2 This file is part of systemd.
4 Copyright 2014 Kay Sievers, Lennart Poettering
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include <netinet/in.h>
23 #include <netinet/ip.h>
26 #include <sys/socket.h>
27 #include <sys/timerfd.h>
28 #include <sys/timex.h>
29 #include <sys/types.h>
32 #include "sd-daemon.h"
34 #include "alloc-util.h"
40 #include "network-util.h"
41 #include "ratelimit.h"
42 #include "socket-util.h"
43 #include "sparse-endian.h"
44 #include "string-util.h"
46 #include "time-util.h"
47 #include "timesyncd-conf.h"
48 #include "timesyncd-manager.h"
52 #define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
55 /* expected accuracy of time synchronization; used to adjust the poll interval */
56 #define NTP_ACCURACY_SEC 0.2
59 * "A client MUST NOT under any conditions use a poll interval less
62 #define NTP_POLL_INTERVAL_MIN_SEC 32
63 #define NTP_POLL_INTERVAL_MAX_SEC 2048
66 * Maximum delta in seconds which the system clock is gradually adjusted
67 * (slew) to approach the network time. Deltas larger that this are set by
68 * letting the system time jump. The kernel's limit for adjtime is 0.5s.
70 #define NTP_MAX_ADJUST 0.4
72 /* NTP protocol, packet header */
73 #define NTP_LEAP_PLUSSEC 1
74 #define NTP_LEAP_MINUSSEC 2
75 #define NTP_LEAP_NOTINSYNC 3
76 #define NTP_MODE_CLIENT 3
77 #define NTP_MODE_SERVER 4
78 #define NTP_FIELD_LEAP(f) (((f) >> 6) & 3)
79 #define NTP_FIELD_VERSION(f) (((f) >> 3) & 7)
80 #define NTP_FIELD_MODE(f) ((f) & 7)
81 #define NTP_FIELD(l, v, m) (((l) << 6) | ((v) << 3) | (m))
83 /* Maximum acceptable root distance in seconds. */
84 #define NTP_MAX_ROOT_DISTANCE 5.0
86 /* Maximum number of missed replies before selecting another source. */
87 #define NTP_MAX_MISSED_REPLIES 2
90 * "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
91 * in seconds relative to 0h on 1 January 1900."
93 #define OFFSET_1900_1970 UINT64_C(2208988800)
95 #define RETRY_USEC (30*USEC_PER_SEC)
96 #define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
97 #define RATELIMIT_BURST 10
99 #define TIMEOUT_USEC (10*USEC_PER_SEC)
106 struct ntp_ts_short
{
116 struct ntp_ts_short root_delay
;
117 struct ntp_ts_short root_dispersion
;
119 struct ntp_ts reference_time
;
120 struct ntp_ts origin_time
;
121 struct ntp_ts recv_time
;
122 struct ntp_ts trans_time
;
125 static int manager_arm_timer(Manager
*m
, usec_t next
);
126 static int manager_clock_watch_setup(Manager
*m
);
127 static int manager_listen_setup(Manager
*m
);
128 static void manager_listen_stop(Manager
*m
);
130 static double ntp_ts_short_to_d(const struct ntp_ts_short
*ts
) {
131 return be16toh(ts
->sec
) + (be16toh(ts
->frac
) / 65536.0);
134 static double ntp_ts_to_d(const struct ntp_ts
*ts
) {
135 return be32toh(ts
->sec
) + ((double)be32toh(ts
->frac
) / UINT_MAX
);
138 static double ts_to_d(const struct timespec
*ts
) {
139 return ts
->tv_sec
+ (1.0e-9 * ts
->tv_nsec
);
142 static int manager_timeout(sd_event_source
*source
, usec_t usec
, void *userdata
) {
143 _cleanup_free_
char *pretty
= NULL
;
144 Manager
*m
= userdata
;
147 assert(m
->current_server_name
);
148 assert(m
->current_server_address
);
150 server_address_pretty(m
->current_server_address
, &pretty
);
151 log_info("Timed out waiting for reply from %s (%s).", strna(pretty
), m
->current_server_name
->string
);
153 return manager_connect(m
);
156 static int manager_send_request(Manager
*m
) {
157 _cleanup_free_
char *pretty
= NULL
;
158 struct ntp_msg ntpmsg
= {
160 * "The client initializes the NTP message header, sends the request
161 * to the server, and strips the time of day from the Transmit
162 * Timestamp field of the reply. For this purpose, all the NTP
163 * header fields are set to 0, except the Mode, VN, and optional
164 * Transmit Timestamp fields."
