Fix codecheck and MininetWithControlNet.

mininet/cli.py

@@ -77,7 +77,7 @@ class CLI( Cmd ):
     # Disable pylint "Unused argument: 'arg's'" messages, as well as
     # "method could be a function" warning, since each CLI function
     # must have the same interface
-    # pylint: disable-msg=W0613,R0201
+    # pylint: disable-msg=R0201
 
     helpStr = (
         'You may also send a command to a node using:\n'
@@ -104,12 +104,12 @@ class CLI( Cmd ):
         if line is '':
             output( self.helpStr )
 
-    def do_nodes( self, line ):
+    def do_nodes( self, _line ):
         "List all nodes."
         nodes = ' '.join( [ node.name for node in sorted( self.nodelist ) ] )
         output( 'available nodes are: \n%s\n' % nodes )
 
-    def do_net( self, line ):
+    def do_net( self, _line ):
         "List network connections."
         for switch in self.mn.switches:
             output( switch.name, '<->' )
@@ -143,11 +143,11 @@ class CLI( Cmd ):
 
     # pylint: enable-msg=W0703
 
-    def do_pingall( self, line ):
+    def do_pingall( self, _line ):
         "Ping between all hosts."
         self.mn.pingAll()
 
-    def do_pingpair( self, line ):
+    def do_pingpair( self, _line ):
         "Ping between first two hosts, useful for testing."
         self.mn.pingPair()
 
@@ -191,13 +191,13 @@ class CLI( Cmd ):
             error( 'invalid number of args: iperfudp bw src dst\n' +
                    'bw examples: 10M\n' )
 
-    def do_intfs( self, line ):
+    def do_intfs( self, _line ):
         "List interfaces."
         for node in self.nodelist:
             output( '%s: %s\n' %
                 ( node.name, ' '.join( sorted( node.intfs.values() ) ) ) )
 
-    def do_dump( self, line ):
+    def do_dump( self, _line ):
         "Dump node info."
         for node in self.nodelist:
             output( '%s\n' % node )
@@ -229,7 +229,7 @@ class CLI( Cmd ):
         "Spawn gnome-terminal(s) for the given node(s)."
         self.do_xterm( line, term='gterm' )
 
-    def do_exit( self, line ):
+    def do_exit( self, _line ):
         "Exit"
         return 'exited by user command'
 
@@ -311,7 +311,7 @@ class CLI( Cmd ):
         else:
             error( '*** Unknown command: %s\n' % first )
 
-    # pylint: enable-msg=W0613,R0201
+    # pylint: enable-msg=R0201
 
     def waitForNode( self, node ):
         "Wait for a node to finish, and  print its output."

mininet/link.py

@@ -41,30 +41,35 @@ class Intf( object ):
         self.node = node
         self.name = name
         self.link = link
-        self.mac, self.ip = None, None
+        self.mac, self.ip, self.prefixLen = None, None, None
         # Add to node (and move ourselves if necessary )
         node.addIntf( self )
         self.config( **kwargs )
 
     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 ):
+    def setIP( self, ipstr, prefixLen=None ):
         """Set our IP address"""
         # This is a sign that we should perhaps rethink our prefix
-        # mechanism
-        self.ip, self.prefixLen = ipstr.split( '/' )
-        return self.ifconfig( ipstr, 'up' )
+        # 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' ) + 
+        return ( self.ifconfig( 'down' ) +
                  self.ifconfig( 'hw', 'ether', macstr ) +
                  self.ifconfig( 'up' ) )
 
@@ -78,13 +83,13 @@ class Intf( object ):
         self.ip = ips[ 0 ] if ips else None
         return self.ip
 
-    def updateMAC( self, intf ):
+    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
-    
+
     def IP( self ):
         "Return IP address"
         return self.ip
@@ -93,9 +98,9 @@ class Intf( object ):
         "Return MAC address"
         return self.mac
 
-    def isUp( self, set=False ):
+    def isUp( self, setUp=False ):
         "Return whether interface is up"
-        if set:
+        if setUp:
             self.ifconfig( 'up' )
         return "UP" in self.ifconfig()
 
@@ -124,8 +129,8 @@ class Intf( object ):
         results[ name ] = result
         return result
 
