Ejemplo n.º 1
0
        /// <summary>
        /// main register responder proc for both A-EP and P2P modes
        /// in P2P mode Timestamp32S, NeighborToken32 and NeighborHMAC are verified at this time
        /// </summary>
        /// <param name="receivedFromInP2pMode">
        /// is null in A-EP mode
        /// </param>
        internal async Task AcceptRegisterRequestAsync(LocalDrpPeer acceptAt, RoutedRequest routedRequest) // engine thread
        {
            var logger = routedRequest.Logger;

            logger.ModuleName = VisionChannelModuleName_reg_responderSide;
            var req = routedRequest.RegisterReq;

            if (req.RequesterRegistrationId.Equals(acceptAt.Configuration.LocalPeerRegistrationId))
            {
                throw new InvalidOperationException();
            }

            // check  signature of requester (A)
            if (!req.RequesterSignature.Verify(_cryptoLibrary,
                                               w => req.GetSharedSignedFields(w, false),
                                               req.RequesterRegistrationId
                                               )
                )
            {
                throw new BadSignatureException("invalid REGISTER REQ RequesterSignature 2396");
            }

            if (routedRequest.ReceivedFromNeighborNullable == null)
            { // A-EP mode
                if (req.EpEndpoint.Address.Equals(acceptAt.PublicIpApiProviderResponse) == false)
                {
                    throw new PossibleAttackException();
                }
            }

            if (PendingRegisterRequestExists(req.RequesterRegistrationId))
            {
                // received duplicate REGISTER REQ packet
                logger.WriteToLog_needsAttention($"ignoring duplicate registration request {req.RequesterRegistrationId} from {routedRequest.ReceivedFromEndpoint}");
                return;
            }

            if (!RecentUniqueAcceptedRegistrationRequests.Filter(req.GetUniqueRequestIdFields))
            {
                logger.WriteToLog_needsAttention($"ignoring registration request {req.RequesterRegistrationId} ts={req.ReqTimestamp64} from {routedRequest.ReceivedFromEndpoint} with non-unique request ID fields");
                return;
            }

            logger.WriteToLog_higherLevelDetail($"accepting registration from {routedRequest.ReceivedFromEndpoint}: ReqP2pSeq16={req.ReqP2pSeq16}, NumberOfHopsRemaining={req.NumberOfHopsRemaining}, epEndpoint={req.EpEndpoint}, sourcePeer={routedRequest.ReceivedFromNeighborNullable}, ts={req.ReqTimestamp64}");

            if (!RecentUniquePublicEcdhKeys.Filter(req.RequesterEcdhePublicKey.Ecdh25519PublicKey))
            {
                logger.WriteToLog_needsAttention($"ignoring registration request {req.RequesterRegistrationId} from {routedRequest.ReceivedFromEndpoint} with non-unique RequesterEcdhePublicKey");
                return;
            }

            _pendingRegisterRequests.Add(req.RequesterRegistrationId);
            try
            {
                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"sending NPACK to REQ to {routedRequest.ReceivedFromEndpoint} (delay={routedRequest.ReqReceivedSw_ms}ms)");
                }
                routedRequest.SendNeighborPeerAck_accepted_IfNotAlreadyReplied();

                var newConnectionToNeighbor = new ConnectionToNeighbor(this, acceptAt, ConnectedDrpPeerInitiatedBy.remotePeer, req.RequesterRegistrationId)
                {
                    LocalEndpoint = routedRequest.ReceivedFromNeighborNullable?.LocalEndpoint ?? req.EpEndpoint,
                };
                byte[] ack1UdpData;
                try
                {
                    var ack1 = new RegisterAck1Packet
                    {
                        RequesterRegistrationId = req.RequesterRegistrationId,
                        ReqTimestamp64          = req.ReqTimestamp64,
                        ResponderEcdhePublicKey = new EcdhPublicKey(newConnectionToNeighbor.LocalEcdhe25519PublicKey),
                        ResponderRegistrationId = acceptAt.Configuration.LocalPeerRegistrationId,
                        ReqP2pSeq16             = GetNewNpaSeq16_AtoEP(),
                    };
                    RecentUniquePublicEcdhKeys.AssertIsUnique(ack1.ResponderEcdhePublicKey.Ecdh25519PublicKey, $"ack1.ResponderEcdhePublicKey");
                    ack1.ToResponderTxParametersEncrypted = newConnectionToNeighbor.Encrypt_ack1_ToResponderTxParametersEncrypted_AtResponder_DeriveSharedDhSecret(logger, req, ack1, routedRequest.ReceivedFromNeighborNullable);
                    ack1.ResponderSignature = RegistrationSignature.Sign(_cryptoLibrary,
                                                                         (w2) =>
                    {
                        req.GetSharedSignedFields(w2, true);
                        ack1.GetSharedSignedFields(w2, false, true);
                    },
                                                                         acceptAt.Configuration.LocalPeerRegistrationPrivateKey);
                    if (routedRequest.ReceivedFromNeighborNullable == null)
                    {
                        ack1.RequesterEndpoint = routedRequest.ReceivedFromEndpoint;
                    }
                    ack1UdpData = ack1.Encode_OpionallySignNeighborHMAC(routedRequest.ReceivedFromNeighborNullable);

