- m->retry_interval = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
-
- r = manager_arm_timer(m, m->retry_interval);
- if (r < 0) {
- log_error("Failed to rearm timer: %s", strerror(-r));
- return r;
- }
-
- r = sd_event_add_time(
- m->event,
- &m->event_timeout,
- CLOCK_MONOTONIC,
- now(CLOCK_MONOTONIC) + TIMEOUT_USEC, 0,
- manager_timeout, m);
- if (r < 0) {
- log_error("Failed to arm timeout timer: %s", strerror(-r));
- return r;
- }
-
- return 0;
-}
-
-static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
- Manager *m = userdata;
-
- assert(m);
-
- return manager_send_request(m);
-}
-
-static int manager_arm_timer(Manager *m, usec_t next) {
- int r;
-
- assert(m);
- assert(m->event_receive);
-
- if (next == 0) {
- m->event_timer = sd_event_source_unref(m->event_timer);
- return 0;
- }
-
- if (m->event_timer) {
- r = sd_event_source_set_time(m->event_timer, now(CLOCK_MONOTONIC) + next);
- if (r < 0)
- return r;
-
- return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
- }
-
- return sd_event_add_time(
- m->event,
- &m->event_timer,
- CLOCK_MONOTONIC,
- now(CLOCK_MONOTONIC) + next, 0,
- manager_timer, m);
-}
-
-static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
- Manager *m = userdata;
-
- assert(m);
-
- /* rearm timer */
- manager_clock_watch_setup(m);
-
- /* skip our own jumps */
- if (m->jumped) {
- m->jumped = false;
- return 0;
- }
-
- /* resync */
- log_info("System time changed. Resyncing.");
- m->poll_resync = true;
- return manager_send_request(m);
-}
-
-/* wake up when the system time changes underneath us */
-static int manager_clock_watch_setup(Manager *m) {
-
- struct itimerspec its = {
- .it_value.tv_sec = TIME_T_MAX
- };
-
- int r;
-
- assert(m);
-
- m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
- safe_close(m->clock_watch_fd);
-
- m->clock_watch_fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
- if (m->clock_watch_fd < 0) {
- log_error("Failed to create timerfd: %m");
- return -errno;
- }
-
- if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0) {
- log_error("Failed to set up timerfd: %m");
- return -errno;
- }
-
- r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, manager_clock_watch, m);
- if (r < 0) {
- log_error("Failed to create clock watch event source: %s", strerror(-r));
- return r;
- }
-
- return 0;
-}
-
-static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
- struct timex tmx = {};
- int r;
-
- assert(m);
-
- /*
- * For small deltas, tell the kernel to gradually adjust the system
- * clock to the NTP time, larger deltas are just directly set.
- *
- * Clear STA_UNSYNC, it will enable the kernel's 11-minute mode, which
- * syncs the system time periodically to the hardware clock.
- */
- if (fabs(offset) < NTP_MAX_ADJUST) {
- tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR;
- tmx.status = STA_PLL;
- tmx.offset = offset * NSEC_PER_SEC;
- tmx.constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4;
- tmx.maxerror = 0;
- tmx.esterror = 0;
- log_debug(" adjust (slew): %+.3f sec\n", offset);
- } else {
- tmx.modes = ADJ_SETOFFSET | ADJ_NANO;
-
- /* ADJ_NANO uses nanoseconds in the microseconds field */
- tmx.time.tv_sec = (long)offset;
- tmx.time.tv_usec = (offset - tmx.time.tv_sec) * NSEC_PER_SEC;
-
- /* the kernel expects -0.3s as {-1, 7000.000.000} */
- if (tmx.time.tv_usec < 0) {
- tmx.time.tv_sec -= 1;
- tmx.time.tv_usec += NSEC_PER_SEC;
- }
-
- m->jumped = true;
- log_debug(" adjust (jump): %+.3f sec\n", offset);
- }
-
- switch (leap_sec) {
- case 1:
- tmx.status |= STA_INS;
- break;
- case -1:
- tmx.status |= STA_DEL;
- break;
- }
-
- r = clock_adjtime(CLOCK_REALTIME, &tmx);
-
- save_clock();
-
- if (r < 0)
- return r;
-
- m->drift_ppm = tmx.freq / 65536;
-
- log_debug(" status : %04i %s\n"
- " time now : %li.%03lli\n"
- " constant : %li\n"
- " offset : %+.3f sec\n"
- " freq offset : %+li (%i ppm)\n",
- tmx.status, tmx.status & STA_UNSYNC ? "" : "sync",
- tmx.time.tv_sec, tmx.time.tv_usec / NSEC_PER_MSEC,
- tmx.constant,
- (double)tmx.offset / NSEC_PER_SEC,
- tmx.freq, m->drift_ppm);
-
- return 0;
-}
-
-static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