-    def config( self, mac=None, ip=None, ifconfig=None, 
-                defaultRoute=None, up=True, **params):
+    def config( self, mac=None, ip=None, ifconfig=None,
+                up=True, **_params ):
         """Configure Node according to (optional) parameters:
            mac: MAC address
            ip: IP address
@@ -153,7 +158,83 @@ class Intf( object ):
 
 
 class TCIntf( Intf ):
-    "Interface customized by tc (traffic control) utility"  
+    """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,
+                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[0:2] == 'sw' ):
+                bw = speedup
+            if use_hfsc:
+                cmds = [ '%s qdisc add dev %s root handle 1:0 hfsc default 1',
+                          'class add dev %s parent 1:0 classid 1:1 hfsc sc '
+                          + 'rate %fMbit ul rate %fMbit' % ( bw, bw ) ]
+            elif use_tbf:
+                latency_us = 10 * 1500 * 8 / bw
+                cmds = ['%s qdisc add dev %s root handle 1: tbf ' +
+                        'rate %fMbit burst 15000 latency %fus' %
+                         (bw, latency_us) ]
+            else:
+                cmds = [ '%s qdisc add dev %s root handle 1:0 htb default 1',
+                         '%s class add dev %s parent 1:0 classid 1:1 htb ' +
+                         'rate %fMbit burst 15k' % bw ]
+            parent = ' parent 1:1 '
+
+            # ECN or RED
+            if enable_ecn:
+                cmds = [ '%s qdisc add dev %s' + parent +
+                          'handle 10: red limit 1000000 ' +
+                          'min 20000 max 25000 avpkt 1000 ' +
+                          'burst 20 ' +
+                          'bandwidth %fmbit probability 1 ecn' % bw ]
+                parent = ' parent 10: '
+            elif enable_red:
+                cmds = [ '%s qdisc add dev %s' + parent +
+                          'handle 10: red limit 1000000 ' +
+                          'min 20000 max 25000 avpkt 1000 ' +
+                          'burst 20 ' +
+                          'bandwidth %fmbit probability 1' % bw ]
+                parent = ' parent 10: '
+
+        return cmds, parent
+
+    @staticmethod
+    def delayCmds( parent, delay=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 loss and ( loss < 0 or loss > 100 ):
+            error( 'Bad loss percentage', loss, '%%\n' )
+        else:
+            # Delay/loss/max queue size
+            netemargs = '%s%s%s' % (
+                'delay %s ' % delay if delay 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 + ' netem ' +
+                          netemargs ]
+        return cmds
+
+    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, loss=None, disable_gro=True,
                 speedup=0, use_hfsc=False, use_tbf=False, enable_ecn=False,
@@ -162,106 +243,58 @@ class TCIntf( Intf ):
 
         result = Intf.config( self, **params)
 
-        # disable GRO
+        # Disable GRO
         if disable_gro:
             self.cmd( 'ethtool -K %s gro off' % self )
-        
-        if ( bw is None and not delay and not loss 
+
+        # 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
 
-        if bw and ( bw < 0 or bw > 1000 ):
-            error( 'Bandwidth', bw, 'is outside range 0..1000 Mbps\n' )
-            return
-            
-        if delay and delay < 0:
-            error( 'Negative delay', delay, '\n' )
-            return
+        # Clear existing configuration
+        cmds = [ '%s qdisc del dev %s root' ]
 
-        if loss and ( loss < 0 or loss > 100 ):
-            error( 'Bad loss percentage', loss, '%%\n' )
-            return
+        # Bandwidth limits via various methods
+        bwcmds, parent = self.bwCmds( bw=bw, speedup=speedup,
+                                 use_hfsc=use_hfsc, use_tbf=use_tbf,
+                                 enable_ecn=enable_ecn,
+                                 enable_red=enable_red )
+        cmds += bwcmds
 
-        # Ugly but functional
+        # Delay/loss/max_queue_size using netem
+        cmds += self.delayCmds( delay=delay, loss=loss,
+                                 max_queue_size=max_queue_size,
+                                 parent=parent )
+
+        # Ugly but functional: display configuration info
         stuff = ( ( [ '%.2fMbit' % bw ] if bw is not None else [] ) +
                   ( [ '%s delay' % delay ] if delay is not None else [] ) +
                   ( ['%d%% loss' % loss ] if loss is not None else [] ) +
-                  ( [ 'ECN' ] if enable_ecn  else [ 'RED' ] if enable_red else [] ) )
+                  ( [ 'ECN' ] if enable_ecn  else [ 'RED' ]
+                    if enable_red else [] ) )
         info( '(' + ' '.join( stuff ) + ') ' )
 
