bce45ca8e6
* moved basic exercise to new run script * forgot some files * CLI output now goes to logs * typo, and forgot topo file * fixed net.stop() bug * added temporary change to makefile * typos hard
345 lines
14 KiB
Python
Executable File
345 lines
14 KiB
Python
Executable File
#!/usr/bin/env python2
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# Copyright 2013-present Barefoot Networks, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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# Adapted by Robert MacDavid (macdavid@cs.princeton.edu) from scripts found in
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# the p4app repository (https://github.com/p4lang/p4app)
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#
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# We encourage you to dissect this script to better understand the BMv2/Mininet
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# environment used by the P4 tutorial.
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#
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import os, sys, json, subprocess, re, argparse
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from time import sleep
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# this path is needed to import p4_mininet.py from the bmv2 repo
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sys.path.append('/home/vagrant/behavioral-model/mininet')
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from p4_mininet import P4Switch, P4Host
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from mininet.net import Mininet
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from mininet.topo import Topo
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from mininet.link import TCLink
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from mininet.cli import CLI
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first_thrift_port = 9090
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next_thrift_port = first_thrift_port
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def configureP4Switch(**switch_args):
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""" Helper class that is called by mininet to initialize
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the virtual P4 switches. The purpose is to ensure each
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switch's thrift server is using a unique port.
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"""
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class ConfiguredP4Switch(P4Switch):
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def __init__(self, *opts, **kwargs):
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global next_thrift_port
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kwargs.update(switch_args)
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kwargs['thrift_port'] = next_thrift_port
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next_thrift_port += 1
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P4Switch.__init__(self, *opts, **kwargs)
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return ConfiguredP4Switch
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class ExerciseTopo(Topo):
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""" The mininet topology class for the P4 tutorial exercises.
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A custom class is used because the exercises make a few topology
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assumptions, mostly about the IP and MAC addresses.
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"""
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def __init__(self, hosts, switches, links, log_dir, **opts):
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Topo.__init__(self, **opts)
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host_links = []
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switch_links = []
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for link in links:
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if link['node1'][0] == 'h':
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host_links.append(link)
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else:
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switch_links.append(link)
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link_sort_key = lambda x: x['node1'] + x['node2']
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# Links must be added in a sorted order so bmv2 port numbers are predictable
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host_links.sort(key=link_sort_key)
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switch_links.sort(key=link_sort_key)
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for sw in switches:
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self.addSwitch(sw, log_file="%s/%s.log" %(log_dir, sw))
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for link in host_links:
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host_name = link['node1']
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host_sw = link['node2']
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host_num = int(host_name[1:])
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sw_num = int(host_sw[1:])
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host_ip = "10.0.%d.%d" % (sw_num, host_num)
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host_mac = '00:00:00:00:%02x:%02x' % (sw_num, host_num)
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# Each host IP should be /24, so all exercise traffic will use the
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# default gateway (the switch) without sending ARP requests.
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self.addHost(host_name, ip=host_ip+'/24', mac=host_mac)
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self.addLink(host_name, host_sw,
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delay=link['latency'], bw=link['bandwidth'],
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addr1=host_mac, addr2=host_mac)
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for link in switch_links:
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self.addLink(link['node1'], link['node2'],
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delay=link['latency'], bw=link['bandwidth'])
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class ExerciseRunner:
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"""
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Attributes:
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log_dir : string // directory for mininet log files
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pcap_dir : string // directory for mininet switch pcap files
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quiet : bool // determines if we print logger messages
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hosts : list<string> // list of mininet host names
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switches : dict<string, dict> // mininet host names and their associated properties
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links : list<dict> // list of mininet link properties
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switch_json : string // json of the compiled p4 example
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bmv2_exe : string // name or path of the p4 switch binary
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topo : Topo object // The mininet topology instance
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net : Mininet object // The mininet instance
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"""
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def logger(self, *items):
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if not self.quiet:
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print(' '.join(items))
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def formatLatency(l):
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""" Helper method for parsing link latencies from the topology json. """
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if isinstance(latencies[l], (str, unicode)):
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return l
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else:
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return str(l) + "ms"
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def __init__(self, topo_file, log_dir, pcap_dir,
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switch_json, bmv2_exe='simple_switch', quiet=False):
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""" Initializes some attributes and reads the topology json. Does not
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actually run the exercise. Use run_exercise() for that.
