Merge pull request #710 from david-cermak/feat/mosq_p2p_example

[mosq]: Add serverless broker example

.github/workflows/clang-tidy.yml

@@ -24,6 +24,7 @@ jobs:
           chmod +x clang-tidy-sarif
           curl -sSL https://raw.githubusercontent.com/espressif/idf-extra-components/master/.github/filter_sarif.py -o filter_sarif.py
       - name: Install pyclang
+        shell: bash
         run: |
           . ${IDF_PATH}/export.sh
           pip install pyclang~=0.2.0

.github/workflows/modem__target-test.yml

@@ -80,7 +80,12 @@ jobs:
           name: modem_target_bin_${{ matrix.idf_target }}_${{ matrix.idf_ver }}_${{ matrix.test.app }}
           path: ${{ env.TEST_DIR }}/build
       - name: Run Example Test on target
-        working-directory: ${{ env.TEST_DIR }}
+        env:
+          PIP_EXTRA_INDEX_URL: "https://dl.espressif.com/pypi/"
         run: |
-            python -m pip install -r $GITHUB_WORKSPACE/ci/requirements.txt
+            python -m venv .venv
+            source .venv/bin/activate
+            pip install --prefer-binary cryptography pytest-embedded pytest-embedded-serial-esp pytest-embedded-idf pytest-custom_exit_code esptool
+            pip install -r $GITHUB_WORKSPACE/ci/requirements.txt
+            cd ${{ env.TEST_DIR }}
             python -m pytest --log-cli-level DEBUG --target=${{ matrix.idf_target }}

.github/workflows/mosq__build.yml

@@ -17,7 +17,8 @@ jobs:
     runs-on: ubuntu-22.04
     container: espressif/idf:${{ matrix.idf_ver }}
     env:
-      TEST_DIR: components/mosquitto/examples/broker
+      TEST_DIR: components/mosquitto/examples
+      TARGET_TEST: broker
       TARGET_TEST_DIR: build_esp32_default
     steps:
       - name: Checkout esp-protocols
@@ -29,14 +30,15 @@ jobs:
         run: |
           . ${IDF_PATH}/export.sh
           pip install idf-component-manager idf-build-apps --upgrade
-          python ci/build_apps.py ${TEST_DIR}
-          cd ${TEST_DIR}
+          python ci/build_apps.py -c ${TEST_DIR} -m components/mosquitto/.build-test-rules.yml
+          # upload only the target test artifacts
+          cd ${TEST_DIR}/${TARGET_TEST}
           ${GITHUB_WORKSPACE}/ci/clean_build_artifacts.sh `pwd`/${TARGET_TEST_DIR}
           zip -qur artifacts.zip ${TARGET_TEST_DIR}
       - uses: actions/upload-artifact@v4
         with:
           name: mosq_target_esp32_${{ matrix.idf_ver }}
-          path: ${{ env.TEST_DIR }}/artifacts.zip
+          path: ${{ env.TEST_DIR }}/${{ env.TARGET_TEST }}/artifacts.zip
           if-no-files-found: error
 
   test_mosq:

ci/check_copyright_ignore.txt

@@ -0,0 +1 @@
+components/mosquitto/examples/serverless_mqtt/components/libjuice/port/juice_random.c

components/esp_modem/.cz.yaml

@@ -3,6 +3,6 @@ commitizen:
   bump_message: 'bump(modem): $current_version -> $new_version'
   pre_bump_hooks: python ../../ci/changelog.py esp_modem
   tag_format: modem-v$version
-  version: 1.2.1
+  version: 1.3.0
   version_files:
   - idf_component.yml

components/esp_modem/CHANGELOG.md

@@ -1,5 +1,21 @@
 # Changelog
 
+## [1.3.0](https://github.com/espressif/esp-protocols/commits/modem-v1.3.0)
+
+### Features
+
+- Add mode detection to the example ([18f196fa](https://github.com/espressif/esp-protocols/commit/18f196fa))
+- Support for pausing network in C-API ([1db83cd1](https://github.com/espressif/esp-protocols/commit/1db83cd1))
+- Add support for pausing netif ([247f1681](https://github.com/espressif/esp-protocols/commit/247f1681), [#699](https://github.com/espressif/esp-protocols/issues/699))
+
+### Bug Fixes
+
+- Minor cleanup of pppos example ([5e929902](https://github.com/espressif/esp-protocols/commit/5e929902))
+- Fix PPP mode detection to accept LCP/conf ([c989c6ad](https://github.com/espressif/esp-protocols/commit/c989c6ad))
+- Refine mode switch data->command ([8b6ea331](https://github.com/espressif/esp-protocols/commit/8b6ea331), [#692](https://github.com/espressif/esp-protocols/issues/692))
+- Detect serial ports properly ([0cb59ff8](https://github.com/espressif/esp-protocols/commit/0cb59ff8))
+- Fix CMUX enter to ignore URC before transition ([1284f66d](https://github.com/espressif/esp-protocols/commit/1284f66d), [#669](https://github.com/espressif/esp-protocols/issues/669))
+
 ## [1.2.1](https://github.com/espressif/esp-protocols/commits/modem-v1.2.1)
 
 ### Bug Fixes

components/esp_modem/Kconfig

@@ -76,4 +76,20 @@ menu "esp-modem"
         help
             If enabled, APIs to add URC handler are available
 
+    config ESP_MODEM_PPP_ESCAPE_BEFORE_EXIT
+        bool "Send escape sequence when switching PPP -> CMD"
+        default n
+        help
+            If enabled, the library sends a PPP escape ("+++" command)
+            to switch to command mode. This make switching from PPP to CMD
+            mode more robust for some devices (e.g. Quectel), but might cause
+            trouble for other devices (e.g. SIMCOM).
+
+    config ESP_MODEM_ADD_DEBUG_LOGS
+        bool "Add UART Tx/Rx logs"
+        default n
+        help
+            If enabled, the library dumps all transmitted and received data.
+            This option is only used for debugging.
+
 endmenu

components/esp_modem/examples/modem_console/main/modem_console_main.cpp

@@ -385,6 +385,17 @@ extern "C" void app_main(void)
         return 0;
     });
 #endif
+    const ConsoleCommand PauseNetwork("pause_net", "toggle network pause", no_args, [&](ConsoleCommand * c) {
+        static int cnt = 0;
+        if (++cnt % 2) {
+            ESP_LOGI(TAG, "Pausing netif");
+            dce->pause_netif(true);
+        } else {
+            ESP_LOGI(TAG, "Unpausing netif");
+            dce->pause_netif(false);
+        }
+        return 0;
+    });
 
     const struct SetApn {
         SetApn(): apn(STR1, nullptr, nullptr, "<apn>", "APN (Access Point Name)") {}

components/esp_modem/examples/pppos_client/main/Kconfig.projbuild

@@ -201,4 +201,23 @@ menu "Example Configuration"
         help
             MQTT data message, which we publish and expect to receive.
 
+    config EXAMPLE_PAUSE_NETIF_TO_CHECK_SIGNAL
+        bool "Demonstrate netif pause"
+        default n
+        help
+            Set this to true to demonstrate network pausing.
+            If enabled, the example waits for an MQTT data, then temporarily
+            drops network to check signal quality, resumes networking and
+            publishes another MQTT message.
+            Connection to the MQTT broker should be kept.
+
+    config EXAMPLE_DETECT_MODE_BEFORE_CONNECT
+        bool "Detect mode before connect"
+        default n
+        help
+            Set this to true to demonstrate mode auto-detection.
+            If enabled, the example tries to recognize the actual mode.
+            If mode is detected correctly and it is not a command mode,
+            then the example switches to command mode.
+
 endmenu

components/esp_modem/examples/pppos_client/main/pppos_client_main.c

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2022-2024 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Unlicense OR CC0-1.0
  */
@@ -34,6 +34,7 @@
 static const char *TAG = "pppos_example";
 static EventGroupHandle_t event_group = NULL;
 static const int CONNECT_BIT = BIT0;
+static const int DISCONNECT_BIT = BIT1;
 static const int GOT_DATA_BIT = BIT2;
 static const int USB_DISCONNECTED_BIT = BIT3; // Used only with USB DTE but we define it unconditionally, to avoid too many #ifdefs in the code
 
@@ -55,6 +56,7 @@ static void usb_terminal_error_handler(esp_modem_terminal_error_t err)
 }
 #define CHECK_USB_DISCONNECTION(event_group) \
 if ((xEventGroupGetBits(event_group) & USB_DISCONNECTED_BIT) == USB_DISCONNECTED_BIT) { \
+    ESP_LOGE(TAG, "USB_DISCONNECTED_BIT destroying modem dce");                                            \
     esp_modem_destroy(dce); \
     continue; \
 }
@@ -140,6 +142,7 @@ static void on_ip_event(void *arg, esp_event_base_t event_base,
         ESP_LOGI(TAG, "GOT ip event!!!");
     } else if (event_id == IP_EVENT_PPP_LOST_IP) {
         ESP_LOGI(TAG, "Modem Disconnect from PPP Server");
+        xEventGroupSetBits(event_group, DISCONNECT_BIT);
     } else if (event_id == IP_EVENT_GOT_IP6) {
         ESP_LOGI(TAG, "GOT IPv6 event!");
 
@@ -158,6 +161,7 @@ void app_main(void)
     ESP_ERROR_CHECK(esp_event_handler_register(NETIF_PPP_STATUS, ESP_EVENT_ANY_ID, &on_ppp_changed, NULL));
 
     /* Configure the PPP netif */
+    esp_err_t err;
     esp_modem_dce_config_t dce_config = ESP_MODEM_DCE_DEFAULT_CONFIG(CONFIG_EXAMPLE_MODEM_PPP_APN);
     esp_netif_config_t netif_ppp_config = ESP_NETIF_DEFAULT_PPP();
     esp_netif_t *esp_netif = esp_netif_new(&netif_ppp_config);
@@ -205,7 +209,7 @@ void app_main(void)
 #endif
     assert(dce);
     if (dte_config.uart_config.flow_control == ESP_MODEM_FLOW_CONTROL_HW) {
-        esp_err_t err = esp_modem_set_flow_control(dce, 2, 2);  //2/2 means HW Flow Control.
+        err = esp_modem_set_flow_control(dce, 2, 2);  //2/2 means HW Flow Control.
         if (err != ESP_OK) {
             ESP_LOGE(TAG, "Failed to set the set_flow_control mode");
             return;
@@ -246,7 +250,27 @@ void app_main(void)
 #error Invalid serial connection to modem.
 #endif
 
