Revision 89bf3103 mininet/net.py

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mininet/net.py
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from resource import setrlimit, RLIMIT_NPROC, RLIMIT_NOFILE
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from mininet.logging_mod import lg, set_loglevel
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from mininet.node import Node, Host, Controller, Switch
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from mininet.util import run, checkRun, quietRun, makeIntfPair, moveIntf
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from mininet.util import createLink
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DATAPATHS = ['user', 'kernel']
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class Node( object ):
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   """A virtual network node is simply a shell in a network namespace.
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      We communicate with it using pipes."""
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   inToNode = {}
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   outToNode = {}
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   def __init__( self, name, inNamespace=True ):
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      self.name = name
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      closeFds = False # speed vs. memory use
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      # xpg_echo is needed so we can echo our sentinel in sendCmd
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      cmd = [ '/bin/bash', '-O', 'xpg_echo' ]
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      self.inNamespace = inNamespace
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      if self.inNamespace: cmd = [ 'netns' ] + cmd
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      self.shell = Popen( cmd, stdin=PIPE, stdout=PIPE, stderr=STDOUT,
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         close_fds=closeFds )
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      self.stdin = self.shell.stdin
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      self.stdout = self.shell.stdout
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      self.pollOut = select.poll() 
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      self.pollOut.register( self.stdout )
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      # Maintain mapping between file descriptors and nodes
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      # This could be useful for monitoring multiple nodes
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      # using select.poll()
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      self.outToNode[ self.stdout.fileno() ] = self
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      self.inToNode[ self.stdin.fileno() ] = self
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      self.pid = self.shell.pid
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      self.intfCount = 0
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      self.intfs = [] # list of interface names, as strings
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      self.ips = {}
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      self.connection = {}
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      self.waiting = False
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      self.execed = False
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   def fdToNode( self, f ):
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      node = self.outToNode.get( f )
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      return node or self.inToNode.get( f )
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   def cleanup( self ):
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      # Help python collect its garbage
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      self.shell = None
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   # Subshell I/O, commands and control
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   def read( self, max ): return os.read( self.stdout.fileno(), max )
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   def write( self, data ): os.write( self.stdin.fileno(), data )
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   def terminate( self ):
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      os.kill( self.pid, signal.SIGKILL )
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      self.cleanup()
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   def stop( self ): self.terminate()
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   def waitReadable( self ): self.pollOut.poll()
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   def sendCmd( self, cmd ):
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      """Send a command, followed by a command to echo a sentinel,
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         and return without waiting for the command to complete."""
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      assert not self.waiting
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      if cmd[ -1 ] == '&':
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         separator = '&'
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         cmd = cmd[ : -1 ]
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      else: separator = ';'
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      if isinstance( cmd, list): cmd = ' '.join( cmd )
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      self.write( cmd + separator + " echo -n '\\0177' \n")
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      self.waiting = True
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   def monitor( self ):
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      "Monitor a command's output, returning (done, data)."
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      assert self.waiting
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      self.waitReadable()
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      data = self.read( 1024 )
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      if len( data ) > 0 and data[ -1 ] == chr( 0177 ):
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         self.waiting = False
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         return True, data[ : -1 ]
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      else:
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         return False, data
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   def sendInt( self ):
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      "Send ^C, hopefully interrupting a running subprocess."
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      self.write( chr( 3 ) )
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   def waitOutput( self ):
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      """Wait for a command to complete (signaled by a sentinel
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      character, ASCII(127) appearing in the output stream) and return
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      the output, including trailing newline."""
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      assert self.waiting
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      output = ""
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      while True:
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         self.waitReadable()
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         data = self.read( 1024 )
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         if len(data) > 0  and data[ -1 ] == chr( 0177 ): 
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            output += data[ : -1 ]
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            break
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         else: output += data
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      self.waiting = False
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      return output
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   def cmd( self, cmd ):
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      "Send a command, wait for output, and return it."
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      self.sendCmd( cmd )
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      return self.waitOutput()
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   def cmdPrint( self, cmd ):
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      "Call cmd, printing the command and output"
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      #lg.info("*** %s : %s", self.name, cmd)
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      result = self.cmd( cmd )
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      #lg.info("%s\n", result)
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      return result
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   # Interface management, configuration, and routing
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   def intfName( self, n):
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      "Construct a canonical interface name node-intf for interface N."
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      return self.name + '-eth' + `n`
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   def newIntf( self ):
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      "Reserve and return a new interface name for this node."
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      intfName = self.intfName( self.intfCount)
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      self.intfCount += 1
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      self.intfs += [ intfName ]
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      return intfName
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   def setIP( self, intf, ip, bits ):
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      "Set an interface's IP address."
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      result = self.cmd( [ 'ifconfig', intf, ip + bits, 'up' ] )
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      self.ips[ intf ] = ip
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      return result
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   def setHostRoute( self, ip, intf ):
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      "Add a route to the given IP address via intf."
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      return self.cmd( 'route add -host ' + ip + ' dev ' + intf )
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   def setDefaultRoute( self, intf ):
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      "Set the default route to go through intf."
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      self.cmd( 'ip route flush' )
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      return self.cmd( 'route add default ' + intf )
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   def IP( self ):
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      "Return IP address of first interface"
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      if len( self.intfs ) > 0:
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         return self.ips.get( self.intfs[ 0 ], None )
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   def intfIsUp( self, intf ):
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      "Check if one of our interfaces is up."