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Arguments:
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topo_file : string // A json file which describes the exercise's
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mininet topology.
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log_dir : string // Path to a directory for storing exercise logs
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pcap_dir : string // Ditto, but for mininet switch pcap files
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switch_json : string // Path to a compiled p4 json for bmv2
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bmv2_exe : string // Path to the p4 behavioral binary
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quiet : bool // Enable/disable script debug messages
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"""
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self.quiet = quiet
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self.logger('Reading topology file.')
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with open(topo_file, 'r') as f:
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topo = json.load(f)
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self.hosts = topo['hosts']
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self.switches = topo['switches']
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self.links = self.parse_links(topo['links'])
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# Ensure all the needed directories exist and are directories
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for dir_name in [log_dir, pcap_dir]:
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if not os.path.isdir(dir_name):
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if os.path.exists(dir_name):
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raise Exception("'%s' exists and is not a directory!" % dir_name)
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os.mkdir(dir_name)
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self.log_dir = log_dir
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self.pcap_dir = pcap_dir
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self.switch_json = switch_json
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self.bmv2_exe = bmv2_exe
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def run_exercise(self):
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""" Sets up the mininet instance, programs the switches,
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and starts the mininet CLI. This is the main method to run after
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initializing the object.
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"""
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# Initialize mininet with the topology specified by the config
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self.create_network()
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self.net.start()
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sleep(1)
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# some programming that must happen after the net has started
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self.program_hosts()
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self.program_switches()
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# wait for that to finish. Not sure how to do this better
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sleep(1)
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self.do_net_cli()
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# stop right after the CLI is exited
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self.net.stop()
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def parse_links(self, unparsed_links):
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""" Given a list of links descriptions of the form [node1, node2, latency, bandwidth]
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with the latency and bandwidth being optional, parses these descriptions
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into dictionaries and store them as self.links
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"""
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links = []
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for link in unparsed_links:
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# make sure each link's endpoints are ordered alphabetically
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s, t, = link[0], link[1]
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if s > t:
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s,t = t,s
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link_dict = {'node1':s,
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'node2':t,
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'latency':'0ms',
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'bandwidth':None
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}
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if len(link) > 2:
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link_dict['latency'] = self.formatLatency(link[2])
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if len(link) > 3:
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link_dict['bandwidth'] = link[3]
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if link_dict['node1'][0] == 'h':
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assert link_dict['node2'][0] == 's', 'Hosts should be connected to switches, not ' + str(link_dict['node2'])
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links.append(link_dict)
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return links
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def create_network(self):
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""" Create the mininet network object, and store it as self.net.
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Side effects:
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- Mininet topology instance stored as self.topo
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- Mininet instance stored as self.net
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"""
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self.logger("Building mininet topology.")
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self.topo = ExerciseTopo(self.hosts, self.switches.keys(), self.links, self.log_dir)
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switchClass = configureP4Switch(
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sw_path=self.bmv2_exe,
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json_path=self.switch_json,
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log_console=True,
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pcap_dump=self.pcap_dir)
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self.net = Mininet(topo = self.topo,
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link = TCLink,
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host = P4Host,
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switch = switchClass,
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controller = None)
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def program_switches(self):
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""" If any command files were provided for the switches,
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this method will start up the CLI on each switch and use the
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contents of the command files as input.
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Assumes:
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- A mininet instance is stored as self.net and self.net.start() has
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been called.