                    var    ack2Scanner = RegisterAck2Packet.GetScanner(logger, routedRequest.ReceivedFromNeighborNullable, req);
                    var    requesterVisibleDescription = routedRequest.ReceivedFromNeighborNullable?.ToString() ?? routedRequest.ReceivedFromEndpoint.ToString();
                    byte[] ack2UdpData;
                    if (routedRequest.ReceivedFromNeighborNullable == null)
                    {   // wait for ACK2, retransmitting ACK1
                        if (logger.WriteToLog_detail_enabled)
                        {
                            logger.WriteToLog_detail($"sending ACK1, waiting for ACK2");
                        }
                        ack2UdpData = await OptionallySendUdpRequestAsync_Retransmit_WaitForResponse("ack2 33469", requesterVisibleDescription, ack1UdpData, routedRequest.ReceivedFromEndpoint, ack2Scanner);
                    }
                    else
                    {   // retransmit ACK1 until NPACK (via P2P); at same time wait for ACK
                        if (logger.WriteToLog_detail_enabled)
                        {
                            logger.WriteToLog_detail($"sending ACK1, awaiting for NPACK");
                        }
                        _ = OptionallySendUdpRequestAsync_Retransmit_WaitForNeighborPeerAck("ack1 423087", ack1UdpData, routedRequest.ReceivedFromEndpoint,
                                                                                            ack1.ReqP2pSeq16, routedRequest.ReceivedFromNeighborNullable, ack1.GetSignedFieldsForNeighborHMAC);
                        // not waiting for NPACK, wait for ACK
                        if (logger.WriteToLog_detail_enabled)
                        {
                            logger.WriteToLog_detail($"waiting for ACK2");
                        }
                        ack2UdpData = await OptionallySendUdpRequestAsync_Retransmit_WaitForResponse("ack2 46051", requesterVisibleDescription, null, routedRequest.ReceivedFromEndpoint, ack2Scanner);
                    }

                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"received ACK2");
                    }
                    var ack2 = RegisterAck2Packet.Decode_OptionallyVerify_InitializeP2pStreamAtResponder(logger, ack2UdpData, req, ack1, newConnectionToNeighbor);
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"verified ACK2");
                    }

                    acceptAt.AddToConnectedNeighbors(newConnectionToNeighbor, req);                                                                  // added to list here in order to respond to ping requests from A

                    SendNeighborPeerAckResponseToRegisterAck2(ack2, routedRequest.ReceivedFromEndpoint, routedRequest.ReceivedFromNeighborNullable); // send NPACK to ACK

                    _ = WaitForRegistrationConfirmationRequestAsync(requesterVisibleDescription, logger, routedRequest.ReceivedFromEndpoint, req, newConnectionToNeighbor, routedRequest.ReceivedFromNeighborNullable);

                    #region send ping, verify pong
                    var ping = newConnectionToNeighbor.CreatePing(true, false, acceptAt.ConnectedNeighborsBusySectorIds, acceptAt.AnotherNeighborToSameSectorExists(newConnectionToNeighbor));

                    var pendingPingRequest = new PendingLowLevelUdpRequest("pendingPingRequest 693", newConnectionToNeighbor.RemoteEndpoint,
                                                                           PongPacket.GetScanner(newConnectionToNeighbor.LocalNeighborToken32, ping.PingRequestId32), DateTimeNowUtc,
                                                                           Configuration.InitialPingRequests_ExpirationTimeoutS,
                                                                           ping.Encode(),
                                                                           Configuration.InitialPingRequests_InitialRetransmissionTimeoutS,
                                                                           Configuration.InitialPingRequests_RetransmissionTimeoutIncrement
                                                                           );

