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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, quietRun
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'
self.prefixLen = 8
# Add to node (and move ourselves if necessary )
if node:
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 )
self.node.delIntf( self )
self.link = None
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.
bwParamMax = 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 = 15.0 * 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 %.5f ' % 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,
gro=False, txo=True, rxo=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.
bw: bandwidth in b/s (e.g. '10m')
delay: transmit delay (e.g. '1ms' )
jitter: jitter (e.g. '1ms')
loss: loss (e.g. '1%' )
gro: enable GRO (False)
txo: enable transmit checksum offload (True)
rxo: enable receive checksum offload (True)
speedup: experimental switch-side bw option
use_hfsc: use HFSC scheduling
use_tbf: use TBF scheduling
latency_ms: TBF latency parameter
enable_ecn: enable ECN (False)
enable_red: enable RED (False)
max_queue_size: queue limit parameter for netem"""
# Support old names for parameters
gro = not params.pop( 'disable_gro', not gro )
result = Intf.config( self, **params)
def on( isOn ):
"Helper method: bool -> 'on'/'off'"
return 'on' if isOn else 'off'
# Set offload parameters with ethool
self.cmd( 'ethtool -K', self,
'gro', on( gro ),
'tx', on( txo ),
'rx', on( rxo ) )
# 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 and "noqueue" 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 [] ) +
( ['%.5f%% 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,
runCmd=quietRun ):
"""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, runCmd=runCmd )
def delete( self ):
"Delete this link"
self.intf1.delete()
self.intf1 = None
self.intf2.delete()
self.intf2 = None
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(), 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"
from mininet.node import OVSSwitch
self.isPatchLink = False
if ( isinstance( node1, OVSSwitch ) and
isinstance( node2, 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 )
class TCULink( TCLink ):
"""TCLink with default settings optimized for UserSwitch
(txo=rxo=0/False). Unfortunately with recent Linux kernels,
enabling TX and RX checksum offload on veth pairs doesn't work
well with UserSwitch: either it gets terrible performance or
TCP packets with bad checksums are generated, forwarded, and
*dropped* due to having bad checksums! OVS and LinuxBridge seem
to cope with this somehow, but it is likely to be an issue with
many software Ethernet bridges."""
def __init__( self, *args, **kwargs ):
kwargs.update( txo=False, rxo=False )
TCLink.__init__( self, *args, **kwargs )