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"""
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cli = 'simple_switch_CLI'
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for sw_name, sw_dict in self.switches.iteritems():
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if 'cli_input' not in sw_dict: continue
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# get the port for this particular switch's thrift server
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sw_obj = self.net.get(sw_name)
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thrift_port = sw_obj.thrift_port
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cli_input_commands = sw_dict['cli_input']
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self.logger('Configuring switch %s with file %s' % (sw_name, cli_input_commands))
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with open(cli_input_commands, 'r') as fin:
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cli_outfile = '%s/%s_cli_output.log'%(self.log_dir, sw_name)
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with open(cli_outfile, 'w') as fout:
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subprocess.Popen([cli, '--thrift-port', str(thrift_port)],
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stdin=fin, stdout=fout)
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def program_hosts(self):
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""" Adds static ARP entries and default routes to each mininet host.
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Assumes:
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- A mininet instance is stored as self.net and self.net.start() has
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been called.
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"""
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for host_name in self.topo.hosts():
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h = self.net.get(host_name)
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h_iface = h.intfs.values()[0]
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link = h_iface.link
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sw_iface = link.intf1 if link.intf1 != h_iface else link.intf2
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# phony IP to lie to the host about
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host_id = int(host_name[1:])
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sw_ip = '10.0.%d.254' % host_id
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# Ensure each host's interface name is unique, or else
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# mininet cannot shutdown gracefully
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h.defaultIntf().rename('%s-eth0' % host_name)
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# static arp entries and default routes
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h.cmd('arp -i %s -s %s %s' % (h_iface.name, sw_ip, sw_iface.mac))
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h.cmd('ethtool --offload %s rx off tx off' % h_iface.name)
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h.cmd('ip route add %s dev %s' % (sw_ip, h_iface.name))
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h.setDefaultRoute("via %s" % sw_ip)
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def do_net_cli(self):
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""" Starts up the mininet CLI and prints some helpful output.
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Assumes:
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- A mininet instance is stored as self.net and self.net.start() has
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been called.
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"""
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self.logger("Starting mininet CLI")
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for h in self.net.hosts:
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h.describe()
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# Generate a message that will be printed by the Mininet CLI to make
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# interacting with the simple switch a little easier.
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print('')
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print('======================================================================')
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print('Welcome to the BMV2 Mininet CLI!')
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print('======================================================================')
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print('Your P4 program is installed into the BMV2 software switch')
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print('and your initial configuration is loaded. You can interact')
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print('with the network using the mininet CLI below.')
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print('')
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print('To inspect or change the switch configuration, connect to')
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print('its CLI from your host operating system using this command:')
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print(' simple_switch_CLI --thrift-port <switch thrift port>')
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print('')
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print('To view a switch log, run this command from your host OS:')
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print(' tail -f %s/<switchname>.log' % self.log_dir)
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print('')
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print('To view the switch output pcap, check the pcap files in %s:' % self.pcap_dir)
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print(' for example run: sudo tcpdump -xxx -r s1-eth1.pcap')
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print('')
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CLI(self.net)
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def get_args():
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cwd = os.getcwd()
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default_logs = os.path.join(cwd, 'logs')
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default_pcaps = os.path.join(cwd, 'pcaps')
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parser = argparse.ArgumentParser()
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parser.add_argument('-q', '--quiet', help='Suppress log messages.',
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action='store_true', required=False, default=False)
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parser.add_argument('-t', '--topo', help='Path to topology json',
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type=str, required=False, default='./topology.json')
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parser.add_argument('-l', '--log-dir', type=str, required=False, default=default_logs)
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parser.add_argument('-p', '--pcap-dir', type=str, required=False, default=default_pcaps)
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parser.add_argument('-j', '--switch_json', type=str, required=True)
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parser.add_argument('-b', '--behavioral-exe', help='Path to behavioral executable',
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type=str, required=False, default='simple_switch')
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return parser.parse_args()
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if __name__ == '__main__':
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args = get_args()
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exercise = ExerciseRunner(args.topo, args.log_dir, args.pcap_dir,
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args.switch_json, args.behavioral_exe, args.quiet)
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exercise.run_exercise()
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