/// <summary>
/// Start listener at selected port, accept connections and create remote socket. This function is blocking one.
/// </summary>
/// <param name="listenerInterface">local, client side interface</param>
/// <param name="outgoingInterface">local, remote server side interface</param>
/// <param name="listenerPort">port for both interfaces</param>
/// <param name="listNo">listener number</param>
public static void RunListener(IPAddress listenerInterface, int listenerPort)
{
listeners = ArrayList.Synchronized(listeners);
sockets = ArrayList.Synchronized(sockets);
TcpListener listener = new TcpListener(listenerInterface, listenerPort);
listeners.Add(listener);
listener.Start();
Console.WriteLine("started at {0}:{1}", listenerInterface.ToString(), listenerPort);
while (true)
{
Socket incoming_socket = listener.AcceptSocket();
var endPoint = (IPEndPoint)incoming_socket.RemoteEndPoint;
IPAddress outgoingInterface = endPoint.Address;
int listNo = endPoint.Port;
Console.WriteLine("listener {0} is waiting for a new client", listNo);
Console.WriteLine("listener {0}: client connected", listNo);
// connecting remote host
Console.WriteLine("listener {0} is connecting to remote host {1}:{2}", listNo, TARGET_IPADDR, listenerPort);
Socket remote_socket = ConnectSocket(new IPEndPoint(outgoingInterface, 0), TARGET_IPADDR, listenerPort);
if (remote_socket == null)
{
Console.WriteLine("listener {0}: outgoing connection failed", listNo);
continue;
}
Console.WriteLine("listener {0}: connected to remote host {1}:{2}", listNo, TARGET_IPADDR, listenerPort);
// begin receive on input
SocketStateObj iso = new SocketStateObj(incoming_socket, remote_socket);
sockets.Add(iso);
incoming_socket.BeginReceive(iso.buffer, 0, SocketStateObj.BUFF_SIZE, SocketFlags.None,
new AsyncCallback(Read_Callback), iso);
// begin receive on output
SocketStateObj oso = new SocketStateObj(remote_socket, incoming_socket);
sockets.Add(oso);
remote_socket.BeginReceive(oso.buffer, 0, SocketStateObj.BUFF_SIZE, SocketFlags.None,
new AsyncCallback(Read_Callback), oso);
}
}
private static void Read_Callback(IAsyncResult ar)
{
Socket s1 = null;
Socket s2 = null;
try
{
// retrieve SocketStateObj
SocketStateObj so = (SocketStateObj)ar.AsyncState;
s1 = so.in_socket;
s2 = so.out_socket;
int count = s1.EndReceive(ar);
if (count > 0)
{
// copy of buffer data
byte[] tmpbuff = new byte[PACKET_BUFFSIZE];
so.buffer.CopyTo(tmpbuff, 0);
// async. wait for next packet
s1.BeginReceive(so.buffer, 0, SocketStateObj.BUFF_SIZE, SocketFlags.None,
new AsyncCallback(Read_Callback), so);
// <-- packet filtering -->
#region show packet info
Console.ForegroundColor = ConsoleColor.Cyan;
Console.WriteLine("[{0}] packet {1} -> S: {2} D: {3} len: {4}",
DateTime.Now.ToString("HH:mm:ss"),
packet_no++,
s2.LocalEndPoint.ToString(),
s1.LocalEndPoint.ToString(),
count);
Console.ResetColor();
#endregion
// send packet to destination (if not filtered)
s2.Send(tmpbuff, 0, count, SocketFlags.None);
// <-- packet injection or re-sending -->
}
else
{
// close connections if packet has empty data
Console.WriteLine("connection {0} <-> {1} closed", s2.LocalEndPoint.ToString(), s1.LocalEndPoint.ToString());
s1.Close();
s2.Close();
}
}
catch (Exception ex)
{
// <-- socket exception handling code -->
//Console.WriteLine("Read_Callback exception: {0}", ex.Message);
try
{
s1.Close();
s2.Close();
}
catch (Exception) { }
}
}
/// <summary>
/// Start listener at selected port, accept connections and create remote socket. This function is blocking one.
/// </summary>
/// <param name="listenerInterface">local, client side interface</param>
/// <param name="outgoingInterface">local, remote server side interface</param>
/// <param name="listenerPort">port for both interfaces</param>
/// <param name="listNo">listener number</param>
public static void RunListener(IPAddress listenerInterface, int listenerPort)
{
listeners = ArrayList.Synchronized(listeners);
sockets = ArrayList.Synchronized(sockets);
TcpListener listener = new TcpListener(listenerInterface, listenerPort);
listeners.Add(listener);
listener.Start();
Console.WriteLine("started at {0}:{1}", listenerInterface.ToString(), listenerPort);
while (true)
{
Socket incoming_socket = listener.AcceptSocket();
var endPoint = (IPEndPoint)incoming_socket.RemoteEndPoint;
IPAddress outgoingInterface = endPoint.Address;
int listNo = endPoint.Port;
Console.WriteLine("listener {0} is waiting for a new client", listNo);
Console.WriteLine("listener {0}: client connected", listNo);
// connecting remote host
Console.WriteLine("listener {0} is connecting to remote host {1}:{2}", listNo, TARGET_IPADDR, listenerPort);
Socket remote_socket = ConnectSocket(new IPEndPoint(outgoingInterface, 0), TARGET_IPADDR, listenerPort);
if (remote_socket == null)
{
Console.WriteLine("listener {0}: outgoing connection failed", listNo);
continue;
}
Console.WriteLine("listener {0}: connected to remote host {1}:{2}", listNo, TARGET_IPADDR, listenerPort);
// begin receive on input
SocketStateObj iso = new SocketStateObj(incoming_socket, remote_socket);
sockets.Add(iso);
incoming_socket.BeginReceive(iso.buffer, 0, SocketStateObj.BUFF_SIZE, SocketFlags.None,
new AsyncCallback(Read_Callback), iso);
// begin receive on output
SocketStateObj oso = new SocketStateObj(remote_socket, incoming_socket);
sockets.Add(oso);
remote_socket.BeginReceive(oso.buffer, 0, SocketStateObj.BUFF_SIZE, SocketFlags.None,
new AsyncCallback(Read_Callback), oso);
}
}
