NTPClient.cpp

/**
 * The MIT License (MIT)
 * Copyright (c) 2015 by Fabrice Weinberg
 *
 * 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.
 */

#include "NTPClient.h"

NTPClient::NTPClient(UDP& udp) {
  this->_udp            = &udp;
}

NTPClient::NTPClient(UDP& udp, long timeOffset) {
  this->_udp            = &udp;
  this->_timeOffset     = timeOffset;
}

NTPClient::NTPClient(UDP& udp, const char* poolServerName) {
  this->_udp            = &udp;
  this->_poolServerName = poolServerName;
}

NTPClient::NTPClient(UDP& udp, IPAddress poolServerIP) {
  this->_udp            = &udp;
  this->_poolServerIP   = poolServerIP;
  this->_poolServerName = NULL;
}

NTPClient::NTPClient(UDP& udp, const char* poolServerName, long timeOffset) {
  this->_udp            = &udp;
  this->_timeOffset     = timeOffset;
  this->_poolServerName = poolServerName;
}

NTPClient::NTPClient(UDP& udp, IPAddress poolServerIP, long timeOffset){
  this->_udp            = &udp;
  this->_timeOffset     = timeOffset;
  this->_poolServerIP   = poolServerIP;
  this->_poolServerName = NULL;
}

NTPClient::NTPClient(UDP& udp, const char* poolServerName, long timeOffset, unsigned long updateInterval) {
  this->_udp            = &udp;
  this->_timeOffset     = timeOffset;
  this->_poolServerName = poolServerName;
  this->_updateInterval = updateInterval;
}

NTPClient::NTPClient(UDP& udp, IPAddress poolServerIP, long timeOffset, unsigned long updateInterval) {
  this->_udp            = &udp;
  this->_timeOffset     = timeOffset;
  this->_poolServerIP   = poolServerIP;
  this->_poolServerName = NULL;
  this->_updateInterval = updateInterval;
}

void NTPClient::begin() {
  this->begin(NTP_DEFAULT_LOCAL_PORT);
}

void NTPClient::begin(unsigned int port) {
  this->_port = port;

  this->_udp->begin(this->_port);

  this->_udpSetup = true;
}

bool NTPClient::forceUpdate(unsigned long timeout) {
  this->sendNTPPacket();

  #ifdef DEBUG_NTPClient
    Serial.println("[NTPClient] Waiting for NTP Server response...");
  #endif

  // Wait till data is there or timeout...
  if (this->receiveNTPPacket(timeout)) return true;

  #ifdef DEBUG_NTPClient
    Serial.println("[NTPClient] Timeout");
  #endif
  return false; // timeout 
}

bool NTPClient::needUpdate() {
  if (this->_sendTime == 0) return true;    // Was never updated before.
  if (millis() - this->_sendTime >= this->_updateInterval) return true;    // Previous update was more than configured interval ago.

  return false;
}

bool NTPClient::update(unsigned long timeout) {
  if (this->needUpdate()) {
    return this->forceUpdate(timeout);
  }
  return false;   // return false if update does not occur
}

int NTPClient::asyncUpdate() {
  if (this->needUpdate()) {
    this->sendNTPPacket();

    if (_needUpdate) return -1; // return -1 if timeout
    _needUpdate = true;
    return 2; // return 2 if update is in progress
  }

  if (_needUpdate) {
    if (!this->receiveNTPPacket()) return 2;
    _needUpdate = false;
    return 0;
  }

  return 1;   // return 1 if update does not occur
}

bool NTPClient::isTimeSet() const {
  return (this->_lastUpdate != 0); // returns true if the time has been set, else false
}

long long NTPClient::getEpochTimeMillis() const {
  return (this->_timeOffset + // User offset
          this->_currentEpoch) * 1000LL + // Epoch returned by the NTP server
         (millis() - this->_lastUpdate); // Time since last update
}

unsigned long NTPClient::getEpochTime() const {
  return this->_timeOffset + // User offset
         this->_currentEpoch + // Epoch returned by the NTP server
         ((millis() - this->_lastUpdate) / 1000); // Time since last update
}

int NTPClient::getDay() const {
  return (((this->getEpochTime()  / 86400L) + 4 ) % 7); //0 is Sunday
}
int NTPClient::getHours() const {
  return ((this->getEpochTime()  % 86400L) / 3600);
}
int NTPClient::getMinutes() const {
  return ((this->getEpochTime() % 3600) / 60);
}
int NTPClient::getSeconds() const {
  return (this->getEpochTime() % 60);
}

