/// <summary>
/// Sends the RTCP report to the remote call party.
/// </summary>
/// <param name="report">RTCP report to send.</param>
private void SendRtcpReport(RTCPCompoundPacket report)
{
var reportBytes = report.GetBytes();
var sendOnSocket = (m_isMultiplexed) ? RTPChannelSocketsEnum.RTP : RTPChannelSocketsEnum.Control;
if (SrtcpProtect == null)
{
m_rtpChannel.SendAsync(sendOnSocket, ControlDestinationEndPoint, reportBytes);
}
else
{
byte[] sendBuffer = new byte[reportBytes.Length + SRTP_AUTH_KEY_LENGTH];
Buffer.BlockCopy(reportBytes, 0, sendBuffer, 0, reportBytes.Length);
int rtperr = SrtcpProtect(sendBuffer, sendBuffer.Length - SRTP_AUTH_KEY_LENGTH);
if (rtperr != 0)
{
logger.LogWarning("SRTP RTCP packet protection failed, result " + rtperr + ".");
}
else
{
m_rtpChannel.SendAsync(sendOnSocket, ControlDestinationEndPoint, sendBuffer);
}
}
}
/// <summary>
/// Performs a connectivity check for a single candidate pair entry.
/// </summary>
/// <param name="candidatePair">The candidate pair to perform a connectivity check for.</param>
/// <param name="setUseCandidate">If true indicates we are acting as the "controlling" ICE agent
/// and are nominating this candidate as the chosen one.</param>
/// <remarks>As specified in https://tools.ietf.org/html/rfc8445#section-7.2.4.</remarks>
private void SendConnectivityCheck(ChecklistEntry candidatePair, bool setUseCandidate)
{
candidatePair.State = ChecklistEntryState.InProgress;
candidatePair.LastCheckSentAt = DateTime.Now;
candidatePair.ChecksSent++;
candidatePair.RequestTransactionID = Crypto.GetRandomString(STUNv2Header.TRANSACTION_ID_LENGTH);
IPEndPoint remoteEndPoint = candidatePair.RemoteCandidate.GetEndPoint();
logger.LogDebug($"Sending ICE connectivity check from {_rtpChannel.RTPLocalEndPoint} to {remoteEndPoint} (use candidate {setUseCandidate}).");
STUNv2Message stunRequest = new STUNv2Message(STUNv2MessageTypesEnum.BindingRequest);
stunRequest.Header.TransactionId = Encoding.ASCII.GetBytes(candidatePair.RequestTransactionID);
stunRequest.AddUsernameAttribute(RemoteIceUser + ":" + LocalIceUser);
stunRequest.Attributes.Add(new STUNv2Attribute(STUNv2AttributeTypesEnum.Priority, BitConverter.GetBytes(candidatePair.Priority)));
if (setUseCandidate)
{
stunRequest.Attributes.Add(new STUNv2Attribute(STUNv2AttributeTypesEnum.UseCandidate, null));
}
byte[] stunReqBytes = stunRequest.ToByteBufferStringKey(RemoteIcePassword, true);
_rtpChannel.SendAsync(RTPChannelSocketsEnum.RTP, remoteEndPoint, stunReqBytes);
}
/// <summary>
/// Does the actual sending of an RTP packet using the specified data nad header values.
