summaryrefslogtreecommitdiff
path: root/src/systemd-timesync/timesyncd-manager.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/systemd-timesync/timesyncd-manager.c')
-rw-r--r--src/systemd-timesync/timesyncd-manager.c1156
1 files changed, 1156 insertions, 0 deletions
diff --git a/src/systemd-timesync/timesyncd-manager.c b/src/systemd-timesync/timesyncd-manager.c
new file mode 100644
index 0000000000..6a4b52af69
--- /dev/null
+++ b/src/systemd-timesync/timesyncd-manager.c
@@ -0,0 +1,1156 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2014 Kay Sievers, Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <math.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <resolv.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/timerfd.h>
+#include <sys/timex.h>
+#include <sys/types.h>
+#include <time.h>
+
+#include <systemd/sd-daemon.h>
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "list.h"
+#include "log.h"
+#include "missing.h"
+#include "network-util.h"
+#include "ratelimit.h"
+#include "socket-util.h"
+#include "sparse-endian.h"
+#include "string-util.h"
+#include "strv.h"
+#include "time-util.h"
+#include "timesyncd-conf.h"
+#include "timesyncd-manager.h"
+#include "util.h"
+
+#ifndef ADJ_SETOFFSET
+#define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
+#endif
+
+/* expected accuracy of time synchronization; used to adjust the poll interval */
+#define NTP_ACCURACY_SEC 0.2
+
+/*
+ * "A client MUST NOT under any conditions use a poll interval less
+ * than 15 seconds."
+ */
+#define NTP_POLL_INTERVAL_MIN_SEC 32
+#define NTP_POLL_INTERVAL_MAX_SEC 2048
+
+/*
+ * Maximum delta in seconds which the system clock is gradually adjusted
+ * (slew) to approach the network time. Deltas larger that this are set by
+ * letting the system time jump. The kernel's limit for adjtime is 0.5s.
+ */
+#define NTP_MAX_ADJUST 0.4
+
+/* NTP protocol, packet header */
+#define NTP_LEAP_PLUSSEC 1
+#define NTP_LEAP_MINUSSEC 2
+#define NTP_LEAP_NOTINSYNC 3
+#define NTP_MODE_CLIENT 3
+#define NTP_MODE_SERVER 4
+#define NTP_FIELD_LEAP(f) (((f) >> 6) & 3)
+#define NTP_FIELD_VERSION(f) (((f) >> 3) & 7)
+#define NTP_FIELD_MODE(f) ((f) & 7)
+#define NTP_FIELD(l, v, m) (((l) << 6) | ((v) << 3) | (m))
+
+/* Maximum acceptable root distance in seconds. */
+#define NTP_MAX_ROOT_DISTANCE 5.0
+
+/* Maximum number of missed replies before selecting another source. */
+#define NTP_MAX_MISSED_REPLIES 2
+
+/*
+ * "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
+ * in seconds relative to 0h on 1 January 1900."
+ */
+#define OFFSET_1900_1970 UINT64_C(2208988800)
+
+#define RETRY_USEC (30*USEC_PER_SEC)
+#define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
+#define RATELIMIT_BURST 10
+
+#define TIMEOUT_USEC (10*USEC_PER_SEC)
+
+struct ntp_ts {
+ be32_t sec;
+ be32_t frac;
+} _packed_;
+
+struct ntp_ts_short {
+ be16_t sec;
+ be16_t frac;
+} _packed_;
+
+struct ntp_msg {
+ uint8_t field;
+ uint8_t stratum;
+ int8_t poll;
+ int8_t precision;
+ struct ntp_ts_short root_delay;
+ struct ntp_ts_short root_dispersion;
+ char refid[4];
+ struct ntp_ts reference_time;
+ struct ntp_ts origin_time;
+ struct ntp_ts recv_time;
+ struct ntp_ts trans_time;
+} _packed_;
+
+static int manager_arm_timer(Manager *m, usec_t next);
+static int manager_clock_watch_setup(Manager *m);
+static int manager_listen_setup(Manager *m);
+static void manager_listen_stop(Manager *m);
+
+static double ntp_ts_short_to_d(const struct ntp_ts_short *ts) {
+ return be16toh(ts->sec) + (be16toh(ts->frac) / 65536.0);
+}
+
+static double ntp_ts_to_d(const struct ntp_ts *ts) {
+ return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
+}
+
+static double ts_to_d(const struct timespec *ts) {
+ return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
+}
+
+static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
+ _cleanup_free_ char *pretty = NULL;
+ Manager *m = userdata;
+
+ assert(m);
+ assert(m->current_server_name);
+ assert(m->current_server_address);
+
+ server_address_pretty(m->current_server_address, &pretty);
+ log_info("Timed out waiting for reply from %s (%s).", strna(pretty), m->current_server_name->string);
+
+ return manager_connect(m);
+}
+
+static int manager_send_request(Manager *m) {
+ _cleanup_free_ char *pretty = NULL;
+ struct ntp_msg ntpmsg = {
+ /*
+ * "The client initializes the NTP message header, sends the request
+ * to the server, and strips the time of day from the Transmit
+ * Timestamp field of the reply. For this purpose, all the NTP
+ * header fields are set to 0, except the Mode, VN, and optional
+ * Transmit Timestamp fields."
