/// <summary>Stops allowing traversal of routers/firewalls to this host.</summary>
/// <remarks>This will stop this NAT traversal session.</remarks>
public void Disable()
{
if (!disabled)
{
// stop notification thread by sending a message from this local endpoint to itself
byte[] emptyDatagram = new byte[0];
PortSpoofing.Send(LocalEndPoint, LocalEndPoint, emptyDatagram);
disabled = true;
}
}
/// <summary>Notifies NAT traversal service that a player has joined (for statistical purpose).</summary>
/// <param name="serverPrivatePort">The private port of the host.</param>
/// <param name="clientIp">The IP address of the client.</param>
/// <param name="clientPort">The port of the client.</param>
public unsafe static void NotifyPlayerHasJoined(INatTraversalSession session, IPAddress clientIp, int clientPort)
{
try {
// send "player_has_joined" message, from the same port as DirectPlay (spoofed)
// connect to service to determine end points
using (Socket dummySocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp)) {
dummySocket.Connect(natTraversalServiceUrl, natTraversalServicePort);
IPEndPoint serviceEndPoint = (IPEndPoint)dummySocket.RemoteEndPoint;
IPEndPoint localEndPoint = (IPEndPoint)dummySocket.LocalEndPoint;
IPEndPoint spoofedEndPoint = new IPEndPoint(localEndPoint.Address, ((NatTraversalSession)session).PrivatePort);
MsgPlayerHasJoined msgPlayerHasJoined = new MsgPlayerHasJoined(session.SessionId, clientIp, (ushort)clientPort);
byte[] datagram = new byte[sizeof(MsgPlayerHasJoined)];
for (int i = 0; i < datagram.Length; ++i)
{
datagram[i] = ((byte *)&msgPlayerHasJoined)[i];
}
PortSpoofing.Send(spoofedEndPoint, serviceEndPoint, datagram);
}
} catch { }
}
private static void keepAlive(object state)
{
KeepAliveSettings settings = (KeepAliveSettings)state;
PortSpoofing.Send(settings.SpoofedLocalEndPoint, settings.ServiceEndPoint, settings.Datagram);
}
private static unsafe void notificationLoop(object natTraversalSession)
{
NatTraversalSession session = (NatTraversalSession)natTraversalSession;
Timer keepAliveTimer = null;
try {
IPEndPoint serviceEndPoint = null;
// connect to service to open a port on the NAT devices
using (Socket notificationSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp)) {
notificationSocket.Connect(natTraversalServiceUrl, natTraversalServicePort);
serviceEndPoint = (IPEndPoint)notificationSocket.RemoteEndPoint;
session.LocalEndPoint = (IPEndPoint)notificationSocket.LocalEndPoint;
}
// create a new socket in listening mode using the port just opened
using (Socket notificationSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp)) {
notificationSocket.ReceiveTimeout = 1000;
notificationSocket.Bind(session.LocalEndPoint);
// send "open notification channel" message
{
MsgOpenNotificationChannel msg = new MsgOpenNotificationChannel(session.SessionId);
byte[] datagram = new byte[sizeof(MsgOpenNotificationChannel)];
for (int i = 0; i < datagram.Length; ++i)
{
datagram[i] = ((byte *)&msg)[i];
}
notificationSocket.SendTo(datagram, serviceEndPoint);
}
while (true)
{
// block until a message is received or 1 second has elapsed
EndPoint any = new IPEndPoint(IPAddress.Any, 0);
byte[] bytesReceived = new byte[1024];
int bytesReceivedLength = notificationSocket.ReceiveFrom(bytesReceived, ref any);
IPEndPoint remoteEndPoint = (IPEndPoint)any;
// test for stop condition: a message send from this local endpoint to itself
if (remoteEndPoint.Equals(session.LocalEndPoint))
{
break;
}
else if (remoteEndPoint.Equals(serviceEndPoint))
{
// handle the message
