async Task ReceiveLoop()
{
ArraySegment <byte> buffer = new ArraySegment <byte>(new byte[socket.ReceiveBufferSize]);
while (socket.Connected)
{
try
{
int read = await socket.ReceiveAsync(buffer, SocketFlags.None)
.ConfigureAwait(false);
if (read == 70 && discoveringIP)
{
HandleIPDiscoveryPacket(buffer.Array);
// For now, the receive loop is only needed for discovering the IP.
// To save from some unneeded calculations, we can end the loop here.
// TODO: remove when voice data receiving support is added.
break;
}
}
catch (ObjectDisposedException)
{
// Socket was disposed while receiving
break;
}
catch (SocketException ex)
{
if (ex.SocketErrorCode == SocketError.TimedOut)
{
// Since we have the receive timeout set to a finite value,
// if the bot is deafened, or has no one in the voice channel with it,
// it will time out on receiving, but this is okay.
continue;
}
else if (ex.SocketErrorCode == SocketError.Interrupted || ex.SocketErrorCode == SocketError.Shutdown)
{
// Socket was shutdown, just end loop.
break;
}
else
{
// Unexpected error
log.LogError($"[ReceiveLoop] Unexpected socket error: code = {ex.SocketErrorCode}, error = {ex}");
OnClosedPrematurely?.Invoke(this, EventArgs.Empty);
break;
}
}
catch (Exception ex)
{
// Unexpected error
log.LogError($"[ReceiveLoop] Unexpected error: {ex}");
OnClosedPrematurely?.Invoke(this, EventArgs.Empty);
break;
}
}
}
void SendLoop()
{
const int TICKS_PER_MS = 1;
const int MAX_OPUS_SIZE = 4000;
byte[] frame = new byte[encoder.FrameSize];
byte[] encodedFrame = new byte[MAX_OPUS_SIZE];
ushort sequence = 0;
uint timestamp = 0;
int ticksPerFrame = TICKS_PER_MS * encoder.FrameLength;
uint samplesPerFrame = (uint)encoder.SamplesPerFrame;
byte[] nonce = new byte[24];
byte[] voicePacket = new byte[MAX_OPUS_SIZE + 12 + 16];
int rtpPacketLength = 0;
// Setup RTP packet header
voicePacket[0] = 0x80; // Packet Type
voicePacket[1] = 0x78; // Packet Version
voicePacket[8] = (byte)(Ssrc >> 24); // ssrc
voicePacket[9] = (byte)(Ssrc >> 16);
voicePacket[10] = (byte)(Ssrc >> 8);
voicePacket[11] = (byte)(Ssrc >> 0);
// Copy RTP packet header into nonce
Buffer.BlockCopy(voicePacket, 0, nonce, 0, 12);
int nextTicks = Environment.TickCount;
// Begin send loop
bool hasFrame = false;
while (socket.Connected)
{
try
{
// If we don't have a frame to send and we have a frame buffered
if (!hasFrame && sendBuffer.Count > 0)
{
// Read frame from buffer
sendBuffer.Read(frame, 0, frame.Length);
// Set sequence number in RTP packet
voicePacket[2] = (byte)(sequence >> 8);
voicePacket[3] = (byte)(sequence >> 0);
// Set timestamp in RTP packet
voicePacket[4] = (byte)(timestamp >> 24);
voicePacket[5] = (byte)(timestamp >> 16);
voicePacket[6] = (byte)(timestamp >> 8);
voicePacket[7] = (byte)(timestamp >> 0);
// Increase the sequence number, use unchecked because wrapping is valid
unchecked { sequence++; };
// Encode the frame
int encodedLength = encoder.EncodeFrame(frame, 0, encodedFrame);
// Update the separately stored nonce from RTP packet
Buffer.BlockCopy(voicePacket, 2, nonce, 2, 6);
// Encrypt the frame
int encryptStatus = LibSodium.Encrypt(encodedFrame, encodedLength, voicePacket, 12, nonce, secretKey);
if (encryptStatus == 0)
{
// Update timestamp
timestamp = unchecked (timestamp + samplesPerFrame);
rtpPacketLength = encodedLength + 12 + 16;
hasFrame = true;
}
else
{
// Failed to encrypt
log.LogError($"[SendLoop] Failed to encrypt RTP packet. encryptStatus = {encryptStatus}");
}
}
int currentTicks = Environment.TickCount;
int ticksToNextFrame = nextTicks - currentTicks;
// Is it time to send the next frame?
if (ticksToNextFrame <= 0)
{
if (IsPaused)
{
// If we are paused, do nothing
Thread.Sleep(100);
}
// If we have a frame to send
else if (hasFrame)
{
hasFrame = false;
try
{
// Send the frame across UDP
Send(voicePacket, 0, rtpPacketLength);
}
catch (ObjectDisposedException)
{
// Socket was disposed while sending
break;
}
catch (SocketException ex)
{
if (ex.SocketErrorCode == SocketError.Interrupted || ex.SocketErrorCode == SocketError.Shutdown)
{
// Socket was shutdown while sending
break;
}
else
{
// Unexpected error
log.LogError($"[SendLoop] Unexpected socket error: code = {ex.SocketErrorCode}, error = {ex}");
OnClosedPrematurely?.Invoke(this, EventArgs.Empty);
break;
}
}
}
// Calculate the time for next frame
nextTicks += ticksPerFrame;
}
else
{
// Nothing to do, so sleep
Thread.Sleep(1);
}
}
catch (Exception ex)
{
// Unexpected error
log.LogError($"[SendLoop] Unexpected error: {ex}");
OnClosedPrematurely?.Invoke(this, EventArgs.Empty);
break;
}
}
}
