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[thirdparty/systemd.git] / src / timesync / timesyncd-manager.c
1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3 #include <errno.h>
4 #include <math.h>
5 #include <netinet/in.h>
6 #include <netinet/ip.h>
7 #include <resolv.h>
8 #include <stdlib.h>
9 #include <sys/timerfd.h>
10 #include <sys/timex.h>
11 #include <sys/types.h>
12
13 #include "sd-daemon.h"
14 #include "sd-messages.h"
15
16 #include "alloc-util.h"
17 #include "bus-polkit.h"
18 #include "common-signal.h"
19 #include "dns-domain.h"
20 #include "event-util.h"
21 #include "fd-util.h"
22 #include "format-util.h"
23 #include "fs-util.h"
24 #include "list.h"
25 #include "log.h"
26 #include "logarithm.h"
27 #include "network-util.h"
28 #include "ratelimit.h"
29 #include "resolve-private.h"
30 #include "random-util.h"
31 #include "socket-util.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 "user-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 /* Default of maximum acceptable root distance in microseconds. */
54 #define NTP_ROOT_DISTANCE_MAX_USEC (5 * USEC_PER_SEC)
55
56 /* Maximum number of missed replies before selecting another source. */
57 #define NTP_MAX_MISSED_REPLIES 2
58
59 #define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
60 #define RATELIMIT_BURST 10
61
62 #define TIMEOUT_USEC (10*USEC_PER_SEC)
63
64 static int manager_arm_timer(Manager *m, usec_t next);
65 static int manager_clock_watch_setup(Manager *m);
66 static int manager_listen_setup(Manager *m);
67 static void manager_listen_stop(Manager *m);
68 static int manager_save_time_and_rearm(Manager *m, usec_t t);
69
70 static double ntp_ts_short_to_d(const struct ntp_ts_short *ts) {
71 return be16toh(ts->sec) + (be16toh(ts->frac) / 65536.0);
72 }
73
74 static double ntp_ts_to_d(const struct ntp_ts *ts) {
75 return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
76 }
77
78 static double ts_to_d(const struct timespec *ts) {
79 return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
80 }
81
82 static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
83 _cleanup_free_ char *pretty = NULL;
84 Manager *m = ASSERT_PTR(userdata);
85
86 assert(m->current_server_name);
87 assert(m->current_server_address);
88
89 server_address_pretty(m->current_server_address, &pretty);
90 log_info("Timed out waiting for reply from %s (%s).", strna(pretty), m->current_server_name->string);
91
92 return manager_connect(m);
93 }
94
95 static int manager_send_request(Manager *m) {
96 _cleanup_free_ char *pretty = NULL;
97 struct ntp_msg ntpmsg = {
98 /*
99 * "The client initializes the NTP message header, sends the request
100 * to the server, and strips the time of day from the Transmit
101 * Timestamp field of the reply. For this purpose, all the NTP
102 * header fields are set to 0, except the Mode, VN, and optional
103 * Transmit Timestamp fields."
104 */
105 .field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
106 };
107 ssize_t len;
108 int r;
109
110 assert(m);
111 assert(m->current_server_name);
112 assert(m->current_server_address);
113
114 m->event_timeout = sd_event_source_unref(m->event_timeout);
115
116 r = manager_listen_setup(m);
117 if (r < 0) {
118 log_warning_errno(r, "Failed to set up connection socket: %m");
119 return manager_connect(m);
120 }
121
122 /*
123 * Generate a random number as transmit timestamp, to ensure we get
124 * a full 64 bits of entropy to make it hard for off-path attackers
125 * to inject random time to us.
126 */
127 random_bytes(&m->request_nonce, sizeof(m->request_nonce));
128 ntpmsg.trans_time = m->request_nonce;
129
130 server_address_pretty(m->current_server_address, &pretty);
131
132 /*
133 * Record the transmit timestamp. This should be as close as possible to
134 * the send-to to ensure the timestamp is reasonably accurate
135 */
136 assert_se(clock_gettime(CLOCK_BOOTTIME, &m->trans_time_mon) >= 0);
137 assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
138
139 len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
140 if (len == sizeof(ntpmsg)) {
141 m->pending = true;
142 log_debug("Sent NTP request to %s (%s).", strna(pretty), m->current_server_name->string);
143 } else {
144 log_debug_errno(errno, "Sending NTP request to %s (%s) failed: %m", strna(pretty), m->current_server_name->string);
145 return manager_connect(m);
146 }
147
148 /* re-arm timer with increasing timeout, in case the packets never arrive back */
149 if (m->retry_interval == 0)
150 m->retry_interval = NTP_RETRY_INTERVAL_MIN_USEC;
151 else
152 m->retry_interval = MIN(m->retry_interval * 4/3, NTP_RETRY_INTERVAL_MAX_USEC);
153
154 r = manager_arm_timer(m, m->retry_interval);
155 if (r < 0)
156 return log_error_errno(r, "Failed to rearm timer: %m");
157
158 m->missed_replies++;
159 if (m->missed_replies > NTP_MAX_MISSED_REPLIES) {
160 r = sd_event_add_time(
161 m->event,
162 &m->event_timeout,
163 CLOCK_BOOTTIME,
