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"
49 #include "sd-daemon.h"
50 #include "event-util.h"
51 #include "network-util.h"
52 #include "clock-util.h"
53 #include "capability.h"
55 #include "timesyncd-conf.h"
56 #include "timesyncd-manager.h"
57 #include "time-util.h"
60 #define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
63 /* expected accuracy of time synchronization; used to adjust the poll interval */
64 #define NTP_ACCURACY_SEC 0.2
67 * "A client MUST NOT under any conditions use a poll interval less
70 #define NTP_POLL_INTERVAL_MIN_SEC 32
71 #define NTP_POLL_INTERVAL_MAX_SEC 2048
74 * Maximum delta in seconds which the system clock is gradually adjusted
75 * (slew) to approach the network time. Deltas larger that this are set by
76 * letting the system time jump. The kernel's limit for adjtime is 0.5s.
78 #define NTP_MAX_ADJUST 0.4
80 /* NTP protocol, packet header */
81 #define NTP_LEAP_PLUSSEC 1
82 #define NTP_LEAP_MINUSSEC 2
83 #define NTP_LEAP_NOTINSYNC 3
84 #define NTP_MODE_CLIENT 3
85 #define NTP_MODE_SERVER 4
86 #define NTP_FIELD_LEAP(f) (((f) >> 6) & 3)
87 #define NTP_FIELD_VERSION(f) (((f) >> 3) & 7)
88 #define NTP_FIELD_MODE(f) ((f) & 7)
89 #define NTP_FIELD(l, v, m) (((l) << 6) | ((v) << 3) | (m))
91 /* Maximum acceptable root distance in seconds. */
92 #define NTP_MAX_ROOT_DISTANCE 5.0
94 /* Maximum number of missed replies before selecting another source. */
95 #define NTP_MAX_MISSED_REPLIES 2
98 * "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
99 * in seconds relative to 0h on 1 January 1900."
101 #define OFFSET_1900_1970 2208988800UL
103 #define RETRY_USEC (30*USEC_PER_SEC)
104 #define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
105 #define RATELIMIT_BURST 10
107 #define TIMEOUT_USEC (10*USEC_PER_SEC)
114 struct ntp_ts_short {
124 struct ntp_ts_short root_delay;
125 struct ntp_ts_short root_dispersion;
127 struct ntp_ts reference_time;
128 struct ntp_ts origin_time;
129 struct ntp_ts recv_time;
130 struct ntp_ts trans_time;
133 static int manager_arm_timer(Manager *m, usec_t next);
134 static int manager_clock_watch_setup(Manager *m);
135 static int manager_listen_setup(Manager *m);
136 static void manager_listen_stop(Manager *m);
138 static double ntp_ts_short_to_d(const struct ntp_ts_short *ts) {
139 return be16toh(ts->sec) + (be16toh(ts->frac) / 65536.0);
142 static double ntp_ts_to_d(const struct ntp_ts *ts) {
143 return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
146 static double ts_to_d(const struct timespec *ts) {
147 return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
150 static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
151 _cleanup_free_ char *pretty = NULL;
152 Manager *m = userdata;
155 assert(m->current_server_name);
156 assert(m->current_server_address);
158 server_address_pretty(m->current_server_address, &pretty);
159 log_info("Timed out waiting for reply from %s (%s).", strna(pretty), m->current_server_name->string);
161 return manager_connect(m);
164 static int manager_send_request(Manager *m) {
165 _cleanup_free_ char *pretty = NULL;
166 struct ntp_msg ntpmsg = {
168 * "The client initializes the NTP message header, sends the request
169 * to the server, and strips the time of day from the Transmit
170 * Timestamp field of the reply. For this purpose, all the NTP
171 * header fields are set to 0, except the Mode, VN, and optional
172 * Transmit Timestamp fields."
174 .field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
180 assert(m->current_server_name);
181 assert(m->current_server_address);
183 m->event_timeout = sd_event_source_unref(m->event_timeout);
185 r = manager_listen_setup(m);
187 return log_warning_errno(r, "Failed to setup connection socket: %m");
190 * Set transmit timestamp, remember it; the server will send that back
191 * as the origin timestamp and we have an indication that this is the
192 * matching answer to our request.
194 * The actual value does not matter, We do not care about the correct
195 * NTP UINT_MAX fraction; we just pass the plain nanosecond value.
