| /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
| |
| /*** |
| This file is part of systemd. |
| |
| Copyright 2014 Kay Sievers, Lennart Poettering |
| |
| 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 <resolv.h> |
| #include <sys/prctl.h> |
| #include <sys/types.h> |
| #include <grp.h> |
| |
| #include "missing.h" |
| #include "util.h" |
| #include "sparse-endian.h" |
| #include "log.h" |
| #include "socket-util.h" |
| #include "list.h" |
| #include "ratelimit.h" |
| #include "strv.h" |
| #include "conf-parser.h" |
| #include "sd-event.h" |
| #include "sd-resolve.h" |
| #include "sd-daemon.h" |
| #include "sd-network.h" |
| #include "event-util.h" |
| #include "network-util.h" |
| #include "clock-util.h" |
| #include "capability.h" |
| #include "mkdir.h" |
| #include "timesyncd.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 |
| |
| #define RETRY_USEC (30*USEC_PER_SEC) |
| #define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC) |
| #define RATELIMIT_BURST 10 |
| |
| #define TIMEOUT_USEC (10*USEC_PER_SEC) |
| |
| 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_; |
| |
| static void manager_free(Manager *m); |
| DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free); |
| #define _cleanup_manager_free_ _cleanup_(manager_freep) |
| |
| static int manager_arm_timer(Manager *m, usec_t next); |
| static int manager_clock_watch_setup(Manager *m); |
| static int manager_connect(Manager *m); |
| static void manager_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 ts_to_d(const struct timespec *ts) { |
| return ts->tv_sec + (1.0e-9 * ts->tv_nsec); |
| } |
| |
| static double tv_to_d(const struct timeval *tv) { |
| return tv->tv_sec + (1.0e-6 * tv->tv_usec); |
| } |
| |
| static double square(double d) { |
| return d * d; |
| } |
| |
| static int load_clock_timestamp(uid_t uid, gid_t gid) { |
| _cleanup_close_ int fd = -1; |
| usec_t min = TIME_EPOCH * USEC_PER_SEC; |
| usec_t ct; |
| int r; |
| |
| /* Let's try to make sure that the clock is always |
| * monotonically increasing, by saving the clock whenever we |
| * have a new NTP time, or when we shut down, and restoring it |
| * when we start again. This is particularly helpful on |
| * systems lacking a battery backed RTC. We also will adjust |
| * the time to at least the build time of systemd. */ |
| |
| fd = open("/var/lib/systemd/clock", O_RDWR|O_CLOEXEC, 0644); |
| if (fd >= 0) { |
| struct stat st; |
| usec_t stamp; |
| |
| /* check if the recorded time is later than the compiled-in one */ |
| r = fstat(fd, &st); |
| if (r >= 0) { |
| stamp = timespec_load(&st.st_mtim); |
| if (stamp > min) |
| min = stamp; |
| } |
| |
| /* Try to fix the access mode, so that we can still |
| touch the file after dropping priviliges */ |
| fchmod(fd, 0644); |
| fchown(fd, uid, gid); |
| |
| } else |
| /* create stamp file with the compiled-in date */ |
| touch_file("/var/lib/systemd/clock", true, min, uid, gid, 0644); |
| |
| ct = now(CLOCK_REALTIME); |
| if (ct < min) { |
| struct timespec ts; |
| char date[FORMAT_TIMESTAMP_MAX]; |
| |
| log_info("System clock time unset or jumped backwards, restoring from recorded timestamp: %s", |
| format_timestamp(date, sizeof(date), min)); |
| |
| if (clock_settime(CLOCK_REALTIME, timespec_store(&ts, min)) < 0) |
| log_error("Failed to restore system clock: %m"); |
| } |
| |
| return 0; |
| } |
| |
| static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) { |
| _cleanup_free_ char *pretty = NULL; |
| Manager *m = userdata; |
| |
