re.sub( marker, '', data )

# Look for sentinel/EOF

if len( data ) > 0 and data[ -1 ] == chr( 127 ):

self.waiting = False

data = data[ :-1 ]

elif chr( 127 ) in data:

self.waiting = False

data = data.replace( chr( 127 ), '' )

return data

def waitOutput( self, verbose=False, findPid=True ):

"""Wait for a command to complete.

Completion is signaled by a sentinel character, ASCII(127)

appearing in the output stream. Wait for the sentinel and return

the output, including trailing newline.

verbose: print output interactively"""

log = info if verbose else debug

output = ''

while self.waiting:

data = self.monitor( findPid=findPid )

output += data

log( data )

return output

def cmd( self, *args, **kwargs ):

"""Send a command, wait for output, and return it.

cmd: string"""

verbose = kwargs.get( 'verbose', False )

log = info if verbose else debug

log( '*** %s : %s\n' % ( self.name, args ) )

self.sendCmd( *args, **kwargs )

return self.waitOutput( verbose )

def cmdPrint( self, *args):

"""Call cmd and printing its output

cmd: string"""

return self.cmd( *args, **{ 'verbose': True } )

def popen( self, *args, **kwargs ):

"""Return a Popen() object in our namespace

args: Popen() args, single list, or string

kwargs: Popen() keyword args"""

defaults = { 'stdout': PIPE, 'stderr': PIPE,

'mncmd':

[ 'mnexec', '-da', str( self.pid ) ] }

defaults.update( kwargs )

if len( args ) == 1:

if isinstance( args[ 0 ], list ):

# popen([cmd, arg1, arg2...])

cmd = args[ 0 ]

elif isinstance( args[ 0 ], basestring ):

# popen("cmd arg1 arg2...")

cmd = args[ 0 ].split()

else:

raise Exception( 'popen() requires a string or list' )

elif len( args ) > 0:

# popen( cmd, arg1, arg2... )

cmd = list( args )

# Attach to our namespace using mnexec -a

cmd = defaults.pop( 'mncmd' ) + cmd

# Shell requires a string, not a list!

if defaults.get( 'shell', False ):

cmd = ' '.join( cmd )

popen = self._popen( cmd, **defaults )

return popen

def pexec( self, *args, **kwargs ):

"""Execute a command using popen

returns: out, err, exitcode"""

popen = self.popen( *args, stdin=PIPE, stdout=PIPE, stderr=PIPE,

**kwargs )

# Warning: this can fail with large numbers of fds!

out, err = popen.communicate()

exitcode = popen.wait()

return out, err, exitcode

# Interface management, configuration, and routing

# BL notes: This might be a bit redundant or over-complicated.

# However, it does allow a bit of specialization, including

# changing the canonical interface names. It's also tricky since

# the real interfaces are created as veth pairs, so we can't

# make a single interface at a time.

def newPort( self ):

"Return the next port number to allocate."

if len( self.ports ) > 0:

return max( self.ports.values() ) + 1

return self.portBase

def addIntf( self, intf, port=None, moveIntfFn=moveIntf ):

"""Add an interface.

intf: interface

port: port number (optional, typically OpenFlow port number)

moveIntfFn: function to move interface (optional)"""

if port is None:

port = self.newPort()

self.intfs[ port ] = intf

self.ports[ intf ] = port

self.nameToIntf[ intf.name ] = intf

debug( '\n' )

debug( 'added intf %s (%d) to node %s\n' % (

intf, port, self.name ) )

if self.inNamespace:

debug( 'moving', intf, 'into namespace for', self.name, '\n' )

moveIntfFn( intf.name, self )

def defaultIntf( self ):

"Return interface for lowest port"

ports = self.intfs.keys()

if ports:

return self.intfs[ min( ports ) ]

else:

warn( '*** defaultIntf: warning:', self.name,

'has no interfaces\n' )

def intf( self, intf=None ):

"""Return our interface object with given string name,

default intf if name is falsy (None, empty string, etc).

or the input intf arg.

