esp-netif: Added esp_netif slip support, slip_modem component and example

Merges https://github.com/espressif/esp-idf/pull/4985


* Original commit: espressif/esp-idf@266be00254

examples/protocols/slip/slip_udp/main/CMakeLists.txt

@@ -0,0 +1,7 @@
+# Slip client example
+
+idf_component_register(
+    SRCS "slip_client_main.c"
+    INCLUDE_DIRS "."
+    REQUIRES esp_netif slip_modem
+)

examples/protocols/slip/slip_udp/main/Kconfig.projbuild

@@ -0,0 +1,32 @@
+menu "Example Configuration"
+
+    menu "UART Configuration"
+        config EXAMPLE_UART_TX_PIN
+            int "TXD Pin Number"
+            default 4
+            range 0 36
+            help
+                Pin number of UART TX.
+
+        config EXAMPLE_UART_RX_PIN
+            int "RXD Pin Number"
+            default 36
+            range 0 36
+            help
+                Pin number of UART RX.
+
+        config EXAMPLE_UART_BAUD
+            int "UART baud rate"
+            default 115200
+            help
+                Baud rate for UART communication
+
+        config EXAMPLE_UDP_PORT
+            int "Port for UDP echo server"
+            default 5678
+            help
+                Port for UDP echo server in example   
+
+    endmenu
+
+endmenu

examples/protocols/slip/slip_udp/main/component.mk

@@ -0,0 +1,4 @@
+#
+# "main" pseudo-component makefile.
+#
+# (Uses default behaviour of compiling all source files in directory, adding 'include' to include path.)