-    xEventGroupClearBits(event_group, CONNECT_BIT | GOT_DATA_BIT | USB_DISCONNECTED_BIT);
+#if CONFIG_EXAMPLE_DETECT_MODE_BEFORE_CONNECT
+    xEventGroupClearBits(event_group, CONNECT_BIT | GOT_DATA_BIT | USB_DISCONNECTED_BIT | DISCONNECT_BIT);
+
+    err = esp_modem_set_mode(dce, ESP_MODEM_MODE_DETECT);
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "esp_modem_set_mode(ESP_MODEM_MODE_DETECT) failed with %d", err);
+        return;
+    }
+    esp_modem_dce_mode_t mode = esp_modem_get_mode(dce);
+    ESP_LOGI(TAG, "Mode detection completed: current mode is: %d", mode);
+    if (mode == ESP_MODEM_MODE_DATA) {  // set back to command mode
+        err = esp_modem_set_mode(dce, ESP_MODEM_MODE_COMMAND);
+        if (err != ESP_OK) {
+            ESP_LOGE(TAG, "esp_modem_set_mode(ESP_MODEM_MODE_COMMAND) failed with %d", err);
+            return;
+        }
+        ESP_LOGI(TAG, "Command mode restored");
+    }
+#endif // CONFIG_EXAMPLE_DETECT_MODE_BEFORE_CONNECT
+
+    xEventGroupClearBits(event_group, CONNECT_BIT | GOT_DATA_BIT | USB_DISCONNECTED_BIT | DISCONNECT_BIT);
 
     /* Run the modem demo app */
 #if CONFIG_EXAMPLE_NEED_SIM_PIN == 1
@@ -262,7 +286,7 @@ void app_main(void)
 #endif
 
     int rssi, ber;
-    esp_err_t err = esp_modem_get_signal_quality(dce, &rssi, &ber);
+    err = esp_modem_get_signal_quality(dce, &rssi, &ber);
     if (err != ESP_OK) {
         ESP_LOGE(TAG, "esp_modem_get_signal_quality failed with %d %s", err, esp_err_to_name(err));
         return;
@@ -301,22 +325,41 @@ void app_main(void)
     }
     /* Wait for IP address */
     ESP_LOGI(TAG, "Waiting for IP address");
-    xEventGroupWaitBits(event_group, CONNECT_BIT | USB_DISCONNECTED_BIT, pdFALSE, pdFALSE, portMAX_DELAY);
+    xEventGroupWaitBits(event_group, CONNECT_BIT | USB_DISCONNECTED_BIT | DISCONNECT_BIT, pdFALSE, pdFALSE,
+                        pdMS_TO_TICKS(60000));
     CHECK_USB_DISCONNECTION(event_group);
+    if ((xEventGroupGetBits(event_group) & CONNECT_BIT) != CONNECT_BIT) {
+        ESP_LOGW(TAG, "Modem not connected, switching back to the command mode");
+        err = esp_modem_set_mode(dce, ESP_MODEM_MODE_COMMAND);
+        if (err != ESP_OK) {
+            ESP_LOGE(TAG, "esp_modem_set_mode(ESP_MODEM_MODE_COMMAND) failed with %d", err);
+            return;
+        }
+        ESP_LOGI(TAG, "Command mode restored");
+        return;
+    }
 
     /* Config MQTT */
-#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 0, 0)
     esp_mqtt_client_config_t mqtt_config = {
         .broker.address.uri = CONFIG_EXAMPLE_MQTT_BROKER_URI,
     };
-#else
-    esp_mqtt_client_config_t mqtt_config = {
-        .uri = CONFIG_EXAMPLE_MQTT_BROKER_URI,
-    };
-#endif
     esp_mqtt_client_handle_t mqtt_client = esp_mqtt_client_init(&mqtt_config);
     esp_mqtt_client_register_event(mqtt_client, ESP_EVENT_ANY_ID, mqtt_event_handler, NULL);
     esp_mqtt_client_start(mqtt_client);
+
+#if CONFIG_EXAMPLE_PAUSE_NETIF_TO_CHECK_SIGNAL
+    xEventGroupWaitBits(event_group, GOT_DATA_BIT, pdTRUE, pdFALSE, portMAX_DELAY);
+    esp_modem_pause_net(dce, true);
+    err = esp_modem_get_signal_quality(dce, &rssi, &ber);
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "esp_modem_get_signal_quality failed with %d", err);
+        return;
+    }
+    ESP_LOGI(TAG, "Signal quality: rssi=%d, ber=%d", rssi, ber);
+    esp_modem_pause_net(dce, false);
+    esp_mqtt_client_publish(mqtt_client, CONFIG_EXAMPLE_MQTT_TEST_TOPIC, CONFIG_EXAMPLE_MQTT_TEST_DATA, 0, 0, 0);
+#endif // CONFIG_EXAMPLE_PAUSE_NETIF_TO_CHECK_SIGNAL
+
     ESP_LOGI(TAG, "Waiting for MQTT data");
     xEventGroupWaitBits(event_group, GOT_DATA_BIT | USB_DISCONNECTED_BIT, pdFALSE, pdFALSE, portMAX_DELAY);
     CHECK_USB_DISCONNECTION(event_group);

components/esp_modem/examples/pppos_client/pytest_pppos_client.py

@@ -12,7 +12,7 @@ def test_pppos_connect(dut):
       4. checks that the client cleanly disconnects
     """
     # Check the sequence of connecting, publishing, disconnecting
-    dut.expect('Modem Connect to PPP Server')
+    dut.expect('Modem Connect to PPP Server', timeout=90)
     # Check for MQTT connection and the data event
     dut.expect('MQTT_EVENT_CONNECTED')
     dut.expect('MQTT_EVENT_DATA')

components/esp_modem/examples/pppos_client/sdkconfig.ci.sim800_c3

@@ -11,5 +11,7 @@ CONFIG_EXAMPLE_MODEM_DEVICE_SIM800=y
 CONFIG_EXAMPLE_MODEM_DEVICE_BG96=n
 CONFIG_EXAMPLE_MODEM_PPP_APN="lpwa.vodafone.com"
 CONFIG_EXAMPLE_MQTT_TEST_TOPIC="/ci/esp-modem/pppos-client"
+CONFIG_EXAMPLE_PAUSE_NETIF_TO_CHECK_SIGNAL=y
 CONFIG_ESP_SYSTEM_PANIC_PRINT_HALT=y
 CONFIG_ESP32_PANIC_PRINT_HALT=y
+CONFIG_EXAMPLE_DETECT_MODE_BEFORE_CONNECT=y

components/esp_modem/examples/simple_cmux_client/sdkconfig.ci.sim800_cmux

@@ -16,3 +16,4 @@ CONFIG_COMPILER_CXX_EXCEPTIONS=y
 CONFIG_ESP_MAIN_TASK_STACK_SIZE=8192
 CONFIG_EXAMPLE_CLOSE_CMUX_AT_END=y
 CONFIG_EXAMPLE_MQTT_TEST_TOPIC="/ci/esp-modem/pppos-client"
+CONFIG_BROKER_URI="mqtt://mqtt.eclipseprojects.io"

components/esp_modem/idf_component.yml

@@ -1,4 +1,4 @@
-version: "1.2.1"
+version: "1.3.0"
 description: Library for communicating with cellular modems in command and data modes
 url: https://github.com/espressif/esp-protocols/tree/master/components/esp_modem
 issues: https://github.com/espressif/esp-protocols/issues

components/esp_modem/include/cxx_include/esp_modem_dce.hpp

@@ -91,6 +91,11 @@ public:
         return mode.set(dte.get(), device.get(), netif, m);
     }
 
+    modem_mode get_mode()
+    {
+        return mode.get();
+    }
+
     bool recover()
     {
         return dte->recover();
@@ -103,6 +108,29 @@ public:
     }
 #endif
 
+    /**
+     * @brief Pauses/Unpauses network temporarily
+     * @param do_pause true to pause, false to unpause
+     * @param force true to ignore command failures and continue
+     * @return command_result of the underlying commands
+     */
+    command_result pause_netif(bool do_pause, bool force = false, int delay = 1000)
+    {
+        command_result result;
+        if (do_pause) {
+            netif.pause();
+            Task::Delay(delay); // Mandatory 1s pause before
+            dte->set_command_callbacks();
+            result = device->set_command_mode();
+        } else {
+            result = device->resume_data_mode();
+            if (result == command_result::OK || force) {
+                netif.resume();
+            }
+        }
+        return result;
+    }
+
 protected:
     std::shared_ptr<DTE> dte;
     std::shared_ptr<SpecificModule> device;

components/esp_modem/include/cxx_include/esp_modem_dce_module.hpp

@@ -77,7 +77,9 @@ public:
                 if (set_command_mode() == command_result::OK) {
                     return true;
                 }
-                Task::Delay(1000); // Mandatory 1s pause after escape
+                // send a newline to delimit the escape from the upcoming sync command
+                uint8_t delim = '\n';
+                dte->write(&delim, 1);
                 if (sync() == command_result::OK) {
                     return true;
                 }

components/esp_modem/include/cxx_include/esp_modem_dte.hpp

@@ -145,6 +145,12 @@ public:
      */
     bool recover();
 
+    /**
+     * @brief Set internal command callbacks to the underlying terminal.
+     * Here we capture command replies to be processed by supplied command callbacks in  struct command_cb.
+     */
+    void set_command_callbacks();
+
 protected:
     /**
      * @brief Allows for locking the DTE
@@ -204,12 +210,6 @@ private:
     } inflatable;
 #endif // CONFIG_ESP_MODEM_USE_INFLATABLE_BUFFER_IF_NEEDED
 
-    /**
-     * @brief Set internal command callbacks to the underlying terminal.
-     * Here we capture command replies to be processed by supplied command callbacks in  struct command_cb.
-     */
-    void set_command_callbacks();
-
     /**
      * @brief This abstracts command callback processing and implements its locking, signaling of completion and timeouts.
      */

components/esp_modem/include/cxx_include/esp_modem_netif.hpp

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2021-2024 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -54,6 +54,16 @@ public:
      */
     void stop();
 
+    /**
+     * @brief Pause the network interface
+     */
+    void pause();
+
+    /**
+     * @brief Resume the network interface
+     */
+    void resume();
+
     void receive(uint8_t *data, size_t len);
 
 private:

components/esp_modem/include/esp_modem_c_api_types.h

@@ -45,6 +45,8 @@ typedef enum esp_modem_dce_mode {
     ESP_MODEM_MODE_CMUX_MANUAL_SWAP,    /**< Swap terminals in CMUX manual mode */
     ESP_MODEM_MODE_CMUX_MANUAL_DATA,    /**< Set DATA mode in CMUX manual mode */
     ESP_MODEM_MODE_CMUX_MANUAL_COMMAND, /**< Set COMMAND mode in CMUX manual mode */
+    ESP_MODEM_MODE_DETECT,              /**< Detect the mode and resume it (if sucessfully detected) */
+    ESP_MODEM_MODE_UNDEF,
 } esp_modem_dce_mode_t;
 
 /**
@@ -160,6 +162,18 @@ esp_err_t esp_modem_set_apn(esp_modem_dce_t *dce, const char *apn);
 esp_err_t esp_modem_set_urc(esp_modem_dce_t *dce, esp_err_t(*got_line_cb)(uint8_t *data, size_t len));
 #endif
 
