public void connect(InetSocketAddress destAddress)
{
if (VpnServiceHelper.protect(mInnerChannel.Socket()))
{
mDestAddress = destAddress;
mInnerChannel.Register(mSelector, Operations.Connect, this);
mInnerChannel.Connect(mServerEP);
Debug.WriteLine($"Connecting to {mServerEP}");
}
else
{
throw new Exception("VPN protect socket failed.");
}
}
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);
}
internal SocketChannel AcceptServerSideChannel(SocketChannel localServer)
{
var promise = new TaskCompletionSource <Socket>();
var task = promise.Task;
localServer.Socket.Listen(100);
localServer.Socket.BeginAccept(ar => promise.SetResult(localServer.Socket.EndAccept(ar)), null);
Selector.Send(ConnectionActor, SelectionHandler.ChannelConnectable.Instance);
task.Wait();
var channel = new SocketChannel(task.Result);
channel.Register(ChannelProbe, SocketAsyncOperation.None);
return(channel);
}
public void Register(SocketChannel channel, SocketAsyncOperation?initialOps, IActorRef channelActor)
{
channel.Register(channelActor, initialOps);
RegisterCallReceiver.Ref.Tell(new TcpConnectionSpec.Registration(channel, initialOps));
}
private void processACK(TCB tcb, TCPHeader tcpHeader, ByteBuffer payloadBuffer, ByteBuffer responseBuffer)
{
try
{
int payloadSize = payloadBuffer.Limit() - payloadBuffer.Position();
lock (tcb)
{
SocketChannel outputChannel = tcb.channel;
if (tcb.status == TCB.TCBStatus.SYN_RECEIVED)
{
tcb.status = TCB.TCBStatus.ESTABLISHED;
selector.Wakeup();
tcb.selectionKey = outputChannel.Register(selector, SelectionKey.OpRead, tcb);
tcb.waitingForNetworkData = true;
}
else if (tcb.status == TCB.TCBStatus.LAST_ACK)
{
CloseCleanly(tcb, responseBuffer);
return;
}
if (payloadSize == 0)
{
return; // Empty ACK, ignore
}
if (!tcb.waitingForNetworkData)
{
selector.Wakeup();
// tcb.selectionKey.InterestOps(SelectionKey.OpRead);
tcb.selectionKey.InterestOps();
tcb.waitingForNetworkData = true;
}
// Forward to remote server
try
{
while (payloadBuffer.HasRemaining)
{
outputChannel.Write(payloadBuffer);
}
}
catch (IOException e)
{
Log.Error(TAG, "Network write error: " + tcb.ipAndPort, e);
SendRST(tcb, payloadSize, responseBuffer);
return;
}
// TODO: We don't expect out-of-order packets, but verify
tcb.myAcknowledgementNum = tcpHeader.sequenceNumber + payloadSize;
tcb.theirAcknowledgementNum = tcpHeader.acknowledgementNumber;
Packet referencePacket = tcb.referencePacket;
referencePacket.updateTCPBuffer(responseBuffer, (byte)TCPHeader.ACK, tcb.mySequenceNum, tcb.myAcknowledgementNum, 0);
}
outputQueue.Offer(responseBuffer);
}
catch (Exception ex)
{
System.Console.WriteLine(ex.Message);
}
}