[Bug 3031] modify deadband

bk: 56fc4b55LToEJpD3DOz_xfHWa8QyGg

diff --git a/ntpd/ntp_proto.c b/ntpd/ntp_proto.c
index d757b5bf284922df6941498d5d0ee63ece8413ed..b3e803d91ba1b3457bc5c92eef48722de83e3a95 100644 (file)
--- a/ntpd/ntp_proto.c
+++ b/ntpd/ntp_proto.c
@@ -1308,9 +1308,9 @@ receive(
 #endif /* AUTOKEY */
 
                if (MODE_BROADCAST == hismode) {
-                       u_char poll;
-                       int bail = 0;
-                       l_fp tdiff;
+                       int     bail = 0;
+                       l_fp    tdiff;
+                       u_long  deadband;
 
                        DPRINTF(2, ("receive: PROCPKT/BROADCAST: prev pkt %ld seconds ago, ppoll: %d, %d secs\n",
                                    (current_time - peer->timelastrec),
@@ -1332,27 +1332,28 @@ receive(
                                        peer->ppoll, pkt->ppoll);
                        }
 
-                       poll = min(peer->maxpoll,
-                                  max(peer->minpoll, pkt->ppoll));
-
                        /* This is error-worthy */
-                       if (pkt->ppoll != poll) {
+                       if (pkt->ppoll < peer->minpoll ||
+                           pkt->ppoll > peer->maxpoll  ) {
                                msyslog(LOG_INFO, "receive: broadcast poll of %ud from %s is out-of-range (%d to %d)!",
                                        pkt->ppoll, stoa(&rbufp->recv_srcadr),
                                        peer->minpoll, peer->maxpoll);
                                ++bail;
                        }
 
-                       if (  (current_time - peer->timelastrec)
-                           < (1u << pkt->ppoll) - 1) {
-                               msyslog(LOG_INFO, "receive: broadcast packet from %s arrived after %ld, not %d seconds!",
+                       /* too early? worth an error, too! */
+                       deadband = (1u << pkt->ppoll);
+                       if (FLAG_BC_VOL & peer->flags)
+                               deadband -= 3;  /* allow greater fuzz after volley */
+                       if ((current_time - peer->timelastrec) < deadband) {
+                               msyslog(LOG_INFO, "receive: broadcast packet from %s arrived after %lu, not %lu seconds!",
                                        stoa(&rbufp->recv_srcadr),
                                        (current_time - peer->timelastrec),
-                                       (1 << pkt->ppoll)
-                                       );
+                                       deadband);
                                ++bail;
                        }
 
+                       /* not monotonic? There's a trickser out there! */
                        tdiff = p_xmt;
                        L_SUB(&tdiff, &peer->bxmt);
                        if (tdiff.l_i < 0) {