mininet/mininet/link.py at devel/nattedtopo · xer0xe9/mininet

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"""

link.py: interface and link abstractions for mininet

It seems useful to bundle functionality for interfaces into a single

class.

Also it seems useful to enable the possibility of multiple flavors of

links, including:

- simple veth pairs

- tunneled links

- patchable links (which can be disconnected and reconnected via a patchbay)

- link simulators (e.g. wireless)

Basic division of labor:

Nodes: know how to execute commands

Intfs: know how to configure themselves

Links: know how to connect nodes together

Intf: basic interface object that can configure itself

TCIntf: interface with bandwidth limiting and delay via tc

Link: basic link class for creating veth pairs

"""

from mininet.log import info, error, debug

from mininet.util import makeIntfPair

import mininet.node

import re

class Intf( object ):

"Basic interface object that can configure itself."

def __init__( self, name, node=None, port=None, link=None,

mac=None, **params ):

"""name: interface name (e.g. h1-eth0)

node: owning node (where this intf most likely lives)

link: parent link if we're part of a link

other arguments are passed to config()"""

self.node = node

self.name = name

self.link = link

self.mac = mac

self.ip, self.prefixLen = None, None

# if interface is lo, we know the ip is 127.0.0.1.

# This saves an ifconfig command per node

if self.name == 'lo':

self.ip = '127.0.0.1'

# Add to node (and move ourselves if necessary )

moveIntfFn = params.pop( 'moveIntfFn', None )

if moveIntfFn:

node.addIntf( self, port=port, moveIntfFn=moveIntfFn )

else:

node.addIntf( self, port=port )

# Save params for future reference

self.params = params

self.config( **params )

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

"Run a command in our owning node"

return self.node.cmd( *args, **kwargs )

def ifconfig( self, *args ):

"Configure ourselves using ifconfig"

return self.cmd( 'ifconfig', self.name, *args )

def setIP( self, ipstr, prefixLen=None ):

"""Set our IP address"""

# This is a sign that we should perhaps rethink our prefix

# mechanism and/or the way we specify IP addresses

if '/' in ipstr:

self.ip, self.prefixLen = ipstr.split( '/' )

return self.ifconfig( ipstr, 'up' )

else:

if prefixLen is None:

raise Exception( 'No prefix length set for IP address %s'

% ( ipstr, ) )

self.ip, self.prefixLen = ipstr, prefixLen

return self.ifconfig( '%s/%s' % ( ipstr, prefixLen ) )

def setMAC( self, macstr ):

"""Set the MAC address for an interface.

macstr: MAC address as string"""

self.mac = macstr

return ( self.ifconfig( 'down' ) +

self.ifconfig( 'hw', 'ether', macstr ) +

self.ifconfig( 'up' ) )

_ipMatchRegex = re.compile( r'\d+\.\d+\.\d+\.\d+' )

_macMatchRegex = re.compile( r'..:..:..:..:..:..' )

def updateIP( self ):

"Return updated IP address based on ifconfig"

# use pexec instead of node.cmd so that we dont read

# backgrounded output from the cli.

ifconfig, _err, _exitCode = self.node.pexec(

'ifconfig %s' % self.name )

ips = self._ipMatchRegex.findall( ifconfig )

self.ip = ips[ 0 ] if ips else None

return self.ip

def updateMAC( self ):

"Return updated MAC address based on ifconfig"

ifconfig = self.ifconfig()

macs = self._macMatchRegex.findall( ifconfig )

self.mac = macs[ 0 ] if macs else None

return self.mac

# Instead of updating ip and mac separately,

# use one ifconfig call to do it simultaneously.

# This saves an ifconfig command, which improves performance.

def updateAddr( self ):

"Return IP address and MAC address based on ifconfig."

ifconfig = self.ifconfig()

ips = self._ipMatchRegex.findall( ifconfig )

macs = self._macMatchRegex.findall( ifconfig )

self.ip = ips[ 0 ] if ips else None

self.mac = macs[ 0 ] if macs else None

return self.ip, self.mac

def IP( self ):

"Return IP address"

return self.ip

def MAC( self ):

