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+/*
+ * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that: (1) source code distributions
+ * retain the above copyright notice and this paragraph in its entirety, (2)
+ * distributions including binary code include the above copyright notice and
+ * this paragraph in its entirety in the documentation or other materials
+ * provided with the distribution, and (3) all advertising materials mentioning
+ * features or use of this software display the following acknowledgement:
+ * ``This product includes software developed by the University of California,
+ * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
+ * the University nor the names of its contributors may be used to endorse
+ * or promote products derived from this software without specific prior
+ * written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "ntp.h"
+
+#include "extract.h"
+
+#define JAN_1970 INT64_T_CONSTANT(2208988800) /* 1970 - 1900 in seconds */
+
+void
+p_ntp_time(netdissect_options *ndo,
+ const struct l_fixedpt *lfp)
+{
+ uint32_t i;
+ uint32_t uf;
+ uint32_t f;
+ double ff;
+
+ i = GET_BE_U_4(lfp->int_part);
+ uf = GET_BE_U_4(lfp->fraction);
+ ff = uf;
+ if (ff < 0.0) /* some compilers are buggy */
+ ff += FMAXINT;
+ ff = ff / FMAXINT; /* shift radix point by 32 bits */
+ f = (uint32_t)(ff * 1000000000.0); /* treat fraction as parts per billion */
+ ND_PRINT("%u.%09u", i, f);
+
+ /*
+ * print the UTC time in human-readable format.
+ */
+ if (i) {
+ int64_t seconds_64bit = (int64_t)i - JAN_1970;
+ time_t seconds;
+ char time_buf[128];
+ const char *time_string;
+
+ seconds = (time_t)seconds_64bit;
+ if (seconds != seconds_64bit) {
+ /*
+ * It doesn't fit into a time_t, so we can't hand it
+ * to gmtime.
+ */
+ time_string = "[Time is too large to fit into a time_t]";
+ } else {
+ /* use ISO 8601 (RFC3339) format */
+ time_string = nd_format_time(time_buf, sizeof (time_buf),
+ "%Y-%m-%dT%H:%M:%SZ", gmtime(&seconds));
+ }
+ ND_PRINT(" (%s)", time_string);
+ }
+}