## Copyright 2002 Andrew Loewenstern, All Rights Reserved
-import hash
-from bisect import *
import time
+from bisect import *
from types import *
+import hash
import const
+from const import K, HASH_LENGTH
from node import Node
-# The all-powerful, magical Kademlia "k" constant, bucket depth
-K = 8
-
-# how many bits wide is our hash?
-HASH_LENGTH = 160
-
-
-# the local routing table for a kademlia like distributed hash table
class KTable:
+ """local routing table for a kademlia like distributed hash table"""
def __init__(self, node):
- # this is the root node, a.k.a. US!
- self.node = node
- self.buckets = [KBucket([], 0L, 2L**HASH_LENGTH)]
- self.insertNode(node)
-
+ # this is the root node, a.k.a. US!
+ self.node = node
+ self.buckets = [KBucket([], 0L, 2L**HASH_LENGTH)]
+ self.insertNode(node)
+
def _bucketIndexForInt(self, int):
- """returns the index of the bucket that should hold int"""
- return bisect_left(self.buckets, int)
+ """the index of the bucket that should hold int"""
+ return bisect_left(self.buckets, int)
def findNodes(self, id):
- """ return k nodes in our own local table closest to the ID
- ignoreSelf means we will return K closest nodes to ourself if we search for our own ID
- note, K closest nodes may actually include ourself, it's the callers responsibilty to
- not send messages to itself if it matters
- """
- if type(id) == StringType:
- int = hash.intify(id)
- elif type(id) == InstanceType:
- int = id.int
- elif type(id) == IntType or type(id) == LongType:
- int = id
- else:
- raise TypeError, "findLocalNodes requires an int, string, or Node instance type"
-
- nodes = []
-
- def sort(a, b, int=int):
- """ this function is for sorting nodes relative to the ID we are looking for """
- x, y = int ^ a.int, int ^ b.int
- if x > y:
- return 1
- elif x < y:
- return -1
- return 0
-
- i = self._bucketIndexForInt(int)
-
- ## see if this node is already in our table and return it
- try:
- index = self.buckets[i].l.index(int)
- except ValueError:
- pass
- else:
- return [self.buckets[i].l[index]]
-
- nodes = nodes + self.buckets[i].l
- if len(nodes) >= K:
- nodes.sort(sort)
- return nodes[:K]
- else:
- # need more nodes
- min = i - 1
- max = i + 1
- while (len(nodes) < K and (min >= 0 or max < len(self.buckets))):
- if min >= 0:
- nodes = nodes + self.buckets[min].l
- if max < len(self.buckets):
- nodes = nodes + self.buckets[max].l
- min = min - 1
- max = max + 1
- nodes.sort(sort)
- return nodes[:K]
-
+ """k nodes in our own local table closest to the ID.
+
+ NOTE: response may actually include ourself, it's your responsibilty
+ to not send messages to yourself if it matters."""
+
+ if isinstance(id, str):
+ int = hash.intify(id)
+ elif isinstance(id, Node):
+ int = id.int
+ elif isinstance(id, int) or isinstance(id, long):
+ int = id
+ else:
+ raise TypeError, "findNodes requires an int, string, or Node"
+
+ nodes = []
+ i = self._bucketIndexForInt(int)
+
+ # if this node is already in our table then return it
+ if int in self.buckets[i].l.index(int): return [int]
+
+ nodes = nodes + self.buckets[i].l
+ if len(nodes) < K:
+ # need more nodes
+ min = i - 1
+ max = i + 1
+ while len(nodes) < K and (min >= 0 or max < len(self.buckets)):
+ #ASw: note that this requires K be even
+ if min >= 0:
+ nodes = nodes + self.buckets[min].l
+ if max < len(self.buckets):
+ nodes = nodes + self.buckets[max].l
+ min = min - 1
+ max = max + 1
+
+ nodes.sort(lambda a, b, int=int: cmp(int ^ a.int, int ^ b.int))
+ return nodes[:K]
+
def _splitBucket(self, a):
- diff = (a.max - a.min) / 2
- b = KBucket([], a.max - diff, a.max)
- self.buckets.insert(self.buckets.index(a.min) + 1, b)
- a.max = a.max - diff
- # transfer nodes to new bucket
- for anode in a.l[:]:
- if anode.int >= a.max:
- a.l.remove(anode)
- b.l.append(anode)
+ diff = (a.max - a.min) / 2
+ b = KBucket([], a.max - diff, a.max)
+ self.buckets.insert(self.buckets.index(a.min) + 1, b)
+ a.max = a.max - diff
+ # transfer nodes to new bucket
+ for anode in a.l[:]:
+ if anode.int >= a.max:
+ a.l.remove(anode)
+ b.l.append(anode)
def replaceStaleNode(self, stale, new):
- """ this is used by clients to replace a node returned by insertNode after
- it fails to respond to a Pong message
- """
- i = self._bucketIndexForInt(stale.int)
- try:
- it = self.buckets[i].l.index(stale.int)
- except ValueError:
- return
-
- del(self.buckets[i].l[it])
- if new:
- self.buckets[i].l.append(new)
+ """this is used by clients to replace a node returned by insertNode after
+ it fails to respond to a Pong message"""
+ i = self._bucketIndexForInt(stale.int)
+ try:
+ it = self.buckets[i].l.index(stale.int)
+ except ValueError:
+ return
+
+ del(self.buckets[i].l[it])
+ if new:
+ self.buckets[i].l.append(new)
def insertNode(self, node, contacted=1):
- """
- this insert the node, returning None if successful, returns the oldest node in the bucket if it's full
- the caller responsible for pinging the returned node and calling replaceStaleNode if it is found to be stale!!
