internal void StartConnecting()
        {
            if (_Disconnect.IsCancellationRequested)
            {
                return;
            }
            if (_ConnectedNodes.Count >= MaximumNodeConnection)
            {
                return;
            }
            if (_Connecting)
            {
                return;
            }
            Task.Factory.StartNew(() =>
            {
                if (Monitor.TryEnter(cs))
                {
                    _Connecting = true;
                    try
                    {
                        while (!_Disconnect.IsCancellationRequested && _ConnectedNodes.Count < MaximumNodeConnection)
                        {
                            Logs.NodeServer.LogInformation("Connected nodes {connectedNodeCount} / {maximumNodeCount} ", _ConnectedNodes.Count, MaximumNodeConnection);
                            var parameters = _ConnectionParameters.Clone();
                            parameters.TemplateBehaviors.Add(new NodesGroupBehavior(this));
                            parameters.ConnectCancellation = _Disconnect.Token;
                            var addrman = AddressManagerBehavior.GetAddrman(parameters);

                            if (addrman == null)
                            {
                                addrman = _DefaultAddressManager;
                                AddressManagerBehavior.SetAddrman(parameters, addrman);
                            }

                            Node node = null;
                            try
                            {
                                var groupSelector = CustomGroupSelector != null ? CustomGroupSelector :
                                                    AllowSameGroup ? WellKnownGroupSelectors.ByRandom : null;
                                node = Node.Connect(_Network, parameters, _ConnectedNodes.Select(n => n.RemoteSocketEndpoint as IPEndPoint).Where(e => e != null).ToArray(), groupSelector);
                                using (var timeout = CancellationTokenSource.CreateLinkedTokenSource(_Disconnect.Token))
                                {
                                    timeout.CancelAfter(5000);
                                    node.VersionHandshake(_Requirements, timeout.Token);
                                    Logs.NodeServer.LogInformation("Node successfully connected to and handshaked");
                                }
                            }
                            catch (OperationCanceledException ex)
                            {
                                if (_Disconnect.Token.IsCancellationRequested)
                                {
                                    break;
                                }
                                Logs.NodeServer.LogError(default, ex, "Timeout for picked node");
 public NodesGroup(
     Network network,
     NodeConnectionParameters connectionParameters = null,
     NodeRequirement requirements = null)
 {
     AllowSameGroup        = false;
     MaximumNodeConnection = 8;
     _Network              = network;
     cs                    = new object();
     _ConnectedNodes       = new NodesCollection();
     _ConnectionParameters = connectionParameters ?? new NodeConnectionParameters();
     _ConnectionParameters = _ConnectionParameters.Clone();
     _Requirements         = requirements ?? new NodeRequirement();
     _Disconnect           = new CancellationTokenSource();
 }
        internal void DiscoverPeers(Network network, NodeConnectionParameters parameters, int peerToFind)
        {
            Logs.NodeServer.LogTrace("Discovering nodes");

            int found = 0;

            {
                while (found < peerToFind)
                {
                    parameters.ConnectCancellation.ThrowIfCancellationRequested();

                    Logs.NodeServer.LogTrace("Remaining peer to get {remainingPeerCount}", (-found + peerToFind));

                    List <NetworkAddress> peers = new List <NetworkAddress>();
                    peers.AddRange(this.GetAddr());
                    if (peers.Count == 0)
                    {
                        PopulateTableWithDNSNodes(network, peers).GetAwaiter().GetResult();
                        PopulateTableWithHardNodes(network, peers);
                        peers = new List <NetworkAddress>(peers.OrderBy(a => RandomUtils.GetInt32()));
                        if (peers.Count == 0)
                        {
                            return;
                        }
                    }

                    CancellationTokenSource peerTableFull = new CancellationTokenSource();
                    CancellationToken       loopCancel    = CancellationTokenSource.CreateLinkedTokenSource(peerTableFull.Token, parameters.ConnectCancellation).Token;
                    try
                    {
                        Parallel.ForEach(peers, new ParallelOptions()
                        {
                            MaxDegreeOfParallelism = 5,
                            CancellationToken      = loopCancel,
                        }, p =>
                        {
                            using (CancellationTokenSource timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5)))
                                using (var cancelConnection = CancellationTokenSource.CreateLinkedTokenSource(timeout.Token, loopCancel))
                                {
                                    Node n = null;
                                    try
                                    {
                                        var param2 = parameters.Clone();
                                        param2.ConnectCancellation = cancelConnection.Token;
                                        var addrman = param2.TemplateBehaviors.Find <AddressManagerBehavior>();
                                        param2.TemplateBehaviors.Clear();
                                        param2.TemplateBehaviors.Add(addrman);
                                        n = Node.Connect(network, p.Endpoint, param2);
                                        n.VersionHandshake(cancelConnection.Token);
                                        n.MessageReceived += (s, a) =>
                                        {
                                            var addr = (a.Message.Payload as AddrPayload);
                                            if (addr != null)
                                            {
                                                Interlocked.Add(ref found, addr.Addresses.Length);
                                                if (found >= peerToFind)
                                                {
                                                    peerTableFull.Cancel();
                                                }
                                            }
                                        };
                                        n.SendMessageAsync(new GetAddrPayload());
                                        loopCancel.WaitHandle.WaitOne(2000);
                                    }
                                    catch
                                    {
                                    }
                                    finally
                                    {
                                        if (n != null)
                                        {
                                            n.DisconnectAsync();
                                        }
                                    }
                                }
                            if (found >= peerToFind)
                            {
                                peerTableFull.Cancel();
                            }
                            else
                            {
                                Logs.NodeServer.LogInformation("Need {neededPeerCount} more peers", (-found + peerToFind));
                            }
                        });
                    }
                    catch (OperationCanceledException)
                    {
                        if (parameters.ConnectCancellation.IsCancellationRequested)
                        {
                            throw;
                        }
                    }
                }
            }
        }