| /*-*- 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/>. |
| ***/ |
| |
| /* |
| * "Simple Network Time Protocol Version 4 (SNTPv4) is a subset of the |
| * Network Time Protocol (NTP) used to synchronize computer clocks in |
| * the Internet. SNTPv4 can be used when the ultimate performance of |
| * a full NTP implementation based on RFC 1305 is neither needed nor |
| * justified." |
| * |
| * "Unlike most NTP clients, SNTP clients normally operate with only a |
| * single server at a time." |
| * |
| * http://tools.ietf.org/html/rfc4330 |
| */ |
| |
| #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 "timedate-sntp.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 |
| |
| /* Maximum delta in seconds which the system clock is gradually adjusted |
| * to approach the network time. Deltas larger that this are set by letting |
| * the system time jump. The maximum for adjtime is 500ms. |
| */ |
| #define NTP_MAX_ADJUST 0.2 |
| |
| /* |
| * "Define the required accuracy of the system clock, then calculate the |
| * maximum timeout. Use the longest maximum timeout possible given the system |
| * constraints to minimize time server aggregate load." |
| * |
| * "A client MUST NOT under any conditions use a poll interval less |
| * than 15 seconds." |
| */ |
| #define NTP_POLL_INTERVAL_MIN_SEC 16 |
| #define NTP_POLL_INTERVAL_MAX_SEC 2048 |
| #define NTP_ACCURACY_SEC 0.1 |
| |
| #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_; |
| |
| struct SNTPContext { |
| void (*report)(usec_t poll, double offset, double delay, double jitter, bool spike); |
| |
| /* 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 int sntp_arm_timer(SNTPContext *sntp, usec_t next); |
| static int sntp_clock_watch_setup(SNTPContext *sntp); |
| |
| 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(SNTPContext *sntp) { |
| 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, &sntp->trans_time_mon); |
| clock_gettime(CLOCK_REALTIME, &sntp->trans_time); |
| ntpmsg.trans_time.sec = htobe32(sntp->trans_time.tv_sec + OFFSET_1900_1970); |
| ntpmsg.trans_time.frac = htobe32(sntp->trans_time.tv_nsec); |
| |
| addr.sin_family = AF_INET; |
| addr.sin_port = htobe16(123); |
| addr.sin_addr.s_addr = inet_addr(sntp->server); |
| len = sendto(sntp->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &addr, sizeof(addr)); |
| if (len == sizeof(ntpmsg)) { |
| sntp->pending = true; |
| log_debug("Sent NTP request to: %s", sntp->server); |
| } else |
| log_debug("Sending NTP request to %s failed: %m", sntp->server); |
| |
| /* re-arm timer with incresing timeout, in case the packets never arrive back */ |
| if (sntp->retry_interval > 0) { |
| if (sntp->retry_interval < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC) |
| sntp->retry_interval *= 2; |
| } else |
| sntp->retry_interval = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC; |
| r = sntp_arm_timer(sntp, sntp->retry_interval); |
| if (r < 0) |
| return r; |
| |
| return 0; |
| } |
| |
| static int sntp_timer(sd_event_source *source, usec_t usec, void *userdata) { |
| SNTPContext *sntp = userdata; |
| |
| assert(sntp); |
| |
| sntp_send_request(sntp); |
| return 0; |
| } |
| |
| static int sntp_arm_timer(SNTPContext *sntp, usec_t next) { |
| sd_event *e; |
| int r; |
| |
| assert(sntp); |
| assert(sntp->event_receive); |
| |
| if (next == 0) { |
| sntp->event_timer = sd_event_source_unref(sntp->event_timer); |
| return 0; |
| } |
| |
| if (sntp->event_timer) { |
| r = sd_event_source_set_time(sntp->event_timer, now(CLOCK_MONOTONIC) + next); |
| if (r < 0) |
| return r; |
| |
| return sd_event_source_set_enabled(sntp->event_timer, SD_EVENT_ONESHOT); |
| } |
| |
| e = sd_event_source_get_event(sntp->event_receive); |
| r = sd_event_add_time( |
| e, |
| &sntp->event_timer, |