+/**
+ * @brief This API provides support for temporarily pausing networking in order
+ * to send/receive AT commands and resume networking afterwards.
+ * @note This function does not switch modes, the modem is still in data mode.
+ *
+ * @param dce Modem DCE handle
+ * @param pause true to pause the network interface, false to resume networking
+ * @return ESP_OK on success
+ */
+esp_err_t esp_modem_pause_net(esp_modem_dce_t *dce, bool pause);
+
+esp_modem_dce_mode_t esp_modem_get_mode(esp_modem_dce_t *dce);
 /**
  * @}
  */

components/esp_modem/src/esp_modem_c_api.cpp

@@ -95,12 +95,43 @@ extern "C" esp_err_t esp_modem_sync(esp_modem_dce_t *dce_wrap)
     return command_response_to_esp_err(dce_wrap->dce->sync());
 }
 
+extern "C" esp_modem_dce_mode_t esp_modem_get_mode(esp_modem_dce_t *dce_wrap)
+{
+    if (dce_wrap == nullptr || dce_wrap->dce == nullptr) {
+        return ESP_MODEM_MODE_UNDEF;
+    }
+    auto mode = dce_wrap->dce->get_mode();
+    switch (mode) {
+    default:
+    case modem_mode::UNDEF:
+        return ESP_MODEM_MODE_UNDEF;
+    case modem_mode::COMMAND_MODE:
+        return ESP_MODEM_MODE_COMMAND;
+    case modem_mode::DATA_MODE:
+        return ESP_MODEM_MODE_DATA;
+    case modem_mode::CMUX_MODE:
+        return ESP_MODEM_MODE_CMUX;
+    case modem_mode::CMUX_MANUAL_MODE:
+        return ESP_MODEM_MODE_CMUX_MANUAL;
+    case modem_mode::CMUX_MANUAL_EXIT:
+        return ESP_MODEM_MODE_CMUX_MANUAL_EXIT;
+    case modem_mode::CMUX_MANUAL_DATA:
+        return ESP_MODEM_MODE_CMUX_MANUAL_DATA;
+    case modem_mode::CMUX_MANUAL_COMMAND:
+        return ESP_MODEM_MODE_CMUX_MANUAL_COMMAND;
+    case modem_mode::CMUX_MANUAL_SWAP:
+        return ESP_MODEM_MODE_CMUX_MANUAL_SWAP;
+    }
+}
+
 extern "C" esp_err_t esp_modem_set_mode(esp_modem_dce_t *dce_wrap, esp_modem_dce_mode_t mode)
 {
     if (dce_wrap == nullptr || dce_wrap->dce == nullptr) {
         return ESP_ERR_INVALID_ARG;
     }
     switch (mode) {
+    case ESP_MODEM_MODE_UNDEF:
+        return dce_wrap->dce->set_mode(modem_mode::UNDEF) ? ESP_OK : ESP_FAIL;
     case ESP_MODEM_MODE_DATA:
         return dce_wrap->dce->set_mode(modem_mode::DATA_MODE) ? ESP_OK : ESP_FAIL;
     case ESP_MODEM_MODE_COMMAND:
@@ -117,6 +148,8 @@ extern "C" esp_err_t esp_modem_set_mode(esp_modem_dce_t *dce_wrap, esp_modem_dce
         return dce_wrap->dce->set_mode(modem_mode::CMUX_MANUAL_DATA) ? ESP_OK : ESP_FAIL;
     case ESP_MODEM_MODE_CMUX_MANUAL_COMMAND:
         return dce_wrap->dce->set_mode(modem_mode::CMUX_MANUAL_COMMAND) ? ESP_OK : ESP_FAIL;
+    case ESP_MODEM_MODE_DETECT:
+        return dce_wrap->dce->set_mode(modem_mode::AUTODETECT) ? ESP_OK : ESP_FAIL;
     }
     return ESP_ERR_NOT_SUPPORTED;
 }
@@ -475,3 +508,19 @@ extern "C" esp_err_t esp_modem_set_urc(esp_modem_dce_t *dce_wrap, esp_err_t(*got
     return ESP_OK;
 }
 #endif
+
+extern "C" esp_err_t esp_modem_pause_net(esp_modem_dce_t *dce_wrap, bool pause)
+{
+    if (dce_wrap == nullptr || dce_wrap->dce == nullptr) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    return command_response_to_esp_err(dce_wrap->dce->pause_netif(pause));
+}
+
+extern "C" esp_err_t esp_modem_hang_up(esp_modem_dce_t *dce_wrap)
+{
+    if (dce_wrap == nullptr || dce_wrap->dce == nullptr) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    return command_response_to_esp_err(dce_wrap->dce->hang_up());
+}

components/esp_modem/src/esp_modem_cmux.cpp

@@ -123,7 +123,12 @@ bool CMux::data_available(uint8_t *data, size_t len)
 {
     if (data && (type & FT_UIH) == FT_UIH && len > 0 && dlci > 0) { // valid payload on a virtual term
         int virtual_term = dlci - 1;
-        if (virtual_term < MAX_TERMINALS_NUM && read_cb[virtual_term]) {
+        if (virtual_term < MAX_TERMINALS_NUM) {
+            if (read_cb[virtual_term] == nullptr) {
+                // ignore all virtual terminal's data before we completely establish CMUX
+                ESP_LOG_BUFFER_HEXDUMP("CMUX Rx before init", data, len, ESP_LOG_DEBUG);
+                return true;
+            }
             // Post partial data (or defragment to post on CMUX footer)
 #ifdef DEFRAGMENT_CMUX_PAYLOAD
             if (payload_start == nullptr) {
@@ -142,7 +147,11 @@ bool CMux::data_available(uint8_t *data, size_t len)
         sabm_ack = dlci;
     } else if (data == nullptr && dlci > 0) {
         int virtual_term = dlci - 1;
-        if (virtual_term < MAX_TERMINALS_NUM && read_cb[virtual_term]) {
+        if (virtual_term < MAX_TERMINALS_NUM) {
+            if (read_cb[virtual_term] == nullptr) {
+                // silently ignore this CMUX frame (not finished entering CMUX, yet)
+                return true;
+            }
 #ifdef DEFRAGMENT_CMUX_PAYLOAD
             read_cb[virtual_term](payload_start, total_payload_size);
 #endif

components/esp_modem/src/esp_modem_dce.cpp

@@ -18,7 +18,6 @@ namespace transitions {
 
 static bool exit_data(DTE &dte, ModuleIf &device, Netif &netif)
 {
-    netif.stop();
     auto signal = std::make_shared<SignalGroup>();
     std::weak_ptr<SignalGroup> weak_signal = signal;
     dte.set_read_cb([&netif, weak_signal](uint8_t *data, size_t len) -> bool {
@@ -32,7 +31,7 @@ static bool exit_data(DTE &dte, ModuleIf &device, Netif &netif)
         if (memchr(data, '\n', len))
         {
             ESP_LOG_BUFFER_HEXDUMP("esp-modem: debug_data (CMD)", data, len, ESP_LOG_DEBUG);
-            const auto pass = std::list<std::string_view>({"NO CARRIER", "DISCONNECTED"});
+            const auto pass = std::list<std::string_view>({"NO CARRIER", "DISCONNECTED", "OK"});
             std::string_view response((char *) data, len);
             for (auto &it : pass)
                 if (response.find(it) != std::string::npos) {
@@ -44,8 +43,14 @@ static bool exit_data(DTE &dte, ModuleIf &device, Netif &netif)
         }
         return false;
     });
+    netif.stop();
     netif.wait_until_ppp_exits();
-    if (!signal->wait(1, 2000)) {
+#ifdef ESP_MODEM_PPP_ESCAPE_BEFORE_EXIT
+    std::array<uint8_t, 3> ppp_escape = {'+', '+', '+'};
+    dte.write(ppp_escape.data(), ppp_escape.size());
+#endif
+    if (!signal->wait(1, 2000)) { // wait for any of the disconnection messages
+        // if no reply -> set device to command mode
         dte.set_read_cb(nullptr);
         if (!device.set_mode(modem_mode::COMMAND_MODE)) {
             return false;
@@ -323,12 +328,19 @@ modem_mode DCE_Mode::guess_unsafe(DTE *dte, bool with_cmux)
         if (reply_pos >= sizeof(probe::ppp::lcp_echo_reply_head)) {
             // check for initial 2 bytes
             auto *ptr = static_cast<uint8_t *>(memmem(reply, reply_pos, probe::ppp::lcp_echo_reply_head.data(), 2));
-            // and check the other two bytes for protocol ID: LCP
+            // and check the other two bytes for protocol ID:
+            // * either LCP reply
             if (ptr && ptr[3] == probe::ppp::lcp_echo_reply_head[3] && ptr[4] == probe::ppp::lcp_echo_reply_head[4]) {
                 if (auto signal = weak_signal.lock()) {
                     signal->set(probe::ppp::mode);
                 }
             }
+            // * or LCP conf request
+            if (ptr && ptr[3] == probe::ppp::lcp_echo_request[3] && ptr[4] == probe::ppp::lcp_echo_request[4]) {
+                if (auto signal = weak_signal.lock()) {
+                    signal->set(probe::ppp::mode);
+                }
+            }
         }
         if (reply_pos >= 4 && memmem(reply, reply_pos, probe::cmd::reply, sizeof(probe::cmd::reply))) {
             if (reply[0] != 0xf9) {   // double check that the reply is not wrapped in CMUX headers

components/esp_modem/src/esp_modem_netif.cpp

@@ -99,6 +99,20 @@ void Netif::stop()
     signal.clear(PPP_STARTED);
 }
 
+void Netif::resume()
+{
+    ppp_dte->set_read_cb([this](uint8_t *data, size_t len) -> bool {
+        receive(data, len);
+        return true;
+    });
+    signal.set(PPP_STARTED);
+}
+
+void Netif::pause()
+{
+    signal.clear(PPP_STARTED);
+}
+
 Netif::~Netif()
 {
     if (signal.is_any(PPP_STARTED)) {

components/esp_modem/src/esp_modem_netif_linux.cpp

@@ -52,7 +52,6 @@ void Netif::start()
 
 void Netif::stop()
 {
-    ppp_dte->set_read_cb(nullptr);
     signal.clear(PPP_STARTED);
 }
 

components/esp_modem/src/esp_modem_uart.cpp

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2021-2024 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -176,13 +176,20 @@ int UartTerminal::read(uint8_t *data, size_t len)
     uart_get_buffered_data_len(uart.port, &length);
     length = std::min(len, length);
     if (length > 0) {
-        return uart_read_bytes(uart.port, data, length, portMAX_DELAY);
+        int read_len = uart_read_bytes(uart.port, data, length, portMAX_DELAY);
+#if CONFIG_ESP_MODEM_ADD_DEBUG_LOGS
+        ESP_LOG_BUFFER_HEXDUMP("uart-rx", data, read_len, ESP_LOG_DEBUG);
+#endif
+        return read_len;
     }
     return 0;
 }
 
 int UartTerminal::write(uint8_t *data, size_t len)
 {
+#if CONFIG_ESP_MODEM_ADD_DEBUG_LOGS
+    ESP_LOG_BUFFER_HEXDUMP("uart-tx", data, len, ESP_LOG_DEBUG);
+#endif
     return uart_write_bytes_compat(uart.port, data, len);
 }
 

components/esp_modem/test/target/pytest_pppd.py

@@ -9,6 +9,20 @@ from threading import Event, Thread
 import netifaces
 
 
+def is_esp32(port):
+    """
+    Check if the given port is connected to an ESP32 using esptool.
+    """
+    try:
+        result = subprocess.run(
+            ['esptool.py', '--port', port, 'chip_id'],
+            stdout=subprocess.PIPE, stderr=subprocess.PIPE, check=True, text=True
+        )
+        return 'ESP32' in result.stdout
+    except subprocess.CalledProcessError:
+        return False
+
+
 def run_server(server_stop, port, server_ip, client_ip, auth, auth_user, auth_password):
     print('Starting PPP server on port: {}'.format(port))
     try:
@@ -66,13 +80,27 @@ def test_examples_protocol_pppos_connect(dut):
         )
         raise
 
