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-rw-r--r--src/timesync/timesyncd-manager.c1287
1 files changed, 1287 insertions, 0 deletions
diff --git a/src/timesync/timesyncd-manager.c b/src/timesync/timesyncd-manager.c
new file mode 100644
index 0000000..1998ba9
--- /dev/null
+++ b/src/timesync/timesyncd-manager.c
@@ -0,0 +1,1287 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <math.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <resolv.h>
+#include <stdlib.h>
+#include <sys/timerfd.h>
+#include <sys/timex.h>
+#include <sys/types.h>
+
+#include "sd-daemon.h"
+#include "sd-messages.h"
+
+#include "alloc-util.h"
+#include "bus-polkit.h"
+#include "common-signal.h"
+#include "dns-domain.h"
+#include "event-util.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "fs-util.h"
+#include "list.h"
+#include "log.h"
+#include "logarithm.h"
+#include "network-util.h"
+#include "ratelimit.h"
+#include "resolve-private.h"
+#include "random-util.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "time-util.h"
+#include "timesyncd-conf.h"
+#include "timesyncd-manager.h"
+#include "user-util.h"
+
+#ifndef ADJ_SETOFFSET
+#define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
+#endif
+
+/* Expected accuracy of time synchronization; used to adjust the poll interval */
+#define NTP_ACCURACY_SEC 0.2
+
+/*
+ * Maximum delta in seconds which the system clock is gradually adjusted
+ * (slewed) to approach the network time. Deltas larger that this are set by
+ * letting the system time jump. The kernel's limit for adjtime is 0.5s.
+ */
+#define NTP_MAX_ADJUST 0.4
+
+/* Default of maximum acceptable root distance in microseconds. */
+#define NTP_ROOT_DISTANCE_MAX_USEC (5 * USEC_PER_SEC)
+
+/* Maximum number of missed replies before selecting another source. */
+#define NTP_MAX_MISSED_REPLIES 2
+
+#define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
+#define RATELIMIT_BURST 10
+
+#define TIMEOUT_USEC (10*USEC_PER_SEC)
+
+static int manager_arm_timer(Manager *m, usec_t next);
+static int manager_clock_watch_setup(Manager *m);
+static int manager_listen_setup(Manager *m);
+static void manager_listen_stop(Manager *m);
+static int manager_save_time_and_rearm(Manager *m, usec_t t);
+
+static double ntp_ts_short_to_d(const struct ntp_ts_short *ts) {
+ return be16toh(ts->sec) + (be16toh(ts->frac) / 65536.0);
+}
+
+static double ntp_ts_to_d(const struct ntp_ts *ts) {
+ return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
+}
+
+static double ts_to_d(const struct timespec *ts) {
+ return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
+}
+
+static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
+ _cleanup_free_ char *pretty = NULL;
+ Manager *m = ASSERT_PTR(userdata);
+
+ assert(m->current_server_name);
+ assert(m->current_server_address);
+
+ server_address_pretty(m->current_server_address, &pretty);
+ log_info("Timed out waiting for reply from %s (%s).", strna(pretty), m->current_server_name->string);
+
+ return manager_connect(m);
+}
+
+static int manager_send_request(Manager *m) {
+ _cleanup_free_ char *pretty = NULL;
+ struct ntp_msg ntpmsg = {
+ /*
+ * "The client initializes the NTP message header, sends the request
+ * to the server, and strips the time of day from the Transmit
+ * Timestamp field of the reply. For this purpose, all the NTP
+ * header fields are set to 0, except the Mode, VN, and optional
+ * Transmit Timestamp fields."
+ */
+ .field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
+ };
+ ssize_t len;
+ int r;
+
+ assert(m);
+ assert(m->current_server_name);
+ assert(m->current_server_address);
+
+ m->event_timeout = sd_event_source_unref(m->event_timeout);
+
+ r = manager_listen_setup(m);
+ if (r < 0) {
+ log_warning_errno(r, "Failed to set up connection socket: %m");
+ return manager_connect(m);
+ }
+
+ /*
+ * Generate a random number as transmit timestamp, to ensure we get
+ * a full 64 bits of entropy to make it hard for off-path attackers
+ * to inject random time to us.