| assert(m); |
| assert(m->current_server_name); |
| assert(m->current_server_address); |
| |
| sockaddr_pretty(&m->current_server_address->sockaddr.sa, m->current_server_address->socklen, true, &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); |
| |
| /* |
| * 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. |
| */ |
| assert_se(clock_gettime(CLOCK_MONOTONIC, &m->trans_time_mon) >= 0); |
| assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0); |
| ntpmsg.trans_time.sec = htobe32(m->trans_time.tv_sec + OFFSET_1900_1970); |
| ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec); |
| |
| sockaddr_pretty(&m->current_server_address->sockaddr.sa, m->current_server_address->socklen, true, &pretty); |
| |
| 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("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) { |
| 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 = manager_arm_timer(m, m->retry_interval); |
| if (r < 0) { |
| log_error("Failed to rearm timer: %s", strerror(-r)); |
| return r; |
| } |
| |
| r = sd_event_add_time( |
| m->event, |
| &m->event_timeout, |
| CLOCK_MONOTONIC, |
| now(CLOCK_MONOTONIC) + TIMEOUT_USEC, 0, |
| manager_timeout, m); |
| if (r < 0) { |
| log_error("Failed to arm timeout timer: %s", strerror(-r)); |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) { |
| Manager *m = userdata; |
| |
| assert(m); |
| |
| return manager_send_request(m); |
| } |
| |
| static int manager_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); |
| } |
| |
| return sd_event_add_time( |
| m->event, |
| &m->event_timer, |
| CLOCK_MONOTONIC, |
| now(CLOCK_MONOTONIC) + next, 0, |
| manager_timer, m); |
| } |
| |
| static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) { |
| Manager *m = userdata; |
| |
| assert(m); |
| |
| /* rearm timer */ |
| manager_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; |
| return manager_send_request(m); |
| } |
| |
| /* wake up when the system time changes underneath us */ |
| static int manager_clock_watch_setup(Manager *m) { |
| |
| struct itimerspec its = { |
| .it_value.tv_sec = TIME_T_MAX |
| }; |
| |
| int r; |
| |
| assert(m); |
| |
| m->event_clock_watch = sd_event_source_unref(m->event_clock_watch); |
| safe_close(m->clock_watch_fd); |
| |
| m->clock_watch_fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC); |
| if (m->clock_watch_fd < 0) { |
| log_error("Failed to create timerfd: %m"); |
| return -errno; |
| } |
| |
| if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0) { |
| log_error("Failed to set up timerfd: %m"); |
| return -errno; |
| } |
| |
| r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, manager_clock_watch, m); |
| if (r < 0) { |
| log_error("Failed to create clock watch event source: %s", strerror(-r)); |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| static int manager_adjust_clock(Manager *m, double offset, int leap_sec) { |
| struct timex tmx = {}; |
| int r; |
| |
| assert(m); |
| |
| /* |
| * 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_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR; |
| tmx.status = STA_PLL; |
| tmx.offset = offset * NSEC_PER_SEC; |
| tmx.constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4; |
| tmx.maxerror = 0; |
| tmx.esterror = 0; |
| log_debug(" adjust (slew): %+.3f sec\n", offset); |
| } else { |
| tmx.modes = ADJ_SETOFFSET | ADJ_NANO; |
| |
| /* ADJ_NANO uses nanoseconds in the microseconds field */ |
| tmx.time.tv_sec = (long)offset; |
