ntpd: on time step, kill all outstanding replies from other peers

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/networking/ntpd.c b/networking/ntpd.c
index 603801ec60afcca90f7238bf3d68db537138064c..72e9d0be2161646ba5d6bfd7ff7570b7b219b619 100644 (file)
--- a/networking/ntpd.c
+++ b/networking/ntpd.c
@@ -220,14 +220,14 @@ typedef struct {
 typedef struct {
        len_and_sockaddr *p_lsa;
        char             *p_dotted;
-       /* when to send new query (if p_fd == -1)
-        * or when receive times out (if p_fd >= 0): */
        int              p_fd;
        int              datapoint_idx;
        uint32_t         lastpkt_refid;
        uint8_t          lastpkt_status;
        uint8_t          lastpkt_stratum;
        uint8_t          reachable_bits;
+        /* when to send new query (if p_fd == -1)
+         * or when receive times out (if p_fd >= 0): */
        double           next_action_time;
        double           p_xmttime;
        double           lastpkt_recv_time;
@@ -895,6 +895,11 @@ step_time(double offset)
 
        /* Correct various fields which contain time-relative values: */
 
+       /* Globals: */
+       G.cur_time += offset;
+       G.last_update_recv_time += offset;
+       G.last_script_run += offset;
+
        /* p->lastpkt_recv_time, p->next_action_time and such: */
        for (item = G.ntp_peers; item != NULL; item = item->link) {
                peer_t *pp = (peer_t *) item->data;
@@ -902,11 +907,16 @@ step_time(double offset)
                //bb_error_msg("offset:%+f pp->next_action_time:%f -> %f",
                //      offset, pp->next_action_time, pp->next_action_time + offset);
                pp->next_action_time += offset;
+               if (pp->p_fd >= 0) {
+                       /* We wait for reply from this peer too.
+                        * But due to step we are doing, reply's data is no longer
+                        * useful (in fact, it'll be bogus). Stop waiting for it.
+                        */
+                       close(pp->p_fd);
+                       pp->p_fd = -1;
+                       set_next(pp, RETRY_INTERVAL);
+               }
        }
-       /* Globals: */
-       G.cur_time += offset;
-       G.last_update_recv_time += offset;
-       G.last_script_run += offset;
 }
 
 
@@ -1623,22 +1633,30 @@ recv_and_process_peer_pkt(peer_t *p)
                ) {
 //TODO: always do this?
                        interval = retry_interval();
-                       goto set_next_and_close_sock;
+                       goto set_next_and_ret;
                }
                xfunc_die();
        }
 
        if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
                bb_error_msg("malformed packet received from %s", p->p_dotted);
-               goto bail;
+               return;
        }
 
        if (msg.m_orgtime.int_partl != p->p_xmt_msg.m_xmttime.int_partl
         || msg.m_orgtime.fractionl != p->p_xmt_msg.m_xmttime.fractionl
        ) {
-               goto bail;
+               /* Somebody else's packet */
+               return;
        }
 
+       /* We do not expect any more packets from this peer for now.
+        * Closing the socket informs kernel about it.
+        * We open a new socket when we send a new query.
+        */
+       close(p->p_fd);
+       p->p_fd = -1;
+
        if ((msg.m_status & LI_ALARM) == LI_ALARM
         || msg.m_stratum == 0
         || msg.m_stratum > NTP_MAXSTRATUM
@@ -1647,8 +1665,8 @@ recv_and_process_peer_pkt(peer_t *p)
 // "DENY", "RSTR" - peer does not like us at all
 // "RATE" - peer is overloaded, reduce polling freq
                interval = poll_interval(0);
-               bb_error_msg("reply from %s: not synced, next query in %us", p->p_dotted, interval);
-               goto set_next_and_close_sock;
+               bb_error_msg("reply from %s: peer is unsynced, next query in %us", p->p_dotted, interval);
+               goto set_next_and_ret;
        }
 
 //     /* Verify valid root distance */
@@ -1794,16 +1812,8 @@ recv_and_process_peer_pkt(peer_t *p)
        /* Decide when to send new query for this peer */
        interval = poll_interval(0);
 
- set_next_and_close_sock:
+ set_next_and_ret:
        set_next(p, interval);
-       /* We do not expect any more packets from this peer for now.
-        * Closing the socket informs kernel about it.
-        * We open a new socket when we send a new query.
-        */
-       close(p->p_fd);
-       p->p_fd = -1;
- bail:
-       return;
 }
 
 #if ENABLE_FEATURE_NTPD_SERVER