-        cmds = [ '%s qdisc del dev %s root' ]
-
-        tc = 'tc' # was getCmd( 'tc' )
-
-        # Bandwidth control algorithms
-        if bw is None:
-            parent = ' root '
-        else:
-            parent = ' parent 1:1 '
-            # BL: hmm... this seems a bit brittle
-            if speedup > 0 and self.node.name[0:2] == 'sw':
-                bw = speedup
-            if use_hfsc:
-                cmds += [ '%s qdisc add dev %s root handle 1:0 hfsc default 1',
-                          '%s class add dev %s parent 1:0 classid 1:1 hfsc sc ' +
-                                'rate %fMbit ul rate %fMbit' % ( bw, bw ) ]
-            elif use_tbf:
-                latency_us = 10 * 1500 * 8 / bw
-                cmds += ['%s qdisc add dev %s root handle 1: tbf ' +
-                        'rate %fMbit burst 15000 latency %fus' % (bw, latency_us) ]
-            else:
-                cmds += [ '%s qdisc add dev %s root handle 1:0 htb default 1',
-                         '%s class add dev %s parent 1:0 classid 1:1 htb ' +
-                         'rate %fMbit burst 15k' % bw ]
-            parent = ' parent 1:1 '
-
-            # ECN or RED
-            if enable_ecn:
-                cmds += [ '%s qdisc add dev %s' + parent +
-                          'handle 10: red limit 1000000 '+
-                          'min 20000 max 25000 avpkt 1000 '+
-                          'burst 20 '+
-                          'bandwidth %fmbit probability 1 ecn' % bw ]
-                parent = ' parent 10: '
-            elif enable_red:
-                cmds += [ '%s qdisc add dev %s' + parent +
-                          'handle 10: red limit 1000000 '+
-                          'min 20000 max 25000 avpkt 1000 '+
-                          'burst 20 '+
-                          'bandwidth %fmbit probability 1' % bw ]
-                parent = ' parent 10: '
-            
-        # Delay/loss/max queue size
-        netemargs = '%s%s%s' % (
-            'delay %s ' % delay if delay 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 + ' netem ' + 
-                      netemargs ]
-
-        # Execute all the commands in the container
+        # Execute all the commands in our node
         debug("at map stage w/cmds: %s\n" % cmds)
-        
-        def doConfigPort(s):
-            c = s % (tc, self)
-            debug(" *** executing command: %s\n" % c)
-            return self.cmd(c)
-        
-        tcoutputs = [ doConfigPort(cmd) for cmd in cmds ]
+        tcoutputs = [ self.tc(cmd) for cmd in cmds ]
         debug( "cmds:", cmds, '\n' )
         debug( "outputs:", tcoutputs, '\n' )
         result[ 'tcoutputs'] = tcoutputs
+
         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,
-                  intf=Intf, cls1=None, cls2=None, params1={}, params2={} ):
+    def __init__( self, node1, node2, port1=None, port2=None,
+                  intfName1=None, intfName2=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
@@ -284,13 +317,21 @@ class Link( object ):
             intfName1 = self.intfName( node1, port1 )
         if not intfName2:
             intfName2 = self.intfName( node2, port2 )
+
         self.makeIntfPair( intfName1, intfName2 )
+
         if not cls1:
             cls1 = intf
         if not cls2:
             cls2 = intf
+        if not params1:
+            params1 = {}
+        if not params2:
+            params2 = {}
+
         intf1 = cls1( name=intfName1, node=node1, link=self, **params1  )
         intf2 = cls2( name=intfName2, node=node2, link=self, **params2 )
+
         # All we are is dust in the wind, and our two interfaces
         self.intf1, self.intf2 = intf1, intf2
 
@@ -304,7 +345,8 @@ class Link( object ):
         """Create pair of interfaces
            intf1: name of interface 1
            intf2: name of interface 2
-           (override this class method [and possibly delete()] to change link type)"""
+           (override this class method [and possibly delete()]
+           to change link type)"""
         makeIntfPair( intf1, intf2  )
 
     def delete( self ):

mininet/net.py

@@ -104,7 +104,7 @@ class Mininet( object ):
     "Network emulation with hosts spawned in network namespaces."
 
