epicsNtp.h

/*************************************************************************\
* (C) 2014 David Lettier.
* http://www.lettier.com/
* SPDX-License-Identifier: BSD-3-Clause
\*************************************************************************/
#ifndef EPICSNTP_H
#define EPICSNTP_H

#define NTP_TIMESTAMP_DELTA 2208988800ull

int epicsNtpGetTime(char *ntpIp, struct timespec *now);

typedef struct
{

 uint8_t li_vn_mode; // Eight bits. li, vn, and mode.
 // li. Two bits. Leap indicator.
 // vn. Three bits. Version number of the protocol.
 // mode. Three bits. Client will pick mode 3 for client.

 uint8_t stratum; // Eight bits. Stratum level of the local clock.
 uint8_t poll; // Eight bits. Maximum interval between successive messages.
 uint8_t precision; // Eight bits. Precision of the local clock.

 uint32_t rootDelay; // 32 bits. Total round trip delay time.
 uint32_t rootDispersion; // 32 bits. Max error aloud from primary clock source.
 uint32_t refId; // 32 bits. Reference clock identifier.

 uint32_t refTm_s; // 32 bits. Reference time-stamp seconds.
 uint32_t refTm_f; // 32 bits. Reference time-stamp fraction of a second.

 uint32_t origTm_s; // 32 bits. Originate time-stamp seconds.
 uint32_t origTm_f; // 32 bits. Originate time-stamp fraction of a second.

 uint32_t rxTm_s; // 32 bits. Received time-stamp seconds.
 uint32_t rxTm_f; // 32 bits. Received time-stamp fraction of a second.

 uint32_t txTm_s; // 32 bits and the most important field the client cares about. Transmit time-stamp seconds.
 uint32_t txTm_f; // 32 bits. Transmit time-stamp fraction of a second.

} ntp_packet; // Total: 384 bits or 48 bytes.
#endif // EPICSNTP_H