| CLOCK_MONOTONIC, |
| now(CLOCK_MONOTONIC) + next, 0, |
| sntp_timer, sntp); |
| if (r < 0) |
| return r; |
| |
| return 0; |
| } |
| |
| static int sntp_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) { |
| SNTPContext *sntp = userdata; |
| |
| assert(sntp); |
| assert(sntp->event_receive); |
| |
| /* rearm timer */ |
| sntp_clock_watch_setup(sntp); |
| |
| /* skip our own jumps */ |
| if (sntp->jumped) { |
| sntp->jumped = false; |
| return 0; |
| } |
| |
| /* resync */ |
| log_info("System time changed. Resyncing."); |
| sntp->poll_resync = true; |
| sntp_send_request(sntp); |
| |
| return 0; |
| } |
| |
| /* wake up when the system time changes underneath us */ |
| static int sntp_clock_watch_setup(SNTPContext *sntp) { |
| 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(sntp); |
| assert(sntp->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(sntp->event_receive); |
| r = sd_event_add_io(e, &source, fd, EPOLLIN, sntp_clock_watch, sntp); |
| if (r < 0) { |
| log_error("Failed to create clock watch event source: %s", strerror(-r)); |
| return r; |
| } |
| |
| sd_event_source_unref(sntp->event_clock_watch); |
| sntp->event_clock_watch = source; |
| |
| if (sntp->clock_watch_fd >= 0) |
| close(sntp->clock_watch_fd); |
| sntp->clock_watch_fd = fd; |
| fd = -1; |
| |
| return 0; |
| } |
| |
| static int sntp_adjust_clock(SNTPContext *sntp, 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 (offset < NTP_MAX_ADJUST && offset > -NTP_MAX_ADJUST) { |
| tmx.modes |= ADJ_STATUS | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR; |
| tmx.status = STA_PLL; |
| tmx.offset = offset * 1000 * 1000; |
| tmx.constant = log2i(sntp->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); |
| |
| sntp->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); |
| 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(SNTPContext *sntp, double offset, double delay) { |
| unsigned int i, idx_cur, idx_new, idx_min; |
| double jitter; |
| double j; |
| |
| /* store the current data in our samples array */ |
| idx_cur = sntp->samples_idx; |
| idx_new = (idx_cur + 1) % ELEMENTSOF(sntp->samples); |
| sntp->samples_idx = idx_new; |
| sntp->samples[idx_new].offset = offset; |
| sntp->samples[idx_new].delay = delay; |
| |
| sntp->packet_count++; |
| jitter = sntp->samples_jitter; |
| |
| /* calculate new jitter value from the RMS differences relative to the lowest delay sample */ |
| for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(sntp->samples); i++) |
| if (sntp->samples[i].delay > 0 && sntp->samples[i].delay < sntp->samples[idx_min].delay) |
| idx_min = i; |
| |
| j = 0; |
| for (i = 0; i < ELEMENTSOF(sntp->samples); i++) |
| j += square(sntp->samples[i].offset - sntp->samples[idx_min].offset); |
| sntp->samples_jitter = sqrt(j / (ELEMENTSOF(sntp->samples) - 1)); |
| |
| /* ignore samples when resyncing */ |
| if (sntp->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 (sntp->packet_count < 4) |
| return false; |
| |
| /* do not accept anything worse than the maximum possible error of the best sample */ |
| if (fabs(offset) > sntp->samples[idx_min].delay) |
| return true; |
| |
| /* compare the difference between the current offset to the previous offset and jitter */ |
| return fabs(offset - sntp->samples[idx_cur].offset) > 3 * jitter; |
| } |
| |
| static void sntp_adjust_poll(SNTPContext *sntp, double offset, bool spike) { |
| if (sntp->poll_resync) { |
| sntp->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC; |
| sntp->poll_resync = false; |
| return; |
| } |
| |
| /* set to minimal poll interval */ |
| if (!spike && fabs(offset) > NTP_ACCURACY_SEC) { |
| sntp->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC; |
| return; |
| } |
| |
| /* increase polling interval */ |
| if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) { |
