diff options
Diffstat (limited to 'src/timesync/timesyncd.c')
-rw-r--r-- | src/timesync/timesyncd.c | 368 |
1 files changed, 217 insertions, 151 deletions
diff --git a/src/timesync/timesyncd.c b/src/timesync/timesyncd.c index 3cf3579576..a66d1e46c0 100644 --- a/src/timesync/timesyncd.c +++ b/src/timesync/timesyncd.c @@ -39,6 +39,7 @@ #include "log.h" #include "socket-util.h" #include "sd-event.h" +#include "sd-resolve.h" #include "sd-daemon.h" #define TIME_T_MAX (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1) @@ -108,11 +109,14 @@ struct ntp_msg { typedef struct Manager Manager; struct Manager { sd_event *event; + sd_resolve *resolve; /* peer */ + sd_resolve_query *resolve_query; sd_event_source *event_receive; char *server; union sockaddr_union server_addr; + socklen_t server_addr_length; int server_socket; uint64_t packet_count; @@ -142,15 +146,17 @@ struct Manager { /* watch for time changes */ sd_event_source *event_clock_watch; int clock_watch_fd; + + /* Handle SIGINT/SIGTERM */ + sd_event_source *sigterm, *sigint; }; 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 int manager_arm_timer(Manager *m, usec_t next); +static int manager_clock_watch_setup(Manager *m); static double ntp_ts_to_d(const struct ntp_ts *ts) { return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX); @@ -168,7 +174,7 @@ static double square(double d) { return d * d; } -static int sntp_send_request(Manager *m) { +static int manager_send_request(Manager *m) { struct ntp_msg ntpmsg = { /* * "The client initializes the NTP message header, sends the request @@ -179,14 +185,7 @@ static int sntp_send_request(Manager *m) { */ .field = NTP_FIELD(0, 4, NTP_MODE_CLIENT), }; - - union sockaddr_union addr = { - .in.sin_family = AF_INET, - .in.sin_port = htobe16(123), - }; ssize_t len; - int r; - /* * Set transmit timestamp, remember it; the server will send that back @@ -196,13 +195,12 @@ static int sntp_send_request(Manager *m) { * 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); + 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); - addr.in.sin_addr.s_addr = inet_addr(m->server); - len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &addr.sa, sizeof(addr.in)); + len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->server_addr.sa, m->server_addr_length); if (len == sizeof(ntpmsg)) { m->pending = true; log_debug("Sent NTP request to: %s", m->server); @@ -215,23 +213,19 @@ static int sntp_send_request(Manager *m) { 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; + return manager_arm_timer(m, m->retry_interval); } -static int sntp_timer(sd_event_source *source, usec_t usec, void *userdata) { +static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) { Manager *m = userdata; assert(m); - sntp_send_request(m); - return 0; + return manager_send_request(m); } -static int sntp_arm_timer(Manager *m, usec_t next) { +static int manager_arm_timer(Manager *m, usec_t next) { int r; assert(m); @@ -250,26 +244,21 @@ static int sntp_arm_timer(Manager *m, usec_t next) { return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT); } - r = sd_event_add_time( + return 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; + manager_timer, m); } -static int sntp_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) { +static int manager_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); + manager_clock_watch_setup(m); /* skip our own jumps */ if (m->jumped) { @@ -280,56 +269,49 @@ static int sntp_clock_watch(sd_event_source *source, int fd, uint32_t revents, v /* resync */ log_info("System time changed. Resyncing."); m->poll_resync = true; - sntp_send_request(m); - - return 0; + return manager_send_request(m); } /* wake up when the system time changes underneath us */ -static int sntp_clock_watch_setup(Manager *m) { +static int manager_clock_watch_setup(Manager *m) { struct itimerspec its = { .it_value.tv_sec = TIME_T_MAX }; - _cleanup_close_ int fd = -1; - sd_event_source *source; int r; assert(m); - assert(m->event_receive); - fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC); - if (fd < 0) { + m->event_clock_watch = sd_event_source_unref(m->event_clock_watch); + m->clock_watch_fd = 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(fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0) { + 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, &source, fd, EPOLLIN, sntp_clock_watch, m); + 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; } - sd_event_source_unref(m->event_clock_watch); - m->event_clock_watch = source; - - safe_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) { +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. @@ -391,11 +373,13 @@ static int sntp_adjust_clock(Manager *m, double offset, int leap_sec) { return 0; } -static bool sntp_sample_spike_detection(Manager *m, double offset, double delay) { +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 */ @@ -440,7 +424,9 @@ static bool