                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sent PING");
                    }
                    var pongPacketData = await SendUdpRequestAsync_Retransmit(pendingPingRequest); // wait for pong from A

                    if (pongPacketData == null)
                    {
                        throw new DrpTimeoutException($"reg. responder initial PING request to {newConnectionToNeighbor} (timeout={Configuration.InitialPingRequests_ExpirationTimeoutS}s)");
                    }
                    var pong = PongPacket.DecodeAndVerify(_cryptoLibrary,
                                                          pongPacketData, ping, newConnectionToNeighbor,
                                                          true);
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"verified PONG");
                    }
                    newConnectionToNeighbor.OnReceivedVerifiedPong(pong, pendingPingRequest.ResponseReceivedAtUtc.Value,
                                                                   pendingPingRequest.ResponseReceivedAtUtc.Value - pendingPingRequest.InitialTxTimeUTC.Value);
                    #endregion
                }
                catch (Exception exc)
                {
                    newConnectionToNeighbor.Dispose();
                    throw exc;
                }
            }
            catch (DrpTimeoutException exc)
            {
                logger.WriteToLog_needsAttention($"could not accept REGISTER request: {exc}");
            }
            catch (Exception exc)
            {
                logger.WriteToLog_mediumPain($"could not accept REGISTER request: {exc}");
            }
            finally
            {
                _pendingRegisterRequests.Remove(req.RequesterRegistrationId);
            }
        }
Ejemplo n.º 2
0
        /// <summary>
        /// main register responder proc for both A-EP and P2P modes
        /// in P2P mode NeighborToken32 and NeighborHMAC are verified at this time
        /// </summary>
        /// <param name="receivedFromInP2pMode">
        /// is null in A-EP mode
        /// </param>
        /// <returns>
        /// true to retry the request with another neighbor (if the request needs to be "rerouted")
        /// </returns>
        internal async Task <bool> ProxyRegisterRequestAsync(RoutedRequest routedRequest, ConnectionToNeighbor destinationPeer) // engine thread
        {
            routedRequest.ReceivedFromNeighborNullable?.AssertIsNotDisposed();
            var req    = routedRequest.RegisterReq;
            var logger = routedRequest.Logger;

            logger.ModuleName = VisionChannelModuleName_reg_proxySide;

            if (!ValidateReceivedReqTimestamp64(req.ReqTimestamp64))
            {
                logger.WriteToLog_needsAttention($"rejecting REGISTER request {req.RequesterRegistrationId}: invalid REGISTER REQ 457 ReqTimestamp64={MiscProcedures.Int64ticksToDateTime(req.ReqTimestamp64)}");
                //   await routedRequest.SendErrorResponse(ResponseOrFailureCode.failure_numberOfHopsRemainingReachedZero);
                return(false);
            }

            if (PendingRegisterRequestExists(req.RequesterRegistrationId))
            {
                logger.WriteToLog_higherLevelDetail($"rejecting duplicate request {req}: requesterEndpoint={routedRequest.ReceivedFromEndpoint}");
                await routedRequest.SendErrorResponse(ResponseOrFailureCode.failure_routeIsUnavailable);

                return(false);
            }

            if (req.NumberOfHopsRemaining > RegisterRequestPacket.MaxNumberOfHopsRemaining || req.NumberOfRandomHopsRemaining > RegisterRequestPacket.MaxNumberOfHopsRemaining)
            {
                logger.WriteToLog_needsAttention($"rejecting {req}: invalid number of hops remaining");
                await routedRequest.SendErrorResponse(ResponseOrFailureCode.failure_routeIsUnavailable);

                return(false);
            }

            if (!routedRequest.CheckedRecentUniqueProxiedRequests)
            {
                var recentUniqueProxiedRegistrationRequests = req.RandomModeAtThisHop ? RecentUniqueProxiedRegistrationRequests_RandomHop : RecentUniqueProxiedRegistrationRequests_NonRandomHop;
                if (!recentUniqueProxiedRegistrationRequests.Filter(req.GetUniqueRequestIdFields))
                {
                    logger.WriteToLog_higherLevelDetail($"rejecting non-unique request {req}: requesterEndpoint={routedRequest.ReceivedFromEndpoint}");
                    await routedRequest.SendErrorResponse(ResponseOrFailureCode.failure_routeIsUnavailable);

                    return(false);
                }
                routedRequest.CheckedRecentUniqueProxiedRequests = true;
            }