"Return MAC address"

return self.mac

def isUp( self, setUp=False ):

"Return whether interface is up"

if setUp:

cmdOutput = self.ifconfig( 'up' )

# no output indicates success

if cmdOutput:

error( "Error setting %s up: %s " % ( self.name, cmdOutput ) )

return False

else:

return True

else:

return "UP" in self.ifconfig()

def rename( self, newname ):

"Rename interface"

self.ifconfig( 'down' )

result = self.cmd( 'ip link set', self.name, 'name', newname )

self.name = newname

self.ifconfig( 'up' )

return result

# 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 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, ifconfig=None,

up=True, **_params ):

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

mac: MAC address

ip: IP address

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, 'isUp', up=up )

self.setParam( r, 'ifconfig', ifconfig=ifconfig )

return r

def delete( self ):

"Delete interface"

self.cmd( 'ip link del ' + self.name )

# We used to do this, but it slows us down:

# if self.node.inNamespace:

# Link may have been dumped into root NS

# quietRun( 'ip link del ' + self.name )

def status( self ):

"Return intf status as a string"

links, _err, _result = self.node.pexec( 'ip link show' )

if self.name in links:

return "OK"

else:

return "MISSING"

def __repr__( self ):

return '<%s %s>' % ( self.__class__.__name__, self.name )

def __str__( self ):

return self.name

class TCIntf( Intf ):

"""Interface customized by tc (traffic control) utility

Allows specification of bandwidth limits (various methods)

as well as delay, loss and max queue length"""

# The parameters we use seem to work reasonably up to 1 Gb/sec

# For higher data rates, we will probably need to change them.

bwParamM 10BC8 ax = 1000

def bwCmds( self, bw=None, speedup=0, use_hfsc=False, use_tbf=False,

latency_ms=None, enable_ecn=False, enable_red=False ):

"Return tc commands to set bandwidth"

cmds, parent = [], ' root '

if bw and ( bw < 0 or bw > self.bwParamMax ):

error( 'Bandwidth limit', bw, 'is outside supported range 0..%d'

% self.bwParamMax, '- ignoring\n' )

elif bw is not None:

# BL: this seems a bit brittle...

if ( speedup > 0 and

self.node.name[0:1] == 's' ):

bw = speedup

# This may not be correct - we should look more closely

# at the semantics of burst (and cburst) to make sure we

# are specifying the correct sizes. For now I have used

# the same settings we had in the mininet-hifi code.

if use_hfsc:

cmds += [ '%s qdisc add dev %s root handle 5:0 hfsc default 1',

'%s class add dev %s parent 5:0 classid 5:1 hfsc sc '

+ 'rate %fMbit ul rate %fMbit' % ( bw, bw ) ]

elif use_tbf:

if latency_ms is None:

latency_ms = 15 * 8 / bw

cmds += [ '%s qdisc add dev %s root handle 5: tbf ' +

'rate %fMbit burst 15000 latency %fms' %

( bw, latency_ms ) ]

else:

cmds += [ '%s qdisc add dev %s root handle 5:0 htb default 1',

'%s class add dev %s parent 5:0 classid 5:1 htb ' +

'rate %fMbit burst 15k' % bw ]

parent = ' parent 5:1 '

# ECN or RED

if enable_ecn:

cmds += [ '%s qdisc add dev %s' + parent +

'handle 6: red limit 1000000 ' +

'min 30000 max 35000 avpkt 1500 ' +

'burst 20 ' +

'bandwidth %fmbit probability 1 ecn' % bw ]

parent = ' parent 6: '

elif enable_red:

cmds += [ '%s qdisc add dev %s' + parent +

'handle 6: red limit 1000000 ' +

'min 30000 max 35000 avpkt 1500 ' +

'burst 20 ' +

'bandwidth %fmbit probability 1' % bw ]

parent = ' parent 6: '

return cmds, parent

@staticmethod

def delayCmds( parent, delay=None, jitter=None,

loss=None, max_queue_size=None ):

