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timesyncd: don't abort packet handling if we can't save the timestamp to disk
[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
15 #include "alloc-util.h"
16 #include "dns-domain.h"
17 #include "event-util.h"
18 #include "fd-util.h"
19 #include "format-util.h"
20 #include "fs-util.h"
21 #include "list.h"
22 #include "log.h"
23 #include "network-util.h"
24 #include "ratelimit.h"
25 #include "resolve-private.h"
26 #include "socket-util.h"
27 #include "string-util.h"
28 #include "strv.h"
29 #include "time-util.h"
30 #include "timesyncd-conf.h"
31 #include "timesyncd-manager.h"
32 #include "util.h"
33
34 #ifndef ADJ_SETOFFSET
35 #define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
36 #endif
37
38 /* Expected accuracy of time synchronization; used to adjust the poll interval */
39 #define NTP_ACCURACY_SEC 0.2
40
41 /*
42 * Maximum delta in seconds which the system clock is gradually adjusted
43 * (slewed) to approach the network time. Deltas larger that this are set by
44 * letting the system time jump. The kernel's limit for adjtime is 0.5s.
45 */
46 #define NTP_MAX_ADJUST 0.4
47
48 /* Default of maximum acceptable root distance in microseconds. */
49 #define NTP_ROOT_DISTANCE_MAX_USEC (5 * USEC_PER_SEC)
50
51 /* Maximum number of missed replies before selecting another source. */
52 #define NTP_MAX_MISSED_REPLIES 2
53
54 #define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
55 #define RATELIMIT_BURST 10
56
57 #define TIMEOUT_USEC (10*USEC_PER_SEC)
58
59 static int manager_arm_timer(Manager *m, usec_t next);
60 static int manager_clock_watch_setup(Manager *m);
61 static int manager_listen_setup(Manager *m);
62 static void manager_listen_stop(Manager *m);
63 static int manager_save_time_and_rearm(Manager *m);
64
65 static double ntp_ts_short_to_d(const struct ntp_ts_short *ts) {
66 return be16toh(ts->sec) + (be16toh(ts->frac) / 65536.0);
67 }
68
69 static double ntp_ts_to_d(const struct ntp_ts *ts) {
70 return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
71 }
72
73 static double ts_to_d(const struct timespec *ts) {
74 return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
75 }
76
77 static uint32_t graceful_add_offset_1900_1970(time_t t) {
78 /* Adds OFFSET_1900_1970 to t and returns it as 32bit value. This is handles overflows
79 * gracefully in a deterministic and well-defined way by cutting off the top bits. */
80 uint64_t a = (uint64_t) t + OFFSET_1900_1970;
81 return (uint32_t) (a & UINT64_C(0xFFFFFFFF));
82 }
83
84 static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
85 _cleanup_free_ char *pretty = NULL;
86 Manager *m = userdata;
87
88 assert(m);
89 assert(m->current_server_name);
90 assert(m->current_server_address);
91
92 server_address_pretty(m->current_server_address, &pretty);
93 log_info("Timed out waiting for reply from %s (%s).", strna(pretty), m->current_server_name->string);
94
95 return manager_connect(m);
96 }
97
98 static int manager_send_request(Manager *m) {
99 _cleanup_free_ char *pretty = NULL;
100 struct ntp_msg ntpmsg = {
101 /*
102 * "The client initializes the NTP message header, sends the request
103 * to the server, and strips the time of day from the Transmit
104 * Timestamp field of the reply. For this purpose, all the NTP
105 * header fields are set to 0, except the Mode, VN, and optional
106 * Transmit Timestamp fields."
107 */
108 .field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
109 };
110 ssize_t len;
111 int r;
112
113 assert(m);
114 assert(m->current_server_name);
115 assert(m->current_server_address);
116
117 m->event_timeout = sd_event_source_unref(m->event_timeout);
118
119 r = manager_listen_setup(m);
120 if (r < 0)
121 return log_warning_errno(r, "Failed to set up connection socket: %m");
122
123 /*
124 * Set transmit timestamp, remember it; the server will send that back
125 * as the origin timestamp and we have an indication that this is the
126 * matching answer to our request.
127 *
128 * The actual value does not matter, We do not care about the correct
129 * NTP UINT_MAX fraction; we just pass the plain nanosecond value.