+ */
+ random_bytes(&m->request_nonce, sizeof(m->request_nonce));
+ ntpmsg.trans_time = m->request_nonce;
+
+ server_address_pretty(m->current_server_address, &pretty);
+
+ /*
+ * Record the transmit timestamp. This should be as close as possible to
+ * the send-to to ensure the timestamp is reasonably accurate
+ */
+ assert_se(clock_gettime(CLOCK_BOOTTIME, &m->trans_time_mon) >= 0);
+ assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
+
+ len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
+ if (len == sizeof(ntpmsg)) {
+ m->pending = true;
+ log_debug("Sent NTP request to %s (%s).", strna(pretty), m->current_server_name->string);
+ } else {
+ log_debug_errno(errno, "Sending NTP request to %s (%s) failed: %m", strna(pretty), m->current_server_name->string);
+ return manager_connect(m);
+ }
+
+ /* re-arm timer with increasing timeout, in case the packets never arrive back */
+ if (m->retry_interval == 0)
+ m->retry_interval = NTP_RETRY_INTERVAL_MIN_USEC;
+ else
+ m->retry_interval = MIN(m->retry_interval * 4/3, NTP_RETRY_INTERVAL_MAX_USEC);
+
+ r = manager_arm_timer(m, m->retry_interval);
+ if (r < 0)
+ return log_error_errno(r, "Failed to rearm timer: %m");
+
+ m->missed_replies++;
+ if (m->missed_replies > NTP_MAX_MISSED_REPLIES) {
+ r = sd_event_add_time(
+ m->event,
+ &m->event_timeout,
+ CLOCK_BOOTTIME,
+ now(CLOCK_BOOTTIME) + TIMEOUT_USEC, 0,
+ manager_timeout, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to arm timeout timer: %m");
+ }
+
+ return 0;
+}
+
+static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
+ Manager *m = ASSERT_PTR(userdata);
+
+ return manager_send_request(m);
+}
+
+static int manager_arm_timer(Manager *m, usec_t next) {
+ int r;
+
+ assert(m);
+
+ if (next == 0) {
+ m->event_timer = sd_event_source_unref(m->event_timer);
+ return 0;
+ }
+
+ if (m->event_timer) {
+ r = sd_event_source_set_time_relative(m->event_timer, next);
+ if (r < 0)
+ return r;
+
+ return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
+ }
+
+ return sd_event_add_time_relative(
+ m->event,
+ &m->event_timer,
+ CLOCK_BOOTTIME,
+ next, 0,
+ manager_timer, m);
+}
+
+static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
+ Manager *m = ASSERT_PTR(userdata);
+
+ /* rearm timer */
+ manager_clock_watch_setup(m);
+
+ /* skip our own jumps */
+ if (m->jumped) {
+ m->jumped = false;
+ return 0;
+ }
+
+ /* resync */
+ log_debug("System time changed. Resyncing.");
+ m->poll_resync = true;
+
+ return manager_send_request(m);
+}
+
+/* wake up when the system time changes underneath us */
+static int manager_clock_watch_setup(Manager *m) {
+ int r;
+
+ assert(m);
+
+ m->event_clock_watch = sd_event_source_disable_unref(m->event_clock_watch);
+
+ r = event_add_time_change(m->event, &m->event_clock_watch, manager_clock_watch, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create clock watch event source: %m");
+
+ return 0;
+}
+
+static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
+ struct timex tmx;
+
+ assert(m);
+
+ /* For small deltas, tell the kernel to gradually adjust the system clock to the NTP time, larger
+ * deltas are just directly set. */
+ if (fabs(offset) < NTP_MAX_ADJUST) {
+ tmx = (struct timex) {
+ .modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR,
+ .status = STA_PLL,
+ .offset = offset * NSEC_PER_SEC,
+ .constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4,
+ };
+
+ log_debug(" adjust (slew): %+.3f sec", offset);
+ } else {
+ tmx = (struct timex) {
+ .modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET | ADJ_MAXERROR | ADJ_ESTERROR,
+
+ /* ADJ_NANO uses nanoseconds in the microseconds field */
+ .time.tv_sec = (long)offset,
+ .time.tv_usec = (offset - (double) (long) offset) * NSEC_PER_SEC,
+ };
+
+ /* the kernel expects -0.3s as {-1, 7000.000.000} */
+ if (tmx.time.tv_usec < 0) {
+ tmx.time.tv_sec -= 1;
+ tmx.time.tv_usec += NSEC_PER_SEC;
+ }
+
+ m->jumped = true;
+ log_debug(" adjust (jump): %+.3f sec", offset);
+ }
+
+ /* An unset STA_UNSYNC will enable the kernel's 11-minute mode, which syncs the system time
+ * periodically to the RTC.
