def __init__(self, k, gamma):
random.seed()
# RangeBST lets you efficiently lookup nodes in a range of positions
self.nodes = RangeBST()
self.k = k
self.gamma = gamma
self.two_above_array = [1.0 / pow(2, i) for i in range(400)]
self.quorums = {}
self.log = 0
self.redo_quorums()
def __init__(self, k, gamma):
random.seed()
# RangeBST lets you efficiently lookup nodes in a range of positions
self.nodes = RangeBST()
self.k = k
self.gamma = gamma
self.two_above_array = [1.0 / pow(2, i) for i in range(400)]
self.quorums = {}
self.log = 0
self.redo_quorums()
class CuckooNetwork(object):
def __init__(self, k, gamma):
random.seed()
# RangeBST lets you efficiently lookup nodes in a range of positions
self.nodes = RangeBST()
self.k = k
self.gamma = gamma
self.two_above_array = [1.0 / pow(2, i) for i in range(400)]
self.quorums = {}
self.log = 0
self.redo_quorums()
def clone(self):
c = CuckooNetwork(self.k, self.gamma)
c.nodes = copy.deepcopy(self.nodes)
c.quorums = self.quorums
c.log = self.log
return c
def random_pos(self):
return random.random()
def __len__(self):
return len(self.nodes)
def two_above(self, val):
if val >= 1.0:
return 1.0
# We've cached the 1/powers of 2 values in self.two_above_array
for (r, aval) in enumerate(self.two_above_array):
if val > aval:
return self.two_above_array[r - 1]
elif val == aval:
return aval
raise Exception("Unknown above")
def k_region_nodes(self, pos):
(start, end) = self.k_region(pos)
return self.nodes.range(start, end)
def k_region(self, pos):
kr_size = self.k_region_size()
reg = math.floor(pos / kr_size)
return (kr_size * reg, kr_size * (reg + 1))
def k_region_size(self):
if len(self) == 0:
return 1.0
# Assume network knows log estimate of size
# and not actual size
n = float(pow(2, self.log))
# Get the size of a k-region
return self.two_above(self.k / n)
def remove(self, node):
self.remove_from_quorums(node)
self.nodes.remove(node.pos)
# Did we just shrink the network by a log size?
# If so, it's time to adjust quorum size
if len(self) == 0:
self.quorums = {}
elif int(math.log(len(self), 2)) < self.log:
self.log = int(math.log(len(self), 2))
self.redo_quorums()
def remove_from_quorums(self, node):
reg = self.quorum_region(node.pos)
self.quorums[reg].remove(node)
def add_to_quorums(self, node):
reg = self.quorum_region(node.pos)
self.quorums[reg].add(node)
def bootstrap_join(self, node):
node.pos = self.random_pos()
self.nodes.add(node.pos, node)
self.add_to_quorums(node)
# Did we just grow the network by a log size?
# If so, it's time to adjust quorum size
if math.floor(math.log(len(self), 2)) > self.log:
self.log = math.floor(math.log(len(self), 2))
self.redo_quorums()
def join(self, node, update_quorums=False):
# Pick a random location
rand = self.random_pos()
evict = self.k_region_nodes(rand)
# Reposition the other nodes in the k-region
for evicted in evict:
self.remove_from_quorums(evicted)
self.nodes.remove(evicted.pos)
# Secondary join (no evicting)
evicted.pos = self.random_pos()
self.nodes.add(evicted.pos, evicted)
self.add_to_quorums(evicted)
# Add the new node
node.pos = rand
self.add_to_quorums(node)
self.nodes.add(node.pos, node)
# Did we just grow the network by a log size?
# If so, it's time to adjust quorum size
if math.floor(math.log(len(self), 2)) > self.log:
self.log = math.floor(math.log(len(self), 2))
self.redo_quorums()
def quorum_size(self, pos):
reg = self.quorum_region(pos)
return len(self.quorums[reg])
def avg_quorum_size(self):
sum = 0.0
for q in self.quorums.itervalues():
sum += len(q)
return sum / len(self.quorums)
def quorum_region_size(self):
# gamma*log(n) k_regions
# where gamma is a small integer
if self.log == 0:
return 1.0
# Get the size of a k-region
g = float(self.gamma)
return self.two_above(self.k_region_size() * (g * self.log))
def quorum_region(self, pos):
q_size = self.quorum_region_size()
reg = math.floor(pos / q_size)
return (q_size * reg, q_size * (reg + 1))
def redo_quorums(self):
self.quorums = {}
q_size = self.quorum_region_size()
cur = 0.0
while cur < 1.0:
self.quorums[(cur, cur + q_size)] = set()
cur += q_size
for node in self.nodes:
r = self.quorum_region(node.pos)
self.quorums[r].add(node)
def verify(self):
# Verify each quorum region has no more than 1/4 byzantine
for quorum in self.quorums.itervalues():
bad = len([1 for n in quorum if n.byzantine])
if float(bad) / len(quorum) > 0.25:
return False
return True
def byzantine_from_least_faulty_quorum(self):
faultiness = {}
for (r, quorum) in self.quorums.iteritems():
bad = len([1 for n in quorum if n.byzantine])
faultiness[r] = float(bad) / len(quorum)
# Find the least faulty
least = (1.1, None)
