feat: Added login state protocol version check

Author: Andcool-Systems

README.md

@@ -97,14 +97,14 @@ server_ip = "localhost"
 support_1_19 = false
 
 [server.config]
-# Minecraft server name
+# Minecraft server name (used for internal auth; can be empty)
 server_name = "mc-oauth-rs"
 
 # Protocol version (`0` for auto)
-# Used only during the server ping and is ignored when trying to connect. If set to 0, the protocol version that the client uses will be applied.
+# If set to 0, the protocol version that the client uses will be applied.
 protocol = 0
 
-# Minecraft version string
+# Minecraft version string (In fact, it's just a stub)
 version = "1.21"
 
 # Session Auth URL  
@@ -141,6 +141,9 @@ using_proxy = "§cYou are using a proxy!"
 
 # Message for internal server error
 internal_error = "§cSorry, internal server error occurred"
+
+# Message for unsupported client version
+unsupported_client_version = "§cYou are using unsupported version of client!"
 ```
 
 

config.example.toml

@@ -28,3 +28,4 @@ success = "Hello, §6{{NAME}}§r! Your code is: §a{{CODE}}"
 bad_session = "§cFailed to login: Invalid session (Try restarting your game and the launcher)"
 using_proxy = "§cYou are using a proxy!"
 internal_error = "§cSorry, internal server error occurred"
+unsupported_client_version = "§cYou are using unsupported version of client!"

src/config/types.rs

@@ -103,4 +103,7 @@ pub struct Messages {
 
     /// Message for internal server error
     pub internal_error: String,
+
+    /// Message for unsupported client version
+    pub unsupported_client_version: String,
 }

src/handlers/handshake.rs

@@ -30,6 +30,19 @@ impl MinecraftServer {
             }
         }
 
+        // Check client's protocol version
+        let server_proto_ver = self.config.server.config.protocol;
+        if let NextStateEnum::Login = self.session.next_state {
+            if server_proto_ver.ne(&0) && self.session.proto_ver.ne(&server_proto_ver) {
+                self.send_disconnect(self.config.messages.unsupported_client_version.clone())
+                    .await?;
+                return Err(Error::msg(format!(
+                    "Unsupported client version! Server: {}, client: {}",
+                    server_proto_ver, self.session.proto_ver
+                )));
+            }
+        }
+
         Ok(())
     }
 }