+ *
+ * In case the RTC runs in local time, never touch the RTC, we have no way to properly handle
+ * daylight saving changes and mobile devices moving between time zones. */
+ if (m->rtc_local_time)
+ tmx.status |= STA_UNSYNC;
+
+ switch (leap_sec) {
+ case 1:
+ tmx.status |= STA_INS;
+ break;
+ case -1:
+ tmx.status |= STA_DEL;
+ break;
+ }
+
+ if (clock_adjtime(CLOCK_REALTIME, &tmx) < 0)
+ return -errno;
+
+ m->drift_freq = tmx.freq;
+
+ log_debug(" status : %04i %s\n"
+ " time now : %"PRI_TIME".%03"PRI_USEC"\n"
+ " constant : %"PRI_TIMEX"\n"
+ " offset : %+.3f sec\n"
+ " freq offset : %+"PRI_TIMEX" (%+"PRI_TIMEX" ppm)\n",
+ tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
+ tmx.time.tv_sec, tmx.time.tv_usec / NSEC_PER_MSEC,
+ tmx.constant,
+ (double)tmx.offset / NSEC_PER_SEC,
+ tmx.freq, tmx.freq / 65536);
+
+ return 0;
+}
+
+static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
+ unsigned i, idx_cur, idx_new, idx_min;
+ double jitter;
+ double j;
+
+ assert(m);
+
+ m->packet_count++;
+
+ /* ignore initial sample */
+ if (m->packet_count == 1)
+ return false;
+
+ /* store the current data in our samples array */
+ idx_cur = m->samples_idx;
+ idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
+ m->samples_idx = idx_new;
+ m->samples[idx_new].offset = offset;
+ m->samples[idx_new].delay = delay;
+
+ /* calculate new jitter value from the RMS differences relative to the lowest delay sample */
+ jitter = m->samples_jitter;
+ for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
+ if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
+ idx_min = i;
+
+ j = 0;
+ for (i = 0; i < ELEMENTSOF(m->samples); i++)
+ j += pow(m->samples[i].offset - m->samples[idx_min].offset, 2);
+ m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
+
+ /* ignore samples when resyncing */
+ if (m->poll_resync)
+ return false;
+
+ /* always accept offset if we are farther off than the round-trip delay */
+ if (fabs(offset) > delay)
+ return false;
+
+ /* we need a few samples before looking at them */
+ if (m->packet_count < 4)
+ return false;
+
+ /* do not accept anything worse than the maximum possible error of the best sample */
+ if (fabs(offset) > m->samples[idx_min].delay)
+ return true;
+
+ /* compare the difference between the current offset to the previous offset and jitter */
+ return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
+}
+
+static void manager_adjust_poll(Manager *m, double offset, bool spike) {
+ assert(m);
+
+ if (m->poll_resync) {
+ m->poll_interval_usec = m->poll_interval_min_usec;
+ m->poll_resync = false;
+ return;
+ }
+
+ /* set to minimal poll interval */
+ if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
+ m->poll_interval_usec = m->poll_interval_min_usec;
+ return;
+ }
+
+ /* increase polling interval */
+ if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
+ if (m->poll_interval_usec < m->poll_interval_max_usec)
+ m->poll_interval_usec *= 2;
+ return;
+ }
+
+ /* decrease polling interval */
+ if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
+ if (m->poll_interval_usec > m->poll_interval_min_usec)
+ m->poll_interval_usec /= 2;
+ return;
+ }
+}
+
+static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
+ Manager *m = ASSERT_PTR(userdata);
+ struct ntp_msg ntpmsg;
+
+ struct iovec iov = {
+ .iov_base = &ntpmsg,
+ .iov_len = sizeof(ntpmsg),
+ };
+ /* This needs to be initialized with zero. See #20741. */
+ CMSG_BUFFER_TYPE(CMSG_SPACE_TIMESPEC) control = {};
+ union sockaddr_union server_addr;
+ struct msghdr msghdr = {
+ .msg_iov = &iov,
+ .msg_iovlen = 1,
+ .msg_control = &control,
+ .msg_controllen = sizeof(control),
+ .msg_name = &server_addr,
+ .msg_namelen = sizeof(server_addr),
+ };
+ struct timespec *recv_time;
+ triple_timestamp dts;
+ ssize_t len;
+ double origin, receive, trans, dest, delay, offset, root_distance;
+ bool spike;
+ int leap_sec, r;
+
+ assert(source);
+
+ if (revents & (EPOLLHUP|EPOLLERR)) {
+ log_warning("Server connection returned error.");
+ return manager_connect(m);
+ }
+
+ len = recvmsg_safe(fd, &msghdr, MSG_DONTWAIT);
+ if (len == -EAGAIN)
+ return 0;
+ if (len < 0) {
+ log_warning_errno(len, "Error receiving message, disconnecting: %m");
+ return manager_connect(m);
+ }
+
+ /* Too short or too long packet? */
+ if (iov.iov_len < sizeof(struct ntp_msg) || (msghdr.msg_flags & MSG_TRUNC)) {
+ log_warning("Invalid response from server. Disconnecting.");
+ return manager_connect(m);
+ }
+
+ if (!m->current_server_name ||
+ !m->current_server_address ||
+ !sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
+ log_debug("Response from unknown server.");
+ return 0;
+ }
+
+ recv_time = CMSG_FIND_AND_COPY_DATA(&msghdr, SOL_SOCKET, SCM_TIMESTAMPNS, struct timespec);
+ if (!recv_time)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Packet timestamp missing.");
+
+ if (!m->pending) {
+ log_debug("Unexpected reply. Ignoring.");
+ return 0;
+ }
+
+ m->missed_replies = 0;
+
+ /* check the transmit request nonce was properly returned in the origin_time field */
+ if (ntpmsg.origin_time.sec != m->request_nonce.sec || ntpmsg.origin_time.frac != m->request_nonce.frac) {
+ log_debug("Invalid reply; not our transmit time. Ignoring.");