130 */
131 assert_se(clock_gettime(clock_boottime_or_monotonic(), &m->trans_time_mon) >= 0);
132 assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
133 ntpmsg.trans_time.sec = htobe32(graceful_add_offset_1900_1970(m->trans_time.tv_sec));
134 ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
135
136 server_address_pretty(m->current_server_address, &pretty);
137
138 len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
139 if (len == sizeof(ntpmsg)) {
140 m->pending = true;
141 log_debug("Sent NTP request to %s (%s).", strna(pretty), m->current_server_name->string);
142 } else {
143 log_debug_errno(errno, "Sending NTP request to %s (%s) failed: %m", strna(pretty), m->current_server_name->string);
144 return manager_connect(m);
145 }
146
147 /* re-arm timer with increasing timeout, in case the packets never arrive back */
148 if (m->retry_interval == 0)
149 m->retry_interval = NTP_RETRY_INTERVAL_MIN_USEC;
150 else
151 m->retry_interval = MIN(m->retry_interval * 4/3, NTP_RETRY_INTERVAL_MAX_USEC);
152
153 r = manager_arm_timer(m, m->retry_interval);
154 if (r < 0)
155 return log_error_errno(r, "Failed to rearm timer: %m");
156
157 m->missed_replies++;
158 if (m->missed_replies > NTP_MAX_MISSED_REPLIES) {
159 r = sd_event_add_time(
160 m->event,
161 &m->event_timeout,
162 clock_boottime_or_monotonic(),
163 now(clock_boottime_or_monotonic()) + TIMEOUT_USEC, 0,
164 manager_timeout, m);
165 if (r < 0)
166 return log_error_errno(r, "Failed to arm timeout timer: %m");
167 }
168
169 return 0;
170 }
171
172 static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
173 Manager *m = userdata;
174
175 assert(m);
176
177 return manager_send_request(m);
178 }
179
180 static int manager_arm_timer(Manager *m, usec_t next) {
181 int r;
182
183 assert(m);
184
185 if (next == 0) {
186 m->event_timer = sd_event_source_unref(m->event_timer);
187 return 0;
188 }
189
190 if (m->event_timer) {
191 r = sd_event_source_set_time_relative(m->event_timer, next);
192 if (r < 0)
193 return r;
194
195 return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
196 }
197
198 return sd_event_add_time_relative(
199 m->event,
200 &m->event_timer,
201 clock_boottime_or_monotonic(),
202 next, 0,
203 manager_timer, m);
204 }
205
206 static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
207 Manager *m = userdata;
208
209 assert(m);
210
211 /* rearm timer */
212 manager_clock_watch_setup(m);
213
214 /* skip our own jumps */
215 if (m->jumped) {
216 m->jumped = false;
217 return 0;
218 }
219
220 /* resync */
221 log_debug("System time changed. Resyncing.");
222 m->poll_resync = true;
223
224 return manager_send_request(m);
225 }
226
227 /* wake up when the system time changes underneath us */
228 static int manager_clock_watch_setup(Manager *m) {
229 int r;
230
231 assert(m);
232
233 m->event_clock_watch = sd_event_source_disable_unref(m->event_clock_watch);
234
235 r = event_add_time_change(m->event, &m->event_clock_watch, manager_clock_watch, m);
236 if (r < 0)
237 return log_error_errno(r, "Failed to create clock watch event source: %m");
238
239 return 0;
240 }
241
242 static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
243 struct timex tmx;
244
245 assert(m);
246
247 /* For small deltas, tell the kernel to gradually adjust the system clock to the NTP time, larger
248 * deltas are just directly set. */
249 if (fabs(offset) < NTP_MAX_ADJUST) {
250 tmx = (struct timex) {
251 .modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR,
252 .status = STA_PLL,
253 .offset = offset * NSEC_PER_SEC,
254 .constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4,
255 };
256
257 log_debug(" adjust (slew): %+.3f sec", offset);
258 } else {
259 tmx = (struct timex) {
260 .modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET | ADJ_MAXERROR | ADJ_ESTERROR,
261
262 /* ADJ_NANO uses nanoseconds in the microseconds field */
263 .time.tv_sec = (long)offset,
264 .time.tv_usec = (offset - (double) (long) offset) * NSEC_PER_SEC,
265 };
266
267 /* the kernel expects -0.3s as {-1, 7000.000.000} */
268 if (tmx.time.tv_usec < 0) {
269 tmx.time.tv_sec -= 1;
270 tmx.time.tv_usec += NSEC_PER_SEC;
271 }
272
273 m->jumped = true;
274 log_debug(" adjust (jump): %+.3f sec", offset);
275 }
276
277 /* An unset STA_UNSYNC will enable the kernel's 11-minute mode, which syncs the system time
278 * periodically to the RTC.