164 now(CLOCK_BOOTTIME) + TIMEOUT_USEC, 0,
165 manager_timeout, m);
166 if (r < 0)
167 return log_error_errno(r, "Failed to arm timeout timer: %m");
168 }
169
170 return 0;
171 }
172
173 static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
174 Manager *m = ASSERT_PTR(userdata);
175
176 return manager_send_request(m);
177 }
178
179 static int manager_arm_timer(Manager *m, usec_t next) {
180 int r;
181
182 assert(m);
183
184 if (next == 0) {
185 m->event_timer = sd_event_source_unref(m->event_timer);
186 return 0;
187 }
188
189 if (m->event_timer) {
190 r = sd_event_source_set_time_relative(m->event_timer, next);
191 if (r < 0)
192 return r;
193
194 return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
195 }
196
197 return sd_event_add_time_relative(
198 m->event,
199 &m->event_timer,
200 CLOCK_BOOTTIME,
201 next, 0,
202 manager_timer, m);
203 }
204
205 static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
206 Manager *m = ASSERT_PTR(userdata);
207
208 /* rearm timer */
209 manager_clock_watch_setup(m);
210
211 /* skip our own jumps */
212 if (m->jumped) {
213 m->jumped = false;
214 return 0;
215 }
216
217 /* resync */
218 log_debug("System time changed. Resyncing.");
219 m->poll_resync = true;
220
221 return manager_send_request(m);
222 }
223
224 /* wake up when the system time changes underneath us */
225 static int manager_clock_watch_setup(Manager *m) {
226 int r;
227
228 assert(m);
229
230 m->event_clock_watch = sd_event_source_disable_unref(m->event_clock_watch);
231
232 r = event_add_time_change(m->event, &m->event_clock_watch, manager_clock_watch, m);
233 if (r < 0)
234 return log_error_errno(r, "Failed to create clock watch event source: %m");
235
236 return 0;
237 }
238
239 static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
240 struct timex tmx;
241
242 assert(m);
243
244 /* For small deltas, tell the kernel to gradually adjust the system clock to the NTP time, larger
245 * deltas are just directly set. */
246 if (fabs(offset) < NTP_MAX_ADJUST) {
247 tmx = (struct timex) {
248 .modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR,
249 .status = STA_PLL,
250 .offset = offset * NSEC_PER_SEC,
251 .constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4,
252 };
253
254 log_debug(" adjust (slew): %+.3f sec", offset);
255 } else {
256 tmx = (struct timex) {
257 .modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET | ADJ_MAXERROR | ADJ_ESTERROR,
258
259 /* ADJ_NANO uses nanoseconds in the microseconds field */
260 .time.tv_sec = (long)offset,
261 .time.tv_usec = (offset - (double) (long) offset) * NSEC_PER_SEC,
262 };
263
264 /* the kernel expects -0.3s as {-1, 7000.000.000} */
265 if (tmx.time.tv_usec < 0) {
266 tmx.time.tv_sec -= 1;
267 tmx.time.tv_usec += NSEC_PER_SEC;
268 }
269
270 m->jumped = true;
271 log_debug(" adjust (jump): %+.3f sec", offset);
272 }
273
274 /* An unset STA_UNSYNC will enable the kernel's 11-minute mode, which syncs the system time
275 * periodically to the RTC.
276 *
277 * In case the RTC runs in local time, never touch the RTC, we have no way to properly handle
278 * daylight saving changes and mobile devices moving between time zones. */
279 if (m->rtc_local_time)
280 tmx.status |= STA_UNSYNC;
281
282 switch (leap_sec) {
283 case 1:
284 tmx.status |= STA_INS;
285 break;
286 case -1:
287 tmx.status |= STA_DEL;
288 break;
289 }
290
291 if (clock_adjtime(CLOCK_REALTIME, &tmx) < 0)
292 return -errno;
293
294 m->drift_freq = tmx.freq;
295
296 log_debug(" status : %04i %s\n"
297 " time now : %"PRI_TIME".%03"PRI_USEC"\n"
298 " constant : %"PRI_TIMEX"\n"
299 " offset : %+.3f sec\n"
300 " freq offset : %+"PRI_TIMEX" (%+"PRI_TIMEX" ppm)\n",
301 tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
302 tmx.time.tv_sec, tmx.time.tv_usec / NSEC_PER_MSEC,
303 tmx.constant,
304 (double)tmx.offset / NSEC_PER_SEC,
305 tmx.freq, tmx.freq / 65536);
306
307 return 0;
308 }
309
310 static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
311 unsigned i, idx_cur, idx_new, idx_min;
312 double jitter;
313 double j;
314
315 assert(m);
316
317 m->packet_count++;
318
319 /* ignore initial sample */
320 if (m->packet_count == 1)
321 return false;
322
323 /* store the current data in our samples array */
324 idx_cur = m->samples_idx;
325 idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
326 m->samples_idx = idx_new;
327 m->samples[idx_new].offset = offset;
328 m->samples[idx_new].delay = delay;
329
330 /* calculate new jitter value from the RMS differences relative to the lowest delay sample */
331 jitter = m->samples_jitter;
332 for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
333 if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
334 idx_min = i;
335
336 j = 0;
337 for (i = 0; i < ELEMENTSOF(m->samples); i++)
338 j += pow(m->samples[i].offset - m->samples[idx_min].offset, 2);
339 m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
340
341 /* ignore samples when resyncing */