+ return 0;
+ }
+
+ m->event_timeout = sd_event_source_unref(m->event_timeout);
+
+ if (be32toh(ntpmsg.recv_time.sec) < TIME_EPOCH + OFFSET_1900_1970 ||
+ be32toh(ntpmsg.trans_time.sec) < TIME_EPOCH + OFFSET_1900_1970) {
+ log_debug("Invalid reply, returned times before epoch. Ignoring.");
+ return manager_connect(m);
+ }
+
+ if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC ||
+ ntpmsg.stratum == 0 || ntpmsg.stratum >= 16) {
+ log_debug("Server is not synchronized. Disconnecting.");
+ return manager_connect(m);
+ }
+
+ if (!IN_SET(NTP_FIELD_VERSION(ntpmsg.field), 3, 4)) {
+ log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
+ return manager_connect(m);
+ }
+
+ if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
+ log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
+ return manager_connect(m);
+ }
+
+ root_distance = ntp_ts_short_to_d(&ntpmsg.root_delay) / 2 + ntp_ts_short_to_d(&ntpmsg.root_dispersion);
+ if (root_distance > (double) m->root_distance_max_usec / (double) USEC_PER_SEC) {
+ log_info("Server has too large root distance. Disconnecting.");
+ return manager_connect(m);
+ }
+
+ /* valid packet */
+ m->pending = false;
+ m->retry_interval = 0;
+
+ /* Stop listening */
+ manager_listen_stop(m);
+
+ /* announce leap seconds */
+ if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
+ leap_sec = 1;
+ else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
+ leap_sec = -1;
+ else
+ leap_sec = 0;
+
+ /*
+ * "Timestamp Name ID When Generated
+ * ------------------------------------------------------------
+ * Originate Timestamp T1 time request sent by client
+ * Receive Timestamp T2 time request received by server
+ * Transmit Timestamp T3 time reply sent by server
+ * Destination Timestamp T4 time reply received by client
+ *
+ * The round-trip delay, d, and system clock offset, t, are defined as:
+ * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
+ */
+ origin = ts_to_d(&m->trans_time) + OFFSET_1900_1970;
+ receive = ntp_ts_to_d(&ntpmsg.recv_time);
+ trans = ntp_ts_to_d(&ntpmsg.trans_time);
+ dest = ts_to_d(recv_time) + OFFSET_1900_1970;
+
+ offset = ((receive - origin) + (trans - dest)) / 2;
+ delay = (dest - origin) - (trans - receive);
+
+ spike = manager_sample_spike_detection(m, offset, delay);
+
+ manager_adjust_poll(m, offset, spike);
+
+ log_debug("NTP response:\n"
+ " leap : %i\n"
+ " version : %i\n"
+ " mode : %i\n"
+ " stratum : %u\n"
+ " precision : %.6f sec (%i)\n"
+ " root distance: %.6f sec\n"
+ " reference : %.4s\n"
+ " origin : %.3f\n"
+ " receive : %.3f\n"
+ " transmit : %.3f\n"
+ " dest : %.3f\n"
+ " offset : %+.3f sec\n"
+ " delay : %+.3f sec\n"
+ " packet count : %"PRIu64"\n"
+ " jitter : %.3f%s\n"
+ " poll interval: " USEC_FMT "\n",
+ NTP_FIELD_LEAP(ntpmsg.field),
+ NTP_FIELD_VERSION(ntpmsg.field),
+ NTP_FIELD_MODE(ntpmsg.field),
+ ntpmsg.stratum,
+ exp2(ntpmsg.precision), ntpmsg.precision,
+ root_distance,
+ ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
+ origin - OFFSET_1900_1970,
+ receive - OFFSET_1900_1970,
+ trans - OFFSET_1900_1970,
+ dest - OFFSET_1900_1970,
+ offset, delay,
+ m->packet_count,
+ m->samples_jitter, spike ? " spike" : "",
+ m->poll_interval_usec / USEC_PER_SEC);
+
+ /* Get current monotonic/realtime clocks immediately before adjusting the latter */
+ triple_timestamp_now(&dts);
+
+ if (!spike) {
+ /* Fix up our idea of the time. */
+ dts.realtime = (usec_t) (dts.realtime + offset * USEC_PER_SEC);
+
+ r = manager_adjust_clock(m, offset, leap_sec);
+ if (r < 0)
+ log_error_errno(r, "Failed to call clock_adjtime(): %m");
+
+ (void) manager_save_time_and_rearm(m, dts.realtime);
+
+ /* If touch fails, there isn't much we can do. Maybe it'll work next time. */
+ r = touch("/run/systemd/timesync/synchronized");
+ if (r < 0)
+ log_debug_errno(r, "Failed to touch /run/systemd/timesync/synchronized, ignoring: %m");
+ }
+
+ /* Save NTP response */
+ m->ntpmsg = ntpmsg;
+ m->origin_time = m->trans_time;
+ m->dest_time = *recv_time;
+ m->spike = spike;
+
+ log_debug("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+"PRIi64"ppm%s",
+ m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_freq / 65536,
+ spike ? " (ignored)" : "");
+
+ if (sd_bus_is_ready(m->bus) > 0)
+ (void) sd_bus_emit_properties_changed(
+ m->bus,
+ "/org/freedesktop/timesync1",
+ "org.freedesktop.timesync1.Manager",
+ "NTPMessage",
+ NULL);
+
+ if (!m->talking) {
+ _cleanup_free_ char *pretty = NULL;
+
+ m->talking = true;
+
+ (void) server_address_pretty(m->current_server_address, &pretty);
+
+ log_info("Contacted time server %s (%s).", strna(pretty), m->current_server_name->string);
+ (void) sd_notifyf(false, "STATUS=Contacted time server %s (%s).", strna(pretty), m->current_server_name->string);
+ }
+
+ if (!spike && !m->synchronized) {
+ m->synchronized = true;
+
+ log_struct(LOG_INFO,
+ LOG_MESSAGE("Initial clock synchronization to %s.",
+ FORMAT_TIMESTAMP_STYLE(dts.realtime, TIMESTAMP_US)),
+ "MESSAGE_ID=" SD_MESSAGE_TIME_SYNC_STR,
+ "MONOTONIC_USEC=" USEC_FMT, dts.monotonic,
+ "REALTIME_USEC=" USEC_FMT, dts.realtime,
+ "BOOTTIME_USEC=" USEC_FMT, dts.boottime);
+ }
+
+ r = manager_arm_timer(m, m->poll_interval_usec);
+ if (r < 0)
