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Reverted to using NTP for network time. The mobile network time is no…
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…t reliable.
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@dajtxx
dajtxx committed Oct 24, 2023
1 parent 37de365 commit 7b5b8c0
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Showing 4 changed files with 28 additions and 127 deletions.
2 changes: 1 addition & 1 deletion firmware/wombat/src/CAT_M1.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -106,7 +106,7 @@ bool CAT_M1::make_ready() {
r5.autoTimeZoneForBegin(true);

r5.enableAtDebugging();
r5.enableDebugging();
//r5.enableDebugging();

// This is relatively benign - it enables the network indicator GPIO pin, set error message format, etc.
// It does close all open sockets, but there should not be any open sockets at this point so that is ok.
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129 changes: 13 additions & 116 deletions firmware/wombat/src/Utils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@

#define TAG "utils"

bool getNTPTime(SARA_R5 &r5);

/**
* @brief Returns a pointer to a string representation of value, with trailing zeros removed.
Expand Down Expand Up @@ -348,86 +349,10 @@ bool wait_for_at(void) {
return false;
}

/**
* Attempt to get the current time from the modem. Times reported before 2023 from the modem are assumed to be in
* error because this firmware went into production in 2023.
*
* @param tv on return, tv.tv_sec contains a UNIX style epoch value calculated from the local time provided by the modem.
* @return true if the time from the modem is valid, otherwise false.
*/
bool get_network_time(struct timeval & tv) {
int retries = 3;
constexpr size_t time_buffer_sz = 20;
char time_buffer[time_buffer_sz + 1];
// Try a few times with a pause. The modem doesn't always get the network time quickly enough for an immediate
// query.
while (retries > 0) {
// Get the time from the R5 modem. This is given in local time with the
// timezone given as the number of 15 minute offsets from UTC, eg +40 for AEST
// and +44 for AEDT.
// Example return from r5.clock(): 23/02/13,08:07:57+44
memset(time_buffer, 0, sizeof(time_buffer_sz));
String time_str = r5.clock();
delay(20);
strncpy(time_buffer, time_str.c_str(), time_buffer_sz);
time_buffer[time_buffer_sz] = 0;

ESP_LOGI(TAG, "Time from modem: %s", time_buffer);
log_to_sdcardf("Time from modem: %s", time_buffer);

int tz;
int year;
struct tm tm{};

int field_count = sscanf(time_buffer, "%2d/%2d/%2d,%d:%d:%d%d", &year, &tm.tm_mon, &tm.tm_mday, &tm.tm_hour, &tm.tm_min, &tm.tm_sec, &tz);
// The firmware was put into production in 2023, so earlier times must be invalid. This is to capture the modem
// default value of '15/01/01,00:00:09+00'.
if (field_count == 7 && year > 22) {
// Parse the response into a tm structure which will be used to convert to an epoch value.
// Do not take account of the timezone or daylight savings. This means we'll be creating an
// epoch time using the local time, but pretending it is UTC. The timezone offset is calculated
// and applied later to make it true UTC.
tm.tm_year = year + 100; // tm.tm_year is years since 1900, and modem gives 2-digit year since 2000.
tm.tm_isdst = 0; // No daylight savings.

ESP_LOGI(TAG, "Network time: %02d/%02d/%04d %02d:%02d:%02d %02d", tm.tm_mday, tm.tm_mon, tm.tm_year + 1900,
tm.tm_hour, tm.tm_min, tm.tm_sec, tz);

tm.tm_mon -= 1; // tm.tm_month is months since January, so from 0 - 11.

// No microseconds in the calculated time.
tv.tv_usec = 0;

// Get the epoch value by converting the values in the tm structure. This will make tv.tv_sec equal to
// the current local time, but assume it is UTC. So giving it the tm generated from the response 23/02/13,08:07:57+44
// means tv.tv_sec epoch will represent 23/02/13,08:07:57 UTC.
tv.tv_sec = mktime(&tm);

// Calculate an adjustment for the epoch value based upon the timezone information supplied
// by the modem. The modem reports timezone offsets in units of 15 minutes.
int dst_offset_secs = tz * 15 * -1 * 60;
tv.tv_sec += dst_offset_secs;
ESP_LOGI(TAG, "1970 epoch calculated from modem time: %ld", tv.tv_sec);

return true;
}

ESP_LOGE(TAG, "Time too early or could not parse, wait and retry");
log_to_sdcard("[E] Time too early or could not parse, wait and retry");

delay(1000);
retries--;
}

ESP_LOGE(TAG, "Failed to parse time from modem");
log_to_sdcard("[E] Failed to parse time from modem");
return false;
}

