private void BroadCastClose(KademliaNode close, List <KademliaNode> nodes, int prefixLength)
{
if (!_alive)
{
return;
}
if (this != close)
{
int plength = CommonPrefixLength(_id, close._id);
_table[plength].Remove(close);
foreach (KademliaNode node in nodes)
{
Update(node);
}
}
KademliaNode target;
for (int i = prefixLength; i < k_TableSize; i++)
{
target = _table[i].GetRandomNode();
if (target == null)
{
continue;
}
target.BroadCastClose(close, nodes, i + 1);
}
}
private void SendNeighbours(KademliaNode remote, List <KademliaNode> neighbours)
{
// receive
List <KademliaNode> nodes = new List <KademliaNode>();
foreach (KademliaNode node in neighbours)
{
if (node != this && !IsInTable(node))
{
nodes.Add(node);
}
}
if (_find_request != -1)
{
nodes = SortByDistance(nodes, _find_request);
List <KademliaNode> closest_candidate = FindNeighbours(_find_request);
foreach (KademliaNode node in nodes)
{
node.Ping(this);
}
KademliaNode closest_known = closest_candidate.Count == 0 ? null : closest_candidate[0];
for (int i = 0; i < k_FindConcurrency && i < nodes.Count; i++)
{
if (closest_known is null || (nodes[i]._id ^ _find_request) < (closest_known._id ^ _find_request))
{
nodes[i].SendFindNode(this, _find_request);
}
}
}
}
private void SendFindNode(KademliaNode remote, int target_id)
{
Update(remote);
List <KademliaNode> found = FindNeighbours(target_id);
remote.SendNeighbours(this, found);
}
private void Transfer(KademliaNode remote, string msg, int prefixLength)
{
if (!_alive)
{
return;
}
if (this != remote)
{
Update(remote);
}
if (prefixLength != 0)
{
_touched = true;
_log.Add("Received : " + '"' + msg + '"');
_downloads++;
}
KademliaNode target;
for (int i = prefixLength; i < k_TableSize; i++)
{
target = _table[i].GetRandomNode();
if (target == null)
{
continue;
}
_log.Add("Transfer " + '"' + msg + '"' + " to Node " + target.GetId());
_uploads++;
target.Transfer(this, msg, i + 1);
}
}
public void Remove(KademliaNode node)
{
if (_contents.Contains(node))
{
_contents.Remove(node);
}
}
public bool Add(KademliaNode node)
{
if (_contents.Contains(node))
{
// move node to most recently used
_contents.Remove(node);
_contents.Add(node);
return(false);
}
if (_contents.Count < BucketSize)
{
_contents.Add(node);
return(true);
}
if (_contents.First().Respond())
{
// discard apped
return(false);
}
else
{
// evict least recently used node
_contents.RemoveAt(0);
_contents.Add(node);
return(true);
}
}
private void AddNeighbours(KademliaNode target, List <KademliaNode> neighbours, List <KademliaNode> querry)
{
KademliaNode[] closest = GetCloseNodes(target._id, querry);
for (int i = 0; i < k_FindConcurrency; i++)
{
if (closest[i] is null)
{
break;
}
querry.Add(closest[i]);
closest[i].AddNeighbours(target, neighbours, querry);
}
for (int i = 0; i < k_FindConcurrency; i++)
{
if (closest[i] is null || neighbours.Count > Bucket.BucketSize * 2)
{
break;
}
if (neighbours.Contains(closest[i]))
{
continue;
}
neighbours.Add(closest[i]);
}
AddNode(target);
}
private void Ping(KademliaNode remote)
{
if (_alive)
{
Update(remote);
}
// actually if node is dead, no respond and cause timeout exception
remote.Pong(this, _alive);
}
public void Update(KademliaNode node)
{
if (node.GetId() == _id)
{
return;
}
int plength = CommonPrefixLength(_id, node.GetId());
_table[plength].Update(node);
}
// Initial connect to bootstrap node
public void Bootstrap(KademliaNode bootstrapNode)
{
if (bootstrapNode is null)
{
return;
}
Update(bootstrapNode);
FindNode(_id, bootstrapNode);
}
private void Pong(KademliaNode remote, bool alive)
{
if (alive)
{
Update(remote);
}
else
{
RemoveNode(remote);
}
}
private bool IsInTable(KademliaNode node)
{
foreach (Bucket bucket in _table)
{
if (bucket._contents.Contains(node))
{
return(true);
}
}
return(false);
}
private void FindNode(int target_id, KademliaNode via_node = null)
{
_find_request = target_id;
if (via_node is null)
{
QuerryNeighbours(target_id);
}
else
{
via_node.SendFindNode(this, target_id);
}
_find_request = -1;
}
// Initial connect to bootstrap node
public void Connect(KademliaNode bootstrapNode)
{
if (bootstrapNode is null)
