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[thirdparty/systemd.git] / src / timesync / timesyncd-manager.c
1 /* SPDX-License-Identifier: LGPL-2.1+ */
2 /***
3 This file is part of systemd.
4
5 Copyright 2014 Kay Sievers, Lennart Poettering
6 ***/
7
8 #include <errno.h>
9 #include <math.h>
10 #include <netinet/in.h>
11 #include <netinet/ip.h>
12 #include <resolv.h>
13 #include <stdlib.h>
14 #include <sys/socket.h>
15 #include <sys/timerfd.h>
16 #include <sys/timex.h>
17 #include <sys/types.h>
18 #include <time.h>
19
20 #include "sd-daemon.h"
21
22 #include "alloc-util.h"
23 #include "fd-util.h"
24 #include "fs-util.h"
25 #include "list.h"
26 #include "log.h"
27 #include "missing.h"
28 #include "network-util.h"
29 #include "ratelimit.h"
30 #include "socket-util.h"
31 #include "sparse-endian.h"
32 #include "string-util.h"
33 #include "strv.h"
34 #include "time-util.h"
35 #include "timesyncd-conf.h"
36 #include "timesyncd-manager.h"
37 #include "util.h"
38
39 #ifndef ADJ_SETOFFSET
40 #define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
41 #endif
42
43 /* expected accuracy of time synchronization; used to adjust the poll interval */
44 #define NTP_ACCURACY_SEC 0.2
45
46 /*
47 * Maximum delta in seconds which the system clock is gradually adjusted
48 * (slewed) to approach the network time. Deltas larger that this are set by
49 * letting the system time jump. The kernel's limit for adjtime is 0.5s.
50 */
51 #define NTP_MAX_ADJUST 0.4
52
53 /* NTP protocol, packet header */
54 #define NTP_LEAP_PLUSSEC 1
55 #define NTP_LEAP_MINUSSEC 2
56 #define NTP_LEAP_NOTINSYNC 3
57 #define NTP_MODE_CLIENT 3
58 #define NTP_MODE_SERVER 4
59 #define NTP_FIELD_LEAP(f) (((f) >> 6) & 3)
60 #define NTP_FIELD_VERSION(f) (((f) >> 3) & 7)
61 #define NTP_FIELD_MODE(f) ((f) & 7)
62 #define NTP_FIELD(l, v, m) (((l) << 6) | ((v) << 3) | (m))
63
64 /* Default of maximum acceptable root distance in microseconds. */
65 #define NTP_MAX_ROOT_DISTANCE (5 * USEC_PER_SEC)
66
67 /* Maximum number of missed replies before selecting another source. */
68 #define NTP_MAX_MISSED_REPLIES 2
69
70 /*
71 * "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
72 * in seconds relative to 0h on 1 January 1900."
73 */
74 #define OFFSET_1900_1970 UINT64_C(2208988800)
75
76 #define RETRY_USEC (30*USEC_PER_SEC)
77 #define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
78 #define RATELIMIT_BURST 10
79
80 #define TIMEOUT_USEC (10*USEC_PER_SEC)
81
82 struct ntp_ts {
83 be32_t sec;
84 be32_t frac;
85 } _packed_;
86
87 struct ntp_ts_short {
88 be16_t sec;
89 be16_t frac;
90 } _packed_;
91
92 struct ntp_msg {
93 uint8_t field;
94 uint8_t stratum;
95 int8_t poll;
96 int8_t precision;
97 struct ntp_ts_short root_delay;
98 struct ntp_ts_short root_dispersion;
99 char refid[4];
100 struct ntp_ts reference_time;
101 struct ntp_ts origin_time;
102 struct ntp_ts recv_time;
103 struct ntp_ts trans_time;
104 } _packed_;
105
106 static int manager_arm_timer(Manager *m, usec_t next);
107 static int manager_clock_watch_setup(Manager *m);
108 static int manager_listen_setup(Manager *m);
109 static void manager_listen_stop(Manager *m);
110
111 static double ntp_ts_short_to_d(const struct ntp_ts_short *ts) {
112 return be16toh(ts->sec) + (be16toh(ts->frac) / 65536.0);
113 }
114
115 static double ntp_ts_to_d(const struct ntp_ts *ts) {
116 return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
117 }
118
119 static double ts_to_d(const struct timespec *ts) {
120 return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
121 }
122
123 static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
124 _cleanup_free_ char *pretty = NULL;
125 Manager *m = userdata;
126
127 assert(m);
128 assert(m->current_server_name);
129 assert(m->current_server_address);
130
131 server_address_pretty(m->current_server_address, &pretty);
132 log_info("Timed out waiting for reply from %s (%s).", strna(pretty), m->current_server_name->string);
133
134 return manager_connect(m);
135 }
136
137 static int manager_send_request(Manager *m) {
138 _cleanup_free_ char *pretty = NULL;
139 struct ntp_msg ntpmsg = {
140 /*
141 * "The client initializes the NTP message header, sends the request
142 * to the server, and strips the time of day from the Transmit
143 * Timestamp field of the reply. For this purpose, all the NTP
144 * header fields are set to 0, except the Mode, VN, and optional
145 * Transmit Timestamp fields."
