1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2014 Kay Sievers, Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
29 #include <arpa/inet.h>
30 #include <netinet/in.h>
31 #include <netinet/ip.h>
32 #include <sys/timerfd.h>
33 #include <sys/timex.h>
34 #include <sys/socket.h>
36 #include <sys/prctl.h>
37 #include <sys/types.h>
42 #include "sparse-endian.h"
44 #include "socket-util.h"
46 #include "ratelimit.h"
48 #include "conf-parser.h"
50 #include "sd-resolve.h"
51 #include "sd-daemon.h"
52 #include "sd-network.h"
53 #include "event-util.h"
54 #include "network-util.h"
55 #include "clock-util.h"
56 #include "capability.h"
58 #include "timesyncd.h"
60 #define TIME_T_MAX (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
63 #define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
66 /* expected accuracy of time synchronization; used to adjust the poll interval */
67 #define NTP_ACCURACY_SEC 0.2
70 * "A client MUST NOT under any conditions use a poll interval less
73 #define NTP_POLL_INTERVAL_MIN_SEC 32
74 #define NTP_POLL_INTERVAL_MAX_SEC 2048
77 * Maximum delta in seconds which the system clock is gradually adjusted
78 * (slew) to approach the network time. Deltas larger that this are set by
79 * letting the system time jump. The kernel's limit for adjtime is 0.5s.
81 #define NTP_MAX_ADJUST 0.4
83 /* NTP protocol, packet header */
84 #define NTP_LEAP_PLUSSEC 1
85 #define NTP_LEAP_MINUSSEC 2
86 #define NTP_LEAP_NOTINSYNC 3
87 #define NTP_MODE_CLIENT 3
88 #define NTP_MODE_SERVER 4
89 #define NTP_FIELD_LEAP(f) (((f) >> 6) & 3)
90 #define NTP_FIELD_VERSION(f) (((f) >> 3) & 7)
91 #define NTP_FIELD_MODE(f) ((f) & 7)
92 #define NTP_FIELD(l, v, m) (((l) << 6) | ((v) << 3) | (m))
95 * "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
96 * in seconds relative to 0h on 1 January 1900."
98 #define OFFSET_1900_1970 2208988800UL
100 #define RETRY_USEC (30*USEC_PER_SEC)
101 #define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
102 #define RATELIMIT_BURST 10
104 #define TIMEOUT_USEC (10*USEC_PER_SEC)
111 struct ntp_ts_short {
121 struct ntp_ts_short root_delay;
122 struct ntp_ts_short root_dispersion;
124 struct ntp_ts reference_time;
125 struct ntp_ts origin_time;
126 struct ntp_ts recv_time;
127 struct ntp_ts trans_time;
130 static void manager_free(Manager *m);
131 DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free);
132 #define _cleanup_manager_free_ _cleanup_(manager_freep)
134 static int manager_arm_timer(Manager *m, usec_t next);
135 static int manager_clock_watch_setup(Manager *m);
136 static int manager_connect(Manager *m);
137 static void manager_disconnect(Manager *m);
139 static double ntp_ts_to_d(const struct ntp_ts *ts) {
140 return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
143 static double ts_to_d(const struct timespec *ts) {
144 return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
147 static double tv_to_d(const struct timeval *tv) {
148 return tv->tv_sec + (1.0e-6 * tv->tv_usec);
151 static double square(double d) {
155 static int load_clock_timestamp(uid_t uid, gid_t gid) {
156 _cleanup_close_ int fd = -1;
157 usec_t min = TIME_EPOCH * USEC_PER_SEC;
161 /* Let's try to make sure that the clock is always
162 * monotonically increasing, by saving the clock whenever we
163 * have a new NTP time, or when we shut down, and restoring it
164 * when we start again. This is particularly helpful on
165 * systems lacking a battery backed RTC. We also will adjust
166 * the time to at least the build time of systemd. */
168 fd = open("/var/lib/systemd/clock", O_RDWR|O_CLOEXEC, 0644);
173 /* check if the recorded time is later than the compiled-in one */
176 stamp = timespec_load(&st.st_mtim);
181 /* Try to fix the access mode, so that we can still
182 touch the file after dropping priviliges */
184 fchown(fd, uid, gid);
187 /* create stamp file with the compiled-in date */
188 touch_file("/var/lib/systemd/clock", true, min, uid, gid, 0644);
190 ct = now(CLOCK_REALTIME);
193 char date[FORMAT_TIMESTAMP_MAX];
195 log_info("System clock time unset or jumped backwards, restoring from recorded timestamp: %s",
196 format_timestamp(date, sizeof(date), min));
198 if (clock_settime(CLOCK_REALTIME, timespec_store(&ts, min)) < 0)
199 log_error("Failed to restore system clock: %m");