342 if (m->poll_resync)
343 return false;
344
345 /* always accept offset if we are farther off than the round-trip delay */
346 if (fabs(offset) > delay)
347 return false;
348
349 /* we need a few samples before looking at them */
350 if (m->packet_count < 4)
351 return false;
352
353 /* do not accept anything worse than the maximum possible error of the best sample */
354 if (fabs(offset) > m->samples[idx_min].delay)
355 return true;
356
357 /* compare the difference between the current offset to the previous offset and jitter */
358 return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
359 }
360
361 static void manager_adjust_poll(Manager *m, double offset, bool spike) {
362 assert(m);
363
364 if (m->poll_resync) {
365 m->poll_interval_usec = m->poll_interval_min_usec;
366 m->poll_resync = false;
367 return;
368 }
369
370 /* set to minimal poll interval */
371 if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
372 m->poll_interval_usec = m->poll_interval_min_usec;
373 return;
374 }
375
376 /* increase polling interval */
377 if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
378 if (m->poll_interval_usec < m->poll_interval_max_usec)
379 m->poll_interval_usec *= 2;
380 return;
381 }
382
383 /* decrease polling interval */
384 if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
385 if (m->poll_interval_usec > m->poll_interval_min_usec)
386 m->poll_interval_usec /= 2;
387 return;
388 }
389 }
390
391 static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
392 Manager *m = ASSERT_PTR(userdata);
393 struct ntp_msg ntpmsg;
394
395 struct iovec iov = {
396 .iov_base = &ntpmsg,
397 .iov_len = sizeof(ntpmsg),
398 };
399 /* This needs to be initialized with zero. See #20741. */
400 CMSG_BUFFER_TYPE(CMSG_SPACE_TIMESPEC) control = {};
401 union sockaddr_union server_addr;
402 struct msghdr msghdr = {
403 .msg_iov = &iov,
404 .msg_iovlen = 1,
405 .msg_control = &control,
406 .msg_controllen = sizeof(control),
407 .msg_name = &server_addr,
408 .msg_namelen = sizeof(server_addr),
409 };
410 struct timespec *recv_time;
411 triple_timestamp dts;
412 ssize_t len;
413 double origin, receive, trans, dest, delay, offset, root_distance;
414 bool spike;
415 int leap_sec, r;
416
417 assert(source);
418
419 if (revents & (EPOLLHUP|EPOLLERR)) {
420 log_warning("Server connection returned error.");
421 return manager_connect(m);
422 }
423
424 len = recvmsg_safe(fd, &msghdr, MSG_DONTWAIT);
425 if (len == -EAGAIN)
426 return 0;
427 if (len < 0) {
428 log_warning_errno(len, "Error receiving message, disconnecting: %m");
429 return manager_connect(m);
430 }
431
432 /* Too short or too long packet? */
433 if (iov.iov_len < sizeof(struct ntp_msg) || (msghdr.msg_flags & MSG_TRUNC)) {
434 log_warning("Invalid response from server. Disconnecting.");
435 return manager_connect(m);
436 }
437
438 if (!m->current_server_name ||
439 !m->current_server_address ||
440 !sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
441 log_debug("Response from unknown server.");
442 return 0;
443 }
444
445 recv_time = CMSG_FIND_AND_COPY_DATA(&msghdr, SOL_SOCKET, SCM_TIMESTAMPNS, struct timespec);
446 if (!recv_time)
447 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Packet timestamp missing.");
448
449 if (!m->pending) {
450 log_debug("Unexpected reply. Ignoring.");
451 return 0;
452 }
453
454 m->missed_replies = 0;
455
456 /* check the transmit request nonce was properly returned in the origin_time field */
457 if (ntpmsg.origin_time.sec != m->request_nonce.sec || ntpmsg.origin_time.frac != m->request_nonce.frac) {
458 log_debug("Invalid reply; not our transmit time. Ignoring.");
459 return 0;
460 }
461
462 m->event_timeout = sd_event_source_unref(m->event_timeout);
463
464 if (be32toh(ntpmsg.recv_time.sec) < TIME_EPOCH + OFFSET_1900_1970 ||
465 be32toh(ntpmsg.trans_time.sec) < TIME_EPOCH + OFFSET_1900_1970) {
466 log_debug("Invalid reply, returned times before epoch. Ignoring.");
467 return manager_connect(m);
468 }
469
470 if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC ||
471 ntpmsg.stratum == 0 || ntpmsg.stratum >= 16) {
472 log_debug("Server is not synchronized. Disconnecting.");
473 return manager_connect(m);
474 }
475
476 if (!IN_SET(NTP_FIELD_VERSION(ntpmsg.field), 3, 4)) {
477 log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
478 return manager_connect(m);
479 }
480
481 if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
482 log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
483 return manager_connect(m);
484 }
485
486 root_distance = ntp_ts_short_to_d(&ntpmsg.root_delay) / 2 + ntp_ts_short_to_d(&ntpmsg.root_dispersion);
487 if (root_distance > (double) m->root_distance_max_usec / (double) USEC_PER_SEC) {
488 log_info("Server has too large root distance. Disconnecting.");
489 return manager_connect(m);
490 }
491
492 /* valid packet */
493 m->pending = false;
494 m->retry_interval = 0;
495
