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-rw-r--r--src/timesync/timesyncd.c792
1 files changed, 792 insertions, 0 deletions
diff --git a/src/timesync/timesyncd.c b/src/timesync/timesyncd.c
new file mode 100644
index 0000000000..5bd61dd07c
--- /dev/null
+++ b/src/timesync/timesyncd.c
@@ -0,0 +1,792 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2014 Kay Sievers
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdlib.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <time.h>
+#include <math.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <sys/timerfd.h>
+#include <sys/timex.h>
+#include <sys/socket.h>
+
+#include "missing.h"
+#include "util.h"
+#include "sparse-endian.h"
+#include "log.h"
+#include "sd-event.h"
+#include "sd-daemon.h"
+
+#define TIME_T_MAX (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
+
+#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
+
+/*
+ * "A client MUST NOT under any conditions use a poll interval less
+ * than 15 seconds."
+ */
+#define NTP_POLL_INTERVAL_MIN_SEC 32
+#define NTP_POLL_INTERVAL_MAX_SEC 2048
+
+/*
+ * Maximum delta in seconds which the system clock is gradually adjusted
+ * (slew) 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
+
+/* NTP protocol, packet header */
+#define NTP_LEAP_PLUSSEC 1
+#define NTP_LEAP_MINUSSEC 2
+#define NTP_LEAP_NOTINSYNC 3
+#define NTP_MODE_CLIENT 3
+#define NTP_MODE_SERVER 4
+#define NTP_FIELD_LEAP(f) (((f) >> 6) & 3)
+#define NTP_FIELD_VERSION(f) (((f) >> 3) & 7)
+#define NTP_FIELD_MODE(f) ((f) & 7)
+#define NTP_FIELD(l, v, m) (((l) << 6) | ((v) << 3) | (m))
+
+/*
+ * "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
+ * in seconds relative to 0h on 1 January 1900."
+ */
+#define OFFSET_1900_1970 2208988800UL
+
+struct ntp_ts {
+ be32_t sec;
+ be32_t frac;
+} _packed_;
+
+struct ntp_ts_short {
+ be16_t sec;
+ be16_t frac;
+} _packed_;
+
+struct ntp_msg {
+ uint8_t field;
+ uint8_t stratum;
+ int8_t poll;
+ int8_t precision;
+ struct ntp_ts_short root_delay;
+ struct ntp_ts_short root_dispersion;
+ char refid[4];
+ struct ntp_ts reference_time;
+ struct ntp_ts origin_time;
+ struct ntp_ts recv_time;
+ struct ntp_ts trans_time;
+} _packed_;
+
+typedef struct Manager Manager;
+struct Manager {
+ sd_event *event;
+
+ /* peer */
+ sd_event_source *event_receive;
+ char *server;
+ struct sockaddr_in server_addr;
+ int server_socket;
+ uint64_t packet_count;
+
+ /* last sent packet */
+ struct timespec trans_time_mon;
+ struct timespec trans_time;
+ usec_t retry_interval;
+ bool pending;
+
+ /* poll timer */
+ sd_event_source *event_timer;
+ usec_t poll_interval_usec;
+ bool poll_resync;
+
+ /* history data */
+ struct {
+ double offset;
+ double delay;
+ } samples[8];
+ unsigned int samples_idx;
+ double samples_jitter;
+
+ /* last change */
+ bool jumped;
+
+ /* watch for time changes */
+ sd_event_source *event_clock_watch;
+ int clock_watch_fd;
+};
+
+static void manager_free(Manager *m);
+DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free);
+#define _cleanup_manager_free_ _cleanup_(manager_freep)
+
+static int sntp_arm_timer(Manager *m, usec_t next);
+static int sntp_clock_watch_setup(Manager *m);
+static void sntp_server_disconnect(Manager *m);
+
+static double ntp_ts_to_d(const struct ntp_ts *ts) {
+ return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
+}
+
+static double tv_to_d(const struct timeval *tv) {
+ return tv->tv_sec + (1.0e-6 * tv->tv_usec);
+}
+
+static double ts_to_d(const struct timespec *ts) {
+ return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
+}
+
+static void d_to_tv(double d, struct timeval *tv) {
+ tv->tv_sec = (long)d;
+ tv->tv_usec = (d - tv->tv_sec) * 1000 * 1000;
+
+ /* the kernel expects -0.3s as {-1, 7000.000} */
+ if (tv->tv_usec < 0) {
+ tv->tv_sec -= 1;
+ tv->tv_usec += 1000 * 1000;
+ }
+}
+
+static double square(double d) {
+ return d * d;
+}
+
+static int sntp_send_request(Manager *m) {
+ struct ntp_msg ntpmsg = {};
+ struct sockaddr_in addr = {};
+ ssize_t len;
+ int r;
+
+ /*
+ * "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."
