New login process + a little bit of cleanup

No reliability required :) Will get to the client soon

Subsurface/Source/Networking/GameServerLogin.cs

@@ -13,6 +13,8 @@ namespace Barotrauma.Networking
         public NetConnection Connection;
         public int Nonce;
 
+        public int failedAttempts;
+
         public float AuthTimer;
 
         public UnauthenticatedClient(NetConnection connection, int nonce)
@@ -21,12 +23,172 @@ namespace Barotrauma.Networking
             Nonce = nonce;
 
             AuthTimer = 5.0f;
+
+            failedAttempts = 0;
         }
     }
 
     partial class GameServer : NetworkMember, IPropertyObject
     {
-        List<UnauthenticatedClient> unauthenticatedClients = new List<UnauthenticatedClient>();
-        
+        List<UnauthenticatedClient> unauthenticatedClients = new List<UnauthenticatedClient>();
+
+        private void ClientPasswordRequest(NetConnection conn)
+        {
+            //client wants to know if server requires password
+
+            if (ConnectedClients.Count > MaxPlayers)
+            {
+                //server is full, can't allow new connection
+                conn.Disconnect("Server full");
+            }
+
+            if (ConnectedClients.Find(c => c.Connection == conn) != null)
+            {
+                //this client has already been authenticated
+                return;
+            }
+            UnauthenticatedClient unauthClient = unauthenticatedClients.Find(uc => uc.Connection == conn);
+            if (unauthClient == null)
+            {
+                //new client, generate nonce and add to unauth queue
+                int nonce = CryptoRandom.Instance.Next();
+                unauthClient = new UnauthenticatedClient(conn, nonce);
+                unauthenticatedClients.Add(unauthClient);
+            }
+            //if the client is already in the queue, getting another unauth request means that our response was lost; resend
+            NetOutgoingMessage nonceMsg = server.CreateMessage();
+            if (string.IsNullOrEmpty(password))
+            {
+                nonceMsg.Write(false); //false = no password
+            }
+            else
+            {
+                nonceMsg.Write(true); //true = password
+                nonceMsg.Write(unauthClient.Nonce); //here's nonce, encrypt with this
+            }
+            server.SendMessage(nonceMsg, conn, NetDeliveryMethod.Unreliable);
+        }
+
+        private void ClientInitialize(NetIncomingMessage inc)
+        {
+            if (ConnectedClients.Find(c => c.Connection == inc.SenderConnection) != null)
+            {
+                //this client was already authenticated
+                //another init request means they didn't get any update packets yet
+                return;
+            }
+
+            UnauthenticatedClient unauthClient = unauthenticatedClients.Find(uc => uc.Connection == inc.SenderConnection);
+            if (unauthClient == null)
+            {
+                //client did not ask for nonce first, can't authorize
+                inc.SenderConnection.Disconnect("Client did not properly request authentication.");
+                return;
+            }
+
+            if (!string.IsNullOrEmpty(password))
+            {
+                //decrypt message and compare password
+                string saltedPw = password;
+                saltedPw = saltedPw + Convert.ToString(unauthClient.Nonce);
+                saltedPw = Encoding.UTF8.GetString(NetUtility.ComputeSHAHash(Encoding.UTF8.GetBytes(saltedPw)));
+                NetEncryption algo = new NetXtea(server, saltedPw);
+                inc.Decrypt(algo);
+                string clPw = inc.ReadString();
+                if (clPw != saltedPw)
+                {
+                    unauthClient.failedAttempts++;
+                    if (unauthClient.failedAttempts > 3)
+                    {
+                        //disconnect after too many failed attempts
+                        unauthClient.Connection.Disconnect("Too many failed login attempts.");
+                        unauthenticatedClients.Remove(unauthClient);
+                        unauthClient = null;
+                        return;
+                    }
+                    else
+                    {
+                        //not disconnecting the player here, because they'll still use the same connection and nonce if they try logging in again
+                        NetOutgoingMessage reject = server.CreateMessage();
+                        reject.Write((byte)ServerPacketHeader.AUTH_FAILURE);
+                        reject.Write("Wrong password!");
+                        server.SendMessage(reject, unauthClient.Connection, NetDeliveryMethod.Unreliable);
+                        return;
+                    }
+                }
+            }
+            string clVersion = inc.ReadString();
+            string clPackageName = inc.ReadString();
+            string clPackageHash = inc.ReadString();
+
+            if (clVersion != GameMain.Version.ToString())
+            {
+                inc.SenderConnection.Disconnect("Version " + GameMain.Version + " required to connect to the server (Your version: " + clVersion + ")");
+                unauthenticatedClients.Remove(unauthClient);
+                unauthClient = null;
+                DebugConsole.NewMessage(name + " couldn't join the server (wrong game version)", Color.Red);
+                return;
+            }
+            if (clPackageName != GameMain.SelectedPackage.Name)
+            {
+                inc.SenderConnection.Disconnect("Your content package (" + clPackageName + ") doesn't match the server's version (" + GameMain.SelectedPackage.Name + ")");
+                unauthenticatedClients.Remove(unauthClient);
+                unauthClient = null;
+                DebugConsole.NewMessage(name + " couldn't join the server (wrong content package name)", Color.Red);
+                return;
+            }
+            if (clPackageHash != GameMain.SelectedPackage.MD5hash.Hash)
+            {
+                unauthClient.Connection.Disconnect("Your content package (MD5: " + clPackageHash + ") doesn't match the server's version (MD5: " + GameMain.SelectedPackage.MD5hash.Hash + ")");
+                unauthenticatedClients.Remove(unauthClient);
+                unauthClient = null;
+                DebugConsole.NewMessage(name + " couldn't join the server (wrong content package hash)", Color.Red);
+                return;
+            }
+
+            string clName = Client.SanitizeName(inc.ReadString());
+            if (string.IsNullOrWhiteSpace(clName))
+            {
+                unauthClient.Connection.Disconnect("You need a name.");
+                unauthenticatedClients.Remove(unauthClient);
+                unauthClient = null;
+                return;
+            }
+            if (!Client.IsValidName(name))
+            {
+                unauthClient.Connection.Disconnect("Your name contains illegal symbols.");
+                unauthenticatedClients.Remove(unauthClient);
+                unauthClient = null;
+                return;
+            }
+            Client nameTaken = ConnectedClients.Find(c => c.name.ToLower() == clName.ToLower());
+            if (nameTaken != null)
+            {
+                if (nameTaken.Connection.RemoteEndPoint.Address.ToString() == inc.SenderEndPoint.Address.ToString())
+                {
+                    //both name and IP address match, replace this player's connection
+                    nameTaken.Connection.Disconnect("Your session was taken by a new connection on the same IP address.");
+                    nameTaken.Connection = unauthClient.Connection;
+                    unauthenticatedClients.Remove(unauthClient);
+                    unauthClient = null;
+                    return;
+                }
+                else
+                {
+                    //can't authorize this client
+                    unauthClient.Connection.Disconnect("That name is taken.");
+                    unauthenticatedClients.Remove(unauthClient);
+                    unauthClient = null;
+                    return;
+                }
+            }
+
+            //new client
+            Client newClient = new Client(clName, GetNewClientID());
+            newClient.Connection = unauthClient.Connection;
+            unauthenticatedClients.Remove(unauthClient);
+            unauthClient = null;
+            return;
+        }
     }
 }