- contacted means that yes, we contacted THEM and we know the node is available
- """
- assert(node.id != " "*20)
- if node.id == self.node.id:
- return
- # get the bucket for this node
- i = self. _bucketIndexForInt(node.int)
- ## check to see if node is in the bucket already
- try:
- it = self.buckets[i].l.index(node.int)
- except ValueError:
- ## no
- pass
- else:
- if contacted:
- node.updateLastSeen()
- # move node to end of bucket
- xnode = self.buckets[i].l[it]
- del(self.buckets[i].l[it])
- # note that we removed the original and replaced it with the new one
- # utilizing this nodes new contact info
- self.buckets[i].l.append(xnode)
- self.buckets[i].touch()
- return
-
- # we don't have this node, check to see if the bucket is full
- if len(self.buckets[i].l) < K:
- # no, append this node and return
- if contacted:
- node.updateLastSeen()
- self.buckets[i].l.append(node)
- self.buckets[i].touch()
- return
-
- # bucket is full, check to see if self.node is in the bucket
- if not (self.buckets[i].min <= self.node < self.buckets[i].max):
- return self.buckets[i].l[0]
-
- ## this bucket is full and contains our node, split the bucket
- if len(self.buckets) >= HASH_LENGTH:
- # our table is FULL
- print "Hash Table is FULL! Increase K!"
- return
-
- self._splitBucket(self.buckets[i])
-
- ## now that the bucket is split and balanced, try to insert the node again
- return self.insertNode(node)
+ """
+ this insert the node, returning None if successful, returns the oldest node in the bucket if it's full
+ the caller responsible for pinging the returned node and calling replaceStaleNode if it is found to be stale!!
+ contacted means that yes, we contacted THEM and we know the node is available
+ """
+ assert node.id != " "*20
+ if node.id == self.node.id: return
+ # get the bucket for this node
+ i = self. _bucketIndexForInt(node.int)
+ # check to see if node is in the bucket already
+ try:
+ it = self.buckets[i].l.index(node.int)
+ except ValueError:
+ # no
+ pass
+ else:
+ if contacted:
+ node.updateLastSeen()
+ # move node to end of bucket
+ xnode = self.buckets[i].l[it]
+ del(self.buckets[i].l[it])
+ # note that we removed the original and replaced it with the new one
+ # utilizing this nodes new contact info
+ self.buckets[i].l.append(xnode)
+ self.buckets[i].touch()
+ return
+
+ # we don't have this node, check to see if the bucket is full
+ if len(self.buckets[i].l) < K:
+ # no, append this node and return
+ if contacted:
+ node.updateLastSeen()
+ self.buckets[i].l.append(node)
+ self.buckets[i].touch()
+ return
+
+ # bucket is full, check to see if self.node is in the bucket
+ if not (self.buckets[i].min <= self.node < self.buckets[i].max):
+ return self.buckets[i].l[0]
+
+ # this bucket is full and contains our node, split the bucket
+ if len(self.buckets) >= HASH_LENGTH:
+ # our table is FULL, this is really unlikely
+ print "Hash Table is FULL! Increase K!"
