/// <summary>
        /// is used to expand neighborhood
        /// </summary>
        internal async Task RegisterAsync(uint minimalDistanceToNeighbor, ushort busySectorIds, byte numberOfHopsRemaining, byte numberOfRandomHopsRemaining, double[] directionVectorNullable, bool allowConnectionsToRequesterRegistrationId)
        {
            _engine.WriteToLog_reg_requesterSide_detail($">> ConnectionToNeighbor.RegisterAsync(minimalDistanceToNeighbor={minimalDistanceToNeighbor}", null, null);
            _localDrpPeer.CurrentRegistrationOperationsCount++;

            try
            {
                var        newConnectionToNeighbor = new ConnectionToNeighbor(_engine, _localDrpPeer, ConnectedDrpPeerInitiatedBy.localPeer, null);
                PongPacket pong;
                //  PendingLowLevelUdpRequest pendingPingRequest;
                var req = new RegisterRequestPacket
                {
                    RequesterRegistrationId   = _localDrpPeer.Configuration.LocalPeerRegistrationId,
                    ReqTimestamp64            = _engine.Timestamp64,
                    MinimalDistanceToNeighbor = minimalDistanceToNeighbor,
                    RequesterNatBehaviour     = _engine.LocalNatBehaviour,
                    AllowConnectionsToRequesterRegistrationId = allowConnectionsToRequesterRegistrationId,
                    RequesterNeighborsBusySectorIds           = busySectorIds,
                    NumberOfHopsRemaining       = numberOfHopsRemaining,
                    NumberOfRandomHopsRemaining = numberOfRandomHopsRemaining,
                    RequesterEcdhePublicKey     = new EcdhPublicKey(newConnectionToNeighbor.LocalEcdhe25519PublicKey),
                    ReqP2pSeq16 = GetNewRequestP2pSeq16_P2P(),
                    EpEndpoint  = this.RemoteEndpoint,
                    DirectionVectorNullableD = directionVectorNullable
                };
                var logger = new Logger(Engine, LocalDrpPeer, req, DrpPeerEngine.VisionChannelModuleName_reg_requesterSide);
                try
                {
                    _engine.RecentUniquePublicEcdhKeys.AssertIsUnique(req.RequesterEcdhePublicKey.Ecdh25519PublicKey, $"req.RequesterEcdhePublicKey {req}");

                    req.RequesterSignature = RegistrationSignature.Sign(_engine.CryptoLibrary,
                                                                        w => req.GetSharedSignedFields(w, false),
                                                                        _localDrpPeer.Configuration.LocalPeerRegistrationPrivateKey
                                                                        );

                    var reqToAck1Stopwatch = Stopwatch.StartNew();

                    #region wait for ACK1, respond with NPACK
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sending {req}, waiting for NPACK. ReqP2pSeq16={req.ReqP2pSeq16}");
                    }

                    var sentRequest = new SentRequest(Engine, logger, this.RemoteEndpoint, this, req.Encode_OptionallySignNeighborHMAC(this),
                                                      req.ReqP2pSeq16, RegisterAck1Packet.GetScanner(logger, req, this));
                    var ack1UdpData = await sentRequest.SendRequestAsync("reg req ack1 42084");

                    var ack1 = RegisterAck1Packet.DecodeAndOptionallyVerify(logger, ack1UdpData, req, newConnectionToNeighbor);
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"verified ACK1, sending NPACK to ACK1");
                    }