-    # the PPP test env uses two ttyUSB's: one for ESP32 board, another one for ppp server
-    # use the other port for PPP server than the DUT/ESP
-    port = '/dev/ttyUSB0' if dut.serial.port == '/dev/ttyUSB1' else '/dev/ttyUSB1'
+    # the PPP test env uses three ttyUSB's: two for ESP32 board and another one for the ppp server
+    # we need to detect the server_port (for PPPD)
+    server_port = None
+    for i in ['/dev/ttyUSB0', '/dev/ttyUSB1', '/dev/ttyUSB2']:
+        if i == dut.serial.port:
+            print(f'DUT port: {i}')
+        elif is_esp32(i):
+            print(f'Some other ESP32: {i}')
+        else:
+            print(f'Port for PPPD: {i}')
+            server_port = i
+    if server_port is None:
+        print(
+            'ENV_TEST_FAILURE: Cannot locate PPPD port'
+        )
+        raise
+
     # Start the PPP server
     server_stop = Event()
     t = Thread(target=run_server,
-               args=(server_stop, port, server_ip, client_ip, auth, auth_user, auth_password))
+               args=(server_stop, server_port, server_ip, client_ip, auth, auth_user, auth_password))
     t.start()
     try:
         ppp_server_timeout = time.time() + 30

components/esp_websocket_client/esp_websocket_client.c

@@ -122,12 +122,11 @@ struct esp_websocket_client {
     uint64_t                    ping_tick_ms;
     uint64_t                    pingpong_tick_ms;
     int                         wait_timeout_ms;
-    int                         auto_reconnect;
     bool                        run;
     bool                        wait_for_pong_resp;
     bool                        selected_for_destroying;
     EventGroupHandle_t          status_bits;
-    SemaphoreHandle_t            lock;
+    SemaphoreHandle_t           lock;
     size_t                      errormsg_size;
     char                        *errormsg_buffer;
     char                        *rx_buffer;

components/mosquitto/.build-test-rules.yml

@@ -0,0 +1,3 @@
+components/mosquitto/examples/serverless_mqtt:
+  disable:
+    - if: IDF_TARGET not in ["esp32", "esp32s3", "esp32c3"]

components/mosquitto/.cz.yaml

@@ -3,6 +3,6 @@ commitizen:
   bump_message: 'bump(mosq): $current_version -> $new_version'
   pre_bump_hooks: python ../../ci/changelog.py mosquitto
   tag_format: mosq-v$version
-  version: 2.0.28~0
+  version: 2.0.20
   version_files:
   - idf_component.yml

components/mosquitto/CHANGELOG.md

@@ -1,5 +1,23 @@
+# Changelog
+
+## [2.0.20](https://github.com/espressif/esp-protocols/commits/mosq-v2.0.20)
+
+### Features
+
+- Upgrade to mosquitto v2.0.20 ([3b2c614d](https://github.com/espressif/esp-protocols/commit/3b2c614d))
+- Add support for on-message callback ([cdeab8f5](https://github.com/espressif/esp-protocols/commit/cdeab8f5))
+- Add example with two brokers synced on P2P ([d57b8c5b](https://github.com/espressif/esp-protocols/commit/d57b8c5b))
+
+### Bug Fixes
+
+- Fix dependency issues moving esp-tls to public deps ([6cce87e4](https://github.com/espressif/esp-protocols/commit/6cce87e4))
+
 ## [2.0.28~0](https://github.com/espressif/esp-protocols/commits/mosq-v2.0.28_0)
 
+### Warning
+
+Incorrect version number! This version published under `2.0.28~0` is based on upstream v2.0.18
+
 ### Features
 
 - Added support for TLS transport using ESP-TLS ([1af4bbe1](https://github.com/espressif/esp-protocols/commit/1af4bbe1))

components/mosquitto/CMakeLists.txt

@@ -81,7 +81,8 @@ idf_component_register(SRCS ${m_srcs}
                     PRIV_INCLUDE_DIRS port/priv_include port/priv_include/sys ${m_dir} ${m_src_dir}
                                       ${m_incl_dir} ${m_lib_dir} ${m_deps_dir}
                     INCLUDE_DIRS ${m_incl_dir} port/include
-                    PRIV_REQUIRES newlib esp-tls
+                    REQUIRES esp-tls
+                    PRIV_REQUIRES newlib
         )
 
 target_compile_definitions(${COMPONENT_LIB} PRIVATE "WITH_BROKER")

components/mosquitto/examples/serverless_mqtt/CMakeLists.txt

@@ -0,0 +1,6 @@
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(serverless_mqtt)

components/mosquitto/examples/serverless_mqtt/README.md

@@ -0,0 +1,53 @@
+# Brokerless MQTT Example
+
+MQTT served by (two) mosquitto's running on two ESP chips.
+
+* Leverages MQTT connectivity between two private networks without cloud premisses.
+* Creates two local MQTT servers (on ESP32x's) which are being synchronized over peer to peer connection (established via ICE protocol, by [libjuice](https://github.com/paullouisageneau/libjuice)).
+
+## How it works
+
+This example needs two ESP32 chipsets, that will create two separate Wi-Fi networks (IoT networks) used for IoT devices.
+Each IoT network is served by an MQTT server (using mosquitto component).
+This example will also synchronize these two MQTT brokers, as if there was only one IoT network with one broker.
+This example creates a peer to peer connection between two chipsets to keep them synchronize. This connection utilizes libjuice (which implements a simplified ICE-UDP) to traverse NATs, which enabling direct connection between two private networks behind NATs.
+
+* Diagram
+
+![demo](serverless.png)
+
+Here's a step-by-step procedure of establishing this remote connection:
+1) Initialize and start Wi-Fi AP (for IoT networks) and Wi-Fi station (for internet connection)
+2) Start mosquitto broker on IoT network
+3) Start libjuice to gather connection candidates
+4) Synchronize using a public MQTT broker and exchange ICE descriptors
+5) Establish ICE UDP connection between the two ESP32 chipsets
+6) Start forwarding mqtt messages
+   - Each remote datagram (received from ICE-UDP channel) is re-published to the local MQTT server
+   - Each local MQTT message (received from mosquitto on_message callback) is sent in ICE-UDP datagram
+
+## How to use this example
+
+You need two ESP32 devices that support Wi-Fi station and Wi-Fi software access point.
+
+* Configure Wi-Fi credentials for both devices on both interfaces
+  * These devices would be deployed in distinct Wi-Fi environments, so the Wi-Fi station credentials would likely be different.
+  * They also create their own IoT network (on the soft-AP interface) Wi-Fi, so the AP credentials would likely be the same, suggesting the IoT networks will be keep synchronized (even though these are two distict Wi-Fi networks).
+* Choose `CONFIG_EXAMPLE_SERVERLESS_ROLE_PEER1` for one device and `CONFIG_EXAMPLE_SERVERLESS_ROLE_PEER2` for another. It's not important which device is PEER1, since the code is symmetric, but these two devices need to have different role.
+* Optionally: You can use `idf.py` `-D` and `-B` flag to keep separate build directories and sdkconfigs for these two roles
+```
+idf.py -B build1 -DSDKCONFIG=build1/sdkconfig menuconfig build flash monitor
+```
+* Flash and run the two devices and wait for them to connect and synchronize.
+* Now you can test MQTT connectivity, for example:
+  * Join PEER1 device's AP and connect to the MQTT broker with one or more clients, subscribing to one or more topics.
+  * Join PEER2 device's AP and connect to the MQTT broker with one or more clients, subscribing to one or more topics.
+  * Whenever you publish to a topic, all subscribed clients should receive the message, no matter which Wi-Fi network they're connected to.
+
+## Warning
+
+This example uses libjuice as a dependency:
+
+* libjuice (UDP Interactive Connectivity Establishment): https://github.com/paullouisageneau/libjuice
+
+which is distributed under Mozilla Public License v2.0.

components/mosquitto/examples/serverless_mqtt/components/libjuice/CMakeLists.txt

@@ -0,0 +1,44 @@
+set(LIBJUICE_VERSION "73785387eafe15c02b6a210edb10f722474e8e14")
+set(LIBJUICE_URL "https://github.com/paullouisageneau/libjuice/archive/${LIBJUICE_VERSION}.zip")
+
+set(libjuice_dir ${CMAKE_BINARY_DIR}/libjuice/libjuice-${LIBJUICE_VERSION})
+
+# Fetch the library
+if(NOT EXISTS ${libjuice_dir})
+        message(STATUS "Downloading libjuice ${LIBJUICE_VERSION}...")
+        file(DOWNLOAD ${LIBJUICE_URL} ${CMAKE_BINARY_DIR}/libjuice.zip SHOW_PROGRESS)
+        execute_process(COMMAND unzip -o ${CMAKE_BINARY_DIR}/libjuice.zip -d ${CMAKE_BINARY_DIR}/libjuice
+                WORKING_DIRECTORY ${CMAKE_BINARY_DIR})
+endif()
+
+set(JUICE_SOURCES   ${libjuice_dir}/src/addr.c
+                    ${libjuice_dir}/src/agent.c
+                    ${libjuice_dir}/src/base64.c
+                    ${libjuice_dir}/src/conn.c
+                    ${libjuice_dir}/src/conn_mux.c
+                    ${libjuice_dir}/src/conn_poll.c
+                    ${libjuice_dir}/src/conn_thread.c
+                    ${libjuice_dir}/src/const_time.c
+                    ${libjuice_dir}/src/crc32.c
+                    ${libjuice_dir}/src/hash.c
+                    ${libjuice_dir}/src/ice.c
+                    ${libjuice_dir}/src/juice.c
+                    ${libjuice_dir}/src/log.c
+                    ${libjuice_dir}/src/server.c
+                    ${libjuice_dir}/src/stun.c
+                    ${libjuice_dir}/src/timestamp.c
+                    ${libjuice_dir}/src/turn.c
+                    ${libjuice_dir}/src/udp.c
+# Use hmac from mbedtls and random numbers from esp_random:
+#                    ${libjuice_dir}/src/hmac.c
+#                    ${libjuice_dir}/src/random.c
+        )
+
+idf_component_register(SRCS     port/juice_random.c
+                                ${JUICE_SOURCES}
+                       INCLUDE_DIRS "include"  "${libjuice_dir}/include" "${libjuice_dir}/include/juice"
+                       REQUIRES esp_netif
+                       PRIV_REQUIRES sock_utils)
+
+target_compile_options(${COMPONENT_LIB} PRIVATE "-Wno-format")
+set_source_files_properties(${libjuice_dir}/src/udp.c PROPERTIES COMPILE_FLAGS -Wno-unused-variable)

components/mosquitto/examples/serverless_mqtt/components/libjuice/include/ifaddrs.h

