diff -r 0eedc17055a0 -r cdf69667593b gameServer2/src/server/handlers/lobby.rs
--- a/gameServer2/src/server/handlers/lobby.rs	Thu Jun 14 16:44:27 2018 -0400
+++ b/gameServer2/src/server/handlers/lobby.rs	Mon Jun 18 09:22:53 2018 -0400
@@ -1,38 +1,60 @@
 use mio;
 
-use server::server::HWServer;
-use server::actions::Action;
-use server::actions::Action::*;
-use protocol::messages::HWProtocolMessage;
-use protocol::messages::HWServerMessage::*;
+use server::{
+    server::HWServer,
+    actions::{Action, Action::*}
+};
+use protocol::messages::{
+    HWProtocolMessage,
+    HWServerMessage::*
+};
+use utils::is_name_illegal;
 
 pub fn handle(server: &mut HWServer, token: usize, message: HWProtocolMessage) {
     use protocol::messages::HWProtocolMessage::*;
     match message {
+        CreateRoom(name, password) => {
+            let actions =
+                if is_name_illegal(&name) {
+                    vec![Warn("Illegal room name! A room name must be between 1-40 characters long, must not have a trailing or leading space and must not have any of these characters: $()*+?[]^{|}".to_string())]
+                } else if server.has_room(&name) {
+                    vec![Warn("A room with the same name already exists.".to_string())]
+                } else {
+                    let flags_msg = ClientFlags(
+                        "+hr".to_string(),
+                        vec![server.clients[token].nick.clone()]);
+                    vec![AddRoom(name, password),
+                         SendMe(flags_msg)]
+                };
+            server.react(token, actions);
+        },
         Chat(msg) => {
             let chat_msg = ChatMsg(server.clients[token].nick.clone(), msg);
             server.react(token, vec![SendAllButMe(chat_msg)]);
         },
-        CreateRoom(name, password) => {
-            let room_exists = server.rooms.iter().find(|&(_, r)| r.name == name).is_some();
-            if room_exists {
-                server.react(token, vec![Warn("Room exists".to_string())]);
-            } else {
-                let flags_msg = ClientFlags("+hr".to_string(), vec![server.clients[token].nick.clone()]);
-                {
-                    let c = &mut server.clients[token];
-                    c.is_master = true;
-                    c.is_ready = true;
-                    c.is_joined_mid_game = false;
-                }
-                server.react(token, vec![
-                    AddRoom(name, password)
-                    , SendMe(flags_msg)
-                    ]);
+        JoinRoom(name, password) => {
+            let actions;
+            {
+                let room = server.rooms.iter().find(|(_, r)| r.name == name);
+                let room_id = room.map(|(_, r)| r.id);
+                let nicks = server.clients.iter()
+                    .filter(|(_, c)| c.room_id == room_id)
+                    .map(|(_, c)| c.nick.clone())
+                    .collect();
+                let c = &mut server.clients[token];
+                actions = match room {
+                    None => vec![Warn("No such room.".to_string())],
+                    Some((_, r)) => {
+                        if c.protocol_number != r.protocol_number {
+                            vec![Warn("Room version incompatible to your Hedgewars version!".to_string())]
+                        } else {
+                            vec![MoveToRoom(r.id),
+                                 SendMe(RoomJoined(nicks))]
+                        }
+                    }
+                };
             }
-        },
-        Join(name, password) => {
-
+            server.react(token, actions);
         },
         List => warn!("Deprecated LIST message received"),
         _ => warn!("Incorrect command in lobby state"),