+ */
+ .field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
+ };
+ ssize_t len;
+ int r;
+
+ assert(m);
+ assert(m->current_server_name);
+ assert(m->current_server_address);
+
+ m->event_timeout = sd_event_source_unref(m->event_timeout);
+
+ r = manager_listen_setup(m);
+ if (r < 0)
+ return log_warning_errno(r, "Failed to setup connection socket: %m");
+
+ /*
+ * Set transmit timestamp, remember it; the server will send that back
+ * as the origin timestamp and we have an indication that this is the
+ * matching answer to our request.
+ *
+ * The actual value does not matter, We do not care about the correct
+ * NTP UINT_MAX fraction; we just pass the plain nanosecond value.
+ */
+ assert_se(clock_gettime(clock_boottime_or_monotonic(), &m->trans_time_mon) >= 0);
+ assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
+ ntpmsg.trans_time.sec = htobe32(m->trans_time.tv_sec + OFFSET_1900_1970);
+ ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
+
+ server_address_pretty(m->current_server_address, &pretty);
+
+ len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
+ if (len == sizeof(ntpmsg)) {
+ m->pending = true;
+ log_debug("Sent NTP request to %s (%s).", strna(pretty), m->current_server_name->string);
+ } else {
+ log_debug_errno(errno, "Sending NTP request to %s (%s) failed: %m", strna(pretty), m->current_server_name->string);
+ return manager_connect(m);
+ }
+
+ /* re-arm timer with increasing timeout, in case the packets never arrive back */
+ if (m->retry_interval > 0) {
+ if (m->retry_interval < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
+ m->retry_interval *= 2;
+ } else
+ m->retry_interval = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
+
+ r = manager_arm_timer(m, m->retry_interval);
+ if (r < 0)
+ return log_error_errno(r, "Failed to rearm timer: %m");
+
+ m->missed_replies++;
+ if (m->missed_replies > NTP_MAX_MISSED_REPLIES) {
+ r = sd_event_add_time(
+ m->event,
+ &m->event_timeout,
+ clock_boottime_or_monotonic(),
+ now(clock_boottime_or_monotonic()) + TIMEOUT_USEC, 0,
+ manager_timeout, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to arm timeout timer: %m");
+ }
+
+ 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);
+
+ 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_boottime_or_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_boottime_or_monotonic(),
+ now(clock_boottime_or_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_debug("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)
+ return log_error_errno(errno, "Failed to create timerfd: %m");
+
+ if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0)
+ return log_error_errno(errno, "Failed to set up timerfd: %m");
+
+ r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, manager_clock_watch, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create clock watch event source: %m");
+
+ 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.
+ */
+ 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", offset);
+ } else {
+ tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET;
+
+ /* 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", offset);
+ }
+
+ /*
+ * An unset STA_UNSYNC will enable the kernel's 11-minute mode,
+ * which syncs the system time periodically to the RTC.
+ *
+ * In case the RTC runs in local time, never touch the RTC,
+ * we have no way to properly handle daylight saving changes and
+ * mobile devices moving between time zones.
