esp_modem: Refactor the modem to a standalone managed component

esp_modem/examples/ap_to_pppos/CMakeLists.txt

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+# 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 3.5)
+
+set(EXTRA_COMPONENT_DIRS "../..")
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(ap-to-pppos)

esp_modem/examples/ap_to_pppos/Makefile

@@ -0,0 +1,9 @@
+#
+# This is a project Makefile. It is assumed the directory this Makefile resides in is a
+# project subdirectory.
+#
+
+PROJECT_NAME := ap-to-pppos
+
+include $(IDF_PATH)/make/project.mk
+

esp_modem/examples/ap_to_pppos/README.md

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+# PPPoS simple client example
+
+(See the README.md file in the upper level 'examples' directory for more information about examples.)
+
+## Overview
+This example focuses on the networking part, enables forwarding packets between network interfaces. It creates a WiFi soft AP, which uses NAT to forward packets to and from the PPP network
+interface.
+
+## How to use this example
+
+See the README.md file in the upper level `pppos` directory for more information about the PPPoS examples.

esp_modem/examples/ap_to_pppos/main/CMakeLists.txt

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+idf_component_register(SRCS "ap2pppos_example_main.c"
+                            "modem_board.c"
+                    INCLUDE_DIRS ".")

esp_modem/examples/ap_to_pppos/main/Kconfig.projbuild

@@ -0,0 +1,26 @@
+menu "Example Configuration"
+
+    config ESP_WIFI_SSID
+        string "WiFi SSID"
+        default "myssid"
+        help
+            SSID (network name) for the example to connect to.
+
+    config ESP_WIFI_PASSWORD
+        string "WiFi Password"
+        default "mypassword"
+        help
+            WiFi password (WPA or WPA2) for the example to use.
+    config ESP_WIFI_CHANNEL
+        int "WiFi Channel"
+        range 1 13
+        default 1
+        help
+            WiFi channel (network channel) for the example to use.
+
+    config ESP_MAX_STA_CONN
+        int "Maximal STA connections"
+        default 4
+        help
+            Max number of the STA connects to AP.
+endmenu

