"""
vlanhost.py: Host subclass that uses a VLAN tag for the default interface.

Dependencies:
    This class depends on the "vlan" package
    $ sudo apt-get install vlan

Usage (example uses VLAN ID=1000):
    From the command line:
        sudo mn --custom vlanhost.py --host vlan,vlan=1000

    From a script (see exampleUsage function below):
        from functools import partial
        from vlanhost import VLANHost

        ....

        host = partial( VLANHost, vlan=1000 )
        net = Mininet( host=host, ... )

    Directly running this script:
        sudo python vlanhost.py 1000

"""

from mininet.node import Host

class VLANHost( Host ):

   def config( self, vlan=100, **params ):
        """Configure VLANHost according to (optional) parameters:
           vlan: VLAN ID for default interface"""

        r = super( Host, self ).config( **params )

        intf = self.defaultIntf()
        # remove IP from default, "physical" interface
        self.cmd( 'ifconfig %s inet 0' % intf )
        # create VLAN interface 
        self.cmd( 'vconfig add %s %d' % ( intf, vlan ) )
        # assign the host's IP to the VLAN interface
        self.cmd( 'ifconfig %s.%d inet %s' % ( intf, vlan, params['ip'] ) )
        # update the intf name and host's intf map
        newName = '%s.%d' % ( intf, vlan )
        # update the (Mininet) interface to refer to VLAN interface name
        intf.name = newName
        # add VLAN interface to host's name to intf map
        self.nameToIntf[ newName ] = intf

        return r

hosts = { 'vlan': VLANHost }


def exampleUsage( vlan ):
    """Simple example of how VLANHost can be used in a script"""
    # This is where the magic happens...
    host = partial( VLANHost, vlan=vlan )
    # vlan (type: int): VLAN ID to be used by all hosts

    # Start a basic network using our VLANHost
    topo = SingleSwitchTopo( k=2 )
    net = Mininet( host=host, topo=topo )
    net.start()
    CLI( net )
    net.stop()

if __name__ == '__main__':
    import sys
    from functools import partial

    from mininet.net import Mininet
    from mininet.cli import CLI
    from mininet.topo import SingleSwitchTopo

    try:
        vlan = int( sys.argv[ 1 ] )
    except Exception:
        print 'Usage: vlanhost.py <vlan id>\n'
        print 'Using VLAN ID=100...'
        vlan = 100

    exampleUsage( vlan )