fix(wifi_remote): Minor fixes per review

components/esp_wifi_remote/eppp/eppp_init.c

@@ -7,7 +7,7 @@
 #include "esp_wifi.h"
 #include "eppp_link.h"
 
-esp_netif_t *wifi_remote_eppp_init(eppp_type_t role)
+__attribute__((weak)) esp_netif_t *wifi_remote_eppp_init(eppp_type_t role)
 {
     uint32_t our_ip = role == EPPP_SERVER ? EPPP_DEFAULT_SERVER_IP() : EPPP_DEFAULT_CLIENT_IP();
     uint32_t their_ip = role == EPPP_SERVER ? EPPP_DEFAULT_CLIENT_IP() : EPPP_DEFAULT_SERVER_IP();

components/esp_wifi_remote/eppp/wifi_remote_rpc_client.cpp

@@ -26,12 +26,15 @@ const char *TAG = "rpc_client";
 const unsigned char ca_crt[] = "-----BEGIN CERTIFICATE-----\n" CONFIG_ESP_WIFI_REMOTE_EPPP_SERVER_CA "\n-----END CERTIFICATE-----";
 const unsigned char crt[] = "-----BEGIN CERTIFICATE-----\n" CONFIG_ESP_WIFI_REMOTE_EPPP_CLIENT_CRT "\n-----END CERTIFICATE-----";
 const unsigned char key[] = "-----BEGIN RSA PRIVATE KEY-----\n" CONFIG_ESP_WIFI_REMOTE_EPPP_CLIENT_KEY "\n-----END RSA PRIVATE KEY-----";
+// TODO: Add option to supply keys and certs via a global symbol (file)
 
 }
 
 using namespace client;
 
-struct Sync {
+class Sync {
+    friend class RpcInstance;
+public:
     void lock()
     {
         xSemaphoreTake(mutex, portMAX_DELAY);
@@ -64,16 +67,21 @@ struct Sync {
             vEventGroupDelete(events);
         }
     }
+
+
+private:
     SemaphoreHandle_t mutex{nullptr};
     EventGroupHandle_t events{nullptr};
+
     const int request = 1;
     const int resp_header = 2;
     const int resp_payload = 4;
-
 };
 
 class RpcInstance {
+    friend class Sync;
 public:
+
     template<typename T>
     esp_err_t send(api_id id, T *t)
     {
@@ -83,7 +91,7 @@ class RpcInstance {
         return ESP_OK;
     }
 
-    // specialization for (void)
+    // overload of the templated method (used for functions with no arguments)
     esp_err_t send(api_id id)
     {
         ESP_RETURN_ON_ERROR(sync.notify(sync.request), TAG, "failed to notify req");
@@ -176,7 +184,7 @@ class RpcInstance {
 
 
 namespace client {
-RpcInstance instance;
+constinit RpcInstance instance;
 }   // namespace client
 
 RpcInstance *RpcEngine::init_client()

components/esp_wifi_remote/eppp/wifi_remote_rpc_impl.hpp

@@ -9,8 +9,11 @@
 
 namespace eppp_rpc {
 
-const int rpc_port = 3333;
+static constexpr int rpc_port = 3333;
 
+/**
+ * @brief Currently supported RPC commands/events
+ */
 enum class api_id : uint32_t {
     ERROR,
     UNDEF,
@@ -35,6 +38,9 @@ struct RpcHeader {
     uint32_t size;
 } __attribute((__packed__));
 
+/**
+ * @brief Structure holding the outgoing or incoming parameter
+ */
 template<typename T>
 struct RpcData {
     RpcHeader head;
@@ -54,11 +60,17 @@ struct RpcData {
     }
 } __attribute((__packed__));
 
+/**
+ * @brief Singleton holding the static data for either the client or server side
+ */
 class RpcInstance;
 
+/**
+ * @brief Engine that implements a simple RPC mechanism
+ */
 class RpcEngine {
 public:
-    explicit RpcEngine(role r) : tls_(nullptr), role_(r) {}
+    constexpr explicit RpcEngine(role r) : tls_(nullptr), role_(r) {}
 
     esp_err_t init()
     {
@@ -90,7 +102,7 @@ class RpcEngine {
         return ESP_OK;
     }
 
-    esp_err_t send(api_id id) // specialization for (void)
+    esp_err_t send(api_id id) // overload for (void)
     {
         RpcHeader head = {.id = id, .size = 0};
         int len = esp_tls_conn_write(tls_, &head, sizeof(head));

components/esp_wifi_remote/eppp/wifi_remote_rpc_server.cpp

@@ -26,6 +26,7 @@ const char *TAG = "rpc_server";
 const unsigned char ca_crt[] = "-----BEGIN CERTIFICATE-----\n" CONFIG_ESP_WIFI_REMOTE_EPPP_CLIENT_CA "\n-----END CERTIFICATE-----";
 const unsigned char crt[] = "-----BEGIN CERTIFICATE-----\n" CONFIG_ESP_WIFI_REMOTE_EPPP_SERVER_CRT "\n-----END CERTIFICATE-----";
 const unsigned char key[] = "-----BEGIN RSA PRIVATE KEY-----\n" CONFIG_ESP_WIFI_REMOTE_EPPP_SERVER_KEY "\n-----END RSA PRIVATE KEY-----";
+// TODO: Add option to supply keys and certs via a global symbol (file)
 
 }
 
@@ -181,7 +182,7 @@ class RpcInstance {
 
 
 namespace server {
-RpcInstance instance;
+constinit RpcInstance instance;
 }
 
 RpcInstance *RpcEngine::init_server()

components/esp_wifi_remote/examples/mqtt/CMakeLists.txt

@@ -1,23 +1,5 @@
 # This project serves as a demo to enable using esp-mqtt on ESP platform targets as well as on linux
 cmake_minimum_required(VERSION 3.16)
 
-if("${IDF_TARGET}" STREQUAL "linux")
-# For linux-target we have two options:
-# - With lwIP (must be defined on command line, e.g. idf.py -DWITH_LWIP=1)
-#     access networking from linux `tap` interface (TAP networking mode)
-# - Without lwIP (must be defined on command line, e.g. idf.py -DWITH_LWIP=0)
-#     no designated interface, accesses user network via linux/socket sys calls
-    if(WITH_LWIP STREQUAL 1)
-        set(EXTRA_COMPONENT_DIRS $ENV{IDF_PATH}/examples/common_components/protocol_examples_tapif_io
-                                 "../../common_components/linux_compat/esp_timer")
-        set(COMPONENTS main esp_netif lwip protocol_examples_tapif_io startup esp_hw_support esp_system nvs_flash mqtt esp_timer)
-    else()
-        list(APPEND EXTRA_COMPONENT_DIRS
-                "../../common_components/linux_compat/esp_timer"
-                "$ENV{IDF_PATH}/examples/protocols/linux_stubs/esp_stubs")
-        set(COMPONENTS main nvs_flash esp-tls esp_stubs mqtt protocol_examples_common esp_timer)
-    endif()
-endif()
-
 include($ENV{IDF_PATH}/tools/cmake/project.cmake)
 project(esp_mqtt_demo)