public void TestMessageIntegrityAttributeForBindingRequest()
{
Console.WriteLine(System.Reflection.MethodBase.GetCurrentMethod().Name);
byte[] stunReq = new byte[] {
0x00, 0x01, 0x00, 0x60, 0x21, 0x12, 0xa4, 0x42, 0x69, 0x64, 0x38, 0x2b, 0x4c, 0x45, 0x44, 0x57,
0x4d, 0x31, 0x64, 0x30, 0x00, 0x06, 0x00, 0x21, 0x75, 0x4f, 0x35, 0x73, 0x69, 0x31, 0x75, 0x61,
0x37, 0x63, 0x59, 0x34, 0x74, 0x38, 0x4d, 0x4d, 0x3a, 0x4c, 0x77, 0x38, 0x2f, 0x30, 0x43, 0x31,
0x43, 0x72, 0x76, 0x68, 0x5a, 0x43, 0x31, 0x67, 0x62, 0x00, 0x00, 0x00, 0x80, 0x2a, 0x00, 0x08,
0xc0, 0x3d, 0xf5, 0x13, 0x40, 0xf4, 0x22, 0x46, 0x00, 0x25, 0x00, 0x00, 0x00, 0x24, 0x00, 0x04,
0x6e, 0x7f, 0x1e, 0xff, 0x00, 0x08, 0x00, 0x14, 0x55, 0x82, 0x69, 0xde, 0x17, 0x55, 0xcc, 0x66,
0x29, 0x23, 0xe6, 0x7d, 0xec, 0x87, 0x6c, 0x07, 0x3a, 0xd6, 0x78, 0x15, 0x80, 0x28, 0x00, 0x04,
0x1c, 0xae, 0x89, 0x2e
};
STUNv2Message stunMessage = STUNv2Message.ParseSTUNMessage(stunReq, stunReq.Length);
STUNv2Header stunHeader = stunMessage.Header;
Console.WriteLine("Request type = " + stunHeader.MessageType + ".");
Console.WriteLine("Length = " + stunHeader.MessageLength + ".");
Console.WriteLine("Transaction ID = " + BitConverter.ToString(stunHeader.TransactionId) + ".");
Assert.AreEqual(STUNv2MessageTypesEnum.BindingRequest, stunHeader.MessageType);
Assert.AreEqual(96, stunHeader.MessageLength);
Assert.AreEqual(6, stunMessage.Attributes.Count);
Assert.AreEqual("69-64-38-2B-4C-45-44-57-4D-31-64-30", BitConverter.ToString(stunMessage.Header.TransactionId));
stunMessage.Attributes.Remove(stunMessage.Attributes.Where(x => x.AttributeType == STUNv2AttributeTypesEnum.MessageIntegrity).Single());
stunMessage.Attributes.Remove(stunMessage.Attributes.Where(x => x.AttributeType == STUNv2AttributeTypesEnum.FingerPrint).Single());
byte[] buffer = stunMessage.ToByteBufferStringKey("r89XhWC9k2kW4Pns75vmwHIa", true);
Assert.AreEqual(BitConverter.ToString(stunReq), BitConverter.ToString(buffer));
}
public void GenerateHmacAndFingerprintTestMethod()
{
logger.LogDebug("--> " + System.Reflection.MethodBase.GetCurrentMethod().Name);
logger.BeginScope(System.Reflection.MethodBase.GetCurrentMethod().Name);
string icePassword = "******";
STUNv2Message msg = new STUNv2Message(STUNv2MessageTypesEnum.BindingSuccessResponse);
msg.Header.TransactionId = new byte[] { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
msg.AddXORMappedAddressAttribute(IPAddress.Loopback, 55477);
var buffer = msg.ToByteBufferStringKey(icePassword, true);
string hmac = "HMAC: ";
for (int i = 36; i < 56; i++)
{
hmac += $"{buffer[i]:X2} ";
}
logger.LogDebug(hmac);
logger.LogDebug($"Fingerprint: {buffer[buffer.Length - 4]:X2} {buffer[buffer.Length - 3]:X2} {buffer[buffer.Length - 2]:X2} {buffer[buffer.Length - 1]:X2}.");
}
private void ProcessStunMessage(IceCandidate iceCandidate, STUNv2Message stunMessage, IPEndPoint remoteEndPoint)
{
//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);
iceCandidate.LastStunRequestReceivedAt = DateTime.Now;
iceCandidate.IsStunRemoteExchangeComplete = true;
if (_isEncryptionDisabled == true)
{
iceCandidate.RemoteRtpEndPoint = remoteEndPoint; // Don't need to wait for DTLS negotiation.