205 static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
206 _cleanup_free_ char *pretty = NULL;
207 Manager *m = userdata;
210 assert(m->current_server_name);
211 assert(m->current_server_address);
213 server_address_pretty(m->current_server_address, &pretty);
214 log_info("Timed out waiting for reply from %s (%s).", strna(pretty), m->current_server_name->string);
216 return manager_connect(m);
219 static int manager_send_request(Manager *m) {
220 _cleanup_free_ char *pretty = NULL;
221 struct ntp_msg ntpmsg = {
223 * "The client initializes the NTP message header, sends the request
224 * to the server, and strips the time of day from the Transmit
225 * Timestamp field of the reply. For this purpose, all the NTP
226 * header fields are set to 0, except the Mode, VN, and optional
227 * Transmit Timestamp fields."
229 .field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
235 assert(m->current_server_name);
236 assert(m->current_server_address);
238 m->event_timeout = sd_event_source_unref(m->event_timeout);
241 * Set transmit timestamp, remember it; the server will send that back
242 * as the origin timestamp and we have an indication that this is the
243 * matching answer to our request.
245 * The actual value does not matter, We do not care about the correct
246 * NTP UINT_MAX fraction; we just pass the plain nanosecond value.
248 assert_se(clock_gettime(CLOCK_MONOTONIC, &m->trans_time_mon) >= 0);
249 assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
250 ntpmsg.trans_time.sec = htobe32(m->trans_time.tv_sec + OFFSET_1900_1970);
251 ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
253 server_address_pretty(m->current_server_address, &pretty);
255 len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
256 if (len == sizeof(ntpmsg)) {
258 log_debug("Sent NTP request to %s (%s).", strna(pretty), m->current_server_name->string);
260 log_debug("Sending NTP request to %s (%s) failed: %m", strna(pretty), m->current_server_name->string);
261 return manager_connect(m);
264 /* re-arm timer with increasing timeout, in case the packets never arrive back */
265 if (m->retry_interval > 0) {
266 if (m->retry_interval < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
267 m->retry_interval *= 2;
269 m->retry_interval = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
271 r = manager_arm_timer(m, m->retry_interval);
273 log_error("Failed to rearm timer: %s", strerror(-r));
277 r = sd_event_add_time(
281 now(CLOCK_MONOTONIC) + TIMEOUT_USEC, 0,
284 log_error("Failed to arm timeout timer: %s", strerror(-r));
291 static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
292 Manager *m = userdata;
296 return manager_send_request(m);
299 static int manager_arm_timer(Manager *m, usec_t next) {
303 assert(m->event_receive);
306 m->event_timer = sd_event_source_unref(m->event_timer);
310 if (m->event_timer) {
311 r = sd_event_source_set_time(m->event_timer, now(CLOCK_MONOTONIC) + next);
315 return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
318 return sd_event_add_time(
322 now(CLOCK_MONOTONIC) + next, 0,
326 static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
327 Manager *m = userdata;
332 manager_clock_watch_setup(m);
334 /* skip our own jumps */
341 log_info("System time changed. Resyncing.");
342 m->poll_resync = true;
343 return manager_send_request(m);
346 /* wake up when the system time changes underneath us */
347 static int manager_clock_watch_setup(Manager *m) {
349 struct itimerspec its = {
350 .it_value.tv_sec = TIME_T_MAX
357 m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
358 safe_close(m->clock_watch_fd);
360 m->clock_watch_fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
361 if (m->clock_watch_fd < 0) {
362 log_error("Failed to create timerfd: %m");
366 if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0) {
367 log_error("Failed to set up timerfd: %m");
371 r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, manager_clock_watch, m);
373 log_error("Failed to create clock watch event source: %s", strerror(-r));
380 static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
381 struct timex tmx = {};
387 * For small deltas, tell the kernel to gradually adjust the system
388 * clock to the NTP time, larger deltas are just directly set.