| tmx.time.tv_usec = (offset - tmx.time.tv_sec) * 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\n", offset); |
| } |
| |
| switch (leap_sec) { |
| case 1: |
| tmx.status |= STA_INS; |
| break; |
| case -1: |
| tmx.status |= STA_DEL; |
| break; |
| } |
| |
| r = clock_adjtime(CLOCK_REALTIME, &tmx); |
| if (r < 0) |
| return r; |
| |
| touch("/var/lib/systemd/clock"); |
| |
| m->drift_ppm = tmx.freq / 65536; |
| |
| log_debug(" status : %04i %s\n" |
| " time now : %li.%03llu\n" |
| " constant : %li\n" |
| " offset : %+.3f sec\n" |
| " freq offset : %+li (%i ppm)\n", |
| tmx.status, tmx.status & STA_UNSYNC ? "" : "sync", |
| tmx.time.tv_sec, (unsigned long long) (tmx.time.tv_usec / NSEC_PER_MSEC), |
| tmx.constant, |
| (double)tmx.offset / NSEC_PER_SEC, |
| tmx.freq, m->drift_ppm); |
| |
| return 0; |
| } |
| |
| static bool manager_sample_spike_detection(Manager *m, double offset, double delay) { |
| unsigned int 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 += 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 manager_adjust_poll(Manager *m, double offset, bool spike) { |
| assert(m); |
| |
| 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 bool sockaddr_equal(union sockaddr_union *a, union sockaddr_union *b) { |
| assert(a); |
| assert(b); |
| |
| if (a->sa.sa_family != b->sa.sa_family) |
| return false; |
| |
| if (a->sa.sa_family == AF_INET) |
| return a->in.sin_addr.s_addr == b->in.sin_addr.s_addr; |
| |
| if (a->sa.sa_family == AF_INET6) |
| return memcmp(&a->in6.sin6_addr, &b->in6.sin6_addr, sizeof(a->in6.sin6_addr)) == 0; |
| |
| return false; |
| } |
| |
| static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) { |
| Manager *m = userdata; |
| struct ntp_msg ntpmsg; |
| |
| struct iovec iov = { |
| .iov_base = &ntpmsg, |
| .iov_len = sizeof(ntpmsg), |
| }; |
| union { |
| struct cmsghdr cmsghdr; |
| uint8_t buf[CMSG_SPACE(sizeof(struct timeval))]; |
| } 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 cmsghdr *cmsg; |
| struct timespec now_ts; |
| struct timeval *recv_time; |
| ssize_t len; |
| double origin, receive, trans, dest; |
| double delay, offset; |
| bool spike; |
| int leap_sec; |
| int r; |
| |
| assert(source); |
| assert(m); |
| |
| if (revents & (EPOLLHUP|EPOLLERR)) { |
| log_warning("Server connection returned error."); |
| return manager_connect(m); |
| } |
| |
| len = recvmsg(fd, &msghdr, MSG_DONTWAIT); |
| if (len < 0) { |
| if (errno == EAGAIN) |
| return 0; |
| |
| log_warning("Error receiving message. Disconnecting."); |
| return manager_connect(m); |
| } |
| |
| if (iov.iov_len < sizeof(struct ntp_msg)) { |
| 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 = 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_error("Invalid packet timestamp."); |
| return -EINVAL; |
| } |
| |
| 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; |
| } |
| |
| 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) { |
| 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); |
| } |
| |
| /* 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" |
| */ |
| assert_se(clock_gettime(CLOCK_MONOTONIC, &now_ts) >= 0); |
| 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 = manager_sample_spike_detection(m, offset, delay); |
| |
| manager_adjust_poll(m, offset, spike); |
| |
| log_debug("NTP response:\n" |
| " leap : %u\n" |
| " version : %u\n" |
| " mode : %u\n" |
| " stratum : %u\n" |
| " precision : %.6f sec (%d)\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, |
| 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); |
| |
| if (!spike) { |
