gavinb-esp/raw-esp

Raw IP/Ethernet-forwarding firmware for ESP8266 WiFi module

Main repo located at https://gitlab.com/goodwin-europe/raw-esp

Raw IP / Ethernet packet firmware for ESP8266 WiFi module

It's sometimes desirable to bypass ESP's TCP/IP stack and use network stack of a host microcontroller instead.

This firmware presents ESP8266 to the host as IP- or Ethernet-layer link with additional functions to configure WiFi, logging, etc. All communication with ESP8266 is done via binary message-based protocol over RS232.

In IP-forwarding mode ESP8266 firmware internally runs ARP and, optionally, DHCP. Non-DHCP UDP packets and TCP packets are forwarded to the host. Packets received from host are injected into ESP's network stack. ICMP packets aren't currently forwarded (because I haven't bothered, that's easy to fix). Both AP/STA modes are supported. Network may be configured with DHCP or statically. This mode works with ESP SDK <1.1.1. On version >=1.1.1 it tends to hang after the first injected packed, though I haven't tested with versions >=1.4.

In Ethernet-forwarding mode ESP's LwIP stack is completely detached. Its timers are operational and it attemps to send something from time to time, but those packets are dropped. All packets coming from WiFi interface are redirected to the host, and packets coming from host are passed directly to ESP's WiFi interface.

Compilation & flashing

1. Install toolchain
2. Clone this repo: git clone --recurse-submodules https://gitlab.com/goodwin-europe/raw-esp
3. Run make: make. Firmware will be placed in firmware/.
4. Flash your esp8266 with esptool. Following command is suitable for versions with 4MB flash. For other sizes see answer at stackoverflow esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect 0 0x00000.bin 0x10000 0x10000.bin 0x3fc000 esp_sdk/bin/esp_init_data_default_v08.bin

Host interface

Host interface is documented in user_main/message.h.