+ return log_error_errno(r, "Failed to rearm timer: %m");
+
+ return 0;
+}
+
+static int manager_listen_setup(Manager *m) {
+ union sockaddr_union addr = {};
+ int r;
+
+ assert(m);
+
+ if (m->server_socket >= 0)
+ return 0;
+
+ assert(!m->event_receive);
+ assert(m->current_server_address);
+
+ addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
+
+ m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
+ if (m->server_socket < 0)
+ return -errno;
+
+ r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
+ if (r < 0)
+ return -errno;
+
+ r = setsockopt_int(m->server_socket, SOL_SOCKET, SO_TIMESTAMPNS, true);
+ if (r < 0)
+ return r;
+
+ (void) socket_set_option(m->server_socket, addr.sa.sa_family, IP_TOS, IPV6_TCLASS, IPTOS_DSCP_EF);
+
+ return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
+}
+
+static void manager_listen_stop(Manager *m) {
+ assert(m);
+
+ m->event_receive = sd_event_source_unref(m->event_receive);
+ m->server_socket = safe_close(m->server_socket);
+}
+
+static int manager_begin(Manager *m) {
+ _cleanup_free_ char *pretty = NULL;
+ int r;
+
+ assert(m);
+ assert_return(m->current_server_name, -EHOSTUNREACH);
+ assert_return(m->current_server_address, -EHOSTUNREACH);
+
+ m->talking = false;
+ m->missed_replies = NTP_MAX_MISSED_REPLIES;
+ if (m->poll_interval_usec == 0)
+ m->poll_interval_usec = m->poll_interval_min_usec;
+
+ server_address_pretty(m->current_server_address, &pretty);
+ log_debug("Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
+ (void) sd_notifyf(false, "STATUS=Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
+
+ r = manager_clock_watch_setup(m);
+ if (r < 0)
+ return r;
+
+ return manager_send_request(m);
+}
+
+void manager_set_server_name(Manager *m, ServerName *n) {
+ assert(m);
+
+ if (m->current_server_name == n)
+ return;
+
+ m->current_server_name = n;
+ m->current_server_address = NULL;
+
+ manager_disconnect(m);
+
+ if (n)
+ log_debug("Selected server %s.", n->string);
+}
+
+void manager_set_server_address(Manager *m, ServerAddress *a) {
+ assert(m);
+
+ if (m->current_server_address == a)
+ return;
+
+ m->current_server_address = a;
+ /* If a is NULL, we are just clearing the address, without
+ * changing the name. Keep the existing name in that case. */
+ if (a)
+ m->current_server_name = a->name;
+
+ manager_disconnect(m);
+
+ if (a) {
+ _cleanup_free_ char *pretty = NULL;
+ server_address_pretty(a, &pretty);
+ log_debug("Selected address %s of server %s.", strna(pretty), a->name->string);
+ }
+}
+
+static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, Manager *m) {
+ int r;
+
+ assert(q);
+ assert(m);
+ assert(m->current_server_name);
+
+ m->resolve_query = sd_resolve_query_unref(m->resolve_query);
+
+ if (ret != 0) {
+ log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
+
+ /* Try next host */
+ return manager_connect(m);
+ }
+
+ for (; ai; ai = ai->ai_next) {
+ _cleanup_free_ char *pretty = NULL;
+ ServerAddress *a;
+
+ assert(ai->ai_addr);
+ assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
+
+ if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
+ log_debug("Ignoring unsuitable address protocol for %s.", m->current_server_name->string);
+ continue;
+ }
+
+ r = server_address_new(m->current_server_name, &a, (const union sockaddr_union*) ai->ai_addr, ai->ai_addrlen);
+ if (r < 0)
+ return log_error_errno(r, "Failed to add server address: %m");
+
+ server_address_pretty(a, &pretty);
+ log_debug("Resolved address %s for %s.", pretty, m->current_server_name->string);
+ }
+
+ if (!m->current_server_name->addresses) {
+ log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
+
+ /* Try next host */
+ return manager_connect(m);
+ }
+
+ manager_set_server_address(m, m->current_server_name->addresses);
+
+ return manager_begin(m);
+}
+
+static int manager_retry_connect(sd_event_source *source, usec_t usec, void *userdata) {
+ Manager *m = ASSERT_PTR(userdata);
+
+ return manager_connect(m);
+}
+
+int manager_connect(Manager *m) {
+ int r;
+
+ assert(m);
+
+ manager_disconnect(m);
+
+ m->event_retry = sd_event_source_unref(m->event_retry);
+ if (!ratelimit_below(&m->ratelimit)) {
+ log_debug("Delaying attempts to contact servers.");
+
+ r = sd_event_add_time_relative(m->event, &m->event_retry, CLOCK_BOOTTIME, m->connection_retry_usec,
+ 0, manager_retry_connect, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create retry timer: %m");
+
+ return 0;
+ }
+
+ /* If we already are operating on some address, switch to the
+ * next one. */
+ if (m->current_server_address && m->current_server_address->addresses_next)
+ manager_set_server_address(m, m->current_server_address->addresses_next);
+ else {
+ /* Hmm, we are through all addresses, let's look for the next host instead */
+ if (m->current_server_name && m->current_server_name->names_next)
+ manager_set_server_name(m, m->current_server_name->names_next);
+ else {
+ ServerName *f;
+ bool restart = true;
+
+ /* Our current server name list is exhausted,
+ * let's find the next one to iterate. First we try the runtime list, then the system list,
+ * then the link list. After having processed the link list we jump back to the system list
+ * if no runtime server list.