if (bytesReceivedLength >= 3 && bytesReceived[0] == 'z' && bytesReceived[1] == 't')
{
switch (bytesReceived[2])
{
case (byte)MessageType.AckOpenNotificationChannel:
if (bytesReceivedLength == sizeof(MsgAckOpenNotificationChannel))
{
MsgAckOpenNotificationChannel msg = new MsgAckOpenNotificationChannel();
for (int i = 0; i < sizeof(MsgAckOpenNotificationChannel); ++i)
{
((byte *)&msg)[i] = bytesReceived[i];
}
// handle MsgAckOpenNotificationChannel
// send "host" message, from the same port as DirectPlay (spoofed)
IPEndPoint spoofedEndPoint = new IPEndPoint(session.LocalEndPoint.Address, session.PrivatePort);
MsgHost msgHost = new MsgHost(session.SessionId, session.LocalEndPoint.Address, (ushort)session.PrivatePort);
byte[] datagram = new byte[sizeof(MsgHost)];
for (int i = 0; i < datagram.Length; ++i)
{
datagram[i] = ((byte *)&msgHost)[i];
}
PortSpoofing.Send(spoofedEndPoint, serviceEndPoint, datagram);
}
break;
case (byte)MessageType.AckHost:
if (bytesReceivedLength == sizeof(MsgAckHost))
{
if (keepAliveTimer == null) // ignore if already handled
{
MsgAckHost msg = new MsgAckHost();
for (int i = 0; i < sizeof(MsgAckHost); ++i)
{
((byte *)&msg)[i] = bytesReceived[i];
}
// handle MsgAckHost
// record public address/port
session.PublicIpAddress = new IPAddress((uint)IPAddress.HostToNetworkOrder((int)msg.HostPublicIp)).ToString();
session.PublicPort = msg.HostPublicPort;
// notify main thread that NAT traversal is enabled
session.Enabled = true;
if (session.NatTraversalEnabled != null)
{
session.NatTraversalEnabled.Set();
}
// set reception so it can't time-out
notificationSocket.ReceiveTimeout = 0;
// send a keep alive message every 19 seconds
KeepAliveSettings settings = new KeepAliveSettings();
settings.SpoofedLocalEndPoint = session.LocalEndPoint;
settings.ServiceEndPoint = serviceEndPoint;
MsgKeepAlive msgKeepAlive = new MsgKeepAlive(session.SessionId);
settings.Datagram = new byte[sizeof(MsgKeepAlive)];
for (int i = 0; i < settings.Datagram.Length; ++i)
{
settings.Datagram[i] = ((byte *)&msgKeepAlive)[i];
}
keepAliveTimer = new Timer(new TimerCallback(keepAlive), settings, 19000, 19000);
}
}
break;
case (byte)MessageType.Connect:
if (bytesReceivedLength == sizeof(MsgConnect))
{
MsgConnect msg = new MsgConnect();
for (int i = 0; i < sizeof(MsgConnect); ++i)
{
((byte *)&msg)[i] = bytesReceived[i];
}
// handle MsgConnect
// punch hole targeting client's public and private addresses
IPAddress publicClientAddress = new IPAddress((uint)IPAddress.HostToNetworkOrder((int)msg.ClientPublicIp));
IPAddress privateClientAddress = new IPAddress((uint)IPAddress.HostToNetworkOrder((int)msg.ClientPrivateIp));
IPEndPoint spoofedEndPoint = new IPEndPoint(session.LocalEndPoint.Address, session.PrivatePort);
byte[] emptyDatagram = new byte[0];
PortSpoofing.Send(spoofedEndPoint, new IPEndPoint(publicClientAddress, msg.ClientPublicPort), emptyDatagram);
PortSpoofing.Send(spoofedEndPoint, new IPEndPoint(privateClientAddress, msg.ClientPrivatePort), emptyDatagram);
// send acknowledgement through notification channel
MsgAckConnect msgAckConnect = new MsgAckConnect(session.SessionId, publicClientAddress, msg.ClientPublicPort);
byte[] datagram = new byte[sizeof(MsgAckConnect)];
for (int i = 0; i < datagram.Length; ++i)
{
datagram[i] = ((byte *)&msgAckConnect)[i];
}
notificationSocket.SendTo(datagram, serviceEndPoint);
}
break;
}
}
}
}
}
} catch {
if (!session.Enabled && session.NatTraversalEnabled != null)
{
session.NatTraversalEnabled.Set();
}
} finally {
if (keepAliveTimer != null)
{
keepAliveTimer.Change(Timeout.Infinite, Timeout.Infinite);
keepAliveTimer.Dispose();
}
}
}
