Sending arbitrary IEEE 802.11 frames can be useful in various ways, e.g. for mesh networking, unidirectional long-distance communication or low-overhead data transmission. It can, however, be abused for spamming large numbers of invalid SSIDs, jamming WiFi networks or sending deauthentication frames in order to sniff SSIDs of hidden wireless networks. Please be advised that such usage is morally doubtful at best and illegal at worst. Use this at your own risk.

Espressif have now created the esp_wifi_80211_tx API, making esp32free80211 obsolete. The new function is thoroughly documented in the API guide. Since at the time of writing not a lot of sample code using esp_wifi_80211_tx exists and many developers wanting to send arbitrary data with their ESP32s end up using esp32free80211 with an outdated esp-idf version, I want to hereby provide some more up-to-date sample code for esp_wifi_80211_tx.

In order to demonstrate the freedom output functionality, this software broadcasts the infamous lines from Rick Astley's Never gonna give you up. This is achieved by manually assembling IEEE 802.11 beacon frames in main.c and broadcasting them via the currently unofficial esp_wifi_80211_tx API in Espressif's esp32-wifi-lib.

If you want to use raw packet sending functionality in your own project, just declare the esp_wifi_80211_tx function like this:

// buffer: Raw IEEE 802.11 packet to send
// len: Length of IEEE 802.11 packet
// en_sys_seq: see https://github.com/espressif/esp-idf/blob/master/docs/api-guides/wifi.rst#wi-fi-80211-packet-send for details
esp_err_t esp_wifi_80211_tx(wifi_interface_t ifx, const void *buffer, int len, bool en_sys_seq);

This project uses the Espressif IoT Development Framework. With the ESP-IDF installed, execute

make menuconfig

and configure the SDK to use your preferred settings (baudrate, python2 executable, serial flasher port, …) and proceed to compile and flash this project using

make flash

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.