MPTCP test environment

mptcp-test.py

#!/usr/bin/python
import sys
from time import sleep
from math import sqrt 
import argparse
from subprocess import Popen, PIPE
from mininet.net import Mininet
from mininet.link import TCLink
from mininet.topo import Topo
from mininet.log import lg


"""
bandwidth: Mbps
delay: ms, 1-way
loss rate: 0-100
queue size: # packets
"""
links = [
		[10, 20, 0, 1000000],
		[10, 20, 0, 1000000]
]

class TwoHostNLink(Topo):
	def __init__(self, **opts):
		super(TwoHostNLink, self).__init__(**opts)

		# add switches
		switches = []
		for i in range(len(links)):
			switches.append('s%i' % (i+1))
			self.addSwitch('s%i' % (i+1))

		# add hosts
		self.addHost('h1')
		self.addHost('h2')
		
		# add links
		for i in range(len(links)):
			bw = links[i][0]
			delay = links[i][1]/2
			loss = (100-sqrt(100-links[i][2]))/100
			qsize = links[i][3]
			self.addLink('h1', switches[i], bw=bw, delay=str(delay)+'ms', loss=loss, max_queue_size=qsize)
			self.addLink('h2', switches[i], bw=bw, delay=str(delay)+'ms', loss=loss, max_queue_size=qsize)

def progress(t):
	while t > 0:
		print "%3d seconds left" % t
		t -= 1
		sleep(1)
	print "\n"

def parse_args():
	parser = argparse.ArgumentParser(description="MPTCP 2-host n-switch test")
	parser.add_argument('--mptcp',
		action="store_true",
		help="Enable MPTCP (net.mptcp.mptcp_enabled)",
		default=False)
	parser.add_argument('--ndiffports',
		action="store",
		help="Set # subflows (net.mptcp.mptcp_ndiffports)",
		default=1)
	parser.add_argument('-t',
		action="store",
		help="Seconds to run the experiment",
		default=2)
	args = parser.parse_args()
	args.ndiffports = int(args.ndiffports)
	return args

def sysctl_set(key, value):
	"""Issue systcl for given param to given value and check for error."""
	p = Popen("sysctl -w %s=%s" % (key, value), shell=True, stdout=PIPE,
						stderr=PIPE)
	# Output should be empty; otherwise, we have an issue.	
	stdout, stderr = p.communicate()
	stdout_expected = "%s = %s\n" % (key, value)
	if stdout != stdout_expected:
		raise Exception("Popen returned unexpected stdout: %s != %s" % (stdout, stdout_expected))
	if stderr:
		raise Exception("Popen returned unexpected stderr: %s" % stderr)

def set_mptcp_enabled(enabled):
	"""Enable MPTCP if true, disable if false"""
	e = 1 if enabled else 0
	lg.info("setting MPTCP enabled to %s\n" % e)
	sysctl_set('net.mptcp.mptcp_enabled', e)

def set_mptcp_ndiffports(ports):
	"""Set ndiffports, the number of subflows to instantiate"""
	lg.info("setting MPTCP ndiffports to %s\n" % ports)
	sysctl_set("net.mptcp.mptcp_ndiffports", ports)

def setup(args):
	set_mptcp_enabled(args.mptcp)
	set_mptcp_ndiffports(args.ndiffports)

def end(args):
	set_mptcp_enabled(False)
	set_mptcp_ndiffports(1)

def run(args, net):
	seconds = int(args.t)
	h1 = net.getNodeByName('h1')
	h2 = net.getNodeByName('h2')

	for i in range(len(links)):
		# Setup IPs:
		h1.cmdPrint('ifconfig h1-eth%i 10.0.%i.3 netmask 255.255.255.0' % (i, i))
		h2.cmdPrint('ifconfig h2-eth%i 10.0.%i.4 netmask 255.255.255.0' % (i, i))

		if args.mptcp:
			lg.info("configuring source-specific routing tables for MPTCP\n")
			# This creates two different routing tables, that we use based on the
			# source-address.
			dev = 'h1-eth%i' % i
			table = '%s' % (i + 1)
			h1.cmdPrint('ip rule add from 10.0.%i.3 table %s' % (i, table))
			h1.cmdPrint('ip route add 10.0.%i.0/24 dev %s scope link table %s' % (i, dev, table))
			h1.cmdPrint('ip route add default via 10.0.%i.1 dev %s table %s' % (i, dev, table))

	# TODO: expand this to verify connectivity with a ping test.
	lg.info("pinging each destination interface\n")
	for i in range(len(links)):
		h2_out = h2.cmd('ping -c 1 10.0.%i.3' % i)
		lg.info("ping test output: %s\n" % h2_out)

	lg.info("iperfing\n")
	h2.sendCmd('iperf -s -i 1')

	cmd = 'iperf -c 10.0.0.4 -t %d -i 1' % seconds
	h1.sendCmd(cmd)
	progress(seconds + 1)
	h1_out = h1.waitOutput()
	lg.info("client output:\n%s\n" % h1_out)
	sleep(0.1)	# hack to wait for iperf server output.
	out = h2.read(10000)
	lg.info("server output: %s\n" % out)
	return None

def genericTest(args, topo, setup, run, end):
	net = Mininet(topo=topo, link=TCLink)
	setup(args)
	net.start()
	data = run(args, net)
	net.stop()
	end(args)
	return data

def main():
	args = parse_args()
	lg.setLogLevel('info')
	topo = TwoHostNLink()
	genericTest(args, topo, setup, run, end)

if __name__ == '__main__':
	main()

Hello,
I wanted to run the above code in Ubuntu 14.04 , running MPTCP kernel and mininet ver 2.2.1. It gives following error, can you help in this regard:

File "mptcp-test.py", line 90, in set_mptcp_enabled
sysctl_set('net.mptcp.mptcp_enabled', e)
File "mptcp-test.py", line 82, in sysctl_set
raise Exception("Popen returned unexpected stdout: %s != %s" % (stdout, stdout_expected))
Exception: Popen returned unexpected stdout: != net.mptcp.mptcp_enabled = 0

Hello, I get an assertion error on net.stop(). Do you know how can I solve it?