1 files changed, 74 insertions, 0 deletions
diff --git a/ntp.c b/ntp.c
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+++ b/ntp.c
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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);
+	}
+}