Having this fcn return its arg for Intf objects makes it

easier to construct functions with flexible input args for

interfaces (those that accept both string names and Intf objects).

"""

if not intf:

return self.defaultIntf()

elif isinstance( intf, basestring):

return self.nameToIntf[ intf ]

else:

return intf

def connectionsTo( self, node):

"Return [ intf1, intf2... ] for all intfs that connect self to node."

# We could optimize this if it is important

connections = []

for intf in self.intfList():

link = intf.link

if link:

node1, node2 = link.intf1.node, link.intf2.node

if node1 == self and node2 == node:

connections += [ ( intf, link.intf2 ) ]

elif node1 == node and node2 == self:

connections += [ ( intf, link.intf1 ) ]

return connections

def deleteIntfs( self, checkName=True ):

"""Delete all of our interfaces.

checkName: only delete interfaces that contain our name"""

# In theory the interfaces should go away after we shut down.

# However, this takes time, so we're better off removing them

# explicitly so that we won't get errors if we run before they

# have been removed by the kernel. Unfortunately this is very slow,

# at least with Linux kernels before 2.6.33

for intf in self.intfs.values():

# Protect against deleting hardware interfaces

if ( self.name in intf.name ) or ( not checkName ):

intf.delete()

info( '.' )

# Routing support

def setARP( self, ip, mac ):

"""Add an ARP entry.

ip: IP address as string

mac: MAC address as string"""

result = self.cmd( 'arp', '-s', ip, mac )

return result

def setHostRoute( self, ip, intf ):

"""Add route to host.

ip: IP address as dotted decimal

intf: string, interface name"""

return self.cmd( 'route add -host', ip, 'dev', intf )

def setDefaultRoute( self, intf=None ):

"""Set the default route to go through intf.

intf: Intf or {dev <intfname> via <gw-ip> ...}"""

# Note setParam won't call us if intf is none

if isinstance( intf, basestring ) and ' ' in intf:

params = intf

else:

params = 'dev %s' % intf

# Do this in one line in case we're messing with the root namespace

self.cmd( 'ip route del default; ip route add default', params )

# Convenience and configuration methods

def setMAC( self, mac, intf=None ):

"""Set the MAC address for an interface.

intf: intf or intf name

mac: MAC address as string"""

return self.intf( intf ).setMAC( mac )

def setIP( self, ip, prefixLen=8, intf=None ):

"""Set the IP address for an interface.

intf: intf or intf name

ip: IP address as a string

prefixLen: prefix length, e.g. 8 for /8 or 16M addrs"""

# This should probably be rethought

if '/' not in ip:

ip = '%s/%s' % ( ip, prefixLen )

return self.intf( intf ).setIP( ip )

def IP( self, intf=None ):

"Return IP address of a node or specific interface."

return self.intf( intf ).IP()

def MAC( self, intf=None ):

"Return MAC address of a node or specific interface."

return self.intf( intf ).MAC()

def intfIsUp( self, intf=None ):

"Check if an interface is up."

return self.intf( intf ).isUp()

# The reason why we configure things in this way is so

# That the parameters can be listed and documented in

# the config method.

# Dealing with subclasses and superclasses is slightly

# annoying, but at least the information is there!

def setParam( self, results, method, **param ):

"""Internal method: configure a *single* parameter

results: dict of results to update

method: config method name

param: arg=value (ignore if value=None)

value may also be list or dict"""

name, value = param.items()[ 0 ]

if value is None:

return

f = getattr( self, method, None )

if not f:

return

if isinstance( value, list ):

result = f( *value )

elif isinstance( value, dict ):

result = f( **value )

else:

result = f( value )

results[ name ] = result

return result

def config( self, mac=None, ip=None,

defaultRoute=None, lo='up', **_params ):

"""Configure Node according to (optional) parameters:

mac: MAC address for default interface

ip: IP address for default interface

ifconfig: arbitrary interface configuration

Subclasses should override this method and call

the parent class's config(**params)"""