+ return
+
+ self._splitBucket(self.buckets[i])
+
+ # now that the bucket is split and balanced, try to insert the node again
+ return self.insertNode(node)
def justSeenNode(self, node):
- """ call this any time you get a message from a node, to update it in the table if it's there """
- try:
- n = self.findNodes(node.int)[0]
- except IndexError:
- return None
- else:
- tstamp = n.lastSeen
- n.updateLastSeen()
- return tstamp
+ """call this any time you get a message from a node
+ it will update it in the table if it's there """
+ try:
+ n = self.findNodes(node.int)[0]
+ except IndexError:
+ return None
+ else:
+ tstamp = n.lastSeen
+ n.updateLastSeen()
+ return tstamp
def nodeFailed(self, node):
- """ call this when a node fails to respond to a message, to invalidate that node """
- try:
- n = self.findNodes(node.int)[0]
- except IndexError:
- return None
- else:
- if(n.msgFailed() >= const.MAX_FAILURES):
- self.replaceStaleNode(n, None)
-
+ """ call this when a node fails to respond to a message, to invalidate that node """
+ try:
+ n = self.findNodes(node.int)[0]
+ except IndexError:
+ return None
+ else:
+ if n.msgFailed() >= const.MAX_FAILURES:
+ self.replaceStaleNode(n, None)
+
class KBucket:
__slots = ['min', 'max', 'lastAccessed']
def __init__(self, contents, min, max):
- self.l = contents
- self.min = min
- self.max = max
- self.lastAccessed = time.time()
-
+ self.l = contents
+ self.min = min
+ self.max = max
+ self.lastAccessed = time.time()
+
def touch(self):
- self.lastAccessed = time.time()
+ self.lastAccessed = time.time()
def getNodeWithInt(self, int):
- try:
- return self.l[self.l.index(int)]
- except IndexError:
- raise ValueError
-
+ if int in self.l: return int
+ else: raise ValueError
+
def __repr__(self):
- return "<KBucket items: %d min: %d\tmax: %d>" % (len(self.l), self.min, self.max)
-
- ## comparators, necessary for bisecting list of buckets with a hash expressed as an integer or a distance
- ## compares integer or node object with the bucket's range
+ return "<KBucket %d items (%d to %d)>" % (len(self.l), self.min, self.max)
+
+ ## Comparators
+ # necessary for bisecting list of buckets with a hash expressed as an integer or a distance
+ # compares integer or node object with the bucket's range
def __lt__(self, a):
- if type(a) == InstanceType:
- a = a.int
- return self.max <= a
+ if isinstance(a, Node): a = a.int
+ return self.max <= a
def __le__(self, a):
- if type(a) == InstanceType:
- a = a.int
- return self.min < a
+ if isinstance(a, Node): a = a.int
+ return self.min < a
def __gt__(self, a):
- if type(a) == InstanceType:
- a = a.int
- return self.min > a
+ if isinstance(a, Node): a = a.int
+ return self.min > a
def __ge__(self, a):
- if type(a) == InstanceType:
- a = a.int
- return self.max >= a
+ if isinstance(a, Node): a = a.int
+ return self.max >= a
def __eq__(self, a):
- if type(a) == InstanceType:
- a = a.int
- return self.min <= a and self.max > a
+ if isinstance(a, Node): a = a.int
+ return self.min <= a and self.max > a
def __ne__(self, a):
- if type(a) == InstanceType:
- a = a.int
- return self.min >= a or self.max < a
-
+ if isinstance(a, Node): a = a.int
+ return self.min >= a or self.max < a
-##############
+### UNIT TESTS ###
import unittest
class TestKTable(unittest.TestCase):
def setUp(self):
- self.a = Node().init(hash.newID(), 'localhost', 2002)
- self.t = KTable(self.a)
+ self.a = Node().init(hash.newID(), 'localhost', 2002)
+ self.t = KTable(self.a)
+ print self.t.buckets[0].l
def test_replace_stale_node(self):
- self.b = Node().init(hash.newID(), 'localhost', 2003)
- self.t.replaceStaleNode(self.a, self.b)
- assert(len(self.t.buckets[0].l) == 1)
- assert(self.t.buckets[0].l[0].id == self.b.id)
+ self.b = Node().init(hash.newID(), 'localhost', 2003)
+ self.t.replaceStaleNode(self.a, self.b)
+ assert len(self.t.buckets[0].l) == 1
+ assert self.t.buckets[0].l[0].id == self.b.id
if __name__ == "__main__":
- unittest.main()
\ No newline at end of file
+ unittest.main()
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