1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2014 Kay Sievers
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>
38 #include "sparse-endian.h"
40 #include "socket-util.h"
42 #include "ratelimit.h"
44 #include "sd-resolve.h"
45 #include "sd-daemon.h"
47 #define TIME_T_MAX (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
50 #define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
53 /* expected accuracy of time synchronization; used to adjust the poll interval */
54 #define NTP_ACCURACY_SEC 0.2
57 * "A client MUST NOT under any conditions use a poll interval less
60 #define NTP_POLL_INTERVAL_MIN_SEC 32
61 #define NTP_POLL_INTERVAL_MAX_SEC 2048
64 * Maximum delta in seconds which the system clock is gradually adjusted
65 * (slew) to approach the network time. Deltas larger that this are set by
66 * letting the system time jump. The kernel's limit for adjtime is 0.5s.
68 #define NTP_MAX_ADJUST 0.4
70 /* NTP protocol, packet header */
71 #define NTP_LEAP_PLUSSEC 1
72 #define NTP_LEAP_MINUSSEC 2
73 #define NTP_LEAP_NOTINSYNC 3
74 #define NTP_MODE_CLIENT 3
75 #define NTP_MODE_SERVER 4
76 #define NTP_FIELD_LEAP(f) (((f) >> 6) & 3)
77 #define NTP_FIELD_VERSION(f) (((f) >> 3) & 7)
78 #define NTP_FIELD_MODE(f) ((f) & 7)
79 #define NTP_FIELD(l, v, m) (((l) << 6) | ((v) << 3) | (m))
82 * "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
83 * in seconds relative to 0h on 1 January 1900."
85 #define OFFSET_1900_1970 2208988800UL
87 #define RETRY_USEC (30*USEC_PER_SEC)
88 #define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
89 #define RATELIMIT_BURST 5
106 struct ntp_ts_short root_delay;
107 struct ntp_ts_short root_dispersion;
109 struct ntp_ts reference_time;
110 struct ntp_ts origin_time;
111 struct ntp_ts recv_time;
112 struct ntp_ts trans_time;
115 typedef struct Manager Manager;
116 typedef struct ServerAddress ServerAddress;
117 typedef struct ServerName ServerName;
119 struct ServerAddress {
120 union sockaddr_union sockaddr;
122 LIST_FIELDS(ServerAddress, addresses);
127 LIST_HEAD(ServerAddress, addresses);
128 LIST_FIELDS(ServerName, names);
135 LIST_HEAD(ServerName, servers);
140 sd_resolve_query *resolve_query;
141 sd_event_source *event_receive;
142 ServerName *current_server_name;
143 ServerAddress *current_server_address;
145 uint64_t packet_count;
147 /* last sent packet */
148 struct timespec trans_time_mon;
149 struct timespec trans_time;
150 usec_t retry_interval;
154 sd_event_source *event_timer;
155 usec_t poll_interval_usec;
163 unsigned int samples_idx;
164 double samples_jitter;
170 /* watch for time changes */
171 sd_event_source *event_clock_watch;
174 /* Retry connections */
175 sd_event_source *event_retry;
177 /* Handle SIGINT/SIGTERM */
178 sd_event_source *sigterm, *sigint;
181 static void manager_free(Manager *m);
182 DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free);
183 #define _cleanup_manager_free_ _cleanup_(manager_freep)
185 static int manager_arm_timer(Manager *m, usec_t next);
186 static int manager_clock_watch_setup(Manager *m);
187 static int manager_connect(Manager *m);
188 static void manager_disconnect(Manager *m);
190 static double ntp_ts_to_d(const struct ntp_ts *ts) {
191 return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
194 static double ts_to_d(const struct timespec *ts) {
195 return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
198 static double tv_to_d(const struct timeval *tv) {
199 return tv->tv_sec + (1.0e-6 * tv->tv_usec);
202 static double square(double d) {
206 static int manager_send_request(Manager *m) {
207 _cleanup_free_ char *pretty = NULL;
208 struct ntp_msg ntpmsg = {
210 * "The client initializes the NTP message header, sends the request
211 * to the server, and strips the time of day from the Transmit
212 * Timestamp field of the reply. For this purpose, all the NTP
213 * header fields are set to 0, except the Mode, VN, and optional
214 * Transmit Timestamp fields."
216 .field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
222 assert(m->current_server_name);
223 assert(m->current_server_address);
226 * Set transmit timestamp, remember it; the server will send that back
227 * as the origin timestamp and we have an indication that this is the
228 * matching answer to our request.
230 * The actual value does not matter, We do not care about the correct
231 * NTP UINT_MAX fraction; we just pass the plain nanosecond value.
