diff options
Diffstat (limited to 'src/systemd-timesync/timesyncd-manager.c')
| -rw-r--r-- | src/systemd-timesync/timesyncd-manager.c | 1156 |
1 files changed, 1156 insertions, 0 deletions
diff --git a/src/systemd-timesync/timesyncd-manager.c b/src/systemd-timesync/timesyncd-manager.c new file mode 100644 index 0000000000..6a4b52af69 --- /dev/null +++ b/src/systemd-timesync/timesyncd-manager.c @@ -0,0 +1,1156 @@ +/*** + 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 <errno.h> +#include <math.h> +#include <netinet/in.h> +#include <netinet/ip.h> +#include <resolv.h> +#include <stdlib.h> +#include <sys/socket.h> +#include <sys/timerfd.h> +#include <sys/timex.h> +#include <sys/types.h> +#include <time.h> + +#include <systemd/sd-daemon.h> + +#include "alloc-util.h" +#include "fd-util.h" +#include "fs-util.h" +#include "list.h" +#include "log.h" +#include "missing.h" +#include "network-util.h" +#include "ratelimit.h" +#include "socket-util.h" +#include "sparse-endian.h" +#include "string-util.h" +#include "strv.h" +#include "time-util.h" +#include "timesyncd-conf.h" +#include "timesyncd-manager.h" +#include "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 + +/* + * "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)) + +/* Maximum acceptable root distance in seconds. */ +#define NTP_MAX_ROOT_DISTANCE 5.0 + +/* Maximum number of missed replies before selecting another source. */ +#define NTP_MAX_MISSED_REPLIES 2 + +/* + * "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 UINT64_C(2208988800) + +#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 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 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 = userdata; + + assert(m); + 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) + return log_warning_errno(r, "Failed to setup connection socket: %m"); + + /* + * 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_boottime_or_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); + + server_address_pretty(m->current_server_address, &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_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) { + 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) + 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_or_monotonic(), + now(clock_boottime_or_monotonic()) + 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 = userdata; + + assert(m); + + 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(m->event_timer, now(clock_boottime_or_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_boottime_or_monotonic(), + now(clock_boottime_or_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_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) { + + 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) + return log_error_errno(errno, "Failed to create timerfd: %m"); + + if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0) + return log_error_errno(errno, "Failed to set up timerfd: %m"); + + r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, 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 = {}; + 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. + */ + 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", offset); + } else { + tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET; + + /* 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", 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; + } + + r = clock_adjtime(CLOCK_REALTIME, &tmx); + if (r < 0) + return -errno; + + /* If touch fails, there isn't much we can do. Maybe it'll work next time. */ + (void) 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 ? "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 += 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 = 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 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 *recv_time; + ssize_t len; + double origin, receive, trans, dest; + double delay, offset; + double root_distance; + 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); + } + + /* 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 = NULL; + CMSG_FOREACH(cmsg, &msghdr) { + if (cmsg->cmsg_level != SOL_SOCKET) + continue; + + switch (cmsg->cmsg_type) { + case SCM_TIMESTAMPNS: + recv_time = (struct timespec *) CMSG_DATA(cmsg); + break; + } + } + if (!recv_time) { + log_error("Invalid packet timestamp."); + return -EINVAL; + } + + if (!m->pending) { + log_debug("Unexpected reply. Ignoring."); + return 0; + } + + m->missed_replies = 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 || + 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 > NTP_MAX_ROOT_DISTANCE) { + log_debug("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 : %u\n" + " version : %u\n" + " mode : %u\n" + " stratum : %u\n" + " precision : %.6f sec (%d)\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); + + if (!spike) { + m->sync = true; + r = manager_adjust_clock(m, offset, leap_sec); + if (r < 0) + log_error_errno(r, "Failed to call clock_adjtime(): %m"); + } + + log_debug("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)" : ""); + + if (!m->good) { + _cleanup_free_ char *pretty = NULL; + + m->good = true; + + server_address_pretty(m->current_server_address, &pretty); + log_info("Synchronized to time server %s (%s).", strna(pretty), m->current_server_name->string); + sd_notifyf(false, "STATUS=Synchronized to time server %s (%s).", strna(pretty), m->current_server_name->string); + } + + 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 = {}; + static const int tos = IPTOS_LOWDELAY; + static const int on = 1; + 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(m->server_socket, SOL_SOCKET, SO_TIMESTAMPNS, &on, sizeof(on)); + if (r < 0) + return -errno; + + (void) 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 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->good = false; + m->missed_replies = NTP_MAX_MISSED_REPLIES; + if (m->poll_interval_usec == 0) + m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC; + + server_address_pretty(m->current_server_address, &pretty); + log_debug("Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string); + 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, void *userdata) { + Manager *m = userdata; + 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_warning("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 = userdata; + + assert(m); + + 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_test(&m->ratelimit)) { + log_debug("Slowing down attempts to contact servers."); + + r = sd_event_add_time(m->event, &m->event_retry, clock_boottime_or_monotonic(), now(clock_boottime_or_monotonic()) + 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 { + struct addrinfo hints = { + .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG, + .ai_socktype = SOCK_DGRAM, + }; + + /* 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 system list, then the link list. + * After having processed the link list we + * jump back to the system list. However, if + * both lists are empty, we change to the + * fallback list. */ + if (!m->current_server_name || m->current_server_name->type == SERVER_LINK) { + f = m->system_servers; + if (!f) + f = m->link_servers; + } else { + f = m->link_servers; + if (!f) + f = m->system_servers; + else + restart = false; + } + + 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) { + log_debug("Waiting after exhausting servers."); + r = sd_event_add_time(m->event, &m->event_retry, clock_boottime_or_monotonic(), now(clock_boottime_or_monotonic()) + 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 < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC) + 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); + + r = sd_resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, 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_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."); +} + +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); +} + +void manager_free(Manager *m) { + if (!m) + return; + + manager_disconnect(m); + manager_flush_server_names(m, SERVER_SYSTEM); + manager_flush_server_names(m, SERVER_LINK); + 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_resolve_unref(m->resolve); + sd_event_unref(m->event); + + free(m); +} + +static int manager_network_read_link_servers(Manager *m) { + _cleanup_strv_free_ char **ntp = NULL; + ServerName *n, *nx; + char **i; + int r; + + assert(m); + + r = sd_network_get_ntp(&ntp); + if (r < 0) + goto clear; + + LIST_FOREACH(names, n, m->link_servers) + n->marked = true; + + STRV_FOREACH(i, ntp) { + bool found = false; + + 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) + goto clear; + } + } + + LIST_FOREACH_SAFE(names, n, nx, m->link_servers) + if (n->marked) + server_name_free(n); + + return 0; + +clear: + manager_flush_server_names(m, SERVER_LINK); + return r; +} + +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); + + sd_network_monitor_flush(m->network_monitor); + + manager_network_read_link_servers(m); + + /* check if the machine is online */ + online = network_is_online(); + + /* check if the client is currently connected */ + connected = m->server_socket >= 0 || m->resolve_query || m->exhausted_servers; + + 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); + 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 < 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 = 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 = manager_parse_server_string(m, SERVER_FALLBACK, NTP_SERVERS); + if (r < 0) + return r; + + r = sd_event_default(&m->event); + if (r < 0) + return r; + + sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL); + sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL); + + sd_event_set_watchdog(m->event, true); + + 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; + + manager_network_read_link_servers(m); + + *ret = m; + m = NULL; + + return 0; +} |