private STUNMessage GetResponse(IPEndPoint receivedEndPoint, STUNMessage stunRequest, bool primary)
{
if (stunRequest.Header.MessageType == STUNMessageTypesEnum.BindingRequest)
{
STUNMessage stunResponse = new STUNMessage();
stunResponse.Header.MessageType = STUNMessageTypesEnum.BindingSuccessResponse;
stunResponse.Header.TransactionId = stunRequest.Header.TransactionId;
// Add MappedAddress attribute to indicate the socket the request was received from.
STUNAddressAttribute mappedAddressAtt = new STUNAddressAttribute(STUNAttributeTypesEnum.MappedAddress,
receivedEndPoint.Port, receivedEndPoint.Address);
stunResponse.Attributes.Add(mappedAddressAtt);
// Add SourceAddress attribute to indicate the socket used to send the response.
if (primary)
{
STUNAddressAttribute sourceAddressAtt = new STUNAddressAttribute(
STUNAttributeTypesEnum.SourceAddress, m_primaryEndPoint.Port, m_primaryEndPoint.Address);
stunResponse.Attributes.Add(sourceAddressAtt);
}
else
{
STUNAddressAttribute sourceAddressAtt = new STUNAddressAttribute(
STUNAttributeTypesEnum.SourceAddress, m_secondaryEndPoint.Port, m_secondaryEndPoint.Address);
stunResponse.Attributes.Add(sourceAddressAtt);
}
// Add ChangedAddress attribute to indicate the servers alternative socket.
if (primary)
{
STUNAddressAttribute changedAddressAtt = new STUNAddressAttribute(
STUNAttributeTypesEnum.ChangedAddress, m_secondaryEndPoint.Port, m_secondaryEndPoint.Address);
stunResponse.Attributes.Add(changedAddressAtt);
}
else
{
STUNAddressAttribute changedAddressAtt = new STUNAddressAttribute(
STUNAttributeTypesEnum.ChangedAddress, m_primaryEndPoint.Port, m_primaryEndPoint.Address);
stunResponse.Attributes.Add(changedAddressAtt);
}
//Console.WriteLine(stunResponse.ToString());
//byte[] stunResponseBuffer = stunResponse.ToByteBuffer();
return(stunResponse);
}
return(null);
}
public static List <STUNAttribute> ParseMessageAttributes(byte[] buffer, int startIndex, int endIndex)
{
if (buffer != null && buffer.Length > startIndex && buffer.Length >= endIndex)
{
List <STUNAttribute> attributes = new List <STUNAttribute>();
int startAttIndex = startIndex;
while (startAttIndex < endIndex)
{
UInt16 stunAttributeType = BitConverter.ToUInt16(buffer, startAttIndex);
UInt16 stunAttributeLength = BitConverter.ToUInt16(buffer, startAttIndex + 2);
byte[] stunAttributeValue = null;
if (BitConverter.IsLittleEndian)
{
stunAttributeType = NetConvert.DoReverseEndian(stunAttributeType);
stunAttributeLength = NetConvert.DoReverseEndian(stunAttributeLength);
}
if (stunAttributeLength > 0)
{
if (stunAttributeLength + startIndex + 4 > endIndex)
{
logger.LogWarning(
"The attribute length on a STUN parameter was greater than the available number of bytes.");
}
else
{
stunAttributeValue = new byte[stunAttributeLength];
Buffer.BlockCopy(buffer, startAttIndex + 4, stunAttributeValue, 0, stunAttributeLength);
}
}
STUNAttributeTypesEnum attributeType =
STUNAttributeTypes.GetSTUNAttributeTypeForId(stunAttributeType);
STUNAttribute attribute = null;
if (attributeType == STUNAttributeTypesEnum.ChangeRequest)
{
attribute = new STUNChangeRequestAttribute(stunAttributeValue);
}
else if (attributeType == STUNAttributeTypesEnum.MappedAddress)
{
attribute = new STUNAddressAttribute(stunAttributeValue);
}
else if (attributeType == STUNAttributeTypesEnum.ErrorCode)
{
attribute = new STUNErrorCodeAttribute(stunAttributeValue);
}
else if (attributeType == STUNAttributeTypesEnum.XORMappedAddress ||
attributeType == STUNAttributeTypesEnum.XORPeerAddress ||
attributeType == STUNAttributeTypesEnum.XORRelayedAddress)
{
attribute = new STUNXORAddressAttribute(attributeType, stunAttributeValue);
}
else
{
attribute = new STUNAttribute(attributeType, stunAttributeValue);
}
attributes.Add(attribute);
// Attributes start on 32 bit word boundaries so where an attribute length is not a multiple of 4 it gets padded.