"Internal method: return tc commands for delay and loss"

cmds = []

if delay and delay < 0:

error( 'Negative delay', delay, '\n' )

elif jitter and jitter < 0:

error( 'Negative jitter', jitter, '\n' )

elif loss and ( loss < 0 or loss > 100 ):

error( 'Bad loss percentage', loss, '%%\n' )

else:

# Delay/jitter/loss/max queue size

netemargs = '%s%s%s%s' % (

'delay %s ' % delay if delay is not None else '',

'%s ' % jitter if jitter is not None else '',

'loss %d ' % loss if loss is not None else '',

'limit %d' % max_queue_size if max_queue_size is not None

else '' )

if netemargs:

cmds = [ '%s qdisc add dev %s ' + parent +

' handle 10: netem ' +

netemargs ]

parent = ' parent 10:1 '

return cmds, parent

def tc( self, cmd, tc='tc' ):

"Execute tc command for our interface"

c = cmd % (tc, self) # Add in tc command and our name

debug(" *** executing command: %s\n" % c)

return self.cmd( c )

def config( self, bw=None, delay=None, jitter=None, loss=None,

disable_gro=True, speedup=0, use_hfsc=False, use_tbf=False,

latency_ms=None, enable_ecn=False, enable_red=False,

max_queue_size=None, **params ):

"Configure the port and set its properties."

result = Intf.config( self, **params)

# Disable GRO

if disable_gro:

self.cmd( 'ethtool -K %s gro off' % self )

# Optimization: return if nothing else to configure

# Question: what happens if we want to reset things?

if ( bw is None and not delay and not loss

and max_queue_size is None ):

return

# Clear existing configuration

tcoutput = self.tc( '%s qdisc show dev %s' )

if "priomap" not in tcoutput:

cmds = [ '%s qdisc del dev %s root' ]

else:

cmds = []

# Bandwidth limits via various methods

bwcmds, parent = self.bwCmds( bw=bw, speedup=speedup,

use_hfsc=use_hfsc, use_tbf=use_tbf,

latency_ms=latency_ms,

enable_ecn=enable_ecn,

enable_red=enable_red )

cmds += bwcmds

# Delay/jitter/loss/max_queue_size using netem

delaycmds, parent = self.delayCmds( delay=delay, jitter=jitter,

loss=loss,

max_queue_size=max_queue_size,

parent=parent )

cmds += delaycmds

# Ugly but functional: display configuration info

stuff = ( ( [ '%.2fMbit' % bw ] if bw is not None else [] ) +

( [ '%s delay' % delay ] if delay is not None else [] ) +

( [ '%s jitter' % jitter ] if jitter is not None else [] ) +

( ['%d%% loss' % loss ] if loss is not None else [] ) +

( [ 'ECN' ] if enable_ecn else [ 'RED' ]

if enable_red else [] ) )

info( '(' + ' '.join( stuff ) + ') ' )

# Execute all the commands in our node

debug("at map stage w/cmds: %s\n" % cmds)

tcoutputs = [ self.tc(cmd) for cmd in cmds ]

for output in tcoutputs:

if output != '':

error( "*** Error: %s" % output )

debug( "cmds:", cmds, '\n' )

debug( "outputs:", tcoutputs, '\n' )

result[ 'tcoutputs'] = tcoutputs

result[ 'parent' ] = parent

return result

class Link( object ):

"""A basic link is just a veth pair.

Other types of links could be tunnels, link emulators, etc.."""

# pylint: disable=too-many-branches

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

intfName1=None, intfName2=None, addr1=None, addr2=None,

intf=Intf, cls1=None, cls2=None, params1=None,

params2=None, fast=True ):

"""Create veth link to another node, making two new interfaces.

node1: first node

node2: second node

port1: node1 port number (optional)

port2: node2 port number (optional)

intf: default interface class/constructor

cls1, cls2: optional interface-specific constructors

intfName1: node1 interface name (optional)

intfName2: node2 interface name (optional)

params1: parameters for interface 1

params2: parameters for interface 2"""