+ * However, if all lists are empty, we change to the fallback list. */
+ if (!m->current_server_name || m->current_server_name->type == SERVER_LINK) {
+ f = m->runtime_servers;
+ if (!f)
+ f = m->system_servers;
+ if (!f)
+ f = m->link_servers;
+ } else {
+ f = m->link_servers;
+ if (f)
+ restart = false;
+ else {
+ f = m->runtime_servers;
+ if (!f)
+ f = m->system_servers;
+ }
+ }
+
+ if (!f)
+ f = m->fallback_servers;
+
+ if (!f) {
+ manager_set_server_name(m, NULL);
+ log_debug("No server found.");
+ return 0;
+ }
+
+ if (restart && !m->exhausted_servers && m->poll_interval_usec > 0) {
+ log_debug("Waiting after exhausting servers.");
+ r = sd_event_add_time_relative(m->event, &m->event_retry, CLOCK_BOOTTIME, m->poll_interval_usec, 0, manager_retry_connect, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create retry timer: %m");
+
+ m->exhausted_servers = true;
+
+ /* Increase the polling interval */
+ if (m->poll_interval_usec < m->poll_interval_max_usec)
+ m->poll_interval_usec *= 2;
+
+ return 0;
+ }
+
+ m->exhausted_servers = false;
+
+ manager_set_server_name(m, f);
+ }
+
+ /* Tell the resolver to reread /etc/resolv.conf, in
+ * case it changed. */
+ res_init();
+
+ /* Flush out any previously resolved addresses */
+ server_name_flush_addresses(m->current_server_name);
+
+ log_debug("Resolving %s...", m->current_server_name->string);
+
+ struct addrinfo hints = {
+ .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
+ .ai_socktype = SOCK_DGRAM,
+ .ai_family = socket_ipv6_is_supported() ? AF_UNSPEC : AF_INET,
+ };
+
+ r = resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, NULL, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create resolver: %m");
+
+ return 1;
+ }
+
+ r = manager_begin(m);
+ if (r < 0)
+ return r;
+
+ return 1;
+}
+
+void manager_disconnect(Manager *m) {
+ assert(m);
+
+ m->resolve_query = sd_resolve_query_unref(m->resolve_query);
+
+ m->event_timer = sd_event_source_unref(m->event_timer);
+
+ manager_listen_stop(m);
+
+ m->event_clock_watch = sd_event_source_disable_unref(m->event_clock_watch);
+
+ m->event_timeout = sd_event_source_unref(m->event_timeout);
+
+ (void) sd_notify(false, "STATUS=Idle.");
+}
+
+void manager_flush_server_names(Manager *m, ServerType t) {
+ assert(m);
+
+ if (t == SERVER_SYSTEM)
+ while (m->system_servers)
+ server_name_free(m->system_servers);
+
+ if (t == SERVER_LINK)
+ while (m->link_servers)
+ server_name_free(m->link_servers);
+
+ if (t == SERVER_FALLBACK)
+ while (m->fallback_servers)
+ server_name_free(m->fallback_servers);
+
+ if (t == SERVER_RUNTIME)
+ manager_flush_runtime_servers(m);
+}
+
+void manager_flush_runtime_servers(Manager *m) {
+ assert(m);
+
+ while (m->runtime_servers)
+ server_name_free(m->runtime_servers);
+}
+
+Manager* manager_free(Manager *m) {
+ if (!m)
+ return NULL;
+
+ manager_disconnect(m);
+ manager_flush_server_names(m, SERVER_SYSTEM);
+ manager_flush_server_names(m, SERVER_LINK);
+ manager_flush_server_names(m, SERVER_RUNTIME);
+ manager_flush_server_names(m, SERVER_FALLBACK);
+
+ sd_event_source_unref(m->event_retry);
+
+ sd_event_source_unref(m->network_event_source);
+ sd_network_monitor_unref(m->network_monitor);
+
+ sd_event_source_unref(m->event_save_time);
+
+ sd_event_source_unref(m->deferred_ntp_server_event_source);
+
+ sd_resolve_unref(m->resolve);
+ sd_event_unref(m->event);
+
+ sd_bus_flush_close_unref(m->bus);
+
+ bus_verify_polkit_async_registry_free(m->polkit_registry);
+
+ return mfree(m);
+}
+
+static int manager_network_read_link_servers(Manager *m) {
+ _cleanup_strv_free_ char **ntp = NULL;
+ bool changed = false;
+ int r;
+
+ assert(m);
+
+ r = sd_network_get_ntp(&ntp);
+ if (r < 0 && r != -ENODATA) {
+ if (r == -ENOMEM)
+ log_oom();
+ else
+ log_debug_errno(r, "Failed to get link NTP servers: %m");
+ goto clear;
+ }
+
+ LIST_FOREACH(names, n, m->link_servers)
+ n->marked = true;
+
+ STRV_FOREACH(i, ntp) {
+ bool found = false;
+