197 assert_se(clock_gettime(clock_boottime_or_monotonic(), &m->trans_time_mon) >= 0);
198 assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
199 ntpmsg.trans_time.sec = htobe32(m->trans_time.tv_sec + OFFSET_1900_1970);
200 ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
202 server_address_pretty(m->current_server_address, &pretty);
204 len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
205 if (len == sizeof(ntpmsg)) {
207 log_debug("Sent NTP request to %s (%s).", strna(pretty), m->current_server_name->string);
209 log_debug_errno(errno, "Sending NTP request to %s (%s) failed: %m", strna(pretty), m->current_server_name->string);
210 return manager_connect(m);
213 /* re-arm timer with increasing timeout, in case the packets never arrive back */
214 if (m->retry_interval > 0) {
215 if (m->retry_interval < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
216 m->retry_interval *= 2;
218 m->retry_interval = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
220 r = manager_arm_timer(m, m->retry_interval);
222 return log_error_errno(r, "Failed to rearm timer: %m");
225 if (m->missed_replies > NTP_MAX_MISSED_REPLIES) {
226 r = sd_event_add_time(
229 clock_boottime_or_monotonic(),
230 now(clock_boottime_or_monotonic()) + TIMEOUT_USEC, 0,
233 return log_error_errno(r, "Failed to arm timeout timer: %m");
239 static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
240 Manager *m = userdata;
244 return manager_send_request(m);
247 static int manager_arm_timer(Manager *m, usec_t next) {
253 m->event_timer = sd_event_source_unref(m->event_timer);
257 if (m->event_timer) {
258 r = sd_event_source_set_time(m->event_timer, now(clock_boottime_or_monotonic()) + next);
262 return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
265 return sd_event_add_time(
268 clock_boottime_or_monotonic(),
269 now(clock_boottime_or_monotonic()) + next, 0,
273 static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
274 Manager *m = userdata;
279 manager_clock_watch_setup(m);
281 /* skip our own jumps */
288 log_info("System time changed. Resyncing.");
289 m->poll_resync = true;
291 return manager_send_request(m);
294 /* wake up when the system time changes underneath us */
295 static int manager_clock_watch_setup(Manager *m) {
297 struct itimerspec its = {
298 .it_value.tv_sec = TIME_T_MAX
305 m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
306 safe_close(m->clock_watch_fd);
308 m->clock_watch_fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
309 if (m->clock_watch_fd < 0)
310 return log_error_errno(errno, "Failed to create timerfd: %m");
312 if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0)
313 return log_error_errno(errno, "Failed to set up timerfd: %m");
315 r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, manager_clock_watch, m);
317 return log_error_errno(r, "Failed to create clock watch event source: %m");
322 static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
323 struct timex tmx = {};
329 * For small deltas, tell the kernel to gradually adjust the system
330 * clock to the NTP time, larger deltas are just directly set.
332 if (fabs(offset) < NTP_MAX_ADJUST) {
333 tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR;
334 tmx.status = STA_PLL;
335 tmx.offset = offset * NSEC_PER_SEC;
336 tmx.constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4;
339 log_debug(" adjust (slew): %+.3f sec", offset);
341 tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET;
343 /* ADJ_NANO uses nanoseconds in the microseconds field */
344 tmx.time.tv_sec = (long)offset;
345 tmx.time.tv_usec = (offset - tmx.time.tv_sec) * NSEC_PER_SEC;
347 /* the kernel expects -0.3s as {-1, 7000.000.000} */
348 if (tmx.time.tv_usec < 0) {
349 tmx.time.tv_sec -= 1;
350 tmx.time.tv_usec += NSEC_PER_SEC;
354 log_debug(" adjust (jump): %+.3f sec", offset);
358 * An unset STA_UNSYNC will enable the kernel's 11-minute mode,
359 * which syncs the system time periodically to the RTC.
361 * In case the RTC runs in local time, never touch the RTC,
362 * we have no way to properly handle daylight saving changes and
363 * mobile devices moving between time zones.
