[modem]: tcp-client example to support multiple connections

components/esp_modem/examples/modem_tcp_client/main/CMakeLists.txt

@@ -1,7 +1,11 @@
+set(module_dir "generic_module")
 if (CONFIG_EXAMPLE_MODEM_DEVICE_BG96)
     set(device_srcs sock_commands_bg96.cpp)
 elseif(CONFIG_EXAMPLE_MODEM_DEVICE_SIM7600)
     set(device_srcs sock_commands_sim7600.cpp)
+elseif(CONFIG_EXAMPLE_MODEM_DEVICE_ESPAT)
+    set(device_srcs sock_commands_espat.cpp)
+    set(module_dir "espat_module")
 endif()
 
 if(CONFIG_ESP_MODEM_ENABLE_DEVELOPMENT_MODE)
@@ -14,4 +18,4 @@ idf_component_register(SRCS "modem_client.cpp"
                             "${command_dir}/sock_dce.cpp"
                             "tcp_transport_at.cpp"
                             "${device_srcs}"
-                       INCLUDE_DIRS "." "${command_dir}")
+                       INCLUDE_DIRS "." "${command_dir}" "${module_dir}")

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

@@ -18,8 +18,26 @@ menu "Example Configuration"
             bool "SIM7600"
             help
                 SIM7600 is Multi-Band LTE-TDD/LTE-FDD/HSPA+ and GSM/GPRS/EDGE module
+        config EXAMPLE_MODEM_DEVICE_ESPAT
+            bool "ESP-AT"
+            help
+                ESP-AT firmware for ESP32 modules with WiFi connectivity
     endchoice
 
+    if EXAMPLE_MODEM_DEVICE_ESPAT
+        config EXAMPLE_WIFI_SSID
+            string "WiFi SSID"
+            default "myssid"
+            help
+                SSID (network name) to connect to.
+
+        config EXAMPLE_WIFI_PASSWORD
+            string "WiFi Password"
+            default "mypassword"
+            help
+                WiFi password (WPA or WPA2).
+    endif
+
     config EXAMPLE_MODEM_APN
         string "Set MODEM APN"
         default "internet"

components/esp_modem/examples/modem_tcp_client/main/command/sock_dce.cpp

@@ -6,6 +6,7 @@
 
 #include <charconv>
 #include <sys/socket.h>
+#include <algorithm>  // for std::find
 #include "esp_vfs.h"
 #include "esp_vfs_eventfd.h"
 
@@ -15,6 +16,25 @@ namespace sock_dce {
 
 constexpr auto const *TAG = "sock_dce";
 
+// Definition of the static member variables
+std::vector<DCE*> DCE::dce_list{};
+bool DCE::network_init = false;
+
+// Constructor - add this DCE instance to the static list
+DCE::DCE(std::shared_ptr<esp_modem::DTE> dte_arg, const esp_modem_dce_config *config)
+    : Module(std::move(dte_arg), config)
+{
+    dce_list.push_back(this);
+}
+
+// Destructor - remove this DCE instance from the static list
+DCE::~DCE()
+{
+    auto it = std::find(dce_list.begin(), dce_list.end(), this);
+    if (it != dce_list.end()) {
+        dce_list.erase(it);
+    }
+}
 
 bool DCE::perform_sock()
 {
@@ -104,6 +124,7 @@ void DCE::close_sock()
         close(sock);
         sock = -1;
     }
+    close(data_ready_fd);
     dte->on_read(nullptr);
     const int retries = 5;
     int i = 0;
@@ -224,15 +245,18 @@ void DCE::start_listening(int port)
 
 bool DCE::connect(std::string host, int port)
 {
+    data_ready_fd = eventfd(0, EFD_SUPPORT_ISR);
+    assert(data_ready_fd > 0);
     dte->on_read(nullptr);
     tcp_close();
     dte->on_read([this](uint8_t *data, size_t len) {
-        this->perform_at(data, len);
+        read_callback(data, len);
         return esp_modem::command_result::TIMEOUT;
     });
     if (!at.start_connecting(host, port)) {
         ESP_LOGE(TAG, "Unable to start connecting");
         dte->on_read(nullptr);
+        close(data_ready_fd);
         return false;
     }
     state = status::CONNECTING;
@@ -241,12 +265,13 @@ bool DCE::connect(std::string host, int port)
 
 bool DCE::init()
 {
+    if (network_init) {
+        return true;
+    }
+    network_init = true;
     esp_vfs_eventfd_config_t config = ESP_VFS_EVENTD_CONFIG_DEFAULT();
     esp_vfs_eventfd_register(&config);
 
