New example for ntp_client with LwIP Socket API (#434)

Implemented a new example derived from the existing ntp_client example,
but this time using the LwIP Socket API and FreeRTOS NO_SYS=0.

README.md

@@ -143,6 +143,7 @@ App|Description
 [picow_freertos_iperf_server_sys](pico_w/wifi/freertos/iperf) | Runs an "iperf" server for WiFi speed testing under FreeRTOS in NO_SYS=0 (i.e. full FreeRTOS integration) mode. The LED is blinked in another task
 [picow_freertos_ping_nosys](pico_w/wifi/freertos/ping) | Runs the lwip-contrib/apps/ping test app under FreeRTOS in NO_SYS=1 mode.
 [picow_freertos_ping_sys](pico_w/wifi/freertos/ping) | Runs the lwip-contrib/apps/ping test app under FreeRTOS in NO_SYS=0 (i.e. full FreeRTOS integration) mode. The test app uses the lwIP _socket_ API in this case.
+[picow_freertos_ntp_client_socket](pico_w/wifi/freertos/ntp_client_socket) | Connects to an NTP server using the LwIP Socket API with FreeRTOS in NO_SYS=0 (i.e. full FreeRTOS integration) mode.
 
 ### Pico W Bluetooth
 

pico_w/wifi/freertos/CMakeLists.txt

@@ -5,4 +5,5 @@ else()
 
     add_subdirectory(iperf)
     add_subdirectory(ping)
-endif()
+    add_subdirectory(ntp_client_socket)
+endif()

pico_w/wifi/freertos/ntp_client_socket/CMakeLists.txt

@@ -0,0 +1,20 @@
+add_executable(picow_freertos_ntp_client_socket
+        picow_freertos_ntp_client_socket.c
+        )
+target_compile_definitions(picow_freertos_ntp_client_socket PRIVATE
+        WIFI_SSID=\"${WIFI_SSID}\"
+        WIFI_PASSWORD=\"${WIFI_PASSWORD}\"
+        NO_SYS=0            # don't want NO_SYS (generally this would be in your lwipopts.h)
+        LWIP_SOCKET=1       # we need the socket API (generally this would be in your lwipopts.h)
+        )
+target_include_directories(picow_freertos_ntp_client_socket PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+        ${CMAKE_CURRENT_LIST_DIR}/.. # for our common FreeRTOSConfig
+        ${CMAKE_CURRENT_LIST_DIR}/../.. # for our common lwipopts
+        )
+target_link_libraries(picow_freertos_ntp_client_socket
+        pico_cyw43_arch_lwip_sys_freertos
+        pico_stdlib
+        FreeRTOS-Kernel-Heap4 # FreeRTOS kernel and dynamic heap
+        )
+pico_add_extra_outputs(picow_freertos_ntp_client_socket)

pico_w/wifi/freertos/ntp_client_socket/FreeRTOSConfig.h

@@ -0,0 +1,35 @@
+/*
+ * FreeRTOS V202111.00
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://www.FreeRTOS.org
+ * http://aws.amazon.com/freertos
+ *
+ * 1 tab == 4 spaces!
+ */
+
+#ifndef FREERTOS_CONFIG_H
+#define FREERTOS_CONFIG_H
+
+// This example uses a common include to avoid repetition
+#include "FreeRTOSConfig_examples_common.h"
+
+#endif /* FREERTOS_CONFIG_H */
+

pico_w/wifi/freertos/ntp_client_socket/lwipopts.h

@@ -0,0 +1,25 @@
+#ifndef _LWIPOPTS_H
+#define _LWIPOPTS_H
+
+// Generally you would define your own explicit list of lwIP options
+// (see https://www.nongnu.org/lwip/2_1_x/group__lwip__opts.html)
+//
+// This example uses a common include to avoid repetition
+#include "lwipopts_examples_common.h"
+
+#if !NO_SYS
+#define TCPIP_THREAD_STACKSIZE 1024
+#define DEFAULT_THREAD_STACKSIZE 1024
+#define DEFAULT_RAW_RECVMBOX_SIZE 8
+#define DEFAULT_UDP_RECVMBOX_SIZE 8
+#define DEFAULT_TCP_RECVMBOX_SIZE 8
+#define TCPIP_MBOX_SIZE 8
+#define LWIP_TIMEVAL_PRIVATE 0
+
+// not necessary, can be done either way
+#define LWIP_TCPIP_CORE_LOCKING_INPUT 1
+
+#define LWIP_SO_RCVTIMEO 1
+#endif
+
+#endif