233 assert_se(clock_gettime(CLOCK_MONOTONIC, &m->trans_time_mon) >= 0);
234 assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
235 ntpmsg.trans_time.sec = htobe32(m->trans_time.tv_sec + OFFSET_1900_1970);
236 ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
238 r = sockaddr_pretty(&m->current_server_address->sockaddr.sa, m->current_server_address->socklen, true, &pretty);
240 log_error("Failed to format sockaddr: %s", strerror(-r));
244 len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
245 if (len == sizeof(ntpmsg)) {
247 log_debug("Sent NTP request to %s (%s)", pretty, m->current_server_name->string);
249 log_debug("Sending NTP request to %s (%s) failed: %m", pretty, m->current_server_name->string);
251 /* re-arm timer with incresing timeout, in case the packets never arrive back */
252 if (m->retry_interval > 0) {
253 if (m->retry_interval < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
254 m->retry_interval *= 2;
256 m->retry_interval = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
258 r = manager_arm_timer(m, m->retry_interval);
260 log_error("Failed to rearm timer: %s", strerror(-r));
267 static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
268 Manager *m = userdata;
272 return manager_send_request(m);
275 static int manager_arm_timer(Manager *m, usec_t next) {
279 assert(m->event_receive);
282 m->event_timer = sd_event_source_unref(m->event_timer);
286 if (m->event_timer) {
287 r = sd_event_source_set_time(m->event_timer, now(CLOCK_MONOTONIC) + next);
291 return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
294 return sd_event_add_time(
298 now(CLOCK_MONOTONIC) + next, 0,
302 static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
303 Manager *m = userdata;
308 manager_clock_watch_setup(m);
310 /* skip our own jumps */
317 log_info("System time changed. Resyncing.");
318 m->poll_resync = true;
319 return manager_send_request(m);
322 /* wake up when the system time changes underneath us */
323 static int manager_clock_watch_setup(Manager *m) {
325 struct itimerspec its = {
326 .it_value.tv_sec = TIME_T_MAX
333 m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
334 m->clock_watch_fd = safe_close(m->clock_watch_fd);
336 m->clock_watch_fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
337 if (m->clock_watch_fd < 0) {
338 log_error("Failed to create timerfd: %m");
342 if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0) {
343 log_error("Failed to set up timerfd: %m");
347 r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, manager_clock_watch, m);
349 log_error("Failed to create clock watch event source: %s", strerror(-r));
356 static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
357 struct timex tmx = {};
363 * For small deltas, tell the kernel to gradually adjust the system
364 * clock to the NTP time, larger deltas are just directly set.
366 * Clear STA_UNSYNC, it will enable the kernel's 11-minute mode, which
367 * syncs the system time periodically to the hardware clock.
369 if (fabs(offset) < NTP_MAX_ADJUST) {
370 tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR;
371 tmx.status = STA_PLL;
372 tmx.offset = offset * NSEC_PER_SEC;
373 tmx.constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4;
376 log_debug(" adjust (slew): %+.3f sec\n", offset);
378 tmx.modes = ADJ_SETOFFSET | ADJ_NANO;
380 /* ADJ_NANO uses nanoseconds in the microseconds field */
381 tmx.time.tv_sec = (long)offset;
382 tmx.time.tv_usec = (offset - tmx.time.tv_sec) * NSEC_PER_SEC;
384 /* the kernel expects -0.3s as {-1, 7000.000.000} */
385 if (tmx.time.tv_usec < 0) {
386 tmx.time.tv_sec -= 1;
387 tmx.time.tv_usec += NSEC_PER_SEC;
391 log_debug(" adjust (jump): %+.3f sec\n", offset);
396 tmx.status |= STA_INS;
399 tmx.status |= STA_DEL;
403 r = clock_adjtime(CLOCK_REALTIME, &tmx);
407 m->drift_ppm = tmx.freq / 65536;
409 log_debug(" status : %04i %s\n"
410 " time now : %li.%03lli\n"
412 " offset : %+.3f sec\n"
413 " freq offset : %+li (%i ppm)\n",
414 tmx.status, tmx.status & STA_UNSYNC ? "" : "sync",
415 tmx.time.tv_sec, tmx.time.tv_usec / NSEC_PER_MSEC,
417 (double)tmx.offset / NSEC_PER_SEC,
418 tmx.freq, m->drift_ppm);
423 static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
424 unsigned int i, idx_cur, idx_new, idx_min;
432 /* ignore initial sample */
433 if (m->packet_count == 1)
436 /* store the current data in our samples array */
437 idx_cur = m->samples_idx;
438 idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
439 m->samples_idx = idx_new;