390 if (fabs(offset) < NTP_MAX_ADJUST) {
391 tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR;
392 tmx.status = STA_PLL;
393 tmx.offset = offset * NSEC_PER_SEC;
394 tmx.constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4;
397 log_debug(" adjust (slew): %+.3f sec\n", offset);
399 tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET;
401 /* ADJ_NANO uses nanoseconds in the microseconds field */
402 tmx.time.tv_sec = (long)offset;
403 tmx.time.tv_usec = (offset - tmx.time.tv_sec) * NSEC_PER_SEC;
405 /* the kernel expects -0.3s as {-1, 7000.000.000} */
406 if (tmx.time.tv_usec < 0) {
407 tmx.time.tv_sec -= 1;
408 tmx.time.tv_usec += NSEC_PER_SEC;
412 log_debug(" adjust (jump): %+.3f sec\n", offset);
416 * An unset STA_UNSYNC will enable the kernel's 11-minute mode,
417 * which syncs the system time periodically to the RTC.
419 * In case the RTC runs in local time, never touch the RTC,
420 * we have no way to properly handle daylight saving changes and
421 * mobile devices moving between time zones.
423 if (m->rtc_local_time)
424 tmx.status |= STA_UNSYNC;
428 tmx.status |= STA_INS;
431 tmx.status |= STA_DEL;
435 r = clock_adjtime(CLOCK_REALTIME, &tmx);
439 touch("/var/lib/systemd/clock");
441 m->drift_ppm = tmx.freq / 65536;
443 log_debug(" status : %04i %s\n"
444 " time now : %li.%03llu\n"
446 " offset : %+.3f sec\n"
447 " freq offset : %+li (%i ppm)\n",
448 tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
449 tmx.time.tv_sec, (unsigned long long) (tmx.time.tv_usec / NSEC_PER_MSEC),
451 (double)tmx.offset / NSEC_PER_SEC,
452 tmx.freq, m->drift_ppm);
457 static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
458 unsigned int i, idx_cur, idx_new, idx_min;
466 /* ignore initial sample */
467 if (m->packet_count == 1)
470 /* store the current data in our samples array */
471 idx_cur = m->samples_idx;
472 idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
473 m->samples_idx = idx_new;
474 m->samples[idx_new].offset = offset;
475 m->samples[idx_new].delay = delay;
477 /* calculate new jitter value from the RMS differences relative to the lowest delay sample */
478 jitter = m->samples_jitter;
479 for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
480 if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
484 for (i = 0; i < ELEMENTSOF(m->samples); i++)
485 j += square(m->samples[i].offset - m->samples[idx_min].offset);
486 m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
488 /* ignore samples when resyncing */
492 /* always accept offset if we are farther off than the round-trip delay */
493 if (fabs(offset) > delay)
496 /* we need a few samples before looking at them */
497 if (m->packet_count < 4)
500 /* do not accept anything worse than the maximum possible error of the best sample */
501 if (fabs(offset) > m->samples[idx_min].delay)
504 /* compare the difference between the current offset to the previous offset and jitter */
505 return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
508 static void manager_adjust_poll(Manager *m, double offset, bool spike) {
511 if (m->poll_resync) {
512 m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
513 m->poll_resync = false;
517 /* set to minimal poll interval */
518 if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
519 m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
523 /* increase polling interval */
524 if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
525 if (m->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
526 m->poll_interval_usec *= 2;
530 /* decrease polling interval */
531 if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
532 if (m->poll_interval_usec > NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC)
533 m->poll_interval_usec /= 2;