int padding = (stunAttributeLength % 4 != 0) ? 4 - (stunAttributeLength % 4) : 0;
startAttIndex = startAttIndex + 4 + stunAttributeLength + padding;
}
return(attributes);
}
else
{
return(null);
}
}
public static List<STUNAttribute> ParseMessageAttributes(byte[] buffer, int startIndex, int endIndex)
{
if (buffer != null && buffer.Length > startIndex && buffer.Length >= endIndex)
{
List<STUNAttribute> attributes = new List<STUNAttribute>();
int startAttIndex = startIndex;
while (startAttIndex < endIndex)
{
UInt16 stunAttributeType = BitConverter.ToUInt16(buffer, startAttIndex);
UInt16 stunAttributeLength = BitConverter.ToUInt16(buffer, startAttIndex + 2);
byte[] stunAttributeValue = null;
if (BitConverter.IsLittleEndian)
{
stunAttributeType = Utility.ReverseEndian(stunAttributeType);
stunAttributeLength = Utility.ReverseEndian(stunAttributeLength);
}
if (stunAttributeLength > 0)
{
if (stunAttributeType == (int)STUNAttributeTypesEnum.Username && stunAttributeLength > buffer.Length - startIndex - 4)
{
// Received some STUN messages where the username is shorter than the claimed length.
int realLength = buffer.Length - startIndex - 4;
stunAttributeValue = new byte[realLength];
Buffer.BlockCopy(buffer, startIndex + 4, stunAttributeValue, 0, realLength);
}
else
{
stunAttributeValue = new byte[stunAttributeLength];
Buffer.BlockCopy(buffer, startIndex + 4, stunAttributeValue, 0, stunAttributeLength);
}
}
STUNAttributeTypesEnum attributeType = STUNAttributeTypes.GetSTUNAttributeTypeForId(stunAttributeType);
STUNAttribute attribute = null;
if (attributeType == STUNAttributeTypesEnum.ChangeRequest)
{
attribute = new STUNChangeRequestAttribute(stunAttributeValue);
}
else if (attributeType == STUNAttributeTypesEnum.MappedAddress)
{
attribute = new STUNAddressAttribute(stunAttributeValue);
}
else
{
attribute = new STUNAttribute(attributeType, stunAttributeLength, stunAttributeValue);
}
attributes.Add(attribute);
startAttIndex = startAttIndex + 4 + stunAttributeLength;
}
return attributes;
}
else
{
return null;
}
}
/// <summary>
/// Used to get the public IP address and port as seen by the STUN server.
/// </summary>
/// <param name="stunServer">A server to send STUN requests to.</param>
/// <param name="port">The port to use for the request. Defaults to 3478.</param>
/// <returns>The public IP address and port of the client.</returns>
public static IPEndPoint GetPublicIPEndPoint(string stunServer, int port = DEFAULT_STUN_PORT)
{
try
{
logger.LogDebug("STUNClient attempting to determine public IP from " + stunServer + ".");
using (UdpClient udpClient = new UdpClient(stunServer, port))
{
STUNMessage initMessage = new STUNMessage(STUNMessageTypesEnum.BindingRequest);
byte[] stunMessageBytes = initMessage.ToByteBuffer(null, false);
udpClient.Send(stunMessageBytes, stunMessageBytes.Length);
IPEndPoint publicEndPoint = null;
ManualResetEvent gotResponseMRE = new ManualResetEvent(initialState: false);
udpClient.BeginReceive((ar) =>
{
try
{
IPEndPoint stunResponseEndPoint = null;
byte[] stunResponseBuffer = udpClient.EndReceive(ar, ref stunResponseEndPoint);
if (stunResponseBuffer != null && stunResponseBuffer.Length > 0)
{
logger.LogDebug("STUNClient Response to initial STUN message received from " + stunResponseEndPoint + ".");
STUNMessage stunResponse = STUNMessage.ParseSTUNMessage(stunResponseBuffer, stunResponseBuffer.Length);
if (stunResponse.Attributes.Count > 0)
{
foreach (STUNAttribute stunAttribute in stunResponse.Attributes)
{
if (stunAttribute.AttributeType == STUNAttributeTypesEnum.MappedAddress)
{
STUNAddressAttribute stunAddress = (STUNAddressAttribute)stunAttribute;
publicEndPoint = new IPEndPoint(stunAddress.Address, stunAddress.Port);
logger.LogDebug($"STUNClient Public IP={publicEndPoint.Address} Port={publicEndPoint.Port}.");
}
}
}
}
gotResponseMRE.Set();
}
catch (Exception recvExcp)
{
logger.LogWarning("Exception STUNClient Receive. " + recvExcp.Message);
}
}, state: null);
if (gotResponseMRE.WaitOne(STUN_SERVER_RESPONSE_TIMEOUT * 1000))
{
return(publicEndPoint);
}
else
{
logger.LogWarning("STUNClient server response timed out after " + STUN_SERVER_RESPONSE_TIMEOUT + "s.");
return(null);
}
}
}
catch (Exception excp)
{
logger.LogError("Exception STUNClient GetPublicIPAddress. " + excp.Message);
return(null);
}
}
public static List <STUNAttribute> ParseMessageAttributes(byte[] buffer, int startIndex, int endIndex)
{
if (buffer != null && buffer.Length > startIndex && buffer.Length >= endIndex)
{
List <STUNAttribute> attributes = new List <STUNAttribute>();
int startAttIndex = startIndex;
while (startAttIndex < endIndex)
{
UInt16 stunAttributeType = BitConverter.ToUInt16(buffer, startAttIndex);
UInt16 stunAttributeLength = BitConverter.ToUInt16(buffer, startAttIndex + 2);
byte[] stunAttributeValue = null;
if (BitConverter.IsLittleEndian)
{
stunAttributeType = Utility.ReverseEndian(stunAttributeType);
stunAttributeLength = Utility.ReverseEndian(stunAttributeLength);
}
if (stunAttributeLength > 0)
{
if (stunAttributeType == (int)STUNAttributeTypesEnum.Username && stunAttributeLength > buffer.Length - startIndex - 4)
{
// Received some STUN messages where the username is shorter than the claimed length.
