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timesync.cpp cleanups

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This commit is contained in:
Verkehrsrot 2019-10-05 13:15:45 +02:00
parent 36d9b3dedb
commit 06fb69d304
1 changed files with 28 additions and 14 deletions
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40
src/timesync.cpp
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@ -154,18 +154,30 @@ void store_time_sync_req(uint32_t timestamp) {
timestamp % 1000);
}
// process timeserver timestamp answer, called from lorawan.cpp
// process timeserver timestamp answer, called by myRxCallback() in lorawan.cpp
int recv_timesync_ans(const uint8_t buf[], const uint8_t buf_len) {
uint8_t seq_no = buf[0];
buf++;
/*
parse 7 byte timesync_answer:
byte meaning
1 sequence number (taken from node's time_sync_req)
2 timezone in 15 minutes steps
3..6 current second (from epoch time 1970)
7 1/250ths fractions of current second
*/
// if no timesync handshake is pending then exit
if (!timeSyncPending)
return 0; // failure
// extract 1 byte timerequest sequence number from buffer
uint8_t seq_no = buf[0];
buf++;
// if no time is available or spurious buffer then exit
if (buf_len != TIME_SYNC_FRAME_LENGTH) {
if (buf[0] == 0xff)
if (seq_no == 0xff)
ESP_LOGI(TAG, "[%0.3f] Timeserver error: no confident time available",
millis() / 1000.0);
else
@ -178,24 +190,26 @@ int recv_timesync_ans(const uint8_t buf[], const uint8_t buf_len) {
uint8_t k = seq_no % TIME_SYNC_SAMPLES;
// the 5th byte contains the fractional seconds in 2^-8 second steps
// (= 1/250th sec), we convert this to ms
uint16_t timestamp_msec = 4 * buf[6];
// pointers to 4 bytes 4 bytes containing UTC seconds since unix epoch, msb
// pointers to 4 bytes containing UTC seconds since unix epoch, msb
uint32_t timestamp_sec, *timestamp_ptr;
uint32_t timezone_sec;
// extract timezone from buffer (in 15min steps, one step being 15min * 60s = 900s)
timezone_sec = buf[0]*900;
// extract 1 byte timezone from buffer (one step being 15min * 60s = 900s)
uint32_t timezone_sec = buf[0] * 900;
buf++;
// convert buffer to uint32_t, octet order is big endian
// extract 4 bytes timestamp from buffer
// and convert it to uint32_t, octet order is big endian
timestamp_ptr = (uint32_t *)buf;
// swap byte order from msb to lsb, note: this is platform dependent
timestamp_sec = __builtin_bswap32(*timestamp_ptr);
buf += 4;
// extract 1 byte fractional seconds in 2^-8 second steps
// (= 1/250th sec), we convert this to ms
uint16_t timestamp_msec = 4 * buf[0];
// construct the timepoint when message was seen on gateway
time_sync_rx[k] += seconds(timestamp_sec+timezone_sec) + milliseconds(timestamp_msec);
time_sync_rx[k] +=
seconds(timestamp_sec + timezone_sec) + milliseconds(timestamp_msec);
// we guess timepoint is recent if it newer than code compile date
if (timeIsValid(myClock::to_time_t(time_sync_rx[k]))) {