+ */
+ if (m->rtc_local_time)
+ tmx.status |= STA_UNSYNC;
+
+ switch (leap_sec) {
+ case 1:
+ tmx.status |= STA_INS;
+ break;
+ case -1:
+ tmx.status |= STA_DEL;
+ break;
+ }
+
+ r = clock_adjtime(CLOCK_REALTIME, &tmx);
+ if (r < 0)
+ return -errno;
+
+ /* If touch fails, there isn't much we can do. Maybe it'll work next time. */
+ (void) touch("/var/lib/systemd/clock");
+
+ m->drift_ppm = tmx.freq / 65536;
+
+ log_debug(" status : %04i %s\n"
+ " time now : %li.%03llu\n"
+ " constant : %li\n"
+ " offset : %+.3f sec\n"
+ " freq offset : %+li (%i ppm)\n",
+ tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
+ tmx.time.tv_sec, (unsigned long long) (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 += pow(m->samples[i].offset - m->samples[idx_min].offset, 2);
+ 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 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 *recv_time;
+ ssize_t len;
+ double origin, receive, trans, dest;
+ double delay, offset;
+ double root_distance;
+ 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);
+ }
+
+ /* Too short or too long packet? */
+ if (iov.iov_len < sizeof(struct ntp_msg) || (msghdr.msg_flags & MSG_TRUNC)) {
+ 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;
+ CMSG_FOREACH(cmsg, &msghdr) {
+ if (cmsg->cmsg_level != SOL_SOCKET)
+ continue;
+
+ switch (cmsg->cmsg_type) {
+ case SCM_TIMESTAMPNS:
+ recv_time = (struct timespec *) CMSG_DATA(cmsg);
+ break;
+ }
+ }
+ if (!recv_time) {
+ log_error("Invalid packet timestamp.");
+ return -EINVAL;
+ }
+
+ if (!m->pending) {
+ log_debug("Unexpected reply. Ignoring.");
+ return 0;
+ }
+
+ m->missed_replies = 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 ||
+ ntpmsg.stratum == 0 || ntpmsg.stratum >= 16) {
+ 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);
+ }
+
+ root_distance = ntp_ts_short_to_d(&ntpmsg.root_delay) / 2 + ntp_ts_short_to_d(&ntpmsg.root_dispersion);
+ if (root_distance > NTP_MAX_ROOT_DISTANCE) {
+ log_debug("Server has too large root distance. Disconnecting.");
+ return manager_connect(m);
+ }
+
+ /* valid packet */
+ m->pending = false;
+ m->retry_interval = 0;
+
+ /* Stop listening */
+ manager_listen_stop(m);
+
+ /* 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"
+ */
+ origin = ts_to_d(&m->trans_time) + OFFSET_1900_1970;
+ receive = ntp_ts_to_d(&ntpmsg.recv_time);
+ trans = ntp_ts_to_d(&ntpmsg.trans_time);
+ dest = ts_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"
+ " root distance: %.6f sec\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: " USEC_FMT "\n",
+ NTP_FIELD_LEAP(ntpmsg.field),
+ NTP_FIELD_VERSION(ntpmsg.field),
+ NTP_FIELD_MODE(ntpmsg.field),
+ ntpmsg.stratum,
+ exp2(ntpmsg.precision), ntpmsg.precision,
+ root_distance,
+ 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) {
+ m->sync = true;
+ r = manager_adjust_clock(m, offset, leap_sec);
+ if (r < 0)
+ log_error_errno(r, "Failed to call clock_adjtime(): %m");
+ }
+
+ log_debug("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+ippm%s",
+ m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_ppm,
+ spike ? " (ignored)" : "");
+
+ if (!m->good) {
+ _cleanup_free_ char *pretty = NULL;
+
+ m->good = true;
+
+ server_address_pretty(m->current_server_address, &pretty);
+ log_info("Synchronized to time server %s (%s).", strna(pretty), m->current_server_name->string);
+ sd_notifyf(false, "STATUS=Synchronized to time server %s (%s).", strna(pretty), m->current_server_name->string);
+ }
+
+ r = manager_arm_timer(m, m->poll_interval_usec);
+ if (r < 0)
+ return log_error_errno(r, "Failed to rearm timer: %m");
+
