private void NetworkLoop()
{
while (!Cancellator.IsCancellationRequested)
{
try
{
if (!Socket.Poll(100000, SelectMode.SelectRead))
{
continue;
}
}
catch (SocketException) { break; }
byte[] Data;
try
{
byte[] Buffer = new byte[8];
Stream.Read(Buffer, 0, 8);
int PacketLength = ToInt32(Buffer, 0);
if (ToUInt32(Buffer, 4) != 0x31305456U)
{
break;
}
Data = new byte[PacketLength];
int Offset = 0;
do
{
int BytesRead = Stream.Read(Data, Offset, PacketLength);
if (BytesRead == 0)
{
break;
}
Offset += BytesRead;
PacketLength -= BytesRead;
} while (PacketLength > 0);
if (PacketLength != 0)
{
break;
}
}
catch (IOException) { break; }
try
{
if (State == EncryptionState.Encrypted)
{
MessageReceived(Encryptor.Decrypt(Data));
}
else
{
MessageType Type = MessageType.Invalid;
if (Data.Length > 3)
{
Type = (MessageType)(ToUInt32(Data, 0) & ~0x80000000U);
}
if (State == EncryptionState.Connected && Type == MessageType.ChannelEncrypt)
{
RawMessage <ChannelEncrypt> Message = new RawMessage <ChannelEncrypt>(Data);
if (Message.Payload.Length >= 16)
{
RawMessage <ChannelEncrypt> Response = new RawMessage <ChannelEncrypt>(MessageType.ChannelEncryptResponse);
byte[] Challenge = Message.Payload, EncryptedBlob, SessionKey = new byte[32];
using (RandomNumberGenerator RNG = RandomNumberGenerator.Create())
RNG.GetBytes(SessionKey);
using (RSA RSA = RSA.Create())
{
RSA.ImportParameters(Parameters);
byte[] BlobToEncrypt = new byte[32 + Challenge.Length];
Copy(SessionKey, BlobToEncrypt, 32);
Copy(Challenge, 0, BlobToEncrypt, 32, Challenge.Length);
EncryptedBlob = RSA.Encrypt(BlobToEncrypt, RSAEncryptionPadding.OaepSHA1);
}
byte[] CRCHash;
using (CRC32 CRC = new CRC32())
CRCHash = CRC.ComputeHash(EncryptedBlob);
int Length = EncryptedBlob.Length;
Response.Payload = new byte[Length + 8];
Copy(EncryptedBlob, Response.Payload, Length);
Copy(CRCHash, 0, Response.Payload, Length, 4);
Encryptor = new EncryptionFilter(SessionKey);
State = EncryptionState.Challenged;
Send(Response.Serialize());
}
else
{
Disconnect(false);
}
}
else if (State == EncryptionState.Challenged && Type == MessageType.ChannelEncryptResult)
{
if (new RawMessage <ChannelEncryptResult>(Data).Body.Success)
{
State = EncryptionState.Encrypted;
Log($"Established encrypted TCP connection to {EndpointAddress}");
Connected?.Invoke();
}
else
{
Disconnect(false);
}
}
else
{
Disconnect(false);
}
}
}
catch { }
}
bool UserInitiated = Cancellator.IsCancellationRequested;
if (UserInitiated)
{
Shutdown();
}
Release(UserInitiated);
}