Add support for passive WiFi scanning (#4666)

* Add support for passive WiFi scanning.

* Apply suggestions from code review

Made changes suggested by @jesserockz

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

---------

Co-authored-by: BellaCoola <unknown>
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/components/wifi/__init__.py

@@ -252,6 +252,7 @@ def _validate(config):
 
 
 CONF_OUTPUT_POWER = "output_power"
+CONF_PASSIVE_SCAN = "passive_scan"
 CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
@@ -280,6 +281,7 @@ def _validate(config):
             cv.SplitDefault(CONF_ENABLE_RRM, esp32_idf=False): cv.All(
                 cv.boolean, cv.only_with_esp_idf
             ),
+            cv.Optional(CONF_PASSIVE_SCAN, default=False): cv.boolean,
             cv.Optional("enable_mdns"): cv.invalid(
                 "This option has been removed. Please use the [disabled] option under the "
                 "new mdns component instead."
@@ -379,6 +381,7 @@ def add_sta(ap, network):
     cg.add(var.set_reboot_timeout(config[CONF_REBOOT_TIMEOUT]))
     cg.add(var.set_power_save_mode(config[CONF_POWER_SAVE_MODE]))
     cg.add(var.set_fast_connect(config[CONF_FAST_CONNECT]))
+    cg.add(var.set_passive_scan(config[CONF_PASSIVE_SCAN]))
     if CONF_OUTPUT_POWER in config:
         cg.add(var.set_output_power(config[CONF_OUTPUT_POWER]))
 

esphome/components/wifi/wifi_component.cpp

@@ -385,7 +385,7 @@ void WiFiComponent::print_connect_params_() {
 void WiFiComponent::start_scanning() {
   this->action_started_ = millis();
   ESP_LOGD(TAG, "Starting scan...");
-  this->wifi_scan_start_();
+  this->wifi_scan_start_(this->passive_scan_);
   this->state_ = WIFI_COMPONENT_STATE_STA_SCANNING;
 }
 
@@ -615,6 +615,8 @@ bool WiFiComponent::is_connected() {
 }
 void WiFiComponent::set_power_save_mode(WiFiPowerSaveMode power_save) { this->power_save_ = power_save; }
 
+void WiFiComponent::set_passive_scan(bool passive) { this->passive_scan_ = passive; }
+
 std::string WiFiComponent::format_mac_addr(const uint8_t *mac) {
   char buf[20];
   sprintf(buf, "%02X:%02X:%02X:%02X:%02X:%02X", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);

esphome/components/wifi/wifi_component.h

@@ -217,6 +217,8 @@ class WiFiComponent : public Component {
   void set_power_save_mode(WiFiPowerSaveMode power_save);
   void set_output_power(float output_power) { output_power_ = output_power; }
 
+  void set_passive_scan(bool passive);
+
   void save_wifi_sta(const std::string &ssid, const std::string &password);
   // ========== INTERNAL METHODS ==========
   // (In most use cases you won't need these)
@@ -294,7 +296,7 @@ class WiFiComponent : public Component {
   bool wifi_sta_connect_(const WiFiAP &ap);
   void wifi_pre_setup_();
   WiFiSTAConnectStatus wifi_sta_connect_status_();
-  bool wifi_scan_start_();
+  bool wifi_scan_start_(bool passive);
   bool wifi_ap_ip_config_(optional<ManualIP> manual_ip);
   bool wifi_start_ap_(const WiFiAP &ap);
   bool wifi_disconnect_();
@@ -349,6 +351,7 @@ class WiFiComponent : public Component {
   bool scan_done_{false};
   bool ap_setup_{false};
   optional<float> output_power_;
+  bool passive_scan_{false};
   ESPPreferenceObject pref_;
   bool has_saved_wifi_settings_{false};
 #ifdef USE_WIFI_11KV_SUPPORT

esphome/components/wifi/wifi_component_esp32_arduino.cpp

@@ -618,13 +618,13 @@ WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() {
   }
   return WiFiSTAConnectStatus::IDLE;
 }
-bool WiFiComponent::wifi_scan_start_() {
+bool WiFiComponent::wifi_scan_start_(bool passive) {
   // enable STA
   if (!this->wifi_mode_(true, {}))
     return false;
 