     def __init__( self, topo=None, switch=OVSKernelSwitch, host=Host,
-                 controller=Controller, link=Link, intf=None, 
+                 controller=Controller, link=Link, intf=None,
                  build=True, xterms=False, cleanup=False, ipBase='10.0.0.0/8',
                  inNamespace=False,
                  autoSetMacs=False, autoStaticArp=False, listenPort=None ):
@@ -176,7 +176,7 @@ class Mininet( object ):
            switch: custom switch constructor (optional)
            returns: added switch
            side effect: increments listenPort ivar ."""
-        defaults = { 'listenPort': self.listenPort, 
+        defaults = { 'listenPort': self.listenPort,
                      'inNamespace': self.inNamespace }
         defaults.update( params )
         if not switch:
@@ -229,7 +229,7 @@ class Mininet( object ):
                                         ipBaseNum=ipBaseNum,
                                         prefixLen=prefixLen ) }
             if self.autoSetMacs:
-                defaults[ 'mac'] = macColonHex( nodeId ) 
+                defaults[ 'mac'] = macColonHex( nodeId )
             defaults.update( ni.params )
             node = addMethod( name, cls=ni.cls, **defaults )
             self.idToNode[ nodeId ] = node
@@ -275,17 +275,16 @@ class Mininet( object ):
 
         info( '\n' )
 
-
     def configureControlNetwork( self ):
-        error( "configureControlNetwork: override in subclass, or use" 
-               "MininetWithControlNet class" )
+        "Control net config hook: override in subclass"
+        raise Exception( 'configureControlNetwork: '
+               'should be overriden in subclass', self )
 
     def build( self ):
         "Build mininet."
         if self.topo:
             self.buildFromTopo( self.topo )
-        if self.inNamespace:
-            info( '*** Configuring control network\n' )
+        if ( self.inNamespace ):
             self.configureControlNetwork()
         info( '*** Configuring hosts\n' )
         self.configHosts()
@@ -533,7 +532,7 @@ class Mininet( object ):
         return result
 
     inited = False
-    
+
     @classmethod
     def init( cls ):
         "Initialize Mininet"
@@ -541,7 +540,8 @@ class Mininet( object ):
             return
         if os.getuid() != 0:
             # Note: this script must be run as root
-            # Perhaps we should do so automatically!
+            # Probably we should only sudo when we need
+            # to as per Big Switch's patch
             print "*** Mininet must run as root."
             exit( 1 )
         fixLimits()
@@ -570,7 +570,11 @@ class MininetWithControlNet( Mininet ):
           network (since real networks may need one!)
 
        5. Basically nobody ever used this code, so it has been moved
-          into its own class."""
+          into its own class.
+
+       6. Ultimately we may wish to extend this to allow us to create a
+          control network which every node's control interface is
+          attached to."""
 
     def configureControlNetwork( self ):
         "Configure control network."
@@ -589,27 +593,27 @@ class MininetWithControlNet( Mininet ):
         snum = ipParse( ip )
         for switch in self.switches:
             info( ' ' + switch.name )
-            sintf, cintf = self.link( switch, controller )
+            link = self.link( switch, controller, port1=0 )
+            sintf, cintf = link.intf1, link.intf2
+            switch.controlIntf = sintf
             snum += 1
             while snum & 0xff in [ 0, 255 ]:
                 snum += 1
             sip = ipStr( snum )
-            controller.setIP( cintf, cip, prefixLen )
-            switch.setIP( sintf, sip, prefixLen )
+            cintf.setIP( cip, prefixLen )
+            sintf.setIP( sip, prefixLen )
             controller.setHostRoute( sip, cintf )
             switch.setHostRoute( cip, sintf )
         info( '\n' )
         info( '*** Testing control network\n' )
-        while not controller.intfIsUp( cintf ):
+        while not cintf.isUp():
             info( '*** Waiting for', cintf, 'to come up\n' )
             sleep( 1 )
         for switch in self.switches:
-            while not switch.intfIsUp( sintf ):
+            while not sintf.isUp():
                 info( '*** Waiting for', sintf, 'to come up\n' )
                 sleep( 1 )
             if self.ping( hosts=[ switch, controller ] ) != 0:
                 error( '*** Error: control network test failed\n' )
                 exit( 1 )
         info( '\n' )
-
-

mininet/node.py

@@ -81,8 +81,14 @@ class Node( object ):
                          # 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.shell = None
         self.startShell()
 
