#include <assert.h>
#include <stddef.h>
#include <stdint.h>

typedef _Float64 float64_t;

enum packet_type {
  PACKET_TYPE__TIME_START = 0x2112858517,
  PACKET_TYPE__TIME_STOP = 0xdf75d3f8,
  PACKET_TYPE__RTT_DELAY = 0xc7065931,
  PACKET_TYPE__ACK = 0xfde7959f,
};

struct time_stop_data {
  uint32_t integer_value;
  uint32_t fraction_value;
  uint16_t integer_digits;
  uint16_t fraction_digits;
} __attribute__((__packed__));

static_assert((sizeof (struct time_stop_data)) == 4 * 3);

struct rtt_delay_data {
  float64_t offset;
} __attribute__((__packed__));

struct ack_data {
  uint64_t seq;
} __attribute__((__packed__));

static_assert((sizeof (struct rtt_delay_data)) == 8);

struct timing_packet {
  uint32_t type;
  union {
    struct time_stop_data time_stop;
    struct rtt_delay_data rtt_delay;
    struct ack_data ack;
  };
} __attribute__((__packed__));

static_assert((sizeof (struct timing_packet)) == 4 * 4);