public static void GetRequesterRegistrationConfirmationSignatureFields(BinaryWriter writer, RegistrationSignature responderRegistrationConfirmationSignature,
RegisterRequestPacket req, RegisterAck1Packet ack1, RegisterAck2Packet ack2)
{
responderRegistrationConfirmationSignature.Encode(writer);
req.GetSharedSignedFields(writer, true);
ack1.GetSharedSignedFields(writer, true, true);
ack2.GetSharedSignedFields(writer, true, true);
writer.Write(RequesterRegistrationConfirmationSignature_MagicNumber);
}
void AssertMatchToSyn(RegisterRequestPacket remoteRegisterReq)
{
if (!this.RequesterRegistrationId.Equals(remoteRegisterReq.RequesterRegistrationId))
{
throw new UnmatchedFieldsException();
}
if (this.ReqTimestamp64 != remoteRegisterReq.ReqTimestamp64)
{
throw new UnmatchedFieldsException();
}
}
void AssertMatchToRegisterReq(RegisterRequestPacket req)
{
if (req.RequesterRegistrationId.Equals(this.RequesterRegistrationId) == false)
{
throw new UnmatchedFieldsException();
}
if (req.ReqTimestamp64 != this.ReqTimestamp64)
{
throw new UnmatchedFieldsException();
}
}
/// <summary>
/// creates a scanner that finds ACK1 that matches to REQ
/// </summary>
/// <param name="connectionToNeighborNullable">
/// peer that responds to REQ with ACK1
/// if not null - the scanner will verify ACK1.NeighborHMAC
/// </param>
public static LowLevelUdpResponseScanner GetScanner(Logger logger, RegisterRequestPacket req, ConnectionToNeighbor connectionToNeighborNullable = null)
{
BinaryProcedures.CreateBinaryWriter(out var ms, out var w);
w.Write((byte)PacketTypes.RegisterAck1);
w.Write((byte)0);
if (connectionToNeighborNullable != null)
{
connectionToNeighborNullable.LocalNeighborToken32.Encode(w);
}
req.RequesterRegistrationId.Encode(w);
w.Write(req.ReqTimestamp64);
var r = new LowLevelUdpResponseScanner
{
ResponseFirstBytes = ms.ToArray(),
IgnoredByteAtOffset1 = 1 // ignore flags
};
if (connectionToNeighborNullable != null)
{
r.OptionalFilter = (responseData) =>
{
if (connectionToNeighborNullable.IsDisposed)
{
logger.WriteToLog_needsAttention("ignoring ACK1: connection is disposed");
return(false);
}
var ack1 = DecodeAndOptionallyVerify(logger, responseData, null, null);
if (ack1.NeighborHMAC.Equals(connectionToNeighborNullable.GetNeighborHMAC(ack1.GetSignedFieldsForNeighborHMAC)) == false)
{
logger.WriteToLog_attacks("ignoring ACK1: received NeighborHMAC is invalid");
return(false);
}
return(true);
};
}
return(r);
}
/// <param name="newConnectionAtResponderToRequesterNullable">
/// direct P2P stream from N to A
/// if newConnectionAtResponderToRequesterNullable is specified, the procedure
/// verifies RequesterHMAC, decrypts endpoint of A (ToRequesterTxParametersEncrypted), initializes P2P stream
/// </param>
public static RegisterAck2Packet Decode_OptionallyVerify_InitializeP2pStreamAtResponder(Logger logger, byte[] registerAckPacketData,
RegisterRequestPacket reqNullable,
RegisterAck1Packet ack1Nullable,
ConnectionToNeighbor newConnectionAtResponderToRequesterNullable
)
{
var reader = BinaryProcedures.CreateBinaryReader(registerAckPacketData, 1);
var ack = new RegisterAck2Packet();
ack.DecodedUdpPayloadData = registerAckPacketData;
ack.Flags = reader.ReadByte();
if ((ack.Flags & FlagsMask_MustBeZero) != 0)
{
throw new NotImplementedException();
}
if ((ack.Flags & Flag_AtoEP) == 0)
{
ack.NeighborToken32 = NeighborToken32.Decode(reader);
}
ack.ReqTimestamp64 = reader.ReadInt64();
ack.RequesterRegistrationId = RegistrationId.Decode(reader);
if (reqNullable != null)
{
ack.AssertMatchToSyn(reqNullable);
}
ack.ToRequesterTxParametersEncrypted = reader.ReadBytes(ToRequesterTxParametersEncryptedLength);
