public void DecodePayload(byte[] buffer, int offset, Header frameHeader, out byte[] payload, out int payloadOffset, out int payloadCount)
{
payload = buffer;
payloadOffset = offset + frameHeader.Length;
payloadCount = frameHeader.PayloadLength;
if (frameHeader.IsMasked)
{
payload = new byte[payloadCount];
for (var i = 0; i < payloadCount; i++)
{
payload[i] = (byte)(buffer[payloadOffset + i] ^ buffer[offset + frameHeader.MaskingKeyOffset + i % MaskingKeyLength]);
}
payloadOffset = 0;
payloadCount = payload.Length;
}
// Payload data: (x+y) bytes
// Extension data: x bytes
// Application data: y bytes
// The "Extension data" is 0 bytes unless an extension has been
// negotiated. Any extension MUST specify the length of the
// "Extension data", or how that length may be calculated, and how
// the extension use MUST be negotiated during the opening handshake.
// If present, the "Extension data" is included in the total payload length.
if (this.NegotiatedExtensions != null)
{
byte[] bakedBuffer = null;
foreach (var extension in this.NegotiatedExtensions.Reverse().Select(e => e.Value))
{
if (bakedBuffer == null)
{
bakedBuffer = extension.ProcessIncomingMessagePayload(payload, payloadOffset, payloadCount);
}
else
{
bakedBuffer = extension.ProcessIncomingMessagePayload(bakedBuffer, 0, bakedBuffer.Length);
}
}
payload = bakedBuffer;
payloadOffset = 0;
payloadCount = payload.Length;
}
}
public bool TryDecodeFrameHeader(byte[] buffer, int offset, int count, out Header frameHeader)
{
frameHeader = DecodeFrameHeader(buffer, offset, count);
return frameHeader != null;
}
private Header DecodeFrameHeader(byte[] buffer, int offset, int count)
{
if (count < 2)
return null;
// parse fixed header
var header = new Header()
{
IsFIN = ((buffer[offset + 0] & 0x80) == 0x80),
IsRSV1 = ((buffer[offset + 0] & 0x40) == 0x40),
IsRSV2 = ((buffer[offset + 0] & 0x20) == 0x20),
IsRSV3 = ((buffer[offset + 0] & 0x10) == 0x10),
OpCode = (OpCode)(buffer[offset + 0] & 0x0f),
IsMasked = ((buffer[offset + 1] & 0x80) == 0x80),
PayloadLength = (buffer[offset + 1] & 0x7f),
Length = 2,
};
// parse extended payload length
if (header.PayloadLength >= 126)
{
if (header.PayloadLength == 126)
header.Length += 2;
else
header.Length += 8;
if (count < header.Length)
return null;
if (header.PayloadLength == 126)
{
header.PayloadLength = buffer[offset + 2] * 256 + buffer[offset + 3];
}
else
{
int totalLength = 0;
int level = 1;
for (int i = 7; i >= 0; i--)
{
totalLength += buffer[offset + i + 2] * level;
level *= 256;
}
header.PayloadLength = totalLength;
}
}
// parse masking key
if (header.IsMasked)
{
if (count < header.Length + MaskingKeyLength)
return null;
header.MaskingKeyOffset = header.Length;
header.Length += MaskingKeyLength;
}
return header;
}
private async Task HandlePingFrame(Header frameHeader, byte[] payload, int payloadOffset, int payloadCount)
{
if (!frameHeader.IsFIN)
{
throw new WebSocketException(string.Format(
"Server received unfinished frame [{0}] from remote [{1}].", frameHeader.OpCode, RemoteEndPoint));
}
// Upon receipt of a Ping frame, an endpoint MUST send a Pong frame in
// response, unless it already received a Close frame. It SHOULD
// respond with Pong frame as soon as is practical. Pong frames are
// discussed in Section 5.5.3.
//
// An endpoint MAY send a Ping frame any time after the connection is
// established and before the connection is closed.
//
// A Ping frame may serve either as a keep-alive or as a means to
// verify that the remote endpoint is still responsive.
var ping = Encoding.UTF8.GetString(payload, payloadOffset, payloadCount);
#if DEBUG
_log.DebugFormat("Session [{0}] received client side ping frame [{1}].", this, ping);
#endif
if (State == WebSocketState.Open)
{
// A Pong frame sent in response to a Ping frame must have identical
// "Application data" as found in the message body of the Ping frame being replied to.
var pong = new PongFrame(ping, false).ToArray(_frameBuilder);
await SendFrame(pong);
#if DEBUG
_log.DebugFormat("Session [{0}] sends server side pong frame [{1}].", this, ping);
#endif
}
}
private async Task HandlePongFrame(Header frameHeader, byte[] payload, int payloadOffset, int payloadCount)
{
if (!frameHeader.IsFIN)
{
throw new WebSocketException(string.Format(
"Server received unfinished frame [{0}] from remote [{1}].", frameHeader.OpCode, RemoteEndPoint));
}
// If an endpoint receives a Ping frame and has not yet sent Pong
// frame(s) in response to previous Ping frame(s), the endpoint MAY
// elect to send a Pong frame for only the most recently processed Ping frame.