int realLength = buffer.Length - startIndex - 4;
stunAttributeValue = new byte[realLength];
Buffer.BlockCopy(buffer, startIndex + 4, stunAttributeValue, 0, realLength);
}
else
{
stunAttributeValue = new byte[stunAttributeLength];
Buffer.BlockCopy(buffer, startIndex + 4, stunAttributeValue, 0, stunAttributeLength);
}
}
STUNAttributeTypesEnum attributeType = STUNAttributeTypes.GetSTUNAttributeTypeForId(stunAttributeType);
STUNAttribute attribute = null;
if (attributeType == STUNAttributeTypesEnum.ChangeRequest)
{
attribute = new STUNChangeRequestAttribute(stunAttributeValue);
}
else if (attributeType == STUNAttributeTypesEnum.MappedAddress)
{
attribute = new STUNAddressAttribute(stunAttributeValue);
}
else
{
attribute = new STUNAttribute(attributeType, stunAttributeLength, stunAttributeValue);
}
attributes.Add(attribute);
startAttIndex = startAttIndex + 4 + stunAttributeLength;
}
return(attributes);
}
else
{
return(null);
}
}
private STUNMessage GetResponse(IPEndPoint receivedEndPoint, STUNMessage stunRequest, bool primary)
{
if (stunRequest.Header.MessageType == STUNMessageTypesEnum.BindingRequest)
{
STUNMessage stunResponse = new STUNMessage();
stunResponse.Header.MessageType = STUNMessageTypesEnum.BindingResponse;
stunResponse.Header.TransactionId = stunRequest.Header.TransactionId;
// Add MappedAddress attribute to indicate the socket the request was received from.
STUNAddressAttribute mappedAddressAtt = new STUNAddressAttribute(STUNAttributeTypesEnum.MappedAddress, receivedEndPoint.Port, receivedEndPoint.Address);
stunResponse.Attributes.Add(mappedAddressAtt);
// Add SourceAddress attribute to indicate the socket used to send the response.
if (primary)
{
STUNAddressAttribute sourceAddressAtt = new STUNAddressAttribute(STUNAttributeTypesEnum.SourceAddress, m_primaryEndPoint.Port, m_primaryEndPoint.Address);
stunResponse.Attributes.Add(sourceAddressAtt);
}
else
{
STUNAddressAttribute sourceAddressAtt = new STUNAddressAttribute(STUNAttributeTypesEnum.SourceAddress, m_secondaryEndPoint.Port, m_secondaryEndPoint.Address);
stunResponse.Attributes.Add(sourceAddressAtt);
}
// Add ChangedAddress attribute to inidcate the servers alternative socket.
if (primary)
{
STUNAddressAttribute changedAddressAtt = new STUNAddressAttribute(STUNAttributeTypesEnum.ChangedAddress, m_secondaryEndPoint.Port, m_secondaryEndPoint.Address);
stunResponse.Attributes.Add(changedAddressAtt);
}
else
{
STUNAddressAttribute changedAddressAtt = new STUNAddressAttribute(STUNAttributeTypesEnum.ChangedAddress, m_primaryEndPoint.Port, m_primaryEndPoint.Address);
stunResponse.Attributes.Add(changedAddressAtt);
}
//Console.WriteLine(stunResponse.ToString());
//byte[] stunResponseBuffer = stunResponse.ToByteBuffer();
return stunResponse;
}
return null;
}