{
return;
}
AddNode(bootstrapNode);
foreach (KademliaNode node in bootstrapNode.FindNode(this))
{
AddNode(node);
}
}
private List <KademliaNode> FindNode(KademliaNode target)
{
List <KademliaNode> neighbours = new List <KademliaNode>();
AddNeighbours(target, neighbours, new List <KademliaNode>());
/*int index = 0;
* while (neighbours.Count < Bucket.BucketSize * 2 && index < neighbours.Count)
* neighbours[index++].AddNeighbours(target, neighbours);*/
/*for (index = 0; index < neighbours.Count; index++)
* neighbours[index].AddNeighbours(target, neighbours);*/
return(neighbours);
}
static public bool CreateKademliaNode(int id)
{
foreach (KademliaNode node in _kademliaNodes)
{
if (node.GetId() == id)
{
return(false);
}
}
KademliaNode newNode = new KademliaNode(id);
if (id != 0)
{
newNode.Bootstrap(_kademliaNodes[0]);
}
_kademliaNodes.Add(newNode);
return(true);
}
private KademliaNode[] GetCloseNodes(int target_id, List <KademliaNode> querry)
{
KademliaNode[] closeNodes = new KademliaNode[k_FindConcurrency];
for (int i = 0; i < k_TableSize; i++)
{
foreach (KademliaNode node in _table[i]._contents)
{
if (querry.Contains(node) ||
CommonPrefixLength(target_id, _id) > CommonPrefixLength(target_id, node._id) ||
CommonPrefixLength(target_id, node._id) == 32)
{
continue;
}
if (closeNodes[0] is null || CommonPrefixLength(target_id, node._id) >= CommonPrefixLength(target_id, closeNodes[0]._id))
{
closeNodes[2] = closeNodes[1];
closeNodes[1] = closeNodes[0];
closeNodes[0] = node;
}
private void BroadCastPing(KademliaNode remote, KademliaNode from, int prefixLength)
{
if (!_alive)
{
return;
}
KademliaNode target;
for (int i = prefixLength; i < k_TableSize; i++)
{
target = _table[i].GetRandomNode();
if (target == null || target == remote || target == from)
{
continue;
}
target.BroadCastPing(this, from, i + 1);
Update(from);
}
}
private List <KademliaNode> FindNeighbours(KademliaNode target, int k = Bucket.BucketSize)
{
return(FindNeighbours(target._id, k));
}
public void RemoveNode(KademliaNode node)
{
//int plength = CommonPrefixLength(_id, node.GetId());
}
public void RemoveNode(KademliaNode node)
{
int plength = CommonPrefixLength(_id, node.GetId());
_table[plength].Remove(node);
}
/// <summary>
/// Create a DHT using the given master server, and specify whether to publish our IP.
/// PRECONDITION: Create one per app or you will have a node ID collision.
/// </summary>
/// <param name="dhtNode">The KademliaNode that is used to communicate using the protocol</param>
/// <param name="alreadyBootstrapped">Checks if the node have or not to bootstrap</param>
/// <param name="btpNode">The node to bootstrap with (can be leaved null)</param>
public Dht(KademliaNode dhtNode = null, bool alreadyBootstrapped = false, string btpNode = "")
{
if (dhtNode != null)
{
this.dhtNode = dhtNode;
}
else
{
dhtNode = new KademliaNode();
}
if (!alreadyBootstrapped)
{
if (btpNode == "")
{
int ourPort = dhtNode.GetPort();
log.Info("We are on UDP port " + ourPort.ToString());
log.Info("Getting bootstrap list...");
AppSettingsReader asr = new AppSettingsReader();
XDocument xmlDoc = XDocument.Load((string)asr.GetValue("KademliaNodesFile", typeof(string)));
List <EndpointAddress> nodes = new List <EndpointAddress>(from node in xmlDoc.Descendants("Node")
select new EndpointAddress("soap.udp://" + node.Element("Host").Value + ":" + node.Element("Port").Value + "/kademlia"));
foreach (var node in nodes)
{
if (dhtNode.AsyncBootstrap(nodes))
{
log.Debug("OK!");
}
else
{
log.Debug("Failed.");
}
}
}
else
{
try
{
log.Debug("Bootstrapping with " + btpNode);
EndpointAddress bootstrapNode = new EndpointAddress(btpNode);
if (dhtNode.Bootstrap(bootstrapNode))
{
log.Debug("OK!");
}
else
{
log.Debug("Failed.");
}
}
catch (Exception ex)
{
log.Error("Bad entry!", ex);
}
}
}
else
{
log.Info("Self Bootstrapping");
dhtNode.Bootstrap();
}
// Join the network officially
log.Info("Trying to join network....");
if (dhtNode.JoinNetwork())
{
log.Info("Online");
}
else
{
log.Warn("Unable to connect to Kademlia overlay!\n"
+ "Check that nodes list has accessible nodes.");
}
}