| m->sync = true; |
| r = manager_adjust_clock(m, offset, leap_sec); |
| if (r < 0) |
| log_error("Failed to call clock_adjtime(): %m"); |
| } |
| |
| log_info("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+ippm%s", |
| m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_ppm, |
| spike ? " (ignored)" : ""); |
| |
| r = manager_arm_timer(m, m->poll_interval_usec); |
| if (r < 0) { |
| log_error("Failed to rearm timer: %s", strerror(-r)); |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| static int manager_listen_setup(Manager *m) { |
| union sockaddr_union addr = {}; |
| static const int tos = IPTOS_LOWDELAY; |
| static const int on = 1; |
| int r; |
| |
| assert(m); |
| |
| assert(m->server_socket < 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(m->server_socket, SOL_SOCKET, SO_TIMESTAMP, &on, sizeof(on)); |
| if (r < 0) |
| return -errno; |
| |
| setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)); |
| |
| return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m); |
| } |
| |
| 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->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC; |
| |
| sockaddr_pretty(&m->current_server_address->sockaddr.sa, m->current_server_address->socklen, true, &pretty); |
| log_info("Using NTP server %s (%s).", strna(pretty), m->current_server_name->string); |
| sd_notifyf(false, "STATUS=Using Time Server %s (%s).", strna(pretty), m->current_server_name->string); |
| |
| r = manager_listen_setup(m); |
| if (r < 0) { |
| log_warning("Failed to setup connection socket: %s", strerror(-r)); |
| return r; |
| } |
| |
| r = manager_clock_watch_setup(m); |
| if (r < 0) |
| return r; |
| |
| return manager_send_request(m); |
| } |
| |
| static void server_name_flush_addresses(ServerName *n) { |
| ServerAddress *a; |
| |
| assert(n); |
| |
| while ((a = n->addresses)) { |
| LIST_REMOVE(addresses, n->addresses, a); |
| free(a); |
| } |
| } |
| |
| static void manager_flush_names(Manager *m) { |
| ServerName *n; |
| |
| assert(m); |
| |
| while ((n = m->servers)) { |
| LIST_REMOVE(names, m->servers, n); |
| free(n->string); |
| server_name_flush_addresses(n); |
| free(n); |
| } |
| } |
| |
| static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) { |
| Manager *m = userdata; |
| ServerAddress *a, *last = NULL; |
| |
| 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); |
| } |
| |
| server_name_flush_addresses(m->current_server_name); |
| |
| for (; ai; ai = ai->ai_next) { |
| _cleanup_free_ char *pretty = NULL; |
| |
| assert(ai->ai_addr); |
| assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data)); |
| assert(ai->ai_addrlen <= sizeof(union sockaddr_union)); |
| |
| if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) { |
| log_warning("Unsuitable address protocol for %s", m->current_server_name->string); |
| continue; |
| } |
| |
| a = new0(ServerAddress, 1); |
| if (!a) |
| return log_oom(); |
| |
| memcpy(&a->sockaddr, ai->ai_addr, ai->ai_addrlen); |
| a->socklen = ai->ai_addrlen; |
| |
| LIST_INSERT_AFTER(addresses, m->current_server_name->addresses, last, a); |
| last = a; |
| |
| sockaddr_pretty(&a->sockaddr.sa, a->socklen, true, &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); |
| } |
| |
| m->current_server_address = m->current_server_name->addresses; |
| |
| return manager_begin(m); |
| } |
| |
| static int manager_retry(sd_event_source *source, usec_t usec, void *userdata) { |
| Manager *m = userdata; |
| |
| assert(m); |
| |
| return manager_connect(m); |
