/// <summary>
/// Handles an incoming connection.
/// If incoming connections are allowed,
/// the client is added to the clients list
/// and triggers the client connected event.
/// Else, the connection blocked event is
/// triggered.
/// </summary>
private void handleIncomingConnection(IAsyncResult result)
{
try
{
Socket oldSocket = (Socket)result.AsyncState;
if (acceptIncomingConnections)
{
Socket newSocket = oldSocket.EndAccept(result);
uint clientID = (uint)clients.Count + 1;
Client client = new Client(clientID, (IPEndPoint)newSocket.RemoteEndPoint);
clients.Add(newSocket, client);
// Start negotiation
sendBytesToSocket(newSocket, Negotiation.Do(Negotiation.Operations.Echo));
sendBytesToSocket(newSocket, Negotiation.Do(Negotiation.Operations.RemoteFlowControl));
sendBytesToSocket(newSocket, Negotiation.Will(Negotiation.Operations.Echo));
sendBytesToSocket(newSocket, Negotiation.Will(Negotiation.Operations.SuppressGoAhead));
sendBytesToSocket(newSocket, Negotiation.Will(Negotiation.Operations.BinaryTransmission));
sendBytesToSocket(newSocket, Negotiation.Do(Negotiation.Operations.NegotiateAboutWindowSize));
sendBytesToSocket(newSocket, Negotiation.Do(Negotiation.Operations.TerminalType));
client.resetReceivedData();
ClientConnected(client);
serverSocket.BeginAccept(new AsyncCallback(handleIncomingConnection), serverSocket);
}
else
{
ConnectionBlocked((IPEndPoint)oldSocket.RemoteEndPoint);
}
}
catch { }
}
/// <summary>
/// Receives and processes data from a socket.
/// It triggers the message received event in
/// case the client pressed the return key.
/// </summary>
private void receiveData(IAsyncResult result)
{
try
{
Socket clientSocket = (Socket)result.AsyncState;
Client client = getClientBySocket(clientSocket);
int bytesReceived = clientSocket.EndReceive(result);
if (bytesReceived == 0)
{
closeSocket(clientSocket);
ClientDisconnected(client);
serverSocket.BeginAccept(new AsyncCallback(handleIncomingConnection), serverSocket);
}
else if (data[0] == (byte)Negotiation.Tokens.IAC)
{
// Negotiation
int offset = 0;
while (offset < bytesReceived)
{
Negotiation.HandleBinary(data, offset, client);
Negotiation.HandleWindowSize(data, offset, client);
if (Negotiation.ClientWillTerminalType(data, offset))
{
sendBytesToSocket(clientSocket, Negotiation.AskForTerminalType());
}
if (Negotiation.HandleTerminalType(data, offset, client))
{
sendBytesToSocket(clientSocket, Negotiation.AskForTerminalType());
}
while (++offset < bytesReceived)
{
if (data[offset] == (byte)Negotiation.Tokens.IAC)
{
break;
}
}
}
clientSocket.BeginReceive(data, 0, dataSize, SocketFlags.None, new AsyncCallback(receiveData), clientSocket);
}
else if (data[0] < 0xF0)
{
string receivedData = client.receivedData;
client.lastActivity = DateTime.Now;
// 0x2E = '.', 0x0D = carriage return, 0x0A = new line
if ((data[0] == 0x2E && data[1] == 0x0D && receivedData.Length == 0) ||
(data[0] == 0x0D && data[1] == 0x0A) || data[0] == 0x0D || data[0] == 0x0A)
{
//sendMessageToSocket(clientSocket, "\u001B[1J\u001B[H");
MessageReceived(client, client.receivedData);
client.resetReceivedData();
}
else
{
// 0x08 => backspace character
if (data[0] == 0x08)
{
if (receivedData.Length > 0)
{
client.removeLastCharacterReceived();
sendBytesToSocket(clientSocket, new byte[] { 0x08, 0x20, 0x08 });
}
else
{
clientSocket.BeginReceive(data, 0, dataSize, SocketFlags.None, new AsyncCallback(receiveData), clientSocket);
}
}
// 0x7F => delete character
else if (data[0] == 0x7F)
{
clientSocket.BeginReceive(data, 0, dataSize, SocketFlags.None, new AsyncCallback(receiveData), clientSocket);
}
else if (data[0] < 0x20)
{
ControlCharReceived(client, data, bytesReceived);
}
else
{
client.appendReceivedData(Encoding.ASCII.GetString(data, 0, bytesReceived));
// Echo back the received character
// if client is not writing any password
if (client.inputMode != EInputMode.PasswordMode)
{
sendBytesToSocket(clientSocket, new byte[] { data[0] });
}
// Echo back asterisks if client is
// writing a password
else
{
sendMessageToSocket(clientSocket, "*");
}
clientSocket.BeginReceive(data, 0, dataSize, SocketFlags.None, new AsyncCallback(receiveData), clientSocket);
}
}
}
else
{
clientSocket.BeginReceive(data, 0, dataSize, SocketFlags.None, new AsyncCallback(receiveData), clientSocket);
}
}
catch { }
}