496 /* Stop listening */
497 manager_listen_stop(m);
498
499 /* announce leap seconds */
500 if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
501 leap_sec = 1;
502 else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
503 leap_sec = -1;
504 else
505 leap_sec = 0;
506
507 /*
508 * "Timestamp Name ID When Generated
509 * ------------------------------------------------------------
510 * Originate Timestamp T1 time request sent by client
511 * Receive Timestamp T2 time request received by server
512 * Transmit Timestamp T3 time reply sent by server
513 * Destination Timestamp T4 time reply received by client
514 *
515 * The round-trip delay, d, and system clock offset, t, are defined as:
516 * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
517 */
518 origin = ts_to_d(&m->trans_time) + OFFSET_1900_1970;
519 receive = ntp_ts_to_d(&ntpmsg.recv_time);
520 trans = ntp_ts_to_d(&ntpmsg.trans_time);
521 dest = ts_to_d(recv_time) + OFFSET_1900_1970;
522
523 offset = ((receive - origin) + (trans - dest)) / 2;
524 delay = (dest - origin) - (trans - receive);
525
526 spike = manager_sample_spike_detection(m, offset, delay);
527
528 manager_adjust_poll(m, offset, spike);
529
530 log_debug("NTP response:\n"
531 " leap : %i\n"
532 " version : %i\n"
533 " mode : %i\n"
534 " stratum : %u\n"
535 " precision : %.6f sec (%i)\n"
536 " root distance: %.6f sec\n"
537 " reference : %.4s\n"
538 " origin : %.3f\n"
539 " receive : %.3f\n"
540 " transmit : %.3f\n"
541 " dest : %.3f\n"
542 " offset : %+.3f sec\n"
543 " delay : %+.3f sec\n"
544 " packet count : %"PRIu64"\n"
545 " jitter : %.3f%s\n"
546 " poll interval: " USEC_FMT "\n",
547 NTP_FIELD_LEAP(ntpmsg.field),
548 NTP_FIELD_VERSION(ntpmsg.field),
549 NTP_FIELD_MODE(ntpmsg.field),
550 ntpmsg.stratum,
551 exp2(ntpmsg.precision), ntpmsg.precision,
552 root_distance,
553 ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
554 origin - OFFSET_1900_1970,
555 receive - OFFSET_1900_1970,
556 trans - OFFSET_1900_1970,
557 dest - OFFSET_1900_1970,
558 offset, delay,
559 m->packet_count,
560 m->samples_jitter, spike ? " spike" : "",
561 m->poll_interval_usec / USEC_PER_SEC);
562
563 /* Get current monotonic/realtime clocks immediately before adjusting the latter */
564 triple_timestamp_now(&dts);
565
566 if (!spike) {
567 /* Fix up our idea of the time. */
568 dts.realtime = (usec_t) (dts.realtime + offset * USEC_PER_SEC);
569
570 r = manager_adjust_clock(m, offset, leap_sec);
571 if (r < 0)
572 log_error_errno(r, "Failed to call clock_adjtime(): %m");
573
574 (void) manager_save_time_and_rearm(m, dts.realtime);
575
576 /* If touch fails, there isn't much we can do. Maybe it'll work next time. */
577 r = touch("/run/systemd/timesync/synchronized");
578 if (r < 0)
579 log_debug_errno(r, "Failed to touch /run/systemd/timesync/synchronized, ignoring: %m");
580 }
581
582 /* Save NTP response */
583 m->ntpmsg = ntpmsg;
584 m->origin_time = m->trans_time;
585 m->dest_time = *recv_time;
586 m->spike = spike;
587
588 log_debug("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+"PRIi64"ppm%s",
589 m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_freq / 65536,
590 spike ? " (ignored)" : "");
591
592 if (sd_bus_is_ready(m->bus) > 0)
593 (void) sd_bus_emit_properties_changed(
594 m->bus,
595 "/org/freedesktop/timesync1",
596 "org.freedesktop.timesync1.Manager",
597 "NTPMessage",
598 NULL);
599
600 if (!m->talking) {
601 _cleanup_free_ char *pretty = NULL;
602
603 m->talking = true;
604
605 (void) server_address_pretty(m->current_server_address, &pretty);
606
607 log_info("Contacted time server %s (%s).", strna(pretty), m->current_server_name->string);
608 (void) sd_notifyf(false, "STATUS=Contacted time server %s (%s).", strna(pretty), m->current_server_name->string);
609 }
610
611 if (!spike && !m->synchronized) {
612 m->synchronized = true;
613
614 log_struct(LOG_INFO,
615 LOG_MESSAGE("Initial clock synchronization to %s.",
616 FORMAT_TIMESTAMP_STYLE(dts.realtime, TIMESTAMP_US)),
617 "MESSAGE_ID=" SD_MESSAGE_TIME_SYNC_STR,
618 "MONOTONIC_USEC=" USEC_FMT, dts.monotonic,
619 "REALTIME_USEC=" USEC_FMT, dts.realtime,
620 "BOOTTIME_USEC=" USEC_FMT, dts.boottime);
621 }
622
623 r = manager_arm_timer(m, m->poll_interval_usec);
624 if (r < 0)
625 return log_error_errno(r, "Failed to rearm timer: %m");
626
627 return 0;
628 }
629
630 static int manager_listen_setup(Manager *m) {
631 union sockaddr_union addr = {};
632 int r;
633
634 assert(m);
635
636 if (m->server_socket >= 0)
637 return 0;
638
639 assert(!m->event_receive);
640 assert(m->current_server_address);
641
642 addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
643
644 m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
645 if (m->server_socket < 0)
646 return -errno;
647
648 r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
649 if (r < 0)
650 return -errno;
651
652 r = setsockopt_int(m->server_socket, SOL_SOCKET, SO_TIMESTAMPNS, true);