279 *
280 * In case the RTC runs in local time, never touch the RTC, we have no way to properly handle
281 * daylight saving changes and mobile devices moving between time zones. */
282 if (m->rtc_local_time)
283 tmx.status |= STA_UNSYNC;
284
285 switch (leap_sec) {
286 case 1:
287 tmx.status |= STA_INS;
288 break;
289 case -1:
290 tmx.status |= STA_DEL;
291 break;
292 }
293
294 if (clock_adjtime(CLOCK_REALTIME, &tmx) < 0)
295 return -errno;
296
297 m->drift_freq = tmx.freq;
298
299 log_debug(" status : %04i %s\n"
300 " time now : %"PRI_TIME".%03"PRI_USEC"\n"
301 " constant : %"PRI_TIMEX"\n"
302 " offset : %+.3f sec\n"
303 " freq offset : %+"PRI_TIMEX" (%+"PRI_TIMEX" ppm)\n",
304 tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
305 tmx.time.tv_sec, tmx.time.tv_usec / NSEC_PER_MSEC,
306 tmx.constant,
307 (double)tmx.offset / NSEC_PER_SEC,
308 tmx.freq, tmx.freq / 65536);
309
310 return 0;
311 }
312
313 static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
314 unsigned i, idx_cur, idx_new, idx_min;
315 double jitter;
316 double j;
317
318 assert(m);
319
320 m->packet_count++;
321
322 /* ignore initial sample */
323 if (m->packet_count == 1)
324 return false;
325
326 /* store the current data in our samples array */
327 idx_cur = m->samples_idx;
328 idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
329 m->samples_idx = idx_new;
330 m->samples[idx_new].offset = offset;
331 m->samples[idx_new].delay = delay;
332
333 /* calculate new jitter value from the RMS differences relative to the lowest delay sample */
334 jitter = m->samples_jitter;
335 for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
336 if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
337 idx_min = i;
338
339 j = 0;
340 for (i = 0; i < ELEMENTSOF(m->samples); i++)
341 j += pow(m->samples[i].offset - m->samples[idx_min].offset, 2);
342 m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
343
344 /* ignore samples when resyncing */
345 if (m->poll_resync)
346 return false;
347
348 /* always accept offset if we are farther off than the round-trip delay */
349 if (fabs(offset) > delay)
350 return false;
351
352 /* we need a few samples before looking at them */
353 if (m->packet_count < 4)
354 return false;
355
356 /* do not accept anything worse than the maximum possible error of the best sample */
357 if (fabs(offset) > m->samples[idx_min].delay)
358 return true;
359
360 /* compare the difference between the current offset to the previous offset and jitter */
361 return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
362 }
363
364 static void manager_adjust_poll(Manager *m, double offset, bool spike) {
365 assert(m);
366
367 if (m->poll_resync) {
368 m->poll_interval_usec = m->poll_interval_min_usec;
369 m->poll_resync = false;
370 return;
371 }
372
373 /* set to minimal poll interval */
374 if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
375 m->poll_interval_usec = m->poll_interval_min_usec;
376 return;
377 }
378
379 /* increase polling interval */
380 if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
381 if (m->poll_interval_usec < m->poll_interval_max_usec)
382 m->poll_interval_usec *= 2;
383 return;
384 }
385
386 /* decrease polling interval */
387 if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
388 if (m->poll_interval_usec > m->poll_interval_min_usec)
389 m->poll_interval_usec /= 2;
390 return;
391 }
392 }
393
394 static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
395 Manager *m = userdata;
396 struct ntp_msg ntpmsg;
397
398 struct iovec iov = {
399 .iov_base = &ntpmsg,
400 .iov_len = sizeof(ntpmsg),
401 };
402 /* This needs to be initialized with zero. See #20741. */
403 CMSG_BUFFER_TYPE(CMSG_SPACE_TIMESPEC) control = {};
404 union sockaddr_union server_addr;
405 struct msghdr msghdr = {
406 .msg_iov = &iov,
407 .msg_iovlen = 1,
408 .msg_control = &control,
409 .msg_controllen = sizeof(control),
410 .msg_name = &server_addr,
411 .msg_namelen = sizeof(server_addr),
412 };
413 struct timespec *recv_time = NULL;
414 ssize_t len;
415 double origin, receive, trans, dest, delay, offset, root_distance;
416 bool spike;
417 int leap_sec, r;
418
419 assert(source);
420 assert(m);
421
422 if (revents & (EPOLLHUP|EPOLLERR)) {
423 log_warning("Server connection returned error.");