| } |
| |
| static int manager_connect(Manager *m) { |
| |
| struct addrinfo hints = { |
| .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG, |
| .ai_socktype = SOCK_DGRAM, |
| }; |
| int r; |
| |
| assert(m); |
| |
| manager_disconnect(m); |
| |
| m->event_retry = sd_event_source_unref(m->event_retry); |
| if (!ratelimit_test(&m->ratelimit)) { |
| log_debug("Slowing down attempts to contact servers."); |
| |
| r = sd_event_add_time(m->event, &m->event_retry, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + RETRY_USEC, 0, manager_retry, m); |
| if (r < 0) { |
| log_error("Failed to create retry timer: %s", strerror(-r)); |
| return r; |
| } |
| |
| 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) |
| m->current_server_address = m->current_server_address->addresses_next; |
| else { |
| /* Hmm, we are through all addresses, let's look for the next host instead */ |
| m->current_server_address = NULL; |
| |
| if (m->current_server_name && m->current_server_name->names_next) |
| m->current_server_name = m->current_server_name->names_next; |
| else { |
| if (!m->servers) { |
| m->current_server_name = NULL; |
| log_debug("No server found."); |
| return 0; |
| } |
| |
| m->current_server_name = m->servers; |
| } |
| |
| /* Tell the resolver to reread /etc/resolv.conf, in |
| * case it changed. */ |
| res_init(); |
| |
| r = sd_resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, m); |
| if (r < 0) { |
| log_error("Failed to create resolver: %s", strerror(-r)); |
| return r; |
| } |
| |
| return 1; |
| } |
| |
| r = manager_begin(m); |
| if (r < 0) |
| return r; |
| |
| return 1; |
| } |
| |
| static int manager_add_server(Manager *m, const char *server) { |
| ServerName *n, *tail; |
| |
| assert(m); |
| assert(server); |
| |
| n = new0(ServerName, 1); |
| if (!n) |
| return -ENOMEM; |
| |
| n->string = strdup(server); |
| if (!n->string) { |
| free(n); |
| return -ENOMEM; |
| } |
| |
| LIST_FIND_TAIL(names, m->servers, tail); |
| LIST_INSERT_AFTER(names, m->servers, tail, n); |
| |
| return 0; |
| } |
| |
| static int manager_add_server_string(Manager *m, const char *string) { |
| char *w, *state; |
| size_t l; |
| int r; |
| |
| assert(m); |
| assert(string); |
| |
| FOREACH_WORD_QUOTED(w, l, string, state) { |
| char t[l+1]; |
| |
| memcpy(t, w, l); |
| t[l] = 0; |
| |
| r = manager_add_server(m, t); |
| if (r < 0) |
| log_error("Failed to add server %s to configuration, ignoring: %s", t, strerror(-r)); |
| } |
| |
| return 0; |
| } |
| |
| static 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); |
| |
| m->event_receive = sd_event_source_unref(m->event_receive); |
| m->server_socket = safe_close(m->server_socket); |
| |
| m->event_clock_watch = sd_event_source_unref(m->event_clock_watch); |
| m->clock_watch_fd = safe_close(m->clock_watch_fd); |
| |
| m->event_timeout = sd_event_source_unref(m->event_timeout); |
| |
| sd_notifyf(false, "STATUS=Idle."); |
| } |
| |
| static int manager_new(Manager **ret) { |
| _cleanup_manager_free_ Manager *m = NULL; |
| int r; |
| |
| m = new0(Manager, 1); |
| if (!m) |
| return -ENOMEM; |
| |
| m->server_socket = m->clock_watch_fd = -1; |
| |
| RATELIMIT_INIT(m->ratelimit, RATELIMIT_INTERVAL_USEC, RATELIMIT_BURST); |
| |
| r = sd_event_default(&m->event); |
| if (r < 0) |
| return r; |
| |
| sd_event_set_watchdog(m->event, true); |
| |
| sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL); |
| sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL); |
| |
| 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_clock_watch_setup(m); |
