add support to LWIP_HOOK_UNKNOWN_ETH_PROTOCOL_CALLBACK (IDFGH-4542)

[yanzixiang]

espressif/esp-idf#3526

Wonder If this is the right way,
Maybe useful for someone else.

I use https://github.com/espressif/arduino-esp32 ,
to test this,
replace netif.h and liblwip.a after using esp-idf to complie the example,
esp-idf/examples/ethernet/ethernet.

err_t Callback(struct pbuf *p, struct netif *inp){
  log_e("Callback");
  ESP_LOG_BUFFER_HEX("Callback",p,sizeof(p));
}

register_eth_unknow_type_callback(1,&Callback);

IN

err_t register_eth_unknow_type_callback(u8_t num,netif_input_fn p);

The num is the netif num,
0 for Wifi (Maybe)
1 For Eth (I Use this)

[liuzfesp]

Thanks @yanzixiang for your contribution.

My suggestion is to put the hook implementation into the port directory. E.g.

• Put HOOKS.h to $IDF_PATH/components/lwip/port/esp32/include/netif
• Add HOOKS.c to $IDF_PATH/components/lwip/port/esp32/netif/HOOKS.c and put eth_unknow_type_callback(), register_eth_unknow_type_callback()
  ...

We need to minimize ESP-specific modifications in LWIP submodule.

[yanzixiang]

Thanks @yanzixiang for your contribution.

My suggestion is to put the hook implementation into the port directory. E.g.

• Put HOOKS.h to $IDF_PATH/components/lwip/port/esp32/include/netif
• Add HOOKS.c to $IDF_PATH/components/lwip/port/esp32/netif/HOOKS.c and put eth_unknow_type_callback(), register_eth_unknow_type_callback()
  ...

We need to minimize ESP-specific modifications in LWIP submodule.

So I shold gen a Pull Request at esp-idf instead of esp-lwip ?

[david-cermak]

@yanzixiang I agree with @liuzfesp that the hooks shall be defined in specific port layer.
Now (in IDF v4.3), we have good a place in IDF, where we could put default lwip hooks:
https://github.com/espressif/esp-idf/blob/master/components/lwip/port/esp32/include/lwip_default_hooks.h

Closing this, as the hooks don't really fit into esp-lwip repository. Please don't hesitate to post a PR to IDF repository!