using System; using System.Collections.Generic; using System.IO; namespace Org.BouncyCastle.Tls { public abstract class TlsSrtpUtilities { public static void AddUseSrtpExtension(IDictionary<int, byte[]> extensions, UseSrtpData useSrtpData) { extensions[14] = CreateUseSrtpExtension(useSrtpData); } public static UseSrtpData GetUseSrtpExtension(IDictionary<int, byte[]> extensions) { byte[] extensionData = TlsUtilities.GetExtensionData(extensions, 14); if (extensionData != null) return ReadUseSrtpExtension(extensionData); return null; } public static byte[] CreateUseSrtpExtension(UseSrtpData useSrtpData) { if (useSrtpData == null) throw new ArgumentNullException("useSrtpData"); MemoryStream memoryStream = new MemoryStream(); TlsUtilities.WriteUint16ArrayWithUint16Length(useSrtpData.ProtectionProfiles, memoryStream); TlsUtilities.WriteOpaque8(useSrtpData.Mki, memoryStream); return memoryStream.ToArray(); } public static UseSrtpData ReadUseSrtpExtension(byte[] extensionData) { if (extensionData == null) throw new ArgumentNullException("extensionData"); MemoryStream memoryStream = new MemoryStream(extensionData, false); int num = TlsUtilities.ReadUint16(memoryStream); if (num < 2 || (num & 1) != 0) throw new TlsFatalAlert(50); int[] protectionProfiles = TlsUtilities.ReadUint16Array(num / 2, memoryStream); byte[] mki = TlsUtilities.ReadOpaque8(memoryStream); TlsProtocol.AssertEmpty(memoryStream); return new UseSrtpData(protectionProfiles, mki); } } }