424 return manager_connect(m);
425 }
426
427 len = recvmsg_safe(fd, &msghdr, MSG_DONTWAIT);
428 if (len == -EAGAIN)
429 return 0;
430 if (len < 0) {
431 log_warning_errno(len, "Error receiving message, disconnecting: %m");
432 return manager_connect(m);
433 }
434
435 /* Too short or too long packet? */
436 if (iov.iov_len < sizeof(struct ntp_msg) || (msghdr.msg_flags & MSG_TRUNC)) {
437 log_warning("Invalid response from server. Disconnecting.");
438 return manager_connect(m);
439 }
440
441 if (!m->current_server_name ||
442 !m->current_server_address ||
443 !sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
444 log_debug("Response from unknown server.");
445 return 0;
446 }
447
448 recv_time = CMSG_FIND_DATA(&msghdr, SOL_SOCKET, SCM_TIMESTAMPNS, struct timespec);
449 if (!recv_time)
450 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Packet timestamp missing.");
451
452 if (!m->pending) {
453 log_debug("Unexpected reply. Ignoring.");
454 return 0;
455 }
456
457 m->missed_replies = 0;
458
459 /* check our "time cookie" (we just stored nanoseconds in the fraction field) */
460 if (be32toh(ntpmsg.origin_time.sec) != graceful_add_offset_1900_1970(m->trans_time.tv_sec) ||
461 be32toh(ntpmsg.origin_time.frac) != (unsigned long) m->trans_time.tv_nsec) {
462 log_debug("Invalid reply; not our transmit time. Ignoring.");
463 return 0;
464 }
465
466 m->event_timeout = sd_event_source_unref(m->event_timeout);
467
468 if (be32toh(ntpmsg.recv_time.sec) < TIME_EPOCH + OFFSET_1900_1970 ||
469 be32toh(ntpmsg.trans_time.sec) < TIME_EPOCH + OFFSET_1900_1970) {
470 log_debug("Invalid reply, returned times before epoch. Ignoring.");
471 return manager_connect(m);
472 }
473
474 if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC ||
475 ntpmsg.stratum == 0 || ntpmsg.stratum >= 16) {
476 log_debug("Server is not synchronized. Disconnecting.");
477 return manager_connect(m);
478 }
479
480 if (!IN_SET(NTP_FIELD_VERSION(ntpmsg.field), 3, 4)) {
481 log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
482 return manager_connect(m);
483 }
484
485 if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
486 log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
487 return manager_connect(m);
488 }
489
490 root_distance = ntp_ts_short_to_d(&ntpmsg.root_delay) / 2 + ntp_ts_short_to_d(&ntpmsg.root_dispersion);
491 if (root_distance > (double) m->root_distance_max_usec / (double) USEC_PER_SEC) {
492 log_info("Server has too large root distance. Disconnecting.");
493 return manager_connect(m);
494 }
495
496 /* valid packet */
497 m->pending = false;
498 m->retry_interval = 0;
499
500 /* Stop listening */
501 manager_listen_stop(m);
502
503 /* announce leap seconds */
504 if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
505 leap_sec = 1;
506 else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
507 leap_sec = -1;
508 else
509 leap_sec = 0;
510
511 /*
512 * "Timestamp Name ID When Generated
513 * ------------------------------------------------------------
514 * Originate Timestamp T1 time request sent by client
515 * Receive Timestamp T2 time request received by server
516 * Transmit Timestamp T3 time reply sent by server
517 * Destination Timestamp T4 time reply received by client
518 *
519 * The round-trip delay, d, and system clock offset, t, are defined as:
520 * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
521 */
522 origin = ts_to_d(&m->trans_time) + OFFSET_1900_1970;
523 receive = ntp_ts_to_d(&ntpmsg.recv_time);
524 trans = ntp_ts_to_d(&ntpmsg.trans_time);
525 dest = ts_to_d(recv_time) + OFFSET_1900_1970;
526
527 offset = ((receive - origin) + (trans - dest)) / 2;
528 delay = (dest - origin) - (trans - receive);
529
530 spike = manager_sample_spike_detection(m, offset, delay);
531
532 manager_adjust_poll(m, offset, spike);
533
534 log_debug("NTP response:\n"
535 " leap : %u\n"
536 " version : %u\n"
537 " mode : %u\n"
538 " stratum : %u\n"
539 " precision : %.6f sec (%d)\n"
540 " root distance: %.6f sec\n"
541 " reference : %.4s\n"
542 " origin : %.3f\n"
543 " receive : %.3f\n"
544 " transmit : %.3f\n"
545 " dest : %.3f\n"
546 " offset : %+.3f sec\n"
547 " delay : %+.3f sec\n"
548 " packet count : %"PRIu64"\n"
549 " jitter : %.3f%s\n"
550 " poll interval: " USEC_FMT "\n",