- unsigned int i, idx_cur, idx_new, idx_min;
- double jitter;
- double j;
-
- assert(m);
-
- m->packet_count++;
-
- /* ignore initial sample */
- if (m->packet_count == 1)
- return false;
-
- /* store the current data in our samples array */
- idx_cur = m->samples_idx;
- idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
- m->samples_idx = idx_new;
- m->samples[idx_new].offset = offset;
- m->samples[idx_new].delay = delay;
-
- /* calculate new jitter value from the RMS differences relative to the lowest delay sample */
- jitter = m->samples_jitter;
- for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
- if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
- idx_min = i;
-
- j = 0;
- for (i = 0; i < ELEMENTSOF(m->samples); i++)
- j += square(m->samples[i].offset - m->samples[idx_min].offset);
- m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
-
- /* ignore samples when resyncing */
- if (m->poll_resync)
- return false;
-
- /* always accept offset if we are farther off than the round-trip delay */
- if (fabs(offset) > delay)
- return false;
-
- /* we need a few samples before looking at them */
- if (m->packet_count < 4)
- return false;
-
- /* do not accept anything worse than the maximum possible error of the best sample */
- if (fabs(offset) > m->samples[idx_min].delay)
- return true;
-
- /* compare the difference between the current offset to the previous offset and jitter */
- return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
-}
-
-static void manager_adjust_poll(Manager *m, double offset, bool spike) {
- assert(m);
-
- if (m->poll_resync) {
- m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
- m->poll_resync = false;
- return;
- }
-
- /* set to minimal poll interval */
- if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
- m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
- return;
- }
-
- /* increase polling interval */
- if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
- if (m->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
- m->poll_interval_usec *= 2;
- return;
- }
-
- /* decrease polling interval */
- if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
- if (m->poll_interval_usec > NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC)
- m->poll_interval_usec /= 2;
- return;
- }
-}
-
-static bool sockaddr_equal(union sockaddr_union *a, union sockaddr_union *b) {
- assert(a);
- assert(b);
-
- if (a->sa.sa_family != b->sa.sa_family)
- return false;
-
- if (a->sa.sa_family == AF_INET)
- return a->in.sin_addr.s_addr == b->in.sin_addr.s_addr;
-
- if (a->sa.sa_family == AF_INET6)
- return memcmp(&a->in6.sin6_addr, &b->in6.sin6_addr, sizeof(a->in6.sin6_addr)) == 0;
-
- return false;
-}
-
-static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
- Manager *m = userdata;
- struct ntp_msg ntpmsg;
-
- struct iovec iov = {
- .iov_base = &ntpmsg,
- .iov_len = sizeof(ntpmsg),
- };
- union {
- struct cmsghdr cmsghdr;
- uint8_t buf[CMSG_SPACE(sizeof(struct timeval))];
- } control;
- union sockaddr_union server_addr;
- struct msghdr msghdr = {
- .msg_iov = &iov,
- .msg_iovlen = 1,
- .msg_control = &control,
- .msg_controllen = sizeof(control),
- .msg_name = &server_addr,
- .msg_namelen = sizeof(server_addr),
- };
- struct cmsghdr *cmsg;
- struct timespec now_ts;
- struct timeval *recv_time;
- ssize_t len;
- double origin, receive, trans, dest;
- double delay, offset;
- bool spike;
- int leap_sec;
- int r;
-
- assert(source);
- assert(m);
-
- if (revents & (EPOLLHUP|EPOLLERR)) {
- log_warning("Server connection returned error.");
- return manager_connect(m);
- }
-
- len = recvmsg(fd, &msghdr, MSG_DONTWAIT);
- if (len < 0) {
- if (errno == EAGAIN)
- return 0;
-
- log_warning("Error receiving message. Disconnecting.");
- return manager_connect(m);
- }
-
- if (iov.iov_len < sizeof(struct ntp_msg)) {
- log_warning("Invalid response from server. Disconnecting.");
- return manager_connect(m);
- }
-
- if (!m->current_server_name ||
- !m->current_server_address ||
- !sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
- log_debug("Response from unknown server.");
- return 0;
- }
-
- recv_time = NULL;
- for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {
- if (cmsg->cmsg_level != SOL_SOCKET)
- continue;
-
- switch (cmsg->cmsg_type) {
- case SCM_TIMESTAMP:
- recv_time = (struct timeval *) CMSG_DATA(cmsg);
- break;
- }
- }
- if (!recv_time) {
- log_error("Invalid packet timestamp.");
- return -EINVAL;
- }
-
- if (!m->pending) {
- log_debug("Unexpected reply. Ignoring.");
- return 0;
- }
-
- /* check our "time cookie" (we just stored nanoseconds in the fraction field) */
- if (be32toh(ntpmsg.origin_time.sec) != m->trans_time.tv_sec + OFFSET_1900_1970 ||
- be32toh(ntpmsg.origin_time.frac) != m->trans_time.tv_nsec) {
- log_debug("Invalid reply; not our transmit time. Ignoring.");
- return 0;
- }
-
- m->event_timeout = sd_event_source_unref(m->event_timeout);
-
- if (be32toh(ntpmsg.recv_time.sec) < TIME_EPOCH + OFFSET_1900_1970 ||
- be32toh(ntpmsg.trans_time.sec) < TIME_EPOCH + OFFSET_1900_1970) {
- log_debug("Invalid reply, returned times before epoch. Ignoring.");
- return manager_connect(m);
- }
-
- if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC) {
- log_debug("Server is not synchronized. Disconnecting.");
- return manager_connect(m);
- }
-
- if (!IN_SET(NTP_FIELD_VERSION(ntpmsg.field), 3, 4)) {
- log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
- return manager_connect(m);
- }
-
- if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
- log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
- return manager_connect(m);
- }
-
- /* valid packet */
- m->pending = false;
- m->retry_interval = 0;
-
- /* announce leap seconds */
- if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
- leap_sec = 1;
- else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
- leap_sec = -1;
- else
- leap_sec = 0;
-
- /*
- * "Timestamp Name ID When Generated
- * ------------------------------------------------------------
- * Originate Timestamp T1 time request sent by client
- * Receive Timestamp T2 time request received by server
- * Transmit Timestamp T3 time reply sent by server
- * Destination Timestamp T4 time reply received by client
- *
- * The round-trip delay, d, and system clock offset, t, are defined as:
- * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
- */
- assert_se(clock_gettime(CLOCK_MONOTONIC, &now_ts) >= 0);
- origin = tv_to_d(recv_time) - (ts_to_d(&now_ts) - ts_to_d(&m->trans_time_mon)) + OFFSET_1900_1970;
- receive = ntp_ts_to_d(&ntpmsg.recv_time);
- trans = ntp_ts_to_d(&ntpmsg.trans_time);
- dest = tv_to_d(recv_time) + OFFSET_1900_1970;
-
- offset = ((receive - origin) + (trans - dest)) / 2;
- delay = (dest - origin) - (trans - receive);
-
- spike = manager_sample_spike_detection(m, offset, delay);
-
- manager_adjust_poll(m, offset, spike);
-
- log_debug("NTP response:\n"
- " leap : %u\n"
- " version : %u\n"
- " mode : %u\n"
- " stratum : %u\n"
- " precision : %.6f sec (%d)\n"
- " reference : %.4s\n"
- " origin : %.3f\n"
- " receive : %.3f\n"
- " transmit : %.3f\n"
- " dest : %.3f\n"
- " offset : %+.3f sec\n"
- " delay : %+.3f sec\n"
- " packet count : %"PRIu64"\n"
- " jitter : %.3f%s\n"
- " poll interval: %llu\n",
- NTP_FIELD_LEAP(ntpmsg.field),
- NTP_FIELD_VERSION(ntpmsg.field),
- NTP_FIELD_MODE(ntpmsg.field),
- ntpmsg.stratum,
- exp2(ntpmsg.precision), ntpmsg.precision,
- ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
- origin - OFFSET_1900_1970,
- receive - OFFSET_1900_1970,
- trans - OFFSET_1900_1970,
- dest - OFFSET_1900_1970,
- offset, delay,
- m->packet_count,
- m->samples_jitter, spike ? " spike" : "",
- m->poll_interval_usec / USEC_PER_SEC);
-
- if (!spike) {
- r = manager_adjust_clock(m, offset, leap_sec);
- if (r < 0)
- log_error("Failed to call clock_adjtime(): %m");
- }
-
- log_info("interval/delta/delay/jitter/drift %llus/%+.3fs/%.3fs/%.3fs/%+ippm%s",
- m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_ppm,
- spike ? " (ignored)" : "");
-
- r = manager_arm_timer(m, m->poll_interval_usec);
- if (r < 0) {
- log_error("Failed to rearm timer: %s", strerror(-r));
- return r;
- }
-
- return 0;
-}
-
-static int manager_listen_setup(Manager *m) {
- union sockaddr_union addr = {};
- static const int tos = IPTOS_LOWDELAY;
- static const int on = 1;
- int r;
-
- assert(m);