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#!/usr/bin/env python
"""
multiping.py: monitor multiple sets of hosts using ping
This demonstrates how one may send a simple shell script to
multiple hosts and monitor their output interactively for a period=
of time.
"""
from select import poll, POLLIN
from time import time
from mininet.net import Mininet
from mininet.node import Node
from mininet.topo import SingleSwitchTopo
from mininet.log import info, setLogLevel
def chunks( l, n ):
"Divide list l into chunks of size n - thanks Stackoverflow"
return [ l[ i: i + n ] for i in range( 0, len( l ), n ) ]
def startpings( host, targetips ):
"Tell host to repeatedly ping targets"
targetips = ' '.join( targetips )
# Simple ping loop
cmd = ( 'while true; do '
' for ip in %s; do ' % targetips +
' echo -n %s "->" $ip ' % host.IP() +
' `ping -c1 -w 1 $ip | grep packets` ;'
' sleep 1;'
' done; '
'done &' )
info( '*** Host %s (%s) will be pinging ips: %s\n' %
( host.name, host.IP(), targetips ) )
host.cmd( cmd )
def multiping( netsize, chunksize, seconds):
"Ping subsets of size chunksize in net of size netsize"
# Create network and identify subnets
topo = SingleSwitchTopo( netsize )
net = Mininet( topo=topo, waitConnected=True )
net.start()
hosts = net.hosts
subnets = chunks( hosts, chunksize )
# Create polling object
fds = [ host.stdout.fileno() for host in hosts ]
poller = poll()
for fd in fds:
poller.register( fd, POLLIN )
# Start pings
for subnet in subnets:
ips = [ host.IP() for host in subnet ]
# adding bogus to generate packet loss
ips.append( '10.0.0.200' )
for host in subnet:
startpings( host, ips )
# Monitor output
endTime = time() + seconds
while time() < endTime:
readable = poller.poll(1000)
for fd, _mask in readable:
node = Node.outToNode[ fd ]
info( '%s:' % node.name, node.monitor().strip(), '\n' )
# Stop pings
for host in hosts:
host.cmd( 'kill %while' )
net.stop()
if __name__ == '__main__':
setLogLevel( 'info' )
multiping( netsize=20, chunksize=4, seconds=10 )
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