146 */
147 .field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
148 };
149 ssize_t len;
150 int r;
151
152 assert(m);
153 assert(m->current_server_name);
154 assert(m->current_server_address);
155
156 m->event_timeout = sd_event_source_unref(m->event_timeout);
157
158 r = manager_listen_setup(m);
159 if (r < 0)
160 return log_warning_errno(r, "Failed to setup connection socket: %m");
161
162 /*
163 * Set transmit timestamp, remember it; the server will send that back
164 * as the origin timestamp and we have an indication that this is the
165 * matching answer to our request.
166 *
167 * The actual value does not matter, We do not care about the correct
168 * NTP UINT_MAX fraction; we just pass the plain nanosecond value.
169 */
170 assert_se(clock_gettime(clock_boottime_or_monotonic(), &m->trans_time_mon) >= 0);
171 assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
172 ntpmsg.trans_time.sec = htobe32(m->trans_time.tv_sec + OFFSET_1900_1970);
173 ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
174
175 server_address_pretty(m->current_server_address, &pretty);
176
177 len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
178 if (len == sizeof(ntpmsg)) {
179 m->pending = true;
180 log_debug("Sent NTP request to %s (%s).", strna(pretty), m->current_server_name->string);
181 } else {
182 log_debug_errno(errno, "Sending NTP request to %s (%s) failed: %m", strna(pretty), m->current_server_name->string);
183 return manager_connect(m);
184 }
185
186 /* re-arm timer with increasing timeout, in case the packets never arrive back */
187 if (m->retry_interval > 0) {
188 if (m->retry_interval < m->poll_interval_max_usec)
189 m->retry_interval *= 2;
190 } else
191 m->retry_interval = m->poll_interval_min_usec;
192
193 r = manager_arm_timer(m, m->retry_interval);
194 if (r < 0)
195 return log_error_errno(r, "Failed to rearm timer: %m");
196
197 m->missed_replies++;
198 if (m->missed_replies > NTP_MAX_MISSED_REPLIES) {
199 r = sd_event_add_time(
200 m->event,
201 &m->event_timeout,
202 clock_boottime_or_monotonic(),
203 now(clock_boottime_or_monotonic()) + TIMEOUT_USEC, 0,
204 manager_timeout, m);
205 if (r < 0)
206 return log_error_errno(r, "Failed to arm timeout timer: %m");
207 }
208
209 return 0;
210 }
211
212 static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
213 Manager *m = userdata;
214
215 assert(m);
216
217 return manager_send_request(m);
218 }
219
220 static int manager_arm_timer(Manager *m, usec_t next) {
221 int r;
222
223 assert(m);
224
225 if (next == 0) {
226 m->event_timer = sd_event_source_unref(m->event_timer);
227 return 0;
228 }
229
230 if (m->event_timer) {
231 r = sd_event_source_set_time(m->event_timer, now(clock_boottime_or_monotonic()) + next);
232 if (r < 0)
233 return r;
234
235 return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
236 }
237
238 return sd_event_add_time(
239 m->event,
240 &m->event_timer,
241 clock_boottime_or_monotonic(),
242 now(clock_boottime_or_monotonic()) + next, 0,
243 manager_timer, m);
244 }
245
246 static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
247 Manager *m = userdata;
248
249 assert(m);
250
251 /* rearm timer */
252 manager_clock_watch_setup(m);
253
254 /* skip our own jumps */
255 if (m->jumped) {
256 m->jumped = false;
257 return 0;
258 }
259
260 /* resync */
261 log_debug("System time changed. Resyncing.");
262 m->poll_resync = true;
263
264 return manager_send_request(m);
265 }
266
267 /* wake up when the system time changes underneath us */
268 static int manager_clock_watch_setup(Manager *m) {
269
270 struct itimerspec its = {
271 .it_value.tv_sec = TIME_T_MAX
272 };
273
274 int r;
275
276 assert(m);
277
278 m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
279 safe_close(m->clock_watch_fd);
280
281 m->clock_watch_fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
282 if (m->clock_watch_fd < 0)
283 return log_error_errno(errno, "Failed to create timerfd: %m");
284
285 if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0)
286 return log_error_errno(errno, "Failed to set up timerfd: %m");
287
288 r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, manager_clock_watch, m);
289 if (r < 0)
290 return log_error_errno(r, "Failed to create clock watch event source: %m");
291
292 return 0;
293 }
294
295 static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
296 struct timex tmx = {};
297 int r;
298
299 assert(m);
300
301 /*
302 * For small deltas, tell the kernel to gradually adjust the system
303 * clock to the NTP time, larger deltas are just directly set.