# If we were overriding this method, we would call

# the superclass config method here as follows:

# r = Parent.config( **_params )

r = {}

self.setParam( r, 'setMAC', mac=mac )

self.setParam( r, 'setIP', ip=ip )

self.setParam( r, 'setDefaultRoute', defaultRoute=defaultRoute )

# This should be examined

self.cmd( 'ifconfig lo ' + lo )

return r

def configDefault( self, **moreParams ):

"Configure with default parameters"

self.params.update( moreParams )

self.config( **self.params )

# This is here for backward compatibility

def linkTo( self, node, link=Link ):

"""(Deprecated) Link to another node

replace with Link( node1, node2)"""

return link( self, node )

# Other methods

def intfList( self ):

"List of our interfaces sorted by port number"

return [ self.intfs[ p ] for p in sorted( self.intfs.iterkeys() ) ]

def intfNames( self ):

"The names of our interfaces sorted by port number"

return [ str( i ) for i in self.intfList() ]

def __repr__( self ):

"More informative string representation"

intfs = ( ','.join( [ '%s:%s' % ( i.name, i.IP() )

for i in self.intfList() ] ) )

return '<%s %s: %s pid=%s> ' % (

self.__class__.__name__, self.name, intfs, self.pid )

def __str__( self ):

"Abbreviated string representation"

return self.name

# Automatic class setup support

isSetup = False

@classmethod

def checkSetup( cls ):

"Make sure our class and superclasses are set up"

while cls and not getattr( cls, 'isSetup', True ):

cls.setup()

cls.isSetup = True

# Make pylint happy

cls = getattr( type( cls ), '__base__', None )

@classmethod

def setup( cls ):

"Make sure our class dependencies are available"

pathCheck( 'mnexec', 'ifconfig', moduleName='Mininet')

class Host( Node ):

"A host is simply a Node"

pass

class CPULimitedHost( Host ):

"CPU limited host"

def __init__( self, name, sched='cfs', **kwargs ):

Host.__init__( self, name, **kwargs )

# Initialize class if necessary

if not CPULimitedHost.inited:

CPULimitedHost.init()

# Create a cgroup and move shell into it

self.cgroup = 'cpu,cpuacct,cpuset:/' + self.name

errFail( 'cgcreate -g ' + self.cgroup )

# We don't add ourselves to a cpuset because you must

# specify the cpu and memory placement first

errFail( 'cgclassify -g cpu,cpuacct:/%s %s' % ( self.name, self.pid ) )

# BL: Setting the correct period/quota is tricky, particularly

# for RT. RT allows very small quotas, but the overhead

# seems to be high. CFS has a mininimum quota of 1 ms, but

# still does better with larger period values.

self.period_us = kwargs.get( 'period_us', 100000 )

self.sched = sched

if sched == 'rt':

self.checkRtGroupSched()

self.rtprio = 20

def cgroupSet( self, param, value, resource='cpu' ):

"Set a cgroup parameter and return its value"

cmd = 'cgset -r %s.%s=%s /%s' % (

resource, param, value, self.name )

quietRun( cmd )

nvalue = int( self.cgroupGet( param, resource ) )

if nvalue != value:

error( '*** error: cgroupSet: %s set to %s instead of %s\n'

% ( param, nvalue, value ) )

return nvalue

def cgroupGet( self, param, resource='cpu' ):

"Return value of cgroup parameter"

cmd = 'cgget -r %s.%s /%s' % (

resource, param, self.name )

return int( quietRun( cmd ).split()[ -1 ] )

def cgroupDel( self ):

"Clean up our cgroup"

# info( '*** deleting cgroup', self.cgroup, '\n' )

_out, _err, exitcode = errRun( 'cgdelete -r ' + self.cgroup )

return exitcode != 0

def popen( self, *args, **kwargs ):

"""Return a Popen() object in node's namespace

args: Popen() args, single list, or string

kwargs: Popen() keyword args"""

# Tell mnexec to execute command in our cgroup

mncmd = [ 'mnexec', '-g', self.name,

'-da', str( self.pid ) ]