examples/protocols/slip/slip_udp/main/slip_client_main.c

@@ -0,0 +1,229 @@
+/* SLIP Client 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 "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/event_groups.h"
+
+
+#include "esp_system.h"
+#include "esp_log.h"
+#include "esp_event.h"
+#include "esp_netif.h"
+#include "esp_netif_slip.h"
+
+#include "lwip/sockets.h"
+#include "lwip/dns.h"
+#include "lwip/netdb.h"
+
+#include "slip_modem.h"
+
+static const char *TAG = "SLIP_EXAMPLE";
+
+#define STACK_SIZE (10 * 1024)
+#define PRIORITY   10
+
+TaskHandle_t udp_rx_tx_handle;
+
+static void udp_rx_tx_task(void *arg)
+{
+    char addr_str[128];
+    uint8_t rx_buff[1024];
+
+    int sock = *(int *)arg;
+
+    struct sockaddr_in6 source_addr;
+    socklen_t socklen = sizeof(source_addr);
+
+
+    ESP_LOGI(TAG, "Starting node manager UDP task");
+
+    while (1) {
+        // Receive data
+        int len = recvfrom(sock, rx_buff, sizeof(rx_buff) - 1, 0, (struct sockaddr *)&source_addr, &socklen);
+        if (len < 0) {
+            ESP_LOGE(TAG, "recvfrom failed: errno %d", errno);
+            break;
+        }
+
+        // Parse out address to string
+        inet6_ntoa_r(source_addr.sin6_addr, addr_str, sizeof(addr_str) - 1);
+
+        // Force null termination of received data and print
+        rx_buff[len] = 0;
+        ESP_LOGI(TAG, "Received '%s' from '%s'", rx_buff, addr_str);
+
+        // Send data back
+        int err = sendto(sock, rx_buff, len, 0, (struct sockaddr *)&source_addr, socklen);
+        if (err < 0) {
+            ESP_LOGE(TAG, "sendto failed: errno %d", errno);
+            break;
+        }
+    }
+
+    vTaskDelete(NULL);
+}
+
+esp_err_t udp_rx_tx_init()
+{
+    // Setup bind address
+    struct sockaddr_in6 dest_addr;
+    bzero(&dest_addr.sin6_addr.un, sizeof(dest_addr.sin6_addr.un));
+    dest_addr.sin6_family = AF_INET6;
+    dest_addr.sin6_port = htons(CONFIG_EXAMPLE_UDP_PORT);
+
+    // Create socket
+    int sock = socket(AF_INET6, SOCK_DGRAM, IPPROTO_IPV6);
+    if (sock < 0) {
+        ESP_LOGE(TAG, "Unable to create socket: errno %d", errno);
+        return -1;
+    }
+
+    // Disable IPv4 and reuse address
+    int opt = 1;
+    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+    setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &opt, sizeof(opt));
+
+    // Bind socket
+    int err = bind(sock, (struct sockaddr *)&dest_addr, sizeof(dest_addr));
+    if (err < 0) {
+        ESP_LOGE(TAG, "Socket unable to bind: errno %d", errno);
+        return -2;
+    }
+    ESP_LOGI(TAG, "Socket bound, port %d", CONFIG_EXAMPLE_UDP_PORT);
+
+
+    // Start UDP rx thread
+    xTaskCreate(udp_rx_tx_task, "udp_rx_tx", STACK_SIZE, &sock, PRIORITY, &udp_rx_tx_handle);
+
+    return ESP_OK;
+}
+
+// Write a prefix to the contiki slip device
+static void slip_set_prefix(esp_netif_t *slip_netif)
+{
+    uint8_t buff[10] = {0};
+
+    // Fetch the slip interface IP
+    const ip6_addr_t *addr = esp_slip_get_ip6(slip_netif);
+
+    ESP_LOGI(TAG, "%s: prefix set (%08x:%08x)", __func__,
+             lwip_ntohl(addr->addr[0]), lwip_ntohl(addr->addr[1]));
+
+    // Build slip set message
+    buff[0] = '!';
+    buff[1] = 'P';
+    for (int i = 0; i < 2; i++) {
+        for (int j = 0; j < 4; j++) {
+            buff[2 + i * 4 + j] = addr->addr[i] >> (j * 8);
+        }
+    }
+
+    // Write raw data out the slip interface
+    esp_netif_lwip_slip_raw_output(slip_netif, buff, 2 + 8);
+}
+
+// slip_rx_filter filters incomming commands from the slip interface
+// this implementation is designed for use with contiki slip devices
+bool slip_rx_filter(void *ctx, uint8_t *data, uint32_t len)
+{
+
+    esp_netif_t *slip_netif = (esp_netif_t *)ctx;
+
+    if (data[1] == '?') {
+        switch (data[2]) {
+        case 'P':
+            ESP_LOGI(TAG, "Prefix request");
+            slip_set_prefix(slip_netif);
+
+            return true;
+
+        default:
+            ESP_LOGI(TAG, "Unhandled request '%c'", data[2]);
+            break;
+        }
+
+        return true;
+
+    } else if (data[1] == '!') {
+        switch (data[2]) {
+        default:
+            ESP_LOGI(TAG, "Unhandled command '%c'", data[2]);
+            break;
+        }
+    }
+
+    return false;
+}
+
+// Initialise the SLIP interface
+esp_netif_t *slip_if_init()
+{
+    ESP_LOGI(TAG, "Initialising SLIP interface");
+
+    esp_netif_config_t cfg = ESP_NETIF_DEFAULT_SLIP();
+    esp_netif_t *slip_netif = esp_netif_new(&cfg);
+
+    esp_netif_slip_config_t slip_config = {
+        .uart_dev = UART_NUM_2,
+    };
+
+    IP6_ADDR(&slip_config.addr,
+             lwip_htonl(0xfd000000),
+             lwip_htonl(0x00000000),
+             lwip_htonl(0x00000000),
+             lwip_htonl(0x000000001)
+            );
+
+    esp_netif_slip_set_params(slip_netif, &slip_config);
+
+    ESP_LOGI(TAG, "Initialising SLIP modem");
+
+    esp_slip_modem_config_t modem_cfg = {
+        .uart_dev = UART_NUM_2,
+
+        .uart_tx_pin = CONFIG_EXAMPLE_UART_TX_PIN,
+        .uart_rx_pin = CONFIG_EXAMPLE_UART_RX_PIN,
+        .uart_baud = CONFIG_EXAMPLE_UART_BAUD,
+
+        .rx_buffer_len = 1024,
+
+        .rx_filter = slip_rx_filter,
+        .rx_filter_ctx = slip_netif,
+    };
+
+    void *slip_modem = esp_slip_modem_create(slip_netif, &modem_cfg);
+    ESP_ERROR_CHECK(esp_netif_attach(slip_netif, slip_modem));
+
+    ESP_LOGI(TAG, "SLIP init complete");
+
+    return slip_netif;
+}
+
+void app_main(void)
+{
+    // Setup networking
+    tcpip_adapter_init();
+
+    esp_log_level_set("*", ESP_LOG_DEBUG);
+
+    // Create event loop
+    ESP_ERROR_CHECK(esp_event_loop_create_default());
+
+    // Setup slip interface
+    slip_if_init();
+
+    // Setup UDP loopback service
+    udp_rx_tx_init();
+
+    // Run
+    while (1) {
+        vTaskDelay(portTICK_PERIOD_MS * 10);
+    }
+}