sntp_sample_spike_detection(Manager *m, double offset, double delay) return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter; } -static void sntp_adjust_poll(Manager *m, double offset, bool spike) { +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; @@ -468,12 +454,29 @@ static void sntp_adjust_poll(Manager *m, double offset, bool spike) { } } -static int sntp_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) { +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; - unsigned char buf[sizeof(struct ntp_msg)]; + struct ntp_msg ntpmsg; + struct iovec iov = { - .iov_base = buf, - .iov_len = sizeof(buf), + .iov_base = &ntpmsg, + .iov_len = sizeof(ntpmsg), }; union { struct cmsghdr cmsghdr; @@ -492,7 +495,6 @@ static int sntp_receive_response(sd_event_source *source, int fd, uint32_t reven 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; @@ -500,15 +502,17 @@ static int sntp_receive_response(sd_event_source *source, int fd, uint32_t reven int r; if (revents & (EPOLLHUP|EPOLLERR)) { - log_debug("Server connection returned error. Closing."); - sntp_server_disconnect(m); + log_debug("Server connection returned error."); return -ENOTCONN; } len = recvmsg(fd, &msghdr, MSG_DONTWAIT); if (len < 0) { + if (errno == EAGAIN) + return 0; + log_debug("Error receiving message. Disconnecting."); - return -EINVAL; + return -errno; } if (iov.iov_len < sizeof(struct ntp_msg)) { @@ -516,7 +520,7 @@ static int sntp_receive_response(sd_event_source *source, int fd, uint32_t reven return -EINVAL; } - if (m->server_addr.in.sin_addr.s_addr != server_addr.in.sin_addr.s_addr) { + if (!sockaddr_equal(&server_addr, &m->server_addr)) { log_debug("Response from unknown server. Disconnecting."); return -EINVAL; } @@ -537,31 +541,30 @@ static int sntp_receive_response(sd_event_source *source, int fd, uint32_t reven 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) { + 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) { + 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)); + 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)); + if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) { + log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field)); return -EINVAL; } @@ -570,9 +573,9 @@ static int sntp_receive_response(sd_event_source *source, int fd, uint32_t reven m->retry_interval = 0; /* announce leap seconds */ - if (NTP_FIELD_LEAP(ntpmsg->field) & NTP_LEAP_PLUSSEC) + if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC) leap_sec = 1; - else if (NTP_FIELD_LEAP(ntpmsg->field) & NTP_LEAP_MINUSSEC) + else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC) leap_sec = -1; else leap_sec = 0; @@ -588,18 +591,18 @@ static int sntp_receive_response(sd_event_source *source, int fd, uint32_t reven * 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); + 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); + 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); + spike = manager_sample_spike_detection(m, offset, delay); - sntp_adjust_poll(m, offset, spike); + manager_adjust_poll(m, offset, spike); log_debug("NTP response:\n" " leap : %u\n" @@ -617,12 +620,12 @@ static int sntp_receive_response(sd_event_source *source, int fd, uint32_t reven " packet count : %"PRIu64"\n" " jitter : %.3f%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", + 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, @@ -633,7 +636,7 @@ static int sntp_receive_response(sd_event_source *source, int fd, uint32_t reven m->poll_interval_usec / USEC_PER_SEC); if (!spike) { - r = sntp_adjust_clock(m, offset, leap_sec); + r = manager_adjust_clock(m, offset, leap_sec); if (r < 0) log_error("Failed to call clock_adjtime(): %m"); } @@ -641,89 +644,132 @@ static int sntp_receive_response(sd_event_source *source, int fd, uint32_t reven log_info("%s: interval/delta/delay/jitter/drift %llus/%+.3fs/%.3fs/%.3fs/%+ippm%s", m->server, m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_ppm, spike ? " (ignored)" : ""); - r = sntp_arm_timer(m, m->poll_interval_usec); - if (r < 0) - return r; - return 0; + return manager_arm_timer(m, m->poll_interval_usec); } -static int sntp_server_connect(Manager *m, const char *server) { - _cleanup_free_ char *s = NULL; +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(server); - assert(m->server_socket >= 0); - s = strdup(server); - if (!s) - return -ENOMEM; + assert(m->server_socket < 0); + assert(!m->event_receive); - free(m->server); - m->server = s; - s = NULL; + addr.sa.sa_family = m->server_addr.sa.sa_family; - zero(m->server_addr); - m->server_addr.in.sin_family = AF_INET; - m->server_addr.in.sin_addr.s_addr = inet_addr(server); + m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0); + if (m->server_socket < 0) + return -errno; - m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC; + r = bind(m->server_socket, &addr.sa, m->server_addr_length); + 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 