@@ -0,0 +1,13 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+#pragma once
+
+// Purpose of this header is to replace udp_sendto() to avoid name conflict with lwip
+// added here since ifaddrs.h is included from juice_udp sources
+#define udp_sendto juice_udp_sendto
+
+// other than that, let's just include the ifaddrs (from sock_utils)
+#include_next "ifaddrs.h"

components/mosquitto/examples/serverless_mqtt/components/libjuice/port/juice_random.c

@@ -0,0 +1,40 @@
+/**
+ * Copyright (c) 2020 Paul-Louis Ageneau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+#include "esp_random.h"
+
+void juice_random(void *buf, size_t size)
+{
+    esp_fill_random(buf, size);
+}
+
+void juice_random_str64(char *buf, size_t size)
+{
+    static const char chars64[] =
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+    size_t i = 0;
+    for (i = 0; i + 1 < size; ++i) {
+        uint8_t byte = 0;
+        juice_random(&byte, 1);
+        buf[i] = chars64[byte & 0x3F];
+    }
+    buf[i] = '\0';
+}
+
+uint32_t juice_rand32(void)
+{
+    uint32_t r = 0;
+    juice_random(&r, sizeof(r));
+    return r;
+}
+
+uint64_t juice_rand64(void)
+{
+    uint64_t r = 0;
+    juice_random(&r, sizeof(r));
+    return r;
+}

components/mosquitto/examples/serverless_mqtt/main/CMakeLists.txt

@@ -0,0 +1,4 @@
+idf_component_register(SRCS "serverless_mqtt.c"
+                            "wifi_connect.c"
+                    INCLUDE_DIRS "."
+                    REQUIRES libjuice nvs_flash mqtt json esp_wifi)

components/mosquitto/examples/serverless_mqtt/main/Kconfig.projbuild

@@ -0,0 +1,85 @@
+menu "Example Configuration"
+
+    menu "AP Configuration"
+        comment "AP Configuration"
+
+        config EXAMPLE_AP_SSID
+            string "Wi-Fi SSID"
+            default "myssid"
+            help
+                Set the SSID of Wi-Fi ap interface.
+
+        config EXAMPLE_AP_PASSWORD
+            string "Wi-Fi Password"
+            default "12345678"
+            help
+                Set the password of Wi-Fi ap interface.
+
+    endmenu
+
+    menu "STA Configuration"
+        comment "STA Configuration"
+
+        config EXAMPLE_STA_SSID
+            string "WiFi Station SSID"
+            default "mystationssid"
+            help
+                SSID for the example's sta to connect to.
+
+        config EXAMPLE_STA_PASSWORD
+            string "WiFi Station Password"
+            default "mystationpassword"
+            help
+                WiFi station password for the example to use.
+    endmenu
+
+    config EXAMPLE_MQTT_BROKER_URI
+        string "MQTT Broker URL"
+        default "mqtt://mqtt.eclipseprojects.io"
+        help
+            URL of the mqtt broker use for synchronisation and exchanging
+            ICE connect info (description and candidates).
+
+    config EXAMPLE_MQTT_SYNC_TOPIC
+        string "MQTT topic for synchronisation"
+        default "/topic/serverless_mqtt"
+        help
+            MQTT topic used fo synchronisation.
+
+    config EXAMPLE_STUN_SERVER
+        string "Hostname of STUN server"
+        default "stun.l.google.com"
+        help
+            STUN server hostname.
+
+    config EXAMPLE_MQTT_CLIENT_STACK_SIZE
+        int "Stack size for mqtt client"
+        default 16384
+        help
+            Set stack size for the mqtt client.
+            Need more stack, since calling juice API from the handler.
+
+    config EXAMPLE_MQTT_BROKER_PORT
+        int "port for the mosquitto to listen to"
+        default 1883
+        help
+            This is a port which the local mosquitto uses.
+
+    choice EXAMPLE_SERVERLESS_ROLE
+        prompt "Choose your role"
+        default EXAMPLE_SERVERLESS_ROLE_PEER1
+        help
+            Choose either peer1 or peer2.
+            It's not very important which device is peer1
+            (peer-1 sends sync messages, peer2 listens for them)
+            It is important that we have two peers,
+            one with peer1 config, another one with peer2 config
+
+        config EXAMPLE_SERVERLESS_ROLE_PEER1
+            bool "peer1"
+
+        config EXAMPLE_SERVERLESS_ROLE_PEER2
+            bool "peer2"
+    endchoice
+
+endmenu

components/mosquitto/examples/serverless_mqtt/main/idf_component.yml

@@ -0,0 +1,5 @@
+## IDF Component Manager Manifest File
+dependencies:
+  espressif/mosquitto:
+    override_path: ../../..
+  espressif/sock_utils: "*"