+ r = dns_name_is_valid_or_address(*i);
+ if (r < 0) {
+ log_error_errno(r, "Failed to check validity of NTP server name or address '%s': %m", *i);
+ goto clear;
+ } else if (r == 0) {
+ log_error("Invalid NTP server name or address, ignoring: %s", *i);
+ continue;
+ }
+
+ LIST_FOREACH(names, n, m->link_servers)
+ if (streq(n->string, *i)) {
+ n->marked = false;
+ found = true;
+ break;
+ }
+
+ if (!found) {
+ r = server_name_new(m, NULL, SERVER_LINK, *i);
+ if (r < 0) {
+ log_oom();
+ goto clear;
+ }
+
+ changed = true;
+ }
+ }
+
+ LIST_FOREACH(names, n, m->link_servers)
+ if (n->marked) {
+ server_name_free(n);
+ changed = true;
+ }
+
+ return changed;
+
+clear:
+ manager_flush_server_names(m, SERVER_LINK);
+ return r;
+}
+
+bool manager_is_connected(Manager *m) {
+ assert(m);
+
+ /* Return true when the manager is sending a request, resolving a server name, or
+ * in a poll interval. */
+ return m->server_socket >= 0 || m->resolve_query || m->event_timer;
+}
+
+static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+ Manager *m = ASSERT_PTR(userdata);
+ bool changed, connected, online;
+ int r;
+
+ sd_network_monitor_flush(m->network_monitor);
+
+ /* When manager_network_read_link_servers() failed, we assume that the servers are changed. */
+ changed = manager_network_read_link_servers(m);
+
+ /* check if the machine is online */
+ online = network_is_online();
+
+ /* check if the client is currently connected */
+ connected = manager_is_connected(m);
+
+ if (connected && !online) {
+ log_info("No network connectivity, watching for changes.");
+ manager_disconnect(m);
+
+ } else if ((!connected || changed) && online) {
+ log_info("Network configuration changed, trying to establish connection.");
+
+ if (m->current_server_address)
+ r = manager_begin(m);
+ else
+ r = manager_connect(m);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int manager_network_monitor_listen(Manager *m) {
+ int r, fd, events;
+
+ assert(m);
+
+ r = sd_network_monitor_new(&m->network_monitor, NULL);
+ if (r == -ENOENT) {
+ log_info("systemd does not appear to be running, not listening for systemd-networkd events.");
+ return 0;
+ }
+ if (r < 0)
+ return r;
+
+ fd = sd_network_monitor_get_fd(m->network_monitor);
+ if (fd < 0)
+ return fd;
+
+ events = sd_network_monitor_get_events(m->network_monitor);
+ if (events < 0)
+ return events;
+
+ r = sd_event_add_io(m->event, &m->network_event_source, fd, events, manager_network_event_handler, m);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int manager_new(Manager **ret) {
+ _cleanup_(manager_freep) Manager *m = NULL;
+ int r;
+
+ assert(ret);
+
+ m = new(Manager, 1);
+ if (!m)
+ return -ENOMEM;
+
+ *m = (Manager) {
+ .root_distance_max_usec = NTP_ROOT_DISTANCE_MAX_USEC,
+ .poll_interval_min_usec = NTP_POLL_INTERVAL_MIN_USEC,
+ .poll_interval_max_usec = NTP_POLL_INTERVAL_MAX_USEC,
+
+ .connection_retry_usec = DEFAULT_CONNECTION_RETRY_USEC,
+
+ .server_socket = -EBADF,
+
+ .ratelimit = (const RateLimit) {
+ RATELIMIT_INTERVAL_USEC,
+ RATELIMIT_BURST
+ },
+
+ .save_time_interval_usec = DEFAULT_SAVE_TIME_INTERVAL_USEC,
+ };
+
+ r = sd_event_default(&m->event);
+ if (r < 0)
+ return r;
+
+ (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
+ (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
+ (void) sd_event_add_signal(m->event, NULL, SIGRTMIN+18, sigrtmin18_handler, NULL);
+
+ r = sd_event_add_memory_pressure(m->event, NULL, NULL, NULL);
+ if (r < 0)
+ log_debug_errno(r, "Failed allocate memory pressure event source, ignoring: %m");
+
+ (void) sd_event_set_watchdog(m->event, true);
+
+ /* Load previous synchronization state */
+ r = access("/run/systemd/timesync/synchronized", F_OK);
+ if (r < 0 && errno != ENOENT)
+ log_debug_errno(errno, "Failed to determine whether /run/systemd/timesync/synchronized exists, ignoring: %m");
+ m->synchronized = r >= 0;
+
+ r = sd_resolve_default(&m->resolve);
+ if (r < 0)
+ return r;
+
+ r = sd_resolve_attach_event(m->resolve, m->event, 0);
