From 28b3a63da8c038ead4b9b38869322d5f1acdabed Mon Sep 17 00:00:00 2001
From: raven <citrons@mondecitronne.com>
Date: Sun, 22 Mar 2026 22:10:59 -0500
Subject: reject non-CPE clients

---
 server/server.go | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/server/server.go b/server/server.go
index 213bd64..a434aee 100644
--- a/server/server.go
+++ b/server/server.go
@@ -439,18 +439,11 @@ func (cl *client) performHandshake(conn net.Conn, srvInfo ServerInfo) {
 	}
 	switch pid := packet.(type) {
 	case *classic.PlayerId:
-		if pid.Version != 7 {
-			cl.disconnect(
-				"Please join on protocol version 7 (Minecraft Classic 0.30 / "+
-				"ClassiCube)",
-			)
+		if pid.Version != 7 || pid.Ext != classic.UseCpe {
+			cl.disconnect("Please join in a CPE client (i.e. ClassiCube)")
+			return
 		}
 		cl.username = classic.UnpadString(pid.Username)
-		if pid.Ext == classic.UseCpe {
-			if !cl.cpeHandshake(conn, ext) {
-				return
-			}
-		}
 	default:
 		cl.disconnect("Expected handshake")
 		return
@@ -459,6 +452,9 @@ func (cl *client) performHandshake(conn net.Conn, srvInfo ServerInfo) {
 		cl.disconnect("Invalid player name")
 		return
 	}
+	if !cl.cpeHandshake(conn, ext) {
+		return
+	}
 
 	err = classic.WritePacket(conn, &classic.ServerId {
 		Version: 7,
-- 
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