538 static bool sockaddr_equal(union sockaddr_union *a, union sockaddr_union *b) {
542 if (a->sa.sa_family != b->sa.sa_family)
545 if (a->sa.sa_family == AF_INET)
546 return a->in.sin_addr.s_addr == b->in.sin_addr.s_addr;
548 if (a->sa.sa_family == AF_INET6)
549 return memcmp(&a->in6.sin6_addr, &b->in6.sin6_addr, sizeof(a->in6.sin6_addr)) == 0;
554 static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
555 Manager *m = userdata;
556 struct ntp_msg ntpmsg;
560 .iov_len = sizeof(ntpmsg),
563 struct cmsghdr cmsghdr;
564 uint8_t buf[CMSG_SPACE(sizeof(struct timeval))];
566 union sockaddr_union server_addr;
567 struct msghdr msghdr = {
570 .msg_control = &control,
571 .msg_controllen = sizeof(control),
572 .msg_name = &server_addr,
573 .msg_namelen = sizeof(server_addr),
575 struct cmsghdr *cmsg;
576 struct timespec now_ts;
577 struct timeval *recv_time;
579 double origin, receive, trans, dest;
580 double delay, offset;
588 if (revents & (EPOLLHUP|EPOLLERR)) {
589 log_warning("Server connection returned error.");
590 return manager_connect(m);
593 len = recvmsg(fd, &msghdr, MSG_DONTWAIT);
598 log_warning("Error receiving message. Disconnecting.");
599 return manager_connect(m);
602 if (iov.iov_len < sizeof(struct ntp_msg)) {
603 log_warning("Invalid response from server. Disconnecting.");
604 return manager_connect(m);
607 if (!m->current_server_name ||
608 !m->current_server_address ||
609 !sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
610 log_debug("Response from unknown server.");
615 for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {
616 if (cmsg->cmsg_level != SOL_SOCKET)
619 switch (cmsg->cmsg_type) {
621 recv_time = (struct timeval *) CMSG_DATA(cmsg);
626 log_error("Invalid packet timestamp.");
631 log_debug("Unexpected reply. Ignoring.");
635 /* check our "time cookie" (we just stored nanoseconds in the fraction field) */
636 if (be32toh(ntpmsg.origin_time.sec) != m->trans_time.tv_sec + OFFSET_1900_1970 ||
637 be32toh(ntpmsg.origin_time.frac) != m->trans_time.tv_nsec) {
638 log_debug("Invalid reply; not our transmit time. Ignoring.");
642 m->event_timeout = sd_event_source_unref(m->event_timeout);
644 if (be32toh(ntpmsg.recv_time.sec) < TIME_EPOCH + OFFSET_1900_1970 ||
645 be32toh(ntpmsg.trans_time.sec) < TIME_EPOCH + OFFSET_1900_1970) {
646 log_debug("Invalid reply, returned times before epoch. Ignoring.");
647 return manager_connect(m);
650 if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC) {
651 log_debug("Server is not synchronized. Disconnecting.");
652 return manager_connect(m);
655 if (!IN_SET(NTP_FIELD_VERSION(ntpmsg.field), 3, 4)) {
656 log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
657 return manager_connect(m);
660 if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
661 log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
662 return manager_connect(m);
667 m->retry_interval = 0;
669 /* announce leap seconds */
670 if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
672 else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
678 * "Timestamp Name ID When Generated
679 * ------------------------------------------------------------
680 * Originate Timestamp T1 time request sent by client
681 * Receive Timestamp T2 time request received by server
682 * Transmit Timestamp T3 time reply sent by server
683 * Destination Timestamp T4 time reply received by client
685 * The round-trip delay, d, and system clock offset, t, are defined as:
686 * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
688 assert_se(clock_gettime(CLOCK_MONOTONIC, &now_ts) >= 0);
689 origin = tv_to_d(recv_time) - (ts_to_d(&now_ts) - ts_to_d(&m->trans_time_mon)) + OFFSET_1900_1970;
690 receive = ntp_ts_to_d(&ntpmsg.recv_time);
691 trans = ntp_ts_to_d(&ntpmsg.trans_time);
