init commit

output/Libraries/BouncyCastle.Crypto/Org/BouncyCastle/Crypto/Tls/DtlsProtocol.cs

@@ -0,0 +1,79 @@
+using System;
+using System.Collections;
+using System.IO;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Tls;
+
+public abstract class DtlsProtocol
+{
+	protected readonly SecureRandom mSecureRandom;
+
+	protected DtlsProtocol(SecureRandom secureRandom)
+	{
+		if (secureRandom == null)
+		{
+			throw new ArgumentNullException("secureRandom");
+		}
+		mSecureRandom = secureRandom;
+	}
+
+	protected virtual void ProcessFinished(byte[] body, byte[] expected_verify_data)
+	{
+		MemoryStream memoryStream = new MemoryStream(body, writable: false);
+		byte[] b = TlsUtilities.ReadFully(expected_verify_data.Length, memoryStream);
+		TlsProtocol.AssertEmpty(memoryStream);
+		if (!Arrays.ConstantTimeAreEqual(expected_verify_data, b))
+		{
+			throw new TlsFatalAlert(40);
+		}
+	}
+
+	internal static void ApplyMaxFragmentLengthExtension(DtlsRecordLayer recordLayer, short maxFragmentLength)
+	{
+		if (maxFragmentLength >= 0)
+		{
+			if (!MaxFragmentLength.IsValid((byte)maxFragmentLength))
+			{
+				throw new TlsFatalAlert(80);
+			}
+			int plaintextLimit = 1 << 8 + maxFragmentLength;
+			recordLayer.SetPlaintextLimit(plaintextLimit);
+		}
+	}
+
+	protected static short EvaluateMaxFragmentLengthExtension(bool resumedSession, IDictionary clientExtensions, IDictionary serverExtensions, byte alertDescription)
+	{
+		short maxFragmentLengthExtension = TlsExtensionsUtilities.GetMaxFragmentLengthExtension(serverExtensions);
+		if (maxFragmentLengthExtension >= 0 && (!MaxFragmentLength.IsValid((byte)maxFragmentLengthExtension) || (!resumedSession && maxFragmentLengthExtension != TlsExtensionsUtilities.GetMaxFragmentLengthExtension(clientExtensions))))
+		{
+			throw new TlsFatalAlert(alertDescription);
+		}
+		return maxFragmentLengthExtension;
+	}
+
+	protected static byte[] GenerateCertificate(Certificate certificate)
+	{
+		MemoryStream memoryStream = new MemoryStream();
+		certificate.Encode(memoryStream);
+		return memoryStream.ToArray();
+	}
+
+	protected static byte[] GenerateSupplementalData(IList supplementalData)
+	{
+		MemoryStream memoryStream = new MemoryStream();
+		TlsProtocol.WriteSupplementalData(memoryStream, supplementalData);
+		return memoryStream.ToArray();
+	}
+
+	protected static void ValidateSelectedCipherSuite(int selectedCipherSuite, byte alertDescription)
+	{
+		switch (TlsUtilities.GetEncryptionAlgorithm(selectedCipherSuite))
+		{
+		case 1:
+		case 2:
+			throw new TlsFatalAlert(alertDescription);
+		}
+	}
+}