-    data_ready_fd = eventfd(0, EFD_SUPPORT_ISR);
-    assert(data_ready_fd > 0);
-
     dte->on_read(nullptr);
     const int retries = 5;
     int i = 0;

components/esp_modem/examples/modem_tcp_client/main/command/sock_dce.hpp

@@ -8,6 +8,7 @@
 #include "cxx_include/esp_modem_api.hpp"
 #include <cxx_include/esp_modem_dce_factory.hpp>
 #include "sock_commands.hpp"
+#include "sock_module.hpp"
 #include <sys/socket.h>
 
 #pragma  once
@@ -97,9 +98,15 @@ class Responder {
     std::shared_ptr<esp_modem::DTE> &dte;
 };
 
-class DCE : public ::esp_modem::GenericModule {
-    using esp_modem::GenericModule::GenericModule;
+class DCE : public Module {
 public:
+    // Constructor and destructor for managing dce_list
+    // explicit GenericModule(std::shared_ptr<DTE> dte, std::unique_ptr<PdpContext> pdp):
+    //     dte(std::move(dte)), pdp(std::move(pdp)) {}
+    // explicit GenericModule(std::shared_ptr<DTE> dte, );
+    //
+    DCE(std::shared_ptr<esp_modem::DTE> dte_arg, const esp_modem_dce_config *config);
+    ~DCE();
 
     /**
      * @brief Opens network in AT command mode
@@ -236,6 +243,15 @@ class DCE : public ::esp_modem::GenericModule {
     int sock {-1};
     int listen_sock {-1};
     int data_ready_fd {-1};
+    static std::vector<DCE*> dce_list;
+    static bool network_init;
+    static void read_callback(uint8_t *data, size_t len)
+    {
+        for (auto dce : dce_list) {
+            dce->perform_at(data, len);
+        }
+    }
+
 };
 std::unique_ptr<DCE> create(const esp_modem::dce_config *config, std::shared_ptr<esp_modem::DTE> dte);
 }

components/esp_modem/examples/modem_tcp_client/main/espat_module/sock_module.hpp

@@ -0,0 +1,24 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "esp_modem_config.h"
+#include "cxx_include/esp_modem_api.hpp"
+
+#pragma  once
+
+namespace sock_dce {
+
+class Module: public esp_modem::GenericModule {
+    using esp_modem::GenericModule::GenericModule;
+public:
+
+    esp_modem::command_result sync() override;
+    esp_modem::command_result set_echo(bool on) override;
+    esp_modem::command_result set_pdp_context(esp_modem::PdpContext &pdp) override;
+
+};
+
+}

components/esp_modem/examples/modem_tcp_client/main/generate/sock_dce.cpp

@@ -15,6 +15,28 @@ namespace sock_dce {
 
 constexpr auto const *TAG = "sock_dce";
 
+// Definition of the static member variables
+std::vector<DCE*> DCE::dce_list{};
+bool DCE::network_init = false;
+int Responder::s_link_id = 0;
+SemaphoreHandle_t Responder::s_dte_mutex{};
+
+// Constructor - add this DCE instance to the static list
+DCE::DCE(std::shared_ptr<esp_modem::DTE> dte_arg, const esp_modem_dce_config *config)
+    : Module(std::move(dte_arg), config)
+{
+    dce_list.push_back(this);
+}
+
+// Destructor - remove this DCE instance from the static list
+DCE::~DCE()
+{
+    auto it = std::find(dce_list.begin(), dce_list.end(), this);
+    if (it != dce_list.end()) {
+        dce_list.erase(it);
+    }
+}
+
 
 bool DCE::perform_sock()
 {
@@ -61,13 +83,22 @@ bool DCE::perform_sock()
 
