/// <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 <ContactNode> FindNode(ContactNode node, Id id)
{
Message.MnlMessage msg = new Message.MnlMessage.Builder()
.SetType(MessageType.Query)
.SetQueryType(QueryType.FindNode)
.SetOriginatorId(Id)
.Build();
msg.Payload.Add("target", id.Value);
Message.MnlMessage response = _server.SendMessageSync(node, msg, _validateMsgs, TimeoutInMSec).Response;
List <ContactNode> nodes = new List <ContactNode>();
if (response == null)
{
return(nodes);
}
UpdateLastSeen(node);
if (response.Payload.ContainsKey("nodes"))
{
byte[] nodeString = (byte[])response.Payload["nodes"];
int offset = 0;
while (offset < nodeString.Length)
{
nodes.Add(new ContactNode(nodeString, ref offset));
}
}
return(nodes);
}
public MnlMessage SendMessageSync(ContactNode toNode, Message.MnlMessage msg, bool validate, int timeout)
{
msg.TranId = GenerateTranId();
ManualResetEventSlim eventReset = new ManualResetEventSlim();
msg.AddCallback((m) => eventReset.Set());
ulong msgId = GetMessageId(toNode.EndPoint.Address, BitConverter.ToUInt16(Encoding.ASCII.GetBytes(msg.TranId), 0));
_messages.AddOrUpdate(msgId,
new PendingMnlMessage()
{
RecipientId = toNode.Id,
SentMessage = msg,
ValidateId = validate
}, (k, v) => v);
byte[] rawMsg = msg.ToBytes();
_udpClient.Send(rawMsg, rawMsg.Length, toNode.EndPoint);
if (eventReset.Wait(timeout))
{
PendingMnlMessage msgFromQueue;
if (_messages.TryRemove(msgId, out msgFromQueue))
{
return(msgFromQueue.SentMessage);
}
}
return(msg);
}
private void UpdateLastSeen(ContactNode node)
{
var bucket = BucketList.GetBucket(node.Id);
if (bucket.Contains(node.Id))
{
bucket.SeenNow(node);
}
}
/// <summary>
/// Pings other node
/// </summary>
/// <param name="node">Node to ping</param>
/// <returns></returns>
public MnlMessage Ping(ContactNode node)
{
Message.MnlMessage msg = new Message.MnlMessage.Builder()
.SetType(MessageType.Query)
.SetQueryType(QueryType.Ping)
.SetOriginatorId(Id)
.Build();
UpdateLastSeen(node);
return(_server.SendMessageSync(node, msg, _validateMsgs, TimeoutInMSec).Response);
}
/// <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 bool GetPeers(ContactNode node, Id infohash, out IEnumerable <ContactNode> nodes, out object token)
{
Message.MnlMessage msg = new Message.MnlMessage.Builder()
.SetType(MessageType.Query)
.SetQueryType(QueryType.GetPeers)
.SetOriginatorId(Id)
.SetInfohash(infohash)
.Build();
UpdateLastSeen(node);
Message.MnlMessage response = _server.SendMessageSync(node, msg, _validateMsgs, TimeoutInMSec).Response;
List <ContactNode> contacts = new List <ContactNode>();
nodes = contacts;
token = null;
if (response == null)
{
return(false);
}
if (response.Payload.ContainsKey("token"))
{
token = response.Payload["token"];
}
if (response.Payload.ContainsKey("values"))
{
List <object> valuesStrings = (List <object>)response.Payload["values"];
foreach (object peerInfo in valuesStrings)
{
contacts.Add(ContactNode.FromPeerInfo(peerInfo as byte[]));
}
return(true);
}
else if (response.Payload.ContainsKey("nodes"))
{
byte[] nodeString = (byte[])response.Payload["nodes"];
int offset = 0;
while (offset < nodeString.Length)
{
contacts.Add(new ContactNode(nodeString, ref offset));
}
return(false);
}
return(false);
}
public bool TryReplaceLeastSeenContactFromBucket(ContactNode newContact)
{
var bucket = Owner.BucketList.GetBucket(newContact.Id);
var leastSeen = bucket.GetLeastSeen();
Message.MnlMessage pongMsg = Owner.Ping(leastSeen);
if (pongMsg == null)
{
bucket.Replace(leastSeen.Id, newContact);
return(true);
}
return(false);
}
/// <summary>
/// Find contact's closest nodes to id
/// </summary>
/// <param name="node">Node to query</param>
/// <param name="id">Id to compare</param>
/// <returns></returns>
public MnlMessage AnnouncePeer(ContactNode node, Id infohash, int port, object token, int?impliedPort)
{
Message.MnlMessage msg = new Message.MnlMessage.Builder()
.SetType(MessageType.Query)