551 NTP_FIELD_LEAP(ntpmsg.field),
552 NTP_FIELD_VERSION(ntpmsg.field),
553 NTP_FIELD_MODE(ntpmsg.field),
554 ntpmsg.stratum,
555 exp2(ntpmsg.precision), ntpmsg.precision,
556 root_distance,
557 ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
558 origin - OFFSET_1900_1970,
559 receive - OFFSET_1900_1970,
560 trans - OFFSET_1900_1970,
561 dest - OFFSET_1900_1970,
562 offset, delay,
563 m->packet_count,
564 m->samples_jitter, spike ? " spike" : "",
565 m->poll_interval_usec / USEC_PER_SEC);
566
567 if (!spike) {
568 r = manager_adjust_clock(m, offset, leap_sec);
569 if (r < 0)
570 log_error_errno(r, "Failed to call clock_adjtime(): %m");
571
572 (void) manager_save_time_and_rearm(m);
573
574 /* If touch fails, there isn't much we can do. Maybe it'll work next time. */
575 (void) touch("/run/systemd/timesync/synchronized");
576 }
577
578 /* Save NTP response */
579 m->ntpmsg = ntpmsg;
580 m->origin_time = m->trans_time;
581 m->dest_time = *recv_time;
582 m->spike = spike;
583
584 log_debug("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+"PRIi64"ppm%s",
585 m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_freq / 65536,
586 spike ? " (ignored)" : "");
587
588 if (sd_bus_is_ready(m->bus) > 0)
589 (void) sd_bus_emit_properties_changed(
590 m->bus,
591 "/org/freedesktop/timesync1",
592 "org.freedesktop.timesync1.Manager",
593 "NTPMessage",
594 NULL);
595
596 if (!m->good) {
597 _cleanup_free_ char *pretty = NULL;
598
599 m->good = true;
600
601 (void) server_address_pretty(m->current_server_address, &pretty);
602
603 /* "Initial", as further successful syncs will not be logged. */
604 log_info("Initial synchronization to time server %s (%s).", strna(pretty), m->current_server_name->string);
605 (void) sd_notifyf(false, "STATUS=Initial synchronization to time server %s (%s).", strna(pretty), m->current_server_name->string);
606 }
607
608 r = manager_arm_timer(m, m->poll_interval_usec);
609 if (r < 0)
610 return log_error_errno(r, "Failed to rearm timer: %m");
611
612 return 0;
613 }
614
615 static int manager_listen_setup(Manager *m) {
616 union sockaddr_union addr = {};
617 int r;
618
619 assert(m);
620
621 if (m->server_socket >= 0)
622 return 0;
623
624 assert(!m->event_receive);
625 assert(m->current_server_address);
626
627 addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
628
629 m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
630 if (m->server_socket < 0)
631 return -errno;
632
633 r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
634 if (r < 0)
635 return -errno;
636
637 r = setsockopt_int(m->server_socket, SOL_SOCKET, SO_TIMESTAMPNS, true);
638 if (r < 0)
639 return r;
640
641 if (addr.sa.sa_family == AF_INET)
642 (void) setsockopt_int(m->server_socket, IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY);
643
644 return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
645 }
646
647 static void manager_listen_stop(Manager *m) {
648 assert(m);
649
650 m->event_receive = sd_event_source_unref(m->event_receive);
651 m->server_socket = safe_close(m->server_socket);
652 }
653
654 static int manager_begin(Manager *m) {
655 _cleanup_free_ char *pretty = NULL;
656 int r;
657
658 assert(m);
659 assert_return(m->current_server_name, -EHOSTUNREACH);
660 assert_return(m->current_server_address, -EHOSTUNREACH);
661
662 m->good = false;
663 m->missed_replies = NTP_MAX_MISSED_REPLIES;
664 if (m->poll_interval_usec == 0)
665 m->poll_interval_usec = m->poll_interval_min_usec;
666
667 server_address_pretty(m->current_server_address, &pretty);
668 log_debug("Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
669 (void) sd_notifyf(false, "STATUS=Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
670
671 r = manager_clock_watch_setup(m);
672 if (r < 0)
673 return r;
674
675 return manager_send_request(m);
676 }
677
678 void manager_set_server_name(Manager *m, ServerName *n) {
679 assert(m);
680
681 if (m->current_server_name == n)
682 return;
683
684 m->current_server_name = n;
685 m->current_server_address = NULL;
686
687 manager_disconnect(m);
688
689 if (n)
690 log_debug("Selected server %s.", n->string);
691 }
692
693 void manager_set_server_address(Manager *m, ServerAddress *a) {
694 assert(m);
695
696 if (m->current_server_address == a)
697 return;