166 .field
= NTP_FIELD(0, 4, NTP_MODE_CLIENT
),
172 assert(m
->current_server_name
);
173 assert(m
->current_server_address
);
175 m
->event_timeout
= sd_event_source_unref(m
->event_timeout
);
177 r
= manager_listen_setup(m
);
179 return log_warning_errno(r
, "Failed to setup connection socket: %m");
182 * Set transmit timestamp, remember it; the server will send that back
183 * as the origin timestamp and we have an indication that this is the
184 * matching answer to our request.
186 * The actual value does not matter, We do not care about the correct
187 * NTP UINT_MAX fraction; we just pass the plain nanosecond value.
189 assert_se(clock_gettime(clock_boottime_or_monotonic(), &m
->trans_time_mon
) >= 0);
190 assert_se(clock_gettime(CLOCK_REALTIME
, &m
->trans_time
) >= 0);
191 ntpmsg
.trans_time
.sec
= htobe32(m
->trans_time
.tv_sec
+ OFFSET_1900_1970
);
192 ntpmsg
.trans_time
.frac
= htobe32(m
->trans_time
.tv_nsec
);
194 server_address_pretty(m
->current_server_address
, &pretty
);
196 len
= sendto(m
->server_socket
, &ntpmsg
, sizeof(ntpmsg
), MSG_DONTWAIT
, &m
->current_server_address
->sockaddr
.sa
, m
->current_server_address
->socklen
);
197 if (len
== sizeof(ntpmsg
)) {
199 log_debug("Sent NTP request to %s (%s).", strna(pretty
), m
->current_server_name
->string
);
201 log_debug_errno(errno
, "Sending NTP request to %s (%s) failed: %m", strna(pretty
), m
->current_server_name
->string
);
202 return manager_connect(m
);
205 /* re-arm timer with increasing timeout, in case the packets never arrive back */
206 if (m
->retry_interval
> 0) {
207 if (m
->retry_interval
< NTP_POLL_INTERVAL_MAX_SEC
* USEC_PER_SEC
)
208 m
->retry_interval
*= 2;
210 m
->retry_interval
= NTP_POLL_INTERVAL_MIN_SEC
* USEC_PER_SEC
;
212 r
= manager_arm_timer(m
, m
->retry_interval
);
214 return log_error_errno(r
, "Failed to rearm timer: %m");
217 if (m
->missed_replies
> NTP_MAX_MISSED_REPLIES
) {
218 r
= sd_event_add_time(
221 clock_boottime_or_monotonic(),
222 now(clock_boottime_or_monotonic()) + TIMEOUT_USEC
, 0,
225 return log_error_errno(r
, "Failed to arm timeout timer: %m");
231 static int manager_timer(sd_event_source
*source
, usec_t usec
, void *userdata
) {
232 Manager
*m
= userdata
;
236 return manager_send_request(m
);
239 static int manager_arm_timer(Manager
*m
, usec_t next
) {
245 m
->event_timer
= sd_event_source_unref(m
->event_timer
);
249 if (m
->event_timer
) {
250 r
= sd_event_source_set_time(m
->event_timer
, now(clock_boottime_or_monotonic()) + next
);
254 return sd_event_source_set_enabled(m
->event_timer
, SD_EVENT_ONESHOT
);
257 return sd_event_add_time(
260 clock_boottime_or_monotonic(),
261 now(clock_boottime_or_monotonic()) + next
, 0,
265 static int manager_clock_watch(sd_event_source
*source
, int fd
, uint32_t revents
, void *userdata
) {
266 Manager
*m
= userdata
;
271 manager_clock_watch_setup(m
);
273 /* skip our own jumps */
280 log_debug("System time changed. Resyncing.");
281 m
->poll_resync
= true;
283 return manager_send_request(m
);
286 /* wake up when the system time changes underneath us */
287 static int manager_clock_watch_setup(Manager
*m
) {
289 struct itimerspec its
= {
290 .it_value
.tv_sec
= TIME_T_MAX
297 m
->event_clock_watch
= sd_event_source_unref(m
->event_clock_watch
);
298 safe_close(m
->clock_watch_fd
);
300 m
->clock_watch_fd
= timerfd_create(CLOCK_REALTIME
, TFD_NONBLOCK
|TFD_CLOEXEC
);
301 if (m
->clock_watch_fd
< 0)
302 return log_error_errno(errno
, "Failed to create timerfd: %m");
304 if (timerfd_settime(m
->clock_watch_fd
, TFD_TIMER_ABSTIME
|TFD_TIMER_CANCEL_ON_SET
, &its
, NULL
) < 0)
305 return log_error_errno(errno
, "Failed to set up timerfd: %m");
307 r
= sd_event_add_io(m
->event
, &m
->event_clock_watch
, m
->clock_watch_fd
, EPOLLIN
, manager_clock_watch
, m
);
309 return log_error_errno(r
, "Failed to create clock watch event source: %m");
314 static int manager_adjust_clock(Manager
*m
, double offset
, int leap_sec
) {
315 struct timex tmx
= {};
321 * For small deltas, tell the kernel to gradually adjust the system
322 * clock to the NTP time, larger deltas are just directly set.