/// </summary>
/// <param name="rtpChannel">The RTP channel to send from.</param>
/// <param name="dstRtpSocket">Destination to send to.</param>
/// <param name="data">The RTP packet payload.</param>
/// <param name="timestamp">The RTP header timestamp.</param>
/// <param name="markerBit">The RTP header marker bit.</param>
/// <param name="payloadType">The RTP header payload type.</param>
private void SendRtpPacket(RTPChannel rtpChannel, IPEndPoint dstRtpSocket, byte[] data, uint timestamp, int markerBit, int payloadType)
{
int srtpProtectionLength = (SrtpProtect != null) ? SRTP_AUTH_KEY_LENGTH : 0;
RTPPacket rtpPacket = new RTPPacket(data.Length + srtpProtectionLength);
rtpPacket.Header.SyncSource = Ssrc;
rtpPacket.Header.SequenceNumber = SeqNum;
rtpPacket.Header.Timestamp = timestamp;
rtpPacket.Header.MarkerBit = markerBit;
rtpPacket.Header.PayloadType = payloadType;
Buffer.BlockCopy(data, 0, rtpPacket.Payload, 0, data.Length);
OnRtpPacketSent?.Invoke(rtpPacket);
var rtpBuffer = rtpPacket.GetBytes();
int rtperr = SrtpProtect == null ? 0 : SrtpProtect(rtpBuffer, rtpBuffer.Length - srtpProtectionLength);
if (rtperr != 0)
{
logger.LogError("SendDtmfEvent SRTP packet protection failed, result " + rtperr + ".");
}
else
{
rtpChannel.SendAsync(RTPChannelSocketsEnum.RTP, dstRtpSocket, rtpBuffer);
}
}
/// <summary>
/// Does the actual sending of an RTP packet using the specified data and header values.
/// </summary>
/// <param name="rtpChannel">The RTP channel to send from.</param>
/// <param name="dstRtpSocket">Destination to send to.</param>
/// <param name="data">The RTP packet payload.</param>
/// <param name="timestamp">The RTP header timestamp.</param>
/// <param name="markerBit">The RTP header marker bit.</param>
/// <param name="payloadType">The RTP header payload type.</param>
private void SendRtpPacket(RTPChannel rtpChannel, IPEndPoint dstRtpSocket, byte[] data, uint timestamp, int markerBit, int payloadType, uint ssrc, ushort seqNum, RTCPSession rtcpSession)
{
if (IsSecure && !IsSecureContextReady)
{
logger.LogWarning("SendRtpPacket cannot be called on a secure session before calling SetSecurityContext.");
}
else
{
int srtpProtectionLength = (m_srtpProtect != null) ? SRTP_MAX_PREFIX_LENGTH : 0;
RTPPacket rtpPacket = new RTPPacket(data.Length + srtpProtectionLength);
rtpPacket.Header.SyncSource = ssrc;
rtpPacket.Header.SequenceNumber = seqNum;
rtpPacket.Header.Timestamp = timestamp;
rtpPacket.Header.MarkerBit = markerBit;
rtpPacket.Header.PayloadType = payloadType;
Buffer.BlockCopy(data, 0, rtpPacket.Payload, 0, data.Length);
var rtpBuffer = rtpPacket.GetBytes();
if (m_srtpProtect == null)
{
rtpChannel.SendAsync(RTPChannelSocketsEnum.RTP, dstRtpSocket, rtpBuffer);
}
else
{
int outBufLen = 0;
int rtperr = m_srtpProtect(rtpBuffer, rtpBuffer.Length - srtpProtectionLength, out outBufLen);
if (rtperr != 0)
{
logger.LogError("SendRTPPacket protection failed, result " + rtperr + ".");
}
else
{
rtpChannel.SendAsync(RTPChannelSocketsEnum.RTP, dstRtpSocket, rtpBuffer.Take(outBufLen).ToArray());
}
}
m_lastRtpTimestamp = timestamp;
rtcpSession?.RecordRtpPacketSend(rtpPacket);
}
}
private async Task SendTurnServerBindingRequest(IceCandidate iceCandidate)
{
int attempt = 1;
while (attempt < INITIAL_STUN_BINDING_ATTEMPTS_LIMIT && !IsConnected && !IsClosed && !iceCandidate.IsGatheringComplete)
{
logger.LogDebug($"Sending STUN binding request {attempt} from {_rtpChannel.RTPLocalEndPoint} to {iceCandidate.TurnServer.ServerEndPoint}.");
STUNv2Message stunRequest = new STUNv2Message(STUNv2MessageTypesEnum.BindingRequest);
stunRequest.Header.TransactionId = Guid.NewGuid().ToByteArray().Take(12).ToArray();
byte[] stunReqBytes = stunRequest.ToByteBuffer(null, false);
_rtpChannel.SendAsync(RTPChannelSocketsEnum.RTP, iceCandidate.TurnServer.ServerEndPoint, stunReqBytes);
await Task.Delay(INITIAL_STUN_BINDING_PERIOD_MILLISECONDS);
attempt++;
}
iceCandidate.IsGatheringComplete = true;
}
/// <summary>
/// Attempts to get a list of local ICE candidates.
