def handle_route_advertisement(self, route_dst, route_latency, port):
"""
Called when the router receives a route advertisement from a neighbor.
:param route_dst: the destination of the advertised route.
:param route_latency: latency from the neighbor to the destination.
:param port: the port that the advertisement arrived on.
:return: nothing.
"""
# TODO: fill this in!
if route_dst in self.table:
current_route = self.table.get(route_dst)
if (route_latency + self.ports.get_latency(port) <
current_route.latency) or (port
== self.table[route_dst].port):
if route_latency >= INFINITY:
self.table[route_dst] = TableEntry(route_dst, port,
route_latency,
api.current_time())
else:
self.table[route_dst] = TableEntry(
route_dst, port,
route_latency + self.ports.get_latency(port),
api.current_time() + self.ROUTE_TTL)
else:
if (route_latency < INFINITY):
self.table[route_dst] = TableEntry(
route_dst, port,
route_latency + self.ports.get_latency(port),
api.current_time() + self.ROUTE_TTL)
def handle_route_advertisement(self, route_dst, route_latency, port):
"""
Called when the router receives a route advertisement from a neighbor.
:param route_dst: the destination of the advertised route.
:param route_latency: latency from the neighbor to the destination.
:param port: the port that the advertisement arrived on.
:return: nothing.
"""
# TODO: fill this in!
# if its not in the table entry then I need to add it since it is a new destination
if route_dst not in self.table.keys():
self.table[route_dst] = TableEntry(
route_dst, port,
self.ports.get_latency(port) + route_latency,
api.current_time() + self.ROUTE_TTL)
else:
for host, entry in self.table.items():
if route_dst == host: # if my destination is in my table entry then maybe I have found a better path and must update my existing path
if port == entry.port and route_latency >= INFINITY:
self.table[host] = TableEntry(route_dst, port,
INFINITY,
api.current_time())
self.send_routes(False)
elif port == entry.port or entry.latency > route_latency + self.ports.get_latency(
port):
self.table[host] = TableEntry(
route_dst, port,
route_latency + self.ports.get_latency(port),
api.current_time() + self.ROUTE_TTL)
self.send_routes(False)
def expire_routes(self):
"""
Clears out expired routes from table.
accordingly.
"""
# TODO: fill this in!
hosts = list(self.table.keys())
for host in hosts:
table_entry = self.table[host]
if table_entry.expire_time == FOREVER:
return
# route is poison and expired
if self.POISON_EXPIRED and api.current_time(
) > table_entry.expire_time:
current_route = self.table[host]
poison_route = TableEntry(host,
current_route.port,
latency=INFINITY,
expire_time=self.ROUTE_TTL)
self.table[host] = poison_route
# route is expired
elif api.current_time() > table_entry.expire_time:
del self.table[host]
def handle_route_advertisement(self, route_dst, route_latency, port):
"""Called when the router receives a route advertisement from a neighbor.
:param route_dst: the destination of the advertised route.
:param route_latency: latency from the neighbor to the destination.
:param port: the port that the advertisement arrived on.
:return: nothing."""
# TODO: fill this in!
port_latency = self.ports.get_latency(port)
new_latency = port_latency + route_latency
new_expire_time = api.current_time() + self.ROUTE_TTL
current_route = self.table.get(route_dst)
new_route = TableEntry(dst=route_dst,
port=port,
latency=new_latency,
expire_time=new_expire_time)
# poison advertisement
if route_latency >= INFINITY and current_route.port == port:
current_expire_time = current_route.expire_time
poison_route = TableEntry(dst=route_dst,
port=port,
latency=INFINITY,
expire_time=current_expire_time)
self.table[route_dst] = poison_route
self.send_routes(force=False)
return
# if NO route currently exists, add/update the new route
if not current_route:
self.table[route_dst] = new_route
self.send_routes(force=False)
return
# found a better route
if new_latency < current_route.latency:
self.table[route_dst] = new_route
self.send_routes(force=False)
return
if current_route.port == port:
self.table[route_dst] = new_route
self.send_routes(force=False)
return
def handle_route_advertisement(self, route_dst, route_latency, port):
"""
Called when the router receives a route advertisement from a neighbor.
:param route_dst: the destination of the advertised route.
:param route_latency: latency from the neighbor to the destination.