324 if (fabs(offset
) < NTP_MAX_ADJUST
) {
325 tmx
.modes
= ADJ_STATUS
| ADJ_NANO
| ADJ_OFFSET
| ADJ_TIMECONST
| ADJ_MAXERROR
| ADJ_ESTERROR
;
326 tmx
.status
= STA_PLL
;
327 tmx
.offset
= offset
* NSEC_PER_SEC
;
328 tmx
.constant
= log2i(m
->poll_interval_usec
/ USEC_PER_SEC
) - 4;
331 log_debug(" adjust (slew): %+.3f sec", offset
);
333 tmx
.modes
= ADJ_STATUS
| ADJ_NANO
| ADJ_SETOFFSET
| ADJ_MAXERROR
| ADJ_ESTERROR
;
335 /* ADJ_NANO uses nanoseconds in the microseconds field */
336 tmx
.time
.tv_sec
= (long)offset
;
337 tmx
.time
.tv_usec
= (offset
- tmx
.time
.tv_sec
) * NSEC_PER_SEC
;
341 /* the kernel expects -0.3s as {-1, 7000.000.000} */
342 if (tmx
.time
.tv_usec
< 0) {
343 tmx
.time
.tv_sec
-= 1;
344 tmx
.time
.tv_usec
+= NSEC_PER_SEC
;
348 log_debug(" adjust (jump): %+.3f sec", offset
);
352 * An unset STA_UNSYNC will enable the kernel's 11-minute mode,
353 * which syncs the system time periodically to the RTC.
355 * In case the RTC runs in local time, never touch the RTC,
356 * we have no way to properly handle daylight saving changes and
357 * mobile devices moving between time zones.
359 if (m
->rtc_local_time
)
360 tmx
.status
|= STA_UNSYNC
;
364 tmx
.status
|= STA_INS
;
367 tmx
.status
|= STA_DEL
;
371 r
= clock_adjtime(CLOCK_REALTIME
, &tmx
);
375 /* If touch fails, there isn't much we can do. Maybe it'll work next time. */
376 (void) touch("/var/lib/systemd/clock");
378 m
->drift_ppm
= tmx
.freq
/ 65536;
380 log_debug(" status : %04i %s\n"
381 " time now : %"PRI_TIME
".%03"PRI_USEC
"\n"
382 " constant : %"PRI_TIMEX
"\n"
383 " offset : %+.3f sec\n"
384 " freq offset : %+"PRI_TIMEX
" (%i ppm)\n",
385 tmx
.status
, tmx
.status
& STA_UNSYNC
? "unsync" : "sync",
386 tmx
.time
.tv_sec
, tmx
.time
.tv_usec
/ NSEC_PER_MSEC
,
388 (double)tmx
.offset
/ NSEC_PER_SEC
,
389 tmx
.freq
, m
->drift_ppm
);
394 static bool manager_sample_spike_detection(Manager
*m
, double offset
, double delay
) {
395 unsigned int i
, idx_cur
, idx_new
, idx_min
;
403 /* ignore initial sample */
404 if (m
->packet_count
== 1)
407 /* store the current data in our samples array */
408 idx_cur
= m
->samples_idx
;
409 idx_new
= (idx_cur
+ 1) % ELEMENTSOF(m
->samples
);
410 m
->samples_idx
= idx_new
;
411 m
->samples
[idx_new
].offset
= offset
;
412 m
->samples
[idx_new
].delay
= delay
;
414 /* calculate new jitter value from the RMS differences relative to the lowest delay sample */
415 jitter
= m
->samples_jitter
;
416 for (idx_min
= idx_cur
, i
= 0; i
< ELEMENTSOF(m
->samples
); i
++)
417 if (m
->samples
[i
].delay
> 0 && m
->samples
[i
].delay
< m
->samples
[idx_min
].delay
)
421 for (i
= 0; i
< ELEMENTSOF(m
->samples
); i
++)
422 j
+= pow(m
->samples
[i
].offset
- m
->samples
[idx_min
].offset
, 2);
423 m
->samples_jitter
= sqrt(j
/ (ELEMENTSOF(m
->samples
) - 1));
425 /* ignore samples when resyncing */
429 /* always accept offset if we are farther off than the round-trip delay */
430 if (fabs(offset
) > delay
)
433 /* we need a few samples before looking at them */
434 if (m
->packet_count
< 4)
437 /* do not accept anything worse than the maximum possible error of the best sample */
438 if (fabs(offset
) > m
->samples
[idx_min
].delay
)
441 /* compare the difference between the current offset to the previous offset and jitter */
442 return fabs(offset
- m
->samples