+ if (r < 0)
+ return r;
+
+ r = manager_network_monitor_listen(m);
+ if (r < 0)
+ return r;
+
+ (void) manager_network_read_link_servers(m);
+
+ *ret = TAKE_PTR(m);
+
+ return 0;
+}
+
+static int manager_save_time_handler(sd_event_source *s, uint64_t usec, void *userdata) {
+ Manager *m = ASSERT_PTR(userdata);
+
+ (void) manager_save_time_and_rearm(m, USEC_INFINITY);
+ return 0;
+}
+
+int manager_setup_save_time_event(Manager *m) {
+ int r;
+
+ assert(m);
+ assert(!m->event_save_time);
+
+ if (m->save_time_interval_usec == USEC_INFINITY)
+ return 0;
+
+ /* NB: we'll accumulate scheduling latencies here, but this doesn't matter */
+ r = sd_event_add_time_relative(
+ m->event, &m->event_save_time,
+ CLOCK_BOOTTIME,
+ m->save_time_interval_usec,
+ 10 * USEC_PER_SEC,
+ manager_save_time_handler, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to add save time event: %m");
+
+ (void) sd_event_source_set_description(m->event_save_time, "save-time");
+
+ return 0;
+}
+
+static int manager_save_time_and_rearm(Manager *m, usec_t t) {
+ int r;
+
+ assert(m);
+
+ /* Updates the timestamp file to the specified time. If 't' is USEC_INFINITY uses the current system
+ * clock, but otherwise uses the specified timestamp. Note that whenever we acquire an NTP sync the
+ * specified timestamp value might be more accurate than the system clock, since the latter is
+ * subject to slow adjustments. */
+ r = touch_file(CLOCK_FILE, false, t, UID_INVALID, GID_INVALID, MODE_INVALID);
+ if (r < 0)
+ log_debug_errno(r, "Failed to update " CLOCK_FILE ", ignoring: %m");
+
+ m->save_on_exit = true;
+
+ if (m->save_time_interval_usec != USEC_INFINITY) {
+ r = sd_event_source_set_time_relative(m->event_save_time, m->save_time_interval_usec);
+ if (r < 0)
+ return log_error_errno(r, "Failed to rearm save time event: %m");
+
+ r = sd_event_source_set_enabled(m->event_save_time, SD_EVENT_ONESHOT);
+ if (r < 0)
+ return log_error_errno(r, "Failed to enable save time event: %m");
+ }
+
+ return 0;
+}
+
+static const char* ntp_server_property_name[_SERVER_TYPE_MAX] = {
+ [SERVER_SYSTEM] = "SystemNTPServers",
+ [SERVER_FALLBACK] = "FallbackNTPServers",
+ [SERVER_LINK] = "LinkNTPServers",
+ [SERVER_RUNTIME] = "RuntimeNTPServers",
+};
+
+static int ntp_server_emit_changed_strv(Manager *manager, char **properties) {
+ assert(manager);
+ assert(properties);
+
+ if (sd_bus_is_ready(manager->bus) <= 0)
+ return 0;
+
+ return sd_bus_emit_properties_changed_strv(
+ manager->bus,
+ "/org/freedesktop/timesync1",
+ "org.freedesktop.timesync1.Manager",
+ properties);
+}
+
+static int on_deferred_ntp_server(sd_event_source *s, void *userdata) {
+ int r;
+ _cleanup_strv_free_ char **p = NULL;
+ Manager *m = ASSERT_PTR(userdata);
+
+ m->deferred_ntp_server_event_source = sd_event_source_disable_unref(m->deferred_ntp_server_event_source);
+
+ for (int type = SERVER_SYSTEM; type < _SERVER_TYPE_MAX; type++)
+ if (m->ntp_server_change_mask & (1U << type))
+ if (strv_extend(&p, ntp_server_property_name[type]) < 0)
+ log_oom();
+
+ m->ntp_server_change_mask = 0;
+
+ if (strv_isempty(p))
+ return log_error_errno(SYNTHETIC_ERRNO(ENOMEM), "Failed to build ntp server event strv!");
+
+ r = ntp_server_emit_changed_strv(m, p);
+ if (r < 0)
+ log_warning_errno(r, "Could not emit ntp server changed properties, ignoring: %m");
+
+ return 0;
+}
+
+int bus_manager_emit_ntp_server_changed(Manager *m) {
+ int r;
+
+ assert(m);
+
+ if (m->deferred_ntp_server_event_source)
+ return 0;
+
+ if (!m->event)
+ return 0;
+
+ if (IN_SET(sd_event_get_state(m->event), SD_EVENT_FINISHED, SD_EVENT_EXITING))
+ return 0;
+
+ r = sd_event_add_defer(m->event, &m->deferred_ntp_server_event_source, on_deferred_ntp_server, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to allocate ntp server event source: %m");
+
+ (void) sd_event_source_set_description(m->deferred_ntp_server_event_source, "deferred-ntp-server");
+
+ return 1;
+}