/**
* @brief Get the R5 modem connected to the internet.
*
* This function sets the ESP32 RTC from the network time.
* This function sets the ESP32 and modem RTCs from the network time using NTP.
*
* If this function returns true, the modem has registered to the network, brought up a
* packet switched profile, and obtained an IP address. MQTT, FTP, etc can be used.
Expand Down Expand Up @@ -510,36 +435,8 @@ bool connect_to_internet(void) {
setenv("TZ", "UTC", 1);
tzset();

ESP_LOGI(TAG, "RTC time now: %s", iso8601());
log_to_sdcardf("RTC time now: %s", iso8601_buf); // Look out, this is a side-effect of calling iso8601.

bool time_set = false;
struct timeval tv{};

if (get_network_time(tv)) {
// tv.tv_sec is a time_t so difftime can be used to compare it with 'now' and get the difference in seconds.
// If the time from the ESP32 RTC is later than the time from the modem then timedelta will be
// negative.
//
// If the modem appears to be up to 10 seconds behind the RTC, assume clock drift is making the RTC run fast
// and use the modem time. If the modem appears to be in the future, also use the modem time assuming either
// the RTC is still in 1970 after booting or it is running slow.
time_t now = time(nullptr);
double timedelta = difftime(tv.tv_sec, now);
ESP_LOGI(TAG, "timedelta = %f", timedelta);
if (timedelta > -10.0) {
// Now set the system clock.
settimeofday(&tv, nullptr);
time_set = true;
} else {
ESP_LOGW(TAG, "modem time greater than 10 seconds in the past");
}
}

if ( ! time_set) {
ESP_LOGI(TAG, "Assuming bad time from modem, not setting RTC");
log_to_sdcard("Assuming bad time from modem, not setting RTC");
}
ESP_LOGI(TAG, "RTC time before ntp: %s", iso8601());
log_to_sdcardf("RTC time before ntp: %s", iso8601_buf); // Look out, this is a side-effect of calling iso8601.

log_to_sdcard("Starting PDP");

Expand All @@ -556,17 +453,17 @@ bool connect_to_internet(void) {
delay(20);
r5.bufferedPoll();

ESP_LOGI(TAG, "Attempting NTP query");
if ( ! getNTPTime(r5)) {
ESP_LOGW(TAG, "NTP query failed");
log_to_sdcard("NTP query failed");
}

ESP_LOGI(TAG, "RTC time after ntp: %s", iso8601());
log_to_sdcardf("RTC time after ntp: %s", iso8601_buf); // Look out, this is a side-effect of calling iso8601.

log_to_sdcard("cti returning");

already_called = true;
return true;
}

int get_version_string(char *buffer, size_t length) {
if (buffer == nullptr) {
return -1;
}

int i = snprintf(buffer, length, "%u.%u.%u", ver_major, ver_minor, ver_update);
return i;
}
12 changes: 12 additions & 0 deletions firmware/wombat/src/cli/peripherals/cat-m1.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,8 @@
#include "globals.h"
#include "cli/CLI.h"

bool getNTPTime(SARA_R5 &r5);

//! Sparkfun SARA-R5 library instance
extern SARA_R5 r5;
//! Holds responses from the modem
Expand Down Expand Up @@ -228,6 +230,16 @@ static int get_response(uint32_t timeout = 500) {
return pdFALSE;
}

if (!strncmp("ntp", param, paramLen)) {
bool rc = false;
if (connect_to_internet()) {
rc = getNTPTime(r5);
}

snprintf(pcWriteBuffer, xWriteBufferLen-1, "\r\n%s\r\n", rc ? "OK" : "ERROR");
return pdFALSE;
}

if (!strncmp("ok", param, paramLen)) {
LTE_Serial.print("ATI\r");
int ch = waitForChar(LTE_Serial, 250);
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12 changes: 2 additions & 10 deletions firmware/wombat/src/ntp.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -30,20 +30,12 @@ bool getNTPTime(SARA_R5 &r5) {
// set all bytes in the buffer to 0
memset(packetBuffer, 0, NTP_PACKET_SIZE);

// Initialize values needed to form NTP request
// Initialize values needed to form NTP request. The client request only needs to set version numbers & mode.
packetBuffer[0] = 0b11100011; // LI, Version, Mode
packetBuffer[1] = 0; // Stratum, or type of clock
packetBuffer[2] = 6; // Polling Interval
packetBuffer[3] = 0xEC; // Peer Clock Precision
// 8 bytes of zero for Root Delay & Root Dispersion
packetBuffer[12] = 49;
packetBuffer[13] = 0x4E;
packetBuffer[14] = 49;
packetBuffer[15] = 52;

//=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

//Allocate a UDP socket to talk to the NTP server
// Allocate a UDP socket to talk to the NTP server

int socketNum = r5.socketOpen(SARA_R5_UDP);
if (socketNum == -1) {
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