OnIceConnected?.Invoke(iceCandidate, remoteEndPoint);
}
if (_remoteIceCandidates != null && !_remoteIceCandidates.Any(x =>
(x.NetworkAddress == remoteEndPoint.Address.ToString() || x.RemoteAddress == remoteEndPoint.Address.ToString()) &&
(x.Port == remoteEndPoint.Port || x.RemotePort == 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.
IceCandidate remoteIceCandidate = new IceCandidate()
{
Transport = "udp",
NetworkAddress = remoteEndPoint.Address.ToString(),
Port = remoteEndPoint.Port,
CandidateType = IceCandidateTypesEnum.host,
MediaType = iceCandidate.MediaType
};
logger.LogDebug("Adding missing remote ICE candidate for " + remoteEndPoint + " and media type " + iceCandidate.MediaType + ".");
_remoteIceCandidates.Add(remoteIceCandidate);
}
}
else if (stunMessage.Header.MessageType == STUNv2MessageTypesEnum.BindingSuccessResponse)
{
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.LocalRtpSocket.LocalEndPoint + ", rflx address " + iceCandidate.StunRflxIPEndPoint + ".");
}
else
{
iceCandidate.IsGatheringComplete = true;
logger.LogDebug("The STUN binding response received on " + iceCandidate.LocalRtpSocket.LocalEndPoint + " 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.LocalRtpSocket.LocalEndPoint + ", remote socket " + remoteEndPoint + ".");
SetIceConnectionState(IceConnectionStatesEnum.Connected);
}
}
}
else if (stunMessage.Header.MessageType == STUNv2MessageTypesEnum.BindingErrorResponse)
{
logger.LogWarning("A STUN binding error response was received on " + iceCandidate.LocalRtpSocket.LocalEndPoint + " from " + remoteEndPoint + ".");
}
else
{
logger.LogWarning("An unrecognised STUN request was received on " + iceCandidate.LocalRtpSocket.LocalEndPoint + " from " + remoteEndPoint + ".");
}
}
private void SendStunConnectivityChecks()
{
try
{
while (!IsClosed)
{
try
{
// If one of the ICE candidates has the remote RTP socket set then the negotiation is complete and the STUN checks are to keep the connection alive.
if (LocalIceCandidates.Any(x => x.IsConnected == true))
{
var iceCandidate = LocalIceCandidates.First(x => x.IsConnected == true);
// Remote RTP endpoint gets set when the DTLS negotiation is finished.
if (iceCandidate.RemoteRtpEndPoint != null)
{
//logger.LogDebug("Sending STUN connectivity check to client " + iceCandidate.RemoteRtpEndPoint + ".");
string localUser = LocalIceUser;
STUNv2Message stunRequest = new STUNv2Message(STUNv2MessageTypesEnum.BindingRequest);
stunRequest.Header.TransactionId = Guid.NewGuid().ToByteArray().Take(12).ToArray();
stunRequest.AddUsernameAttribute(RemoteIceUser + ":" + localUser);
stunRequest.Attributes.Add(new STUNv2Attribute(STUNv2AttributeTypesEnum.Priority, new byte[] { 0x6e, 0x7f, 0x1e, 0xff }));
stunRequest.Attributes.Add(new STUNv2Attribute(STUNv2AttributeTypesEnum.UseCandidate, null)); // Must send this to get DTLS started.