653 if (r < 0)
654 return r;
655
656 (void) socket_set_option(m->server_socket, addr.sa.sa_family, IP_TOS, IPV6_TCLASS, IPTOS_DSCP_EF);
657
658 return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
659 }
660
661 static void manager_listen_stop(Manager *m) {
662 assert(m);
663
664 m->event_receive = sd_event_source_unref(m->event_receive);
665 m->server_socket = safe_close(m->server_socket);
666 }
667
668 static int manager_begin(Manager *m) {
669 _cleanup_free_ char *pretty = NULL;
670 int r;
671
672 assert(m);
673 assert_return(m->current_server_name, -EHOSTUNREACH);
674 assert_return(m->current_server_address, -EHOSTUNREACH);
675
676 m->talking = false;
677 m->missed_replies = NTP_MAX_MISSED_REPLIES;
678 if (m->poll_interval_usec == 0)
679 m->poll_interval_usec = m->poll_interval_min_usec;
680
681 server_address_pretty(m->current_server_address, &pretty);
682 log_debug("Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
683 (void) sd_notifyf(false, "STATUS=Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
684
685 r = manager_clock_watch_setup(m);
686 if (r < 0)
687 return r;
688
689 return manager_send_request(m);
690 }
691
692 void manager_set_server_name(Manager *m, ServerName *n) {
693 assert(m);
694
695 if (m->current_server_name == n)
696 return;
697
698 m->current_server_name = n;
699 m->current_server_address = NULL;
700
701 manager_disconnect(m);
702
703 if (n)
704 log_debug("Selected server %s.", n->string);
705 }
706
707 void manager_set_server_address(Manager *m, ServerAddress *a) {
708 assert(m);
709
710 if (m->current_server_address == a)
711 return;
712
713 m->current_server_address = a;
714 /* If a is NULL, we are just clearing the address, without
715 * changing the name. Keep the existing name in that case. */
716 if (a)
717 m->current_server_name = a->name;
718
719 manager_disconnect(m);
720
721 if (a) {
722 _cleanup_free_ char *pretty = NULL;
723 server_address_pretty(a, &pretty);
724 log_debug("Selected address %s of server %s.", strna(pretty), a->name->string);
725 }
726 }
727
728 static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, Manager *m) {
729 int r;
730
731 assert(q);
732 assert(m);
733 assert(m->current_server_name);
734
735 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
736
737 if (ret != 0) {
738 log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
739
740 /* Try next host */
741 return manager_connect(m);
742 }
743
744 for (; ai; ai = ai->ai_next) {
745 _cleanup_free_ char *pretty = NULL;
746 ServerAddress *a;
747
748 assert(ai->ai_addr);
749 assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
750
751 if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
752 log_debug("Ignoring unsuitable address protocol for %s.", m->current_server_name->string);
753 continue;
754 }
755
756 r = server_address_new(m->current_server_name, &a, (const union sockaddr_union*) ai->ai_addr, ai->ai_addrlen);
757 if (r < 0)
758 return log_error_errno(r, "Failed to add server address: %m");
759
760 server_address_pretty(a, &pretty);
761 log_debug("Resolved address %s for %s.", pretty, m->current_server_name->string);
762 }
763
764 if (!m->current_server_name->addresses) {
765 log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
766
767 /* Try next host */
768 return manager_connect(m);
769 }
770
771 manager_set_server_address(m, m->current_server_name->addresses);
772
773 return manager_begin(m);
774 }
775
776 static int manager_retry_connect(sd_event_source *source, usec_t usec, void *userdata) {
777 Manager *m = ASSERT_PTR(userdata);
778
779 return manager_connect(m);
780 }
781
782 int manager_connect(Manager *m) {
783 int r;
784
785 assert(m);
786
787 manager_disconnect(m);
788
789 m->event_retry = sd_event_source_unref(m->event_retry);
790 if (!ratelimit_below(&m->ratelimit)) {
791 log_debug("Delaying attempts to contact servers.");
792
793 r = sd_event_add_time_relative(m->event, &m->event_retry, CLOCK_BOOTTIME, m->connection_retry_usec,
794 0, manager_retry_connect, m);
795 if (r < 0)
796 return log_error_errno(r, "Failed to create retry timer: %m");
797
798 return 0;
799 }
800
801 /* If we already are operating on some address, switch to the
802 * next one. */
803 if (m->current_server_address && m->current_server_address->addresses_next)
804 manager_set_server_address(m, m->current_server_address->addresses_next);
805 else {
806 /* Hmm, we are through all addresses, let's look for the next host instead */
807 if (m->current_server_name && m->current_server_name->names_next)
808 manager_set_server_name(m, m->current_server_name->names_next);
809 else {
810 ServerName *f;
811 bool restart = true;
812
813 /* Our current server name list is exhausted,
814 * let's find the next one to iterate. First we try the runtime list, then the system list,
815 * then the link list. After having processed the link list we jump back to the system list
816 * if no runtime server list.