365 if (m->rtc_local_time)
366 tmx.status |= STA_UNSYNC;
370 tmx.status |= STA_INS;
373 tmx.status |= STA_DEL;
377 r = clock_adjtime(CLOCK_REALTIME, &tmx);
381 touch("/var/lib/systemd/clock");
383 m->drift_ppm = tmx.freq / 65536;
385 log_debug(" status : %04i %s\n"
386 " time now : %li.%03llu\n"
388 " offset : %+.3f sec\n"
389 " freq offset : %+li (%i ppm)\n",
390 tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
391 tmx.time.tv_sec, (unsigned long long) (tmx.time.tv_usec / NSEC_PER_MSEC),
393 (double)tmx.offset / NSEC_PER_SEC,
394 tmx.freq, m->drift_ppm);
399 static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
400 unsigned int i, idx_cur, idx_new, idx_min;
408 /* ignore initial sample */
409 if (m->packet_count == 1)
412 /* store the current data in our samples array */
413 idx_cur = m->samples_idx;
414 idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
415 m->samples_idx = idx_new;
416 m->samples[idx_new].offset = offset;
417 m->samples[idx_new].delay = delay;
419 /* calculate new jitter value from the RMS differences relative to the lowest delay sample */
420 jitter = m->samples_jitter;
421 for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
422 if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
426 for (i = 0; i < ELEMENTSOF(m->samples); i++)
427 j += pow(m->samples[i].offset - m->samples[idx_min].offset, 2);
428 m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
430 /* ignore samples when resyncing */
434 /* always accept offset if we are farther off than the round-trip delay */
435 if (fabs(offset) > delay)
438 /* we need a few samples before looking at them */
439 if (m->packet_count < 4)
442 /* do not accept anything worse than the maximum possible error of the best sample */
443 if (fabs(offset) > m->samples[idx_min].delay)
446 /* compare the difference between the current offset to the previous offset and jitter */
447 return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
450 static void manager_adjust_poll(Manager *m, double offset, bool spike) {
453 if (m->poll_resync) {
454 m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
455 m->poll_resync = false;
459 /* set to minimal poll interval */
460 if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
461 m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
465 /* increase polling interval */
466 if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
467 if (m->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
468 m->poll_interval_usec *= 2;
472 /* decrease polling interval */
473 if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
474 if (m->poll_interval_usec > NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC)
475 m->poll_interval_usec /= 2;
480 static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
481 Manager *m = userdata;
482 struct ntp_msg ntpmsg;
486 .iov_len = sizeof(ntpmsg),
489 struct cmsghdr cmsghdr;
490 uint8_t buf[CMSG_SPACE(sizeof(struct timeval))];
492 union sockaddr_union server_addr;
493 struct msghdr msghdr = {
496 .msg_control = &control,
497 .msg_controllen = sizeof(control),
498 .msg_name = &server_addr,
499 .msg_namelen = sizeof(server_addr),
501 struct cmsghdr *cmsg;
502 struct timespec *recv_time;
504 double origin, receive, trans, dest;
505 double delay, offset;
506 double root_distance;
514 if (revents & (EPOLLHUP|EPOLLERR)) {
515 log_warning("Server connection returned error.");
516 return manager_connect(m);
519 len = recvmsg(fd, &msghdr, MSG_DONTWAIT);
524 log_warning("Error receiving message. Disconnecting.");
525 return manager_connect(m);
528 /* Too short or too long packet? */
529 if (iov.iov_len < sizeof(struct ntp_msg) || (msghdr.msg_flags & MSG_TRUNC)) {
530 log_warning("Invalid response from server. Disconnecting.");
531 return manager_connect(m);
534 if (!m->current_server_name ||
535 !m->current_server_address ||
536 !sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
537 log_debug("Response from unknown server.");
542 for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {
543 if (cmsg->cmsg_level != SOL_SOCKET)
546 switch (cmsg->cmsg_type) {
547 case SCM_TIMESTAMPNS:
548 recv_time = (struct timespec *) CMSG_DATA(cmsg);
