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1375 lines (1195 loc) · 51.7 KB
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"""
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.
CPULimitedHost: a virtual host whose CPU bandwidth is limited by
RT or CFS bandwidth limiting.
HostWithPrivateDirs: a virtual host that has user-specified private
directories. These may be temporary directories stored as a tmpfs,
or persistent directories that are mounted from another directory in
the root filesystem.
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, STDOUT
from operator import or_
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
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?
params: Node parameters (see config() for details)"""
# Make sure class actually works
self.checkSetup()
self.name = params.get( 'name', name )
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()
# 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' )
def _popen( self, cmd, **params ):
"""Internal method: spawn and return a process
cmd: command to run (list)
params: parameters to Popen()"""
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."
if self.shell and self.shell.returncode is not None:
os.killpg( self.pid, signal.SIGHUP )
self.cleanup()
def stop( self ):
"Stop node."
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', False )
# Allow sendCmd( [ list ] )
if len( args ) == 1 and type( args[ 0 ] ) is 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 printPid and not isShellBuiltin( cmd ):
if len( cmd ) > 0 and cmd[ -1 ] == '&':
# print ^A{pid}\n so monitor() can set lastPid
cmd += ' printf "\\001%d\n" $! \n'
else:
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 )
# Look for PID
marker = chr( 1 ) + r'\d+\r\n'
if findPid and chr( 1 ) in 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
8BD0
( 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()
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 type( args[ 0 ] ) is list:
# popen([cmd, arg1, arg2...])
cmd = args[ 0 ]
elif type( args[ 0 ] ) is str:
# 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, srcNode=None ):
"""Add an interface.
intf: interface
port: port number (optional, typically OpenFlow port number)"""
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 srcNode %s\n' % (
intf, port, self.name, srcNode ) )
if srcNode != self:
debug( 'moving', intf, 'into namespace for', self.name, '\n' )
moveIntf( intf.name, self, srcNode=srcNode )
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='' ):
"""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 type( intf ) is str:
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 type( intf ) is str and ' ' in intf:
params = intf
else:
params = 'dev %s' % intf
self.cmd( 'ip route del default' )
return self.cmd( '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 ]
f = getattr( self, method, None )
if not f or value is None:
return
if type( value ) is list:
result = f( *value )
elif type( value ) is 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
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', '-da', str( self.pid ),
'-g', self.name ]
if self.sched == 'rt':
mncmd += [ '-r', str( self.rtprio ) ]
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 )
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 * numCores() )
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() )
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=-1, sched=None):
"""Set overall CPU fraction for this host
f: CPU bandwidth limit (fraction)
sched: 'rt' or 'cfs'
Note 'cfs' requires CONFIG_CFS_BANDWIDTH"""
if not f:
return
if not sched:
sched = self.sched
if sched == 'rt':
pstr, qstr, period, quota = self.rtInfo( f )
elif sched == 'cfs':
pstr, qstr, period, quota = self.cfsInfo( f )
else:
return
if quota < 0:
# Reset to unlimited
quota = -1
# Set cgroup's period and quota
self.cgroupSet( pstr, period )
self.cgroupSet( qstr, quota )
if sched == 'rt':
# Set RT priority if necessary
self.chrt()
info( '(%s %d/%dus) ' % ( sched, quota, period ) )
def setCPUs( self, cores, mems=0 ):
"Specify (real) cores that our cgroup can run on"
if type( cores ) is 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=None, 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
class HostWithPrivateDirs( Host ):
"Host with private directories"
def __init__( self, name, *args, **kwargs ):
"privateDirs: list of private directory strings or tuples"
self.name = name
self.privateDirs = kwargs.pop( 'privateDirs', [] )
Host.__init__( self, name, *args, **kwargs )
self.mountPrivateDirs()
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 )
# 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)"
return False and self # satisfy pylint
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?"
return 'remote.is-connected=true' in self.dpctl( '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 type( intf ) is 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'
self.cmd( 'ifconfig lo up' )
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 ):
"Stop OpenFlow reference user datapath."
self.cmd( 'kill %ofdatapath' )
self.cmd( 'kill %ofprotocol' )
self.deleteIntfs()
class OVSLegacyKernelSwitch( Switch ):
"""Open VSwitch legacy kernel-space switch using ovs-openflowd.
Currently only works in the root namespace."""
def __init__( self, name, dp=None, **kwargs ):
"""Init.
name: name for switch
dp: netlink id (0, 1, 2, ...)
defaultMAC: default MAC as unsigned int; random value if None"""
Switch.__init__( self, name, **kwargs )
self.dp = dp if dp else self.name
self.intf = self.dp
if self.inNamespace:
error( "OVSKernelSwitch currently only works"
" in the root namespace.\n" )
exit( 1 )
@classmethod
def setup( cls ):
"Ensure any dependencies are loaded; if not, try to load them."
pathCheck( 'ovs-dpctl', 'ovs-openflowd',
moduleName='Open vSwitch (openvswitch.org)')
moduleDeps( subtract=OF_KMOD, add=OVS_KMOD )
def start( self, controllers ):
"Start up kernel datapath."
ofplog = '/tmp/' + self.name + '-ofp.log'
quietRun( 'ifconfig lo up' )
# Delete local datapath if it exists;
# then create a new one monitoring the given interfaces
self.cmd( 'ovs-dpctl del-dp ' + self.dp )
self.cmd( 'ovs-dpctl add-dp ' + self.dp )
intfs = [ str( i ) for i in self.intfList() if not i.IP() ]
self.cmd( 'ovs-dpctl', 'add-if', self.dp, ' '.join( intfs ) )
# Run protocol daemon
clist = ','.join( [ 'tcp:%s:%d' % ( c.IP(), c.port )
for c in controllers ] )
self.cmd( 'ovs-openflowd ' + self.dp +
' ' + clist +
' --fail=secure ' + self.opts +
' --datapath-id=' + self.dpid +