Kademlia Contact Removal

- Contact removal now working well, we only do removal when we need to get in touch with the contact for some reason.
- Replacement cache is now setup
This commit is contained in:
Joshua Kissoon 2014-04-28 20:38:47 +05:30
parent fa47aceda9
commit b1bfba6d93
6 changed files with 160 additions and 83 deletions

View File

@ -284,9 +284,9 @@ public class ContentLookupOperation implements Operation, Receiver
throw new UnknownMessageException("Unknown comm: " + comm);
}
/* Mark this node as failed */
/* Mark this node as failed and inform the routing table that it's unresponsive */
this.nodes.put(n, FAILED);
this.localNode.getRoutingTable().remove(n);
this.localNode.getRoutingTable().setUnresponsiveContact(n);
this.messagesTransiting.remove(comm);
this.askNodesorFinish();

View File

@ -303,9 +303,9 @@ public class NodeLookupOperation implements Operation, Receiver
throw new UnknownMessageException("Unknown comm: " + comm);
}
/* Mark this node as failed */
/* Mark this node as failed and inform the routing table that it is unresponsive */
this.nodes.put(n, FAILED);
this.localNode.getRoutingTable().remove(n);
this.localNode.getRoutingTable().setUnresponsiveContact(n);
this.messagesTransiting.remove(comm);
this.askNodesorFinish();

View File

@ -48,15 +48,19 @@ public interface Bucket
* Remove a contact from this bucket
*
* @param c The contact to remove
*
* @return Boolean whether the removal was successful.
*/
public void removeContact(Contact c);
public boolean removeContact(Contact c);
/**
* Remove the contact object related to a node from this bucket
*
* @param n The node of the contact to remove
*
* @return Boolean whether the removal was successful.
*/
public void removeNode(Node n);
public boolean removeNode(Node n);
/**
* Counts the number of contacts in this bucket.

View File

@ -2,8 +2,8 @@ package kademlia.routing;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import kademlia.core.KadConfiguration;
import kademlia.node.Node;
/**
@ -19,10 +19,12 @@ public class KadBucket implements Bucket
private final int depth;
/* Contacts stored in this routing table */
private final Map<Contact, Contact> contacts;
private final TreeMap<Contact, Contact> contacts;
/* A set of last seen contacts that can replace any current contact that is unresponsive */
private final Map<Contact, Contact> replacementCache;
private final TreeMap<Contact, Contact> replacementCache;
private KadConfiguration config;
{
@ -32,16 +34,17 @@ public class KadBucket implements Bucket
/**
* @param depth How deep in the routing tree is this bucket
* @param config
*/
public KadBucket(int depth)
public KadBucket(int depth, KadConfiguration config)
{
this.depth = depth;
this.config = config;
}
@Override
public void insert(Contact c)
{
/* @todo Check if the bucket is filled already and handle the situation */
if (this.contacts.containsKey(c))
{
/**
@ -53,10 +56,19 @@ public class KadBucket implements Bucket
this.contacts.put(tmp, tmp);
}
else
{
/* If the bucket is filled, we put the contacts in the replacement cache */
if (contacts.size() >= this.config.k())
{
/* Bucket is filled, place this contact in the replacement cache */
this.insertIntoCache(c);
}
else
{
contacts.put(c, c);
}
}
}
@Override
public void insert(Node n)
@ -77,15 +89,31 @@ public class KadBucket implements Bucket
}
@Override
public void removeContact(Contact c)
public boolean removeContact(Contact c)
{
/* If the contact does not exist, then we failed to remove it */
if (!this.contacts.containsKey(c))
{
return false;
}
this.contacts.remove(c);
/* If there are replacement contacts in the replacement cache, lets put them into the bucket */
if (!this.replacementCache.isEmpty())
{
Contact replacement = this.replacementCache.firstKey();
this.contacts.put(replacement, replacement);
this.replacementCache.remove(replacement);
}
return true;
}
@Override
public void removeNode(Node n)
public boolean removeNode(Node n)
{
this.removeContact(new Contact(n));
return this.removeContact(new Contact(n));
}
@Override
@ -106,6 +134,26 @@ public class KadBucket implements Bucket
return (this.contacts.isEmpty()) ? new ArrayList<>() : new ArrayList<>(this.contacts.values());
}
/**
* When the bucket is filled, we keep extra contacts in the replacement cache.
*/
private void insertIntoCache(Contact c)
{
/* Just return if this contact is already in our replacement cache */
if (this.replacementCache.containsKey(c))
{
return;
}
/* if our cache is filled, we remove the least recently seen contact */
if (this.replacementCache.size() > this.config.k())
{
this.replacementCache.remove(this.replacementCache.lastKey());
}
this.replacementCache.put(c, c);
}
@Override
public String toString()
{