                    _engine.SendNeighborPeerAckResponseToRegisterAck1(ack1, this);
                    #endregion

                    if (newConnectionToNeighbor.IsDisposed)
                    {
                        logger.WriteToLog_needsAttention($"connection {newConnectionToNeighbor} is disposed during reg. request 5345322345");
                        return;
                    }
                    if (IsDisposed)
                    {
                        logger.WriteToLog_needsAttention($"connection {this} is disposed during reg. request 5345322345");
                        return;
                    }
                    _engine.RecentUniquePublicEcdhKeys.AssertIsUnique(ack1.ResponderEcdhePublicKey.Ecdh25519PublicKey, $"ack1.ResponderEcdhePublicKey from {newConnectionToNeighbor}");

                    newConnectionToNeighbor.LocalEndpoint        = this.LocalEndpoint;
                    newConnectionToNeighbor.RemoteRegistrationId = ack1.ResponderRegistrationId;
                    reqToAck1Stopwatch.Stop();
                    var reqToAck1TimeMs = reqToAck1Stopwatch.Elapsed.TotalMilliseconds;
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"measured REQ-ACK1 RTT = {(int)reqToAck1TimeMs}ms");
                    }

                    #region send ACK2, encode local IP
                    var ack2 = new RegisterAck2Packet
                    {
                        ReqTimestamp64          = req.ReqTimestamp64,
                        RequesterRegistrationId = _localDrpPeer.Configuration.LocalPeerRegistrationId,
                        ReqP2pSeq16             = GetNewRequestP2pSeq16_P2P(),
                    };
                    ack2.ToRequesterTxParametersEncrypted = newConnectionToNeighbor.Encrypt_ack2_ToRequesterTxParametersEncrypted_AtRequester(logger, req, ack1, ack2);
                    newConnectionToNeighbor.InitializeP2pStream(req, ack1, ack2);
                    ack2.RequesterSignature = RegistrationSignature.Sign(_engine.CryptoLibrary, w =>
                    {
                        req.GetSharedSignedFields(w, true);
                        ack1.GetSharedSignedFields(w, true, true);
                        ack2.GetSharedSignedFields(w, false, true);
                    },
                                                                         _localDrpPeer.Configuration.LocalPeerRegistrationPrivateKey
                                                                         );

                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sending ACK2 (in response to ACK1), waiting for NPACK");
                    }
                    await _engine.OptionallySendUdpRequestAsync_Retransmit_WaitForNeighborPeerAck("ack2 1235739", ack2.Encode_OptionallySignNeighborHMAC(this), this.RemoteEndpoint, ack2.ReqP2pSeq16);

                    #endregion

                    var neighborWaitTimeMs = reqToAck1TimeMs * 0.5 - 100; if (neighborWaitTimeMs < 0)
                    {
                        neighborWaitTimeMs = 0;
                    }
                    if (neighborWaitTimeMs > 20)
                    {
                        await _engine.EngineThreadQueue.WaitAsync(TimeSpan.FromMilliseconds(neighborWaitTimeMs), "neighborWaitTimeMs45236"); // wait until the ACK2 reaches neighbor N via peers
                    }


                    if (newConnectionToNeighbor.IsDisposed)
                    {
                        logger.WriteToLog_needsAttention($"connection {newConnectionToNeighbor} is disposed during reg. request 234574568");
                        return;
                    }
                    if (IsDisposed)
                    {
                        logger.WriteToLog_needsAttention($"connection {this} is disposed during reg. request 234574568");
                        return;
                    }

                    _localDrpPeer.AddToConnectedNeighbors(newConnectionToNeighbor, req);

                    #region send ping request directly to neighbor N, retransmit
                    var pingRequest = newConnectionToNeighbor.CreatePing(true, false, _localDrpPeer.ConnectedNeighborsBusySectorIds, _localDrpPeer.AnotherNeighborToSameSectorExists(newConnectionToNeighbor));
                    newConnectionToNeighbor.InitialPendingPingRequest = new PendingLowLevelUdpRequest("pendingPingRequest 12247", newConnectionToNeighbor.RemoteEndpoint,
                                                                                                      PongPacket.GetScanner(newConnectionToNeighbor.LocalNeighborToken32, pingRequest.PingRequestId32),
                                                                                                      _engine.DateTimeNowUtc,
                                                                                                      _engine.Configuration.InitialPingRequests_ExpirationTimeoutS,
                                                                                                      pingRequest.Encode(),
                                                                                                      _engine.Configuration.InitialPingRequests_InitialRetransmissionTimeoutS,
                                                                                                      _engine.Configuration.InitialPingRequests_RetransmissionTimeoutIncrement
                                                                                                      );

