Files
mininet/mininet/link.py
T
Bob Lantz c265deedef Cluster edition prototype: remote nodes and links.
We add a new experimental feature to allow Mininet to run across
a cluster of machines. This is currently implemented via a set
mix-in classes that provide remote nodes that are implemented
via a connection to a remote shell, and remote links which are
tunnels across servers. In this preliminary implementation,
both control and data connections are made via ssh, but this
could change in the future.

A MininetCluster class is provided which allows existing code
to be used with minimal modification - all that is required is
to provide a list of servers to use. A customizable placement
algorithm may also be specified. An experimental CLI subclass
is also provided to make it easier to examine node placement;
status and links commands can also check whether nodes and
tunnels are still running.

Although this is an experimental feature, it does include a
--cluster option to make it convenient to start up a Mininet
simulation over a cluster, and a script to assist with setting
up the prerequisite authentication via ssh key pairs.

The cluster feature is preliminary and missing some obvious
important features, such as parallel startup and multiple tunnel
types, which we hope to add in the future.
2014-09-04 23:07:01 -07:00

457 lines
17 KiB
Python

"""
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 re
class Intf( object ):
"Basic interface object that can configure itself."
def __init__( self, name, node=None, port=None, link=None,
mac=None, srcNode=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 )
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:
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"
ifconfig = self.ifconfig()
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 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, 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 )
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"""
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 > 1000 ):
error( 'Bandwidth', bw, 'is outside range 0..1000 Mbps\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.."""
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 ):
"""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.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
def intfName( _self, node, n ):
"Construct a canonical interface name node-ethN for interface n."
return node.name + '-eth' + repr( n )
@classmethod
def makeIntfPair( _cls, intfname1, intfname2, addr1=None, addr2=None ):
"""Create pair of interfaces
intfname1: name of interface 1
intfname2: name of interface 2
(override this method [and possibly delete()]
to change link type)"""
return makeIntfPair( intfname1, intfname2, addr1, addr2 )
def delete( self ):
"Delete this link"
self.intf1.delete()
self.intf2.delete()
def stop( self ):
"Override to stop and clean up link as needed"
pass
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 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 )