//------------------------------------ SOURCE ADDRESS --------------------------
/**
* Creates a SourceFromAddressAttribute of the specified type and with
* the specified address and port
* @param address the address value of the address attribute
* @return the newly created address attribute.
*/
public static SourceAddressAttribute CreateSourceAddressAttribute(
StunAddress address)
{
SourceAddressAttribute attribute = new SourceAddressAttribute();
attribute.SetAddress(address);
return attribute;
}
/**
* Decodes the specified binary array and returns the corresponding
* attribute object.
* @param bytes the binary array that should be decoded.
* @param offset the index where the message starts.
* @param length the number of bytes that the message is long.
* @return An object representing the attribute encoded in bytes or null if
* the attribute was not recognized.
* @throws StunException if bytes does is not a valid STUN attribute.
*/
public static Attribute decode(byte[] bytes, int offset, int length)
{
if(bytes == null || bytes.Length < Attribute.HEADER_LENGTH)
throw new StunException(StunException.ILLEGAL_ARGUMENT,
"Could not decode the specified binary array.");
//Discover attribute type
int attributeTypec = (int)(((bytes[offset]<<8)&0xff00)|(bytes[offset + 1] & 0xff));
int attributeType = (int) attributeTypec;
int attributeLengthc = (int)(((bytes[offset + 2]<<8)&0xff00)|(bytes[offset + 3]&0xff));
int attributeLength = (int) attributeLengthc;
if(attributeLength > bytes.Length - offset )
{
throw new StunException(StunException.ILLEGAL_ARGUMENT,
"The indicated attribute length ("+attributeLength+") "
+"does not match the length of the passed binary array");
}
Attribute decodedAttribute = null;
switch(attributeType)
{
case Attribute.CHANGE_REQUEST:
decodedAttribute = new ChangeRequestAttribute(); break;
case Attribute.CHANGED_ADDRESS:
decodedAttribute = new ChangedAddressAttribute(); break;
case Attribute.MAPPED_ADDRESS:
decodedAttribute = new MappedAddressAttribute(); break;
case Attribute.ERROR_CODE:
decodedAttribute = new ErrorCodeAttribute(); break;
case Attribute.MESSAGE_INTEGRITY:
throw new StunException(
"The MESSAGE-INTEGRITY Attribute is not yet implemented.");
case Attribute.PASSWORD:
throw new StunException(
"The PASSWORD Attribute is not yet implemented.");
case Attribute.REFLECTED_FROM:
decodedAttribute = new ReflectedFromAttribute(); break;
case Attribute.RESPONSE_ADDRESS:
decodedAttribute = new ResponseAddressAttribute(); break;
case Attribute.SOURCE_ADDRESS:
decodedAttribute = new SourceAddressAttribute(); break;
case Attribute.UNKNOWN_ATTRIBUTES:
decodedAttribute = new UnknownAttributesAttribute(); break;
case Attribute.USERNAME:
throw new StunException(
"The USERNAME Attribute is not yet implemented.");
//According to rfc3489 we should silently ignore unknown attributes.
default:
decodedAttribute = new UnknownAttributesAttribute(); break;
//return null;
}
decodedAttribute.SetAttributeType(attributeType);
decodedAttribute.DecodeAttributeBody(bytes, (Attribute.HEADER_LENGTH + offset), attributeLength);
return decodedAttribute;
}