if (newConnectionAtResponderToRequesterNullable != null)
{
newConnectionAtResponderToRequesterNullable.Decrypt_ack2_ToRequesterTxParametersEncrypted_AtResponder_InitializeP2pStream(logger, reqNullable, ack1Nullable, ack);
}
ack.RequesterSignature = RegistrationSignature.Decode(reader);
if (newConnectionAtResponderToRequesterNullable != null)
{
if (reqNullable == null)
{
throw new ArgumentException();
}
if (ack1Nullable == null)
{
throw new ArgumentException();
}
if (!ack.RequesterSignature.Verify(newConnectionAtResponderToRequesterNullable.Engine.CryptoLibrary,
w =>
{
reqNullable.GetSharedSignedFields(w, true);
ack1Nullable.GetSharedSignedFields(w, true, true);
ack.GetSharedSignedFields(w, false, true);
},
reqNullable.RequesterRegistrationId))
{
throw new BadSignatureException("invalid REGISTER ACK2 RequesterSignature 6106");
}
}
ack.ReqP2pSeq16 = RequestP2pSequenceNumber16.Decode(reader);
if ((ack.Flags & Flag_AtoEP) == 0)
{
ack.NeighborHMAC = HMAC.Decode(reader); // is verified by Filter
}
return(ack);
}
/// <summary>
/// when REQ is received from neighbor, verifies senderHMAC and NeighborToken32
/// </summary>
/// <param name="receivedFromNeighborNullable">is NULL when decoding REQ from A at EP</param>
public static RegisterRequestPacket Decode_OptionallyVerifyNeighborHMAC(byte[] udpData, ConnectionToNeighbor receivedFromNeighborNullable, int numberOfDimensions)
{
var r = new RegisterRequestPacket();
r.DecodedUdpPayloadData = udpData;
var reader = PacketProcedures.CreateBinaryReader(udpData, 1);
var flags = reader.ReadByte();
if ((flags & FlagsMask_MustBeZero) != 0)
{
throw new NotImplementedException();
}
if ((flags & Flag_AtoEP) == 0)
{
if (receivedFromNeighborNullable == null)
{
throw new UnmatchedFieldsException();
}
r.NeighborToken32 = NeighborToken32.Decode(reader);
if (receivedFromNeighborNullable.LocalNeighborToken32.Equals(r.NeighborToken32) == false)
{
throw new UnmatchedFieldsException();
}
}
else
{
if (receivedFromNeighborNullable != null)
{
throw new UnmatchedFieldsException();
}
}
r.RequesterRegistrationId = RegistrationId.Decode(reader);
r.RequesterNeighborsBusySectorIds = reader.ReadUInt16();
r.RequesterEcdhePublicKey = EcdhPublicKey.Decode(reader);
r.ReqTimestamp64 = reader.ReadInt64();
r.MinimalDistanceToNeighbor = reader.ReadUInt32();
if ((flags & Flag_DirectionVectorExists) != 0)
{
r.DirectionVectorNullable = new sbyte[numberOfDimensions];
for (int i = 0; i < numberOfDimensions; i++)
{
r.DirectionVectorNullable[i] = reader.ReadSByte();
}
}
r.EpEndpoint = PacketProcedures.DecodeIPEndPoint(reader);
r.RequesterSignature = RegistrationSignature.Decode(reader);
if ((flags & Flag_AtoEP) != 0)
{
r.ProofOfWork2 = reader.ReadBytes(64);
}
r.NumberOfHopsRemaining = reader.ReadByte();
r.NumberOfRandomHopsRemaining = reader.ReadByte();
r.ReqP2pSeq16 = RequestP2pSequenceNumber16.Decode(reader);
if ((flags & Flag_AtoEP) == 0)
{
r.NeighborHMAC = HMAC.Decode(reader);
if (r.NeighborHMAC.Equals(receivedFromNeighborNullable.GetNeighborHMAC(r.GetSignedFieldsForNeighborHMAC)) == false)
{
throw new BadSignatureException("invalid REGISTER REQ NeighborHMAC 1573");
}
}
return(r);
}
/// <summary>
/// decodes the packet, decrypts ToNeighborTxParametersEncrypted, verifies NeighborSignature, verifies match to register REQ
/// </summary>
/// <param name="newConnectionToNeighborAtRequesterNullable">if not null (at requester) - this procedure verifies ResponderSignature</param>
/// <param name="reader">is positioned after first byte = packet type</param>
public static RegisterAck1Packet DecodeAndOptionallyVerify(Logger logger, byte[] ack1UdpData, RegisterRequestPacket reqNullable,
ConnectionToNeighbor newConnectionToNeighborAtRequesterNullable)