# if our cgroup is not given any cpu time,

# we cannot assign the RR Scheduler.

if self.sched == 'rt':

if int( self.cgroupGet( 'rt_runtime_us', 'cpu' ) ) <= 0:

mncmd += [ '-r', str( self.rtprio ) ]

else:

debug( '*** error: not enough cpu time available for %s.' %

self.name, 'Using cfs scheduler for subprocess\n' )

return Host.popen( self, *args, mncmd=mncmd, **kwargs )

def cleanup( self ):

"Clean up Node, then clean up our cgroup"

super( CPULimitedHost, self ).cleanup()

retry( retries=3, delaySecs=1, fn=self.cgroupDel )

_rtGroupSched = False # internal class var: Is CONFIG_RT_GROUP_SCHED set?

@classmethod

def checkRtGroupSched( cls ):

"Check (Ubuntu,Debian) kernel config for CONFIG_RT_GROUP_SCHED for RT"

if not cls._rtGroupSched:

release = quietRun( 'uname -r' ).strip('\r\n')

output = quietRun( 'grep CONFIG_RT_GROUP_SCHED /boot/config-%s' %

release )

if output == '# CONFIG_RT_GROUP_SCHED is not set\n':

error( '\n*** error: please enable RT_GROUP_SCHED '

'in your kernel\n' )

exit( 1 )

cls._rtGroupSched = True

def chrt( self ):

"Set RT scheduling priority"

quietRun( 'chrt -p %s %s' % ( self.rtprio, self.pid ) )

result = quietRun( 'chrt -p %s' % self.pid )

firstline = result.split( '\n' )[ 0 ]

lastword = firstline.split( ' ' )[ -1 ]

if lastword != 'SCHED_RR':

error( '*** error: could not assign SCHED_RR to %s\n' % self.name )

return lastword

def rtInfo( self, f ):

"Internal method: return parameters for RT bandwidth"

pstr, qstr = 'rt_period_us', 'rt_runtime_us'

# RT uses wall clock time for period and quota

quota = int( self.period_us * f )

return pstr, qstr, self.period_us, quota

def cfsInfo( self, f ):

"Internal method: return parameters for CFS bandwidth"

pstr, qstr = 'cfs_period_us', 'cfs_quota_us'

# CFS uses wall clock time for period and CPU time for quota.

quota = int( self.period_us * f * numCores() )

period = self.period_us

if f > 0 and quota < 1000:

debug( '(cfsInfo: increasing default period) ' )

quota = 1000

period = int( quota / f / numCores() )

# Reset to unlimited on negative quota

if quota < 0:

quota = -1

return pstr, qstr, period, quota

# BL comment:

# This may not be the right API,

# since it doesn't specify CPU bandwidth in "absolute"

# units the way link bandwidth is specified.

# We should use MIPS or SPECINT or something instead.

# Alternatively, we should change from system fraction

# to CPU seconds per second, essentially assuming that

# all CPUs are the same.

def setCPUFrac( self, f, sched=None ):

"""Set overall CPU fraction for this host

f: CPU bandwidth limit (positive fraction, or -1 for cfs unlimited)

sched: 'rt' or 'cfs'

Note 'cfs' requires CONFIG_CFS_BANDWIDTH,

and 'rt' requires CONFIG_RT_GROUP_SCHED"""

if not sched:

sched = self.sched

if sched == 'rt':

if not f or f < 0:

raise Exception( 'Please set a positive CPU fraction'

' for sched=rt\n' )

pstr, qstr, period, quota = self.rtInfo( f )

elif sched == 'cfs':

pstr, qstr, period, quota = self.cfsInfo( f )

else:

return

# Set cgroup's period and quota

setPeriod = self.cgroupSet( pstr, period )

setQuota = self.cgroupSet( qstr, quota )

if sched == 'rt':

# Set RT priority if necessary

sched = self.chrt()

info( '(%s %d/%dus) ' % ( sched, setQuota, setPeriod ) )

def setCPUs( self, cores, mems=0 ):

"Specify (real) cores that our cgroup can run on"

if not cores:

return

if isinstance( cores, list ):

cores = ','.join( [ str( c ) for c in cores ] )

self.cgroupSet( resource='cpuset', param='cpus',

value=cores )