components/mosquitto/examples/serverless_mqtt/main/serverless_mqtt.c

@@ -0,0 +1,374 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+#include <stdio.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/event_groups.h"
+#include "mqtt_client.h"
+#include "esp_wifi.h"
+#include "esp_log.h"
+#include "esp_random.h"
+#include "esp_check.h"
+#include "esp_sleep.h"
+#include "mosq_broker.h"
+#include "juice/juice.h"
+#include "cJSON.h"
+
+#if defined(CONFIG_EXAMPLE_SERVERLESS_ROLE_PEER1)
+#define OUR_PEER "1"
+#define THEIR_PEER "2"
+#elif defined(CONFIG_EXAMPLE_SERVERLESS_ROLE_PEER2)
+#define OUR_PEER "2"
+#define THEIR_PEER "1"
+#endif
+
+#define PEER_SYNC0 BIT(0)
+#define PEER_SYNC1 BIT(1)
+#define PEER_SYNC2 BIT(2)
+#define PEER_FAIL  BIT(3)
+#define PEER_GATHER_DONE  BIT(4)
+#define PEER_DESC_PUBLISHED  BIT(5)
+#define PEER_CONNECTED  BIT(6)
+
+#define SYNC_BITS (PEER_SYNC1 | PEER_SYNC2 | PEER_FAIL)
+
+#define PUBLISH_SYNC_TOPIC CONFIG_EXAMPLE_MQTT_SYNC_TOPIC OUR_PEER
+#define SUBSCRIBE_SYNC_TOPIC CONFIG_EXAMPLE_MQTT_SYNC_TOPIC THEIR_PEER
+#define MAX_BUFFER_SIZE JUICE_MAX_SDP_STRING_LEN
+
+typedef struct message_wrap {
+    uint16_t topic_len;
+    uint16_t data_len;
+    char data[];
+} __attribute__((packed)) message_wrap_t;
+
+static const char *TAG = "serverless_mqtt" OUR_PEER;
+static char s_buffer[MAX_BUFFER_SIZE];
+static EventGroupHandle_t s_state = NULL;
+static juice_agent_t *s_agent = NULL;
+static cJSON *s_peer_desc_json = NULL;
+static char *s_peer_desc = NULL;
+static esp_mqtt_client_handle_t s_local_mqtt = NULL;
+
+char *wifi_get_ipv4(wifi_interface_t interface);
+esp_err_t wifi_connect(void);
+static esp_err_t sync_peers(void);
+static esp_err_t create_candidates(void);
+static esp_err_t create_local_client(void);
+static esp_err_t create_local_broker(void);
+
+void app_main(void)
+{
+    __attribute__((__unused__)) esp_err_t ret;
+    ESP_GOTO_ON_ERROR(wifi_connect(), err, TAG, "Failed to initialize WiFi");
+    ESP_GOTO_ON_ERROR(create_local_broker(), err, TAG, "Failed to create local broker");
+    ESP_GOTO_ON_ERROR(create_candidates(), err, TAG, "Failed to create juice candidates");
+    ESP_GOTO_ON_ERROR(sync_peers(), err, TAG, "Failed to sync with the other peer");
+    EventBits_t bits = xEventGroupWaitBits(s_state, PEER_FAIL | PEER_CONNECTED, pdFALSE, pdFALSE, pdMS_TO_TICKS(90000));
+    if (bits & PEER_CONNECTED) {
+        ESP_LOGI(TAG, "Peer is connected!");
+        ESP_GOTO_ON_ERROR(create_local_client(), err, TAG, "Failed to create forwarding mqtt client");
+        ESP_LOGI(TAG, "Everything is ready, exiting main task");
+        return;
+    }
+err:
+    ESP_LOGE(TAG, "Non recoverable error, going to sleep for some time (random, max 20s)");
+    esp_deep_sleep(1000000LL * (esp_random() % 20));
+}
+
+static void mqtt_event_handler(void *handler_args, esp_event_base_t base, int32_t event_id, void *event_data)
+{
+    esp_mqtt_event_handle_t event = event_data;
+    esp_mqtt_client_handle_t client = event->client;
+    switch ((esp_mqtt_event_id_t)event_id) {
+    case MQTT_EVENT_CONNECTED:
+        ESP_LOGI(TAG, "MQTT_EVENT_CONNECTED");
+        if (esp_mqtt_client_subscribe(client, SUBSCRIBE_SYNC_TOPIC, 1) < 0) {
+            ESP_LOGE(TAG, "Failed to subscribe to the sync topic");
+        }
+        xEventGroupSetBits(s_state, PEER_SYNC0);
+        break;
+    case MQTT_EVENT_DISCONNECTED:
+        ESP_LOGI(TAG, "MQTT_EVENT_DISCONNECTED");
+        xEventGroupSetBits(s_state, PEER_FAIL);
+        break;
+
+    case MQTT_EVENT_DATA:
+        ESP_LOGI(TAG, "MQTT_EVENT_DATA");
+        printf("TOPIC=%.*s\r\n", event->topic_len, event->topic);
+        printf("DATA=%.*s\r\n", event->data_len, event->data);
+        if (s_state == NULL || memcmp(event->topic, SUBSCRIBE_SYNC_TOPIC, event->topic_len) != 0) {
+            break;
+        }
+        EventBits_t bits = xEventGroupGetBits(s_state);
+        if (event->data_len > 1 && s_agent) {
+            cJSON *root = cJSON_Parse(event->data);
+            if (root == NULL) {
+                break;
+            }
+            cJSON *desc = cJSON_GetObjectItem(root, "desc");
+            if (desc == NULL) {
+                cJSON_Delete(root);
+                break;
+            }
+            printf("desc->valuestring:%s\n", desc->valuestring);
+            juice_set_remote_description(s_agent, desc->valuestring);
+            char cand_name[] = "cand0";
+            while (true) {
+                cJSON *cand = cJSON_GetObjectItem(root, cand_name);
+                if (cand == NULL) {
+                    break;
+                }
+                printf("%s: cand->valuestring:%s\n", cand_name, cand->valuestring);
+                juice_add_remote_candidate(s_agent, cand->valuestring);
+                cand_name[4]++;
+            }
+            cJSON_Delete(root);
+            xEventGroupSetBits(s_state, PEER_DESC_PUBLISHED); // this will complete the sync process
+            // and destroy the mqtt client
+        }
+#ifdef CONFIG_EXAMPLE_SERVERLESS_ROLE_PEER1
+        if (event->data_len == 1 && event->data[0] == '1' && (bits & PEER_SYNC2) == 0) {
+            if (esp_mqtt_client_publish(client, PUBLISH_SYNC_TOPIC, "2", 1, 1, 0) >= 0) {
+                xEventGroupSetBits(s_state, PEER_SYNC2);
+            } else {
+                xEventGroupSetBits(s_state, PEER_FAIL);
+            }
+        }
+#else
+        if (event->data_len == 1 && event->data[0] == '0' && (bits & PEER_SYNC1) == 0) {
+            if (esp_mqtt_client_publish(client, PUBLISH_SYNC_TOPIC, "1", 1, 1, 0) >= 0) {
+                xEventGroupSetBits(s_state, PEER_SYNC1);
+            }  else {
+                xEventGroupSetBits(s_state, PEER_FAIL);
+            }
+        } else if (event->data_len == 1 && event->data[0] == '2' && (bits & PEER_SYNC2) == 0) {
+            xEventGroupSetBits(s_state, PEER_SYNC2);
+        }
+#endif
+        break;
+    case MQTT_EVENT_ERROR:
+        ESP_LOGI(TAG, "MQTT_EVENT_ERROR");
+        xEventGroupSetBits(s_state, PEER_FAIL);
+        break;
+    default:
+        ESP_LOGI(TAG, "Other event id:%d", event->event_id);
+        break;
+    }
+}
+
+static esp_err_t sync_peers(void)
+{
+    esp_err_t ret = ESP_OK;
+    esp_mqtt_client_config_t mqtt_cfg = {
+        .broker.address.uri = CONFIG_EXAMPLE_MQTT_BROKER_URI,
+        .task.stack_size = CONFIG_EXAMPLE_MQTT_CLIENT_STACK_SIZE,
+    };
+    esp_mqtt_client_handle_t client = esp_mqtt_client_init(&mqtt_cfg);
+    ESP_GOTO_ON_FALSE(client, ESP_ERR_NO_MEM, err, TAG, "Failed to create mqtt client");
+    ESP_GOTO_ON_ERROR(esp_mqtt_client_register_event(client, ESP_EVENT_ANY_ID, mqtt_event_handler, NULL),
+                      err, TAG, "Failed to register mqtt event handler");
+    ESP_GOTO_ON_ERROR(esp_mqtt_client_start(client), err, TAG, "Failed to start mqtt client");
+    ESP_GOTO_ON_FALSE(xEventGroupWaitBits(s_state, PEER_SYNC0, pdTRUE, pdTRUE, pdMS_TO_TICKS(10000)),
+                      ESP_FAIL, err, TAG, "Failed to connect to the sync broker");
+    ESP_LOGI(TAG, "Waiting for the other peer...");
+    const int max_sync_retry = 60;
+    int retry = 0;
+    while (true) {
+        EventBits_t bits = xEventGroupWaitBits(s_state, SYNC_BITS, pdTRUE, pdFALSE, pdMS_TO_TICKS(1000));
+        if (bits & PEER_SYNC2) {
+            break;
+        }
+        if (bits & PEER_SYNC1) {
+            continue;
+        }
+        ESP_GOTO_ON_FALSE((bits & PEER_FAIL) == 0, ESP_FAIL, err, TAG, "Failed to sync with the other peer");
+        ESP_GOTO_ON_FALSE(retry++ < max_sync_retry, ESP_FAIL, err, TAG, "Failed to sync after %d seconds", retry);
+#ifdef CONFIG_EXAMPLE_SERVERLESS_ROLE_PEER1
+        ESP_RETURN_ON_FALSE(esp_mqtt_client_publish(client, PUBLISH_SYNC_TOPIC, "0", 1, 1, 0) >= 0,
+                            ESP_FAIL, TAG, "Failed to publish mqtt message");
+#endif
+    }
+    ESP_LOGI(TAG, "Sync done");
+    ESP_RETURN_ON_FALSE(esp_mqtt_client_publish(client, PUBLISH_SYNC_TOPIC, s_peer_desc, 0, 1, 0) >= 0,
+                        ESP_FAIL, TAG, "Failed to publish peer's description");
+    ESP_LOGI(TAG, "Waiting for the other peer description and candidates...");
+    ESP_GOTO_ON_FALSE(xEventGroupWaitBits(s_state, PEER_DESC_PUBLISHED, pdTRUE, pdTRUE, pdMS_TO_TICKS(10000)),
+                      ESP_FAIL, err, TAG, "Timeout in waiting for the other peer candidates");
+err:
+    free(s_peer_desc);
+    esp_mqtt_client_destroy(client);
+    return ret;
+}
+
+static void juice_state(juice_agent_t *agent, juice_state_t state, void *user_ptr)
+{
+    ESP_LOGI(TAG, "JUICE state change: %s", juice_state_to_string(state));
+    if (state == JUICE_STATE_CONNECTED) {
+        xEventGroupSetBits(s_state, PEER_CONNECTED);
+    } else if (state == JUICE_STATE_FAILED || state == JUICE_STATE_DISCONNECTED) {
+        esp_restart();
+    }
+}
+
+static void juice_candidate(juice_agent_t *agent, const char *sdp, void *user_ptr)
+{
+    static uint8_t cand_nr = 0;
+    if (s_peer_desc_json && cand_nr < 10) { // supporting only 10 candidates
+        char cand_name[] = "cand0";
+        cand_name[4] += cand_nr++;
+        cJSON_AddStringToObject(s_peer_desc_json, cand_name, sdp);
+    }
+}
+
+static void juice_gathering_done(juice_agent_t *agent, void *user_ptr)
+{
+    ESP_LOGI(TAG, "Gathering done");
+    if (s_state) {
+        xEventGroupSetBits(s_state, PEER_GATHER_DONE);
+    }
+}
+
+#define ALIGN(size) (((size) + 3U) & ~(3U))
+
+static void juice_recv(juice_agent_t *agent, const char *data, size_t size, void *user_ptr)
+{
+    if (s_local_mqtt) {
+        message_wrap_t *message = (message_wrap_t *)data;
+        int topic_len = message->topic_len;
+        int payload_len = message->data_len;
+        int topic_len_aligned = ALIGN(topic_len);
+        char *topic = message->data;
+        char *payload = message->data + topic_len_aligned;
+        if (topic_len + topic_len_aligned + 4 > size) {
+            ESP_LOGE(TAG, "Received invalid message");
+            return;
+        }
+        ESP_LOGI(TAG, "forwarding remote message: topic:%s", topic);
+        ESP_LOGI(TAG, "forwarding remote message: payload:%.*s", payload_len, payload);
+        esp_mqtt_client_publish(s_local_mqtt, topic, payload, payload_len, 0, 0);
+    }
+}
+
+static esp_err_t create_candidates(void)
+{
+    ESP_RETURN_ON_FALSE(s_state = xEventGroupCreate(), ESP_ERR_NO_MEM, TAG, "Failed to create state event group");
+    s_peer_desc_json = cJSON_CreateObject();
+    esp_err_t ret = ESP_OK;
+    juice_set_log_level(JUICE_LOG_LEVEL_INFO);
+    juice_config_t config = { .stun_server_host = CONFIG_EXAMPLE_STUN_SERVER,
+                              .bind_address = wifi_get_ipv4(WIFI_IF_STA),
+                              .stun_server_port = 19302,
+                              .cb_state_changed = juice_state,
+                              .cb_candidate = juice_candidate,
+                              .cb_gathering_done = juice_gathering_done,
+                              .cb_recv = juice_recv,
+                            };
+
+    s_agent = juice_create(&config);
+    ESP_RETURN_ON_FALSE(s_agent, ESP_FAIL, TAG, "Failed to create juice agent");
+    ESP_GOTO_ON_FALSE(juice_get_local_description(s_agent, s_buffer, MAX_BUFFER_SIZE) == JUICE_ERR_SUCCESS,
+                      ESP_FAIL, err, TAG, "Failed to get local description");
+    ESP_LOGI(TAG, "desc: %s", s_buffer);
+    cJSON_AddStringToObject(s_peer_desc_json, "desc", s_buffer);
+
+    ESP_GOTO_ON_FALSE(juice_gather_candidates(s_agent) == JUICE_ERR_SUCCESS,
+                      ESP_FAIL, err, TAG, "Failed to start gathering candidates");
+    ESP_GOTO_ON_FALSE(xEventGroupWaitBits(s_state, PEER_GATHER_DONE, pdTRUE, pdTRUE, pdMS_TO_TICKS(30000)),
+                      ESP_FAIL, err, TAG, "Failed to connect to the sync broker");
+    s_peer_desc = cJSON_Print(s_peer_desc_json);
+    ESP_LOGI(TAG, "desc: %s", s_peer_desc);
+    cJSON_Delete(s_peer_desc_json);
+    return ESP_OK;
+
+err:
+    juice_destroy(s_agent);
+    s_agent = NULL;
+    cJSON_Delete(s_peer_desc_json);
+    s_peer_desc_json = NULL;
+    return ret;
+}
+
+static void local_handler(void *args, esp_event_base_t base, int32_t id, void *data)
+{
+    switch (id) {
+    case MQTT_EVENT_CONNECTED:
+        ESP_LOGI(TAG, "local client connected");
+        break;
+    case MQTT_EVENT_DISCONNECTED:
+        ESP_LOGI(TAG, "local client disconnected");
+        break;
+
+    case MQTT_EVENT_ERROR:
+        ESP_LOGI(TAG, "local client error");
+        break;
+    default:
+        ESP_LOGI(TAG, "local client event id:%d", (int)id);
+        break;
+    }
+}
+
+static esp_err_t create_local_client(void)
+{
+    esp_err_t ret = ESP_OK;
+    esp_mqtt_client_config_t mqtt_cfg = {
+        .broker.address.transport = MQTT_TRANSPORT_OVER_TCP,
+        .broker.address.hostname = wifi_get_ipv4(WIFI_IF_AP),
+        .broker.address.port = CONFIG_EXAMPLE_MQTT_BROKER_PORT,
+        .task.stack_size = CONFIG_EXAMPLE_MQTT_CLIENT_STACK_SIZE,
+        .credentials.client_id = "local_mqtt"
+    };
+    s_local_mqtt = esp_mqtt_client_init(&mqtt_cfg);
+    ESP_GOTO_ON_FALSE(s_local_mqtt, ESP_ERR_NO_MEM, err, TAG, "Failed to create mqtt client");
+    ESP_GOTO_ON_ERROR(esp_mqtt_client_register_event(s_local_mqtt, ESP_EVENT_ANY_ID, local_handler, NULL),
+                      err, TAG, "Failed to register mqtt event handler");
+    ESP_GOTO_ON_ERROR(esp_mqtt_client_start(s_local_mqtt), err, TAG, "Failed to start mqtt client");
+
+    return ESP_OK;
+err:
+    esp_mqtt_client_destroy(s_local_mqtt);
+    s_local_mqtt = NULL;
+    return ret;
+}
+
+static void handle_message(char *client, char *topic, char *payload, int len, int qos, int retain)
+{
+    if (client && strcmp(client, "local_mqtt") == 0 ) {
+        // This is our little local client -- do not forward
+        return;
+    }
+    ESP_LOGI(TAG, "handle_message topic:%s", topic);
+    ESP_LOGI(TAG, "handle_message data:%.*s", len, payload);
+    ESP_LOGI(TAG, "handle_message qos=%d, retain=%d", qos, retain);
+    if (s_local_mqtt && s_agent) {
+        int topic_len = strlen(topic) + 1; // null term
+        int topic_len_aligned = ALIGN(topic_len);
+        int total_msg_len = 2 + 2 /* msg_wrap header */ + topic_len_aligned + len;
+        if (total_msg_len > MAX_BUFFER_SIZE) {
+            ESP_LOGE(TAG, "Fail to forward, message too long");
+            return;
+        }
+        message_wrap_t *message = (message_wrap_t *)s_buffer;
+        message->topic_len = topic_len;
+        message->data_len = len;
+
+        memcpy(s_buffer + 4, topic, topic_len);
+        memcpy(s_buffer + 4 + topic_len_aligned, payload, len);
+        juice_send(s_agent, s_buffer, total_msg_len);
+    }
+}
+
+static void broker_task(void *ctx)
+{
+    struct mosq_broker_config config = { .host = wifi_get_ipv4(WIFI_IF_AP), .port = CONFIG_EXAMPLE_MQTT_BROKER_PORT, .handle_message_cb = handle_message };
+    mosq_broker_run(&config);
+    vTaskDelete(NULL);
+}
+
+static esp_err_t create_local_broker(void)
+{
+    return xTaskCreate(broker_task, "mqtt_broker_task", 1024 * 32, NULL, 5, NULL) == pdTRUE ?
+           ESP_OK : ESP_FAIL;
+}