:param port: the port that the advertisement arrived on.
:return: nothing.
"""
if route_dst not in self.table or route_latency+self.ports.get_latency(port)<self.table[route_dst].latency or (port == self.table[route_dst].port and self.table[route_dst].latency<INFINITY):
self.table[route_dst] = TableEntry(dst=route_dst,port=port,latency=min(INFINITY,route_latency+self.ports.get_latency(port)),expire_time=api.current_time()+self.ROUTE_TTL)
self.send_routes()
def add_static_route(self, host, port):
"""
Adds a static route to this router's table.
Called automatically by the framework whenever a host is connected
to this router.
:param host: the host.
:param port: the port that the host is attached to.
:returns: nothing.
"""
# `port` should have been added to `peer_tables` by `handle_link_up`
# when the link came up.
self.table[host] = TableEntry(dst=host,port=port,latency=self.ports.get_latency(port),expire_time=FOREVER)
self.send_routes()
assert port in self.ports.get_all_ports(), "Link should be up, but is not."
def expire_routes(self):
"""
Clears out expired routes from table.
accordingly.
"""
l = []
for host,link in self.table.items():
if api.current_time()>link.expire_time:
self.s_log("Route from {} to {} is expired.",self,host)
l.append(host)
for to_delete in l:
if self.POISON_EXPIRED:
self.table[to_delete] = TableEntry(dst = to_delete,port = self.table[to_delete].port,latency = INFINITY, expire_time=api.current_time()+self.ROUTE_TTL)
#self.send_routes()
else:
del self.table[to_delete]
def expire_routes(self):
"""
Clears out expired routes from table.
accordingly.
"""
# TODO: fill this in!
toDelete = []
if self.POISON_EXPIRED is True:
for host, entry in self.table.items():
if entry.has_expired:
self.table[host] = TableEntry(host, entry.port, INFINITY,
api.current_time())
else:
for host, entry in self.table.items():
if entry.has_expired:
toDelete.append(host)
self.deleteRoutes(toDelete)
def handle_link_down(self, port):
"""
Called by the framework when a link attached to this router does down.
:param port: the port number used by the link.
:returns: nothing.
"""
del self.history[port]
self.ports.remove_port(port)
if not self.POISON_ON_LINK_DOWN:
return
l = []
for host,link in self.table.items():
if link.port == port:
self.s_log("Route from {} to {} is down.",self,host)
l.append(host)
for to_delete in l:
self.table[to_delete] = TableEntry(dst = to_delete,port = self.table[to_delete].port,latency = INFINITY, expire_time=api.current_time()+self.ROUTE_TTL)
self.send_routes()
def handle_link_down(self, port):
"""
Called by the framework when a link attached to this router does down.
:param port: the port number used by the link.
:returns: nothing.
"""
self.ports.remove_port(port)
# TODO: fill this in!
toDelete = []
for host, entry in self.table.items():
if entry.port == port:
if self.POISON_ON_LINK_DOWN:
self.table[host] = TableEntry(
host, port, INFINITY,
api.current_time() + self.ROUTE_TTL)
self.send_routes(False)
else:
toDelete.append(host)
self.deleteRoutes(toDelete)
def expire_routes(self):
"""
Clears out expired routes from table.
accordingly.
"""
# TODO: fill this in!
keys = self.table.items()
delete = []
for dst, entry in keys:
if entry.has_expired:
delete.append(dst)
if not self.POISON_EXPIRED:
for dest in delete:
self.table.pop(dest)
else:
for dest in delete:
self.table[dest] = TableEntry(
dest, self.table[dest].port, INFINITY,
api.current_time() + self.ROUTE_TTL)
def handle_link_down(self, port):
"""
Called by the framework when a link attached to this router does down.
:param port: the port number used by the link.
:returns: nothing.
"""
self.ports.remove_port(port)
# TODO: fill this in!
for host in list(self.table.keys()):
if self.table[host].port == port:
if self.POISON_ON_LINK_DOWN:
# poison and immediately send any routes that need to be updated
poison_route = TableEntry(
host,
port,
latency=INFINITY,
expire_time=self.table[host].expire_time)
self.table[host] = poison_route
self.send_routes(force=False)
# remove any routes that go through that link
del self.table[host]