public KadValue FindValue(KadId valueId)
{
if (Owner.Storage.Contains(valueId))
{
var storageVal = Owner.Storage.Get(valueId);
if (Owner.IsValueExpired(storageVal))
{
Owner.Storage.Remove(valueId);
}
else
{
return(storageVal);
}
}
SortedSet <KadContactNode> shortList;
Tuple <KadContactNode, KadValue> value = LookupValue(valueId, out shortList);
if (value != null)
{
if (shortList.Min.Id != value.Item1.Id)
{
Owner.StoreValue(shortList.Min, value.Item2);
}
Owner.Storage.Put(value.Item2);
}
return(value.Item2);
}
private Tuple <KadContactNode, KadValue> LookupValue(KadId valueId, out SortedSet <KadContactNode> retSortList)
{
var closestNodes = Owner.BucketList.GetClosestNodes(valueId, MaxConcurrentThreads);
SortedSet <KadContactNode> shortList = new SortedSet <KadContactNode>(closestNodes, new KadId.KadIdToBaseComparator(valueId));
retSortList = shortList;
if (shortList.Count == 0)
{
return(null);
}
SortedSet <KadId> queriedNodes = new SortedSet <KadId>(new KadId.KadIdToIdComparator());
KadId closestId = shortList.Min.Id;
SemaphoreSlim tasksSemaphore = new SemaphoreSlim(MaxConcurrentThreads);
KadContactNode returnedNode = null;
KadValue value = null;
//Should do fine for small alpha
List <Task> tasks = new List <Task>();
while (queriedNodes.Count < ReplicationCount)
{
var shortListSnapshot = shortList.Where((n) => !queriedNodes.Contains(n.Id)).ToList();
foreach (var node in shortListSnapshot)
{
tasks.Add(Task.Run(() => {
var response = Owner.FindValue(node, valueId);
if (response != null)
{
if (response.Type == MessageType.FindNode)
{
foreach (var contact in response.Contacts)
{
shortList.Add(contact);
}
}
else if (response.Type == MessageType.FindValue)
{
value = new KadValue(valueId, DateTime.Now, response.Payload);
returnedNode = node;
}
}
tasksSemaphore.Release();
}));
queriedNodes.Add(node.Id);
tasksSemaphore.Wait();
}
Task.WaitAll(tasks.ToArray());
tasks.Clear();
if ((shortList.Min.Id ^ closestId) >= closestId)
{
break;
}
closestId = shortList.Min.Id;
}
return(value != null ? new Tuple <KadContactNode, KadValue>(returnedNode, value) : null);
}
/// <summary>
/// Retrives value from other node
/// </summary>
/// <param name="node">Node to query</param>
/// <param name="valId">Value id</param>
/// <returns>Value if queried node has value, otherwise closest nodes to id</returns>
public NodeMessage FindValue(KadContactNode node, KadId valId)
{
NodeMessage findValMsg = new NodeMessage.Builder()
.SetType(MessageType.FindValue)
.SetOriginator(Id)
.SetIsRequest(true)
.SetPayload(valId.Value)
.Build();
findValMsg.AddCallback(UpdateLastSeen);
return(_server.SendMessageSync(node.EndPoint, findValMsg, TimeoutInMSec).Response);
}
private IEnumerable <KadContactNode> LookupNode(KadId nodeId)
{
var closestNodes = Owner.BucketList.GetClosestNodes(nodeId, MaxConcurrentThreads);
SortedSet <KadContactNode> shortList = new SortedSet <KadContactNode>(closestNodes, new KadId.KadIdToBaseComparator(nodeId));
if (shortList.Count == 0)
{
return(shortList);
}
SortedSet <KadId> queriedNodes = new SortedSet <KadId>(new KadId.KadIdToIdComparator());
KadId closestId = shortList.Min.Id;
SemaphoreSlim tasksSemaphore = new SemaphoreSlim(MaxConcurrentThreads);
List <Task> tasks = new List <Task>();
while (queriedNodes.Count < ReplicationCount)
{
var shortListSnapshot = shortList.Where((n) => !queriedNodes.Contains(n.Id)).ToList();
foreach (var node in shortListSnapshot)
{
tasks.Add(Task.Run(() => {
var contacts = Owner.FindNode(node, nodeId);
foreach (var contact in contacts)
{
shortList.Add(contact);
}
tasksSemaphore.Release();
}));
tasksSemaphore.Wait();
}
Task.WaitAll(tasks.ToArray());
tasks.Clear();
if ((shortList.Min.Id ^ closestId) >= closestId)
{
break;
}
closestId = shortList.Min.Id;
}
return(shortList.Take(ReplicationCount).ToList());
}
public void RefreshBucket(KadId id)
{
var closestNodes = LookupNode(id);
foreach (var contactNode in closestNodes)
{
switch (Owner.BucketList.Put(contactNode))
{
case Buckets.BucketList.BucketPutResult.BucketIsFull:
TryReplaceLeastSeenContactFromBucket(contactNode);
break;
case Buckets.BucketList.BucketPutResult.Updated:
case Buckets.BucketList.BucketPutResult.Success:
//Nothing to do here.
