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Added isValid() and modified implementation of forceUpdate()

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Chritzel 2017-04-11 17:31:01 +02:00 committed by GitHub
parent c561e53829
commit bbcc429f68
1 changed files with 32 additions and 2 deletions
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34
NTPClient.cpp
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@ -60,6 +60,30 @@ void NTPClient::begin(int port) {
this->_udpSetup = true; this->_udpSetup = true;
} }
bool NTPClient::isValid(byte * ntpPacket)
{
//Perform a few validity checks on the packet
if((ntpPacket[0] & 0b11000000) == 0b11000000) //Check for LI=UNSYNC
return false;
if((ntpPacket[0] & 0b00111000) >> 3 < 0b100) //Check for Version >= 4
return false;
if((ntpPacket[0] & 0b00000111) != 0b100) //Check for Mode == Server
return false;
if((ntpPacket[1] < 1) || (ntpPacket[1] > 15)) //Check for valid Stratum
return false;
if( ntpPacket[16] == 0 && ntpPacket[17] == 0 &&
ntpPacket[18] == 0 && ntpPacket[19] == 0 &&
ntpPacket[20] == 0 && ntpPacket[21] == 0 &&
ntpPacket[22] == 0 && ntpPacket[22] == 0) //Check for ReferenceTimestamp != 0
return false;
return true;
}
bool NTPClient::forceUpdate() { bool NTPClient::forceUpdate() {
#ifdef DEBUG_NTPClient #ifdef DEBUG_NTPClient
Serial.println("Update from NTP Server"); Serial.println("Update from NTP Server");
@ -73,14 +97,20 @@ bool NTPClient::forceUpdate() {
do { do {
delay ( 10 ); delay ( 10 );
cb = this->_udp->parsePacket(); cb = this->_udp->parsePacket();
if(cb > 0)
{
this->_udp->read(this->_packetBuffer, NTP_PACKET_SIZE);
if(!this->isValid(this->_packetBuffer))
cb = 0;
}
if (timeout > 100) return false; // timeout after 1000 ms if (timeout > 100) return false; // timeout after 1000 ms
timeout++; timeout++;
} while (cb == 0); } while (cb == 0);
this->_lastUpdate = millis() - (10 * (timeout + 1)); // Account for delay in reading the time this->_lastUpdate = millis() - (10 * (timeout + 1)); // Account for delay in reading the time
this->_udp->read(this->_packetBuffer, NTP_PACKET_SIZE);
unsigned long highWord = word(this->_packetBuffer[40], this->_packetBuffer[41]); unsigned long highWord = word(this->_packetBuffer[40], this->_packetBuffer[41]);
unsigned long lowWord = word(this->_packetBuffer[42], this->_packetBuffer[43]); unsigned long lowWord = word(this->_packetBuffer[42], this->_packetBuffer[43]);
// combine the four bytes (two words) into a long integer // combine the four bytes (two words) into a long integer