/// </summary>
//private async Task GetIceCandidatesAsync()
//{
// // The media is being multiplexed so the audio and video RTP channel is the same.
// var rtpChannel = GetRtpChannel(SDPMediaTypesEnum.audio);
// if (rtpChannel == null)
// {
// throw new ApplicationException("Cannot start gathering ICE candidates without an RTP channel.");
// }
// else
// {
// var localIPAddresses = _offerAddresses ?? NetServices.GetAllLocalIPAddresses();
// IceNegotiationStartedAt = DateTime.Now;
// LocalIceCandidates = new List<IceCandidate>();
// foreach (var address in localIPAddresses.Where(x => x.AddressFamily == rtpChannel.RTPLocalEndPoint.AddressFamily))
// {
// var iceCandidate = new IceCandidate(address, (ushort)rtpChannel.RTPPort);
// if (_turnServerEndPoint != null)
// {
// iceCandidate.TurnServer = new TurnServer() { ServerEndPoint = _turnServerEndPoint };
// iceCandidate.InitialStunBindingCheck = SendTurnServerBindingRequest(iceCandidate);
// }
// LocalIceCandidates.Add(iceCandidate);
// }
// await Task.WhenAll(LocalIceCandidates.Where(x => x.InitialStunBindingCheck != null).Select(x => x.InitialStunBindingCheck)).ConfigureAwait(false);
// }
//}
public void ProcessStunMessage(STUNv2Message stunMessage, IPEndPoint receivedOn)
{
IPEndPoint remoteEndPoint = (!receivedOn.Address.IsIPv4MappedToIPv6) ? receivedOn : new IPEndPoint(receivedOn.Address.MapToIPv4(), receivedOn.Port);
//logger.LogDebug($"STUN message received from remote {remoteEndPoint} {stunMessage.Header.MessageType}.");
if (stunMessage.Header.MessageType == STUNv2MessageTypesEnum.BindingRequest)
{
STUNv2Message stunResponse = new STUNv2Message(STUNv2MessageTypesEnum.BindingSuccessResponse);
stunResponse.Header.TransactionId = stunMessage.Header.TransactionId;
stunResponse.AddXORMappedAddressAttribute(remoteEndPoint.Address, remoteEndPoint.Port);
// ToDo: Check authentication.
string localIcePassword = LocalIcePassword;
byte[] stunRespBytes = stunResponse.ToByteBufferStringKey(localIcePassword, true);
//iceCandidate.LocalRtpSocket.SendTo(stunRespBytes, remoteEndPoint);
_rtpChannel.SendAsync(RTPChannelSocketsEnum.RTP, remoteEndPoint, stunRespBytes);
//iceCandidate.LastStunRequestReceivedAt = DateTime.Now;
//iceCandidate.IsStunRemoteExchangeComplete = true;
//if (remoteEndPoint == null)
//{
//RemoteEndPoint = remoteEndPoint;
//SetDestination(SDPMediaTypesEnum.audio, RemoteEndPoint, RemoteEndPoint);
//OnIceConnected?.Invoke(iceCandidate, remoteEndPoint);
//IceConnectionState = RTCIceConnectionState.connected;
//}
if (_remoteCandidates != null && !_remoteCandidates.Any(x =>
(x.address == remoteEndPoint.Address.ToString() || x.relatedAddress == remoteEndPoint.Address.ToString()) &&
(x.port == remoteEndPoint.Port || x.relatedPort == remoteEndPoint.Port)))
{
// This STUN request has come from a socket not in the remote ICE candidates list. Add it so we can send our STUN binding request to it.
