[net][lwip] lwip hook functions are provided to provide greater flexibility for unknown Ethernet protocols

components/net/lwip/Kconfig

@@ -281,6 +281,10 @@ if RT_USING_LWIP
         endif
     endif
 
+    config RT_LWIP_ENABLE_USER_HOOKS
+        bool "Enable user-defined LWIP hooks"
+        default n
+
     menuconfig RT_LWIP_DEBUG
         bool "Enable lwIP Debugging Options"
         default n

components/net/lwip/port/lwipopts.h

@@ -654,4 +654,15 @@
 #endif
 #endif /* RT_USING_LWIP_VER_NUM >= 0x20000 */
 
+#if RT_LWIP_ENABLE_USER_HOOKS
+/**
+ * This hook provides flexibility for handling unknown Ethernet protocols.
+ * 
+ * For example, you can define how to handle packets of unknown types, 
+ * such as forwarding them to another interface, discarding them, 
+ * or passing them to an application for further processing.
+ */
+#define LWIP_HOOK_UNKNOWN_ETH_PROTOCOL lwip_hook_unknown_eth_protocol
+#endif /* RT_LWIP_ENABLE_USER_HOOKS */
+
 #endif /* __LWIPOPTS_H__ */