440 m->samples[idx_new].offset = offset;
441 m->samples[idx_new].delay = delay;
443 /* calculate new jitter value from the RMS differences relative to the lowest delay sample */
444 jitter = m->samples_jitter;
445 for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
446 if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
450 for (i = 0; i < ELEMENTSOF(m->samples); i++)
451 j += square(m->samples[i].offset - m->samples[idx_min].offset);
452 m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
454 /* ignore samples when resyncing */
458 /* always accept offset if we are farther off than the round-trip delay */
459 if (fabs(offset) > delay)
462 /* we need a few samples before looking at them */
463 if (m->packet_count < 4)
466 /* do not accept anything worse than the maximum possible error of the best sample */
467 if (fabs(offset) > m->samples[idx_min].delay)
470 /* compare the difference between the current offset to the previous offset and jitter */
471 return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
474 static void manager_adjust_poll(Manager *m, double offset, bool spike) {
477 if (m->poll_resync) {
478 m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
479 m->poll_resync = false;
483 /* set to minimal poll interval */
484 if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
485 m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
489 /* increase polling interval */
490 if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
491 if (m->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
492 m->poll_interval_usec *= 2;
496 /* decrease polling interval */
497 if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
498 if (m->poll_interval_usec > NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC)
499 m->poll_interval_usec /= 2;
504 static bool sockaddr_equal(union sockaddr_union *a, union sockaddr_union *b) {
508 if (a->sa.sa_family != b->sa.sa_family)
511 if (a->sa.sa_family == AF_INET)
512 return a->in.sin_addr.s_addr == b->in.sin_addr.s_addr;
514 if (a->sa.sa_family == AF_INET6)
515 return memcmp(&a->in6.sin6_addr, &b->in6.sin6_addr, sizeof(a->in6.sin6_addr)) == 0;
520 static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
521 _cleanup_free_ char *pretty = NULL;
522 Manager *m = userdata;
523 struct ntp_msg ntpmsg;
527 .iov_len = sizeof(ntpmsg),
530 struct cmsghdr cmsghdr;
531 uint8_t buf[CMSG_SPACE(sizeof(struct timeval))];
533 union sockaddr_union server_addr;
534 struct msghdr msghdr = {
537 .msg_control = &control,
538 .msg_controllen = sizeof(control),
539 .msg_name = &server_addr,
540 .msg_namelen = sizeof(server_addr),
542 struct cmsghdr *cmsg;
543 struct timespec now_ts;
544 struct timeval *recv_time;
546 double origin, receive, trans, dest;
547 double delay, offset;
555 if (revents & (EPOLLHUP|EPOLLERR)) {
556 log_warning("Server connection returned error.");
557 return manager_connect(m);
560 len = recvmsg(fd, &msghdr, MSG_DONTWAIT);
565 log_warning("Error receiving message. Disconnecting.");
566 return manager_connect(m);
569 if (iov.iov_len < sizeof(struct ntp_msg)) {
570 log_warning("Invalid response from server. Disconnecting.");
571 return manager_connect(m);
574 if (!m->current_server_name ||
575 !m->current_server_address ||
576 !sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
577 log_debug("Response from unknown server.");
582 for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {
583 if (cmsg->cmsg_level != SOL_SOCKET)
586 switch (cmsg->cmsg_type) {
588 recv_time = (struct timeval *) CMSG_DATA(cmsg);
593 log_error("Invalid packet timestamp.");
598 log_debug("Unexpected reply. Ignoring.");
602 /* check our "time cookie" (we just stored nanoseconds in the fraction field) */
603 if (be32toh(ntpmsg.origin_time.sec) != m->trans_time.tv_sec + OFFSET_1900_1970 ||
604 be32toh(ntpmsg.origin_time.frac) != m->trans_time.tv_nsec) {
605 log_debug("Invalid reply; not our transmit time. Ignoring.");
609 if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC) {
610 log_debug("Server is not synchronized. Disconnecting.");
611 return manager_connect(m);
614 if (NTP_FIELD_VERSION(ntpmsg.field) != 4) {
615 log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
616 return manager_connect(m);
619 if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
620 log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
621 return manager_connect(m);
626 m->retry_interval = 0;
628 /* announce leap seconds */
629 if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
