def __init__(self, config_file='laptop_demo_network.json'):
frenetic.App.__init__(self)
nib = NetworkInformationBase()
self.nib = nib
nib.load_config(config_file)
self.arp_handler = ArpHandler(self, nib)
self.intranet_handler = IntranetHandler(self, nib)
self.cross_campus_handler = CrossCampusHandler(self, nib)
class CoscinSwitchApp(frenetic.App):
client_id = "coscin_switch"
frenetic_http_host = "localhost"
frenetic_http_port = "9000"
# The switch can be in one of three states
STATE_INITIAL_CONFIG = 0
STATE_ROUTER_LEARNING = 1
STATE_NORMAL_OPERATION = 2
state = STATE_INITIAL_CONFIG
# Used as destination Mac for ARP replies that we ignore
BOGUS_MAC = "00:de:ad:00:be:ef"
def __init__(self, config_file='laptop_demo_network.json'):
frenetic.App.__init__(self)
nib = NetworkInformationBase()
self.nib = nib
nib.load_config(config_file)
self.arp_handler = ArpHandler(self, nib)
self.intranet_handler = IntranetHandler(self, nib)
self.cross_campus_handler = CrossCampusHandler(self, nib)
#self.broadcast_handler = BroadcastHandler(self, nib)
##################################
# Common operations
# Send payload to all ports
def flood(self, switch, except_port, payload):
flood_to_ports = [ p for p in self.nib.switches[switch] if p != except_port ]
output_actions = [ Output(Physical(p)) for p in flood_to_ports ]
# Only bother to send the packet out if there are ports to send it out on.
if output_actions:
self.pkt_out(self.nib.switch_to_dpid(switch), payload, output_actions)
def arp_payload(self, e, pkt):
p = packet.Packet()
p.add_protocol(e)
p.add_protocol(pkt)
p.serialize()
return NotBuffered(binascii.a2b_base64(binascii.b2a_base64(p.data)))
def send_arp_request(self, switch, src_ip, target_ip):
# It's unclear what the source should be, since the switch has no mac or IP address.
# It just hears all replies and picks out the interesting stuff.
src_mac = self.BOGUS_MAC
dst_mac = "ff:ff:ff:ff:ff:ff"
e = ethernet.ethernet(dst=dst_mac, src=src_mac, ethertype=ether.ETH_TYPE_ARP)
pkt = arp.arp_ip(arp.ARP_REQUEST, src_mac, src_ip, "00:00:00:00:00:00", target_ip)
payload = self.arp_payload(e, pkt)
logging.info("Sending Arp Request to "+target_ip)
# None means the request will go out every available port
self.flood(switch, None, payload)
def send_arp_request_router_interface(self, switch, target_ip_net):
# Note this may not or may not be a real host, but the reply will always come back to the switch anyway.
# TODO: host 250 is appropriate for /24 subnets, but not anything smaller
src_ip = NetUtils.ip_for_network(target_ip_net, 250)
dst_ip = NetUtils.ip_for_network(target_ip_net, 1) # The IP of the router interface will always be a .1
self.send_arp_request(switch, src_ip, dst_ip)
def update_and_clear_dirty(self):
self.update(self.normal_operation_policy())
self.nib.clear_dirty()
########################
# Frenetic Dispatchers
def connected(self):
def handle_current_switches(switches):
self.nib.save_switches_and_ports(switches)
logging.info("Connected to Frenetic - Switches: "+self.nib.switch_description())
logging.info("Installing router learning rules")
self.update(self.router_learning_policy())
logging.info("Pausing 2 seconds to allow rules to be installed")
IOLoop.instance().add_timeout(datetime.timedelta(seconds=2), self.learn_routers)
# If Frenetic went down, it'll call connected() when it comes back up. In that case, just
# resend the current policies
if self.state == self.STATE_NORMAL_OPERATION:
self.update_and_clear_dirty()
else:
# Turn on remove_tail_drops to get around issue 463
#self.config( CompilerOptions("empty", "IP4Dst < EthType < Location < IP4Src < Switch", True, False, True) )
self.current_switches(callback=handle_current_switches)
def packet_in(self, dpid, port, payload):
if self.state == self.STATE_INITIAL_CONFIG:
logging.info("Packets received before initialization, dropping" )
elif self.state == self.STATE_ROUTER_LEARNING:
self.packet_in_router_learning(dpid, port, payload)
else:
self.packet_in_normal_operation(dpid, port, payload)
