feat(esp_netif): Added new API to search in netif list

components/esp_netif/include/esp_netif.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2019-2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2019-2023 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -945,6 +945,22 @@ int32_t esp_netif_get_event_id(esp_netif_t *esp_netif, esp_netif_ip_event_type_t
  */
 esp_netif_t *esp_netif_next(esp_netif_t *esp_netif);
 
+/**
+ * @brief Predicate callback for esp_netif_find_if() used to find interface
+ *        which meets defined criteria
+ */
+typedef bool (*esp_netif_find_predicate_t)(esp_netif_t *netif, void *ctx);
+
+/**
+ * @brief Return a netif pointer for the interface that meets criteria defined
+ * by the callback
+ *
+ * @param fn Predicate function returning true for the desired interface
+ * @param ctx Context pointer passed to the predicate, typically a descriptor to compare with
+ * @return valid netif pointer if found, NULL if not
+ */
+esp_netif_t *esp_netif_find_if(esp_netif_find_predicate_t fn, void *ctx);
+
 /**
  * @brief Returns number of registered esp_netif objects
  *

components/esp_netif/loopback/esp_netif_loopback.c

@@ -187,7 +187,7 @@ esp_netif_t *esp_netif_new(const esp_netif_config_t *esp_netif_config)
     }
     esp_netif->ip_info_old = ip_info;
 
-    esp_netif_add_to_list(esp_netif);
+    esp_netif_add_to_list_unsafe(esp_netif);
 
     // Configure the created object with provided configuration
     esp_err_t ret =  esp_netif_init_configuration(esp_netif, esp_netif_config);
@@ -203,7 +203,7 @@ esp_netif_t *esp_netif_new(const esp_netif_config_t *esp_netif_config)
 void esp_netif_destroy(esp_netif_t *esp_netif)
 {
     if (esp_netif) {
-        esp_netif_remove_from_list(esp_netif);
+        esp_netif_remove_from_list_unsafe(esp_netif);
         free(esp_netif->ip_info);
         free(esp_netif->ip_info_old);
         free(esp_netif->if_key);

components/esp_netif/lwip/esp_netif_lwip.c

@@ -251,6 +251,16 @@ static inline esp_err_t esp_netif_lwip_ipc_call_fn(esp_netif_api_fn fn, esp_neti
     return esp_netif_lwip_ipc_call_msg(&msg);
 }
 
+static inline esp_err_t esp_netif_lwip_ipc_call_get_netif(esp_netif_api_fn fn, esp_netif_t **netif, void *ctx)
+{
+    esp_netif_api_msg_t msg = {
+            .p_esp_netif = netif,
+            .data = ctx,
+            .api_fn = fn
+    };
+    return esp_netif_lwip_ipc_call_msg(&msg);
+}
+
 static inline esp_err_t esp_netif_lwip_ipc_no_args(esp_netif_api_fn fn)
 {
     esp_netif_api_msg_t msg = {
@@ -768,6 +778,34 @@ esp_netif_t *esp_netif_new(const esp_netif_config_t *esp_netif_config)
     return esp_netif;
 }
 
+typedef struct find_if_api {
+    esp_netif_find_predicate_t fn;
+    void *ctx;
+} find_if_api_t;
+
+static esp_err_t esp_netif_find_if_api(esp_netif_api_msg_t *msg)
+{
+    find_if_api_t *find_if_api = msg->data;
+    esp_netif_t *esp_netif = NULL;
+    while ((esp_netif = esp_netif_next(esp_netif)) != NULL) {
+        if (find_if_api->fn(esp_netif, find_if_api->ctx)) {
+            *msg->p_esp_netif = esp_netif;
+            return ESP_OK;
+        }
+    }
+    return ESP_FAIL;
+}
+
+esp_netif_t *esp_netif_find_if(esp_netif_find_predicate_t fn, void *ctx)
+{
+    esp_netif_t *netif = NULL;
+    find_if_api_t find_if_api = { .fn = fn, .ctx = ctx };
+    if (esp_netif_lwip_ipc_call_get_netif(esp_netif_find_if_api, &netif, &find_if_api) == ESP_OK) {
+        return netif;
+    }
+    return NULL;
+}
+
 static void esp_netif_lwip_remove(esp_netif_t *esp_netif)
 {
     if (esp_netif->lwip_netif) {

