From f5399d8108caa4e76165604d167fa7e439f44938 Mon Sep 17 00:00:00 2001 From: Klaus K Wilting Date: Sat, 7 Mar 2020 23:18:36 +0100 Subject: [PATCH] timesync code refactored --- include/timesync.h | 9 +++-- src/lorawan.cpp | 2 +- src/timesync.cpp | 84 ++++++++++++++++++---------------------------- 3 files changed, 37 insertions(+), 58 deletions(-) diff --git a/include/timesync.h b/include/timesync.h index e66fb7ef..71ba8c57 100644 --- a/include/timesync.h +++ b/include/timesync.h @@ -5,12 +5,11 @@ #include "irqhandler.h" #include "timekeeper.h" -#define TIME_SYNC_FRAME_LENGTH 0x07 // timeserver answer frame length [bytes] +#define TIME_SYNC_FRAME_LENGTH 6 // timeserver answer frame length [bytes] #define TIME_SYNC_FIXUP 16 // compensation for processing time [milliseconds] -#define TIMEREQUEST_MAX_SEQNO 0xfe // threshold for wrap around seqno -#define TIMEREQUEST_END \ - (TIMEREQUEST_MAX_SEQNO + 1) // marker for end of timesync handshake -#define GPS_UTC_DIFF 315964800 +#define TIMEREQUEST_MAX_SEQNO 0xfe // threshold for wrap around seqNo +#define TIMEREQUEST_END (TIMEREQUEST_MAX_SEQNO + 1) // end of handshake marker +#define GPS_UTC_DIFF 315964800 // seconds diff between gps and utc epoch enum timesync_t { timesync_tx, diff --git a/src/lorawan.cpp b/src/lorawan.cpp index 6e65643d..e99ff7c5 100644 --- a/src/lorawan.cpp +++ b/src/lorawan.cpp @@ -472,7 +472,7 @@ void myRxCallback(void *pUserData, uint8_t port, const uint8_t *pMsg, #if (TIME_SYNC_LORASERVER) case TIMEPORT: // get and store gwtime from payload - timesync_serverAnswer(&pMsg, nMsg); + timesync_serverAnswer(const_cast(pMsg), nMsg); #endif // decode any piggybacked downlink MAC commands if we want to print those diff --git a/src/timesync.cpp b/src/timesync.cpp index d270f4cd..c955aa5a 100644 --- a/src/timesync.cpp +++ b/src/timesync.cpp @@ -3,11 +3,13 @@ ///--> IMPORTANT LICENSE NOTE for timesync option 1 in this file <--/// PLEASE NOTE: There is a patent filed for the time sync algorithm used in the -code of this file. The shown implementation example is covered by the -repository's licencse, but you may not be eligible to deploy the applied -algorithm in applications without granted license by the patent holder. +code of this file for timesync option TIME_SYNC_LORASERVER. The shown +implementation example is covered by the repository's licencse, but you may not +be eligible to deploy the applied algorithm in applications without granted +license by the patent holder. -You may use timesync option 2 if you do not want or cannot accept this. +You may use timesync option TIME_SYNC_LORAWAN if you do not want or cannot +accept this. */ @@ -27,9 +29,7 @@ static const char TAG[] = __FILE__; static bool timeSyncPending = false; static uint8_t time_sync_seqNo = (uint8_t)random(TIMEREQUEST_MAX_SEQNO), sample_idx; -static uint16_t timestamp_msec; -static uint32_t timestamp_sec, - timesync_timestamp[TIME_SYNC_SAMPLES][no_of_timestamps]; +static uint32_t timesync_timestamp[TIME_SYNC_SAMPLES][no_of_timestamps]; static TaskHandle_t timeSyncProcTask = NULL; // create task for timeserver handshake processing, called from main.cpp @@ -64,7 +64,7 @@ void IRAM_ATTR timesync_processReq(void *taskparameter) { // this task is an endless loop, waiting in blocked mode, until it is // unblocked by timesync_sendReq(). It then waits to be notified from - // timesync_serverAnswer(), which is called from LMIC each time a timestamp + // timesync_serverAnswer(), which is called from LMIC each time a timestamp // from the timesource via LORAWAN arrived. // --- asnychronous part: generate and collect timestamps from gateway --- @@ -89,31 +89,31 @@ void IRAM_ATTR timesync_processReq(void *taskparameter) { // send timesync request to timeserver or networkserver #if (TIME_SYNC_LORASERVER) - // timesync option 1: use external timeserver (for LoRAWAN < 1.0.3) - // ask timeserver + // ask user's timeserver (for LoRAWAN < 1.0.3) payload.reset(); payload.addByte(time_sync_seqNo); SendPayload(TIMEPORT, prio_high); #elif (TIME_SYNC_LORAWAN) - // timesync option 2: use LoRAWAN network time (requires LoRAWAN >= 1.0.3) - // ask networkserver + // ask network (requires LoRAWAN >= 1.0.3) LMIC_requestNetworkTime(timesync_serverAnswer, &time_sync_seqNo); + // open a receive window to immediately get DevTimeAns + LMIC_sendAlive(); #endif // open a receive window to immediately get the answer (Class A device) - LMIC_sendAlive(); + // LMIC_sendAlive(); // wait until a timestamp was received if (xTaskNotifyWait(0x00, ULONG_MAX, &seqNo, pdMS_TO_TICKS(TIME_SYNC_TIMEOUT * 1000)) == pdFALSE) { - ESP_LOGW(TAG, "[%0.3f] Timesync handshake error: timeout", - millis() / 1000.0); + ESP_LOGW(TAG, "[%0.3f] Timesync aborted: timed out", millis() / 1000.0); goto Fail; // no valid sequence received before timeout } // check if we are in handshake with server if (seqNo != time_sync_seqNo) { - ESP_LOGW(TAG, "[%0.3f] Timesync handshake aborted", millis() / 1000.0); + ESP_LOGW(TAG, "[%0.3f] Timesync aborted: handshake out of sync", + millis() / 1000.0); goto Fail; } @@ -178,6 +178,7 @@ void timesync_storeReq(uint32_t timestamp, timesync_t timestamp_type) { // callback function to receive network time server answer void IRAM_ATTR timesync_serverAnswer(void *pUserData, int flag) { + // if no timesync handshake is pending then exit if (!timeSyncPending) return; @@ -186,34 +187,30 @@ void IRAM_ATTR timesync_serverAnswer(void *pUserData, int flag) { mask_user_IRQ(); int rc = 0; - uint32_t timestamp_sec; + uint8_t seqNo = *(uint8_t *)pUserData; uint16_t timestamp_msec; + uint32_t timestamp_sec; #if (TIME_SYNC_LORASERVER) - // store LMIC time when we received the timesync answer - timesync_storeReq(osticks2ms(os_getTime()), timesync_rx); - // pUserData: contains pointer to payload buffer // flag: length of buffer - /* - parse 6 byte timesync_answer: + // store LMIC time when we received the timesync answer + timesync_storeReq(osticks2ms(os_getTime()), timesync_rx); - byte meaning - 1 sequence number (taken from node's time_sync_req) - 2..5 current second (from epoch time 1970) - 6 1/250ths fractions of current second - */ + // parse timesync_answer: + // byte meaning + // 0 sequence number (taken from node's time_sync_req) + // 1..4 current second (from UTC epoch) + // 5 1/250ths fractions of current second - // Explicit conversion from void* to uint8_t* to avoid compiler errors - uint8_t *p = (uint8_t *)pUserData; - // Get payload buffer from pUserData - uint8_t *buf = p; + // swap byte order from msb to lsb, note: this is a platform dependent hack + timestamp_sec = __builtin_bswap32(*(uint32_t *)(pUserData + 1)); - // extract 1 byte timerequest sequence number from payload - uint8_t seqNo = buf[0]; - buf++; + // one step being 1/250th sec * 1000 = 4msec + timestamp_msec = *(uint8_t *)(pUserData + 5); + timestamp_msec *= 4; // if no time is available or spurious buffer then exit if (flag != TIME_SYNC_FRAME_LENGTH) { @@ -226,29 +223,12 @@ void IRAM_ATTR timesync_serverAnswer(void *pUserData, int flag) { goto Exit; // failure } - // pointer to 4 bytes msb order - uint32_t *timestamp_ptr; - // extract 4 bytes containing gateway time in UTC seconds since unix - // epoch 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 a platform dependent hack - timestamp_sec = __builtin_bswap32(*timestamp_ptr); - buf += 4; - // extract 1 byte containing fractional seconds in 2^-8 second steps - // one step being 1/250th sec * 1000 = 4msec - timestamp_msec = buf[0] * 4; - goto Finish; #elif (TIME_SYNC_LORAWAN) // pUserData: contains pointer to SeqNo - // flagSuccess: indicates if we got a recent time from the network - - // Explicit conversion from void* to uint8_t* to avoid compiler errors - uint8_t *p = (uint8_t *)pUserData; - // Get seqNo from pUserData - uint8_t seqNo = *p; + // flag: indicates if we got a recent time from the network if (flag != 1) { ESP_LOGW(TAG, "[%0.3f] Network did not answer time request",