817 * However, if all lists are empty, we change to the fallback list. */
818 if (!m->current_server_name || m->current_server_name->type == SERVER_LINK) {
819 f = m->runtime_servers;
820 if (!f)
821 f = m->system_servers;
822 if (!f)
823 f = m->link_servers;
824 } else {
825 f = m->link_servers;
826 if (f)
827 restart = false;
828 else {
829 f = m->runtime_servers;
830 if (!f)
831 f = m->system_servers;
832 }
833 }
834
835 if (!f)
836 f = m->fallback_servers;
837
838 if (!f) {
839 manager_set_server_name(m, NULL);
840 log_debug("No server found.");
841 return 0;
842 }
843
844 if (restart && !m->exhausted_servers && m->poll_interval_usec > 0) {
845 log_debug("Waiting after exhausting servers.");
846 r = sd_event_add_time_relative(m->event, &m->event_retry, CLOCK_BOOTTIME, m->poll_interval_usec, 0, manager_retry_connect, m);
847 if (r < 0)
848 return log_error_errno(r, "Failed to create retry timer: %m");
849
850 m->exhausted_servers = true;
851
852 /* Increase the polling interval */
853 if (m->poll_interval_usec < m->poll_interval_max_usec)
854 m->poll_interval_usec *= 2;
855
856 return 0;
857 }
858
859 m->exhausted_servers = false;
860
861 manager_set_server_name(m, f);
862 }
863
864 /* Tell the resolver to reread /etc/resolv.conf, in
865 * case it changed. */
866 res_init();
867
868 /* Flush out any previously resolved addresses */
869 server_name_flush_addresses(m->current_server_name);
870
871 log_debug("Resolving %s...", m->current_server_name->string);
872
873 struct addrinfo hints = {
874 .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
875 .ai_socktype = SOCK_DGRAM,
876 .ai_family = socket_ipv6_is_supported() ? AF_UNSPEC : AF_INET,
877 };
878
879 r = resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, NULL, m);
880 if (r < 0)
881 return log_error_errno(r, "Failed to create resolver: %m");
882
883 return 1;
884 }
885
886 r = manager_begin(m);
887 if (r < 0)
888 return r;
889
890 return 1;
891 }
892
893 void manager_disconnect(Manager *m) {
894 assert(m);
895
896 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
897
898 m->event_timer = sd_event_source_unref(m->event_timer);
899
900 manager_listen_stop(m);
901
902 m->event_clock_watch = sd_event_source_disable_unref(m->event_clock_watch);
903
904 m->event_timeout = sd_event_source_unref(m->event_timeout);
905
906 (void) sd_notify(false, "STATUS=Idle.");
907 }
908
909 void manager_flush_server_names(Manager *m, ServerType t) {
910 assert(m);
911
912 if (t == SERVER_SYSTEM)
913 while (m->system_servers)
914 server_name_free(m->system_servers);
915
916 if (t == SERVER_LINK)
917 while (m->link_servers)
918 server_name_free(m->link_servers);
919
920 if (t == SERVER_FALLBACK)
921 while (m->fallback_servers)
922 server_name_free(m->fallback_servers);
923
924 if (t == SERVER_RUNTIME)
925 manager_flush_runtime_servers(m);
926 }
927
928 void manager_flush_runtime_servers(Manager *m) {
929 assert(m);
930
931 while (m->runtime_servers)
932 server_name_free(m->runtime_servers);
933 }
934
935 Manager* manager_free(Manager *m) {
936 if (!m)
937 return NULL;
938
939 manager_disconnect(m);
940 manager_flush_server_names(m, SERVER_SYSTEM);
941 manager_flush_server_names(m, SERVER_LINK);
942 manager_flush_server_names(m, SERVER_RUNTIME);
943 manager_flush_server_names(m, SERVER_FALLBACK);
944
945 sd_event_source_unref(m->event_retry);
946
947 sd_event_source_unref(m->network_event_source);
948 sd_network_monitor_unref(m->network_monitor);
949
950 sd_event_source_unref(m->event_save_time);
951
952 sd_event_source_unref(m->deferred_ntp_server_event_source);
953
954 sd_resolve_unref(m->resolve);
955 sd_event_unref(m->event);
956
957 sd_bus_flush_close_unref(m->bus);
958
959 hashmap_free(m->polkit_registry);
960
961 return mfree(m);
962 }
963
964 static int manager_network_read_link_servers(Manager *m) {
965 _cleanup_strv_free_ char **ntp = NULL;
966 bool changed = false;
967 int r;
968
969 assert(m);
970
971 r = sd_network_get_ntp(&ntp);
972 if (r < 0 && r != -ENODATA) {
973 if (r == -ENOMEM)
974 log_oom();
975 else
976 log_debug_errno(r, "Failed to get link NTP servers: %m");
977 goto clear;
978 }
979
980 LIST_FOREACH(names, n, m->link_servers)
981 n->marked = true;
982
983 STRV_FOREACH(i, ntp) {
984 bool found = false;
985
986 r = dns_name_is_valid_or_address(*i);
987 if (r < 0) {
988 log_error_errno(r, "Failed to check validity of NTP server name or address '%s': %m", *i);
