#!/usr/bin/python

"""
Simple example of setting network and CPU parameters

NOTE: link params limit BW, add latency, and loss.
There is a high chance that pings WILL fail and that
iperf will hang indefinitely if the TCP handshake fails
to complete.
"""

from src.mininet.topo import Topo
from src.mininet.net import Mininet
from src.mininet.node import CPULimitedHost
from src.mininet.link import TCLink
from src.mininet.util import dumpNodeConnections
from src.mininet.log import setLogLevel

from sys import argv

class SingleSwitchTopo(Topo):
    "Single switch connected to n hosts."
    def __init__(self, n=2, lossy=True, **opts):
        Topo.__init__(self, **opts)
        switch = self.addSwitch('s1')
        for h in range(n):
            # Each host gets 50%/n of system CPU
            host = self.addHost('h%s' % (h + 1),
                                cpu=.5 / n)
            if lossy:
                # 10 Mbps, 5ms delay, 10% packet loss
                self.addLink(host, switch,
                             bw=10, delay='5ms', loss=10, use_htb=True)
            else:
                # 10 Mbps, 5ms delay, no packet loss
                self.addLink(host, switch,
                             bw=10, delay='5ms', loss=0, use_htb=True)


def perfTest( lossy=True ):
    "Create network and run simple performance test"
    topo = SingleSwitchTopo( n=4, lossy=lossy )
    net = Mininet( topo=topo,
                   host=CPULimitedHost, link=TCLink,
                   autoStaticArp=True )
    net.start()
    print "Dumping host connections"
    dumpNodeConnections(net.hosts)
    print "Testing bandwidth between h1 and h4"
    h1, h4 = net.getNodeByName('h1', 'h4')
    net.iperf( ( h1, h4 ), l4Type='UDP' )
    net.stop()

if __name__ == '__main__':
    setLogLevel( 'info' )
    # Prevent test_simpleperf from failing due to packet loss
    perfTest( lossy=( 'testmode' not in argv ) )
