/// <summary>
/// From RFC5764:
/// +----------------+
/// | 127 < B< 192 -+--> forward to RTP
/// | |
/// packet --> | 19 < B< 64 -+--> forward to DTLS
/// | |
/// | B< 2 -+--> forward to STUN
/// +----------------+
/// </summary>
/// <paramref name="localPort">The local port on the RTP socket that received the packet.</paramref>
/// <param name="remoteEP">The remote end point the packet was received from.</param>
/// <param name="buffer">The data received.</param>
private void OnRTPDataReceived(int localPort, IPEndPoint remoteEP, byte[] buffer)
{
//logger.LogDebug($"RTP channel received a packet from {remoteEP}, {buffer?.Length} bytes.");
// By this pint the RTP ICE channel has already processed any STUN packets which means
// it's only necessary to separate RTP/RTCP from DTLS.
// Because DTLS packets can be fragmented and RTP/RTCP should never be use the RTP/RTCP
// prefix to distinguish.
if (buffer?.Length > 0)
{
try
{
if (buffer?.Length > RTPHeader.MIN_HEADER_LEN && buffer[0] >= 128 && buffer[0] <= 191)
{
// RTP/RTCP packet.
base.OnReceive(localPort, remoteEP, buffer);
}
else
//if (buffer[0] >= 20 && buffer[0] <= 63)
{
// DTLS packet.
OnDtlsPacket?.Invoke(buffer);
}
}
catch (Exception excp)
{
logger.LogError($"Exception RTCPeerConnection.OnRTPDataReceived {excp.Message}");
}
}
}
private void StartWebRtcRtpListener(IceCandidate iceCandidate)
{
string localEndPoint = "?";
try
{
localEndPoint = iceCandidate.LocalRtpSocket.LocalEndPoint.ToString();
logger.LogDebug("Starting WebRTC RTP listener for call " + CallID + " on socket " + localEndPoint + ".");
IPEndPoint remoteEndPoint = new IPEndPoint(IPAddress.Any, 0);
UdpClient localSocket = new UdpClient();
localSocket.Client = iceCandidate.LocalRtpSocket;
while (!IsClosed)
{
try
{
//logger.LogDebug("ListenToReceiverWebRTCClient Receive.");
byte[] buffer = localSocket.Receive(ref remoteEndPoint);
iceCandidate.LastCommunicationAt = DateTime.Now;
//logger.LogDebug(buffer.Length + " bytes read on Receiver Client media socket from " + remoteEndPoint.ToString() + ".");
//if (buffer.Length > 3 && buffer[0] == 0x16 && buffer[1] == 0xfe)
if (buffer[0] >= 20 && buffer[0] <= 64)
{
//OnMediaPacket(iceCandidate, buffer, remoteEndPoint);
OnDtlsPacket?.Invoke(iceCandidate, buffer, remoteEndPoint);
}
//else if ((buffer[0] & 0x80) == 0)
else if (buffer[0] == 0 || buffer[0] == 1)
{
STUNv2Message stunMessage = STUNv2Message.ParseSTUNMessage(buffer, buffer.Length);
ProcessStunMessage(iceCandidate, stunMessage, remoteEndPoint);
}
else
{
OnMediaPacket?.Invoke(iceCandidate, buffer, remoteEndPoint);
}
}
catch (Exception sockExcp)
{
_communicationFailureCount++;
logger.LogWarning("Exception ListenToReceiverWebRTCClient Receive (" + localEndPoint + " and " + remoteEndPoint + ", failure count " + _communicationFailureCount + "). " + sockExcp.Message);
// Need to be careful about deciding when the connection has failed. Sometimes the STUN requests we send will arrive before the remote peer is ready and cause a socket exception.
// Only shutdown the peer if we are sure all ICE intialisation is complete and the socket exception occurred after the RTP had stated flowing.
if (iceCandidate.IsStunLocalExchangeComplete && iceCandidate.IsStunRemoteExchangeComplete &&
iceCandidate.RemoteRtpEndPoint != null && remoteEndPoint != null && iceCandidate.RemoteRtpEndPoint.ToString() == remoteEndPoint.ToString() &&
DateTime.Now.Subtract(IceNegotiationStartedAt).TotalSeconds > 10)
{
logger.LogWarning("WebRtc peer communication failure on call " + CallID + " for local RTP socket " + localEndPoint + " and remote RTP socket " + remoteEndPoint + " .");
iceCandidate.DisconnectionMessage = sockExcp.Message;
break;
}
else if (_communicationFailureCount > COMMUNICATION_FAILURE_COUNT_FOR_CLOSE)
{
logger.LogWarning("WebRtc peer communication failures on call " + CallID + " exceeded limit of " + COMMUNICATION_FAILURE_COUNT_FOR_CLOSE + " closing peer.");
break;
}
//else if (DateTime.Now.Subtract(peer.IceNegotiationStartedAt).TotalSeconds > ICE_CONNECTION_LIMIT_SECONDS)
//{
// logger.LogWarning("WebRTC peer ICE connection establishment timed out on call " + peer.CallID + " for " + iceCandidate.LocalRtpSocket.LocalEndPoint + ".");
// break;
//}
}
}
Close();
}
catch (Exception excp)
{
logger.LogError("Exception ListenForWebRTCClient (" + localEndPoint + "). " + excp);
}
}