698
699 m->current_server_address = a;
700 /* If a is NULL, we are just clearing the address, without
701 * changing the name. Keep the existing name in that case. */
702 if (a)
703 m->current_server_name = a->name;
704
705 manager_disconnect(m);
706
707 if (a) {
708 _cleanup_free_ char *pretty = NULL;
709 server_address_pretty(a, &pretty);
710 log_debug("Selected address %s of server %s.", strna(pretty), a->name->string);
711 }
712 }
713
714 static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, Manager *m) {
715 int r;
716
717 assert(q);
718 assert(m);
719 assert(m->current_server_name);
720
721 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
722
723 if (ret != 0) {
724 log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
725
726 /* Try next host */
727 return manager_connect(m);
728 }
729
730 for (; ai; ai = ai->ai_next) {
731 _cleanup_free_ char *pretty = NULL;
732 ServerAddress *a;
733
734 assert(ai->ai_addr);
735 assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
736
737 if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
738 log_warning("Unsuitable address protocol for %s", m->current_server_name->string);
739 continue;
740 }
741
742 r = server_address_new(m->current_server_name, &a, (const union sockaddr_union*) ai->ai_addr, ai->ai_addrlen);
743 if (r < 0)
744 return log_error_errno(r, "Failed to add server address: %m");
745
746 server_address_pretty(a, &pretty);
747 log_debug("Resolved address %s for %s.", pretty, m->current_server_name->string);
748 }
749
750 if (!m->current_server_name->addresses) {
751 log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
752
753 /* Try next host */
754 return manager_connect(m);
755 }
756
757 manager_set_server_address(m, m->current_server_name->addresses);
758
759 return manager_begin(m);
760 }
761
762 static int manager_retry_connect(sd_event_source *source, usec_t usec, void *userdata) {
763 Manager *m = userdata;
764
765 assert(m);
766
767 return manager_connect(m);
768 }
769
770 int manager_connect(Manager *m) {
771 int r;
772
773 assert(m);
774
775 manager_disconnect(m);
776
777 m->event_retry = sd_event_source_unref(m->event_retry);
778 if (!ratelimit_below(&m->ratelimit)) {
779 log_debug("Delaying attempts to contact servers.");
780
781 r = sd_event_add_time_relative(m->event, &m->event_retry, clock_boottime_or_monotonic(), m->connection_retry_usec,
782 0, manager_retry_connect, m);
783 if (r < 0)
784 return log_error_errno(r, "Failed to create retry timer: %m");
785
786 return 0;
787 }
788
789 /* If we already are operating on some address, switch to the
790 * next one. */
791 if (m->current_server_address && m->current_server_address->addresses_next)
792 manager_set_server_address(m, m->current_server_address->addresses_next);
793 else {
794 static const struct addrinfo hints = {
795 .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
796 .ai_socktype = SOCK_DGRAM,
797 };
798
799 /* Hmm, we are through all addresses, let's look for the next host instead */
800 if (m->current_server_name && m->current_server_name->names_next)
801 manager_set_server_name(m, m->current_server_name->names_next);
802 else {
803 ServerName *f;
804 bool restart = true;
805
806 /* Our current server name list is exhausted,
807 * let's find the next one to iterate. First
808 * we try the system list, then the link list.
809 * After having processed the link list we
810 * jump back to the system list. However, if
811 * both lists are empty, we change to the
812 * fallback list. */
813 if (!m->current_server_name || m->current_server_name->type == SERVER_LINK) {
814 f = m->system_servers;
815 if (!f)
816 f = m->link_servers;
817 } else {
818 f = m->link_servers;
819 if (!f)
820 f = m->system_servers;
821 else
822 restart = false;
823 }
824
825 if (!f)
826 f = m->fallback_servers;
827
828 if (!f) {
829 manager_set_server_name(m, NULL);
830 log_debug("No server found.");
831 return 0;
832 }
833
834 if (restart && !m->exhausted_servers && m->poll_interval_usec) {
835 log_debug("Waiting after exhausting servers.");
836 r = sd_event_add_time_relative(m->event, &m->event_retry, clock_boottime_or_monotonic(), m->poll_interval_usec, 0, manager_retry_connect, m);
837 if (r < 0)
838 return log_error_errno(r, "Failed to create retry timer: %m");
