internal WebSocketFrame(
Fin fin, Opcode opcode, Mask mask, PayloadData payload, bool compressed)
{
_fin = fin;
_rsv1 = isData(opcode) && compressed ? Rsv.On : Rsv.Off;
_rsv2 = Rsv.Off;
_rsv3 = Rsv.Off;
_opcode = opcode;
_mask = mask;
var len = payload.Length;
if (len < 126)
{
_payloadLength = (byte)len;
_extPayloadLength = new byte[0];
}
else if (len < 0x010000)
{
_payloadLength = (byte)126;
_extPayloadLength = ((ushort)len).ToByteArrayInternally(ByteOrder.Big);
}
else
{
_payloadLength = (byte)127;
_extPayloadLength = len.ToByteArrayInternally(ByteOrder.Big);
}
if (mask == Mask.Mask)
{
_maskingKey = createMaskingKey();
payload.Mask(_maskingKey);
}
else
{
_maskingKey = new byte[0];
}
_payloadData = payload;
}
private static async Task <WebSocketFrame> ReadAsync(byte[] header, Stream stream, bool unmask)
{
/* Header */
// FIN
var fin = (header[0] & 0x80) == 0x80 ? Fin.Final : Fin.More;
// RSV1
var rsv1 = (header[0] & 0x40) == 0x40 ? Rsv.On : Rsv.Off;
// RSV2
var rsv2 = (header[0] & 0x20) == 0x20 ? Rsv.On : Rsv.Off;
// RSV3
var rsv3 = (header[0] & 0x10) == 0x10 ? Rsv.On : Rsv.Off;
// Opcode
var opcode = (Opcode)(header[0] & 0x0f);
// MASK
var mask = (header[1] & 0x80) == 0x80 ? Mask.Mask : Mask.Unmask;
// Payload Length
var payloadLen = (byte)(header[1] & 0x7f);
// Check if correct frame.
var incorrect = isControl(opcode) && fin == Fin.More
? "A control frame is fragmented."
: !isData(opcode) && rsv1 == Rsv.On
? "A non data frame is compressed."
: null;
if (incorrect != null)
{
throw new WebSocketException(CloseStatusCode.IncorrectData, incorrect);
}
// Check if consistent frame.
if (isControl(opcode) && payloadLen > 125)
{
throw new WebSocketException(
CloseStatusCode.InconsistentData,
"The length of payload data of a control frame is greater than 125 bytes.");
}
var frame = new WebSocketFrame();
frame._fin = fin;
frame._rsv1 = rsv1;
frame._rsv2 = rsv2;
frame._rsv3 = rsv3;
frame._opcode = opcode;
frame._mask = mask;
frame._payloadLength = payloadLen;
/* Extended Payload Length */
var size = payloadLen < 126
? 0
: payloadLen == 126
? 2
: 8;
var extPayloadLen = size > 0 ? await stream.ReadBytesAsync(size).ConfigureAwait(false) : Array.Empty <byte>();
if (size > 0 && extPayloadLen.Length != size)
{
throw new WebSocketException(
"The 'Extended Payload Length' of a frame cannot be read from the data source.");
}
frame._extPayloadLength = extPayloadLen;
/* Masking Key */
var masked = mask == Mask.Mask;
var maskingKey = masked ? await stream.ReadBytesAsync(4).ConfigureAwait(false) : Array.Empty <byte>();
if (masked && maskingKey.Length != 4)
{
throw new WebSocketException(
"The 'Masking Key' of a frame cannot be read from the data source.");
}
frame._maskingKey = maskingKey;
/* Payload Data */
ulong len = payloadLen < 126
? payloadLen
: payloadLen == 126
? extPayloadLen.ToUInt16(ByteOrder.Big)
: extPayloadLen.ToUInt64(ByteOrder.Big);
byte[] data = null;
if (len > 0)
{
// Check if allowable payload data length.
if (payloadLen > 126 && len > PayloadData.MaxLength)
{
throw new WebSocketException(
CloseStatusCode.TooBig,
"The length of 'Payload Data' of a frame is greater than the allowable length.");
}
data = payloadLen > 126
? await stream.ReadBytesAsync((long)len, 1024).ConfigureAwait(false)
: await stream.ReadBytesAsync((int)len).ConfigureAwait(false);
//if (data.LongLength != (long)len)
// throw new WebSocketException(
// "The 'Payload Data' of a frame cannot be read from the data source.");
}
else
{
data = Array.Empty <byte>();
}
var payload = new PayloadData(data, masked);
if (masked && unmask)
{
payload.Mask(maskingKey);
frame._mask = Mask.Unmask;
frame._maskingKey = Array.Empty <byte>();
}
frame._payloadData = payload;
return(frame);
}