# This is a bit awkward; it seems that having everything in

# params is more orthogonal, but being able to specify

# in-line arguments is more convenient! So we support both.

if params1 is None:

params1 = {}

if params2 is None:

params2 = {}

# Allow passing in params1=params2

if params2 is params1:

params2 = dict( params1 )

if port1 is not None:

params1[ 'port' ] = port1

if port2 is not None:

params2[ 'port' ] = port2

if 'port' not in params1:

params1[ 'port' ] = node1.newPort()

if 'port' not in params2:

params2[ 'port' ] = node2.newPort()

if not intfName1:

intfName1 = self.intfName( node1, params1[ 'port' ] )

if not intfName2:

intfName2 = self.intfName( node2, params2[ 'port' ] )

self.fast = fast

if fast:

params1.setdefault( 'moveIntfFn', self._ignore )

params2.setdefault( 'moveIntfFn', self._ignore )

self.makeIntfPair( intfName1, intfName2, addr1, addr2,

node1, node2, deleteIntfs=False )

else:

self.makeIntfPair( intfName1, intfName2, addr1, addr2 )

if not cls1:

cls1 = intf

if not cls2:

cls2 = intf

intf1 = cls1( name=intfName1, node=node1,

link=self, mac=addr1, **params1 )

intf2 = cls2( name=intfName2, node=node2,

link=self, mac=addr2, **params2 )

# All we are is dust in the wind, and our two interfaces

self.intf1, self.intf2 = intf1, intf2

# pylint: enable=too-many-branches

@staticmethod

def _ignore( *args, **kwargs ):

"Ignore any arguments"

pass

def intfName( self, node, n ):

"Construct a canonical interface name node-ethN for interface n."

# Leave this as an instance method for now

assert self

return node.name + '-eth' + repr( n )

@classmethod

def makeIntfPair( cls, intfname1, intfname2, addr1=None, addr2=None,

node1=None, node2=None, deleteIntfs=True ):

"""Create pair of interfaces

intfname1: name for interface 1

intfname2: name for interface 2

addr1: MAC address for interface 1 (optional)

addr2: MAC address for interface 2 (optional)

node1: home node for interface 1 (optional)

node2: home node for interface 2 (optional)

(override this method [and possibly delete()]

to change link type)"""

# Leave this as a class method for now

assert cls

return makeIntfPair( intfname1, intfname2, addr1, addr2, node1, node2,

deleteIntfs=deleteIntfs )

def delete( self ):

"Delete this link"

self.intf1.delete()

# We only need to delete one side, though this doesn't seem to

# cost us much and might help subclasses.

# self.intf2.delete()

def stop( self ):

"Override to stop and clean up link as needed"

self.delete()

def status( self ):

"Return link status as a string"

return "(%s %s)" % ( self.intf1.status(), 617D self.intf2.status() )

def __str__( self ):

return '%s<->%s' % ( self.intf1, self.intf2 )

class OVSIntf( Intf ):

"Patch interface on an OVSSwitch"

def ifconfig( self, *args ):

cmd = ' '.join( args )

if cmd == 'up':

# OVSIntf is always up

return

else:

raise Exception( 'OVSIntf cannot do ifconfig ' + cmd )

class OVSLink( Link ):

"""Link that makes patch links between OVSSwitches

Warning: in testing we have found that no more

than ~64 OVS patch links should be used in row."""

def __init__( self, node1, node2, **kwargs ):

"See Link.__init__() for options"

self.isPatchLink = False

if ( isinstance( node1, mininet.node.OVSSwitch ) and

isinstance( node2, mininet.node.OVSSwitch ) ):

self.isPatchLink = True

kwargs.update( cls1=OVSIntf, cls2=OVSIntf )

Link.__init__( self, node1, node2, **kwargs )

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

"Usually delegated to OVSSwitch"

if self.isPatchLink:

return None, None

else:

return Link.makeIntfPair( *args, **kwargs )

class TCLink( Link ):

"Link with symmetric TC interfaces configured via opts"

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

intfName1=None, intfName2=None,

addr1=None, addr2=None, **params ):

Link.__init__( self, node1, node2, port1=port1, port2=port2,

intfName1=intfName1, intfName2=intfName2,

cls1=TCIntf,

cls2=TCIntf,

addr1=addr1, addr2=addr2,

params1=params,

params2=params )

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