304 */
305 if (fabs(offset) < NTP_MAX_ADJUST) {
306 tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR;
307 tmx.status = STA_PLL;
308 tmx.offset = offset * NSEC_PER_SEC;
309 tmx.constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4;
310 tmx.maxerror = 0;
311 tmx.esterror = 0;
312 log_debug(" adjust (slew): %+.3f sec", offset);
313 } else {
314 tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET | ADJ_MAXERROR | ADJ_ESTERROR;
315
316 /* ADJ_NANO uses nanoseconds in the microseconds field */
317 tmx.time.tv_sec = (long)offset;
318 tmx.time.tv_usec = (offset - tmx.time.tv_sec) * NSEC_PER_SEC;
319 tmx.maxerror = 0;
320 tmx.esterror = 0;
321
322 /* the kernel expects -0.3s as {-1, 7000.000.000} */
323 if (tmx.time.tv_usec < 0) {
324 tmx.time.tv_sec -= 1;
325 tmx.time.tv_usec += NSEC_PER_SEC;
326 }
327
328 m->jumped = true;
329 log_debug(" adjust (jump): %+.3f sec", offset);
330 }
331
332 /*
333 * An unset STA_UNSYNC will enable the kernel's 11-minute mode,
334 * which syncs the system time periodically to the RTC.
335 *
336 * In case the RTC runs in local time, never touch the RTC,
337 * we have no way to properly handle daylight saving changes and
338 * mobile devices moving between time zones.
339 */
340 if (m->rtc_local_time)
341 tmx.status |= STA_UNSYNC;
342
343 switch (leap_sec) {
344 case 1:
345 tmx.status |= STA_INS;
346 break;
347 case -1:
348 tmx.status |= STA_DEL;
349 break;
350 }
351
352 r = clock_adjtime(CLOCK_REALTIME, &tmx);
353 if (r < 0)
354 return -errno;
355
356 /* If touch fails, there isn't much we can do. Maybe it'll work next time. */
357 (void) touch("/var/lib/systemd/timesync/clock");
358
359 m->drift_ppm = tmx.freq / 65536;
360
361 log_debug(" status : %04i %s\n"
362 " time now : %"PRI_TIME".%03"PRI_USEC"\n"
363 " constant : %"PRI_TIMEX"\n"
364 " offset : %+.3f sec\n"
365 " freq offset : %+"PRI_TIMEX" (%i ppm)\n",
366 tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
367 tmx.time.tv_sec, tmx.time.tv_usec / NSEC_PER_MSEC,
368 tmx.constant,
369 (double)tmx.offset / NSEC_PER_SEC,
370 tmx.freq, m->drift_ppm);
371
372 return 0;
373 }
374
375 static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
376 unsigned int i, idx_cur, idx_new, idx_min;
377 double jitter;
378 double j;
379
380 assert(m);
381
382 m->packet_count++;
383
384 /* ignore initial sample */
385 if (m->packet_count == 1)
386 return false;
387
388 /* store the current data in our samples array */
389 idx_cur = m->samples_idx;
390 idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
391 m->samples_idx = idx_new;
392 m->samples[idx_new].offset = offset;
393 m->samples[idx_new].delay = delay;
394
395 /* calculate new jitter value from the RMS differences relative to the lowest delay sample */
396 jitter = m->samples_jitter;
397 for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
398 if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
399 idx_min = i;
400
401 j = 0;
402 for (i = 0; i < ELEMENTSOF(m->samples); i++)
403 j += pow(m->samples[i].offset - m->samples[idx_min].offset, 2);
404 m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
405
406 /* ignore samples when resyncing */
407 if (m->poll_resync)
408 return false;
409
410 /* always accept offset if we are farther off than the round-trip delay */
411 if (fabs(offset) > delay)
412 return false;
413
414 /* we need a few samples before looking at them */
415 if (m->packet_count < 4)
416 return false;
417
418 /* do not accept anything worse than the maximum possible error of the best sample */
419 if (fabs(offset) > m->samples[idx_min].delay)
420 return true;
421
422 /* compare the difference between the current offset to the previous offset and jitter */
423 return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
424 }
425
426 static void manager_adjust_poll(Manager *m, double offset, bool spike) {
427 assert(m);
428
429 if (m->poll_resync) {
430 m->poll_interval_usec = m->poll_interval_min_usec;
431 m->poll_resync = false;
432 return;
433 }
434
435 /* set to minimal poll interval */
436 if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
437 m->poll_interval_usec = m->poll_interval_min_usec;
438 return;
439 }
440
441 /* increase polling interval */