 void DCE::perform_at(uint8_t *data, size_t len)
 {
-    ESP_LOG_BUFFER_HEXDUMP(TAG, data, len, ESP_LOG_VERBOSE);
+    std::string_view resp_sv((char *)data, len);
+    at.check_urc(state, resp_sv);
+    if (state == status::IDLE) {
+        return;
+    }
+    ESP_LOG_BUFFER_HEXDUMP(TAG, data, len, ESP_LOG_INFO);
     switch (at.process_data(state, data, len)) {
     case Responder::ret::OK:
+        ESP_LOGW(TAG, "GIVE data %d", at.link_id);
+        xSemaphoreGive(at.s_dte_mutex);
         state = status::IDLE;
         signal.set(IDLE);
         return;
     case Responder::ret::FAIL:
+        ESP_LOGW(TAG, "GIVE data %d", at.link_id);
+        xSemaphoreGive(at.s_dte_mutex);
         state = status::FAILED;
         signal.set(IDLE);
         return;
@@ -82,10 +113,14 @@ void DCE::perform_at(uint8_t *data, size_t len)
     std::string_view response((char *)data, len);
     switch (at.check_async_replies(state, response)) {
     case Responder::ret::OK:
+        ESP_LOGW(TAG, "GIVE command %d", at.link_id);
+        xSemaphoreGive(at.s_dte_mutex);
         state = status::IDLE;
         signal.set(IDLE);
         return;
     case Responder::ret::FAIL:
+        ESP_LOGW(TAG, "GIVE command %d", at.link_id);
+        xSemaphoreGive(at.s_dte_mutex);
         state = status::FAILED;
         signal.set(IDLE);
         return;
@@ -131,6 +166,9 @@ bool DCE::at_to_sock()
         close_sock();
         return false;
     }
+    ESP_LOGI(TAG, "TAKE RECV %d", at.link_id);
+    xSemaphoreTake(at.s_dte_mutex, portMAX_DELAY);
+    ESP_LOGE(TAG, "TAKE RECV %d", at.link_id);
     state = status::RECEIVING;
     at.start_receiving(at.get_buf_len());
     return true;
@@ -139,8 +177,8 @@ bool DCE::at_to_sock()
 bool DCE::sock_to_at()
 {
     ESP_LOGD(TAG,  "socket read: data available");
-    if (!signal.wait(IDLE, 1000)) {
-        ESP_LOGE(TAG,  "Failed to get idle");
+    if (!signal.wait(IDLE, 5000)) {
+        ESP_LOGE(TAG,  "Failed to get idle 2");
         close_sock();
         return false;
     }
@@ -149,6 +187,9 @@ bool DCE::sock_to_at()
         close_sock();
         return false;
     }
+    ESP_LOGI(TAG, "TAKE SEND %d", at.link_id);
+    xSemaphoreTake(at.s_dte_mutex, portMAX_DELAY);
+    ESP_LOGE(TAG, "TAKE SEND %d", at.link_id);
     state = status::SENDING;
     int len = ::recv(sock, at.get_buf(), at.get_buf_len(), 0);
     if (len < 0) {
@@ -224,12 +265,17 @@ void DCE::start_listening(int port)
 
 bool DCE::connect(std::string host, int port)
 {
-    dte->on_read(nullptr);
-    tcp_close();
-    dte->on_read([this](uint8_t *data, size_t len) {
-        this->perform_at(data, len);
-        return esp_modem::command_result::TIMEOUT;
-    });
+    data_ready_fd = eventfd(0, EFD_SUPPORT_ISR);
+    assert(data_ready_fd > 0);
+    // dte->on_read(nullptr);
+    // tcp_close();
+    // dte->on_read([](uint8_t *data, size_t len) {
+    //     read_callback(data, len);
+    //     return esp_modem::command_result::TIMEOUT;
+    // });
+    ESP_LOGI(TAG, "TAKE CONNECT %d", at.link_id);
+    xSemaphoreTake(at.s_dte_mutex, portMAX_DELAY);
+    ESP_LOGE(TAG, "TAKE CONNECT %d", at.link_id);
     if (!at.start_connecting(host, port)) {
         ESP_LOGE(TAG, "Unable to start connecting");
         dte->on_read(nullptr);
@@ -241,12 +287,15 @@ bool DCE::connect(std::string host, int port)
 
 bool DCE::init()
 {
+    if (network_init) {
+        return true;
+    }
+    network_init = true;
+    Responder::s_dte_mutex = xSemaphoreCreateBinary();
+    xSemaphoreGive(at.s_dte_mutex);
     esp_vfs_eventfd_config_t config = ESP_VFS_EVENTD_CONFIG_DEFAULT();
     esp_vfs_eventfd_register(&config);
 
-    data_ready_fd = eventfd(0, EFD_SUPPORT_ISR);
-    assert(data_ready_fd > 0);
-
     dte->on_read(nullptr);
     const int retries = 5;
     int i = 0;
@@ -287,6 +336,10 @@ bool DCE::init()
         esp_modem::Task::Delay(5000);
     }
     ESP_LOGI(TAG, "Got IP %s", ip_addr.c_str());
+    dte->on_read([](uint8_t *data, size_t len) {
+        read_callback(data, len);
+        return esp_modem::command_result::TIMEOUT;
+    });
     return true;
 }