def repair_links(cut_this_round):
for link in set(self.cut_links):
if link in cut_this_round:
continue
if self.random.random() < self.link_recovery_rate:
msg.event("Restoring link %s" % str(link))
link.start_switch_impl.bring_port_up(link.start_port)
self.cut_links.remove(link)
def restart_switches(crashed_this_round):
for switch_impl in set(self.failed_switches):
if switch_impl in crashed_this_round:
continue
if self.random.random() < self.switch_recovery_rate:
msg.event("Rebooting switch_impl %s" % str(switch_impl))
switch_impl.recover()
self.failed_switches.remove(switch_impl)
def crash_switches():
crashed_this_round = set()
for switch_impl in self.live_switches:
if self.random.random() < self.switch_failure_rate:
msg.event("Crashing switch_impl %s" % str(switch_impl))
switch_impl.fail()
crashed_this_round.add(switch_impl)
self.failed_switches.add(switch_impl)
return crashed_this_round
def fuzz_traffic(self):
if not self.dataplane_trace:
# randomly generate messages from switches
for switch_impl in self.live_switches:
if self.random.random() < self.traffic_generation_rate:
if len(switch_impl.ports) > 0:
msg.event("injecting a random packet")
traffic_type = "icmp_ping"
# Generates a packet, and feeds it to the switch_impl
self.traffic_generator.generate(traffic_type, switch_impl)
def sever_links():
# TODO: model administratively down links? (OFPPC_PORT_DOWN)
cut_this_round = set()
for link in self.live_links:
if self.random.random() < self.link_failure_rate:
msg.event("Cutting link %s" % str(link))
self.cut_links.add(link)
link.start_switch_impl.take_port_down(link.start_port)
cut_this_round.add(link)
return cut_this_round
def loop(self, steps=None):
self.running = True
end_time = self.logical_time + steps if steps else sys.maxint
while self.running and self.logical_time < end_time:
self.logical_time += 1
self.trigger_events()
msg.event("Round %d completed." % self.logical_time)
if self.interactive:
# TODO: print out the state of the network at each timestep? Take a
# verbose flag..
self.invariant_check_prompt()
self.dataplane_trace_prompt()
answer = msg.raw_input('Continue to next round? [Yn]').strip()
if answer != '' and answer.lower() != 'y':
self.stop()
break
else: # not self.interactive
if (self.logical_time % self.check_interval) == 0:
# Time to run correspondence!
# spawn a thread for running correspondence. Make sure the controller doesn't
# think we've gone idle though: send OFP_ECHO_REQUESTS every few seconds
# TODO: this is a HACK
def do_correspondence():
any_policy_violations = self.invariant_checker.check_correspondence(self.live_switches, self.live_links, self.access_links)
if any_policy_violations:
msg.fail("There were policy-violations!")
else:
msg.interactive("No policy-violations!")
thread = threading.Thread(target=do_correspondence)
thread.start()
while thread.isAlive():
for switch in self.live_switches:
# connection -> deferred io worker -> io worker
switch.send(of.ofp_echo_request().pack())
thread.join(2.0)
if self.dataplane_trace and (self.logical_time % self.trace_interval) == 0:
self.inject_trace_event()
time.sleep(self.delay)
def check_dataplane(self):
''' Decide whether to delay, drop, or deliver packets '''
for dp_event in set(self.panel.get_buffered_dp_events()):
if self.random.random() < self.dataplane_delay_rate:
msg.event("Delaying dataplane event")
# (Monkey patch on a delay counter)
if not hasattr(dp_event, "delayed_rounds"):
dp_event.delayed_rounds = 0
dp_event.delayed_rounds += 1
elif self.random.random() < self.dataplane_drop_rate:
msg.event("Dropping dataplane event")
# Drop the message
self.panel.drop_dp_event(dp_event)
self.dropped_dp_events.append(dp_event)
else:
(next_hop, next_port) = self.panel.get_connected_port(dp_event.switch, dp_event.port)
if type(dp_event.node) == Host or type(next_hop) == Host:
# TODO: model access link failures:
self.panel.permit_dp_event(dp_event)
else:
link = Link(dp_event.switch, dp_event.port, next_hop, next_port)
if not link in self.cut_links:
msg.event("Forwarding dataplane event")
# Forward the message
self.panel.permit_dp_event(dp_event)
