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);
}
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);
}
}