/**
* Async callback for data sent by client
*/
private void ClientDataCallback(IAsyncResult state)
{
try {
WsCallbackState cs = (WsCallbackState)state.AsyncState;
NetworkStream stream = cs.client.GetStream();
int bytes = stream.EndRead(state);
if (bytes > 0)
{
byte[] frames = new byte[bytes];
Array.Copy(cs.buffer, 0, frames, 0, bytes);
bool closed = false;
try {
// decode client message
WsDataFrame frame = FramesToMessage(frames);
if (frame.opcode == 0x8) // close frame
{
int close_code = 0;
if (frame.payload.Length == 2)
{
close_code = ((frame.payload[0] & 0xff) << 8) + (frame.payload[1] & 0xff);
}
byte[] close_msg = WsDataFrame.CloseFrame(close_code);
stream.Write(close_msg, 0, close_msg.Length);
cs.client.Close();
_clients.Remove(cs.client);
closed = true;
}
else if (frame.opcode == 0x9) // ping frame
{
byte[] pong_msg = WsDataFrame.PongFrame(frame.payload);
stream.Write(pong_msg, 0, pong_msg.Length);
}
} catch (WsFatalClientException ex) {
// client did something wrong. kill connection
if (_verbose > 0)
{
System.Console.WriteLine(ex);
}
cs.client.Close();
_clients.Remove(cs.client);
closed = true;
} catch (Exception ex) {
if (_verbose > 0)
{
System.Console.WriteLine(ex);
}
}
if (!closed)
{
MonitorClient(cs.client);
}
}
else // zero-bytes read implies closed connection, I think
{
cs.client.Close();
_clients.Remove(cs.client);
}
} catch (Exception) {
}
}
private WsDataFrame FramesToMessage(byte[] frames)
{
if (frames.Length < 2)
{
throw new WsProtocolException("Invalid frame: too short (header)");
}
int opcode = frames[0] & 0xf;
int last_fragment = frames[0] & 0x80;
int masked = frames[1] & 0x80;
long length = frames[1] & 0x7f;
int data_starts = 6;
if (masked == 0)
{
throw new WsFatalClientException("Client data not masked");
}
byte[] mask_key = new byte[4];
if (length <= 125)
{
if (frames.Length < 6)
{
throw new WsProtocolException("Invalid frame: too short (mask)");
}
Array.Copy(frames, 2, mask_key, 0, 4);
}
else if (length == 126)
{
if (frames.Length < 8)
{
throw new WsProtocolException("Invalid frame: too short (mask)");
}
length = ((frames[2] << 8) & 0xff00) + (frames[3] & 0xff);
Array.Copy(frames, 4, mask_key, 0, 4);
data_starts = 8;
}
else if (length == 127)
{
if (frames.Length < 14)
{
throw new WsProtocolException("Invalid frame: too short (mask)");
}
length = ((frames[2] & 0xff) << 56)
+ ((frames[3] & 0xff) << 48)
+ ((frames[4] & 0xff) << 40)
+ ((frames[5] & 0xff) << 32)
+ ((frames[6] & 0xff) << 24)
+ ((frames[7] & 0xff) << 16)
+ ((frames[8] & 0xff) << 8)
+ (frames[9] & 0xff);
Array.Copy(frames, 10, mask_key, 0, 4);
data_starts = 14;
}
if (frames.Length < (data_starts + length))
{
throw new WsProtocolException("Invalid frame: too short (payload)");
}
byte[] payload = new byte[length];
for (int i = 0; i < length; i++)
{
payload[i] = (byte)(frames[i + data_starts] ^ mask_key[i % 4]);
}
if (last_fragment == 0)
{
byte[] remainder = new byte[frames.Length - (data_starts + length)];
Array.Copy(frames, data_starts + length, remainder, 0, remainder.Length);
WsDataFrame others = FramesToMessage(remainder);
byte[] full_payload = new byte[payload.Length + others.payload.Length];
Array.Copy(payload, 0, full_payload, 0, payload.Length);
Array.Copy(others.payload, 0, full_payload, payload.Length, others.payload.Length);
return(new WsDataFrame(opcode, full_payload));
}
else
{
return(new WsDataFrame(opcode, payload));
}
}