Merge pull request #8418 from tannewt/fix_mdns_crash_after_user_disconnect

Fix MDNS after the user turns off wifi

Author: dhalbert

ports/espressif/common-hal/mdns/Server.c

@@ -36,16 +36,22 @@
 // Track whether the underlying IDF mdns has been started so that we only
 // create a single inited MDNS object to CircuitPython. (After deinit, another
 // could be created.)
-STATIC bool mdns_started = false;
+STATIC mdns_server_obj_t *_active_object = NULL;
 
 void mdns_server_construct(mdns_server_obj_t *self, bool workflow) {
-    if (mdns_started) {
+    if (_active_object != NULL) {
+        if (self == _active_object) {
+            return;
+        }
         // Mark this object as deinited because another is already using MDNS.
         self->inited = false;
         return;
     }
-    mdns_init();
-    mdns_started = true;
+    esp_err_t ret = mdns_init();
+    if (ret != ESP_OK) {
+        return;
+    }
+    _active_object = self;
 
     uint8_t mac[6];
     esp_netif_get_mac(common_hal_wifi_radio_obj.netif, mac);
@@ -86,10 +92,16 @@ void common_hal_mdns_server_deinit(mdns_server_obj_t *self) {
         return;
     }
     self->inited = false;
-    mdns_started = false;
+    _active_object = NULL;
     mdns_free();
 }
 
+void mdns_server_deinit_singleton(void) {
+    if (_active_object != NULL) {
+        common_hal_mdns_server_deinit(_active_object);
+    }
+}
+
 bool common_hal_mdns_server_deinited(mdns_server_obj_t *self) {
     return !self->inited;
 }

ports/espressif/common-hal/mdns/Server.h

@@ -36,3 +36,5 @@ typedef struct {
     // Track if this object owns access to the underlying MDNS service.
     bool inited;
 } mdns_server_obj_t;
+
+void mdns_server_deinit_singleton(void);

ports/espressif/common-hal/wifi/Radio.c

@@ -44,7 +44,7 @@
 #include "components/lwip/include/apps/ping/ping_sock.h"
 
 #if CIRCUITPY_MDNS
-#include "components/mdns/include/mdns.h"
+#include "common-hal/mdns/Server.h"
 #endif
 
 #define MAC_ADDRESS_LENGTH 6
@@ -97,7 +97,7 @@ void common_hal_wifi_radio_set_enabled(wifi_radio_obj_t *self, bool enabled) {
             common_hal_wifi_radio_stop_scanning_networks(self);
         }
         #if CIRCUITPY_MDNS
-        mdns_free();
+        mdns_server_deinit_singleton();
         #endif
         ESP_ERROR_CHECK(esp_wifi_stop());
         self->started = false;