                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sending PING, waiting for PONG");
                    }
                    var pongPacketData = await _engine.SendUdpRequestAsync_Retransmit(newConnectionToNeighbor.InitialPendingPingRequest);

                    if (pongPacketData == null)
                    {
                        throw new DrpTimeoutException($"reg. requester initial PING to {newConnectionToNeighbor} (timeout={_engine.Configuration.InitialPingRequests_ExpirationTimeoutS}s)");
                    }
                    if (newConnectionToNeighbor.IsDisposed)
                    {
                        logger.WriteToLog_needsAttention($"connection {newConnectionToNeighbor} is disposed during reg. request 548798");
                        return;
                    }
                    if (IsDisposed)
                    {
                        logger.WriteToLog_needsAttention($"connection {this} is disposed during reg. request 548798");
                        return;
                    }

                    pong = PongPacket.DecodeAndVerify(_engine.CryptoLibrary,
                                                      pongPacketData, pingRequest, newConnectionToNeighbor,
                                                      true);
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"verified PONG");
                    }
                    newConnectionToNeighbor.OnReceivedVerifiedPong(pong, newConnectionToNeighbor.InitialPendingPingRequest.ResponseReceivedAtUtc.Value,
                                                                   newConnectionToNeighbor.InitialPendingPingRequest.ResponseReceivedAtUtc.Value - newConnectionToNeighbor.InitialPendingPingRequest.InitialTxTimeUTC.Value);
                    #endregion
                }
                catch
                {
                    // todo update QoS
                    newConnectionToNeighbor.Dispose(); // remove from token32 table
                    throw;
                }

                #region send registration confirmation packet to X->N
                try
                {
                    if (newConnectionToNeighbor.IsDisposed)
                    {
                        logger.WriteToLog_needsAttention($"connection {newConnectionToNeighbor} is disposed during reg. request 541687987");
                        return;
                    }
                    if (IsDisposed)
                    {
                        logger.WriteToLog_needsAttention($"connection {this} is disposed during reg. request 541687987");
                        return;
                    }
                    var cfm = new RegisterConfirmationPacket
                    {
                        ReqTimestamp64          = req.ReqTimestamp64,
                        RequesterRegistrationId = _localDrpPeer.Configuration.LocalPeerRegistrationId,
                        ResponderRegistrationConfirmationSignature = pong.ResponderRegistrationConfirmationSignature,
                        ReqP2pSeq16 = GetNewRequestP2pSeq16_P2P()
                    };
                    cfm.RequesterRegistrationConfirmationSignature = RegistrationSignature.Sign(_engine.CryptoLibrary,
                                                                                                w => newConnectionToNeighbor.GetRequesterRegistrationConfirmationSignatureFields(w, cfm.ResponderRegistrationConfirmationSignature),
                                                                                                _localDrpPeer.Configuration.LocalPeerRegistrationPrivateKey);
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sending CFM, waiting for NPACK");
                    }
                    await _engine.OptionallySendUdpRequestAsync_Retransmit_WaitForNeighborPeerAck("cfm 14478", cfm.Encode_OptionallySignNeighborHMAC(this), this.RemoteEndpoint, cfm.ReqP2pSeq16);