+ 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);
+
+ if (m->server_socket >= 0)
+ return 0;
+
+ assert(!m->event_receive);
+ assert(m->current_server_address);
+
+ addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
+
+ m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
+ if (m->server_socket < 0)
+ return -errno;
+
+ r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
+ if (r < 0)
+ return -errno;
+
+ r = setsockopt(m->server_socket, SOL_SOCKET, SO_TIMESTAMPNS, &on, sizeof(on));
+ if (r < 0)
+ return -errno;
+
+ (void) setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
+
+ return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
+}
+
+static void manager_listen_stop(Manager *m) {
+ assert(m);
+
+ m->event_receive = sd_event_source_unref(m->event_receive);
+ m->server_socket = safe_close(m->server_socket);
+}
+
+static int manager_begin(Manager *m) {
+ _cleanup_free_ char *pretty = NULL;
+ int r;
+
+ assert(m);
+ assert_return(m->current_server_name, -EHOSTUNREACH);
+ assert_return(m->current_server_address, -EHOSTUNREACH);
+
+ m->good = false;
+ m->missed_replies = NTP_MAX_MISSED_REPLIES;
+ if (m->poll_interval_usec == 0)
+ m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
+
+ server_address_pretty(m->current_server_address, &pretty);
+ log_debug("Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
+ sd_notifyf(false, "STATUS=Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
+
+ r = manager_clock_watch_setup(m);
+ if (r < 0)
+ return r;
+
+ return manager_send_request(m);
+}
+
+void manager_set_server_name(Manager *m, ServerName *n) {
+ assert(m);
+
+ if (m->current_server_name == n)
+ return;
+
+ m->current_server_name = n;
+ m->current_server_address = NULL;
+
+ manager_disconnect(m);
+
+ if (n)
+ log_debug("Selected server %s.", n->string);
+}
+
+void manager_set_server_address(Manager *m, ServerAddress *a) {
+ assert(m);
+
+ if (m->current_server_address == a)
+ return;
+
+ m->current_server_address = a;
+ /* If a is NULL, we are just clearing the address, without
+ * changing the name. Keep the existing name in that case. */
+ if (a)
+ m->current_server_name = a->name;
+
+ manager_disconnect(m);
+
+ if (a) {
+ _cleanup_free_ char *pretty = NULL;
+ server_address_pretty(a, &pretty);
+ log_debug("Selected address %s of server %s.", strna(pretty), a->name->string);
+ }
+}
+
+static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) {
+ Manager *m = userdata;
+ int r;
+
+ assert(q);
+ assert(m);
+ assert(m->current_server_name);
+
+ m->resolve_query = sd_resolve_query_unref(m->resolve_query);
+
+ if (ret != 0) {
+ log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
+
+ /* Try next host */
+ return manager_connect(m);
+ }
+
+ for (; ai; ai = ai->ai_next) {
+ _cleanup_free_ char *pretty = NULL;
+ ServerAddress *a;
+
+ assert(ai->ai_addr);
+ assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
+
+ if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
+ log_warning("Unsuitable address protocol for %s", m->current_server_name->string);
+ continue;
+ }
+
+ r = server_address_new(m->current_server_name, &a, (const union sockaddr_union*) ai->ai_addr, ai->ai_addrlen);
+ if (r < 0)
+ return log_error_errno(r, "Failed to add server address: %m");
+
+ server_address_pretty(a, &pretty);
+ log_debug("Resolved address %s for %s.", pretty, m->current_server_name->string);
+ }
+
+ if (!m->current_server_name->addresses) {
+ log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
+
+ /* Try next host */
+ return manager_connect(m);
+ }
+
+ manager_set_server_address(m, m->current_server_name->addresses);
+
+ return manager_begin(m);
+}
+