[idx_cur
].offset
) > 3 * jitter
;
445 static void manager_adjust_poll(Manager
*m
, double offset
, bool spike
) {
448 if (m
->poll_resync
) {
449 m
->poll_interval_usec
= NTP_POLL_INTERVAL_MIN_SEC
* USEC_PER_SEC
;
450 m
->poll_resync
= false;
454 /* set to minimal poll interval */
455 if (!spike
&& fabs(offset
) > NTP_ACCURACY_SEC
) {
456 m
->poll_interval_usec
= NTP_POLL_INTERVAL_MIN_SEC
* USEC_PER_SEC
;
460 /* increase polling interval */
461 if (fabs(offset
) < NTP_ACCURACY_SEC
* 0.25) {
462 if (m
->poll_interval_usec
< NTP_POLL_INTERVAL_MAX_SEC
* USEC_PER_SEC
)
463 m
->poll_interval_usec
*= 2;
467 /* decrease polling interval */
468 if (spike
|| fabs(offset
) > NTP_ACCURACY_SEC
* 0.75) {
469 if (m
->poll_interval_usec
> NTP_POLL_INTERVAL_MIN_SEC
* USEC_PER_SEC
)
470 m
->poll_interval_usec
/= 2;
475 static int manager_receive_response(sd_event_source
*source
, int fd
, uint32_t revents
, void *userdata
) {
476 Manager
*m
= userdata
;
477 struct ntp_msg ntpmsg
;
481 .iov_len
= sizeof(ntpmsg
),
484 struct cmsghdr cmsghdr
;
485 uint8_t buf
[CMSG_SPACE(sizeof(struct timeval
))];
487 union sockaddr_union server_addr
;
488 struct msghdr msghdr
= {
491 .msg_control
= &control
,
492 .msg_controllen
= sizeof(control
),
493 .msg_name
= &server_addr
,
494 .msg_namelen
= sizeof(server_addr
),
496 struct cmsghdr
*cmsg
;
497 struct timespec
*recv_time
;
499 double origin
, receive
, trans
, dest
;
500 double delay
, offset
;
501 double root_distance
;
509 if (revents
& (EPOLLHUP
|EPOLLERR
)) {
510 log_warning("Server connection returned error.");
511 return manager_connect(m
);
514 len
= recvmsg(fd
, &msghdr
, MSG_DONTWAIT
);
519 log_warning("Error receiving message. Disconnecting.");
520 return manager_connect(m
);
523 /* Too short or too long packet? */
524 if (iov
.iov_len
< sizeof(struct ntp_msg
) || (msghdr
.msg_flags
& MSG_TRUNC
)) {
525 log_warning("Invalid response from server. Disconnecting.");
526 return manager_connect(m
);
529 if (!m
->current_server_name
||
530 !m
->current_server_address
||
531 !sockaddr_equal(&server_addr
, &m
->current_server_address
->sockaddr
)) {
532 log_debug("Response from unknown server.");
537 CMSG_FOREACH(cmsg
, &msghdr
) {
538 if (cmsg
->cmsg_level
!= SOL_SOCKET
)
541 switch (cmsg
->cmsg_type
) {
542 case SCM_TIMESTAMPNS
:
543 recv_time
= (struct timespec
*) CMSG_DATA(cmsg
);
548 log_error("Invalid packet timestamp.");
553 log_debug("Unexpected reply. Ignoring.");
557 m
->missed_replies
= 0;
559 /* check our "time cookie" (we just stored nanoseconds in the fraction field) */
560 if (be32toh(ntpmsg
.origin_time
.sec
) != m
->trans_time
.tv_sec
+ OFFSET_1900_1970
||
561 be32toh(ntpmsg
.origin_time
.frac
) != m
->trans_time
.tv_nsec
) {
562 log_debug("Invalid reply; not our transmit time. Ignoring.");
566 m
->event_timeout
= sd_event_source_unref(m
->event_timeout
);
568 if (be32toh(ntpmsg
.recv_time
.sec
) < TIME_EPOCH
+ OFFSET_1900_1970
||
569 be32toh(ntpmsg
.trans_time
.sec
) < TIME_EPOCH
+ OFFSET_1900_1970
) {
570 log_debug("Invalid reply, returned times before epoch. Ignoring.");
571 return manager_connect(m
);
574 if (NTP_FIELD_LEAP(ntpmsg
.field
) == NTP_LEAP_NOTINSYNC
||
575 ntpmsg
.stratum
== 0 || ntpmsg
.stratum
>= 16) {
576 log_debug("Server is not synchronized. Disconnecting.");
577 return manager_connect(m
);