pico_w/wifi/freertos/ntp_client_socket/picow_freertos_ntp_client_socket.c

@@ -0,0 +1,189 @@
+/**
+ * Copyright (c) 2022 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "pico/cyw43_arch.h"
+#include "pico/stdlib.h"
+
+#include "lwip/ip4_addr.h"
+#include "lwip/dns.h"
+#include "lwip/pbuf.h"
+#include "lwip/udp.h"
+#include "lwip/sockets.h"
+#include "lwip/netdb.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+
+#ifndef RUN_FREERTOS_ON_CORE
+#define RUN_FREERTOS_ON_CORE 0
+#endif
+
+#define TEST_TASK_PRIORITY                ( tskIDLE_PRIORITY + 1UL )
+
+#define NTP_SERVER ("pool.ntp.org")
+#define NTP_MSG_LEN (48)
+#define NTP_PORT (123)
+// seconds between 1 Jan 1900 and 1 Jan 1970
+#define NTP_DELTA (2208988800)
+#define ntpEST_TIME (30 * 1000)
+#define NTP_FAIL_TIME (10)
+
+void main_task(__unused void *params) {
+    if (cyw43_arch_init()) {
+        printf("failed to initialise\n");
+        vTaskDelete(NULL);
+    }
+    cyw43_arch_enable_sta_mode();
+    printf("Connecting to Wi-Fi...\n");
+    if (cyw43_arch_wifi_connect_timeout_ms(WIFI_SSID, WIFI_PASSWORD, CYW43_AUTH_WPA2_AES_PSK, 30000)) {
+        printf("failed to connect.\n");
+        vTaskDelete(NULL);
+    } else {
+        printf("Connected.\n");
+    }
+
+    while(true) {
+        const struct addrinfo ntp_info = {
+            .ai_flags = 0,
+            .ai_family = AF_UNSPEC,
+            .ai_socktype = SOCK_DGRAM,
+            .ai_protocol = 0,
+        };
+
+        struct addrinfo *dns_result = NULL;
+        printf("Trying DNS...\n");
+        int err = getaddrinfo(NTP_SERVER, "123", &ntp_info, &dns_result);
+        if (err != 0)
+        {
+            printf("DNS lookup failed with error: %d\n", err);
+            continue;
+        }
+#ifndef INET6_ADDRSTRLEN
+        char address[INET_ADDRSTRLEN] = {0};
+#else
+        char address[INET6_ADDRSTRLEN] = {0};
+#endif
+        ip_addr_t ip_addr;
+#if LWIP_IPV4
+        if (dns_result->ai_addr->sa_family == AF_INET) {
+            const struct sockaddr_in *sock_addr = (struct sockaddr_in*)dns_result->ai_addr;
+            inet_addr_to_ip4addr(ip_2_ip4(&ip_addr), &sock_addr->sin_addr);
+            IP_SET_TYPE(&ip_addr, IPADDR_TYPE_V4);
+        }
+#endif
+#if LWIP_IPV6
+        if (dns_result->ai_addr->sa_family == AF_INET6) {
+            const struct sockaddr_in6 *sock_addr = (struct sockaddr_in6*)dns_result->ai_addr;
+            inet6_addr_to_ip6addr(ip_2_ip6(&ip_addr), &sock_addr->sin6_addr);
+            IP_SET_TYPE(&ip_addr, IPADDR_TYPE_V6);
+        }
+#endif
+        inet_ntop(dns_result->ai_family, &ip_addr, address, sizeof(address));
+        printf("Got DNS response: %s\n", address);
+
+        int sock = socket(dns_result->ai_family, dns_result->ai_socktype, dns_result->ai_protocol);
+        if (sock == -1)
+        {
+            printf("Failed to allocate socket");
+            freeaddrinfo(dns_result);
+            continue;
+        }
+
+        struct timeval timeout = {