553 log_error("Invalid packet timestamp.");
558 log_debug("Unexpected reply. Ignoring.");
562 m->missed_replies = 0;
564 /* check our "time cookie" (we just stored nanoseconds in the fraction field) */
565 if (be32toh(ntpmsg.origin_time.sec) != m->trans_time.tv_sec + OFFSET_1900_1970 ||
566 be32toh(ntpmsg.origin_time.frac) != m->trans_time.tv_nsec) {
567 log_debug("Invalid reply; not our transmit time. Ignoring.");
571 m->event_timeout = sd_event_source_unref(m->event_timeout);
573 if (be32toh(ntpmsg.recv_time.sec) < TIME_EPOCH + OFFSET_1900_1970 ||
574 be32toh(ntpmsg.trans_time.sec) < TIME_EPOCH + OFFSET_1900_1970) {
575 log_debug("Invalid reply, returned times before epoch. Ignoring.");
576 return manager_connect(m);
579 if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC ||
580 ntpmsg.stratum == 0 || ntpmsg.stratum >= 16) {
581 log_debug("Server is not synchronized. Disconnecting.");
582 return manager_connect(m);
585 if (!IN_SET(NTP_FIELD_VERSION(ntpmsg.field), 3, 4)) {
586 log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
587 return manager_connect(m);
590 if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
591 log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
592 return manager_connect(m);
595 root_distance = ntp_ts_short_to_d(&ntpmsg.root_delay) / 2 + ntp_ts_short_to_d(&ntpmsg.root_dispersion);
596 if (root_distance > NTP_MAX_ROOT_DISTANCE) {
597 log_debug("Server has too large root distance. Disconnecting.");
598 return manager_connect(m);
603 m->retry_interval = 0;
606 manager_listen_stop(m);
608 /* announce leap seconds */
609 if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
611 else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
617 * "Timestamp Name ID When Generated
618 * ------------------------------------------------------------
619 * Originate Timestamp T1 time request sent by client
620 * Receive Timestamp T2 time request received by server
621 * Transmit Timestamp T3 time reply sent by server
622 * Destination Timestamp T4 time reply received by client
624 * The round-trip delay, d, and system clock offset, t, are defined as:
625 * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
627 origin = ts_to_d(&m->trans_time) + OFFSET_1900_1970;
628 receive = ntp_ts_to_d(&ntpmsg.recv_time);
629 trans = ntp_ts_to_d(&ntpmsg.trans_time);
630 dest = ts_to_d(recv_time) + OFFSET_1900_1970;
632 offset = ((receive - origin) + (trans - dest)) / 2;
633 delay = (dest - origin) - (trans - receive);
635 spike = manager_sample_spike_detection(m, offset, delay);
637 manager_adjust_poll(m, offset, spike);
639 log_debug("NTP response:\n"
644 " precision : %.6f sec (%d)\n"
645 " root distance: %.6f sec\n"
646 " reference : %.4s\n"
651 " offset : %+.3f sec\n"
652 " delay : %+.3f sec\n"
653 " packet count : %"PRIu64"\n"
655 " poll interval: " USEC_FMT "\n",
656 NTP_FIELD_LEAP(ntpmsg.field),
657 NTP_FIELD_VERSION(ntpmsg.field),
658 NTP_FIELD_MODE(ntpmsg.field),
660 exp2(ntpmsg.precision), ntpmsg.precision,
662 ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
663 origin - OFFSET_1900_1970,
664 receive - OFFSET_1900_1970,
665 trans - OFFSET_1900_1970,
666 dest - OFFSET_1900_1970,
669 m->samples_jitter, spike ? " spike" : "",
670 m->poll_interval_usec / USEC_PER_SEC);
674 r = manager_adjust_clock(m, offset, leap_sec);
676 log_error_errno(errno, "Failed to call clock_adjtime(): %m");
679 log_info("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+ippm%s",
680 m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_ppm,
681 spike ? " (ignored)" : "");
683 r = manager_arm_timer(m, m->poll_interval_usec);
685 return log_error_errno(r, "Failed to rearm timer: %m");
690 static int manager_listen_setup(Manager *m) {
691 union sockaddr_union addr = {};
692 static const int tos = IPTOS_LOWDELAY;
693 static const int on = 1;
698 if (m->server_socket >= 0)
701 assert(!m->event_receive);
702 assert(m->current_server_address);
704 addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
706 m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
707 if (m->server_socket < 0)
710 r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