View File

@ -40,7 +40,7 @@ public class RoutingTable
this.buckets = new Bucket[NodeId.ID_LENGTH];
for (int i = 0; i < NodeId.ID_LENGTH; i++)
{
buckets[i] = new KadBucket(i);
buckets[i] = new KadBucket(i, this.config);
}
}
@ -64,22 +64,6 @@ public class RoutingTable
this.buckets[this.getBucketId(n.getNodeId())].insert(n);
}
/**
* Remove a node from the routing table.
*
* @param n The node to remove
*/
public final void remove(Node n)
{
int bucketId = this.getBucketId(n.getNodeId());
/* If the bucket has the contact, remove it */
if (this.buckets[bucketId].containsNode(n))
{
this.buckets[bucketId].removeNode(n);
}
}
/**
* Compute the bucket ID in which a given node should be placed; the bucketId is computed based on how far the node is away from the Local Node.
*
@ -247,14 +231,27 @@ public class RoutingTable
{
return;
}
System.out.println("Unresponsive contacts: ");
for (Node n : contacts)
{
System.out.println(n);
this.setUnresponsiveContact(n);
}
}
/**
* Method used by operations to notify the routing table of any contacts that have been unresponsive.
*
* @param n
*/
public synchronized void setUnresponsiveContact(Node n)
{
int bucketId = this.getBucketId(n.getNodeId());
//System.out.println(this.localNode + " Removing unresponsive node " + n);
/* Remove the contact from the bucket */
this.buckets[bucketId].removeNode(n);
}
@Override
public synchronized final String toString()
{