esp_modem/examples/ap_to_pppos/main/ap2pppos_example_main.c

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+/*  softAP to PPPoS Example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+#include <string.h>
+#include "esp_system.h"
+#include "esp_wifi.h"
+#include "esp_event.h"
+#include "esp_log.h"
+#include "nvs_flash.h"
+#include "esp_modem.h"
+#include "lwip/lwip_napt.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/event_groups.h"
+
+#define EXAMPLE_ESP_WIFI_SSID      CONFIG_ESP_WIFI_SSID
+#define EXAMPLE_ESP_WIFI_PASS      CONFIG_ESP_WIFI_PASSWORD
+#define EXAMPLE_ESP_WIFI_CHANNEL   CONFIG_ESP_WIFI_CHANNEL
+#define EXAMPLE_MAX_STA_CONN       CONFIG_ESP_MAX_STA_CONN
+
+static const char *TAG = "ap-2-pppos";
+static EventGroupHandle_t event_group = NULL;
+static const int CONNECT_BIT = BIT0;
+static const int DISCONNECT_BIT = BIT1;
+
+static void on_modem_event(void *arg, esp_event_base_t event_base,
+                           int32_t event_id, void *event_data)
+{
+    if (event_base == IP_EVENT) {
+        ESP_LOGD(TAG, "IP event! %d", event_id);
+        if (event_id == IP_EVENT_PPP_GOT_IP) {
+            esp_netif_dns_info_t dns_info;
+
+            ip_event_got_ip_t *event = (ip_event_got_ip_t *)event_data;
+            esp_netif_t *netif = event->esp_netif;
+
+            ESP_LOGI(TAG, "Modem Connect to PPP Server");
+            ESP_LOGI(TAG, "~~~~~~~~~~~~~~");
+            ESP_LOGI(TAG, "IP          : " IPSTR, IP2STR(&event->ip_info.ip));
+            ESP_LOGI(TAG, "Netmask     : " IPSTR, IP2STR(&event->ip_info.netmask));
+            ESP_LOGI(TAG, "Gateway     : " IPSTR, IP2STR(&event->ip_info.gw));
+            esp_netif_get_dns_info(netif, 0, &dns_info);
+            ESP_LOGI(TAG, "Name Server1: " IPSTR, IP2STR(&dns_info.ip.u_addr.ip4));
+            esp_netif_get_dns_info(netif, 1, &dns_info);
+            ESP_LOGI(TAG, "Name Server2: " IPSTR, IP2STR(&dns_info.ip.u_addr.ip4));
+            ESP_LOGI(TAG, "~~~~~~~~~~~~~~");
+            xEventGroupSetBits(event_group, CONNECT_BIT);
+
+            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!");
+            ip_event_got_ip6_t *event = (ip_event_got_ip6_t *)event_data;
+            ESP_LOGI(TAG, "Got IPv6 address " IPV6STR, IPV62STR(event->ip6_info.ip));
+        }
+    } else if (event_base == ESP_MODEM_EVENT) {
+        ESP_LOGD(TAG, "Modem event! %d", event_id);
+
+    }
+}
+
+
+static esp_err_t set_dhcps_dns(esp_netif_t *netif, uint32_t addr)
+{
+    esp_netif_dns_info_t dns;
+    dns.ip.u_addr.ip4.addr = addr;
+    dns.ip.type = IPADDR_TYPE_V4;
+    dhcps_offer_t dhcps_dns_value = OFFER_DNS;
+    ESP_ERROR_CHECK(esp_netif_dhcps_option(netif, ESP_NETIF_OP_SET, ESP_NETIF_DOMAIN_NAME_SERVER, &dhcps_dns_value, sizeof(dhcps_dns_value)));
+    ESP_ERROR_CHECK(esp_netif_set_dns_info(netif, ESP_NETIF_DNS_MAIN, &dns));
+    return ESP_OK;
+}
+
+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);
+    }
+}
+
+void wifi_init_softap(void)
+{
+
+    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
+
+    ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT,
+                                                        ESP_EVENT_ANY_ID,
+                                                        &wifi_event_handler,
+                                                        NULL,
+                                                        NULL));
