public static STUNMessage ParseSTUNMessage(byte[] buffer, int bufferLength)
{
if (buffer != null && buffer.Length > 0 && buffer.Length >= bufferLength)
{
STUNMessage stunMessage = new STUNMessage();
stunMessage.Header = STUNHeader.ParseSTUNHeader(buffer);
if (stunMessage.Header.MessageLength > 0)
{
stunMessage.Attributes = STUNAttribute.ParseMessageAttributes(buffer, STUNHeader.STUN_HEADER_LENGTH, bufferLength);
}
return(stunMessage);
}
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);
}
}