692 dest = tv_to_d(recv_time) + OFFSET_1900_1970;
694 offset = ((receive - origin) + (trans - dest)) / 2;
695 delay = (dest - origin) - (trans - receive);
697 spike = manager_sample_spike_detection(m, offset, delay);
699 manager_adjust_poll(m, offset, spike);
701 log_debug("NTP response:\n"
706 " precision : %.6f sec (%d)\n"
707 " reference : %.4s\n"
712 " offset : %+.3f sec\n"
713 " delay : %+.3f sec\n"
714 " packet count : %"PRIu64"\n"
716 " poll interval: " USEC_FMT "\n",
717 NTP_FIELD_LEAP(ntpmsg.field),
718 NTP_FIELD_VERSION(ntpmsg.field),
719 NTP_FIELD_MODE(ntpmsg.field),
721 exp2(ntpmsg.precision), ntpmsg.precision,
722 ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
723 origin - OFFSET_1900_1970,
724 receive - OFFSET_1900_1970,
725 trans - OFFSET_1900_1970,
726 dest - OFFSET_1900_1970,
729 m->samples_jitter, spike ? " spike" : "",
730 m->poll_interval_usec / USEC_PER_SEC);
734 r = manager_adjust_clock(m, offset, leap_sec);
736 log_error("Failed to call clock_adjtime(): %m");
739 log_info("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+ippm%s",
740 m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_ppm,
741 spike ? " (ignored)" : "");
743 r = manager_arm_timer(m, m->poll_interval_usec);
745 log_error("Failed to rearm timer: %s", strerror(-r));
752 static int manager_listen_setup(Manager *m) {
753 union sockaddr_union addr = {};
754 static const int tos = IPTOS_LOWDELAY;
755 static const int on = 1;
760 assert(m->server_socket < 0);
761 assert(!m->event_receive);
762 assert(m->current_server_address);
764 addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
766 m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
767 if (m->server_socket < 0)
770 r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
774 r = setsockopt(m->server_socket, SOL_SOCKET, SO_TIMESTAMP, &on, sizeof(on));
778 setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
780 return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
783 static int manager_begin(Manager *m) {
784 _cleanup_free_ char *pretty = NULL;
788 assert_return(m->current_server_name, -EHOSTUNREACH);
789 assert_return(m->current_server_address, -EHOSTUNREACH);
791 m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
793 server_address_pretty(m->current_server_address, &pretty);
794 log_info("Using NTP server %s (%s).", strna(pretty), m->current_server_name->string);
795 sd_notifyf(false, "STATUS=Using Time Server %s (%s).", strna(pretty), m->current_server_name->string);
797 r = manager_listen_setup(m);
799 log_warning("Failed to setup connection socket: %s", strerror(-r));
803 r = manager_clock_watch_setup(m);
807 return manager_send_request(m);
810 static void server_name_flush_addresses(ServerName *n) {
815 while ((a = n->addresses)) {
816 LIST_REMOVE(addresses, n->addresses, a);
821 static void manager_flush_names(Manager *m) {
826 while ((n = m->servers)) {
827 LIST_REMOVE(names, m->servers, n);
829 server_name_flush_addresses(n);
834 static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) {
835 Manager *m = userdata;
836 ServerAddress *a, *last = NULL;
840 assert(m->current_server_name);
842 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
845 log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
848 return manager_connect(m);
851 server_name_flush_addresses(m->current_server_name);
853 for (; ai; ai = ai->ai_next) {
854 _cleanup_free_ char *pretty = NULL;
857 assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
858 assert(ai->ai_addrlen <= sizeof(union sockaddr_union));
860 if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
861 log_warning("Unsuitable address protocol for %s", m->current_server_name->string);
865 a = new0(ServerAddress, 1);