components/mosquitto/examples/serverless_mqtt/main/wifi_connect.c

@@ -0,0 +1,122 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+#include "nvs_flash.h"
+#include "esp_event.h"
+#include "esp_netif.h"
+#include "esp_check.h"
+#include "esp_wifi.h"
+#include "esp_mac.h"
+
+#define WIFI_CONNECTED_BIT BIT0
+#define WIFI_FAIL_BIT      BIT1
+
+static const char *TAG = "serverless_wifi";
+static EventGroupHandle_t s_wifi_events;
+static int s_retry_num = 0;
+static const int s_max_retry = 30;
+
+static void wifi_event_handler(void *arg, esp_event_base_t event_base,
+                               int32_t event_id, void *event_data)
+{
+    if (event_id == WIFI_EVENT_AP_STACONNECTED) {
+        wifi_event_ap_staconnected_t *event = (wifi_event_ap_staconnected_t *) event_data;
+        ESP_LOGI(TAG, "station "MACSTR" join, AID=%d",
+                 MAC2STR(event->mac), event->aid);
+    } else if (event_id == WIFI_EVENT_AP_STADISCONNECTED) {
+        wifi_event_ap_stadisconnected_t *event = (wifi_event_ap_stadisconnected_t *) event_data;
+        ESP_LOGI(TAG, "station "MACSTR" leave, AID=%d",
+                 MAC2STR(event->mac), event->aid);
+    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START) {
+        esp_wifi_connect();
+    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) {
+        if (s_retry_num < s_max_retry) {
+            esp_wifi_connect();
+            s_retry_num++;
+            ESP_LOGI(TAG, "retry to connect to the AP");
+        } else {
+            xEventGroupSetBits(s_wifi_events, WIFI_FAIL_BIT);
+        }
+        ESP_LOGI(TAG, "Connect to the AP fail");
+    } else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
+        ip_event_got_ip_t *event = (ip_event_got_ip_t *) event_data;
+        ESP_LOGI(TAG, "Got ip:" IPSTR, IP2STR(&event->ip_info.ip));
+        s_retry_num = 0;
+        xEventGroupSetBits(s_wifi_events, WIFI_CONNECTED_BIT);
+    }
+}
+
+esp_err_t wifi_connect(void)
+{
+    esp_err_t ret = ESP_OK;
+    ESP_GOTO_ON_FALSE(s_wifi_events = xEventGroupCreate(), ESP_ERR_NO_MEM, err, TAG, "Failed to create wifi_events");
+    ESP_GOTO_ON_ERROR(nvs_flash_init(), err, TAG, "Failed to init nvs flash");
+    ESP_GOTO_ON_ERROR(esp_netif_init(), err, TAG, "Failed to init esp_netif");
+    ESP_GOTO_ON_ERROR(esp_event_loop_create_default(), err, TAG, "Failed to create default event loop");
+    ESP_GOTO_ON_ERROR(esp_event_handler_register(WIFI_EVENT, ESP_EVENT_ANY_ID, wifi_event_handler, NULL),
+                      err, TAG, "Failed to register WiFi event handler");
+    ESP_GOTO_ON_ERROR(esp_event_handler_register(IP_EVENT, IP_EVENT_STA_GOT_IP, wifi_event_handler, NULL),
+                      err, TAG, "Failed to register IP event handler");
+
+    // Initialize WiFi
+    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+    ESP_GOTO_ON_ERROR(esp_wifi_init(&cfg), err, TAG, "Failed to initialize WiFi");
+    ESP_GOTO_ON_ERROR(esp_wifi_set_mode(WIFI_MODE_APSTA), err, TAG, "Failed to set STA+AP mode");
+
+    // Initialize AP
+    esp_netif_t *ap = esp_netif_create_default_wifi_ap();
+    ESP_GOTO_ON_FALSE(ap, ESP_FAIL, err, TAG, "Failed to create AP network interface");
+    wifi_config_t wifi_ap_config = {
+        .ap = {
+            .ssid = CONFIG_EXAMPLE_AP_SSID,
+            .password = CONFIG_EXAMPLE_AP_PASSWORD,
+            .authmode = WIFI_AUTH_WPA2_PSK,
+            .max_connection = 4,
+        },
+    };
+    ESP_GOTO_ON_ERROR(esp_wifi_set_config(WIFI_IF_AP, &wifi_ap_config), err, TAG, "Failed to set AP config");
+
+
+    // Initialize STA
+    esp_netif_t *sta = esp_netif_create_default_wifi_sta();
+    ESP_GOTO_ON_FALSE(sta, ESP_FAIL, err, TAG, "Failed to create WiFi station network interface");
+    wifi_config_t wifi_sta_config = {
+        .sta = {
+            .ssid = CONFIG_EXAMPLE_STA_SSID,
+            .password = CONFIG_EXAMPLE_STA_PASSWORD,
+        },
+    };
+    ESP_GOTO_ON_ERROR(esp_wifi_set_config(WIFI_IF_STA, &wifi_sta_config), err, TAG, "Failed to set STA config");
+
+    // Start WiFi
+    ESP_GOTO_ON_ERROR(esp_wifi_start(), err, TAG, "Failed to start WiFi");
+
+    // Wait for connection
+    EventBits_t bits = xEventGroupWaitBits(s_wifi_events, WIFI_CONNECTED_BIT | WIFI_FAIL_BIT,
+                                           pdFALSE, pdFALSE, pdMS_TO_TICKS(30000));
+    ESP_GOTO_ON_FALSE((bits & WIFI_CONNECTED_BIT) == WIFI_CONNECTED_BIT, ESP_FAIL, err,
+                      TAG, "Failed to obtain IP address from WiFi station");
+    return ESP_OK;
+err:
+    esp_wifi_stop();
+    esp_wifi_deinit();
+    nvs_flash_deinit();
+    esp_netif_deinit();
+    esp_event_loop_delete_default();
+    return ret;
+
+}
+
+_Thread_local char s_ipv4_addr[4 * 4]; // 4 octets + '.'/term
+
+char *wifi_get_ipv4(wifi_interface_t interface)
+{
+    esp_netif_t *netif = esp_netif_get_handle_from_ifkey(interface == WIFI_IF_AP ? "WIFI_AP_DEF" : "WIFI_STA_DEF");
+    ESP_RETURN_ON_FALSE(netif, NULL, TAG, "Failed to find default Wi-Fi netif");
+    esp_netif_ip_info_t ip_info;
+    ESP_RETURN_ON_FALSE(esp_netif_get_ip_info(netif, &ip_info) == ESP_OK, NULL, TAG, "Failed to get IP from netif");
+    ESP_RETURN_ON_FALSE(esp_ip4addr_ntoa(&ip_info.ip, s_ipv4_addr, sizeof(s_ipv4_addr)) != NULL, NULL, TAG, "Failed to convert IP");
+    return s_ipv4_addr;
+}

components/mosquitto/examples/serverless_mqtt/sdkconfig.defaults

@@ -0,0 +1,3 @@
+CONFIG_PARTITION_TABLE_SINGLE_APP_LARGE=y
+CONFIG_ESP_MAIN_TASK_STACK_SIZE=16384
+CONFIG_PTHREAD_TASK_STACK_SIZE_DEFAULT=32768

components/mosquitto/idf_component.yml

@@ -1,4 +1,4 @@
-version: "2.0.28~0"
+version: "2.0.20~0"
 url: https://github.com/espressif/esp-protocols/tree/master/components/mosquitto
 description: The component provides a simple ESP32 port of mosquitto broker
 dependencies:

components/mosquitto/port/broker.c

@@ -101,6 +101,8 @@ void mosq_broker_stop(void)
     run = 0;
 }
 
+extern mosq_message_cb_t g_mosq_message_callback;
+
 int mosq_broker_run(struct mosq_broker_config *broker_config)
 {
 
@@ -125,6 +127,9 @@ int mosq_broker_run(struct mosq_broker_config *broker_config)
     if (broker_config->tls_cfg) {
         net__set_tls_config(broker_config->tls_cfg);
     }
+    if (broker_config->handle_message_cb) {
+        g_mosq_message_callback = broker_config->handle_message_cb;
+    }
 
     db.config = &config;
 

components/mosquitto/port/callbacks.c

@@ -13,7 +13,9 @@
 #include "util_mosq.h"
 #include "utlist.h"
 #include "lib_load.h"
+#include "mosq_broker.h"
 
+mosq_message_cb_t g_mosq_message_callback = NULL;
 
 int mosquitto_callback_register(
     mosquitto_plugin_id_t *identifier,
@@ -44,5 +46,8 @@ void plugin__handle_disconnect(struct mosquitto *context, int reason)
 
 int plugin__handle_message(struct mosquitto *context, struct mosquitto_msg_store *stored)
 {
+    if (g_mosq_message_callback) {
+        g_mosq_message_callback(context->id, stored->topic, stored->payload, stored->payloadlen, stored->qos, stored->retain);
+    }
     return MOSQ_ERR_SUCCESS;
 }

components/mosquitto/port/include/mosq_broker.h

@@ -9,6 +9,7 @@
 
 struct mosquitto__config;
 