     # File descriptor to node mapping support
@@ -99,28 +105,6 @@ class Node( object ):
         node = cls.outToNode.get( fd )
         return node or cls.inToNode.get( fd )
 
-    # 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')
-
-    def cleanup( self ):
-        "Help python collect its garbage."
-        self.shell = None
-
     # Command support via shell process in namespace
 
     def startShell( self ):
@@ -129,7 +113,7 @@ class Node( object ):
             error( "%s: shell is already running" )
             return
         # mnexec: (c)lose descriptors, (d)etach from tty,
-        # (p)rint pid, and run in (n)amespace 
+        # (p)rint pid, and run in (n)amespace
         opts = '-cdp'
         if self.inNamespace:
             opts += 'n'
@@ -153,19 +137,23 @@ class Node( object ):
         self.readbuf = ''
         self.waiting = False
 
-    def read( self, bytes=1024 ):
+    def cleanup( self ):
+        "Help python collect its garbage."
+        self.shell = None
+
+    def read( self, maxbytes=1024 ):
         """Buffered read from node, non-blocking.
-           bytes: maximum number of bytes to return"""
+           maxbytes: maximum number of bytes to return"""
         count = len( self.readbuf )
-        if count < bytes:
-            data = os.read( self.stdout.fileno(), bytes - count )
+        if count < maxbytes:
+            data = os.read( self.stdout.fileno(), maxbytes - count )
             self.readbuf += data
-        if bytes >= len( self.readbuf ):
+        if maxbytes >= len( self.readbuf ):
             result = self.readbuf
             self.readbuf = ''
         else:
-            result = self.readbuf[ :bytes ]
-            self.readbuf = self.readbuf[ bytes: ]
+            result = self.readbuf[ :maxbytes ]
+            self.readbuf = self.readbuf[ maxbytes: ]
         return result
 
     def readline( self ):
@@ -307,7 +295,7 @@ class Node( object ):
         self.ports[ intf ] = port
         self.nameToIntf[ intf.name ] = intf
         debug( '\n' )
-        debug( 'added intf %s:%d to node %s\n' % ( intf,port, self.name ) )
+        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' )
             moveIntf( intf.name, self )
@@ -363,7 +351,7 @@ class Node( object ):
         """Add route to host.
            ip: IP address as dotted decimal
            intf: string, interface name"""
-        return self.cmd( 'route add -host ' + ip + ' dev ' + intf )
+        return self.cmd( 'route add -host', ip, 'dev', intf )
 
     def setDefaultRoute( self, intf=None ):
         """Set the default route to go through intf.
@@ -430,8 +418,8 @@ class Node( object ):
         results[ name ] = result
         return result
 
-    def config( self, mac=None, ip=None, ifconfig=None, 
-                defaultRoute=None, **params):
+    def config( self, mac=None, ip=None, ifconfig=None,
+                defaultRoute=None, **_params ):
         """Configure Node according to (optional) parameters:
            mac: MAC address for default interface
            ip: IP address for default interface
@@ -440,7 +428,7 @@ class Node( object ):
            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 = Parent.config( **_params )
         r = {}
         self.setParam( r, 'setMAC', mac=mac )
         self.setParam( r, 'setIP', ip=ip )
@@ -473,6 +461,24 @@ class Node( object ):
         return '%s: IP=%s intfs=%s pid=%s' % (
             self.name, self.IP(), ','.join( self.intfNames() ), self.pid )
 
+    # 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"
@@ -484,7 +490,7 @@ class CPULimitedHost( Host ):
     "CPU limited host"
 
     def __init__( self, *args, **kwargs ):
-        Node.__init__( self, *args, **kwargs )
+        Host.__init__( self, *args, **kwargs )
         # Create a cgroup and move shell into it
         self.cgroup = 'cpu,cpuacct:/' + self.name
         errFail( 'cgcreate -g ' + self.cgroup )
@@ -510,6 +516,7 @@ class CPULimitedHost( Host ):
         return nvalue
 
     def cgroupGet( self, param, resource='cpu' ):
+        "Return value of cgroup parameter"
         cmd = 'cgget -r %s.%s /%s' % (
             resource, param, self.name )
         return quietRun( cmd ).split()[ -1 ]
@@ -544,7 +551,7 @@ class CPULimitedHost( Host ):
         return pstr, qstr, period, quota
 
