def egress_src_dest_pairs_policy(self):
policies = []
for src_dest_pair in self.nib.get_egress_src_dest_pairs():
(src_ip, dst_ip) = src_dest_pair
# Convert dst_ip to its real form. First find out what the egress switch actually is:
for ap in self.nib.alternate_paths():
if NetUtils.ip_in_network(dst_ip, ap["ithaca"]):
switch = "ithaca"
imaginary_net = ap["ithaca"]
elif NetUtils.ip_in_network(dst_ip, ap["nyc"]):
switch = "nyc"
imaginary_net = ap["nyc"]
real_net = self.nib.actual_net_for(switch)
dst_host = NetUtils.host_of_ip(dst_ip, imaginary_net)
new_dest_ip = NetUtils.ip_for_network(real_net, dst_host)
# If it's not in the ARP cache, it already has an ARP request on the way so ignore it for now.
if self.nib.learned_ip(new_dest_ip):
direct_net_port = self.nib.port_for_ip(new_dest_ip)
new_src_ip = self.nib.translate_alternate_net(src_ip)
output_actions = SetIP4Src(new_src_ip) >> SetIP4Dst(new_dest_ip) >> Send(direct_net_port)
policies.append(
Filter(SwitchEq(self.nib.switch_to_dpid(switch)) & Policies.is_ip_from_to(src_ip, dst_ip))
>> output_actions
)
return Union(policies)
def ingress_src_dest_pairs_policy(self):
policies = []
for src_dest_pair in self.nib.get_ingress_src_dest_pairs():
(src_ip, dst_ip) = src_dest_pair
switch = self.nib.switch_for_ip(src_ip)
dpid = self.nib.switch_to_dpid(switch)
port = self.nib.port_for_ip(src_ip)
src_host = NetUtils.host_of_ip(src_ip, self.nib.actual_net_for(switch))
# If this is going to the preferred network, write a rule choosing the
# correct route here.
opposite_switch = self.nib.opposite_switch(switch)
if NetUtils.ip_in_network(dst_ip, self.nib.actual_net_for(opposite_switch)):
# Get host from src_ip
src_pref_net = self.nib.preferred_net(switch)
new_src = NetUtils.ip_for_network(src_pref_net, src_host)
dest_host = NetUtils.host_of_ip(dst_ip, self.nib.actual_net_for(opposite_switch))
new_dest = NetUtils.ip_for_network(self.nib.preferred_net(opposite_switch), dest_host)
router_port = self.nib.router_port_for_switch(switch)
output_actions = SetIP4Src(new_src) >> SetIP4Dst(new_dest) >> Send(router_port)
policies.append(
Filter(Policies.at_switch_port(dpid, port) & Policies.is_ip_from_to(src_ip, dst_ip))
>> output_actions
)
else:
# It's a direct path. Find the path first.
for ap in self.nib.alternate_paths():
if NetUtils.ip_in_network(dst_ip, ap[opposite_switch]):
alternate_path = ap
new_src = NetUtils.ip_for_network(alternate_path[switch], src_host)
router_port = self.nib.router_port_for_switch(switch)
output_actions = SetIP4Src(new_src) >> Send(router_port)
policies.append(
Filter(Policies.at_switch_port(dpid, port) & Policies.is_ip_from_to(src_ip, dst_ip))
>> output_actions
)
return Union(policies)
def policy(self):
# One rule sends all traffic from unlearned ports to controller.
is_at_unlearned_port = []
unlearned_ports = self.nib.get_unlearned_ports()
for switch, ports in unlearned_ports.iteritems():
dpid = self.nib.switch_to_dpid(switch)
for port in ports:
is_at_unlearned_port.append(Policies.at_switch_port(dpid,port))
policies = [ Filter(Or(is_at_unlearned_port)) >> Policies.send_to_controller() ]
# Output rules for each pair of learned endhosts so intranet traffic can be handled nicely on
# the switch.
# TODO: If the app is restarted but hosts are hanging onto ARP cache entries, they won't be able
# to get packets to each other. This is hard to handle because a "Port = n AND Dest Net = this"
# might have overlap with other rules ... I think
# Therefore, I'm letting this go for now because (1) intranet host
# traffic is relatively rare (2) ARP cache entries usually timeout in 10 minutes anyway.
# L2Switch.policy.
for switch in self.nib.switches_present():
dpid = self.nib.switch_to_dpid(switch)
# The router interface is no different than a regular host with regard to intranet traffic.
all_hosts = copy.deepcopy(self.nib.get_endhosts(switch))
all_hosts.append( (None, self.nib.router_port_for_switch(switch) , None, self.nib.router_ip_for_switch(switch) ) )
for src_endhost in all_hosts:
(_, src_port, _, src_ip) = src_endhost
for dst_endhost in all_hosts:
(_, dst_port, _, dst_ip) = dst_endhost
# No rule for a host to itself, obviously
if src_ip != dst_ip:
policies.append(
Filter(Policies.is_ip_from_to(src_ip, dst_ip) & Policies.at_switch_port(dpid, src_port) )
>> Send(dst_port)
)
policies.append(
Filter(Policies.is_arp_from_to(src_ip, dst_ip) & Policies.at_switch_port(dpid, src_port) )
>> Send(dst_port)
)
return Union(policies)