442 if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
443 if (m->poll_interval_usec < m->poll_interval_max_usec)
444 m->poll_interval_usec *= 2;
445 return;
446 }
447
448 /* decrease polling interval */
449 if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
450 if (m->poll_interval_usec > m->poll_interval_min_usec)
451 m->poll_interval_usec /= 2;
452 return;
453 }
454 }
455
456 static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
457 Manager *m = userdata;
458 struct ntp_msg ntpmsg;
459
460 struct iovec iov = {
461 .iov_base = &ntpmsg,
462 .iov_len = sizeof(ntpmsg),
463 };
464 union {
465 struct cmsghdr cmsghdr;
466 uint8_t buf[CMSG_SPACE(sizeof(struct timeval))];
467 } control;
468 union sockaddr_union server_addr;
469 struct msghdr msghdr = {
470 .msg_iov = &iov,
471 .msg_iovlen = 1,
472 .msg_control = &control,
473 .msg_controllen = sizeof(control),
474 .msg_name = &server_addr,
475 .msg_namelen = sizeof(server_addr),
476 };
477 struct cmsghdr *cmsg;
478 struct timespec *recv_time = NULL;
479 ssize_t len;
480 double origin, receive, trans, dest;
481 double delay, offset;
482 double root_distance;
483 bool spike;
484 int leap_sec;
485 int r;
486
487 assert(source);
488 assert(m);
489
490 if (revents & (EPOLLHUP|EPOLLERR)) {
491 log_warning("Server connection returned error.");
492 return manager_connect(m);
493 }
494
495 len = recvmsg(fd, &msghdr, MSG_DONTWAIT);
496 if (len < 0) {
497 if (errno == EAGAIN)
498 return 0;
499
500 log_warning("Error receiving message. Disconnecting.");
501 return manager_connect(m);
502 }
503
504 /* Too short or too long packet? */
505 if (iov.iov_len < sizeof(struct ntp_msg) || (msghdr.msg_flags & MSG_TRUNC)) {
506 log_warning("Invalid response from server. Disconnecting.");
507 return manager_connect(m);
508 }
509
510 if (!m->current_server_name ||
511 !m->current_server_address ||
512 !sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
513 log_debug("Response from unknown server.");
514 return 0;
515 }
516
517 CMSG_FOREACH(cmsg, &msghdr) {
518 if (cmsg->cmsg_level != SOL_SOCKET)
519 continue;
520
521 switch (cmsg->cmsg_type) {
522 case SCM_TIMESTAMPNS:
523 recv_time = (struct timespec *) CMSG_DATA(cmsg);
524 break;
525 }
526 }
527 if (!recv_time) {
528 log_error("Invalid packet timestamp.");
529 return -EINVAL;
530 }
531
532 if (!m->pending) {
533 log_debug("Unexpected reply. Ignoring.");
534 return 0;
535 }
536
537 m->missed_replies = 0;
538
539 /* check our "time cookie" (we just stored nanoseconds in the fraction field) */
540 if (be32toh(ntpmsg.origin_time.sec) != m->trans_time.tv_sec + OFFSET_1900_1970 ||
541 be32toh(ntpmsg.origin_time.frac) != (unsigned long) m->trans_time.tv_nsec) {
542 log_debug("Invalid reply; not our transmit time. Ignoring.");
543 return 0;
544 }
545
546 m->event_timeout = sd_event_source_unref(m->event_timeout);
547
548 if (be32toh(ntpmsg.recv_time.sec) < TIME_EPOCH + OFFSET_1900_1970 ||
549 be32toh(ntpmsg.trans_time.sec) < TIME_EPOCH + OFFSET_1900_1970) {
550 log_debug("Invalid reply, returned times before epoch. Ignoring.");
551 return manager_connect(m);
552 }
553
554 if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC ||
555 ntpmsg.stratum == 0 || ntpmsg.stratum >= 16) {
556 log_debug("Server is not synchronized. Disconnecting.");
557 return manager_connect(m);
558 }
559
560 if (!IN_SET(NTP_FIELD_VERSION(ntpmsg.field), 3, 4)) {
561 log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
562 return manager_connect(m);
563 }
564
565 if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
566 log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
567 return manager_connect(m);
568 }
569
570 root_distance = ntp_ts_short_to_d(&ntpmsg.root_delay) / 2 + ntp_ts_short_to_d(&ntpmsg.root_dispersion);
571 if (root_distance > (double) m->max_root_distance_usec / (double) USEC_PER_SEC) {
572 log_debug("Server has too large root distance. Disconnecting.");
573 return manager_connect(m);
574 }
575
576 /* valid packet */
577 m->pending = false;
578 m->retry_interval = 0;
579
580 /* Stop listening */
581 manager_listen_stop(m);
582
583 /* announce leap seconds */
584 if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