break;
}
}
}
/// <summary>
/// Find contact's closest nodes to id
/// </summary>
/// <param name="node">Node to query</param>
/// <param name="id">Id to compare</param>
/// <returns>Closest nodes to id</returns>
public IEnumerable <KadContactNode> FindNode(KadContactNode node, KadId id)
{
NodeMessage msg = new NodeMessage.Builder()
.SetType(MessageType.FindNode)
.SetOriginator(Id)
.SetIsRequest(true)
.SetPayload(id.Value)
.Build();
NodeMessage response = _server.SendMessageSync(node.EndPoint, msg, TimeoutInMSec).Response;
msg.AddCallback(UpdateLastSeen);
if (response != null)
{
return(new List <KadContactNode>(response.Contacts));
}
return(new List <KadContactNode>());
}
public void RefreshUnaccessedBuckets()
{
SortedSet <Buckets.Bucket> sortedBuckets = new SortedSet <Buckets.Bucket>(Owner.BucketList.Buckets, new Buckets.Bucket.ByLastUpdatedComparer());
foreach (var bucket in sortedBuckets)
{
if ((DateTime.UtcNow - bucket.LastUpdated).TotalSeconds > BucketsRefreshInSecs)
{
byte[] intBytes = BitConverter.GetBytes(bucket.Id);
byte[] idBytes = new byte[ReplicationCount];
Buffer.BlockCopy(intBytes, 0, idBytes, 0, intBytes.Length);
KadId bucketId = new KadId(idBytes);
RefreshBucket(bucketId);
}
else
{
break;
}
}
}
public KadContactNode(KadId id, IPEndPoint endPoint)
{
Id = id;
EndPoint = endPoint;
}
/// <summary>
/// Pings other node
/// </summary>
/// <param name="id">Node id to ping</param>
/// <returns></returns>
public NodeMessage Ping(KadId id)
{
var bucket = BucketList.GetBucket(id);
return(Ping(bucket.GetNode(id)));
}
public KadNode(IPEndPoint ipEndpoint, KadId id)
{
Id = id;
InitNode(ipEndpoint);
}
public KadNode(IPEndPoint ipEndpoint)
{
Id = KadId.GenerateRandom();
InitNode(ipEndpoint);
}
/// <summary>
/// Processes request from other node. Used by NodeServer class
/// </summary>
/// <param name="msg">Request to process</param>
/// <param name="origAddress">Request originator adress</param>
public void ProcessRequest(NodeMessage msg, IPEndPoint origAddress)
{
switch (msg.Type)
{
case MessageType.Ping: { //TODO: handle cases when bucket is full, etc
NodeMessage respMsg = new NodeMessage.Builder()
.SetType(MessageType.Ping)
.SetOriginator(Id)
.SetSeq(msg.Seq)
.SetIsRequest(false)
.Build();
_server.SendMessage(origAddress, respMsg);
break;
}
case MessageType.FindNode: {
var closestNodes = BucketList.GetClosestNodes(new KadId(msg.Payload), 20);
NodeMessage respMsg = new NodeMessage.Builder()
.SetType(MessageType.FindNode)
.SetSeq(msg.Seq)
.SetOriginator(Id)
.SetContacts(closestNodes)
.Build();
_server.SendMessage(origAddress, respMsg);
break;
}
case MessageType.FindValue: {
KadId valueId = new KadId(msg.Payload);
NodeMessage.Builder msgBuilder = new NodeMessage.Builder()
.SetType(MessageType.FindValue)
.SetSeq(msg.Seq)
.SetOriginator(Id);
if (Storage.Contains(valueId))
{
msgBuilder.SetKadValueAsPayload(Storage.Get(valueId));
}
else
{
var closestNodes = BucketList.GetClosestNodes(valueId, 20);
msgBuilder.SetContacts(closestNodes)
.SetType(MessageType.FindNode);
}
_server.SendMessage(origAddress, msgBuilder.Build());
break;
}
case MessageType.CanStoreValue: {
NodeMessage respMsg = new NodeMessage.Builder()
.SetType(MessageType.CanStoreValue)
.SetSeq(msg.Seq)
.SetOriginator(Id)
.SetIsRequest(false)
.SetFlagAsPayload(!Storage.IsFull())
.Build();
_server.SendMessage(origAddress, respMsg);
break;
}
case MessageType.StoreValue: {
NodeMessage.Builder msgBuilder = new NodeMessage.Builder()
.SetSeq(msg.Seq)
.SetOriginator(Id)
.SetIsRequest(false)
.SetType(MessageType.CanStoreValue);
if (Storage.IsFull())
{
msgBuilder.SetFlagAsPayload(false);
}
else
{
msgBuilder.SetFlagAsPayload(true);
Storage.Put(msg.Value);
}
_server.SendMessage(origAddress, msgBuilder.Build());
break;
}
}
UpdateLastSeen(msg);
}
/// <summary>
/// Retrives value from other node
/// </summary>
/// <param name="node">Node to query</param>
/// <param name="valId">Value id</param>
/// <returns>Value if queried node has value, otherwise closest nodes to id</returns>
public NodeMessage FindValue(KadId id, KadId valId)
{
var bucket = BucketList.GetBucket(id);
return(FindValue(bucket.GetNode(id), valId));
}
/// <summary>
/// Store value in contact
/// </summary>
/// <param name="node">Contact node</param>
/// <param name="value">Value to store</param>
/// <returns>true, if node stored value</returns>
public bool StoreValue(KadId id, KadValue value)
{
var bucket = BucketList.GetBucket(id);
return(StoreValue(bucket.GetNode(id), value));
}
/// <summary>
/// Find contact's closest nodes to id
/// </summary>
/// <param name="node">Node to query</param>
/// <param name="id">Id to compare</param>
/// <returns>Closest nodes to id</returns>
public IEnumerable <KadContactNode> FindNode(KadId id, KadId idToFind)
{
var bucket = BucketList.GetBucket(id);
return(FindNode(bucket.GetNode(id), idToFind));
}
public KadIdToBaseComparator(KadId baseId)
{
_base = baseId;
}