+ */
+ ntpmsg.field = NTP_FIELD(0, 4, NTP_MODE_CLIENT);
+
+ /*
+ * Set transmit timestamp, remember it; the server will send that back
+ * as the origin timestamp and we have an indication that this is the
+ * matching answer to our request.
+ *
+ * The actual value does not matter, We do not care about the correct
+ * NTP UINT_MAX fraction; we just pass the plain nanosecond value.
+ */
+ clock_gettime(CLOCK_MONOTONIC, &m->trans_time_mon);
+ clock_gettime(CLOCK_REALTIME, &m->trans_time);
+ ntpmsg.trans_time.sec = htobe32(m->trans_time.tv_sec + OFFSET_1900_1970);
+ ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
+
+ addr.sin_family = AF_INET;
+ addr.sin_port = htobe16(123);
+ addr.sin_addr.s_addr = inet_addr(m->server);
+ len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &addr, sizeof(addr));
+ if (len == sizeof(ntpmsg)) {
+ m->pending = true;
+ log_debug("Sent NTP request to: %s", m->server);
+ } else
+ log_debug("Sending NTP request to %s failed: %m", m->server);
+
+ /* re-arm timer with incresing timeout, in case the packets never arrive back */
+ if (m->retry_interval > 0) {
+ if (m->retry_interval < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
+ m->retry_interval *= 2;
+ } else
+ m->retry_interval = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
+ r = sntp_arm_timer(m, m->retry_interval);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static int sntp_timer(sd_event_source *source, usec_t usec, void *userdata) {
+ Manager *m = userdata;
+
+ assert(m);
+
+ sntp_send_request(m);
+ return 0;
+}
+
+static int sntp_arm_timer(Manager *m, usec_t next) {
+ int r;
+
+ assert(m);
+ assert(m->event_receive);
+
+ 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(m->event_timer, now(CLOCK_MONOTONIC) + next);
+ if (r < 0)
+ return r;
+
+ return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
+ }
+
+ r = sd_event_add_time(
+ m->event,
+ &m->event_timer,
+ CLOCK_MONOTONIC,
+ now(CLOCK_MONOTONIC) + next, 0,
+ sntp_timer, m);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static int sntp_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
+ Manager *m = userdata;
+
+ assert(m);
+ assert(m->event_receive);
+
+ /* rearm timer */
+ sntp_clock_watch_setup(m);
+
+ /* skip our own jumps */
+ if (m->jumped) {
+ m->jumped = false;
+ return 0;
+ }
+
+ /* resync */
+ log_info("System time changed. Resyncing.");
+ m->poll_resync = true;
+ sntp_send_request(m);
+
+ return 0;
+}
+
+/* wake up when the system time changes underneath us */
+static int sntp_clock_watch_setup(Manager *m) {
+ struct itimerspec its = { .it_value.tv_sec = TIME_T_MAX };
+ _cleanup_close_ int fd = -1;
+ sd_event *e;
+ sd_event_source *source;
+ int r;
+
+ assert(m);
+ assert(m->event_receive);
+
+ fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
+ if (fd < 0) {
+ log_error("Failed to create timerfd: %m");
+ return -errno;
+ }
+
+ if (timerfd_settime(fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0) {
+ log_error("Failed to set up timerfd: %m");
+ return -errno;
+ }
+
+ e = sd_event_source_get_event(m->event_receive);
+ r = sd_event_add_io(e, &source, fd, EPOLLIN, sntp_clock_watch, m);
+ if (r < 0) {
+ log_error("Failed to create clock watch event source: %s", strerror(-r));
+ return r;
+ }
+
+ sd_event_source_unref(m->event_clock_watch);
+ m->event_clock_watch = source;
+
+ if (m->clock_watch_fd >= 0)
+ close(m->clock_watch_fd);
+ m->clock_watch_fd = fd;
+ fd = -1;
+
+ return 0;
+}
+
+static int sntp_adjust_clock(Manager *m, double offset, int leap_sec) {
+ struct timex tmx = {};
+ int r;
+
+ /*
+ * For small deltas, tell the kernel to gradually adjust the system
+ * clock to the NTP time, larger deltas are just directly set.