                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"received NPACK to CFM");
                    }
                }
                catch (DrpTimeoutException exc)
                {  // we ingnore exceptions here, just wite warning to log.  the connection is alive already, as direct ping channel to neighbor is set up
                    logger.WriteToLog_needsAttention($"... registration confirmation request failed: {exc}");
                }
                catch (Exception exc)
                {  // we ingnore exceptions here, just wite warning to log.  the connection is alive already, as direct ping channel to neighbor is set up
                    logger.WriteToLog_mediumPain($"... registration confirmation request failed: {exc}");
                }
                #endregion

                return;// newConnectionToNeighbor;
            }
            finally
            {
                _localDrpPeer.CurrentRegistrationOperationsCount--;
            }
        }
Beispiel #2
0
        /// <returns>null if registration failed with timeout or some error code</returns>
        public async Task <ConnectionToNeighbor> RegisterAsync(LocalDrpPeer localDrpPeer, IPEndPoint epEndpoint, uint minimalDistanceToNeighbor,
                                                               byte numberofHops, double[] directionVectorNullable, bool allowConnectionsToRequesterRegistrationId) // engine thread
        {
            var regSW = Stopwatch.StartNew();

            WriteToLog_reg_requesterSide_higherLevelDetail($"connecting via EntryPeer {epEndpoint}", null, null);
            localDrpPeer.CurrentRegistrationOperationsCount++;
            try
            {
                #region PoW1
                RegisterPow1ResponsePacket pow1ResponsePacket = null;
                if (!Configuration.SandboxModeOnly_DisablePoW)
                {
                    WriteToLog_reg_requesterSide_detail($"generating PoW1 request", null, null);
                    var pow1SW = Stopwatch.StartNew();

                    await PowThreadQueue.EnqueueAsync("pow1 6318");

                    WriteToLog_reg_requesterSide_detail($"generating PoW1 request @pow thread", null, null);
                    var registerPow1RequestPacket = GenerateRegisterPow1RequestPacket(localDrpPeer.PublicIpApiProviderResponse.GetAddressBytes(), Timestamp32S);
                    await EngineThreadQueue.EnqueueAsync("pow1 234709");

                    WriteToLog_reg_requesterSide_detail($"generated PoW1 request @engine thread", null, null);

                    // send register pow1 request
                    if (pow1SW.Elapsed.TotalMilliseconds > 3000)
                    {
                        WriteToLog_reg_requesterSide_lightPain($"PoW1 took {(int)pow1SW.Elapsed.TotalMilliseconds}ms", null, null);
                    }
                    WriteToLog_reg_requesterSide_detail($"PoW1 took {(int)pow1SW.Elapsed.TotalMilliseconds}ms. sending PoW1 request", null, null);
                    var rpPow1ResponsePacketData = await SendUdpRequestAsync_Retransmit(
                        new PendingLowLevelUdpRequest("rpPow1 469", epEndpoint,
                                                      RegisterPow1ResponsePacket.GetScanner(registerPow1RequestPacket.Pow1RequestId),
                                                      DateTimeNowUtc,
                                                      Configuration.UdpLowLevelRequests_ExpirationTimeoutS,
                                                      registerPow1RequestPacket.Encode(),
                                                      Configuration.UdpLowLevelRequests_InitialRetransmissionTimeoutS,
                                                      Configuration.UdpLowLevelRequests_RetransmissionTimeoutIncrement
                                                      ));

                    //  wait for response, retransmit
                    if (rpPow1ResponsePacketData == null)
                    {
                        throw new DrpTimeoutException($"pow1 request to EP '{epEndpoint}' (timeout={Configuration.UdpLowLevelRequests_ExpirationTimeoutS}s)");
                    }
                    ;
                    pow1ResponsePacket = new RegisterPow1ResponsePacket(rpPow1ResponsePacketData);
                    WriteToLog_reg_requesterSide_detail($"got PoW1 response with status={pow1ResponsePacket.StatusCode}", null, null);
                    if (pow1ResponsePacket.StatusCode != RegisterPow1ResponseStatusCode.succeeded_Pow2Challenge)
                    {
                        throw new Pow1RejectedException(pow1ResponsePacket.StatusCode);
                    }
                }
                #endregion

                var newConnectionToNeighbor = new ConnectionToNeighbor(this, localDrpPeer, ConnectedDrpPeerInitiatedBy.localPeer, null);