631 else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
637 * "Timestamp Name ID When Generated
638 * ------------------------------------------------------------
639 * Originate Timestamp T1 time request sent by client
640 * Receive Timestamp T2 time request received by server
641 * Transmit Timestamp T3 time reply sent by server
642 * Destination Timestamp T4 time reply received by client
644 * The round-trip delay, d, and system clock offset, t, are defined as:
645 * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
647 assert_se(clock_gettime(CLOCK_MONOTONIC, &now_ts) >= 0);
648 origin = tv_to_d(recv_time) - (ts_to_d(&now_ts) - ts_to_d(&m->trans_time_mon)) + OFFSET_1900_1970;
649 receive = ntp_ts_to_d(&ntpmsg.recv_time);
650 trans = ntp_ts_to_d(&ntpmsg.trans_time);
651 dest = tv_to_d(recv_time) + OFFSET_1900_1970;
653 offset = ((receive - origin) + (trans - dest)) / 2;
654 delay = (dest - origin) - (trans - receive);
656 spike = manager_sample_spike_detection(m, offset, delay);
658 manager_adjust_poll(m, offset, spike);
660 log_debug("NTP response:\n"
665 " precision : %.6f sec (%d)\n"
666 " reference : %.4s\n"
671 " offset : %+.3f sec\n"
672 " delay : %+.3f sec\n"
673 " packet count : %"PRIu64"\n"
675 " poll interval: %llu\n",
676 NTP_FIELD_LEAP(ntpmsg.field),
677 NTP_FIELD_VERSION(ntpmsg.field),
678 NTP_FIELD_MODE(ntpmsg.field),
680 exp2(ntpmsg.precision), ntpmsg.precision,
681 ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
682 origin - OFFSET_1900_1970,
683 receive - OFFSET_1900_1970,
684 trans - OFFSET_1900_1970,
685 dest - OFFSET_1900_1970,
688 m->samples_jitter, spike ? " spike" : "",
689 m->poll_interval_usec / USEC_PER_SEC);
692 r = manager_adjust_clock(m, offset, leap_sec);
694 log_error("Failed to call clock_adjtime(): %m");
697 r = sockaddr_pretty(&m->current_server_address->sockaddr.sa, m->current_server_address->socklen, true, &pretty);
699 log_error("Failed to format socket address: %s", strerror(-r));
703 log_info("%s (%s): interval/delta/delay/jitter/drift %llus/%+.3fs/%.3fs/%.3fs/%+ippm%s",
704 pretty, m->current_server_name->string, m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_ppm,
705 spike ? " (ignored)" : "");
707 r = manager_arm_timer(m, m->poll_interval_usec);
709 log_error("Failed to rearm timer: %s", strerror(-r));
716 static int manager_listen_setup(Manager *m) {
717 union sockaddr_union addr = {};
718 static const int tos = IPTOS_LOWDELAY;
719 static const int on = 1;
724 assert(m->server_socket < 0);
725 assert(!m->event_receive);
726 assert(m->current_server_address);
728 addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
730 m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
731 if (m->server_socket < 0)
734 r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
738 r = setsockopt(m->server_socket, SOL_SOCKET, SO_TIMESTAMP, &on, sizeof(on));
742 setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
744 return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
747 static int manager_begin(Manager *m) {
748 _cleanup_free_ char *pretty = NULL;
752 assert_return(m->current_server_name, -EHOSTUNREACH);
753 assert_return(m->current_server_address, -EHOSTUNREACH);
755 m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
757 r = sockaddr_pretty(&m->current_server_address->sockaddr.sa, m->current_server_address->socklen, true, &pretty);
759 log_warning("Failed to decode address of %s: %s", m->current_server_name->string, strerror(-r));
763 log_debug("Connecting to NTP server %s (%s).", pretty, m->current_server_name->string);
764 sd_notifyf(false, "STATUS=Using Time Server %s (%s)", pretty, m->current_server_name->string);
766 r = manager_listen_setup(m);
768 log_warning("Failed to setup connection socket: %s", strerror(-r));
772 r = manager_clock_watch_setup(m);
776 return manager_send_request(m);
779 static void server_name_flush_addresses(ServerName *n) {
784 while ((a = n->addresses)) {
785 LIST_REMOVE(addresses, n->addresses, a);
790 static void manager_flush_names(Manager *m) {
795 while ((n = m->servers)) {
796 LIST_REMOVE(names, m->servers, n);
798 server_name_flush_addresses(n);
803 static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) {
804 Manager *m = userdata;
805 ServerAddress *a, *last = NULL;
809 assert(m->current_server_name);
811 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
814 log_error("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
817 return manager_connect(m);
820 server_name_flush_addresses(m->current_server_name);
