esp32 wifi promiscuous mode, no control frame captured

[lironghua]

Hi, I'm doing a project to capture WiFi ACK frames under promiscuous mode. These are part of the initialization codes:

Code: Untitled.c Select all

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();

    ESP_ERROR_CHECK(esp_wifi_init(&cfg));



    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA) );

    ESP_ERROR_CHECK(esp_wifi_start());



    ESP_ERROR_CHECK(esp_wifi_set_promiscuous(true)); 

    ESP_ERROR_CHECK(esp_wifi_set_promiscuous_rx_cb(&sniffer)); 

    wifi_promiscuous_filter_t filter = {

          .filter_mask = WIFI_PROMIS_CTRL_FILTER_MASK_ALL|WIFI_PROMIS_FILTER_MASK_DATA|WIFI_PROMIS_FILTER_MASK_CTRL;

    };

    ESP_ERROR_CHECK(esp_wifi_set_promiscuous_filter(&filter));

I've also tried other combinations of filters, but none of them can capture any control frame. Meanwhile, the Management frames and the Data frames can be captured successfully. Does anyone have some ideas?

[lironghua]

Ok, I solved it. It turns out that the ctrl frame filter needs to be set separately via "esp_wifi_set_promiscuous_ctrl_filter"

[roger_]

Can you please post a working filtering example? Is esp_wifi_set_promiscuous_filter() still needed, or just esp_wifi_set_promiscuous_ctrl_filter()?

Thanks!

[lironghua]

Sorry for the late reply. Yes, both are needed. One is for enabling the capture of ctrl packets and the other is for specifying the packet type.

Code: Untitled.c Select all

    ESP_ERROR_CHECK(esp_wifi_set_promiscuous_rx_cb(&sniffer)); 

    wifi_promiscuous_filter_t filter = {

        .filter_mask = WIFI_PROMIS_FILTER_MASK_DATA|WIFI_PROMIS_FILTER_MASK_CTRL

    };

    ESP_ERROR_CHECK(esp_wifi_set_promiscuous_filter(&filter));

    wifi_promiscuous_filter_t ctrl_filter = {

        .filter_mask = WIFI_PROMIS_CTRL_FILTER_MASK_ACK

    };

    ESP_ERROR_CHECK(esp_wifi_set_promiscuous_ctrl_filter(&ctrl_filter));

    esp_wifi_get_promiscuous_filter(&filter);