Use NTP to synchronize time of internal RTC for usage by OPC/UA server

examples/opcua_server/opcua_server.ino

@@ -4,6 +4,7 @@
 
 #include "PortentaEthernet.h"
 #include "Arduino_open62541.h"
+#include <mbed_rtc_time.h>
 
 #ifndef ARDUINO_OPEN62541_O1HEAP_DEBUG
 # define ARDUINO_OPEN62541_O1HEAP_DEBUG (0) /* Change to (1) if you want to see debug messages on Serial concerning o1heap memory calls. */
@@ -188,6 +189,19 @@ void setup()
     for (;;) { }
   }
 
+  /* Try and obtain the current time via NTP and configure the Arduino
+   * Opta's onboard RTC accordingly. The RTC is then used inside the
+   * open62541 Arduino wrapper to obtain the correct timestamps for
+   * the OPC/UA server.
+   */
+  EthernetUDP udp_client;
+  auto const epoch = opcua::NTPUtils::getTime(udp_client);
+  if (epoch > 0) {
+    set_time(epoch); /* Directly set RTC of Arduino Opta. */
+  } else {
+    set_time(opcua::cvt_time(__DATE__)); /* Configure Arduino Opta with time at compile time as last time of defense. */
+  }
+
   /* Initialize heap memory. */
   o1heap_ins = o1heapInit(OPC_UA_SERVER_THREAD_HEAP.data(), OPC_UA_SERVER_THREAD_HEAP.size());
   if (o1heap_ins == nullptr) {

src/Arduino_open62541.h

@@ -15,6 +15,8 @@
 
 #include "open62541.h"
 #include "o1heap/o1heap.h"
+#include "NTPUtils.h"
+#include "cvt_time.h"
 
 #include "ArduinoOpta.h"
 #include "ArduinoOptaVariant.h"

src/NTPUtils.cpp

@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2024 Arduino
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include "NTPUtils.h"
+
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+namespace opcua
+{
+
+/**************************************************************************************
+ * PUBLIC MEMBER FUNCTIONS
+ **************************************************************************************/
+
+unsigned long NTPUtils::getTime(UDP &udp)
+{
+  udp.begin(NTP_LOCAL_PORT);
+
+  sendNTPpacket(udp);
+
+  bool is_timeout = false;
+  unsigned long const start = millis();
+  do
+  {
+    is_timeout = (millis() - start) >= NTP_TIMEOUT_MS;
+  } while (!is_timeout && !udp.parsePacket());
+
+  if (is_timeout)
+  {
+    udp.stop();
+    return 0;
+  }
+
+  uint8_t ntp_packet_buf[NTP_PACKET_SIZE];
+  udp.read(ntp_packet_buf, NTP_PACKET_SIZE);
+  udp.stop();
+
+  unsigned long const highWord = word(ntp_packet_buf[40], ntp_packet_buf[41]);
+  unsigned long const lowWord = word(ntp_packet_buf[42], ntp_packet_buf[43]);
+  unsigned long const secsSince1900 = highWord << 16 | lowWord;
+  unsigned long const seventyYears = 2208988800UL;
+  unsigned long const epoch = secsSince1900 - seventyYears;
+
+  return epoch;
+}
+
+/**************************************************************************************
+ * PRIVATE MEMBER FUNCTIONS
+ **************************************************************************************/
+
+void NTPUtils::sendNTPpacket(UDP &udp)
+{
+  uint8_t ntp_packet_buf[NTP_PACKET_SIZE] = {0};
+
+  ntp_packet_buf[0] = 0b11100011;
+  ntp_packet_buf[1] = 0;
+  ntp_packet_buf[2] = 6;
+  ntp_packet_buf[3] = 0xEC;
+  ntp_packet_buf[12] = 49;
+  ntp_packet_buf[13] = 0x4E;
+  ntp_packet_buf[14] = 49;
+  ntp_packet_buf[15] = 52;
+
+  udp.beginPacket(NTP_TIME_SERVER, NTP_TIME_SERVER_PORT);
+  udp.write(ntp_packet_buf, NTP_PACKET_SIZE);
+  udp.endPacket();
+}
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+} /* opcua */

src/NTPUtils.h

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2024 Arduino
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+/*
+	This Utility Class is derived from the example code found here https://www.arduino.cc/en/Tutorial/UdpNTPClient
+	For more information on NTP (Network Time Protocol) you can refer to this Wikipedia article https://en.wikipedia.org/wiki/Network_Time_Protocol
+*/
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include <Arduino.h>
+#include <Udp.h>
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+namespace opcua
+{
+
+/**************************************************************************************
+ * CLASS DECLARATION
+ **************************************************************************************/
+
+class NTPUtils
+{
+public:
+
+  static unsigned long getTime(UDP &udp);
+
+private:
+
+  static size_t const NTP_PACKET_SIZE = 48;
+  static int const NTP_TIME_SERVER_PORT = 123;
+  static int const NTP_LOCAL_PORT = 8888;
+
+  static unsigned long const NTP_TIMEOUT_MS = 1000;
+  static constexpr const char *NTP_TIME_SERVER = "time.arduino.cc";
+
+  static void sendNTPpacket(UDP &udp);
+};
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+} /* opcua */

src/arch/posix/ua_clock.cpp

@@ -18,8 +18,11 @@ extern "C" {
 
 int clock_gettime(clockid_t clk_id, struct timespec *tp)
 {
-  tp->tv_sec = millis() / 1000;
-  tp->tv_nsec = (millis() % 1000) * 1000000;
+  /* Obtain time from RTC. */
+  time_t const epoch = time(NULL);
+  /* No nanosecond resolution. */
+  tp->tv_sec = epoch;
+  tp->tv_nsec = 0;
   return 0;
 }
 

src/cvt_time.cpp

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2024 Arduino
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include "cvt_time.h"
+
+#include <stdio.h>
+#include <string.h>
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+namespace opcua
+{
+
+/**************************************************************************************
+ * FUNCTION DEFINITION
+ **************************************************************************************/
+
+time_t cvt_time(char const * time)
+{
+  static time_t build_time = 0;
+
+  if (!build_time) {
+    char s_month[5];
+    int month, day, year;
+    struct tm t =
+      {
+        0 /* tm_sec   */,
+        0 /* tm_min   */,
+        0 /* tm_hour  */,
+        0 /* tm_mday  */,
+        0 /* tm_mon   */,
+        0 /* tm_year  */,
+        0 /* tm_wday  */,
+        0 /* tm_yday  */,
+        0 /* tm_isdst */
+      };
+    static const char month_names[] = "JanFebMarAprMayJunJulAugSepOctNovDec";
+
+    sscanf(time, "%s %d %d", s_month, &day, &year);
+
+    month = (strstr(month_names, s_month) - month_names) / 3;
+
+    t.tm_mon = month;
+    t.tm_mday = day;
+    t.tm_year = year - 1900;
+    t.tm_isdst = -1;
+
+    build_time = mktime(&t);
+  }
+
+  return build_time;
+}
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+} /* opcua */

src/cvt_time.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2024 Arduino
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include <time.h>
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+namespace opcua
+{
+
+/**************************************************************************************
+ * FUNCTION DECLARATION
+ **************************************************************************************/
+
+time_t cvt_time(char const * time);
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+} /* opcua */