# Memory placement is probably not relevant, but we

# must specify it anyway

self.cgroupSet( resource='cpuset', param='mems',

value=mems)

# We have to do this here after we've specified

# cpus and mems

errFail( 'cgclassify -g cpuset:/%s %s' % (

self.name, self.pid ) )

def config( self, cpu=-1, cores=None, **params ):

"""cpu: desired overall system CPU fraction

cores: (real) core(s) this host can run on

params: parameters for Node.config()"""

r = Node.config( self, **params )

# Was considering cpu={'cpu': cpu , 'sched': sched}, but

# that seems redundant

self.setParam( r, 'setCPUFrac', cpu=cpu )

self.setParam( r, 'setCPUs', cores=cores )

return r

inited = False

@classmethod

def init( cls ):

"Initialization for CPULimitedHost class"

mountCgroups()

cls.inited = True

# Some important things to note:

#

# The "IP" address which setIP() assigns to the switch is not

# an "IP address for the switch" in the sense of IP routing.

# Rather, it is the IP address for the control interface,

# on the control network, and it is only relevant to the

# controller. If you are running in the root namespace

# (which is the only way to run OVS at the moment), the

# control interface is the loopback interface, and you

# normally never want to change its IP address!

#

# In general, you NEVER want to attempt to use Linux's

# network stack (i.e. ifconfig) to "assign" an IP address or

# MAC address to a switch data port. Instead, you "assign"

# the IP and MAC addresses in the controller by specifying

# packets that you want to receive or send. The "MAC" address

# reported by ifconfig for a switch data port is essentially

# meaningless. It is important to understand this if you

# want to create a functional router using OpenFlow.

class Switch( Node ):

"""A Switch is a Node that is running (or has execed?)

an OpenFlow switch."""

portBase = 1 # Switches start with port 1 in OpenFlow

dpidLen = 16 # digits in dpid passed to switch

def __init__( self, name, dpid=None, opts='', listenPort=None, **params):

"""dpid: dpid hex string (or None to derive from name, e.g. s1 -> 1)

opts: additional switch options

listenPort: port to listen on for dpctl connections"""

Node.__init__( self, name, **params )

self.dpid = self.defaultDpid( dpid )

self.opts = opts

self.listenPort = listenPort

if not self.inNamespace:

self.controlIntf = Intf( 'lo', self, port=0 )

def defaultDpid( self, dpid=None ):

"Return correctly formatted dpid from dpid or switch name (s1 -> 1)"

if dpid:

# Remove any colons and make sure it's a good hex number

dpid = dpid.translate( None, ':' )

assert len( dpid ) <= self.dpidLen and int( dpid, 16 ) >= 0

else:

# Use hex of the first number in the switch name

nums = re.findall( r'\d+', self.name )

if nums:

dpid = hex( int( nums[ 0 ] ) )[ 2: ]

else:

raise Exception( 'Unable to derive default datapath ID - '

'please either specify a dpid or use a '

'canonical switch name such as s23.' )

return '0' * ( self.dpidLen - len( dpid ) ) + dpid

def defaultIntf( self ):

"Return control interface"

if self.controlIntf:

return self.controlIntf

else:

return Node.defaultIntf( self )

def sendCmd( self, *cmd, **kwargs ):

"""Send command to Node.

cmd: string"""

kwargs.setdefault( 'printPid', False )

if not self.execed:

return Node.sendCmd( self, *cmd, **kwargs )

else:

error( '*** Error: %s has execed and cannot accept commands' %

self.name )

def connected( self ):

"Is the switch connected to a controller? (override this method)"

# Assume that we are connected by default to whatever we need to

# be connected to. This should be overridden by any OpenFlow

# switch, but not by a standalone bridge.

debug( 'Assuming', repr( self ), 'is connected to a controller\n' )

return True

def __repr__( self ):