+
+    wifi_config_t wifi_config = {
+        .ap = {
+            .ssid = EXAMPLE_ESP_WIFI_SSID,
+            .ssid_len = strlen(EXAMPLE_ESP_WIFI_SSID),
+            .channel = EXAMPLE_ESP_WIFI_CHANNEL,
+            .password = EXAMPLE_ESP_WIFI_PASS,
+            .max_connection = EXAMPLE_MAX_STA_CONN,
+            .authmode = WIFI_AUTH_WPA_WPA2_PSK
+        },
+    };
+    if (strlen(EXAMPLE_ESP_WIFI_PASS) == 0) {
+        wifi_config.ap.authmode = WIFI_AUTH_OPEN;
+    }
+
+    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_AP));
+    ESP_ERROR_CHECK(esp_wifi_set_config(ESP_IF_WIFI_AP, &wifi_config));
+    ESP_ERROR_CHECK(esp_wifi_start());
+
+    ESP_LOGI(TAG, "wifi_init_softap finished. SSID:%s password:%s channel:%d",
+             EXAMPLE_ESP_WIFI_SSID, EXAMPLE_ESP_WIFI_PASS, EXAMPLE_ESP_WIFI_CHANNEL);
+}
+
+esp_modem_dce_t *sim7600_board_create(esp_modem_dce_config_t *config);
+
+void app_main(void)
+{
+    //Initialize NVS
+    esp_err_t ret = nvs_flash_init();
+    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+      ESP_ERROR_CHECK(nvs_flash_erase());
+      ret = nvs_flash_init();
+    }
+    ESP_ERROR_CHECK(ret);
+
+    ESP_ERROR_CHECK(esp_netif_init());
+    ESP_ERROR_CHECK(esp_event_loop_create_default());
+    event_group = xEventGroupCreate();
+
+    // init the DTE
+    esp_modem_dte_config_t dte_config = ESP_MODEM_DTE_DEFAULT_CONFIG();
+    dte_config.event_task_stack_size = 4096;
+    dte_config.rx_buffer_size = 16384;
+    dte_config.tx_buffer_size = 2048;
+    esp_modem_dce_config_t dce_config = ESP_MODEM_DCE_DEFAULT_CONFIG("internet23");
+    dce_config.populate_command_list = true;
+    esp_netif_config_t ppp_netif_config = ESP_NETIF_DEFAULT_PPP();
+
+
+    // Initialize esp-modem units, DTE, DCE, ppp-netif
+    esp_modem_dte_t *dte = esp_modem_dte_new(&dte_config);
+    esp_modem_dce_t *dce = sim7600_board_create(&dce_config);
+    esp_netif_t *ppp_netif = esp_netif_new(&ppp_netif_config);
+
+    assert(ppp_netif);
+
+    ESP_ERROR_CHECK(esp_modem_set_event_handler(dte, on_modem_event, ESP_EVENT_ANY_ID, dte));
+    ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, ESP_EVENT_ANY_ID, on_modem_event, dte));
+
+    ESP_ERROR_CHECK(esp_modem_default_attach(dte, dce, ppp_netif));
+
+    ESP_ERROR_CHECK(esp_modem_default_start(dte)); // use retry
+    ESP_ERROR_CHECK(esp_modem_start_ppp(dte));
+    /* Wait for the first connection */
+    EventBits_t bits;
+    do {
+        bits = xEventGroupWaitBits(event_group, (CONNECT_BIT | DISCONNECT_BIT), pdTRUE, pdFALSE, portMAX_DELAY);
+        if (bits&DISCONNECT_BIT) {
+        }
+    } while ((bits&CONNECT_BIT) == 0);
+
+    /* Init the AP with NAT enabled */
+    esp_netif_t *ap_netif = esp_netif_create_default_wifi_ap();
+    assert(ap_netif);
+    esp_netif_dns_info_t dns;
+    ESP_ERROR_CHECK(esp_netif_get_dns_info(ppp_netif, ESP_NETIF_DNS_MAIN, &dns));
+    set_dhcps_dns(ap_netif, dns.ip.u_addr.ip4.addr);
+
+    wifi_init_softap();
+    ip_napt_enable(_g_esp_netif_soft_ap_ip.ip.addr, 1);
+
+    /* Provide recovery if disconnection of some kind registered */
+    while (DISCONNECT_BIT&xEventGroupWaitBits(event_group, DISCONNECT_BIT, pdTRUE, pdFALSE, portMAX_DELAY)) {
+        // restart the modem PPP mode
+        ESP_ERROR_CHECK(esp_modem_stop_ppp(dte));
+        ESP_ERROR_CHECK(esp_modem_start_ppp(dte));
+    }
+
+}