String NTPClient::getFormattedTime() const {
  unsigned long rawTime = this->getEpochTime();
  unsigned long hours = (rawTime % 86400L) / 3600;
  String hoursStr = hours < 10 ? "0" + String(hours) : String(hours);

  unsigned long minutes = (rawTime % 3600) / 60;
  String minuteStr = minutes < 10 ? "0" + String(minutes) : String(minutes);

  unsigned long seconds = rawTime % 60;
  String secondStr = seconds < 10 ? "0" + String(seconds) : String(seconds);

  return hoursStr + ":" + minuteStr + ":" + secondStr;
}

void NTPClient::end() {
  this->_udp->stop();

  this->_udpSetup = false;
}

void NTPClient::setTimeOffset(int timeOffset) {
  this->_timeOffset     = timeOffset;
}

void NTPClient::setUpdateInterval(unsigned long updateInterval) {
  this->_updateInterval = updateInterval;
}

void NTPClient::setPoolServerName(const char* poolServerName) {
    this->_poolServerName = poolServerName;
}

void NTPClient::sendNTPPacket() {
  if (this->_udpSetup) {
    // flush any existing packets
    while(this->_udp->parsePacket() != 0)
      this->_udp->flush();
  }

  if (!this->_udpSetup) this->begin(this->_port); // setup the UDP client if needed
  // set all bytes in the buffer to 0
  memset(this->_packetBuffer, 0, NTP_PACKET_SIZE);
  // Initialize values needed to form NTP request
  this->_packetBuffer[0] = 0b11100011;   // LI, Version, Mode
  this->_packetBuffer[1] = 0;     // Stratum, or type of clock
  this->_packetBuffer[2] = 6;     // Polling Interval
  this->_packetBuffer[3] = 0xEC;  // Peer Clock Precision
  // 8 bytes of zero for Root Delay & Root Dispersion
  this->_packetBuffer[12]  = 49;
  this->_packetBuffer[13]  = 0x4E;
  this->_packetBuffer[14]  = 49;
  this->_packetBuffer[15]  = 52;

  // all NTP fields have been given values, now
  // you can send a packet requesting a timestamp:
  if  (this->_poolServerName) {
    this->_udp->beginPacket(this->_poolServerName, 123);
  } else {
    this->_udp->beginPacket(this->_poolServerIP, 123);
  }
  this->_udp->write(this->_packetBuffer, NTP_PACKET_SIZE);
  this->_udp->endPacket();
  this->_sendTime = millis();

  #ifdef DEBUG_NTPClient
    Serial.println("[NTPClient] Sent UDP packet");
  #endif
}

bool NTPClient::receiveNTPPacket(unsigned long timeout) {
  int packetSize = this->_udp->parsePacket();

  if (packetSize < NTP_PACKET_SIZE) {
    if (timeout == 0) return false;

    unsigned long start = millis();
    while (millis() - start < timeout) {
      delay(1);
      packetSize = this->_udp->parsePacket();
      if (packetSize >= NTP_PACKET_SIZE) break;
    }
  }

  this->_udp->read(this->_packetBuffer, NTP_PACKET_SIZE);

  unsigned long highWord = word(this->_packetBuffer[40], this->_packetBuffer[41]);
  unsigned long lowWord = word(this->_packetBuffer[42], this->_packetBuffer[43]);
  // combine the four bytes (two words) into a long integer
  // this is NTP time (seconds since Jan 1 1900):
  unsigned long secsSince1900 = highWord << 16 | lowWord;

  this->_currentEpoch = secsSince1900 - SEVENTY_YEARS;
  int latency = (millis() - this->_sendTime);
  this->_lastUpdate = millis() - (latency / 2); // Account for latency in reading the time

  #ifdef DEBUG_NTPClient
    Serial.print("[NTPClient] Received UDP packet latency: ");
    Serial.println(latency);
  #endif

  return true;
}

void NTPClient::setRandomPort(unsigned int minValue, unsigned int maxValue) {
  randomSeed(analogRead(0));
  this->_port = random(minValue, maxValue);
}