sntp_send_request(m); + return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m); } -static void sntp_server_disconnect(Manager *m) { - if (!m->server) - return; +static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) { + _cleanup_free_ char *pretty = NULL; + Manager *m = userdata; + int r; - m->event_timer = sd_event_source_unref(m->event_timer); + assert(q); + assert(m); - m->event_clock_watch = sd_event_source_unref(m->event_clock_watch); - m->clock_watch_fd = safe_close(m->clock_watch_fd); + m->resolve_query = sd_resolve_query_unref(m->resolve_query); - m->event_receive = sd_event_source_unref(m->event_receive); - m->server_socket = safe_close(m->server_socket); + if (ret != 0) { + log_error("Failed to resolve %s: %s", m->server, gai_strerror(ret)); + return -EHOSTUNREACH; + } - zero(m->server_addr); - free(m->server); - m->server = NULL; + assert(ai); + 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("Failed to find IP address for %s", m->server); + return -EHOSTUNREACH; + } + + memcpy(&m->server_addr, ai->ai_addr, ai->ai_addrlen); + m->server_addr_length = ai->ai_addrlen; + + r = sockaddr_pretty(&m->server_addr.sa, m->server_addr_length, true, &pretty); + if (r < 0) { + log_warning("Failed to decode address of %s: %s", m->server, strerror(-r)); + return r; + } + + log_debug("Connecting to NTP server %s.", pretty); + sd_notifyf(false, "STATUS=Using Time Server %s", pretty); + + 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) { + log_warning("Failed to setup clock watch: %s", strerror(-r)); + return r; + } + + return manager_send_request(m); } -static int sntp_listen_setup(Manager *m) { +static int manager_connect(Manager *m, const char *server) { - union sockaddr_union addr = { - .in.sin_family = AF_INET, + struct addrinfo hints = { + .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG, + .ai_socktype = SOCK_DGRAM, }; - _cleanup_close_ int fd = -1; - const int on = 1; - const int tos = IPTOS_LOWDELAY; - int r; + assert(m); + assert(server); - fd = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0); - if (fd < 0) - return -errno; + if (m->server) + return -EBUSY; - r = bind(fd, &addr.sa, sizeof(addr.in)); - if (r < 0) - return -errno; + m->server = strdup(server); + if (!m->server) + return -ENOMEM; - r = setsockopt(fd, SOL_SOCKET, SO_TIMESTAMP, &on, sizeof(on)); - if (r < 0) - return -errno; + m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC; - r = setsockopt(fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)); - if (r < 0) - return -errno; + return sd_resolve_getaddrinfo(m->resolve, &m->resolve_query, m->server, "123", &hints, manager_resolve_handler, m); +} - r = sd_event_add_io(m->event, &m->event_receive, fd, EPOLLIN, sntp_receive_response, m); - if (r < 0) - return r; +static void manager_disconnect(Manager *m) { + assert(m); - m->server_socket = fd; - fd = -1; + m->resolve_query = sd_resolve_query_unref(m->resolve_query); - return 0; + 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); + + zero(m->server_addr); + m->server_addr_length = 0; + + free(m->server); + m->server = NULL; + + m->event_clock_watch = sd_event_source_unref(m->event_clock_watch); + m->clock_watch_fd = safe_close(m->clock_watch_fd); } static int manager_new(Manager **ret) { @@ -734,15 +780,24 @@ static int manager_new(Manager **ret) { if (!m) return -ENOMEM; + m->server_socket = m->clock_watch_fd = -1; + r = sd_event_default(&m->event); if (r < 0) return r; - r = sntp_listen_setup(m); + sd_event_add_signal(m->event, &m->sigterm, SIGTERM, NULL, NULL); + sd_event_add_signal(m->event, &m->sigint, SIGINT, NULL, NULL); + + r = sd_resolve_default(&m->resolve); if (r < 0) return r; - r = sntp_clock_watch_setup(m); + r = sd_resolve_attach_event(m->resolve, m->event, 0); + if (r < 0) + return 0; + + r = manager_clock_watch_setup(m); if (r < 0) return r; @@ -753,40 +808,51 @@ static int manager_new(Manager **ret) { } static void manager_free(Manager *m) { - if (!m) return; + manager_disconnect(m); + + sd_event_source_unref(m->sigint); + sd_event_source_unref(m->sigterm); + + sd_resolve_unref(m->resolve); 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(); + assert_se(sigprocmask_many(SIG_BLOCK, SIGTERM, SIGINT, -1) == 0); + r = manager_new(&m); - if (r < 0) + if (r < 0) { + log_error("Failed to allocate manager: %s", strerror(-r)); goto out; - - server = "216.239.32.15"; /* time1.google.com */ + } sd_notify(false, "READY=1"); - r = sntp_server_connect(m, server); - if (r < 0) + r = manager_connect(m, "time1.google.com"); + if (r < 0) { + log_error("Failed to initiate connection: %s", strerror(-r)); goto out; - - sd_notifyf(false, "STATUS=Using Time Server: %s", server); + } r = sd_event_loop(m->event); - if (r < 0) + if (r < 0) { + log_error("Failed to run event loop: %s", strerror(-r)); goto out; + } + + sd_event_get_exit_code(m->event, &r); out: return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; |