//
// A Pong frame MAY be sent unsolicited. This serves as a
// unidirectional heartbeat. A response to an unsolicited Pong frame is not expected.
var pong = Encoding.UTF8.GetString(payload, payloadOffset, payloadCount);
StopKeepAliveTimeoutTimer();
#if DEBUG
_log.DebugFormat("Session [{0}] received client side pong frame [{1}].", this, pong);
#endif
await Task.CompletedTask;
}
private async Task HandleBinaryFrame(Header frameHeader, byte[] payload, int payloadOffset, int payloadCount)
{
if (frameHeader.IsFIN)
{
try
{
await _module.OnSessionBinaryReceived(this, payload, payloadOffset, payloadCount);
}
catch (Exception ex)
{
HandleUserSideError(ex);
}
}
else
{
try
{
await _module.OnSessionFragmentationStreamOpened(this, payload, payloadOffset, payloadCount);
}
catch (Exception ex)
{
HandleUserSideError(ex);
}
}
}
private async Task HandleCloseFrame(Header frameHeader, byte[] payload, int payloadOffset, int payloadCount)
{
if (!frameHeader.IsFIN)
{
throw new WebSocketException(string.Format(
"Server received unfinished frame [{0}] from remote [{1}].", frameHeader.OpCode, RemoteEndPoint));
}
if (payloadCount > 1)
{
var statusCode = payload[payloadOffset + 0] * 256 + payload[payloadOffset + 1];
var closeCode = (WebSocketCloseCode)statusCode;
var closeReason = string.Empty;
if (payloadCount > 2)
{
closeReason = Encoding.UTF8.GetString(payload, payloadOffset + 2, payloadCount - 2);
}
#if DEBUG
_log.DebugFormat("Session [{0}] received client side close frame [{1}] [{2}].", this, closeCode, closeReason);
#endif
// If an endpoint receives a Close frame and did not previously send a
// Close frame, the endpoint MUST send a Close frame in response. (When
// sending a Close frame in response, the endpoint typically echos the
// status code it received.) It SHOULD do so as soon as practical.
await Close(closeCode, closeReason);
}
else
{
#if DEBUG
_log.DebugFormat("Session [{0}] received client side close frame but no status code.", this);
#endif
await Close(WebSocketCloseCode.InvalidPayloadData);
}
}
private async Task HandleTextFrame(Header frameHeader, byte[] payload, int payloadOffset, int payloadCount)
{
if (frameHeader.IsFIN)
{
try
{
var text = Encoding.UTF8.GetString(payload, payloadOffset, payloadCount);
await _module.OnSessionTextReceived(this, text);
}
catch (Exception ex)
{
HandleUserSideError(ex);
}
}
else
{
try
{
await _module.OnSessionFragmentationStreamOpened(this, payload, payloadOffset, payloadCount);
}
catch (Exception ex)
{
HandleUserSideError(ex);
}
}
}
private async Task HandleContinuationFrame(Header frameHeader, byte[] payload, int payloadOffset, int payloadCount)
{
if (!frameHeader.IsFIN)
{
try
{
await _module.OnSessionFragmentationStreamContinued(this, payload, payloadOffset, payloadCount);
}
catch (Exception ex)
{
HandleUserSideError(ex);
}
}
else
{
try
{
await _module.OnSessionFragmentationStreamClosed(this, payload, payloadOffset, payloadCount);
}
catch (Exception ex)
{
HandleUserSideError(ex);
}
}
}
public void DecodePayload(byte[] buffer, int offset, Header frameHeader, out byte[] payload, out int payloadOffset, out int payloadCount)
{
payload = buffer;
payloadOffset = offset + frameHeader.Length;
payloadCount = frameHeader.PayloadLength;
if (frameHeader.IsMasked)
{
payload = new byte[payloadCount];
for (var i = 0; i < payloadCount; i++)
{
payload[i] = (byte)(buffer[payloadOffset + i] ^ buffer[offset + frameHeader.MaskingKeyOffset + i % MaskingKeyLength]);
}
payloadOffset = 0;
payloadCount = payload.Length;
}
}
private void HandleBinaryFrame(Header frameHeader, byte[] payload, int payloadOffset, int payloadCount)
{
if (frameHeader.IsFIN)
{
try
{
RaiseServerBinaryReceived(payload, payloadOffset, payloadCount);
}
catch (Exception ex)
{
HandleUserSideError(ex);
}
}
else
{
throw new WebSocketException(string.Format(
"Client received continuation opcode [{0}] from remote [{1}] but not supported.", frameHeader.OpCode, RemoteEndPoint));
}
}
private void HandleContinuationFrame(Header frameHeader, byte[] payload, int payloadOffset, int payloadCount)
{
throw new WebSocketException(string.Format(
"Client received continuation opcode [{0}] from remote [{1}] but not supported.", frameHeader.OpCode, RemoteEndPoint));
}