580 if (!IN_SET(NTP_FIELD_VERSION(ntpmsg
.field
), 3, 4)) {
581 log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg
.field
));
582 return manager_connect(m
);
585 if (NTP_FIELD_MODE(ntpmsg
.field
) != NTP_MODE_SERVER
) {
586 log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg
.field
));
587 return manager_connect(m
);
590 root_distance
= ntp_ts_short_to_d(&ntpmsg
.root_delay
) / 2 + ntp_ts_short_to_d(&ntpmsg
.root_dispersion
);
591 if (root_distance
> NTP_MAX_ROOT_DISTANCE
) {
592 log_debug("Server has too large root distance. Disconnecting.");
593 return manager_connect(m
);
598 m
->retry_interval
= 0;
601 manager_listen_stop(m
);
603 /* announce leap seconds */
604 if (NTP_FIELD_LEAP(ntpmsg
.field
) & NTP_LEAP_PLUSSEC
)
606 else if (NTP_FIELD_LEAP(ntpmsg
.field
) & NTP_LEAP_MINUSSEC
)
612 * "Timestamp Name ID When Generated
613 * ------------------------------------------------------------
614 * Originate Timestamp T1 time request sent by client
615 * Receive Timestamp T2 time request received by server
616 * Transmit Timestamp T3 time reply sent by server
617 * Destination Timestamp T4 time reply received by client
619 * The round-trip delay, d, and system clock offset, t, are defined as:
620 * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
622 origin
= ts_to_d(&m
->trans_time
) + OFFSET_1900_1970
;
623 receive
= ntp_ts_to_d(&ntpmsg
.recv_time
);
624 trans
= ntp_ts_to_d(&ntpmsg
.trans_time
);
625 dest
= ts_to_d(recv_time
) + OFFSET_1900_1970
;
627 offset
= ((receive
- origin
) + (trans
- dest
)) / 2;
628 delay
= (dest
- origin
) - (trans
- receive
);
630 spike
= manager_sample_spike_detection(m
, offset
, delay
);
632 manager_adjust_poll(m
, offset
, spike
);
634 log_debug("NTP response:\n"
639 " precision : %.6f sec (%d)\n"
640 " root distance: %.6f sec\n"
641 " reference : %.4s\n"
646 " offset : %+.3f sec\n"
647 " delay : %+.3f sec\n"
648 " packet count : %"PRIu64
"\n"
650 " poll interval: " USEC_FMT
"\n",
651 NTP_FIELD_LEAP(ntpmsg
.field
),
652 NTP_FIELD_VERSION(ntpmsg
.field
),
653 NTP_FIELD_MODE(ntpmsg
.field
),
655 exp2(ntpmsg
.precision
), ntpmsg
.precision
,
657 ntpmsg
.stratum
== 1 ? ntpmsg
.refid
: "n/a",
658 origin
- OFFSET_1900_1970
,
659 receive
- OFFSET_1900_1970
,
660 trans
- OFFSET_1900_1970
,
661 dest
- OFFSET_1900_1970
,
664 m
->samples_jitter
, spike
? " spike" : "",
665 m
->poll_interval_usec
/ USEC_PER_SEC
);
669 r
= manager_adjust_clock(m
, offset
, leap_sec
);
671 log_error_errno(r
, "Failed to call clock_adjtime(): %m");
674 log_debug("interval/delta/delay/jitter/drift " USEC_FMT
"s/%+.3fs/%.3fs/%.3fs/%+ippm%s",
675 m
->poll_interval_usec
/ USEC_PER_SEC
, offset
, delay
, m
->samples_jitter
, m
->drift_ppm
,
676 spike
? " (ignored)" : "");
679 _cleanup_free_
char *pretty
= NULL
;
683 server_address_pretty(m
->current_server_address
, &pretty
);
684 log_info("Synchronized to time server %s (%s).", strna(pretty
), m
->current_server_name
->string
);
685 sd_notifyf(false, "STATUS=Synchronized to time server %s (%s).", strna(pretty
), m
->current_server_name
->string
);
688 r
= manager_arm_timer(m
, m
->poll_interval_usec
);
690 return log_error_errno(r
, "Failed to rearm timer: %m");
695 static int manager_listen_setup(Manager
*m
) {
696 union sockaddr_union addr
= {};
697 static const int tos
= IPTOS_LOWDELAY
;