+            .tv_sec = NTP_FAIL_TIME,
+        };
+        setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout));
+        err = connect(sock, dns_result->ai_addr, dns_result->ai_addrlen);
+        freeaddrinfo(dns_result);
+        if (err == -1)
+        {
+            printf("Failed to connect to NTP server");
+            close(sock);
+            continue;
+        }
+
+        unsigned char request[NTP_MSG_LEN] = {0x1b, 0};
+        int amount = send(sock, request, NTP_MSG_LEN, 0);
+        if (amount != NTP_MSG_LEN)
+        {
+            printf("We were unable to send the complete NTP request");
+            close(sock);
+            continue;
+        }
+
+        amount = recv(sock, request, NTP_MSG_LEN, 0);
+        close(sock);
+        if (amount != NTP_MSG_LEN)
+        {
+            printf("We did not receive a complete NTP response");
+            continue;
+        }
+
+        uint8_t mode = request[0] & 0x7;
+        uint8_t stratum = request[1];
+
+        // Check the result
+        if (amount == NTP_MSG_LEN &&
+            mode == 0x4 &&
+            stratum != 0)
+        {
+            uint8_t seconds_buf[4] = {};
+            memcpy(seconds_buf, request + 40, 4);
+            uint32_t seconds_since_1900 = seconds_buf[0] << 24 | seconds_buf[1] << 16 | seconds_buf[2] << 8 | seconds_buf[3];
+            uint32_t seconds_since_1970 = seconds_since_1900 - NTP_DELTA;
+            time_t epoch = seconds_since_1970;
+            struct tm *utc = gmtime(&epoch);
+            printf("got ntp response: %02d/%02d/%04d %02d:%02d:%02d\n", utc->tm_mday, utc->tm_mon + 1, utc->tm_year + 1900,
+                   utc->tm_hour, utc->tm_min, utc->tm_sec);
+        }
+
+        // This assumes one tick is one ms, which is true for the default configuration
+        vTaskDelay(ntpEST_TIME);
+    }
+
+    cyw43_arch_deinit();
+}
+
+void vLaunch( void) {
+    TaskHandle_t task;
+    xTaskCreate(main_task, "TestMainThread", 4096, NULL, TEST_TASK_PRIORITY, &task);
+
+#if NO_SYS && configUSE_CORE_AFFINITY && configNUM_CORES > 1
+    // we must bind the main task to one core (well at least while the init is called)
+    // (note we only do this in NO_SYS mode, because cyw43_arch_freertos
+    // takes care of it otherwise)
+    vTaskCoreAffinitySet(task, 1);
+#endif
+
+    /* Start the tasks and timer running. */
+    vTaskStartScheduler();
+}
+
+int main( void )
+{
+    stdio_init_all();
+
+    /* Configure the hardware ready to run the demo. */
+    const char *rtos_name;
+#if ( portSUPPORT_SMP == 1 )
+    rtos_name = "FreeRTOS SMP";
+#else
+    rtos_name = "FreeRTOS";
+#endif
+
+#if ( portSUPPORT_SMP == 1 ) && ( configNUM_CORES == 2 )
+    printf("Starting %s on both cores:\n", rtos_name);
+    vLaunch();
+#elif ( RUN_FREERTOS_ON_CORE == 1 )
+    printf("Starting %s on core 1:\n", rtos_name);
+    multicore_launch_core1(vLaunch);
+    while (true);
+#else
+    printf("Starting %s on core 0:\n", rtos_name);
+    vLaunch();
+#endif
+    return 0;
+}