{
var reader = BinaryProcedures.CreateBinaryReader(ack1UdpData, 1);
var ack1 = new RegisterAck1Packet();
ack1.DecodedUdpPayloadData = ack1UdpData;
ack1.Flags = reader.ReadByte();
if ((ack1.Flags & Flag_EPtoA) == 0)
{
ack1.NeighborToken32 = NeighborToken32.Decode(reader);
}
if ((ack1.Flags & FlagsMask_MustBeZero) != 0)
{
throw new NotImplementedException();
}
ack1.RequesterRegistrationId = RegistrationId.Decode(reader);
ack1.ReqTimestamp64 = reader.ReadInt64();
ack1.ResponderEcdhePublicKey = EcdhPublicKey.Decode(reader);
ack1.ToResponderTxParametersEncrypted = reader.ReadBytes(ToResponderTxParametersEncryptedLength);
ack1.ResponderRegistrationId = RegistrationId.Decode(reader);
if (newConnectionToNeighborAtRequesterNullable != null)
{
if (reqNullable == null)
{
throw new ArgumentException();
}
ack1.ResponderSignature = RegistrationSignature.DecodeAndVerify(
reader, newConnectionToNeighborAtRequesterNullable.Engine.CryptoLibrary,
w =>
{
reqNullable.GetSharedSignedFields(w, true);
ack1.GetSharedSignedFields(w, false, true);
},
ack1.ResponderRegistrationId);
}
else
{ // at proxy we don't verify responder's signature, to avoid high spending of resources
ack1.ResponderSignature = RegistrationSignature.Decode(reader);
}
if (reqNullable != null)
{
ack1.AssertMatchToRegisterReq(reqNullable);
if (newConnectionToNeighborAtRequesterNullable != null)
{
newConnectionToNeighborAtRequesterNullable.Decrypt_ack1_ToResponderTxParametersEncrypted_AtRequester_DeriveSharedDhSecret(logger, reqNullable, ack1);
}
}
if ((ack1.Flags & Flag_EPtoA) != 0)
{
ack1.RequesterEndpoint = BinaryProcedures.DecodeIPEndPoint(reader);
}
else
{
ack1.ReqP2pSeq16 = RequestP2pSequenceNumber16.Decode(reader);
ack1.NeighborHMAC = HMAC.Decode(reader);
}
return(ack1);
}
public static RegisterConfirmationPacket DecodeAndOptionallyVerify(byte[] regCfmUdpPayload, RegisterRequestPacket reqNullable, ConnectionToNeighbor newConnectionToRequesterAtResponderNullable)
{
var reader = BinaryProcedures.CreateBinaryReader(regCfmUdpPayload, 1);
var cfm = new RegisterConfirmationPacket();
cfm.DecodedUdpPayloadData = regCfmUdpPayload;
cfm.Flags = reader.ReadByte();
if ((cfm.Flags & FlagsMask_MustBeZero) != 0)
{
throw new NotImplementedException();
}
if ((cfm.Flags & Flag_AtoEP) == 0)
{
cfm.NeighborToken32 = NeighborToken32.Decode(reader);
}
cfm.ReqTimestamp64 = reader.ReadInt64();
cfm.RequesterRegistrationId = RegistrationId.Decode(reader);
if (reqNullable != null)
{
cfm.AssertMatchToRegisterReq(reqNullable);
}
if (newConnectionToRequesterAtResponderNullable != null)
{
cfm.ResponderRegistrationConfirmationSignature = RegistrationSignature.DecodeAndVerify(reader, newConnectionToRequesterAtResponderNullable.Engine.CryptoLibrary,
w => newConnectionToRequesterAtResponderNullable.GetResponderRegistrationConfirmationSignatureFields(w),
newConnectionToRequesterAtResponderNullable.LocalDrpPeer.Configuration.LocalPeerRegistrationId
);
cfm.RequesterRegistrationConfirmationSignature = RegistrationSignature.DecodeAndVerify(reader, newConnectionToRequesterAtResponderNullable.Engine.CryptoLibrary,
w => newConnectionToRequesterAtResponderNullable.GetRequesterRegistrationConfirmationSignatureFields(w, cfm.ResponderRegistrationConfirmationSignature),
newConnectionToRequesterAtResponderNullable.RemoteRegistrationId
);
}
else
{
cfm.ResponderRegistrationConfirmationSignature = RegistrationSignature.Decode(reader);
cfm.RequesterRegistrationConfirmationSignature = RegistrationSignature.Decode(reader);
}
cfm.ReqP2pSeq16 = RequestP2pSequenceNumber16.Decode(reader);
if ((cfm.Flags & Flag_AtoEP) == 0)
{
cfm.NeighborHMAC = HMAC.Decode(reader);
}
return(cfm);
}