def test_put_route():
fib = Fib()
fib.put_route("4.0.0.0/8", ["nh1", "nh2"])
fib.put_route("4.1.0.0/16", ["nh3"])
fib.put_route("4.0.0.0/8", ["nh1", "nh4"])
assert str(fib) == ("4.0.0.0/8 -> nh1, nh4\n"
"4.1.0.0/16 -> nh3\n")
def test_get_repr():
fib = Fib()
fib.put_route("2.0.0.0/8", ["nh1", "nh2"])
fib.put_route("1.1.1.1/32", ["nh1"])
fib.put_route("2.2.1.0/24", ["nh1", "nh3"])
assert str(fib) == ("1.1.1.1/32 -> nh1\n"
"2.0.0.0/8 -> nh1, nh2\n"
"2.2.1.0/24 -> nh1, nh3\n")
def test_del_route():
fib = Fib()
fib.put_route("4.0.0.0/8", ["nh1", "nh2"])
fib.del_route("4.0.0.0/8")
fib.del_route("3.0.0.0/8")
assert str(fib) == ("")
def test_get_route():
fib = Fib()
fib.put_route("4.0.0.0/8", ["nh1", "nh2"])
assert str(fib.get_route("4.0.0.0/8")) == "4.0.0.0/8 -> nh1, nh2"
assert fib.get_route("3.0.0.0/8") is None
class Rib:
"""
Class representing the RIB of a node.
Attributes of this class are:
- destinations: a Patricia Trie. Keys are IP prefixes and values are Destination objects
- fib: instance of the FIB of this node
"""
def __init__(self):
self.destinations = pytricia.PyTricia()
self.fib = Fib()
def put_route(self, route):
"""
Add a RibRoute object to the Destination object associated to the prefix.
:param route: (RibRoute) the object to add to the Destination associated to the prefix
:return:
"""
# If there is no Destination object for the prefix, create a new Destination object
# for the given prefix and insert it in the Trie
if not self.destinations.has_key(route.prefix):
prefix_destination = Destination(self, route.prefix)
self.destinations.insert(route.prefix, prefix_destination)
else:
prefix_destination = self.destinations.get(route.prefix)
# Insert desired route in destination object
best_changed = prefix_destination.put_route(route)
# Get children prefixes before performing actions on the prefix (it can be deleted from the Trie)
children_prefixes = self.destinations.children(
prefix_destination.prefix)
# TODO: ask if this case can occur
# update_fib = True
# if prefix_dest.parent_prefix_dest is not None and \
# prefix_dest.best_route.next_hops == prefix_dest.parent_prefix_dest.best_route.next_hops:
# del self.destinations[prefix_dest.prefix]
# self.fib.delete_route(prefix_dest.prefix)
# update_fib = False
#
# if update_fib:
# If best route changed in Destination object
if best_changed:
# Update prefix in the fib
self.fib.put_route(prefix_destination.best_route)
# Try to delete superfluous children
if not self._delete_superfluous_children(prefix_destination,
children_prefixes):
# If children have not been deleted, update them
self._update_prefix_children(children_prefixes)
def del_route(self, prefix, owner):
"""
Delete given prefix and owner RibRoute object.
If no more RibRoute objects are available, also delete Destination from trie and from the FIB.
:param prefix: (string) prefix to delete
:param owner: (int) owner of the prefix
:return: (boolean) if the route has been deleted or not
"""
destination_deleted = False
best_changed = False
children_prefixes = None
# Check if the prefix is stored in the trie
if self.destinations.has_key(prefix):
# Get children prefixes before performing actions on the prefix (it can be deleted from the Trie)
children_prefixes = self.destinations.children(prefix)
destination = self.destinations.get(prefix)
# Delete route from the Destination object
deleted, best_changed = destination.del_route(owner)
# Route was not present in Destination object, nothing to do
if not deleted:
return
if not destination.routes:
# No more routes available for current prefix, delete it from trie and FIB
self.destinations.delete(prefix)
self.fib.delete_route(prefix)
destination_deleted = True
elif best_changed:
# Best route changed, push it in the FIB
self.fib.put_route(destination.best_route)
else:
deleted = False
if deleted and (best_changed or destination_deleted):
# If route has been deleted and an event occurred (best changed or destination deleted), update children
self._update_prefix_children(children_prefixes)
return deleted
def _update_prefix_children(self, children_prefixes):
"""
Refresh children next hops
:param children_prefixes: (list) all the children at each level of a given prefix
:return:
"""
for child_prefix in children_prefixes:
child_prefix_dest = self.destinations.get(child_prefix)
self.fib.put_route(child_prefix_dest.best_route)
def _delete_superfluous_children(self, prefix_dest, children_prefixes):
"""
Delete superfluous children of the given prefix from the RIB and the FIB when it is unreachable
:param prefix_dest: (Destination) object to check for superfluous children
:param children_prefixes: (list) children of given prefix
:return: (boolean) if children of the given prefix have been removed or not
"""
best_route = prefix_dest.best_route
if (not best_route.positive_next_hops and best_route.negative_next_hops) and not best_route.next_hops \
and prefix_dest.parent_prefix_dest:
for child_prefix in children_prefixes:
self.destinations.delete(child_prefix)
self.fib.delete_route(child_prefix)
return True
return False
def __str__(self):
rep_str = ""
for prefix in self.destinations:
rep_str += str(self.destinations.get(prefix))
return "RIB:\n%s\n\nFIB:\n%s" % (rep_str, str(self.fib))
def __repr__(self):
return str(self)