585 leap_sec = 1;
586 else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
587 leap_sec = -1;
588 else
589 leap_sec = 0;
590
591 /*
592 * "Timestamp Name ID When Generated
593 * ------------------------------------------------------------
594 * Originate Timestamp T1 time request sent by client
595 * Receive Timestamp T2 time request received by server
596 * Transmit Timestamp T3 time reply sent by server
597 * Destination Timestamp T4 time reply received by client
598 *
599 * The round-trip delay, d, and system clock offset, t, are defined as:
600 * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
601 */
602 origin = ts_to_d(&m->trans_time) + OFFSET_1900_1970;
603 receive = ntp_ts_to_d(&ntpmsg.recv_time);
604 trans = ntp_ts_to_d(&ntpmsg.trans_time);
605 dest = ts_to_d(recv_time) + OFFSET_1900_1970;
606
607 offset = ((receive - origin) + (trans - dest)) / 2;
608 delay = (dest - origin) - (trans - receive);
609
610 spike = manager_sample_spike_detection(m, offset, delay);
611
612 manager_adjust_poll(m, offset, spike);
613
614 log_debug("NTP response:\n"
615 " leap : %u\n"
616 " version : %u\n"
617 " mode : %u\n"
618 " stratum : %u\n"
619 " precision : %.6f sec (%d)\n"
620 " root distance: %.6f sec\n"
621 " reference : %.4s\n"
622 " origin : %.3f\n"
623 " receive : %.3f\n"
624 " transmit : %.3f\n"
625 " dest : %.3f\n"
626 " offset : %+.3f sec\n"
627 " delay : %+.3f sec\n"
628 " packet count : %"PRIu64"\n"
629 " jitter : %.3f%s\n"
630 " poll interval: " USEC_FMT "\n",
631 NTP_FIELD_LEAP(ntpmsg.field),
632 NTP_FIELD_VERSION(ntpmsg.field),
633 NTP_FIELD_MODE(ntpmsg.field),
634 ntpmsg.stratum,
635 exp2(ntpmsg.precision), ntpmsg.precision,
636 root_distance,
637 ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
638 origin - OFFSET_1900_1970,
639 receive - OFFSET_1900_1970,
640 trans - OFFSET_1900_1970,
641 dest - OFFSET_1900_1970,
642 offset, delay,
643 m->packet_count,
644 m->samples_jitter, spike ? " spike" : "",
645 m->poll_interval_usec / USEC_PER_SEC);
646
647 if (!spike) {
648 m->sync = true;
649 r = manager_adjust_clock(m, offset, leap_sec);
650 if (r < 0)
651 log_error_errno(r, "Failed to call clock_adjtime(): %m");
652 }
653
654 log_debug("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+ippm%s",
655 m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_ppm,
656 spike ? " (ignored)" : "");
657
658 if (!m->good) {
659 _cleanup_free_ char *pretty = NULL;
660
661 m->good = true;
662
663 server_address_pretty(m->current_server_address, &pretty);
664 log_info("Synchronized to time server %s (%s).", strna(pretty), m->current_server_name->string);
665 sd_notifyf(false, "STATUS=Synchronized to time server %s (%s).", strna(pretty), m->current_server_name->string);
666 }
667
668 r = manager_arm_timer(m, m->poll_interval_usec);
669 if (r < 0)
670 return log_error_errno(r, "Failed to rearm timer: %m");
671
672 return 0;
673 }
674
675 static int manager_listen_setup(Manager *m) {
676 union sockaddr_union addr = {};
677 static const int tos = IPTOS_LOWDELAY;
678 static const int on = 1;
679 int r;
680
681 assert(m);
682
683 if (m->server_socket >= 0)
684 return 0;
685
686 assert(!m->event_receive);
687 assert(m->current_server_address);
688
689 addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
690
691 m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
692 if (m->server_socket < 0)
693 return -errno;
694
695 r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
696 if (r < 0)
697 return -errno;
698
699 r = setsockopt(m->server_socket, SOL_SOCKET, SO_TIMESTAMPNS, &on, sizeof(on));
700 if (r < 0)
701 return -errno;
702
703 (void) setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
704
705 return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
706 }
707
708 static void manager_listen_stop(Manager *m) {
709 assert(m);
710
711 m->event_receive = sd_event_source_unref(m->event_receive);
712 m->server_socket = safe_close(m->server_socket);
713 }
714
715 static int manager_begin(Manager *m) {
716 _cleanup_free_ char *pretty = NULL;
717 int r;
718
719 assert(m);
720 assert_return(m->current_server_name, -EHOSTUNREACH);
721 assert_return(m->current_server_address, -EHOSTUNREACH);
722
723 m->good = false;