   // need to use WiFi because of WiFiScanClass allocations :(
-  int16_t err = WiFi.scanNetworks(true, true, false, 200);
+  int16_t err = WiFi.scanNetworks(true, true, passive, 200);
   if (err != WIFI_SCAN_RUNNING) {
     ESP_LOGV(TAG, "WiFi.scanNetworks failed! %d", err);
     return false;

esphome/components/wifi/wifi_component_esp8266.cpp

@@ -601,7 +601,7 @@ WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() {
       return WiFiSTAConnectStatus::IDLE;
   }
 }
-bool WiFiComponent::wifi_scan_start_() {
+bool WiFiComponent::wifi_scan_start_(bool passive) {
   static bool first_scan = false;
 
   // enable STA
@@ -615,13 +615,21 @@ bool WiFiComponent::wifi_scan_start_() {
   config.channel = 0;
   config.show_hidden = 1;
 #if USE_ARDUINO_VERSION_CODE >= VERSION_CODE(2, 4, 0)
-  config.scan_type = WIFI_SCAN_TYPE_ACTIVE;
+  config.scan_type = passive ? WIFI_SCAN_TYPE_PASSIVE : WIFI_SCAN_TYPE_ACTIVE;
   if (first_scan) {
-    config.scan_time.active.min = 100;
-    config.scan_time.active.max = 200;
+    if (passive) {
+      config.scan_time.passive = 200;
+    } else {
+      config.scan_time.active.min = 100;
+      config.scan_time.active.max = 200;
+    }
   } else {
-    config.scan_time.active.min = 400;
-    config.scan_time.active.max = 500;
+    if (passive) {
+      config.scan_time.passive = 500;
+    } else {
+      config.scan_time.active.min = 400;
+      config.scan_time.active.max = 500;
+    }
   }
 #endif
   first_scan = false;

esphome/components/wifi/wifi_component_esp_idf.cpp

@@ -736,7 +736,7 @@ WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() {
   }
   return WiFiSTAConnectStatus::IDLE;
 }
-bool WiFiComponent::wifi_scan_start_() {
+bool WiFiComponent::wifi_scan_start_(bool passive) {
   // enable STA
   if (!this->wifi_mode_(true, {}))
     return false;
@@ -746,9 +746,13 @@ bool WiFiComponent::wifi_scan_start_() {
   config.bssid = nullptr;
   config.channel = 0;
   config.show_hidden = true;
-  config.scan_type = WIFI_SCAN_TYPE_ACTIVE;
-  config.scan_time.active.min = 100;
-  config.scan_time.active.max = 300;
+  config.scan_type = passive ? WIFI_SCAN_TYPE_PASSIVE : WIFI_SCAN_TYPE_ACTIVE;
+  if (passive) {
+    config.scan_time.passive = 300;
+  } else {
+    config.scan_time.active.min = 100;
+    config.scan_time.active.max = 300;
+  }
 
   esp_err_t err = esp_wifi_scan_start(&config, false);
   if (err != ESP_OK) {

esphome/components/wifi/wifi_component_pico_w.cpp

@@ -125,10 +125,11 @@ void WiFiComponent::wifi_scan_result(void *env, const cyw43_ev_scan_result_t *re
   }
 }
 
-bool WiFiComponent::wifi_scan_start_() {
+bool WiFiComponent::wifi_scan_start_(bool passive) {
   this->scan_result_.clear();
   this->scan_done_ = false;
   cyw43_wifi_scan_options_t scan_options = {0};
+  scan_options.scan_type = passive ? 1 : 0;
   int err = cyw43_wifi_scan(&cyw43_state, &scan_options, nullptr, &s_wifi_scan_result);
   if (err) {
     ESP_LOGV(TAG, "cyw43_wifi_scan failed!");