| if (r < 0) |
| return r; |
| |
| *ret = m; |
| m = NULL; |
| |
| return 0; |
| } |
| |
| static void manager_free(Manager *m) { |
| if (!m) |
| return; |
| |
| manager_disconnect(m); |
| manager_flush_names(m); |
| |
| sd_event_source_unref(m->event_retry); |
| |
| sd_event_source_unref(m->network_event_source); |
| sd_network_monitor_unref(m->network_monitor); |
| |
| sd_resolve_unref(m->resolve); |
| sd_event_unref(m->event); |
| |
| free(m); |
| } |
| |
| int config_parse_servers( |
| const char *unit, |
| const char *filename, |
| unsigned line, |
| const char *section, |
| unsigned section_line, |
| const char *lvalue, |
| int ltype, |
| const char *rvalue, |
| void *data, |
| void *userdata) { |
| |
| Manager *m = userdata; |
| |
| assert(filename); |
| assert(lvalue); |
| assert(rvalue); |
| |
| manager_flush_names(m); |
| manager_add_server_string(m, rvalue); |
| |
| return 0; |
| } |
| |
| static int manager_parse_config_file(Manager *m) { |
| static const char fn[] = "/etc/systemd/timesyncd.conf"; |
| _cleanup_fclose_ FILE *f = NULL; |
| int r; |
| |
| assert(m); |
| |
| f = fopen(fn, "re"); |
| if (!f) { |
| if (errno == ENOENT) |
| return 0; |
| |
| log_warning("Failed to open configuration file %s: %m", fn); |
| return -errno; |
| } |
| |
| r = config_parse(NULL, fn, f, "Time\0", config_item_perf_lookup, |
| (void*) timesyncd_gperf_lookup, false, false, m); |
| if (r < 0) |
| log_warning("Failed to parse configuration file: %s", strerror(-r)); |
| |
| return r; |
| } |
| |
| static bool network_is_online(void) { |
| _cleanup_free_ char *state = NULL; |
| int r; |
| |
| r = sd_network_get_operational_state(&state); |
| if (r >= 0 && STR_IN_SET(state, "routable", "degraded")) |
| return true; |
| |
| return false; |
| } |
| |
| static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, |
| void *userdata) { |
| Manager *m = userdata; |
| bool connected, online; |
| int r; |
| |
| assert(m); |
| |
| /* check if the machine is online */ |
| online = network_is_online(); |
| |
| /* check if the client is currently connected */ |
| connected = (m->server_socket != -1); |
| |
| if (connected && !online) { |
| log_info("No network connectivity, watching for changes."); |
| manager_disconnect(m); |
| } else if (!connected && online) { |
| log_info("Network configuration changed, trying to establish connection."); |
| if (m->current_server_address) { |
| r = manager_begin(m); |
| if (r < 0) |
| return r; |
| } else { |
| r = manager_connect(m); |
| if (r < 0) |
| return r; |
| } |
| } |
| |
| sd_network_monitor_flush(m->network_monitor); |
| |
| return 0; |
| } |
| |
| static int manager_network_monitor_listen(Manager *m) { |
| _cleanup_event_source_unref_ sd_event_source *event_source = NULL; |
| _cleanup_network_monitor_unref_ sd_network_monitor *monitor = NULL; |
| int r, fd, events; |
| |
| r = sd_network_monitor_new(NULL, &monitor); |
| if (r < 0) |
| return r; |
| |
| fd = sd_network_monitor_get_fd(monitor); |
| if (fd < 0) |
| return fd; |
| |
| events = sd_network_monitor_get_events(monitor); |
| if (events < 0) |
| return events; |
| |
| r = sd_event_add_io(m->event, &event_source, fd, events, |
| &manager_network_event_handler, m); |
| if (r < 0) |
| return r; |
| |
| m->network_monitor = monitor; |
| m->network_event_source = event_source; |
| monitor = NULL; |
| event_source = NULL; |
| |
| return 0; |
| } |
| |
| static int drop_privileges(uid_t uid, gid_t gid) { |
| |
| static const cap_value_t bits[] = { |