839
840 m->exhausted_servers = true;
841
842 /* Increase the polling interval */
843 if (m->poll_interval_usec < m->poll_interval_max_usec)
844 m->poll_interval_usec *= 2;
845
846 return 0;
847 }
848
849 m->exhausted_servers = false;
850
851 manager_set_server_name(m, f);
852 }
853
854 /* Tell the resolver to reread /etc/resolv.conf, in
855 * case it changed. */
856 res_init();
857
858 /* Flush out any previously resolved addresses */
859 server_name_flush_addresses(m->current_server_name);
860
861 log_debug("Resolving %s...", m->current_server_name->string);
862
863 r = resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, NULL, m);
864 if (r < 0)
865 return log_error_errno(r, "Failed to create resolver: %m");
866
867 return 1;
868 }
869
870 r = manager_begin(m);
871 if (r < 0)
872 return r;
873
874 return 1;
875 }
876
877 void manager_disconnect(Manager *m) {
878 assert(m);
879
880 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
881
882 m->event_timer = sd_event_source_unref(m->event_timer);
883
884 manager_listen_stop(m);
885
886 m->event_clock_watch = sd_event_source_disable_unref(m->event_clock_watch);
887
888 m->event_timeout = sd_event_source_unref(m->event_timeout);
889
890 (void) sd_notify(false, "STATUS=Idle.");
891 }
892
893 void manager_flush_server_names(Manager *m, ServerType t) {
894 assert(m);
895
896 if (t == SERVER_SYSTEM)
897 while (m->system_servers)
898 server_name_free(m->system_servers);
899
900 if (t == SERVER_LINK)
901 while (m->link_servers)
902 server_name_free(m->link_servers);
903
904 if (t == SERVER_FALLBACK)
905 while (m->fallback_servers)
906 server_name_free(m->fallback_servers);
907 }
908
909 Manager* manager_free(Manager *m) {
910 if (!m)
911 return NULL;
912
913 manager_disconnect(m);
914 manager_flush_server_names(m, SERVER_SYSTEM);
915 manager_flush_server_names(m, SERVER_LINK);
916 manager_flush_server_names(m, SERVER_FALLBACK);
917
918 sd_event_source_unref(m->event_retry);
919
920 sd_event_source_unref(m->network_event_source);
921 sd_network_monitor_unref(m->network_monitor);
922
923 sd_event_source_unref(m->event_save_time);
924
925 sd_resolve_unref(m->resolve);
926 sd_event_unref(m->event);
927
928 sd_bus_flush_close_unref(m->bus);
929
930 return mfree(m);
931 }
932
933 static int manager_network_read_link_servers(Manager *m) {
934 _cleanup_strv_free_ char **ntp = NULL;
935 ServerName *n, *nx;
936 char **i;
937 bool changed = false;
938 int r;
939
940 assert(m);
941
942 r = sd_network_get_ntp(&ntp);
943 if (r < 0) {
944 if (r == -ENOMEM)
945 log_oom();
946 else
947 log_debug_errno(r, "Failed to get link NTP servers: %m");
948 goto clear;
949 }
950
951 LIST_FOREACH(names, n, m->link_servers)
952 n->marked = true;
953
954 STRV_FOREACH(i, ntp) {
955 bool found = false;
956
957 r = dns_name_is_valid_or_address(*i);
958 if (r < 0) {
959 log_error_errno(r, "Failed to check validity of NTP server name or address '%s': %m", *i);
960 goto clear;
961 } else if (r == 0) {
962 log_error("Invalid NTP server name or address, ignoring: %s", *i);
963 continue;
964 }
965
966 LIST_FOREACH(names, n, m->link_servers)
967 if (streq(n->string, *i)) {
968 n->marked = false;
969 found = true;
970 break;
971 }
972
973 if (!found) {
974 r = server_name_new(m, NULL, SERVER_LINK, *i);
975 if (r < 0) {
976 log_oom();
977 goto clear;
978 }
979
980 changed = true;
981 }
982 }
983
984 LIST_FOREACH_SAFE(names, n, nx, m->link_servers)
985 if (n->marked) {
986 server_name_free(n);
987 changed = true;
988 }
989
990 return changed;
991
992 clear:
993 manager_flush_server_names(m, SERVER_LINK);
994 return r;
995 }
996
997 static bool manager_is_connected(Manager *m) {
998 /* Return true when the manager is sending a request, resolving a server name, or
999 * in a poll interval. */
1000 return m->server_socket >= 0 || m->resolve_query || m->event_timer;
1001 }
1002
1003 static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
1004 Manager *m = userdata;
1005 bool changed, connected, online;
1006 int r;
1007
1008 assert(m);
1009
1010 sd_network_monitor_flush(m->network_monitor);
1011
1012 /* When manager_network_read_link_servers() failed, we assume that the servers are changed. */
1013 changed = manager_network_read_link_servers(m);
1014
1015 /* check if the machine is online */
