Fix printing of NTP poll interval.
The poll value in an NTP packet is a signed integer. For negative values
print the interval as a fraction of second. Also, ignore values outside
of interval (-32, 32).
diff --git a/print-ntp.c b/print-ntp.c
index 0689264..1593ca6 100644
--- a/print-ntp.c
+++ b/print-ntp.c
@@ -116,7 +116,7 @@
struct ntpdata {
u_char status; /* status of local clock and leap info */
u_char stratum; /* Stratum level */
- u_char ppoll; /* poll value */
+ int ppoll:8; /* poll value */
int precision:8;
struct s_fixedpt root_delay;
struct s_fixedpt root_dispersion;
@@ -170,6 +170,7 @@
static void p_sfix(netdissect_options *ndo, const struct s_fixedpt *);
static void p_ntp_time(netdissect_options *, const struct l_fixedpt *);
static void p_ntp_delta(netdissect_options *, const struct l_fixedpt *, const struct l_fixedpt *);
+static void p_poll(netdissect_options *, register const int);
static const struct tok ntp_mode_values[] = {
{ MODE_UNSPEC, "unspecified" },
@@ -236,8 +237,10 @@
bp->stratum,
tok2str(ntp_stratum_values, (bp->stratum >=2 && bp->stratum<=15) ? "secondary reference" : "reserved", bp->stratum)));
- ND_TCHECK(bp->ppoll);
- ND_PRINT((ndo, ", poll %u (%us)", bp->ppoll, 1 << bp->ppoll));
+ /* Can't ND_TCHECK bp->ppoll bitfield so bp->stratum + 2 instead */
+ ND_TCHECK2(bp->stratum, 2);
+ ND_PRINT((ndo, ", poll %d", bp->ppoll));
+ p_poll(ndo, bp->ppoll);
/* Can't ND_TCHECK bp->precision bitfield so bp->distance + 0 instead */
ND_TCHECK2(bp->root_delay, 0);
@@ -425,3 +428,17 @@
ND_PRINT((ndo, "%s%d.%09d", signbit ? "-" : "+", i, f));
}
+/* Prints polling interval in log2 as seconds or fraction of second */
+static void
+p_poll(netdissect_options *ndo,
+ register const int poll)
+{
+ if (poll <= -32 || poll >= 32)
+ return;
+
+ if (poll >= 0)
+ ND_PRINT((ndo, " (%us)", 1U << poll));
+ else
+ ND_PRINT((ndo, " (1/%us)", 1U << -poll));
+}
+
