From 606363897c1b6f11ba4dd442c80daf00b8fe33ee Mon Sep 17 00:00:00 2001
From: David Cermak <cermak@espressif.com>
Date: Tue, 3 Oct 2023 16:28:30 +0200
Subject: [PATCH] feat(esp_netif): Added new API to search in netif list

---
 components/esp_netif/include/esp_netif.h      | 16 ++++++++
 .../esp_netif/loopback/esp_netif_loopback.c   |  4 +-
 components/esp_netif/lwip/esp_netif_lwip.c    | 28 +++++++++++++
 .../test_app_esp_netif/main/esp_netif_test.c  | 39 +++++++++++++++++++
 4 files changed, 85 insertions(+), 2 deletions(-)

diff --git a/components/esp_netif/include/esp_netif.h b/components/esp_netif/include/esp_netif.h
index a1b3368990..7a698175c4 100644
--- a/components/esp_netif/include/esp_netif.h
+++ b/components/esp_netif/include/esp_netif.h
@@ -985,6 +985,22 @@ 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
  *
diff --git a/components/esp_netif/loopback/esp_netif_loopback.c b/components/esp_netif/loopback/esp_netif_loopback.c
index e3fbb71921..0721fcce58 100644
--- a/components/esp_netif/loopback/esp_netif_loopback.c
+++ b/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);
diff --git a/components/esp_netif/lwip/esp_netif_lwip.c b/components/esp_netif/lwip/esp_netif_lwip.c
index 0d7d7f47c5..0b41dda795 100644
--- a/components/esp_netif/lwip/esp_netif_lwip.c
+++ b/components/esp_netif/lwip/esp_netif_lwip.c
@@ -803,6 +803,34 @@ esp_netif_t *esp_netif_get_handle_from_ifkey(const char *if_key)
     return 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) {
diff --git a/components/esp_netif/test_apps/test_app_esp_netif/main/esp_netif_test.c b/components/esp_netif/test_apps/test_app_esp_netif/main/esp_netif_test.c
index 18b4ee92e5..472a8de7ad 100644
--- a/components/esp_netif/test_apps/test_app_esp_netif/main/esp_netif_test.c
+++ b/components/esp_netif/test_apps/test_app_esp_netif/main/esp_netif_test.c
@@ -129,6 +129,44 @@ 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);
+    }
+}
+
 #ifdef CONFIG_ESP_WIFI_ENABLED
 TEST(esp_netif, dhcp_client_state_transitions_wifi_sta)
 {
@@ -463,6 +501,7 @@ TEST_GROUP_RUNNER(esp_netif)
     RUN_TEST_CASE(esp_netif, convert_ip_addresses)
     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)
 #ifdef CONFIG_ESP_WIFI_ENABLED
     RUN_TEST_CASE(esp_netif, create_custom_wifi_interfaces)
     RUN_TEST_CASE(esp_netif, create_destroy_default_wifi)