| public Decode ( byte buffer, int offset, int length ) : void | ||
| buffer | byte | |
| offset | int | |
| length | int | |
| return | void | |
private void EndCheckEncryption(IAsyncResult result)
{
var id = (PeerId) result.AsyncState;
try
{
byte[] initialData;
EncryptorFactory.EndCheckEncryption(result, out initialData);
if (initialData != null && initialData.Length == HandshakeMessage.HandshakeLength)
{
var message = new HandshakeMessage();
message.Decode(initialData, 0, initialData.Length);
HandleHandshake(id, message);
}
else if (initialData == null || initialData.Length > 0)
{
throw new Exception("Argh. I can't handle this scenario. It also shouldn't happen. Ever.");
}
else
{
PeerIO.EnqueueReceiveHandshake(id.Connection, id.Decryptor, _handshakeReceivedCallback, id);
}
}
catch
{
id.Connection.Dispose();
}
}
private static void HandshakeReceived(bool successful, int transferred, object state)
{
var data = (ReceiveMessageState) state;
PeerMessage message = null;
if (successful)
{
data.Decryptor.Decrypt(data.Buffer, 0, transferred);
message = new HandshakeMessage();
message.Decode(data.Buffer, 0, transferred);
}
data.Callback(successful, message, data.State);
ClientEngine.BufferManager.FreeBuffer(data.Buffer);
ReceiveCache.Enqueue(data);
}
private static void HandshakeReceived(bool succeeded, int count, object state)
{
var result = (EncryptorAsyncResult) state;
var connection = result.Id.Connection;
try
{
if (!succeeded)
throw new EncryptionException("Couldn't receive the handshake");
result.Available += count;
var message = new HandshakeMessage();
message.Decode(result.Buffer, 0, result.Buffer.Length);
var valid = message.ProtocolString == VersionInfo.ProtocolStringV100;
var usable = CheckRc4(result.Id);
var canUseRc4 = Toolbox.HasEncryption(usable, EncryptionTypes.RC4Header) ||
Toolbox.HasEncryption(usable, EncryptionTypes.RC4Full);
// If encryption is disabled and we received an invalid handshake - abort!
if (valid)
{
result.InitialData = result.Buffer;
result.Complete();
return;
}
if (!canUseRc4)
{
result.Complete(new EncryptionException("Invalid handshake received and no decryption works"));
return;
}
// The data we just received was part of an encrypted handshake and was *not* the BitTorrent handshake
result.EncSocket = new PeerBEncryption(result.SKeys, EncryptionTypes.All);
result.EncSocket.BeginHandshake(connection, result.Buffer, 0, result.Buffer.Length,
CompletedEncryptedHandshakeCallback, result);
}
catch (Exception ex)
{
result.Complete(ex);
}
}