ESP8266 Community Forum

- Wed Feb 11, 2015 8:58 pm #9522 So in the SDK documentation I see there is support for promiscuous mode, receiving raw wifi packets. However I don't see that Espressif has created any function to send a raw wifi packet in the docs. If we could inject packets the ESP8266 could easily send smart config, not just receive it, for example. Does anyone know how to send raw wifi packets using the ESP8266 or if this is going to be added anytime soon in the SDK? BTW in case you're interested here's an implementation of using promiscuous to get MAC addresses nearby:

Code: Select all#include "ets_sys.h"
#include "osapi.h"
#include "gpio.h"
#include "os_type.h"
#include "user_config.h"
#include "user_interface.h"
#include "driver/uart.h"

#define user_procTaskPrio        0
#define user_procTaskQueueLen    1
#define CHANNEL_HOP_INTERVAL 200
os_event_t    user_procTaskQueue[user_procTaskQueueLen];
static volatile os_timer_t channelHop_timer;

static void loop(os_event_t *events);
static void promisc_cb(uint8 *buf, uint16 len);

void printmac(char* buf, unsigned int o)
{
   if(buf[o+4] == 0x00 && buf[o+5] == 0x00)
      return;
   if(buf[o+4] == 0xff && buf[o+5] == 0xff)
      return;
   int i;
   for(i=0;i<6;i++)
      if(buf[o+i] != 0x00 && buf[o+i] != 0xff)
         goto good;
   return;
   good: ;
   char mac[strlen("00:00:00:00:00:00\n")];
   os_sprintf(mac, "%02x:%02x:%02x:%02x:%02x:%02x\n", buf[o+0], buf[o+1], buf[o+2], buf[o+3], buf[o+4], buf[o+5]);
   uart0_sendStr(mac);
}

void channelHop(void *arg)
{
    // 1 - 13 channel hopping
    uint8 new_channel = wifi_get_channel() % 12 + 1;
    os_printf("** hop to %d **\n", new_channel);
    wifi_set_channel(new_channel);
}

static void ICACHE_FLASH_ATTR
promisc_cb(uint8 *buf, uint16 len)
{
   os_printf("-> %3d: %d", wifi_get_channel(), len);
    printmac(buf,  4);
    printmac(buf, 10);
    printmac(buf, 16);

    os_printf("\n");
}

//Main code function
static void ICACHE_FLASH_ATTR
loop(os_event_t *events)
{

    os_delay_us(10);
}

//Init function
void ICACHE_FLASH_ATTR
user_init()
{
    uart_init(115200, 115200);
    os_delay_us(100);

    uart0_sendStr("*** Monitor mode test ***\r\n");
   
    os_printf(" -> Promisc mode setup ... ");
    wifi_set_promiscuous_rx_cb(promisc_cb);
    wifi_promiscuous_enable(1);
    os_printf("done.\n");

    os_printf(" -> Timer setup ... ");
    os_timer_disarm(&channelHop_timer);
    os_timer_setfn(&channelHop_timer, (os_timer_func_t *) channelHop, NULL);
    os_timer_arm(&channelHop_timer, CHANNEL_HOP_INTERVAL, 1);
    os_printf("done.\n");
   
    os_printf(" -> Set opmode ... ");
    wifi_set_opmode( 0x1 );
    os_printf("done.\n");

    //Start os task
    system_os_task(loop, user_procTaskPrio,user_procTaskQueue, user_procTaskQueueLen);

    os_printf(" -> Init finished!\n\n");
}


- Wed Feb 25, 2015 1:59 pm #10711 >>So in the SDK documentation I see there is support for promiscuous mode, receiving raw wifi packets.
Not really. Get the package completely impossible, since the buffer is limited to 128 bytes.
Increase the buffer developers are not going to be wondering where the reception packet buffer and its length ...

- Mon Jun 22, 2015 1:36 pm #21256 Sorry to gravedig, but any progress in this department?
I'm working on an application where I don't want to deal with a lot of wifi issues like AP disassociation, ACKs, etc..
The data must be streamed continuously and whatever packets make it will be used. This is realtime data, so there is no need to re-transmit bad packets since fresh data will likely be available.

- Tue Feb 02, 2016 12:19 am #40227 The newer SDK has a new function called `wifi_send_pkt_freedom` which lets you send raw packets.

It seems to restrict which frame types you can send.
Any data (type 2) frame is allowed.
Only beacon management frames are allowed (type 0, subtype 8).
No control frames (type 1).