724 m->missed_replies = NTP_MAX_MISSED_REPLIES;
725 if (m->poll_interval_usec == 0)
726 m->poll_interval_usec = m->poll_interval_min_usec;
727
728 server_address_pretty(m->current_server_address, &pretty);
729 log_debug("Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
730 sd_notifyf(false, "STATUS=Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
731
732 r = manager_clock_watch_setup(m);
733 if (r < 0)
734 return r;
735
736 return manager_send_request(m);
737 }
738
739 void manager_set_server_name(Manager *m, ServerName *n) {
740 assert(m);
741
742 if (m->current_server_name == n)
743 return;
744
745 m->current_server_name = n;
746 m->current_server_address = NULL;
747
748 manager_disconnect(m);
749
750 if (n)
751 log_debug("Selected server %s.", n->string);
752 }
753
754 void manager_set_server_address(Manager *m, ServerAddress *a) {
755 assert(m);
756
757 if (m->current_server_address == a)
758 return;
759
760 m->current_server_address = a;
761 /* If a is NULL, we are just clearing the address, without
762 * changing the name. Keep the existing name in that case. */
763 if (a)
764 m->current_server_name = a->name;
765
766 manager_disconnect(m);
767
768 if (a) {
769 _cleanup_free_ char *pretty = NULL;
770 server_address_pretty(a, &pretty);
771 log_debug("Selected address %s of server %s.", strna(pretty), a->name->string);
772 }
773 }
774
775 static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) {
776 Manager *m = userdata;
777 int r;
778
779 assert(q);
780 assert(m);
781 assert(m->current_server_name);
782
783 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
784
785 if (ret != 0) {
786 log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
787
788 /* Try next host */
789 return manager_connect(m);
790 }
791
792 for (; ai; ai = ai->ai_next) {
793 _cleanup_free_ char *pretty = NULL;
794 ServerAddress *a;
795
796 assert(ai->ai_addr);
797 assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
798
799 if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
800 log_warning("Unsuitable address protocol for %s", m->current_server_name->string);
801 continue;
802 }
803
804 r = server_address_new(m->current_server_name, &a, (const union sockaddr_union*) ai->ai_addr, ai->ai_addrlen);
805 if (r < 0)
806 return log_error_errno(r, "Failed to add server address: %m");
807
808 server_address_pretty(a, &pretty);
809 log_debug("Resolved address %s for %s.", pretty, m->current_server_name->string);
810 }
811
812 if (!m->current_server_name->addresses) {
813 log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
814
815 /* Try next host */
816 return manager_connect(m);
817 }
818
819 manager_set_server_address(m, m->current_server_name->addresses);
820
821 return manager_begin(m);
822 }
823
824 static int manager_retry_connect(sd_event_source *source, usec_t usec, void *userdata) {
825 Manager *m = userdata;
826
827 assert(m);
828
829 return manager_connect(m);
830 }
831
832 int manager_connect(Manager *m) {
833 int r;
834
835 assert(m);
836
837 manager_disconnect(m);
838
839 m->event_retry = sd_event_source_unref(m->event_retry);
840 if (!ratelimit_test(&m->ratelimit)) {
841 log_debug("Slowing down attempts to contact servers.");
842
843 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);
844 if (r < 0)
845 return log_error_errno(r, "Failed to create retry timer: %m");
846
847 return 0;
848 }
849
850 /* If we already are operating on some address, switch to the
851 * next one. */
852 if (m->current_server_address && m->current_server_address->addresses_next)
853 manager_set_server_address(m, m->current_server_address->addresses_next);
854 else {
855 struct addrinfo hints = {
856 .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
857 .ai_socktype = SOCK_DGRAM,
858 };
859
860 /* Hmm, we are through all addresses, let's look for the next host instead */
861 if (m->current_server_name && m->current_server_name->names_next)
862 manager_set_server_name(m, m->current_server_name->names_next);
863 else {
864 ServerName *f;
865 bool restart = true;
866
867 /* Our current server name list is exhausted,
868 * let's find the next one to iterate. First
869 * we try the system list, then the link list.
