Add WiFi Easy Connect (DPP) wrappers and associated example

jasta · jasta · commit c156ba906dea · 2023-02-14T17:32:10.000-08:00
diff --git a/Cargo.toml b/Cargo.toml
@@ -30,8 +30,8 @@ log = { version = "0.4", default-features = false }
 uncased = "0.9.7"
 anyhow = { version = "1", default-features = false, optional = true } # Only used by the deprecated httpd module
 embedded-svc = { version = "0.24", default-features = false }
-esp-idf-sys = { version = "0.32.1", default-features = false, features = ["native"] }
-esp-idf-hal = { version = "0.40", default-features = false, features = ["esp-idf-sys"] }
+esp-idf-sys = { path = "/home/jasta/software/esp-idf-sys", default-features = false, features = ["native"] }
+esp-idf-hal = { path = "/home/jasta/software/esp-idf-hal", default-features = false, features = ["esp-idf-sys"] }
 embassy-sync = { version = "0.1", optional = true }
 embassy-time = { version = "0.1", optional = true, features = ["tick-hz-1_000_000"] }
 
diff --git a/examples/wifi_dpp_setup.rs b/examples/wifi_dpp_setup.rs
@@ -0,0 +1,76 @@
+//! Example using Wi-Fi Easy Connect (DPP) to get a device onto a Wi-Fi network
+//! without hardcoding credentials.
+
+extern crate core;
+
+use esp_idf_hal as _;
+
+use std::time::Duration;
+use embedded_svc::wifi::{ClientConfiguration, Configuration, Wifi};
+use esp_idf_hal::peripherals::Peripherals;
+use esp_idf_svc::eventloop::EspSystemEventLoop;
+use esp_idf_svc::log::EspLogger;
+use esp_idf_svc::nvs::EspDefaultNvsPartition;
+use esp_idf_svc::wifi::{EspWifi, WifiWait};
+use esp_idf_sys::EspError;
+use log::{error, info, LevelFilter, warn};
+use esp_idf_svc::wifi_dpp::EspDppBootstrapper;
+
+fn main() -> anyhow::Result<()> {
+    esp_idf_sys::link_patches();
+
+    EspLogger::initialize_default();
+
+    let peripherals = Peripherals::take().unwrap();
+    let sysloop = EspSystemEventLoop::take()?;
+    let nvs = EspDefaultNvsPartition::take()?;
+
+    let mut wifi = EspWifi::new(peripherals.modem, sysloop.clone(), Some(nvs))?;
+
+    if !wifi_has_sta_config(&wifi)? {
+        info!("No existing STA config, let's try DPP...");
+        let config = dpp_listen_forever(&mut wifi)?;
+        info!("Got config: {config:?}");
+        wifi.set_configuration(&Configuration::Client(config))?;
+    }
+
+    wifi.start()?;
+
+    let timeout = Duration::from_secs(60);
+    loop {
+        let ssid = match wifi.get_configuration()? {
+            Configuration::None => None,
+            Configuration::Client(ap) => Some(ap.ssid),
+            Configuration::AccessPoint(_) => None,
+            Configuration::Mixed(_, _) => None,
+        }.unwrap();
+        info!("Connecting to {ssid}...");
+        wifi.connect()?;
+        let waiter = WifiWait::new(&sysloop)?;
+        let is_connected = waiter.wait_with_timeout(timeout, || wifi.is_connected().unwrap());
+        if is_connected {
+            info!("Connected!");
+            waiter.wait(|| !wifi.is_connected().unwrap());
+            warn!("Got disconnected, connecting again...");
+        } else {
+            error!("Failed to connect after {}s, trying again...", timeout.as_secs());
+        }
+    }
+}
+
+fn wifi_has_sta_config(wifi: &EspWifi) -> Result<bool, EspError> {
+    match wifi.get_configuration()? {
+        Configuration::Client(c) => Ok(!c.ssid.is_empty()),
+        _ => Ok(false),
+    }
+}
+
+fn dpp_listen_forever(wifi: &mut EspWifi) -> Result<ClientConfiguration, EspError> {
+    let mut dpp = EspDppBootstrapper::new(wifi)?;
+    let channels: Vec<_> = (1..=11).collect();
+    let bootstrapped = dpp.gen_qrcode(&channels, None, None)?;
+    println!("Got: {}", bootstrapped.data.0);
+    println!("(use a QR code generator and scan the code in the Wi-Fi setup flow on your phone)");
+
+    bootstrapped.listen_forever()
+}
diff --git a/src/lib.rs b/src/lib.rs
@@ -25,6 +25,14 @@
 #[macro_use]
 extern crate alloc;
 
+#[cfg(all(
+    feature = "alloc",
+    esp_idf_comp_wpa_supplicant_enabled,
+    any(
+        esp_idf_esp_wifi_dpp_support,
+        esp_idf_wpa_dpp_support
+    )))]
+pub mod wifi_dpp;
 pub mod errors;
 #[cfg(all(
     feature = "alloc",
diff --git a/src/wifi_dpp.rs b/src/wifi_dpp.rs
@@ -0,0 +1,223 @@
+//! Wi-Fi Easy Connect (DPP) support
+//!