| if (sntp->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC) |
| sntp->poll_interval_usec *= 2; |
| return; |
| } |
| |
| /* decrease polling interval */ |
| if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) { |
| if (sntp->poll_interval_usec > NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC) |
| sntp->poll_interval_usec /= 2; |
| return; |
| } |
| } |
| |
| static int sntp_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) { |
| SNTPContext *sntp = 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(sntp); |
| 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 (sntp->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 (!sntp->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) != sntp->trans_time.tv_sec + OFFSET_1900_1970 || |
| be32toh(ntpmsg->origin_time.frac) != sntp->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 */ |
| sntp->pending = false; |
| sntp->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(&sntp->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(sntp, offset, delay); |
| |
| sntp_adjust_poll(sntp, 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, |
| sntp->packet_count, |
| sntp->samples_jitter, spike ? " spike" : "", |
| sntp->poll_interval_usec / USEC_PER_SEC); |
| |
| if (sntp->report) |
| sntp->report(sntp->poll_interval_usec, offset, delay, sntp->samples_jitter, spike); |
| |
| if (!spike) { |
| r = sntp_adjust_clock(sntp, offset, leap_sec); |
| if (r < 0) |
| log_error("Failed to call clock_adjtime(): %m"); |
| } |
| |
| r = sntp_arm_timer(sntp, sntp->poll_interval_usec); |
| if (r < 0) |
| return r; |
| |
| return 0; |
| } |
| |
| int sntp_server_connect(SNTPContext *sntp, const char *server) { |
| _cleanup_free_ char *s = NULL; |
| |
| assert(sntp); |
| assert(server); |
| assert(sntp->server_socket >= 0); |
| |
| s = strdup(server); |
| if (!s) |
| return -ENOMEM; |
| |
| free(sntp->server); |
| sntp->server = s; |
| s = NULL; |
| |
| zero(sntp->server_addr); |
| sntp->server_addr.sin_family = AF_INET; |
| sntp->server_addr.sin_addr.s_addr = inet_addr(server); |
| |
| sntp->poll_interval_usec = 2 * NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC; |
| |
| return sntp_send_request(sntp); |
| } |
| |
| void sntp_server_disconnect(SNTPContext *sntp) { |
| if (!sntp->server) |
| return; |
| |
| sntp->event_timer = sd_event_source_unref(sntp->event_timer); |
| |
| sntp->event_clock_watch = sd_event_source_unref(sntp->event_clock_watch); |
| if (sntp->clock_watch_fd > 0) |
| close(sntp->clock_watch_fd); |
| sntp->clock_watch_fd = -1; |
| |
| sntp->event_receive = sd_event_source_unref(sntp->event_receive); |
| if (sntp->server_socket > 0) |
| close(sntp->server_socket); |
| sntp->server_socket = -1; |
| |
| zero(sntp->server_addr); |
| free(sntp->server); |
| sntp->server = NULL; |
| } |
| |
| static int sntp_listen_setup(SNTPContext *sntp, sd_event *e) { |
| _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(e, &sntp->event_receive, fd, EPOLLIN, sntp_receive_response, sntp); |
| if (r < 0) |
| return r; |
| |
| sntp->server_socket = fd; |
| fd = -1; |
| |
| return 0; |
| } |
| |
| void sntp_report_register(SNTPContext *sntp, void (*report)(usec_t poll_usec, double offset, double delay, double jitter, bool spike)) { |
| sntp->report = report; |
| } |
| |
| int sntp_new(SNTPContext **sntp, sd_event *e) { |
| _cleanup_free_ SNTPContext *c; |
| int r; |
| |
| c = new0(SNTPContext, 1); |
| if (!c) |
| return -ENOMEM; |
| |
| r = sntp_listen_setup(c, e); |
| if (r < 0) |
| return r; |
| |
| r = sntp_clock_watch_setup(c); |
| if (r < 0) |
| return r; |
| |
| *sntp = c; |
| c = NULL; |
| |
| return 0; |
| } |
| |
| SNTPContext *sntp_unref(SNTPContext *sntp) { |
| sntp_server_disconnect(sntp); |
| free(sntp); |
| return NULL; |
| } |