timesyncd: the IP_TOS sockopt is really just an optimization, we shouldn't fail if...

[elogind.git] / src / timesync / timesyncd-manager.c

diff --git a/src/timesync/timesyncd-manager.c b/src/timesync/timesyncd-manager.c
index 2b0580cf0197bbf0f45930bdb3c9dae10309a03e..3ae01eb8fc934643bc7592c3f70599b1d1393b3e 100644 (file)
--- a/src/timesync/timesyncd-manager.c
+++ b/src/timesync/timesyncd-manager.c
@@ -54,8 +54,7 @@
 #include "mkdir.h"
 #include "timesyncd-conf.h"
 #include "timesyncd-manager.h"
-
-#define TIME_T_MAX (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
+#include "time-util.h"
 
 #ifndef ADJ_SETOFFSET
 #define ADJ_SETOFFSET                   0x0100  /* add 'time' to current time */
@@ -89,6 +88,12 @@
 #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."
@@ -128,6 +133,10 @@ struct ntp_msg {
 static int manager_arm_timer(Manager *m, usec_t next);
 static int manager_clock_watch_setup(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);
 }
@@ -212,15 +221,18 @@ static int manager_send_request(Manager *m) {
                 return r;
         }
 
-        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) {
-                log_error("Failed to arm timeout timer: %s", strerror(-r));
-                return r;
+        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) {
+                        log_error("Failed to arm timeout timer: %s", strerror(-r));
+                        return r;
+                }
         }
 
         return 0;
@@ -500,6 +512,7 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
         ssize_t len;
         double origin, receive, trans, dest;
         double delay, offset;
+        double root_distance;
         bool spike;
         int leap_sec;
         int r;
@@ -554,6 +567,8 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
                 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) {
@@ -585,6 +600,12 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
                 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;
@@ -626,6 +647,7 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
                   "  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"
@@ -641,6 +663,7 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
                   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,
@@ -697,7 +720,7 @@ static int manager_listen_setup(Manager *m) {
         if (r < 0)
                 return -errno;
 
-        setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
+        (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);
 }
@@ -710,7 +733,9 @@ static int manager_begin(Manager *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;
+        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_info("Using NTP server %s (%s).", strna(pretty), m->current_server_name->string);
@@ -750,8 +775,11 @@ void manager_set_server_address(Manager *m, ServerAddress *a) {
         if (m->current_server_address == a)
                 return;
 
-        m->current_server_name = a ? a->name : NULL;
         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);
 
@@ -856,6 +884,7 @@ int manager_connect(Manager *m) {
                         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
@@ -872,6 +901,8 @@ int manager_connect(Manager *m) {
                                 f = m->link_servers;
                                 if (!f)
                                         f = m->system_servers;
+                                else
+                                        restart = false;
                         }
 
                         if (!f)
@@ -883,6 +914,25 @@ int manager_connect(Manager *m) {
                                 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) {
+                                        log_error("Failed to create retry timer: %s", strerror(-r));
+                                        return r;
+                                }
+
+                                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);
                 }
 
@@ -1023,7 +1073,7 @@ static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t re
         online = network_is_online();
 
         /* check if the client is currently connected */
-        connected = m->server_socket >= 0 || m->resolve_query;
+        connected = m->server_socket >= 0 || m->resolve_query || m->exhausted_servers;
 
         if (connected && !online) {
                 log_info("No network connectivity, watching for changes.");