View File

@ -1,6 +1,7 @@
package kademlia.tests;
import java.io.IOException;
import java.util.Scanner;
import kademlia.KademliaNode;
import kademlia.dht.KadContent;
import kademlia.node.NodeId;
@ -14,33 +15,32 @@ import kademlia.node.NodeId;
public class RoutingTableStateTesting
{
KademliaNode kad0, kad1, kad2, kad3, kad4, kad5, kad6, kad7, kad8, kad9;
KademliaNode[] kads;
public int numKads = 10;
public RoutingTableStateTesting()
{
try
{
/* Setting up 2 Kad networks */
kad0 = new KademliaNode("user0", new NodeId("HRF456789SD584567460"), 1334);
kad1 = new KademliaNode("user1", new NodeId("ASF456789475DS567461"), 1209);
kad2 = new KademliaNode("user2", new NodeId("AFG45678947584567462"), 4585);
kad3 = new KademliaNode("user3", new NodeId("FSF45J38947584567463"), 8104);
kad4 = new KademliaNode("user4", new NodeId("ASF45678947584567464"), 8335);
kad5 = new KademliaNode("user5", new NodeId("GHF4567894DR84567465"), 13345);
kad6 = new KademliaNode("user6", new NodeId("ASF45678947584567466"), 12049);
kad7 = new KademliaNode("user7", new NodeId("AE345678947584567467"), 14585);
kad8 = new KademliaNode("user8", new NodeId("ASAA5678947584567468"), 18104);
kad9 = new KademliaNode("user9", new NodeId("ASF456789475845674U9"), 18335);
/* Setting up Kad networks */
kads = new KademliaNode[numKads];
kad1.bootstrap(kad0.getNode());
kad2.bootstrap(kad0.getNode());
kad3.bootstrap(kad0.getNode());
kad4.bootstrap(kad0.getNode());
kad5.bootstrap(kad0.getNode());
kad6.bootstrap(kad0.getNode());
kad7.bootstrap(kad0.getNode());
kad8.bootstrap(kad0.getNode());
kad9.bootstrap(kad0.getNode());
kads[0] = new KademliaNode("user0", new NodeId("HRF456789SD584567460"), 1334);
kads[1] = new KademliaNode("user1", new NodeId("ASF456789475DS567461"), 1209);
kads[2] = new KademliaNode("user2", new NodeId("AFG45678947584567462"), 4585);
kads[3] = new KademliaNode("user3", new NodeId("FSF45J38947584567463"), 8104);
kads[4] = new KademliaNode("user4", new NodeId("ASF45678947584567464"), 8335);
kads[5] = new KademliaNode("user5", new NodeId("GHF4567894DR84567465"), 13345);
kads[6] = new KademliaNode("user6", new NodeId("ASF45678947584567466"), 12049);
kads[7] = new KademliaNode("user7", new NodeId("AE345678947584567467"), 14585);
kads[8] = new KademliaNode("user8", new NodeId("ASAA5678947584567468"), 18104);
kads[9] = new KademliaNode("user9", new NodeId("ASF456789475845674U9"), 18335);
for (int i = 1; i < numKads; i++)
{
kads[i].bootstrap(kads[0].getNode());
}
/* Lets shut down a node and then try putting a content on the network. We'll then see how the un-responsive contacts work */
}
@ -55,7 +55,7 @@ public class RoutingTableStateTesting
DHTContentImpl c = null;
try
{
c = new DHTContentImpl(kad2.getOwnerId(), "Some Data");
c = new DHTContentImpl(owner.getOwnerId(), "Some Data");
owner.put(c);
return c;
}
@ -79,43 +79,71 @@ public class RoutingTableStateTesting
}
}
public void printRoutingTable(int kadId)
{
System.out.println(kads[kadId].getRoutingTable());
}
public void printRoutingTables()
{
System.out.println(kad0.getRoutingTable());
System.out.println(kad1.getRoutingTable());
System.out.println(kad2.getRoutingTable());
System.out.println(kad3.getRoutingTable());
System.out.println(kad4.getRoutingTable());
System.out.println(kad5.getRoutingTable());
System.out.println(kad6.getRoutingTable());
System.out.println(kad7.getRoutingTable());
System.out.println(kad8.getRoutingTable());
System.out.println(kad9.getRoutingTable());
for (int i = 0; i < numKads; i++)
{
this.printRoutingTable(i);
}
}
public void printStorage(int kadId)
{
System.out.println(kads[kadId].getDHT());
}
public void printStorage()
{
System.out.println(kad0.getDHT());
System.out.println(kad1.getDHT());
System.out.println(kad2.getDHT());
System.out.println(kad3.getDHT());
System.out.println(kad4.getDHT());
System.out.println(kad5.getDHT());
System.out.println(kad6.getDHT());
System.out.println(kad7.getDHT());
System.out.println(kad8.getDHT());
System.out.println(kad9.getDHT());
for (int i = 0; i < numKads; i++)
{
this.printStorage(i);
}
}
public static void main(String[] args)
{
RoutingTableStateTesting rtss = new RoutingTableStateTesting();
try
{
rtss.printRoutingTables();
/* Lets shut down a node to test the node removal operation */
rtss.shutdownKad(rtss.kad3);
rtss.shutdownKad(rtss.kads[3]);
rtss.putContent("Content owned by kad0", rtss.kad0);
rtss.putContent("Content owned by kad0", rtss.kads[0]);
rtss.printStorage();
Thread.sleep(1000);
/* kad3 should be removed from their routing tables by now. */
rtss.printRoutingTables();
}
catch (InterruptedException ex)
{
}
Scanner sc = new Scanner(System.in);
while (true)
{
System.out.println("\n\n ************************* Options **************************** \n");
System.out.println("1 i - Print routing table of node i");
int val1 = sc.nextInt();
int val2 = sc.nextInt();
switch (val1)
{
case 1:
rtss.printRoutingTable(val2);
break;
}
}
}
}