+static int manager_retry_connect(sd_event_source *source, usec_t usec, void *userdata) {
+ Manager *m = userdata;
+
+ assert(m);
+
+ return manager_connect(m);
+}
+
+int manager_connect(Manager *m) {
+ int r;
+
+ assert(m);
+
+ manager_disconnect(m);
+
+ m->event_retry = sd_event_source_unref(m->event_retry);
+ if (!ratelimit_test(&m->ratelimit)) {
+ log_debug("Slowing down attempts to contact servers.");
+
+ r = sd_event_add_time(m->event, &m->event_retry, clock_boottime_or_monotonic(), now(clock_boottime_or_monotonic()) + RETRY_USEC, 0, manager_retry_connect, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create retry timer: %m");
+
+ return 0;
+ }
+
+ /* If we already are operating on some address, switch to the
+ * next one. */
+ if (m->current_server_address && m->current_server_address->addresses_next)
+ manager_set_server_address(m, m->current_server_address->addresses_next);
+ else {
+ struct addrinfo hints = {
+ .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
+ .ai_socktype = SOCK_DGRAM,
+ };
+
+ /* Hmm, we are through all addresses, let's look for the next host instead */
+ if (m->current_server_name && m->current_server_name->names_next)
+ manager_set_server_name(m, m->current_server_name->names_next);
+ else {
+ ServerName *f;
+ bool restart = true;
+
+ /* Our current server name list is exhausted,
+ * let's find the next one to iterate. First
+ * we try the system list, then the link list.
+ * After having processed the link list we
+ * jump back to the system list. However, if
+ * both lists are empty, we change to the
+ * fallback list. */
+ if (!m->current_server_name || m->current_server_name->type == SERVER_LINK) {
+ f = m->system_servers;
+ if (!f)
+ f = m->link_servers;
+ } else {
+ f = m->link_servers;
+ if (!f)
+ f = m->system_servers;
+ else
+ restart = false;
+ }
+
+ if (!f)
+ f = m->fallback_servers;
+
+ if (!f) {
+ manager_set_server_name(m, NULL);
+ log_debug("No server found.");
+ return 0;
+ }
+
+ if (restart && !m->exhausted_servers && m->poll_interval_usec) {
+ log_debug("Waiting after exhausting servers.");
+ r = sd_event_add_time(m->event, &m->event_retry, clock_boottime_or_monotonic(), now(clock_boottime_or_monotonic()) + m->poll_interval_usec, 0, manager_retry_connect, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create retry timer: %m");
+
+ m->exhausted_servers = true;
+
+ /* Increase the polling interval */
+ if (m->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
+ m->poll_interval_usec *= 2;
+
+ return 0;
+ }
+
+ m->exhausted_servers = false;
+
+ manager_set_server_name(m, f);
+ }
+
+ /* Tell the resolver to reread /etc/resolv.conf, in
+ * case it changed. */
+ res_init();
+
+ /* Flush out any previously resolved addresses */
+ server_name_flush_addresses(m->current_server_name);
+
+ log_debug("Resolving %s...", m->current_server_name->string);
+
+ r = sd_resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create resolver: %m");
+
+ return 1;
+ }
+
+ r = manager_begin(m);
+ if (r < 0)
+ return r;
+
+ return 1;
+}
+
+void manager_disconnect(Manager *m) {
+ assert(m);
+
+ m->resolve_query = sd_resolve_query_unref(m->resolve_query);
+
+ m->event_timer = sd_event_source_unref(m->event_timer);
+
+ manager_listen_stop(m);
+
+ m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
+ m->clock_watch_fd = safe_close(m->clock_watch_fd);
+
+ m->event_timeout = sd_event_source_unref(m->event_timeout);
+
+ sd_notifyf(false, "STATUS=Idle.");
+}
+
+void manager_flush_server_names(Manager *m, ServerType t) {
+ assert(m);
+
+ if (t == SERVER_SYSTEM)
+ while (m->system_servers)
+ server_name_free(m->system_servers);
