// This function will try to parse TLS hello frame and fill details in provided info structure.
// If frame was fully processed without any error, function returns true.
// Otherwise it returns false and info may have partial data.
// It is OK to call it again if more data becomes available.
// It is also possible to limit what information is processed.
// If callback delegate is provided, it will be called on ALL extensions.
public static bool TryGetFrameInfo(ReadOnlySpan <byte> frame, ref TlsFrameInfo info, ProcessingOptions options = ProcessingOptions.All, HelloExtensionCallback?callback = null)
{
const int HandshakeTypeOffset = 5;
if (frame.Length < HeaderSize)
{
return(false);
}
// This will not fail since we have enough data.
bool gotHeader = TryGetFrameHeader(frame, ref info.Header);
Debug.Assert(gotHeader);
info.SupportedVersions = info.Header.Version;
if (info.Header.Type == TlsContentType.Alert)
{
TlsAlertLevel level = default;
TlsAlertDescription description = default;
if (TryGetAlertInfo(frame, ref level, ref description))
{
info.AlertDescription = description;
return(true);
}
return(false);
}
if (info.Header.Type != TlsContentType.Handshake || frame.Length <= HandshakeTypeOffset)
{
return(false);
}
info.HandshakeType = (TlsHandshakeType)frame[HandshakeTypeOffset];
// Check if we have full frame.
bool isComplete = frame.Length >= HeaderSize + info.Header.Length;
#pragma warning disable SYSLIB0039 // TLS 1.0 and 1.1 are obsolete
if (((int)info.Header.Version >= (int)SslProtocols.Tls) &&
#pragma warning restore SYSLIB0039
(info.HandshakeType == TlsHandshakeType.ClientHello || info.HandshakeType == TlsHandshakeType.ServerHello))
{
if (!TryParseHelloFrame(frame.Slice(HeaderSize), ref info, options, callback))
{
isComplete = false;
}
}
return(isComplete);
}
// This function will parse TLS Alert message and it will return alert level and description.
public static bool TryGetAlertInfo(ReadOnlySpan <byte> frame, ref TlsAlertLevel level, ref TlsAlertDescription description)
{
if (frame.Length < 7 || frame[0] != (byte)TlsContentType.Alert)
{
return(false);
}
level = (TlsAlertLevel)frame[5];
description = (TlsAlertDescription)frame[6];
return(true);
}
// This function will try to parse TLS hello frame and fill details in provided info structure.
// If frame was fully processed without any error, function returns true.
// Otherwise it returns false and info may have partial data.
// It is OK to call it again if more data becomes available.
// It is also possible to limit what information is processed.
// If callback delegate is provided, it will be called on ALL extensions.
public static bool TryGetFrameInfo(ReadOnlySpan <byte> frame, ref TlsFrameInfo info, ProcessingOptions options = ProcessingOptions.All, HelloExtensionCallback?callback = null)
{
const int HandshakeTypeOffset = 5;
if (frame.Length < HeaderSize)
{
return(false);
}
// This will not fail since we have enough data.
bool gotHeader = TryGetFrameHeader(frame, ref info.Header);
Debug.Assert(gotHeader);
info.SupportedVersions = info.Header.Version;
#pragma warning disable CS0618 // Ssl2 and Ssl3 are obsolete
if (info.Header.Version == SslProtocols.Ssl2)
{
// This is safe. We would not get here if the length is too small.
info.SupportedVersions |= TlsMinorVersionToProtocol(frame[4]);
// We only recognize Unified ClientHello at the moment.
// This is needed to trigger certificate selection callback in SslStream.
info.HandshakeType = TlsHandshakeType.ClientHello;
// There is no more parsing for old protocols.
return(true);
}
#pragma warning restore CS0618
if (info.Header.Type == TlsContentType.Alert)
{
TlsAlertLevel level = default;
TlsAlertDescription description = default;
if (TryGetAlertInfo(frame, ref level, ref description))
{
info.AlertDescription = description;
return(true);
}
return(false);
}
if (info.Header.Type != TlsContentType.Handshake || frame.Length <= HandshakeTypeOffset)
{
return(false);
}
info.HandshakeType = (TlsHandshakeType)frame[HandshakeTypeOffset];
// Check if we have full frame.
bool isComplete = frame.Length >= HeaderSize + info.Header.Length;
if (((int)info.Header.Version >= (int)SslProtocols.Tls) &&
(info.HandshakeType == TlsHandshakeType.ClientHello || info.HandshakeType == TlsHandshakeType.ServerHello))
{
if (!TryParseHelloFrame(frame.Slice(HeaderSize), ref info, options, callback))
{
isComplete = false;
}
}
return(isComplete);
}