private void ProcessConnect(SelectionKey key, List <SelectionKey> keyIterator)
{
TCB tcb = (TCB)key.Attachment();
Packet referencePacket = tcb.referencePacket;
try
{
if (tcb.channel.FinishConnect())
{
if (keyIterator[0] != null)
{
keyIterator.RemoveAt(0);
}
tcb.status = TCBStatus.SYN_RECEIVED;
// TODO: Set MSS for receiving larger packets from the device
ByteBuffer responseBuffer = ByteBufferPool.acquire();
referencePacket.updateTCPBuffer(responseBuffer, (byte)(Packet.TCPHeader.SYN | Packet.TCPHeader.ACK),
tcb.mySequenceNum, tcb.myAcknowledgementNum, 0);
outputQueue.Offer(responseBuffer);
tcb.mySequenceNum++; // SYN counts as a byte
//key.InterestOps(Operations.Read);
key.InterestOps();
}
}
catch (IOException e)
{
Log.Error(TAG, "Connection error: " + tcb.ipAndPort, e);
ByteBuffer responseBuffer = ByteBufferPool.acquire();
referencePacket.updateTCPBuffer(responseBuffer, (byte)Packet.TCPHeader.RST, 0, tcb.myAcknowledgementNum, 0);
outputQueue.Offer(responseBuffer);
TCB.CloseTCB(tcb);
}
}
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);
}
private void processInput(SelectionKey key, List <SelectionKey> keyIterator)
{
System.Console.WriteLine("TCP In");
try
{
if (keyIterator[0] != null)
{
keyIterator.RemoveAt(0);
}
ByteBuffer receiveBuffer = ByteBufferPool.acquire();
// Leave space for the header
receiveBuffer.Position(HEADER_SIZE);
TCB tcb = (TCB)key.Attachment();
lock (tcb)
{
Packet referencePacket = tcb.referencePacket;
SocketChannel inputChannel = (SocketChannel)key.Channel();
int readBytes;
try
{
readBytes = inputChannel.Read(receiveBuffer);
}
catch (IOException e)
{
Log.Error(TAG, "Network read error: " + tcb.ipAndPort, e);
referencePacket.updateTCPBuffer(receiveBuffer, (byte)Packet.TCPHeader.RST, 0, tcb.myAcknowledgementNum, 0);
outputQueue.Offer(receiveBuffer);
TCB.CloseTCB(tcb);
return;
}
if (readBytes == -1)
{
// End of stream, stop waiting until we push more data
//key.InterestOps(0);
key.InterestOps();
tcb.waitingForNetworkData = false;
if (tcb.status != TCBStatus.CLOSE_WAIT)
{
ByteBufferPool.Release(receiveBuffer);
return;
}
tcb.status = TCBStatus.LAST_ACK;
referencePacket.updateTCPBuffer(receiveBuffer, (byte)Packet.TCPHeader.FIN, tcb.mySequenceNum, tcb.myAcknowledgementNum, 0);
tcb.mySequenceNum++; // FIN counts as a byte
}
else
{
// XXX: We should ideally be splitting segments by MTU/MSS, but this seems to work without
referencePacket.updateTCPBuffer(receiveBuffer, (byte)(Packet.TCPHeader.PSH | Packet.TCPHeader.ACK),
tcb.mySequenceNum, tcb.myAcknowledgementNum, readBytes);
tcb.mySequenceNum += readBytes; // Next sequence number
receiveBuffer.Position(HEADER_SIZE + readBytes);
}
}
outputQueue.Offer(receiveBuffer);
}
catch (Java.Lang.Exception ex)
{
System.Console.WriteLine(ex.Message);
}
}
private void CloseCleanly(TCB tcb, ByteBuffer buffer)
{
ByteBufferPool.Release(buffer);
TCB.CloseTCB(tcb);
}
private void SendRST(TCB tcb, int prevPayloadSize, ByteBuffer buffer)
{
tcb.referencePacket.updateTCPBuffer(buffer, (byte)TCPHeader.RST, 0, tcb.myAcknowledgementNum + prevPayloadSize, 0);
outputQueue.Offer(buffer);
TCB.CloseTCB(tcb);
}