for (r, fault) in faultiness.iteritems():
if fault < least[0] and fault > 0.0:
least = (fault, r)
least_q = self.quorums[least[1]]
# return the first byzantine node in this quorum
for node in least_q:
if node.byzantine:
return node
raise Exception("No node found")
class CuckooNetwork(object):
def __init__(self, k, gamma):
random.seed()
# RangeBST lets you efficiently lookup nodes in a range of positions
self.nodes = RangeBST()
self.k = k
self.gamma = gamma
self.two_above_array = [1.0 / pow(2, i) for i in range(400)]
self.quorums = {}
self.log = 0
self.redo_quorums()
def clone(self):
c = CuckooNetwork(self.k, self.gamma)
c.nodes = copy.deepcopy(self.nodes)
c.quorums = self.quorums
c.log = self.log
return c
def random_pos(self):
return random.random()
def __len__(self):
return len(self.nodes)
def two_above(self, val):
if val >= 1.0:
return 1.0
# We've cached the 1/powers of 2 values in self.two_above_array
for (r, aval) in enumerate(self.two_above_array):
if val > aval:
return self.two_above_array[r - 1]
elif val == aval:
return aval
raise Exception("Unknown above")
def k_region_nodes(self, pos):
(start, end) = self.k_region(pos)
return self.nodes.range(start, end)
def k_region(self, pos):
kr_size = self.k_region_size()
reg = math.floor(pos / kr_size)
return (kr_size * reg, kr_size * (reg + 1))
def k_region_size(self):
if len(self) == 0:
return 1.0
# Assume network knows log estimate of size
# and not actual size
n = float(pow(2, self.log))
# Get the size of a k-region
return self.two_above(self.k / n)
def remove(self, node):
self.remove_from_quorums(node)
self.nodes.remove(node.pos)
# Did we just shrink the network by a log size?
# If so, it's time to adjust quorum size
if len(self) == 0:
self.quorums = {}
elif int(math.log(len(self), 2)) < self.log:
self.log = int(math.log(len(self), 2))
self.redo_quorums()
def remove_from_quorums(self, node):
reg = self.quorum_region(node.pos)
self.quorums[reg].remove(node)
def add_to_quorums(self, node):
reg = self.quorum_region(node.pos)
self.quorums[reg].add(node)
def bootstrap_join(self, node):
node.pos = self.random_pos()
self.nodes.add(node.pos, node)
self.add_to_quorums(node)
# Did we just grow the network by a log size?
# If so, it's time to adjust quorum size
if math.floor(math.log(len(self), 2)) > self.log:
self.log = math.floor(math.log(len(self), 2))
self.redo_quorums()
def join(self, node, update_quorums=False):
# Pick a random location
rand = self.random_pos()
evict = self.k_region_nodes(rand)
# Reposition the other nodes in the k-region
for evicted in evict:
self.remove_from_quorums(evicted)
self.nodes.remove(evicted.pos)
# Secondary join (no evicting)
evicted.pos = self.random_pos()
self.nodes.add(evicted.pos, evicted)
self.add_to_quorums(evicted)
# Add the new node
node.pos = rand
self.add_to_quorums(node)
self.nodes.add(node.pos, node)
# Did we just grow the network by a log size?
# If so, it's time to adjust quorum size
if math.floor(math.log(len(self), 2)) > self.log:
self.log = math.floor(math.log(len(self), 2))
self.redo_quorums()
def quorum_size(self, pos):
reg = self.quorum_region(pos)
return len(self.quorums[reg])
def avg_quorum_size(self):
sum = 0.0
for q in self.quorums.itervalues():
sum += len(q)
return sum / len(self.quorums)
def quorum_region_size(self):
# gamma*log(n) k_regions
# where gamma is a small integer
if self.log == 0:
return 1.0
# Get the size of a k-region
g = float(self.gamma)
return self.two_above(self.k_region_size() * (g * self.log))
def quorum_region(self, pos):
q_size = self.quorum_region_size()
reg = math.floor(pos / q_size)
return (q_size * reg, q_size * (reg + 1))
def redo_quorums(self):
self.quorums = {}
q_size = self.quorum_region_size()
cur = 0.0
while cur < 1.0:
self.quorums[(cur, cur + q_size)] = set()
cur += q_size
for node in self.nodes:
r = self.quorum_region(node.pos)
self.quorums[r].add(node)
def verify(self):
# Verify each quorum region has no more than 1/4 byzantine
for quorum in self.quorums.itervalues():
bad = len([1 for n in quorum if n.byzantine])
if float(bad) / len(quorum) > 0.25:
return False
return True
def byzantine_from_least_faulty_quorum(self):
faultiness = {}
for (r, quorum) in self.quorums.iteritems():
bad = len([1 for n in quorum if n.byzantine])
faultiness[r] = float(bad) / len(quorum)
# Find the least faulty
least = (1.1, None)
for (r, fault) in faultiness.iteritems():
if fault < least[0] and fault > 0.0:
least = (fault, r)
least_q = self.quorums[least[1]]
# return the first byzantine node in this quorum
for node in least_q:
if node.byzantine:
return node
raise Exception("No node found")