esp_modem/examples/ap_to_pppos/main/component.mk

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+#
+# Main component makefile.
+#
+# This Makefile can be left empty. By default, it will take the sources in the 
+# src/ directory, compile them and link them into lib(subdirectory_name).a 
+# in the build directory. This behaviour is entirely configurable,
+# please read the ESP-IDF documents if you need to do this.
+#

esp_modem/examples/ap_to_pppos/main/idf_component.yml

@@ -0,0 +1,7 @@
+version: "0.0.2"
+targets:
+  - esp32
+description: pppos_client to AP
+dependencies:
+  espressif/esp_modem:
+    version: "~0.0.2"

esp_modem/examples/ap_to_pppos/main/modem_board.c

@@ -0,0 +1,162 @@
+/*  softAP to PPPoS Example (modem_board)
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+#include <stdlib.h>
+#include <string.h>
+#include "esp_log.h"
+#include "esp_modem_recov_helper.h"
+#include "esp_modem_dce.h"
+#include "esp_modem_dce_common_commands.h"
+
+#define ESP_MODEM_EXAMPLE_CHECK(a, str, goto_tag, ...)                                \
+    do                                                                                \
+    {                                                                                 \
+        if (!(a))                                                                     \
+        {                                                                             \
+            ESP_LOGE(TAG, "%s(%d): " str, __FUNCTION__, __LINE__, ##__VA_ARGS__); \
+            goto goto_tag;                                                            \
+        }                                                                             \
+    } while (0)
+
+
+static const char *TAG = "sim7600_board";
+
+typedef struct {
+    esp_modem_dce_t parent;
+    esp_modem_recov_gpio_t *power_pin;
+    esp_modem_recov_gpio_t *reset_pin;
+    esp_err_t (*reset)(esp_modem_dce_t *dce);
+    esp_err_t (*power_down)(esp_modem_dce_t *dce);
+    esp_modem_recov_resend_t *re_sync;
+    esp_modem_recov_resend_t *re_store_profile;
+} sim7600_board_t;
+
+esp_err_t sim7600_board_handle_powerup(esp_modem_dce_t *dce, const char *line)
+{
+    if (strstr(line, "PB DONE")) {
+        ESP_LOGI(TAG, "Board ready after hard reset/power-cycle");
+    }
+    return ESP_OK;
+}
+
+esp_err_t sim7600_board_deinit(esp_modem_dce_t *dce)
+{
+    sim7600_board_t *board = __containerof(dce, sim7600_board_t, parent);
+    board->power_pin->destroy(board->power_pin);
+    board->power_pin->destroy(board->reset_pin);
+    esp_err_t err = esp_modem_command_list_deinit(&board->parent);
+    if (err == ESP_OK) {
+        free(dce);
+    }
+    return err;
+}
+
+esp_err_t sim7600_board_reset(esp_modem_dce_t *dce)
+{
+    sim7600_board_t *board = __containerof(dce, sim7600_board_t, parent);
+    ESP_LOGI(TAG, "sim7600_board_reset!");
+    dce->handle_line = sim7600_board_handle_powerup;
+    board->power_pin->pulse(board->reset_pin);
+    return ESP_OK;
+}
+
+esp_err_t sim7600_board_power_up(esp_modem_dce_t *dce)
+{
+    sim7600_board_t *board = __containerof(dce, sim7600_board_t, parent);
+    ESP_LOGI(TAG, "sim7600_board_power_up!");
+    dce->handle_line = sim7600_board_handle_powerup;
+    board->power_pin->pulse(board->power_pin);
+    return ESP_OK;
+}
+
+
+esp_err_t sim7600_board_power_down(esp_modem_dce_t *dce)
+{
+    sim7600_board_t *board = __containerof(dce, sim7600_board_t, parent);
+    ESP_LOGI(TAG, "sim7600_board_power_down!");
+    /* power down sequence (typical values for SIM7600 Toff=min2.5s, Toff-status=26s) */
+    dce->handle_line = sim7600_board_handle_powerup;
+    board->power_pin->pulse_special(board->power_pin, 3000, 26000);
+    return ESP_OK;
+}
+
+static esp_err_t my_recov(esp_modem_recov_resend_t *retry_cmd, esp_err_t err, int timeouts, int errors)
+{
+    esp_modem_dce_t *dce = retry_cmd->dce;
