feat: 消息解码逻辑调整，解决issue-23存在问题

Author: meethigher

src/main/java/top/meethigher/proxy/tcp/mux/MuxMessageParser.java

@@ -44,11 +44,7 @@ public MuxMessageParser(Handler<MuxMessage> muxMessageHandler, NetSocket netSock
     protected void parse() {
         // 获取消息的预设总长度
         int totalLength = buf.getInt(lengthFieldOffset);
-        // 校验预设总长度
-        if (buf.length() < totalLength) {
-            return;
-        }
-        // 校验最大长度
+        // 校验消息预设总长度是否超过最大限制
         if (totalLength > maxLength) {
             log.warn("too many bytes in length field, {} > {}, connection {} -- {} will be closed",
                     totalLength, maxLength,
@@ -57,6 +53,10 @@ protected void parse() {
             netSocket.close();
             return;
         }
+        // 校验预设总长度
+        if (buf.length() < totalLength) {
+            return;
+        }
         // 校验类型编码是否在预设范围内
         if (totalLength >= (lengthFieldLength + typeFieldLength)) {
             short code = buf.getShort(lengthFieldLength);

src/main/java/top/meethigher/proxy/tcp/tunnel/codec/TunnelMessageParser.java

@@ -71,11 +71,7 @@ public void handle(Buffer buffer) {
     protected void parse() {
         // 获取消息的预设总长度
         int totalLength = buf.getInt(lengthFieldOffset);
-        // 校验预设总长度
-        if (buf.length() < totalLength) {
-            return;
-        }
-        // 校验最大长度
+        // 校验消息预设总长度是否超过最大限制
         if (totalLength > maxLength) {
             log.warn("too many bytes in length field, {} > {}, connection {} -- {} will be closed",
                     totalLength, maxLength,
@@ -84,6 +80,10 @@ protected void parse() {
             netSocket.close();
             return;
         }
+        // 校验预设总长度
+        if (buf.length() < totalLength) {
+            return;
+        }
         // 校验类型编码是否在预设范围内
         if (totalLength >= (lengthFieldLength + typeFieldLength)) {
             short code = buf.getShort(lengthFieldLength);