     # BL comment:
-    # This may not be the right API, 
+    # 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.
@@ -578,7 +585,7 @@ class CPULimitedHost( Host ):
             self.chrt( prio=20 )
         info( '(%s %d/%dus) ' % ( sched, quota, period ) )
 
-    def config( self, cpu=None, sched=None, **params ):
+    def config( self, cpu=None, **params ):
         """cpu: desired overall system CPU fraction
            params: parameters for Node.config()"""
         r = Node.config( self, **params )
@@ -665,8 +672,8 @@ class UserSwitch( Switch ):
         pathCheck( 'ofdatapath', 'ofprotocol',
             moduleName='the OpenFlow reference user switch (openflow.org)' )
 
-    @staticmethod
-    def setup():
+    @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 )
@@ -684,7 +691,7 @@ class UserSwitch( Switch ):
         if self.inNamespace:
             intfs = intfs[ :-1 ]
         self.cmd( 'ofdatapath -i ' + ','.join( intfs ) +
-            ' punix:/tmp/' + self.name + ' -d ' + self.dpid + 
+            ' punix:/tmp/' + self.name + ' -d ' + self.dpid +
             ' --no-slicing ' +
             ' 1> ' + ofdlog + ' 2> ' + ofdlog + ' &' )
         self.cmd( 'ofprotocol unix:/tmp/' + self.name +
@@ -716,8 +723,8 @@ class OVSLegacyKernelSwitch( Switch ):
                 " in the root namespace.\n" )
             exit( 1 )
 
-    @staticmethod
-    def setup():
+    @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)')
@@ -741,7 +748,7 @@ class OVSLegacyKernelSwitch( Switch ):
         controller = controllers[ 0 ]
         self.cmd( 'ovs-openflowd ' + self.dp +
             ' tcp:%s:%d' % ( controller.IP(), controller.port ) +
-            ' --fail=secure ' + self.opts + 
+            ' --fail=secure ' + self.opts +
             ' --datapath-id=' + self.dpid +
             ' 1>' + ofplog + ' 2>' + ofplog + '&' )
         self.execed = False
@@ -766,26 +773,34 @@ class OVSSwitch( Switch ):
         # dpid, which is a 64-bit numerical value used by
         # the openflow protocol.
         self.dp = name
-        
-    @staticmethod
-    def setup():
+        if self.inNamespace:
+            error( "OVSSwitch currently only works"
+                " in the root namespace.\n" )
+            exit( 1 )
+
+    @classmethod
+    def setup( cls ):
         "Make sure Open vSwitch is installed and working"
-        pathCheck( 'ovs-vsctl', 
+        pathCheck( 'ovs-vsctl',
             moduleName='Open vSwitch (openvswitch.org)')
         moduleDeps( subtract=OF_KMOD, add=OVS_KMOD )
         out, err, exitcode = errRun( 'ovs-vsctl -t 1 show' )
         if exitcode:
-            error( out + err + 
+            error( out + err +
                    'ovs-vsctl exited with code %d\n' % exitcode +
                    '*** Error connecting to ovs-db with ovs-vsctl\n'
                    'Make sure that Open vSwitch is installed, '
                    'that ovsdb-server is running, and that\n'
                    '"ovs-vsctl show" works correctly.\n'
-                   'You may wish to try "service openvswitch-switch start".\n' )
+                   'You may wish to try '
+                   '"service openvswitch-switch start".\n' )
             exit( 1 )
 
     def start( self, controllers ):
         "Start up a new OVS OpenFlow switch using ovs-vsctl"
+        if self.inNamespace:
+            raise Exception( 
+                'OVS kernel switch does not work in a namespace' )
         # Annoyingly, --if-exists option seems not to work
         self.cmd( 'ovs-vsctl del-br ', self.dp )
         self.cmd( 'ovs-vsctl add-br', self.dp )
@@ -800,7 +815,8 @@ class OVSSwitch( Switch ):
             self.cmd( 'ovs-vsctl add-port', self.dp, intf )
             self.cmd( 'ifconfig', intf, 'up' )
         # Add controllers
-        clist = ','.join( [ 'tcp:%s:%d' % ( c.IP(), c.port ) for c in controllers ] )
+        clist = ','.join( [ 'tcp:%s:%d' % ( c.IP(), c.port )
+                            for c in controllers ] )
         self.cmd( 'ovs-vsctl set-controller', self.dp, clist )
 