870 * After having processed the link list we
871 * jump back to the system list. However, if
872 * both lists are empty, we change to the
873 * fallback list. */
874 if (!m->current_server_name || m->current_server_name->type == SERVER_LINK) {
875 f = m->system_servers;
876 if (!f)
877 f = m->link_servers;
878 } else {
879 f = m->link_servers;
880 if (!f)
881 f = m->system_servers;
882 else
883 restart = false;
884 }
885
886 if (!f)
887 f = m->fallback_servers;
888
889 if (!f) {
890 manager_set_server_name(m, NULL);
891 log_debug("No server found.");
892 return 0;
893 }
894
895 if (restart && !m->exhausted_servers && m->poll_interval_usec) {
896 log_debug("Waiting after exhausting servers.");
897 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);
898 if (r < 0)
899 return log_error_errno(r, "Failed to create retry timer: %m");
900
901 m->exhausted_servers = true;
902
903 /* Increase the polling interval */
904 if (m->poll_interval_usec < m->poll_interval_max_usec)
905 m->poll_interval_usec *= 2;
906
907 return 0;
908 }
909
910 m->exhausted_servers = false;
911
912 manager_set_server_name(m, f);
913 }
914
915 /* Tell the resolver to reread /etc/resolv.conf, in
916 * case it changed. */
917 res_init();
918
919 /* Flush out any previously resolved addresses */
920 server_name_flush_addresses(m->current_server_name);
921
922 log_debug("Resolving %s...", m->current_server_name->string);
923
924 r = sd_resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, m);
925 if (r < 0)
926 return log_error_errno(r, "Failed to create resolver: %m");
927
928 return 1;
929 }
930
931 r = manager_begin(m);
932 if (r < 0)
933 return r;
934
935 return 1;
936 }
937
938 void manager_disconnect(Manager *m) {
939 assert(m);
940
941 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
942
943 m->event_timer = sd_event_source_unref(m->event_timer);
944
945 manager_listen_stop(m);
946
947 m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
948 m->clock_watch_fd = safe_close(m->clock_watch_fd);
949
950 m->event_timeout = sd_event_source_unref(m->event_timeout);
951
952 sd_notifyf(false, "STATUS=Idle.");
953 }
954
955 void manager_flush_server_names(Manager *m, ServerType t) {
956 assert(m);
957
958 if (t == SERVER_SYSTEM)
959 while (m->system_servers)
960 server_name_free(m->system_servers);
961
962 if (t == SERVER_LINK)
963 while (m->link_servers)
964 server_name_free(m->link_servers);
965
966 if (t == SERVER_FALLBACK)
967 while (m->fallback_servers)
968 server_name_free(m->fallback_servers);
969 }
970
971 void manager_free(Manager *m) {
972 if (!m)
973 return;
974
975 manager_disconnect(m);
976 manager_flush_server_names(m, SERVER_SYSTEM);
977 manager_flush_server_names(m, SERVER_LINK);
978 manager_flush_server_names(m, SERVER_FALLBACK);
979
980 sd_event_source_unref(m->event_retry);
981
982 sd_event_source_unref(m->network_event_source);
983 sd_network_monitor_unref(m->network_monitor);
984
985 sd_resolve_unref(m->resolve);
986 sd_event_unref(m->event);
987
988 free(m);
989 }
990
991 static int manager_network_read_link_servers(Manager *m) {
992 _cleanup_strv_free_ char **ntp = NULL;
993 ServerName *n, *nx;
994 char **i;
995 bool changed = false;
996 int r;
997
998 assert(m);
999
1000 r = sd_network_get_ntp(&ntp);
1001 if (r < 0)
1002 goto clear;
1003
1004 LIST_FOREACH(names, n, m->link_servers)
1005 n->marked = true;
1006
1007 STRV_FOREACH(i, ntp) {
