click.py

"""
Wrapper for Click software routers for the Mininet network virtualizer
"""

import fileinput, shutil, os
from mininet.node import Switch
from mininet.util import quietRun
from mininet.moduledeps import moduleDeps, pathCheck


class ClickKernelSwitch( Switch ):
    """Click kernel-space switch, based on OVSKernelSwitch."""

    def __init__( self, name, configPath=None, dp=None, **kwargs ):
        """Init.
           name: name for switch
           dp: netlink id (0, 1, 2, ...)
           defaultMAC: default MAC as unsigned int; random value if None"""
        Switch.__init__( self, name, **kwargs )
        self.dp = 'dp%i' % dp
        self.intf = self.dp
        # Create a copy of the config for renaming
        if not configPath:
            configPath = os.path.join(os.getcwd(), "test.click")
        self.configPath = configPath + ".intf"
        shutil.copy(configPath, self.configPath)

    @staticmethod
    def setup():
        "Ensure any dependencies are loaded; if not, try to load them."
        pathCheck( 'click-install', 'click-uninstall',
            moduleName='Click Kernel Switch')

    def intfRename(self, intf, intfName):
        """
        Rename interfaces in the Click config file with those generated by
        Mininet.
        """
        for line in fileinput.input(self.configPath, inplace=True):
            print line.replace(intfName, intf)

    def linkAs(self, node2, intfName, port1=None, port2=None):
        """
        Link the given node to the switch on the given interface in the Click
        config file.
        """
        intf1, intf2 = super(ClickKernelSwitch, self).linkTo(node2, port1, port2)
        self.intfRename(intf1, intfName)
        quietRun('ifconfig ' + intf1 + ' up')
        return intf1, intf2

    def start( self, controllers ):
        """
        Install the Click kernel module with the proper configuration.
        """
        self.cmd("click-install " + self.configPath)
        quietRun('ifconfig lo up')

    def stop( self ):
        """
        Remove the Click kernel module and remove the generated config file.
        """
        self.cmd("click-uninstall")
        os.remove(self.configPath)