.SetQueryType(QueryType.AnnouncePeer)
.SetOriginatorId(Id)
.SetInfohash(infohash)
.Build();
msg.Payload.Add("port", port);
msg.Payload.Add("implied_port", impliedPort ?? 0);
msg.Payload.Add("token", token ?? new byte[0]);
UpdateLastSeen(node);
return(_server.SendMessageSync(node, msg, _validateMsgs, TimeoutInMSec).Response);
}
private void LookupNodes(Id nodeId, CancellationToken cancelToken)
{
SortedSet <Id> queriedNodes = new SortedSet <Id>(new Id.IdComparer());
List <Task> tasks = new List <Task>(MaxConcurrentThreads);
int triesCount = 0;
ContactNode closestContact = Owner.BucketList.GetClosestContactToId(nodeId);
if (closestContact == null)
{
return;
}
Id prevClosestId = closestContact.Id ^ nodeId;
while (queriedNodes.Count < 256)
{
var shortListSnapshot = Owner.BucketList.GetClosestNodes(nodeId, MaxConcurrentThreads).Where((n) => !queriedNodes.Contains(n.Id)).ToList();
foreach (var node in shortListSnapshot)
{
tasks.Add(Task.Run(() => {
IEnumerable <ContactNode> contacts = Owner.FindNode(node, nodeId);
foreach (var contact in contacts)
{
if (Owner.BucketList.Put(contact) == Buckets.BucketList.BucketPutResult.BucketIsFull)
{
TryReplaceLeastSeenContactFromBucket(contact);
}
}
Debug.WriteLine($"Added {contacts.Count()} contacts");
}));
queriedNodes.Add(node.Id);
if (tasks.Count >= MaxConcurrentThreads)
{
break;
}
Debug.WriteLine($"Queried nodes count - {queriedNodes.Count}");
}
try {
Task.WaitAll(tasks.ToArray(), cancelToken);
tasks.Clear();
} catch (OperationCanceledException) {
return;
}
ContactNode closestNode = Owner.BucketList.GetClosestContactToId(nodeId);
Id currentMin = closestNode.Id ^ nodeId;
if (currentMin >= prevClosestId)
{
if (triesCount < ReplicationCount)
{
triesCount++;
continue;
}
//Can't get any closer, stopping.
Debug.WriteLine($"Can't get any closer, breaking search");
break;
}
prevClosestId = currentMin;
}
}
/// <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 ProcessQuery(Message.MnlMessage msg, IPEndPoint origAddress)
{
switch (msg.QueryType)
{
case QueryType.Ping: {
_server.SendMessage(origAddress, PrepareResponse(msg));
break;
}
case QueryType.FindNode: {
Message.MnlMessage response = PrepareResponse(msg);
Id targetId = new Id((byte[])msg.Payload["target"]);
var closestNodes = BucketList.GetClosestNodes(targetId, NodesPerQuery);
response.Payload.Add("nodes", closestNodes.Select((n) => n.ToBytes()).ToList());
_server.SendMessage(origAddress, response);
break;
}
case QueryType.GetPeers: {
Message.MnlMessage response = PrepareResponse(msg);
Id targetId = new Id((byte[])msg.Payload["info_hash"]);
if (Storage.ContainsPeersFor(targetId))
{
response.Payload.Add("values", Storage.GetForinfoHash(targetId)
.Select((n) => n.ToBytes(true)).ToList());
response.Payload.Add("token", _tokenStorage.AcquireNewToken(origAddress.Address).AsBytes());
}
else
{
response.Payload.Add("nodes", BucketList.GetClosestNodes(targetId, NodesPerQuery)
.Select((n) => n.ToBytes()).ToList());
}
_server.SendMessage(origAddress, response);
break;
}
case QueryType.AnnouncePeer: {
Message.MnlMessage response = PrepareResponse(msg);
Token token = Token.FromBytes((byte[])msg.Payload["token"]);
if (_tokenStorage.Validate(origAddress.Address, token))
{
Id infoHash = new Id((byte[])msg.Payload["info_hash"]);
Id originatorId = new Id((byte[])msg.Payload["id"]);
Bucket originatorBucket = BucketList.GetBucket(originatorId);
ContactNode originatorNode = originatorBucket.GetNode(originatorId);
bool isImpliedPort = !msg.Payload.ContainsKey("port") || (int)msg.Payload["port"] > 0;
originatorNode.UtpPort = isImpliedPort ? originatorNode.EndPoint.Port : (int)msg.Payload["port"];
Storage.Put(originatorNode, infoHash);
_server.SendMessage(origAddress, response);
}
else
{
_server.SendBadToken(origAddress);
}
break;
}
}
Id msgOrigId = new Id((byte[])msg.Payload["id"]);
var bucket = BucketList.GetBucket(msgOrigId);
//UpdateLastSeen(bucket.GetNode(msgOrigId));
}