            logger.WriteToLog_higherLevelDetail($"proxying {req}: requesterEndpoint={routedRequest.ReceivedFromEndpoint}, NumberOfHopsRemaining={req.NumberOfHopsRemaining}, ReqP2pSeq16={req.ReqP2pSeq16}, destinationPeer={destinationPeer}, sourcePeer={routedRequest.ReceivedFromNeighborNullable}");

            if (!ValidateReceivedReqTimestamp64(req.ReqTimestamp64))
            {
                throw new BadSignatureException($"invalid REGISTER REQ ReqTimestamp64={MiscProcedures.Int64ticksToDateTime(req.ReqTimestamp64)} 3507");
            }

            req.NumberOfHopsRemaining--;
            if (req.NumberOfHopsRemaining == 0)
            {
                logger.WriteToLog_needsAttention($"rejecting REGISTER request {req.RequesterRegistrationId}: max hops reached");
                await routedRequest.SendErrorResponse(ResponseOrFailureCode.failure_numberOfHopsRemainingReachedZero);

                return(false);
            }

            _pendingRegisterRequests.Add(req.RequesterRegistrationId);
            try
            {
                // send NPACK to source peer
                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"sending NPACK to REQ source peer (delay={routedRequest.ReqReceivedSw_ms}ms)");
                }
                routedRequest.SendNeighborPeerAck_accepted_IfNotAlreadyReplied();

                if (req.NumberOfRandomHopsRemaining >= 1)
                {
                    req.NumberOfRandomHopsRemaining--;
                }
                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"decremented number of hops in {req}: NumberOfHopsRemaining={req.NumberOfHopsRemaining}, NumberOfRandomHopsRemaining={req.NumberOfRandomHopsRemaining}");
                }

                req.ReqP2pSeq16 = destinationPeer.GetNewRequestP2pSeq16_P2P();
                byte[] ack1UdpData;
                try
                {
                    var sentRequest = new SentRequest(this, logger, destinationPeer.RemoteEndpoint, destinationPeer, req.Encode_OptionallySignNeighborHMAC(destinationPeer),
                                                      req.ReqP2pSeq16, RegisterAck1Packet.GetScanner(logger, req, destinationPeer));

                    // send (proxy) REQ to responder. wait for NPACK, verify NPACK.senderHMAC, retransmit REQ
                    // wait for ACK1 from destination peer
                    // verify NeighborHMAC
                    // var ack1R = await sentRequest.SendRequestAsync_NoExc("ack1 34601"); ////////////////////////////////// new method
                    ack1UdpData = await sentRequest.SendRequestAsync("ack1 34601");

                    //  if (logger.WriteToLog_detail2_enabled) logger.WriteToLog_detail("got ACK1 result");

                    if (routedRequest.ReceivedFromNeighborNullable?.IsDisposed == true)
                    {
                        logger.WriteToLog_needsAttention($"sourcePeer={routedRequest.ReceivedFromNeighborNullable} is disposed during proxying 52460");
                        return(false);
                    }
                    if (destinationPeer?.IsDisposed == true)
                    {
                        logger.WriteToLog_needsAttention($"destinationPeer={destinationPeer} is disposed during proxying 52460");
                        return(false);
                    }

                    //if (ack1R.ResponseCode != ResponseOrFailureCode.accepted)
                    //{
                    //    logger.WriteToLog_higherLevelDetail($"got response={ack1R.ResponseCode} from destination {destinationPeer}");
                    //    if (ack1R.ResponseCode == ResponseOrFailureCode.failure_routeIsUnavailable)
                    //        req.NumberOfHopsRemaining++; // roll back previous decrement for a new trial
                    //    return true; // will retry
                    //}
                    //ack1UdpData = ack1R.UdpData;
                }
                catch (RequestRejectedException reqExc)
                {
                    logger.WriteToLog_higherLevelDetail($"got exception: response={reqExc.ResponseCode} from destination {destinationPeer}");
                    if (reqExc.ResponseCode == ResponseOrFailureCode.failure_numberOfHopsRemainingReachedZero)
                    {
                        await routedRequest.SendErrorResponse(ResponseOrFailureCode.failure_numberOfHopsRemainingReachedZero);