+typedef void (*mosq_message_cb_t)(char *client, char *topic, char *data, int len, int qos, int retain);
 /**
  * @brief Mosquitto configuration structure
  *
@@ -24,6 +25,10 @@ struct mosq_broker_config {
                                      * You can open the respective docs with this idf.py command:
                                      * `idf.py docs -sp api-reference/protocols/esp_tls.html`
                                      */
+    void (*handle_message_cb)(char *client, char *topic, char *data, int len, int qos, int retain); /*!<
+                                     * On message callback. If configured, user function is called
+                                     * whenever mosquitto processes a message.
+                                     */
 };
 
 /**

components/sock_utils/.cz.yaml

@@ -3,6 +3,6 @@ commitizen:
   bump_message: 'bump(sockutls): $current_version -> $new_version'
   pre_bump_hooks: python ../../ci/changelog.py sock_utils
   tag_format: sock_utils-v$version
-  version: 0.1.0
+  version: 0.2.0
   version_files:
   - idf_component.yml

components/sock_utils/CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## [0.2.0](https://github.com/espressif/esp-protocols/commits/sock_utils-v0.2.0)
+
+### Features
+
+- Declare socketpair and gai_strerror via standard headers ([b090a3cb](https://github.com/espressif/esp-protocols/commit/b090a3cb))
+- Add support for gethostname() ([f7c0b756](https://github.com/espressif/esp-protocols/commit/f7c0b756))
+
 ## [0.1.0](https://github.com/espressif/esp-protocols/commits/sock_utils-v0.1.0)
 
 ### Features

components/sock_utils/CMakeLists.txt

@@ -2,5 +2,15 @@ idf_component_register(SRCS "src/getnameinfo.c"
                             "src/ifaddrs.c"
                             "src/gai_strerror.c"
                             "src/socketpair.c"
+                            "src/gethostname.c"
                        INCLUDE_DIRS "include"
                        PRIV_REQUIRES lwip esp_netif)
+
+# To support declarations from standard headers in lwip component
+# - socket pair from lwip/sockets.h
+# - gai_strerror from lwip/netdb.h
+# also need to make lwip depend on the sock_utils lib
+idf_component_get_property(lwip lwip COMPONENT_LIB)
+target_compile_definitions(${lwip} PUBLIC LWIP_SOCKET_HAS_SOCKETPAIR=1)
+target_compile_definitions(${lwip} PUBLIC LWIP_NETDB_HAS_GAI_STRERROR=1)
+target_link_libraries(${lwip} PUBLIC ${COMPONENT_LIB})

components/sock_utils/README.md

@@ -6,12 +6,17 @@ This component provides simplified implementations of common socket-related util
 ## Supported Functions
 
 
-| API              | Description                                                 | Limitations                                                       |
-|------------------|-------------------------------------------------------------|-------------------------------------------------------------------|
-| `ifaddrs()`      | Retrieves interface addresses using `esp_netif`             | IPv4 addresses only                                               |
-| `socketpair()`   | Creates a pair of connected sockets using `lwIP` loopback stream sockets | IPv4 sockets only                                    |
-| `pipe()`         | Wraps `socketpair()` to provide unidirectional pipe-like functionality | Uses bidirectional sockets in place of true pipes  |
-| `getnameinfo()`  | Converts IP addresses to human-readable form using `lwIP`'s `inet_ntop()` | IPv4 only; supports `NI_NUMERICHOST` and `NI_NUMERICSERV` flags only |
-| `gai_strerror()` | Returns error code as a string                              | Simple numeric string representation only                         |
+| API                | Description                                                 | Limitations                                                       | Declared in                            |
+|--------------------|-------------------------------------------------------------|-------------------------------------------------------------------|----------------------------------------|
+| `ifaddrs()`        | Retrieves interface addresses using `esp_netif`             | IPv4 addresses only                                               | `ifaddrs.h`                            |
+| `socketpair()` *)  | Creates a pair of connected sockets using `lwIP` loopback stream sockets | IPv4 sockets only                                    | `socketpair.h`, `sys/socket.h` **)     |
+| `pipe()`       *) | Wraps `socketpair()` to provide unidirectional pipe-like functionality | Uses bidirectional sockets in place of true pipes  | `socketpair.h`, `unistd.h` ***)        |
+| `getnameinfo()`    | Converts IP addresses to human-readable form using `lwIP`'s `inet_ntop()` | IPv4 only; supports `NI_NUMERICHOST` and `NI_NUMERICSERV` flags only | `getnameinfo.h`, `netdb.h` in ESP-IDF  |
+| `gai_strerror()`   | Returns error code as a string                              | Simple numeric string representation only                         | `gai_strerror.h`, `netdb.h` **)        |
+| `gethostname()`    | Returns lwip netif hostname                                 | Not a system-wide hostname, but interface specific hostname       | `gethostname.h`, `unistd.h` in ESP-IDF |
 
-**Note**: `socketpair()` and `pipe()` are built on top of `lwIP` TCP sockets, inheriting the same characteristics. For instance, the maximum transmit buffer size is based on the `TCP_SND_BUF` setting.
+**Notes**:
+
+- **`*)`** `socketpair()` and `pipe()` are built on top of `lwIP` TCP sockets, inheriting the same characteristics. For instance, the maximum transmit buffer size is based on the `TCP_SND_BUF` setting.
+- **`**)`** `socketpair()` and `gai_strerror()` are declared in sock_utils header files, the declaration is propagated to ESP-IDF from v5.5 to the official header files. If you're using older IDF version, you need to manually pre-include related header files from the sock_utils public include directory.
+- **`***)`** `pipe()` is declared in compiler's `sys/unistd.h`.

components/sock_utils/idf_component.yml

@@ -1,4 +1,4 @@
-version: 0.1.0
+version: 0.2.0
 description: The component provides helper implementation of common system/socket utilities
 url: https://github.com/espressif/esp-protocols/tree/master/components/sock_utils
 dependencies:

components/sock_utils/include/gethostname.h

@@ -0,0 +1,51 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#pragma once
+
+#include <unistd.h>
+#include "sdkconfig.h"
+
+#ifdef CONFIG_IDF_TARGET_LINUX
+// namespace with esp_ on linux to avoid conflict of symbols
+#define gethostname esp_gethostname
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Retrieves the hostname of the device.
+ *
+ * This function provides the hostname associated with the network interface.
+ * Unlike the standard behavior where the hostname represents a system-wide name,
+ * this implementation returns lwip netif hostname (used as a hostname in DHCP packets)
+ *
+ * @param[out] name A pointer to a buffer where the hostname will be stored.
+ *                  The buffer must be allocated by the caller.
+ * @param[in] len   The size of the buffer pointed to by @p name. The hostname,
+ *                  including the null-terminator, must fit within this size.
+ *
+ * @return
+ *   - 0 on success
+ *   - -1 on error, with `errno` set to indicate the error:
+ *     - `EINVAL`: Invalid argument, name is NULL, or hostname is too long
+ *
+ * @note This implementation retrieves the hostname associated with the network
+ * interface using the `esp_netif_get_hostname()` function, which in turn
+ * returns lwip netif hostname used in DHCP packets if LWIP_NETIF_HOSTNAME=1 (hardcoded)
+ * in ESP-IDF lwip port.
+ * As there could be multiple network interfaces in the system, the logic tries
+ * to find the default (active) netif first, then it looks for any (inactive) netif
+ * with highest route priority. If none of the above found or esp_netif_get_hostname() fails
+ * for the selected interface, this API returns the default value of `CONFIG_LWIP_LOCAL_HOSTNAME`,
+ * the local hostname from lwip component configuration menu.
+ */
+int gethostname(char *name, size_t len);
+
+#ifdef __cplusplus
+}
+#endif

components/sock_utils/include/netdb_macros.h

@@ -32,3 +32,10 @@
 #ifndef AF_UNIX
 #define AF_UNIX         1
 #endif
+
+#ifndef PF_LOCAL
+/*
+ * In POSIX, AF_UNIX and PF_LOCAL are essentially synonymous.
+ */
+#define PF_LOCAL        AF_UNIX
+#endif

components/sock_utils/src/gethostname.c

@@ -0,0 +1,46 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#include <string.h>
+#include "gethostname.h"
+#include "esp_netif.h"
+#include "errno.h"
+#include "esp_log.h"
+
+
+static bool highest_prio_netif(esp_netif_t *netif, void *ctx)
+{
+    esp_netif_t **highest_so_far = ctx;
+    if (esp_netif_get_route_prio(netif) > esp_netif_get_route_prio(*highest_so_far)) {
+        *highest_so_far = netif;
+    }
+    return false;   // go over the entire list to find the netif with the highest route-prio
+}
+
+int gethostname(char *name, size_t len)
+{
+    if (name == NULL) {
+        errno = EINVAL;
+        return -1;
+    }
+    const char *netif_hostname = CONFIG_LWIP_LOCAL_HOSTNAME;    // default value from Kconfig
+
+    // Find the default netif
+    esp_netif_t *default_netif = esp_netif_get_default_netif();
+    if (default_netif == NULL) {    // if no netif is active/up -> find the highest prio netif
+        esp_netif_find_if(highest_prio_netif, &default_netif);
+    }
+    // now the `default_netif` could be NULL and/or the esp_netif_get_hostname() could fail
+    // but we ignore the return code, as if it fails, the `netif_hostname` still holds the default value
+    esp_netif_get_hostname(default_netif, &netif_hostname);
+
+    size_t hostname_len;
+    if (netif_hostname == NULL || len < (hostname_len = strlen(netif_hostname) + 1)) { // including the NULL terminator
+        errno = EINVAL;
+        return -1;
+    }
+    memcpy(name, netif_hostname, hostname_len);
+    return 0;
+}

components/sock_utils/test/host/main/test_sock_utils.cpp

@@ -3,6 +3,7 @@
  *
  * SPDX-License-Identifier: Apache-2.0
  */
+#include "gethostname.h"
 #include "ifaddrs.h"
 #include "esp_netif.h"
 #include "esp_event.h"
@@ -148,6 +149,30 @@ TEST_CASE("gai_strerror()", "[sock_utils]")
     CHECK(str_error != NULL);
 }
 
+TEST_CASE("gethostname()", "[sock_utils]")
+{
+    const char *test_netif_name = "station";
+    char hostname[32];
+    int ret;
+
+    // expect failure
+    ret = gethostname(hostname, strlen(CONFIG_LWIP_LOCAL_HOSTNAME) - 1);
+    CHECK(ret == -1);
+
+    // happy flow with the default name
+    ret = gethostname(hostname, sizeof(hostname));
+    CHECK(ret == 0);
+    CHECK(strcmp(hostname, CONFIG_LWIP_LOCAL_HOSTNAME) == 0);
+
+    // happy flow with the netif name
+    esp_netif_t *esp_netif = create_test_netif(test_netif_name, 1);
+    REQUIRE(esp_netif != NULL);
+    CHECK(esp_netif_set_hostname(esp_netif, test_netif_name) == ESP_OK);
+    ret = gethostname(hostname, sizeof(hostname));
+    CHECK(ret == 0);
+    CHECK(strcmp(hostname, test_netif_name) == 0);
+    esp_netif_destroy(esp_netif);
+}
 
 extern "C" void app_main(void)
 {