public static bool TryGetFrameHeader(ReadOnlySpan <byte> frame, ref TlsFrameHeader header)
{
bool result = frame.Length > 4;
if (frame.Length >= 1)
{
header.Type = (TlsContentType)frame[0];
if (frame.Length >= 3)
{
// SSLv3, TLS or later
if (frame[1] == 3)
{
if (frame.Length > 4)
{
header.Length = ((frame[3] << 8) | frame[4]);
}
header.Version = TlsMinorVersionToProtocol(frame[2]);
}
else
{
header.Length = -1;
header.Version = SslProtocols.None;
}
}
}
return(result);
}
public static bool TryGetFrameHeader(ReadOnlySpan <byte> frame, ref TlsFrameHeader header)
{
bool result = frame.Length > 4;
if (frame.Length >= 1)
{
header.Type = (TlsContentType)frame[0];
if (frame.Length > 4)
{
// SSLv3, TLS or later
if (frame[1] == 3)
{
header.Length = ((frame[3] << 8) | frame[4]);
header.Version = TlsMinorVersionToProtocol(frame[2]);
return(true);
}
// May be SSL3/TLS frame wrapped in unified header.
else if (frame[2] == (byte)TlsHandshakeType.ClientHello &&
frame[3] == 3) // SSL3 or above
{
int length;
if ((frame[0] & 0x80) != 0)
{
// Two bytes
length = (((frame[0] & 0x7f) << 8) | frame[1]) + 2;
}
else
{
// Three bytes
length = (((frame[0] & 0x3f) << 8) | frame[1]) + 3;
}
// max frame for SSLv2 is 32767.
// However, we expect something reasonable for initial HELLO
// We don't have enough logic to verify full validity,
// the limits bellow are queses.
if (length > 20 && length < 1000)
{
#pragma warning disable CS0618 // Ssl2 and Ssl3 are obsolete
header.Version = SslProtocols.Ssl2;
#pragma warning restore CS0618
header.Length = length;
header.Type = TlsContentType.Handshake;
return(true);
}
}
}
}
header.Length = -1;
header.Version = SslProtocols.None;
return(result);
}