714 r = setsockopt(m->server_socket, SOL_SOCKET, SO_TIMESTAMPNS, &on, sizeof(on));
718 (void) setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
720 return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
723 static void manager_listen_stop(Manager *m) {
726 m->event_receive = sd_event_source_unref(m->event_receive);
727 m->server_socket = safe_close(m->server_socket);
730 static int manager_begin(Manager *m) {
731 _cleanup_free_ char *pretty = NULL;
735 assert_return(m->current_server_name, -EHOSTUNREACH);
736 assert_return(m->current_server_address, -EHOSTUNREACH);
738 m->missed_replies = NTP_MAX_MISSED_REPLIES;
739 if (m->poll_interval_usec == 0)
740 m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
742 server_address_pretty(m->current_server_address, &pretty);
743 log_info("Using NTP server %s (%s).", strna(pretty), m->current_server_name->string);
744 sd_notifyf(false, "STATUS=Using Time Server %s (%s).", strna(pretty), m->current_server_name->string);
746 r = manager_clock_watch_setup(m);
750 return manager_send_request(m);
753 void manager_set_server_name(Manager *m, ServerName *n) {
756 if (m->current_server_name == n)
759 m->current_server_name = n;
760 m->current_server_address = NULL;
762 manager_disconnect(m);
765 log_debug("Selected server %s.", n->string);
768 void manager_set_server_address(Manager *m, ServerAddress *a) {
771 if (m->current_server_address == a)
774 m->current_server_address = a;
775 /* If a is NULL, we are just clearing the address, without
776 * changing the name. Keep the existing name in that case. */
778 m->current_server_name = a->name;
780 manager_disconnect(m);
783 _cleanup_free_ char *pretty = NULL;
784 server_address_pretty(a, &pretty);
785 log_debug("Selected address %s of server %s.", strna(pretty), a->name->string);
789 static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) {
790 Manager *m = userdata;
795 assert(m->current_server_name);
797 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
800 log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
803 return manager_connect(m);
806 for (; ai; ai = ai->ai_next) {
807 _cleanup_free_ char *pretty = NULL;
811 assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
813 if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
814 log_warning("Unsuitable address protocol for %s", m->current_server_name->string);
818 r = server_address_new(m->current_server_name, &a, (const union sockaddr_union*) ai->ai_addr, ai->ai_addrlen);
820 return log_error_errno(r, "Failed to add server address: %m");
822 server_address_pretty(a, &pretty);
823 log_debug("Resolved address %s for %s.", pretty, m->current_server_name->string);
826 if (!m->current_server_name->addresses) {
827 log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
830 return manager_connect(m);
833 manager_set_server_address(m, m->current_server_name->addresses);
835 return manager_begin(m);
838 static int manager_retry_connect(sd_event_source *source, usec_t usec, void *userdata) {
839 Manager *m = userdata;
843 return manager_connect(m);
846 int manager_connect(Manager *m) {
851 manager_disconnect(m);
853 m->event_retry = sd_event_source_unref(m->event_retry);
854 if (!ratelimit_test(&m->ratelimit)) {
855 log_debug("Slowing down attempts to contact servers.");
857 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);
859 return log_error_errno(r, "Failed to create retry timer: %m");
864 /* If we already are operating on some address, switch to the
866 if (m->current_server_address && m->current_server_address->addresses_next)
867 manager_set_server_address(m, m->current_server_address->addresses_next);
869 struct addrinfo hints = {
870 .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
871 .ai_socktype = SOCK_DGRAM,
874 /* Hmm, we are through all addresses, let's look for the next host instead */
875 if (m->current_server_name && m->current_server_name->names_next)
876 manager_set_server_name(m, m->current_server_name->names_next);
881 /* Our current server name list is exhausted,
882 * let's find the next one to iterate. First
883 * we try the system list, then the link list.