                PongPacket pong;
                var        req = new RegisterRequestPacket
                {
                    RequesterRegistrationId   = localDrpPeer.Configuration.LocalPeerRegistrationId,
                    ReqTimestamp64            = Timestamp64,
                    MinimalDistanceToNeighbor = minimalDistanceToNeighbor,
                    RequesterNatBehaviour     = LocalNatBehaviour,
                    AllowConnectionsToRequesterRegistrationId = allowConnectionsToRequesterRegistrationId,
                    NumberOfHopsRemaining   = numberofHops,
                    RequesterEcdhePublicKey = new EcdhPublicKey(newConnectionToNeighbor.LocalEcdhe25519PublicKey),
                    ReqP2pSeq16             = GetNewNpaSeq16_AtoEP(),
                    EpEndpoint = epEndpoint,
                    DirectionVectorNullableD = directionVectorNullable
                };
                var logger = new Logger(this, localDrpPeer, req, VisionChannelModuleName_reg_requesterSide);
                try
                {
                    #region register REQ  PoW2
                    RecentUniquePublicEcdhKeys.AssertIsUnique(req.RequesterEcdhePublicKey.Ecdh25519PublicKey, $"req.RequesterEcdhePublicKey {req}"); // this is used in non-standard way when routing registration requests to same (local) reg. ID,  too

                    var pow2SW = Stopwatch.StartNew();
                    if (!Configuration.SandboxModeOnly_DisablePoW)
                    {
                        await PowThreadQueue.EnqueueAsync("pow2 23465");

                        if (logger.WriteToLog_detail_enabled)
                        {
                            logger.WriteToLog_detail($"calculating PoW2 @pow thread");
                        }
                        GenerateRegisterReqPow2(req, pow1ResponsePacket.ProofOfWork2Request);
                        await EngineThreadQueue.EnqueueAsync("pow2 2496");

                        if (logger.WriteToLog_detail_enabled)
                        {
                            logger.WriteToLog_detail($"calculated PoW2 @engine thread");
                        }
                    }
                    else
                    {
                        req.ProofOfWork2 = new byte[64];
                    }
                    pow2SW.Stop();
                    if (pow2SW.Elapsed.TotalMilliseconds > 3000)
                    {
                        logger.WriteToLog_lightPain($"PoW2 took {(int)pow2SW.Elapsed.TotalMilliseconds}ms");
                    }

                    req.RequesterSignature = RegistrationSignature.Sign(_cryptoLibrary,
                                                                        w => req.GetSharedSignedFields(w, false),
                                                                        localDrpPeer.Configuration.LocalPeerRegistrationPrivateKey
                                                                        );
                    var reqToAck1Stopwatch = Stopwatch.StartNew();

                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"PoW2 took {(int)pow2SW.Elapsed.TotalMilliseconds}ms. sending REQ, waiting for NPACK. ReqP2pSeq16={req.ReqP2pSeq16}");
                    }
                    #endregion

                    //  var reqSW = Stopwatch.StartNew();
                    #region wait for ACK1
                    var sentRequest = new SentRequest(this, logger, epEndpoint, null, req.Encode_OptionallySignNeighborHMAC(null), req.ReqP2pSeq16, RegisterAck1Packet.GetScanner(logger, req));
                    var ack1UdpData = await sentRequest.SendRequestAsync("reg req ack1 367097");

                    var ack1 = RegisterAck1Packet.DecodeAndOptionallyVerify(logger, ack1UdpData, req, newConnectionToNeighbor);
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"verified ACK1. RequesterEndpoint={ack1.RequesterEndpoint}");
                    }
                    #endregion