+ *
+ * Clear STA_UNSYNC, it will enable the kernel's 11-minute mode, which
+ * syncs the system time periodically to the hardware clock.
+ */
+ if (fabs(offset) < NTP_MAX_ADJUST) {
+ tmx.modes = ADJ_STATUS | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR;
+ tmx.status = STA_PLL;
+ tmx.offset = offset * USEC_PER_SEC;
+ tmx.constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 6;
+ tmx.maxerror = 0;
+ tmx.esterror = 0;
+ log_debug(" adjust (slew): %+f sec\n", (double)tmx.offset / USEC_PER_SEC);
+ } else {
+ tmx.modes = ADJ_SETOFFSET;
+ d_to_tv(offset, &tmx.time);
+
+ m->jumped = true;
+ log_debug(" adjust (jump): %+f sec\n", tv_to_d(&tmx.time));
+ }
+
+ switch (leap_sec) {
+ case 1:
+ tmx.status |= STA_INS;
+ break;
+ case -1:
+ tmx.status |= STA_DEL;
+ break;
+ }
+
+ //r = clock_adjtime(CLOCK_REALTIME, &tmx);
+ r = adjtimex(&tmx);
+ if (r < 0)
+ return r;
+
+ log_debug(" status : %04i %s\n"
+ " time now : %li.%06li\n"
+ " constant : %li\n"
+ " offset : %+f sec\n"
+ " freq offset : %+li (%+.3f ppm)\n",
+ tmx.status, tmx.status & STA_UNSYNC ? "" : "sync",
+ tmx.time.tv_sec, tmx.time.tv_usec,
+ tmx.constant,
+ (double)tmx.offset / USEC_PER_SEC,
+ tmx.freq, (double)tmx.freq / 65536);
+
+ return 0;
+}
+
+static bool sntp_sample_spike_detection(Manager *m, double offset, double delay) {
+ unsigned int i, idx_cur, idx_new, idx_min;
+ double jitter;
+ double j;
+
+ 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 += square(m->samples[i].offset - m->samples[idx_min].offset);
+ 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 sntp_adjust_poll(Manager *m, double offset, bool spike) {
+ if (m->poll_resync) {
+ m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
+ m->poll_resync = false;
+ return;
+ }
+
+ /* set to minimal poll interval */
+ if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
+ m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
+ return;
+ }
+
+ /* increase polling interval */
+ if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
+ if (m->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
+ m->poll_interval_usec *= 2;
+ return;
+ }
+
+ /* decrease polling interval */
+ if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
+ if (m->poll_interval_usec > NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC)
+ m->poll_interval_usec /= 2;
+ return;
+ }
+}
+
+static int sntp_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
+ Manager *m = userdata;
+ unsigned char buf[sizeof(struct ntp_msg)];
+ struct iovec iov = {
+ .iov_base = buf,
+ .iov_len = sizeof(buf),
+ };
+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[CMSG_SPACE(sizeof(struct timeval))];
+ } control;
+ struct sockaddr_in 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 cmsghdr *cmsg;
+ struct timespec now_ts;
+ struct timeval *recv_time;
+ ssize_t len;
+ struct ntp_msg *ntpmsg;
+ double origin, receive, trans, dest;
+ double delay, offset;
+ bool spike;
+ int leap_sec;
+ int r;
+
+ if (revents & (EPOLLHUP|EPOLLERR)) {
+ log_debug("Server connection returned error. Closing.");