| CAP_SYS_TIME, |
| }; |
| |
| _cleanup_cap_free_ cap_t d = NULL; |
| int r; |
| |
| /* Unfortunately we cannot leave privilege dropping to PID 1 |
| * here, since we want to run as user but want to keep te |
| * CAP_SYS_TIME capability. Since file capabilities have been |
| * introduced this cannot be done across exec() anymore, |
| * unless our binary has the capability configured in the file |
| * system, which we want to avoid. */ |
| |
| if (setresgid(gid, gid, gid) < 0) { |
| log_error("Failed change group ID: %m"); |
| return -errno; |
| } |
| |
| if (setgroups(0, NULL) < 0) { |
| log_error("Failed to drop auxiliary groups list: %m"); |
| return -errno; |
| } |
| |
| if (prctl(PR_SET_KEEPCAPS, 1) < 0) { |
| log_error("Failed to enable keep capabilities flag: %m"); |
| return -errno; |
| } |
| |
| r = setresuid(uid, uid, uid); |
| if (r < 0) { |
| log_error("Failed change user ID: %m"); |
| return -errno; |
| } |
| |
| if (prctl(PR_SET_KEEPCAPS, 0) < 0) { |
| log_error("Failed to disable keep capabilities flag: %m"); |
| return -errno; |
| } |
| |
| r = capability_bounding_set_drop(~(1ULL << CAP_SYS_TIME), true); |
| if (r < 0) { |
| log_error("Failed to drop capabilities: %s", strerror(-r)); |
| return r; |
| } |
| |
| d = cap_init(); |
| if (!d) |
| return log_oom(); |
| |
| if (cap_set_flag(d, CAP_EFFECTIVE, ELEMENTSOF(bits), bits, CAP_SET) < 0 || |
| cap_set_flag(d, CAP_PERMITTED, ELEMENTSOF(bits), bits, CAP_SET) < 0) { |
| log_error("Failed to enable capabilities bits: %m"); |
| return -errno; |
| } |
| |
| if (cap_set_proc(d) < 0) { |
| log_error("Failed to increase capabilities: %m"); |
| return -errno; |
| } |
| |
| return 0; |
| } |
| |
| int main(int argc, char *argv[]) { |
| const char *user = "systemd-timesync"; |
| _cleanup_manager_free_ Manager *m = NULL; |
| uid_t uid; |
| gid_t gid; |
| int r; |
| |
| if (argc > 1) { |
| log_error("This program does not take arguments."); |
| return EXIT_FAILURE; |
| } |
| |
| log_set_target(LOG_TARGET_AUTO); |
| log_set_facility(LOG_CRON); |
| log_parse_environment(); |
| log_open(); |
| |
| umask(0022); |
| |
| r = get_user_creds(&user, &uid, &gid, NULL, NULL); |
| if (r < 0) { |
| log_error("Cannot resolve user name %s: %s", user, strerror(-r)); |
| return r; |
| } |
| |
| r = load_clock_timestamp(uid, gid); |
| if (r < 0) |
| goto out; |
| |
| r = drop_privileges(uid, gid); |
| if (r < 0) |
| goto out; |
| |
| assert_se(sigprocmask_many(SIG_BLOCK, SIGTERM, SIGINT, -1) == 0); |
| |
| r = manager_new(&m); |
| if (r < 0) { |
| log_error("Failed to allocate manager: %s", strerror(-r)); |
| goto out; |
| } |
| |
| manager_add_server_string(m, NTP_SERVERS); |
| manager_parse_config_file(m); |
| |
| r = manager_network_monitor_listen(m); |
| if (r < 0) { |
| log_error("Failed to listen to networkd events: %s", strerror(-r)); |
| goto out; |
| } |
| |
| log_debug("systemd-timesyncd running as pid %lu", (unsigned long) getpid()); |
| sd_notify(false, "READY=1"); |
| |
| if (network_is_online()) { |
| r = manager_connect(m); |
| if (r < 0) |
| goto out; |
| } |
| |
| r = sd_event_loop(m->event); |
| if (r < 0) { |
| log_error("Failed to run event loop: %s", strerror(-r)); |
| goto out; |
| } |
| |
| sd_event_get_exit_code(m->event, &r); |
| |
| /* if we got an authoritative time, store it in the file system */ |
| if (m->sync) |
| touch("/var/lib/systemd/clock"); |
| |
| out: |
| sd_notify(false, "STATUS=Shutting down..."); |
| |
| return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; |
| } |