// RTCIceCandidate remoteIceCandidate = new IceCandidate("udp", remoteEndPoint.Address, (ushort)remoteEndPoint.Port, RTCIceCandidateType.host);
RTCIceCandidate peerRflxCandidate = new RTCIceCandidate(new RTCIceCandidateInit());
peerRflxCandidate.SetAddressProperties(RTCIceProtocol.udp, remoteEndPoint.Address, (ushort)remoteEndPoint.Port, RTCIceCandidateType.prflx, null, 0);
logger.LogDebug($"Adding peer reflex ICE candidate for {remoteEndPoint}.");
_remoteCandidates.Add(peerRflxCandidate);
// Some browsers require a STUN binding request from our end before the DTLS handshake will be initiated.
// The STUN connectivity checks are already scheduled but we can speed things up by sending a binding
// request immediately.
SendStunConnectivityChecks(null);
}
}
else if (stunMessage.Header.MessageType == STUNv2MessageTypesEnum.BindingSuccessResponse)
{
if (ConnectionState != RTCIceConnectionState.connected)
{
logger.LogDebug($"ICE session setting connected remote end point to {remoteEndPoint}.");
_connectedRemoteEndPoint = remoteEndPoint;
ConnectionState = RTCIceConnectionState.connected;
OnIceConnectionStateChange?.Invoke(RTCIceConnectionState.connected);
}
// TODO: What needs to be done here?
//if (_turnServerEndPoint != null && remoteEndPoint.ToString() == _turnServerEndPoint.ToString())
//{
// if (iceCandidate.IsGatheringComplete == false)
// {
// var reflexAddressAttribute = stunMessage.Attributes.FirstOrDefault(y => y.AttributeType == STUNv2AttributeTypesEnum.XORMappedAddress) as STUNv2XORAddressAttribute;
// if (reflexAddressAttribute != null)
// {
// iceCandidate.StunRflxIPEndPoint = new IPEndPoint(reflexAddressAttribute.Address, reflexAddressAttribute.Port);
// iceCandidate.IsGatheringComplete = true;
// logger.LogDebug("ICE gathering complete for local socket " + iceCandidate.RtpChannel.RTPLocalEndPoint + ", rflx address " + iceCandidate.StunRflxIPEndPoint + ".");
// }
// else
// {
// iceCandidate.IsGatheringComplete = true;
// logger.LogDebug("The STUN binding response received on " + iceCandidate.RtpChannel.RTPLocalEndPoint + " from " + remoteEndPoint + " did not have an XORMappedAddress attribute, rlfx address can not be determined.");
// }
// }
//}
//else
//{
// iceCandidate.LastStunResponseReceivedAt = DateTime.Now;
// if (iceCandidate.IsStunLocalExchangeComplete == false)
// {
// iceCandidate.IsStunLocalExchangeComplete = true;
// logger.LogDebug("WebRTC client STUN exchange complete for call " + CallID + ", candidate local socket " + iceCandidate.RtpChannel.RTPLocalEndPoint + ", remote socket " + remoteEndPoint + ".");
// SetIceConnectionState(IceConnectionStatesEnum.Connected);
// }
//}
}
else if (stunMessage.Header.MessageType == STUNv2MessageTypesEnum.BindingErrorResponse)
{
logger.LogWarning($"A STUN binding error response was received from {remoteEndPoint}.");
}
else
{
logger.LogWarning($"An unrecognised STUN request was received from {remoteEndPoint}.");
}
}
