#!/usr/bin/python

"""
Build a simple network from scratch, using mininet primitives.
This is more complicated than using the higher-level classes,
but it exposes the configuration details and allows customization.

For most tasks, the higher-level API will be preferable.
"""

from __future__ import print_function

from mininet.net import Mininet
from mininet.node import Node
from mininet.link import Link
from mininet.log import setLogLevel, info
from mininet.util import quietRun

from time import sleep

def scratchNet( cname='controller', cargs='-v ptcp:' ):
    "Create network from scratch using Open vSwitch."

    info( "*** Creating nodes\n" )
    controller = Node( 'c0', inNamespace=False )
    switch = Node( 's0', inNamespace=False )
    h0 = Node( 'h0' )
    h1 = Node( 'h1' )

    info( "*** Creating links\n" )
    Link( h0, switch )
    Link( h1, switch )

    info( "*** Configuring hosts\n" )
    h0.setIP( '192.168.123.1/24' )
    h1.setIP( '192.168.123.2/24' )
    info( str( h0 ) + '\n' )
    info( str( h1 ) + '\n' )

    info( "*** Starting network using Open vSwitch\n" )
    controller.cmd( cname + ' ' + cargs + '&' )
    switch.cmd( 'ovs-vsctl del-br dp0' )
    switch.cmd( 'ovs-vsctl add-br dp0' )
    for intf in switch.intfs.values():
        print( switch.cmd( 'ovs-vsctl add-port dp0 %s' % intf ) )

    # Note: controller and switch are in root namespace, and we
    # can connect via loopback interface
    switch.cmd( 'ovs-vsctl set-controller dp0 tcp:127.0.0.1:6633' )

    info( '*** Waiting for switch to connect to controller' )
    while 'is_connected' not in quietRun( 'ovs-vsctl show' ):
        sleep( 1 )
        info( '.' )
    info( '\n' )

    info( "*** Running test\n" )
    h0.cmdPrint( 'ping -c1 ' + h1.IP() )

    info( "*** Stopping network\n" )
    controller.cmd( 'kill %' + cname )
    switch.cmd( 'ovs-vsctl del-br dp0' )
    switch.deleteIntfs()
    info( '\n' )

if __name__ == '__main__':
    setLogLevel( 'info' )
    info( '*** Scratch network demo (kernel datapath)\n' )
    Mininet.init()
    scratchNet()