using Org.BouncyCastle.Utilities; using System.Collections.Generic; using System.IO; namespace Org.BouncyCastle.Tls { public abstract class DtlsProtocol { internal DtlsProtocol() { } internal virtual void ProcessFinished(byte[] body, byte[] expected_verify_data) { MemoryStream memoryStream = new MemoryStream(body, false); byte[] b = TlsUtilities.ReadFully(expected_verify_data.Length, memoryStream); TlsProtocol.AssertEmpty(memoryStream); if (!Arrays.FixedTimeEquals(expected_verify_data, b)) throw new TlsFatalAlert(40); } internal static void ApplyMaxFragmentLengthExtension(DtlsRecordLayer recordLayer, short maxFragmentLength) { if (maxFragmentLength >= 0) { if (!MaxFragmentLength.IsValid(maxFragmentLength)) throw new TlsFatalAlert(80); int plaintextLimit = 1 << 8 + maxFragmentLength; recordLayer.SetPlaintextLimit(plaintextLimit); } } internal static byte[] GenerateCertificate(TlsContext context, Certificate certificate, Stream endPointHash) { MemoryStream memoryStream = new MemoryStream(); certificate.Encode(context, memoryStream, endPointHash); return memoryStream.ToArray(); } internal static byte[] GenerateSupplementalData(IList<SupplementalDataEntry> supplementalData) { MemoryStream memoryStream = new MemoryStream(); TlsProtocol.WriteSupplementalData(memoryStream, supplementalData); return memoryStream.ToArray(); } internal static void SendCertificateMessage(TlsContext context, DtlsReliableHandshake handshake, Certificate certificate, Stream endPointHash) { SecurityParameters securityParameters = context.SecurityParameters; if (securityParameters.LocalCertificate != null) throw new TlsFatalAlert(80); if (certificate == null) certificate = Certificate.EmptyChain; byte[] body = GenerateCertificate(context, certificate, endPointHash); handshake.SendMessage(11, body); securityParameters.m_localCertificate = certificate; } internal static int ValidateSelectedCipherSuite(int selectedCipherSuite, short alertDescription) { int encryptionAlgorithm = TlsUtilities.GetEncryptionAlgorithm(selectedCipherSuite); if (encryptionAlgorithm == -1 || (uint)(encryptionAlgorithm - 1) <= 1) throw new TlsFatalAlert(alertDescription); return selectedCipherSuite; } } }