869 memcpy(&a->sockaddr, ai->ai_addr, ai->ai_addrlen);
870 a->socklen = ai->ai_addrlen;
872 LIST_INSERT_AFTER(addresses, m->current_server_name->addresses, last, a);
875 sockaddr_pretty(&a->sockaddr.sa, a->socklen, true, &pretty);
876 log_debug("Resolved address %s for %s.", pretty, m->current_server_name->string);
879 if (!m->current_server_name->addresses) {
880 log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
883 return manager_connect(m);
886 m->current_server_address = m->current_server_name->addresses;
888 return manager_begin(m);
891 static int manager_retry(sd_event_source *source, usec_t usec, void *userdata) {
892 Manager *m = userdata;
896 return manager_connect(m);
899 static int manager_connect(Manager *m) {
901 struct addrinfo hints = {
902 .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
903 .ai_socktype = SOCK_DGRAM,
909 manager_disconnect(m);
911 m->event_retry = sd_event_source_unref(m->event_retry);
912 if (!ratelimit_test(&m->ratelimit)) {
913 log_debug("Slowing down attempts to contact servers.");
915 r = sd_event_add_time(m->event, &m->event_retry, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + RETRY_USEC, 0, manager_retry, m);
917 log_error("Failed to create retry timer: %s", strerror(-r));
924 /* If we already are operating on some address, switch to the
926 if (m->current_server_address && m->current_server_address->addresses_next)
927 m->current_server_address = m->current_server_address->addresses_next;
929 /* Hmm, we are through all addresses, let's look for the next host instead */
930 m->current_server_address = NULL;
932 if (m->current_server_name && m->current_server_name->names_next)
933 m->current_server_name = m->current_server_name->names_next;
936 m->current_server_name = NULL;
937 log_debug("No server found.");
941 m->current_server_name = m->servers;
944 /* Tell the resolver to reread /etc/resolv.conf, in
945 * case it changed. */
948 r = sd_resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, m);
950 log_error("Failed to create resolver: %s", strerror(-r));
957 r = manager_begin(m);
964 static int manager_add_server(Manager *m, const char *server) {
965 ServerName *n, *tail;
970 n = new0(ServerName, 1);
974 n->string = strdup(server);
980 LIST_FIND_TAIL(names, m->servers, tail);
981 LIST_INSERT_AFTER(names, m->servers, tail, n);
986 static int manager_add_server_string(Manager *m, const char *string) {
994 FOREACH_WORD_QUOTED(w, l, string, state) {
1000 r = manager_add_server(m, t);
1002 log_error("Failed to add server %s to configuration, ignoring: %s", t, strerror(-r));
1008 static void manager_disconnect(Manager *m) {
1011 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
1013 m->event_timer = sd_event_source_unref(m->event_timer);
1015 m->event_receive = sd_event_source_unref(m->event_receive);
1016 m->server_socket = safe_close(m->server_socket);
1018 m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
1019 m->clock_watch_fd = safe_close(m->clock_watch_fd);
1021 m->event_timeout = sd_event_source_unref(m->event_timeout);
1023 sd_notifyf(false, "STATUS=Idle.");
1026 static int manager_new(Manager **ret) {
1027 _cleanup_manager_free_ Manager *m = NULL;
1032 m = new0(Manager, 1);
1036 m->server_socket = m->clock_watch_fd = -1;
1038 RATELIMIT_INIT(m->ratelimit, RATELIMIT_INTERVAL_USEC, RATELIMIT_BURST);
1040 r = sd_event_default(&m->event);
1044 sd_event_set_watchdog(m->event, true);
1046 sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
1047 sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
1049 r = sd_resolve_default(&m->resolve);
1053 r = sd_resolve_attach_event(m->resolve, m->event, 0);
1063 static void manager_free(Manager *m) {
1067 manager_disconnect(m);
1068 manager_flush_names(m);
1070 sd_event_source_unref(m->event_retry);