# TODO: Bizarrely, port_up events from an HP switch are reported as port_down and vice-versa.
# I don't know if the problem is in the switch, Frenetic, or the language bindings.
def port_down(self, dpid, port):
switch = self.nib.dpid_to_switch(dpid)
logging.info("Port up: "+switch+"/"+str(port))
# If port comes up, remove any learned macs on it (probably won't be any). This is necessary
# in case port_down was not fired.
if self.nib.unlearn_mac_on_port(switch, port):
self.update_and_clear_dirty()
def port_up(self, dpid, port):
switch = self.nib.dpid_to_switch(dpid)
logging.info("Port down: "+switch+"/"+str(port))
# If port goes down, remove any learned macs on it
if self.nib.unlearn_mac_on_port(switch, port):
self.update_and_clear_dirty()
def switch_up(self, dpid, ports):
switch = self.nib.dpid_to_switch(dpid)
# If we've seen this switch before, just return. Otherwise add the ports to unlearned.
if self.nib.contains_switch(switch):
return
self.nib.add_switches_and_ports(switch, ports)
self.update_and_clear_dirty()
logging.info("Updated Switches: "+self.nib.switch_description())
# Don't remove switch info when it supposedly goes down. That way if it comes back up
# without properly signalling switch_up, we're not over a barrel.
def switch_down(self, dpid):
switch = self.nib.dpid_to_switch(dpid)
logging.info("Switch down: "+switch)
########################
# Router Learning Mode
# We assume all router interfaces are up for all alternate paths and that they're fixed for the duration
# of the controller. In this mode, we send ARP requests to all paths so we can learn (1) their Mac address
# (2) their switch port.
# RouterLearningHandler.packet_in
def packet_in_router_learning(self, dpid, port, payload):
p = NetUtils.packet(payload, 'arp')
p_eth = NetUtils.packet(payload, 'ethernet')
switch = self.nib.dpid_to_switch(dpid)
logging.info("Received ("+str(p_eth.ethertype)+"): "+p_eth.src+"/"+p.src_ip+" -> ("+switch+", "+str(port)+") -> "+p.dst_ip)
# Supposedly, the src mac in the ARP reply and the ethernet frame itself should be the
# the same, but that's not always the case. The Ethernet frame is definitive.
self.nib.learn(switch, self.nib.ROUTER_PORT, port, p_eth.src, p.src_ip)
self.waiting_for_router_arps -= 1
if self.waiting_for_router_arps == 0:
self.normal_mode()
# RouterLearningHandler.policy
def router_learning_policy(self):
# In the intial config, grab all ARP replies for ourselves
return Filter( Policies.is_arp() ) >> Policies.send_to_controller()
# RouterLearningHandler.start
def learn_routers(self):
logging.info("Switching to Router Learning mode")
self.state = self.STATE_ROUTER_LEARNING
self.waiting_for_router_arps = 0
for side in [ "ithaca", "nyc" ]:
if self.nib.switch_present(side):
self.send_arp_request_router_interface(side, self.nib.actual_net_for(side))
self.waiting_for_router_arps += 1
########################
# Normal Mode
# This basically handles all traffic afterwards. It learns host ports coming up.
def normal_mode(self):
logging.info("Switching to Normal mode. Host ports to learn: "+self.nib.unlearned_ports_description())
self.update(self.normal_operation_policy())
self.state = self.STATE_NORMAL_OPERATION
def normal_operation_policy(self):
return Union([
self.arp_handler.policy(),
#self.broadcast_handler.policy(),
self.intranet_handler.policy(),
self.cross_campus_handler.policy()
])
def packet_in_normal_operation(self, dpid, port, payload):
switch = self.nib.dpid_to_switch(dpid)
# TODO: deal with non-IP packets, although that's fairly unlikely
p_eth = NetUtils.packet(payload, 'ethernet')
if p_eth.ethertype == 0x0806:
p_arp = NetUtils.packet(payload, 'arp')
src_ip = p_arp.src_ip
dst_ip = p_arp.dst_ip
elif p_eth.ethertype == 0x0800:
p_ip = NetUtils.packet(payload, 'ipv4')
src_ip = p_ip.src
dst_ip = p_ip.dst
else:
src_ip = '0.0.0.0'
dst_ip = '0.0.0.0'
logging.info("Received packet of type "+str(p_eth.ethertype))
# TODO: Handle DHCP requests someday, ... maybe
if src_ip == '0.0.0.0':
return
if self.nib.learn(switch, self.nib.ENDHOST_PORT, port, p_eth.src, src_ip):
self.nib.set_dirty()
logging.info("Received ("+str(p_eth.ethertype)+"): "+p_eth.src+"/"+src_ip+" -> ("+switch+", "+str(port)+") -> "+dst_ip)
self.arp_handler.packet_in(dpid, port, payload)
#self.broadcast_handler.packet_in(dpid, port, payload)
self.intranet_handler.packet_in(dpid, port, payload)
self.cross_campus_handler.packet_in(dpid, port, payload)
if self.nib.is_dirty():
logging.info("Installing new policy")
# This doesn't actually wait two seconds, but it seems to serialize the updates so they occur in the right
# order, as opposed to just calling update_and_clear_dirty on its own.
IOLoop.instance().add_timeout(datetime.timedelta(seconds=2), self.update_and_clear_dirty)
def set_preferred_path(self, new_preferred_path):
# Send pings
preferred_path = self.nib.get_preferred_path()
logging.info("Adjusting preferred path from "+str(preferred_path)+" to "+str(new_preferred_path))
# Setting a preferred path is pretty hard on the switch - it sends a whole new flow table
# so don't do it unless absolutely necessary
if preferred_path == new_preferred_path:
logging.info("No change.")
else:
self.nib.set_preferred_path(new_preferred_path)
self.update(self.normal_operation_policy())