                    // check if it matches to previously known local public IP
                    if (ack1.RequesterEndpoint.Address.Equals(localDrpPeer.PublicIpApiProviderResponse) == false)
                    {
                        // MITM attack / EP sent local (requester) endpoint IP some bad IP address
                        throw new PossibleAttackException();
                    }
                    RecentUniquePublicEcdhKeys.AssertIsUnique(ack1.ResponderEcdhePublicKey.Ecdh25519PublicKey, $"ack1.ResponderEcdhePublicKey from {epEndpoint}");

                    newConnectionToNeighbor.LocalEndpoint        = ack1.RequesterEndpoint;
                    newConnectionToNeighbor.RemoteRegistrationId = ack1.ResponderRegistrationId;
                    reqToAck1Stopwatch.Stop();
                    var reqToAck1TimeMs = reqToAck1Stopwatch.Elapsed.TotalMilliseconds;
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"measured  REQ-ACK1_RTT={(int)reqToAck1TimeMs}ms");
                    }

                    #region send ACK2, encode local IP
                    var ack2 = new RegisterAck2Packet
                    {
                        ReqTimestamp64          = req.ReqTimestamp64,
                        RequesterRegistrationId = localDrpPeer.Configuration.LocalPeerRegistrationId,
                        ReqP2pSeq16             = GetNewNpaSeq16_AtoEP()
                    };
                    ack2.ToRequesterTxParametersEncrypted = newConnectionToNeighbor.Encrypt_ack2_ToRequesterTxParametersEncrypted_AtRequester(logger, req, ack1, ack2);
                    newConnectionToNeighbor.InitializeP2pStream(req, ack1, ack2);
                    ack2.RequesterSignature = RegistrationSignature.Sign(_cryptoLibrary, w =>
                    {
                        req.GetSharedSignedFields(w, true);
                        ack1.GetSharedSignedFields(w, true, true);
                        ack2.GetSharedSignedFields(w, false, true);
                    },
                                                                         localDrpPeer.Configuration.LocalPeerRegistrationPrivateKey
                                                                         );

                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sending ACK2 (in response to ACK1), waiting for NPACK");
                    }
                    RespondToRequestAndRetransmissions(ack1UdpData, ack2.Encode_OptionallySignNeighborHMAC(null), epEndpoint);
                    await OptionallySendUdpRequestAsync_Retransmit_WaitForNeighborPeerAck("ack2 46873", null, epEndpoint, ack2.ReqP2pSeq16);

                    #endregion

                    var neighborWaitTimeMs = reqToAck1TimeMs * 0.5 - 250; if (neighborWaitTimeMs < 0)
                    {
                        neighborWaitTimeMs = 0;
                    }
                    if (neighborWaitTimeMs > 20)
                    {
                        if (logger.WriteToLog_detail_enabled)
                        {
                            logger.WriteToLog_detail($"awaiting {(int)neighborWaitTimeMs}ms before PING...");
                        }
                        await EngineThreadQueue.WaitAsync(TimeSpan.FromMilliseconds(neighborWaitTimeMs), "before PING 34589"); // wait until the ACK2 reaches neighbor N via peers

                        if (logger.WriteToLog_detail_enabled)
                        {
                            logger.WriteToLog_detail($"... awaiting is complete");
                        }
                    }

                    localDrpPeer.AddToConnectedNeighbors(newConnectionToNeighbor, req);

                    #region send ping request directly to neighbor N, retransmit
                    var pingRequest = newConnectionToNeighbor.CreatePing(true, false, localDrpPeer.ConnectedNeighborsBusySectorIds, localDrpPeer.AnotherNeighborToSameSectorExists(newConnectionToNeighbor));
                    newConnectionToNeighbor.InitialPendingPingRequest = new PendingLowLevelUdpRequest("pingRequest 3850", newConnectionToNeighbor.RemoteEndpoint,
                                                                                                      PongPacket.GetScanner(newConnectionToNeighbor.LocalNeighborToken32, pingRequest.PingRequestId32),
                                                                                                      DateTimeNowUtc,
                                                                                                      Configuration.InitialPingRequests_ExpirationTimeoutS,
                                                                                                      pingRequest.Encode(),
                                                                                                      Configuration.InitialPingRequests_InitialRetransmissionTimeoutS,
                                                                                                      Configuration.InitialPingRequests_RetransmissionTimeoutIncrement
                                                                                                      );

