private void InitializeConnection(Java.Lang.String ipAndPort, InetAddress destinationAddress, int destinationPort,
Packet currentPacket, TCPHeader tcpHeader, ByteBuffer responseBuffer)
{
currentPacket.SwapSourceAndDestination();
if (tcpHeader.isSYN())
{
SocketChannel outputChannel = SocketChannel.Open();
outputChannel.ConfigureBlocking(false);
vpnService.Protect(outputChannel.Socket());
TCB tcb = new TCB(ipAndPort, random.NextInt(Short.MaxValue + 1), tcpHeader.sequenceNumber, tcpHeader.sequenceNumber + 1,
tcpHeader.acknowledgementNumber, outputChannel, currentPacket);
TCB.PutTCB(ipAndPort, tcb);
try
{
outputChannel.Connect(new InetSocketAddress(destinationAddress, destinationPort));
if (outputChannel.FinishConnect())
{
tcb.status = TCB.TCBStatus.SYN_RECEIVED;
// TODO: Set MSS for receiving larger packets from the device
currentPacket.updateTCPBuffer(responseBuffer, (byte)(TCPHeader.SYN | TCPHeader.ACK),
tcb.mySequenceNum, tcb.myAcknowledgementNum, 0);
tcb.mySequenceNum++; // SYN counts as a byte
}
else
{
tcb.status = TCB.TCBStatus.SYN_SENT;
selector.Wakeup();
tcb.selectionKey = outputChannel.Register(selector, SelectionKey.OpConnect, tcb);
return;
}
}
catch (IOException e)
{
Log.Error(TAG, "Connection error: " + ipAndPort, e);
currentPacket.updateTCPBuffer(responseBuffer, (byte)TCPHeader.RST, 0, tcb.myAcknowledgementNum, 0);
TCB.CloseTCB(tcb);
}
}
else
{
currentPacket.updateTCPBuffer(responseBuffer, (byte)TCPHeader.RST,
0, tcpHeader.sequenceNumber + 1, 0);
}
outputQueue.Offer(responseBuffer);
}
public void Run()
{
Log.Info(TAG, "Started");
try
{
Thread currentThread = Thread.CurrentThread();
while (true)
{
Packet currentPacket;
// TODO: Block when not connected
do
{
currentPacket = (Packet)inputQueue.Poll();
if (currentPacket != null)
{
break;
}
Thread.Sleep(10);
} while (!currentThread.IsInterrupted);
if (currentThread.IsInterrupted)
{
break;
}
ByteBuffer payloadBuffer = currentPacket.backingBuffer;
currentPacket.backingBuffer = null;
ByteBuffer responseBuffer = ByteBufferPool.acquire();
InetAddress destinationAddress = currentPacket.ip4Header.destinationAddress;
TCPHeader tcpHeader = currentPacket.tcpHeader;
int destinationPort = tcpHeader.destinationPort;
int sourcePort = tcpHeader.sourcePort;
Java.Lang.String ipAndPort = new Java.Lang.String(destinationAddress.HostAddress + ":" +
destinationPort + ":" + sourcePort);
System.Console.WriteLine("TCP Out: " + ipAndPort);
TCB tcb = TCB.GetTCB(ipAndPort);
if (tcb == null)
{
InitializeConnection(ipAndPort, destinationAddress, destinationPort,
currentPacket, tcpHeader, responseBuffer);
}
else if (tcpHeader.isSYN())
{
processDuplicateSYN(tcb, tcpHeader, responseBuffer);
}
else if (tcpHeader.isRST())
{
CloseCleanly(tcb, responseBuffer);
}
else if (tcpHeader.isFIN())
{
processFIN(tcb, tcpHeader, responseBuffer);
}
else if (tcpHeader.isACK())
{
processACK(tcb, tcpHeader, payloadBuffer, responseBuffer);
}
// XXX: cleanup later
if (responseBuffer.Position() == 0)
{
ByteBufferPool.Release(responseBuffer);
}
ByteBufferPool.Release(payloadBuffer);
}
}
catch (InterruptedException e)
{
Log.Info(TAG, "Stopping");
}
catch (IOException e)
{
Log.Error(TAG, e.ToString(), e);
}
finally
{
TCB.CloseAll();
}
}