+    ESP_LOGI(TAG, "Current timeouts: %d and errors: %d", timeouts, errors);
+    if (err == ESP_ERR_TIMEOUT) {
+        if (timeouts < 2) {
+            // first timeout, try to exit data mode and sync again
+            dce->set_command_mode(dce, NULL, NULL);
+            esp_modem_dce_sync(dce, NULL, NULL);
+        } else if (timeouts < 3) {
+            // try to reset with GPIO if resend didn't help
+            sim7600_board_t *board = __containerof(dce, sim7600_board_t, parent);
+            board->reset(dce);
+        } else {
+            // otherwise power-cycle the board
+            sim7600_board_t *board = __containerof(dce, sim7600_board_t, parent);
+            board->power_down(dce);
+            esp_modem_dce_sync(dce, NULL, NULL);
+        }
+    } else {
+        // check if a PIN needs to be supplied in case of a failure
+        bool ready = false;
+        esp_modem_dce_read_pin(dce, NULL, &ready);
+        if (!ready) {
+            esp_modem_dce_set_pin(dce, "1234", NULL);
+        }
+        vTaskDelay(1000 / portTICK_RATE_MS);
+        esp_modem_dce_read_pin(dce, NULL, &ready);
+        if (!ready) {
+            return ESP_FAIL;
+        }
+    }
+    return ESP_OK;
+}
+
+static DEFINE_RETRY_CMD(re_sync_fn, re_sync, sim7600_board_t)
+
+static DEFINE_RETRY_CMD(re_store_profile_fn, re_store_profile, sim7600_board_t)
+
+esp_err_t sim7600_board_start_up(esp_modem_dce_t *dce)
+{
+//    sim7600_board_t *board = __containerof(dce, sim7600_board_t, parent);
+    ESP_MODEM_EXAMPLE_CHECK(re_sync_fn(dce, NULL, NULL) == ESP_OK, "sending sync failed", err);
+    ESP_MODEM_EXAMPLE_CHECK(dce->set_echo(dce, (void*)false, NULL) == ESP_OK, "set_echo failed", err);
+    ESP_MODEM_EXAMPLE_CHECK(dce->set_flow_ctrl(dce, (void*)ESP_MODEM_FLOW_CONTROL_NONE, NULL) == ESP_OK, "set_flow_ctrl failed", err);
+    ESP_MODEM_EXAMPLE_CHECK(dce->store_profile(dce, NULL, NULL) == ESP_OK, "store_profile failed", err);
+    return ESP_OK;
+err:
+    return ESP_FAIL;
+
+}
+
+esp_modem_dce_t *sim7600_board_create(esp_modem_dce_config_t *config)
+{
+    sim7600_board_t *board = calloc(1, sizeof(sim7600_board_t));
+    ESP_MODEM_EXAMPLE_CHECK(board, "failed to allocate board-sim7600 object", err);
+    ESP_MODEM_EXAMPLE_CHECK(esp_modem_dce_init(&board->parent, config) == ESP_OK, "Failed to init sim7600", err);
+    /* power on sequence (typical values for SIM7600 Ton=500ms, Ton-status=16s) */
+    board->power_pin = esp_modem_recov_gpio_new( /*gpio_num*/ 12, /*inactive_level*/ 1, /*active_width*/
+                                                              500, /*inactive_width*/ 16000);
+    /* reset sequence (typical values for SIM7600 Treset=200ms, wait 10s after reset */
+    board->reset_pin = esp_modem_recov_gpio_new( /*gpio_num*/ 13, /*inactive_level*/ 1, /*active_width*/
+                                                              200, /*inactive_width*/ 10000);
+    board->parent.deinit = sim7600_board_deinit;
+    board->reset = sim7600_board_reset;
+    board->power_down = sim7600_board_power_down;
+    board->re_sync = esp_modem_recov_resend_new(&board->parent, board->parent.sync, my_recov, 5, 1);
+    board->parent.start_up = sim7600_board_start_up;
+    board->re_store_profile = esp_modem_recov_resend_new(&board->parent, board->parent.store_profile, my_recov, 2, 3);
+    board->parent.store_profile = re_store_profile_fn;
+
+    return &board->parent;
+err:
+    return NULL;
+}

esp_modem/examples/ap_to_pppos/sdkconfig.defaults

@@ -0,0 +1,12 @@
+# Override some defaults to enable PPP
+CONFIG_LWIP_PPP_SUPPORT=y
+CONFIG_LWIP_PPP_PAP_SUPPORT=y
+CONFIG_LWIP_TCPIP_TASK_STACK_SIZE=4096
+# Do not enable IPV6 in dte<->dce link local
+CONFIG_LWIP_PPP_ENABLE_IPV6=n
+# Disable legacy API
+CONFIG_MODEM_LEGACY_API=n
+# Enable NAPT
+CONFIG_LWIP_IP_FORWARD=y
+CONFIG_LWIP_IPV4_NAPT=y
+