components/esp_netif/lwip/esp_netif_lwip_internal.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2015-2023 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -22,9 +22,10 @@ typedef struct esp_netif_api_msg_s {
     int ret;
     esp_netif_api_fn api_fn;
     union {
-        esp_netif_t *esp_netif;
-        esp_netif_callback_fn user_fn;
-    };
+        esp_netif_t *esp_netif;         /* esp_netif as input param */
+        esp_netif_t **p_esp_netif;      /* esp_netif as output */
+        esp_netif_callback_fn user_fn;  /* user callback */
+    };              /* Commonly used parameters what calling api_fn */
     void    *data;
 } esp_netif_api_msg_t;
 

components/esp_netif/test_apps/main/esp_netif_test.c

@@ -77,6 +77,44 @@ TEST(esp_netif, create_delete_multiple_netifs)
 
 }
 
+static bool desc_matches_with(esp_netif_t *netif, void *ctx)
+{
+    return strcmp(ctx, esp_netif_get_desc(netif)) == 0;
+}
+
+TEST(esp_netif, find_netifs)
+{
+    // Create some interfaces
+    const char* if_keys[] = { "if1", "if2", "if3", "if4", "if5"};
+    const int nr_of_netifs = sizeof(if_keys)/sizeof(char*);
+    esp_netif_t *netifs[nr_of_netifs];
+
+    for (int i=0; i<nr_of_netifs; ++i) {
+        // Create all interfaces, the same string is used as a key and as description
+        esp_netif_inherent_config_t base_netif_config = { .if_key = if_keys[i], .if_desc = if_keys[i] };
+        esp_netif_config_t cfg = { .base = &base_netif_config, .stack = ESP_NETIF_NETSTACK_DEFAULT_WIFI_STA };
+        netifs[i] = esp_netif_new(&cfg);
+        TEST_ASSERT_NOT_NULL(netifs[i]);
+    }
+
+    // not found
+    esp_netif_t *found_netif = esp_netif_find_if(desc_matches_with, "not_present");
+    TEST_ASSERT_EQUAL(found_netif, NULL);
+
+    // should find the same netif, as returned from esp_netif_get_handle_from_ifkey(), as the key is the same as description
+    for (int i=0; i<nr_of_netifs; ++i) {
+        found_netif = esp_netif_find_if(desc_matches_with, (void*)if_keys[i]);
+        TEST_ASSERT_EQUAL(found_netif, esp_netif_get_handle_from_ifkey(if_keys[i]));
+    }
+
+    // destroy one by one and check it's cannot be find per its description
+    for (int i=0; i<nr_of_netifs; ++i) {
+        esp_netif_destroy(netifs[i]);
+        found_netif = esp_netif_find_if(desc_matches_with, (void*)if_keys[i]);
+        TEST_ASSERT_EQUAL(found_netif, NULL);
+    }
+}
+
 TEST(esp_netif, dhcp_client_state_transitions_wifi_sta)
 {
     // init default wifi netif
@@ -273,6 +311,7 @@ TEST_GROUP_RUNNER(esp_netif)
     RUN_TEST_CASE(esp_netif, init_and_destroy)
     RUN_TEST_CASE(esp_netif, get_from_if_key)
     RUN_TEST_CASE(esp_netif, create_delete_multiple_netifs)
+    RUN_TEST_CASE(esp_netif, find_netifs)
     RUN_TEST_CASE(esp_netif, dhcp_client_state_transitions_wifi_sta)
     RUN_TEST_CASE(esp_netif, dhcp_server_state_transitions_wifi_ap)
     RUN_TEST_CASE(esp_netif, dhcp_server_state_transitions_mesh)