822 for (; ai; ai = ai->ai_next) {
823 _cleanup_free_ char *pretty = NULL;
826 assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
827 assert(ai->ai_addrlen <= sizeof(union sockaddr_union));
829 if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
830 log_warning("Unsuitable address protocol for %s", m->current_server_name->string);
834 a = new0(ServerAddress, 1);
838 memcpy(&a->sockaddr, ai->ai_addr, ai->ai_addrlen);
839 a->socklen = ai->ai_addrlen;
841 LIST_INSERT_AFTER(addresses, m->current_server_name->addresses, last, a);
844 sockaddr_pretty(&a->sockaddr.sa, a->socklen, true, &pretty);
845 log_debug("Found address %s for %s.", pretty, m->current_server_name->string);
848 if (!m->current_server_name->addresses) {
849 log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
852 return manager_connect(m);
855 m->current_server_address = m->current_server_name->addresses;
857 return manager_begin(m);
860 static int manager_retry(sd_event_source *source, usec_t usec, void *userdata) {
861 Manager *m = userdata;
865 return manager_connect(m);
868 static int manager_connect(Manager *m) {
870 struct addrinfo hints = {
871 .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
872 .ai_socktype = SOCK_DGRAM,
878 manager_disconnect(m);
880 m->event_retry = sd_event_source_unref(m->event_retry);
881 if (!ratelimit_test(&m->ratelimit)) {
882 log_debug("Slowing down attempts to contact servers.");
884 r = sd_event_add_time(m->event, &m->event_retry, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + RETRY_USEC, 0, manager_retry, m);
886 log_error("Failed to create retry timer: %s", strerror(-r));
893 /* If we already are operating on some address, switch to the
895 if (m->current_server_address && m->current_server_address->addresses_next)
896 m->current_server_address = m->current_server_address->addresses_next;
898 /* Hmm, we are through all addresses, let's look for the next host instead */
899 m->current_server_address = NULL;
901 if (m->current_server_name && m->current_server_name->names_next)
902 m->current_server_name = m->current_server_name->names_next;
905 m->current_server_name = NULL;
906 log_debug("No server found.");
910 m->current_server_name = m->servers;
913 r = sd_resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, m);
915 log_error("Failed to create resolver: %s", strerror(-r));
922 r = manager_begin(m);
929 static int manager_add_server(Manager *m, const char *server) {
935 n = new0(ServerName, 1);
939 n->string = strdup(server);
945 LIST_PREPEND(names, m->servers, n);
949 static void manager_disconnect(Manager *m) {
952 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
954 m->event_timer = sd_event_source_unref(m->event_timer);
956 m->event_receive = sd_event_source_unref(m->event_receive);
957 m->server_socket = safe_close(m->server_socket);
959 m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
960 m->clock_watch_fd = safe_close(m->clock_watch_fd);
963 static int manager_new(Manager **ret) {
964 _cleanup_manager_free_ Manager *m = NULL;
967 m = new0(Manager, 1);
971 m->server_socket = m->clock_watch_fd = -1;
973 RATELIMIT_INIT(m->ratelimit, RATELIMIT_INTERVAL_USEC, RATELIMIT_BURST);
975 r = sd_event_default(&m->event);
979 sd_event_add_signal(m->event, &m->sigterm, SIGTERM, NULL, NULL);
980 sd_event_add_signal(m->event, &m->sigint, SIGINT, NULL, NULL);
982 r = sd_resolve_default(&m->resolve);
986 r = sd_resolve_attach_event(m->resolve, m->event, 0);
990 r = manager_clock_watch_setup(m);
1000 static void manager_free(Manager *m) {
1004 manager_disconnect(m);
1005 manager_flush_names(m);
1007 sd_event_source_unref(m->sigint);
1008 sd_event_source_unref(m->sigterm);
1010 sd_event_source_unref(m->event_retry);
1012 sd_resolve_unref(m->resolve);
1013 sd_event_unref(m->event);
1018 int main(int argc, char *argv[]) {
1019 _cleanup_manager_free_ Manager *m = NULL;
1022 log_set_target(LOG_TARGET_AUTO);
1023 log_parse_environment();
1026 assert_se(sigprocmask_many(SIG_BLOCK, SIGTERM, SIGINT, -1) == 0);
1028 r = manager_new(&m);
1030 log_error("Failed to allocate manager: %s", strerror(-r));
1034 sd_notify(false, "READY=1");
1036 r = manager_add_server(m, "time1.google.com");
1038 log_error("Failed to add server: %s", strerror(-r));
1042 r = manager_connect(m);
1046 r = sd_event_loop(m->event);
1048 log_error("Failed to run event loop: %s", strerror(-r));
1052 sd_event_get_exit_code(m->event, &r);
1055 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;