esp-hal/examples/src/bin/wifi_embassy_access_point.rs

//! Embassy access point
//!
//! - creates an open access-point with SSID `esp-wifi`
//! - you can connect to it using a static IP in range 192.168.2.2 .. 192.168.2.255, gateway 192.168.2.1
//! - open http://192.168.2.1:8080/ in your browser - the example will perform an HTTP get request to some "random" server
//!
//! On Android you might need to choose _Keep Accesspoint_ when it tells you the WiFi has no internet connection, Chrome might not want to load the URL - you can use a shell and try `curl` and `ping`
//!
//! Because of the huge task-arena size configured this won't work on ESP32-S2

//% FEATURES: embassy embassy-generic-timers esp-wifi esp-wifi/async esp-wifi/embassy-net esp-wifi/wifi-default esp-wifi/wifi esp-wifi/utils
//% CHIPS: esp32 esp32s2 esp32s3 esp32c2 esp32c3 esp32c6

#![no_std]
#![no_main]

use embassy_executor::Spawner;
use embassy_net::{
    tcp::TcpSocket,
    IpListenEndpoint,
    Ipv4Address,
    Ipv4Cidr,
    Stack,
    StackResources,
    StaticConfigV4,
};
use embassy_time::{Duration, Timer};
use esp_alloc as _;
use esp_backtrace as _;
use esp_hal::{prelude::*, rng::Rng, timer::timg::TimerGroup};
use esp_println::{print, println};
use esp_wifi::{
    initialize,
    wifi::{
        AccessPointConfiguration,
        Configuration,
        WifiApDevice,
        WifiController,
        WifiDevice,
        WifiEvent,
        WifiState,
    },
    EspWifiInitFor,
};

// When you are okay with using a nightly compiler it's better to use https://docs.rs/static_cell/2.1.0/static_cell/macro.make_static.html
macro_rules! mk_static {
    ($t:ty,$val:expr) => {{
        static STATIC_CELL: static_cell::StaticCell<$t> = static_cell::StaticCell::new();
        #[deny(unused_attributes)]
        let x = STATIC_CELL.uninit().write(($val));
        x
    }};
}

#[esp_hal_embassy::main]
async fn main(spawner: Spawner) -> ! {
    esp_println::logger::init_logger_from_env();
    let peripherals = esp_hal::init({
        let mut config = esp_hal::Config::default();
        config.cpu_clock = CpuClock::max();
        config
    });

    esp_alloc::heap_allocator!(72 * 1024);

    let timg0 = TimerGroup::new(peripherals.TIMG0);

    let init = initialize(
        EspWifiInitFor::Wifi,
        timg0.timer0,
        Rng::new(peripherals.RNG),
        peripherals.RADIO_CLK,
    )
    .unwrap();

    let wifi = peripherals.WIFI;
    let (wifi_interface, controller) =
        esp_wifi::wifi::new_with_mode(&init, wifi, WifiApDevice).unwrap();

    cfg_if::cfg_if! {
        if #[cfg(feature = "esp32")] {
            let timg1 = TimerGroup::new(peripherals.TIMG1);
            esp_hal_embassy::init(timg1.timer0);
        } else {
            use esp_hal::timer::systimer::{SystemTimer, Target};
            let systimer = SystemTimer::new(peripherals.SYSTIMER).split::<Target>();
            esp_hal_embassy::init(systimer.alarm0);
        }
    }

    let config = embassy_net::Config::ipv4_static(StaticConfigV4 {
        address: Ipv4Cidr::new(Ipv4Address::new(192, 168, 2, 1), 24),
        gateway: Some(Ipv4Address::from_bytes(&[192, 168, 2, 1])),
        dns_servers: Default::default(),
    });

    let seed = 1234; // very random, very secure seed

    // Init network stack
    let stack = &*mk_static!(
        Stack<WifiDevice<'_, WifiApDevice>>,
        Stack::new(
            wifi_interface,
            config,
            mk_static!(StackResources<3>, StackResources::<3>::new()),
            seed
        )
    );

    spawner.spawn(connection(controller)).ok();
    spawner.spawn(net_task(&stack)).ok();

    let mut rx_buffer = [0; 1536];
    let mut tx_buffer = [0; 1536];

    loop {
        if stack.is_link_up() {
            break;
        }
        Timer::after(Duration::from_millis(500)).await;
    }
    println!("Connect to the AP `esp-wifi` and point your browser to http://192.168.2.1:8080/");
    println!("Use a static IP in the range 192.168.2.2 .. 192.168.2.255, use gateway 192.168.2.1");

    let mut socket = TcpSocket::new(&stack, &mut rx_buffer, &mut tx_buffer);
    socket.set_timeout(Some(embassy_time::Duration::from_secs(10)));
    loop {
        println!("Wait for connection...");
        let r = socket
            .accept(IpListenEndpoint {
                addr: None,
                port: 8080,
            })
            .await;
        println!("Connected...");

        if let Err(e) = r {
            println!("connect error: {:?}", e);
            continue;
        }

        use embedded_io_async::Write;

        let mut buffer = [0u8; 1024];
        let mut pos = 0;
        loop {
            match socket.read(&mut buffer).await {
                Ok(0) => {
                    println!("read EOF");
                    break;
                }
                Ok(len) => {
                    let to_print =
                        unsafe { core::str::from_utf8_unchecked(&buffer[..(pos + len)]) };

                    if to_print.contains("\r\n\r\n") {
                        print!("{}", to_print);
                        println!();
                        break;
                    }

                    pos += len;
                }
                Err(e) => {
                    println!("read error: {:?}", e);
                    break;
                }
            };
        }

        let r = socket
            .write_all(
                b"HTTP/1.0 200 OK\r\n\r\n\
            <html>\
                <body>\
                    <h1>Hello Rust! Hello esp-wifi!</h1>\
                </body>\
            </html>\r\n\
            ",
            )
            .await;
        if let Err(e) = r {
            println!("write error: {:?}", e);
        }

        let r = socket.flush().await;
        if let Err(e) = r {
            println!("flush error: {:?}", e);
        }
        Timer::after(Duration::from_millis(1000)).await;

        socket.close();
        Timer::after(Duration::from_millis(1000)).await;

        socket.abort();
    }
}

#[embassy_executor::task]
async fn connection(mut controller: WifiController<'static>) {
    println!("start connection task");
    println!("Device capabilities: {:?}", controller.get_capabilities());
    loop {
        match esp_wifi::wifi::get_wifi_state() {
            WifiState::ApStarted => {
                // wait until we're no longer connected
                controller.wait_for_event(WifiEvent::ApStop).await;
                Timer::after(Duration::from_millis(5000)).await
            }
            _ => {}
        }
        if !matches!(controller.is_started(), Ok(true)) {
            let client_config = Configuration::AccessPoint(AccessPointConfiguration {
                ssid: "esp-wifi".try_into().unwrap(),
                ..Default::default()
            });
            controller.set_configuration(&client_config).unwrap();
            println!("Starting wifi");
            controller.start().await.unwrap();
            println!("Wifi started!");
        }
    }
}

#[embassy_executor::task]
async fn net_task(stack: &'static Stack<WifiDevice<'static, WifiApDevice>>) {
    stack.run().await
}