+ sntp_server_disconnect(m);
+ return -ENOTCONN;
+ }
+
+ len = recvmsg(fd, &msghdr, MSG_DONTWAIT);
+ if (len < 0) {
+ log_debug("Error receiving message. Disconnecting.");
+ return -EINVAL;
+ }
+
+ if (iov.iov_len < sizeof(struct ntp_msg)) {
+ log_debug("Invalid response from server. Disconnecting.");
+ return -EINVAL;
+ }
+
+ if (m->server_addr.sin_addr.s_addr != server_addr.sin_addr.s_addr) {
+ log_debug("Response from unknown server. Disconnecting.");
+ return -EINVAL;
+ }
+
+ recv_time = NULL;
+ for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {
+ if (cmsg->cmsg_level != SOL_SOCKET)
+ continue;
+
+ switch (cmsg->cmsg_type) {
+ case SCM_TIMESTAMP:
+ recv_time = (struct timeval *) CMSG_DATA(cmsg);
+ break;
+ }
+ }
+ if (!recv_time) {
+ log_debug("Invalid packet timestamp. Disconnecting.");
+ return -EINVAL;
+ }
+
+ ntpmsg = iov.iov_base;
+ if (!m->pending) {
+ log_debug("Unexpected reply. Ignoring.");
+ return 0;
+ }
+
+ /* check our "time cookie" (we just stored nanoseconds in the fraction field) */
+ if (be32toh(ntpmsg->origin_time.sec) != m->trans_time.tv_sec + OFFSET_1900_1970 ||
+ be32toh(ntpmsg->origin_time.frac) != m->trans_time.tv_nsec) {
+ log_debug("Invalid reply; not our transmit time. Ignoring.");
+ return 0;
+ }
+
+ if (NTP_FIELD_LEAP(ntpmsg->field) == NTP_LEAP_NOTINSYNC) {
+ log_debug("Server is not synchronized. Disconnecting.");
+ return -EINVAL;
+ }
+
+ if (NTP_FIELD_VERSION(ntpmsg->field) != 4) {
+ log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg->field));
+ return -EINVAL;
+ }
+
+ if (NTP_FIELD_MODE(ntpmsg->field) != NTP_MODE_SERVER) {
+ log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg->field));
+ return -EINVAL;
+ }
+
+ /* valid packet */
+ m->pending = false;
+ m->retry_interval = 0;
+
+ /* 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"
+ */
+ clock_gettime(CLOCK_MONOTONIC, &now_ts);
+ origin = tv_to_d(recv_time) - (ts_to_d(&now_ts) - ts_to_d(&m->trans_time_mon)) + OFFSET_1900_1970;
+ receive = ntp_ts_to_d(&ntpmsg->recv_time);
+ trans = ntp_ts_to_d(&ntpmsg->trans_time);
+ dest = tv_to_d(recv_time) + OFFSET_1900_1970;
+
+ offset = ((receive - origin) + (trans - dest)) / 2;
+ delay = (dest - origin) - (trans - receive);
+
+ spike = sntp_sample_spike_detection(m, offset, delay);
+
+ sntp_adjust_poll(m, offset, spike);
+
+ log_debug("NTP response:\n"
+ " leap : %u\n"
+ " version : %u\n"
+ " mode : %u\n"
+ " stratum : %u\n"
+ " precision : %f sec (%d)\n"
+ " reference : %.4s\n"
+ " origin : %f\n"
+ " receive : %f\n"
+ " transmit : %f\n"
+ " dest : %f\n"
+ " offset : %+f sec\n"
+ " delay : %+f sec\n"
+ " packet count : %"PRIu64"\n"
+ " jitter : %f%s\n"
+ " poll interval: %llu\n",
+ NTP_FIELD_LEAP(ntpmsg->field),
+ NTP_FIELD_VERSION(ntpmsg->field),
+ NTP_FIELD_MODE(ntpmsg->field),
+ ntpmsg->stratum,
+ exp2(ntpmsg->precision), ntpmsg->precision,
+ 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);
+
+ log_info("%4llu %+10f %10f %10f%s",
+ m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, spike ? " spike" : "");
+
+ if (!spike) {
+ r = sntp_adjust_clock(m, offset, leap_sec);