1072 sd_event_source_unref(m->network_event_source);
1073 sd_network_monitor_unref(m->network_monitor);
1075 sd_resolve_unref(m->resolve);
1076 sd_event_unref(m->event);
1081 int config_parse_servers(
1083 const char *filename,
1085 const char *section,
1086 unsigned section_line,
1093 Manager *m = userdata;
1099 manager_flush_names(m);
1100 manager_add_server_string(m, rvalue);
1105 static int manager_parse_config_file(Manager *m) {
1106 return config_parse(NULL, "/etc/systemd/timesyncd.conf", NULL,
1108 config_item_perf_lookup, timesyncd_gperf_lookup,
1109 false, false, true, m);
1112 static bool network_is_online(void) {
1113 _cleanup_free_ char *state = NULL;
1116 r = sd_network_get_operational_state(&state);
1117 if (r >= 0 && STR_IN_SET(state, "routable", "degraded"))
1123 static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents,
1125 Manager *m = userdata;
1126 bool connected, online;
1131 /* check if the machine is online */
1132 online = network_is_online();
1134 /* check if the client is currently connected */
1135 connected = (m->server_socket != -1);
1137 if (connected && !online) {
1138 log_info("No network connectivity, watching for changes.");
1139 manager_disconnect(m);
1140 } else if (!connected && online) {
1141 log_info("Network configuration changed, trying to establish connection.");
1142 if (m->current_server_address) {
1143 r = manager_begin(m);
1147 r = manager_connect(m);
1153 sd_network_monitor_flush(m->network_monitor);
1158 static int manager_network_monitor_listen(Manager *m) {
1159 _cleanup_event_source_unref_ sd_event_source *event_source = NULL;
1160 _cleanup_network_monitor_unref_ sd_network_monitor *monitor = NULL;
1163 r = sd_network_monitor_new(&monitor, NULL);
1167 fd = sd_network_monitor_get_fd(monitor);
1171 events = sd_network_monitor_get_events(monitor);
1175 r = sd_event_add_io(m->event, &event_source, fd, events,
1176 &manager_network_event_handler, m);
1180 m->network_monitor = monitor;
1181 m->network_event_source = event_source;
1183 event_source = NULL;
1188 int main(int argc, char *argv[]) {
1189 const char *user = "systemd-timesync";
1190 _cleanup_manager_free_ Manager *m = NULL;
1196 log_error("This program does not take arguments.");
1197 return EXIT_FAILURE;
1200 log_set_target(LOG_TARGET_AUTO);
1201 log_set_facility(LOG_CRON);
1202 log_parse_environment();
1207 r = get_user_creds(&user, &uid, &gid, NULL, NULL);
1209 log_error("Cannot resolve user name %s: %s", user, strerror(-r));
1213 r = load_clock_timestamp(uid, gid);
1217 r = drop_privileges(uid, gid, (1ULL << CAP_SYS_TIME));
1221 assert_se(sigprocmask_many(SIG_BLOCK, SIGTERM, SIGINT, -1) == 0);
1223 r = manager_new(&m);
1225 log_error("Failed to allocate manager: %s", strerror(-r));
1229 if (clock_is_localtime() > 0) {
1230 log_info("The system is configured to read the RTC time in the local time zone. "
1231 "This mode can not be fully supported. All system time to RTC updates are disabled.");
1232 m->rtc_local_time = true;
1235 manager_add_server_string(m, NTP_SERVERS);
1236 manager_parse_config_file(m);
1238 r = manager_network_monitor_listen(m);
1240 log_error("Failed to listen to networkd events: %s", strerror(-r));
1244 log_debug("systemd-timesyncd running as pid %lu", (unsigned long) getpid());
1245 sd_notify(false, "READY=1");
1247 if (network_is_online()) {
1248 r = manager_connect(m);
1253 r = sd_event_loop(m->event);
1255 log_error("Failed to run event loop: %s", strerror(-r));
1259 sd_event_get_exit_code(m->event, &r);
1261 /* if we got an authoritative time, store it in the file system */
1263 touch("/var/lib/systemd/clock");
1266 sd_notify(false, "STATUS=Shutting down...");
1268 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;