     def stop( self ):

mininet/topo.py

@@ -16,7 +16,7 @@ setup for testing, and can even be emulated with the Mininet package.
 # from networkx.classes.graph import Graph
 
 from networkx import Graph
-from util import netParse, ipStr
+from mininet.util import netParse, ipStr
 
 class NodeID(object):
     '''Topo node identifier.'''
@@ -116,7 +116,7 @@ class Topo(object):
        per-node/link classes and parameters
        per-topo classes
        per-network classes"""
-    
+
     def __init__(self, node=None, switch=None, link=None ):
         """Create Topo object.
            node: default node/host class (optional)
@@ -364,7 +364,7 @@ class Topo(object):
         # BL: may wish to rethink this or just use dicts..
         return self.node_info[ dpid ]
 
-    
+
 class SingleSwitchTopo(Topo):
     '''Single switch connected to k hosts.'''
 

mininet/util.py

@@ -47,10 +47,11 @@ def oldQuietRun( *cmd ):
             break
     return out
 
+
 # This is a bit complicated, but it enables us to
 # monitor commount output as it is happening
 
-def errRun( *cmd, **kwargs  ):
+def errRun( *cmd, **kwargs ):
     """Run a command and return stdout, stderr and return code
        cmd: string or list of command and args
        stderr: STDOUT to merge stderr with stdout
@@ -80,7 +81,10 @@ def errRun( *cmd, **kwargs  ):
         poller.register( popen.stderr, POLLIN )
     while True:
         readable = poller.poll()
+        # Tell pylint to ignore unused variable event
+        # pylint: disable-msg=W0612
         for fd, event in readable:
+            # pylint: enable-msg=W0612
             f = fdtofile[ fd ]
             data = f.read( 1024 )
             if echo:
@@ -91,7 +95,7 @@ def errRun( *cmd, **kwargs  ):
                 err += data
         returncode = popen.poll()
         if returncode is not None:
-           break
+            break
     return out, err, returncode
 
 def errFail( *cmd, **kwargs ):
@@ -186,13 +190,13 @@ def moveIntf( intf, node, printError=False, retries=3, delaySecs=0.001 ):
 
 # IP and Mac address formatting and parsing
 
-def _colonHex( val, bytes ):
+def _colonHex( val, bytecount ):
     """Generate colon-hex string.
        val: input as unsigned int
-       bytes: number of bytes to convert
+       bytescount: number of bytes to convert
        returns: chStr colon-hex string"""
     pieces = []
-    for i in range( bytes - 1, -1, -1 ):
+    for i in range( bytecount - 1, -1, -1 ):
         piece = ( ( 0xff << ( i * 8 ) ) & val ) >> ( i * 8 )
         pieces.append( '%02x' % piece )
     chStr = ':'.join( pieces )
@@ -204,14 +208,14 @@ def macColonHex( mac ):
        returns: macStr MAC colon-hex string"""
     return _colonHex( mac, 6 )
 
-def ipStr( ip, defaultNet=10 ):
+def ipStr( ip ):
     """Generate IP address string from an unsigned int.
        ip: unsigned int of form w << 24 | x << 16 | y << 8 | z
        returns: ip address string w.x.y.z, or 10.x.y.z if w==0"""
     w = ( ip >> 24 ) & 0xff
     w = 10 if w == 0 else w
-    x = ( ip  >> 16 ) & 0xff
-    y = ( ip  >> 8 ) & 0xff
+    x = ( ip >> 16 ) & 0xff
+    y = ( ip >> 8 ) & 0xff
     z = ip & 0xff
     return "%i.%i.%i.%i" % ( w, x, y, z )
 
@@ -270,6 +274,7 @@ def fixLimits():
 def natural( text ):
     "To sort sanely/alphabetically: sorted( l, key=natural )"
     def num( s ):
+        "Convert text segment to int if necessary"
         return int( s ) if s.isdigit() else text
     return [  num( s ) for s in re.split( r'(\d+)', text ) ]
 
@@ -286,8 +291,7 @@ def numCores():
 def custom( cls, **params ):
     "Returns customized constructor for class cls."
     def customized( *args, **kwargs):
+        "Customized constructor"
         kwargs.update( params )
         return cls( *args, **kwargs )
     return customized
-
-