698 static const int on
= 1;
703 if (m
->server_socket
>= 0)
706 assert(!m
->event_receive
);
707 assert(m
->current_server_address
);
709 addr
.sa
.sa_family
= m
->current_server_address
->sockaddr
.sa
.sa_family
;
711 m
->server_socket
= socket(addr
.sa
.sa_family
, SOCK_DGRAM
| SOCK_CLOEXEC
, 0);
712 if (m
->server_socket
< 0)
715 r
= bind(m
->server_socket
, &addr
.sa
, m
->current_server_address
->socklen
);
719 r
= setsockopt(m
->server_socket
, SOL_SOCKET
, SO_TIMESTAMPNS
, &on
, sizeof(on
));
723 (void) setsockopt(m
->server_socket
, IPPROTO_IP
, IP_TOS
, &tos
, sizeof(tos
));
725 return sd_event_add_io(m
->event
, &m
->event_receive
, m
->server_socket
, EPOLLIN
, manager_receive_response
, m
);
728 static void manager_listen_stop(Manager
*m
) {
731 m
->event_receive
= sd_event_source_unref(m
->event_receive
);
732 m
->server_socket
= safe_close(m
->server_socket
);
735 static int manager_begin(Manager
*m
) {
736 _cleanup_free_
char *pretty
= NULL
;
740 assert_return(m
->current_server_name
, -EHOSTUNREACH
);
741 assert_return(m
->current_server_address
, -EHOSTUNREACH
);
744 m
->missed_replies
= NTP_MAX_MISSED_REPLIES
;
745 if (m
->poll_interval_usec
== 0)
746 m
->poll_interval_usec
= NTP_POLL_INTERVAL_MIN_SEC
* USEC_PER_SEC
;
748 server_address_pretty(m
->current_server_address
, &pretty
);
749 log_debug("Connecting to time server %s (%s).", strna(pretty
), m
->current_server_name
->string
);
750 sd_notifyf(false, "STATUS=Connecting to time server %s (%s).", strna(pretty
), m
->current_server_name
->string
);
752 r
= manager_clock_watch_setup(m
);
756 return manager_send_request(m
);
759 void manager_set_server_name(Manager
*m
, ServerName
*n
) {
762 if (m
->current_server_name
== n
)
765 m
->current_server_name
= n
;
766 m
->current_server_address
= NULL
;
768 manager_disconnect(m
);
771 log_debug("Selected server %s.", n
->string
);
774 void manager_set_server_address(Manager
*m
, ServerAddress
*a
) {
777 if (m
->current_server_address
== a
)
780 m
->current_server_address
= a
;
781 /* If a is NULL, we are just clearing the address, without
782 * changing the name. Keep the existing name in that case. */
784 m
->current_server_name
= a
->name
;
786 manager_disconnect(m
);
789 _cleanup_free_
char *pretty
= NULL
;
790 server_address_pretty(a
, &pretty
);
791 log_debug("Selected address %s of server %s.", strna(pretty
), a
->name
->string
);
795 static int manager_resolve_handler(sd_resolve_query
*q
, int ret
, const struct addrinfo
*ai
, void *userdata
) {
796 Manager
*m
= userdata
;
801 assert(m
->current_server_name
);
803 m
->resolve_query
= sd_resolve_query_unref(m
->resolve_query
);
806 log_debug("Failed to resolve %s: %s", m
->current_server_name
->string
, gai_strerror(ret
));
809 return manager_connect(m
);
812 for (; ai
; ai
= ai
->ai_next
) {
813 _cleanup_free_
char *pretty
= NULL
;
817 assert(ai
->ai_addrlen
>= offsetof(struct sockaddr
, sa_data
));
819 if (!IN_SET(ai
->ai_addr
->sa_family
, AF_INET
, AF_INET6
)) {
820 log_warning("Unsuitable address protocol for %s", m
->current_server_name
->string
);
824 r
= server_address_new(m
->current_server_name
, &a
, (const union sockaddr_union
*) ai
->ai_addr
, ai
->ai_addrlen
);
826 return log_error_errno(r
, "Failed to add server address: %m");
828 server_address_pretty(a
, &pretty
);