"More informative string representation"

intfs = ( ','.join( [ '%s:%s' % ( i.name, i.IP() )

for i in self.intfList() ] ) )

return '<%s %s: %s pid=%s> ' % (

self.__class__.__name__, self.name, intfs, self.pid )

class UserSwitch( Switch ):

"User-space switch."

dpidLen = 12

def __init__( self, name, dpopts='--no-slicing', **kwargs ):

"""Init.

name: name for the switch

dpopts: additional arguments to ofdatapath (--no-slicing)"""

Switch.__init__( self, name, **kwargs )

pathCheck( 'ofdatapath', 'ofprotocol',

moduleName='the OpenFlow reference user switch' +

'(openflow.org)' )

if self.listenPort:

self.opts += ' --listen=ptcp:%i ' % self.listenPort

else:

self.opts += ' --listen=punix:/tmp/%s.listen' % self.name

self.dpopts = dpopts

@classmethod

def setup( cls ):

"Ensure any dependencies are loaded; if not, try to load them."

if not os.path.exists( '/dev/net/tun' ):

moduleDeps( add=TUN )

def dpctl( self, *args ):

"Run dpctl command"

listenAddr = None

if not self.listenPort:

listenAddr = 'unix:/tmp/%s.listen' % self.name

else:

listenAddr = 'tcp:127.0.0.1:%i' % self.listenPort

return self.cmd( 'dpctl ' + ' '.join( args ) +

' ' + listenAddr )

def connected( self ):

"Is the switch connected to a controller?"

status = self.dpctl( 'status' )

return ( 'remote.is-connected=true' in status and

'local.is-connected=true' in status )

@staticmethod

def TCReapply( intf ):

"""Unfortunately user switch and Mininet are fighting

over tc queuing disciplines. To resolve the conflict,

we re-create the user switch's configuration, but as a

leaf of the TCIntf-created configuration."""

if isinstance( intf, TCIntf ):

ifspeed = 10000000000 # 10 Gbps

minspeed = ifspeed * 0.001

res = intf.config( **intf.params )

if res is None: # link may not have TC parameters

return

# Re-add qdisc, root, and default classes user switch created, but

# with new parent, as setup by Mininet's TCIntf

parent = res['parent']

intf.tc( "%s qdisc add dev %s " + parent +

" handle 1: htb default 0xfffe" )

intf.tc( "%s class add dev %s classid 1:0xffff parent 1: htb rate "

+ str(ifspeed) )

intf.tc( "%s class add dev %s classid 1:0xfffe parent 1:0xffff " +

"htb rate " + str(minspeed) + " ceil " + str(ifspeed) )

def start( self, controllers ):

"""Start OpenFlow reference user datapath.

Log to /tmp/sN-{ofd,ofp}.log.

controllers: list of controller objects"""

# Add controllers

clist = ','.join( [ 'tcp:%s:%d' % ( c.IP(), c.port )

for c in controllers ] )

ofdlog = '/tmp/' + self.name + '-ofd.log'

ofplog = '/tmp/' + self.name + '-ofp.log'

intfs = [ str( i ) for i in self.intfList() if not i.IP() ]

self.cmd( 'ofdatapath -i ' + ','.join( intfs ) +

' punix:/tmp/' + self.name + ' -d %s ' % self.dpid +

self.dpopts +

' 1> ' + ofdlog + ' 2> ' + ofdlog + ' &' )

self.cmd( 'ofprotocol unix:/tmp/' + self.name +

' ' + clist +

' --fail=closed ' + self.opts +

' 1> ' + ofplog + ' 2>' + ofplog + ' &' )

if "no-slicing" not in self.dpopts:

# Only TCReapply if slicing is enable

sleep(1) # Allow ofdatapath to start before re-arranging qdisc's

for intf in self.intfList():

if not intf.IP():

self.TCReapply( intf )

def stop( self, deleteIntfs=True ):

"""Stop OpenFlow reference user datapath.

deleteIntfs: delete interfaces? (True)"""

self.cmd( 'kill %ofdatapath' )

self.cmd( 'kill %ofprotocol' )

super( UserSwitch, self ).stop( deleteIntfs )