Initial encryption support

src/Discord.Net.Net45/Discord.Net.csproj

@@ -62,6 +62,9 @@
     <Content Include="lib\libopus.so">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
+    <Content Include="lib\libsodium.dll">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
     <Content Include="lib\opus.dll">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
@@ -101,6 +104,9 @@
     <Compile Include="..\Discord.Net\Audio\OpusEncoder.cs">
       <Link>Audio\OpusEncoder.cs</Link>
     </Compile>
+    <Compile Include="..\Discord.Net\Audio\Sodium.cs">
+      <Link>Audio\Sodium.cs</Link>
+    </Compile>
     <Compile Include="..\Discord.Net\Collections\AsyncCollection.cs">
       <Link>Collections\AsyncCollection.cs</Link>
     </Compile>

src/Discord.Net/Audio/Opus.cs

@@ -3,7 +3,7 @@ using System.Runtime.InteropServices;
 
 namespace Discord.Audio
 {
-	internal unsafe class Opus
+	internal static unsafe class Opus
 	{
 		[DllImport("lib/opus", EntryPoint = "opus_encoder_create", CallingConvention = CallingConvention.Cdecl)]
 		public static extern IntPtr CreateEncoder(int Fs, int channels, int application, out Error error);

src/Discord.Net/Audio/Sodium.cs

@@ -0,0 +1,15 @@
+using System.Runtime.InteropServices;
+
+namespace Discord.Audio
+{
+    internal static class Sodium
+    {
+		[DllImport("lib/libsodium", EntryPoint = "crypto_stream_xor", CallingConvention = CallingConvention.Cdecl)]
+		private static extern int StreamXOR(byte[] output, byte[] msg, long msgLength, byte[] nonce, byte[] secret);
+
+		public static int Encrypt(byte[] buffer, int inputLength, byte[] output, byte[] nonce, byte[] secret)
+		{
+			return StreamXOR(output, buffer, inputLength, nonce, secret);
+		}
+	}
+}

src/Discord.Net/DiscordClientConfig.cs

@@ -4,7 +4,7 @@ namespace Discord
 {
 	public class DiscordClientConfig
 	{
-		/// <summary> Specifies the minimum log level severity that will be sent to the LogMessage event. Warning: setting this to verbose will hinder performance but should help investigate any internal issues. </summary>
+		/// <summary> Specifies the minimum log level severity that will be sent to the LogMessage event. Warning: setting this to debug will really hurt performance but should help investigate any internal issues. </summary>
 		public LogMessageSeverity LogLevel { get { return _logLevel; } set { SetValue(ref _logLevel, value); } }
 		private LogMessageSeverity _logLevel = LogMessageSeverity.Info;
 
@@ -36,8 +36,12 @@ namespace Discord
 		/// <summary> (Experimental) Enables the voice websocket and UDP client. This option requires the opus .dll or .so be in the local lib/ folder. </summary>
 		public bool EnableVoice { get { return _enableVoice; } set { SetValue(ref _enableVoice, value); } }
 		private bool _enableVoice = false;
+		/// <summary> (Experimental) Enables the voice websocket and UDP client. This option requires the libsodium .dll or .so be in the local lib/ folder. </summary>
+		public bool EnableVoiceEncryption { get { return _enableVoiceEncryption; } set { SetValue(ref _enableVoiceEncryption, value); } }
+		private bool _enableVoiceEncryption = false;
 #else
 		internal bool EnableVoice => false;
+		internal bool EnableVoiceEncryption => false;
 #endif
 		/// <summary> (Experimental) Enables or disables the internal message queue. This will allow SendMessage to return immediately and handle messages internally. Messages will set the IsQueued and HasFailed properties to show their progress. </summary>
 		public bool UseMessageQueue { get { return _useMessageQueue; } set { SetValue(ref _useMessageQueue, value); } }

src/Discord.Net/WebSockets/Voice/VoiceWebSocket.cs

@@ -33,7 +33,7 @@ namespace Discord.WebSockets.Voice
 		private byte[] _secretKey;
 		private ushort _sequence;
 		private byte[] _encodingBuffer;
-		private string _serverId, _userId, _sessionId, _token;
+		private string _serverId, _userId, _sessionId, _token, _encryptionMode;
 
 #if USE_THREAD
 		private Thread _sendThread;
@@ -213,12 +213,18 @@ namespace Discord.WebSockets.Voice
 					Stopwatch sw = Stopwatch.StartNew();
 
 					byte[] rtpPacket = new byte[_encodingBuffer.Length + 12];
+					byte[] nonce = null;
 					rtpPacket[0] = 0x80; //Flags;
 					rtpPacket[1] = 0x78; //Payload Type
 					rtpPacket[8] = (byte)((_ssrc >> 24) & 0xFF);
 					rtpPacket[9] = (byte)((_ssrc >> 16) & 0xFF);
 					rtpPacket[10] = (byte)((_ssrc >> 8) & 0xFF);
 					rtpPacket[11] = (byte)((_ssrc >> 0) & 0xFF);
+					if (_isEncrypted)
+					{
+						nonce = new byte[24];
+						Buffer.BlockCopy(rtpPacket, 0, nonce, 0, 12);
+					}
 
 					while (!cancelToken.IsCancellationRequested)
 					{
@@ -238,6 +244,13 @@ namespace Discord.WebSockets.Voice
 										rtpPacket[5] = (byte)((timestamp >> 16) & 0xFF);
 										rtpPacket[6] = (byte)((timestamp >> 8) & 0xFF);
 										rtpPacket[7] = (byte)((timestamp >> 0) & 0xFF);
+										if (_isEncrypted)
+										{
+											Buffer.BlockCopy(rtpPacket, 2, nonce, 2, 6); //Update nonce
+											int ret = Sodium.Encrypt(packet, packet.Length, packet, nonce, _secretKey);
+											if (ret != 0)
+												continue;
+                                        }
 										Buffer.BlockCopy(packet, 0, rtpPacket, 12, packet.Length);
 #if USE_THREAD
 										_udp.Send(rtpPacket, packet.Length + 12);
@@ -298,8 +311,22 @@ namespace Discord.WebSockets.Voice
 							_heartbeatInterval = payload.HeartbeatInterval;
 							_ssrc = payload.SSRC;
 							_endpoint = new IPEndPoint((await Dns.GetHostAddressesAsync(Host.Replace("wss://", "")).ConfigureAwait(false)).FirstOrDefault(), payload.Port);
-							//_mode = payload.Modes.LastOrDefault();
+							
-							_isEncrypted = !payload.Modes.Contains("plain");
+							if (_client.Config.EnableVoiceEncryption)
+							{
+								if (payload.Modes.Contains(EncryptedMode))
+								{
+									_encryptionMode = EncryptedMode;
+									_isEncrypted = true;
+								}
+								else
+									throw new InvalidOperationException("Unexpected encryption format.");
+							}
+							else
+							{
+								_encryptionMode = UnencryptedMode;
+								_isEncrypted = false;
+                            }
                             _udp.Connect(_endpoint);
 
 							_sequence = (ushort)_rand.Next(0, ushort.MaxValue);
@@ -361,7 +388,7 @@ namespace Discord.WebSockets.Voice
 					var login2 = new Login2Command();
 					login2.Payload.Protocol = "udp";
 					login2.Payload.SocketData.Address = ip;
-					login2.Payload.SocketData.Mode = _isEncrypted ? EncryptedMode : UnencryptedMode;
+					login2.Payload.SocketData.Mode = _encryptionMode;
                     login2.Payload.SocketData.Port = port;
 					QueueMessage(login2);
 				}