829 log_debug("Resolved address %s for %s.", pretty
, m
->current_server_name
->string
);
832 if (!m
->current_server_name
->addresses
) {
833 log_error("Failed to find suitable address for host %s.", m
->current_server_name
->string
);
836 return manager_connect(m
);
839 manager_set_server_address(m
, m
->current_server_name
->addresses
);
841 return manager_begin(m
);
844 static int manager_retry_connect(sd_event_source
*source
, usec_t usec
, void *userdata
) {
845 Manager
*m
= userdata
;
849 return manager_connect(m
);
852 int manager_connect(Manager
*m
) {
857 manager_disconnect(m
);
859 m
->event_retry
= sd_event_source_unref(m
->event_retry
);
860 if (!ratelimit_test(&m
->ratelimit
)) {
861 log_debug("Slowing down attempts to contact servers.");
863 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
);
865 return log_error_errno(r
, "Failed to create retry timer: %m");
870 /* If we already are operating on some address, switch to the
872 if (m
->current_server_address
&& m
->current_server_address
->addresses_next
)
873 manager_set_server_address(m
, m
->current_server_address
->addresses_next
);
875 struct addrinfo hints
= {
876 .ai_flags
= AI_NUMERICSERV
|AI_ADDRCONFIG
,
877 .ai_socktype
= SOCK_DGRAM
,
880 /* Hmm, we are through all addresses, let's look for the next host instead */
881 if (m
->current_server_name
&& m
->current_server_name
->names_next
)
882 manager_set_server_name(m
, m
->current_server_name
->names_next
);
887 /* Our current server name list is exhausted,
888 * let's find the next one to iterate. First
889 * we try the system list, then the link list.
890 * After having processed the link list we
891 * jump back to the system list. However, if
892 * both lists are empty, we change to the
894 if (!m
->current_server_name
|| m
->current_server_name
->type
== SERVER_LINK
) {
895 f
= m
->system_servers
;
901 f
= m
->system_servers
;
907 f
= m
->fallback_servers
;
910 manager_set_server_name(m
, NULL
);
911 log_debug("No server found.");
915 if (restart
&& !m
->exhausted_servers
&& m
->poll_interval_usec
) {
916 log_debug("Waiting after exhausting servers.");
917 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
);
919 return log_error_errno(r
, "Failed to create retry timer: %m");
921 m
->exhausted_servers
= true;
923 /* Increase the polling interval */
924 if (m
->poll_interval_usec
< NTP_POLL_INTERVAL_MAX_SEC
* USEC_PER_SEC
)
925 m
->poll_interval_usec
*= 2;
930 m
->exhausted_servers
= false;
932 manager_set_server_name(m
, f
);
935 /* Tell the resolver to reread /etc/resolv.conf, in
936 * case it changed. */
939 /* Flush out any previously resolved addresses */
940 server_name_flush_addresses(m
->current_server_name
);
942 log_debug("Resolving %s...", m
->current_server_name
->string
);
944 r
= sd_resolve_getaddrinfo(m
->resolve
, &m
->resolve_query
, m
->current_server_name
->string
, "123", &hints
, manager_resolve_handler
, m
);
946 return log_error_errno(r
, "Failed to create resolver: %m");
951 r
= manager_begin(m
);
958 void manager_disconnect(Manager
*m
) {
961 m
->resolve_query
= sd_resolve_query_unref(m
->resolve_query
);
963 m
->event_timer
= sd_event_source_unref(m
->event_timer
);
965 manager_listen_stop(m
);
967 m
->event_clock_watch
= sd_event_source_unref(m
->event_clock_watch
);
968 m
->clock_watch_fd
= safe_close(m
