esp_modem: Moved to component folder

components/esp_modem/examples/linux_modem/CMakeLists.txt

@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.5)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+set(EXTRA_COMPONENT_DIRS ../.. ../../port/linux)
+
+set(COMPONENTS main)
+project(linux_modem)
+
+
+idf_component_get_property(esp_modem esp_modem COMPONENT_LIB)
+target_compile_definitions(${esp_modem} PRIVATE "-DCONFIG_COMPILER_CXX_EXCEPTIONS")
+target_compile_definitions(${esp_modem} PRIVATE "-DCONFIG_IDF_TARGET_LINUX")

components/esp_modem/examples/linux_modem/README.md

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+# Linux modem example
+
+This is an experimental port of the esp_modem to linux.
+It mocks some IDF functionality with `port/linux` layers (used for modem host test suite) and implements `esp_netif`,
+which supports `tun` interface and uses lwIP `ppp` implementation to parse or wrap IP packets to be send/receive
+over PPPoS, i.e. over the modem serial line.
+
+## Configuration
+
+* Set path to the lwip and lwip_contrib repositories as environmental variables:
+  - `LWIP_PATH`: path to the lwip repository
+  - `LWIP_CONTRIB_PATH`: path to the lwip_contrib repository
+* Create a `tun` interface using `make_tun_netif` script.
+* Set SIO dev name directly in the code: This is the serial port which is the modem connected to
+* (Set the tun device na interface name in the code: Not needed if the device was created using the script above.)
+* Build and run the example (no elevated privileges needed)
+* Experiment with the network, after getting the IP from the modem device
+    - directly in the code
+    - in the system (need to set `tun` interface IP, dns servers, and routing the desired traffic over the tun interface)

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

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+idf_component_register(SRCS "modem_main.cpp"
+                       REQUIRES esp_modem)
+
+set(THREADS_PREFER_PTHREAD_FLAG ON)
+find_package(Threads REQUIRED)
+target_link_libraries(${COMPONENT_LIB}  PRIVATE Threads::Threads)
+
+target_compile_features(${COMPONENT_LIB} PRIVATE cxx_std_17)
+target_compile_definitions(${COMPONENT_LIB} PRIVATE "-DCONFIG_IDF_TARGET_LINUX")

components/esp_modem/examples/linux_modem/main/modem_main.cpp

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+#include <memory>
+#include <cassert>
+#include <unistd.h>
+#include <esp_log.h>
+#include "cxx_include/esp_modem_terminal.hpp"
+#include "cxx_include/esp_modem_api.hpp"
+#include "cxx_include/esp_modem_dte.hpp"
+#include "esp_modem_config.h"
+#include "esp_netif.h"
+
+
+#define CONFIG_EXAMPLE_SIM_PIN "1234"
+
+using namespace esp_modem;
+
+[[maybe_unused]] static const char *TAG = "linux_modem_main";
+
+
+int main()
+{
+
+    // init the DTE
+    esp_modem_dte_config_t dte_config = {
+            .dte_buffer_size = 512,
+            .task_stack_size = 1024,
+            .task_priority = 10,
+            .uart_config = { },
+            .vfs_config = { }
+    };
+    dte_config.vfs_config.dev_name = "/dev/ttyUSB0";
+    dte_config.vfs_config.resource = ESP_MODEM_VFS_IS_UART; // This tells the VFS to init the UART (use termux to setup baudrate, etc.)
+
+    esp_netif_config_t netif_config = {
+            .dev_name = "/dev/net/tun",
+            .if_name = "tun0"
+    };
+    esp_netif_t *tun_netif = esp_netif_new(&netif_config);
+    auto uart_dte = create_vfs_dte(&dte_config);
+
+    esp_modem_dce_config_t dce_config = ESP_MODEM_DCE_DEFAULT_CONFIG("internet");
+
+    auto dce = create_SIM7600_dce(&dce_config, uart_dte, tun_netif);
+    assert(dce != nullptr);
+
+    dce->set_command_mode();
+
+    bool pin_ok = true;
+    if (dce->read_pin(pin_ok) == command_result::OK && !pin_ok) {
+        throw_if_false(dce->set_pin(CONFIG_EXAMPLE_SIM_PIN) == command_result::OK, "Cannot set PIN!");
+        usleep(1000000);
+    }
+    std::string str;
+    dce->set_mode(esp_modem::modem_mode::CMUX_MODE);
+    dce->get_imsi(str);
+    ESP_LOGI(TAG, "Modem IMSI number: %s",str.c_str());
+    dce->get_imei(str);
+    ESP_LOGI(TAG, "Modem IMEI number: %s",str.c_str());
+    dce->get_operator_name(str);
+    ESP_LOGI(TAG, "Operator name: %s",str.c_str());
+
+    dce->set_mode(esp_modem::modem_mode::DATA_MODE);
+
+    usleep(100'000'000);
+    esp_netif_destroy(tun_netif);
+}

components/esp_modem/examples/linux_modem/make_tun_netif

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+sudo ip tuntap add mode tun user `whoami`
+sudo ip link set dev tun0 up
+sudo ifconfig tun0 10.184.178.109 netmask 255.255.255.255 up

components/esp_modem/examples/linux_modem/sdkconfig.defaults

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+CONFIG_IDF_TARGET="linux"
+CONFIG_COMPILER_CXX_EXCEPTIONS=y
+CONFIG_COMPILER_CXX_RTTI=y
+CONFIG_COMPILER_CXX_EXCEPTIONS_EMG_POOL_SIZE=0
+CONFIG_COMPILER_STACK_CHECK_NONE=y