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      return 'UP' in self.cmd( 'ifconfig ' + self.intfs[ 0 ] )
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   # Other methods  
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   def __str__( self ): 
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      result = self.name + ":"
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      if self.IP():
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          result += " IP=" + self.IP()
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      result += " intfs=" + ','.join( self.intfs )
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      result += " waiting=" +  `self.waiting`
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      return result
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class Host( Node ):
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   """A host is simply a Node."""
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   pass
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class Controller( Node ):
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   """A Controller is a Node that is running (or has execed) an 
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      OpenFlow controller."""
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   def __init__( self, name, kernel=True, controller='controller',
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      cargs='-v ptcp:', cdir=None ):
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      self.controller = controller
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      self.cargs = cargs
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      self.cdir = cdir
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      Node.__init__( self, name, inNamespace=( not kernel ) )
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   def start( self ):
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      "Start <controller> <args> on controller, logging to /tmp/cN.log"
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      cout = '/tmp/' + self.name + '.log'
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      if self.cdir is not None:
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         self.cmdPrint( 'cd ' + self.cdir )
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      self.cmdPrint( self.controller + ' ' + self.cargs + 
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         ' 1> ' + cout + ' 2> ' + cout + ' &' )
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      self.execed = False # XXX Until I fix it
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   def stop( self, controller='controller' ):
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      "Stop controller cprog on controller"
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      self.cmd( "kill %" + controller )  
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      self.terminate()
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class Switch( Node ):
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   """A Switch is a Node that is running (or has execed)
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      an OpenFlow switch."""
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   def __init__( self, name, datapath=None ):
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      self.dp = datapath
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      Node.__init__( self, name, inNamespace=( datapath == None ) )
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   def startUserDatapath( self, controller ):
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      """Start OpenFlow reference user datapath, 
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         logging to /tmp/sN-{ofd,ofp}.log"""
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      ofdlog = '/tmp/' + self.name + '-ofd.log'
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      ofplog = '/tmp/' + self.name + '-ofp.log'
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      self.cmd( 'ifconfig lo up' )
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      intfs = self.intfs[ 1 : ] # 0 is mgmt interface
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      self.cmdPrint( 'ofdatapath -i ' + ','.join( intfs ) +
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       ' ptcp: 1> ' + ofdlog + ' 2> '+ ofdlog + ' &' )
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      self.cmdPrint( 'ofprotocol tcp:' + controller.IP() +
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         ' tcp:localhost --fail=closed 1> ' + ofplog + ' 2>' + ofplog + ' &' )
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   def stopUserDatapath( self ):
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      "Stop OpenFlow reference user datapath."
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      self.cmd( "kill %ofdatapath" )
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      self.cmd( "kill %ofprotocol" )
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   def startKernelDatapath( self, controller):
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      "Start up switch using OpenFlow reference kernel datapath."
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      ofplog = '/tmp/' + self.name + '-ofp.log'
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      quietRun( 'ifconfig lo up' )
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      # Delete local datapath if it exists;
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      # then create a new one monitoring the given interfaces
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      quietRun( 'dpctl deldp ' + self.dp )
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      self.cmdPrint( 'dpctl adddp ' + self.dp )
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      self.cmdPrint( 'dpctl addif ' + self.dp + ' ' + ' '.join( self.intfs ) )
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      # Run protocol daemon
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      self.cmdPrint( 'ofprotocol' +
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         ' ' + self.dp + ' tcp:127.0.0.1 ' + 
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         ' --fail=closed 1> ' + ofplog + ' 2>' + ofplog + ' &' )
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      self.execed = False # XXX until I fix it
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   def stopKernelDatapath( self ):
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      "Terminate a switch using OpenFlow reference kernel datapath."
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      quietRun( 'dpctl deldp ' + self.dp )
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      # In theory the interfaces should go away after we shut down.
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      # However, this takes time, so we're better off to remove them
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      # explicitly so that we won't get errors if we run before they
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      # have been removed by the kernel. Unfortunately this is very slow.
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      self.cmd( 'kill %ofprotocol')
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      for intf in self.intfs:
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         quietRun( 'ip link del ' + intf )
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         lg.info('.')
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   def start( self, controller ): 
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      if self.dp is None: self.startUserDatapath( controller )
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      else: self.startKernelDatapath( controller )
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   def stop( self ):
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      if self.dp is None: self.stopUserDatapath()
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      else: self.stopKernelDatapath()
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   def sendCmd( self, cmd ):
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      if not self.execed:
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          return Node.sendCmd( self, cmd )
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      else:
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          lg.error("*** Error: %s has execed and cannot accept commands" %
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                 self.name)
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   def monitor( self ):
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      if not self.execed: return Node.monitor( self )
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      else: return True, ''
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# Handy utilities
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def dumpNodes( nodes ):
......
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      switch.setHostRoute( cip, sintf )
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   lg.info("\n")
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   lg.info("*** Testing control network\n")
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   while not controller.intfIsUp( controller.intfs[ 0 ] ):
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   while not controller.intfIsUp():
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      lg.info("*** Waiting for %s to come up\n", controller.intfs[ 0 ])
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      sleep( 1 )
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   for switch in switches:
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      while not switch.intfIsUp( switch.intfs[ 0 ] ):
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      while not switch.intfIsUp():
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         lg.info("*** Waiting for %s to come up\n" % switch.intfs[ 0 ])
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         sleep( 1 )
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      if pingTest( hosts=[ switch, controller ] ) != 0:

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