System.Net.SSPIWrapper.QueryContextAttributes C# (CSharp) Method

        public static object QueryContextAttributes(SSPIInterface secModule, SafeDeleteContext securityContext, Interop.SspiCli.ContextAttribute contextAttribute, out int errorCode)
        {
            if (NetEventSource.IsEnabled) NetEventSource.Enter(null, contextAttribute);

            int nativeBlockSize = IntPtr.Size;
            Type handleType = null;

            switch (contextAttribute)
            {
                case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_SIZES:
                    nativeBlockSize = SecPkgContext_Sizes.SizeOf;
                    break;
                case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_STREAM_SIZES:
                    nativeBlockSize = SecPkgContext_StreamSizes.SizeOf;
                    break;

                case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_NAMES:
                    handleType = typeof(SafeFreeContextBuffer);
                    break;

                case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_PACKAGE_INFO:
                    handleType = typeof(SafeFreeContextBuffer);
                    break;

                case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_NEGOTIATION_INFO:
                    handleType = typeof(SafeFreeContextBuffer);
                    nativeBlockSize = Marshal.SizeOf<SecPkgContext_NegotiationInfoW>();
                    break;

                case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_CLIENT_SPECIFIED_TARGET:
                    handleType = typeof(SafeFreeContextBuffer);
                    break;

                case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_REMOTE_CERT_CONTEXT:
                    handleType = typeof(SafeFreeCertContext);
                    break;

                case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_LOCAL_CERT_CONTEXT:
                    handleType = typeof(SafeFreeCertContext);
                    break;

                case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_ISSUER_LIST_EX:
                    nativeBlockSize = Marshal.SizeOf<Interop.SspiCli.SecPkgContext_IssuerListInfoEx>();
                    handleType = typeof(SafeFreeContextBuffer);
                    break;

                case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_CONNECTION_INFO:
                    nativeBlockSize = Marshal.SizeOf<SecPkgContext_ConnectionInfo>();
                    break;

                default:
                    throw new ArgumentException(SR.Format(SR.net_invalid_enum, nameof(contextAttribute)), nameof(contextAttribute));
            }

            SafeHandle sspiHandle = null;
            object attribute = null;

            try
            {
                var nativeBuffer = new byte[nativeBlockSize];
                errorCode = secModule.QueryContextAttributes(securityContext, contextAttribute, nativeBuffer, handleType, out sspiHandle);
                if (errorCode != 0)
                {
                    if (NetEventSource.IsEnabled) NetEventSource.Exit(null, $"ERROR = {ErrorDescription(errorCode)}");
                    return null;
                }

                switch (contextAttribute)
                {
                    case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_SIZES:
                        attribute = new SecPkgContext_Sizes(nativeBuffer);
                        break;

                    case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_STREAM_SIZES:
                        attribute = new SecPkgContext_StreamSizes(nativeBuffer);
                        break;

                    case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_NAMES:
                        attribute = Marshal.PtrToStringUni(sspiHandle.DangerousGetHandle());
                        break;

                    case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_PACKAGE_INFO:
                        attribute = new SecurityPackageInfoClass(sspiHandle, 0);
                        break;

                    case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_NEGOTIATION_INFO:
                        unsafe
                        {
                            fixed (void* ptr = nativeBuffer)
                            {
                                attribute = new NegotiationInfoClass(sspiHandle, Marshal.ReadInt32(new IntPtr(ptr), SecPkgContext_NegotiationInfoW.NegotiationStateOffest));
                            }
                        }
                        break;

                    case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_CLIENT_SPECIFIED_TARGET:
                        attribute = Marshal.PtrToStringUni(sspiHandle.DangerousGetHandle());
                        break;

                    case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_LOCAL_CERT_CONTEXT:
                    // Fall-through to RemoteCertificate is intentional.
                    case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_REMOTE_CERT_CONTEXT:
                        attribute = sspiHandle;
                        sspiHandle = null;
                        break;

                    case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_ISSUER_LIST_EX:
                        attribute = new Interop.SspiCli.SecPkgContext_IssuerListInfoEx(sspiHandle, nativeBuffer);
                        sspiHandle = null;
                        break;

                    case Interop.SspiCli.ContextAttribute.SECPKG_ATTR_CONNECTION_INFO:
                        attribute = new SecPkgContext_ConnectionInfo(nativeBuffer);
                        break;
                    default:
                        // Will return null.
                        break;
                }
            }
            finally
            {
                if (sspiHandle != null)
                {
                    sspiHandle.Dispose();
                }
            }

            if (NetEventSource.IsEnabled) NetEventSource.Exit(null, attribute);
            return attribute;
        }

 public static void QueryContextStreamSizes(SafeDeleteContext securityContext, out StreamSizes streamSizes)
 {
     streamSizes = SSPIWrapper.QueryContextAttributes(
         GlobalSSPI.SSPISecureChannel,
         securityContext,
         Interop.SspiCli.ContextAttribute.StreamSizes) as StreamSizes;
 }