/// <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);
}
public Builder(byte[] msg)
{
Bencoder bencoder = new Bencoder();
var decodedMsg = bencoder.DecodeElement(msg);
Dictionary <string, object> msgFields = (Dictionary <string, object>)decodedMsg;
_msg = new MnlMessage();
try {
_msg.TranId = Bencoder.DefEncoding.GetString((byte[])msgFields["t"]);
} catch (KeyNotFoundException) {
throw new MalformedPacketException("t");
}
try {
_msg.Type = (MessageType)(Bencoder.DefEncoding.GetString((byte[])msgFields["y"])[0]);
} catch (KeyNotFoundException) {
throw new MalformedPacketException("y");
}
if (msgFields.ContainsKey("q"))
{
_msg.QueryType = Bencoder.DefEncoding.GetString((byte[])msgFields["q"]);
}
switch (_msg.Type)
{
case MessageType.Query:
try {
_msg.Payload = (Dictionary <string, object>)msgFields["a"];
} catch (KeyNotFoundException) {
throw new MalformedPacketException("a");
}
break;
case MessageType.Response:
try {
_msg.Payload = (Dictionary <string, object>)msgFields["r"];
} catch (KeyNotFoundException) {
throw new MalformedPacketException("r");
}
break;
case MessageType.Error:
try {
List <object> errList = (List <object>)msgFields["e"];
int codeIdx = errList[0] is int? 0 : 1;
_msg.ErrorCode = (ErrorType)errList[codeIdx];
if (errList.Count > 1)
{
_msg.ErrorMessage = Bencoder.DefEncoding.GetString((byte[])errList[codeIdx == 0 ? 1 : 0]); //TODO: ???
}
} catch (KeyNotFoundException) {
throw new MalformedPacketException("e");
}
return;
}
_msg.OriginatorId = new Id((byte[])_msg.Payload["id"]);
}
private MnlMessage PrepareResponse(Message.MnlMessage toMsg)
{
return(new Message.MnlMessage.Builder()
.SetTranId(toMsg.TranId)
.SetType(MessageType.Response)
.SetOriginatorId(Id)
.Build());
}
/// <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);
}
public void SetResponse(MnlMessage response)
{
Response = response;
OnResponse?.Invoke(response);
}
public Builder()
{
_msg = new MnlMessage();
}
private void ListenIncoming(Node ownerNode)
{
while (!_stopped)
{
try {
IPEndPoint incomingIpEndPoint = new IPEndPoint(IPAddress.Any, EndPoint.Port);
byte[] rawMsg = _udpClient.Receive(ref incomingIpEndPoint);
if (!IsLegitMnlDhtMessage(rawMsg))
{
continue;
}
Message.MnlMessage incomingMsg = null;
try {
incomingMsg = new Message.MnlMessage.Builder(rawMsg).Build();
} catch (Bittorrent.InvalidFieldException ife) {
MnlMessage errMessage = new MnlMessage.Builder()
.SetTranId(GenerateTranId())
.SetType(MessageType.Error)
.SetErrorCode(ErrorType.ProtocolError)
.SetErrorMessage(ife.Message)
.Build();
Debug.WriteLine($"Sending incorrect field message {ife.Message}");
SendMessage(incomingIpEndPoint, errMessage);
continue;
} catch (MalformedPacketException mpe) {
MnlMessage errMessage = new MnlMessage.Builder()
.SetTranId(GenerateTranId())
.SetType(MessageType.Error)
.SetErrorCode(ErrorType.ProtocolError)
.SetErrorMessage(mpe.Message)
.Build();
Debug.WriteLine($"Sending malformed packet message {mpe.Message}");
SendMessage(incomingIpEndPoint, errMessage);
continue;
}
ulong msgIdx = GetMessageId(incomingIpEndPoint.Address, BitConverter.ToUInt16(Encoding.ASCII.GetBytes(incomingMsg.TranId.PadLeft(2, '\0')), 0));
if (_messages.ContainsKey(msgIdx))
{
PendingMnlMessage rqMsg;
if (_messages.TryRemove(msgIdx, out rqMsg))
{
if (incomingMsg.Type == MessageType.Error)
{
Debug.WriteLine($"Recieved error {incomingMsg.ErrorMessage}");
switch (incomingMsg.ErrorCode)
{
case ErrorType.ProtocolError:
case ErrorType.MethodUnknown:
Debug.WriteLine($"!!!Error {incomingMsg.ErrorMessage}");
break;
default:
continue;
}
}
if (rqMsg.ValidateId)
{
if (rqMsg.RecipientId != incomingMsg.OriginatorId)
{
Debug.WriteLine($"Node {incomingIpEndPoint} id mismatch!");
OnMaliciousMessage?.Invoke(incomingIpEndPoint, rqMsg.RecipientId, rqMsg.SentMessage);
continue;
}
}
rqMsg.SentMessage.SetResponse(incomingMsg);
}
}
else
{
if (incomingMsg.Type == MessageType.Query)
{
ownerNode.ProcessQuery(incomingMsg, incomingIpEndPoint);
}
}
} catch (SocketException se) {
if (se.SocketErrorCode != SocketError.Interrupted)
{
throw;
}
}
}
}
public void SendMessage(IPEndPoint toEndPoint, Message.MnlMessage msg)
{
byte[] rawMsg = msg.ToBytes();
_udpClient.Send(rawMsg, rawMsg.Length, toEndPoint);
}
/// <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));
}