                        return(false);
                    }

                    if (routedRequest.ReceivedFromNeighborNullable?.IsDisposed == true)
                    {
                        logger.WriteToLog_needsAttention($"sourcePeer={routedRequest.ReceivedFromNeighborNullable} is disposed during proxying 35346232");
                        return(false);
                    }
                    if (reqExc.ResponseCode == ResponseOrFailureCode.failure_routeIsUnavailable)
                    {
                        req.NumberOfHopsRemaining++; // roll back previous decrement for a new trial
                    }

                    return(true); // will retry
                }
                catch (DrpTimeoutException exc)
                {
                    logger.WriteToLog_higherLevelDetail($"got timeout error when requesting {destinationPeer}: {exc.Message}");
                    req.NumberOfHopsRemaining++; // roll back previous decrement for a new trial
                    return(true);                // will retry
                }
                catch (Exception reqExc)
                {
                    logger.WriteToLog_mediumPain($"could not proxy REGISTER request: {reqExc}");
                    if (routedRequest.ReceivedFromNeighborNullable?.IsDisposed == true)
                    {
                        logger.WriteToLog_needsAttention($"sourcePeer={routedRequest.ReceivedFromNeighborNullable} is disposed during proxying 76897805");
                        return(false);
                    }
                    return(true); // will retry
                }

                var tr1  = CreateTracker("ack1 34601 2");
                var ack1 = RegisterAck1Packet.DecodeAndOptionallyVerify(logger, ack1UdpData, req, null);
                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"verified ACK1 from destination");
                }

                // respond with NPACK
                SendNeighborPeerAckResponseToRegisterAck1(ack1, destinationPeer);

                // send ACK1 to source peer
                // wait for ACK / NPACK
                if (routedRequest.ReceivedFromNeighborNullable != null)
                {   // P2P mode
                    routedRequest.ReceivedFromNeighborNullable.AssertIsNotDisposed();
                    ack1.ReqP2pSeq16 = routedRequest.ReceivedFromNeighborNullable.GetNewRequestP2pSeq16_P2P();
                }
                else
                {   // A-EP mode
                    ack1.RequesterEndpoint = routedRequest.ReceivedFromEndpoint;
                }
                var ack1UdpDataTx = ack1.Encode_OpionallySignNeighborHMAC(routedRequest.ReceivedFromNeighborNullable);

                var sourcePeerVisibleDescription = routedRequest.ReceivedFromNeighborNullable?.ToString() ?? routedRequest.ReceivedFromEndpoint.ToString();
                var ack2Scanner = RegisterAck2Packet.GetScanner(logger, routedRequest.ReceivedFromNeighborNullable, req);
                tr1.Dispose();
                byte[] ack2UdpData;
                if (routedRequest.ReceivedFromNeighborNullable == null)
                {   // A-EP mode: wait for ACK2, retransmitting ACK1
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sending ACK1, waiting for ACK2");
                    }
                    ack2UdpData = await OptionallySendUdpRequestAsync_Retransmit_WaitForResponse("ack2 12368", sourcePeerVisibleDescription,
                                                                                                 ack1UdpDataTx, routedRequest.ReceivedFromEndpoint, ack2Scanner);
                }
                else
                {   // P2P mode: retransmit ACK1 until NPACK (via P2P); at same time wait for ACK2
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sending ACK1, awaiting for NPACK");
                    }
                    _ = OptionallySendUdpRequestAsync_Retransmit_WaitForNeighborPeerAck("ack1 3686", ack1UdpDataTx, routedRequest.ReceivedFromEndpoint,
                                                                                        ack1.ReqP2pSeq16, routedRequest.ReceivedFromNeighborNullable, ack1.GetSignedFieldsForNeighborHMAC);
                    // not waiting for NPACK, wait for ACK2
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"waiting for ACK2");
                    }
                    ack2UdpData = await OptionallySendUdpRequestAsync_Retransmit_WaitForResponse("ack2 345209", sourcePeerVisibleDescription,
                                                                                                 null, routedRequest.ReceivedFromEndpoint, ack2Scanner);
                }

                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"received ACK2");
                }
                if (routedRequest.ReceivedFromNeighborNullable?.IsDisposed == true)
                {
                    logger.WriteToLog_needsAttention($"sourcePeer={routedRequest.ReceivedFromNeighborNullable} is disposed during proxying 2345135");
                    return(false);
                }
                if (destinationPeer?.IsDisposed == true)
                {
                    logger.WriteToLog_needsAttention($"destinationPeer={destinationPeer} is disposed during proxying 2345135");
                    return(false);
                }
                var ack2 = RegisterAck2Packet.Decode_OptionallyVerify_InitializeP2pStreamAtResponder(logger, ack2UdpData, null, null, null);