+//! To use this feature, you must add CONFIG_WPA_DPP_SUPPORT=y to your sdkconfig.
+
+use ::log::*;
+
+use std::ffi::{c_char, CStr, CString};
+use std::fmt::Write;
+use std::ops::Deref;
+use std::ptr;
+use std::sync::mpsc::{Receiver, sync_channel, SyncSender};
+use embedded_svc::wifi::{ClientConfiguration, Configuration, Wifi};
+use esp_idf_sys::*;
+use esp_idf_sys::EspError;
+use crate::private::common::Newtype;
+use crate::private::mutex;
+use crate::wifi::EspWifi;
+
+static EVENTS_TX: mutex::Mutex<Option<SyncSender<DppEvent>>> =
+    mutex::Mutex::wrap(mutex::RawMutex::new(), None);
+
+pub struct EspDppBootstrapper<'d, 'w> {
+    wifi: &'d mut EspWifi<'w>,
+    events_rx: Receiver<DppEvent>,
+}
+
+impl<'d, 'w> EspDppBootstrapper<'d, 'w> {
+    pub fn new(wifi: &'d mut EspWifi<'w>) -> Result<Self, EspError> {
+        if wifi.is_started()? {
+            wifi.disconnect()?;
+            wifi.stop()?;
+        }
+
+        Self::init(wifi)
+    }
+
+    fn init(wifi: &'d mut EspWifi<'w>) -> Result<Self, EspError> {
+        let (events_tx, events_rx) = sync_channel(1);
+        let mut dpp_event_relay = EVENTS_TX.lock();
+        *dpp_event_relay = Some(events_tx);
+        drop(dpp_event_relay);
+        esp!(unsafe { esp_supp_dpp_init(Some(Self::dpp_event_cb_unsafe)) })?;
+        Ok(Self {
+            wifi,
+            events_rx,
+        })
+    }
+
+    /// Generate a QR code that can be scanned by a mobile phone or other configurator
+    /// to securely provide us with the Wi-Fi credentials.  Must invoke a listen API on the returned
+    /// bootstrapped instance (e.g. [EspDppBootstrapped::listen_once]) or scanning the
+    /// QR code will not be able to deliver the credentials to us.
+    ///
+    /// Important implementation notes:
+    ///
+    /// 1. You must provide _all_ viable channels that the AP could be using
+    /// in order to successfully acquire credentials!  For example, in the US, you can use
+    /// `(1..=11).collect()`.
+    ///
+    /// 2. The WiFi driver will be forced started and with a default STA config unless the
+    /// state is set-up ahead of time.  It's unclear if the AuthMethod that you select
+    /// for this STA config affects the results.
+    pub fn gen_qrcode<'b>(
+        &'b mut self,
+        channels: &[u8],
+        key: Option<&[u8; 32]>,
+        associated_data: Option<&[u8]>
+    ) -> Result<EspDppBootstrapped<'b, QrCode>, EspError> {
+        let mut channels_str = channels.into_iter()
+            .fold(String::new(), |mut a, c| {
+                write!(a, "{c},").unwrap();
+                a
+            });
+        channels_str.pop();
+        let channels_cstr = CString::new(channels_str).unwrap();
+        let key_ascii_cstr = key.map(|k| {
+            let result = k.iter()
+                .fold(String::new(), |mut a, b| {
+                    write!(a, "{b:02X}").unwrap();
+                    a
+                });
+            CString::new(result).unwrap()
+        });
+        let associated_data_cstr = match associated_data {
+            Some(associated_data) => {
+                Some(CString::new(associated_data)
+                    .map_err(|_| {
+                        warn!("associated data contains an embedded NUL character!");
+                        EspError::from_infallible::<ESP_ERR_INVALID_ARG>()
+                    })?)