byte[] stunReqBytes = stunRequest.ToByteBufferStringKey(RemoteIcePassword, true);
iceCandidate.LocalRtpSocket.SendTo(stunReqBytes, iceCandidate.RemoteRtpEndPoint);
iceCandidate.LastSTUNSendAt = DateTime.Now;
}
var secondsSinceLastResponse = DateTime.Now.Subtract(iceCandidate.LastCommunicationAt).TotalSeconds;
if (secondsSinceLastResponse > ICE_TIMEOUT_SECONDS)
{
logger.LogWarning("No STUN response was received on a connected ICE connection for " + secondsSinceLastResponse + "s, closing connection.");
iceCandidate.IsDisconnected = true;
if (LocalIceCandidates.Any(x => x.IsConnected == true) == false)
{
// If there are no connected local candidates left close the peer.
Close();
break;
}
}
}
else
{
if (_remoteIceCandidates.Count() > 0)
{
foreach (var localIceCandidate in LocalIceCandidates.Where(x => x.IsStunLocalExchangeComplete == false && x.StunConnectionRequestAttempts < MAXIMUM_STUN_CONNECTION_ATTEMPTS))
{
localIceCandidate.StunConnectionRequestAttempts++;
// ToDo: Include srflx and relay addresses.
// Only supporting UDP candidates at this stage.
foreach (var remoteIceCandidate in RemoteIceCandidates.Where(x => x.Transport.ToLower() == "udp" && x.NetworkAddress.NotNullOrBlank() && x.HasConnectionError == false))
{
try
{
IPAddress remoteAddress = IPAddress.Parse(remoteIceCandidate.NetworkAddress);
logger.LogDebug("Sending authenticated STUN binding request " + localIceCandidate.StunConnectionRequestAttempts + " from " + localIceCandidate.LocalRtpSocket.LocalEndPoint + " to WebRTC peer at " + remoteIceCandidate.NetworkAddress + ":" + remoteIceCandidate.Port + ".");
string localUser = LocalIceUser;
STUNv2Message stunRequest = new STUNv2Message(STUNv2MessageTypesEnum.BindingRequest);
stunRequest.Header.TransactionId = Guid.NewGuid().ToByteArray().Take(12).ToArray();
stunRequest.AddUsernameAttribute(RemoteIceUser + ":" + localUser);
stunRequest.Attributes.Add(new STUNv2Attribute(STUNv2AttributeTypesEnum.Priority, new byte[] { 0x6e, 0x7f, 0x1e, 0xff }));
stunRequest.Attributes.Add(new STUNv2Attribute(STUNv2AttributeTypesEnum.UseCandidate, null)); // Must send this to get DTLS started.
byte[] stunReqBytes = stunRequest.ToByteBufferStringKey(RemoteIcePassword, true);
localIceCandidate.LocalRtpSocket.SendTo(stunReqBytes, new IPEndPoint(IPAddress.Parse(remoteIceCandidate.NetworkAddress), remoteIceCandidate.Port));
localIceCandidate.LastSTUNSendAt = DateTime.Now;
}
catch (System.Net.Sockets.SocketException sockExcp)
{
logger.LogWarning($"SocketException sending STUN request to {remoteIceCandidate.NetworkAddress}:{remoteIceCandidate.Port}, removing candidate. {sockExcp.Message}");
remoteIceCandidate.HasConnectionError = true;
}
}
}
}
}
}
catch (Exception excp)
{
logger.LogError("Exception SendStunConnectivityCheck ConnectivityCheck. " + excp);
}
if (!IsClosed)
{
Thread.Sleep(ESTABLISHED_STUN_BINDING_PERIOD_MILLISECONDS);
}
}
}
catch (Exception excp)
{
logger.LogError("Exception SendStunConnectivityCheck. " + excp);
}
}