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Do not use analogRead or ECCX08 to generate random NTP port #481

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Do not use analogRead or ECCX08 to generate random NTP port #481

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b3f2282
NTPUtils: fix whitespaces
pennam Jun 20, 2024
471296d
Do not use analogRead or ECCX08 to generate random NTP port
pennam Jun 20, 2024
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73 changes: 64 additions & 9 deletions src/utility/time/NTPUtils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -54,7 +54,7 @@ unsigned long NTPUtils::getTime(UDP & udp)
udp.stop();
return 0;
}

uint8_t ntp_packet_buf[NTP_PACKET_SIZE];
udp.read(ntp_packet_buf, NTP_PACKET_SIZE);
udp.stop();
Expand All @@ -75,7 +75,7 @@ unsigned long NTPUtils::getTime(UDP & udp)
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;
Expand All @@ -84,23 +84,78 @@ void NTPUtils::sendNTPpacket(UDP & udp)
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();
}

#ifdef NTP_USE_RANDOM_PORT
int NTPUtils::getRandomPort(int const min_port, int const max_port)
{
#if defined (BOARD_HAS_ECCX08)
return ECCX08.random(min_port, max_port);
#elif defined (ARDUINO_ARCH_ESP8266) || (ARDUINO_ARCH_ESP32)
#if defined (ARDUINO_ARCH_ESP8266) || (ARDUINO_ARCH_ESP32) || \
(ARDUINO_ARCH_RENESAS) || (ARDUINO_ARCH_MBED)
/* Uses HW Random Number Generator */
return random(min_port, max_port);
#elif defined (ARDUINO_ARCH_SAMD)
/* Use ADC to generate a seed */
randomSeed(adcSeed());
#else
randomSeed(analogRead(0));
return random(min_port, max_port);
#endif
return random(min_port, max_port);
}

#endif /* #ifndef HAS_LORA */
#if defined (ARDUINO_ARCH_SAMD)
unsigned long NTPUtils::adcSeed()
{
uint32_t seed = 0;
uint32_t bitCount = 0;
uint16_t sampctlr = ADC->SAMPCTRL.reg;

// Use lowest sampling time
ADC->SAMPCTRL.reg = 0;
// Enable ADC
ADC->CTRLA.bit.ENABLE = 1;
while (ADC->STATUS.bit.SYNCBUSY == 1);
do {
uint16_t adcReading;
// Start ADC conversion
ADC->SWTRIG.bit.START = 1;
// Wait until ADC conversion is done
while (!(ADC->INTFLAG.bit.RESRDY));
while (ADC->STATUS.bit.SYNCBUSY == 1);
// Get result
adcReading = ADC->RESULT.reg;
// Clear result ready flag
ADC->INTFLAG.reg = ADC_INTFLAG_RESRDY;
while (ADC->STATUS.bit.SYNCBUSY == 1);
// Take least significant bit
uint8_t b0 = adcReading & 0x0001;
ADC->SWTRIG.bit.START = 1;
// Wait until ADC conversion is done
while (!(ADC->INTFLAG.bit.RESRDY));
while (ADC->STATUS.bit.SYNCBUSY == 1);
// Get result
adcReading = ADC->RESULT.reg;
// Clear result ready flag
ADC->INTFLAG.reg = ADC_INTFLAG_RESRDY;
while (ADC->STATUS.bit.SYNCBUSY == 1);
// Take least significant nibble
uint8_t b1 = adcReading & 0x0001;
if (b0 == b1) {
continue;
}
seed |= b0 << bitCount;
bitCount++;
} while(bitCount < 32);
// Disable ADC
ADC->CTRLA.bit.ENABLE = 0;
// restore original sampling time
ADC->SAMPCTRL.reg = sampctlr;
return seed;
}
#endif /* ARDUINO_ARCH_SAMD */

#endif /* NTP_USE_RANDOM_PORT */

#endif /* !HAS_LORA */
3 changes: 3 additions & 0 deletions src/utility/time/NTPUtils.h
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Original file line number Diff line number Diff line change
Expand Up @@ -42,7 +42,9 @@ class NTPUtils
public:

static unsigned long getTime(UDP & udp);
#if NTP_USE_RANDOM_PORT
static int getRandomPort(int const min_port, int const max_port);
#endif

private:

Expand All @@ -57,6 +59,7 @@ class NTPUtils
static constexpr const char * NTP_TIME_SERVER = "time.arduino.cc";

static void sendNTPpacket(UDP & udp);
static unsigned long adcSeed();
};

#endif /* #ifndef HAS_LORA */
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