->clock_watch_fd
);
970 m
->event_timeout
= sd_event_source_unref(m
->event_timeout
);
972 sd_notifyf(false, "STATUS=Idle.");
975 void manager_flush_server_names(Manager
*m
, ServerType t
) {
978 if (t
== SERVER_SYSTEM
)
979 while (m
->system_servers
)
980 server_name_free(m
->system_servers
);
982 if (t
== SERVER_LINK
)
983 while (m
->link_servers
)
984 server_name_free(m
->link_servers
);
986 if (t
== SERVER_FALLBACK
)
987 while (m
->fallback_servers
)
988 server_name_free(m
->fallback_servers
);
991 void manager_free(Manager
*m
) {
995 manager_disconnect(m
);
996 manager_flush_server_names(m
, SERVER_SYSTEM
);
997 manager_flush_server_names(m
, SERVER_LINK
);
998 manager_flush_server_names(m
, SERVER_FALLBACK
);
1000 sd_event_source_unref(m
->event_retry
);
1002 sd_event_source_unref(m
->network_event_source
);
1003 sd_network_monitor_unref(m
->network_monitor
);
1005 sd_resolve_unref(m
->resolve
);
1006 sd_event_unref(m
->event
);
1011 static int manager_network_read_link_servers(Manager
*m
) {
1012 _cleanup_strv_free_
char **ntp
= NULL
;
1019 r
= sd_network_get_ntp(&ntp
);
1023 LIST_FOREACH(names
, n
, m
->link_servers
)
1026 STRV_FOREACH(i
, ntp
) {
1029 LIST_FOREACH(names
, n
, m
->link_servers
)
1030 if (streq(n
->string
, *i
)) {
1037 r
= server_name_new(m
, NULL
, SERVER_LINK
, *i
);
1043 LIST_FOREACH_SAFE(names
, n
, nx
, m
->link_servers
)
1045 server_name_free(n
);
1050 manager_flush_server_names(m
, SERVER_LINK
);
1054 static int manager_network_event_handler(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
1055 Manager
*m
= userdata
;
1056 bool connected
, online
;
1061 sd_network_monitor_flush(m
->network_monitor
);
1063 manager_network_read_link_servers(m
);
1065 /* check if the machine is online */
1066 online
= network_is_online();
1068 /* check if the client is currently connected */
1069 connected
= m
->server_socket
>= 0 || m
->resolve_query
|| m
->exhausted_servers
;
1071 if (connected
&& !online
) {
1072 log_info("No network connectivity, watching for changes.");
1073 manager_disconnect(m
);
1075 } else if (!connected
&& online
) {
1076 log_info("Network configuration changed, trying to establish connection.");
1078 if (m
->current_server_address
)
1079 r
= manager_begin(m
);
1081 r
= manager_connect(m
);
1089 static int manager_network_monitor_listen(Manager
*m
) {
1094 r
= sd_network_monitor_new(&m
->network_monitor
, NULL
);
1098 fd
= sd_network_monitor_get_fd(m
->network_monitor
);
1102 events
= sd_network_monitor_get_events(m
->network_monitor
);
1106 r
= sd_event_add_io(m
->event
, &m
->network_event_source
, fd
, events
, manager_network_event_handler
, m
);
1113 int manager_new(Manager
**ret
) {
1114 _cleanup_(manager_freep
) Manager
*m
= NULL
;
1119 m
= new0(Manager
, 1);
1123 m
->server_socket
= m
->clock_watch_fd
= -1;
1125 RATELIMIT_INIT(m
->ratelimit
, RATELIMIT_INTERVAL_USEC
, RATELIMIT_BURST
);
1127 r
= sd_event_default(&m
->event
);
1131 sd_event_add_signal(m
->event
, NULL
, SIGTERM
, NULL
, NULL
);
1132 sd_event_add_signal(m
->event
, NULL
, SIGINT
, NULL
, NULL
);
1134 sd_event_set_watchdog(m
->event
, true);
1136 r
= sd_resolve_default(&m
->resolve
);
1140 r
= sd_resolve_attach_event(m
->resolve
, m
->event
, 0);
1144 r
= manager_network_monitor_listen(m
);
1148 manager_network_read_link_servers(m
);