+
+ if (t == SERVER_LINK)
+ while (m->link_servers)
+ server_name_free(m->link_servers);
+
+ if (t == SERVER_FALLBACK)
+ while (m->fallback_servers)
+ server_name_free(m->fallback_servers);
+}
+
+void manager_free(Manager *m) {
+ if (!m)
+ return;
+
+ manager_disconnect(m);
+ manager_flush_server_names(m, SERVER_SYSTEM);
+ manager_flush_server_names(m, SERVER_LINK);
+ manager_flush_server_names(m, SERVER_FALLBACK);
+
+ sd_event_source_unref(m->event_retry);
+
+ sd_event_source_unref(m->network_event_source);
+ sd_network_monitor_unref(m->network_monitor);
+
+ sd_resolve_unref(m->resolve);
+ sd_event_unref(m->event);
+
+ free(m);
+}
+
+static int manager_network_read_link_servers(Manager *m) {
+ _cleanup_strv_free_ char **ntp = NULL;
+ ServerName *n, *nx;
+ char **i;
+ int r;
+
+ assert(m);
+
+ r = sd_network_get_ntp(&ntp);
+ if (r < 0)
+ goto clear;
+
+ LIST_FOREACH(names, n, m->link_servers)
+ n->marked = true;
+
+ STRV_FOREACH(i, ntp) {
+ bool found = false;
+
+ LIST_FOREACH(names, n, m->link_servers)
+ if (streq(n->string, *i)) {
+ n->marked = false;
+ found = true;
+ break;
+ }
+
+ if (!found) {
+ r = server_name_new(m, NULL, SERVER_LINK, *i);
+ if (r < 0)
+ goto clear;
+ }
+ }
+
+ LIST_FOREACH_SAFE(names, n, nx, m->link_servers)
+ if (n->marked)
+ server_name_free(n);
+
+ return 0;
+
+clear:
+ manager_flush_server_names(m, SERVER_LINK);
+ return r;
+}
+
+static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+ Manager *m = userdata;
+ bool connected, online;
+ int r;
+
+ assert(m);
+
+ sd_network_monitor_flush(m->network_monitor);
+
+ manager_network_read_link_servers(m);
+
+ /* check if the machine is online */
+ online = network_is_online();
+
+ /* check if the client is currently connected */
+ connected = m->server_socket >= 0 || m->resolve_query || m->exhausted_servers;
+
+ if (connected && !online) {
+ log_info("No network connectivity, watching for changes.");
+ manager_disconnect(m);
+
+ } else if (!connected && online) {
+ log_info("Network configuration changed, trying to establish connection.");
+
+ if (m->current_server_address)
+ r = manager_begin(m);
+ else
+ r = manager_connect(m);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int manager_network_monitor_listen(Manager *m) {
+ int r, fd, events;
+
+ assert(m);
+
+ r = sd_network_monitor_new(&m->network_monitor, NULL);
+ if (r < 0)
+ return r;
+
+ fd = sd_network_monitor_get_fd(m->network_monitor);
+ if (fd < 0)
+ return fd;
+
+ events = sd_network_monitor_get_events(m->network_monitor);
+ if (events < 0)
+ return events;
+
+ r = sd_event_add_io(m->event, &m->network_event_source, fd, events, manager_network_event_handler, m);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int manager_new(Manager **ret) {
+ _cleanup_(manager_freep) Manager *m = NULL;
+ int r;
+
+ assert(ret);
+
+ m = new0(Manager, 1);
+ if (!m)
+ return -ENOMEM;
+
+ m->server_socket = m->clock_watch_fd = -1;
+
+ RATELIMIT_INIT(m->ratelimit, RATELIMIT_INTERVAL_USEC, RATELIMIT_BURST);
+
+ r = manager_parse_server_string(m, SERVER_FALLBACK, NTP_SERVERS);
+ if (r < 0)
+ return r;
+
+ r = sd_event_default(&m->event);
+ if (r < 0)
+ return r;
+
+ sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
+ sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
+
+ sd_event_set_watchdog(m->event, true);
+
+ r = sd_resolve_default(&m->resolve);
+ if (r < 0)
+ return r;
+
+ r = sd_resolve_attach_event(m->resolve, m->event, 0);
+ if (r < 0)
+ return r;
+
+ r = manager_network_monitor_listen(m);
+ if (r < 0)
+ return r;
+
+ manager_network_read_link_servers(m);
+
+ *ret = m;
+ m = NULL;
+
+ return 0;
+}