                // send NPACK to source peer
                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"sending NPACK to ACK2 to source peer");
                }
                SendNeighborPeerAckResponseToRegisterAck2(ack2, routedRequest.ReceivedFromEndpoint, routedRequest.ReceivedFromNeighborNullable);

                // send ACK2 to destination peer
                // put ACK2.ReqP2pSeq16, sendertoken32, senderHMAC
                // wait for NPACK
                if (destinationPeer.IsDisposed == true)
                {
                    logger.WriteToLog_needsAttention($"destinationPeer={destinationPeer} is disposed during proxying 345784567");
                    return(false);
                }
                if (routedRequest.ReceivedFromNeighborNullable?.IsDisposed == true)
                {
                    logger.WriteToLog_needsAttention($"sourcePeer={routedRequest.ReceivedFromNeighborNullable} is disposed during proxying 345784567");
                    return(false);
                }
                ack2.ReqP2pSeq16 = destinationPeer.GetNewRequestP2pSeq16_P2P();
                await destinationPeer.SendUdpRequestAsync_Retransmit_WaitForNPACK("ack2 41937", ack2.Encode_OptionallySignNeighborHMAC(destinationPeer),
                                                                                  ack2.ReqP2pSeq16, ack2.GetSignedFieldsForNeighborHMAC);

                if (routedRequest.ReceivedFromNeighborNullable?.IsDisposed == true)
                {
                    logger.WriteToLog_needsAttention($"sourcePeer={routedRequest.ReceivedFromNeighborNullable} is disposed during proxying 234646");
                    return(false);
                }
                if (destinationPeer?.IsDisposed == true)
                {
                    logger.WriteToLog_needsAttention($"destinationPeer={destinationPeer} is disposed during proxying 234646");
                    return(false);
                }

                // wait for CFM from source peer
                var cfmUdpData = await OptionallySendUdpRequestAsync_Retransmit_WaitForResponse("cfm 234789", sourcePeerVisibleDescription, null,
                                                                                                routedRequest.ReceivedFromEndpoint,
                                                                                                RegisterConfirmationPacket.GetScanner(logger, routedRequest.ReceivedFromNeighborNullable, req)
                                                                                                );

                var cfm = RegisterConfirmationPacket.DecodeAndOptionallyVerify(cfmUdpData, null, null);
                if (routedRequest.ReceivedFromNeighborNullable?.IsDisposed == true)
                {
                    logger.WriteToLog_needsAttention($"sourcePeer={routedRequest.ReceivedFromNeighborNullable} is disposed during proxying 3452326");
                    return(false);
                }
                if (destinationPeer?.IsDisposed == true)
                {
                    logger.WriteToLog_needsAttention($"destinationPeer={destinationPeer} is disposed during proxying 3452326");
                    return(false);
                }

                // TODO verify signatures and update QoS

                // send NPACK to source peer
                SendNeighborPeerAckResponseToRegisterCfm(cfm, routedRequest.ReceivedFromEndpoint, routedRequest.ReceivedFromNeighborNullable);

                // send CFM to responder
                // wait for NPACK from destination peer, retransmit
                if (destinationPeer.IsDisposed == true)
                {
                    logger.WriteToLog_needsAttention($"destinationPeer={destinationPeer} is disposed during proxying 123678");
                    return(false);
                }
                if (routedRequest.ReceivedFromNeighborNullable?.IsDisposed == true)
                {
                    logger.WriteToLog_needsAttention($"sourcePeer={routedRequest.ReceivedFromNeighborNullable} is disposed during proxying 123678");
                    return(false);
                }
                cfm.ReqP2pSeq16 = destinationPeer.GetNewRequestP2pSeq16_P2P();
                await destinationPeer.SendUdpRequestAsync_Retransmit_WaitForNPACK("cfm 1357", cfm.Encode_OptionallySignNeighborHMAC(destinationPeer),
                                                                                  cfm.ReqP2pSeq16, cfm.GetSignedFieldsForNeighborHMAC);


                logger.WriteToLog_higherLevelDetail($"proxying {req} is successfully complete");
            }
            catch (DrpTimeoutException exc)
            {
                logger.WriteToLog_lightPain($"could not proxy REGISTER: request timeout: {exc.Message}");
            }
            catch (Exception exc)
            {
                logger.WriteToLog_mediumPain($"could not proxy REGISTER request: {exc}");
            }
            finally
            {
                _pendingRegisterRequests.Remove(req.RequesterRegistrationId);
            }

            return(false);
        }