1008 bool found = false;
1009
1010 LIST_FOREACH(names, n, m->link_servers)
1011 if (streq(n->string, *i)) {
1012 n->marked = false;
1013 found = true;
1014 break;
1015 }
1016
1017 if (!found) {
1018 r = server_name_new(m, NULL, SERVER_LINK, *i);
1019 if (r < 0)
1020 goto clear;
1021
1022 changed = true;
1023 }
1024 }
1025
1026 LIST_FOREACH_SAFE(names, n, nx, m->link_servers)
1027 if (n->marked) {
1028 server_name_free(n);
1029 changed = true;
1030 }
1031
1032 return changed;
1033
1034 clear:
1035 manager_flush_server_names(m, SERVER_LINK);
1036 return r;
1037 }
1038
1039 static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
1040 Manager *m = userdata;
1041 bool changed, connected, online;
1042 int r;
1043
1044 assert(m);
1045
1046 sd_network_monitor_flush(m->network_monitor);
1047
1048 changed = !!manager_network_read_link_servers(m);
1049
1050 /* check if the machine is online */
1051 online = network_is_online();
1052
1053 /* check if the client is currently connected */
1054 connected = m->server_socket >= 0 || m->resolve_query || m->exhausted_servers;
1055
1056 if (connected && !online) {
1057 log_info("No network connectivity, watching for changes.");
1058 manager_disconnect(m);
1059
1060 } else if (!connected && online && changed) {
1061 log_info("Network configuration changed, trying to establish connection.");
1062
1063 if (m->current_server_address)
1064 r = manager_begin(m);
1065 else
1066 r = manager_connect(m);
1067 if (r < 0)
1068 return r;
1069 }
1070
1071 return 0;
1072 }
1073
1074 static int manager_network_monitor_listen(Manager *m) {
1075 int r, fd, events;
1076
1077 assert(m);
1078
1079 r = sd_network_monitor_new(&m->network_monitor, NULL);
1080 if (r == -ENOENT) {
1081 log_info("systemd does not appear to be running, not listening for systemd-networkd events.");
1082 return 0;
1083 }
1084 if (r < 0)
1085 return r;
1086
1087 fd = sd_network_monitor_get_fd(m->network_monitor);
1088 if (fd < 0)
1089 return fd;
1090
1091 events = sd_network_monitor_get_events(m->network_monitor);
1092 if (events < 0)
1093 return events;
1094
1095 r = sd_event_add_io(m->event, &m->network_event_source, fd, events, manager_network_event_handler, m);
1096 if (r < 0)
1097 return r;
1098
1099 return 0;
1100 }
1101
1102 int manager_new(Manager **ret) {
1103 _cleanup_(manager_freep) Manager *m = NULL;
1104 int r;
1105
1106 assert(ret);
1107
1108 m = new0(Manager, 1);
1109 if (!m)
1110 return -ENOMEM;
1111
1112 m->max_root_distance_usec = NTP_MAX_ROOT_DISTANCE;
1113 m->poll_interval_min_usec = NTP_POLL_INTERVAL_MIN_USEC;
1114 m->poll_interval_max_usec = NTP_POLL_INTERVAL_MAX_USEC;
1115
1116 m->server_socket = m->clock_watch_fd = -1;
1117
1118 RATELIMIT_INIT(m->ratelimit, RATELIMIT_INTERVAL_USEC, RATELIMIT_BURST);
1119
1120 r = sd_event_default(&m->event);
1121 if (r < 0)
1122 return r;
1123
1124 sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
1125 sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
1126
1127 sd_event_set_watchdog(m->event, true);
1128
1129 r = sd_resolve_default(&m->resolve);
1130 if (r < 0)
1131 return r;
1132
1133 r = sd_resolve_attach_event(m->resolve, m->event, 0);
1134 if (r < 0)
1135 return r;
1136
1137 r = manager_network_monitor_listen(m);
1138 if (r < 0)
1139 return r;
1140
1141 manager_network_read_link_servers(m);
1142
1143 *ret = TAKE_PTR(m);
1144
1145 return 0;
1146 }
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