CSI with packet payload

[ENB213-xiaoh]

Hi All

I'm wondering if it is possible to get the packet payload along with CSI. Because I need the sequence number. I saw some other small projects that did wifi sniffing and get payload, so I want to know if I can combine these two projects. Please kindly advise

[ENB213-xiaoh]

Ok. Never mind. I have made it. Next is replacing one item in the control block to PN.

[StevenMHernandez]

Good idea! What did you change in the code to make it work? It would be really nice to be able to add that feature to the library (as a option for others).

What is PN?

[ENB213-xiaoh]

So, PN is the sequence number. The wifi chipset uses it to count the number of transmitted frames. I think you already know it. It resides in the payload, contains two bytes right after the transmitter and source mac address. So, I basically copied a promiscuous mode callback function from some other sniffer codes.

[StevenMHernandez]

Were you able to write some clean code for the implementation? I don't have time to implement this into the project at this time, but I would be so happy if you could try creating a pull request with this. The feature would very helpful to other users :)

[ENB213-xiaoh]

Okay. My pleasure. I can see your email address. So, I will email you what I have done precisely, maybe tonight or tomorrow. Then, we can discuss it, to see if you are okay with the modification.

[tobiaswer]

Hi, I'm interested in receiving the wifi sequence number along with the CSI as well. Can you share how you were able to obtain it? Thanks!

[ENB213-xiaoh]

include

include "freertos/FreeRTOS.h"

include "freertos/task.h"

include "esp_system.h"

include "esp_spi_flash.h"

include "freertos/event_groups.h"

include "esp_wifi.h"

include "esp_event_loop.h"

include "esp_http_server.h"

include "esp_log.h"

include "nvs_flash.h"

include "math.h"

include "../../_components/nvs_component.h"

include "../../_components/sd_component.h"

include "../../_components/csi_component.h"

include "../../_components/time_component.h"

include "../../_components/input_component.h"

static void extract_macaddr(char addr, uint8_t data, uint16_t offset) { sprintf(addr, "%02X:%02X:%02X:%02X:%02X:%02X", data[offset+0], data[offset+1], data[offset+2], data[offset+3], data[offset+4], data[offset+5]); } // #define LOG_TAG "CSI-DATA"

static void wifi_monitor_cb(void recv_buf, wifi_promiscuous_pkt_type_t type) { if(type != WIFI_PKT_MGMT) return; // Management frames wifi_promiscuous_pkt_t recv_pkt = (wifi_promiscuous_pkt_t *)recv_buf;

// Extract MAC address and print out the result
if (recv_pkt->rx_ctrl.rate == 0) return; // Exclude IEEE802.11b
char addr[] = "00:00:00:00:00:00";
extract_macaddr(addr, recv_pkt->payload, 10);
uint16_t offset = 22;

outprintf("CSI_PN,");
outprintf("%s,", addr);
outprintf("0X%02X%02X,", recv_pkt->payload[offset+0], recv_pkt->payload[offset+1]);
outprintf("%02X%02X", recv_pkt->payload[offset+2], recv_pkt->payload[offset+3]);
outprintf("%02X%02X", recv_pkt->payload[offset+4], recv_pkt->payload[offset+5]);
outprintf("%02X%02X", recv_pkt->payload[offset+6], recv_pkt->payload[offset+7]);
outprintf("%02X%02X", recv_pkt->payload[offset+8], recv_pkt->payload[offset+9]);
outprintf("\n");
sd_flush();
vTaskDelay(0);
// ESP_LOGI(LOG_TAG, "MAC: %s, RSSI: %d, PN: 0x%x%x", addr, recv_pkt->rx_ctrl.rate, recv_pkt->payload[22], recv_pkt->payload[23]);

}

void passive_init() { tcpip_adapter_init(); 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_NULL)); ESP_ERROR_CHECK(esp_wifi_start());

const wifi_promiscuous_filter_t filt = {
        .filter_mask = WIFI_PROMIS_FILTER_MASK_MGMT
};

int curChannel = 3;

ESP_ERROR_CHECK(esp_wifi_set_promiscuous_rx_cb(wifi_monitor_cb));
esp_wifi_set_promiscuous(true);
esp_wifi_set_promiscuous_filter(&filt);
esp_wifi_set_channel(curChannel, WIFI_SECOND_CHAN_NONE);

}

void app_main() { nvs_init(); sd_init(); passive_init(); csi_init("PASSIVE"); input_loop(); }

Hi, tobiaswer. This is the modified main code under passive mode I used to get SN with CSI. I didn't look into the station or AP modes. You will get 2 lines of information for each CSI sequence, one line tagged with "CSI_DATA" is the collected CSI, and another line tagged with "CSI_PN" is the sequence number of the corresponding packet.