884 * After having processed the link list we
885 * jump back to the system list. However, if
886 * both lists are empty, we change to the
888 if (!m->current_server_name || m->current_server_name->type == SERVER_LINK) {
889 f = m->system_servers;
895 f = m->system_servers;
901 f = m->fallback_servers;
904 manager_set_server_name(m, NULL);
905 log_debug("No server found.");
909 if (restart && !m->exhausted_servers && m->poll_interval_usec) {
910 log_debug("Waiting after exhausting servers.");
911 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);
913 return log_error_errno(r, "Failed to create retry timer: %m");
915 m->exhausted_servers = true;
917 /* Increase the polling interval */
918 if (m->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
919 m->poll_interval_usec *= 2;
924 m->exhausted_servers = false;
926 manager_set_server_name(m, f);
929 /* Tell the resolver to reread /etc/resolv.conf, in
930 * case it changed. */
933 /* Flush out any previously resolved addresses */
934 server_name_flush_addresses(m->current_server_name);
936 log_debug("Resolving %s...", m->current_server_name->string);
938 r = sd_resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, m);
940 return log_error_errno(r, "Failed to create resolver: %m");
945 r = manager_begin(m);
952 void manager_disconnect(Manager *m) {
955 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
957 m->event_timer = sd_event_source_unref(m->event_timer);
959 manager_listen_stop(m);
961 m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
962 m->clock_watch_fd = safe_close(m->clock_watch_fd);
964 m->event_timeout = sd_event_source_unref(m->event_timeout);
966 sd_notifyf(false, "STATUS=Idle.");
969 void manager_flush_server_names(Manager *m, ServerType t) {
972 if (t == SERVER_SYSTEM)
973 while (m->system_servers)
974 server_name_free(m->system_servers);
976 if (t == SERVER_LINK)
977 while (m->link_servers)
978 server_name_free(m->link_servers);
980 if (t == SERVER_FALLBACK)
981 while (m->fallback_servers)
982 server_name_free(m->fallback_servers);
985 void manager_free(Manager *m) {
989 manager_disconnect(m);
990 manager_flush_server_names(m, SERVER_SYSTEM);
991 manager_flush_server_names(m, SERVER_LINK);
992 manager_flush_server_names(m, SERVER_FALLBACK);
994 sd_event_source_unref(m->event_retry);
996 sd_event_source_unref(m->network_event_source);
997 sd_network_monitor_unref(m->network_monitor);
999 sd_resolve_unref(m->resolve);
1000 sd_event_unref(m->event);
1005 static int manager_network_read_link_servers(Manager *m) {
1006 _cleanup_strv_free_ char **ntp = NULL;
1013 r = sd_network_get_ntp(&ntp);
1017 LIST_FOREACH(names, n, m->link_servers)
1020 STRV_FOREACH(i, ntp) {
1023 LIST_FOREACH(names, n, m->link_servers)
1024 if (streq(n->string, *i)) {
1031 r = server_name_new(m, NULL, SERVER_LINK, *i);
1037 LIST_FOREACH_SAFE(names, n, nx, m->link_servers)
1039 server_name_free(n);
1044 manager_flush_server_names(m, SERVER_LINK);
1048 static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
1049 Manager *m = userdata;
1050 bool connected, online;
1055 sd_network_monitor_flush(m->network_monitor);
1057 manager_network_read_link_servers(m);
1059 /* check if the machine is online */
1060 online = network_is_online();
1062 /* check if the client is currently connected */
1063 connected = m->server_socket >= 0 || m->resolve_query || m->exhausted_servers;
1065 if (connected && !online) {
1066 log_info("No network connectivity, watching for changes.");
1067 manager_disconnect(m);
1069 } else if (!connected && online) {
1070 log_info("Network configuration changed, trying to establish connection.");
1072 if (m->current_server_address)
1073 r = manager_begin(m);
1075 r = manager_connect(m);
1083 static int manager_network_monitor_listen(Manager *m) {
1088 r = sd_network_monitor_new(&m->network_monitor, NULL);
1092 fd = sd_network_monitor_get_fd(m->network_monitor);
1096 events = sd_network_monitor_get_events(m->network_monitor);
1100 r = sd_event_add_io(m->event, &m->network_event_source, fd, events, manager_network_event_handler, m);
1107 int manager_new(Manager **ret) {
1108 _cleanup_(manager_freep) Manager *m = NULL;
1113 m = new0(Manager, 1);
1117 m->server_socket = m->clock_watch_fd = -1;
1119 RATELIMIT_INIT(m->ratelimit, RATELIMIT_INTERVAL_USEC, RATELIMIT_BURST);
1121 r = manager_parse_server_string(m, SERVER_FALLBACK, NTP_SERVERS);
1125 r = sd_event_default(&m->event);
1129 sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
1130 sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
1132 sd_event_set_watchdog(m->event, true);
1134 r = sd_resolve_default(&m->resolve);
1138 r = sd_resolve_attach_event(m->resolve, m->event, 0);
1142 r = manager_network_monitor_listen(m);
1146 manager_network_read_link_servers(m);