+            }
+            None => None,
+        };
+        debug!("dpp_bootstrap_gen...");
+        esp!(unsafe {
+      esp_supp_dpp_bootstrap_gen(
+          channels_cstr.as_ptr(),
+          dpp_bootstrap_type_DPP_BOOTSTRAP_QR_CODE,
+          key_ascii_cstr.map_or_else(ptr::null, |x| x.as_ptr()),
+          associated_data_cstr.map_or_else(ptr::null, |x| x.as_ptr()))
+    })?;
+        let event = self.events_rx.recv()
+            .map_err(|_| {
+                warn!("Internal error receiving event!");
+                EspError::from_infallible::<ESP_ERR_INVALID_STATE>()
+            })?;
+        debug!("dpp_bootstrap_gen got: {event:?}");
+        match event {
+            DppEvent::UriReady(qrcode) => {
+                // Bit of a hack to put the wifi driver in the correct mode.
+                self.ensure_config_and_start()?;
+                Ok(EspDppBootstrapped::<QrCode> {
+                    events_rx: &self.events_rx,
+                    data: QrCode(qrcode),
+                })
+            }
+            _ => {
+                warn!("Got unexpected event: {event:?}");
+                Err(EspError::from_infallible::<ESP_ERR_INVALID_STATE>())
+            },
+        }
+    }
+
+    fn ensure_config_and_start(&mut self) -> Result<ClientConfiguration, EspError> {
+        let operating_config = match self.wifi.get_configuration()? {
+            Configuration::Client(c) => c,
+            _ => {
+                let fallback_config = ClientConfiguration::default();
+                self.wifi.set_configuration(&Configuration::Client(fallback_config.clone()))?;
+                fallback_config
+            },
+        };
+        if !self.wifi.is_started()? {
+            self.wifi.start()?;
+        }
+        Ok(operating_config)
+    }
+
+    unsafe extern "C" fn dpp_event_cb_unsafe(
+        evt: esp_supp_dpp_event_t,
+        data: *mut ::core::ffi::c_void
+    ) {
+        debug!("dpp_event_cb_unsafe: evt={evt}");
+        let event = match evt {
+            esp_supp_dpp_event_t_ESP_SUPP_DPP_URI_READY => {
+                DppEvent::UriReady(CStr::from_ptr(data as *mut c_char).to_str().unwrap().into())
+            },
+            esp_supp_dpp_event_t_ESP_SUPP_DPP_CFG_RECVD => {
+                let config = data as *mut wifi_config_t;
+                // TODO: We're losing pmf_cfg.required=true setting due to missing
+                // information in ClientConfiguration.
+                DppEvent::ConfigurationReceived(Newtype((*config).sta).into())
+            },
+            esp_supp_dpp_event_t_ESP_SUPP_DPP_FAIL => {
+                DppEvent::Fail(EspError::from(data as esp_err_t).unwrap())
+            }
+            _ => panic!(),
+        };
+        dpp_event_cb(event)
+    }
+}
+
+fn dpp_event_cb(event: DppEvent) {
+    match EVENTS_TX.lock().deref() {
+        Some(tx) => {
+            debug!("Sending: {event:?}");
+            if let Err(e) = tx.try_send(event) {
+                error!("Cannot relay event: {e}");
+            }
+        }
+        None => warn!("Got spurious {event:?} ???"),
+    }
+}
+
+
+#[derive(Debug)]
+enum DppEvent {
+    UriReady(String),
+    ConfigurationReceived(ClientConfiguration),
+    Fail(EspError),
+}
+
+impl<'d, 'w> Drop for EspDppBootstrapper<'d, 'w> {
+    fn drop(&mut self) {
+        unsafe { esp_supp_dpp_deinit() };
+    }
+}
+
+pub struct EspDppBootstrapped<'d, T> {
+    events_rx: &'d Receiver<DppEvent>,
+    pub data: T,
+}
+
+#[derive(Debug, Clone)]
+pub struct QrCode(pub String);
+
+impl<'d, T> EspDppBootstrapped<'d, T> {
+    pub fn listen_once(&self) -> Result<ClientConfiguration, EspError> {
+        esp!(unsafe { esp_supp_dpp_start_listen() })?;
+        let event = self.events_rx.recv()
+            .map_err(|e| {
+                warn!("Internal receive error: {e}");
+                EspError::from_infallible::<ESP_ERR_INVALID_STATE>()
+            })?;
+        match event {
+            DppEvent::ConfigurationReceived(config) => Ok(config),
+            DppEvent::Fail(e) => Err(e),
+            _ => {
+                warn!("Ignoring unexpected event {event:?}");
+                Err(EspError::from_infallible::<ESP_ERR_INVALID_STATE>())
+            }
+        }
+    }
+
+    pub fn listen_forever(&self) -> Result<ClientConfiguration, EspError> {
+        loop {
+            match self.listen_once() {
+                Ok(config) => return Ok(config),
+                Err(e) => warn!("DPP error: {e}, trying again..."),
+            }
+        }
+    }
+}
