private void SendResponse(IPEndPoint remote, NatNegMessage message)
{
byte[] response = message.ToBytes();
Log(Category, "Sending response " + message.ToString() + " to " + remote.ToString());
Log(Category, "(Response bytes: " + string.Join(" ", response.Select((b) => { return(b.ToString("X2")); }).ToArray()) + ")");
_socket.SendTo(response, remote);
}
private void OnDataReceived(object sender, SocketAsyncEventArgs e)
{
/*
* Connection Protocol
*
* From http://wiki.tockdom.com/wiki/MKWii_Network_Protocol/Server/mariokartwii.natneg.gs.nintendowifi.net
*
* The NATNEG communication to enable a peer to peer communication is is done in the following steps:
*
* Both clients (called guest and host to distinguish them) exchange an unique natneg-id. In all observed Wii games this communication is done using Server MS and Server MASTER.
* Both clients sends independent of each other a sequence of 4 INIT packets to the NATNEG servers. The sequence number goes from 0 to 3. The guest sets the host_flag to 0 and the host to 1. The natneg-id must be the same for all packets.
* Packet 0 (sequence number 0) is send from the public address to server NATNEG1. This public address is later used for the peer to peer communication.
* Packet 1 (sequence number 1) is send from the communication address (usually an other port than the public address) to server NATNEG1.
* Packet 2 (sequence number 2) is send from the communication address to server NATNEG2 (any kind of fallback?).
* Packet 3 (sequence number 3) is send from the communication address to server NATNEG3 (any kind of fallback?).
* Each INIT packet is answered by an INIT_ACK packet as acknowledge to the original sender.
* If server NATNEG1 have received all 4 INIT packets with sequence numbers 0 and 1 (same natneg-id), then it sends 2 CONNECT packets:
* One packet is send to the communication address of the guest. The packet contains the public address of the host as data.
* The other packet is send to the communication address of the host. The packet contains the public address of the quest as data.
* Both clients send back a CONNECT_ACK packet to NATNEG1 as acknowledge.
* Both clients start peer to peer communication using the public addresses.
*
* C implementation:
* See http://aluigi.altervista.org/papers/gsnatneg.c
*
* Game names and game keys:
* Civilization IV: Beyond the Sword civ4bts Cs2iIq
* Mario Kart Wii (Wii) mariokartwii 9r3Rmy
*
*/
try {
IPEndPoint remote = (IPEndPoint)e.RemoteEndPoint;
byte[] receivedBytes = new byte[e.BytesTransferred];
Array.Copy(e.Buffer, e.Offset, receivedBytes, 0, e.BytesTransferred);
NatNegMessage message = null;
try
{
message = NatNegMessage.ParseData(receivedBytes);
}
catch (Exception ex)
{
LogError(Category, ex.ToString());
}
if (message == null)
{
Log(Category, "Received unknown data " + string.Join(" ", receivedBytes.Select((b) => { return(b.ToString("X2")); }).ToArray()) + " from " + remote.ToString());
}
else
{
Log(Category, "Received message " + message.ToString() + " from " + remote.ToString());
Log(Category, "(Message bytes: " + string.Join(" ", receivedBytes.Select((b) => { return(b.ToString("X2")); }).ToArray()) + ")");
if (message.RecordType == 0)
{
// INIT, return INIT_ACK
message.RecordType = 1;
SendResponse(remote, message);
if (message.SequenceId > 1)
{
// Messages sent to natneg2 and natneg3, they only require an INIT_ACK. Used by client to determine NAT mapping mode?
}
else
{
// Collect data and send CONNECT messages if you have two peers initialized with all necessary data
if (!_Clients.ContainsKey(message.ClientId))
{
_Clients[message.ClientId] = new NatNegClient();
}
NatNegClient client = _Clients[message.ClientId];
client.ClientId = message.ClientId;
bool isHost = message.Hoststate > 0;
NatNegPeer peer = isHost ? client.Host : client.Guest;
if (peer == null)
{
peer = new NatNegPeer();
if (isHost)
{
client.Host = peer;
}
else
{
client.Guest = peer;
}
}
peer.IsHost = isHost;
if (message.SequenceId == 0)
{
peer.PublicAddress = remote;
}
else
{
peer.CommunicationAddress = remote;
}
if (client.Guest != null && client.Guest.CommunicationAddress != null && client.Guest.PublicAddress != null && client.Host != null && client.Host.CommunicationAddress != null && client.Host.PublicAddress != null)
{
/* If server NATNEG1 have received all 4 INIT packets with sequence numbers 0 and 1 (same natneg-id), then it sends 2 CONNECT packets:
* One packet is send to the communication address of the guest. The packet contains the public address of the host as data.
* The other packet is send to the communication address of the host. The packet contains the public address of the quest as data.
*/
// Remove client from dictionary
NatNegClient removed = null;
_Clients.TryRemove(client.ClientId, out removed);
message.RecordType = 5;
message.Error = 0;
message.GotData = 0x42;
message.ClientPublicIPAddress = NatNegMessage._toIpAddress(client.Host.PublicAddress.Address.GetAddressBytes());
message.ClientPublicPort = (ushort)client.Host.PublicAddress.Port;
SendResponse(client.Guest.CommunicationAddress, message);
message.ClientPublicIPAddress = NatNegMessage._toIpAddress(client.Guest.PublicAddress.Address.GetAddressBytes());
message.ClientPublicPort = (ushort)client.Guest.PublicAddress.Port;
SendResponse(client.Host.CommunicationAddress, message);
Log(Category, "Sent connect messages to peers with clientId " + client.ClientId + " connecting host " + client.Host.PublicAddress.ToString() + " and guest " + client.Guest.PublicAddress.ToString());
}
}
}
else if (message.RecordType == 13)
{
// REPORT, return REPORT_ACK
message.RecordType = 14;
SendResponse(remote, message);
}
}
} catch (Exception ex) {
LogError(Category, ex.ToString());
}
WaitForData();
}