1016 online = network_is_online();
1017
1018 /* check if the client is currently connected */
1019 connected = manager_is_connected(m);
1020
1021 if (connected && !online) {
1022 log_info("No network connectivity, watching for changes.");
1023 manager_disconnect(m);
1024
1025 } else if ((!connected || changed) && online) {
1026 log_info("Network configuration changed, trying to establish connection.");
1027
1028 if (m->current_server_address)
1029 r = manager_begin(m);
1030 else
1031 r = manager_connect(m);
1032 if (r < 0)
1033 return r;
1034 }
1035
1036 return 0;
1037 }
1038
1039 static int manager_network_monitor_listen(Manager *m) {
1040 int r, fd, events;
1041
1042 assert(m);
1043
1044 r = sd_network_monitor_new(&m->network_monitor, NULL);
1045 if (r == -ENOENT) {
1046 log_info("systemd does not appear to be running, not listening for systemd-networkd events.");
1047 return 0;
1048 }
1049 if (r < 0)
1050 return r;
1051
1052 fd = sd_network_monitor_get_fd(m->network_monitor);
1053 if (fd < 0)
1054 return fd;
1055
1056 events = sd_network_monitor_get_events(m->network_monitor);
1057 if (events < 0)
1058 return events;
1059
1060 r = sd_event_add_io(m->event, &m->network_event_source, fd, events, manager_network_event_handler, m);
1061 if (r < 0)
1062 return r;
1063
1064 return 0;
1065 }
1066
1067 int manager_new(Manager **ret) {
1068 _cleanup_(manager_freep) Manager *m = NULL;
1069 int r;
1070
1071 assert(ret);
1072
1073 m = new(Manager, 1);
1074 if (!m)
1075 return -ENOMEM;
1076
1077 *m = (Manager) {
1078 .root_distance_max_usec = NTP_ROOT_DISTANCE_MAX_USEC,
1079 .poll_interval_min_usec = NTP_POLL_INTERVAL_MIN_USEC,
1080 .poll_interval_max_usec = NTP_POLL_INTERVAL_MAX_USEC,
1081
1082 .connection_retry_usec = DEFAULT_CONNECTION_RETRY_USEC,
1083
1084 .server_socket = -1,
1085
1086 .ratelimit = (RateLimit) {
1087 RATELIMIT_INTERVAL_USEC,
1088 RATELIMIT_BURST
1089 },
1090
1091 .save_time_interval_usec = DEFAULT_SAVE_TIME_INTERVAL_USEC,
1092 };
1093
1094 r = sd_event_default(&m->event);
1095 if (r < 0)
1096 return r;
1097
1098 (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
1099 (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
1100
1101 (void) sd_event_set_watchdog(m->event, true);
1102
1103 r = sd_resolve_default(&m->resolve);
1104 if (r < 0)
1105 return r;
1106
1107 r = sd_resolve_attach_event(m->resolve, m->event, 0);
1108 if (r < 0)
1109 return r;
1110
1111 r = manager_network_monitor_listen(m);
1112 if (r < 0)
1113 return r;
1114
1115 (void) manager_network_read_link_servers(m);
1116
1117 *ret = TAKE_PTR(m);
1118
1119 return 0;
1120 }
1121
1122 static int manager_save_time_handler(sd_event_source *s, uint64_t usec, void *userdata) {
1123 Manager *m = userdata;
1124
1125 assert(m);
1126
1127 (void) manager_save_time_and_rearm(m);
1128 return 0;
1129 }
1130
1131 int manager_setup_save_time_event(Manager *m) {
1132 int r;
1133
1134 assert(m);
1135 assert(!m->event_save_time);
1136
1137 if (m->save_time_interval_usec == USEC_INFINITY)
1138 return 0;
1139
1140 /* NB: we'll accumulate scheduling latencies here, but this doesn't matter */
1141 r = sd_event_add_time_relative(
1142 m->event, &m->event_save_time,
1143 clock_boottime_or_monotonic(),
1144 m->save_time_interval_usec,
1145 10 * USEC_PER_SEC,
1146 manager_save_time_handler, m);
1147 if (r < 0)
1148 return log_error_errno(r, "Failed to add save time event: %m");
1149
1150 (void) sd_event_source_set_description(m->event_save_time, "save-time");
1151
1152 return 0;
1153 }
1154
1155 static int manager_save_time_and_rearm(Manager *m) {
1156 int r;
1157
1158 assert(m);
1159
1160 r = touch(CLOCK_FILE);
1161 if (r < 0)
1162 log_debug_errno(r, "Failed to update " CLOCK_FILE ", ignoring: %m");
1163
1164 m->save_on_exit = true;
1165
1166 if (m->save_time_interval_usec != USEC_INFINITY) {
1167 r = sd_event_source_set_time_relative(m->event_save_time, m->save_time_interval_usec);
1168 if (r < 0)
1169 return log_error_errno(r, "Failed to rearm save time event: %m");
1170
1171 r = sd_event_source_set_enabled(m->event_save_time, SD_EVENT_ONESHOT);
1172 if (r < 0)
1173 return log_error_errno(r, "Failed to enable save time event: %m");
1174 }
1175
1176 return 0;
1177 }
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