                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sending PING neighborToken32={pingRequest.NeighborToken32}, waiting for PONG");
                    }
                    var pongPacketData = await SendUdpRequestAsync_Retransmit(newConnectionToNeighbor.InitialPendingPingRequest);

                    if (pongPacketData == null)
                    {
                        throw new DrpTimeoutException($"initial reg. requester PING to {newConnectionToNeighbor} (timeout={Configuration.InitialPingRequests_ExpirationTimeoutS}s)");
                    }
                    if (newConnectionToNeighbor.IsDisposed)
                    {
                        throw new ObjectDisposedException($"initial reg. requester PING to {newConnectionToNeighbor} (special case: connection is disposed)", (Exception)null);                                     // ping timeout already destroyed the connection, so PONG response here is too late
                    }
                    pong = PongPacket.DecodeAndVerify(_cryptoLibrary,
                                                      pongPacketData, pingRequest, newConnectionToNeighbor,
                                                      true);
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"verified PONG");
                    }
                    newConnectionToNeighbor.OnReceivedVerifiedPong(pong, newConnectionToNeighbor.InitialPendingPingRequest.ResponseReceivedAtUtc.Value,
                                                                   newConnectionToNeighbor.InitialPendingPingRequest.ResponseReceivedAtUtc.Value - newConnectionToNeighbor.InitialPendingPingRequest.InitialTxTimeUTC.Value);
                    #endregion
                }
                catch
                {
                    // todo update QoS
                    newConnectionToNeighbor.Dispose(); // remove from token32 table
                    throw;
                }

                #region send registration confirmation packet to EP->X->N
                try
                {
                    var cfm = new RegisterConfirmationPacket
                    {
                        ReqTimestamp64          = req.ReqTimestamp64,
                        RequesterRegistrationId = localDrpPeer.Configuration.LocalPeerRegistrationId,
                        ResponderRegistrationConfirmationSignature = pong.ResponderRegistrationConfirmationSignature,
                        ReqP2pSeq16 = GetNewNpaSeq16_AtoEP()
                    };
                    cfm.RequesterRegistrationConfirmationSignature = RegistrationSignature.Sign(_cryptoLibrary,
                                                                                                w => newConnectionToNeighbor.GetRequesterRegistrationConfirmationSignatureFields(w, cfm.ResponderRegistrationConfirmationSignature),
                                                                                                localDrpPeer.Configuration.LocalPeerRegistrationPrivateKey);
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sending CFM, waiting for NPACK");
                    }
                    await OptionallySendUdpRequestAsync_Retransmit_WaitForNeighborPeerAck("cfm 32107", cfm.Encode_OptionallySignNeighborHMAC(null), epEndpoint, cfm.ReqP2pSeq16);

                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"received NPACK to CFM");
                    }
                }
                catch (DrpTimeoutException exc)
                {  // we ingnore exceptions here, just wite warning to log.  the connection is alive already, as direct ping channel to neighbor is set up
                    logger.WriteToLog_needsAttention($"... registration confirmation request failed: {exc}");
                }
                catch (Exception exc)
                {  // we ingnore exceptions here, just wite warning to log.  the connection is alive already, as direct ping channel to neighbor is set up
                    logger.WriteToLog_mediumPain($"... registration confirmation request failed: {exc}");
                }
                #endregion

                regSW.Stop();
                if (regSW.Elapsed.TotalMilliseconds > 5000)
                {
                    logger.WriteToLog_lightPain($"registration is completed in {(int)regSW.Elapsed.TotalMilliseconds}ms");
                }
                else
                {
                    logger.WriteToLog_higherLevelDetail($"registration is completed in {(int)regSW.Elapsed.TotalMilliseconds}ms");
                };

                return(newConnectionToNeighbor);
            }
            finally
            {
                localDrpPeer.CurrentRegistrationOperationsCount--;
            }
        }