989 goto clear;
990 } else if (r == 0) {
991 log_error("Invalid NTP server name or address, ignoring: %s", *i);
992 continue;
993 }
994
995 LIST_FOREACH(names, n, m->link_servers)
996 if (streq(n->string, *i)) {
997 n->marked = false;
998 found = true;
999 break;
1000 }
1001
1002 if (!found) {
1003 r = server_name_new(m, NULL, SERVER_LINK, *i);
1004 if (r < 0) {
1005 log_oom();
1006 goto clear;
1007 }
1008
1009 changed = true;
1010 }
1011 }
1012
1013 LIST_FOREACH(names, n, m->link_servers)
1014 if (n->marked) {
1015 server_name_free(n);
1016 changed = true;
1017 }
1018
1019 return changed;
1020
1021 clear:
1022 manager_flush_server_names(m, SERVER_LINK);
1023 return r;
1024 }
1025
1026 bool manager_is_connected(Manager *m) {
1027 assert(m);
1028
1029 /* Return true when the manager is sending a request, resolving a server name, or
1030 * in a poll interval. */
1031 return m->server_socket >= 0 || m->resolve_query || m->event_timer;
1032 }
1033
1034 static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
1035 Manager *m = ASSERT_PTR(userdata);
1036 bool changed, connected, online;
1037 int r;
1038
1039 sd_network_monitor_flush(m->network_monitor);
1040
1041 /* When manager_network_read_link_servers() failed, we assume that the servers are changed. */
1042 changed = manager_network_read_link_servers(m);
1043
1044 /* check if the machine is online */
1045 online = network_is_online();
1046
1047 /* check if the client is currently connected */
1048 connected = manager_is_connected(m);
1049
1050 if (connected && !online) {
1051 log_info("No network connectivity, watching for changes.");
1052 manager_disconnect(m);
1053
1054 } else if ((!connected || changed) && online) {
1055 log_info("Network configuration changed, trying to establish connection.");
1056
1057 if (m->current_server_address)
1058 r = manager_begin(m);
1059 else
1060 r = manager_connect(m);
1061 if (r < 0)
1062 return r;
1063 }
1064
1065 return 0;
1066 }
1067
1068 static int manager_network_monitor_listen(Manager *m) {
1069 int r, fd, events;
1070
1071 assert(m);
1072
1073 r = sd_network_monitor_new(&m->network_monitor, NULL);
1074 if (r == -ENOENT) {
1075 log_info("systemd does not appear to be running, not listening for systemd-networkd events.");
1076 return 0;
1077 }
1078 if (r < 0)
1079 return r;
1080
1081 fd = sd_network_monitor_get_fd(m->network_monitor);
1082 if (fd < 0)
1083 return fd;
1084
1085 events = sd_network_monitor_get_events(m->network_monitor);
1086 if (events < 0)
1087 return events;
1088
1089 r = sd_event_add_io(m->event, &m->network_event_source, fd, events, manager_network_event_handler, m);
1090 if (r < 0)
1091 return r;
1092
1093 return 0;
1094 }
1095
1096 int manager_new(Manager **ret) {
1097 _cleanup_(manager_freep) Manager *m = NULL;
1098 int r;
1099
1100 assert(ret);
1101
1102 m = new(Manager, 1);
1103 if (!m)
1104 return -ENOMEM;
1105
1106 *m = (Manager) {
1107 .root_distance_max_usec = NTP_ROOT_DISTANCE_MAX_USEC,
1108 .poll_interval_min_usec = NTP_POLL_INTERVAL_MIN_USEC,
1109 .poll_interval_max_usec = NTP_POLL_INTERVAL_MAX_USEC,
1110
1111 .connection_retry_usec = DEFAULT_CONNECTION_RETRY_USEC,
1112
1113 .server_socket = -EBADF,
1114
1115 .ratelimit = (const RateLimit) {
1116 RATELIMIT_INTERVAL_USEC,
1117 RATELIMIT_BURST
1118 },
1119
1120 .save_time_interval_usec = DEFAULT_SAVE_TIME_INTERVAL_USEC,
1121 };
1122
1123 r = sd_event_default(&m->event);
1124 if (r < 0)
1125 return r;
1126
1127 (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
1128 (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
1129 (void) sd_event_add_signal(m->event, NULL, SIGRTMIN+18, sigrtmin18_handler, NULL);
1130
1131 r = sd_event_add_memory_pressure(m->event, NULL, NULL, NULL);
1132 if (r < 0)
1133 log_debug_errno(r, "Failed allocate memory pressure event source, ignoring: %m");
1134
1135 (void) sd_event_set_watchdog(m->event, true);
1136
1137 /* Load previous synchronization state */
1138 r = access("/run/systemd/timesync/synchronized", F_OK);
1139 if (r < 0 && errno != ENOENT)
1140 log_debug_errno(errno, "Failed to determine whether /run/systemd/timesync/synchronized exists, ignoring: %m");
1141 m->synchronized = r >= 0;
1142
1143 r = sd_resolve_default(&m->resolve);
1144 if (r < 0)
1145 return r;
1146
1147 r = sd_resolve_attach_event(m->resolve, m->event, 0);
1148 if (r < 0)
1149 return r;
