+++ /dev/null
-## Copyright 2002-2003 Andrew Loewenstern, All Rights Reserved
-# see LICENSE.txt for license information
-
-from time import time
-from bisect import bisect_left
-
-from const import K, HASH_LENGTH, NULL_ID, MAX_FAILURES
-import khash
-from node import Node
-
-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)
-
- def _bucketIndexForInt(self, num):
- """the index of the bucket that should hold int"""
- return bisect_left(self.buckets, num)
-
- def findNodes(self, id):
- """
- return K nodes in our own local table closest to the ID.
- """
-
- if isinstance(id, str):
- num = khash.intify(id)
- elif isinstance(id, Node):
- num = id.num
- elif isinstance(id, int) or isinstance(id, long):
- num = id
- else:
- raise TypeError, "findNodes requires an int, string, or Node"
-
- nodes = []
- i = self._bucketIndexForInt(num)
-
- # if this node is already in our table then return it
- try:
- index = self.buckets[i].l.index(num)
- except ValueError:
- pass
- else:
- return [self.buckets[i].l[index]]
-
- # don't have the node, get the K closest nodes
- 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, num=num: cmp(num ^ a.num, num ^ b.num))
- 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.num >= 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.num)
- try:
- it = self.buckets[i].l.index(stale.num)
- 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 reachable
- """
- assert node.id != NULL_ID
- if node.id == self.node.id: return
- # get the bucket for this node
- i = self. _bucketIndexForInt(node.num)
- # check to see if node is in the bucket already
- try:
- it = self.buckets[i].l.index(node.num)
- 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, id):
- """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(id)[0]
- except IndexError:
- return None
- else:
- tstamp = n.lastSeen
- n.updateLastSeen()
- return tstamp
-
- def invalidateNode(self, n):
- """
- forget about node n - use when you know that node is invalid
- """
- self.replaceStaleNode(n, None)
-
- def nodeFailed(self, node):
- """ call this when a node fails to respond to a message, to invalidate that node """
- try:
- n = self.findNodes(node.num)[0]
- except IndexError:
- return None
- else:
- if n.msgFailed() >= MAX_FAILURES:
- self.invalidateNode(n)
-
-class KBucket:
- def __init__(self, contents, min, max):
- self.l = contents
- self.min = min
- self.max = max
- self.lastAccessed = time()
-
- def touch(self):
- self.lastAccessed = time()
-
- def getNodeWithInt(self, num):
- if num in self.l: return num
- else: raise ValueError
-
- def __repr__(self):
- 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 isinstance(a, Node): a = a.num
- return self.max <= a
- def __le__(self, a):
- if isinstance(a, Node): a = a.num
- return self.min < a
- def __gt__(self, a):
- if isinstance(a, Node): a = a.num
- return self.min > a
- def __ge__(self, a):
- if isinstance(a, Node): a = a.num
- return self.max >= a
- def __eq__(self, a):
- if isinstance(a, Node): a = a.num
- return self.min <= a and self.max > a
- def __ne__(self, a):
- if isinstance(a, Node): a = a.num
- return self.min >= a or self.max < a
-
-
-### UNIT TESTS ###
-import unittest
-
-class TestKTable(unittest.TestCase):
- def setUp(self):
- self.a = Node().init(khash.newID(), 'localhost', 2002)
- self.t = KTable(self.a)
-
- def testAddNode(self):
- self.b = Node().init(khash.newID(), 'localhost', 2003)
- self.t.insertNode(self.b)
- self.assertEqual(len(self.t.buckets[0].l), 1)
- self.assertEqual(self.t.buckets[0].l[0], self.b)
-
- def testRemove(self):
- self.testAddNode()
- self.t.invalidateNode(self.b)
- self.assertEqual(len(self.t.buckets[0].l), 0)
-
- def testFail(self):
- self.testAddNode()
- for i in range(MAX_FAILURES - 1):
- self.t.nodeFailed(self.b)
- self.assertEqual(len(self.t.buckets[0].l), 1)
- self.assertEqual(self.t.buckets[0].l[0], self.b)
-
- self.t.nodeFailed(self.b)
- self.assertEqual(len(self.t.buckets[0].l), 0)
-
-
-if __name__ == "__main__":
- unittest.main()
projects / quix0rs-apt-p2p.git / blobdiff