+ if (r < 0)
+ log_error("Failed to call clock_adjtime(): %m");
+ }
+
+ r = sntp_arm_timer(m, m->poll_interval_usec);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static int sntp_server_connect(Manager *m, const char *server) {
+ _cleanup_free_ char *s = NULL;
+
+ assert(m);
+ assert(server);
+ assert(m->server_socket >= 0);
+
+ s = strdup(server);
+ if (!s)
+ return -ENOMEM;
+
+ free(m->server);
+ m->server = s;
+ s = NULL;
+
+ zero(m->server_addr);
+ m->server_addr.sin_family = AF_INET;
+ m->server_addr.sin_addr.s_addr = inet_addr(server);
+
+ m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
+
+ return sntp_send_request(m);
+}
+
+static void sntp_server_disconnect(Manager *m) {
+ if (!m->server)
+ return;
+
+ m->event_timer = sd_event_source_unref(m->event_timer);
+
+ m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
+ if (m->clock_watch_fd > 0)
+ close(m->clock_watch_fd);
+ m->clock_watch_fd = -1;
+
+ m->event_receive = sd_event_source_unref(m->event_receive);
+ if (m->server_socket > 0)
+ close(m->server_socket);
+ m->server_socket = -1;
+
+ zero(m->server_addr);
+ free(m->server);
+ m->server = NULL;
+}
+
+static int sntp_listen_setup(Manager *m) {
+ _cleanup_close_ int fd = -1;
+ struct sockaddr_in addr;
+ const int on = 1;
+ const int tos = IPTOS_LOWDELAY;
+ int r;
+
+ fd = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
+ if (fd < 0)
+ return -errno;
+
+ zero(addr);
+ addr.sin_family = AF_INET;
+ r = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
+ if (r < 0)
+ return -errno;
+
+ r = setsockopt(fd, SOL_SOCKET, SO_TIMESTAMP, &on, sizeof(on));
+ if (r < 0)
+ return -errno;
+
+ r = setsockopt(fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
+ if (r < 0)
+ return -errno;
+
+ r = sd_event_add_io(m->event, &m->event_receive, fd, EPOLLIN, sntp_receive_response, m);
+ if (r < 0)
+ return r;
+
+ m->server_socket = fd;
+ fd = -1;
+
+ return 0;
+}
+
+static int manager_new(Manager **ret) {
+ _cleanup_manager_free_ Manager *m = NULL;
+ int r;
+
+ m = new0(Manager, 1);
+ if (!m)
+ return -ENOMEM;
+
+ r = sd_event_default(&m->event);
+ if (r < 0)
+ return r;
+
+ r = sntp_listen_setup(m);
+ if (r < 0)
+ return r;
+
+ r = sntp_clock_watch_setup(m);
+ if (r < 0)
+ return r;
+
+ *ret = m;
+ m = NULL;
+
+ return 0;
+}
+
+static void manager_free(Manager *m) {
+
+ if (!m)
+ return;
+
+ sd_event_unref(m->event);
+ free(m);
+}
+
+int main(int argc, char *argv[]) {
+ _cleanup_manager_free_ Manager *m = NULL;
+ const char *server;
+ int r;
+
+ log_set_target(LOG_TARGET_AUTO);
+ log_parse_environment();
+ log_open();
+
+ r = manager_new(&m);
+ if (r < 0)
+ goto out;
+
+ //server = "216.239.32.15"; /* time1.google.com */
+ //server = "192.53.103.108"; /* ntp1.ptb.de */
+ server = "27.54.95.11"; /* au.pool.ntp.org */
+
+ sd_notifyf(false,
+ "READY=1\n"
+ "STATUS=Connecting to %s", server);
+
+ r = sntp_server_connect(m, server);
+ if (r < 0)
+ goto out;
+
+ r = sd_event_loop(m->event);
+ if (r < 0)
+ goto out;
+
+out:
+ return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}