1150
1151 r = manager_network_monitor_listen(m);
1152 if (r < 0)
1153 return r;
1154
1155 (void) manager_network_read_link_servers(m);
1156
1157 *ret = TAKE_PTR(m);
1158
1159 return 0;
1160 }
1161
1162 static int manager_save_time_handler(sd_event_source *s, uint64_t usec, void *userdata) {
1163 Manager *m = ASSERT_PTR(userdata);
1164
1165 (void) manager_save_time_and_rearm(m, USEC_INFINITY);
1166 return 0;
1167 }
1168
1169 int manager_setup_save_time_event(Manager *m) {
1170 int r;
1171
1172 assert(m);
1173 assert(!m->event_save_time);
1174
1175 if (m->save_time_interval_usec == USEC_INFINITY)
1176 return 0;
1177
1178 /* NB: we'll accumulate scheduling latencies here, but this doesn't matter */
1179 r = sd_event_add_time_relative(
1180 m->event, &m->event_save_time,
1181 CLOCK_BOOTTIME,
1182 m->save_time_interval_usec,
1183 10 * USEC_PER_SEC,
1184 manager_save_time_handler, m);
1185 if (r < 0)
1186 return log_error_errno(r, "Failed to add save time event: %m");
1187
1188 (void) sd_event_source_set_description(m->event_save_time, "save-time");
1189
1190 return 0;
1191 }
1192
1193 static int manager_save_time_and_rearm(Manager *m, usec_t t) {
1194 int r;
1195
1196 assert(m);
1197
1198 /* Updates the timestamp file to the specified time. If 't' is USEC_INFINITY uses the current system
1199 * clock, but otherwise uses the specified timestamp. Note that whenever we acquire an NTP sync the
1200 * specified timestamp value might be more accurate than the system clock, since the latter is
1201 * subject to slow adjustments. */
1202 r = touch_file(CLOCK_FILE, false, t, UID_INVALID, GID_INVALID, MODE_INVALID);
1203 if (r < 0)
1204 log_debug_errno(r, "Failed to update " CLOCK_FILE ", ignoring: %m");
1205
1206 m->save_on_exit = true;
1207
1208 if (m->save_time_interval_usec != USEC_INFINITY) {
1209 r = sd_event_source_set_time_relative(m->event_save_time, m->save_time_interval_usec);
1210 if (r < 0)
1211 return log_error_errno(r, "Failed to rearm save time event: %m");
1212
1213 r = sd_event_source_set_enabled(m->event_save_time, SD_EVENT_ONESHOT);
1214 if (r < 0)
1215 return log_error_errno(r, "Failed to enable save time event: %m");
1216 }
1217
1218 return 0;
1219 }
1220
1221 static const char* ntp_server_property_name[_SERVER_TYPE_MAX] = {
1222 [SERVER_SYSTEM] = "SystemNTPServers",
1223 [SERVER_FALLBACK] = "FallbackNTPServers",
1224 [SERVER_LINK] = "LinkNTPServers",
1225 [SERVER_RUNTIME] = "RuntimeNTPServers",
1226 };
1227
1228 static int ntp_server_emit_changed_strv(Manager *manager, char **properties) {
1229 assert(manager);
1230 assert(properties);
1231
1232 if (sd_bus_is_ready(manager->bus) <= 0)
1233 return 0;
1234
1235 return sd_bus_emit_properties_changed_strv(
1236 manager->bus,
1237 "/org/freedesktop/timesync1",
1238 "org.freedesktop.timesync1.Manager",
1239 properties);
1240 }
1241
1242 static int on_deferred_ntp_server(sd_event_source *s, void *userdata) {
1243 int r;
1244 _cleanup_strv_free_ char **p = NULL;
1245 Manager *m = ASSERT_PTR(userdata);
1246
1247 m->deferred_ntp_server_event_source = sd_event_source_disable_unref(m->deferred_ntp_server_event_source);
1248
1249 for (int type = SERVER_SYSTEM; type < _SERVER_TYPE_MAX; type++)
1250 if (m->ntp_server_change_mask & (1U << type))
1251 if (strv_extend(&p, ntp_server_property_name[type]) < 0)
1252 log_oom();
1253
1254 m->ntp_server_change_mask = 0;
1255
1256 if (strv_isempty(p))
1257 return log_error_errno(SYNTHETIC_ERRNO(ENOMEM), "Failed to build ntp server event strv!");
1258
1259 r = ntp_server_emit_changed_strv(m, p);
1260 if (r < 0)
1261 log_warning_errno(r, "Could not emit ntp server changed properties, ignoring: %m");
1262
1263 return 0;
1264 }
1265
1266 int bus_manager_emit_ntp_server_changed(Manager *m) {
1267 int r;
1268
1269 assert(m);
1270
1271 if (m->deferred_ntp_server_event_source)
1272 return 0;
1273
1274 if (!m->event)
1275 return 0;
1276
1277 if (IN_SET(sd_event_get_state(m->event), SD_EVENT_FINISHED, SD_EVENT_EXITING))
1278 return 0;
1279
1280 r = sd_event_add_defer(m->event, &m->deferred_ntp_server_event_source, on_deferred_ntp_server, m);
1281 if (r < 0)
1282 return log_error_errno(r, "Failed to allocate ntp server event source: %m");
1283
1284 (void) sd_event_source_set_description(m->deferred_ntp_server_event_source, "deferred-ntp-server");
1285
1286 return 1;
1287 }
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