/**
* Creates a client transaction
* @param providerCallback the provider that created us.
* @param request the request that we are living for.
* @param requestDestination the destination of the request.
* @param apDescriptor the access point through which we are supposed to
* @param responseCollector the instance that should receive this request's
* response.
* retransmit.
*/
public StunClientTransaction(StunProvider providerCallback,
Request request,
StunAddress requestDestination,
NetAccessPointDescriptor apDescriptor,
ResponseCollector responseCollector)
{
this.providerCallback = providerCallback;
this.request = request;
this.apDescriptor = apDescriptor;
this.responseCollector = responseCollector;
this.requestDestination = requestDestination;
this.transactionID = TransactionID.CreateTransactionID();
request.SetTransactionID(transactionID.GetTransactionID());
runningThread = new Thread(new ThreadStart(this.Run));
}
/**
* Creates a default binding request. The request contains a ChangeReqeust
* attribute with zero change ip and change port flags.
* @return a default binding request.
*/
public static Request CreateBindingRequest()
{
Request bindingRequest = new Request();
try
{
bindingRequest.SetMessageType(Message.BINDING_REQUEST);
}
catch (StunException ex)
{
//there should be no exc here since we're the creators.
Console.WriteLine("Exception {0} {1}", ex.Message, ex.StackTrace);
}
//add a change request attribute
ChangeRequestAttribute attribute
= AttributeFactory.CreateChangeRequestAttribute();
bindingRequest.AddAttribute(attribute);
return bindingRequest;
}
/**
* Sends the specified request through the specified access point, and
* registers the specified ResponseCollector for later notification.
* @param request the request to send
* @param sendTo the destination address of the request.
* @param sendThrough the access point to use when sending the request
* @param collector the instance to notify when a response arrives or the
* the transaction timeouts
* @throws StunException
* ILLEGAL_STATE if the stun stack is not started. <br/>
* ILLEGAL_ARGUMENT if the apDescriptor references an access point that had
* not been installed <br/>
* NETWORK_ERROR if an error occurs while sending message bytes through the
* network socket. <br/>
*/
public virtual void SendRequest( Request request,
StunAddress sendTo,
NetAccessPointDescriptor sendThrough,
ResponseCollector collector )
{
stunStack.CheckStarted();
StunClientTransaction clientTransaction =
new StunClientTransaction(this,
request,
sendTo,
sendThrough,
collector);
clientTransactions[clientTransaction.GetTransactionID()] =
clientTransaction;
clientTransaction.SendRequest();
}
/**
* Sends the specified request and blocks until a response has been
* received or the request transaction has timed out.
* @param request the reuqest to send
* @param serverAddress the request destination address
* @return the event encapsulating the response or null if no response
* has been received.
* @throws StunException NETWORK_ERROR or other if we fail to send
* the message
*/
public virtual StunMessageEvent SendRequestAndWaitForResponse(
Request request,
StunAddress serverAddress)
{
Monitor.Enter(this);
try
{
stunProvider.SendRequest(request, serverAddress, apDescriptor,
this);
Monitor.Wait(this);
StunMessageEvent res = responseEvent;
responseEvent = null; //prepare for next message
return res;
}
finally
{
Monitor.Exit(this);
}
}
/**
* Constructs a message from its binary representation.
* @param binMessage the binary array that contains the encoded message
* @param offset the index where the message starts.
* @param arrayLen the length of the message
* @return a Message object constructed from the binMessage array
* @throws StunException ILLEGAL_ARGUMENT if one or more of the arguments
* have invalid values.
*/
public static Message Decode(byte[] binMessage, int offset, int arrayLen)
{
arrayLen = Math.Min(binMessage.Length, arrayLen);
if(binMessage == null || arrayLen - offset < Message.HEADER_LENGTH)
throw new StunException(StunException.ILLEGAL_ARGUMENT,
"The given binary array is not a valid StunMessage");
int messageType = (int)(((binMessage[offset++]<<8) & 0xff00) | (binMessage[offset++]&0xFF));
int mti = (int) messageType;
Message message;
if (Message.IsResponseType(messageType))
{
message = new Response();
}
else
{
message = new Request();
}
message.SetMessageType(messageType);
int length = (int)(((binMessage[offset++]<<8) & 0xff00) | (binMessage[offset++]&0xFF));
if(arrayLen - offset - TRANSACTION_ID_LENGTH < length)
throw new StunException(StunException.ILLEGAL_ARGUMENT,
"The given binary array does not seem to "
+"contain a whole StunMessage");
byte[] tranID = new byte[TRANSACTION_ID_LENGTH];
for (int x = 0; x < TRANSACTION_ID_LENGTH; x++)
{
tranID[x] = binMessage[offset + x];
}
message.SetTransactionID(tranID);
offset+=TRANSACTION_ID_LENGTH;
while(offset - Message.HEADER_LENGTH< length)
{
Attribute att = AttributeDecoder.decode(binMessage,
offset,
(length - offset));
if (att != null)
{
message.AddAttribute(att);
offset += att.GetDataLength() + Attribute.HEADER_LENGTH;
}
else
{
offset += Attribute.HEADER_LENGTH;
}
}
return message;
}
